中文译名：5G NR标准:下一代无线通信技术LTE已成为迄今为止全球最成功的、服务于数十亿用户的移动宽带技术。毫无疑问，移动宽带现在是，将来也是移动通信的重要组成部分，但未来的无线网络在很大程度上将涵盖更广泛的应用和更广阔的需求。虽然LTE是一项非常强大的技术并且仍在不断发展，在未来许多年内仍将被继续使用，但是新的5G无线接入技术——（New Radio，新空口）——已经被标准化，以满足未来的需求。本书对NR标准进行了描述。NR标准是在2018年春末由3GPP制定的新一代无线接入技术标准。第1章对5G做了简单介绍。第2章描述了标准化的过程和相关的组织，比如3GPP和ITU。第3章介绍了可用于移动通信的频段以及发掘可用新频段的流程。有关LTE及其演进的概述请参阅第4章。虽然本书的重点是NR，但作为后续章节的背景，对LTE做简要概述是有益的。一个原因是，LTE和NR都是由3GPP制定的，因此具有共同的背景，并且使用了某些相同的技术构件。NR中的许多设计选择也是基于LTE的经验做出的。此外，LTE还会继续与NR并行发展，仍是5G无线接入中的重要组成部分。第5章是对NR的概述，可以单独阅读以获得对NR的宏观理解，也可以作为对后续章节的介绍。第6章概述了NR总的协议结构，第7章描述了NR整个的时频域结构。多天线处理和波束赋形是NR的重要组成部分。第8章概述了支持这些功能的信道探测方法，第9章总体介绍了传输信道的处理，第10章介绍了相关的控制信令。这些功能如何支持不同的多天线方案和波束赋形在第11章和第12章中描述。重传功能和调度是第13章和第14章的主题，第15章讲功率控制，第16章讲初始接入。与LTE的共存和互通是NR的重要组成部分，特别是在依赖LTE进行移动性和初始接入的非独立组网模式下。第17章对此进行了介绍。考虑到大频率范围上以及多标准无线终端的频谱灵活性，第18章描述了NR对射频的要求。第19章讨论了毫米波范围内较高频段的射频实现所要考虑的问题。最后，第20章对本书做了总结，对未来的NR版本进行了展望。Long-Term Evolution (LTE) has become the most successful wireless mobile broadband technology across the world, serving billions of users. Mobile broadband is, and will continue to be, an important part of future cellular communication, but future wireless networks are to a large extent also about a significantly wider range of use cases and a correspondingly wider range of requirements. Although LTE is a very capable technology, still evolving and expected to be used for many years to come, a new 5G radio access known as New Radio (NR) has been standardized to meet future requirements.This book describes NR, developed in 3GPP (Third Generation Partnership Project) as of late Spring 2018.Chapter 1 provides a brief introduction, followed by a description of the standardization process and relevant organizations such as the aforementioned 3GPP and ITU in Chapter 2. The frequency bands available for mobile communication are covered in Chapter 3 together with a discussion on the process for finding new frequency bands.An overview of LTE and its evolution is found in Chapter 4. Although the focus of the book is NR, a brief overview of LTE as a background to the coming chapters is relevant. One reason is that both LTE and NR are developed by 3GPP and hence have a common background and share several technology components. Many of the design choices in NR are also based on experience from LTE. Furthermore, LTE continues to evolve in parallel with NR and is an important component in 5G radio access.Chapter 5 provides an overview of NR. It can be read on its own to get a high-level understanding of NR, or as an introduction to the subsequent chapters.Chapter 6 outlines the overall protocol structure in NR, followed by a description of the overall timefrequency structure of NR in Chapter 7.Multiantenna processing and beam-forming are integral parts of NR. The channel sounding tools to support these functions are outlined in Chapter 8, followed by the overall transport-channel processing in Chapter 9 and the associated control signaling in Chapter 10. How the functions are used to support different multi-antenna schemes and beamforming functions is the topic of Chapters 11 and 12.Retransmission functionality and scheduling are the topics of Chapters 13 and 14, followed by power control in Chapter 15 and initial access in Chapter 16.Coexistence and interworking with LTE is an essential part of NR, especially in the nonstandalone version which relies on LTE for mobility and initial access, and is covered in Chapter 17.Radio-frequency (RF) requirements, taking into account spectrum flexibility across large frequency ranges and multistandard radio equipment, are the topic of Chapter 18. Chapter 19 discusses the RF implementation aspects for higher frequency bands in the mm-wave range.Finally, Chapter 20 concludes the book with an outlook to future NR releases.