A sense-through-the-wall system based on OFDM modulation format

Abstract

The application relates to a sensing and communication integrated system based on an OFDM modulation format, which comprises an OFDM laser generator, a broadband light generator, a first coupler, a micro-ring resonator, a second coupler and a receiving end. The OFDM laser generator generates laser with an OFDM signal, the broadband light generator generates broadband light, the first coupler is connected with the OFDM laser generator and the broadband light generator, and the laser with the OFDM signal and the broadband light are coupled. The micro-ring resonator is connected with the first coupler through a first optical fiber, and the laser with the OFDM signal and the broadband light carrying sensing information are superimposed into superimposed light. The second coupler is connected with the through end of the micro-ring resonator through a second optical fiber, and the superimposed light is split. The receiving end is connected with the second coupler, and the superimposed light is analyzed. The application can solve the problem that, in the related art, for a single carrier system, a sensing signal embedded into a communication network for realizing a sensing function usually has negative effects on optical communication signals, such as reducing communication quality.

Description

Technical Field

[0001] This application relates to the fields of optical fiber communication and sensing, and in particular to an integrated sensing and communication system based on OFDM modulation format. Background Technology

[0002] The sixth-generation (6G) mobile communication system requires communication equipment and systems to have the ability to sense the physical world, i.e., sensor-communication integration. However, there is currently no mature and specific implementation plan for sensor-communication integration. Microring resonators are considered to be one of the most attractive silicon-based photonic devices in optical sensing and communication applications, and can be embedded into traditional communication networks to achieve sensor-communication integration.

[0003] However, for single-carrier systems, the sensing signals embedded in the communication network to achieve sensing functions often have negative effects on the optical communication signals themselves, such as reducing communication quality. Summary of the Invention

[0004] This application provides an integrated sensing and communication system based on OFDM modulation format to solve the problem in related technologies that, for single-carrier systems, the sensing signals embedded in the communication network to realize sensing functions usually have a negative impact on the optical communication signal itself, such as reducing communication quality.

[0005] This application provides an integrated sensing system based on OFDM modulation format, comprising:

[0006] OFDM laser generator, which is used to generate laser with OFDM signal;

[0007] A broadband light generator, used to generate broadband light;

[0008] The first coupler is connected to the OFDM laser generator and the broadband light generator, and is used to couple the laser with OFDM signal and the broadband light.

[0009] A microring resonator is connected to the first coupler via a first optical fiber and is used to superimpose laser light with OFDM signal and broadband light carrying sensing information to form superimposed light.

[0010] The second coupler is connected to the through end of the microring resonator via a second optical fiber and is used to split the superimposed light.

[0011] The receiving end is connected to the second coupler and is used to analyze the superimposed light.

[0012] In some embodiments, the receiver includes a spectrometer for observing the spectrum and an optical receiver for signal demodulation.

[0013] In some embodiments, the OFDM laser generator includes a laser, and an OFDM optical carrier generator, an arbitrary waveform generator, and an IQ modulator connected in sequence, wherein the IQ modulator is connected to the laser and a first coupler.

[0014] In some embodiments, the OFDM laser generator further includes an intensity modulator connected between the IQ modulator and the laser.

[0015] In some embodiments, the broadband light generator includes a broadband light source connected to the first coupler.

[0016] In some embodiments, the broadband light generator further includes an optical filter connected between the broadband light source and the first coupler.

[0017] In some embodiments, an optical polarization controller is connected to the first optical fiber, and the optical polarization controller is located between the first coupler and the microring resonator.

[0018] In some embodiments, a first optical amplifier is connected to the first optical fiber, and the first optical amplifier is located between the first coupler and the microring resonator.

[0019] In some embodiments, a second optical amplifier is connected to the second optical fiber, and the second optical amplifier is located between the microring resonator and the second coupler.

[0020] In some embodiments, an optical attenuator is connected to the second optical fiber, and the optical attenuator is located between the microring resonator and the second coupler.

[0021] The beneficial effects of the technical solution provided in this application include:

[0022] This application can minimize the negative impact of sensing signals on communication signals. By embedding a micro-ring resonator as a sensor in an OFDM optical communication system, communication and real-time sensing can be achieved.

[0023] This application adopts the OFDM modulation format. The influence of the broadband optical resonant peak as sensing information on OFDM only includes one or a few subcarriers with superimposed resonant peaks, and has a small impact on the entire communication system. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A schematic diagram of an integrated sensing system based on OFDM modulation format provided in an embodiment of this application.

[0026] In the diagram: 1. OFDM laser generator; 2. Broadband optical generator; 3. First coupler; 4. Micro-ring resonator; 5. First optical fiber; 6. Second coupler; 7. Second optical fiber; 8. Spectrometer; 9. Optical receiver; 10. Laser; 11. OFDM optical carrier generator; 12. Arbitrary waveform generator; 13. IQ modulator; 14. Intensity modulator; 15. Broadband light source; 16. Optical filter; 17. Optical polarization controller; 18. First optical amplifier; 19. Second optical amplifier; 20. Optical attenuator. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] See Figure 1 As shown in the figure, this application provides a sensing and communication integrated system based on OFDM modulation format, which includes an OFDM laser generator 1, a broadband optical generator 2, a first coupler 3, a micro-ring resonator 4, a first optical fiber 5, a second coupler 6, a second optical fiber 7, and a receiving end. The OFDM laser generator 1 is used to generate laser light with OFDM signal; the broadband optical generator 2 is used to generate broadband light; the first coupler 3 is connected to the OFDM laser generator 1 and the broadband optical generator 2, and is used to couple the laser light with OFDM signal and the broadband light; the micro-ring resonator 4 is connected to the first coupler 3 through the first optical fiber 5, and is used to superimpose the laser light with OFDM signal and the broadband light carrying sensing information to form superimposed light; the second coupler 6 is connected to the through end of the micro-ring resonator 4 through the second optical fiber 7, and is used to split the superimposed light; the receiving end is connected to the second coupler 6, and is used to analyze the superimposed light.

[0029] The principle of this application is as follows:

[0030] Orthogonal Frequency Division Multiplexing (OFDM) is a multi-carrier modulation technique used in wireless and digital communication systems to transmit data, providing high-speed, high-capacity data transmission. OFDM divides the channel into several orthogonal sub-channels, splitting the high-speed data stream into multiple independent subcarriers with lower data rates, and modulating them onto each sub-channel for transmission. Each subcarrier is orthogonal (i.e., perpendicular to each other). The orthogonal subcarriers can be modulated and demodulated using Fast Fourier Transform (FFT) / I-FFT. Each subcarrier has an integer number of carrier cycles within one symbol time. The spectral nulls of each subcarrier overlap with those of adjacent subcarriers, meaning there is little or no mutual interference between them, or the mutual interference between subcarriers in the sub-channel is reduced. Furthermore, due to the partial overlap between subcarriers, it has higher bandwidth utilization than other modulation formats. Therefore, OFDM is resistant to inter-symbol interference, and channel equalization is relatively easy to achieve. Each subcarrier can transmit data at a lower rate, thus reducing the signal complexity on each subcarrier. This frequency separation characteristic makes OFDM robust to frequency-selective fading and multipath interference.

[0031] Therefore, this application employs Orthogonal Frequency Division Multiplexing (OFDM) technology. An OFDM laser generator 1 generates a laser with an OFDM signal, which is coupled into the first optical fiber 5 along with broadband light. A microring resonator 4, acting as a sensor in the measured environment, receives the signal through it. The direct-through end of the microring resonator 4 is used as the output. The signal passing through the direct-through end of the microring resonator 4 is a superposition of the laser with the OFDM signal and the broadband light carrying sensing information. Since the information fed back from the measured environment includes various parameters such as temperature, refractive index, or seawater salinity, this is reflected in the microring resonator 4 as a continuous spectrum containing resonance peaks in the broadband light output from its direct-through end. As the measured environment changes, these resonance peaks shift. Finally, signal demodulation is performed at the receiving end to calibrate the sensing information.

[0032] Although the resonance peak of sensor information affects the bit error rate of communication signals, the impact of the resonance peak is limited to one or a few subcarriers superimposed by the resonance peak due to the advantages of Orthogonal Frequency Division Multiplexing (OFDM).

[0033] (1) Orthogonal Frequency Division Multiplexing (OFDM) technology can continuously monitor sudden changes in communication characteristics on the transmission medium. Since the data transmission capability of the communication path changes over time, OFDM can dynamically adapt to it and connect and disconnect the corresponding carriers to ensure continuous and successful communication.

[0034] (2) Orthogonal Frequency Division Multiplexing (OFDM) technology can automatically detect which specific carrier in the transmission medium has high signal attenuation or interference pulses, and then take appropriate modulation measures to enable the carrier at the specified frequency to communicate successfully.

[0035] (3) The greatest advantage of Orthogonal Frequency Division Multiplexing (OFDM) technology is its ability to combat frequency-selective fading or narrowband interference. In a single-carrier system, a single fading or interference event can cause the entire communication link to fail, but in a multi-carrier system, only a small portion of the carriers will be affected by interference. Error correction codes can also be used to correct errors in these sub-channels.

[0036] (4) Orthogonal Frequency Division Multiplexing (OFDM) technology can effectively combat interference between signal waveforms and is suitable for high-speed data transmission in multipath environments and fading channels. When frequency selective fading occurs in the channel due to multipath transmission, only the subcarriers falling in the frequency band dips and the information they carry are affected, while other subcarriers are not damaged. Therefore, the overall bit error rate performance of the system is much better.

[0037] (5) Orthogonal Frequency Division Multiplexing (OFDM) technology has strong anti-fading capability through joint coding of each subcarrier. OFDM technology itself has already utilized the frequency diversity of the channel, so if the fading is not particularly severe, there is no need to add a time-domain equalizer. By jointly coding each channel, the system performance can be improved.

[0038] (6) Orthogonal Frequency Division Multiplexing (OFDM) technology is highly resistant to narrowband interference because these interferences only affect a small portion of the sub-channels.

[0039] Because Orthogonal Frequency Division Multiplexing (OFDM) technology can automatically detect which specific carrier in the transmission medium has high signal attenuation or interference pulses, it can determine the location of the resonance peak and thus deduce the sensing parameters. For communication signals superimposed with resonance peaks, this small portion of the carrier will be interfered with. If demodulating this part of the data is too difficult, packet loss can be considered to minimize the impact on the entire system.

[0040] Therefore, this application can minimize the negative impact of sensing signals on communication signals. By embedding a micro-ring resonator as a sensor in an OFDM optical communication system, communication and real-time sensing can be achieved.

[0041] This application adopts the OFDM modulation format. The influence of the broadband optical resonant peak as sensing information on OFDM only includes one or a few subcarriers with superimposed resonant peaks, and has a small impact on the entire communication system.

[0042] See Figure 1As shown, as a preferred example, the receiving end includes a spectrometer 8 for observing the spectrum and an optical receiver 9 for signal demodulation. The spectrometer 8 allows for very intuitive observation of spectral changes, thereby calibrating the sensing information.

[0043] See Figure 1 As shown, as a preferred example, the OFDM laser generator 1 includes a laser 10, and an OFDM optical carrier generator 11, an arbitrary waveform generator 12, and an IQ modulator 13 connected in sequence. The IQ modulator 13 is connected to the laser 10 and the first coupler 3. The IQ modulator 13 and the laser 10 are connected via an intensity modulator 14.

[0044] The OFDM optical carrier generator 11 generates an ODFM digital signal. The arbitrary waveform generator 12 converts the digital signal into an RF electrical signal to drive the IQ modulator. The IQ modulator modulates the electrical signal onto the light to complete the photoelectric conversion. The intensity modulator 14 generates multiple subcarriers.

[0045] The laser emitted by the laser 10 serves as a communication light source. After passing through the intensity modulator 14 and the IQ modulator 13 loaded with signals generated by the OFDM optical carrier generator 11 and the arbitrary waveform generator 12, a modulated optical signal is obtained, which is a laser with an OFDM signal.

[0046] See Figure 1 As shown, as a preferred example, the broadband light generator 2 includes a broadband light source 15 connected to the first coupler 3. The broadband light source 15 is connected to the first coupler 3 via an optical filter 16.

[0047] The broadband light generated by the broadband light source 15 is filtered out by the optical filter 16 to produce broadband light of a specific wavelength suitable for sensing.

[0048] The laser with OFDM signal is then coupled together with the filtered broadband light suitable for sensing through the first coupler 3.

[0049] See Figure 1 As shown, in a preferred example, an optical polarization controller 17 is connected to the first optical fiber 5, and the optical polarization controller 17 is located between the first coupler 3 and the microring resonator 4. A first optical amplifier 18 is connected to the first optical fiber 5, and the first optical amplifier 18 is located between the first coupler 3 and the microring resonator 4.

[0050] As a preferred embodiment, the optical polarization controller 17 and the first optical amplifier 18 are arranged sequentially along the optical transmission direction.

[0051] The laser with OFDM signal and the filtered broadband light suitable for sensing are coupled together through the first coupler 3, and after the polarization is adjusted by the optical polarization controller 17, they enter the first optical amplifier 18 for amplification and then enter the micro-ring resonator 4.

[0052] See Figure 1 As shown, in a preferred example, a second optical amplifier 19 is connected to the second optical fiber 7, and the second optical amplifier 19 is located between the micro-ring resonator 4 and the second coupler 6. An optical attenuator 20 is connected to the second optical fiber 7, and the optical attenuator 20 is located between the micro-ring resonator 4 and the second coupler 6.

[0053] As a preferred embodiment, the second optical amplifier 19 and the optical attenuator 20 are arranged sequentially along the optical transmission direction.

[0054] The laser with OFDM signal and the broadband light carrying sensing information output from the direct-through end of the micro-ring resonator 4 are amplified by the second optical amplifier 19, then enter the optical attenuator 20 for optical power attenuation, and then are split by the second coupler 6. One part enters the spectrometer 8 to observe the spectrum, and the other part enters the optical receiver 9 for signal reception and decoding.

[0055] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0056] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0057] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A sensing and communication integrated system based on OFDM modulation format, characterized in that, It includes: OFDM laser generator (1), which is used to generate laser with OFDM signal; A broadband light generator (2) is used to generate broadband light; The first coupler (3) is connected to the OFDM laser generator (1) and the broadband light generator (2) and is used to couple the laser with OFDM signal and the broadband light. The micro-ring resonator (4) is connected to the first coupler (3) through the first optical fiber (5) and is used to superimpose the laser with OFDM signal and the broadband light carrying sensing information to form superimposed light. The second coupler (6) is connected to the through end of the micro-ring resonator (4) via the second optical fiber (7) and is used to split the superimposed light. The receiving end is connected to the second coupler (6) and is used to analyze the superimposed light.

2. The integrated sensing system based on OFDM modulation format as described in claim 1, characterized in that: The receiving end includes a spectrometer (8) for observing the spectrum and an optical receiver (9) for signal demodulation.

3. The inductive communication system based on OFDM modulation format as described in claim 1, characterized in that: The OFDM laser generator (1) includes a laser (10), and an OFDM optical carrier generator (11), an arbitrary waveform generator (12), and an IQ modulator (13) connected in sequence. The IQ modulator (13) is connected to the laser (10) and the first coupler (3).

4. The inductive communication system based on OFDM modulation format as described in claim 3, characterized in that: The OFDM laser generator (1) also includes an intensity modulator (14) connected between the IQ modulator (13) and the laser (10).

5. The inductive communication system based on OFDM modulation format as described in claim 1, characterized in that: The broadband light generator (2) includes a broadband light source (15) connected to the first coupler (3).

6. The inductive communication system based on OFDM modulation format as described in claim 5, characterized in that: The broadband light generator (2) further includes an optical filter (16), which is connected between the broadband light source (15) and the first coupler (3).

7. The inductive communication system based on OFDM modulation format as described in claim 1, characterized in that: A polarization controller (17) is connected to the first optical fiber (5), and the polarization controller (17) is located between the first coupler (3) and the micro-ring resonator (4).

8. The inductive communication system based on OFDM modulation format as described in claim 1, characterized in that: A first optical amplifier (18) is connected to the first optical fiber (5), and the first optical amplifier (18) is located between the first coupler (3) and the micro-ring resonator (4).

9. The inductive communication system based on OFDM modulation format as described in claim 1, characterized in that: A second optical amplifier (19) is connected to the second optical fiber (7), and the second optical amplifier (19) is located between the micro-ring resonator (4) and the second coupler (6).

10. The inductive communication system based on OFDM modulation format as described in claim 1, characterized in that: An optical attenuator (20) is connected to the second optical fiber (7), and the optical attenuator (20) is located between the micro-ring resonator (4) and the second coupler (6).

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