UAV-assisted small base station ON-OFF switching in 6G cellular networks considering backhaul energy consumption

Abstract

The emergence of 6th Generation (6G) cellular networks presents an opportunity to redefine Key Performance Indicators (KPIs) necessary for high-quality communications in the 2030s. 6G aims to innovate through novel architectural designs and the utilization of higher frequency bands, alongside incorporating aerial coverage to establish a three-dimensional network framework in contrast to its predecessor, 5G. Central to this innovation are Unmanned Aerial Vehicles (UAVs), which can be used as Drone Base Stations (DBSs). Despite the energy required for UAVs to hover, they can significantly decrease energy consumption and environmental impact by replacing terrestrial cellular infrastructure and switching off underutilized or inefficient Small Base Stations (SBSs) in Ultra-Dense Networks (UDNs). This work presents an energy-efficient UAV-assisted On-Off switching methodology that considers energy usage of DBSs’ backhaul links, in contrast to previous studies. By optimizing DBS placement, user association, and power control, the approach aims to improve energy efficiency. The problem is formulated as a Mixed-Integer Nonlinear Programming (MINLP) optimization, which is then decomposed into three manageable sub-problems that are solved using proposed algorithms. This methodological framework not only alleviates the complexity associated with the original problem but also enables practical implementations in energy-constrained UAV systems, ultimately leading to improved energy efficiency compared to existing approaches. Simulation results demonstrate about 90 % improvement of energy efficiency compared to prior studies even when fewer SBSs are switched off. Furthermore, the proposed approach exhibits 95 % better energy efficiency rather than previous methods when the serving time of UAVs increases. © 2025 Elsevier B.V.