Mobile radio slotted ALOHA with capture, diversity and retransmission control in the presence of shadowing

In this paper, the capture performance of a random access scheme in the presence of Rayleigh fading, shadowing and diversity is studied. The conditional throughput C-n, i.e., the average number of packets which are correctly received per slot, given the number of colliding packets, n, is computed, as well as its limit as n --> infinity. Some different diversity schemes are compared. Also, retransmission control is considered as a means to enhance the system performance. The stability of the controlled system is directly proved. Finally, the effect of long-term attenuations on the system performance and stability is discussed.