CN105915308A - Time synchronization method, device and system - Google Patents
Time synchronization method, device and system Download PDFInfo
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- CN105915308A CN105915308A CN201610539966.1A CN201610539966A CN105915308A CN 105915308 A CN105915308 A CN 105915308A CN 201610539966 A CN201610539966 A CN 201610539966A CN 105915308 A CN105915308 A CN 105915308A
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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
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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
- H04J3/0685—Clock or time synchronisation in a node; Intranode synchronisation
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Abstract
The application discloses a time synchronization method, a time synchronization device and a time synchronization system. The method comprises the following steps: sending a time synchronization request to target equipment, receiving a response data package returned by the target equipment and containing a transmitting timestamp, determining transmission time spent from sending the time synchronization request to receiving the data package, determining a transmission time threshold value according to a preset time error scope and expected probability falling into the time error scope, and judging whether the transmission time is shorter than the transmission time threshold value, and if the transmission time is shorter than the transmission time threshold value, correcting the time of the synchronization equipment according to the transmission time and the sending timestamp of the response data package. The application records the influence of transmission time, so that the finally corrected time of the synchronization equipment is more accurate.
Description
Technical field
The application relates to Time synchronization technique field, more particularly, it relates to a kind of method for synchronizing time,
Apparatus and system.
Background technology
Time synchronized can also be referred to as " to clock ", will in system the clock of each equipment with in system
The standard time clock alignment set.
Being of wide application of time synchronized, relatively common needs and application server such as applications client
Between carry out time synchronized.Prior art is when carrying out time synchronized, by applications client to application service
Time synchronized request initiated by device, using application server current time as anti-when application server receives request
Feedforward information is back to applications client, applications client using the current time in feedback information as standard time
Between carry out " to clock ".
Owing to feedback information cannot be measured to the time that applications client is spent from application server transmission,
And network delay is generally within thousand milliseconds of ranks, therefore prior art have ignored what network delay was brought
Error.This solution can be applicable to major part requires it is not the highest application service to time synchronized.
But, along with time precision is required more and more higher by application, prior art cannot be applicable to high accuracy
The requirement of time synchronized.
Summary of the invention
In view of this, this application provides a kind of method for synchronizing time, Apparatus and system, for offer one
Plant precise synchronization scheme.
To achieve these goals, it is proposed that scheme as follows:
A kind of method for synchronizing time, including:
Time synchronized request is sent to target device；
Receive the reply data bag comprising transmission timestamp that described target device returns；
Determine and ask to receive the transmission that described reply data bag is spent from sending out described time synchronized
Time；
According to default time error scope and the expected probability falling into this time error scope, determine transmission
Time threshold；
Judge that whether the described transmission time is less than described transmission time threshold；
If so, according to described transmission time and the transmission timestamp of described reply data bag, correct described same
The time of step equipment.
A kind of time synchronism apparatus, including:
Synchronization request transmitting element, for sending time synchronized request to target device；
Time bag receives unit, for receiving the response comprising transmission timestamp that described target device returns
Packet；
The transmission time determines unit, is used for determining and asks to receive described from sending out described time synchronized
The transmission time that reply data bag is spent；
Transmission time threshold determines unit, is used for according to the time error scope preset and falls into this time by mistake
The expected probability of difference scope, determines transmission time threshold；
Threshold decision unit, is used for judging that whether the described transmission time is less than described transmission time threshold；
Correction time determines unit, is used for when the judged result of described threshold decision unit is for being, according to
Described transmission time and the transmission timestamp of described reply data bag, correct the time of described synchronizer.
A kind of clock synchronization system, including at least one synchronizer and at least one target device, described
The clock of target device is standard time clock；
Described synchronizer is used for, and sends time synchronized request to described target device；Receive described target
What equipment returned comprises the reply data bag sending timestamp；Determine from sending out the request of described time synchronized
To receiving the transmission time that described packet is spent；According to default time error scope and fall into this
The expected probability of time error scope, determines transmission time threshold；Judge whether the described transmission time is less than
Described transmission time threshold；If so, according to described transmission time and the transmission time of described reply data bag
Stamp, corrects the time of described synchronizer；
Described target device is used for, when receiving the time synchronized request that described synchronizer sends, according to
Self current time determines transmission timestamp, returns to described synchronizer and comprises described transmission timestamp
Reply data bag.
The method for synchronizing time that the embodiment of the present application provides includes: synchronizer sends the time to target device
Synchronization request, receive described target device return comprises send timestamp reply data bag, determine from
Send out described time synchronized to ask to receive the transmission time that described reply data bag is spent, according to
The time error scope preset and the expected probability falling into this time error scope, determine transmission time threshold,
Judge that whether the described transmission time is less than described transmission time threshold；If so, according to the described transmission time and
The transmission timestamp of described reply data bag, corrects the time of described synchronizer.As can be seen here, this Shen
Please correct synchronizer time time, it is contemplated that send time synchronized request to receive reply data bag this
The transmission time of individual process, and the transmission timestamp of the reply data bag of target device return.The application
Note and the impact of transmission time so that the time of the synchronizer finally determined is more accurate.
Further, the application is general according to default time error scope and the expectation falling into this time error scope
Rate, determines transmission time threshold, and utilizes this transmission time threshold to choose the transmission time meeting condition.
It is easy to user flexibility and controls the precision of time synchronized and the time-consuming of time synchronization process.
Accompanying drawing explanation
In order to be illustrated more clearly that the embodiment of the present application or technical scheme of the prior art, below will be to reality
Execute the required accompanying drawing used in example or description of the prior art to be briefly described, it should be apparent that below,
Accompanying drawing in description is only embodiments herein, for those of ordinary skill in the art, not
On the premise of paying creative work, it is also possible to obtain other accompanying drawing according to the accompanying drawing provided.
Fig. 1 is the schematic diagram that a kind of synchronizer and the target device of the application example carries out time synchronized；
Fig. 2 is a kind of method for synchronizing time flow chart disclosed in the embodiment of the present application；
Fig. 3 be the application example different RTT under the probability density curve schematic diagram of t1-t2；
Fig. 4 is a kind of method flow diagram determining transmission time threshold disclosed in the embodiment of the present application；
Fig. 5 is a kind of time synchronism apparatus structural representation disclosed in the embodiment of the present application；
Fig. 6 is the hardware architecture diagram of a kind of synchronizer disclosed in the embodiment of the present application.
Detailed description of the invention
Below in conjunction with the accompanying drawing in the embodiment of the present application, the technical scheme in the embodiment of the present application is carried out
Clearly and completely describe, it is clear that described embodiment is only some embodiments of the present application, and
It is not all, of embodiment.Based on the embodiment in the application, those of ordinary skill in the art are not doing
Go out the every other embodiment obtained under creative work premise, broadly fall into the scope of the application protection.
Inventor finds by existing Time Synchronizing carries out research, existing time synchronized side
Case have ignored data and propagate time consuming impact in a network, thus cause time synchronized accuracy
The highest.And along with terminal and the development of application, the requirement to timing tracking accuracy is more and more higher, existing
Time Synchronizing cannot be adapted to the requirement of current precise synchronization.Illustrate such as, many
In people's interactive movie project, movie player and multiple terminals need to show interactive interface simultaneously, synchronize
Timing, disappears simultaneously, requires high to the timing tracking accuracy of each terminal, existing Time Synchronizing
This scene cannot be applicable to.
To this end, this application provides a kind of high-precision method for synchronizing time.
The method for synchronizing time of the application is applied to clock synchronization system, and system comprises at least one synchronization and sets
Standby and at least one target device.Wherein, synchronizer is the equipment of pending time synchronized, and target sets
Standby is the equipment as time source, and its clock is standard time clock.In actual application, synchronizer can be
Mobile phone, IPAD, notebook etc. possess the electronic equipment of network access facility.General, time synchronized
Request can be that certain application installed in synchronizer is initiated.It is of course also possible to be synchronizer
Operating system initiate.
Target device can be server, such as target device be in synchronizer initiate time synchronized request
The application server corresponding to intended application, or for intended application provide service transfer server
Deng.Certainly, target device can also be the electronic equipment such as mobile phone, notebook.
Synchronizer and target device can set according to specific needs.
In the Time Synchronizing of the application, target device is used for, and is receiving the time that synchronizer sends
During synchronization request, return to described synchronizer and comprise the reply data bag sending timestamp；
Wherein, described reply data bag send timestamp be target device determine for the time of carrying out with
The timestamp that sends of the time response packet of step can be that target device receives the request of described time synchronized
Time, it is also possible to be, after target device receives the request of described time synchronized, to return the time of reply data bag.
Certainly, time-consuming compared to Internet communication, target device is from receiving time synchronized request to sending response
The process time of packet is extremely short, can ignore this fractional error.
Synchronizer is used for, and sends time synchronized request to described target device；Receive described target device
Return comprises the reply data bag sending timestamp, determines and asks to connect from sending out described time synchronized
Receive the transmission time that described reply data bag is spent；According to default time error scope and fall into this
The expected probability of time error scope, determines transmission time threshold；Judge whether the described transmission time is less than
Described transmission time threshold；If so, according to described transmission time and the transmission time of described reply data bag
Stamp, corrects the time of described synchronizer, to be allowed to keep consistent with the time of described target device.
See a kind of synchronizer that Fig. 1, Fig. 1 are the application example and carry out time synchronized with target device
Schematic diagram.
In Fig. 1, with synchronizer as web front end, target device as server as a example by illustrate.
As shown in Figure 1:
Web front end initiates time synchronized request, query time in the To moment to server.Owing to network passes
Broadcasting time-consuming existence, the time of server time of receipt (T of R) synchronization request is the Ts moment, deposits between To and Ts
Time at t1.Owing to server operation required time is within 1ms, relative to the net of 100ms magnitude
The network time is negligible, and therefore the application sets the reply data bag that server feeds back to web front end
Transmission timestamp be Ts.Due to the existence of network time, web front end receives the time of reply data bag
For the Ts' moment, between Ts and Ts', there is the time of t2.
Wherein, cannot directly determine for t1 and t2, and overall transmission time RTT (i.e. t1+t2)
May determine that.
It will be further understood that RTT is the least means that time synchronization error is the least, time synchronized mistake
The total time that journey is consumed will be the biggest.
The application can be preset time error scope by user and fall into the phase of this time error scope
Hope probability, and then determine therefrom that transmission time threshold.Synchronizer is when judging certain transmission once determined
Between less than described transmission time threshold time, according to this time transmission the time and target device return answer number
According to bag transmission timestamp, correct the time of described synchronizer, be allowed to described target device time
Between keep consistent.
Owing to synchronizer is when correction time, it is contemplated that send time synchronized and ask to receiving reply data
Wrap the transmission time of this process, and the transmission timestamp of the reply data bag of target device return, also
I.e. synchronizer note and the time-consuming impact of Internet communication so that the time of correction of a final proof is more accurate.
Further, the application is general according to default time error scope and the expectation falling into this time error scope
Rate, determines transmission time threshold, and utilizes this transmission time threshold to choose the transmission time meeting condition.
It is easy to user flexibility and controls the precision of time synchronized and the time-consuming of time synchronization process.
It follows that scheme is introduced by the application with the angle of synchronizer.
Seeing Fig. 2, Fig. 2 is a kind of method for synchronizing time flow chart disclosed in the embodiment of the present application.
As in figure 2 it is shown, the method includes:
Step S200, to target device send time synchronized request；
Specifically, synchronizer determine need to carry out time synchronized time, to target device send the time with
Step request.Time synchronized request can be to be the form transmission with message or packet.Time synchronized request can
To be a segment identification, code or other form.
It is understood that time-consuming in order to reduce Internet communication, can reduce shared by time synchronized request
Data volume.
Step S210, receive described target device return comprise send timestamp reply data bag；
Wherein, described reply data bag send timestamp be described target device determine for carrying out time
Between synchronize time.Sending timestamp can be the time that target device receives the request of described time synchronized,
It can also be the time obtained after target device time of receipt (T of R) synchronization request union.
It is understood that time-consuming in order to reduce Internet communication, the size of reply data bag can be reduced.
Such as, transmission timestamp is placed on the header part of reply data bag, by the main part of reply data bag
Leave a blank, to reduce the transmission time of time bag.
Step S220, determine and ask to receive described reply data bag institute from sending out described time synchronized
The transmission time spent；
Specifically, the time receiving described reply data bag and the time sending the request of described time synchronized
Difference is transmission time RTT.
Step S230, according to the time error scope preset with fall into the expected probability of this time error scope,
Determine transmission time threshold；
Specifically, user can set oneself patient time error scope, and by time error
Control the expected probability in the range of described time error.It is understood that time error scope is the least,
Expected probability is the highest, then corresponding transmission time RTT is the least.Synchronizer is sent to target device
The number of times of time synchronized request is the most, and the total time that time synchronization process consumes is the longest.
In the present embodiment, can be according to default time error scope and the phase falling into this time error scope
Hope that probability determines transmission time threshold.
Step S240, judge that the described transmission time is whether less than described transmission time threshold；If so, perform
Step S250, performs step S200 if it is not, return；
Step S250, according to described transmission time and the transmission timestamp of described reply data bag, correct institute
State the time of synchronizer.
Specifically, according to described transmission time and the transmission timestamp of reply data bag in this step, right
Synchronizer current time is corrected, to be allowed to keep consistent with the time of described target device.
In the embodiment of the present application, synchronizer sends time synchronized request to target device, receives described mesh
Marking device return comprise send timestamp reply data bag, determine from send out described time synchronized please
Ask and receive the transmission time that described reply data bag is spent, according to default time error scope and
Fall into the expected probability of this time error scope, determine transmission time threshold, it is judged that the described transmission time is
No less than described transmission time threshold；If so, according to described transmission time and the described very first time, correction
The time of described synchronizer, to be allowed to keep consistent with the time of described target device.As can be seen here,
The application is when correcting the time of synchronizer, it is contemplated that sends time synchronized and asks to receiving reply data
Wrap the transmission time of this process, and the transmission timestamp of the reply data bag of target device return.This
Application note and the impact of transmission time so that the time of the synchronizer finally determined is more accurate.
Further, the application is general according to default time error scope and the expectation falling into this time error scope
Rate, determines transmission time threshold, and utilizes this transmission time threshold to choose the transmission time meeting condition.
It is easy to user flexibility and controls the precision of time synchronized and the time-consuming of time synchronization process.
Optionally, synchronizer determines that the process of transmission time can have multiple way of realization, such as:
The transmission timestamp of time synchronized request described in synchronizer record, and, record described answer number
Reception timestamp according to bag.
Wherein, the transmission timestamp of described time synchronized request is, and synchronizer sends time synchronized please
The time asked.The reception timestamp of reply data bag is, and synchronizer receives the time of reply data bag.
Based on this, synchronizer according to record described time synchronized request transmission timestamp and described should
Answer the difference receiving timestamp of packet, determine the transmission time.
The timestamp that receives of reply data bag deducts the transmission timestamp of time synchronized request, when being transmission
Between.
For another example,
Synchronizer, while sending time synchronized request to target device, starts timer, initially opens
Time dynamic, timer reading is zero.
Synchronizer, while receiving the reply data bag that described target device returns, terminates described timing
Device.
Based on this, synchronizer can determine transmission according to the timing result of the described timer after terminating
Time.That is, the reading of timer after synchronizer will terminate is defined as the transmission time.
Present inventor is by the research to transmission time RTT, when finding the size pair of transmission time RTT
Between synchronization accuracy produce certain impact.Now the research process of inventor is introduced.
In this application, it is assumed that:
:
RTT → 0 (i.e. RTT level off to 0),
Time:
(t1-t2)≈0
It is to say, when RTT level off to 0 time, can be considered t1=t2.
This inference can simply be interpreted as: when RTT (t1 and t2 sum) is the least when, it is meant that t1
The least with t2 itself (absolute figure), then the gap (absolute figure) between them is the least.
Simple proof is as follows:
Assuming under real network environment, t1 Yu t2 obeys Stochastic Poisson distribution, then RTT (i.e. t1+t2)
Also obeying Poisson distribution, the probability distribution of t1-t2 is as shown in Figure 3.
Can be found out intuitively by Fig. 3, when RTT (i.e. t1+t2) is the least, the probability density curve of (t1-t2) is more
" high thin ", i.e. (t1-t2) fall the highest at the probability that (-50ms, 50ms) is interval, i.e. the difference of t1 Yu t2 is more
Little.When (t1-t2) falls when (-50ms, 50ms) is interval, it is meant that if by supposing t1=t2=1/2
0.5*RTT calculates, and its error is less than 25ms (10ms rank).
In figure 3 it can be seen that as RTT=500ms, there are about the probability (t1-t2) of 70% fall (-50ms,
50ms) in interval, at RTT=1000ms, this probability is only less than 50%.
Understand based on above-mentioned introduction, when transmission time RTT more hour, the probability of t1=t2 is the highest, therefore this
When application synchronizer corrects synchronizer according to the transmission timestamp of transmission time RTT with reply data bag
Between process may is that
Synchronizer is by described transmission time RTT and the product setting coefficient a, with described reply data bag
Transmission timestamp is added, and addition result is defined as the time of synchronizer.
Wherein, setting coefficient a can be preferably 0.5, and it can also is that other numerical value certainly, the value of a
Scope can be (0,1].
Owing to the transmission time is the least, the time that correction of a final proof obtains is the most accurate, may determine that for this application
Transmission time threshold, determining the transmission time less than time when setting transmission time threshold just based on described transmission
Between and the transmission timestamp of described reply data bag, the time of correction synchronizer.
The above embodiments of the present application are it is stated that can be according to default time error scope with when falling into this
Between the expected probability of range of error determine transmission time threshold.It follows that to determining transmission time threshold
Process is introduced.
For the ease of statement, the application define the transmission time include described time synchronized ask from described synchronization
Equipment sends the first transmission sub-time spent to described target device, and described reply data bag is from described
Target device sends the second transmission sub-time spent to described synchronizer.First transmission sub-time is permissible
Regarding above-mentioned t1 as, the second transmission sub-time was considered as above-mentioned t2.
Then determine that the process of transmission time threshold may refer to Fig. 4.
As shown in Figure 4, this process includes:
Step S400, the function distribution obeyed according to the transmission time, determine under the different transmission time first
Transmit the probability density function of sub-time and the second difference transmitting the sub-time；
Specifically, transmission time, the first transmission sub-time, the second transmission sub-time all obey identical letter
Number distribution, such as Poisson distribution.The application may determine that under a series of different transmission time, the first transmission
The sub-time and second transmits the probability density function of the difference of sub-time.Probability density function illustrates difference
And the corresponding relation between probit.
Step S410, substitute into each probability density function with described default time error scope, calculate the time
The probit that range of error is corresponding；
Specifically, in the present embodiment with time error scope for (x, y) as a example by, then with time error x and
Y transmits sub-time and the second difference transmitting the sub-time respectively as first, by each probability density letter
Number may determine that the probit that time error scope is corresponding.
Wherein, the probit calculated by different probability density functions is different.
Step S420, determine that calculated probit exceedes the probability density function of default expected probability
The corresponding transmission time, and therefrom choose the transmission time of maximum as transmission time threshold.
Specifically, the application user can preset the expected probability of the time error scope falling into setting,
And then based on multiple probits that previous step draws, choose the probability density function institute exceeding expected probability
The corresponding transmission time.And therefrom choose the transmission time of maximum as transmission time threshold.
It is understood that if the transmission time is less than transmission time threshold, then time error falls into setting
The expected probability of time error scope is greater than setting expected probability.
Poisson distribution, the transmission timestamp of correction time=reply data bag is obeyed with transmission time RTT
Illustrate as a example by+0.5RTT.
The application may determine that under a series of different transmission time RTT, first transmits sub-time t1 and second
Transmit the probability density function of the difference of sub-time t2.
See Fig. 3, when present application illustrates RTT=500ms, 1000ms, 2000ms, the probability of t1-t2
The curve that density function is corresponding.
Assuming that the time error scope of user preset is (-50ms, 50ms), and error falls into this time by mistake
The expected probability of difference scope is 70%.
Then by time error scope (-50ms, 50ms) is substituted into three probability density letters shown in Fig. 3
In number, can be calculated:
During RTT=500ms, the probit that (-50ms, 50ms) is corresponding is 71%；
During RTT=1000ms, the probit that (-50ms, 50ms) is corresponding is 50%；
During RTT=2000ms, the probit that (-50ms, 50ms) is corresponding is 35%.
It follows that when RTT=500ms, the probit that (-50ms, 50ms) is corresponding exceedes the setting phase
Hope probit, and relatively expected probit, when therefore, it can choose RTT=500ms as transmission
Between threshold value.Determine the transmission time less than 500ms time, according to target device feedback reply data bag send out
Send timestamp, and transmission time RTT, calculate correction time: the transmission timestamp of reply data bag adds
0.5RTT。
It follows that time error scope and error that the application sets based on user fall into this time error
The expected probability of scope determines transmission time threshold, and then utilizes this transmission time threshold to time synchronized mistake
The transmission time that journey determines screens.The application scheme is easy to user flexibility and is controlled the precision of time synchronized
Time-consuming with time synchronization process.
In order to verify the degree of accuracy of the application time synchronized, now illustrate with the scene of multi-person interactive film.
The server providing interactive movie content enters with server as standard time source, multiple synchronizers
Row time synchronized.The present embodiment includes desktop computer, notebook, Android mobile phone and Fructus Mali pumilae with synchronizer
Illustrate as a example by mobile phone.Wherein, aforementioned four synchronizer under different network environments (cable network,
Wireless network, mobile network), carry out time synchronized, a certain moment, service according to the scheme of the application
41 points 15 seconds 8,41 points 15 seconds when the time after each synchronizer time synchronized is also 16 when the device time is 16
8.Time between each synchronizer can be maintained at the synchronization accuracy within 0.1 second, in other words, error
Rank is ten milliseconds of ranks, and compared to the other error of hundreds of Millisecond of prior art, its precision obtains
It is greatly promoted.
The time synchronism apparatus provided the embodiment of the present application below is described, and the time described below is same
Step device can be mutually to should refer to above-described method for synchronizing time.
Seeing Fig. 5, Fig. 5 is a kind of time synchronism apparatus structural representation disclosed in the embodiment of the present application.
As it is shown in figure 5, this device includes:
Synchronization request transmitting element 51, for sending time synchronized request to target device；
Reply data bag receive unit 52, for receive described target device return comprise transmission timestamp
Reply data bag；
Described transmission timestamp is the time for carrying out time synchronized that described target device determines.
Optionally, sending timestamp can be the time that target device receives the request of described time synchronized, also
It can be the time obtained after target device time of receipt (T of R) synchronization request union.
It is understood that in order to reduce network time, the size of reply data bag can be reduced.Such as,
Transmission timestamp is placed on the header part of reply data bag, the main part of reply data bag is left a blank,
To reduce the transmission time of reply data bag.
The transmission time determines unit 53, is used for determining and asks to receive institute from sending out described time synchronized
State the transmission time that packet is spent；
Specifically, the time receiving described reply data bag and the time sending the request of described time synchronized
Difference is transmission time RTT.
Transmission time threshold determines unit 54, is used for according to the time error scope preset and falls into this time
The expected probability of range of error, determines transmission time threshold；
Threshold decision unit 55, is used for judging that whether the described transmission time is less than described transmission time threshold；
Determine unit 56 correction time, be used for when the judged result of described threshold decision unit 54 is for being,
According to described transmission time and the transmission timestamp of described reply data bag, correct described synchronizer time
Between, to be allowed to keep consistent with the time of described target device.
It is understood that the described transmission time includes that the request of described time synchronized is sent out from described synchronizer
Deliver to the first transmission sub-time that described target device spends, and described reply data bag sets from described target
Preparation delivers to the second transmission sub-time that described synchronizer spends.
It is understood that when the judged result of described threshold decision unit 55 is no, can trigger and hold
The described synchronization request transmitting element 51 of row.
Optionally, described transmission time threshold determines that unit may include that
Probability density function determines unit, for the function distribution obeyed according to the transmission time, determines not
With the under the transmission time first probability density function transmitting sub-time and the second difference transmitting the sub-time；
Probit computing unit, for substituting into each probability density function with described default time error scope,
Calculate the probit that time error scope is corresponding；
The transmission time chooses unit, for determining that calculated probit exceedes default expected probability
The transmission time corresponding to probability density function, and therefrom choose the transmission time of maximum as transmission
Time threshold.
Optionally, the time synchronism apparatus of the application can also include:
Time record unit, for recording the transmission timestamp of described time synchronized request；And, record
The reception timestamp of described packet；
Based on this, the described transmission time determines that unit may include that
First transmission time determined subelement, when the transmission of the described time synchronized request according to record
Between stamp and described reply data bag receive timestamp difference, determine the transmission time.
Optionally, the time synchronism apparatus of the application can also include:
Chronograph control unit, for, while sending time synchronized request to target device, starting meter
Time device, during initial start, timer reading is zero；Receiving the reply data bag that described target device returns
While, terminate described timer；
Based on this, the described transmission time determines that unit may include that
Second transmission time determined subelement, for the timing result according to the described timer after terminating,
Determine the transmission time.
Optionally, determine that unit may include that above-mentioned correction time
First correction time determined subelement, for by the described transmission time with set coefficient product, with
The transmission timestamp of described reply data bag is added, and addition result is defined as the time of described synchronizer.
Wherein, setting coefficient can be 0.5.
For the hardware configuration of above-mentioned synchronizer, see Fig. 6, Fig. 6 for the embodiment of the present application provide same
The hardware architecture diagram of step equipment.As shown in Figure 6, this synchronizer may include that
Processor 1, communication interface 2, memorizer 3, communication bus 4, and display screen 5；
Wherein processor 1, communication interface 2, memorizer 3 and display screen 5 complete phase by communication bus 4
Communication between Hu；
Optionally, communication interface 2 can be the interface of communication module, such as the interface of gsm module；
Processor 1, is used for performing program；
Memorizer 3, is used for depositing program；
Program can include that program code, described program code include the operational order of processor.
Processor 1 is probably a central processor CPU, or specific integrated circuit ASIC
(Application Specific Integrated Circuit), or be configured to implement the embodiment of the present application
One or more integrated circuits.
Memorizer 3 may comprise high-speed RAM memorizer, it is also possible to also includes nonvolatile memory
(non-volatile memory), for example, at least one disk memory.
Wherein, program can be specifically for:
Time synchronized request is sent to target device；
Receive the reply data bag comprising transmission timestamp that described target device returns；
Determine and ask to receive the transmission that described reply data bag is spent from sending out described time synchronized
Time；
According to default time error scope and the expected probability falling into this time error scope, determine transmission
Time threshold；
Judge that whether the described transmission time is less than described transmission time threshold；
If so, according to described transmission time and the transmission timestamp of described reply data bag, correct described same
The time of step equipment.
Finally, in addition it is also necessary to explanation, in this article, the relational terms of such as first and second or the like
It is used merely to separate an entity or operation with another entity or operating space, and not necessarily requires
Or imply relation or the order that there is any this reality between these entities or operation.And, art
Language " includes ", " comprising " or its any other variant are intended to comprising of nonexcludability, thus
Make to include that the process of a series of key element, method, article or equipment not only include those key elements, and
Also include other key elements being not expressly set out, or also include for this process, method, article or
The key element that person's equipment is intrinsic.In the case of there is no more restriction, by statement " including ... "
The key element limited, it is not excluded that also deposit in including the process of described key element, method, article or equipment
In other identical element.
In this specification, each embodiment uses the mode gone forward one by one to describe, and each embodiment stresses
Being the difference with other embodiments, between each embodiment, identical similar portion sees mutually.
Described above to the disclosed embodiments, makes professional and technical personnel in the field be capable of or uses
The application.Multiple amendment to these embodiments will be aobvious and easy for those skilled in the art
See, generic principles defined herein can in the case of without departing from spirit herein or scope,
Realize in other embodiments.Therefore, the application is not intended to be limited to the embodiments shown herein,
And it is to fit to the widest scope consistent with principles disclosed herein and features of novelty.
Claims (14)
1. a method for synchronizing time, it is characterised in that be applied to synchronizer, the method includes:
Time synchronized request is sent to target device；
Receive the reply data bag comprising transmission timestamp that described target device returns；
Determine and ask to receive the transmission that described reply data bag is spent from sending out described time synchronized
Time；
According to default time error scope and the expected probability falling into this time error scope, determine transmission
Time threshold；
Judge that whether the described transmission time is less than described transmission time threshold；
If so, according to described transmission time and the transmission timestamp of described reply data bag, correct described same
The time of step equipment.
Method the most according to claim 1, it is characterised in that when the described transmission time includes described
Between synchronization request from described synchronizer send to described target device spend first transmission the sub-time, and
Described reply data bag sends the second transmission period of the day from 11 p.m. to 1 a.m spent to described synchronizer from described target device
Between；
The time error scope that described basis is preset and the expected probability falling into this time error scope, determine
The step of transmission time threshold, including:
The function distribution obeyed according to the transmission time, determines the first transmission sub-time under the different transmission time
Probability density function with the second difference transmitting the sub-time；
Substitute into each probability density function with described default time error scope, calculate time error scope pair
The probit answered；
Determine that calculated probit exceedes the biography corresponding to the probability density function of default expected probability
The defeated time, and therefrom choose the transmission time of maximum as transmission time threshold.
Method the most according to claim 1, it is characterised in that also include:
Record the transmission timestamp of described time synchronized request；And,
Record the reception timestamp of described reply data bag；
Described determine ask to receive what described reply data bag was spent from sending out described time synchronized
The transmission time, including:
During the reception sending timestamp and described reply data bag that the described time synchronized according to record is asked
Between stamp difference, determine the transmission time.
Method the most according to claim 1, it is characterised in that also include:
While sending time synchronized request to target device, start timer, timing during initial start
Device reading is zero；
While receiving the reply data bag that described target device returns, terminate described timer；
Described determine ask to receive what described reply data bag was spent from sending out described time synchronized
The transmission time, including:
According to the timing result of the described timer after terminating, determine the transmission time.
Method the most according to claim 1, it is characterised in that also include:
When judging that the described transmission time is not less than described transmission time threshold, trigger described to target device
Send the operation of time synchronized request.
6. according to the method described in any one of claim 1-5, it is characterised in that described according to described biography
Defeated time and the transmission timestamp of described reply data bag, correct the time of described synchronizer, including:
By described transmission time and the product setting coefficient, with the transmission timestamp phase of described reply data bag
Adding, addition result is defined as the time of described synchronizer.
Method the most according to claim 6, it is characterised in that the described coefficient that sets is as 0.5.
8. a time synchronism apparatus, it is characterised in that be applied to synchronizer, this device includes:
Synchronization request transmitting element, for sending time synchronized request to target device；
Reply data bag receives unit, sends timestamp for receiving comprising of described target device return
Reply data bag；
The transmission time determines unit, is used for determining and asks to receive described from sending out described time synchronized
The transmission time that reply data bag is spent；
Transmission time threshold determines unit, is used for according to the time error scope preset and falls into this time by mistake
The expected probability of difference scope, determines transmission time threshold；
Threshold decision unit, is used for judging that whether the described transmission time is less than described transmission time threshold；
Correction time determines unit, is used for when the judged result of described threshold decision unit is for being, according to
Described transmission time and the transmission timestamp of described reply data bag, correct the time of described synchronizer.
Device the most according to claim 8, it is characterised in that when the described transmission time includes described
Between synchronization request from described synchronizer send to described target device spend first transmission the sub-time, and
Described reply data bag sends the second transmission period of the day from 11 p.m. to 1 a.m spent to described synchronizer from described target device
Between；
Described transmission time threshold determines that unit includes:
Probability density function determines unit, for the function distribution obeyed according to the transmission time, determines not
With the under the transmission time first probability density function transmitting sub-time and the second difference transmitting the sub-time；
Probit computing unit, for substituting into each probability density function with described default time error scope,
Calculate the probit that time error scope is corresponding；
The transmission time chooses unit, for determining that calculated probit exceedes default expected probability
The transmission time corresponding to probability density function, and therefrom choose the transmission time of maximum as transmission
Time threshold.
Device the most according to claim 8, it is characterised in that also include:
Time record unit, for recording the transmission timestamp of described time synchronized request；And, record
The reception timestamp of described reply data bag；
The described transmission time determines that unit includes:
First transmission time determined subelement, when the transmission of the described time synchronized request according to record
Between stamp and described reply data bag receive timestamp difference, determine the transmission time.
11. devices according to claim 8, it is characterised in that also include:
Chronograph control unit, for, while sending time synchronized request to target device, starting meter
Time device, during initial start, timer reading is zero；Receiving the reply data bag that described target device returns
While, terminate described timer；
The described transmission time determines that unit includes:
Second transmission time determined subelement, for the timing result according to the described timer after terminating,
Determine the transmission time.
12. devices according to claim 8, it is characterised in that at described threshold decision unit
When judged result is no, triggers and perform described synchronization request transmitting element.
13. devices described in-12 any one according to Claim 8, it is characterised in that described correction time
Determine unit, including:
First correction time determined subelement, for by the described transmission time with set coefficient product, with
The transmission timestamp of described reply data bag is added, and addition result is defined as the time of described synchronizer,
Wherein, the described coefficient that sets is as 0.5.
14. 1 kinds of clock synchronization systems, it is characterised in that include at least one synchronizer and at least one
Individual target device, the clock of described target device is standard time clock；
Described synchronizer is used for, and sends time synchronized request to described target device；Receive described target
What equipment returned comprises the reply data bag sending timestamp；Determine from sending out the request of described time synchronized
To receiving the transmission time that described packet is spent；According to default time error scope and fall into this
The expected probability of time error scope, determines transmission time threshold；Judge whether the described transmission time is less than
Described transmission time threshold；If so, according to described transmission time and the transmission time of described reply data bag
Stamp, corrects the time of described synchronizer；
Described target device is used for, when receiving the time synchronized request that described synchronizer sends, according to
Self current time determines transmission timestamp, returns to described synchronizer and comprises described transmission timestamp
Reply data bag.
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