Using location information to reduce the route search in tactical radio networks

Information about where units of interest are located is very important in military operations. Clearly, whenever such information is available it can be used to simplify the routing in multi-hop ad hoc networks. In recent years, many distributed protocols have been proposed for routing in mobile ad hoc networks, especially so-called on demand (or reactive) protocols. In reactive routing, a route from the source to the destination is searched when needed. Many of the reactive protocols use a route searching mechanism where a route request is flooded in the network. This paper investigates this search procedure and tries to reduce it to a limited region with the aid of location information. Different search regions, applied both in a static and an adaptive way, are investigated. In particular, the aim of our investigation is to see how the terrain effects the efficiency of location information aided routing. The simulations show that there is a lot to gain by using location information, if this is available and reliable, in order to limit the route search. In the tested networks we reduced the route search overhead by up to 70%, compared with flooding. In these cases, the increase in number of hops it takes to find the route is less then 20%.