| Summary: | 碩士 === 國立臺灣大學 === 電機工程學研究所 === 102 === With the progress of the times, the dependency on desktop computers by people now is gradually shifted to mobile devices. Smart phones and tablet computers more and more popular. Mobiles devices bring a new type of life to people. People can use mobile devices to communicate to other people or other smart devices, also people can interact with smart mobile devices. Aglobal standard time for mobile devices to follow bacomes a basic issue. So a high precision time synchronization method is needed. In this paper, we design and implement a clock synchronization system for mobile devices. It is based on IEEE1588 precise time protocol.
The IEEE1588 protocol defines the information and rules for precision time protocol (PTP). It can measure the clock offset between two devices by the exchange of time network packets.
We build a virtual clock so that the operating system of mobile devices will not be invaded. IEEE1588 precision time protocol, clock state estimator and controller are used to implement clock synchronization system. First we use IEEE1588 precision time protocol to measure the clock offset between devices. Second we use the Kalman filter to estimate the clock state. Also, the parameters of the Kalman filter are adjusted by clock noise estimators. And third we adjust the clock frequency and control the clock phase by a proportion-integral controller. Experimental results show that our system provides good clock synchronization performances for mobile devices
|
|---|
