Wireless network accurate time synchronization method

Abstract

The invention discloses a wireless network accurate time synchronization method. The method comprises the following steps: taking a clock of main equipment as a reference clock; the master device sending a message to each slave device in a broadcast or multicast form or by using an MU-MIMO technology; exchanging messages carrying time information between a master device and slave devices twice ormore, each slave device determining time offset between the slave device and the master device according to the time information carried by the messages, and adjusting local clocks according to the time offset, so that the respective clocks are in time synchronization with the master device. According to the invention, each slave device can calibrate its own clock according to the calculated clockand respectively complete time synchronization with the master device, so that time synchronization among all devices in the whole local area network is realized, and a traditional point-to-point communication mode is replaced by a broadcast or multicast mode, so that the time synchronization efficiency is improved. The timestamp is completed in the wireless device driving layer, the influence ofuncertain jitter and delay is reduced to the maximum extent without additional hardware support, and the synchronization precision is improved.

Description

technical field [0001] The invention discloses a method for precise time synchronization of a wireless network, and relates to the fields of wireless communication and industrial internet of things. Background technique [0002] Since the launch of wireless network technology, due to its advantages of low cost and easy installation, it has received extensive attention and development, and its applications in various scenarios are also increasing. However, in some fields, such as industrial control and measurement, there are extremely high requirements for the accuracy of time synchronization. Accurate time synchronization is an important basis for the effective development and operation of related systems, and the time synchronization of wireless networks Most of them use the point-to-point method for time synchronization, and the traditional wireless time synchronization method has insufficient synchronization accuracy. Therefore, in applications that have extremely high re...

AI Technical Summary

Problems solved by technology

However, in some fields, such as industrial control and measurement, there are extremely high requirements for the accuracy of time synchronization. Accurate time synchronization is an important basis for the effective development and operation of related systems, and the time synchronization of wireless networks Most of them use the point-to-point method for time synchronization, and the traditional wireless time synchronization method has insufficient synchronization accuracy. Therefore, in applications that have extremely high requirements for time synchronization accuracy, wireless networks are still not applicable, and wired networks must be used. Wireless networks cannot completely replace wired networks

[0003] At present, the time synchronization methods widely used in wired network systems include: Network Time Protocol (NTP), GPS and IEEE1588 Precision Time Protocol (PTP), etc. GPS is susceptible to environmental interference and has higher requirements for the application environment , more suitable for open areas with fewer obstacles, and cannot be used in indoor or underwater environments

And the deployment of GPS devices will also increase additional costs; NTP can only achieve millisecond-level time synchronization, and the synchronization accuracy is not high, which is difficult to meet the application requirements of those fields that need to achieve microsecond-level synchronization accuracy or more accurate; IEEE 1588 protocol provides A mechanism that can synchronize the time of each node in a distributed system with high precision. With the support of hardware time stamping, the precision can reach the nanosecond level. However, the IEEE1588 protocol is formulated for the background of wired networks. Currently, hardware that supports IEEE1588 hardware time stamping is available on the market. The equipment is concentrated in the Ethernet network equipment, and the wireless network equipment does not yet have this kind of hardware support, so it cannot be directly applied to the wireless network

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