Terrestrial/Non-terrestrial Integrated Networks for Beyond 5G Communications

This chapter aims at providing an overview of the activities and goals of the Italian National project ITA NTN (Integrated Terrestrial and Non-Terrestrial Networks) that has been proposed and funded in the framework of the EU initiative defined as the Italian National Resilience and Restart Program. Therefore it presents an overview of the upcoming 6G-oriented scenario, where space network entities such as low-Earth orbit mega-constellations of nano-satellites, High-Altitude Platforms (HAP), and unmanned aerial vehicles (UAVS) cooperate with terrestrial networks to provide a 3-dimensional (3D) wireless connectivity. Moreover, the evolution from interoperable to fully integrated scenarios is summarized and discussed together with the description of the future architectures and a brief overview of the 3GPP technical specifications about terrestrial and non-terrestrial systems and subnetworks. Finally, the project vision and the envisaged road map are presented.