Attenuation Modeling for Atmospheric Turbulence in Terahertz UAV Channels

Terahertz (THz) wireless communications have the potential to realize ultra-high-speed data transfer with miniaturized devices for unmanned aerial vehicle (UAV) communications. Existing THz UAV channel models assume a homogeneous medium along the propagation path. However, the atmospheric turbulence due to random airflow leads to temporal and spatial inhomogeneity of the communication medium, motivating the analysis and modeling of the influence of atmospheric turbulence on $\mathbf{T H z}$ wave propagation. In this paper, we statistically modeled the attenuation effect of turbulence on THz UAV channels. Specifically, the refractive index structure constant, as a critical statistical parameter characterizing the influence of turbulence on channel medium, is first investigated. Then, the scintillation characteristic and attenuation of the THz communications caused by atmospheric turbulence are modeled, where the scintillation effect is characterized by a Gamma-Gamma distribution, and the turbulence attenuation as a function of altitude and frequency is derived. Numerical simulations on the refractive index structure constant, scintillation, and attenuation in the THz band are presented to quantitatively analyze the influence of turbulence for THz UAV channels. It is discovered that THz turbulence can lead to at most 10 dB attenuation with frequency less than 1 THz and distance less than $10 \mathbf{k m}$.