Iterative sequential multiuser receiver for asynchronous coded CDMA systems over frequency-selective fading channels

This paper investigated a reduced complexity iterative multiuser detector based on sequential sequence estimation technique for joint detection and decoding of asynchronous code division multiple access (CDMA) signals over frequency-selective fading channels. The soft-input soft-output (SISO) multiuser detector is realized by the soft-output sequential algorithm (SOSA), previously introduced for turbo equalization systems. The advantage of this scheme comes from the low complexity of the sequential algorithm, which is only linearly dependent on the number of users. Simulation results show that the iterative sequential multiuser detector can achieve a significant performance gain over the conventional single-user detector as well as the multistage interference cancellation (MIC) receiver, and that it suffers a small amount of degradation compared with the single user performance.