Energy-Efficient Resource Allocation for Time-Varying OFDMA Relay Systems With Hybrid Energy Supplies

This paper investigates the energy-efficient resource allocation for orthogonal frequency-division multiple-access relay systems, where the system is supplied by the conventional utility grid and a renewable energy generator equipped with a storage device. The optimal usage of radio resource depends on the characteristics of the renewable energy generation and the mobile traffic, which exhibit both temporal and spatial diversities. The Lyapunov optimization method is used to decompose the problem into the joint flow control, radio resource allocation, and energy management without knowing
a priori
knowledge of system statistics. It is proven that the proposed algorithm can result in close-to-optimal performance with capacity-limited data buffer and storage device. Simulation results show that the flexible tradeoff between the system utility and the conventional energy consumption can be achieved. Compared with other schemes, the proposed algorithm demonstrates better performance.