Cognitive Wireless Networks Cognitive Wireless Networks Concepts, Methodologies and Visions Inspiring the Age of Enlightenment of Wireless Communications

Edited by

Frank H.P. Fitzek Aalborg University, Denmark and

Marcos D. Katz VTT, Finland A C.I.P. Catalogue record for this book is available from the Library of Congress.

ISBN 978-1-4020-5978-0 (HB) ISBN 978-1-4020-5979-7 (e-book)

Published by Springer, P.O. Box 17, 3300 AA Dordrecht, The Netherlands. www.springer.com

Printed on acid-free paper

© 2007 Springer No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission from the Publisher, with the exception of any material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. To our parents

Eta-Marie and Werner

Fanny and Abraham (in memoriam) for their eternal support and loving. What is Cognitive Radio and Cognitive Networks?

Bernhard Walke

RWTH Aachen University, Aachen, Germany

Cognitive Networks based on cognitive radio are addressing a revolutionary technology aiming, besides others, at remarkably improving efficiency of spectrum usage. When introduced, it will fundamentally change the way radio spectrum is regulated and used. Before this may happen, new enabling properties of radios are required such as sensing spectrum occupancy covering a wide range of spectrum and flexible spectrum access adapting to variable channel widths based on reasoning. Cognition has much to do with coexistence management: Coexistence of radio based systems operating in the same or in partly overlapping channels using the same or even different air- interfaces is the challenge to be solved. This appears to be especially difficult to achieve when coexistent radios operate different air interfaces and apply different transmit power levels, since the near-far and hidden terminal problems will apply then and would make coexistence management using de-central control hardly possible. The well-known pilot channel based control applied by an incumbent to control access to its licensed spectrum by third parties to manage coexistence of both appears workable only, if coexistence control is reduced to “yes or no” access permission for non-incumbents, depending on the needs of the primary user what is in fact a TDMA based resource sharing on a long time scale and not coexistence management. Much more sophis- ticated cooperation strategies appear necessary to enable small time-scale, location-specific coexistence management of radio systems, e.g. based on explicit information exchange between the radios involved or just being based on observations made, recently, by a radio following game theoretic reasoning, possibly, combined with well designed back-off algorithms. Prioritization of an incumbent might be part of the rules applied. As is visible from the assembly of contributions to this book, the state-of-the-art towards this is not much progressed, although a rich set of ideas exist potentially contributing to make efficient coexistence control of radios happen. It need not be mentioned that dynamic spectrum assignment can be achieved only if mobile terminals are able to re-configure on all layers of its protocol stacks. Cognitive radio aims to promote technologies as well as changes in radio regulation to overcome some VIII Bernhard Walke existing barriers aiming to improve efficiency of spectrum utilization without scarifying highly reliable communication meeting high quality of service targets. Cognitive networks as a generic approach to exploit cognition in wireless networks: using cognitive principles to improve utilization of resources. In addition to spectral efficiency, for instance energy (power) efficiency can be also enhanced by exploiting cognition. Cognitive radio is just a particular instance of cognitive networks. However, Cognitive Networks / Cognitive Radio is a buzzword, too, since it umbrellas a number of more specific terms used to describe existent radio technology, namely

• Mobile radio, a context-aware radio able to identify (based on cognitive capabilities like reasoning on measurement results) the best suited base station, supporting a given air interface standard, to serve a running session (called handover) or to associate to the base offering the strongest signal. • Multi-band adaptive radio to switch between distant channel groups, without changing the air-interface standard, like in use for GSM 900/1800/1900 MHz bands. Clearly, cognitive capabilities are required to decide on the band to use, based on measurement results. The related technique is dynamic spectrum assignment. • Multi-standard radios able to associate to one out of a number of different air interface standards like GSM/UMTS/CDMA2000/WLAN/others, or even switch air interface across standards during a running session (inter- standards handover). Nobody would call this cognitive radio operation, although a lot of cognition related functions is required to operate a radio like this. • Multi-homing radios able to support different standards air interfaces at the same time. • Reconfigurable radio, e.g., – Hardware Defined Radio (HDR) comprising a set of radios housed in one box, each radio designed to serve a given air-interface, able to decide (based on cognitive capabilities), which radio to operate at a time. – Software Defined Radio (SDR) able to adapt transmission related or even protocol related parameters so that some (or many) properties of the radio are adapted to the needs. SDR would clearly need cognitive capabilities, too, to make senseful decisions. Wireless systems operated in license-exempt (ISM) bands, coexisting and sharing the spectrum according to a standard-specific set of common rules deciding on medium access, reflecting to own observations and based on measurement results, combined with reasoning (using cognitive capabilities). Spectrum etiquette and policies and open spectrum are the terms related to that operation. What is Cognitive Radio and Cognitive Networks? IX

Taking all of these already existent technologies into account, cognitive radios apparently need to go beyond in its aims and ambitions that currently are not well specified and expressed. There is a clear need for sorting things and differentiating known technologies from new ideas. Application of game theoretic models, vertical and hori- zontal spectrum sharing, overlay sharing (like UWB), reasoning and machine- understandable regulatory rules - in general, feature detectors and cyclostationary detectors, spectrum opportunity identification and self-organization and cooperation in wireless networks are examples for new dimensions to be considered in the cognitive radios domain. Besides addressing cognitive networks, the book has a focus on user cooperation: The book advocates the concepts of wireless grids, which is an ad hoc cooperative cluster made of wireless terminals connected over short-range links, but at the same time, being connected to the cellular network. As behind each terminal there is a user who ultimately may decide to join or not a wireless grid, user decisions (individual and group) will have an impact on network operation and performance. Wireless networks enabling social networking and social networks shaping wireless networks are also discussed in the book. Cognitive networks and user cooperation are clearly related and the contributions presented by experts in the respective fields are really worth reading. I have found the themes of the articles invited to form the book very interesting and representing most recent research subjects. May this prove useful to you too.

Aachen, Germany, Bernhard Walke May 2007 Preface

Sapere aude!

Dare to know! Habe Mut, dich deines eigenen Verstandes zu bedienen!

Sapere aude!, the emblematic motto associated with the Age of Enlight- enment, is perhaps a rather eccentric expression to open a book on wireless communications. Alluding to that maxim, the German philosopher Immanuel Kant encouraged people to use their own minds as the basis for reasoning instead of following dogmatic rules. However, the expression has rich con- notations, and we particularly see how dazzlingly inspires the current developments and future of wireless communication networks. This book basically deals with two complementary principles, cognition and cooperation, and how they are becoming essential for future wireless networks. Implicit cognition and cooperation have always been present in any wireless network as fundamental principles for ensuring basic network operation, as for instance the use of common protocols or signaling across the network, estimation of instan- taneous channel conditions, etc. This book focuses on techniques exploiting cooperative and cognitive principles in an explicit manner, that is, purposely implemented by design, and aiming at enhancing the most relevant link and network performance figures as well as improving the efficiency in the use of resources. In general many of these techniques have just recently emerged and currently they are receiving increasing attention by the research community and industry. Cooperation in wireless networks is a well established and rather mature field, whereas cognitive principles, in their explicit way, are rapidly finding their way to the wireless world. The book presents a comprehensive cross-section of these promising fields, exploring these techniques in a highly XII Preface motivating fashion. The goal is to describe key underlying concepts as well as their potentials and challenges. At the same time the book aims at providing mind sparkling discussions which will hopefully trigger further developments in this fertile research field. Thus, rather than being a conventional text book describing well established concepts and techniques, the spirit of the present volume is exploratory and highly motivational. The rationale for the recent extraordinary interest in exploiting cooperative techniques in wireless networks is clear, as demonstrated by the high number of new publications showing concrete advantages and potentials of cooperation. The collaborative interaction of different entities of a wireless network does pay off in basically any network, regardless of the involved access technology, architecture and operating scenarios. The cooperating entities include, among others, basic functional blocks, OSI layers, complete functionalities (e.g., access point, wireless devices), different networks. The benefits of cooperation are manifold, to name a few, increasing data throughput, extending the coverage area, enhancing quality of service and achieving higher efficiency in exploiting radio resources. An important remark is the fact that in addition to the aforementioned (purely technical) cooperating entities, the user, his or her eventual decision on joining a cooperative network and the preferred manner to cooperate are integral parts of the overall cooperative process. User decisions (individual and group) will have an impact on network operation and performance and therefore the social aspects of networking are of great importance. Wireless networks are increasingly enabling social networking, while social networks in turn are shaping the way in which wireless networks operate. Inter and intra network cooperation, presented here as the concept of cellular-controlled peer-to-peer communications will be particularly discussed and presented as a very promising composite access architecture for future wireless networks. Many important aspects of cooperation, together with novel emerging trends will be discussed in many of the upcoming chapters aiming at understanding the potentials and challenges behind the most relevant cooperative concepts suitable for wireless networks. Cooperation brings countless and unique opportunities to tackle many of the problems identified for future high performance wireless networks. From a wider perspective, the research challenges are not just technical but indeed multidisciplinary, involving for instance understanding individual and social behavioral patterns and their impact on the architecture, operation and ultimately performance of a wireless network. As users will become an important part of the cooperative equation, new aspects related to the social interaction between people will come into the scene, like incentives to foster user cooperation, users’ e-reputation and e-trust, security and privacy issues and others. For researchers and developing engineers the crossover between pure wireless communication techniques, group networking and social sciences is truly fascinating. Sapere aude! Preface XIII

Wireless communication networks have always had embedded some basic senses, like sensing the presence or activity of other users, monitoring the state of the channel, etc. In general sensing is followed by some action react- ing in some way to the observation, like channel adaptation, signaling some information to the detected device, etc. The overall action can be understood as a simple cognitive process. In recent years many research initiatives have been focused on exploiting cognitive principles in an even more active fashion, by purposely deploying advanced sensory systems and intelligent processing able to interpret the observed wireless environment and adapt the system ac- cordingly. The immense recent interest on cognitive radio can be considered the starting point triggering the research towards highly developed cognitive wireless networks. We certainly believe that senses of the wireless networks will further develop in accuracy and sensitivity, scrutinizing more and more parameters and activities of the surrounding wireless ecosystem. This will also trigger research targeting techniques for efficiently processing the increasing amount of data resulting from sensing. Moreover, and following the cognitive cycle, understanding the complex and dynamic surrounding scenario based on the on the acquired observations will require analysis tools making use of advanced reasoning techniques, creating a sound background for the following adaptation process. From the reigning spectrum oriented cognitive approach, we expect that additional figures will also monitored in future wireless networks, including other shared resources, configuration, capabilities and status of other surrounding (cooperating or competing) wireless devices, types of application being currently used, and others. A broad and deep understanding of the prevailing immediate wireless scene is paramount to attain high efficiency in the use of radio resources. Energy efficiency, vital for portable wireless devices, is in particular an important target for enhancing through cognition. Heterogeneous wireless networks with heterogeneous network entities, two key attributes of future wireless communication systems, need certainly to resort to cognitive principles in order to use efficiently their resources and ultimately, to support the use of cooperative principles within and across networks. A joint understanding of cognition and cooperation, two highly complementary principles, will render great benefits in terms of resource utilization and communication performance. Bringing cognition and cooperation into wireless networks in a harmonious and engineering attractive manner is a truly challenge for researchers and engineers. However, blending and em- bedding these principles into future wireless networks will be result in some of the most powerful techniques to cope with the clearly identified emerging problems. Eventually, we will witness the rising of wireless networks with such highly developed sensory, processing and reasoning capabilities, paving the way towards conscious wireless networks. Sapere aude! XIV Preface

Figure 1. Overview of the organization and chapters of the book. Preface XV Structure of the Book

This book consists of a collection of 35 chapters written by researchers from academia and research institutes from all over the globe. The chapters explore several technical and social aspects of cooperation and cognition in wireless networks, discussing also emerging trends and concepts in this field. Although this is a stand-alone volume, this book was conceived to complement our previous publication1, in the same fashion that cooperation and cognition in wireless networks complement each other. Parts and corresponding chapters of the book are shown in Figure 1. Part I serves as an introductory and motivating overture of the book, presenting an overview of this emerging field, discussing promising trends and their challenges. Part II deals mainly with cooperative concepts applied to wireless networks, highlighting not only the communicational aspects but also the social and operational ones. In particular the social side of cooperative networking, where users, their interactions and decisions are also taken into account when designing a wireless network, is discussed in detail. Part III introduces cognitive networks, from a generic standpoint, and also considering the currently most studied aspect of them, namely cognitive radio. Part IV explores techniques exploiting both cognitive and cooperative principles, putting into evidence the natural synergy between these approaches. Part V discusses some methodologies and tools used to model, analyze and design cooperative and cognitive networks. Finally, some interesting visions, prospects and emerging technologies are presented in Part VI. We note that the book was deliberately planned to contain assorted chapters of different nature, including motivating discussions, overviews of technical existing technologies, ideas for new concepts, newly proposed and emerging techniques, performance analyses, description and applications of tools for modeling and analyzing cooperative and cognitive techniques as well as visions and prospects. With such a varied source of information we expect that reader will get not only a balanced view of the subject but also, and most importantly, an enlightening introduction to this enthralling field.

Intended Readership

This book is intended to serve as a reference and stimulating source for scien- tists and research engineers developing ideas and concrete concepts for future wireless networks. Furthermore, the academic community engaged in research on advanced wireless networks will ﬁnd in this book a useful source of ideas for further development. Students and self-study readers will be able to get a deep understanding to the latest ideas and future developments in mobile and wireless communications and motivating. 1 “Cooperation in Wireless Networks: Principles and Applications”, edited by Frank H.P. Fitzek and Marcos D. Katz, ISBN1-4020-4710-X. Springer, 2006, pp. 694 XVI Preface Contacting the Editors

The editors welcome any suggestions, comments or constructive criticism on this book. Such a feedback would be used to improve forthcoming editions. Editors can be contacted at [email protected].

Aalborg, Denmark Frank H.P. Fitzek Oulu, Finland Marcos Katz June 2007 Contents

What is Cognitive Radio and Cognitive Networks? Bernhard Walke ...... VII

Part I Introductory Chapter

1 Cooperative and Cognitive Networks: A Motivating Introduction Marcos D. Katz, Frank H.P. Fitzek ...... 3 1.1 Introduction ...... 3 1.2 Ten Tenets Shaping Future Wireless Communications ...... 4 1.3 An Introduction to Cooperative Wireless Networks ...... 14 1.4 An Introduction to Cognitive Communication Systems ...... 20 1.5 Towards Cooperative and Cognitive Wireless Communications . . . 24 1.6 Discussions and Conclusion ...... 25 References ...... 29 2 Cellular Controlled Peer to Peer Communications: Overview and Potentials Frank H.P. Fitzek, Marcos Katz ...... 31 2.1 Challenges for Future Wireless Networks ...... 31 2.2 Premises for Cooperation ...... 36 2.3 Combining the Cellular and the P2P World ...... 39 2.3.1 Cooperative Architecture ...... 40 2.3.2 Realization of the Cellular and the Short Range Link . . . . 41 2.3.3 The Importance of the Short-Range Communication Link 42 2.3.4 Somebody out There? ...... 44 2.3.5 Nature Inspired Cooperation ...... 44 2.4 Cooperative Services ...... 46 2.4.1 Multicast and Broadcast Services ...... 47 2.4.2 Unicast Services ...... 53 XVIII Contents

2.5 Service Discovery within Cooperative Cluster ...... 54 2.6 Beneﬁts of Cooperation in the Wireless World ...... 56 2.7 Conclusion ...... 58 References ...... 58

Part II Cooperative Networks: Social, Operational and Communicational Aspects

3 Applying Evolutionary Approaches for Cooperation David Hales ...... 63 3.1 Introduction ...... 63 3.2 From Evolution to Protocols ...... 64 3.3 Cooperation ...... 66 3.4 The Prisoner’s Dilemma and Variants ...... 67 3.5 Tag-Based Cooperation Algorithm ...... 68 3.6 The SLAC Protocol ...... 69 3.7 Possible Applications ...... 72 3.8 Discussion and Conclusion ...... 73 References ...... 73 4 The Social Qualities of Pervasive Wireless Networks Mark Pesce ...... 75 4.1 Introduction: The Social Hormone ...... 75 4.2 Hyperintelligence and the End of Elites ...... 76 4.3 Pox Populi and the Collapse of the Mass Mind ...... 79 4.4 Read-Write Culture and the Restructuring of Institutions ...... 82 4.5 Conclusion: Pervasive Wireless Networks and the Rise of Hyperpeople ...... 84 References ...... 86 5 Encouraging Cooperative Interaction among Network Entities Sonja Buchegger, John Chuang ...... 87 5.1 Beneﬁts of Network Cooperation ...... 87 5.2 The Cooperation Dilemma...... 88 5.3 Solution Approaches ...... 91 5.3.1 Reputation Systems ...... 91 5.3.2 Payment Systems ...... 93 5.3.3 Barter Systems ...... 94 5.3.4 Enforcement Systems ...... 94 5.4 Challenges ...... 96 5.4.1 Selﬁsh v. Malicious v. Faulty Behavior ...... 96 5.4.2 Observability ...... 96 Contents XIX

5.4.3 Identity ...... 98 5.4.4 Fairness ...... 100 5.4.5 Meta Cooperation ...... 102 5.4.6 Time ...... 103 5.5 Conclusions ...... 105 References ...... 106

6 Competition and Cooperation in Wireless Multi-Access Networks Johan Hultell, Jens Zander, Jan Markendahl ...... 109 6.1 Introduction ...... 109 6.2 Technology for dynamic cooperation and competition ...... 112 6.3 Cooperative Wireless Access ...... 115 6.3.1 Benefits and Perils of Cooperation ...... 115 6.3.2 How Much Can Be Gained through Cooperation? ...... 116 6.3.3 Current Practice of Infrastructure Cooperation ...... 118 6.4 Competitive Wireless Access ...... 119 6.4.1 Benefits of Competitive Wireless Access ...... 119 6.4.2 Feasibility of a Competitive Wireless Access Market . . . . . 120 6.5 Dynamic Cooperation and Competition ...... 126 6.6 Conclusions ...... 130 References ...... 131 7 A Cooperative ID for 4G Simone Frattasi, Hanane Fathi ...... 133 7.1 Introduction ...... 133 7.2 The Fall of 3G ...... 134 7.3 The Raise of 4G ...... 135 7.3.1 Prophetic Visions ...... 135 7.3.2 A Pragmatic Methodology to Define 4G ...... 135 7.4 Examples of User and Group Scenarios ...... 137 7.4.1 Business on-the-Move ...... 137 7.4.2 Smart Shopping ...... 137 7.4.3 Mobile Tourist Guide ...... 137 7.4.4 Personalization Transfer ...... 137 7.5 Key Features of 4G from the User and Group Perspectives ...... 138 7.5.1 User Friendliness, User and Group Personalization ...... 139 7.5.2 Terminal and Network Heterogeneity ...... 140 7.6 Technical Requirements and Expectations for 4G ...... 142 7.6.1 System ...... 143 7.6.2 Services ...... 145 7.6.3 Devices ...... 146 7.7 Towards a Definition of 4G ...... 147 7.7.1 The Ad-Coop Network Model ...... 147 7.7.2 The Alchemy of Cooperation in 4G Wireless ...... 148 XX Contents

7.8 Enabling Wireless Cooperation ...... 149 7.8.1 Group Formation ...... 149 7.8.2 Cooperation Triggers and Types of Cooperation ...... 150 7.8.3 The User Experience...... 150 7.9 Conclusions ...... 151 References ...... 151

8 Implementing Cooperative Wireless Networks Stefan Valentin, Hermann S. Lichte, Holger Karl, Sébastien Simoens, Guillaume Vivier, Josep Vidal, Adrian Agustin ...... 155 8.1 Introduction ...... 155 8.2 Approaches in User Cooperative Diversity ...... 157 8.2.1 From Relaying to User Cooperation Diversity ...... 158 8.2.2 Current Approaches – A Classification ...... 159 8.3 Designing Cooperative Systems – New Problems and Required Functionality ...... 162 8.3.1 Mobile Cooperation ...... 162 8.3.2 Cooperation-Aware Resource Allocation ...... 165 8.3.3 Medium Access Control ...... 168 8.4 Towards Feasibility – Implementing Cooperative Systems ...... 173 8.5 Conclusion ...... 175 References ...... 176 9 Scalable Cooperation in Multi-Terminal Half-Duplex Relay Networks Peter Rost, Gerhard Fettweis ...... 179 9.1 Introduction ...... 179 9.2 Nomenclature and Relay Network Model ...... 181 9.3 Protocols for Half-Duplex Relay Nodes ...... 182 9.3.1 A Compress-And-Forward Based Approach ...... 182 9.3.2 A Decode-And-Forward Based Approach ...... 189 9.3.3 Mixed Strategies ...... 192 9.4 Application to Wireless Communications ...... 193 9.5 Summary ...... 194 References ...... 195 10 Trigger Management and Mobile Node Cooperation Jukka Mäkelä,Kostas Pentikousis, Mikko Majanen, Jyrki Huusko ..... 199 10.1 Introduction ...... 199 10.2 Mobility Triggers ...... 200 10.2.1 TRG Producers and Consumers ...... 200 10.2.2 The Role of TRG ...... 201 10.3 A Trigger Management Architecture ...... 202 10.3.1 Triggering Events Collection ...... 203 10.3.2 Trigger Processing ...... 204 10.3.3 Trigger Repository ...... 204 10.3.4 TRG Policies and Rules ...... 205 Contents XXI

10.4 Routing Group Cooperation ...... 205 10.4.1 Routing Group Formation ...... 206 10.4.2 Stability-Based Multi-Hop Clustering Protocol ...... 207 10.4.3 An Overview of the Gateway Selection Architecture . . . . . 209 10.5 Conclusion ...... 210 References ...... 210

11 Cooperative Mobile Positioning in 4G Wireless Networks Simone Frattasi, Marco Monti ...... 213 11.1 Introduction ...... 213 11.2 Related Work ...... 215 11.2.1 Hybrid Positioning Techniques ...... 216 11.2.2 NLOS Error Mitigation Techniques ...... 217 11.3 The Ad-Coop Positioning System ...... 218 11.3.1 System Architecture ...... 218 11.3.2 Data Fusion Method ...... 219 11.4 Simulation Models ...... 222 11.4.1 Statistical Models for TOA and AOA Estimation Errors . . 223 11.4.2 Statistical Channel Model for RSS Estimation ...... 224 11.5 Simulation Results...... 225 11.5.1 Performance Dependency on the Number of CMs ...... 226 11.5.2 Performance Dependency on the Number of BSs ...... 228 11.6 Localization, Cooperation and Cognition ...... 228 11.7 Conclusions ...... 231 References ...... 232 12 Peer-to-Peer Information Retrieval Based on Fields of Interest Bertalan Forstner, Gergely Csúcs, Imre Kelényi, Hassan Charaf ...... 235 12.1 Inspiration from Everyday Life ...... 235 12.2 Modeling Fields of Interests ...... 239 12.2.1 The Semantic Profile ...... 239 12.2.2 The Connection Profile ...... 240 12.2.3 The Reply Profile ...... 243 12.2.4 The Query Profile ...... 243 12.3 Protocol Extension ...... 244 12.4 Protocol Performance ...... 246 12.5 The Application of Our Results ...... 247 12.5.1 Designing Symella ...... 247 12.5.2 The Architecture of Symella ...... 247 12.6 Conclusion ...... 248 References ...... 248 XXII Contents

Part III Cognitive Networks

13 Introducing Cognitive Systems to the B3G Wireless World P. Demestichas, G. Dimitrakopoulos, K. Tsagkaris, V. Stavroulaki, and A. Katidiotis ...... 253 13.1 Introduction ...... 253 13.1.1 The Wireless World Today ...... 253 13.1.2 Motivation: Cognitive Networks and their Management Functionality ...... 255 13.2 Management Functionality for Cognitive Network Segments ...... 257 13.2.1 Problem Description ...... 257 13.2.2 Cognitive Features ...... 259 13.3 Management Functionality for Cognitive Access Points ...... 260 13.3.1 The Autonomic Management of Access Points (AMAP) . . 260 13.3.2 Cognitive Features ...... 262 13.4 Management Functionality for Cognitive Wireless Terminals . . . . . 262 13.4.1 The Cognitive Reconﬁgurable Equipment Management System (C REMS) ...... 263 13.4.2 Cognitive Features ...... 265 13.5 Conclusions ...... 268 References ...... 269 14 Architectures and Protocols for Next Generation Cognitive Networking B. S. Manoj, Ramesh R. Rao, Michele Zorzi ...... 271 14.1 Introduction ...... 271 14.2 Deﬁnition of Cognitive Networking ...... 272 14.3 Architectures for Cognitive Networking...... 272 14.3.1 Autonomous Cognitive Networking ...... 273 14.3.2 Distributed Cognitive Networking ...... 277 14.4 CogNet: Cognitive Complete Knowledge Network ...... 277 14.4.1 CogPlane and CogBus ...... 279 14.4.2 Case Study: CogTCP ...... 280 14.5 Summary ...... 283 References ...... 284 15 Scheduling in Cognitive Networks Chandrasekharan Raman, Jasvinder Singh, Roy D. Yates, and Narayan B. Mandayam ...... 285 15.1 Introduction ...... 285 15.2 System Model ...... 287 15.3 Maximum Sum Rate Scheduling ...... 290 15.4 Fair Scheduling ...... 291 15.4.1 Max-Min Fairness ...... 292 15.4.2 Proportional Fairness ...... 293 Contents XXIII

15.5 Distributed Dynamic Spectrum Access Policies ...... 293 15.5.1 Rate Regions ...... 294 15.5.2 Characterization of Rate Region for the Decentralized Scheme ...... 295 15.5.3 Distributed Algorithm ...... 297 15.6 Cross Layer Scheduling of End-to-End Flows ...... 299 15.7 Simulation Results...... 301 15.8 Conclusion ...... 302 References ...... 302

16 Design of Terminals and Infrastructure Components for Cognitive Wireless Networks Alexander Vießmann, Admir Burnic, Christoph Spiegel, Arjang Hessamian-Alinejad, Andreas Waadt, Guido H. Bruck, Peter Jung ..... 307 16.1 Ubiquitous Wireless Multimedia ...... 307 16.2 Reconﬁgurability and Cognitive Modes of Operation ...... 309 16.3 Platform Based Design Flow ...... 312 16.4 PROMETHEUS Platform ...... 316 16.4.1 General Concept ...... 316 16.4.2 Transceiver Engines ...... 317 16.4.3 HAWK Transceiver ...... 318 16.5 Future Proofness of the PROMETHEUS Platform ...... 322 16.6 Conclusions ...... 324 References ...... 325 17 Fundamental Limits of Cognitive Radio Networks Natasha Devroye, Vahid Tarokh ...... 327 17.1 Introduction ...... 327 17.1.1 Chapter Outline ...... 329 17.2 Fundamental Limits of Cognitive Radio Channels: Perfect CSI . . . 329 17.2.1 Gaussian Noise ...... 333 17.2.2 Discrete Memoryless Channel ...... 337 17.2.3 Further Results...... 342 17.3 Fundamental Limits of Cognitive Radio Channels: Imperfect CSI and Fading Channels...... 344 17.3.1 The Compound Gel’fand-Pinsker Channel ...... 344 17.3.2 Carbon Copying onto Dirty Paper ...... 346 17.3.3 Gel’fand-Pinkser Coding with Unknown Phase ...... 348 17.4 Conclusion ...... 349 References ...... 349 XXIV Contents

18 Spectrum Awareness: Techniques and Challenges for Active Spectrum Sensing Marko Höyhtyä,Atso Hekkala, Marcos Katz, Aarne Mämmelä ...... 353 18.1 Introduction ...... 353 18.2 A Classification of Spectrum Awareness ...... 354 18.2.1 Passive Awareness ...... 355 18.2.2 Active Awareness ...... 357 18.2.3 Response Time and Topology ...... 358 18.3 Spectrum Sensing Techniques ...... 359 18.3.1 Matched Filter Detection ...... 360 18.3.2 Energy Detection ...... 360 18.3.3 Feature Detection ...... 362 18.3.4 Interference Temperature Concept ...... 363 18.4 Spectrum Sensing Challenges ...... 365 18.5 To Cooperate or Not to Cooperate? ...... 366 18.6 Emerging Techniques ...... 367 18.7 Conclusions ...... 368 References ...... 369 19 Robust Spectrum Sensing Techniques for Cognitive Radio Networks Danijela Cabric, Robert Brodersen ...... 373 19.1 Spectrum Sensing for Cognitive Radio Networks ...... 373 19.1.1 Requirements and Challenges ...... 373 19.1.2 System Design Options ...... 374 19.2 Signal Processing Techniques for Spectrum Sensing ...... 375 19.2.1 Simple General Approach - Energy Detector ...... 375 19.2.2 Exploiting Deterministic Signals - Coherent Processing . . . 377 19.2.3 Detecting Signal Features - Cyclostationary Processing . . . 381 19.3 Network Level Techniques ...... 388 19.3.1 Exploiting Diversity - Cooperative Sensing ...... 388 19.3.2 Limitations in Cooperative Sensing ...... 391 19.4 System Design Guidelines for Spectrum Sensing ...... 392 References ...... 394

Part IV Marrying Cooperation and Cognition in Wireless Networks

20 Cognitive Resource Manager Marina Petrova, Petri M¨ah¨onen ...... 397 20.1 Introduction ...... 397 20.2 CRM Framework ...... 399 20.3 Interfaces ...... 403 20.3.1 ULLA ...... 403 20.3.2 Common Application Requirements Interface ...... 405 20.3.3 Universal Network Interface ...... 405 Contents XXV

20.4 Core Unit Aspects ...... 407 20.4.1 Learning and Reasoning with Genetic Algorithms ...... 407 20.4.2 Decision Making and Utility Functions ...... 410 20.4.3 Managing Time-Scales: CRM-core ...... 415 20.5 Conclusions ...... 418 References ...... 419

21 The C-Cube Concept - Combining Cross-Layer Protocol Design, Cognitive-, and Cooperative Network Concepts Thomas Arildsen, Frank H.P. Fitzek...... 423 21.1 Introduction ...... 423 21.2 Motivation ...... 424 21.3 Cognitive Networking in Cellular Networks ...... 426 21.4 Preliminary Results ...... 429 21.5 Cross-Layer and Cognition Combination ...... 431 21.6 Conclusion ...... 432 References ...... 432 22 Cellular Controlled P2P Communication Using Software Deﬁned Radio Jesper M. Kristensen, Frank H.P. Fitzek ...... 435 22.1 Introduction ...... 435 22.2 Realization Forms of the CCP2P Scenario ...... 436 22.2.1 Multi-Mode Realization ...... 439 22.2.2 Combined Cellular and Short Range Air Interface ...... 439 22.3 SDR and SCR Architectures ...... 447 22.3.1 SCR Architecture Versus SDR Architecture...... 449 22.3.2 SDR Receiver Architecture for Cooperating Terminal . . . . 451 22.4 CCP2P Testbed with the GNU Radio ...... 452 22.4.1 Introduction to GNU Radio ...... 452 22.4.2 GNU Radio Setup for a CCP2P Cooperative Scenario . . . . 453 22.5 Discussion ...... 454 References ...... 454 23 A Cooperative Scheme Enabling Spatial Reuse in Wireless Networks Chenguang Lu, Frank H.P. Fitzek, Patrick C.F. Eggers ...... 457 23.1 Introduction ...... 457 23.2 Description of the Proposed CSR Scheme ...... 458 23.2.1 Cooperation Conditions ...... 460 23.2.2 CSR Capacity Region ...... 461 23.2.3 CSR Availability ...... 462 23.3 CSR with Transmit Beamforming on MISO Links ...... 463 23.3.1 Transmit Beamforming on MISO Links ...... 463 23.3.2 MRC-TDMA Versus ZF-CSR ...... 463 XXVI Contents

23.4 Numerical Examples ...... 466 23.4.1 CSR Availability ...... 466 23.4.2 Capacity Gain ...... 467 23.4.3 Energy Eﬃciency Saving ...... 467 23.5 Conclusions and Outlook ...... 469 References ...... 470

24 On the Energy Saving Potential in DVB-H Networks Exploiting Cooperation among Mobile Devices Qi Zhang, Frank H.P. Fitzek, Marcos Katz ...... 473 24.1 Introduction ...... 473 24.2 Cooperative Strategy for IP-services over DVB-H ...... 475 24.3 Cooperative Short–Range Communication ...... 476 24.3.1 Topology Based Cooperative Algorithm ...... 477 24.3.2 Signalling on the Short-Range Link ...... 478 24.4 Numerical Examples for Energy Consumption Analysis ...... 479 24.5 Conclusion ...... 482 References ...... 484 25 Cooperative Retransmission for Reliable Wireless Multicast Services Qi Zhang, Frank H.P. Fitzek ...... 485 25.1 Introduction ...... 485 25.2 Non–Cooperative Error Recovery Strategies ...... 487 25.2.1 ARQ Scheme ...... 487 25.2.2 FEC/HARQ Schemes ...... 488 25.3 Cooperative Retransmission Strategy ...... 489 25.3.1 Frame Structure Design on Cellular Link with TDD Mode ...... 489 25.3.2 Design Cooperative Retransmission Scheme on the Short–Range Link ...... 490 25.3.3 Energy Consumption by Cooperative Retransmission Protocol ...... 493 25.4 Comparison of Energy Consumption ...... 494 25.5 Conclusion ...... 496 References ...... 497 26 IP Header Compression for Cellular-Controlled P2P Networks Tatiana K. Madsen, Qi Zhang, Frank H.P. Fitzek ...... 499 26.1 Introduction and Motivation ...... 499 26.2 Autonomous and Cooperative Header Compression in Cellular-Controlled P2P Networks ...... 502 26.3 Design of Information Exchange over Short Range Connections . . . 504 26.4 Evaluation of CCP2P Header Compression ...... 506 26.4.1 Probability of Error Burst ...... 506 26.4.2 Bandwidth Savings and Energy Eﬃciency ...... 507 Contents XXVII

26.5 Discussion on Cooperation Strategies ...... 508 26.6 Conclusions ...... 510 References ...... 510 27 Cluster Based Cooperative Uplink Access in Centralized Wireless Networks Qi Zhang, Frank H.P. Fitzek, Villy B. Iversen ...... 513 27.1 Introduction ...... 513 27.2 CSMA/CA Based MAC Strategies ...... 514 27.2.1 RTS/CTS Strategy ...... 514 27.2.2 Packet Aggregation Strategy ...... 518 27.3 The One4all Strategy ...... 522 27.3.1 Throughput & Channel Access Delay Analysis ...... 523 27.3.2 Energy Consumption Analysis ...... 524 27.4 Numerical Results ...... 524 27.5 Conclusions ...... 526 References ...... 528

Part V Methodologies and Tools

28 Cooperation for Cognitive Networks: A Game Theoretic Perspective Cristina Comaniciu ...... 533 28.1 Future Generation of Wireless Networks: Opportunities and Challenges ...... 533 28.2 A Game Theoretic Framework for Cooperation ...... 534 28.2.1 Modeling the Cognition Cycle ...... 534 28.2.2 Coalitional Game Theory...... 535 28.2.3 Non-Cooperative Games ...... 536 28.3 Cooperative Protocols for Cognitive Networks: Some Examples . . . 537 28.3.1 Implicit Cooperation in Protocol Design ...... 537 28.3.2 Incentivizing Cooperation for Non-Cooperative Games . . . 539 28.4 Conclusions and Open Issues ...... 548 References ...... 550 29 Spectrum Sharing Games of Network Operators and Cognitive Radios Mohammad Hossein Manshaei, MárkFélegyházi, Julien Freudiger, Jean-Pierre Hubaux, Peter Marbach ...... 555 29.1 Introduction ...... 555 29.2 Theoretical Background ...... 556 29.2.1 Game Theory ...... 557 29.2.2 Auction Design ...... 559 29.2.3 Graph Coloring ...... 560 XXVIII Contents

29.3 Network Operator Games ...... 561 29.3.1 WAN-WiFi Competition ...... 561 29.3.2 National Border Spectrum Sharing ...... 562 29.3.3 Network Operators Spectrum Sharing ...... 564 29.4 Games in Unlicensed Bands...... 567 29.4.1 Spectrum Sharing among Heterogeneous Wireless Systems 567 29.4.2 Spectrum Sharing among WiFi Operators ...... 569 29.5 Cognitive Radio Games ...... 571 29.5.1 Opportunistic Spectrum Sharing ...... 572 29.5.2 Auction Based Spectrum Sharing ...... 573 29.5.3 Spectrum Sharing in OFDM Networks ...... 574 29.6 Conclusion ...... 577 References ...... 577

30 Introduction to NetLogo Federico Albiero, Frank H.P. Fitzek, Marcos Katz ...... 579 30.1 Why NetLogo ...... 579 30.2 Main Features ...... 580 30.3 Getting Started ...... 581 30.4 A Model for Cooperation in Wireless Networks ...... 583 30.4.1 The PD Iterated Example ...... 583 30.4.2 Modeling Cooperation in Wireless Networks ...... 586 30.5 NetLogo Libraries for Cooperation ...... 587 30.5.1 Model Setup ...... 587 30.5.2 Cooperative Games ...... 595 30.5.3 Displaying Data ...... 599 30.6 Conclusion ...... 600 References ...... 601 31 Analysis of Cooperative Power Saving Strategies with NetLogo Federico Albiero, Frank Fitzek, Marcos Katz ...... 603 31.1 Scenario of Investigation ...... 603 31.2 Theoretic Analysis ...... 605 31.3 Strategies Overview...... 607 31.4 Performance Evaluation ...... 610 31.4.1 Power Saving Gain of Cooperation ...... 611 31.4.2 Mixed Scenario ...... 614 31.4.3 Two-Box Model ...... 615 31.5 Conclusion ...... 619 References ...... 620 Contents XXIX

Part VI Visions, Prospects and Emerging Technologies

32 Cooperation in Optical Wireless Communications Dominic O’Brien ...... 623 32.1 Introduction ...... 623 32.2 Overview of Optical Wireless Communications ...... 624 32.3 System Components ...... 625 32.3.1 Transmitter ...... 626 32.3.2 Receiver ...... 626 32.4 Cooperation between RF and Optical Wireless (OW) Systems . . . 627 32.5 Potential Scenarios for Cooperative Working ...... 628 32.5.1 Hotspots ...... 628 32.5.2 Cooperative Transceivers ...... 628 32.5.3 Enabling Developments ...... 629 32.6 Conclusions ...... 630 References ...... 631 33 Evolution of Digital Radios Friedrich K. Jondral, Volker Blaschke ...... 635 33.1 Introduction ...... 635 33.2 Transmission Physics and Standards ...... 635 33.3 Radio ...... 637 33.4 Digital Radio (DR) ...... 640 33.5 Software Deﬁned Radio (SDR) ...... 643 33.5.1 SDR Processing ...... 643 33.5.2 Parameterization ...... 644 33.5.3 Military SDR - The Software Communications Architecture (SCA) ...... 645 33.6 Cognitive Radio ...... 647 33.6.1 Cognitive Radio Structure ...... 648 33.6.2 Functional Enhancement of Cognitive Radios ...... 649 33.6.3 Cognitive Radio Features in Current and Future Communication Systems ...... 650 33.7 Conclusion ...... 652 References ...... 653 34 CogMesh: A Cluster Based Cognitive Radio Mesh Network Tao Chen, Honggang Zhang, Xiaofei Zhou, Gian Mario Maggio, Imrich Chlamtac ...... 657 34.1 Introduction ...... 657 34.2 Network Model ...... 659 34.3 Network Architecture ...... 661 34.4 MAC Protocol ...... 662 XXX Contents

34.5 Spectrum Hole Detection ...... 663 34.6 Neighbor Discovery and Cluster Formation ...... 664 34.6.1 Analysis of Neighbor Discovery Approaches ...... 666 34.7 Inter-Cluster Connection ...... 666 34.8 Topology Management ...... 668 34.8.1 Nodes Join Network ...... 668 34.8.2 Nodes Leave Network ...... 669 34.8.3 Spectrum Holes Change ...... 670 34.8.4 Cluster Shift Master Channel ...... 670 34.8.5 Merge Clusters ...... 671 34.9 Correctness of Network Connectivity ...... 673 34.10 Simulation Results...... 675 34.11 Conclusion ...... 677 References ...... 677

35 Coordinating User and Device Behavior in Wireless Grids Lee W. McKnight, William Lehr, James Howison ...... 679 35.1 Introduction ...... 679 35.2 From Systems Management to Grid Coordination ...... 680 35.3 Coordinating Strategic Behavior in Distributed Networks ...... 683 35.3.1 Technical ...... 683 35.3.2 Social ...... 685 35.3.3 Legal ...... 687 35.3.4 Economic ...... 688 35.4 Interactions and Dynamics in Regulation ...... 691 35.4.1 Hardening Technical Regulation with Legal Enforcement . 691 35.4.2 New Legal Provisions and Their Surveillance Implications 692 35.5 Conclusion and Implications for Wireless Grids ...... 693 References ...... 694

Index ...... 709 List of Contributors

Marcos Katz D-10587 Berlin VTT Technical Research Centre Germany of Finland [email protected] P.O. Box 1100 FI-90571 Oulu John Chuang Finland School of Information [email protected] University of California at Berkeley 102, South Hall Frank H. P. Fitzek Berkeley, CA 94720 Aalborg University [email protected] Department of Electronic Systems Niels Jernes Vej 12 Johan Hultell 9220 Aalborg Department of Communication [email protected] Systems, Royal Institute of Technology David Hales Isafjordsgatan 30B, Electrum 418 University of Bologna SE-164 40 Kista Dept. of Computer Science [email protected] Mura Anteo Zamboni 7 40127 Bologna, Italy. Jens Zander [email protected] Department of Communication Systems, Royal Institute Mark Pesce of Technology Honorary Associate Isafjordsgatan 30B, Electrum 418 Digital Cultures Program SE-164 40 Kista University of Sydney [email protected] [email protected] Jan Markendahl Sonja Buchegger Department of Communication Deutsche Telekom Laboratories Systems, Royal Institute Ernst-Reuter-Platz 7 of Technology XXXII List of Contributors

Isafjordsgatan 30B, Electrum 418 Guillaume Vivier SE-164 40 Kista Motorola Labs [email protected] Parc Les Algorithmes St-Aubin 91193, France Simone Frattasi [email protected] Center for TeleInFrastruktur (CTIF) Dpt. of Electronic Systems Josep Vidal Antennas, Propagation and Radio Technical University of Catalonia Networking (APNet) Group C/Jordi Girona 1-3 Aalborg University 08034 Barcelona, Spain Niels Jernes Vej 12, 9220 [email protected] Aalborg, Denmark [email protected] Adrian Agustin Hanane Fathi Technical University of Catalonia Research Center for Information C/Jordi Girona 1-3 Security (RCIS) 08034 Barcelona, Spain National Institute of Advanced [email protected] Industrial Science and Technology (AIST) Peter Rost Akihabara-Daibiru 1-18-13, 101-0021 Technische Universit¨atDresden Tokyo, Japan Dresden, Germany [email protected] [email protected]

Stefan Valentin Gerhard Fettweis University of Paderborn Technische UniversitätDresden Warburger Straße 100 Dresden, Germany 33098 Paderborn, Germany [email protected] [email protected] Jukka Mäkelä Hermann S. Lichte VTT Technical Research Centre University of Paderborn of Finland Warburger Straße 100 Oulu, Finland 33098 Paderborn, Germany [email protected] [email protected]

Holger Karl Mikko Majanen University of Paderborn VTT Technical Research Centre Warburger Straße 100 of Finland 33098 Paderborn, Germany Oulu, Finland [email protected] [email protected]

S´ebastien Simoens Kostas Pentikousis Motorola Labs VTT Technical Research Centre Parc Les Algorithmes of Finland St-Aubin 91193, France Oulu, Finland [email protected] [email protected] List of Contributors XXXIII

Jyrki Huusko G. Dimitrakopoulos VTT Technical Research Centre University of Piraeus of Finland Oulu, Finland Department of Digital Systems [email protected] 80 Karaoli Dimitriou str. Piraeus, 18534, GREECE Marco Monti [email protected] CTIF Italy Dpt. of Electronic Engineering University of Rome Tor Vergata K. Tsagkaris Via del Politecnico 1, 00133 University of Piraeus Rome, Italy Department of Digital Systems [email protected] 80 Karaoli Dimitriou str. Piraeus, 18534, GREECE Bertalan Forstner [email protected] Budapest University of Technology and Economics V.Stavroulaki H-1111 Budapest, Goldmann György University of Piraeus tér3. Hungary Department of Digital Systems [email protected] 80 Karaoli Dimitriou str. Gergely Csúcs Piraeus, 18534, GREECE Budapest University of Technology [email protected] and Economics H-1111 Budapest, Goldmann György A. Katidiotis tér3. Hungary University of Piraeus [email protected] Department of Digital Systems 80 Karaoli Dimitriou str. Imre Kelényi Piraeus, 18534, GREECE Budapest University of Technology Tel: +30 210 414 2758, Fax: +30 210 and Economics 414 2753 H-1111 Budapest, Goldmann György tér3. Hungary [email protected] [email protected] B. S. Manoj Hassan Charaf Department of Electrical and Budapest University of Technology Computer Engineering and Economics University of California San Diego H-1111 Budapest, Goldmann György CA 92093 tér3. Hungary [email protected] [email protected]

P. Demestichas Ramesh R. Rao University of Piraeus Department of Electrical Department of Digital Systems and Computer Engineering 80 Karaoli Dimitriou str. University of California San Diego Piraeus, 18534, GREECE CA 92093 [email protected] [email protected] XXXIV List of Contributors

Michele Zorzi Christoph Spiegel Department of Information Lehrstuhl für Engineering University Kommunikationstechnik of Padova, Italy UniversitätDuisburg-Essen [email protected] Germany Christoph.Spiegel@ Chandrasekharan Raman KommunikationsTechnik.org WINLAB, Rutgers 671 US Route 1 South Arjang Hessamian-Alinejad North Brunswick, NJ 08902 Lehrstuhl für [email protected] Kommunikationstechnik UniversitätDuisburg-Essen Jasvinder Singh Germany WINLAB, Rutgers Arjang.Hessamian@ 671 US Route 1 South KommunikationsTechnik.org North Brunswick, NJ 08902 Andreas Waadt [email protected] Lehrstuhl für Roy D. Yates Kommunikationstechnik WINLAB, Rutgers UniversitätDuisburg-Essen Germany 671 US Route 1 South North Brunswick, NJ 08902 Andreas.Waadt@ KommunikationsTechnik.org [email protected] Guido H. Bruck Narayan B. Mandayam Lehrstuhl für WINLAB, Rutgers Kommunikationstechnik 671 US Route 1 South UniversitätDuisburg-Essen North Brunswick, NJ 08902 Germany [email protected] Guido.Bruck@ KommunikationsTechnik.org Alexander Vießmann Lehrstuhl für Peter Jung Kommunikationstechnik Lehrstuhl für UniversitätDuisburg-Essen Kommunikationstechnik Germany UniversitätDuisburg-Essen Alex.Viessmann@ Germany KommunikationsTechnik.org Peter.Jung@ KommunikationsTechnik.org Admir Burnic Lehrstuhl für Natasha Devroye Kommunikationstechnik School of Engineering and Applied UniversitätDuisburg-Essen Sciences Germany Harvard University Admir.Burnic@ Cambridge, MA, U.S.A. KommunikationsTechnik.org [email protected] List of Contributors XXXV

Vahid Tarokh Thomas Arildsen School of Engineering and Applied Aalborg University Sciences Department of Electronic Systems Harvard University Niels Jernes Vej 12 Cambridge, MA, U.S.A. 9220 Aalborg [email protected] [email protected] Marko Höyhtyä VTT Technical Research Centre Chenguang Lu of Finland Aalborg University P.O. Box 1100, FI-90571 Oulu Department of Electronic Systems, Finland APNET Section [email protected] Niels Jernes Vej 12, DK-9220 Aalborg East, Denmark Atso Hekkala VTT Technical Research Centre [email protected] of Finland P.O. Box 1100, FI-90571 Oulu Patrick C.F. Eggers Finland Aalborg University, [email protected] Department of Electronic Systems, APNET Section Aarne Mämmelä Niels Jernes Vej 12, DK-9220 VTT Technical Research Centre Aalborg East, Denmark of Finland [email protected] P.O. Box 1100, FI-90571 Oulu Finland [email protected] Qi Zhang Technical University of Denmark Danijela Cabric Department of Communication University of California, Berkeley Optics & Materials [email protected] Building 343, DK-2800 Kgs. Lyngby Robert Brodersen Denmark University of California, Berkeley [email protected] [email protected] Marina Petrova Tatiana K. Madsen RWTH Aachen University Aalborg University Department of Wireless Networks Niels Jernes Vej 12, Kackertstrasse 9, 52072 Aachen DK-9220 Aalborg, Denmark Germany [email protected] [email protected] Petri Mähönen Jesper M. Kristensen RWTH Aachen University Aalborg University, Department of Wireless Networks Department of Electronic Systems Kackertstrasse 9, 52072 Aachen Niels Jernes Vej 12 Germany DK-9220 Aalborg, Denmark [email protected] [email protected] XXXVI List of Contributors

Villy B. Iversen Volker Blaschke Technical University of Denmark Institut für Nachrichtentechnik Department of Communication UniversitätKarlsruhe (TH) Optics & Materials 76128 Karlsruhe, Germany Building 343, DK-2800 Kgs. Lyngby [email protected] Denmark [email protected] Tao Chen CREATE-NET Cristina Comaniciu Via Solteri 38, TN, Italy Stevens Institute of Technology Hoboken, NJ, USA [email protected] [email protected] Honggang Zhang Mohammad Hossein Manshaei CREATE-NET EPFL, Switzerland Via Solteri 38, TN, Italy [email protected] [email protected] Márk Félegyházi EPFL, Switzerland Xiaofei Zhou [email protected] CREATE-NET Via Solteri 38, TN, Italy Julien Freudiger [email protected] EPFL, Switzerland [email protected] Gian Mario Maggio Jean-Pierre Hubaux CREATE-NET EPFL, Switzerland Via Solteri 38, TN, Italy [email protected] gian-mario.maggio@create-net. Peter Marbach org University of Toronto Imrich Chlamtac Canada CREATE-NET [email protected] Via Solteri 38, TN, Italy Federico Albiero [email protected] VTT - Technical Research Centre of Finland Lee W. McKnight Kaitoväylä1, P.O. Box 1100, School of Information Studies 90571-FI Oulu, Finland Syracuse University [email protected] [email protected] Dominic O’Brien Department of Engineering Science William Lehr University of Oxford Massachusetts Institute Parks Road, Oxford, OX1 3PJ of Technology United Kingdom [email protected] [email protected] James Howison Friedrich K. Jondral School of Information Studies Institut für Nachrichtentechnik Syracuse University UniversitätKarlsruhe (TH) [email protected] 76128 Karlsruhe, Germany [email protected]