Conversant Wireless Licensing SARL v Huawei Technologies Co., Ltd & Ors

A patent claim must be construed purposively in light of the specification. A virtual transmission time interval may define permitted cyclic starting points for transmissions rather than a fixed gap between them, and a claim is not confined to a particular MAC layer or service unless its language requires that limitation.

For added matter, the relevant comparison is between the disclosure of the application as filed and the patent, viewed through the eyes of the skilled person. The question is whether the amendment discloses new information, not merely whether it gives the claim broader coverage. A claim may be essential to a standard and infringed, yet invalid for added matter.

Conversant was proprietor of European Patent (UK) No 1 797 659 concerning uplink transmission in HSUPA. It alleged that the patent was essential to Uplink DRX in UMTS and had been infringed by Huawei and ZTE. The defendants counterclaimed for revocation on added matter, obviousness and insufficiency. Conversant sought unconditional amendment of the claims.

The central issues were the construction of claim 1, whether Uplink DRX fell within its scope, whether the claims disclosed added matter, and whether the claims were obvious over Samsung or Terry or insufficient.

1. Construction. Claim 1 was not limited to selectively restricting autonomous transmissions, leaving scheduled transmissions unaffected. Nor was it confined to implementation in MAC-d or to a service-specific solution. The expression “virtual transmission time interval” defined cyclic permitted starting points for transmissions, not a fixed gap between the end of one transmission and the start of the next. “Data packets” was not limited to VoIP packets. The checking requirement concerned whether the MAC was transmitting at the end of the current TTI, assessed by whether it could empty the RLC buffer.
2. Essentiality and infringement. Uplink DRX satisfied the integers of claim 1 where the MAC Inactivity Threshold was 1. The MAC DTX cycle supplied the virtual transmission interval, and the buffer-occupancy check supplied the relevant transmission determination. Although the check was made by reference to the previous TTI, this was an equivalent under Actavis UK Ltd v Eli Lilly & Co [2017] UKSC 48, [2017] RPC 21. The patent was therefore essential to Uplink DRX and claim 1 was infringed if valid.
3. Added matter. The application as filed disclosed checking whether the MAC could empty the RLC buffer during the current TTI, followed by waiting or transmitting. It did not disclose the distinct check of whether the MAC was transmitting in the current TTI. That amendment disclosed new information. Claim 1 was consequently invalid for added matter, and the proposed amendment did not cure the defect. The other added-matter allegations failed.
4. Obviousness and insufficiency. The claims were not obvious over Samsung or Terry. Samsung did not disclose continued transmissions where the buffer could not be emptied, and Terry could not be discarded and then replaced by common general knowledge to produce the claimed invention. No coherent insufficiency case succeeded.