Enabling mobile traffic offloading via energy spectrum trading

Green communications has received much attention recently. For mobile networks, the base stations (BSs) account for more than 50% of the energy consumption of the networks. Therefore, reducing the power consumption of BSs is crucial to greening mobile networks. In this paper, we propose a novel energy spectrum trading (EST) scheme which enables the macro BSs to offload their mobile traffic to Internet service providers' (ISPs') wireless access points by leveraging cognitive radio techniques. Since the ISP's wireless access points are usually closer to the mobile users, the energy and spectral efficiency of mobile networks are enhanced. However, in the EST scheme, achieving optimal mobile traffic offloading in terms of minimizing the energy consumption of the macro BSs is NP-hard. We thus propose a heuristic algorithm to approximate the optimal solution with low computation complexity. We have proved that the energy savings achieved by the proposed heuristic algorithm is at least 50% of that achieved by the brute-force search. Simulation results demonstrate the performance and viability of the proposed EST scheme and the heuristic algorithm.