An Energy Efficiency Optimization Algorithm Based on the Factor for Portion of Time Division in Backhaul-Constrained Ultra Dense HetNets

The ultra dense networks (UDN) are considered as a key technology of 5G for its ability to increase communication capacity. However, the problem of constrained backhaul and the lack of energy which is caused by micro base station without power supply equipment are two mainly bottlenecks of UDN. In order to solve the problem of low micro base station's energy efficiency (MIEE) due to constrained backhaul, we propose an energy efficiency optimization algorithm based on the factor for the portion of time division (FPTD). The optimization problem considers a joint design of downlink precoding, power allocation and the FPTD, meanwhile, we utilize first order Taylor convex approximation (FOTCA), convex slack variable and one-dimensional search method (ODS) to solve. Simulation results show that the proposed FPTD-based energy efficiency optimization algorithm (FEEOA) is improved with much better energy efficient compared with the primitive scheme without FPTD, and more throughputs can be transmitted at the same energy consumption.