Optimal error analysis of receive diversity schemes on arbitrarily correlated Rayleigh fading channels

A simple optimal error analysis of multiple-branch equal gain combining (EGC) and selection combining (SC) in the presence of arbitrarily correlated Rayleigh fading channels is presented. It is shown that the error rates over correlated branches for diversity combining schemes can be analysed at the output of an eigenfilter splitter, which is placed at the output of the diversity combiner. Since the outputs of the splitter are uncorrelated, the error analysis of maximal ratio combining (MRC) technique is applied to EGC and SC. This analysis is possible since error performance of MRC with correlated branches is optimal and invariant to eigenfilter or eigenvector decorrelation and the decorrelated outputs can simply be analysed similar to independent branches. The authors exploit extensive simulations for average bit error probability, which show tight bounds with the proposed analytical approach. Channel correlations for different practical antenna spacing of 0.15, 0.2 and 0.5 of the signal carrier wavelength, λ are analysed.