Channel Modeling and Analysis of Inter-Small-Satellite Links in Terahertz Band Space Networks

Small satellites have shorter development cycles and lower costs than the traditional satellites in low-earth orbits (LEOs) and geostationary orbits (GEOs). These advantages and the ultra-wide spectrum availability in the Terahertz (THz) band enable profound potentials for inter-satellite links (ISLs) to achieve ultra-high throughput in both near-Earth and deep-space orbits. In this paper, the ISL channels at THz band are characterized and their link capacity is analyzed. First, the propagation channel effects in both Earth’s upper atmosphere and deep space are investigated to demonstrate the feasibility of THz band for ISLs. Second, an orbital perturbation model for satellite formation flying is proposed and analyzed with actual ephemeris information. Finally, a channel model is developed to investigate the diversity in both polarization and frequency domain for THz band inter-small-satellite communications. Our numerical results demonstrate that: 1) the ionospheric plasma does not affect the THz band signal propagation in near-Earth orbits; 2) the beam misalignment loss can be characterized by orbital perturbation factors; and 3) the ISLs in THz band can utilize the diversity techniques to achieve high throughput in both near-Earth and deep-space links.