CN109155672B - Method and system for transmitting optical signal in passive optical network - Google Patents

Abstract

The present application relates to a passive optical network system, and more particularly, to signal transmission of an optical line terminal. The optical line terminal sequences the uplink light sent by the optical network unit according to the intensity, determines the sequence of sending the uplink light by the optical network unit and the corresponding reset time, can effectively reduce the leader sequence in the optical signal, and enables the optical line terminal to receive more uplink optical signals in unit time.

Description

Method and system for transmitting optical signal in passive optical network

technical field

Embodiments of the present invention relate to passive optical network systems, and in particular, to signal transmission of optical line terminals.

Background technique

The main components of a passive optical network PON (Passive Optical Network) system include an optical line terminal OLT (Optical Line Terminal), an optical network unit ONU (Optical Network Unit), and an optical splitter connecting the OLT and the ONU. In the PON system, there is a one-to-many optical fiber transmission and access technology between the OLT and the ONU. The key technologies of passive optical network PON application mainly include: OLT downstream signal adopts continuous broadcast mode, and upstream signal adopts time division multiple access burst mode. Detailed descriptions of PON systems can be found in patent documents CN102301670B, CN103248422A, CN103297866B, CN104243092A, or https://en.wikipedia.org/wiki/Passive optical network , which are incorporated herein by reference.

For the OLT, its built-in optical module will receive upstream light with different optical powers. When the received optical power of two adjacent upstream lights is quite different, it will take a long time for the built-in optical module of the OLT to establish the threshold voltage. level, otherwise it will cause the received signal to convert incorrectly. An improved approach is to quickly establish the threshold by using a reset signal RESET in the built-in optical module. However, the frequent reset process still occupies the already tight upstream bandwidth.

Therefore, the industry is eager for a solution that enables the OLT to receive more upstream optical signals per unit time.

SUMMARY OF THE INVENTION

In view of this, embodiments of the present invention provide a method and system for transmitting optical signals in a passive optical network, so that the OLT can receive more uplink optical signals per unit time.

In a first aspect, an embodiment of the present invention provides a method for transmitting an optical signal in a passive optical network. The optical line terminal acquires the intensities of uplink optical signals sent by multiple optical network units. The optical line terminal sorts the intensities of the uplink optical signals to determine the order in which the optical network unit subsequently sends the uplink optical signals. The optical line terminal determines the reset time corresponding to each optical network unit according to the sorting result. The optical line terminal sends an instruction to the optical network unit, so that the optical network unit sends subsequent uplink optical signals to the optical line terminal according to the sequence and the corresponding reset time. This implementation method effectively reduces the intensity difference between different uplink optical signals by sorting multiple optical network units according to the intensity of the uplink optical signals, thereby reducing the time required for the reset of the optical line terminal, and making the OLT within a unit time Can receive more upstream optical signals.

In a possible implementation manner, the above steps may also be performed using other devices instead of the optical line terminal.

In a possible implementation manner, the ordering of the intensity of the uplink optical signals by the optical line terminal and the order in which the optical line terminal determines the uplink optical signal sent by the optical network unit may be performed in two steps. That is, the intensities of the uplink optical signals are first sorted, and then the order in which the optical network units send the uplink optical signals and the reset time corresponding to each optical network unit are determined according to the sorting result.

In a possible implementation manner, the intensities of the uplink optical signals may be sorted from small to large, or from large to small. This implementation mode reduces the voltage fluctuation caused by the fluctuation of different uplink optical signal strengths in a period, thereby reducing the time required for the reset of the optical line terminal.

Further, in a possible implementation manner, the optical line terminal instructs the optical network unit to alternately transmit uplink optical signals in sequence and reverse order in multiple consecutive cycles, so as to further reduce the two optical networks between each transmission cycle. The reset time required for the unit.

In a possible implementation manner, the optical line terminal instructs the optical network unit to determine the length of the preamble sequence of the uplink optical signal according to the corresponding reset time. Because the preamble sequence does not carry data, it is used to cover the reset time of the optical line terminal. If the length of the preamble sequence is insufficient, the data cannot be correctly identified and converted by the optical line terminal; if the length of the preamble sequence is redundant, the amount of data transmitted in the upstream optical signal will be reduced. The optical network unit determines the length of the preamble sequence of the uplink optical signal according to the corresponding reset time, so that as much valid data as possible is sent in the uplink optical signal sent once. The length of the preamble sequence in this application is also called the number of preamble sequence bits, that is, the amount of content in the preamble sequence.

In another possible implementation, the optical line terminal determines the length of the preamble sequence of the upstream optical signal corresponding to the reset time, and instructs the optical network unit to send the upstream optical signal to the optical line terminal according to the length of the preamble sequence corresponding to the corresponding reset time.

In a possible implementation manner, the optical line terminal may determine a unified reset time for each optical network unit according to the maximum value of the difference between the intensities of two adjacent upstream optical signals that have been sorted. This implementation ensures that the data sent by each optical line terminal can be correctly received.

In another possible implementation manner, the optical line terminal may determine the reset time corresponding to each optical network unit according to the difference between the intensities of every two adjacent uplink optical signals sorted. This implementation further improves the number of uplink optical signals that the OLT can receive in a unit time.

In a possible implementation manner, after receiving the uplink optical signal of each optical network unit, the optical line terminal may acquire the uplink optical signal strength of each optical network unit through detection. In this implementation manner, the uplink optical signal strength of each optical network unit is acquired in real time with high accuracy.

In another possible implementation manner, the optical line terminal may read the uplink optical signal strength corresponding to each optical network unit from the storage module. Further, the correspondence between the uplink optical signal strength in the storage module and each optical network unit may be stored in the storage module after being detected by the optical line terminal, or may be directly input into the storage module from the outside. In this implementation manner, the optical line terminal has the capability of rapid response and is easy to install and replace.

In a possible implementation manner, the optical line terminal can periodically detect the received uplink optical signal strength of each optical network unit, and compare it with the stored uplink optical signal strength data. When the newly added optical network unit has the uplink optical signal strength, the uplink optical signal strength is sorted again to determine the sequence and reset time of the optical network unit sending the uplink optical signal.

In another possible implementation manner, the optical line terminal can also detect the received uplink optical signal strength of each optical network unit in real time, and compare it with the stored uplink optical signal strength data. Or when the uplink optical signal strength of the newly added optical network unit is added, the uplink optical signal strength is sorted again to determine the sequence and reset time of the optical network unit sending the uplink optical signal.

In the second aspect, in combination with the above technical solutions, an embodiment of the present invention provides a method for transmitting an optical signal, including:

The optical line terminal acquires the first intensity of the first uplink optical signal sent by the first optical network unit;

The optical line terminal acquires the second intensity of the second uplink optical signal sent by the second optical network unit, and the second intensity is not equal to the first intensity;

The optical line terminal determines the order in which the first optical network unit sends the third uplink optical signal and the corresponding reset time with reference to the first intensity and the second intensity;

The optical line terminal determines the order in which the second optical network unit sends the fourth uplink optical signal and the corresponding reset time with reference to the first intensity and the second intensity;

The optical line terminal sends an instruction to the first optical network unit and the second optical network unit, so that the first optical network unit knows the sequence of sending the third uplink optical signal and the corresponding reset time, and the second optical network unit knows to send the fourth uplink optical signal. The sequence of optical signals and the corresponding reset time.

Alternatively, in a possible implementation manner, the optical line terminal refers to the first intensity and the second intensity to determine the order in which the first optical network unit sends the third uplink optical signal and the corresponding reset time, and the second optical network unit The sequence of sending the fourth uplink optical signal and the corresponding reset time. The two determined steps in the various implementations of the present invention may be completed in one step.

Alternatively, in a possible implementation manner, the optical line terminal determines the first sequence number of the third uplink optical signal sent by the first optical network unit with reference to the first intensity and the second intensity, and The corresponding first reset time. The optical line terminal determines the second sequence number and the corresponding second reset time of the fourth uplink optical signal sent by the second optical network unit with reference to the first intensity and the second intensity. Directly determine the sequence number for easy storage and transmission.

In a possible implementation manner, the optical line terminal sends an indication to the first optical network unit and the second optical network unit. The first optical network unit receives the instruction, and sends a third upstream optical signal to the optical line terminal with reference to the first sequence number and the first reset time. The second optical network unit receives the instruction, and sends the fourth uplink optical signal to the optical line terminal with reference to the second sequence number and the second reset time.

In another possible implementation manner, the optical line terminal refers to the first intensity and the second intensity to determine the first sequence number and the corresponding first sequence number of the third uplink optical signal sent by the first optical network unit A reset time, and the second sequence number of the fourth uplink optical signal sent by the second optical network unit and the corresponding second reset time.

Alternatively, in a possible implementation manner, the optical line terminal sends a first indication to the first optical network unit with reference to the first sequence number and the first reset time. The optical line terminal sends a second indication to the second optical network unit with reference to the second sequence number and the second reset time. The first optical network unit receives the first indication and sends the third uplink optical signal. The second optical network unit receives the second indication and sends the fourth uplink optical signal.

In a third aspect, an embodiment of the present invention provides an optical line terminal. The optical line terminal has a function capable of implementing the above method. The functions may be implemented by hardware, or by executing corresponding software in hardware. The hardware or software includes one or more modules corresponding to the above functions, and the modules may be hardware and/or software.

In a possible implementation manner, the optical line terminal includes:

The signal transmission module is used for receiving the uplink optical signal from the optical network unit, and sending the downlink light to the optical network unit;

a detection module, used for detecting the intensity of the uplink optical signal sent by the optical network unit received by the optical line terminal;

The sorting module is used to sort the uplink optical signal intensity sent by each optical network unit to determine the order in which each optical network unit sends the uplink optical signal, and send the sending order to the optical network unit in the downlink light through the signal transmission module ;

a reset time determination module, configured to determine the reset time of each optical network unit according to the result of the uplink optical signal intensity sorting, and send the reset time to the optical network unit in the downlink light through the signal transmission module; and

Memory module for storing sequence and reset time.

In a fourth aspect, an embodiment of the present invention provides a passive optical network system, which utilizes the optical line, terminal and transmission method of the above implementation manner. A passive optical network system includes an optical line terminal, an optical splitter and a plurality of optical network units. The optical line terminal and the optical network unit are connected through an optical splitter. The optical line terminal has a function capable of realizing the above-mentioned intelligent ordering. The functions may be implemented by hardware, or by executing corresponding software in hardware. The hardware or software includes one or more modules corresponding to the above functions, and the modules may be hardware and/or software.

In a possible implementation, the passive optical network system includes:

Multiple optical network units;

optical splitters; and

Optical line terminals, connected to optical network units through optical splitters, include:

a signal transmission unit, configured to receive the uplink optical signal sent from the optical network unit, and send the downlink light to the optical network unit,

a processor, configured to sort the intensity of the uplink optical signals to determine the order in which the optical network unit sends the uplink optical signals and the reset time corresponding to each optical network unit, and send the order and reset time to the optical network unit, and

a memory for storing the sequence and the reset time corresponding to each optical network unit;

The optical network unit sends the uplink optical signal to the optical line terminal according to the sequence indicated by the optical line terminal and the reset time.

Through the above solution, the embodiments of the present invention can flexibly identify the strength of the uplink optical signals, so that the uplink optical signals are sorted cyclically according to the strength. In this way, the optical intensity difference between adjacent upstream optical signals can be reduced, the DC voltage threshold can be quickly established, and the preamble preamble sequence bits of each sequence can be reduced, so that the OLT can receive more upstream optical signals per unit time.

Description of drawings

1 is a schematic diagram of a passive optical network PON system provided according to a possible embodiment of the present invention;

2 is a schematic diagram of a light-receiving circuit of an optical line terminal OLT built-in optical module provided according to a possible embodiment of the present invention;

FIG. 3 is a schematic diagram showing the variation of the optical signal voltage amplitude signal received by the optical line terminal OLT according to a possible embodiment of the present invention;

4 is a flowchart of a method for transmitting an optical signal in a passive optical network PON system according to a possible embodiment of the present invention;

FIG. 5 is a schematic diagram showing the variation of the optical signal voltage amplitude signal received by the optical line terminal OLT according to a possible implementation manner of the present invention;

6 is a schematic structural diagram of a passive optical network PON system provided according to a possible embodiment of the present invention;

7 is a schematic block diagram of a partial structure of an optical line terminal OLT provided according to a possible embodiment of the present invention;

8 is a schematic block diagram of a partial structure of an optical line terminal OLT provided according to another possible implementation manner of the present invention;

9 is a flowchart of a method for transmitting an optical signal in a passive optical network PON system according to a possible embodiment of the present invention;

10 is a flowchart of a method for transmitting an optical signal in a passive optical network PON system according to another possible embodiment of the present invention;

11 is a flowchart of a method for transmitting an optical signal in a passive optical network PON system according to another possible embodiment of the present invention;

12 is a flowchart of a method for transmitting an optical signal in a passive optical network PON system provided according to another possible embodiment of the present invention;

FIG. 13 is an architectural diagram of an optical line terminal OLT provided according to a possible implementation manner of the present invention.

Detailed ways

FIG. 1 is a schematic diagram of a passive optical network PON system provided according to a possible embodiment of the present invention. As shown in FIG. 1 , in a possible implementation manner, the PON system includes an optical line terminal OLT 10 , a plurality of optical network units ONU 20 and an optical splitter 30 . The OLT 10 is connected to the optical splitter 30 . The optical splitter 30 is connected to the plurality of ONUs 20 . The optical signal sent by the ONU 20 to the OLT 10 via the optical splitter 30 is an uplink optical signal, and the optical signal received by the ONU 20 from the OLT 10 via the optical splitter 30 is a downlink optical signal. A plurality of ONUs 20 send upstream light to the OLT 10 in a time division multiple access burst mode, that is, within a period, a plurality of ONUs 20 send upstream light to the OLT 10 in sequence.

In some places in this application, "uplink light" is used to refer to "uplink optical signal", which does not hinder the understanding of those skilled in the art under the condition that it is consistent with the spirit of the invention.

In the embodiment of FIG. 1, the ONUs 20 are identified by numbers 1 to 3, respectively, which does not mean that the ONUs 20 are required to be the same device. The ONU 20 may be the same or different devices, including ONT (Optical Network Terminal) and the like.

FIG. 2 is a schematic diagram of a light receiving circuit of an optical line terminal OLT 10 built-in optical module provided according to a possible implementation manner of the present invention. As shown in Figure 2, for the OLT 10, when its built-in optical module receives the upstream light of each ONU 20, it resets the built-in optical module at the starting position of the upstream light, so that the energy storage capacitor C2 can be quickly charged and discharged to achieve rapid setup The purpose of the threshold level.

Specifically, when an uplink burst optical signal is received, the current flowing through the PD/APD diode will change proportionally, and the output side of the Transconductance Amplifier (TIA) will generate a voltage value corresponding to the light intensity, which will give Capacitor charging at the LN- pin of 149CL. Due to the voltage hysteresis characteristic of capacitor charging, there will be a voltage difference between LN+ and LN-, and the light intensity of the upstream light sent from the same ONU 20 is stable. At this time, the 149CL amplifier can normally reflect the optical signal value. When the upstream light intensity difference sent by two adjacent ONUs is large, for example, the light intensity of the second upstream light is smaller than that of the previous upstream light, when the second upstream light comes over, the voltage on C2 will be higher than that of the LN+ pin. The higher voltage causes amplifier 149CL to misjudge the first few logic 1 signal bits as logic 0s. After several upstream optical bits, the discharge of C2 reduces the DC threshold, and the voltage amplifier 149CL can output the data of the second upstream optical normally. Similarly, if the intensity of the second upstream light is stronger than the first one, the charging of C2 will be too slow, so that the DC threshold rises too slowly, resulting in the optical signal of the second ONU 20 in the first few days. A bit data conversion error occurred.

In order to prevent data conversion errors, it is possible to increase the switch switching path. At the beginning of each sequence, the RESET reset control method is used to manually control the two switching devices M5 and M6 to open when the upstream optical switching of different ONUs, so as to realize the upstream optical switching. Fast discharge of C2 when strong light is cut off from weak light, or fast charging of C2 when weak light is cut off from strong light.

Figure 3 reflects the voltage value changes of LN+ and LN- when the light changes from strong light to weak light. It can be seen from the voltage of LN- that when the second sequence arrives, the LN- voltage signal will have a slow decline process due to the presence of the reset signal RESET signal, and the amplifier 149CL cannot correctly convert the optical signal data to the back end. After the reset is completed, the DC threshold is established and reaches a relatively stable value. At this time, the amplifier 149CL can convert data correctly.

As can be seen from FIG. 3 , during the reset process, the ONU 20 can only send the preamble sequence bit that does not include data, and after the reset process ends, the delimiter Delimiter is used to inform that the data payload Payload/Data needs to be sent next. Therefore, under the condition that the data payload Payload/Data in the uplink light sent each time remains unchanged, the longer the reset time is, the ONU 20 needs to send more preamble sequences, thus requiring a longer sending time. In particular, when the difference between adjacent optical powers is larger, a longer reset time is required. In a PON system, one OLT 10 device is usually connected to dozens of ONU 20 devices at the same time, and the uplink communication adopts the time division multiple access burst mode, which requires multiple resets. It can be seen that within the same Guard time, reducing the reset time enables more ONUs 20 to send upstream light.

The embodiment of the present invention reduces the reset time, thereby improving the optical signal transmission efficiency of the PON system.

FIG. 4 is a flowchart of a method for transmitting an optical signal in a passive optical network PON system according to a possible embodiment of the present invention. As shown in Figure 4, the method includes the following steps.

Step 100, start.

Step 101, the OLT acquires the upstream optical intensity of each ONU.

Errors in the production and installation process, or the use of different types of ONU devices, or signal attenuation due to different quality and length of connecting optical cables, may cause inconsistencies in the upstream optical intensity of each ONU. The OLT obtains the upstream light intensity of each ONU, thereby establishing a corresponding relationship between the upstream light intensity and each ONU.

In a possible implementation manner, after receiving the upstream light of each ONU, the OLT may acquire the upstream light intensity of each ONU through detection. Various detection methods in the prior art can be incorporated into the embodiments of the present invention, such as CN100505592C. Further, the OLT can store the detected light intensity and the corresponding relationship with the ONU in the storage module. The storage module can be built in the OLT or an external storage device.

In another possible implementation, the OLT may read the upstream light intensity corresponding to each ONU from the storage module. Further, the corresponding relationship between the upstream light intensity in the storage module and each ONU may be stored in the storage module after being detected by the OLT, or may be directly input into the storage module from the outside.

In a possible implementation manner, the OLT obtains the upstream light intensity of each ONU through detection. The OLT can test the light intensity of the ONU first, and then instruct the ONU to send upstream light containing data. The OLT can also directly receive the upstream light containing data sent by the ONU, and determine the light intensity of the ONU while receiving the data. Further, a longer RESET time can be allocated to each ONU to avoid data conversion errors.

Step 102, the OLT determines the sending order of the ONUs by sorting the upstream light according to the intensity.

The result of sorting the uplink light according to the intensity can be from small to large, or from large to small, or it can be interleaved from small to large and from large to small. The result of sorting can be reflected in one cycle, or it can be reflected in multiple cycles. Cyclic representations in multiple cycles can be cycled sequentially or in reverse order. As shown in Figure 1, for example, if the upstream light intensity comes from ONU 2, ONU 3, and ONU 1 respectively, the order can be ONU 2, ONU 3, ONU 1, that is, the upstream light intensity is sorted from small to large; it can also be ONU 1, ONU 3, ONU 2, that is, the uplink light intensity is sorted from large to small; it can also be ONU2, ONU3, ONU 1, ONU 2, ONU 3, ONU 1, that is, the uplink light intensity is sorted from small to large and the sequence is repeated; It can also be ONU2, ONU 3, ONU 1, ONU 1, ONU 3, ONU 2, that is, the uplink light intensity is sorted from small to large and repeated in reverse order.

In a possible implementation manner, the OLT may perform the sorting of the uplink light by intensity and determining the sending order of the ONUs in two steps respectively.

As shown in Figure 5, the ONU sends the upstream light to the OLT according to the sorting result of the upstream light intensity, so that the difference between the upstream light intensities sent by each ONU is reduced, thereby shortening the time required to reset the RESET, and making the ONU send the upstream light. In the upstream optical signal, the number of bits of the preamble sequence can be reduced, so that more ONUs can send upstream light in a unit time, thereby transmitting more data payloads Payload/Data.

In other words, no matter whether the difference of the upward light intensity is positive or negative, the OLT has to be reset, so the reset RESET time is related to the absolute value of the difference between the upward light intensity. When the upstream light intensity sent by the ONU is arranged according to the intensity, compared with the irregular fluctuation, the required reset time is the least, that is,

For example, suppose that the upstream light intensity values of ONU 1, ONU 2, and ONU 3 are 4, 1, and 3, respectively. If the upstream lights are sent according to numbers instead of sorting by size, the light intensity differences corresponding to two RESETs between the three upstream lights are 4-1=3 and |1-3|=2, respectively. However, if the upstream light is sent in the order from small to large, that is, ONU 2, ONU 3, and ONU 1, the light intensity difference corresponding to two RESETs between the three upstream lights is |1-3|=2 and |3-4|=1, so the RESET time is shortened. It can be seen that when the number of devices is further increased, the scheme of determining the ONU sending order according to the upstream light intensity provided by the embodiment of the present invention can effectively reduce the time of RESET, so that the ONU can reduce the preamble of the sent preamble, thereby making the OLT within the unit time. Can receive more upstream optical signals.

Step 103, the OLT determines the reset RESET time of the ONU according to the sorting result of the upstream light intensity of the ONU.

In a possible implementation manner, the OLT determines a unified RESET time for each ONU according to the sorting result of the uplink light intensity. Specifically, the OLT determines the RESET time according to the maximum value of the difference between the ordered two adjacent upstream light intensities, and then notifies each ONU of the unified RESET time. In this embodiment, the RESET time determined according to the maximum value of the upstream light intensity difference ensures that the data in the upstream light sent by each ONU can be effectively identified and converted, thereby avoiding conversion errors.

In another possible implementation manner, the OLT determines the corresponding RESET time for each ONU according to the sorting result of the uplink light intensity. Specifically, the OLT determines the RESET time of each ONU according to the difference between every two adjacent upstream light intensities sorted, and then notifies each ONU of the corresponding RESET time. In other words, an ONU whose upstream optical intensity changes less than the previous ONU has a shorter RESET time, and an ONU whose upstream optical intensity changes more than the previous ONU has a longer RESET time. In this embodiment, the ONU can determine the preamble sequence to be sent according to the actual RESET needs, so that the OLT can receive more upstream optical signals per unit time.

In a possible implementation, the OLT may store the sorting result and the reset RESET time in the storage module. When the OLT is replaced or restarted after a power failure, it is not necessary to repeat the above steps.

In a possible implementation manner, the light intensity data corresponding to different ONU devices is pre-stored in the storage module, and the light intensity data may come from factory settings or data analysis within a period of time. The reset time can be assigned directly to the ONU.

Step 104, the OLT instructs the ONU to send the upstream light according to the sorting result and the reset RESET time.

The ONU can determine the length of the preamble sequence to be sent according to the RESET time sent by the OLT, and then send the upstream light to the OLT in the order indicated by the OLT. The preamble sequence Preamble does not carry data and is used to cover the RESET time to avoid premature transmission of data and conversion errors in the OLT.

In a possible implementation manner, the OLT may also directly determine and indicate the length of the preamble sequence that the ONU needs to send.

In a possible implementation, the detection and sorting of light intensity may not be completed by the OLT device, for example, it may be completed by an optical splitter, or a detection and/or sorting device may be placed between the OLT and the ONU To be done.

In a possible implementation manner, the OLT can instruct the ONU to send the upstream light, and can also list the transmission time in one cycle or multiple cycles for each ONU device, and then instruct the ONU the time to send the upstream light. In this embodiment, the ONU determines the length of the preamble sequence to be sent by itself according to the sending time.

In the embodiment of the present invention, the upstream light intensity sent by the ONU is intelligently detected by the built-in optical module of the OLT within a time division multiple access sequence period, and the upstream light sequences of all the ONUs are arranged in descending order of intensity. Figure 5 shows the voltage situation of LN+ and LN- under this embodiment. It can be seen that the uplink optical sequences sent by multiple ONUs are arranged in order according to the light intensity, so that the light intensity difference between adjacent optical sequences is reduced, the required RESET reset control time is shorter, and LN- can reach a threshold faster.

After the required reset time is shortened, the preamble of each sequence, that is, the bits required for the Preamble sequence can be reduced, and the total time occupied by the corresponding ONU upstream light can be shortened. When the guard time Guard time remains unchanged, the OLT can be More uplink optical signals can be received per unit time.

In a possible implementation manner, the OLT instructs the ONU to alternately transmit upstream light in sequence and in reverse order in multiple consecutive cycles, so as to further reduce the RESET time required by the ONU between each transmission cycle. A cycle referred to here is that multiple ONU devices all send uplink light once in sequence.

Specifically, in order to ensure that the light intensity difference will not be too large during the cyclic switching of each cycle, the uplink light sequence is sorted according to the cycle, from strong to weak → from weak to strong → from strong to weak. There will be no excessive light intensity difference at any time, ensuring that the number of bits of the preamble sequence is less and the duration is shorter. For example, the examples of ONU 2, ONU 3, ONU 1, ONU 1, ONU 3, and ONU 2 mentioned above. Through the cycle of light intensity from small to large and then from large to small, the drastic change of switching from the ONU with the largest light intensity to the ONU with the smallest light intensity is avoided when the two cycles are switched, and the reset time is shortened.

In a possible implementation, the OLT periodically detects the upstream light intensity of each ONU.

When an ONU device is added or replaced, the upstream optical sequence will be added, or the optical intensity sequence will be changed. The OLT in this embodiment can automatically and periodically detect the intensity of all upstream lights, so even if such changes occur, the OLT can re-order all upstream lights according to a predetermined light intensity rule. That is, as shown in FIG. 5 , it is ensured that all the upstream lights are sorted in order according to the light intensity.

Specifically, the OLT can periodically compare the received uplink optical intensity of each ONU with the data in the storage module, and when it finds that there is an inconsistency or newly added ONU uplink optical intensity, the ONU devices are sorted and determined again. reset time.

In another possible implementation, the OLT can also compare the received uplink optical intensity of each ONU with the data in the storage module in real time. The ONU devices are again sequenced and the reset time determined.

FIG. 6 is a schematic structural diagram of a passive optical network PON system provided according to a possible embodiment of the present invention. As shown in FIG. 6 , the OLT 10 is connected to a plurality of ONUs 20 through an optical splitter 30 . The OLT 10 includes a signal transmission unit 11 , a processor 12 and a memory 13 .

The signal transmission unit 11 is configured to receive the upstream light sent from the ONU 20 and send the downstream light to the ONU 20 .

The processor 12 is configured to sort the intensity of the upstream light sent by the ONU 20 to determine the sequence of the upstream light sent by the ONU 20 and the reset time corresponding to each ONU 20 , and send the sorting result and the reset time to the ONU 20 .

The memory 13 is used for storing the result of sorting the ONUs 20 according to the transmitted upstream light intensity by the processor 12 and the reset time corresponding to each ONU 20 .

The ONU 20 sends upstream light to the OLT according to the sequence and reset time indicated by the OLT 10 .

FIG. 7 is a schematic block diagram of a partial structure of an optical line terminal OLT provided according to a possible implementation manner of the present invention. As shown in FIG. 7 , the OLT includes a signal transmission module 14 , a detection module 15 , a sorting module 16 , a reset time determination module 17 and a storage module 18 .

The signal transmission module 14 is used for receiving upstream light from the ONU and sending downstream light to the ONU.

The detection module 15 is used to detect the upstream light intensity sent by the ONU and received by the OLT.

The sorting module 16 is configured to sort the upstream light intensity sent by each ONU, and send the sorting result to the ONU in the downstream light through the signal transmission module 14 .

The reset time determination module 17 is configured to determine the reset time of each ONU device according to the result of the uplink light intensity sorting, and send the reset time to the ONU in the downlink light through the signal transmission module 14 .

The storage module 18 is used for storing the sorting result of the sorting module 16 and the reset time determined by the reset time determining module 17 .

In a possible implementation manner, the sorting module 16 sorts the intensities of the uplink light according to the ascending order, or the ascending order.

In a possible implementation manner, the sequencing module 16 instructs the ONU of the optical network unit to alternately transmit upstream light in sequence and in reverse order in multiple consecutive cycles.

In a possible implementation manner, the reset time determining module 17 instructs the optical network unit ONU to determine the length of the preamble sequence of the upstream light according to the corresponding reset time.

In a possible implementation, the reset time determination module determines 17 the length of the preamble sequence of the upstream light corresponding to the corresponding reset time, and the reset time determination module 17 instructs the optical network unit ONU to send the upstream light to the optical line terminal OLT according to the length of the preamble sequence .

In a possible implementation manner, the reset time determination module 17 determines a unified reset time for each ONU according to the maximum value of the difference between the intensities of two adjacent upstream lights sorted.

In a possible implementation manner, the reset time determination module 17 determines the reset time corresponding to each ONU of the optical network unit according to the difference between every two adjacent uplink light intensities sorted.

In a possible implementation manner, the detection module 15 stores the intensity of the uplink light of each optical network unit ONU acquired by detection into the storage module 18 .

In a possible implementation manner, the detection module 15 periodically detects the received upstream light intensity of each ONU ONU, and compares it with the stored upstream light intensity data. When adding, the sorting module 16 sorts the intensity of the upstream light again to determine the order in which the ONU sends the upstream light, and the reset time determination module 17 determines the reset time.

In a possible implementation, the detection module 15 detects the received uplink light intensity of each ONU in real time, and compares it with the stored uplink light intensity data. When the time is increased, the sorting module 16 sorts the intensity of the uplink light again to determine the order in which the optical network unit ONU sends the uplink light, and the reset time determination module 17 determines the reset time.

FIG. 8 is a schematic block diagram of a partial structure of an optical line terminal OLT provided according to another possible implementation manner of the present invention. As shown in FIG. 8 , different from the embodiment shown in FIG. 7 , this embodiment further includes a sending order determination module 19 for determining the order in which the ONU sends the subsequent uplink light according to the sorting result of the sorting module 16 , and The sequence is sent to the ONU in the downstream light through the signal transmission module 14 .

FIG. 9 is a flowchart of a method for transmitting an optical signal in a passive optical network PON system according to a possible embodiment of the present invention. As shown in Figure 9, after sorting the upstream optical signal strengths of ONU 1 and ONU 2, the OLT determines the sending sequence and reset time, and sends the sending sequence and reset time to the ONU, instructing ONU 1 to send the upstream optical signal second, and the ONU 2 The first one to send the upstream optical signal.

FIG. 10 is a flowchart of a method for transmitting an optical signal in a passive optical network PON system according to another possible embodiment of the present invention. As shown in Figure 10, after sorting the upstream optical signal strengths of ONU 1 and ONU 2, the OLT determines the transmission sequence and reset time, and further determines the length of the preamble sequence, and sends the transmission sequence and preamble sequence length to the ONU, indicating that ONU 1 Two send upstream optical signals, and ONU 2 is the first to send upstream optical signals.

FIG. 11 is a flowchart of a method for transmitting an optical signal in a passive optical network PON system according to another possible embodiment of the present invention. As shown in Figure 11, after sorting the upstream optical signal strengths of ONU 1 and ONU 2, the OLT determines the sending sequence number and reset time, and sends the sending sequence number and reset time to the ONU, indicating that ONU 1 is the second to send the upstream optical signal , ONU 2 is the first to send the upstream optical signal.

FIG. 12 is a flowchart of a method for transmitting an optical signal in a passive optical network PON system according to another possible embodiment of the present invention. As shown in Figure 12, after sorting the upstream optical signal strengths of ONU 1 and ONU 2, the OLT determines the sending sequence and reset time, and sends the sending time to the ONU, indicating that ONU 1 is the second to send the upstream optical signal, and ONU 2 is the first to send the upstream optical signal. send the upstream optical signal.

FIG. 13 is an architectural diagram of an optical line terminal OLT provided according to a possible implementation manner of the present invention. As shown in Figure 13, the OLT includes a receiver, a transmitter, a processor, and a memory distributed on a communication bus. Program codes and applications are stored in the memory.

In a possible implementation manner, the ONU and/or the optical splitter may also have the architecture shown in FIG. 13 .

From the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented by hardware, firmware, or a combination thereof. When implemented in software, the functions described above may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage medium can be any available medium that a computer can access. By way of example and not limitation, computer readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage media or other magnetic storage devices, or be capable of carrying or storing instructions or data structures in the form of desired program code and any other medium that can be accessed by a computer. also. Any connection can be appropriately made into a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable , fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, wireless, and microwave are included in the fusing of the pertinent medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and blu-ray disc, where disks usually reproduce data magnetically, and discs Lasers are used to optically copy data. Combinations of the above should also be included within the scope of computer-readable media.

In a word, the above descriptions are only preferred embodiments of the technical solutions of the present invention, and are not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (17)

1. A method of transmitting an optical signal, comprising:

the optical line terminal acquires a first intensity of a first uplink optical signal sent by a first optical network unit;

the optical line terminal acquires a second intensity of a second uplink optical signal sent by a second optical network unit, wherein the second intensity is not equal to the first intensity;

the optical line terminal determines the order of sending the third uplink optical signal by the first optical network unit and the corresponding reset time by referring to the first intensity and the second intensity;

the optical line terminal determines the order of sending fourth uplink optical signals by the second optical network unit and the corresponding reset time by referring to the first intensity and the second intensity;

the optical line terminal sends an instruction to the first optical network unit and the second optical network unit, so that the first optical network unit learns the sequence of sending the third uplink optical signal and the corresponding reset time, and the second optical network unit learns the sequence of sending the fourth uplink optical signal and the corresponding reset time.

2. The method of claim 1, wherein the first and second intensities are ordered by the optical line termination according to a small to large order, or a large to small order.

3. The method of claim 2, wherein the order in which the first optical network unit transmits the third upstream optical signals and the order in which the second optical network unit transmits the fourth upstream optical signals are such that upstream optical signals are transmitted alternately in successive periods.

4. The method according to any of claims 1-3, further comprising the optical line terminal instructing the first optical network unit and the second optical network unit to determine a first preamble sequence length of the third upstream optical signal and a second preamble sequence length of the fourth upstream optical signal according to the corresponding reset times.

5. The method according to any of claims 1 to 3, further comprising determining, by the optical line terminal, that the third upstream optical signal corresponds to a first preamble sequence length of the corresponding reset time and the fourth upstream optical signal corresponds to a second preamble sequence length of the corresponding reset time, and instructing, by the optical line terminal, the first optical network unit and the second optical network unit to send the third upstream optical signal and the fourth upstream optical signal to the optical line terminal according to the first preamble sequence length and the second preamble sequence length.

6. The method of claim 1, wherein the first intensity and the second intensity are obtained by the optical line terminal through detection.

7. The method of claim 1, wherein the first and second intensities are read by the optical line terminal from a storage module.

8. The method according to claim 7, further comprising the olt periodically detecting a third strength of the received third uplink optical signal and a fourth strength of the received fourth uplink optical signal, comparing the detected third strength and fourth strength with the stored first strength and second strength, when the detected first strength and second strength are inconsistent or newly added, the olt determining, with reference to the third strength and the fourth strength, an order in which the first onu transmits a fifth uplink optical signal and a corresponding reset time, and the olt determining, with reference to the third strength and the fourth strength, an order in which the second onu transmits a sixth uplink optical signal and a corresponding reset time.

9. The method according to claim 7, further comprising the olt detecting a third intensity of the received third uplink optical signal and a fourth intensity of the received fourth uplink optical signal in real time, comparing the detected third intensity and the stored fourth intensity with the stored first intensity and the stored second intensity, when the detected third intensity and the stored second intensity are inconsistent or newly added, the olt determining, with reference to the third intensity and the fourth intensity, an order in which the first onu transmits a fifth uplink optical signal and a corresponding reset time, and the olt determining, with reference to the third intensity and the fourth intensity, an order in which the second onu transmits a sixth uplink optical signal and a corresponding reset time.

10. A passive optical network system, comprising:

a plurality of optical network units;

an optical splitter; and

the optical line terminal is connected with the plurality of optical network units through the optical splitter and comprises:

a signal transmission unit for receiving the upstream optical signal transmitted from the optical network unit and transmitting downstream light to the plurality of optical network units,

a processor for sequencing the intensity of the uplink optical signals to determine an order in which the plurality of optical network units transmit subsequent uplink optical signals and reset times corresponding to the plurality of optical network units, and transmitting the order and the reset times to the plurality of optical network units, and

a memory for storing the order and the reset times corresponding to the plurality of optical network units;

wherein the plurality of optical network units send the subsequent uplink optical signal to the optical line terminal according to the sequence indicated by the optical line terminal and the reset time.

11. An optical line terminal comprising:

the optical network unit comprises a signal transmission module, a signal receiving module and a signal processing module, wherein the signal transmission module is used for receiving an uplink optical signal from the optical network unit and sending downlink light to the optical network unit;

a detection module, configured to detect the intensity of the uplink optical signal sent by the optical network unit and received by the optical line terminal;

a sorting module, configured to sort the intensity of the uplink optical signal sent by each optical network unit to determine a sequence in which each optical network unit sends a subsequent uplink optical signal, and send the sequence in the downlink optical to the optical network unit through the signal transmission module;

a reset time determining module, configured to determine the reset time of each optical network unit according to the result of the sorting of the intensities of the uplink optical signals, and send the reset time in downlink light to the optical network units through a signal transmission module; and

and the storage module is used for storing the sequence and the reset time.

12. A method of transmitting an optical signal, comprising:

a first optical network unit sends a first uplink optical signal to an optical line terminal with a first intensity;

the second optical network unit sends a second uplink optical signal to the optical line terminal with a second intensity;

the optical line terminal determines a first sequence number and corresponding first reset time of a third uplink optical signal sent by the first optical network unit by referring to the first intensity and the second intensity;

the optical line terminal determines a second sequence number and corresponding second reset time of a fourth uplink optical signal sent by the second optical network unit by referring to the first intensity and the second intensity;

the optical line terminal sends an instruction to the first optical network unit and the second optical network unit;

the first optical network unit receives the indication and sends the third uplink optical signal to the optical line terminal by referring to the first sequence number and the first reset time;

and the second optical network unit receives the indication and sends the fourth uplink optical signal to the optical line terminal by referring to the second sequence number and the second reset time.

13. A method of transmitting an optical signal, comprising:

a first optical network unit sends a first uplink optical signal to an optical line terminal with a first intensity;

the second optical network unit sends a second uplink optical signal to the optical line terminal with a second intensity;

the optical line terminal determines a first sequence number and corresponding first reset time of a third uplink optical signal sent by the first optical network unit by referring to the first intensity and the second intensity;

the optical line terminal determines a second sequence number and corresponding second reset time of a fourth uplink optical signal sent by the second optical network unit by referring to the first intensity and the second intensity;

the optical line terminal sends a first indication to the first optical network unit by referring to the first sequence number and the first reset time;

the optical line terminal sends a second indication to the second optical network unit by referring to the second sequence number and the second reset time;

the first optical network unit receives the first indication and sends the third uplink optical signal;

and the second optical network unit receives the second indication and sends the fourth uplink optical signal.

14. An optical line terminal comprising a plurality of modules for performing the method of claim 1.

15. An optical line terminal comprising a plurality of modules for performing the method of claim 12.

16. A storage medium storing computer instructions configured to perform the method of claim 1.

17. A storage medium storing computer instructions configured to perform the method of claim 12.

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