Events Calendar

MHI Distinguished Visitor Talk

Speaker: Prof. K.J. Ray Liu, University of Maryland

Talk Title: Why Time-Reversal for Future 5G Wireless?

Abstract: Time reversal is a fundamental physical phenomenon that takes advantage of unavoidable but rich multi-paths in radio propagation to create the spatial-temporal resonance effect, the so-called focusing effect. One can image that the larger the transmission power, the more observable multipaths. When the power is fixed, so does the maximum number of observable multipaths. Since radio waves travel at the speed of light, for one to see the multipath profile in detail, it needs high resolution in time, which implies very broad bandwidth in frequency. The larger the bandwidth, the better the time resolution, and therefore the more multipaths can be revealed. In essence, multipaths are naturally existing 'degrees of freedom' ready to be harvested via power and bandwidth. In a real environment, especially indoors, depending on the structure of the buildings, the number of observable multipaths can one observe is around 15-30 significant multipaths with 150 MHz bandwidth - the entire ISM band at 5.8 GHz. Such a large number of degrees of freedom, existing in nature, can be harvested to enable engineering applications. In this talk, we will argue that time-reversal is an ideal platform for future 5G wireless because it realizes the massive multipath effect by using a single antenna and has low complexity as the environment is serving as the computer. It is highly secure and energy efficient, scalable for extreme network densification, and ideal for cloud-based radio networks. It also offers very simply but high resolution for indoor positioning systems, an essential property for Internet of Things applications. Time-reversal meets all the demands one can envision for future 5G wireless!

Biography: Dr. K. J. Ray Liu was named a Distinguished Scholar-Teacher of University of Maryland, College Park, in 2007, where he is Christine Kim Eminent Professor of Information Technology. He leads the Maryland Signals and Information Group conducting research encompassing broad areas of information and communications technology with recent focus on future wireless technologies, network science, and information forensics and security. Dr. Liu was a recipient of the 2016 IEEE Leon K. Kirchmayer Technical Field Award on graduate teaching and mentoring, IEEE Signal Processing Society 2014 Society Award, IEEE Signal Processing Society 2009 Technical Achievement Award, and various best paper awards. Recognized by Thomson Reuters as a Highly Cited Researcher, he is a Fellow of IEEE and AAAS. Dr. Liu is a member of IEEE Board of Director. He was President of IEEE Signal Processing Society, where he has served as Vice President -“ Publications and the Editor-in-Chief of IEEE Signal Processing Magazine. He also received teaching and research recognitions from University of Maryland including university-level Invention of the Year Award (three times); and college-level Poole and Kent Senior Faculty Teaching Award, Outstanding Faculty Research Award, and Outstanding Faculty Service Award, all from A. James Clark School of Engineering (one award each per year from the entire college).

Host: Prof. Shrikanth Narayanan & Prof. C.-C. Jay Kuo

Location: Hughes Aircraft Electrical Engineering Center (EEB) - 132

Audiences: Everyone Is Invited

Contact: Tanya Acevedo-Lam/EE-Systems