Network coding games with unicast flows

To implement network coding, users need to coordinate and cooperate with respect to their strategies in terms of duplicating and transmitting side information across specific parts of the network. In unicast applications where users have no inherent interest in providing (or concealing) their information to (or from) any destinations except for their unique one, this assumption becomes critical in the face of users' autonomy. This paper addresses the issue of cooperation in unicast network coding via a game theoretic approach. Implementation of a given network coding scheme induces a network coding game among source-destination pairs (users). In a network with autonomous and rational unicast flows, the equilibrium properties (as well as efficiency) of a network coding scheme is shown to be related to the properties of the corresponding network coding game. In a simple generalization of butterfly networks with two users, we propose a network coding scheme whose capacity achieving operation coincides with users' dominant strategies.