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UK – Interdigital Technology v. Lenovo

14 Aug 2021

Interdigital Technology Corp and others v Lenovo Group Ltd and others [2021] EWHC 2152 (Pat)

This judgment, handed down on 29 July 2021, concerned the validity and essentiality of EP (UK) 2 485 558 (“EP 558”). HHJ Hacon’s judgment is the first technical trial in a series of trials concerning five SEPs asserted by the claimants (“InterDigital”) against the defendants (“Lenovo”) in the field of 3G and 4G telecommunications technology.

The parties had been in discussions regarding the licensing of EP 558 (as part of InterDigital’s wider portfolio) since 2009. InterDigital claimed that since June 2010 it had made a number of offers to Lenovo to license its patent portfolio on FRAND terms. However, negotiations between the parties had broken down. InterDigital alleged that Lenovo infringed EP 558 by importing 4G devices into the UK. In addition, InterDigital alleged that Lenovo was not a willing FRAND licensee, or alternatively would not commit to accepting the burden of the FRAND licence offered and that accordingly Lenovo cannot enforce InterDigital’s FRAND obligations.

The invention contained in EP 558 allows mobile phone users quick and efficient access to 4G (LTE) networks.

The judge was asked to decide at what date a patent specification should be construed: the priority date or the date of the filing of the application (neither of which interestingly reflect what is implied in Terrell which is that it may be the date of publication). The point arose in relation to a construction issue regarding what the skilled person would have considered to be a base station (referred to in LTE as an “eNB”) at the relevant date. The skilled person’s understanding of an eNB would have evolved between the priority date of the EP 558 in January 2006 and the finalisation of Release 8 of LTE in December 2008.

While the judge acknowledged that in Biogen v Medeva [1997] RPC 1, Lord Hoffman had ruled that sufficiency was to be assessed at the date of filing of the patent application, HHJ Hacon held that Lord Hoffman’s ruling had to be read in light of the Supreme Court’s judgment in Regeneron v Kymab [2020] UKSC 7 which he interpreted as meaning that sufficiency is to be assessed as of the priority date if valid, or if not, the filing date. Indeed, Biogen had been a case in which there was no valid priority date.

Lenovo cited two items of prior art: (i) a patent application (“Laroia”); and (ii) a T-doc (“Samsung”). While Laroia was relied on for both anticipation and obviousness, Samsung was pleaded in respect of obviousness only.

Samsung is a T-doc (a technical document submitted for discussion at 3GPP working group meetings during the development of LTE) titled “LTE State & State transitions”. Samsung contemplates two possible methods by which user equipment (e.g. a handset) could ask for additional uplink resources. The issue as to whether EP 558 was obvious over Samsung turned on whether it was obvious to implement one of the options in Samsung in a particular manner (i.e. to reduce the size of the 18-bit message proposed by Samsung to a 1-bit message which solely by its presence indicated a scheduling request). The judge found that, although sending a 1-bit transmission burst was known at the time, the skilled person would not have focused on this aspect of the required option in Samsung and instead the skilled person’s mind would have stayed with what Samsung was recommending. Therefore, all claims of EP 558 were found to be inventive over Samsung.

Laroia is a patent application for an invention to permit a relatively large number of user devices to be supported by a single base station.

In assessing the novelty of claims 1 and 14 of EP 558 over Laroia, HHJ Hacon found that a number of the integers in dispute were not clearly and unambiguously disclosed by Laroia and hence these claims were not anticipated.

Regarding the obviousness of claims 1 and 14 in light of Laroia, the judge found InterDigital’s expert witness evidence persuasive as to why it would not have been obvious to the skilled person to make changes to Laroia such that the state transition request was doubled-up so that it was also a scheduling request. The judge found that it was unlikely that the skilled person would have been thinking about Laroia in the sense of adapting it for use in a network using an eNB.

HHJ Hacon went on to consider whether claims 9 and 19 (as granted and as proposed to be amended) were independently valid over Laroia. On the basis that Lenovo’s expert witness was more convincing on the issue (whether the Laroia user equipment in a particular state would use a particular channel for HARQ signalling), the judge held that claims 9 and 19 were not independently valid over Laroia either as granted, or in their proposed amended form (since the proposed addition made no difference to inventive step).

InterDigital had also suggested claims 13 and 22 (which related to combining code multiplexing with frequency and time multiplexing) were independently valid. However, InterDigital’s expert witness conceded that the skilled person reading Laroia may have seen some benefit in also using code multiplexing and may have experimented. Therefore, claims 13 and 22 of EP 558 were held not to be independently valid over Laroia.

Lenovo had raised two arguments on insufficiency. First, Lenovo alleged that it was not possible to build an eNB at the priority date. However, this attack failed as HHJ Hacon had already held that an eNB of claim 1 is properly construed as particular type of eNB which it was possible for the skilled person to make at the priority date.

Second, Lenovo argued that the specification did not enable the skilled person to use a 1-bit transmission burst, the presence of which is indicative of a scheduling request, for the concurrent purpose of signalling an ACK/NACK. HHJ Hacon applied Regeneron and held that it was enough that the skilled person could perform the invention by using the teaching disclosed in the patent coupled with the common general knowledge available at the priority date and so the patent was held to be sufficient.

Conditional Amendments
Since the patent was found to be valid as granted, InterDigital’s application to amend did not need to proceed. Both Lenovo and HHJ Hacon in his judgment declared themselves “baffled” as to why the court’s time was taken up by the application. However, since it was argued, HHJ Hacon did deal with it.

Lenovo had opposed the proposed amendment to claim 9 on the basis that it resulted in an internal inconsistency which amounted to a lack of clarity as to whether the invention could only be implemented across a limited sub-set of its apparent scope. The judge held that the skilled person would have no difficulty in implementing the invention using their common general knowledge and there was no reason to suppose that the claim was more limited in scope that the clear words suggested. Therefore, the objection on lack of clarity would have failed.

Lenovo also opposed the proposed amendments to claims 9 and 19 on the ground that they would constitute intermediate generalisations. HHJ Hacon agreed and held that a feature had been taken from the specification and introduced into the proposed amended claims in circumstances where it would not be apparent to the skilled person that it had any general applicability to the invention. Therefore, the proposed amended claims provided the skilled person with new information about the invention which would not have been directly and unambiguously apparent from the original disclosure.

Lenovo argued that the patent was not essential to Release 8 of LTE. The issue turned on whether a specific claim integer of claim 1 was required by the standard i.e. whether in an LTE network, the configuration allocated by the eNB indicates which sub-carrier resource of the NCB uplink control channel was to be used by the UE for transmitting the scheduling requests. In finding the patent to be essential, HHJ Hacon noted that InterDigital could have used words such as “governs” or “determines” but chose not to. Accordingly, the method of the LTE system fell within claim 1 of the patent.

EP 558 was therefore held to be valid, essential to Release 8 of LTE and, since Lenovo uses LTE, infringed. As such, InterDigital’s conditional application to amend EP 558 fell away. The next trial scheduled for 2022 is a FRAND trial.

A copy of the judgment can be found here.

Headnote by Sam Harvey, Bristows LLP