BER Performance of Local Average Gain Combining with BPSK in Rayleigh Fading Channels

We propose a novel diversity combining method called local average gain combining (LAGC) that is based on the local average of channel gains. Compared with MRC, which requires the instantaneous complex channel coefficients, and EGC, which requires only the instantaneous channel phases, LAGC requires the instantaneous channel phases but the lo- cal average of the channel gains, implying an implementation complexity between those of MRC and EGC. The average bit error probability (ABEP) of LAGC is analyzed and derived in closed-form using a method that is based on the characteristic function (cf) and the Paserval´s theorem, showing that LAGC approximates to MRC in slow fading and to EGC in balanced fast fading. Simulations are performed to validate the analysis. The channel phase estimation error is included in the simulation, and it turns out that LAGC and EGC significantly outperform MRC and SC. This is a distinct advantage of LAGC because in fast fading it is more difficult to track the channel coefficients and on average the channel phase error is larger.