Timing-free blind multiuser detection for multicarrier DS/CDMA systems with multiple antennas

The problem of blind multiuser detection for an asynchronous multicarrier DS/CDMA system employing multiple transmit and receive antennas over a Rayleigh fading channel is considered in this paper. The solution that we develop requires prior knowledge of the spreading code of the user to be decoded only, while knowledge of the propagation delay and of the channel impulse response for the user of interest is not required at the receiver. The proposed receiver is immune to co-channel interferers transmitting with an arbitrarily large power and, as computer simulation results confirm, performs pretty close to the ideal linear minimum mean square error receiver, which requires knowledge of the spreading codes, symbol timings and channel impulse responses for all the active users.