Simulation of adaptive statistically multiplexed routing in ad hoc networks

? This paper develops a solution to the problems of discovery, maintenance, and use of multiple routes in ad hoc networks. Performance criterion is the average time taken by a packet to reach its destination through multiple hops. A source node considers each of its neighbors (reachable by direct wireless transmission) as a gateway for every possible destination. The eeect of delay at a gateway and beyond, until the packet reaches its destination , is approximately modeled as an M/M/1 queuing system. Potential gateways at every node provide multiple routes. Multiple routes are statistically multiplexed to distribute the load as well as to deal with changes in data and network conng-uration. The potential of each gateway of a node is estimated on-line and the proportions of traac routed through multiple gateways are also updated adaptively. Simulation results are presented and discussed. Nomadic computing encompasses a wide variety of computing and communication scenarios wherein the hosts are mobile, may function intermittently, and the network organization itself is ad hoc, somewhat ineecient, but caters to the need of possibly a temporary application in environments with very little control. Numerous potential applications of such networks are cited in Kleinrock 1]. Research interest in modeling and development of solution algorithms for various functions of such networks is rapidly growing. The main problem addressed in this paper is the distributed construction and maintenance of multiple routes. Although attention is on ad hoc networks, some of the techniques, especially statistical multiplexing are applicable to other network types also. Johnson 2] suggests separate route discovery and maintenance protocols for routing in ad hoc networks. Haas and Pearlman (see 3]) propose the \Zone Routing Protocol" for large at-routed wireless networks, wherein updates are propagated only locally. Details are omitted here due to page limitation. In this paper, we concentrate on adaptive algorithms for maintaining and updating multiple routes in changing network conngurations, in ad hoc networks. Examples of changes in conngurations include a node being congested or otherwise not being able to serve as a relay station for some time intervals. We rst develop a common problem for load balancing and maintenance of eecient multiple routes between source-destination pairs. The statistical model of traac, switching, and performance are approximate to ensure simplicity. Deviations from our model are expected to be reeected as corresponding variations from the ideal without causing instability, operational problems, or func-tionality. Our next idea is …