CN117856916A - General sense integrated system - Google Patents
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Abstract
The invention discloses a general sense integrated system, belonging to the technical field of optical fiber communication and sensing; according to the invention, the multi-frequency sensing probe signals are inserted into the digital subcarrier signals at equal intervals in time, the multi-frequency sensing probe signals inserted into each frame of digital subcarrier signals are periodically changed in the frequency domain, so that an integrated communication signal is obtained, the sensing signals and the communication signals are prevented from occupying different wavelength resources respectively by modulating the integrated communication signal onto a single-frequency optical carrier, and the multi-frequency sensing probe signals do not occupy redundant frequency spectrums. The invention aims at a point-to-multipoint communication scene, and the communication receiving end comprises a plurality of communication receiving ends and is positioned at different positions; after each communication receiving end demodulates the received optical signals of the corresponding frequency band, the communication processing module simultaneously uses the multi-frequency sensing probe signals corresponding to the module as a synchronous head, so that the multiplexing of the multi-frequency sensing probe signals is realized, and the integration level of the all-in-one system is greatly improved.
Description
Technical Field
The invention belongs to the technical field of optical fiber communication and sensing, and particularly relates to a general sensing integrated system.
Background
Recently, a sense-of-general integrated system has attracted a lot of attention. Because the optical fiber network has a high-performance sensing function for monitoring the change of the external environment besides the basic data transmission function, the development of public safety and the development of intelligent cities are greatly promoted, and therefore, the research of a sense-of-general integrated system has important significance.
In order to realize economical and efficient data transmission and sensing on the same optical fiber, the system structure integrating the sense of general purpose and the sense of general purpose should have internal sense of general purpose compatibility and conciseness. The existing general sensing integrated system integrates a high-performance sensing system into a coherent optical communication network through Wavelength Division Multiplexing (WDM) and Frequency Division Multiplexing (FDM), so that simultaneous data transmission and distributed vibration sensing are realized. However, these schemes combining sensing and communication design the sensing signal and the communication signal separately, and the system structure lacks compatibility in sense of continuity, which has a problem of serious deficiency in sense of continuity integration. Moreover, as the distance of the optical fiber increases, the universal sensing integrated systems can also face the problem that the bandwidth of sensing response is reduced, and are not suitable for the problems of data transmission and link sensing of users in a point-multipoint scene.
Disclosure of Invention
Aiming at the defects or improvement demands of the prior art, the invention provides a general sense integrated system which is used for solving the technical problems that the general sense integrated system is seriously insufficient in general sense integration level, narrow in sensing response bandwidth and not applicable to data transmission and link sensing of users in a point-multipoint scene.
In order to achieve the above object, the present invention provides a sense of general integrated system comprising: the device comprises a transmitting end, a communication receiving end and a sensing receiving end; the transmitting end is respectively connected with the communication receiving end and the sensing receiving end through optical fiber links;
the transmitting end is used for inserting a multi-frequency sensing probe signal into each frame of digital subcarrier signal to obtain a communication signal; modulating a communication signal onto a single-frequency optical carrier to obtain an optical signal, amplifying the optical signal, and transmitting the optical signal to the communication receiving end through the optical fiber link; the multi-frequency sensing probe signals are sequentially inserted into each frame of digital subcarrier signals at equal intervals in the time domain, and the multi-frequency sensing probe signals are periodically changed in the frequency domain; the signals of the multi-frequency sensing probes are all arranged in the frequency domain at the frequency spectrum concave position between two subcarriers, and the frequency spectrum width of each multi-frequency sensing probe is smaller than the frequency spectrum concave position between two adjacent subcarriers; wherein the width of the spectrum concave part is B multiplied by R, B is the bandwidth of the subcarrier, and R is the roll-off coefficient of the subcarrier;
the communication receiving end comprises a plurality of communication receiving ends and is positioned at different positions; each communication receiving end is used for demodulating the received optical signals, extracting the multi-frequency sensing probe signals of the corresponding frequency band in the demodulated signals, taking the multi-frequency sensing probe signals of the corresponding frequency band as frame synchronization signals of the communication receiving ends, and carrying out frame synchronization on digital subcarrier signals sent to different communication receiving ends;
the sensing receiving end is used for receiving the back Rayleigh scattering optical signal, demodulating the back Rayleigh scattering optical signal, and extracting a multi-frequency sensing probe signal in the demodulated signal so as to sense the state of the optical fiber link; the optical signal emitted by the emitting end is transmitted back to the sensing receiving end through the optical fiber link.
Optionally, the set of multi-frequency sensing probe signals corresponds to N subcarriers, N being a positive even number.
Optionally, each communication receiving end is further configured to use the multi-frequency sensing probe signal as a frequency offset correction sequence;
center frequency of multi-frequency sensing probe signal based on transmitting endf k Center frequency in multi-frequency sensing probe signal corresponding to communication receiving endf k ’Calculating to obtain the frequency offset between the communication receiving end and the transmitting endTo compensate the frequency offset, to realize the front frequency synchronization; wherein the value of k is equal to the number of communication receiving ends and is a positive integer.
Optionally, the transmitting end includes: the device comprises an optical fiber laser, a polarization maintaining coupler, a multi-frequency local oscillator generating module, a multi-frequency local oscillator optical modulation module, a signal generating module, an optical signal modulation module and an amplifier;
the polarization maintaining coupler is used for dividing the single-frequency laser emitted by the fiber laser into two parts, wherein one part is used as local oscillation laser to be sent to the multi-frequency local oscillation optical modulation module, and the other part is used as an optical carrier to be sent to the optical signal modulation module;
the multi-frequency local oscillation generating module is used for generating multi-frequency local oscillation signals of an electric domain;
the multi-frequency local oscillation optical modulation module is used for modulating local oscillation laser according to the multi-frequency local oscillation signals of the electric domain and then sending the modulated local oscillation laser to the sensing receiving end;
the signal generation module is used for generating a digital subcarrier signal and a sensing probe signal, and inserting the sensing probe signal into a preset position of each frame of the digital subcarrier signal to obtain a communication signal; wherein the preset positionL represents frame length, the value of k is equal to the number of communication receiving ends, and m is a non-negative integer which is greater than or equal to 0 and less than or equal to k-1 in sequence;
the optical signal modulation module is used for modulating the communication signal onto an optical carrier wave to obtain an optical signal;
the amplifier is used for amplifying the optical signals, then transmitting the optical signals to different communication receiving ends through the optical fiber links in the forward direction, and transmitting the optical signals to the sensing receiving ends through the optical fiber links in the backward direction.
Optionally, the integrated ventilation system further includes an optical splitter, the communication receiving end includes a plurality of optical fiber links, and the optical fiber links are connected to the plurality of communication receiving ends through the optical splitter;
the different communication receiving ends are also used for correspondingly processing the subcarrier user data of the corresponding frequency band after the frame synchronization.
Optionally, the number k=n of the communication receiving ends all /N user Wherein N is all For transmitting the total number of terminal carriers, N user The number of sub-carriers received by a single communication receiving end is positive even number.
Optionally, each of the communication receiving ends includes: the communication local oscillator laser, the communication coherent receiver and the communication processing module;
the communication local oscillation laser is used for generating local oscillation optical signals;
the communication coherent receiver is used for receiving the forward optical signal sent by the transmitting end through the optical splitter and interfering with the local oscillation optical signal of the corresponding communication receiving end so as to coherently demodulate the optical signal to obtain demodulation signals of different users;
the communication processing module is used for extracting the multi-frequency sensing probe signals in the obtained demodulation signals, taking the sensing probe signals with corresponding frequencies as a communication synchronization head and carrying out frame synchronization on the digital subcarrier signals.
Optionally, the fiber laser is a narrow linewidth laser, the amplifier is a erbium-doped fiber amplifier, and the optical splitter is a wavelength division multiplexer or a fiber coupler.
Optionally, the sensing receiving end includes: a sensing coherent receiver and a sensing processing module;
the sensing coherent receiver is used for receiving the back Rayleigh scattering optical signal and interfering with the modulated multi-frequency local oscillation laser so as to coherently demodulate the back Rayleigh scattering optical signal to obtain a multi-frequency demodulation signal;
the sensing processing module is used for extracting multi-frequency sensing probe signals in a plurality of demodulation signals obtained by the sensing coherent receiver so as to sense the state of the optical fiber link.
In general, through the above technical solutions conceived by the present invention, the following beneficial effects can be obtained:
1. the invention provides a sense-all-in-one system, which is based on a point-to-multipoint communication scene, wherein multi-frequency sensing probe signals are respectively inserted into digital subcarrier signals at intervals in time and frequency domain to obtain integrated sense-all signals, and the sense-all-in-one system with high spectral efficiency is realized on the basis of ensuring that the potential influence of the sensing signals on the communication signals is less because the sensing signals and the communication signals occupy different wavelength resources respectively; meanwhile, the sensing probe signal is used as a synchronous head at the communication digital signal processing end, the timing synchronous error of the communication signal is estimated and compensated, and the synchronous head signal is not needed to be inserted in addition, so that the multiplexing of the sensing probe signal is realized, and the integration level of a communication system is greatly improved. Simultaneously, through a plurality of sensing probe signals staggered in time and frequency spectrum, after different sensing receiving ends and multi-frequency local oscillation light multipath interference, the sensing probe signals are respectively demodulated by using matched filtering corresponding to the multi-frequency sensing probes to obtain a plurality of sampling points which are sequentially arranged in time sequence, so that the number of the sampling points in one period of the sensing signals is increased, and the enhancement of sensing response bandwidth is realized; the method is suitable for data transmission and link perception of users in a point-multipoint scene, and achieves the aim of improving the integration level of a general sense integrated system.
2. The invention provides a general sense integrated system, wherein the signals of a multi-frequency sensing probe are all arranged at the frequency spectrum concave position between two subcarriers in the frequency domain, and the frequency spectrum width of the multi-frequency sensing probe is smaller than the frequency spectrum concave position between two adjacent subcarriers. The frequency spectrum of the multi-frequency sensing probe signal is arranged at the frequency spectrum concave positions of the two subcarriers, so that the influence of the carrier back Rayleigh scattering signal on the sensing probe at the sensing receiving terminal can be further effectively reduced.
3. The invention provides a general inductance integrated system, wherein a communication receiving end is also used for taking a sensing probe signal as a frequency offset correction sequence to perform frequency offset estimation before dispersion compensation so as to perform preposed frequency offset compensation; by further multiplexing the sensing probe signals, the problem of the front frequency synchronization of the digital subcarrier system is solved.
Drawings
Fig. 1 is a schematic structural diagram of a sense-of-general integrated system according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of a multi-frequency sensing probe signal interval inserting digital subcarrier signals according to an embodiment of the present invention.
Fig. 3 is a schematic structural diagram of another general sense integrated system according to an embodiment of the present invention.
Fig. 4 (a) is a schematic spectrum diagram of a signal of a multi-frequency sensing probe according to an embodiment of the present invention, and fig. 4 (b) is a schematic spectrum diagram of a signal of a multi-frequency sensing probe according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. In addition, the technical features of the embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.
In order to achieve the above object, as shown in fig. 1, the present invention provides a sense of general integrated system, comprising: the device comprises a transmitting end, a communication receiving end and a sensing receiving end; the transmitting end is respectively connected with the communication receiving end and the sensing receiving end through optical fiber links;
the transmitting end is used for inserting a multi-frequency sensing probe signal into each frame of digital subcarrier signal to obtain a communication signal; modulating a communication signal onto a single-frequency optical carrier to obtain an optical signal, amplifying the optical signal, and transmitting the optical signal to the communication receiving end through the optical fiber link; the multi-frequency sensing probe signals are sequentially inserted into each frame of digital subcarrier signals at equal intervals in the time domain, and the multi-frequency sensing probe signals are periodically changed in the frequency domain; the signals of the multi-frequency sensing probes are all arranged in the frequency domain at the frequency spectrum concave position between two subcarriers, and the frequency spectrum width of each multi-frequency sensing probe is smaller than the frequency spectrum concave position between two adjacent subcarriers; wherein the width of the spectrum concave part is B multiplied by R, B is the bandwidth of the subcarrier, and R is the roll-off coefficient of the subcarrier;
the communication receiving end comprises a plurality of communication receiving ends and is positioned at different positions; each communication receiving end is used for demodulating the received optical signals, extracting the multi-frequency sensing probe signals of the corresponding frequency band in the demodulated signals, taking the multi-frequency sensing probe signals of the corresponding frequency band as frame synchronization signals of the communication receiving ends, and carrying out frame synchronization on digital subcarrier signals sent to different communication receiving ends;
the sensing receiving end is used for receiving the back Rayleigh scattering optical signal, demodulating the back Rayleigh scattering optical signal, and extracting a multi-frequency sensing probe signal in the demodulated signal so as to sense the state of the optical fiber link; the optical signal emitted by the emitting end is transmitted back to the sensing receiving end through the optical fiber link.
The multi-frequency sensing probe signals inserted at equal intervals in time in each frame of digital subcarrier signal may be the same or different, and are not limited herein. As shown in fig. 2, the digital subcarrier signal is symmetrical about the optical carrier center frequency, and the subcarriers on the left and right sides are symmetrical about the optical carrier center frequency; the number of the subcarriers can be flexibly configured according to different application scenes, a group of multi-frequency sensing probe signals correspond to N subcarriers, and N is a positive even number. By way of example, there may be 6, 8, etc., without limitation. To ensure that the back-rayleigh scattered light of the sensing probe signal is correctly distinguished, the frame length of the digital sub-carrier should be equal to the total round trip time of the light in the fiber under test.
Point-to-multipoint communication is the transmission of information from a single source point to multiple destination points over a communication channel. This mode of communication allows one central node to interact with multiple branch user nodes, thereby significantly reducing deployment and maintenance costs. The plurality of branch user nodes are located in different geographical locations, so that different synchronization heads are required to perform frame synchronization respectively. In order to provide the synchronization heads of different corresponding frequency bands for different users with frame synchronization, the multi-frequency sensing probe signals periodically change in the frequency domain, and the sensing probe signals inserted in adjacent digital subcarrier signals are positioned in the frequency domainThe number of the digital subcarrier signals is different and can be set individually; inserting a sensing probe signal at a preset position of each frame of digital subcarrier signal, wherein the preset positionL represents frame length, the value of k is equal to the number of communication receiving ends, and m is a non-negative integer which is greater than or equal to 0 and less than or equal to k-1 in sequence; for example, if the communication receiving end includes 3, there are 3 positions where the multi-frequency sensing probe signal is inserted into the digital subcarrier, namely, a frame head position, a 1/3 frame length and a 2/3 frame length; specifically, 6 digital subcarrier signals are inserted into 3 sensing probe signals at equal intervals as a period, every 2 adjacent digital subcarriers in the frequency domain are assigned to a branch user node, and the multi-frequency sensing probe signals are sequentially inserted into the center frequency of 3 branch user nodes respectively, so that frame synchronization of each branch user node (communication receiving end) is realized. The sensing probe signals with different frequencies can be inserted into the frequency spectrum concave position, so that the frequency spectrum of the subcarrier signal can not be blocked.
In an alternative implementation manner, in order to reduce the influence of a digital subcarrier signal (subcarrier back-rayleigh scattering signal) in the back-rayleigh scattering optical signal on the multi-frequency sensing probe signal at the sensing receiving end, the multi-frequency sensing probe signal is placed in a frequency spectrum depression between two subcarriers in a frequency domain, and the frequency spectrum width of the multi-frequency sensing probe is smaller than the width of the frequency spectrum depression between two adjacent subcarriers; the width of the spectrum concave is B multiplied by R, B is the bandwidth of the subcarrier, and R is the roll-off coefficient of the subcarrier.
In digital subcarrier multiplexing systems, the lack of guard bands between adjacent low baud rate subcarriers exacerbates the impact of frequency offset on system performance. Therefore, frequency synchronization must be achieved by removing the frequency offset before demultiplexing with the root raised cosine filter and before dispersion compensation. In an alternative embodiment, each of the communication receiving ends is further configured to use the multi-frequency sensing probe signal as a frequency offset correction sequence; center frequency of multi-frequency sensing probe signal based on transmitting endf k Center frequency in multi-frequency sensing probe signal corresponding to communication receiving endf k ’Calculating to obtain the frequency offset between the communication receiving end and the transmitting endTo compensate the frequency offset, to realize the front frequency synchronization; wherein the value of k is equal to the number of communication receiving ends and is a positive integer.
Further, as shown in fig. 1, the transmitting end includes: the device comprises an optical fiber laser, a polarization maintaining coupler, a multi-frequency local oscillator generating module, a multi-frequency local oscillator optical modulation module, a signal generating module, an optical signal modulation module and an amplifier;
the polarization maintaining coupler is used for dividing the single-frequency laser emitted by the fiber laser into two parts, wherein one part is used as local oscillation laser to be sent to the multi-frequency local oscillation optical modulation module, and the other part is used as an optical carrier to be sent to the optical signal modulation module;
the multi-frequency local oscillation generating module is used for generating multi-frequency local oscillation signals of an electric domain;
the multi-frequency local oscillation optical modulation module is used for modulating local oscillation laser according to the multi-frequency local oscillation signals of the electric domain and then sending the modulated local oscillation laser to the optical modulator
The signal generation module is used for generating a digital subcarrier signal and a sensing probe signal, and inserting the sensing probe signal into a preset position of each frame of the digital subcarrier signal to obtain a communication signal; wherein the preset positionL represents frame length, the value of k is equal to the number of communication receiving ends, and m is a non-negative integer which is greater than or equal to 0 and less than or equal to k-1 in sequence;
the optical signal modulation module is used for modulating the communication signal onto an optical carrier wave to obtain an optical signal;
the amplifier is used for amplifying the optical signals, then transmitting the optical signals to different communication receiving ends through the optical fiber links in the forward direction, and transmitting the optical signals to the sensing receiving ends through the optical fiber links in the backward direction.
Optionally, as shown in fig. 3, the integrated ventilation system further includes an optical splitter, where the communication receiving end includes a plurality of optical fiber links, and the optical fiber links are connected to the plurality of communication receiving ends through the optical splitter;
the different communication receiving ends are also used for correspondingly processing the subcarrier user data of the corresponding frequency band after the frame synchronization.
Optionally, the number k=n of the communication receiving ends all /N user Wherein Nall is the total number of transmitting terminal carriers, N user The number of sub-carriers received by a single communication receiving end is positive even number.
The number of the communication receiving ends is determined by the total number of the subcarriers and the number of the subcarriers received by a single user, and the number of the communication receiving ends can be adjusted by adjusting the number of the subcarriers received by the single user.
As shown in fig. 3, in particular, in this embodiment, the number of communication receiving ends is three, where the communication receiving ends include a first communication receiving end, a second communication receiving end, and a third communication receiving end;
the first communication receiving end includes: the system comprises a first communication local oscillation laser, a first communication coherent receiver and a first communication processing module; the second communication receiving end comprises: the second communication local oscillation laser, the second communication coherent receiver and the second communication processing module; the third communication receiving end includes: the system comprises a third communication local oscillation laser, a third communication coherent receiver and a third communication processing module;
the first communication local oscillation laser, the second communication local oscillation laser and the third communication local oscillation laser are all used for generating local oscillation optical signals;
the first communication coherent receiver, the second communication coherent receiver and the third communication coherent receiver are all used for receiving the forward optical signal sent by the transmitting end through the optical splitter and interfering with the local oscillation signal of the corresponding communication receiving end so as to coherently demodulate the optical signal and obtain a demodulation signal;
the first communication processing module, the second communication processing module and the third communication processing module are all used for extracting multi-frequency sensing probe signals in the obtained demodulation signals, and taking the sensing probe signals with corresponding frequencies as communication synchronization heads to perform frame synchronization on digital subcarrier signals.
Wherein, the optical fiber laser in the above embodiment is a narrow linewidth laser; the amplifier may be a erbium-doped fiber amplifier, a raman amplifier, etc., preferably the amplifier is a erbium-doped fiber amplifier; the optical splitter is a wavelength division multiplexer or an optical fiber coupler; the split ratio of the polarization maintaining coupler is greater than 50:50.
It should be further noted that, as the optical signal receiver, a coherent receiver may be used, or a direct detection receiving module may be used. When the sensing receiving end adopts a sensing coherent receiver, the local oscillation optical signal of the module comes from a narrow linewidth laser.
In order to further illustrate the integrated ventilation system provided by the present invention, the following details are provided in connection with one specific embodiment:
referring to fig. 1 and 3, in this embodiment, a universal integrated transceiver system combining optical fiber communication and distributed acoustic sensing based on a shared transmitter is provided, which specifically includes: the device comprises a transmitting end, a communication receiving end and a sensing receiving end; the transmitting end is connected with the communication receiving end through an optical fiber link, and the transmitting end is connected with the sensing receiving end through a multi-frequency local oscillator optical modulation module.
At the transmitting end, the fiber laser adopts a narrow linewidth laser, and in the embodiment, single-frequency laser emitted by the fiber laser is divided into two parts by a 70:30 polarization maintaining coupler. The 70 part is used as local oscillation laser of the sensing receiver and is sent to the sensing receiving end through the multi-frequency local oscillation generating unit, the local oscillation laser generated by the multi-frequency local oscillation optical modulation module is multi-frequency laser, the multi-frequency local oscillation optical modulation module is connected with the multi-frequency local oscillation generating module, the multi-frequency local oscillation generating module generates multi-frequency electric signals, the frequency interval of the multi-frequency local oscillation generating module is equal to the frequency interval B multiplied by 2 multiplied by (1+R) among sub-carriers, and the multi-frequency local oscillation electric signals are transmitted to the multi-frequency local oscillation optical modulation module to modulate the local oscillation laser; the other part is used as an optical carrier wave to be sent to an optical signal modulation module, and then external modulation is adopted to generate a transmitting end sense-of-general integrated signal. The signal generating unit simultaneously generates communication and sensing electric signals, namely a digital subcarrier signal and a multi-frequency sensing probe signal, and inserts the multi-frequency sensing probe signal into each frame of the digital subcarrier signal to obtain a communication signal; the signals of the multi-frequency sensing probes are all arranged in the frequency domain at the frequency spectrum concave position between two subcarriers, and the frequency spectrum width of each multi-frequency sensing probe is smaller than the frequency spectrum concave position between two adjacent subcarriers; the multi-frequency sensing probe signals which are periodically changed in the frequency domain are sequentially inserted into each frame of digital subcarrier signals at equal intervals in the time domain; and sending the communication signal to an optical signal modulation module. The optical signal modulation module then modulates the communication signal onto an optical carrier wave emitted by the fiber laser. The modulated optical signal is amplified by an erbium-doped fiber amplifier and then coupled into a standard single-mode fiber for transmission. The optical signals transmitted by the optical fibers enter the communication receiving end and are received by communication coherent receivers of different communication receiving ends. The first communication coherent receiver, the second communication coherent receiver and the third communication coherent receiver respectively interfere local oscillation optical signals generated by corresponding local oscillation lasers with the received forward communication carrier wave, so that communication electric signals are obtained; the obtained communication electric signal may be 2 or 4, and in this embodiment, the example of obtaining 4 communication electric signals is XI, XQ, YI, YQ. The first communication processing module, the second communication processing module and the third communication processing module of the three different communication receiving ends respectively process the four paths of electric signals to obtain final communication information. Meanwhile, the backward Rayleigh scattering optical signal enters a sensing coherent receiver of a sensing receiving end through the circulator, the backward Rayleigh scattering optical signal received by the sensing coherent receiver is a backward Rayleigh scattering sensing carrier wave, and the sensing coherent receiver interferes a local oscillator laser of the sensing receiver with the received backward Rayleigh scattering sensing carrier wave, so that 4 paths of sensing electric signals are obtained, and XI, XQ, YI, YQ. And the sensing processing module of the sensing receiving end performs digital signal processing on the four paths of electric signals to obtain final sensing information.
Specifically, as shown in fig. 3, at the transmitting end, the signal generating module inserts the sensing probe into the digital subcarrier communication signal in the time domain and then resamples the signal to obtain the communication signal.
At the sensing receiving end, the multi-frequency back Rayleigh scattering sensing carrier wave and the multi-frequency local oscillator laser beat frequency are detected by a sensing coherent receiver, and the detected electric signals are sampled by a four-channel digital oscilloscope to obtain 4 paths of sensing electric signals, XI, XQ, YI, YQ.
At a communication receiving end, a first communication processing module sequentially resamples 4 paths of communication electric signals obtained after detection by a first communication coherent receiver and sampling by a digital oscilloscope, and obtains information sent by a transmitting end after frame timing synchronization based on a sensing probe signal, frequency synchronization based on the sensing probe signal, subcarrier demultiplexing and residual damage compensation operation.
And performing frame timing synchronization based on the correlation processing of the sensing probe, and then performing frequency synchronization by using the method as a frequency offset correction sequence to compensate the time offset and frequency offset damage of the response.
Specifically, in this embodiment, as shown in fig. 2, by inserting the multi-frequency sensing probe signal into the digital subcarrier signal at intervals in the time domain and in the frequency domain, respectively, a high-spectrum-efficiency integrated system for ventilation is realized. Meanwhile, when frame synchronization is carried out, the sensing probe signals with corresponding frequencies are used as communication synchronization heads, and the frame synchronization is carried out on the digital subcarrier signals; the sensing probe signal is used as a synchronous head at the same time at the communication digital signal processing end, the timing synchronous error of the communication signal is estimated and compensated, and the synchronous head signal is not needed to be inserted in addition, so that the multiplexing of the multi-frequency sensing probe signal is realized, and the integration level of a communication and transmission integrated system is greatly improved. By constructing a plurality of sensing probe signals staggered in time and frequency spectrum, a plurality of sampling points which are sequentially arranged in time sequence are obtained after multipath interference of a plurality of different sensing receiving ends, so that the number of the sampling points in one period of the sensing signals is increased, and sensing detection and vibration event extraction with enhanced frequency response bandwidth are realized.
Further, the signals of the multi-frequency sensing probes are all arranged in the frequency domain at the frequency spectrum concave position between two subcarriers, and the frequency spectrum width of each multi-frequency sensing probe is smaller than the frequency spectrum concave position between two adjacent subcarriers. The frequency spectrum of the sensing probe signal is arranged at the frequency spectrum concave positions of the two subcarriers, so that the influence of multiple frequencies of the carrier wave on the sensing probe at the sensing receiving terminal is effectively reduced.
In addition, in the frequency offset estimation, each communication receiving end is further configured to use the multi-frequency sensing probe signal as a pre-frequency offset correction sequence, as shown in fig. 4, and in the case of three communication receiving ends, calculate the frequency offset Δ between each communication receiving end and the transmitting endf， To realize frequency offset compensation, thereby realizing preposed frequency synchronization; the value of k is equal to the number of the communication receiving ends, is a positive integer, and takes a corresponding value according to the different numbers of the communication receiving ends. The sensing probe signal is further multiplexed in the frequency offset compensation, so that the integration level of the passsense system is further improved.
In summary, the invention provides a communication and sense integrated system, which not only can realize basic synchronization functions (including time synchronization and frequency synchronization) in a communication scene, but also can be used in a communication and sense integrated application scene, aiming at a point-to-multipoint scene, the system can be multiplexed into a multi-frequency synchronization head signal aiming at a multipoint user by utilizing a multi-frequency sensing probe, not only can perform time offset and frequency offset estimation and compensation in a communication multi-user receiving end, but also can realize sensing detection with enhanced response bandwidth by utilizing a sensing probe with periodically changed frequency domain at a back sensing receiving end. The system solves the problems that the existing general sensing integrated system separately designs the sensing signal and the communication signal, has serious insufficient integration level and narrow sensing response bandwidth, and is not suitable for data transmission and sensing of multi-point users. The integration level of the general sense integrated system is improved, and the data synchronization of the receiving ends of the multi-point users is realized.
It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the invention and is not intended to limit the invention, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (9)
1. A sense of general integration system, comprising: the device comprises a transmitting end, a communication receiving end and a sensing receiving end; the transmitting end is respectively connected with the communication receiving end and the sensing receiving end through optical fiber links;
the transmitting end is used for inserting a multi-frequency sensing probe signal into each frame of digital subcarrier signal to obtain a communication signal; modulating a communication signal onto a single-frequency optical carrier to obtain an optical signal, amplifying the optical signal, and transmitting the optical signal to the communication receiving end through the optical fiber link; the multi-frequency sensing probe signals are sequentially inserted into each frame of digital subcarrier signals at equal intervals in the time domain, and the multi-frequency sensing probe signals are periodically changed in the frequency domain; the signals of the multi-frequency sensing probes are all arranged in the frequency domain at the frequency spectrum concave position between two subcarriers, and the frequency spectrum width of each multi-frequency sensing probe is smaller than the frequency spectrum concave position between two adjacent subcarriers; wherein the width of the spectrum concave part is B multiplied by R, B is the bandwidth of the subcarrier, and R is the roll-off coefficient of the subcarrier;
the communication receiving end comprises a plurality of communication receiving ends and is positioned at different positions; each communication receiving end is used for demodulating the received optical signals, extracting the multi-frequency sensing probe signals of the corresponding frequency band in the demodulated signals, taking the multi-frequency sensing probe signals of the corresponding frequency band as frame synchronization signals of the communication receiving ends, and carrying out frame synchronization on digital subcarrier signals sent to different communication receiving ends;
the sensing receiving end is used for receiving the back Rayleigh scattering optical signal, demodulating the back Rayleigh scattering optical signal, and extracting a multi-frequency sensing probe signal in the demodulated signal so as to sense the state of the optical fiber link; the optical signal emitted by the emitting end is transmitted back to the sensing receiving end through the optical fiber link.
2. The integrated ventilation system of claim 1, wherein the set of multi-frequency sensing probe signals corresponds to N subcarriers, N being a positive even number.
3. The integrated ventilation system of claim 1, wherein each of the communication receiving terminals is further configured to use the multi-frequency sensing probe signal as a frequency offset correction sequence;
center frequency of multi-frequency sensing probe signal based on transmitting endf k Center frequency of multi-frequency sensing probe signal corresponding to communication receiving endf k ’Calculating to obtain the frequency offset delta between the communication receiving end and the transmitting endf=(f k –f k ’)To compensate the frequency offset, to realize the front frequency synchronization; wherein the value of k is equal to the number of communication receiving ends and is a positive integer.
4. A ventilation and inductance integrated system according to any one of claims 1-3, wherein the transmitting end includes: the device comprises an optical fiber laser, a polarization maintaining coupler, a multi-frequency local oscillator generating module, a multi-frequency local oscillator optical modulation module, a signal generating module, an optical signal modulation module and an amplifier;
the polarization maintaining coupler is used for dividing the single-frequency laser emitted by the fiber laser into two parts, wherein one part is used as local oscillation laser to be sent to the multi-frequency local oscillation optical modulation module, and the other part is used as an optical carrier to be sent to the optical signal modulation module;
the multi-frequency local oscillation generating module is used for generating multi-frequency local oscillation signals of an electric domain;
the multi-frequency local oscillation optical modulation module is used for modulating local oscillation laser according to the multi-frequency local oscillation signals of the electric domain and then sending the modulated local oscillation laser to the sensing receiving end;
the signal generation module is used for generating a digital subcarrier signal and a sensing probe signal, and inserting the sensing probe signal into a preset position of each frame of the digital subcarrier signal to obtain a communication signal; wherein the preset position p=L represents frame length, the value of k is equal to the number of communication receiving ends, and m is a non-negative integer which is greater than or equal to 0 and less than or equal to k-1 in sequence;
the optical signal modulation module is used for modulating the communication signal onto an optical carrier wave to obtain an optical signal;
the amplifier is used for amplifying the optical signals, then transmitting the optical signals to different communication receiving ends through the optical fiber links in the forward direction, and transmitting the optical signals to the sensing receiving ends through the optical fiber links in the backward direction.
5. The integrated system of claim 4, further comprising an optical splitter through which the fiber links are connected to a plurality of the communication receivers;
the different communication receiving ends are also used for correspondingly processing the subcarrier user data of the corresponding frequency band after the frame synchronization.
6. The integrated communication system according to claim 5, wherein the number of communication receivers k=n all /N user Wherein N is all For transmitting the total number of terminal carriers, N user The number of sub-carriers received by a single communication receiving end is positive even number.
7. The integrated ventilation system of claim 6, wherein each of the communication receiving terminals comprises: the communication local oscillator laser, the communication coherent receiver and the communication processing module;
the communication local oscillation laser is used for generating local oscillation optical signals;
the communication coherent receiver is used for receiving the forward optical signal sent by the transmitting end through the optical splitter and interfering with the local oscillation optical signal of the corresponding communication receiving end so as to coherently demodulate the optical signal to obtain demodulation signals of different users;
the communication processing module is used for extracting the multi-frequency sensing probe signals in the obtained demodulation signals, taking the sensing probe signals with corresponding frequencies as a communication synchronization head and carrying out frame synchronization on the digital subcarrier signals.
8. The integrated ventilation system according to any of claims 5-7, wherein the fiber laser is a narrow linewidth laser, the amplifier is a erbium doped fiber amplifier, and the splitter is a wavelength division multiplexer or a fiber coupler.
9. The integrated ventilation system of claim 8, wherein the sensing reception terminal comprises: a sensing coherent receiver and a sensing processing module;
the sensing coherent receiver is used for receiving the back Rayleigh scattering optical signal and interfering with the modulated multi-frequency local oscillation laser so as to coherently demodulate the back Rayleigh scattering optical signal to obtain a multi-frequency demodulation signal;
the sensing processing module is used for extracting multi-frequency sensing probe signals in a plurality of demodulation signals obtained by the sensing coherent receiver so as to sense the state of the optical fiber link.
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