A survey on space-aerial-terrestrial integrated 5G networks

Abstract

Thanks to their inherent advantages including large radio coverage and less dependence on terrestrial infrastructures, space and aerial networks can play an important role in 5G for ubiquitous coverage, large area broadcast services, and emergency communications. The space-aerial-terrestrial integrated networks (SATIN) are envisioned as an important trend of 5G evolution. However, due to distinct features including high altitude, moving platforms, large beam footprint and constrained payload, satellite networks are usually designed with unique protocols and functionalities, which hamper the integration of satellite networks with terrestrial mobile networks. The SATIN face many unprecedented technical challenges to achieve optimum performance, seamless user experience, and integrated security protection. This article makes a comprehensive overview of the latest researches from academia and industry to achieve the integrated 5G system. We first introduce the satellite and mobile technology trends, then present the vision of SATIN and related works in the area. Key enabling technologies from perspectives of the radio interface, networking, and security are discussed in depth. Then related standardization initiatives, especially the latest studies at 3GPP, and major industry research projects on non-terrestrial integrated 5G are reviewed. Important open issues are identified to inspire future studies for a fully integrated 5G system.