University of California, Riverside

Department of Electrical and Computer Engineering

Hybrid Sparse/Diffuse Channels: Channel Models, Bayesian Estimators and Analysis

Hybrid Sparse/Diffuse Channels: Channel Models, Bayesian Estimators and Analysis

Hybrid Sparse/Diffuse Channels: Channel Models, Bayesian Estimators and Analysis

January 23, 2012 - 2:00 pm
Winston Chung Hall, 205/206

Dr. Urbashi Mitra


We will review prior work in the area of channel estimation for wide band channels such as ultrawide-band radio and underwater acoustic systems. In such systems, individual multipath can often be re-solved resulting in channels with some structure. Sparse and clustered channel estimation strategies will be considered. In some cases, however, experimental propagation data suggests that such wide-band channels are more complex. Thus, herein we also propose a novel channel model based on both diffuse and sparse components. Tailored to this hybrid model, channel estimators are designed for different scenarios which differ in the amount of side information available at the receiver. Addi-tionally, an Expectation-Maximization based algorithm to estimate the power delay profile of the dif-fuse component is proposed. The proposed channel estimation methods are compared to unstruc-tured and purely sparse estimators. The numerical results show that the new channel estimation schemes considerably improve the estimation accuracy and the bit error rate performance over con-ventional channel estimators. Further, a mean-squared error analysis of the proposed estimators is conducted in two asymptotic regimes: high SNR and low SNR enabling a simple characterization and thus comparison of the proposed estimators.


Urbashi Mitra received the B.S. and the M.S. degrees from the University of California at Berkeley and her Ph.D. from Princeton University. After a six year stint at the Ohio State University, she joined the Department of Electrical Engineering at the University of Southern California, Los Angeles, where she is currently a Professor. Dr. Mitra has been an Associate Editor for the following IEEE publica-tions: Transactions on Information Theory (2007-2011), Journal of Oceanic Engineering (2006-2011), and Transactions on Communications (1996-2001). She was a member of the IEEE Information The-ory Society's Board of Governors (2002-2007) and begins a third term in 2012. She is the recipient of: 2012 NAE Lillian Gilbreth Lectureship, 2011 USC Zumberge Interdisciplinary Innovation Fund (with M. El-Naggar), USC Center for Excellence in Research Fellowship (2010-2013), the Viterbi School of Engi-neering Dean’s Faculty Service Award (2009), USC Mellon Mentoring Award (2008), IEEE Fellow (2007), Texas Instruments Visiting Professor (Fall 2002, Rice University), 2001 Okawa Foundation Award, 2000 Lumley Award for Research (OSU College of Engineering), 1997 MacQuigg Award for Teaching (OSU College of Engineering), and a 1996 National Science Foundation (NSF) CAREER Award. Dr. Mitra has held visiting appointments at: the Delft University of Technology, Stanford Univer-sity, Rice University, and the Eurecom Institute. She served as co-Director of the Communication Sci-ences Institute at the University of Southern California from 2004-2007.

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