HOWL: an efficient route discovery scheme using routing history in ad hoc networks

We propose an efficient route discovery scheme for mobile ad hoc networks called Hop-Wise Limited broadcast (HOWL). HOWL executes an efficient route discovery by predicting current location of destination using hop counts of previously used routes. Furthermore, we introduce characterized environmental indicators (CEI), namely node density, average hop count of route, and frequency of link failure, which characterizes real world environments with the constraint that parameters such as speed or transmission range are similar for every node in the network. CEI is also applicable to simulation environments. We have implemented a preliminary phase of HOWL as an extension to dynamic source routing (DSR), which uses network-wide broadcasts as a means of sending route request messages, on ns-2 network simulator. Simulations show that HOWL is especially effective when the node density is low, average hop count of route is short, or frequency of link failure is high where up to 10 % reduction in overhead and approximately 5 % reduction in latency were demonstrated.