The Bit-Error-Rate Performance of Diversity Combining Techniques in Rayleigh Fading Channel

Diversity combining is a powerful technology for wireless networks. In this paper, types of diversity along with different diversity combining techniques ̶ Selection Combining, Maximal Ratio Combining and Equal Gain Combining are being discussed. An analytical expression for the signal-to-noise ratio (SNR) and bit-error-rate at the output of a three branch selection combining, maximal ratio combining, and equal gain combining is given. The diversity branches are assumed to be Rayleigh fading correlated with the BPSK modulation. Measurements of the signal-to-noise ratio and bit-error-rate after selection combining, maximal ratio combining, and equal gain combining were made in Rayleigh fading channels and compared with the analytical results. Comparisons of the performance of these combining techniques are made in terms of the complexity and improvement in SNR. An analytical result shows that the improvement in the case of equal gain combining is comparable to that of maximal ratio combining.