Topic：Energy and Spectral Efficient Communications in ARQ and HARQ Systems

Time：2013年6月24日（星期一）10:00am~11:00am

Venue：信电大楼-225学术厅

Speaker：Prof.  Jingxian Wu

                    Director, Wireless Information Network Lab

                    University of Arkansas

Abstract

Energy efficiency (EE) and spectral efficiency (SE) are two essential design metrics for wireless communication systems. Energy efficient communication reduces energy consumption and extends the battery life of wireless terminals. Spectral efficient communication aims at supporting more simultaneous with the scarce spectrum resource. However, EE and SE are often conflicting goals, featuring one of the most fundamental tradeoffs in communication system designs. In this talk, the optimum energy efficient and spectral efficient designs for automatic-repeat-request (ARQ) systems and hybrid ARQ (HARQ) systems are discussed. Three optimum designs are considered: the first scheme maximizes the EE without considering the SE; the second scheme minimizes a new metric, the energy per information bit normalized by the SE; and the third scheme maximizes the EE under the constraint of a minimum SE. The optimum designs are performed by considering a variety of parameters, such as hardware power consumption, coding rate, modulation, bit rate, number of overhead bits, and communication distance. The fundamental EE-SE tradeoff curve is analytically identified via the optimization of the third scheme, and it is shown that the optimum EE is quansiconcave in SE in a type-I ARQ system. The optimum solutions to the first two schemes are special operating points on the EE-SE tradeoff curve.

Biography

Jingxian Wu received the B.S. degree in Electrical Engineering from Beijing University of Aeronautics and Astronautics, Beijing, China, in 1998, the M.S. degree in Electrical Engineering from Tsinghua University, Beijing, China, in 2001, and the Ph.D. degree in Electrical Engineering from the University of Missouri, Columbia, in 2005. He is currently an Associate Professor with the Department of Electrical Engineering, University of Arkansas, Fayetteville. His research interests mainly focus on wireless communications and wireless networks, including high mobility wireless communications, ultra-low power communications, cooperative communications, and cross-layer optimization, etc. He is an Editor of the IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, an Associate Editor of the IEEE ACCESS, and served as an Associate Editor of the IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY from 2007 to 2011. He is also serving as the chair of the GOLD committee of IEEE Communication Society. Since 2008, Dr. Wu has received over $1.4 million U.S. dollars in research funding, from various federal or local funding agencies, such as U.S. National Science Foundation, U.S. Department of Defense, U.S. Department of Education, AT&T, etc. He is the recipient of the William D. and Margaret A. Brown Faculty Excellence Award from the University of Arkansas in 2012, and the Outstanding Service Award from the IEEE Communication Society in 2010.