Interference Mitigation in LEO Satellite Communications: A Multi-Timescale Perspective

Abstract

With the continued deployment of low Earth orbit (LEO) satellite constellations, spectrum resources are becoming more limited. As a result, satellite-to-ground links face many types of strongly coupled interference in complex electromagnetic environments. This interference includes non-intentional interference caused by different systems and devices under spectrum sharing, and also malicious jamming with adversarial intent. The effects of interference exhibit multi-scale temporal and spatial evolution characteristics. Most existing surveys discuss mitigation methods for individual interference types separately, but lack systematic approaches to deal with complex environments where different types of interference exist together. This survey reviews interference mitigation techniques in LEO satellite communications from a novel perspective. Specifically, we first summarize the interference scenarios for LEO satellite communications based on the interference intent. Then, we propose a novel taxonomy based on the timescale at which a mitigation strategy takes effect. This taxonomy provides a unified framework to capture the multi-timescale nature of interference and helps to find solutions more systematically. With this taxonomy, existing methods can be grouped into three paradigms: long-term planning, short-term scheduling, and instantaneous decision-making. For each paradigm, we review representative methods, applicable conditions, and key limitations. In addition, this survey discusses recent advances in cross-timescale coordinated mitigation, as well as key challenges in multi-satellite coordination. Finally, we outline several promising directions for future research.