New generalized selection combining for BPSK signals in Rayleigh fading channels

We propose a new generalized selection combining (GSC) scheme that selects m diversity branches out of L (≥ m) diversity branches based on the magnitude of log-likelihood ratio (LLR), which, for BPSK signals, is proportional to the product of the fading amplitude and the matched filter output. The proposed GSC is shown to provide a significant power gain over the conventional GSC which selects diversity branches based on signal-to-noise ratio. The proposed GSC scheme for m = 3 is found to be only 0.3 dB inferior to the maximal ratio combining scheme (m = L), when L = 8, in a Rayleigh fading channel.