An Energy Efficient Framework for UAV-Assisted Millimeter Wave 5G Heterogeneous Cellular Networks

• Published in: IEEE transactions on green communications and networking Vol. 3; no. 1; pp. 37 - 44
• Main Authors: Chakareski, Jacob, Naqvi, Syed, Mastronarde, Nicholas, Xu, Jie, Afghah, Fatemeh, Razi, Abolfazl
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.03.2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 5G mmWave cellular networks; 5G mobile communication; Bandwidth; Cellular communication; Circuits; Downlink; Energy consumption; Energy efficiency; Energy management; Energy transmission; green communication in 5G systems; Heterogeneous networks; Millimeter waves; multi-tier heterogeneous networks; next generation networking architectures; Optimization; Power consumption; Propagation losses; Radio equipment; Resource management; UAV-enabled aerial small cells; Unmanned aerial vehicles
• ISSN: 2473-2400; 2473-2400
• DOI: 10.1109/TGCN.2019.2892141

We study downlink transmission in a multi-band heterogeneous network comprising unmanned aerial vehicle (UAV) small base stations and ground-based dual mode mmWave small cells within the coverage area of a microwave (<inline-formula> <tex-math notation="LaTeX">\mu W </tex-math></inline-formula>) macro base station. We formulate a two-layer optimization framework to simultaneously find efficient coverage radius for the UAVs and energy efficient radio resource management for the network, subject to minimum quality-of-service and maximum transmission power constraints. The outer layer derives an optimal coverage radius/height for each UAV as a function of the maximum allowed path loss. The inner layer formulates an optimization problem to maximize the system energy efficiency (EE), defined as the ratio between the aggregate user data rate delivered by the system and its aggregate energy consumption (downlink transmission and circuit power). We demonstrate that at certain values of the target SINR <inline-formula> <tex-math notation="LaTeX">\tau </tex-math></inline-formula> introducing the UAV base stations doubles the EE. We also show that an increase in <inline-formula> <tex-math notation="LaTeX">\tau </tex-math></inline-formula> beyond an optimal EE point decreases the EE.