Trellis coding with diversity for DS-SS CDMA communication over indoor radio channels

Direct sequence spread spectrum (DS-SS) is an efficient method to combat multipath fading and interference, especially when combined with mitigation techniques like channel coding and diversity. The authors evaluate bounds to the performance of trellis codes in combination with conventional diversity for a DS-SS code division multiple access (CDMA) system in the indoor environment, modeled by a slowly varying, Rayleigh fading, discrete multipath channel. A Gaussian approximation for the multiuser interference, a star network configuration, and average power control are assumed. The index of performance is the average bit error probability. It is shown, for a given average error probability, that there is considerable improvement in the number of users supported by the subject system when compared with systems with either coding or diversity alone