CSL General Event Calendar
CSL General Event Calendar
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Event Detail Information
Event Detail Information
Signal Processing Seminar
Title: Signal Processing for Clipping Distortion in IM/DD Optical OFDM Systems
Speaker: Dr. Brian Krongold
Dept. of Electrical & Electronic Eng.
University of Melbourne, Australia
Date: Wednesday, February 22, 2012
Time: 4:00 - 5:00 pm
Location: 4269 Beckman Institute
Abstract: This talk considers the use of orthogonal frequency-division multiplexing (OFDM) for intensity-modulated, direct-detected (IM/DD) optical links. Due to the unipolarity of the IM/DD channel, asymmetric clipping and associated nonlinear distortion is inevitable, resulting in an unfavourable DC power and a significant performance penalty. We first consider an intelligent approach to distortion utilization in asymmetrically-clipped optical OFDM (ACO-OFDM) which provides a significant performance boost. Following this, we discuss a new framework to enable IM/DD optical OFDM transmission where certain subchannels are reserved to produce a negative peak-cancelling signal that guarantees a unipolar OFDM signal. We will show how DC-biased OFDM and ACO-OFDM are simply special cases of this framework. More importantly, we will explain how this framework offers greater flexibility and a better tradeoff between power and spectral efficiency for a given link.
Biography: Brian Krongold received the B.S., M.S. and Ph.D. degrees in electrical engineering in 1995, 1997, and 2001, respectively, from the University of Illinois at Urbana-Champaign. Brian joined the University of Melbourne in December 2001 as a Research Fellow, and is currently a Senior Lecturer. In 2011, he spent five months on sabbatical at Alcatel-Lucent Bell Labs in Murray Hill, New Jersey working on energy-efficient optical communications. As a graduate student, he was a visiting researcher at Rice University in Spring 1999 and the Electronics and Telecommunications Research Institute (ETRI) in Taejon, South Korea in Summer 1998. Brian received the second prize in the Student Paper Contest at the 2001 Asilomar Conference on Signals, Systems, and Computers, and the Best Paper Award at the 2006 European Wireless Conference. His work with Prof. Doug Jones on active constellation extension for OFDM PAPR reduction is part of the DVB-T2 digital video broadcast standard.
