Level Crossing Rate and Average Fade Duration of EGC Systems with Cochannel Interference in Rayleigh Fading

摘要

Both the first-order signal statistics (e.g. the outage probability) and thesecond-order signal statistics (e.g. the average level crossing rate, LCR, andthe average fade duration, AFD) are important design criteria and performancemeasures for the wireless communication systems, including the equal gaincombining (EGC) systems in presence of the cochannel interference (CCI).Although the analytical expressions for the outage probability of the coherentEGC systems exposed to CCI and various fading channels are already known, therespective ones for the average LCR and the AFD are not available in theliterature. This paper presents such analytical expressions for the Rayleighfading channel, which are obtained by utilizing a novel analytical approachthat does not require the explicit expression for the joint PDF of theinstantaneous output signal-to-interference ratio (SIR) and its timederivative. Applying the characteristic function method and the Beaulieuseries, we determined the average LCR and the AFD at the output of aninterference-limited EGC system with an arbitrary diversity order and anarbitrary number of cochannel interferers in forms of an infinite integral andan infinite series. For the dual diversity case, the respective expressions arederived in closed forms in terms of the gamma and the beta functions.