An Improvement of Ad Hoc Route Maintenance

Ad Hoc wireless network consists of mobile nodes that do not rely on any fixed network infrastructure. The dynamic route is allocated for a pair of nodes by Ad Hoc on-demand routing protocol (AODV), that establishes a route only when a source node want to transmit data. Routes in Ad Hoc network can be broken caused by a node in the route may move out of their neighbor´s signal range or node´s battery may be ran out. Many algorithms have been developed to solve the problem [1],[6], one of them is break avoidance algorithm (AODV-BA [1]). However, using AODV-BA protocol, an upstream node of the broken link has to buffer packets during the route maintenance process. In case that the route maintenance is unsuccessful, the source node must re-establish a new route. In this paper, we propose AODV Backup Route Discovery with 2 Levels of Threshold (AODV-2T). The protocol tests for the power of its own battery power and its neighbors´ RF signal. And it would cooperate with the neighbors to find a backup route as to fix the weak link problem where the first threshold is met. Consequently, if the power of signal or battery is fallen below the second threshold level, AODV-2T node could switch the data packet transmission to the new route without any delay. AODV-2T can reduce connection tear-off that causes packets lost and more routing control overhead by 15-18 percent compared to the original AODV and AODV-BA.