Preface

The rollout of Long Term Evolution-Advanced (LTE-A) as the fourth generation of mobile communications brought mobile systems to unprecedented throughput of more than 600 Mbps. Therefore, the fifth-generation (5G) of mobile communications had to go beyond the objective of the realization of more transmission capacity. Indeed, 5G targeted the fulfillment of the communications requirements of different vertical application fields. The realized performance covers three-dimensional space, namely, (1) enhanced mobile broadband (eMBB) for bandwidth-hungry applications such augmented reality/virtual reality (AR/VR); (2) ultra-reliable low-latency communication (URLLC) for use cases with high sensitivity to delay like in vehicle-to-vehicle (V2V) or vehicle-to-infrastructure (V2I) applications; and (3) massive Internet-of-Things (IoT). To achieve high performance, 5G relies on several enhanced technologies, which have already shown their potential with LTE-A (4G) and LTE-A Pro (4.5), such as multi-input multi-output (MIMO), spectrum flexibility, higher spectral efficiency, machineto-machine communication/ machine-type communications (M2M / MTC), and so on. Furthermore, 5G exploits the advantages of softwarization techniques using fog computing, cloud computing, artificial intelligence (AI), machine learning (ML), and more. This book discusses some of these softwarization techniques and some practical aspects from the 5G deployment scenarios. This book is a reference to mobile broadband networks as well as practical use cases of wireless broadband communications. Committed to bridging the gap between theory and practice, this book is also a concise guide for graduate students and readers interested in studying next-generation mobile networks (NGMN) and concepts/applications of mobile communications engineering.

Section 1, "System Realization and Enabling Technologies," presents different computing-based paradigms such as cloud computing and fog computing in the context of 5G. Chapter 1, "Trends in Cloud Computing Paradigms: Fundamental Issues, Recent Advances, and Research Directions toward 6G Fog Networks," presents a comprehensive review of these architectures and their associated concepts. The chapter also discusses beyond 5G (B5G/6G) perspectives. Chapter 2, "Low-Latency Strategies for Service Migration in Fog Computing Enabled Cellular Networks," presents the concepts of fog computing-enabled cellular networks (FeCN), in which computing, storage, and network functions are provisioned closer to the end-users, thus the latency on transport networks can be reduced significantly. In the context of FeCN, the high mobility feature of users brings critical challenges to maintain service continuity with stringent service requirements. Service migration, referred to as transmitting the associated services from the current fog server to the target one, has been regarded as a promising solution to fulfill service continuity during mobility. Chapter 3, "Artificial Intelligence and Machine Learning in 5G and beyond: A Survey and Perspectives," describes the role of AI and ML in 5G and beyond, to build cost-effective and adaptable performing, next-generation mobile networks. The chapter also presents some practical use cases of AI/ML in a network life cycle. The last chapter of this section, "A Brief Overview of CRC Implementation for 5G NR," gives an overview of the cyclic redundancy check (CRC) implementation in 5G New Radio (NR).

It is obvious that the future mobile communications systems will be increasingly complex and heterogeneous, with different networking technologies. Therefore, Section 2, "Practical Aspects from Next Generation Mobile Landscape," presents three use-case scenarios. In chapter 5, "Prospects of 5G Satellite Networks Development," the authors discuss the spectral and technological aspects of 5G satellite networks developments, issues of architecture and role of delays on quality of services of 5G satellite segments, and the possibility of constructing a 5G satellite segment based on distributed and centralized gNB base stations. It also considers issues of satellite payload utilization for bent-pipe and onboard processing technologies in 5G satellite segments. Chapter 6, "An LTE-Direct-Based Communication System for Safety Services in Vehicular Networks," presents a cluster-based LTE sidelink-based V2V multicast/broadcast architecture to satisfy the latency and reliability requirements of V2V safety applications. This architecture combines a new Proximity Service (ProSe) discovery mechanism for sidelink peer discovery and a cluster-based, round-robin scheduling technique to distribute the sidelink radio resources among the cluster members. The last chapter, "Healthcare Application-Oriented Non-Lambertian Optical Wireless Communications for B5G&6G," introduces the healthcare application of optical wireless communication (OWC) based on non-Lambertian beams, and analyzes different application scenarios of OWC based on Unmanned Aerial Vehicles (UAVs), high-speed trains (HST), and unmanned underwater vehicles (UUVs). Finally, it presents research prospects of OWC in B5G and 6G.

To conclude, the editor is grateful to all colleagues who authored the chapters of this book and contributed with valuable references and interesting results related to their current research and applications. We are also grateful to the members of the support team at IntechOpen for their help and professionalism. Special thanks are due to the reviewers for their willingness to review the chapters and provide useful feedback to the authors. We would particularly like to thank our colleague Abdelhak Aqqal for his thorough feedback in order to improve the quality of the publication.

> **Abdelfatteh Haidine** Laboratory of Information Technologies, National School of Applied Sciences, Chouaib Doukkali University,

> > El Jadida, Morocco

Section 1

System Realization and

Enabling Technologies

Section 1
