Energy Efficient Resource Allocation in D2D-Assisted Heterogeneous Networks with Relays

Heterogeneous networks (HetNets) supported with relays and device to device communication can be considered as a promising solution to realize the ambitious targets of the future fifth generation networks in terms of energy efficiency and capacity. HetNets necessitate optimal power allocation, spectrum resource allocation, and cell selection to meet the quality of service requirements. In this paper, we formulate energy efficiency maximization problem in terms of resource allocation and cell selection for HetNets, where objective is to maximize the network throughput per unit network power consumption. Formulated optimization problem is non-linear fractional programming problem. We use Charnes-Cooper transformation to convert proposed fractional programming problem into concave optimization problem. We propose outer approximation algorithm (OAA) to solve the converted concave optimization problem. The proposed algorithm is evaluated by extensive simulation work. The performance of ε-optimal solution obtained by OAA method is shown for different network parameters, such as number of users, required date rate, and capacity of network.