In 5G, non-terrestrial networks come in an array of connection scenarios, from satellite-based communications via airborne stations—e.g., air-to-ground or flight control of unmanned aerial vehicles (UAVs). This article gives a concise technology overview of the different network variations.
These include various satellite-based connectivity scenarios in which satellites differ in flying altitude and coverage area. To incorporate non-terrestrial networks (NTNs), 3GPP launched a Release 15 study [TR 38.811] on channel models and deployment scenarios. After completing this study, 3GPP followed up with a Release 16 study [TR 38.821] on solutions for adapting 5G NR to support NTNs. The main objective of this study is to identify a feature set that enables NTNs within the 5G system while minimizing the impact on the existing 5G system.