INPAC: An Enforceable Incentive Scheme for Wireless Networks using Network Coding

Wireless mesh networks have been widely deployed to provide broadband network access, and their performance can be significantly improved by using a new technology called network coding. In a wireless mesh network using network coding, selfish nodes may deviate from the protocol when they are supposed to forward packets. This fundamental problem of packet forwarding incentives is closely related to the incentive compatible routing problem in wireless mesh networks using network coding, and to the incentive compatible packet forwarding problem in conventional wireless networks, but different from both of them. In this paper, we propose INPAC, the first incentive scheme for this fundamental problem, which uses a combination of game theoretic and cryptographic techniques to solve it. We formally prove that, if INPAC is used, then following the protocol faithfully is a subgame perfect equilibrium. To make INPAC more practical, we also provide an extension that achieves two improvements: (a) an online authority is no longer needed; (b) the computation and communication overheads are reduced. We have implemented and evaluated INPAC on the Orbit Lab testbed. Our evaluation results verify the incentive compatibility of INPAC and demonstrate that it is efficient.