WO2012071927A1 - Time synchronization information transmission method, system, and device - Google Patents

Abstract

The embodiments in the present invention disclose a time synchronization information transmission method, which includes: receiving first time synchronization information from an optical line terminal, wherein the first time synchronization information is the local time synchronization information of the optical line terminal and includes 1 Pulse per Second (1PPS) signals and Time of Day (ToD) signals; calculating the average period of multiple continuous 1PPS signals in the first time synchronization information, and adjusting the period of the next 1PPS signal or the period of the next group of 1PPS signals to be the average period; configuring the 1PPS signals after the period adjusted and the ToD signals to be second time synchronization information and sending the second time synchronization information to a user terminal device, so that the user terminal device can perform time synchronization processing with the information. The embodiments in the present invention also provide a time synchronization information transmission system and device.

Description

 Time synchronization information transmission method, system and device The present application claims priority to Chinese Patent Application No. 201010566546.5, entitled "Time Synchronization Information Transmission Method, System and Apparatus", filed on December 1, 2010, Chinese Patent Application No. 201010566546.5 The entire contents of which are incorporated herein by reference. Technical field

 The present invention relates generally to time synchronization techniques and, in particular, to a time synchronization information transmission method, system and apparatus that can be adapted for use in a passive optical network. Background technique

 Time synchronization usually refers to limiting the time offset between time synchronization information (year/month/day/hour/minute/second) and Universal Time Coordinate (UTC) of various communication devices or computer devices on the communication network. A synchronization process in a sufficiently small range (such as within 100 milliseconds). In general, computer time is used to record time synchronization information for events, such as email information, file creation and access time, database processing time, etc., so time synchronization is widely used on the Internet for computer applications. Time synchronization can also be applied to network charging and network maintenance methods. For example, due to the emergence of multiple operators and the existence of time-sharing rates of operators, time synchronization in network charging can reduce the inconsistency of inter-network charging. The loss of the bill; the alarms and logs of the network management system also need to accurately record the exact time of the event and alarm for fault and performance analysis.

On the other hand, with the "light into copper retreat" gradually become the mainstream access method of network technology, the application of optical access technology, especially Passive Optical Network (PON) technology, has been booming. A passive optical network is a point-to-multipoint (P2MP) network system, which mainly includes an optical line terminal (OLT) located at a central office, and multiple optical network units located at the user side. (Optical Network Unit, ONU) and an optical distribution network for distributing or multiplexing data signals between optical line terminals and optical network units. Based on bearer mobile services and multiple real-time For the requirements of service access, passive optical networks also need high-precision time synchronization performance. The time synchronization process of the existing passive optical network is mainly as follows: First, the time source device passes the global positioning system

The (Global Position System, GPS) module obtains UTC time synchronization information, and then transmits the time synchronization information to the optical line terminal of the central office of the passive optical network system, and the optical line terminal can

The time synchronization information is synchronized and externally outputted for use by users and devices at the back end, thereby time synchronization of the entire passive optical network system.

 It can be seen that in the existing passive optical network time synchronization process, the optical network unit completely follows the time synchronization information it receives from the optical line terminal and directly transmits the time synchronization information to the backend device. However, since the optical fiber on the transmission link may be suddenly bent or shaken due to an external force, it will cause a change in the line offset time between the optical line terminal and the optical network unit, thereby causing the output of the optical network unit. The time synchronization information has sudden jitter. The sudden jitter of the above time synchronization information will reduce the system's time synchronization performance. Summary of the invention

 In view of this, embodiments of the present invention provide a time synchronization information transmission method, system, and device that can solve the above problems.

 A time synchronization information transmission method, comprising: receiving first time synchronization information from an optical line terminal, the first time synchronization information being local time synchronization information of the optical line terminal, including a second pulse 1PPS signal and a day a time ToD signal; calculating an average period of the plurality of consecutive 1PPS signals in the first time synchronization information, and adjusting a period of the next or next set of 1PPS signals to the average period; and the ToD signal and the passing The periodically adjusted 1PPS signal is configured as second time synchronization information and sent to the user terminal device for time synchronization processing by the user terminal device.

A passive optical network system including an optical line terminal and a plurality of optical network units, wherein The optical line terminal is connected to the plurality of optical network units in a point-to-multipoint manner through an optical distribution network; the optical line terminal is configured to send first time synchronization information to the optical network unit, where the first time synchronization is performed. The information is local time synchronization information of the optical line terminal, and includes a second pulse 1PPS signal and a daily time ToD signal; the optical network unit is configured to receive the received first time synchronization information, and calculate a plurality of consecutive 1PPS signals. The average period, and the period of the next or next set of 1PPS signals is adjusted to the average period; the ToD signal and the periodically adjusted 1PPS signal are configured as second time synchronization information and sent to the user terminal device, For the user terminal device to perform time synchronization processing.

 A time synchronization information transmission device, comprising: a receiving module, configured to receive first time synchronization information from a higher-level time synchronization device, where the first time synchronization information is local time synchronization of the upper-level time synchronization device Information, comprising a second pulse 1PPS signal and a time-to-day ToD signal; a time synchronization processing module, configured to calculate an average period of the plurality of consecutive 1PPS signals in the first time synchronization information, and to send the next or next set of 1PPS signals The period is adjusted to the average period, and the ToD signal and the periodically adjusted 1PPS signal are configured as second time synchronization information; and the sending module is configured to send the second time synchronization information to the next level. The time synchronization device is configured to perform time synchronization processing on the next-stage time synchronization device.

 A time synchronization information transmission method, comprising: receiving first time synchronization information from a higher-level time synchronization device, where the first time synchronization information is local time synchronization information of the upper-level time synchronization device, including a second pulse 1PPS signal and a daily time ToD signal; calculating an average period of the plurality of consecutive 1PPS signals in the first time synchronization information, and adjusting a period of the next or next set of 1PPS signals to the average period; The ToD signal and the periodically adjusted 1PPS signal are configured as second time synchronization information and sent to the next-stage time synchronization device for time synchronization processing by the next-stage time synchronization device.

Compared with the prior art, the time synchronization information transmission method, system and device provided by the embodiments of the present invention calculate the average period of N consecutive 1PPS signals and adjust the period of the next or next set of 1PPS signals to the Average period, after the above period adjustment, the time synchronization letter The sudden jitter that may occur during the transmission can be reduced to 1/N, which improves the time synchronization performance of the system. DRAWINGS

 FIG. 1 is a schematic structural diagram of a passive optical network system.

 FIG. 2 is a schematic structural diagram of an optical network unit according to an embodiment of the present invention.

 3 is a schematic structural view of a debounce unit of a time synchronization processing module clock of the optical network unit shown in FIG. 2.

 Fig. 4 is a schematic diagram showing the waveform of the debounce unit shown in Fig. 3 when the average is taken by the pipeline.

 Fig. 5 is a schematic diagram showing the waveform of the debounce unit shown in Fig. 3 when the weighted average value is used.

 FIG. 6 is a flowchart of a time synchronization transmission method according to an embodiment of the present invention.

 FIG. 7 is a flowchart of a time synchronization transmission method according to another embodiment of the present invention. detailed description

 The time synchronization information transmission method, system and device provided by the embodiments of the present invention are described in detail below with reference to specific embodiments.

 The time synchronization information transmission method provided by the embodiment of the present invention can be applied to various wired or wireless communication network systems, such as an optical access network system, which can reduce the debounce processing by receiving effective time synchronization information on the communication device. The time synchronization information may be jittery during transmission of the communication network system to improve high performance time synchronization between communication devices of the communication network system.

Please refer to FIG. 1 , which is a schematic structural diagram of a passive optical network system applicable to a time synchronization information transmission method according to an embodiment of the present invention. The passive optical network system 100 is a point-to-multipoint optical access network system including at least one optical line terminal 110, a plurality of optical network units 120, and an optical distribution network 130. The optical line terminal 110 is connected to the plurality of optical network units 120 in a point-to-multipoint manner through the optical distribution network 130. Wherein, from the optical line terminal 110 to the optical network The direction of the network unit 120 is defined as the downstream direction, and the direction from the optical network unit 120 to the optical line terminal 110 is the upstream direction.

 The passive optical network system 100 can be implemented without any active devices to implement the optical line

Passive optical devices (such as optical splitters) in the optical distribution network 130 are implemented. Moreover, the passive optical network system 100 may be an Asynchronous Transfer Mode Passive Optical Network (ATM PON) system or a Broadband Passive Optical Network (BPON) system defined by the ITU-T G.983 standard, ITU-T G.984 Standard defined Gigabit Passive Optical Network (GPON) system, Ethernet Passive Optical Network (EPON) as defined by the IEEE 802.3ah standard, or next-generation passive optical network (NGA PON, such as XGPON or 10G EPON). The entire contents of the various passive optical network systems defined by the above-mentioned standards are incorporated herein by reference.

 The optical line terminal 110 is usually located at a central location (for example, a central office, CO), which can uniformly manage the plurality of optical network units 120, and is in the optical network unit 120 and an upper layer network (not shown). Transfer data between. Specifically, the optical line terminal 110 can serve as a medium between the optical network unit 120 and the upper layer network, and forward data received from the upper layer network to the optical network unit 120, and The data received by the optical network unit 120 is forwarded to the upper layer network. It should be understood that the specific structural configuration of the optical line terminal 110 may vary depending on the specific type of the passive optical network 100. In an embodiment, the optical line terminal 110 may include a time synchronization processing module 111, which may be used to use time source time synchronization information provided by the time synchronization device (or a synchronization time source) as OLT time synchronization information (ie, OLT). Local time information), and the OLT synchronization time information is broadcast to the plurality of optical network units 120 for the optical network unit 120 to perform tracking and synchronization processing.

The optical network unit 120 can be distributedly disposed at a user-side location (such as a customer premises). Place The data is forwarded to the user, and data received from the user is forwarded to the optical line terminal 110. Similarly, the specific structural configuration of the optical network unit 120 may vary depending on the specific type of the passive optical network 100. In an embodiment, the optical network unit 120 may further include a time synchronization processing module 122, which may be configured to acquire OLT time synchronization information broadcast by the optical line terminal 110, and at least the OLT time synchronization information. Part of the content is subjected to debounce processing to reduce d, jitter that may occur during transmission of the OLT time synchronization information in the optical distribution network 130, and time synchronization information subjected to debounce processing as ONU time synchronization information (ie, ONU The local time information is tracked and synchronized, and further sent to the user terminal device of the back end. In addition, the structure of the optical network unit 120 is similar to that of an optical network terminal (ONT). Therefore, in the solution provided in this application, the optical network unit and the optical network terminal can be interchanged.

 The optical distribution network 130 can be a data distribution system that can include fiber optics, optical couplers, optical splitters, and/or other devices. In one embodiment, the optical fiber, optical coupler, optical splitter, and/or other device may be a passive optical device, in particular, the optical fiber, optical coupler, optical splitter, and/or other The device may be a device that distributes data signals between the optical line terminal 110 and the optical network unit 120 without the need for power support. In addition, in other embodiments, the optical distribution network 130 may further include one or more processing devices, such as an optical amplifier or a relay device. In the branching structure shown in FIG. 1, the light The distribution network 130 may specifically extend from the optical line terminal 110 to the plurality of optical network units 120, but may also be configured in any other point-to-multipoint configuration. An embodiment of the present invention is specifically described below with reference to FIG. Referring to FIG. 2, the optical network unit 120 includes a receiving module 121, a time synchronization processing module 122, and a sending module 123 that are sequentially connected.

The receiving module 121 can receive the downlink optical signal from the optical line terminal 110 through the optical distribution network 130, where the downlink optical signal can carry OLT time synchronization information. In an embodiment, the OLT time synchronization information may be the optical line terminal 110. Local time information, which may be time synchronization information obtained by the synchronization time source from the GPS system and provided to the optical line terminal 110. Optionally, the optical line terminal 110 may directly use the time synchronization information provided by the synchronization time source as the OLT time synchronization information, and provide the downlink optical signal to the optical network unit 120; or the light The line terminal 110 may also use the information obtained after performing debounce processing on the time synchronization information provided by the synchronization time source as the OLT time synchronization information.

 In a specific embodiment, the OLT time synchronization information may be transmitted in a time information format of 1 PPS+ToD, which includes a 1 PPS (1 Pulse per Second) signal and a ToD (Time of Day) signal. Wherein the 1PPS signal is a pulse signal having a frequency of 1 Hz, with a rising edge of the pulse as the start of 1 second; the ToD signal is a serial signal, after 1 millisecond of the rising edge of the 1PPS pulse signal The transmission begins and is transmitted within 500 milliseconds, which can be used to advertise the exact time of the rising edge of the 1PPS pulse signal, accurate to year/month/day/hour/minute/second.

 The time synchronization processing module 122 may acquire the OLT time synchronization information from the receiving module 121 and extract the 1PPS signal and the ToD signal therefrom, and perform the 1PPS signal extracted from the OLT time synchronization information. The dithering process is performed, and the ToD signal and the 1PPS signal after the de-jitter processing are used as ONU time synchronization information and supplied to the output unit 126. On the other hand, the time synchronization processing module 122 may also perform time synchronization processing according to the ONU time synchronization information to keep the optical network unit 120 and the optical line terminal 110 time synchronized. For convenience of description, the 1 PPS signal extracted by the OLT time synchronization information without debounce processing is recorded as a 1PPS-1 signal, and the jittered 1 PPS signal is recorded as a 1PPS-2 signal.

 The sending unit 123 may output the ONU time synchronization information (including the ToD signal and the 1PPS_2 signal) output by the time synchronization processing module 122 after the de-shake processing to the user terminal device at the back end for the The user terminal device at the end performs tracking and synchronization.

In an embodiment, please refer to FIG. 2 and FIG. 3 together, the time synchronization processing module 122 The time synchronization logic unit 124, the debounce unit 125, and the output unit 126 may be included. It should be understood that the time synchronization logic unit 124, the debounce unit 125, and the output unit 126 may be software implemented functional units or hardware and software. A functional unit that is implemented collaboratively.

 The synchronization logic unit 124 may acquire the OLT time synchronization information from the receiving module 121, and extract the 1PPS-1 signal and the ToD signal from the OLT time synchronization information. Further, the synchronization logic unit 124 may directly provide the ToD signal to the output unit 126, and provide the 1PPS-1 signal to the debounce unit 125 for debounce processing.

 As shown in FIG. 3, the debounce unit 125 may include a counter 301, a period memory 302, and an average calculator 303. In a specific embodiment, the debounce unit 125 may select a stable high frequency clock signal as its operating clock, where the high frequency clock signal may be a line clock or a downlink recovered by the optical network unit 120. The line clock phase locked clock. Preferably, the frequency of the high frequency clock is relatively high. Specifically, the higher the frequency of the high frequency clock, the more stable the 1PPS-2 signal obtained by the debounce processing by the debounce unit 125.

 Further, in an embodiment, the debounce module 125 can also reduce burstiness by using a pipeline to average.

Specifically, the counter 301 can simultaneously receive the 1PPS-1 signal and the high frequency clock extracted by the time synchronization logic unit 124 from the OLT time synchronization information, and use the rising edge of the 1PPS-1 signal. As a trigger condition, the high frequency clock is counted and the corresponding count value is obtained at a time interval (ie, within one second) between rising edges of two adjacent 1PPS-1 signals. The count value may represent the period T of the 1PPS-1 signal within this second. Moreover, the counter 301 can separately count the rising edges of any subsequent two adjacent 1PPS-1 signals, and after counting the times, the counter 301 can obtain the count value obtained by the one-time counting, Τ ₂ Τ _Ν . Where Ν is a preset integer value, such as Ν can be equal to 5.

The periodic memory 302 can record and store the count value, T ₂ Τ _得到 obtained by the counter 301 after the above counting process, for the average calculator 303 to read and perform the mean value. Calculation.

The average calculator 303 may read the count value obtained by the first to Nth counts from the periodic memory 302 after the counter 301 performs at least N counts, T ₂

Τ _Ν , and calculate the average value Ta of the count values, that is, 13 = ^ + 12 + ... + T _N ) / N.

 Further, in an embodiment, referring to FIG. 4, the debounce unit 125 may generate and output a corresponding 1PPS-2 signal according to the average value Ta calculated by the N count values, where the 1PPS— The period of the 2 signal corresponds to the average value Ta. When the rising edge of the N+1th 1PPS-1 signal arrives, the debounce unit 125 unit may generate the 1 PPS-2 signal generated according to the average value Ta of the 1st to Nth 1PPS-1 signals. As the output signal of the N+1th second. Moreover, the 1PPS-2 signal output by the debounce unit 125 at the Nth + 2nd second corresponds to the average value Tb of the 2nd to N+1 1PPS-1 signals, and the 1PPS-2 of the output of the Nth 3rd second The signal corresponds to the average value Tc of the 3rd to N+1 2PPS-1 signals, and so on. As shown in FIG. 4, a waveform diagram of the 1PPS-1 signal and the 1PPS-2 signal is exemplarily represented by taking N=5 as an example, and the debounce unit 125 is obtained when the 6th 1PPS-1 signal arrives. The 1PPS-2 signal corresponding to the period Ta is output, in the number.

 In the above embodiment, it is assumed that the jitter jitter t generated during the transmission of the first to N 1PPS-1 signals can be reduced to t/5, that is, the jitter of the output of the 1PPS-2 signal is only left. The original 1/5, to achieve the effect of reducing burst jitter and improving time synchronization performance. In an alternate embodiment, the debounce module 125 may also reduce burstiness jitter by means of weighted averaging.

Specifically, referring to FIG. 5, when the rising edge of the N+1th 1PPS-1 signal arrives, the unit of the debounce unit 125 may average the signal according to the 1st to Nth 1PPS-1 signals. The 1PPS-2 signal generated by the value Ta is used as the output signal of the N+1th to 2Nth second. By analogy, in Wherein, the average value Tb is a period corresponding to the signal of the Ν + 1 to 2 IPPS-1 signals

The average value calculated by T _N+1 and T _2N ; and in the 3N+1 to 4N seconds, the debounce unit 125 outputs a 1PPS-2 signal of the average value Tc, respectively, and the average value Tc is according to the The average value calculated from the periods T _2N+1 and T ₃₁ ^f corresponding to 2N + 1 to 3N IPPS-1 signals. As shown in FIG. 5, a waveform diagram of the IPPS-1 signal and the 1PPS-2 signal is exemplarily shown by taking N=5 as an example. When the 6th to 10th 1PPS-1 signals arrive (i.e., 6-10 seconds), the debounce unit 125 outputs a 1PPS-2 signal corresponding to the period Ta, respectively.

 Moreover, in the above alternative embodiment, in order to calculate an average period corresponding to the first to Nth IPPS-1 signals, the counter 301 may use a rising edge of the first 1PPS-1 signal as a trigger condition. Counting the high frequency clock at a time interval between a rising edge of the first 1PPS-1 signal and a rising edge of the (N+1)th 1PPS-1 signal (ie, within N seconds) The count value T corresponding to 'J' is obtained, and the count value T corresponds to the total period of the IPPS-1 signal within the N seconds. After the average value calculator 303 reads the count value Ta' from the periodic memory 302, it divides it by N and calculates an average period Ta corresponding to the N IPPS-1 signals, that is, Ta = T/N. For example, when N = 5, the average period Ta can be Ta = T/5. And an average period Tb corresponding to the (N+1)th to the 2ndth IPPS-1 signal, an average period Tc corresponding to the 2N+1th to 3Nth 1 PPS-1 signals, and any subsequent N1s The calculation method of the average period corresponding to the PPS-1 signal is consistent with the calculation method of the above average period Ta.

It can be seen that the above-mentioned alternative embodiment can also effectively reduce the jitter that may occur in the transmission of the time synchronization information, thereby improving the performance of the system time synchronization performance. Based on the optical network unit 120 provided in FIG. 2 to FIG. 3, the embodiment of the present invention further provides a method for transmitting time synchronization information. Please refer to FIG. 6, which is a flowchart of a method for transmitting time synchronization information according to an embodiment of the present invention. The time synchronization information transmission method can be implemented in an optical network unit of a passive optical network system to improve time synchronization performance of the passive optical network system. In an embodiment, the time synchronization information transmission method may include:

 Step S11: Receive OLT time synchronization information from the optical line terminal, where the OLT time synchronization information includes a 1PPS signal and a ToD signal.

 Specifically, the optical network unit may receive OLT time synchronization information transmitted from the optical line terminal and transmitted through the optical distribution network, where the OLT time synchronization information may include a 1PPS signal and a ToD signal, where the 1 PPS signal and the ToD signal may be A source of synchronized time is acquired from the GPS system and provided to the optical line terminal.

 Step S12: Adjust a period of the 1PPS signal by means of averaging the pipeline to perform debounce processing on the 1 PPS signal.

 In step S12, the optical network unit may calculate an average period of the first to Nth 1PPS signals, and adjust a period of the (N+1)th 1PPS signal to the average period, where N is a preset integer value. Similarly, after the Nth second (ie, after receiving the Nth 1PPS signal), for any subsequent received 1PPS signal, the optical network unit can adjust its period to the first N 1 PPS signals. The averaging period, thereby performing debounce processing on the 1 PPS signal.

 For convenience of description, the 1PPS signals before and after the debounce processing are respectively recorded as 1PPS-1 signal and 1PPS-2 signal.

 First, the optical network unit may use a rising edge of the 1PPS-1 signal as a trigger condition, and a time interval between rising edges of two adjacent 1 PPS-1 signals (ie, the duration of the 1 PPS-1 signal) Within the time (1 second), the preset high frequency clock is counted and the corresponding count value is obtained. In counting

After N times, the optical network unit may perform averaging processing on N number _{TT 2} Τ Ν count values obtained, average value ^{_{13 = 1 + 1 1 2 +}} ... ... + Τ Ν) / Ν. Further, at the N+1th second, the Ν+1 1PPS-1 signal arrives, and the optical network unit may generate a 1PPS-2 signal with a period average of Ta, as the The output signal of the N + 1 second, that is, the 1PPS-2 signal of the N+1th output. Similarly, the period of the 1st and 2nd outputs of the 1PPS-2 signal outputted at the Nth + 2nd second is the average value Tb of the 2nd to N+1 1PPS-1 signals, and so on, at the Kth In seconds (Κ>Ν), the period of the Kth 1 PPS-2 signal is output Τ _κ corresponds to the Κ-Ν1 PPS-1 The signal to the K1th signal has a total of N 1PPS-1 signal period averages, that is, Τκ=(Τκ-Ν+Τ _Κ -(Ν-ΐ)+... +Τ _Κ-1 )/Ν.

 Step S13: The ToD signal and the despreading 1PPS signal are sent as ONU time synchronization information to the user terminal device at the back end.

 And before the sending the ONU time synchronization information to the user equipment of the back end, the optical network unit may further perform time synchronization processing on the internal function module by using the ONU time synchronization information as local time synchronization information. On the other hand, it should be understood that in the first to the first

The NPPS-1 signal may be directly output without processing when N seconds, that is, the 1PPS-2 signal in the ONU time synchronization information outputted at the 1st to the Nth seconds and the time synchronization information received with the OLT The 1PPS-1 signal is consistent. Please refer to FIG. 7, which is a flowchart of a method for transmitting time synchronization information according to an embodiment of the present invention. The time synchronization information transmission method can also be applied to an optical network unit of a passive optical network system, which can include:

 Step S21: Receive OLT time synchronization information from the optical line terminal, where the OLT time synchronization information includes a 1PPS signal and a ToD signal.

 Step S22: Adjust a period of the 1PPS signal by using a weighted averaging method to perform debounce processing on the 1PPS signal.

 In step S22, the optical network unit may calculate an average period of the first to Nth 1PPS signals, and adjust a period of the (N+1)th to the 2Nth 1PPS signals to the average period, where N is a preset Integer value. That is, in step S22, the optical network unit may calculate the average period of each group of 1PPS signals by using N 1PPS signals as a group, and adjust the period of the latter group of 1PPS signals to the previous group of 1PPS. The average period of the signal. After the above adjustment, the period of the i-group 1PPS signal is the average period of the i-th group 1PPS signal, thereby performing de-jitter processing on the 1PPS signal.

For the convenience of description, the 1PPS signals before and after the debounce processing are also respectively recorded as 1PPS-1. Signal and IPPS-2 signal.

 First, in step S22, the average period of each group (N) of IPPS-1 signals can be calculated in the following two ways.

 The first mode: the optical network unit can count the preset high frequency clock within the duration of the N 1PPS-1 signals of the same group of 1PPS-1 signals and obtain the IPPS corresponding to the N seconds. The count value T of the total period of the 1 signal is averaged by dividing the count value T by N to obtain an average value Ta = T/N.

The second mode: the optical network unit can use the rising edge of the 1PPS-1 signal as a trigger condition, and the time interval between two rising edges of the 1PPS-1 signal in the same group of 1PPS-1 signals (ie, Between the durations of each 1PPS_1 signal, respectively, the preset high frequency clock is counted and the corresponding N count values, T ₂ Τ _{得到 are obtained} , and then the optical network unit can average the above count values. The treatment yields the average value Ta = (Ti + T ₂ + ... + Τ _Ν ) / Ν.

 Further, during the period from the N+1 second to the second leap second, the optical network unit may generate a 1PPS-2 signal having a period average Ta, as the (N+1)th to the The output signal of 2N seconds, that is, the 1PPS-2 signal of the N+1th to 2Nth outputs. That is, the optical network unit converts the IPPS-1 signal into the 1PPS-2 signal of the period Ta every time during the period from the N+1th to the 2nd second. Similarly, within a time period from 2N+1 seconds to 3N seconds, the optical network unit converts the signal into the N+1th to 2Nth IPPS every time it receives a 1PPS-1 signal. 1 signal of the average period Tb of the 1PPS-2 signal. By analogy, when receiving the i+1+1th to (i+1)N IPPS-1 signals belonging to the i+1th group IPPS-1 signal, each time a 1PPS-1 signal is received, it is converted into The period is the 1PPS-2 signal of the average period of the Nth 1 PPS-1 signal of the i-th group.

Step S23, the ToD signal and the 1 PPS signal subjected to the de-shake processing are sent to the user terminal device of the back end as ONU time synchronization information. It should be understood that the time synchronization information transmission method and apparatus provided by the embodiments of the present invention are not in a Limited to applications in passive optical network systems, which can be applied to other time synchronization systems. Specifically, the time synchronization information transmission device of the time synchronization system may be configured with a time synchronization processing module as shown in FIG. 2 and FIG. 3, and the time synchronization information transmission device may receive the first time from the upper-level time synchronization device. Time synchronization information, the first time synchronization information is local time synchronization information of the upper-level time synchronization device, and includes a second pulse 1PPS signal and a time-time ToD signal; and, the time synchronization information transmission device can pass the The time synchronization processing module calculates an average period of the plurality of consecutive 1PPS signals in the first time synchronization information, and adjusts a period of the next or next group of 1PPS signals to the average period; and, the time synchronization The information transmitting device may further configure the ToD signal and the periodically adjusted 1PPS signal as the second time synchronization information and send the information to the next-stage time synchronization device for time synchronization processing by the next-stage time synchronization device. In a specific embodiment, the processing procedure of the time synchronization information transmission device may refer to the description of the above embodiment. Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus a necessary hardware platform, and of course, can also be implemented entirely by hardware. Based on such understanding, all or part of the technical solution of the present invention contributing to the background art may be embodied in the form of a software product, which may be stored in a storage medium such as a ROM/RAM, a magnetic disk, an optical disk, or the like. A number of instructions are included to cause a computer device (which may be a personal computer, server, or network device, etc.) to perform the methods described in various embodiments of the present invention or portions of the embodiments.

 The above is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or within the technical scope of the present disclosure. Alternatives are intended to be covered by the scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

Claim

A time synchronization information transmission method, comprising:

 Receiving first time synchronization information from the optical line terminal, the first time synchronization information being local time synchronization information of the optical line terminal, including a second pulse 1PPS signal and a time time ToD signal;

 Calculating an average period of the plurality of consecutive 1PPS signals in the first time synchronization information, and adjusting a period of the next or next group of 1PPS signals to the average period;

 The ToD signal and the periodically adjusted 1PPS signal are configured as second time synchronization information and sent to the user terminal device for time synchronization processing by the user terminal device.

2. The method according to claim 1, wherein the calculating an average period of the plurality of consecutive 1PPS signals in the first time synchronization information comprises:

 Provide a pre-configured high frequency clock;

 Using the rising edge of the 1PPS signal of the first time synchronization information as a trigger condition, respectively counting the high frequency clock within the duration of each of the plurality of consecutive 1PPS signals, and obtaining more Corresponding cycle count values;

 The plurality of cycle count values are averaged to obtain an average period value of an average period of the plurality of consecutive 1PPS signals.

3. The method according to claim 1, wherein the calculating an average period of the plurality of consecutive 1PPS signals in the first time synchronization information comprises:

 Provide a pre-configured high frequency clock;

 Using the rising edge of the 1PPS signal of the first time synchronization information as a trigger condition, counting the high frequency clock within a duration of a plurality of consecutive 1PPS signals to obtain a total cycle count value;

Dividing the total period count value by the number of the plurality of consecutive 1PPS signals to obtain the The average period value of multiple consecutive 1PPS signals.

The method according to any one of claims 1 to 3, wherein the adjusting the period of the next 1PPS signal to the average period comprises:

 And adjusting a period of the Kth 1PPS signal in the first time synchronization information to an average period of the KNth 1PPS signal to the K-1th 1PPS signal, where K and Ν are integers greater than 2, and Κ is greater than Hey.

The method according to any one of claims 1 to 3, wherein the adjusting the period of the next set of 1PPS signals to the average period comprises:

 And dividing the 1PPS signals in the first time synchronization information into multiple groups, wherein each group includes Ν 1 PPS signals;

 The period of each of the 1PPS signals in the i-th group 1PPS signal in the first time synchronization information is adjusted to the average period of the N 1PPS signals of the i-1th group 1PPS signal, respectively.

A passive optical network system, comprising: an optical line terminal and a plurality of optical network units, wherein the optical line terminal is connected to the plurality of lights in a point-to-multipoint manner through an optical distribution network Network unit

 The optical line terminal is configured to send first time synchronization information to the optical network unit, where the first time synchronization information is local time synchronization information of the optical line terminal, and includes a second pulse 1PPS signal and a daily time ToD signal. ;

 The optical network unit is configured to receive the received first time synchronization information, calculate an average period of the plurality of consecutive 1PPS signals, and adjust a period of the next or next set of 1PPS signals to the average period; The ToD signal and the periodically adjusted 1PPS signal are configured as second time synchronization information and sent to the user terminal device for time synchronization processing by the user terminal device.

7. A time synchronization information transmission device, comprising:

a receiving module, configured to receive first time synchronization information from a higher-level time synchronization device, where The first time synchronization information is local time synchronization information of the upper-level time synchronization device, and includes a second pulse 1PPS signal and a time-time ToD signal;

 a time synchronization processing module, configured to calculate an average period of the plurality of consecutive 1PPS signals in the first time synchronization information, adjust a period of the next or next group of 1PPS signals to the average period, and use the ToD The signal and the periodically adjusted 1PPS signal are configured as second time synchronization information;

 And a sending module, configured to send the second time synchronization information to the next-stage time synchronization device, for the next-level time synchronization device to perform time synchronization processing.

8. The time synchronization information transmission device according to claim 7, wherein the time synchronization processing module comprises a time synchronization logic unit, a debounce unit, and an output unit;

 The time synchronization logic unit is configured to extract the acquired 1PPS signal and the ToD signal from the first time synchronization information, and provide the 1PPS signal to the debounce unit for debounce Processing, the ToD signal is directly provided to the output unit; the debounce unit is configured to receive a 1PPS signal provided by the time synchronization logic unit, and to the 1PPS signal according to an average period of the plurality of consecutive 1PPS signals The period is adjusted to perform debounce processing on the 1PPS signal;

 And an output unit, configured to configure the ToD signal provided by the time synchronization logic unit and the period-adjusted 1PPS signal provided by the debounce unit as second time synchronization information.

9. The time synchronization information transmitting apparatus according to claim 8, wherein said time synchronization processing module comprises

 a counter, configured to use a rising edge of the 1PPS signal of the first time synchronization information as a trigger condition, and a pre-configured high frequency between the rising edges of two adjacent 1PPS signals in the plurality of consecutive 1PPS signals The clock is counted, and a plurality of corresponding cycle count values are obtained;

And an averaging process for averaging the plurality of cycle count values to obtain an average period value of an average period of the plurality of consecutive 1PPS signals.

10. The time synchronization information transmitting apparatus according to claim 8, wherein said time synchronization processing module comprises

 a counter, configured to use a rising edge of the 1PPS signal of the first time synchronization information as a trigger condition, and count the high frequency clock within a duration of a plurality of consecutive 1PPS signals to obtain a total cycle count value;

 And an averaging calculator, configured to divide the total cycle count value by the number of the plurality of consecutive 1PPS signals to obtain an average period value of the plurality of consecutive 1PPS signals.

A time synchronization information transmission method, comprising:

 Receiving first time synchronization information from the upper-level time synchronization device, where the first time synchronization information is local time synchronization information of the upper-level time synchronization device, and includes a second pulse 1PPS signal and a time-time ToD signal;

 Calculating an average period of the plurality of consecutive 1PPS signals in the first time synchronization information, and adjusting a period of the next or next group of 1PPS signals to the average period;

 The ToD signal and the periodically adjusted 1PPS signal are configured as second time synchronization information and sent to the next-stage time synchronization device for time synchronization processing by the next-stage time synchronization device.

The method according to claim 11, wherein the calculating an average period of the plurality of consecutive 1PPS signals in the first time synchronization information comprises:

 Provide a pre-configured high frequency clock;

 Using the rising edge of the 1PPS signal of the first time synchronization information as a trigger condition, respectively counting the high frequency clock within the duration of each of the plurality of consecutive 1PPS signals, and obtaining more Corresponding cycle count values;

 The plurality of cycle count values are averaged to obtain an average period value of an average period of the plurality of consecutive 1PPS signals.

13. The method according to claim 11, wherein the calculating the first time The average period of multiple consecutive 1PPS signals in the synchronization information includes:

 Provide a pre-configured high frequency clock;

 Using the rising edge of the 1PPS signal of the first time synchronization information as a trigger condition, counting the high frequency clock within a duration of a plurality of consecutive 1PPS signals to obtain a total cycle count value;

 The average period count value is divided by the number of the plurality of consecutive 1PPS signals to obtain an average period value of the plurality of consecutive 1PPS signals.