Multiuser Receiver Scheme for a Full-rate Space-time Block Coded CDMA System

By introducing full-rate space-time block coding (STBC) scheme, a full-rate space-time block coded CDMA (FSTBC-CDMA) system for downlink in time division duplex mode is given. Considering that existing space-time coded CDMA system has high decoding complexity, a low-complexity multiuser receiver scheme is also proposed. The scheme can make full use of the complex orthogonality of STBC to simply the high decoding complexity of the existing scheme after multiuser detection method is employed to suppress multiuser interference effectively; it has linear decoding complexity when compared with the existing scheme. Moreover, compared with full-diversity space-time block coded CDMA, our given FSTBC-CDMA system can implement full rate, low complexity and partial diversity, has more spatial redundant information. Thus the concatenation of channel coding can effectively make up for the performance loss due to partial diversity. Simulation results show that the proposed FSTBC-CDMA system has lower bit error rate (BER) than those low-rate and full-diversity space-time block coded CDMA system on the condition of same system throughput and concatenation of channel code