CN112235048B - Dispersion estimation method and device based on bit error rate - Google Patents

Dispersion estimation method and device based on bit error rate Download PDF

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CN112235048B
CN112235048B CN202011077726.7A CN202011077726A CN112235048B CN 112235048 B CN112235048 B CN 112235048B CN 202011077726 A CN202011077726 A CN 202011077726A CN 112235048 B CN112235048 B CN 112235048B
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dispersion
error rate
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CN112235048A (en
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魏俊宇
左震
苏绍瑾
李申
何静
郭晓俊
孙备
蒋薇
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National University of Defense Technology
Hunan University of Technology
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Hunan University of Technology
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    • 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
    • H04B10/25—Arrangements specific to fibre transmission
    • H04B10/2507—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion
    • H04B10/2513—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion due to chromatic dispersion
    • H04B10/2525—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion due to chromatic dispersion using dispersion-compensating fibres
    • 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
    • H04B10/0795—Performance monitoring; Measurement of transmission parameters
    • H04B10/07953—Monitoring or measuring OSNR, BER or Q
    • 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
    • H04B10/60—Receivers
    • H04B10/61—Coherent receivers
    • H04B10/616—Details of the electronic signal processing in coherent optical receivers
    • H04B10/6161—Compensation of chromatic dispersion
    • 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
    • H04B10/60—Receivers
    • H04B10/66—Non-coherent receivers, e.g. using direct detection
    • H04B10/69—Electrical arrangements in the receiver
    • H04B10/695—Arrangements for optimizing the decision element in the receiver, e.g. by using automatic threshold control

Abstract

The invention discloses a dispersion estimation method based on bit error rate, which comprises the steps of starting from an initial dispersion value, sequentially calculating bit error rate values in an optical fiber link by using scanning step lengths of different dispersion values, obtaining a corresponding fitting relation between the dispersion values and the bit error rate values, and finally obtaining the optimal solution of a link dispersion estimation value by using a proposed quick search algorithm. The invention also discloses a dispersion estimation device based on the error rate, which comprises an optical fiber signal performance monitoring unit, an adjustable dispersion compensation unit and a calculation unit, and can dynamically and rapidly adjust the compensation dispersion value of the optical fiber link according to the dispersion estimation method based on the error rate, carry out signal sampling on the optical fiber link, provide strong calculation resources of the link dispersion estimation value and finally obtain the dispersion estimation accurate value of the optical fiber link.

Description

Dispersion estimation method and device based on bit error rate
Technical Field
The present invention relates to dispersion measurement in optical fiber communication transmission, and more particularly, to a method and apparatus for estimating dispersion based on bit error rate.
Background
With the further development of big data, internet of things and cloud computing technology, the data transmission requirements of people are continuously improved, the transmission distance of an optical fiber transmission system is continuously increased, and the transmission capacity is also continuously increased. In an optical fiber communication system, dispersion is an important parameter for measuring the quality of an optical fiber transmission link, and when a certain dispersion exists in the optical fiber link, the error rate of the system becomes high. With the further development of the optical fiber communication system towards high speed and large capacity, the dispersion has greater and greater influence on the transmission quality of an optical fiber link, so that the dispersion value in the optical fiber communication system can be accurately and quickly estimated, and the method has important significance for realizing accurate compensation of dispersion and reliable intelligent optical fiber communication.
The existing dispersion estimation algorithm mainly comprises a dispersion search algorithm based on a frequency domain cost function and a general dispersion estimation algorithm supporting different sampling rates and realized based on FFT. The dispersion search algorithm based on the frequency domain cost function has the defect that required hardware equipment is complex and continuously increased along with the increase of the dispersion transmission distance range; the general dispersion estimation algorithm supporting different sampling rates and realized based on FFT is realized by adopting an improved frequency domain cost function on the basis of the frequency domain dispersion estimation algorithm, and is suitable for the condition of hardware with higher sampling rate. The dispersion estimation algorithm based on the low-rate sampling technology is also like a blind dispersion estimation algorithm based on fractional order Fourier transform, but the process of solving the fractional order Fourier transform is complex, the requirement on logic calculation resources is high, and the calculation estimation time is long. However, by using the dispersion estimation algorithm of the neural network, although the trained neural network model can be directly used for dispersion estimation, the signal training data set of the optical fiber link needs to be known in advance, and the dispersion cannot be rapidly estimated flexibly and dynamically under the condition that the optical fiber link is changed.
Disclosure of Invention
Aiming at the problems of low estimation algorithm efficiency, long consumed time, low estimation precision, complex estimation device and the like commonly existing in the existing dispersion estimation technology, the invention provides a dispersion estimation method and device based on a bit error rate, and the dispersion value of a link in optical fiber transmission is quickly estimated according to the corresponding relation between dispersion and the bit error rate.
The technical scheme provided by the invention is as follows: a method for estimating dispersion based on bit error rate includes following steps:
1) obtaining last calculation parameter according to last dispersion value D in last calculation parameteri-1Last dispersion value scanning step length
Figure GDA0003458780810000011
Calculating the current dispersion value D with the last recorded value of the wind vane FlagiAccording to the value of the last recorded wind vane Flag, the last dispersion value D is obtainedi-1Plus or minus last dispersion value scanning step length
Figure GDA0003458780810000012
Is worthy of obtaining the current dispersion value Di；
2) At the current dispersion value DiCarrying out dispersion compensation on the optical fiber link to obtain the total received signal data magnitude N in the optical fiber link within the preset timeiAnd error magnitude NeiAnd based on the total received data quantity value NiAnd error magnitude NeiCalculating to obtain a current dispersion value DiCorresponding current error rate value Pei；
3) According to the current dispersion value DiCurrent error rate value PeiLast recorded dispersion reference value D in last calculation parameterbaseAnd last error rate value Pei-1Updating and recording the value of the vane Flag;
4) according to the current error rate value PeiAnd the error rate reference value Pe recorded last time in last calculation parameterbaseAnd then calculating the error rate of said difference from the last recording Reference value PebaseThe absolute value of the ratio of (a) to (b) and finally the dispersion reference value D recorded last timebaseMultiplying to obtain the scanning step length of the current dispersion value
Figure GDA0003458780810000021
5) According to the current error rate value PeiAnd the last recorded minimum error rate value Pe of the last calculation parameterminDetermines the updated minimum error rate value PeminAnd updating the minimum error rate value Pe with the corresponding probabilityminIf the minimum error rate value Pe is updatedminUpdating the minimum error rate value PeminIs the current error rate value PeiAnd recording and updating the minimum error rate value PeminCorresponding dispersion value DminIs the current dispersion value DiAnd recording, and the number of iterations CepochReturning to zero; if not, updating the minimum error rate value PeminKeeping the minimum error rate value PeminKeeping unchanged and recording, and keeping minimum error rate value PeminCorresponding dispersion value DminUnchanged and recorded, and the number of iterations CepochPlus one;
6) updating the reference value Pe of the bit error ratebaseIs the current error rate value PeiAnd recording and updating the reference value Pe of the error ratebaseCorresponding dispersion reference value DbaseIs the current dispersion value DiAnd recording;
7) judging the number of iterations CepochIf the value of (D) reaches the preset threshold value, if yes, the minimum error rate value Pe is determinedminCorresponding dispersion value DminAs the link dispersion estimate, and then ends and exits, otherwise returns to step 1).
Further, before step 1), a step of initializing calculation parameters is included, which specifically includes:
s1) setting the initial dispersion value D0At an initial dispersion value D0Carrying out dispersion compensation on the optical fiber link to calculate an initial dispersion value D0Corresponding error rate value Pe0Error rate value Pe0As a minimum error rate value PeminSum error rateReference value PebaseIs a value of the initial dispersion D0As a minimum error rate value PeminCorresponding dispersion value DminAnd a bit error rate reference value PebaseCorresponding dispersion reference value DbaseAn initial value of (1);
s2) initialization iteration count CepochIs 0, and a random number generated by taking the current test time as a seed is taken as an initial dispersion value scanning step length
Figure GDA0003458780810000022
And generating a random result with values of 0 and 1 by adopting a random algorithm, wherein if the result is 0, the value of the initialized wind vane Flag is 1, and if the result is 1, the value of the initialized wind vane Flag is-1.
Further, in step S1), if the dispersion estimation is not performed before the initialization, the initial dispersion value D is obtained00ps/nm, if the dispersion estimation is performed before the initialization, the initial dispersion value D0To a minimum error rate value PeminDispersion value D corresponding to the minimum value in the history data of (2)min。
Further, the initial dispersion value D is calculated in step S1)0Corresponding error rate value Pe 0The method specifically comprises the following steps:
s11) setting the compensation dispersion value of the optical fiber link to the initial dispersion value D0；
S12) obtaining the total received signal data quantity value N in the preset time in the optical fiber link0And error magnitude Ne0；
S13) calculating an initial dispersion value D0Corresponding error rate value Pe0The function is expressed as follows:
Pe0＝Ne0/N0
in the above formula, N0For a total received signal data magnitude, Ne, within a predetermined time0The error code value in the preset time is obtained.
Further, in step 1), calculating the current dispersion value DiThe functional expression of (a) is:
Figure GDA0003458780810000031
in the above formula, i is the number of times of calculation, Di-1In order to have the last dispersion value,
Figure GDA0003458780810000032
and the Flag is the last recorded wind vane for the last dispersion value scanning step length.
Further, in step 3), the function expression for updating the value of the vane Flag is:
Figure GDA0003458780810000033
in the above formula, i is the number of times of calculation, DiFor the current dispersion value, PeiIs the current error rate value, DbaseFor the last recorded dispersion reference value, Pei-1Is the last error rate value.
Further, in step 4), the current dispersion value scanning step length is calculated
Figure GDA0003458780810000034
The functional expression of (a) is:
Figure GDA0003458780810000035
in the above formula, i is the number of times of calculation, PeiIs the current error rate value, PebaseError rate reference value for last recording, DbaseThe dispersion reference value recorded last time.
Further, updating the minimum error rate value Pe in step 5)minIs expressed as:
Figure GDA0003458780810000036
in the above formula, PeminFor the last recorded minimum error rate value, PeiIs the current error rate value, CepochIs the value of the number of iterations.
The invention also provides a dispersion estimation device based on the error rate, which comprises a dispersion compensation unit, an optical fiber signal performance monitoring unit and a calculation unit, wherein the dispersion compensation unit is connected with the optical fiber signal performance monitoring unit through an optical fiber, the calculation unit is respectively connected with the dispersion compensation unit and the optical fiber signal performance monitoring unit through serial ports, and the dispersion estimation device comprises:
the optical fiber signal performance monitoring unit is used for delaying sampling signals and counting the total received signal data quantity value N in the preset time in the optical fiber link channeliAnd error magnitude NeiAccording to the total received signal data magnitude N within a predetermined timeiAnd error magnitude NeiCalculating to obtain the current error code rate value PeiThen sending the data to a dispersion compensation unit and a calculation unit;
the dispersion compensation unit is used for receiving a dispersion value setting command from the calculation unit and the value of the last recorded wind vane Flag, taking first preset time as preheating time, starting from an initial dispersion value according to the dispersion value setting command after the preheating time is finished, and setting the last dispersion value D in the last calculation result according to the value of the last recorded wind vane Flag i-1Plus or minus last dispersion value scanning step length
Figure GDA0003458780810000041
Obtaining the current dispersion value DiAnd according to the current dispersion value DiAfter setting the dispersion value, providing dispersion compensation for the optical fiber link channel; and is also used for obtaining the current error rate value Pe from the optical fiber signal performance monitoring unitiAnd obtaining the error rate reference value Pe of the last record in the last calculation result from the calculation unitbaseCalculating the current error rate value PeiAnd the error rate reference value Pe recorded last time in the last calculation resultbaseAnd then calculates the difference from the last recorded bit error rate reference value PebaseThe absolute value of the ratio of (a) to (b), and finally the absolute value and the last recorded dispersion reference value DbaseMultiplying to obtain the current dispersion valueScanning step length
Figure GDA0003458780810000042
The calculation unit is used for generating a dispersion value setting command and sending the dispersion value setting command and the value of the wind vane Flag recorded last time in the last calculation result to the dispersion compensation unit; for obtaining current error rate value Pe from optical fiber signal performance monitoring unitiAnd last error rate value Pei-1Obtaining a current dispersion value D from the dispersion compensation unitiAccording to the current dispersion value DiCurrent error rate value PeiAnd the dispersion reference value D recorded last time in the last calculation result baseAnd last error rate value Pei-1Updating and recording the value of the vane Flag; for determining the current error rate value PeiAnd the minimum error rate value Pe recorded in the last calculation resultminDetermines the updated minimum error rate value PeminAnd updating the minimum error rate value Pe with the corresponding probabilityminIf the minimum error rate value Pe is updatedminUpdating the minimum error rate value PeminIs the current error rate value PeiAnd recording and updating the minimum error rate value PeminCorresponding dispersion value DminIs the current dispersion value DiAnd recording, and the number of iterations CepochReturning to zero; if not, updating the minimum error rate value PeminKeeping the minimum error rate value PeminKeeping unchanged and recording, and keeping minimum error rate value PeminCorresponding dispersion value DminUnchanged and recorded, and the number of iterations CepochPlus one; and also for updating the bit error rate reference value PebaseIs the current error rate value PeiAnd recording and updating the reference value Pe of the error ratebaseCorresponding dispersion reference value DbaseIs the current dispersion value DiAnd recording; and also for determining the number of iterations CepochIf the value of (D) reaches the preset threshold value, if so, the minimum error code rate value Pe is determinedminCorresponding dispersion value DminAs an estimate of link dispersion.
The present invention also proposes a computer-readable storage medium storing a computer program programmed or configured to perform the above-mentioned bit error rate-based dispersion estimation method.
Compared with the prior art, the invention has the advantages that:
the invention utilizes the influence of dispersion on the error rate, and after the numerical fitting of the related data of the dispersion and the error rate, the invention can find that the corresponding relation has linear description, and when a proper dispersion compensation value is directly given, the characteristic that the error rate value in an optical fiber link is the lowest can be obtained, thereby completing the blind dispersion estimation function based on error rate feedback, and having the obvious advantages of simple algorithm realization and low function realization cost.
Drawings
Fig. 1 is a flowchart of a method for estimating a dispersion based on a bit error rate according to an embodiment of the present invention.
Fig. 2 is a schematic structural diagram of a dispersion estimation device based on bit error rate according to an embodiment of the present invention.
Fig. 3 is a diagram illustrating a fitting relationship between chromatic dispersion and bit error rate calculated in the apparatus according to the embodiment of the present invention.
Detailed Description
The invention is further described below with reference to the drawings and specific preferred embodiments of the description, without thereby limiting the scope of protection of the invention.
As shown in fig. 1, the present invention provides a method for estimating dispersion based on bit error rate, which estimates the dispersion value of a link in optical fiber transmission based on the linear relationship between the bit error rate and the dispersion of a link channel of an optical fiber communication system.
Firstly, initializing calculation parameters, comprising the following steps:
s1) setting the initial dispersion value D0At an initial dispersion value D0Carrying out dispersion compensation on the optical fiber link, and calculating an initial dispersion value D0Corresponding error rate value Pe0Error rate value Pe0As a minimum error rate value PeminAnd a bit error rate reference value PebaseIs a value of the initial dispersion D0As a minimum error rate value PeminCorresponding dispersion value DminAnd a bit error rate reference value PebaseCorresponding chromatic dispersionReference value DbaseAn initial value of (1);
s2) initialization iteration count CepochIs 0, and a random number generated by taking the current test time as a seed is taken as an initial dispersion value scanning step length
Figure GDA0003458780810000051
And generating a random result with values of 0 and 1 by adopting a random algorithm, wherein if the result is 0, the value of the initialized wind vane Flag is 1, and if the result is 1, the value of the initialized wind vane Flag is-1.
In step S1) of the present embodiment, if the dispersion estimation is not performed before the initialization, the initial dispersion value D is obtained00ps/nm, if the dispersion estimation is performed before the initialization, the initial dispersion value D0To a minimum error rate value PeminDispersion value D corresponding to the minimum value in the history data of (2)min。
In step S1 of the present embodiment, the initial dispersion value D is calculated0Corresponding error rate value Pe0The method specifically comprises the following steps:
S11) setting the compensation dispersion value of the optical fiber link to the initial dispersion value D0；
S12) obtaining the total received signal data quantity value N in the preset time in the optical fiber link0And error magnitude Ne0；
S13) calculating an initial dispersion value D0Corresponding error rate value Pe0The function is expressed as follows:
Pe0＝Ne0/N0 (1)
in the above formula, N0For a total received signal data magnitude, Ne, within a predetermined time0The error code value in the preset time is obtained.
Then calculating from the initial dispersion value D through multiple cycles0The method comprises the following steps of starting to sequentially calculate error code rate values by scanning step lengths with different dispersion values, and calculating to obtain a link dispersion estimated value according to the corresponding relation between the dispersion values and the error code rate values:
1) obtaining last calculation parameters according to the last time of the last calculation parametersDispersion value Di-1Last dispersion value scanning step length
Figure GDA0003458780810000061
Calculating the current dispersion value D with the last recorded value of the wind vane FlagiIn this embodiment, the current dispersion value D is calculatediThe functional expression of (a) is:
Figure GDA0003458780810000062
in the above formula, i is the number of times of calculation, Di-1In order to have the last dispersion value,
Figure GDA0003458780810000063
the last dispersion value scanning step length is adopted, and Flag is a wind vane recorded last time;
in this example, when i ≧ 1 and i ═ 1, the dispersion value D in formula (2)i-1＝D0I.e. initial dispersion value D 0，
Figure GDA0003458780810000064
I.e. initial dispersion value scan step
Figure GDA0003458780810000065
The value of the wind vane Flag at this time is the value initialized in step S2);
2) at the current dispersion value DiCarrying out dispersion compensation on the optical fiber link to obtain the total received signal data magnitude N in the optical fiber link within the preset timeiAnd error magnitude NeiAnd based on the total received signal data magnitude NiAnd error magnitude NeiCalculating to obtain a current dispersion value DiCorresponding current error rate value PeiThe method specifically comprises the following steps:
2.1) setting the compensating dispersion value of the optical fiber link to the current dispersion value Di；
2.2) calculating the total received signal data quantity value N in the preset timeiAnd error magnitude Nei；
2.3) calculating the current dispersion value DiCorresponding error rate value PeiThe function is expressed as follows:
Pei＝Nei/Ni (3)
in the above formula, i is the number of times of calculation, NiFor the total received signal data magnitude Ne within a predetermined time in the present calculationiThe error code quantity value in the preset time in the calculation is obtained;
3) according to the current dispersion value DiCurrent error rate value PeiLast recorded dispersion reference value D of last calculation parameterbaseSum and last error rate value Pei-1Updating and recording the value of the wind vane Flag, wherein the function expression is as follows:
Figure GDA0003458780810000066
in the above formula, i is the number of times of calculation, DiFor the current dispersion value, PeiIs the current error rate value, D baseFor the last recorded dispersion reference value, Pei-1The last error rate value;
when i is 1, the dispersion value D in the formula (4)i-1＝D0I.e. initial dispersion value D0，Pei-1＝Pe0I.e., the initial dispersion value D calculated in step S1)0Corresponding error rate value Pe0；
4) According to the current error rate value PeiThe error rate reference value Pe recorded last time in last calculation parameterbaseAnd the last recorded dispersion reference value DbaseCalculating the scanning step length of the current dispersion value
Figure GDA0003458780810000071
The functional expression is:
Figure GDA0003458780810000072
in the above formula, i is the number of timesNumber, PeiIs the current error rate value, PebaseError rate reference value for last recording, DbaseThe dispersion reference value recorded last time;
when i is 1, the reference value Pe of error ratebase＝Pe0Dispersion reference value Dbase＝D0I.e., the bit error rate reference value Pe set in step S1)baseAnd a dispersion reference value DbaseAn initial value of (1);
5) according to the current error rate value PeiAnd the last recorded minimum error rate value Pe of the last calculation parameterminDetermines the updated minimum error rate value PeminAnd updating the minimum error rate value Pe with the corresponding probabilityminIf the minimum error rate value Pe is updatedminUpdating the minimum error rate value PeminIs the current error rate value PeiAnd recording and updating the minimum error rate value PeminCorresponding dispersion value DminIs the current dispersion value D iAnd recording, and the number of iterations CepochReturning to zero; if not, updating the minimum error rate value PeminKeeping the minimum error rate value PeminKeeping unchanged and recording, and keeping minimum error rate value PeminCorresponding dispersion value DminUnchanged and recorded, and the number of iterations CepochIs increased by one, the minimum error rate value Pe is updatedminThe functional expression of probability of (a) is:
Figure GDA0003458780810000073
in the above formula, i is the number of times of calculation, PeiFor the current error rate value, equation (6) represents the minimum error rate value PeminUpdating error rate value Pe calculated for ith timei(i.e., updating the minimum error rate value to the current error rate value) if Pei<PeminThe minimum error rate value Pe will beminUpdating error rate value Pe calculated for ith timeiAnd recording, otherwise with probability
Figure GDA0003458780810000074
Updating the minimum error rate value PeminError rate value Pe calculated for the ith timei。
6) Updating the reference value Pe of the bit error ratebaseIs the current error rate value PeiAnd recording and updating the reference value Pe of the error ratebaseCorresponding dispersion reference value DbaseIs the current dispersion value DiAnd recording the reference value Pe of error ratebaseCalculating new error code rate value as reference error code rate reference for next time, and updating dispersion value scanning step length and dispersion reference value DbaseTaking the next new dispersion value as a reference dispersion benchmark, and updating the wind vane Flag;
7) judging the number of iterations C epochIf the value of (D) reaches the preset threshold value, if so, the minimum error code rate value Pe is determinedminCorresponding dispersion value DminTaking the dispersion as a link dispersion estimated value, and then ending and exiting; if not, returning to the step 1), selecting a threshold value related to the dispersion estimation precision (namely, the error value of the estimated dispersion value and the real dispersion value) and the dispersion estimation time, and if the threshold value is larger, the dispersion estimation time is high in cost but the precision is improved; if the threshold is small, the time required is shortened but the error between the estimated dispersion value and the true dispersion value increases. The number of iterations C can be determined based on the length of the fiber, the expected requirements for error rate, the minimum step size of the dispersion scanned, the estimated error of the dispersion, and the expected estimated timeepochAnd (4) a threshold value.
The method of the invention is realized in a dispersion estimation device based on bit error rate, the device obtains a dispersion estimation value according to the dispersion estimation method based on bit error rate, as shown in figure 2, the device is arranged in an optical fiber signal transmission environment formed by an optical fiber signal transmitting module, an optical fiber signal amplifier, an adjustable amplifier, a single mode optical fiber, an optical filter, a photoelectric converter and an analog-to-digital converter which are connected in sequence, the device comprises an optical fiber signal performance monitoring unit, a dispersion compensation unit and a calculation unit, the dispersion compensation unit is arranged between the optical filter and the photoelectric converter, the optical fiber signal performance monitoring unit is connected with the output end of the analog-to-digital converter, and the dispersion compensation unit and the optical fiber signal performance monitoring unit are connected with each other The unit is connected through optical fiber, and the calculation unit is connected with the dispersion compensation unit and the optical fiber signal performance monitoring unit through serial ports respectively. The adjustable amplifier is arranged at the output end of the optical fiber signal amplifier, the amplification factor of the optical fiber signal amplifier can be adjusted, the optical fiber signal transmitting module sends optical fiber signals with various modulation formats, the optical fiber signals are amplified by the optical fiber signal amplifier, transmitted through a single mode optical fiber, sequentially processed by the optical filter, the dispersion compensation unit, the photoelectric converter and the analog-to-digital converter, and finally the obtained digital signals are received and calculated by the optical fiber signal performance monitoring unit. In this embodiment, the optical fiber signal performance monitoring unit, the dispersion compensation unit and the calculation unit at the receiving end of the dispersion estimation device based on the bit error rate are respectively transmitted in two directions, each unit sends the processing result to the other two units for further processing, for each calculation parameter in the method of the present solution, the total received signal data quantity value and the bit error quantity value in the preset time in the optical fiber link are obtained by the optical fiber signal performance monitoring unit, the bit error quantity value is obtained by the optical fiber signal performance monitoring unit, the dispersion value and the dispersion value scanning step length are obtained by the dispersion compensation unit, the minimum bit error quantity value, the bit error quantity reference value, the dispersion value corresponding to the minimum bit error quantity value, the dispersion reference value corresponding to the bit error quantity reference value, the wind vane and the iteration number are obtained by the calculation unit, each initial calculation parameter obtained in the steps of initializing calculation parameters from step S1) to step S2) is also respectively configured in each unit according to the above corresponding relationship, wherein the initial dispersion value D 0And initial dispersion value scanning step
Figure GDA0003458780810000081
Arranged in a dispersion compensating unit, with a minimum bit error rate value PeminError rate reference value PebaseMinimum error rate value PeminCorresponding dispersion value DminError rate reference value PebaseCorresponding dispersion reference value DbaseVane Flag and iteration number CepochAre arranged in the calculation unit, and the dispersion compensation unit then calculates the initial dispersion value D0Providing dispersion compensation, initial dispersion value, for an optical fiber linkD0Corresponding total received signal data magnitude N in preset time0And error magnitude Ne0The initial dispersion value D is obtained by the optical fiber signal performance monitoring unit0Corresponding error rate value Pe0The optical fiber signal performance monitoring unit calculates the optical fiber signal performance according to the formula (1).
The operation flow of the dispersion estimation device based on the bit error rate of the embodiment is as follows:
the calculation unit generates a dispersion value setting command and sends the dispersion value setting command and the value of the wind vane Flag recorded last time in the last calculation result to the dispersion compensation unit;
the dispersion compensation unit receives a dispersion value setting command from the calculation unit and a value of a last recorded wind vane Flag, first preset time is taken as preheating time, and after the preheating time is finished, the dispersion compensation unit sets a command from an initial dispersion value D according to the dispersion value 0Initially, based on the last dispersion value D in the last calculationi-1Last dispersion value scanning step length
Figure GDA0003458780810000091
And the last recorded value of the wind vane Flag is calculated according to the formula (2) to obtain the current dispersion value DiAnd according to the current dispersion value DiAfter setting the dispersion value, providing dispersion compensation for the optical fiber link;
the optical fiber signal performance monitoring unit is used for delaying the sampling signal and counting the total received signal data quantity value N in the preset time in the optical fiber link channeliAnd error magnitude NeiAccording to the total received signal data magnitude N within a predetermined timeiAnd error magnitude NeiCalculating to obtain the current error rate value Pe according to the formula (3)iThen sending the data to a dispersion compensation unit and a calculation unit;
the calculation unit obtains the current error rate value Pe from the optical fiber signal performance monitoring unitiAnd last error rate value Pei-1Obtaining a current dispersion value D from the dispersion compensation unitiAccording to the current dispersion value DiCurrent error rate value PeiAnd the dispersion reference value D recorded last time in the last calculation resultbaseAnd last error rate value Pei-1Updating and recording the value of the wind vane Flag according to the formula (4);
the dispersion compensation unit obtains the current error rate value Pe from the optical fiber signal performance monitoring unitiAnd obtaining the error rate reference value Pe of the last record in the last calculation result from the calculation unit baseAccording to the current error rate value PeiAnd the error rate reference value Pe recorded last time in the last calculation resultbaseAnd the last recorded dispersion reference value DbaseCalculating the scanning step length of the current dispersion value according to the formula (5)
Figure GDA0003458780810000092
Then the computing unit calculates the current error rate value PeiAnd the minimum error rate value Pe recorded in the last calculation resultminDetermines an updated minimum error rate value Pe according to equation (6)minAnd updating the minimum error rate value Pe with the corresponding probabilityminIf the minimum error rate value Pe is updatedminUpdating the minimum error rate value PeminIs the current error rate value PeiAnd recording and updating the minimum error rate value PeminCorresponding dispersion value DminIs the current dispersion value DiAnd recording, and the number of iterations CepochReturning to zero; if not, updating the minimum error rate value PeminKeeping the minimum error rate value PeminKeeping unchanged and recording, and keeping minimum error rate value PeminCorresponding dispersion value DminUnchanged and recorded, and the number of iterations CepochPlus one;
the calculation unit then updates the bit error rate reference value PebaseIs the current error rate value PeiAnd recording and updating the reference value Pe of the error ratebaseCorresponding dispersion reference value DbaseIs the current dispersion value DiAnd recording;
finally, the calculation unit judges the iteration times CepochIf the value of (D) reaches the preset threshold value, if so, the minimum error code rate value Pe is determined minCorresponding dispersion value DminError rate based dispersion estimation as an estimate of link dispersionThe device stops working, if not, each unit in the dispersion estimation device based on the error rate continues the working till the iteration number CepochReaches a preset threshold value. The corresponding relationship between different dispersion values obtained from an initial dispersion value according to different scanning steps and the error rate value of an optical fiber link calculated by the dispersion estimation device based on the error rate in this embodiment is shown in fig. 3, in which the horizontal axis is the dispersion value, the unit is ps/nm, and the vertical axis is the error rate (the unit is 10:)-7) The approximate linearity of the fitted dispersion value and error rate value and the monotonous increase and decrease relation in the estimation interval can be observed. Meanwhile, as can be easily found from fig. 3, when the dispersion value is 0ps/nm, the minimum bit error rate value can be obtained, so the link dispersion estimation value of the optical fiber link of the embodiment is 0 ps/nm.
The present invention also proposes a computer-readable storage medium storing a computer program programmed or configured to perform the above-mentioned bit error rate-based dispersion estimation method.
The foregoing is considered as illustrative of the preferred embodiments of the invention and is not to be construed as limiting the invention in any way. Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical spirit of the present invention should fall within the protection scope of the technical scheme of the present invention, unless the technical spirit of the present invention departs from the content of the technical scheme of the present invention.

Claims (10)

1. A method for estimating dispersion based on bit error rate, comprising the steps of:
1) obtaining last calculation parameter according to last dispersion value D in last calculation parameteri-1Last dispersion value scanning step length
Figure FDA0003458780800000011
Calculating the current dispersion value D with the last recorded value of the wind vane FlagiAccording to the value of the last recorded wind vane Flag, the last dispersion value D is obtainedi-1Plus or minusLast dispersion value scanning step length
Figure FDA0003458780800000012
Is worthy of obtaining the current dispersion value Di；
2) At the current dispersion value DiCarrying out dispersion compensation on the optical fiber link to obtain the total received signal data magnitude N in the optical fiber link within the preset timeiAnd error magnitude NeiAnd based on the total received signal data magnitude NiAnd error magnitude NeiCalculating to obtain a current dispersion value DiCorresponding current error rate value Pei；
3) According to the current dispersion value DiCurrent error rate value PeiLast recorded dispersion reference value D in last calculation parameterbaseAnd last error rate value Pei-1Updating and recording the value of the vane Flag;
4) calculating the current error rate value PeiAnd the error rate reference value Pe recorded last time in last calculation parameterbaseAnd then calculates the difference from the last recorded bit error rate reference value Pe baseThe absolute value of the ratio of (a) to (b), and finally the absolute value and the last recorded dispersion reference value DbaseMultiplying to obtain the scanning step length of the current dispersion value
Figure FDA0003458780800000013
5) According to the current error rate value PeiAnd the last recorded minimum error rate value Pe of the last calculation parameterminDetermines the updated minimum error rate value PeminAnd updating the minimum error rate value Pe with the corresponding probabilityminIf the minimum error rate value Pe is updatedminUpdating the minimum error rate value PeminIs the current error rate value PeiAnd recording and updating the minimum error rate value PeminCorresponding dispersion value DminIs the current dispersion value DiAnd recording, and the number of iterations CepochReturning to zero; if not, updating the minimum error rate value PeminKeeping the minimum error rate value PeminKeeping unchanged and recording, and keeping minimum error rate value PeminCorresponding dispersion value DminUnchanged and recorded, and the number of iterations CepochPlus one;
6) updating the reference value Pe of the bit error ratebaseIs the current error rate value PeiAnd recording and updating the reference value Pe of the error ratebaseCorresponding dispersion reference value DbaseIs the current dispersion value DiAnd recording;
7) judging the number of iterations CepochIf the value of (D) reaches the preset threshold value, if yes, the minimum error rate value Pe is determinedminCorresponding dispersion value DminAs the link dispersion estimate, and then ends and exits, otherwise returns to step 1).
2. The method for estimating chromatic dispersion based on bit error rate according to claim 1, characterized in that step 1) includes a step of initializing calculation parameters, specifically including:
s1) setting the initial dispersion value D0At an initial dispersion value D0Carrying out dispersion compensation on the optical fiber link, and calculating an initial dispersion value D0Corresponding error rate value Pe0Error rate value Pe0As a minimum error rate value PeminAnd a bit error rate reference value PebaseIs a value of the initial dispersion D0As a minimum error rate value PeminCorresponding dispersion value DminAnd a bit error rate reference value PebaseCorresponding dispersion reference value DbaseAn initial value of (1);
s2) initialization iteration count CepochIs 0, and a random number generated by taking the current test time as a seed is taken as an initial dispersion value scanning step length
Figure FDA0003458780800000021
And generating a random result with values of 0 and 1 by adopting a random algorithm, wherein if the result is 0, the value of the initialized wind vane Flag is 1, and if the result is 1, the value of the initialized wind vane Flag is-1.
3. The fault-based method of claim 2The method for estimating the chromatic dispersion of the code rate is characterized in that in the step S1), if the chromatic dispersion estimation is not carried out before the initialization, the initial chromatic dispersion value D is00ps/nm, if the dispersion estimation is performed before the initialization, the initial dispersion value D 0Is the minimum error rate value PeminThe dispersion value D corresponding to the minimum value in the history datamin。
4. The method for estimating dispersion based on bit error rate according to claim 1, wherein the initial dispersion value D is calculated in step S1)0Corresponding error rate value Pe0The method specifically comprises the following steps:
s11) setting the compensation dispersion value of the optical fiber link to the initial dispersion value D0；
S12) obtaining the total received signal data quantity value N in the preset time in the optical fiber link0And error magnitude Ne0；
S13) calculating an initial dispersion value D0Corresponding error rate value Pe0The function is expressed as follows:
Pe0＝Ne0/N0
in the above formula, N0For a total received signal data magnitude, Ne, within a predetermined time0The error code value in the preset time is obtained.
5. The method of estimating bit error rate-based dispersion according to claim 1, wherein in step 1), the current dispersion value D is calculatediThe functional expression of (a) is:
Figure FDA0003458780800000022
in the above formula, i is the number of times of calculation, Di-1In order to have the last dispersion value,
Figure FDA0003458780800000023
and the Flag is the last recorded wind vane for the last dispersion value scanning step length.
6. The method of estimating a dispersion based on a bit error rate according to claim 1, wherein in the step 3), the function expression for updating the value of the vane Flag is:
Figure FDA0003458780800000024
in the above formula, i is the number of times of calculation, D iAs the current dispersion value, PeiIs the current error rate value, DbaseThe dispersion reference value, Pe, for the last recordingi-1Is the last error rate value.
7. The method for estimating bit error rate-based dispersion according to claim 1, wherein in step 4), the current dispersion value scan step is calculated
Figure FDA0003458780800000031
The functional expression of (a) is:
Figure FDA0003458780800000034
in the above formula, i is the number of times of calculation, PeiIs the current error rate value, PebaseError rate reference value for last recording, DbaseThe dispersion reference value recorded last time.
8. The method of estimating bit error rate-based dispersion according to claim 1, wherein the minimum bit error rate value Pe is updated in step 5)minThe functional expression of probability of (a) is:
Figure FDA0003458780800000032
in the above formula, PeminFor the last recorded minimum error rate value, PeiIs a current errorCode rate value, CepochIs the value of the number of iterations.
9. The dispersion estimation device based on the error rate is characterized by comprising an optical fiber signal performance monitoring unit, a dispersion compensation unit and a calculation unit, wherein the dispersion compensation unit is connected with the optical fiber signal performance monitoring unit through an optical fiber, the calculation unit is respectively connected with the dispersion compensation unit and the optical fiber signal performance monitoring unit through serial ports, and the calculation unit is connected with the dispersion compensation unit and the optical fiber signal performance monitoring unit through serial ports, wherein:
the optical fiber signal performance monitoring unit is used for delaying sampling signals and counting the total received signal data quantity value N in the preset time in the optical fiber link channel iAnd error magnitude NeiAccording to the total received signal data magnitude N within a predetermined timeiAnd error magnitude NeiCalculating to obtain the current error code rate value PeiThen sending the data to a dispersion compensation unit and a calculation unit;
the dispersion compensation unit is used for receiving a dispersion value setting command from the calculation unit and the value of the last recorded wind vane Flag, taking first preset time as preheating time, starting from an initial dispersion value according to the dispersion value setting command after the preheating time is finished, and setting the last dispersion value D in the last calculation result according to the value of the last recorded wind vane Flagi-1Plus or minus last dispersion value scanning step length Dstepi-1Obtaining the current dispersion value DiAnd according to the current dispersion value DiAfter setting the dispersion value, providing dispersion compensation for the optical fiber link channel; and is also used for obtaining the current error rate value Pe from the optical fiber signal performance monitoring unitiAnd obtaining the error rate reference value Pe of the last record in the last calculation result from the calculation unitbaseCalculating the current error rate value PeiAnd the error rate reference value Pe recorded last time in the last calculation resultbaseAnd then calculates the difference from the last recorded bit error rate reference value PebaseThe absolute value of the ratio of (a) to (b), and finally the absolute value and the last recorded dispersion reference value D baseMultiplying to obtain the scanning step length of the current dispersion value
Figure FDA0003458780800000033
The calculation unit is used for generating a dispersion value setting command, sending the dispersion value setting command and the value of the wind vane Flag recorded last time in the last calculation result to the dispersion compensation unit; for obtaining current error code rate value Pe from optical fiber signal performance monitoring unitiAnd last error rate value Pei-1Obtaining a current dispersion value D from the dispersion compensation unitiAccording to the current dispersion value DiCurrent error rate value PeiAnd the dispersion reference value D recorded last time in the last calculation resultbaseAnd last error rate value Pei-1Updating and recording the value of the vane Flag; for determining the current error rate value PeiAnd the minimum error rate value Pe recorded in the last calculation resultminDetermines the updated minimum error rate value PeminAnd updating the minimum error rate value Pe with the corresponding probabilityminIf the minimum error rate value Pe is updatedminUpdating the minimum error rate value PeminIs the current error rate value PeiAnd recording and updating the minimum error rate value PeminCorresponding dispersion value DminIs the current dispersion value DiAnd recording, and the number of iterations CepochReturning to zero; if not, updating the minimum error rate value PeminKeeping the minimum error rate value PeminKeeping unchanged and recording, and keeping minimum error rate value Pe minCorresponding dispersion value DminUnchanged and recorded, and the number of iterations CepochPlus one; and also for updating the bit error rate reference value PebaseIs the current error rate value PeiAnd recording and updating the reference value Pe of the error ratebaseCorresponding dispersion reference value DbaseIs the current dispersion value DiAnd recording; and also for determining the number of iterations CepochIf the value of (D) reaches the preset threshold value, if so, the minimum error code rate value Pe is determinedminCorresponding dispersion value DminAs an estimate of link dispersion.
10. A computer-readable storage medium storing a computer program programmed or configured to perform the method of estimating bit error rate-based dispersion according to any one of claims 1 to 8.
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