Turbo Multiuser Detection for LDPC Coded MC-CDMA Systems

This paper investigates the performance of LDPC coded MC-CDMA systems. Turbo multiuser detection is exploited by combining per-user MMSE-PIC detection and LDPC decoder together. In this way, error propagation can generally be averted for lower number of subcarriers. Simulation results show that the proposed scheme achieves about 4 dB coding gain for 256 subcarriers at BER = 10^-4. The performance degrades only slightly with smaller spreading factors per MC-CDMA multiplex. Thus, from practical point of view, smaller spreading factors can be utilized to reduce the complexity of the detector as a whole