History Based Adaptive Backoff (HBAB) IEEE 802.11 MAC Protocol

A mobile ad hoc network (MANET) is a collection of mobile nodes interconnected by wireless media. Several protocols have been proposed to manage multiple access to the shared wireless medium in MANETs, with the IEEE 802.11 being the most implemented protocol. In this work, a history-based adaptive backoff (HBAB) MAC protocol is proposed to provide a better QoS performance. HBAB modifies the original IEEE 802.11 binary exponential backoff (BEB) algorithm (which is used to control the contention window in the case of collisions) to reflect the network status and condition. Inspired by the adaptive delta modulation scheme that is used in communications, HBAB considers the history of past trials for transmission. Simulations show a significant improvement in performance measures (around 15% in packet delivery fraction and up to 50% in average packet delay) with using HBAB compared to the original backoff algorithm of IEEE 802.11.