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The Qualcomm CDMA Digital Cellular System

Phil Karn
Qualcomm, Inc.


Qualcomm, Inc. has developed and tested a digital spread spectrum cellular telephone system that will supplant and evetually replace the existing analog FM cellular system. TIA has recently standardized this "CDMA" (Code Division Multiple Access) as TIA IS-95, and several cellular carriers have already announced plans to deploy the services.

The original impetus for CDMA;s development was the enormous popularity of existing narrow band analog FM cellular telephone systems. There is only so much radio spectrum available to deal with the flourishing demand for cellular service, and severe congestion already exists in several major service areas. A IS-95 system can carry about 10-15 times as many voice calls as an analog system in the same spectrum.

Although Qualcomm specifically designed IS-95 for voice telephony, it is easily adapted to packet data transmission. It can provide a service comparable to those of several existing and proposed metropolitan area wireless data networks with better performance, greater reliability, and lower cost.

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