A secure incentive protocol for mobile ad hoc networks

The proper functioning of mobile ad hoc networks depends on the hypothesis that each individual node is ready to forward packets for others. This common assumption, however, might be undermined by the existence of selfish users who are reluctant to act as packet relays in order to save their own resources. Such non-cooperative behavior would cause the sharp degradation of network throughput. To address this problem, we propose a credit-based Secure Incentive Protocol (SIP) to stimulate cooperation among mobile nodes with individual interests. SIP can be implemented in a fully distributed way and does not require any pre-deployed infrastructure. In addition, SIP is immune to a wide range of attacks and is of low communication overhead by using a Bloom filter. Detailed simulation studies have confirmed the efficacy and efficiency of SIP. This work was supported in part by the U.S. Office of Naval Research under Young Investigator Award N000140210464 and under grant N000140210554. Yanchao Zhang received the B.E. degree in Computer Communications from Nanjing University of Posts and Telecommunications, Nanjing, China, in July 1999, and the M.E. degree in Computer Applications from Beijing University of Posts and Telecommunications, Beijing, China, in April 2002. Since September 2002, he has been working towards the Ph.D. degree in the Department of Electrical and Computer Engineering at the University of Florida, Gainesville, Florida, USA. His research interests are network and distributed system security, wireless networking, and mobile computing, with emphasis on mobile ad hoc networks, wireless sensor networks, wireless mesh networks, and heterogeneous wired/wireless networks. Wenjing Lou is an assistant professor in the Electrical and Computer Engineering department at Worcester Polytechnic Institute. She obtained her Ph.D degree in Electrical and Computer Engineering from University of Florida in 2003. She received the M.A.Sc degree from Nanyang Technological University, Singapore, in 1998, the M.E degree and the B.E degree in Computer Science and Engineering from Xi'an Jiaotong University, China, in 1996 and 1993 respectively. From Dec 1997 to Jul 1999, she worked as a Research Engineer in Network Technology Research Center, Nanyang Technological University. Her current research interests are in the areas of ad hoc and sensor networks, with emphases on network security and routing issues. Wei Liu received his B.E. and M.E. in Electrical and Information Engineering from Huazhong University of Science and Technology, Wuhan, China, in 1998 and 2001. In August 2005, he received his PhD in Electrical and Computer Engineering from University of Florida. Currently, he is a senior technical member with Scalable Network Technologies. His research interest includes cross-layer design, and communication protocols for mobile ad hoc networks, wireless sensor networks and cellular networks. 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, got an early promotion to an associate professor with tenure in August 2003 and a professor in August 2005. He has published over 150 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 many 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 is a senior member of the IEEE.     

Signal threshold adaptation for vertical handoff in heterogeneous wireless networks

The convergence of heterogeneous wireless access technologies has been envisioned to characterize the next generation wireless networks. In such converged systems, the seamless and efficient handoff between different access technologies (vertical handoff) is essential and remains a challenging problem. The heterogeneous co-existence of access technologies with largely different characteristics results in handoff asymmetry that differs from the traditional intra-network handoff (horizontal handoff) problem. In the case where one network is preferred, the vertical handoff decision should be carefully executed, based on the wireless channel state, network layer characteristics, as well as application requirements. In this paper, we study the performance of vertical handoff using the integration of 3G cellular and wireless local area networks as an example. In particular, we investigate the effect of an application-based signal strength threshold on an adaptive preferred-network lifetime-based handoff strategy, in terms of the signalling load, available bandwidth, and packet delay for an inter-network roaming mobile. We present an analytical framework to evaluate the converged system performance, which is validated by computer simulation. We show how the proposed analytical model can be used to provide design guidelines for the optimization of vertical handoff in the next generation integrated wireless networks. This article is the extended version of a paper presented in IFIP Networking 2005 Ahmed H. Zahran is a Ph.D. candidate at the Department of Electrical and Computer Engineering, University of Toronto. He received both his M.Sc. and B.Sc. in Electrical Engineering from Electronics and Electrical Communication Department in the Faculty of Engineering, Cairo University in 2002 and 2000 respectively, where he was holding teaching and research positions. Since September 2003, he has been working as a research assistant in the Department of Electrical and Computer Engineering, University of Toronto under the supervision of Professor Ben Liang. His research interest is wireless communication and networking with an emphasis on the design and analysis of networking protocols and algorithms. Ben Liang received honors simultaneous B.Sc. (valedictorian) and M.Sc. degrees in Electrical Engineering from Polytechnic University in Brooklyn, New York, in 1997 and the PhD degree in Electrical Engineering with Computer Science minor from Cornell University in Ithaca, New York, in 2001. In the 2001–2002 academic year, he was a visiting lecturer and post-doctoral research associate at Cornell University. He joined the Department of Electrical and Computer Engineering at the University of Toronto as an Assistant Professor in 2002. His current research interests are in the areas of mobile networking and wireless multimedia systems. He is a member of Tau Beta Pi, IEEE, and ACM and serves on the organization and technical program committees of a number of major conferences each year. Aladdin Saleh earned his Ph.D. degree in Electrical Engineering from London University, England. Since March 1998, Dr. Saleh has been working in the Wireless Technology Department of Bell Canada, the largest service provider of wireless, wire-line, and Internet in Canada. He worked as a senior application architect in the wireless data group working on several projects among them the wireless application protocol (WAP) and the location-based services. Later, he led the work on several key projects in the broadband wireless network access planning group including planning of the IEEE 802.16/ Wimax, the IEEE 802.11/ WiFi, and the integration of these technologies with the 3G cellular network including Mobile IP (MIP) deployment. Dr. Saleh also holds the position of Adjunct Full Professor at the Department of Electrical and Computer Engineering of Waterloo University, Canada since January 2004. He is currently conducting several joint research projects with the University of Waterloo and the University of Toronto on IEEE 802.16-Wimax, MIMO technology, interworking of IEEE 802.11 WLAN and 3G cellular networks, and next generation wireless networks. Prior to joining Bell Canada, Dr. Saleh worked as a faculty member at different universities and was Dean and Chairman of Department for several years. Dr. Saleh is a Fellow of IEE and a Senior Member of IEEE.     

Probabilistic Power Management for Wireless Ad Hoc Networks

Extending system lifetime by effectively managing power on participating nodes is critical in wireless ad hoc networks. Recent work has shown that, by appropriately powering off nodes, energy may be significantly saved up to a factor of two, especially when node density is high. Such approaches rely on the selection of a virtual backbone (i.e., a connected dominating set) of the topology to forward ongoing traffic, coupled with algorithms to manually and periodically recompute such a backbone for load balancing purposes. The common drawback of such schemes is the need to involve periodic message exchanges and to make additional restrictive assumptions. This paper presents Odds¹, an integrated set of energy-efficient and fully distributed algorithms for power management in wireless ad hoc networks. Odds build on the observation that explicit and periodic re-computation of the backbone topology is costly with respect to its additional bandwidth overhead, especially when nodes are densely populated or highly mobile. Building on a fully probabilistic approach, Odds seek to make a minimum overhead, perfectly balanced, and fully localized decision on each node with respect to when and how long it needs to enter standby mode to conserve energy. Such a decision does not rely on periodic message broadcasts in the local neighborhood, so that Odds are scalable as node density increases. Detailed mathematical analysis, discussions and simulation results have shown that Odds are indeed able to achieve our objectives while operating in a wide range of density and traffic loads.Zongpeng Li received his B.Engr. in 1999, from Department of Computer Science and Technology, Tsinghua University, China, and his M.S. degree in 2001 from the Department of Computer Science, University of Toronto. He is currently working towards his Ph.D. degree in the Department of Electrical and Computer Engineering, University of Toronto. His research interests include algorithm design and analysis for both wireless and wireline networks.Baochun Li received his B.Engr. degree in 1995 from Department of Computer Science and Technology, Tsinghua University, China, and his M.S. and Ph.D. degrees in 1997 and 2000 from the Department of Computer Science, University of Illinois at Urbana-Champaign. Since 2000, he has been with the Department of Electrical and Computer Engineering at the University of Toronto, where he is an Assistant Professor. In 2000, he was the recipient of the IEEE Communications Society Leonard G. Abraham Award in the Field of Communications Systems. His research interests include network-level and application-level Quality of Service provisioning, application-layer overlay networks, wireless ad hoc networks, and mobile computing.     

Cross-layer optimization for end-to-end rate allocation in multi-radio wireless mesh networks

In this paper, we study rate allocation for a set of end-to-end communication sessions in multi-radio wireless mesh networks. We propose cross-layer schemes to solve the joint rate allocation, routing, scheduling, power control and channel assignment problems with the goals of maximizing network throughput and achieving certain fairness. Fairness is addressed using both a simplified max-min fairness model and the well-known proportional fairness model. Our schemes can also offer performance upper bounds such as an upper bound on the maximum throughput. Numerical results show that our proportional fair rate allocation scheme achieves a good tradeoff between throughput and fairness. Jian Tang is an assistant professor in the Department of Computer Science at Montana State University. He received the Ph.D. degree in Computer Science from Arizona State University in 2006. His research interest is in the area of wireless networking and mobile computing. He has served on the technical program committees of multiple international conferences, including ICC, Globecom, IPCCC and QShine. He will also serve as a publicity co-chair of International Conference on Autonomic Computing and Communication Systems (Autonomics’2007). Guoliang Xue is a Full Professor in the Department of Computer Science and Engineering at Arizona State University. He received the Ph.D. degree in Computer Science from the University of Minnesota in 1991 and has held previous positions at the Army High Performance Computing Research Center and the University of Vermont. His research interests include efficient algorithms for optimization problems in networking, with applications to fault tolerance, robustness, and privacy issues in networks ranging from WDM optical networks to wireless ad hoc and sensor networks. He has published over 150 papers in these areas. His research has been continuously supported by federal agencies including NSF and ARO. He is the recipient of an NSF Research Initiation Award in 1994 and an NSF-ITR Award in 2003. He is an Associate Editor of Computer Networks (COMNET), the IEEE Network Magazine, and Journal of Global Optimization. He has served on the executive/program committees of many IEEE conferences, including INFOCOM, SECON, IWQOS, ICC, GLOBECOM and QShine. He is the General Chair of IEEE IPCCC’2005, a TPC co-Chair of IPCCC’2003, HPSR’2004, IEEE Globecom’2006 Symposium on Wireless Ad Hoc and Sensor Networks, IEEE ICC’2007 Symposium on Wireless Ad Hoc and Sensor Networks, and QShine’2007. He is a senior member of IEEE. Weiyi Zhang received the M.E. degree in 1999 from Southeast University, China. Currently he is a Ph.D. student in the Department of Computer Science and Engineering at Arizona State University. His research interests include reliable communication in networking, protection and restoration in WDM networks, and QoS provisioning in communication networks.     

Statistical multiplexing, admission region, and contention window optimization in multiclass wireless LANs

This paper presents an analytical model for evaluating the statistical multiplexing effect, admission region, and contention window design in multiclass wireless local area networks (WLANs). We consider distributed medium access control (MAC) which provisions service differentiation by assigning different contention windows to different classes. Mobile nodes belonging to different classes may have heterogeneous traffic arrival processes with different quality of service (QoS) requirements. With bursty input traffic, e.g. on/off sources, our analysis shows that the WLAN admission region under the QoS constraint can be significantly improved, when the statistical multiplexing effect is taken into account. We also analyze the MAC resource sharing between the short-range dependent (SRD) on/off sources and the long-range dependent (LRD) fractional Brownian motion (FBM) traffic, where the impact of the Hurst parameter on the admission region is investigated. Moveover, we demonstrate that the proper selection of contention windows plays an important role in improving the WLAN’s QoS capability, while the optimal contention window for each class and the maximum admission region can be jointly solved in our analytical model. The analysis accuracy and the resource utilization improvement from statistical multiplexing gain and contention window optimization are demonstrated by extensive numerical results. Yu Cheng received the B.E. and M.E. degrees in Electrical Engineering from Tsinghua University, Beijing, China, in 1995 and 1998, respectively, and the Ph.D. degree in Electrical and Computer Engineering from the University of Waterloo, Waterloo, Ontario, Canada, in 2003. From September 2004 to July 2006, he was a postdoctoral research fellow in the Department of Electrical and Computer Engineering, University of Toronto, Ontario, Canada. Since August 2006, he has been with the Department of Electrical and Computer Engineering, Illinois Institute of Technology, Chicago, Illinois, USA, as an Assistant Professor. His research interests include service and application oriented networking, autonomic network management, Internet performance analysis, resource allocation, wireless networks, and wireless/wireline interworking. He received a Postdoctoral Fellowship Award from the Natural Sciences and Engineering Research Council of Canada (NSERC) in 2004. Xinhua Ling received the B. Eng. degree in Radio Engineering from Southeast University, Nanjing, China in 1993 and the M. Eng. degree in Electrical Engineering from the National University of Singapore, Singapore in 2001. He is currently pursuing the Ph.D. degree in the Department of Electrical and Computer Engineering at the University of Waterloo, Ontario, Canada. From 1993 to 1998, he was an R&D Engineer in Beijing Institute of Radio Measurement, China. From February 2001 to September 2002, he was with the Centre for Wireless Communications (currently Institute for Infocom Research), Singapore, as a Senior R&D Engineer, developing the protocol stack for UE in the UMTS system. His general research interests are in the areas of cellular, WLAN, WPAN, mesh and ad hoc networks and their internetworking, focusing on protocol design and performance analysis. Lin X. Cai received the B.Sc. degree in computer science from Nanjing University of Science and Technology, Nanjing, China, in 1996 and the MASc. degree in electrical and computer engineering from the University of Waterloo, Waterloo, Canada, in 2005. She is currently working toward the Ph.D. degree in the same field at the University of Waterloo. Her current research interests include network performance analysis and protocol design for multimedia applications over wireless networks. Wei Song received the B.S. degree in electrical engineering from Hebei University, China, in 1998 and the M.S. degree in computer science from Beijing University of Posts and Telecommunications, China, in 2001. She is currently working toward the Ph.D. degree at the Department of Electrical and Computer Engineering, University of Waterloo, Canada. Her current research interests include resource allocation and quality-of-service (QoS) provisioning for the integrated cellular networks and wireless local area networks (WLANs). Weihua Zhuang received the Ph.D. degree in electrical engineering from the University of New Brunswick, Canada. Since October 1993, she has been with the Department of Electrical and Computer Engineering, University of Waterloo, Canada, where she is a Professor. Dr. Zhuang is a co-author of the textbook Wireless Communications and Networking (Prentice Hall, 2003). Her current research interests include multimedia wireless communications, wireless networks, and radio positioning. She received the Outstanding Performance Award in 2005 and 2006 from the University of Waterloo and the Premier’s Research Excellence Award in 2001 from the Ontario Government for demonstrated excellence of scientific and academic contributions. She is the Editor-in-Chief of IEEE Transactions on Vehicular Technology and an Editor of IEEE Transactions on Wireless Communications. Xuemin (Sherman) Shen received the B.Sc.(1982) degree from Dalian Maritime University (China) and the M.Sc. (1987) and Ph.D. degrees (1990) from Rutgers University, New Jersey (USA), all in electrical engineering. He is a Professor and the Associate Chair for Graduate Studies, Department of Electrical and Computer Engineering, University of Waterloo, Canada. His research focuses on mobility and resource management in interconnected wireless/wired networks, UWB wireless communications systems, wireless security, and ad hoc and sensor networks. He is a co-author of three books, and has published more than 300 papers and book chapters in wireless communications and networks, control and filtering. Dr. Shen serves as the Technical Program Committee Chair for IEEE Globecom’07, General Co-Chair for Chinacom’07 and QShine’06, the Founding Chair for IEEE Communications Society Technical Committee on P2P Communications and Networking. He also serves as a Founding Area Editor for IEEE Transactions on Wireless Communications; Associate Editor for IEEE Transactions on Vehicular Technology; KICS/IEEE Journal of Communications and Networks; Computer Networks (Elsevier); ACM/Wireless Networks; and Wireless Communications and Mobile Computing (John Wiley), etc. He has also served as Guest Editor for IEEE JSAC, IEEE Wireless Communications, and IEEE Communications Magazine. Dr. Shen received the Excellent Graduate Supervision Award in 2006, and the Outstanding Performance Award in 2004 from the University of Waterloo, the Premier’s Research Excellence Award in 2003 from the Province of Ontario, Canada, and the Distinguished Performance Award in 2002 from the Faculty of Engineering, University of Waterloo. Dr. Shen is a registered Professional Engineer of Ontario, Canada. Alberto Leon-Garcia received the B.S., M.S., and Ph.D. degrees in electrical engineering from the University of Southern California, in 1973, 1974, and 1976 respectively. He is a Full Professor in the Department of Electrical and Computer Engineering, University of Toronto, ON, Canada, and he currently holds the Nortel Institute Chair in Network Architecture and Services. In 1999 he became an IEEE fellow for “For contributions to multiplexing and switching of integrated services traffic”. Dr. Leon-Garcia was Editor for Voice/Data Networks for the IEEE Transactions on Communications from 1983 to 1988 and Editor for the IEEE Information Theory Newsletter from 1982 to 1984. He was Guest Editor of the September 1986 Special Issue on Performance Evaluation of Communications Networks of the IEEE Selected Areas on Communications. He is also author of the textbooks Probability and Random Processes for Electrical Engineering (Reading, MA: Addison-Wesley), and Communication Networks: Fundamental Concepts and Key Architectures (McGraw-Hill), co-authored with Dr. Indra Widjaja.     

Exploiting Mobility for Energy Efficient Data Collection in Wireless Sensor Networks

We analyze an architecture based on mobility to address the problem of energy efficient data collection in a sensor network. Our approach exploits mobile nodes present in the sensor field as forwarding agents. As a mobile node moves in close proximity to sensors, data is transferred to the mobile node for later depositing at the destination. We present an analytical model to understand the key performance metrics such as data transfer, latency to the destination, and power. Parameters for our model include: sensor buffer size, data generation rate, radio characteristics, and mobility patterns of mobile nodes. Through simulation we verify our model and show that our approach can provide substantial savings in energy as compared to the traditional ad-hoc network approach. Sushant Jain is a Ph.D. candidate in the Department of Computer Science and Engineering at the University of Washington. His research interests are in design and analysis of routing algorithms for networking systems. He received a MS in Computer Science from the University of Washington in 2001 and a B.Tech degree in Computer Science from IIT Delhi in 1999. Rahul C. Shah completed the B. Tech (Hons) degree from the Indian Institute of Technology, Kharagpur in 1999 majoring in Electronics and Electrical Communication Engineering. He is currently pursuing his Ph.D. in Electrical Engineering at the University of California, Berkeley. His research interests are in energy-efficient protocol design for wireless sensor/ad hoc networks, design methodology for protocols and next generation cellular networks. Waylon Brunette is a Research Engineer in the Department of Computer Science and Engineering at the University of Washington. His research interests include mobile and ubiquitous computing, wireless sensor networks, and personal area networks. Currently, he is engaged in collaborative work with Intel Research Seattle to develop new uses for embedded devices and RFID technologies in ubiquitous computing. He received a BS in Computer Engineering from the University of Washington in 2002. Gaetano Borriello is a Professor in the Department of Computer Science and Engineering at the University of Washington. His research interests are in embedded and ubiquitous computing, principally new hardware devices that integrate seamlessly into the user’s environment with particular focus on location and identification systems. His principal projects are in creating manageable RFID systems that are sensitive to user privacy concerns and in context-awareness through sensors distributed in the environment as well as carried by users. Sumit Roy received the B. Tech. degree from the Indian Institute of Technology (Kanpur) in 1983, and the M. S. and Ph. D. degrees from the University of California (Santa Barbara), all in Electrical Engineering in 1985 and 1988 respectively, as well as an M. A. in Statistics and Applied Probability in 1988. His previous academic appointments were at the Moore School of Electrical Engineering, University of Pennsylvania, and at the University of Texas, San Antonio. He is presently Prof, of Electrical Engineering, Univ. of Washington where his research interests center around analysis/design of communication systems/networks, with a topical emphasis on next generation mobile/wireless networks. He is currently on academic leave at Intel Wireless Technology Lab working on high speed UWB radios and next generation Wireless LANs. His activities for the IEEE Communications Society includes membership of several technical committees and TPC for conferences, and he serves as an Editor for the IEEE Transactions on Wireless Communications.     

Dropping Rate Reduction in Hybrid WLAN/Cellular Systems by Mobile Ad Hoc Relaying

Future mobile handsets will often be multi-mode, containing both wireless LAN (WLAN) and cellular air interfaces. When such a device is within a WLAN it can be served by the WLAN resources. As it moves out of the WLAN coverage area, it has to be served by the cellular system. Therefore, handoffs are necessary between the WLAN and the cellular system. In loosely coupled WLAN/Cellular systems the system administrator of the WLAN is different from the cellular one. Therefore, in these situations, reducing the dropping probability based on classical methods, such as using some reserved guard channels, is difficult. In this paper, we propose to use ad hoc relaying during the vertical handoff process in a hybrid WLAN/Cellular system. The method that we propose in this paper improves the dropping probability regardless of the number of reserved channels. Therefore, this method could be employed in loosely coupled hybrid systems. Both analytical reasoning and simulation results support the effectiveness of the proposed method. Pejman Khadivi received the BS and MS degrees in computer engineering (Hardware and Computer Systems Architecture) in 1998 and 2000, respectively from Isfahan University of Technology, where he is currently working toward his Ph.D. During the 2003/2004 academic year, he was a Visiting Researcher with the Electrical and Computer Engineering Department, McMaster University, ON, Canada. Different aspects of computer architecture and networking are Mr. Khadivi’s research interests specially, adhoc networks, QoS routing and seamless handoff in hybrid mobile networks. Shadrokh Samavi received the B.S. degrees in industrial technology and electrical engineering from the California State University, Fresno, in 1980 and 1982, respectively, the M.S. degree from the University of Memphis, Memphis, TN, in 1985, and the Ph.D. degree in electrical engineering from Mississippi State University, Mississippi State, in 1989. In 1995, he joined the Electrical and Computer Engineering Department, Isfahan University of Technology, Isfahan, Iran, where he was an Associative Professor. During the 2002/2003 academic year, he was a Visiting Professor with the Electrical and Computer Engineering Department, McMaster University, Hamilton, ON, Canada. His current research interests are implementation and optimization of image-processing algorithms and area-performance tradeoffs in computational circuits. Dr. Samavi is a Registered Professional Engineer (P.E.), USA, and is a member of Eta Kappa Nu, Tau Beta Pi, and the National Association of Industrial Technologists (NAIT). Hossein Saidi received the B.S. and M.S. degrees in electrical engineering (Electronics and communication Eng.) from Isfahan University of Technology (IUT), in 1986 and 1989, respectively, and the Ph.D. degree in electrical engineering from the Washington University in St. Louis, MO. in 1994.From 1994 to 1995, he was a research associates at Washington Univ. St. Louis, and in 1995 he joined the Electrical and Computer Engineering of IUT, where he is an Associate Professor. His Research interest includes ATM, high speed networking, QoS guarantees, routing, algorithms and information theory. Terence D. Todd received the B.A.Sc, M.A.Sc and Ph.D degrees in Electrical Engineering from the University of Waterloo, Waterloo, Ontario, Canada. While at Waterloo he spent 3 years as a Research Associate with the Computer Communications Networks Group (CCNG). He is currently a Professor of Electrical and Computer Engineering at McMaster University in Hamilton, Ontario, Canada.Professor Todd spent 1991 on research leave in the Distributed Systems Research Department at AT&T Bell Laboratories in Murray Hill, NJ. He also spent 1998 on research leave at The Olivetti and Oracle Research Laboratory in Cambridge, England. While at ORL he worked on the piconet project which was an early embedded wireless network testbed.Dr. Todd’s research interests include metropolitan/local area networks, wireless communications and the performance analysis of computer communication networks and systems. He currently holds the NSERC/RIM/CITO Industrial Research Chair on Pico-Cellular Wireless Internet Access Networks. Dr. Todd is a Professional Engineer in the province of Ontario and a member of the IEEE. Dongmei Zhao received the Ph.D degree in Electrical and Computer Engineering from the University of Waterloo, Waterloo, Ontario, Canada in June 2002. Since July 2002 she has been with the Department of Electrical and Computer Engineering, McMaster University, Hamilton, Ontario, Canada where she is an assistant professor. Dr. Zhao’s research interests include modeling and performance analysis, quality-of-service provisioning, access control and admission control in wireless cellular networks and integrated cellular and ad hoc networks. Dr. Zhao is a member of the IEEE.     

MANTIS OS: An Embedded Multithreaded Operating System for Wireless Micro Sensor Platforms

The MANTIS MultimodAl system for NeTworks of In-situ wireless Sensors provides a new multithreaded cross-platform embedded operating system for wireless sensor networks. As sensor networks accommodate increasingly complex tasks such as compression/aggregation and signal processing, preemptive multithreading in the MANTIS sensor OS (MOS) enables micro sensor nodes to natively interleave complex tasks with time-sensitive tasks, thereby mitigating the bounded buffer producer-consumer problem. To achieve memory efficiency, MOS is implemented in a lightweight RAM footprint that fits in less than 500 bytes of memory, including kernel, scheduler, and network stack. To achieve energy efficiency, the MOS power-efficient scheduler sleeps the microcontroller after all active threads have called the MOS sleep() function, reducing current consumption to the μA range. A key MOS design feature is flexibility in the form of cross-platform support and testing across PCs, PDAs, and different micro sensor platforms. Another key MOS design feature is support for remote management of in-situ sensors via dynamic reprogramming and remote login. Shah Bhatti is a Ph.D. student in Computer Science at the University of Colorado at Boulder. He also works as a Senior Program Manager in the R&D Lab for Imaging and Printing Group (IPG) at Hewlett Packard in Boise, Idaho. He has participated as a panelist in workshops on Integrated Architecture for Manufacturing and Component-Based Software Engineering, at IJCAI ‘89 and ICSE ‘98, respectively. Hewlett Packard has filed several patents on his behalf. He received an MSCS and an MBA from the University of Colorado, an MSCE from NTU and a BSCS from Wichita State University. His research interests include power management, operating system design and efficient models for wireless sensor networks. James Carlson is a Ph.D. student in Computer Science at the University of Colorado at Boulder. He received his Bachelor’s degree from Hampshire College in 1997. His research is supported by the BP Visualization Center at CU-Boulder. His research interests include computer graphics, 3D visualization, and sensor-enabled computer-human user interfaces. Hui Dai is a Ph.D. student in Computer Science at the University of Colorado at Boulder. He received his B.E. from the University of Science and Technology, China in 2000, and received has M.S. in Computer Science from the University of Colorado at Boulder in 2002. He has been co-leading the development of the MANTIS OS. His research interests include system design for wireless sensor networks, time synchronization, distributed systems and mobile computing. Jing Deng is a Ph.D. student in Computer Science at the University of Colorado at Boulder. He received his B.E. from Univeristy of Electronic Science and Technology of China in 1993, and his M.E from Institute of Computing Technology, Chinese Academy of Science in 1996. He has published four papers on security wireless sensor networks and is preparing a book chapter on security, privacy, and fault tolerance in sensor networks. His research interests include wireless security, secure network routing, and security for sensor networks. Jeff Rose is an M.S. student in Computer Science at the University of Colorado at Boulder. He received his B.S. in Computer Science from the University of Colorado at Boulder in 2003. He has been co-leading the development of the MANTIS operating system. His research interests include data-driven routing in sensor networks. Anmol Sheth is a Ph.D. student in Computer Science at the University of Colorado at Boulder. He received his B.S. in Computer Science from the University of Pune, India in 2001. His research interests include MAC layer protocol design, energy-efficient wireless communication, and adapting communications to mobility. Brian Shucker is a Ph.D. student in Computer Science at the University of Colorado at Boulder. He received his B.S. in Computer Science from the University of Arizona in 2001, and his M.S. in Computer Science from the University of Colorado at Boulder in December 2003. He has been co-leading the development of the MANTIS operating system. His research interests in wireless sensor networks include operating systems design, communication networking, and robotic sensor networks. Charles Gruenwald is an undergraduate student in Computer Science at the University of Colorado at Boulder. He joined the MANTIS research group in Fall 2003 as an undergraduate researcher. Adam Torgerson is an undergraduate student in Computer Science at the University of Colorado at Boulder. He joined the MANTIS research group in Fall 2003 as an undergraduate researcher. Richard Han joined the Department of Computer Science at the University of Colorado at Boulder in August 2001 as an Assistant Professor, Prof. Han leads the MANTIS wireless sensor networking research project, http://mantis.cs.colorado.edu. He has served on numerous technical program committees for conferences and workshops in the field of wireless sensor networks. He received a National Science Foundation CAREER Award in 2002 and IBM Faculty Awards in 2002 and 2003. He was a Research Staff Member at IBM’s Thomas J. Watson Research Center in Hawthorne, New York from 1997-2001. He received his Ph.D. in Electrical Engineering from the University of California at Berkeley in 1997, and his B.S. in Electrical Engineering with distinction from Stanford University in 1989. His research interests include systems design for sensor networks, secure wireless sensor networks, wireless networking, and sensor-enabled user interfaces.This revised version was published online in August 2005 with a corrected cover date.     

A Development Environment for OSA-Based Applications over the Interworked WLAN and Cellular Networks

In this paper, we propose an OSA-based development environment for interworking WLAN and 3G cellular networks. The main goal of our work is to establish and create an environment that can serve as a demonstration of a working network for OSA-based application developers while featuring mobile services over the interworked LAN and 3G cellular networks. The proposed simulating environment has (i) a location update scheme that is used to obtain mobile users' locations and status information over the interworked WLAN and cellular networks, (ii) an instant message gateway (IMG) simulator that is developed to send and receive generic messages over the interworked WLAN and cellular networks, and (iii) a mapping of Parlay APIs onto SIP signaling messages for multiparty call applications over the interworked WLAN and cellular networks. An illustrated OSA-based application that utilizes the corresponding system functions and modules is developed and verified using the proposed simulating environment. Chung-Ming Huang received the B.S. degree in Electrical Engineering from National Taiwan University on 1984/6, and the M.S. and Ph.D. degrees in Computer and Information Science from The Ohio State University on 1987/12 and 1991/6 respectively. He is currently a professor in Department of Computer Science and Information Engineering, National Cheng Kung University, Taiwan, R.O.C. He is the director of The Promotion Center for Network Applications and Services, Innovative Communication Education Project, Ministry of Education, Taiwan, R.O.C. His research interests include broadband Internet and applications, wireless and mobile network protocols, ubiquitous computing and communications, and multimedia streaming. Tz-Heng Hsu received the B.S. degree from Department of Computer Science and Information Engineering, Feng Chia University on 1996/6, and the M.S. degree and Ph.D from Department of Computer Science and Information Engineering, National Cheng Kung University on 1998/7 and 2005/7, Taiwan, R.O.C. He is currently a assistant professor in Department of Computer Science and Information Engineering, Southern Taiwan University of Technology. His research interests are wireless and mobile network protocols, applications over interworked WLAN and cellular networks and communications, and multimedia streaming. Chih-Wen Chao received the B.S. degree from Department of Engineering Science, National Cheng Kung University on 2003/6, and the M.S. degree from Department of Computer Science and Information Engineering, National Cheng Kung University on 2005/7, Taiwan, R.O.C. His research interests are OSA-based applications and distributed multimedia systems.     

An On-Demand Routing Protocol with Backtracking for Mobile Ad Hoc Networks

A mobile ad hoc network (MANET) is characterized by multi-hop wireless links and frequent node mobility. Communication between non-neighboring nodes requires a multi-hop routing protocol to establish a route. But, the route often breaks due to mobility. The source must rediscover a new route for delivering the data packets. This wastes the resources that are limited in MANET. In this paper, a new on-demand routing protocol is proposed, named on-demand routing protocol with backtracking (ORB), for multi-hop mobile ad hoc networks. We use the multiple routes and cache data technique to reduce the rediscovery times and overhead. After executing the route discovery phase, we find out a set of nodes, named checkpoint, which has the multiple routes to the destination. When a checkpoint node receives a data packet, it caches this data packet in its buffer within a specific time period. When a node detects a broken route during the data packets delivery or receives an error packet, it will either recover the broken route or reply the error packet to the source. If a node can not forward the data packet to the next node, it replies an error packet to the source. This packet is backtracking to search a checkpoint to redeliver the data packet to the destination along other alternate routes. The main advantage of ORB is to reduce the flooding search times, maybe just delay and cost while a route has broken. The experimental results show that the proposed scheme can increase the performance of delivery but reduce the overhead efficiently comparing with that of AODV based routing protocols. Hua-Wen Tsai received the B.S. degree in Information Management from Chang Jung Christian University, Taiwan, in June 1998 and the M.B.A. degree in Business and Operations Management from Chang Jung Christian University, Taiwan, in June 2001. Since September 2001, he has been working towards the Ph.D. degree and currently is a doctoral candidate in the Department of Computer Science and Information Engineering, National Cheng Kung University, Taiwan. His research interests include wireless communication, ad hoc networks, and sensor networks. Tzung-Shi Chen received the B.S. degree in Computer Science and Information Engineering from Tamkang University, Taiwan, in June 1989 and the Ph.D. degree in Computer Science and Information Engineering from National Central University, Taiwan, in June 1994. He joined the faculty of the Department of Information Management, Chung Jung University, Tainan, Taiwan, as an Associate Professor in June 1996. Since November 2002, he has become a Full Professor at the Department of Information Management, Chung Jung University, Tainan, Taiwan. He was a visiting scholar at the Department of Computer Science, University of Illinois at Urbana-Champaign, USA, from June to September 2001. He was the chairman of the Department of Information Management at Chung Jung University from August 2000 to July 2003. Since August 2004, he has become a Full Professor at the Department of Information and Learning Technology, National University of Tainan, Tainan, Taiwan. Currently, he is the chairman of the Department of Information and Learning Technology, National University of Tainan. He co-received the best paper award of 2001 IEEE ICOIN-15. His current research interests include mobile computing and wireless networks, mobile learning, data mining, and pervasive computing. Dr. Chen is a member of the IEEE Computer Society. Chih-Ping Chu received the B.S. degree in agricultural chemistry from National Chung Hsing University, Taiwan, the M.S. degree in computer science from the University of California, Riverside, and the Ph.D. degree in computer science from Louisiana State University. He is currently a Professor in the Department of Computer Science and Information Engineering of National Cheng Kung University, Taiwan. His current research interests include parallel computing, parallel processing, component-based software development, and internet computing.     

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).     

Strategyproof Mechanisms towards Dynamic Topology Formation in Autonomous Networks

In autonomous networks, cooperations among nodes cannot be assumed, since each node is capable of making independent decisions based on their personal preferences. In particular, when a node needs the help of intermediate nodes to relay messages to other nodes, these intermediaries may be reluctant to contribute their network resource for the benefit of others. Ideally, the right amount of incentives should be provided to motivate cooperations among autonomous nodes so that a mutually beneficial network results. In this paper, we leverage the power of mechanism design in microeconomics to design a distributed incentive mechanism that motivates each node towards a more desirable network topology. Since network parameters and constraints change dynamically in reality, the desirable topology can vary over time. Our solution presented in this paper has successfully encompassed such a dynamic nature of the network topology. In addition, we have transformed our solution to an easy-to-implement distributed algorithm, that converges towards the globally optimal topology. Selwyn Yuen obtained his BASc from the University of Waterloo Systems Design Engineering in 2002. He subsequently joined the Department of Electrical and Computer Engineering at the University of Toronto, where he completed his MASc in Computer Engineering in 2004. His Master thesis focuses on applying game theory and mechanism design in peer-to-peer and wireless networks. His other research interests include Artificial Intelligence, Optimization, Network Protocol Design, Distributed Algorithms, Operating Systems, as well as modelling and simulation of the Stock Market. Baochun Li received his B.Engr. degree in 1995 from Department of Computer Science and Technology, Tsinghua University, China, and his M.S. and Ph.D. degrees in 1997 and 2000 from the Department of Computer Science, University of Illinois at Urbana-Champaign. Since 2000, he has been with the Department of Electrical and Computer Engineering at the University of Toronto, where he is currently an Associate Professor and holds the Bell University Laboratories Endowed Chair in Computer Engineering. In 2000, he was the recipient of the IEEE Communications Society Leonard G. Abraham Award in the Field of Communications Systems. His research interests include application-level Quality of Service provisioning, wireless networks, and overlay networks.     

Performance of multiuser network-aware prefetching in heterogeneous wireless systems

We study the performance of multiuser document prefetching in a two-tier heterogeneous wireless system. Mobility-aware prefetching was previously introduced to enhance the experience of a mobile user roaming between heterogeneous wireless access networks. However, an undesirable effect of multiple prefetching users is the potential for system instability due to the racing behavior between the document access delay and the user prefetching quantity. This phenomenon is particularly acute in the heterogeneous environment. We investigate into alleviating the system traffic load through prefetch thresholding, accounting for server queuing prioritization. We propose a novel analysis framework to evaluate the performance of the thresholding approach. Numerical and simulation results show that the proposed analysis is accurate for a wide variety of access, service, and mobility patterns. We further demonstrate that stability can be maintained even under heavy usage, providing both the same scalability as a non-prefetching system and the performance gain associated with prefetching. A preliminary version of this article was presented in the International Conference on Quality of Service in Heterogeneous Wired/Wireless Networks (QShine) 2006. This work was supported in part by the Natural Sciences and Engineering Research Council of Canada and Bell Canada through its Bell University Laboratories R&D program. Ben Liang received honors simultaneous B.Sc. (valedictorian) and M.Sc. degrees in electrical engineering from Polytechnic University in Brooklyn, New York, in 1997 and the Ph.D. degree in electrical engineering with computer science minor from Cornell University in Ithaca, New York, in 2001. In the 2001–2002 academic year, he was a visiting lecturer and post-doctoral research associate at Cornell University. He joined the Department of Electrical and Computer Engineering at the University of Toronto as an Assistant Professor in 2002. His current research interests are in mobile networking and multimedia systems. He received an Intel Foundation Graduate Fellowship in 2000 toward the completion of his Ph.D. dissertation, the Best Paper Award at the IFIP Networking conference in 2005, and the Runner-up Best Paper Award at the International Conference on Quality of Service in Heterogeneous Wired/Wireless Networks in 2006. He is a senior member of IEEE and a member of ACM and Tau Beta Pi. He serves on the organizational and technical committees of a number of major conferences each year. Stephen Drew received his B.A.Sc with honours in Computer Engineering from the University of Waterloo in 2003, and his M.A.Sc in Electrical Engineering at the University of Toronto in 2005 under the supervision of Ben Liang of the Communications group. He is currently employed by General Dynamics Canada, in the engineering research and development team. Da Wang is a third year Electrical Engineering student at the University of Toronto. He has been a recipient of the Adel S. Sedra Outstanding Student Award, the IEEE Canada-Toronto Section Scholarship and the Nortel Institute Undergraduate Scholarship. He held an NSERC award for the summer of 2005.     

Ant-Based Distributed Topology Control Algorithms for Mobile Ad hoc Networks

By adjusting the transmission power of mobile nodes, topology control aims to reduce wireless interference, reduce energy consumption, and increase effective network capacity, subject to connectivity constraints. In this paper, we introduce the Ant-Based Topology Control (ABTC) algorithm that adapts the biological metaphor of Swarm Intelligence to control topology of mobile ad hoc networks. ABTC is a distributed algorithm where each node asynchronously collects local information from nearby nodes, via sending and receiving ant packets, to determine its appropriate transmission power. The operations of ABTC do not require any geographical location, angle-of-arrival, topology, or routing information, and are scalable. In particular, ABTC attempts to minimize the maximum power used by any node in the network, or minimize the total power used by all of the nodes in the network. By adapting swarm intelligence as an adaptive search mechanism, ABTC converges quickly to a good power assignment with respect to minimization objectives, and adapts well to mobility. In addition, ABTC may achieve common power, or properly assign power to nodes with non-uniform distribution. Results from a thorough comparative simulation study demonstrate the effectiveness of ABTC for different mobility speed, various density, and diverse node distributions.This work is supported in part by National Science Foundation under grant ANI-0240398.Chien-Chung Shen received his B.S. and M.S. degrees from National Chiao Tung University, Taiwan, and his Ph.D. degree from UCLA, all in computer science. He was a research scientist at Bellcore Applied Research working on control and management of broadband networks. He is now an assistant professor in the Department of Computer and Information Sciences of the University of Delaware, and a recipient of NSF CAREER Award. His research interests include ad hoc and sensor networks, control and management of broadband networks, distributed object and peer-to-peer computing, and simulation.Zhuochuan Huang received his B.E. degree in Computer Science and Technology from Tsinghua University, P.R. China, in 1998, and his M.S. degree in Computer Science from University of Delaware in 2000. He is currently a PhD candidate with the Department of Computer and Information Sciences at the University of Delaware. His current research interests include the design and simulation of protocols for mobile ad hoc networks.Chaiporn Jaikaeo received his B.Eng degree in computer engineering from Kasetsart University, Thailand, and his M.S. and Ph.D. degrees in computer and information sciences from the University of Delaware in 1996, 1999 and 2004, respectively. He is currently a lecturer in the Department of Computer Engineering at Kasetsart University. His research interests include unicast and multicast routing, topology control, peer-to-peer computing and network management for mobile wireless ad hoc and sensor networks.     

Dynamically anchored conferencing handoff for dual-mode cellular/WLAN handsets

In this paper we consider vertical handoff for enterprise-based dual-mode (DM) cellular/WLAN handsets. When the handset roams out of WLAN coverage, the DM's cellular interface is used to maintain the call by anchoring it through an enterprise PSTN gateway/PBX. Soft handoff can be achieved in this case if the gateway supports basic conference bridging, since a new leg of the call can be established to the conference bridge while the existing media stream path is active. Unfortunately this requires that all intra-enterprise calls be routed through the gateway when the call is established. In this paper we consider a SIP based architecture to perform conferenced dual-mode handoff and propose a much more scalable mechanism for short-delay environments, whereby active calls are handed off into the conference bridge prior to the initiation of the vertical handoff. Results are presented which are taken from a dual-mode handset testbed, from analytic models, and from simulations which characterize the scalability of the proposed mechanism. Mohammed Smadi received the B.Eng and Mgmt and M.A.Sc degrees in Computer Engineering from McMaster University in Hamilton, Ontario, Canada. Mohammed received an NSERC doctoral award in 2005 and is currently a Ph.D. student at the Wireless Networking Group at McMaster University. Terence D. Todd received the B.A.Sc, M.A.Sc and Ph.D. degrees in Electrical Engineering from the University of Waterloo, Waterloo, Ontario, Canada. While at Waterloo he spent 3 years as a Research Associate with the Computer Communications Networks Group (CCNG). He is currently a Professor of Electrical and Computer Engineering at McMaster University in Hamilton, Ontario, Canada. Professor Todd spent 1991 on research leave in the Distributed Systems Research Department at AT&T Bell Laboratories in Murray Hill, NJ. He also spent 1998 on research leave at The Olivetti and Oracle Research Laboratory in Cambridge, England. While at ORL he worked on the piconet project which was an early embedded wireless network testbed. Dr. Todd’s research interests include metropolitan/local area networks, wireless communications and the performance analysis of computer communication networks and systems. He is a past Editor of the IEEE/ACM Transactions on Networking and currently holds the NSERC/RIM/CITO Chair on Pico-Cellular Wireless Internet Access Networks. Dr. Todd is a Professional Engineer in the province of Ontario and a member of the IEEE. Vytas Kezys was born in Hamilton, Canada in 1957. He received the B.Eng. degree in Electrical Engineering from McMaster University, Canada, in 1979. From 1979 to 1998, Mr. Kezys was involved in radar and communications research as Principal Research Engineer at the Communications Research Laboratory, McMaster University. While at McMaster, his research activities included array signal processing for low-angle tracking radar, radar signal processing, and smart antennas for wireless communications. Mr. Kezys was founder and President of TalariCom Inc., a start-up company that developed cost effective smart antenna technologies for broadband wireless access applications. Currently, Mr. Kezys is Director of Advanced Products at Research in Motion in Waterloo, Canada. Vahid S. Azhari received his B.S. and M.S. from the Department of Electrical and Computer Engineering, IUST and University of Tehran, Iran, in 2000 and 2003 respectively. His M.S. research focused on designing scheduling algorithms for switch fabrics. He also worked for two years for the Iranian Telecommunication Research Centre on developing software for SDH switches. He is currently pursuing his Ph.D. degree at the Wireless Networking Laboratory, McMaster University, Canada. His main area of research includes handoff management in integrated wireless networks, WLAN deployment techniques, and wireless mesh networks. Dongmei Zhao received the Ph.D. degree in Electrical and Computer Engineering from the University of Waterloo, Waterloo, Ontario, Canada in June 2002. Since July 2002 she has been with the Department of Electrical and Computer Engineering, McMaster University, Hamilton, Ontario, Canada where she is an assistant professor. Dr. Zhao’s research interests include modeling and performance analysis, quality-of-service provisioning, access control and admission control in wireless cellular networks and integrated cellular and ad hoc networks. Dr. Zhao is a member of the IEEE.     

Non-Cooperative Games for Service Differentiation in CDMA Systems

In this paper, we address the problem of user-class based service differentiation in CDMA networks. Users are categorized into three classes who get differentiated services based on their expected quality of service (QoS) from the service provider and the price they are willing to pay. We adopt a game theoretic approach for allocating resources through a two-step process. During a service admission, resource distribution is determined for each class. Then, the resource allocated to each class is distributed among the active users in that class. We devise a utility function for the providers which considers the expected revenue and the probability of users leaving their service provider if they are not satisfied with the service. Our model demonstrates how power can be controlled in a CDMA network to differentiate the service quality. Also, we show the impact of admitting high paying users on other users. Mainak Chatterjee received his Ph.D. from the department of Computer Science and Engineering at The University of Texas at Arlington in 2002. Prior to that, he completed his B.Sc. with Physics (Hons) from the University of Calcutta in 1994 and M.E. in Electrical Communication Engineering from the Indian Institute of Science, Bangalore, in 1998. He is currently an Assistant Professor in the department of Electrical and Computer Engineering at the University of Central Florida. His research interests include economic issues in wireless networks, applied game theory, resource management and quality-of-service provisioning, ad hoc and sensor networks, CDMA data networking, and link layer protocols. He serves on the executive and technical program committee of several international conferences. Haitao Lin received the BE degree in radio engineering from Southeast University, Nanjing, China, in 1996, the MS degree in computer applications from the Beijing University of Posts and Telecommunications, Beijing, China, in 2000, and Ph.D. in Computer Science and Engineering from The University of Texas at Arlington in 2004. He is currently with Converged Multimedia Services System Engineering at Nortel, Richardson, Texas. His research interests include wireless network performance evaluation and enhancement, wireless link adaptation, wireless network resource management, and applied game theory. Sajal K. Das received B.S. degree in 1983 from Calcutta University, M.S. degree in 1984 from Indian Institute of Science, Bangalore, and Ph.D. degree in 1988 from University of Central Florida, Orlando, all in Computer Science. He is currently a Professor of Computer Science and Engineering and also the Founding Director of the Center for Research in Wireless Mobility and Networking (CReWMaN) at the University of Texas at Arlington (UTA). Prior to 1999, he was a professor of Computer Science at the University of North Texas (UNT), Denton where he founded the Center for Research in Wireless Computing (CReW) in 1997, and also served as the Director of the Center for Research in Parallel and Distributed Computing (CRPDC) during 1995–97. Dr. Das is a recipient of the UNT Student Association's Honor Professor Award in 1991 and 1997 for best teaching and scholarly research; UNT's Developing Scholars Award in 1996 for outstanding research; UTA's Outstanding Faculty Research Award in Computer Science in 2001 and 2003; and the UTA College of Engineering Research Excellence Award in 2003. He is also frequently invited as a keynote speaker at international conferences and symposia. Dr. Das' current research interests include mobile wireless communications, resource and mobility management in wireless networks, mobile and pervasive computing, wireless multimedia, ad hoc and sensor networks, mobile internet architectures and protocols, distributed and grid computing, performance modeling and simulation. He has published over 350 research papers in these areas in international journals and conferences, directed numerous industry and government funded projects, and holds five US patents in wireless mobile networks. He received four Best Paper Awards in the ACM MobiCom'99, ICOIN'01, ACM MSWiM'00, and ACM/IEEE PADS'97. He as the Editor in Chief of the Pervasive and Mobile Computing (PMC) journal and also as an Associate Editor of IEEE Transactions on Mobile Computing, ACM/Kluwer Wireless Networks, Parallel Processing Letters, Journal of Parallel, Distributed and Emerging Systems. He served as General Chair of IEEE WoWMoM'05, PerCom'04, IWDC'04, MASCOTS'02, ACM WoWMoM'00-02; General Vice Chair of IEEE PerCom'03, ACM MobiCom'00 and IEEE HiPC'00-01; Program Chair of IWDC'02, WoWMoM'98-99; TPC Vice Chair of ICPADS'02; and as TPC member of numerous IEEE and ACM conferences. He is Vice Chair of the IEEE Computer Society's TCPP and TCCC Executive Committees.     

SOLONet: Sub-optimal location-aided overlay network for MANETs

Overlay networks have made it easy to implement multicast functionality in MANETs. Their flexibility to adapt to different environments has helped in their steady growth. Overlay multicast trees that are built using location information account for node mobility and have a low latency. However, the performance gains of such trees are offset by the overhead involved in distributing and maintaining precise location information. As the degree of (location) accuracy increases, the performance improves but the overhead required to store and broadcast this information also increases. In this paper, we present SOLONet, a design to build a sub-optimal location aided overlay multicast tree, where location updates of each member node are event based. Unlike several other approaches, SOLONet doesn’t require every packet to carry location information or each node maintain location information of every other node or carrying out expensive location broadcast for each node. Our simulation results indicate that SOLONet is scalable and its sub-optimal tree performs very similar to an overlay tree built by using precise location information. SOLONet strikes a good balance between the advantages of using location information (for building efficient overlay multicast trees) versus the cost of maintaining and distributing location information of every member nodes. Abhishek Patil received his BE degree in Electronics and Telecommunications Engineering from University of Mumbai (India) in 1999 and an MS in Electrical and Computer Engineering from Michigan State University in 2002. He finished his PhD in 2005 from the Department of Computer Science and Engineering at Michigan State University. He is a research engineer at Kiyon, Inc. located in San Diego, California. His research interests include wireless mesh networks, UWB, mobile ad hoc networks, application layer multicast, location-aware computing, RFIDs, and pervasive computing. Yunhao Liu received his BS degree in Automation Department from Tsinghua University, China, in 1995, and an MA degree in Beijing Foreign Studies University, China, in 1997, and an MS and a Ph.D. degree in Computer Science and Engineering at Michigan State University in 2003 and 2004, respectively. He is now an assistant professor in the Department of Computer Science at Hong Kong University of Science and Technology. His research interests include wireless sensor networks, peer-to-peer and grid computing, pervasive computing, and network security. He is a senior member of the IEEE Computer Society. Li Xiao received the BS and MS degrees in computer science from Northwestern Polytechnic University, China, and the PhD degree in computer science from the College of William and Mary in 2002. She is an assistant professor of computer science and engineering at Michigan State University. Her research interests are in the areas of distributed and Internet systems, overlay systems and applications, and sensor networks. She is a member of the ACM, the IEEE, the IEEE Computer Society, and IEEE Women in Engineering. Abdol-Hossein Esfahanian received his B.S. degree in Electrical Engineering and the M.S. degree in Computer, Information, and Control Engineering from the University of Michigan in 1975 and 1977 respectively, and the Ph.D. degree in Computer Science from Northwestern University in 1983. He was an Assistant Professor of Computer Science at Michigan State University from September 1983 to May 1990. Since June 1990, he has been an Associate Professor with the same department, and from August 1994 to May 2004, he was the Graduate Program Director. He was awarded ‘The 1998 Withrow Exceptional Service Award’, and ‘The 2005 Withrow Teaching Excellence Award’. Dr. Esfahanian has published articles in journals such as IEEE Transactions, NETWORKS, Discrete Applied Mathematic, Graph Theory, and Parallel and Distributed Computing. He was an Associate Editor of NETWORKS, from 1996 to 1999. He has been conducting research in applied graph theory, computer communications, and fault-tolerant computing. Lionel M. Ni earned his Ph.D. degree in electrical and computer engineering from Purdue University in 1980. He is Chair Professor and Head of Computer Science and Engineering Department of the Hong Kong University of Science and Technology. His research interests include wireless sensor networks, parallel architectures, distributed systems, high-speed networks, and pervasive computing. A fellow of IEEE, Dr. Ni has chaired many professional conferences and has received a number of awards for authoring outstanding papers.     

On the Use of Multiple Hops in Next Generation Wireless Systems

Traditional cellular networks provide a centralized wireless networking paradigm within the wireless domain with the help of fixed infrastructure nodes such as Base Stations (BSs). On the other hand, Ad hoc wireless networks provide a fully distributed wireless networking scheme with no dependency on fixed infrastructure nodes. Recent studies show that the use of multihop wireless relaying in the presence of infrastructure based nodes improves system capacity of wireless networks. In this paper, we consider three recent wireless network architectures that combine the multihop relaying with infrastructure support – namely Integrated Cellular and Ad hoc Relaying (iCAR) system, Hybrid Wireless Network (HWN) architecture, and Multihop Cellular Networks (MCNs), for a detailed qualitative and quantitative performance evaluation. MCNs use multihop relaying by the Mobile Stations (MSs) controlled by the BS. iCAR uses fixed Ad hoc Relay Stations (ARSs) placed at the boundaries to relay excess traffic from a hot cell to cooler neighbor cells. HWN dynamically switches its mode of operation between a centralized Cellular mode and a distributed Ad hoc mode based on the throughput achieved. An interesting observation derived from these studies is that, none of these architectures is superior to the rest, rather each one performs better in certain conditions. MCN is found to be performing better than the other two architectures in terms of throughput, under normal traffic conditions. At very high node densities, the variable power control employed in HWN architecture is found to be having a superior impact on the throughput. The mobility of relay stations significantly influences the call dropping probability and control overhead of the system and hence at high mobility iCAR which uses fixed ARSs is found to be performing better. This work was supported by Infosys Technologies Ltd., Bangalore, India and the Department of Science and Technology, New Delhi, India. B. S. Manoj received his Ph.D degree in Computer Science and Engineering from the Indian Institute of Technology, Madras, India, in July 2004. He has worked as a Senior Engineer with Banyan Networks Pvt. Ltd., Chennai, India from 1998 to 2000 where his primary responsibility included design and development of protocols for real-time traffic support in data networks. He had been an Infosys doctoral student in the Department of Computer Science and Engineering at the Indian Institute of Technology-Madras, India. He is a recipient of the Indian Science Congress Association Young Scientist Award for the Year 2003. Since the beginning of 2005, he has been a post doctoral researcher in the Department of Electrical and Computer Engineering, University of California, San Diego. His current research interests include ad hoc wireless networks, next generation wireless architectures, and wireless sensor networks. K. Jayanth Kumar obtained his B.Tech degree in Computer Science and Engineering in 2002 from the Indian Institute of Technology, Madras, India. He is currently working towards the Ph.D degree in the department of Computer Science at the University of California, Berkeley. Christo Frank D obtained his B.Tech degree in Computer Science and Engineering in 2002 from the Indian Institute of Technology, Madras, India. He is currently working towards the Ph.D. degree in the department of Computer Science at the University of Illinois at Urbana-Champaign. His current research interests include wireless networks, distributed systems, and operating systems. C. Siva Ram Murthy received the B.Tech. degree in Electronics and Communications Engineering from Regional Engineering College (now National Institute of Technology), Warangal, India, in 1982, the M.Tech. degree in Computer Engineering from the Indian Institute of Technology (IIT), Kharagpur, India, in 1984, and the Ph.D. degree in Computer Science from the Indian Institute of Science, Bangalore, India, in 1988. He joined the Department of Computer Science and Engineering, IIT, Madras, as a Lecturer in September 1988, and became an Assistant Professor in August 1989 and an Associate Professor in May 1995. He has been a Professor with the same department since September 2000. He has held visiting positions at the German National Research Centre for Information Technology (GMD), Bonn, Germany, the University of Stuttgart, Germany, the University of Freiburg, Germany, the Swiss Federal Institute of Technology (EPFL), Switzerland, and the University of Washington, Seattle, USA. He has to his credit over 120 research papers in international journals and over 100 international conference publications. He is the co-author of the textbooks Parallel Computers: Architecture and Programming, (Prentice-Hall of India, New Delhi, India), New Parallel Algorithms for Direct Solution of Linear Equations, (John Wiley & Sons, Inc., New York, USA), Resource Management in Real-time Systems and Networks, (MIT Press, Cambridge, Massachusetts, USA), WDM Optical Networks: Concepts, Design, and Algorithms, (Prentice Hall, Upper Saddle River, New Jersey, USA), and Ad Hoc Wireless Networks: Architectures and Protocols, (Prentice Hall, Upper Saddle River, New Jersey, USA). His research interests include parallel and distributed computing, real-time systems, lightwave networks, and wireless networks. Dr.Murthy is a recipient of the Sheshgiri Kaikini Medal for the Best Ph.D. Thesis from the Indian Institute of Science, the Indian National Science Academy (INSA) Medal for Young Scientists, and Dr. Vikram Sarabhai Research Award for his scientific contributions and achievements in the fields of Electronics, Informatics, Telematics & Automation. He is a co-recipient of Best Paper Awards from the 1st Inter Research Institute Student Seminar (IRISS) in Computer Science, the 5th IEEE International Workshop on Parallel and Distributed Real-Time Systems (WPDRTS), and the 6th and 11th International Conference on High Performance Computing (HiPC). He is a Fellow of the Indian National Academy of Engineering.     

Performance Study of Proactive Flow Handoff for Mobile Ad Hoc Networks

A Mobile Ad hoc Network (MANET) is a collection of wireless mobile computers forming a temporary network without any existing wire line infrastructure. Searching for feasible paths, or routing, is very challenging in mobile ad hoc networks because of frequent topology changes caused by users' mobility. Location information is required by some applications and can be used to facilitate routing implementation. In this paper, we propose a proactive flow handoff method based on nodes' location information. In summary, location information is utilised to reduce the control overhead in route discovery phase, to search quickly for a feasible path upon link breakage, and to hand off a flow to a stable path if the active one breaks based on predication. Keeping “always-on” end-to-end connectivity once a flow is established is the main advantage of this routing method. A thorough simulation study is performed to demonstrate the efficiency of this method. This research was supported by a grant from the Canadian Institute for Telecommunications Research under the NCE program of the Government 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. Janelle Harms received her Ph.D. in Computer Science from the University of Waterloo, Ontario, Canada working in the area of performance analysis of resource allocation mechanisms. She joined the Department of Computing Science at the University of Alberta in 1991 and is currently an Associate Professor there. Her research interests include performance aspects of network resource allocation, routing and design problems.     

Scheduling Sleeping Nodes in High Density Cluster-based Sensor Networks

In order to conserve battery power in very dense sensor networks, some sensor nodes may be put into the sleep state while other sensor nodes remain active for the sensing and communication tasks. In this paper, we study the node sleep scheduling problem in the context of clustered sensor networks. We propose and analyze the Linear Distance-based Scheduling (LDS) technique for sleeping in each cluster. The LDS scheme selects a sensor node to sleep with higher probability when it is farther away from the cluster head. We analyze the energy consumption, the sensing coverage property, and the network lifetime of the proposed LDS scheme. The performance of the LDS scheme is compared with that of the conventional Randomized Scheduling (RS) scheme. It is shown that the LDS scheme yields more energy savings while maintaining a similar sensing coverage as the RS scheme for sensor clusters. Therefore, the LDS scheme results in a longer network lifetime than the RS scheme. Jing Deng received the B.E. and M.E. degrees in Electronic Engineering from Tsinghua University, Beijing, P. R. China, in 1994 and 1997, respectively, and the Ph.D. degree in Electrical and Computer Engineering from Cornell University, Ithaca, NY, in 2002. Dr. Deng is an assistant professor in the Department of Computer Science at the University of New Orleans. From 2002 to 2004, he visited the CASE center and the Department of Electrical Engineering and Computer Science at Syracuse University, Syracuse, NY as a research assistant professor, supported by the Syracuse University Prototypical Research in Information Assurance (SUPRIA) program. He was a teaching assistant from 1998 to 1999 and a research assistant from 1999 to 2002 in the School of Electrical and Computer Engineering at Cornell University. His interests include mobile ad hoc networks, wireless sensor networks, wireless network security, energy efficient wireless networks, and information assurance. Wendi B. Heinzelman is an assistant professor in the Department of Electrical and Computer Engineering at the University of Rochester. She received a B.S. degree in Electrical Engineering from Cornell University in 1995 and M.S. and Ph.D. degrees in Electrical Engineering and Computer Science from MIT in 1997 and 2000 respectively. Her current research interests lie in the areas of wireless communications and networking, mobile computing, and multimedia communication. Dr. Heinzelman received the NSF Career award in 2005 for her work on cross-layer optimizations for wireless sensor networks, and she received the ONR Young Investigator award in 2005 for her research on balancing resource utilization in wireless sensor networks. Dr. Heinzelman was co-chair of the 1st Workshop on Broadband Advanced Sensor Networks (BaseNets '04), and she is a member of Sigma Xi, the IEEE, and the ACM. Yunghsiang S. Han was born in Taipei, Taiwan, on April 24, 1962. He received the B.S. and M.S. degrees in electrical engineering from the National Tsing Hua University, Hsinchu, Taiwan, in 1984 and 1986, respectively, and the Ph.D. degree from the School of Computer and Information Science, Syracuse University, Syracuse, NY, in 1993. From 1986 to 1988 he was a lecturer at Ming-Hsin Engineering College, Hsinchu, Taiwan. He was a teaching assistant from 1989 to 1992 and from 1992 to 1993 a research associate in the School of Computer and Information Science, Syracuse University. From 1993 to 1997 he was an Associate Professor in the Department of Electronic Engineering at Hua Fan College of Humanities and Technology, Taipei Hsien, Taiwan. From 1997 to 2004 he was with the Department of Computer Science and Information Engineering at National Chi Nan University, Nantou, Taiwan. He was promoted to Full Professor in 1998. From June to October 2001 he was a visiting scholar in the Department of Electrical Engineering at University of Hawaii at Manoa, HI, and from September 2002 to January 2004 he was the SUPRIA visiting research scholar in the Department of Electrical Engineering and Computer Science and CASE center at Syracuse University, NY. He is now with the Graduate Institute of Communication Engineering at National Taipei University, Taipei, Taiwan. His research interests are in wireless networks, security, and error-control coding. Dr. Han is a winner of 1994 Syracuse University Doctoral Prize. Pramod K. Varshney was born in Allahabad, India on July 1, 1952. He received the B.S. degree in electrical engineering and computer science (with highest honors), and the M.S. and Ph.D. degrees in electrical engineering from the University of Illinois at Urbana-Champaign in 1972, 1974, and 1976 respectively. Since 1976 he has been with Syracuse University, Syracuse, NY where he is currently a Professor of Electrical Engineering and Computer Science and the Research Director of the New York State Center for Advanced Technology in Computer Applications and Software Engineering. His current research interests are in distributed sensor networks and data fusion, detection and estimation theory, wireless communications, intelligent systems, signal and image processing, and remote sensing he has published extensively. He is the author of Distributed Detection and Data Fusion, published by Springer-Verlag in 1997 and has co-edited two other books. Dr. Varshney is a member of Tau Beta Pi and is the recipient of the 1981 ASEE Dow Outstanding Young Faculty Award. He was elected to the grade of Fellow of the IEEE in 1997 for his contributions in the area of distributed detection and data fusion. In 2000, he received the Third Millennium Medal from the IEEE and Chancellor's Citation for exceptional academic achievement at Syracuse University. He serves as a distinguished lecturer for the AES society of the IEEE. He is on the editorial board Information Fusion. He was the President of International Society of Information Fusion during 2001.