Statistical performance analysis of optimum combining with co-channel interferers and flat Rayleigh fading

In this paper, we examine the statistical distribution of the signal to interference plus noise ratio (SINR) of the optimum combining (OC) technique in receive antenna diversity systems. The channel is modelled as flat Rayleigh fading, slowly varying and spatially independent. When the number of interferers is less than the number of antennas, our approach considers unequal power interferers and decomposes the SINR into sum of two independent terms by projection onto interference and noise orthogonal subspaces. Following the decomposition, the distributions for these projections are sought. For the case when the number of interferers is larger, approximations to the distribution are provided along with performance upper and lower bounds.