Koninklijke Philips NV v Asustek Computer Incorporation & Ors

A patent claim is not obvious merely because a skilled person could identify a technically possible alternative to the prior art. The court must assess whether the skilled person would have been motivated to adopt that alternative, having regard to the disclosure, common general knowledge and practical implementation issues at the priority date.

Where prior art discloses a theoretical optimisation, uncertainty about its real-world benefits and the complexity of adapting its implementation may support non-obviousness. The court must assess the evidence as a whole and avoid hindsight. A later foreign decision on the same issue is informative but does not displace an assessment based on the evidence and arguments before the court.

The claimant owned a European patent relating to a radio communications system, particularly acknowledgement and negative-acknowledgement signalling in HSDPA. It alleged that the defendants’ HSPA-compatible mobile phones infringed the patent. The trial concerned validity of the patent, with infringement and essentiality not in issue.

The defendants contended that claim 10 was obvious over two items of prior art: Motorola 021 and Shad. The central issues were whether the claimed differential power levels for ACK and NACK signals, with the power indication signalled from the base station to the mobile station, were obvious in light of either disclosure.

1. Claim 10 was valid. It was not obvious over either Motorola 021 or Shad. The patent had been infringed by the defendants.
2. Motorola 021 disclosed an uplink control-channel structure using BPSK, repetition coding and a separate gain control for the ACK field. It did not disclose differential powers for ACKs and NACKs. Differential powers in binary antipodal signalling were not common general knowledge at the priority date. The defendants’ argument that differential gains were an obvious alternative was materially influenced by hindsight.
3. The skilled person would also have regarded Motorola 021 as capable of achieving its target error rates at a reasonable signal-to-noise ratio. There was therefore no motivation to change its approach. The pre-priority-date standards material was more consistent with non-obviousness than obviousness.
4. Shad disclosed unequal gains for ACK and NACK signals and optimisation of the gains and receiver threshold, but it did not disclose that the base station signalled the gain values to the mobile station. Although the skilled person would not simply disregard Shad, adapting its implementation in the claimed manner involved unresolved practical questions concerning error statistics, channel conditions, look-up tables, signalling and system complexity.
5. The evidence did not establish that the skilled person would make the necessary changes while retaining Shad’s proposed differential-gain approach. The arguments were finely balanced, but the defendants had not satisfied the court that the claim was obvious.
6. The decision of the District Court of The Hague holding claim 10 obvious over Shad was respected but was based on different evidence and arguments. The court therefore reached its own decision on the material before it.