An iterative MMSE-decision feedback multiuser detector for space-time coded multicarrier CDMA system

Performance of wireless communication systems is primarily limited by multipath fading effect of the radio channel and multiple-access interference caused due to other users in the system. Two promising techniques to counter these problems are space-time coding and iterative multiuser detection. In this paper, an iterative receiver structure for space-time block coded MC-CDMA system employing multiple transmit and receive antennas is presented. The receiver is based on the minimum mean square error decision feedback multiuser detection. The log-likelihood ratios computed by the soft multiuser detector are refined successively during the iterative process by using the extrinsic information available through decoding of all users. Turbo code is used for channel coding. Simulation results in a frequency selective Rayleigh fading environment are presented to verify the performance of the proposed scheme.