22 results about "Cyclic correlation" patented technology

A federated mining method for multimodal data based on multiple security policies includes: a federated learning framework is used as a data mining model for distributed data mining; a multiple authentication mechanism is designed; a local edge node is selected to participate in a federated computation to obtain authenticated local edge node and aggregate a dataset; a multimodal data fusion and a multimodal data classification are performed on the dataset by a generalized multimodal data feature fusion model based on a multi-headed attention mechanism; and an adaptive perturbation mechanism based on cyclic correlation analysis and differential privacy is designed to add noise round by round and dynamically. A federated mining method for multimodal data is further provided.

The invention relates to the technical field of signal processing, in particular to a joint estimation method and system for time domain parameters of multiple time-frequency overlapped signals, and the method comprises the steps: obtaining a generalized cyclic correlation entropy spectrum of the multiple time-frequency overlapped signals, reconstructing the generalized cyclic correlation entropy spectrum through a compressed sampling matching pursuit algorithm, removing redundant information, and improving the definition and resolution of the spectrum; the speed and precision of spectrum peak searching are improved through an improved grey wolf optimization algorithm, spectrum peak searching is carried out on generalized cyclic correlation entropy spectrum projection, and therefore joint estimation of the carrier frequency and the code element rate is achieved. According to the method, joint estimation and correction of the Cramer-Rao bound in the alpha stable distribution noise environment is deduced, and the method is used for evaluating the effectiveness of the method. When the method is used for reconstructing the entropy spectrum, the influence of impulse noise can be suppressed, so that the reconstructed entropy spectrum is sharper and more gathered; the method has low calculation complexity and higher estimation precision, is suitable for efficient joint estimation of multi-signal time domain parameters, and meets the multi-signal processing requirement in a complex environment.

The application discloses a kind of distributed antenna system joint timing and frequency offset estimation method, it belongs to communication technical field.The application aims to solve the problem of poor real-time performance of existing DAS synchronization method for joint estimation of multiple time offsets and multiple frequency offsets in DAS.The application proposes a method for joint timing and frequency offset estimation in DAS based on the good correlation characteristics of CAZAC sequence and multiple antenna synchronization sequences, which can simultaneously estimate the time offset and frequency offset of different transceiver antenna pairs.The application uses sliding cross-correlation operation and effective peak detection to estimate the time offset and integer multiple frequency offset of different transceiver antenna pairs, and uses cyclic correlation operation to estimate the fractional multiple frequency offset of different transceiver antenna pairs.Furthermore, the application uses simultaneous detection to achieve joint estimation of the time offset and frequency offset of different transceiver antenna pairs, which has low complexity and high real-time performance, and can ensure the accuracy of the estimation result.The application can be applied to timing and frequency offset estimation of distributed antenna system.

The invention discloses a high-speed modulation and demodulation method for a dynamic underwater acoustic network, and the method also employs an orthogonal sequence multiplexing modulation and demodulation technology based on a Zadoff-Chu (ZC) sequence, and combines the setting of a cyclic displacement interval to construct a plurality of sub-channels, thereby achieving the multi-path separation, and reducing the average transmitting power of a system at the same time. In the aspect of multi-user access, interference among multiple users is regarded as additive white noise by using quasi-orthogonal characteristics among different ZC root sequences, so that uncoordinated random concurrent access is supported; differential modulation between sub-channels in a symbol is adopted, and the requirement for phase tracking is lowered; and a receiving end converts multipath amplitude information into soft decision information through cyclic correlation spectrum calculation and multipath diversity technologies, so that the calculation complexity is reduced, and the throughput of the time-varying underwater acoustic system is improved while the multi-user access efficiency is improved.

The present invention belongs to the technical field of communication signal detection, and discloses a method for quickly capturing multi-rate communication signals under low signal-to-noise ratio, mainly solving problems such as slow signal detection speed, single method for selecting statistics, and decreased capture ability in a low signal-to-noise ratio environment when performing time-domain serial capture on signals with different code rates. The implementation steps are as follows: (1) pre-group the possible range of the signal code rate; (2) sample and quantize the received signal; (3) calculate the zero-delay slice of the cyclic correlation of the received signal to estimate the carrier frequency of the signal; (4) intercept the processed signal, slide and select multiple delay slices for accumulation, construct a statistic adapted to the change of the code rate, and perform a rough estimation of the signal code rate; (5) according to the rough estimation result of the code rate, select the best slice of the cyclic correlation to obtain the accurate value of the code rate. The present invention has the advantages of high flexibility and real-time performance, fast capture speed, high capture accuracy, etc., can quickly capture signals in a low signal-to-noise ratio complex electromagnetic environment, and is beneficial to the establishment of a fast communication link.

Embodiments include methods for a radar receiver, including receiving a composite signal corresponding to a transmitted radar signal. The composite signal comprises a plurality (M) of signal streams corresponding to a respective plurality (M) of signal pulses in the transmitted radar signal. Each signal pulse includes a main pulse and a cyclic extension (CE). Each signal stream includes delayed samples corresponding to a plurality of propagation delays of the corresponding signal pulse. Such methods include performing a cyclic correlation of each signal stream with a replica of the main pulse of the corresponding signal pulse, thereby generating a delay-time plane comprising a plurality (M) of correlation streams including samples corresponding to the plurality of propagation delays. Such methods include performing a plurality of DFTs on the correlation streams to generate a delay-Doppler plane. Such methods include searching the delay-Doppler plane for magnitude peaks corresponding to detected objects.

This invention discloses a low-power DTMB transmitter carrier recovery and constellation mapping enhancement method and platform, belonging to the field of terrestrial digital television broadcasting technology. The transmitter samples feedback signals from the intermediate frequency (IF), RF preamplifier, or power amplifier output. Based on the PN420, PN595, or PN945 frame header characteristics, it performs cyclic correlation, sliding correlation, or segmented correlation to obtain frequency offset, phase error, and correlation confidence, and drives a digital phase-locked loop to complete transmitter carrier self-calibration. The system generates non-uniform pre-scaling and pre-rotation parameters based on the feedback constellation error, causing the antenna port constellation to converge to a standard DTMB constellation; enhanced constellation mapping is enabled when supported by a dedicated receiver. The low-power control module reduces power consumption and improves transmission quality based on correlation confidence, EVM scheduling correlator, phase calculation, constellation pre-compensation, digital predistortion, and Doherty power amplifier bias.

An underground slurry communication transmission method belongs to the technical field of petroleum drilling engineering, adopts a cyclic PN sequence for information transmission, and comprises the following steps: 1) generating a group of cyclic PN sequences; (2) at a transmitting end, signals collected underground are mapped to a cyclic PN sequence through a mapping rule, an underground valve is controlled through the cyclic PN sequence to generate pulses, and the pulses are transmitted through a mud medium; and 3) at a receiving end, constructing a cyclic PN sequence receiving system, performing synchronization through a detection means in a matrix form to obtain synchronous bias, performing cyclic correlation operation on a signal and the converted cyclic PN sequence, and resolving information sent by a transmitting end. According to the invention, the cyclic PN sequence is adopted to replace the traditional Marry coding, the defect of low information rate of the traditional coding mode is overcome, and the cyclic PN code can effectively reduce the error rate in the signal transmission process; in the synchronization process, a detection means in a matrix form is adopted, the synchronization accuracy is improved, and it is ensured that underground signals can be accurately and efficiently transmitted back to the ground.

The embodiment of the invention provides a sampling control period calculation method of a self-balancing robot and related equipment. The method comprises the following steps: acquiring a kinetic model and motor control input information of the self-balancing robot; based on the kinetic model and the motor control input information, calculating sampling control description information of the self-balancing robot for any interval moment included in the preset sampling interval; acquiring an instantaneous energy functional, a cyclic correlation energy functional and an interval accumulated energy functional corresponding to any interval moment of the self-balancing robot, and constructing cyclic energy constraint information based on the instantaneous energy functional, the cyclic correlation energy functional and the interval accumulated energy functional; and performing negative qualitative analysis on the cyclic energy constraint information in combination with the sampling control description information, and calculating a sampling control period corresponding to the self-balancing robot. Therefore, the maximum allowable sampling control period can be obtained through calculation, and communication and calculation resources are saved while stable operation of the system is ensured.

The application discloses a kind of integrated signal generation and multi-target clustering identification method and device of feeling.This application uses unified AFDM waveform as bottom transmission mechanism, realizes full diversity gain in time-frequency plane by adjusting affine parameter, effectively suppresses the inter-subcarrier interference under high dynamic scene.In the receiving end, the distance-Doppler heat map is reconstructed by fast cyclic correlation radar algorithm, and the original detection point cloud is extracted combined with 2D-CFAR detection.Introduce the DBSCAN clustering algorithm based on dimensionless weight, and the scattered point is condensed into an independent entity target in RDM physical space, and the radial velocity characteristics of clustering centroid are used to construct automatic decision engine, to realize the real-time classification and identification of static obstacles and dynamic moving targets.The application solves the technical pain points of traditional ISAC system in high frequency, high mobility scene, such as sensing point fragmentation and confusion of static and dynamic targets.

A method of detecting multiple radar targets based on joint radar and communication using OTFS signals is provided. The method includes: generating a range-Doppler map (RDM) based on a first delay-Doppler (DD) domain signal and a second DD domain signal, whereby a first time domain signal is generated from an OTFS modulation based on the first DD domain signal and transmitted to multiple radar targets, and the second DD domain signal is generated from an OTFS demodulation based on a second time domain signal received and reflected from the multiple radar targets from the first time domain signal transmitted; and detecting a dominant radar target amongst the multiple radar targets based on the RDM. In particular, the method further includes, for each iteration of a plurality of iterations: modifying a correlation intermediate term associated with the RDM associated with the iteration based on the detected dominant radar target to obtain a modified correlation intermediate term, the correlation intermediate term relating to a cyclic correlation between the first and second DD domain signals; modifying the RDM associated with the iteration based on the modified correlation intermediate term; and detecting a dominant radar target (i.e., a next dominant radar target) amongst the multiple radar targets based on the RDM modified based on the modified correlation intermediate term. There is also provided a corresponding system for detecting multiple radar targets and a corresponding joint radar and communication system for detecting multiple targets.

The invention discloses a rolling bearing weak fault diagnosis method based on cyclic correlation entropy and a low-rank sparse model, and belongs to the field of bearing fault diagnosis, and the method comprises the following steps: collecting a vibration signal of a rolling bearing, and determining a Gaussian kernel length based on the vibration signal by adopting a Czofmann criterion; based on the Gaussian kernel length, calculating a time-varying correlation entropy of the vibration signal by using a Gaussian kernel function; fourier series transformation is carried out on the time-varying correlation entropy to obtain a cyclic correlation entropy; fourier transform is carried out on the cyclic correlation entropy to obtain a cyclic correlation entropy spectrum; performing low-rank sparse decomposition on the cyclic correlation entropy spectrum by using a truncated kernel norm to obtain a sparse matrix; and solving an enhanced envelope spectrum for the sparse matrix, extracting a fault characteristic frequency based on the enhanced envelope spectrum, and judging a fault type based on the fault characteristic frequency.

The application relates to the technical field of MIMO radars, and discloses a radar waveform combining TDM and DDM, a signal processing method and device and a medium, which comprise a modulated signal transmitting module, a return signal receiving module and a return signal processing module, the application combines the advantages of TDM and DDM, solves the problem of speed ambiguity caused by TDM through slow-time random sampling, the waveform can be well applied to large-scale arrays, avoids speed ambiguity, improves the utilization rate of a Doppler band, a relatively wide Doppler sub-band improves the accuracy of target detection, meanwhile, the application provides a corresponding signal processing procedure for the waveform, and provides a method for separating channels through cyclic correlation using a template, the corresponding target transmitting channels can be quickly and accurately separated, the demand for angle measurement can be met, and the method provided by the application can be compatible with a traditional FMCW radar, and has strong application flexibility.

The invention provides a deception jamming detection method based on sparse recovery. The deception jamming detection method comprises the following implementation steps: constructing a cyclic correlation matrix, an observation vector and a dictionary matrix; constructing a direction of arrival estimation spectrum based on a sparse recovery orthogonal matching pursuit algorithm; and obtaining the direction of arrival angle of each satellite signal and a deception jamming detection result. According to the method, the cyclic correlation matrix is obtained by carrying out cyclic autocorrelation on the data matrix, the cyclic correlation matrix is vectorized to obtain the observation vector, and the direction-of-arrival spectrum is constructed through the observation vector based on the sparse recovery orthogonal matching pursuit algorithm, so that the periodic repetition characteristic of satellite signals is fully utilized; according to the method, the number of snapshots required by the constructed direction-of-arrival spectrum is small, deception jamming detection is carried out by judging the amplitude ratio and the detection threshold in the direction-of-arrival spectrum, the defect that a network model adopted in the prior art is complex in structure is overcome, and the detection efficiency is improved.

The application discloses a kind of mode division multiplexing optical fiber communication signal-to-noise ratio and mode coupling joint estimation method, device and storage medium, mode division multiplexing optical fiber communication signal-to-noise ratio and mode coupling joint estimation method includes obtaining the multiple groups of communication signals of mode division multiplexing optical fiber communication, obtains the spectral correlation function of communication signal, according to spectral correlation function determines cyclic correlation function, according to cyclic correlation function determines signal-to-noise ratio and optical fiber length, according to the signal-to-noise ratio corresponding to each group of communication signals respectively and the optical fiber length, determine power coupling coefficient value etc.Step.The application can monitor signal-to-noise ratio and mode coupling simultaneously, and this kind of joint monitoring capacity can more comprehensively evaluate communication quality, and does not need complex data acquisition or synthetic process, to simplify the implementation and operation of monitoring system, can realize real-time monitoring, guarantee the reliability and timely detection of communication system.The application is widely applied in optical communication technical field.

This application discloses an enhanced high-precision search and capture method for Rowland signals based on convolutional neural networks, comprising: acquiring a target signal sequence within the GRI range of the group repetition period; simulating and generating training data and training a convolutional neural network to obtain a signal search and capture model; using the model to determine whether the signal exists, and if it exists, generating a local pulse group sequence; calculating the maximum value and sampling position of the correlation value sequence through cyclic correlation to determine the signal starting point and complete the search and capture. This method achieves high-precision signal capture under low signal-to-noise ratio by combining neural networks and cyclic correlation.

The invention relates to a Doppler and channel joint estimation method of an OFDM (Orthogonal Frequency Division Multiplexing) system under an impulse noise background, which comprises the following steps of: constructing an OFDM communication system model in which a channel has Doppler frequency shift and a sending signal is an OFDM modulation signal, and then respectively calculating a cyclic autocorrelation function of the sending signal and a cyclic autocorrelation function of a receiving signal in the OFDM communication system model; the method comprises the following steps of: constructing a cyclic correlation matrix equation by using the difference of an OFDM signal, AWGN noise and impulse noise in cyclic correlation function energy distribution, and finally obtaining a Doppler frequency shift estimation value and a channel parameter by solving the matrix equation, thereby realizing Doppler frequency shift and channel estimation of an OFDM system under the impulse noise background. And better robust performance is shown in an impulse noise environment.

The invention belongs to the technical field of communication, and particularly relates to a time-frequency overlapping multi-signal time domain parameter joint estimation method and system under non-Gaussian noise, and the joint estimation is carried out on signal amplitude and time delay through the position and peak value of a discrete spectral line; carrying out spectrum peak position search by adopting a PSO algorithm of a dynamic inertia weight coefficient; deducing the Cramer-Rao bound of time-frequency overlapping multi-signal amplitude-time delay joint estimation under alpha stable distribution noise to carry out effectiveness evaluation; parameter estimation can be carried out on the time-frequency overlapping multi-signal amplitude-time delay joint estimation task based on the cyclic correlation entropy spectrum by using the method provided by the invention; by using the PSO algorithm of the dynamic inertia weight coefficient, the global and local search capability can be enhanced, the situation of local optimum is not easily caused, the effectiveness of the MCRB to parameter estimation is corrected for evaluation, and the performance of the method can be comprehensively and accurately judged; the method has better performance and wider universality.

This invention belongs to the field of large-scale model training and push cluster communication optimization technology, specifically disclosing a network traffic timing orchestration method and system for large-scale model parallel training tasks. The system comprises a topology and traffic acquisition module, a square wave construction module, a conflict calculation module, a scheduling decision module, and an execution module. The method uses sampled cluster communication link occupancy and a link task square wave constructed using the periodicity and temporal dependence characteristics of large-scale model training as input. It utilizes the cyclic correlation between cluster communication link occupancy and the link task square wave to characterize the link conflict state under different timing offsets. By introducing a signal change rate index, it selects the optimal timing offset to orchestrate the training task, thereby improving the utilization rate of link resources. This system can be integrated as a pluggable module into the cluster physical resource scheduler to further reduce cross-node communication conflicts.

The application discloses a method, system, device and medium for identifying MIMO-OFDM space-frequency coding mode under alpha stable distribution noise, which comprises the following steps: firstly, performing space-time-frequency coding inter-class identification based on fractional low-order correlation on a received signal; then, extracting a cyclic correlation entropy spectrum feature map of the received signal; and finally, inputting the extracted feature map into a trained deep forest network to identify the space-frequency coding mode; the system and device are based on space-time-frequency coding inter-class identification based on fractional low-order time lag correlation, inter-class identification of unknown signals is realized, and whether space-frequency coding is used is confirmed; the application extracts a cyclic correlation entropy spectrum feature map of a received signal, combines a deep forest network, and converts a coding identification problem into an image identification problem; the application can effectively identify MIMO-OFDM space-frequency coding mode under alpha stable distribution noise, solves the problem that a traditional method is limited in function in non-cooperative communication, and is also applicable to a Gaussian noise environment.

A method of radar sensing for detecting multiple targets is provided. The method includes: determining a channel estimation or a cyclic correlation based on a received signal and a transmitted signal, whereby the received signal is reflected from multiple targets from the transmitted signal and the cyclic correlation is determined based on a correlation intermediate term; determining a range-Doppler map based on the channel estimation or the cyclic correlation; and detecting a dominant target amongst the multiple targets based on the range-Doppler map determined based on the channel estimation or the cyclic correlation. In particular, the method further includes, for each iteration of a plurality of iterations: determining a first dominant target attributed channel estimation or a first dominant target attributed correlation intermediate term based on the detected dominant target; modifying the channel estimation or the cyclic correlation including offsetting the first dominant target attributed channel estimation from the channel estimation or offsetting the first dominant target attributed correlation intermediate term from the correlation intermediate term; determining a range-Doppler map based on the modified channel estimation or the modified cyclic correlation; and detecting a next dominant target amongst the multiple targets based on the range-Doppler map determined based on the modified channel estimation or the modified cyclic correlation. There is also provided a corresponding system for radar sensing and a corresponding radar for detecting multiple targets.

The invention discloses a combined timing and frequency offset estimation method for a distributed antenna system, and belongs to the technical field of communication. The objective of the invention is to solve the problem of poor real-time performance of joint estimation of multi-time offset and multi-frequency offset in the DAS by the existing DAS synchronization method. The invention provides a method for combining timing and frequency offset estimation in the DAS based on good correlation characteristics of a CAZAC sequence and a multi-antenna synchronization sequence, and time offset and frequency offset estimation of different receiving and transmitting antenna pairs can be realized at the same time. Sliding cross-correlation operation is adopted and effective peak detection is carried out, time offset and integer frequency offset estimation of different receiving and transmitting antenna pairs is realized, and cyclic correlation operation is adopted to estimate decimal frequency offset of different receiving and transmitting antenna pairs. Moreover, the method employs a simultaneous detection thought, can achieve the joint estimation of the time offset and frequency offset of different receiving and transmitting antenna pairs, is lower in complexity and higher in real-time performance, and can guarantee the accuracy of an estimation result. The method can be applied to timing and frequency offset estimation of a distributed antenna system.