Iterative multiuser receiver for a coded DS-CDMA system

A new iterative multiuser receiver structure for a direct-sequence code division multiple access (DS-CDMA) system with forward error correction (FEC) coding is proposed. This structure employs the turbo multiuser detection principle in a soft multi-access interference cancellation scheme. The receiver first uses a Wiener filter to demodulate and de-spread the received signal, this process yields the initial coded data estimates. Based on these estimates, the parallel cancellation scheme and the channel decoding are coupled to exchange soft information in an interactive fashion. Simulation results show that performance approaches the single-user performance even in highly loaded systems. It is also shown that the use of Wiener filtering on the first iteration of the iterative receiver yields a substantial performance gain in the system.