Modern wireless communications require an efficient spectrum usage and high channel capacity and throughput. Multiple input and multiple output (MIMO), Linear equalizers, multi-user detection (MUD) and multicarrier code-division multiple access (MCCDMA) are possible solutions to achieve spectral efficiency, high channel capacity, eliminate MAI , eliminate ISI and robustness against frequency selective fading. In this paper, we combine all these techniques and investigate BER performance. We propose a low complexity receiver structure for Single-input Multiple-output (SIMO) downlink
MC-CDMA systems. It employs an interference cancellation scheme to suppress the interference caused by the multipath fading channel. Also, the proposed scheme is developed for Multiple-input Multiple-output (MIMO) MC-CDMA system. The
performance analysis of Downlink MIMO MC-CDMA systems with V-BLAST over frequency selective fading channel is investigated under various number of transmit and receive antennas. The simulation results show that MIMO MC-CDMA with V-BLAST multi-user detection provides high data rate and the BER significant improvement when MIMO-MC CDMA with multi user detection and different linear equalizers is applied.