Random access for multiple destinations with physical layer considerations

Most studies of wireless random-access systems have addressed single-destination networks (e.g., an isolated base station in a cellular network). Here, we consider networks with many users and multiple destinations, where omnidirectional antennas are used for communication over a common channel, and transmissions intended for one destination can interfere with those intended for others. Our previous work on such networks assumed a simplified model for the physical layer, under which communication and interference ranges were characterized by fixed values and capture was not possible. In this paper, we use a more-realistic threshold model for the physical layer, under which a packet is successfully received if its received signal strength is sufficiently greater than the combined power of all other packets transmitted in the same slot. We use simulation to evaluate the maximum throughput that can be achieved by Slotted Aloha for multiple-destination networks. Throughput performance results demonstrate the impact of the degree of overlap of these clusters, as well as the impact of capture