Interference cancellation based multiuser receiver with channel decoding and decision feedback in asynchronous CDMA systems

Due to the poor performance of conventional receivers with multiple access interference and the near-far problem, we propose an interference cancellation based multiuser receiver with channel decoding and decision feedback for asynchronous CDMA systems. The proposed receiver consists of a RAKE receiver, multiuser detector, multiple access interference cancellation, soft-decision channel decoder and decision feedback from the decoder. The conventional and our generalized multistage multiuser detectors are both simulated in the proposed receiver. The simulation results show that the interference cancellation based receiver significantly outperforms the traditional receiver. The performance of our generalized detector without feedback approaches or even exceeds the performance of the conventional multistage detector with feedback. It means that 50% of the implementation complexity can be saved. Furthermore, the processing delay of the interleaving introduced by decision feedback can also be avoided.