GM Unit Makes Cellular Telephone Breakthrough

GM Hughes Electronics has developed technology it says will increase the capacity of cellular phone systems fifteen-fold--a boon to overcrowded systems in cities such as New York and Los Angeles.

The entrance of the General Motors Corp. subsidiary into the race for the next-generation cellular technology appears promising, but it will only increase an industry battle over which system eventually will be used, industry analysts said.

The Cellular Telecommunications Industry Assn., the industry’s main trade group, already has approved specifications for a digital technology that would replace today’s analog cellular phones.

But the most advanced digital phone system envisioned by the trade group would only increase capacity six times--below the tenfold increase the nation’s cellular phone operators say they will need to meet expected demand.

The trade group announced late Monday that nine large cellular phone equipment makers agreed to a timetable for readying digital phone gear. Under it, prototype equipment will be tested by March 31.

The companies are Motorola Inc., American Telephone & Telegraph Co., Ericsson, Audiovox, Mitsubishi, NovAtel, OKI Telecom, Sony and Uniden.

Hughes’ digital system, to be formally announced today, is based on a technology called time-division multiple access, which allows several calls to be sent simultaneously over the same channel.