Enhancing the Performance of Geographical Routing Protocol in Highly Dynamic Mobility and Mobility Patterns

Abstract

In geographical routing, each node takes the data forwarding decision based on the location information of its one-hop neighbors. Dissemination of location information is the key function of the geographic routing. The location error due to the node mobility models has direct impact on the geographical routing. Node mobility is a great challenge to the beacon based location broadcasting schemes. The general mechanism to optimize the local topology information according to the node mobility is Proactive beaconing schemes support specific mobility model, but it does not perform well under various mobility models. However, it is difficult to capture the changes in the network topology and fit the beaconing approach correctly to the various mobility models. This paper proposes the Context Aware Mobility Adaptive Location Update (CAALU) scheme which contains Distance and Traffic based Location update (DTL), Band Prediction (BP), and Conditional Location Update on Overhearing (CLUO). These schemes make CAALU more flexible to various mobility models. For supporting the mobility models, the DTL dynamically adjusts the beaconing interval based on the node distance and traffic. For simplification, it divides the node transmission area into inband and out-band region, and each node continuously exchange its location information with the out-band nodes. The BP mechanism predicts the mobile node region and broadcast the beacon only if the predicted distance error is greater than the threshold range. The CLUO mechanism employs the MAC layer overhearing concept whereby a node sends the beacon packet, when it overhears the data/beacon packet transmission from a new neighbor. Simulated results reveal the adaptability of CAALU on various mobility models.