Signal synchronization method and device

Abstract

The invention provides a signal synchronization method and device, and relates to the field of communication. The method and the device are used for reducing clock recovery time and improving bandwidth utilization efficiency of a communication system. The method comprises: a first network device receiving a first signal from a second network device, the first signal corresponding to a first connection between the first network device and the second network device; the first network device obtains first clock information according to the first signal; the first network device receives a second signal from a second network device, wherein the first signal corresponds to a second connection between the first network device and the second network device; the first network device obtains second clock information according to the second signal; the first network device compensates the second clock information according to the first clock information to obtain third clock information, and the third clock information is compensated clock information.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of communication technology, and in particular, to a method and device for signal synchronization. Background Art

[0002] In the data center switching system, the process of two network devices communicating is usually to switch the original optical link first, and then establish the optical link between the two optical network devices. Then the CDR clock recovery is performed on the electrical signal converted from the optical signal. Since the frequency and phase of different services before and after the switching are not synchronized during the switching process of the optical link, CDR clock recovery is required to ensure the stability of data transmission. After the clocks of the two communicating network devices are synchronized, the network device receiving the signal can normally process the received data, and data transmission can proceed normally.

[0003] For example, the passive optical network (PON) system is a time division multiplexing system. The core device of the PON system, the optical line terminal (OLT), can send downlink signals to multiple optical network units (ONUs) by broadcasting, and can also receive uplink signals sent by multiple ONUs by time division multiple access. When the OLT sends downlink signals and multiple ONUs send uplink signals, both the OLT and the multiple ONUs need to switch the optical link. In the process of switching the optical link of the PON system equipment, for example, after the OLT disconnects the connection with the first ONU and switches to the connection with the second ONU, the OLT needs to re-establish clock synchronization with the second ONU so that the service between the OLT and the second ONU can work normally. Therefore, the equipment at the receiving end needs to restore the received input signal to the original clock and data signal through the clock data recovery technology (CDR), so as to achieve clock synchronization and ensure the stability of data transmission.

[0004] The main time bottleneck of optical link switching lies in the switching time of optical signals and the CDR time. Therefore, reducing the CDR time is very important for improving the performance of communication systems. Summary of the invention

[0005] The embodiments of the present application provide a signal synchronization method and device, which can reduce the CDR clock recovery time and improve the bandwidth utilization efficiency of the communication system.

[0006] In a first aspect, an embodiment of the present application provides a method for signal synchronization, the method comprising: a first network device receives a first signal from a second network device, the first signal corresponding to a first connection between the first network device and the second network device; the first network device obtains first clock information based on the first signal; the first network device receives a second signal from the second network device, the first signal corresponding to a second connection between the first network device and the second network device; the first network device obtains second clock information based on the second signal; the first network device compensates the second clock information based on the first clock information to obtain third clock information, the third clock information being the compensated clock information.

[0007] In the present application, before the first network device performs CDR clock recovery, the first network device first performs clock compensation on the second clock information based on the first clock information, the first clock information being the clock information corresponding to the first connection between the first network device and the second network device. Clock compensation is performed on the second clock information in advance, thereby reducing the clock deviation between the second signal and the local clock of the first network device, so that the first network device can more quickly achieve clock synchronization between the local clock and the second signal, thereby reducing the time for the first network device to perform CDR clock recovery, reducing the time for the optical network device to perform optical link switching, and improving the performance of the communication system.

[0008] In a possible implementation, the first network device obtains the first clock information based on the first signal, including: the first network device determines the first clock information based on the first signal and the local clock; the first network device obtains the second clock information based on the second signal, including: the first network device determines the second clock information based on the second signal and the local clock.

[0009] In the present application, the first clock information is determined by the first network device based on the first signal and the local clock, and the second clock information is determined by the first network device based on the second signal and the local clock. It is not the first clock information and the second clock information received from other network devices. The method of obtaining the clock information is stable and rapid, does not involve other devices, and the solution is simple, direct and easy to implement.

[0010] In one possible implementation, the first clock information includes first frequency deviation information, the second clock information includes second frequency deviation information, and the first network device compensates for the second clock information based on the first clock information, including: the first network device compensates for the second frequency deviation information based on the first frequency deviation information.

[0011] In one possible implementation, the first clock information includes first phase deviation information, the second clock information includes second phase deviation information, and the first network device compensates for the second clock information based on the first clock information, including: the first network device compensates for the second phase deviation information based on the first phase deviation information.

[0012] In a possible implementation, after the first network device compensates the second clock information according to the first clock information to obtain the third clock information, the method further includes: the first network device receives a third signal from the second network device, the third signal corresponding to a third connection between the first network device and the second network device; the first network device obtains fourth clock information according to the third signal; and the first network device compensates for the fourth clock information according to the third clock information.

[0013] In this possible implementation, the first network device acquires the third clock information after compensation, and the third clock information is used for compensation in the next connection, that is, the third connection. Acquiring the third clock information instead of the first clock information for compensation can make clock recovery more accurate; on the other hand, acquiring the third clock information after compensation makes the acquired third clock information more accurate.

[0014] In one possible implementation, before the first network device receives the first signal from the second network device, the first network device is in a connected state with the third network device, and the above method also includes: the first network device receives a switching instruction; according to the instruction of the switching instruction, the first network device disconnects from the third network device and establishes a first connection with the second network device.

[0015] In the present application, the first network device can switch the connected network device according to the instruction of the switching instruction, and specifically provides a solution for establishing a first connection between the first network device and the second network device, thereby enhancing the feasibility of the present application.

[0016] In a possible implementation, the first network device is a passive optical network PON device.

[0017] In a possible implementation, the first network device is a master device of the second network device and the third network device, and the second network device and the third network device are slave devices of the first network device.

[0018] In the present application, the first network device is the master device of the second network device and the third network device. The first network device executes clock compensation related steps, reducing the participation of the second network device and the third network device as slave devices, reducing the interaction between devices, and making the solution simpler and easier to implement.

[0019] In a second aspect, an embodiment of the present application provides a first network device, which is a first passive optical network PON device. The first PON device is used to implement the method provided by any possible implementation of the first aspect. The first PON device includes: a receiving module, a clock data recovery CDR module, a proportional integral PI loop filter module, an accumulator, a digitally controlled oscillator DCO module, a phase-locked loop PLL module and a memory, wherein: the receiving module is used to receive a first signal and a second signal from a second PON device; the CDR module, the PI loop filter module, the accumulator and the DCO module are used to obtain first clock information according to the first signal; and are also used to obtain second clock information according to the second signal; and are also used to compensate the second clock information according to the first clock information to obtain third clock information; the PLL module is used to provide a local clock; and the memory is used to store the first clock information and the third clock information.

[0020] In one possible implementation, the Rx module is also used to receive a third signal from the second network device; the CDR module, the loop filter module, the accumulator and the DCO module are also used to obtain fourth clock information based on the third signal; the fourth clock information is compensated according to the third clock information to obtain fifth clock information, and the fifth clock information is the compensated clock information.

[0021] In a possible implementation, the first PON device further includes: a scheduler, configured to receive a switching instruction, where the switching instruction instructs the first PON device to disconnect a current connection with the third PON device and establish a connection with the second PON device.

[0022] In a third aspect, an embodiment of the present application provides a first network device, which includes: a first receiving module, used to receive a first signal from a second network device, the first signal corresponding to a first connection between the first network device and the second network device; a first acquisition module, used to obtain first clock information based on the first signal; a second receiving module, used to receive a second signal from the second network device, the second signal corresponding to a second connection between the first network device and the second network device; a second acquisition module, used to obtain second clock information based on the second signal; a first compensation module, used to compensate the second clock information based on the first clock information to obtain third clock information, the third clock information being the compensated clock information.

[0023] In a possible implementation, the first acquisition module is specifically used to determine the first clock information according to the first signal and the local clock; the second acquisition module is specifically used to determine the second clock information according to the second signal and the local clock.

[0024] In a possible implementation, the first clock information includes first frequency deviation information, the second clock information includes second frequency deviation information, and the compensation module is specifically used to compensate the second frequency deviation information according to the first frequency deviation information.

[0025] In a possible implementation, the first clock information includes first phase deviation information, the second clock information includes second phase deviation information, and the compensation module is specifically used to compensate the second phase deviation information according to the first phase deviation information.

[0026] In one possible implementation, the first network device also includes: a third receiving module, used to receive a third signal from the second network device, the third signal corresponding to a third connection between the first network device and the second network device; a third acquisition module, used to acquire fourth clock information based on the third signal; and a second compensation module, used to compensate for the fourth clock information based on the third clock information.

[0027] In one possible implementation, before the first network device receives the first signal from the second network device, the first network device is in a connected state with the third network device, and the method also includes: a fourth receiving module, used to receive a switching instruction; a switching module, used to disconnect the connection with the third network device and switch to establishing the first connection with the second network device according to the instruction of the switching instruction.

[0028] In a fourth aspect, an embodiment of the present application provides a first network device, comprising: a processor and a memory. The processor is coupled to the memory; the memory is used to store computer instructions, and the computer instructions are loaded and executed by the processor to enable the first network device to implement any one of the methods provided in the first aspect.

[0029] In a fifth aspect, an embodiment of the present application provides a chip, comprising: a processor and an interface circuit; the interface circuit is used to receive code instructions and transmit them to the processor; the processor is used to run the code instructions to execute any one of the methods provided in the first aspect.

[0030] In a sixth aspect, an embodiment of the present application provides a computer-readable storage medium, in which at least one computer program instruction is stored, and the computer program instruction is loaded and executed by a processor to implement any one of the methods provided in the first aspect above.

[0031] In a seventh aspect, an embodiment of the present application provides a computer program product, comprising computer execution instructions, which, when executed on a computer, enable the computer to execute any one of the methods provided in the first aspect.

[0032] The technical effects brought about by any implementation method in the second to fifth aspects can refer to the technical effects brought about by the corresponding implementation method in the first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of a scenario of an electrically interactive data center network;

[0034] Figure 2 A schematic diagram of a scenario of an optically interactive data center network;

[0035] Figure 3 A schematic diagram of a network architecture of a passive optical network PON system;

[0036] Figure 4 A schematic diagram of a transmission scenario of an uplink optical signal in a passive optical network PON system;

[0037] Figure 5 A schematic diagram of a network architecture of a signal synchronization method provided in an embodiment of the present application;

[0038] Figure 6 A schematic diagram of a network architecture of another signal synchronization method provided in an embodiment of the present application;

[0039] Figure 7 A schematic diagram of a flow chart of a signal synchronization method provided in an embodiment of the present application;

[0040] Figure 8 A flowchart of another signal synchronization method provided in an embodiment of the present application;

[0041] Fig. 9 A flowchart of another signal synchronization method provided in an embodiment of the present application;

[0042] Fig.10 A schematic diagram of the structure of a first optical network device provided in an embodiment of the present application;

[0043] Fig.11 A schematic diagram of the structure of another first optical network device provided in an embodiment of the present application;

[0044] Fig.12 A schematic diagram of the structure of an optical communication system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0045] In the description of this application, unless otherwise specified, " / " indicates that the objects associated with each other are in an "or" relationship, for example, A / B can represent A or B; "and / or" in this application is merely a description of the association relationship between associated objects, indicating that three relationships may exist, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural.

[0046] In the description of this application, unless otherwise specified, "plurality" means two or more than two. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0047] In addition, in order to clearly describe the technical solutions of the embodiments of the present application, in the embodiments of the present application, words such as "first" and "second" are used to distinguish the same items or similar items with substantially the same functions and effects. Those skilled in the art can understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit the difference.

[0048] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a concrete way for easy understanding.

[0049] It is understood that the "embodiment" mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present application. Therefore, the various embodiments in the entire specification do not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It is understood that in various embodiments of the present application, the size of the sequence number of each process does not mean the order of execution, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

[0050] It can be understood that some optional features in the embodiments of the present application may be implemented independently in certain scenarios without relying on other features, such as the solution on which they are currently based, to solve corresponding technical problems and achieve corresponding effects, or may be combined with other features according to needs in certain scenarios. Accordingly, the devices provided in the embodiments of the present application may also realize these features or functions accordingly, which will not be elaborated here.

[0051] In this application, unless otherwise specified, the same or similar parts between the various embodiments can refer to each other. In this application, if there is no special description or logical conflict between the various embodiments, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other, and different embodiments can be combined to form new embodiments according to their inherent logical relationships. The following implementation methods of this application do not constitute a limitation on the scope of protection of this application.

[0052] like Figure 1 As shown, the electrically interactive data center network is usually composed of a controller, a switch, and a large number of servers. Servers can communicate with each other and with external devices under the scheduling of the controller. With the development of technologies such as artificial intelligence, cloud computing, and the Internet of Things, the amount of data of various types has increased significantly, and the network traffic that needs to be processed by the data center network has also increased significantly. Therefore, it is difficult for existing electrically interactive communication technologies to meet the processing needs of large amounts of data. For example, the architecture of multi-level electrically exchanged communications makes it difficult for controllers to achieve rapid scheduling; in addition, the bandwidth of electrically exchanged communications is limited, and the power consumption of electrically interactive devices is relatively large.

[0053] like Figure 2 As shown in FIG, due to the shortcomings of electrical switching communication, current communications are more likely to use optical switching communication instead of electrical switching communication. Figure 2 As shown in the figure, the server clusters of optical switching communication can be connected through optical switches, which makes the networking flexible and the network architecture better. At the same time, optical switching communication also has the advantages of large bandwidth, low latency and low power consumption.

[0054] like Figure 3 As shown, the signal synchronization method provided in the embodiment of the present application can be applied to Figure 3The passive optical network (PON) system shown in the figure is a network system that uses optical fiber to transmit signals. Its characteristic is that it does not require the use of active devices such as power amplifiers, and can achieve data transmission through passive devices such as optical fibers and splitters. The PON system mainly includes the optical line terminal OLT, the optical network unit (ONU) and the optical distribution network (ODN). Among them, the optical line terminal (OLT) is the core device of the PON system, responsible for controlling and managing the entire network; ONU is the terminal device of the optical network, used to connect user terminal devices, such as Figure 3 ODN mainly consists of passive optical splitter (POS) and optical fiber, which are used to transmit optical signals, such as Figure 3 Passive optical splitter 1, passive optical splitter 2 and optical fiber.

[0055] Figure 4 As shown, in the PON system, for downstream signals, the OLT can assemble downstream service optical signals into frames and send them to multiple ONUs in a broadcast manner, that is, they are divided into multiple independent signals through an optical splitter, each of which contains frames sent to all specific ONUs. Each ONU only extracts the frames sent to itself, and then discards the frames corresponding to other ONUs. For upstream optical signals, multiple ONUs can share channels through time division multiple access (TDMA) to enable multiple ONUs to transmit upstream optical signals to one OLT. The OLT can allocate a corresponding transmission time slot to each ONU, and these transmission time slots are synchronized, so when the data packets are coupled into an optical fiber, there will be no conflict between the data packets of different ONUs. As shown Figure 4 As shown, data 1 from terminal device 1, data 2 from terminal device 2, and data 3 from terminal device 3 all send data information to the OLT, and data 1, data 2, and data 3 share a channel.

[0056] The importance of shortening the recovery time of clock data recovery technology (CDR) for the performance of the PON system can also be seen from the optical signal transmission of the PON system. The CDR circuit is a circuit inside the optical network equipment that can synchronize the clock of the transmitting and receiving optical module with the clock of the PON system. If the synchronization time of CDR recovery is too long, the sending and receiving clocks will be out of sync, thus affecting the bandwidth efficiency of the PON system. On the other hand, the PON system is a time division multiplexing system. Each ONU and OLT needs to transmit data in the same time slot, otherwise conflicts will occur and data will be lost. If the CDR synchronization time is long, the ONU and OLT will transmit data in different time slots, resulting in data conflicts and losses, thus affecting the bandwidth efficiency of the PON system.

[0057] In the data center optical switching system, the process of two optical network devices communicating is usually to switch the optical link to establish the optical link connection first, and then perform CDR clock recovery on the optical signal. Because the optical signal may have clock offset during the optical link switching process, CDR clock recovery is required to ensure the stability of data transmission. Data transmission can only proceed normally after the clocks of the two optical network devices in communication are synchronized.

[0058] The time bottleneck of the entire optical link switching process is mainly the switching time of the optical signal and the CDR clock recovery time. The switching of the optical signal includes the response time of the optical switch and the decoding time of the optical forward error correction code. The CDR clock recovery time depends on the performance of the CDR circuit. Therefore, reducing the CDR clock recovery time is very important to improve the performance of the data center optical switching system.

[0059] Clock Data Recovery (CDR) locking is a digital signal processing technology used to recover clock and data signals from interference such as distortion, noise and jitter, and to achieve clock synchronization, including frequency and phase synchronization. In data center optical switching systems, CDR locking can help the receiving end recover the input signal to the original clock and data signal, thereby achieving reliable data transmission. Optical switches usually deploy CDR locking technology on their ports to ensure stable transmission and reception of high-speed optical signals, thereby ensuring efficient operation of data centers. Therefore, CDR locking technology is very important for data center optical switching systems.

[0060] Based on this, an embodiment of the present application provides a method for signal synchronization, wherein a first network device receives a first signal from a second network device, the first signal corresponds to a first connection between the first network device and the second network device; the first network device obtains first clock information according to the first signal; the first network device receives a second signal from the second network device, the first signal corresponds to a second connection between the first network device and the second network device; the first network device obtains second clock information according to the second signal; the first network device compensates the second clock information according to the first clock information to obtain third clock information, and the third clock information is the compensated clock information. In this way, the first optical network device performs clock compensation on the second clock information before the first network device performs CDR clock recovery, thereby reducing the clock deviation between the second signal and the local clock of the first network device, so that the first network device can more quickly achieve clock synchronization between the local clock and the second signal, thereby reducing the time of CDR clock recovery, achieving accurate and stable data transmission and reception, and improving the performance of the optical network system such as bandwidth utilization.

[0061] The signal synchronization method provided in the embodiment of the present application can be applied to Figure 5 The optical network devices of the data center optical switching system shown in the figure are connected and communicated with each other through the scheduling of optical switches. Specifically, the data center optical switching system includes a first PON device, a second PON device and a third PON device. In the system, the first network device is the master device of the second network device and the third network device, and the second network device and the third network device are slave devices of the first network device. Any PON device includes: a receiving (receive x, Rx) module, a transmitting (transport x, Tx) module, a digitally controlled oscillator (digital-controlled oscillator, DCO) module, a phase locked loop (phase locked loop, PLL) module and a CDR module. Among them:

[0062] The receiving Rx module is used to receive signals from other PON devices and convert the signals into discrete digital signals Rx data. For example, the first PON device in the embodiment of the present application can receive signals from the second PON device.

[0063] The sending Tx module is used to output a signal Tx data. For example, the second PON device in the embodiment of the present application can send a signal to the first PON device.

[0064] The CDR module is used to extract the clock deviation between the local clock and the received signal from the received signal.

[0065] PLL module, used to provide local clock.

[0066] The DCO module is used to adjust the clock information according to the frequency adjustment information and the phase adjustment information. The adjusted clock information is used as the reference clock of the Rx module, thereby achieving clock synchronization between the local Rx module of the device and the received data.

[0067] When executing the time synchronization method provided in the embodiment of the present application, under the scheduling of the optical switch, the first PON device first disconnects from the third PON device and establishes a first connection with the second PON device. The receiving Rx module of the first PON device receives a first signal corresponding to the first connection, and the first signal comes from the Tx module of the second PON device; then the CDR module of the first PON device obtains the first clock information according to the first signal.

[0068] Under the scheduling of the optical switch, after the first PON device establishes a second connection with the second PON device, the receiving Rx module of the first PON device receives the second signal corresponding to the second connection, and the second signal comes from the Tx module of the second PON device; then the CDR module of the first PON device obtains the second clock information according to the second signal. After determining the first clock information and the second clock information, the first PON device compensates the second clock information according to the first clock information through the DCO module. Thereby reducing the clock deviation between the second signal and the local clock of the first network device, so that the first network device can more quickly achieve the clock synchronization of the local clock and the second signal, thereby reducing the CDR clock recovery time and improving the performance of the optical network system such as bandwidth utilization.

[0069] In addition, the signal synchronization method provided in the embodiment of the present application can also be applied to other devices, such as Figure 6 The optical line terminal OLT in the PON system shown in FIG. Figure 6 The modules included in the OLT shown are Figure 5 The functional modules and corresponding functions included in the PON device shown are similar and will not be described in detail here.

[0070] When executing the time synchronization method provided in the embodiment of the present application, under the scheduling of the ODN network, the optical line terminal OLT establishes a first connection with the optical network unit ONU. The receiving Rx module of the OLT receives a first signal corresponding to the first connection, and the first signal comes from the Tx module of the ONU; then the CDR module of the OLT obtains the first clock information according to the first signal.

[0071] Under the scheduling of the ODN network, after the OLT establishes a second connection with the ONU, the receiving Rx module of the OLT receives the second signal corresponding to the second connection, and the second signal comes from the Tx module of the ONU; then the CDR module of the OLT obtains the second clock information according to the second signal. After determining the first clock information and the second clock information, the OLT compensates the second clock information according to the first clock information through the DCO module. It can be understood that the signal synchronization method provided in the embodiment of the present application can also be applied to other devices that require CDR clock recovery, such as optical network devices (optical network terminal, ONT) or optical network units ONU, which are not specifically limited here.

[0072] The signal synchronization method provided in the embodiment of the present application can be applied to Figure 3 The equipment in the passive optical network PON system shown can also be applied to Figure 5 The equipment in the data center optical switching system shown in the figure can also be applied to equipment in other optical communication systems, which is not limited here.

[0073] It is understandable that in the embodiments of the present application, the execution subject may execute some or all of the steps in the embodiments of the present application, and these steps or operations are only examples. The embodiments of the present application may also execute other operations or variations of various operations. In addition, the various steps may be executed in different orders presented in the embodiments of the present application, and it is possible that not all operations in the embodiments of the present application need to be executed.

[0074] It should be noted that the message names between the devices or the names of the parameters in the messages in the following embodiments of the present application are only examples, and other names may be used in the specific implementation, and the embodiments of the present application do not specifically limit this.

[0075] like Figure 7 As shown, a signal synchronization method provided by an embodiment of the present application comprises the following steps:

[0076] 701. A first network device receives a first signal from a second network device.

[0077] The first network device receives a first signal from the second network device, the first signal corresponding to a first connection between the first network device and the second network device.

[0078] Specifically, after the second network device establishes a first connection with the first network device, the second network device sends a first signal to the first network device, where the first signal corresponds to the first connection between the first network device and the second network device.

[0079] Accordingly, the first network device receives the first signal from the second network device.

[0080] like Figure 8 As shown, in a possible implementation, the first network device may be a PON device, which may include a CDR module, a proportional integral (PI) loop filter module, an accumulator, a DCO module, a phase-locked loop PLL module, an Rx module, a digital signal processing module (DSP), a memory (storage module) and a scheduler, wherein the Rx module, the CDR module, the PI loop filter module, the accumulator and the DCO module constitute a CDR loop. The DSP module is used to process the data signal after clock synchronization. The memory is used to store clock information corresponding to other network devices. The scheduler is used to schedule the on-off switching of the optical link between the network device and other devices. Figure 8 The other modules of the first network device shown are Figure 5 The functional modules and corresponding functions included in the PON device shown are similar and will not be described in detail here.

[0081] Specifically, in step 701, the first network device may receive a first signal from the second network device through an Rx module.

[0082] In one possible implementation, Figure 8 As shown, the scheduler of the first network device receives a switching instruction, which instructs the first network device to switch the currently connected network device and establish a first connection with the second network device. After the first network device establishes the first connection with the second network device, the first network device receives a first signal from the second network device through the Rx module.

[0083] Specifically, Figure 5 As shown, the first network device is in a connected state with the third network device. After the scheduler of the first network device receives the optical switch path switching instruction, the first network device disconnects from the third network device according to the instruction of the switching instruction and establishes a first connection with the second network device. It can be understood that the first network device is the master device of the second network device and the third network device, and the second network device and the third network device are slave devices of the first network device.

[0084] In the embodiment of the present application, the scheduling in the optical switching system is to control the allocation and use of optical path resources according to the scheduling algorithm and rules to realize the switching and transmission between multiple optical signals. The scheduling methods in the optical switching system may include: static scheduling, dynamic scheduling and hybrid scheduling. Static scheduling means that the usage of all optical path resources is determined during system design, and the scheduling algorithm is fixed and cannot be adjusted. Dynamic scheduling refers to dynamically adjusting the allocation and use of optical path resources according to real-time requirements and network congestion. Hybrid scheduling refers to combining static scheduling and dynamic scheduling to allocate and use the entire optical path resources.

[0085] In the embodiment of the present application, clock offset may occur when the network device switches the optical link, so CDR clock recovery is required only after the network device switches the optical link. Therefore, it can be understood that this is only a possible scenario of switching the optical link, and other scenarios may also be possible, such as reconnection after the optical link is disconnected, which is not limited here.

[0086] 702. The first network device obtains first clock information according to the first signal.

[0087] The first network device obtains first clock information according to the first signal and the local clock, where the first clock information may include first frequency deviation information and / or first phase information.

[0088] Specifically, the first network device acquires first clock information, where the first clock information is clock information corresponding to a first connection between the first network device and the second network device, and the first clock information may include first frequency deviation information and / or first phase deviation information.

[0089] like Figure 8 As shown, the first network device can obtain the first frequency deviation information through the CDR module, and the node for obtaining the first frequency deviation information can be after the PI loop filter and before the accumulator. After the first network device obtains the first frequency deviation information, the first frequency deviation information can be stored in the memory.

[0090] The first network device may obtain the first phase deviation information through the CDR module, and the node for obtaining the first phase deviation information may be after the accumulator and before the DCO module. After obtaining the first phase deviation information, the first network device may store the first frequency deviation information in a memory.

[0091] As shown in Table 1, the memory of the first network device may store clock information corresponding to multiple network devices, and the clock information indicates the clock deviation when the first network device establishes a connection with multiple network devices for data transmission. The clock information may include frequency deviation information and phase deviation information. After acquiring the first clock information, the first network device stores the first clock information in the memory.

[0092] Table 1

[0093] Device 1 Device 2 … Equipment Frequency deviation information Poffset 1 Poffset 2 … Poffset n Phase deviation information Foffset 1 Foffset 2 … Foffset n

[0094] In this possible implementation, the first network device stores the clock information inside its own device. When the clock information is needed, it can be directly extracted from the internal memory instead of being obtained from the outside. The method of obtaining the clock information is stable and fast, does not involve other devices, and the solution is simple and direct.

[0095] 703. The first network device receives a second signal from the second network device.

[0096] The first network device receives a second signal from the second network device, the second signal corresponding to a second connection between the first network device and the second network device.

[0097] Specifically, after the second network device establishes the second connection with the first network device, the second network device sends a second signal to the first network device, where the second signal corresponds to the second connection between the first network device and the second network device.

[0098] Accordingly, if Figure 8 As shown, the first network device receives the second signal from the second network device through the Rx module.

[0099] It is understandable that after the first network device establishes the first connection with the second network device, the first connection with the second network device may be disconnected due to business reasons. When the first network device needs to communicate with the second network device, the first network device will establish a second connection with the second network device. Therefore, it can be understood that the second connection is the next connection of the first connection between the first network device and the second network device, and the first connection is the previous connection of the second connection between the first network device and the second network device.

[0100] 704. The first network device obtains second clock information according to the second signal.

[0101] The method for the first network device to obtain the second clock information according to the second signal may refer to the method for the first network device to obtain the first clock information in step 702, and will not be described in detail here.

[0102] 705. The first network device compensates the second clock information according to the first clock information to obtain third clock information.

[0103] The first network device compensates the second clock information according to the first clock information to obtain third clock information, where the third clock information is compensated clock information.

[0104] In the embodiment of the present application, the first clock information includes first frequency deviation information and first phase deviation information. The first network device can perform clock frequency deviation compensation according to the first frequency deviation information, and can also perform clock phase compensation according to the first phase deviation information.

[0105] Specifically, after the first network device obtains the first clock information, the first network device can perform clock frequency deviation compensation on the second clock information according to the first frequency deviation information in the first clock information. Figure 8 As shown, the first network device performs phase compensation on the second clock through a CDR loop composed of a CDR module, a PI loop filter module, an accumulator and a DCO module.

[0106] like Figure 8 As shown, the first network device can obtain a frequency deviation adjustment amount after processing the first frequency deviation information through a PI loop filter, and add the frequency deviation adjustment amount to the CDR loop, and the added node can be before the accumulator. Specifically, the first network device can add the first frequency deviation information to the CDR loop, and the accumulator adds the first frequency deviation information to the second frequency deviation information. Based on the local clock provided by the PLL module, the DCO module can be based on the compensated clock information.

[0107] Specifically, after the first network device obtains the first clock information, the first network device performs clock phase compensation on the second clock information according to the first phase deviation information in the first clock information. Figure 8 As shown, the first network device can determine the phase adjustment amount according to the first phase deviation information and the second phase deviation information, and then add the phase adjustment amount to the CDR loop, and the added node can be after the accumulator. In the embodiment of the present application, the first network device can perform both clock frequency deviation compensation and clock phase deviation compensation; in addition, it can also only perform clock frequency deviation compensation without clock phase deviation compensation; it can also only perform clock phase deviation compensation without clock frequency deviation compensation, which is not limited here.

[0108] In the present application embodiment, Figure 8 As shown, the CDR loop of the first network device may include a phase-locked loop PLL module and a digitally controlled oscillator DCO module; in addition, the CDR loop of the first network device may also include a phase-locked loop PLL module and a crystal oscillator module or a clock generator. Both CDR loops can implement the method provided in the embodiments of the present application, which is not specifically limited here.

[0109] like Fig. 9As shown, in the embodiment of the present application, the first network device can perform CDR clock recovery based on the clock information of the last communication with the second network device. For example, the CDR clock recovery can be performed with the clock information of the first communication during the second communication, and the CDR clock recovery can be performed with the clock information of the Kth communication during the K+1th communication. At the same time, when the first network device transmits data with a certain network device for the first time, since there is no clock information stored during the last communication with the network device, the first network device can perform CDR hard lock, that is, no clock compensation is performed.

[0110] In the embodiment of the present application, the second signal received by the first network device may include multiple data packets, and the first network device needs to perform clock compensation in sequence when processing the multiple data packets. For the multiple data packets, the first network device uses the first clock information for compensation. It is understandable that the multiple data included in the first signal can be in the form of data packets or other forms, such as data frames, which are not specifically limited here.

[0111] After the first network device compensates the second clock information according to the first clock information, the first network device can obtain third clock information, where the third clock information is compensated clock information and includes third frequency deviation information and third phase information.

[0112] like Figure 8 As shown, the first network device can obtain and store the third clock information in the memory. Specifically, the first network device obtains the third clock information and stores it in the memory. The method for the first network device to obtain the first clock information in step 702 can be referred to, and the details are not repeated here. In a possible implementation, since the optical link switching in the optical switching system is frequent, in order to reduce the storage space occupied by the clock information of the network device, after determining the third clock information, the first network device can overwrite the first clock information with the third clock information, and the first network device only retains the latest clock information corresponding to other network devices.

[0113] In this possible implementation, the first network device will acquire the third clock information after compensation, and the third clock information is used for clock compensation the next time the first network device is connected to other network devices. On the one hand, acquiring new clock information each time can make the next clock recovery more accurate; on the other hand, acquiring the third clock information after compensation makes the acquired third clock information more accurate.

[0114] In an embodiment of the present application, the second signal received by the first network device may include multiple data packets. When the first network device processes the multiple data packets, it is necessary to perform clock compensation in sequence. For the multiple data packets, the first network device uses the first clock information for compensation. However, each time the second clock information is clock compensated, the first network device stores the obtained third clock information in the memory. It is understandable that the multiple data included in the first signal can be in the form of data packets or in other forms, such as data frames, which are not specifically limited here.

[0115] 706. The first network device receives a third signal from the second network device.

[0116] The first network device receives a third signal from the second network device, the third signal corresponding to a third connection between the first network device and the second network device.

[0117] Specifically, after the second network device establishes the third connection with the first network device, the second network device sends a third signal to the first network device, where the third signal corresponds to the third connection between the first network device and the second network device.

[0118] Correspondingly, the first network device receives the third signal from the second network device through the Rx module.

[0119] It is understandable that after the first network device establishes the second connection with the second network device, the second connection with the second network device may be disconnected due to business reasons. When the first network device needs to communicate with the second network device, the first network device will establish a third connection with the second network device. Therefore, it can be understood that the third connection is the next connection of the second connection between the first network device and the second network device, and the second connection is the previous connection of the third connection between the first network device and the second network device.

[0120] 707. The first network device obtains fourth clock information according to the third signal.

[0121] In the embodiment of the present application, the first network device obtains the fourth clock information according to the third signal. Reference may be made to the method in step 702 for the first network device to obtain the first clock information, which will not be described in detail here.

[0122] 708. The first network device compensates for the fourth clock information according to the third clock information.

[0123] In the embodiment of the present application, the first network device compensates the fourth clock information according to the third clock information. Reference may be made to the method in step 705 for the first network device to perform clock compensation on the second clock information, which will not be described in detail here.

[0124] In an embodiment of the present application, before the first network device performs CDR clock recovery, the first network device first performs clock compensation on the second clock information based on the first clock information, the first clock information being the clock information corresponding to the first connection between the first network device and the second network device. Clock compensation is performed on the second clock information in advance, thereby reducing the clock deviation between the second signal and the local clock of the first network device, so that the first network device can more quickly achieve clock synchronization between the local clock and the second signal, thereby reducing the time for the first network device to perform CDR clock recovery, reducing the time for the optical network device to perform optical link switching, and improving the performance of the communication system.

[0125] The embodiment of the present application provides a first network device 1000. In the embodiment of the present application, the first network device 1000 can be divided into functional modules according to the above method example. For example, each functional module can be divided corresponding to each function, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present invention is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0126] In the case of dividing each functional module into corresponding functional modules, Fig.10 A possible structural diagram of the first network device 1000 involved in the above embodiment is shown. Fig.10 As shown, the first network device 1000 includes:

[0127] The fourth receiving module 1001 is used to receive a switching instruction; for example, in step 701, the first network device receives the switching instruction and establishes a connection with the second network device.

[0128] The switching module 1002 is used to disconnect the connection with the third network device according to the instruction of the switching instruction, and switch to establish a first connection with the second network device. For example, in step 701, the first network device receives the switching instruction and establishes a connection with the second network device.

[0129] The first receiving module 1003 is used to receive a first signal from the second network device, where the first signal corresponds to a first connection between the first network device and the second network device; for example, in step 702, the first network device receives the first signal from the second network device.

[0130] The first acquisition module 1004 is used to acquire first clock information according to the first signal; for example, in step 703, the first network device acquires the first clock information.

[0131] In a possible implementation, the first acquisition module 1004 is specifically used to: determine the first clock information according to the first signal and the local clock; for example, in step 703, the first network device acquires the first clock information.

[0132] The second receiving module 1005 is used to receive a second signal from the second network device, where the second signal corresponds to a second connection between the first network device and the second network device; for example, in step 704, the first network device receives the second signal from the second network device.

[0133] The second acquisition module 1006 is used to acquire second clock information according to the second signal; for example, in step 705, the first network device acquires the second clock information.

[0134] In a possible implementation, the second acquisition module 1006 is specifically configured to: determine the second clock information according to the second signal and the local clock. For example, in step 705, the first network device acquires the second clock information.

[0135] The first compensation module 1007 is used to compensate the second clock information according to the first clock information to obtain third clock information, where the third clock information is the compensated clock information. For example, in step 706, the first network device compensates the second clock information.

[0136] In a possible implementation, the first clock information includes first frequency deviation information, the second clock information includes second frequency deviation information, and the compensation module 1007 is specifically used to: compensate the second frequency deviation information according to the first frequency deviation information. For example, in step 706, the first network device compensates the second clock information.

[0137] In a possible implementation, the first clock information includes first phase deviation information, the second clock information includes second phase deviation information, and the compensation module 1007 is specifically used to: compensate the second phase deviation information according to the first phase deviation information. For example, in step 706, the first network device compensates the second clock information.

[0138] The third receiving module 1008 is used to receive a third signal from the second network device, where the third signal corresponds to a third connection between the first network device and the second network device; for example, in step 708, the first network device receives the third signal.

[0139] The third acquisition module 1009 is used to acquire fourth clock information according to the third signal; for example, in step 709, the first network device acquires the fourth clock information according to the third signal.

[0140] The second compensation module 1010 is used to compensate the fourth clock information according to the third clock information. For example, in step 710, the first network device compensates the fourth clock information according to the third clock information.

[0141] The various modules of the first network device may also be used to execute other actions in the method embodiment. All relevant contents of the steps involved in the method embodiment may be referred to the functional description of the corresponding functional modules and will not be repeated here.

[0142] Fig.11 It is a schematic diagram of the structure of a first network device provided in an embodiment of the present application. The first network device 1100 may include one or more central processing units (CPU) 1101 and a memory 1105. The memory 1105 stores one or more application programs or data.

[0143] The memory 1105 may be a volatile storage or a persistent storage. The program stored in the memory 1105 may include one or more modules, each of which may include a series of instruction operations in the first network device. Furthermore, the central processor 1101 may be configured to communicate with the memory 1105 and execute a series of instruction operations in the memory 1105 on the first network device 1100.

[0144] The central processor 1101 is used to execute the computer program in the memory 1105, so that the first network device 1100 is used to execute: the first network device receives a first signal from the second network device, the first signal corresponds to a first connection between the first network device and the second network device; the first network device obtains first clock information according to the first signal; the first network device receives a second signal from the second network device, the first signal corresponds to a second connection between the first network device and the second network device; the first network device obtains second clock information according to the second signal; the first network device compensates the second clock information according to the first clock information to obtain third clock information, and the third clock information is the compensated clock information. For specific implementation methods, please refer to Figure 7 Steps 701-710 in the illustrated embodiment are not described in detail here.

[0145] The first network device 1100 may also include one or more power supplies 1102, one or more wired or wireless network interfaces 1103, one or more input and output interfaces 1104, and / or one or more operating systems, such as Windows Server TM, Mac OS X TM, Unix TM, Linux TM, FreeBSD TM, etc.

[0146] The first network device 1100 may execute the aforementioned Figure 7 The operations performed by the first network device in the illustrated embodiment will not be described in detail here.

[0147] The embodiment of the present application provides a communication system 1200, the optical communication system 1200 includes a first network device 1201, a second network device 1202, a second network device 1203 and an optical switch 1204, wherein the first network device 1201 can execute the aforementioned Figure 7 The operations performed by the first network device in the embodiment shown in the figure may be performed by the second network device 1202. Figure 7 The operations performed by the second network device in the illustrated embodiment will not be described in detail here.

[0148] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using a software program, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loading and executing computer program instructions on a computer, all or part of the processes (or functions) of the embodiments of the present application are implemented. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. Computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, computer instructions can be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server, data center, etc. that contains one or more servers that can be integrated with a medium. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a solid state disk (SSD)), etc. In the embodiment of the present application, the computer may include the above device.

[0149] Although the present application is described herein in conjunction with various embodiments, in the process of implementing the claimed application, those skilled in the art may understand and implement other changes to the disclosed embodiments by viewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple situations. A single processor or other unit may implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

Claims

1. A signal synchronization method, characterized in that: The method comprises: A first network device receives a first signal from a second network device, the first signal corresponding to a first connection between the first network device and the second network device; The first network device acquires first clock information according to the first signal; The first network device receives a second signal from the second network device, the second signal corresponding to a second connection between the first network device and the second network device; The first network device acquires second clock information according to the second signal; The first network device compensates the second clock information according to the first clock information to obtain third clock information, where the third clock information is compensated clock information.

2. The method according to claim 1, characterized in that The first network device acquires first clock information according to the first signal, including: The first network device determines first clock information according to the first signal and a local clock; The first network device acquires second clock information according to the second signal, including: The first network device determines second clock information according to the second signal and a local clock.

3. The method according to claim 2, characterized in that The first clock information includes first frequency deviation information, the second clock information includes second frequency deviation information, and the first network device compensates the second clock information according to the first clock information, including: The first network device compensates the second frequency deviation information according to the first frequency deviation information.

4. The method according to claim 2 or 3, characterized in that: The first clock information includes first phase deviation information, the second clock information includes second phase deviation information, and the first network device compensates the second clock information according to the first clock information, including: The first network device compensates the second phase deviation information according to the first phase deviation information.

5. The method according to any one of claims 1 to 4, characterized in that: After the first network device compensates the second clock information according to the first clock information to obtain third clock information, the method further includes: The first network device receives a third signal from the second network device, the third signal corresponding to a third connection between the first network device and the second network device; The first network device acquires fourth clock information according to the third signal; The first network device compensates the fourth clock information according to the third clock information.

6. The method according to any one of claims 1 to 5, characterized in that: Before the first network device receives the first signal from the second network device, the first network device is in a connected state with the third network device, and the method further includes: The first network device receives a switching instruction; According to the instruction of the switching instruction, the first network device disconnects from the third network device and establishes the first connection with the second network device.

7. The method according to any one of claims 1 to 6, characterized in that: The first network device is a passive optical network PON device.

8. The method according to any one of claims 1 to 7, characterized in that: The first network device is a master device of the second network device and the third network device, and the second network device and the third network device are slave devices of the first network device.

9. A first passive optical network PON device, characterized in that: The first PON device is used to implement the method according to any one of claims 1 to 8, and the first PON device includes: a receiving module, a clock data recovery CDR module, a proportional integral PI loop filter module, an accumulator, a digital control oscillator DCO module, a phase-locked loop PLL module and a memory, wherein: The receiving module is used to receive a first signal and a second signal from a second PON device; The CDR module, the PI loop filter module, the accumulator and the DCO module are used to obtain first clock information according to the first signal; and to obtain second clock information according to the second signal; and to compensate the second clock information according to the first clock information to obtain third clock information; The PLL module is used to provide a local clock; The memory is used to store the first clock information and the third clock information.

10. The first PON device according to claim 9, characterized in that: The Rx module is further used to receive a third signal from the second network device; The CDR module, the loop filter module, the accumulator and the DCO module are further used to obtain fourth clock information according to the third signal; The fourth clock information is compensated according to the third clock information to obtain fifth clock information, and the fifth clock information is the compensated clock information.

11. The first PON device according to claim 10, characterized in that: The first PON device further includes: The scheduler is used to receive a switching instruction, where the switching instruction instructs the first PON device to disconnect the current connection with the third PON device and establish a connection with the second PON device.

12. A first network device, characterized in that: The first network device comprises: A first receiving module, configured to receive a first signal from a second network device, wherein the first signal corresponds to a first connection between the first network device and the second network device; A first acquisition module, used for acquiring first clock information according to the first signal; A second receiving module, configured to receive a second signal from the second network device, wherein the second signal corresponds to a second connection between the first network device and the second network device; A second acquisition module, used for acquiring second clock information according to the second signal; The first compensation module is used to compensate the second clock information according to the first clock information to obtain third clock information, where the third clock information is compensated clock information.

13. The first network device according to claim 12, characterized in that: The first acquisition module is specifically used to: determine first clock information according to the first signal and the local clock; The second acquisition module is specifically used to determine second clock information according to the second signal and the local clock.

14. The first network device according to claim 13, characterized in that: The first clock information includes first frequency deviation information, the second clock information includes second frequency deviation information, and the compensation module is specifically used for: The second frequency deviation information is compensated according to the first frequency deviation information.

15. The first network device according to claim 13 or 14, characterized in that: The first clock information includes first phase deviation information, the second clock information includes second phase deviation information, and the compensation module is specifically used for: The second phase deviation information is compensated according to the first phase deviation information.

16. The first network device according to any one of claims 12 to 15, characterized in that: The first network device also includes: A third receiving module, configured to receive a third signal from the second network device, wherein the third signal corresponds to a third connection between the first network device and the second network device; A third acquisition module, used for acquiring fourth clock information according to the third signal; The second compensation module is used to compensate the fourth clock information according to the third clock information.

17. The first network device according to any one of claims 12 to 16, characterized in that: Before the first network device receives the first signal from the second network device, the first network device is in a connected state with the third network device, and the method further includes: A fourth receiving module, used for receiving a switching instruction; A switching module is used to disconnect the connection with the third network device and switch to establishing the first connection with the second network device according to the instruction of the switching instruction.

18. A first network device, characterized in that: The first network device comprises a processor and a memory; the processor is coupled to the memory; the memory is used to store computer instructions, and the computer instructions are loaded and executed by the processor to enable the first network device to implement the method according to any one of claims 1-8.

19. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores at least one computer program instruction, and the computer program instruction is loaded and executed by a processor to implement the method according to any one of claims 1 to 8.

20. A computer program product, characterized in that The computer program product comprises computer-executable instructions. When the computer-executable instructions are executed on a computer, the computer is configured to implement the method according to any one of claims 1 to 8.

21. A communication system, characterized in that: The communication system comprises a first network device and a second network device, wherein the first network device is used to execute the method according to any one of claims 1 to 8, and the second network device is used to execute the method according to any one of claims 1 to 8.

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