  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.
