Tài liệu @mimo ofdm wireless communications with matlab

MIMO-OFDM WIRELESS COMMUNICATIONS WITH MATLABÒ MIMO-OFDM WIRELESS COMMUNICATIONS WITH MATLABÒ Yong Soo Cho Chung-Ang University, Republic of Korea Jaekwon Kim Yonsei University, Republic of Korea Won Young Yang Chung-Ang University, Republic of Korea Chung G. Kang Korea University, Republic of Korea Copyright Ó 2010 John Wiley & Sons (Asia) Pte Ltd, 2 Clementi Loop, # 02-01, Singapore 129809 Visit our Home Page on www.wiley.com 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, scanning, or otherwise, except as expressly permitted by law, without either the prior written permission of the Publisher, or authorization through payment of the appropriate photocopy fee to the Copyright Clearance Center. 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Other Wiley Editorial Offices John Wiley & Sons, Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK John Wiley & Sons Inc., 111 River Street, Hoboken, NJ 07030, USA Jossey-Bass, 989 Market Street, San Francisco, CA 94103-1741, USA Wiley-VCH Verlag GmbH, Boschstrasse 12, D-69469 Weinheim, Germany John Wiley & Sons Australia Ltd, 42 McDougall Street, Milton, Queensland 4064, Australia John Wiley & Sons Canada Ltd, 5353 Dundas Street West, Suite 400, Toronto, ONT, M9B 6H8, Canada Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. Library of Congress Cataloging-in-Publication Data MIMO-OFDM wireless communications with MATLABÒ / Yong Soo Cho ... [et al.]. p. cm. Includes bibliographical references and index. ISBN 978-0-470-82561-7 (cloth) 1. Orthogonal frequency division multiplexing. 2. MIMO systems. 3. MATLABÒ. I. Cho, Yong Soo. TK5103.484.M56 2010 621.384–dc22 2010013156 Print ISBN: 978-0-470-82561-7 ePDF ISBN: 978-0-470-82562-4 oBook ISBN: 978-0-470-82563-1 Typeset in 10/12pt Times by Thomson Digital, Noida, India. This book is printed on acid-free paper responsibly manufactured from sustainable forestry in which at least two trees are planted for each one used for paper production. To our parents and families who love and support us and to our students who enriched our knowledge Contents Preface xiii Limits of Liability and Disclaimer of Warranty of Software xv 1 The Wireless Channel: Propagation and Fading 1.1 Large-Scale Fading 1.1.1 General Path Loss Model 1.1.2 Okumura/Hata Model 1.1.3 IEEE 802.16d Model 1.2 Small-Scale Fading 1.2.1 Parameters for Small-Scale Fading 1.2.2 Time-Dispersive vs. Frequency-Dispersive Fading 1.2.3 Statistical Characterization and Generation of Fading Channel 1 4 4 8 10 15 15 16 2 SISO Channel Models 2.1 Indoor Channel Models 2.1.1 General Indoor Channel Models 2.1.2 IEEE 802.11 Channel Model 2.1.3 Saleh-Valenzuela (S-V) Channel Model 2.1.4 UWB Channel Model 2.2 Outdoor Channel Models 2.2.1 FWGN Model 2.2.2 Jakes Model 2.2.3 Ray-Based Channel Model 2.2.4 Frequency-Selective Fading Channel Model 2.2.5 SUI Channel Model 25 25 26 28 30 35 40 41 50 54 61 65 3 MIMO Channel Models 3.1 Statistical MIMO Model 3.1.1 Spatial Correlation 3.1.2 PAS Model 3.2 I-METRA MIMO Channel Model 3.2.1 Statistical Model of Correlated MIMO Fading Channel 3.2.2 Generation of Correlated MIMO Channel Coefficients 71 71 73 76 84 84 88 19 viii Contents 3.3 4 3.2.3 3.2.4 SCM 3.3.1 3.3.2 3.3.3 I-METRA MIMO Channel Model 3GPP MIMO Channel Model MIMO Channel Model SCM Link-Level Channel Parameters SCM Link-Level Channel Modeling Spatial Correlation of Ray-Based Channel Model 90 94 97 98 102 105 Introduction to OFDM 4.1 Single-Carrier vs. Multi-Carrier Transmission 4.1.1 Single-Carrier Transmission 4.1.2 Multi-Carrier Transmission 4.1.3 Single-Carrier vs. Multi-Carrier Transmission 4.2 Basic Principle of OFDM 4.2.1 OFDM Modulation and Demodulation 4.2.2 OFDM Guard Interval 4.2.3 OFDM Guard Band 4.2.4 BER of OFDM Scheme 4.2.5 Water-Filling Algorithm for Frequency-Domain Link Adaptation 4.3 Coded OFDM 4.4 OFDMA: Multiple Access Extensions of OFDM 4.4.1 Resource Allocation – Subchannel Allocation Types 4.4.2 Resource Allocation – Subchannelization 4.5 Duplexing 111 111 111 115 120 121 121 126 132 136 5 Synchronization for OFDM 5.1 Effect of STO 5.2 Effect of CFO 5.2.1 Effect of Integer Carrier Frequency Offset (IFO) 5.2.2 Effect of Fractional Carrier Frequency Offset (FFO) 5.3 Estimation Techniques for STO 5.3.1 Time-Domain Estimation Techniques for STO 5.3.2 Frequency-Domain Estimation Techniques for STO 5.4 Estimation Techniques for CFO 5.4.1 Time-Domain Estimation Techniques for CFO 5.4.2 Frequency-Domain Estimation Techniques for CFO 5.5 Effect of Sampling Clock Offset 5.5.1 Effect of Phase Offset in Sampling Clocks 5.5.2 Effect of Frequency Offset in Sampling Clocks 5.6 Compensation for Sampling Clock Offset 5.7 Synchronization in Cellular Systems 5.7.1 Downlink Synchronization 5.7.2 Uplink Synchronization 153 153 156 159 160 162 162 168 170 170 173 177 177 178 178 180 180 183 6 Channel Estimation 6.1 Pilot Structure 6.1.1 Block Type 187 187 187 139 142 143 145 146 150 ix Contents 6.2 6.3 6.4 6.5 6.1.2 Comb Type 6.1.3 Lattice Type Training Symbol-Based Channel Estimation 6.2.1 LS Channel Estimation 6.2.2 MMSE Channel Estimation DFT-Based Channel Estimation Decision-Directed Channel Estimation Advanced Channel Estimation Techniques 6.5.1 Channel Estimation Using a Superimposed Signal 6.5.2 Channel Estimation in Fast Time-Varying Channels 6.5.3 EM Algorithm-Based Channel Estimation 6.5.4 Blind Channel Estimation 188 189 190 190 191 195 199 199 199 201 204 206 7 PAPR Reduction 7.1 Introduction to PAPR 7.1.1 Definition of PAPR 7.1.2 Distribution of OFDM Signal 7.1.3 PAPR and Oversampling 7.1.4 Clipping and SQNR 7.2 PAPR Reduction Techniques 7.2.1 Clipping and Filtering 7.2.2 PAPR Reduction Code 7.2.3 Selective Mapping 7.2.4 Partial Transmit Sequence 7.2.5 Tone Reservation 7.2.6 Tone Injection 7.2.7 DFT Spreading 209 209 210 216 218 222 224 224 231 233 234 238 239 241 8 Inter-Cell Interference Mitigation Techniques 8.1 Inter-Cell Interference Coordination Technique 8.1.1 Fractional Frequency Reuse 8.1.2 Soft Frequency Reuse 8.1.3 Flexible Fractional Frequency Reuse 8.1.4 Dynamic Channel Allocation 8.2 Inter-Cell Interference Randomization Technique 8.2.1 Cell-Specific Scrambling 8.2.2 Cell-Specific Interleaving 8.2.3 Frequency-Hopping OFDMA 8.2.4 Random Subcarrier Allocation 8.3 Inter-Cell Interference Cancellation Technique 8.3.1 Interference Rejection Combining Technique 8.3.2 IDMA Multiuser Detection 251 251 251 254 255 256 257 257 258 258 260 260 260 262 9 MIMO: Channel Capacity 9.1 Useful Matrix Theory 9.2 Deterministic MIMO Channel Capacity 263 263 265 x Contents 9.2.1 9.3 Channel Capacity when CSI is Known to the Transmitter Side 9.2.2 Channel Capacity when CSI is Not Available at the Transmitter Side 9.2.3 Channel Capacity of SIMO and MISO Channels Channel Capacity of Random MIMO Channels 266 270 271 272 10 Antenna Diversity and Space-Time Coding Techniques 10.1 Antenna Diversity 10.1.1 Receive Diversity 10.1.2 Transmit Diversity 10.2 Space-Time Coding (STC): Overview 10.2.1 System Model 10.2.2 Pairwise Error Probability 10.2.3 Space-Time Code Design 10.3 Space-Time Block Code (STBC) 10.3.1 Alamouti Space-Time Code 10.3.2 Generalization of Space-Time Block Coding 10.3.3 Decoding for Space-Time Block Codes 10.3.4 Space-Time Trellis Code 281 281 283 287 287 287 289 292 294 294 298 302 307 11 Signal Detection for Spatially Multiplexed MIMO Systems 11.1 Linear Signal Detection 11.1.1 ZF Signal Detection 11.1.2 MMSE Signal Detection 11.2 OSIC Signal Detection 11.3 ML Signal Detection 11.4 Sphere Decoding Method 11.5 QRM-MLD Method 11.6 Lattice Reduction-Aided Detection 11.6.1 Lenstra-Lenstra-Lovasz (LLL) Algorithm 11.6.2 Application of Lattice Reduction 11.7 Soft Decision for MIMO Systems 11.7.1 Log-Likelihood-Ratio (LLR) for SISO Systems 11.7.2 LLR for Linear Detector-Based MIMO System 11.7.3 LLR for MIMO System with a Candidate Vector Set 11.7.4 LLR for MIMO System Using a Limited Candidate Vector Set Appendix 11.A Derivation of Equation (11.23) 319 319 320 321 322 327 329 339 344 345 349 352 353 358 361 12 Exploiting Channel State Information at the Transmitter Side 12.1 Channel Estimation on the Transmitter Side 12.1.1 Using Channel Reciprocity 12.1.2 CSI Feedback 12.2 Precoded OSTBC 364 370 373 373 374 374 375 Contents xi 12.3 Precoded Spatial-Multiplexing System 12.4 Antenna Selection Techniques 12.4.1 Optimum Antenna Selection Technique 12.4.2 Complexity-Reduced Antenna Selection 12.4.3 Antenna Selection for OSTBC 381 383 384 386 390 13 Multi-User MIMO 13.1 Mathematical Model for Multi-User MIMO System 13.2 Channel Capacity of Multi-User MIMO System 13.2.1 Capacity of MAC 13.2.2 Capacity of BC 13.3 Transmission Methods for Broadcast Channel 13.3.1 Channel Inversion 13.3.2 Block Diagonalization 13.3.3 Dirty Paper Coding (DPC) 13.3.4 Tomlinson-Harashima Precoding 395 396 397 398 399 401 401 404 408 412 References 419 Index 431 Preface MIMO-OFDM is a key technology for next-generation cellular communications (3GPP-LTE, Mobile WiMAX, IMT-Advanced) as well as wireless LAN (IEEE 802.11a, IEEE 802.11n), wireless PAN (MB-OFDM), and broadcasting (DAB, DVB, DMB). This book provides a comprehensive introduction to the basic theory and practice of wireless channel modeling, OFDM, and MIMO, with MATLABÒ programs to simulate the underlying techniques on MIMO-OFDM systems. This book is primarily designed for engineers and researchers who are interested in learning various MIMO-OFDM techniques and applying them to wireless communications. It can also be used as a textbook for graduate courses or senior-level undergraduate courses on advanced digital communications. The readers are assumed to have a basic knowledge on digital communications, digital signal processing, communication theory, signals and systems, as well as probability and random processes. The first aim of this book is to help readers understand the concepts, techniques, and equations appearing in the field of MIMO-OFDM communication, while simulating various techniques used in MIMO-OFDM systems. Readers are recommended to learn some basic usage of MATLABÒ that is available from the MATLABÒ help function or the on-line documents at the website www.mathworks.com/matlabcentral. However, they are not required to be an expert on MATLABÒ since most programs in this book have been composed carefully and completely, so that they can be understood in connection with related/referred equations. The readers are expected to be familiar with the MATLABÒ software while trying to use or modify the MATLABÒ codes. The second aim of this book is to make even a novice at both MATLABÒ and MIMO-OFDM become acquainted with MIMO-OFDM as well as MATLABÒ, while running the MATLABÒ program on his/her computer. The authors hope that this book can be used as a reference for practicing engineers and students who want to acquire basic concepts and develop an algorithm on MIMO-OFDM using the MATLABÒ program. The features of this book can be summarized as follows: . . . Part I presents the fundamental concepts and MATLABÒ programs for simulation of wireless channel modeling techniques, including large-scale fading, small-scale fading, indoor and outdoor channel modeling, SISO channel modeling, and MIMO channel modeling. Part II presents the fundamental concepts and MATLABÒ programs for simulation of OFDM transmission techniques including OFDM basics, synchronization, channel estimation, peak-to-average power ratio reduction, and intercell interference mitigation. Part III presents the fundamental concepts and MATLABÒ programs for simulation of MIMO techniques including MIMO channel capacity, space diversity and space-time codes, xiv Preface signal detection for spatially-multiplexed MIMO systems, precoding and antenna selection techniques, and multiuser MIMO systems. Most MATLABÒ programs are presented in a complete form so that the readers with no programming skill can run them instantly and focus on understanding the concepts and characteristics of MIMO-OFDM systems. The contents of this book are derived from the works of many great scholars, engineers, researchers, all of whom are deeply appreciated. We would like to thank the reviewers for their valuable comments and suggestions, which contribute to enriching this book. We would like to express our heartfelt gratitude to colleagues and former students who developed source programs: Dr. Won Gi Jeon, Dr. Kyung-Won Park, Dr. Mi-Hyun Lee, Dr. Kyu-In Lee, and Dr. Jong-Ho Paik. Special thanks should be given to Ph.D candidates who supported in preparing the typescript of the book: Kyung Soo Woo, Jung-Wook Wee, Chang Hwan Park, Yeong Jun Kim, Yo Han Ko, Hyun Il Yoo, Tae Ho Im, and many MS students in the Digital Communication Lab at Chung-Ang University. We also thank the editorial and production staffs, including Ms. Renee Lee of John Wiley & Sons (Asia) Pte Ltd and Ms. Aparajita Srivastava of Thomson Digital, for their kind, efficient, and encouraging guidance. Program files can be downloaded from http://comm.cau.ac.kr/MIMO_OFDM/index.html. Limits of Liability and Disclaimer of Warranty of Software The authors and publisher of this book have used their best efforts and knowledge in preparing this book as well as developing the computer programs in it. However, they make no warranty of any kind, expressed or implied, with regard to the programs or the documentation contained in this book. Accordingly, they shall not be liable for any incidental or consequential damages in connection with, or arising out of, the readers’ use of, or reliance upon, the material in this book. The reader is expressly warned to consider and adopt all safety precautions that might be indicated by the activities herein and to avoid all potential hazards. By following the instructions contained herein, the reader willingly assumes all risks in connection with such instructions. 1 The Wireless Channel: Propagation and Fading The performance of wireless communication systems is mainly governed by the wireless channel environment. As opposed to the typically static and predictable characteristics of a wired channel, the wireless channel is rather dynamic and unpredictable, which makes an exact analysis of the wireless communication system often difficult. In recent years, optimization of the wireless communication system has become critical with the rapid growth of mobile communication services and emerging broadband mobile Internet access services. In fact, the understanding of wireless channels will lay the foundation for the development of high performance and bandwidth-efficient wireless transmission technology. In wireless communication, radio propagation refers to the behavior of radio waves when they are propagated from transmitter to receiver. In the course of propagation, radio waves are mainly affected by three different modes of physical phenomena: reflection, diffraction, and scattering [1,2]. Reflection is the physical phenomenon that occurs when a propagating electromagnetic wave impinges upon an object with very large dimensions compared to the wavelength, for example, surface of the earth and building. It forces the transmit signal power to be reflected back to its origin rather than being passed all the way along the path to the receiver. Diffraction refers to various phenomena that occur when the radio path between the transmitter and receiver is obstructed by a surface with sharp irregularities or small openings. It appears as a bending of waves around the small obstacles and spreading out of waves past small openings. The secondary waves generated by diffraction are useful for establishing a path between the transmitter and receiver, even when a line-of-sight path is not present. Scattering is the physical phenomenon that forces the radiation of an electromagnetic wave to deviate from a straight path by one or more local obstacles, with small dimensions compared to the wavelength. Those obstacles that induce scattering, such as foliage, street signs, and lamp posts, are referred to as the scatters. In other words, the propagation of a radio wave is a complicated and less predictable process that is governed by reflection, diffraction, and scattering, whose intensity varies with different environments at different instances. A unique characteristic in a wireless channel is a phenomenon called ‘fading,’ the variation of the signal amplitude over time and frequency. In contrast with the additive noise as the most MIMO-OFDM Wireless Communications with MATLAB
Yong Soo Cho, Jaekwon Kim, Won Young Yang and Chung G. Kang  2010 John Wiley & Sons (Asia) Pte Ltd MIMO-OFDM Wireless Communications with MATLAB
2 common source of signal degradation, fading is another source of signal degradation that is characterized as a non-additive signal disturbance in the wireless channel. Fading may either be due to multipath propagation, referred to as multi-path (induced) fading, or to shadowing from obstacles that affect the propagation of a radio wave, referred to as shadow fading. The fading phenomenon in the wireless communication channel was initially modeled for HF (High Frequency, 3
30 MHz), UHF (Ultra HF, 300
3000 GHz), and SHF (Super HF, 3
30 GHz) bands in the 1950s and 1960s. Currently, the most popular wireless channel models have been established for 800MHz to 2.5 GHz by extensive channel measurements in the field. These include the ITU-R standard channel models specialized for a single-antenna communication system, typically referred to as a SISO (Single Input Single Output) communication, over some frequency bands. Meanwhile, spatial channel models for a multi-antenna communication system, referred to as the MIMO (Multiple Input Multiple Output) system, have been recently developed by the various research and standardization activities such as IEEE 802, METRA Project, 3GPP/3GPP2, and WINNER Projects, aiming at high-speed wireless transmission and diversity gain. The fading phenomenon can be broadly classified into two different types: large-scale fading and small-scale fading. Large-scale fading occurs as the mobile moves through a large distance, for example, a distance of the order of cell size [1]. It is caused by path loss of signal as a function of distance and shadowing by large objects such as buildings, intervening terrains, and vegetation. Shadowing is a slow fading process characterized by variation of median path loss between the transmitter and receiver in fixed locations. In other words, large-scale fading is characterized by average path loss and shadowing. On the other hand, small-scale fading refers to rapid variation of signal levels due to the constructive and destructive interference of multiple signal paths (multi-paths) when the mobile station moves short distances. Depending on the relative extent of a multipath, frequency selectivity of a channel is characterized (e.g., by frequency-selective or frequency flat) for small-scaling fading. Meanwhile, depending on the time variation in a channel due to mobile speed (characterized by the Doppler spread), shortterm fading can be classified as either fast fading or slow fading. Figure 1.1 classifies the types of fading channels. Fading channel Large-scale fading Path loss Shadowing Frequency-selective fading Small-scale fading Multi-path fading Time variance Flat fading Fast fading Figure 1.1 Classification of fading channels. Slow fading