On Fixed-Mobile Network Convergence

As the convergence in digital industry takes shape, the digital networks, both wireline and wireless, are also converging to offer seamless services and enhanced experience to the user. With the arrival of the mobile Internet the mobility is also moving into new areas, e.g., imaging, games, video, multimedia, and across different types of networks. In this paper we explore why, what, and how of the network convergence, and identify how the industry viewpoints align and differ. We also identify the key barriers to achieving true network convergence. We then discuss the role of the Internet Protocol (IP) as the common thread that enables network convergence, and the key industry and standards initiatives to actually provide solutions and the equipment to implement a cost-efficient and high performance converged network. Sudhir Dixit joined Nokia Research Center in 1996, where he is currently a Research Fellow and works on next generation wireless networks. From 1996 to 2003 he was a Senior Research Manager, focusing on IP/ATM, wireless, content networks, and optical networks. Prior to that he worked at NYNEX Science & Technology (now Verizon), GTE (now Verizon), Codex Motorola, Wang, Harris, and STL (now Nortel Europe Labs). He has published or presented over 150 papers, published three books, and holds 14 patents. He is on the Editorial Board of the IEEE Communications Magazine, Springer's Wireless Personal Communications Journal, and KIC's Journal of Communications and Networks. He received a B.E. degree from MANIT, Bhopal, India, an M.E. degree from BITS, Pilani, India, a Ph.D. degree from the University of Strathclyde, Glasgow, Scotland, and an M.B.A. degree from Florida Institute of Technology, Melbourne. He is a Fellow of IEE (UK) and IETE (India). He represents Nokia on the Steering Board of the Wireless World Research Forum, and is also Chair of the SIG on Self-Organization of Wireless World Systems.     

Energy-Aware Interoperability of Manet and 4g Ran Routing

The requirements for telecommunication at 2012 are estimated to be on such demanding level that the 3G technologies will not be sufficient. It is unlikely that the 3G Radio Access Network (RAN) would scale up i.e., Fourth Generation (4G) RAN will need to be developed. The requirements for 4G are demanding and the level of uncertainty is high. The novel ad hoc networking technologies could provide flexible solutions for the 4G RAN and extend the operator radio coverage. Combining these differing communication technologies provides insight for the 4G RAN design. This paper analyses the Mobile Ad hoc Networks (MANET) requirements against the 4G requirements in terms of energy conservation. We find that there is mismatch between these two sets of requirements. Nevertheless, we demonstrate how these two approaches could co-exist in a mutually beneficial way. Finally, we propose interoperability requirements for MANET and 4G routing from the perspective of energy conservation. Harri Paloheimo is a researcher in Networking Technologies Laboratory at Nokia Research Center, Helsinki. In addition, he is a post graduate student in Telecommunications Software and Multimedia Laboratory, Department of Computer Science and Engineering, Helsinki University of Technology. He received M.Sc. degree majoring in space technology from Department of Electrical and Communications Engineering, Helsinki University of Technology in 2000. He currently works on next generation wireless networks with special interest in hybrid and relay networking solutions. Sudhir Dixit is currently a Nokia Research Fellow and works on next generation wireless networks. From 1996 to 2003 he was a Senior Research Manager, focusing on IP/ATM, wireless, content networks, and optical networks. Prior to that he worked at NYNEX Science & Technology (now Verizon), GTE (now Verizon), Codex Motorola, Wang, Harris, and STL (now Nortel Europe Labs). He has published or presented over 150 papers, published three books, and holds 14 patents. He is on the Editorial Board of the IEEE Communications Magazine, Springer's Wireless Personal Communications Journal, and KIC's Journal of Communications and Networks. He received a B.E. degree from MANIT, Bhopal, India, an M.E. degree from BITS, Pilani, India, a Ph.D. degree from the University of Strathclyde, Glasgow, Scotland, and an M.B.A. degree from Florida Institute of Technology, Melbourne. He is a Fellow of IEE (UK) and IETE (India). He represents Nokia on the Steering Board of the Wireless World Research Forum, and is also Vice Chair of the SIG on Self-Organization of Wireless World Systems. Dr.Tech. Antti Ylä-Jääski is a Professor of Telecommunications Software, Telecommunications Software and Multimedia Laboratory, Department of Computer Science and Engineering, Helsinki University of Technology. He is also a Research Fellow in Network Technologies Laboratory, Nokia Research Center, Helsinki. Prof Dr.Tech. Antti Ylä-Jääski received his PhD in ETH Zuerich 1993. Antti has worked with Nokia 1994–2004 in several research management positions with focus on future Internet technologies, mobile networks, applications, services, service management and service architectures. He has published about 30 articles and he holds several approved patents. Antti's current research interests include mobile networking, heterogeneous network environments, services, service architectures, service management and security issues.     

Radio Resource Management with Utility and Pricing for Wireless LAN Hot-Spots

We investigate Wireless LAN hot-spots based on the IEEE 802.11b protocol, considering technical and economic issues of the Radio Resource Allocation. Firstly, we discuss how to model the trade-off between perceived QoS and paid price in the users' request, so as to represent the users as choosing the most satisfactory allocation, determined by service requirements and willingness to pay. After the setup of the users' requests, the multiple medium access mechanism is considered and the network performance is evaluated and discussed. Thus, we investigate the provider's task of having a suitable price policy which gives a satisfactory income and efficiently exploit network capacity. This is also dependent on a price setting that is accepted by the users and optimises resource usage. Finally, we study how the multiple access scheme specified in the IEEE 802.11b protocol combines users' requests to a final allocation, and identify possibilities of improvement for the inherent inefficiencies arising from overload. Leonardo Badia was born in Ferrara, Italy, in 1977. He received the MS Degree in Electrical Engineering and the PhD in Information Engineering both from the University of Ferrara, Italy, in 2000 and 2004 respectively. In 2001 he joined the Department of Engineering of the University of Ferrara, where he is a currently a post-doc researcher. During 2002 and 2003 he was on leave at the Royal Institute of Technology of Stockholm, Sweden. His research interests include energy efficient Ad Hoc Networks, transmission protocol modelling, Admission Control and economic modelling of Radio Resource Management for Wireless Networks. Michele Zorzi was born in Venice, Italy, in 1966. He received the Laurea Degree and the Ph.D. in Electrical Engineering from the University of Padova, Italy, in 1990 and 1994, respectively. During the Academic Year 1992/93, he was on leave as a graduate student at the University of California, San Diego (UCSD), where he did research on multiple access in mobile radio networks. In 1993, he joined the faculty of the Dipartimento di Elettronica e Informazione, Politecnico di Milano, Italy. After spending three years with the Center for Wireless Communications at UCSD, in 1998 he joined the School of Engineering of the University di Ferrara, Italy. Since November 2003, he has been on the faculty at the Information Engineering Department of the University of Padova. His present research interests include performance evaluation in mobile communications systems, random access in mobile radio networks, ad hoc and sensor networks, and energy constrained communications protocols. Dr. Zorzi is the Editor-In-Chief of the IEEE Wireless Communications Magazine, and currently serves on the Editorial Boards of the IEEE Transactions on Communications, the IEEE Transactions on Wireless Communications, the IEEE Transactions on Mobile Computing, the Wiley Journal of Wireless Communications and Mobile Computing and the ACM/URSI/ Kluwer Journal of Wireless Networks.     

Dynamic utility and price based radio resource management for rate adaptive traffic

This paper explores analytical Radio Resource Management models where the relationship between users and services is mapped through utility functions. Compared to other applications of these models to networking, we focus in particular on specific aspects of multimedia systems with adaptive traffic, and propose a novel framework for describing and investigating dynamic allocation of resources in wireless networks. In doing so, we also consider economic aspects, such as the financial needs of the provider and the users’ reaction to prices. As an example of how our analytical tool can be used, in this paper we compare different classes of RRM strategies, e.g., Best Effort vs. Guaranteed Performance, for which we explore the relationships between Radio Resource Allocation, pricing, provider’s revenue, network capacity and users’ satisfaction. Finally, we present a discussion about Economic Admission Control, which can be applied in Best Effort scenarios to further improve the performance. Part of this work has been presented at the conference ACM/IEEE MSWiM 2004, Venice (Italy). Leonardo Badia received a Laurea degree (with honors) in electrical engineering and a Ph.D. in information engineering from the University of Ferrara, Italy, in 2000 and 2004, respectively. He was a Research Fellow at the University of Ferrara from 2001 to 2006. During these years, he also had collaborations with the University of Padova, Italy, and Wireless@KTH, Royal Institute of Technology, Stockholm, Sweden. In 2006, he joined the “Institutions Markets Technologies” (IMT) Institute for Advanced Studies, Lucca, Italy, where he is currently a Research Fellow. His research interests include wireless ad hoc and mesh networks, analysis of transmission protocols, optimization tools and economic models applied to radio resource management. Michele Zorzi received a Laurea degree and a Ph.D. in electrical engineering from the University of Padova in 1990 and 1994, respectively. During academic year 1992–1993, he was on leave at UCSD, attending graduate courses and doing research on multiple access in mobile radio networks. In 1993 he joined the faculty of the Dipartimento di Elettronica e Informazione, Politecnico di Milano, Italy. After spending three years with the Center for Wireless Communications at UCSD, in 1998 he joined the School of Engineering of the University of Ferrara, Italy, where he became a professor in 2000. Since November 2003 he has been on the faculty at the Information Engineering Department of the University of Padova. His present research interests include performance evaluation in mobile communications systems, random access in mobile radio networks, ad hoc and sensor networks, energy constrained communications protocols, and broadband wireless access. He was Editor-In-Chief of IEEE Wireless Communications, 2003–2005, and currently serves on the Editorial Boards of IEEE Transactions on Communications, IEEE Transactions on Wireless Communications, Wiley’s Journal of Wireless Communications and Mobile Computing, and ACM/URSI/Kluwer Journal of Wireless Networks, and on the Steering Committee of the IEEE Transactions on Mobile Computing. He has also been a Guest Editor of special issues in IEEE Personal Communications (Energy Management in Personal Communications Systems) and IEEE Journal on Selected Areas in Communications (Multimedia Network Radios).     

A rendezvous reservation protocol for energy constrained wireless infrastructure networks

This paper considers a low power wireless infrastructure network that uses multi-hop communications to provide end user connectivity. A generalized Rendezvous Reservation Protocol (RRP) is proposed which permits multi-hop infrastructure nodes to adapt their power consumption in a dynamic fashion. When nodes have a long-term association, power consumption can be reduced by having them periodically rendezvous for the purpose of exchanging data packets. In order to support certain applications, the system invokes a connection set up process to establish the end-to-end path and selects node rendezvous rates along the intermediate nodes to meet the application’s quality of service (QoS) needs. Thus, the design challenge is to dynamically determine rendezvous intervals based on incoming applications’ QoS needs, while conserving battery power. In this paper, we present the basic RRP mechanism and an enhanced mechanism called Rendezvous Reservation Protocol with Battery Management (RRP-BM) that incorporates node battery level information. The performance of the system is studied using discrete-event simulation based experiments for different network topologies. The chief metrics considered are average power consumption and system lifetime (that is to be maximized). The QoS metrics specified are packet latency and end-to-end setup latency. It is shown that the use of the RRP-BM can increase the lifetime up to 48% as compared to basic RRP by efficiently reducing the energy consumption. This work was supported by a grant from the Natural Sciences and Engineering Research Council of Canada and Communications and Information Technology Ontario (CITO). Part of the research was supported by Air Force Office of Scientific Research grants F-49620-97-1-0471 and F-49620-99-1-0125; Laboratory for Telecommunications Sciences, Adelphi, Maryland; and Intel Corporation. The authors may be reached via e-mail at todd@mcmaster. ca, krishna@umbc. edu. The basic RRP mechanism was presented at the IASTED International Conference on Wireless and Optical Communications, Banff, Canada, July 2002. Subalakshmi Venugopal received her Bachelors in Computer Science from R.V. College of Engineering, Bangalore, India and her M.S. degree in Computer Science from Washington State University. She interned as a student researcher at the Indian Institute of Science, Bangalore, India. Ms. Venugopal is currently employed with Microsoft Corporation in Redmond, WA and is part of the “Kids and Education Group”. Her research interests include low power wireless ad hoc networks. Zhengwei (Wesley) Chen received the M.E. in Electrical & Computer Engineering Dept from McMaster University in Canada in 2002. He joined Motorola Inc. as a CDMA2000 system engineer in 2000. In 2002, he joined UTStarcom as a manager of the Global Service Solution Department. He is currently in charge of R&D for Advanced Services related to the TVoIP and Softswitch products. Terry Todd received the B.A.Sc, M.A.Sc and Ph.D degrees in Electrical Engineering from the University of Waterloo in Waterloo, Ontario, Canada. While at Waterloo he also spent 3 years as a Research Associate with the Computer Communications Networks Group (CCNG). During that time he worked on the Waterloo Experimental Local Area Network, which was an early local area network testbed. In 1991 Dr. Todd was on research leave in the Distributed Systems Research Department at AT&T Bell Laboratories in Murray Hill, NJ. He also spent 1998 as a visiting researcher at The Olivetti and Oracle Research Laboratory (ORL) in Cambridge, England. While at ORL he worked on the piconet project, which was an embedded low power wireless network testbed. Dr. Todd is currently a Professor of Electrical and Computer Engineering at McMaster University in Hamilton, Ontario, Canada. At McMaster he has been the Principal Investigator on a number of major research projects in the optical and wireless networking areas. He currently directs a large group working on wireless mesh networks and wireless VoIP. Professor Todd holds the NSERC/RIM/CITO Chair on Pico-Cellular Wireless Internet Access Networks. Dr. Todd’s research interests include metropolitan/local area networks, wireless communications and the performance analysis of computer communication networks and systems. Professor Todd is a Professional Engineer in the province of Ontario. Krishna M. Sivalingam is an Associate Professor in the Dept. of CSEE at University of Maryland, Baltimore County. Previously, he was with the School of EECS at Washington State University, Pullman from 1997 until 2002; and with the University of North Carolina Greensboro from 1994 until 1997. He has also conducted research at Lucent Technologies’ Bell Labs in Murray Hill, NJ, and at AT&T Labs in Whippany, NJ. He received his Ph.D. and M.S. degrees in Computer Science from State University of New York at Buffalo in 1994 and 1990 respectively; and his B.E. degree in Computer Science and Engineering in 1988 from Anna University, Chennai (Madras), India. While at SUNY Buffalo, he was a Presidential Fellow from 1988 to 1991. His research interests include wireless networks, optical wavelength division multiplexed networks, and performance evaluation. He holds three patents in wireless networks and has published several research articles including more than thirty journal publications. He has published an edited book on Wireless Sensor Networks in 2004 and edited books on optical WDM networks in 2000 and 2004. He served as a Guest Co-Editor for special issues of the ACM MONET journal on “Wireless Sensor Networks” in 2003 and 2004; and an issue of the IEEE Journal on Selected Areas in Communications on optical WDM networks (2000). He is co-recipient of the Best Paper Award at the IEEE International Conference on Networks 2000 held in Singapore. His work has been supported by several sources including AFOSR, NSF, Cisco, Intel and Laboratory for Telecommunication Sciences. He is a member of the Editorial Board for ACM Wireless Networks Journal, IEEE Transactions on Mobile Computing, Ad Hoc and Sensor Wireless Networks Journal, and KICS Journal of Computer Networks. He serves as Steering Committee Co-Chair for IEEE/CreateNet International Conference on Broadband Networks (BroadNets) that was created in 2004. He is currently serving as General Co-Vice-Chair for the Second Annual International Mobiquitous conference to be held in San Diego in 2005 and as General Co-Chair for the First IEEE/CreateNet International Conference on Security and Privacy for Emerging Areas in Communication Networks (SecureComm) to be held in Athens, Greece in Sep. 2005. He served as Technical Program Co-Chair for the First IEEE Conference on Sensor and Ad Hoc Communications and Networks (SECON) held at Santa Clara, CA in 2004; as General Co-Chair for SPIE Opticomm 2003 (Dallas, TX) and for ACM Intl. Workshop on Wireless Sensor Networks and Applications (WSNA) 2003 held in conjunction with ACM MobiCom 2003 at San Diego, CA; as Technical Program Co-Chair of SPIE/IEEE/ACM OptiComm conference at Boston, MA in July 2002; and as Workshop Co-Chair for WSNA 2002 held in conjunction with ACM MobiCom 2002 at Atlanta, GA in Sep 2002. He is a Senior Member of IEEE and a member of ACM.     

Adaptive Coding and Modulation for Mobile Wireless Access Via High Altitude Platforms

In this paper we are concerned with broadband wireless access via high altitude platform system, providing the Internet access and broadband multimedia services to passengers equipped with WLAN terminals connecting through a collective terminal mounted on the train. The main challenge in such scenario is the development of efficient and reliable radio interface for the broadband communication link in the mobile wireless access segment. We are focusing on performance analysis of the adaptive coding and modulation scheme in the communication link between a high altitude platform and a collective terminal on-board moving train. In order to increase the reliability of the communication system in a fading environment we also exploit space and platform diversity. The proposed approach significantly increases the throughput of the wireless access system, while bit error rate remains below the target value regardless of the considered propagation environment.Tomaz Javornik received his B.Sc., M.Sc. and Ph.D. degrees in electrical engineering from the University of Ljubljana, Slovenia, in 1987, 1990 and 1993, respectively. He joined the Jozef Stefan Institute in 1987, where he currently works as a researcher in the Department of Digital Communications and Networks. He is involved in the study of digital radio-relay systems, modulation techniques, coding, adaptive signal processing and digital mobile communication systems.Mihael Mohorcic received B.Sc., M.Sc. and Ph.D. degrees in Electrical Engineering from the University of Ljubljana, Slovenia, in 1994, 1998 and 2002, respectively, and M.Phil. degree in Electrical Engineering from University of Bradford, UK, in 1998. He is a research fellow in the Department of Digital Communications and Networks at the Jozef Stefan Institute. In 1996/1997 he spent 12 months as a Visiting Scientist at University of Bradford, Bradford, UK. His research interests include development and performance evaluation of network protocols and architectures for mobile and wireless communication systems, and resource management in satellite and high altitude platforms networks with the emphasis on routing algorithms and traffic engineering. He is a member of IEEE.Ales Svigelj received his B.Sc., M.Sc. and Ph.D. degrees in Electrical Engineering from the University of Ljubljana, Ljubljana, Slovenia, in 1997, 2000 and 2003 respectively. He is a research associate in the Department of Digital Communications and Networks at the Jozef Stefan Institute. In 2000/2001 he spent one year as a visiting researcher at Leeds Metropolitan University in Leeds, UK. He has participated in several national and international projects. His research interests concern the development of telecommunications systems, network protocols and architectures for satellite, high altitude platforms and terrestrial mobile communication systems. In 2004 he was awarded with The Jozef Stefan Golden Emblem Prize for outstanding contributions made to science in Doctoral theses in the field of natural sciences in Slovenia.Igor Ozimek received his B.Sc., M.Sc. and Ph.D. degrees in electrical engineering from the University of Ljubljana, Slovenia in 1980, 1988 and 1993, respectively. Since 1980 he has been with the Jozef Stefan Institute, Ljubljana, where he works as a researcher. His current interests include digital communications,DSP processing and computer networks.Gorazd Kandus received B.Sc., M.Sc. and Ph.D. degrees in Electrical Engineering from the University of Ljubljana, Ljubljana, Slovenia, in 1971, 1974 and 1991, respectively. He is currently the head of the Department of Digital Communications and Networks at the Jozef Stefan Institute and a Professor at the Faculty of Electrical Engineering, Computer Science and Information Technology, University of Maribor. He spent one year at Worchester Polytechnic Institute, Worchester, MA, as a Fulbright Fellow and 5 months as a Visiting Scientist at the University of Karlsruhe, Germany. His main research interests include design and simulation of mobile and wireless communication systems and development of new telecommunication services. He is a member of IEEE and Upsilon Pi Epsilon.     

Finding Minimum Energy Disjoint Paths in Wireless Ad-Hoc Networks

We develop algorithms for finding minimum energy disjoint paths in an all-wireless network, for both the node and link-disjoint cases. Our major results include a novel polynomial time algorithm that optimally solves the minimum energy 2 link-disjoint paths problem, as well as a polynomial time algorithm for the minimum energy k node-disjoint paths problem. In addition, we present efficient heuristic algorithms for both problems. Our results show that link-disjoint paths consume substantially less energy than node-disjoint paths. We also found that the incremental energy of additional link-disjoint paths is decreasing. This finding is somewhat surprising due to the fact that in general networks additional paths are typically longer than the shortest path. However, in a wireless network, additional paths can be obtained at lower energy due to the broadcast nature of the wireless medium. Finally, we discuss issues regarding distributed implementation and present distributed versions of the optimal centralized algorithms presented in the paper.Anand Srinivas is currently a PhD candidate in the Laboratory for Information and Decision Systems (LIDS) at MIT. He recieved his Masters of Science in EECS from MIT in 2004, and his Bachelors of Applied Science in Computer Engineering from the University of Toronto in 2001. In 2004 he also received a Masters of Science in Aerospace Engineering from MIT. His current research interests include reliability and energy-efficiency in wireless ad-hoc networks, routing and network optimization, graph theory, and the design of efficient algorithms. E-mail: anand3@mit.eduEytan Modiano received his B.S. degree in Electrical Engineering and Computer Science from the University of Connecticut at Storrs in 1986 and his M.S. and Ph.D. degrees, both in Electrical Engineering, from the University of Maryland, College Park, MD, in 1989 and 1992 respectively. He was a Naval Research Laboratory Fellow between 1987 and 1992 and a National Research Council Post Doctoral Fellow during 1992–1993 while he was conducting research on security and performance issues in distributed network protocols.Between 1993 and 1999 he was with the Communications Division at MIT Lincoln Laboratory where he designed communication protocols for satellite, wireless, and optical networks and was the project leader for MIT Lincoln Laboratory’s Next Generation Internet (NGI) project. He joined the MIT faculty in 1999, where he is presently an Associate Professor in the Department of Aeronautics and Astronautics and the Laboratory for Information and Decision Systems (LIDS). His research is on communication networks and protocols with emphasis on satellite, wireless, and optical networks.He is currently an Associate Editor for Communication Networks for IEEE Transactions on Information Theory and for The International Journal of Satellite Communications. He had served as a guest editor for IEEE JSAC special issue on WDM network architectures; the Computer Networks Journal special issue on Broadband Internet Access; the Journal of Communications and Networks special issue on Wireless Ad-Hoc Networks; and for IEEE Journal of Lightwave Technology special issue on Optical Networks. He is the Technical Program co-chair for Wiopt 2006 and vice- chair for Infocom 2007. E-mail: modiano@mit.edu     

Location-aware resource management in mobile ad hoc networks

We propose an innovative resource management scheme for TDMA based mobile ad hoc networks. Since communications between some important nodes in the network are more critical, they should be accepted by the network with high priority in terms of network resource usage and quality of service (QoS) support. In this scheme, we design a location-aware bandwidth pre-reservation mechanism, which takes advantage of each mobile node’s geographic location information to pre-reserve bandwidth for such high priority connections and thus greatly reduces potential scheduling conflicts for transmissions. In addition, an end-to-end bandwidth calculation and reservation algorithm is proposed to make use of the pre-reserved bandwidth. In this way, time slot collisions among different connections and in adjacent wireless links along a connection can be reduced so that more high priority connections can be accepted into the network without seriously hurting admissions of other connections. The salient feature of our scheme is the collaboration between the routing and MAC layer that results in the more efficient spatial reuse of limited resources, which demonstrates how cross-layer design leads to better performance in QoS support. Extensive simulations show that our scheme can successfully provide better communication quality to important nodes at a relatively low price. Finally, several design issues and future work are discussed. Xiang Chen received the B.E. and M.E. degrees in electrical engineering from Shanghai Jiao Tong University, Shanghai, China, in 1997 and 2000, respectively. Afterwards, he worked as a MTS (member of technical staff) in Bell Laboratories, Beijing, China. He is currently working toward the Ph.D. degree in the department of Electrical and Computer Engineering at the University of Florida. His research is focused on protocol design and performance evaluation in wireless networks, including cellular networks, wireless LANs, and mobile ad hoc networks. He is a member of Tau Beta Pi and a student member of IEEE. Wei Liu received the BE and ME degrees in electrical engineering from Huazhong University of Science and Technology, Wuhan, China, in 1998 and 2001, respectively. He is currently pursuing the P.hD. degree in the Department of Electrical and Computer Engineering, University of Florida, Gainesville, where he is a research assistant in the Wireless Networks Laboratory (WINET). His research interest includes QoS, secure and power efficient routing, and MAC protocols in mobile ad hoc networks and sensor networks. He is a student member of the IEEE. Hongqiang Zhai received the B.E. and M.E. degrees in electrical engineering from Tsinghua University, Beijing, China, in July 1999 and January 2002 respectively. He worked as a research intern in Bell Labs Research China from June 2001 to December 2001, and in Microsoft Research Asia from January 2002 to July 2002. Currently he is pursuing the Ph.D. degree in the Department of Electrical and Computer Engineering, University of Florida. He is a student member of IEEE. Yuguang Fang received a Ph.D. degree in Systems and Control Engineering from Case Western Reserve University in January 1994, and a Ph.D. degree in Electrical Engineering from Boston University in May 1997. From June 1997 to July 1998, he was a Visiting Assistant Professor in Department of Electrical Engineering at the University of Texas at Dallas. From July 1998 to May 2000, he was an Assistant Professor in the Department of Electrical and Computer Engineering at New Jersey Institute of Technology. In May 2000, he joined the Department of Electrical and Computer Engineering at University of Florida where he got the early promotion to Associate Professor with tenure in August 2003 and to Full Professor in August 2005. He has published over 180 papers in refereed professional journals and conferences. He received the National Science Foundation Faculty Early Career Award in 2001 and the Office of Naval Research Young Investigator Award in 2002. He is currently serving as an Editor for many journals including IEEE Transactions on Communications, IEEE Transactions on Wireless Communications, IEEETransactions on Mobile Computing, and ACM Wireless Networks. He is also actively participating in conference organization such as the Program Vice-Chair for IEEE INFOCOM’2005, Program Co-Chair for the Global Internet and Next Generation Networks Symposium in IEEE Globecom’2004 and the Program Vice Chair for 2000 IEEE Wireless Communications and Networking Conference (WCNC’2000).     

Virtual Private Ad Hoc Networking

The fact that a lot of applications require secure communication to take place only between a dynamic subset of distributed devices sharing a common context, is, from a network point of view, very challenging and demanding. Existing technologies such as VPN, P2P overlays or VLANs can only partially respond to these requirements. This observation is the key factor that has driven the proposal of the virtual private ad hoc network concept. Virtual private ad hoc networks (VPAN) are secure and self-organizing overlay networks on top of existing IP infrastructure that use ad hoc networking techniques to enable network connectivity. The underlying IP infrastructure can be the Internet, cellular networks, ad hoc networks, mesh networks … or combinations thereof. A virtual private ad hoc overlay network creates a transparent, shielded and trusted environment for the applications and services running on the participants' devices. The overlay uses internal addressing and ad hoc routing, thereby forming a virtual network on top of the physical infrastructure. In addition, the overlay must be self-organizing and self-maintaining upon member mobility or membership changes. This paper gives an overview of the potential applications, a high-level network architecture and the network challenges emerging from the novel concept of virtual private ad hoc networking. Jeroen Hoebeke was born in Ghent, Belgium in 1979. In 2002 he received the Masters degree in engineering (Computer Science) from the University of Ghent. In August 2002, he joined the Broadband Communications Networks Group. His PhD research includes the development of adaptive routing protocol techniques for mobile ad hoc networks. His main research interests are in ad hoc wireless communications and, more generally, in broadband wireless communications. Within the European MAGNET project, he is actively involved in the development of a network architecture and demonstrator for Personal Networks, with a prime focus on routing and connectivity. Gerry Holderbeke was born in Zottegem, Belgium in 1982. He graduated in Informatics at the University of Ghent in 2004. In August 2004 he joined the Broadband Communications Networks Group where he is currently working as a project developer. His research currently includes the development of an emulator for mobile ad hoc networks. His main research interests are in ad hoc networks and broadband wireless communications and involve routing, addressing and more generally, communication within mobile ad hoc networks and infrastructured networks. Within the European MAGNET project, he is actively involved in the development of a network architecture for Personal Networks, with a prime focus on the implementation of the routing architecture. Ingrid Moerman was born in Gent, Belgium in 1965. She received the degree in Electro-technical Engineering and the Ph.D degree from the Ghent University, Gent, Belgium in 1987 and 1992, respectively. Since 1987, she has been with the Interuniversity Micro-Electronics Centre (IMEC) at the Department of Information Technology (INTEC) of the Ghent University, where she conducted research in the field of optoelectronics. In 1997, she became a permanent member of the Research Staff at IMEC. Since 2000 she is part-time professor at the Ghent University. Since 2001 she has switched her research domain to broadband communication networks. She is currently involved in the research and education on broadband mobile & wireless communication networks and on multimedia over IP. The main research topics related to mobile & wireless communication networks are: wireless access to vehicles (high bandwidth & driving speed), adaptive QoS routing in wireless ad hoc networks, body area networks, protocol boosting on wireless links, design of fixed access/metro part, traffic engineering and QoS support in the wireless access network. Ingrid Moerman is author or co-author of more than 300 publications in the field of optoelectronics and communication networks. Bart Dhoedt received a degree in Engineering from the Ghent University in 1990. In September 1990, he joined the Department of Information Technology of the Faculty of Applied Sciences, University of Ghent. His research, addressing the use of micro-optics to realize parallel free space optical interconnects, resulted in a PhD degree in 1995. After a 2 year post-doc in opto-electronics, he became professor at the Faculty of Applied Sciences, Department of Information Technology. Since then, he is responsible for several courses on algorithms, programming and software development. His research interests are software engineering and mobile & wireless communications. Bart Dhoedt is author or co-author of approximately 70 papers published in international journals or in the proceedings of international conferences. His current research addresses software technologies for communication networks, peer-to-peer networks, mobile networks and active networks. Piet Demeester received the Masters degree in Electro-technical engineering and the Ph.D degree from the Ghent University, Gent, Belgium in 1984 and 1988, respectively. In 1992 he started a new research activity on broadband communication networks resulting in the IBCN-group (INTEC Broadband communications network research group). Since 1993 he became professor at the Ghent University where he is responsible for the research and education on communication networks. The research activities cover various communication networks (IP, ATM, SDH, WDM, access, active, mobile), including network planning, network and service management, telecom software, internetworking, network protocols for QoS support, etc. Piet Demeester is author of more than 300 publications in the area of network design, optimization and management. He is member of the editorial board of several international journals and has been member of several technical program committees (ECOC, OFC, DRCN, ICCCN, IZS, &).     

Statistically assisted routing algorithms (SARA) for hop count based forwarding in wireless sensor networks

The main goal of this paper is to provide routing–table-free online algorithms for wireless sensor networks (WSNs) to select cost (e.g., node residual energies) and delay efficient paths. As basic information to drive the routing process, both node costs and hop count distances are considered. Particular emphasis is given to greedy routing schemes, due to their suitability for resource constrained and highly dynamic networks. For what concerns greedy forwarding, we present the Statistically Assisted Routing Algorithm (SARA), where forwarding decisions are driven by statistical information on the costs of the nodes within coverage and in the second order neighborhood. By analysis, we prove that an optimal online policy exists, we derive its form and we exploit it as the core of SARA. Besides greedy techniques, sub–optimal algorithms where node costs can be partially propagated through the network are also presented. These techniques are based on real time learning LRTA algorithms which, through an initial exploratory phase, converge to quasi globally optimal paths. All the proposed schemes are then compared by simulation against globally optimal solutions, discussing the involved trade–offs and possible performance gains. The results show that the exploitation of second order cost information in SARA substantially increases the goodness of the selected paths with respect to fully localized greedy routing. Finally, the path quality can be further increased by LRTA schemes, whose convergence can be considerably enhanced by properly setting real time search parameters. However, these solutions fail in highly dynamic scenarios as they are unable to adapt the search process to time varying costs. Michele Rossi was born in Ferrara, Italy on October 30th, 1974. He received the Laurea degree in Electrical Engineering (with honors) and the Ph.D. degree in Information Engineering from the University of Ferrara in 2000 and 2004, respectively. Since 2000 he has been a Research Fellow at the Department of Engineering of the University of Ferrara. During 2003 he was on leave at the Center for Wireless Communications (CWC) at the University of California San Diego (UCSD), where he did research on wireless sensor networks. In November 2005 he joined the Department of Information Engineering of the University of Padova, Italy, where he is currently an Assistant Professor. Michele Rossi is currently part of the EU funded Ambient Networks and eSENSE projects. His research interests include: TCP/IP protocols over wireless networks, performance analysis of link layer retransmission techniques, routing and access selection in heterogeneous wireless networks and MAC/routing algorithms for wireless sensor networks. Michele Zorzi was born in Venice, Italy, in 1966. He received the Laurea degree and the Ph.D. degree in Electrical Engineering from the University of Padova, Italy, in 1990 and 1994, respectively. During the Academic Year 1992/93, he was on leave at the University of California, San Diego (UCSD), attending graduate courses and doing research on multiple access in mobile radio networks. In 1993, he joined the faculty of the Dipartimento di Elettronica e Informazione, Politecnico di Milano, Italy. After spending three years with the Center for Wireless Communications at UCSD, in 1998 he joined the School of Engineering of the University of Ferrara, Italy, and in 2003 joined the Department of Information Engineering of the University of Padova, Italy, where he is currently a Professor. His present research interests include performance evaluation in mobile communications systems, random access in mobile radio networks, ad hoc and sensor networks, and energy constrained communications protocols. Dr. Zorzi from 2003 to 2005 was the Editor-In-Chief of the IEEE Wireless Communications Magazine, and currently serves on the Editorial Boards of the IEEE Transactions on Communications, the IEEE Transactions on Wireless Communications, the IEEE Transactions on Mobile Computing, the Wiley Journal of Wireless Communications and Mobile Computing and the ACM/URSI/Kluwer Journal of Wireless Networks. He was also guest editor for special issues in the IEEE Personal Communications Magazine (Energy Management in Personal Communications Systems) and the IEEE Journal on Selected Areas in Communications (Multi-media Network Radios). Ramesh R. Rao was born in Sindri, India, where he completed his undergraduate work at the Regional Engineering College of the University of Madras in Tiruchirapalli, obtaining a BE (Honors) degree in Electronics and Communications in 1980. He completed his graduate work at the University of Maryland, College Park, Maryland where he received his M.S. and Ph.D. Professor Rao is currently a Professor at the University of California, San Diego (UCSD) at the department of Electrical and Computer Engineering in the Irwin and Joan Jacobs School of Engineering, where he has been a member of the faculty since 1984. Professor Rao is the former director of UCSD’s Center for Wireless Communications (CWC), and currently serves as the Qualcomm Endowed Chair in Telecommunications and Information Technologies, and as the Director of the San Diego Division of the California Institute of Telecommunications and Information Technology [Cal-(IT)²]. As Director of the San Diego Division of Cal-(IT)², he leads several interdisciplinary and collaborative projects. His research interests include architectures, protocols and performance analysis of computer and communication networks, and he has published extensively on these topics. Since 1984, Professor Rao has authored over 100 technical papers, contributed book chapters, conducted a number of short courses and delivered invited talks and plenary lectures. He is currently supervising both masters and doctoral students.     

Auction-Based Spectrum Sharing

We study auction mechanisms for sharing spectrum among a group of users, subject to a constraint on the interference temperature at a measurement point. The users access the channel using spread spectrum signaling and so interfere with each other. Each user receives a utility that is a function of the received signal-to-interference plus noise ratio. We propose two auction mechanisms for allocating the received power. The first is an auction in which users are charged for received SINR, which, when combined with logarithmic utilities, leads to a weighted max-min fair SINR allocation. The second is an auction in which users are charged for power, which maximizes the total utility when the bandwidth is large enough and the receivers are co-located. Both auction mechanisms are shown to be socially optimal for a limiting “large system” with co-located receivers, where bandwidth, power and the number of users are increased in fixed proportion. We also formulate an iterative and distributed bid updating algorithm, and specify conditions under which this algorithm converges globally to the Nash equilibrium of the auction. This work was supported by the Northwestern-Motorola Center for Communications and by NSF CAREER award CCR-0238382. This paper was presented in part at the 2nd Workshop on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt’04), Cambridge, UK, March 24–26, 2004, and the 42nd Annual Allerton Conference on Communication, Control and Computing, Monticello, IL, USA, September 29 - October 1, 2004. Jianwei Huang received the B.E. degree in Radio Engineering from Southeast University, Nanjing, China in 2000, and the M.S. and Ph.D. degrees in Electrical and Computer Engineering from Northwestern University, Evanston, IL in 2003 and 2005, respectively. He is currently a Postdoc Research Association in the Department of Electrical Engineering, Prinston university, NJ. In 2004 and 2005, he also worked in the Mathematics of Communication Networks Group at Motorola, Arlington Heights, IL USA as a software engineer. His current research interests lie in the areas of wireless and wireline communications networks, with emphases on resource allocation, network pricing, dynamic spectrum sharing, mobile ad hoc and sensor networks, stochastics and non-convex optimizations. Dr. Huang is the receipt of a 2001 Walter P. Murphy Fellowship at Northwestern University, and a 1999 Chinese National Excellent Student Award. Randall A. Berry received the B.S. degree in Electrical Engineering from the University of Missouri-Rolla in 1993 and the M.S. and Ph.D. degrees in Electrical Engineering and Computer Science from the Massachusetts Institute of Technology in 1996 and 2000 respectively. He is currently an assistant professor in the Department of Electrical Engineering and Computer Science at Northwestern University. In 1998 he was on the technical staff at MIT Lincoln Laboratory in the Advanced Networks Group. His primary research interests include wireless communication, data networks, and information theory. He is the recipient of a 2003 NSF CAREER award. Michael L. Honig received the B.S. degree in electrical engineering from Stanford University in 1977, and the M.S. and Ph.D. degrees in electrical engineering from the University of California, Berkeley, in 1978 and 1981, respectively. He subsequently joined Bell Laboratories in Holmdel, NJ, where he worked on local area networks and voiceband data transmission. In 1983 he joined the Systems Principles Research Division at Bellcore, where he worked on Digital Subscriber Lines and wireless communications. Since the Fall of 1994, he has been with Northwestern University where he is a Professor in the Electrical Engineering and Computer Science Department. He has held visiting scholar positions at the Naval Research Laboratory (San Diego), the University of California, Berkeley, the University of Sydney, and Princeton University. He has also worked as a free-lance trombonist. Dr. Honig has served as an editor for the IEEE Transactions on Information Theory (1998-2000) and the IEEE Transactions on Communications (1990-1995), and was a guest editor for the European Transactions on Telecommunications and Wireless Personal Communications. He has also served as a member of the Digital Signal Processing Technical Committee for the IEEE Signal Processing Society, and as a member of the Board of Governors for the Information Theory Society (1997-2002). He is the co-recipient of the 2002 IEEE Communications Society and Information Theory Society Joint Paper Award, and is a Fellow of IEEE.     

FAMOUS: A Network Architecture for Delivering Multimedia Services to FAst MOving USers

When today’s commuters in the train or in a car want to access the Internet, they see themselves restricted to simple web surfing or e-mail. Interactive multimedia services, like online gaming or video conferencing are still unavailable to them, even with promising new technologies like UMTS or WiMAX. The impact of high bit rate multimedia traffic on the access network and aggregation network is an important topic, that has not been addressed in enough detail before. We designed a network architecture for offering these multimedia services to fast moving users. We refer to the overall network architecture as the FAMOUS network architecture, which consists of two parts: (i) an access network part which has to deal with large number of users, asking for a high bandwidth, while experiencing a high handoff frequency and (ii) an aggregation network part which has to deal with dynamic tunnels of very high bandwidth, while experiencing a low handoff frequency. In this paper, we detail the FAMOUS architecture, together with optimized handoff strategies, an optical switching architecture, a design methodology for dimensioning aggregations networks and automatic tunnel pre-configuration and activation. Moreover, performance results of these mentioned aspects will be presented.Filip De Greve was born in Gent, Belgium, in 1978. He received his Master of Science degree in Electrotechnical Engineering from Ghent University, Gent, Belgium in 2001. In 2002, he joined the Department of Information Technology of the Faculty of Applied Sciences, University of Ghent as a doctoral researcher. Besides specific Ethernet-related research topics, his current research interests are related to broadband communication networks and include design, routing and reliability of access and aggregation networks.Bart Lannoo was born in Torhout, Belgium, in 1979. He received his Master of Science degree in Electrotechnical Engineering from Ghent University, Ghent, Belgium in 2002. Since August 2002, he has been working with Department of Information Technology (INTEC) of the Faculty of Applied Sciences, Ghent University as a doctoral researcher. His current research interests are in optical access networks, including both fixed access networks (FTTx) and optical access for wireless communication.Liesbeth Peters received the degree in Electrotechnical Engineering from Ghent University, Belgium in 2001. Since August 2001, she has been working as a doctoral researcher with the Department of Information Technology of Ghent University, where she joined the Broadband Communications Networks Group. Since October 2002, she works there as a research assistant of the Fund for Scientific Research – Flanders (F.W.O.-V., Belgium). Her current research interests are in broadband wireless communication and the support of IP mobility in wired cum wireless networks.Tom Van Leeuwen was born in Gent, Belgium, in 1979. He received his masters degree in Computer Engineering from the Ghent University, Gent, Belgium in 2002. Since 2002, he has been working with Department of Information Technology of Ghent University (INTEC) as a doctoral researcher. In 2004 he received a PhD grant from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). His current research interests are in broadband wireless communication.Frederic Van Quickenborne (M. Sc. Degree in Electrotechnical Engineering, University of Ghent, Belgium, 2002) published different papers on the growing importance of ethernet in aggregation and core networks. Besides his interest in ethernet related topics (QoS, VLANs, xSTP), he is also involved in projects concerning video-streaming and is working on a Click-based ethernet testbed. This research is funded by a PhD grant from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen), that he obtained in 2004.Didier Colle received a M.Sc. degree in electrotechnical engineering (option: communications) from the Ghent University in 1997. Since then, he has been working at the same university as researcher in the department of Information Technology (INTEC). He is part of the research group INTEC Broadband Communication Networks (IBCN) headed by Prof.: Piet Demeester. His research lead to a Ph.D. degree in February 2002. From January 2003 on, he was granted a postdoctoral scholarship from the “Instituut voor de aanmoediging van Innovatie door Wetenschap en Technologie in Vlaanderen (IWT-Vlaanderen)”. His research deals with design and planning of communication networks. His work is focussing on optical transport networks, to support the next-generation Internet. Up till now, he has actively been involved in three IST projects (LION, OPTIMIST and DAVID) and in the COST266 action. His work has been published in more than 40 scientific publications in international conferences and journals.Filip de Turck received his M.Sc. degree in Electronic Engineering from the Ghent University, Belgium, in June 1997. In May 2002, he obtained the Ph.D. degree in Electronic Engineering from the same university. From October 1997 to September 2001, Filip De Turck was research assistant with the Fund for Scientific Research-Flanders, Belgium (F.W.O.-V.). At the moment, he is a part-time professor and a post-doctoral fellow of the F.W.O.-V., affiliated with the Department of Information Technology of the Ghent University. Filip De Turck is author or co-author of approximately 80 papers published in international journals or in the proceedings of international conferences. His main research interests include scalable software architectures for telecommunication network and service management, performance evaluation and optimization of routing, admission control and traffic management in telecommunication systems.Ingrid Moerman was born in Gent, Belgium, in 1965. She received the degree in Electro-technical Engineering and the Ph.D degree from the Ghent University, Gent, Belgium in 1987 and 1992, respectively. Since 1987, she has been with the Interuniversity Micro-Electronics Centre (IMEC) at the Department of Information Technology (INTEC) of the Ghent University, where she conducted research in the field of optoelectronics. In 1997, she became a permanent member of the Research Staff at IMEC. Since 2000 she is part-time professor at the Ghent University. Since 2001 she has switched her research domain to broadband communication networks. She is currently involved in the research and education on broadband mobile & wireless communication networks and on multimedia over IP. She is author or co-author of more than 300 publications in the field of optoelectronics and communication networks.Mario Pickavet received an M.Sc. and Ph.D. degree in electrical engineering, specialized in telecommunications, from Ghent University in 1996 and 1999, respectively. Since 2000, he is professor at Ghent University where he is teaching telecommunication networks and algorithm design. His current research interests are related to broadband communication networks (WDM, IP, (G-)MPLS, OPS, OBS) and include design, long-term planning and routing of core and access networks. In this context, he is currently involved a.o. in the European IST projects “All-Optical Label Swapping Employing Optical Logic Gates in Network Nodes” (LASAGNE) and “Optical Networks: Towards Bandwidth Manageability and Cost Efficiency” (e-Photon/ONe) and in several national research projects. He has published about a hundred international publications, both in journals (e.g. IEEE JSAC, IEEE Comm. Mag., JLT) and in proceedings of conferences. He is one of the authors of the book ‘Network Recovery: Protection and Restoration of Optical, SONET-SDH, IP, and MPLS’.Bart Dhoedt received a degree in Engineering from the Ghent University in 1990. In September 1990, he joined the Department of Information Technology of the Faculty of Applied Sciences, University of Ghent. His research, addressing the use of micro-optics to realize parallel free space optical interconnects, resulted in a PhD degree in 1995. After a 2 year post-doc in opto-electronics, he became professor at the Faculty of Applied Sciences, Department of Information Technology. Since then, he is responsible for several courses on algorithms, programming and software development. His research interests are software engineering and mobile & wireless communications. Bart Dhoedt is author or co-author of approximately 70 papers published in international journals or in the proceedings of international conferences. His current research addresses software technologies for communication networks, peer-to-peer networks, mobile networks and active networks.Piet Demeester finished his PhD thesis at the Department of Information Technology (INTEC) at the Ghent University in 1988. At the same department he became group leader of the activities on Metal Organic Vapour Phase Epitaxial growth for optoelectronic components. In 1992 he started a new research group on Broadband Communication Networks. The research in this field resulted in already more than 300 publications. In this research domain he was and is a member of several programme committees of international conferences, such as: ICCCN, the International Conference on Telecommunication Systems, OFC, ICC, and ECOC. He was Chairman of DRCN’98. In 2001 he was chairman of the Technical Programme Committee ECOC’01. He was Guest Editor of three special issues of the IEEE Communications Magazine. He is also a member of the Editorial Board of the Journals “Optical Networks Magazine” and ldquo;Photonic Network Communications”. He was a member of several national and international PhD thesis commissions. Piet Demeester is a member of IEEE (Senior Member), ACM and KVIV. His current research interests include: multilayer networks, Quality of Service (QoS) in IP-networks, mobile networks, access networks, grid computing, distributed software, network and service management and applications (supported by FWO-Vlaanderen, the BOF of the Ghent University, the IWT and the European Commission). Piet Demeester is currently full-time professor at the Ghent University, where he is teaching courses in Communication Networks. He has also been teaching in different international courses.     

Performance of a burst-frame-based CSMA/CA protocol: Analysis and enhancement

In this paper, we develop an analytical model to evaluate the delay performance of the burst-frame-based CSMA/CA protocol under unsaturated conditions, which has not been fully addressed in the literature. Our delay analysis is unique in that we consider the end-to-end packet delay, which is the duration from the epoch that a packet enters the queue at the MAC layer of the transmitter side to the epoch that the packet is successfully received at the receiver side. The analytical results give excellent agreement with the simulation results, which represents the accuracy of our analytical model. The results also provide important guideline on how to set the parameters of the burst assembly policy. Based on these results, we further develop an efficient adaptive burst assembly policy so as to optimize the throughput and delay performance of the burst-frame-based CSMA/CA protocol. Kejie Lu received the B.E. and M.E. degrees in Telecommunications Engineering from Beijing University of Posts and Telecommunications, Beijing, China, in 1994 and 1997, respectively. He received the Ph.D. degree in Electrical Engineering from the University of Texas at Dallas in 2003. In 2004 and 2005, he was a postdoctoral research associate in the Department of Electrical and Computer Engineering, University of Florida. Currently, he is an assistant professor in the Department of Electrical and Computer Engineering, University of Puerto Rico at Mayagüez. His research interests include architecture and protocols design for computer and communication networks, performance analysis, network security, and wireless communications. Jianfeng Wang received the B.E. and M.E. degrees in electrical engineering from Huazhong University of Science and Technology, China, in 1999 and 2002, respectively, and the Ph.D. degree in electrical engineering from University of Florida in 2006. From January 2006 to July 2006, he was a research intern in wireless standards and technology group, Intel Corporation. In October 2006, he joined Philips Research North America as a senior member research staff in wireless communications and networking department. He is engaged in research and standardization on wireless networks with emphasis on medium access control (MAC). Dapeng Wu received B.E. in Electrical Engineering from Huazhong University of Science and Technology, Wuhan, China, in 1990, M.E. in Electrical Engineering from Beijing University of Posts and Telecommunications, Beijing, China, in 1997, and Ph.D. in Electrical and Computer Engineering from Carnegie Mellon University, Pittsburgh, PA, in 2003. Since August 2003, he has been with Electrical and Computer Engineering Department at University of Florida, Gainesville, FL, as an Assistant Professor. His research interests are in the areas of networking, communications, multimedia, signal processing, and information and network security. He received the IEEE Circuits and Systems for Video Technology (CSVT) Transactions Best Paper Award for Year 2001, and the Best Paper Award in International Conference on Quality of Service in Heterogeneous Wired/Wireless Networks (QShine) 2006. Currently, he serves as the Editor-in-Chief of Journal of Advances in Multimedia, and an Associate Editor for IEEE Transactions on Wireless Communications, IEEE Transactions on Circuits and Systems for Video Technology, IEEE Transactions on Vehicular Technology, and International Journal of Ad Hoc and Ubiquitous Computing. He is also a guest-editor for IEEE Journal on Selected Areas in Communications (JSAC), Special Issue on Cross-layer Optimized Wireless Multimedia Communications. He served as Program Chair for IEEE/ACM First International Workshop on Broadband Wireless Services and Applications (BroadWISE 2004); and as a technical program committee member of over 30 conferences. He is Vice Chair of Mobile and wireless multimedia Interest Group (MobIG), Technical Committee on Multimedia Communications, IEEE Communications Society. He is a member of the Best Paper Award Committee, Technical Committee on Multimedia Communications, IEEE Communications Society. Yuguang Fang received a Ph.D. degree in Systems Engineering from Case Western Reserve University in January 1994 and a Ph.D. degree in Electrical Engineering from Boston University in May 1997. He was an assistant professor in the Department of Electrical and Computer Engineering at New Jersey Institute of Technology from July 1998 to May 2000. He then joined the Department of Electrical and Computer Engineering at University of Florida in May 2000 as an assistant professor and got an early promotion to an associate professor with tenure in August 2003 and to a full professor in August 2005. He has published over 200 papers in refereed professional journals and conferences. He received the National Science Foundation Faculty Early Career Award in 2001 and the Office of Naval Research Young Investigator Award in 2002. He has served on several editorial boards of technical journals including IEEE Transactions on Communications, IEEE Transactions on Wireless Communications, IEEE Transactions on Mobile Computing and ACM Wireless Networks. He have also been actively participating in professional conference organizations such as serving as The Steering Committee Co-Chair for QShine, the Technical Program Vice-Chair for IEEE INFOCOM’2005, Technical Program Symposium Co-Chair for IEEE Globecom’2004, and a member of Technical Program Committee for IEEE INFOCOM (1998, 2000, 2003–2007). He is a senior member of the IEEE.     

A VLSI Implementation of Low Power, Low Data Rate UWB Transceiver for Location and Tracking Applications

A low power, low data rate ultra wideband (UWB) impulse radio transceiver for location and tracking applications is presented in this paper. The UWB receiver is based on a non-coherent, energy collection approach, which makes the receiver highly independent of the shape of the transmitted waveform. The UWB signal is generated by a pulse generator and band-pass filter fixing the signal bandwidth to 1 GHz in the band from 3.1 GHz to 4.1 GHz. The modulation scheme used in this time division multiple access system (TDMA) is Binary Pulse Position Modulation (BPPM). In this paper the system concept, system architecture and RF parts of the VLSI implementation are peresented. The transceiver is implemented in a 0.35 μm SiGe process provided by Austria Microsystems. Sakari Tiuraniemi was born in Kolari, Finland, on March 10, 1977. He received his M.Sc. degree in 2003 in electrical engineering from the University of Oulu, Finland, where he then continued his research on transceiver integration and implementation issues for two years. In 2005 he joined the CERN in Geneva, Switzerland, where he is working towards the PhD degree in electrical engineering. His current research focuses on detector readout electronics for high energy physics applications. Lucian Stoica was born in Roman, Romania, on December 8, 1975. He received the M.S. degree in electrical engineering from the Technical University of Iasi, Romania, in 2000. He was with Telecommunications Department at the Technical University of Iasi from 2000 to 2003. As a teaching assistant he was involved in development of digital design and FPGA prototyping. In 2003, he joined Centre for Wireless Communications, University of Oulu, Oulu, Finland where he is working towards the PhD degree in electrical engineering. His current research focuses on low complexity SiGe BiCMOS circuit transceivers design for wireless communications, particularly on ultrawideband impulse radio systems. Alberto Rabbachin received the M.S. from the University of Bologna, Italy, in 2001. In 2001, during his undergraduate studies, he visited the Centre for Wireless Communications, University of Oulu, Finland. In 2002 he joined Agilent Technologies for an internship and since 2003 he is working towards the PhD degree at the Centre for Wireless Communications. His research interests include UWB systems with emphasis on receiver structures, synchronization and ranging techniques. Ian Oppermann was born in Maryborough, Australia, in 1969. He completed a BSc, BE and PhD at the University of Sydney Australia in 1990, 1992 and 1997, respectively. His PhD was related to physical layer aspects of novel spread spectrum/CDMA systems. In 1996 he founded SP Communications, a company which developed network planning tools for 3G mobile systems and IP cores for WLAN chipsets. He became a Docent (Adjunct Professor) at the University of Oulu, Finland in 2001 and subsequently joined the Centre for Wireless Communications (CWC) in 2002 as Assistant Director, becoming Director in 2003. From the beginning of 2005 is the acting Director for Short Range Communications Research at CWC. His main research interests are spread spectrum systems and UWB. Dr. Oppermann has co-edited several books, holds several patents for wireless communications and has over 80 publications in international journals and conferences.     

QoS Aware Multi-Channel Scheduling for IEEE 802.15.3 Networks

From a multimedia applications perspective, there is an ever increasing demand for wireless devices with higher bandwidth to support high data rate flows. One possible solution to support the demand for higher bandwidth is to utilize the full spectrum by simultaneously using multiple channels for transmission. Recent approval by the Federal Communications Commission (FCC) has led to considerable interest in exploiting Ultra Wideband (UWB) access on an unlicensed basis in the 3.1--10.6 GHz band. Currently, the IEEE TG802.15.3a standards group is in the process of developing an alternative high-speed link layer design conformable with the IEEE 802.15.3 Wireless Personal Area Network (WPAN) multiple access (MAC) protocol. One of the proposals, based on the concept of Orthogonal Frequency Division Multiplexing (OFDM), divides the spectrum into multiple bands and achieves channelization through the use of different time-frequency codes. These multiple channels can help satisfy the increasing demand for higher bandwidth in order to support high data rate multimedia applications. In this paper, we present a QoS-aware, multi-channel scheduling algorithm that simultaneously utilizes the various channels available in the UWB network. Aniruddha Rangnekar is a doctoral student in the Department of Computer Science and Electrical Engineering at the University of Maryland, Baltimore County. He received the B.E. degree in Computer Engineering from the University of Pune, India in 1998 and a M.S. in Computer Science from the University of Maryland, Baltimore County in 2001. From January 2002 to date, he has been involved in graduate research in University of Maryland, Baltimore County. During the summer of 2004, he worked as the MAC development engineer at Staccato Communications, San Diego, CA. His current interests are in the areas of wireless ad hoc networks, multicast routing protocols, ultra wideband communications and MAC protocol development. He is a member of the MACSim group of the Multiband OFDM alliance (MBOA). Krishna M. Sivalingam is an Associate Professor in the Dept. of CSEE at University of Maryland, Baltimore County. Previously, he was with the School of EECS at Washington State University, Pullman from 1997 until 2002; and with the University of North Carolina Greensboro from 1994 until 1997. He has also conducted research at Lucent Technologies' Bell Labs in Murray Hill, NJ, and at AT&T Labs in Whippany, NJ. He received his Ph.D. and M.S. degrees in Computer Science from State University of New York at Buffalo in 1994 and 1990 respectively; and his B.E. degree in Computer Science and Engineering in 1988 from Anna University, Chennai (Madras), India. While at SUNY Buffalo, he was a Presidential Fellow from 1988 to 1991. His research interests include wireless networks, optical wavelength division multiplexed networks, and performance evaluation. He holds three patents in wireless networks and has published several research articles including more than thirty journal publications. He has published an edited book on Wireless Sensor Networks in 2004 and edited books on optical WDM networks in 2000 and 2004. He served as a Guest Co-Editor for special issues of the ACM MONET journal on “Wireless Sensor Networks” in 2003 and 2004; and an issue of the IEEE Journal on Selected Areas in Communications on optical WDM networks (2000). He is co-recipient of the Best Paper Award at the IEEE International Conference on Networks 2000 held in Singapore. His work has been supported by several sources including AFOSR, NSF, Cisco, Intel and Laboratory for Telecommunication Sciences. He is a member of the Editorial Board for ACM Wireless Networks Journal, IEEE Transactions on Mobile Computing, Ad Hoc and Sensor Wireless Networks Journal, and KICS Journal of Computer Networks. He serves as Steering Committee Co-Chair for the International Conference on Broadband Networks (BroadNets) that was created in 2004. He is currently serving as General Co-Vice-Chair for the Second Annual International Mobiquitous conference to be held in San Diego in 2005 and as General Co-Chair for the First International Conference on Security and Privacy for Emerging Areas in Communication Networks to be held in Athens, Greece in Sep. 2005. He served as Technical Program Co-Chair for the First IEEE Conference on Sensor and Ad Hoc Communications and Networks (SECON) held at Santa Clara, CA in 2004; as General Co-Chair for SPIE Opticomm 2003 (Dallas, TX) and for ACM Intl. Workshop on Wireless Sensor Networks and Applications (WSNA) 2003 held in conjunction with ACM MobiCom 2003 at San Diego, CA; as Technical Program Co-Chair of SPIE/IEEE/ACM OptiComm conference at Boston, MA in July 2002; and as Workshop Co-Chair for WSNA 2002 held in conjunction with ACM MobiCom 2002 at Atlanta, GA in Sep 2002. He is a Senior Member of IEEE and a member of ACM.     

Lightweight Deployment-Aware Scheduling for Wireless Sensor Networks

Wireless sensor networks consist of a large number of tiny sensors that have only limited energy supply. One of the major challenges in constructing such networks is to maintain long network lifetime as well as sufficient sensing areas. To achieve this goal, a broadly-used method is to turn off redundant sensors. In this paper, the problem of estimating redundant sensing areas among neighbouring wireless sensors is analysed. We present simple methods to estimate the degree of redundancy without the knowledge of location or directional information. We also provide tight upper and lower bounds on the probability of complete redundancy and on the average partial redundancy. With random sensor deployment, our analysis shows that partial redundancy is more realistic for real applications, as complete redundancy is expensive, requiring up to 11 neighbouring sensors to provide a 90 percent chance of complete redundancy. Based on the analysis, we propose a scalable Lightweight Deployment-Aware Scheduling (LDAS) algorithm, which turns off redundant sensors without using accurate location information. Simulation study demonstrates that the LDAS algorithm can reduce network energy consumption and provide desired QoS requirement effectively. This research was partially supported by Natural Sciences and Engineering Research Council of Canada. Kui Wu received his Ph.D. in Computing Science from the University of Alberta, Canada, in 2002. He joined the Department of Computer Science at the University of Victoria, Canada in the same year and is currently an Assistant Professor there. His research interests include mobile and wireless networks, network performance evaluation, and network security. Yong Gao received his Master's degree and Ph.D. degree in computer science from University of Alberta, Canada, in 2000 and 2005 respectively. He is currently with the Irving K. Barber School of Arts and Sciences, UBC Okanagan, Canada. His research interests include search algorithms and AI, communication networks, and computational biology. Yang Xiao worked at Micro Linear as an MAC (Medium Access Control) architect involving the IEEE 802.11 standard enhancement work before he joined Department of Computer Science at The University of Memphis in 2002. Dr. Xiao is an IEEE Senior member. He was a voting member of IEEE 802.11 Working Group from 2001 to 2004. He currently serves as Editor-in-Chief for International Journal of Security and Networks (IJSN) and for International Journal of Sensor Networks (IJSNet). He serves as an associate editor or on editorial boards for the following refereed journals: (Wiley) International Journal of Communication Systems, (Wiley) Wireless Communications and Mobile Computing (WCMC), EURASIP Journal on Wireless Communications and Networking, and International Journal of Wireless and Mobile Computing. He serves as five lead/sole guest editor for five journal special issues. He serves as a referee/reviewer for many funding agencies, as well as a panelist for NSF. His research interests are Security/ Reliable Communications, Medium Access Control, Mobility/Location/Paging Managements, Cache Access and Replacement Policies, Quality of Service, Energy Efficiency, and Routing in wireless networks and mobile computing.     

Energy-aware on-demand routing protocols for wireless ad hoc networks

Energy use is a crucial design concern in wireless ad hoc networks since wireless terminals are typically battery-operated. The design objectives of energy-aware routing are two folds: Selecting energy-efficient paths and minimizing the protocol overhead incurred for acquiring such paths. To achieve these goals simultaneously, we present the design of several on-demand energy-aware routing protocols. The key idea behind our design is to adaptively select the subset of nodes that are required to involve in a route-searching process in order to acquire a high residual-energy path and/or the degree to which nodes are required to participate in the process of searching for a low-power path in networks wherein nodes have transmission power adjusting capability. Analytical and simulation results are given to demonstrate the high performance of the designed protocols in energy-efficient utilization as well as in reducing the protocol overhead incurred in acquiring energy-efficient routes. Baoxian Zhang received his B.S., M.S., and Ph.D. degrees in Electrical Engineering from Northern Jiaotong University, Beijing, China in 1994, 1997, and 2000, respectively. From January 2001 to August 2002, he was working with Department of Electrical and Computer Engineering at Queen’s University in Kingston as a postdoctoral fellow. He is currently a research scientist with the School of Information Technology and Engineering (SITE) of University of Ottawa in Ottawa, Ontario, Canada. He has published over 40 refereed technical papers in international journals and conference proceedings. His research interests include routing algorithm and protocol design, QoS management, wireless ad hoc and sensor networks, survivable optical networks, multicast communications, and performance evaluation. He is a member of the IEEE. Hussein Mouftah joined the School of Information Technology and Engineering (SITE) of the University of Ottawa in September 2002 as a Canada Research Chair (Tier 1) Professor in Optical Networks. He has been with the Department of Electrical and Computer Engineering at Queen’s University (1979-2002), where he was prior to his departure a Full Professor and the Department Associate Head. He has three years of industrial experience mainly at Bell Northern Research of Ottawa, now Nortel Networks (1977-79). He has spent three sabbatical years also at Nortel Networks (1986-87, 1993-94, and 2000-01), always conducting research in the area of broadband packet switching networks, mobile wireless networks and quality of service over the optical Internet. He served as Editor-in-Chief of the IEEE Communications Magazine (1995-97) and IEEE Communications Society Director of Magazines (1998-99) and Chair of the Awards Committee (2002-2003). He is a Distinguished Speaker of the IEEE Communications Society since 2000. Dr. Mouftah is the author or coauthor of five books, 22 book chapters and more than 700 technical papers and 8 patents in this area. He is the recipient of the 1989 Engineering Medal for Research and Development of the Association of Professional Engineers of Ontario (PEO), and the Ontario Distinguished Researcher Award of the Ontario Innovation Trust. He is the joint holder of the Best Paper Award for a paper presented at SPECTS’2002, and the Outstanding Paper Award for papers presented at the IEEE HPSR’2002 and the IEEE ISMVL’1985. Also he is the joint holder of a Honorable Mention for the Frederick W. Ellersick Price Paper Award for Best Paper in the IEEE Communications Magazine in 1993. He is the recipient of the IEEE Canada (Region 7) Outstanding Service Award (1995). Also he is the recipient of the 2004 IEEE Communications Society Edwin Howard Armstrong Achievement Award, and the 2004 George S. Glinski Award for Excellence in Research of the Faculty of Engineering, University of Ottawa. Dr. Mouftah is a Fellow of the IEEE (1990) and Fellow of the Canadian Academy of Engineering (2003).     

Proportional fair throughput allocation in multirate IEEE 802.11e wireless LANs

Under heterogeneous radio conditions, Wireless LAN stations may use different modulation schemes, leading to a heterogeneity of bit rates. In such a situation, 802.11 DCF allocates the same throughput to all stations independently of their transmitting bit rate; as a result, the channel is used by low bit rate stations most of the time, and efficiency is low. In this paper, we propose a more efficient throughput allocation criterion based on proportional fairness. We find out that, in a proportional fair allocation, the same share of channel time is given to high and low bit rate stations, and, as a result, high bit rate stations obtain more throughput. We propose two schemes of the upcoming 802.11e standard to achieve this allocation, and compare their delay and throughput performance. Albert Banchs received his M.Sc. and Ph.D. degrees in Telecommunications from the Technical University of Catalonia in 1997 and 2002, respectively. His Ph.D. received the national award for best thesis on Broadband Networks granted by the Professional Association of Telecommunication Engineers. He worked for the International Computer Science Institute, Berkeley, in 1997, for Telefonica I+D, Madrid, in 1998 and for NEC Network Laboratories, Heidelberg, from 1998 to 2003. Since 2003 he is with the University Carlos III of Madrid. Dr. Banchs is Associate Editor of IEEE Communications Letters and has been TPC member of several conferences and workshops including INFOCOM, ICC, GLOBECOM and QoS-IP. His current research interests include resource allocation, QoS and performance evaluation of wireless and wired networks. Pablo Serrano was born in Tarifa, Spain, on May 17, 1979. He received a M.Sc. degree in Telecommunications from the University Carlos III of Madrid in 2002. Since that date he is a Ph.D. candidate and a lecturer at the Telematics Department of the same university. His current research interests are performance evaluation and resource allocation of WLAN networks. Huw Edward Oliver received his MA degree in Mathematics at Cambridge University (1980), and his MSc (1985) and PhD (1988) in Computer Science at the University College of Wales, Aberystwyth. He joined Hewlett-Packard Laboratories, Bristol in 1989 to work on Software Development Environments. Following a period at HP’s Software Engineering Systems, Colorado in 1992 he returned to HP Labs in 1993 as Senior Member of Technical Staff and worked on real-time fault tolerant telecommunication systems. From 1997 to 2000 he was appointed Manager of Hewlett-Packard’s Internet Research Institute. He worked as Technical Director of the European MMAPPS Project from 2000 to 2002, as Senior Research Fellow at Lancaster University from 2002 to 2004, and as Visiting Professor at University Carlos III of Madrid from 2004 to 2005. Since 2005 he has been Senior Researcher with Ericsson R&D Ireland, Athlone where he is responsible for the next-generation network management architecture.     

HISNs: Distributed gateways for application-level integration of heterogeneous wireless networks

Integration of different kinds of wireless networks to provide people seamless and continuous network access services is a major issue in the B3G network. In this paper, we propose and implement a novel Heterogeneous network Integration Support Node design (HISN) and a distributed HISN network architecture for the integration of heterogeneous networks, under which the Session Mobility, Personal Mobility, and Terminal Mobility for mobile users can be maintained through the Session Management mechanism. Thus, the HISN node can serve as an agent for the user to access Internet services independent of underlying communication infrastructure. Our design is transparent to the bearer networks and the deployment of the HISN network does not need to involve the operators of the heterogeneous wireless networks. This paper is an extension of the work that won the championship of the Mobile Hero contest sponsored by Industrial Development Bureau of Ministry of Economic Affairs, Taiwan, R.O.C., and was awarded USD 30,000. The work of Lin, Chang and Cheng was supported in part by the National Science Council (NSC), R.O.C, under the contract number NSC94-2213-E-002-083 and NSC94-2213-E-002-090, and NSC 94-2627-E-002-001, Ministry of Economic Affairs (MOEA), R.O.C., under contract number 93-EC-17-A-05-S1-0017, the Computer and Communications Researches Labs/Industrial Technology Research Institute (CCL/ITRL), Chunghwa Telecom Labs, Telcordia Applied Research Center, Taiwan Network Information Center (TWNIC), and Microsoft Corporation, Taiwan. The work of Fang was supported in part by the US National Science Foundation Faculty Early Career Development Award under grant ANI-0093241 and US National Science Foundation under grant DBI-0529012. Phone Lin (M’02-SM’06) received his BSCSIE degree and Ph.D. degree from National Chiao Tung University, Taiwan, R.O.C. in 1996 and 2001, respectively. From August 2001 to July 2004, he was an Assistant Professor in Department of Computer Science and Information Engineering (CSIE), National Taiwan University, R.O.C. Since August 2004, he has been an Associate Professor in Department of CSIE and Graduate Institute of Networking and Multimedia, National Taiwan University, R.O.C. His current research interests include personal communications services, wireless Internet, and performance modeling. Dr. Lin is an Associate Editor for IEEE Transactions on Vehicular Technology, a Guest Editor for IEEE Wireless Communications special issue on Mobility and Resource Management, and a Guest Editor for ACM/Springer MONET special issue on Wireless Broad Access. He is also an Associate Editorial Member for the WCMC Journal. P. Lin’s email and website addresses are plin@csie.ntu.edu.tw and http://www.csie.ntu.edu.tw/∼plin, respectively. Huan-Ming Chang received the BSCSIE degree and Master CSIE degree from National Taiwan University, R.O.C. in 2003 and 2005, respectively. His current research interest includes wireless Internet. H.-M. Chang’s email address is r91114@csie.ntu.edu.tw. Yuguang Fang received a Ph.D. degree in Systems and Control Engineering from Case Western Reserve University in January 1994, and a Ph.D. degree in Electrical Engineering from Boston University in May 1997. From June 1997 to July 1998, he was a Visiting Assistant Professor in Department of Electrical Engineering at the University of Texas at Dallas. From July 1998 to May 2000, he was an Assistant Professor in the Department of Electrical and Computer Engineering at New Jersey Institute of Technology. In May 2000, he joined the Department of Electrical and Computer Engineering at University of Florida where he got the early promotion to Associate Professor with tenure in August 2003 and to Full Professor in August 2005. He has published over 180 papers in refereed professional journals and conferences. He received the National Science Foundation Faculty Early Career Award in 2001 and the Office of Naval Research Young Investigator Award in 2002. He is currently serving as an Editor for many journals including IEEE Transactions on Communications, IEEE Transactions on Wireless Communications, IEEE Transactions on Mobile Computing, and ACM Wireless Networks. He is also actively participating in conference organization such as the Program Vice-Chair for IEEE INFOCOM’2005, Program Co-Chair for the Global Internet and Next Generation Networks Symposium in IEEE Globecom’2004 and the Program Vice Chair for 2000 IEEE Wireless Communications and Networking Conference (WCNC’2000). Shin-Ming Cheng received the BSCSIE degree in 2000 from National Taiwan University, Taiwan, R.O.C., where he is currently working toward the Ph.D. degree in the Department of Computer Science and Information Engineering, National Taiwan University. His current research interests include mobile computing, personal communications services, and wireless Internet. S.-M. Cheng’s email and website addresses are shimi@pcs.csie.ntu.edu.tw and http://www.pcs.csie.ntu.edu.tw/∼shimi, respectively.     

Channel Sharing Scheme for Packet-Switched Cellular Networks

In this paper, we study an approach for sharing channels to improve network utilization in packet-switched cellular networks. Our scheme exploits unused resources in neighboring cells without the need for global coordination. We formulate a minimax approach to optimizing the allocation of channels in this sharing scheme. We develop a measurement-based distributed algorithm to achieve this objective and study its convergence. We illustrate, via simulation results, that the distributed channel sharing scheme performs significantly better than the fixed channel scheme over a wide variety of traffic conditions. This research was supported in part by the National Science Foundation through grants ECS-0098089, ANI-0099137, ANI-0207892, ANI-9805441, ANI-0099137, and ANI-0207728, and by an Indiana 21st century grant. A conference version of this paper appeared in INFOCOM 99. This work was done when all the authors were at Purdue University. Suresh Kalyanasundaram received his Bachelors degree in Electrical and Electronics Engineering and Masters degree in Physics from Birla Institute of Technology and Science, Pilani, India in 1996. He received his Ph.D. from the School of Electrical and Computer Engineering, Purdue University, in May 2000. Since then he has been with Motorola, working in the area of performance analysis of wireless networks. Junyi Li received his B.S. and M.S. degrees from Shanghai Jiao Tong University, and Ph.D. degree from Purdue University. He was with the Department of Digital Communications Research at Bell Labs, Lucent Technologies from 1998 to 2000. In 2000 as a founding member he jointed Flarion Technologies, where he is now Director of Technology. He is a senior member of IEEE. Edwin K.P. Chong received the B.E.(Hons.) degree with First Class Honors from the University of Adelaide, South Australia, in 1987; and the M.A. and Ph.D. degrees in 1989 and 1991, respectively, both from Princeton University, where he held an IBM Fellowship. He joined the School of Electrical and Computer Engineering at Purdue University in 1991, where he was named a University Faculty Scholar in 1999, and was promoted to Professor in 2001. Since August 2001, he has been a Professor of Electrical and Computer Engineering and a Professor of Mathematics at Colorado State University. His current interests are in communication networks and optimization methods. He coauthored the recent book, An Introduction to Optimization, 2nd Edition, Wiley-Interscience, 2001. He was on the editorial board of the IEEE Transactions on Automatic Control, and is currently an editor for Computer Networks. He is an IEEE Control Systems Society Distinguished Lecturer. He received the NSF CAREER Award in 1995 and the ASEE Frederick Emmons Terman Award in 1998. Ness B. Shroff received his Ph.D. degree from Columbia University, NY in 1994. He is currently an Associate Professor in the School of Electrical and Computer Engineering at Purdue University. His research interests span the areas of wireless and wireline communication networks. He is especially interested in fundamental problems in the design, performance, scheduling, capacity, pricing, and control of these networks. His research is funded by various companies such as Intel, Hewlett Packard, Nortel, AT&T, and L. G. Electronics; and government agencies such as the National Science Foundation, Indiana Dept. of Transportation, and the Indiana 21st Century fund. Dr. Shroff is an editor for IEEE/ACM Trans. on Networking and the Computer Networks Journal, and past editor of IEEE Communications Letters. He was the conference chair for the 14th Annual IEEE Computer Communications Workshop (in Estes Park, CO, October 1999) and program co-chair for the symposium on high-speed networks, Globecom 2001 (San Francisco, CA, November 2000). He is also the Technical Program co-chair for IEEE INFOCOM'03 and panel co-chair for ACM Mobicom'02. He received the NSF CAREER award in 1996.