Iterative multi-user-antenna detector for MIMO CDMA employing space-time turbo codes

In this paper a synchronous multiple-input multiple-output (MIMO) uplink CDMA system employing space-time turbo codes is considered. We introduce a multiuser-antenna receiver structure to detect the multiuser and multi-antenna signal in this system. The linear minimum mean-squared error (MMSE) detector and an MMSE-based turbo parallel interference cancellation (PIC) detector are respectively utilized to suppress the multiple access interference (MAI) between users and the crosstalk between antennas at the same time. In the turbo PIC detector, the soft output of the space-time turbo decoder is fed back to improve the PIC´s performance. Using computer simulation, we examine the multiuser-antenna detectors´ performance in the block Rayleigh flat fading channel. The simulation results suggest the two multiuser-antenna receivers can both combat the interference between different users and antennas. However the iterative detector achieves a substantial performance gain over the MMSE one.