Contents Edited by: Ian C. Wong, Aditya Chopra, Sridhar Rajagopal, and Rittwik Jana; ISBN: 978-1-119-88601-3; September 2023; Wiley-IEEE Press; 240 Pages
Apart from 3GPP specifications for 5G and beyond, the Open RAN initiative has garnered tremendous excitement from the mobile industry. As a result, the O-RAN Alliance has emerged as the primary open RAN specification body, drawing contributions from major mobile operators and telco players. Leading mobile operators and equipment vendors are actively advocating for the deployment of O-RAN in the field, aiming to break free from vendor lock-in and unleash the full potential of AI-powered cloud-native RAN. The recently published book, “Open RAN: The Definitive Guide,” is a collaborative effort by a group of industry experts, addressing the timely need for a comprehensive understanding of the Open RAN movement, its current status, and future roadmaps.
Structured into 12 chapters, the book provides in-depth insights into various technical concepts related to Open RAN. It covers the overview of O-RAN architecture, explores various interfaces, highlights critical security aspects, discusses software development initiatives, and elucidates testing and integration activities. The content is presented in a clear and accessible manner, making it suitable for a broad audience of technical readers.
Chapter 1 opens with the functionalities of the key network components, the user equipment (UE), the radio access network (RAN), and the core networks (CN), of the mobile networks and specifically illustrates the evolution of the RAN over 2nd generations to the latest 5th generations (5G) of mobile networks. The opening chapter ends with a clear motivation for Open RAN.
Chapter 2 provides an overview of the Open RAN in the context of 5G and 6G use cases. Network programmability, virtualization, intelligence, and openness are presented as the salient features of O-RAN architecture. The author answers key questions about O-RAN initiatives in this chapter by mentioning the importance of O-RAN and the challenges it aims to over-come which help the readers appreciate the design choices of the O-RAN architectures.
Detailed architecture and various interfaces of O-RAN specifications are investigated in Chapter 3. Different O-RAN functions, RAN Intelligent Controllers (RIC) functions, Service Management and Orchestration (SMO) functions, their relationships with xApps and rApps, and the design principles of the interfaces are described in detail. App developers get a complete view of the O-RAN anatomy and key procedures to help design their xApp/rApp.
Chapter 4, discusses the virtualization and cloudification aspects of O-RAN vision. The impetus for Virtual RAN concepts gained traction with the availability of cost-effective Commercial Off-The-Shelf (COTS) hardware and O-RAN specifications that assure compatibility with various cloud and multi-cloud deployments. The journey of the RAN architecture from the traditional monolithic approach towards the latest containerized deployment strategy is depicted in this chapter with the necessary architectural transformation and adoption of cloud?native principles.
Chapter 5 articulates the necessity to use AI/ML algorithms to tackle the intractable problems of optimized RAN resource utilization based on interdependencies between the RAN parameters, user requirements, and performance KPIs across the network at scale. O-RAN is developed prioritizing AI-native and cloud-native approaches. In this chapter, the authors discussed O-RAN E2 service models to facilitate AI/ML life cycles and deployments for emerging use cases.
To complement the RAN functionality, efficient fronthaul and transport networks are essential in connecting a large number of radio cell sites. Chapter 6 and Chapter 7, shed light on the fronthaul interfaces and transport networks respectively. Important aspects like compression, massive MIMO, beam forming, and RAN-splits are discussed in the context of O-RAN in Chapter 6. Chapter 7 subsequently elaborates on the fronthaul, midhaul, and backhaul requirements, synchronization techniques, SDN-based transport networks, and their interactions with O-RAN management since O?RAN is conceived as an overlay on ton of the transport networks.
Chapter 8, introduces O-RAN security. Security best practices for xApp/rApp development, cloud deployment, potential threats from supply chains, vulnerable AI/ML models, and open interfaces are presented in this chapter.
In Chapter 9, the author presents the open-source initiatives around O-RAN software development. Overviews of Open Software Community RIC, the AI/ML Framework (AIMLFW), and Open Network Automation Platform (ONAP) projects are summarized with their various capabilities, compatibilities, and available supports.
Chapter-10, delves into the pragmatics of disaggregated, virtualized RAN deployments based on O?RAN principles. Practical decisions of RAN planning often include network function placements, capacity planning and dimensioning, hardware and software specifications, and requirement analysis for data center deployments. In this chapter, the authors consider deployments, monitoring, and management of O-RAN networks on cloud services such as AWS or GCP.
O-RAN specifies end-to-end testing of deployments focusing on functional testing, performance testing, services and security testing, load and stress testing, and RIC components testing. In Chapter 11, the author outlined the test and integration methodologies for the O-RAN ecosystem and how global initiatives such as O-RAN plug-fests, certification programs, and test specifications encourage the community to adopt O-RAN architecture in a robust way.
Finally, Chapter 12 summarizes multiple industry entities such as the Telecom Infra Project, The Small Cell Forums, and the 3GPP and their involvements to expedite the O-RAN movement.
This book explores O-RAN architectures, functions of O-RAN RIC/SMO and interfaces, key procedures, and deployment strategies in diverse cloud environments. The introduction of AI/ML-driven applications on O-RAN RICs accelerates the attainment of goals such as energy reduction in RAN, enhanced user experiences, and enablement of precise network resource management. This is achieved through the development of innovative xApps and rApps. Developers of xApps and rApps, as well as telecommunications professionals in general, can derive valuable insights from this book to better understand the intricacies of O-RAN specifications.