Performance of EM-based multiuser detection for space-time block coded WCDMA systems over multipath fading channels

We present a multiuser detection (MUD) scheme derived from the expectation maximization (EM) algorithm for the downlink of space-time block coded (STBC) WCDMA systems. We consider the downlink scenario with two transmit antennas and a single receive antenna and multipath fading channels. The EM-based MUD looks iteratively for the maximum-likelihood solution. Its structure is very similar to the parallel interference cancellation (PIC) receiver but with better convergence properties. Our simulation results show significant performance gains over conventional and PIC receivers.