Analysis of Scintillation Effects in Terahertz Band Satellite Communications for 6G and Beyond

Scintillation due to atmospheric turbulence is one of the effects challenging the reuse of extremely wideband and high-rate optical satellite-to-satellite communication systems for satellite-to-Earth and Earth-to-satellite transmissions. In this article, we study the possibility of utilizing links in the terahertz (THz) frequency bands for these uplink and downlink transmissions instead. Built upon the physics-based model, originally developed for optical wave propagation, we present a mathematical framework for the THz signal scintillation to analyze atmospheric turbulence's impact on ground-satellite and airplane-satellite connections. Our results indicate that, while the scintillation still significantly impacts the power of the received THz signal (especially at lower elevation angles and under specific weather conditions), the effect is drastically less profound than the extreme losses the optical link will experience in the same weather conditions. We further explore a notable asymmetry of up to 10 dB between uplink and downlink losses. Finally, we illustrate that, even at relatively low airplane altitudes, the airplane-to-satellite link is much less affected than the Earth-to-satellite link, making THz communications a promising candidate technology for future high-rate airplane connectivity systems as a part of 6G and beyond.