EEE Series Academic Seminar: Energy-Efficient Time Synchronisation Achieving Nanosecond Accuracy in Wireless Networks



Dr Kyeong Soo (Joseph) Kim
Associate Professor, Department of Electrical and Electronic Engineering, XJTLU


Dr Yanyan Wu
Associate Professor, Department of Electrical and Electronic Engineering, XJTLU

Speaker's Bio

Kyeong Soo (Joseph) Kim received B.S., M.S., and Ph.D. degrees in Electronics Engineering from Seoul National University, Seoul, Korea, in 1989, 1991, and 1995, respectively. From 1996 to 1997, he was engaged in the development of multi-channel asynchronous transfer mode
(ATM) switching systems as a Post-Doc researcher at Washington University in St. Louis, Missouri, where he also taught undergraduate and graduate students as an Instructor of Washington University in St. Louis and Adjunct professor of University Missouri - St. Louis.

From 1997 to 2000, he worked with the passive optical network (PON) Systems R&D organization of Lucent Technologies and was involved with development of ATM-PON systems, which won the 1999 Bell Labs President's Silver Award.

From Jan. 2001 to Jul. 2007, he was with STMicroelectronics, working as a Principal Engineer, and represented STMicroelectronics in various standard bodies, including FSAN, ITU-T, and IEEE 802.11/16 working groups; from Jan. 2001 to Aug. 2006, he also took the position of STMicroelectronics Researcher-in-Residence at the Stanford Networking Research Center (SNRC) and worked on "Optical Internet" and "Next-Generation Access Networks" projects together with students and faculties at Stanford University.

From Aug. 2007 to Jun. 2014, he worked at the College of Engineering, Swansea University, Wales, U.K., as Associate Professor in Networking, where he led Hybrid Networking Research Laboratory (HNRL) and carried out research in next-generation optical access (NGOA) and hybrid optical-wireless networks.

Since Jul. 2014, he has been working at the Department of Electrical and Electronic Engineering (EEE), Xi'an Jiaotong-Liverpool University (XJTLU), Suzhou, China, as Associate Professor. Please visit Dr Kim’s personal home page for more details and up-to date research activities.


As mobile networks continue to evolve to 5G providing much higher speed & far greater coverage and wireless sensor networks penetrate even deeper into every aspect of our daily lives while being integrated into the Internet of Things, we see that more and more tasks require higher timing synchronization accuracies than usual (i.e., << 1µs), including fine-grained localization, tracking & navigation for autonomous driving, coordinated jamming, distributed beam forming, and distributed surveillance & sensing in civil and military domains. In this talk, we present an energy-efficient wireless time synchronization scheme that can achieve nanosecond accuracy. Taking into account the asymmetry between a head node - i.e., equipped with a powerful processor and supplied power from outlet - and sensor nodes - i.e., limited in processing and battery-powered - in a typical wireless sensor network, we base the proposed time synchronization scheme on asynchronous source clock frequency recovery and reverse two-way message exchanges combined with measurement data report messages in order to minimize the number of message transmissions from sensor nodes while achieving nanosecond time synchronization accuracy through propagation delay compensation. We carry out the performance analysis of the estimation of both measurement time and clock frequency with lower bounds.
Simulation results verify that the proposed scheme outperforms the schemes based on conventional two-way message exchanges with and without clock frequency recovery in terms of the accuracy of measurement time estimation and the number of message transmissions & receptions at sensor nodes as an indirect measure of energy efficiency.