Spectrum Sharing and Interference Management for Satellite-Terrestrial Integrated Networks: Architecture, Technologies, and Challenges

By integrating low Earth orbit (LEO) satellites with direct-to-handset technology, satellite-terrestrial integrated networks can achieve ubiquitous connectivity. However, scarce spectrum resource limits network capacity and practical applications. Therefore, spectrum sharing has emerged as a promising paradigm to fully unlock the potential of satellite-terrestrial integrated networks. To this end, this article presents a feasible framework for satellite-terrestrial integrated networks. First, the system architecture, link characteristics, interference scenarios, and typical challenges are thoroughly analyzed. Subsequently, the corresponding spectrum sharing and interference mitigation techniques are introduced to enhance ubiquitous coverage and network capacity, including adaptive beam pattern design, and coordination strategies for both wide and spot beams. Finally, several potential technical issues for satellite-terrestrial integrated networks are discussed.