General Exact Level Crossing Rates and Average Fade Durations of Dual Diversity Combiners over Non-Identical Correlated Ricean Channels

General exact expressions for the level crossing rate and average fade duration of dual-branch selection, equal-gain, and maximal-ratio combiners operating over non-identical correlated Ricean channels are derived. Sample numerical results are discussed by specializing the general expressions to a space-diversity system with horizontally spaced omnidirectional antennas at the mobile station. When the antennas are perpendicular to the direction of the vehicle motion, the average fade duration is loosely dependent on the antenna spacing and on the Ricean factor, being almost identical to that of the independent fading condition. When the antennas are parallel to the direction of the vehicle motion, the level crossing rate can be reduced below the value obtainable for independent fading signals. In this case, if a line-of-sight component exists, a further improvement in the average fade duration over the independent condition may be also achieved.