A peer forwarding based location lookup service in mobile wireless networks

As location-based routing becomes useful in some particular scenarios, locations of mobile hosts become as important as their identifiers in ad hoc routing in mobile wireless networks. Location lookup services are henceforth needed to aid location-based routing. In this paper, we present a source routing based location lookup service that can be used as the location discovery component in a location-based routing protocol. The design goal of this service is two-fold: having high success rates on location discovery while keeping low demands on network resources. The goal of having high success rates is achieved through encouraging mobile hosts to cooperate in serving location queries. The goal of keeping overhead low is achieved through making each location query be served by a small number of hosts. Each mobile host is associated with a number of friend hosts and distributes replicas of its up-to-date location to them in order to enhance chances of answering queries about its location. Discovering or updating the location of a target host is served through the cooperation among a set of friends of the target host. The friendship among mobile hosts forms into an index structure used in our location lookup service. In order to ensure a small number of hosts participating in serving a location query, we construct the index structure into a complete binary search tree and distribute it across mobile hosts. The DSR routing protocol has been modified and used in forwarding location lookup service related packets. The path of forwarding packets reflects underlying temporary connectivities among mobile hosts. Evaluated by simulating mobile wireless networks, the performance of our location lookup service exhibits high success rates and low demands on network resources