Adaptive space-time feedforward/feedback detection for CDMA

We investigate linear and nonlinear minimum mean-square error (MMSE) multiuser detectors for high data rate wireless code-division multiple access (CDMA) networks. The reverse link spacetime detectors comprise an antenna array followed by a feedforward filter (FFF) which processes parallel chip matched filter (CMF) output samples and a feedback filter (FBF) which processes detected symbols of all in-sector users. We explore adaptation issues, calculate outage probabilities, and isolate the effects of antenna, diversity, and interference suppression gains for Rayleigh and Ricean multipath fading channels with varying timing control.