Geometry-driven Scheme for Geocast Routing in Mobile Ad Hoc Networks

This paper considers the problem of geocasting in mobile ad hoc networks. Geocasting, a variation on the notion of multicasting, is a mechanism to deliver messages of interest to all nodes within a certain geographical target region. Although several geocasting protocols have already been proposed for mobile ad hoc networks, with the goal of achieving an efficient message delivery, most of these algorithms consider a "single" target region only and therefore multiple transmissions should be initiated separately by the message source when more than one target regions need to receive the same geocast messages. This causes significant performance degradation, especially as the number of geocast regions increase. To solve this problem, we propose a novel scheme driven by geometry, named GGP (geometry-driven geocasting protocol). In this scheme, the geometric concept of "Fermat point" is utilized to determine the optimal junction point among multiple geocast regions from the source node, and hence to reduce the overhead of message delivery, while maintaining a high delivery ratio