A fuzzy PIC multiuser detection/vector channel estimation scheme in Rayleigh fading channels

We propose a fuzzy parallel interference cancellation (PIC) multiuser detection/vector channel estimation (VCE) scheme in Rayleigh fading channels. The VCE is based on a first-order auto-regressive model and an expectation-maximization algorithm. The signal-to-interference ratio and signal-to-noise ratio are estimated from the vector channel model's parameters, and we adapt the weight of each interference cancellation path via fuzzy inference mechanism. The proposed fuzzy PIC and VCE cooperate in a way such that some of the fuzzy PIC input parameters come from the channel predictor and the fuzzy PIC makes the channel predictor be more accurate at the next PIC stage. Computing weights via fuzzy adaptive method adds insignificant complexity because it involves only table lookup. The simulation results show that the proposed fuzzy PIC/VCE scheme performs better than the improved PIC/vector channel estimation scheme with optimal parameter in fast-varying Rayleigh fading channels.