RANDOM MULTIPLE ACCESS COMMUNICATIONS ON MULTIPACKET RECEPTION CHANNELS

By applying multiuser detection techniques, receivers today can decode mul-tiple packets transmitted simultaneously over a channel. Known as multipacket reception (MPR), this presents a physical layer model significantly different from the one that practical design and theoretical analysis of many network protocols have traditionally assumed. The principal objective of this study is to consider the design of efficient multiple access communication systems for this new model. Specifically, we investigate the maximum stable throughput attainable with decentralized control using channel sense multiple access (CSMA), which has not previously been studied with MPR. We show CSMA provides throughput gain over slotted ALOHA (S-ALOHA), the non-channel-sensing protocol of choice. However, we also find that this gain diminishes as the physical layer strength increases, thereby diminishing the need for channel sensing. Searching for improvements, we investigate the generalized CSMA protocols which allow new transmissions to begin even when the channel is already in use, provided the usage level is below capacity. In addition, we also analyze the effect