CN105187119B - The equidistant fault recognition method of EPON link based on optical time domain reflectometer - Google Patents
The equidistant fault recognition method of EPON link based on optical time domain reflectometer Download PDFInfo
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Abstract
The invention discloses a kind of equidistant fault recognition method of EPON link based on optical time domain reflectometer, using similarity analysis is carried out with the synthesis trace containing corresponding faulty link to actual measurement polymerization trace, the corresponding fault branch in equidistant link is judged by calculating the two Pearson correlation coefficient.This method can be in the case where not changing legacy network topological structure, the problem of effectively solving to cannot be distinguished by equidistant failure in EPON link monitoring with reference to reflection peak analytic approach.This method can penetrate peak analytic approach with reference peak and form complementation, realize that optical time domain reflectometer fast and accurately carries out non-blind area Search and Orientation in point-to-multipoint network to failure.
Description
Technical field
The invention belongs to technical field of optical fiber communication, be related to it is a kind of in EPON based on optical time domain reflectometer
The equidistant fault recognition method of EPON link.
Background technology
With the continuous upgrading of passive optical network capacity, the situation of the same communal facility of multiple users share also with day
It is all to increase.At the same time, requirement of the user to telecommunication service quality is also being improved constantly so that passive optical network optical link
Maintenance and management problem becomes increasingly conspicuous.During fixing a breakdown, how fast and accurately to position failure needs first as it
The problem of solving.In recent years, the research positioned about EPON link failure has also obtained extensive concern and research.
It is well known that in traditional point-to-point optical fiber link monitoring, optical time domain reflectometer is widely used.It
Backscattering produced by main Rayleigh scattering and Fresnel reflection when being transmitted in a fiber using optical signal and the essence being made
Close optoelectronic integration instrument, be it is a kind of can to the decay of whole optical fiber link, fusion point, connector, bending or fracture etc. ask
Inscribe the instrument measured.Its operation principle is similar to optical radar, and the luminous power returned by each point on optical fiber is composed, and obtains optical fiber
The loss information of link, and shown in the form of trajectory diagram.By optical time domain reflectometer to fibre system attenuation characteristic
Analysis can obtain length, link load and the optical fiber attenuation of optical fiber link and the distance of each failure, loss, disconnect and light
Fine strain regime etc..Because its is easy to use, practical, with the very high degree of accuracy, and with non-destructive, in optical fiber life
Widely used in production, optical cable project construction and fiber optic cable maintenance work.However, in the EPON of tree structure, light
The problem of time-domain reflectomer monitoring will run into point-to-multipoint, the back rayleigh scattering letter detected by optical time domain reflectometer
Number it is the linear superposition of each branch road back rayleigh scattering signal, so as to form multipath reflection, makes the test of optical time domain reflectometer
Curve, which can not be accurately positioned failure, to be occurred on specific branch road, so as to lose monitoring effect.But, much based on optical time domain reflection
Instrument monitoring technology is largely proposed, and has obtained a certain degree of application in passive optical network monitoring.For example, based on single
The optical time domain reflectometer monitoring technology of wavelength, tunable optical time domain reflectometer monitoring technology, Brillouin optical time-domain reflectometer monitoring
Technology and the monitoring technology of embedded optical time domain reflectometer etc..It is worth mentioning that, with reference to reflection peak analytic approach be it is a kind of more
Simple effective method, this method is based on optical time domain reflectometer, introduces a reflector to be formed with reference to anti-in each branch link
Peak is penetrated, using the optical time domain reflectometer tracing waveform under each link health status of EPON as reference value, is joined by surveying
The change of reflection peak-to-peak amplitude is examined to carry out the analysis of network state.Regrettably, this method requires each branch link length not
Can be identical, the reference reflection peak otherwise obtained with equal length link will overlap, when failure occurs equidistant just
When on link, only from will be unable to judge corresponding fault branch from each equidistant link on geometric locus.So as to also cause this
The method of kind is restricted in actual applications.
The content of the invention
Technical problem：The present invention provides one kind and can realized in passive optical network monitoring with referring to reflection peak analytic approach
Complementation, make up the reference reflection peak analytic approach based on optical time domain reflectometer and be not suitable for distinguishing asking for equidistant link failure
Topic, realizes quick, the equidistant Fault Identification side of EPON link based on optical time domain reflectometer that is accurately positioned to failure
Method.The inventive method can be eliminated timely if optical fiber is due to bending, fracture etc. caused by failure link performance deteriorate and influence just
The hidden danger of normal open letter.
Technical scheme：The equidistant fault recognition method of EPON link based on optical time domain reflectometer of the present invention, bag
Include following steps：
1) in point-to-multipoint network in each branch link reference trace acquisition, the reference trace include equidistant link
Reference trace and non-equidistant link reference trace；
2) in point-to-multipoint network in each equidistant link fault simulation trace generation；
3) generation of the fault simulation trace containing equidistant link and the synthesis trace of non-equidistant link reference trace；
4) similarity that data point in each synthesis trace polymerize data point in trace with corresponding actual measurement is analyzed, by similarity most
Link where one group of big corresponding data point as identification faulty link.
Further, the step 1) in obtain reference trace be point-to-multipoint network in each branch link be respectively at
When under normal communication state, the trace data of storage is individually gathered successively by optical time domain reflectometer, comprising on link diverse location
Various event informations.
Further：The step 2) in generate fault simulation trace as follows：
The abort situation point surveyed on trace collected first according to optical time domain reflectometer, in the step 1) obtain
Active loss W of the branch link in fault point is calculated according to following formula in reference tracer：
Wherein, WaTo show loss, namely the damage that optical time domain reflectometer can be directly read caused by branch link failure
Numerical value is consumed, N is branch link sum in network；
And then by the active loss WrThe abort situation point simulation on actual measurement trace collected with optical time domain reflectometer
Go out fault simulation trace of each equidistant link under single connection state.
Further, the step 3) in, in containing equidistant network, generate the event of each equidistant link respectively as the following formula
Barrier simulation trace AiWith each non-equidistant link reference trace B in networkjSynthesis trace Ci：
Wherein, K is link in network sum, is all equidistant number of links and non-equidistant number of links sum, i in network
For each equidistant link number, j is each non-equidistant link number.
Further, the step 4) in each synthesis trace data point polymerize the phase of data point in trace with corresponding survey
It is the Pearson correlation coefficient PCC calculated according to following formula like spending：
Wherein, xmFor the step 3) what is generated synthesizes the data point in trace, ymFor the data in actual measurement polymerization trace
Point, m is data point sequence number, and n is number of data points.
Beneficial effect：The present invention compared with prior art, with advantages below：
1st, the present invention can directly be calculated true loss by display loss, and then be quickly generated each in point-to-multipoint network
Fault simulation trace in equidistant link, generating process is simple, and directly subtracting active loss value by the value of fault point just can obtain
To fault simulation trace, efficiency can be greatly improved, guarantee is provided for the real-time of network monitor；
2nd, the present invention can solve optical time domain reflectometer passive in monitoring in the case where not changing legacy network topological structure
In optical-fiber network, when failure occurs in equidistant optical link, it is difficult to the problem of which specific branch occurs for Judging fault.In network
When non-equidistant link breaks down, the situation of reduction occurs under its corresponding reflection peak relative health；When in network
There is equidistant link, and failure is when just occurring equidistant link of one of which, can pass through the method that the present invention be provided
Differentiated and position guilty culprit link and position, be not only restricted to the length limitation of each branch circuit link in network；
3rd, similarity analysis is done to actual measurement polymerization trace and synthesis trace using Pearson correlation coefficient, can be more intuitive
Provide judged result.Polymerize the Pearson correlation coefficient of trace by calculating each synthesis trace with surveying, by correlation coefficient value compared with
Big value can show that similarity highest synthesizes trace, and then can obtain the specific link of guilty culprit, and deterministic process is very straight
See.
Brief description of the drawings
Fig. 1 is the optical time domain reflectometer monitoring of structures figure containing equidistant optical link.
Fig. 2 is experimental verification schematic diagram.
Fig. 3 is reference locus figure.
Fig. 4 is actual measurement polymerization trace and synthesis trace diagram.
Embodiment
With reference to embodiment and Figure of description, the present invention is further illustrated.
First, in EPON as shown in Figure 1, there is equidistant optical link, such as terminal optical network unit
ONU1With ONUn-1Corresponding linkage length is equal, is L1, when failure occur when among two links, at central office
Optical time domain reflectometer will be unable to judge the specific branch road that failure occurs.In order to verify the feasibility of method proposed in the present invention,
Experimental provision is built as shown in Figure 2.Set two equidistant link L intentionally in 1 × 4 network2=L4=2.22km, trunk light
Fine length L=1.01km, and analog link L respectively2With L4As the result of calculation obtained by this method when each disconnecting.
Reference trace is respectively under normal communication state by optical time domain reflection for each branch link in point-to-multipoint network
Instrument individually gathers the data of storage successively, as shown in figure 3, each linkage length L1、L2、L3And L4Respectively 1.37km, 2.22km,
During 3.01km and 2.22km, the geometric locus under the corresponding health status of each link, wherein each link fiber uses end face reflection
Mode by direct impulse signal reflex light echo time-domain reflectomer.
The generation of fault simulation trace can originally be tested by the reference trace of acquisition, choosing each equidistant link respectively
Middle respective links L is tested in confirmation2And L4, by optical time domain reflectometer collect actual measurement trace on abort situation point, referring to mark
W containing active loss is calculated on linerFault simulation trace.Specific method is：The polymerization trace surveyed in optical time domain reflectometer
On due to shown caused by branch link failure loss WaThere is following relation in the active loss of fault point with branch link：The loss provided by optical time domain reflectometer can calculate the active loss of outgoing link, Jin Ermo
Draw up failure trace of the respective links under single connection state.Simulated failure point occurs in L in this confirmatory experiment2And L4Link is about
At 2.02km, the display loss produced by fibre-optical bending is respectively 0.487dB and 0.394dB, its active loss be 3.53dB and
2.53dB.With reference to active loss, can be out of order trace, the i.e. number after reference trace trouble point by the simulation of corresponding reference trace
According to active loss value is subtracted, trace forms precipitous step-like distribution in fault point.
The generating process of the trace of link-road synthesis containing corresponding failure is, by the fault simulation trace A of above-mentioned gainediWith in network
Other link reference trace BjBy following relation generation synthesis trace Ci：
Wherein, K is link in network sum, is all equidistant number of links and non-equidistant number of links sum in network.
In this experimental verification, containing L2The synthesis trace of faulty link is by simulating L2Failure trace with health L1、L3、L4
Reference trace is formed by stacking, containing L4The synthesis trace of faulty link is by simulating L4Failure trace with health L1、L2、L3Ginseng
Trace is examined to be formed by stacking.
Trace is polymerize with actual measurement to synthesis trace and does similarity analysis, predominantly：Corresponding failure link-road synthesis trace will be contained
In data point be designated as xm, actual measurement polymerization trace data point be designated as ym, wherein n by access strong point total number, utilize Pierre
Inferior coefficient correlation (PCC) does similarity to the two as the following formula：
Do after similarity analysis, chosen most in each group PPC values to polymerizeing trace with actual measurement respectively containing corresponding synthesis trace
Faulty link in big value, corresponding synthesis trace is specific fault branch.In this confirmatory experiment, strong point correspondence of fetching
From fault point to the region of fault waveform end on geometric locus, when failure occurs in L2When in link, L is simulated2Break down
Synthesis trace PCC values be 0.9944, more than simulated failure generation L4PCC values 0.9737 in link；When failure occurs in L4
When in link, L is simulated4The PCC values of the synthesis trace broken down are 0.9969, occur L more than simulated failure2PCC in link
Value 0.9742.It follows that this method can successfully recognize that the specific fault branch in equidistant link occurs for failure.
Above-described embodiment is only the preferred embodiment of the present invention, it should be pointed out that：For the ordinary skill of the art
For personnel, under the premise without departing from the principles of the invention, some improvement and equivalent substitution can also be made, these are to the present invention
Claim be improved with the technical scheme after equivalent substitution, each fall within protection scope of the present invention.
Claims (5)
1. a kind of equidistant fault recognition method of EPON link based on optical time domain reflectometer, it is characterised in that this method
Comprise the following steps：
1) in point-to-multipoint network in each branch link reference trace acquisition, the reference trace includes the ginseng of equidistant link
Examine trace and non-equidistant link reference trace；
2) in point-to-multipoint network in each equidistant link fault simulation trace generation；
3) generation of the fault simulation trace containing equidistant link and the synthesis trace of non-equidistant link reference trace；
4) similarity that data point in each synthesis trace polymerize data point in trace with corresponding actual measurement is analyzed, by similarity maximum
Link where one group of corresponding data point as identification faulty link.
2. a kind of equidistant Fault Identification side of EPON link based on optical time domain reflectometer according to claim 1
Method, it is characterised in that the step 1) in obtain reference trace be point-to-multipoint network in each branch link be respectively at just
When under normal communications status, the trace data of storage is individually gathered successively by optical time domain reflectometer, comprising on link diverse location
Various event informations.
3. a kind of equidistant Fault Identification side of EPON link based on optical time domain reflectometer according to claim 1
Method, it is characterised in that：The step 2) in generate fault simulation trace as follows：
First according to optical time domain reflectometer collect actual measurement trace on abort situation point, in the step 1) obtain reference
Active loss W of the branch link in fault point is calculated according to following formula on tracer：
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Wherein, WaTo show loss, namely the loss number that optical time domain reflectometer can be directly read caused by branch link failure
Value, N is branch link sum in network；
And then by the active loss WrThe abort situation point on actual measurement trace collected with optical time domain reflectometer simulates each etc.
Apart from fault simulation trace of the link under single connection state, i.e. the data after reference trace trouble point subtract actual damage
Consumption value, trace forms precipitous step-like distribution in fault point.
4. the equidistant failure of a kind of EPON link based on optical time domain reflectometer according to claim 1,2 or 3 is known
Other method, it is characterised in that the step 3) in, in containing equidistant network, generate each equidistant link respectively as the following formula
Fault simulation trace AiWith each non-equidistant link reference trace B in networkjSynthesis trace Ci：
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Wherein, K is link in network sum, is all equidistant number of links and non-equidistant number of links sum in network, i is each
Equidistant link number, j is each non-equidistant link number.
5. the equidistant failure of a kind of EPON link based on optical time domain reflectometer according to claim 1,2 or 3 is known
Other method, it is characterised in that the step 4) in each synthesis trace data point polymerize data point in trace with corresponding survey
Similarity, is the Pearson correlation coefficient PCC calculated according to following formula：
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| CN106685522B (en) * | 2017-01-24 | 2019-03-12 | 东南大学 | A kind of network monitoring method and device based on poll Self Matching |
| CN110661569B (en) * | 2018-06-28 | 2022-08-02 | 中兴通讯股份有限公司 | Method, device and storage medium for optical fiber fault location |
| CN109768827B (en) * | 2018-12-26 | 2020-05-08 | 东南大学 | Link state identification method of two-dimensional optical coding and decoding system |
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