Performance analysis and optimisation of a space-time selective PIC in CDMA wireless communication system

This paper deals with a parallel interference cancellation (PIC) detector for DS-CDMA wireless communication systems with adaptive antenna arrays. The proposed detector´s main feature lies in the utilization of PIC techniques for the adaptive antenna arrays receiver since optimum beamforming and one-shot interference cancellation are supposed to be used together. The proposed receiver is utilised at the end of up-link wireless DS/CDMA communication system in which BPSK modulation scheme is used in transmission so that asynchronous users and multipath fading phenomena are introduced. The proposed receiver basic assumption is to divide signals in reliable and unreliable ones after space-time combining. The reliable signals are directly detected and cancelled from each signal received by each sensor; afterwards processed signals are once again combined and detected in order to improve decision on unreliable signals. A suitable analytical approach is proposed in order to evaluate the error probability (P_e) and optimum threshold value of the receiver under consideration. Simulation results are also presented to validate obtained analytical predictions. It is shown here that proposed receiver shows a very good performance and, thanks to inherent low complexity of cancelling techniques, allows real-time operation. The performance is expressed in terms of the bit error rate (BER), which has been derived by simulations under the assumption of a frequency-selective Rayleigh fading channel