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`UNDERSTANDING LTE
`WITH MATLAB®
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`UNDERSTANDING LTE
`WITH MATLAB®
`FROM MATHEMATICAL MODELING
`TO SIMULATION AND PROTOTYPING
`
`Dr Houman Zarrinkoub
`MathWorks, Massachusetts, USA
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`© 2014, John Wiley & Sons, Ltd
`
`Registered office
`John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, United Kingdom
`
`For details of our global editorial offices, for customer services and for information about how to apply for
`permission to reuse the copyright material in this book please see our website at www.wiley.com.
`
`The right of the author to be identified as the author of this work has been asserted in accordance with the Copyright,
`Designs and Patents Act 1988.
`
`All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any
`form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by the UK
`Copyright, Designs and Patents Act 1988, without the prior permission of the publisher.
`
`Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be
`available in electronic books.
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`Designations used by companies to distinguish their products are often claimed as trademarks. All brand names and
`product names used in this book are trade names, service marks, trademarks or registered trademarks of their
`respective owners. The publisher is not associated with any product or vendor mentioned in this book.
`
`Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts in preparing
`this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of
`this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. It is
`sold on the understanding that the publisher is not engaged in rendering professional services and neither the
`publisher nor the author shall be liable for damages arising herefrom. If professional advice or other expert
`assistance is required, the services of a competent professional should be sought.
`MATLAB® is a trademark of The MathWorks, Inc. and is used with permission. The MathWorks does not warrant
`the accuracy of the text or exercises in this book. This book’s use or discussion of MATLAB® software or related
`products does not constitute endorsement or sponsorship by The MathWorks of a particular pedagogical approach or
`particular use of the MATLAB® software.
`
`Library of Congress Cataloging-in-Publication Data
`
`Zarrinkoub, Houman.
`Understanding LTE with MATLAB : from mathematical foundation to simulation, performance evaluation and
`implementation / Houman Zarrinkoub.
`pages cm
`Includes bibliographical references and index.
`ISBN 978-1-118-44341-5 (hardback)
`1. Long-Term Evolution (Telecommunications)–Computer simulation. 2. MATLAB. I. Title.
`TK5103.48325.Z37 2014
`621.3845′6–dc23
`
`2013034138
`
`A catalogue record for this book is available from the British Library.
`
`ISBN: 9781118443415
`
`Typeset in 10/12pt TimesLTStd by Laserwords Private Limited, Chennai, India
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`1
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`Contents
`
`Preface
`
`List of Abbreviations
`
`1
`1.1
`1.2
`1.3
`1.4
`1.5
`1.6
`1.7
`
`Introduction
`Quick Overview of Wireless Standards
`Historical Profile of Data Rates
`IMT-Advanced Requirements
`3GPP and LTE Standardization
`LTE Requirements
`Theoretical Strategies
`LTE-Enabling Technologies
`1.7.1
`OFDM
`1.7.2
`SC-FDM
`1.7.3
`MIMO
`1.7.4
`Turbo Channel Coding
`1.7.5
`Link Adaptation
`LTE Physical Layer (PHY) Modeling
`1.8
`LTE (Releases 8 and 9)
`1.9
`LTE-Advanced (Release 10)
`1.10
`1.11 MATLAB® and Wireless System Design
`1.12 Organization of This Book
`References
`
`2
`2.1
`2.2
`2.3
`2.4
`2.5
`2.6
`2.7
`
`Overview of the LTE Physical Layer
`Air Interface
`Frequency Bands
`Unicast and Multicast Services
`Allocation of Bandwidth
`Time Framing
`Time–Frequency Representation
`OFDM Multicarrier Transmission
`2.7.1
`Cyclic Prefix
`2.7.2
`Subcarrier Spacing
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`17
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`Contents
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`2.11
`
`2.8
`2.9
`2.10
`
`Resource Block Size
`2.7.3
`Frequency-Domain Scheduling
`2.7.4
`Typical Receiver Operations
`2.7.5
`Single-Carrier Frequency Division Multiplexing
`Resource Grid Content
`Physical Channels
`2.10.1
`Downlink Physical Channels
`2.10.2
`Function of Downlink Channels
`2.10.3
`Uplink Physical Channels
`2.10.4
`Function of Uplink Channels
`Physical Signals
`2.11.1
`Reference Signals
`2.11.2
`Synchronization Signals
`2.12 Downlink Frame Structures
`2.13 Uplink Frame Structures
`2.14 MIMO
`Receive Diversity
`2.14.1
`Transmit Diversity
`2.14.2
`Spatial Multiplexing
`2.14.3
`Beam Forming
`2.14.4
`Cyclic Delay Diversity
`2.14.5
`2.15 MIMO Modes
`2.16
`PHY Processing
`2.17 Downlink Processing
`2.18 Uplink Processing
`2.18.1
`SC-FDM
`2.18.2
`MU-MIMO
`2.19 Chapter Summary
`References
`MATLAB® for Communications System Design
`3
`System Development Workflow
`3.1
`Challenges and Capabilities
`3.2
`Focus
`3.3
`Approach
`3.4
`PHY Models in MATLAB
`3.5
`3.6 MATLAB
`3.7 MATLAB Toolboxes
`3.8
`Simulink
`3.9 Modeling and Simulation
`3.9.1
`DSP System Toolbox
`3.9.2
`Communications System Toolbox
`3.9.3
`Parallel Computing Toolbox
`3.9.4
`Fixed-Point Designer
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`Contents
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`3.10
`
`3.11
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`Prototyping and Implementation
`3.10.1
`MATLAB Coder
`3.10.2
`Hardware Implementation
`Introduction to System Objects
`3.11.1
`System Objects of the Communications System Toolbox
`3.11.2
`Test Benches with System Objects
`3.11.3
`Functions with System Objects
`3.11.4
`Bit Error Rate Simulation
`3.12 MATLAB Channel Coding Examples
`3.12.1
`Error Correction and Detection
`3.12.2
`Convolutional Coding
`3.12.3
`Hard-Decision Viterbi Decoding
`3.12.4
`Soft-Decision Viterbi Decoding
`3.12.5
`Turbo Coding
`3.13 Chapter Summary
`References
`
`4.2
`
`4.3
`4.4
`
`4.5
`
`Modulation and Coding
`4
`4.1 Modulation Schemes of LTE
`4.1.1
`MATLAB Examples
`4.1.2
`BER Measurements
`Bit-Level Scrambling
`4.2.1
`MATLAB Examples
`4.2.2
`BER Measurements
`Channel Coding
`Turbo Coding
`4.4.1
`Turbo Encoders
`4.4.2
`Turbo Decoders
`4.4.3
`MATLAB Examples
`4.4.4
`BER Measurements
`Early-Termination Mechanism
`4.5.1
`MATLAB Examples
`4.5.2
`BER Measurements
`4.5.3
`Timing Measurements
`Rate Matching
`4.6.1
`MATLAB Examples
`4.6.2
`BER Measurements
`Codeblock Segmentation
`4.7.1
`MATLAB Examples
`LTE Transport-Channel Processing
`4.8.1
`MATLAB Examples
`4.8.2
`BER Measurements
`Chapter Summary
`References
`
`4.6
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`4.7
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`4.8
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`4.9
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`Contents
`
`5
`5.1
`
`OFDM
`Channel Modeling
`5.1.1
`Large-Scale and Small-Scale Fading
`5.1.2
`Multipath Fading Effects
`5.1.3
`Doppler Effects
`MATLAB® Examples
`5.1.4
`Scope
`5.2
`5.3 Workflow
`5.4
`OFDM and Multipath Fading
`5.5
`OFDM and Channel-Response Estimation
`5.6
`Frequency-Domain Equalization
`5.7
`LTE Resource Grid
`5.8
`Configuring the Resource Grid
`5.8.1
`CSR Symbols
`5.8.2
`DCI Symbols
`5.8.3
`BCH Symbols
`5.8.4
`Synchronization Symbols
`5.8.5
`User-Data Symbols
`Generating Reference Signals
`5.9
`5.10 Resource Element Mapping
`5.11 OFDM Signal Generation
`5.12 Channel Modeling
`5.13 OFDM Receiver
`5.14 Resource Element Demapping
`5.15 Channel Estimation
`5.16
`Equalizer Gain Computation
`5.17 Visualizing the Channel
`5.18 Downlink Transmission Mode 1
`5.18.1
`The SISO Case
`5.18.2
`The SIMO Case
`5.19 Chapter Summary
`References
`
`MIMO
`6
`Definition of MIMO
`6.1
`6.2 Motivation for MIMO
`6.3
`Types of MIMO
`6.3.1
`Receiver-Combining Methods
`6.3.2
`Transmit Diversity
`6.3.3
`Spatial Multiplexing
`Scope of MIMO Coverage
`6.4
`6.5 MIMO Channels
`®
`Implementation
`6.5.1
`MATLAB
`6.5.2
`LTE-Specific Channel Models
`6.5.3
`MATLAB Implementation
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`Contents
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`Initializing MIMO Channels
`6.5.4
`Adding AWGN
`6.5.5
`Common MIMO Features
`6.6.1
`MIMO Resource Grid Structure
`6.6.2
`Resource-Element Mapping
`6.6.3
`Resource-Element Demapping
`6.6.4
`CSR-Based Channel Estimation
`6.6.5
`Channel-Estimation Function
`6.6.6
`Channel-Estimate Expansion
`6.6.7
`Ideal Channel Estimation
`6.6.8
`Channel-Response Extraction
`Specific MIMO Features
`6.7.1
`Transmit Diversity
`6.7.2
`Transceiver Setup Functions
`6.7.3
`Downlink Transmission Mode 2
`6.7.4
`Spatial Multiplexing
`6.7.5
`MIMO Operations in Spatial Multiplexing
`6.7.6
`Downlink Transmission Mode 4
`6.7.7
`Open-Loop Spatial Multiplexing
`6.7.8
`Downlink Transmission Mode 3
`Chapter Summary
`References
`
`6.6
`
`6.7
`
`6.8
`
`7
`7.1
`7.2
`
`Link Adaptation
`System Model
`Link Adaptation in LTE
`7.2.1
`Channel Quality Estimation
`7.2.2
`Precoder Matrix Estimation
`7.2.3
`Rank Estimation
`7.3 MATLAB® Examples
`7.3.1
`CQI Estimation
`7.3.2
`PMI Estimation
`7.3.3
`RI Estimation
`Link Adaptations between Subframes
`7.4.1
`Structure of the Transceiver Model
`7.4.2
`Updating Transceiver Parameter Structures
`Adaptive Modulation
`7.5.1
`No Adaptation
`7.5.2
`Changing the Modulation Scheme at Random
`7.5.3
`CQI-Based Adaptation
`7.5.4
`Verifying Transceiver Performance
`7.5.5
`Adaptation Results
`Adaptive Modulation and Coding Rate
`7.6.1
`No Adaptation
`7.6.2
`Changing Modulation Scheme at Random
`7.6.3
`CQI-Based Adaptation
`
`7.4
`
`7.5
`
`7.6
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`Contents
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`7.7
`
`Verifying Transceiver Performance
`7.6.4
`Adaptation Results
`7.6.5
`Adaptive Precoding
`7.7.1
`PMI-Based Adaptation
`7.7.2
`Verifying Transceiver Performance
`7.7.3
`Adaptation Results
`Adaptive MIMO
`7.8.1
`RI-Based Adaptation
`7.8.2
`Verifying Transceiver Performance
`7.8.3
`Adaptation Results
`Downlink Control Information
`7.9.1
`MCS
`7.9.2
`Rate of Adaptation
`7.9.3
`DCI Processing
`7.10 Chapter Summary
`References
`
`7.8
`
`7.9
`
`8
`8.1
`
`8.2
`8.3
`
`8.4
`8.5
`
`8.6
`
`8.7
`
`System-Level Specification
`System Model
`8.1.1
`Transmitter Model
`8.1.2
`MATLAB Model for a Transmitter Model
`8.1.3
`Channel Model
`8.1.4
`MATLAB Model for a Channel Model
`8.1.5
`Receiver Model
`8.1.6
`MATLAB Model for a Receiver Model
`System Model in MATLAB
`Quantitative Assessments
`8.3.1
`Effects of Transmission Modes
`8.3.2
`BER as a Function of SNR
`8.3.3
`Effects of Channel-Estimation Techniques
`8.3.4
`Effects of Channel Models
`8.3.5
`Effects of Channel Delay Spread and Cyclic Prefix
`8.3.6
`Effects of MIMO Receiver Algorithms
`Throughput Analysis
`System Model in Simulink
`8.5.1
`Building a Simulink Model
`8.5.2
`Integrating MATLAB Algorithms in Simulink
`8.5.3
`Parameter Initialization
`8.5.4
`Running the Simulation
`8.5.5
`Introducing a Parameter Dialog
`Qualitative Assessment
`8.6.1
`Voice-Signal Transmission
`8.6.2
`Subjective Voice-Quality Testing
`Chapter Summary
`References
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`285
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`289
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`293
`294
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`Contents
`
`9.7
`
`9.8
`
`Simulation
`9
`Speeding Up Simulations in MATLAB
`9.1
`9.2 Workflow
`9.3
`Case Study: LTE PDCCH Processing
`9.4
`Baseline Algorithm
`9.5 MATLAB Code Profiling
`9.6 MATLAB Code Optimizations
`9.6.1
`Vectorization
`9.6.2
`Preallocation
`9.6.3
`System Objects
`Using Acceleration Features
`9.7.1
`MATLAB-to-C Code Generation
`9.7.2
`Parallel Computing
`Using a Simulink Model
`9.8.1
`Creating the Simulink Model
`9.8.2
`Verifying Numerical Equivalence
`9.8.3
`Simulink Baseline Model
`9.8.4
`Optimizing the Simulink Model
`GPU Processing
`9.9.1
`Setting up GPU Functionality in MATLAB
`9.9.2
`GPU-Optimized System Objects
`9.9.3
`Using a Single GPU System Object
`9.9.4
`Combining Parallel Processing with GPUs
`9.10 Case Study: Turbo Coders on GPU
`9.10.1
`Baseline Algorithm on a CPU
`9.10.2
`Turbo Decoder on a GPU
`9.10.3
`Multiple System Objects on GPU
`9.10.4
`Multiple Frames and Large Data Sizes
`9.10.5
`Using Single-Precision Data Type
`9.11 Chapter Summary
`
`9.9
`
`Prototyping as C/C++ Code
`10
`10.1 Use Cases
`10.2 Motivations
`10.3 Requirements
`10.4 MATLAB Code Considerations
`10.5 How to Generate Code
`10.5.1
`Case Study: Frequency-Domain Equalization
`10.5.2
`Using a MATLAB Command
`10.5.3
`Using the MATLAB Coder Project
`Structure of the Generated C Code
`Supported MATLAB Subset
`10.7.1
`Readiness for Code Generation
`10.7.2
`Case Study: Interpolation of Pilot Signals
`10.8 Complex Numbers and Native C Types
`
`10.6
`10.7
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`Contents
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`483
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`10.9
`
`Support for System Toolboxes
`10.9.1
`Case Study: FFT and Inverse FFT
`10.10 Support for Fixed-Point Data
`10.10.1 Case Study: FFT Function
`10.11 Support for Variable-Sized Data
`10.11.1 Case Study: Adaptive Modulation
`10.11.2 Fixed-sized Code Generation
`10.11.3 Bounded Variable-Sized Data
`10.11.4 Unbounded Variable-Sized Data
`10.12 Integration with Existing C/C++ Code
`10.12.1 Algorithm
`10.12.2 Executing MATLAB Testbench
`10.12.3 Generating C Code
`10.12.4 Entry-Point Functions in C
`10.12.5 C Main Function
`10.12.6 Compiling and Linking
`10.12.7 Executing C Testbench
`10.13 Chapter Summary
`References
`
`11.2
`
`Summary
`11
`11.1 Modeling
`Theoretical Considerations
`11.1.1
`Standard Specifications
`11.1.2
`Algorithms in MATLAB®
`11.1.3
`Simulation
`11.2.1
`Simulation Acceleration
`11.2.2
`Acceleration Methods
`11.2.3
`Implementation
`11.3 Directions for Future Work
`11.3.1
`User-Plane Details
`11.3.2
`Control-Plane Processing
`11.3.3
`Hybrid Automatic Repeat Request
`11.3.4
`System-Access Modules
`11.4 Concluding Remarks
`
`Index
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`

`

`Preface
`
`The LTE (Long Term Evolution) and LTE-Advanced are the latest mobile communications
`standards developed by the Third Generation Partnership Project (3GPP). These standards
`represent a transformative change in the evolution of mobile technology. Within the present
`decade, the network infrastructures and mobile terminals have been designed and upgraded to
`support the LTE standards. As these systems are deployed in every corner of the globe, the
`LTE standards have finally realized the dream of providing a truly global broadband mobile
`access technology.
`In this book we will examine the LTE mobile communications standard, and specifically its
`PHY (Physical Layer), in order to understand how and why it can achieve such a remarkable
`feat. We will look at it simultaneously from an academic and a pragmatic point of view. We
`will relate the mathematical foundation of its enabling technologies, such as Orthogonal Fre-
`quency Division Multiplexing (OFDM) and Multiple Input Multiple Output (MIMO), to its
`ability to achieve such a superb performance. We will also show how pragmatic engineering
`considerations have shaped the formulation of many of its components. As an integral part
`of this book, we will use MATLAB®, a technical computing language and simulation envi-
`ronment widely used by the scientific and engineering community, to clarify the mathematical
`concepts and constructs, provide algorithms, testbenches, and illustrations, and give the reader
`a deep understanding of the specifications through the use of simulations.
`This book is written for both the academic community and the practicing professional. It
`focuses specifically on the LTE standard and its evolution. Unlike many titles that treat only
`the mathematical foundation of the standard, this book will discuss the mathematical for-
`mulation of many enabling technologies (such as OFDM and MIMO) in the context of the
`overall performance of the system. Furthermore, by including chapters dedicated to simula-
`tion, performance evaluation, and implementation, the book broadens its appeal to a much
`larger readership composed of both academicians and practitioners.
`Through an intuitive and pedagogic approach, we will build up components of the LTE PHY
`progressively from simple to more complex using MATLAB programs. Through simulation
`of the MATLAB programs, the reader will feel confident that he or she has learned not only
`all the details necessary to fully understand the standard but also the ability to implement it.
`We aim to clarify technical details related to PHY modeling of the LTE standard. There-
`fore, knowledge of the basics of communication theory (topics such as modulation, coding,
`and estimation) and digital signal processing is a prerequisite. These prerequisites are usually
`covered by the senior year of most electrical engineering undergraduate curricula. It also aims
`to teach through simulation with MATLAB. Therefore a basic knowledge of the MATLAB
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`xiv
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`Preface
`
`language is necessary to follow the text. This book is intended for professors, researchers, and
`students in electrical and computer engineering departments, as well as engineers, designers,
`and implementers of wireless systems. What they learn from both a technical and a program-
`ming point of view may be quite applicable to their everyday work. Depending on the reader’s
`function and the need to implement or teach the LTE standard, this book may be considered
`introductory, intermediate, or advanced in nature.
`The book is conceptually composed of two parts. The first deals with modeling the PHY of
`the LTE standard and with MATLAB algorithms that enable the reader to simulate and verify
`various components of the system. The second deals with practical issues such as simulation
`of the system and implementation and prototyping of its components. In the first chapter we
`provide a brief introduction to the standard, its genesis, and its objective, and we identify four
`enabling technologies (OFDM, MIMO, turbo coding, and dynamic link adaptations) as the
`components responsible for its remarkable performance. In Chapter 2, we provide a quick and
`sufficiently detailed overview of the LTE PHY specifications. Chapter 3 introduces the mod-
`eling, simulation, and implementation capabilities of MATLAB and Simulink that are used
`throughout this book. In Chapters 4–7 we treat each of the enabling technologies of the LTE
`standard (modulation and coding, OFDM, MIMO, and link adaptations) in detail and create
`models in MATLAB that iteratively and progressively build up LTE PHY components based
`on these. We wrap up the first part of the book in Chapter 8 by putting all the enabling tech-
`nologies together and showing how the PHY of the LTE standard can be modeled in MATLAB
`based on the insight obtained in the preceding chapters.
`Chapter 9 includes a discussion on how to accelerate the speed of our MATLAB programs
`through the use of a variety of techniques, including parallel computing, automatic C code
`generation, GPU processing, and more efficient algorithms. In Chapter 10 we discuss some
`implementation issues, such as target environments, and how they affect the programming
`style. We also discuss fixed-point numerical representation of data as a prerequisite for hard-
`ware implementation and its effect on the performance of the standard. Finally, in Chapter 11
`we summarize what we have discussed and provide some directions for future work.
`Any effort related to introducing the technical background of a complex communications
`system like LTE requires addressing the question of scope. We identify three conceptual ele-
`ments that can combine to provide a deep understanding of the way the LTE standard works:
`
`• The theoretical background of the enabling technologies
`• Details regarding the standard specifications
`• Algorithms and simulation testbenches needed to implement the design
`
`To make the most of the time available to develop this book, we decided to strike a balance in
`covering each of these conceptual elements. We chose to provide a sufficient level of discussion
`regarding the theoretical foundations and technical specifications of the standard. To leverage
`our expertise in developing MATLAB applications, we decided to cover the algorithms and
`testbenches that implement various modes of the LTE standard in further detail. This choice
`was motivated by two factors:
`
`1. There are many books that extensively cover the first two elements and do not focus on
`algorithms and simulations. We consider the emphasis on simulation one of the innovative
`characteristics of this work.
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`Preface
`
`xv
`
`2. By providing simulation models of the LTE standard, we help the reader develop an under-
`standing of the elements that make up a communications system and obtain a programmatic
`recipe for the sequence of operations that make up the PHY specifications. Algorithms and
`testbenches naturally reveal the dynamic nature of a system through simulation.
`
`In this sense, the insight and understanding obtained by delving into simulation details are
`invaluable as they provide a better mastery of the subject matter. Even more importantly, they
`instill a sense of confidence in the reader that he or she can try out new ideas, propose and test
`new improvements, and make use of new tools and models to help graduate from a theoretical
`knowledge to a hands-on understanding and ultimately to the ability to innovate, design, and
`implement.
`It is our hope that this book can provide a reliable framework for modeling and simulation of
`the LTE standard for the community of young researchers, students, and professionals inter-
`ested in mobile communications. We hope they can apply what they learn here, introduce their
`own improvements and innovations, and become inspired to contribute to the research and
`development of the mobile communications systems of the future.
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`List of Abbreviations
`
`Application-Specific Integrated Circuit
`ASIC
`Broadcast Channel
`BCH
`Bit Error Rate
`BER
`Binary Phase Shift Keying
`BPSK
`Cyclic Prefix
`CP
`Channel Quality Indicator
`CQI
`Cyclic Redundancy Check
`CRC
`Channel State Information
`CSI
`Channel State Information Reference Signal
`CSI-RS
`Cell-Specific Reference
`CSR
`Compute Unified Device Architecture
`CUDA
`Demodulation Reference Signal
`DM-RS
`Digital Signal Processor
`DSP
`enhanced Node Base station
`eNodeB
`Evolved Universal Terrestrial Radio Access
`E-UTRA
`Frequency Division Duplex
`FDD
`Field-Programmable Gate Array
`FPGA
`Hybrid Automatic Repeat Request
`HARQ
`Hardware Description Language
`HDL
`Long Term Evolution
`LTE
`Medium Access Control
`MAC
`Multimedia Broadcast and Multicast Service
`MBMS
`Multicast/Broadcast over Single Frequency Network
`MBSFN
`Multiple Input Multiple Output
`MIMO
`Minimum Mean Square Error
`MMSE
`Maximum Ratio Combining
`MRC
`MU-MIMO Multi-User Multiple Input Multiple Output
`OFDM
`Orthogonal Frequency Division Multiplexing
`PBCH
`Physical Broadcast Channel
`PCFICH
`Physical Control Format Indicator Channel
`PCM
`Pulse Code Modulation
`PDCCH
`Physical Downlink Control Channel
`PDSCH
`Physical Downlink Shared Channel
`PHICH
`Physical Hybrid ARQ Indicator Channel
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`List of Abbreviations
`
`xviii
`
`PHY
`PMCH
`PRACH
`PSS
`PUCCH
`PUSCH
`QAM
`QPP
`QPSK
`RLC
`RMS
`RRC
`RTL
`SC-FDM
`SD
`SFBC
`SINR
`SNR
`SSD
`SSS
`STBC
`SFBC
`SU-MIMO
`TDD
`UE
`ZF
`
`Physical Layer
`Physical Multicast Channel
`Physical Random Access Channel
`Primary Synchronization Signal
`Physical Uplink Control Channel
`Physical Uplink Shared Channel
`Quadrature Amplitude Modulation
`Quadratic Permutation Polynomial
`Quadrature Phase Shift Keying
`Radio Link Control
`Root Mean Square
`Radio Resource Control
`Register Transfer Level
`Single-Carrier Frequency Division Multiplexing
`Sphere Decoder
`Space–Frequency Block Coding
`Signal-to-Interference-plus-Noise Ratio
`Signal-to-Noise Ratio
`Soft-Sphere Decoder
`Secondary Synchronization Signal
`Space–Time Block Coding
`Space-Frequency Block Coding
`Single-User MIMO
`Time-Division Duplex
`User Equipment
`Zero Forcing
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`1 I
`
`ntroduction
`
`We live in the era of a mobile data revolution. With the mass-market expansion of smartphones,
`tablets, notebooks, and laptop computers, users demand services and applications from mobile
`communication systems that go far beyond mere voice and telephony. The growth in data-
`intensive mobile services and applications such as Web browsing, social networking, and
`music and video streaming has become a driving force for development of the next gener-
`ation of wireless standards. As a result, new standards are being developed to provide the
`data rates and network capacity necessary to support worldwide delivery of these types of rich
`multimedia application.
`LTE (Long Term Evolution) and LTE-Advanced have been developed to respond to the
`requirements of this era and to realize the goal of achieving global broadband mobile com-
`munications. The goals and objectives of this evolved system include higher radio access data
`rates, improved system capacity and coverage, flexible bandwidth operations, significantly
`improved spectral efficiency, low latency, reduced operating costs, multi-antenna support, and
`seamless integration with the Internet and existing mobile communication systems.
`In some ways, LTE and LTE-Advanced are representatives of what is known as a fourth-
`generation wireless system and can be considered an organic evolution of the third-generation
`predecessors. On the other hand, in terms of their underlying transmission technology they
`represent a disruptive departure from the past and the dawn of what is to come. To put into
`context the evolution of mobile technology leading up to the introduction of the LTE standards,
`a short overview of the wireless standard history will now be presented. This overview intends
`to trace the origins of many enabling technologies of the LTE standards and to clarify some of
`their requirements, which are expressed in terms of improvements over earlier technologies.
`
`1.1 Quick Overview of Wireless Standards
`In the past two decades we have seen the introduction of various mobile standards, from 2G to
`3G to the present 4G, and we expect the trend to continue (see Figure 1.1). The primary man-
`date of the 2G standards was the support of mobile telephony and voice applications. The 3G
`standards marked the beginning of the packet-based data revolution and the support of Internet
`
`Understanding LTE with MATLAB®: From Mathematical Modeling to Simulation and Prototyping, First Edition.
`Houman Zarrinkoub.
`© 2014 John Wiley & Sons, Ltd. Published 2014 by John Wiley & Sons, Ltd.
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`2
`
`IEEE
`standards
`
`Understanding LTE with MATLAB®
`
`2G
`
`2.5G
`
`3G
`
`3.5G
`
`3.9G
`
`4G ...beyond
`
`802.11a
`
`802.11b
`
`802.11g
`
`802.11n
`
`802.16d
`
`802.16e
`
`European
`standards
`
`GSM
`
`W-
`CDMA
`(UMTS)
`
`HSDPA
`
`GPRS
`
`Edge
`
`HSUPA
`
`North
`American
`standards
`
`IS-54
`
`IS-136
`
`IS-95
`
`CDMA-
`2000
`
`1990
`
`2000
`
`1x-EV
`Do
`
`2004
`
`802.16m
`
`HSPA+
`
`LTE
`
`LTE
`Advanced
`
`2010
`
`time
`
`Figure 1.1 Evolution of wireless standards in the last two decades
`
`applications such as email, Web browsing, text messaging, and other client-server services. The
`4G standards will feature all-IP packet-based networks and will support the explosive demand
`for bandwidth-hungry applications such as mobile video-on-demand services.
`Historically, standards for mobile communication have been developed by consortia of net-
`work providers and operators, separately in North America, Europe, and other regions of the
`world. The second-generation (2G) digital mobile communications systems were introduced
`in the early 1990s. The technology supporting these 2G systems were circuit-switched data
`communications. The GSM (Global System for Mobile Communications) in Europe and the
`IS-54 (Interim Standard 54) in North America were among the first 2G standards. Both were
`based on the Time Division Multiple Access (TDMA) technology. In TDMA, a narrowband
`communication channel is subdivided into a number of time slots and multiple users share the
`spectrum at allocated slots. In terms of data rates, for example, GSM systems support voice
`services up to 13 kbps and data services up to 9.6 kbps.
`The GSM standard later evolved into the Generalized Packet Radio Service (GPRS), sup-
`porting a peak data rate of 171.2 kbps. The GPRS standard marked the introduction of the
`split-core wireless networks, in which packet-based switching technology supports data trans-
`mission and circuit-switched technology supports voice transmission. The GPRS technology
`further evolved into Enhanced Data Rates for Global Evolution (EDGE), which introduced a
`higher-rate modulation scheme (8-PSK, Phase Shift Keying) and further enhanced the peak
`data rate to 384 kbps.
`In North America, the introduction of IS-95 marked the first commercial deployment of a
`Code Division Multiple Access (CDMA) technology. CDMA in IS-95 is based on a direct
`spread spectrum technology, where multiple users share a wider bandwidth by using orthog-
`onal spreading codes. IS-95 employs a 1.2284 MHz bandwidth and allows for a maximum
`of 64 voice channels per cell, with a peak data rate of 14.4 kbps per fundamental channel.
`The IS-95-B revision of the standard was developed to support high-speed packet-based
`data transmission. With the introduction of the new supplemental code channel supporting
`high-speed packet data, IS-95-B supported a peak data rate of 115.2 kbps. In North America,
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`Introduction
`
`3
`
`3GPP2 (Third Generation Partnership Project 2) was the standardization body that established
`technical specifications and standards for 3G mobile systems based on the evolution of CDMA
`technology. From 1997 to 2003, 3GPP2 developed a family of standards based on the original
`IS-95 that included 1xRTT, 1x-EV-DO (Evolved Voice Data Only), and EV-DV (Evolved
`Data and Voice). 1xRTT doubled the IS-95 capacity by adding 64 more traffic channels to
`achieve a peak data rate of 307 kbps. The 1x-EV-DO and 1x-EV-DV standards achieved peak
`data rates in the range of 2.4–3.1 Mbps by introducing a set of features including adaptive
`modulation and coding, hybrid automatic repeat request (HARQ), turbo coding, and faster
`scheduling based on smaller frame sizes.
`The 3GPP (Third-Generation Partnership Project) is the standardization body that originally
`managed European mobile standard and later on evolved into a global standardization organi-
`zation. It is responsible for establishing technical specifications for the 3G mobile systems and
`beyond. In 1997, 3GPP started working on a standardization effort to meet goals specified by
`the ITU IMT-2000 (International Telecommunications Union International Mobile Telecom-
`munication) project. The goal of this project was the transition from a 2G TDMA-based
`GSM technology to a 3G wide-band CDMA-based technology called the Universal Mobile
`Telecommunications System (UMTS). The UMTS represented a significant change in mobile
`communications at the time. It was standardized in 2001 and was dubbed Release 4 of the
`3GPP standards. The UMTS system can achieve a downlink peak data rate of 1.92 Mbps. As
`an upgrade to the UMTS system, the High-Speed Downlink Packet Access (HSDPA) was
`standardized in 2002 as Release 5 of the 3GPP. The peak data rates of 14.4 Mbps offered by
`this standard were made possible by introducing faster scheduling with shorter subframes and
`the use of a 16QAM (Quadrature Amplitude Modulation) modulation scheme. High-Speed
`Uplink Packet Access (HSUPA) was standardized in 2004 as Release 6, with a maximum rate
`of 5.76 Mbps. Both of these standards, together known as HSPA (High-Speed Packet Access),
`were then upgraded to Release 7 of the 3GPP standard known as HSPA+ or MIMO (Multiple
`Input Multiple Output) HSDPA. The HSPA+ standard can reach rates of up to 84 Mbps and
`was the first mobile standard to introduce a 2 × 2 MIMO technique and the use of an even
`higher modulation scheme (64QAM). Advanced features that were originally introduced as
`part of the North American 3G standards were also incorporated in HSPA and HSPA+. These
`features include adaptive modulation and coding, HARQ, turbo coding, and faster scheduling.
`Another important wireless application that has been a driving force for higher data rates
`and spectral efficiency is the wireless local area network (WLAN). The main purpose of
`WLAN standards is to provide stationary users in buildings (homes, offices) with reliable
`and high-speed network connections. As the global mobile communications networks were
`undergoing their evolution, IEEE