CDMA cellular mobile system capacity improvement by combination with TDMA and adaptive interference suppression

This paper proposes a cellular mobile system employing a combination of time division multiple access (TDMA), to multiplex users within a cell, and code division multiple access (CDMA), to control interference between cells. An important aspect of the system design is the use of an adaptive receiver for multiple-access interference suppression. The effectiveness of the adaptive interference suppression is assured by the increased data rate and low spreading ratio afforded by the time division multiplexing of user signals. As a basis for comparison, a model for the reverse channel of the IS-95 cellular CDMA standard has been developed. Both systems were simulated using a multipath fading channel model, with additive white Gaussian noise (AWGN) and multiple access interference. The proposed system is shown to exhibit superior system capacity, and has inherent advantages for system synchronization.