WPMC2009 Tutorials

1. “Beyond 3G: Technical Overview of 3GPP Long Term Evolution (LTE) and WiMAX”

Dr. Hyung G. Myung
Qualcomm / Flarion Technologies, USA

Abstract

The current 3rd generation cellular wireless systems are evolving into 4th generation. As a pathway to 4G, 3GPP is currently developing Long Term Evolution (LTE) standard and IEEE 802.16-based WiMAX is also gaining attention as a 4G solution. In terms of air interface techniques, both systems use OFDMA-based multicarrier modulation, multi-input multi-output (MIMO) techniques, and other advanced features to greatly improve the mobile wireless services. In this tutorial, we first survey the underlying techniques of the beyond-3G systems such as OFDMA, SC-FDMA, MIMO, fractional frequency reuse (FFR), and fast multi-carrier resource scheduling. Then, we give technical overview of 3GPP LTE and WiMAX. Specifically, we describe the system architecture, physical layer, and MAC layer of each system.

Outline:
• Introduction and Background
• Key Beyond-3G Technologies: OFDMA, SC-FDMA, MIMO, FFR, and Multi-Carrier Scheduling
• Overview of 3GPP LTE
• Overview of WiMAX
• Comparison of LTE and WiMAX
• Conclusions

Biography

Hyung G. Myung is currently with Qualcomm/Flarion Technologies, Bridgewater, NJ. He received the B.S. and M.S. degrees in electronics engineering from Seoul National University, South Korea in 1994 and in 1996, respectively, and the M.S. degree in applied mathematics from Santa Clara University, California in 2002. He received his Ph.D. degree from the Electrical and Computer Engineering Department of Polytechnic University, Brooklyn, NY in January of 2007. From 1996 to 1999, he served in the Republic of Korea Air Force as a lieutenant officer, and from 1997 to 1999, he was with Department of Electronics Engineering at Republic of Korea Air Force Academy as a faculty member. From 2001 to 2003, he was with ArrayComm, San Jose, CA as a software engineer. During the summer of 2005, he was an assistant research staff at Communication & Networking Lab of Samsung Advanced Institute of Technology. Also from February to August of 2006, he was an intern at Air Interface Group of InterDigital Communications, Melville, NY. His research interests include DSP for communications and wireless communications.

2. “Cognitive Radio Networking and Communications”

Dr. Ying-Chang Liang
Institute for Infocomm Research, Singapore

Intended Audience

Researchers, Students, Engineers, Spectrum Regulators, …

Abstract

Access to radio spectrum today is largely based on fixed spectrum management and allocation. With the proliferation of wireless applications/services in the last couple of decades, in many countries, most of the available spectrum has been allocated. This results in the radio spectrum scarcity which poses a serious problem for the future development of the wireless communications industry. On the other hand, careful studies of the usage pattern reveal that most of the allocated spectrum experiences low utilization. This motivates the concept of opportunistic spectrum access using cognitive radio technology, which allows secondary users to reuse the unused radio spectrum from primary users.

In a generalized sense, the cognitive radio is an intelligent wireless communication system which is aware of the radio frequency environment, selects the communication parameters (such as carrier frequency, bandwidth and transmission power) to optimize the spectrum usage, and then adapts its transmission and reception accordingly. Dynamic spectrum access can generate tremendous economic benefits to both telecom operators and customers through reusing the unused or underutilized spectrum. While economically promising, the success of cognitive radio technology depends on the interdisciplinary research and effort from signal processing, communication theory, information theory, game theory as well as computer vision/intelligence societies.
In this tutorial, we will provide a state-of-art overview on cognitive radio and dynamic spectrum access, covering the theoretical aspects, practical applications and technical challenges. In particular, the following topics will be covered in details.

1. Cognitive radio basics and models
2. Cooperative spectrum sensing
3. Sensing-throughput tradeoff and cognitive medium access control
4. Resource allocation for dynamic spectrum access schemes
5. Exploiting multiple antennas for spectrum sharing
6. Cognitive radio applications

Biography

Dr. Ying-Chang Liang is now Senior Scientist in the Institute for Infocomm Research (I2R), Singapore, where he has been leading the research activities in the area of cognitive radio and cooperative communications and the standardization activities in IEEE 802.22 wireless regional networks (WRAN) for which his team has made fundamental contributions in physical layer, MAC layer and spectrum sensing solutions. He also holds adjunct associate professorship positions in Nanyang Technological University (NTU) and National University of Singapore (NUS), both in Singapore, and adjunct professorship position with University of Electronic Science & Technology of China (UESTC). He has been teaching graduate courses in NUS since 2004. From Dec 2002 to Dec 2003, Dr. Liang was a visiting scholar with the Department of Electrical Engineering, Stanford University. His research interest includes cognitive radio, dynamic spectrum access, reconfigurable signal processing for broadband communications, space-time wireless communications, wireless networking, information theory and statistical signal processing.

Dr. Liang is now an Associate Editor of IEEE Transactions on Vehicular Technology. He was an Associate Editor of IEEE Transactions on Wireless Communications from 2002 to 2005, Lead Guest-Editor of IEEE Journal on Selected Areas in Communications, Special Issue on Cognitive Radio: Theory and Applications, and Guest-Editor of COMPUTER NETWORKS Journal (Elsevier) Special Issue on Cognitive Wireless Networks. He received the Best Paper Awards from IEEE VTC-Fall’1999 and IEEE PIMRC’2005, and 2007 Institute of Engineers Singapore (IES) Prestigious Engineering Achievement Award. Dr. Liang has served for various IEEE conferences as technical program committee (TPC) member. He was Publication Chair of 2001 IEEE Workshop on Statistical Signal Processing, TPC Co-Chair of 2006 IEEE International Conference on Communication Systems (ICCS’2006), Panel Co-Chair of 2008 IEEE Vehicular Technology Conference Spring (VTC’2008-Spring), TPC Co-Chair of 3rd International Conference on Cognitive Radio Oriented Wireless Networks and Communications (CrownCom’2008), TPC Chair of 2010 IEEE Symposium on New Frontiers in Dynamic Spectrum Access Networks (DySPAN’2010), and Co-Chair, Thematic Program on Random matrix theory and its applications in statistics and wireless communications, Institute for Mathematical Sciences, National University of Singapore, 2006. Dr. Liang is a Senior Member of IEEE. He holds six granted patents and more than 15 filed patents.

3. “Wavelets for Cognitive Radio”

Dr. H. Nikookar
Delft University of Technology, The Netherlands

Abstract

Wireless interoperable communication networks are now a reality. They have spawned many new and exciting applications like mobile entertainment, mobile internet access, healthcare and medical monitoring services, data sensing in sensor networks, smart homes, combat radios, disaster management, automated highways and factories. With each passing day newer and newer such services are being launched even while existing services continue to flourish. Demand for wireless services is therefore likely to continue for the foreseeable future. However, with increasing popularity of the wireless services the demands on prime resources like battery power and radio spectrum are put to great test. For example, currently most spectrum has been allocated, and it is becoming increasingly difficult to find frequency bands that can be made available either for new services or to expand existing ones. Even while available frequency bands appear to be fully occupied, a FCC study conducted in 2002 revealed that much of the available spectrum is underused most of the time (only 20 % or less of the spectrum is used) and that spectrum congestions are more due to the sub-optimal use of spectrum than to the lack of free spectrum.

Furthermore, wireless systems frequently have to contend with disruption of services due to interference. Interferences can be due to many reasons – unintentional, intentional (Jamming), overlap of symbols due to temporal spreading (Inter-symbol interference or ISI), adjacent channel interference (Inter-channel interference or ICI), and multiple access interference, posing many challenges in system design and construction. Thus in a wireless environment the system requirements, network and device capabilities have enormous variations giving rise to significant network design challenges.

The design of an intelligent communication system that estimates the channel and adaptively reconfigures to maximize resource utilization and interference mitigation is therefore highly desirable. Cognitive Radio (CR) is an effort in that direction. They are wireless systems that intelligently adapt their transmission parameters (including frequency, power, and modulation scheme) in accordance with the changing environment and requirements.

Multi-carrier modulation (MCM) has been mooted as a strong candidate for CR implementation. By merely vacating a set of subcarriers, the spectrum of a MCM based CR can be easily and flexibly shaped to occupy spectral gaps without interfering with the licensed user (LU). It has been shown that adaptive MCM based CR is a robust method to achieve good quality of communication and efficient use of the spectrum. Traditionally the Fast Fourier transforms (FFT) based orthogonal frequency division multiplexing (OFDM) has been recognized as the most cost-effective realization of multicarrier transceivers. In addition, it has been noted that the FFT as part of the OFDM demodulator can be used for spectral analysis, to identify the presence/absence of the active LUs. This way the spectrum sensing can be performed at virtually no computational cost.

Wavelet transformation has recently emerged as a strong candidate for digital modulation. The wavelet transform is a multi-resolution analysis mechanism where an input signal is decomposed into different frequency components, and then each component is studied with resolutions matched to its scales. It is used in various applications and is finding tremendous popularity among technologists, engineers and mathematicians alike. In most of the applications, the power of the transform comes from the fact that the basis functions of the transform are localized in time (or space) and frequency, and have different resolutions in these domains. With the strict demands of designing Cognitive systems one is therefore entitled to wonder about the possible improvements that advanced schemes such as wavelet- based systems could bring compared to the conventional configurations.

Wavelet Multi-carrier modulation (W-MCM) is a novel transmission technique and a promising alternative to the well established OFDM. The greatest motivation for pursuing W-MCM systems lies in the freedom they provide to communication systems designers. Unlike the Fourier bases which are static sines/cosines, W-MCM uses wavelets which offer flexibility and adaptation that can be tailored to satisfy an engineering demand. By tailoring the design specifications a wavelet based system that best suits an engineering requirement could be conceived. Furthermore a number of shortcomings of OFDM in the application of CR have been noted. The shortcomings originate from the large side-lobes of the frequency response of the filters that characterize the subcarrier channels. These side-lobes, in turn, result in significant out-of-band mutual interference.

In this tutorial we review different wavelet based multicarrier communication methods for the physical layer of cognitive radio systems. Herein, we introduce filterbanks for multicarrier communication and spectral analysis in a CR setting and discuss its performance. A review of the latest advancements and developments in the use of wavelets for cognitive radio is provided. Novel wavelet based MCM techniques that allow for significant increases in wireless capacity with good interference mitigation capabilities will be elucidated. The applications are categorized into two broad domains namely – spectral sensing and spectrum shaping and modulation. The purpose of the half-day tutorial is to disseminate basic knowledge on the current status of research on wavelets based MCM towards their applicability to cognitive radio systems and stimulate novel theoretical and methodological research direction in the field of radio communication. It is aimed to acquaint students, researchers and industry personnel with this exciting field of research, and to highlight possible applications to different cognitive radio domains. The tutorial targets Graduate students, researchers, as well as practicing Engineers from Industry, and is designed to give participants both theoretical and practical skills for fruitful research and development in the field.

The following topics will be covered in this tutorial:
– A short theory of wavelet representation:
    – Time-Frequency analysis,
    – Wavelets and Wavelet Packets,
    – Filter banks,
    – Multi-resolution analysis.
– Motivation for using wavelets for Cognitive Radio.
– Important properties of wavelets for Cognitive Radio system design perspective.
    – Review of applications of Wavelet based Multicarrier modulation system in Cognitive Radio domains:
    – Spectrum sensing
– Spectrum shaping and adaptive power loading
– Design of Wavelets – An Example for Cognitive Radio
– Future Vision – Wavelet Radio: Smart, Adaptive and Reconfigurable Wireless Systems based on Wavelets.

Biography

Homayoun Nikookar received his Ph.D. in Electrical Engineering from Delft University of Technology (TUDelft), The Netherlands, in 1995. He is an Associate Professor at the International Research Centre for Telecommunications and Radar (IRCTR) of the Department of Electrical Engineering, Mathematics and Computer Science of TUDelft. He is also the leader of the Radio Advanced Technologies and Systems (RATS) program of IRCTR, leading a team of researchers carrying out cutting edge research in the field of radio transmission. He has conducted active research in many areas of wireless communications, including wireless channel modeling, UWB, MIMO, multicarrier transmission, Wavelet-based OFDM and Cognitive Radio. He is the co-recipient of the 2000 IEEE Neal Shepherd Best Propagation Paper Award for publication in the March issue of Transactions on Vehicular Technology. He is also recipient of several paper awards of International Conferences and Symposiums. In 2007 Dr. Nikookar served as the Chair of the 14th IEEE Symposium on Communications and Vehicular Technology (SCVT) in Benelux and in 2008 was the Chairman of the European Wireless Technology Conference (EuWiT).

His recent paper, together with I.Budiarjo and L.Ligthart (Cognitive Radio Modulation Techniques, IEEE Signal Processing Magazine, Nov. 2008) has been listed in the IEEE Xplore top 100 documents accessed in Jan. and Feb. 2009. Dr. Nikookar is a Senior Member of the IEEE and the coauthor of the book, Introduction to Ultra Wideband for Wireless Communications, Springer, 2009.

4. “Standardization Activities on Cognitive Radio Systems”

Dr. Hitoshi Yoshino
Softbank Mobile Corporation, Japan

Dr. Hiroshi Harada
National Institute of Information and Communications Technology, Japan

Abstract

Cognitive radio is an emerging technology to further improve spectrum efficiency on an opportunistic basis. Due to the nature of the technology, it has many facets, including its enabling technologies, its implementation issues and its regulatory implications. In ITU-R, cognitive radio systems are currently being studied so that ITU-R can have a clear picture on this new technology and its potential regulatory implications, from a viewpoint of global spectrum management. On the other hand, IEEE SCC41 examines the technical aspects of the cognitive radio systems with a view to developing technical standards on cognitive radio systems.

This tutorial discusses the ongoing standardization activities on Cognitive radio systems both in ITU-R and IEEE and also gives their future perspectives.

List of topics:
1. The standardization activities within ITU-R WP1B (regulatory aspects) and WP5A(technical aspects), including ITU-R structure, work items and potential outcomes on cognitive radio systems, (Yoshino),
2. ITU-R WRC-11 agenda item on cognitive radio systems and its background, (Yoshino),
3. Future perspectives on the ITU-R activities on cognitive radio systems (Yoshino),
4. IEEE structure for cognitive radio standardization, including SCC41 and P.1900.x series, and the background of the establishment of the fora (Harada),
5. Current work items and potential outcomes in each work group (Harada),
6. Future perspectives on the IEEE activities (Harada).

Biography

Hitoshi Yoshino received the B.S. and M.S. degrees in electrical engineering from the Science University of Tokyo, Tokyo, Japan, in 1986 and 1988, respectively, and the Dr. Eng. degree in Communications and Integrated Systems from the Tokyo Institute of Technology, Tokyo, Japan in 2003.

From 1988 to 1992, he was with Radio Communication Systems Laboratories, Nippon Telegraph and Telephone Corporation (NTT), Japan. From 1992 to 2008, he was with NTT Docomo, Inc., Japan. From 1998 to 1999, he was at the Deutsche Telekom Technologiezentrum Darmstadt, Germany, as a visiting researcher. Since 2009, he has been with Softbank Mobile Corporation as a Deputy General Manager in Wireless System Research Centre. He has been engaged in the areas of mobile radio communication systems and cognitive radio systems.

Dr. Yoshino received the Excellent Paper Award from the Institute of Electronics, Information, and Communication Engineers (IEICE) of Japan in 1995. He also received the Best Paper Award from CrownCom 2008, ITU-AJ achievement award from the ITU Association of Japan, both in 2008.
He currently serves as chairman of WG5 (New Technology and Systems) of ITU-R WP5A and is working on the development of ITU-R Report on Cognitive Radio Systems in the land mobile service. He is a member of IEEE, IEICE of Japan.

Biography

Dr. Hiroshi Harada is the director of the Ubiquitous Mobile Communication Group at National Institute of Information and Communications Technology (NICT) and is also the director at NICT’s Singapore Wireless Communication Laboratory. He joined the Communications Research Laboratory, Ministry of Posts and Communications, in 1995 (currently NICT).

Since 1995, he has　researched Software Defined Radio (SDR), Cognitive Radio, Dynamic Spectrum Access Network, and broadband wireless access systems on the microwave and millimeter-wave band. He also has joined many standardization committees and forums in United States as well as in Japan and have fulfilled important roles for them, especially IEEE 802.15.3c, IEEE 1900.4, IEEE1900.6. He has served currently on the board of directors of SDR Forum and the chair of IEEE SCC41(IEEE P1900) since 2009 and the vice chair of IEEE P1900.4 since 2008. He moreover was the chair of the IEICE Technical Committee on Software Radio (TCSR) in 2005-2007 and vice chair of IEEE SCC41 in 2008.

He is also involved in many other activities related to telecommunications. He is a visiting professor of the University of Electro-Communications, Tokyo, Japan, and is the author of Simulation and Software Radio for Mobile Communications (Artech House, 2002).