WO2017193383A1

WO2017193383A1 - Method and system for transmitting optical signal in passive optical network

Info

Publication number: WO2017193383A1
Application number: PCT/CN2016/082072
Authority: WO
Inventors: 潘志伟; 刘炳森; 魏奇文
Original assignee: 华为技术有限公司
Priority date: 2016-05-13
Filing date: 2016-05-13
Publication date: 2017-11-16
Also published as: CN109155672A; CN109155672B

Abstract

The invention relates to a passive optical network system, and more particularly, relates to signal transmission of an optical line terminal. An optical line terminal sorts uplink beams transmitted by an optical network unit according to intensities, such that a sequence in which the optical network unit transmits the uplink beams and corresponding reset times can be determined, thereby effectively reducing the number of preamble sequences in optical signals, and enabling the optical line terminal to receive more uplink optical signals per unit time.

Description

Method and system for transmitting optical signals by passive optical network

Technical field

Embodiments of the present invention relate to a passive optical network system, and more particularly to signal transmission of an optical line terminal.

Background technique

The main components of the PON (Passive Optical Network) system include an optical line terminal (OLT), an optical network unit (ONU), and an optical splitter that connects 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 PON applications in passive optical networks mainly include: LTE downlink signals adopt continuous broadcast mode, and uplink signals are time division multiple access burst mode. A detailed description of the PON system can be found in the patent documents CN102301670B, CN103248422A, CN103297866B, CN104243092A, or https://en.wikipedia.org/wiki/Passive_optical_network , which is incorporated herein by reference.

For the OLT, the built-in optical module receives the uplink optical of different optical powers. When the optical power difference between the two adjacent uplink opticals is large, the OLT's built-in optical module takes a long time to establish the threshold. Flat, otherwise it will cause a received signal conversion error. An improved approach is to quickly establish a 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 of time.

Summary of the invention

In view of this, the 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 in a unit time.

In a first aspect, embodiments of the present invention provide a method of transmitting optical signals in a passive optical network. The optical line terminal acquires the strength of the uplink optical signal sent by the multiple optical network units. The optical line terminal sorts the strengths of the uplink optical signals to determine the order in which the optical network unit subsequently transmits the uplink optical signals. The optical line terminal determines a reset time corresponding to each optical network unit according to the sorted result. Optical line terminal to optical network unit An indication is sent to cause the optical network unit to transmit a subsequent uplink optical signal to the optical line terminal according to the sequence and the corresponding reset time. By implementing the ordering of the intensity of the uplink optical signals, the implementation manner effectively reduces the difference between the strengths of the different uplink optical signals, thereby reducing the time required for the optical line terminal to be reset, so that the OLT is in unit time. Can receive more upstream optical signals.

In one possible implementation, the above steps may also use other devices without being performed by the optical line terminal.

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

In one possible implementation, the strength of the upstream optical signals may be ordered from small to large, or from large to small. This implementation reduces the voltage fluctuation caused by the fluctuation of the intensity of different upstream optical signals in one cycle, 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 the uplink optical signals in sequential and reverse order in consecutive multiple cycles to further reduce two optical networks between each transmission period. The reset time required by the unit.

In a possible implementation manner, the optical line terminal instructs the optical network unit to determine the preamble sequence length 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 time of resetting the optical line terminal. If the length of the preamble sequence is not enough, the data can not be correctly recognized and converted by the optical line terminal; if the length of the preamble sequence is redundant, the amount of data transmitted in the uplink optical signal is reduced. The optical network unit determines the preamble sequence length of the uplink optical signal according to the corresponding reset time, so that as much valid data is transmitted in the uplink optical signal that is sent once. The length of the preamble sequence in this application is also called the number of preamble bits, that is, the content of the content in the preamble sequence.

In another possible implementation manner, the optical line terminal determines the length of the preamble sequence corresponding to the reset time of the uplink optical signal, and instructs the optical network unit to send the uplink 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 can determine a unified reset time for each optical network unit according to the maximum value of the difference between the two adjacent uplink optical signal strengths. This implementation ensures that the data transmitted by each optical line terminal can be correctly received.

In another possible implementation manner, the optical line terminal may determine a reset time corresponding to each optical network unit according to a difference between the ordered strengths of each two adjacent uplink optical signals. This implementation method 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 obtain the uplink optical signal strength of each optical network unit by detecting. In this implementation manner, the uplink optical signal strength of each optical network unit is acquired in real time and has high accuracy.

In another possible implementation manner, the optical line terminal can read the uplink optical signal strength corresponding to each optical network unit from the storage module. Further, the corresponding relationship between the strength of the uplink optical signal 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 by the outside world. In this implementation, the optical line terminal has the ability to respond quickly, and is easy to install and replace.

In a possible implementation manner, the optical line terminal may periodically detect the received uplink optical signal strength of each optical network unit, and compare with the stored uplink optical signal strength data, when found to be inconsistent or When the optical signal strength of the newly added optical network unit is increased, the uplink optical signal strength is again sorted to determine the sequence and reset time of the optical network unit to send the uplink optical signal.

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

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

Obtaining, by the optical line terminal, a first strength of the first uplink optical signal sent by the first optical network unit;

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

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

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

The optical line terminal sends an indication 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 to send the fourth uplink. The order of the optical signals and the corresponding reset time.

Alternatively, in a possible implementation manner, the optical line terminal determines, in reference to the first strength and the second strength, an order in which the first optical network unit sends the third uplink optical signal, and a corresponding reset time, and the second optical network unit. The order in which the fourth upstream optical signal is transmitted and the corresponding reset time. The two determined steps in the various implementations of the invention can be accomplished in one step.

Alternatively, in a possible implementation manner, the optical line terminal determines, according to the first strength and the second strength, a first sequence number that the first optical network unit sends a third uplink optical signal, and Corresponding first reset time. The optical line terminal determines, according to the first strength and the second strength, a second sequence number that the second optical network unit sends a fourth uplink optical signal and a corresponding second reset time. The sequence number is determined directly 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 indication and transmits a third uplink 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 indication and transmits a 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 determines, according to the first strength and the second strength, a first sequence number that the first optical network unit sends a third uplink optical signal, and a corresponding number. a reset time, and the second optical network unit transmits a second sequence number of the fourth uplink optical signal and a corresponding second reset time.

Alternatively, in a possible implementation manner, the optical line terminal refers to the first cis The sequence number and the first reset time send a first indication to the first optical network unit. 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 termination. The optical line terminal has a function capable of implementing the above method. The functions may be implemented by hardware or by corresponding software implemented by 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:

a signal transmission module, configured to receive an uplink optical signal from the optical network unit, and send the downlink optical to the optical network unit;

a detecting module, configured to detect an uplink optical signal strength sent by the optical network unit received by the optical line terminal;

a sorting module, configured to sort the uplink optical signal strengths sent by each optical network unit to determine an order in which each optical network unit sends the uplink optical signals, and send the sending sequence to the optical network unit in the downlink optical by using the signal transmission module ;

a reset time determining module, configured to determine a reset time of each optical network unit according to a result of sorting the uplink optical signal strength, and send the reset time to the optical network unit in the downlink optical by the signal transmission module; and

A storage module for storing the sequence and reset time.

In a fourth aspect, an embodiment of the present invention provides a passive optical network system that utilizes the optical line and terminal and transmission method of the above implementation manner. Passive optical network systems include optical line terminations, optical splitters, and multiple optical network units. The optical line terminal and the optical network unit are connected by an optical splitter. The optical line terminal has a function capable of realizing the above intelligent sorting. The functions may be implemented by hardware or by corresponding software implemented by 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 passive optical network system includes:

Multiple optical network units;

Optical splitter; and

The optical line terminal is connected to the optical network unit through the optical splitter, and includes:

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

a processor, configured to determine an order of the uplink optical signals by the optical network unit, and a reset time corresponding to each optical network unit, and send the sequence and the reset time to the optical network unit, and

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

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

Through the foregoing solution, the embodiment of the present invention can flexibly identify the uplink optical signal strength, so that the uplink optical signals are sequentially cyclically ordered according to the intensity. In this way, the difference in light intensity between adjacent uplink optical signals can be reduced, the DC voltage threshold is quickly established, and the Preamble preamble sequence bits of each sequence are reduced, so that the OLT can receive more uplink optical signals in a unit time.

DRAWINGS

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

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

3 is a schematic diagram showing changes in a voltage amplitude signal of an optical signal received by an 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 by a passive optical network PON system according to a possible embodiment of the present invention;

FIG. 5 is a schematic diagram showing changes in a voltage amplitude signal of an optical signal received by an optical line terminal OLT according to a possible embodiment of the present invention; FIG.

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

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

FIG. 8 is a block diagram showing a structure of an OLT portion of an optical line terminal according to another possible embodiment of the present invention; FIG.

9 is a flowchart of a method for transmitting an optical signal by 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 by 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 by a passive optical network PON system according to another possible implementation manner of the present invention;

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

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

detailed description

1 is a schematic diagram of a passive optical network PON system provided in accordance with 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 a plurality of ONUs 20. The optical signal transmitted by the ONU 20 to the OLT 10 via the optical splitter 30 is an upstream optical signal, and the optical signal received by the ONU 20 from the OLT 10 via the optical splitter 30 is a downstream optical signal. The plurality of ONUs 20 transmit the uplink light to the OLT 10 in a time division multiple access burst mode, that is, the plurality of ONUs 20 sequentially transmit the uplink light to the OLT 10 in one cycle.

In some places in the present application, "upstream light" is used to refer to "upstream optical signal", and in the case of conformity with the spirit of the invention, it does not hinder the understanding of those skilled in the art.

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

FIG. 2 is a schematic diagram of an optical module receiving circuit of an optical line terminal OLT 10 according to a possible embodiment of the present invention. As shown in FIG. 2, for the OLT 10, when the built-in optical module receives the upstream light of each ONU 20, the built-in optical module is reset at the starting position of the upstream light, so that the storage capacitor C2 is quickly charged and discharged, and the fast setup is achieved. The purpose of the threshold level.

Specifically, when the uplink burst optical signal is received, the current flowing through the PD/APD diode changes proportionally, and the output side of the transconductance amplifier (TIA) correspondingly generates a voltage value corresponding to the light intensity, and the voltage value is given to The capacitor at the LN- pin of the 149CL is charged. Due to the voltage hysteresis characteristic of the capacitor charging, a voltage difference is generated between LN+ and LN-, and the light intensity of the upstream light sent by the same ONU 20 is stable, and the 149CL amplifier can normally reflect the optical signal value. When the difference between the uplink light intensities sent by two adjacent ONUs is large, for example, the second upstream light is smaller than the previous upstream light intensity, and when the second upstream light comes over, the voltage on C2 is higher than that of the LN+ pin. The higher voltage causes amplifier 149CL to incorrectly determine the first few logic 1 signal bits as logic zero. After several upstream optical bits, the discharge of C2 causes the DC threshold to decrease, and the voltage amplifier 149CL can normally output the data of the second upstream light. Similarly, if the two adjacent upstream light intensities are stronger than the first one, charging C2 will be too slow, causing the DC threshold to rise too slowly, resulting in the optical signal of the second ONU 20 being in the first few A bit has a data conversion error.

In order to prevent data conversion errors, the switch switching path can be increased. At the beginning of each sequence, the RESET control mode is used to manually control the M5 and M6 switching devices to be turned on during the switching of different ONUs. Fast discharge of C2 when strong light cuts weak light, or fast charging of C2 when weak light cuts strong light.

Figure 3 reflects the changes in voltage values of LN+ and LN- when weakened by strong light. It can be seen from the voltage of LN- that when the second sequence arrives, the LN-voltage signal will have a slow falling 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 a relatively stable value is reached, at which time the amplifier 149CL can correctly convert the data.

As can be seen from FIG. 3, during the reset process, the ONU 20 can only transmit the preamble sequence Preamble that does not include data. After the reset process ends, the delimiter is used to inform that the data payload Payload/Data needs to be sent next. Therefore, in the case where the data payload Payload/Data does not change in the uplink light transmitted each time, the longer the reset time, the more the ONU 20 needs to transmit more preamble sequences Preamble, and thus a longer transmission time is required. In particular, the larger the difference in adjacent optical power, the longer the reset time is required. In a PON system, an OLT 10 device usually connects dozens of ONU 20 devices at the same time, and the uplink communication uses a time division multiple access burst mode, which requires multiple resets. It can be seen that during the same guard time Guard time, reducing the reset time enables more ONUs 20 to send upstream light.

The embodiment of the invention reduces the reset time, thereby improving the efficiency of the PON system for transmitting optical signals.

4 is a flow chart of a method for transmitting optical signals by a passive optical network PON system according to a possible embodiment of the present invention. As shown in FIG. 4, the method includes the following steps.

Step 100, start.

In step 101, the OLT acquires the uplink light intensity of each ONU.

Errors in the production and installation process, or the use of different types of ONU equipment, or signal attenuation due to the quality and length of the connected cable may cause inconsistencies in the upstream light intensity of each ONU. The OLT obtains the uplink light intensity of each ONU, thereby establishing a correspondence between the uplink light intensity and each ONU.

In a possible implementation manner, after receiving the uplink light of each ONU, the OLT may obtain the uplink light intensity of each ONU by detecting. A variety of methods of detection in the prior art can be incorporated into embodiments of the invention, such as CN100505592C. Further, the OLT can measure the detected light intensity and The correspondence of the ONUs is stored in the storage module. The storage module can be built in the OLT or an external storage device.

In another possible implementation manner, the OLT may read the uplink light intensity corresponding to each ONU from the storage module. Further, the correspondence between the uplink 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 by the outside world.

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

Step 102: The OLT sorts the uplinks by intensity to determine the sending order of the ONUs.

The results of sorting the intensity of the ascending light can be from small to large, from large to small, or from small to large and from large to small. The result of the sort can be reflected in one cycle or in multiple cycles. Loops in multiple cycles can be cycled sequentially or reversed. As shown in FIG. 1 , for example, the uplink light intensity is from ONU 2, ONU 3, and ONU 1, respectively, and the ordering may be ONU 2, ONU 3, ONU 1, that is, the uplink light intensity is sorted from small to large; ONU 1, ONU 3, ONU 2, that is, the uplink light intensity is sorted from large to small; it can also be ONU 2, ONU 3, ONU 1, ONU 2, ONU 3, ONU 1, that is, the ascending light intensity is sorted from small to large. Repeated; can also be ONU 2, ONU 3, ONU 1, ONU 1, ONU 3, ONU 2, that is, the ascending light intensity from small to large and reversed.

In a possible implementation manner, the OLT sorts the intensity of the uplink light and determines the transmission order of the ONUs in two steps.

As shown in FIG. 5, the ONU sends the uplink light to the OLT according to the sorting result of the uplink light intensity, so that the difference between the uplink light intensities sent by the respective ONUs is reduced, thereby shortening the time required for resetting the RESET and causing the ONU to transmit. In the uplink optical signal, the number of bits of the preamble Preamble can be reduced, so that more ONUs send uplink light in a unit time, thereby transmitting more data payload Payload/Data.

In other words, regardless of whether the difference in the intensity of the upstream light is negative, the OLT is reset, so the absolute value of the difference between the reset RESET time and the upstream light intensity is related. When the intensity of the upstream light transmitted by the ONU is arranged according to the intensity, the required reset RESET time is the least when compared with the irregular fluctuation.

For example, assume that the upstream light intensity values of ONU 1, ONU 2, and ONU 3 are 4, 1, and 3, respectively. If the upstream light is not numbered and the number is sent by the number, the difference in light intensity corresponding to the two RESETs between the three upstream lights is 4-1=3 and |1-3|=2, respectively. If the uplink light is transmitted in the order of ONU 2, ONU 3, and ONU 1 according to the sorting result from small to large, the difference in light intensity corresponding to the two RESETs between the three upstream lights is |1-3|=2, respectively. And |3-4|=1, so that the RESET time is shortened. It can be seen that when the number of devices is further increased, the solution for determining the ONU transmission order according to the uplink light intensity according to the embodiment of the present invention can effectively reduce the RESET time, so that the ONU can reduce the transmitted preamble sequence Preamble, thereby making the OLT in 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 uplink light intensity of the ONU.

In a possible implementation manner, the OLT determines a uniform RESET time for each ONU according to the ranking result of the uplink light intensity. Specifically, the OLT determines the RESET time according to the maximum value of the difference between the two adjacent uplink 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 difference in the intensity of the upstream light ensures that the data in the upstream light transmitted by each ONU can be effectively identified and converted, thereby avoiding conversion errors.

In another possible implementation manner, the OLT determines a corresponding RESET time for each ONU according to the ranking result of the uplink light intensity. Specifically, the OLT determines the RESET time of each ONU according to the difference between each of the two adjacent uplink light intensities, and then notifies the RESET time corresponding to each ONU. In other words, the ONU with a lower upstream light intensity than the previous ONU has a shorter RESET time, and the upstream light intensity has a longer RESET time than the ONU with a larger change from the previous ONU. In this implementation In the mode, the ONU can determine the preamble sequence Preamble to be sent according to the actual RESET requirement, so that the OLT can receive more uplink optical signals in a unit time.

In a possible implementation manner, the OLT may store the sort result and the reset RESET time in the storage module. When the OLT is replaced or powered off and then turned back on, it is not necessary to repeat the above steps.

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

Step 104: The OLT instructs the ONU to send the uplink light according to the sorting result and the reset RESET time.

The ONU can determine the length of the preamble sequence Preamble to be transmitted according to the RESET time sent by the OLT, and then send the uplink 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 at the OLT.

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

In a possible implementation, the detection and sequencing of the light intensity may also be performed not by the OLT device, for example, by an optical splitter, or by placing a detection and/or sequencing device between the OLT and the ONU. To be done.

In a possible implementation manner, the OLT may instruct the ONU to send the sequence of the uplink light, or may discharge the transmission time in one cycle or multiple cycles to each ONU device, and then indicate the time for the ONU to send the uplink light. In this embodiment, the ONU determines the length of the preamble sequence Preamble that needs to be transmitted according to the transmission time.

In the embodiment of the present invention, the uplink light intensity sent by the ONU is intelligently detected by the built-in optical module of the OLT in a time division multiple access sequence period, and the uplink sequences of all ONUs are sequentially arranged according to the intensity from large to small. The voltage conditions of LN+ and LN- under this embodiment are shown in FIG. It can be seen that the uplink light sequence sent by multiple ONUs is arranged in sequence according to the light intensity, so that the light intensity difference of adjacent light 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 required bit length of the Preamble sequence can be reduced, and the total time occupied by the corresponding ONU uplink light can be shortened. When the guard time Guard time is unchanged, the OLT can be made Can receive more upstream optical signals per unit time.

In a possible implementation manner, the OLT instructs the ONU to alternately transmit the uplink light in sequential and reverse order in successive cycles to further reduce the RESET time required by the ONU between each transmission period. In this cycle, a plurality of ONU devices sequentially send an uplink light.

Specifically, in order to ensure that there is no excessive difference in light intensity during cyclic switching of each cycle, the uplink optical sequence is cyclically ordered from strong to weak→from weak to strong→from strong to weak according to the period, so that When there is no excessive light intensity difference, the number of bits in the preamble sequence is reduced and the duration is shorter. For example, an example of the 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 switching from the ONU with the strongest light intensity to the sharp change of the ONU with the lowest light intensity is avoided, and the reset time is shortened.

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

When an ONU device is added or replaced, the corresponding upstream light sequence is added, or the light intensity ordering changes. The OLT in this embodiment can automatically detect all the uplink light intensity periodically, so even if such a change occurs, the OLT can re-sequence all the upstream lights according to the predetermined light intensity rule. That is, as shown in FIG. 5, all the upstream lights are sequentially sorted according to the light intensity.

Specifically, the OLT may periodically compare the received uplink optical strength of each ONU with the data in the storage module, and if the inconsistency or the newly added ONU uplink optical strength is found, the ONU device is again sorted and determined. Reset time.

In another possible implementation manner, the OLT can also compare the received uplink optical intensity of each ONU with the data in the storage module in real time. When an inconsistent or newly added ONU uplink light intensity is found, The ONU device sorts again and determines the reset time.

FIG. 6 is a schematic structural diagram of a passive optical network PON system according to a possible implementation manner of the present invention. As shown in FIG. 6, the OLT 10 is connected to a plurality of ONUs 20 via 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 uplink light transmitted from the ONU 20 and transmit the downlink light to the ONU 20.

The processor 12 is configured to determine the order of the uplink 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 to store the result of the processor 12 sorting the ONU 20 according to the transmitted upstream light intensity and the reset time corresponding to each ONU 20.

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

FIG. 7 is a block diagram showing a structure of an OLT portion of an optical line terminal according to a possible embodiment of the present invention. As shown in FIG. 7, the OLT includes a signal transmission module 14, a detection module 15, a sequencing module 16, a reset time determination module 17, and a storage module 18.

The signal transmission module 14 is configured to receive the uplink light from the ONU and send the downlink light to the ONU.

The detecting module 15 is configured to detect the uplink light intensity sent by the ONU received by the OLT.

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

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

The storage module 18 is configured to store the sort result of the sorting module 16 and the reset time determined by the reset time determining module 17.

In one possible implementation, the ranking module 16 ranks the intensity of the ascending light according to the size from small to large, or from large to small.

In a possible implementation manner, the ordering module 16 instructs the optical network unit ONU to alternately transmit the uplink light in sequential and reverse order in successive multiple cycles.

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

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

In a possible implementation manner, the reset time determining module 17 determines a uniform reset time for each optical network unit ONU according to the maximum value of the difference between the strengths of the two adjacent uplink lights that are sorted.

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

In a possible implementation manner, the detecting module 15 stores the detected intensity of the uplink light of each of the optical network units ONUs into the storage module 18.

In a possible implementation manner, the detecting module 15 periodically detects the received uplink light intensity of each optical network unit ONU, and compares with the stored uplink light intensity data, when found to be inconsistent or When added, the sorting module 16 sorts the intensity of the upstream light again to determine the order in which the optical network unit ONU transmits the upstream light, and the reset time determining module 17 determines the reset time.

In a possible implementation manner, the detecting module 15 detects the received uplink light intensity of each optical network unit ONU in real time, and compares it with the stored uplink light intensity data, when found to be inconsistent or new In the incrementing manner, the sorting module 16 sorts the intensity of the upstream light again to determine the order in which the optical network unit ONU transmits the upstream light, and the reset time determining module 17 determines the reset time.

FIG. 8 is a block diagram showing a structure of an OLT portion of an optical line terminal according to another possible embodiment of the present invention. As shown in FIG. 8, different from the embodiment shown in FIG. 7, the embodiment further includes a sending sequence determining module 19, configured to determine, according to the result of sorting by the sorting module 16, an order in which the ONU sends subsequent uplink lights, and The sequence is transmitted to the ONU in the downstream light by the signal transmission module 14.

9 is a flow chart of a method for transmitting optical signals by a passive optical network PON system according to a possible embodiment of the present invention. As shown in FIG. 9, after the OLT sorts the uplink optical signal strengths of the ONU 1 and the ONU 2, the transmission sequence and the reset time are determined, and the transmission sequence and the reset time are sent to the ONU, indicating that the ONU 1 transmits the second uplink optical signal, and the ONU 2 The first one sends an upstream optical signal.

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

11 is a flow chart of a method for transmitting optical signals by a passive optical network PON system according to still another possible implementation of the present invention. As shown in FIG. 11, after sorting the uplink optical signal strengths of the ONU 1 and the ONU 2, the OLT determines the transmission sequence number and the reset time, and sends a transmission sequence number and a reset time to the ONU, instructing the ONU 1 to send the second uplink optical signal. The ONU 2 first transmits an upstream optical signal.

12 is a flow chart of a method of transmitting an optical signal by a passive optical network PON system according to still another possible implementation of the present invention. As shown in FIG. 12, after the OLT sorts the uplink optical signal strengths of the ONU 1 and the ONU 2, the transmission sequence and the reset time are determined, and the transmission time is sent to the ONU, indicating that the ONU 1 transmits the second uplink optical signal, and the ONU 2 is first. One sends an upstream optical signal.

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

In one possible implementation, the ONU and/or optical splitter may also have an architecture as shown in FIG.

Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented in hardware, firmware implementation, or a combination thereof. When implemented in software, the functions described above may be stored in or transmitted 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 location to another. A storage medium may be any available media that can be accessed by a computer. By way of example and not limitation, the computer readable medium can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage media or other magnetic storage device, or can be used for carrying or storing an instruction or data structure. The desired program code and any other medium that can be accessed by a computer. Also. Any connection may suitably be 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 fixing of the associated media. As used in the present invention, a disk and a disc include a compact disc (CD), a laser disc, a compact disc, a digital versatile disc (DVD), a floppy disk, and a Blu-ray disc, wherein the disc is usually magnetically copied, and the disc is The laser is used to optically replicate the data. Combinations of the above should also be included within the scope of the computer readable media.

In summary, the above description is only a preferred embodiment of the technical solution of the present invention, and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

A method of transmitting an optical signal, comprising:

Obtaining, by the optical line terminal, a first strength of the first uplink optical signal sent by the first optical network unit;

Obtaining, by the optical line terminal, a second strength of the second uplink optical signal sent by the second optical network unit, where the second strength is not equal to the first strength;

Determining, by the optical line terminal, the sequence of sending the third uplink optical signal by the first optical network unit and the corresponding reset time by using the first strength and the second strength;

Determining, by the optical line terminal, the sequence of sending the fourth uplink optical signal by the second optical network unit and the corresponding reset time by using the first strength and the second strength;

The optical line terminal sends an indication 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, The second optical network unit learns the sequence of transmitting the fourth uplink optical signal and the corresponding reset time.
The method of claim 1 wherein said optical line termination orders said first intensity and said second intensity in descending order, or from largest to smallest.
The method of claim 2, wherein the order in which the first optical network unit transmits the third uplink optical signal and the sequence in which the second optical network unit transmits the fourth upstream optical signal are continuous The uplink optical signal is alternately transmitted in a plurality of cycles.
A method according to any one of claims 1 to 3, further comprising the optical line terminal instructing the first optical network unit and the second optical network unit to determine the first according to the corresponding reset time a length of the first preamble sequence of the three uplink optical signals and a second preamble sequence length of the fourth uplink optical signal.
The method of any of claims 1-3, further comprising the optical line terminal determining that the third uplink optical signal corresponds to a first preamble sequence length and the fourth uplink of the corresponding reset time The optical signal corresponds to a length of the second preamble sequence of the corresponding reset time, and the optical line terminal instructs the first optical network unit and the second optical network unit to be according to the length of the first preamble sequence And transmitting, by the length of the second preamble sequence, the third uplink optical signal and the fourth uplink optical signal to the optical line terminal.
The method of any of claims 1-5, wherein the first intensity and the second intensity are obtained by the optical line terminal by detection.
The method of any of claims 1-5, wherein the first intensity and the second intensity are read by the optical line terminal from a memory module.
The method of claim 7, further comprising the optical line terminal periodically detecting the received third intensity of the third upstream optical signal and the fourth strength of the fourth upstream optical signal, and The stored first intensity and the second intensity are compared. When an inconsistency or an increase is found, the optical line terminal determines the first by referring to the third strength and the fourth strength. The sequence of the fifth uplink optical signal sent by the optical network unit and the corresponding reset time, wherein the optical line terminal determines the sequence of sending the sixth uplink optical signal by the second optical network unit by referring to the third strength and the fourth strength And the corresponding reset time.
The method of claim 7, further comprising the optical line terminal detecting the third strength of the received third uplink optical signal and the fourth strength of the fourth upstream optical signal in real time, and The stored first intensity and the second intensity are compared. When an inconsistency or an increase is found, the optical line terminal determines the first light by referring to the third intensity and the fourth intensity. a sequence in which the network unit sends a fifth uplink optical signal, and a corresponding reset time, where the optical line terminal determines, in the third strength and the fourth strength, an order in which the second optical network unit sends the sixth uplink optical signal, and The corresponding reset time.
A passive optical network system comprising:

Multiple optical network units;

Optical splitter; and

The optical line terminal is connected to the multiple optical network units by using the optical splitter, and includes:

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

a processor, configured to determine an order of strengths of the uplink optical signals to determine a sequence in which the plurality of optical network units transmit subsequent uplink optical signals, and a reset time corresponding to the multiple optical network units, and the sequence and the The reset time is sent to the plurality of optical network units, and

a memory for storing the sequence and the reset time corresponding to the plurality of optical network units;

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.
An optical line terminal comprising:

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

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

a sorting module, configured to sort the strengths of the uplink optical signals sent by each of the optical network units to determine an order in which each of the optical network units sends a subsequent uplink optical signal, and use the signal transmission module to The sequence is sent to the optical network unit in the downlink light;

a reset time determining module, configured to determine, according to a result of the intensity ranking of the uplink optical signal, a reset time of each of the optical network units, and send, by using a signal transmission module, a reset time in the downlink optical to the optical network unit; and

a storage module for storing the sequence and the reset time.
A method of transmitting an optical signal, comprising:

The first optical network unit sends the first uplink optical signal to the optical line terminal with the first strength;

The first optical network unit sends a second uplink optical signal to the optical line terminal with a second strength;

Determining, by the optical line terminal, the first sequence number of the third uplink optical signal and the corresponding first reset time by using the first strength and the second strength;

Determining, by the optical line terminal, the second sequence number of the fourth uplink optical signal and the corresponding second reset time by using the first strength and the second strength;

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 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;

The second optical network unit receives the indication, and sends the fourth uplink optical signal to the optical line terminal with reference to the second sequence number and the second reset time.
A method of transmitting an optical signal, comprising:

The first optical network unit sends the first uplink optical signal to the optical line terminal with the first strength;

The first optical network unit sends a second uplink optical signal to the optical line terminal with a second strength;

Determining, by the optical line terminal, the first sequence number of the third uplink optical signal and the corresponding first reset time by using the first strength and the second strength;

Determining, by the optical line terminal, the second sequence number of the fourth uplink optical signal and the corresponding second reset time by using the first strength and the second strength;

Transmitting, by the optical line terminal, the first indication to the first optical network unit by using the first sequence number and the first reset time;

Transmitting, by the optical line terminal, the second indication to the second optical network unit by using the second sequence number and the second reset time;

Receiving, by the first optical network unit, the first indication, and sending the third uplink optical signal;

The second optical network unit receives the second indication, and sends the fourth uplink optical signal.
An optical line termination comprising a plurality of modules for performing the method of claim 1.
An optical line termination comprising a plurality of modules for performing the method of claim 12.
A computer program product configured to perform the method of claim 1.
A computer program product configured to perform the method of claim 12.