Mathematical and Simulation Analysis of Contention Control Algorithm for Saturated Wireless Networks

An efficient Contention Control algorithm aims to resolve contention among stations in a dynamic wireless environment. It seeks to achieve maximum throughput and low packet delay in transmission by maintaining fairness among active stations. The IEEE802.11 Binary exponential backoff algorithm (BEB) and most of the existing related algorithms never consider the current network load and hence provide unfair channel access. To mitigate these problems, an adaptive contention and congestion control (CCC) algorithm is proposed to estimate an appropriate contention window (CW) adjustments. The proposed CCC algorithm has two different mechanisms namely ConTention control and ConGestion control to effectively distinguish contention from congestion. But, BEB and most of the existing algorithms have failed to make such differentiation thereby increasing delay and collisions in saturated wireless network. The proposed CCC algorithm dynamically modifies both the lower and upper bounds of CW with respect to contention level and collision rate. An analytical model and extensive simulation study facilitate to highlight the performance enhancements of the proposed CCC algorithm in linear and random topologies. The simulation results reveal that the proposed algorithm outperforms the existing algorithms in terms of packet delivery ratio, packet loss, end-to-end delay, overheads and collision rate.