A Simple Analytical Ergodic Capacity Approximation for Sub-Terahertz Band Drone-to-Ground Communication

As the bridge between optical communication and radio frequency communication, the terahertz (THz) band has unique channel behavior depending on its inherent characteristics stemming from high frequency. However, obtaining statistical performance results requires a significant amount of time. In this paper, we derive an elevation angle, altitude, and frequency dependent analytical model for ergodic capacity at the sub-THz (0.1-0.3 THz) band under turbulence and beam misalignment effects. In this model, we work on the drone-to-ground communication scenario, considering altitudes ranging from 40 meters to 200 meters, and elevation angles ranging from 45 degrees to 90 degrees. The proposed solution provides high-accuracy approximation results (where its normalized root mean square error is less than 0.001) with very short prediction time while yielding a simple closed-form expression.