Home agent based location update and destination search schemes in ad hoc wireless networks

All previously proposed position based routing algorithms for wireless ad hoc networks were based on forwarding the actual message along multiple paths toward an area where destination is hopefully located (except our previous report [SV]). In [SV], we proposed to reduce significantly the communication overhead by changing the routing strategy. The source node issues several search 'tickets' (each ticket is a 'short' message containing sender's id and location, destination's best known location and time that location is reported, and constant amount of additional information) that will look for the exact position of destination node. When the first ticket arrives at the destination node D, D will report back to source with brief message containing its exact location, and possibly creating a route for the source. The source node then sends full data message ('long' message) toward exact location of destination. In this paper, we propose to use a home agent based strategy for location updates and destination searches. Each node designates a certain circular area as its home agent, and informs other nodes about it. He subsequently sends its location update messages only to the nodes located in its home agent (in addition to local updates of its position). Destination search is then performed by sending a query toward its home agent, which will supply the latest available information about the position, and forward the request toward destination. We show through simulation that the proposed routing and location update schemes provide high success rates with reasonable communication overhead.