Princeton University

School of Engineering & Applied Science

Gaussian Channels: Mutual Information-MMSE at Every SNR

Ronit Bustin, Princeton University
E-Quad B205
Monday, August 10, 2015 - 3:00pm to 4:00pm

Abstract:  Multi-user information theory presents many open problems even in seemingly simple settings such as the two-user Gaussian interference channel.  Here we consider two cases of multi-user scalar Gaussian channels; the cases of one, or two, transmitters, not restricting the number or nature of the receivers.  For a single transmitter, we describe capacity-achieving codes for every signal-to-noise ratio. This description provides an exact measure of the disturbance of such codes on unintended receivers as well as necessary properties required from capacity achieving schemes, confirming "rules of thumb". Among the channels discussed are the Gaussian point-to-point channel, the Gaussian wiretap channel and the Gaussian broadcast channel. We continue with a more recent graphical interpretation of rate and equivocation. For two transmitters, simultaneous use creates an additional source of interference. We show how our understanding of “good” point-to-point code sequences can be used to help analyze this channel. The results resolve the "Costa", or "missing corner points" conjecture for bounded variance inputs.
Based on joint works with H. V. Poor, R. F. Schaefer and S. Shamai
Bio:  Ronit Bustin received a B.Sc. degree in electrical engineering and computer science and a M.Sc. degree in electrical engineering in 2004 and 2006, respectively, from Tel-Aviv university, Israel. She received a Ph.D. in electrical engineering in 2013 from the Technion - Israel Institute of Technology, Haifa. She is currently a postdoctoral research associate in the department of electrical engineering at Princeton University. Her research interests include multi-user information theory, secrecy constraints, Gaussian MIMO channels, estimation theory and channel coding. Ronit Bustin received the Irwin and Joan Jacobs scholarship for excellence in graduate studies and research, in January 2010. She is a recipient of the Adams fellowship from the Israel Academy of Sciences and Humanities, April 2010, and an Andrew and Erna Finci Viterbi graduate fellow in the faculty of electrical engineering at the Technion for the fall semester 2010-2011. Ronit received the Rothschild fellowship in 2013 and the women postdoctoral scholarship of Israel’s Council for Higher Education (VATAT) for her post-doctoral studies.