RU2574859C2 - Method and device for implementing automatic compensation for asymmetric delay of 1588 link - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: invention relates to communication. A method and device for implementing compensation asymmetric delay of a 1588 link are provided. The method includes: measuring and calculating a value of an asymmetric delay of a 1588 uplink/downlink; performing asymmetric delay compensation when the value of the asymmetric delay exceeds a set synchronisation offset range; and continuing normal 1588 time synchronisation if the value of the asymmetric delay does not exceed the set synchronisation offset range; and implementing automatic compensation for asymmetric delay of the 1588 link.

EFFECT: enabling adjustment of asymmetric delay automatically and ensuring 1588 time synchronisation quality.

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Description

FIELD OF TECHNOLOGY

This document relates to the field of network clock technology complying with 1588, and in particular, to a method and apparatus for realizing automatic compensation of asymmetric delay of a communication line complying with 1588.

BACKGROUND

With the rapid development of 3rd generation mobile communications network technology (3G), the 1588 time synchronization protocol has attracted increased attention and is increasingly being used in the communications network. The protocol complying with the 1588 standard is constantly used by domestic and foreign operators to perform time synchronization and to gradually replace the use of the Global Positioning System (GPS) for time synchronization.

As shown in FIG. 1, when time synchronization is in accordance with the 1588 standard, the synchronous principle is as follows:

the following formulas can be obtained from FIG. one:

A = t ₂ -t ₁ = Delay + Offset; (one) B = t ₄ -t ₃ = Delay-Offset; (2)

and then the following formulas can be obtained according to the above (1) and (2):

formula for Delay: Delay = (A + B) / 2 = ((t1-t0) + (t3-t2)) / 2;

formula for time offset: Offset = (A-B) / 2 = ((t1-t0) - (t3-t2)) / 2.

Moreover, in the above formulas it is assumed that the time delays of the uplink and downlink are equal. The basis of time synchronization, corresponding to the 1588 standard, is the need for symmetric uplink / downlink transmission delay. If the uplink / downlink transmission is asymmetric, that is, when the delays of the uplink and downlink transmissions are not equal, as shown in FIG. 2, in this case, a protocol complying with the 1588 standard is used to calculate the time offset, and half of the asymmetry error value is not taken into account in the offset value, so it is impossible to accurately adjust the time offset, and the quality of time synchronization is deteriorated. In a situation in which the asymmetric delay is critical, this will ultimately lead to the inability to synchronize time.

To date, mainly for the measurement of the delay of the downlink and uplink in accordance with the 1588 standard, specialized checking tools are used in the prior art. The actual value of the asymmetric delay is measured, and then compensation is performed on the asymmetric delay by the method of compensating the asymmetric delay of 1588 standard. However, not only the method uses labor and materials, but also the device cannot measure the actual asymmetric delay automatically when the communication line changes, thus , reducing the quality of time synchronization.

SUMMARY OF THE INVENTION

The technical problem that should be solved by means of this document is to provide a method and apparatus for realizing automatic compensation of asymmetric delay of a communication line in accordance with 1588 standard, which can correct asymmetric delay automatically and guarantee the quality of time synchronization in accordance with 1588 standard.

In order to solve the aforementioned technical problem, the present document provides a method for implementing the compensation of asymmetric delay of communication lines corresponding to the 1588 standard, comprising the steps of:

measuring and calculating an asymmetric downlink / uplink delay value according to 1588 standard; and

performing asymmetric delay compensation when the asymmetric delay value exceeds the set synchronization bias range; and continue the normal time synchronization of the 1588 standard if the asymmetric delay does not exceed the set synchronization bias range; and implement automatic compensation of the asymmetric delay of the communication line corresponding to the 1588 standard.

Preferably, said steps of measuring and calculating an asymmetric downlink / uplink delay value corresponding to 1588 standard comprise the steps of:

start the calculation of the synchronization time corresponding to the standard 1588;

calculating the time offset for the first time and adjusting the time offset according to the actual delays of the downlink and uplink in accordance with the 1588 standard;

stop the calculation and correction of the time offset and record the time synchronization time stamp corresponding to the 1588 standard, containing: time stamp T1 for sending a synchronization message (Sync), time stamp T2 for receiving a synchronization message (Sync), time stamp T3 for sending a request message regarding the delay (Delay_req) and a time stamp T4 for receiving a request message regarding a delay (Delay_req);

calculate the asymmetric delay according to the formula: D1-D2 = ((T2-T1) - (T4-T3)) / 2;

in which D1 is a downlink delay, and D2 is an uplink delay.

Preferably, in said step of correcting the time offset according to the actual delays of the downlink and uplink according to the 1588 standard, reference is made to:

the formula for calculating the time offset in the protocol corresponding to the 1588 standard is: Offset = ((T2-T1) - (T4-T3)) / 2;

the formula for calculating the time offset, taking into account the actual delays of the downlink and uplink, corresponding to the 1588 standard, is: Offset = ((T2-T1) - (T4-T3)) / 2+ (D2-D1) / 2; and

according to the above two formulas, the time offset after correcting the time offset for the first time can be obtained as: Offset = - (D2-D1) / 2 = (D1-D2) / 2.

Preferably, in said step of performing asymmetric delay compensation, a step is referred to in which: asymmetric delay compensation is performed by using a protocol asymmetry correction principle conforming to 1588 standard.

Preferably, the asymmetric downlink / uplink delay value corresponding to 1588 standard is periodically measured and calculated according to the configured asymmetry measurement period.

In order to solve the above technical problem, the present document proposes a system for implementing the compensation of asymmetric delay of the communication line corresponding to the standard 1588, containing:

an asymmetry measurement module configured to measure and calculate an asymmetric downlink / uplink delay value corresponding to 1588 standard; and

an asymmetry compensation module, configured to perform asymmetric delay compensation when the asymmetric delay value exceeds a predetermined synchronization bias range; and implementing automatic compensation of asymmetric delay of the communication line in accordance with the 1588 standard.

Preferably, the system further comprises:

a device synchronization accuracy configuration module, configured to: configure a time synchronization bias range complying with 1588 standard, that is, a device time synchronization accuracy without asymmetric downlink / uplink delay corresponding to 1588 standard; and

a protocol processing module complying with the 1588 standard, configured to: configure, send and receive a protocol complying with the 1588 standard, processing a time stamp and calculating a time offset.

Preferably, the protocol processing unit complying with the 1588 standard is configured to calculate the time offset for the first time after starting the calculation of the time synchronization complying with the 1588 standard and correcting the time offset according to the actual downlink and uplink delay corresponding to the 1588 standard; pausing the calculation and correction of the time offset, and recording a time synchronization time stamp corresponding to 1588, comprising: a time stamp T1 for sending a synchronization message (Sync), a time stamp T2 for receiving a synchronization message (Sync), a time stamp T3 for sending a request message regarding delays (Delay_req) and a time stamp T4 for receiving a request message regarding delay (Delay_req); and

the asymmetry measurement module is configured to calculate the asymmetric delay according to the formula: D1-D2 = ((T2-T1) - (T4-T3)) / 2; in which D1 is a downlink delay, and D2 is an uplink delay.

Preferably, the system further comprises:

an asymmetry measurement period configuration module configured to configure an asymmetry measurement period; and

the asymmetry measurement module is configured to periodically measure and calculate the asymmetric downlink / uplink delay value corresponding to the 1588 standard according to the asymmetry measurement period configured by the asymmetry measurement period configuration module.

Compared with the prior art, an embodiment of the present document provides a simple and efficient calculation method based on an existing 1588 standard time synchronization algorithm, which measures the asymmetric 1588 downlink / uplink time synchronization delay automatically and solves the problem of that the measurement is carried out by labor resources through a special verification device and that it is necessary to measure Again when the link changes, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings described herein are used to provide further understanding of this document and to formulate part of this application. The illustrated embodiments of this document and its description are used to explain this document, and not to impose inappropriate restrictions on this document. Where:

Figure 1 is a flowchart of a method for calculating a time offset by a protocol conforming to 1588;

Figure 2 is a diagram of the bias that occurs when time synchronization of the Protocol corresponding to the standard 1588, under the influence of asymmetric delay;

FIG. 3 is a flowchart of a method for automatically measuring asymmetric downlink / uplink delay in accordance with 1588, according to one embodiment of the present document.

DETAILED DESCRIPTION OF THE INVENTION

A method for implementing automatic compensation of asymmetric downlink / uplink delay corresponding to 1588 standard of the present embodiment includes the following steps:

in step A, the threshold value of the time synchronization offset of the device is configured;

in step B, a time synchronization calculation complying with 1588 standard begins;

in step C, the time offset value (Offset) is calculated for the first time, and the time offset is adjusted according to the actual delay of the communication line, and the calculation and correction of the time synchronization offset corresponding to the 1588 standard is stopped;

in step D, a time synchronization time stamp corresponding to the 1588 standard is recorded;

at step E, an asymmetric delay is calculated according to the formula: D1-D2 = ((T2-T1) - (T4-T3)) / 2;

in step F, asymmetric delay compensation is automatically performed by using the principle of asymmetric delay compensation in accordance with 1588 if it is detected that the asymmetric delay (D1-D2) exceeds the time synchronization offset range of the device; or else step H is executed;

in step H, in the case where there is no asymmetric delay, it is necessary to continue the usual time synchronization according to the 1588 standard and wait for the next asymmetry measurement period.

In order to make the technical scheme aimed at solving the problem and the advantage of this document more clear and more obvious, in the future, an embodiment of this document is described in detail with reference to the accompanying drawings. It is necessary to illustrate that if there are no contradictions, the embodiments in this application and the features in these embodiments can be combined with each other.

First Embodiment

2, in a time synchronization protocol conforming to 1588, the time offset formula is: Offset = ((T2-T1) - (T4-T3)) / 2, the assumption of this formula is that uplink delays and downlink are equal.

If we consider the delay (D2) of the uplink and the delay (D1) of the downlink, then the actual formula is: Offset = ((T2-T1) - (T4-T3)) / 2+ (02-01) / 2.

Thus, the difference between the time offsets calculated by these two offsets is (D2-D1) / 2.

According to the above, a method for realizing automatic compensation of asymmetric downlink / uplink delay in accordance with 1588 standard of the present embodiment includes the following steps:

in step 1, the time synchronization offset range is configured, that is, the accuracy of the device time synchronization in the case in which there is no asymmetric delay; and the unit of measurement is a nanosecond;

in step 2, the slave clock corresponding to the 1588 standard is configured and the time of the main clock is synchronized;

in step 3, a time synchronization protocol compliant with the 1588 standard is started and the Offset is calculated;

in step 4, the time of the slave hours is adjusted according to the Offset value;

in step 5, it is necessary to stop the time correction of the slave hours according to the Offset value and save the time stamp T1 for sending a synchronization message (Sync) and the time stamp 12 for receiving a Sync message; save the time stamp T3 for sending the request message regarding the delay (Delay_req) and the time stamp T4 for receiving the request message regarding the delay (Delay_req);

in step 6, according to the time synchronization formula corresponding to the 1588 standard, the following is present: T2-T1 = D1 + Offset, T4-T3 = D2-Offset;

after correcting the time offset for the first time, Offset = - (D2-D1) / 2 = (D1-D2) / 2; and this formula is substituted in the above formula:

T2-T1 = (3D1-D2) / 2, T4-T3 = (3D2-D1) / 2;

in step 7, it can be deduced from the above formula that D1-D2 = ((T2-T1) -T4-T3)) / 2;

in step 8, due to hardware limitations, and according to the accuracy of synchronization of the device directly, when the difference between the values of the asymmetric delay D1-D2 exceeds the set range of the synchronization bias, then it is assumed that there is an asymmetric delay, and the compensation of the asymmetric delay is performed by using the asymmetry correction method in protocol complying with 1588.

Second Embodiment

As shown in FIG. 3, a system for implementing automatic compensation for asymmetric downlink / uplink delay according to 1588 standard according to one embodiment of the present document mainly includes the following modules:

a device synchronization accuracy configuration module, mainly responsible for: configuring a time synchronization bias range conforming to the 1588 standard of the device, that is, the device time synchronization accuracy in the absence of any asymmetric downlink / uplink delay corresponding to the 1588 standard;

an asymmetry measurement period configuration module, mainly responsible for: configuring an asymmetry measurement period;

a protocol processing module complying with the 1588 standard, mainly responsible for: configuring, sending and receiving a protocol complying with the 1588 standard, processing the time stamp and calculating the time offset and delay of the communication line;

an asymmetry measurement module, mainly responsible for: periodically measuring the asymmetric downlink / uplink delay value corresponding to 1588 standard according to the configured asymmetry measurement period;

asymmetry compensation module, mainly responsible for: configuring asymmetric delay to compensate for downlink / uplink conforming to 1588 standard;

asymmetry measurement module used for: measuring and calculating an asymmetric downlink / uplink delay value 1558; and

the asymmetry compensation module is used to: perform asymmetric delay compensation when the asymmetric delay value exceeds the set synchronization bias range.

Further, a protocol processing unit complying with the 1588 standard is used to calculate the time offset for the first time after the start of the time synchronization calculation complying with the 1588 standard, and correcting the time offset according to the actual downlink and uplink delays corresponding to the 1588 standard; pausing the calculation and correction of the time offset and recording the time synchronization time stamp corresponding to 1588, including: time stamp T1 for sending a synchronization message (Sync), time stamp T2 for receiving a synchronization message (Sync), time stamp T3 for sending a request message regarding the delay (Delay_req) and the time stamp T4 for receiving a request message regarding the delay (Delay_req); and

the asymmetry measurement module is used to calculate the asymmetric delay according to the formula: D1-D2 = ((T2-T1) - (T4-T3)) / 2.

In particular, the implementation of automatic compensation for asymmetric downlink / uplink delay 1558 according to the present embodiment is as follows:

in step 301, a device time synchronization accuracy range is configured in the case when there is no asymmetric delay by the device synchronization accuracy configuration module;

at 302, the configuration of the asymmetry measurement period is configured by the asymmetry measurement period configuration module;

in step 303, the time offset is calculated by a protocol processing module in accordance with 1588;

in step 304, the asymmetric downlink / uplink time synchronization delay 1558 is regularly calculated by the asymmetry measurement module;

in step 305, the asymmetric delay is automatically compensated by the asymmetry compensation module.

The above description is only preferred embodiments of this document and is not intended to impose limitations on this document. This document may have many other embodiments. Specialists in the prior art can make the appropriate modifications and changes according to this document without departing from the scope and essence of this document. And all these modifications or changes should be embodied in the scope of the attached claims of this document.

Obviously, it will be understood by those skilled in the art that each module or each step mentioned hereinabove can be implemented by a universal computing device, and they can be integrated into a single computing device or distributed on a network composed of a plurality of computing devices. Alternatively, they may be implemented by executable program codes of a computing device. Accordingly, they can be stored in a storage device and implemented by means of a computing device, and in some situations, the steps depicted or described can be performed in a manner different from the above, or each of them is embodied in separate modules of integrated circuits, respectively, or a plurality of modules or steps of this document are embodied in one integrated circuit module, which should be implemented. By this principle, this document is not limited to any particular form of combination of hardware and software.

INDUSTRIAL APPLICABILITY

Since the embodiment of this document is implemented on the basis of the existing hardware device without increasing additional costs, and the increase in software costs is not large, the problem of asymmetry of time synchronization corresponding to the 1588 standard is solved efficiently, and the cost of labor and materials for opening a project Time synchronization complying with the 1588 standard is saved significantly.

Claims (5)

1. A method for implementing compensation of asymmetric delay of a communication line corresponding to the 1588 standard, according to which:
measuring and calculating the value of the asymmetric delay of the downlink / uplink in accordance with 1588, and
performing asymmetric delay compensation when the asymmetric delay value exceeds a predetermined synchronization bias range, and continue normal time synchronization according to 1588 if the asymmetric delay value does not exceed a predetermined synchronization bias range,
moreover, these steps of measuring and calculating the value of the asymmetric delay of the downlink / uplink, corresponding to the standard 1588, contain the steps according to which:
start the calculation of the synchronization time corresponding to the standard 1588,
calculating the time offset for the first time and adjusting the time offset according to the 1588 uplink delay D2 and the 1588 downlink delay D1 by means of a formula for calculating the time offset in the corresponding 1588 protocol according to which the offset = (( T2-T1) - (T4-T3)) / 2, and formulas for calculating the time offset taking into account the uplink delay D2 and the downlink delay D1 corresponding to standard 1588, according to which the offset =
((T2-T1) - (T4-T3)) / 2+ (D2-D1) / 2, and according to the two formulas, the time offset after the correction of the time offset for the first time is obtained as: offset =
- (D2-D1) / 2 = (D1-D2) / 2,
stop the calculation and correction of the time offset and record the time synchronization time stamp corresponding to the 1588 standard, containing: time stamp T1 for sending a synchronization message (Sync), time stamp T2 for receiving a synchronization message (Sync), time stamp T3 for sending a request message regarding the delay (Delay_req) and a time stamp T4 for receiving a request message regarding the delay (Delay_req),
get the following two formulas: T2-T1 = (3D1-D2) / 2 and T4-T3 = (3D2-D1) / 2 by substituting the formula according to which the offset = - (D2-D1) / 2 = (D1-D2) / 2, in the time synchronization formulas according to the 1588 standard, according to which T2-T1 = D1 + Displacement and T4-T3 = D2-Displacement,
derive a formula for asymmetric delay as: D1-D2 = ((T2-T1) - (T4-T3)) / 2 according to the two formulas, according to which T2-T1 = (3D1-D2) / 2 and T4-T3 = ( 3D2-D1) / 2. 2. The method according to p. 1, according to which, at the indicated step of performing asymmetric delay compensation, reference is made to the step according to which asymmetric delay compensation is performed by using the principle of asymmetric correction of a protocol in accordance with 1588 standard. 3. The method of claim 1, wherein the asymmetric downlink / uplink delay value corresponding to 1588 standard is periodically measured and calculated according to the configured asymmetry measurement period. 4. A system for implementing compensation of asymmetric delay of a communication line corresponding to the 1588 standard, comprising:
an asymmetry measurement module configured to measure and calculate an asymmetric downlink / uplink delay value corresponding to 1588 standard, and
asymmetry compensation module, configured to perform asymmetric delay compensation when the asymmetric delay value exceeds a predetermined synchronization bias range,
a device synchronization accuracy configuration module, configured to: configure a time synchronization bias range conforming to 1588 standard, that is, a device time synchronization accuracy without asymmetric downlink / uplink delay conforming to 1588 standard, and
a protocol processing module complying with the 1588 standard, configured to: configure, send and receive a protocol complying with the 1588 standard, processing a time stamp and calculating a time offset,
moreover, the processing module of the Protocol corresponding to the standard 1588, is configured to:
calculating the time offset for the first time after the start of the time synchronization calculation complying with the 1588 standard, and adjusting the time offset according to the uplink delay D2 and the downlink delay D1 according to the 1588 standard by the formula for calculating the time offset in the corresponding standard 1588 protocol, according to which offset = ((T2-T1) - (T4-T3)) / 2, and formulas for calculating the time offset taking into account upstream delay D2 and downstream delay D1, corresponding to standard 1588 communication, according to which the offset = ((T2-T1) - (T4-T3)) / 2+ (D2-D1) / 2, and according to the two formulas, the time offset after correcting the time offset for the first time is obtained as: offset = - (D2-D1) / 2 = (D1-D2) / 2, and
pausing the calculation and correcting the time offset and recording the time synchronization time stamp corresponding to 1588, comprising: time stamp T1 for sending a synchronization message (Sync), time stamp T2 for receiving a synchronization message (Sync), time stamp T3 for sending a request message regarding the delay (Delay_req) and the time stamp T4 for receiving a request message regarding the delay (Delay_req), and the asymmetry measurement module is configured to calculate the asymmetric delay by the formula D1-D2 = ((T2-T1) - (T4-T3)) / 2 by obtaining two formulas according to which T2-T1 = (3D1-D2) / 2 and T4-T3 = (3D2-D1) / 2, by substituting the formula according to which the offset = - (D2-D1) / 2 = (D1-D2) / 2, in the time synchronization formulas according to the 1588 standard, according to which T2-T1 = D1 + Displacement and T4-T3 = D2-Displacement, and by deriving the formula for asymmetric delay as: D1-D2 = ((T2 -T1) - (T4-T3)) / 2 according to the above two formulas, according to which T2-T1 = (3D1-D2) / 2 and T4-T3 = (3D2-D1) / 2. 5. The system of claim 4, further comprising:
an asymmetry measurement period configuration module configured to configure an asymmetry measurement period, and
moreover, the asymmetry measurement module is configured to periodically measure and calculate the asymmetric downlink / uplink delay value corresponding to the 1588 standard according to the asymmetry measurement period configured by the asymmetry measurement period configuration module.

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