Performance analysis of generalized selection combining with threshold test per branch (T-GSC)

We analyze the average bit error rate (BER) and outage probability performance of two types of conditional diversity combining schemes in which each branch signal-to-noise ratio (SNR) is tested against a fixed predetermined threshold and applied to the combiner only if its value exceeds this threshold. The two schemes, respectively referred to as absolute threshold generalized selection combining (AT-GSC) and normalized threshold generalized selection combining (NT-GSC), differ from one another only in the manner in which the threshold is chosen. Nevertheless, when operating over a generalized fading channel, the two schemes have a markedly different behavior as reflected in the numerical results presented. The analytical method taken to obtain these results follows the moment generating function approach originally proposed by the authors for analyzing the performance of more conventional diversity combining schemes (see Simon, M.K. and Alouini, M.-S., Proc. IEEE, vol.86, p.1860-77, 1998).