Hashing Based Distributed Backoff (HBDB) Mechanism for IEEE 802.11 Wireless Networks

Binary Exponential Backoff (BEB) is the De-facto mechanism for contention control in IEEE 802.11 Wireless LAN. The exponential growth of Contention Window (CW) in all BackOff (BO) stages and randomness in BO selection causes unnecessary waiting time, high collision rate and unfairness in accessing the channel among the nodes. To overcome these anomalies, this paper proposes Hashing Based Distributed Backoff (HBDB) algorithm. It allows a node to dynamically adopt different CW values based on the collision probability. To choose unique collision probability value, linear probing is used. The simulation results show the effectiveness of the proposed algorithm in linear and random topologies under low, medium and high traffic scenarios.