Optimal energy efficient strategy for cooperative spectrum sharing networks

Energy consumption is one of the concerned focuses in current wireless communication network, so more and more network designs take green communication into consideration. This paper presents an optimal energy efficient strategy for the cooperative spectrum sharing networks. In the proposed network, secondary users cooperate to improve primary user´s transmission efficiency, in exchange for the use of the channel licensed by the primary user. We propose the system model of cooperative spectrum sharing network, and the optimal power and time allocation of multiple cooperative users is given, based on the criterion of minimal energy consumption. Karush-Kuhn-Tucker (KKT) conditions are utilized to solve the optimal problems. The simulation results show that, system throughput grows as the number of cooperative users increases, while the system energy efficiency doesn´t go the same way. As for energy efficiency, our results show that selecting appropriate number of cooperative users can make the system optimally energy efficient.