¿ This updated book, reconfigured as a textbook, covers the key technologies associated with the physical transmission of data on 5G mobile systems. Following an updated overview of these technologies, the author provides a high-level description of 3GPP's mobile communications standard (5G NR) and shows how the key technologies presented earlier facilitate the transmission of very high-speed user data and control data and can provide very low latency for use cases where this is important. In the final chapter, an overview and the physical layer aspects of 5G NR enabled Fixed Wireless Access (FWA) networks is presented. Material in the first edition addressed mainly the key physical layer technologies and features associated with 3GPP release 15, the first release to support 5G. This edition adds descriptions of some of the technological advancements supported in release 16, including integrated access and backhaul (IAB), sidelink communication, NR positioning, operation in unlicensed bands, and multiple transmission points transmission. This textbook is intended for graduate and upper undergraduate engineering students and practicing engineers who have an interest in 3GPP's 5G enabled mobile and or FWA networks and want to acquire, where missing, the necessary technology background in order to understand 3GPP's physical layer specifications and operation. The author provides working problems and helpful examples throughout the text.