[Colloq] colloquium: Polar Codes for Multiple Access Channels

[Francoise Niang]

Host: Guevara Noubir 

Time: 12/11 Wed, 10:30AM
Location: 366WVH

Speaker
Title: Polar Codes for Multiple Access Channels

Abstract:

Achieving the fundamental capacity limits of communication channels with 
low complexity coding schemes has been a major challenge for over 60 
years. Recently, a revolutionary coding construction, called Polar 
coding, has been shown to provably achieve the "symmetric capacity" of 
binary-input, memoryless single-user channels. The underlying principle 
of the technique is to convert repeated uses of a given single-user 
channel to single uses of a set of extremal channels, whereby almost 
every channel in the set is either almost perfect, or almost useless. 
The latter phenomenon is referred to as polarization.

Whereas a number of practical coding constructions (e.g. Turbo codes and 
Low Density Parity Check codes) can empirically approach the capacity of 
single-user communication channels, there is still a lack of good 
practical coding schemes for multi-user communication channels. In this 
talk, we extend the polar coding method to two-user multiple-access 
communication channels. We have shown that if the two users use the 
channel combining and splitting construction, the resulting 
multiple-access channels will polarize to one of five possible 
extremals, on each of which uncoded transmission is optimal. Our coding 
technique can achieve some of the optimal transmission rate pairs 
obtained with uniformly distributed inputs. The encoding and decoding 
complexity of the code is O(n log n) with n being the block length, and 
the block error probability is roughly O(2^{-\sqrt{n}}). Our 
construction is one of the first low-complexity coding schemes which 
have been proved to achieve capacity in multi-user communication networks.

Joint work with Eren Sasoglu (UC Berkeley) and Emre Telatar (EPFL)

Biography:

Edmund Yeh received his B.S. in Electrical Engineering with Distinction 
from Stanford University in 1994, his M.Phil in Engineering from the 
University of Cambridge in 1995, and his Ph.D. in Electrical Engineering 
and Computer Science from MIT under Professor Robert Gallager in 2001. 
Since July 2011, he has been Associate Professor of Electrical and 
Computer Engineering at Northeastern University. Previously, he was 
Assistant and Associate Professor of Electrical Engineering, Computer 
Science, and Statistics at Yale University.  He has held visiting 
positions at MIT, Princeton, University of California at Berkeley, Swiss 
Federal Institute of Technology Lausanne (EPFL), and Technical 
University of Munich.

Professor Yeh is the recipient of the Alexander von Humboldt Research 
Fellowship, the Army Research Office Young Investigator Award, the 
Winston Churchill Scholarship, the National Science Foundation and 
Office of Naval Research Graduate Fellowships, the Barry M. Goldwater 
Scholarship, the Frederick Emmons Terman Engineering Scholastic Award, 
and the President's Award for Academic Excellence (Stanford University). 
He is a Senior Member of the IEEE, a member of Phi Beta Kappa and Tau 
Beta Pi. He received the Best Paper Award at the IEEE International 
Conference on Ubiquitous and Future Networks (ICUFN), Phuket, Thailand, 
July 2012.  Professor Yeh serves as the Secretary of the Board of 
Governors of the IEEE Information Theory Society.