CN107171716B - Online link monitoring system and method based on related codes - Google Patents
Online link monitoring system and method based on related codes Download PDFInfo
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- CN107171716B CN107171716B CN201710385040.6A CN201710385040A CN107171716B CN 107171716 B CN107171716 B CN 107171716B CN 201710385040 A CN201710385040 A CN 201710385040A CN 107171716 B CN107171716 B CN 107171716B
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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
- H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
- H04B10/071—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using a reflected signal, e.g. using optical time domain reflectometers [OTDR]
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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
- H04B10/07—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
- H04B10/0791—Fault location on the transmission path
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
- H04L1/0056—Systems characterized by the type of code used
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Abstract
An on-line link monitoring system and method based on relevant coding relates to the field of optical fiber communication, and continuous square wave signals are generated by a square wave signal generator and are used as carriers of relevant detection code pattern sequences; modulating the continuous square wave signal according to the relevant detection code pattern sequence to generate a detection signal, combining and adding the detection signal and the data signal, and then inputting the detection signal and the data signal into a modulator; the modulator modulates continuous optical signals emitted by the signal light source according to input signals to generate pulse sequence optical signals, and the pulse sequence optical signals are input into the transmission optical fiber; receiving back scattered light from a transmission optical fiber, and converting the back scattered light into a digital signal; carrying out relevant demodulation on the digital signal and the square wave signal to extract a coded detection signal; and carrying out correlation processing on the coded detection signal and the related detection code pattern sequence, and recovering and outputting a detection signal track. The invention does not consume more time and improves the detection range and the detection resolution.
Description
Technical Field
The invention relates to the field of optical fiber communication, in particular to an online link monitoring system and method based on relevant codes.
Background
The optical time domain reflectometer is manufactured according to the principle of back scattering and reflection of light, obtains attenuation information by utilizing the back scattering light generated when the light is transmitted in an optical fiber, and can be used for measuring the attenuation of the optical fiber, the loss of a joint, the positioning of a fault point of the optical fiber, knowing the loss distribution condition of the optical fiber along the length and the like. Due to non-uniform density of the fiber material, non-uniform doping composition, and imperfections in the fiber itself, when an optical pulse is transmitted within the fiber, scattering, reflection may occur due to the nature of the fiber itself, connectors, splices, bends, or other similar events. Wherein a portion of the scattered and reflected light is returned to the optical time domain reflectometer and useful information returned is measured by the detector of the optical time domain reflectometer as time or curve segments at different positions within the optical fiber. By measuring the time taken to transmit a signal to return a signal and determining the speed of the light at the fiber, the corresponding distance can be calculated.
Passive Optical Networks (PONs), especially Ethernet Passive Optical Networks (EPONs), have become one of the best choices for various operators to solve the problem of "last mile" due to their characteristics of high bandwidth, strong anti-interference capability, high reliability, low cost, etc. According to survey data, most faults in the optical network occur on the optical link, and the faults can affect the network experience of users and even cause economic loss. With the improvement of user right awareness and the improvement of related industry standards, operators pay higher and higher cost for EPON network failures. Therefore, it is an important issue for operators to effectively perform online monitoring and fault location on the link to improve the reliability of the network and reduce the maintenance cost.
With the introduction of an optical fiber amplifier and the reduction of optical fiber loss, the transmission distance of an optical fiber is continuously increased, and a signal detected by a detector is very weak, so that the detector is required to have higher sensitivity and a larger dynamic range. In order to solve the problem of weak signals of the detector, the traditional method is to increase the resolution by repeated sampling and averaging and increase the energy of transmitted signals. The repeated sampling can increase the dynamic range of the measurement, but takes more time. Due to the limited power of the laser, increasing the energy of the incident signal only increases the pulse width of the transmitted signal, which in turn decreases the range resolution.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide an online link monitoring system and method based on related codes, which can not consume more time and can improve the detection range and the detection resolution.
In order to achieve the above object, the present invention provides an online link monitoring system based on correlation coding, comprising:
the signal light source is used for emitting continuous light signals;
a data signal generator for generating a data signal;
a detection code pattern generator for generating a sequence of related detection code patterns;
the square wave signal generator is used for generating continuous square wave signals; the continuous square wave signal generated by the square wave signal generator is used as a carrier of the relevant detection code pattern sequence, and the frequency of the continuous square wave signal is the frequency bandwidth of the downlink signal;
the multiplier is used for modulating the related detection code pattern sequence to the continuous square wave signal to generate a detection signal;
an adder for combining the data signal and the detection signal;
the modulator is used for modulating the combined data signal and the detection signal onto a continuous optical signal together to generate a pulse sequence optical signal;
the circulator is used for inputting the pulse sequence optical signal into the transmission optical fiber and inputting the back scattering signal into the reflection signal receiving unit;
the data signal receiver is used for receiving the pulse sequence optical signal of the transmission optical fiber and filtering out the data signal; the data signal receiver comprises a photodiode and a low-pass filter, wherein the photodiode is used for detecting a pulse sequence optical signal, and the low-pass filter is used for filtering out a data signal from the pulse sequence optical signal;
the reflected signal receiving unit is used for receiving the back scattering signal from the transmission optical fiber and converting the back scattering signal into a digital signal;
the relevant demodulation unit is used for carrying out relevant processing on the continuous square wave signal and the backscattering signal converted into the digital signal and extracting a coded detection signal;
and the correlation processing unit is used for performing correlation processing on the correlation detection code pattern sequence and the coded detection signal to obtain and output a detection signal curve track.
On the basis of the technical scheme, the related detection code pattern sequence generated by the detection code pattern generator is a Gray code or a CCC code.
On the basis of the technical scheme, the relevant demodulation unit demodulates the coded detection signal in a digital domain by adopting a relevant technology.
The invention also provides an online link monitoring method based on the related codes, which comprises the following steps:
s1, generating a continuous square wave signal through a square wave signal generator to serve as a carrier of a related detection code pattern sequence, wherein the frequency of the continuous square wave signal is the frequency bandwidth of a downlink signal; s2, modulating the continuous square wave signal according to the relevant detection code pattern sequence to generate a detection signal, combining and adding the detection signal and the data signal, and inputting the detection signal and the data signal into a modulator; s3, modulating a continuous optical signal emitted by a signal light source by a modulator according to an input signal to generate a pulse sequence optical signal, and inputting the pulse sequence optical signal into a transmission optical fiber; s4, receiving a pulse sequence optical signal and back scattering light from a transmission optical fiber, converting the back scattering light into a digital signal, and filtering out a data signal from the pulse sequence optical signal through a low-pass filter; s5, performing relevant demodulation on the digital signal and the square wave signal to extract a coded detection signal; and S6, carrying out correlation processing on the coded detection signal and the related detection code pattern sequence, and recovering and outputting a detection signal track.
On the basis of the technical scheme, the related detection code pattern sequence is generated by a detection code pattern generator; the backscattered light from the transmission fiber is received and converted by a reflected signal receiving unit.
On the basis of the technical scheme, the related detection code type sequence is a Gray code or a CCC code.
On the basis of the technical scheme, the data signal and the detection signal share the same signal light source, and the data signal and the detection signal occupy different frequency bands on a frequency spectrum.
On the basis of the technical scheme, the coded detection signal is demodulated in a digital domain through a relevant processing method.
The invention has the beneficial effects that:
the data signal and the detection signal share one signal light source, and because the frequency spectrum of the data signal is not overlapped with the frequency spectrum of the continuous square wave signal, the related detection code pattern sequence is modulated on the continuous square wave signal to generate the detection signal, and the frequency spectrum and the data signal are almost not overlapped, the two signals can occupy different frequency bands on the frequency spectrum through the modulation technology, so that the influence of the detection signal on the data signal is reduced, and online link monitoring and fault positioning are realized.
Because the relevant detection code pattern sequence generated by the detection code pattern generator has very good autocorrelation characteristic, no side lobe is generated after autocorrelation, the width of an autocorrelation peak is the width of a single pulse sequence, and the height is increased by L times (L is the length of the detection code pattern sequence), the measured resolution is equal to the resolution corresponding to a single pulse (for example, the pulse width of 10ns corresponds to the resolution of 1 m), the energy of the pulse is increased by L times, the time is relatively saved, and the detection range can be improved on the premise of keeping the resolution of the single pulse by adopting the relevant coding technology.
Drawings
FIG. 1 is a schematic diagram of an on-line link monitoring system based on correlation coding according to the present invention;
FIG. 2 is a schematic time domain diagram of a data signal according to the present invention;
FIG. 3 is a schematic time domain diagram of a continuous square wave signal according to the present invention;
FIG. 4 is a schematic time domain diagram of a correlation detection pattern sequence in the present invention;
FIG. 5 is a schematic diagram of the frequency domain of a data signal according to the present invention;
FIG. 6 is a schematic diagram of a detection signal in the frequency domain according to the present invention;
fig. 7 is a schematic diagram of the frequency domain of the signal input to the modulator in the present invention.
Reference numerals:
the device comprises a signal light source 1, a data signal generator 2, a detection code pattern generator 3, a square wave signal generator 4, a multiplier 5, an adder 6, a modulator 7, a circulator 8, a data signal receiver 9, a reflected signal receiving unit 10, a correlation demodulation unit 11 and a correlation processing unit 12.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples.
As shown in fig. 1, the online link monitoring system based on correlation coding of the present invention includes a signal light source 1, a data signal generator 2, a detection code pattern generator 3, a square wave signal generator 4, a multiplier 5, an adder 6, a modulator 7, a circulator 8, a data signal receiver 9, a reflected signal receiving unit 10, a correlation demodulation unit 11, and a correlation processing unit 12.
The signal light source 1 is used for emitting continuous light signals. The data signal generator 2 is arranged to generate a data signal in the time domain as shown in fig. 2 and in the frequency domain as shown in fig. 5. The probe pattern generator 3 is configured to generate a related probe pattern sequence, where the related probe pattern sequence is shown in fig. 4 in a time domain, and preferably, the generated related probe pattern sequence is a gray code or a CCC code. The square wave signal generator 4 is configured to generate a continuous square wave signal as a carrier of the associated sounding pattern sequence, where the frequency of the continuous square wave signal is the frequency bandwidth of the downlink signal, and the time domain of the continuous square wave signal is shown in fig. 3.
The multiplier 5 is configured to modulate the related detection code pattern sequence onto the continuous square wave signal to generate a detection signal, where the detection signal is in a frequency domain as shown in fig. 6. The adder 6 is used to combine the probe signal with the data signal from the data signal generator, the combined signal being spectrally as shown in figure 7 and being fed to the modulator 7. The modulator 7 is used for modulating the data signal and the detection signal onto the continuous optical signal emitted by the signal light source 1 together to generate a pulse sequence optical signal. The circulator 8 is used for inputting the pulse sequence optical signal into a transmission optical fiber and coupling the back scattering signal and the reflection signal into a reflection signal receiving unit 10. The data signal receiver 9 is used for receiving the pulse sequence optical signal in the transmission optical fiber; the data signal receiver 9 includes a Photodiode (PD) for detecting the pulse train optical signal and a Low Pass Filter (LPF) for filtering out the data signal from the pulse train optical signal. The reflected signal receiving unit 10 is used for receiving the back scattering signal from the circulator 8 and converting the back scattering signal into a digital signal. The correlation demodulation unit 11 is configured to perform correlation processing on the continuous square wave signal from the square wave signal generator 4 and the backscatter signal (converted into a digital signal) from the reflected signal receiving unit 10, and extract a coded detection signal; the correlation demodulation unit 11 demodulates the coded probe signal in the digital domain by using correlation techniques. The correlation processing unit 12 is configured to perform correlation processing on the correlation detection code pattern sequence from the detection code pattern generator 3 and the coded detection signal from the correlation demodulation unit 11, so as to obtain and output a detection signal curve trajectory.
The invention relates to an online link monitoring method based on relevant codes, which specifically comprises the following steps:
s1, generating continuous square wave signals through a square wave signal generator 4 to serve as carrier waves of subsequent related detection code pattern sequences.
S2, modulating the continuous square wave signal according to a related detection code pattern sequence to generate a detection signal; and combines and adds the probe signal and the data signal and then inputs them together to the modulator 7. Specifically, the related detection code pattern sequence is generated by a detection code pattern generator 3, and the related detection code pattern sequence is modulated onto a continuous square wave signal through a multiplier 5 to further generate a detection signal, preferably, the related detection code pattern sequence is a gray code or a CCC code; the data signal comes from a data signal generator 2.
And S3, modulating the continuous optical signal emitted by the signal light source 1 by the modulator 7 according to the input signal to generate a pulse sequence optical signal, and inputting the pulse sequence optical signal into the transmission optical fiber.
And S4, receiving the back scattering light from the transmission optical fiber through a reflection signal receiving unit, and converting the back scattering light into a digital signal.
S5, performing relevant demodulation on the digital signal and the square wave signal to extract a coded detection signal; specifically, the coded probe signal is demodulated in the digital domain by a correlation demodulation unit by using a correlation processing method.
And S6, carrying out correlation processing on the coded detection signal and the related detection code pattern sequence, recovering and outputting a detection signal track, and specifically carrying out correlation processing through a correlation processing unit.
Through the steps, the data signal and the detection signal share the same signal light source, and the data signal and the detection signal occupy different frequency bands on a frequency spectrum, so that the influence of the detection signal on the data signal is reduced, and online link monitoring and fault positioning are realized.
The present invention is not limited to the above-described embodiments, and it will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the principle of the present invention, and such modifications and improvements are also considered to be within the scope of the present invention. Those not described in detail in this specification are within the skill of the art.
Claims (8)
1. An online link monitoring system based on correlation coding, comprising:
the signal light source is used for emitting continuous light signals;
a data signal generator for generating a data signal;
a detection code pattern generator for generating a sequence of related detection code patterns;
the square wave signal generator is used for generating continuous square wave signals; the continuous square wave signal generated by the square wave signal generator is used as a carrier of the relevant detection code pattern sequence, and the frequency of the continuous square wave signal is the frequency bandwidth of the downlink signal;
the multiplier is used for modulating the related detection code pattern sequence to the continuous square wave signal to generate a detection signal;
an adder for combining the data signal and the detection signal;
the modulator is used for modulating the combined data signal and the detection signal onto a continuous optical signal together to generate a pulse sequence optical signal;
the circulator is used for inputting the pulse sequence optical signal into the transmission optical fiber and inputting the back scattering signal into the reflection signal receiving unit;
the data signal receiver is used for receiving the pulse sequence optical signal of the transmission optical fiber and filtering out the data signal; the data signal receiver comprises a photodiode and a low-pass filter, wherein the photodiode is used for detecting a pulse sequence optical signal, and the low-pass filter is used for filtering out a data signal from the pulse sequence optical signal;
the reflected signal receiving unit is used for receiving the back scattering signal from the transmission optical fiber and converting the back scattering signal into a digital signal;
the relevant demodulation unit is used for carrying out relevant processing on the continuous square wave signal and the backscattering signal converted into the digital signal and extracting a coded detection signal;
and the correlation processing unit is used for performing correlation processing on the correlation detection code pattern sequence and the coded detection signal to obtain and output a detection signal curve track.
2. The correlation-coding-based on-line link monitoring system of claim 1, wherein: and the related detection code type sequence generated by the detection code type generator is Gray code or CCC code.
3. The correlation-coding-based on-line link monitoring system of claim 1, wherein: the correlation demodulation unit demodulates the coded detection signal in a digital domain by adopting a correlation technique.
4. An online link monitoring method based on relevant coding is characterized by comprising the following steps:
s1, generating a continuous square wave signal through a square wave signal generator to serve as a carrier of a related detection code pattern sequence, wherein the frequency of the continuous square wave signal is the frequency bandwidth of a downlink signal;
s2, modulating the continuous square wave signal according to the relevant detection code pattern sequence to generate a detection signal, combining and adding the detection signal and the data signal, and inputting the detection signal and the data signal into a modulator;
s3, modulating a continuous optical signal emitted by a signal light source by a modulator according to an input signal to generate a pulse sequence optical signal, and inputting the pulse sequence optical signal into a transmission optical fiber;
s4, receiving a pulse sequence optical signal and back scattering light from a transmission optical fiber, converting the back scattering light into a digital signal, and filtering out a data signal from the pulse sequence optical signal through a low-pass filter;
s5, performing relevant demodulation on the digital signal and the square wave signal to extract a coded detection signal;
and S6, carrying out correlation processing on the coded detection signal and the related detection code pattern sequence, and recovering and outputting a detection signal track.
5. The correlation-coding-based on-line link monitoring method as claimed in claim 4, wherein: the related detection code pattern sequence is generated by a detection code pattern generator; the backscattered light from the transmission fiber is received and converted by a reflected signal receiving unit.
6. The correlation-coding-based on-line link monitoring method as claimed in claim 4, wherein: the related detection code type sequence is Gray code or CCC code.
7. The correlation-coding-based on-line link monitoring method as claimed in claim 4, wherein: the data signal and the detection signal share the same signal light source, and the data signal and the detection signal occupy different frequency bands on a frequency spectrum.
8. The correlation-coding-based on-line link monitoring method as claimed in claim 4, wherein: the coded probe signal is demodulated in the digital domain by a correlation processing method.
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| CN110278025A (en) * | 2019-07-24 | 2019-09-24 | 国家电网有限公司 | Fiber-optic monitoring method, apparatus and system |
| CN113030882B (en) * | 2020-12-30 | 2024-01-09 | 南京理工大学 | Method for constructing carrier-free ultra-wideband emission signal waveform library |
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