Throughput-delay performance of packet-switching multiple-access channel with power capture

Abstract Power capture is the ability of a receiver to receive correctly the strongest of several messages that arrive during overlapping intervals. The presence of power capture in multiple-access packet switching channels introduces inequality in the access conditions to the channel when packets arrive at the receiver at different power levels. Two models for such channels under slotted ALOHA protocol with power capture are considered. In the first, a packet is transmitted at one of K possible power levels, and it is received correctly if no other packet is transmitted at the same or higher level. The second model is of a ground radio network where a received packet's power is inversely proportional to the distance it propagates. In this model, a packet transmitted from a distance r is received correctly if no other packet is transmitted from a distance smaller than a · r (a ⩾ 1). A technique developed by Lam (1974) is generalized to obtain the throughput-delay characteristics of the channel for both models. The effect of high power traffic on the lower power traffic is discussed, and it is shown that the ‘Sisyphus distance’ phenomenon predicted by Abramson (1977) for the case a = 1 in the second model does not exist in the more realistic case of a > 1.