Average SNR of a generalized diversity selection combining scheme

The average signal-to-noise ratio (SNR) of a generalized selection combining scheme, in which the m diversity branches (m/spl les/L, where L is the total number of diversity branches available) with the largest instantaneous SNRs are selected and coherently combined, is derived. A Rayleigh fading channel is assumed, and a simple closed-form expression for the SNR is found which is upper bounded by the average SNR of maximal ratio combining, and lower bounded by average SNR of conventional selection combining.