Zixiang Xiong

On the energy-delay tradeoff in lossy network communications

This work investigates the energy-delay tradeoff in real-time network communication systems with ARQ, where energy is measured by power and energy per bit, respectively. We consider the lossy communication case with a finite buffer size, where each block is allowed to be retransmitted under a time constraint. We apply finite blocklength results of channel coding into our system. By adaptively optimizing the blocklength, coding rate, power allocation, and maximum number of retransmissions according to the queue state, we algorithmically achieve the optimal energy-delay tradeoff. We also lower and upper bound the optimal energy-delay function in order to study its asymptotic behavior as the delay and buffer size go to infinity, showing consistency with existing result. That is: the energy per bit approaches the minimum of -1.59 dB as the delay goes to infinity and power approaches zero. We observe that the power increases very rapidly when delay moves away from infinity, meaning that it is very hard to achieve the -1.59 dB limit in practice.

Biography: Zixiang Xiong received his Ph.D. degree in electrical engineering from the University of Illinois at Urbana-Champaign in 1996. He is currently a professor in the Department of Electrical and Computer Engineering at Texas A&M University. His main research interest lies in signal and information processing over networks. Dr. Xiong received a National Science Foundation Career Award in 1999, an Army Research Office Young Investigator Award in 2000, and an Office of Naval Research Young Investigator Award in 2001. He also received the 2006 IEEE SIGNAL PROCESSING MAGAZINE Best Paper Award. He served as an Associate Editor for five IEEE Transactions. He was the Publications Chair of ICASSP 2007, the Technical Program Committee Co-Chair of ITW 2007, the Tutorial Chair of ISIT 2010, and the Awards Chair of Globecom 2014. He is a fellow of the IEEE.