Performance of Iterative DS-CDMA M-ary Demodulation in The Presence of Synchronization Errors

The robustness of different interactive schemes for demodulating M-ary orthogonal signaling formats in asynchronous DS-CDMA systems to the synchronization errors is addressed. The system under study resembles the uplink of an IS-95 system. The channel is assumed to be a time-varying flat Rayleigh-fading channel. Our simulation results show that the performance degradation for the considered multi-user detectors increase linearly with synchronization errors and eventually converge to that of conventional matched filter. In order to see the impact of channel estimation on the performance of multi-user detectors, we made some comparisons between non-coherent and coherent variants of the detection algorithm