PIS: A Practical Incentive System for Multihop Wireless Networks

In multihop wireless networks (MWNs), the mobile nodes usually act as routers to relay other nodes' packets to enable new applications and enhance network performance and deployment. However, selfish nodes may not cooperate and make use of the cooperative nodes to relay their packets, which has a negative effect on network fairness, security, and performance. Incentive systems implement micropayment in the network to stimulate the selfish nodes to cooperate. However, micropayment schemes have originally been proposed for Web-based applications; therefore, a practical incentive system should consider the differences between Web-based applications and cooperation stimulation. In this paper, first, these differences are investigated, and a payment model is developed for the efficient implementation of micropayment in MWNs. Second, based on the developed payment model, an incentive system is proposed to stimulate the nodes' cooperation in MWNs. Third, a reactive receipt submission mechanism is proposed to reduce the number of submitted receipts and protect against collusion attacks. Extensive analysis and simulations demonstrate that our incentive system can secure the payment and reduce the overhead of storing, submitting, and processing payment receipts significantly, which can improve the system's practicality due to the high frequency of low-value payment transactions.