56 results about "Underwater wireless optical communications" patented technology

The invention discloses an underwater LED (Light-Emitting Diode) long distance communication system based on a visible light. The system comprises a transmitting device and a receiving device which are arranged underwater and respectively used for performing waterproof packaging; the transmitting device specifically comprises a data acquisition module, a transmitting end digital signal processing module, a digital to analog conversion module, a transmitting end amplifier equalization module, a direct current bias module and a light source; the receiving device specifically comprises an optical receiving module, a receiving end amplifier equalization module, a filter module, an analog to digital conversion module, a receiving end digital signal processing module and a data recovery module. The underwater LED long distance communication system based on the visible light provided by the invention can overcome the attenuation influence of an underwater environment on an electromagnetic wave and the disadvantage of low speed and low bandwidth of a sound wave, improve the transmission rate, increase the data carrying capacity, enhance the security, reduce the interference effect, reduce the equipment cost and power consumption, and realize high speed, high bandwidth, high security, and anti-interference underwater wireless optical communication.

The invention relates to an underwater LED (light-emitting diode) visible light communication system. The underwater LED visible light communication system comprises a water-proof and sealed transmitting device and a water-proof and sealed receiving device which are placed underwater; the transmitting device comprises a light source and a control unit for modulating a light signal emitted by the light source according to information to be transmitted; and the receiving device comprises a light receiving unit for receiving the modulated light signal from the transmitting device, and a demodulating unit for demodulating the received modulated light signal so as to restore the transmitted information. According to the technical solution, by modulating the transmitted information into the light signal, underwater wireless optical communication is achieved, thus not only improving the transmission rate and reducing the size and attenuation, but also avoiding interference to a human body and surrounding electronic equipment and achieving dual functions of lighting and communication.

The invention discloses an intelligent underwater wireless optical communication system. A mechanism of self-adaptively detecting the channel environment by a receiver and the thought of updating a modulation coding format by a feedback sending end are introduced to overcome the defect that the traditional underwater visible optical communication system is confined to the limited rate of the limited scene, the receiver is more intelligent, the instant channel condition can be judged according to the statistic feature of the receiving signal, thereby making out a feedback opinion report to a sending device; the system is provided with the self-adaptive performance through the feedback channel, the stable work in the changed environment can be guaranteed, and the system has important significance for the actual application.

The invention relates to the field of underwater wireless optical communication and aims at providing an underwater wireless optical communication device and method based on a wavelength division multiplexing technology. The device comprises a transmitting end device and a receiving end device. The transmitting end device comprises a signal processor connected with three voltage amplifiers. Each voltage amplifier is connected with an adjustable attenuator, a bias drive module and a laser in sequence. The three lasers are red light, green light and blue light lasers and are connected with a three-in-one optical coupler. The three-in-one optical coupler is arranged opposite to a transmitting end lens. The receiving end device comprises a photoelectric detector arranged opposite to a receiving end lens. The photoelectric detector is connected with the voltage amplifiers, the adjustable attenuators and the signal processor in sequence. Red light, green light and blue light dichroic optical filters are placed on an optical path between the receiving end lens and the photoelectric detector. According to the device and the method, an applicable range of an underwater wireless optical communication system is greatly improved and the normal underwater wireless optical communication can be ensured all the time in different seawater environments.

The invention belongs to the technical field of visible light communication, and particularly relates to a nonlinear distortion compensation algorithm based on K-DNN and a visible light communicationdevice. The method provides a nonlinear distortion compensation algorithm, and comprises the following steps: converting a serial signal passing through an adaptive linear equalizer into a parallel signal, and inputting the parallel signal as a feature vector into a DNN equalizer assisted by a kernel function; through K-DNN training, classifying the feature vectors into a category with the maximumprobability to obtain an original signal; The device adopts the nonlinear distortion compensation algorithm and structurally comprises a transmitting end and a receiving end, and the receiving end carries out offline processing on signals through a processing chip and comprises the steps of using a S-MCMMA's adaptive post-equalizer to compensate linear distortion; using K-DNN equalization and demapping for nonlinear distortion compensation to obtain the original signal.. The method can conveniently and efficiently compensate the nonlinear distortion of the signal caused by the complex channelenvironment in the existing underwater wireless optical communication, and has important practical significance.

The invention discloses an underwater wireless optical communication method and system, and the method comprises the steps: controlling a transmitting end to carry out the precoding of an original electric signal, and carrying out the phase modulation of light through an optical phase modulator, so as to generate an optical modulation signal; sending the light modulation signal to a receiving endthrough an underwater channel; and controlling the receiving end to perform self-coherent demodulation on the optical modulation signal so as to convert the optical modulation signal into an originaloptical signal, and converting the original optical signal into an original electric signal through the optical signal detector. According to the method, an electric signal can be converted into an optical modulation signal, the intensity of light is not changed, information is carried only through the phase of light, and different from the traditional mode of realizing modulation by changing thelight intensity, the signal is transmitted to a receiving end through an underwater channel; and when the receiving end performs demodulation processing by using the single-photon detector array, various interferences and losses of signals in the underwater transmission process can be eliminated, the signal-to-noise ratio is increased, and the transmission distance, the anti-interference capability and the stability of underwater wireless transmission are improved.

The invention provides a method for improving wireless optical communication performance under strong flowing water, which comprises the following steps of: respectively calculating flicker indexes and structural constants of a plane wave and a spherical wave under an aperture average effect under strong ocean turbulence; modulating an input signal of an underwater wireless optical communication system by adopting a DPSK modulation technology, and transmitting the modulated signal through a Gamma-Gamma distributed strong oceanic turbulence channel; receiving a signal by using an aperture receiving technology, and obtaining an average bit error rate analytical expression of the underwater wireless optical communication system under heterodyne differential phase shift keying modulation through a Whittaker function; and comparing and analyzing the average bit error rate under different influence factors through MATLAB software by utilizing the obtained average bit error rate analytical expression. The method has the advantages that the rule of improving the performance of the UWOC system is well disclosed, and the method can be used for designing the UWOC system with more excellent performance, namely improving the performance of the UWOC system.

The invention provides a low-cost infrared band underwater wireless optical communication device which is formed by a watertight casing, a light emitting and receiving lens and a photoelectric conversion module. The light emitting and receiving lens has a focusing lens and a fiber collimator inside, the optical fiber collimator is used to perform beam expansion when light is emitted, and the focusing lens is used to perform focusing when the light is received. The mutual conversion of an electrical signal and an optical signal can be achieved by the photoelectric conversion module which is formed by a standard infrared SFP optical module and a Gigabit photoelectric switch. The photoelectric conversion module is installed in the watertight casing, the standard infrared SFP optical module isflexibly connected to the optical transmitting and receiving lens through an optical fiber, and the Gigabit optical switch is connected to an external system through a Gigabit Ethernet interface. According to the low-cost infrared band underwater wireless optical communication device, the underwater close distance point-to-point high-speed wireless communication is achieved by using an infrared band spatial light signal, and the device has the advantages of small volume, low cost and high speed.

The embodiment of the invention provides an underwater wireless optical communication system. A transmitting end comprises an audio and video signal input module, a signal conditioning circuit and a light source array. and a receiving end comprises a photoelectric detection module, a demodulation module and an audio and video signal output module, wherein the light source array is an array formedby spatial distribution of a plurality of first light emitting diodes and a plurality of second light emitting diodes; the light-emitting frequency bands of the first light-emitting diode and the second light-emitting diode are different. The photoelectric detection module comprises a photomultiplier and four avalanche photodiodes, a multiple-input-multiple-output signal transmission mode is formed, multiple diversity communication modes such as space diversity, frequency diversity and time diversity can be achieved, underwater channel fading resistance and communication performance of the system are remarkably improved, and communication performance of the system is remarkably improved.

The invention provides a high-power underwater wireless optical communication transmitter. A watertight connector supplies power to a modulation circuit, an array driver and an LED device, meanwhile,the watertight connector is responsible for external communication, and after modulation of the modulation circuit, voltage provides drive for the LED device through the parallel array driver, so thatthe LED device emits light, light is transmitted through the optical antenna, and underwater wireless transmission is achieved. According to the invention, the shell and seawater are used for rapid heat dissipation; the focus is controlled at the LED lamp wick, the optical divergence angle is compressed, the light energy is gathered, the light beam expansion loss is reduced, the peak power is improved on the premise that the average power is not changed, longer-distance transmission is achieved, the transmitting light power can be further improved on the premise that the modulation rate is guaranteed, and longer-distance underwater wireless transmission is achieved.

The invention discloses an MOPA underwater wireless optical communication transmitting device based on Manchester coded signals. The device comprises a signal processor for generating Manchester codedsignals, wherein the signal processor is connected with an amplifier and an attenuator, the attenuator is connected with the bias driver, the bias driver drives a laser diode, optical signals generated by the laser diode are focused by a first convex lens and then coupled into an optical fiber isolator, the optical fiber isolator is connected with a pump beam combiner, the input end of the pump beam combiner is further connected with a pump laser, light emitted by the output end of the optical fiber isolator and pump light emitted by the pump laser are combined together through the pump beamcombiner and then enter a doped optical fiber, and the doped optical fiber is connected with a second convex lens, a third convex lens, a frequency doubling KTP crystal and a fourth convex lens. According to the invention, high power output can be realized, the complexity of a high-speed communication system is reduced, and the communication rate of signals is improved.

The invention relates to an underwater wireless optical intelligent rapid alignment system and an alignment method, which are suitable for intelligent rapid alignment between a receiving device and a transmitting device of an underwater wireless optical communication system, and can also be applied to rapid alignment between spatial optical transmitting and receiving devices in air to realize rapid and normal communication of the wireless optical communication system. According to the device, rapid alignment between a light emitting device and a light receiving device of the underwater wireless optical communication system can be realized, a communication link is established, and rapid and normal communication of the system is realized. Compared with a traditional manual alignment method, the method has the advantages that the alignment difficulty is reduced, the alignment time is saved, and the working efficiency is improved.

The invention provides an underwater wireless optical communication infield channel simulation device. The device comprises a box body, the box body is a accommodating cavity with an opening in the upper portion, a cover plate is connected to the opening in the upper portion of the box body, a front porthole, a water pump and a water pipe connector of the water pump are arranged on a front panel of the box body, a rear porthole is arranged on a rear panel, a movable partition plate is arranged between the front panel and the rear panel, and an illuminometer is arranged on one side panel. Tap water is injected into the simulation device, aluminum hydroxide, sea salt and the like are added into the water to simulate suspended particles and seawater salinity in the water, and underwater environments under different visibility are obtained; a movable partition plate mode is adopted, so that the problem that dynamic analogue simulation cannot be performed on channel environments with different distances due to the fact that the length of a traditional box cannot be changed is solved; different water flow rates are generated through pump compression, and then the influence of underwaterchannels on optical communication under different distances, different water flows, different communication rates and coding modes is developed, so that an underwater channel simulation model is constructed.

The invention discloses a method for calculating the bit error rate (BER) of an underwater wireless optical communication system based on parallel multi-hop architecture. The method comprises the following steps: establishing a transmission model suitable for a parallel multi-hop-underwater wireless optical communication system by adopting an optimal path selection scheme of a maximum and minimumcriterion based on LN ocean turbulence distribution under the consideration of the effect of path loss; deriving a system probability density function and a cumulative distribution function under thejoint action of LN turbulence and the path loss; obtaining a closed system BER expression with a Gauss Laguerre polynomial, and performing simulation verification by a Monte Carlo method; bringing different parameters into a closed average BER expression to obtain the influences of the parameters on system performance; and introducing LDPC coding to compare the influences of different structure parameters, bit rate and maximum iteration times and code length on the performance of the parallel multi-hop-UWOC system. The method effectively takes into account a plurality of factors affecting theperformance of the system, which conforms to the actual situation more.

The invention provides an underwater laser light source system and an underwater wireless optical communication system, the underwater laser light source system comprises a laser light source, and anaspheric lens and a beam expanding collimating lens group which are sequentially located on an emergent light path of the laser light source, and the laser light source is located at the focus of theaspheric lens; the laser source is used for emitting laser; the aspheric lens is used for collimating the laser along the fast axis direction and the slow axis direction so as to compress the divergence angle of the laser into a first preset range; the beam expanding collimating lens group comprises a plano-concave lens and a plano-convex lens which are sequentially located on an emergent light path of the laser light source, and the beam expanding collimating lens set is used for carrying out beam expanding collimation on the laser, so that the divergence angle of the laser emitted by the underwater laser light source system is small, and it can be guaranteed that the transmission distance of the laser in water is long enough and the power density is large enough.

The invention belongs to the field of underwater wireless optical communication, and relates to a dual-wavelength underwater wireless optical communication method and system. The method comprises the following steps: controlling an emission system to combine two beams of light with different wavelengths to form an optical signal A; converting the optical signal A into an optical signal B with a divergence angle theta, and sending the optical signal B to a receiving end through a channel; controlling a receiving system to divide the received optical signal B into two beams, so that one beam of optical signal is processed into an electric signal C1 through filtering and photoelectric conversion, the other beam of the optical signal is processed into an electric signal C2 through filtering, photoelectric conversion and smooth filtering; and subjecting the electric signal C1 and the electric signal C2 to light intensity compensation processing through a data processing module so as to output an electric signal out; and demodulating and decoding the electric signal out to finally obtain an original signal. Compared with the existing space diversity technology, the system uses the same optical receiving module to receive light intensity, is only composed of two photoelectric detection circuits, and is small in size, low in cost and more compact in overall structure.

The invention provides an underwater wireless optical communication receiver based on a depth condition generative adversarial network, and the scheme provides a new DNN detector which can deal with the SD problem in a UWOC scene with CSI change. In the scheme, a CGAN structure is provided for generating a signal with a DNN detector training characteristic to assist in realizing an SD process. The achievable system performance of most existing DNN designs only depends on an offline training process, and the difference is that a CSI change tracking function provided by the CGAN structure provided by the invention can be combined with a network after offline training, online signal generation is realized, and thus better SD performance is provided.

The invention relates to an underwater wireless optical communication receiving method and device based on gain control in a detector. The method comprises the following steps: S1, converting a received communication optical signal into a communication current signal by using a photomultiplier; S2, converting the communication current signal into a communication voltage signal; S3, generating a DC voltage according to the communication voltage signal, and controlling the internal gain change of the photomultiplier by using the DC voltage so as to control the amplitude change of the communication voltage signal, thereby enlarging the receiving optical power range of the receiving device, wherein the communication voltage signal is used as an electric signal subsequently processed by the receiving device. According to the method, detection of different optical power signals is achieved through the method of controlling the internal gain of the photomultiplier through the direct-current voltage, the receiving optical power range of the receiving device is enlarged, and rapid response can be achieved for the signals with different optical powers.

The invention discloses a underwater portable wireless optical communication equipment and system, relates to the field of underwater wireless optical communication, and aims to solve the problems that an underwater wireless optical communication channel is extremely unstable and underwater information is difficult to continuously and efficiently transmit due to the fact that existing underwater wireless optical communication equipment cannot be stably aligned with overwater wireless optical communication equipment. According to the scheme, the equipment comprises a wearable device and a suspension device, the suspension device is connected with the wearable device in a wired or wireless mode, blue, green and red light emitted by the suspension device is received by a receiving device of overwater communication equipment, and wireless optical communication between the underwater wireless optical communication equipment and the overwater communication equipment is achieved. The suspension device is not affected by irregular motion of a frogman, and optical communication alignment and stability between the suspension device and the overwater communication equipment are better guaranteed. the wireless optical communication system can control the transmitting module to adjust the angle and the direction in real time, so that the transmitting module is aligned with the receiving device of the overwater optical communication equipment at any time, the stability of an optical communication channel is ensured, and the transmission efficiency of optical communication is improved.

In the invention, according to Frantz-Nodvik-equations, after parameters such as the order of pulse position modulation (PPM), the width of pulses and the like are determined, different pulse interval time generated by the PPM is calculated, intensity tables are generated at different pulse intervals, and data is stored; in actual use, after information is modulated in a PPM mode, corresponding electric signals are generated according to the generated intensity tables, and the electric signals are output; after being amplified by a power amplifier, the electric signals directly drive a seed source of an MOPA system to generate seed light with signal modulation; and the seed light is amplified through a multi-stage ytterbium-doped fibre-optic amplifier, and generated high-power fundamental frequency light becomes green laser capable of being used for underwater wireless optical communication after being subjected to frequency doubling.

The invention belongs to the technical field of underwater wireless optical communication, and discloses a collimation optical path design method for increasing the working distance of an underwater wireless optical communication system, which is suitable for a system of which a light transmitting end and a light detecting end both adopt an array form. Theoretical analysis is firstly carried out on a collimation light path, then light path simulation is carried out in software, and finally verification is carried out in an optical communication system. Results show that the designed optical lens group has good collimation and collection effects on optical signals transmitted in the system, solves the problem of non-uniform illumination of light spots on a detection surface caused by mutual conjugation of light emission and light detection ends in a traditional optical path collimation method, and effectively improves the utilization rate of optical power. And the working distance of the system is prolonged.