Performance of PSO and SA assisted joint scheme of channel estimation and PPIC in MIMO-SDMA/OFDM over-loaded system

In this paper, a novel Joint Channel Estimation and Partial Parallel Interference Cancellation (PPIC) scheme using Simulating Annealing (SA) or Particle Swarm Optimization (PSO) algorithms is proposed. This scheme is proposed for multiuser Multiple-Input Multiple-Output / Space Division Multiple Access (MIMO-SDMA) Orthogonal Frequency Division Multiplexing (OFDM) systems. The SA and PSO algorithms are 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 number of users exceeds the Base Station (BS) antennas. In overloaded scenario, the channel coefficients become more difficult to be estimated, due to the difficulties imposed by the MIMO channel matrix rank. The proposed scheme presents an efficient solution to the multiuser detection and the MIMO channel matrix estimation dilemma in overloaded scenario.