Modeling Security and Cooperation in Wireless Networks Using Game Theory

This research involves the design, development, and theoretical demonstration of models resulting in integrated misbehavior resolution protocols for ad hoc networked devices. Game theory was used to analyze strategic interaction among independent devices with conflicting interests. Packet forwarding at the routing layer of autonomous ad hoc networks was investigated. Unlike existing reputation based or payment schemes, this model is based on repeated interactions. To enforce cooperation, a community enforcement mechanism was used, whereby selfish nodes that drop packets were punished not only by the victim, but also by all nodes in the network. Then, a stochastic packet forwarding game strategy was introduced. Our solution relaxed the uniform traffic demand that was pervasive in other works. To address the concerns of imperfect private monitoring in resource aware ad hoc networks, a belief-free equilibrium scheme was developed that reduces the impact of noise in cooperation. This scheme also eliminated the need to infer the private history of other nodes. Moreover, it simplified the computation of an optimal strategy. The belief-free approach reduced the node overhead and was easily tractable. Hence it made the system operation feasible. Motivated by the versatile nature of evolutionary game theory, the assumption of a rational node is relaxed, leading to the development of a framework for mitigating routing selfishness and misbehavior in Multi hop networks. This is accomplished by setting nodes to play a fixed strategy rather than independently choosing a rational strategy. A range of simulations was carried out that showed improved cooperation between selfish nodes when compared to older results. Cooperation among ad hoc nodes can also protect a network from malicious attacks. In the absence of a central trusted entity, many security mechanisms and privacy protections require cooperation among ad hoc nodes to protect a network from malicious attacks. Therefore, using game theory and evolutionary game theory, a mathematical framework has been developed that explores trust mechanisms to achieve security in the network. This framework is one of the first steps towards the synthesis of an integrated solution that demonstrates that security solely depends on the initial trust level that nodes have for each other

Cooperation In Ad Hoc Networks With Noisy Channels

An underlying assumption of multi-hop data communication in ad hoc networks is that the nodes forward each others\u27 packets. An important challenge in such scenario is to attain mutual cooperation. This paper provides a game theoretic solution to enforce cooperation in ad hoc network in the presence of channel noise. We focus on the packet forwarding process and model it as a hidden action game with imperfect private monitoring. We propose a state machine based strategy to reach Nash Equilibrium. The equilibrium is proved to be a sequential equilibrium with carefully designed system parameters. Furthermore, we extend our discussion to a general ad hoc network scenario by refining the strategy profiles to handle multi-hop packet forwarding. The simulation results illustrate the efficiency of the proposed forwarding strategies. In addition, network throughput performance is measured with respect to parameters like channel loss probability, route hop count and mobility. Results suggest that the performance due to our proposed strategy is in close agreement with that of unconditionally cooperative nodes. © 2009 IEEE