An Enforceable Scheme for Packet Forwarding Cooperation in Network-Coding Wireless Networks With Opportunistic Routing

The performance of wireless networks can be significantly improved by using network coding with opportunistic routing. In such a wireless network, selfish nodes may not cooperate when they are supposed to forward packets. This fundamental cooperation problem in packet forwarding is closely related to the incentive problem in network-coding wireless networks with opportunistic routing, and to the incentive-compatible packet-forwarding problem in conventional wireless networks, but different from both of them. In this paper, we propose incentive-compatible packet opportunistic forwarding for network-coding wireless networks (INPAC), a solution using a combination of game-theoretic and cryptographic techniques. We formally prove that, if INPAC is used, then being cooperative in packet forwarding is a subgame perfect equilibrium. That is, nodes have incentives to follow the protocol and forward packets. We have implemented and evaluated INPAC on the Orbit Lab test bed. Our evaluation results verify the incentive compatibility of INPAC and also its efficiency.