Spectrum Utilization Efficiency Analysis in 3D UAV Networks

This paper investigates the Spectrum Utilization Efficiency (SUE) and average link Spectral Efficiency (SE) of 3D communication systems comprised of Unmanned Aerial Vehicles (UAVs). In particular, we characterize the impact of key parameters such as frequency reuse cell radius, normalized frequency reuse distance, and path-loss exponent on the SUE and SE of systems in 3D space. We derive analytical expressions for SUE and SE under both free-space and log-normal pathloss models and validate them through simulations. Our results indicate that while increasing the normalized frequency reuse distance decreases SUE, it improves the average link SE. Furthermore, smaller cell radii or larger pathloss exponents can improve SUE, offering important insights for optimizing frequency reuse strategies in UAV-based networks in 3D space. This study lays the groundwork for future exploration of spectrum management and dynamic spectrum sharing (DSS) in dynamic and complex integrated aerial and ground communication environments.