CN116800338A - Underwater turbulence-resistant wireless optical communication system based on quasi-coherent modulation technology - Google Patents
Underwater turbulence-resistant wireless optical communication system based on quasi-coherent modulation technology Download PDFInfo
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- CN116800338A CN116800338A CN202310804516.0A CN202310804516A CN116800338A CN 116800338 A CN116800338 A CN 116800338A CN 202310804516 A CN202310804516 A CN 202310804516A CN 116800338 A CN116800338 A CN 116800338A
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- 238000004891 communication Methods 0.000 title claims abstract description 25
- 230000003287 optical effect Effects 0.000 title claims abstract description 22
- 238000005516 engineering process Methods 0.000 title abstract description 9
- 230000001427 coherent effect Effects 0.000 claims abstract description 5
- 238000006243 chemical reaction Methods 0.000 claims description 12
- 230000005540 biological transmission Effects 0.000 claims description 7
- 238000001914 filtration Methods 0.000 claims description 4
- 238000000034 method Methods 0.000 claims description 3
- 230000000694 effects Effects 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 3
- 230000006870 function Effects 0.000 description 3
- 101100316860 Autographa californica nuclear polyhedrosis virus DA18 gene Proteins 0.000 description 2
- 239000013535 sea water Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 239000003643 water by type Substances 0.000 description 1
Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/25—Arrangements specific to fibre transmission
- H04B10/2575—Radio-over-fibre, e.g. radio frequency signal modulated onto an optical carrier
- H04B10/25752—Optical arrangements for wireless networks
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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
- H04B10/50—Transmitters
- H04B10/516—Details of coding or modulation
- H04B10/548—Phase or frequency modulation
- H04B10/556—Digital modulation, e.g. differential phase shift keying [DPSK] or frequency shift keying [FSK]
- H04B10/5563—Digital frequency modulation
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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
- H04B10/60—Receivers
- H04B10/61—Coherent receivers
- H04B10/616—Details of the electronic signal processing in coherent optical receivers
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B13/00—Transmission systems characterised by the medium used for transmission, not provided for in groups H04B3/00 - H04B11/00
- H04B13/02—Transmission systems in which the medium consists of the earth or a large mass of water thereon, e.g. earth telegraphy
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
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Abstract
An underwater turbulence-resistant wireless optical communication system based on a quasi-coherent modulation technology relates to the technical field of wireless communication, and solves the problems that the prior art has poor ocean turbulence-resistant effect, can not inhibit the jitter of the intensity of a received signal caused by turbulence, and can not recover a baseband signal according to the intensity of the signal under the emergency of a receiving end, and a transmitting unit and a receiving unit; the transmitting unit comprises a first analog-to-digital converter, a transmitting end FPGA, a first digital-to-analog converter and a light source driver; the receiving unit comprises an APD photoelectric detector, a second analog-to-digital converter, a receiving end FPGA and a second digital-to-analog converter; the invention can control the luminous intensity of the light source through a quasi-coherent modulation technology, namely, the signal source is utilized to carry out frequency modulation on the baseband signal by using the FPGA, so that the luminous intensity of the light source is sinusoidal, the frequency is controlled by the signal source, the receiving end carries out coherent demodulation by using the FPGA, and the baseband signal is recovered according to the signal frequency and is not influenced by the signal intensity.
Description
Technical Field
The invention relates to the technical field of wireless communication, in particular to an underwater turbulence-resistant wireless optical communication system based on a quasi-coherent modulation technology.
Background
When the optical signal is transmitted underwater, the optical signal can be influenced by underwater turbulence, so that the transmission performance of the optical signal is reduced. Wherein underwater turbulence is random fluctuations in refractive index caused by changes in seawater salinity and temperature. The light beam can cause light intensity flicker after passing through an underwater turbulence channel, so that the light power of a receiving end is dithered, and the signal error rate is increased. In the atmosphere channel, the optical power jitter caused by the atmosphere turbulence is suppressed by adopting a coherent communication system. In underwater wireless optical communication, in order to improve the transmission performance of optical signals, a modulation technique may be used to achieve this object.
See literature: wangT, et al 15Mbpsun waters wireless optical communications basedonacousto-optical modularandNRZ-OOKmodule [ J ]. Optics & Laser Technology,2022,150:107943. Its structure is shown in FIG. 1, a schematic diagram of a high-rate remote underwater Laser communication system. The specific structure is that the computer 12 generates a pseudo-random binary sequence, and uploads the pseudo-random binary sequence to the programmable gate array FPGA5, and then the data signals generated by the FPGA are loaded onto the driver 4. While the beam from the laser 1 passes through the convex lens 2 to the acousto-optic modulator 6, then the beam is focused on the photodiode PIN10 through the lens 7, the underwater channel 8 and the converging lens 9, and the detected electrical signal is captured by the digital oscilloscope 11 and then sent to the computer 12 for further processing. The system enables high-rate close-range laser communication based on a 520nm laser diode using an NRZ-OOK modulated AOM. However, the system does not consider the influence of ocean turbulence, and the modulation format used is easy to deform under the influence of ocean turbulence, so that the problem of received signal strength jitter caused by turbulence cannot be restrained.
Disclosure of Invention
The invention provides an underwater turbulence-resistant wireless optical communication system based on quasi-coherent modulation, which aims to solve the problems that the prior art has poor turbulence-resistant effect and cannot inhibit the jitter of the intensity of a received signal caused by turbulence and cannot recover a baseband signal according to the intensity of the signal under the sudden condition of a receiving end.
An underwater turbulence-resistant wireless optical communication system based on quasi-coherent modulation comprises a transmitting unit and a receiving unit;
the transmitting unit comprises a first analog-to-digital converter, a transmitting end FPGA, a first digital-to-analog converter and a light source driver;
the receiving unit comprises an APD photoelectric detector, a second analog-to-digital converter, a receiving end FPGA and a second digital-to-analog converter;
the method comprises the steps that an analog signal source is subjected to analog-to-digital conversion by a first analog-to-digital converter and then is transmitted to a transmitting end FPGA, a digital frequency modulation signal generated after frequency modulation is carried out by the transmitting end FPGA is transmitted to a first digital-to-analog converter, the first digital-to-analog converter transmits the analog frequency modulation signal to a light source driver, the light source driver drives a light source to emit light, the light source is controlled to emit light intensity, and the light intensity becomes a sine change signal to be a quasi-coherent modulation signal;
the light source outputs a light signal which is transmitted through an underwater channel and reaches the receiving end on the photosensitive surface of the APD photoelectric detector, photoelectric conversion of the light signal is completed by the APD photoelectric detector, the output electric signal is transmitted to the receiving end FPGA for coherent demodulation and filtering after being subjected to analog-to-digital conversion by the second analog-to-digital converter, and the demodulated digital signal is taken as an original signal sent by a signal source after being subjected to digital-to-analog conversion by the second digital-to-analog converter, so that wireless data transmission is realized.
The invention has the beneficial effects that:
(1) The turbulence resistance is strong: the luminous intensity of the light source can be controlled by a quasi-coherent modulation technology, namely, the signal source is utilized to carry out frequency modulation on the baseband signal by using the FPGA, so that the luminous intensity of the light source is sinusoidal, the frequency is controlled by the signal source, the receiving end carries out coherent demodulation by using the FPGA, and the baseband signal is recovered according to the signal frequency and is not influenced by the signal intensity.
The problem of received signal strength jitter caused by light intensity flicker caused by underwater turbulence is solved, the influence of the underwater turbulence on signals is effectively restrained, and the performance of an underwater wireless optical communication system is improved.
(2) The transmission distance is far: the intensity jitter of the signal at the receiving end is restrained by using a quasi-coherent modulation technology, the optical power loss is slower, and the transmission distance is longer. The underwater turbulence-resistant wireless optical communication system based on the quasi-coherent modulation technology has wide application prospect in the field of sea water channel long-distance communication.
Drawings
FIG. 1 is a schematic diagram of a conventional high-rate remote underwater laser communication system.
Fig. 2 is a schematic diagram of an underwater turbulence-resistant wireless optical communication system based on quasi-coherent modulation according to the present invention.
Detailed Description
Referring to fig. 2, the underwater turbulence-resistant wireless optical communication system based on the quasi-coherent modulation of the present embodiment includes a signal source 13, a first analog-to-digital converter (AD) 14, a transmitting end FPGA15, a first digital-to-analog converter (DA) 16, a light source driver 17, a light source 18, a collimating lens 19, an underwater channel 20, a converging lens 21, an APD photodetector 22, a second analog-to-digital converter (AD) 23, a receiving end FPGA24, and a second digital-to-analog converter (DA) 25. The function of the transmitting end FPGA15 is to implement frequency modulation of the signal source digital signal through hardware description language programming, and the function of the receiving end FPGA24 is to implement demodulation and filtering functions of the frequency modulated signal through hardware description language programming.
The signal source 13 is an analog signal, and is connected to the input end of the first AD14 through a cable to complete analog-to-digital conversion, the converted digital signal is sent to the transmitting end FPGA15 through the output end of the first AD14, frequency modulation is achieved by the transmitting end FPGA15, the generated digital frequency modulation signal is output to the first DA16, the digital frequency modulation signal is converted into an analog frequency modulation signal through the first DA16 and is transmitted to the light source driver 17, the light source driver 17 drives the light source 18 to emit light, and therefore the light source 18 emits light intensity is controlled, and the light intensity change is the quasi-coherent modulation signal.
The light signal output by the light source 18 is collimated into parallel light by the collimator 19, the parallel light reaches the receiving end after being transmitted by the underwater channel 20, the light beam is focused by the converging lens 21 and then is converged on the photosensitive surface of the photoelectric detector APD22, the photoelectric conversion of the light signal is completed by the photoelectric detector 22, the analog-to-digital conversion of the output electric signal is completed by the second AD23, the electric signal is transmitted to the receiving end FPGA24, the demodulation and the filtering are carried out by the receiving end FPGA24, the digital signal after the demodulation is subjected to the digital-to-analog conversion by the second DA25, and the analog signal output by the second DA25 is the original signal sent by the signal source 13. The wireless data transmission of the electric signal-optical signal-electric signal under water is realized generally.
The invention can obtain the long-distance turbulence-resistant underwater wireless optical communication system, and can obtain a more reliable communication system with longer distance along with the continuous development of various photoelectric components, and the application of the system is wider.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.
Claims (3)
1. The underwater turbulence-resistant wireless optical communication system based on the quasi-coherent modulation is characterized in that: the communication system includes a transmitting unit and a receiving unit;
the transmitting unit comprises a first analog-to-digital converter, a transmitting end FPGA, a first digital-to-analog converter and a light source driver;
the receiving unit comprises an APD photoelectric detector, a second analog-to-digital converter, a receiving end FPGA and a second digital-to-analog converter;
the method comprises the steps that an analog signal source is subjected to analog-to-digital conversion by a first analog-to-digital converter and then is transmitted to a transmitting end FPGA, a digital frequency modulation signal generated after frequency modulation is carried out by the transmitting end FPGA is transmitted to a first digital-to-analog converter, the first digital-to-analog converter transmits the analog frequency modulation signal to a light source driver, the light source driver drives a light source to emit light, the light source is controlled to emit light intensity, and the light intensity becomes a sine change signal to be a quasi-coherent modulation signal;
the light source outputs a light signal which is transmitted through an underwater channel and reaches the receiving end on the photosensitive surface of the APD photoelectric detector, photoelectric conversion of the light signal is completed by the APD photoelectric detector, the output electric signal is transmitted to the receiving end FPGA for coherent demodulation and filtering after being subjected to analog-to-digital conversion by the second analog-to-digital converter, and the demodulated digital signal is taken as an original signal sent by a signal source after being subjected to digital-to-analog conversion by the second digital-to-analog converter, so that wireless data transmission is realized.
2. The underwater turbulence resistant wireless optical communication system based on the quasi-coherent modulation of claim 1, wherein: the transmitting unit also comprises a collimating lens, and the light signal output by the light source is collimated into parallel light by the collimating lens and transmitted by the underwater channel to reach the receiving end.
3. The underwater turbulence resistant wireless optical communication system based on the quasi-coherent modulation of claim 1, wherein: the receiving unit also comprises a converging lens, and the light beam is converged on the photosensitive surface of the APD photoelectric detector after being focused by the converging lens.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310804516.0A CN116800338A (en) | 2023-07-03 | 2023-07-03 | Underwater turbulence-resistant wireless optical communication system based on quasi-coherent modulation technology |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310804516.0A CN116800338A (en) | 2023-07-03 | 2023-07-03 | Underwater turbulence-resistant wireless optical communication system based on quasi-coherent modulation technology |
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| CN116800338A true CN116800338A (en) | 2023-09-22 |
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| CN202310804516.0A Pending CN116800338A (en) | 2023-07-03 | 2023-07-03 | Underwater turbulence-resistant wireless optical communication system based on quasi-coherent modulation technology |
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2023
- 2023-07-03 CN CN202310804516.0A patent/CN116800338A/en active Pending
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