A Particle Filter of Blind Equalization and Multiuser Detection in Asynchronous DS/CDMA Systems

The particle filter(PF)is proposed to be the asynchronous direct-sequence code-division multiple-access(DS/CDMA)multiuser detector without knowing the channel state information.The PF performs symbol detection according to the joint posterior density probability of simulated particles including relative delays,fading gains and symbols via sequential importance sample and resample.A simplified scheme is also proposed by separating the independent relative delays and fading with symbols.These parameters are modeled as the extended aggressive processes and estimated by the Kalman filter,so as to provide their arbitrary importance distribution for symbol detection.Simulation results show that the bit error rate of the PF is less than conventional detectors.Moreover,the complexity of PF is moderate comparable to other nonlinear suboptimal approaches.