An improved backoff algorithm with node access fairness in WLAN

Distributed coordination function (DCF) is the most widely deployed medium access control (MAC) protocol for IEEE 802.11 Wireless Local Area Networks (WLANs). The carrier sense multiple access with collision avoidance (CSMA/CA) scheme which employs a binary exponential backoff (BEB) algorithm is used to reduce the collision probability. In this paper, we propose an improved collision backoff algorithm considering the node access fairness. In NAFB, different stations, including sending stations and non-sending stations, adopt different contention window adjustment strategies according to the sensed collision situations. Simulation results showed that the proposed algorithm not only ensures the fairness of node access in the network, but also improves the performance in terms of the network throughput, packet loss rate and average packet delay to some extent.