In this paper, the macro-diversity system consisting of macro-diversity (MAD) selection combining (SC) receiver and two microdiversity (MID) SC receivers, is considered. This MAD system alleviates the impact of short term fading, long term fading and co-channel interference. The desired signal suffers Rayleigh short term fading and correlated Gamma long term fading. Cochannel interference is affected by Nakagami-m short term fading and independent Gamma long term fading. The expression for the level crossing rate (LCR) of MAD system under such conditions is derived in closed form and presented graphically. The influence of Gamma long term fading severity parameter, Gamma long term fading correlation coefficient and Nakagami-m short term fading severity parameter on the LCR are analyzed and discussed. This work is of great importance in the design of wireless communication systems in the presence of combined effect of fading and interference. Also, the LCR is important systems’ performance because, for example, the LCR influences the error correction codes performance.

Keywords: Gamma large scale fading, Rayleigh fading, Nakagami-m co-channel interference, Level crossing rate, Selection combining (SC)