CN108242953B - ONU (optical network unit) ranging method, and ONU internal delay adjustment parameter determining method and device - Google Patents

ONU (optical network unit) ranging method, and ONU internal delay adjustment parameter determining method and device Download PDF

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CN108242953B
CN108242953B CN201611217712.4A CN201611217712A CN108242953B CN 108242953 B CN108242953 B CN 108242953B CN 201611217712 A CN201611217712 A CN 201611217712A CN 108242953 B CN108242953 B CN 108242953B
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onu
distance
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CN108242953A (en
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王鹏
许煜芝
邱言斌
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ZTE Corp
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
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    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
    • H04B10/077—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using a supervisory or additional signal
    • H04B10/0775—Performance monitoring and measurement of transmission parameters
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
    • H04B10/077—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using a supervisory or additional signal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
    • H04B10/079—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using measurements of the data signal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
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Abstract

The invention provides an ONU (optical network unit) ranging method, an ONU internal delay adjustment parameter determining method and an ONU internal delay adjustment parameter determining device, which are used for solving the problem of low ONU ranging precision, and comprise the following steps: adjusting the internal time delay of the ONU by using a first internal time delay adjustment parameter, wherein the first internal time delay adjustment parameter is obtained by calculation according to the actual distance between the OLT and the ONU and the measurement distance in advance; receiving a first distance between an ONU and an OLT, which is sent by the OLT; determining whether the first distance corresponds to a first internal delay adjustment parameter according to a preset corresponding relation, if so, determining that the first distance is a measurement distance between the ONU and the OLT, and if not, determining whether a difference value between the first internal delay adjustment parameter and a second internal delay adjustment parameter is greater than a preset threshold value; if the second internal time delay adjustment parameter is larger than the first internal time delay adjustment parameter, adjusting the internal time delay of the ONU according to the second internal time delay adjustment parameter, and informing the OLT of ranging again; if the distance is not larger than the preset distance, the first distance is determined to be the measured distance between the OLT and the ONU, and the accuracy of the ranging distance is ensured.

Description

ONU (optical network unit) ranging method, and ONU internal delay adjustment parameter determining method and device
Technical Field
The invention relates to the technical field of communication, in particular to an ONU (optical network unit) distance measuring method, and a method and a device for determining an ONU internal time delay adjustment parameter.
Background
With the continuous development of Optical networks, FTTH (Fiber to the Home) has been spread, and its end product ONU (Optical Network Unit) has also been widely used. In a Passive Optical Network system, different ONUs are usually located at different physical positions in an Optical Line, an OLT (Optical Line Terminal) adjusts the balanced time delay of output signals of each ONU by a ranging technique, so that uplink signals of all ONUs are as if to be located at positions of the same distance, thereby implementing time division multiplexing of the uplink signals, and another purpose of ranging is to accurately obtain an actual Optical fiber distance from the Optical Line Terminal to a certain specific ONU.
FDi＝(RTDi－RTi)×102；
FDi is an estimated value of the distance between the OLT and the ONUi, RTDi is a loop Delay (RTD) of the ONUi measured by the OLT, RTi is a minimum Response Time (RT) of the ONUi, the range is 35000 ± 1000us generally, and 102m/us is a coefficient which can best reflect the refractive index of the g.652 optical fiber and the ranging accuracy. The G987.3 standard specifies that an X Gigabit-Passive Optical Network (XGPON, 10-Gigabit-cable Passive Optical Network) system measures the fiber distance using the following formula:
FDi＝(RTTi－RspTimei－EQDi－StartTime/Rnom)×102；
FDi is an estimated value of the distance between the OLT and the ONUi, RTTi is a loop Time (RTT) after the ONUi is configured with EQDi (Equalization Delay) measured by the OLT, rstipi is a minimum response Time of the ONUi, the range is generally 35000 ± 1000us, EQDi is an Equalization Delay of the ONUi, StartTime is a standard value of an uplink burst signal starting to be sent in a ranging process, Rnom is an uplink rate, and 102m/us is a coefficient which can most reflect a g.652 optical fiber refractive index and ranging accuracy, and theoretically, the above algorithm can ensure that a ranging error is within a range of ± 1%.
In practical application, due to differences of processing time of the OLT downlink signals received and sent by the ONU in different chip schemes and differences of optical time delays of different optical modules, the accuracy of the distance measurement distance is difficult to guarantee by the algorithm, and the distance measurement error easily exceeds the range of +/-1%.
On the other hand, in order to reduce the influence on the ONU uplink service, the protocol requires that the differential distance between different ONUs under the same PON port of the OLT preferably does not exceed the limit of 20km (XGPON system 40km), but in the actual laying process of the optical line, the differential distance between different ONUs easily exceeds the limit, causing failure in discovery or ranging of part of the ONUs, and a common solution is to manually increase the quiet duration of the PON port discovery and ranging stage (for example, the quiet duration of a discovery stage is 2 frames 250us, and when the differential distance between the ONUs is large, the quiet duration can be adjusted to n × 250us, n is not less than 2), or different ONUs under different PON ports hang up different distance segments of ONUs, which may cause waste of uplink bandwidth or PON port waste, and is not favorable for full utilization of uplink bandwidth and energy saving and emission reduction.
Disclosure of Invention
The invention provides an ONU (optical network unit) ranging method, an ONU internal delay adjustment parameter determining method and an ONU internal delay adjustment parameter determining device, which are used for solving the problem of low ONU ranging precision in the prior art.
According to a first aspect of the present invention, there is provided an ONU ranging method, comprising: adjusting the internal time delay of an optical network unit ONU by using a first internal time delay adjustment parameter, wherein the first internal time delay adjustment parameter is obtained by calculation according to the actual distance and the measured distance between an optical line terminal OLT and the ONU in advance; receiving a first distance between an ONU and an OLT, which is sent by the OLT; determining whether the first distance corresponds to a first internal delay adjustment parameter according to a preset corresponding relation, if so, determining that the first distance is a measurement distance between the ONU and the OLT, and if not, determining whether a difference value between the first internal delay adjustment parameter and a second internal delay adjustment parameter is greater than a preset threshold value, wherein the second internal delay adjustment parameter corresponds to the first distance; if the second internal time delay adjustment parameter is larger than the first internal time delay adjustment parameter, adjusting the internal time delay of the ONU according to the second internal time delay adjustment parameter, and informing the OLT to re-measure the distance between the ONU and the OLT; and if not, determining that the first distance is the measured distance between the OLT and the ONU.
Optionally, the method for calculating the first internal delay adjustment parameter includes: subtracting the following formula (1) and the following formula (2) to obtain a first internal time delay adjustment parameter;
FDi＝(RTDi－RTi)×102 (1)；
wherein FDiFor measuring distance, RTD, between OLT and ONUiLoop time delay, RT, of ONU measured for OLTiMinimum response time for an ONU;
FDx＝(RTDi+△x－RTi) X 102 (2); wherein FDxΔ is the actual distance between OLT and ONUxFor the first internal delay adjustmentAnd (4) parameters.
The calculation method of the first internal delay adjustment parameter comprises the following steps: subtracting the following formula (3) and the formula (4) to obtain a first internal time delay adjustment parameter;
FDi＝(RTTi－RspTimei－EQDi－StartTime/Rnom)×102； (3)
FDx＝(RTTi－RspTimei－(EQDi－△x)－StartTime/Rnom)×102； (4)
wherein FDiFor the measured distance between OLT and ONU, RTTiONU measured for OLTiLoop time after configuration of EQDi, RspTimeiFor minimum response time of ONU, EQDiFor ONUiThe StartTime is the time for starting sending the uplink burst signal in the ranging process, RnomIs the uplink rate standard value.
Optionally, the method further includes: after the measuring distance between the OLT and the ONU is determined, the internal time delay of the ONU is adjusted according to the logic distance time delay of the ONU, and the OLT is informed to measure the distance between the ONU and the OLT again.
Optionally, the method for calculating the logical distance delay includes: calculating a logical distance delay using the following equation (3); deltaMAX＝(FDMAX-FDi)/102; wherein, ΔMAXFor logical distance delay, FDMAXFor the maximum logical ranging distance supported by the OLT, FDi is the measured distance between the OLT and the ONU.
Optionally, the method further includes: before the internal time delay of the ONU is adjusted by using a preset first internal time delay adjustment parameter, receiving an actual distance between the OLT and the ONU sent by the OLT and a third internal time delay adjustment parameter of the ONU, and establishing a corresponding relation between the actual distance and the third internal time delay adjustment parameter.
Optionally, the method further includes: and after the second internal time delay adjustment parameter is used for adjusting the internal time delay of the ONU, clearing the configured equalization time delay EQD.
According to a second aspect of the present invention, there is provided a method for determining an ONU internal delay adjustment parameter, including: acquiring the actual distance between an optical line terminal OLT and an optical network unit ONU; obtaining a measuring distance between the OLT and the ONU;
calculating to obtain an internal time delay adjustment parameter of the ONU according to the actual distance and the measured distance; and informing the actual distance and the internal time delay adjustment parameter to the ONU.
Optionally, the calculating an internal delay adjustment parameter of the ONU according to the actual distance and the measured distance includes: subtracting the following formula (1) and the formula (2) to obtain an internal time delay adjustment parameter of the ONU;
FDi＝(RTDi－RTi)×102 (1)；
wherein FDiFor measuring distances, RTDiLoop time delay, RT, of ONU measured for OLTiMinimum response time for an ONU;
FDx＝(RTDi+△x－RTi)×102 (2)；
wherein FDxΔ is the actual distancexAnd adjusting parameters for the internal time delay of the ONU.
Optionally, the calculating an internal delay adjustment parameter of the ONU according to the actual distance and the measured distance includes:
subtracting the following formula (1) and the formula (2) to obtain an internal time delay adjustment parameter of the ONU;
FDi＝(RTTi－RspTimei－EQDi－StartTime/Rnom)×102 (1)；
wherein FDiFor measuring distance, RTTiConfiguring the loop time after equalizing the time delay EQD for the ONU measured by the OLT, RspTimeiFor minimum response time of ONU, EQDiEQD configured for ONU, StartTime is the time when the uplink burst signal starts to be sent in the ranging process, RnomIs an uplink rate standard value; FDx＝(RTTi－RspTimei－(EQDi－△x)－StartTime/Rnom)×102 (2)；
Wherein FDxΔ is the actual distancexAnd adjusting parameters for the internal delay of the ONU.
Optionally, the method for informing the ONU of the actual distance and the internal delay adjustment parameter includes: a quiet Time is generated during which the ONU is informed of the actual distance and the internal delay adjustment parameter by the reserved field of the Ranging _ Time message or by a private ploam message.
According to a third aspect of the present invention, there is provided an ONU ranging apparatus comprising: the adjusting module is used for adjusting the internal time delay of the optical network unit ONU by using a first internal time delay adjusting parameter, wherein the first internal time delay adjusting parameter is obtained by calculation according to the actual distance and the measured distance between the OLT and the ONU in advance; the receiving module is used for receiving a first distance between the ONU and the OLT, which is sent by the OLT; a first determining module, configured to determine whether the first distance corresponds to the first internal delay adjustment parameter according to a preset corresponding relationship, if so, determine that the first distance is a measurement distance between the ONU and the OLT, and if not, determine whether a difference between the first internal delay adjustment parameter and the second internal delay adjustment parameter is greater than a preset threshold, where the second internal delay adjustment parameter corresponds to the first distance; a second determining module, configured to adjust the internal delay of the ONU according to the second internal delay adjustment parameter if a difference between the first internal delay adjustment parameter and the second internal delay adjustment parameter is greater than a preset threshold, and notify the OLT to re-measure the distance between the ONU and the OLT; and if the difference value between the first internal time delay adjusting parameter and the second internal time delay adjusting parameter is not larger than a preset threshold value, determining that the first distance is the measuring distance between the OLT and the ONU.
According to a fourth aspect of the present invention, an ONU internal delay adjustment parameter determining apparatus is provided, including: the acquisition module is used for acquiring the actual distance between the OLT and the ONU; the acquisition module is used for acquiring the measurement distance between the OLT and the ONU; the calculation module is used for calculating internal time delay adjustment parameters of the ONU according to the actual distance and the measured distance; and the informing module is used for informing the ONU of the actual distance and the internal time delay adjusting parameter.
The invention has the following beneficial effects:
the scheme provided by the embodiment of the invention can effectively measure the actual optical fiber distance between the OLT and a certain specific ONU, and simultaneously ensures the accuracy of the distance measurement distance, and the processing method has universality, can not distinguish the chip scheme and the type of the optical module, and can dynamically correct the distance measurement distance according to the actual situation on site; meanwhile, when the difference distance between the ONUs exceeds the limit of the protocol requirement, the quiet time of the discovery and ranging stages is shortened by adjusting the time delay inside the ONUs, and the uplink bandwidth is fully utilized.
Drawings
Fig. 1 is a flowchart of an ONU ranging method provided in a first embodiment of the present invention;
fig. 2 is a flowchart of a method for determining an ONU internal delay adjustment parameter according to a second embodiment of the present invention;
fig. 3 is a flowchart of a processing method of an ONU ranging distance adjusting stage according to a fourth embodiment of the present invention;
fig. 4 is a flowchart of a processing method for ONU ranging in practical field according to a fourth embodiment of the present invention;
fig. 5 is a block diagram of an ONU ranging apparatus provided in a fifth embodiment of the present invention;
fig. 6 is a block diagram of a device for determining an ONU internal delay adjustment parameter according to a sixth embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive efforts based on the embodiments of the present invention, shall fall within the scope of protection of the present invention.
First embodiment
The present embodiment provides an ONU ranging method, where the method is executed by an ONU, and fig. 1 is a flowchart of the method, and as shown in fig. 1, the method includes the following processing:
step 101: adjusting the internal time delay of the ONU by using a preset first internal time delay adjustment parameter;
the first internal time delay adjustment parameter is obtained by calculation according to the actual distance between the OLT and the ONU and the measured distance in advance;
in this embodiment, the ONU may store internal delay adjustment parameters corresponding to different distances in advance, and based on this, the ONU may first adjust the internal delay using a default first internal delay adjustment parameter.
For a GPON system, the method for calculating the first internal delay adjustment parameter in this embodiment includes: subtracting the following formula (1) and the following formula (2) to obtain a first internal time delay adjustment parameter;
FDi＝(RTDi－RTi)×102 (1)；
wherein FDiFor measuring distance, RTD, between OLT and ONUiLoop time delay, RT, of ONU measured for OLTiMinimum response time for an ONU;
FDx＝(RTDi+△x－RTi)×102 (2)；
wherein FDxΔ being the actual distance between OLT and said ONUxAdjusting a parameter for the first internal delay.
For the XGPON system, the method for calculating the first internal delay adjustment parameter includes:
subtracting the following formula (3) and the formula (4) to obtain a first internal time delay adjustment parameter;
FDi＝(RTTi－RspTimei－EQDi－StartTime/Rnom)×102； (3)
FDx＝(RTTi－RspTimei－(EQDi－△x)－StartTime/Rnom)×102； (4)
wherein FDiFor the measured distance between OLT and ONU, RTTiONU measured for OLTiLoop time after configuration of EQDi, RspTimeiFor minimum response time of ONU, EQDiFor ONUiThe StartTime is the time for starting sending the uplink burst signal in the ranging process, RnomIs the uplink rate standard value.
Step 102: receiving a first distance between an ONU and an OLT, which is sent by the OLT;
step 103: determining whether the first distance corresponds to a first internal delay adjustment parameter according to a preset corresponding relation, if so, determining that the first distance is a measurement distance between the ONU and the OLT, and if not, determining whether a difference value between the first internal delay adjustment parameter and a second internal delay adjustment parameter is greater than a preset threshold value, wherein the second internal delay adjustment parameter corresponds to the first distance;
in step 103, the ONU may determine whether the first distance corresponds to the first internal delay adjustment parameter according to a plurality of pre-stored distances and a plurality of internal delay adjustment parameters having a one-to-one correspondence, and if the first distance does not correspond to the first internal delay adjustment parameter, may find out a second internal delay adjustment parameter having a correspondence with the first distance according to the first distance.
Step 104: if the second internal time delay adjustment parameter is larger than the first internal time delay adjustment parameter, adjusting the internal time delay of the ONU according to the second internal time delay adjustment parameter, and informing the OLT to re-measure the distance between the ONU and the OLT; and if not, determining that the first distance is the measured distance between the OLT and the ONU.
In this step, the internal delay of the ONU is adjusted, that is, an internal delay adjustment parameter is added to or subtracted from the value of the loop delay or the equalization delay of the ONU.
Further, the method of this embodiment may further include:
before the internal time delay of the ONU is adjusted by using a preset first internal time delay adjustment parameter, receiving an actual distance between the OLT and the ONU sent by the OLT and a third internal time delay adjustment parameter of the ONU, and establishing a corresponding relation between the actual distance and the third internal time delay adjustment parameter.
Furthermore, the method provided by this embodiment may further include: and after the second internal delay adjustment parameter is used for adjusting the internal delay of the ONU, clearing the configured equalization delay EQD, which is a processing method for the XGPON system.
After determining the measurement distance between the OLT and the ONU, the method provided in this embodiment further includes a process of adjusting the internal delay of the ONU according to the logical distance delay of the ONU and notifying the OLT to re-measure the distance between the ONU and the OLT, where the method for calculating the logical distance delay includes: calculating a logical distance delay using the following equation (3); deltaMAX＝(FDMAX-FDi)/102; wherein, ΔMAXFor logical distance delay, FDMAXFor the maximum logical ranging distance supported by the OLT, FDi is the measured distance between the OLT and the ONU.
The scheme provided by the embodiment of the invention can effectively measure the actual optical fiber distance between the OLT and a certain specific ONU, and simultaneously ensures the accuracy of the distance measurement distance, and the processing method has universality, can not distinguish the chip scheme and the type of the optical module, and can dynamically correct the distance measurement distance according to the actual situation on site; meanwhile, when the difference distance between the ONUs exceeds the limit of the protocol requirement, the quiet time of the discovery and ranging stages is shortened by adjusting the time delay inside the ONUs, and the uplink bandwidth is fully utilized.
Second embodiment
The present embodiment provides a method for determining an ONU internal delay adjustment parameter, where the method is executed by an OLT, and fig. 2 is a flowchart of the method, and as shown in fig. 2, the method includes the following processing:
step 201: acquiring the actual distance between the OLT and the ONU;
step 202: obtaining a measuring distance between the OLT and the ONU;
step 203: calculating to obtain an internal time delay adjustment parameter of the ONU according to the actual distance and the measured distance;
step 204: and informing the actual distance and the internal time delay adjustment parameter to the ONU.
In this embodiment, for the GPON system, calculating an internal delay adjustment parameter of the ONU according to the actual distance and the measured distance may specifically include:
subtracting the following formula (1) and the formula (2) to obtain an internal time delay adjustment parameter of the ONU;
FDi＝(RTDi－RTi)×102 (1)；
wherein FDiFor measuring distances, RTDiLoop time delay, RT, of ONU measured for OLTiMinimum response time for an ONU;
FDx＝(RTDi+△x－RTi)×102 (2)；
wherein FDxΔ is the actual distancexAnd adjusting parameters for the internal time delay of the ONU.
In this embodiment, for the XGPON system, the calculating the internal delay adjustment parameter of the ONU according to the actual distance and the measured distance may specifically include:
subtracting the following formula (1) and the formula (2) to obtain an internal time delay adjustment parameter of the ONU;
FDi＝(RTTi－RspTimei－EQDi－StartTime/Rnom)×102 (1)；
wherein FDiFor measuring distance, RTTiConfiguring the loop time after equalizing the time delay EQD for the ONU measured by the OLT, RspTimeiFor minimum response time of ONU, EQDiEQD configured for ONU, StartTime is the time when the uplink burst signal starts to be sent in the ranging process, RnomIs an uplink rate standard value;
FDx＝(RTTi－RspTimei－(EQDi－△x)－StartTime/Rnom)×102 (2)；
wherein FDxΔ is the actual distancexAnd adjusting parameters for the internal time delay of the ONU.
Informing the ONU of the actual distance and the internal delay adjustment parameter specifically may include:
a quiet Time is generated during which the ONU is informed of the actual distance and the internal delay adjustment parameter by the reserved field of the Ranging _ Time message or by a private ploam message.
It should be noted that, the first embodiment and the second embodiment described above must be implemented on a system with an ONU internal delay adjustable, and the adjustment parameter may be saved after power down. In a passive optical network, whether a GPON system or an XGPON system, the standard requires to support ONU minimum response time, random time delay, and balanced time delay configuration, that is, under normal conditions, the ONU internal time delay may be adjusted, and the adjustment parameter may be stored in the power failure mode, mainly considering that under some special conditions, such as the ONU power failure or abnormal restart, the ONU can be recovered to a state before the power failure or before the abnormal restart after the restart, so as to ensure the accuracy during the ranging again.
Third embodiment
In a GPON system, an ONU in an O4 state sends a Serial _ Number _ ONU message to inform an OLT of Ranging after receiving a Ranging Request, and sends a Ranging _ Time message to inform the ONU of equalization delay updating and state transition after the OLT finishes Ranging. In this embodiment, the ranging distance needs to be adjusted by using the fixed-length optical fiber, and the actual optical fiber distance in the adjustment stage is known to the OLT, for example, the actual optical fiber distance between the OLT and the ONUi is 20km, and the ranging distance for the first ranging by the OLT in the GPON system is FDi, that is, FDi＝(RTDi－RTi) X 102, ONU for ensuring the ranging distance after re-ranging to be 20kmiThe parameter to be adjusted for the internal delay is Δ20kmFor GPON systems, ONU minimum response time is relatively fixed, Δ20kmMainly affecting the loop delay, i.e. FD20km＝(RTDi+△20km－RTi) X 102, subtracting the two formulas to obtain Δ20km＝(FD20km－FDi)/102。
In the XGPON system, the ONU in the O4 state sends a Registration message to inform the OLT of Ranging after receiving a Ranging Request, and sends a Ranging _ Time message to inform the ONU of equalizing delay updating and state transition after the OLT finishes Ranging. Similarly, e.g. adjustment phase OLT and ONUiThe actual fiber distance between them is 20km and is known to the OLT, the ranging distance for the first ranging of the OLT in the XGPON system is FDiI.e. FDi＝(RTTi－RspTimei－EQDiStartTime/Rnom) x 102, ONU for ensuring a ranging distance of 20km after re-rangingiThe parameter to be adjusted for the internal delay is Δ20kmFor XGPON systems, the ONU configures the EQDiLater loop time and minimum response time and StartTime/RnomRelatively fixed, Δ20kmMainly affecting the equalization delay, i.e. FD20km＝(RTTi－RspTimei－(EQDi－△20km)－StartTime/Rnom) X 102, subtracting the two formulas to obtain Δ20km＝(FD20km－FDi)/102。
△ikmΔ can be calculated by the OLT after the OLT has completed the first rangingikmCan be converted into bit unit according to the uplink rate) and generates a quiet period to inform the ONU of the actual optical fiber distance and the internal Time delay delta required to be adjusted through the reserved field of the Ranging _ Time messageikmAfter the internal delay is adjusted, the ONU may notify the OLT of re-ranging through an Acknowledge message, and for the XGPON system, the configured EQD needs to be cleared while the internal delay is adjusted.
Taking GPON system as an example, the Ranging _ Time message notification method is as shown in table 1 below.
Ranging _ Time message:
TABLE 1
Figure BDA0001192081610000111
Figure BDA0001192081610000121
Further, at the adjustment stage, if the ONU adjusts the internal delay and cannot meet the ranging accuracy, the OLT may recalculate the ΔikmAnd informing the ONU, setting the maximum repetition time, if the maximum repetition time is exceeded, the OLT can terminate the ranging process, disable the ONU and mark the ONU ranging abnormality.
Dynamically correcting the distance measurement distance according to the actual situation of the scene:
in actual field application, the optical fiber distance between the OLT and the ONU is uncertain, and in order to further improve the distance measurement precision, the distance measurement distance can be adjusted in a segmented manner in an adjustment stage, for example, delta is adopted within 0-4 km2kmAdjusting the internal time delay of the ONU, and adopting delta within 4-8 km6kmAdjusting the internal time delay of the ONU, and adopting delta within 8-12 km10kmAdjusting the internal time delay of the ONU, and adopting the method within 12-16 km
△14kmAdjusting internal time delay of ONU, and adopting delta at 16km or above20kmAnd adjusting the internal time delay of the ONU.
In practical application, the delta can be used by default after the ONU is powered on20kmAdjusting the Time delay inside the ONU, generating a quiet period after the OLT completes the first Ranging, informing the ONU of the Ranging distance through a reserved field of a Ranging _ Time message, and judging whether the current Ranging distance is equal to the delta by the ONU20kmΔ if not matching and matching current range distanceikmAnd Δ20kmToo much difference, the ONU may use ΔikmReadjusting the internal time delay and informing the OLT to perform ranging again through an ack message, if the ONU does not respond in the quiet period of the OLT, finishing the ranging by default by the OLT, and for the XGPON system, clearing the configured EQD while adjusting the internal time delay.
The quiet duration of the discovery and ranging stages is shortened through ONU internal time delay adjustment:
after the OLT finishes ranging, the internal time delay of the ONU can be further adjusted by taking the supported maximum logical ranging distance as a reference, so that all the ONUs are basically positioned at the same distance position in the discovery stage, the quiet time of the OLT in the discovery and ranging stages is shortened, the uplink bandwidth is fully utilized, and the method is similar to the ranging distance delay adjustment, for example, the logical ranging distance supported by the OLT at the maximum is 60km, and the ranging distance after the ONU is on line is FDiThen the logical distance delay that the ONU needs to adjust is Δ59km＝(FD59km－FDi) 102, in practical applications, may be Δ58km、△59kmOr delta60kmSpecifically, the logical distance adjustment delay may be determined according to an actual situation, and the logical distance adjustment delay may be calculated by the OLT after the ONU is online, and a quiet period is generated, and the ONU is notified of the logical distance adjustment value and the logical distance adjustment delay by a reserved field of a Ranging _ Time message, and after the ONU adjusts the internal delay, the ONU may notify the OLT of re-Ranging by an ack message, and the configured EQD needs to be cleared while the internal delay is adjusted.
It should be noted that the ONU ranging distance delay (i.e. the ONU internal delay adjusted for the ranging accuracy by the above algorithm) and the logical distance delay (the ONU internal delay calculated by the OLT logical distance and the ONU actual ranging distance) are in an accumulation relationship, and jointly control the delay adjustment inside the ONU, and the ONU needs to notify the OLT of the current logical distance adjustment value by a private ploam message during the re-online ranging, so that the OLT measures and calculates the actual fiber distance between the OLT and the ONU.
Through the adjustment, the OLT can increase the quiet time of the discovery and ranging stage only when a new ONU is on line, and after the logical distance delay of the new ONU is adjusted, the OLT can shorten the quiet time of the discovery and ranging stage so as to fully utilize the uplink bandwidth.
Furthermore, the algorithm and the ONU ranging processing method are not only suitable for a GPON system and an XGPN system, but also suitable for an X Gigabit-Capable Passive Optical Network (XGS-PON, 10-Gigabit-Capable Symmetric Optical Network) system and an N Gigabit-Capable Passive Optical Network (NG-PON2, 40-Gigabit-Capable Passive Optical Network) system to be proposed in the future.
Fourth embodiment
The embodiment further describes the ONU ranging scheme provided by the present invention through two examples implemented at both ends of the ONU and the OLT: as shown in fig. 3, it is a processing method of an ONU ranging distance adjusting stage in the scheme provided by the present invention, and the method includes:
s201: after the OLT ranging is completed, Δ is calculated by the algorithms described in the second and third embodimentsikm；
S202: OLT passes Ranging _ Time reserved field of message or private ploam message informs ONU of actual fiber distance and Δikm；
S203: ONU according to deltaikmAfter the internal time delay is adjusted, the OLT can be informed of ranging again through an acknowledgement message;
s204: the OLT judges whether the ranging precision after ranging again meets the requirement, if not, the step S205 is carried out, otherwise, the ranging distance adjustment is finished;
s205: the OLT judges whether the maximum repetition times of the distance measurement is exceeded, if so, the step S206 is carried out, otherwise, the step S201 is carried out to carry out distance measurement distance adjustment again;
s206: the OLT terminates the ranging, enables the ONU and marks the ONU ranging abnormity;
as shown in fig. 4, this embodiment provides a processing method for ONU ranging in field, where the method includes:
s301: ONU power-on default use delta20kmAdjusting the internal time delay;
s302: after the OLT finishes Ranging, informing the ONU of the actual optical fiber distance through a reserved field of a Ranging _ Time message or a private ploam message;
s303: the ONU judges whether the current ranging distance is equal to the delta20kmMatching, if not, entering step S304, otherwise, finishing the distance measurement correction;
s304: the ONU judges the delta matched with the current ranging distanceikmWhether or not to be equal to20kmIf the phase difference is too large, the step S305 is carried out, otherwise, the distance measurement distance correction is finished;
s305: ONU according to deltaikmAnd adjusting the internal time delay and informing the OLT of ranging again.
Fifth embodiment
The embodiment provides an ONU ranging device, which can be disposed on an ONU side, and fig. 5 is a block diagram of the ONU ranging device, and as shown in fig. 5, the ONU ranging device 50 includes the following components:
an adjusting module 51, configured to adjust an internal delay of an optical network unit ONU by using a first internal delay adjustment parameter, where the first internal delay adjustment parameter is obtained by calculating in advance according to an actual distance and a measured distance between an optical line terminal OLT and the ONU;
a receiving module 52, configured to receive a first distance between an ONU and an OLT, where the first distance is sent by the OLT;
a first determining module 53, configured to determine whether the first distance corresponds to the first internal delay adjustment parameter according to a preset corresponding relationship, if so, determine that the first distance is a measurement distance between the ONU and the OLT, and if not, determine whether a difference between the first internal delay adjustment parameter and the second internal delay adjustment parameter is greater than a preset threshold, where the second internal delay adjustment parameter corresponds to the first distance;
a second determining module 54, configured to adjust the internal delay of the ONU according to the second internal delay adjustment parameter if a difference between the first internal delay adjustment parameter and the second internal delay adjustment parameter is greater than a preset threshold, and notify the OLT to re-measure the distance between the ONU and the OLT; and if the difference value between the first internal time delay adjusting parameter and the second internal time delay adjusting parameter is not larger than a preset threshold value, determining that the first distance is the measuring distance between the OLT and the ONU.
Further, the apparatus 50 may further include: the receiving module is used for receiving the actual distance between the OLT and the ONU sent by the OLT and a third internal time delay adjusting parameter of the ONU before the internal time delay of the ONU is adjusted by using a preset first internal time delay adjusting parameter; and the establishing module is used for establishing a corresponding relation between the actual distance and the third internal time delay adjusting parameter.
Further, the above apparatus 50 further includes: and the clearing module is used for clearing the configured equalization time delay EQD after the second internal time delay adjustment parameter is used for adjusting the internal time delay of the ONU.
Sixth embodiment
The present embodiment provides an ONU internal delay adjustment parameter determining apparatus, fig. 6 is a block diagram of the apparatus, and as shown in fig. 6, the apparatus 60 includes the following components:
an obtaining module 61, configured to obtain an actual distance between the OLT and the ONU;
an obtaining module 62, configured to obtain a measurement distance between the OLT and the ONU;
the calculation module 63 is configured to calculate an internal delay adjustment parameter of the ONU according to the actual distance and the measured distance;
and an informing module 64, configured to inform the ONU of the actual distance and the internal delay adjustment parameter.
The calculating module may be specifically configured to, in a GPON system:
subtracting the following formula (1) and the formula (2) to obtain an internal time delay adjustment parameter of the ONU;
FDi＝(RTDi－RTi)×102 (1)；
wherein FDiFor measuring distances, RTDiLoop time delay, RT, of ONU measured for OLTiMinimum response time for an ONU;
FDx＝(RTDi+△x－RTi)×102 (2)；
wherein FDxΔ is the actual distancexAnd adjusting parameters for the internal time delay of the ONU.
The computing module is specifically used in the XGPON system for:
subtracting the following formula (1) and the formula (2) to obtain an internal time delay adjustment parameter of the ONU;
FDi＝(RTTi－RspTimei－EQDi－StartTime/Rnom)×102 (1)；
wherein FDiFor measuring distance, RTTiConfiguring the loop time after equalizing the time delay EQD for the ONU measured by the OLT, RspTimeiFor minimum response time of ONU, EQDieQD configured for ONU, StartTime is time for starting sending uplink burst signal in ranging process, RnomIs an uplink rate standard value;
FDx＝(RTTi－RspTimei－(EQDi－△x)－StartTime/Rnom)×102 (2)；
wherein, FDxΔ is the actual distancexAnd adjusting parameters for the internal time delay of the ONU.
The notification module 64 is specifically configured to:
a quiet Time is generated during which the ONU is informed of the actual distance and the internal delay adjustment parameter by the reserved field of the Ranging _ Time message or by a private ploam message.
Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, and the scope of the invention should not be limited to the embodiments described above.

Claims (11)

1. An ONU ranging method, comprising:
adjusting the internal time delay of an optical network unit ONU by using a first internal time delay adjustment parameter, wherein the first internal time delay adjustment parameter is obtained by calculation according to the actual distance and the measured distance between an optical line terminal OLT and the ONU in advance;
receiving a first distance between the ONU and the OLT, which is sent by the OLT;
determining whether the first distance corresponds to the first internal delay adjustment parameter according to a preset corresponding relation, if so, determining that the first distance is a measurement distance between the ONU and the OLT, and if not, determining whether a difference value between the first internal delay adjustment parameter and a second internal delay adjustment parameter is greater than a preset threshold value, wherein the second internal delay adjustment parameter corresponds to the first distance;
if the second internal time delay adjustment parameter is larger than the first internal time delay adjustment parameter, adjusting the internal time delay of the ONU according to the second internal time delay adjustment parameter, and informing the OLT to re-measure the distance between the ONU and the OLT; and if not, determining that the first distance is the measurement distance between the OLT and the ONU.
2. The method of claim 1, wherein the calculating the first internal delay adjustment parameter comprises:
subtracting the following formula (1) and formula (2) to obtain the first internal time delay adjustment parameter;
FDi＝(RTDi－RTi)×102 (1)；
wherein FDiFor the measured distance, RTD, between the OLT and the ONUiMeasuring the loop time delay, RT, of the ONU by the OLTiA minimum response time for the ONU;
FDx＝(RTDi+△x－RTi)×102 (2)；
wherein FDxΔ being the actual distance between said OLT and said ONUxAdjusting a parameter for the first internal delay.
3. The method of claim 1, wherein the calculating the first internal delay adjustment parameter comprises:
subtracting the following formula (3) and the following formula (4) to obtain the first internal time delay adjustment parameter;
FDi＝(RTTi－RspTimei－EQDi－StartTime/Rnom)×102； (3)
FDx＝(RTTi－RspTimei－(EQDi－△x)－StartTime/Rnom)×102； (4)
wherein, FDiIs a measurement distance, RTT, between the OLT and the ONUiONU measured for OLTiLoop time after configuration of EQDi, RspTimeiFor minimum response time of ONU, EQDiFor ONUiThe StartTime is the time for starting sending the uplink burst signal in the ranging process, RnomAs a standard value of the uplink rate, FDxΔ is the actual distancexAnd adjusting parameters for the internal time delay of the ONU.
4. The method of claim 1, further comprising:
after the measurement distance between the OLT and the ONU is determined, the internal time delay of the ONU is adjusted according to the logic distance time delay of the ONU, and the OLT is informed to measure the distance between the ONU and the OLT again.
5. The method of claim 4, wherein the calculating of the logical distance delay comprises:
calculating the logical distance delay using the following equation (3);
△MAX＝(FDMAX－FDi)/102；
wherein, ΔMAXFor said logical distance delay, FDMAXAnd the FDi is the measured distance between the OLT and the ONU, and is the maximum logic ranging distance supported by the OLT.
6. The method of claim 1, further comprising:
before the internal time delay of the ONU is adjusted by using a preset first internal time delay adjustment parameter, receiving an actual distance between the OLT and the ONU sent by the OLT and a third internal time delay adjustment parameter of the ONU, and establishing a corresponding relation between the actual distance and the third internal time delay adjustment parameter.
7. The method of any one of claims 1 to 6, further comprising:
and after the second internal time delay adjustment parameter is used for adjusting the internal time delay of the ONU, clearing the configured equalization time delay EQD.
8. The method according to claim 1, wherein before adjusting the internal delay of the optical network unit ONU using the first internal delay adjustment parameter, the method comprises:
acquiring the actual distance between an optical line terminal OLT and an optical network unit ONU;
obtaining a measurement distance between the OLT and the ONU;
calculating to obtain a first internal time delay adjustment parameter of the ONU according to the actual distance and the measured distance;
and informing the ONU of the actual distance and the first internal time delay adjustment parameter.
9. The method of claim 8, wherein informing the ONU of the actual distance and the first internal delay adjustment parameter comprises:
generating a quiet Time during which the actual distance and the internal delay adjustment parameter are notified to the ONU by a reserved field of a Ranging _ Time message or a private ploam message.
10. An ONU ranging apparatus, comprising:
the adjusting module is used for adjusting the internal time delay of the optical network unit ONU by using a first internal time delay adjusting parameter, wherein the first internal time delay adjusting parameter is obtained by calculation according to the actual distance between the OLT and the ONU and the measured distance in advance;
the receiving module is used for receiving a first distance between the ONU and the OLT, which is sent by the OLT;
a first determining module, configured to determine whether the first distance corresponds to the first internal delay adjustment parameter according to a preset correspondence, if so, determine that the first distance is a measured distance between the ONU and the OLT, and if not, determine whether a difference between the first internal delay adjustment parameter and a second internal delay adjustment parameter is greater than a preset threshold, where the second internal delay adjustment parameter corresponds to the first distance;
a second determining module, configured to adjust an internal delay of the ONU according to the second internal delay adjustment parameter if a difference between the first internal delay adjustment parameter and the second internal delay adjustment parameter is greater than the preset threshold, and notify the OLT to re-measure the distance between the ONU and the OLT; and if the difference value between the first internal time delay adjustment parameter and the second internal time delay adjustment parameter is not larger than the preset threshold value, determining that the first distance is the measurement distance between the OLT and the ONU.
11. The apparatus of claim 10, further comprising:
the acquisition module is used for acquiring the actual distance between the OLT and the ONU;
an obtaining module, configured to obtain a measurement distance between the OLT and the ONU;
the calculation module is used for calculating a first internal time delay adjustment parameter of the ONU according to the actual distance and the measured distance;
and the informing module is used for informing the ONU of the actual distance and the first internal time delay adjusting parameter.
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