Reputation-based system for encouraging the cooperation of nodes in mobile ad hoc networks

In a mobile ad hoc network, node cooperation in packet forwarding is required in order for the network to function properly. However, some selfish nodes might intend not to forward packets in order to save resources for their own use. To discourage such behavior, we propose a reputation-based system to detect selfish nodes and respond to them by showing that being cooperative will benefit them more than being selfish. In this paper, besides cooperative nodes and selfish nodes, we introduce a new type of node called a suspicious node. These suspicious nodes will be further investigated and if they tend to behave selfishly, we could take some actions against them like we do to selfish nodes to encourage them to be cooperative. We introduce the use of a state model to decide what we should do or respond to nodes in each state. In addition, we introduce the use of a timing period to control when the reputation should be updated.