Shaping Future 6G Networks. Группа авторов

1.3 Book Outline and Main Topics

      1.3.1 Use Cases and Requirements for 6G (Chapter 2)

      The first point we address in the following chapters concerns the prospective services and use cases that could require a new generation of mobile communication networks. For defining 5G, enterprise needs – rather than the consumer market – have been the main driver. By the way, the rise of private 5G is a good illustration of the growing importance of the business‐to‐business (B2B) market for mobile networks. We believe these B2B needs will also be the primary driver for the evolution of 5G and the definition of 6G. Innovation in mobile networking will be pushed more and more by companies for their own needs, either by using carrier networks (e.g. with slicing solutions) or through innovative private 5G deployments. In Chapter 2, the authors introduce a collection of potential 6G services for the B2B market, in order to understand potential 6G drivers and the associated requirements. Authors consider services in eight different application domains: digital transformation of manufacturing, teleporting with holography, digital twin, smart transportation, public safety, health and well‐being, smart IoT for life quality improvement, and transformation of the financial sector. The authors then derive the key networking requirements induced by these services.

      1.3.2 Standardization Processes for 6G (Chapter 3)

      The second question we investigate is how and by whom can 6G be defined. Previous generations have been framed under the leadership of the telco industry grouped in standardization bodies (e.g. 3GPP). However, new bodies are emerging, for example, with the OpenRAN alliance to improve openness in radio access networks of next generation wireless systems. De facto standards are more and more driven by providing software implementation within open‐source communities, rather than by submitting written contributions to international standardization bodies. New actors are also emerging alongside the telco industry (e.g. Facebook with Magma), which is being reduced more and more to a few suppliers, and industry verticals are more frequently pushing their own needs and solutions (e.g. 5G Alliance for Connected Industries and Automation [5G‐ACIA]). In Chapter 3, authors investigate this evolving role of standards for 6G. They also discuss the impact of the shift started in 5G from a standardization based on functional entities to a standardization based on Application Programming Interface (API). Finally, they raise the question of economic as well as political pressures on industry players that might lead to a fragmented ecosystem.

      1.3.3 Energy Consumption and Social Acceptance (Chapters 4 and 5)

Lower energy consumption was already an important design criterion in the course of 5G research and development. But with climate change progressing, this requirement is becoming even more important for the design of 6G. Thus, another question to address is the environmental sustainability of 6G. We discuss this topic in two different chapters, showing two complementary viewpoints. In Chapter 4, authors look at technical solutions to provide more sustainable cellular networks, relying on an intensive use of AI mechanisms. First, they identify the main factors of energy consumption in mobile networks. They then provide a holistic approach for defining a more sustainable 6G based on AI training executed at the edge of the network. Authors of Chapter 5 argue that reducing network energy consumption per byte transferred is not a sufficient path when the bandwidth consumption is continuously increasing (rebound effect). The question of sustainability is therefore not only a technical question but also a social and societal issue. Here, marketing will be an important point, along with consumers’ rising awareness of the impact of information technologies on global warming. Beside the eco‐design of networks and services, the question of changing the way we consume network and service offers should be addressed, with a possible trend toward more digital sobriety.

      1.3.4 New Technologies for Radio Access (Chapters 6–8)

      Every new mobile generation features a new radio technology, which typically pushes for higher frequencies and, thanks to new coding and signal processing algorithms, enables much higher data rates and communication capacities to mobile users. In city centers, the deployment of new antenna systems for ever smaller cell sizes operating in ever higher frequencies is facing limitations with signal distribution through walls and windows, representing big challenges. Chapter 6 provides an overview of the development of new reflective materials to enhance coverage of urban areas, introducing the technology and the challenges of reconfigurable intelligent surfaces (RIS) for smart radio environments.

      In 6G, terahertz (THz) communications represent this next big radio access network innovation. Chapter 6 describes the new technical capabilities and the research challenges to be mastered to exploit these capabilities. In particular, THz base stations will enable the seamless integration of sensing, localization, and communications, making new types of applications possible. At the same time, they put immense requirements on the core network to utilize these new capabilities.

      While THz access networks feature small cell sizes and are likely used for indoor use cases, satellite networks have already gained momentum in the context of 5G evolution for outdoor coverage in rural environments, the maritime environment, and the sky. Besides satellites at different orbit levels, drones and high‐altitude platforms have also emerged as so‐called non‐terrestrial networks in the recent past. The authors of Chapter 8 address opportunities and technical challenges to master the upcoming 6G network architectures, including the need for new mechanisms for dynamic access and backhaul network integration, as well as challenges in roaming and handovers in between moving cells and networks.

      1.3.5 New Technologies for Network Infrastructure (Chapters 9 and 10)

Beside the radio technologies, a new mobile network generation is also an opportunity to reframe the underlying mechanisms of access and core networks. Chapters 9 and 10 discuss new requirements to address by the network infrastructure (especially on the routing layer), as well as the various solutions to progress on a more optimized implementation. First, one of the major drivers and the foundation for network convergence, the Internet Protocol (IP) also represents a major legacy and limitation factor in communications. The design of 6G is also an opportunity to question this foundational layer 3 protocol, as has already been done for other layers (e.g. Quick UDP Internet Connections [QUIC] for layer 4), in order to solve some intrinsic limits, such as addressing scheme or security vulnerabilities. In Chapter 9, authors investigate options to renovate basic low‐level communication protocols to gain more efficiencies and flexibilities beyond the limits of the IP framework. Starting from some iconic application domains (e.g. holographic communication, Industry 4.0), they introduce future requirements for this new framework: high‐precision and deterministic services with the right quality of service (QoS) level, user‐defined network operations embedded in the packet delivery layer, semantic and flexible addressing, optimal support of various types of access technologies with a high throughput, and intrinsic