The usage of multichannel receivers is a common feature in various practical realizations of wireless communication systems, caused by a need to combat the effects of various transmission drawbacks . With multichannel reception, it is usually assumed that the received signals are mutually independent. Nevertheless, in a number of practical realizations, this assumption cannot be taken for granted, due to insufficient antenna spacing at small-size mobile terminals (designed according to economical limitations and manufacturing restrictions). A well-known fact is that the correlation in fading across multiple diversity channels results in a degradation of the obtained diversity gain [2–4]. Generally, antenna separation in a distance of a few dozen wavelengths of carrier frequency is typically required to obtain low correlation between branches. Several correlation models have been proposed in the literature so far [2,3,5], and standard performance measures at the reception, considering various detection, modulation, and diversity combining scenarios, have been discussed.