Spectral Efficiency and Hybrid Beamforming for Multi-User in Airborne Integrated Sensing and Communication Systems

Autonomous aerial vehicles (AAVs) are expected to play a significant role in future Integrated Sensing and Communication (ISAC) systems. However, the performance of multi-user communications in airborne ISAC systems relies significantly on the AAV position and flight trajectory, and accurate radio propagation channel model for the scene/environment among other factors. In this paper, we propose a low-complexity AAV-enabled ISAC system model and investigate the spectral efficiency and information-outage probability. Our model employs a hybrid beamforming (HBF) design, where both the AAV and users have multiple antenna arrays which enables multi-user communications with the AAV along with the AAV's sensing capabilities of targets of interest. We propose a large-scale path loss model taking into consideration the realistic scatterers, deflection, and reflections in the scene. We investigate and analyze the average spectral efficiency for various scenarios, observe the optimal AAV altitude, and consider sensing and user interference while studying the system parameters.