Comparing slotted and continuous CSMA: throughputs and fairness

摘要

Carrier-Sense Multiple-Access (CSMA) protocols form a popular class of random-access schemes for regulating node activity in wireless networks. We compare the continuous and the time-slotted versions of this protocol in the saturated regime, and show that continuous CSMA has higher aggregate throughput than the slotted protocol, but this comes at the cost of fairness, i.e., the throughput is not evenly distributed across all nodes. We then release the saturation assumption and consider a multi-hop scenario where packets are forwarded through the network and nodes may occasionally empty. We study end-to-end throughput of both continuous and slotted CSMA, and show that slotted CSMA has a higher throughput than the continuous protocol.