RDMAR: a bandwidth-efficient routing protocol for mobile ad hoc networks

We present a loop-free routing protocol for ad hoc mobile networks. The protocol is highly adaptive, efficient and scaleable; and is well-suited in large mobile networks whose rate of topological changes is moderate. A key concept in its design is that protocol reaction to link failures is typically localised to a very small region of the network near the change. This desirable behaviour is achieved through the use of a novel mechanism for route discovery, called Relative Distance Micro-discovery (RDM). The concept behind RDM is that a query flood can be localised by knowing the relative distance (RD) between two terminals. To accomplish this, every time a route search between the two terminals is triggered, an iterative algorithm calculates an estimate of their RD, given an average nodal mobility and information about the elapsed time since they last communicated and their previous RD. Based on the newly calculated RD, the query flood is then localised to a limited region of the network centred at the source node of the route discovery and with maximum propagation radius that equals to the estimated relative distance. This ability to localise query flooding into a limited area of the network serves to minimise routing overhead and overall network congestion. Simulation results illustrate its performance and demonstrate its good behaviour comparing to other protocols proposed by IETF Working Group. We refer to the protocol as the Relative Distance Micro-discovery Ad Hoc Routing (RDMAR) protocol.