Transmission system based on underwater blue-green optical communication

Abstract

The utility model belongs to the technical field of wireless communication, and discloses a transmission system based on underwater blue-green optical communication, and a transmitting terminal is composed of an Ethernet module, an FPGA information processing module, an LED driving module, an LED array, a photoelectric conversion module, a signal amplification processing circuit, an RS coding and decoding module and a computer. The receiving end comprises an optical filter and an aspheric receiving lens, a received optical signal is received by a photomultiplier tube (PMT) photoelectric detector, the received optical signal is subjected to photoelectric conversion and then input to a signal amplification processing circuit to obtain an LVTTL level pulse sequence, the LVTTL level pulse sequence is demodulated and decoded by an FPGA receiving module to recover information, and the information is sent to upper computer software through an Ethernet module. And finally, the computer analyzes and processes related information. Compared with underwater sound wave communication and underwater electromagnetic communication, the underwater sound wave communication device has the characteristics of high bandwidth, low power consumption, small size and the like.

Description

TECHNICAL FIELD

[0001] The utility model belongs to but is not limited to wireless communication technical field, especially relates to a transmission system based on underwater blue green light communication. BACKGROUND

[0002] Underwater wireless communication is important in the ocean by using underwater sensors, robots to collect data, and through underwater real-time communication system to collect information. There are three main ways of underwater wireless communication: underwater electromagnetic wave communication, underwater acoustic wave communication and underwater optical communication. Underwater electromagnetic wave communication uses ultra-low frequency (30-3000Hz) electromagnetic wave to transmit information, but electromagnetic wave attenuates seriously in water. Underwater acoustic wave communication has long delay and low transmission rate. Acoustic wave communication in seawater has low speed, is easily affected by turbulence and biology, and has long communication delay when multi-path effect occurs. Different frequency acoustic wave communication easily causes inter-symbol interference. Underwater optical communication technology is a new technology favored by researchers in recent years. Compared with electromagnetic wave and acoustic wave communication, underwater optical communication technology has high communication rate, large transmission capacity, low device power consumption, small size, good communication confidentiality, high security and other advantages. Most of the current underwater LED communication research is based on small power LED as the research object, uses different modulation technology to realize high-speed communication, but its transmission power is small, the communication distance is short, and it is not suitable for engineering field. Most of the high-power LED underwater optical communication research has complex circuit structure and low communication rate, and cannot be applied in actual engineering. CONTENT OF THE UTILITY MODEL

[0003] In view of the problems existing in the prior art, the utility model provides a transmission system based on underwater blue green light communication.

[0004] The utility model is realized in this way, a transmission system based on underwater blue green light communication, the system includes transmitting end and receiving end;

[0005] The transmitting end specifically includes:

[0006] The transmitting end PC end is the interface of user operation, and is used for inputting, editing and sending data. The user converts the information to be transmitted into digital signals through the application program or software of the PC end, so as to provide original data for the subsequent communication process.

[0007] The Ethernet module is connected with the PC end, is responsible for converting the digital signals output by the PC end into a format suitable for network transmission, and sends the signals to the FPGA information processing module through the Ethernet cable. It ensures the efficient and reliable transmission of data in the transmitting end.

[0008] FPGA information processing module, connected with Ethernet module, FPGA (Field Programmable Gate Array) is a highly integrated programmable logic device, used for encoding, modulation and other processing of received digital signals to adapt to the specific requirements of underwater optical communication; FPGA can be flexibly configured to optimize communication performance, such as improving data transmission rate, reducing error rate, etc.

[0009] Bias_T bias module, connected with FPGA information processing module, used to provide stable DC bias current for LED array module; this bias current is necessary for LED light emission, which ensures that LED can work with stable light intensity, thereby improving the reliability and stability of communication;

[0010] Constant current source module, connected with Bias_T bias module, used to further ensure that LED array module obtains precisely controlled current supply; it can maintain stable output of current, even in the case of input voltage fluctuation, to ensure that the light intensity of LED is not affected, which is crucial for maintaining communication quality;

[0011] LED array module, connected with Bias_T bias module, is one of the core components of the sending end, which converts processed electrical signals into optical signals; the design and optimization of LED array are crucial for improving the transmission distance, rate and energy efficiency of optical communication;

[0012] Transmitting end optical module, connected with LED array module, is responsible for focusing, collimating and coupling the light signals emitted by LED array to ensure that the light signals can be efficiently transmitted into the underwater channel; it may include lenses, fiber couplers and other optical elements;

[0013] The receiving end specifically includes:

[0014] Receiving end optical module, connected with transmitting end optical module, is responsible for capturing light signals transmitted from the underwater channel and guiding them to PMT photodetector module; it may include receiving lenses, optical filters and other elements to improve the sensitivity and selectivity of signal reception;

[0015] PMT photodetector module, connected with receiving end optical module, PMT (Photomultiplier Tube) is a high-sensitivity photoelectric converter device that can convert received light signals into electrical signals; PMT has high gain, low noise and other characteristics, and is a commonly used photodetector in underwater optical communication;

[0016] Signal amplification and processing circuit module, connected with PMT photodetector module, used to amplify and preprocess the weak electrical signals output by PMT to improve the signal-to-noise ratio and anti-interference ability of the signal; this circuit mainly includes amplifiers, comparators and other elements;

[0017] The FPGA information processing module is connected with the signal amplification processing circuit module, and is responsible for decoding and demodulating the received electrical signal to restore the original digital signal at the receiving end.

[0018] The Ethernet module is connected with the FPGA information processing module, converts the restored digital signal into a format suitable for network transmission, and sends the signal to the PC end through an Ethernet cable; it ensures efficient and reliable transmission of data within the receiving end.

[0019] The receiving end PC end is connected with the Ethernet module, and is used as an interface for user operation at the receiving end to receive, display and process data transmitted from the underwater channel; the user can view and analyze the received information through the application program or software of the PC end.

[0020] Further, the chip in the Ethernet module is YT8511, which has low cost, low power consumption and can adapt to 100M / 1000M network ports.

[0021] Further, the FPGA information processing module uses FPGA as the main control core, and the model is XC7Z020-2CLG400I, which has powerful processing performance and abundant resources.

[0022] Further, the RF amplifier chip in the Bias_T bias module is HMC788ALP2ETR, which has a super-wide frequency range and large gain.

[0023] Further, the constant current source module is built by discrete components NMOS tubes, and the model of the NMOS tube is NTR5198NL.

[0024] Further, the LED array is composed of six LEDs, all with a wavelength of 450nm, an array electric power of 18W and a light power of 2W.

[0025] Further, the transmitting end optical module mainly uses an aluminum alloy condensing cup to concentrate light energy, making the light information transmission farther.

[0026] The receiving end optical module is composed of a filter and a lens, wherein the filter is used to filter out non-communication light and interference light source, and the model is NP525; the lens is used to focus light energy, making the received light energy higher, and the model is LBW30.

[0027] Further, the PMT photoelectric detection module is used as a core device of the underwater optical communication system, and converts the optical signal into a weak all-electric signal.

[0028] Further, the signal amplification and processing circuit module mainly realizes amplification and shaping processing on the electric signal output by the photoelectric detector, the amplifier chip signal is OPA657, and the shaping chip model is max999.

[0029] In combination with the technical scheme and the solved technical problems, the technical scheme to be protected has the advantages and positive effects that:

[0030] The transmission system based on underwater blue-green light communication adopts modular design, is composed of a transmitting end and a receiving end, and cooperatively works of the modules to realize efficient data transmission. The transmitting end comprises a PC end, an Ethernet module, an FPGA signal processing unit, a Bias_T bias circuit, a constant current source driving circuit, an LED array light source and an optical transmitting system, and is used for converting an input digital signal into a high-power blue-green light signal and collimating and emitting. The receiving end is composed of an optical receiving module, a PMT photoelectric detector, a signal amplification and processing circuit, an FPGA decoding module and an Ethernet data transmission unit, is responsible for capturing the underwater blue-green light signal, converting the underwater blue-green light signal into an electric signal, restoring original data after signal processing and transmitting the original data to an upper computer for analysis. The system adopts a 450nm wavelength LED array as a light source, matches a minimum attenuation window in water, and ensures a farther communication distance. Meanwhile, in combination with FPGA modulation and demodulation, error code correction and automatic gain control (AGC) algorithms, the communication quality is improved, and the error code rate is reduced.

[0031] The technical scheme breaks through the technical bottlenecks of acoustic wave communication, electromagnetic wave communication and traditional optical communication. Compared with acoustic wave communication, the data transmission rate of the system is improved by tens to hundreds of times, and the problems of low bandwidth, large time delay and environmental noise interference are overcome. Compared with electromagnetic wave communication, the blue-green light signal has lower loss in water and a farther propagation distance, and is not affected by salinity and temperature changes. Compared with single-wavelength optical communication, the blue-green light communication system adopts a high-power LED array, optical collimation technology and a high-sensitivity detector, greatly improves the light energy utilization rate, reduces signal attenuation, and realizes farther underwater data transmission.

[0032] The utility model discloses the optimization innovation in optical design, signal processing, data transmission stability etc. aspects: (1) adopt PMT photoelectric detection module (Hamamatsu H10721-20), provide high gain (maximum 106), low dark current, ensure the high -efficient conversion of weak signal of receiving end, (2) signal amplification processing module combines OPA657 amplification chip and MAX999 shaping chip, improves signal signal -to -noise ratio, effectively reduces the error rate, (3) FPGA (XC7Z020-2CLG400I) intelligent processing system, realizes high -speed signal modulation and demodulation, automatic gain control, error correction, guarantees data transmission stability, (4) adopt aluminum alloy spotlight cup and optical filter (NP525), enhance the light energy focusing ability of transmitting end, improve the anti -interference ability of receiving end, optimize system overall communication performance.

[0033] The underwater blue-green light communication system has wide application prospects in many fields, including underwater sensor networks, ocean engineering, diving equipment communication, autonomous underwater vehicle (AUV) data transmission, submarine monitoring and military security applications. In underwater detection, the system can realize high-speed, low-power data interaction of underwater sensors, meet the distributed underwater monitoring requirements; in AUV and surface platform communication, it can provide a large bandwidth, low-latency data link to improve the collaborative operation capability of autonomous underwater robots; in ocean engineering and military communication, it can realize low-detectability, high-security underwater optical communication. The utility model solves the problems of low underwater communication rate, high error rate and limited transmission distance through high-power LED, FPGA intelligent processing, PMT high-sensitivity detection and optical optimization, and provides a new development direction for future efficient and stable underwater optical communication technology. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is the transmission system structure diagram provided by the utility model embodiment based on underwater blue-green light communication;

[0035] Figure 2 is the structure diagram of spotlight cup provided by the utility model embodiment.

[0036] Figure 3 is the system structure component diagram provided by the utility model embodiment.

[0037] Figure 4 is the whole system schematic diagram provided by the utility model embodiment.

[0038] Figure 3 In it, 1, ethernet module;2, FPGA information processing module;3, Bias_T bias module;4, LED array module;5, transmitting optical module;6, receiving optical module;7, signal amplification processing circuit module. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages of the utility model clearer and more apparent, the utility model will be further described in detail below in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and not to limit the utility model.

[0040] As Figure 1 , Figure 3 , Figure 4 Indicated, the utility model embodiment provides a kind of transmission system based on underwater blue-green light communication, and this system includes transmitting end and receiving end;

[0041] The transmitting end specifically includes:

[0042] Transmitting end PC end, user-operated interface, for input, editing and sending data;User converts the information needing transmission into digital signal through the application program or software of PC end, provides original data for subsequent communication process;

[0043] Ethernet module 1 is connected with PC end, is responsible for converting the digital signal output by PC end into format suitable for network transmission, and sends signal to FPGA information processing module 2 through Ethernet cable;It ensures the efficient and reliable transmission of data within the transmitting end;

[0044] FPGA information processing module 2 is connected with Ethernet module 1, and FPGA (Field Programmable Gate Array) is a kind of highly integrated programmable logic device, for encoding, modulation and other processing to the received digital signal, to adapt to the specific requirements of underwater optical communication;FPGA can be flexibly configured to optimize communication performance, such as improving data transmission rate, reducing error rate, etc.;

[0045] Bias_T bias module 3 is connected with FPGA information processing module 2, for providing stable DC bias current for LED array module 4;This bias current is necessary for LED light emission, which ensures that LED can work with stable light intensity, thereby improving the reliability and stability of communication;

[0046] Constant current source module is connected with Bias_T bias module 3, for further ensuring that LED array module 4 obtains precisely controlled current supply;It can maintain stable output of current, even in the case of input voltage fluctuation, the light intensity of LED can be guaranteed not to be affected, which is crucial for maintaining communication quality;

[0047] LED array module 4 is connected with Bias_T bias module 3, and it is one of the core components of transmitting end, which converts processed electrical signal into optical signal;The design and optimization of LED array are crucial for improving the transmission distance, rate and energy efficiency of optical communication;

[0048] Transmitting end optical module, connected with LED array module 4, is responsible for focusing, collimating and coupling the light signal emitted by the LED array to ensure that the light signal can be efficiently transmitted into the underwater channel; it may include lenses, optical fiber couplers and other optical elements;

[0049] The receiving end specifically includes:

[0050] Receiving end optical module, connected with the transmitting end optical module, is responsible for capturing the light signal transmitted from the underwater channel and guiding it to the PMT photodetector module; it may include receiving lenses, optical filters and the like to improve the sensitivity and selectivity of signal reception;

[0051] PMT photodetector module, connected with the receiving end optical module, is a high-sensitivity photoelectric conversion device that can convert the received light signal into an electrical signal; PMT has high gain, low noise and other characteristics, and is a commonly used photodetector in underwater optical communication;

[0052] Signal amplification and processing circuit module 7, connected with the PMT photodetector module, is used for amplifying and preprocessing the weak electrical signal output by the PMT to improve the signal-to-noise ratio and anti-interference ability of the signal; this circuit mainly includes amplifiers, comparators and other elements;

[0053] FPGA information processing module 2, connected with the signal amplification and processing circuit module 7, is responsible for decoding, demodulating and other processing of the received electrical signal in the receiving end to recover the original digital signal; similar to the FPGA in the transmitting end, the FPGA in the receiving end can also be flexibly configured to adapt to different communication needs;

[0054] Ethernet module 1, connected with the FPGA information processing module 2, converts the recovered digital signal into a format suitable for network transmission and sends the signal to the PC end through an Ethernet cable; it ensures efficient and reliable transmission of data within the receiving end;

[0055] Receiving end PC, connected with the Ethernet module 1, serves as the user's interface for receiving, displaying and processing data transmitted from the underwater channel in the receiving end; users can view and analyze the received information through the application program or software of the PC.

[0056] Ethernet module 1 receives the host computer Ethernet data packet, and the data is internally cached by FPGA, and is encoded by internal RS error correction encoder and 8B / 10B encoder, and then the LVTTL level signal is output to the LED driving circuit through parallel-serial conversion, wherein the LED driving circuit is composed of Bias-T and constant current source circuit to drive the LED array module 4; the light source is emitted into the underwater channel through the collimating optical lens. The receiving optical system includes a filter and an aspherical receiving lens, and the received light signal is received by a photomultiplier tube (PMT) photodetector, and after the received light signal is photoelectrically converted, it is input to the signal amplification processing circuit to obtain the LVTTL level pulse sequence, and then the information is recovered by the FPGA receiving module demodulation and decoding and sent to the host computer software through the Ethernet module 1, and finally the related information is analyzed and processed by the computer.

[0057] The chip in the Ethernet module 1 is YT8511, which has low cost, low power consumption and can adapt to 100M / 1000M network port.

[0058] The FPGA information processing module 2 uses FPGA as the main control core, and the model is XC7Z020-2CLG400I, which has powerful processing performance and rich resources.

[0059] The radio frequency amplifier chip in the Bias_T bias module 3 is HMC788ALP2ETR, which has the characteristics of super wide frequency range and large gain.

[0060] The constant current source module is built by discrete components NMOS tubes, and the NMOS tube model is NTR5198NL.

[0061] The LED array is composed of six LEDs, all with a wavelength of 450nm, an array electric power of 18W, and a light power of 2W.

[0062] As shown in Figure 2 The transmitting end optical module mainly uses an aluminum alloy light cup for gathering light energy to transmit light information to a farther distance.

[0063] The receiving end optical module is composed of a filter and a lens, wherein the filter is used to filter out non-communication light and interference light source, and the model is NP525; the lens is used to focus light energy, and the model is LBW30.

[0064] The PMT photodetection module is a core device of the underwater optical communication system, which converts optical signals into weak electrical signals, and the model is Hamamatsu H10721-20 photodetector, which has small dark current and the highest gain of 106, and the gain is adjustable.

[0065] The signal amplification processing circuit module 7 mainly realizes the amplification and shaping processing of the electrical signal output by the photoelectric detector, the amplifier chip signal is OPA657, and the shaping chip model is max999.

[0066] In this example, the Ethernet chip is YT8511, which has low cost, low power consumption and can adapt to 100M / 1000M network port. The information processing module uses FPGA as the main control core, the model is XC7Z020-2CLG400I, which has powerful processing performance and rich resources. The radio frequency amplifier chip in the Bias_T bias module is HMC788ALP2ETR , which has a super wide frequency range, large gain and other characteristics. The constant current source is built by discrete components NMOS tube, and the NMOS tube model is NTR5198NL. The LED array is composed of six LEDs, all with a wavelength of 450nm, an array electrical power of 18W, and a light power of 2W. The emission optical module mainly uses an aluminum alloy light cup for gathering light energy, making the light information transmission farther. The receiving optical module is composed of a filter and a lens, the filter is used to filter out non-communication light and interference light source, the model is NP525, and the lens is used to focus light energy, making the received light energy higher, the model is LBW30. The PMT photoelectric detection module is the core device of the underwater optical communication system, which converts optical signals into weak electrical signals, the model is Hamamatsu H10721-20 photodetector, with small dark current and maximum gain of 10 6 . The signal amplification processing circuit module mainly realizes the amplification and shaping processing of the electrical signal output by the photoelectric detector, the amplifier chip signal is OPA657, and the shaping chip model is max999.

[0067] The wavelength of blue-green light is between 450nm and 550nm. This band of light source has strong penetration ability and small attenuation degree under water, and has good underwater directivity, which is suitable for underwater long-distance transmission.

[0068] The design of this scheme drives the light source electrical power to be 18W and the light power to be 2W. Increasing the emission light power can effectively improve the underwater communication distance.

[0069] In example two, the structure is basically the same as that of example one, except that the wavelength of the LED light source is 470nm.

[0070] In example three, the structure is basically the same as that of example one, except that the wavelength of the LED light source is 525nm.

[0071] In example four, the structure is basically the same as that of example one, except that the wavelength of the LED light source is 560nm.

[0072] The above merely describes a specific implementation of the present application, but the protection scope of the present application is not limited thereto, any modification, equivalent replacement and improvement within the technical range disclosed by the present application, and within the spirit and principle of the present application, should be covered within the protection scope of the present application.

Claims

1. A transmission system based on underwater blue-green light communication, characterized in that, The system comprises a transmitting end and a receiving end, wherein the transmitting end comprises: (1) a transmitting end PC connected with an Ethernet module; (2) the Ethernet module connected with an FPGA information processing module; (3) the FPGA information processing module connected with a Bias_T biasing module; (4) the Bias_T biasing module connected with an LED array module and a constant current source module; (5) the constant current source module connected with the LED array module; (6) the LED array module connected with a transmitting end optical module; (7) the transmitting end optical module for projecting optical signals to an underwater channel. The receiving end comprises: (1) a receiving end optical module connected with a PMT photoelectric detection module; (2) the PMT photoelectric detection module connected with a signal amplification processing circuit module; (3) the signal amplification processing circuit module connected with an FPGA information processing module; (4) the FPGA information processing module connected with an Ethernet module; (5) the Ethernet module connected with a receiving end PC; (6) the receiving end PC for receiving and processing decoded data.

2. The underwater blue-green light communication based transmission system as claimed in claim 1, wherein, The Ethernet module adopts a YT8511 chip with adaptive 100M / 1000M network interface.

3. The underwater blue-green light communication based transmission system as claimed in claim 1, wherein, The FPGA information processing module adopts an FPGA device with model number XC7Z020-2CLG400I.

4. The underwater blue-green light communication based transmission system as claimed in claim 1, wherein, The Bias_T biasing module comprises a radio frequency amplifier chip HMC788ALP2ETR.

5. The underwater blue-green light communication based transmission system as claimed in claim 1, wherein, The LED array module comprises six LEDs with wavelength of 450 nm, array electric power of 18 W and optical power of 2 W.

6. The underwater blue-green light communication based transmission system as claimed in claim 1, wherein, The receiving end optical module comprises a filter with model number NP525 and a lens with model number LBW30.

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