Performance evaluation of multi-shell LEO satellite constellations in 6G communication systems

With the objective of achieving global coverage and seamless connectivity envisioned for sixth-generation (6G) wireless communication systems, low Earth Orbit (LEO) satellite systems are rapidly evolving with multi-layered constellations. Therefore, evaluating LEO satellite performance from ground user’s perspective is thus essential to design an efficient network. The article presents a dynamic link topology for multi-shells LEO satellite constellations, providing fixed ground cells with communication services via gateway station. The proposed model thoroughly examines the intricate relationship between satellite visibility, elevation angle constraints, and slant distance, highlighting their impact on link quality and service availability. To realistically capture satellite dynamics and assess downlink performance, the model defines service duration feasibility and classifies service conditions according to elevation angles, emphasizing optimal ranges for maintaining signal quality. The channel model incorporates various loss components, including basic path loss, atmospheric attenuation, and scintillation effects, each dependent on the slant distance and elevation angles. Comprehensive analytical expressions for key determinants including signal received power, access probability, traffic data loads, and Doppler shift are derived. The simulation results show an improvement in the power of the received signal with higher elevation angles, directly enhancing the access probability of visible satellites for a ground user. Furthermore, the results also demonstrate temporal variations in traffic data of satellites at a gateway station and provide insights into doppler shift dynamics across diverse constellations.