TY - JOUR
T1 - Feedback-based clock synchronization in wireless sensor networks
T2 - A control theoretic approach
AU - Chen, Jiming
AU - Yu, Qing
AU - Zhang, Yan
AU - Chen, Hsiao Hwa
AU - Sun, Youxian
N1 - Funding Information:
Manuscript received November 9, 2009; revised February 27, 2010; accepted April 23, 2010. Date of publication May 6, 2010; date of current version July 16, 2010. This work was supported in part by the National Natural Science Foundation of China (NSFC)–Guangdong Province Joint Project–under Grant U0735003, by NSFC under Grant 60736021 and Grant 60974122, by the China 863 High-Tech Project under Grant 2007AA041201, by the 111 Project under Grant B07031, by the Fundamental Research Funds for the Central Universities under Grant 2009QNA5007, and by the Taiwan National Science Council under Grant NSC98-2219-E-006-011. The review of this paper was coordinated by Prof. O. B. Akan.
PY - 2010/7
Y1 - 2010/7
N2 - Most wireless sensor networks (WSNs) employ a sleep clock to enable sensor onoff mode to save energy. Since the sleep clock usually works at a relatively low frequency, it is important to correct the long-term synchronization error caused by instability and nonlinearity. In this paper, the time synchronization issue in a WSN is formulated as a closed-loop control problem. Using the proportionalintegral (PI) control principle, we propose a feedback-based synchronization (FBS) scheme to compensate the clock drift caused by both internal perturbation and external disturbance. Synchronization accuracy and FBS dynamics are analyzed in terms of response time and overshoot. We also derive a formula to determine the controller parameters for different synchronization accuracy and response-time requirements. Extensive experiments have been conducted to evaluate this synchronization scheme. The results indicate that FBS is much more robust than the delay measurement time-synchronization (DMTS) protocol in different synchronization durations and sensor node configurations. It is shown that FBS achieves almost the same accuracy as the flooding time-synchronization protocol (FTSP) when synchronization period $P$ is less than 60 s, and it outperforms FTSP when $P$ is longer than 60 s. Furthermore, the experimental results reveal that FBS's response to an external disturbance is faster than that of FTSP in one- or two-hop WSN scenarios. In addition, FBS consumes fewer resources than FTSP.
AB - Most wireless sensor networks (WSNs) employ a sleep clock to enable sensor onoff mode to save energy. Since the sleep clock usually works at a relatively low frequency, it is important to correct the long-term synchronization error caused by instability and nonlinearity. In this paper, the time synchronization issue in a WSN is formulated as a closed-loop control problem. Using the proportionalintegral (PI) control principle, we propose a feedback-based synchronization (FBS) scheme to compensate the clock drift caused by both internal perturbation and external disturbance. Synchronization accuracy and FBS dynamics are analyzed in terms of response time and overshoot. We also derive a formula to determine the controller parameters for different synchronization accuracy and response-time requirements. Extensive experiments have been conducted to evaluate this synchronization scheme. The results indicate that FBS is much more robust than the delay measurement time-synchronization (DMTS) protocol in different synchronization durations and sensor node configurations. It is shown that FBS achieves almost the same accuracy as the flooding time-synchronization protocol (FTSP) when synchronization period $P$ is less than 60 s, and it outperforms FTSP when $P$ is longer than 60 s. Furthermore, the experimental results reveal that FBS's response to an external disturbance is faster than that of FTSP in one- or two-hop WSN scenarios. In addition, FBS consumes fewer resources than FTSP.
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U2 - 10.1109/TVT.2010.2049869
DO - 10.1109/TVT.2010.2049869
M3 - Article
AN - SCOPUS:77954597619
SN - 0018-9545
VL - 59
SP - 2963
EP - 2973
JO - IEEE Transactions on Vehicular Technology
JF - IEEE Transactions on Vehicular Technology
IS - 6
M1 - 5460894
ER -