4G: LTE/LTE-Advanced for Mobile Broadband

Erik Dahlman, Stefan Parkvall, Johan Skold

• Publisher: Academic Press
• Year: 2013
• eBook ISBN: 9780124199972
• Edition: 2
• Topic: Technology & Engineering
• Subtopic: Mobile & Wireless Communications
• Index: Technology & Engineering

This book focuses on LTE with full updates including LTE-Advanced (Release-11) to provide a complete picture of the LTE system. Detailed explanations are given for the latest LTE standards for radio interface architecture, the physical layer, access procedures, broadcast, relaying, spectrum and RF characteristics, and system performance. Key technologies presented include multi-carrier transmission, advanced single-carrier transmission, advanced receivers, OFDM, MIMO and adaptive antenna solutions, radio resource management and protocols, and different radio network architectures. Their role and use in the context of mobile broadband access in general is explained, giving both a high-level overview and more detailed step-by-step explanations. This book is a must-have resource for engineers and other professionals in the telecommunications industry, working with cellular or wireless broadband technologies, giving an understanding of how to utilize the new technology in order to stay ahead of the competition. New to this edition: - In-depth description of CoMP and enhanced multi-antenna transmission including new reference-signal structures and feedback mechanisms - Detailed description of the support for heterogeneous deployments provided by the latest 3GPP release - Detailed description of new enhanced downlink control-channel structure (EPDDCH) - New RF configurations including operation in non-contiguous spectrum, multi-bands base stations and new frequency bands - Overview of 5G as a set of well-integrated radio-access technologies, including support for higher frequency bands and flexible spectrum management, massive antenna configurations, and ultra-dense deployments - Covers a complete update to the latest 3GPP Release-11 - Two new chapters on HetNet, covering small cells/heterogeneous deployments, and CoMP, including Inter-site coordination - Overview of current status of LTE release 12 including further enhancements of local-area, CoMP and multi-antenna transmission, Machine-type-communication, Device-to-device communication

Chapter 1

Background of LTE

Abstract

This chapter provides a historical overview of the evolution of mobile communication from the first generation of analog cellular systems, through second generation (2G) systems such as GSM and 3G systems including WCDMA/HSPA, into 4G LTE. ITU and its activities related to IMT and IMT-Advanced are described, as is the process in 3GPP, the organization responsible for developing the GSM, WCDMA/HSPA, and LTE technical specifications.

Keywords

3GPP; ITU; IMT; IMT-Advanced; standardization

1.1 Introduction

Mobile communication has become an everyday commodity. In the last decades, it has evolved from being an expensive technology for a few selected individuals to today’s ubiquitous systems used by a majority of the world’s population. From the first experiments with radio communication by Guglielmo Marconi in the 1890s, the road to truly mobile radio communication has been quite long. To understand the complex mobile-communication systems of today, it is important to understand where they came from and how cellular systems have evolved. The task of developing mobile technologies has also changed, from being a national or regional concern to becoming an increasingly complex task undertaken by global standards-developing organizations such as the Third Generation Partnership Project (3GPP) and involving thousands of people.

Mobile communication technologies are often divided into generations (see Figure 1.1), with 1G being the analog mobile radio systems of the 1980s, 2G the first digital mobile systems, and 3G the first mobile systems handling broadband data. The next generation, 4G or Long-Term Evolution (LTE), provides even better support for mobile broadband. Further evolution steps of 4G LTE will be taken within the next few years. In a longer term perspective, around 2020 one may enter into what some would call “5G” radio access, as discussed in Chapter 21. This continuing race of increasing sequence numbers for mobile system generations is in fact just a matter of labels. What is important is the actual system capabilities and how they have evolved, which is the topic of this chapter.

FIGURE 1.1 Generations of mobile communication systems

Later releases of LTE are sometimes known as LTE-Advanced, but it is important to point out that LTE and LTE-Advanced are the same technology. The label “Advanced” was primarily added to highlight the relationship between LTE release 10 (LTE-Advanced) and ITU/IMT-Advanced, as discussed later. This does not make LTE-Advanced a different system than LTE, and it is not in any way the final evolutionary step to be taken for LTE. Another important aspect is that the developmental work on LTE and LTE-Advanced is performed as a continuing task within 3GPP, the same forum that developed the first 3G system (WCDMA/HSPA). This book covers LTE and LTE-Advanced up to and including 3GPP release 11, with an outlook to what is expected in release 12 and future radio-access in general.

This chapter describes the background for the development of the LTE system in terms of events, activities, organizations and other factors that have played an important role. First, the technologies and mobile systems leading up to the starting point for 3G mobile systems will be discussed. Next, international activities in the ITU that were part of shaping 3G and the 3G evolution and the market and technology drivers behind LTE will be discussed. The final part of the chapter describes the standardization process that provided the detailed specification work leading to the LTE systems deployed and in operation today.

1.2 Evolution of mobile systems before LTE

The US Federal Communications Commission (FCC) approved the first commercial car-borne telephony service in 1946, operated by AT&T. In 1947 AT&T also introduced the cellular concept of reusing radio frequencies, which became fundamental to all subsequent mobile-communication systems. Similar systems were operated by several monopoly telephone administrations and wire-line operators during the 1950s and 1960s, using bulky and power-hungry equipment and providing car-borne services for a very limited number of users.

The big uptake of subscribers and usage came when mobile communication became an international concern involving several interested parties, in the beginning mainly the operators. The first international mobile communication systems were started in the early 1980s; the best-known ones are NMT that began in the Nordic countries, AMPS in North America, TACS in Europe, and J-TACS in Japan. Equipment was still bulky, mainly car-borne, and voice quality was often inconsistent, with “cross-talk” between users being a common problem. With NMT came the concept of “roaming,” providing a service for users traveling outside the area of their “home” operator. This also created a larger market for mobile phones, attracting more companies into the mobile-communication business.

The analog first-generation cellular systems supported “plain old telephony services” (POTS)—that is, voice with some related supplementary services. With the advent of digital communication during the 1980s, the opportunity to develop a second generation of mobile-communication standards and systems, based on digital technology, surfaced. With digital technology came an opportunity to increase the capacity of the systems, to give a more consistent quality of the service, and to develop much more attractive and truly mobile devices.

In Europe in the mid-1980s the GSM (originally Groupe Spécial Mobile, later Global System for Mobile Communications) project to develop a pan-European mobile-telephony system was initiated by the telecommunication administrations in CEPT¹ and later continued within the new European Telecommunication Standards Institute (ETSI). The GSM standard was based on Time-Division Multiple Access (TDMA), as were the US-TDMA standard and the Japanese PDC standard that were introduced in the same time frame. A somewhat later development of a Code-Division Multiple Access (CDMA) standard called IS-95 was completed in the USA in 1993.

All these standards were “narrowband” in the sense that they targeted “low-bandwidth” services such as voice. With the second-generation digital mobile communications came the opportunity to provide data services over the mobile-communication networks. The primary data services introduced in 2G were text messaging (Short Message Services, SMS) and circuit-switched data services enabling email and other data applications, initially at a modest peak data rate of 9.6 kbit/s. Higher data rates were introduced later in evolved 2G systems by assigning multiple time slots to a user and through modified coding schemes.

Packet data over cellular systems became a reality during the second half of the 1990s, with General Packet Radio Services (GPRS) introduced in GSM and packet data also added to other cellular technologies such as the Japanese PDC standard. These technologies are often referred to as 2.5G. The success of the wireless data service iMode in Japan, which included a complete “ecosystem” for service delivery, charging, etc. gave a very clear indication of the potential for applications over packet data in mobile systems, in spite of the fairly low data rates supported at the time.

With the advent of 3G and the higher-bandwidth radio interface of UTRA (Universal Terrestrial Radio Access) came possibilities for a range of new services that were only hinted at with 2G and 2.5G. The 3G/UTRA radio access development is today handled in 3GPP. However, the initial steps for 3G were taken in the early 1990s, long before 3GPP was formed.

What also set the stage for 3G was the internationalization of cellular standards. GSM was a pan-European project, but it quickly attracted worldwide interest when the GSM standard was deployed in a number of countries outside Europe. A global standard gains in economy of scale, since the market for products becomes larger. This has driven a much tighter international cooperation around 3G cellular technologies than for the earlier generations.

1.2.1 The first 3G standardization

Work on a third-generation mobile communication system started in ITU (International Telecommunication Union) in the 1980s, first under the label Future Public Land Mobile Telecommunications Systems (FPLMTS), later changed to IMT-2000 [1]. The World Administrative Radio Congress WARC-92 identified 230 MHz of spectrum for IMT-2000 on a worldwide basis. Of these 230 MHz, 2 × 60 MHz was identified as paired spectrum for FDD (Frequency-Division Duplex) and 35 MHz as unpaired spectrum for TDD (Time-Division Duplex), both for terrestrial use. Some spectrum was also set aside for satellite services. With that, the stage was set to specify IMT-2000.

In parallel with the widespread deployment and evolution of 2G mobile-communication systems during the 1990s, substantial efforts were put into 3G research activities worldwide. In Europe, a number of partially EU-funded projects resulted in a multiple access concept that included a Wideband CDMA component that was input to ETSI in 1996. In Japan, the Association of Radio Industries and Businesses (ARIB) was at the same time defining a 3G wireless communication technology based on Wideband CDMA, and in the USA a Wideband CDMA concept called WIMS was developed within the T1.P1² committee. South Korea also started work on Wideband CDMA at this time.

When the standardization activities for 3G started in ETSI in 1996, there were WCDMA concepts proposed both from a European research project (FRAMES) and from the ARIB standardization in Japan. The Wideband CDMA proposals from Europe and Japan were merged and came out as part of the winning concept in early 1998 in the European work on Universal Mobile Telecommunication Services (UMTS), which was the European name for 3G. Standardization of WCDMA continued in parallel in several standards groups until the end of 1998, when the Third Generation Partnership Project (3GPP) was formed by standards-developing organizations from all regions of the world. This solved the problem of trying to maintain parallel development of aligned specifications in multiple regions. The present organizational partners of 3GPP are ARIB (Japan), CCSA (China), ETSI (Europe), ATIS (USA), TTA (South Korea), and TTC (Japan).

At this time, when the standardization bodies were ready to put the details into the 3GPP specifications, work on 3G mobile systems had already been ongoing for some time in the international arena within the ITU-R. That work was influenced by and also provided a broader international framework for the standardization work in 3GPP.

1.3 ITU activities

1.3.1 IMT-2000 and IMT-Advanced

ITU-R Working Party 5D (WP5D) has the responsibility for IMT systems, which is the umbrella name for 3G (IMT-2000) and 4G (IMT-Advanced). WP5D does not write technical specifications for IMT, but has kept the roles of defining IMT in cooperation with the regional standardization bodies and maintaining a set of recommendations for IMT-2000 and IMT-Advanced. Recently, ITU-R has initiated an activity, sometimes referred to as IMT-2020, to look at the development of IMT technologies beyond what is defined for IMT-2000 and IMT-Advanced.

The main IMT-2000 recommendation is ITU-R M.1457 [2], which identifies the IMT-2000 radio interface specifications (RSPC). The recommendation contains a “family” of radio interfaces, all included on an equal basis. The family of six terrestrial radio interfaces is illustrated in Figure 1.2, which also shows the Standards Developing Organizations (SDO) or Partnership Projects that produce the specifications. In addition, there are several IMT-2000 satellite radio interfaces defin...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Preface
• Acknowledgments
• Abbreviations and Acronyms
• Chapter 1. Background of LTE
• Chapter 2. High Data Rates in Mobile Communication
• Chapter 3. OFDM Transmission
• Chapter 4. Wider-Band “Single-Carrier” Transmission
• Chapter 5. Multi-Antenna Techniques
• Chapter 6. Scheduling, Link Adaptation, and Hybrid ARQ
• Chapter 7. LTE Radio Access: An Overview
• Chapter 8. Radio-Interface Architecture
• Chapter 9. Physical Transmission Resources
• Chapter 10. Downlink Physical-Layer Processing
• Chapter 11. Uplink Physical-Layer Processing
• Chapter 12. Retransmission Protocols
• Chapter 13. Scheduling and Rate Adaptation
• Chapter 14. Access Procedures
• Chapter 15. Multi-Point Coordination and Transmission
• Chapter 16. Heterogeneous Deployments
• Chapter 17. Multimedia Broadcast/Multicast Services
• Chapter 18. Relaying
• Chapter 19. Spectrum and RF Characteristics
• Chapter 20. Performance
• Chapter 21. Future Radio Access—Final Thoughts
• References
• Index