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WO2018161282A1 - Procédé et appareil de synchronisation d'horloge et système de réseau optique passif - Google Patents

Procédé et appareil de synchronisation d'horloge et système de réseau optique passif Download PDF

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Publication number
WO2018161282A1
WO2018161282A1 PCT/CN2017/075992 CN2017075992W WO2018161282A1 WO 2018161282 A1 WO2018161282 A1 WO 2018161282A1 CN 2017075992 W CN2017075992 W CN 2017075992W WO 2018161282 A1 WO2018161282 A1 WO 2018161282A1
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WIPO (PCT)
Prior art keywords
clock
onu
olt
data
source
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PCT/CN2017/075992
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English (en)
Chinese (zh)
Inventor
赵殿博
殷锦蓉
王苏
隋猛
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华为技术有限公司
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Priority to PCT/CN2017/075992 priority Critical patent/WO2018161282A1/fr
Publication of WO2018161282A1 publication Critical patent/WO2018161282A1/fr

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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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L7/00—Arrangements for synchronising receiver with transmitter

Definitions

  • the present disclosure relates to the field of optical network technologies, and in particular, to a method and device for clock synchronization and a passive optical network system.
  • Optical network technology is a point-to-multipoint optical fiber transmission and access technology. Generally, it can be connected by an optical line terminal (OLT), an optical network unit (ONU), an optical splitter, and the above.
  • the OLT is used to control and manage each ONU in the optical network.
  • the optical fiber is used to transmit data between the OLT and the ONU.
  • the ONU is used for data interaction with the OLT to provide network services for user equipment connected to the ONU.
  • an ONU or an OLT in order to drive data transmission, an ONU or an OLT generally has its own clock, but in order to make the data transmission process orderly, the clocks of the OLT and the ONU are usually synchronized.
  • the OLT In clock synchronization, in order to ensure the accuracy of the clock in the optical network, the OLT generally obtains a clock from a high-precision clock source.
  • the high-precision clock source can be Synchronization Ethernet (SyncE), Global Positioning System (Global). Positioning System (GPS) or single-board clock, etc.
  • the OLT takes the acquired clock as its own working clock, and continuously transmits downlink data to the ONU according to the working clock, so that the ONU determines the clock edge through the transition edge of the downlink data, thereby acquiring the OLT. Clock.
  • the ONU can use the clock of the OLT as a reference clock, and calibrate its own clock to the clock of the OLT through the phase locked loop to realize clock synchronization with the OLT.
  • the OLT side may not have a high-precision clock source, but a high-precision clock source exists on the ONU side.
  • the clock of the ONU is synchronized to the clock of the OLT. Because the accuracy of the OLT's clock is not guaranteed, the clock is unstable, which may cause the transmission process to be disordered.
  • embodiments of the present disclosure provide a method, an apparatus, and a passive optical network system for clock synchronization.
  • the technical solution is as follows:
  • the first aspect provides a clock synchronization method, which is applied to a first optical network unit ONU in a Passive Optical Network (PON), where the first ONU is an ONU configured with a clock source,
  • PON Passive Optical Network
  • the optical line terminal OLT is instructed to synchronize the second clock to the clock of the clock source, and the second clock refers to the clock of the OLT.
  • the first clock of the first ONU is synchronized to the clock of the clock source, thereby instructing the OLT to synchronize the second clock of the first ONU to the clock of the clock source, so that the clock source does not exist on the OLT side, but the ONU side
  • the clocks of the OLT and the ONU are synchronized to the clock of the clock source, ensuring the accuracy and stability of the clock in the optical network, and further ensuring the reliability of the transmission process.
  • the indicating that the optical line terminal OLT synchronizes the second clock to the clock of the clock source includes:
  • the phase difference is sent to the OLT.
  • the phase difference between the second clock and the clock of the clock source is obtained, and the phase difference is sent to the OLT, so that when the OLT receives the phase difference, the second clock can be synchronized to the clock source according to the phase difference.
  • the clock provides a clock that does not exist on the OLT side, but the clock of the OLT and the ONU is synchronized to the clock source of the clock source in the scenario where the clock source exists on the ONU side. This ensures the accuracy of the clock in the optical network. Stability further ensures the reliability of the transmission process.
  • the acquiring a phase difference between the second clock and the first clock includes:
  • the sending the phase difference to the OLT includes:
  • phase difference is sent to the OLT.
  • phase difference it may be determined whether the phase difference is a constant. If the phase difference is constant, it may be determined that the OLT has achieved clock synchronization with the first ONU, so there is no need to send the phase difference to the OLT, if The phase difference is not constant, indicating that the clock of the current OLT is not synchronized with the clock of the ONU, and the phase difference is sent to the OLT.
  • the phase difference is not constant, indicating that the clock of the current OLT is not synchronized with the clock of the ONU, and the phase difference is sent to the OLT.
  • the indicating that the optical line terminal OLT synchronizes the second clock to the clock of the clock source includes:
  • Synchronizing data is continuously transmitted to the OLT according to a clock of the clock source, where the synchronization data is used by the OLT to acquire a clock of the clock source.
  • the OLT continuously sends the synchronization data to the OLT according to the clock of the clock source, so that the OLT can synchronize the second clock of the clock to the clock source of the clock source according to the continuously transmitted synchronization data, and the clock is not present on the OLT side.
  • the clocks of the OLT and the ONU are synchronized to the clock source of the clock source. This ensures the accuracy and stability of the clock in the optical network and further ensures the reliability of the transmission process.
  • the continuously sending the synchronization data to the OLT according to the clock of the clock source includes:
  • Synchronizing data is continuously transmitted to the OLT through an out-of-band channel according to the clock of the clock source, where the wavelength corresponding to the out-of-band channel is the same as the uplink wavelength corresponding to the data channel used for transmitting the uplink data, but the out-of-band channel
  • the corresponding circuit domain spectrum is different from the circuit domain spectrum corresponding to the data channel.
  • a specific method for transmitting synchronization data is provided, and the synchronization data is sent to the OLT through an outband channel, so that uplink data and synchronization data are transmitted by using different transmission resources, thereby avoiding mutual interference between the synchronization data and the uplink data.
  • the continuously sending the synchronization data to the OLT according to the clock of the clock source includes:
  • Synchronous data is continuously transmitted to the OLT through additional wavelengths according to a clock of the clock source, the additional wavelength being different from the upstream wavelength.
  • a specific method for transmitting synchronization data is provided, and the synchronization data is sent to the OLT through an additional wavelength, so that the uplink data and the synchronization data are transmitted by using different transmission resources, thereby avoiding mutual interference between the synchronization data and the uplink data.
  • a method for clock synchronization for an optical line terminal OLT in a passive optical network PON, the method comprising:
  • the second clock is synchronized to the clock source of the clock source according to the instruction of the first optical line terminal ONU, the first ONU is an ONU configured with a clock source, and the second clock is a clock of the OLT;
  • Downstream data is continuously sent to the second ONU according to the clock of the clock source, where the second ONU is an ONU with no clock source configured.
  • the OLT and the ONU are implemented in the scenario that the clock source is not present on the OLT side and the clock source exists on the ONU side in the scenario that the clock source is synchronized to the clock source according to the instruction of the first ONU.
  • the clocks are synchronized to the clock source of the clock source, ensuring the accuracy and stability of the clock in the optical network, further ensuring the reliability of the transmission process.
  • the downlink data may be continuously sent to the second ONU according to the clock of the clock source, so that the second ONU synchronizes its own clock to the clock of the clock source according to the downlink data, thereby realizing the light.
  • the clock synchronization of the network system ensures the accuracy and stability of the clock of the entire system, making the transmission process more reliable.
  • the clock that synchronizes the second clock to the clock source according to the indication of the first optical line terminal ONU includes:
  • phase difference refers to a phase difference between the second clock and a clock of the clock source
  • the second clock is synchronized to a clock of the clock source according to the phase difference.
  • the second clock can be synchronized to the clock of the clock source according to the phase difference, and the clock is not present on the OLT side, but the ONU side is provided.
  • the clocks of the OLT and the ONU are synchronized to the clock source of the clock source. This ensures the accuracy and stability of the clock in the optical network and further ensures the reliability of the transmission process.
  • the clock that synchronizes the second clock to the clock source according to the indication of the first optical line terminal ONU includes:
  • the second clock can be synchronized to the clock of the clock source according to the continuously transmitted synchronization data, and the clock is not present on the OLT side, but the clock is present on the ONU side.
  • the clocks of the OLT and the ONU are synchronized to the clock source of the clock source to ensure the accuracy and stability of the clock in the optical network, which further ensures the reliability of the transmission process.
  • the receiving the synchronization data continuously sent by the first ONU includes:
  • the outband channel And receiving, by the outband channel, the synchronization data continuously sent by the first ONU, where the wavelength corresponding to the outband channel is the same as the uplink wavelength corresponding to the data channel used for transmitting the uplink data, but the circuit domain spectrum corresponding to the outband channel And The circuit domain corresponding to the data channel has a different spectrum.
  • a specific method for receiving synchronization data is provided, and the synchronization data is received through the outband channel, so that the uplink data and the synchronization data are received by using different transmission resources, thereby avoiding mutual interference between the synchronization data and the uplink data.
  • the receiving the synchronization data continuously sent by the first ONU includes:
  • the synchronization data continuously transmitted by the first ONU is received by an additional wavelength, the additional wavelength being different from the upstream wavelength.
  • a specific method for receiving synchronization data is provided, and the synchronization data is received through the additional wavelength, so that the uplink data and the synchronization data are received by using different transmission resources, thereby avoiding mutual interference between the synchronization data and the uplink data.
  • a device for clock synchronization comprising a method comprising at least one module for implementing clock synchronization provided by any of the possible implementations of the first aspect or the first aspect.
  • a device for clock synchronization comprising a method comprising at least one module for implementing clock synchronization provided by any of the possible implementations of the second aspect or the second aspect.
  • a passive optical network PON system comprising an optical line terminal OLT, a beam splitter and an optical network unit ONU, the system further comprising a clock synchronization device and a fourth aspect according to the third aspect A clock synchronization device as described in the aspect.
  • the clock source refers to a high-precision clock source, such as a SyncE, a GPS, or a single-board clock.
  • the phase difference is used to represent a difference portion between the second clock and the clock of the clock source, and the phase difference may be a phase difference between the clock of the second clock and the clock source, or may be a voltage value or a current value related to the phase difference. .
  • Synchronous data refers to continuous data with at least one edge, such as 0101...
  • the data channel refers to the channel for transmitting uplink data, and its corresponding upstream wavelength is generally 1310 nm.
  • FIG. 1 is a system block diagram of a passive optical network PON according to an embodiment of the present disclosure
  • FIG. 2 is a schematic structural diagram of a device for clock synchronization provided by an embodiment of the present disclosure
  • 3A is a flowchart of a method for clock synchronization provided by an embodiment of the present disclosure
  • FIG. 3B is a flowchart of a method for clock synchronization provided by an embodiment of the present disclosure
  • FIG. 4 is a flowchart of a method for clock synchronization provided by an embodiment of the present disclosure
  • FIG. 5 is a schematic diagram of a spectrum provided by an embodiment of the present disclosure.
  • FIG. 6 is a block diagram of a device for clock synchronization provided by an embodiment of the present disclosure.
  • FIG. 7 is a block diagram of a device for clock synchronization provided by an embodiment of the present disclosure.
  • FIG. 1 is a system block diagram of a passive optical network PON according to an embodiment of the present disclosure.
  • the system includes at least one OLT at least one splitter and a plurality of ONUs.
  • the OLT is connected to the ONU or the optical splitter through an optical fiber.
  • the OLT is provided with a network interface through which the public switched telephone network (Public Switched) Telephone Network, PSTN), Internet (Internet) or Community Antenna Television (CATV) connection.
  • PSTN Public Switched Telephone Network
  • Internet Internet
  • CATV Community Antenna Television
  • the OLT can receive data from the network interface and broadcast the data to the ONU through the optical fiber; or, the OLT receives the data of each ONU through the optical fiber, and sends the data to the PSTN, the Internet, or the CATV through the network interface.
  • the beam splitter is used to separate or concentrate optical signals.
  • One of the plurality of ONUs is an ONU (hereinafter referred to as a clock source) configured with a high-precision clock source.
  • the clock source is used to provide a high-precision clock for the ONU, and the remaining ONUs are ONUs that are not configured with a clock source.
  • Each ONU is provided with a network interface, so that the ONU is connected to the user equipment through the network interface, thereby transmitting data exchanged between the user and the network.
  • the ONU configured with the clock source can synchronize its own clock to the clock of the clock source, and instruct the OLT to synchronize its own clock to the clock of the clock source, thereby enabling the ONU and the OLT without the clock source to be configured.
  • clock synchronization it is also possible to synchronize its own clock to the clock of the clock source, thereby ensuring the accuracy and stability of the clock of the entire PON system.
  • FIG. 2 is a schematic structural diagram of a device for clock synchronization provided by an embodiment of the present disclosure.
  • the first ONU includes at least a system clock module, a clock input module, a phase detector, and a Media Access Control (MAC) layer.
  • the system clock module is configured to generate a clock of the first ONU itself, drive the first ONU data transmission, acquire a clock of the OLT, and input the clock of the OLT into the phase detector; the clock input module is used to input the phase to the phase detector.
  • MAC Media Access Control
  • the clock of the precision clock source is configured to compare the phase difference between the two according to the clock input by the clock input module and the system clock module, and package the phase difference as a phase difference message to the MAC layer;
  • the layer is configured to send data of the first ONU to the OLT, receive data sent by the OLT, and input the received data into the system clock module.
  • the OLT includes at least a message extraction module, a frequency synthesizer, and a system clock module MAC layer.
  • the packet extraction module is configured to extract the data carried in the packet according to the protocol adopted by the packet, and if the phase difference carried in the phase difference packet is extracted, the packet extraction module may further input the extracted phase difference into the frequency.
  • Synthesizer; frequency synthesizer is used to calibrate the output frequency according to the phase difference, and input the output frequency into the system clock module;
  • the system clock module is used to obtain the output frequency of the frequency synthesizer as its own clock, and drive the data transmission of the OLT; The data between the OLT and the ONU is transmitted.
  • the second ONU includes at least a system clock module and a MAC layer.
  • the MAC layer is configured to send data of the second ONU to the OLT, receive data sent by the OLT, and input the received data into the system clock module;
  • the system clock module is configured to generate a clock of the second ONU itself, and continuously send according to the OLT. Downstream data, synchronizing its own clock to the clock of the OLT.
  • any of the above devices may also include a switch to transmit data without conflict.
  • any of the above ONUs may further include an Ethernet interface and a SyncE, such that the ONU performs data interaction with the user equipment through the SyncE and the Ethernet interface.
  • FIG. 3A is a flowchart of a method for clock synchronization provided by an embodiment of the present disclosure.
  • the system can include a first ONU, an OLT, and at least one second ONU.
  • the first ONU refers to an ONU that is provided with a clock source, and second.
  • the ONU is a clock that is not configured with a clock source.
  • the embodiment may be: the first ONU synchronizes the clock of the clock source with the first clock of the first ONU, and instructs the OLT to synchronize its second clock to the clock of the clock source, so that the OLT
  • the second ONU can synchronize its own clock to the clock of the clock source according to the received downlink data, thereby ensuring the clock precision of the entire PON system. And stability.
  • FIG. 3B is a flowchart of a method for clock synchronization provided by an embodiment of the present disclosure. Referring to FIG. 3B, the embodiment can be applied to the PON system shown in FIG. 1, and specifically includes the following steps:
  • the first ONU synchronizes the first clock to a clock of a clock source, where the first clock refers to a clock of the first ONU.
  • the first ONU is an ONU configured with a clock source.
  • the first ONU tracks the clock of the clock source through the phase locked loop, thereby synchronizing the first clock to the clock of the clock source.
  • the first ONU acquires a second clock according to downlink data continuously sent by the OLT.
  • the second clock refers to the clock of the OLT.
  • the OLT can receive the downlink data continuously sent by the OLT, and the first ONU can identify the edge of the downlink data, for example, The downlink data is 01010, and the first ONU can recognize a transition edge of 0 to 1 or a transition edge of 1 to 0. Since the downlink data is driven by the second clock of the OLT, the first ONU can determine the identified edge of the transition as the clock edge of the second clock, thereby determining the clock oscillation law of the OLT, and acquiring the second clock of the OLT.
  • the first ONU acquires a phase difference between the second clock and the clock of the clock source.
  • the first ONU may acquire a phase difference between the clock of the second clock and the clock source according to the acquired second clock and the clock of the current clock source.
  • the embodiment of the present disclosure does not limit the process of acquiring the phase difference.
  • the first ONU compares the clock of the second clock and the clock source, and obtains the phase difference obtained by comparing the relatives.
  • the first ONU can input the acquired second clock and the clock of the clock source into the phase detector, and compare the phase difference between the clock of the second clock and the clock source through the phase detector.
  • the output of the general phase detector is a voltage value (or current value) related to the phase difference. Therefore, the “phase difference” acquired by the first ONU may also be a voltage value (or current value) related to the phase difference. ).
  • the first ONU sends the phase difference to the OLT.
  • the first ONU may uplink the phase difference to the OLT.
  • the first ONU can encapsulate the phase difference into a phase difference message, so that the phase difference is sent to the OLT in the form of a message, and the protocol used by the phase difference message is not limited to the optical network unit management control interface (Optical Network) Unit Management and Control Interface (OMCI) protocol.
  • Optical Network Optical Network Unit Management and Control Interface
  • the clocks of the first ONU and the OLT may also be synchronized, that is, the current clock of the first ONU is the same as the clock of the OLT, and then the phase difference between the clock of the second clock and the clock source is constant, and then The first ONU may also be in phase with the OLT, and the phase difference between the second clock and the clock of the clock source is zero.
  • the clock is the frequency
  • the oscillation law of the second clock is s in(f1*t+a)
  • the oscillation law of the clock of the clock source is s in(f2*t+b)
  • the second clock and the clock source The phase difference of the clock is t*(f1-f2)+(ab).
  • the first ONU may first determine whether the phase difference is constant; if the phase difference is constant, determine that the OLT has been associated with the first ONU. Clock synchronization is implemented; if the phase difference is not constant, the ONU sends the phase difference to the OLT.
  • the second clock is synchronized to the clock of the clock source according to the phase difference.
  • the OLT when the OLT receives the phase difference message sent by the first ONU, the phase difference message can be parsed according to the protocol adopted by the phase difference message, thereby obtaining the phase difference (the voltage value or current related to the phase difference). value). Further, the OLT may calibrate the second clock based on the phase difference, for example, calibrating the output frequency of the frequency synthesizer based on the phase difference, and making the output frequency coincide with the clock of the clock source, thereby acquiring the clock of the clock source as its own clock, and realizing The ONU's clock is synchronized.
  • the second clock if the second clock is smaller than the clock of the clock source and the phase difference is negative, the output frequency of the frequency synthesizer is increased compared to the second clock. If the second clock is greater than the clock of the clock source, the phase difference is With a positive value, the output frequency of the frequency synthesizer is reduced compared to the second clock, so that the output frequency tends to the clock of the clock source.
  • the embodiment of the present disclosure obtains a phase difference between the second clock and the clock of the clock source, and sends the phase difference to the OLT, so that when the OLT receives the phase difference, the second clock can be synchronized to the clock source according to the phase difference.
  • the clock provides a specific method of synchronizing the clocks of the OLT and the ONU to the clock source of the clock source in the scenario where the clock is not present on the OLT side, and the clock is accurate and stable in the optical network. Sexuality further ensures the reliability of the transmission process.
  • the OLT continuously sends downlink data to the second ONU according to the clock of the clock source.
  • the second ONU is an ONU that does not have a clock source
  • the downlink data refers to data when the OLT and the second ONU interact normally.
  • the transmission process is more reliable, and the OLT can continuously send downlink data to the second ONU according to the clock of the synchronized clock source, of course,
  • the OLT broadcasts the feature that the OLT continuously transmits downlink data to each ONU in the optical network.
  • the second ONU When receiving the downlink data continuously sent by the OLT, the second ONU synchronizes its own clock to the clock of the clock source according to the downlink data continuously sent by the OLT.
  • the second ONU When the second ONU receives the downlink data continuously sent by the OLT, the current clock of the OLT, that is, the clock of the clock source, may be acquired, and the acquisition process is the same as the process of acquiring the second clock by the first ONU. Furthermore, the second ONU can track the clock of the clock source through the phase locked loop, thereby synchronizing its own clock to the clock of the clock source.
  • the current clock of the OLT can also be obtained.
  • the first ONU can continue to steps 302 and 303 to perform the clock synchronization process again.
  • clock synchronization is performed every 125 microseconds, and the first ONU performs a relative comparison every 125 microseconds, so that the OLT can perform clock calibration every 125 microseconds.
  • FIG. 4 is a flowchart of a method for clock synchronization provided by an embodiment of the present disclosure. Referring to FIG. 4, the embodiment can be applied to the PON system shown in FIG. 1, and specifically includes the following steps:
  • the first ONU synchronizes the first clock to a clock of a clock source, where the first clock refers to a clock of the first ONU.
  • This step is the same as step 300 above.
  • the first ONU continuously sends synchronization data to the OLT according to the clock of the clock source, where the synchronization data is used by the OLT to acquire a clock of the clock source.
  • the first ONU and the OLT are the same as the ONU and the OLT in step 301.
  • the synchronization data is one channel of data sent by the first ONU to the OLT separately, which is different from the uplink data, and the synchronization data has at least one edge, that is, the synchronization data includes at least one set of adjacent 01 (or 10), so that The OLT acquires the clock of the clock source based on the edge of the transition in the synchronous data.
  • the synchronization data and the uplink data may use different transmission resources, such as the frequency of the circuit domain spectrum or the optical domain, and the corresponding specific transmission process. See the following two examples (1) and (2):
  • the first ONU continuously sends synchronization data to the OLT through the outband channel according to the clock of the clock source, and the wavelength corresponding to the outband channel is the same as the uplink wavelength corresponding to the data channel used for transmitting the uplink data, but the outband channel corresponds to Electricity
  • the path spectrum of the road domain is different from the circuit domain corresponding to the data channel.
  • FIG. 5 is a schematic diagram of a spectrum provided by an embodiment of the present disclosure. As shown in FIG. 5, the spectrum of the uplink data is 20M-2.5 GHz, and the spectrum of the synchronous data is 0-20M.
  • the spectrum of the uplink data and the spectrum of the synchronization data may partially overlap, or the spectrum of the uplink data and the spectrum of the synchronization data do not overlap at all.
  • low-frequency data can be obtained through low-pass filtering, or high-frequency data can be obtained through high-pass filtering.
  • the first ONU continuously transmits the synchronization data to the OLT through the extra wavelength according to the clock of the clock source, and the extra wavelength is different from the uplink wavelength.
  • the first ONU may transmit the synchronization data by using an optical signal of an additional wavelength, and transmit the uplink data by using the optical signal of the uplink wavelength.
  • the optical signals of the two wavelengths can be separated by the splitter, and the synchronous data or the uplink data is further recovered by the optical receiver.
  • the OLT receives the synchronous data continuously sent by the first ONU, synchronizes the second clock to the clock of the clock source according to the ONU synchronization data.
  • the process of synchronizing the clock by the OLT according to the synchronous data is the same as the process of synchronizing the clock with the second ONU in step 306.
  • the embodiment of the present disclosure continuously sends synchronization data to the OLT according to the clock of the clock source, so that the OLT can synchronize its second clock to the clock of the clock source according to the continuously transmitted synchronization data, thereby providing no clock on the OLT side.
  • the clocks of the OLT and the ONU are synchronized to the clock source of the clock source. This ensures the accuracy and stability of the clock in the optical network and further ensures the reliability of the transmission process.
  • the OLT continuously sends downlink data to the second ONU according to the clock of the clock source.
  • This step is the same as step 305.
  • the second ONU When receiving the downlink data continuously sent by the OLT, the second ONU synchronizes its own clock to the clock of the clock source according to the downlink data continuously sent by the OLT.
  • This step is the same as step 306.
  • FIG. 6 is a block diagram of a device for clock synchronization provided by an embodiment of the present disclosure.
  • the apparatus includes:
  • a synchronization module 601 configured to perform the process involved in step 300 above;
  • the indicating module 602 is configured to perform the process involved in the foregoing steps 301, 302 or 303.
  • the first clock of the first ONU is synchronized to the clock of the clock source, thereby instructing the OLT to synchronize the second clock of the first ONU to the clock of the clock source, so that the clock source does not exist on the OLT side, but the ONU side
  • the clocks of the OLT and the ONU are synchronized to the clock of the clock source, ensuring the accuracy and stability of the clock in the optical network, and further ensuring the reliability of the transmission process.
  • the synchronization module 601 is further configured to perform the process involved in step 300 above.
  • the indication module 602 is further configured to perform the process involved in step 401 above.
  • FIG. 7 is a block diagram of a device for clock synchronization provided by an embodiment of the present disclosure.
  • the device includes:
  • a synchronization module 701 configured to perform the process involved in step 304 above;
  • the sending module 702 is configured to perform the process involved in step 305 above.
  • the OLT and the ONU are implemented in the scenario that the clock source is not present on the OLT side and the clock source exists on the ONU side in the scenario that the clock source is synchronized to the clock source according to the instruction of the first ONU.
  • the clocks are synchronized to the clock source of the clock source, ensuring the accuracy and stability of the clock in the optical network, further ensuring the reliability of the transmission process.
  • the downlink data may be continuously sent to the second ONU according to the clock of the clock source, so that the second ONU synchronizes its own clock to the clock of the clock source according to the downlink data, thereby realizing the light.
  • the clock synchronization of the network system ensures the accuracy and stability of the clock of the entire system, making the transmission process more reliable.
  • the synchronization module 701 is further configured to perform the process involved in step 402 above.
  • the sending module 702 is further configured to perform the process involved in step 403 above.
  • the device for clock synchronization provided in the above embodiment is only illustrated by the division of each functional device. In actual applications, the function distribution may be completed by different functional devices as needed. The internal structure of the device that synchronizes the clock is divided into different functional devices to perform all or part of the functions described above.
  • the method for the clock synchronization provided by the foregoing embodiment is the same as the method for the clock synchronization. The specific implementation process is described in detail in the method embodiment, and details are not described herein again.

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  • Optical Communication System (AREA)

Abstract

La présente invention concerne un procédé et un appareil de synchronisation d'horloge et un système de réseau optique passif, se rapportant au domaine technique des réseaux optiques. Le procédé est applicable à une première unité de réseau optique (ONU) dans un réseau optique passif (PON), la première ONU étant une ONU configurée avec une source d'horloge. Le procédé consiste à : synchroniser une première horloge avec une horloge d'une source d'horloge, la première horloge se référant à une horloge de la première ONU ; et ordonner à un terminal de ligne optique (OLT) de synchroniser une seconde horloge avec l'horloge de la source d'horloge, la seconde horloge se référant à une horloge de l'OLT. Dans la présente invention, la première horloge de la première ONU est synchronisée avec l'horloge de la source d'horloge, et en outre l'OLT reçoit l'instruction de synchroniser sa propre seconde horloge avec l'horloge de la source d'horloge, réalisant la synchronisation des horloges à la fois de l'OLT et de l'ONU avec l'horloge de la source d'horloge dans un scénario dans lequel aucune source d'horloge n'existe sur le côté OLT mais qu'une source d'horloge existe sur le côté ONU, ce qui permet d'assurer la précision et la stabilité d'une horloge dans un réseau optique, et d'assurer en outre la fiabilité d'un processus de transmission.
PCT/CN2017/075992 2017-03-08 2017-03-08 Procédé et appareil de synchronisation d'horloge et système de réseau optique passif WO2018161282A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030039272A1 (en) * 2001-03-20 2003-02-27 Thaddeus Dudziak System and method for synchronizing telecom-related clocks across an unsynchronized point-to-point network connection
CN101330374A (zh) * 2007-06-18 2008-12-24 大唐移动通信设备有限公司 传输网中的时钟同步方法、系统和从时钟侧实体
CN101860430A (zh) * 2010-06-24 2010-10-13 中兴通讯股份有限公司 一种实现光网络单元切换时钟源的装置及方法
CN102136900A (zh) * 2010-01-22 2011-07-27 华为技术有限公司 无源光网络的时间同步方法、装置及系统
CN104284258A (zh) * 2013-07-12 2015-01-14 上海贝尔股份有限公司 在pon中配置onu作为ieee1588主时钟的方法和装置

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030039272A1 (en) * 2001-03-20 2003-02-27 Thaddeus Dudziak System and method for synchronizing telecom-related clocks across an unsynchronized point-to-point network connection
CN101330374A (zh) * 2007-06-18 2008-12-24 大唐移动通信设备有限公司 传输网中的时钟同步方法、系统和从时钟侧实体
CN102136900A (zh) * 2010-01-22 2011-07-27 华为技术有限公司 无源光网络的时间同步方法、装置及系统
CN101860430A (zh) * 2010-06-24 2010-10-13 中兴通讯股份有限公司 一种实现光网络单元切换时钟源的装置及方法
CN104284258A (zh) * 2013-07-12 2015-01-14 上海贝尔股份有限公司 在pon中配置onu作为ieee1588主时钟的方法和装置

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