Adaptive Inter-Orbital LEO Satellite THz Communication Under Satellite Position and Attitude Disturbances

Inter-satellite communication (ISC) is a critical component of low Earth orbit (LEO) satellite communication systems, enabling seamless data exchange between satellites within the same or across different orbital planes. This paper investigates the impact of position and attitude perturbations caused by gravitational forces, the J2 effect, aerodynamic torques, and Earth’s magnetic field between inter-orbital LEO satellite pairs on ISC channels. It reveals that such perturbations significantly degrade the LEO ISC link performance at the terahertz (THz) band. To address this challenge, a novel statistical symbol-level power and modulation adaptation (SSL-PMA) algorithm is proposed to mitigate the effects of the perturbations, enhance spectral efficiency, and reduce transmission power consumption under varying perturbation levels. Simulation results demonstrate that the proposed algorithm achieves substantial spectral efficiency gains over conventional adaptive and non-adaptive schemes, maintaining bit error rate (BER) performance comparable to or better than that of fixed modulation schemes across different perturbation levels. Notably, transmission power savings of up to 40% are achieved at inter-plane angles of 90◦ and 150◦, with slightly lower savings at 30◦. These findings highlight the potential of the proposed SSL-PMA algorithm for efficient and adaptive transmission in future THz-band inter-satellite communication systems.