Performance of Turbo Interference Cancellation Receivers in Space-Time Block Coded DS-CDMA Systems

We investigate the performance of turbo interference cancellation receivers in the space time block coded (STBC) direct-sequence code division multiple access (DS-CDMA) system. Depending on the concatenation scheme used, we divide these receivers into the partitioned approach (PA) and the iterative approach (IA) receivers. The performance of both the PA and IA receivers is evaluated in Rayleigh fading channels for the uplink scenario. Numerical results show that the MMSE front-end turbo space-time iterative approach receiver (IA) effectively combats the mixture of MAI and intersymbol interference (ISI). To further investigate the possible achievable data rates in the turbo interference cancellation receivers, we introduce the puncturing of the turbo code through the use of rate compatible punctured turbo codes (RCPTCs). Simulation results suggest that combining interference cancellation, turbo decoding, STBC, and RCPTC can significantly improve the achievable data rates for a synchronous DS-CDMA system for the uplink in Rayleigh flat fading channels.