An Efficient Low-Complexity Detector for Spatially Multiplexed MC-CDM

We propose a novel suboptimum detection method for spatially multiplexed multicarrier code division multiplexing (SM-MC-CDM) communications. Compared to the spatially multiplexed OFDM (SM-OFDM), the frequency domain spreading in SM-MC-CDM systems results in an additional diversity gain. To take advantage of diversity and multiplexing while mitigating interference, we design a low complexity efficient detector called unified successive interference cancellation (SIC) detector for SM-MC-CDM communications. Further performance improvement is achieved by adopting in conjunction with the unified SIC the iterative subcarrier reconstruction-detection algorithm originally proposed for single antenna systems. The results demonstrate significant performance improvement over other existing methods of comparable complexity. A close approximation for the probability density function (pdf) of the proposed detector's output signal-to-interference plus noise ratio (SINR) is found and used to obtain error bounds for the bit error rate (BER). Performance of the coded SM-MC-CDM transmission is also discussed in the paper.