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Events for March 07, 2011
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Network Interference Management via Interference Alignment for Wireless Communications and Distributed Storage Systems
Mon, Mar 07, 2011 @ 11:00 AM - 12:00 PM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Speaker: Viveck R. Cadambe, University of California, Irvine
Talk Title: Network Interference Management via Interference Alignment for Wireless Communications and Distributed Storage Systems
Abstract: Our current times are witnessing a veritable explosion in the number of mobile devices with network connectivity. This explosion in the number of mobile devices which will guzzle data is resulting in bandwidth is becoming an increasingly scarce resource. The surge in the demand for data calls for new techniques to understand and improve the capacity (data rates) of wireless networks. In this talk, I will describe and explore a new technique to manage interference, which is the primary bottleneck of rates of communication in wireless communication networks.
A widely held belief in wireless network design, and also a formal conjecture, is that for a wireless network with K interfering users competing for the same spectrum (also known as the wireless interference network), it is optimal from a network capacity (degrees of freedom) perspective to divide the spectrum among the users like cutting a cake. This cake cutting view of spectrum access also known as orthogonalization enables each user in the interference network to get a fraction of 1/K of the spectrum free of interference. The cake cutting view of spectrum access lies at the heart of the design of most current wireless communication systems. In this talk, we will show that this cake cutting view of spectrum access is flawed and show that each of the K users of an interference network can essentially get 'half the cake', i.e., each user can simultaneously get half the spectrum free of interference. To show this, the strategy of "interference alignment", which is a far more effective interference management strategy as compared to orthogonalization, will be presented and described in detail. The talk will explore the impact of interference alignment on fundamental design issues of wireless communication systems and briefly describe challenges for the design of future generation wireless systems.
The talk will also explore a second application of interference alignment - erasure coding for distributed storage systems. With the advent of cloud computing and storage, the amount of data stored in distributed data storage systems (such as data centers) is scaling at an unprecedented rate. This scaling of stored data has motivated the use of erasure coding as a technique to build redundancy in distributed storage systems, to replace the conventional redundancy design strategy of replication. While erasure coding is attractive because it provides higher redundancy for a given amount (cost) of storage as compared to the conventional strategy of replication, practical implementation of coding for large distributed storage systems faces one principal bottleneck - the efficiency of repair when a storage device (node) fails in the distributed storage system. In the second part of this talk, by connecting the repair problem to interference alignment, I will (briefly) describe codes which improved repair efficiency and thus potentially relieve an important obstacle in the use of erasure coding for distributed storage systems.
Biography: Viveck R. Cadambe received his B.Tech and M.Tech. degrees in Electrical Engineering from the Indian Institute of Technology Madras, Chennai, India in 2006. He is currently working toward my Ph.D. degree at the University of California, Irvine. His research interests include multiuser information theory and wireless networks. In the summer of 2010, he was an intern in the Communication and Collaboration Systems Group at Microsoft Research, Redmond. Mr. Cadambe is a recipient of the 2009 IEEE Information Theory Society Paper Award and the UCI Electrical Engineering and Computer Science Department Best Paper Award for 2008-09. He also received the University of California, Irvine CPCC graduate fellowship for the year 2007-08.
Host: Giuseppe Caire, caire@usc.edu
Location: Hughes Aircraft Electrical Engineering Center (EEB) - 248
Audiences: Everyone Is Invited
Contact: Gerrielyn Ramos
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EE-Electrophysics Seminar
Mon, Mar 07, 2011 @ 01:00 PM - 02:00 PM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Speaker: Daniel Feezell, Materials Department, University of California, Santa Barbara
Talk Title: Status and Future of Nonpolar/Semipolar III-Nitride Materials and Devices
Abstract: III-Nitride materials enable a wide variety of high-impact technologies, including solid-state lighting, high-density optical data storage, energy efficient displays, and next-generation power electronics. Commercially available III-Nitride devices are grown on the polar c-plane of the wurtzite crystal, and their performance is adversely affected by the presence of polarization-related electric fields. As an alternative to conventional c-plane technologies, growth of III-Nitride structures on nonpolar/semipolar planes presents a viable approach to reducing or eliminating the issues associated with polarization-related electric fields. Optical devices fabricated on these alternative planes emerge with several inherent advantages, including improved radiative efficiency, increased design flexibility, and the potential for superior performance in the elusive green spectral region. In this talk, I will review the unique characteristics of nonpolar/semipolar III-Nitrides and discuss the application of this materials platform to the development of high-performance laser diodes and light-emitting diodes. I will conclude by proposing several future research directions that utilize nonpolar/semipolar III-Nitride technology.
Biography: Daniel Feezell completed his Ph.D. in Electrical Engineering at the University of California, Santa Barbara (UCSB) in 2005 for work on InP-based vertical-cavity surface-emitting lasers. He is currently a Project Scientist in the Solid-State Lighting and Energy Center at UCSB, where his research interests include growth, fabrication, and characterization of nonpolar/semipolar III-Nitrides for energy efficiency applications. Prior to joining UCSB he was a Senior Device Scientist and the first employee at Soraa, Inc., where he developed high-performance III-Nitride laser diodes and light-emitting diodes. For his role in the achievement of the first nonpolar III-Nitride laser diodes he received the 30th Annual Japanese Journal of Applied Physics Paper Award. He also invented an AlGaN-cladding-free nonpolar laser diode structure that is currently being utilized in cutting-edge industry products. For this work he received a commendation for excellence in technical communication from Laser Focus World magazine. He is the author or co-author of more than 30 peer-reviewed conference and journal publications, and has received several patents.
Host: EE-Electrophysics
More Info: ee.usc.edu/news/seminars/eepLocation: Hughes Aircraft Electrical Engineering Center (EEB) - 248
Audiences: Everyone Is Invited
Contact: Marilyn Poplawski
Event Link: ee.usc.edu/news/seminars/eep
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Lightwave Modulators: Early Research at Bell Labs
Mon, Mar 07, 2011 @ 02:00 PM - 03:00 PM
Ming Hsieh Department of Electrical and Computer Engineering
Conferences, Lectures, & Seminars
Speaker: Ivan P. Kaminow, EECS, UC Berkeley
Talk Title: Lightwave Modulators: Early Research at Bell Labs
Abstract: Ted Maimanâs announcement of the ruby laser in May 1960 created great excitement worldwide, and particularly at Bell Labs. I was in the Microwave Systems Research Lab, soon to become the Lightwave Systems Research Lab, in Holmdel, NJ. Many of my colleagues decided to pursue laser research. Based on my experience with microwave systems, I decided to explore broadband light modulators that would be key for any telecom system. In my talk, I plan to touch on some of the highlights of a 15-year period of research on electrooptic modulators in the Bell Labs ambience. I include a 9 GHz travelling wave modulator, studies of electrooptic materials and photonic integrated circuits.
Biography: Ivan Kaminow retired from Bell Labs in 1996 after a 42-year career (1954-1996), mostly in lightwave research. At Bell Labs, he did seminal studies on electrooptic modulators and materials, Raman scattering in ferroelectrics, integrated optics (including titanium-diffused lithium niobate modulators), semiconductor lasers (including the DBR laser, ridge waveguide InGaAsP laser and multi-frequency laser), birefringent optical fibers, and WDM lightwave networks. Later, as Head of the Photonic Networks and Components Research Department, he led research on WDM components (including the erbium-doped fiber amplifier, waveguide grating router and the fiber Fabry-Perot resonator), and on WDM local and wide area networks. Earlier (1952-1954), he did research on microwave antenna arrays at Hughes Aircraft Company.
After retiring from Bell Labs, he served as IEEE Congressional Fellow on the staffs of the House Science Committee and the Congressional Research Service (Science Policy Research Division) in the Library of Congress. From 1997 to 1999, he returned to Lucent Bell Labs as a part-time Consultant. He also established Kaminow Lightwave Technology to provide consulting services to various technology companies, and to patent and litigation law firms. In 1999 he served as Senior Science Advisor to the Optical Society of America in Washington. He also served on a number of professional committees. He received degrees from Union College (BSEE), UCLA (MSE) and Harvard (AM, Ph.D.). He was a Hughes Fellow at UCLA and a Bell Labs Fellow at Harvard.
He has been Visiting Professor at Princeton, Berkeley, Columbia, the University of Tokyo, and Kwangju University (Korea). Currently, he is Adjunct Professor in EECS at University of California, Berkeley, where he has been teaching since 2004 (ee290F. Advanced Topics in Photonics [spring 2004]; ee233. Lightwave Systems [spring 2006]; seminar on Plasmonics [spring, fall 2007] and seminar on Photonics and Plasmonics [spring, fall 2008; spring, fall 2009; spring, fall 2010]; spring 2011).
He has published over 240 papers, received 47 patents, and has written or co-edited 5 books, the most recent being "Optical Fiber Telecommunications V A&B," co-edited with Tingye Li and Alan Willner, Academic Press/Elsevier (2008). Kaminow is a Life Fellow of IEEE, and Fellow of APS and OSA. He is the recipient of the Bell Labs Distinguished Member of Technical Staff Award, IEEE Quantum Electronics Award, OSA Charles Townes Award, IEEE/LEOS/OSA John Tyndall Award, IEEE Third Millennium Medal, Union College Alumni Gold Medal and IEEE Photonics Award. He is a member of the National Academy of Engineering, a Diplomate of the American Board of Laser Surgery, and a Fellow of the New York Academy of Medicine.
Host: Alan Willner, willner@usc.edu
Location: Hughes Aircraft Electrical Engineering Center (EEB) - 539
Audiences: Everyone Is Invited
Contact: Gerrielyn Ramos
