SUCCESSIVE BEAMFORMING, MULTIUSER DETECTION AND DIVERSITY RECEPTION FOR MULTICARRIER DS-CDMA SYSTEM WITH ANTENNA ARRAY

摘要

Code-Division Multiple-Access (CDMA) systems are interference limited, and therefore efficient interference management is necessary to enhance the performance of a CDMA system. In this paper, a successive beamforming (spatial filtering), linear decorrelating MultiUser Detection (MUD,temporal filtering) and diversity reception structure for uplink multicarrier Direct Sequence CDMA (DS-CDMA) system with antenna array are proposed. By beamforming, the antenna array suppresses interference according to the distinct array signature. Subsequently, linear decorrelating MUD is applied to separate the signals of different users and eliminate Multiple Access Interference (MAI). Finally,the decorrelated signals at different subcarriers that belong to the same user are combined to achieve frequency diversity. Simulation results show that the proposed structure offers significant Bit Error Rate (BER) performance improvement by successively exploiting the space-time-frequency processing.