Overview of Dynamic Spectrum Sharing Between LEO Satellites and Mobile Networks: Enabling Seamless Connectivity and Coexistence in 6G

In recent years, we have witnessed an acceleration in the growth of wireless communication technologies, particularly Low Earth Orbit (LEO) satellite constellations, with the direction towards integration with terrestrial networks in the domain of sixth-generation networks. This evolution promises to provide high-speed internet, low-latency communication, and extended global coverage. However, the availability of sufficient spectrum has become a critical challenge. The purpose of this paper is to review existing literature on Dynamic Spectrum Sharing (DSS) between LEO and geostationary satellites, as well as between LEO satellites and terrestrial networks. The contribution of this research lies in providing insights into key topics, including LEO constellation development, DSS techniques, spectrum regulatory compliance, current and future mobile satellite frequency allocations, and emerging trends related to providing direct connectivity to user equipment from space. The findings emphasize the importance of DSS as a vital technique to address spectrum scarcity and ensure coexistence between satellites and terrestrial networks. Based on the reviewed literature, we propose three approaches for future research directions that are crucial for providing additional spectrum resources and integration of next-generation satellites and terrestrial networks.