Local Repair Mechanisms for On-Demand Routing in Mobile Ad hoc Networks

With the dynamic and mobile nature of ad hoc wireless
networks, links may fail due to topological changes by
mobile nodes. As the degree of mobility increases, the wireless
network would suffer more link errors. Ad hoc routing
protocols that use broadcast to discover routes may become
inefficient due to frequent failures of intermediate
connections in an end-to-end communication. When an intermediate
link breaks, it is beneficial to discover a new
route locally without resorting to an end-to-end route discovery.
Based on the concept of localizing the route
request query, we propose an efficient approach to repair
error links quickly. The approach can apply to the
Ad hoc On-demand Distance Vector (AODV) routing protocol.
As an enhancement to AODV, the proposed approach
leads to two routing protocols, called AODV-LRQ
and AODV-LRT, which are aimed to efficiently repair
the link errors. To evaluate the effects of the route repair,
we define a factor, called bonus gain, as the ratio
between the throughput increment to the routing overhead
increment. Simulation results show that the proposed
methods can get high bonus gain, that is, it can maintain
the throughput as well as reduce the routing overheads.