Performance analysis of an iterative group-wise parallel interference cancellation for multiuser detection of coherent W-CDMA system

We present performance analysis of an iterative group-wise parallel interference cancellation (IGPIC) algorithm for coherent detection of an asynchronous wideband DS-CDMA system in a single cell over multipath Rayleigh fading channels. The proposed IGPIC algorithm can improve the existing serial interference cancellation (SIC) algorithm that significantly degrades the detection performance for stronger users compared to weaker users. It also improves the group-wise serial interference cancellation (GSIC) algorithm that suffers from severe degradation of detection performance as the number of users in a group increases. In the proposed algorithm, users in a system am divided into several groups and interfering signals are subtracted out from the received signal as many times as the number of users in a group, iteratively. The iterative group-wise interference cancellation (IGIC) algorithm is also classified into the iterative group-wise serial interference cancellation (IGSIC) and the IGPIC algorithm. The results show that the performance of the IGPIC algorithm is superior to that of the IGSIC algorithm by 4 dB, right before the final cancellation in a group for 10 users at BER=1.0×10^-2.