An iterative receiver for layered space-time MIMO DS-CDMA uplink using turbo trellis-coded modulation

An iterative turbo receiver is proposed for the uplink of a MIMO CDMA system employing layered space-time transmission. The proposed receiver consists of a low-complexity layered space-time multiuser detector using linear minimum mean squared error (MMSE) filtering with a-priori information and parallel a-posteriori probability (APP) computing soft-input soft-output (SISO) decoders. Turbo trellis-coded modulation (TTCM) is used as error-correcting tool to achieve bandwidth efficient transmission. Computer simulation results show that the proposed receiver using an iterative operation along with the detector and decoders outperforms an iterative receiver based on parallel interference cancellation as well as a non-iterative MMSE receiver. Furthermore, while providing an increase in system capacity, the proposed receiver offers an error performance similar to that of the single-user case at high SNR, in a multiuser environment.