3/4: Non-Terrestrial Networks (NTN): Fundamentals, Standards, Performance, and Practice

The continuous evolution of 5G technology aims to improve performance and addresses new use cases. Enabling 5G system to support non-terrestrial networks (NTNs) has been one direction under exploration in 3GPP. NTN has become an umbrella term for any network that involves flying objects, including satellite communication networks, high altitude platform systems, and air-to-ground networks. The inherent flexibility of 5G technology provides a solid foundation for adapting it to support NTNs. However, NTNs are complex systems, the design of which requires a holistic approach. The objective of this tutorial is to offer a comprehensive learning experience about the state-of-the-art research and development in NTNs. We will describe the fundamentals of NTNs, explain in detail the design aspects, provide an overview of the latest standardization development of NTNs in 3GPP, share design rationales influencing standardization, presenting system performance evaluation methodology and the latest results, delivering practical, current information on the best industry practices, and pointing out fruitful avenues for future research.