A Low-Complexity Parallel Interference Cancellation for DS/CDMA Systems over Rayleigh Fading Channel

This paper firstly investigates an optimal parallel interference cancellation (PIC) scheme for an asynchronous DS/CDMA system. Secondly, to reduce the high implementation complexity encountered by the optimal PIC, we propose a low-complexity PIC by simplifying decision complexity and taking weight of the estimated multi-access interference for each interference cancellation (IC) stage. The performance of the low-complexity PIC over Rayleigh fading channel is analyzed and compared to the optimal PIC and conventional PIC, respectively. The simulation results show that the low-complexity PIC, whether IC weight coefficients are taken or not, shows a performance comparable to the optimal PIC and dominantly outperforms the conventional PIC. It is also shown that the low-complexity PIC with two IC stages is superior to the conventional PIC with three IC stages in performance, which is of practical value because PIC with fewer stages can bring shorter processing delay.