Performance of iterative multiuser decision-feedback receivers

We compare the performance of iterative multi-user successive and parallel decision feedback detectors (DFDs) for code-division multiple access (CDMA). An adaptive successive-DFD (S-DFD) is first presented, which requires only a training sequence and associated timing to estimate all filter coefficients. Simulation results show that with limited training, the adaptive S-DFD performs significantly better than the adaptive parallel-DFD (P-DFD). A large system analysis of error rate for non-adaptive iterative DFDs is also presented, and shows that the S-DFD converges with fewer iterations than the P-DFD.