Adaptive equalizers for joint detection in an indoor CDMA channel

Abstract

Direct sequence CDMA (DS-CDMA) is a candidate access technique for a third generation mobile system. This paper deals with adaptive joint detection techniques for a synchronous indoor code division multiple access (CDMA) system. Multiple access interference (MAI) is combated through adaptive equalization while intersymbol interference (ISI) is suppressed by introducing a guard interval before the transmission of an information symbol. We present two symbol by symbol multiuser detectors: the linear equalizer and the decision feedback multiuser detector. Our simulation results show that the performance of these detectors are greatly superior to that of the conventional receiver consisting of a bank of matched filters. The decision feedback detector is also shown to perform better than the linear detector.