Emerging NGSO Constellations: Spectral Coexistence with GSO Satellite Communication Systems

TL;DR

The paper tackles interference and spectrum-sharing challenges arising from NGSO mega-constellations operating in bands allocated to Fixed Satellite Service, coexisting with GSO systems. It combines a regulatory survey with technical analyses of interference scenarios (GSO-to-NGSO, NGSO-to-GSO, NGSO-to-NGSO) and interference-management strategies, including onboard and ground-based approaches and beamforming-driven mitigations, complemented by AI-enabled detection and identification. Key contributions include a synthesis of ITU-R RR framework and WRC-23 outcomes (e.g., EPFD considerations and coordination processes) and a comparison of mitigation techniques using metrics such as $NFA-EPFD$, $NDS$, $NA-INR$, and Mitigation Accuracy, along with discussions of hybrid AI-enhanced methods. The discussion emphasizes the regulatory evolution, the need for equitable access to orbit-spectrum resources, and the potential for AI to enhance real-time detection, planning, and coordination for sustainable NGSO-GSO coexistence, with practical implications for policymakers and satellite operators. The work thus provides a global, forward-looking perspective on balancing rapid NGSO deployment with the protection of existing services and spectrum resources, highlighting future regulatory items (WRC-27) and the ongoing role of AI in interference management.

Abstract

Global communications have undergone a paradigm shift with the rapid expansion of low-earth orbit (LEO) satellite constellations, offering a new space era of reduced latency and ubiquitous, high-speed broadband internet access. However, the fast developments in LEO orbits pose significant challenges, particularly the coexistence with geostationary earth orbit (GEO) satellite systems. This article presents an overview of the regulatory aspects that cover the spectrum sharing in the bands allocated to the Fixed Satellite Service between geostationary networks (GSO) and non-geostationary systems (NGSO), as well as the main interference mitigation techniques for their coexistence. Our work highlights the increased potential for inter-system interference. It explores the regulatory landscape following the World Radio Conference (WRC-23). We discuss the different interference management strategies proposed for the GSO-NGSO spectral coexistence, including on-board and ground-based approaches and more advanced mitigation techniques based on beamforming. Moving onto operational aspects related to the sharing of spectrum, we introduce recent work on interference detection, identification, and mitigation and provide our vision of the emerging role of artificial intelligence (AI) in the aforementioned tasks.

Figures (3)

• Figure 1: Interference Mitigation Techniques
• Figure 2: Performance evaluation of different interference mitigation techniques between NGSO and GSO, highlighting trade-offs in effectiveness and user demand satisfaction.
• Figure 3: Comparison of interference detection techniques in NGSO-GSO satellite communications, focusing on downlink scenarios.