In October 2020, as part of the wider battle currently on foot in the courts between Optis Cellular Technology LLC and Apple Retail UK, Mr Justice Birss (as he then was) ruled that one of the European (UK) Standard Essential Patents in contention owned by Optis was valid, essential to certain releases of the 2G standard and had been infringed by Apple through its dealings in iPhones and iPads.

The patent was entitled “Method for improving handovers between mobile communications systems” (the Patent). It had a priority date of 17 November 1999 and expired on 20 October 2020.

The invention claimed in the Patent related to handover between different Radio Access Technologies (RATs) such as GSM (2G) and UMTS (3G). Although the specific embodiment described in the Patent concerned handover from GSM to UMTS, the claims were not limited to that scenario, as illustrated by the fact that the alleged infringements encompassed handover from GSM to LTE (4G).

Apple appealed Birss J’s decision, contending that the Patent was invalid and in any event was not essential and therefore had not been infringed.

Apple had originally challenged the validity of the Patent on the ground that it was Agrevo obvious, as it contained an alleged arbitrary limitation in the claim. Birss J had dismissed Apple’s initial claim, finding that conversion was not arbitrary. Apple challenged this finding. Giving the lead judgment, with which the other Justices agreed, Lord Justice Arnold dismissed Apple’s arguments and upheld Birss J’s decision.

As for essentiality, the issue was whether the priority level 3 method specified in the standard involved “converting” a plurality of downlink measurement values associated with UMTS to a plurality of downlink measurement values for GSM and sending those converted values to the GSM network, given the judge’s construction of “converting” as having two aspects, namely formatting and direct comparability.

Apple contended that Birss J should have concluded that Optis had failed to establish that the standard involved conversion of the UMTS values to ensure direct comparability.

Considering Apple’s challenges to Birss J’s findings, Arnold LJ concluded that Optis had indeed failed to demonstrate that the standard involved conversion of the UMTS values in order to ensure direct comparability with the threshold value used in priority level 3.

It followed that the Patent was not essential to the standards in issue, and that therefore Apple had not infringed the Patent. (Optis Cellular Technology LLC v Apple Retail UK Ltd [2021] EWCA Civ 1619 (10 November 2021) — to read the judgment in full, click here).