Energy-efficient resource allocation in heterogeneous network with cross-tier interference constraint

Heterogeneous network (HetNet) has been investigated as a promising technique for enhancing the coverage and reducing the transmit power consumption, which has emerged as a candidate for green communications. In this paper, the energy-efficient resource allocation problem for HetNet is formulated as a non-convex optimization problem which takes into account the minimum data rate requirement, practical power model and cross-tier interference constraint. The problem is transformed into an equivalent form which can be solved by an iterative algorithm. The dual decomposition method is utilized in each iteration to obtain the closed-form solution for the optimal power and resource block allocation. The energy efficiency of the pico base station can be maximized by the proposed algorithm, although the constraint on the cross-tier interference restricts the transmit power on each resource block to fulfill the quality of service (QoS) requirement of the macro users. Simulation results are presented to evaluate the performance of the proposed algorithm in terms of the achievable spectrum and energy efficiency under different cross-tier interference constraints.