 Department of Computer Science, University of Wolverhampton, Wolverhampton, UK I. Picallo Electric, Electronic and Communication Engineering Department, Public University of Navarra, Pamplona, Navarra, Spain P. Reungoat Altran ACS, Saint-Herblain, France P. Shaik Department of Electrical Engineering, IIT, Indore, India E. Sharma Indian Institute of Technology, Roorkee, India Editor and Contributors P. Singh International institute of Information Technology, Bangalore, India P. Swami Indian Institute of Technology Indore, Indore, Madhya Pradesh, India C. Vargas-Rosales School of Engineering and Sciences, Tecnologico de Monterrey, Monterrey, NL., Mexico Chapter 1 A Comprehensive Study on 5G: Check for updates RAN Architecture, Enabling Technologies, Challenges, and Deployment Mohammed Alfaqawi, Martine Gateau, Patrick Huard, Pascal Reungoat, Marie-Christine Le Mercier, Stéphane Davai, and Mouna Ben Mabrouk 1.1 Introduction Different from its predecessors, the 5G eco-system has been developed not only to enable human-to-human (H2H) communication but also to provide services for human-to-machine (H2M) and machine-to-machine (M2M) communications. In order to fulfill the diverse requirements of the vast and wide-scale applications of mobile network operators (MNOs), vertical industries, and third-party tenants, 5G is targeting three main families of use cases (UCs): (1) enhanced mobile broadband (eMBB) for the classical applications of H2H communication with data rate up to 10-20 Gbps, (2) massive machine-type communication (mMTC) to provide services for 100 billion end-user devices with density of 106 devices/km2 and stringent requirements on energy consumption, and (3) ultra-reliable low latency communication (URLLC) for critical and delay-sensitive applications. These three UCs can be considered as an umbrella that covers a myriad of applications with varying requirements such as tactile Internet, video gaming and streaming, virtual/augmented reality (VR/AR), autonomous cars, smart transportation, smart agriculture