IP analysis: On 25 April 2023, the Court of Appeal handed down its judgment in technical trial C in the Optis v Apple SEP/FRAND litigation, 17 months after the first instance decision of Mr Justice Meade dated 25 November 2021. In a split decision with a leading judgment by Lord Justice Arnold and a dissenting judgment by Lord Justice Birss, the court allowed Optis’s appeal and set aside the revocation of three patents of the same patent family, each concerned with radio resource allocation on the Physical Downlink Control Channel (PDCCH), and in particular concerning a mathematical function to prevent ‘collisions’ and ‘blocking’. The court considered eight grounds of appeal brought by Optis by reference to claims 1 and 4 of EP 2 093 953 (the ‘Patent’). Ultimately, the court allowed the fifth ground of appeal, finding that the claims were therefore inventive over the prior art, meaning that yet another of Optis’ patents in these proceedings has been found valid, essential and infringed (Apple accepted from the outset that, if valid, the Patent would be essential and therefore infringed). Written by Neville Cordell, partner, and Sian Avery, associate, at Allen & Overy LLP.