12 results about "Qam modulation" patented technology

This invention relates to the field of unmanned aerial vehicle (UAV) communication technology, and in particular to a communication method for a dual-channel UAV line-of-sight (LAS) communication system. The method includes: acquiring communication quality, acquiring the optimal transmission frequency, acquiring the UAV's mission priority, transmitting video stream data, and performing multipath fading compensation steps. The method sets up high-frequency and low-frequency channels, calculates frequency quality indicators using signal-to-noise ratio (SNR), signal rate, and bit error rate (BER), and dynamically selects the optimal transmission frequency. Communication resources are allocated based on mission priority to ensure priority transmission of critical commands. Innovatively, differential geometry theory is used for multipath fading compensation, mapping the communication signal to a Riemannian manifold space, extracting fading features, and optimizing the processing. High- and low-frequency channel collaborative compensation is achieved, with mutual enhancement through received spectrum analysis and training sequence correction. Adaptive QAM modulation is supported, dynamically adjusting modulation parameters according to manifold curvature to construct a star-shaped multi-node communication network.

The application discloses a kind of adaptive QAM and OFDM bimodulus intracorporeal ultrasonic communication system and method based on channel estimation, belong to intracorporeal ultrasonic communication technical field, the transmitting end is configured with single carrier QAM modulation mode and multicarrier OFDM modulation mode, real-time evaluation intracorporeal ultrasonic channel quality in receiving end, according to the optimal modulation mode of evaluation result, according to the optimal modulation mode generation mode switching instruction, the mode switching instruction is sent to transmitting end, transmitting end according to the mode switching instruction seamlessly switches between single carrier QAM modulation mode and multicarrier OFDM modulation mode, so that transmitting end works in optimal modulation mode, the system and method can dynamically select optimal modulation mode according to intracorporeal channel real-time quality parameter, while ensuring that mode switching is reliably synchronized.

The embodiments of the present application disclose a data transmission method, and an apparatus and a system thereof, which are compatible with the existing DSP framing schemes 400ZR+, 800ZR, and 800ZR+, are more conducive to hardware implementation, and can further be applied to future transmission scenarios using multi-wave or multi-subcarrier transmission, for example, 800 Gbps multi-subcarrier transmission using QPSK modulation, 1.2 Tbps multi-subcarrier transmission using 16-QAM modulation, 1.6 Tbps multi-subcarrier transmission using 16-QAM modulation, or even higher rate transmission scenarios such as 2.4 T / 3.2 T. The method comprises: sending W data frames, the number of symbols comprised in any one data frame in a polarization direction being 87552, each data frame comprising 12 subframes, and the number of symbols comprised in each subframe being 7296, where W is an even number.

The invention relates to a semi-blind phase search method based on target planning in a probabilistic shaping CO-OFDM system. According to the method, a convergence area is set by taking an original constellation point after probability shaping as a center, and a hierarchical target planning strategy is adopted: a first layer takes maximization of signal points in the convergence area as a target, and a second layer takes minimization of a difference degree of probability distribution of a compensated signal and the original constellation point as a target. Meanwhile, test phases are selected by combining a staged test phase estimation strategy in the two-stage blind phase search algorithm, and the common phase noise is compensated by comparing the test phases. Simulation experiments show that compared with a traditional algorithm, the method can effectively suppress common phase noise of various constellation diagrams in different shapes under 16-QAM and 64-QAM modulation, the bit error rate performance is improved under the same signal-to-noise ratio, and meanwhile the spectrum utilization rate is remarkably improved.

The present disclosure proposes a transmitter and receiver for medical applications, wherein the transmitter comprises: an analog front end for receiving an analog signal of a neural electrode; a digital baseband processing module for digitizing and channel coding the analog signal to obtain a coded signal; a modulator for 16-QAM modulation of the coded signal to obtain a modulated signal; 16-QAM modulation is used to improve the scalable data rate; a plurality of target frequency signals are generated by a phase-locked frequency divider, and the target frequency signals are divided into a plurality of target sub-frequency signals; the phase of the modulated signal is adjusted based on the plurality of target sub-frequency signals to obtain a phase-adjusted signal, realizing multi-band data transmission within the transmitter; and finally a power amplifier amplifies the phase-adjusted signal, and the amplified phase-adjusted signal is transmitted to a transmitting unit so that the transmitting unit transmits a signal, realizing high-speed and low-power signal transmission.

The invention relates to the technical field of digital transmitters, in particular to a digital millimeter wave transmitter which comprises a coupler, an orthogonal digital modulator and a digital-analog mixed mode Doherty power amplifier. Wherein the coupler is used for generating a broadband orthogonal signal and inputting the broadband orthogonal signal into the orthogonal digital modulator so as to realize QAM (Quadrature Amplitude Modulation) of the broadband orthogonal signal, and the orthogonal digital modulator inputs the modulated broadband orthogonal signal into the digital-analog mixed mode Doherty power amplifier so as to carry out power amplification on the modulated signal. According to the digital millimeter wave transmitter, through collaborative design of digital modulation and the mixed mode Doherty power amplifier, high system efficiency is achieved under the conditions of high peak-to-average ratio and high-power output, energy consumption is remarkably reduced, a quadrature amplitude modulation (QAM) modulation precision and signal linearity are improved by adopting the quadrature digital modulator and a precise amplitude / phase control mechanism, and the digital millimeter wave transmitter has the advantages of being simple in structure, low in cost and high in reliability. And high-speed data transmission is supported, and the requirement of a 5G system for high-capacity communication is met.

The application discloses a kind of LDPC decoding method based on bidirectional circulation network, belong to communication technical field, including: the 1024QAM signal after transmission by coherent optical system is collected;Discrete channel quantizer suitable for high-order modulation signal is constructed;All bit information is calculated and the uniformity of bit information is completed;Bidirectional information bottleneck decoder is constructed based on bidirectional circulation structure, the check node design of bidirectional information bottleneck decoder;Variable node design of bidirectional information bottleneck decoder.The method utilizes multivariate parameter to construct information bottleneck framework, for all M-QAM modulation format, only need to construct two LUTs extra, can solve the problem that memory requirement increases with modulation order in IB decoding method.In addition, we use bidirectional circulation network and the symmetry of quantized information to realize the multiplexing of table, give full play to the role of intermediate information, make the relationship between the number of LUT search and node degree in IB decoding algorithm from square magnitude to linear magnitude.

The invention provides a wireless communication link high-fidelity simulation method for a high-dynamic Internet of Vehicles, which comprises the following steps of: performing channel modeling by using a channel simulation platform according to an input network layout, a terminal track, a propagation scene and an antenna mode to generate a time-varying channel coefficient; accurate modeling is carried out on key physical phenomena such as multipath propagation, Doppler frequency shift, path gain and propagation time delay in the Internet of Vehicles, and high-fidelity simulation of channel dynamic change characteristics in a high-mobility scene is realized; a transmitter class object, a receiver class object and a channel class object are constructed based on an object-oriented thought, a plurality of processing modules such as QAM modulation, multi-carrier modulation, pilot frequency design, channel estimation and equalization, frequency offset correction and the like are supported, and good transportability and expansibility are achieved. According to the invention, high-fidelity Internet of Vehicles communication system simulation is realized, a communication transceiver signal processing flow is included, and an efficient fidelity verification platform is provided for design and test of an Internet of Vehicles communication protocol and algorithm.

The invention discloses an orthogonal time-frequency-space transceiver suitable for a satellite-ground scene, and relates to the technical field of satellite communication, in particular to the orthogonal time-frequency-space transceiver suitable for the satellite-ground scene. The invention aims to solve the problem that the bit error rate is too high. The method comprises the following steps of: 1, enabling transmission data to sequentially pass through a convolutional coding module, an interleaving module, a scrambling module, a QAM (Quadrature Amplitude Modulation) module, an OTFS (Over the Top File System) module and a CP (Content Program) adding module, and inserting DMRS (Demodulation Reference Signal) into output data of the 2, framing a data symbol, an information symbol and a leader sequence; 3, the framed data sequentially pass through a DAC and an antenna to enter a time-frequency double-selection channel, an antenna on the other FPGA receives a signal, then the signal passes through an ADC to reach a frame synchronization module, output data are sequentially input into CFO frequency offset estimation and correction, symbol synchronization, CP removal, FFT, channel estimation and equalization, inverse two-dimensional Fourier transform, information symbol solution, QAM demodulation, descrambling, de-interleaving and de-convolution coding modules, and then the output data are sent to a frame synchronization module. And the received 01 sequence is obtained.

The application discloses a device for realizing unidirectional multicast function based on G.hn technology, which comprises a G.hn pusher placed in a front-end machine room, a plurality of G.hn receivers placed in a home as user terminals, coaxial cable connections between the G.hn receivers and the G.hn pusher, each G.hn receiver being capable of joining a multicast group with the G.hn pusher as a multicast source, the G.hn pusher sending multicast data to the multicast group for each G.hn receiver in the multicast group to receive, and the multicast data being cable television service data. All G.hn receivers under the coaxial cable can receive, and the number of the G.hn receivers is unlimited. The application breaks the limitation of traditional technology, redefines the G.hn pusher end and the receiver end, adopts OFDM modulation mode to achieve 4096 QAM modulation, realizes transmission of 8K ultra-high-definition video and VR high-quality service, and provides strong technical support for digital transformation of the cable television industry and future network reconstruction.

The present application relates to an adaptive symbol reconstruction method and system for HPLC channel transient interference, first, the received signal in the HPLC channel is acquired and the transient interference feature is extracted, then the manifold dimension is determined according to the QAM modulation order, the tangent space base vector is generated by calculating the partial derivative of the received sample in each dimension, the metric tensor parameter matrix is calculated based on the inner product of the base vector, the interference mapping relationship is established, then the manifold perception generator of the multi-layer LSTM network and the manifold preserving discriminator of the convolutional neural network are constructed, the discriminator and the generator are alternately trained to realize the antagonistic balance, finally, the received signal is reconstructed into the original symbol based on the trained generator, the present application can effectively resist the arc noise interference with the amplitude of 3 times the signal strength.

The invention relates to the technical field of microwave communication, and discloses a microwave communication automatic optimization modulation method based on deep learning, which comprises the following steps of: firstly, transmitting a signal to receiving end equipment by a microwave equipment transmitting end, taking microwave data received by a receiving end as input data, performing initial QAM (Quadrature Amplitude Modulation) grading on the input historical operation data, and then performing data processing on the input historical operation data; the input historical operation data specifically comprises time sequence information of maintenance time, success records and change times; performing data processing and calculation, specifically including classification feature coding, time sequence feature extraction and feature splicing; performing initial probability distribution prediction on the data features; carrying out QAM level selection and feedback updating; and taking the updated historical data and the new operation state as input, repeating the processes of feature engineering, probability prediction, probability adjustment and grade selection, and realizing dynamic adaptive optimization of the QAM modulation grade. According to the method, intelligent switching of modulation levels is realized by automatically and dynamically adjusting the selection probability of a QAM (Quadrature Amplitude Modulation) mode.