CN111555834B - Clock synchronization method and system of wireless network based on IEEE1588 protocol - Google Patents
Clock synchronization method and system of wireless network based on IEEE1588 protocol Download PDFInfo
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Abstract
The embodiment of the invention provides a clock synchronization method and a system of a wireless network based on an IEEE1588 protocol, wherein a first time stamp, a second time stamp, a third time stamp and a fourth time stamp are respectively obtained by a second device of a clock synchronization system; the first timestamp is the time when the synchronous message leaves the network layer of the first device and reaches the first wireless communication module; the second timestamp is the time before the synchronous message leaves the second wireless communication module and reaches the network layer of the second device; acquiring time deviation between a slave clock and a master clock and network time delay between second equipment and first equipment based on the first time stamp, the second time stamp, the third time stamp and the fourth time stamp; and inputting the time deviation and the network delay into a preset deviation rectifying formula to obtain deviation rectifying time, and adjusting the slave clock by utilizing the deviation rectifying time. The scheme can improve the precision of clock synchronization.
Description
Technical Field
The invention relates to the technical field of clock synchronization, in particular to a clock synchronization method and a clock synchronization system of a wireless network based on an IEEE1588 protocol.
Background
With the development of technology, a measurement system or a control system is often in a distributed system structure, and devices in the system communicate through a network, which is equivalent to a distributed network system. In order to ensure the cooperative operation of each device in the system, the clock synchronization of each device needs to be realized. For this reason, clock synchronization of each device in the distributed network system can be realized based on IEEE1588 standard (precision clock synchronization protocol standard of network measurement and control system). The clock synchronization realized based on the protocol can be summarized as follows: selecting a clock with the best clock performance parameters as a master clock, using equipment where the master clock is located as first equipment, using equipment except the first equipment in the system as second equipment, and using the clock of the second equipment as a slave clock; in the communication process of the second device based on the delay request response mechanism, the time deviation between the slave clock and the master clock of the second device and the network delay between the second device and the first device are obtained by the timestamp of each message, the obtained time deviation and the obtained network delay are input into a preset deviation correction formula to obtain deviation correction time, and then the slave clock of the second device is adjusted by the deviation correction time to realize clock synchronization between the slave clock and the master clock.
The communication process of the delay request response mechanism is the communication between the first equipment and the second equipment aiming at the synchronous message and the delay request message; the time stamp of each message comprises: the sending timestamp of the synchronous message, the receiving timestamp of the synchronous message, the sending timestamp of the delay request message and the receiving timestamp of the delay request message. In a specific application, because the distributed measurement and/or control system uses a wireless Network to implement communication between devices, the timestamp of each message is often recorded according to NTP (Network Time Protocol). Specifically, for a packet related to the delay request response mechanism, when the packet reaches an application layer of the device, the current time of the application layer is recorded as a timestamp of the packet. However, there are also transport and network layers below the application layer of the device, and the wireless network itself has a data link layer and a physical layer. In the communication process of the delay request response mechanism, a message also occupies a certain time length after passing through layers except an application layer, and delay exists. Therefore, if the current time of the application layer is directly recorded as the time stamp for message transmission or reception, there is a difference between the time stamp and the actual transmission or reception time due to the time delay of the layer other than the application layer, which results in that the precision of clock synchronization realized by using the time stamp can only reach the millisecond level, and the precision of clock synchronization is low.
Disclosure of Invention
The embodiment of the invention aims to provide a clock synchronization method and a clock synchronization system of a wireless network based on an IEEE1588 protocol, so as to achieve the effect of improving the clock synchronization precision of the wireless network based on the IEEE1588 protocol. The specific technical scheme is as follows:
in a first aspect, an embodiment of the present invention provides a clock synchronization method for a wireless network based on an IEEE1588 protocol, which is applied to a second device of a clock synchronization system, where the clock synchronization system further includes a first device; wherein, the clock of the first device is a master clock, the clock of the second device is a slave clock, the wireless communication between the first device and the second device is realized by a first wireless communication module corresponding to the first device and a second wireless communication module corresponding to the second device, the method comprises:
respectively acquiring a first time stamp, a second time stamp, a third time stamp and a fourth time stamp; the first timestamp is the time when the synchronization message leaves the network layer of the first device and reaches the first wireless communication module; the second timestamp is a time before the synchronization packet leaves the second wireless communication module and reaches a network layer of the second device; the third timestamp is a time when the delay request message leaves the network layer of the second device and reaches the second wireless communication module; the fourth timestamp is a time before the delay request packet leaves the first wireless communication module and reaches a network layer of the first device;
acquiring a time offset between the slave clock and the master clock and a network delay between the second device and the first device based on the first time stamp, the second time stamp, the third time stamp and the fourth time stamp;
and inputting the time deviation and the network time delay into a preset deviation rectifying formula to obtain deviation rectifying time, and adjusting the slave clock by using the deviation rectifying time.
Optionally, the clock synchronization system further includes a first acquisition device and a second acquisition device; the first acquisition device is respectively in communication connection with the network layer of the first equipment and the first wireless communication module; the second acquisition device is respectively in communication connection with the network layer of the second equipment and the second wireless communication module;
the first timestamp is obtained by adopting the following steps:
the first device sends a synchronous message to the second device, so that when the first acquisition device detects that a message sent from a network layer of the first device is the synchronous message, an interrupt used for recording the current time of the first acquisition device is generated, the recorded current time is used as the first timestamp and sent to the first device, and the first device sends a following message carrying the first timestamp to the second device;
the second equipment acquires the first timestamp from the following message when receiving the following message;
the second timestamp is obtained by adopting the following steps:
when the second acquisition device detects that the message sent from the second wireless communication module is the synchronization message, generating an interrupt for recording the current time of the second acquisition device, and sending the recorded current time to the second device as the second timestamp, so that the second device records the second timestamp.
Optionally, the third timestamp is obtained by the following steps:
when receiving the following message, the second device sends a delay request message to the first device by using the second acquisition device, so that when detecting that a message sent from a network layer of the second device is the delay request message, the second acquisition device generates an interrupt for recording the current time of the second acquisition device, and sends the recorded current time as the third timestamp to the second device, so that the second device records the third timestamp.
Optionally, when receiving the following message, the second device sends a delay request message to the first device;
the fourth timestamp is obtained by adopting the following steps:
when the first acquisition device detects that the message sent from the second wireless communication module is the delay request message, generating an interrupt for recording the current time of the first acquisition device, and sending the recorded current time to the first equipment as the fourth timestamp, so that the first equipment sends a delay response message carrying the fourth timestamp to the second equipment;
and when receiving the delay response message, the second device acquires the fourth timestamp from the delay response message.
In a second aspect, an embodiment of the present invention provides a clock synchronization system for a wireless network based on an IEEE1588 protocol, where the clock synchronization system includes: the wireless communication method comprises the following steps that first equipment and second equipment are used, wherein a clock of the first equipment is a master clock, a clock of the second equipment is a slave clock, and wireless communication between the first equipment and the second equipment is realized through a first wireless communication module corresponding to the first equipment and a second wireless communication module corresponding to the second equipment;
the first device is configured to send a synchronization message to the second device, and receive a delay request message sent by the second device;
the second device is used for respectively acquiring a first time stamp, a second time stamp, a third time stamp and a fourth time stamp; acquiring a time offset between the slave clock and the master clock and a network delay between the second device and the first device based on the first time stamp, the second time stamp, the third time stamp and the fourth time stamp; inputting the time deviation and the network time delay into a preset deviation rectifying formula to obtain deviation rectifying time, and adjusting the slave clock by using the deviation rectifying time;
the first timestamp is a time when the synchronization packet leaves a network layer of the first device and reaches the first wireless communication module; the second timestamp is a time before the synchronization packet leaves the second wireless communication module and reaches a network layer of the second device; the third timestamp is a time when the delay request message leaves a network layer of the second device and reaches the second wireless communication module; the fourth timestamp is a time before the delay request packet leaves the first wireless communication module and reaches the network layer of the first device.
Optionally, the clock synchronization system further includes a first acquisition device and a second acquisition device; the first acquisition device is respectively in communication connection with the network layer of the first equipment and the first wireless communication module; the second acquisition device is respectively in communication connection with the network layer of the second equipment and the second wireless communication module;
the obtaining of the first timestamp comprises:
when the first acquisition device detects that a message sent from a network layer of the first equipment is the synchronous message, generating an interrupt for recording the current time of the first acquisition device, and sending the recorded current time to the first equipment as the first timestamp, so that the first equipment sends a following message carrying the first timestamp to the second equipment; the second equipment acquires the first timestamp from the following message when receiving the following message;
the obtaining of the second timestamp comprises:
when the second acquisition device detects that the message sent from the second wireless communication module is the synchronization message, generating an interrupt for recording the current time of the second acquisition device, and sending the recorded current time to the second device as the second timestamp, so that the second device records the second timestamp.
Optionally, the obtaining of the third timestamp includes:
when receiving the following message, the second device sends a delay request message to the first device by using the second acquisition device, so that when detecting that a message sent from a network layer of the second device is the delay request message, the second acquisition device generates an interrupt for recording the current time of the second acquisition device, and sends the recorded current time as the third timestamp to the second device, so that the second device records the third timestamp.
Optionally, when receiving the following message, the second device sends a delay request message to the first device;
the obtaining of the fourth timestamp comprises:
when the first acquisition device detects that the message sent from the second wireless communication module is the delay request message, generating an interrupt for recording the current time of the first acquisition device, and sending the recorded current time to the first equipment as the fourth timestamp, so that the first equipment sends a delay response message carrying the fourth timestamp to the second equipment;
and when receiving the delay response message, the second device acquires the fourth timestamp from the delay response message.
In a third aspect, an embodiment of the present invention provides an electronic device, where the electronic device includes a processor, a communication interface, a memory, and a communication bus, where the processor and the communication interface complete communication between the processor and the communication interface through the communication bus, and the memory is used for storing a computer program; and the processor is used for realizing the clock synchronization method of the wireless network based on the IEEE1588 protocol provided by the first aspect when executing the program stored in the memory.
In a third aspect, an embodiment of the present invention provides a computer-readable storage medium, where a computer program is stored in the computer-readable storage medium, and when the computer program is executed by a processor, the method for clock synchronization of a wireless network based on an IEEE1588 protocol provided in the first aspect is implemented.
In the scheme provided by the embodiment of the invention, the second device of the clock synchronization system respectively acquires a first time stamp, a second time stamp, a third time stamp and a fourth time stamp, and further acquires the time deviation between the slave clock and the master clock and the network delay between the second device and the first device based on the first time stamp, the second time stamp, the third time stamp and the fourth time stamp; therefore, the time deviation and the network time delay are input into a preset deviation rectifying formula to obtain deviation rectifying time, and the deviation rectifying time is used for adjusting a slave clock to realize clock synchronization between first equipment and second equipment which are communicated in a wireless network. The wireless communication between the first device and the second device is realized through a first wireless communication module corresponding to the first device and a second wireless communication module corresponding to the second device. The first timestamp is the time when the synchronization message leaves the network layer of the first device and reaches the first wireless communication module; the second timestamp is the time before the synchronous message leaves the second wireless communication module and reaches the network layer of the second device; the third timestamp is the time when the delay request message leaves the network layer of the second device and reaches the second wireless communication module; the fourth timestamp is a time before the delay request packet leaves the first wireless communication module and reaches the network layer of the first device. Therefore, compared with the method that the time when a message is between the network layer and the communication link layer of the device is taken as the timestamp, the time difference caused by neglecting the transmission delay of the transmission layer and the network layer can be reduced by taking the current time when the message reaches the application layer of the device as the timestamp of any message as the timestamp of the message, and each timestamp is closer to the time when the message reaches or leaves the physical address of the device in the transmission process and is closer to the real sending or receiving time of the message, thereby improving the precision of the clock synchronization realized by using the timestamp.
Of course, not all of the advantages described above need to be achieved at the same time in the practice of any one product or method of the invention.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a clock synchronization system of a wireless network based on an IEEE1588 protocol according to an embodiment of the present invention;
fig. 2 is a schematic flowchart of a clock synchronization method for a wireless network based on IEEE1588 protocol according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a clock synchronization system of a wireless network based on IEEE1588 protocol according to another embodiment of the present invention;
fig. 4 is a flowchart illustrating a clock synchronization method for a wireless network based on IEEE1588 protocol according to another embodiment of the present invention;
fig. 5 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
For convenience of understanding, the following first describes a clock synchronization system of a wireless network based on IEEE1588 protocol according to an embodiment of the present invention.
As shown in fig. 1, a clock synchronization system of a wireless network based on IEEE1588 protocol according to an embodiment of the present invention includes: the wireless communication method comprises the following steps that a first device 101 and a second device 102 are arranged, wherein a clock of the first device 101 is a master clock, a clock of the second device 102 is a slave clock, and wireless communication between the first device 101 and the second device 102 is achieved through a first wireless communication module 103 corresponding to the first device 101 and a second wireless communication module 104 corresponding to the second device 102;
the first device 101 is configured to send a synchronization message to the second device, and receive a delay request message sent by the second device 102;
the second device 102 is configured to obtain a first timestamp, a second timestamp, a third timestamp, and a fourth timestamp, respectively; acquiring a time deviation between a slave clock and a master clock and a network delay between the second device 102 and the first device 101 based on the first time stamp, the second time stamp, the third time stamp and the fourth time stamp; inputting the time deviation and the network delay into a preset deviation-correcting formula to obtain deviation-correcting time, and adjusting a slave clock by using the deviation-correcting time;
the first timestamp is a time when the sync packet leaves the network layer of the first device 101 and reaches the first wireless communication module 103; the second timestamp is a time before the synchronization packet leaves the second wireless communication module 104 and reaches the network layer of the second device 102; the third timestamp is a time when the delay request packet leaves the network layer of the second device 102 and reaches the second wireless communication module 104; the fourth timestamp is a time before the delay request packet leaves the first wireless communication module 103 and reaches the network layer of the first device 101.
In a particular application, the first device 101 and the second device 102 may be various. For example, the first device 101 or the second device 102 may specifically include a computer, a mobile terminal, a wearable device, a server, and other electronic devices. Also, the first wireless communication module 103 may be included in the first device 101, or may be independent of the first device 101; the second wireless communication module 104 may be included in the second device 102 or may be separate from the second device 102. For example, in order to meet the processing speed and interface requirements of clock synchronization, the processors of the first device and the second device may be specifically eight-core processors, and 64-bit data and a larger virtual address addressing space can be supported; the CPU master frequency is 1.4GHz at most; the memory bandwidth of 6.4GB/s is provided, and the interface resources such as SDIO bus and the like are abundant. The first wireless communication module and the second wireless communication module may be specifically WLAN modules. Specifically, the model of the WLAN module may be selected according to the requirement for wireless communication performance.
Moreover, the more accurate the timestamp acquired at a position closer to the bottom layer, the time when the message leaves the network layer of the device and reaches the wireless communication module for the first device and the second device which utilize the wireless network communication is relatively closest to the real time of sending or receiving the message. Therefore, the first timestamp is a time when the sync packet leaves the network layer of the first device 101 and reaches the first wireless communication module 103; the second timestamp is a time before the synchronization packet leaves the second wireless communication module 104 and reaches the network layer of the second device 102; the third timestamp is a time when the delay request packet leaves the network layer of the second device 102 and reaches the second wireless communication module 104; the fourth timestamp is a time before the delay request packet leaves the first wireless communication module 103 and reaches the network layer of the first device 101.
For ease of understanding and reasonable layout, the way of obtaining each timestamp is described in detail in the embodiment of fig. 2 of the present invention.
In the scheme provided by the embodiment of the invention, the second device of the clock synchronization system respectively acquires a first time stamp, a second time stamp, a third time stamp and a fourth time stamp, and further acquires the time deviation between the slave clock and the master clock and the network delay between the second device and the first device based on the first time stamp, the second time stamp, the third time stamp and the fourth time stamp; therefore, the time deviation and the network time delay are input into a preset deviation rectifying formula to obtain deviation rectifying time, and the deviation rectifying time is used for adjusting a slave clock to realize clock synchronization between first equipment and second equipment which are communicated in a wireless network. The wireless communication between the first device and the second device is realized through a first wireless communication module corresponding to the first device and a second wireless communication module corresponding to the second device. The first timestamp is the time when the synchronization message leaves the network layer of the first device and reaches the first wireless communication module; the second timestamp is the time before the synchronous message leaves the second wireless communication module and reaches the network layer of the second device; the third timestamp is the time when the delay request message leaves the network layer of the second device and reaches the second wireless communication module; the fourth timestamp is a time before the delay request packet leaves the first wireless communication module and reaches the network layer of the first device. Therefore, compared with the method that the time when a message is between the network layer and the communication link layer of the device is taken as the timestamp, the time difference caused by neglecting the transmission delay of the transmission layer and the network layer can be reduced by taking the current time when the message reaches the application layer of the device as the timestamp of any message as the timestamp of the message, and each timestamp is closer to the time when the message reaches or leaves the physical address of the device in the transmission process and is closer to the real sending or receiving time of the message, thereby improving the precision of the clock synchronization realized by using the timestamp.
As shown in fig. 2, the clock synchronization method of the wireless network based on the IEEE1588 protocol according to an embodiment of the present invention is applied to the second device in the clock synchronization system of the wireless network based on the IEEE1588 protocol provided in the embodiment of fig. 1 of the present invention, and the method may include the following steps:
s201, respectively obtaining a first time stamp, a second time stamp, a third time stamp and a fourth time stamp. The first timestamp is the time when the synchronous message leaves a network layer of the first device and reaches the first wireless communication module; the second timestamp is the time before the synchronous message leaves the second wireless communication module and reaches the network layer of the second device; the third timestamp is the time when the delay request message leaves the network layer of the second device and reaches the second wireless communication module; the fourth timestamp is a time before the delay request packet leaves the first wireless communication module and reaches the network layer of the first device.
The second device may obtain the first time stamp, the second time stamp, the third time stamp, and the fourth time stamp in multiple manners. For example, the second device may obtain the first timestamp from a following message carrying the first timestamp sent by the first device; or, when the synchronization packet carries the first timestamp, the second device may obtain the first timestamp from the synchronization packet. Illustratively, the second device may directly record the second timestamp; or, when the synchronization packet carries the second timestamp, the second device may obtain the second timestamp from the synchronization packet. Illustratively, the second device may directly record the second timestamp; or, when the synchronization packet carries the second timestamp, the second device may obtain the second timestamp from the synchronization packet. For example, the second device may obtain the fourth timestamp from a delay response message carrying the fourth timestamp and sent by the first device; or, when the first acquisition apparatus is connected between the network layer of the first device and the first wireless module, the second device may receive the fourth timestamp sent by the first acquisition apparatus. For convenience of understanding and reasonable layout, in the embodiment of fig. 4 of the present invention, a specific description is subsequently made on the manner of acquiring the timestamps.
Any obtaining manner that can obtain the first time stamp, the second time stamp, the third time stamp and the fourth time stamp can be used in the present invention, and the present embodiment does not limit this.
And S202, acquiring the time deviation between the slave clock and the master clock and the network time delay between the second device and the first device based on the first time stamp, the second time stamp, the third time stamp and the fourth time stamp.
In a specific application, the second device may input the first time stamp, the second time stamp, the third time stamp, and the fourth time stamp into a preset time deviation formula to obtain a time deviation between the slave clock and the master clock. And the second device may input the first time stamp, the second time stamp, the third time stamp, and the fourth time stamp into a preset network delay formula to obtain the network delay between the second device and the first device.
The preset time deviation formula may be the following formula one:
offset is the time offset between the slave clock and the master clock, and t1 is the first timestamp; t2 is a second timestamp; t3 is a third timestamp; t4 is a fourth timestamp.
The preset network delay formula may be the following formula two:
And S203, inputting the time deviation and the network delay into a preset deviation rectifying formula to obtain deviation rectifying time, and adjusting the slave clock by using the deviation rectifying time.
The preset deviation rectifying formula specifically may be: and (5) correcting the deviation time, namely +/-from the current time of the clock (time deviation + network delay). In addition, the operation sign "±" in the formula may be selected to be "+" or "-" according to the IEEE1588 protocol for operation according to specific communication parameters.
In the scheme provided by the embodiment of the invention, the second device of the clock synchronization system respectively acquires a first time stamp, a second time stamp, a third time stamp and a fourth time stamp, and further acquires the time deviation between the slave clock and the master clock and the network delay between the second device and the first device based on the first time stamp, the second time stamp, the third time stamp and the fourth time stamp; therefore, the time deviation and the network time delay are input into a preset deviation rectifying formula to obtain deviation rectifying time, and the deviation rectifying time is used for adjusting a slave clock to realize clock synchronization between first equipment and second equipment which are communicated in a wireless network. The wireless communication between the first device and the second device is realized through a first wireless communication module corresponding to the first device and a second wireless communication module corresponding to the second device. The first timestamp is the time when the synchronization message leaves the network layer of the first device and reaches the first wireless communication module; the second timestamp is the time before the synchronous message leaves the second wireless communication module and reaches the network layer of the second device; the third timestamp is the time when the delay request message leaves the network layer of the second device and reaches the second wireless communication module; the fourth timestamp is a time before the delay request packet leaves the first wireless communication module and reaches the network layer of the first device. Therefore, compared with the method that the time when a message is between the network layer and the communication link layer of the device is taken as the timestamp, the time difference caused by neglecting the transmission delay of the transmission layer and the network layer can be reduced by taking the current time when the message reaches the application layer of the device as the timestamp of any message as the timestamp of the message, and each timestamp is closer to the time when the message reaches or leaves the physical address of the device in the transmission process and is closer to the real sending or receiving time of the message, thereby improving the precision of the clock synchronization realized by using the timestamp.
As shown in fig. 3, a clock synchronization system of a wireless network based on IEEE1588 protocol according to another embodiment of the present invention includes: a first device 301, a second device 302, a first acquisition apparatus 305 and a second acquisition apparatus 306. The clock of the first device 301 is a master clock, the clock of the second device 302 is a slave clock, and the wireless communication between the first device 301 and the second device 302 is realized through a first wireless communication module 303 corresponding to the first device 301 and a second wireless communication module 304 corresponding to the second device 302; the first acquisition device 305 is respectively in communication connection with the network layer of the first device 301 and the first wireless communication module 303; the second acquisition device 306 is respectively in communication connection with the network layer of the second device 302 and the second wireless communication module 304;
the first device 301 is configured to send a synchronization message to the second device, and receive a delay request message sent by the second device 102;
a second device 302, configured to obtain a first timestamp, a second timestamp, a third timestamp, and a fourth timestamp, respectively; acquiring a time deviation between a slave clock and a master clock and a network delay between the second device 102 and the first device 101 based on the first time stamp, the second time stamp, the third time stamp and the fourth time stamp; inputting the time deviation and the network delay into a preset deviation-correcting formula to obtain deviation-correcting time, and adjusting a slave clock by using the deviation-correcting time;
a first acquisition device 305, configured to generate an interrupt for recording a current time of the first acquisition device 305 when detecting that a packet sent from a network layer of the first device 301 is a synchronization packet, and send the recorded current time to the first device 301 as a first timestamp, so that the first device 301 sends a following packet carrying the first timestamp to the second device 302; when receiving the following message, the second device 302 acquires a first timestamp from the following message;
the second acquisition device 306 is configured to generate an interrupt for recording the current time of the second acquisition device 306 when detecting that the message sent from the second wireless communication module 304 is a synchronization message, and send the recorded current time to the second device 302 as a second timestamp, so that the second device 302 records the second timestamp.
In a specific application, the first collecting device may be a part of the first apparatus, or may be independent of the first apparatus; the second acquisition means may be part of the second apparatus or may be separate from the second apparatus. The first and second acquisition devices may be FPGAs (Field Programmable Gate arrays), and specific models may be selected according to performance requirements of wireless communication, where the FPGAs have high-precision clocks. For example, when a 50M active crystal oscillator detects a relevant message, the current time of the FPGA high-precision clock may be recorded by a corresponding logic circuit as a timestamp. In order to transmit and collect the timestamps, the first wireless communication module and the SDIO interface of the first device need to be connected to the common I/O port of the first collecting device; and connecting the second wireless communication module and the SDIO interface of the second equipment to the common I/O port of the second acquisition device. In order to improve the message transmission efficiency, the first equipment and the first acquisition device use a CPU bus for communication; and the second equipment and the second acquisition device communicate by using a CPU bus.
For ease of understanding and reasonable layout, in the embodiment of fig. 4 of the present invention, the way in which the system acquires the timestamps and performs clock synchronization will be described in detail later.
As shown in fig. 4, a clock synchronization method of a wireless network based on IEEE1588 protocol according to another embodiment of the present invention is applied to the clock synchronization system of the wireless network based on IEEE1588 protocol provided in the embodiment of fig. 3 of the present invention, and the method may include the following steps:
s401, the first device sends a synchronous message to the second device.
Because a first acquisition device is connected between the first device and the first wireless communication module, the transmission path of the synchronization message sent by the first device is as follows in sequence: the device comprises an application layer of first equipment, a transmission layer of the first equipment, a network layer of the first equipment, a first acquisition device, a first wireless communication module, a second acquisition device, a network layer of the second equipment, a transmission layer of the second equipment and an application layer of the second equipment.
Moreover, the first device and the second device store IEEE1588 protocol and TCP/IP protocol clusters, so that the first device and the second device can implement basic wireless communication, and further perform sending and receiving of a synchronization message. Specifically, the first device may send the synchronization packet according to an IEEE1588 protocol, and at this time, the application layer of the first device transmits data used for generating the synchronization packet to the lower layer as user data, and the data sequentially passes through the transport layer and the network layer of the first device. For example, when the sync message reaches the transport layer, the first device performs packet encapsulation on data used for generating the sync message according to a UDP (User Datagram Protocol) message format specified by a network Protocol stack: adding UDP header and filling the PTP (Precision Time Protocol) message data transmitted from the upper layer into UDP user data field; further sending the packaged message to a network layer of the first device; and IP encapsulation is carried out on the upper layer message in the network layer, and information such as an IP header is mainly added.
Similarly, the receiving and sending of the subsequent delay request message, the following message and the delay response message can be realized, compared with the receiving and sending of the synchronous message, the difference is that the messages are different, and the synchronous message can be referred to by comparing the same parts.
S402, when the second acquisition device detects that the message sent from the second wireless communication module is a synchronous message, generating an interrupt for recording the current moment of the second acquisition device.
When the synchronous message reaches the second wireless communication module, the head and the tail of an Ethernet frame are added to the message at a data link layer of the second wireless communication module, and the synchronous message in the form of the Ethernet frame is obtained. On the basis, the network interface chip of the second wireless communication module converts the message into a level signal suitable for transmission of a physical medium, so that the message is transmitted on the physical medium of a wireless network environment through the antenna. And when the second wireless communication module receives the synchronous message, the synchronous message can be decapsulated successively through a physical layer and a link data layer of the second wireless communication module, and the decapsulated message is sent out. Similarly, the first wireless communication module may perform the same processing on the synchronization message.
And S403, the second acquisition device sends the recorded current time as a second timestamp to the second equipment.
S404, the second device records the second time stamp.
S405, when detecting that a packet sent from the network layer of the first device is a synchronization packet, the first acquisition device generates an interrupt for recording a current time of the first acquisition device.
And S406, the first acquisition device sends the recorded current time as a first timestamp to the first equipment.
S407, the first device sends the following message carrying the first timestamp to the second device.
S408, when the second device receives the following message, the first timestamp is obtained from the following message.
And S409, when the second equipment receives the following message, the second acquisition device is used for sending a delay request message to the first equipment.
And S410, when detecting that the message sent from the network layer of the second device is a delay request message, the second acquisition device generates an interrupt for recording the current moment of the second acquisition device.
And S411, the second acquisition device sends the recorded current time as a third timestamp to the second equipment.
And S412, the second device records the third time stamp.
The above steps S409 to S412 are optional steps for acquiring the third time stamp.
S413, when detecting that the message sent from the second wireless communication module is the delay request message, the first collection device generates an interrupt for recording the current time of the first collection device.
And S414, the first acquisition device sends the recorded current time as a fourth timestamp to the first equipment.
S415, the first device sends a delay response packet carrying the fourth timestamp to the second device.
S416, when receiving the delay response packet, the second device obtains a fourth timestamp from the delay response packet.
The above-mentioned steps S413 to S412 are optional steps for acquiring the fourth time stamp, and step S413 may be executed after step S409.
S417, acquiring a time deviation between the slave clock and the master clock and a network delay between the second device and the first device based on the first time stamp, the second time stamp, the third time stamp and the fourth time stamp.
And S418, inputting the time deviation and the network delay into a preset deviation rectifying formula to obtain deviation rectifying time, and adjusting the slave clock by utilizing the deviation rectifying time.
S417 to S418 are the same as S202 to S203 in the embodiment of fig. 2, and are not repeated herein, for details, see the description of the embodiment of fig. 2.
In the embodiment of fig. 4 of the present invention, the first timestamp and the fourth timestamp are obtained in a two-step mode: and the first equipment independently sends the following message carrying the first time stamp and the delayed response message carrying the fourth time stamp to the second equipment. And a single step mode: carry first timestamp in the synchronous message to and directly return the fourth timestamp by the second collection system and compare for the second equipment, can guarantee that first collection system need not to add the timestamp to the synchronous message in, can reduce the time delay that adds the timestamp and cause, improve the synchronism of message receiving and dispatching in-process time delay among the wireless communication, further improve the synchronous precision of clock. Similarly, the second acquisition device does not need to send the timestamp again after recording the timestamp, and time delay can be reduced.
An embodiment of the present invention further provides an electronic device, as shown in fig. 5, which includes a processor 501, a communication interface 502, a memory 503 and a communication bus 504, where the processor 501, the communication interface 502 and the memory 503 complete mutual communication through the communication bus 504,
a memory 503 for storing a computer program;
the processor 501, when executing the program stored in the memory 503, implements the following steps:
respectively acquiring a first time stamp, a second time stamp, a third time stamp and a fourth time stamp; the first timestamp is the time when the synchronization message leaves the network layer of the first device and reaches the first wireless communication module; the second timestamp is a time before the synchronization packet leaves the second wireless communication module and reaches a network layer of the second device; the third timestamp is a time when the delay request message leaves the network layer of the second device and reaches the second wireless communication module; the fourth timestamp is a time before the delay request packet leaves the first wireless communication module and reaches a network layer of the first device;
acquiring a time offset between the slave clock and the master clock and a network delay between the second device and the first device based on the first time stamp, the second time stamp, the third time stamp and the fourth time stamp;
and inputting the time deviation and the network time delay into a preset deviation rectifying formula to obtain deviation rectifying time, and adjusting the slave clock by using the deviation rectifying time.
In a specific application, the electronic device may be a second device in a clock synchronization system of a wireless network based on IEEE1588 protocol.
The communication bus mentioned in the electronic device may be a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, or the like. The communication bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one thick line is shown, but this does not mean that there is only one bus or one type of bus.
The communication interface is used for communication between the electronic equipment and other equipment.
The Memory may include a Random Access Memory (RAM) or a Non-Volatile Memory (NVM), such as at least one disk Memory. Optionally, the memory may also be at least one memory device located remotely from the processor.
The Processor may be a general-purpose Processor, including a Central Processing Unit (CPU), a Network Processor (NP), and the like; but also Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) or other Programmable logic devices, discrete Gate or transistor logic devices, discrete hardware components.
In another embodiment provided by the present invention, a computer-readable storage medium is further provided, in which a computer program is stored, and the computer program, when executed by a processor, implements the steps of any one of the above-mentioned clock synchronization methods for a wireless network based on IEEE1588 protocol.
In a further embodiment of the present invention, there is also provided a computer program product containing instructions which, when run on a computer, cause the computer to perform any of the above-described embodiments of the method for clock synchronization for a wireless network based on the IEEE1588 protocol.
In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, cause the processes or functions described in accordance with the embodiments of the invention to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, from one website site, computer, server, or data center to another website site, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that incorporates one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
All the embodiments in the present specification are described in a related manner, and the same and similar parts among the embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.
The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.
Claims (10)
1. A clock synchronization method of a wireless network based on an IEEE1588 protocol is characterized in that the clock synchronization method is applied to a second device of a clock synchronization system, and the clock synchronization system further comprises a first device, a first acquisition device and a second acquisition device; the clock of the first device is a master clock, the clock of the second device is a slave clock, the wireless communication between the first device and the second device is realized through a first wireless communication module corresponding to the first device and a second wireless communication module corresponding to the second device, the first acquisition device is in communication connection with a network layer of the first device through a CPU (central processing unit) bus, and the first acquisition device is also in communication connection with the first wireless communication module; the second acquisition device is in communication connection with a network layer of the second equipment by using a CPU bus, and the second acquisition device is also in communication connection with the second wireless communication module, and the method comprises the following steps:
acquiring a first timestamp and a fourth timestamp through the first acquisition device, and acquiring a second timestamp and a third timestamp through the second acquisition device; the first timestamp is the time when the synchronization message leaves the network layer of the first device and reaches the first wireless communication module; the second timestamp is a time before the synchronization packet leaves the second wireless communication module and reaches a network layer of the second device; the third timestamp is a time when the delay request message leaves the network layer of the second device and reaches the second wireless communication module; the fourth timestamp is a time before the delay request message leaves the first wireless communication module and reaches a network layer of the first device, and the first acquisition device and the second acquisition device are field programmable logic gate arrays;
acquiring a time offset between the slave clock and the master clock and a network delay between the second device and the first device based on the first time stamp, the second time stamp, the third time stamp and the fourth time stamp;
and inputting the time deviation and the network time delay into a preset deviation rectifying formula to obtain deviation rectifying time, and adjusting the slave clock by using the deviation rectifying time.
2. The method of claim 1, wherein the first timestamp is obtained by:
the first device sends a synchronous message to the second device, so that when the first acquisition device detects that a message sent from a network layer of the first device is the synchronous message, an interrupt used for recording the current time of the first acquisition device is generated, the recorded current time is used as the first timestamp and sent to the first device, and the first device sends a following message carrying the first timestamp to the second device;
the second equipment acquires the first timestamp from the following message when receiving the following message;
the second timestamp is obtained by adopting the following steps:
when the second acquisition device detects that the message sent from the second wireless communication module is the synchronization message, generating an interrupt for recording the current time of the second acquisition device, and sending the recorded current time to the second device as the second timestamp, so that the second device records the second timestamp.
3. The method of claim 2, wherein the third timestamp is obtained by:
when receiving the following message, the second device sends a delay request message to the first device by using the second acquisition device, so that when detecting that a message sent from a network layer of the second device is the delay request message, the second acquisition device generates an interrupt for recording the current time of the second acquisition device, and sends the recorded current time as the third timestamp to the second device, so that the second device records the third timestamp.
4. The method according to claim 3, wherein the second device sends a delay request message to the first device when receiving the follow message;
the fourth timestamp is obtained by adopting the following steps:
when the first acquisition device detects that the message sent from the second wireless communication module is the delay request message, generating an interrupt for recording the current time of the first acquisition device, and sending the recorded current time to the first equipment as the fourth timestamp, so that the first equipment sends a delay response message carrying the fourth timestamp to the second equipment;
and when receiving the delay response message, the second device acquires the fourth timestamp from the delay response message.
5. A clock synchronization system of a wireless network based on an IEEE1588 protocol, characterized in that the clock synchronization system comprises: the wireless communication method comprises the following steps that first equipment, second equipment, a first acquisition device and a second acquisition device are adopted, wherein a clock of the first equipment is a master clock, a clock of the second equipment is a slave clock, wireless communication between the first equipment and the second equipment is realized through a first wireless communication module corresponding to the first equipment and a second wireless communication module corresponding to the second equipment, the first acquisition device is in communication connection with a network layer of the first equipment through a CPU (central processing unit) bus, and the first acquisition device is also in communication connection with the first wireless communication module; the second acquisition device is in communication connection with a network layer of the second equipment by using a CPU bus, and is also in communication connection with the second wireless communication module;
the first device is configured to send a synchronization message to the second device, and receive a delay request message sent by the second device;
the second device is used for acquiring a first timestamp and a fourth timestamp through the first acquisition device, and acquiring a second timestamp and a third timestamp through the second acquisition device; acquiring a time offset between the slave clock and the master clock and a network delay between the second device and the first device based on the first time stamp, the second time stamp, the third time stamp and the fourth time stamp; inputting the time deviation and the network time delay into a preset deviation rectifying formula to obtain deviation rectifying time, and adjusting the slave clock by using the deviation rectifying time;
the first timestamp is a time when the synchronization packet leaves a network layer of the first device and reaches the first wireless communication module; the second timestamp is a time before the synchronization packet leaves the second wireless communication module and reaches a network layer of the second device; the third timestamp is a time when the delay request message leaves a network layer of the second device and reaches the second wireless communication module; the fourth timestamp is a time before the delay request packet leaves the first wireless communication module and reaches a network layer of the first device, and the first collecting device and the second collecting device are field programmable gate arrays.
6. The system of claim 5, wherein the obtaining of the first timestamp comprises:
when the first acquisition device detects that a message sent from a network layer of the first equipment is the synchronous message, generating an interrupt for recording the current time of the first acquisition device, and sending the recorded current time to the first equipment as the first timestamp, so that the first equipment sends a following message carrying the first timestamp to the second equipment; the second equipment acquires the first timestamp from the following message when receiving the following message;
the obtaining of the second timestamp comprises:
when the second acquisition device detects that the message sent from the second wireless communication module is the synchronization message, generating an interrupt for recording the current time of the second acquisition device, and sending the recorded current time to the second device as the second timestamp, so that the second device records the second timestamp.
7. The system of claim 6, wherein the obtaining of the third timestamp comprises:
when receiving the following message, the second device sends a delay request message to the first device by using the second acquisition device, so that when detecting that a message sent from a network layer of the second device is the delay request message, the second acquisition device generates an interrupt for recording the current time of the second acquisition device, and sends the recorded current time as the third timestamp to the second device, so that the second device records the third timestamp.
8. The system according to claim 7, wherein the second device sends a delay request message to the first device when receiving the follow message;
the obtaining of the fourth timestamp comprises:
when the first acquisition device detects that the message sent from the second wireless communication module is the delay request message, generating an interrupt for recording the current time of the first acquisition device, and sending the recorded current time to the first equipment as the fourth timestamp, so that the first equipment sends a delay response message carrying the fourth timestamp to the second equipment;
and when receiving the delay response message, the second device acquires the fourth timestamp from the delay response message.
9. An electronic device, comprising a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface, the memory completes communication with each other through the communication bus, and the memory is used for storing computer programs; a processor for implementing the steps of the method according to any one of claims 1 to 4 when executing a program stored in the memory.
10. A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 4.
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| CN112312537B (en) * | 2020-10-14 | 2022-04-08 | 珠海格力电器股份有限公司 | Clock synchronization method and device, storage medium and electronic device |
| CN114389733B (en) * | 2020-10-21 | 2023-07-21 | 大唐移动通信设备有限公司 | PTP master clock device, clock synchronization method, and storage medium |
| CN113014351B (en) * | 2021-03-15 | 2022-07-22 | 四川英得赛克科技有限公司 | Non-invasive time synchronization method, system and storage medium |
| CN113453053B (en) * | 2021-06-25 | 2022-05-06 | 杭州海康威视数字技术股份有限公司 | Distributed video synchronous display system, video synchronous display method and storage medium |
| CN116528346A (en) * | 2022-01-24 | 2023-08-01 | 华为技术有限公司 | Time synchronization method, device and system |
| CN114285542B (en) * | 2022-01-28 | 2023-10-13 | 高新兴物联科技股份有限公司 | Network time correction method, device and computer readable storage medium |
| CN114793143B (en) * | 2022-06-27 | 2022-08-30 | 北京智芯微电子科技有限公司 | Network timing method and device, electronic equipment and readable storage medium |
| CN115642976B (en) * | 2022-10-10 | 2023-07-21 | 广东越新微系统研究院 | Mixed optimization time synchronization method |
| CN116436555B (en) * | 2023-06-09 | 2023-08-18 | 新华三技术有限公司 | Time synchronization method and device and distributed network equipment |
| CN117728913A (en) * | 2023-12-27 | 2024-03-19 | 小米汽车科技有限公司 | Method, device, storage medium and vehicle for time synchronization |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101335587A (en) * | 2008-07-23 | 2008-12-31 | 重庆邮电大学 | Accurate time synchronization method for industrial wireless network |
| CN102547969A (en) * | 2012-02-24 | 2012-07-04 | 电子科技大学 | High-accuracy wireless clock synchronization system for power system |
| CN104836630A (en) * | 2015-05-21 | 2015-08-12 | 大连理工大学 | IEEE1588 clock synchronization system and implementation method therefor |
| CN108880727A (en) * | 2018-06-13 | 2018-11-23 | 合肥工业大学 | A kind of precision clock synchronization realizing method based on PTPd2 agreement |
| CN109327900A (en) * | 2018-11-23 | 2019-02-12 | 中国电子科技集团公司第五十四研究所 | A kind of positioning time service method based on non-spread spectrum radio communication system |
| CN110572230A (en) * | 2019-09-10 | 2019-12-13 | 北京邮电大学 | correction method and device for realizing time synchronization |
| CN111083775A (en) * | 2019-11-06 | 2020-04-28 | 重庆邮电大学 | IPv6 wireless sensor network time synchronization method based on RPL routing protocol |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102111380B (en) * | 2009-12-25 | 2014-05-07 | 华为技术有限公司 | Time synchronization method, device and system |
| CN108650051B (en) * | 2018-05-10 | 2019-06-21 | 西安电子科技大学 | The clock synchronization apparatus and method of general devices at full hardware single step 1588 |
| CN110176973B (en) * | 2019-05-17 | 2020-12-04 | 固高科技(深圳)有限公司 | Method, system, computer device and storage medium for clock synchronization |
-
2020
- 2020-04-30 CN CN202010362722.7A patent/CN111555834B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101335587A (en) * | 2008-07-23 | 2008-12-31 | 重庆邮电大学 | Accurate time synchronization method for industrial wireless network |
| CN102547969A (en) * | 2012-02-24 | 2012-07-04 | 电子科技大学 | High-accuracy wireless clock synchronization system for power system |
| CN104836630A (en) * | 2015-05-21 | 2015-08-12 | 大连理工大学 | IEEE1588 clock synchronization system and implementation method therefor |
| CN108880727A (en) * | 2018-06-13 | 2018-11-23 | 合肥工业大学 | A kind of precision clock synchronization realizing method based on PTPd2 agreement |
| CN109327900A (en) * | 2018-11-23 | 2019-02-12 | 中国电子科技集团公司第五十四研究所 | A kind of positioning time service method based on non-spread spectrum radio communication system |
| CN110572230A (en) * | 2019-09-10 | 2019-12-13 | 北京邮电大学 | correction method and device for realizing time synchronization |
| CN111083775A (en) * | 2019-11-06 | 2020-04-28 | 重庆邮电大学 | IPv6 wireless sensor network time synchronization method based on RPL routing protocol |
Non-Patent Citations (1)
| Title |
|---|
| 基于IEEE 1588协议的精确时钟同步系统的研究与设计实现;陶稳静;《中国优秀硕士学位论文全文数据库 信息科技辑》;20191115;第二、四章 * |
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