Abstract
Recent research shows that in wireless wide area networks (WWANs), users who subscribe to multicast traffic from WWAN can exchange network-coded packets with one another via their secondary radio interfaces such as Wi-Fi in order to efficiently recover lost packets from the WWAN. Different from existing works which assume users are cooperative, in this work, we model the users as selfish players in the network-coding based peer-to-peer packet repairing game. To stimulate the users' cooperation, we introduce a payment-based incentive mechanism in the packet repairing game. The utility function of a user/player is also formulated to reflect both the number of useful packets and the available resource. Through analysis of the packet repairing game, we show that the optimal strategy for a user can be derived only with its local information. The impact of the pricing rules and the convergence conditions of the packet repairing game is also analyzed. We show theoretically as well as by simulation that under proper conditions, the packet repairing game can converge to the best case where each user can acquire all of its missing packets. Via computer simulations, we also show that with the proposed selection criteria, the packet repairing game is both effective and efficient: not only can the utilities of the players be greatly improved, but also the convergence time of the game and the utility gain of the players are comparable to those of the ideal case where every user is always willing to forward packets to others.