CN105577265B

CN105577265B - Calibration method of uplink wavelength channel of passive optical network system and optical network unit

Info

Publication number: CN105577265B
Application number: CN201410555256.9A
Authority: CN
Inventors: 耿丹; 张德智; 张伟良
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2014-10-17
Filing date: 2014-10-17
Publication date: 2020-04-24
Anticipated expiration: 2034-10-17
Also published as: CN105577265A

Abstract

The invention discloses a method for calibrating an uplink wavelength channel of a passive optical network system and an optical network unit, wherein the method for calibrating the uplink wavelength of the PON system comprises the following steps: and the optical network unit ONU calibrates the uplink wavelength channels according to the sequence of the correlation values of the uplink wavelength channels and/or the uplink wavelength channels, wherein the sequence is the sequence from large to small or from small to large according to the correlation values of the uplink wavelength channels and/or the uplink wavelength channels. By the invention, the calibration of the uplink wavelength is realized.

Description

Calibration method of uplink wavelength channel of passive optical network system and optical network unit

Technical Field

The present invention relates to the field of communications, and in particular, to a method for calibrating an uplink wavelength channel of a Passive Optical Network (PON) system and an optical network unit.

Background

With the development of network technology, a large amount of services such as voice, data, video and the like can be transmitted by using a network, so that the requirement for bandwidth is continuously increased, and a PON is generated under the requirement. As shown in fig. 1, a topology structure of a PON system generally includes an Optical Line Terminal (OLT) on an office side, an Optical Network Unit (ONU) on a user side, and an Optical Distribution Network (ODN), and generally adopts a point-to-multipoint Network structure. The ODN is composed of a single-mode optical fiber, and passive optical devices such as an optical splitter and an optical connector, and provides an optical transmission medium for physical connection between the OLT and the ONU. In order to further increase the bandwidth of the network, a PON system that transmits multiple wavelengths in a trunk fiber and provides access by using a Time Division technique on each wavelength is called a Time Wavelength Division Multiplexing (TWDM) PON system.

As shown in fig. 2, a topology structure of the TWDM PON system is that a plurality of TWDM Channel terminals (CTs for short) are provided in the TWDM PON OLT, each TWDM CT processes a pair of associated upper and lower wavelength channels (forming a TWDM Channel), and provides access and maintenance services for all ONUs operating in the pair of wavelength channels. The ONU transmits data in the pair of wavelength channels by time division multiplexing. The uplink and downlink wavelength channels processed by different TWDM CTs are different. Each ONU transmits upstream data in a specific upstream time slot according to the instruction of the OLT CT.

For reasons of load balancing, energy saving, and reduction of the inventory types of ONUs, the ONUs in the TWDM PON system are colorless, that is, all the ONUs have the same transmitter and receiver in physical structure, and the transmission wavelength and the reception wavelength of the ONUs are set to be tunable. The ONU can tune the operating wavelength of the device to operate in the upstream and downstream wavelength channels of any OLTCT. Because the wavelength value of the OLT CT in different networks is not fixed, the ONU devices are unified, the cost of the ONU is reduced, and the ONU does not set a fixed operating wavelength when leaving the factory, that is, does not perform wavelength calibration. In order to ensure that the ONU can accurately tune to the uplink wavelength and the downlink wavelength in the TWDM channel corresponding to each CT of the OLT to work when the ONU works in an actual network, when the ONU is connected to the PON system, the ONU needs to complete the wavelength calibration work with the assistance of the OLT CT. This process is called online calibration. There is an on-line calibration procedure for both the downstream and upstream wavelengths.

In the on-line calibration process of the upstream wavelength of the ONU, the ONU mainly sends corresponding detection signals at each wavelength position in a tunable range of the ONU by adjusting a transmitter, and tries to acquire the feedback of the OLT CT. Therefore, whether the current wavelength position of the emission detection signal is the uplink wavelength channel of one OLT CT is determined. If the feedback of the OLT CT is obtained, the feedback can be recorded to finish the uplink wavelength calibration of the OLT CT. If the uplink wavelength calibration of all the OLT CTs is to be completed, the above process needs to be repeated several times until the completion. In the development process of the technology, two technologies are developed aiming at different transmission methods of the ONU detection signals.

The first method utilizes a static window in O3 state in the ONU registration activation state machine in the XGPON where a properly functioning ONU will not send upstream data for the period of the static window. Therefore, the detection signal can be sent on the premise of not interfering the conventional normal ONU, and the detection signal is prevented from being submerged in the data transmission signal. Because the ONU cannot determine the upstream wavelength of which OLT CT it belongs to when transmitting the probe signal, in order to avoid the influence on data transmission of all OLT CTs, all CTs of the OLT need to open completely synchronized static windows with the same length, so that the interference of transmitting upstream data on any upstream channel to other upstream data completing wavelength calibration of the ONU during ONU upstream wavelength calibration can be avoided. The method has no extra requirements on the device capability of the ONU, but puts higher requirements on different CTs of the OLT: firstly, when all TWDM synchronization open quiet windows, the whole TWDM PON system cannot send uplink service data, which may affect the transmission efficiency of uplink data, and all TWDM synchronization open quiet windows also require all TWDM channels to implement strict time synchronization, which increases the complexity of the system and increases the probability of abnormal ONUs. Another disadvantage is that it is difficult to communicate bandwidth allocation policies between different operators if different OLT CTs are subordinate to different operators.

The second method is to modulate the low frequency part of the detection signal arranged in the same wavelength point to transmit the low speed detection signal, thereby avoiding the intermediate frequency and high frequency parts of the data transmission, and indirectly avoiding the disadvantage of using a static window. However, the second method also brings about a great disadvantage, mainly in the PON network, in order to make the probing signal not cause crosstalk to the data signal, the sending power of the probing signal is pressed to be very low, thereby greatly improving the capability of the OLT receiver, and it is difficult to realize and implement industrial production in technology. And if the ONU uses a low frequency to transmit data, additional low frequency filtering and modulation devices are required, which also increases the cost.

In summary, both methods introduce new problems that are difficult to solve or overcome while solving the problem of on-line calibration of the upstream wavelength. Whether a new or improved method can be proposed based on the above two methods, which is an ongoing research subject in the industry, while solving the problem of on-line calibration of the upstream wavelength and reducing the cost or complexity of new introduction.

Disclosure of Invention

The invention provides a calibration method of an uplink wavelength channel of a PON system and an Optical Network Unit (ONU) aiming at the problem of online calibration of the uplink wavelength of the ONU in the PON system, so as to at least solve the problem.

According to an aspect of the present invention, there is provided a method for calibrating an upstream wavelength of a PON system, including: and the optical network unit ONU calibrates the uplink wavelength channels according to the sequence of the correlation values of the uplink wavelength channels and/or the uplink wavelength channels, wherein the sequence is the sequence from large to small or from small to large according to the correlation values of the uplink wavelength channels and/or the uplink wavelength channels.

Preferably, the ONU calibrates the upstream wavelength channels according to the sequence of the correlation values of the upstream wavelength channels and/or the upstream wavelength channels, and the calibration includes: the ONU acquires at least one first signal in at least one TWDM channel in the PON system, wherein the first signal indicates the sequence of the uplink wavelength channel through the carried uplink wavelength value of the TWDM channel and/or the relevant value of the uplink wavelength channel; and the ONU selects the uplink wavelength channels according to the sequence of the uplink wavelength channels for calibration.

Preferably, the calibration of the upstream wavelength channel by the ONU includes: the ONU determines an initial position for calibrating the selected uplink wavelength channel; and the ONU starts to calibrate the selected uplink wavelength channel from the initial position.

Preferably, the determining, by the ONU, the start position of the calibration on the selected upstream wavelength channel includes one of: when the ONU does not have a calibrated uplink wavelength channel, the ONU selects the maximum wavelength or the minimum wavelength in a tuning range supported by the ONU as the initial position; and when the ONU has the calibrated uplink wavelength channel, the ONU determines the initial position according to the calibrated uplink wavelength channel.

Preferably, the calibration of the upstream wavelength channel by the ONU includes: the ONU acquires resource information which can be used for calibration in a TWDM channel where an uplink wavelength channel is located; the ONU transmits a second signal based on the resource information from the determined starting position; and the ONU calibrates the selected uplink wavelength channel according to the response of whether the second signal is received.

Preferably, the ONU calibrates the selected upstream wavelength channel according to whether the response of the second signal is received, where the calibrating includes one of: when the response is not received under the preset condition, the ONU adjusts the wavelength for sending the second signal according to the preset step length, and sends the second signal based on the resource information at the adjusted wavelength position; when the response is received under the preset condition, the ONU records the wavelength position of the second signal as the calibration information of the uplink wavelength channel, adjusts the wavelength position according to a preset step length and sends the second signal based on the resource information; and after receiving the signal which indicates the conflict and is sent by the TWDM channel terminal, the ONU sends the second signal again on the basis of the resource information at the existing wavelength position.

Preferably, the method further comprises the following steps: and the ONU suspends or continues wavelength calibration after receiving a command sent by the TWDM channel.

Preferably, the ONU adjusts the wavelength for transmitting the second signal according to a preset step size, which includes at least one of: if the starting position is greater than the currently calibrated wavelength, the adjustment is to increase the wavelength; if the starting position is less than the currently calibrated wavelength, the adjustment is to decrease the wavelength; when the starting position selects the maximum wavelength in the tuning range supported by the ONU, the wavelength is adjusted to be reduced; when the starting position selects the minimum wavelength in the self-supported tuning range for the ONU, the adjustment is to increase the wavelength.

Preferably, the method further comprises the following steps: and after recording the calibration information, the ONU adjusts the wavelength position according to a preset step length and sends the second signal based on the resource information.

Preferably, the method further comprises the following steps: the ONU records the position of the uplink sending wavelength when the response is received for the first time as the minimum wavelength value of the uplink wavelength; and the ONU records the uplink sending wavelength position corresponding to the response received for the last time as the maximum wavelength value of the uplink wavelength.

Preferably, the method further comprises the following steps: and determining that the uplink wavelength position of the maximum or optimal position of the received power indicated in the response is the middle wavelength value of the uplink wavelength in the period from the first time of receiving the response to the last time of receiving the response.

Preferably, the preset conditions include: a predetermined time and/or a predetermined number of retransmissions; wherein if a response to the second signal is not received within a predetermined time after the second signal is transmitted, it is determined that the response is not received; or if the response is not received within the predetermined time, retransmitting the second signal until the response is received or the number of retransmissions is greater than the predetermined number of retransmissions.

Preferably, the information carried by the response includes at least one of: the current uplink wavelength channel identifier, the identifier of the TWDM channel that sends the response, the current uplink wavelength value, the received power information of the second signal, and the received power change information of the second signal.

Preferably, the determining, by the ONU, the start position according to the calibrated upstream wavelength channel includes: the ONU determines the initial position of the currently calibrated uplink wavelength channel according to the optimal uplink wavelength position of the calibrated uplink wavelength channel and the interval value between the uplink wavelength channels; when the initial position is larger than the calibrated uplink wavelength channel, moving to increase the uplink wavelength according to the interval value; when the starting position is smaller than the calibrated upstream wavelength channel, the shifting is to decrease the upstream wavelength according to the interval value.

According to another aspect of the present invention, there is also provided a method for calibrating an upstream wavelength of a passive optical network PON system, the method including: the optical line terminal OLT sends at least one first signal on a time division wavelength division multiplexing (TWDM) channel, wherein the first signal indicates the sequence of the upper wavelength channel through the carried uplink wavelength channel and/or uplink wavelength channel correlation value of the TWDM channel, and the sequence is ordered from large to small or from small to large according to the wavelength and/or uplink wavelength channel correlation value.

Preferably, the optical line terminal OLT sends uplink resource information for uplink wavelength channel calibration on the TWDM channel.

Preferably, the method further comprises the following steps: the OLT receives a second signal which is sent by at least one ONU and used for calibrating an uplink wavelength channel, wherein the second signal carries an identifier or related information of the ONU sending the second signal; the OLT sends a response of the second signal to the at least one ONU, wherein the information carried in the response comprises at least one of the following: the channel identification of the current uplink wavelength, the channel identification of the current TWDM, the wavelength value of the current uplink wavelength channel, the receiving power information of the receiver and the receiving power change information of the receiver.

Preferably, the method further comprises the following steps: and after the OLT detects a second conflicting signal in an upstream resource for upstream wavelength channel calibration, the OLT notifies the ONU of detecting a third conflicting signal.

Preferably, the method further comprises the following steps: after receiving the second signal, the OLT increases the set frequency of the uplink resource; and/or the OLT slows down the set frequency of the uplink resource after not receiving the second signal.

According to another aspect of the present invention, there is provided an optical network unit ONU comprising: and the calibration device is used for calibrating the uplink wavelength channels according to the sequence of the correlation values of the uplink wavelength channels and/or the uplink wavelength channels, wherein the sequence is the sequence from large to small or from small to large according to the correlation values of the uplink wavelength channels and/or the uplink wavelength channels.

Preferably, the calibration device comprises: an obtaining module, configured to obtain at least one first signal in at least one TWDM channel in a PON system, where the first signal indicates an order of uplink wavelength channels by using an uplink wavelength value of the carried TWDM channel and/or a correlation value of the uplink wavelength channel; and the calibration module is used for selecting the uplink wavelength channels according to the sequence of the uplink wavelength channels for calibration.

Preferably, the calibration module comprises: a determining unit, configured to determine an initial position for calibrating the selected uplink wavelength channel; and the calibration unit is used for calibrating the selected uplink wavelength channel from the initial position.

Preferably, the determining unit determines the starting position for calibrating the selected uplink wavelength channel, where the starting position includes one of: when the calibrated uplink wavelength channel does not exist, selecting the maximum wavelength or the minimum wavelength in the tuning range supported by the self as the starting position; and when the calibrated uplink wavelength channel exists, determining the starting position according to the calibrated uplink wavelength channel.

According to another aspect of the present invention, there is also provided an optical line termination, OLT, comprising: a first sending module, configured to send at least one first signal on a time division wavelength division multiplexing TWDM channel, where the first signal indicates an order of upper wavelength channels through an upper wavelength channel and/or an upper wavelength channel correlation value of the carried TWDM channel, where the order is a sequence according to wavelengths and/or upper wavelength channel correlation values from large to small or from small to large.

Preferably, the first sending module is further configured to send uplink resource information for uplink wavelength channel calibration on the TWDM channel.

Preferably, the method further comprises the following steps: the receiving module is configured to receive a second signal for uplink wavelength channel calibration, where the second signal carries an identifier or related information of an ONU that sends the second signal, and the ONU is configured to send the second signal to the receiving module; a second sending module, configured to send a response to the second signal to the at least one ONU, where information carried in the response includes at least one of: the channel identification of the current uplink wavelength, the channel identification of the current TWDM, the wavelength value of the current uplink wavelength channel, the receiving power information of the receiver and the receiving power change information of the receiver.

Preferably, the method further comprises the following steps: and the notification module is used for notifying the OLT of detecting a third conflicting signal by the ONU after detecting the second conflicting signal in an upstream resource for upstream wavelength channel calibration.

Preferably, the method further comprises the following steps: an increasing module, configured to increase a set frequency of the uplink resource after receiving the second signal; and/or a reducing module, configured to slow down a set frequency of the uplink resource after the second signal is not received.

By the invention, the ONU carries out the uplink wavelength calibration according to the sequence of the uplink wavelength and/or the uplink wavelength related value range, can improve the uplink transmission efficiency of the PON system, reduce the clock synchronization precision between all TWDM and channels of the OLT in the TWDM PON system, reduce the complexity of the OLT and improve the network service quality.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

fig. 1 is a structural diagram of a PON system according to the related art;

fig. 2 is a topology structural diagram of a TWDM PON system according to the related art;

fig. 3 is a first flowchart of a calibration method for an upstream wavelength channel of a PON system according to an embodiment of the present invention;

fig. 4 is a block diagram of a structure of an optical network unit ONU according to an embodiment of the present invention;

fig. 5 is a second flowchart of a calibration method for an upstream wavelength channel of a PON system according to an embodiment of the present invention;

figure 6 is a block diagram of the architecture of an optical line termination OLT according to an embodiment of the present invention;

fig. 7 is a first flowchart illustrating an upstream wavelength calibration method for a PON according to a preferred embodiment of the present invention;

fig. 8 is a second flowchart illustrating an uplink wavelength calibration method for a PON according to a preferred embodiment of the present invention;

fig. 9 is a third flowchart illustrating an uplink wavelength calibration method for a PON according to a preferred embodiment of the present invention; and

fig. 10 is a fourth flowchart illustrating an uplink wavelength calibration method for a PON according to a preferred embodiment of the present invention.

Detailed Description

The invention will be described in detail hereinafter with reference to the accompanying drawings in conjunction with embodiments. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

In the following embodiments, reference is made to the system architecture shown in fig. 1 and 2, but without being limited thereto. It is contemplated that the following embodiments may be implemented by a computer program element, which may be stored in a memory and executed by a processor.

The embodiment of the invention provides a method for calibrating an uplink wavelength of a PON system, wherein the PON system comprises a plurality of TWDM channels, each TWDM has an uplink wavelength range and a downlink wavelength range, the uplink wavelength range of each TWDM channel is different, and one or more ONUs are used for carrying out uplink transmission in the uplink wavelength range of each TWDM channel.

Fig. 3 is a first flowchart of a calibration method for an upstream wavelength channel of a PON system according to an embodiment of the present invention, as shown in fig. 3, the method includes step S302:

step S302, the optical network unit ONU calibrates the uplink wavelength channels according to the sequence of the correlation values of the uplink wavelength channels and/or the uplink wavelength channels, where the sequence is sorted from large to small or from small to large according to the correlation values of the uplink wavelength channels and/or the uplink wavelength channels.

In an implementation manner of the embodiment of the present invention, in the step S302, the ONU may monitor at least one first signal in at least one TWDM channel of the plurality of TWDM channels, where the first signal indicates an order of the uplink wavelength channels by using an uplink wavelength value of the carried TWDM channel and/or a correlation value of the uplink wavelength channel; and the ONU selects the uplink wavelength channels according to the sequence of the uplink wavelength channels for calibration.

In an implementation manner of the embodiment of the present invention, the calibrating, by the ONU, the upstream wavelength channel may include:

step A, the ONU determines an initial position for calibrating the selected uplink wavelength channel;

and step B, the ONU starts to calibrate the selected uplink wavelength channel from the initial position.

The ONU determines the initial position of the selected uplink wavelength channel for calibration, and the initial position comprises one of the following positions: when the ONU does not have a calibrated uplink wavelength channel, the ONU selects the maximum wavelength or the minimum wavelength in a tuning range supported by the ONU as an initial position; and when the ONU has the calibrated uplink wavelength channel, the ONU determines the initial position according to the calibrated uplink wavelength channel.

step C, the ONU acquires resource information which can be used for calibration in a TWDM channel where an uplink wavelength channel is located;

d, the ONU starts from the determined initial position and sends a second signal based on the resource information;

and E, the ONU selects the obtained uplink wavelength channel according to the response calibration of whether the second signal is received.

The ONU calibrates the selected uplink wavelength channel according to whether the response of the second signal is received, and the uplink wavelength channel comprises one of the following components: when the response is not received under the preset condition, the ONU adjusts the wavelength for sending the second signal according to the preset step length, and sends the second signal on the adjusted wavelength position based on the resource information; when the response is received under the preset condition, the ONU records the wavelength position of the second signal as the calibration information of the uplink wavelength channel, adjusts the wavelength position according to the preset step length and sends the second signal based on the resource information; and after receiving the signal which indicates the conflict and is sent by the TWDM channel terminal, the ONU sends a second signal again on the basis of the resource information at the existing wavelength position.

In one implementation manner of the embodiment of the present invention, the ONU suspends or continues the wavelength calibration after receiving the command sent by the TWDM channel.

The ONU adjusts the wavelength of the second signal according to the preset step length, and the wavelength at least comprises one of the following steps: if the initial position is larger than the currently calibrated wavelength, adjusting to increase the wavelength; if the initial position is smaller than the currently calibrated wavelength, adjusting to reduce the wavelength; when the initial position selects the maximum wavelength in the tuning range supported by the ONU for the ONU, the wavelength is adjusted to be reduced; when the start position selects the minimum wavelength in the tuning range supported by the ONU for the ONU, the wavelength is adjusted to be increased.

In an implementation manner of the embodiment of the present invention, after recording the calibration information, the ONU adjusts the wavelength position according to a preset step size and transmits the second signal based on the resource information.

Preferably, the ONU records the position of the upstream transmission wavelength at the time of receiving the response for the first time as the minimum wavelength value of the upstream wavelength; and the ONU records the uplink sending wavelength position corresponding to the response received for the last time as the maximum wavelength value of the uplink wavelength.

Preferably, the uplink wavelength position at which the received power indicated in the response is the maximum or the optimum position is determined to be the intermediate wavelength value of the uplink wavelength in the period from the first reception of the response to the last reception of the response.

The preset conditions include: a predetermined time and/or a predetermined number of retransmissions; wherein if a response to the second signal is not received within a predetermined time after the second signal is transmitted, it is determined that the response is not received; or if no response is received within a predetermined time, retransmitting the second signal until a response is received or the number of retransmissions is greater than a predetermined number of retransmissions.

Preferably, the information carried by the response includes at least one of: the current uplink wavelength channel identifier, the identifier of the TWDM channel sending the response, the current uplink wavelength value, the received power information of the second signal, and the received power change information of the second signal.

Preferably, the determining, by the ONU, the start position according to the calibrated upstream wavelength channel includes: the ONU determines the initial position of the currently calibrated uplink wavelength channel according to the optimal uplink wavelength position of the calibrated uplink wavelength channel and the interval value between the uplink wavelength channels; when the initial position is larger than the calibrated uplink wavelength channel, moving to increase the uplink wavelength according to the interval value; when the starting position is less than the calibrated upstream wavelength channel, the shift is to decrease the upstream wavelength by the interval value.

An embodiment of the present invention further provides an optical network unit ONU, where the ONU is located in a PON system, where the PON system includes a plurality of TWDM channels, each TWDM has an uplink wavelength range and a downlink wavelength range, the uplink wavelength range of each TWDM channel is different, and one or more ONUs are configured to perform uplink transmission in the uplink wavelength range of each TWDM channel.

Fig. 4 is a block diagram of a structure of an optical network unit ONU according to an embodiment of the present invention, and as shown in fig. 4, the ONU includes: and the calibration device 42 is configured to calibrate the uplink wavelength channels according to the sequence of the correlation values of the uplink wavelength channels and/or the uplink wavelength channels, where the sequence is sorted from large to small or from small to large according to the correlation values of the uplink wavelength channels and/or the uplink wavelength channels.

In one implementation of the embodiment of the present invention, the calibration device 42 includes:

the system comprises an obtaining module, a receiving module and a processing module, wherein the obtaining module is used for obtaining at least one first signal in at least one TWDM channel in the PON system, and the first signal indicates the sequence of the uplink wavelength channel through the carried uplink wavelength value of the TWDM channel and/or the correlation value of the uplink wavelength channel;

and the calibration module is used for selecting the uplink wavelength channels according to the sequence of the uplink wavelength channels for calibration.

Wherein, calibration module includes: a determining unit, configured to determine an initial position for calibrating the selected uplink wavelength channel; and the calibration unit is used for calibrating the selected uplink wavelength channel from the initial position.

The determining unit determines that the initial position for calibrating the selected uplink wavelength channel comprises one of the following:

when the calibrated uplink wavelength channel does not exist, selecting the maximum wavelength or the minimum wavelength in the tuning range supported by the self as the initial position;

and when the calibrated uplink wavelength channel exists, determining the starting position according to the calibrated uplink wavelength channel.

In an implementation manner of the embodiment of the present invention, the calibration module is configured to perform the following processes:

(1) transmitting a second signal for uplink wavelength calibration by using the selected uplink resource of the TWDM from a wavelength closest to a currently calibrated wavelength among the currently uncalibrated wavelengths;

(2) judging whether the response of the second signal is received;

(3) when the response is received under the preset condition, recording the wavelength for sending the second signal as the wavelength of the selected TWDM channel, adjusting the wavelength for sending the second signal according to a preset step length, and sending the second signal on the adjusted wavelength by using the uplink resource of the selected TWDM;

(4) and when the response is not received under the preset condition, adjusting the wavelength for transmitting the second signal according to the preset step length, and transmitting the second signal on the adjusted wavelength by using the selected uplink resource of the TWDM.

Further, the above apparatus may further include: a determining module, configured to determine that a wavelength indicated in the response with a maximum received power is an intermediate wavelength of the selected TWDM channel during a period from a first time of receiving the response to a last time of receiving the response.

For other parts which are the same as the above method, refer to the description of the above-mentioned method, and are not described again here.

Corresponding to the above method and ONU, an embodiment of the present invention further provides a method for calibrating an uplink wavelength of a PON system, where the PON system includes a plurality of TWDM channels, each TWDM has an uplink wavelength range and a downlink wavelength range, the uplink wavelength range of each TWDM channel is different, and one or more ONUs are configured to perform uplink transmission in the uplink wavelength range of each TWDM channel.

Fig. 5 is a second flowchart of a calibration method for an upstream wavelength channel of a PON system according to an embodiment of the present invention, as shown in fig. 4, the method includes step S502:

step S502: the optical line terminal OLT sends at least one first signal on a time division wavelength division multiplexing (TWDM) channel, wherein the first signal indicates the sequence of the upper wavelength channel through the carried uplink wavelength channel and/or uplink wavelength channel correlation value of the TWDM channel, and the sequence is ordered according to the wavelength and/or uplink wavelength channel correlation value from large to small or from small to large.

Optionally, the optical line termination OLT sends uplink resource information for uplink wavelength channel calibration on the TWDM channel.

In another implementation manner of the embodiment of the present invention, the method may further include:

step F: the OLT receives a second signal which is sent by at least one ONU and used for calibrating the uplink wavelength channel, wherein the second signal carries an identifier or related information of the ONU sending the second signal;

step G: the OLT sends a response of the second signal to at least one ONU, wherein the information carried in the response comprises at least one of the following: the channel identification of the current uplink wavelength, the channel identification of the current TWDM, the wavelength value of the current uplink wavelength channel, the receiving power information of the receiver and the receiving power change information of the receiver.

Step H: after the OLT detects the second signal of the conflict in the upstream resource for the calibration of the upstream wavelength channel, the OLT informs the ONU of detecting the third signal of the conflict

Step I: after receiving the second signal, the OLT increases the setting frequency of the uplink resource; and/or the OLT slows down the set frequency of the uplink resource after not receiving the second signal.

The embodiment of the invention also provides an OLT for an uplink wavelength of a PON system, wherein the PON system comprises a plurality of time division wavelength division multiplexing (TWDM) channels, each TWDM has an uplink wavelength range and a downlink wavelength range, the uplink wavelength range of each TWDM channel is different, and one or more ONUs are used for performing uplink transmission within the uplink wavelength range of each TWDM channel.

Fig. 6 is a block diagram of an optical line terminal OLT according to an embodiment of the present invention, and as shown in fig. 6, the OLT may include: a first sending module 62, configured to send at least one first signal on a time division wavelength division multiplexing TWDM channel, where the first signal indicates an order of upper wavelength channels through uplink wavelength channels and/or uplink wavelength channel correlation values of the carried TWDM channels, where the order is in an order from a wavelength and/or uplink wavelength channel correlation value to a small value or from a small value to a large value.

In this embodiment of the present invention, the first sending module is further configured to send uplink resource information for uplink wavelength channel calibration on the TWDM channel.

In an implementation manner of the embodiment of the present invention, the method may further include:

the receiving module is used for receiving a second signal which is sent by at least one ONU and used for calibrating the uplink wavelength channel, wherein the second signal carries an identifier or related information of the ONU sending the second signal;

a second sending module, configured to send a response to the second signal to at least one ONU, where information carried in the response includes at least one of: the method comprises the steps that a current uplink wavelength channel identifier, a current TWDM channel identifier, a current uplink wavelength channel wavelength value, receiving power information of a receiver and receiving power change information of the receiver are obtained;

the OLT notifies the ONU of detecting a third conflicting signal after detecting a second conflicting signal in an upstream resource for upstream wavelength channel calibration;

an increasing module, configured to increase a setting frequency of the uplink resource after receiving the second signal; and/or a reducing module, configured to slow down a set frequency of the uplink resource after the second signal is not received.

For other parts which are the same as the above method, refer to the description of the method shown in fig. 5, and are not described again here.

By the embodiment of the invention, the ONU carries out the uplink wavelength calibration according to the sequence of the uplink wavelength range, thereby improving the uplink transmission efficiency of the PON system, reducing the clock synchronization precision between all TWDM and channels of the OLT in the TWDM PON system, reducing the complexity of the OLT and improving the network service quality.

In order to facilitate understanding of the embodiments of the present invention, a plurality of embodiments are described as examples below. In the embodiments of the present invention, various implementations of the embodiments of the present invention may be combined without conflict.

In the following embodiments, a "static window" is described and explained as an example of the "uplink resource" according to the embodiment of the present invention.

Implementation mode one

The TWDM PON system is provided with a plurality of TWDM channels, each TWDM channel corresponds to one TWDM channel terminal and one group of ONU, each TWDM channel corresponds to one downlink wavelength channel and corresponds to one or a plurality of uplink wavelength channels. Different TWDM channels correspond to different downlink wavelength channels and different uplink wavelength channels. And the OLT commands each ONU connected to the PON system to work on a TWDM channel, and the ONU receives downlink data by using a downlink wavelength channel corresponding to the TWDM channel and sends uplink data by using an uplink wavelength channel corresponding to the TWDM channel. After the ONU is powered on, if the ONU does not have a downlink wavelength calibration record, the ONU tunes the own receiving wavelength from low to high or from high to low, and if the ONU receives a downlink signal, the ONU stores the corresponding relation between the tuning parameter of the own receiving wavelength and the downlink wavelength value or the current TWDM channel or the current downlink wavelength identifier, thereby completing the calibration of the current downlink wavelength. And when the ONU finishes the calibration of all the downlink wavelengths, the ONU starts the calibration of the uplink wavelength channel. The OLT and the ONU adopt the following key steps to carry out the uplink wavelength calibration of the ONU. The TWDM channel identifier is proportional to the uplink wavelength value, and the uplink wavelength identifier is proportional to the uplink wavelength value.

Fig. 7 is a first flowchart illustrating a method for calibrating an upstream wavelength of a PON according to a preferred embodiment of the present invention, as shown in fig. 7, including steps S702 to S712.

Step S702: when the OLT opens a quiet window for upstream wavelength calibration for the ONU on part or all of the TWDM channels, at least one of the following channel-related information is carried in the upstream bandwidth allocation corresponding to the quiet window: current uplink wavelength identification, current TWDM channel identification and current uplink wavelength value.

Step S704: if the ONU does not finish the uplink wavelength calibration of the channel, the ONU calibrates wavelength channels one by one from the shortest wavelength to the longest wavelength according to the wavelength range that the ONU can tune, determines whether the uplink wavelength calibration of the TWDM channel corresponding to all TWDM channel related information values smaller than the TWDM channel related information value that is not finished is finished, if so, executes step S706, and if not, executes step S708.

Step S706: the ONU transmits the calibration signal in the quiet window corresponding to the upstream bandwidth for wavelength calibration transmitted by the OLT, and then executes step S710.

Step S708: the ONU does not respond to the uplink bandwidth for wavelength calibration sent by the OLT, and returns to continue to execute step S704 until all the uplink wavelength calibrations of the TWDM channels corresponding to the TWDM channel related information values that have been completed and are smaller than the wavelength calibration uncompleted value are completed.

In a preferred embodiment of the present invention, the ONU starts sending the calibration signal at the shortest wavelength within the wavelength range that the ONU can tune itself, and after the ONU sends the wavelength calibration signal, if the ONU does not receive the reply of the OLT, the ONU continues sending the calibration signal after receiving the upstream bandwidth allocation for wavelength calibration sent by the OLT of the channel, and if the ONU sends the calibration signal N times on the upstream wavelength, the ONU tunes its own transmission wavelength to a longer wavelength corresponding to the next step length, and continues sending the calibration signal after receiving the upstream bandwidth allocation for wavelength calibration sent by the OLT of the channel.

Step S710: sending at least one of the following upstream channel related information to the ONU: current uplink wavelength identification, current TWDM channel identification and current uplink wavelength value.

Step S712: and the ONU stores the corresponding relation between the tuning parameter of the sending wavelength and the uplink wavelength value or the current TWDM channel or the current uplink wavelength identifier of the ONU so as to finish the calibration of the current uplink wavelength.

Preferably, after completing the uplink wavelength calibration of the first TWDM channel according to the above steps, after receiving the bandwidth allocation for the uplink wavelength calibration on the second TWDM channel, the ONU tunes its own transmission wavelength to a wavelength value corresponding to a step length larger than the uplink wavelength value corresponding to the first TWDM channel, and then sends an uplink calibration signal to perform the uplink wavelength calibration of the second TWDM channel, and the OLT and the ONU repeat the above steps, and the ONU completes the uplink wavelength calibration of all uplink channels.

In the embodiment of the present invention, preferably, when the ONU performs calibration one by one on the TWDM channels in the wavelength range that can be tuned by itself from the shortest wavelength to the longest wavelength, when the ONU completes calibration on the TWDM channel corresponding to the short wavelength, the TWDM channel terminal corresponding to the short wavelength notifies the TWDM channel terminal corresponding to the adjacent long wavelength channel that the ONU needs to perform calibration.

In the embodiment of the present invention, preferably, when a newly added TWDM channel in the TWDM PON system requires the ONU to perform wavelength calibration, the ONU starts wavelength tuning from a boundary value of a wavelength value range corresponding to an adjacent channel of the newly added TWDM channel toward a wavelength direction of the newly added TWDM channel, and sends a calibration signal to perform wavelength calibration.

Preferably, the step value of the ONU tuning the upstream wavelength may be a value corresponding to 1/N of the TWDM upstream channel interval.

Second embodiment

Fig. 8 is a second flowchart illustrating a method for calibrating an upstream wavelength of a PON according to a preferred embodiment of the present invention, and as shown in fig. 8, the method includes steps S802 to S812.

Step S802: when the OLT opens a quiet window for upstream wavelength calibration for the ONU on part or all of the TWDM channels, at least one of the following channel-related information is carried in the upstream bandwidth allocation corresponding to the quiet window: current uplink wavelength identification, current TWDM channel identification and current uplink wavelength value.

Preferably, the uplink bandwidth allocation further carries at least one of the following: all uplink wavelength identifiers, all TWDM channel identifiers, all uplink wavelength values.

Step S804: after receiving uplink bandwidth allocation for wavelength calibration sent by an OLT (optical line terminal), if the ONU does not finish the uplink wavelength calibration of the channel, the ONU calibrates wavelength channels one by one from the shortest wavelength to the longest wavelength according to the wavelength range which can be tuned by the ONU, and determines whether the uplink wavelength calibration of all TWDM channels is finished or not, wherein the related information value of the TWDM channels is smaller than that of the TWDM channels corresponding to the related information value of the wavelength calibration-unfinished TWDM channels; step S806 is performed if it has been completed, and step S808 is performed if it has not been completed.

Step S806: the ONU transmits the calibration signal in the quiet window corresponding to the upstream bandwidth for wavelength calibration transmitted by the OLT, and then executes step S810.

Step S808: the ONU does not respond to the uplink bandwidth for wavelength calibration sent by the OLT, and returns to continue to execute step S804 until all the uplink wavelength calibrations of the TWDM channels corresponding to the TWDM channel related information values that have been completed and are smaller than the wavelength calibration uncompleted value are completed.

In the preferred embodiment of the present invention, preferably, the ONU starts sending the calibration signal at the shortest wavelength within the wavelength range that the ONU can tune, after the ONU sends the wavelength calibration signal, if the ONU does not receive the reply of the OLT, the ONU continues sending the calibration signal after receiving the upstream bandwidth allocation for wavelength calibration sent by the OLT of the channel, and if the ONU sends the calibration signal N times on the upstream wavelength, and does not receive the reply of the OLT, the ONU tunes its own transmission wavelength to a longer wavelength, and continues sending the calibration signal after receiving the upstream bandwidth allocation for wavelength calibration sent by the OLT of the channel.

Step S810: sending at least one of the following upstream channel related information to the ONU: current uplink wavelength identification, current TWDM channel identification and current uplink wavelength value.

Step S812: and the ONU stores the corresponding relation between the tuning parameter of the sending wavelength and the uplink wavelength value or the current TWDM channel or the current uplink wavelength identifier of the ONU so as to finish the calibration of the current uplink wavelength.

In the preferred embodiment of the present invention, preferably, when the ONU performs calibration one by one on the TWDM channels from the shortest wavelength to the longest wavelength according to the wavelength range that the ONU can tune, when the ONU completes calibration on the TWDM channel corresponding to the short wavelength, the TWDM channel terminal corresponding to the short wavelength notifies the TWDM channel terminal corresponding to the adjacent long wavelength channel that the ONU needs to perform calibration.

In the preferred embodiment of the present invention, preferably, when a newly added TWDM channel in the TWDM PON system requires the ONU to perform wavelength calibration, the ONU starts wavelength tuning from a boundary value of a wavelength value range corresponding to an adjacent channel of the newly added TWDM channel toward a wavelength direction of the newly added TWDM channel, and sends a calibration signal to perform wavelength calibration.

In the preferred embodiment of the present invention, preferably, the step value of the ONU tuning uplink wavelength may be a value corresponding to 1/N of the TWDM uplink channel interval.

Third embodiment

Fig. 9 is a third schematic flowchart of an upstream wavelength calibration method for a PON according to a preferred embodiment of the present invention, and as shown in fig. 9, the flowchart includes the following steps:

step S902: when the OLT opens a quiet window for upstream wavelength calibration for the ONU on part or all of the TWDM channels, at least one of the following channel-related information is carried in the upstream bandwidth allocation corresponding to the quiet window: current uplink wavelength identification, current TWDM channel identification and current uplink wavelength value.

Preferably, at least one of the following is also carried in the uplink bandwidth allocation: all uplink wavelength identifiers, all TWDM channel identifiers, all uplink wavelength values.

Step S904: after receiving uplink bandwidth allocation for wavelength calibration sent by an OLT (optical line terminal), if the ONU does not finish uplink wavelength calibration of the channel and the ONU calibrates wavelength channels one by one from the longest wavelength to the shortest wavelength according to the wavelength range which can be tuned by the ONU, determining whether the uplink wavelength calibration of all TWDM channels is finished or not, wherein the TWDM channels corresponding to the TWDM channel related information values which are not finished are larger than the TWDM channels corresponding to the TWDM channels which are not finished; if it has been completed, step S906 is performed, and if it has not been completed, step 908 is performed.

In step S906, the ONU transmits the calibration signal in the quiet window corresponding to the upstream bandwidth for wavelength calibration, which is transmitted by the OLT, and then executes step S910.

Step S908, the ONU does not respond to the uplink bandwidth for wavelength calibration sent by the OLT, and returns to continue to execute step S904 until all the uplink wavelength calibrations of the TWDM channels whose TWDM channel related information values have been completed are smaller than the uplink wavelength calibrations of the TWDM channels corresponding to the wavelength calibration uncompleted TWDM channel related information values.

In the preferred embodiment of the present invention, preferably, the ONU starts sending the calibration signal at the longest wavelength within the wavelength range that the ONU can tune, after the ONU sends the wavelength calibration signal, if the ONU does not receive the reply of the OLT, the ONU continues sending the calibration signal after receiving the upstream bandwidth allocation for wavelength calibration sent by the OLT of the channel, and if the ONU sends the calibration signal N times on the upstream wavelength, the ONU tunes the own transmission wavelength to the shorter wavelength corresponding to the next step length, and continues sending the calibration signal after receiving the upstream bandwidth allocation for wavelength calibration sent by the OLT of the channel.

Step S910: sending at least one of the following upstream channel related information to the ONU: current uplink wavelength identification, current TWDM channel identification and current uplink wavelength value.

Step S912: and the ONU stores the corresponding relation between the tuning parameter of the sending wavelength and the uplink wavelength value or the current TWDM channel or the current uplink wavelength identifier of the ONU so as to finish the calibration of the current uplink wavelength.

And after the ONU completes the uplink wavelength calibration of the TWDM channel corresponding to the maximum uplink wavelength value according to the steps, after receiving the bandwidth allocation of the uplink wavelength calibration on the adjacent TWDM channel, the ONU tunes the own emission wavelength to the wavelength value corresponding to one step length which is less than the uplink wavelength value corresponding to the TWDM channel, then sends an uplink calibration signal, and performs the uplink wavelength calibration of the next TWDM channel, and the OLT and the ONU repeat the steps, so that the ONU completes the uplink wavelength calibration of all uplink channels.

In this preferred embodiment, preferably, when the ONU performs calibration one by one on the TWDM channels in the wavelength range that can be tuned by itself from the shortest wavelength to the longest wavelength, when the ONU completes calibration on the TWDM channel corresponding to the short wavelength, the TWDM channel terminal corresponding to the short wavelength notifies the TWDM channel terminal corresponding to the adjacent long wavelength channel that the ONU needs to perform calibration.

In this preferred embodiment, preferably, when a newly added TWDM channel in the TWDM PON system requires the ONU to perform wavelength calibration, the ONU starts wavelength tuning from a boundary value of a wavelength value range corresponding to an adjacent channel of the newly added TWDM channel toward the wavelength direction of the newly added TWDM channel, and sends a calibration signal to perform wavelength calibration.

Embodiment IV

Fig. 10 is a fourth flowchart illustrating a method for calibrating an upstream wavelength of a PON according to a preferred embodiment of the present invention, as shown in fig. 10, including steps S1002 to S1014.

Step S1002: when the OLT opens a quiet window for upstream wavelength calibration for the ONU on part or all of the TWDM channels, at least one of the following channel-related information is carried in the upstream bandwidth allocation corresponding to the quiet window: current uplink wavelength identification, current TWDM channel identification and current uplink wavelength value.

Preferably, at least one of the following contents may also be carried in the uplink bandwidth allocation: all uplink wavelength identifiers, all TWDM channel identifiers, all uplink wavelength values.

Step S1004: after receiving the uplink bandwidth allocation for wavelength calibration sent by the OLT, if the ONU does not complete the uplink wavelength calibration of the channel and the ONU calibrates wavelength channels one by one from the shortest wavelength to the longest wavelength according to the wavelength range that can be tuned by itself, it is determined whether the uplink wavelength calibration of all TWDM channels has been completed for which the TWDM channel related information value is smaller than the TWDM channel corresponding to the wavelength calibration-incomplete TWDM channel related information value, if so, step S1006 is executed, and if not, step S1008 is executed.

Step S1006: the ONU transmits the calibration signal in the quiet window corresponding to the upstream bandwidth for wavelength calibration transmitted by the OLT, and then executes step S1010.

Step S1008: the ONU does not respond to the uplink bandwidth for wavelength calibration sent by the OLT, and returns to continue to execute step S1004 until all the uplink wavelength calibrations of the TWDM channels corresponding to the TWDM channel related information values that have been completed and are smaller than the wavelength calibration uncompleted value are completed.

Step S1010: determining whether an uplink data collision is detected, if no collision is detected, executing step S1012, and if a collision is detected, executing step S1002.

Step S1012: sending at least one of the following upstream channel related information to the ONU: the OLT commands all the ONUs in wavelength calibration of the current TWDM channel to tune the emission wavelength to the uplink wavelength value corresponding to the next step length. After the OLT receives all calibration signals sent by the ONUs on the channel and detects no upstream data collision, the OLT commands all ONUs in wavelength calibration of the current TWDM channel to tune the transmission wavelength to the upstream wavelength value corresponding to the next step length, and step S1012 is executed.

Step S1014: and the ONU stores the corresponding relation between the tuning parameter of the sending wavelength and the uplink wavelength value or the current TWDM channel or the current uplink wavelength identifier of the ONU so as to finish the calibration of the current uplink wavelength. And if the ONU receives the wavelength tuning command of the OLT, the ONU tunes the emission wavelength to the uplink wavelength value corresponding to the next step length.

After completing the uplink wavelength calibration of the first TWDM channel according to the steps, the ONU tunes the receiving wavelength to the next TWDM channel, after receiving the bandwidth allocation of the uplink wavelength calibration on the second TWDM channel, if the ONU does not complete the uplink wavelength calibration of the channel and the ONU calibrates wavelength channels one by one from the shortest wavelength to the longest wavelength according to the wavelength range which can be tuned by the ONU, the ONU determines whether the uplink wavelength calibration of all TWDM channel related information values is smaller than the TWDM channel corresponding to the wavelength calibration-unfinished TWDM channel related information value, if so, the ONU tunes the own transmitting wavelength to the wavelength value which is larger than the uplink wavelength value corresponding to one step length of the uplink wavelength value corresponding to the first TWDM channel and then transmits an uplink calibration signal to perform the uplink wavelength calibration of the second TWDM channel; if not, ONU does not respond to the upstream bandwidth for wavelength calibration sent by OLT, ONU tunes the downstream wavelength to the next TWDM channel. And the OLT and the ONU repeat the steps until the ONU finishes the uplink wavelength calibration of all the uplink channels. The step value of the ONU tuning upstream wavelength can be a value corresponding to 1/N of the TWDM upstream channel interval.

Preferably, the upstream wavelength and the downstream wavelength in all the above preferred embodiments may be the same or different.

From the above description, it can be seen that the present invention achieves the following technical effects: the method and the device have the advantages that the wavelength calibration is carried out according to the OLT command ONU according to the wavelength sequence, the uplink transmission efficiency of the whole PON system can be improved, the precision of clock synchronization among all TWDM channels of the OLT in the TWDM PON system is reduced, the complexity of the OLT is reduced, and the network service quality is improved.

Fifth embodiment

The TWDM PON system is provided with 5 TWDM channels, each TWDM channel corresponds to one TWDM channel terminal and one group of ONU, each TWDM channel corresponds to one downlink wavelength channel and one or more uplink wavelength channels. Different TWDM channels correspond to different downlink wavelength channels and different uplink wavelength channels. Wherein the ONU does not have an upstream wavelength calibration record for any TWDM channel.

Step 1: the OLT sends a static window for upstream wavelength calibration corresponding to its channel itself on each TWDM channel;

step 2: the OLT sends the sequence information of the upstream wavelength channel downstream through a PLOAM message (Profile). The sequence information may take many forms.

Octet	Content
		1-2	ONU identification (broadcast)
3	Type of message (Profile)
		4	Serial number
5	CH1(λu1)<Logical numbering, from small to large
		6	CH1(λu2)<Logical numbering, from small to large
7	CH1(λu3)<Logical numbering, from small to large
		8	CH1(λu4)<Logical numbering, from small to large
9	CH1(λu5)<Logical numbering, from small to large
		10～40	Reserved bit (or complement 0)

Or

And step 3: the ONU receives the information in step 2, and knows that no calibration information for all upstream wavelength channels is currently available from the existing wavelength calibration information, and determines to perform calibration from CH1(λ u 1). Adjusting a receiver to a λ d1 channel corresponding to λ u1, and receiving static window information for λ u1 sent by the OLT in step 1;

and 4, step 4: the ONU adjusts the transmitter to the minimum end of the wavelength tuning range as the wavelength detection position,

and 5: repeatedly sending PLOAM message SN _ ONU responding to the static window, wherein the SN _ ONU message contains ONU identification information SN (or other ID capable of marking identity, etc.) and/or indication of calibration detection message, and target upstream wavelength channel identification (or frequency) aimed at by the detection message, and starting a timer T1 when sending for the first time;

step 6: if the timer T1 does not receive the response message fed back by the OLT before the timeout, increasing the detected wavelength position by S, and repeating the step 5 at the new position until the response message fed back by the OLT is received;

and 7: the ONU receives the response message sent by the OLT for the first time in the λ d1 channel, where the wavelength detection position is λ u1L, for example, as follows:

Octet	Content
		1-2	ONU identification (broadcast)
3	Type of message (Profile)
		4	Serial number
5	ONUID (optional) corresponding to received probe signal
		6	Current ascending channel mark (optional)
7	Frequency of currently received probe signal (optional)

8	The power of the currently received sounding signal (optional)

Recording the lambda u1L as the minimum wavelength boundary of the current detection channel lambda u 1;

and 8: continuing to increase S every time for the λ u1L in the step 7 until the ONU cannot receive a response message returned by the OLT, and setting λ u1R as the maximum wavelength boundary of the minimum wavelength channel for the wavelength detection position one step before the corresponding wavelength detection position;

and step 9: recording the wavelength range of [ λ u1L, λ u1R ] as the calibration wavelength range of the uplink wavelength channel λ u 1;

sixth embodiment

Or

and 7: in the detection process after each wavelength increase of the ONU, in a λ d1 channel, starting from a wavelength detection position corresponding to when the OLT first receives a response message returned by the OLT, until a wavelength detection position at which the OLT cannot receive the response message returned by the OLT after the timer T1 times out, a detailed message returned by a plurality of OLTs will be received, for example, as follows:

Octet	Content
		1-2	ONU identification (broadcast)
3	Type of message (Profile)
		4	Serial number
5	ONUID (optional) corresponding to received probe signal
		6	Current ascending channel mark (optional)
7	Frequency of currently received probe signal (optional)
		8	The power of the currently received probe signal (optional)

Determining a wavelength detection position lambdau 1C corresponding to the maximum receiving power as a central wavelength point of a minimum wavelength channel according to the receiver power information indicated in the response message returned by the OLT;

seventh embodiment

Or

And step 3: the ONU receives the information in step 2, and knows that no calibration information for all upstream wavelength channels is currently available from the existing wavelength calibration information, and determines to perform calibration from CH1(λ u 5). Adjusting a receiver to a λ d5 channel corresponding to λ u5, and receiving static window information for λ u5 sent by the OLT in step 1;

and 4, step 4: the ONU adjusts the transmitter to the maximum end of the wavelength tuning range as the wavelength detection position,

step 6: if the timer T1 does not receive the response message fed back by the OLT before the timeout, reducing the detected wavelength position by S, and repeating the step 5 at the new position until the response message fed back by the OLT is received;

and 7: the ONU receives the response message sent by the OLT for the first time in the λ d1 channel, where the wavelength detection position is λ u5R, for example, as follows:

Octet	Content
		1-2	ONU identification (broadcast)
3	Type of message (Profile)
		4	Serial number
5	ONUID (optional) corresponding to received probe signal
		6	Current ascending channel mark (optional)
7	Frequency of currently received probe signal (optional)
		8	The power of the currently received sounding signal (optional)

Recording the lambda u5R as the maximum wavelength boundary of the current detection channel lambda u 5;

and 8: continuing to reduce the λ u5R in the step 7 by S each time until the ONU cannot receive a response message returned by the OLT, and setting λ u5L for the wavelength detection position one step before the corresponding wavelength detection position, which is the minimum wavelength boundary of the maximum wavelength channel;

and step 9: recording the wavelength range of [ λ u5L, λ u5R ] as the calibration wavelength range of the uplink wavelength channel λ u 1;

embodiment eight

Or

and 7: the ONU repeatedly decreases the wavelength again and detects the wavelength, and receives detailed messages returned by a plurality of OLTs from the wavelength detection position corresponding to the time when the λ d5 channel receives the OLT return response message for the first time to the wavelength detection position at which the OLT return response message cannot be received after the timer T1 times out, for example, the following steps are performed:

Octet	Content
		1-2	ONU identification (broadcast)
3	Type of message (Profile)
		4	Serial number
5	Correspond toUpon receipt of a probe signal ONUID (optional)
		6	Current ascending channel mark (optional)
7	Frequency of currently received probe signal (optional)
		8	The power of the currently received probe signal (optional)

Determining a wavelength detection position lambdau 5C corresponding to the maximum receiving power as a central wavelength point of a minimum wavelength channel according to the receiver power information indicated in the response message returned by the OLT;

ninth embodiment

The TWDM PON system is provided with 5 TWDM channels, each TWDM channel corresponds to one TWDM channel terminal and one group of ONU, each TWDM channel corresponds to one downlink wavelength channel and one or more uplink wavelength channels. Different TWDM channels correspond to different downlink wavelength channels and different uplink wavelength channels. The ONU has an upstream wavelength calibration record of lambdau 3.

Or

And step 3: the ONU receives the information in step 2, obtains the calibration information of the existing λ u3 from the existing wavelength calibration information, and determines to start calibration on the neighboring CH2(λ u 2). Adjusting a receiver to a λ d2 channel corresponding to λ u2, and receiving static window information for λ u2 sent by the OLT in step 1;

and 4, step 4: the ONU takes the wavelength minimum boundary range lambda u3L + T indicated in the calibration information of lambda u3 of the transmitter as the initial detection wavelength position, or the central wavelength point lambda u3C-CS/2 indicated in the calibration information of lambda u3 as the initial detection wavelength position; wherein T is an integer multiple of the minimum tuning step length of the ONU, and T < CS/2; wherein CS is the wavelength difference between different upstream wavelength channels; the purpose is to move the detection start position for λ u2 out of the wavelength range of λ u3 without falling into λ u 2.

and 7: the ONU receives the response message sent by the OLT for the first time in the λ d2 channel, where the wavelength detection position is λ u2R, for example, as follows:

Recording the lambda u2R as the maximum wavelength boundary of the current detection channel lambda u 2;

and 8: continuing to reduce S of the λ u2R in the step 7 every time and continuing to detect until the ONU cannot receive a response message returned by the OLT, and setting the wavelength detection position of the step before the corresponding wavelength detection position as the minimum wavelength boundary of λ u2 by using λ u 2L;

and step 9: recording the wavelength range of [ λ u2L, λ u2R ] as the calibration wavelength range of the uplink wavelength channel λ u 2;

step 7-9 may be replaced by another method according to step 7 in the sixth embodiment, which is not described herein again.

Detailed description of the preferred embodiment

Or

And step 3: the ONU receives the information in step 2, obtains the calibration information of the existing λ u3 from the existing wavelength calibration information, and determines to start calibration on the neighboring CH2(λ u 4). Adjusting a receiver to a λ d4 channel corresponding to λ u4, and receiving static window information for λ u4 sent by the OLT in step 1;

and 4, step 4: the ONU takes the wavelength maximum boundary range lambda u4L + T indicated in the calibration information of lambda u3 of the transmitter as the initial detection wavelength position, or the central wavelength point lambda u3C + CS/2 indicated in the calibration information of lambda u4 as the initial detection wavelength position; wherein T is an integer multiple of the minimum tuning step length of the ONU, and T < CS/2; wherein CS is the wavelength difference between different upstream wavelength channels; the purpose is to move the detection start position for λ u4 out of the wavelength range of λ u3 without falling into λ u 4.

and 7: the ONU receives the response message sent by the OLT for the first time in the λ d4 channel, where the wavelength detection position is λ u4L, for example, as follows:

Recording the lambda u4L as the minimum wavelength boundary of the current detection channel lambda u 4;

and 8: continuing to increase S and detect the λ u2L in the step 7 successively until the ONU cannot receive a response message returned by the OLT, and setting λ u4R as a maximum wavelength boundary of λ u4 for the wavelength detection position one step before the corresponding wavelength detection position;

and step 9: recording the wavelength range of [ λ u4L, λ u4R ] as the calibration wavelength range of the uplink wavelength channel λ u 4;

From the above description, it can be seen that the present invention achieves the following technical effects: the ONU carries out uplink wavelength calibration according to the sequence of the uplink wavelength range, can improve the uplink transmission efficiency of the PON system, reduce the clock synchronization precision between all TWDM and channels of the OLT in the TWDM PON system, reduce the complexity of the OLT and improve the network service quality.

It will be apparent to those skilled in the art that the modules or steps of the present invention described above may be implemented by a general purpose computing device, they may be centralized on a single computing device or distributed across a network of multiple computing devices, and alternatively, they may be implemented by program code executable by a computing device, such that they may be stored in a storage device and executed by a computing device, and in some cases, the steps shown or described may be performed in an order different than that described herein, or they may be separately fabricated into individual integrated circuit modules, or multiple ones of them may be fabricated into a single integrated circuit module. Thus, the present invention is not limited to any specific combination of hardware and software.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for calibrating an upstream wavelength channel of a Passive Optical Network (PON) system, the method comprising:

and the optical network unit ONU calibrates the uplink wavelength channels according to the sequence of the correlation values of the uplink wavelength channels and/or the uplink wavelength channels, wherein the sequence is the sequence from large to small or from small to large according to the correlation values of the uplink wavelength channels and/or the uplink wavelength channels.

2. The method according to claim 1, wherein the ONU calibrating the upstream wavelength channel according to the order of the correlation values of the upstream wavelength channel and/or the upstream wavelength channel comprises:

the ONU acquires at least one first signal in at least one TWDM channel in the PON system, wherein the first signal indicates the sequence of the uplink wavelength channel through the carried uplink wavelength value of the TWDM channel and/or the relevant value of the uplink wavelength channel;

and the ONU selects the uplink wavelength channels according to the sequence of the uplink wavelength channels for calibration.

3. The method of claim 2, wherein the ONU calibrating the upstream wavelength channel comprises:

the ONU determines an initial position for calibrating the selected uplink wavelength channel;

and the ONU starts to calibrate the selected uplink wavelength channel from the initial position.

4. The method according to claim 3, wherein the ONU determines a starting position of the selected upstream wavelength channel for calibration, and comprises one of:

when the ONU does not have a calibrated uplink wavelength channel, the ONU selects the maximum wavelength or the minimum wavelength in a tuning range supported by the ONU as the initial position;

and when the ONU has the calibrated uplink wavelength channel, the ONU determines the initial position according to the calibrated uplink wavelength channel.

5. The method according to any of claims 2 to 4, wherein the ONU calibrating the upstream wavelength channel comprises:

the ONU acquires resource information which can be used for calibration in a TWDM channel where an uplink wavelength channel is located;

the ONU transmits a second signal based on the resource information from the determined starting position;

and the ONU calibrates the selected uplink wavelength channel according to the response of whether the second signal is received.

6. The method of claim 5, wherein the ONU calibrating the selected upstream wavelength channel according to whether the response of the second signal is received comprises one of:

when the response is not received under the preset condition, the ONU adjusts the wavelength for sending the second signal according to the preset step length, and sends the second signal based on the resource information at the adjusted wavelength position;

when the response is received under the preset condition, the ONU records the wavelength position of the second signal as the calibration information of the uplink wavelength channel, adjusts the wavelength position according to a preset step length and sends the second signal based on the resource information;

and after receiving the signal which indicates the conflict and is sent by the TWDM channel terminal, the ONU sends the second signal again on the basis of the resource information at the existing wavelength position.

7. The method of any of claims 1 to 4, further comprising:

and the ONU suspends or continues wavelength calibration after receiving a command sent by the TWDM channel.

8. The method of claim 5, further comprising:

9. The method of claim 6, further comprising:

10. The method of claim 6, wherein the ONU adjusts the wavelength for transmitting the second signal according to a preset step size, and comprises at least one of:

if the starting position is greater than the currently calibrated wavelength, the adjustment is to increase the wavelength;

if the starting position is less than the currently calibrated wavelength, the adjustment is to decrease the wavelength;

when the starting position selects the maximum wavelength in the tuning range supported by the ONU, the wavelength is adjusted to be reduced;

when the starting position selects the minimum wavelength in the self-supported tuning range for the ONU, the adjustment is to increase the wavelength.

11. The method of claim 5, further comprising:

and after recording the calibration information, the ONU adjusts the wavelength position according to a preset step length and sends the second signal based on the resource information.

12. The method of claim 11, further comprising:

the ONU records the position of the uplink sending wavelength when the response is received for the first time as the minimum wavelength value of the uplink wavelength;

and the ONU records the uplink sending wavelength position corresponding to the response received for the last time as the maximum wavelength value of the uplink wavelength.

13. The method of claim 11, further comprising:

and determining that the uplink wavelength position of the maximum or optimal position of the received power indicated in the response is the middle wavelength value of the uplink wavelength in the period from the first time of receiving the response to the last time of receiving the response.

14. The method according to any one of claims 6, 9 and 10, wherein the preset conditions include: a predetermined time and/or a predetermined number of retransmissions; wherein the content of the first and second substances,

determining that the response is not received if the response to the second signal is not received within a predetermined time after the second signal is transmitted; or

If the response is not received within the predetermined time, retransmitting the second signal until the response is received or the number of retransmissions is greater than the predetermined number of retransmissions.

15. The method of claim 5, wherein the information carried by the response includes at least one of:

the current uplink wavelength channel identifier, the identifier of the TWDM channel that sends the response, the current uplink wavelength value, the received power information of the second signal, and the received power change information of the second signal.

16. The method according to any one of claims 6, 8 and 9, wherein the information carried by the response comprises at least one of:

17. The method of claim 4, wherein the ONU determining the start position according to the calibrated upstream wavelength channel comprises:

the ONU determines the initial position of the currently calibrated uplink wavelength channel according to the optimal uplink wavelength position of the calibrated uplink wavelength channel and the interval value between the uplink wavelength channels;

when the initial position is larger than the calibrated uplink wavelength channel, moving to increase the uplink wavelength according to the interval value; when the starting position is smaller than the calibrated upstream wavelength channel, the shifting is to decrease the upstream wavelength according to the interval value.

18. A method for calibrating an upstream wavelength of a Passive Optical Network (PON) system, the method comprising:

the optical line terminal OLT sends at least one first signal on a time division wavelength division multiplexing (TWDM) channel, wherein the first signal indicates the sequence of the upper wavelength channel through the carried uplink wavelength channel and/or uplink wavelength channel correlation value of the TWDM channel, and the sequence is ordered from large to small or from small to large according to the wavelength and/or uplink wavelength channel correlation value.

19. The method according to claim 18, wherein the optical line termination OLT sends upstream resource information for upstream wavelength channel calibration over TWDM channels.

20. The method of claim 18, further comprising:

the OLT receives a second signal which is sent by at least one ONU and used for calibrating an uplink wavelength channel, wherein the second signal carries an identifier or related information of the ONU sending the second signal;

the OLT sends a response of the second signal to the at least one ONU, wherein the information carried in the response comprises at least one of the following: the channel identification of the current uplink wavelength, the channel identification of the current TWDM, the wavelength value of the current uplink wavelength channel, the receiving power information of the receiver and the receiving power change information of the receiver.

21. The method of claim 20, further comprising:

and after the OLT detects a second conflicting signal in an upstream resource for upstream wavelength channel calibration, the OLT notifies the ONU of detecting a third conflicting signal.

22. The method of claim 20, further comprising:

after receiving the second signal, the OLT increases the setting frequency of the uplink resource;

and/or the OLT slows down the set frequency of the uplink resource after not receiving the second signal.

23. An optical network unit, ONU, comprising:

and the calibration device is used for calibrating the uplink wavelength channels according to the sequence of the correlation values of the uplink wavelength channels and/or the uplink wavelength channels, wherein the sequence is the sequence from large to small or from small to large according to the correlation values of the uplink wavelength channels and/or the uplink wavelength channels.

24. The ONU of claim 23, wherein the calibration means comprises:

an obtaining module, configured to obtain at least one first signal in at least one TWDM channel in a PON system, where the first signal indicates an order of uplink wavelength channels by using an uplink wavelength value of the carried TWDM channel and/or a correlation value of the uplink wavelength channel;

25. The ONU of claim 24, wherein the calibration module comprises:

a determining unit, configured to determine an initial position for calibrating the selected uplink wavelength channel;

and the calibration unit is used for calibrating the selected uplink wavelength channel from the initial position.

26. The ONU of claim 25, wherein the determining unit determines the start position for calibrating the selected upstream wavelength channel by one of:

when the calibrated uplink wavelength channel does not exist, selecting the maximum wavelength or the minimum wavelength in the tuning range supported by the self as the starting position;

27. An optical line termination, OLT, comprising:

a first sending module, configured to send at least one first signal on a time division wavelength division multiplexing TWDM channel, where the first signal indicates an order of upper wavelength channels through an upper wavelength channel and/or an upper wavelength channel correlation value of the carried TWDM channel, where the order is a sequence according to wavelengths and/or upper wavelength channel correlation values from large to small or from small to large.

28. The OLT of claim 27, wherein the first sending module is further configured to send uplink resource information for uplink wavelength channel calibration over a TWDM channel.

29. The OLT of claim 27, further comprising:

the receiving module is configured to receive a second signal for uplink wavelength channel calibration, where the second signal carries an identifier or related information of an ONU that sends the second signal, and the ONU is configured to send the second signal to the receiving module;

a second sending module, configured to send a response to the second signal to the at least one ONU, where information carried in the response includes at least one of: the channel identification of the current uplink wavelength, the channel identification of the current TWDM, the wavelength value of the current uplink wavelength channel, the receiving power information of the receiver and the receiving power change information of the receiver.

30. The OLT of claim 29, further comprising:

and the notification module is used for notifying the OLT of detecting a third conflicting signal by the ONU after detecting the second conflicting signal in an upstream resource for upstream wavelength channel calibration.

31. The OLT of claim 29, further comprising:

an increasing module, configured to increase a set frequency of an uplink resource after receiving the second signal; and/or

And the reducing module is used for slowing down the set frequency of the uplink resource after the second signal is not received.