2018年海洋信息论坛第17期
报告题目：Time reversal based frequency-domain equalization for underwater acoustic single-carrier transmissions
报告人：Dr. Aijun Song
时间：
地点：水声楼315会议室
报告人简介：
Dr. Aijun Song received his Ph.D. degree in the Department of Electrical Engineering, University of Delaware, Newark, Delaware in 2005. He is currently an Assistant Professor in the Department of Electrical and Computer Engineering, University of Alabama, Tuscaloosa, AL, USA. From 2005 to 2008, he was a postdoctoral research associate at the College of Earth, Ocean and Environment, University of Delaware, Newark, DE. During this period, he was also an Office of Naval Research (ONR) postdoctoral fellow, supported by the special research award in the ONR Ocean Acoustics program. He was an Assistant Research Professor at the University of Delaware from 2008 to 2014 and an Associate Research Professor from 2014 to 2015. He was the General Co-Chair of 2018 NSF Workshop on Wireless Communications and Networking. His current research interests include digital communications and signal processing techniques for radio frequency and underwater acoustic channels, ocean acoustics, sensor networks, ocean monitoring and exploration.
报告摘要：
Time reversal processing generates a time-focused signal, after combining dispersive reception from a hydrophone array in the underwater acoustic channel. Because of this property, the time reversal method has been studied as a preprocessing scheme to support decision feedback equalization for underwater acoustic communications. Orthogonal frequency division multiplexing has also been combined with time reversal processing to improve spectral efficiency, as the equivalent compact channel impulse response allows short prefixes in the acoustic channel. We show that time reversal processing can be used to facilitate prefix-free frequency domain equalization. Traditional frequency domain equalization schemes rely on the use of periodic prefixes, which bring a loss of spectral efficiency in the already-bandlimited underwater channel. The core idea is to use time reversal pre-processing to generate a delta-like equivalent impulse response to facilitate robust reconstruction of prefixes at the receiver for prefix-free single-carrier transmissions. The resultant receiver not only improves the spectral efficiency, but also supports communications over channels of variable fluctuation rates. The effectiveness of the receiver has been tested using the field measurements from the Gulf of Mexico in August 2016. In this talk, I will present the receiver design and algorithm validation based on the experimental work.