Capture and diversity in Ricean-faded mobile radio channels

In this paper the capture probabilities, C_n, defined as the probability that any of n contending packets is correctly received, are found, with reference to a random access mobile radio communications system in the presence of fading, shadowing, and near/far effect. A Ricean model for fading, which is more general than the well-studied Rayleigh fading, is then considered. The capture probabilities are computed and their dependence on the system parameters, and in particular on the Rice factor, K, is investigated. The use of antenna diversity to combat fading is also considered. As an example of application, a slotted ALOHA system is considered and the performance of a simple control strategy is studied. Also some analytical results are given as to the value of C_∞=lim_n→∞C_n, which is relevant to the study of the system stability