Topic: Quaternion-Valued Signal Processing for Dual-Polarised Antenna Array Communication Systems
Speaker: Wei Liu, Ph.D., University of Sheffield
Time: August 6, at 14:00
Venue: F706, New Main Building
A dual-polarised antenna array such as a crossed-dipole array can exploit the polarisation information of the signal and increase the capacity of the communiation system. The four-dimensional signal involved in the dual-polarised array can be represented by a quaternion. Although quaternion-valued wireless communication systems have been studied in the past and progress has been made in this promising area, a crucial missing link is lack of effective and efficient quaternion-valued signal processing algorithms for channel equalization and beamforming. With recent developments in quaternion-valued signal processing, in this work, we fill the gap and solve the problem by studying two quaternion-valued adaptive algorithms: one is the reference signal based quaternion-valued least mean square (QLMS) algorithm and the other one is the quaternion-valued constant modulus algorithm (QCMA). The quaternion-valued Wiener solution for possible block-based calculation is also derived. Furthermore, we study a specific adaptive beamforming problem where the direction of the quaternion-valued impinging signal of interest is known and develop an efficient beamforming algorithm to receive the four components of the signal simultaneously while suppressing interfering signals from other directions.
Biography of the Speaker:
Dr. Wei Liu received his B.Sc. in 1996 and L.L.B. in 1997, both from Peking University, China, M.Phil. from University of Hong Kong, in 2001, and Ph.D. in 2003 from the School of Electronics and Computer Science, University of Southampton, UK. He later worked as a postdoc at Imperial College London. Since September 2005, he has been with the Department of Electronic and Electrical Engineering, University of Sheffield, UK, first as a lecturer, and then a senior lecturer. His research interests are in sensor array signal processing, blind signal processing, multivariate signal processing and their various applications in wireless communications, radar, sonar, satellite navigation, human computer interface, distributed autonomous systems, and renewable energy exploitation, etc. He has now published 250 journal and conference papers, three book chapters, and a research monograph about wideband beamforming (“Wideband Beamforming: Concepts and Techniques”, John Wiley & Sons, March 2010). Another book about low-cost smart antennas will appear in early 2019 (“Low-cost Smart Antennas”, ISBN: 978-1-119-42277-8, Wiley-IEEE Press). He is a senior member of IEEE, an elected member of the Digital Signal Processing Technical Committee of the IEEE Circuits and Systems Society and the Sensor Array and Multichannel Signal Processing Technical Committee of the IEEE SignalProcessing Society, currently an associate editor for IEEE Trans. Signal Processing and IEEE Access, and an editorial board member of the journal Frontiers of Information Technology & Electronic Engineering. He is also the general co-chair for the 2018 IEEE Sensor Array and Multichannel Signal Processing Workshop, 8-11 July, Sheffield, UK.