Approximation of an integrated CDMA system

There is a limited amount of RF spectrum that has been allocated by the FCC to cellular communications (800-900 MHz and 1.8-2.0 GHz). To increase capacity, the only alternatives available, in lieu of increasing available RF spectrum, are to invent new technology or to more efficiently use the currently available technology. The Telecommunication Industry Association (TIA) has standardized CDMA as TIA Interim Standard 95 (IS-95). IS-95 systems can carry about 10-15 times as many voice calls as an analog system in the same spectrum. It is well known that voice communications consists of both talkspurts and silent periods. Talkspurts consist of only 40 percent of the call, the remaining 60 percent of the call is silence. The authors are studying the reallocation of silent periods to a lower grade of data users in an attempt to integrate voice and data users in a CDMA system and to maximize use of the available RF spectrum.