Analysis of 3D Space Spectrum Utilization in UAV-Enabled Cellular Networks

The efficient utilization of the electromagnetic spectrum is crucial for the performance and coexistence of emerging 5G-Advanced and 6G/Next-G wireless communication networks operating in 3D space such as unmanned aerial vehicle (UAV)-assisted and high altitude platform station (HAPS)-based systems. This paper introduces a comprehensive analytical framework for evaluating spectrum utilization efficiency (SUE) and link spectral efficiency (SE) in aerial communication systems, focusing on the general scenario of partially loaded networks. Leveraging a frequency reuse architecture to model the impact of co-channel interference, closed-form expressions for the upper and lower bounds of SE and SUE under best-case and worst-case scenarios are derived. The proposed framework incorporates probabilistic modeling of user distribution and channel utilization in analyzing multi-UAV next generation node B (UAV-gNB) and multi-interference scenarios under different propagation models, including free-space path loss, log-normal fading, and Nakagami-m fading. Simulations validate the analytical results and the proposed framework, demonstrating its potential utility in optimizing spectrum usage and interference management in 3D communication networks. The findings provide actionable insights for designing and deploying efficient and scalable aerial communication networks with improved spectrum utilization and SE performance.