General Exact Level Crossing Rate and Average Fade Duration for Dual-Diversity Combining of Nonidentical

This paper derives general exact expressions for the level crossing rate (LCR) and the average fade duration (AFD) of dual-branch selection, equal-gain, and maximal-ratio combiners operating over non- identical correlated Weibull fading channels. Sample numerical results are discussed by specializing the general expressions to a space-diversity system using horizontally spaced antennas at a mobile station. It is verified that as the antenna spacing becomes larger, the LCR decreases, becoming oscillatory and convergent. In addition, when the direction of the mobile is perpendicular to the axis of the antenna, the AFD is loosely dependent on the antenna spacing. Some simulation results are presented to verify the correctness of the analytical formulation. Index Terms—Average fade duration (AFD), diversity-combining techniques, level crossing rate (LCR), Weibull fading channels.