Embedded Synchronizing Internet Clocks (E-SIC) without dedicated hardware
DOI:
https://doi.org/10.37537/rev.elektron.5.2.137.2021Keywords:
clock, synchronization, WI-FI, IoTAbstract
E-SIC is an algorithm designed to synchronize the clocks of embedded controllers through a Local Area Network (LAN) using 802.11 (WI-FI) technology. It’s based on the SIC algorithm that synchronizes frequency between the clocks by taking advantage of the symmetry of the networks round trip time. By considering an historic window of measurements and the usage of the mode as an estimation tool, the E-SIC algorithm has achieved absolute clock sync between two devices with a higher accuracy than two milliseconds without the requirement of extra hardware.Downloads
References
H. Kopetz and W. Ochsenreiter, “Clock Synchronization in Distributed Real-Time Systems,” IEEE Transactions on Computers, vol. C-36, no. 8, pp. 933–940, 1987.
M. Mock, R. Frings, E. Nett, and S. Trikaliotis, “Continuous clock synchronization in wireless real-time applications,” in Proceedings 19th IEEE Symposium on Reliable Distributed Systems SRDS-2000, 2000, pp. 125–132.
Masterclock, “GPS vs. GNSS: Understanding PNT Satellite Systems,” Jan 2019. [Online]. Available: https://www.masterclock.com/company/masterclock-inc-blog/gps-vs-gnss
T. Yokoyama, A. Matsubara, and M. Yoo, “A real-time operating system with gnss-based tick synchronization,” in 2015 IEEE 3rd International Conference on Cyber-Physical Systems, Networks, and Applications, 2015, pp. 19–24.
J. Martin, J. Burbank, W. Kasch, and P. D. L. Mills, “Network Time Protocol Version 4: Protocol and Algorithms Specification,” RFC 5905, Jun. 2010. [Online]. Available: https://rfc-editor.org/rfc/rfc5905.txt
“IEEE standard for a precision clock synchronization protocol for networked measurement and control systems,” IEEE Std 1588-2019 (Revision ofIEEE Std 1588-2008), pp. 1–499, 2020.
M. Bansal and A. Gupta, “Out-degree based clock synchronization in wireless networks using precision time protocol,” in 2018 IEEE International Conference on Advanced Networks and Telecommunications Systems (ANTS). IEEE, 2018, pp. 1–6.
R. Holler, T. Sauter, and N. Kero, “Embedded synutc and ieee 1588 clock synchronization for industrial ethernet,” in EFTA 2003. 2003 IEEE Conference on Emerging Technologies and Factory Automation. Proceedings (Cat. No.03TH8696), vol. 1, 2003, pp. 422–426 vol.1.
L. Li, B. Li, and H. Wang, “Clock synchronization of wireless distributed system based on ieee 1588,” in 2010 International Conference on Cyber-Enabled Distributed Computing and Knowledge Discovery, 2010, pp. 205–209.
J. I. Alvarez-Hamelin, D. Samaniego, A. A. Ortega, and R. Geib, “Synchronizing Internet Clock frequency protocol (sic),” Internet Engineering Task Force, Internet-Draft draft-alavarez-hamelin-tictoc-sic-06, Oct. 2020, work in Progress. [Online]. Available: https: //datatracker.ietf.org/doc/html/draft-alavarez-hamelin-tictoc-sic-06
D. Veitch, J. Ridoux, and S. B. Korada, “Robust synchronization of absolute and difference clocks over networks,” IEEE/ACM Transactions on Networking, vol. 17, no. 2, pp. 417–430, 2009.
D. R. Bickel and R. Frühwirth, “On a fast, robust estimator of the mode: Comparisons to other robust estimators with applications,” Computational Statistics & Data Analysis, vol. 50, no. 12, pp. 3500–3530, 2006. [Online]. Available: https://www.sciencedirect.com/science/article/pii/S0167947305001581.
ESP32 Series Datasheet, Espressif Systems, 2021, ver. 3.6.
T. S. S. O. ITU, “Definitions and terminology for synchronization in packet networks (Recommendation ITU-T G.8260),” August 2015.
S. Bregni, “Measurement of maximum time interval error for telecommunications clock stability characterization,” IEEE transactions on instrumentation and measurement, vol. 45, no. 5, pp. 900–906, 1996.
Downloads
Published
Issue
Section
License
The authors who publish in this journal agree with terms established in the license Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)