CN118074839A - Clock synchronization method, device and system - Google Patents

Abstract

The embodiment of the application provides a clock synchronization method, a clock synchronization device and a clock synchronization system, which comprise the following steps: the method comprises the steps that a first node sends a subscription request message to a control node, wherein the subscription request message is used for subscribing clock synchronization services of the first node and a second node, and the second node is a node which performs clock synchronization with the first node; the control node determines a strategy sending message according to the subscription request message, wherein the strategy sending message comprises a clock synchronization algorithm; the first node obtains a clock synchronization parameter for a clock synchronization service, the clock synchronization parameter being determined according to a clock synchronization algorithm. The clock synchronization method, the clock synchronization device and the clock synchronization system provided by the embodiment of the application can be applied to heterogeneous systems with complex structures, and the system resource expenditure is reduced on the premise of meeting the node synchronization requirement.

Description

Clock synchronization method, device and system

Technical Field

The embodiments of the present application relate to the field of communication technology, and in particular, to a clock synchronization method, device and system.

Background Art

Network communication provides convenient services for information exchange and sharing in people's daily life and work. With the increasing business applications, network traffic and connected devices, the complexity and heterogeneity of the network are becoming more and more prominent. For example, the differences in computing, storage and power supply resources of each node, the diversity of physical link types such as Ethernet, Bluetooth, WiFi, the complexity of star, tree, bus, hybrid and other networking structures, and the differences in node clock reading such as network card clock and system clock.

It is particularly important to design a clock synchronization method that can meet the clock synchronization requirements of complex network systems and network nodes in different network environments and with different configurations.

Summary of the invention

The embodiments of the present application provide a clock synchronization method, device and system, which can realize different clock synchronization requirements for nodes in different network environments and with different configurations in a heterogeneous network, determine different clock synchronization schemes, and reduce resource overhead in the system.

In a first aspect, a clock synchronization method is provided, comprising: a first node sends a subscription request message to a control node, wherein the subscription request message is used to subscribe to a clock synchronization service between the first node and a second node, and the second node is a node that performs clock synchronization with the first node; the control node determines a policy sending message based on the subscription request message, and the policy sending message includes a clock synchronization algorithm; the first node obtains clock synchronization parameters, and the clock synchronization parameters are used for the clock synchronization service, and the clock synchronization parameters are determined according to the clock synchronization algorithm.

In this embodiment, the control node can determine a suitable clock synchronization algorithm for the first node according to the subscription request message sent by the first node, so that the first node can obtain the clock synchronization parameters determined according to the clock synchronization algorithm and realize clock synchronization with the second node. The control node can determine different clock synchronization algorithms for the clock synchronization services between different nodes according to the differences between different nodes. In addition, the control node can also adjust the clock synchronization algorithm used according to the changes in dynamic factors such as real-time network load and communication quality. For example, for nodes with low configuration or weak computing and storage capabilities in the system, a clock synchronization algorithm with moderate requirements on the computing and storage capabilities of the node can be used on the premise of meeting the synchronization requirements of the node; for nodes with high requirements on synchronization accuracy, a more complex clock synchronization algorithm can be used, or the existing clock synchronization algorithm can be improved to reduce the clock synchronization error. Furthermore, the clock synchronization method provided in the embodiment of the present application can be applied to complex heterogeneous systems, achieve a smaller system load, and reduce the resource overhead of the system. For examples of the clock synchronization algorithm in this embodiment, please refer to Figures 2 and 9 to 11 and related introductions. For specific details of this embodiment and each step, please refer to the description in Figure 3. For the specific structure of the subscription request message, please refer to Figure 5 and related descriptions. For the specific structure of the policy delivery message, please refer to Figure 6 and related descriptions.

In combination with the first aspect, in certain implementations of the first aspect, the policy delivery message includes an identifier of an execution node, and the method further includes: the control node sends the policy delivery message to the execution node; the execution node executes the clock synchronization algorithm according to the policy delivery message, and the clock synchronization parameters are determined based on the time information of the synchronization message sent and/or received by the execution node when executing the clock synchronization algorithm, the time information includes the value or timestamp of the clock counter associated with the execution node sending the synchronization message, and/or the time information includes the value or timestamp of the clock counter associated with the execution node receiving the synchronization message.

In this embodiment, the control node determines the execution node that executes the clock synchronization algorithm. The execution node may include the first node and the second node, or the execution node may not include the first node and/or the second node. Exemplarily, the execution node may be determined by the control node according to the clock synchronization accuracy requirements of the first node and the second node, the hardware configuration of the first node and the second node, the communication status of the first node and the second node, etc. When the hardware configuration of the first node and the second node is high and has a certain message sending and receiving capability, the execution node may include the first node and the second node. On the contrary, when the configuration of the first node and the second node is low or the communication status is poor, the execution node may include other nodes in the network to reduce the clock synchronization overhead of the first node and the second node. The execution node is used to execute the clock synchronization algorithm, and the clock synchronization parameter can be determined according to the time information in the process of executing the clock synchronization algorithm by the execution node. The timestamp or the value of the clock counter associated with the execution node sending or receiving the synchronization message may correspond to the time when the synchronization message is sent, and the timestamp or the value of the clock counter may be read or marked before, when or after the sending node of the synchronization message is sent, or may be read or marked when or after the receiving node of the synchronization message receives the synchronization message. The value of the clock counter can be read, for example, by the TSF clock (also referred to as the TSF counter) mentioned later, and the timestamp can be read, for example, by the system clock mentioned later, and the value and timestamp of the clock counter can also be read by other clocks, which is not limited in this application. The process of executing the clock synchronization algorithm by the execution node in this embodiment can refer to the relevant descriptions of Figures 2 to 3 and Figures 9 to 11.

In combination with the first aspect, in certain implementations of the first aspect, the policy delivery message also includes an identifier of a convergence node, and the convergence node is not the first node. Before the first node obtains the clock synchronization parameters, the method also includes: the control node sends the policy delivery message to the convergence node; the execution node sends a time information upload message to the convergence node, and the time information upload message includes the time information; the convergence node determines the clock synchronization parameters based on the clock synchronization algorithm and the time information; the convergence node sends a parameter release message to the first node, and the parameter release message includes the clock synchronization parameters.

In this embodiment, the control node will also determine the convergence node, which may not be the same node as the first node, and the convergence node determines the clock synchronization parameters according to the clock synchronization algorithm and the message sending/receiving time information during the execution of the clock synchronization algorithm by the execution node. In this application, the convergence node determined by the control node calculates the clock synchronization parameters. The convergence node can exemplarily have a high computing and storage capacity, so that the control node can determine the convergence node according to the computational complexity of the determined clock synchronization algorithm and the configuration, computing and storage capacity of the nodes in the system. In this way, the burden on nodes with weak computing and storage capabilities can be reduced, the adverse effects of clock synchronization on normal network services can be avoided, and the robustness of clock synchronization can be improved. The specific structure of the time information upload message in this embodiment can refer to Figure 7 and related descriptions, and the specific structure of the parameter release message can refer to Figure 8 and related descriptions.

After calculating the clock synchronization parameter, the sink node directly sends the clock synchronization parameter to the first node, so that the first node can adjust its clock value accordingly.

In combination with the first aspect, in certain implementations of the first aspect, the policy delivery message also includes an identifier of a convergence node, and the convergence node is not the first node. Before the first node obtains the clock synchronization parameters, the method also includes: the control node sends the policy delivery message to the convergence node; the execution node sends a time information upload message to the convergence node, and the time information upload message includes the time information; the convergence node determines the clock synchronization parameters based on the clock synchronization algorithm and the time information; the convergence node sends the clock synchronization parameters to the control node; the control node sends a parameter release message to the first node, and the parameter release message includes the clock synchronization parameters.

In this embodiment, the control node determines the aggregation node, and after the aggregation node calculates the clock synchronization parameter, the clock synchronization parameter is sent to the control node, and the control node carries the clock synchronization parameter in the parameter release message and sends it to the first node, so that the first node can adjust the clock value accordingly. The routing path from the aggregation node to the first node is longer than the routing path from the control node to the first node, so that the control node can assist in the release of the clock synchronization parameter. The specific structure of the time information upload message in this embodiment can refer to Figure 7 and related descriptions, and the specific structure of the parameter release message can refer to Figure 8 and related descriptions.

In combination with the first aspect, in some implementations of the first aspect, the policy sending message also includes an identifier of a convergence node, and the convergence node is the first node. Before the first node obtains the clock synchronization parameters, the method also includes: the execution node sends a time information upload message to the convergence node, and the time information upload message includes the time information; the first node obtains the clock synchronization parameters, including: the first node determines the clock synchronization parameters based on the time information.

In this embodiment, when the first node has higher computing and storage capabilities, the control node may determine the aggregation node as the first node, and after the execution node executes the clock synchronization algorithm, the corresponding time information may be sent to the first node to calculate the clock synchronization parameters.

In combination with the first aspect, in some implementations of the first aspect, the subscription request message includes an identifier of the first node, an identifier of the second node, and a clock synchronization accuracy.

In this embodiment, the subscription request message includes the identifiers of the first node and the second node and the clock synchronization accuracy, so that the control node can determine the appropriate clock synchronization algorithm according to the synchronization requirements carried in the subscription request message and the communication medium information of the first node and the second node determined by the control node. Optionally, the subscription request message may also include the communication medium type of the first node, the first node's requirements for clock synchronization service performance and synchronization process execution, such as clock synchronization period, clock synchronization convergence speed, time information marking method, synchronization message processing priority, etc.

In combination with the first aspect, in certain implementation methods of the first aspect, the policy-sent message also includes at least one of the following: a first clock synchronization cycle, the type of the synchronization message, the communication medium used for transmission of the synchronization message, and a time information marking method of the synchronization message, wherein the first clock synchronization cycle is the period in which the execution node executes the clock synchronization algorithm.

The control node may determine the first clock synchronization period, for example, based on factors such as the available remaining power of the first node and the second node, network resource usage, and communication conditions. The control node may also determine the type of synchronization message, the communication medium used for synchronization message transmission, and the time information marking method.

In combination with the first aspect, in some implementations of the first aspect, the method further includes: the control node determines a second clock synchronization period according to the length of the confidence interval of the clock value of the first node and the clock synchronization accuracy; or, the control node determines the second clock synchronization period according to the length of the confidence interval of the clock value of the second node and the clock synchronization accuracy; wherein the confidence interval of the clock value of the first node or the confidence interval of the clock value of the second node is determined by the convergence node according to the clock synchronization parameter; the control node sends the second clock synchronization period to the execution node; the execution node executes the clock synchronization algorithm according to the second clock synchronization period; wherein, when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the first clock synchronization period is the second clock synchronization period; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than the first preset threshold and the length of the confidence interval is greater than the clock synchronization accuracy, the second clock synchronization period is less than the first clock synchronization period, and when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than the first preset threshold and the length of the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period.

In this embodiment, the control node can update the clock synchronization period according to the network resource usage and communication conditions, and the control node can adjust the clock synchronization period according to the clock synchronization accuracy required by the first node and the length of the confidence interval of the clock value of the first node. While meeting the clock synchronization accuracy requirement of the first node, the overall overhead of clock synchronization is reduced.

Optionally, after determining the second synchronization period, the control node may update the communication medium used for synchronization message transmission, the time information marking method of the synchronization message, the type of synchronization message, etc. based on network resource usage and network node load.

In combination with the first aspect, in some implementations of the first aspect, the method further includes: the control node determines a second clock synchronization period according to the length of the confidence interval of the clock value of the first node and the clock synchronization accuracy; or, the control node determines the second clock synchronization period according to the length of the confidence interval of the clock value of the second node and the clock synchronization accuracy; wherein the confidence interval of the clock value of the first node or the confidence interval of the clock value of the second node is determined by the convergence node according to the clock synchronization parameter; the control node sends the second clock synchronization period to the execution node; the execution node executes the clock synchronization algorithm according to the second clock synchronization period; wherein, when the length of the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period; when the length of the confidence interval is greater than the clock synchronization accuracy and the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the second clock synchronization period is the first clock synchronization period; when the length of the confidence interval is greater than the clock synchronization accuracy and the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold, the second clock synchronization period is less than the first clock synchronization period.

In this embodiment, in order to reduce the system overhead, when the length of the confidence interval is less than the clock synchronization accuracy, the clock synchronization period is increased. When the length of the confidence interval is greater than the clock synchronization accuracy and the absolute value of the difference between the two is greater than the first preset threshold, the clock synchronization period is reduced to meet the clock synchronization accuracy requirements of the nodes that need the clock synchronization service.

In combination with the first aspect, in certain implementations of the first aspect, the execution node includes the first node and the second node, the first node and the second node are located in different local area networks, the time information includes the TSF reception time of the first synchronization message and the TSF sending time of the first synchronization message, the TSF reception time of the second synchronization message, and the TSF sending time of the second synchronization message; the clock synchronization parameters include at least one of the following: the difference between the TSF clock value of the first node and the TSF clock value of the second node and the difference between the TSF clock frequency of the first node and the TSF clock frequency of the second node; wherein, the execution node executes the clock synchronization algorithm, including: the first node aligns the TSF clock of the first node with the system clock of the first node; the first node sends the first synchronization message to the second node; the second node sends the second synchronization message to the first node; the second node adjusts the TSF clock of the second node according to the clock synchronization parameters; the second node adjusts the system clock of the second node according to the adjusted TSF clock.

In this embodiment, when the first node and the second node are in different local area networks, the traditional clock synchronization algorithm based on WiFi TSF cannot be used. The embodiment of the present application improves the clock synchronization algorithm, and realizes the clock alignment of two nodes in different local area networks by aligning the system clock of the first node with the TSF clock-aligning the TSF clock of the second node to the TSF clock of the first node-aligning the system clock of the second node to the TSF clock of the second node, so that the clock synchronization algorithm provided by the embodiment of the present application has a wider scope of application. In this embodiment, the TSF sending time of the first synchronization message and the TSF receiving time of the second synchronization message refer to the TSF clock value when the first node sends the first synchronization message and receives the second synchronization message after synchronizing the system clock and the TSF clock, and the difference between the TSF clock value of the first node and the TSF clock value of the second node and the difference between the TSF clock frequency of the first node and the TSF clock frequency of the second node are also based on the clock offset value and clock frequency deviation of the TSF clock after the first node synchronizes the system clock and the TSF clock with the TSF clock of the second node. The specific details of this embodiment can be referred to Figure 11 and related descriptions.

Optionally, the clock synchronization between the first node and the second node can be achieved by first aligning the system clock and the TSF clock of the second node, then aligning the TSF clock of the first node to the TSF clock of the second node, and finally aligning the system clock of the first node to the TSF clock of the first node.

In combination with the first aspect, in some implementations of the first aspect, the execution node includes the first node, the second node and the third node, and the time information includes: the time when the first node receives multiple reference messages and the time when the second node receives the multiple reference messages; the clock synchronization parameters include at least one of the following: the difference between the clock value of the first node and the clock value of the second node and the difference between the clock frequency of the first node and the clock frequency of the second node; or, the clock synchronization parameters include at least one of the following: the difference between the clock value of the first node and the first reference clock value, the difference between the clock value of the second node and the first reference clock value, the difference between the clock frequency of the first node and the first reference clock frequency, and the difference between the clock frequency of the second node and the first reference clock frequency; wherein, the execution node executes the clock synchronization algorithm including: the third node sends the multiple reference messages to the first node and the second node.

In this embodiment, when the clocks of the first node and the second node are synchronized, the control node additionally selects a third node, and the third node sends multiple reference messages to the first node and the second node. The first node and the second node upload the reception time of the multiple reference messages to the aggregation node, and the time of receiving the multiple reference messages can be represented by the numerical value of the timestamp or the clock counter, so that the aggregation node calculates the clock synchronization parameters of the first node and the second node. The clock synchronization algorithm provided in the embodiment of the present application performs the clock synchronization process in the form of unidirectional message transmission, which can reduce the error caused by the asymmetric round-trip delay of the message in the traditional two-way message interaction process, and can shield the uncertainty of the protocol stack communication such as message encapsulation and channel access and the system scheduling processing delay, and can improve the clock synchronization accuracy. For specific details of this embodiment, please refer to Figure 10 and its related description.

In combination with the first aspect, in certain implementations of the first aspect, the time information also includes sending times of the multiple reference messages.

In combination with the first aspect, in certain implementations of the first aspect, the execution node does not include the first node, the clock synchronization parameters include a second reference clock value and/or a second reference clock frequency, and the method further includes: the first node updates the clock of the first node to the second reference clock value and/or the second reference clock frequency based on the clock synchronization parameters.

In this embodiment, the node for executing the clock synchronization algorithm determined by the control node does not include the first node, but selects a node with richer storage and computing capabilities as the execution node. These nodes can continuously execute a variety of different clock synchronization algorithms to form a local clock synchronization domain. The time information can be uploaded by these execution nodes to the convergence node to calculate the clock synchronization parameters, and then the convergence node sends the clock synchronization parameters to the control node. The control node can determine the calibrated second reference clock value and/or second reference clock frequency, and send the second reference clock value and/or second reference clock frequency to the first node, thereby realizing the clock synchronization of the first node and the second node. The second reference clock value and/or the second reference clock frequency can also be sent to the second node, so that the second node can also adjust the local system clock to the second reference clock value and/or the second reference clock frequency, thereby realizing the clock synchronization of the first node and the second node. When the first node and the second node do not need clock synchronization, the subscription of the clock synchronization service can be canceled. The clock synchronization scheme provided in the embodiment of the present application can avoid the deployment of special equipment, get rid of the limitations of specific module installation and networking topology, so that the clock synchronization operation can be conveniently performed to realize the clock synchronization of nodes with extremely limited computing and storage capabilities.

In a second aspect, a clock synchronization method is provided, including: a first node sends a subscription request message to a control node, the subscription request message is used to subscribe to the clock synchronization service of the first node and a second node, and the second node is a node that performs clock synchronization with the first node; the first node receives a policy delivery message from the control node, the policy delivery message is determined by the control node according to the subscription request message, the policy delivery message includes a clock synchronization algorithm and an identifier of an execution node, and the execution node includes the first node and the second node; the first node executes the clock synchronization algorithm according to the policy delivery message; the first node obtains clock synchronization parameters, the clock synchronization parameters are used for the clock synchronization service, and the clock synchronization parameters are determined according to the clock synchronization algorithm.

In combination with the second aspect, in certain implementations of the second aspect, the policy delivery message also includes an identifier of a convergence node, and the convergence node is not the first node. The method also includes: the first node sends a time information upload message to the convergence node, and the time information upload message includes time information, and the time information is used by the convergence node to determine the clock synchronization parameters, and the time information includes a value or timestamp of a clock counter associated with the execution node executing the clock synchronization algorithm to send a synchronization message, and/or, the time information includes a value or timestamp of a clock counter associated with the execution node executing the clock synchronization algorithm to receive the synchronization message; the first node receives a parameter release message from the convergence node or the control node, and the parameter release message includes the clock synchronization parameters.

In combination with the second aspect, in some implementations of the second aspect, the subscription request message includes an identifier of the first node, an identifier of the second node, and a clock synchronization accuracy.

In combination with the second aspect, in certain implementation methods of the second aspect, the policy-sent message also includes at least one of the following: a first clock synchronization cycle, the type of the synchronization message, the communication medium used for transmission of the synchronization message, and a time information marking method of the synchronization message, wherein the first clock synchronization cycle is the period in which the execution node executes the clock synchronization algorithm.

In combination with the second aspect, in some implementations of the second aspect, the method further includes: the first node receives a second clock synchronization cycle from the control node; the first node executes the clock synchronization algorithm according to the second clock synchronization cycle; wherein the second clock synchronization cycle is determined by the control node according to the length of the confidence interval of the clock value of the first node and the synchronization accuracy, or the second clock synchronization cycle is determined by the control node according to the length of the confidence interval of the clock value of the second node and the synchronization accuracy; the confidence interval of the clock value of the first node or the confidence interval of the clock value of the second node is determined by the convergence node according to the clock synchronization parameter; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the first clock synchronization cycle is the second clock synchronization cycle; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than the first preset threshold and the length of the confidence interval is greater than the clock synchronization accuracy, the second clock synchronization cycle is less than the first clock synchronization cycle, and when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than the first preset threshold and the length of the confidence interval is less than the clock synchronization accuracy, the second synchronization cycle is greater than the first clock synchronization cycle. In combination with the second aspect, in some implementations of the second aspect, the method further includes: the first node receives a second clock synchronization cycle from the control node; the first node executes the clock synchronization algorithm according to the second clock synchronization cycle; wherein the second clock synchronization cycle is determined by the control node according to the length of the confidence interval of the clock value of the first node and the synchronization accuracy, or the second clock synchronization cycle is determined by the control node according to the length of the confidence interval of the clock value of the second node and the synchronization accuracy; the confidence interval of the clock value of the first node or the confidence interval of the clock value of the second node is determined by the convergence node according to the clock synchronization parameter; wherein, when the length of the confidence interval is less than the clock synchronization accuracy, the second synchronization cycle is greater than the first clock synchronization cycle; when the length of the confidence interval is greater than the clock synchronization accuracy and the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the second clock synchronization cycle is the first clock synchronization cycle; when the length of the confidence interval is greater than the clock synchronization accuracy and the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold, the second clock synchronization cycle is less than the first clock synchronization cycle.

In combination with the second aspect, in certain implementations of the second aspect, the first node and the second node are located in different local area networks, and the time information includes the TSF reception time of the first synchronization message and the TSF sending time of the first synchronization message, the TSF reception time of the second synchronization message, and the TSF sending time of the second synchronization message; the clock synchronization parameters include at least one of the following: the difference between the TSF clock value of the first node and the TSF clock value of the second node and the difference between the TSF clock frequency of the first node and the TSF clock frequency of the second node; the first node executes the clock synchronization algorithm including: the first node receives the first synchronization message from the second node; the first node sends the second synchronization message to the second node; the first node adjusts the TSF clock of the first node according to the clock synchronization parameters; the first node adjusts the system clock of the first node according to the adjusted TSF clock.

In combination with the second aspect, in some implementations of the second aspect, the execution node also includes a third node, and the time information includes: the time when the first node receives the multiple reference messages and the time when the second node receives the multiple reference messages; the clock synchronization parameters include at least one of the following: the difference between the clock value of the first node and the clock value of the second node and the difference between the clock frequency of the first node and the clock frequency of the second node; or, the clock synchronization parameters include at least one of the following: the difference between the clock value of the first node and the first reference clock value, the difference between the clock value of the second node and the first reference clock value, the difference between the clock frequency of the first node and the first reference clock frequency, and the difference between the clock frequency of the second node and the first reference clock frequency; wherein, the first node executes the clock synchronization algorithm including: the first node receives the multiple reference messages from the third node.

In combination with the second aspect, in certain implementations of the second aspect, the time information also includes sending times of the multiple reference messages.

According to a third aspect, a clock synchronization method is provided, comprising: a control node receives a subscription request message from a first node, the subscription request message is used to subscribe to a clock synchronization service between the first node and a second node, the second node being a node that performs clock synchronization with the first node; the control node determines a policy sending message based on the subscription request message, the policy sending message is used to determine clock synchronization parameters, and the clock synchronization parameters are used for the clock synchronization service.

In combination with the third aspect, in certain implementations of the third aspect, the policy delivery message includes an identifier of a clock synchronization algorithm and an execution node, and the method further includes: the control node sends the policy delivery message to the execution node so that the execution node obtains time information during the execution of the clock synchronization algorithm, the time information includes the value or timestamp of the clock counter associated with the execution node sending the synchronization message, and/or the time information includes the value or timestamp of the clock counter associated with the execution node receiving the synchronization message.

In combination with the third aspect, in certain implementations of the third aspect, the policy delivery message also includes an identifier of the aggregation node, and the clock synchronization parameter is determined by the aggregation node based on the time information obtained from the execution node; the method also includes: the control node sending the policy delivery message to the aggregation node.

In combination with the third aspect, in certain implementations of the third aspect, the method further includes: the control node receiving the clock synchronization parameters from the aggregation node; the control node sending a parameter publishing message to the first node, and the parameter publishing message includes the clock synchronization parameters.

In combination with the third aspect, in certain implementations of the third aspect, the subscription request message includes an identifier of the first node, an identifier of the second node, and a clock synchronization accuracy.

In combination with the third aspect, in certain implementations of the third aspect, the subscription request message also includes at least one of the following: a first clock synchronization cycle, the type of the synchronization message, the communication medium used for transmission of the synchronization message, and a time information marking method of the synchronization message, wherein the first clock synchronization cycle is the period in which the execution node executes the clock synchronization algorithm.

In combination with the third aspect, in certain implementations of the third aspect, the method further includes: the control node determines the second clock synchronization period according to the length of the confidence interval of the clock value of the first node and the clock synchronization accuracy, or the control node determines the second clock synchronization period according to the length of the confidence interval of the clock value of the second node and the clock synchronization accuracy, and the confidence interval of the clock value of the first node or the confidence interval of the clock value of the second node is determined according to the clock synchronization parameter; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the first clock synchronization period is the second clock synchronization period; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold and the length of the confidence interval is greater than the clock synchronization accuracy, the second clock synchronization period is less than the first clock synchronization period, and when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than the first preset threshold and the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period.

In combination with the third aspect, in certain implementations of the third aspect, the method further includes: the control node determines the second clock synchronization period based on the length of the confidence interval of the clock value of the first node and the clock synchronization accuracy, or the control node determines the second clock synchronization period based on the length of the confidence interval of the clock value of the second node and the clock synchronization accuracy, and the confidence interval of the clock value of the first node or the confidence interval of the clock value of the second node is determined based on the clock synchronization parameter; wherein, when the length of the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period; when the length of the confidence interval is greater than the clock synchronization accuracy and the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the second clock synchronization period is the first clock synchronization period; when the length of the confidence interval is greater than the clock synchronization accuracy and the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold, the second clock synchronization period is less than the first clock synchronization period.

In a fourth aspect, a clock synchronization method is provided, comprising: a convergence node receives a policy delivery message from a control node, the policy delivery message is determined by the control node based on a subscription request message sent by a first node, the subscription request message is used to subscribe to the clock synchronization services of the first node and the second node, the policy delivery message includes a clock synchronization algorithm, an identifier of an execution node and an identifier of the convergence node; the convergence node receives a time information upload message from an execution node, the time information upload message includes time information, the time information includes a value or timestamp of a clock counter associated with the execution node sending the synchronization message, and/or the time information includes a value or timestamp of a clock counter associated with the execution node receiving the synchronization message; the convergence node determines clock synchronization parameters based on the clock synchronization algorithm and the time information, and the clock synchronization parameters are used for the clock synchronization service.

In combination with the fourth aspect, in some implementations of the fourth aspect, the aggregation node is not the first node, and the method further includes: the aggregation node sends a parameter publishing message to the first node, and the parameter publishing message includes the clock synchronization parameter.

In combination with the fourth aspect, in certain implementations of the fourth aspect, the aggregation node is not the first node, and the method also includes: the aggregation node sends the clock synchronization parameters to the control node so that the control node sends a parameter release message to the first node, and the parameter release message includes the clock synchronization parameters.

In combination with the fourth aspect, in certain implementations of the fourth aspect, the subscription request message includes an identifier of the first node, an identifier of the second node, and a clock synchronization accuracy.

In combination with the fourth aspect, in certain implementation methods of the fourth aspect, the policy-sent message also includes at least one of the following: a first clock synchronization cycle, the type of the synchronization message, the communication medium used for transmission of the synchronization message, and a time information marking method of the synchronization message, wherein the first clock synchronization cycle is the period in which the execution node executes the clock synchronization algorithm.

In combination with the fourth aspect, in certain implementations of the fourth aspect, the method further includes: the aggregation node determines the confidence interval of the clock value of the first node and/or the confidence interval of the clock value of the second node based on the clock synchronization parameter, and the aggregation node sends the confidence interval to the control node so that the control node determines the second clock synchronization period based on the length of the confidence interval; wherein, when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the first clock synchronization period is the second clock synchronization period; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold and the length of the confidence interval is greater than the clock synchronization accuracy, the second clock synchronization period is less than the first clock synchronization period, and when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold and the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period.

In combination with the fourth aspect, in certain implementations of the fourth aspect, the method also includes: the aggregation node determines the confidence interval of the clock value of the first node and/or the confidence interval of the clock value of the second node based on the clock synchronization parameters, and the aggregation node sends the confidence interval to the control node so that the control node determines the second clock synchronization period based on the length of the confidence interval; wherein, when the length of the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period; when the length of the confidence interval is greater than the clock synchronization accuracy and the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the second clock synchronization period is the first clock synchronization period; when the length of the confidence interval is greater than the clock synchronization accuracy and the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold, the second clock synchronization period is less than the first clock synchronization period.

In a fifth aspect, a clock synchronization system is provided, comprising: a first node, used to send a subscription request message to the control node, the subscription request message is used to subscribe to the clock synchronization service of the first node and a second node, the second node is a node that performs clock synchronization with the first node; a control node, used to determine a policy sending message based on the subscription request message, the policy sending message includes a clock synchronization algorithm; the first node is also used to obtain clock synchronization parameters, the clock synchronization parameters are used for the clock synchronization service, and the clock synchronization parameters are determined based on the clock synchronization algorithm.

In combination with the fifth aspect, in certain implementations of the fifth aspect, the policy sending message includes an identifier of an execution node, and the system also includes an execution node; the control node is also used to send the policy sending message to the execution node; the execution node is used to execute the clock synchronization algorithm according to the policy sending message, and the clock synchronization parameters are determined based on the time information of the synchronization message sent and/or received by the execution node when executing the clock synchronization algorithm, and the time information includes the value or timestamp of the clock counter associated with the execution node sending the synchronization message, and/or the time information includes the value or timestamp of the clock counter associated with the execution node receiving the synchronization message.

In combination with the fifth aspect, in certain implementation methods of the fifth aspect, the policy delivery message also includes an identifier of a convergence node, the convergence node is not the first node, and the system also includes a convergence node; the control node is also used to send the policy delivery message to the convergence node; the execution node is also used to send a time information upload message to the convergence node, and the time information upload message includes the time information; the convergence node is used to: determine the clock synchronization parameters based on the time information and the clock synchronization algorithm; send a parameter release message to the first node, and the parameter release message includes the clock synchronization parameters.

In combination with the fifth aspect, in certain implementations of the fifth aspect, the policy delivery message also includes an identifier of a convergence node, the convergence node is not the first node, and the system also includes a convergence node; the control node is also used to send the policy delivery message to the convergence node; the execution node is also used to send a time information upload message to the convergence node, and the time information upload message includes the time information; the convergence node is used to: determine the clock synchronization parameters based on the time information and the clock synchronization algorithm; send the clock synchronization parameters to the control node; the control node is also used to send a parameter release message to the first node, and the parameter release message includes the clock synchronization parameters.

In combination with the fifth aspect, in certain implementation methods of the fifth aspect, the policy sending message also includes an identifier of a convergence node, and the convergence node is the first node; the execution node is also used to send a time information upload message to the convergence node, and the time information upload message includes the time information; the first node is specifically used to: determine the clock synchronization parameters based on the time information.

In combination with the fifth aspect, in certain implementations of the fifth aspect, the subscription request message includes the identifier of the first node, the identifier of the second node, and the clock synchronization accuracy.

In combination with the fifth aspect, in certain implementation methods of the fifth aspect, the policy-sent message also includes at least one of the following: a first clock synchronization cycle, the type of the synchronization message, the communication medium used for transmission of the synchronization message, and a time information marking method of the synchronization message, wherein the first clock synchronization cycle is the period in which the execution node executes the clock synchronization algorithm.

In combination with the fifth aspect, in certain implementations of the fifth aspect, the control node is further used to: determine the second clock synchronization period according to the length of the confidence interval of the clock value of the first node and the clock synchronization accuracy, or determine the second clock synchronization period according to the length of the confidence interval of the clock value of the second node and the clock synchronization accuracy, the confidence interval of the clock value of the first node or the confidence interval of the second node is determined by the aggregation node according to the clock synchronization parameter; send the second clock synchronization period to the execution node; the execution node is further used to execute the clock synchronization algorithm according to the second clock synchronization period; wherein, when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the first clock synchronization period is the second clock synchronization period; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than the first preset threshold and the length of the confidence interval is greater than the clock synchronization accuracy, the second clock synchronization period is less than the first clock synchronization period; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than the first preset threshold and the length of the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period.

In combination with the fifth aspect, in certain implementations of the fifth aspect, the control node is further used to: determine a second clock synchronization period based on the length of a confidence interval of the clock value of the first node and the clock synchronization accuracy, or determine the second clock synchronization period based on the length of a confidence interval of the clock value of the second node and the clock synchronization accuracy, the confidence interval of the clock value of the first node or the confidence interval of the second node being determined by the aggregation node based on the clock synchronization parameters; send the second clock synchronization period to the execution node; the execution node is further used to execute the clock synchronization algorithm based on the second clock synchronization period; wherein, when the length of the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period; when the length of the confidence interval is greater than the clock synchronization accuracy and the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the second clock synchronization period is the first clock synchronization period; when the length of the confidence interval is greater than the clock synchronization accuracy and the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold, the second clock synchronization period is less than the first clock synchronization period.

In combination with the fifth aspect, in certain implementations of the fifth aspect, the execution node includes the first node and the second node, the first node and the second node are located in different local area networks, the time information includes the TSF reception time of the first synchronization message and the TSF sending time of the first synchronization message, the TSF reception time of the second synchronization message, and the TSF sending time of the second synchronization message; the clock synchronization parameters include at least one of the following: the difference between the TSF clock value of the first node and the TSF clock value of the second node and the difference between the TSF clock frequency of the first node and the TSF clock frequency of the second node; the first node is specifically used to: align the TSF clock of the first node with the system clock of the first node; send the first synchronization message to the second node; the second node is specifically used to: send the second synchronization message to the first node; adjust the TSF clock of the second node according to the clock synchronization parameters; adjust the system clock of the second node according to the adjusted TSF clock.

In combination with the fifth aspect, in certain implementations of the fifth aspect, the execution nodes include the first node, the second node and the third node, and the time information includes: the time when the first node receives the multiple reference messages and the time when the second node receives the multiple reference messages; the clock synchronization parameters include at least one of the following: the difference between the clock value of the first node and the clock value of the second node and the difference between the clock frequency of the first node and the clock frequency of the second node; or, the clock synchronization parameters include at least one of the following: the difference between the clock value of the first node and the first reference clock value, the difference between the clock value of the second node and the first reference clock value, the difference between the clock frequency of the first node and the first reference clock frequency, and the difference between the clock frequency of the second node and the first reference clock frequency; wherein the third node is specifically used to send the multiple reference messages to the first node and the second node.

In combination with the fifth aspect, in certain implementations of the fifth aspect, the time information also includes the sending time of the multiple reference messages.

In combination with the fifth aspect, in certain implementations of the fifth aspect, the execution node does not include the first node, the clock synchronization parameters include a second reference clock value and a second reference clock frequency, and the first node is further used to: update the clock of the first node to the second reference clock value and/or the second reference clock frequency according to the clock synchronization parameters.

In a sixth aspect, a clock synchronization device is provided, which is a first node and includes: a transceiver unit, used to send a subscription request message to a control node, wherein the subscription request message is used to subscribe to the clock synchronization service of the first node and the second node, and the second node is a node that performs clock synchronization with the first node; the transceiver unit is also used to receive a policy message from the control node, wherein the policy message is determined by the control node according to the subscription request message, and the policy message includes a clock synchronization algorithm and an identifier of an execution node, and the execution node includes a first node and the second node; a processing unit, used to execute the clock synchronization algorithm according to the policy message; the transceiver unit is also used to obtain clock synchronization parameters, wherein the clock synchronization parameters are used for the clock synchronization service, and the clock synchronization parameters are determined according to the clock synchronization algorithm.

In combination with the sixth aspect, in certain implementation methods of the sixth aspect, the policy sending message also includes an identifier of a convergence node, and the convergence node is not the first node. The transceiver unit is also used to: send a time information upload message to the convergence node, the time information upload message includes time information, and the time information is used by the convergence node to determine the clock synchronization parameters, the time information includes the value or timestamp of the clock counter associated with the execution node executing the clock synchronization algorithm to send the synchronization message, and/or the time information includes the value or timestamp of the clock counter associated with the execution node executing the clock synchronization algorithm to receive the synchronization message; receive a parameter release message from the convergence node, and the parameter release message includes the clock synchronization parameters.

In combination with the sixth aspect, in certain implementations of the sixth aspect, the subscription request message includes the identifier of the first node, the identifier of the second node, and the clock synchronization accuracy.

In combination with the sixth aspect, in certain implementation methods of the sixth aspect, the policy-sent message also includes at least one of the following: a first clock synchronization cycle, the type of the synchronization message, the communication medium used for transmission of the synchronization message, and a time information marking method of the synchronization message, wherein the first clock synchronization cycle is the period in which the execution node executes the clock synchronization algorithm.

In combination with the sixth aspect, in certain implementations of the sixth aspect, the transceiver unit is further used to: receive a second clock synchronization period from the control node; the processing unit is further used to execute the clock synchronization algorithm according to the second clock synchronization period; wherein the second clock synchronization period is determined by the control node according to the length of the confidence interval of the clock value of the first node and the clock synchronization accuracy, or the second clock synchronization period is determined by the control node according to the length of the confidence interval of the clock value of the second node and the clock synchronization accuracy; the confidence interval of the clock value of the first node and the confidence interval of the clock value of the second node are the aggregation node Determined according to the clock synchronization parameters; wherein, when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the first clock synchronization period is the second clock synchronization period; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold and the length of the confidence interval is greater than the clock synchronization accuracy, the second clock synchronization period is less than the first clock synchronization period; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold and the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period.

In combination with the sixth aspect, in certain implementations of the sixth aspect, the transceiver unit is further used to: receive a second clock synchronization period from the control node; the processing unit is further used to execute the clock synchronization algorithm according to the second clock synchronization period; wherein the second clock synchronization period is determined by the control node according to the length of the confidence interval of the clock value of the first node and the clock synchronization accuracy, or the second clock synchronization period is determined by the control node according to the length of the confidence interval of the clock value of the second node and the clock synchronization accuracy; the confidence interval of the clock value of the first node and the confidence interval of the clock value of the second node are determined by the aggregation node according to the clock synchronization parameters; wherein, when the length of the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period; when the length of the confidence interval is greater than the clock synchronization accuracy and the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the second clock synchronization period is the first clock synchronization period; when the length of the confidence interval is greater than the clock synchronization accuracy and the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold, the second clock synchronization period is less than the first clock synchronization period.

In combination with the sixth aspect, in certain implementations of the sixth aspect, the first node and the second node are located in different local area networks, and the time information includes the TSF reception time of the first synchronization message and the TSF sending time of the first synchronization message, the TSF reception time of the second synchronization message, and the TSF sending time of the second synchronization message; the clock synchronization parameters include at least one of the following: the difference between the TSF clock value of the first node and the TSF clock value of the second node and the difference between the TSF clock frequency of the first node and the TSF clock frequency of the second node; the first node executes the clock synchronization algorithm including: the first node receives the first synchronization message from the second node; the first node sends the second synchronization message to the second node; the first node adjusts the TSF clock of the first node according to the clock synchronization parameters; the first node adjusts the system clock of the first node according to the adjusted TSF clock.

In combination with the sixth aspect, in certain implementations of the sixth aspect, the execution node also includes a third node, and the time information includes: the timestamp of the first node receiving the multiple reference messages and the time when the second node receives the multiple reference messages; the clock synchronization parameters include at least one of the following: the difference between the clock value of the first node and the clock value of the second node and the difference between the clock frequency of the first node and the clock frequency of the second node; or, the clock synchronization parameters include at least one of the following: the difference between the clock value of the first node and the first reference clock value, the difference between the clock value of the second node and the first reference clock value, the difference between the clock frequency of the first node and the first reference clock frequency, and the difference between the clock frequency of the second node and the first reference clock frequency; wherein the processing unit includes a second transceiver subunit for receiving the multiple reference messages from the third node.

In combination with the sixth aspect, in certain implementations of the sixth aspect, the time information also includes the sending time of the multiple reference messages.

In the seventh aspect, a clock synchronization device is provided, which is a control node, and includes: a transceiver unit, used to receive a subscription request message from a first node, wherein the subscription request message is used to subscribe to the clock synchronization service of the first node and a second node, and the second node is a node that performs clock synchronization with the first node; a processing unit, used to determine a policy sending message based on the subscription request message, wherein the policy sending message is used to determine clock synchronization parameters, and the clock synchronization parameters are used for the clock synchronization service.

In combination with the seventh aspect, in certain implementation methods of the seventh aspect, the policy delivery message includes an identifier of a clock synchronization algorithm and an execution node, and the transceiver unit is further used to send the policy delivery message to the execution node so that the execution node can obtain time information during the execution of the clock synchronization algorithm, wherein the time information includes a value or timestamp of a clock counter associated with the execution node sending the synchronization message, and/or the time information includes a value or timestamp of a clock counter associated with the execution node receiving the synchronization message.

In combination with the seventh aspect, in certain implementation methods of the seventh aspect, the policy delivery message also includes an identifier of the aggregation node, and the clock synchronization parameter is determined by the aggregation node based on the time information obtained from the execution node; the transceiver unit is also used by the control node to send the policy delivery message to the aggregation node.

In combination with the seventh aspect, in certain implementations of the seventh aspect, the transceiver unit is further used to receive the clock synchronization parameters from the aggregation node; and send a parameter publishing message to the first node, wherein the parameter publishing message includes the clock synchronization parameters.

In combination with the seventh aspect, in certain implementations of the seventh aspect, the subscription request message includes the identifier of the first node, the identifier of the second node, and the clock synchronization accuracy.

In combination with the seventh aspect, in certain implementation methods of the seventh aspect, the policy-sent message also includes at least one of the following: a first clock synchronization cycle, the type of the synchronization message, the communication medium used for transmission of the synchronization message, and a time information marking method of the synchronization message, wherein the first clock synchronization cycle is the period in which the execution node executes the clock synchronization algorithm.

In combination with the seventh aspect, in certain implementations of the seventh aspect, the processing unit is further used to determine the second clock synchronization period based on the length of the confidence interval of the clock value of the first node and the clock synchronization accuracy, or to determine the second clock synchronization period based on the length of the confidence interval of the clock value of the second node and the clock synchronization accuracy, the confidence interval of the clock value of the first node or the confidence interval of the clock value of the second node is determined by the aggregation node according to the clock synchronization parameters; wherein, when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the first clock synchronization period is the second clock synchronization period; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold and the length of the confidence interval is greater than the clock synchronization accuracy, the second clock synchronization period is less than the first clock synchronization period; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold and the length of the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period.

In combination with the seventh aspect, in certain implementations of the seventh aspect, the processing unit is further used to determine the second clock synchronization period based on the length of the confidence interval of the clock value of the first node and the clock synchronization accuracy, or to determine the second clock synchronization period based on the length of the confidence interval of the clock value of the second node and the clock synchronization accuracy, the confidence interval of the clock value of the first node or the confidence interval of the clock value of the second node is determined by the aggregation node according to the clock synchronization parameters; wherein, when the length of the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period; when the length of the confidence interval is greater than the clock synchronization accuracy and the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the second clock synchronization period is the first clock synchronization period; when the length of the confidence interval is greater than the clock synchronization accuracy and the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold, the second clock synchronization period is less than the first clock synchronization period.

In an eighth aspect, a clock synchronization device is provided, which is a convergence node, and the clock synchronization device includes a transceiver unit, which is used to receive a policy message from a control node, and the policy message is determined by the control node according to a subscription request message sent by the first node, and the subscription request message is used to subscribe to the clock synchronization service of the first node and the second node, and the policy message includes a clock synchronization algorithm; receiving a time information upload message from an execution node, and the time information upload message includes time information, and the time information includes a value or timestamp of a clock counter associated with the execution node sending the synchronization message, and/or, the time information includes a value or timestamp of a clock counter associated with the execution node receiving the synchronization message; a processing unit, which is used to determine clock synchronization parameters according to the clock synchronization algorithm and the time information, and the clock synchronization parameters are used for the clock synchronization service.

In combination with the eighth aspect, in certain implementations of the eighth aspect, the aggregation node is not the first node, and the transceiver unit is further used to send a parameter publishing message to the first node, and the parameter publishing message includes the clock synchronization parameter.

In combination with the eighth aspect, in certain implementations of the eighth aspect, the transceiver unit is further used to send the clock synchronization parameter to the control node, so that the control node sends a parameter publishing message to the first node, and the parameter publishing message includes the clock synchronization parameter.

In combination with the eighth aspect, in certain implementations of the eighth aspect, the subscription request message includes the identifier of the first node, the identifier of the second node, and the clock synchronization accuracy.

In combination with the eighth aspect, in certain implementation methods of the eighth aspect, the policy-sent message also includes at least one of the following: a first clock synchronization cycle, the type of the synchronization message, the communication medium used for transmission of the synchronization message, and a time information marking method of the synchronization message, wherein the first clock synchronization cycle is the period in which the execution node executes the clock synchronization algorithm.

In combination with the eighth aspect, in certain implementations of the eighth aspect, the processing unit is further used to determine a confidence interval of the clock value of the first node or the second node based on the clock synchronization accuracy; the transceiver unit is further used to send the confidence interval of the clock value of the first node or the second node to the control node, so that the control node can determine a second clock synchronization period; wherein, when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the first clock synchronization period is the second clock synchronization period; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold and the length of the confidence interval is greater than the clock synchronization accuracy, the second clock synchronization period is less than the first clock synchronization period, and when the absolute value of the difference between the length d of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold and the length of the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period.

In combination with the eighth aspect, in certain implementations of the eighth aspect, the processing unit is further used to determine the confidence interval of the clock value of the first node or the second node based on the clock synchronization accuracy; the transceiver unit is further used to send the confidence interval of the clock value of the first node or the second node to the control node, so that the control node can determine a second clock synchronization period; wherein, when the length of the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period; when the length of the confidence interval is greater than the clock synchronization accuracy and the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the second clock synchronization period is the first clock synchronization period; when the length of the confidence interval is greater than the clock synchronization accuracy and the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold, the second clock synchronization period is less than the first clock synchronization period.

In a ninth aspect, a clock synchronization method is provided for a clock synchronization system, wherein the clock synchronization system comprises a first node, a second node and a third node, wherein the first node and the second node are nodes that require clock synchronization, and the method comprises: the third node sends R reference messages to the first node and the second node; based on time information, the clock offset value and/or clock frequency deviation of the first node and the second node is determined, wherein the time information includes the reception time of the R reference messages; and the first node and/or the second node performs clock synchronization based on the clock offset value and/or the clock frequency deviation.

In this embodiment, a reference message is sent by a third node to a first node and a second node that need clock synchronization, and the clock offset value and/or clock frequency deviation of the first node and the second node can be determined according to the reception time of the reference message. The clock offset value and/or clock frequency deviation can be determined by the first node, the second node, or the third node, or can be calculated by other nodes with strong computing or processing capabilities, and this application does not limit this.

The clock synchronization method provided in the embodiment of the present application performs the clock synchronization process in the form of unidirectional message transmission, which can reduce the error caused by the asymmetric round-trip delay of the traditional two-way message interaction process, and can shield the uncertainty of protocol stack communication such as message encapsulation and channel access and system scheduling processing delay, and can improve the clock synchronization accuracy. For specific details of this embodiment, please refer to Figure 10 and its related description.

In combination with the ninth aspect, in some implementations of the ninth aspect, when the clock frequency deviation of the first node and the second node is ignored and the uncertainty part of the message communication delay between the third node and the first node and the uncertainty part of the message communication delay between the third node and the second node satisfy a normal distribution, the clock offset value θ _offset of the first node and the second node satisfies the following formula:

Wherein, the T _2,i is the time when the first node receives the i-th reference message, and the T _3,i is the time when the second node receives the i-th reference message.

In combination with the ninth aspect, in certain implementations of the ninth aspect, the time information also includes the sending time of the reference message.

In combination with the ninth aspect, in some implementations of the ninth aspect, without ignoring the clock frequency deviation of the first node and the second node and the uncertainty part of the message communication delay between the third node and the first node and the uncertainty part of the message communication delay between the third node and the second node satisfy a normal distribution, the clock offset value θ _offset and the clock frequency deviation θ _skew of the first node and the second node satisfy the following formula:

x[i]＝T _2,i -T _3,i -μ

μ＝d ^KL -d ^KN

D _i = T _1,i -T _1,1

Among them, the T _2,i is the reception time of the i-th reference message by the first node L, the T _3,i is the reception time of the i-th reference message by the second node N, the T _1,i is the sending time of the i-th reference message by the third node K, the T _1,1 is the sending time of the first reference message by the third node, the d ^KL is the deterministic part of the message communication delay between the first node and the third node, and the d ^KN is the deterministic part of the message communication delay between the second node and the third node.

In the tenth aspect, a clock synchronization method is provided for clock synchronization of a first node and a second node, wherein the first node and the second node are located in different local area networks, and the method comprises: the first node aligns the TSF clock of the first node with the system clock of the first node; the first node sends a first synchronization message to the second node; the second node sends a second synchronization message to the first node; according to the TSF sending time of the first synchronization message, the TSF receiving time of the first synchronization message, the TSF sending time of the second synchronization message, and the TSF receiving time of the second synchronization message, the clock offset value and/or clock frequency deviation of the TSF clocks of the first node and the second node are determined; the second node adjusts the TSF clock of the second node according to the clock offset value and/or the clock frequency deviation; the second node adjusts the system clock of the second node according to the adjusted TSF clock.

In combination with the tenth aspect, in some implementations of the tenth aspect, while ignoring the clock frequency deviation between the first node and the second node and the difference in round-trip communication delay of the message between the first node and the second node, the clock offset value θ _offset of the TSF clock of the first node and the second node satisfies the following formula:

Among them, the T _1,i is the TSF receiving time of the first synchronization message, the T _0,i is the TSF sending time of the first synchronization message, the T _3,i is the TSF receiving time of the second synchronization message, and the T _2,i is the TSF sending time of the second synchronization message.

In combination with the tenth aspect, in some implementations of the tenth aspect, considering the difference in round-trip communication delay of the message between the first node and the second node, ignoring the clock frequency deviation of the first node and the second node and the uncertainty part of the message communication delay between the first node and the second node satisfying the normal distribution, the clock offset value θ _offset of the TSF clock of the first node and the second node satisfies the following formula:

Among them, the T _1,i is the TSF reception time of the first synchronization message during the i-th round of synchronization message interaction, the T _0,i is the TSF sending time of the first synchronization message during the i-th round of synchronization message interaction, the T _3,i is the TSF reception time of the second synchronization message during the i-th round of synchronization message interaction, the T _2,i is the TSF sending time of the second synchronization message during the i-th round of synchronization message interaction, and N is the interaction round of the synchronization message.

In combination with the tenth aspect, in some implementations of the tenth aspect, considering the difference in round-trip communication delay of the message between the first node and the second node, ignoring the clock frequency deviation of the first node and the second node and the uncertainty part of the message communication delay between the first node and the second node satisfying the exponential distribution, the clock offset value θ _offset of the TSF clock of the first node and the second node satisfies the following formula:

U _i = T _1,i - T _0,i

V _i = T _3,i - T _2,i

Among them, the T _1,i is the TSF reception time of the first synchronization message during the i-th round of synchronization message interaction, the T _0,i is the TSF sending time of the first synchronization message during the i-th round of synchronization message interaction, the T _3,i is the TSF reception time of the second synchronization message during the i-th round of synchronization message interaction, the T _2,i is the TSF sending time of the second synchronization message during the i-th round of synchronization message interaction, and N is the interaction round of the synchronization message.

In combination with the tenth aspect, in some implementations of the tenth aspect, considering that the difference in the round-trip communication delay of the message between the first node and the second node and the clock frequency deviation of the first node and the second node and the uncertainty part of the message communication delay between the first node and the second node satisfy the normal distribution, the clock offset value θ _offset and the clock frequency deviation θ _skew of the TSF clock of the first node and the second node satisfy the following formula:

Among them, the _T1 is the TSF receiving time of the first synchronization message during the i-th round of synchronization message interaction, the _T0 is the TSF sending time of the first synchronization message during the i-th round of synchronization message interaction, the _T3 is the TSF receiving time of the second synchronization message during the i-th round of synchronization message interaction, the _T2 is the TSF sending time of the second synchronization message during the i-th round of synchronization message interaction, and N is the interaction round of the synchronization message.

In the eleventh aspect, a clock synchronization device is provided, comprising at least one processor, wherein the processor is coupled to a memory, wherein the memory is used to store instructions, and when the instructions are executed by the processor, the processor executes a method as in the first aspect or any one of the implementations of the first aspect to the fourth aspect or any one of the implementations of the fourth aspect.

In the twelfth aspect, a computer-readable storage medium is provided, storing computer-executable instructions, which, when executed on a computer, cause the computer to execute a method such as causing the processor to execute the first aspect or any one of the implementations of the first aspect to the fourth aspect or any one of the implementations of the fourth aspect.

In the thirteenth aspect, a computer program product is provided, comprising: a computer program code, which, when executed, implements a method such as causing the processor to execute a method such as the first aspect or any one of the implementations of the first aspect to the fourth aspect or any one of the implementations of the fourth aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a system to which the embodiments of the present application are applicable.

FIG. 2 is a schematic diagram of a clock synchronization method.

FIG3 is a clock synchronization method provided in an embodiment of the present application.

FIG4 is a schematic structural diagram of a synchronization control message provided in an embodiment of the present application.

FIG5 is a schematic structural diagram of a subscription request message provided in an embodiment of the present application.

FIG6 is a schematic structural diagram of a policy delivery message provided in an embodiment of the present application.

FIG. 7 is a schematic structural diagram of a time information upload message provided in an embodiment of the present application.

FIG8 is a schematic structural diagram of a parameter publishing message provided in an embodiment of the present application.

FIG. 9 is a schematic diagram of a clock synchronization algorithm applicable to an embodiment of the present application.

FIG10 is a schematic diagram of a clock synchronization algorithm provided in an embodiment of the present application.

FIG. 11 is a schematic diagram of a clock synchronization algorithm provided in an embodiment of the present application.

FIG. 12 is a schematic diagram of a user interface provided in an embodiment of the present application.

FIG. 13 is a clock synchronization device provided in an embodiment of the present application.

FIG. 14 is another clock synchronization device provided in an embodiment of the present application.

DETAILED DESCRIPTION

The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings.

The terms used in the implementation section of this application are only used to explain the specific embodiments of this application and are not intended to limit this application.

In this application, the terms "first", "second", "third", etc. are used to distinguish the same or similar items with basically the same role and function. There is no logical or temporal dependency between "first", "second" and "third", and the quantity and execution order are not limited.

The present application will present various aspects, embodiments or features around a system that may include multiple devices, components, modules, etc. It should be understood and appreciated that each system may include additional devices, components, modules, etc., and/or may not include all of the devices, components, modules, etc. discussed in conjunction with the figures. In addition, combinations of these schemes may also be used.

In addition, in the embodiments of the present application, words such as "exemplary" and "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" in the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present concepts in a concrete way.

The network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. A person of ordinary skill in the art can appreciate that with the evolution of the network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

References to "one embodiment" or "some embodiments" etc. described in this specification mean that a particular feature, structure or characteristic described in conjunction with the embodiment is included in one or more embodiments of the present application. Thus, the phrases "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. appearing in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

In the present application, "at least one" means one or more, and "plurality" means two or more. "And/or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and/or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character "/" generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, c can be single or multiple.

Next, a system architecture applicable to an embodiment of the present application is introduced in conjunction with FIG. 1 .

As shown in FIG. 1 , FIG. 1 includes multiple nodes, and the multiple nodes may be connected via different communication media or be in different networks.

Exemplarily, FIG. 1 includes nodes 10, 11, 12, 13, 14, and 15, and nodes 10 to 15 may be in a local area network 1, for example, the local area network 1 may be a home network. Node 10 may be a control node and may be connected to all other nodes. Any node in FIG. 1 may be a different device, for example, node 10 (device 10) may be a whole-house smart host or a home storage center, etc., and the communication medium used for the connection may be different. Each node corresponds to one device, or may correspond to multiple devices. For example, the device of node 10 may be composed of multiple servers connected by wire or wireless. The following uses one node corresponding to one device as an example to illustrate the system architecture of the application of the embodiment of the present application. Node 10 may be a local device or may be located in the cloud. Node 11 (device 11) to node 15 (device 15) may be connected to device 10 using communication medium 1 to communication medium 5, respectively. Exemplarily, communication medium 1 to communication medium 5 may be Bluetooth, Ethernet, ZigBee technology, wireless fidelity technology (WiFi), etc.

Device 11 and device 12 may be in a local area network 2. For example, device 11 may be a router and device 12 may be a tablet computer. The two may communicate via a communication medium 6. Exemplarily, the communication medium 6 may be WiFi.

Device 13 and device 14 may be in a local area network 3, device 13 may be a smart light, device 14 may be a smart speaker, device 15 may be a mobile phone, and device 15 may communicate with device 14 via a communication medium 7. Exemplarily, communication medium 7 may be Bluetooth.

When collaborative communication or data fusion is required between two nodes, clock synchronization is required. The clocks of the nodes include system clocks, TSF clocks, etc. The TSF clock is the clock on the node network card, and the system clock is the clock used by the processor or CPU of the node. Since the upper-layer application or service can read the system clock more conveniently, the clock synchronization of the two nodes described in the embodiment of the present application mainly refers to the synchronization of the system clocks of the two nodes.

FIG2 shows a method for clock synchronization. As shown in FIG2, node 1 is device 1, node 2 is device 2, device 1 and device 2 are in a WiFi network, device 1 and device 2 have their own system clocks and TSF clocks, respectively, wherein the TSF clocks of the two devices have been synchronized according to the periodic beacon frame, after device 1 and device 2 establish a connection, the process of clock synchronization of the system clocks of the two devices may include the following steps:

S202, device 1 sends a local time measurement instruction to the WiFi driver at the application layer. S204, the WiFi driver of device 1 initiates a value acquisition request of a TSF (timing synchronization function, TSF) counter (also called TSF clock) to the network card firmware.

S206, the WiFi driver of device 1 receives a response from the network card firmware, obtains the value k1 of the TSF counter, and simultaneously obtains the value t1 of the local system clock.

In S206, the value of the TSF counter can be read in the network card firmware. The value of the TSF counter is the value of the TSF counter incremented at a uniform rate according to the local oscillator. The TSF counter is a 64-bit counter that increments once every microsecond. In the same WiFi system, the WiFi access point device periodically sends beacon frames to the devices (device 1 and device 2) connected to the WiFi. The beacon frame carries time information (the time information can be, for example, a timestamp or a value of a clock counter), so that device 1 and device 2 can complete the synchronization of the TSF clocks of device 1 and device 2 with the clock of the WiFi access point device according to the periodically received beacon frames and the estimated local delay.

The system clock is the clock used by the processor or CPU of device 1 and device 2. The system clock can be read by the layer above the device firmware, and the WiFi driver side can read the system clock.

S208, the WiFi driver of device 1 reports t1 and k1 to the application layer.

S210, device 1 sends a time difference measurement request message to device 2, and carries t1 and k1 in the time difference measurement request message.

S212, after receiving the time difference measurement request message, the application layer of device 2 sends a local time measurement instruction to the WiFi driver.

S214, the WiFi driver of device 2 initiates a TSF counter value acquisition request to the network card firmware.

S216, the WiFi driver of device 2 receives the response from the network card firmware, obtains the value k2 of the TSF counter, and simultaneously obtains the value t2 of the local system clock.

S218, the WiFi driver of device 2 reports t2 and k2 to the application layer.

S220, device 2 sends a time difference measurement response message to device 1 at the application layer, and carries t2 and k2 in the time difference measurement response message.

Since the TSF clocks of the two devices have been synchronized through periodic beacon frames, the clock offset value of the TSF clocks of the two devices can be considered to be 0. If the system clock of device 1 is synchronized with the system clock of device 2, the value of k2-k1 in Figure 2 should be equal to the value of t2-t1. Therefore, according to k1, k2 and t1, t2, device 1 and device 2 can respectively calculate the clock offset value _td = (t2-t1)-(k2-k1) of the system clocks between the two devices.

The clock synchronization method shown in FIG2 requires that the two devices for clock synchronization are in the same WiFi network and that the two devices have the ability of TSF synchronization. In other words, it needs to rely on the support of system hardware and communication protocols, which makes the synchronization method less versatile. For example, for the system shown in FIG1, if LAN 1 and LAN 3 are not WiFi networks, and LAN 2 is a WiFi network, only device 11 and device 12 are in the same WiFi network. Only devices equipped with WiFi network cards and using WiFi protocols can achieve TSF clock synchronization. Some devices may not have WiFi network cards. For example, the smart speaker represented by device 14 may not have a WiFi network card, and thus does not have the ability of TSF synchronization. The clock synchronization method shown in FIG2 cannot be applied to clock synchronization between any devices.

FIG3 shows a clock synchronization method provided by an embodiment of the present application, which can be applicable to a system including heterogeneous devices with different hardware configurations, communication capabilities and networking forms. The method includes:

S310, the first node sends a subscription request message to the control node, where the subscription request message is used to subscribe to a clock synchronization service between the first node and a second node, where the second node is a node that performs clock synchronization with the first node.

Correspondingly, the control node receives the subscription request message from the first node.

In the embodiment of the present application, the node corresponds to the device of each routing node in the heterogeneous network topology applied in the embodiment of the present application. For a node, the number of devices corresponding to the node may be more than one. For example, for a control node, it may include multiple devices, such as multiple servers or terminal devices combined through wired or wireless connections to form a node.

In addition, the embodiment of the present application does not limit the number of nodes that need to perform clock synchronization. For example, in addition to the second node, the target node that the first node needs to perform clock synchronization may also include other nodes, and the subscription request message will also include the identifier of the other node. For ease of explanation, the technical solution of the embodiment of the present application is described below using the example that the first node and the second node need to perform clock synchronization.

In order to realize the subscription and publication of clock synchronization services, each node needs to exchange relevant information, which can be sent through messages, such as subscription request messages and parameter publishing messages, policy delivery messages and time information upload messages mentioned later. The above messages can be collectively referred to as synchronization control messages. Synchronization control messages can be transmitted through link layer data frames of various communication media in the communication system.

FIG4 shows the structure of a synchronization control message provided by an embodiment of the present application. As shown in FIG4, the synchronization control message may include a link layer frame header, a payload field, and a check field. The link layer frame header carries control information related to the transmission control protocol, and the check field is used to detect the correctness and integrity of the message. The payload field carries a clock synchronization control message, which may be composed of a fixed header field, a variable header field, and a data field.

The fixed header field can exist in all types of synchronization control messages, indicating the type of control message in the synchronization control message and the flag bit corresponding to the type of control message. By defining different control message type field values in the payload fixed header field, it can be indicated whether the synchronization control message specifically belongs to a subscription request message, a policy delivery message, a time information upload message or a parameter release message. Corresponding to different synchronization control messages, the synchronization control message is used to indicate the related operations of clock synchronization and network nodes, such as the establishment and disconnection of network node connections, the subscription and unsubscription of clock synchronization services, the designation of clock synchronization strategies, the selection of time information aggregation nodes, the reporting of synchronization message time information, the release of clock synchronization parameters, heartbeat maintenance, etc. The control message flag bit includes a specific flag corresponding to each control message type field, such as a repeat transmission flag and a quality of service (QoS) level. The length field can identify the number of bytes remaining in the current clock synchronization control message, including the length of the variable header field and the data field.

The variable header field may include the synchronization control message and the protocol name, protocol version, connection flag, message identifier, etc. used by the node that sends or receives the synchronization control message.

The specific content included in the data field is related to the specific type of the synchronization control message. Specifically, it will change with whether the synchronization control message is a subscription request message, a policy delivery message, a time information upload message or a parameter release message, which will be described in detail later.

The control node may be a remote device, such as a cloud server, or a local device, such as a whole-house smart host or a home storage center. The first node and the second node may be other nodes except node 10 in FIG. 1 , which are nodes that require clock synchronization, and may be various terminal devices connected by different communication media in the heterogeneous network shown in FIG. 1 , for example, the first node may be a smart phone 15, and the second node may be a smart speaker 14; or the first node may be a router 11, and the second node may be a tablet 12, etc.

The first node and the second node can perform clock synchronization according to actual application needs. For example, the devices on node 1 and node 2 both have application 1 that needs to perform clock synchronization. Schematically, application 1 can be a communication application. Node 1 and node 2 need to communicate through application 1. Then the subscription request message can be sent by one of nodes 1 and 2. For example, the subscription request message can be sent by a sending node or a node that initiates communication between node 1 and node 2. In this case, the first node is node 1 and the second node is node 2. The subscription request message can also be sent by both node 1 and node 2. In this case, for subscription request message 1 sent by node 1, the first node is node 1 and the second node is node 2; for subscription request message 2 sent by node 2, the first node is node 2 and the second node is node 1.

It should be understood that the present application does not limit a node to only send one subscription request message. For example, for the above-mentioned application 1, when node 1 is a sending node, node 1 can send subscription request message 1; at the same time, there is application 2 that requires clock synchronization on the devices of node 1 and node 3. When node 1 and node 3 interact using application 2, node 1 is also the initiating node of the interaction performed by application 2, then node 1 can also send subscription request message 3. The following takes the example of node 1 sending subscription request message 1 in application 1 as an example to describe the details of the embodiment of the present application in detail.

In S310, the subscription request message may include the identifier of the first node (local node identifier), the identifier of the second node (target node identifier) and the clock synchronization accuracy. Optionally, the subscription request message may also include any one or more of the communication medium supported by the first node, the clock synchronization period, the clock synchronization convergence speed, the time information marking method, and the synchronization message processing priority.

FIG5 shows the structure of a subscription request message provided in an embodiment of the present application. The details of the fixed header field and the variable header field in the subscription request message can refer to FIG4 and the relevant introduction of the corresponding synchronization control message. In the data field, the local node identification field carries the identification of the first node, the target node identification field carries the identification of the second node, and the clock synchronization accuracy field carries the clock synchronization accuracy requirements of the first node and the second node. The data field may also include a communication medium type field, which carries the type of communication medium supported by the first node, and may also include an option field as an extension field to illustrate the first node's requirements for clock synchronization service performance and synchronization process execution. For example, the option field may carry one or more of the expected clock synchronization period, clock synchronization convergence speed, time information marking method, synchronization message processing priority, etc.

The identifier of the first node is the identifier of the node that sends the subscription request message. For example, it can be the client identifier, user identifier, physical address (for example, it can be a media access control (MAC) address), serial number (SN), international mobile equipment identity (IMEI), international mobile subscriber identification (IMSI), attribute hash value, etc. of the node, which are used to uniquely identify the first node.

The identifier of the second node is the target node identifier for clock synchronization with the first node. Specifically, it can be a unique identifier such as the client identifier, user identifier, physical address (for example, a media access control (MAC) address), serial number (SN), international mobile equipment identity (IMEI), international mobile subscriber identification (IMSI), attribute hash value, etc. of the second node.

The node identifier can distinguish device nodes with different characteristics in the network. For example, it can distinguish whether the node supports multiple communication media, whether the node is logged in to the same account, whether the node belongs to a trusted device group, etc. Through the identifier of the first node, the control node can determine whether to formulate a corresponding clock synchronization strategy for the first node. For example, if the control node determines that the first node does not belong to a trusted device group through the identifier of the first node, the control node may not formulate a corresponding clock synchronization strategy for the first node or give priority to meeting the clock synchronization requirements of the nodes or devices in the trusted device group.

The clock synchronization accuracy can have different levels, which can be seconds, milliseconds or microseconds, etc., which is related to the specific business type and required service quality of the first node and the second node. For example, for communication services for the purpose of video playback and file sharing, the required clock synchronization accuracy is different.

The communication medium type supported by the first node is used to indicate the communication medium and connection method that the first node can use, such as Ethernet, wireless fidelity (WiFi), Bluetooth, ZigBee technology, power line carrier (PLC), etc.

The clock synchronization period may have different values according to different service types, network conditions, and synchronization accuracy requirements, and is used to characterize the transmission period of the synchronization message and the clock adjustment period of the first node during the execution of the synchronization process.

The clock synchronization convergence speed may indicate the speed at which the clock synchronization operation is completed or the time required to achieve stable clock synchronization.

The time information marking method refers to the method in which the first node marks the sending time and receiving time of the synchronization message, such as reading the system time (software clock) in the user space and reading the network card time (hardware clock) in the kernel space.

The synchronization message processing priority indicates the processing priority of the synchronization message routing node for the synchronization message, such as the priority of message encoding and sending and the priority of message receiving and decoding. During the clock synchronization process, various synchronization control messages sent and received by the first node may need to be forwarded by a third-party routing node. By marking the synchronization message processing priority in the subscription request message, the control node and the routing node can determine the priority of the clock synchronization service of the first node, and coordinate the processing order of multiple clock synchronization services including the clock synchronization service of the first node accordingly.

S320: The control node determines a policy delivery message according to the subscription request message, where the policy delivery message includes a clock synchronization algorithm.

S330, the first node obtains a clock synchronization parameter, where the clock synchronization parameter is used for a clock synchronization service and is determined according to a clock synchronization algorithm.

In S320, the control node determines the policy delivery message according to the subscription request message. Specifically, the control node can determine the content of the policy delivery message, such as the clock synchronization algorithm, by referring to the clock synchronization accuracy of the first node and the second node, the communication medium type of the first node and the communication medium type of the second node.

When the subscription request message does not include the communication medium type supported by the first node, the control node can determine the communication medium type supported by the first node according to the identifier of the first node and determine the communication medium type supported by the second node according to the identifier of the second node. When only the first node sends a subscription request message carrying the communication medium type supported by the first node, the second node can send the communication medium type supported by the second node to the control node through other information or the control node can determine the communication medium type supported by the second node according to the identifier of the second node in the subscription request message. In this way, the control node can obtain the communication medium type and clock synchronization accuracy supported by the two nodes, and determine the strategy to send the message accordingly.

When the subscription request message also includes information such as clock synchronization period, clock synchronization convergence speed, time information marking method, synchronization message processing priority, etc., the control node can also refer to this information to determine the content of the policy delivery message, such as the clock synchronization algorithm.

In addition, when the control node determines the policy sending message, it will also refer to at least one of the load of the network nodes (first node and second node), the usage of network resources and the communication status, and the policy sending message determined by the control node can be sent to the corresponding node.

In S330, the first node obtains clock synchronization parameters, which are determined according to the clock synchronization algorithm determined by the control node. The clock synchronization parameters may include any one of the following: the clock offset value between the first node and the second node, the clock frequency deviation between the first node and the second node, the difference between the clock value of the first node and the first reference clock value, the difference between the clock frequency of the first node and the first reference clock frequency, the target clock value of the first node, the target clock frequency of the first node, etc.

For example, the first node may align the clock of the first node with the clock of the second node based on the clock offset value or frequency offset value of the first node and the second node (or the second node may align the clock of the second node with the first node based on the clock offset value or clock rate offset value of the first node and the second node).

For another example, the first node may adjust the clock of the first node to the first reference clock value and the first reference clock frequency based on the difference between the clock value of the first node and the first reference clock value and the difference between the clock frequency of the first node and the first reference clock frequency (the second node may also adjust the clock of the second node to the first reference clock value and the first reference clock frequency based on the difference between the clock value of the second node and the first reference clock value and the difference between the clock frequency of the second node and the first reference clock frequency), so that the clock of the first node and the clock of the second node can be aligned.

For example, the first node can adjust the clock of the first node to the target clock value or target clock frequency based on the target clock value or target clock frequency (the second node can adjust the clock of the second node to the target clock value or target clock frequency based on the target clock value or target clock frequency), so that the clocks of the first node and the second node are aligned.

It should be understood that when the nodes that need clock synchronization also include other nodes, such as a third node, that is, when the first node, the second node, and the third node need clock synchronization, the clock values of the two nodes can be aligned to another node, for example, the clocks of the first node and the third node are aligned to the second node, so that the clock synchronization parameter for the first node is the clock offset value and/or clock frequency deviation of the first node and the second node, and the clock synchronization parameter for the third node is the clock offset value and/or clock frequency deviation of the third node and the second node. All nodes can also be aligned to a reference clock value and a reference clock frequency, and the present application does not limit the specific form of the clock synchronization parameter. In addition, when a node needs to adjust the local clock value or clock frequency during the clock synchronization process, the node can obtain the corresponding clock synchronization parameter. The embodiment of the present application takes the first node needing to adjust the local clock as an example to introduce the technical solution provided in the embodiment of the present application, and does not mean a restriction on the node that adjusts the local clock. For example, when the first node does not need to adjust the local clock, S330 can be, the second node obtains the clock synchronization parameter. In addition, when the first node does not need to adjust the local clock, it can also obtain the clock synchronization parameters. That is, all nodes that need to perform clock synchronization can obtain the clock synchronization parameters, but only the nodes that need to adjust the local clock adjust the local clock according to the clock synchronization parameters.

In an embodiment of the present application, the policy delivery message may further include an identifier of the execution node, and the control node may send the policy delivery message to the execution node; the execution node executes the clock synchronization algorithm according to the policy delivery message, and the clock synchronization parameters are determined according to the time information of the synchronization message sent and/or received by the execution node when executing the clock synchronization algorithm, and the time information includes the value or timestamp of the clock counter associated with the execution node sending the synchronization message and/or the value or timestamp of the clock counter associated with the execution node receiving the synchronization message.

That is to say, the control node will determine the clock synchronization algorithm and the node (execution node) that executes the clock synchronization algorithm, and the control node will send the policy message to the execution node, so that the execution node can execute the corresponding clock synchronization algorithm. Since the clock synchronization algorithm for the clock synchronization service of the first node and the second node is formulated by the control node, the control node can determine the appropriate clock synchronization algorithm based on one or more of the information such as the hardware configuration of the first node and/or the second node, the type of communication medium supported, the networking form of the network, the network resource usage and the clock synchronization accuracy, and determine the execution node that executes the clock synchronization algorithm. Finally, the execution node or the control node can calculate the clock synchronization parameters for the clock synchronization service of the first node and the second node based on the data information (time information) collected during the execution of the clock synchronization algorithm.

In an embodiment of the present application, the execution node may include a first node and a second node, or the execution node may not include the first node and/or the second node. The following first takes the execution node including the first node and the second node as an example to introduce the specific scheme of the embodiment of the present application.

In the case where the execution node calculates the clock synchronization parameters according to the time information during the execution of the clock synchronization algorithm, if the execution node includes a first node and a second node, the clock synchronization parameters can be directly calculated by the first node or the second node, and it can be pre-specified that, for example, the first node that sends the subscription request message calculates the clock synchronization parameters and updates the local clock, and the first node can directly obtain the clock synchronization parameters. The first node and the second node can also calculate the clock synchronization parameters separately and align their respective local clocks to the reference clock value and/or reference clock frequency.

When the execution node uploads the time information to the control node, the control node determines the clock synchronization parameters, and the clock synchronization parameters can be carried in the parameter publishing message and sent to the first node. For different nodes and clock synchronization services for different purposes or applications in the heterogeneous network system, the control node can formulate different clock synchronization strategies to reduce the overall system overhead while meeting the requirements of the clock synchronization services of the first node and the second node.

The timestamp and the clock counter values mentioned in the embodiments of the present application correspond to the time of the node when the execution node sends or receives the synchronization message. It can be the timestamp or the clock counter value read or marked before sending or receiving the message, or it can be the timestamp or the clock counter value read or marked when sending or receiving the message or after sending or receiving the synchronization message. The local clock can be a physical clock, a logical clock, etc. such as a system clock or a TSF clock, and these clocks display the time in the form of a timestamp or a clock counter value (for example, the clock counter value can be read by the TSF clock mentioned later, the timestamp can be read by the system clock mentioned later, and the clock counter value and the timestamp can also be read by other clocks, which will not be repeated here). In some embodiments, the clock synchronization parameter can be determined by the timestamp marked when receiving the synchronization message or the value of the clock counter read, and the synchronization message can be one or more messages exchanged between the execution nodes. In other embodiments, the clock synchronization parameter can be determined by the timestamp marked when sending the synchronization message (or before sending the synchronization message) and the timestamp marked when receiving the synchronization message or the value of the clock counter read.

In some embodiments of the present application, the policy delivery message may also include the identifier of the aggregation node. The aggregation node is not the first node. Before the first node obtains the clock synchronization parameters, the control node will also send the policy delivery message to the aggregation node (including the synchronization message interaction form, time information processing method, etc.), and the execution node can send a time information upload message to the aggregation node, and the time information upload message includes time information; thus, the aggregation node determines the clock synchronization parameters according to the time information and the clock synchronization algorithm, and carries the clock synchronization parameters in the parameter release message and sends it to the first node. In other words, the control node will determine the aggregation node, and the aggregation node will determine the clock synchronization parameters according to the time information and the clock synchronization algorithm in the process of the execution node executing the clock synchronization algorithm, and then the aggregation node will send the clock synchronization parameters to the first node through the parameter release message.

For example, the aggregation node may be the second node. When the execution node includes the first node and the second node, when the first node and the second node execute the clock synchronization algorithm, the first node may carry the timestamp or the value of the clock counter (time information) associated with the sending and/or receiving synchronization message in the time information upload message and send it to the second node, so that the second node as the aggregation node can calculate the clock synchronization parameters and send the clock synchronization parameters to the first node.

For another example, the aggregation node may not be the first node and the second node. When the first node and the second node execute the clock synchronization algorithm, the first node and the second node may carry the timestamp or the value of the clock counter (time information) associated with sending and/or receiving the synchronization message in the time information upload message and send it to the aggregation node, and the aggregation node calculates the clock synchronization parameter and sends it to the first node and/or the second node.

Optionally, in addition to the aggregation node directly sending the clock synchronization parameters to the first node, in some scenarios, for example, when the length of the routing path from the aggregation node to the first node is greater than the length of the routing path from the control node to the first node, the aggregation node can send the clock synchronization parameters to the control node, and the control node carries the clock synchronization parameters in a parameter publishing message and sends it to the first node.

That is to say, the parameter release message can be received by the first node from the control node. Before the first node obtains the clock synchronization parameters, the control node will send a message through a policy to inform the aggregation node of the clock synchronization algorithm currently used (including the synchronization message interaction form, time information processing method, etc.). The execution node can send a time information upload message to the aggregation node, and the time information upload message includes time information; thereby, the aggregation node determines the clock synchronization parameters based on the time information and the clock synchronization algorithm and sends them to the control node; the control node sends a parameter release message carrying the clock synchronization parameters to the first node.

In other embodiments of the present application, the policy message also includes the identifier of the aggregation node, the aggregation node is the first node, and the first node obtains the clock synchronization parameters including: the execution node sends a time information upload message to the aggregation node, the time information upload message includes time information; the aggregation node determines the clock synchronization parameters based on the time information.

That is to say, the aggregation node is the first node. When the first node and the second node execute the clock synchronization algorithm, the second node can carry the timestamp or clock counter value associated with the sending and/or receiving synchronization message in the time information upload message and send it to the first node. After the first node calculates the clock synchronization parameters based on the time information, it can directly adjust the local clock according to the clock synchronization parameters. The first node can also send the clock synchronization parameters to the second node, and the second node can also adjust the local clock accordingly according to the clock synchronization parameters.

The policy delivery message sent by the control node includes a clock synchronization algorithm and may also include at least one of an identifier of an execution node and an identifier of a convergence node. In some embodiments, the policy delivery message may also include at least one of a first clock synchronization period, a type of synchronization message, a communication medium used for transmission of the synchronization message, and a time information marking method of the synchronization message. The first clock synchronization period is a period during which the execution node executes the clock synchronization algorithm.

FIG6 shows the structure of a policy-sent message provided by an embodiment of the present application. As shown in FIG6 , the details of the fixed header field and the variable header field of the message can refer to the introduction of FIG4 . The data field may include: a clock synchronization policy flag field. Optionally, the data field of the policy-sent message may also include: at least one of the fields for indicating the execution node identifier, the aggregation node identifier, the synchronization message type, the first clock synchronization cycle, the synchronization message communication medium, and the synchronization message time information marking method. If the policy-sent message only includes the clock synchronization policy flag field, the first node and the second node that subscribe to the clock synchronization service can be defaulted to execute the clock synchronization algorithm and calculate the clock synchronization parameters to complete the clock synchronization service. When the control node determines the execution node that executes the clock synchronization algorithm and the aggregation node that performs the clock synchronization parameter calculation based on the hardware configuration, load, network resource usage and communication status of the first node and/or the second node, the corresponding fields can be set in the policy-sent message.

Among them, the clock synchronization policy flag field represents the clock synchronization algorithm specified by the control node for the nodes (first node and/or second node) subscribing to the clock synchronization service, the execution node identification field and the aggregation node identification field carry the identification of the execution node and the aggregation node respectively, the synchronization message type field carries the synchronization message type, and the clock synchronization cycle field carries the first clock synchronization cycle.

The clock synchronization algorithms may include: network time protocol (NTP), precision time protocol (PTP), flooding time synchronization protocol (FTSP), gradient time synchronization protocol (GTSP), probabilistic clock synchronization protocol, WiFi TSF-based clock synchronization protocol, and weighted average-based clock synchronization protocol.

The execution node is the node that executes the synchronization strategy. The execution node may include the subscription node of the clock synchronization service (the node indicated by the local node and the target node in the subscription request message), and may also include nodes other than the subscription node of the clock synchronization service. The identifier of the execution node is the identifier of the node that executes the clock synchronization algorithm.

The synchronization message type indicates the message type that the execution node exchanges when executing the clock synchronization algorithm. By specifying the synchronization message type, the execution node can use the corresponding protocol flow and processing mechanism to exchange synchronization messages and mark timestamps (clock counter values). For example, the synchronization message type can be a user datagram protocol (UDP) message, a transmission control protocol (TCP) message, a link layer data frame, a beacon frame, and a heartbeat message. The control node can determine the type of synchronization message based on factors such as the communication medium type supported by the execution node, the node load, the communication quality, and the selected clock synchronization algorithm. For example, the UDP message has a small overhead, and the type of synchronization message can be determined as a UDP message when the execution node load is large or the synchronization accuracy requirement is high; the WiFi network supports TCP and UDP messages. When the execution nodes send and receive messages through WiFi, TCP or UDP messages can be selected; and when the execution nodes send and receive messages through Bluetooth, the message type is a link layer data frame.

The clock synchronization period indicates the average time interval for executing the clock synchronization process of the node. The clock synchronization period may be consistent with or inconsistent with the clock synchronization period carried in the option field of the node (first node) subscribing to the clock synchronization service in the subscription request message. The clock synchronization period may be determined by the control node based on the length of the confidence interval of the historical clock value of the first node or the second node and the clock synchronization accuracy. The control node may also determine the clock synchronization period based on factors such as the communication status and the resources of the node.

The aggregation node is the node to which the execution node reports and aggregates time information when executing the clock synchronization strategy. That is to say, during the execution of the clock synchronization algorithm and the interaction of synchronization messages, the execution node will send time information (at least one of the marked message sending time information, the marked message receiving time information, and the clock counter value associated with the sending or receiving of the synchronization message) to the aggregation node, so that the aggregation node can calculate the synchronization parameters.

For example, the aggregation node may have strong computing and storage capabilities, and may calculate clock synchronization parameters between execution nodes (eg, clock offset values and/or frequency offset values of execution nodes) based on time information reported by the execution nodes, and issue corresponding clock synchronization parameters.

After the control node sends the policy delivery message to the execution node and the aggregation node, the execution node can execute the clock synchronization algorithm according to the policy delivery message and upload the time information to the aggregation node through the time information upload message.

The time information may include the time information type and the corresponding time information data, and also include the identifier of the sending node and the identifier of the receiving node of the synchronization message corresponding to the time information.

FIG7 shows the structure of a time information upload message provided by an embodiment of the present application. The details of the fixed header field and the variable header field of the time information upload message can refer to the specific description of FIG4 , and the data field may include: a local node identification field, a peer node identification field, and multiple time information structure fields. Specifically, the local node identification field and the peer node identification field may carry the identification of the sending node and the receiving node of the message corresponding to the time information, and multiple time information structure fields may carry different time information. Each time information structure may include a time information type and time information data.

The sending node and the receiving node are the sending node and the receiving node of the synchronization message corresponding to the time information. Therefore, a time information upload message only includes the time information (timestamp or clock counter value) of the synchronization message exchanged between the two nodes. For example, when executing the clock synchronization algorithm, if it is necessary for nodes 1 and 2 to interact with each other through synchronization messages, and it is necessary for nodes 1 and 3 to interact with each other through synchronization messages. Then, node 1 and/or node 2 may send time information upload message 1 to upload the time information of the synchronization message interaction between node 1 and node 2, and node 1 and/or node 3 may send time information upload message 2 to upload the time information of the synchronization message interaction between node 1 and node 3. Different clock synchronization algorithms require different time information to be uploaded. For example, for a clock synchronization algorithm that uses two-way message interaction, both the sending time and receiving time of the synchronization message need to be carried in the time information upload message and uploaded to the aggregation node (that is, the clock counter value or marked timestamp read when sending the synchronization message and the clock counter value or marked timestamp read when receiving the synchronization message can be uploaded, that is, the clock counter value or timestamp associated with the sending and receiving of the synchronization message). For a clock synchronization algorithm that uses one-way message transmission, only the receiving timestamp of the synchronization message or the clock counter value read when receiving the synchronization message (the clock counter value or timestamp associated with the reception of the synchronization message) can be uploaded.

Each time information structure in the time information upload message may include a time information type and time information data. The time information type is related to the clock synchronization algorithm used by the execution node during synchronization. For example, for the WiFi TSF-based clock synchronization protocol (Figure 2), it may include a timestamp and a clock counter value associated with the sending and receiving of synchronization messages), and the time information data is the specific value of the corresponding time information type.

In the above embodiment, since the time information of the execution node during the execution of the clock synchronization algorithm will be sent to the aggregation node through the time information upload message, when the aggregation node determines the clock synchronization parameters based on the time information, it will send the clock synchronization parameters to the first node and/or the second node that needs the clock synchronization service through the parameter publishing message.

It should be understood that in the embodiment of the present application, when the first node and the second node perform clock synchronization, the first node subscribes to the clock synchronization service, and the node that needs to adjust the local clock (physical clock such as system clock or TSF clock, logical clock) can be one of the first node or the second node, or the first node and the second node. The aggregation node will calculate the corresponding clock synchronization parameters according to the distribution of nodes that need to adjust the local clock (such as some nodes that need clock synchronization services and all nodes that need clock synchronization services).

Still taking the need for clock synchronization between the first node and the second node as an example, for ease of application, the node that subscribes to the clock synchronization service (the node that sends the subscription request message, the first node) can adjust the local clock by default, or it can be determined by the control node when formulating the clock synchronization strategy or the aggregation node when calculating the clock synchronization parameters. This application does not limit this. The aggregation node can carry the clock synchronization parameters in a parameter release message and send it to the node that needs to adjust the clock, or it can send the parameter release message to all nodes that need clock synchronization, regardless of whether the node needs to adjust the clock. The following takes the example of the first node receiving a parameter release message including clock synchronization parameters to introduce the specific details of the parameter release message.

Figure 8 shows the structure of a parameter publishing message provided by an embodiment of the present application. As shown in Figure 8, the details of the fixed header field and the variable header field of the message can refer to the relevant description of Figure 4, the data field can include a node identifier and a clock synchronization parameter, the node identifier field carries the node that needs to adjust the local clock, and the clock synchronization parameter field can carry a clock offset value and/or a clock frequency deviation and/or a clock value for executing node updates, etc.

Clock synchronization parameters may include parameters such as the clock offset value (clockoffset) and clock frequency deviation (clockskew) between different nodes that require clock synchronization services. The parameter release message may also include a node identifier, which corresponds to the node that needs to adjust the clock. For example, in the scenario where the first node and the second node are synchronized, it may be the identifier of the first node and/or the identifier of the second node.

In an embodiment of the present application, after the control node sends the policy release message, it can also update the clock synchronization period, the clock synchronization algorithm and the content carried in other policy release messages.

Specifically, for the clock synchronization cycle, the control node can determine the second clock synchronization cycle based on the length of the confidence interval of the clock value of the first node and the clock synchronization accuracy, or the control node can determine the second clock synchronization cycle based on the length of the confidence interval of the clock value of the second node and the clock synchronization accuracy, the confidence interval of the clock value of the first node or the confidence interval of the clock value of the second node is determined by the aggregation node according to the clock synchronization parameters; the aggregation node sends the confidence interval of the clock value to the control node, and then the control node sends the second clock synchronization cycle to the execution node; the execution node executes the clock synchronization algorithm according to the second clock synchronization cycle; wherein, when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the first clock synchronization cycle is the second clock synchronization cycle; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than the first preset threshold and the length of the confidence interval is greater than the clock synchronization accuracy, the second clock synchronization cycle is less than the first clock synchronization cycle; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than the first preset threshold and the length of the confidence interval is less than the clock synchronization accuracy, the second synchronization cycle is greater than the first clock synchronization cycle.

That is, the control node may adjust the clock synchronization period of the first node and the second node according to the estimation of the confidence interval of the clock values of the first node and the second node and the clock synchronization accuracy requirement.

For example, for a first node and a second node that need to perform clock synchronization, after receiving the time information, the sink node can calculate the clock synchronization parameters (clock offset value) of the first node and the second node using a statistical learning method. and clock frequency deviation The sink node may determine the predicted clock value of the first node based on the collected clock value (T ₂ ) of the second node.

In addition, the aggregation node can estimate the confidence interval of the clock value prediction of the first node based on the actual clock value collected on the first node side and probability statistics theory, and the confidence interval can be sent to the control node. The control node can update the clock synchronization period of the first node and the second node to the second synchronization period by comparing the length of the confidence interval of the clock value prediction and the size of the clock synchronization accuracy carried by the subscription request message.

When the absolute value of the difference between the length of the confidence interval of the first node and the clock synchronization accuracy is greater than a preset threshold, the clock synchronization period of the first node and the second node can be adjusted. Specifically, when the sum of the length of the confidence interval and the preset threshold is less than the clock synchronization accuracy, the clock synchronization period of the first node and the second node can be increased, for example, the clock synchronization period is adjusted to twice the original. When the sum of the length of the confidence interval of the clock prediction value of the first node and the preset threshold is greater than the clock synchronization accuracy, the clock synchronization interval between the second node and the first node can be reduced, for example, the clock synchronization period is adjusted to half of the original. When the absolute value of the difference between the length of the confidence interval of the first node and the clock synchronization accuracy is less than the preset threshold, the clock synchronization period of the first node and the second node may not be adjusted.

The preset threshold may be related to factors such as business applications that rely on clock synchronization, node load, and network resource usage, and may be set to a multiple of the clock synchronization accuracy (eg, 1.2 times, 2 times, etc.).

After determining the second clock synchronization cycle, the control node may send the second clock synchronization cycle to the execution node and the control node, so that the execution node exchanges synchronization messages according to the second clock synchronization cycle to perform clock synchronization operations.

It should be understood that when the control node determines the first clock synchronization period for clock synchronization of the first node and the second node, it can determine the first clock synchronization period based on the length of the confidence interval of the historical clock value of the first node or the second node and the clock synchronization accuracy. The control node will also determine the first clock synchronization period based on factors such as communication conditions and node resources.

Furthermore, after determining the second clock synchronization period, the control node can update the clock synchronization algorithm used by the execution node based on the network resource usage and the network node load, thereby reducing the overall clock synchronization overhead while meeting the clock synchronization accuracy requirements. For example, the clock synchronization algorithm is adjusted from a method based on WiFi TSF synchronization to a method based on two-way interaction of synchronization messages to avoid dependence on the underlying chip hardware and reduce the processor load. For another example, the clock synchronization algorithm is adjusted from a method based on WiFi transmission of synchronization messages to a method based on Bluetooth transmission of synchronization messages to reduce the power consumption of clock synchronization.

In addition, the control node may also update the communication medium used for synchronization message transmission, the time information marking method of the synchronization message, the type of the synchronization message, etc.

In some embodiments, the aggregation node can also determine the second clock synchronization cycle in a manner similar to the control node, and determine the second clock synchronization algorithm based on the second clock synchronization cycle, and then send a new policy message to the execution node. The policy message includes the second synchronization cycle and the second clock synchronization algorithm, so that the execution node can execute the second clock synchronization algorithm according to the policy message.

For the clock synchronization algorithm determined by the control node (corresponding to the clock synchronization policy flag field in the policy delivery message), the control node determines the clock synchronization algorithm based on the clock synchronization requirements of the first node and the second node (clock synchronization accuracy), network resource usage, network connection status, and node time reading method. The clock synchronization algorithm specifically used in the embodiments of the present application in different situations is introduced below using Figures 9 to 11 as examples.

For nodes that can only mark message time information in user mode (or non-NIC driver firmware side), when millisecond-level clock synchronization accuracy is required, a synchronization method based on two-way message interaction can be used. Taking the first node and the second node requiring clock synchronization as an example, Figure 9 gives an example of the clock synchronization algorithm, including:

S910: The first node sends a synchronization request message to the second node.

The first node will record the time T _0, when the synchronization request message is sent at the upper layer of the protocol stack (such as the application layer), and carry the time T _0, in the synchronization request message.

S920: The first node receives a synchronization response message returned by the second node.

The synchronization response message includes the time _T1 when the second node receives the synchronization request message and the time _{T2 when the synchronization response message is sent.} When the first node receives the synchronization response message, it will record the time T3 when the synchronization response message is received in the upper layer of the protocol stack _.

In FIG9 , T _0, and T _3, are the system time of the first node, and T _1, and T _2, are the system time of the second node. The clock offset between the first node and the second node is defined as θ _offset , and the one-way message communication delay between the first node and the second node is defined as d . When the clock drift between the first node and the second node is ignored (the clock frequency deviation is 0), based on the recorded time information T _0, , T _1, , T _2, and T _3, , the clock offset θ _offset between the first node and the second node and the one-way message communication delay d can be associated by the following equation (2):

T _1,1 =T _0,1 +θ _offset +d

T _3,1 =T _2,1 -θ _offset +d(2)

By solving the above equation (2), the clock offset value θ _offset between the first node and the second node and the value of the one-way message communication delay d can be calculated, as shown in formula (3):

When the clock synchronization strategy formulated by the control node uses the synchronization method shown in FIG9 , the clock synchronization strategy flag in the strategy delivery message may indicate the synchronization method using two-way message interaction, the execution node identifier may include the local node identifier and the target node identifier in the subscription request message sent by the first node, and the synchronization message type may be: UDP message, TCP message, link layer data frame, etc. The clock synchronization period may be determined based on the clock synchronization period carried in the subscription request message of the first node, the network resource usage, and the communication status, etc., or may be specified by a system preset value, and the aggregation node identifier may be the identifier of the first node or the second node, or the identifier of another node.

Taking the aggregation node as other nodes as an example, the first node can report the time information to the aggregation node. The time information upload message can include 4 time information structures, and the "time information type-time information data" are: synchronization request message sending time-T ₀ , synchronization request message receiving time-T _1, synchronization response message sending time-T _2, and synchronization response message receiving time-T ₃ .

After receiving the time information upload message, the aggregation node can calculate the clock offset value of the first node relative to the second node, and carry the clock offset value and the first node identifier in the parameter publishing message to the first node and the control node, so that the first node can adjust the local system clock according to the clock offset value of the message to achieve clock synchronization with the second node.

When nodes that require clock synchronization services require higher clock synchronization accuracy, clock synchronization algorithms based on two-way message interaction will be difficult to meet the requirements due to the uncertainty of message time information marking (timestamp marking or clock counter value reading) and the asymmetry of message interaction delay. To this end, the method of passively monitoring public nodes (such as routing nodes and network access points) unidirectional broadcast reference messages can be used to replace two-way message interaction, thereby avoiding the asymmetry of message interaction delay and reducing the uncertainty of message time information marking.

In the clock synchronization algorithm, taking the need for clock synchronization between a first node and a second node as an example, the execution nodes include the first node, the second node and the third node, and the third node is used as a reference message sending node. The time information reported to the convergence node includes: the time when the first node receives multiple reference messages and the time when the second node receives multiple reference messages; the clock synchronization parameter determined by the convergence node includes at least one of the following: the difference between the clock value of the first node and the clock value of the second node and the difference between the clock frequency of the first node and the clock frequency of the second node; or, the clock synchronization parameter includes at least one of the following: the difference between the clock value of the first node and the first reference clock value, the difference between the clock value of the second node and the first reference clock value, the difference between the clock frequency of the first node and the first reference clock frequency, and the difference between the clock frequency of the second node and the first reference clock frequency; wherein, the execution node executes the clock synchronization algorithm including: the third node sends multiple reference messages to the first node and the second node.

The reference message may be sent periodically. In some embodiments, the sending period of the reference message is consistent with the clock synchronization period between the first node and the second node. In another embodiment, the third node sends the multiple periodic reference messages in each clock synchronization period.

Specifically, Figure 10 shows a specific embodiment of the clock synchronization method based on unidirectional broadcast messages provided in an embodiment of the present application, as shown in Figure 10 (a) and Figure 10 (b), for example, L node and N node need to perform clock synchronization, the control node is A node, the aggregation node is D node, and the execution nodes are L node, N node, and K node, wherein K node is not a node that requires clock synchronization service, and K node is a reference message broadcast node selected by A node (control node).

When executing the clock synchronization algorithm, the K node can send R reference messages to the L node and the N node in the form of broadcasting, so that after receiving the broadcast reference message, the two nodes can record the reception time of multiple reference messages in the kernel state (such as the network card firmware) or user state according to the clock synchronization algorithm and the local time reading capability, and upload the reception time to the aggregation node D.

The time T _2,i when the L node receives the i-th synchronization message and the time T _3,i when the N node receives the i-th synchronization message satisfy the relationship shown in formula (4):

in, is the uncertainty part of the delay of node K sending the i-th synchronization message to node L, is the uncertainty part of the delay of K node sending the i-th synchronization message to N node, θ _skew and θ _offset are the clock frequency deviation and clock offset values between L node and N node respectively, d ^KL and d ^KN are the deterministic part of the one-way transmission delay of K node sending synchronization message to L node and N node respectively, the "time information type-time information data" included in the time information upload message of L node is "i-th message reception time-T _2,i ", the "time information type-time information data" included in the time information upload message of N node is "i-th message reception time-T _3,i ", and the time information type-time information data included in the time information upload message of K node is "i-th message sending time-T _1,i ". Clock frequency deviation and clock offset values between K node and L node and Clock frequency deviation and clock offset value of K node and N node and The relationship satisfying formula (5) is:

When the uncertainty of the delay between KL and KN is and When the normal distribution is satisfied and the node drift (clock frequency deviation) between the L node and the N node is ignored, θ _skew = 0, then the clock offset value θ _offset of the L node and the N node can be calculated by formula (6):

When the uncertainty of the delay between KL and KN is and When the normal distribution is satisfied and the node drift between the L node and the N node is considered (the clock frequency deviation is not 0), the clock offset value θ _offset and the clock frequency deviation θ _skew of the L node and the N node can be calculated by formula (7):

x[i]＝T _2,i -T _3,i -μ

μ＝d ^KL -d ^KN

D _i = T _1,i -T _1,1 (7)

After calculating the clock offset value and/or clock frequency deviation, the aggregation node D can carry the clock offset value and/or clock frequency deviation in the clock synchronization parameter release message and send it to the L node or N node respectively. Optionally, the aggregation node D can also first send the synchronization parameter to the control node A node, and then the A node sends it to the L node or N node. It should be understood that the above formula (6) and formula (7) align the L node to the N node or the N node to the L node. In some embodiments, the L node and the N node can also be adjusted to the same reference clock value and/or reference clock frequency. The present application does not limit the specific clock adjustment method.

For network synchronization nodes that support WiFi communication and TSF counter reading, the TSF counter can be used to synchronize the system clock. For example, for a scenario where the nodes to be synchronized are in the same local area network, the synchronization method shown in Figure 2 can be used for clock synchronization.

For the scenario where the nodes that need to be synchronized are not in the same local area network, an embodiment of the present application provides a clock synchronization method. The first node and the second node can first perform clock synchronization in sequence. When the nodes that need to perform clock synchronization with the first node also include other nodes, after the first node and the second node perform clock synchronization, other nodes can be used to perform clock synchronization with the first node in a similar manner to the second node, and finally all nodes that require clock synchronization services achieve clock synchronization. The following first introduces the process of clock synchronization between the first node and the second node. The execution node includes a first node and a second node, and the first node and the second node are in different local area networks. The process of executing the clock synchronization algorithm by the execution node may include the following steps: the first node aligns the TSF clock of the first node with the system clock of the first node; the first node sends a first synchronization message to the second node; the second node sends a second synchronization message to the first node; the second node adjusts the TSF clock of the second node according to the clock synchronization parameters; the second node adjusts the system clock of the second node according to the adjusted TSF clock. The time information that needs to be uploaded to the aggregation node by the first node and the second node in the execution node includes: the TSF reception time and TSF sending time of the first synchronization message, the TSF sending time and TSF reception time of the second synchronization message (TSF reception time or TSF sending time refers to the value of the TSF clock read when receiving or sending the message).

FIG11 shows a specific embodiment of the clock synchronization algorithm. As shown in FIG11 , a master node and a slave node may be selected from the nodes that need to be synchronized, and the clock of the slave node may be aligned with the clock of the master node.

Exemplarily, the first node that sends the subscription request message can be the master node, and the second node can be the slave node. The system clock of the first node can be aligned with the TSF clock of the first node first, and then the TSF clock of the second node can be aligned with the TSF clock of the first node, and finally the system clock of the second node can be aligned with the TSF clock of the second node.

For the process of aligning the system clock of the first node with the TSF clock, its system clock can be aligned with the TSF clock, or the TSF clock of the first node can be aligned with the system clock. Taking the alignment of the TSF clock of the first node with the system clock as an example, as shown in S1110 in Figure 11, the first node can read the system clock and the TSF clock respectively and minimize the difference between the system clock and the TSF clock, so as to synchronize the TSF clock to the system clock. In the actual process, there is a certain delay and fluctuation in the reading of the TSF clock or the system clock. The system clock and the TSF clock can be read continuously for multiple times and the minimum reading clock value difference can be selected to reduce the influence of the reading fluctuation. The multiple readings can be periodic or non-periodic readings. For the case of periodic reading, the system clock and the TSF clock can be read according to the clock synchronization cycle (the system clock and the TSF clock are read once in one clock synchronization cycle), or the system clock and the TSF clock can be read multiple times in one clock synchronization cycle.

For example, the difference between T _k+1 and T _k-1 is smaller than the difference between T _k+4 and T _k+2 , and smaller than other read differences. The offset value of the system clock and TSF clock of the first node can be calculated using the set of read data T _k+1 and T _k-1. As shown in the following formula (8):

Afterwards, the TSF clocks of the second node and the first node can be synchronized according to a round of synchronization message interaction in S1120, and the second node synchronizes its TSF clock to the TSF clock of the first node by using a two-way message interaction method. During the synchronization message interaction process, the second node and the first node network card can use the TSF clock to mark the sending time and receiving time of the message. After each round of synchronization message interaction (N rounds of synchronization message interaction in S1120 can correspond to the synchronization message interaction process that needs to be performed in each clock synchronization cycle within N clock synchronization cycles), if the clock frequency deviation between the first node and the second node and the difference in the round-trip communication delay of the synchronization message are not considered, the clock offset value θ _offset of the TSF clocks of the two nodes can be calculated according to the following formula (9):

Wherein, T _1,i is the TSF receiving time of the first synchronization message, T _0,i is the TSF sending time of the first synchronization message, T _3,i is the TSF receiving time of the second synchronization message, T _2,i is the TSF sending time of the second synchronization message, and the TSF sending time of the first synchronization message and the TSF receiving time of the second synchronization message refer to the TSF clock value when the first node sends the first synchronization message and receives the second synchronization message after synchronizing the system clock and the TSF clock. Accordingly, the second node can adjust its TSF clock value to minimize the difference between the TSF clock of the second node and the TSF clock of the first node. Since the system clock and the TSF clock of the first node are synchronized (S1110), the TSF clock of the second node is also synchronized with the system clock of the first node (or the TSF clock of the first node).

If the uncertainty of the one-way communication delay of the synchronization message is considered, the first node and the second node can perform multiple (N) two-way message interactions (first synchronization message and second synchronization message) according to step S1120 of Figure 11. The multiple message interactions can be periodic message interactions or non-periodic message interactions. For periodic message interactions, two-way message interactions can be performed according to the clock synchronization cycle (the interaction of the first synchronization message and the second synchronization message is performed once in a clock synchronization cycle), or N two-way message interactions can be performed in a clock synchronization cycle (the interaction of the first synchronization message and the second synchronization message is performed N times in a clock synchronization cycle). During the i-th message interaction process, the first node sends a first synchronization message to the second node and receives a second synchronization message from the second node. The first node will record the time T _0,i of sending the first synchronization message and the time T _3,i of receiving the second synchronization message, and the second node will record the time T _1,i of receiving the first synchronization message and the time T _2,i of sending the second synchronization message.

In FIG11 , T _0,i and T _3,i are TSF times of the first node, and T _1,i and T _2,i are TSF times of the second node. The TSF clock offset between the first node and the second node is defined as θ _offset . The deterministic part of the one-way message communication delay during the i-th message interaction between the first node and the second node is defined as d. The uncertainty part of the one-way message communication delay is defined as _Xi (the uncertainty part of the communication delay of the first node sending the first synchronization message to the second node) and _Yi (the uncertainty part of the communication delay of the second node sending the second synchronization message to the first node). When the clock drift between the first node and the second node is ignored (the clock frequency deviation is 0), based on the recorded TSF times T _0,i , T _1,i , T _2,i and T _3,i , the clock offset θ _offset between the first node and the second node and the deterministic part d and the uncertainty parts _Xi and _Yi of the one-way message communication delay can be associated by the following equation (10):

T _1,i =T _0,i +θ _offset +d+X _i

T _3,i =T _2,i -θ _offset +d+Y _i (10)

Based on modeling the uncertainty part of the message communication delay between the first node and the second node in the above equation (10), the value of the clock offset θ _offset can be calculated. For example, when the uncertainty part of the message communication delay between the first node and the second node satisfies the normal distribution, the clock offset value θ _offset between the first node and the second node can be calculated according to formula (11):

When the uncertainty of the message communication delay between the first node and the second node satisfies the exponential distribution, the clock offset θ _offset between the first node and the second node can be calculated according to formula (12):

U _i = T _1,i - T _0,i

V _i = T _3,i -T _2,i (12)

When the clock drift between the first node and the second node is considered (the clock frequency deviation is not 0), the clock offset θ _offset and the clock frequency deviation θ _skew between the first node and the second node and the deterministic part d and the uncertain parts _Xi and _Yi of the one-way message communication delay can be associated by the following equation:

T _1,i =T _0,i +θ _offset +d+X _i +θ _skew (T _0,i -T _0,1 +d+X _i )

T _2,i =T _3,i +θ _offset -dY _i +θ _skew (T _3,i -T _0,1 -dY _i ) (13)

Based on the modeling of the uncertainty part of the message communication delay between the first node and the second node in the above equation (13), the values of the clock offset θ _offset and the clock frequency deviation θ _skew can be calculated. For example, when the uncertainty part of the message communication delay between the first node and the second node satisfies the normal distribution, the clock offset θ _offset and the clock frequency deviation θ _skew between the first node and the second node can be calculated according to formula (14):

When the clock synchronization strategy formulated by the control node uses the synchronization method shown in FIG11, the clock synchronization strategy flag in the strategy delivery message can indicate the use of the synchronization algorithm, the execution node identifier can include the local node identifier and the target node identifier in the subscription request message sent by the first node, and the synchronization message type can be: UDP message, TCP message, link layer data frame, etc. The clock synchronization period can be determined based on the clock synchronization period carried in the subscription request message of the first node, the network resource usage and communication status, etc., or can be specified by the system preset value, and the aggregation node identifier can be the identifier of the first node or the second node, or the identifier of other nodes.

Taking the aggregation node as other nodes as an example, the first node can report the time information to the aggregation node. For the i-th message interaction process, the time information upload message can include 4 time information structures, and the "time information type-time information data" are: the first synchronization message sending time-T _0, the first synchronization message receiving time-T ₁ , the second synchronization message sending time-T _2, and the second synchronization message receiving time-T ₃ .

After receiving the time information upload message, the aggregation node can calculate the clock offset value and/or clock frequency deviation of the TSF clock of the first node relative to the TSF clock of the second node, and carry the clock offset value and/or clock frequency deviation together with the first node identifier in a parameter publishing message and send it to the second node, so that the second node can adjust the TSF clock according to the clock offset value and/or clock frequency deviation of the message to achieve synchronization with the TSF clock of the first node.

Finally, the system clock and TSF clock of the second node are synchronized according to S1130. Similar to S1110, by reading the system clock and TSF clock respectively, the second node can synchronize its system clock to the TSF clock. Since the TSF clock of the second node has been synchronized with the system clock of the first node (step S1120), the system clock of the first node will also be synchronized with the system clock of the second node.

Since the TSF clock can be read on the network card firmware side, the uncertainty of system scheduling and protocol stack processing in the synchronization message time information marking process can be reduced, and the accuracy of clock synchronization can be improved. For the interaction of the synchronization message in step S1120 in Figure 11, the second node and the first node will upload the read TSF clock value to the aggregation node, which will calculate the TSF clock offset value of the first node and the second node and publish it to the first node and the second node.

The previous article takes the first node that sends the subscription request message as the master node and the first node sends the first synchronization message as an example to introduce the process of clock synchronization when the first node and the second node are in different WiFi networks. In actual situations, the first node can also be used as a slave node, that is, the second node sends the first synchronization message, and the first node that sends the subscription request message uses the clock synchronization parameters to adjust its TSF clock. In this case, the clock synchronization process is as follows:

The second node aligns the TSF clock of the second node with the system clock of the second node; the second node sends the first synchronization message to the first node; the first node sends the second synchronization message to the second node; the first node adjusts the TSF clock of the first node according to the clock synchronization parameters and the TSF clock of the second node; the first node adjusts the system clock of the first node according to the adjusted TSF clock. Therefore, the time information that needs to be uploaded to the aggregation node by the execution node includes: the TSF receiving time of the first synchronization message and the TSF sending time of the first synchronization message, the TSF receiving time of the second synchronization message and the TSF sending time of the second synchronization message.

The above article introduces the improvement of the WiFi-TSF synchronization scheme of the present application by taking the master node system clock synchronizing with the TSF clock - the slave node synchronizing with the master node TSF clock - the slave node system clock synchronizing with the TSF clock as an example. In practice, the TSF clocks of the two nodes can also be synchronized first, and then the respective system clocks are synchronized with the TSF clock. The embodiments of the present application do not limit the implementation steps of the method.

In an embodiment of the present application, if the computing power, storage capacity, communication capacity and available power of the first node and/or the second node device are relatively limited, and the requirements for clock synchronization accuracy are not high, the execution node determined by the control node may not include the first node and/or the second node. Taking the system of Figure 1 as an example, the first node (device 13) and the second node (device 14) in the local area network 3 need to be clock synchronized, but the hardware configuration of the two nodes is poor. When the control node determines the clock synchronization strategy, the nodes in the local area network 2 can be selected as execution nodes and aggregation nodes. When the execution node clock selected in the local area network 2 is synchronized to the second reference clock value (and/or the second reference clock frequency), the first clock value can be reported to the control node, and the control node carries the second reference clock value (and/or the second reference clock frequency) in the parameter release message and sends it to the first node and the second node. The first node and the second node can each adjust the clock value to a second reference clock value (and/or a second reference clock frequency) to achieve clock synchronization. The second reference clock value (and/or the second reference clock frequency) is the clock synchronization parameter mentioned above, which can be an updated clock value (and/or an updated clock frequency) here.

The control node can instruct the execution nodes in the local area network 2 to use different clock synchronization algorithms for clock synchronization according to the different clock synchronization accuracy requirements between the first node and the second node, so that the execution nodes in the local area network 2 can form a clock synchronization domain, and the clock synchronization parameters between the execution nodes can be calculated by the devices in the local area network 2 or the execution nodes themselves, or can also be uploaded to the remote control node or the cloud, which calculates the clock synchronization parameters. This allows the nodes that need to be synchronized to easily obtain clock synchronization services without executing the clock synchronization algorithm, thereby achieving synchronization of the local clock.

It should be understood that the above only schematically introduces several clock synchronization algorithms through Figures 9 to 11 and Figure 2. In actual situations, according to changes in factors such as communication connections, node configurations, and network resource usage, other different clock synchronization algorithms can also be used, and the embodiments of the present application will not list them one by one.

The clock synchronization method provided in the embodiment of the present application allows the user to participate in the setting and updating. The user can view the clock synchronization method and participate in the detailed setting of the clock synchronization method through the corresponding application on the electronic device.

Exemplarily, the clock synchronization method of the above example can be used for clock synchronization between various devices in the home network. As shown in (a) and (b) of Figure 12, the user can enter the preview interface 1220 of the clock synchronization status of different devices in the home network by clicking the application icon 1211 on the interface 1210 of the electronic device. Schematically, the home network includes devices 1 to 9, wherein device 1 can be a home gateway (optionally, it can be a whole-house smart host or a home storage center), device 2 can be a router, etc., and the local area network connection between device 2 and device 1 can be achieved through, for example, a network cable. Different devices in the home network can be connected to the router directly or different devices can be connected to the router to achieve WiFi-P2P connection, and different devices can also be connected via Bluetooth. The preview interface will show the user the connection status between different devices and the communication medium of the connection, and can also show the user whether the device is online. Schematically, whether a device is online can be displayed by a control near the device icon. The color of the control that displays the device number near device 7 and device 9 in Figure 12 (as shown in control 1221) is different from the color of the control that identifies the device number near other devices (for example, as shown in control 1222). This means that device 7 and device 9 may be offline, for example, device 7 or device 9 may be turned off or out of the home network area.

The user can click on the connection line between the devices to view the synchronization status of the two devices. Exemplarily, the synchronization status between the devices can be displayed by a card popping up on the interface 1220. For example, the user is using device 4 (mobile phone 1) to project the screen on device 3 (the TV in the living room). The user can view the synchronization status by clicking on the connection line 1223 between device 3 and device 4. A card 1224 can pop up on the interface 1220. The card may include the synchronization status of device 3 and device 4, as shown in (c) of Figure 12, such as information such as clock synchronization accuracy, execution nodes, aggregation nodes, and clock synchronization algorithm.

In an embodiment of the present application, the user may be allowed to participate in the setting of the clock synchronization service between devices. For example, when the user uses mobile phone 1 to project the screen on the TV in the living room, and finds that the interface freezes during the projection, the user may, for example, long press control 1223 to enter the setting interface 1230 of the clock synchronization service of device 3 and device 4. Interface 1230 may include multiple setting options for the clock synchronization service. Schematically, (d) of Figure 12 includes setting options such as synchronization period, synchronization algorithm, control node, convergence node, execution node, synchronization accuracy, etc. Interface 1230 will prompt the user with the current synchronization setting, which may be determined or selected by the control node according to the method described above.

In order to alleviate the stuck situation of the screen projection interface, the user can click one or more items on the interface 1230 to change the corresponding synchronization settings. Exemplarily, the user can click on the control 1231 to enter the setting interface 1240 of the clock synchronization cycle. As shown in (e) of Figure 12, in order to facilitate the user's selection, a prompt control 1241 can be displayed to the user on the interface to prompt the user with several aspects of the score of the clock synchronization cycle. For example, the control 1241 can include a delay score, a power saving score and a network score (1 to 10 points respectively). The delay score can be related to the clock synchronization accuracy corresponding to the clock synchronization cycle. The smaller the clock synchronization cycle, the higher the synchronization accuracy, and the higher the delay score; the power saving score can be related to the power consumed by the user using the clock synchronization cycle. This aspect of the score has a certain reference significance for the user when using the mobile terminal for clock synchronization; the network score refers to the occupancy of the network bandwidth corresponding to the clock synchronization cycle. It should be understood that (e) of Figure 12 only schematically shows several scores, and other scores can also be prompted to the user based on other factors to facilitate the user's selection.

In addition, due to the limitations of other clock synchronization factors of device 3 and device 4, such as the limitations of clock synchronization algorithm, execution node, convergence node, and clock synchronization accuracy, only a few of the multiple clock synchronization cycles displayed on interface 1240 may meet the limitations of other current clock synchronization factors. Schematically, the currently used clock synchronization cycle "1s" can be displayed in, for example, a bold font, and the clock synchronization cycles that are allowed to be selected by the user, such as "0.5s" and "2s" can be displayed normally, and the clock synchronization cycles that are not allowed to be selected by the user can be represented by other fonts, such as gray fonts, as shown in "0.1s" and "5s". When the user clicks on the clock synchronization cycle in gray font, a pop-up card can be used to prompt the user why the clock synchronization cycle cannot be selected, such as prompting the user to "Please change the clock synchronization algorithm".

Similarly, the user can click on the control 1232 on the interface 1230 to enter the setting interface 1250 of the clock synchronization algorithm, as shown in (f) of Figure 12. On the interface 1250, the user can change the clock synchronization algorithm, and the display interface of the electronic device will also prompt the user with several ratings for the user to refer to and select the clock synchronization algorithm. For example, the user can be prompted with the user rating, delay rating, power saving rating and network rating through the control 1251. The user rating can be the rating given by the user using the clock synchronization algorithm, and the other three ratings can be calculated or estimated by the R&D personnel or the electronic device according to the network situation, the synchronization situation of the device and the power. The technical solution provided in the embodiment of the present application can also allow the user to import an external clock synchronization algorithm. For example, the user can click on "Import" on the interface 1250 to import the local or cloud clock synchronization algorithm into the execution node and the aggregation node of the clock synchronization service for device 3 and device 4. After using the clock synchronization algorithm, the user can also rate the clock synchronization algorithm for reference when other users select the clock synchronization algorithm.

When the user clicks on other clock synchronization setting options on interface 1230, the interface for setting the clock synchronization period and the clock synchronization algorithm can be referred to, which will not be described in detail here.

In addition to allowing the user to select each setting option of the clock synchronization service individually, the clock synchronization strategy can also be displayed on the interface of the electronic device, which includes the clock synchronization algorithm, clock synchronization accuracy, clock synchronization cycle, convergence node, execution node, etc., and the rating of the packaged clock synchronization strategy can be displayed on the interface for the user to refer to when selecting the clock synchronization strategy. Exemplarily, when the user long presses the control 1223 on the interface 1220, the interface 1260 shown in (g) of Figure 12 may appear, and the interface 1260 may be the packaged clock synchronization strategy, and the user rating of the clock synchronization strategy and the ratings of several aspects may be displayed on the interface 1260, so as to facilitate the user to select the appropriate clock synchronization strategy.

FIG. 13 shows a clock synchronization device 1300 provided in an embodiment of the present application. The clock synchronization device 1300 includes a transceiver unit 1310 and a processing unit 1320 .

In one embodiment of the present application, the clock synchronization device 1300 may be equivalent to the control node in the embodiment shown in Figure 3, and the clock synchronization device 1300 may include a unit for executing the steps performed by the control node in Figure 3. The units in the clock synchronization device 1300 and the above-mentioned other operations and/or functions are respectively for implementing the relevant processes of the method in Figure 3.

Specifically, the clock synchronization device 1300 includes: a transceiver unit 1310, used to receive a subscription request message from a first node, the subscription request message is used to subscribe to the clock synchronization service of the first node and a second node, the second node is a node that performs clock synchronization with the first node; a processing unit 1320, used to determine a policy sending message based on the subscription request message, the policy sending message is used to determine clock synchronization parameters, and the clock synchronization parameters are used for the clock synchronization service.

In an embodiment of the present application, the policy delivery message includes an identifier of a clock synchronization algorithm and an execution node. The transceiver unit 1310 is also used to send the policy delivery message to the execution node so that the execution node can obtain time information during the execution of the clock synchronization algorithm. The time information includes a value or timestamp of a clock counter associated with the execution node sending the synchronization message, and/or the time information includes a value or timestamp of a clock counter associated with the execution node receiving the synchronization message.

In an embodiment of the present application, the policy delivery message also includes an identifier of the aggregation node, and the clock synchronization parameter is determined by the aggregation node based on the time information obtained from the execution node; the transceiver unit 1310 is also used by the control node to send the policy delivery message to the aggregation node.

In the embodiment of the present application, the transceiver unit 1310 is further used to receive the clock synchronization parameter from the aggregation node; and send a parameter publishing message to the first node, wherein the parameter publishing message includes the clock synchronization parameter.

In an embodiment of the present application, the subscription request message includes the identifier of the first node, the identifier of the second node and the clock synchronization accuracy.

In an embodiment of the present application, the policy-sent message also includes at least one of the following: a first clock synchronization cycle, the type of the synchronization message, the communication medium used for transmission of the synchronization message, and a time information marking method of the synchronization message. The first clock synchronization cycle is the period in which the execution node executes the clock synchronization algorithm.

In an embodiment of the present application, the processing unit 1320 is also used to determine the second clock synchronization period according to the length of the confidence interval of the clock value of the first node and the clock synchronization accuracy, or to determine the second clock synchronization period according to the length of the confidence interval of the clock value of the second node and the clock synchronization accuracy, the confidence interval of the clock value of the first node or the confidence interval of the clock value of the second node is determined by the aggregation node according to the clock synchronization parameters; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the first clock synchronization period is the second clock synchronization period; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold and the length of the confidence interval is greater than the clock synchronization accuracy, the second clock synchronization period is less than the first clock synchronization period; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than the first preset threshold and the length of the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period.

In another embodiment of the present application, the clock synchronization device 1300 may be equivalent to the first node in the embodiment shown in Figure 3, and the clock synchronization device 1300 may include a unit for executing the steps performed by the first node in Figures 3, 9 to 11, and each unit in the clock synchronization device 1300 and the above-mentioned other operations and/or functions are respectively for implementing the relevant processes of the methods in Figures 3, 9 to 11.

Specifically, the clock synchronization device 1300 includes: a transceiver unit 1310, used to send a subscription request message to a control node, wherein the subscription request message is used to subscribe to the clock synchronization service of the first node and the second node, and the second node is a node that performs clock synchronization with the first node; the transceiver unit 1310 is also used to receive a policy message from the control node, wherein the policy message is determined by the control node according to the subscription request message, and the policy message includes a clock synchronization algorithm and an identifier of an execution node, and the execution node includes a first node and the second node; a processing unit 1320, used to execute the clock synchronization algorithm according to the policy message; the transceiver unit 1310 is also used to obtain clock synchronization parameters, wherein the clock synchronization parameters are used for the clock synchronization service, and the clock synchronization parameters are determined according to the clock synchronization algorithm.

In an embodiment of the present application, the policy sending message also includes an identifier of a convergence node, and the convergence node is not the first node. The transceiver unit 1310 is also used to: send a time information upload message to the convergence node, and the time information upload message includes time information, and the time information is used by the convergence node to determine the clock synchronization parameters, and the time information includes the value or timestamp of the clock counter associated with the execution node executing the clock synchronization algorithm to send the synchronization message, and/or, the time information includes the value or timestamp of the clock counter associated with the execution node executing the clock synchronization algorithm to receive the synchronization message; receive a parameter release message from the convergence node, and the parameter release message includes the clock synchronization parameters.

In an embodiment of the present application, the subscription request message includes the identifier of the first node, the identifier of the second node and the clock synchronization accuracy.

In an embodiment of the present application, the policy-sent message also includes at least one of the following: a first clock synchronization cycle, the type of the synchronization message, the communication medium used for transmission of the synchronization message, and a time information marking method of the synchronization message. The first clock synchronization cycle is the period in which the execution node executes the clock synchronization algorithm.

In an embodiment of the present application, the transceiver unit 1310 is also used to: receive a second clock synchronization period from the control node; the processing unit 1320 is also used to execute the clock synchronization algorithm according to the second clock synchronization period; wherein the second clock synchronization period is determined by the control node based on the length of the confidence interval of the clock value of the first node and the clock synchronization accuracy, or the second clock synchronization period is determined by the control node based on the length of the confidence interval of the clock value of the second node and the clock synchronization accuracy; the confidence interval of the clock value of the first node and the confidence interval of the clock value of the second node are the roots of the aggregation node Determined according to the clock synchronization parameters; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the first clock synchronization period is the second clock synchronization period; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than the first preset threshold and the length of the confidence interval is greater than the clock synchronization accuracy, the second clock synchronization period is less than the first clock synchronization period; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than the first preset threshold and the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period.

In an embodiment of the present application, the first node and the second node are located in different local area networks, and the time information includes the TSF reception time of the first synchronization message and the TSF sending time of the first synchronization message, the TSF reception time of the second synchronization message, and the TSF sending time of the second synchronization message; the clock synchronization parameters include at least one of the following: the difference between the TSF clock value of the first node and the TSF clock value of the third node and the difference between the TSF clock frequency of the first node and the TSF clock frequency of the third node; the first node executes the clock synchronization algorithm including: the first node receives the first synchronization message from the second node; the first node sends the second synchronization message to the second node; the first node adjusts the TSF clock of the first node according to the clock synchronization parameters; the first node adjusts the system clock of the first node according to the adjusted TSF clock.

In an embodiment of the present application, the execution node also includes a third node, and the time information includes: the time when the first node receives the multiple reference messages and the time when the second node receives the multiple reference messages; the clock synchronization parameters include at least one of the following: the difference between the clock value of the first node and the clock value of the second node and the difference between the clock frequency of the first node and the clock frequency of the second node; or, the clock synchronization parameters include at least one of the following: the difference between the clock value of the first node and the first reference clock value, the difference between the clock value of the second node and the first reference clock value, the difference between the clock frequency of the first node and the first reference clock frequency, and the difference between the clock frequency of the second node and the first reference clock frequency; wherein the processing unit 1320 includes a second transceiver subunit for receiving the multiple reference messages from the third node.

In an embodiment of the present application, the time information also includes the time of sending the multiple reference messages.

FIG14 shows a clock synchronization device provided by an embodiment of the present application. The clock synchronization device 1400 shown in FIG14 may correspond to the clock synchronization device described above or the node (device) in the system in FIG1 . Specifically, the clock synchronization device 1400 may be a specific example of the clock synchronization device in FIG13 . The clock synchronization device 1400 includes: a processor 1420. In an embodiment of the present application, the processor 1420 is used to implement corresponding control management operations. For example, the processor 1420 is used to support the clock synchronization device to perform the method, operation or function of the aforementioned embodiment. Optionally, the clock synchronization device 1400 may also include: a memory 1410 and a communication interface 1430; the processor 1420, the communication interface 1430 and the memory 1410 may be interconnected or interconnected through a bus 1440. Among them, the communication interface 1430 is used to support the clock synchronization device to communicate with the backend system of the service provider, etc., and the memory 1410 is used to store the program code and data of the clock synchronization device. The processor 1420 calls the code or data stored in the memory 1410 to implement the corresponding operation. The memory 1410 may be coupled to the processor or not. The coupling in the embodiment of the present application is an indirect coupling or communication connection between clock synchronization devices, units or modules, which may be electrical, mechanical or other forms, and is used for information exchange between clock synchronization devices, units or modules.

Among them, the processor 1420 can be a central processing unit, a general processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. It can implement or execute various exemplary logic blocks, modules and circuits described in conjunction with the disclosure of this application. The processor can also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a digital signal processor and a microprocessor, etc. The communication interface 1430 can be a transceiver, a circuit, a bus, a module or other types of communication interfaces. The bus 1440 can be a peripheral component interconnect standard (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, only one thick line is used in Figure 14, but it does not mean that there is only one bus or one type of bus.

Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims (39)

1. A clock synchronization method, comprising: The first node sends a subscription request message to the control node, where the subscription request message is used to subscribe to a clock synchronization service between the first node and a second node, where the second node is a node that performs clock synchronization with the first node; The control node determines a policy delivery message according to the subscription request message, wherein the policy delivery message includes a clock synchronization algorithm; The first node acquires a clock synchronization parameter, where the clock synchronization parameter is used for the clock synchronization service and is determined according to the clock synchronization algorithm. 2. The method according to claim 1, wherein the policy delivery message includes an identifier of an execution node, and the method further comprises: The control node sends the policy delivery message to the execution node; The execution node sends a message according to the strategy and executes the clock synchronization algorithm. The clock synchronization parameters are determined based on the time information of the synchronization message sent and/or received by the execution node when executing the clock synchronization algorithm. The time information includes the value or timestamp of the clock counter associated with the execution node sending the synchronization message, and/or the time information includes the value or timestamp of the clock counter associated with the execution node receiving the synchronization message. 3. The method according to claim 2, wherein the policy delivery message further includes an identifier of a sink node, the sink node is not the first node, and before the first node obtains the clock synchronization parameter, the method further includes: The control node sends the policy delivery message to the aggregation node; The execution node sends a time information upload message to the aggregation node, where the time information upload message includes the time information; The sink node determines the clock synchronization parameter according to the clock synchronization algorithm and the time information; The aggregation node sends a parameter publishing message to the first node, where the parameter publishing message includes the clock synchronization parameter. 4. The method according to claim 2, characterized in that The policy delivery message further includes an identifier of a sink node, and the sink node is not the first node. Before the first node acquires the clock synchronization parameter, the method further includes: The control node sends the policy delivery message to the aggregation node; The execution node sends a time information upload message to the aggregation node, where the time information upload message includes the time information; The sink node determines the clock synchronization parameter according to the clock synchronization algorithm and the time information; The aggregation node sends the clock synchronization parameter to the control node; The control node sends a parameter publishing message to the first node, where the parameter publishing message includes the clock synchronization parameter. 5. The method according to claim 2, wherein the policy delivery message further includes an identifier of a sink node, the sink node is the first node, and before the first node obtains the clock synchronization parameter, the method further includes: The execution node sends a time information upload message to the aggregation node, where the time information upload message includes the time information; The first node acquires the clock synchronization parameter, including: The first node determines the clock synchronization parameter according to the time information. 6. The method according to any one of claims 3 to 5, characterized in that the subscription request message includes the identifier of the first node, the identifier of the second node and the clock synchronization accuracy. 7. The method according to claim 6, wherein the policy delivery message further comprises at least one of the following: The first clock synchronization cycle, the type of the synchronization message, the communication medium used for the transmission of the synchronization message, and the time information marking method of the synchronization message. The first clock synchronization cycle is the cycle in which the execution node executes the clock synchronization algorithm. 8. The method according to claim 7, characterized in that the method further comprises: The control node determines the second clock synchronization period according to the length of the confidence interval of the clock value of the first node or the length of the confidence interval of the clock value of the second node and the clock synchronization accuracy; wherein the confidence interval of the clock value of the first node or the confidence interval of the clock value of the second node is determined by the convergence node according to the clock synchronization parameter; The control node sends the second clock synchronization cycle to the execution node; The execution node executes the clock synchronization algorithm according to the second clock synchronization cycle; Among them, when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the first clock synchronization period is the second clock synchronization period; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than the first preset threshold and the length of the confidence interval is greater than the clock synchronization accuracy, the second clock synchronization period is less than the first clock synchronization period; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than the first preset threshold and the length of the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period. 9. The method according to any one of claims 3 to 8, characterized in that The execution node includes the first node and the second node, the first node and the second node are located in different local area networks, and the time information includes a TSF reception time of a first synchronization message, a TSF transmission time of the first synchronization message, a TSF reception time of a second synchronization message, and a TSF transmission time of the second synchronization message; The clock synchronization parameter includes at least one of the following: a difference between a TSF clock value of the first node and a TSF clock value of the second node and a difference between a TSF clock frequency of the first node and a TSF clock frequency of the second node; The execution node executes the clock synchronization algorithm, including: The first node aligns a TSF clock of the first node with a system clock of the first node; The first node sends the first synchronization message to the second node; The second node sends the second synchronization message to the first node; The second node adjusts the TSF clock of the second node according to the clock synchronization parameter; The second node adjusts the system clock of the second node according to the adjusted TSF clock. 10. The method according to any one of claims 3 to 8, characterized in that The execution nodes include the first node, the second node and the third node, and the time information includes: the time when the first node receives the multiple reference messages and the time when the second node receives the multiple reference messages; The clock synchronization parameter includes at least one of the following: a difference between a clock value of the first node and a clock value of the second node and a difference between a clock frequency of the first node and a clock frequency of the second node; or, The clock synchronization parameter includes at least one of the following: a difference between a clock value of the first node and a first reference clock value, a difference between a clock value of the second node and the first reference clock value, a difference between a clock frequency of the first node and a first reference clock frequency, and a difference between a clock frequency of the second node and the first reference clock frequency; The execution node executing the clock synchronization algorithm includes: The third node sends the multiple reference messages to the first node and the second node. 11. The method according to any one of claims 2 to 6, wherein the execution node does not include the first node, the clock synchronization parameter includes a second reference clock value and/or a second reference clock frequency, and the method further comprises: The first node updates the clock of the first node to the second reference clock value and/or the second reference clock frequency according to the clock synchronization parameter. 12. A clock synchronization method, comprising: The first node sends a subscription request message to the control node, where the subscription request message is used to subscribe to a clock synchronization service between the first node and a second node, where the second node is a node that performs clock synchronization with the first node; The first node receives a policy delivery message from the control node, where the policy delivery message is determined by the control node according to the subscription request message, and the policy delivery message includes a clock synchronization algorithm and an identifier of an execution node, where the execution node includes the first node and the second node; The first node sends a message according to the strategy and executes the clock synchronization algorithm; The first node acquires a clock synchronization parameter, where the clock synchronization parameter is used for the clock synchronization service and is determined according to the clock synchronization algorithm. 13. The method according to claim 12, wherein the policy delivery message further includes an identifier of a sink node, and the sink node is not the first node, and the method further includes: The first node sends a time information upload message to the aggregation node, the time information upload message includes time information, the time information is used by the aggregation node to determine the clock synchronization parameter, the time information includes the value or timestamp of the clock counter associated with the execution node executing the clock synchronization algorithm to send the synchronization message, and/or, the time information includes the value or timestamp of the clock counter associated with the execution node executing the clock synchronization algorithm to receive the synchronization message; The first node receives a parameter publishing message from the aggregation node or the control node, where the parameter publishing message includes the clock synchronization parameter. 14. The method according to claim 13, characterized in that the subscription request message includes the identifier of the first node, the identifier of the second node and the clock synchronization accuracy. 15. The method according to claim 13 or 14, characterized in that the policy delivery message further comprises at least one of the following: The first clock synchronization cycle, the type of the synchronization message, the communication medium used for the transmission of the synchronization message, and the time information marking method of the synchronization message. The first clock synchronization cycle is the cycle in which the execution node executes the clock synchronization algorithm. 16. The method according to claim 14, characterized in that the method further comprises: The first node receives a second clock synchronization cycle from the control node; The first node executes the clock synchronization algorithm according to the second clock synchronization period; The second clock synchronization period is determined by the control node according to the length of the confidence interval of the clock value of the first node and the synchronization accuracy, or the second clock synchronization period is determined by the control node according to the length of the confidence interval of the clock value of the second node and the synchronization accuracy; the confidence interval of the clock value of the first node or the confidence interval of the clock value of the second node is determined by the convergence node according to the clock synchronization parameter; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the first clock synchronization period is the second clock synchronization period; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold and the length of the confidence interval is greater than the clock synchronization accuracy, the second clock synchronization period is less than the first clock synchronization period, and when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than a first preset threshold and the length of the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period. 17. The method according to any one of claims 13 to 16, characterized in that The first node and the second node are located in different local area networks, and the time information includes a TSF reception time of the first synchronization message and a TSF transmission time of the first synchronization message, a TSF reception time of the second synchronization message and a TSF transmission time of the second synchronization message; The clock synchronization parameter includes at least one of the following: a difference between a TSF clock value of the first node and a TSF clock value of the second node and a difference between a TSF clock frequency of the first node and a TSF clock frequency of the second node; The first node executing the clock synchronization algorithm includes: The first node receives the first synchronization message from the second node; The first node sends the second synchronization message to the second node; The first node adjusts the TSF clock of the first node according to the clock synchronization parameter; The first node adjusts the system clock of the first node according to the adjusted TSF clock. 18. The method according to any one of claims 13 to 16, characterized in that The execution node further includes a third node, and the time information includes: a timestamp of when the first node receives the plurality of reference messages and a time when the second node receives the plurality of reference messages; The clock synchronization parameter includes at least one of the following: a difference between a clock value of the first node and a clock value of the second node and a difference between a clock frequency of the first node and a clock frequency of the second node; or, The clock synchronization parameter includes at least one of the following: a difference between a clock value of the first node and a first reference clock value, a difference between a clock value of the second node and the first reference clock value, a difference between a clock frequency of the first node and a first reference clock frequency, and a difference between a clock frequency of the second node and the first reference clock frequency; The first node executing the clock synchronization algorithm includes: The first node receives the multiple reference messages from the third node. 19. A clock synchronization method, comprising: The control node receives a subscription request message from a first node, where the subscription request message is used to subscribe to a clock synchronization service between the first node and a second node, where the second node is a node that performs clock synchronization with the first node; The control node determines a policy delivery message according to the subscription request message, wherein the policy delivery message is used to determine clock synchronization parameters, and the clock synchronization parameters are used for the clock synchronization service. 20. The method according to claim 19, wherein the policy delivery message includes a clock synchronization algorithm and an identifier of an execution node, and the method further comprises: The control node sends the policy delivery message to the execution node so that the execution node obtains the time information during the execution of the clock synchronization algorithm. The time information includes the value or timestamp of the clock counter associated with the execution node sending the synchronization message, and/or the time information includes the value or timestamp of the clock counter associated with the execution node receiving the synchronization message. 21. The method according to claim 20, characterized in that The policy delivery message further includes an identifier of a convergence node, and the clock synchronization parameter is determined by the convergence node according to the time information obtained from the execution node; The method further comprises: The control node sends the policy delivery message to the aggregation node. 22. The method according to claim 21, characterized in that the method further comprises: The control node receives the clock synchronization parameter from the aggregation node; The control node sends a parameter publishing message to the first node, where the parameter publishing message includes the clock synchronization parameter. 23. The method according to any one of claims 20 to 22, characterized in that the subscription request message includes the identifier of the first node, the identifier of the second node and clock synchronization accuracy. 24. The method according to any one of claims 21 to 23, wherein the policy delivery message further comprises at least one of the following: The first clock synchronization cycle, the type of the synchronization message, the communication medium used for the transmission of the synchronization message, and the time information marking method of the synchronization message. The first clock synchronization cycle is the cycle in which the execution node executes the clock synchronization algorithm. 25. The method according to claim 24, characterized in that the method further comprises: The control node determines the second clock synchronization period according to the length of the confidence interval of the clock value of the first node and the clock synchronization accuracy, or the control node determines the second clock synchronization period according to the length of the confidence interval of the clock value of the second node and the clock synchronization accuracy, and the confidence interval of the clock value of the first node or the confidence interval of the clock value of the second node is determined according to the clock synchronization parameter; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the first clock synchronization period is the second clock synchronization period; when the absolute value of the difference between the confidence interval and the clock synchronization accuracy is greater than a first preset threshold and the length of the confidence interval is greater than the clock synchronization accuracy, the second clock synchronization period is less than the first clock synchronization period, and when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than the first preset threshold and the length of the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period. 26. A clock synchronization system, comprising: A first node, used to send a subscription request message to the control node, where the subscription request message is used to subscribe to a clock synchronization service between the first node and a second node, where the second node is a node that performs clock synchronization with the first node; A control node, configured to determine a policy delivery message according to the subscription request message, wherein the policy delivery message includes a clock synchronization algorithm; The first node is further used to obtain a clock synchronization parameter, where the clock synchronization parameter is used for the clock synchronization service, and the clock synchronization parameter is determined according to the clock synchronization algorithm. 27. The system according to claim 26, characterized in that the policy delivery message includes an identifier of an execution node, and the system further includes an execution node; The control node is further used to send the policy delivery message to the execution node; The execution node is used to send messages according to the strategy and execute the clock synchronization algorithm. The clock synchronization parameters are determined based on the time information of the synchronization message sent and/or received by the execution node when executing the clock synchronization algorithm. The time information includes the value or timestamp of the clock counter associated with the execution node sending the synchronization message, and/or the time information includes the value or timestamp of the clock counter associated with the execution node receiving the synchronization message. 28. The system according to claim 27, characterized in that the policy delivery message further includes an identifier of a sink node, the sink node is not the first node, and the system further includes a sink node; The control node is further configured to send the policy delivery message to the aggregation node; The execution node is further used to send a time information upload message to the aggregation node, wherein the time information upload message includes the time information; The aggregation node is used to: Determine the clock synchronization parameter according to the time information and the clock synchronization algorithm; A parameter publishing message is sent to the first node, where the parameter publishing message includes the clock synchronization parameter. 29. The system according to claim 27, characterized in that the policy delivery message further includes an identifier of a sink node, the sink node is not the first node, and the system further includes a sink node; The control node is further configured to send the policy delivery message to the aggregation node; The execution node is further used to send a time information upload message to the aggregation node, wherein the time information upload message includes the time information; The aggregation node is used to: Determine the clock synchronization parameter according to the time information and the clock synchronization algorithm; Sending the clock synchronization parameter to the control node; The control node is further used to send a parameter publishing message to the first node, where the parameter publishing message includes the clock synchronization parameter. 30. The system according to claim 27, wherein the policy delivery message further includes an identifier of a sink node, and the sink node is the first node; The execution node is further used to send a time information upload message to the aggregation node, where the time information upload message includes the time information; The first node is specifically used for: The clock synchronization parameter is determined according to the time information. 31. The system according to any one of claims 28 to 30, characterized in that the subscription request message includes the identifier of the first node, the identifier of the second node and clock synchronization accuracy. 32. The system according to claim 31, wherein the policy delivery message further includes at least one of the following: The first clock synchronization cycle, the type of the synchronization message, the communication medium used for the transmission of the synchronization message, and the time information marking method of the synchronization message. The first clock synchronization cycle is the cycle in which the execution node executes the clock synchronization algorithm. 33. The system according to claim 32, wherein the control node is further used for: Determine a second clock synchronization period according to the length of the confidence interval of the clock value of the first node and the clock synchronization accuracy, or determine the second clock synchronization period according to the length of the confidence interval of the clock value of the second node and the clock synchronization accuracy, the confidence interval of the clock value of the first node or the confidence interval of the clock value of the second node being determined by the sink node according to the clock synchronization parameter; Sending the second clock synchronization cycle to the execution node; The execution node is further used to execute the clock synchronization algorithm according to the second clock synchronization cycle; Among them, when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is less than a first preset threshold, the first clock synchronization period is the second clock synchronization period; when the difference between the length of the confidence interval and the clock synchronization accuracy is greater than the first preset threshold and the length of the confidence interval is greater than the clock synchronization accuracy, the second clock synchronization period is less than the first clock synchronization period; when the absolute value of the difference between the length of the confidence interval and the clock synchronization accuracy is greater than the first preset threshold and the length of the confidence interval is less than the clock synchronization accuracy, the second synchronization period is greater than the first clock synchronization period. 34. A system according to any one of claims 28 to 33, characterized in that The execution node includes the first node and the second node, the first node and the second node are located in different local area networks, and the time information includes a TSF reception time of a first synchronization message and a TSF transmission time of the first synchronization message, a TSF reception time of a second synchronization message and a TSF transmission time of the second synchronization message; The clock synchronization parameter includes at least one of the following: a difference between a TSF clock value of the first node and a TSF clock value of the second node and a difference between a TSF clock frequency of the first node and a TSF clock frequency of the second node; The first node is specifically used for: aligning a TSF clock of the first node with a system clock of the first node; Sending the first synchronization message to the second node; The second node is specifically used for: Sending the second synchronization message to the first node; adjusting the TSF clock of the second node according to the clock synchronization parameter; The system clock of the second node is adjusted according to the adjusted TSF clock. 35. A system according to any one of claims 28 to 33, characterized in that The execution nodes include the first node, the second node and the third node, and the time information includes: the time when the first node receives the multiple reference messages and the time when the second node receives the multiple reference messages; The clock synchronization parameter includes at least one of the following: a difference between a clock value of the first node and a clock value of the second node and a difference between a clock frequency of the first node and a clock frequency of the second node; or, The clock synchronization parameter includes at least one of the following: a difference between a clock value of the first node and a first reference clock value, a difference between a clock value of the second node and the first reference clock value, a difference between a clock frequency of the first node and a first reference clock frequency, and a difference between a clock frequency of the second node and the first reference clock frequency; The third node is specifically used to send the multiple reference messages to the first node and the second node. 36. The system according to any one of claims 27 to 31, wherein the execution node does not include the first node, the clock synchronization parameter includes a second reference clock value and/or a second reference clock frequency, and the first node is further used for: According to the clock synchronization parameter, the clock of the first node is updated to the second reference clock value and/or the second reference clock frequency. 37. A clock synchronization device, comprising a processor, the processor being coupled to a memory, the memory being used to store instructions, the instructions being executed by the processor, causing the processor to execute the method according to any one of claims 1 to 11, or causing the processor to execute the method according to any one of claims 12 to 18, or The processor is caused to execute the method according to any one of claims 19 to 25. 38. A computer-readable storage medium, characterized in that it stores computer-executable instructions, which, when executed on a computer, enable the computer to execute the method as described in any one of claims 1 to 11, or enable the computer to execute the method as described in any one of claims 12 to 18, or enable the computer to execute the method as described in any one of claims 19 to 25. 39. A computer program product, characterized in that the computer program product comprises: a computer program code, which, when executed, implements the method according to any one of claims 1 to 11, or implements the method according to any one of claims 12 to 18, or implements the method according to any one of claims 19 to 25.