Energy Efficient Relaying Games in Cooperative Wireless Transmission Systems

In wireless networks, intermediate nodes are often used as relays to reduce the transmission energy required to deliver a message to an intended destination. The selfishness of autonomous nodes, however, raises concerns about their willingness to expend energy to relay information for others. This paper considers the effect of selfishness on energy efficiency using a non-cooperative game theoretic approach. A two-source relaying game is formulated for both non-fading and fading scenarios. We show that cooperative transmission with optimum energy allocation is a Nash Equilibrium in non-fading channels when the sources are sufficiently patient. In fading channels, cooperative transmission with optimum energy allocation is also a Nash Equilibrium when a ceiling is applied to the relay energy of each source. Simulation results show that sources acting in their own self-interest can achieve an energy efficiency close to that of centrally optimized energy allocation in many cases.