On 21 December 2007 the English High Court handed down a decision in Nokia Corporation v Interdigital Technology Corporation in which Nokia sought to establish that some of Interdigital’s patents were not essential to the third generation (3G) mobile communications standard in Europe.

Out of the 29 patents that Interdigital informed the European Telecommunications Standards Institute (ETSI) were essential to the standard, just four patents remained in contention by the time the matter came to trial.

The relief sought by Nokia was a declaration that the importation, disposal of, offer to dispose of, keeping or use of (i) mobile telephones and (ii) system infrastructure equipment compliant with the standards but without an Interdigital licence does not infringe on the patents. In addition, Nokia sought a declaration that the patents are not essential for the employment of the 3G mobile standard.

The 3G standard was established by the Third Generation Partnership Project (3GPP). The patents at stake concern the method by which data is transmitted between the mobile and the base station by using wideband code division multiple access (WCDMA).

The first patents examined by the Court were EP (UK) 0515610 (610) and EP (UK) 0855807 (807), both are concerned with power control. Their specifications are identical but the claims differ. At the time of the priority date of 610, no working CDMA was publicly available. The invention concerned an apparatus and the relevant method for adaptive-power control of a spread spectrum transmitter of a mobile station operating in a cellular communication network and an apparatus and method for automatically controlling the power level of a plurality of mobile stations. The relevant features of the 3GPP standard are those concerning the way the protocol is employed during the random access procedure that states how a mobile makes itself known to a particular base station at the physical level: the mobile sends a “preamble” signal at a certain power level over the physical random access channel (PRACH) and if the “preamble” is not recognised by the base station, the mobile increases the power and repeats the process.

After a deeply technical examination and comparison between the standard rules and the claims, the Court held that, while the relevant apparatus claim would not be infringed by an apparatus carrying out the process set out in the standard, the last feature of the relevant method claim, “adjusting a transmitter-power level of a transmitter spread-spectrum signal for a respective transmitter responsive to said comparison signal”, would have covered the process specified in the standard of effecting open loop power control in the physical random access procedure, therefore, , to this extent, the invention was essential to the 3GPP standard.

The Court also considered EP (UK) 1210777 (‘777), entitled “Transmission using an antenna array in CDMA communication systems” which is concerned with transmitting a signal from more than one antenna sufficiently spaced apart. The invention refers to a base station using an antenna array to transmit signals to mobiles. Each antenna sends a version of a pilot signal and every mobile weighs and combines those versions providing a signal with an improved quality. All the discussions related to ‘777 were focussed on claim 1 concerning the method in a spread communication system having several antennae. The Court examined the features of the claimed invention and ultimately the Court did not consider them essential features. A similar decision was reached in relation to all other the patents, i.e., the features were not considered essential to the 3GPP standard.

Thus only one patent, namely the ‘610 patent, was accepted by the Court as being essential to the 3GPP standard. Nevertheless, this will remain a problematic area as all future licensing terms will have to take this decision into account when parties claim the free usage of the 3GPP standard by all handsets.