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Conversant v Huawei: The Doctrine of Equivalents in the Telecoms Sector

By Brian Whitehead, Consultant and Greg Ward, Partner

The impact of the landmark Supreme Court decision in Eli Lilly v Actavis (relating to the doctrine of equivalents) has now reached the telecommunications sector with the issuance earlier this month of the High Court decision in Conversant v Huawei. The patent in question, EP (UK) 1797659, is entitled “Slow MAC-e for autonomous transmission in high speed uplink packet access (HSUPA) along with service specific transmission time control”, and relates to access control systems for wireless telecommunication networks.

Conversant contended that EP (UK) 1797659 is essential to an aspect of the third generation mobile phone Universal Mobile Telecommunications Standard (“UMTS”) referred to as “Uplink DRX”. Discontinuous reception (DRX) allows device power consumption to be reduced by deactivating portions of a device when not required for transmission; this is of particular use for user devices (such as mobile phones) that rely on battery power. In this context, the “uplink” transmissions are from a user device to a base station; transmissions from a base station to a user device would be referred to as “downlink” transmissions. Although the patent forms part of a group of Conversant patents subject to a FRAND undertaking, no license had been agreed between Conversant and the defendants at the time of the hearing.

By way of recap, in Actavis the Supreme Court ruled that a patent can be infringed by a variant which falls outside the scope of a patent claim on a literal or purposive construction, and provided the following three-step test to determine infringement:

  1. Notwithstanding that it is not within the literal meaning of the relevant claim(s) of the patent, does the variant achieve substantially the same result in substantially the same way as the invention, i.e. the inventive concept revealed by the patent?
  2. Would it be obvious to the person skilled in the art, reading the patent at the priority date, but knowing that the variant achieves substantially the same result as the invention, that it does so in substantially the same way as the invention?
  3. Would such a reader of the patent have concluded that the patentee nonetheless intended that strict compliance with the literal meaning of the relevant claim(s) of the patent was an essential requirement of the invention?

In order to establish infringement in a case where there is no literal infringement, a patentee would have to establish that the answer to the first two questions was “yes” and that the answer to the third question was “no”.

As is customary, the judge (Arnold J) broke claim 1 of the patent down into its integers. Integer C, which gave rise to the infringement by equivalents issue, reads:
“checking to determine whether the medium access control entity is transmitting data packets in a current air interface transmission time interval, by checking whether the medium access control entity is able to empty the radio link control buffer in the current air interface transmission time interval”.

The Defendants contended that Uplink DRX does not comply with the requirement of integer C, because the check in question is carried out with respect to the previous transmission time interval (“TTI”), rather than the current TTI as specified in integer C. Conversant agreed with that, but contended that Uplink DRX nevertheless infringes, as it achieves substantially the same result in substantially the same way as the invention, that this would be obvious to the skilled person and that the skilled person would not think that strict compliance was required; the three-step test from Eli Lilly v Actavis would therefore be satisfied.

It is usual practice, in patent litigation in which infringement by equivalents is contended, specifically to plead the argument and then to advance evidence in support. It is not, therefore, simply a matter for Counsel’s submissions – expert evidence is generally key to establishing infringement by variants, particularly in relation to questions 2 and 3 of the Actavis questions. Conversant appears to have pleaded infringement by variants – certainly, its expert addressed each of the Actavis questions in his report. For reasons which are not clear from the judgment, however, the Defendants did not cross-examine Conversant’s expert in relation to this aspect of the claim, nor did they deal with equivalence in written closing submissions. It appears that the issue was addressed only in supplemental written closing submissions made in response to a direct question from the judge.

Perhaps inevitably, in view of the lack of challenge to Conversant’s evidence, the judge concluded that “The Defendants have no coherent answer to Conversant’s case that Uplink DRX is equivalent to integer C …”. As a result of that and his other conclusions, the judge held that the patent is essential to Uplink DRX in UMTS. He did, though, go on to conclude that the patent is invalid for added matter, and consequently the finding of infringement by equivalents is of academic interest only to the parties.

It is regrettable that on this first outing of the Actavis questions in the telecommunications patents sector (which is, by volume of cases, one of the two key sectors, alongside pharmaceuticals), the issue was not fully explored and argued, and the argument appears to have succeeded almost by default. A full consideration of the implications of Actavis for the telecommunications sector, therefore, will have to wait for another day.