Abstract:The performance of Maximum Likelihood Detector (MLD), decorrelating detector which based on multi-code detections and MMSE Multi-User Detector(MUD) of MIMO CDMA system under Rayleigh fading channels were analyzed in the paper. The relation between the number of antennas and system capacity at a given SNR was also analyzed. The numerical results present that the capacity is degressive for MMSE MUD, MLD with interference covariance known, MLD with interference covariance unknown, and decorrelating detector, furthermore the three latter detectors all have platform as SNR is large; at a given SNR, the relation of system capacity and the number of antenna is linear for a N×N system.