volution beyond Release-15, describing technologies introduced in Release-16: e.g. relaying, also known as integrated access and backhaul (IAB, and satellite access, also known as non-terrestrial networks. Chapter 6 ("Enabling technologies") is dedicated to various technologies that are not always considered part of RAN architecture but are nevertheless fundamental to RAN deployments. These include implementation-related aspects, such as virtualization and open source, edge computing, Operations, Administration, and Maintenance (OAM), and last but not least the transport network technologies. We finish the book with Chapter 7 ("NG-RAN Deployment Considerations") by dis- cussing the practical implications of selecting the right RAN architecture and deploying it to serve the practical needs of an operator. A note on terminology: throughout this book, we generally try to use a consistent termi- nology. However, that is not always possible, or convenient - in particular, because similar technologies may sometimes be commonly referred to by different names in different stan- dards, industries, or literature. As this book crosses multiple domains, it is challenging to use a uniform terminology, which is at the same time consistent with different terminolo- gies used in their respective fields. One such example is the term "5G" itself-while - it is used extensively in technical literature, marketing materials, product descriptions, etc. - many (but not all) 3GPP specifications intentionally avoid the term, using terminology such as New Radio (NR) when referring to the air interface and NG-RAN (which is not an acronym at all, but is considered a "monolithic term") when referring to the RAN. Another example is the network interface between the NG-RAN and the core network, which is referred to as the NG interface in RAN specifications and N2/N3 reference points in core network stan- dards. We therefore took the pragmatic approach of using common terminology where we felt it is appropriate, and otherwise using the terminolo