Mobile and Wireless Communications for IMT-Advanced and Beyond

By Afif Osseiran

A timely addition to the understanding of IMT-Advanced, this book places particular emphasis on the new areas which IMT-Advanced technologies rely on compared with their predecessors. These latest areas include Radio Resource Management, Carrier Aggregation, improved MIMO support and Relaying.

Each technique is thoroughly described and illustrated before being surveyed in context of the LTE-Advanced standards. The book also presents state-of-the-art information on the different aspects of the work of standardization bodies (such as 3GPP and IEEE), making global links between them.

• Explores the latest research innovations to assess the future of the LTE standard
• Covers the latest research techniques for beyond IMT-Advanced such as Coordinated multi-point systems (CoMP), Network Coding, Device-to-Device and Spectrum Sharing
• Contains key information for researchers from academia and industry, engineers, regulators and decision makers working on LTE-Advanced and beyond

• Language: English
• Publisher: Wiley
• Release date: Aug 8, 2011
• ISBN: 9781119977490

Book preview

To those who Believe and Strive for a Just and Ethical World.

In memory of Mohamad Bouazizi

A. Osseiran

To my other half, Lorena, and the fruit of our love, Mireia.

Welcome to the world honey

J. F. Monserrat

To my parents

W. Mohr

About the Editors

Afif Osseiran

Dr. Osseiran received a B.Sc. in Electrical Engineering from Université de Rennes I, France, in 1995, and a DEA (B.Sc.E.E) degree in Electrical Engineering from Université de Rennes I and INSA Rennes in 1997, and a M.A.Sc. degree in Electrical and Communication Engineering from École Polytechnique de Montréal, Canada, in 1999. In 2006, he successfully defended his Ph.D thesis at the Royal Institute of Technology (KTH), Stockholm, Sweden. Since 1999 he has been with Ericsson, Sweden. In 2004 he joined as one of Ericsson's representatives the European project WINNER. During the years 2006 and 2007 he led in WINNER the spatial temporal processing (i.e. MIMO) task. From April 2008 to June 2010, he was the technical manager of the Eureka Celtic project WINNER+. His research interests include many aspects of wireless communications with a special emphasis on advanced antenna systems, on relaying, on radio resource management, network coding and cooperative communications. Dr. Osseiran is listed in Who's Who in the World and Who's Who in Science and Engineering. He has published more than 40 technical papers in international journals and conferences. In 2009, Dr. Osseiran coauthored Radio Technologies and Concepts for IMT-Advanced with John Wiley & Sons. Since 2006, he has been teaching advanced antennas at Master's level at the Royal Institute of Technology (KTH) in Stockholm.

Jose F. Monserrat

Dr. Monserrat received his MSc. degree with High Honors and Ph.D. degree in Telecommunications Engineering from the Polytechnic University of Valencia (UPV) in 2003 and 2007, respectively. He was the recipient of the First Regional Prize of Engineering Studies in 2003 for his outstanding student record, also receiving the Best Thesis Prize from the UPV in 2008. In 2009 he was awarded with the Best Young Researcher prize in Valencia. He is currently an associate professor in the Communications Department of the UPV. His research focuses on the application of complex computation techniques to Radio Resource Management (RRM) strategies and to the optimization of current and future mobile communications networks, such as LTE-Advanced and IEEE 802.16m. He has been involved in several European Projects, acting as task or work package leader in WINNER+, ICARUS, COMIC and PROSIMOS. In 2010 he also participated in an external evaluation group within ITU-R on the performance assessment of candidates for the future family of standards, IMT-Advanced.

Werner Mohr

Dr. Mohr graduated from the University of Hannover, Germany, with a Masters degree in Electrical Engineering in 1981 and a Ph.D. degree in 1987. He joined Siemens AG, Mobile Network Division, Munich, Germany, in 1991. He was involved in several EU-funded projects and ETSI standardization groups on UMTS and systems beyond 3G. In December 1996 he became project manager of the European ACTS FRAMES Project until the project finished in August 1999. This project developed the basic concepts for the UMTS radio interface. Since April 2007 he has been with Nokia Siemens Networks GmbH & Co. KG, Munich, Germany, where he is Head of Research Alliances. He was the coordinator of the WINNER Project in Framework Program 6 of the European Commission, Chairman of WWI (Wireless World Initiative) and the Eureka Celtic project WINNER+. The WINNER project laid the foundation for the radio interface for IMT-Advanced and provided the starting point for the 3GPP LTE standardization. He was also Vice Chair of the eMobility European Technology Platform in the period 2008–9 and is now eMobility (now called Net!Works) Chairperson for the period 2010–2011. He was Chair of the Wireless World Research Forum from its launch in August 2001 up to December 2003. He is a member of VDE (Association for Electrical, Electronic and Information Technologies, Germany) and Senior Member of IEEE. In 1990 he received the Award of the ITG (Information Technology Society) in VDE. He was a board member of ITG in VDE for the term 2006–8 and was re-elected for the 2009–11 term. He is coauthor of the books Third Generation Mobile Communication Systems and Radio Technologies and Concepts for IMT-Advanced.

Preface

Goal and Objective of the Book

This book was prompted by the desire to fill the gap between theoretical descriptions and a more pedagogical description of the main technological components of International Mobile Telecommunications Advanced (IMT-Advanced) such as Radio Resource Management (RRM), Carrier Aggregation (CA), improved MIMO support, and relaying. The book also covers the latest research innovations beyond the IMT-Advanced system, in particular, promising areas such as Coordinated Multipoint transmission or reception (CoMP), Network Coding (NC), Device-to-Device (D2D) and spectrum sharing.

Each chapter presents the basis of its topic in a simple way. A review of the latest research advances for that topic is then given. A special emphasis in each area is given to the state of the art of global standardization, in particular LTE-A. Finally, each chapter concludes by looking towards the future and discussing predictions. The reader is expected to have completed a basic undergraduate course in digital communications and mathematics (i.e. probability, calculus and linear algebra).

In order to help the reader extract the important information, the most relevant statements in every chapter are framed in a gray color, or emphasized in italic.

Structure of the Book

Chapter 1 provides an overview of cellular technology evolution and the latest market and technology trends. Chapter 2 presents innovative concepts for advanced RRM. Carrier Aggregation techniques are presented in Chapter 3. Chapter 4 explains spectrum sharing, especially within the context of femtocell, and game theory. Multiple-Input Multiple-Output (MIMO), and in particular Multi-User (MU)-MIMO are treated in Chapter 5. Chapter 6 thoroughly describes CoMP. Relaying for IMT-Advanced is addressed in Chapter 7. Chapters 8 and 9 address beyond IMT-Advanced areas, Network Coding and Device-to-Device communications, respectively. In Chapter 10 the end-to-end performance of LTE-Advanced (LTE-A) candidates is carefully presented. Chapter 11 discusses the future research trends within wireless communications. The appendices contain additional information related to Chapters 2, 3, 6, 8 and 10.

Background

Writing a book is a long journey involving substantial effort from a group of people. The core contributors of this book are from the alumni of the WINNER(+) project, which for more than six years provided an extraordinary forum for collaboration and contribution to global fora such as the Third Generation Partnership Project (3GPP) and the International Telecommunication Union (ITU). In 2004 the project paved the way toward InternationalMobile Telecommunications Advanced.

The WINNER project was a six-and-a-half year journey. It started with WINNER-I the first phase in 2004, continued with the second phase, WINNER-II (through years 2006-7), and was finalized in WINNER+ (2008-mid-2010). These successful achievements were possible due to the close cooperation of project partners, respecting the interests of the different organizations. It was an excellent experience to cooperate in such an environment, where problems were analyzed and discussed in a trustful manner, blessed with consensus.

Finally, the editors would welcome any comments and suggestions for improvements or changes. They can be reached at the following e-mail address: [e-mail].

Acknowledgements

Only part of the material in this book has been extracted from or based on several of the public deliverables of the European Celtic project WINNER+. The completion of this project was supported by substantial additional material, which was originally not planned in the consortium. We would therefore like to thank all the colleagues involved in the project for their support and the good cooperation that made the book possible.

We aremost grateful to the co-authors of this manuscript. They have shown incredible commitment and dedication during the writing process. Many were working in their free time, during evenings and week-ends. They have demonstrated an exemplary spirit of collaboration, always being available while dealing with professional and private constraints. During the period in which the book was being written we experienced the birth of at least three kids. We hope that the personal relationships forged during this project will continue and that there will be the potential for future collaboration.

We wish to thank those who reviewed the various chapters in this book. Most co-authors participated in that process. In particular, we are indebted to Mr. Petri Komulainen for his scrutiny and review of Chapter 6. We are thankful to Mr. Peter J. Larsson, as an external reviewer, for his review of Chapter 8.

We express our gratitude to Dr. Andrew Logothetis. His encouragement at the outset was significant in prompting us to start the work and to submit the book proposal.

Dr. Osseiran would like, in particular, to acknowledge Ericsson's generosity, through the persons of Dr. Magnus Frodigh, Dr. Claes Tidestav and Dr. Gunnar Bark, for giving ample resources to write the book. In addition, Dr. Göran Klang and Mr. Johan Lundsjö believed in the project and encouraged it from its inception.

We would like to thank Mr. Mark Hammond, Mrs. Sophia Travis and Mrs. Susan Barclay from JohnWiley & Sons for their help to finalize this book. Mr. Hammond encouraged endlessly to initiate the proposal. Mrs. Travis has been always available, efficiently reacting to queries, and with a great sense of humor. We show our appreciations to the antonymous type editors, type setters, designers and proof readers. Finally, Mrs. Shirine Osseiran is greatly thanked for carefully designing the book front cover.

Afif Osseiran

Jose F. Monserrat

Werner Mohr

List of Abbreviations

1G First Generation

2G Second Generation

3G Third Generation

3GPP Third Generation Partnership Project

3GPP2 Third Generation Partnership Project 2

4G Fourth Generation

ABS Advanced Base Station

ACK Acknowledge

AF Amplify-and-Forward

AMBR Aggregated Maximum Bit Rate

AMC Adaptive Modulation and Coding

AMPS Advanced Mobile Phone System

AMS Advanced Mobile Station

AoA Angle of Arrival

AoD Angle of Departure

AP Access Point

APA Adaptive Power Allocation

APP Application

ARP Allocation and Retention Priority

ARQ Automatic Repeat-reQuest

AS Application Server

ASA Angle Spread Arrival

ASD Angle Spread Departure

AVC Advanced Video Coding

AWGN Additive White Gaussian Noise

BuB Busy Burst

BB Base Band

BC Broadcast Channel

BD Block Diagonalization

BE Best Effort

BER Bit Error Rate

BLAST Bell Labs Space-Time architecture

BLER BLock Error Rate

BPSK Binary Phase Shift Keying

BS Base Station

BSR Buffer Status Report

BWA Broadband Wireless Access

CA Carrier Aggregation

CAC Call Admission Control

CC Component Carrier

CCC Cognitive Component Carrier

CCI Co-Channel Interference

CDD Cyclic Delay Diversity

CDF Cumulative Density Function

CDM Code Division Multiplexing

CDMA Code Division Multiple Access

CEPT European Conference of Postal and Telecommunications Administrations

CESAR CEllular Slot Allocation and Reservation

CF Compress-and-Forward

CFI Control Format Indicator

CIR Carrier-to-Interference power Ratio

CJP Centralized Joint Processing

CLA Clustered Linear Array

CLO Cross-Layer Optimization

CoMP Coordinated MultiPoint transmission or reception

CP Cyclic Prefix

CPG Conference Preparatory Group

CPM Conference Preparatory Meeting

CPRI Common Public Radio Interface

CQI Channel Quality Indicator

CR Cognitive Radio

CRC Cyclic Redundancy Check

CRNTI Cell Radio Network Temporary Identifier

CRS Cognitive Radio System

CSG Closed Subscriber Group

CSI Channel State Information

CSIR CSI at the Receiver

CSI-RS Channel State Information Reference Signal

CSIT Channel State Information at the Transmitter

CSMA/CA Carrier Sense Multiple Access With Collision Avoidance

CU Central Unit

D2D Device-to-Device

dB decibel

DB Digital Broadcasting

DCI Downlink Control Indicator

DF Decode-and-Forward

DFT Discrete Fourier Transform

DJP Decentralized Joint Processing

DL Downlink

DLS Direct Link Setup

DM Demodulation

DmF Demodulate-and-Forward

DMO Direct Mode Operation

DM-RS DeModulation Reference Signal

DMT Diversity-Multiplexing-Tradeoff

DNC Diversity Network Codes

DOFDM Discontiguous OFDM

DPC Dirty Paper Coding

DRx Discontinuous Reception

DS Delay Spread

DSA Dynamic Sub-carrier Assignment

D.S.A Dynamic Spectrum Allocation

DSP Digital Signal Processor

DwPTS Downlink Pilot TimeSlot

DySA Dynamic Spectrum Access

EBF Eigen Beam Forming

ECC Electronic Communications Committee

EDCA Enhanced Distributed Channel Access

EDF Exponential Delay Fairness

EDGE Enhanced Data rates for GSM Evolution

EIRP Equivalent Isotropically Radiated Power

EM ElectroMagnetic

E-MBS Enhance Multicast Broadcast Service

eNB eNodeB

EPC Evolved Packet Core

EPS Evolved Packet System

ERO European Radio Communication Office

ETSI European Telecommunications Standards Institute

EU European Union

E-UTRA Evolved Universal Terrestrial Radio Access

E-UTRAN Evolved Universal Terrestrial Radio Access Network

FCC Federal Communications Commission

FDD Frequency Division Duplex

FDM Frequency Division Multiplexing

FDMA Frequency Division Multiple Access

FER Frame Error Rate

FFR Fractional Frequency Reuse

FFT Fast Fourier Transform

FIFO First Input First Output

FM Frequency Management

FSA Fixed Spectrum Assignment

FSS Frequency Selective Scheduling

FUE Femto-UE

GBR Guaranteed Bit Rate

GEK Global Encoding Kernel

GP Guard Period

GPRS General Packet Radio Service

GPS Global Positioning System

GSM Global System for Mobile Communications

GT Game Theory

GTP GPRS Tunneling Protocol

GW Gateway

HARQ Hybrid Automatic Repeat reQuest

H-BS Home Base Station

HeNB Home eNB

HetNet Heterogeneous Network

HHI Heinrich Hertz Institute

HII High Interference Indicator

HK Han-Kobayashi

HNB Home NB

HOL Head-of-line

HSA Hierarchical Spectrum Access

HSDPA High-Speed Downlink Packet Access

HSPA High-Speed Packet Access

HSUPA High Speed Uplink Packet Access

HUE Home User Equipment

HYGIENE HurrY-Guided-Irrelevant-Eminent-NEeds

ICI Inter-Cell Interference

ICIC Inter-Cell Interference Coordination

ICT Information and Communication Technologies

ID Identity

IEEE Institute of Electrical and Electronics Engineers

IEG Independent Evaluation Group

IF Intermediate Frequency

IFFT Inverse Fast Fourier Transform

IMS IP Multimedia Subsystem

IMT International Mobile Telecommunications

IMT-2000 International Mobile Telecommunications 2000

IMT-Advanced International Mobile Telecommunications Advanced

IP Internet Protocol

IRC Interference Rejection Combining

ISI Inter-Symbol Interference

ITU International Telecommunication Union

ITU-R International Telecommunication Union – Radiocommunication Sector

JD Joint Detection

JP Joint Processing

JQS Joint Queue Scheduler

JUS Joint User Scheduling

LA Link Adaptation

LAN Local Area Network

LDPC Low-Density Parity-Check

LMMSE Linear Minimum Mean Square Error

LoS Line of Sight

LRU Logical Resource Unit

LTE Long Term Evolution

LTE-A LTE-Advanced

LTE-Rel-8 LTE Release 8

LTE-Rel-10 LTE Release 10

M2M Machine-to-Machine

MAC Medium Access Control

M.A.C Multiple Access Channel

MARC Multiple Access Relay Channel

MBMS Multimedia Broadcast Multicast Service

MBR Maximum Bit Rate

MBSFN MBMS over Single Frequency Networks

MCI Maximum Carrier to Interference

MCS Modulation and Coding Scheme

MDNC Maximum Diversity Network Codes

MDS Maximum-Distance Separable

MET Multi-user Eigenmode Transmission

MI Mutual Information

MIMO Multiple-Input Multiple-Output

MISO Multiple-Input Single-Output

ML Maximum Likelihood

M-LWDF Modified-Largest Weighted Delay First

MME Mobile Management Entity

MMSE Minimum Mean Square Error

MOS Mean Opinion Score

MRC Maximum Ratio Combining

MSE Mean Square Error

MU Multi-User

MUE Macro UE

MVD Majority Vote Detection

NACK Negative Acknowledge

NAS Non-Access Stratum

NC Network Coding

NC-OFDMA Non-Contiguous OFDMA

N.E Nash Equilibrium

NGMN Next Generation Mobile Network

NLoS Non Line of Sight

NMT Nordic Mobile Telephone

NRT Non-Real-Time

OC Optimum Combining

OCA Opportunistic Carrier Aggregation

OFDM Orthogonal Frequency Division Multiplexing

OFDMA Orthogonal Frequency Division Multiple Access

OI Overload Indicator

OPEX OPerational EXpenditures

OSA Open Spectrum Access

OSI Open Systems Interconnection

OtoI Outdoor to Indoor

PAPC Per-Antenna Power Constraint

PAPR Peak-to-Average Power Ratio

PBCH Physical Broadcast CHannel

PC Power Control

PCFICH Physical Control Format Indicator CHannel

PDC Personal Digital Cellular

PDCCH Physical Downlink Control CHannel

PDN Packet Data Network

PDSCH Physical Downlink Shared CHannel

PF Proportional Fair

PHICH Physical Hybrid Automatic Repeat Request Indicator CHannel

PHR Power Headroom Report

PHY Physical

PJP Partial Joint Processing

PL Path Loss

PMI Precoding Matrix Indicator

P.M.I Preferred Matrix Index

PNC Physical Network Coding

PPF Predictive Proportional Fair

PRACH Physical Random Access CHannel

PRB Physical Resource Block

PRMA Packet Reservation Multiple Access

PRU Physical Resource Unit

PSE Peak Spectral Efficiency

PSK Phase-Shift Keying

PT A Project Team A

p-t-m point-to-multi-point

p-t-p point-to-point

PUCCH Physical Uplink Control CHannel

PUSCH Physical Uplink Shared CHannel

QAM Quadrature Amplitude Modulation

QCI QoS Class Identifier

QoE Quality of Experience

QoS Quality of Service

QPSK Quadrature Phase Shift Keying

RA Radiocommunication Assembly

RAN Radio Access Network

RB Resource Block

RCC Relay Coherent Combining

RCDD Relay Cyclic Delay Diversity

RCPC Rate Compatible Convolutional Codes

Rel-5 Release 5

Rel-6 Release 6

Rel-7 Release 7

Rel-8 Release 8

Rel-9 Release 9

Rel-10 Release 10

ReS Relay Selection

RF Radio Frequency

RI Rank Indicator

RIT Radio Interface Technology

RLC Radio Link Control

RMa Rural Macrocell

RMS Root-Mean-Square

RN Relay Node

RNTP Relative Narrowband Transmit Power

RoF Radio over Fiber

RoR Round Robin

RR Radio Regulations

RRC Radio Resource Control

RRH Remote Radio Heads

RRM Radio Resource Management

RRU Radio Remote Unit

RS Reference Signal

RSD Relay Selection Diversity

RT Real-Time

SAE System Architecture Evolution

SAO Spectrum Access Opportunities

SB Score Based

SC-FDMA Single Carrier – Frequency Division Multiple Access

SCH Synchronization CHannel

SCM Spatial Channel Model

SCME Spatial Channel Model Extended

SCTP Stream Control Transmission Protocol

SDMA Space Division Multiple Access

SDP SemiDefinite Programming

SDR Software Defined Radio

SE Spectrum Engineering

S.E Stackelberg Equilibrium

SpE Split-and-Extend

SF Shadow Fading

SFN Single Frequency Network

SFR Soft Frequency Reuse

S-GW Serving Gateway

SIC Successive Interference Cancellation

SIMO Single Input Multiple Output

SINR Signal to Interference plus Noise Ratio

SIP Session Initiation Protocol

SISO Single Input Single Output

SLNR Signal to Leakage and Noise Ratio

SMS Short Message Service

SNIR Signal-to-Noise-plus-Interference Ratio

SNR Signal to Noise Ratio

SOCP Second Order Cone Programming

SON Self-Organized Network

SR Source Relay

SRIT Set of Radio Interface Technologies

SRS Sounding Reference Signal

SRUS Separated Random User Scheduling

SSC Selection and Soft Combining

STBC Space Time Block Code

STTC Space-Time Trellis Codes

STTD Space Time Transmit Diversity

SU Single-User

SVC Scalable Video Coding

SVD Singular Value Decomposition

TACS Total Access Communications System

TASB Traffic-Aware Score Based

TC Turbo Code

TD-CDMA Time Division CDMA

TDD Time Division Duplex

TDLS Tunneled Direct Link Setup

TDM Time Division Multiplexing

TDMA Time Division Multiple Access

TETRA Terrestrial Trunked Radio

TLabs Deutsche Telekom Laboratories

TMO Trunked Mode Operation

TMSI Temporary Mobile Subscriber Identity

TP Throughput

TTI Transmission Time Interval

TUB Technical University of Berlin

TV Television

UCI Uplink Control Information

UE User Equipment

UEPS Urgency and Efficiency based Packet Scheduler

UG User Grouping

UL Uplink

ULA Uniform Linear Array

UMa Urban Macrocell

UMi Urban Microcell

UMTS Universal Mobile Telecommunication System

UpPTS Uplink Pilot Timeslot

UPS Utility Predictive Scheduler

URI Uniform Resource Indicator

URL Uniform Resource Locator

USB Universal Serial Bus

VAA Virtual Antenna Array

VLAN Virtual Local Area Network

VoIP Voice over IP

WARC World Administrative Radio Conference

WCDMA Wideband Code Division Multiple Access

WiMAX Worldwide Interoperability for Microwave Access

WINNER Wireless World Initiative New Radio

WINNER+ Wireless World Initiative New Radio +

WLAN Wireless Local Area Network

WP Working Party

WPAN Wireless Personal Area Networks

WRC World Radiocommunication Conference

ZF Zero Forcing

List of Contributors

Dr. Günther Auer DOCOMO, Munich, Germany

Prof.Mats Bengtsson Royal Institute of Technology (KTH), Stockholm, Sweden

Dr. Mehdi Bennis Centre for Wireless Communications, University of Oulu, Finland

Prof. Slimane Ben Slimane Royal Institute of Technology (KTH), Stockholm, Sweden

Dr. Federico Boccardi Bell Laboratories, Alcatel Lucent, Vimercate, Italy

Mr. Mauro Boldi Telecom Italia, Torino, Italy

Mr. Jorge Cabrejas Universitat Politecnica de Valencia - iTEAM, Valencia, Spain

Mrs. Valeria D'Amico Telecom Italia, Torino, Italy

Dr. Klaus Doppler Nokia Research Center, Helsinki, Finland

Dr. Xavier Gelabert Universitat Politecnica de Valencia - iTEAM, Valencia, Spain

Mr. Alexandre Gouraud Orange Labs, Paris, France

Dr. Eric Hardouin Orange Labs, Paris, France

Mr. Pekka Jänis Nokia Research Center, Helsinki, Finland

Dr. Volker Jungnickel Fraunhofer Heinrich-Hertz-Institut, Berlin, Germany

Mr. Petri Komulainen Centre for Wireless Communications, University of Oulu, Finland

Mr. David Martin-Sacristán Universitat Politecnica de Valencia - iTEAM, Valencia, Spain

Dr.Werner Mohr Nokia Siemens Networks GmbH & Co. KG, Munich, Germany

Dr. Jose F. Monserrat Universitat Politecnica de Valencia - iTEAM, Valencia, Spain

Mrs. Miia Mustonen VTT Technical Research Centre, Oulu, Finland

Mr. Magnus Olsson Ericsson AB, Stockholm, Sweden

Dr. Afif Osseiran Ericsson AB, Stockholm, Sweden

Dr. Cassio Ribeiro Nokia Research Center, Helsinki, Finland

Dr. Peter Rost NEC Laboratories Europe, Heidelberg, Germany

Dr. Ahmed Saadani Orange Labs, Paris, France

Mr. Krystian Safjan Nokia Siemens Networks Sp. z.o.o, Wroclaw, Poland

Dr. Hendrik Schöneich Qualcomm, Nürnberg, Germany

Mr. Per Skillermark Ericsson AB, Stockholm, Sweden

Mr. Pawel Sroka Poznan University of Technology, Poznan, Poland

Dr. Tommy Svensson Chalmers University of Technology (CTH), Gothenburg, Sweden

Mr. Lars Thiele Fraunhofer Heinrich-Hertz-Institut, Berlin, Germany

Dr. Antti Tölli Centre for Wireless Communications, University of Oulu, Finland

Mr. Jaakko Vihriälä Nokia Siemens Networks Oy, Oulu, Finland

Dr. Marc Werner Qualcomm, Nürnberg, Germany

Dr. Ming Xiao Royal Institute of Technology (KTH), Stockholm, Sweden

Chapter 1

Introduction

Afif Osseiran, Jose F. Monserrat and Werner Mohr

1.1 Market and Technology Trends

Social, economic and political factors determine the development of the mobile communications business. Consumer demand, the economic performance of operators and government policies are some of the aspects that affect technological advances, operators' capital investments and the regulatory environment. The mobile communications sector has been characterized by a worldwide rapid increase in the number of users. During the 1980s only a handful of people had a mobile phone. At the end of the 1980s, the number of cellular subscribers was merely around 5 million. With the introduction of the Second Generation (2G) cellular systems in 1991, the ambition was to popularize progressively the usage of mobile phones by making them affordable to a large part of the population. Progress in micro electronics then made it possible to produce cheaper mobile phones. The technology advanced and gradually increasing competition between mobile vendors made it necessary to reduce the cost of cellular infrastructures. The second part of the 1990s, witnessed an extraordinary surge in the number of mobile subscribers in the developed countries. In total, the number was close to half a billion. Progress continued worldwide at a frenetic pace. According to the International Telecommunication Union (ITU), in the last seven years the number of worldwide subscribers has grown from 1.7 billion to more than 5.3 billion (75.42% of the world population), which implies growing at a compound annual growth rate of 21%. Astonishingly, in 2002 and within only two decades, mobile subscribers surpassed fixed-telephone line subscribers (ITU n.d). The evolution of the number of mobile and fixed line subscribers from the year 1996 to 2010 is shown in Figure 1.1.

Figure 1.1 Evolution of mobile and fixed phone subscriptions from 1996 to 2010

Even though these numbers are quite significant, it is worth noting that the mobile communications sector has reached a saturation point in terms of the number of subscribers in a large number of markets, but new systems result in technology upgrades of networks and devices, which offer a significantly improved user experience and capabilities and provide new business opportunities. In the European Union, mobile penetration rate is over 110% of the total population, whereas in developed Asian countries has reached 80%, as in the United States and Eastern Europe where the growth of mobile services has been quite important in recent years. There is still room for mid-term growth of less-developed markets. Operators in saturated markets need to foster demand for new services to guarantee their revenues.

That is why the mobile communications sector, today more than ever, seeks to put new telecommunication services on the market through mobile devices. Among these services social networks, location-based services, augmented reality, mobile TV, video on demand, interactive games and high quality music were applications added to mobile devices to ensure an upturn in usage of mobile services and, consequently, revenues. From 2007 there has been a quite significant increase in traffic demand. Apart from new services, several factors are fostering the mobile communications sector: the increase of Third Generation (3G) penetration as users rapidly migrate from 2G to 3G services; the increasing penetration of Universal Serial Bus (USB) modems and data cards, as well as smart phones and tablets, together with the increasing availability of easy-to-use data applications; the proliferation of flat-rate service bundles, which is also changing service mixes towards more usage-intensive services; and the increasing usage of 3G devices indoors, among other things. All these factors are making mobile data demand overload the capacity of 3G networks and will force next generation mobile systems to be designed according to take this trend into account. Rather than just requiring an increase in throughput, these developments will require improving the ubiquity of the Quality of Experience (QoE) Indicators, that is, allowing the mobile users to experience high QoE values in any geographical position, not only close to the Base Station (BS), while minimizing the radio resource and energy consumption.

In fact, current market forecasts predict mobile Internet penetration to double by 2015, which represents a real threat of congestion for current cellular networks. Indeed, recent analysis of the evolution of mobile broadband subscribers show that, starting in 2007, there has been a significant increase in their number and their traffic demands. In many countries where there are developed markets, mobile data consumption has increased from 2008 and 2010 and is growing exponentially as can be seen in Figure 1.2. Traditional asymmetric traffic – with more data in Downlink (DL) than in Uplink (UL) – is daily becoming more symmetrical. The increase in the usage of wireless systems is driving the industry to seek new methods to boost the capacity of cellular networks, that is, the number of users served or transmitted bits over the air interface.

Figure 1.2 Exponential increase of mobile data traffic. UMTS Forum (UMTS-Forum 2010)

The decision to adopt such methods, which may involve either improving a specific cellular standard or adopting a completely new technology through a standard change, has been seen as strategic and the decision is not based purely on technical or economic grounds. The influence of economic/political factors – through influential governmental and industrial players – is undeniable.

1.2 Technology Evolution

The first commercial analog mobile communication systems were deployed in the 1950s and 1960s, although with low penetration. The year 1981 witnessed the birth of the first commercial deployments of the First Generation (1G) mobile cellular standards such as Nordic Mobile Telephone (NMT), in Saudi Arabia and the Nordic countries, C-Netz in Germany, Portugal and South Africa, Total Access Communications System (TACS) in the United Kingdom and Analog Advanced Mobile Phone System (AMPS) in the Americas. The 1G standards are called the analog standards since they utilize analog technology. The beginning of the 1990s witnessed the introduction of 2G, characterized by the adoption of digital technology. This technology allowed considerable improvements in voice quality, capacity and growth potential towards advanced applications as well as the development of Short Message Service (SMS) messaging, a form of data transmission. The European Conference of Postal and Telecommunications Administrations (CEPT) decided in 1982 to develop a pan-European 2G mobile communication system. This was the starting point of the Global System for Mobile Communications (GSM), the dominant 2G standard, which was deployed internationally from 1991. In the beginning, the main objective of GSM was the support of voice telephony and international roaming with a single-system across Europe. GSM is based on a hybrid Time Division Multiple Access (TDMA) Frequency Division Multiple Access (FDMA) method, in contrast with 1G systems based only on FDMA (Hillebrand 2002). In parallel with GSM, other digital 2G systems were developed globally and competed with each other. These other main 2G standards include IS-136, also known as D-AMPS, IS-95A also known as CDMAOne – used mainly in the Americas – and finally Personal Digital Cellular (PDC) – used exclusively in Japan. In contrast to GSM, the IS-95 technologies are based on Code Division Multiple Access (CDMA)(Viterbi 1995).

The evolution of the 2G, called 2.5G, allowed the introduction of packet-switched services in addition to voice, the most significant circuit switched service. The main 2.5G standards, General Packet Radio Service (GPRS) and IS-95B, are basically an extension of GSM and IS-95A, respectively.

Shortly after the 2G became operational, industrial players were already preparing and discussing the next wireless generation standards. In January 1998, CDMA under two variants – Wideband Code Division Multiple Access (WCDMA) and Time Division CDMA (TD-CDMA) – was adopted by the European Telecommunications Standards Institute (ETSI) as a Universal Mobile Telecommunication System (UMTS) as the 3G mobile communication system, also called International Mobile Telecommunications 2000 (IMT-2000). As a member of the IMT-2000 family of standards, the Third Generation Partnership Project (3GPP) developed UMTS technology using both WCDMA and TD-CDMA modulation schemes (Holma and Toskala 2000) and is generally favored in Japan and countries using GSM. On the other hand CDMA2000, initially an outgrowth of the 2G CDMA standard IS-95, is mainly dominant in the Americas and Korea.

New specifications have been developed within the framework of 3GPP together known as 3G Evolution. For this evolution, two Radio Access Network (RAN) approaches and an evolution of the core network have been suggested. The first RAN approach is High-Speed Packet Access (HSPA) – referred to as a 3.5G technology. HSPA comprises High-Speed Downlink Packet Access (HSDPA), added in Release 5 (Rel-5), and High Speed Uplink Packet Access (HSUPA), added in Release 6 (Rel-6) of UMTS. Both enhance the packet data rate, respectively to 14.6 Mbps in DL and to 5.76 Mbps in UL. Again, HSPA is based on WCDMA and is completely backward compatible with UMTS. The philosophy behind this radio network approach is to add new features while still serving the old mobiles, and is further applied in HSPA Evolution, also known as HSPA+. This is a good solution for the mid-term future. The equivalent evolution in CDMA2000 are 1xEV-DO and 1xEV-DV. While CDMA 1xEV-DO started deployment in 2003, HSPA and CDMA 1xEV-DV entered into service in 2006.

The second UMTS evolution is called Long Term Evolution (LTE) (Dahlman et al. 2008; Sesia et al. 2011) and the evolved core network is known as Evolved Packet Core (EPC). The target of LTE is high performance and reduced cost for the radio access. LTE is a radio interface designed from scratch. Hence, in contrast to HSPA, LTE is not backward compatible with UMTS. However, the design is clearly influenced by earlier specification work done by 3GPP. At the end of 2007 first LTE specifications were approved. The LTE system has peak data rates of around 326 Mbps, increased spectral efficiency and significantly shorter latency than previous systems. LTE is based on Orthogonal Frequency Division Multiple Access (OFDMA) and advanced spatial processing Multiple-Input Multiple-Output (MIMO). The Next Generation Mobile Network (NGMN) initiative formulated requirements on further developments of mobile communications NGMN. Such requirements are mainly related to a flat network architecture based on the Internet Protocol (IP) for cost reduction, higher spectral efficiency for better use of the available frequency spectrum, lower latency and higher peak data rates with flexible allocation of data rates to users. Additional requirements are a high cell average throughput and sufficiently high cell edge capacity in order to cover the expected increasing data traffic with growing user density. LTE was developed to meet these requirements, and this was an important step towards the next International Mobile Telecommunications Advanced (IMT-Advanced) standard (see section 1.3).

With regard to the cellular systems market, today, the GSM family (GSM, GPRS and Enhanced Data rates for GSM Evolution (EDGE)) is the dominant second-generation mobile communication standard with a global market share – at the end of 2010 – of more than 79% and 4.18 billion subscribers in more than 200 countries (GSA n.d.). On the other hand, the number of 3G subscribers including HSPA has risen to 619 million subscribers, which represents 11.7% of the market (GSA n.d.). The main competitor to GSM is IS-95 CDMA that serves the rest of the market. Currently, the main subscriber growth markets for the GSM system are emerging markets, such as China with about seven million new subscribers per month and India with about 16 million new subscribers per month. With respect to LTE, at the end of 2010 seven LTE networks were commercially launched, being still an incipient technology. The evolution of cellular mobile systems is shown in Figure 1.3.

Figure 1.3 Evolution of wireless communication systems

With regard to the peak data rates of cellular systems, from the onset of the introduction of cellular systems and until the mid-1990s the data peaked at approximately around 10 kbps. The peak data rate was lifted to 160 kbps with the introduction of GPRS. Only few years later, the first UMTS systems supported peak data rates of 384 kbps. Nowadays, HSDPA supports peak data rates from 7.2 Mbps to about 14.6 Mbps (by using adaptive modulation and coding with higher-order modulation and multicode transmission (Holma and Toskala 2007). HSPA-Evolved specified by 3GPP Release 7 (Rel-7), the second phase of HSDPA, can achieve data rates of up to 42 Mbps (assuming 64-Quadrature Amplitude Modulation (QAM)). The coming technology, LTE, will see the peak data rate reaching 326 Mbps. Finally, in a few years, IMT-Advanced will theoretically push the peak rate to attain the huge throughput rate of 1.6 Gbps. The evolution of the peak data rate from years 1990 to 2015 is shown in Figure 1.4.

Figure 1.4 Evolution of downlink peak rate from years 1990 to 2015

In parallel with these developments in the telecommunications industry, the wireless information and telecommunications sector provides different IP-based access systems for different application areas. Wireless Local Area Network (WLAN) systems, Institute of Electrical and Electronics Engineers (IEEE) standard 802.11, are used for local and short-range applications without mobility. WLAN systems are widely available globally. Wireless Personal Area Networks (WPAN) are standardized by IEEE 802.15 for very short ranges and high throughput. Broadband Wireless Access (BWA) systems, according to IEEE 802.16, target higher ranges including the support of user mobility (IEEE-ISTO n.d.; IEEE-SG n.d.). The BWA Worldwide Interoperability for Microwave Access (WiMAX) system is a member of the IMT-2000 family (WiMAX n.d.). As with UMTS and LTE, an evolution process has taken place within IEEE. In fact, the IEEE wireless system will evolve from the current WiMAX toward the new IEEE 802.16m standard, which is an IMT-Advanced technology.

1.3 Development of IMT-Advanced and Beyond

The radio spectrum is a scarce resource that has considerable economic and social importance. In general, governments of every country decide on the spectrum allocation. On the other hand, global coordination of spectrum usage is in the responsibility of ITU, which, through spectrum regulation, aims to facilitate spectrum harmonization for global roaming to reduce equipment cost by means of global economies of scale. Since 1992, and in the framework of the International Telecommunication Union – Radiocommunication Sector (ITU-R), the World Administrative Radiocommunications Conference (WARC 1992) has reached quite significant agreements at a global level to designate specific frequency bands to International Mobile Telecommunications (IMT) standards. The objective of this initiative is to specify a set of requirements in terms of transmission capacity and Quality of Service (QoS), in such a way that if a certain technology fulfills all these requirements then the technology is included by ITU in the IMT-2000 standards. This inclusion is an official endorsement of the technologies that might motivate the concerned players (e.g. operators, telecommunications providers, etc.) to take the technologies into account and to consider investing in them. Furthermore it allows these standards to make use of the frequency bands designated for IMT. With the aim of coordinating the global use of spectrum, every three to four years ITU-R holds the World Radiocommunication Conference (WRC), where ITU radio regulations that govern spectrum distribution are adopted.

World Radiocommunication Conference (WRC)-07 identified additional frequency spectrum for mobile and wireless communications. The first step towards this new spectrum allocation was performing an in-depth study of the mobile market forecast and the development of spectrum requirements for the increasing service demand. Reports predicted the total spectrum bandwidth requirements for mobile communication systems in the year 2020 to be 1280 MHz and 1720 MHz for low and high user-demand scenarios, respectively. Bearing in mind that the spectrum bandwidth designed by ITU as IMT was much lower than this forecast (693 MHz in Region 1 (Europe, Middle East and Africa, and Russia), 723 MHz in Region 2 (Americas) and 749 MHz in Region 3 (Asia and Oceania)), and given that the time elapsed between the adoption of the radio regulations and the definitive allocation of a frequency band to operators takes from 5 to 10 years, the WRC-07 that took place in Geneva ended with the identification of new frequency bands for IMT technologies.

Figure 1.5 depicts the current state of the frequency bands reserved for IMT. Despite not fully corresponding to what was targeted, the new spectrum allocated for mobile communications will allow operators to satisfy the initial needs with the deployment of technologies towards IMT-Advanced. Furthermore, the increasing demand for mobile services has been progressively recognized with additional spectrum, a trend that is expected to be maintained in future WRCs.

Figure 1.5 Mobile frequency bands allocated for IMT technologies

With this strong endorsement, the race towards IMT-Advanced successfully reached its end in the autumn of 2010. Anticipating the invitation from ITU, in March 2008 3GPP initiated a study item on LTE-Advanced (LTE-A) (also called LTE-Release 10 (Rel-10)). At IEEE, the IMT-Advanced (candidate) – IEEE 802.16m – was finalized in September 2009. These two technologies, LTE-A (3GPP 2010) and IEEE 802.16m (IEEE 2010) were submitted to ITU as IMT-Advanced technology candidates. Based on the evaluation results submitted to ITU-R in June 2010, ITU-R announced in October 2010 that both LTE-A and IEEE 802.16m proposals successfully met all of the criteria for the first release of IMT-A.

Compared to its predecessor, the IMT-Advanced technologies rely on several new features such as Carrier Aggregation (CA), improved MIMO support, relaying and improved support for heterogeneous deployments. These features are described and analyzed in this book. The most promising ideas within those features for IMT-Advanced and beyond are explained and illustrated.

Advanced Radio Resource Management (RRM) While, from technological point of view, physical layer improvements are already close to their upper limit and only advanced antenna systems seem to be able to improve system performance, there is still a high potential to maximize efficiency in radio resource and interference management. Medium Access Control (MAC) aspects are attracting huge attention. Chapter 2 presents some innovative concepts for advanced RRM that have been identified by the research community for potential inclusion in IMT-Advanced and beyond.

Spectrum and Carrier Aggregation (CA) IMT-Advanced requirements establish a minimum support of 1 Gbps and 100 Mbps peak rates for low-mobility and high-mobility users, respectively. In order to fulfill these challenging requirements, wider channel bandwidth than legacy 3G systems have to be supported. However, as shown in Figure 1.5, the available spectrum resources are spread out over different frequency bands and with different bandwidths. Hence, CA, the concept of aggregation of continuous or discontinuous spectrum will be necessary in order to achieve wider effective carrier bandwidth. In addition, spectrum sharing, due to the scarcity of wide contiguous frequency bands, is crucial in order to optimize spectrum usage. These two concepts, CA and spectrum sharing, will be treated in Chapters 3 and 4, respectively.

MIMO In MIMO communications, multiple antenna elements are employed both in the transmitter and the receiver, in order to obtain increased data rates or improved reliability compared to single-antenna transmission. In order to address the challenge to offer very high data peak rates, IMT-Advanced has moved the emphasis from simple transmit diversity modes to spatial multiplexing and beamforming. In fact, LTE-A and IEEE 802.16m have evolved in the same direction: up to eight transmit antennas at the BS and up to four transmit antennas at the User Equipment (UE) are supported. Further, the standards are progressing toward the full adoption of Multi-User (MU)-MIMO transmissions, that is, the BS can spatially multiplex data streams intended for different UEs. Chapter 5 describes the latest advances in MIMO techniques.

Relaying With the growth of data traffic and the emergence of new services, there is a need to enhance coverage and/or capacity in specific locations. In addition, fast roll-outs are sometimes required to extend a network, implying a very dynamic and fast change of operator's infrastructure. Relaying techniques are emerging as an attractive solution to fill these needs. In fact, they are by construction characterized by ease of deployment (due to in-band backhauling) and reduced deployment cost compared to a regular BS. Chapter 7 overviews relaying techniques in general and describes