Statistical analysis of multiple access interference in Rayleigh fading environment for MIMO CDMA systems

A major limiting factor in the performance of MIMO-CDMA systems is multiple access interference (MAI) which can reduce the system capacity as well as bit error rate (BER). Thus, statistical characterization of MAI is vital in analyzing the performance of such systems. Since, the statistical analysis of MAI in MIMO-CDMA is quite involved especially in the presence of fading channels, existing works in literature employ suboptimal approaches to detect the subscriber without involving the need for MAI statistics such as successive interference cancellation (SIC) and parallel interference cancellation (PIC). To date, the exact characterization of multiple access interference in MIMO-CDMA is an unsolved problem. In this paper, we derive the expressions for the probability density function of MAI and MAI plus noise in MIMO-CDMA systems in the presence of both Rayleigh fading channels and additive Gaussian noise. Simulation results show that the theoretical predictions are very well substantiated.