Trust-Based Routing In Ad Hoc Networks

Ad hoc networks are multihop wireless mobile communication networks in which nodes are equipped with wireless devices. The mobile nodes in Ad hoc networks play both roles of router and host. Nodes forward packets for each other, and with the help of relays, nodes are able to communicate with nodes outside wireless communication range, which is multihop communication.Examples of applications for Ad hoc networks range from military operations and emergency disaster relief to community networking and virtual class. In Ad hoc networks, routing schemes fall into two catagories : one follows the form of Store-Forward and the other follows the form of Store-Carry-and-Forward. Different schemes can be utilized in different scenarios. The former requires an existing link between source node and destination node when data forwarding. On the other hand, the latter schemes can be used in Ad hoc networks characterized by long propagation delays and/or intermittent connectivity. Nodes in these Ad hoc networks will carry messages until encountering another proper node.The characteristics of Ad hoc networks are nodal mobility, continuously changing topology, physical abilities and wireless communication. All of these characteristics together not only facilitate but also constrain the applications of Ad hoc netoworks. Evaluating nodal trust value is a good way to overcome some disadvantages in Ad hoc networks. In our paper, we first define trust of nodes in Ad hoc networks : to what degree node A trust node B's ability to forward messages. We do not only consider whether node B is malicious but also determine other six factors. Based on the six influential factors, we propose Multi-Factors Trust Evaluation Scheme. And then design DSR protocol based on this trust evaluation scheme. By comparison, the results of simulations attest that Multi-Factors Trust Evaluation Scheme outperforms CONFIDANT.Besides, we do research on routing of Store-Carry-and-Forward, and propose a routing algorithm based on Multi-Factors Trust Evaluation Scheme, called TrSoc Routing Algorithm. In Ad hoc networks, nodes movements are characterized by the properties of social networks. With the help of concepts of social networks, Trsoc Routing Algorithm builds nodal trusted community based on the trust of nodes. Trsoc Routing Algorithm assures that the next-hop node is trustworthy. In this paper, we illustrate the process of TrSoc Routing Algorithm. In the end, we use OPNET to do three simulations and design four different scenarios of Ad hoc networks to examine the function of TrSoc Routing Algorithm. The results of simulations show that TrSoc Routing Algorithm performs good routing and have a high delivery ratio in Ad hoc networks both with and without malicious nodes.