Superanalysis of the Interference Effect on Adaptive Antenna Systems

Abstract

We analyze the performance of optimum combining in a general cochannel interference environment with thermal noise. Specifically, we consider multiple unequal-power interferers, each is spatially correlated across receiving antennas. We develop a new mathematical methodology to analyze the average symbol error probability (SEP) of optimum combining diversity systems in Rayleigh fading. The analysis resorts to the so-called Berezin's supermathematics that treats both commuting and Grassmann anticommuting variables on an equal footing. This superanalysis framework enables us to derive the exact SEP expression for an arbitrary number of interferers with spatial correlation and possibly different power levels. Our results therefore encompass all the previous analytical results, based on the theory of multivariate statistics relating to complex Wishart matrices, for equal-power and/or spatially-uncorrelated interferers. Connecting the powerful supermathematical framework to the analysis of wireless diversity systems with optimum combining, we quantify the interference effects in terms of the degree of power unbalance and the amount of spatial correlation.