Soochow University

Xiaodi You

Gangxiang Shen

Zile Jiang

Mingyi Gao

Chaoran Xiong

Lei Wang

Pengfei Wang

Fengchu Cao

Xiaobo Yang

The invention relates to a multi-source wireless optical communication spectrum sensing system, including: a transmit end, configured to transmit an optical signal, the transmit end including multiple LEDs; and a secondary user terminal, configured to: receive the optical signal transmitted by the transmit end, convert the optical signal into an electrical signal, filter out a direct current component in the electrical signal to obtain a filtered electrical signal, sample the electrical signal to obtain sampling data and a corresponding sampling quantity, perform channel estimation based on the sampling quantity and acquired location data of the secondary user terminal to obtain a channel matrix, calculate a detection metric M and a decision threshold K based on the channel matrix, the sampling data, and the sampling quantity, and determine, based on a value relationship between M and K, whether a channel is occupied by a primary user.

Multi-source wireless optical communication spectrum sensing system and method

The present invention provides a 3D wireless optical positioning method and system, including the steps of: arranging two LED lamps on the ceiling to transmit optical information and provide illumination; arranging a receiver including two photodetectors in a receiving plane; calculating the distance between the LED lamps and the photodetectors respectively through the TOA (Time of Arrival) method; and finally determining the actual position and orientation angle of the receiver based on the geometrical relationship between the LED lamps and the photodetectors in the XYZ coordinate system, the two photodetectors having a distance determined as l therebetween and being situated in the same receiving plane, the receiver being situated below the two LED lamps, the range where the receiver is to be positioned being on any side of the plane consisting of the two LED lamps and the origin.

3D wireless optical positioning method and system

Probabilistic shaping quadrature amplitude modulation (QAM) based on Maxwell-Boltzmann distribution is particularly important in coherent optical communication, which can approach the Shannon limit more desirably in the case of a finite signal-to-noise ratio. However, standard coherent optical digital signal processing algorithms are not optimal for demodulation of PS higher-order QAM signals. The invention provides a probabilistic shaping QAM dynamic equalization method that intercepts multiple inner rings after clock recovery and updates the convergence radius and area of a conventional blind dynamic channel equalization algorithm using a peak density K-means clustering algorithm. The clustering algorithm gives centroid labels and a quantity of classifications required for K-means, which does not require a large number of iterations of K-means, thereby reducing the complexity and improving the accuracy. The updated decision area and decision radius reduce errors in the dynamic equalization algorithm, thereby improving the accuracy of probabilistic shaping QAM digital signal processing.

Probabilistic shaping QAM dynamic equalization and digital signal processing method

The present invention provides a wireless optical communication data transmission apparatus and method, including a transmit module and a receive module, where the transmit module includes a transmission gate, and the transmit module is configured to convert serial data into multipath control signals to control the transmission gate to output an electrical signal, convert the electrical signal into an optical signal, and transmit the optical signal to the receive module; and the receive module includes a peak value detector and a comparator group, and the receive module is configured to convert the received optical signal into the electrical signal and output the serial data after threshold determination by the comparator group, where the peak value detector provides a reference voltage to the comparator group according to the received electrical signal, and the comparator group performs voltage division according to the reference voltage to determine a threshold.

Wireless optical communication data transmission apparatus and method

The invention provides a visible light communication system with adaptive dimming and a modulation and demodulation method. The system includes: a source; an adaptive M-PAM modulator, separately modulating a signal transmitted by the signal source into a first and a second electrical signal; and a dual-path pulse generator, alternately generating a first and a second pulse control signal, where the first and the second pulse control signal are both periodic signals, where when a remaining operating duration of a high level of the first pulse control signal equals to a time of a rising edge of the second pulse control signal, the second pulse control signal starts to be generated, and when a remaining operating duration of a high level of the second pulse control signal is equal to a time of a rising edge of the first pulse control signal, the first pulse control signal starts to be generated.

Visible light communication system with adaptive dimming and modulation and demodulation method

The present invention discloses a capacity optimization method for a mobile optical wireless communication system and a communication method and system. The capacity optimization method includes the following steps: establishing a mobile channel impulse response model; calculating an electrical signal-to-noise ratio (SNR) of an output of a receiver; calculating bit error rate (BER) values of an optical wireless communication system in different candidate modulation formats according to the electrical SNR of the output of the receiver; selecting a first modulation format and a second modulation format from the different candidate modulation formats; determining quantities of chips in the first modulation format and the second modulation format in each data frame; and building a time domain hybrid modulation frame according to the quantities of chips in the first modulation format and the second modulation format, modulating data by using the time domain hybrid modulation frame, and performing data transmission.

Capacity optimization method for mobile optical wireless communication system and communication method and system

The invention provides a method for nonlinear compensation of coherent high-capacity high-order QAM system, including: deploying an OPC on an intermediate link of communication between a transmitter and receiver, and performing phase conjugation on a transmitted signal based on the OPC to generate idler; performing phase recovery on a compensated signal at the receiver to obtain a constellation diagram, simulating a nonlinear function relationship between a transmitted signal and a received signal by using a trained and learned CVDNN, and performing nonlinear compensation on the constellation diagram to obtain the compensated constellation diagram; and calculating a Q-factor based on the compensated constellation diagram, and evaluating communication performance by the Q-factor. Nonlinear compensation is performed on a transmitted signal by using an OPC+CVDNN method to equalize nonlinear degradation of an optical fiber in a WDM coherent optical communication system.

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Suzhou, China

Xiaodi You