Distributed Optimal Contention Window Control for Elastic Traffic in Wireless LANs

This paper presents a distributed contention window control control algorithm, GCA (General Contention window Adaptation), that achieves various bandwidth allocation policies and at same time efficient channel utilization. By modeling different bandwidth allocation policies as optimization problems of contention window assignment, we are able to design GCA and prove that it converges to the solution of the contention window assignment problem. By examining the stability properties of GCA, we identify the optimal stable point that maximizes channel utilization and provide solutions to control the stable point of GCA near the optimal point. Simulation results show that GCA achieves fairness and efficiency. Due to the generality of GCA, our work provides a theoretical foundation to analyze existing and design new contention window control algorithms