CN102638324A - Method and device for realizing precise time synchronization - Google Patents
Method and device for realizing precise time synchronization Download PDFInfo
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- CN102638324A CN102638324A CN201210084146XA CN201210084146A CN102638324A CN 102638324 A CN102638324 A CN 102638324A CN 201210084146X A CN201210084146X A CN 201210084146XA CN 201210084146 A CN201210084146 A CN 201210084146A CN 102638324 A CN102638324 A CN 102638324A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
- H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
- H04B10/077—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using a supervisory or additional signal
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/02—Details
- H04J3/06—Synchronising arrangements
- H04J3/0635—Clock or time synchronisation in a network
- H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
- H04J3/0658—Clock or time synchronisation among packet nodes
- H04J3/0661—Clock or time synchronisation among packet nodes using timestamps
- H04J3/0667—Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays
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Abstract
The invention provides a method and device for realizing precise time synchronization. The method comprises the following steps of: transmitting a downlink time delay test message (or an uplink time delay test message) to an optical circulator of a main device through a downlink optical fiber (or an uplink optical fiber) through an optical module of a secondary device, recording transmission time, receiving the downlink time delay test message (or the uplink time delay test message) returned by the optical circulator through the downlink optical fiber (or the uplink optical fiber), recording receiving time, and computing downlink time delay (or uplink time delay) according to the recorded transmission time and the receiving time; and computing to obtain time error between the main device and the secondary device through an IEEE1588 protocol, the uplink time delay and the downlink time delay, and enabling the secondary device to realize the precise time synchronization with the main device according to the time error obtained through computation. Through utilizing the method and device for realizing the precise time synchronization, disclosed by the invention, the influence on time synchronization due to dissymmetric uplink and downlink can be avoided, and the precision of the time synchronization is improved.
Description
Technical field
The present invention relates to network communications technology field, particularly a kind of method and apparatus of realizing exact time synchronization.
Background technology
The IEEE1588 agreement is present unique agreement that can realize that split-second precision is synchronous; As shown in Figure 1; Slave unit carries out message through uplink and downgoing line and main equipment and transmits obtaining being used for four time point T1, T2, T3 and T4 of time synchronized, thereby realizes time synchronized.Concrete message transport process can be referring to Fig. 2, and as shown in Figure 2, this process can comprise:
Main equipment sends the Sync message through downgoing line to slave unit, simultaneously, sends the Followup message of the transmitting time T1 that has the Sync message to slave unit through downgoing line;
After slave unit receives the Sync message, write down the T2 time of advent of this Sync message, and from the Followup message, obtain time T 1, simultaneously, at time point T3, slave unit sends the Delay_Req message through uplink to main equipment;
After main equipment receives the Delay_Req message, write down the T4 time of advent of this Delay_Req message, and T4 is carried in the response message Delay_Resp message sends to slave unit through downgoing line;
Slave unit obtains time T 4 from the Delay_Resp message that receives.
Pass through said process; Slave unit can obtain time point T1, T2, T3 and T4; And obtain circuit time delay PathDelay=((T2-T1)+(T4-T3))/2 and the time difference Offset=((T2-T1)-(T4-T3))/2 between the master-slave equipment between the master-slave equipment according to T1, T2, T3 and T4; Wherein, T2-T1=PathDelay
Down+ Δ ms, T4-T3=PathDelay
On+ Δ sm, wherein PathDelay
DownBe downgoing line time delay, PathDelay
OnBe the uplink time delay, Δ ms is the absolute time difference of slave unit with respect to main equipment, and Δ sm is the absolute time difference of main equipment with respect to slave unit, and Δ ms=-Δ sm, and Offset=((T2-T1)-(T4-T3))/2=((PathDelay is then arranged
Down-PathDelay
On)+(Δ ms-Δ sm))/2=(PathDelay
Down-PathDelay
On)/2+ (2 Δ sm)/2.
Under the ideal situation, the Offset theoretical value should equal Δ sm, promptly needs PathDelay
Down=PathDelay
On, also be that the uplink time delay is identical with the downgoing line time delay.Yet under actual conditions, when especially the up-downgoing circuit was asymmetric, up-downgoing circuit time delay can not guarantee it is identical, and the Offset actual value is not Δ sm thus, thereby causes 1588 timing tracking accuracies obviously to reduce.
Summary of the invention
In view of this, the invention provides a kind of method that realizes exact time synchronization, can avoid the asymmetric influence that time synchronized is brought of up-downgoing circuit, improve the accuracy of time synchronized.
The present invention also provides a kind of device of realizing exact time synchronization, can avoid the asymmetric influence that time synchronized is brought of up-downgoing circuit, improves the accuracy of time synchronized.
In order to achieve the above object, the technical scheme of the present invention's proposition is:
A kind of method that realizes exact time synchronization, this method comprises:
Through downlink optical fiber the ring of light that downgoing line delay testing message sends to the main equipment end is returned device from the optical module of equipment end; After the record transmitting time; Receive the ring of light and return the downgoing line delay testing message that device returns through downlink optical fiber; And behind the record time of reception, calculate the downgoing line time delay based on the transmitting time and the time of reception that write down;
Through uplink optical fibers the ring of light that uplink delay testing message sends to the main equipment end is returned device from the optical module of equipment end; After the record transmitting time; Receive the ring of light and return the uplink delay testing message that device returns through uplink optical fibers; And behind the record time of reception, calculate the uplink time delay based on the transmitting time and the time of reception that write down;
Obtain the time error between main equipment and the slave unit through IEEE1588 agreement and said uplink and downlink circuit time-delay calculation, make slave unit according to the exact time synchronization between time error realization that calculates and the main equipment.
The optical module of said slave unit end returns the ring of light that downgoing line delay testing message sends to the main equipment end to device through downlink optical fiber; After the record transmitting time; Receive the ring of light and return the downgoing line delay testing message that device returns through downlink optical fiber; And after the recorder time, calculate the downgoing line time delay according to transmitting time and the time of reception of record and comprise:
The time synchronized unit of slave unit sends to optical module with downgoing line delay testing message through Mac chip, timestamp unit; By optical module the ring of light that said downgoing line delay testing message sends to the main equipment end is returned device, and send to the transmitting time T1 that the ring of light returns device by timestamp unit record optical module
Down
The ring of light that the optical module of slave unit end receives by the main equipment end returns the downgoing line delay testing message that device returns, and returns the time of reception T2 that device receives said downgoing line delay testing message by the timestamp unit record ring of light
Down
The timestamp unit of slave unit is according to the T1 of record
DownAnd T2
DownCalculate downgoing line time delay PathDelay
Down=(T2
Down-T1
Down)/2.
Said downgoing line time delay is passed through a plurality of PathDelay
DownAverage and obtain.
The optical module of said slave unit end returns the ring of light that uplink delay testing message sends to the main equipment end to device through uplink optical fibers; After the record transmitting time; Receive the ring of light and return the uplink delay testing message that device returns through uplink optical fibers; And after the recorder time, calculate the uplink time delay according to transmitting time and the time of reception of record and comprise:
The time synchronized unit of slave unit sends to optical module with uplink delay testing message through Mac chip, timestamp unit; By optical module the ring of light that said uplink delay testing message sends to the main equipment end is returned device, and send to the transmitting time T1 that the ring of light returns device by timestamp unit record optical module
On
The ring of light that the optical module of slave unit end receives by the main equipment end returns the uplink delay testing message that device returns, and returns the time of reception T2 that device receives said uplink delay testing message by the timestamp unit record ring of light
On
The timestamp unit of slave unit is according to the T1 of record
OnAnd T2
OnCalculate uplink time delay PathDelay
On=(T2
On-T1
On)/2.
Said downgoing line time delay is passed through a plurality of PathDelay
OnAverage and obtain.
The said time error that obtains between main equipment and the slave unit through IEEE1588 agreement and said uplink and downlink circuit time-delay calculation comprises: calculate Offset=(PathDelay according to the IEEE1588 agreement
Down-PathDelay
On)/2+ (2 Δ sm)/2 is with PathDelay
DownAnd PathDelay
OnSubstitution Offset obtains the time error between main equipment and the slave unit.
Said optical module is a single fiber bi-directional co-wavelength optical module.
A kind of device of realizing exact time synchronization, this device comprise main equipment and the slave unit of being made up of time synchronized unit, Mac chip and timestamp unit respectively, and said main equipment comprises that the ring of light returns device, and said slave unit comprises optical module, wherein,
The optical module of slave unit returns the ring of light that downgoing line delay testing message sends to main equipment to device through downlink optical fiber, after the timestamp unit record transmitting time by slave unit; The optical module of slave unit receives the ring of light and returns the downgoing line delay testing message that device returns through downlink optical fiber; And behind the timestamp unit record time of reception by slave unit, the timestamp unit of slave unit calculates the downgoing line time delay according to the transmitting time and the time of reception of record;
The optical module of slave unit returns the ring of light that uplink delay testing message sends to main equipment to device through uplink optical fibers, after the timestamp unit record transmitting time by slave unit; The optical module of slave unit receives the ring of light and returns the uplink delay testing message that device returns through uplink optical fibers; And behind the timestamp unit record time of reception by slave unit, the timestamp unit of slave unit calculates the uplink time delay according to the transmitting time and the time of reception of record;
The timestamp unit of said slave unit is according to obtaining the time error between main equipment and the slave unit through IEEE1588 agreement and said uplink and downlink circuit time-delay calculation, the exact time synchronization between realization and the main equipment.
The optical module of said slave unit returns the ring of light that downgoing line delay testing message sends to main equipment to device through downlink optical fiber, after the timestamp unit record transmitting time by slave unit; The optical module of slave unit receives the ring of light and returns the downgoing line delay testing message that device returns through downlink optical fiber; And behind the timestamp unit record time of reception by slave unit, the timestamp unit of slave unit calculates the downgoing line time delay according to transmitting time and the time of reception of record and comprises:
The time synchronized unit of slave unit sends to optical module with downgoing line delay testing message through Mac chip, timestamp unit; By optical module the ring of light that said downgoing line delay testing message sends to the main equipment end is returned device, and send to the transmitting time T1 that the ring of light returns device by timestamp unit record optical module
Down
The ring of light that the optical module of slave unit end receives by the main equipment end returns the downgoing line delay testing message that device returns, and returns the time of reception T2 that device receives said downgoing line delay testing message by the timestamp unit record ring of light
Down
The timestamp unit of slave unit is according to the T1 of record
DownAnd T2
DownCalculate downgoing line time delay PathDelay
Down=(T2
Down-T1
Down)/2.
The optical module of said slave unit returns the ring of light that uplink delay testing message sends to main equipment to device through uplink optical fibers, after the timestamp unit record transmitting time by slave unit; The optical module of slave unit receives the ring of light and returns the uplink delay testing message that device returns through uplink optical fibers; And behind the timestamp unit record time of reception by slave unit, the timestamp unit of slave unit calculates the uplink time delay according to transmitting time and the time of reception of record and comprises:
The time synchronized unit of slave unit sends to optical module with uplink delay testing message through Mac chip, timestamp unit; By optical module the ring of light that said uplink delay testing message sends to the main equipment end is returned device, and send to the transmitting time T1 that the ring of light returns device by timestamp unit record optical module
On
The ring of light that the optical module of slave unit end receives by the main equipment end returns the uplink delay testing message that device returns, and returns the time of reception T2 that device receives said uplink delay testing message by the timestamp unit record ring of light
On
The timestamp unit of slave unit is according to the T1 of record
OnAnd T2
OnCalculate uplink time delay PathDelay
On=(T2
On-T1
On)/2.
Said optical module is a single fiber bi-directional co-wavelength optical module.
In sum; The method of the realization exact time synchronization that the present invention adopted; Be to be connected the measurement that realizes downgoing line time delay or uplink time delay respectively with downlink optical fiber or uplink optical fibers through return device by the optical module and the ring of light; When having obtained downgoing line time delay and uplink, delay; Said downgoing line time delay and uplink time delay substitution basis are had now in the time error formula that calculates through the IEEE1588 agreement, obtain the precise time error, thereby make slave unit according to the exact time synchronization between time error realization that calculates and the main equipment.Because the inventive method is through with obtaining time error in the time error of the up-downgoing circuit time delay substitution accurately formula; And be not to think the identical time error that obtains of up-downgoing circuit time delay simply; Therefore, also just avoided because the influence that up-downgoing circuit time delay difference is brought time error, especially when the up-downgoing circuit is asymmetric; Avoid the asymmetric influence that time synchronized is brought of up-downgoing circuit, improved the accuracy of time synchronized.
Description of drawings
Fig. 1 uses the networking sketch map for existing IEEE1588;
Fig. 2 transmits sketch map for message between the existing master-slave equipment;
Fig. 3 realizes the workflow diagram of accurate time synchronization method for the present invention;
Fig. 4 realizes the structural representation of exact time synchronization device embodiment one for the present invention;
Fig. 5 realizes the structural representation of exact time synchronization device embodiment two for the present invention.
Embodiment
In order to solve the technical problem that the present invention proposes, the concrete realization of scheme according to the invention comprises:
Through downlink optical fiber the ring of light that downgoing line delay testing message sends to the main equipment end is returned device from the optical module of equipment end; After the record transmitting time; Receive the ring of light and return the downgoing line delay testing message that device returns through downlink optical fiber; And behind the record time of reception, calculate the downgoing line time delay based on the transmitting time and the time of reception that write down; Through uplink optical fibers the ring of light that uplink delay testing message sends to the main equipment end is returned device from the optical module of equipment end; After the record transmitting time; Receive the ring of light and return the uplink delay testing message that device returns through uplink optical fibers; And behind the record time of reception, calculate the uplink time delay based on the transmitting time and the time of reception that write down; Obtain main equipment and from the time error between the equipment through IEEE1588 agreement and said uplink and downlink circuit time-delay calculation, make from equipment realize based on the time error that calculates and main equipment between exact time synchronization.
For making the object of the invention, technical scheme and advantage clearer, the present invention is done to describe in detail further below in conjunction with accompanying drawing and specific embodiment.
Fig. 3 is the workflow diagram of the realization accurate time synchronization method that the present invention adopted.As shown in Figure 3, this flow process comprises:
Step 301: the optical module of slave unit end returns the ring of light that downgoing line delay testing message sends to the main equipment end to device through downlink optical fiber, record transmitting time T1
DownAfter, receive the ring of light and return the downgoing line delay testing message that device returns through downlink optical fiber, and recorder time T 2
DownAfter, according to the T1 of record
DownAnd T2
DownCalculate downgoing line time delay PathDelay
Down
In this step, the present invention who provides in conjunction with Fig. 4 realizes the structural representation of exact time synchronization device embodiment one, and the computational methods of said downgoing line time delay comprise:
The time synchronized unit of slave unit sends to optical module with downgoing line delay testing message through Mac chip, timestamp unit; By optical module the ring of light that said downgoing line delay testing message sends to the main equipment end is returned device, and send to the transmitting time T1 that the ring of light returns device by timestamp unit record optical module
Down
The ring of light that the optical module of slave unit end receives by the main equipment end returns the downgoing line delay testing message that device returns, and returns the time of reception T2 that device receives said downgoing line delay testing message by the timestamp unit record ring of light
Down
The timestamp unit of slave unit is according to the T1 of record
DownAnd T2
DownCalculate downgoing line time delay PathDelay
Down=(T2
Down-T1
Down)/2.
Further,, remove the bigger invalid value of sudden change, can also repeat repeatedly to carry out aforesaid operations in order to obtain accurate more downgoing line time delay, and a plurality of PathDelay to calculating
DownAverage, with average as final downgoing line time delay PathDelay
Down
Step 302: the optical module of slave unit end returns the ring of light that uplink delay testing message sends to the main equipment end to device through uplink optical fibers, record transmitting time T1
OnAfter, receive the ring of light and return the uplink delay testing message that device returns through uplink optical fibers, and recorder time T 2
OnAfter, according to the T1 of record
OnAnd T2
OnCalculate uplink time delay PathDelay
On
In this step, the present invention who provides in conjunction with Fig. 5 realizes the structural representation of exact time synchronization device embodiment two, and the computational methods of said uplink time delay comprise:
The time synchronized unit of slave unit sends to optical module with uplink delay testing message through Mac chip, timestamp unit; By optical module the ring of light that said uplink delay testing message sends to the main equipment end is returned device, and send to the transmitting time T1 that the ring of light returns device by timestamp unit record optical module
On
The ring of light that the optical module of slave unit end receives by the main equipment end returns the uplink delay testing message that device returns, and returns the time of reception T2 that device receives said uplink delay testing message by the timestamp unit record ring of light
On
The timestamp unit of slave unit is according to the T1 of record
OnAnd T2
OnCalculate uplink time delay PathDelay
On=(T2
On-T1
On)/2.
The downgoing line time delay is the same with calculating, and in order to obtain accurate more uplink time delay, removes the bigger invalid value of sudden change, can also repeat repeatedly to carry out aforesaid operations, and a plurality of PathDelay to calculating
OnAverage, with average as final uplink time delay PathDelay
On
Step 303: obtain the time error between main equipment and the slave unit through IEEE1588 agreement and said uplink and downlink circuit time-delay calculation, make slave unit according to the exact time synchronization between time error realization that calculates and the main equipment.
The said time error that obtains between main equipment and the slave unit through IEEE1588 agreement and said uplink and downlink circuit time-delay calculation comprises: calculate Offset=(PathDelay according to the IEEE1588 agreement
Down-PathDelay
On)/2+ (2 Δ sm)/2 is with PathDelay
DownAnd PathDelay
OnSubstitution Offset can obtain the time error between main equipment and the slave unit, thereby makes slave unit according to the exact time synchronization between time error realization that calculates and the main equipment.
Need to prove how to calculate Offset and in background technology, introduced, repeat no more according to the IEEE1588 agreement.
So far, promptly accomplished the whole workflow that the present invention realizes accurate time synchronization method.
Based on said method; The time synchronism apparatus of the present invention that provides in the face of Fig. 4 and Fig. 5 down further describes; Can find out that from Fig. 4 and Fig. 5 this device comprises main equipment and the slave unit of being made up of time synchronized unit, Mac chip and timestamp unit respectively, wherein; Said main equipment comprises that also the ring of light returns device, and said slave unit also comprises optical module.
For Fig. 4; The ring of light that one end of downlink optical fiber connects the main equipment end returns device; After the other end connects the optical module of slave unit end; The optical module of slave unit returns the ring of light that downgoing line delay testing message sends to main equipment to device through downlink optical fiber, after the timestamp unit record transmitting time by slave unit; The optical module of slave unit receives the ring of light and returns the downgoing line delay testing message that device returns through downlink optical fiber; And behind the timestamp unit record time of reception by slave unit; The timestamp unit of slave unit calculates the downgoing line time delay according to the transmitting time and the time of reception of record, specifically can comprise:
The time synchronized unit of slave unit sends to optical module with downgoing line delay testing message through Mac chip, timestamp unit; By optical module the ring of light that said downgoing line delay testing message sends to the main equipment end is returned device, and send to the transmitting time T1 that the ring of light returns device by timestamp unit record optical module
Down
The ring of light that the optical module of slave unit end receives by the main equipment end returns the downgoing line delay testing message that device returns, and returns the time of reception T2 that device receives said downgoing line delay testing message by the timestamp unit record ring of light
Down
The timestamp unit of slave unit is according to the T1 of record
DownAnd T2
DownCalculate downgoing line time delay PathDelay
Down=(T2
Down-T1
Down)/2.
For Fig. 5; The ring of light that one end of uplink optical fibers connects the main equipment end returns device; After the other end connects the optical module of slave unit end; The optical module of slave unit returns the ring of light that uplink delay testing message sends to main equipment to device through uplink optical fibers, after the timestamp unit record transmitting time by slave unit; The optical module of slave unit receives the ring of light and returns the uplink delay testing message that device returns through uplink optical fibers; And behind the timestamp unit record time of reception by slave unit; The timestamp unit of slave unit calculates the uplink time delay according to the transmitting time and the time of reception of record, specifically can comprise:
The time synchronized unit of slave unit sends to optical module with uplink delay testing message through Mac chip, timestamp unit; By optical module the ring of light that said uplink delay testing message sends to the main equipment end is returned device, and send to the transmitting time T1 that the ring of light returns device by timestamp unit record optical module
On
The ring of light that the optical module of slave unit end receives by the main equipment end returns the uplink delay testing message that device returns, and returns the time of reception T2 that device receives said uplink delay testing message by the timestamp unit record ring of light
On
The timestamp unit of slave unit is according to the T1 of record
OnAnd T2
OnCalculate uplink time delay PathDelay
On=(T2
On-T1
On)/2.
When having obtained uplink time delay and downgoing line, delay; The timestamp unit of slave unit is according to obtaining the time error between main equipment and the slave unit through IEEE1588 agreement and said uplink and downlink circuit time-delay calculation, the exact time synchronization between realization and the main equipment.
Need to prove that in the present embodiment, said optical module is a single fiber bi-directional co-wavelength optical module, the said ring of light returns device can be the 1:2 optical splitter.
In a word; The method of the realization exact time synchronization that the present invention adopted; Be connected the measurement that realizes downgoing line time delay or uplink time delay respectively with downlink optical fiber or uplink optical fibers through return device by the optical module and the ring of light; When having obtained downgoing line time delay and uplink, delay; Said downgoing line time delay and uplink time delay substitution basis are had now in the time error formula that calculates through the IEEE1588 agreement, obtain the precise time error, thereby make slave unit according to the exact time synchronization between time error realization that calculates and the main equipment.Because the inventive method is through with obtaining time error in the time error of the up-downgoing circuit time delay substitution accurately formula; And be not to think the identical time error that obtains of up-downgoing circuit time delay simply; Therefore, also just avoided because the influence that up-downgoing circuit time delay difference is brought time error, especially when the up-downgoing circuit is asymmetric; Avoid the asymmetric influence that time synchronized is brought of up-downgoing circuit, improved the accuracy of time synchronized.
Further; The present invention realizes the method for exact time synchronization; Can also repeatedly measure respectively uplink time delay and downgoing line time delay; The average that calculates as final uplink time delay and downgoing line time delay, just make that also up-downgoing circuit time delay value is more accurate, thereby the time error that obtains is more accurate.
Further; The present invention realizes the method for exact time synchronization, need not carry out particular design to equipment inner structure, only returns device through an optical module and the ring of light; Promptly can realize the calculating of uplink and downlink circuit time delay; And then the time synchronized between the realization master-slave equipment, therefore, the inventive method realizes simple.
At last, the inventive method only carries out only extracting and upper and lower circuit time-delay calculation in the synchronously one-sided time of carrying out at slave unit, does not also rely on external time; Therefore; Need not equipment room and cooperate, just make that also measuring process is succinct, and solved the incompatible problem of equipment room function.
The above is merely preferred embodiment of the present invention, and is in order to restriction the present invention, not all within spirit of the present invention and principle, any modification of being made, is equal to replacement, improvement etc., all should be included within the scope that the present invention protects.
Claims (11)
1. a method that realizes exact time synchronization is characterized in that, this method comprises:
Through downlink optical fiber the ring of light that downgoing line delay testing message sends to the main equipment end is returned device from the optical module of equipment end; After the record transmitting time; Receive the ring of light and return the downgoing line delay testing message that device returns through downlink optical fiber; And behind the record time of reception, calculate the downgoing line time delay based on the transmitting time and the time of reception that write down;
Through uplink optical fibers the ring of light that uplink delay testing message sends to the main equipment end is returned device from the optical module of equipment end; After the record transmitting time; Receive the ring of light and return the uplink delay testing message that device returns through uplink optical fibers; And behind the record time of reception, calculate the uplink time delay based on the transmitting time and the time of reception that write down;
Obtain the time error between main equipment and the slave unit through IEEE1588 agreement and said uplink and downlink circuit time-delay calculation, make slave unit according to the exact time synchronization between time error realization that calculates and the main equipment.
2. method according to claim 1; It is characterized in that; The optical module of said slave unit end returns the ring of light that downgoing line delay testing message sends to the main equipment end to device through downlink optical fiber, after the record transmitting time, receives the ring of light and returns the downgoing line delay testing message that device returns through downlink optical fiber; And after the recorder time, calculate the downgoing line time delay according to transmitting time and the time of reception of record and comprise:
The time synchronized unit of slave unit sends to optical module with downgoing line delay testing message through Mac chip, timestamp unit; By optical module the ring of light that said downgoing line delay testing message sends to the main equipment end is returned device, and send to the transmitting time T1 that the ring of light returns device by timestamp unit record optical module
Down
The ring of light that the optical module of slave unit end receives by the main equipment end returns the downgoing line delay testing message that device returns, and returns the time of reception T2 that device receives said downgoing line delay testing message by the timestamp unit record ring of light
Down
The timestamp unit of slave unit is according to the T1 of record
DownAnd T2
DownCalculate downgoing line time delay PathDelay
Down=(T2
Down-T1
Down)/2.
3. method according to claim 2 is characterized in that, said downgoing line time delay is passed through a plurality of PathDelay
DownAverage and obtain.
4. method according to claim 1; It is characterized in that; The optical module of said slave unit end returns the ring of light that uplink delay testing message sends to the main equipment end to device through uplink optical fibers, after the record transmitting time, receives the ring of light and returns the uplink delay testing message that device returns through uplink optical fibers; And after the recorder time, calculate the uplink time delay according to transmitting time and the time of reception of record and comprise:
The time synchronized unit of slave unit sends to optical module with uplink delay testing message through Mac chip, timestamp unit; By optical module the ring of light that said uplink delay testing message sends to the main equipment end is returned device, and send to the transmitting time T1 that the ring of light returns device by timestamp unit record optical module
On
The ring of light that the optical module of slave unit end receives by the main equipment end returns the uplink delay testing message that device returns, and returns the time of reception T2 that device receives said uplink delay testing message by the timestamp unit record ring of light
On
The timestamp unit of slave unit is according to the T1 of record
OnAnd T2
OnCalculate uplink time delay PathDelay
On=(T2
On-T1
On)/2.
5. method according to claim 4 is characterized in that, said downgoing line time delay is passed through a plurality of PathDelay
OnAverage and obtain.
6. method according to claim 1; It is characterized in that the said time error that obtains between main equipment and the slave unit through IEEE1588 agreement and said uplink and downlink circuit time-delay calculation comprises: calculate Offset=(PathDelay according to the IEEE1588 agreement
Down-PathDelay
On)/2+ (2 Δ sm)/2 is with PathDelay
DownAnd PathDelay
OnSubstitution Offset obtains the time error between main equipment and the slave unit.
7. according to each described method in the claim 1 to 6, it is characterized in that said optical module is a single fiber bi-directional co-wavelength optical module.
8. device of realizing exact time synchronization, this device comprises main equipment and the slave unit of being made up of time synchronized unit, Mac chip and timestamp unit respectively, it is characterized in that, and said main equipment comprises that the ring of light returns device, and said slave unit comprises optical module, wherein,
The optical module of slave unit returns the ring of light that downgoing line delay testing message sends to main equipment to device through downlink optical fiber, after the timestamp unit record transmitting time by slave unit; The optical module of slave unit receives the ring of light and returns the downgoing line delay testing message that device returns through downlink optical fiber; And behind the timestamp unit record time of reception by slave unit, the timestamp unit of slave unit calculates the downgoing line time delay according to the transmitting time and the time of reception of record;
The optical module of slave unit returns the ring of light that uplink delay testing message sends to main equipment to device through uplink optical fibers, after the timestamp unit record transmitting time by slave unit; The optical module of slave unit receives the ring of light and returns the uplink delay testing message that device returns through uplink optical fibers; And behind the timestamp unit record time of reception by slave unit, the timestamp unit of slave unit calculates the uplink time delay according to the transmitting time and the time of reception of record;
The timestamp unit of said slave unit is according to obtaining the time error between main equipment and the slave unit through IEEE1588 agreement and said uplink and downlink circuit time-delay calculation, the exact time synchronization between realization and the main equipment.
9. device according to claim 8 is characterized in that, the optical module of said slave unit returns the ring of light that downgoing line delay testing message sends to main equipment to device through downlink optical fiber, after the timestamp unit record transmitting time by slave unit; The optical module of slave unit receives the ring of light and returns the downgoing line delay testing message that device returns through downlink optical fiber; And behind the timestamp unit record time of reception by slave unit, the timestamp unit of slave unit calculates the downgoing line time delay according to transmitting time and the time of reception of record and comprises:
The time synchronized unit of slave unit sends to optical module with downgoing line delay testing message through Mac chip, timestamp unit; By optical module the ring of light that said downgoing line delay testing message sends to the main equipment end is returned device, and send to the transmitting time T1 that the ring of light returns device by timestamp unit record optical module
Down
The ring of light that the optical module of slave unit end receives by the main equipment end returns the downgoing line delay testing message that device returns, and returns the time of reception T2 that device receives said downgoing line delay testing message by the timestamp unit record ring of light
Down
The timestamp unit of slave unit is according to the T1 of record
DownAnd T2
DownCalculate downgoing line time delay PathDelay
Down=(T2
Down-T1
Down)/2.
10. device according to claim 8 is characterized in that, the optical module of said slave unit returns the ring of light that uplink delay testing message sends to main equipment to device through uplink optical fibers, after the timestamp unit record transmitting time by slave unit; The optical module of slave unit receives the ring of light and returns the uplink delay testing message that device returns through uplink optical fibers; And behind the timestamp unit record time of reception by slave unit, the timestamp unit of slave unit calculates the uplink time delay according to transmitting time and the time of reception of record and comprises:
The time synchronized unit of slave unit sends to optical module with uplink delay testing message through Mac chip, timestamp unit; By optical module the ring of light that said uplink delay testing message sends to the main equipment end is returned device, and send to the transmitting time T1 that the ring of light returns device by timestamp unit record optical module
On
The ring of light that the optical module of slave unit end receives by the main equipment end returns the uplink delay testing message that device returns, and returns the time of reception T2 that device receives said uplink delay testing message by the timestamp unit record ring of light
On
The timestamp unit of slave unit is according to the T1 of record
OnAnd T2
OnCalculate uplink time delay PathDelay
On=(T2
On-T1
On)/2.
11. each described device is characterized in that according to Claim 8-10, said optical module is a single fiber bi-directional co-wavelength optical module.
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| CN201210084146.XA CN102638324B (en) | 2012-03-27 | 2012-03-27 | Method and device for realizing precise time synchronization |
| PCT/CN2013/072354 WO2013143385A1 (en) | 2012-03-27 | 2013-03-08 | Calculating time offset |
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| CN201210084146.XA CN102638324B (en) | 2012-03-27 | 2012-03-27 | Method and device for realizing precise time synchronization |
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| CN102638324B (en) | 2014-12-17 |
| WO2013143385A1 (en) | 2013-10-03 |
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