Energy-Efficient Resource Allocation in Macrocell-Smallcell Heterogeneous Networks

—Cellular users in indoor environments have difficulty to enjoy high rate services supplied only by macro base station (MBS) due to the penetration loss. Smallcell, as a complement to Macrocell, provide the enhanced coverage through constituting heterogeneous network (HetNet) with MSBs. HetNet is an effective candidate for green communications. However, the interference in HetNet is still a challenging issue. In this paper, we propose an energy-efficient subchannel and power allocation scheme (called EEmax) for a downlink of Macrocell-Smallcell HetNet. The resource allocation to maximize the Energy Efficiency (EE) for all Smallcell Base Stations (SBSs) is formulated a non-convex optimization problem with the condition of the guaranteed data rate and the cross-tier interference constraint. Through an equivalent transformation, an iterative algorithm and the closedform solution for the optimal power and resource block allocation are obtained. Simulation results show that the proposed EEmax algorithm ballance the resource efficiency both energy and spectrum efficiency.