On the significance of context information in node discovery

In short-range wireless communications, node discovery is an initial step to initialize communication with other nearby mobile terminals or networks. The existing techniques for node discovery are based on traditional scanning, which is expensive in terms of energy and drains out mobile battery swiftly; hence mobile devices with hybrid character, containing ad hoc and infrastructure access, need mechanisms that keep them connected in an energy efficient way. In this paper, we propose a node discovery mechanism in which context information provides knowledge and guidance to the searching mobile terminal about the nearby mobile terminals or clusters to initialize cooperative communications. The cluster is UWB based. We modify the UWB beacon IEs and embed our own beacon IEs to represent different pieces of information e.g. willingness, battery level, hibernation mode etc. The clusterhead of each cluster collects and packs the information from member devices into a context list, and sends it to the WiMAX base station. The context list is then provided to searching MTs to discover nearby clusters. The simulation results show that our approach saves 50% of energy consumption by utilizing context information compared to normal scanning process.