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Events for May 11, 2011
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Network Modulation: Simultaneous Optimality in Multi-User Communication
Wed, May 11, 2011 @ 02:00 PM - 03:00 PM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Speaker: Yuval Kochman, Massachusetts Institute of Technology
Talk Title: Network Modulation: Simultaneous Optimality in Multi-User Communication
Abstract: The choice of modulation domain plays a major role in communications, both in deriving performance limits and in the design of practical schemes which decouple the signal processing task of channel equalization from coding. Thus, choosing the "right" basis is of central importance. For example, the capacity of the Gaussian inter-symbol interference (ISI) channel is given by the water-filling solution, applied in the frequency domain; the same transformation also allows to use popular schemes such as Orthogonal Frequency-Division Multiplexing (OFDM) which employs the discrete Fourier transform. The singular-value decomposition (SVD) plays a similar role for multiple-input multiple-output (MIMO) channels. Common to both cases is diagonalization: they yield parallel independent equivalent channels. But do we really need such orthogonality? Capacity can be achieved for both the ISI and MIMO channels using non-orthogonal equivalent channels, by a receiver which performs triagularlization of the channel (rather than diagonalization) and then decision-feedback equalization or successive interference cancellation (SIC). This is done without performing any transformation at the encoder. It is therefore natural to ask, what can be achieved by allowing (in addition to linear processing at the receiver) both an encoder transformation (linear unitary processing) and SIC.
In this work we show that in various communication scenarios, such a combination is indeed advantageous. In particular, the degrees of freedom earned by allowing SIC may be used for obtaining a domain which is simultaneously optimal for two users. We demonstrate this advantage by applying the network modulation approach to several problems. For some cases of joint source-channel coding over MIMO broadcast channels, we are able to derive the optimal distortion region by applying a hybrid digital-analog scheme over the equivalent triangular channels. For the two-way MIMO relay channel we find the capacity in the high signal-to-noise ratio limit by using physical-layer modulo-lattice arithmetics over these equivalent channels. For the Gaussian common-message MIMO broadcast channel, as well as for Gaussian rateless coding, we get schemes which allow to achieve the known optimal performance using standard scalar codes.
Joint work with Anatoly Khina, Uri Erez and Gregory W. Wornell.
Biography: Yuval Kochman received his B.Sc., M.Sc. and Ph.D. degrees from Tel Aviv University in 1993, 2003 and 2010, respectively. He is a postdoctoral associate at the at the Signals, Information and Algorithms Laboratory at the Massachusetts Institute of Technology (MIT), since 2009. Outside academia, he has worked in the areas of radar and digital communications. His research interests include information theory, communications and signal processing.
Host: Giuseppe Caire, caire@usc.edu, EEB 540, x04683
Location: Hughes Aircraft Electrical Engineering Center (EEB) - 248
Audiences: Everyone Is Invited
Contact: Gerrielyn Ramos
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Algorithmic Aspects of Sensor Networking and Green Buildings of the Future Internet
Wed, May 11, 2011 @ 03:30 PM - 04:30 PM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Speaker: Sotiris Nikoletseas, Professor, Computer Engineering and Informatics Department of Patras University, and Greece Director, SensorsLab at the Computer Technology Institute (CTI)
Talk Title: Algorithmic Aspects of Sensor Networking and Green Buildings of the Future Internet
Abstract: The talk is structured into three parts. We first present representative algorithms for important problems in wireless sensor networks, such as data propagation, energy optimization and mobility management. We examine key protocol design techniques as well as performance evaluation aspects by both analytic means and large scale algorithmic engineering, including actual implementation in experimental test-beds.
We then discuss characteristic research challenges of energy efficient buildings of the Future Internet, focusing on smart service provision in the context of IPv6 sensor technologies. In particular, we focus on the objectives, approach and services of the on-going EU-funded project HOBNET (HOlistic Platform Design for Smart Buildings of the Future InterNET, www.hobnet-project.eu); we discuss the complementarity of smart automation to other components of energy informatics, such as cognitive, user-aware energy management and smart grid technologies.
We conclude with some relevant work in progress, mainly related to the new paradigm of radiation aware wireless networking.
Biography: Sotiris Nikoletseas is a Professor at the Computer Engineering and Informatics Department of Patras University, Greece and Director of the SensorsLab at the Computer Technology Institute (CTI). He has been a Visiting Professor at the Universities of Geneva and Ottawa. His research interests include algorithmic aspects of wireless sensor networks and ad-hoc mobile computing, fundamental aspects of modern networking (focus on efficiency and reliability), probabilistic techniques and random graphs, average case analysis and probabilistic algorithms, computational complexity and approximation algorithms, algorithmic engineering and large scale simulation. He has coauthored over 150 publications in international Journals and refereed Conferences, 18 Invited Chapters in Books by major publishers and two Books, one on the Probabilistic Method and another one on theoretical aspects of sensor networks (Springer Verlag). He has served as the Program Committee Chair of several Conferences (including ALGOSENSORS 2011, MOBIWAC 2011, SEA 2005, MSWiM 2007 and DCOSS 2008), and as Associate Editor, Editor of Special Issues and Member of the Editorial Board of major Journals (like TCS, IEEE TC, COMNET, IJDSN, JEA). He has co-initiated international events related to sensor networks (ALGOSENSORS, DCOSS). He has coordinated several externally funded European Union R&D Projects related to fundamental aspects of modern networks.
Host: Professor Viktor K. Prasanna
Location: 248
Audiences: Everyone Is Invited
Contact: Janice Thompson
