Accurate time synchronization method for industrial wireless network

Abstract

The invention provides a precise time synchronization method for an industrial wireless network, relating to the industrial wireless network communication technology. Aiming at the characteristics of the industrial wireless network, such as limited energy supply, dynamic and variable network environment, the openness of the wireless network media, and the like, the invention provides a unique precise time synchronization method, wherein, a layering and grading synchronization strategy is adopted to divide the industrial wireless network according to a hierarchical structure; an MAC layer of a parent device generates beacon frames, sends the beacon frames periodically, obtains a time stamp in the processes of sending and receiving beacon frames, obtains the frequency deviation and time deviation of the equipment clock and the universal time clock by fitting the time stamps sent and received in most recently N times, compensates the local clock, realizes the time clock synchronization of a child device and the parent device; time synchronization is carried out in a grade-wise manner and finally the time synchronization of the whole network is realized. On the premise of meeting the performance requirements on the industrial wireless network, the precise time synchronization method of the invention can ensure that the whole network runs within a uniform time scale and guarantee the normal operation of the system.

Description

technical field [0001] The invention belongs to the technical field of industrial wireless network communication, in particular to a precise time synchronization method in the industrial wireless network. Background technique [0002] As a brand-new direction in the field of industrial communication technology, industrial wireless communication technology is the result of academic crossover between emerging disciplines and traditional disciplines. It has attracted widespread attention from academia and industry, and has become a hot research topic at home and abroad. one. [0003] The time synchronization problem of network system has important value both in theory and in practical application. It is the basis for guaranteeing various performances of any communication network or distribution system. The time synchronization mechanism has been widely used in traditional networks. NTP (Network Time Protocol) is a time synchronization protocol adopted by the Internet. It has t...

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Problems solved by technology

The time synchronization mechanism has been widely used in traditional networks. NTP (Network Time Protocol) is a time synchronization protocol adopted by the Internet. It has the advantages of high precision, good robustness, and easy expansion. It has been widely used, but it depends on the conditions Difficult to meet in industrial wireless networks. For example, the NTP protocol is applied in the existing wired network, the probability of network link failure is very small, the network structure of the NTP protocol is relatively stable, and the NTP protocol needs to constantly calibrate the clock frequency deviation by exchanging messages frequently The error caused by CPU usage, channel monitoring and occupation are not subject to any constraints; although RBS (Reference Broadcast Synchronization) eliminates the synchronization error introduced by the propagation delay of the sending end and improves the synchronization accuracy, this method is only suitable for small-scale The network has poor scalability and a large number of exchanged messages; TPSN (Timing-sync Protocol for Sensor Networks) introduces the NTP time synchronization method into the wireless network and achieves better accuracy, but the synchronization process is relatively complex, and the exchanged The number of messages is large, and the convergence speed is slow

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