Performance of a PSO assisted PPIC for SDMA/OFDM overloaded system

In this work, a novel particle swarm optimization (PSO) assisted Joint Channel Estimation and Partial Parallel Interference Cancellation (PSO-JCEPPIC) detector is adopted for multiuser Multiple-Input Multiple-Output/Space Division Multiple Access (MIMO-SDMA) Orthogonal Frequency Division Multiplexing (OFDM) systems. The proposed PSO-PPIC scheme tries to reduce the cancellation error in Conventional Parallel Interference Cancellation (CPIC) detection schemes used in MIMO SDMA-OFDM system. The PSO algorithm is employed in searching the optimal weights of the PPIC for multiple access interference cancellation. The proposed scheme is shown to provide a performance improvement as compared to MMSE and CPIC detectors especially in an overloaded scenario where the number of users is high as compared to the base station (BS) antennas. In this scenario, the channel coefficients become more difficult to be estimated, due to the high number of independent channel links and the constraint imposed by the MIMO channel matrix rank. The proposed PSO-JCEPPIC scheme presents an efficient solution to the multiuser detection and the MIMO channel matrix estimation dilemma in the previously mentioned scenario.