Wednesday, February 20, 2019
4:00 pm

EE Systems Seminar

Information theory of multiple-access channels with many users
Yury Polyanskiy, Associate Professor, Electrical Engineering and Computer Science , Massachusetts Institute of Technology

ABSTRACT       The radio networks' paradigm is gradually shifting from servicing a few simultaneously-active trafic-hungry (human) users to hundreds of thousands of low-rate (machine) users. In this talk we consider new information-theoretic (IT) questions arising from formalizing this problem. A surprising discovery is existence of coded-access schemes that are able to perfectly reject multi-user interference, so that increasing the density of users (without increasing space-time-frequency resources!) does not lead to any deterioration of service. Practically important is that decades-old multiple-access architectures (TDMA/FDMA, ALOHA, CDMA) are far from attaining this effect.

Theoretically, we discover that this transition in IT parallels the one in statistics when dimensionality of feature (regressor) vectors has dramatically increased and sparsity considerations surfaced.
Similarly, we will find that traditional IT tools need to be augmented with methods such as Gaussian widths and Gordon's lemma. In fact our methods also imply new results on sparse binary regression, for which we establish rigorous bounds that closely match replica-method predictions from statistical physics.

BIO                    Yury Polyanskiy is an Associate Professor of Electrical Engineering and Computer Science and a member of LIDS at MIT. Yury received M.S. degree in applied mathematics and physics from the Moscow Institute of Physics and Technology, Moscow, Russia in 2005 and Ph.D. degree in electrical engineering from Princeton University, Princeton, NJ in 2010. Currently, his research focuses on basic questions in information theory, error-correcting codes, wireless communication and fault-tolerant and defect-tolerant circuits.
Dr. Polyanskiy won the 2013 NSF CAREER award and 2011 IEEE Information Theory Society Paper Award.
 

      

Contact Liliana Chavarria lchavarr@caltech.edu at 626-395-4715
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