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  1. Technology
November 8, 1993


By CBR Staff Writer

InterDigital Technology Inc, the King of Prussia, Pennsylvania-based company engaged in lawsuits against L M Ericsson Telefon AB and Oki America Inc in the US for alleged Time Division Multiple Access patent infringements, has had the validity of its basic German TDMA system patent confirmed by the German Patent Office. After being granted on June 28 1990, the German patent was opposed by Philips Patentverwaltung GmbH, Standard Elektrik Lorenz AG and Siemens AG. As a result, the validity of the InterDigital patent was scrutinised by a panel of three senior patent examiners, who have found in InterDigital’s favour. President and chief executive of InterDigital Robert Bramson says the fact that the German patent has withstood the review after opposition by three major European communication companies, together with the prior approval of its basic TDMA system patent claims in proceedings filed by Nokia Cellular Systems Oy in the Finnish Patent Office, is extremely encouraging. Bramson added that the decisions have reinforced the company’s judgement that its TDMA systems patents are valid, increased its resolve to go forward vigorously with the US lawsuits, and renewed its determination in granting royalty-bearing, non-exclusive licences for its portfolio of 450 domestic and foreign TDMA patents. An Ericsson spokesman said that the German decision did not affect its case in the US, which is based on the twin propositions that certain of InterDigital’s TDMA patents are irrelevant to its equipment and that others are invalid because they cover technology in the public domain. However, he added that the opponents in the German patent case were filing an appeal against the decision.

Public domain

David Barrett, head of Information Technology and Telecommunications Law at London law firm Dibb Lupton Broomhead, broadly supports the Ericsson stance that technology in the public domain cannot be patented. He says that it is a fundamental legal principle that one can only patent an innovation and, by definition, anything in the public domain is not an innovation. Speaking generally, Barrett adds that if something is part of an existing standard, that will strengthen the case for it being in the public domain. InterDigital refutes this, describing it as a common defence in cases such as these. The company’s position is that InterDigital pioneered TDMA and that the whole way you do TDMA is dependent on our patents. Ericsson’s response is that it has thought its position through very carefully and believes it is correct in its defence. It also asserts that its customers remain confident in the company and that sales have not been affected by the forthcoming litigation. Both companies are keeping the specific details of their cases under wraps, but part of Ericsson’s defence may hinge on the fact that TDMA is basis of the Groupe Speciale Mobile standard for digital cellular communications: the US Cellular Telecommunications Industry Association endorsed TDMA in early 1990, placing it firmly within the disputed public domain. If InterDigital wins its lawsuit against Ericsson, it will have major implications for all vendors of Time Division Multiple Access cellular equipment: the patents are not specific to the equipment made by the vendors that are being sued, but are central to the concept of Time Division Multiple Access itself. InterDigital’s patents were taken out between 1985 and 1992 and will run for 17 years. Regarding other companies involved in TDMA, InterDigital says it will ‘wait and see’ what happens in court – a statement carrying clear implications that it will be after them as well if it wins.

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