optimized backoff algorithm based on priority and mobility for collision avoidance in wireless ad hoc networks

Abstract

A Wireless ad hoc network (WANET) is a collection of heterogeneous network node newlineforming the temporary networks without the aid of any infrastructure or any centralized newlineadministrator. Collision avoidance is done in such a way that when the channel is idle, newlinethe node waits for a randomly selected duration before trying to send. The Backoff newline(BO) algorithm is a part of MAC protocol which is used to avoid collision in ad hoc newlinenetwork. newlineDesigning of a backoff algorithm is crucial to improve the performance of nodes in newlinewireless ad hoc and networks. Most of the existing algorithms have modified the newlineBinary Exponential Backoff (BEB) algorithm to provide relative priority among newlinemultiple traffic classes. However, the method of decrementing the CW was not newlineaddressed and assumed to remain the same as the original BEB algorithm. Hence, a newlinepriority based optimized backoff (PBOB) algorithm for collision avoidance has been newlineproposed for static nodes scenario in WANET. In PBOB, the contending nodes are newlineprioritized based on their residual energy, load and traffic type. Then during contention newlineperiod, the backoff interval is adaptively adjusted based on the priority of each newlinecontending node. newlineConsideration of mobility in ad hoc wireless networks introduces new challenges for newlinethe design of MAC protocols. But most of the MAC protocols proposed for ad hoc newlinenetworks assume static nodes scenario, which usually provide very bad network newlineperformance in case of mobile nodes. Hence, Cross-layer based Mobility-aware newlineBackoff Algorithm (CBMA) for collision avoidance algorithm is proposed for mobile newlinenodes scenario. In this algorithm, based on the estimated relative mobility and newlineiv newlineresidence time, nodes are categorized into 3 levels. Then the back off interval is newlineadjusted based on the determined level of the nodes. newlineFinally, Optimized Adaptive Backoff Algorithm (OABA) is proposed for static and newlinemobile wireless ad hoc networks. In this algorithm, during the back off stage, the type newlineof node is determined as static or mobile. For mobile nodes, their residence