Ad Hoc Networks: GPS-Based Routing Algorithm

Abstract

This entry presents a routing algorithm, which receives the location and mobility information from GPS. number of hops among available routes. However, the route having the minimum number of hops is not always the best routing path. Although the route having the minimum number of hops may be faster than other routes in packet delivery, it may be highly probable that the spatial distance between any two intermediate nodes in the route may be larger than those in other routes. The larger distance between neighboring nodes may give rise to shorter link maintenance time, which in turn shortens the route maintenance time. If there are frequent route failures due to host mobility, it will require additional time to reconfigure the route from the source to destination, which results in increased amounts of control packet flooding. Therefore, it may not be said that a route with the smallest hop count is necessarily optimal. The goal of our work is to select the most reliable route that is impervious to link failures by topological changes by host mobility, where a route discovery is performed with the location and mobility information received by GPS. To accomplish this goal, we propose new route discovery algorithms referred to as reliable route selection (RRS). In this entry, we assume that each node is aware of its current location through the use of GPS receivers with which each node is equipped. GPS has been successfully employed for determining a mobile node’s position and speed. It is expected that the proliferation of GPSbased positioning technology will proceed at a fast pace, and the accuracy of this technology will be dramatically enhanced. The remainder of this entry is organized as follows. Section “Ad Hoc Routing Protocols” briefly describes related works—DSR and AODV routing protocols. Section “GPS” provides some background on GPS. Section “RRS Algorithms” describes the proposed GPS-based RRS algorithms. The performance of the proposed algorithms is evaluated and compared in section “Performance Evaluation.” We summarize our results in the last entry. IntroductIon Mobile multi-hop wireless networks, called ad hoc networks, are networks with no fixed infrastructure, such as underground cabling or base stations, where mobile nodes are connected dynamically in an arbitrary manner. Thus, nodes in such networks function as routers, which discover and maintain routes to other nodes. A central challenge in the design of ad hoc networks is the development of dynamic routing protocols that can efficiently find routes between the source and destination. The routing protocols must be able to keep up with the high degree of node mobility, which often changes the network topology drastically and unpredictably. Routing protocols in conventional wired networks generally use either distance vector or link state routing protocols, both of which require periodic routing advertisements to be broadcast by each router. However, such protocols do not perform well in dynamically changing ad hoc network environments. The limitations of mobile networks, such as limited bandwidth, constrained power, and host mobility, make designing ad hoc routing protocols particularly challenging. To overcome these limitations, several source-initiated on-demand routing protocols, including dynamic source routing (DSR) and ad hoc on-demand distance vector (AODV), have been proposed. These protocols create routes only when the source node has data to transmit. When a node requires a route to a destination, it initiates a route discovery procedure. This procedure is completed once a route has been found or all possible route permutations have been examined. Once a route has been established, it is maintained by a route maintenance procedure until either the destination becomes inaccessible or the route is no longer desired. During the route discovery procedure, some of the existing source-initiated routing protocols such as DSR and AODV attempt to choose a route having the minimum Ad Hoc Networks: GPS-Based Routing Algorithm 3G Sstem s – Ad oc Ad hoc routIng protocolS