SYMBOL ERROR PROBABILITY PERFORMANCE FOR GENERALIZED SELECTION COMBINING DIVERSITY RECEPTION OF M-QAM OVER RAYLEIGH FADING CHANNEL

Abstract

The performance of generalized selection combining (GSC) diversity reception symbol error probability (SEP) of square M-ary quadrature amplitude modulation (M-QAM) signals over frequency-flat Rayleigh fading channels is investigated in this work. The combining techniques considered in this paper are maximum ratio combining and selection combining (SC). We present closed-form approximate expressions for the average combined signal-to-noise ratio (SNR) and SEP in the fading channel for M-QAM signal reception in the GSC using diversity pathways that are independently, identically distributed. The simulation results validate the SEP expressions and demonstrate that, for a given number of accessible diversity paths, combining the strongest paths results in the majority of the diversity gain, and that the SNR declines as the number of combined paths increases. On the other hand, the numerical results demonstrate that, for a certain number of combined paths, increasing the number of available diversity paths can lead to a significant performance improvement.