Dual Decomposition Method for Energy-Efficient Resource Allocation in D2D Communications Underlying Cellular Networks

In this paper, we study the energy-efficient resource allocation for device-to-device (D2D) communication underlying cellular networks. Specifically, we aim to maximize the minimum weighted energy-efficiency (EE) of D2D links while guaranteeing the minimum data rates of the cellular links. This design, therefore, guarantees fairness for D2D links and quality-of-service (QoS) for cellular links. Toward this end, we first characterize the optimal power allocation for cellular links based on which the original resource allocation problem can be transformed into the joint sub-channel and power allocation problem for D2D links. We then propose a dual decomposition based algorithm to solve the resource allocation problem in the dual domain. Theoretical analysis demonstrates that the proposed algorithm achieves strong performance guarantee. Numerical studies show that the proposed algorithm achieves nearly optimal performance, and it performs much better than the spectrum-efficient algorithm.