Enhancement of DSR and AODV Protocols Using Link Availability Prediction

Routing in wireless ad hoc networks is highly affected by its dynamic topology and power constrained mobile devices. Several routing protocols like proactive, reactive, hybrid, geographical, etc. have been proposed in the literature. Ineffectiveness of any routing protocol in such networks is caused due to the ignorance of link availability during the routing phase. In this paper, we proposed two link availability prediction techniques which are performed during routing of control packets. The first technique referred as zone based estimation, divides the transmission range area of every node into three zones namely inner, middle and outer, based on the received signal strength. Here, nodes lying in the inner and outer zone are prohibited from the control packet transmission as they have extremely high and low received signal strength, respectively. Nodes in the middle region are only allowed for the control packet flow within the locality. The second technique is an improvement over zone based estimation, where nodes in the outer zone are considered for route selection and is referred as segment based estimation. It calculates node's link availability ratio for each adjacent links based on the current available position of the neighbor, its adjoining segment and sector where the neighbor is present within the transmission region of the node. This information assist in the control packet transfer within the outer zone. Simulation has been performed over DSR and AODV protocols in terms of control overhead bandwidth, number of control packets, route length and number of route errors generated in the network. The results show that the knowledge of link status during routing phase helps to find more stable routes with reduced control overhead and hence increases the overall network performance.