Improving MANET Routing Protocols Through the Use of Geographical Information

Abstract

This paper provides a summary of our research study of the location-aided routing protocols for mobile ad hoc networks (MANET). This study focuses on the issue of using geographical location information to reduce the control traffic overhead associated with the route discovery process of the ad-hoc on demand distance vector (AODV) routing protocol. AODV performs route discovery by flooding the whole network with the route request packets. This results in unnecessarily large number of control packets traveling through the network. In this paper, we introduced a new Geographical AODV (GeoAODV) protocol that relies on location information to reduce the flooding area to a portion of the network that is likely contains a path to destination. Furthermore, we also compared GeoAODV performance with that of the Location Aided Routing (LAR) protocol and examined four mechanisms for reducing the size of the flooding area: LAR zone, LAR distance, GeoAODV static, and GeoAODV rotate. We employed OPNET Modeler version 16.0 software to implement these mechanisms and to compare their performance through simulation. Collected results suggest that location-aided routing can significantly reduce the control traffic overhead during the route discovery process. The comparison study revealed that the LAR zone protocol consistently generates fewer control packets than other location-aided mechanisms. However, LAR zone relies on the assumption that location information and traveling velocities of all the nodes are readily available throughout the network, which in many network environments is unrealistic. At the same time, the GeoAODV protocols make no such assumption and dynamically distribute location information during route discovery. Furthermore, the collected results showed that the performance of the GeoAODV rotate protocol was only slightly worse than that of LAR zone. We believe that even though GeoAODV rotate does not reduce the control traffic overhead by as much as LAR zone, it can become a preferred mechanism for route discovery in MANET.