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Generalized Discrete Fourier Transform with Nonlinear Phase: A Time-Frequency Method

Event Date: October 20, 2010
Speaker: Dr. Ali Akansu
Speaker Affiliation: Department of Electrical and Computer Engineering, New Jersey Institute of Technology
Sponsor: Communications, Networking, Signal and Image Processing
Time: 5:00 PM
Location: EE 118
Contact Name: Ilya Pollak
Contact Phone: (765) 494-5916
Contact Email:

Constant modulus discrete time transforms like discrete Fourier transform (DFT), Walsh transform, and Gold codes have been favored in RF engineering applications due to their peak-to-average power ratio (PAPR) efficiency, and successfully deployed in many wireline-wireless communications and radar technologies over several decades.  We will present a generalized framework for uncountable set of constant amplitude DFT with nonlinear phase by exploiting the entire phase space.  It will be shown that Generalized DFT (GDFT) offers sizable improvements with respect to correlation metrics over DFT, Walsh, Gold codes, and leading to improved performance in multi-carrier communications scenarios considered.  We will show that known constant modulus code families are merely special solutions of the proposed GDFT framework. Design methods offering computationally efficient implementations of GDFT will be discussed. GDFT based CDMA and OFDM communications systems will be shown to outperform DFT based systems.


Ali N. Akansu received his B.S. degree from the Technical University of Istanbul, Turkey, M.S. and Ph.D. degrees from Polytechnic, Brooklyn, New York, all in Electrical Engineering.  Since 1987, he has been on the faculty of the Department of Electrical and Computer Engineering at the New Jersey Institute of Technology, Newark, NJ.  He was a Founding Director of the New Jersey Center for Multimedia Research and NSF Industry-University Cooperative Research Center for Digital Video. Currently, he is serving as the Chairperson of NJIT Faculty Council.

Ali N. Akansu was the Vice President for Research and Development of IDT Corporation [NYSE: IDT].  He was the founding President and CEO of PixWave, Inc., and Senior VP for Technology Development of TV.TV (IDT subsidiaries).  He has sat on the boards of several companies and an investment fund.  He was an academic visitor at David Sarnoff Research Center, IBM T.J. Watson Research Center, and at GEC-Marconi Electronic Systems Corp.  Most recently, he was a Visiting Professor at the Courant Institute of Mathematical Sciences of the New York University performing research on Quantitative Finance and Electronic Trading.  He has published numerous articles and several books with his students and colleagues on their joint research work.  He administered and managed a number of research programs and product development projects in academia and private sector, funded by the State & Federal Government agencies, and industry.  His current research interests include signal and transform theories, and applications in finance, next generation Internet, wireless OFDM/CDMA communications, and RF engineering.  He is a Fellow of the IEEE.