Title: Millimeter Wave MIMO with Lens Antenna Array: A New Path Division Multiplexing Paradigm

Abstract: Millimeter wave (mmWave) communication over the largely unused mmWave spectrum is a promising technology for 5G. To compensate for the severe path loss, mmWave systems usually require large antenna arrays at both the transmitter and receiver to achieve enormous beamforming gains. However, the high hardware and power consumption cost due to the large number of radio frequency (RF) chains required renders the traditional beamforming method based on full array processing impractical for mmWave MIMO systems. In this talk, we will start with a brief introduction on the main existing techniques for mmWave MIMO communications, including antenna selection, analog beamforming and hybrid analog/digital precoding, single-carrier (SC) and OFDM based MIMO transmission. Then a new lens-antenna-array enabled mmWave MIMO system will be introduced, which achieves the large MIMO gain but with only limited number of RF chains. The array response of the proposed lens antenna MIMO system will be presented, followed by a novel MIMO communication technique called path division multiplexing, which jointly exploits the multi-path sparsity of mmWave channels and the energy-focusing property of lens antenna arrays to achieve low-complexity and yet high-performance MIMO transmissions in both TDD and FDD modes, as well as under both flat- and frequency-selective-fading channels. Numerical results show significant (over 10x) throughput gains of the proposed lens MIMO system against the conventional MIMO arrays with limited RF chains.

Biography:Dr. Rui Zhang received the B.Eng. (First-Class Hons.) and M.Eng. degrees from the National University of Singapore in 2000 and 2001, respectively, and the Ph.D. degree from the Stanford University, Stanford, CA USA, in 2007, all in electrical engineering. From 2007 to 2009, he worked at the Institute for Infocomm Research, A*STAR, Singapore, where he now holds a Scientist joint appointment. Since 2010, he has joined the Department of Electrical and Computer Engineering of the National University of Singapore where he is now an Associate Professor. His current research interests include energy-efficient and energy-harvesting-enabled wireless communications, wireless information and power transfer, MIMO, cognitive radio, UAV-assisted communications, wireless surveillance, and optimization methods. He has published over 250 papers, which have been cited more than 1,2000 times. He was the recipient of the 6th IEEE Communications Society Asia-Pacific Region Best Young Researcher Award in 2011, and the Young Researcher Award of the National University of Singapore in 2015. He was the co-recipient of the IEEE Marconi Prize Paper Award in Wireless Communications in 2015. He has served for over 30 international conferences as TPC Co-Chair or Organizing Committee Member, and as the guest editor for several special issues in IEEE journals. He has been an elected member of the IEEE Signal Processing Society SPCOM and SAM Technical Committees, and the Vice Chair of the IEEE Communications Society Asia-Pacific Board Technical Affairs Committee. He is the primary voting representative of IEEE Signal Processing Society in the IEEE Technical Committee on RFID (CRFID). He is an editor for the IEEE Transactions on Wireless Communications, the IEEE Transactions on Signal Processing, and the IEEE Journal on Selected Areas in Communications (Green Communications and Networking Series). He has been listed as a Thomson Reuters Highly Cited Researcher in 2015.