Interdigital Technology Corporation & Ors v Lenovo Group Limited & Ors

A patent claim should be construed purposively and in context. Where prior art is expressly acknowledged, forms part of common general knowledge and is the source of the problem addressed, a construction which claims that prior art may produce a foolish result and should generally be rejected. In assessing obviousness, the identification of a technical problem may contribute to inventiveness, although the significance of that contribution depends on the facts. Routine simulations do not establish obviousness unless the evidence shows that they would have identified both the relevant problem and the claimed solution without hindsight. A prior document must be read through the skilled person’s common general knowledge and the technical context existing at the relevant date.

The claimants alleged that EP(UK) 2 421 318 B1, concerning transmission of Scheduling Information in HSUPA systems, was essential to the relevant telecommunications standard. The defendants challenged validity on anticipation and obviousness grounds based on the Prior MAC Specification and Kim, a US patent application. The principal construction issue concerned the meaning of “in response to” in claim 1. The court also considered whether the transmission-blocking problem would have been identified through mapping exercises or routine simulations, and whether Kim disclosed the claimed trigger when read by the skilled person with HSUPA common general knowledge.

1. Construction. The expression “in response to” in claim 1 referred to the new trigger condition described in the patent: sending Scheduling Information when a non-zero grant was too small to permit transmission of a single PDU from a scheduled MAC-d flow. The broader construction advanced by Lenovo would have caused the claim to cover acknowledged prior art and common general knowledge. It was therefore rejected as inconsistent with the patent’s context and purpose.
2. Essentiality. The claim was essential to section 11.8.1.6.2 of TS 25.321. The trigger did not arise where the buffer was empty or where transmission was prevented by power limitation rather than the size of the Serving Grant. The claim did not require repeated transmission in every TTI while the condition persisted.
3. PMS. The anticipation case failed because the PMS did not disclose the claimed trigger. The obviousness case also failed. Although implementation required routine simulations and optimisation, the evidence did not establish that the skilled person would have identified the transmission-blocking problem and its solution without hindsight. The absence of pre-priority proposals identifying the problem or solution was significant.
4. Kim. Read with HSUPA common general knowledge, Kim’s Figure 9 embodiment did not disclose Scheduling Information being sent in response to a non-zero grant too small to transmit a MAC-d PDU. The contrary reading depended on hindsight and on treating Kim as displacing the established HSUPA E-TFC selection process. The obviousness case based on Kim therefore failed.
5. Claim 2 remained inventive. Claim 4 was not inventive over claim 2, since allowing the network to configure the periodicity was common general knowledge. The patent was held valid and essential.