Level Crossing Rates of an Equal-Gain Predetection Diversity Combiner

An
M
branch equal-gain predetection space-diversity combiner is analyzed for the case where the signals received from the individual branches of such a combiner are partially correlated. The level crossing rate (LCR) of the combined signal envelope equals the probability density function times a function of the direction of motion. When a linear antenna array is used on a mobile radio receiver, the direction of motion does not affect the shape of the LCR curve of the combined signal but does affect the absolute values, especially when the antenna spacing
d
is less than 0.5 λ. There is apparently no effect for
d > 1 \lambda