WO2012149751A1 - Procédé et dispositif correspondant pour étalonner des classes d'horloge - Google Patents

Procédé et dispositif correspondant pour étalonner des classes d'horloge Download PDF

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Publication number
WO2012149751A1
WO2012149751A1 PCT/CN2011/079861 CN2011079861W WO2012149751A1 WO 2012149751 A1 WO2012149751 A1 WO 2012149751A1 CN 2011079861 W CN2011079861 W CN 2011079861W WO 2012149751 A1 WO2012149751 A1 WO 2012149751A1
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WO
WIPO (PCT)
Prior art keywords
time synchronization
synchronization device
clock
time
clockclass
Prior art date
Application number
PCT/CN2011/079861
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English (en)
Chinese (zh)
Inventor
孙雅茹
程鹏
Original Assignee
华为技术有限公司
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Publication date
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to CN201180001783.XA priority Critical patent/CN102388556B/zh
Priority to PCT/CN2011/079861 priority patent/WO2012149751A1/fr
Publication of WO2012149751A1 publication Critical patent/WO2012149751A1/fr

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Classifications

    • 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
    • H04J3/0641—Change of the master or reference, e.g. take-over or failure of the master
    • 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

Definitions

  • the present invention relates to the field of communications, and in particular, to a clock level grading method and related equipment. Background technique
  • Second level. 1 is a time synchronization scheme in a telecommunication application scenario. As shown in FIG. 1, after the time synchronization device 11, the bearer device 12, and the base station 13 enable PTP, the time of the primary reference time source 10 can pass through the time synchronization device 11 and the bearer. The device 12 transmits to the base station 13, so that it is not necessary to separately configure the primary reference time source at each base station, thereby reducing the network planning cost.
  • each clock device (including the time synchronization device, the bearer device, and the base station) defines its own clock attribute.
  • the network can be calculated based on the Best Master Clock (BMC).
  • BMC Best Master Clock
  • the clock class of the clock device is defined by the clock class clockclass parameter.
  • Table 1 shows the main clockclass parameter values and meanings defined by the 1588v2 protocol:
  • a clock device with a ClockClass parameter value of 7 does not meet the hold requirement and is degraded to an alternate A clock.
  • the clock quality change of the time synchronization device is reflected by the change of the ClockClass parameter value of the time synchronization device.
  • Table 2 is the current clock attribute of each clock device in Figure 1. (To facilitate the differentiation of the two time synchronization devices 11 in Figure 1, the time synchronization device 11 on the left side of Figure 1 will be described as BITS-A, which will be in Figure 1 The time synchronization device 11 on the right is described as BITS-B).
  • the number of the BITS-A is assumed to be smaller than the clockID of BITS-B, that is, a ⁇ b, and the time-scale type used by BITS-A and BITS-B is the PTP time stamp.
  • the time-scale type used by BITS-A and BITS-B is the PTP time stamp.
  • the value of the Clockclass parameter output by the BITS-A and the BITS-B to the bearer device 12 is 6, and the bearer device follows the BMC.
  • the algorithm calculates the clock source of the current network as BITS-A.
  • the bearer device calculates the clock source of the current network as BITS-A according to the BMC algorithm.
  • BITS-A to bearer device 12 The output of the Clockclass parameter is reduced to 7.
  • the value of the Clockclass parameter output from the BITS-B to the bearer device 12 is reduced to 7. Since the clockID value of the BITS-A is smaller than the clockID value of the BITS-B, the bearer device calculates the current BMC algorithm.
  • the clock source for the network is BITS-A.
  • the bearer device uses BITS-A as the clock source of the current network, and cannot track the BITS with higher clock precision.
  • the ClockClass grading method defined by the existing 1588v2 protocol has at least the following disadvantages: in the scenario where the priority of all time synchronization devices is the same, when the primary reference time source of all time synchronization devices is lost, Ensure that the downstream device of the time synchronization device can switch to the time synchronization device with higher clock precision.
  • the embodiment of the present invention provides a clock level grading method and related equipment, which are used to solve the problem that a downstream device of a time synchronization device cannot be switched to a time synchronization device with high clock precision in a part of the scene.
  • a clock level grading method including:
  • the time synchronization device determines whether the tracked primary reference time source is lost.
  • the time synchronization device stores a clock class clockclass B, and the clock class B is used to indicate the clock level when the time synchronization device loses the tracked primary reference time source and enters the hold mode.
  • B is determined by the local clock precision when entering the hold mode, and the higher the local clock accuracy is, the smaller B is;
  • the clockclass B is output to the downstream device of the time synchronization device.
  • a time synchronization device including:
  • a storage unit configured to store a clock class clockclass B, wherein the clock class B is used to indicate a clock level when the time synchronization device loses the tracking main reference time source and enters the hold mode, and the B is determined by the local clock precision when entering the hold mode. The higher the accuracy of the above local clock, the smaller B is;
  • a determining unit configured to determine whether the tracked primary reference time source is lost
  • An output unit configured to: when the determining unit determines that the tracked primary reference time source is lost, the time synchronization system includes:
  • the time synchronization device stores a clock class clockclass B, and the above clockclass B is used. And indicating a clock level when the time synchronization device loses the tracking main reference time source and enters the hold mode, wherein the B is determined by the local clock precision when entering the hold mode, and the higher the local clock accuracy is, the smaller B is;
  • the time synchronization device is configured to determine whether the tracked primary reference time source is lost. When it is determined that the tracked primary reference time source is lost, the clockclass B is output to the bearer device.
  • the time synchronization device when the time synchronization device loses the tracked primary reference time source, the time synchronization device outputs the clockclass B stored on the time synchronization device to the downstream device, and the time synchronization device enters and maintains.
  • the higher the accuracy of the local clock in the mode the smaller the value of the clockclass parameter output by the time synchronization device is, that is, the smaller the B is.
  • the downstream device can know the time of the main reference time source of the lost tracking according to the received clockclass parameter value. Synchronizing the current clock accuracy level of the device.
  • FIG. 1 is a schematic diagram of a network structure of a time synchronization scheme in a telecommunication application scenario
  • FIG. 2 is a schematic flowchart of an embodiment of a clock level grading method according to an embodiment of the present invention
  • FIG. 3 is a schematic flowchart of another embodiment of a clock level grading method according to the present invention. Schematic diagram of the network structure under the example;
  • FIG. 5 is a schematic structural diagram of an embodiment of a time synchronization device according to the present invention.
  • FIG. 6 is a schematic structural diagram of an embodiment of a time synchronization system according to the present invention. detailed description
  • Embodiments of the present invention provide a clock level grading method and related equipment.
  • the technical solutions in the embodiments of the present invention are clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention.
  • the embodiments are merely a part of the embodiments of the invention, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.
  • the clock level grading method in the embodiment of the present invention includes:
  • the time synchronization device determines whether the tracked primary reference time source is lost.
  • the time synchronization device stores a clock class B.
  • the clock class B is used to indicate the clock level when the time synchronization device loses the tracked primary reference time source and enters the hold mode, where the value of B enters the hold mode by the time synchronization device.
  • the local clock accuracy is determined, and the higher the local clock accuracy is, the smaller B is.
  • the time synchronization device When the time synchronization device is unable to receive the signal of the primary reference time source, it can be determined that the currently tracked primary reference time source has been lost.
  • the time synchronization device and the downstream device are connected through the 1588 interface, and when the time synchronization device determines that the tracked primary reference time source is lost, the time synchronization device outputs the notification message carrying the clock class B to the downstream device (That is, the announcement of the announcement message, in which the 1588v2 ten-party discussion defines the format of the announcement message, as shown in Table 3:
  • the grandmasterClockQuality parameter in the table indicates the clock quality, as seen in Table 4, the grandmasterClockQuality parameter contains 4 bytes, by the clockclass parameter, The clockaccuracy parameter and the offsetscaledlogvariance parameter are composed.
  • the B is output as the value of the clockclass parameter in the advertisement.
  • the time synchronization device is interfaced through a one pulse per second (TOP, Time of Day) interface, and the time synchronization device passes the second pulse indication signal in the TOD information.
  • TOP Time of Day
  • the primary reference time source may be a Beidou satellite positioning system, or Global Positioning System (GPS), or other positioning systems, are not limited here.
  • GPS Global Positioning System
  • the time synchronization device when the time synchronization device loses the tracked primary reference time source, the time synchronization device outputs the clockclass B stored on the time synchronization device to the downstream device, and the time synchronization device enters and maintains.
  • the higher the accuracy of the local clock in the mode the smaller the value of the clockclass parameter output by the time synchronization device is, that is, the smaller the B is.
  • the downstream device can know the time of the main reference time source of the lost tracking according to the received clockclass parameter value. Synchronizing the current clock accuracy level of the device.
  • the time synchronization devices are sequentially divided into a first-level time synchronization device, a second-level time synchronization device, and a three-level time synchronization device according to the level of the level.
  • the first-level time synchronization device is a time synchronization device that satisfies the following specifications: At least one cuckoo clock and one satellite timing receiver can be traced to a higher-level time-keeping benchmark (such as a country) through a dedicated comparison method. Timing center ;);
  • the secondary time synchronization device is a time synchronization device that meets the following specifications: at least one cuckoo clock and one satellite timing receiver, which supports time-tracking to a first-level time synchronization device by ground means, and supports ground frequency signal punctuality function, And can reliably trace back to the country's frequency synchronization network;
  • the three-level time synchronization device is a time synchronization device that satisfies the following specifications: at least one high-stability crystal oscillator and one satellite timing receiver are supported, and the time is traced to the second-level time synchronization device or the first-level time synchronization device by ground means, and the support is provided. Ground frequency signal punctuality and reliable traceability to the local frequency synchronization network.
  • Table 4 For the three levels of time synchronization devices, the values and meanings of the main clockclass parameters are defined in Table 4 as follows: Table 4
  • the first-level time synchronization device maintenance requirement refers to the frequency synchronization signal punctuality maintained by the cesium atomic clock or traced to the national reference clock (PRC);
  • the secondary time synchronization device maintenance requirement refers to the maintenance by the cesium atomic clock;
  • the three-stage time synchronization device retention requirement refers to the use of a high-stability crystal oscillator.
  • A, B 1 3 ⁇ 4 B 2 and B 3 in the table are all natural numbers, and the following conditions are met:
  • the values of A, B 1 3 ⁇ 4 B 2 and B 3 can be 6, 7, 8, and 52, respectively.
  • the values of A, B 1 3 ⁇ 4 B 2 and B 3 can be 13, 14, 15, and 53, respectively.
  • A, B 1 3 ⁇ 4 B 2 and B 3 may also be other values satisfying A ⁇ B 2 ⁇ B 3 , which are not limited herein.
  • another embodiment of a clock level grading method of the present invention includes:
  • the time synchronization device determines whether the primary reference time source of the tracking is lost.
  • the time synchronization device stores a clock class B.
  • the clock class B is used to indicate the clock level when the time synchronization device loses the tracked primary reference time source and enters the hold mode, where the value of B enters the hold mode by the time synchronization device.
  • Local clock accuracy is determined if the above local time If the clock accuracy meets the requirement of the first-level time synchronization device, then B is equal to B 1 ; if the local clock accuracy meets the requirement of the secondary time synchronization device, B is equal to B 2 ; if the above local clock accuracy meets the requirements of the third-level time synchronization device , then B is equal to B 3 .
  • step 302 When the time synchronization device can normally receive the signal of the primary reference time source, it can be determined that the currently tracked primary reference time source is not lost, and step 302 is performed. When the time synchronization device is unable to receive the signal of the primary reference time source, it may be determined that the currently tracked primary reference time source has been lost, and step 303 is performed.
  • Output clockclass A to the downstream device The implementation of the clockclass A output to the downstream device may be as described in step 202 of Figure 2, and details are not described herein.
  • the time synchronization device when the time synchronization device loses the tracked primary reference time source, the time synchronization device outputs the clockclass B stored on the time synchronization device to the downstream device, and the time synchronization device enters and maintains.
  • the higher the accuracy of the local clock in the mode the smaller the value of the clockclass parameter output by the time synchronization device is, that is, the smaller the B is.
  • the downstream device can know the time of the main reference time source of the lost tracking according to the received clockclass parameter value. Synchronizing the current clock accuracy level of the device.
  • a clock level grading method is described in a specific application scenario example. As shown in FIG. 4, the time synchronization system architecture diagram in the application scenario includes a time synchronization device 43 and a time synchronization device 44.
  • the time synchronization device 43 is a primary time synchronization device, which is held by the cesium atomic clock when entering the hold mode, which tracks the primary reference time source 41, and the time synchronization device 44 is a secondary time synchronization device, and uses the cesium atomic clock when entering the hold mode. Keep, it tracks the main reference time
  • the bearer device 45 is a downstream device of the time synchronization device 43 and the time synchronization device 44.
  • the values outside the parentheses are the clockclass parameter values defined in the scenario where the PTP time stamp is used.
  • the value in the brackets is the value of the clockclass parameter defined in the scene using the ARB time stamp.
  • a and b are numbers of 8 bytes in size, and a>b.
  • the local clock precision of the time synchronization device 43 satisfies the first-level time synchronization device retention requirement, and the Clockclass parameter value m outputted to the carrier device 45 is equal to 7, and the time synchronization device 44 is held by the cesium atomic clock when entering the hold mode.
  • the local clock accuracy of the synchronization device 44 meets the requirement of the secondary time synchronization device.
  • the value of the Clockclass parameter output to the bearer device 45 is equal to 7.
  • the bearer device 45 can calculate the clock source of the current network as the time synchronization device 43 according to the BMC algorithm.
  • the bearer device 45 can learn that the current clock precision of the time synchronization device 43 with the value of the transmitted Clockclass parameter is 7 and the time of the first time synchronization device is maintained, and the value of the Clockclass parameter sent is 8 Synchronous device 44 current clock accuracy meets secondary time synchronization Preparation keeping requirements.
  • the time synchronization device when the time synchronization device loses the tracked primary reference time source, according to the clock precision of the time synchronization device entering the hold mode, the corresponding clockclass parameter value is output to the downstream device.
  • the downstream device can learn the current clock precision level of the time synchronization device of the lost reference primary reference time source according to the received clockclass parameter value.
  • the clock precision parameter of the time synchronization device is smaller, and the clockclass parameter value that is output to the downstream device after losing the tracked primary reference time source is smaller.
  • the downstream device can be switched to a time synchronization device with high clock precision after being calculated by the BMC algorithm, thereby solving the problem that the downstream device cannot be switched to the time synchronization device with high clock precision in this scenario.
  • a time synchronization device according to an embodiment of the present invention is described below. Referring to FIG. 5, the time synchronization device 500 of the embodiment of the present invention includes:
  • the storage unit 501 is configured to store a clock level clockclass B, where the clockclass B is used to indicate the clock level when the time synchronization device 500 loses the tracking main reference time source and enters the hold mode, and the B is the local clock precision when entering the hold mode. It is decided that the higher the accuracy of the above local clock, the smaller B is.
  • the determining unit 502 is configured to determine whether the tracked primary reference time source is lost.
  • the output unit 503 is configured to: when the determination result of the determining unit 502 is negative, to the time synchronization device
  • the downstream device outputs clockclass B in the storage unit 501.
  • the time synchronization device 500 and its downstream device are connected through the 1588 interface, and the output unit 503 outputs the clock class B to the downstream device through the advertisement message (ie, the announce message).
  • the time synchronization device 500 is connected through the 1PPS+TOD interface, and the output unit 503 outputs clockclass B to the downstream device through the second pulse indication signal in the TOD information, wherein the clockclass parameter value and the second pulse indication signal - Corresponding, that is, different clockclass parameter values are indicated by different second pulse indication signals.
  • the storage unit 501 is further configured to store clockclass A, where clockclass A is used to indicate that the time synchronization device 500 does not lose the tracked primary reference time source, where A ⁇ B; the output unit 503 is also used to determine When unit 502 determines that the tracked primary reference time source is not lost, it outputs clockclass A to its downstream device.
  • time synchronization device 500 of the embodiment may be used as the time synchronization device in the foregoing method embodiment, and may be used to implement all the technical solutions in the foregoing method embodiments, and the functions of the respective function modules may be implemented according to the foregoing method.
  • the method in the example is specifically implemented.
  • the time synchronization device when the time synchronization device loses the tracked primary reference time source, the time synchronization device outputs the clockclass B stored on the time synchronization device to the downstream device, and the time synchronization device enters and maintains.
  • the higher the accuracy of the local clock in the mode the smaller the value of the clockclass parameter output by the time synchronization device is, that is, the smaller the B is.
  • the downstream device can know the time of the main reference time source of the lost tracking according to the received clockclass parameter value. Synchronizing the current clock accuracy level of the device.
  • the time synchronization system 600 in the embodiment of the present invention includes: Time synchronization device 601 and bearer device 602;
  • the clock synchronization device 601 stores a clock level clockclass B, where clockclass B is used to indicate the clock level when the time synchronization device 601 loses the tracking main reference time source and enters the hold mode, and B is the local clock precision when entering the hold mode. It is decided that the higher the accuracy of the above local clock, the smaller B is.
  • the time synchronization device 601 is configured to determine whether the tracked primary reference time source is lost. When it is determined that the tracked primary reference time source is lost, the clockclass B is output to the bearer device 602.
  • the time synchronization device 601 further stores a clockclass A, wherein the clockclass A is used to indicate that the time synchronization device 601 does not lose the tracked primary reference time source, where A ⁇ B; the time synchronization device 601 is also used. When it is determined that the tracked primary reference time source is not lost, the above clockclass A is output to its downstream device.
  • the bearer device 602 when the bearer device 602 can track the time synchronization device 601, the clockclass parameter value output by the bearer device 602 is consistent with the clockclass parameter value of the received time synchronization device 601, and the bearer device 602 cannot track the time normally.
  • the bearer device 602 When the device 601 is synchronized, the bearer device 602 outputs a default clockclass parameter value.
  • time synchronization device 601 of this embodiment may be used as the time synchronization device in the foregoing method embodiment, and may be used to implement all the technical solutions in the foregoing method embodiments, and the functions of the respective functional modules may be implemented according to the foregoing method.
  • the method in the example is specifically implemented.
  • the time synchronization device in the time synchronization system 600 outputs the clockclass B saved on the time synchronization device to the downstream device when the tracked primary reference time source is lost, and the time synchronization device
  • the downstream device can learn the main reference time source of the lost tracking according to the received clockclass parameter value.
  • Time synchronization device current clock accuracy level when all the time synchronization devices tracked by the downstream device have the same priority, the higher the clock accuracy of the time synchronization device, the missing the tracked primary reference
  • the value of the clockclass parameter that is output to the downstream device after the time source is smaller. Therefore, the downstream device can be switched to the time synchronization device with high clock precision after being calculated by the BMC algorithm, thereby solving the above problem.
  • Downstream device switches to time synchronization with higher clock accuracy Problems on the device.
  • the disclosed systems, devices, and methods may be implemented in other ways.
  • the device embodiments described above are merely illustrative.
  • the division of the unit is only a logical function division.
  • there may be another division manner for example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored, or not executed.
  • the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be electrical, mechanical or otherwise.
  • the components displayed by the unit may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solution of the embodiment.
  • each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.
  • the above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.
  • the integrated unit if implemented in the form of a software functional unit and sold or used as a standalone product, may be stored in a computer readable storage medium.
  • the technical solution of the present invention may contribute to the prior art or all or part of the technical solution may be embodied in the form of a software product stored in a storage medium.
  • a number of instructions are included to cause a computer device (which may be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention.
  • the foregoing storage medium includes: a U disk, a removable hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and the like, which can store program codes. .

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Abstract

L'invention porte sur un procédé et un dispositif correspondant pour étalonner des classes d'horloge. Le procédé d'étalonnage de classes d'horloge comprend les opérations suivantes : un dispositif de synchronisation temporelle détermine si une source de temps de référence principale suivie est perdue ou non, le dispositif de synchronisation temporelle ayant un B de classe d'horloge stocké dans celui-ci, le B de classe d'horloge étant utilisé pour indiquer la classe d'horloge lorsqu'un dispositif de synchronisation temporelle qui a perdu la source de temps de référence principale suivie passe en mode d'entretien, le B étant déterminé par la précision de l'horloge locale lors du passage en mode d'entretien, et plus la précision de l'horloge locale est élevée, plus le B est faible ; et délivrer le B de classe d'horloge à un dispositif en aval du dispositif de synchronisation temporelle lorsqu'il est déterminé que la source de temps de référence principale suivie est perdue. La solution technique décrite par la présente invention peut être utilisée pour résoudre le problème selon lequel un dispositif en aval d'un dispositif de synchronisation temporelle dans certains scénarios ne peut pas être commuté vers un dispositif de synchronisation temporelle avec une précision d'horloge relativement élevée.
PCT/CN2011/079861 2011-09-20 2011-09-20 Procédé et dispositif correspondant pour étalonner des classes d'horloge WO2012149751A1 (fr)

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"IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems.", TECHNICAL COMMITTEE ON SENSOR TECHNOLOGY (TC-9)., 24 July 2008 (2008-07-24) *

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