Exact SEP of optimum combining in the presence of noise and rician-faded interferers

In this paper, we investigate the performance of optimum combining multiple antenna systems in the presence of Rician-faded interferers. We assume that the desired user is subjected to Rayleigh fading but interferers undergo Rician fading. Unlike other approaches addressing optimum combining with Rician fading, we consider the effect of both interference and thermal noise. Our methodology is based on the evaluation of the moment generating function of the signal-to-interference-plus-noise (SINR) ratio at the output of the combiner. Our results are exact, and allow the calculation of the symbol error probability (SEP) for M-PSK signals with arbitrary number of antennas and interferers