Performance analysis of space-time diversity adaptive PIC for multipath CDMA channels

In this paper, a low complexity space-time multiuser detector that combines the antenna array with adaptive parallel interference cancellation (PIC) in a multipath fading channel is proposed. By beamforming, the signal-to-interference-ratio (SIR) increases which results in a lower BER in the initial stage of PIC. For in-beam multiple access interference (MAI) reduction, a nonlinear adaptive PIC with gradient adaptive step size is introduced based on a modified normalized least mean square (MNLMS) algorithm. The computational complexity of the approach is linear with the number of the active users. Simulation results show the excellent performance of the proposed scheme in comparison with the existed linear ST-MMSE receiver.