RWBOA(Pd,w): Novel Backoff Algorithm for IEEE 802.11 DCF

The Probability Distribution of Slot Selection (PDoSS) of IEEE 802.11 DCF is extremely uneven, which makes the packet collision probability very high. In this paper, the authors explore how to make the stations select the slots uniformly, and give an RWBO(Pd, w) algorithm for 802.11 DCF to make the PDoSS even and decrease the packet collision probability. A Markov model is given to analyze the PDoSS of RWBO(Pd, w). The performance of RWBO(Pd, w) is evaluated by simulation in terms of saturation throughput and packet collision probability. The simulation results indicate that RWBO(Pd, w) can decrease the packet contention probability to a large extent, and utilize the channel more efficiently as compared to the 802.11 DCF. Moreover, the relation between saturation throughput and walking probability (Pd, w), the relation between saturation throughput and contention windows (w), the relation between packet collision probability and walking probability (Pd, w), and the relation between packet collision probability and contention windows (w) are analyzed. The analysis indicates that RWBO(Pd, w) has some remarkable features: its saturation throughout keeps high and packet collision probability keeps very low (under 0.1) in a large range of Pd and w, which allow users to configure Pd and w more flexibly.