A Reconfigurable Gaussian/Triangular Basis Functions Computation Circuit

A CMOS Gaussian/Triangular Basis functions computation circuit suitable for analog neural networks is proposed. The circuit can be configured to realize any of the two functions. The circuit can approximate these functions with relative root-mean-square error less than 1%. It is shown that the center, width, and peak amplitude of the dc transfer characteristic can be independently controlled. SPICE simulation results using 0.18 μ m CMOS process model parameters of TSMC18 technology are included. Muhammad Taher Abuelma'Atti was born in Cairo, Egypt, in 1942. He received the B.Sc. degree in Electrical Engineering in 1963 from the University of Cairo, Cairo, Egypt, the Ph.D. degree in 1979 and the Doctor of Science degree in 1999 both from the University of Bradford, Bradford, England. From 1963 to 1967, he worked at the Military Technical College in Cairo as a Teaching Assistant. He was with the Iron and Steel Company in Helwan, Cairo, from 1967 to 1973 as a Senior Electrical Engineer. From 1973 to 1976 he was with the College of Engineering, University of Riyadh, Saudi Arabia, as a Teaching Assistant. From 1980 to 1981, he worked with the Faculty of Engineering, University of Khartoum, Sudan, as an Assistant Professor, and from 1981 to 1982 he was with the College of Engineering, King Saud University, Riyadh, Saudi Arabia, as an Assistant Professor. In 1982 he joined the College of Engineering, University of Bahrain and in 1987 he became an Associate Professor. In 1991 he joined the College of Engineering Sciences, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia, where he became a Full Professor in January 1995. Dr. Abuelma'Atti is the recipient of the 1994/1995 Excellence in Teaching Award and the 1995/1996 and 2000/2001 Excellence in Research Award. Both at King Fahd University of Petroleum and Minerals. Dr. Abuelma'Atti is a contributor to Encyclopedia of RF and Microwave Engineering, Kai Chang, Editor, (New York: John Wiley, 2005), Survey of Instrumentation and Measurement, S.A. Dyer, Editor, (New York: John Wiley, 2001), The Encyclopedia of Electrical and Electronic Engineering, J.G. Webster, Editor, (New York:John Wiley, 1999), and Selected Papers on Analog Fiber-Optic Links, E.I. Ackerman, C.H. Cox III and N.A. Riza, Editors, SPIE Milestone Series, (Washington: SPIE Optical Engineering Press, 1998). His research interests include problems related to analysis and design of nonlinear electronic circuits and systems, analog integrated circuits and active networks design. He is the author or co-author of over 500 journal articles and technical presentations. Abdullah Bakri Shwehneh was born in Aleppo Syria, in 1973. He received the B. Sc. degree in electrical engineering in 1998 from Sumy State University, Sumy, Ukraine. In 2001, he received the Postgraduate Diploma in Automatic Control from Aleppo State University, Aleppo, Syria. In 2001, he joined the “Electronic Brain Company for Computer and Electronics” as an Electronic & Computer Engineer and since 2002, he is with King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia, as a Research Assistant. In June 2005 he obtained his Master of Science Degree in Analog Electronics from KFUPM. At present he is a Ph.D. student at KFUPM. His main interests are in Nonlinear circuits, VLSI Analog Design and Neural Networks hardware implementation.     

Introducing consciousness in UWB networks by hybrid modelling of admission control

We formalize a model for a self-organizing network of nodes that operate according to the UWB principle based on hybrid modelling formalism. We design the rules that lead to the formation of the network and in particular an admission control procedure that is capable to handle both continuous and discrete perturbations, while maintaining the network in a condition of stability. Cognition is introduced in the model by allowing nodes to adjust their rules of operation based on the perception of the environment by an elected node, serving as the observer, that is aware of context, evaluates, and selects one strategy of operation. Maria-Gabriella Di Benedetto obtained her Ph.D. in Telecommunications in 1987 from the University of Rome La Sapienza, Italy. In 1991, she joined the Faculty of Engineering of University of Rome La Sapienza, where currently she is a Full Professor of Telecommunications at the Infocom Department. She has held visiting positions at the Massachusetts Institute of Technology, the University of California, Berkeley, and the University of Paris XI, France. In 1994, she received the Mac Kay Professorship award from the University of California, Berkeley. Her research interests include wireless communication systems and speech science. From 1995 to 2000, she directed four European projects for the design of UMTS. Since 2000, she has been active in fostering the development of Ultra Wide Band (UWB) radio communications in Europe. Within the 5th framework, she directed for the Infocom Dept. two European projects (whyless.com and UCAN) aimed at the design and implementation of UWB ad-hoc networks. Currently, within the 6th EU Framework, her “Networking with UWB” research group participates in the PULSERS Integrated Project which will integrate UWB research and development in Europe for the next years, and in the LIAISON Integrated Project as regards the application of UWB to location-based services. She also participates in the HYCON network of excellence. Dr. Di Benedetto has co-edited several Special Issues on UWB communications and networks for several Journals including IEEE JSAC, Journal of Communications and Networks, Mobile Networks and Applications, Eurasip. In 2004, Dr. Di Benedetto co-authored with G. Giancola the first published book on UWB for communications titled “Understanding Ultra Wide Band Radio Fundamentals” and published by Prentice Hall. She recently completed the co-edition of two new books on UWB that will be published by 2005: UWB Communication Systems—A comprehensive overview, with T. Kaiser, D. Porcino, A. Molisch, and I. Oppermann, Hindawi Publishing Corporation, 2005, and Ultra Wideband Wireless Communications with H. Arslan and Z.N. Chen, John Wiley & Sons, Inc., 2005. Maria Domenica Di Benedetto obtained the “Dr. Ing.” degree (summa cum laude) of Electrical Engineering and Computer Science, University of Roma “La Sapienza” in 1976 (Mosè Ascoli Best Student Award). In 1981, she obtained the degree “Docteur-Ingénieur” and in 1987 the degree “Doctorat d’Etat ès Sciences”, Université de Paris-Sud, Orsay, France. From 1979 to 1983, she had been Research Engineer at the scientific centers of IBM in Paris and Rome. From 1983 to 1987, she had been Assistant Professor at the University of Roma “La Sapienza”. From 1987 to 1990, she had been Associate Professor at the Istituto Universitario Navale of Naples. From 1990 to 1993, had been Associate Professor at the University of Roma “La Sapienza”. Since 1994, she has been Professor of Control Theory at University of L’Aquila. From 1995 to 2002, she was Adjunct Professor, Department of EECS, University of California at Berkeley. In 1987, she was Visiting Scientist at MIT; in 1988, 1989 and 1992, Visiting Professor at the University of Michigan, Ann Arbor; in 1992, Chercheur Associé, C.N.R.S., Poste Rouge, Ecole Nationale Supérieure de Mécanique, Nantes, France; in 1990, 1992, 1994 and 1995, McKay Professor at the University of California at Berkeley. Her research interests revolve around nonlinear control and hybrid systems. She was Associate Editor of the IEEE Transactions of Automatic Control and has been Subject Editor of the International Journal of Robust and Nonlinear Control since 1995. Since 2005, she has been a member of the IFAC Technical Committee on Discrete Event and Hybrid Systems. Since 2000, she has been the Director of the Center of Excellence for Research DEWS on “Architectures and Design methodologies for Embedded controllers, Wireless interconnect and System-on-chip”, University of L’Aquila. She is IEEE Fellow and Chairperson of the Standing Committee on Fellow Nominations, IEEE Control Systems Society. Guerino Giancola received the “Laurea” degree (magna cum laude) in Telecommunications Engineering, and the Ph.D. degree in Information and Communication Engineering from University of Rome La Sapienza, in 2001 and 2005, respectively. He is currently a research affiliate at the INFOCOM Department at University of Rome La Sapienza, where is actually holding the course of “Electrical Communications” for the degree on Electronic Engineering. His research interests include the analysis and modelling of Multi User Interference in Impulse Radio systems, and the design of Medium Access Control functions and protocols for UWB ad-hoc networks. Guerino Giancola recently co-authored with Prof. Maria-Gabriella Di Benedetto a book on Ultra Wide Band from radio to the network, titled “Understanding Ultra Wide Band Radio Fundamentals” and published by Prentice Hall in June 2004. He is now involved in the European project “PULSERS—Pervasive Ultra wideband Low Spectral Energy Radio Systems” and in the European Network of Excellence “HYCON—Hybrid Control: Taming Heterogeneity and Complexity of Networked Embedded Systems”. Guerino Giancola is a member of the IEEE Communication Society.     

Design of Current-Mode Square-Root Domain Band-Pass Filter with Reduced Voltage

A design technique for current-mode square-root domain band-pass filter fabricated in a 0.25 μ m CMOS process is presented. The basic building block consists of current-mode current mirrors, square-root circuits and capacitors, and in which the overall supply voltage is reduced by adopting low-voltage level-shift current mirror. Both of the simulation and measured results, which are in good agreement, indicate that the prototype of the band-pass provides tunable center frequency of 4–10 MHz with bias-current-tunable, −26.7 dB total harmonic distortion (THD), and approximately 1.598 mW power dissipation with a 1.5 V supply voltage. Advantages of the proposed filter include high frequency operation, tuneability, low supply voltage operation, low power consumption, and low third order intermodulation distortion. Gwo-Jeng Yu was born in Kaohsiung, Taiwan, R.O.C., in 1954. He received the B.S. and M.S. degrees in the Department Electronic Engineering in 1972 and 1976, respectively, from National Chiao Tung University, HsinChu, Taiwan, R.O.C., and he is currently working toward the Ph.D. degree in the Department of Electrical Engineering of National Cheng Kung University, Tainan, Taiwan, R.O.C. Since 1978, he has been on the Faculty of Institute of Cheng Shiu Technology, Kaohsiung, Taiwan, R.O.C., where he is currently a Associate Professor in the Department of Electronic Engineering. During 1979–1990, he was the Chairman of the Electronic Engineering Department and the Chairman of the Microelectronics and Information Technology Center during 1996–2000. His current researches include current-mode circuits design, analog IC design and VLSI circuit design. Chun-Yueh Huang was born in Taichung, Taiwan, Republic of China, on March 24, 1967. He received the B.S. degree in industrial education from the National Chang Hwa Normal University, Chang Hwa, Taiwan in 1991, M.S. and Ph.D. degrees both in electrical engineering from the National Cheng Kung University, Tainan, Taiwan, in 1993 and 1997, respectively. Since 1999 he has been with the Kan Shan University of Technology, where he is currently Associate Professor and Chairman of the Department of Electronic Engineering. His current researches include current-mode circuits design, VLSI design, analog IC design, and analog IP design. Jenn-Jiun Chen received the B.S. and M.S. degrees both in electrical engineering from the National Cheng Kung University, Tainan, Taiwan, in 2001 and 2003, respectively. His research interests are design and modeling of current mode circuit, low power analog circuit design, current mode filters, and instrumental amplifier in micro sensor applications. He received Chip Design Award from the Chip Implementation Center, National Applied Research Laboratories, in 2002. Bin-Da Liu received the B.S., M.S., and Ph.D. degrees all in electrical engineering from the National Cheng Kung University, Tainan, Taiwan, in 1973, 1975, and 1983, respectively. Since 1977 he has been on the faculty of the National Cheng Kung University, where he is currently Distinguished Professor in the Department of Electrical Engineering and Director of the SoC Research Center. During 1983–1984, he was a Visiting Assistant Professor in the Department of Computer Science, University of Illinois at Urbana-Champaign. During 1988–1992, he was the Director of Electrical Laboratories, National Cheng Kung University. He was the Associate Chair of the Electrical Engineering Department during 1996–1999 and the Chair during 1999–2002. Since 1995 he has been a consultant of the Chip Implementation Center, National Applied Research Laboratories. He has published more than 190 technical papers. He also contributed chapters in the book Neural Networks and Systolic Array Design (D. Zhang Ed. Singapore: World Scientific Publisher, 2002) and the book Accuracy Improvements in Linguistic Fuzzy Modeling (J. Casillas, O. Cordn, F. Herrera, and L. Magdalena Eds. Heidelberg, Germany: Springer-Verlag, 2003). He is currently a CAS Associate Editor of the IEEE Circuits & Devices Magazine and an Associate Editor of the IEEE Transactions on Circuits and Systems-I. His current research interests include low power circuit design, SoC system integration and verification, and VLSI implementation for fuzzy-neural networks and audio/video signal processors.     

Fluid coding and coexistence in ultra wide band networks

Time Hopping Ultra Wide Band (TH–UWB) commonly encodes the data symbols by shifting the position of the transmitted pulses by a quantity that is quantized over the inter-pulse interval range. In this paper, we relax the hypothesis of a discrete value for the time shift introduced by the TH code, by considering the possibility of generating real-valued codes that introduce time hopping in a “fluid” way. The effect on the power spectral density of generated signals is analyzed, and application of fluid coding to multiple access and to network coexistence is investigated by simulation. Portions of this work were presented at the 2005 2nd International Workshop Networking with Ultra Wide Band, Workshop on Ultra Wide Band for Sensor Networks [M.G. Di Benedetto, G. Giancola, D. Domenicali and P. Ingargiola “Fluid Coding in Time Hopping Ultra Wide Band Networks,” Proceedings of the IEEE 2nd International Workshop Networking with Ultra Wide Band—Ultra Wide Band for Sensor Networks, July 2005, Rome, Italy]. Daniele Domenicali took his Laurea degree in Telecommunications Engineering at the University of Rome La Sapienza in 2004. In November 2004 Domenicali wins the open competition for PhD scholarship in Information and Communication Engineering. He is teaching assistant for the course of “UWB Communication Systems” conducted by Professor Maria Gabriella Di Benedetto at the University of Rome La Sapienza. His research activity includes Pulse Shaping and the related modulation and coding techniques (Time Hopping Coding, PAM and PPM Modulation). Particular attention is paid to the effects produced in the Power Spectral Density, in order to find solutions capable of optimizing spectrum occupation while meeting the constraints imposed by emission masks. Daniele Domenicali is involved in the European Network of Excellence HYCON (Hybrid Control: Taming Heterogeneity and Complexity of Networked Embedded Systems). Guerino Giancola received the “Laurea” degree (magna cum laude) in Telecommunications Engineering, and the Ph.D. degree in Information and Communication Engineering from University of Rome La Sapienza, in 2001 and 2005, respectively. He is currently a research affiliate at the INFOCOM Department at University of Rome La Sapienza, where is actually holding the course of “Electrical Communications” for the degree on Electronic Engineering. His research interests include the analysis and modelling of Multi User Interference in Impulse Radio systems, and the design of Medium Access Control functions and protocols for UWB ad-hoc networks. Guerino Giancola recently co-authored with Prof. Maria-Gabriella Di Benedetto a book on Ultra Wide Band from radio to the network, titled “Understanding Ultra Wide Band Radio Fundamentals” and published by Prentice Hall in June 2004. He is now involved in the European project “PULSERS – Pervasive Ultra wideband Low Spectral Energy Radio Systems” and in the European Network of Excellence “HYCON- Hybrid Control: Taming Heterogeneity and Complexity of Networked Embedded Systems”. Guerino Giancola is a member of the IEEE Communication Society. Maria-Gabriella Di Benedetto obtained her Ph.D. in Telecommunications in 1987 from the University of Rome La Sapienza, Italy. In 1991, she joined the Faculty of Engineering of University of Rome La Sapienza, where currently she is a Full Professor of Telecommunications at the Infocom Department. She has held visiting positions at the Massachusetts Institute of Technology, the University of California, Berkeley, and the University of Paris XI, France. In 1994, she received the Mac Kay Professorship award from the University of California, Berkeley. Her research interests include wireless communication systems and speech science. From 1995 to 2000, she directed four European projects for the design of UMTS. Since 2000, she has been active in fostering the development of Ultra Wide Band (UWB) radio communications in Europe. Within the 5th framework, she directed for the Infocom Dept. two European projects (whyless.com and UCAN) aimed at the design and implementation of UWB ad-hoc networks. Currently, within the 6th EU Framework, her “Networking with UWB” research group participates in the PULSERS Integrated Project which will integrate UWB research and development in Europe for the next years, and in the LIAISON Integrated Project as regards the application of UWB to location-based services. She also participates in the HYCON network of excellence. Dr. Di Benedetto is co-edited several Special Issues on UWB communications and networks for several Journals including IEEE JSAC, Journal of Communications and Networks, Mobile Networks and Applications, Eurasip. In 2004, Dr. Di Benedetto co-authored with G. Giancola the first published book on UWB for communications titled “Understanding Ultra Wide Band Radio Fundamentals” and published by Prentice Hall. She recently completed the co-edition of two new books on UWB that will be published by 2005: UWB Communication Systems - A comprehensive overview, with T. Kaiser, D. Porcino, A. Molisch, and I. Oppermann, Hindawi Publishing Corporation, 2005, andUltra Wideband Wireless Communications with H. Arslan and Z.N. Chen, John Wiley & Sons, Inc., 2005.     

Blind Stochastic Feature Transformation for Channel Robust Speaker Verification

To improve the reliability of telephone-based speaker verification systems, channel compensation is indispensable. However, it is also important to ensure that the channel compensation algorithms in these systems surpress channel variations and enhance interspeaker distinction. This paper addresses this problem by a blind feature-based transformation approach in which the transformation parameters are determined online without any a priori knowledge of channel characteristics. Specifically, a composite statistical model formed by the fusion of a speaker model and a background model is used to represent the characteristics of enrollment speech. Based on the difference between the claimant's speech and the composite model, a stochastic matching type of approach is proposed to transform the claimant's speech to a region close to the enrollment speech. Therefore, the algorithm can estimate the transformation online without the necessity of detecting the handset types. Experimental results based on the 2001 NIST evaluation set show that the proposed transformation approach achieves significant improvement in both equal error rate and minimum detection cost as compared to cepstral mean subtraction and Znorm. Kwok-Kwong Yiu received a BEng (Hons) degree in 1992 and an MPhil degree in 2000 from the Department of Electronic and Information Engineering, The Hong Kong Polytechnic University. He was a Research Associate at the same institute from 2000 to 2001. He is currently a PhD student and his supervisor is Dr. M.W. Mak. His research interests include speaker verification, neural networks, and channel compensation. Man-Wai Makreceived a BEng (Hons) degree in Electronic Engineering from Newcastle Upon Tyne Polytechnic in 1989 and a PhD degree in Electronic Engineering from the University of Northumbria at Newcastle in 1993. He was a Research Assistant at the University of Northmubria at Newcastle, from 1990 to 1993. He joined the Department of Electronic Engineering at the Hong Kong Polytechnic University as a Lecturer in 1993 and as an Assistant Professor in 1995. Since 1995, Dr. Mak has been an executive committee member of the IEEE Hong Kong Section Computer Chapter. He is currently the chairman of the IEEE Hong Kong Section Computer Chapter. Dr. Mak's research interests include speaker recognition and neural networks. Ming-Cheung Cheung received a BSc (Hons) degree in Information Technology from The Hong Kong Polytechnic University in 2002. Since November 2002, he has been an MPhil student at the Department of Electronic and Information Engineering of The Hong Kong Polytechnic University. His research interests include pattern recognition, neural networks, and fusion techniques for multimodal biometric authentication. Sun-Yuan Kung received his Ph.D. Degree in Electrical Engineering from Stanford University. In 1974, he was an Associate Engineer of Amdahl Corporation, Sunnyvale, CA. From 1977 to 1987, he was a Professor of Electrical Engineering-Systems, the University of Southern California. Since 1987, he has been a Professor of Electrical Engineering, Princeton University. Since 1990, he has served as an Editor-In-Chief of Journal of VLSI Signal Processing Systems. He served as a founding member and General Chairman of various international conferences, including IEEE Workshops on VLSI Signal Processing in 1982 and 1986 (L.A.), International Conference on Application Specific Array Processors in 1990 (Princeton) and 1991 (Barcelona), and IEEE Workshops on Neural Networks and Signal Processing in 1991 (Princeton), 1992 (Copenhagen) and 1998 (Cambridge, UK), the First IEEE Workshops on Multimedia Signal Processing in 1997 (Princeton), and International Computer Symposium in 1998 (Tainan).Dr. Kung is a Fellow of IEEE. He was the recipient of 1992 IEEE Signal Processing Society's Technical Achievement Award for his contributions on “parallel processing and neural network algorithms for signal processing”. He was appointed as an IEEE-SP Distinguished Lecturer in 1994. He received 1996 IEEE Signal Processing Society's Best Paper Award. He was a recipient of the IEEE Third Millennium Medal in 2000. He has authored more than 300 technical publications, including three books “VLSI Array Processors”, (Prentice Hall, 1988) (with Russian and Chinese translations), “Digital Neural Networks”, Prentice Hall, 1993, and “Principal Component Neural Networks”, John Wiley, 1996.     

New Paradigms in Wireless Communication Systems

This paper discusses what a new paradigm can be in wireless communication systems of the twenty-first century. First, it suggests two directions for the new paradigm; one is “micro- and nano-device communication system” which is the projected scenario considering that the entities in source and destination have been shrinking throughout the history of wireless communication systems. The second direction is “networked robot system”, which emerges as a natural extension of mobile ad hoc networking where the networking is closely related to motion control of robots. Secondly, it shows two interesting research topics, “the new communication protocol design” and “signal processing”, respectively, that arise in the wake of the fusion between the two directions in the novel communication paradigm. Finally, it considers a new science of wireless communications in the twenty-first century. Shinsuke Hara received the B.Eng., M.Eng. and Ph.D. degrees in communications engineering from Osaka University, Osaka, Japan, in 1985, 1987 and 1990, respectively. From April 1990 to March 1997, he was an assistant professor in the Department of Communication Engineering, School of Engineering, Osaka University, and from October 1997 to September 2005, he was an associate professor in the Department of Electronic, Information and Energy Engineering, Graduate School of Engineering, Osaka University. Since October 2005, he has been a professor in the Department of Physical Electronics and Informatics, Graduate School of Engineering, Osaka City University. In addition, from April 1995 to March 1996, he was a visiting scientist at Telecommunications and Traffic Control Systems Group, Delft University of Technology, Delft, The Netherlands. His research interests include wireless communications systems and digital signal processing. Hiroyuki Yomo received B.S. degree in communication engineering from Department of Communication Engineering, Osaka University, Osaka, Japan, in 1997, and M.S. and Ph.D. degrees in communication engineering from Department of Electronic, Information, and Energy Engineering, Graduate School of Engineering, Osaka University, Osaka Japan, in 1999 and 2002, respectively. From April 2002 to March 2004, he was a Post-doctoral Fellow in Department of Communication Technology, Aalborg University, Denmark. From April 2004 to September 2004, he was at Internet System Laboratory, NEC Corporation, Japan. Since October 2004, he has been an Assistant Research Professor in Center for TeleInfrastructure (CTIF), Aalborg University, Denmark. His main research interests are access technologies, radio resource management, and link-layer techniques in the area of short-range communication, cellular network, cognitive radio, and sensor network. Petar Popovski received the Dipl.-Ing. in electrical engineering and M.Sc. in communication engineering from the Faculty of Electrical Engineering, Sts. Cyril and Methodius University, Skopje, Republic of Macedonia, in 1997 and 2000, respectively. He received a Ph.D. degree from Aalborg University, Denmark, in 2004. From 1998 to 2001 he was a teaching and research assistant at the Institute of Telecommunications, Faculty of Electrical Engineering in Skopje. He is currently Assistant Professor at the Department of Communication Technology at the Aalborg University. His research interests are related to the PHY-MAC aspects of wireless protocols, wireless sensor networks, random access protocols, and network coding. Kazunori Hayashi received the B.E., M.E. and Ph.D. degrees in communication engineering from Osaka University, Osaka, Japan, in 1997, 1999 and 2002, respectively. He spent 3 months in 2000 at Aalborg University, Denmark, as a Visiting Scholar. Since 2002, he has been with the Department of Systems Science, Graduate School of Informatics, Kyoto University. He is currently an Assistant Professor there. His research interests include digital signal processing for communications systems.     

Layout preferences concerning matching in a fully differential ΔΣ modulator design

A fully differential architecture has numerous advantages in a switched-capacitor delta-sigma modulator such as immunization to clock-induced noise, supply rejection, simple sign conversion of integrator gain and doubled output dynamic range. Efficient use of the fully differential architecture nevertheless requires a completely symmetrical layout and routing, which may contradict with the requirements of component matching. Some design choices have to be made at this point, depending on what requirements can be compromised. This paper discusses the importance of certain layout features which may serve as a guide in making these design choices. Hakan Binici was born in Istanbul, Turkey, in 1969. He received his B.Sc. and M.Sc. degrees respectively from Istanbul Technical University and the Bogazici University in Istanbul in 1989 and 1995. Since 1997 he has been working as a research scientist at the Electronics Laboratory of the University of Oulu in Finland. He is currently continuing his research towards a Ph.D. His research interests focus on low-voltage, low-power analog VLSI systems and ΔΣ modulators. Juha Kostamovaara received the degrees of Dipl. Eng, Licentiate of Tech. and Doctor of Tech. in electrical engineering in 1980, 1982 and 1987, respectively, all from the University of Oulu, Finland. He was Acting Associate Professor of Electronics in the Department of Electrical Engineering at the University of Oulu in 1987–1993, and was nominated Associate Professor from the beginning of 1993. During 1994 he worked as an Alexander von Humboldt Scholar at the Technical University of Darmstadt, Germany. In 1995 he was invited to become full Professor of Electronics at the University of Oulu, where he is currently also head of the Electronics Laboratory. Prof. Kostamovaara's main interest is in the development of high-speed electronic circuits and systems and their applications in electronic and optoelectronic measurements and radio mobile telecommunications. An erratum to this article can be found at     

Programmable SC Biquad Using One Single Capacitor Bank

This paper presents a new technique for programming SC circuits using a single time-multiplexed capacitor bank, achieving a significant reduction in capacitance area. Simulation and experimental results obtained with a programmable biquad low pass filter show the validity of the proposed method.Antonio Torralba was born in Seville, Spain. He received the electrical engineering and Ph.D. degrees from the University of Seville, Seville, Spain, in 1983 and 1985, respectively. Since 1983, he has been with the Department of Electronic Engineering, School of Engineering, University of Seville, where he has been an Assistant professor, Associate Professor (1987), and Professor (1996). He has published 30 papers in journals and more than 80 papers in conferences. His research interests are in the design and modeling of low-voltage analog circuits, analog and mixed-signal design, analog to digital conversion, and electronic circuits and systems with application to control and communication.Alfredo Pérez Vega-Leal was born in Seville, Spain. He received the Electrical Engineering and Ph.D. degrees from the University of Seville, Seville, Spain, in 1998 and 2003, respectively. Since 1995, he has been with the Department of Electronic Engineering, School of Engineering, University of Seville, as research student and became an Associate Professor in 1999. His research interests are related to low-voltage low-power analog circuit design, A/D and D/A conversion.Ramón González Carvajal was born in Seville, Spain. He received the Electrical Engineering and Ph.D. degrees from the University of Seville, Seville, Spain, in 1995 and 1999, respectively. Since 1996, he has been with the Department of Electronic Engineering, School of Engineering, University of Seville, where he has been an Associate Professor (1996), and Professor (2002). He has published more than 100 papers in International Journals and Conferences. His research interests are related to low-voltage low-power analog circuit design, A/D and D/A conversion, and analog and mixed signal processing.     

A Comparative Evaluation of Designs for Reliable Memory Systems

This paper addresses the design of storage systems for operation under critical environmental conditions. For these applications, these systems should have low latency time in access, high performance in throughput and high storage capabilities; therefore, they must be assembled using highly reliable components, while allowing flexibility in design. Commercial Off The Shelf (COTS) components have often been used. A COTS-based architecture is analyzed in this paper; the proposed architecture uses design-level techniques (such as error detection/correction codes and scrubbing) to make commercially available Dynamic Random Access Memory (DRAM) chips tolerant to faults. This paper provides a complete and novel analysis of engineering alternatives which arise in the design of a highly reliable memory system based on Reed Solomon coding. A comparative analysis of methods for permanent fault detection is provided; moreover using a Markovian characterization, different functional arrangements (based on code and scrubbing frequency) are investigated and evaluated.Gian Carlo Cardarilli received the Laurea (summa cum laude) in 1981 from the University of Rome La Sapienza. He works for the University of Rome Tor Vergata since 1984. At present he is full professor of Digital Electronics and Electronics for Communication Systems at the University of Rome Tor Vergata. During the years 1992–1994 he worked for the University of L Aquila. During the years 1987/1988 he worked for the Circuits and Systems team at EPFL of Lausanne (Switzerland). Professor Cardarilli interests is in the area of VLSI architectures for Signal Processing and IC design. In this field he published over 140 papers in international journals and conferences. He also participated to the work group of JESSI-SMI for the support to the medium and small industries. For this structure he consulted different SMIs, designing a number ASICs, in order to introduce the microelectronics technology in the industry’s products. He has also regular cooperation with companies like Alenia Aerospazio, Rome, Italy, STM, Agrate Brianza, Italy, Micron, Avezzano, Italy, Ericsson Lab, Rome, Italy and with a lot of SMEs. Scientific interests of Professor Cardarilli concern the design of special architectures for signal processing. In particular, he works in the field of computer arithmetic and its application to the design of fast signal digital processor. He also developed mixed-signal neural network architectures implementing them in silicon technology. Recently, he also proposed different new solutions for the implementation of fault-tolerant architectures.Fabrizio Lombardi graduated in 1977 from the University of Essex (UK) with a B.Sc. (Hons.) in Electronic Engineering. In 1977 he joined the Microwave Research Unit at University College London, where he received the Master in Microwaves and Modern Optics (1978), the Diploma in Microwave Engineering (1978) and the Ph.D. from the University of London in 1982.He is currently the holder of the International Test Conference (ITC) Endowed Professorship at Northeastern University, Boston. At the same Institution during the period 1998–2004 he served as Chair of the Department of Electrical and Computer Engineering. Prior to Northeastern University he was a faculty member at Texas Tech University, the University of Colorado-Boulder and Texas A&M University.Dr. Lombardi has received many professional awards: the Visiting Fellowship at the British Columbia Advanced System Institute, University of Victoria, Canada (1988), twice the Texas Experimental Engineering Station Research Fellowship (1991–1992, 1997–1998) the Halliburton Professorship (1995), the Outstanding Engineering Research award at Northeastern University (2004) and an International Research award from the Ministry of Science and Education of Japan (1993–1999). Dr. Lombardi was the recipient of the 1985/86 Research Initiation award from the IEEE/Engineering Foundation and a Silver Quill award from Motorola-Austin (1996).Dr. Lombardi was an Associate Editor (1996–2000) of IEEE Transactions on Computers and a Distinguished Visitor of the IEEE-CS (1990–1993 and 2001–2004). Since 2000, he has been the Associate Editor-In-Chief of IEEE Transactions on Computers and an Associate Editor of the IEEE Design and Test Magazine. Since 2004 he serves as the Chair of the Committee on “Nanotechnology Devices and Systems” of the Test Technology Technical Council of the IEEE.Dr. Lombardi has been involved in organizing many international symposia, conferences and workshops sponsored by professional organizations as well as guest editor of Special Issues in archival journals and magazines such as the IEEE Transactions on Computers, IEEE Transactions on Instrumentation and Measurement, the IEEE Micro Magazine and the IEEE Design & Test Magazine. He is the Founding General Chair of the IEEE Symposium on Network Computing and Applications.His research interests are testing and design of digital systems, quantum and nano computing, ATE systems, configurable/network computing, defect tolerance and CAD VLSI. He has extensively published in these areas and edited six books.Marco Ottavi is currently postdoctoral research associate at the ECE Department of Northeastern University in Boston. He received the Laurea degree in Electronic Engineering from University of Rome “La Sapienza” in 1999 and the Ph.D. in Microelectronics and Telecommunications from University of Rome “Tor Vergata” in 2004. In 2000 he was with ULISSE Consortium, Rome as designer of digital systems for space applications. In 2003 he was visiting research assistant at ECE Department of Northeastern University. His research interests include yield and reliability modeling, fault-tolerant architectures, on-line testing and design of nano scale circuits and systems.Salvatore Pontarelli is currently postdoctoral research associate at the University of Rome, Tor Vergata. He received the Laurea degree in Electronic Engineering from the University of Bologna in 1999 and the Ph.D. in Microelectronics and Telecommunications Engineering from the University of Rome Tor Vergata in 2003. His research mainly focuses on fault tolerance, on-line testing and reconfigurable digital architectures.Adelio Salsano was born in Rome on December 26, 1941 and is currently full professor of Microelectronics at the University of Rome, Tor Vergata where he teaches the courses of Microelectronics and Electronic Programmable Systems. His present research work focuses on the techniques for the design of VLSI circuits, considering both the CAD problems and the architectures for ASIC design. In particular, of relevant interest are the research activities on fault tolerant/fail safe systems for critical environments as space, automotive etc.; on low power systems considering the circuit and architectural points of view; and on fuzzy and neural systems for pattern recognition. An international patent and more than 90 papers on international journals or presented in international meetings are the results of his research activity. At present he is the President of a national consortium named U.L.I.S.S.E., between ten universities, three polytechnics and several of the biggest national industries, as STMicroelectronics, ESAOTE, FINMECCANICA. He is responsible for contracts with the ASI, Italian Space Agency, for the evaluation and use in space environment of COTS circuits and for the definition of new suitable architectures for space applications. Professor Salsano is also involved in professional activities in the field of information technology and is also consultant of many public authorities for specific problems. In particular, he is consultant of the Departments of the Research and of the Industry, of IMI and of other authorities for the evaluation of industrial public and private research projects. Professor Salsano was a member of the consulting Committee for Engineering Sciences of the CNR (National Research Council) from 1981 to 1994 and participated in the design of public research programs in the fields of Telematics, Telemedicine, Office Automation, Telecommunication and, recently, Microelectronics and Bioelectronics.     

Input-Matching and Offset-Cancelling Networks for Limiting Amplifiers in Optical Communication Systems

The diffusion of optical communication systems in the access network and for short-haul datacom applications requires the use of low-cost plastic packages: the functional block most affected is the limiting amplifier, that is often the first stage of the Clock and Data Recovery (CDR) IC. In this paper we illustrate the design issues of the input-matching and offset-cancelling network for a differential limiting amplifier for optical communication systems, with particular emphasis on the effect of bond wires. We discuss the limitations of passive feedback networks when used both for offset suppression and for input matching, and propose a topology that overcomes such limitations by using an active feedback loop. A 50 Ω-loaded differential pair is used to achieve input matching and high offset suppression, and its buffering action desensitizes the input matching from the effect of the bond wires connecting off-chip filtering capacitors. Very good performance even with low cost plastic packages can be achieved by solving the trade-off between power consumption, offset suppression and the value of the low-pass filtering capacitors. Design examples of CDR IC's for 2.5 Gb/s optical systems are presented to compare the proposed topology with solutions based on passive feedback networks. Marco Balsi received the laurea (M.Sc.) degree in 1991 and the dottorato di ricerca (Ph.D.) in 1995 in Electronic Engineering from University of Roma “La Sapienza”, Roma, Italy. Since 1996 he is with “La Sapienza” University as ricercatore (assistant professor). He is engaged in research in nonlinear and soft-computing-based signal processing (especially for biomedical imaging), artificial vision, mechatronics, and anti-personnel mine detection. He has published about 60 paper in international journals and refereed conferences. Francesco Centurelli received the laurea degree (cum laude) and the Ph.D. degree in electronic engineering from the University of Roma “La Sapienza”, Roma, Italy, in 1995 and 2000, respectively. He is currently doing postdoctoral work with the Electronic Engineering Department of the University of Roma “La Sapienza.” His research interests include system-level analysis and design of clock recovery circuits and high-speed analog integrated circuits, with particular emphasis on gigabit-rate optical communication systems. Andrea Pallotta received the M.S. degree in electronic engineering from the University of Ancona, Ancona, Italy. From 1991 to 1999, he was with Italtel, Italy, where he joined several European Community research projects in the field of SDH and WDM fiber-optic transmission systems for both transport and access networks. From 1999 to 2000, he was with Siemens Information and Communication Networks, where he was responsible for the SDH Cross-Connect advanced development group. In September 2000, he joined the STMicroelectronics Company, where he is currently responsible for the electrooptical interface design group. His research interests include GaAs and silicon high-speed ICs, active optical devices, high-speed TX and RX optical modules, and fiber-optic transmission system engineering. Alessandro Trifiletti was born in Roma, Italy, in 1959. In 1991, he joined the Electronic Engineering Department of the University of Roma “La Sapienza” as a Research Assistant and is currently an Assistant Professor. His research interests include high-speed circuit design techniques and III-V device modeling.     

Design of Square-Root Domain Filters

In this paper, a square-root domain band-pass filter and biquad filter which are based on the MOSFET square law are proposed. Both of the square-root domain filters operated at 2.5 V supply voltage are constituted by current mirrors, current-mode square-root circuits and capacitors. The circuits presented have been simulated and fabricated using 0.25 m CMOS process. Both of simulation and measured results which are in good agreement indicate that the center frequency f₀ is not only attainable at megahertz frequencies but also tunable electronically. The proposed circuits have the merits of high frequency operation, tuneability, low power supply voltage operation, low third order intermodulation distortion and low total harmonic distortion.Gwo-Jeng Yu was born in Kaohsiung, Taiwan, R.O.C., in 1954. He received the B.S. and M.S. degrees in the Department Electronic Engineering in 1972 and 1976, respectively, from National Chiao Tung University, HsinChu, Taiwan, R.O.C., and he is currently working toward the Ph.D. degree in the Department of Electrical Engineering of National Cheng Kung University, Tainan, Taiwan, R.O.C.Since 1978, he has been on the Faculty of Institute of Cheng Shiu Technology, Kaohsiung, Taiwan, R.O.C., where he is currently a Associate Professor in the Department of Electronic Engineering. During 1979–1990, he was the Chairman of the Electronic Engineering Department and the Chairman of the Microelectronics and Information Technology Center during 1996–2000.His current researches include current-mode circuits design, analog IC design and VLSI circuit design.Chun-Yueh Huang was born in Taichung, Taiwan, Republic of China, on March 24, 1967. He received the B.S. degree in industrial education from the National Chang Hwa Normal University, Chang Hwa, Taiwan in 1991, M.S. and Ph.D. degrees both in electrical engineering from the National Cheng Kung University, Tainan, Taiwan, in 1993 and 1997, respectively. Since 1999 he has been with the Kan Shan University of Technology, where he is currently Associate Professor and Chairman of the Department of Electronic Engineering. His current researches include current-mode circuits design, VLSI design, analog IC design, and analog IP design.Bin-Da Liu received the B.S., M.S., and Ph.D. degrees all in electrical engineering from the National Cheng Kung University, Tainan, Taiwan, in 1973, 1975, and 1983, respectively.Since 1977 he has been on the faculty of the National Cheng Kung University, where he is currently Distinguished Professor in the Department of Electrical Engineering and Director of the SoC Research Center. During 1983–1984, he was a Visiting Assistant Professor in the Department of Computer Science, University of Illinois at Urbana-Champaign. During 1988–1992, he was the Director of Electrical Laboratories, National Cheng Kung University. He was the Associate Chair of the Electrical Engineering Department during 1996–1999 and the Chair during 1999–2002. Since 1995 he has been a consultant of the Chip Implementation Center, National Applied Research Laboratories. He has published more than 190 technical papers. He also contributed chapters in the book Neural Networks and Systolic Array Design (D. Zhang, Ed. Singapore: World Scientific Publisher, 2002) and the book Accuracy Improvements in Linguistic Fuzzy Modeling (J. Casillas, O. Cordón, F. Herrera, and L. Magdalena, Eds. Heidelberg, Germany: Springer-Verlag, 2003). He is currently a CAS Associate Editor of the IEEE Circuits {&} Devices Magazine and an Associate Editor of the IEEE Transactions on Circuits and Systems-I. His current research interests include low power circuit design, SoC system integration and verification, and VLSI implementation for fuzzy-neural networks and audio/video signal processors.Jenn-Jiun Chen received the B.S. and M.S. degrees both in electrical engineering from the National Cheng Kung University, Tainan, Taiwan, in 2001 and 2003, respectively. His research interests are design and modeling of current mode circuit, low power analog circuit design, current mode filters, and instrumental amplifier in micro sensor applications. He received Chip Design Award from the Chip Implementation Center, National Applied Research Laboratories, in 2002.     

Extremely-Wide-Range Supply-Independent CMOS Voltage References for Telemetry-Powering Applications

This paper reports a voltage reference circuit in standard CMOS process. It exhibits excellent supply independency for a wide input voltage range, which is of great importance in telemetry-powered systems. This circuit is based on the well-known V_GS-reference supply-independent current reference circuit, but it is designed to serve as a voltage reference. While the reference current generated by this circuit varies with the supply voltage, a self-compensating mechanism can be found in voltage-mode operation of the circuit that results in a supply-independent reference voltage. This supply independency is well observed in the static operation of the circuit over an extremely wide input range, as well as in its dynamic behavior for high frequency ripples on the input voltage. Based on the proposed idea, a multi-output voltage reference and a CMOS DC level shifter are also designed. The proposed voltage reference circuits have been fabricated using MOSIS 1.6 μm standard CMOS process. The basic voltage reference provides 957 μV/V static supply dependency, rejects input ripples of up to 8 MHz by 60± 3dB, and consumes only 15.8–36.9 μA when the input voltage varies in the range 2.6–12 V. Amir M. Sodagar received the B.S. degree from K.N. Toosi (KNT) University of Technology, Tehran, Iran, and M.S. and Ph.D. degrees from Iran University of Science & Technology (IUST), Tehran, Iran all in Electrical Engineering in 1992, 1995, and 2000, respectively. From 1992 to 2000 he was with S. Rajaee University as a Lecturer. After receiving the Ph.D. degree until 2002 he was with the NSF Engineering Research Center for Wireless Integrated Micro Systems (WIMS), Electrical Engineering & Computer Science (EECS) Dept., University of Michigan as a Post-Doctoral Research Fellow. From 2002 to 2004 he was with S. Rajaee University and KNT University of Technology as an Assistant Professor and an Adjunct Professor, respectively, and since 2004 he has been with the University of Michigan as an Associate Visiting Research Scientist. Dr. Sodagar was known as the Outstanding Electrical Engineering Graduate Student of the IUST in 1995, and receiv ed the IUST's Best Ph.D. Research Achievement Award in 2000. He was also the recipient of S. Rajaee University's Distinguished Faculty Member Award for “1998–1999” and “1999–2000” academic years, and S. Rajaee University's Distinguished Researcher Award for “2002–2003” academic year. He was involved in the design of integrated circuits in collaboration with the Center for Semiconductor Research and Fabrication from 1994 to 1995, VLSI Circuits & Systems Laboratory at the University of Tehran from 1997 to 1998, and EMAD Semicon Company from 1998 to 2000. He has authored one book, authored/co-authored more than 20 journal and conference papers, and served as the technical paper reviewer for several IEEE journals/transactions and also conferences. Dr. Sodagar's research interests are generally in the field of mixed-signal integrated circuit design, and focused on: integrated circuits for neural recording & stimulation, telemetry powering and control of implantable microsystems, frequency synthesizers, analog building blocks, and transistor-level implementations of digital logic families. Khalil Najafi (IEEE S '84, M '86, SM '97, F'00) received the B.S., M.S., and the Ph.D. degree in 1980, 1981, and 1986 respectively, all in Electrical Engineering from the Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor. From 1986–1988 he was employed as a Research Fellow, from 1988–1990 as an Assistant Research Scientist, from 1990–1993 as an Assistant Professor, from 1993–1998 as an Associate Professor, and since September 1998 as a Professor and the Director of the Solid-State Electronics Laboratory, Department of Electrical Engineering and Computer Science, University of Michigan. His research interests include: micromachining technologies, micromachined sensors, actuators, and MEMS; analog integrated circuits; implantable biomedical microsystems; micropackaging; and low-power wireless sensing/actuating systems. Dr. Najafi was awarded a National Science Foundation Young Investigator Award from 1992–1997, was the recipient of the Beatrice Winner Award for Editorial Excellence at the 1986 International Solid-State Circuits Conference, of the Paul Rappaport Award for co-authoring the Best Paper published in the IEEE Transactions on Electron Devices, and of the Best Paper Award at ISSCC 1999. In 2003 he received the EECS Outstanding Achievement Award, in 2001 he received the Faculty recognition Award, and in 1994 the University of Michigan's “Henry Russel Award” for outstanding achievement and scholarship, and was selected as the “Professor of the Year” in 1993. In 1998 he was named the Arhtur F. Thurnau Professor for outstanding contributions to teaching and research, and received the College of Engineering's Research Excellence Award. He has been active in the field of solid-state sensors and actuators for more than twenty years, and has been involved in several conferences and workshops dealing with solid-state sensors and actuators, including the International Conference on Solid-State Sensors and Actuators, the Hilton-Head Solid-State Sensors and Actuators Workshop, and the IEEE/ASME Micro Electromechanical Systems (MEMS) Conference. Dr. Najafi is the Editor for Solid-State Sensors for IEEE Transactions on Electron Devices, an Associate Editor for the Journal of Micromechanics and Microengineering, Institute of Physics Publishing, and an editor for the Journal of Sensors and Materials. He also served as the Associate Editor for IEEE Journal of Solid-State Circuits from 2000–2004, and the associate editor for IEEE Trans. Biomedical Engineering from 1999–2000. He is a Fellow of the IEEE.     

A 1 V switchable CMOS LNA for 802.11A/B WLAN applications

A new dual-band, 2.4 and 5.2 GHz, combined LNA, which can operate at 1 V supply only, for WLAN application is presented. The switched transistor technique is used in the LNA. It could match the input port in two frequency bands and reduce one on-chip spiral inductor usage compared with [1, 2]. Theoretical analysis and transistor level simulation results using 0.18 μm CMOS process from Chartered Semiconductor are presented to demonstrate this idea. Wang-Chi Cheng received his B.Eng., M.Phil., and Ph.D. degrees in Electronic Engineering of the Chinese University of Hong Kong (CUHK) in 1999, 2001 and 2004. His research achievements during M.Phil. and Ph.D. studies were in the field of low voltage receiver front-end circuits design with CMOS technology. He joined the Electrical and Electronic Engineering department of Nanyang Technological University (NTU), Singapore, in May 2005 as a Research Fellow. Now, he is a Senior Engineer in charge of the UWB transceiver IC design in Hong Kong Applied Science and Technology Research Institute (ASTRI). His current research interests include 802.11 A/B WLAN and UWB transceiver design. He is also a paper reviewer of the IEEE Microwave and Wireless Components Letters. Jian-Guo Ma received his B.Sc. and M.Sc. in 1982 and 1988 respectively with honors from Lanzhou university of Chain, and Doctoral Degree in Engineering from Gerhard-Mercator University of Germany in 1996. From Jan. 1982 to March 1991, he has worked with Lanzhou university of China on RF & Microwave Engineering. Before he joined Nanyang Technological University in 1997, he was with Technical University of Nova Scotia, Canada. Now, he is a Professor of the University of Electronic Science and Technology of China. His research interests are: RFIC designs for wireless applications; RF characterization and modeling of semiconductor devices; RF interconnects and packaging; SoC and Applications; EMC/EMI in RFICs. He has published more than 150 technical papers and two books in above mentioned areas. He holds 6 patents in CMOS RFICs. He is now Associate Editor for IEEE Microwave and Wireless Components Letters. Kiat-Seng Yeo received his B.E. (Hons.) (Elect) in 1993, and Ph.D. (Elect. Eng.) in 1996 both from Nanyang Technological University, Singapore. He joined the School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore as a Lecturer in 1996, and became an Assistant Professor and an Associate Professor in 1999 and 2002, respectively. Professor Yeo provides consulting to statutory boards and multinational corporations in the areas of semiconductor devices and electronic circuit design. He has been extensively involved in the modeling and fabrication of small MOS/Bipolar integrated technologies for the last ten years. His research interests also include the design of new circuits and systems (based on scaled technologies) for low-voltage low-power applications; radio frequency integrated circuit (RF IC) design; integrated circuit design of BiCMOS/CMOS multiple-valued logic circuits, domino logic, and memories; and device characterization of deep submicrometer MOSFETs. Manh-Anh Do obtained his B.E. (Hons) (Elect.) in 1973, and Ph.D. (Elect. Eng.) in 1977 both from University of Canterbury, New Zealand. Between 1977 and 1989, he held various positions including: R & D engineer and production manager at Radio Engineering Ltd., research scientist at Fisheries Research Centre, New Zealand, and senior lecturer at National University of Singapore. He joined the School of Electrical and Electronic Engineering, Nanyang Technological University (NTU), Singapore as a senior lecturer in 1989, and obtained the Associate Professorship in 1996 and the Professorship in 2001. He has been a consultant for many projects in the Singapore electronic industry, and was the principal consultant for the design, testing and implementation of the $200 million Electronic Road Pricing (ERP) island-wide project in Singapore, from 1990 to 2001. His current research is on digital and mobile communications, RF IC design, mixed-signal circuits and intelligent transport systems. Before that, he specialsed in sonar designing, biomedical engineering and signal processing. Since 1995, he has been Head of Division of Circuits and Systems, School of EEE, NTU. He is a Fellow of IEE, UK, a Chartered Engineer (UK) and a Professional Engineer (Singapore).     

1.1 V Low-Power ΣΔ Modulator for 14-bit, 16 KHz A/D Conversion Using a New Low-Voltage Class-AB Op-amp

This paper presents the implementation of a second order modulator for a 1.1 V supply voltage. A new class-AB CMOS operational amplifier has been designed in order to achieve high-resolution under very-low-voltage operation. The modulator has been implemented using a 0.35 m CMOS technology with 0.65 V transistor threshold voltage. Experimental results show 14 bits of resolution over 16 kHz nyquist rate with an oversampling ratio of 160.Fernando Muñoz Chavero was born in El Saucejo, Sevilla, Spain. He received the Telecommunications Engineering and Ph.D. degrees from the University of Seville, Seville, Spain, in 1998 and 2002, respectively. Since 1997, he has been with the Department of Electronic Engineering, School of Engineering, University of Seville, where he has been an Associate Professor (1999). His research interests are related to low-voltage low-power analog circuit design, A/D and D/A conversion, and analog and mixed signal processing.Alfredo Pérez Vega-Leal was born in Seville, Spain. He received the Telecommunications Engineering and Ph.D. degrees from the University of Seville, Seville, Spain, in 1998 and 2003, respectively. Since 1995, he has been with the Department of Electronic Engineering, School of Engineering, University of Seville, as research student and became an Associate Professor in 1999. His research interests are related to low-voltage low-power analog circuit design, A/D and D/A conversion.Ramón González Carvajal was born in Seville, Spain. He received the Electrical Engineering and Ph.D. degrees from the University of Seville, Seville, Spain, in 1995 and 1999, respectively. Since 1996, he has been with the Department of Electronic Engineering, School of Engineering, University of Seville, where he has been an Associate Professor (1996), and Professor (2002). He has published more than 100 papers in International Journals and Conferences. His research interests are related to low-voltage low-power analog circuit design, A/D and D/A conversion, and analog and mixed signal processing.Antonio Torralba was born in Seville, Spain. He received the electrical engineering and Ph.D. degrees from the University of Seville, Seville, Spain, in 1983 and 1985, respectively. Since 1983, he has been with the Department of Electronic Engineering, School of Engineering, University of Seville, where he has been an Assistant professor, Associate Professor (1987), and Professor (1996). He has published 30 papers in journals and more than 80 papers in conferences. His research interests are in the design and modeling of low-voltage analog circuits, analog and mixed-signal design, analog to digital conversion, and electronic circuits and systems with application to control and communication.Jonathan Noel Tombs was born in Oxford, UK. He received the Electrical Engineering and Ph.D. degrees from Oxford University, UK, in 1987 and 1991, respectively. Since 1993, he has been with the Department of Electronic Engineering, School of Engineering, University of Seville, where he has been an Associate Professor (1997), and Professor (2002). He has published more than 50 papers in International Journals and Conferences. His research interests are related to Digital Design and system verification with VHDL, low-voltage low-power analog circuit design, A/D and D/A conversion and analog and mixed signal processing.Jaime Ramírez-Angulo is currently Klipsch Distinguished Professor, IEEE fellow and Director of the Mixed-Signal VLSI lab at the Klipsch School of Electrical and Computer Engineering, New Mexico State University (Las Cruces, New Mexico), USA. He received a degree in Communications and Electronic Engineering (Professional degree), a M.S.E.E. from the National Polytechnic Institute in Mexico City and a Dr.-Ing. degree form the University of Stuttgart in Stuttgart, Germany in 1974, 1976 and 1982 respectively. He was professor at the National Institute for Astrophysics Optics and Electronics (INAOE) and at Texas A&M University. His research is related to various aspects of design and test of analog and mixed-signal Very Large Scale Integrated Circuits.     

Fault Detection in Switched Current Circuits Using Built-in Transient Current Sensors

Switched current (SI) circuits use analogue memory cells as building blocks. In these cells, like in most analogue circuits, there are hard-to-detect faults with conventional test methods. A test approach based on a built-in dynamic current sensor (BIDCS), whose detection method weights the highest frequency components of the dynamic supply current of the circuit under test, makes possible the detection of these faults, taking into account the changes in the slope of the dynamic supply current induced by the fault. A study of the influence of these faults in neighbouring cells helps to minimize the number of BICS needed in SI circuits as is shown in two algorithmic analogue-to-digital converters. Yolanda Lechuga received a degree in Industrial Engineering from the University of Cantabria (Spain) in April 2000. Since then, she has been collaborating with the Microelectronics Engineering Group at the University of Cantabria, in the Electronics Technology, Systems and Automation Engineering Department. Since October 2000 she has been a post-graduate student, to be appointed as lecturer at this university, where she is working in her Ph.D. She is interested in supply current test methods, fault simulation, BIST and design for test of mixed signal integrated circuits. Román Mozuelos received a degree in Physics with electronics from the University of Cantabria, Spain. From 1991 to 1995 he was working on the development of quartz crystal oscillators. Currently, he is a Ph.D. student and an assistant teacher at the University of Cantabria in the Department of Electronics Technology. His interests include mixed-signal design and test, fault simulation, and supply current monitoring. Miguel A. Allende received his graduate degree in 1985 and Ph.D. degree in 1994, both from the University of Cantabria, Santander, Spain. In 1996, he became an Assistant Professor of Electronics Technology at the same Institution, where he is a member of the Microelectronics Engineering Group at the Electronics Technology, Systems and Automation Engineering Department in the Industrial and Telecommunication Engineering School. His research interests include design of VLSI circuits for industrial applications, test and DfT in digital VLSI communication circuits, and power supply current test of mixed, analogue and digital circuits. Mar Martínez received her graduate degree and Ph.D. from the University of Cantabria (Spain) in 1986 and 1990. She has been Assistant Professor of Electronic Technology at the University of Cantabria (Spain) since 1991. At present, she is a member of the Electronics Technology, Systems and Automation Engineering Department in the Industrial and Telecommunication Engineering School. She has participated in several EU and Spanish National Research Projects. Her main research interest is mixed, analogue and digital circuit testing, using techniques based on supply current monitoring. She is also interested in test and design for test in digital VLSI circuits. Salvador Bracho obtained his graduate degree and Ph.D. from the University of Seville (Spain) in 1967 and 1970. He was appointed Professor of Electronic Technology at the University of Cantabria (Spain) in 1973, where, at present, he is a member of the Electronics Technology, Systems and Automation Engineering Department in the Industrial and Telecommunication Engineering School. He has participated, as leader of the Microelectronics Engineering Group at the University of Cantabria, in more than twenty EU and Spanish National Research Projects. His primary research interest is in the area of test and design for test, such as full scan, partial scan or self-test techniques in digital VLSI communication circuits. He is also interested in mixed-signal, analogue and digital test, using methods based on power supply current monitoring. Another research interest is the design of analogue and digital VLSI circuits for industrial applications. Prof. Bracho is a member of the Institute of Electrical and Electronic Engineers.     

Voltage-Mode Universal Biquadratic Filters with One Input and Five Outputs

Four new voltage-mode universal biquadratic filters each with one input terminal and five output terminals are presented. Each of the first two proposed circuits uses four plus-type second-generation current conveyors, two grounded capacitors and five resistors. The third proposed circuit employs two plus-type second-generation current conveyors, one differential voltage current conveyor, two grounded capacitors and five resistors. The fourth proposed circuit employs two multi-output second-generation current conveyors, two grounded capacitors and five resistors. Each of the proposed circuits can realize all the standard filter functions; highpass, bandpass, lowpass, notch and allpass, simultaneously, without changing the passive elements. The proposed circuits enjoy the features of orthogonal controllable of resonance angular frequencies and quality factors, using only grounded capacitors as well as low active and passive sensitivities. Jiun-Wei Horng was born in Tainan, Taiwan, Republic of China, in 1971. He received the B.S. degree in Electronic Engineering from Chung Yuan Christian University, Chung-Li, in 1993, and the Ph.D. degree from National Taiwan University, Taipei, in 1997. From 1997 to 1999, he served as a Second-Lieutenant in China Army Force. From 1999 to 2000, he joined CHROMA ATE INC. where he worked in the area of video pattern generator technologies. From 2000 to 2005, he joined the Department of Electronic Engineering, Chung Yuan Christian University, Chung-Li, Taiwan as an Assistant Professor. Since 2005, he is an Associate Professor. His teaching and research interests are in the areas of Circuits and Systems, Analog and Digital Electronics, Active Filter Design and Current-Mode Signal Processing. Chun-Li Hou was born in Taipei, Taiwan, Republic of China, in 1951. He received the B.S. degree, M.S. degree, and Ph.D. degree in Electrical Engineering from National Taiwan University, Taipei, in 1974, 1976, and 1991, respectively. From 1977 to 1979, he taught as a lecture in Tamkang College. From 1981 to 1991, he taught as a lecture in the department of Electronic Engineering, Chung-Yuan Christian University, Chung, Taiwan. From 1992 until now, he taught there as an Associate Professor. His teaching and research interests are in the areas of Current-Mode Analog Circuit Analysis and Design, Active Network Synthesis Circuit theory and Applications. Chun-Ming Chang obtained his bachelor and master degrees, both in the field of electrical engineering, from National Cheng Kung University, Tainan, Taiwan, R.O. China, and his Ph.D. degree in the field of electronics and computer science from the University of Southampton, U.K. He had been an associate professor in Chung Yuan Christian University in Taiwan from 1985 to 1991, and has been a full professor in the same University since 1991. His research interest is divided by two relative fields, network synthesis before 1991 and analog circuit design after 1991. He had been a chairman of the electrical engineering department in Chung Yuan Christian University from 1995 to 1999. Recently, he was recommended for inclusion in The Contemporary Who's Who of Professionals 2004 Edition, and nominated by the Governing Board of Editors of the American Biographical Institute for the prestigious title MAN OF THE YEAR-2005, and became an Advisor of the ABI's distinguished RESEARCH BOARD OF ADVISORS due to the invention of Analytical Synthesis Method and OTA-Only-Without-C Circuits in the field of analog circuit design. Wen-Yaw Chung was born in Hsin-Chu, Taiwan, R.O.C., 1957. He received the B.S.E.E. and M.S. degrees from Chung Yuan Christian University, Chung Li, Taiwan, in 1979 and 1981 respectively, and the Ph.D. degree in Electrical and Computer Engineering from Mississippi State University, USA, in 1989. Subsequently, he joined the Advanced Microelectronics Division, Institute for Technology Development in Mississippi, where he was involved in the design of a bipolar optical data receiver. In 1990 he worked as a design manager for the Communication Product Division, United Microelectronics Corporation, Hsin-Chu, where he was involved in the design of analog CMOS data communication integrated circuits. Since 1991 he has been an Associate Professor in the Department of Electronic Engineering at Chung Yuan Christian University. His research interests include mixed-signal VLSI design, biomedical IC applications, sensor and actuator interfacing for deep submicron VLSI electronics.     

Controlled sink mobility for prolonging wireless sensor networks lifetime

This paper demonstrates the advantages of using controlled mobility in wireless sensor networks (WSNs) for increasing their lifetime, i.e., the period of time the network is able to provide its intended functionalities. More specifically, for WSNs that comprise a large number of statically placed sensor nodes transmitting data to a collection point (the sink), we show that by controlling the sink movements we can obtain remarkable lifetime improvements. In order to determine sink movements, we first define a Mixed Integer Linear Programming (MILP) analytical model whose solution determines those sink routes that maximize network lifetime. Our contribution expands further by defining the first heuristics for controlled sink movements that are fully distributed and localized. Our Greedy Maximum Residual Energy (GMRE) heuristic moves the sink from its current location to a new site as if drawn toward the area where nodes have the highest residual energy. We also introduce a simple distributed mobility scheme (Random Movement or RM) according to which the sink moves uncontrolled and randomly throughout the network. The different mobility schemes are compared through extensive ns2-based simulations in networks with different nodes deployment, data routing protocols, and constraints on the sink movements. In all considered scenarios, we observe that moving the sink always increases network lifetime. In particular, our experiments show that controlling the mobility of the sink leads to remarkable improvements, which are as high as sixfold compared to having the sink statically (and optimally) placed, and as high as twofold compared to uncontrolled mobility. Stefano Basagni holds a Ph.D. in electrical engineering from the University of Texas at Dallas (December 2001) and a Ph.D. in computer science from the University of Milano, Italy (May 1998). He received his B.Sc. degree in computer science from the University of Pisa, Italy, in 1991. Since Winter 2002 he is on faculty at the Department of Electrical and Computer Engineering at Northeastern University, in Boston, MA. From August 2000 to January 2002 he was professor of computer science at the Department of Computer Science of the Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas. Dr. Basagni’s current research interests concern research and implementation aspects of mobile networks and wireless communications systems, Bluetooth and sensor networking, definition and performance evaluation of network protocols and theoretical and practical aspects of distributed algorithms. Dr. Basagni has published over four dozens of referred technical papers and book chapters. He is also co-editor of two books. Dr. Basagni served as a guest editor of the special issue of the Journal on Special Topics in Mobile Networking and Applications (MONET) on Multipoint Communication in Wireless Mobile Networks, of the special issue on mobile ad hoc networks of the Wiley’s Interscience’s Wireless Communications & Mobile Networks journal, and of the Elsevier’s journal Algorithmica on algorithmic aspects of mobile computing and communications. Dr. Basagni serves as a member of the editorial board and of the technical program committee of ACM and IEEE journals and international conferences. He is a senior member of the ACM (including the ACM SIGMOBILE), senior member of the IEEE (Computer and Communication societies), and member of ASEE (American Society for Engineering Education). Alessio Carosi received the M.S. degree “summa cum laude” in Computer Science in 2004 from Rome University “La Sapienza.” He is currently a Ph.D. candidate in Computer Science at Rome University “La Sapienza.” His research interests include protocols for ad hoc and sensor networks, underwater systems and delay tolerant networking. Emanuel Melachrinoudis received the Ph.D. degree in industrial engineering and operations research from the University of Massachusetts, Amherst, MA. He is currently the Director of Industrial Engineering and Associate Chairman of the Department of Mechanical and Industrial Engineering at Northeastern University, Boston, MA. His research interests are in the areas of network optimization and multiple criteria optimization with applications to telecommunication networks, distribution networks, location and routing. He is a member of the Editorial Board of the International Journal of Operational Research. He has published in journals such as Management Science, Transportation Science, Networks, European Journal of Operational Research, Naval Research Logistics and IIE Transactions. Chiara Petrioli received the Laurea degree “summa cum laude” in computer science in 1993, and the Ph.D. degree in computer engineering in 1998, both from Rome University “La Sapienza,” Italy. She is currently Associate Professor with the Computer Science Department at Rome University “La Sapienza.” Her current work focuses on ad hoc and sensor networks, Delay Tolerant Networks, Personal Area Networks, Energy-conserving protocols, QoS in IP networks and Content Delivery Networks where she contributed around sixty papers published in prominent international journals and conferences. Prior to Rome University she was research associate at Politecnico di Milano and was working with the Italian Space agency (ASI) and Alenia Spazio. Dr. Petrioli was guest editor of the special issue on “Energy-conserving protocols in wireless Networks” of the ACM/Kluwer Journal on Special Topics in Mobile Networking and Applications (ACM MONET) and is associate editor of IEEE Transactions on Vehicular Technology, the ACM/Kluwer Wireless Networks journal, the Wiley InterScience Wireless Communications & Mobile Computing journal and the Elsevier Ad Hoc Networks journal. She has served in the organizing committee and technical program committee of several leading conferences in the area of networking and mobile computing including ACM Mobicom, ACM Mobihoc, IEEE ICC,IEEE Globecom. She is member of the steering committee of ACM Sensys and of the international conference on Mobile and Ubiquitous Systems: Networking and Services (Mobiquitous) and serves as member of the ACM SIGMOBILE executive committee. Dr. Petrioli was a Fulbright scholar. She is a senior member of IEEE and a member of ACM. Z. Maria Wang received her Bachelor degree in Electrical Engineering with the highest honor from Beijing Institute of Light Industry in China, her M.S. degree in Industrial Engineering/Operations Research from Dalhousie University, Canada and her Ph.D. in Industrial Engineering/Operations Research from Northeastern University, Boston. She served as a R&D Analyst for General Dynamics. Currently MS. Wang serves as an Optimization Analyst with Nomis Solutions, Inc.     

Wireless LANs Systems: An Advanced Resource Assignement Algorithm

The paper describes the design and simulation of a radio modem architecture, which provides wireless access to Internet in a single-hop, ad hoc network.The main emphasis is on the Medium Access Control (MAC) and Dynamic Link Control (DLC) layer’s design, and in particular on the adopted innovative scheduling algorithm, which has been developed to satisfy the system requirements of the WIND-FLEX radio modem. The algorithm is presented and compared to the Earliest Deadline First (EDF) solution.Several software simulation tests have been executed on the network, to test the performance of the system, in order to verify the capability of the scheduler algorithm to satisfy the expected requirements and the efficiency of the implemented solutions. Giuseppe Razzano was born in Roma, Italy, in 1974. He has graduated in Electronic Engineering “summa cum laude” and has received PhD in Communication Systems and Computer Science, in 2004 from University of Rome “La Sapienza”. From 2000 to 2001 he worked as research assistant at VTT electronics, in Finland. From 2004 to 2005 he worked as senior researcher at Forschungzentrum Telekommunikation Wien (Telecommunication Research Centre Vienna) in Austria. Currently, he works as System Engineer for Vitrociset S.p.A., working in a project funded by European Space Agency (ESA), for the development of a new generation space launcher vehicle (VEGA). In the past years, he worked in several projects funded by EC within the IST (Information Societies Technology) program, being also involved in projects in collaboration with Italian companies. His research is focused on resource management algorithms for wireless LANs and cellular networks. He is also interested in object-oriented programming and development methodologies. In these fields, he is author of several papers published in international journals and conferences. Francesco Delli Priscoli was born in Rome in 1962. He graduated in Electronic Engineering “summa cum laude” from the University of Rome “La Sapienza” in 1986. He received the Ph.D. in system engineering from the University of Rome “La Sapienza” in 1991. From 1986 to 1991 he worked in the “Studies and Experimentation” Department of Telespazio (Rome). Since 1991 he is working for the University of Rome “La Sapienza” where, at present, he is “Full Professor” and holds the courses “Automatic Controls”, “System Theory” and “Network Control and Management I and II”. In the framework of his activity, he researches in the nonlinear control theory and in the area of control-based resource management procedures for the third and forth generation of mobile systems. He is the author of about 150 technical papers on the above topics appeared on major international reviews (about 50) and conferences (about 100). In 2000 he has been scientific consultant for the Italian Council of Ministers in the framework of the auction for the assignment of the Italian Universal Mobile Telecommunication System (UMTS) licensees. He is an associate editor of Control Engineering Practice and a member of the IFAC Technical Committee on “Networked Systems”. He is/has been scientific responsible, for the University of Rome “La Sapienza”, of 17 projects financed by the European Union (fourth, fifth and sixth framework programmes) or by the European Space Agency (ESA), dealing with resource management for UMTS and broadband terrestrial and satellite wireless systems. He is also a project evaluator for the European Commission. Roberto Cusani received the “laurea” degree in Electronic Engineering (cum laude) and the Ph.D. in Communication Systems and Computer Science from the University of Rome “La Sapienza”. From 1986 to 1990 he was research engineer at the University of Rome “Tor Vergata”, teaching Digital Signal Processing. In 1991 he joined the University of Rome “La Sapienza” as Associate Professor of Signal Theory. In 2000 he becomes Full Professor and teaches Information Theory and Coding, and Mobile Communications. His former research activities concern transmission and coding of signals and images, with emphasis on random processes, spectral estimation and image coding. Since 1992 he focused his activities in the field of the digital communication systems, with emphasis on channel equalisation and coding for HF and radio-mobile (GSM) links, on the design of CDMA receivers for UMTS and, in general, on the use of digital techniques within telecommunication equipments. More recently his interests also includes the study of MAC (Multiple Access Control) protocols with application to wireless area networks (WLANs), reconfigurable ad-hoc networks and satellite links. He is author of more than 100 publications in international journals and conferences, of the text-book “Teoria dei Segnali” and of five patents regarding telecommunication applications. He was involved in many research programs, both national and international, and in projects with the industrie.     

Electronic Implementation of Multirate Sigma-Delta Modulators Using CMOS Technologies

Multirating has been recently proposed to reduce the frequency rate of the first integrator(s) of a single-loop, or the first stage(s) of a cascade, Sigma-Delta modulator (SDM). This is a promising technique for the design of high speed, low-power modulators, as the first integrator (or stage) in the chain primarily determines the performances of the modulator, as well as its power consumption. This paper presents the first implementation of a 2nd-order multirate SDM, showing different circuit solutions. The experimental results obtained with a prototype in a standard 0.6 μm CMOS technology shows that different clock rates can be selected for each integrator of a SDM. Alfredo Pérez Vega-Leal was born in Seville, Spain. He received the Telecommunications Engineering and Ph.D. degrees from the University of Seville, Seville, Spain, in 1998 and 2003, respectively. Since 1995, he has been with the Department of Electronic Engineering, School of Engineering, University of Seville, as research student and became an Associate Professor in 1999. His research interests are related to low-voltage low-power analog circuit design, A/D and D/A conversion. Francisco Colodro was born in Peal de Becerro (Jaén), Spain, in 1968. He received the Ingeniero de Telecomunicación degree from the University of Vigo, Vigo, Spain, in 1992, and the Ph.D. degree from the University of Sevilla, Sevilla, Spain, in 1997. In 1992 he joined the Department of Electronics Engineering, University of Sevilla, where he is currently and Associate Professor. His research interests are in the architectural study of Σ Δ modulators, the implementation of ADCs based on Σ Δ modulators, and application of electronic circuits and systems to communication. Marta Laguna was born in Seville, Spain. She received the Telecommunications Engineering degree from the University of Seville in 2002. She is currently working toward the Ph.D. degree. Her doctoral work focuses on the design of continuous-time sigma-delta modulators. Since 2001, she has been with the Department of Electronic Engineering, School of Engineering, University of Seville, as research student and became an assistant teacher in 2004. Her research interests are high-speed analog-to-digital converters and sigma-delta modulators. Antonio Torralba (M'89–SM'02) was born in Sevilla, Spain, in 1960. He received the electrical engineering and Ph.D. degrees from the University of Sevilla in 1983, and 1985, respectively. Since 1983 he has been with the Department of Electronics Engineering, School of Engineering, University of Sevilla, where he has been Associate Professor in 1987, and Full Professor since 1996, leading a research group on mixed signal design. In 1999 he made a short stay at the Department of Electrical Engineering, NMSU, and he is presently in the Department of Electrical Engineering, TAMU for a Sabbatical stay. His interests include low-voltage analog circuits and systems, analog to digital conversion, Σ Δ modulators, and electronic circuits and systems with application to control and communication. In these fields he has published around 40 journal papers and more than 100 conference papers, and he holds 2 international patents.     

A Joint MAC-PHY Approach for Medium Access Control in VBR MC-CDMA Broadband Indoor Connections

Multicarrier Code Division Multiple Access (MC-CDMA) techniques were originally proposed at mid of 90's for wideband multi-user communications in wireless environments characterized by hostile propagation characteristics. In this work, the design of a MC-CDMA-based infrastructure is considered for VBR broadband indoor connections with real-time asynchronous multiple access. At the present time, Broadband Fixed Wireless Access (BFWA) standards like IEEE 802.16 and HIPERMAN can bring broadband services inside buildings, but indoor access should be conveniently provided by a local area connection. The capability of MC-CDMA of supporting asynchronous multi-user variable-bit-rate (VBR) transmission is exploited jointly with an efficient and real-time Medium Access Control (MAC) strategy in order to allow a significant number of indoor VBR users to transmit information in CDMA modality with different quality of service (QoS) profiles. Different classes of users are defined at the MAC level. The available radio resources (i.e. the orthogonal subchannels) are selectively attributed to transmitting users depending on their performance achieved at MAC level and measured by an “intelligent” gateway. When the quality level is not satisfactory for one or more users, the AP issues a decrease of the data rate for such users while providing them with an increased number of subcarriers, guaranteeing a slower transmission fostered against frequency-selective channel distortions. The paper presents an overview of the system and tests its performance through extensive simulations. The proposed joint MAC-PHY approach demonstrates good performance in terms of achieved throughput and high flexibility in radio resource management.This work has been partially supported in Italy by the “NETMOBS -Network-supported Mobility for the Student” – Create-NET project funding, 2005. Claudio Sacchi was born in Genoa (Italy) in 1965. He obtained the Laurea degree in Electronic Engineering, and the Ph.D. in Space Science and Engineering at the University of Genoa (Italy). Since August 2002, Dr. Sacchi has been holding a position as assistant professor at the Faculty of Engineering of the University of Trento (Italy). In 2004, he was appointed by the Department of Information and Communication Technology of the University of Trento as leader of the Research Program titled: “Wireless and Satellite Communications”. The research interests of Dr. Sacchi are focused on wideband mobile and satellite transmission systems based on space, time and frequency diversity, multi-user receivers based on non conventional techniques, and high-frequency ultra-wideband satellite communications. Dr. Sacchi is author and co-author of more than 40 papers published in international journals and conferences. He is member of IEEE. Giovanni Berlanda Scorza was born in Trento (Italy) in 1978. He received the Laurea in Telecommunications Engineering in 2002 at the “Politecnico di Milano” Technical University. Since October 2002, he is a Ph.D student at the Information and Communications Technologies (ICT) International Doctorate School of the University of Trento. His research interests mainly concern with specific aspects related to OFDM and MC-CDMA transmission techniques like e.g.: computationally-affordable multi-user receivers, Medium Access Control strategies, multicarrier-based multiplexing of multi-layered MPEG-4 coded video streams, etc. Fabrizio Granelli was born in Genoa in 1972. He received the “Laurea” (M.Sc.) degree in Electronic Engineering from the University of Genoa, Italy, in 1997, and the Ph.D. in Telecommunications from the same university, in 2001. Since 2000 he is carrying on his teaching activity as Assistant Professor in Telecommunications at the Dept. of Information and Communication Technology – University of Trento (Italy). In August 2004, he was visiting professor at the State University of Campinas (Brasil). He is author or co-author of more than 50 papers published in international journals, books and conferences, and he is member of the Technical Committee of the International Conference on Communications (ICC2003, ICC2004 and ICC2005) and Global Telecommunications Conference (GLOBECOM2003 and GLOBECOM2004). Dr. Granelli is guest-editor of ACM Journal on Mobile Networks and Applications, special issue on “WLAN Optimization at the MAC and Network Levels” and Co-Chair of 10th IEEE Workshop on Computer-Aided Modeling, Analysis, and Design of Communication Links and Networks (CAMAD'04). Dr. Granelli is General Vice-Chair of the First International Conference on Wireless Internet (WICON'05). His main research activities are in the field of networking and signal processing, with particular reference to network performance modeling, medium access control, wireless networks, next-generation IP, and video transmission over packet networks. Francesco G.B. De Natale received the Laurea in Electronic Engineering in 1990, and the Ph.D. in Telecommunications in 1994, both from the University of Genoa, Italy. In 1995–96 he was Visiting Professor at the University of Trento, Italy and from 1996 to 1999 Assistant Professor at the University of Cagliari, Italy. At present he is Full Professor of Telecommunications at the University of Trento, where he coordinates the didactic activities of the Bachelor and Master Courses in Telecommunications Engineering. Prof. De Natale is Deputy Head of the Dept. of Information and Communication Technologies, where he leads the research activities of the Multimedia Communications Lab. The research interests of Prof. De Natale are focused on image and signal processing, with particular attention to multimedia data compression, processing and transmission. He was General Co-Chair of the Packet Video Workshop in 2000 and is Technical Program Co-Chair of the IEEE Intl. Conf. on Image Processing to be held in 2005. In 1998 he was co-recipient of the IEEE Chester-Sall Best Paper Award. Prof. De Natale is a Senior Member of IEEE.