The Impact of Noise on Switching Rate of L-Fold Selection Diversity

Switching transients generated by a selection diversity combiner corrupt receiver filters and increase the system outage as well as corrupting channel estimation. In order to produce an accurate (transient-free) channel estimate and reduce the internal outage, one prefers small switching rates. Therefore, knowledge of the switching rate provides useful information for system engineers in the design of selection diversity receivers. Yet, few results regarding the switching rates of select diversity receivers operating in noisy fading channels have been published. The switching rate of L-fold selection diversity combining in a noisy environment is studied. A closed-form expression for the switching rate is derived for independent and identically distributed (i.i.d.) Rayleigh fading channels in the presence of noise using order statistics. Simulation results are also provided to validate the theoretical results. Our results show that in order to produce an accurate channel estimate and reduce the internal outage, one prefers small switching rates, which can be realized by employing adaptive receiver filters to avoid excessive deleterious switching transients.