Non-Terrestrial Networks: An Overview of 3GPP Release 17 & 18.

This article provides an overview of technological advancements in Non-Terrestrial Networks (NTN) from the perspective of the 3 ^rd Generation Partnership Project (3GPP). With the introduction of 3GPP Release 17 & 18, there has been a significant emphasis on integrating satellite access networks into terrestrial networks. This integration necessitates a holistic design approach that spans multiple areas, including the Radio Access Network (RAN) to services and system aspects to core, and terminals. The article provides insights and implications of incorporating satellite access networks as a new 3GPP RAN and as a backhaul solution. We explore the impact of this integration on network architecture and performance, considering factors such as coverage, capacity, and latency. The article also highlights the key issues in 3GPP Release 18 and outlines the prospective potential solutions in the context of NTN to support 5G and beyond integrated architecture. Additionally, the article discusses the enhancements made in 3GPP Release 18 to support 5G and beyond in the context of Uncrewed Aerial Vehicles (UAVs).