An Intelligent Contention Window Control Scheme for Distributed Medium Access

This paper proposes a novel contention window control scheme for backoff based CRA (Collision Resolution Algorithm). The proposed scheme demonstrates a distributed way to control random slot selection over the contention window in each contention stage with reference to normalized backoff value in the previous contention stage. Such control results an intelligent backoff time distribution over the contention window for each contention stage. Backoff time chosen for every access from such distribution potentially mitigates much collisions along with reduced channel ideal time. Analysis results show that, compared to the performance of legacy scheme incorporating DSSS (Direct Sequence Spread Spectrum) 802.11b system parameters, there is at least 13% normalized throughput enhancement with heavily reduced packet delay in an IBSS (Independent Basic Service Set) with more than 30 stations with saturated traffic.