Energy-Efficient Resource Allocation for Multi-Cell OFDM Networks

This paper studies the downlink energy-efficient resource allocation in multi-cell orthogonal frequency division multiple networks with different user distributions in each cell. A non-convex optimization problem is formulated to maximize the energy efficiency of the whole network, which takes the user distribution in each cell as a fairness weight and considers the circuit power consumption and minimum data rate requirement. The optimization problem in fractional form is transformed into an equivalent optimization problem in subtractive form using Dinkelbach method and an iterative algorithm is proposed, in which the subcarrier allocation and power allocation are implemented separately. Heuristic graph-based algorithm is first proposed to achieve the subcarrier allocation and dual decomposition method is adopted to derive the optimal power allocation strategy to maximize the energy efficiency. Simulation results show that the proposed iterative resource allocation algorithm can achieve the maximum energy efficiency in a few iterations and balance capacity between cells with different load conditions which is represented by the relative user density in this paper. Moreover, trade-off between energy-efficiency and network capacity is also unveiled.