E-TDMA: high capacity digital cellular radio

First-generation US digital cellular radio will use digital speech compression and time-division multiple-access (TDMA) to carry three voice circuits on each duplex 30-kHz radio channel pair, as compared to one voice circuit for analog cellular radio. The TDMA structure provides for expansion to six voice circuits per RF channel. Further capacity increases can be achieved by using digital speech interpolation (DSI) to provide the equivalent of ten or more voice circuits per RF channel. A cellular system capacity metric is presented. Using the metric, the capacities of analog and full- and half-rate digital access methods are compared in an interference-limited environment. An implementation of DSI and half rate speech, called extended-TDMA (E-TDMA), is compared with analog and the other digital techniques