A Novel Mobile Awareness Mechanism in Wireless Ad Hoc Networks without GPS

Abstract

A mobile Ad Hoc Network is a wireless multihop network without any existing infrastructure. In such a networking environment, each mobile node can move freely such that the network topology cha nges dynamically. This may frequently result in the link breakdown, thus causing network inefficiency and data loss. In this paper, we develop a simple heuristic mechanism to characterize the instant mobility of network nodes. We assume that all network nodes can move arbitrarily, and none of them is equipped with any positioning device (such as the GPS system). Each mobile node is (at any time) classified as either a low mobility node or a high mobility node. A mobile node estimates its own mobility type by comparing the signal strength of consecutive received messages sent by its low mobility neighboring nodes. It then broadcasts this mobility type information to its neighbors. The mobility estimation algorithm is thus fully distributed and self organized. Simulation results have revealed that such a mobility estimation algorithm can achieve a reasonably high degree of accuracy for a wide range of networking environments. Once the nodes can be classified as either high mobility or low mobility, we can take the advantage of characteristic of low mobility nodes for some applications, such as path setup, cluster head election.