Collision mitigating sliding DCF backoff algorithm (SDBA) for multi-hop wireless networks

Abstract

In the IEEE 802.11 based wireless networks, an adjustment of the Contention Window (CW) is indispensable in order to provide a differentiated quality of service. Distributed Coordination Function (DCF) is a contention-based MAC method which allows to mutually share the common wireless channel. DCF backoff algorithm regulates the size of CW range upon successful transmissions and collisions. Due to wireless medium characteristics and node mobility, estimating pertinent CW range is a very crucial task. This paper proposes Sliding DCF Backoff Algorithm (SDBA) that predicts current medium status using Backoff Success Ratio (BSR). According to this, SDBA slides both CW lower and upper boundaries. To investigate the behavior and capability of the proposed SDBA, extensive NS2 simulations are carried out with varying mobility speed under random topology. It is perceived from the simulation results that the proposed algorithm attains better throughput and significantly reduces collisions, routing control overhead and energy consumption, thereby extending network lifetime.