Gary Proportional Integral Controller for Precision Time Synchronization

T.-K. Wang, P.-H. Lee, and F.-R. Chang (Taiwan)


IEEE1588, PTP, PTPd, Gray PI, GPI


IEEE1588 standard is a precision time synchronization protocol (PTP). It is designed to synchronize real-time clocks in the nodes of a distributed network system. Within a subnet, the PTP system is expected to achieve the synchronization accuracy in sub-microsecond range. The unit of clock servo plays important roles in the PTP system. It is usually implemented by traditional proportional integral (PI) controller. In order to improve the performance of the traditional PI controller, this study adopts the gray theory. The drift of the time offset from the master clock is predicted by gray algorithms. Accordingly, the gray PI controller reduces the required time to reach steady state. Experimental results show that the performance of the gray PI controller is better than that of the traditional one in the sense of the transient time being significantly shortened.

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