Postdetection selection diversity with unequal branch signal power compensation

A new postdetection two-branch selection diversity scheme is proposed that can reduce the influence of unequal average signal powers of the two branches. A BER analysis is presented for pi /4-shift QDPSK assuming very slow Rayleigh fading channel. It is shown that if the difference in average powers is 6 dB, the BER performance due to cochannel interference can be improved by about 1.3 dB and is almost identical to that of the equal average power case.