Princeton University

School of Engineering & Applied Science

Information-theoretic perspective on massive multiple-access

Yury Polyanskiy, Massachusetts Institute of Technology
B205 Engineering Quadrangle
Monday, November 20, 2017 - 4:30pm

The key expected innovation of the next generation of radio-access networks is their ability to service orders of magnitude more active devices (the "Internet-of-Things''). Current networks were designed focusing on the regime of relatively few simultaneously active users. The typical (and information-theoretically optimal) solution is to orthogonalize degrees of freedom of different users via a centralized resource allocation. This solution requires significant control-layer overhead, and, under machine-type communication, incurs unacceptable penalty on latency and energy efficiency.

To address the challenge, we postulate three modifications to the standard (Ahslwede-Liao) MAC problem: probability of error is defined per user instead of globally for all users, the number of users is proportional to blocklength and users are required to use exactly the same codebook. In this work, I will overview recent results for this new formulation.  A key conclusion is discovery of an orders-of-magnitude gap between the energy-per-bit achievable via (newly derived) random coding bounds and various popular practical solutions.
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.