37 results about "Underwater wireless optical communications" patented technology

The application discloses an underwater wireless optical communication device based on a single photon detector, which comprises a first single photon communication device and a second single photon communication device for bidirectional communication, and each of the first single photon communication device and the second single photon communication device comprises a laser emission unit, a signal receiving unit, a signal comprehensive processing unit and a power module; the laser emission unit loads a received modulated electric signal into an optical signal and outputs the optical signal, and simultaneously emits auxiliary alignment laser for communication device alignment; the signal receiving unit converts the received optical signal into an electric signal through a single photon detector and transmits the electric signal to the outside, and simultaneously, the signal receiving unit receives auxiliary alignment laser to complete communication device alignment; the signal comprehensive processing unit converts communication information of a host computer into a modulated electric signal after receiving the communication information, transmits the modulated electric signal to the laser emission unit, demodulates and restores the electric signal transmitted by the signal receiving unit into communication information, and then transmits the communication information to the host computer. The application can improve underwater communication distance and meet the requirements of long-distance wireless optical communication in different water quality environments.

The application discloses a relay and power joint distribution method based on underwater wireless optical communication and belongs to the technical field of wireless optical communication. The system average error rate performance expression derived is used as a target function, and the Hungarian algorithm is used to distribute relay nodes for source nodes; based on the obtained source node and relay node pairing combination, the particle swarm algorithm is used to optimize the power distribution of the source node and the relay node under the constraint condition of total power, with the minimum system average error rate as the target; based on the updated power distribution result of the source node and the relay node, the system average error rate is calculated; if the absolute value of the difference between the new system average error rate and the original system average error rate is greater than a set threshold value, the Hungarian algorithm is used again to distribute relay nodes for source nodes, and the particle swarm algorithm is used to optimize the power distribution, until the absolute value of the difference between the current system average error rate and the last system average error rate is less than the set threshold value. The relay and power joint distribution method based on underwater wireless optical communication provided by the application avoids the defects of large operation amount and high complexity of the exhaustive search method, better realizes the relay distribution and power distribution problems in the weak ocean turbulence environment with lower complexity, and improves the performance of the multi-user multi-relay underwater wireless optical communication system.

The invention relates to a spread spectrum and time-digital conversion cooperative underwater communication measurement system and method, belongs to the technical field of underwater wireless optical communication, and solves the technical problems of limited communication rate and insufficient positioning precision in an underwater complex environment. The measurement system comprises a master-end underwater wireless optical communication machine and a slave-end underwater wireless optical communication machine, each of the master-end underwater wireless optical communication machine and the slave-end underwater wireless optical communication machine comprises an optical transmitting unit, an optical receiving unit, a signal processing unit, an upper computer and a shell. And the optical transmitting unit, the optical receiving unit and the upper computer are respectively connected with the signal processing unit. The optical transmitting unit, the optical receiving unit and the signal processing unit are arranged in the shell, and the upper computer is arranged outside the shell. The measurement method comprises the steps of system initialization and link establishment, communication and time service synchronization, distance measurement signal triggering and transmitting, and distance calculation and display. The method is used for underwater robot collaborative operation, ocean monitoring and deep sea detection.

The invention belongs to the technical field of underwater wireless optical communication, and particularly relates to an underwater wireless optical communication base station and a communication coverage method. The base station is deployed on the seabed, a binocular camera is used for collecting images of positioning markers on the underwater robot in real time, and the three-dimensional relative position of the underwater robot relative to the base station is calculated based on underwater calibration parameters. And then, the communication coverage method generates and encodes position correction information according to a preset optimal communication area threshold value, and sends the position correction information to the underwater robot through an optical communication link. By fixing the position of the base station, simplifying the alignment dimension and combining high-precision visual guidance, the communication coverage range is remarkably expanded, the complex three-dimensional alignment problem is simplified into a two-dimensional plane alignment task, and the stability and reliability of an underwater wireless optical communication link are greatly improved.

The application belongs to the technical field of underwater wireless optical communication and relates to an underwater wireless optical communication device awakened by an acoustic signal and a standby awakening communication method. The device comprises a cabin top light transmission cover, an internal light transceiving array, an acoustic communication transceiving module, a main control unit and a power module. In a standby state, the main control unit controls the power module to cut off the power supply of the internal light transceiving array and only maintains the acoustic communication transceiving module to perform low-power acoustic monitoring; when a preset acoustic awakening signal is received, the acoustic communication transceiving module triggers the main control unit to wake up and completes bidirectional handshaking through acoustic verification messages. After verification succeeds, the main control unit connects the power supply of the internal light transceiving array, establishes a high-speed optical communication link and exchanges data. The scheme can reduce the standby power consumption of an underwater communication node, reduce false awakening and improve long-term deployment capability.

The present application relates to underwater cluster vehicle positioning system and method, specifically relates to a kind of underwater cluster vehicle cooperative positioning system and method based on wireless optical communication, solve the technical problems that existing underwater cluster vehicle is difficult to guarantee the consistency and cooperation between nodes.The underwater cluster vehicle cooperative positioning system based on wireless optical communication provided by the present application is based on underwater wireless optical communication technology, communication rate is high, delay is low, transmission capacity is large, and the time reference unit of main node positioning device is used to synchronize and tame the crystal oscillator in clock synchronization and tame unit in slave node positioning device, to realize the cooperative time service of multiple slave node underwater vehicles, and further ensure positioning accuracy;At the same time, the autonomous navigation unit of underwater vehicle itself can be used, and only one main node underwater vehicle equipped with high-precision main node autonomous navigation unit and time reference unit can realize the cooperative positioning of underwater cluster vehicle.

This invention provides an energy adaptive adjustment device and method for underwater wireless optical communication, relating to the field of underwater wireless optical communication. The device includes: an adaptive adjustment module, a signal processing module, an optical antenna, a tunable optical attenuator, and a beam splitter. The tunable optical attenuator adjusts the light intensity energy of the optical signal according to the feedback signal from the adaptive adjustment module. The beam splitter splits the optical signal output from the tunable optical attenuator into two paths, one transmitted to the adaptive adjustment module and the other to the signal processing module. The signal processing module generates an energy calibration result and sends it to the adaptive adjustment module, and receives the optical signal from the beam splitter, processes it, and outputs it. The adaptive adjustment module receives the signals from the beam splitter and the signal processing module, processes them, and feeds them back to the tunable optical attenuator. This invention solves the problem that the signal energy detected by the receiving end of the device cannot be adaptively adjusted, improving the practicality and robustness of the communication device.

The invention discloses an underwater wireless optical communication transmitter based on a blue-green light phased array, and the transmitter comprises a narrow-linewidth seed laser source which is used for generating narrow-linewidth laser; the beam splitting device is used for splitting the narrow linewidth laser into a plurality of sub light beams; a blue-green laser diode array, each blue-green laser diode receives a path of sub-beam through an optical injection locking technology and outputs high-power narrow-linewidth blue-green laser, and the blue-green laser diode is based on a gallium nitride multi-quantum well structure; the phase control array corresponds to each blue-green laser diode and is used for adjusting the phase of each path of high-power narrow-linewidth blue-green laser; and the large-aperture transmitting antenna array is connected with the phase control array and is used for carrying out collimation processing on the laser beam after phase modulation and transmitting the laser beam to an underwater environment to form a large-aperture optical phased array. The device can significantly improve the power of emitted light beams, greatly improves the quality of the light beams, and improves the communication distance.

The application provides a high-speed light-emitting diode underwater wireless optical communication system and method, and belongs to the technical field of underwater optical communication; a transmitting end comprises successively connected adaptive coding module, 16QAM mapping module, OFDM modulation module, digital-analog conversion module and LED array light source module; a receiving end comprises successively connected photoelectric detection module, signal processing module of integrated post-equalization circuit, analog-digital conversion module, digital filter module, OFDM demodulation module, phase estimation module, 16QAM demapping module and Viterbi decoding module; the application provides a high-speed LED underwater wireless optical communication system and method based on 16-order quadrature amplitude modulation-quadrature frequency division multiplexing and hardware equalization, adopts hardware equalization to effectively expand the modulation bandwidth of the LED light source, significantly improves the transmission performance of high-frequency signals, and sufficiently utilizes the frequency spectrum resources through high-order modulation, and significantly improves the data transmission rate of the system.

The application relates to underwater optical communication technology and discloses a kind of underwater wireless optical communication systems based on rotary laser transmitter, to solve the problem that transmission accuracy of existing underwater wireless laser communication technology is easily affected by transmission medium turbidity and transmission distance.The rotary laser transmitter device of the system is connected with a laser transmitter by each laser controller, and a plurality of laser transmitters are uniformly arranged on the rotary support in the circumferential direction, the device is provided with a transmission hole, and the rotary support is driven by a motor to rotate; the laser receiver receives optical signals from the rotary laser transmitter device, converts the optical signals into electrical signals, and sends the electrical signals to a data acquisition card; the data processing module processes data sent by the data acquisition card; and the control module controls the operation of the laser controller and the motor according to the processing result.The application can adaptively adjust the position and working condition of each wavelength laser transmitter of the transmitting end according to water turbidity and transmission distance, and ensure the transmission accuracy of the system.

This invention relates to a large field-of-view diversity receiver for underwater wireless optical communication, belonging to the field of underwater optical communication technology. It includes a top lens-detector module pointing vertically towards the zenith and four surrounding side lens-detector modules. The four side modules are evenly distributed along the circumference and have a uniform tilt angle relative to the zenith direction, causing the spatial fields of view of each module to partially overlap, thus synthesizing a large composite field of view. Each module consists of a defocused condenser lens and a photodetector. This invention avoids the trade-off between gain and field of view limitation of traditional single-lens receivers, relaxing communication alignment requirements while retaining the high-speed transmission advantage of small-area detectors. Combined with a signal combining algorithm, it can effectively combat underwater signal fading, making it suitable for underwater wireless optical communication systems.

The invention provides an underwater wireless optical communication adaptive transceiving system, which comprises a signal transmitter and a signal receiver, and is characterized in that the signal transmitter comprises a plurality of direct modulation semiconductor lasers and a modulation unit capable of converting digital signals into analog signals for modulation of the semiconductor lasers. The signal receiver comprises a spectroscope, an optical power meter probe and a signal receiver; the signal receiver captures optical signals through the digital signal processing module by using the plurality of optical detectors and converts the optical signals into electric signals, and the electric signals pass through the analog-to-digital converter and are output to the FPGA board card in the form of digital signals. According to the invention, service transmission can be carried out in real time, so that the problem of bandwidth limitation easily occurring when a single channel transmits a high-rate signal is solved, and the overall transmission rate or anti-interference capability of the system is further improved.

The application relates to the field of underwater wireless optical communication and discloses an underwater wireless optical communication system based on index modulation technology and a multi-band CAP technology, which comprises an optical transmitting module, an optical receiving module, a transmitting end signal processing module and a receiving end signal processing module. The transmitting end signal processing module carries out sub-band multi-mode ordering mapping and multi-band CAP modulation on original data, the receiving end signal processing module carries out multi-band CAP demodulation, multi-channel DFE equalization and signal-to-noise ratio weight-assisted multi-mode demapping on digital signals, and the original data is recovered. Compared with a traditional method, the mapping relationship between data and the ordering mode of a multi-constellation pattern is established, more index bit information can be transmitted, the error code rate can be reduced through the multi-channel DFE equalization and the weight-assisted demapping scheme, and the system performance is improved.

The invention provides a high-speed light-emitting diode underwater wireless optical communication system and method, and belongs to the technical field of underwater optical communication. The transmitting end comprises an adaptive coding module, a 16QAM mapping module, an OFDM modulation module, a digital-to-analog conversion module and an LED array light source module which are connected in sequence; the receiving end comprises a photoelectric detection module, a signal processing module of an integrated equalization circuit, an analog-to-digital conversion module, a digital filtering module, an OFDM demodulation module, a phase estimation module, a 16QAM demapping module and a Viterbi decoding module which are connected in sequence; according to the 16-order orthogonal amplitude modulation-orthogonal frequency division multiplexing and hardware equalization-based high-speed LED underwater wireless optical communication system and method provided by the invention, the modulation bandwidth of an LED light source is effectively expanded by adopting hardware equalization, the transmission performance of high-frequency signals is remarkably improved, spectrum resources are fully utilized through high-order modulation, and the optical communication efficiency is improved. And the data transmission rate of the system is obviously improved.

The invention discloses an underwater wireless optical communication physical layer security coding and decoding system and method based on a Polar code, and belongs to the technical field of underwater optical communication, and the system comprises a transmitting end, an underwater channel, a legal receiving end and an illegal eavesdropping end; the transmitting end carries out Polar code coding and modulation on original data and converts the original data into optical signals to be transmitted, and meanwhile, a backscattering detection module of the transmitting end evaluates signal conditions possibly detected by an illegal eavesdropping end; after being attenuated to a single photon level through an underwater channel, an optical signal is detected and decoded by a legal receiving end and an illegal eavesdropping end respectively; according to the underwater wireless optical communication physical layer safety coding and decoding system and method based on the Polar code, the reliability and safety of communication are achieved while coding and decoding are conducted on the Polar code, and information safety guarantee is provided for underwater wireless optical communication.

The application discloses a wireless optical communication method based on cooperative non-orthogonal multiple access and multi-user diversity, and mainly solves the problems of few accessible users and low user resource utilization in the prior art. The implementation scheme is as follows: a cooperative non-orthogonal multiple access underwater multi-user diversity wireless optical communication system is constructed; a source node selects far users and near users with the best channel according to a multi-user scheduling algorithm; the source node superimposes far user signals and near user signals in a power domain, and simultaneously sends the superimposed signals to the far users and the near users; the near users demodulate their own signals through serial interference cancellation; the near users send signals to the far users as relays by using a decode-and-forward protocol or an amplify-and-forward protocol; and the far users demodulate their own signals by selecting and combining two signals sent by the source node and the relay node. The application improves the number of user access, the source node can serve multiple user groups at the same time, and the system interruption performance is improved, and the application can be used in a multi-user underwater wireless optical communication system.

The invention discloses an efficient underwater optical detector based on a wavelength shift optical fiber. The photoelectric conversion efficiency and the detection sensitivity of an underwater optical detection system are improved. The specific implementation method comprises the following steps: 1, mounting a reflector behind the WSF array to improve the absorption and conversion proportion of the detector to incident blue light; 2, a reflector is installed at the tail end of the WSF array to guide excitation green light which is propagated in the back direction to a photoelectric detector to improve the signal intensity; and thirdly, the output of the WSF array is combined into one optical fiber by the optical fiber combiner, and exciting light is converged to a working area of the photoelectric detector. The method is not only suitable for underwater wireless optical communication, but also provides important technical support for various scientific researches related to the underwater environment, including marine biology and marine physics.

The invention relates to the technical field of underwater comprehensive docking systems, and discloses an underwater docking system integrating navigation, wireless communication and wireless power supply, which comprises a connection end and an execution end, the connection end and the execution end are in two-way communication based on a long-distance light guiding and low-speed data link, an electric energy, communication and guiding control module, a wireless electric energy transmission module and a short-distance high-speed data link, and the execution end enters optical guiding through sound guiding. The connection end and the execution end switch low-speed or laser high-speed communication and start energy complementation according to the distance, light vision guidance is modulated, so that the system has an underwater wireless optical communication function, and meanwhile, the underwater attenuation of light is lower than that of radio. Therefore, low-speed data transmission is achieved while guiding is conducted through the execution end in the recycling process, and under detection and switching of the guiding control module and the wireless electric energy transmission module, high-speed communication and wireless energy supplementation are started after the execution end reaches the connection end.

A synchronization method for a photon counting type underwater wireless optical OOK communication system, including the design of a transmission data structure and a synchronization method. The design of the data structure includes the design of the sending frame structure and the division of the received signal. The data is transmitted in the form of continuous frames, and the synchronization sequence is periodically embedded in the transmitted data. Before synchronization, the received signal is divided into slices of the same length; during synchronization, based on a frame-long received signal, the maximum likelihood joint estimation method is used to establish the corresponding optimization problem to find the synchronization sequence position, and some simplification is used to reduce the complexity of solving the original optimization problem. The present application solves the problem of poor transmission performance of the underwater wireless optical OOK communication system from the perspective of signal synchronization. The synchronization method is simple in form, and the complexity of the method is reduced by simplification, which is more suitable for the photon counting type underwater wireless optical OOK communication system. The present application can improve the synchronization performance with low complexity and improve the reliability of the photon counting type underwater wireless optical OOK communication system.

The invention discloses an underwater wireless optical communication signal detection method based on a multi-type detector array, and belongs to the technical field of underwater wireless optical communication and signal detection. The method comprises the following steps that: a receiving end receives optical signals by adopting a multi-type detector array comprising high-gain and low-gain photoelectric detectors, and converts the optical signals into M paths of electric signals; after up-sampling is carried out on each path of signals, weighted combination is carried out on M paths of signals by traversing weighting factors; calculating a projection vector, a judgment threshold and a pilot frequency bit error rate for each group of weighting factors, and solving an optimal weighting factor and a corresponding optimal projection vector by taking the minimum bit error rate as a criterion; and projecting the data symbol sampling point vector by using the optimal projection vector, and recovering 0 and 1 symbols in combination with the optimal judgment threshold. According to the invention, the detection advantages of multiple types of detectors are fused, the underwater large dynamic light intensity change can be adaptively coped, and the signal detection performance and the system reliability are significantly improved.

The invention discloses an underwater wireless optical communication base station device and system for simultaneous access of multiple users. The base station device comprises a multi-surface structural body, a plurality of optical transmitting terminals, a plurality of optical receiving terminals and a core control module, the polyhedral structural body adopts a spherical convex polyhedron topological form and is a regular polyhedron or a semi-regular polyhedron; the plurality of light emitting terminals are arranged on each end surface of the multi-surface structural body; the plurality of light receiving terminals are arranged at the center of each end surface and each vertex of the multi-surface structure body; the light emitting terminals are uniformly distributed at the periphery of the light receiving terminal at the center of the end surface; the core control module is used for controlling signal transceiving and processing and is electrically connected with the light emitting terminal and the light receiving terminal. The base station device and the system can realize 360-degree omnidirectional optical information transceiving without tracking and aiming, and support real-time omnidirectional access of a plurality of wireless optical terminal users, thereby providing reliable technical support for real-time efficient networking between underwater mobile platforms.

The application provides a kind of underwater wireless optical communication system error rate calculation method based on carrierless amplitude phase modulation, comprising: based on the underwater turbulent channel of lognormal distribution and considering the influence of absorption, scattering effect, establish the underwater wireless optical communication system model using carrierless amplitude phase modulation;Using Gauss-Hermite orthogonal integral formula, the closed expression of system error rate is obtained, and compared with the Monte Carlo simulation result, prove the correctness and effectiveness of expression;The related parameters of different underwater scenes are brought into the closed average error rate expression, and the influence of these parameters on system performance is evaluated.The underwater wireless optical communication system model established by the application comprehensively considers the influence of absorption, scattering and turbulence on performance, and is closer to the real marine environment;The error rate calculation method disclosed by the application can provide theoretical guidance for studying the performance of underwater wireless optical communication system in different scenarios.

The invention belongs to the technical field of underwater wireless optical communication (UWOC) and underwater robot control, and aims at solving the problems that an existing underwater optical communication system is high in alignment dependence and poor in communication link stability in a high-dynamic environment. The invention discloses a wireless optical communication module suitable for an underwater robot and an autonomous hovering control method for the underwater robot. The communication module can be integrated in an underwater robot frame and sealed cabins (1-1 and 1-13), and the hardware design of the communication module comprises a high-precision and low-distortion visible light modulation transmitting circuit (Figure 5), the circuit is powered by 3A constant current with low power ripple (Figure 4) and is combined with current feedback to ensure that the light intensity of a transmitting end LED (3-4) is controllable and the modulated signal is low in distortion; and the core of the visible light receiving circuit is that a trans-impedance amplifier (6-5) of the receiving circuit adopts an independent power supply to filter and supply power (figure 7), so that electromagnetic interference generated by digital equipment in a cabin is isolated, and the signal-to-noise ratio and the receiving reliability of analog signals are greatly improved. According to the autonomous hovering control method provided by the invention, a dual feedback mechanism is constructed by fusing an external accurate relative distance D (provided by stereoscopic vision guidance of a base station) and an internal real-time communication bandwidth B (measured in real time by tools such as Iperf and the like). According to the method, the problem that excessive correction or drifting is easily generated under underwater turbidity and water flow disturbance by only depending on navigation data or instantaneous visual data is solved. When the communication bandwidth B is reduced, the system firstly uses the distance D to carry out rapid correction; and when the connection is completely interrupted, entering a text {PROBING} exploration mode. According to the method, intelligent sensing and high-robustness autonomous position keeping of the underwater robot on a communication link are realized, and an efficient and high-bandwidth stable optical communication link can be continuously maintained in a complex underwater environment.

The invention discloses an underwater optical network routing optimization method based on distance perception and motion prediction, relates to the technical field of underwater wireless optical communication networks, and aims to solve the problems in the prior art. The method realizes intelligent routing optimization through signal attenuation distance perception, multi-sensor trajectory prediction and opportunistic routing decision. Over-water and under-water nodes establish optical communication links through LED emitters and photoelectric detectors, and track sensing is achieved by configuring various motion sensors. Comprising six core steps of physical connection establishment, signal attenuation distance perception, multi-sensor fusion trajectory prediction, hierarchical network state convergence, multi-target optimization opportunity routing decision and adaptive parameter optimization. Physical layer distance sensing and prediction driving routing are innovatively combined, the key technical problems that a traditional underwater optical communication routing algorithm cannot adapt to node dynamic drift, lacks accurate distance sensing and cannot predict network evolution are solved, and the communication performance and energy consumption efficiency of the dynamic underwater optical network are remarkably improved.

The invention discloses an underwater wireless optical communication system based on adaptive emission and lightweight reception, and relates to the field of underwater wireless optical communication, comprising an adaptive emission module which adaptively selects a signal processing path according to an underwater channel condition and performs electro-optical conversion; the lightweight receiving module receives weak optical signals transmitted underwater and converts the weak optical signals into digital signals; the power supply control module outputs a stable current source; the FPGA module carries out modulation and demodulation and filtering pre-equalization on the signal; the system adopts a modular layered architecture, takes blue and green light bands as communication carriers, realizes full duplex underwater wireless optical communication, fundamentally meets the core requirements of an underwater combat environment on communication concealment and high data transmission rate, remarkably reduces the power consumption of the system, and realizes a short-distance and low-power-consumption communication link.

This disclosure relates to a capture, tracking, and aiming system and method for underwater optical communication. The system includes a first communication terminal and a second communication terminal, both equipped with capture, tracking, and aiming devices. Each capture, tracking, and aiming device includes a control chip, a transmitting module, and a receiving module. The control chip is connected to both the transmitting and receiving modules. The transmitting module includes a laser and a piezoelectric ceramic deflector, both connected to the control chip. The piezoelectric ceramic deflector is used to adjust the direction of the laser beam emitted by the laser. The receiving module includes a single-photon detector and a beam reducer, with a filter positioned between the single-photon detector and the beam reducer. The single-photon detector is connected to the control chip. This system enables rapid automatic alignment between the two ends of an underwater wireless optical communication system based on photon counting, thereby achieving automatic beam alignment between underwater devices and enabling bidirectional high-speed single-photon-level optical communication.

The invention relates to an underwater cluster vehicle positioning system and method, in particular to an underwater cluster vehicle cooperative positioning system and method based on wireless optical communication, and solves the technical problem that consistency and collaboration among nodes of an existing underwater cluster vehicle are difficult to guarantee. The wireless optical communication-based underwater cluster aircraft cooperative positioning system provided by the invention is based on an underwater wireless optical communication technology, is high in communication rate, low in time delay and large in transmission capacity, and utilizes the time reference unit of the main node positioning device to realize cooperative positioning of underwater cluster aircrafts. Time synchronization and taming are carried out on a crystal oscillator in a clock synchronization and taming unit in the slave node positioning device, so that cooperative time service of a plurality of slave node underwater vehicles is realized, and the positioning precision is further ensured; meanwhile, the autonomous navigation unit of the underwater vehicle can be utilized, and only one main node underwater vehicle equipped with a high-precision main node autonomous navigation unit and a time reference unit is needed, so that the cooperative positioning of the underwater cluster vehicle can be realized.

The invention discloses an asynchronous code division multiple access underwater wireless optical communication system multi-user access method based on optical wireless access point direction self-adaption, and belongs to the technical field of wireless optical communication. According to the method, user azimuth angle estimation and communication are synchronously realized at an OAP end by utilizing a detector array, and a receiving end direction self-adaptive mechanism is implemented based on multi-user detection and arrival angle information so as to maximize the system capacity. And a multi-user access control strategy is formed by further combining a dynamic code word distribution protocol. According to the method, the difficulty in underwater clock synchronization is overcome, the throughput, the number of users and the fairness are improved by optimizing the OAP space orientation, and an effective solution is provided for practical application of UOWC multi-user communication.

The invention relates to the technical field of underwater wireless communication, in particular to an underwater wireless optical communication system based on a vertical external cavity surface emitting semiconductor laser, and the system comprises a blue light source which is used for generating a blue light beam; the waveform generator is used for generating a simulation model; the collimating and beam expanding device comprises a long-focal-length lens and a longer-focal-length lens which are respectively used for focusing the blue light beam to obtain a primary focused light beam and focusing the modulated light beam penetrating through the water body to obtain a secondary focused light beam; the acousto-optic modulator is used for modulating the primary focusing light beam by using an analog signal to obtain a modulated light beam; the signal receiver is used for receiving the secondary focusing light beam; and the signal recording and analyzing device is used for recording and analyzing the signals received by the signal receiver. Compared with an underwater wireless optical communication system based on continuous light, the underwater wireless optical communication system based on continuous light has lower output optical power attenuation and bit error rate, and has better communication quality during high scattering concentration and high-rate data transmission.

The invention discloses a time division multiplexing-Manchester encoding high-speed modulation and demodulation method and device for underwater wireless optical communication. The device comprises a transmitting end and a receiving end. In a modulation module of a transmitting end, on the basis of Manchester encoding, according to system and channel characteristics, a PPM-form signal is used as a main frame header, a Manchester encoding-form signal is used as an auxiliary frame header, and the PPM-form signal and the Manchester encoding-form signal are combined with an information signal after Manchester encoding and then are transmitted out through time division multiplexing. A signal processing module of a receiving end preprocesses a received signal by adopting smooth mean filtering, then performs multi-channel threshold-free parallel demodulation larger than the period number of a main frame header, realizes signal frame synchronization by utilizing the main frame header signal after the main frame header signal is identified, realizes signal bit synchronization by utilizing a Manchester encoding sub-frame header, and finally demodulates an information signal. According to the invention, the signal discrimination and stability of the transmitting end and the signal identification and anti-interference capabilities of the receiving end are enhanced, and the method is of great significance to an underwater low-bandwidth optical communication system.