A Universal Attenuation Model of Terahertz Wave in Space-Air-Ground Channel Medium

TL;DR

This paper introduces a universal attenuation model for Terahertz waves in space-air-ground channels, accounting for particle interactions, and evaluates their impact on propagation loss and network capacity in various SAGIN scenarios.

Contribution

It develops a novel physical model for THz wave attenuation in SAGIN, considering particles like molecules and electrons, and assesses its implications for network performance.

Findings

Attenuation effects are negligible above 50 km altitude.

Attenuation due to particles is significant below 50 km.

THz SAGIN capacity varies across different space-ground-sea configurations.

Abstract

Providing continuous bandwidth over several tens of GHz, the Terahertz (THz) band (0.1-10 THz) supports space-air-ground integrated network (SAGIN) in 6G and beyond wireless networks. However, it is still mystery how THz waves interact with the channel medium in SAGIN. In this paper, a universal space-air-ground attenuation model is proposed for THz waves, which incorporates the attenuation effects induced by particles including condensed particles, molecules, and free electrons. The proposed model is developed from the insight into the attenuation effects, namely, the physical picture that attenuation is the result of collision between photons that are the essence of THz waves and particles in the environment. Based on the attenuation model, the propagation loss of THz waves in the atmosphere and the outer space are numerically assessed. The results indicate that the attenuation effects except free space loss are all negligible at the altitude higher than 50 km while they need to be considered in the atmosphere lower than 50 km. Furthermore, the capacities of THz SAGIN are evaluated in space-ground, space-sea, ground-sea, and sea-sea scenarios, respectively.