Trusted Greedy Perimeter Stateless Routing

Ad-hoc networks generally comprise of mobile wireless nodes having limited communication and computation resources. These nodes execute special routing protocols, which help to establish multi-hop communication despite a dynamic topology. The greedy perimeter stateless routing (GPSR) protocol is one such routing protocol that is frequently used to establish routes in an ad-hoc or sensor network. However, for its precise execution, it is imperative that all nodes depict sustained benevolent behaviour. However, such an altruistic setting would never work in a wireless environment, which is intrinsically physically insecure. Consequently, participating malicious nodes may launch an array of attacks against the routing protocol leading to route severing, elongation or loop creation. In this paper, we present an improved variant of the GPSR protocol that uses the inherent characteristics of the routing process to assess the trust in the network nodes. These trust levels are then used to influence the routing decisions so as to circumvent malevolent nodes in the network. Extensive simulations indicate that the packet delivery ratio of the trusted GPSR protocol surpasses that of the standard GPSR by as much as 30% when as many as 50% of the nodes are acting maliciously in the network.