Preemptive Routing Algorithm in Ad Hoc Networks

Mobility of the nodes in wireless ad hoc networks causes routes to break frequently, which results in significant performance degradation of networks. An extension to ondemand ad hoc routing protocols called Preemptive Routing Algorithm is proposed in this paper. Link State Analysis is the essential part of the algorithm. The preemptive algorithm tries to ensure the reliability of the new discovered route during the route discovery. When the received signal power is below the dangerous threshold, Link State Analysis module is initiated to predict the broken time of the link. A preemptive route maintenance action is taken in advance if the predicted broken time is less than response time. The simulation result shows that Preemptive Routing Algorithm proposed in this paper significantly reduces the number of broken paths, decreases the packet delivery delay and improves the performance of networks with a small increase of protocol overhead.