Challenges and Solutions in Spectrum Management for Direct Satellite-to-Device Communication

To meet the demands of the sixth-generation (6G) wireless system for ubiquitous, always-on connectivity, direct satellite-to-device (DS2D) communication has emerged as a promising solution to provide seamless coverage in underserved areas while reducing reliance on terrestrial infrastructure. However, DS2D faces critical spectrum management challenges, including limited available spectrum, high bandwidth demands, and potential interference due to spectrum coexistence. In this article, we conduct a systematic analysis of DS2D spectrum utilization patterns, recent standardization efforts, and regulatory frameworks governing DS2D operations. In addition, we explore advanced spectrum sharing technology of DS2D and its potential application scenarios. Finally, we analyze the future directions and challenges of spectrum sharing between LEO-LEO satellites, GEO-LEO satellites, and satellite-terrestrial cellular systems to improve spectrum utilization efficiency and promote the deep integration of DS2D in the 6G system.