Medium Access Control with Physical Layer Assisted Loss Differentiation

The binary exponential backoff (BEB) algorithm used in IEEE 802.11 DCF suffers from the unfairness problem and yields low throughput under heavy load. With physical layer assisted loss differentiation, this paper proposes a new distributed queuing medium access control (MAC) protocol (PALD-DQMP). In this protocol, utilizing the user detection module in the physical layer, losses due to collisions are distinguished from those due to link errors, and such information is made available to the MAC layer. Based on different users' channel states, PALD-DQMP schedules their transmissions. Simulation results show that the proposed scheme outperforms the standard MAC protocol in terms of network throughput and fairness. This improvement is mainly due to the availability of cross-layer channel information, and the elimination of collisions and backoff periods.