Novel Simpler Expressions for the BER of MRC BPSK in Correlated Rayleigh Fading and CCI

Exact closed-form expressions are derived for the bit error rate of binary phase shift keying in Rayleigh fading channels with maximal ratio combining diversity in the presence of cochannel interference and additive white Gaussian noise. The desired signal and the interferer signals are subject to correlated Rayleigh fading and binary phase shift keying modulation is used by all users. Using the derived expressions, it is shown through some numerical examples that for a fixed number of antennas, there is a best radius for a uniform circular array at which the array performance is almost as if all antennas in the array were uncorrelated. Counterintuitively, at this radius, the adjacent antennas in the array are not uncorrelated.