Self-selection route discovery strategies for reactive routing in ad hoc networks

Routing in Ad hoc Networks has received a significant amount of attention. In recent years, the focus of research has been in on-demand (or reactive) routing protocols due to the recognition that these protocols have the potential to achieve higher levels of scalability than proactive routing strategies. However, most on-demand routing protocols proposed to date attempt to increase routing efficiency by using existing knowledge about the destination or by increasing the stability of the routes. Little research has been done to reduce route discovery overhead when no previous destination information is available. We present a number of different strategies, which encourage a more distributed and localised approach to route discovery by allowing each intermediate node during route discovery to make forwarding decisions using localised knowledge and self-selection. The use of self-selection for route discovery enables nodes to independently make route request (RREQ) forwarding decisions based upon a selection criterion or by satisfying certain conditions. The nodes which do not satisfy the selection criterion do not rebroadcast the RREQs. This provides a more effective and efficient search strategy than the use of traditional brute force blind flooding. We implemented our self-selecting route discovery strategies over AODV using the GloMoSim network simulation package, and compared the performance with existing routing protocols. Our simulation results show that a significant drop in the number of control packets can be achieved by giving each intermediate node more authority for self-selection during route discovery. Furthermore, a significant increase in routing performance is achieved as the number of nodes in the network is increased.