James Abrahams KC, James Whyte and Michael Conway appeared for the Appellants (“Optis”) and Lindsay Lane KC (together with Adam Gamsa) appeared for the Respondents (“Apple”) in an appeal from the Order of Meade J revoking Optis’s patent following Trial C in the proceedings between the parties. The patent claimed a method of allocating space on the downlink control channel (the PDCCH) to UEs in a cell, which involved use of a particular random number generator called a Linear Congruential Generator (“LCG”). At trial it was not disputed that the claimed method was essential to the LTE mobile telecommunications standard.
Meade J had found that the patent was invalid for obviousness over slides presented at a RAN1 meeting (“Ericsson”). On appeal Optis argued that the Judge had made several errors of principle in his assessment of how the skilled person would arrive at the patented solution starting from the proposal in Ericsson.
The Court of Appeal allowed the appeal by a majority. An essential step in Apple’s obviousness case was that the Skilled Person would have consulted a textbook, “Numerical Recipes in C” (NRC) which contained warnings against using LCGs. Arnold LJ, with whom Nugee LJ agreed, held that on its proper interpretation NRC clearly taught away from the use of LCGs. He held that the Judge had made an error of principle in finding that the Skilled Person would have ignored those warnings and considered that an LCG was suitable nonetheless. The Judge had not identified any sufficient basis for reaching that conclusion. In his dissenting judgment, Birss LJ held that the skilled person’s attitude to LCGs would not have been based solely on NRC. He held that the Judge had been entitled to conclude that the skilled person had sufficient skill and knowledge to decide that LCGs could still be useful for the application they had in mind.