Y.-P. Eric Wang

Radio access for ultra-reliable and low-latency 5G communications

Fifth generation wireless networks are currently being developed to handle a wide range of new use cases. One important emerging area is ultra-reliable communication with guaranteed low latencies well beyond what current wireless technologies can provide. In this paper, we explore the viability of using wireless communication for low-latency, high-reliability communication in an example scenario of factory automation, and outline important design choices for such a system. We show that it is possible to achieve very low error rates and latencies over a radio channel, also when considering fast fading signal and interference, channel estimation errors, and antenna correlation. The most important tool to ensure high reliability is diversity, and low latency is achieved by using short transmission intervals without retransmissions, which, however, introduces a natural restriction on coverage area.

Analysis of ultra-reliable and low-latency 5G communication for a factory automation use case

The fifth generation (5G) of cellular networks is starting to be defined to meet the wireless connectivity demands for 2020 and beyond. One area that is considered increasingly important is the capability to provide ultra-reliable and low-latency communication, to enable e.g., new mission-critical machine-type communication use cases. One such example with extremely demanding requirements is the industrial automation with a need for ultra-low latency with a high degree of determinism. In this paper, we discuss the feasibility, requirements and design challenges of an OFDM based 5G radio interface that is suitable for mission-critical MTC. The discussion is further accompanied with system-level performance evaluations that are carried out for a factory hall-wide automation scenario with two different floor layouts.

Chapter 1 – The Cellular Internet of Things

This chapter introduces the overall content of the book. It contains a brief introduction to the massive Machine-Type Communications (mMTC) category of use cases, spanning a wide range of applications such as smart metering and wearables. When discussing these applications, special attention is given to the service requirements associated with mMTC, for example, in terms of reachability, throughput, and latency. The chapter continues and introduces the concept of the Cellular Internet of Things (CIoT) and the three technologies Extended Coverage Global System for Mobile Communications Internet of Things (EC-GSM-IoT), Narrowband Internet of Things (NB-IoT), and Long-Term Evolution for Machine-Type Communications (LTE-M) that can be said to define this concept. While EC-GSM-IoT and LTE-M are backward compatible solutions based on GSM and LTE, respectively, NB-IoT is a brand new radio access technology. The final part of the chapter looks beyond the set of cellular access technologies and introduces the Low Power Wide Area Network (LPWAN) range of solutions that already have secured a significant footprint in the mMTC market. Unlike the cellular systems, these LPWANs have been designed to operate in licensed exempt spectrum. An initial discussion around the pros and cons of licensed exempt operation is presented to prepare the reader for the final chapters of the book, where a closer look is taken at operation in the unlicensed frequency domain.

NB-IoT Performance

This chapter presents the Narrowband Internet of Things (NB-IoT) performance in terms of coverage, data rate, latency, battery lifetime, and system capacity. All these performance aspects differ between the three operation modes of NB-IoT. Thus, in most cases the performance of each NB-IoT operation mode is individually presented. It shows that all the three operation modes of NB-IoT meet the Third Generation Partnership Project (3GPP) performance objectives agreed for Cellular IoT.

Chapter 10 – 5G and the Internet of Things

This chapter describes the evolution of mobile networks toward 5G. Beyond an evolution of the mobile broadband experience, 5G will provide optimized connectivity for MTC and IoT services. An overview of the standardization activities toward massive Machine-Type Communications (mMTC), as well as critical Machine-Type Communications (cMTC), with Ultra Reliable and Low Latency Communications (URLLC) is presented.

EC-GSM-IoT

Abstract This chapter presents the design of Extended Coverage Global System for Mobile Communications Internet of Things (EC-GSM-IoT). The initial section describes the background of the GSM radio access technology, highlighting the suitability of an evolved GSM design to support the Cellular IoT (CIoT) core requirements, which includes ubiquitous coverage, ultra-low-device cost, and energy efficient device operation. The following sections builds from the ground up, starting with the physical layer, going through fundamental design choices such as frame structure, modulation, and channel coding. After the physical layer is covered, the basic procedures for support of full system operation are covered, including, for example, system access, paging functionality, and for EC-GSM-IoT-improved security protocols. The reader will not only have a good knowledge of EC-GSM-IoT after reading the chapter but will also have a basic understanding of what characteristics a system developed for CIoT should possess. At the end, a look at the latest enhancements of the EC-GSM-IoT design is presented.

Chapter 6 – LTE-M Performance

Abstract This chapter presents Long-Term Evolution for Machine-Type Communications (LTE-M) performance in terms of coverage, data rate, latency, and system capacity based on the 3GPP Release 13 functionality described in Chapter 5 . The methods and assumptions are to a large extent following those used for Extended Coverage Global System for Mobile Communications Internet of Things (EC-GSM-IoT) and Narrowband-IoT (NB-IoT) performance evaluations as described in Chapters 4 and 8 Chapter 4 Chapter 8 . When there are differences, those are explicitly described in this chapter. The reduction in device complexity achieved by LTE-M compared to earlier 3GPP releases of LTE is also presented. While LTE-M has been specified for both half-duplex frequency-division duplexing (HD-FDD) and full duplex FDD (FD-FDD) operation as well as time-division duplexing (TDD) operation, this chapter focuses on the performance achievable for LTE-M in HD-FDD operation.