Title: On the Minimum Energy of Sending Correlated Sources over the Gaussian MAC

Speaker: Professor Zixiang Xiong (熊子祥教授，ECE, Texas A&M University, IEEE Fellow)

Time: 2PM, Tuesday, 9 April 2013

Venue: 电院5号楼406室

We investigate the minimum energy of transmitting correlated sources over the Gaussian multiple-access channel (MAC). Compared to other works on joint source-channel coding, we consider the fundamental problem of the minimum transmission energy, where the source and channel bandwidths are not naturally matched. Different models of correlated sources are studied. We first treat lossy transmission of Gaussian sources, including multiterminal sources and CEO sources. We then consider lossless transmission of correlated binary sources. In all cases, we lower bound the minimum energy using a cut-set argument that couples transmission energy and the distortions for the Gaussian cases (or source entropy for the discrete case). For achievability, separate source-channel coding and uncoded transmission are first considered, with asymptotic properties provided in the high- and low-energy regime, respectively. A hybrid digital/analog scheme is then proposed to achieve the best known energy performance. Finally we show numerically that for all positive symmetric Gaussian sources, the maximum gap between our upper and lower bounds is 2.75 dB.

Zixiang Xiong received the Ph.D. degree in Electrical Engineering in 1996 from the University of Illinois at Urbana-Champaign. From 1995 to 1997, he was with Princeton University, first as a visiting student, then as a research associate. From 1997 to 1999, he was with the University of Hawaii. Since 1999, he has been with the Department of Electrical and Computer Engineering at Texas A&M University, where he is a professor. During Spring 2010, he spent his sabbatical leave at Stanford University.

He received an NSF Career Award in 1999, an ARO Young Investigator Award in 2000 and an ONR Young Investigator Award in 2001. He also received the 2006 IEEE Signal Processing Magazine best paper award. He served as associate editor for the IEEE Trans. on Circuits and Systems for Video Technology (1999-2005), the IEEE Trans. on Image Processing (2002-2005), the IEEE Trans. on Signal Processing (2002-2006), and the IEEE Trans. on Systems, Man, and Cybernetics (part B) (2005-2009). He is currently an associate editor for the IEEE Trans. on Communications. He is a fellow of the IEEE.