Optis Cellular Technology LLC v Apple Retail U.K. Ltd
| Jurisdiction | England & Wales |
| Judge | Lord Justice Arnold,Lord Justice Nugee,Lord Justice Birss |
| Judgment Date | 25 April 2023 |
| Neutral Citation | [2023] EWCA Civ 438 |
| Docket Number | Case No: CA-2022-000108 |
| Court | Court of Appeal (Civil Division) |
[2023] EWCA Civ 438
Lord Justice Arnold
Lord Justice Nugee
and
Lord Justice Birss
Case No: CA-2022-000108
IN THE COURT OF APPEAL (CIVIL DIVISION)
ON APPEAL FROM THE HIGH COURT OF JUSTICE, BUSINESS AND PROPERTY
COURTS OF ENGLAND AND WALES, INTELLECTUAL PROPERTY LIST (ChD),
PATENTS COURT
Mr Justice Meade
Royal Courts of Justice
Strand, London, WC2A 2LL
James Abrahams KC, James Whyte and Michael Conway (instructed by EIP Europe LLP) for the Appellants
Lindsay Lane KC and Adam Gamsa (instructed by Wilmer Cutler Pickering Hale and Dorr LLP) for the Respondents
Hearing dates: 14–15 March 2023
Approved Judgment
Introduction
This is an appeal by the Claimants (“Optis”) from an order of Meade J dated 10 December 2021 revoking European Patents (UK) Nos. 2 093 953, 2 464 065 and 2 592 779 for the reasons given in the judge's judgment dated 25 November 2021 [2021] EWHC 3121 (Pat). The judge's decision was made following the third technical trial (Trial C) between Optis and the Defendants (“Apple”) in their dispute over the terms of a FRAND licence of Optis' portfolio of allegedly standard-essential patents.
The patents in suit are all closely related and from the same family. It was and remains common ground that it is only necessary to consider claims 1 and 4 of European Patent (UK) No. 2 093 953 (“the Patent”). There is no challenge to the claimed priority date of 19 February 2008. Apple accepted that the Patent is essential to the LTE 4G mobile telecommunications standard, and therefore infringed if valid. The judge held that claims 1 and 4 of the Patent were both obvious over Slides R1-081101 entitled “PDCCH Blind Decoding — Outcome of offline discussions” presented at a meeting of RAN1 (Radio Access Network Working Group 1) on 11–15 February 2008 (“Ericsson”), although he rejected certain other attacks on the validity of the Patent. Optis appeal with permission granted by myself.
The skilled person
The judge found at [28]–[40] that the person skilled in the art to whom the Patent was addressed was a person engaged in work on RAN1.
The expert witnesses
Optis' expert witness was Johanna Dwyer. Apple's expert witness was Professor Angel Lozano. The judge found at [11]–[17] that Ms Dwyer was a good witness, but that the subject-matter of the Patent was “materially outside her area of expertise”. As a result, her evidence was “of extremely limited help on the key issues in this case”. By contrast, the judge found at [18]–[27] that Prof Lozano had relevant experience, had “a practical approach” and was “an excellent witness” who was “much more cogent … than Ms Dwyer”. In general, therefore, the judge preferred Prof Lozano's evidence to that of Ms Dwyer, but warned himself that he should not accept anything Prof Lozano said uncritically.
It is worth considering why the judge was right to give himself that warning. It is because of the function of expert witnesses in patent cases. Experts usually have little or no expertise in the issues which confront the court, such as the obviousness of a claimed invention to a person skilled in the art. Thus the experts' primary function is to educate the court in the relevant technology. This was explained by Jacob LJ in a number of judgments. It is sufficient for present purposes to cite what he said in SmithKline Beecham plc v Apotex Europe Ltd [2004] EWCA Civ 1568, [2005] FSR 23:
“52. … although it is inevitable that when an expert is asked what he would understand from a prior document's teaching he will give an answer as an individual, that answer is not as such all that helpful. What matters is what the notional skilled man would understand from the document. So it is not so much the expert's personal view but his reasons for that view—these the court can examine against the standard of the notional unimaginative skilled man. …
53. Thus in weighing the views of rival experts as to what is taught or what is obvious from what is taught, a judge should be careful to distinguish his views on the experts as to whether they are good witnesses or good teachers—good at answering the questions asked and not others, not argumentative and so on, from the more fundamental reasons for their opinions. Ultimately it is the latter which matter—are they reasons which would be perceived by the skilled man?”
Agreed common general knowledge
The judge set out the agreed common general knowledge at [47]–[104]. This included a topic which Optis did not agree was common general knowledge, but accepted would be apparent from Ericsson, namely collisions and blocking. I shall largely take that necessarily detailed exposition as read, and briefly summarise the points that matter for present purposes; but when it comes to collisions and blocking it is necessary to reproduce the judge's explanation in full.
PDCCH in LTE
In LTE what defines a channel depends on the level in the protocol stack. Between the Radio Link Control (RLC) and the Medium Access and Control (MAC) sublayers, “logical channels” are used to carry information for certain purposes. At the MAC sub-layer, two or more logical channels may then be combined into a single “transport channel”, for onward transmission to the physical layer. At the physical layer, transport channels are mapped to “physical channels”, which are configured to have a particular structure and to use a particular set of resources.
LTE has some physical control channels which carry signaling necessary to configure transmissions on the physical layer, such as resource allocations. In the downlink, these include the Physical Downlink Control Channel (PDCCH). Depending on context, PDCCH may refer to a specific single control channel between the eNodeB (base station) and an individual UE (user equipment) or to all such channels.
In LTE radio resources are divided up according to a two-dimensional space in the time and frequency domains. In the time domain LTE uses units of 10 ms called a radio frame, each of which is further divided into ten 1 ms subframes.
The PDCCH carries Downlink Control Information (DCI), which contains critical information for the UE, because it informs the UE about its uplink resource allocation and where to find its information on the downlink. The DCI is sent in PDCCHs in the control region at the start of the downlink subframe. The design of the PDCCH includes the UE procedure for determining its PDCCH assignment. Aspects of the PDCCH assignment procedure and how UEs would monitor the control region to find PDCCH for them to obtain DCI were still in development at the priority date.
The PDCCH is organised into control channel elements (CCEs). A PDCCH message is transmitted on either 1, 2, 4 or 8 CCEs, called “CCE aggregations”. A CCE aggregation that may carry a PDCCH message for a UE is referred to as a “PDCCH candidate”.
Each subframe, a UE has to monitor the PDCCH to determine whether it contains DCI messages intended for it. To detect whether a PDCCH candidate contains control information for the UE, the UE searches for its unique identifier (referred to as the “UE ID”). The UE ID is allocated temporarily to the UE by the eNodeB when the UE enters that cell. The UE ID is encoded in the Cyclic Redundancy Check (CRC) of the PDCCH for that UE. The CRC is scrambled or “masked”. The process of searching for the UE ID in the masked CRC of the PDCCH is referred to as “blind decoding”.
Because it would be resource intensive to require each UE to monitor and attempt to blind decode the whole of the PDCCH each subframe, a UE is only required to monitor a subset of all possible PDCCH candidates, called a “search space”. A search space can be defined by its starting point and size; and if the size is fixed, by just the starting point.
Collisions and blocking
In the specific context of search spaces on the PDCCH, a “collision” refers to the search spaces completely overlapping (i.e. starting at the same location). To illustrate this concept, the diagram below shows one way that the search space for six UEs might be arranged. The search space for each UE is shown in a different colour. In the diagram, the size of the search spaces at each aggregation level is 6 aggregations at each of aggregation levels 1 and 2 (the top two levels in each case, with 32 CCEs and 16 CCEs), and 2 aggregations at each of levels 4 and 8 (the bottom two levels in each case, with 8 and 4 CCEs).
Illustrative example of search spaces and actual allocation for 6 UEs
In each subframe, the eNodeB chooses where within each UE's search space to allocate DCI messages for that UE. One possible such choice is shown in the “eNodeB allocation” section of the diagram above. In this example, the eNodeB is sending one message for each UE. The eNodeB has chosen the aggregation level for each UE, and identified an arrangement for all the messages so that each UE's message is within that UE's search space at the appropriate aggregation level. This process is repeated in the next subframe.
There may be circumstances in which the eNodeB is not able to find locations for all the messages it wishes to send. For example, in the diagram above, the eNodeB could not send a DCI message at aggregation level 8 to all of UEs 1, 2 and 5. The search space at aggregation level 8 for these three UEs completely overlaps, and comprises only two CCE aggregations. This is an example of “blocking”. One of the three UEs is blocked; the eNodeB has to make a decision as to which UE's message it will not send in that subframe.
In other circumstances, search spaces...
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Optis Cellular Technology LLC and Ors v Apple Retail UK Ltd and Others
...for it but has to decode candidate CCEs until it finds one addressed to it. One of the previous Optis v Apple appeals this year ( [2023] EWCA Civ 438) was concerned with a way of limiting the number of CCEs which the mobile had to decode in order to find the right one. Once a mobile has de......