A survey on incentive mechanism of delay tolerant networks

Delay Tolerant Networks (DTNs) are new solutions that can cope with hash conditions and span across multiple networks. In these networks, end-to-end connectivity is intermittent. DTNs enable user devices to self-organize to connect to functional base station or other users through multiple hops. In traditional DTNs, they are assumed to be willing to help other nodes for packet forwarding. But in the real scenario of DTNs deployment, the nodes are often battery operated. As a result, the energy of the nodes is limited. Due to the nodes are energy constraint, the selfish behaviors may occur among the nodes, say, the nodes may not be willing to forward data for others. So the assumption that all the nodes are cooperative is unrealistic. The way to stimulate the nodes taking part in the relaying of data is often called incentive mechanism. In this paper, we analyze the selfish issue of DTNs and show the importance of settling the selfish problem. Then we display four types of typical examples of the incentive mechanisms. They are virtual currency based incentive mechanism, credit-based incentive mechanism, game-theory-based incentive mechanism and combined incentive mechanism. We analyze them respectively and comparative studies are also stated. Finally we make a conclusion and discuss the open research issues in the future.