FOUNDATION OF COGNITIVE RADIO SYSTEMS Edited by Samuel Cheng Foundation of Cognitive Radio Systems Edited by Samuel Cheng Published by InTech Janeza Trdine 9, 51000 Rijeka, Croatia Copyright © 2012 InTech All chapters are Open Access distributed under the Creative Commons Attribution 3.0 license, which allows users to download, copy and build upon published articles even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. After this work has been published by InTech, authors have the right to republish it, in whole or part, in any publication of which they are the author, and to make other personal use of the work. Any republication, referencing or personal use of the work must explicitly identify the original source. As for readers, this license allows users to download, copy and build upon published chapters even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. Notice Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those of the editors or publisher. No responsibility is accepted for the accuracy of information contained in the published chapters. The publisher assumes no responsibility for any damage or injury to persons or property arising out of the use of any materials, instructions, methods or ideas contained in the book. Publishing Process Manager Bojan Rafaj Technical Editor Teodora Smiljanic Cover Designer InTech Design Team First published March, 2012 Printed in Croatia A free online edition of this book is available at www.intechopen.com Additional hard copies can be obtained from orders@intechweb.org Foundation of Cognitive Radio Systems, Edited by Samuel Cheng p. cm. 978-953-51-0268-7 Contents Preface IX Part 1 Spectrum Sensing Foundation 1 Chapter 1 Exact and Asymptotic Analysis of Largest Eigenvalue Based Spectrum Sensing 3 Olav Tirkkonen and Lu Wei Chapter 2 A Practical Demonstration of Spectrum Sensing for WiMAX Based on Cyclostationary Features 23 Gianmarco Baldini, Raimondo Giuliani, Diego Capriglione and Kandeepan Sithamparanathan Chapter 3 Modulation Classification in Cognitive Radio 43 Adalbery R. Castro, Lilian C. Freitas, Claudomir C. Cardoso, João C.W.A. Costa and Aldebaro B.R. Klautau Chapter 4 Link Quality Prediction in Mobile Ad-Hoc Networks 61 Gregor Gaertner and Eamnn O'Nuallain Part 2 Cooperative Sensing 95 Chapter 5 Collaborative Spectrum Sensing for Cognitive Radio Networks 97 Aminmohammad Roozgard, Yahia Tachwali, Nafise Barzigar and Samuel Cheng Chapter 6 Improving Spectrum Sensing Performance by Exploiting Multiuser Diversity 119 Tuan Do and Brian L. Mark Part 3 Interference Management 141 Chapter 7 Partial Response Signaling: A Powerful Tool for Spectral Shaping in Cognitive Radio Systems 143 Mohammad Mahdi Naghsh and Mohammad Javad Omidi VI Contents Chapter 8 Reconfigurable Multirate Systems in Cognitive Radios 167 Amir Eghbali and Håkan Johansson Chapter 9 Opportunistic Spectrum Access in Cognitive Radio Network 189 Waqas Ahmed, Mike Faulkner and Jason Gao Part 4 Resource Allocation and Beyond 215 Chapter 10 Primary Outage-Based Resource Allocation Strategies 217 Bassem Zayen and Aawatif Hayar Chapter 11 Power Control for Cognitive Radios: A Mixed-Strategy Game-Theoretic Framework 245 Chungang Yang and Jiandong Li Chapter 12 Joint Spectrum Sensing and Resource Scheduling for Cognitive Radio Networks Via Duality Optimization 263 Guoru Ding, Qihui Wu, Jinlong Wang, Fei Song and Yuping Gong Chapter 13 A Roadmap to International Standards Development for Cognitive Radio Systems and Dynamic Spectrum Access 275 Jim Hoffmeyer Preface The wide proliferation of wireless communications unavoidably leads to the scarcity of frequency spectra. On one hand, wireless users become increasingly difficult to find available frequency bands for communications. On the other hand, many preallocated frequency bands are ironically under-utilized and thus the resources there are simply wasted. This situation leads to the introduction of cognitive radio, which was proposed in the last decade to address this dilemma. Under the cognitive radio model, there are mainly two tiers of users. Primary users (PU), who typically require stable frequency spectra for communications, are licensed users and have the rights of priority in using certain frequency spectra. Secondary users (SU), who typically only need to access frequency spectra momentarily, are allowed to use frequency spectra only if they do not interfere with the PU. As a consequence, one can easily see that the ability of sensing an idle spectrum (i.e., spectrum sensing) and the ability to momentarily utilize a spectrum without interfering with PU (i.e., spectrum management) are two essential elements required for the success of cognitive radios. In this book we have comprised 13 chapters from experts of this field to address these two essential elements. We have organized these chapters into four different parts. The first part, spectrum sensing foundation, collects four chapters on fundamental methods on spectrum sensing. The first chapter explains eigenvalue based detectors and also compares that with eigenvalue ratio based detectors. The second chapter provides a practical demonstration of spectrum sensing using cyclostationarity-based detector. It also includes experimental analysis under a realistic WiMAX environment. Chapter 3 explains the use of modulation classification techniques for cognitive radio. Hardware implementations are also described in detail. In Chapter 4, the authors review the most prominent link quality prediction techniques which have been published over the last fifteen years and point out the limitations of existing approaches. In the second part, we move from sensing methods for individual SU to cooperative sensing methods in which multiple SU collaborate to attain better sensing performance. In the first chapter of this part, the author give an overview of cooperative sensing. They also identify research challenges and unsolved issues. In X Preface Chapter 6, the second chapter of this part, the authors look into the possibility of improving spectrum sensing performance by exploiting multiuser diversity. They also describe a practical MAC protocol to coordinate transmissions between SU and a fusion center that handles fusion of sensing information. The remaining two parts deal with the aspects of spectrum management. Part 3 includes chapters that layout the foundation of interference management. Chapter 7, the first chapter of Part 3, introduces partial response signaling as a tool for spectrum shaping in cognitive radio. It addresses the potential weakness of having large out-of- band spectrum components in conventional OFDM based systems. In Chapter 8, the second chapter of Part 3, the authors discuss the structure, reconfiguration, and the parameter selection when adopting the dynamic frequency-band allocation (DFBA) and and dynamic frequency-band reallocation (DFBR) for cognitive radios. They also demonstrate how the reconfigurability can be achieved either by a channel switch or by variable multipliers/commutators. In Chapter 9, the third chapter of Part 3, the authors present detail theoretical analysis of opportunistic spectrum access using continuous-time Markov chains. In particular, they explain how SU may be forced to terminate under different traffic scenarios. The last part of this book includes chapters that focus more on the interaction among multiple SU, which naturally leads to the problem of resource allocation. Chapter 10, the first chapter of Part 4, considers different system models in which SUs compete for a chance to transmit simultaneously or orthogonally with the PU. On the basis of these models, the chapter also offers insights into how to design such scenario in a cognitive radio network environments. Chapter 11, the second chapter of Part 4, focuses on the issue of how to implement interference mitigation by power control techniques amongst multiple cognitive radios in the light of game theory. In Chapter 12, the third chapter of Part 4, the authors design a joint PHY layer cooperative spectrum sensing and MAC layer resource scheduling scheme. They also formulate the joint design as a non-convex optimization problem and derive the asymptotic optimum solution based on recent advances in duality optimization theory. The last chapter of this book is rather different from the rest but is equally important. The author presents a summary of standards activities related to cognitive radio systems and dynamic spectrum access systems. Samuel Cheng, Ph.D. Assistant Professor, School of Electrical and Computer Engineering, University of Oklahoma, Tulsa USA . FOUNDATION OF COGNITIVE RADIO SYSTEMS Edited by Samuel Cheng Foundation of Cognitive Radio Systems Edited by Samuel Cheng Published. investigate the impact of the noise uncertainty on the detection performance. Finally in Section 5 we conclude the main results of this chapter. 4 Foundation of Cognitive Radio Systems Exact and Asymptotic. Spectral Shaping in Cognitive Radio Systems 143 Mohammad Mahdi Naghsh and Mohammad Javad Omidi VI Contents Chapter 8 Reconfigurable Multirate Systems in Cognitive Radios 167 Amir Eghbali