A Hybrid-Measure IEEE 802.11e Backoff Scheme in Wireless Mesh Sensor Networks

EDCA is a contention-based channel access scheme defined in the IEEE 802.11e standard and it can ensure quality of multimedia services. In this paper, we propose a new enhanced EDCA scheme called Hybrid-Measure EDCA(HM-EDCA), which dynamically adjust the important parameters-contention window(CW) size according to both of network condition and traffic state of traffic categories at each node. Network condition is measured by frozen rate during back off process, and queue length of each access category is used to estimate traffic state. Extensive simulations are performed to evaluate the proposed protocol. Simulation results demonstrate that HM-EDCA provides a good service differentiation, improves network throughput and reduce the package loss rate at heavy load conditions.