Samsung Electronics Co., Ltd & Anor v ZTE Corporation & Ors [2026] EWHC 2235 (Pat)

[2026] EWHC 2235 (Pat)Case No HP-2024-000044
IN THE HIGH COURT OF JUSTICE
BUSINESS AND PROPERTY COURTS OF ENGLAND AND WALES
INTELLECTUAL PROPERTY LIST (ChD)
PATENTS COURT
Venue Royal Courts of Justice, Rolls Building, Fetter Lane, London, EC4A 1NLDate 28 August 2026
Before
THE HON MR JUSTICE MELLOR
Between
SAMSUNG ELECTRONICS CO., LTDClaimantsSAMSUNG ELECTRONICS (UK) LIMITEDClaimantZTE CORPORATIONDefendantsZTE (UK) LIMITEDDefendantNUBIA TECHNOLOGY CO., LTDDefendantLIVEWIRE TELECOM LIMITEDDefendantEFONES.COM LIMITEDDefendant
BRIAN NICHOLSON KC and JEREMY HEALD (instructed by Kirkland & Ellis International LLP) for ClaimantsMICHAEL TAPPIN KC and NICHOLAS HARRIS (instructed by Powell Gilbert LLP) for DefendantsHearing Hearing dates: 3-5, 10-11 March 2026
APPROVED JUDGMENTThis judgment was handed down remotely by circulation to the parties’ representatives by email.It will also be released for publication on the National Archives and other websites. The date andtime for hand-down is deemed to be Friday 28 August 2026 at 10.30am.THE HON MR JUSTICE MELLOR

INTRODUCTION

[1]This is my judgment from Technical Trial A in these proceedings. It concerns EP(UK) 3,934,154 (‘the Patent’) owned by Samsung. The relevant date for the purposes of these proceedings is the Patent’s unchallenged earliest priority date of 24 February 2017 (‘the Priority Date’). ZTE accept the Patent is essential to the 5G standard and would, in the absence of a licence, be infringed by ZTE’s 5G enabled devices.[2]On that basis, the only issue for trial was whether the Patent was valid. Since ZTE bear the burden of proving invalidity, they opened the trial and called their expert, Dr Shin Horng Wong first. Samsung then called their expert, Mr Nicholas Anderson. Following time for the parties to prepare their written closing submissions, I heard closing arguments on 10th and 11th March 2026.[3]I am only concerned with the validity of claim 1, and both parties accept the remaining claims stand or fall with claim 1. Although I have little visibility of how the issues progressed to trial, it is apparent that shortly before trial Samsung dropped their assertion that claims 2 and 10 were independently valid. The parties provided a very useful reading guide which identified the passages in the experts’ reports which concerned points no longer in issue. From my viewpoint, the trial was conducted very efficiently, as we have come to expect with the high quality representation we frequently benefit from in the Patents Court.[4]The backdrop to this trial is as follows. In these proceedings the Claimants (“Samsung”) seek, in outline: i) declarations that seven Samsung patents are(i) essential to certain standards and(ii) infringed by the Defendants (“ZTE”); ii) a FRAND injunction in respect of the Samsung patents; iii) declarations that two ZTE patents are (i) invalid, (ii) not essential to certain standards and(iii) not infringed by Samsung; iv) determination of FRAND terms for the Samsung patents and/or the ZTE patents; and v) certain declarations regarding FRAND-related matters.[5]ZTE has counterclaimed for revocation of the Samsung patents but has not counterclaimed for infringement of the ZTE patents.[6]In the underlying proceedings I directed at the CMC that there should first be a FRAND trial to determine matters raised by iv) and v) above: that trial commenced on 19 January 2026 before Meade J and closing submissions were completed on 11 February 2026. Judgment was delivered on 1 May 2026: see the Redacted Judgment at [2026] EWHC 999 (Pat). At around the same time (and the precise sequence does not matter), the Chongqing Intermediate People’s Court rendered its decision in the parallel case (in which the trial completed in October 2025) and the Munich 1 Landgericht, when granting ZTE a SEP injunction against Samsung, gave an indication of the terms on which it considered the parties should settle, citing a figure which (after adjustment) was remarkably similar to that arrived at by the Chongqing Court. Notwithstanding the delivery of those judgments, I understand that the dispute between Samsung and ZTE remains unresolved.[7]Reverting to this action, I also directed at the CMC that there should be two technical trials, each relating to one of the Samsung patents: trial A relating to the Patent and trial B relating to EP (UK) 3 837 892. By agreement between the parties, Trial B has now been stayed and the May 2026 trial date was vacated. Samsung contended that the only reason that this Trial A was required to go ahead was because ZTE have, as yet, refused to undertake to take a FRAND licence.[8]As is usual in these cases, both the Patent and the Prior Art use many acronyms. I have attached Mr Anderson’s helpful list of them as the Annex to this Judgment.

Outline of the issues for decision

[9]Outline of the issues for decision The issues for decision concerns familiar topics: i) The identity and attributes of the Skilled Person; ii) Disputed issues as to their CGK; iii) Whether claim 1 was obvious, as alleged by ZTE; iv) Whether claim 1 is a collocation of two independent inventions, and whether each was obvious, as alleged by ZTE; v) Whether the Patent is invalid for lack of plausibility or technical effect.[10]However, more so than usual, the issues are very closely related, a point confirmed by Samsung’s Counsel in his closing submissions when he reiterated how the decisions on the Skilled Person and their CGK needed to be part of the ‘standing back’ review of the obviousness case.[11]I should also add that each side argued their case with great industry and tenacity and for a long time during my preparation of this Judgment, the issues appeared very evenly balanced – features of a case which generally make the Judge’s task more difficult and so it proved in this case.

Introduction to the Patent

[12]Introduction to the Patent The Patent is entitled “Method and Apparatus for Design of NR-SS Burst Set” and has an earliest priority date of 24 February 2017.[13]By February 2017 the 3GPP 4G / LTE system was well developed, and early work was being done on a 5G system known as New Radio or NR.[14]The Patent is a reasonably lengthy document, in which the description extends over some 29 pages with 55 pages of figures. As ZTE submitted, it is a dense document, and it did not seem to me to be disputed that much of the description has little or no direct relevance to claim 1.[15]The Patent focuses on a small but important part of 5G, namely initial access (which also interrelates with aspects of mobility and cell search). This is where a UE has just been turned on (or otherwise has come within the range of the network) and the UE has to determine, at the very earliest stage, what 5G cells exist, and the most basic parameters to enable the mobile to start receiving information about those cells. In due course (and beyond the scope of the Patent), the mobile will start actually negotiating with the network to be able to exchange information.[16]Initial access is required in many cell-based communication systems, including in the then existing digital systems of 2G-4G. However, the enhancements to the new 5G network, especially in terms of the radio bands available, the different operating modes, and the multi-antenna techniques were such that, as Samsung put it, the approach to initial access demanded fresh consideration, including a far more flexible approach to initial access.

The Expert Witnesses

[17]The Expert Witnesses The expert called by ZTE was Dr Shin Horng Wong and Samsung called Mr Nicholas Anderson as their expert witness. Refreshingly, both sides said both experts were highly knowledgeable about the relevant field at around the Priority Date and were able to give clear explanations of what was, in some respects, technically complex subject matter. Both sides acknowledged that the experts were able to assist the Court and were doing their best to assist the Court.[18]Those submissions coincided with the views I formed during the trial, and my analysis since has done nothing to disturb that view. I add one point, however, about Mr Anderson. He is particularly precise in his answers and sometimes the import of them can be missed.

THE SKILLED PERSON

[19]THE SKILLED PERSON Introduction The parties were agreed that in this case a single Skilled Person suffices, but the dispute concerned the attributes of this person. Samsung and Mr Anderson referred to the Skilled Person as an Advanced Development Engineer (ADE). They adopted the acronym TFSS, standing for ‘Topic-Focussed Standards Specialist’, to characterise Dr Wong’s Skilled Person. I will use the same acronyms, without prejudice to the validity or otherwise of the contentions behind them.[20]Samsung’s contention was founded on the notion that the ADE was working on the physical layer of cellular radio telecommunications, responsible for design and enhancement of product features, but without a focus on NR. ZTE contended that Samsung were ignoring the fact that the problem addressed by the Patent is one that arose specifically in cell search and initial access in NR.[21]In order to resolve this important dispute, I was reminded by the parties of the following well-known applicable principles.

Applicable principles

[22]Applicable principles As ZTE submitted, the law on the skilled person was comprehensively reviewed by Birss J in Illumina Cambridge v Latvia MGI Tech [2021] EWHC 57 (Pat) at [58]-[71], from which they emphasised the following passages.[23]At [58] Birss J began by saying:
“Who is the person skilled in the art? Stated generally the law is clear that patents are directed to those likely to have a real and practical interest in the subject matter of the invention. … The real practical interest in the subject matter includes devising the invention itself as well as putting it into practice and so, as was highlighted in Schlumberger v EMGS [2010] EWCA Civ 819, the concept of the person skilled in the art actually applies in two distinct circumstances. In a proper case they may be two different persons (or teams).”
[24]He observed at [60] that, when considering the skilled person for the purpose of devising the invention, Schlumberger had identified one principle as follows:
“In the case of obviousness in view of the state of the art, a key question is generally “what problem was the patentee trying to solve?”
That leads one in turn to consider the art in which the problem in fact lay. It is the notional team in that art which is the relevant team making up the person skilled in the art.”[25]Birss J said that that will be the governing approach in most cases but can lead to trouble. The first type of case in which he said it could lead to trouble was a so-called “problem invention” and the second type was where applying the approach in Schlumberger leads to a very narrowly defined skilled person as explained in the Folding Attic Stairs case, which could be unfair to the inventors. Birss J continued at [63]: “while a too narrow definition could be unfair to the inventors, it could be just as wrong and unfair to the public to define a team so widely that their common general knowledge is so dilute as to make something seem less obvious than it really was”….[26]He then identified a further principle from Schlumberger:
“…the Court, in considering the skills of the notional “person skilled in the art” for the purpose of obviousness will have regard to the reality of the position at the time. What the combined skills (and mind-sets) of real research teams in the art is what matters when one is constructing the notional research team to whom the invention must be obvious…”
[27]Birss J then approved the approach, based on the MedImmune case, of considering whether there was something which could properly be called an established field at the priority date. As he said at [67]:
“the width of the field in which the skilled person operates for the purposes of obviousness … is ultimately governed by what was actually going on up to the priority date.”
[28]He therefore held, at [68], that the correct approach to take to the identification of the skilled person for the purposes of obviousness was:
“(i) To start by asking what problem does the invention aim to solve? (ii) That leads one to consider what the established field which existed was, in which the problem in fact can be located. (iii) It is the notional person in that established field which is the relevant team making up the person skilled in the art.”
[29]In Alcon v Actavis [2021] EWHC 1026 (Pat) Meade J referred to the analysis by Birss J in Illumina HC and said at [31]:
“I intend to apply that approach. I take particular note of: i) The requirements not to be unfair to the patentee by allowing an artificially narrow definition, or unfair to the public (and the defendant) by going so broad as to “dilute” the CGK. Thus, as Counsel for Alcon accepted, there is an element of value judgment in the assessment. ii) The fact that I must consider the real situation at the priority date, and in particular what teams existed. iii) The need to look for an “established field”, which might be a research field or a field of manufacture. iv) The starting point is the identification of the problem that the invention aims to solve.”
[30]As ZTE submitted, the Illumina approach as summarised in Alcon v Actavis has subsequently been applied repeatedly.[31]For their part, Samsung stressed the general approach from Medimmune but complemented that with references to three cases from the mobile phone field in which the standardisation process loomed large. In citing these three cases, it seemed to me that Samsung were inviting factual analogies to be drawn, but whether any are appropriate depends on the facts.[32]Samsung’s first proposition was that care has to be taken not to “write-in” adherence to standardisation for inventions claimed as generally applicable even if they were clearly developed in the context of a standardisation process. This was based on a passage from Philips v Asustek [2018] EWHC 1826 (Pat) at [144], where Arnold J. accepted the defendant’s argument that the skilled person would not, in that case, be restricted to UMTS on the basis that the claims were not so limited and covered any CDMA system. That type of issue does not arise in this case.[33]Samsung’s second proposition was that a patent may assume specialised knowledge, leading necessarily to an especially standard-focused skilled person, but the same does not apply as a matter of course, relying on the judgment of Meade J in Nokia v Oneplus [2023] EWHC 23 (Pat); [2023] RPC 7: 32. Prof Purat in his first report envisaged the skilled person as being one of four classes of person, with the members of two of those classes not being closely connected with RAN1; he further expressed the view that information would only be CGK if known to all four classes. 33. This caused Nokia [the patentee] a potential sufficiency problem with the Patent, since the CGK necessary to understand and implement it is (as is common ground) not to be found in any textbook but only within RAN1. So Nokia instructed Prof Purat to proceed, from his second report onwards, on the basis that the skilled person was either a RAN1 delegate, or someone supporting a RAN1 delegate.[34]In closing, Samsung referred to slightly later paragraphs where Meade J. was addressing the specific facts of that case: 35. …But a remaining point at issue was the level of focus of the notional skilled person on the specific problem which the Patent addresses. It was common ground that there was a focus on the RACH in RAN1 at the time, but the RACH was not ‘an established field’ in the sense considered in the authorities such as Illumina Cambridge Ltd v. Latvia MGI Tech SIA [2021] EWHC 57 (Pat), [2021] RPC 12 and the Optis Cellular Technology LLC v. Apple Retail UK Ltd cases that I decided ([2021] EWHC 537 (Pat), [2022] EWHC 561 (Pat)).[35]And, at [38], where the Judge went on to dismiss an argument that the ‘focus’ on the RACH within RAN 1 could be used to define the Skilled Person:
‘… Talking about ‘focus’ sounds alluring and purposeful, and there will have been some real people within RAN1, just a few, who had that actual focus. But the ‘focus’ argument is just a semantically different way of getting to the ‘blue Venezuelan razor blade’ result deprecated by Birss J (as he then was) in Illumina v Latvia, and is inconsistent with the approach of basing the analysis on an established field.’
[36]Samsung’s third proposition was that there are frequently different categories of engineer who are interested in standardised technology, and care has to be taken as to the specific reasons for adopting (or excluding) any particular sub-set within the broader group of engineers. Samsung took, as their example, Philips v. Asustek again where Arnold J held that it was only those interested in implementing completed standards who ought properly to be excluded from the skilled team: 135. The dispute has two aspects. The first, which I do not consider matters, is whether or not the skilled person could be someone developing products compatible with the Standard. .... 136. So far as the first point is concerned, the experts were agreed that, in addition to(i) standards delegates who regularly attended meetings, there were also(ii) people who either occasionally attended meetings when a specific topic of interest was to be discussed,(iii) people who worked behind the scenes providing support to standards delegates and(iv) people who were developing products compatible with the Standard. The experts also agreed that standards delegates could have a range of experience and abilities, although they tended to be more experienced and some were inventive. They also agreed that people in category (iii) would be kept up to date with discussions in WG1 by those who attended the meetings. 137. It is common ground that the Patent would be of interest to people in categories (i) to (iii). Mr Kahtava considered that the Patent would also be of interest to those in category (iv). Prof Purat distinguished in cross-examination between those who were system engineers considering the future development of products and improvements and those who were purely making commercial products implementing a completed standard. He thought that the Patent was addressed to the former, but not the latter. I am inclined to agree with this, but I do not think it matters. …[37]Samsung’s fourth proposition was that, when it is determined that the skilled person is typified, in the real-world, by a broad collection of individuals with various levels of closeness to the standard-setting process, care has to be taken as to not imbue upon that person an involvement (and, consequently, CGK) based upon the closeness of only some real-world examples of the notional skilled person. On this point they relied on the following paragraphs from my own judgment in Mitsubishi v OnePlus [2021] EWHC 1639 (Pat):14. Where the experts differed was as to the Skilled Person/Team's knowledge of the detail of discussions at the meetings of the 3GPP RAN Working Groups 1 and 2. … Mr Bishop acknowledged that not all members of his team would attend all RAN WG1&2 meetings but maintained they would have an in-depth understanding of their specialist area and would have ready access to and knowledge of 3GPP deliverables as well as the meeting reports/contributions from colleagues who did attend.15. For his part, Mr Anderson did not expect the skilled person to be familiar with the minutes of meetings of the working groups or of technical documents submitted to such meetings which had not been incorporated into approved specifications. He noted, correctly, that there is nothing in the patents to indicate they are focussed on 3GPP systems. He indicated that those with a practical interest in the patents would not have been limited to those engineers who regularly or even occasionally attended the meetings of the 3GPP RAN WG1&2. Although this mini-dispute did not appear to have any impact on anything I have to decide, I incline to Mr Anderson's view because I do not consider the ordinary unimaginative skilled person needed to keep up to date with all the discussions being conducted in the relevant groups at a particular standards setting organisation (even one as influential as 3GPP) to carry out his or her job. They would be aware of the effort to develop a long term evolution of UMTS and would be aware that 3GPP was undertaking an exercise to study and evaluate candidate techniques. They could wait to find out what that organisation had adopted in its approved specifications, although, given a specific need to do so, they were well able to find meeting reports and contributions from the relevant working groups.[38]Finally, Samsung warned that care also has to be taken to avoid incorrectly identifying the skilled person (or member of a team) by imbuing them with skills which are irrelevant to the role of the notional skilled person/team, such as an improper regard to regulatory considerations (see, for example, Teva v. Boehringer [2015] EWHC 2963 (Pat) per Morgan J) or commercial considerations (see, for example, Hallen v. Brabantia [1991] RPC 195, for the same reasons).

Application to the Facts

[39]Application to the Facts Samsung’s submissions In closing, Samsung accused ZTE of mischaracterising Mr Anderson’s Skilled Person as a mere implementer, only interested in building a UE from the final version of the Technical Specifications for 5G. Samsung made it clear that was not their case, relying on this explanation given by Mr Anderson in cross-examination: ‘The way companies often operate, companies cannot afford to wait, normally, for the completion of a standard in order to start development of their products. If they did so, they would be behind the competition, normally…So they would often develop some of the building blocks that go within the product initially, whilst the standard is being developed and they would refine that design as the standard also evolves’ [T3/206/13-21].[40]On that basis, Samsung submitted that Mr Anderson’s Skilled Person is someone with the relevant skillset and who has a genuine interest in the development of initial access in 5G. They are close enough to 3GPP to be following the progress of the development, are thinking about how they are going to implement it, and are working on their ‘building block’, albeit that it may need to be refined later.[41]Samsung also relied on this answer from Dr Wong, where he accepted [T2/86/21-87/5]: …that the standard cannot be developed without attention being paid to how things might actually work in practice…Because otherwise 5G might end up requiring base stations or UEs to do something that is either technically is not feasible at all or can only be done with a huge amount of effort and expense…[42]Dr Wong also said that Mr Anderson’s Skilled Person could take LG 434’s Proposal 2 and “develop something based on what he thinks will work”, and in so doing, could work from the draft TR rather than the detail found in the minutes. His only reservation was that such a Skilled Person, not being mired in RAN1 itself, might end with a proposal that would not be acceptable to the RAN1 working group (see [T2/87/6-88/4]). Dr Wong never suggested that Mr Anderson’s Skilled Person would not be interested in the Patent.[43]Samsung therefore submitted that Mr Anderson’s Skilled Person is thus a very credible Skilled Person who draws a proper balance between the interests of fairness to the Patentee and the Public. Such Skilled Person is not someone who is uninterested in 5G, or trying to work on some other project. They are capable of doing the very thing that is before the Court, namely taking LG 434 and seeking to put it into practice. It is not a case of the patentee unfairly diluting the CGK by trying to broaden the definition of the skilled person to include those who were not thinking about the very application to which the Patent is directed.[44]Samsung and Mr Anderson accept that people typifying Dr Wong’s Skilled Person existed, and that they are also addressees of both the Patent and the cited prior art. Samsung’s argument was that they are(a) exceptionally focused; and(b) RAN1 bound.[45]On their first point, Samsung acknowledged that 3GPP is divided-up into specialist sub-areas, namely 3 separate technical specification groups (TSGs, being Radio Access Network (RAN), Core Network and Services and Systems Aspects), and RAN itself is sub-divided into RAN1, 2, 3 and 4. Samsung also pointed out that, on the specific topic of initial access, Dr Wong was at pains to point out that only a sub-set of individuals contributing to RAN1 would be tasked to this topic (as recognised by parallel meeting streams – see below). Samsung did not dispute this but contended that it is the wrong approach in law to identify the skilled person or team simply by the existence of a pending project.[46]In this regard, Samsung relied on Nokia (see the paragraphs set out above) for the underlying legal principle, but plainly sought to draw a factual analogy between that case and this, arguing that Meade J was faced with a very similar argument in relation to a patent developed in the context of a RAN1 standardisation process. Samsung argued as follows: i) that ZTE is trying precisely the same approach in this case: because there was a specific problem being considered by RAN1, ZTE contends that it is appropriate to define the skilled person as typified by those working on that specific problem. ii) that the issue for ZTE is that ‘initial access and mobility in 5G’ is not an ‘established field’. iii) that an established field would be, for example, the physical layer in telecommunications systems. That broader field would include both Mr Anderson’s Skilled Person and Dr Wong’s. A small set of physical layer specialists were focused on the initial access problem in 5G – but that is not the same as there being an established field of “initial access in 5G”, or even “initial access” – which was described to Mr Anderson in cross-examination merely as a “particular aspect” within the physical layer/RAN1 [T3/218/7-13].[47]Samsung’s position was that the approach of ZTE and Dr Wong was exactly the sort of inappropriately narrow and unfair approach as has been rejected by this Court on at least the 3 occasions cited by Meade J, in accordance with the wider principles of requiring an ‘established field’.[48]Samsung’s second main point was that Dr Wong’s Skilled Person was ‘RAN1 Bound’. Samsung pointed to these answers which Dr Wong gave in cross-examination concerning his Skilled Person who would: “not want to go off in a direction that is different to anything else RAN1 has done” and “they would want something useful or has a high degree of being accepted in 3GPP” (see [T2/85/16-86/8]).[49]On this basis, Samsung submitted that Dr Wong’s Skilled Person has two inappropriate restrictions which guide their approach. First, they consider themselves bound by decisions which they perceive RAN1 has already made. Second, they are only interested in developing something which they anticipate would be acceptable to RAN1.[50]Drawing an analogy with cases like Teva v. Boehringer and Hallen v. Brabantia, Samsung argued that these are aspects of inappropriate restrictions with which the Court is more familiar in the context of, first: regulatory concerns; and second: commercial considerations. These two well-known prohibitions on the freedom of the skilled person have in common the fact that, if they were permitted, they would impose non-technical limitations upon that which would otherwise be a technically obvious course.[51]Samsung’s position was that treating agreements/decisions/ideas of RAN1 as restricting the technical freedom of the skilled person is indistinguishable from a party contending that the skilled person would/would not take a particular course because of ‘regulatory considerations’. It is frequently the case that development decisions that bear on regulatory considerations (as with the decisions in RAN1) have been taken for technical reasons, but it is those technical reasons which need to be considered freely by the skilled person (to the extent they are relevant), not the decision of some regulatory or quasi-regulatory body. Likewise, Dr Wong rather treats RAN1 as if it were his Skilled Person’s ‘customer’. His Skilled Person is uninterested in following technically obvious paths unless he is satisfied that ‘his customer’ – RAN1 - would welcome, or at least be open to, the resultant development.[52]In the present case, Samsung said the objection comes in at the point of defining the skilled person, rather than objecting to some misstep in the obviousness journey (as more commonly occurs with the two limbs they identified). Samsung submitted that it cannot however be a proper approach to the identification of the skilled person to deliberately select so specific an individual such that they are encumbered with ‘regulatory’ and ‘customer’ focuses, which would be improper considerations once that skilled person turns their mind to the question of inventive step.

ZTE’s submissions

[53]ZTE’s submissions ZTE dismissed most of Samsung’s reliance on the case law as them seeking to draw factual analogies. ZTE acknowledged the established principles and addressed them relatively succinctly, as follows.[54]The starting point, as explained in Illumina and Alcon, is the identification of the problem that the invention aims to solve. As can be seen from its title, the Patent is concerned with “Design of NR-SS Burst Set” and the specific problem it seeks to solve is how the index of an SS block will be indicated to the UE in an NR system (Anderson [T3 231/10-16]).[55]The concept of an SS block was something which was new to NR (Anderson [T3/225/5-12]), as was the SS burst set (Anderson [T3 225/13-25]). That means that the Patent and its claims (which, in claim 1, refer to an SS block and an SS block index and which, in claims 2 and 10, refer to an SS burst and an SS burst index) are specific to NR, the 5G system being developed within 3GPP.[56]The Illumina / Alcon approach then requires the Court to consider what the established field was in which the problem in fact could be located, and to consider the real situation at the priority date and in particular what teams existed. The width of the field is ultimately governed by what was actually going on up to the priority date (Illumina at [67]).[57]Here, ZTE contended, the answer is clearly that the relevant problem lay in the field of initial access in NR and would have been addressed by the real teams in RAN1 who were concerned with questions of initial access, cell search and mobility.[58]Dr Wong explained that issues of initial access in NR, including that addressed by the Patent, were being addressed in RAN1 (Wong 2 §9). Mr Anderson agreed that the issue of how to indicate the SS block index was one which would need to be resolved by RAN1 to allow NR base stations and UEs from different manufacturers to interoperate (Anderson [T3 228/23–229/4], see also Wong 2 §12), and that this was an issue with which Dr Wong’s skilled person would concern themselves (Anderson [T3 229/5-8]). Unsurprisingly, there was no suggestion that any teams outside RAN1 were engaged in addressing initial access in NR.[59]Dr Wong’s evidence was that, in RAN1 meetings considering NR, companies would be represented by a team of a few people who were focussed on a specific topic or topics (Wong 1 §29). That was reflected in the agendas and schedules for the meetings, where agenda items were discussed in parallel tracks due to the volume of issues and proposals as well as the complexity and degree of specialisation. NR initial access and mobility had its own agenda item in RAN1 meetings (item 7.1.2) around the Priority Date (see, from the Agreed CGK Statement, [73] below). Mr Anderson agreed that teams of physical layer specialists attending RAN1 would have contained people whose role was to deal with cell search, initial access and mobility (Anderson [T3 218/10-16], and Wong 1 §30).[60]Mr Anderson accepted that the problem which the Patent seeks to solve is one which would be addressed by Dr Wong’s skilled person ([T3 231/13-19]). ZTE also submitted that the prior art in this case was plainly addressed to Dr Wong’s skilled person, rather than Mr Anderson’s (Anderson [T3 272/13-21]).

My conclusions

[61]My conclusions I reached the conclusion that Samsung’s second point (see [48] above) did not bear the weight which they sought to put on it, for two main reasons: i) First, the Skilled Person in this case was inevitably operating in the emerging field of 5G and co-operating with others towards the overall development of the 5G system. It is unreal, in my view, to divorce the thinking of the Skilled Person from that essential context or to say that their approach should pay no attention to the developments so far, recognising of course that until the final TSs were agreed, matters might change. After all, the Patent is clearly talking about fitting into the new NR system. ii) Second, because Samsung’s point was, as I understood it, not that being ‘RAN1 bound’ automatically pointed to non-obvious solutions, but rather that Dr Wong’s Skilled Person might ignore other obvious solutions. So this point is really whether the obviousness arguments in this case were a Brugger v Medic-Aid type situation or not.[62]Reverting to Samsung’s first point – exceptionally focussed – Samsung made the point that both candidate Skilled Persons have the same skillset but that where they differ is as to their ‘focus’ and their CGK as a result of that focus.[63]By the Priority Date it was clear that NR was coming and work was actively underway on various aspects. The problem which the Patent aimed to solve was one that arose specifically in cell search and initial access in NR. It did not relate to any other system (cf not restricted to UMTS in Phillips v Asustek). An additional point is that cell search and initial access in NR was not some peripheral side or optional issue – it was fundamental and likely to have effects in other aspects of the NR system. Bearing in mind that many companies in the industry were working on NR and sending delegates to the relevant working groups, I found Samsung’s position more than a little unreal: that people were working on cell search and initial access but apparently without a focus on NR. In other words, they were working on those aspects in the context of LTE, but not NR. It is true that the relevant working groups were LTE groups, but really only by default until working groups specifically in NR were established.[64]At the same time, there is some force in Samsung’s criticism of Dr Wong’s Skilled Person – in that there may be rather too much focus on the specific topic of cell search and initial access. In other words, the narrowness of the field is unfair to the patentee. However, in view of the agreed skillset of the Skilled Person, this point is really engaged with the scope of their CGK, to which I now turn.[65]To be clear, I found the definition and attributes of Mr Anderson’s Skilled Person somewhat opaque. Initially, it did appear that Samsung were arguing for a Skilled Person who would wait for the relevant final TSs to be agreed, albeit Mr Anderson made it clear (see his answer cited above) that his Skilled Person would develop the relevant building block prior to that occurring. Mr Anderson did not make clear how this would occur, but it would have to have been from some proposal considered (and most probably accepted) in RAN1. Thus, the real difference between the rival contentions appeared to be slight, with the principal point of contention being the scope of their CGK. I keep this in mind.

AGREED CGK

[66]AGREED CGK Sources of CGK A primary source of CGK for the Skilled Person would be the set of 3GPP LTE (4G) Technical Specifications (TS), and in particular, those falling under the responsibility of RAN WG1. These include TS 36.201 (‘LTE physical layer; General description’) and the 36.21x series of specifications listed below, all of which have some relation to the background subject matter of the Patent Within the 36.21x series, there is additionally TS 36.216 (‘Physical layer for relaying operation’), though this has less relevance. : - TS 36.211 (‘Physical channels and modulation’); - TS 36.212 (‘Multiplexing and channel coding’); - TS 36.213 (‘Physical layer procedures’); and - TS 36.214 (‘Physical layer measurements’).[67]By the Priority Date (24 February 2017), Release 13 had been completed (though it remained open to corrections) and work to develop and complete LTE specifications for Release 14 was continuing At the Priority Date, the latest Release-14 versions of the above listed specifications were as follows:- TS 36.201 v14.0.0, TS 36.211 v14.1.0, TS 36.212 v14.1.1, TS 36.213 v14.1.0 and TS 36.214 v14.1.0.- For TS 36.216, the latest version was v13.0.0 (a Release 14 version had not yet been created). . Books describing standardised LTE technology as it stood at this time included: i) “4G, LTE-Advanced Pro and The Road to 5G”, by Erik Dahlman, Stefan Parkvall and Johan Sköld (Third Edition, Academic Press, 2016, hereafter, “Dahlman”). ii) “LTE - The UMTS Long Term Evolution: From Theory to Practice”, Stefania Sesia, Issam Toufik, Matthew Baker, 2nd Edition, 2011 (“Sesia, Toufik and Baker”).[68]The Skilled Person would also be familiar with the fundamental concepts of wireless telecoms taught on undergraduate or postgraduate courses. This would be captured in textbooks such as “Digital Signal Processing”, John Proakis, 4th Edition, 2006 (“Proakis”).[69]3GPP Organisational Context 3GPP, or the Third Generation Partnership Project, is a global collaboration of telecommunications standardisation organisations. It is well known for specifying the Global System for Mobile Communications (“GSM”), a “2G” technology, Universal Mobile Telecommunications System (“UMTS”), a “3G” technology, and Long Term Evolution (“LTE”) telecommunications standards, a “4G” technology.[70]Most of the discussions and decisions regarding development of the 3GPP standards take place at technical meetings throughout the year (typically around 6 times per year at the Priority Date). Each meeting lasts around 4-5 working days. These are attended by delegates who are typically teams of engineers representing manufacturers, network operators and R&D businesses who focus on patent licensing. Meetings are also attended by smaller numbers of academics, independent consultants and other interested parties.[71]Between meetings, and particularly in the weeks leading up to a given meeting, participants submit technical proposals for the standard under development in the form of short documents called “Tdocs”. They are then uploaded and become publicly available on the 3GPP server. Some Tdocs are the subject of discussion within the email reflector ahead of the meeting, but for the most part the Tdocs are presented and debated in person at the 3GPP meetings (or not discussed/debated at all). Tdocs can be submitted by a single company or delegate, or as a joint proposal put forward by multiple companies.[72]Each meeting is chaired by an appointed chairman, and follows a pre-defined schedule (circulated in advance by email and updated during the course of the meeting) which is divided into different agenda items corresponding to different technologies under discussion. Tdocs are marked as being relevant to a particular agenda item and are discussed at that point in the meeting. By the Priority Date, it was common for multiple agenda items to be discussed in parallel tracks. This was due to the volume of issues and proposals as well as the complexity and degree of specialisation in the standard. Although it is not agreed that the schedules for particular RAN1 meetings formed part of the CGK, an example of parallel tracks can be seen in the schedule for the RAN1 #87 meeting shown below (copied from the final version of the meeting report):[73]By way of example, during the Monday agenda items 7.1.2 (NR initial access and mobility) and 7.1.4 (NR scheduling/HARQ aspects) were running in parallel with agenda items 6.1 (LTE Maintenance) and 7.1.3 (NR MIMO). It can be seen that at times there were up to three NR discussion tracks running in parallel in addition to discussion tracks on LTE issues. Therefore, whilst it would be possible for a team of delegates to attend between them all of the agenda items, a single delegate clearly could not.[74]The discussion of each agenda item usually involves the consideration of a number of Tdocs selected by the chair. This results in particular proposals being marked as ‘agreed’ or designated as ‘working assumptions’ in the minutes of the relevant meeting, which are subsequently formatted into a final written report. Some Tdocs may instead be recorded as ‘noted’ which means that they have been considered but not agreed for adoption into the standard, or ‘not treated’ which means that they have not been considered during the formal meeting session. Another way of showing a document was ‘not treated’ was if the Tdoc did not appear in bold type in the meeting report.[75]During the course of each meeting, the RAN1 Chairman would maintain a note of matters considered by the working group. This would be in a standard format following the structure of the meeting agenda and would subsequently become the formal meeting report (the final report was sometimes also referred to as the ‘meeting minutes’). It was conventional practice for the RAN1 Chairman to publish an initial draft of the meeting report at the end of the meeting, or within a few days of it ending, on the 3GPP public server. This draft was therefore often referred to as the Chairman’s Note, and would reflect which proposals had been ‘agreed’, ‘noted’, ‘not treated’, etc but would still be in a rough form.[76]Over the course of the following days or weeks a tidier final version would be produced, with more consistent formatting, corrected typographical errors and filling in any missing quotations or document references.[77]The 3GPP meeting reports often incorporate shorthand expressions, some of which are technical acronyms and some of which are non-technical terms to refer to the development process which have been developed over the years by delegates. Some of the most common in RAN1 at the Priority Date were “WF” (meaning “Way Forward”, a company’s or group of companies’ proposal for development); “LS” (meaning “Liaison Statement”, a communication to or from another working group); “WA” (meaning “Working Assumption”); and “FFS” (meaning “For Further Study”).[78]As can be seen from the schedule above for the #87 meeting, incoming LSs which had been received in advance of a meeting were conventionally considered early on in the agenda before delegates split into multiple tracks. In each case it would be decided whether it was necessary to formulate a response, i.e. an outgoing LS, or take any other action.[79]For 5G, 3GPP had approved (in March 2016) a Study Item entitled “Study on NR New Radio Access Technology” (3GPP Tdoc RP-160671) which would involve studies within RAN Working Groups (WG) 1, 2, 3 and 4. Study items do not have the remit to develop Technical Specifications and are instead used (as a precursory step) to investigate the performance and feasibility of proposed techniques. The output of a Study Item typically takes the form of Technical Reports (TRs), which may further comprise conclusions and recommendations for next steps. The incorporation of new features into the 3GPP specifications requires the approval of a Work Item (which may or may not have been preceded by a corresponding Study Item) at a plenary meeting of the relevant Technical Specification Group (TSG).[80]For the physical layer component of the study (under the responsibility of RAN WG1), the Skilled Person would appreciate that, as for the other WGs, this would be guided by requirements set by the RAN plenary within a published Technical Report, TR 38.913 (at the Priority Date, the latest version of TR 38.913 was v14.1.0) “Study on Scenarios and Requirements for Next Generation Access Technologies” (and by the objectives of the Study Item description itself). They would further understand that output from RAN WG1 would be documented within a TR 38.802 “Study on New Radio (NR) Access Technology; Physical Layer Aspects”.[81]The Skilled Person would also understand that progress in developing the NR standard was being captured in the meeting minutes/reports of the meetings of the various 3GPP working groups (e.g., RAN1, RAN2 etc.). In order for the RAN1 group to make an agreement it would be necessary for the participating companies to reach a consensus, and in order to depart from an agreement it would also be necessary for a consensus to be achieved.[82]Delegates attending RAN1 meetings, and those following developments in RAN1 meetings in order to support the work of delegates, would use agreements and working assumptions from the meetings as an input to their work (although it is not agreed that such people represent the Skilled Person).[83]Because 3GPP’s efforts on 5G remained in a study phase at the Priority Date, books explaining or detailing its operation did not yet exist. There were, however, some precursory texts (including, for example, Chapters 23 and 24 of Dahlman, entitled “5G Wireless Access” and “New 5G Radio-Access Technology” respectively) that aimed to outline the general trends and directions in which cellular technology was evolving, to identify some of the key technology enablers and to set out guiding principles on which future systems should be based.

Radio Signals and Transmission of Information

[84]Radio Signals and Transmission of Information Information is transmitted via radio signals through a process known as modulation. This involves the modification of a so-called ‘carrier wave’ (a pure sinusoid at the desired radio frequency) with another signal containing the actual information or data that is to be conveyed. This results in a signal whose energy is concentrated around the carrier wave frequency, but with a degree of ‘spread’, typically to either side. The width of this spread is known as the ‘bandwidth’ of the signal and is, in-part, dependent upon the rate at which the information is transmitted (i.e. the amount of information that is conveyed per second). High data rate signals (where the information changes rapidly) tend to occupy a wider bandwidth around the carrier frequency than low data rate signals.[85]In radio communications systems, it is common to employ multiple carrier frequencies, with each carrying different information, as shown in Figure 1 below. In general, each carrier (for example, those labelled A to E in the figure) is transmitted on a particular carrier frequency, and has a particular bandwidth. A receiver communicating with a transmitter via a particular one of the carriers would typically employ a filter to extract only the carrier that is of interest to it. As shown in the figure, there may be a small degree of overlap between adjacent carriers due to the nonidealities of practical implementations (such as transmit power amplifier nonlinearities and imperfect channel filtering). Figure 1 - Carriers in a radio communications system[86]The property of the carrier wave that is modified varies depending on the type of modulation that is used. Such properties include for example: i) Amplitude (the size of the sinusoid) ii) Phase (the current position within its periodic cycle A full cycle is 360°, or 2π radians. ) iii) Frequency (the number of cycles per second)[87]Figure 2 shows simplified examples of these three types of modulation, for a scenario in which the information being carried is a series of binary bits: 0, 1, 0. For amplitude modulation, a ‘1’ is ‘larger’ than a ‘0’. For phase modulation, a ‘0’ does not affect the carrier wave whereas a ‘1’ inverts it (adjusts its phase by 180°). For frequency modulation, a ‘0’ is represented by a low frequency and a ‘1’ is represented by a higher frequency. Figure 2 - Types of Modulation[88]The duration in time over which the information being carried remains the same (and the associated properties of the carrier wave remain broadly constant) Though there may be some smoothing of the transition from one symbol to the next. is known as the symbol period. In the examples of Figure 2, three modulation symbols are transmitted, with each carrying one bit. Modulation schemes can also operate on groups of ‘m’ binary bits per symbol (for which there are Q = 2m different combinations - depending on the bit values). Each combination may be mapped to a corresponding one of Q possible modulation symbols.[89]Two commonly used modulation schemes in wireless communication systems (including those at the Priority Date) are Phase Shift Keying (PSK) and Quadrature Amplitude Modulation (QAM). PSK is a pure phase modulation scheme, whereas QAM combines both amplitude and phase modulation. Conceptually, these schemes involve the multiplication of the carrier wave with one of ‘Q’ complex numbers (determined by the corresponding group of ‘m’ bits) during a given symbol period The use of a complex number allows for both the amplitude and phase to be represented by a single value. . Each of the possible complex numbers for a symbol is referred to as a ‘constellation point’. Figure 3 shows the Q constellation points on the real (R) and imaginary (I) axes, for two variants of PSK (known as Binary Phase Shift Keying (BPSK) and Quadrature Phase Shift Keying (QPSK)), in addition to a variant of QAM using 16 points, known as 16-QAM. Figure 3 - Constellation points of common modulation schemes[90]In order to retrieve the transmitted information, a receiver must identify, for each symbol period, which of the Q constellation points was transmitted. This is the process of “demodulation” and is the means by which the receiver determines the set of ‘m’ bits that were carried by each modulation symbol.[91]The task of demodulation is made substantially more difficult however, due to the effects of the radio propagation environment through which the signal travels on its way from a transmitter to a receiver (the “radio propagation channel”). These have the potential to substantially alter the signal and therefore degrade the quality and reliability of the communication The receiver may wrongly interpret which modulation symbol was transmitted. .

The Radio Propagation Channel

[92]The Radio Propagation Channel Similar to sound waves and light waves, radio waves may be reflected or refracted by objects in the environment. As shown in Figure 4, a transmitted signal may reach a receiver via more than one path, each having a potentially different path length and therefore arriving at different times and with varying degrees of attenuation. At the receive antenna, the multiple delayed copies of the wanted signal are superimposed on top of one another and sum together in addition to any ‘interfering’ (unwanted) signals from other transmitters. The different path lengths are each associated with different phases, and as such, the signals arriving at the receiver have the potential to combine either constructively or destructively In general, two signals combine constructively when their phases are aligned, and destructively when they have opposing phases. . This situation may vary rapidly as a mobile receiver moves through the environment; a characteristic of the propagation channel that is known as ‘fast fading’ and which affects both amplitude and phase. At carrier frequencies that are typical of cellular systems (e.g. 2 GHz), these fluctuations occur at timescales of the order of one to a few milliseconds, depending on the speed of the mobile. The time duration over which the propagation channel remains largely unchanged is known as the coherence time Low coherence times are associated with high mobile speeds, and vice versa. . Figure 4 - Radio Propagation Environment[93]Both interference and noise can lead to transmitted radio signals being mixed up or lost, which is detrimental in a telecommunications system. A commonly used metric is the signal-to-noise ratio (“SNR”), which indicates the relative strength of the transmitted radio signal over background noise. At low SNRs, the signal information becomes harder to detect and this can lead to detection errors.[94]At a given instant in time, the propagation channel that exists between a transmitter and a receiver may be characterised by its ‘impulse response’ h(t). An impulse is a signal whose value is one at a time t = 0, but zero elsewhere. The impulse response is the complex-valued signal that would be received (in the time domain) if such an impulse was transmitted, and it thereby describes the various paths within the propagation channel, in terms of their different amplitudes, phases and times of arrival. By means of a simplified example, in the context of Figure 4, there are 3 constituent paths. The direct path will be the first to arrive, and is also likely, in this case, to be the strongest. There are then two reflected paths that follow a short time afterwards and which may be somewhat more attenuated, as they have been reflected and have travelled further. The ‘multi-path’ time-domain impulse response h(t) (for a given snapshot in time), may then look similar to the left-hand side of Figure 5 For ease of representation, although each path of the impulse response is complex-valued (a+ j.b), the figure shows only the corresponding magnitudes: |a + j.b| = √(a 2+ b 2). . The difference between the times of arrival of the first and last path, is known as the ‘delay spread’ of the channel Alternatively, the delay spread may be expressed as a root-mean-square (rms) value that takes into account the statistical variation of the impulse response over time (i.e. its long-term power distribution). . The same propagation channel may alternatively be represented in the frequency domain by means of its frequency response H(f) as shown on the right-hand side of Figure 5 Again, whilst H(f) is in-general, complex-valued, the figure shows only its magnitude. . The functions h(t) and H(f) are essentially two representations of the same thing (the propagation channel), and either of these may be directly derived from the other A Fourier transform converts h(t) to H(f). An inverse Fourier transform converts H(f) to h(t). . As can be seen, the presence of the multiple paths in time causes the channel to vary as a function of frequency The figure shows variations in amplitude, though the phase at each frequency may also be affected. . In general, the frequency response varies smoothly in that it remains broadly similar to itself within a ‘coherence bandwidth’ that is related to the delay spread in the time domain. Large delay spreads lead to narrow coherence bandwidths and vice versa. Figure 5 - Impulse response and frequency response of a propagation channel[95]The impulse response of the propagation channel is of importance in communications systems because it defines (for a given moment in time) how a signal that is input into the channel will be transformed at its output. More specifically, in the time-domain, the output signal may be calculated as a mathematical convolution (denoted ⊛) of the input signal with the impulse response. With z(t) representing any additive noise and interference, a received signal r(t) may then be expressed as a function of the transmitted signal s(t) as shown below in Figure 6(a).[96]It is also possible to model a similar system in the frequency domain, as shown in Figure 6(b), wherein each of the variables are represented by their frequency-domain counterparts. In this case, the convolution operation of the time domain is replaced with an element-by-element multiplication (denoted ⨀) Also known as a Hadamard product. . That is, in the frequency domain, the channel acts on each frequency of the input signal S(f) by multiplying it by the corresponding value of the channel response H(f). Figure 6 – Signal transmission over a propagation channel

OFDM Transmission and Reception

[97]Orthogonal Frequency Division Multiplexing (OFDM) is a method of transmission in which a series of ‘N’ modulation symbols are transmitted in parallel to one another, with each mapped to its own narrowband ‘sub-carrier’ (a complex sinusoid within a wider overall bandwidth of the carrier). Adjacent sub-carriers are separated by an amount that is referred to as the sub-carrier spacing, ∆sc. The overall bandwidth of the carrier (comprising N sub-carriers) is therefore, nominally, N × ∆sc.[98]Sub-carriers in OFDM overlap with one another in frequency because the sinusoids exist only within the finite time of each symbol period. This discontinuity of the time-domain waveforms translates to a dispersion of their energies in frequency. However, the sub-carrier spacing is arranged in such a way that despite this overlap, they do not interfere with one another (i.e. they are ‘orthogonal’). This property can be observed in Figure 7 below, where at the centre of each of the sub-carriers (labelled n-2 to n+2 in the figure), the contributions from all neighbouring sub-carriers is zero. Figure 7 - OFDM sub-carriers[99]Each of the N sub-carriers carries one modulation symbol within a period of time known as the OFDM symbol period, Tu. The sub-carriers are orthogonal to one another if the OFDM symbol time and the sub-carrier spacing are chosen such that: Tu = 1 / ∆sc (Equation 1)

Tu = 1 / ∆sc (Equation 1)

[100]This condition ensures that each sub-carrier has a different integer number of sinusoidal cycles within the symbol period Tu.[101]In general, data may be modulated onto each OFDM sub-carrier during a symbol period using a variety of modulation schemes, such as the BPSK, QPSK and 16-QAM techniques shown previously in Figure 3.[102]In practice, OFDM symbols include not only the symbol period itself (Tu), but also a ‘cyclic prefix’ (CP) part that is a copy of the last portion of the symbol. The CP is pre-pended to the OFDM symbol and has a duration of TCP, as shown in Figure 8 below. The CP is used to accommodate the multiple paths of the propagation channel It does so in two ways: i) by preventing the multi-path delays of the propagation channel from causing interference between successive OFDM symbols in time and ii) by creating a signal within the ‘main’ symbol period Tu that renders it suitable for reception using a Fourier transform. , and TCP is therefore typically selected in accordance with the expected delay spread of the environment in which the system is deployed. Figure 8 - Structure of an OFDM symbol[103]Because OFDM transmits information through the use of multiple parallel sub-carriers, its structure lends itself to implementation of the transmitter and receiver in the frequency domain, with efficient conversion to and from the time domain waveforms (that are actually transmitted and received) through the use of Fast Fourier Transforms (FFT) This is part of what motivates the use of OFDM. Equalization in the frequency domain is a simpler mathematical problem when compared to its time domain counterpart, and implementation complexity is thereby reduced. . A Fourier transform is a mathematical operation that converts a time domain signal to the frequency domain (and vice versa for an inverse Fourier transform). The ‘Fast’ versions of these transforms (the FFT and IFFT respectively) do the same, but via an algorithm that is more computationally efficient In particular for sequences whose length is an integer power of 2. .[104]This use of FFT’s and IFFT’s to implement OFDM is shown in a simplified form in Figure 9 below. In the transmitter, a block of n = 1…N modulation symbols S(n) in the frequency domain, are input to a size-N IFFT, which in-turn produces N time-domain samples. A CP is attached, and the resulting OFDM symbol is transmitted. The propagation channel affects each of the sub-carriers differently (according to the prevailing frequency response for the nth sub-carrier, H(n)), and each may be subject to additive noise and interference. At the receiver, the CP may be discarded and the N received time-domain samples are input to an FFT. This produces a set of complex values, R(n), which are representative of the received signals on each of the n = 1…N sub-carriers. Figure 9 - OFDM Transmitter and Receiver[105]The OFDM system may then be modelled as a parallel set of sub-carrier systems, wherein each may be described in the frequency-domain via: … in which, for the nth sub-carrier, S(n) is the transmitted modulation symbol, H(n) is the frequency response of the channel at the sub-carrier’s frequency and Z(n) represents any additional noise and interference experienced on that same sub-carrier. This is effectively a per-sub-carrier representation of the system shown in Figure 6(b). R(n) = S(n).

R(n) = S(n). H(n) + Z(n) (Equation 2)

(n) H(n) + Z(n) (Equation 2)

[106]Demodulation is then the process of determining from the received signal the most likely modulation symbol that was transmitted (and therefore also the series of ‘m’ bits with which it is associated). However, prior to doing so, the receiver must first ‘un-do’, as far as is possible, the effects that the propagation channel H(n) has imparted on the amplitude and phase of S(n); a process known as ‘equalisation’. The receiver does not have direct knowledge of the propagation channel, though it may estimate it through a process known as ‘channel estimation’. This is often facilitated by comparing a known ‘reference signal’ (that is inserted in some way into the transmission) with its received form, in order to determine an estimate of the complex channel value for each sub-carrier, denoted H^(n) . Nominally, this attempts to solve Equation 2 for a known S(n) (the reference signal) and an unknown H(n). The reference signal is typically predefined (and therefore known a-priori) to the receiver as part of the wireless system design or its specification. A reference signal that is used for the purposes of channel estimation is sometimes known as a “pilot signal”.[107]The type of signal used as a reference signal is usually chosen to have good autocorrelation properties, meaning zero or low correlation with itself at time offsets other than zero. When this is the case, the received signal and reference signal can be correlated and the output of the correlator will only depend on the effects of the propagational channel rather than the reference signal interfering with itself. The channel estimate can then be used by an equaliser to restore modulated symbols so they are no longer distorted.[108]The channel exhibits a degree of self-correlation in both time and frequency, and therefore changes relatively ‘smoothly’ in both of these dimensions A number of factors have a bearing on how rapidly the channel varies in time and frequency. For example, in the time domain, the rates of change increase with the speed of travel of the mobile, whereas in the frequency domain, the rates of change increase for channels with longer delay spreads. . As such, the reference signal need not be located on every sub-carrier in frequency or on every OFDM symbol in time. It may instead be located on a more-sparse subset of sub-carriers, and/or only on certain OFDM symbols in time. Interpolation (in both time and frequency) may then be used to derive an estimate of the channel on the intervening sub-carriers or OFDM symbols (that did not themselves contain a reference signal). Averaging (or filtering) of the channel estimates in time and/or frequency may be used to improve accuracy in the presence of noise, though this is typically only possible for sub-carriers that are separated by less than the coherence bandwidth, and for symbols that are separated by less than the coherence time of the channel. Beyond these limits, the sub-carriers may not be correlated with one another and combining is not then beneficial.[109]Once the channel estimates have been obtained, equalisation may then be performed. Simplistically, this could be achieved, for example, by dividing each R(n) by H^n. (In practice, R(n) may instead be multiplied by H^ *(n) / | H^ (n)|2, where * denotes complex conjugation. This gives the same result and avoids the need for a complex division.). This produces an estimate of the transmitted modulation symbol that is composed of the actual symbol itself, S(n), plus a noise term equal to Z(n) / H(n). However, the noise may be amplified (when the denominator of this term is small) and so other solutions are often employed that additionally take into account the Signal to Noise Ratio (SNR) when constructing the equaliser Such as so-called ‘Minimum Mean Squared Error’ (MMSE) approaches. .[110]These different processing steps within an OFDM receiver are shown in Figure 10 below. In this example, the set of received sub-carrier signal values R(n) (that are output from the FFT of the receiver), are first divided into those carrying Reference Signals (RS) and those carrying modulated data. Those carrying RS are input to the channel estimation process, which in-turn (using a local copy of the known RS) produces estimated channel values H^(n) for the data sub-carriers. These are used by the equaliser to derive estimates of the transmitted symbols, denoted S^(n) , which are subsequently demodulated to determine the bits that were transmitted The output from the demodulator may be a ‘hard’ decision (a 1 or a 0 for each bit) or a ‘soft’ decision reflecting the likelihood of each bit being a 1 versus a 0. . Figure 10 - Receiver processing in an OFDM system[111]In the scheme of Figure 10, the receiver uses knowledge of the phase of the propagation channel (obtained via the channel estimates) in order to equalise and demodulate the data, and this is known as ‘coherent’ demodulation. ‘Non-coherent’ demodulation schemes are also possible (which do not require or employ such knowledge) though these would not generally be used if the information itself is conveyed by means of phase Such as in BPSK, QPSK or QAM. .

Forward Error Correction (FEC)

[112]Forward Error Correction (FEC) Although the equalisation process in the receiver assists in compensating for the effects of the propagation channel, it cannot alone prevent bit errors in the communication (where the receiver misinterprets one or more of the transmitted modulation symbols). These may be caused by the presence of noise or interference, a loss of the signal due to fast fading, errors in channel estimation, and so forth.[113]FEC is a process that is used to protect a communication from errors. A series (or block) of ‘c’ information bits are expanded to create a longer series of ‘c+k’ coded bits. The additional bits add ‘redundancy’ and are calculated as a known function of the input bits. The redundancy provides robustness against potential transmission errors, in that the original message (of c bits) may still be decodable by the receiver even if some of the ‘c+k’ bits are lost or not received correctly. The ratio c/(c+k) is known as the FEC ‘coderate’. Low coderates (with more redundant bits) incur additional overhead but provide a high degree of robustness and are therefore suitable for poor or noisy radio conditions. Higher coderates (with fewer redundant bits) benefit from lower overhead but at the expense of reduced protection against errors, so are only suitable in good signal conditions. The FEC coderate may therefore be selected (or adapted) according to the required reliability and the current radio channel conditions.[114]Types of FEC encoding used in wireless communication systems include ‘block’ codes, ‘convolutional’ codes, ‘turbo’ codes and ‘Low Density Parity Check’ (LDPC) codes.[115]As shown in Figure 11, an FEC encoder is typically placed before the modulator in the transmitter, and a corresponding FEC decoder is placed after the demodulator in the receiver. Figure 11 - FEC encoding and decoding[116]Following FEC decoding, the receiver may also verify the integrity of the received bits by means of a Cyclic Redundancy Check (CRC). This is an error detection (as opposed to error correction) mechanism in which the transmitter computes a ‘checksum’ across a block of bits (prior to FEC encoding) and appends this to its transmission. The receiver calculates its own checksum across the block of received bits (after FEC decoding) and detects an error if the result does not match the checksum received from the transmitter.[117]The rate of misdetection is usually expressed as a proportion of erroneous instances of a given signal which are received relative to the total number sent, over a certain window. Common metrics include the Block Error Rate (“BLER”) or Frame Error Rate ("FER”). When specifying a tolerance for error in a particular engineering application, it would be typical to specify a target error rate at a given SNR, since errors become more prevalent when a signal is affected by noise.

Blind detection

[118]Blind detection The term ‘blind detection’ would also be known to the Skilled Person as a technique in wireless telecoms when a receiver tries multiple attempts to decode a received signal, without knowing certain parameters regarding its transmission, e.g. masking/scrambling ID, sequence, repetition level. The success or failure of each attempt is determined by an error detection mechanism (such as CRC).

Cellular Systems

[119]Cellular Systems Cellular systems allow for mobile wireless communications by means of a network comprising multiple base stations (BS). The base stations are distributed across the desired coverage area, with each serving one or more geographical regions (local to the base station) known as ‘cells’. As a mobile device moves within the region, the cell that is used to provide its connectivity may change.[120]Cell sizes vary depending on the location in which the BS is deployed. For example, an urban environment with more users and more physical obstructions such as buildings would favour a smaller cell size, whereas a rural environment with lower user density and more open spaces would favour a larger cell size. The Skilled Person would be aware that typical sizes in LTE could range between around 1km to over 100km. They would expect that whilst cells in NR may extend to similar sizes, they may be smaller than in LTE due to the proposed use of higher frequencies and the corresponding loss of coverage.[121]In 3GPP LTE, a base station is referred to as an ‘eNodeB’ (eNB) and a mobile device is referred to as ‘User Equipment’ (UE). At the Priority Date, a base station in NR was more formally referred to as a “gNB”. Figure 12 shows a simplistic example of an LTE cellular network, in which each of four eNBs communicate with UEs within the coverage areas of their respective cells. Figure 12 - Principle of a cellular network[122]Whilst Figure 12 shows only one omni-directional cell per eNB, in general eNBs may support multiple cells. For example, in a ‘tri-sectored’ configuration, an eNB may support three cells, with each spanning a different 120° segment of the circles that are shown.[123]The collection of eNBs is referred to as the Radio Access Network (RAN). As shown in Figure 13, the eNBs may be interconnected with one another (via an ‘X2’ interface) and with a Core Network (CN) via an ‘S1’ interface. The RAN is responsible for the allocation of radio resources within the system, the establishment, maintenance and release of radio connections and for mobility between cells. The CN comprises servers and gateways that manage aspects such as user authentication and security, and which provide onward connectivity to other networks. In 4G systems, the RAN is referred to as the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) and the CN is referred to as the Evolved Packet Core (EPC). Figure 13 – LTE Radio Access Network and Core Network[124]Communications from an eNB to a UE are said to occur in the ‘downlink’ (DL) direction, whereas those from a UE to an eNB are in the ‘uplink’ (UL) direction. In Frequency Division Duplex (FDD) systems, the uplink and downlink communications take place (potentially at the same time) on different carrier frequencies. Conversely, in Time Division Duplex (TDD) systems, the uplink and downlink communications take place on the same carrier frequency, but at different times. The LTE system supports both FDD and TDD modes of operation, with corresponding ‘frame structures’ An LTE ‘radio frame’ describes a 10ms time-domain structure, within which the different signals of the system are arranged. referred to as Type 1 and Type 2 respectively.[125]Radio communications typically use a layered architecture and multiple protocols arranged in a protocol stack. 3GPP’s UMTS and LTE standards both followed a similar approach with the physical layer (“PHY”) at the lowest layer, and higher layer protocols such as the Medium Access Control (“MAC”) protocol, Radio Link Control (“RLC”) protocol, and Packet Data Convergence Protocol (“PDCP”). The layered approach means that development of each layer can progress largely independently of the other layers.

Radio Resources

[126]Radio Resources In cellular systems, the overall ‘resource space’ (for example, of a carrier) is segmented into smaller units of resource that are typically defined in terms of time, frequency and (optionally) code The code dimension allows for multiple signals (transmitted at the same time and on the same frequency) to be distinguished from one another based on sequences known as codes. . These smaller units may then be assigned, within a cell, to particular signals, or used for the transmission of information to a given user.[127]In the OFDM system of LTE, a two-dimensional time-frequency ‘resource grid’ is defined, wherein each ‘Resource Element’ (RE) of the grid comprises one OFDM symbol in time and one sub-carrier in frequency. The sub-carrier spacing in LTE is defined to be 15 kHz, which (with reference to Equation 1), leads to an OFDM symbol time (excluding CP) of Tu = 66.67μs. The system supports two cyclic prefix lengths known as ‘normal’ and ‘extended’. For the normal CP length (~5μs), there are 7 OFDM symbols per 0.5 ms ‘slot’ and for the extended CP length (~17μs), there are 6 OFDM symbols per slot. Two slots form a larger time unit known as a ‘subframe’ (of duration 1 ms). A group of REs within one 0.5 ms slot and spanning 12 sub-carriers in frequency (180 kHz) is known as a Resource Block (RB). Figure 14 shows a pair of RBs within a 1 ms subframe of the LTE resource grid For a normal CP length. . Figure 14 - LTE Time-Frequency Resource Grid[128]LTE supports carrier bandwidths of 1.4, 3, 5, 10, 15 and 20 MHz, which correspond to 6, 15, 25, 50, 75 and 100 RBs respectively Leaving some frequency margin at the upper and lower edges of the carrier. . This is known as the ‘system bandwidth’ of a cell, and may be different for uplink and downlink carriers.[129]In a practical radio system the maximum transmission power is capped (usually due to a regulatory limit), so increasing the system bandwidth would distribute the available power amongst the subcarriers. This leads to a drop in the ‘power spectral density’ (measured in decibels per Hertz dB/Hz) and generally will make the signal on a given subcarrier less robust against noise. On the downlink, this may simply reduce the cell size, though this also depends on whether performance at the edge of the cell is ‘noise limited’ or ‘interference limited’.[130]The Skilled Person would understand that in NR specific REs, or groups of REs, would be allocated to different signals and channels according to their different bandwidth requirements.[131]In the time domain, a group of 10 consecutive subframes forms a radio ‘frame’ with duration 10 ms. A larger time unit comprising 1024 frames (10.24 seconds) is also defined and is known as a ‘multi-frame’. Each frame of the multi-frame is identified by its System Frame Number (SFN), from 0 to 1023. The SFN plays a crucial role in achieving timing alignment and allowing transmissions to be scheduled relative to a common time reference. The frame and multi-frame structures are shown in Figure 15 below. Figure 15 - LTE Frame and Multi-Frame Structure

Multiple Access

[132]The term ‘multiple access’ refers to the way in which the signals of multiple users may be multiplexed within a carrier of a cell. In 2G GSM Global System for Mobile communication. , Time Division Multiple Access (TDMA) is used to share a carrier amongst multiple users, by assigning each to different respective timeslots of a radio frame. In Frequency Division Multiple Access (FDMA) systems, different users may transmit at the same time, but with each using different frequencies. In Code Division Multiple Access (CDMA) systems, such as 3G UMTS Universal Mobile Telecommunications System. , multiple users may transmit at the same time and across the same carrier frequency, but using different ‘spreading’ codes that enable their separation at the receiver.[133]In LTE, Orthogonal Frequency Division Multiple Access (OFDMA) is used on the downlink as a means to divide the resources of a cell amongst its different users by assigning them to different RBs (on the same or different slots of a radio frame) within the overall resource grid. Thus, the multiple access scheme is principally a combination of FDMA and TDMA, with orthogonality in the frequency domain due to the use of the OFDM sub-carrier structure. The same is generally also true for the uplink of LTE, although formally, this uses a modified form of OFDM referred to as ‘Single Carrier Frequency Division Multiple Access’ (SC-FDMA) Or equivalently ‘Discrete Fourier Transform Spread OFDM’ (DFT-S-OFDM). .

Shared Channels and Scheduling

[134]Shared Channels and Scheduling A scheduler in the eNB is responsible for dynamically allocating radio resources within the cell amongst its users. In LTE, a control channel (known as the Physical Downlink Control Channel – PDCCH) may be used to inform a UE of an upcoming assignment or ‘grant’ of downlink or uplink resources in a subframe for the transmission of data. The data itself is then communicated (within the assigned resources) on channels known as the Physical Downlink Shared Channel (PDSCH) and the Physical Uplink Shared Channel (PUSCH). The PDSCH and PUSCH physical channels carry the downlink and uplink shared transport channels respectively, referred to as the DL-SCH and UL-SCH.[135]The PDCCH is located within a control region at the beginning of each downlink subframe The control region spans the full downlink system bandwidth and its duration in time may be varied on a per-subframe basis between 1 and 3 OFDM symbols (or between 2 and 4 symbols for narrow system bandwidths). . Other control channels also exist within the control region, including the Physical Hybrid ARQ Indicator Channel (PHICH) Which is used to carry acknowledgements that indicate to UEs whether their uplink shared channel transmissions were successfully received by the eNB (or not). and the Physical Control Format Indicator Channel (PCFICH) Which is used to indicate the duration of the control region in the current subframe. .[136]Downlink and uplink grants are sent within Downlink Control Information (DCI) messages on the PDCCH (or EPDCCH An Enhanced PDCCH, that was introduced for LTE as part of 3GPP Release 11. ) that may be addressed to a particular UE by means of a 16-bit Cell Radio Network Temporary Identifier (C-RNTI). A number of the 16-bit values are also reserved for special RNTIs, that are not UE-specific, and instead allow DCI messages to serve particular functions or purposes within the system.[137]The allocation of time and frequency resources (i.e., REs) to different channels involves trade-offs. Where it is necessary to allocate fixed resources to a channel, such as the Physical Broadcast Channel (PBCH) and PCFICH, this limits the number of resources that can carry user traffic. As such, these channels tend to occupy the REs necessary to carry minimal information to perform their functions. When allocating REs to these types of channels, the Skilled Person has to decide what information they need to carry, and what CRC allocation / code rate is necessary to achieve appropriate error detection / correction performance to meet a target BLER requirement at the cell edge.[138]As well as deciding the allocation of REs for fixed channels, it is necessary to consider where they should be placed in terms of symbol, slot and frame timings. If a channel with a certain number of REs occupies a single symbol then it will occupy a greater number of subcarriers (i.e., a wider bandwidth) than would be needed if it was split equally between two or more symbols.

Connectivity and Mobility in LTE

[139]Connectivity and Mobility in LTE Connectivity and mobility in LTE systems involve procedures at both the Core Network level and at the Radio Access Network level. When a UE is powered-on, it must register with (or ‘attach’ to) the Core Network in order to gain access to mobile services. Prior to this, UEs are in a ‘deregistered’ state and the network is unaware of their presence or location. Registration with the Core Network provides a ‘readiness’ to communicate, but the actual transfer of signalling or user data also requires a Radio Resource Control (RRC) connection to be established between the UE and a cell of the Radio Access Network. The existence (or not) of such a connection determines whether the UE is ‘RRC Connected’ or ‘RRC Idle’ (respectively).[140]Transitions from RRC Idle to RRC Connected may be initiated either by the UE or by the network, though in both cases, they are driven by the need to transfer data. Once the communication is complete, the RRC connection may be released and the UE reverts to RRC Idle to conserve network resources and reduce UE power consumption, until data activity resumes. However, the UE would typically remain registered with the Core Network (to avoid the need for a subsequent registration and to ensure it remains contactable should inbound data arrive).[141]As a UE travels throughout the network, its connectivity is adapted such that it is served by (usually proximal) cells that are able to offer the best service or signal levels. However, the way in which mobility is handled, differs according to whether the UE is in RRC Idle or RRC Connected. Mobility is UE-centric for RRC Idle, and network-controlled for RRC Connected.[142]RRC Idle: In RRC Idle, the UE determines an appropriate cell of the network on which to ‘camp’ via a process of cell selection and reselection. For initial cell selection, the UE identifies and measures signals in its vicinity and chooses a cell that is suitable. For cell reselection, the UE continues to assess the cell on which it is camped (in addition to neighbouring cells) and reselects to another cell if required. The network provides (via System Information that is broadcast within each cell) parameters that are used to control the UE’s cell selection and reselection behaviours. UE’s in RRC Idle keep the network informed as to their approximate location At a level of granularity known as a ‘Tracking Area’ (comprising a contiguous group of cells). and also maintain downlink synchronisation to the cell on which they are camped Synchronization is needed to perform signal measurements and to monitor the cell for potential ‘paging’ messages (which may, for example notify the UE of inbound communications). .[143]RRC Connected: In RRC Connected, mobility of the UE between cells is controlled by the eNB via a process known as ‘handover’. This is supported by downlink signal measurements (of the current serving cell and of neighbouring cells) which are reported by the UE to the eNB. The eNB controls what measurements are made, and under what conditions they are reported, via a measurement configuration that is sent to the UE. The eNB may then take these measurements into account (in addition to other factors) when deciding whether to instruct a handover of the ongoing RRC connection to a particular cell.

Connection Establishment and Random Access

[144]Connection Establishment and Random Access To establish an RRC connection, UEs (in RRC Idle) perform a Random Access procedure on the uplink carrier frequency of the cell on which they are camped. In the first step of the procedure, the UE transmits (on resources that are configured for random access) a ‘preamble’ sequence that is randomly selected from a defined set. Such transmissions are contention-based in that they are not coordinated or scheduled by the eNB. They therefore carry some risk of ‘collision’ (wherein two or more UEs select the same preamble and transmit on the same resources) To avoid this risk of collision (for example, during handover), LTE also supports a ‘contention-free’ random access procedure in which the eNB may assign, in advance, a ‘dedicated’ preamble sequence to the UE. However, for RRC connection establishment, the contention-based procedure is used. . If the preamble is detected, the eNB of the cell responds with a Random Access Response (RAR) and further uplink and downlink communications then take place (via the uplink and downlink shared channels) to establish and configure the RRC connection.[145]The Random Access procedure is also used in LTE to acquire or regain uplink time synchronisation Alignment of the UE’s uplink transmissions with those of other UEs arriving at the eNB receiver, in order to maintain orthogonality between their different sub-carriers. For this reason, uplink synchronization is required before any further uplink transmission (beyond the random access preamble) can be made. and in some cases, to request the allocation of uplink shared channel resources.

System Information

[146]System Information Cells of an LTE network broadcast System Information on a regular basis across the intended coverage area. This provides UEs with knowledge concerning the configuration of the cell (such that they may communicate with it properly) and parameters that control certain aspects of their operation. System Information is used for a wide variety of purposes, though some of its primary functions include the support of cell selection and facilitating initial access to the cell. For these reasons, the relevant parts of a cell’s System Information must be read by the UE at an early stage, before it attempts to access it.[147]The full set of System Information is segmented into a Master Information Block (MIB), plus a number of System Information Blocks (SIB1, SIB2, SIB3, … and so forth), with each SIB carrying parameters of a particular type or that share a common purpose within the system. In LTE, the MIB and SIB1 are transmitted with fixed periodicities (of 40ms and 80ms respectively), whereas the periodicities for the other SIBs are configurable (via SIB1).[148]System information in LTE is conveyed via a logical channel known as the Broadcast Control Channel (BCCH), which is mapped to one of two transport channels. The transport channel that is used to carry the MIB is the Broadcast Channel (BCH), which is in-turn, transmitted via the PBCH. The MIB carries some of the most basic (or essential) parameters that are required by the UE to receive the remainder of the system information. The MIB contains a total of 24 bits that comprise: The downlink system bandwidth (3 bits) The PHICH configuration This allows the UE not only to understand the configuration of the PHICH itself, but also the structure of the PDCCH (as both channels exist within the control region). Knowledge of the PDCCH structure is required to receive the SIBs. (3 bits) The 8 Most Significant Bits (MSBs) of the System Frame Number (SFN) The SFN ranges from 0 to 1023 and is therefore a 10-bit value. The 2 Least Significant Bits (LSBs) are not transmitted in the MIB and must instead be determined by the UE through a process of ‘blind decoding’ across different frame offsets of the 40ms PBCH cycle (that is, by detecting which of the 4 possible frame offsets results in a successful decoding operation). 10 spare bits[149]The SIBs are not carried on the BCH/PBCH, and are instead mapped to the DL-SCH transport channel, which is transmitted via the PDSCH. A special ‘System Information RNTI’ (SI-RNTI) This being one of the reserved 16-bit values to which a DCI may be addressed. is used within the corresponding DCI message on PDCCH to indicate that the DL-SCH transmission contains System Information.[150]SIBs are grouped into ‘SI messages’ according to their periodicity requirements. For each SI message, SIB1 defines a periodically-recurring time ‘window’ within which the transmission may occur. The specific time and frequency resources that are actually used (within the window) are under control of the downlink scheduler.

Cell Search

[151]Cell Search When powered-on, a UE must attempt to access a cell of the Radio Access Network in order to register with the Core Network. Before this can take place, the UE must first scan the frequency bands that it supports in order to identify a suitable cell within its locale (taking into account additional factors such as the networks that the cells belong to, their signal strengths, and the carrier frequencies and Radio Access Technologies Such as GSM (2G), UTRA (3G) and E-UTRA (4G). that they employ). This process also requires that the UE attains both time and frequency synchronization with the associated cells and reads their System Information.[152]These operations of ‘Cell Search’, ‘Cell Selection’ and ‘System Information Acquisition’ are closely coupled to one another and form an integral part of the overall initial access procedure Cell search is also used (beyond the stages of initial access) to identify, synchronise with, and measure neighbour cells for mobility purposes. . In the LTE system, they are supported by downlink signals known as the Primary Synchronisation Signal (PSS), the Secondary Synchronisation Signal (SSS) and by the PBCH.[153]Once the initial network configuration information had been received by a UE, the first signal that it could send to a base station in UMTS and LTE was a random access (“RACH”) preamble. The RACH preamble would be used to initiate a connection with the network. The process of cell search and the subsequent RACH request were collectively called ‘initial access’.

PSS, SSS and PBCH

[154]PSS, SSS and PBCH Cells of a particular LTE Radio Access Network are each associated with a Cell Identifier (cell ID). From a physical layer perspective, there are 504 cell IDs, which are divided into 168 groups of 3 cell IDs each. The physical layer cell ID is given by NIDcell = 3.NID(1) + NID(2), where NID(1) denotes the group (0…167) and NID(2) denotes the ID within the group (0,1,2). In a typical deployment, physical layer cell IDs are allocated to cells such that they are unique within their vicinity, and are only reused in distant cells. Other identifiers Such as eNB IDs and network IDs. are used (in combination with the physical layer cell ID) to uniquely identify a particular cell within a (nationwide) network or globally. The physical layer cell ID is conveyed by means of the PSS and SSS.[155]The cell ID is an important parameter to provide to the UE at the outset since it is used for scrambling subsequent signals that are detected by the UE. A UE is likely to be positioned so as to receive signals from multiple cells at the same time, since adjacent cells in LTE use the same frequency range. As such, it is important that it can distinguish between these to avoid interference.[156]The PSS and SSS are transmitted every 5ms (that is, twice every radio frame). Their symbol positions within the frame are different for the FDD and TDD frame structures, as is the spacing between them They are in adjacent symbols for FDD, but are 3 symbols apart for TDD. . To a lesser degree, the CP configuration (normal or extended) also affects the timings of the PSS and SSS. The configuration with a normal CP, and the locations of the PSS and SSS, are as shown below in Figure 16 (which is a simplified diagram and in particular does not show full detail in the frequency domain). For FDD, the PSS and SSS are shown with solid shading whilst for TDD they have diagonal shading. The figure also shows the PBCH, which is transmitted once per 10ms frame, alongside the first instance of the PSS/SSS In the same location for both FDD and TDD. . In the frequency domain the PSS, SSS and PBCH are all transmitted within the central 6 RBs (1.08 MHz) of the downlink system bandwidth, which allows cell search to be performed before this information is known. The PSS and SSS both occupy 63 sub-carriers (31 either side of the central unused DC sub-carrier), which is fewer than 6 RBs (or 72 sub-carriers). The PSS, SSS and PBCH are broadcast across the full coverage area of the cell. Figure 16 - Locations of PSS, SSS and PBCH in an LTE radio frame[157]The PSS is constructed using one of three different Zadoff-Chu (ZC) sequences These fall within a class of complex-valued ‘polyphase’ sequences with constant amplitude and which exhibit zero autocorrelation with cyclically-shifted versions of themselves (also referred to as ‘CAZAC’ sequences). These properties are also preserved if the sequence is transformed from the time domain to the frequency domain (or vice versa). The zero-autocorrelation property (in the time domain) enables accurate timing estimation whilst the constant amplitude property allows for transmission at higher average power (as it avoids the need for power ‘headroom’ to accommodate peak power excursions of the signal). of length 63, each having a different ‘root’ (a parameter used in the equation that generates them). The different roots With values 25, 29 and 34. provide low cross-correlation between the three PSS sequences, thereby making them more distinguishable from one another. Which sequence is used (from the set of three) is determined by NID(2) and the PSS therefore conveys this component of the cell ID. Additionally, the PSS is used by the UE to acquire initial time synchronisation with the cell (i.e., to the OFDM symbol boundary) and may also be used to provide coarse frequency synchronisation.[158]The SSS is formed by interleaving (in an odd/even fashion across sub-carriers) two constituent BPSK-modulated codes of length 31. These are formed using two different cyclic shifts of the same maximal-length sequence (M-sequence) These are pseudo-random binary sequences that are generated using a shift register of ‘n’ bits. The output sequence has a length of 2n-1 before repeating. . Additional scrambling operations are also applied, including sequences that are a function of NID(2). The PSS therefore provides the sequences for the UE to descramble the SSS. The pair of cyclic shifts is selected based on the cell ID group, NID(1), thereby conveying one of its 168 possible hypotheses. The odd/even mapping of the two cyclic shifts is alternated between the first and second transmissions of the SSS in a radio frame (spaced 5ms apart), thereby allowing the UE to disambiguate these two instances and determine the 10ms radio frame timing. As such the UE can identify the position of the frame boundary in order to align itself with the overall timing of the network.[159]The PBCH occupies 72 sub-carriers (6 RBs) within a group of 4 consecutive OFDM symbols, that are located in the second slot of the first subframe of each radio frame. Not all REs within this group are assigned to PBCH data transmission, as some are reserved to accommodate Cell-specific Reference Signals (CRS).[160]LTE supports CRS patterns That is, the pattern of REs (within the time-frequency resource grid) that are used for reference signals. for 1, 2 and 4 transmit antenna ports at the eNB. However, for PBCH, the REs reserved for CRS always correspond to the 4-port pattern Whose REs encompass both the 1-port and 2-port patterns. , irrespective of the actual number of transmit antennas employed at the eNB. Figure 17 shows an example of this pattern within an RB containing PBCH data (for the case of FDD). OFDM symbols, slots and subframes extend along the x-axis, and subcarriers are shown along the y-axis.

Figure 17 - PBCH and CRS REs within a frame

[161]Figure 17 - PBCH and CRS REs within a frame The REs in the subcarriers above and below the PSS and SSS, shown in black in the figure, are unused and serve as a guard band. The REs shown in red, and interspersed throughout the rest of the bandwidth are CRS locations.[162]The PSS and SSS each occupy blocks of 62 REs whilst the PBCH (with the interspersed reference signal, CRS) occupies a slightly larger block of 72 consecutive subcarriers. Like the CRS, the PBCH is scrambled using the cell ID in order to reduce inter-cell interference.[163]The PBCH carries network configuration information primarily as a payload of data that is defined by the layer 3 RRC protocol and known as the Master Information Block or “MIB”. The MIB allows the UE to obtain essential downlink information such as the downlink bandwidth, PHICH configuration and the 8 most significant bits of the SFN, which is 10 bits long in LTE. As mentioned above, the SFN is important for timing alignment as it tells the UE which radio frame the BS is currently transmitting.[164]Some further information is communicated via the PBCH but not carried explicitly in the MIB.[165]First, depending on the base station’s antenna port configuration, one of three masks is selected and applied to the MIB’s CRC to scramble this before it is broadcast to the UE. The UE applies the different candidate masks in turn to descramble the CRC, and can ascertain which of the antenna port configurations is being used from the mask that was able to successfully complete the check.[166]Second, since the 8 most significant bits of the SFN only change every 4 frames, the UE waits (for up to 40 ms) in order to determine the full SFN. In other words, once the SFN in the MIB has just changed in value from the SFN in the previous MIB, then the least significant bits for that frame are understood to be ‘00’, and for subsequent frames these least significant bits can be expected to cycle in turn through ‘01’, ‘10’, and ‘11’.[167]In both these cases, as Dr Wong pointed out, the information is indicated implicitly, rather than explicitly, to the UE. This results in the overall size of the MIB being a few bits shorter, which makes more efficient use of network resources.[168]Reference was made to this Fig. 17 during the cross-examination of Dr Wong on his evidence that claim 1 was obvious over LG 434, and attention was drawn to the following aspects, which it is convenient to note here: i) First, the PBCH comprises REs in four adjacent symbols, whereas the PSS and the SSS comprise only REs in a single symbol. ii) Second, the arrangement of the CRS in LTE is cell-wide in the repeated diamond pattern. For the purpose of finding a channel estimate from the CRS for use in decoding the PBCH, the CRS REs that would be used were not just the ones running through the middle of the PBCH, but those and the CRS running either side of the PBCH. The significance of the distinction is that the REs running through the middle of the PBCH are interleaved with the PBCH but the side REs are not.[169]For cases in which the eNB has more than one CRS transmit antenna port, the PBCH employs either a 2-port or a 4-port transmit diversity scheme As described at paragraph 187, transmit diversity involves the transmission of the same information from more than one transmit antenna. The information therefore arrives at the receiver via multiple (and preferably statistically-independent) propagation channels. The likelihood of errors due to fading may then be reduced. . These schemes are based on a technique known as Space-Frequency Block Coding (SFBC) For 2-ports, pure SFBC is used. For 4-ports, SFBC is combined with a technique known as Frequency Switched Transmit Diversity (FSTD). . The number of ports that are used for transmission of the PBCH at the eNB (one, two or four) is not explicitly signalled on the PBCH itself, and is instead determined blindly by the UE, through an attempted decoding of each possible configuration and determining which successfully passes CRC This process is further assisted by a ‘masking’ the PBCH CRC field with one of three different codes (for the one, two and four port cases respectively). In general, the CRC check will not pass unless the UE applies the same mask (code) as the eNB. .[170]The LTE PBCH employs a large amount of FEC encoding to ensure that it is robust and protected from errors. The information is encoded and transmitted over a ‘Transmission Time Interval’ (TTI) of 40ms However, due to the large amount of FEC encoding, the full 40ms TTI may not be needed for successful decoding, assuming the SNR is sufficient. . Figure 18 shows a simplified overview of the PBCH encoding, in which a 16-bit CRC is first appended to the 24 information bits of the MIB. The resulting 40 bits are then FEC encoded (via a combination of a 1/3-rate convolutional code and 16-times bit repetition) to produce 1920 channel coded bits (for normal CP) within a 40ms PBCH period As shown in Figure 17, 40 REs are available for PBCH data per RB. The PBCH uses QPSK modulation, and therefore, within a 40ms PBCH period, there are a total of 4frames × 6RBs × 40REs/RB × 2bits/symbol = 1920 bits available to carry the 24 information bits of the MIB. . The coded bits are then scrambled Scrambling is a bit-wise multiplication operation (binary exclusive-OR ‘XOR’) that randomizes the coded bits such that the message is less likely to be decodable by an unintended receiver. and QPSK-modulated prior to transmission. Figure 18 – Overview of PBCH Encoding in LTE

UE Processing for Initial Access

[171]Whilst the 3GPP standards define the structures of the PSS, SSS and PBCH, they do not prescribe the processing steps that are used by the UE to perform cell search, and these are largely left as a matter for UE implementation.[172]Tasks that the UE must perform include time and frequency synchronisation, detection of the cell-ID, determination of the CP duration and frame structure (FDD or TDD), measurement of the received signal power and reading of the cell’s system information.[173]These may be assisted by the PSS, SSS and PBCH, although the details of the processing are not standardised and thus may vary from device to device.

Time and Frequency Synchronisation

[174]Time and Frequency Synchronisation When a UE is powered-on or enters a new cell, it is neither time nor frequency synchronised to the downlink signals of the cell that it is trying to detect. To decode its system information, the UE must identify the OFDM symbol and slot timing and also the frame timing of the cell (i.e. the point in time, within a given 10ms window, at which the radio frame starts from the UE receiver’s perspective).[175]The UE must also align its reference carrier frequency with that of the network. UEs synthesise different carrier frequencies based on an internal reference local oscillator. These components exhibit some degree of frequency error due to manufacturing tolerances, UE temperature changes and so forth. However, a mismatch between the UE’s reference carrier frequency and the actual carrier frequency of the network results in a residual frequency offset in the received signal. This has the potential to degrade the reliability of communication and must therefore be corrected at an early stage.[176]Time and frequency synchronisation also provides the UE with knowledge regarding the time-frequency ‘position’ of the OFDM resource grid (which assists with the FFT-based frequency-domain processing that is characteristic of OFDM As described at paragraphs 103 and 104, and in Figure 9. ).[177]The PSS is typically used to acquire initial time synchronisation and to allow for coarse frequency correction. It also provides knowledge of the NID(2) component of the cell ID. A variety of processing techniques may be employed (in either the time domain or the frequency domain), though these generally involve computing correlations between the received signal and (time or frequency domain) replicas of the three possible PSS sequences. Peaks in the amplitudes of the correlations (potentially over several PSS observations) may be used to identify the presence and timing (within a 5ms period) of a PSS associated with a given value of NID(2).[178]The UE detects the symbol boundary and part of the cell ID by performing a sliding correlation between the UE’s own ZC sequence and the PSS. This has to be performed for each possible root sequence, which are referred to as ‘hypotheses’. Two different root sequences produce a low output, which means that generally the sliding correlation will only produce a peak if the hypothesis is correct, and this will be located at the symbol boundary (although other peaks may arise due to multi-path propagation).

Cell ID Detection

[179]Cell ID Detection Having achieved initial time and frequency synchronisation, processing of the SSS may then be performed in the frequency domain (following an FFT). The SSS is used not only to identify the cell ID group, NID(1) but also to resolve the 10ms radio frame timing. It may also be used to determine the frame structure type (FDD or TDD) and/or the CP duration (normal or extended), as the timing of the SSS, relative to PSS, varies for each of these configurations. Other techniques to accomplish these tasks are also possible.[180]Detection of the SSS sequences may be based on approaches that are either coherent or non-coherent. Coherent techniques utilise knowledge of the propagation channel, whereas non-coherent techniques do not (with some potential reduction in performance as a result). For coherent detection, the UE may use the detected PSS sequence as a reference signal in order to estimate the frequency response of the channel. This assumes that the channel remains largely unchanged between the SSS and PSS symbols, and that other cells (transmitting the same PSS) did not contribute substantially to the PSS that is observed Which may lead to differences between the estimated channel and the actual channel through which the SSS has passed. .

Received Signal Power Measurement

[181]Received Signal Power Measurement Knowledge of the cell ID (from the PSS and SSS), and of the radio frame timing, allows the UE to determine the RE locations of the CRS (within the time-frequency resource grid) and the sequences that they contain. The subcarrier offset of the CRS was given by 𝑣shift=𝑁𝐼D𝑐ell mod 6. By offsetting the subcarriers differently in neighbouring cells according to the cell ID, collision of reference signals in adjacent cells could be avoided thereby promoting better channel estimation of the various downlink channels.[182]Using the CRS, the UE may then perform Reference Signal Received Power (RSRP) measurements Or other associated measurements, such as Reference Signal Received Quality (RSRQ). , which are used for various purposes including for cell selection and reselection RSRP is also an important reporting quantity that is used for handover (when RRC Connected). For intra-frequency measurements (on the same carrier as the serving cell), the UE may synchronise to neighbouring cells and measure their RSRP, whilst also receiving signals from the serving cell. For inter-frequency measurements (on a different carrier frequency), the network may provide (if the UE requires them) ‘measurement gaps’ during which the UE is not scheduled on the serving cell, thereby allowing it to temporarily re-tune to another frequency in order to perform measurements. The need for measurement gaps depends on the UE’s capabilities (for example whether it has a dual receiver or not). . RSRP is a measure of the average received signal power of REs that contain CRS Based on the CRS REs for antenna port 0 (and optionally port 1). and may be obtained by suitably post-processing the corresponding channel estimates For example, by taking a linear average of their squared magnitudes. .

PBCH Decoding

[183]PBCH Decoding The PBCH is coherently demodulated using channel estimates that are obtained from the CRS. However, as described in footnote 39, whilst the UE has acquired 10ms frame timing (via the SSS), it does not yet know which frame (of four) corresponds to the beginning of the 40ms PBCH TTI. It also does not know how many transmit antennas are used at the eNB to transmit the PBCH (this affecting its transmission scheme).[184]The UE must therefore attempt to blindly decode the PBCH using various different hypotheses (for both frame offset and number of transmit antennas) in order to identify which combination passes CRC. Once the PBCH has been decoded, the UE has knowledge of the current SFN and also of the number of transmit antenna ports at the eNB. It may then use this information, in conjunction with the parameters conveyed by the MIB, to receive further system information within the SIBs, via the DL-SCH.[185]Multi-Antenna Operation To improve performance and/or reliability, wireless communications systems may employ multiple antennas at either the transmitter, the receiver, or both. For a transmitter with ‘T’ transmit antennas and a receiver with ‘R’ receive antennas, there are then T×R propagation channels over which the information may be sent. Figure 19 shows an example in which both T and R are equal to 2, thereby creating 4 channels (labelled h 1 to h 4). The use of multiple transmit and receive antennas is often employed in a technique known as Multiple Input Multiple Output (MIMO) operation. Figure 19 – An example of

Multi-Antenna Operation

[186]Antennas come in various physical forms that exhibit different characteristics such as their radiation patterns, polarisations, number of constituent antenna elements and so forth. In order to accommodate these various physical realisations, 3GPP technologies (such as LTE) define multi-antenna operation at a more abstract level by means of logical transmit antenna ‘ports’. Each port may be realised in practice by one or multiple physical transmit antennas, though it remains a single logical port from the receiver’s perspective. To receive a transmission that has been sent over a particular antenna port, the receiver does not require knowledge as to how the port has been implemented, but it does require an estimate of the ‘composite’ channel through which the signal has passed (this comprising not only the effects of the propagation environment, but also the effects of the one or more physical transmit antennas that are associated with that port).[187]Returning to Figure 19, the multiple propagation channels may be used in different ways. In the case that they are used to convey the same information as one another (for example, to improve the robustness and reliability of the communication), this is known as transmit diversity (where T>1), and/or receive diversity (where R>1).[188]Alternatively, the multiple propagation channels may be used to carry up to min(T,R) different ‘streams’ or ‘layers’ of information in parallel (a technique known as ‘spatial multiplexing’) The multiple layers may be used for a single UE (known as Single-User MIMO), or distributed amongst multiple UEs (known as Multi-User MIMO). . The transmissions take place over the same set of radio resources, and as such, the layers have the potential to interfere with one another. However, the different propagation channels over which they travel may be used to enable their separation via suitable processing (at the transmitter, at the receiver, or at both). In this way, the efficiency (or capacity) of the radio link may be improved. At the transmitter, each layer is mapped to one or more of the transmit antennas via a set of ‘precoding weights’ For each particular layer, there is one precoding weight per transmit antenna. The weights are complex-valued multipliers that are applied to the signal of a given layer prior to its transmission from a particular transmit antenna. . These may be fixed for a given scheme, or may be dynamically adapted according to the current channel characteristics For example, based on measurements or feedback from the UE. . Figure 20 shows an example of spatial multiplexing wherein two transmission layers are mapped to four transmit antennas, with each layer subject to a different set of four precoding weights. Figure 20 - Precoding of transmission layers[189]Multiple transmit and/or receive antennas may also be used to provide directional transmission or reception, via a technique known as ‘beamforming’. As is the case for spatial multiplexing, weights are again applied across a set of antennas, though in beamforming, the aim is to focus the energy of a layer in a given general direction, rather than to dynamically multiplex and separate multiple layers according to instantaneous channel conditions Combinations of beamforming and spatial multiplexing are however possible. . An illustration of this, where a sequence of narrow beams is typically used to sweep around the coverage of the base station, is shown in Figure 21 below. Taken from R1-165062, “Views on Beamforming with a Large Number of Antennas”, InterDigital Communications, RAN1 #85 (a document which is not itself part of the CGK) Figure 21 – Use of a sequence of beams to sweep around coverage of a base station[190]LTE supports these various multi-antenna transmission schemes via a defined set of ‘Transmission Modes’. For the downlink (PDSCH), there are ten Transmission Modes, which include single-port transmission and a number of schemes for transmit diversity, spatial multiplexing and beamforming. For the uplink (PUSCH), only two Transmission Modes are defined: single-port transmission and spatial multiplexing. Once a UE has established a connection to a cell, the eNB may configure the downlink and uplink Transmission Mode to be used (though this also depends on the particular capabilities of the UE and of the network).[191]The above Transmission Mode framework applies to transmissions that take place over the PDSCH and PUSCH. For the PBCH, this supports only single-antenna-port transmission, 2-port transmit diversity or 4-port transmit diversity (depending on the eNB’s transmit antenna configuration).

Reference Signals

[192]Reference Signals Reference Signals (RS) are used in wireless communication systems to support the process of channel estimation (for coherent demodulation purposes) at the receiver. RS may also be used for purposes other than demodulation, such as to enable measurements of signal strength or signal quality, or to provide knowledge of the channel characteristics to other processes that manage, adapt or control the radio transmissions.[193]In the downlink of LTE, there are two main types of RS that are provided for demodulation: Cell-specific Reference Signals (CRS) and UE-specific Demodulation Reference Signals (DMRS). One further type of RS is known as Channel-State Information Reference Signals (CSI-RS) are not used for demodulation, but are used to assist with some of the downlink multi-antenna transmission schemes There are further types of RS for the downlink in LTE, including those used for Enhanced PDCCH (EPDCCH), ‘MBSFN’ transmissions (from multiple cells at the same time), and ‘positioning’ (PRS). Uplink RS are also defined, for both demodulation (DMRS) and channel ‘sounding’ (SRS). .

Cell-specific Reference Signals (CRS)

[194]Cell-specific Reference Signals (CRS) CRS are, in general, present in every subframe and in all RBs of the downlink system bandwidth, irrespective of whether they are accompanied by data. They are transmitted across the cell coverage area. The CRS design supports eNB configurations with 1, 2 or 4 CRS antenna ports The CRS antenna ports are identified by port numbers 0, 1, 2 and 3. . For each port, the CRS occupy certain REs within the OFDM resource grid, arranged in a diamond-shaped lattice, and an example of these patterns (for the case of normal CP) is shown in Figure 22 The CRS pattern also shifts vertically (in frequency) as a function of cell-ID. The frequency shift is equal to (Cell-ID mod 6). . REs that contain CRS on one port are reserved (i.e. left ‘empty’) on the other ports, thereby ensuring that the CRS transmissions of different antenna ports do not interfere with one another. As can be seen from Figure 22, the nominal spacing between CRS REs on a given port is 6 sub-carriers. The diamond-shaped pattern allows the receiver to also estimate (on a different OFDM symbol) the frequency response of the channel halfway between these sub-carriers, which may assist with interpolation. The CRS REs carry a QPSK-modulated pseudo-random sequence that is a function of the cell ID and which varies across OFDM symbols and slots of a radio frame. Figure 22 - CRS RE patterns[195]Many of the ‘common’ As opposed to ‘dedicated’ or UE-specific. downlink channels of the LTE system (including PBCH, PDCCH, PHICH and so forth) are reliant upon CRS for their demodulation. Additionally, six of the ten PDSCH Transmission Modes also require them. CRS also serve as the basis for downlink signal strength and signal quality measurements in the cell, which are used for various purposes such as to control the mobility of UEs between different cells of the network.[196]CRS are transmitted from each antenna port in their ‘native’ form, in that they are not subject to the application of precoding weights. An implication of this, is that when a data transmission is subject to precoding (across multiple CRS ports), the ‘effective’ channel through which the data has passed differs from the channel through which the CRS have passed The effective channel for the data includes the precoder and the propagation channels associated with the multiple CRS ports, whereas the CRS are not precoded and each is transmitted from only a single port. . As such, the UE requires knowledge of the precoding weights that were applied, such that it can convert the native CRS channel estimates into equivalent precoded versions when receiving and demodulating the data In practice, the precoding weights are either fixed (and therefore known in advance) or signalled to the UE (known as ‘codebook-based precoding’, in which the weights are chosen from a predefined set of possible combinations). .

UE-specific Demodulation Reference Signals (DMRS)

[197]UE-specific Demodulation Reference Signals (DMRS) A number of the PDSCH Transmission Modes in LTE are based on the use of UE specific DMRS for demodulation purposes. These RS accompany a PDSCH data transmission in order to allow for its demodulation and are transmitted within the same subframes and bandwidth (RBs) as the data itself. They are also pre-coded in the same way as the data (they are associated with the same antenna port), which means that the channel estimates that are derived from them may be used directly by the UE for demodulation, without specific knowledge or signalling of the precoding that was applied at the transmitter This also means that the chosen antenna weights do not need to conform to a predefined ‘codebook’. . To support spatial multiplexing (of up to 8 layers), UE-specific DMRS may be provided for each layer of the transmission. In this case, each layer is associated with a different transmit antenna port Antenna ports numbered 5 and 7-14 are used for UE-specific DMRS. .[198]An example of the pattern of REs that are used for UE-specific DMRS (here for up to 8 layers using ports 7-14) A different RE pattern is used in the case of antenna port 5. is shown in Figure 23. Two groups of REs are defined, each supporting up to 4 ports. The RS of the ports sharing a group are Code Division Multiplexed (CDM) using orthogonal sequences Walsh Hadamard codes of length 2 or 4 are applied across REs of the same sub-carrier. (which allows for their separation at the receiver). Figure 23 – Example of UE-specific DMRS RE pattern

Channel State Information Reference Signals (CSI-RS)

[199]The CSI-RS framework within the LTE system is used as a means for UEs to assess downlink channel characteristics in multi-antenna environments. The corresponding measurements may be used to provide various forms of feedback to the network such that it may better control and adapt the downlink radio connection. The use of CSI-RS is often associated with multi-layer transmission modes that are based on UE-specific reference signals Such as transmissions modes 9 and 10 that support up to 8 layers. (for which, CRS may be unable to provide the required channel information).[200]Once a connection has been established, the eNB may configure a UE with CSI-RS resources to monitor The eNB may also provide the same configuration to other UEs, thereby allowing them to ‘share’ the same CSI-RS transmissions. . CSI-RS may be provided for up to 16 antenna ports (numbered 15 to 30). Depending on the configuration of the system, these ports may or may not have been subject to precoding In so-called ‘class A’ operation, the CSI-RS are assumed not to have been precoded (similar to CRS), whereas in ‘class B’ operation, the CSI-RS may be precoded (e.g. beamformed). .[201]The periodicity of CSI-RS transmissions is configurable (between 5 and 80ms), and when present in a subframe, they are transmitted in all RBs of the downlink system bandwidth. Because they are not required for demodulation, the pattern of REs that are occupied by CSI-RS can be sparse; for example, one RE per pair of RBs for each port.[202]5G Whilst efforts in 3GPP were ongoing to study and evaluate techniques for 5G, there were a number of founding principles that had become commonly accepted by the time of the Priority Date. Chapters 23 and 24 of Dahlman See paragraph 19. provide an overview of these principles and serve as reasonable basis for the CGK of the Skilled Person concerning 5G (though other sources would also have been available). The Skilled Person would also be aware of TR 38.913 and TR 38.802.[203]Next generation access technologies would need to support three primary usage scenarios, known as ‘enhanced Mobile BroadBand’ (eMBB), ‘massive Machine Type Communications’ (mMTC) and ‘Ultra Reliable Low Latency Communications’ (URLLC). These differ in terms of the connectivity attributes for which they are optimised. For example, eMBB targets high data rates for end-user internet access (particularly for multimedia applications such as high-resolution video streaming) whereas mMTC aims to support high connection densities for low complexity devices (e.g. IoT) and URLLC prioritises robustness and latency for demanding or safety-critical applications (for applications such as autonomous driving and remote surgery). Chapter 23 of Dahlman provides further description of these usage scenarios, in addition to their associated capability metrics (regarding, for example, data rates, spectrum efficiency, traffic capacity, latency, mobility and so forth).[204]There was also an understanding that the technology would need to be capable of addressing new spectrum As is also described in Chapter 23 of Dahlman. in order to meet the demands for capacity. It was expected that spectrum available to meet this need would be likely to lie in frequency ranges between 6 and 100 GHz These frequency ranges had been cited, for example, by the Radiocommunication sector of the International Telecommunications Union (ITU-R) in Recommendation M.2083 “IMT Vision – Framework and overall objectives of the future development of IMT for 2020 and beyond”, September 2015. , which is significantly higher than many of the traditional cellular bands (at approximately 2 GHz). Wavelengths in the mid to upper regions of this frequency range may be of the order of several millimetres, and their use is therefore often referred to as ‘mm-Wave’ communications.[205]At these higher frequencies, radio signals are more rapidly attenuated, and multi-antenna techniques such as beamforming may then be required to help overcome these effects, by using antenna arrays with a potentially large number of elements. Such arrays were also of interest as they offer the potential for higher system capacities through spatial multiplexing Sometimes referred to as ‘massive MIMO’. .[206]However, whilst issues concerning the size and practicality of such large-scale arrays were, to some extent, alleviated by the reduced wavelengths of the mm-Wave bands The antenna elements are often spaced half a wavelength apart, therefore the number of elements may scale with frequency, without increasing the overall size. , implementation challenges remained in terms of the associated Radio Frequency (RF) hardware. Such issues arise because, if the beamforming is carried out in the digital domain (before digital-to-analogue conversion), each antenna element requires its own RF transmit/receive chain. The need for multiple RF chains is removed if beamforming is carried out purely in the analogue domain, though this approach significantly reduces flexibility when compared to the fully digital approach. Between these extremes, a ‘hybrid’ beamforming architecture had emerged, combining aspects of both digital and analogue beamforming, in order that the number of RF chains remained manageable whilst also preserving some degree of flexibility.[207]As a result of the above, there was a common understanding that multi-antenna operation would serve as a key enabler in 5G, both to allow it to access spectrum in the mm-Wave region, and to deliver high capacity. Additionally, it was appreciated that the system may need to support a range of antenna architectures, including (but not limited to) digital, analogue and hybrid beamforming.[208]Multi-antenna transmission and beamforming sit amongst several other perceived key technology components for 5G that are mentioned in Dahlman (in Chapter 24 entitled “New 5G Radio-Access Technology”). These include, for example, a scalable OFDM ‘numerology’ (a set of OFDM design parameters, including the sub-carrier spacing, OFDM symbol length, slot length and cyclic prefix duration to address different frequency bands and use cases), flexible FDD and TDD Including ‘dynamic TDD’ wherein a slot or sub-frame may be dynamically assigned for either uplink or downlink use. duplex arrangements (to support both paired and unpaired spectrum), frame structures to enable low latency communications, multi-site connectivity and coordination, and methods relating to system access and the delivery of system information Similarly, sections 5.1 and 5.3 of TR 38.802 v1.1.0 also address duplexing, frame structure and numerology. .[209]The same chapter also suggests several guiding principles for the development of a 5G Radio Access Technology (RAT), to help ensure that the initial design does not unduly constrain its subsequent evolution in later releases (an aspect referred to as ‘forward compatibility’) Forward compatibility is also mentioned in section 5.2 of TR 38.802 v1.1.0. . These principles include an ‘Ultra-Lean Design’ (that attempts to minimise the need for ‘always-on’ transmissions), confining signals within prescribed time-frequency resources (referred to as the ‘stay-in-the-box’ principle) and the avoidance of strict timing relations (for example between a data transmission and its corresponding acknowledgement). These concepts therefore target a system that, from the outset, is sufficiently flexible and configurable to accommodate new features and improvements as they are added over time.[210]With regards to synchronisation signals and the broadcast channel, TR 38.802 v1.1.0 provides some description of these in section 6.2.3.1 (as part of a broader section 6.2.3 on ‘Initial access and mobility’). The text outlines that PSS, SSS and PBCH may be transmitted within an SS block (with one or multiple SS blocks composing a burst, and one or multiple bursts composing a burst set) and that, at least for the multi-beam case, the time index of an SS block is indicated to the UE.

The Motivation and Technical Objectives for New Radio

[211]The Motivation and Technical Objectives for New Radio At a high level, NR was intended to improve the speed and reliability, and reduce the latency, of cellular data transmission as compared to LTE and previous generations of radio communications. However, it was not expected to amount to a complete technological overhaul of LTE and, in the early stages of development of NR, LTE was treated as a starting point.[212]As mentioned above, a significant new development in NR was the proposed use of a wider frequency spectrum than LTE. This included the new >6 GHz frequency range intended to operate at mmWave frequencies, but the lower <6 GHz frequency band used in NR was also intended to be wider than the frequencies used in LTE. This heightened interest in the use of beamforming techniques, for the purposes of maintaining cell coverage even whilst operating at higher frequencies.

DISPUTED CGK

[213]DISPUTED CGK At the start of trial, the parties had identified one major issue, namely: 1. Would the skilled person’s CGK at the Priority Date include each of the agreements and working assumptions relating to 5G/NR cell search, initial access and mobility procedures in recorded in the minutes of RAN1 meetings? (Wong 1, §40; Anderson 2, §32)[214]The parties also identified two further issues, in respect of which Samsung said they may need to be determined, but ZTE said their determination was not necessary to decide this case. These were: 2. What would the skilled person understand by the term “implicit signalling”? (Wong 1, §122, 138, Anderson 2, §§28-29, 37) 3. Which version of TR 38.802 would form part of the skilled person’s CGK: v.1.1.0 or v1.2.0? (Anderson 2, §51, Wong 2, §17).[215]In so far as it matters, the second issue was not material. The experts agreed the Skilled Person would know of the term ‘implicit signalling’ but also that there was no formal definition of the term. Mr Anderson agreed that ‘the term was often used in 3GPP when referring to the communication of additional information by means of a characteristic of a signal or channel (that may communicate other information explicitly.’ As already mentioned, several examples were provided when the experts were discussing the CGK.[216]The first and third issues are intimately related. Both are concerned with the correct level of ‘focus’ of the Skilled Person.[217]Dr Wong’s Skilled Person would possess some additional CGK over that which was agreed between the parties, which I must now set out. I did not understand Mr Anderson to dispute the additional CGK which Dr Wong set out in his first report, although Mr Anderson did add a couple of minor points in his second report.[218]The additional CGK comprised information extracted from the minutes of various RAN1 meetings, comprising agreements and working assumptions from those meetings. The RAN1 meetings in question were specifically, the minutes of meetings #86, #86bis, #87, the 1st NR Ad Hoc, and #88. Samsung stressed that each set of minutes runs to over 100 pages, insofar as they relate to anything of interest. Specifically: Meeting Dates held Date of report Page count RAN 1 #86 22-26 August 2016 6 October 2016 154 RAN 1 #86bis 10-14 October 2016 10 November 2016 160 RAN 1 #87 14-18 November 2016 8 February 2017 157 RAN 1 NR Ad Hoc 16-20 January 2017 9 February 2017 106 RAN 1 #88 13-17 February 2017 23 February 2017 (in draft) 145[219]Samsung also stressed that Dr Wong’s Skilled Person has a deep working knowledge of everything that has been sufficiently worthy of minute as part of the CGK.[220]The additional CGK of Dr Wong’s Skilled Person. By way of background, Dr Wong pointed out that NR began to be discussed in RAN1 3GPP meetings during the RAN1 #84bis meeting in April 2016. It continued to be discussed at all subsequent RAN1 meetings throughout 2016 and up to the Priority Date.[221]Early discussions during the development of NR considered fundamental matters such as the waveform, multiple access scheme, frame structure and numerologies. For example, at RAN1 #84bis it was agreed that NR would support more than one subcarrier spacing and that multiple OFDM numerologies can apply to the same frequency range (i.e., subcarrier spacings could vary between channels). This reflected the approach in NR of introducing flexibility to use different subcarrier spacings for different signals in the same or different frequency ranges.[222]In RAN1 #85 it was agreed that 15 kHz would be the baseline design assumption for NR numerology, and other subcarrier spacings would be scaled by 2𝑛. At this stage it was also agreed that both multi-beam and single-beam based approaches should be studied for a range of procedures, including synchronisation / initial access signals.[223]Against that backdrop, in his first report, Dr Wong summarised what he characterised as the important developments with cell search and initial access, in the RAN1 meetings immediately preceding the Priority Date. He pointed out that developments at 3GPP meetings are fast-paced and these discussions took place around 8 years ago, so he did not recall all of the following in his initial discussions with Powell Gilbert about the CGK. However, he said he had refreshed his memory of the relevant meeting reports, and in his opinion the Skilled Person, as a physical layer specialist attending or following RAN1 meetings, would have been aware of the matters he set out as they would have been recent developments which had been agreed to form the basis of future work. At the very least, Dr Wong said the Skilled Person would have been aware of the matters set out below in general terms and would know they could look up any specific point of detail in the relevant meeting report.

RAN1 #86, August 2016

[224]RAN1 #86, August 2016 Initial access was first introduced as a distinct agenda item in RAN1 #86, as item 8.1.6 “Aspects related to initial access and mobility”. Tdocs submitted under this agenda item in RAN1 #86 were addressed to the basic principles for development of the initial access procedure and proposed areas for future study in initial access, and the following was agreed as the general way forward for further development in initial access:
“Agreements: • RAN1 should strive for a common framework, including for example structure of synchronization signals, for initial access • More specifically, especially within a group of frequency bands in the frequency range, RAN1 should strive for an unified framework covering • Note: In this context, NR cell corresponds one or multiple TRP(s) o Single beam based and multi-beam based deployments o TDD and FDD operations o Different/mixed numerologies o Standalone and non-standalone operations o Licensed band and unlicensed band operations o FFS: mMTC use case • RAN1 should take at least following requirements into account to design initial access o Providing at least following functionalities  Detection of NR cell and its ID o Initial time/frequency synchronization to the cell o Providing necessary information for random access o Providing sufficient number of the identity values to allow deployment flexibility o FFS: supporting efficient mobility o FFS: supporting efficient inter-RAT measurement o Reducing the frequency hypothesis UE needs to search for compared to LTE o FFS: detecting beam ID(s)”
[225]Dr Wong was of the view that the Skilled Person would understand this to be setting the key objectives and requirements for development of the initial access procedure in NR and, in particular, identifying some key parameters that would need to be communicated to the UE during that process (e.g., cell ID, time/frequency synchronisation information, necessary information for random access). He said that some of these requirements were well-established from LTE. However, as demonstrated by this agreement, the use of multi-beam deployment was also an important consideration, and this was new to initial access in NR. The concept of a ‘beam ID’ (the role of which, as I explain below, was subsequently fulfilled by the ‘SS block index’) was a new and important parameter in NR.[226]In relation to the time and frequency synchronisation requirement, the Skilled Person would understand that one or more synchronisation signals could be used to, first of all, allow the UE to find the frequency range used by the cell / network. A single synchronisation signal would allow a UE to get a rough timing synchronisation at the symbol level. It would also be necessary for a UE to fine tune both the frequency and timing to account for any mismatch between the UE’s internal clock and the network clock, and also any external channel effects, such as the Doppler effect. However, these corrections would need to take place continuously, and not just during initial access.[227]The Skilled Person would also understand that, before the UE could communicate with the BS in a random access procedure, in addition to achieving symbol level synchronisation, it would need to establish alignment with the frame, subframe and slot timings (sometimes known as frame boundary / slot boundary detection), although at this stage details of the frame structure and numerologies had not yet been agreed.[228]At this meeting it was also agreed that ‘at least one transmission bandwidth’ would be specified for transmission of each of the synchronization signal(s) and at least some essential system information. It was FFS whether the bandwidths of the synchronisation signals and the essential system information would be the same or not.

RAN1 #86bis, October 2016

[229]RAN1 #86bis, October 2016 A number of fundamental points were agreed at #86bis in relation to the synchronisation signals and PBCH. In RAN1 #86bis it was agreed that NR, like LTE, would use two types of synchronisation signal, the PSS and the SSS. The PSS would provide initial symbol boundary synchronisation, like LTE, and it was FFS whether the PSS would indicate part of the cell ID or would serve as a demodulation reference signal “DMRS” for the SSS, like LTE. It was agreed that the SSS would indicate at least part of the cell ID, like LTE. It was FFS whether it would provide other functionality, e.g. serving as a DMRS for the broadcast channel, facilitating RRM measurement, or deriving any timing indices.[230]Dr Wong had previously explained that the provision of the cell ID via the PSS and SSS would be understood by the Skilled Person as examples of implicit signalling. The Skilled Person would similarly recognise the provision of timing indices as another way that the SSS could be used for implicit signalling.[231]It was also agreed that NR would have at least one broadcast channel, called the PBCH, which would carry part, if not all, of the essential system information for initial access. It was further considered whether the PBCH would include the information necessary for the UE to identify the channel carrying the remaining essential system information, or not.[232]Dr Wong said that the working assumption was that the PSS, SSS, and PBCH would have a wider bandwidth than their counterparts in LTE, at least for subcarrier spacings that were greater than 15 kHz.[233]It was agreed that one subcarrier spacing for each of the PSS, SSS, and PBCH would be predefined in the specification for a given frequency range, but it was FFS whether the signals would have different subcarrier spacings to each other.[234]It was agreed at RAN1 #86bis that the PSS, SSS and/or PBCH should be transmitted together in an ‘SS block’. It was not yet agreed how they would be multiplexed or if there might be other signals within the SS block. It was also agreed that one or multiple SS blocks would compose an ‘SS burst’, and that one or multiple SS bursts would compose an ‘SS burst set’. The Skilled Person would understand that at least one of the purposes of the SS block was for beamforming the synchronisation signals: different SS blocks could be transmitted on different beams. The exact sequencing of bursts/burst sets was yet to be agreed, and some aspects would ultimately be left to implementers.[235]In addition, it was agreed that RAN1 should “Study [the] design of demodulation RS for broadcast channel, control channel and data channel” and study whether these should have a joint design, or be separate signals. At the same time, the following working assumptions were adopted in relation to the use of reference signals generally for beam management:
“Beam management procedures can utilize at least the following RS type(s): • Others are not precluded • Multiple UE may be configured with the same CSI-RS o RS defined for mobility purpose at least in connected mode  FFS: RS can be NR-SS or CSI-RS or newly designed RS o CSI-RS:  CSI-RS is UE-specifically configured  The signal structure for CSI-RS can be specifically optimized for the particular procedure  Note: CSI-RS can also be used for CSI acquisition o Other RS could also be considered for beam management such as DMRS and synchronization signals”
[236]At this stage it was appreciated that reference signals would play a useful role in beam management, i.e. allowing channel estimation for individual beams. The range of possible reference signals would be understood as covering all types of channels that could be used, including broadcast and user-specific ones.[237]The reference to “mobility purpose” in the first option in the list would be understood as relating to the ability for a UE to maintain a connection with the network (at least in RRC ‘connected’ mode) as it moved around, or in light of changing radio conditions. Such a ‘mobility RS’ would allow a UE to periodically determine the signal strength of different beams so that it could be switched over if necessary.

RAN1 #87, November 2016

[238]RAN1 #87, November 2016 At the beginning of the NR section of the #87 meeting report (see page 71, Exhibit SHW-5) it is noted that v1.0.0 of TR 38.802 was agreed and was intended to be presented at the next RAN plenary meeting. This TR would be understood as capturing the key points of agreement from the meeting reports in a more structured format, though it may not be as up-to-date as the meeting reports due to the lag in updating it.[239]By RAN1 #87 the use of a PSS and an SSS in NR was established and it was agreed that companies would begin to evaluate design parameters of the NR-PSS/SSS in preparation for the next meeting, such as their periodicity, subcarrier spacing, sequence length, sequence type, number of IDs provided and their resource mapping/multiplexing. Zadoff-Chu sequences and m-sequences were the two main sequences under consideration for both the PSS and the SSS at that time, although other options were not precluded.[240]It was agreed that, at least in a multi-beam case, the “time index of SS-block” would be indicated to the UE. The Skilled Person would understand that the ‘time index’ of the SS block was a way of identifying the chronological ordering of the block, including within a burst or burst set. The exact indexing method had not been agreed. This index was also called simply the ‘SS block index’. The association between the SS block index and beams was also widely understood by RAN1 #87 and at the Priority Date. It was intended that each SS block could be associated with a different beam (or each SS burst would be associated with a beam, depending on the indexing method), and this would allow the UE to notify the BS which beam it had received.[241]At this stage it had not been agreed whether an SS block index would need to be indicated to the UE in single-beam operation. If a base station used a single beam, e.g. an omni-directional one, and the SS block index was only used as a beam ID, then the SS block index might not be needed, since with a single SS block the UE is always served by the same beam in the cell, and a default and known location in time (slot and symbol) can be defined for this single SS block.[242]In terms of the PBCH, it was agreed that in the next meeting companies would report back on various design parameters including the payload size, the overhead of the PBCH including its DMRS, and what signal would be used for this purpose (e.g., PSS, SSS, dedicated DMRS or mobility RS), transmission scheme, periodicity and multiplexing in the SS block. The suitability of the PSS/SSS as a reference signal for the PBCH was under consideration.[243]At this stage a variety of options were being considered for a mobility RS in the context of inter-cell mobility. These included whether it was part of the SS block, or separate from it, and whether it used the PSS, SSS or the DMRS for the PBCH (if that was supported). It was also now being considered for IDLE mode as well as CONNECTED mode.[244]It was not yet agreed whether the PBCH in NR would carry all of the minimum system information needed for initial access, or whether this would be divided between the PBCH and another channel. The latter of these would have been similar to the division of system information in LTE, where system information was split between the MIB on the PBCH, and the SIBs on the PDSCH.[245]Assuming the latter of these options was taken forward, two alternative proposals were agreed to be considered regarding how the remaining minimum system information (i.e., that which was not communicated on the PBCH) would be communicated to the UE. The first was the use of an additional ‘secondary broadcast channel’ which may be a different design from the PBCH in terms of payload size, resource mapping periodicity etc. It was FFS whether this would be beam-specific, cell specific and/or TRP specific. The second was that the remaining information would be transmitted in a shared downlink channel. It was also FFS whether this would be UE-specific, UE group-specific, beam-specific, cell-specific, and/or TRP-specific.

RAN1 NR Ad-Hoc Meeting, January 2017

[246]RAN1 NR Ad-Hoc Meeting, January 2017 The RAN1 NR Ad-Hoc meeting in January 2017 was only for the purposes of addressing NR (see meeting report in Exhibit SHW-6). Initial access remained an important topic.[247]At this stage the signals comprising the SS block were finally close to being agreed, and were FFS between Alt 1: PSS, SSS and PBCH; and Alt 2: PSS, SSS, TSS and PBCH (where TSS would be a tertiary synchronisation signal). An accompanying note indicates that the possibility of multiplexing an MRS (Mobility Reference Signal) and/or data transmission in the SS block had not been excluded.[248]In relation to the MRS, the Skilled Person would understand from a separate agreement (in section 5.1.1.5 regarding the Mobility Procedure), that in IDLE mode, which is the relevant mode to consider during the initial access process, the MRS would either use a SS, or the DMRS for the PBCH (if supported), or both of these together. In other words, its role would likely be carried out by one of these signals, rather than by an additional signal.[249]The same set of agreements included a requirement that the UE should “be able to identify at least OFDM symbol index, slot index in a radio frame and radio frame number from an SS block”. This would allow the UE to be in full timing alignment with the BS. It was also agreed that the PSS/SSS would each carry part of the cell-ID.[250]It was agreed that the time index/indices of an SS block from which UE will derive the symbol, slot index in a radio frame (i.e., the SS block index, as described in [240] above) would be down-selected from two possible options. This built upon the agreement regarding the use of the SS block to achieve timing alignment, mentioned above in the preceding paragraph. Option(i) was a single index for every SS-block within an SS-burst set. Option(ii) involves two indices – one time index indicating each SS-block within an SS-burst, and an SS burst index indicating each SS burst within the SS-burst set. The previously agreed ‘SS block index’ was common to these options, and the second option split this into two smaller indices.[251]Possible mechanisms for indicating the SS block index were included with the same set of agreements. There were two approaches to using the PBCH, namely ‘implicit indication’ and ‘explicit indication’. The explicit mechanism would involve directly encoding the index/indices as channel data. The Skilled Person would consider the implicit mechanism to cover a broad range of implicit signalling mechanisms, e.g. using a CRC mask, as discussed at [165] above, or the ordering, locations, and hypotheses of any reference signals.[252]The third and fourth possible mechanisms would also involve implicit signalling, respectively via either an additional (tertiary) SS or the existing agreed SS (i.e. the PSS and/or SSS). Again, this would be understood to refer to similar sorts of implicit signalling options as above.[253]For initial cell selection, it was agreed that the UE would assume a default SS burst set periodicity which may be frequency band dependent, and that the UE could assume that a given SS block would be repeated with a SS burst set periodicity. A single set of possible SS block time locations would be specified per frequency band. The Skilled Person would be aware that, at higher frequencies, a greater number of beams would need to be supported due to higher propagation losses and the number of SS blocks would increase. It was FFS whether idle or connected UEs could be configured with additional information about which SS blocks in a SS burst set are transmitted (in other words, how many of the possible SS block locations would actually have a block transmitted in them).[254]It was agreed that the PBCH in NR would contain at least a part of the SFN. Again, this built upon the agreement mentioned above in [250] regarding achieving full timing alignment. It had also been the case in LTE, where the SFN had been carried on the MIB which was itself broadcast on the PBCH. As explained earlier at [163], the MIB is an RRC layer entity so it would have been possible for the SFN to be transmitted simply as bits on the PBCH in NR. The number of bits of the SFN and how much of the SFN would be indicated explicitly versus implicitly were FFS. The PBCH would contain a CRC which would provide some error detection. It was FFS whether the PBCH would contain a search space for the PDSCH, or secondary broadcast channel (depending on which was used) and it was FFS whether other parameters would be communicated on the PBCH.[255]It was agreed that there would be no blind detection of the NR-PBCH transmission scheme or number of antenna ports. This means that the transmission scheme would be fixed and the UE would know the number of ports in advance. Various transmission schemes were under discussion, including SFBC and precoder cycling.[256]SFBC would be understood as a reference to ‘space frequency block coding’ and is a transmission scheme for transmitter diversity: in effect, a stream of bits is distributed between physical antennas and transmitted over a range of subcarriers to make the transmission more robust against noise and environmental factors such as reflection, scattering and refraction.[257]Precoder cycling is another form of space-time coding. It involves applying a precoder (usually a complex number) which results in a phase and amplitude shift of the transmitted signal, the effect of which is similar to changing the transmission direction. By ‘cycling’ through the pre-coders, the transmission scheme is able to distribute the signal across different spatial directions of the propagation channel thereby providing diversity. This means on average, coverage across the cell is improved.[258]It was agreed that at RAN1 #88, the reference signal for PBCH demodulation would be down-selected from Alt.1: Synchronization Signal (e.g. NR-SSS); Alt.2: Self-contained DMRS; and Alt.3: MRS (mobility reference signal) multiplexed in an SS block, if MRS is supported in an SS block.[259]In anticipation of the RAN1 #88 meeting, and with a view to further refining the details of the initial access procedure, the NR Ad-Hoc meeting also invited companies to provide evaluation results based on agreed assumptions including a performance target of 1% BLER at –6dB SNR average received SNR. Companies were invited to specify exact values for a range of parameters including the PBCH payload (including CRC) and required number of REs, DMRS overhead assumption if used, number of OFDM symbols for PBCH and SS block in general, periodicity of PBCH, multiplexing of PBCH in SS block and subcarrier spacing. Companies were also invited to mention if the PBCH according to their design would “implicitly convey other information e.g. SS block timing”, which the Skilled Person would understand to refer to the SS block index.

RAN1 #88, February 2017

[260]RAN1 #88, February 2017 The RAN1 #88 meeting took place from 13 – 17 February in Athens, Greece, and therefore the Priority Date was only 7 days after it concluded. At the Priority Date, Dr Wong’s Skilled Person would naturally have been aware that the RAN1 #88 meeting had taken place, and would either have attended it in person, or have been monitoring its progress remotely. They would understand from the 3GPP FTP server that an initial draft of the meeting report had become available on the day prior to the Priority Date, i.e. 23 February 2017.[261]Dr Wong was of the view that, at the Priority Date, his Skilled Person would have been aware of the points of agreement and working assumptions that came out of RAN1 #88 and would have regarded them as a good basis for further action for the same reasons as those that had been made at earlier meetings. They would recognise that any future development of NR would need to take these into account.[262]At the start of the NR section in the RAN1 #88 meeting report it is noted that a new version of TR 38.802 had been agreed and endorsed during the course of that week, i.e. v1.2.0 in R1-1703622. This would therefore have also been seen as a useful consolidated source of agreements (subject to the slight lag in updating it to reflect the latest agreements from RAN1 #88).[263]While many points of agreement regarding initial access are noted in the meeting report (see Exhibit SHW-7), most of these relate to very specific implementation details. Dr Wong noted, however, that on page 57 working assumptions were adopted regarding the PSS and SSS together having about 1,000 hypotheses for indicating the cell ID, and also both having the same bandwidth as each other.[264]Further agreements on page 59 note that companies had been asked to study the minimum bandwidth for the eMBB and URLLC use cases, as well as a range of aspects e.g. frequency range SS transmission bandwidth, PBCH transmission bandwidth and SS block bandwidth. The Skilled Person would understand from the accompanying note that the RAN1 group was seeking to understand what constraints these use cases, and their minimum support bandwidths, might impose on generally on NR.[265]A further agreement was made on page 65 that the PBCH (including its CRC) would be between 40 – 100 bits in size.[266]In addition, the Skilled Person would be aware that it had been agreed that there would be a maximum number of SS blocks, L, within an SS burst set, and that this could vary depending on the frequency range that the BS was operating in. They would also know that it was proposed that SS blocks could be ‘activated’ or ‘deactivated’ (in other words, not transmitted) to allow the gNB to manage the beams and leave more resources in a frame to be used for transmitting data or control information, and the method for signalling to the UE which blocks were actually transmitted was still under discussion.[267]Analysis Two matters became clear to me from the level of detail and specificity in the various agreements made during this development process. The first is entirely obvious but should be stated: cell search and initial access involves complex technologies. Second, if Mr Anderson’s Skilled Person wanted to start on a building block, he or she would have a choice: either wait until the design of the cell search and initial access had been finalised in a TR or attend to the details which had already been agreed and the direction of travel of RAN1 on these topics. There was, it seems to me, no middle ground. Thus, Mr Anderson’s attempt, in his answer in cross-examination, to identify some middle ground does not really work. Again, the question which was not really addressed was where would Mr Anderson’s Skilled Person get his or her information from, from which to build or model some building block, other than the latest version of the TR, supplemented by subsequent RAN1 meeting reports.[268]I acknowledge Samsung’s general point that these details had to be picked out of longer documents, but this would have been relatively straightforward for the Skilled Person to do, bearing in mind his or her standard attributes. I also acknowledge the risk of being unfair to the Patentee in the focus on these details. However, it must have been the case that the real teams working in this area would have been locating and attending to these details, because they would present them (or, rather, their non-inventive counterparts) with the good basis for further action.[269]The final point I need to mention concerns some additional alleged CGK which was raised towards the end of the cross-examination of Mr Anderson. The backdrop to this was that Dr Wong had, as set out above, carefully addressed the RAN1 minutes and selected in his reports the matter which he considered would form part of his Skilled Person’s CGK and which was relevant to the matters before the Court (e.g. Wong 1/¶¶128-173). Mr Anderson, in reply, whilst not agreeing with Dr Wong as to the process, on the assumption that the minutes were being considered, identified further sections of the minutes which he considered would also be relevant (Anderson 2/¶¶33-52). Dr Wong agreed with those extra extracts (Wong 3/¶¶8 and 15).[270]However, towards the end of Mr Anderson’s cross-examination, long after Dr Wong had been released, a quite separate part of the minutes of RAN #88 [D2.2/7/p.651] was put to Mr Anderson as being relevant, [T3/345/24 onwards]. Perhaps unsurprisingly, Mr Anderson’s opinion as to what the minute was actually saying differed somewhat from that of the cross-examiner (see, for example, [T3/347/14-348/23] and [T3/354/2-24]).[271]Samsung objected, in a case of this complexity, to Counsel identifying somewhat Delphic new parts of CGK during cross-examination, especially cross-examination of the second expert. In this regard, Samsung relied on what Bacon J said recently in Merck KGaA v. Merck Sharp & Dohme and others [2025] EWHC 2376 (Ch) at [22] to the effect that it is not appropriate where there has been a carefully set-out expert process to simply start exploring some new case in cross-examination: ‘I was, however, not willing to permit the cross-examination of Dr Stec on the basis of evidence and analysis not discussed between the experts, nor considered previously by Dr Stec, nor explored with Mr Wynn in his oral evidence. Where there has been a lengthy expert report process, including a meeting of experts and a joint expert statement, the court is entitled to expect that the parties' cases, on the issues considered by the experts, will be presented on the basis of the evidence that emerges through the expert report process. As noted in my judgment in Cabo v MGA [2025] EWHC 1451 (Ch), §§49–50, the joint meeting of the experts provides an opportunity for the experts to revise their opinions as appropriate, and the court expects the experts to engage properly and objectively with the evidence of the other side. If an expert fails to do so, but then changes their position on a particular point during the course of cross-examination, the court must then determine the case having regard to that change of position. The party relying on that expert cannot expect the court to allow it to attempt to salvage its position by advancing an entirely new case at that stage, on the basis of an analysis that has not previously been considered by either of the experts in their reports.[272]Samsung argued that the same principles apply in a case such as this where there have been three expert reports from Dr Wong, and an interleaved expert process by which both sides have identified (from a substantial potential pool) the relevant matter said to be CGK upon which they rely, and a further process to carefully set out (in documents for the Court) what is agreed and what is disputed. In such circumstances, Samsung submitted, it is not appropriate for the second cross-examiner to seek to shore-up his client’s case by relying, without any notice, upon new material.[273]I agree with and uphold Samsung’s objection. However, I think this was an argument made just in case ZTE sought to rely on any of this in their closing. As far as I am aware, ZTE did not, so I need not say anything further.

THE PATENT

[274]THE PATENT It is convenient to examine the Patent at this point, partly in order to ascertain if its content provides clues as to the identity and attributes of the Skilled Person.[275]Mr Anderson provided a helpful summary, as follows, which I quote from his first report:
‘249. The patent describes various aspects that relate to the design and structure of Synchronisation Signal (SS) bursts and blocks in a forthcoming 5G NR system. The system will be required to support both a wide range of frequency bands and a diverse set of use cases and services, which in turn leads to a number of considerations for the SS design. These include the accommodation of different OFDM numerologies, the use of beamforming and beam sweeping for SS block transmissions and the existence of potentially different sub-carrier spacings for SS blocks and data. 250. In this context, the patent considers the time domain arrangement (or pattern) of SS blocks and bursts within a burst set, and the number of blocks (and beams) that may be supported for different carrier frequencies and numerologies. The positions of the SS blocks are also considered in relation to the data frame structure (which may use a different sub-carrier spacing to the SS transmissions). Alternatives are described wherein the SS block positions are either a function of the data sub-carrier spacing or are independent of it. 251. To accommodate beamforming and beam sweeping of SS block transmissions, the patent describes ways in which the indexes of SS blocks or bursts within the burst set may be indicated, including the use of DMRS to do so. In this context, it describes a number of different arrangements of the PSS, SSS, PBCH and DMRS within the time-frequency resource space of an SS block. The examples consider different bandwidths for the PSS, SSS and PBCH (and cases with either one or two PBCH symbols). 252. Other aspects that are addressed by the patent include the signalling of sub-carrier spacings and activated/deactivated SS blocks, and the use of tracking reference signals to provide fine time/frequency synchronisation.’
[276]The first heading in the Description is [Technical Field], where it is stated in [0001] (RS is defined in [0005] as meaning reference signal):
‘The present disclosure relates generally to wireless communication systems and, more specifically, to the RS multiplexing pattern and procedures to demodulate NR broadcast signals, along with the RS carried information.’
[277]Under the next heading of Background Art are some paragraphs discussing efforts to develop a 5G system and convergence with the Internet of Things technology. Much of this is repeated later and I can pick up the relevant parts then.[278]This section concludes with these two paragraphs: [0005] In a wireless communication network, a network access and a radio resource management (RRM) are enabled by physical layer synchronization signals and higher (MAC) layer procedures. In particular, a UE attempts to detect the presence of synchronization signals along with at least one cell identification (ID) for initial access. Once the UE is in the network and associated with a serving cell, the UE monitors several neighboring cells by attempting to detect their synchronization signals and/or measuring the associated cell-specific reference signals (RSs). [0006] The following publications are related to SS burst set: - SAMSUNG:
"SS BW and multiplexing", 3GPP DRAFT; R1-1700884; and - HUAWEI ET AL: "
Discussion on SS burst set composition and SS block time index indication", 3GPP DRAFT; R1-1703353.

[0006] The following publications are related to SS burst set:

[279]Two points arise from [0006]. This is the first mention of ‘SS burst set’ and the two documents referenced are Tdocs, even though neither expert said it was necessary to consult either of them.[280][0007], [0008] & [0009] state the ‘Technical Problem’, the ‘Solution’ and ‘Advantageous Effects of Invention’, respectively: [0007] For next generation cellular systems such as third generation partnership-new radio access or interface (3GPPNR), efficient and unified radio resource acquisition or tracking mechanism which works for various use cases such as enhanced mobile broadband (eMBB), ultra reliable low latency (URLLC), massive machine type communication (mMTC), each corresponding to a different coverage requirement and frequency bands with different propagation losses is desirable. Most likely designed with a different network and radio resource paradigm, seamless and low-latency RRM is also desirable. [0008] The present invention is set out in the independent claims whereas preferred embodiments and further implementations are outlined in the dependent claims, description and figures. [0009] Embodiments of the present disclosure provide an NR-SS burst set design in an advanced wireless communication system.[281]The numerous figures (1-28C) are then introduced, in the usual way, and in the descriptions of the figures we see various mentions of SSS/PSS/PBCH design in LTE and in NR, and NR-SS burst set composition, as well as SS block position. The main body of the specification follows, under the heading ‘[Mode for the Invention]’. It is only necessary to refer to a few of the paragraphs in this section which extend from [0012] to [0278].[282]I start with [0013] which lists a series of 3GPP TSs. It is apparent that the Patent assumes familiarity with these documents: in other words, the Patent assumes these are CGK:
‘[0013] The following documents and standards descriptions are relevant to the present disclosure: 3GPP TS 36.211 v13.2.0, "E-UTRA, Physical channels and modulation;" 3GPP TS 36.212 v13.2.0, "E-UTRA, Multiplexing and Channel coding;" 3GPP TS 36.213 v13.2.0, "E-UTRA, Physical Layer Procedures;" 3GPP TS 36.321 v13.2.0, "E-UTRA, Medium Access Control (MAC) protocol specification;" and 3GPP TS 36.331 v13.2.0, "E-UTRA, Radio Resource Control (RRC) protocol specification."’
[283][0014] makes it clear that 5G is a ‘post LTE system’ and [0015]-[0017] set out some ways in which 5G or NR will differ:
‘[0015] The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission coverage, the beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques and the like are discussed in 5G communication systems. [0016] In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul communication, moving network, cooperative communication, coordinated multi-points (CoMP) transmission and reception, interference mitigation and cancellation and the like. [0017] In the 5G system, hybrid frequency shift keying and quadrature amplitude modulation (FQAM) and sliding window superposition coding (SWSC) as an adaptive modulation and coding (AMC) technique, and filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.’
[284]The next few paragraphs, along with references to Figures 1-4B, describe some basic elements of a wireless network. In view of one issue regarding the construction of UE in claim 1, Samsung relied on [0022] which provides in relevant part:
‘Also, depending on the network type, the term "user equipment" or "UE" can refer to any component such as "mobile station," "subscriber station," "remote terminal," "wireless terminal," "receive point," or "user device." For the sake of convenience, the terms "user equipment" and "UE" are used in this patent document to refer to remote wireless equipment that wirelessly accesses a BS, whether the UE is a mobile device (such as a mobile telephone or smartphone) or is normally considered a stationary device (such as a desktop computer or vending machine).’
[285][0024] mentions that the various UEs illustrated ‘include circuitry, programming or a combination thereof, for efficient NR-SS burst set design in and advanced wireless communication system’.[286]I can pick up the disclosure at [0087], which repeats [0005] and [0007] and then continues (I pass over [0090] which simply introduces Fig 11): ‘Such goals pose at least the following problems in designing an access, radio resource, and mobility management framework. [0088] First, since NR is likely to support even more diversified network topology, the notion of cell can be redefined or replaced with another radio resource entity. As an example, for synchronous networks, one cell can be associated with a plurality of TRPs (transmit-receive points) similar to a COMP (coordinated multipoint transmission) scenario in LTE specification. In this case, seamless mobility is a desirable feature. [0089] Second, when large antenna arrays and beamforming are utilized, defining radio resource in terms of beams (although possibly termed differently) can be a natural approach. Given that numerous beamforming architectures can be utilized, an access, radio resource, and mobility management framework which accommodates various beamforming architectures (or, instead, agnostic to beamforming architecture) is desirable. [0091] For instance, the framework may be applicable for or agnostic to whether one beam is formed for one CSI-RS port (for instance, where a plurality of analog ports are connected to one digital port, and a plurality of widely separated digital ports are utilized) or one beam is formed by a plurality of CSI-RS ports. In addition, the framework may be applicable whether beam sweeping (as illustrated in FIGURE 11) is used or not. [0092] Third, different frequency bands and use cases impose different coverage limitations. For example, mmWave bands impose large propagation losses. Therefore, some form of coverage enhancement scheme is needed. Several candidates include beam sweeping (as shown in FIGURE 10), repetition, diversity, and/or multi-TRP transmission. For mMTC where transmission bandwidth is small, time-domain repetition is needed to ensure sufficient coverage.[287]I move onto Fig 12, on which some reliance was placed by ZTE, which illustrates an example beam sweeping operation, further described in [0097]-[0101]. Fig 12 looks like this:[288]ZTE were keen to stress that the Patent is only concerned with part of Fig 12, that in box 1210.[289][0100]-[0101] explain why there is a need for designing synchronisation signals and a primary broadcast channel which carries broadcast information (e.g. a master information block or MIB) in NR initial access and RRM.[290][0102] explains the term ‘numerology’: it ‘refers to a set of signal parameters which can include subframe duration, sub-carrier spacing, cyclic prefix length, transmission bandwidth, or any combination of these signal parameters.’[291][0103]-[0107] contain a summary of initial access in LTE. [0108] then explains that the NR’s carrier frequency as well as bandwidth is different and that:
‘For NR, the transmission bandwidth containing synchronization signals and PBCH is supposed to be larger than LTE. Moreover, the conventional periodic CRS may not be available as LTE. The NR requires new designs, as well as the corresponding transmission schemes.’
[292]The Patent then sets out certain points which it treats as already agreed in NR:
‘[0109] NR defines at least two types of synchronization signals; NR-PSS and NR-SSS. NR-PSS is defined at least for initial symbol boundary synchronization to the NR cell. NR-SSS is defined for detection of NR cell ID or at least part of NR cell ID. At least one broadcast channel (NR-PBCH) is defined. NR-PBCH is a non-scheduled broadcast channel carrying at least a part of minimum system information with fixed payload size and periodicity predefined in the specification depending on carrier frequency range. [0111] In an SS block, there are at least two types of synchronization signals: NR-PSS and NR-SSS. NR-PSS is defined for initial symbol boundary synchronization to the NR cell and NR-SSS is defined for detecting NR cell ID or at least part of cell ID. There are at most (N-2) NR-PBCH symbol(s) in a SS block. Also, the UE monitoring bandwidth for NR-PBCH decoding may be limited considering the complexity and power consumption in cell (re)selection procedure in IDLE mode. Same or slightly wider bandwidth compared with NR-PSS/SSS can be considered as baseline. [0112] FIGURE 13 illustrates an example SSS/PSS/PBCH in LTE 1300 according to embodiments of the present disclosure. The embodiment of the SSS/PSS/PBCH in LTE 1300 illustrated in FIGURE 13 is for illustration only. FIGURE 13 does not limit the scope of this disclosure to any particular implementation. Figure 14 illustrates an example multi-beam NR-PSS/SSS/PBCH 1400 according to embodiments of the present disclosure. [0115] The beam sweeping for multi-beam NR-PSS/SSS/PBCH is illustrated in FIGURE 14, where a SS burst set is consisting of multiple non-contiguous SS bursts and each SS burst include multiple SS blocks, which are located in consecutive symbols or slots. The SS burst set is used to carry out the beam sweeping over the whole cell coverage.’
[293]There are then many paragraphs and their associated figures which discuss some possible detailed exemplary embodiments.[294]I can pick up the specification at [0171] where Figs 18A and 18B are described as illustrating an example RS for demodulating the NR-PBCH according to embodiments of the present invention. These were the figures to which most reference was made at trial. Fig 18A looks like this:[295][0172] explains that the NR-DMRS can be time-domain multiplexed (the Patent uses the acronym TDM, which is also known as Time Division Multiplexed), as shown in 1801a and 1801b or interleaved frequency domain multiplexed (IFDM) within NR-PBCH symbols as shown in 1802a and 1802b (which are described as excluding guard band). These arrangements are further described in [0173]-[0177].[296]To explain further, each of the four block structures in Fig 18A comprise four consecutive OFDM symbols. In all four examples, the symbols carrying PSS, SSS and PBCH/DMRS span the same bandwidth and the PSS and SSS are TDM’d on the first and second symbols. Where the examples differ is the arrangement of the PBCH and DMRS in the third and fourth symbols: i) In 1801a, the PBCH is on the third OFDM symbol and the DMRS is on the fourth (and they are therefore TDM’d). ii) In 1801b, the PBCH and DMRS are TDM’d but the DMRS on the fourth symbol is mapped to only every other sub-carrier. iii) In 1802a, the PBCH spans the third and fourth symbols and the DMRS are inserted on the same two symbols by means of IFDM, but staggered as between the third and fourth symbols. iv) In 1802b, the PBCH and DMRS are again IFDM’d within both the third and fourth symbols, but the insertion pattern is the same for both symbols. v) The result is that the DMRS exist on different symbols to the PBCH for 1801a & b (TDM), whereas they are inserted on the same symbols as the PBCH for 1802a & b (IFDM).[297]Fig 18B looks like this and is described in [0178]-[0179]:[298]‘[0178] In one embodiment, as illustrated in 1803a of FIGURE 18B, there are three symbols in NR-SS block. The NR-PBCH symbol with inserted NR-DRMS REs has wider bandwidth than that of NR-PSS/SSS. The wider bandwidth provides more REs in the frequency domain for information delivery. The inserted NR-DMRS are used to achieve the CSI estimation over the wide BW. For example, if the NR-DMRS overhead is 1/3 REs within the NR-PBCH symbol, the BW can be extended to 1.5times of the sync BW to keep the similar NR-PBCH coding rate in case of no NR-DMRS. If the NR-DMRS overhead is 1/2 REs within the NR-PBCH symbol, the BW can be extended to 2times of the sync BW. [0179] In one embodiment, as illustrated in 1803b of FIGURE 18B, there are three symbols in NR-SS block. The NR-PBCH symbol with inserted NR-DRMS REs has same bandwidth as that of NR-PSS/SSS. Compared with two-symbol NR-PBCH, less REs are available for information delivery. The inserted NR-DMRS together with NR-SSS can be used to achieve the improved CSI estimation over the sync BW.’ A more specific illustration is given in [0187]:
‘[0187] In one embodiment, a long DMRS sequence mapping into the DMRS REs of two PBCH symbols and the DMRS sequence with length of 2*63 can use the interleaved two m-sequences with length of 63. For example, assuming 1/3 DMRS overhead, there are 85 DMRS REs in two PBCH symbols with 255 REs per symbol. The LDMRS-length sequences mapping every 3 subcarriers in two PBCH symbols, e.g., Zadoff-Chu sequences (LDMRS=83, or 79) or m-sequences (single sequence with LDMRS=63 or interleaved two m-sequences with length 31) can be used for indicating the SS block timing or part of the SS block timing, such as, SS block index per SS burst, and/or SS slot index per SS burst, and/or SS burst index if there are more than one SS burst. The DMRS sequences are used to identify different hypotheses and longer DMRS sequence length carry a larger number of hypotheses at the price of higher detection complexity at the UE side.’
[299]It is not necessary to set out Figs 19A-C, which illustrate the embodiments of TDM PSS/SSS/PBCH symbols, where the DMRS REs are inserted in PBCH symbols by using IFDM. In this context, it is explained in [0183] that the NR-SSS can be used for coherent detection of the DMRS sequences and the NR-PBCH demodulation is based on the CSI obtained by the NR-SSS together with the DMRS. Similar teaching is contained in [0190] by reference to Figs 20A-C.[300]Reliance was also placed on the first sentence of [0201], which covers various ways in which the RS can be conveyed, and this contains another mention of coherent detection in the specification: [0201] Also note that the NR-DMRS can also be termed as additional RS, additional SS, new SS, tertiary sync signal (TSS), extended SS (ESS), etc. Besides the RS based on the sequence design, the RS based on message coding can also be used to indicate the information for SS block timing. The message-based RS can use NR-SSS for coherent detection. Two codewords are used for NR-PBCH and message-based RS separately. The NR-PBCH/NR-DMRS TDM/IFDM multiplexing patterns illustrated in FIGURE 18A, 18B, 19A, 19B, 19C, 20A, 20B and 20C can be used to distribute the REs of the messaged-based RS in the bandwidth for PBCH symbol(s) to achieve frequency diversity. Also note that the location of NR-PSS and NR-SSS in FIGURE 19A, 19B, 19C, 20A, 20B, 20C, 21AA, 21AB, 21BA and 21BB can also be shifted as variation of the sub-embodiments.[301]The guard bands previously mentioned are described more specifically by reference to an embodiment shown in Figs 21AA, 21AB, 21BA and 21BB. It is unnecessary to set out these figures but they show various arrangements in which the NR-SSS has the same bandwidth as the NR-PBCH, with the NR-PSS smaller or the NR-PSS and NR-SSS having the same bandwidth smaller than the NR-PBCH. The arrangements in Figs 21AA and 21AB are more specifically described in [0204]-[0208]:
‘[0204] However, the NR-PBCH symbols with wider bandwidth provide more REs to include self-contained DMRS and sufficient remaining REs to send information MIB and other timing-related information, e.g., SS block index, burst index and/or the LSB of SFN (system frame number). The SFN is defined as the index of 10ms radio frames. The NR-SSS with same or similar bandwidth as that of NR-PBCH can be used to get the channel estimation for PBCH demodulation and the DMRS/TSS demodulation if NR-SSS and NR-PBCH as well as NR-DMRS use same transmission scheme on the same antenna port. [0205] For example, the NR-PSS bandwidth has 12RBs and the NR-PSS sequence with length of 127 is mapped onto consecutive 127 subcarriers of {-63,-62...-1, 0, 1,....62, 63}. The 144-127=17 subcarriers at the edges are reserved as the 11.8% guard band to avoid the interference from the data in case the data numerology is different from that of NS-PSS OFDM symbol. [0206] Regarding the NR-SSS bandwidth and NR-SSS sequence design, the following two sub-embodiments are illustrated. One sub-embodiment is shown in FIGURE 21AA and 21AB, where the NR-SSS bandwidth has 24RBs, larger than that of NR-PSS but same with that of NR-PBCH. And another sub-embodiment is shown in FIGURE 21BA and 21BB, where the NR-SSS bandwidth has 12RBs, similar to that of NR-PSS. [0207] In case of FIGURE 21AA and 21AB with NR-SSS with 24RBs, the NR-SSS sequence with length of 255 can be mapped onto the consecutive subcarriers of the 255 subcarriers (including DC) as {-127, -126, ...-1, 0, 1, 2, ..., 126, 127}. Another alternative is that the NR-SSS sequence with length of 127 is mapped onto the even or odd subcarriers of the 254 subcarriers as {-126, -124, ...-2, 0, 2, 4, ..., 124, 126} or {-125, -123, ...-1, 1, 3, ...125, 127}. The 288-254=34 subcarriers at the edges are reserved as the 11.8% guard band to avoid the interference from the data in case the data numerology is different from that of NS-SSS OFDM symbol.

(s) ’

[302]I must analyse claim 1 below, but reference was also made to claim 2, where the additional integer over the UE of claim 1 is:
‘wherein the processor (340) is further configured to determine an SSB burst index associated with the SSB based on a payload of the PBCH.’
General points made about the Patent.[303]Before I come to consider the Prior Art and ZTE’s arguments for invalidity, I should record some general submissions which each side made about the Patent, which I keep in mind.

Samsung’s submissions

[304]Samsung’s submissions First, Samsung submitted that the Patent was way ahead of any of the actual development in 3GPP which was only at the study item stage and that it provides the fundamental structure of the new SS Block to be used for initial access and mobility in 5G. The SS Block was a new concept in 5G, and it was common ground between the experts that, because of the differing requirements of 5G over 4G, a new approach was required. The problem which the Patent sets out to address is how to construct the SS Block for 5G.[305]Second, that by the admission of Essentiality, it is now common ground that the Patent and, more specifically, Claim 1 solves that problem. The resulting system decouples the previous fixed relationship between the PBCH and the PSS/SSS, allowing the PBCH to carry more information, to do so in a shorter period of time (fewer symbols), and to do so without the need for a cell-wide distributed reference signal (the CRS in LTE). This is achieved through the inclusion of the interleaved frequency division multiplexed DMRS specifically for demodulating the PBCH, but which also efficiently enables the indication to UEs of the SSB Index. Integrating the SSB Index feature into the DMRS conflicts with the primary purpose of the DMRS. It changes the fundamental nature of the DMRS from a self-standing reference signal (which requires no detection) to a signal which, for the optimum coherent detection, requires some other source of channel estimation.[306]Third, that consistent with the general approach of 3GPP, the Patent does not however mandate that coherent detection is utilised by the UE, allowing non-coherent detection (or some other means) to be utilised over the full scope of the claim. Consequently, so Samsung submitted, no issue of insufficiency/claim breadth is alleged or arises. However, as explained by Mr Anderson, the Patent provides substantial teaching (albeit by way of exemplary embodiments) as to methods taught by the Patentee which can be used within the scope of Claim 1 to enable reliable coherent detection to be based on the PSS/SSS even though those signals would be thought by those skilled in the art to occupy insufficient frequency bandwidth to provide a useful channel estimate for decoding the PBCH (see for example, Anderson XX [T3/248/23-254/11]; [T3/259/25-264/5]; and [T3/339/24-341/6]).[307]Fourth, that RAN1 (and 3GPP in general) ultimately adopted the Patent’s technique.[308]Fifth, that the collective efforts of RAN1, aware of all the prior art cited by ZTE (and much more) did not however alight upon it themselves before the Priority Date. Indeed, they got nowhere close. The study item for RAN1 closed (and was approved by RAN Plenary) a few weeks after the Priority Date, in the form of the V14.0 approval of TR 38.802. As confirmed by Dr Wong in cross-examination, that post-priority finished version of TR38.802 was the ‘output’ of the RAN1 study item [T2/89/4-5], and included none of the material aspects of Claim 1, vis: no wider PBCH bandwidth; no DMRS for the PBCH; nothing about how the SSB Index would be indicated; no IFDM’d DMRS and nothing about the DMRS having different sequences (see Wong XX [T2/195/17-198/4]).

ZTE’s submissions

[309]ZTE’s submissions For their part, ZTE stressed a series of points which went to their case on technical effect and the alleged lack of interaction. Their underlying point was that it cannot assist Samsung to suggest an interaction between claim features in some embodiments of claim 1. To assist Samsung, any interaction must arise in all embodiments of the claim. In this regard, ZTE relied on the decision of HHJ Birss (as he then was) in Environmental Recycling Technologies v Upcycle [2013] EWPCC 4 at [80], to the effect that any synergy relied upon must be possessed by everything falling within the claim. That is consistent with the general principle that the claim must be inventive across its full scope. I accept that general underlying point, which Samsung did not dispute.[310]First, ZTE stressed that the bandwidth feature is a relative one, rather than defining the absolute bandwidth of the PBCH. The bandwidth of the PBCH / DMRS has to be greater either than that of the PSS or that of the SSS (but need not be greater than both). ZTE took Samsung’s point that [0205] and [0207] treat the bandwidths of the PSS and SSS as including guard bands but pointed out that [0208] does likewise for the bandwidth of the PBCH. ZTE submitted that makes the bandwidth feature even more arbitrary (as they contended, if that were possible).[311]Second, ZTE submitted there is no magic in the term DMRS in the Patent. As cited above, the Patent makes it clear at [0201] that one can also call it an additional RS, additional SS, TSS etc., as Mr Anderson accepted: [T3 232/19–233/8].[312]Third, that claim 1 does not exclude the use of a further signal to assist with demodulation of the PBCH, and that further signal does not need to be IFDM’d with the PBCH (see Anderson [T3 234/12–236/4] wrt [0172] & [0190]).[313]Fourth, that claim 1 does not require a signal providing a channel estimate for coherent detection of the DMRS. The skilled person would have known that a signal such as the DMRS could be either coherently detected using a channel estimate or non-coherently detected, as the SSS could be in LTE. See Anderson [T3 236/15–237/15] and Wong [T2 178/9–179/8].

CLAIM 1

[314]CLAIM 1 The parties divided claim 1 into the following integers (with the identifying numerals omitted):a. A. A user equipment, UE, in a wireless communication system, the UE comprising:b. B. receive, from a base station, BS, a synchronization signal block, SSB corresponding to an SSB index, the SSB including a primary synchronization signal, PSS, a secondary synchronization signal, SSS and a physical broadcast channel, PBCH,c. C. carrying a master information block, MIB, with a demodulation reference signal, DMRS, for demodulating the PBCH, wherein PBCH resource elements, REs, and DMRS REs are interleaved frequency-domain multiplexed, IFDMed, and the PBCH and the DMRS for demodulating the PBCH have wider bandwidth than a bandwidth of the PSS or the SSS; andd. D. identify at least full or partial SSB index based on a sequence of the DMRS. a transceiver; a processor coupled with the transceiver and configured to:

Issues of construction

[315]Samsung identified two issues of construction concerning the following expressions: i) First, ‘user equipment, UE’; and ii) Second, “the PBCH and the DMRS for demodulating the PBCH have wider bandwidth than a bandwidth of the PSS or the SSS”. iii) There is also a third issue, concerning the meaning of the DMRS.

User equipment UE

[316]At trial, it was confirmed there was no dispute on construction – the meaning is clear from [0022], quoted above in [284]. Samsung’s point went to obviousness and the required end point: i.e. how far does the skilled person’s obvious developments have to go in order to render this product claim invalid? Samsung accepted that a solid design for the requisite part of a product would, in general, suffice, but they argued that, in the present case, Dr Wong’s ‘best case’ is nothing more than a tentative concept that would be insufficiently supported to even be a submittable proposal to RAN1; still less that it was a solid design for the material part of a UE. This is a point I return to later.[317]‘the PBCH and the DMRS for demodulating the PBCH have wider bandwidth than a bandwidth of the PSS or the SSS’ There was no dispute that this bandwidth feature is a relative one. Apart from that, any dispute evaporated at trial, after a bit of manoeuvring. The dispute, such as it was, concerned the meaning of ‘bandwidth’ in this phrase. Samsung’s point was that the bandwidth of the PSS and SSS in the claim includes any associated guard bands, as is apparent from [0205] and [0207]. In other words, the bandwidth is the ‘nominal’ bandwidth and not the ‘occupied’ bandwidth (to use Mr Anderson’s terminology, which Dr Wong adopted in XX [T2/73/4-18].[318]The background to this point was that, in LTE, associated “guard bands” are present at the outer edges of the PSS and SSS but not the PBCH – see Figure 17 in the Patent for example and Figure 6.10 of Cox [CXX-SHW/6/162]. The guard bands do not carry sequence data of the PSS/SSS but are intimately related to the successful detection of the PSS/SSS during initial access (as Dr Wong made clear in XX at [T2/72/23-73/3]). Samsung argued that this means that the ‘occupied bandwidth’ of the PSS and SSS is slightly smaller than the ‘occupied bandwidth’ of the PBCH, but that all three however have the same ‘nominal bandwidth’.[319]ZTE took the point regarding [0205] and [0207] but pointed out that [0208] raises the possibility of using guard bands for the PBCH, unlike in LTE. ZTE therefore argued in opening that the bandwidth of the PBCH/DMRS IFDM’d structure should likewise be the ‘nominal’ bandwidth and include any associated guard bands, [T1/27/23-28/15]. Samsung agreed.[320]However, ZTE sought also to argue that the position on the PBCH/DMRS fed into its concerns about the alleged arbitrary nature of the relative bandwidth issue [T1/28/16-30/8]. Samsung’s retort was that it made no difference at all: a wider nominal bandwidth for the PBCH is still materially different to the nominal bandwidth being constrained to be the same as or narrower than that of the PSS/SSS. This is a point to which I return when I consider ZTE’s arguments on technical effect.[321]‘DMRS’ The meaning of the DMRS in the claim is easily resolved. It is not a pure reference signal. Instead, it must carry sequences, including (i) a sequence for demodulation of the PBCH but also (ii) sequences to indicate the SS block index. I discuss the detail of these arguments under the Collocation / Interaction heading, below.

THE PRIOR ART

[322]THE PRIOR ART By way of introduction, in closing ZTE’s case of invalidity was largely founded on the disclosure of LG 434: i) ZTE’s primary case was that claim 1 of the Patent was obvious in the light of LG 434. ii) ZTE’s back-up case of obviousness was based on its collocation argument, which split claim 1 into two parts, with LG 438 being used to attack the first part of the claim and LG 434 for the remainder. iii) ZTE’s third attack was alleged lack of technical contribution of aspects of claim 1, again based on LG4 34 but also on aspects of the CGK.[323]It was common ground that ZTE’s primary case requires a mosaic of LG 434 with an extract from the final NR Ad Hoc Meeting minutes. Before discussing these arguments further, I must analyse what LG 434 disclosed to the Skilled Person at the Priority Date and make some observations about LG 438.

LG 434 - Disclosure

[324]LG 434 - Disclosure LG 434 is a TDoc submitted on 7th February 2017 for the RAN1 #88 meeting on 13th-17th February 2017 (i.e. the meeting just before the Priority Date). It is entitled “Discussion on SS burst set composition and time index indication”. It was agreed that the skilled person would be familiar with the concepts of SS burst sets, SS blocks and the SS block index from their CGK.[325]Before I describe the details of the disclosure, I record that both experts agreed that LG 434 is a document addressed to Dr Wong’s Skilled Person rather than Mr Anderson’s, who would wait for the “consolidated and formalised content of 3GPP’s TRs and TSs” (Anderson 2 §10). There were some mini-disputes over the disclosure of LG 434 which I resolve below. LG 434 is not written in perfect English, but, save for one specific point which I discuss below, the meaning is clear enough.[326]In the introduction, LG 434 begins by citing agreements from the NR Ad-Hoc meeting Chairman’s note. Chairman’s notes are draft meeting reports and were published on the 3GPP server (Wong 1 §51). It was common ground that a Chairman’s note would be similar to the final meeting report (Anderson 1 §301) which would be published before the next meeting. The final report would be the version the skilled person would refer to, if it was available (Wong 1 §52). The final report of the NR Ad-Hoc meeting had been published by the Priority Date.[327]The first bullet point of agreements relates to two alternative indexing methods for the “time index/indices of an SS block”. It was common ground that this is referring to what claim 1 calls the SSB index. It records that the indexing method is to be chosen from either a single index (i.e., one index for every block in a burst set) or multiple indices (i.e., one index for every block in a burst, and another for every burst in a burst set).[328]The second bullet point relates to possible mechanisms by which the index will be indicated to the UE. There are four specific options listed:(i) implicit indication by PBCH;(ii) explicit indication by PBCH;(iii) indication by an additional SS, if such an additional SS is introduced; and(iv) indication by NR-SS. The fifth bullet notes that this does not preclude other mechanisms.[329]LG 434 then has two sections of technical discussion, each relating to a different proposal for the composition of the SS burst set and the indication of the SS block index.[330]The first section discusses the “SS burst set composition”, by reference to two alternative ways of sending SS blocks and bursts, called the ‘localised’ and ‘distributed’ types. These two types are shown in Figure 1 of LG 434. The discussion is brief and not material. It relates to putting the UE into IDLE mode between receiving SS bursts, which could allow the UE to save power. LG 434 recommends the localised type in its proposal 1.[331]The second section is directed to “time index indication” and addresses the two bullet points in the agreements from the RAN1 NR Ad-Hoc meeting in the introduction.[332]First, LG 434 discusses the alternative single index (Alt 1: one time index for every SS-block within an SS burst set) and multiple index (Alt 2: a combination of SS burst index and SS block index) indication methods. It states that if the single index method is supported “large number of bits is necessity to express the all possible number of SS-block within SS burst set periodicity” and that “In this case, explicit indication by PBCH is preferable if PBCH can contain enough bit size”. Alternatively, the multiple index method could be used, allowing some of the bits to be sent on the PBCH and some to be sent on a different channel for flexibility (as the experts agreed: see Wong 1 §197, Anderson 1 §296). An example is given whereby if the PBCH payload cannot contain enough bits, the SSS or additional signal (if defined) could be used (Wong 1 §198, Anderson 1 §296). The Skilled Person would think that these were sensible options to consider (Wong 1 §198).[333]LG 434 says that if the SSS were to be used, the SSS sequence would need to be extended to provide additional hypotheses ‘for delivering SS block index’. That statement is followed by a second sentence which the experts agreed was not easy to understand. It reads:
‘However, this sequence is not preferable because SS block indication is necessity as a single purpose only in multi-beam case.’
[334]Mr Anderson suggested that it could be read as saying that indication of the SS block index was only needed in the multi-beam case, but he also explained that the Skilled Person would appreciate that it would likely be necessary to signal the SS block index in the single-beam case – [T3 227/20–228/18 & 283/10–284/3]; Dr Wong agreed [T2 103/6-19 & 104/16-23]. In any event, it was not suggested that this affected the message that the skilled person would take from LG 434.[335]LG 434 goes on to state that, on the other hand, if an additional signal is introduced this could be used ‘for multiple purpose’ in a single or multi-beam case. The example given is that it could be used for PBCH demodulation in both the single and multi-beam cases, and for SS block indication in the multi-beam case (Wong 1 §201, Anderson 1 §297). This is captured in proposal 2 of LG 434, which states:
“NR should consider that if additional signal is introduced for SS block indication, this signal is used for multiple purpose (e.g. PBCH demodulation, SS block indication).”
[336]Dr Wong considered that because the proposed signal is said to be “for PBCH demodulation”, the Skilled Person would understand it to be referring to a reference signal suitable for channel estimation (Wong 1 §201). Dr Wong explained (Wong 1 §203) that the proposal to use a signal for both SS block indication and a reference signal would seem sensible, as the skilled person would know that they would need a reference signal for PBCH demodulation in any event, and that there would be types of signals that would be suitable for both channel estimation and indicating information (e.g. a suitable sequence generated by using the SS block index as a root).[337]I should address two minor points and one with more significance. First, Mr Anderson made a point that proposal 2 was about the purposes that an additional signal could serve if it was introduced – see Anderson 2 §66. However, given that he accepted that LG 434 disclosed the idea of using an additional signal for the dual purpose of SS block indication and PBCH demodulation and that the skilled person would regard that as a good idea which was worth taking forward, that point has no real significance.[338]Second, in their Opening Skeleton, Samsung raised the question of whether “should consider” meant “should give consideration to” or “should conclude”. This was not the subject of any evidence, but I agree with ZTE that it does not make any difference, for the same reasons.[339]The point of more significance was raised by Mr Anderson in his second report and in his oral evidence. It did not appear from Mr Anderson’s first report that there was any material difference between the experts as to the disclosure of LG 434. For example, he summarised the disclosure relating to proposal 2 as “the document outlines that further to its use (in the multi-beam case) for indicating an SS block index, the additional signal could also be used for PBCH demodulation (in both the single and multi-beam cases)” (Anderson 1 §299).[340]In his second report, however, Mr Anderson appeared to be suggesting that proposal 2 would be read as referring to an “additional SS” (i.e. a synchronisation signal) rather than just an “additional signal” and that there would be some issues involved in using a signal both for channel estimation and hence demodulation and also for transmitting information (see Anderson 2 §§61-66). He maintained this view in his oral evidence. It emerged, however, that that was based on the assumption that LG was intending to adopt the third bullet point in the list of possible mechanisms set out by RAN1, rather than proposing another mechanism, as that list permitted (see Anderson 2 §61 & [T3 290/23–291/25]).[341]This point was not put to Dr Wong, and ZTE submitted that there would be no reason for the skilled person to read into LG’s proposal the requirement that the additional signal be a synchronisation signal, given that they were proposing a new idea of using an additional signal for the purpose of PBCH demodulation as well as SS block indication. However, ZTE also submitted that the point did not appear to matter, because Mr Anderson explained that being an SS would not require the signal to have any additional function (see [T3 293/14–295/11]) nor did he suggest that it would require it to have any particular properties. ZTE suggested the point seemed to have relevance to Mr Anderson when it came to considering the Ad Hoc meeting report’s agreement about signals for PBCH demodulation (see [T3/292/5-6 & 320/9-24]). This is a point I return to below.

LG 438 – disclosure

[342]LG 438 – disclosure Save in one respect, it is unnecessary for me to describe the disclosure of LG 438. It is, however, necessary to discuss the scope of an admission by Samsung that integer C of claim 1 was disclosed by LG 438.[343]This issue emerged only in closing argument. Samsung’s point was that the DMRS in LG 438 is a pure reference signal and does not carry multiple sequences (for the SSB index or at all). Samsung relied on Dr Wong’s acceptance of this point in cross-examination at [T2/190] and said that they have always accepted that LG 438 discloses a DMRS, but has always denied that it carries multiple sequences.[344]By contrast, in their closing at [100], ZTE simply submitted that Samsung had accepted that integer C (which contains the claim features relevant to the IFDM/bandwidth feature) is disclosed by LG 438. ZTE also pointed out that they had included the same text and point in their Opening, at [139], but it had not drawn any comment or denial from Samsung in their oral opening submissions, and, furthermore, there was no hint of the arguments which emerged in closing.[345]To resolve this, it is necessary to start with Samsung’s Reply Statement of Case on Validity, served on 29 September 2025. Paragraph 2 says that ‘Annexes 1 to 5 ….

(d) :

‘The extent to which the Claimants accept (i.e. admit) the Defendants’ case as to which integers of the claims of EP 154 are disclosed by the prior art.’
Annex 3 addresses LG 438 in relation to claim 1 on B1/p167 and sets out the same break down of claim 1 as set out at [314] above. The column headings are ‘Integer’, ‘Exemplary disclosures relied upon by the Defendants’ and ‘Claimants’ Reply’. The relevant extracts in the table are these:[346]For ZTE, Mr Tappin pointed out that if Samsung had really been saying that the DMRS disclosed in LG 438 was a pure reference signal (having only one sequence), then they would not have accepted that integer 1C was disclosed. He also pointed out that ZTE had relied on that admission, meaning that it had not been necessary to cross-examine Mr Anderson on Integer 1C, and that there had been no application to withdraw the admission. He submitted it was not open to Samsung to take the point, albeit his final point was that it does not affect his collocation case.[347]Mr Nicholson pointed out that this table concerned ZTE’s obviousness case over LG 438 alone, a case which ZTE never pursued. He submitted that ZTE were effectively taking the admission out of its proper context i.e. the case of obviousness over LG 438 alone. Furthermore, he submitted that the acceptance that integer 1C was disclosed had to be read together with the fact that integer 1D was not accepted to be disclosed. Mr Nicholson submitted in terms:
‘The point that my clients have always made is that what 438 discloses is, yes, it discloses a DMRS when it comes in on integer 1(c) but at 1(d), the sequence of the DMRS is not accepted.’
And ‘It is [not] realistic or fair for ZTE to try and redeploy the pleading for the purposes of collocation by arguing that we have admitted something which we did not and which is plainly untrue. The consequence is that even if [ZTE] get to this late stage in their journey on collocation, there is no case that it is obvious to develop 438 to have a multi-sequence DMRS and that is the end of the collocation case as a whole.’

And

[348]In his reply, Mr Tappin made valid points that: i) In their pleading, Samsung set out the extent to which they accepted that the claim integers are disclosed by the prior art and that cannot differ depending on the purpose for which the prior art is considered. ii) In response to Mr Nicholson’s point that Samsung did not accept Integer D, that Integer D is about indicating the block index using a sequence of the DMRS, and that cannot detract from the admission on Integer C.[349]Mr Tappin also disputed the import of Dr Wong’s answer. The question and his answer were as follows: 19 Q. One of the things that LG does not consider in this TDoc is 20 using DMRS to send the SSB index. It only looks at the DMRS 21 as a pure reference signal. 22 A. Yes.[350]Mr Tappin argued that using the DMRS only to demodulate does not mean it must be a single sequence [T5/511/15-16]. That is a rather fine point which, in my view, does not detract from the fact that Dr Wong clearly accepted LG 438 only looked at the DMRS as a pure reference signal.[351]What is extraordinary about this whole episode is that, when accepting integer 1C was disclosed in LG 438, Samsung were making the error which they accused ZTE of making: not using a uniform (and correct) construction of DMRS in the claim.[352]This dispute is very unfortunate. In my view, Samsung should have grasped this nettle in their opening and not left it to blow up only in closing argument. Alternatively, they should have been clearer in the pleading in the first place. Whether the dispute actually needs resolving depends on whether ZTE succeed in establishing that claim 1 is a collocation. If I assume ZTE’s collocation argument is correct, nonetheless I confess I would feel uncomfortable invalidating this claim on the basis of this ‘admission’ when it seems clear that LG 438 does only disclose a DMRS as a pure reference signal, and ZTE did not pursue their pleaded case of obviousness over LG 438 on its own.[353]I also bear in mind that Mr Anderson’s written evidence was clear and to the same effect as the pleading. In his first report at [352] he said:
‘…there is no description of using a sequence of a DMRS to indicate an SSB index. Therefore, whilst the features of Integers 1B and 1C are disclosed, LG 438 does not disclose Integer 1D of Claim 1.’
[354]I take Mr Tappin’s point that he was deprived of the opportunity to cross-examine Mr Anderson on this due to the pleading, but, in view of Dr Wong’s clear acceptance, I rather doubt that Mr Tappin would have managed to extract the opposite view from Mr Anderson, not least because of the further teaching in LG 438 that the PBCH may be used to signal a block index (i.e. not the DMRS).

ALLEGED LACK OF INVENTIVE STEP

[355]ALLEGED LACK OF INVENTIVE STEP Applicable Legal Principles These are very familiar, but it does no harm to remind oneself of them. As usual, the parties wished to emphasise different parts of the authorities and different dicta. I gather the topics under the following headings.

Overall approach

[356]Overall approach Both sides referred to the statements of principle in Actavis v ICOS [2019] RPC 9 at [52]-[73]. Samsung stressed the endorsement at [63] of the statement of Kitchin J. (as he then was) in Generics v Lundbeck [2007] EWHC 1040 (Pat); [2007] R.P.C. 32 at [72]. In most cases, it is helpful for the Court to approach this question by adopting the structured approach set out in Pozzoli. But neither approach can replace the statutory question itself. It must be assessed by reference to the facts and circumstances of the case (see [58] - [62]).[357]For their part, ZTE drew attention to the statement at [93] that no formula should distract the Court from the statutory test. The Supreme Court endorsed the following dictum of Jacob LJ in Generics v Daiichi [2009] R.P.C. 23 at [17]:
“There is at bottom only one test, namely that posed by Art.56 of the EPC transposed into UK law by s.3 of the Patents Act 1977. Was the invention obvious to a person skilled in the art having regard to any matter which forms part of the state of the art? Judicial or patent office attempts to formulate the test in other words, or to provide a formula, can be helpful, provided that one does not lose sight of the statutory question. One must not take any such other test or formula as if it were the statute – they are only tools for answering the statutory question. Adherence to any rigid formula can be a mistake.”
[358]Amongst the factors identified by the Supreme Court which can, depending on the facts and circumstances of each case, be relevant to the assessment of obviousness, ZTE also drew attention to the endorsement by the Court of the statement of Laddie J in Brugger v Medic-Aid [1996] R.P.C. 635 at 661:
“[I]f a particular route is an obvious one to take or try, it is not rendered any less obvious from a technical point of view merely because there are a number, and perhaps a large number, of other obvious routes as well.”
[359]ZTE also reminded me of the succinct statement of Kitchin LJ in Medimmune v Novartis [2013] R.P.C. 27 at [93]:
“Ultimately the court has to evaluate all the relevant circumstances in order to answer a single and relatively simple question of fact: was it obvious to the skilled but unimaginative addressee to make a product or carry out a process falling within the claim.”

Approach to the prior art

[360]Samsung submitted that how the skilled person approaches the prior art is important, relying on this passage from the judgment of Birss J. (as he then was) in Accord v Medac [2016] RPC 17, [2016] EWHC 24 (Pat) at [64]:
‘Medac referred to the point addressed by Floyd J (as he then was) in Dr Reddy's Laboratories v Eli Lilly [2008] EWHC 2345 (Pat) at paragraph 170. There the judge observed that there can be a risk in focussing too much on the disclosure of any particular document and losing sight of the whole common general knowledge. Medac submitted that while the law requires that the pleaded prior art be notionally read with interest by the skilled person, that person does not approach it on the assumption that that particular document (out of all the others directed to the same problem) in fact contains pointers towards the solution, and an unnatural focus on it may lead to an unbalanced analysis and hindsight. I agree with that submission. The key issue is that the skilled person does not approach a document on the assumption described. To do so would indeed involve hindsight.’

Mosaicking

[361]Samsung made the well-known point that, in general, it is not permissible to rely upon a “mosaic” of prior art documents. Instead, a novelty or obviousness attack must start from a single disclosure and reference may only be made to other documents in particular circumstances.[362]For the purposes of novelty, the circumstances are those identified in Advanced Cell Diagnostics v Molecular Instruments [2024] EWHC 898 (Pat) at [335]:
‘As to mosaicking, it is wrong to say that there is an absolute rule against combining documents for the purposes of anticipation. See Terrell on the Law of Patents, 19th Ed., 11-61 to 11-63. But it only becomes possible if one document points to another, and MI did not argue other than that the pointer has to be to the overall standard of clear and unmistakable directions, which I believe must be correct. Similarly, the fact that there is a general cross-reference from document A to document B does not of itself entitle a party attacking a patent to pick and choose anything from the disclosure of document B to add to document A, any more than it would be permitted to combine parts of document A if there were no disclosure, to the necessary standard, to do so (see Terrell at 11-63). One has to ask to what, in document B, there is a clear and unmistakable pointer.’
[363]For obviousness, “unlike novelty, it is permissible to make a ‘mosaic’ out of the relevant documents, but it must be a mosaic which can be put together by an unimaginative man with no inventive capacity.” (See Judgment of Lord Reid in Mills & Rockley v Technograph [1971] FSR 188 at 193). As Samsung submitted, although there is thus a lower hurdle for another document to be brought into the obviousness analysis, it remains necessary to be clear as to why the skilled person is going to that document and for what they are looking. (One still has to ask, to what material it is obvious to go in the second document?).[364]ZTE reminded me that an obvious mosaic can arise where there is a cross-reference in one prior art document to the other, however, this is not the only way. This point was made by Laddie J in Pfizer’s Patent [2001] F.S.R. 16 as follows:
“When any piece of prior art is considered for the purposes of an obviousness attack, the question asked is "what would the skilled addressee think and do on the basis of this disclosure?" He will consider the disclosure in the light of the common general knowledge and it may be that in some cases he will also think it obvious to supplement the disclosure by consulting other readily accessible publicly available information. This will be particularly likely where the pleaded prior art encourages him to do so because it expressly cross-refers to other material. However, I do not think it is limited to cases where there is an express cross-reference. For example if a piece of prior art directs the skilled worker to use a member of a class of ingredients for a particular purpose and it would be obvious to him where and how to find details of members of that class, then he will do so and that act of pulling in other information is itself an obvious consequence of the disclosure in the prior art.”
[365]I also bear in mind that matters which are not the subject of an explicit cross-reference, and which fall short of common general knowledge, are capable of being taken into account for obviousness purposes if the information would be acquired by the skilled person as a matter of routine. This was explained by Arnold J. in KCI v Smith & Nephew [2010] EWHC 1487 (Pat) at [108]-[112].

Avoiding hindsight

[366]Avoiding hindsight It is axiomatic that hindsight has no place in an assertion of a lack of inventive step, so a key consideration is whether or not hindsight has crept into the analysis. As Lord Hodge in Actavis v. ICOS [2019] UKSC 15 at ¶72; JA2/21/p.849 recited: Eighthly, the courts have repeatedly emphasised that one must not use hindsight, which includes knowledge of the intention, in addressing the statutory question of obviousness. …[367]Samsung submitted in closing that “knowledge of the invention” was a real problem in this case. They pointed out that Dr Wong readily accepted in cross-examination that, as a consequence of this prior knowledge of 5G as an expert in initial access, before he was even contacted by ZTE’s Solicitors, he already knew about how the Patent’s solution had been implemented in 5G. In cross-examination he was taken through each and every integer of Claim 1 and he acknowledged that each was known to him at the outset, see [T2/77/7-78/22].[368]Samsung also argued that no attempt was made in any of Dr Wong’s expert evidence to acknowledge that he knew about every aspect of the invention at the outset; still less to(a) identify how he knew about the invention and when; or(b) reflect carefully on how that might influence him. Dr Wong acknowledged this in cross-examination at [T2/79/15-80/3].[369]Samsung’s point was that this was no criticism of Dr Wong, but was contrary to the guidance given by Meade J in Fisher & Paykel v. Flexicare [2020] EWHC 3282 (Pat) at [21] (emphasis added): ‘Where the expert already knows the invention there may yet be value in sequencing the documents that he or she reviews to focus the mind on avoiding hindsight, but the opportunity to give a completely untainted view of the prior art does not exist; the expert has to discipline themself carefully to avoid hindsight. If they do so well then there is no reason why they cannot give cogent evidence on obviousness, but in such a situation I think it must be important for the expert to identify how they knew about the invention and when, and to reflect carefully on how that might influence them. This is really where the problem with Dr Dixon arose and it is an issue of the assessment of his evidence, not a disagreement between the parties on the applicable principles.[370]The issue of hindsight and prior knowledge featured heavily in Samsung’s cross-examination of Dr Wong. Samsung argued that at no stage did he make any attempt to explain or qualify his position when it was suggested to him that he was making the right choice in part because of his personal knowledge, relying on examples at [T2/125/4-15]; [T2/128/11-13]; and [T2/138/7-139/6]. They submitted that the absence of any attempt by Dr Wong to explain how his evidence was independent of his past knowledge in oral cross-examination (mirroring the approach in his written evidence) very much suggested that those instructing him had not ensured that he was sufficiently aware of the importance of the point.[371]Ultimately, Samsung suggested that great care needed to be taken with Dr Wong’s evidence as to what would or would not have been apparent to his Skilled Person. I keep this point very much in mind.

Technograph and step-by-step

[372]Technograph and step-by-step Samsung made the point that a common and well-known indicium of hindsight inadvertently slipping into an obviousness analysis is the Technograph step-by-step journey from the prior art to the claims of the patent characterised by the skilled person facing a choice at each juncture yet, with but thin reasoning, always managing to select the path which leads ever-closer to the claimed invention. Samsung relied on the following well-known dicta. First, as Lord Hodge in Actavis v. ICOS explained (referring back to Lord Diplock in Technograph) (¶72):
‘The obvious danger of a step by step analysis is that the combination of steps by which the inventor arrived at his invention is ascertained by hindsight knowledge of a successful invention.’
[373]Second, Lord Hodge (at [72]) further quoted, with approval, the statement of the same fundamental principle set out by Birss J. (as he then was) in Hospira v. Genentech [2014] EWHC 3857 (Pat) at [240]:
‘The particular point made in Technograph was that it was wrong to find an invention was obvious if it was only arrived at after a series of steps which involve the cumulative application of hindsight. In some circumstances success at each step in a chain is a necessary predicate for the next one and it is only the hindsight knowledge of the invention as the target which could motivate a skilled person to take each step without knowledge about the next one. In a situation like that, Technograph is important.’
[374]Third, in guiding the proper approach to the evaluation of a step-by-step journey from the prior art to the claim, Lord Hodge in Actavis v. ICOS, ¶72 also referred with approval to the approach set out by Floyd J. (as he then was) in Gedeon Richter v. Bayer [2011] EWHC 583 (Pat) at [114]:
‘I think that the guiding principle must be that one has to look at each putative step which the skilled person is required to take and decide whether it was obvious. Even then one has to step back and ask an overall question as to whether the step by step analysis, performed after the event, may not in fact prove to be unrealistic or driven by hindsight.’
[375]All these well-known dicta provide an incentive for the patentee to identify as many steps as possible but it needs to be remembered that more steps are not necessarily better. Furthermore, reliance on steps which are not really distinct stages in the analysis tends to cast doubt on the remaining steps.

Paper tigers / ‘ideas patents’

[376]Paper tigers / ‘ideas patents’ ZTE also submitted that, depending on the way Samsung argued their case, it might be necessary to consider the cases on when patentability can be justified by showing that a technical prejudice is mistaken, relying on the following dicta.[377]First, the following passage in Pozzoli v BDMO [2007] F.S.R. 37 at [27]-[28], where Jacob LJ said:
“27. Patentability is justified because the prior idea which was thought not to work must, as a piece of prior art, be taken as it would be understood by the person skilled in the art. He will read it with the prejudice of such a person. So that which forms part of the state of the art really consists of two things in combination, the idea and the prejudice that it would not work or be impractical. A patentee who contributes something new by showing that, contrary to the mistaken prejudice, the idea will work or is practical has shown something new. He has shown that an apparent ‘lion in the path’ is merely a paper tiger. Then his contribution is novel and non-obvious and he deserves his patent. 28. Where, however, the patentee merely patents an old idea thought not to work or to be practical and does not explain how or why, contrary to the prejudice, that it does work or is practical, things are different. Then his patent contributes nothing to human knowledge. The lion remains at least apparent (it may even be real) and the patent cannot be justified.”
[378]Second, in Philips v Asustek [2020] R.P.C. 1 at [73], Floyd LJ referred to the foregoing passage of Pozzoli and said:
“[...] The principle is that you cannot have a patent for doing something which the skilled person would regard as old or obvious but difficult or impossible to do, if it remains equally difficult or impossible to do when you have read the patent. To put it another way, the perceived problem must be solved by the patent.”
[379]To similar effect, third, ZTE also relied on the explanation by Birss LJ in Interdigital v Lenovo [2023] EWCA Civ 34 at [33]-[37]. I accept the principle, but it is also important to recognise that the prejudice in question must be of the relevant kind – as Birss LJ pointed out at [40].[380]Fourth, that similar considerations apply where a patent is an “ideas patent” -see Nokia v Oneplus [2022] EWHC 2814 (Pat) at [172]-[173]:
‘172. Oppo relied on the decision of Henry Carr J in Garmin v Koninklijke Philips [2019] EWHC 107 (Ch) and said that the Patent was an “ideas patent”. 173. I dealt with a similar submission in Shenzhen Carku v Noco [2022] EWHC 2034 (Pat). I maintain the view I expressed there; ideas patents are not a separate statutory category and it is necessary for a party attacking a patent to show that it is obvious to perform the invention. But this does not mean I disagree with Henry Carr J, because his judgment made the valuable points that a patentee cannot rely for inventive step on problems of implementation which the patent does not solve, and inventive step has to be assessed at the level of generality of the claims. Those were the propositions relied on by Oppo and I accept them.’
[381]I have read and considered these passages and intend to apply them.[382]The final point I have in mind concerns the evidence from the experts. It is not so much the opinions they give which matter, it is the reasons they give for holding those opinions which are key. On this see Jacob LJ in Technip France SA’s Patent [2004] EWCA Civ 381, [2004] RPC 46 at [15], SmithKline Beecham Plc v Apotex Europe [2004] EWCA Civ 1568, [2005] FSR 23 at [52]-[53] and Schlumberger v. EMGS [2010] EWCA Civ 819 at [86].

Application to the Facts

[383]Application to the Facts Overview I proceed on the basis of Dr Wong’s Skilled Person and Dr Wong’s CGK, as set out above.[384]As is often the case when the patentee responds to an allegation of obviousness, Samsung sought to identify a whole series of individual steps which Dr Wong’s skilled person had to take as part of ZTE’s obviousness case. Samsung also divided the analysis into three phases of what they termed the overall ‘journey’ to get from LG 434 to claim 1. It is necessary to set out these three phases.[385]Before doing so, I make the point that this section includes many transcript references, a testament to the level of detail argued by both sides on the underlying points.

Phase 1 – Pursuing LG 434’s Proposal 2

[386]Phase 1 – Pursuing LG 434’s Proposal 2 Samsung’s contentions Samsung’s starting point was to contrast what they said was Dr Wong’s assumption in his written evidence that the Skilled Person would pick up LG 434 and pursue Proposal 2, with their list of pre-conditions which had to be met before Proposal 2 was even relevant. I set out Samsung’s pre-conditions here: i) First, Choose the Index Method: the Skilled Person has to decide to use LG 434’s Alt 2 (multiple index method) as Proposal 2 is only presented in the context of Alt 2 [T2/105/16-22]. Both experts said that it was possible to apply Proposal 2 to Alt 1 (the single index method), but that realisation is itself a step which the Skilled Person has to take (see Anderson XX [T3/275/11-276/5]). ii) Second, Determine the PBCH is too small: following LG 434, the Skilled Person has to determine that the PBCH will not have sufficient space for both the block index and the burst index (or a combined index) to be carried as PBCH payload [T2/105/23-106/2]. iii) Third, Decide not to use the SSS: The Skilled Person has to decide not to extend the SSS sequence to carry the block index [T2/106/3-14]. iv) Fourth, Decide to add an additional signal: The Skilled Person has to decide to add an additional signal to carry the block indication, rather than, for example, using one of the other mechanisms that was left in the list of possible options (by RAN1, Agreement as to possible mechanisms to indicate the SS block index) [T2/106/15-19].[387]Only after those four decisions have been made does Proposal 2 become relevant, according to Samsung. At that point, Samsung submitted that Dr Wong accepted that further decision steps were nevertheless still required, namely: i) Fifth, Decide to pursue Dual Purpose approach: The Skilled Person has to then decide (having been told to contemplate dual purpose) that it is a good idea to use the additional signal for a dual purpose [T2/106/25-107/4]. ii) Sixth, Decide on that other Purpose: LG 434 gives “PBCH demodulation” merely as an example use for the additional signal alongside “SS block indication” [T2/105/13-15]. The Skilled Person therefore has to decide that they will follow this example rather than some other use [T2/107/5-17], for example rather than, say, adding a TSS and using it for the dual purpose of block indication and reducing the burden on the SSS [T2/125/4-126/20].[388]Samsung argued that Dr Wong readily accepted that LG 434 does not assist his Skilled Person with any of these decisions [T2/107/18-108/4], and no-one has suggested (quite rightly) that any of them had already been taken by RAN1, for if they had LG would not need to be proceeding on a conditional basis.[389]Samsung emphasised that the difference between the obvious approach promulgated by Dr Wong’s written evidence in which he picked up Proposal 2 as being effectively instructions for the Skilled Person to ‘add a signal for the dual purposes of carrying at least part of the SSB index and demodulating the PBCH’, and what he accepted was actually proposed in cross-examination could not be starker.[390]So Samsung said that at least 6 separate technical decisions are required for Dr Wong’s Skilled Person to even begin to head off in the direction which Dr Wong, with knowledge of 5G, took in a single step without need for any decision at all.[391]Samsung also stressed that these are not simple routine decisions and submitted that, without his eye on the prize, in the context of Proposal 1 (which is itself irrelevant for the obviousness case), Dr Wong immediately told the Court that his Skilled Person would turn to simulations in order to determine whether Proposal 1 (which actually proposes the ‘localised type’) should be accepted or not [T2/108/16-23].[392]When asked about the decisions as to whether Proposal 2 was even going to be a relevant proposal, Dr Wong (having made no mention of simulations) was somewhat more reluctant as to how one might go about choosing between indices, but made clear that deciding, for example, what space was available on the PBCH was not straightforward [T2/110/5-112/25]. As Mr Anderson explained, further technical information or analysis would be required by the skilled person as LG 434 is limited to verbal reasoning which he opined was not particularly robust [T3/288/21-289/7].

ZTE’s contentions

[393]ZTE’s contentions ZTE argued that Samsung’s approach was highly artificial and seemingly dependent on LG 434 being read in a linear way, with each decision being made before proceeding further. ZTE argued that the Skilled Person would read the whole document and consider Proposal 2, and in so doing, they would have in mind the undesirability of putting bits on the PBCH and adding hypotheses to the SSS.[394]I should explain those two points a little further. As to the first, Dr Wong explained that during initial access the goal is to convey the synchronisation information very quickly, and adding bits to the PBCH increases the amount of computation needed by the UE at that stage – Wong 1 §199. To similar effect, Mr Anderson explained that the goal is always to try to reduce the number of bits needed on the PBCH and agreed that therefore the skilled person would recognise the benefit in an approach which minimised the number of bits of information that had to be encoded on the PBCH [T3/274/7–275/3].[395]As to the second point, ZTE argued as follows: i) LG 434 identifies an issue with using the SSS, namely the need for additional hypotheses for indicating the SS block index. ii) The SSS was already required to carry part or all of the cell ID and the working assumption was that there would be about 1000 cell IDs (an increase from the 504 in LTE, which was also the number in the TR) – see Wong 1 §170. iii) So the skilled person would know that the SSS was likely to need a considerable number of hypotheses to convey cell ID information – Anderson [T3 277/11–278/14]. iv) As Mr Anderson explained, in order for the SSS to accommodate further hypotheses without reducing reliability of detection, it would be necessary to lengthen its sequence, which would require allocating more resources to the SSS and increase detection complexity in the UE [T3 278/15–279/10]. v) Dr Wong’s view was that the skilled person would therefore regard using the SSS to indicate the SS block index as not a preferable solution – see Wong 3 §20.[396]On this point, ZTE also relied on a Samsung Tdoc submitted for the same meeting [DXX-NA/2], a document which was put to Mr Anderson in cross-examination, in which Samsung identified three possible ways of indicating the SS block index: PSS or SSS, PBCH and new type SSS i.e. TSS. There Samsung said [DXX-13] that:
“If this SS block index indication functionality is given to NR-PSS/SSS without allocating additional resources, the symbol boundary detection or cell ID acquisition performance would be degraded due to the increased hypotheses for NR-PSS/SSS detection.”
Samsung went on to explain why implicit signalling of the SS block index on the PBCH was not a good idea either, because it would lead to decoding complexity for the UE. Therefore, it proposed using a new SS, i.e. a TSS, to indicate the block index. ZTE’s point was that Samsung had not had the idea, which LG had had, of using an additional signal for PBCH demodulation as well: Anderson [T3/280/9–282/2].[397]On Samsung’s third step, Mr Anderson’s view was that the skilled person would not rule out using the SSS but instead would want to consider it as one of the possible approaches, to decide which was the most efficient way of signalling the SS block index – [T3 279/11–280/8 & 282/3-13].[398]It was put to Dr Wong that the skilled person might think of using the additional signal for SS block indication and a purpose other than PBCH demodulation [T2 107/5-17, 114/9-21 & 118/4-20]. Mr Anderson had not suggested that in his reports and he confirmed that the thrust of LG 434 was the dual purpose of SS block indication and PBCH demodulation [T3 303/19–304/11].[399]As to Proposal 2 itself, Dr Wong said that the skilled person would agree with that proposal (Wong 1 §207). He did not agree with the suggestion that the skilled person would reject the idea on the basis that it required moving away from a pure reference signal for demodulation (a point not made by Mr Anderson) – see [T2/135/21–137/22 & 140/24–141/23] (where Dr Wong explained that it would not be necessary to use coherent detection).[400]Mr Anderson accepted that LG 434 was giving the skilled person the idea of using an additional signal in the SS block to both indicate the SS block index and to assist with demodulation of the PBCH – [T3/285/23–286/3] (see also [T3 289/23–290/22] where he sought to suggest that did not add much to the CGK).[401]Finally, ZTE submitted that Mr Anderson also accepted that the skilled person would regard that idea as a good one which was worth taking forward [T3/286/20–287/8]: ‘Q. Would you agree the skilled person would see this idea of using a signal for a dual purpose as a good one? A. I think, yes, in general. Q. Especially when they know they are going to need to have a signal to indicate the SS-block index and they are going to need to have a signal to demodulate the PBCH. A. Yes. Q. Therefore, it would be a good idea to use a single signal for those dual purposes. A. Yes. Q. There is nothing that would make the skilled person think this was not an idea worth taking forward, is there? A. I do not think so. … ‘ A. I do not think so. … ‘

Analysis

[402]On these ‘decisions’, Samsung rely on a relatively short passage of Dr Wong’s cross-examination which I have reviewed with care. It is true he accepted these decisions needed to be made but it is clear he did not regard them as difficult or anything other than straightforward. It is also clear from his answers that he took a more positive message from LG 434 – for example, he said he thought that LG would prefer an additional signal, probably, and that the suggestion to use the signal for PBCH demodulation and SS block indication was probably what they had in mind. For that reason, Samsung’s argument in [388] above was not supported by the cross-examination referred to, although Dr Wong did accept that there was nothing in LG 434 to help the skilled person to say whether they would have enough space on their PBCH or not, but that point ignores CGK.[403]Overall, I consider that Samsung made a mountain out of a molehill in making these points. Accordingly, in my view, the starting point for the obviousness analysis based on LG 434 is that the Skilled Person would regard Proposal 2 as a good idea worth taking forward.

Phase 2 of the LG 434 Journey – Choosing ‘self-contained DMRS’

[404]Phase 2 of the LG 434 Journey – Choosing ‘self-contained DMRS’ Samsung’s arguments then proceeded to their Phase 2. Samsung submitted that Dr Wong’s ‘quest’ moved on to phase 2, which was investigating what RAN1 had decided about signals for demodulating the PBCH (i.e., already under the assumption that his Skilled Person was going to use one of those signals to indicate the SS Block Index). In this Phase 2, it is convenient to consider the arguments from both sides as they come to bear. Again, ZTE’s initial argument was simple, as contained in Dr Wong’s evidence. ZTE’s argument in closing I consider below at [428].[405]For this investigation, Dr Wong turned to the Ad Hoc Minutes (a part of which he had quoted in Wong 1/¶208): For reference signal of NR-PBCH demodulation, down selection will be done in RAN1#88 to one of the following:• Alt.1: Synchronization Signal (e.g. NR-SSS)• Alt.2: Self-contained DMRS ◦ NOTE: It does not preclude additional channel estimation aid from synchronization signal.• Alt.3: MRS multiplexed in an SS block, if MRS is supported in an SS block.[406]Samsung’s first issue with this minute was that it is not the same as a conventional list of CGK, e.g., techniques for joining two pieces of wood:(1) nailing;(2) screwing;(3) gluing – from which the skilled person is free to choose, as they see fit, between the individually CGK options, all of which represent a solid basis for further work. Rather, they said that this list of 3 alternatives sets out possible contenders within RAN1, only one of which is likely ultimately to be chosen – and will need to “be the subject of much discussion, simulations and so on before the skilled person would know which is the right approach”. This was part of their ‘RAN1 bound’ argument. In this regard, Samsung pointed out that Dr Wong readily accepted that – “they have no idea which one will be used” [T2/121/16-122/4]. Samsung’s point was that, insofar as the Skilled Person is going to ‘choose’ one, that choice is therefore an important part of their obviousness journey, and has to be justified as an important step in the process.[407]Samsung submitted that, in his written evidence, knowing that 5G went for the DMRS option, Dr Wong’s Skilled Person rejected Alt 1 and Alt 3, leaving themselves with the “self-contained DMRS”. Samsung explored his reasons for this in cross-examination.[408]In relation to Alt 1, Samsung contended that Dr Wong made two key errors: i) First, his reason for rejecting the express example in Alt 1 (i.e. use of the SSS) had nothing to do with selecting the SSS as the means for demodulating the PBCH [T2/123/4-124/18]. Samsung argued that LG 434 had rejected the SSS as being suitable for being extended to carry the SSB Index but submitted that does not mean that RAN 1 would necessarily reject it as the signal for demodulating the PBCH; ii) Second, Dr Wong had again overlooked the fact that the document was recording only an example; RAN1 had agreed a “Synchronisation Signal”, with “NR-SSS” as a mere example. When asked about this, he accepted:(1) that a Tertiary Synchronisation Signal (TSS) was within the scope of Alt 1 [T2/117/6-118/3];(2) that RAN1 had a minuted agreement, referred to in Wong 1 [154] as CGK, to decide whether there should be a TSS [T2/116/7-24]; and(3) that the TSS would meet all the requirements of both LG 434’s Proposal 2 (as being an additional signal suitable for carrying the SSB Index) and the minuted demodulation requirements of RAN1 [T2/125/16-126/20].[409]With these matters in mind, Samsung argued that Dr Wong’s Skilled Person’s rejection of Alt 1 was not justified and would not have reflected the hindsight-free actions of his Skilled Person.[410]In relation to Alt 3 (use of an ‘MRS’), Dr Wong accepted that the reasons he gave in his written report (Wong 1 ¶215) had nothing to do with any new learning from LG 434, and amounted to his Skilled Person simply disagreeing with RAN1 that Alt 3 “deserved a place on the list”, i.e. RAN1’s list of potential signals for demodulating the PBCH [T2/127/9-128/10]. Given Dr Wong’s Skilled Person’s deference to the ‘agreements’ of RAN1, Samsung suggested this was a surprising contention.[411]As Samsung pointed out, MRS never made it into 5G [T2/128/11-13], and Samsung suggested that may have coloured Dr Wong’s thinking. Whatever the position was at the Priority Date, at the very least, Samsung argued that resolving that (contrary to the RAN1 minutes Dr Wong quotes) MRS was no longer a contender was a complex question which required detailed consideration of other topics. Samsung said it was not a simple case of crossing it off the list as if it were never mentioned.[412]So Samsung’s point was that, again, the simple dismissal of Alt 3 by Dr Wong’s Skilled Person was entirely unjustified.[413]In his written evidence, Mr Anderson made a rather subtle point. Having summarised his understanding of the approach of Dr Wong’s Skilled Person in Anderson 2 [73], he pointed out this differed from the approach of the Skilled Person in his first report which he summarised as:
‘…they do not consider LG 434 to provide sufficient justification or analysis on which to base a preference (for the means to indicate a block index), and to the extent that they consider the additional signal, they understand that its design would be influenced by its need to convey information and by the structure and roles of other signals that may be present within an SSB.’
[414]This followed his evidence in relation to the MRS, where in [71] he agreed that Alt 3 would be less relevant if the MRS (which he understood to mean more generally the signals used for L3 mobility) in idle mode would be the SS and/or the DMRS for the PBCH (as opposed to specifically designed MRS). In cross-examination, Mr Anderson agreed that premise [T3/325/14-20], and on that premise, that Alt 3 was not a separate option. In their closing submissions, Samsung attempted to put a different gloss on these answers, submitting that the cross-examination did not reach any such conclusion. I disagree. Counsel secured clear answers [T3/325/8-326/6].[415]When it came to the remaining option, Alt 2, Samsung submitted the “Self-contained DMRS” was described by Dr Wong (who of course knew what 5G ultimately did) without hesitation as the only “good option” for demodulating the PBCH. When asked in cross-examination, he confirmed that his Skilled Person, coming from LG 434, was choosing the DMRS (in his Wong 1 [213] and [216]) without ever having given any consideration to its suitability as a dual-purpose signal [T2/128/13-130/2], instead by a process of elimination. Samsung argued that this is how one goes stepwise through a journey towards a known destination, but that it is not how a Skilled Person would really behave. The Skilled Person is looking for a signal which is suitable for two purposes – as such, a signal would not get selected without considering whether it is suitable for both purposes. For this reason, Samsung submitted that Dr Wong’s Skilled Person’s immediate embrace of DMRS for signalling (i.e. the second purpose) is a pure hindsight step.[416]I understand Samsung to make a subtle point here: it is not that they were saying a ‘self-contained DMRS’ was not suitable. Rather, they were pointing to the absence of consideration by Dr Wong of the options open to the Skilled Person and a choice based on consideration of those options.[417]Samsung drew attention to how Dr Wong had described, in his first report at Wong 1 [217], how the Skilled Person would go about deciding on the indication method. The significance of [217] is that it was the final paragraph of Dr Wong’s analysis of the disclosure of LG 434:
‘217. With regard to the indication method, the Skilled Person would be aware of a range of implicit signalling methods that could be used to transmit the SSB index on the signal according to proposal 2, such as those used during the cell search / initial access procedure in LTE. As I have said above, one approach would be to use the sequence of the reference signal (in the same way that the cell ID was indicated via the PSS and SSS in LTE). An alternative would be to implicitly indicate the SS block index based on one of the other CGK methods, such as varying the location of the additional signal’s resource elements, i.e. starting it at an offset of 0, 1, 2, 3… REs within a symbol. However, in practice, this would provide less flexibility as there would be a more limited number of locations compared to the number of different sequences that could be used.’
[418]This paragraph must be read with his later [448]:
‘448. As I have explained above when considering the obvious steps in view of LG 434, the Skilled Person would think that the use of a sequence is the most obvious way of implementing proposal 2, and that there would be limited other methods that could be used.’
[419]It must also be read in the light of what he said in his earlier [158], where, in the context of his description of what the Skilled Person would have learnt from the RAN1 Ad-Hoc Meeting in January 2017, Dr Wong said this:
‘158. Possible mechanisms for indicating the SS block index were included with the same set of agreements. There were two approaches to using the PBCH, namely ‘implicit indication’ and ‘explicit indication’
. The explicit mechanism would involve directly encoding the index/indices as channel data. The Skilled Person would consider the implicit mechanism to cover a broad range of implicit signalling mechanisms, e.g. using a CRC mask as I have discussed at paragraph 119 above, or the ordering, locations, and hypotheses of any reference signals.’[420]Perhaps not surprisingly, [217] was a particular point of attack for Samsung and they made two points: i) For the first, Samsung started by pointing out that Dr Wong’s Skilled Person has obliged his or herself to carry the SSB index on the DMRS. Samsung’s point was that Dr Wong/his Skilled Person takes this step without giving any consideration as to (as Samsung put it) the downsides of changing a DMRS reference signal (contemplated by RAN1) into a signal which now requires detection before it can provide a channel estimate, relying on [T2/133/21-134/2]. ii) Samsung’s second point was that Dr Wong’s Skilled Person moves immediately to the solution of using sequences on the DMRS for the SSB Index, with only an afterthought mention of using ‘location’ instead.[421]On the first point, Samsung submitted as follows: i) That the absence of proper consideration of the technical merits of changing the nature of the DMRS proposed by RAN1 reeks of hindsight. ii) Even if the Skilled Person thought the difference was surmountable, it is something which should have been carefully set out as part of the decision process. iii) Not pausing to think about it can only properly be explained by ‘knowing the answer’ so as not to need to go through the thought process.[422]Similarly, on the second point, Samsung pointed out to Dr Wong in cross-examination that he had provided (in his [158]) a much fuller list of alternatives when discussing CGK. Dr Wong accepted that other choices were available but gave no real explanation as to why his Skilled Person had not worked their way through the various options in his [217], relying on [T2/132/14-133/17]. This led Samsung to submit that the immediate selection of the system used in 5G, without working through the options, still less rejecting them as unsuitable (which he never suggested) can only be explained by the improper intrusion of hindsight: if one knows the answer, it is only too easy to simply see it as the preferred solution without justification, and with only minimal reference to the existence of just one possible alternative.[423]Samsung were critical of Dr Wong suggesting, in his answers on this point, that the decision might depend on the number of SSB index values (which Samsung accepted seemed credible), but their criticism centred on his hypothesising as to numbers for which no basis had even been identified [T2/131/13-132/13], commenting that, whether they are hypothetical (in which case they should have formed part of Dr Wong’s analysis at the Priority Date), or whether they come from knowledge of what 5G ultimately did (in which case they are impermissible hindsight), we will never know. I leave this criticism out of account. It is not unusual for Counsel’s questions to lead an expert into a level of detail not previously discussed in the expert reports, but they can hardly be criticised for answering the question as they think fit.[424]Notwithstanding the focus on Dr Wong’s [217] in cross-examination, one curiosity is that Mr Anderson did not comment on it directly in his second report at all. For his part, Dr Wong’s second report was very short (in comparison to his first, albeit large parts were no longer relevant by the time it came to reply reports). Evidently, Dr Wong considered what Mr Anderson said in his second report, particularly on matters of CGK, and served his third report on 19 February 2026, in which he indicated he agreed with large parts of what Mr Anderson had said in his second report on CGK, even though the two experts had expressed themselves in different terms.[425]This was perhaps the reason for the lack of direct comment by Mr Anderson on Dr Wong’s [217]. What Mr Anderson had done, however, was to comment on the differences between channel estimation and sequence detection in his [65], as follows:
‘- Channel estimation in OFDM serves to derive a series of estimates H^n that represent the complex channel values across the different sub-carriers ‘n’63. It therefore produces an output for each of the unknown H(n) across the different sub-carrier frequencies, based on the individual elements of the known reference signal. - Sequence detection is a related, but different technical problem that attempts to identify, as a single output, which sequence (from a set of possible sequences) was the most likely to have been transmitted, given the received signal observation and any channel information that is known. To provide the required detection performance in the presence of noise, this would typically be based on a decision metric that is formed or accumulated across the full signal [fn For example, in the present case, across all of its sub-carriers]. As mentioned at paragraph 117 of Anderson 1, coherent detection techniques utilise (and require) knowledge of the propagation channel [fn Which must be obtained in some way, for example from another signal or channel], whereas non-coherent approaches must instead be used when this is not available. The bandwidth of the signal (in relation to the coherence bandwidth of the channel) is also of relevance to sequence detection as this affects both its performance (due to diversity) and the detection methods that may be used. Section 7.3 of “LTE - The UMTS Long Term Evolution From Theory To Practice” (Second Edition) provides a discussion on ‘Coherent Versus Non-Coherent Detection’ in the context of the PSS and SSS in LTE.’
[426]In his third report at [6], Dr Wong agreed with this summary and was at pains to say that he was aware of the distinction when he wrote his first report. He added one point and then continued in his [7]:
‘ …In hindsight, it may have been more accurate for me to say that where a sequence is required to be detected, all of the possible sequences must be known to the UE in advance, even if the actual sequence is not known and has to be acquired using hypotheses. An example might be that the system specifies the type of sequence (e.g., m-sequence) and its length, but the UE must detect the sequence by correlating against candidate sequences which are known to the UE. 7. Where channel estimation is performed, the actual sequence must be known by the UE in advance, rather than merely the possible sequences. Therefore, if the system is specified such that the sequence can take different roots or seeds (for example, to indicate information), then I would agree with Mr Anderson that the sequence would need to be detected first. However, this would simply amount to an additional preceding computational step by the UE. It also does not affect my views at paragraph 203 of my First Report that the Skilled Person would be aware of suitable signals which could be used for both channel estimation and indicating information (e.g., Zadoff-Chu sequences, m-sequences, Gold sequences etc.), and a sequence with good autocorrelation/cross-correlation properties would be desirable for both of these functions.’
[427]Dr Wong was cross-examined on that underlined phrase and he accepted there was a reliability issue associated with changing from using a pure reference signal to detecting a sequence and then using it for channel estimation - see [T2/139/7-140/23], so it was not accurate to characterise it as merely an additional computational step in the UE.[428]In contrast to the thrust of Samsung’s submissions, in their closing ZTE submitted it was obvious for the Skilled Person taking the proposal 2 idea forward to use hypotheses of a sequence to indicate the SS block index, contending that: i) It was a CGK approach for indicating information. ii) Sequences could be used which also had properties needed for providing a channel estimate for demodulation. iii) Dr Wong’s evidence that it was the most obvious approach (see his [448], quoted above). iv) Significantly, Mr Anderson agreed that the use of a sequence to indicate the block index was a likely way of implementation [T3/314/10-315/13], an acceptance that put a significant dent in Samsung’s argument on this point.[429]Dr Wong’s [217] reached a proposal for a DMRS to demodulate the PBCH, which DMRS is also used to carry the SSB Index using sequences. As Samsung pointed out, that did not however reach the claim and so Dr Wong was therefore instructed to proceed to a third phase, a Pozzoli analysis.

Phase 3 of the LG 434 Journey – ‘The Pozzoli Pedestal’

[430]Phase 3 of the LG 434 Journey – ‘The Pozzoli Pedestal’ Samsung’s case was that, for the reasons stated above, the obviousness journey in this case had already been tainted by subconscious hindsight, but that the likelihood of overt hindsight was even more acute as Dr Wong’s approach moves into the Pozzoli phase.[431]In this regard, Samsung submitted that whilst Pozzoli is a useful (though not mandatory) framework which is especially useful for the Court in appropriate cases, real care must be taken with it in the hands of an expert. The problem is that by starting with the claimed invention, and identifying the differences between the prior art, one necessarily puts the inventive step on a hindsight-motivated pedestal. Not only is the fact that the prior art has ‘fallen short’ identified, the way in which it has fallen short, the ‘gap’ or ‘missing piece’ is itself put squarely before the expert’s eyes.[432]At the start of Samsung’s cross-examination of Dr Wong on this phase, Counsel confirmed with Dr Wong the gap between the gap between Claim 1 and as far as he had managed to get from LG 434 in conjunction with the CGK and his (allegedly) obvious steps.[433]Dr Wong confirmed that there remained 3 missing pieces [T2/143/15-24]: i) a PBCH which has a bandwidth which is wider than the PSS and/or SSS; ii) to frequency interleave the DMRS with the PBCH; and iii) a MIB – or Master Information Block on the PBCH.

The Master Information Block - MIB

[434]During cross-examination Counsel for Samsung pointed out that the MIB is a feature which an expert, operating without any hindsight, would have had no real reason to mention on the journey thus far from LG 434. It nevertheless occurs in the claim and Samsung accepted that Pozzoli is a useful tool to bring its existence to the expert’s attention, to enable them to ask the question whether adding the feature would “constitute a step which would have been obvious to the person skilled in the art or … require any degree of invention”.[435]Samsung accepted that the MIB is something which was CGK and would have been obvious to carry on the PBCH. Indeed, it was present in LTE (on the PBCH). Accordingly, Samsung made no criticism of Dr Wong’s approach to the MIB in ¶444 of his first report.[436]However, Samsung’s position on the other two integers, discussed below, was different. Having been instructed to include a separate stage (Phase 2) which addresses the course which would be obvious to the Skilled Person outside of the Pozzoli framework, Samsung contended it is not appropriate to ‘have another go’ from within the framework. In such circumstances, Samsung submitted that the framework is properly only applied to ensure that the expert has not missed the obvious because, unlike a real person, the notional skilled person never misses the obvious. However, Samsung contended that Dr Wong’s approach to the other two missing integers was simply to have another go at further development which would never have occurred to his Skilled Person.

Interleaved Frequency Division Multiplex of the DMRS and PBCH

[437]Interleaved Frequency Division Multiplex of the DMRS and PBCH ZTE’s contentions ZTE submitted it would be obvious for the Skilled Person taking the Proposal 2 idea forward to IFDM the signal into the PBCH. ZTE maintained this was the case whether the Skilled Person went to the Ad Hoc Meeting report or not.[438]Dr Wong explained that the Skilled Person would want to better understand what the additional signal of proposal 2 could be and how a PBCH demodulation signal could be implemented. He said that they would want to check what had already been agreed in RAN1 meetings on this point to the extent they could not recall them, and explained that the most recent agreement on such matters was to be found in the Ad Hoc meeting report. See Wong 1 §§207-209. Mr Anderson accepted that Dr Wong’s skilled person would take that course (though he suggested that his skilled person would not) – [T3 318/6–319/14]. He also accepted that a skilled person wanting to look at the report of the Ad Hoc meeting would have looked at the final report (which had been published by the Priority Date) rather than the draft report (or “Chairman’s Note”) that was cited in LG 434 – see Anderson [T3 315/14–316/14].[439]Dr Wong identified as most relevant the agreement set out in Wong 1 §208 and Mr Anderson did not identify any other agreements of relevance [T3 319/15-25]. That agreement identified three options. The first was “Synchronisation Signal (e.g. NR-SSS)”, the second was “Self-contained DMRS” and the third was MRS, if supported. It was common ground that by the Priority Date it had been agreed that the function of the MRS would be fulfilled by SS and/or DMRS, so the third option added nothing to the other two – see Wong 1 §215, Anderson 2 §71 & [T3 325/8–326/6].[440]Dr Wong explained that option 2, the “Self-contained DMRS”, would be understood by the Skilled Person as meaning a DMRS which was multiplexed into the REs of the PBCH, and that would be regarded as a good option as it would give good channel estimation properties due to its close proximity in time and frequency to the PBCH REs – Wong 1 §§211 & 214. He explained that IFDMing the DMRS into the PBCH would be the most obviously advantageous way of implementing that – see Wong 1 §§445-446 and also §407.[441]ZTE argued that Dr Wong was not actually challenged on his evidence that the most obviously advantageous implementation was an IFDM arrangement. His XX on this topic was at [T2 146/14–157/22]. ZTE submitted that the vast bulk of that passage of XX was about whether Dr Wong had been right, in his §446, to describe frequency multiplexing the DMRS in the same symbol as the PBCH as being “in the same way as the CRS was multiplexed in the PBCH (and various other channels) in LTE”. ZTE sought to sideline this point by saying whether that comparison was completely apt or not is not (and never was) the point. The point is that Dr Wong’s evidence was that IFDM was an obvious implementation, and that was not challenged.[442]On this point, ZTE submitted that Mr Anderson’s view was that a “Self-contained DMRS” in fact implied an IFDM arrangement – see Anderson 2 §68 & [T3 320/25–322/11].[443]Next, ZTE submitted there was a debate about how the skilled person would understand option 1, the “Synchronisation signal (e.g. NR-SSS)”. Dr Wong had taken the view that the skilled person would regard this as proposing the SSS, which would not appeal to the skilled person who had read LG 434 and was looking for an additional signal rather than the SSS – see Wong 1 §213. In XX he was taken to RAN1 documents relating to a potential TSS and then agreed that option 1 encompassed a TSS, which would be an additional signal – see generally [T2 115/14–125/15]. Mr Anderson’s position, by contrast, was that option 1 did not include a TSS – see [T3 320/2-24].[444]On this point ZTE submitted that it does not matter whether the skilled person would have thought of a TSS when considering option 1. First, the skilled person is still presented with the option of a self-contained DMRS i.e. a DMRS IFDMed into the PBCH. Secondly, it would still have been obvious to IFDM a TSS into the PBCH (for the same reasons), and that would be within claim 1 – as the Patent makes clear in [0201], it does not matter what name you give to the signal (you can call it a DMRS or a TSS, amongst other names).[445]While the point had hardly been clear from his first report (see Anderson 1 §§315-316), in his second report Mr Anderson took the position that while it would be sensible to IFDM a signal intended solely for channel estimation into the PBCH, that would not necessarily follow if the signal was also intended to carry information (Anderson 2 §114 and [T3 324/10–325/4]); he said that would depend on how much information it needed to convey, the required reliability and how it is to be detected. However, ZTE argued that none of the points made by Mr Anderson in his §114 were put to Dr Wong.[446]ZTE relied on how the XX of Mr Anderson on this topic concluded: [T3 343/9–344/16]:
‘Q. Can I just put this to you, Mr. Anderson. For a signal that is going to be used for channel estimation also to carry information by the choice of sequence from a number of hypotheses, I would suggest that IFDMing it with the channel which it is being used to demodulate would have been one of the obvious options for the skilled person and which would have been the best option would depend on the technical analysis. A. I do not know whether the skilled person would have immediately considered IFDM for that additional signal. As I say, I think that partly depends on what the objectives of that signal are, how many bits it would need to carry, how it relates to the other signals within the block and whether or not there are already DMRS that will be present for PBCH demodulation. Q. However, if you are introducing a signal for PBCH demodulation, this additional signal, one of the obvious ways of, perhaps the most obvious way of implementing a demodulation, a signal for demodulation is to IFDM it with the signal that it is going to demodulate; yes? Just think about the demodulation --- A. Demodulation, I have made that clear. Q. Yes. If you are going to introduce a signal for demodulation one of the obvious things that is going to come to the skilled person's mind is IFDMing it, yes? A. For demodulation, yes. Q. Then the question they have to consider is does that remain a preferred option, given it also has to carry information? A. Yes. Q. You have made it clear that that will depend on a detailed technical analysis. A. It would.’
A. It would.’[447]So, ZTE concluded, even if there was anything in Mr Anderson’s points (and they maintained they were not put to Dr Wong) they do not go anywhere. The skilled person would think of IFDMing a PBCH demodulation signal into the PBCH (whether because they have read option 2 in the Ad Hoc meeting report or otherwise). Mr Anderson says they would then need to consider whether that remains a preferred option given that the signal also has to carry information, which requires a detailed technical analysis. ZTE’s response was that the Patent does not contain any such technical analysis, as Mr Anderson agreed [T3 269/3-17]). Thus, ZTE said that Samsung cannot rely on concerns about IFDMing an information-carrying signal into the PBCH without showing that such concerns are misplaced – citing the case law I have set out at [376]-[380] above.

Samsung’s contentions

[448]Samsung’s contentions On this feature, Samsung contended that, as with every other aspect of the claimed invention, Dr Wong’s treatment of IFDM (at Wong 1 [446]) jumped directly to selection of the claimed solution (emphasis added):
‘446. While the DMRS could be located in an adjacent OFDM symbol, the Skilled Person would understand that it would work most effectively if it was frequency multiplexed in the same OFDM symbol as the PBCH, in the same way that the CRS was multiplexed in the PBCH (and various other channels) in LTE [his fn referred to Fig 17, which I have included above under [160]]. As such, I consider the most obviously advantageous way of implementing this would be to multiplex the DMRS in the PBCH with DMRS REs evenly spaced throughout the bandwidth to provide channel estimation across the wide bandwidth. I therefore consider that ‘IFDM-ing’ the DMRS (as EP 154 refers to it) would be an obvious implementation of a ‘self-contained’ reference signal.’
[449]Dr Wong was challenged on this justification and the following points emerged: i) First, Samsung pointed to the cursory mention of one other option which existed. ii) Second, Samsung pointed out that the arrangement of the CRS in LTE is cell-wide: it is not deliberately interleaved in the PBCH. For this reason, Counsel put to Dr Wong that, if you were not trying to make LTE look like 5G, you would not describe the CRS as he had done in his [446]. Dr Wong accepted that, with the CRS it was, in effect, IFDM’d across the system such that the Skilled Person would describe the CRS in LTE as being a system-wide reference signal spaced in time and frequency. Dr Wong struggled to see the problem, but eventually he accepted the whole of the CRS is not frequency multiplexed with the PBCH. iii) Dr Wong also accepted a further point: that for finding a channel estimate from the CRS for use in decoding the PBCH, the CRS REs that would actually be used were not just the ones running through the middle of the PBCH, but rather those and the CRS either side of the PBCH (which clearly are not interleaved with the PBCH) [T2/150/8-151/13] (See also his general acceptance of how CRS is used at [T2/67/14-22]). iv) Third, at this point, Dr Wong appeared to fasten on the words in brackets and mentioned, for the first time, the PDSCH transmission mode and that it also was IFDM. He explained this reference on the basis that ‘there are actually DMRS that are actually dedicated for a channel, such as the PDSCH transmission, IFDM…’ indicating that the use of IFDM is one way of doing channel estimation. As Samsung submitted, this had never been raised by either of the experts (see [T2/149/12-157/22] and, in particular, [T2/157/12-22]).[450]In the light of this evidence, Samsung submitted that Dr Wong’s abandonment of the CRS (which is indeed multiplexed with various other channels beyond the PBCH as his evidence appeared to say) and attempt to retreat to an actual DMRS which had never previously been mentioned was unfortunate. They also pointed out that it was not supported by any proper explanation in the case, and quite notably, was not put to Mr Anderson when he gave his evidence the following day.[451]Samsung therefore submitted that there was no actual support for Dr Wong’s Skilled Person alighting upon IFDM by analogy to anything in the CGK, notably LTE. Nor, they said, was there any evidence justifying the rapid dismissal of the adjacent OFDM symbol approach mentioned by Dr Wong in his [446]. The only reason given in Wong 1 was that the Skilled Person would think the IFDM option was “most obviously advantageous”, but that of course depends upon the Skilled Person having the idea in the first place, which Samsung contended was never properly established.[452]Samsung also noted that, as part of his reasoning in [446], Dr Wong also referred to the IFDM’s DMRS being advantageous “across the wide bandwidth” but that at this point in his evidence he had not addressed the bandwidth of the PBCH. Moreover, the IFDM’d bandwidth would be no different to that of an adjacent DMRS (with which he was comparing it), and Mr Anderson explained in cross-examination that moving to a 1-in-K interleaved DMRS would, in fact, reduce the effectiveness of the DMRS [T3/333/18-335/11].[453]On the basis of these points, Samsung submitted as follows: i) First, that, in all the circumstances, Dr Wong’s ‘obvious to adopt IFDM for the DMRS’ position was entirely unsupported by any credible evidence as to what his Skilled Person would in fact have thought, without hindsight, at the Priority Date. ii) Second, that Dr Wong’s Skilled Person was only motivated to start thinking about the feature at all after it had been placed on a pedestal by Pozzoli, having already failed to alight upon it after setting out what would have been obvious in the light of LG 434. iii) Third, the reasons given for even thinking of IFDM proved to be an unconvincing attempt to alight on something that looked a little like IFDM in LTE, but which was rightly abandoned once the true technical function was explored in cross-examination. iv) Fourth, Dr Wong’s belated reference to some other DMRS that existed in LTE (and hence would have been CGK), but which was never mentioned as being relevant by either expert, cannot properly assist ZTE.[454]Samsung’s final point was that, even if IFDM had occurred to the Skilled Person (which they did not accept), Dr Wong’s failure properly to justify choosing between IFDM and other options such as a single adjacent OFDM symbol, or multiple adjacent OFDM symbols (which he accepted was also a possible approach [T2/148/25-149/11]), did nothing to support ZTE’s case. At the very best it was yet another ‘option’ on the path from LG 434 to Claim 1.

Analysis

[455]Analysis I have considered carefully the passage of cross-examination cited by ZTE in [441] above. In that passage Counsel was very clearly challenging the reason which Dr Wong had put forward and the basis for his contention that IFDMing the DMRS into the PBCH was the most obviously advantageous way of implementing this feature in the claim.[456]As to ZTE’s point in [447] above, I did not understand Samsung to argue, whether on this point or any other, that the Skilled Person would have any concern or prejudice against any of the features in the claim. Instead, Samsung appeared to me to make a fairly consistent point against Dr Wong’s analysis – that he jumped to the solution he knew was in 5G, without giving any or any proper consideration to the other options which the Skilled Person would have faced. Samsung’s additional point was that some form of technical analysis would have been conducted by the Skilled Person in order to choose between the options.

Wider bandwidth of the PBCH

[457]Wider bandwidth of the PBCH Although both sides focused on [447] of Wong 1, on this point it is convenient to set out Samsung’s contentions first and then turn to ZTE’s.

Samsung’s contentions

[458]Samsung’s contentions Samsung focussed on Dr Wong’s reasoning on this feature which was contained in his [447]:
‘447. The OFDM symbol would need to accommodate the DMRS resource elements in addition to the PBCH resources, which would suggest a wider bandwidth than the PBCH would otherwise have had on its own. However, the Skilled Person would not know whether using a self-contained DMRS would necessarily result in a wider bandwidth than that of the PSS or SSS, as this would also depend on parameters such as the amount of information to be transmitted on the PBCH, the number of OFDM symbols used, the chosen DMRS overhead and the number of REs allocated to the PSS and SSS. None of these parameters had been agreed by PD1. However, one obvious option would have been for the PBCH to have a wider bandwidth than the PSS or SSS. Indeed that was the position in LTE. The Skilled Person would also consider it obvious that the PBCH bandwidth could have been narrower than (or the same bandwidth as) that of the PSS/ SSS if it was ultimately decided that less information needed to be transmitted.’
[459]Samsung contended that, in summary, what Dr Wong appeared to be saying was that if the PBCH was of a certain bandwidth, adding IFDM would add resource elements and, thus, the bandwidth would be wider. Samsung submitted that that was the only justification provided by Dr Wong in his written evidence, and even then, Dr Wong made clear that whether that would be wider or narrower than the PSS/SSS would depend upon a multitude of choices as to the three channels.[460]In cross-examination, Dr Wong accepted the following points: i) First, that the mathematical PBCH+DMRS must have a wider bandwidth contention was wrong – the result of adding DMRS (even on a simplistic approach) leads merely to a requirement for more REs, not a requirement for more bandwidth [T2/159/25-160/16]. ii) Second, that the CGK approach to a need for more REs for the PBCH than for each of the PSS & SSS in LTE was to allocate more symbols to the PBCH, not to allocate more bandwidth [T2/159/17-24]. iii) Third, that his premise of adding DMRS leading to a ‘bigger PBCH’ did not really hold: precisely what would be required in terms of resources for the PSS, SSS and PBCH/DMRS depended on a large number of variables which were wholly unknown at the Priority Date (see generally [T2/161/12-162/9]).[461]Having established those points, Counsel then put to Dr Wong that his suggestion in [447] that the addition of the DMRS would lead to wider bandwidth could only have been led by his knowledge of the bandwidth requirement of the claim and that there is no other reason for his Skilled Person to even think about a wider bandwidth. Dr Wong suggested that there might have been a thought in 5G that it was advantageous to keep the time duration of the overall SS Block as short as possible, which would suggest minimising the number of PBCH symbols, favouring a wider bandwidth instead [T2/162/10-164/23]. However, he accepted this was not something which had occurred to him prior to cross-examination [T2/164/24-165/8]. Samsung submitted his answer was not good evidence of what the Skilled Person would have thought about without hindsight. It was subsequently put to Mr Anderson as a potential consideration, with which he rightly agreed, [T3/349/22-351/15] but Samsung’s point was that establishing that such an afterthought (occurring only during the course of trial) may be a technically relevant matter for consideration does not speak of obviousness.

ZTE’s contentions

[462]ZTE’s contentions On this feature, ZTE relied on Dr Wong’s explanation that the choice of bandwidths for both the PBCH/DMRS and the PSS and SSS would be a routine design choice taking into account factors such as the resources which need to be allocated to them and how those resources can be distributed in time and frequency – see Wong 1 §407 (relying in part on paragraphs incorporated into the Agreed CGK – see [137]-[138] above – plus a paragraph where he said design decisions regarding the allocation and positioning of REs were ones that the Skilled Person would routinely make, bearing in mind the factors identified in those paragraphs). One obvious option would be for the PBCH/DMRS to have a wider bandwidth than the PSS or SSS – Wong 1 §447.[463]As before, ZTE developed an argument which had not been put forward by Dr Wong and which sought to rely heavily on answers secured from Mr Anderson. The end point of this argument was that there was every reason for the bandwidth of the PBCH/DMRS to be wider than those of the PSS and/or SSS.[464]The argument was developed as follows: i) First, Mr Anderson’s acceptance that the bandwidth feature (on its own) was not inventive [T3/305/16-22] ii) Second, his agreement in his second report with Dr Wong’s evidence on the factors involved, albeit he disputed the design choices involved were routine. His view was that they involved complex trade-offs in an evolving standard. In cross-examination he explained that he was referring to the fact that there were things left to be developed, which happened after the Priority Date, and that the Patent did not address such matters [T3/344/17–345/18]. iii) Third, Mr Anderson agreed that the skilled person would always have to consider the allocation of time and frequency resources to signals and channels. He also agreed that there was no reason to assume that the allocation would be the same in NR as it was in LTE, and that it would need to take account of changes in the available resources in NR, such as increased system bandwidths, and the objectives of NR such as reduced latency. See Anderson [T3/304/23–305/15]. iv) Fourth, Dr Wong and Mr Anderson agreed that in LTE it had been necessary to use four symbols for the PBCH given the size of the smallest system bandwidth (1.4 MHz, or in practice 1.08 MHz or 6 RBs). The PBCH had been confined to that bandwidth even in the larger system bandwidths of LTE because it was necessary to use the same PSS/SSS/PBCH arrangement in all cases because during initial access the UE does not know what system bandwidth is being used. See Wong [T2 68/14–70/6] and Anderson [T3 216/3–217/7], each giving evidence on [CXX-SHW/6 p.162]. v) However, in NR the smallest bandwidth was 5 MHz (with the same 15 kHz sub-carrier spacing as used in LTE) – see Anderson [T3 346/15–347/16] wrt [D2.2/7 p.644]. Further, the NR PBCH payload would be within a factor of two of the payload of the PBCH in LTE – Anderson [T3 349/7-18]. Moreover, in NR the UE could be required to decode multiple SS blocks with different PBCHs and reducing the number of symbols used for the PBCH would reduce the duration of the SS blocks and accommodate more within a given period – Wong [T2 160/17–161/7 & 163/8–164/23], Anderson [T3 226/2–227/2 & 349/19–351/10]. The upshot, according to ZTE, lies in these answers given by Mr Anderson [T3 351/11-19]):
‘Q. So there would be, there was both the opportunity and the incentive to reduce the number of symbols allocated to the PBCH in each SS-block and increase the bandwidth of the PBCH in the frequency domain. A. I do not think that is unreasonable. Q. In fact, you could use essentially the whole of the 5 MHz bandwidth available to the PBCH? A. Again, this is the PBCH bandwidth they are considering, not the system bandwidth.’
A. Again, this is the PBCH bandwidth they are considering, not the system bandwidth.’ vi) There is then a separate decision to be made about the bandwidths that would be needed for the PSS and the SSS. Mr Anderson agreed that those bandwidths would depend on how many hypotheses those signals needed and hence their sequence length [T3 351/20-25]. In LTE both signals had a bandwidth (including guard bands) of 1.08 MHz. The targeted increase in the number of cell IDs in NR might increase the sequence lengths somewhat but there was no reason to think they would increase five-fold. See [T3 352/16–353/13], concluding:
‘Q. You may have to double the amount of hypotheses, so that means you may extend the sequences slightly, but you are not going to make it five times greater? A. There is logic to what you are saying.’
[465]On this basis, ZTE submitted there was every reason for the bandwidth of the PBCH/DMRS to be wider than those of the PSS/SSS. ZTE also pointed out that RAN1 had envisaged that might well be the case, relying on D2.2/7/p651, where in the RAN1 Minutes for the 88bis meeting, for a series of four parameter sets on subcarrier spacing and possible maximum transmission bandwidth, the agreement was, for each parameter set, to study whether transmission bandwidth for NR-PBCH is the same or wider than that of the NR-SS. On this point Mr Anderson agreed that RAN1 had in mind that a quite possible outcome was that the PBCH would have a wider bandwidth than those of the synchronisation signals [T3/255/2-10].

Analysis

[466]Analysis ZTE’s argument is beguiling, but caution is required when one is dealing with an allegation of obviousness. I bear in mind the following circumstances: i) First, that, in the usual way, Dr Wong’s written evidence will have been very carefully prepared with the assistance of experienced lawyers, putting forward what Dr Wong considered to be the best case of obviousness. ii) Second, having considered all the written evidence in the lead up to trial, and having seen what transpired during Dr Wong’s cross-examination, Counsel for ZTE was able, on certain issues, to suggest a particular step was obvious on reasoning different to that explained by Dr Wong in his evidence. iii) On that basis, securing answers that something is ‘not unreasonable’ and that there is ‘logic to what you are saying’, when the cross-examiner knows precisely the target, is not necessarily the best evidence of obviousness, particularly when the particular train of reasoning does not appear in the opposing expert’s report.[467]Reverting to Dr Wong’s reasoning, that too was far from convincing, in my view. It struck me as a thought process divorced from what the Skilled Person would be thinking. It is difficult to see how or why the Skilled Person would reach a conclusion on bandwidth without taking into account all the other considerations which would bear on the matter, in particular, what other signals would be carried on the PBCH. It is true, as ZTE pointed out to Mr Anderson, that the Patent does not address any of those matters either. It is also true that Dr Wong was not saying anything other than having a wider bandwidth was one of the obvious options open to the Skilled Person.

Standing back – the ‘long journey’ from LG 434 to the Claims

[468]Standing back – the ‘long journey’ from LG 434 to the Claims Samsung’s contentions Having made all the points I have discussed above, Samsung then invited me to stand back to survey the overall ‘journey’. Samsung accepted that some of the individual steps are bigger and more important than others, as is inevitable with a ‘Technograph list’.[469]Their point was they are nevertheless all steps which form part of a long journey to Claim 1 of the Patent starting from what they characterised as a single-sentence conditional second proposal in an TDoc that was left untreated (i.e. not discussed) at the RAN 1 meeting to which it was submitted. Samsung made the following observations: i) First, the set-up for Dr Wong’s evidence produced a real risk of subconscious hindsight from the outset. As discussed above, he knew every element of Claim 1 and their interaction before he was even contacted about this case yet did not acknowledge the same in the formation of his evidence, nor did he “reflect carefully” on how that knowledge might influence his views. ii) Second, the further set-up of Dr Wong’s evidence produced a real risk of conscious hindsight. This was Samsung’s argument that two very significant parts of the journey had to be conducted under the Pozzoli framework (which inevitably consciously spotlights the ‘missing pieces’ for the expert), in this case, after they had expressly not been reached through the ordinary development of the prior art. iii) Third, there are numerous examples of Dr Wong’s decision at individual steps going immediately in the direction of the claim with very little genuine hindsight-free analysis supporting the selection. None was attempted at all in Phase 1 (to select a single pursuit of a narrow reading of Proposal 2); no explanation was given for not considering, still less pursuing the TSS or rejecting the MRS in Phase 2; and the two points in Phase 3 where characterised by attempting to say that IFDM looks somewhat like CRS (without recognising it is technically different), and that increased bandwidth is a mathematical inevitability from having more REs (whilst ignoring the CGK as to how a need for additional REs was conventionally accommodated). iv) Fourth, and allied to the previous point, at no stage did Dr Wong’s Skilled Person see the need for, still less pursue, any mathematical analysis or simulations to verify the suitability of a selected alternative. This was the case notwithstanding that he readily accepted that the Skilled Person would routinely use them, for example, for Proposal 1 in LG 434 [T2/108/16-23]; for sizing the PBCH [T2/111/18-112/25]; for considering the feasibility of SSS/TSS for carrying SSB Index (in CXX-SHW/7) [T2/169/20-170/21]; for considering the feasibility of SSS/DMRS for demodulation of the PBCH (in LG 438) [T2/188/7-189/23]; and generally if his Skilled Person was to have any hope of submitting his overall solution to RAN1 [T2/167/20-168/10]. As Samsung submitted, the need for simulations in the obviousness journey is different to the need for simulations in the Patent. a) The former are required to establish that the Skilled Person would make the requisite choices between potential options at each stage – a justification is required for taking a particular step, and if (as Dr Wong generally accepted) the Skilled Person would conduct experiments to guide their development in the real-world, there is no warrant for dispensing with them in the course of litigation. b) As to the Patent, the decisions have already been taken and the overall solution laid out: it only needs experiments to the extent that the Skilled Person would not consider it plausible without support – as to which, no such allegation has ever been advanced. v) Fifth, the need for firm justification for Dr Wong’s Skilled Person taking the necessary sequence of steps (as discussed in the previous point) appeared during cross-examination to be something which Dr Wong did not appreciate. Rather, he appeared to have understood that it was sufficient for the purposes of his evidence simply to say that the particular option is one that could be taken, or was reasonable to be taken, rather than that it would be taken. This started with his approach to Proposal 2, simply assuming that the Skilled Person would seek to put it into effect, rather than considering whether it was a proposal that the Skilled Person would have a technical reason for putting into effect [T2/113/22-113/15]. Dr Wong confirmed that this was his approach to the journey throughout LG 434 in terms [T2/138/20-139/5]:
‘Q: Let me see if I can put it -- Let me see if I can give it to you again. Your process of going from 434 through your evidence, at each stage, the question you have been asking yourself is not, "Would the skilled person choose, for the purpose of 5G, this option" and then move on to the next stage on the basis of that option, which definitely has been taken. What you are rather doing is looking at each stage and saying, "This is one of the options that could be taken." Is that fair? A: It could be taken; yes.’
A: It could be taken; yes.’ vi) Sixth, Dr Wong’s own failure to ‘stand back’ at any point in his Skilled Person’s journey. Samsung picked this up with him at the end, reminding him that his Skilled Person only adopted Proposal 2 of LG 434 on the basis that there was not enough space on the PBCH for the SSB Index; but yet by the end of the journey, the Skilled Person was left expanding the bandwidth of the PBCH anyway. He confirmed that his Skilled Person simply never ‘stood back’ and questioned whether they were actually achieving anything useful, despite accepting that it would have been a reasonable question. See [T2/165/9-167/19]. vii) Seventh, the sheer length of the journey, taken in 3 phases, is exceptional. There are numerous steps, few of which (if any) can confidently be said to have been: (a) firmly taken – as opposed to being ‘options’; or (b) clearly free of hindsight.[470]In light of those observations, naturally Samsung relied on Floyd J’s (with the approval of the Supreme Court) emphasis on the need for the Court to ‘stand back’ at the end of the journey and take a holistic view. In addition to the matters set out above, Samsung also relied on, effectively, all the points they made earlier on the nature of the Skilled Person and their CGK: i) the journey is already being taken by an exceptionally focused Skilled Person (assuming they are, contrary to Samsung’s position, a valid skilled person in an ‘established field’); ii) the alleged ‘CGK’ is of a very unusual nature, in that ‘options’ within RAN1 minutes do not themselves set out a number of widely-accepted techniques from which the skilled person is free to select (e.g., nailing, screwing, gluing), they are potential options, only one of which (if any) is valid for Dr Wong’s Skilled Person, but they know not which; iii) Dr Wong’s Skilled Person is ‘RAN1 Bound’, in that they are only prepared to do something which would lead to a proposal which would be suitable for submission to RAN1 [T2/85/8-86/8], but Dr Wong readily accepted at the end of his obviousness Journey that the solution which he had reached could not hope to be accepted by RAN1 without being properly backed-up by technical results showing the practical effects of how all the various components and decisions interact [T2/167/17-168/7]; and iv) Finally, the alleged obviousness case is unusual in that, if Dr Wong is right, his Skilled Person, as closely as possible, is constructed to typify the sub-set of RAN1 participants specifically working on the design of the SS Block for 5G. Unlike many cases in which it cannot be shown that all those in the real world who might typify the skilled person were shown the cited prior art, in the present case we do know that RAN1 was given LG 434. Nevertheless, RAN1 did not alight upon the Patent’s solution even by the time it finished its Study Item. As Dr Wong accepted in cross-examination, the final version of TR 38.802 does not include the material elements of the invention [T2/197/2-24].[471]Accordingly, Samsung submitted that, fairly assessed, the Patent is anything but obvious in the light of LG 434, even giving ZTE the benefit of the very focused skilled person and attendant CGK upon which they rely.

ZTE’s contentions

[472]ZTE’s contentions I have described ZTE’s contentions on the individual Samsung steps above. Here I consider ZTE’s overall contentions, in response to Samsung’s ‘standing back’ arguments. As befits any obviousness argument, ZTE’s argument was simple and straightforward and brushed aside any of the obstacles which Samsung relied upon.[473]ZTE submitted that: i) The case of obviousness over LG 434 was very straightforward, not least because there was very little dispute between the experts following cross-examination. ii) In Samsung’s submissions, there was a general lack of recognition of the effect of Mr Anderson’s evidence, because, following cross-examination, there was very little left in dispute between the experts. iii) It was pointless to dwell on what they called ‘the archaeology’ of all the alleged decisions. iv) There were really only three points between the experts: a) The first concerned Mr Anderson’s view that the Skilled Person would have wanted to see a simulation, a technical analysis to decide whether the Proposal 2 idea was better than/preferable to, alternative approaches. Mr Tappin submitted that did not make it inventive to take Proposal 2 forward and implement it. b) The second concerned implementation. On that, Mr Tappin submitted(i) it was common ground that the most obvious way of doing Proposal 2, so that you could indicate the SS block index using the signal, was to use a sequence and(ii) it was common ground that the Skilled Person would think of IFDMing the signal with the PBCH in order to achieve demodulation. He was dismissive of Mr Anderson’s answer in Anderson 2 [114], which he said was not put to Dr Wong. c) The third concerned the bandwidth issue. On that Mr Tappin submitted [T4/437]:
‘…the choices of bandwidth for the various channels and signals suggest independent design choices and, in any event, there was the incentive and the opportunity in NR to make the bandwidth of the PBCH wider and for it to end up wider than the PSS or the SSS.’

Analysis

[474]This is a case where the ‘standing back’ stage is crucially important because in many respects the arguments are very evenly balanced, and in such a situation small points may matter. For this reason, I have given careful consideration to the points which have particularly weighed with me in favour of and against a finding of obviousness.[475]Overall, however, I have eventually come to the conclusion that claim 1 was not obvious over LG 434 on the evidence I received. Since this is a multi-factorial assessment and it is difficult in a case of this nature to specify every point which has influenced me, I set out here the principal points which I have had in mind.[476]Although, in my view, Samsung overplayed their hand in certain respects (stage 1 of their ‘journey’ in particular) which I leave out of account, having stood back and surveyed what I regard as the valid steps in ZTE’s obviousness argument, I was left with the impression that Dr Wong had not given sufficiently convincing reasons for taking some of his steps and/or some of his reasoning was artificial. Particular points I have in mind are the following.[477]On the IFDMing of the PBCH and DMRS integer, I did not find Dr Wong’s justification based on the CRS in LTE convincing. Knowing of the solution in 5G one can just about see the analogy with the CRS, but that seemed hindsight reasoning to me. Equally, his stray reference to ‘the wide bandwidth’ when discussing this feature and when he had not yet addressed the bandwidth feature was another indicator of hindsight.[478]On the wider bandwidth integer, I agree with Samsung that his reasoning based on PBCH+DMRS must have a wider bandwidth was technically incorrect. I also bear in mind that a similar point might be suggested in the first sentence of [0204] in the Patent. In addition, it seems to me that the Skilled Person would have had to have considered a whole host of variables (e.g. at least those also mentioned in [0204]) before reaching any conclusion as to the bandwidth required for the PBCH (see also e.g. [137] above), and Dr Wong simply did not consider that. There also seemed to be an inconsistency in his reasoning. His Skilled Person adopted Proposal 2 on the basis that there was insufficient space on the PBCH for the SSB Index. Yet, later in his analysis his Skilled Person is left expanding the bandwidth of the PBCH beyond that of the PSS or SSS.[479]More generally, Samsung exposed some errors in Dr Wong’s reasoning. I have in mind the points summarised above at [408] & [409] and his acceptance of the point mentioned in [426], which meant that the underlined phrase in [7] of his Third Report was not correct.[480]The lack of sufficient or convincing reasoning combines with the risk of hindsight. Again, Samsung overplayed the hindsight arguments in certain respects, but I was left with the impression that hindsight was a factor in several of Dr Wong’s steps.[481]In this regard, it is of some significance that Dr Wong appears not to have been instructed in accordance with the guidance in Fisher & Paykel. It makes a difference if an expert has identified how they knew about the invention and when and has reflected carefully on how that might influence them, and disciplined themself carefully to avoid hindsight, but there was no indication that Dr Wong had taken those steps, and he confirmed in cross-examination that he had not.[482]On these points, ZTE’s only real answer was an attempt to brush aside what they called the archaeology of the required decisions. However, the archaeology is critical – it engages the reasons put forward as to why individual choices and the overall journey were said to be obvious.[483]As to the could/would distinction, I am not at all sure that Dr Wong understood the significance of the point put to him (see the extract from his cross-examination in [469.v)] above) and if this had been the sole point against obviousness, I might well have discounted it. However, in line with the other points listed here, his answer is consistent with both the lack of sufficient reasoning and a degree of hindsight reasoning.[484]I was acutely aware of ZTE’s Brugger v Medicaid argument that each of the choices made by Dr Wong was essentially a choice between options, each of which was obvious. That point, however, seemed to me an attempt to bolster Dr Wong’s reasoning beyond the reasons he actually identified in his evidence.[485]I was also aware that Dr Wong had to write a very long first report. If the issues had narrowed earlier, it might have been the case that his reasoning in his written reports might have been fuller and more convincing. Against that, however, is the fact that, whether in his Second or Third Reports or in cross-examination, Dr Wong had plenty of opportunity to explain his reasoning further and, as I indicate here, it fell short in my view.[486]So far as Mr Anderson’s evidence is concerned, it is true, as ZTE stressed in closing, that Mr Anderson did not, in terms, state that the invention was not obvious, but that misses the point that the burden lies on ZTE to persuade me that it was. Furthermore, although Mr Tappin secured answers from Mr Anderson indicating that particular steps were obvious, it seems he did not dare to put the critical point to him that the whole ‘journey’ from LG 434 to claim 1 was obvious.[487]I should also draw attention to the fact that I analysed the obviousness arguments using Dr Wong’s Skilled Person and his account of the CGK, giving every advantage to ZTE’s arguments.[488]In the light of my conclusion on this issue, it is not necessary to address the point I left over from [316] above. Suffice to say that if I had been persuaded the features in Integers B, C and D were obvious, Samsung’s UE point would not have saved the Patent.[489]Accordingly, in the light of all the evidence and arguments presented to me, I find that the Patent was not obvious over LG 434.

ALLEGED COLLOCATION

[490]ALLEGED COLLOCATION Applicable Legal Principles On this topic, both sides made reference to the well-known authorities but again chose to emphasise different particular passages.[491]In terms of the generally applicable principles, ZTE referred to the review of the law by Arnold LJ in Illumina Cambridge v Latvia MGI [2022] R.P.C. 14 at [157]-[169]. In that case, the Court reaffirmed the established principle that a valid patent claim cannot comprise a mere collocation of features each of which is old or obvious. Arnold LJ’s summary of the law was as follows:
“158. In Williams v Nye (1890) 7 R.P.C. 62 the patent was for a sausage machine that was a combination of a known mincing machine and a known skin-filling machine. Kekewich J. held that the patent was invalid, and his decision was affirmed by the Court of Appeal on the ground that, although the claimed machine was new, it was not inventive. 159. In British Celanese Ltd v Courtaulds Ltd (1935) 52 R.P.C. 171 the main patent was for a process of manufacturing artificial silk. Clauson J. held that the patent was invalid, and his decision was affirmed by both the Court of Appeal and the House of Lords. In the House of Lords it was common ground that the patented process consisted of four features, each of which was old. Lord Tomlin set out at 193 the legal proposition relied upon by counsel for the plaintiffs: Lord Tomlin evidently agreed with this statement of the law, but he rejected the plaintiffs’ case on the facts at 194: 160. In SABAF SpA v MFI Furniture Centres Ltd [2004] UKHL 45, [2005] R.P.C. 10 the patent was directed to burners for separate gas hobs which took up as little vertical space as possible. In gas cookers and hobs the gas had to be mixed with air before it was ignited in order to burn steadily. In addition, the pressure of the gas had to be sufficient to expel it through the holes in the burner in a steady stream. In gas cookers both requirements were met by the use of a tube which passed horizontally below the hob and then turned upwards to connect with the burner. The tube had an air inlet. It also had a slight flare which, by virtue of the Venturi effect, increased the pressure of the mixed gas and air. The disadvantage of this arrangement was that it took up vertical space. The invention achieved a more compact hob by an arrangement in which both the air intake and the Venturi effect took place above, instead of below, the hob. 161. At trial Laddie J. held that: “It is accepted as sound law that a mere placing side by side of old integers so that each performs its own proper function independently of any of the others is not a patentable combination, but that where the old integers when together have some working inter-relation producing a new or improved result then there is patentable subject-matter in the idea of the working inter-relation brought about by the collocation of the integers.” “In truth and in fact there is no inter-related working between the integers in the sense that any one of the integers is doing something which it could not do without the presence of one or more of the others. Each integer is fact performing its own part and is not functionally dependent upon the presence of any other integer at all. I think therefore that the invention lacks subject-matter.” “…the two important features of the SABAF burners which are said to constitute an invention are (i) drawing primary air in from above the hob unit and (ii) the use of a flow path under the flame spreader in which the Venturi effect will be present [a ‘radial’ Venturi]…there is nothing in the specification to suggest, nor has it been seriously argued, that these two features interact with each other.”
[492]The relevant passages of the current (April 2025) EPO Guidelines are as follows (and I was told, without contradiction, that they have not materially changed from those cited in Illumina or those cited in SABAF):
“Part G Chapter VII – Inventive Step […] 5.2. Formulation of the objective technical problem Sometimes, the objective technical problem must be regarded as an aggregation of several "partial problems", e.g. where no technical effect is achieved by all the distinguishing features taken in combination, but rather several partial problems are independently solved by different sets of distinguishing features (see G-VII, 6 […]) 6. Combining pieces of prior art The situation is different where the invention is a solution to several independent "partial problems" (see G-VII, 7 and 5.2). Indeed, in such a case it is necessary to separately assess, for each partial problem, whether the combination of features solving the partial problem is obviously derivable from the prior art. This means that a different document can be combined with the closest prior art for each partial problem […] For the subject-matter of the claim to be inventive, it suffices, however, that one of these combinations of features involves an inventive step. […] 7. Combination vs. juxtaposition or aggregation The invention claimed must normally be considered as a whole. When a claim consists of a "combination of features", it is wrong to argue that, viewed in isolation, the individual features of this combination are known or obvious and that "therefore" the whole subject-matter claimed is obvious. However, where the claim is merely an "aggregation or juxtaposition of features" and not a true combination, it is enough to show that the individual features are obvious to prove that the aggregation of features does not involve an inventive step (see G-VII, 5.2, last paragraph). A set of technical features is regarded as a combination of features if the functional interaction between the features achieves a combined technical effect which is different from, e.g. greater than, the sum of the technical effects of the individual features. In other words, the interactions of the individual features must produce a synergistic effect. If no such synergistic effect exists, there is no more than a mere aggregation of features […]. […] Annex […] 2. Obvious combination of features? 2.1. Obvious and consequently non-inventive combination of features. The invention consists merely in the juxtaposition or association of known devices or processes functioning in their normal way and not producing any non-obvious working interrelationship. Example: A machine for producing sausages that consists of a known mincing machine and a known filling machine disposed side by side.”

Annex

[493]In SABAF, the Court of Appeal reversed Laddie J’s decision on the basis that it was impermissible to combine two prior art citations unless it was obvious for the skilled person to do so, and Laddie J had not held that this was the case. This was reversed by the House of Lords and the relevant part of Lord Hoffman’s judgment is as follows:
“24. In my opinion the approach of the Court of Appeal is contrary to well established principles both in England and in the European Patent Office, as stated in the quotation from Lord Tomlin and the EPO Guidelines to which I have referred. I quite agree that there is no law of collocation in the sense of a qualification of, or gloss upon, or exception to, the test for obviousness stated in s.3 of the Act. But before you can apply s.3 and ask whether the invention involves an inventive step, you first have to decide what the invention is. In particular, you have to decide whether you are dealing with one invention or two or more inventions. Two inventions do not become one invention because they are included in the same hardware. A compact motor car may contain many inventions, each operating independently of each other but all designed to contribute to the overall goal of having a compact car. That does not make the car a single invention. […] 26. The EPO guidelines say that ‘the invention claimed must normally be considered as a whole’. But equally, one must not try to consider as a whole what are in fact two separate inventions. What the Guidelines do is to state the principle upon which you decide whether you are dealing with a single invention or not. If the two integers interact upon each other, if there is synergy between them, they constitute a single invention having a combined effect and one applies s.3 to the idea of combining them. If each integer ‘performs its own proper function independently of any of the others’, then each is for the purposes of s.3 a separate invention and it has to be applied to each one separately. That, in my opinion, is what Laddie J. meant by the law of collocation.”
[494]The Court of Appeal in Illumina cited with apparent approval (see [169]) the common ground that whether the claim consists of one invention or a plurality of inventions was primarily a question of what the patent disclosed, read in the light of the common general knowledge, but that evidence was admissible either to show that an interaction between features claimed in the specification did not occur or to show that an interaction not spelt out by the specification would be apparent to the skilled person or team.[495]The requirement that the interaction must either be disclosed in the specification or apparent to the skilled person is consistent with the conclusions of HHJ Birss (as he then was) in Environmental Recycling Technologies v Upcycle [2013] EWPCC 4 at [79]-[82]. Further, in that case, the judge held that any synergy relied upon must be possessed by everything falling within the claim (see [80]).[496]For their part, Samsung in their written closing highlighted three passages as being of particular interest. i) First, Birss J. (as he then was) in Illumina at [468] (which I quote below), referring to Kitchin J. in Abbott v. Evysio at first instance (emphasis added) (approved by the CA (Arnold LJ) on appeal in Illumina at [168]). ii) Second, the last two sentences of §26 from Lord Hoffmann in SABAF (quoted above). iii) Third, this passage from the judgment of Tom Mitcheson KC sitting as a Deputy Judge in Fujikura v Sterlite [2025] EWHC 3181 (Pat) at [193]: ‘I consider that collocation arguments cannot apply whenever there is an interaction between the two features which is relevant to the invention, consistent with the observations of Birss J in Illumina.’ (the paragraph continues as follows: ‘A collocation approach is only permitted where the features are truly independent, as in the example of the sausage machine.’)[497]I have found it helpful to consider the relevant passages in the judgment of Kitchin J. (as he then was) in Abbott v Evysio (these two passages also cited by Arnold LJ in Illumina): i) First, at [182]: “. . . The first step is to determine whether the claim is concerned with a single invention or not. If two integers interact upon each other, if there is synergy between them, they constitute a single invention having a combined effect. If each integer performs its own proper function independently of the others then each is a separate invention and can be considered as such for obviousness purposes.” ii) Second, his conclusion at [185] (noting that this was referred to by Birss J. at first instance in Illumina, where he agreed that the interaction was a material consideration, and by Arnold LJ on appeal at [168], with apparent approval): ‘In the light of the evidence I am satisfied that these patents cannot be considered as simply a collocation of elements which perform their own functions independently of each other. There is an interaction between them which the designer of the stent must take into consideration. Each element cannot be regarded as an individual invention for obviousness purposes.’[498]Two points arise. The minor point arose from the particular emphasis placed by Samsung on the reference to ‘the designer’ in that passage and this formed the basis for their cross-examination of Dr Wong on this aspect of the case. Thus, Dr Wong was asked to consider implementing the IFDM / bandwidth feature as a designer. However, as ZTE pointed out, the reference to ‘the designer’ in Abbott was to the skilled person (albeit, in that case, a team including an interventional cardiologist and a design engineer). This may not make much difference in this case, but it is important to identify the relevant viewpoint accurately.[499]The second point arises from the facts in Abbott from which one can gain a more precise understanding of what Kitchin J. meant by ‘interaction’. In that case, the two features of the claimed stent were the curved flexure means (which contributed to flexibility) and the flat apices (which were primarily concerned with the behaviour of the stent upon and after expansion). Kitchin J. concluded that ‘the various elements of the stent geometry do interact to some degree to produce a satisfactory balance of properties’.[500]There is a difficulty with the double phrase coined by Lord Hoffmann and used by Kitchin J., because it seems to contain a slight ambiguity:
‘If two integers interact upon each other, if there is synergy between them,..’
. The ambiguity is whether the interaction must amount to synergy or whether interaction short of synergy is enough. By contrast, the EPO Guidelines appear not to convey any ambiguity clearly requiring a synergistic effect.[501]The ordinary meaning of synergy is the interaction or cooperation of two or more agents to produce a combined effect greater than the sum of their separate effects i.e. something more than mere interaction. It may not matter overmuch precisely where the dividing line lies between synergy which rules out a collocation and what one might call a mere interaction where a question mark may remain. It is important to keep in mind that the real question is whether there is one invention or more than one, and there will be more than one invention if the relevant parts perform their respective functions independently of each other.[502]However, the dicta cited above indicate that consideration of the interaction between the relevant elements does assist in the determination of one invention or two, provided the right sort of interaction is present. Those dicta also assist in identifying the right sort of interaction.[503]So in Abbott v Evysio, the skilled person, the designer of the stent had to adjust the design of the curved flexure means and the flat apices to produce a satisfactory balance of properties when the stent was in use i.e. during and after deployment. That situation may be contrasted with the situation where the designer has to conduct a trade-off between two elements when designing each, but once the trade-off has been made, thereafter each element performs their function in the patented apparatus independently. This was the situation in SABAF. Mr Tappin KC drew my attention to the judgment of the Court of Appeal in that case because it contains in the Annex, Figure B, one of the drawings from the patent in suit. I reproduce it here because it illustrates the point so well.[504]The air was taken from above the hob surface (this being the first feature) and travelled along the path indicated to mix with the gas in the central lumen 15. The radial Venturi (this being the second feature) occurred in the radial gap marked 22 formed by the undersurface 13’ of the flame spreader 13 and the upper surface 12’ of the body 12.[505]At first instance, Laddie J. held that the two features were a mere collocation and held the patent invalid. Each of the features was disclosed or obvious by separate pieces of prior art (which it was not obvious to combine). On appeal, the Court of Appeal took objection to Laddie J.’s mention of ‘the law of collocation’. The appellant’s argument which found favour with the Court of Appeal centred on the argument that necessarily there was an interaction between the taking of air from above and the radial venturi, but also that the invention was the whole combination of elements in the claim.[506]On further appeal, having referred to the two features, Lord Hoffmann stated in his speech at [16]:
‘There was no item of prior art which taught both. But neither made the other function any differently or produced any combined effect except that each contributed separately to produce a slim hob which was suitable for a work surface over a cupboard.’
[507]On the facts, one possible point of interaction could have been the way in which the body 12 was designed, since it could be said that there was a trade-off in the shaping of the body 12 to produce the radial venturi above and the air path underneath. Although the reports do not indicate any such argument was made, it nonetheless illustrates how a trade off in design would have no effect on the way the two features performed their functions independently in the finished design.[508]Illumina was a somewhat unusual case in which the beneficial properties of the single molecule the subject of claim 1 of the 415 patent derived from the functional relationship, which included non-interference, between the two elements which were the 4 carbon linker form of dye XVI and a derivatised nucleotide plus linker LN3. The skilled team would think that the two elements had the potential to interact in an unwelcome manner, but the Patent showed that they did not. Accordingly, it was not obvious to combine the teaching of the pieces of prior art – Milton and Arnost – which disclosed each of the elements.[509]Fujikura concerned the design of outer sheaths of optical fibre cables which are blown along ducts using a high-pressure stream of air. In that case, the two relevant features were a ribbed outer sheath and ‘IBRs’, intermittently bonded ribbons. The Deputy Judge held that combining those two features did not amount to an obvious collocation. That finding seems inevitable in light of the evidence of the relationship between the two features namely that IBRs were more difficult to blow but imparted more rigidity than non-adhered fibres but less than a traditional ribbon, which affected the air blowing characteristics. The defendant accepted there was a relationship, so far as blowability was concerned, between the choice of IBR for the interior of the cable and the choice of protrusion design for the outer sheath. This explains the Deputy Judge’s use of the expression ‘an interaction between the two features which is relevant to the invention’.

Collocation / Interaction – the Facts

[510]Collocation / Interaction – the Facts As I indicated above, closely linked to the correct construction of the meaning of DMRS in claim 1 is the issue in this case of interaction. ZTE pleaded that claim 1 can be divided into two features and that(i) the Patent does not disclose (plausibly or at all) any interaction between those two features,(ii) no such interaction would be apparent to the skilled person and(iii) there is not in fact any such interaction.[511]The two features were defined and named as follows, and it will be understood that both concern the requirements in claim 1 for the configuration of the processor.[512]The first feature was named “the IFDM / bandwidth feature” and was defined as comprising these elements:
‘receive from a base station a synchronisation signal block, SSB, corresponding to an SSB index (the SSB including a PSS, a SSS, and a PBCH carrying a MIB with a DMRS for demodulating the PBCH), wherein PBCH REs and DMRS REs are interleaved frequency-domain multiplexed and the PBCH and the DMRS for demodulating the PBCH have wider bandwidth than a bandwidth of the PSS or the SSS’
. It can be seen that this feature, as defined, corresponds to Integers 1B and 1C.[513]The second feature was named “the DMRS SSB index feature” and defined as:
‘identify at least full or partial SSB index based on a sequence of the DMRS’
. This corresponds to Integer 1D.[514]I have emphasised the derivation of each of these features because Samsung submitted, by reference to Conor v. Angiotech [2008] UKHL 49; [2008] R.P.C. 8., that the patentee is entitled to have obviousness assessed based on the claim itself, relying on these passages from the speech of Lord Hoffmann at [17] and [19]: [17] … It is the claimed invention which has to involve an inventive step. The invention means prima facie that specified in the claim: see s.125(1) of the 1977 Act. … … [19] … the invention is the product specified in a claim, and the patentee is entitled to have the question of obviousness determined by reference to his claim and not to some vague paraphrase based upon the extent of his disclosure in the description. …[515]On that basis, Samsung emphasised:
‘It is accordingly essential that the formulation of each of the alleged multiple inventions does not descend into “some vague paraphrase” which fails properly to reflect the nature of the features as they sit in the claim as a whole. Put another way, both parts of the claim when divided cannot mean something different to they mean before the division.’
[516]I entirely accept the propositions from Conor and Samsung’s submission. However, as I have endeavoured to demonstrate, the definition of the two features in this case is not some vague paraphrase, they reproduce the wording of the three key integers of the claim. The point does not end there because, as Samsung indicated in the last sentence of that submission, it is important to retain consistency in the construction of terms used in the claim. In this case, the point arises in relation to the DMRS: in short, the DMRS in integer D must be the same DMRS as in integer C and vice versa.[517]Indeed, Samsung’s accusation that ZTE were using a vague paraphrase concerned exactly this point. Samsung submitted that for the IFDM / bandwidth feature, ZTE treated the DMRS as comprising or at least including a pure reference signal, which is all that is required for demodulating the PBCH, if this feature is viewed in isolation. If the sole purpose of the signal is demodulation, the designer wants a pure reference signal which enables direct channel estimation without detection. By contrast, if the DMRS is carrying sequences (e.g. for the SSB index) detection becomes essential, as Mr Anderson pointed out [T3/256/14-257/6]. Dr Wong accepted the same distinction [T2/174/3-175/10]. Furthermore, once detection is necessary, either the preferred coherent detection cannot be performed, or some other signal (with the same bandwidth as the DMRS/PBCH) is going to be required to provide a channel estimate for detecting the DMRS (see Dr Wong XX [T2/181/11-183/4], and Anderson XX [T3/338/23-339/22] and [T3/252/5-19]).[518]As Samsung submitted, throughout the claim, the DMRS must be a synchronisation signal (i.e. carrying multiple hypotheses, and requiring detection), rather than a pure reference signal (carrying a single sequence enabling direct channel estimation without detection) because that is what is required of it to enable it to carry the SSB index as required by Integer 1D.[519]Samsung also submitted that these technical considerations also impact on the relationship of the relative bandwidth between the PSS/SSS and PBCH, and techniques taught in the Patent to enable the PBCH to still be wider bandwidth than the PSS/SSS [T3/248/23-252/19]. If the PBCH has its own DMRS which is a pure reference signal, the DMRS does not require coherent detection and does not need any assistance from the PSS/SSS – enabling an IFDM’d DMRS/PBCH to have any bandwidth greater than the PSS/SSS. However, if the DMRS is to carry multiple sequences, it ideally requires coherent detection for which a channel estimate must come from somewhere, namely the PSS/SSS, so the PSS/SSS either needs to span the same bandwidth, or some other technique (such as non-coherent detection or the special techniques taught in the Patent) is required. See Wong XX [T2/180/11-183/4], and Anderson XX [T3/248/23-252/19].[520]Overall, Samsung submitted that however ZTE ultimately seeks to put its collocation case, there is one coherent overall system. Samsung submitted that this is not a mere ‘sausage machine’ with two parts each individually doing their own thing but merely being joined together as the minced meat travels to the skin-stuffer. Samsung referred to ZTE’s oral opening, in which Counsel sought to deconstruct the embodiment in MFI v. Sabaf to suggest that mere sharing of a feature was not the answer. Samsung’s response was that they do not say that it is. The point of the shared body in MFI is no more than saying that the meat-output tube on the mincer must align with the meat-input tube on the skin-stuffer. That is still mere juxtaposition and hence a collocation. Samsung submitted that is not the sort of interaction which is taking place in Claim 1; the interaction in Claim 1 is equivalent to a situation in which the design at the heart of the mincer has to be reconsidered because of the requirements of skin-stuffer. That is not something which occurs in the familiar example of the sausage machine, or in the House of Lords consideration of MFI’s gas hob.[521]Accordingly, Samsung submitted there was no proper case for a collocation on the basis that there is a lack of ‘interaction’ between the various aspects of the claim.

ZTE’s contentions

[522]ZTE’s contentions For their part, ZTE emphasised how many attempts Samsung had taken to establish an interaction.[523]First, ZTE drew attention to Samsung’s pleaded case (at §3 of Annex 2 to Samsung’s Re-Amended Reply and Defence to Counterclaim and adopted by Mr Anderson in Anderson 1 §§260-262). It was that the skilled person would understand there to be (and there is) an interrelationship between the IFDM / bandwidth feature and the DMRS SSB index feature because the claim requires the DMRS to both demodulate the PBCH and indicate the SSB index. Samsung said that the demodulation requirement favours a DMRS having a single sequence known to the UE (so reducing detection complexity at the UE) whereas the requirement to indicate the SSB index depends on the DMRS having a number of possible sequences (so increasing detection complexity at the UE).[524]That, ZTE contended, does not establish any interaction. Indeed, in that argument, ZTE argued that Samsung were doing exactly what they accused ZTE of doing: giving the DMRS a different meaning in different parts of the claim. As ZTE pointed out, the claim makes a choice (in Integer 1D) in favour of a DMRS with a number of possible sequences, so that the sequence of the DMRS can identify the SS block index, and using such a DMRS to demodulate the PBCH[525]Second, ZTE addressed two other points which Mr Anderson made in his reports (which were not pleaded by Samsung): i) In the first point, Mr Anderson said that reliability of detection is improved by using a small number of sequences in comparison to the sequence length (Anderson 1 §262). ZTE’s response was that was correct, but irrelevant because claim 1 says nothing about the number of hypotheses, the length of the sequences, or the reliability of detection, as Mr Anderson accepted (Anderson T3 257/17–258/6). ZTE emphasised their point that any interaction must be commensurate with the scope of the claim. Nor, they said, does the use of a sequence of any particular length have implications for the bandwidth of the PBCH / DMRS relative to the PSS / SSS – Wong 2 §24. ZTE also pointed out that none of these points were put to Dr Wong in any event. ii) Mr Anderson’s second point (Anderson 1 §263) was that the bandwidth of the information-bearing signal is relevant because, when that is larger than the coherence bandwidth, different parts of the signal are affected differently by the channel and “this has implications for the techniques that are used for its detection, the types of sequences that are employed and the degree of diversity that is afforded.” ZTE responded by saying it was not clear what Mr Anderson was referring to, but none of this can assist Samsung. Claim 1 says nothing about coherence bandwidth. That varies according to the environment of the UE and its velocity relative to the base station and so physical layer signals are designed to work regardless of the coherence bandwidth. There is nothing in the Patent to suggest that any aspect of the IFDM / bandwidth feature needs to take into account coherence bandwidths: see Wong 2 §§25-29, which Samsung did not challenge, nor was any point relating to coherence bandwidth put to Dr Wong. In any event, Mr Anderson did not explain how this has any impact on the DMRS SSB index feature. ZTE remarked in their written closing that they did not consider this point (whatever it was) remained live and this was not contradicted by Samsung.[526]Third, ZTE argued that Samsung put further unpleaded points to Dr Wong in cross-examination.[527]The first unpleaded point was that the bandwidth feature of the claim implied that the DMRS would need to occupy frequency ranges for which the UE was not able to obtain a channel estimate from the PSS or SSS, and that this would prevent the DMRS sequences being detected coherently (Wong [T2 178/9– 183/7]). It was suggested that this gave rise to an interaction because the option to coherently detect the DMRS ‘fell away’ as the bandwidth of the DMRS increased compared to those of the PSS and SSS (Wong [T2 182/23–183/7]).[528]As ZTE submitted, this proceeded from two false assumptions: i) First, it assumed that the bandwidth feature requires that the bandwidth of the DMRS is wider than the bandwidths of both the PSS and the SSS, so that the DMRS cannot take a channel estimate from either. All of Samsung’s counsel’s questions were put on this basis, but claim 1 does not require the PSS and the SSS to have a narrower bandwidth than the PBCH / DMRS. ii) Second, it assumed that the DMRS needs to be coherently detected – indeed the questioning expressly proceeded on that assumption (see T2 179/10-16). However, as indicated already, claim 1 does not require the DMRS to be coherently detected. The skilled person would be aware that in LTE both the PSS and SSS, which used hypotheses of sequences, could be non-coherently detected (see Anderson [T3 237/2-15], Wong [T2 140/24–141/15]).[529]The second unpleaded point which was put to Dr Wong was that the skilled person wanting to implement claim 1 would need to design the IFDM / bandwidth feature and DMRS SSB index feature ‘simultaneously’ so that they could be appropriately specified to work together (Wong [T2 183/8–186/12]).[530]ZTE argued that a hypothetical example of how the skilled person might practically implement claim 1 is very far removed from the question of whether the relevant features interact with each other. Any real product will have to be specified such that its respective features are compatible with each other (e.g. a compact car as postulated by Lord Hoffmann in SABAF at [24]), but that does not mean that the claim is to a single invention. It certainly does not show that the features interact across the scope of the claim, which is completely open-ended as to the number of hypotheses, lengths of sequences and desired performance. In any event, Dr Wong’s evidence was that the system would not necessarily have to be designed as a whole (Wong [T2 184/24–185/14]).[531]Fourth, in the course of his cross-examination, Mr Anderson raised for the first time some embodiments in the Patent which were said to demonstrate an interaction between the IFDM / bandwidth feature and the DMRS SSB index feature: i) The first was the embodiment shown in Figure 21AA. That involves the SSS having the same bandwidth as the PBCH / DMRS, such that the SSS can be used as a reference to demodulate the DMRS, so that it could be detected coherently (Anderson [T3 249/6-14]). ii) The second group was the embodiments in Figures 22-24 of the Patent. Mr Anderson explained that those involve two DMRS sequences, DMRS1 and DMRS2. DMRS1 is cell specific and DMRS2 carries the SS block index information. Once the cell ID is known from the SSS, DMRS1 is known and can be used to coherently detect DMRS2 in the region outside the SSS bandwidth (Anderson [T3 249/16-250/6]). iii) The third group was the embodiments in Figures 21BA (as ZTE submitted, Mr Anderson said AB but his point only makes sense if he meant BA) and BB. In those the DMRS sequence is repeated, such that the instance which overlaps the bandwidth of the SSS can be coherently detected, thereby also providing the instance outside the bandwidth of the SSS (Anderson [T32 50/8-17 & 253/12–254/9]).[532]In response, ZTE made two points: i) First, all those examples are specific embodiments which have, as a common feature, that they allow the DMRS of the claim to be coherently detected. However, as explained above, claim 1 does not require that. ii) Second, the examples are not commensurate with the scope of the bandwidth feature. The Figure 21AA embodiment only allows coherent detection of the DMRS precisely because the SSS has the same bandwidth as the DMRS, yet the claim covers cases in which it has a smaller bandwidth. The Figures 22-24 and 21BA/BB embodiments are specific ones allowing coherent detection even though the SSS has a smaller bandwidth. The claim is much broader than those specific embodiments.[533]For these reasons, ZTE submitted that Mr Anderson’s new examples were therefore irrelevant. ZTE also submitted that it is notable that they emerged when they did, depriving Dr Wong of the ability to comment on them. ZTE submitted there were only two possible reasons for that– either they only occurred to Mr Anderson at a very late stage despite having written two reports addressing interaction or they were considered earlier and rejected. Neither, they said, is consistent with them having any merit.[534]Based on these four points, ZTE argued that the fact that Samsung and Mr Anderson made numerous attempts to find an interaction between the IFDM / bandwidth feature and the DMRS SSB index feature was a good indication that no interaction would be apparent to the skilled person, or in fact exists.[535]ZTE’s fifth and final point was that, following cross-examination, the way Samsung put their case to Dr Wong illustrated its flaws. The XX involved putting to Dr Wong that, if the skilled person were interested in implementing integers B and C of claim 1 (and not constrained by integer D), there would be “no reason” to do anything other than use a single sequence as a reference signal, whereas if they were constrained by integer D “it changes fundamentally the nature of the signal because I now cannot use it to give a direct channel estimate. I have to do detection first” (see T2 173/13–175/12).[536]ZTE submitted the fallacy in this is two-fold. First, even if one did consider integers B and C alone, one is not required to use a single sequence – one can use more than one (Anderson T3 255/12–256/12). Secondly, the claim as a whole requires the use of more than one sequence. But ZTE said that does not mean that there is any interaction between the demodulation requirement and the information-bearing requirement. Indeed, Mr Anderson made it clear that the use of a sequence of the DMRS to indicate the block index would not impact the performance of the DMRS as a reference signal for demodulation of the PBCH once it had been detected (Anderson [T3 261/14–262/13]).[537]ZTE’s further point was that the use of hypotheses does not imply an interaction with the use of IFDM or with a PBCH / DMRS bandwidth which is greater than that of the PSS / SSS (relying once again on Wong 1 §§408-412 & Wong 2 §§19-23). Mr Anderson accepted that what the Patent says about the use of a sequence of the DMRS to indicate the SS block index is independent of the relative bandwidths of the PBCH / DMRS and the PSS / SSS, and of whether TDM or IFDM were used for the DMRS (Anderson [T3 248/11-23]).[538]The issue I must address is whether any interaction between these features is disclosed by the Patent, would be apparent or in fact exists.

Analysis

[539]Analysis I found this a tricky issue, due to the arguments presented. I confess I changed my mind on it whilst preparing this judgment. ZTE’s focus on the number of attempts which they said Samsung made to establish an interaction suggested that Samsung did not appear to have confidence in the earlier attempts. However, I must assess each attempt on its merits. Furthermore, I must also consider whether the other ‘attempts’ were really separate points or just parts of the reasoning given in relation to Samsung’s pleaded response. Certainly, in Mr Nicholson’s reply submissions, his only argument concerned Samsung’s first (pleaded) response.[540]Mr Nicholson focussed first on the role of the DMRS in Integer 1C: for demodulation of the PBCH. He stressed that the reason it is being IFDM’d with it is to ensure that it sits in the same symbol (i.e. time alignment) and covers the same frequency span of the PBCH and it can act as a reference for the PBCH.[541]In Integer 1D, Mr Nicholson stressed you have to remember that the feature – a sequence of the DMRS – must also allow the DMRS to carry out its primary function – to demodulate the PBCH. But that primary function changes in Integer 1D. Now the DMRS must carry sequences to indicate the SS block index, which also means the information to demodulate the PBCH must also be conveyed in a sequence. He characterised this use of the DMRS for two purposes as being unlike the body in MFI, where the top and bottom sides carry out different functions. In this case, the DMRS has to carry out both functions simultaneously.[542]Having considered all these arguments carefully, I have come to the conclusion that there is, in fact, a simple answer to ZTE’s collocation arguments. The answer lies in the fact that the claim is to an overall system in which one cannot consider Integer 1D separately from Integers 1B and C. Indeed, the issue over whether LG 438 disclosed Integer 1C (as properly construed) illustrates this point. If you do take Integer 1C on its own, the first and natural reading would be that the DMRS is a pure reference signal. In the claim as a whole, however, it cannot be a pure reference signal. In short, Integer 1C is undoubtedly affected by Integer 1D.[543]The same point can be put in different ways: i) First, the DMRS has a dual role: it must not only demodulate the PBCH but it must also carry sequences which indicate the SS block index. Thus the normal purpose of the DMRS (simply as a pure reference signal) is changed. These two roles are, in effect, spread across Integers 1C and 1D. ii) Second, claim 1 requires a signal which it happens to call the ‘DMRS’ although it could be called something else. This signal must perform the function of ensuring demodulation of the PBCH, but must also carry sequences to indicate the SS Block Index. Again, these two roles are spread across Integers 1C and 1D.[544]To go in search of synergy is, in this case, not particularly helpful, although combining the two functions into one signal is undoubtedly more efficient than sending two separate signals. Furthermore, the degree of interaction may appear relatively slight but I have concluded it would be wrong to chop claim 1 into two parts on the basis that Integer 1D is a separate invention from the remainder of the claim. It is not. Claim 1 is a claim to an overall system with all the features set out in the claim. Therefore, ZTE’s collocation argument fails.

LACK OF TECHNICAL EFFECT AND PLAUSIBILITY

[545]LACK OF TECHNICAL EFFECT AND PLAUSIBILITY Applicable Legal Principles On this point, the parties took diametrically opposed positions on the relevant approach. One of the key battlegrounds was whether this was ‘a TQ Delta case’ or ‘a Takeda v Roche case’. To explain this, I need to start at the beginning, starting with the way Samsung approached this issue in their Opening Skeleton.

Samsung’s Opening Submissions

[546]Samsung’s Opening Submissions As Floyd LJ observed in Generics v Yeda [2013] EWCA Civ 925; [2014] RPC. 4 at ¶37, neither the EPC nor the Patents Act 1977 provides as a ground of invalidity an objection that the patent does not make a technical contribution to the art.[547]Floyd LJ then considered at ¶¶40-42, the decision of the TBA in AgrEvo T 939/92; [1996] EPOR 171 where there was an issue as to whether it was credible that all compounds within the claim possessed the relevant (herbicidal) activity. The applicant/appellant argued that the possible inclusion within the claims of compounds with no technically useful properties could not form the basis for invalidating the claims for lack of inventive step. The TBA rejected this argument. It stated at [2.4.2] that: … it has for long been a generally accepted legal principle that the extent of the patent monopoly should correspond to and be justified by the technical contribution to the art (see T 409/91, OJ EPO, No. 3.3. and 3.4 of the reasons, and T 435/91, OJ EPO 1995, 188, reasons No.2.2.1 and2.2.2 ). Now, whereas in both the above decisions this general legal principle was applied in relation to the extent of the patent protection that was justified by reference to the requirements of Articles 83 and 84 EPC, the same legal principle also governs the decision that is required to be made under Article 56 EPC, for everything falling within a valid claim has to be inventive. If this is not the case, the claim must be amended so as to exclude obvious subject-matter in order to justify the monopoly. Moreover, in the Board's judgment, it follows from this same legal principle that the answer to the question what a skilled person would have done in the light of the state of the art depends in large measure on the technical result he had set out to achieve. In other words, the notional "person skilled in the art" is not to be assumed to seek to perform a particular act without some concrete technical reason: he must, rather, be assumed to act not out of idle curiosity but with some specific technical purpose in mind.[548]The TBA concluded at [2.5.3] that: It follows from these considerations that a mere arbitrary choice from this host of possible solutions of such a "technical problem" cannot involve an inventive step (see also e.g. T 220/84 of 18 March 1986, No. 7 of the reasons). In other words, the Board holds that, in view of the underlying general legal principle set out in point 2.4.2 above, the selection of such compounds, in order to be patentable, must not be arbitrary but must be justified by a hitherto unknown technical effect which is caused by those structural features which distinguish the claimed compounds from the numerous other compounds.[549]Floyd LJ then summarised the principles to be derived from the authorities at ¶49.(i) Article 56 of the EPC is in part based on the underlying principle that the scope of the patent monopoly must be justified by the patentee's contribution to the art;(ii) If the alleged contribution is a technical effect which is not common to substantially everything covered by a claim, it cannot be used to formulate the question for the purposes of judging obviousness;(iii) In such circumstances the claim must either be restricted to the subject matter which makes good the technical contribution, or a different technical solution common to the whole claim must be found;(iv) A selection from the prior art which is purely arbitrary and cannot be justified by some useful technical property is likely to be held to be obvious because it does not make a real technical advance;(v) A technical effect which is not rendered plausible by the patent specification may not be taken into account in assessing inventive step;(vi) Later evidence may be adduced to support a technical effect made plausible by the specification;(vii) Provided the technical effect is made plausible, no further proof of the existence of the effect is to be demanded of the specification before judging obviousness by reference to the technical effect propounded.[550]These points are especially important in the context of a non-pharmaceutical claim. The starting point in AgrEvo itself is that the EPO considers all claims to chemical compounds to be prima facie obvious (See 2.5.1. citing T 22/82 “a chemical compound was not patentable merely because it potentially enriched chemistry, and that structural originality had no intrinsic value or significance for the assessment of inventive step as long as it did not manifest itself in a valuable property in the widest sense, an effect or an increase in the potency of an effect.”). It is accordingly necessary, in the context of a pharmaceutical compound claim, to establish that there is some non-obvious technical effect which renders that which would otherwise be obvious, patentable. The point of AgrEvo is that this technical effect must be at least plausible over the full scope of the claim. What AgrEvo is not about is imposing a new requirement in every patent case (and, in particular, patent cases in which there is no presumption of obviousness against which the claim needs to be saved) for ‘a promise’ that the patent delivers some ‘technical effect’ in the sense of ‘benefit’ if the underlying claim is already novel and non-obvious.[551]In a similar vein, the following observation of Henry Carr J in TQ Delta v Zyxel [2019] EWHC 562 (Ch) at [156] is also worth noting: There was some debate between the parties as to whether the patented solution has benefits over the Alabama solution. Mr Speck submitted, and I agree, that Agrevo obviousness is not established by suggesting that the prior art provides a solution that might be considered to be as good as that claimed in a patent, by different technical means. Therefore, this debate is, in my view, irrelevant.[552]In the light of those submissions on the legal principles, Samsung then turned to address the allegation made against them in this case.

The allegation in this case

[553]The allegation in this case ZTE asserts that the Patent “does not disclose (plausibly or at all) any technical effect of the DMRS SSB index feature and in so far as it discloses any technical effect of the IFDM / bandwidth feature that technical effect (providing more REs in the frequency domain for information delivery and allowing CSI estimation over the wider bandwidth) is an obvious corollary of the said feature.” It says that, as a result, the Patent “does not plausibly disclose any technical contribution to the art” of claim 1 over the cited prior art (GoI/¶4).[554]Samsung made the following observations about this plea: i) It proceeds on the assumption that ZTE is correct that the claim is a collocation of two independent features and alleges that no technical effect arises from their combination. ii) It appears to be advanced only by reference to the cited prior art – an approach that was rejected as “irrelevant” by Henry Carr J in TQ Delta. iii) It accepts that the patent discloses that the claim does, at least in part, have a technical effect:
“providing more REs in the frequency domain for information delivery and allowing CSI estimation over the wider bandwidth”
. Samsung did not understand how this could be dismissed, apparently as a matter of obviousness. iv) There is no allegation that claim 1 is not capable of industrial application. It is reasonable to infer that ZTE recognises that the Patent is not proposing the transmission and reception of a set of useless signals to no particular end. Rather they are signals that are useful in initial access and mobility. v) Unlike, for example, AgrEvo, it is not a breadth of claim objection where it is suggested that whilst some embodiments of the claim have a technical effect, others do not.[555]Samsung’s case is that claim 1 provides a solution to the problem identified at paragraph [0007] and further described at paragraphs [0087] to [0092] of EP 154.[556]Samsung relied, in particular, on Anderson 1 [228], where Mr Anderson said this: ‘… Use of a wider bandwidth allows for more information to be conveyed via the PBCH or (conversely) for a shorter SS block duration (with fewer PBCH symbols) [footnote: Which may help so support a larger number of blocks or beams (for example, at higher frequencies)]. A wider bandwidth also helps to accommodate the IFDM DMRS without reducing the number of REs that are available for PBCH data (and its FEC protection). …[557]And also [251]: To accommodate beamforming and beam sweeping of SS block transmissions, the patent describes ways in which the indexes of SS blocks or bursts within the burst set may be indicated, including the use of DMRS to do so. In this context, it describes a number of different arrangements of the PSS, SSS, PBCH and DMRS within the time-frequency resource space of an SS block. The examples consider different bandwidths for the PSS, SSS and PBCH (and cases with either one or two PBCH symbols).[558]Accordingly, Samsung submitted that Claim 1 claims particular arrangements of the PSS, SSS, PBCH and DMRS within the time-frequency resource space of an SS block together with a mechanism by which the indexes of SS blocks or bursts within the burst set may be indicated. It thus provides an improved approach to cell search over that in LTE. For example, beamforming is supported, more information can be transmitted on the PBCH, or it can be transmitted over a shorter duration and more beams can be supported, and does so by technical means.[559]Samsung also relied on the fact that claim 1 is accepted to be essential. In view of the fact that ZTE’s plea is not a breadth of claim objection, Samsung submitted that it is for ZTE to explain how it can be said that the claim lacks technical effect despite the fact that it is an essential part of the 5G standard.

ZTE’s Opening Submissions

[560]ZTE’s Opening Submissions ZTE relied on Takeda v Roche [2019] R.P.C. 18 at [203], where Birss J. (as the then was) referred to the principle that the patent monopoly should be justified by the actual technical contribution to the art. He went on to explain at [204]:
“One way in which this principle has been applied in the context of inventive step is to deny validity to a selection from the prior art “which is purely arbitrary and cannot be justified by some useful technical property”
. Such a selection “is likely to be held to be obvious because it does not make a real technical advance”.”[561]At [205], Birss J explained that sometimes the argument is put on the basis that the claim makes no technical contribution over an item of prior art and said that this was a legitimate way of putting the argument. He also explained at [207] that in such a case, for each alleged technical contribution over a prior disclosure:
“there are five questions to answer: Is it disclosed in the patent? Is it plausible? Is it true? Is it a technical advance? Does it support claims of the breadth they are?”
[562]ZTE also relied on Birss J’s further explanation in Optis v Apple [2020] EWHC 2746 (Pat) at [207] (approved on appeal [2021] EWCA Civ 1619 at [58]):
“The principle is not that a claim which contains an arbitrary feature [i.e. a feature which lacks technical effect] is invalid. Merely having an arbitrary feature in a claim is not a ground of invalidity. The point of AgrEvo obviousness is that if a claim is found to contain an arbitrary limitation in it, then that limitation cannot assist the patentee in defending an obviousness case. The claim still does have to be obvious over something in the state of the art – perhaps common general knowledge or some cited prior art.”
[563]Samsung acknowledged these points and accepted in closing that, it was, in principle, open to ZTE to get as far as it was able with its obviousness case (whether classic on LG 434, or in the context of its collocation) and then contend that such feature or features that remain are merely arbitrary and cannot save the Patent.[564]For their part, Samsung argued this is a TQ Delta case and that Takeda v Roche is not applicable.[565]In relation to Takeda v Roche, Samsung accepted the principle set out by Birss J. which I have quoted in [560] and [561] above but they pointed out that the principle was stated in the context of chemical selection patents, where a super-set of the claimed compounds are disclosed by the prior art. In such a case, it is legitimate to claim a sub-set in a new patent, provided that some technical contribution over and above that which is already known is plausibly disclosed. Samsung therefore characterised the Takeda questions as providing a structure to address that type of situation.[566]By contrast, Samsung submitted this is not a Takeda case at all. The Patent is not seeking to claim a subset of something which is already known. Therefore, there is no need for the Patent to validate the claim by justifying some ‘technical contribution’ relative to the state of the art.[567]Samsung argued that the Patent claims a technical solution which is different from, and not rendered obvious by, the prior art, and that is all that is required. Therefore, per Henry Carr J in TQ Delta, Samsung said ZTE’s arguments were irrelevant.[568]In his oral closing, Mr Tappin took me through Takeda v Roche in some detail.[569]To understand the case, it is necessary to start with claim 1 which was under attack, quoted at [3]. “Monoclonal antibody of human IgG1 or IgG3 type being glycosylated with a sugar chain at Asn297, said antibody being characterized in that the amount of fucose within said sugar chain, related to the sum of G0, G1, G2 without mannose 4 and mannose 5 as 100% and as analyzed by Liquid Chromatography/Mass Spectrometry (LCMS) peptide map analysis is at least 99% and in addition the amount of NGNA within said sugar chain, related to the sum of G0, G1, G2 without mannose 4 and mannose 5 as 100% and as analyzed by Liquid Chromatography/Mass Spectrometry (LCMS) peptide map analysis, is 1% or less, and the amount of N-terminal alpha 1,3 galactose within said sugar chain related to the sum of G0, G1, G2 without mannose 4 and mannose 5 as 100% and as analyzed by Liquid Chromatography/Mass Spectrometry (LCMS) peptide map analysis is 1% or less.”[570]It is convenient to identify Takeda’s argument and Roche’s response by citing these paragraphs (my emphasis): ‘205 Sometimes the argument in this case is put on the basis that the claim makes no technical contribution over an item of prior art. The two candidates are Shields, which was common general knowledge and Bihoreau. Not every case looks at this issue in that way but it is a legitimate way of putting the argument. 206 Roche was dismissive of this issue in closing, identifying three contributions to the art which, it argued, the patent obviously made. The contributions were made by:(i) disclosing that CHO cells can be obtained having fucosylation of >99%;(ii) disclosing the idea of increasing fucose for a therapeutically useful purpose;(iii) disclosing the idea that increasing fucose to 99%. would reduce ADCC to background.[571]Birss J. rejected the first alleged contribution on several grounds. Although the idea was plausible and true, but he held it was not a technical advance contributed by the patent because the prior art included disclosures of antibodies with fucosylation of >99%. Birss J. also held that, in any event, it was an arbitrary level of fucosylation. Furthermore, there was a mismatch between this alleged contribution – limited to CHO cells – and the claim, which was not limited to products made in CHO cells, and because fucosylation was well known to depend on cell type.[572]As to the second alleged contribution, the idea was disclosed in the patent, it was plausible and true. Increasing fucose reduces ADCC and reducing ADCC is a therapeutically useful thing to do for certain antibodies. However, Birss J. rejected that it was a technical advance, because the idea that reducing ADCC was a therapeutically useful thing to do for certain antibodies was part of the common general knowledge and so too was the idea that increasing fucose would reduce ADCC. So Birss J. concluded ‘This is not an advance over what was known.’[573]On the third, Birss J. identified that the patent never actually said what was alleged to have been disclosed. It is unnecessary to go into the detail, but the evidence did not satisfy him that the skilled person would identify this idea from the teaching in the patent. Furthermore, Birss J. was not convinced the idea was plausible, nor that the proposition was true but he said it would have been a technical advance.[574]Having taken me through the reasoning, Mr Tappin returned to ZTE’s arguments on the facts, as presented succinctly in their closing skeleton argument as follows:
‘103. The questions to be asked in respect of each alleged technical contribution over the prior art are those set out in Takeda v Roche at [207], quoted in §90 of our opening skeleton. As we said in our oral opening: (1) as regards the DMRS SSB index feature, there is no technical effect disclosed plausibly or at all in the Patent (and of course the idea is disclosed in LG 434); (2) as regards the IFDM feature, the only technical effect disclosed in the Patent is allowing channel estimation over the bandwidth of the channel the signal is to demodulate, and that is not a technical advance because it was part of the CGK; (3) as regards the bandwidth feature, the only technical effect disclosed in the Patent is providing more REs in the frequency domain for information delivery. That was not a technical advance because it was part of the CGK and in any event it is not commensurate with the claims because there is no correspondence between the claims and having more REs in the frequency domain for information delivery, because bandwidth of the PBCH is not defined in absolute terms but relative to the bandwidths of the PSS / SSS.’
[575]In his oral submissions, Mr Tappin made the following additional points: i) First, there had been no suggestion from Samsung that it was incorrect to take each of these three contributions separately. Although it may not have appeared at the forefront of Samsung’s arguments, I consider that Samsung made exactly this point. ii) Second, that to the extent that Samsung identified any technical effects in their closing submissions, these were not set out in the Patent. I think this argument misses the point. Not every technical effect must be spelled out in the Patent if the technical effect would be readily apparent to the Skilled Reader.[576]Having made those points he then reverted to the way the arguments had been set out in ZTE’s closing skeleton argument, which I have covered above.

Analysis

[577]Analysis In relation to the relevant part of Takeda v Roche, I think it is important to note that the issue was whether the claim made a technical contribution. The alleged contributions considered by Birss J in that case related to the effect of claim 1 as a whole as I understand matters. It was not a case where individual integers in the claim were assessed for their individual technical contribution.[578]This, of course, makes sense. It cannot be right to chop a claim up into pieces and argue that piece 1 makes no technical contribution because that feature can be found in the prior art and that piece 2 is to be found in the CGK and so on, thereby never addressing the claim as a whole (in the absence, of course, of a successful collocation argument).[579]So, in my view, there is a relatively simple answer to ZTE’s allegation of no technical contribution: ZTE’s argument does not address the claim as a whole. When one considers the claim as a whole, it is accepted to be essential to the 5G standard. In those circumstances, it is very difficult to see (as Mr Nicholson submitted) how this claim can lack having made a technical contribution to the art.[580]I should add that I did not find Samsung’s reliance on TQ Delta to be helpful, although I accept I have reached the same end result: ZTE’s arguments are irrelevant.[581]Accordingly, I reject ZTE’s argument that claim 1 of the Patent makes no technical contribution.

OVERALL CONCLUSIONS

[582]OVERALL CONCLUSIONS In the light of my reasoning above, I find: i) The Patent does not lack an inventive step over LG 434. ii) ZTE’s collocation argument fails. iii) ZTE’s argument of lack of technical contribution fails.[583]That the Patent is essential to the 5G standard was agreed. Accordingly, I will declare that the Patent is valid, essential and has been infringed by ZTE. In the absence of a FRAND licence, ZTE threatens to continue to infringe.[584]Although I have taken a long time to complete this Judgment, I encourage the parties to arrange the form of order hearing in early course. 586. Annex - List of Abbreviations Term Definition ACTS Advanced Communications Technologies and Services ASN.1 Abstract Syntax Notation BCCH Broadcast Control Channel BCH Broadcast Channel BPSK Binary Phase Shift Keying BS Base Station CDFs Cumulative Distribution Functions CDM Code Division Multiplexed CDMA Code Division Multiple Access CFO Carrier Frequency Offset CGK Common General Knowledge CN Core Network CoMP Co-Ordinated Multi Point CP Cyclic Prefix CRC Cyclic Redundancy Check C-RNTI Cell Radio Network Temporary Identifier CRS Cell-specific Reference Signal CSI-RS Channel-State Information Reference Signal D2D Device-to-Device communications DAC Digital-to-Analogue Converter DCI Downlink Control Information DFT-S-OFDM Discrete Fourier Transform Spread Orthogonal Frequency Division Multiplexing DL-SCH Downlink Shared Channel DMRS Demodulation Reference Signal DSP Digital Signalling Processing eMBB enhanced Mobile Broadband eNB eNodeB EP European Patent EPC Evolved Packet Core ESS Extended Synchronisation Signal ETSI European Telecommunications Standards Institute E-UTRAN Evolved Universal Terrestrial Radio Access Network FD-MIMO Full Dimensional MIMO FDD Frequency Division Duplex FDMA Frequency Division Multiple Access FFS For Further Study FFT Fast Fourier Transform FSTD Frequency Switched Transmit Diversity gNB gNodeB GSM Global System for Mobile communication HSDPA High-Speed Downlink Packet Access IF Intermediate Frequency IFDM Interleaved Frequency Division Multiplexing IoT Internet of Things ITU-R International Telecommunications Union (Radiocommunication sector) LDPC Low Density Parity Check LSBs Least Significant Bits LTE Long Term Evolution M2M Machine to Machine MAC Medium Access Control MBSFN Multicast Broadcast Single Frequency Network MCC Mobile Competence Centre MIB Master Information Block MIMO Multiple Input Multiple Output MMSE Minimum Mean Squared Error mMTC Massive Machine Type Communications MSBs Most Significant Bits MTC Machine Type Communications NR New Radio OFDM Orthogonal Frequency Division Multiplexing OFDMA Orthogonal Frequency Division Multiple Access PBCH Physical Broadcast Channel PCFICH Physical Control Format Indicator Channel PDCCH Physical Downlink Control Channel PDSCH Physical Downlink Shared Channel PHICH Physical Hybrid ARQ Indicator Channel PSK Phase Shift Keying PSS Primary Synchronisation Signal PUSCH Physical Uplink Shared Channel PUCCH Physical Uplink Control Channel QAM Quadrature Amplitude Modulation QoS Quality of Service QPSK Quadrature Phase Shift Keying RAN Radio Access Network RAR Random Access Response RAT Radio Access Technology RB Resource Block RE Resource Element RF Radio Frequency RR Radio Resources RRC Radio Resource Control RRM Radio Resource Management RS Reference Signals RSRP Reference Signal Received Power RSRQ Reference Signal Received Quality SC-FDMA Single Carrier Frequency Division Multiple Access SCS Subcarrier Spacing SFBC Space-Frequency Block Coding SFN System Frame Number SI System Information SIB System Information Block SI-RNTI System Information Radio Network Temporary Identifier SRS Sounding Reference Signal SS Synchronisation Signal SSB Synchronisation Signal Block SSS Secondary Synchronisation Signal TDD Time Division Duplex TDM Time Division Multiplexed / Time Domain Multiplexed TDMA Time Division Multiple Access TRP Transmit Receive Point TR Technical Report TS Technical Specification TSS Tertiary Sync Signal TSG Technical Specification Group TTI Transmission Time Interval UCI Uplink Control Information UMTS Universal Mobile Telecommunications System URLLC Ultra Reliable Low Latency Communications WF Way Forward WG Working Group ZC Zadoff-Chu 3GPP Third Generation Partnership Project