Dynamic clock synchronization method based on bidirectional time delay calibration

Abstract

The invention belongs to the field of communication, and provides a dynamic clock synchronization method based on bidirectional time delay calibration, which is used for solving the problem of insufficient clock synchronization precision between base stations caused by environment change and signal transmission time delay fluctuation in the prior art. In the invention, a master base station sends a local synchronization signal to a slave base station, the slave base station performs synchronization state detection after receiving the synchronization signal, enters an asynchronous state after detection failure, and returns an asynchronous signal to the master base station; the master base station measures the transmission delay between the master base station and the slave base station after receiving the asynchronous signal; meanwhile, environment parameters of the master and slave base stations are monitored in real time through an environment sensor, and the master base station calculates an environment compensation correction value according to the environment parameters of the master and slave base stations; the main base station adjusts a local clock in real time on the basis of the transmission time delay and the environment compensation correction value, and dynamic clock synchronization is achieved; in conclusion, through bidirectional time delay calibration and real-time environment compensation, the clock synchronization precision between the base stations is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the field of communications, and specifically provides a dynamic clock synchronization method based on two-way delay calibration. Background Art

[0002] In 5G communication systems, clock synchronization between base stations is a key factor in ensuring network stability and high-precision positioning. Although traditional clock synchronization methods (such as GPS or Beidou satellite timing) can provide relatively accurate clock signals, they are affected by environmental changes (such as temperature fluctuations, air pressure changes, atmospheric interference, etc.) and delay fluctuations during signal transmission, making it difficult for synchronization accuracy to meet high-precision positioning requirements. In addition, existing clock synchronization technologies have failed to effectively solve the interference caused by these environmental factors, especially when transmitting signals between base stations over long distances and in complex environments.

[0003] Therefore, there is an urgent need for a new clock synchronization technology that can overcome the above problems, provide accurate clock synchronization results, and meet the high-precision requirements between 5G base stations. Summary of the invention

[0004] The purpose of the present invention is to provide a dynamic clock synchronization method based on two-way delay calibration to solve the problem of insufficient clock synchronization accuracy between base stations caused by environmental changes and signal transmission delay fluctuations in the prior art. The present invention can eliminate the delay error caused by environmental factors in real time through two-way delay calibration and environmental compensation mechanism, significantly improve the clock synchronization accuracy between base stations, and meet the needs of high-precision ground positioning.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A dynamic clock synchronization method based on two-way delay calibration, characterized in that it comprises the following steps:

[0007] Step a: The initial synchronization state of the slave base station is set to the synchronization state, and the master base station sends a local synchronization signal to the slave base station;

[0008] Step b: After receiving the synchronization signal from the base station, perform synchronization state detection. If the detection fails, enter the asynchronous state and return the asynchronous signal to the main base station;

[0009] Step c: after the master base station receives the asynchronous signal, the transmission delay between the master base station and the slave base station is measured based on a two-way delay calibration method;

[0010] Step d: monitoring the environmental parameters of the master and slave base stations in real time through environmental sensors, including temperature, humidity, and air pressure; the master base station calculates the environmental compensation correction value according to the environmental parameters of the master and slave base stations;

[0011] Step e: The master base station adjusts the local clock in real time based on the transmission delay and environmental compensation correction value to achieve dynamic clock synchronization.

[0012] Furthermore, in step b, the specific process of synchronization status detection is:

[0013] The synchronization signal sent by the master base station to the slave base station is a 1ms rectangular wave signal. The number of pulses of the rectangular wave signal received by the slave base station within the same time interval is intercepted. If it is the same as the synchronous local signal sent by the master base station, it is determined that the master and slave base stations have achieved clock synchronization. Otherwise, it is determined that the master and slave base station synchronization detection has failed.

[0014] Furthermore, in step c, the specific calculation process of the transmission delay is:

[0015] The master base station sends a synchronization request message to the slave base station, and the message is accompanied by the master base station's local timestamp T1; after receiving the message, the slave base station records the receiving timestamp T2 of the request message and returns the message to the master base station, and the returned message contains the slave base station's local timestamp T3; after receiving the slave base station's reply message, the master base station records the receiving timestamp T4 of the reply message;

[0016] Then the one-way delay calculated by the primary base station is:

[0017]

[0018] Wherein, Δt represents the one-way delay between the master and slave base stations.

[0019] Furthermore, in step d, the environmental compensation correction value is specifically:

[0020]

[0021] Where, ΔT comp represents the environmental compensation correction value, d represents the distance between the master and slave base stations, c represents the speed of light in vacuum; k T , k H , k P They represent the correction coefficients of temperature, humidity and air pressure on propagation delay respectively, and ΔZ, ΔH and ΔP represent the changes of temperature, humidity and air pressure between the master reference and the slave base station respectively.

[0022] Furthermore, in step e, the local clock correction value of the master base station is specifically:

[0023] Δt′=Δt+ΔT comp

[0024] Wherein, Δt′ represents the local clock correction value of the master base station;

[0025] The corrected local clock is:

[0026] T′=T-Δt′

[0027] Wherein, T′ represents the local clock of the master base station after correction, and T represents the local clock of the master base station before correction.

[0028] Based on the above technical solution, the beneficial effects of the present invention are:

[0029] The present invention provides a dynamic clock synchronization method based on two-way delay calibration. Through two-way delay calibration and real-time environmental compensation, the clock synchronization accuracy between base stations is significantly improved, which can meet the needs of high-precision positioning. At the same time, it monitors and adapts to environmental changes (such as temperature, humidity, etc.) in real time, effectively eliminates the delay errors caused by these factors, and ensures the stability of clock synchronization accuracy.

[0030] In summary, the present invention can cope with delay fluctuations in complex environments, and ensure the reliability and stability of clock synchronization through real-time calibration and correction, and is particularly suitable for 5G networks and high-precision positioning services; and the present invention is not only suitable for 5G communication systems, but can also be extended to other communication systems and positioning services that require precise clock synchronization. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a flow chart of the dynamic clock synchronization method based on two-way delay calibration in the present invention.

[0032] Figure 2 It is a system schematic diagram of the master and slave base stations in the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and beneficial effects of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0034] This embodiment provides a clock synchronization method based on two-way delay calibration, the process of which is as follows: Figure 1 As shown; any base station in the communication network has an optical fiber interface connected to its own synchronous base station. A certain base station is selected as the main base station, and any other base station is directly connected to the main base station, that is, the slave base station. Figure 2 As shown in the figure, in order to achieve high-precision clock synchronization, each base station needs to have the following core functional modules:

[0035] High-precision local clock module: The high-precision local clock module is the core of the entire system. Its main function is to generate stable and accurate time signals. Each base station has an internal clock to synchronize communication events in the network. The clock is initially synchronized through Beidou satellites or other timing sources, but the synchronization accuracy is affected by environmental changes and delay fluctuations. After two-way delay calibration, the clock is dynamically adjusted according to the calibration results;

[0036] Bidirectional communication module: Bidirectional delay measurement is performed between base stations through a wired communication network (such as optical fiber or dedicated clock synchronization line). This module can exchange time stamps in real time in the wired network and measure the round-trip delay of signal propagation;

[0037] Environmental monitoring module: The environmental monitoring module is used to collect environmental parameters that affect signal propagation speed in real time. The base station is equipped with environmental sensors to monitor environmental factors such as temperature, humidity, and air pressure that affect latency and clock stability.

[0038] Specifically, any pair of master-slave synchronization base stations performs clock synchronization according to the following steps:

[0039] Step a: The initial synchronization state of the slave base station is set to the synchronization state, and the master base station sends a local synchronization signal to the slave base station;

[0040] Step b: After receiving the synchronization signal from the base station, perform synchronization state detection. If the detection fails, enter the asynchronous state and return the asynchronous signal to the main base station. The specific process of synchronization state detection is as follows:

[0041] The synchronization signal sent by the master base station to the slave base station is a 1ms rectangular wave signal. The number of pulses of the rectangular wave signal received by the slave base station in the same time interval is intercepted. If it is the same as the synchronization local signal sent by the master base station, it is determined that the master and slave base stations have achieved clock synchronization. Otherwise, it is determined that the master and slave base station synchronization detection has failed;

[0042] Step c: After the master base station receives the asynchronous signal (i.e., the slave base station enters the asynchronous state), the transmission delay between the master base station and the slave base station is measured based on the two-way delay calibration method; the specific calculation process of the transmission delay is:

[0043] Delay measurement is performed through accurate timestamp recording. The master base station sends a synchronization request message to the slave base station, and the message is accompanied by the master base station's local timestamp T1. After receiving the message, the slave base station records the receiving timestamp T2 of the request message and returns the message to the master base station. The returned message contains the slave base station's local timestamp T3. After receiving the slave base station's reply message, the master base station records the receiving timestamp T4 of the reply message.

[0044] The primary base station calculates the one-way delay according to the following formula:

[0045]

[0046] Where Δt represents the one-way delay between the master and slave base stations;

[0047] T4-T1 represents the total delay from the primary base station sending the synchronization request message to receiving the reply message, and T3-T2 represents the delay from the base station receiving the synchronization request message to sending the reply message. Through the difference in the above two-way delays, the primary base station can accurately calculate the one-way delay between the primary and slave base stations;

[0048] Step d: monitoring the environmental parameters of the master and slave base stations in real time through environmental sensors, including temperature, humidity, and air pressure; the master base station calculates the environmental compensation correction value according to the environmental parameters of the master and slave base stations;

[0049] Considering the impact of environmental changes (such as temperature, humidity, and air pressure fluctuations) on signal propagation delay, an environmental compensation mechanism is designed to correct the propagation delay. The specific environmental compensation mechanism is:

[0050] Environmental sensors are responsible for real-time monitoring of the environmental parameters (temperature, humidity, and air pressure) of the master and slave base stations. The data sampling frequency is set according to the application scenario, generally 1Hz to 10Hz. Based on the collected environmental data, the propagation delay compensation value of the signal in the current environment is calculated in real time;

[0051] In the environmental compensation model, the expression of the signal propagation delay affected by environmental factors is:

[0052]

[0053] Where, ΔT comp represents the environmental compensation correction value, d represents the distance between the master and slave base stations, c represents the speed of light in vacuum; k T , k H , k P They represent the correction coefficients of temperature, humidity and air pressure on propagation delay, respectively; ΔZ, ΔH and ΔP represent the changes in temperature, humidity and air pressure between the master reference and the slave base station (the absolute value of the difference);

[0054] Correction coefficient k for propagation delay due to temperature, humidity and air pressure T , k H , k P It is known a priori through actual measurements in actual application scenarios; during the communication process, the propagation delay correction value is calculated based on the real-time environmental data;

[0055] Step e: The master base station adjusts the local clock in real time based on the two-way delay measurement result and the environmental compensation correction value. The correction value is specifically:

[0056] Δt′=Δt+ΔT comp

[0057] Wherein, Δt′ represents the local clock correction value of the master base station;

[0058] Then, the corrected local clock is:

[0059] T′=T-Δt′

[0060] Wherein, T′ represents the local clock of the master base station after correction, and T represents the local clock of the master base station before correction.

[0061] The above description is only a specific implementation mode of the present invention. Any feature disclosed in this specification, unless otherwise stated, can be replaced by other alternative features that are equivalent or have similar purposes; all the disclosed features, or all the steps in the methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. A dynamic clock synchronization method based on two-way delay calibration, characterized in that: The following steps are involved: Step a: The initial synchronization state of the slave base station is set to the synchronization state, and the master base station sends a local synchronization signal to the slave base station; Step b: After receiving the synchronization signal from the base station, perform synchronization state detection. If the detection fails, enter the asynchronous state and return the asynchronous signal to the main base station; Step c: after the master base station receives the asynchronous signal, the transmission delay between the master base station and the slave base station is measured based on a two-way delay calibration method; Step d: monitoring the environmental parameters of the master and slave base stations in real time through environmental sensors, including temperature, humidity, and air pressure; the master base station calculates the environmental compensation correction value according to the environmental parameters of the master and slave base stations; Step e: The master base station adjusts the local clock in real time based on the transmission delay and environmental compensation correction value to achieve dynamic clock synchronization.

2. The dynamic clock synchronization method based on two-way delay calibration according to claim 1, characterized in that: In step b, the specific process of synchronization status detection is: The synchronization signal sent by the master base station to the slave base station is a 1ms rectangular wave signal. The number of pulses of the rectangular wave signal received by the slave base station within the same time interval is intercepted. If it is the same as the synchronous local signal sent by the master base station, it is determined that the master and slave base stations have achieved clock synchronization. Otherwise, it is determined that the master and slave base station synchronization detection has failed.

3. The dynamic clock synchronization method based on two-way delay calibration according to claim 1, characterized in that: In step c, the specific calculation process of the transmission delay is: The master base station sends a synchronization request message to the slave base station, and the message is accompanied by the master base station's local timestamp T1; after receiving the message, the slave base station records the receiving timestamp T2 of the request message and returns the message to the master base station, and the returned message contains the slave base station's local timestamp T3; after receiving the slave base station's reply message, the master base station records the receiving timestamp T4 of the reply message; Then the one-way delay calculated by the primary base station is: Wherein, Δt represents the one-way delay between the master and slave base stations.

4. The dynamic clock synchronization method based on two-way delay calibration according to claim 1, characterized in that: In step d, the environmental compensation correction value is specifically: Where, ΔT comp represents the environmental compensation correction value, d represents the distance between the master and slave base stations, c represents the speed of light in vacuum; k T , k H , k P They represent the correction coefficients of temperature, humidity and air pressure on propagation delay respectively, and ΔZ, ΔH and ΔP represent the changes of temperature, humidity and air pressure between the master reference and the slave base station respectively.

5. The dynamic clock synchronization method based on two-way delay calibration according to claim 1, characterized in that: In step e, the local clock correction value of the master base station is specifically: Δt′=Δt+ΔT comp Wherein, Δt′ represents the local clock correction value of the master base station; The corrected local clock is: T′=T-Δt′ Wherein, T′ represents the local clock of the master base station after correction, and T represents the local clock of the master base station before correction.

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