23 results about "Multipath channels" patented technology

Wireless sensing using measurement enhancement is described. In one example, a described method comprises: receiving a wireless signal transmitted by a transmitter through a wireless multipath channel of a venue, wherein the received wireless signal differs from the transmitted wireless signal due to the wireless multipath channel and a motion of an object in the venue; obtaining a time series of channel information (TSCI) of the wireless multipath channel based on the received wireless signal, wherein each channel information (CI) comprises N1 CI components (CIC); for each respective CI having N1 CIC of the TSCI, computing a respective enhanced CI (ECI) having N2 CIC; computing a motion information (MI) based on the ECI of the TSCI; and performing a sensing task based on the MI.

The invention relates to the technical field of signal processing, in particular to an intelligent blind equalization method and device for large-scale carrier frequency deviation, and the method comprises the steps: carrying out the down-conversion of an original received signal of a preset modulation type, so as to sample an original complex sampling point sequence with large-scale carrier frequency deviation; performing local information exchange, parameter correction and splicing on the original complex sampling point sequence to obtain a compensated complex sampling point sequence; performing pre-extraction and channel amplification on the compensated complex sampling point sequence to obtain pre-extraction features containing implicit channel state information, and further extracting spatial information and time sequence dependence in the pre-extraction features to balance multipath fading of the original complex sampling point sequence and obtain balanced output; and demodulating the original bit information of the original complex sampling point sequence according to the balanced output. Therefore, the problem that a blind equalization method in the related technology cannot effectively adapt to a time-varying multipath channel and a scene with large-scale carrier frequency deviation is solved.

The invention discloses a data transmission method, related equipment, a storage medium and a computer product, the data transmission method is applied to sending equipment, and the method comprises the following steps: obtaining a stable state result of service data of each path in multipath data transmission; and sending the service data of each path and the stable state result of the service data of each path in the multipath channel.

The present invention belongs to the field of unmanned aerial vehicle data transmission, and is a MIMO-OFDM time-frequency synchronization method suitable for unmanned aerial vehicle strong multipath channels. It includes: (1) determining the number of transmitting antennas, the length of the preamble code and the pseudo-random sequence; (2) using the pseudo-random sequence to generate a multi-antenna transmission preamble code sequence; (3) using the multi-antenna preamble code to generate a transmission data frame; (4) correlating the preamble code sequence before and after for coarse time synchronization; (5) performing fractional frequency offset estimation and compensating the received data; (6) calculating the two-dimensional metric function of integer frequency offset estimation and fine time synchronization; (7) jointly performing the strongest path search and integer frequency offset estimation; (8) searching based on the strongest path to obtain a fine synchronization result. The present invention designs an orthogonal preamble sequence independent of the number of antennas at the transmitting end of the unmanned aerial vehicle MIMO-OFDM communication system. The coarse synchronization and fine synchronization algorithms at the receiving end are adapted to multipath channels, are not affected by frequency offset, have a large frequency offset estimation range, and can achieve good synchronization performance.

This invention provides an adaptive method and system for fast spatial spectrum estimation of multipath channels. The method includes: S1, using a linear uniform array as the receiving array, with the first element in the array as the reference element, deriving the broadband signal model and steering vector matrix received by the array; S2, constructing a fitness function, and using the dung beetle algorithm to search for the optimal fractional Fourier transform order of the received signal from the reference element; S3, performing the optimal fractional Fourier transform on the received signal of the array; S4, finding the coordinates (u) corresponding to the maximum value. p ,v p S5. Energy detection: Set a threshold for comparison. If the threshold is met, it indicates that the location of this point is a component of the multipath; otherwise, the algorithm ends. S6. Use the CLEAN algorithm to separate the multipath components. The center frequency of its narrowband filter is u. p S7. Use the MUSIC algorithm to estimate the incident angle of the multipath components; S8. Mask the strongest component among the current multipath components and return to repeat steps S4 to S7 until all components are estimated.

The embodiment of the invention provides a signal sending method and a communication device, relates to the field of communication, and can reduce interference between signals caused by a multipath channel and improve the accuracy of a channel estimation result. The method comprises: obtaining a plurality of extended sequences, each of the plurality of extended sequences comprising an original sequence, a first additional sequence and a second additional sequence, the first additional sequence being a first cyclic sequence or a first zero-padding sequence, the second additional sequence being a second cyclic sequence or a second zero-padding sequence, the first cyclic sequence is a part of the original sequence, and the second cyclic sequence is a part of the original sequence. And generating a first pulse signal according to the plurality of expansion sequences, and sending the first pulse signal.

The application discloses a data transmission method, related equipment, a storage medium and a computer product. The data transmission method is applied to a sending device, and the method comprises the following steps: acquiring a stable state result of service data of each path in multipath data transmission; and sending the service data of each path and the stable state result of the service data of each path in the multipath channel.

The invention relates to a blind equalization method for a deep fading underwater acoustic sparse multipath channel, which belongs to the technical field of channel equalization, and comprises the following steps: acquiring a sending signal transmitted from a sending end to a receiving end through an underwater acoustic channel, acquiring a receiving signal by the receiving end, and sampling the receiving signal through a preset fractional interval to obtain an input signal; constructing a preset fractional interval blind equalizer, and calculating an output signal according to the vector of the input signal and the tap coefficient; the output signal is judged by a decision device to obtain a decision signal, a constellation point mean square error is calculated according to the output signal and the decision signal, the working mode of the preset fractional interval blind equalizer is judged according to the constellation point mean square error and a preset decision threshold, and the tap coefficient is updated according to an error function. And balancing the output signal according to the updated tap coefficient, thereby realizing adaptive suppression of the multipath effect of the underwater acoustic channel, ensuring stable convergence under different channel conditions, and improving the reliability and transmission efficiency of the underwater acoustic communication system.

This invention discloses a pre-equalization compensation method for a terminal in a TDD-OFDM direct conversion system with known transmitter IQI and nonlinear parameters. The method includes: the base station cyclically sending P different training sequences to the terminal; the terminal using a sliding window least squares-based channel state information tracking algorithm to track and estimate the channel state information, where δ is a threshold representing the correlation of the channel within adjacent symbol periods; and pre-equalization compensation performed directly at the terminal. Using the pre-equalization compensation algorithm, a modified data sequence can be obtained and sent to the base station. This invention considers three factors in wireless communication systems: I-path and Q-path imbalance caused by the non-ideal nature of analog components in RF transceivers, power amplifier nonlinearity, and multipath channels. It enables distributed processing within the cell, effectively reducing the demodulation burden on the base station and has wider applicability than traditional compensation methods.

A beamforming design method for intelligent metasurface arrays based on orthogonal time-frequency-space technology includes: aggregating multipath channels under direct illumination into cascaded channels with near-field direction vectors; randomly initializing the phase shift of intelligent metasurface units; establishing an effective channel matrix based on the cascaded channels; then establishing a multi-user and rate objective function; maximizing the objective function through phase shift optimization using a hierarchical search strategy; repeatedly executing the hierarchical search strategy to search and optimize subsequent blocks until the number of intelligent metasurface units in each block reaches a preset value; then performing an exhaustive search in the final block, thus completing one iteration; repeating the iteration until the maximum number of iterations is reached; outputting the final optimal phase shift; and implementing beamforming design based on the final optimal phase shift. This invention can reduce the complexity of beamforming design and ensure reliable transmission of high capacity during high-speed movement.

The embodiment of the invention discloses a communication radiation source identification method and system under a time-varying multipath channel. The method comprises the following steps that: a receiving end receives an OFDM (Orthogonal Frequency Division Multiplexing) signal propagated through a time-varying multipath channel; performing frequency offset correction and timing synchronization on the received OFDM signal, and extracting frequency domain data of an OFDM symbol; performing frequency spectrum cyclic shift division operation on the frequency domain data of each OFDM symbol to generate signal representation; inputting the signal representation as a disordered point set into a point cloud feature extraction model based on an attention mechanism, and extracting modulation features and fingerprint features of a radiation source; and classifying the extracted features through a pre-established multi-task classification network, and respectively outputting a modulation mode identification result and a radiation source individual identification result.

A priority-based centralized multi-AGV multi-path lane change decision planning method, comprising the following steps: S100: according to the pre-established multi-path lane passing rule, reasonably allocate path resources, and confirm the lane change decision result of whether the AGV under the multi-path lane needs to change lane; S200: according to the priority order of each AGV, receive the lane change decision result, plan the behavior level of the current AGV, plan the specific semantic action of lane change, and generate a time-space channel in the cloud for a single AGV. The method can make the multi-AGV system have stronger adaptability and higher efficiency on wide paths, and can reduce congestion and solve sudden situations on wide paths of the multi-AGV system.

The present invention discloses a GMSK receiving method based on blind equalization, comprising the following steps: down-converting the received GMSK signal to baseband; low-pass filtering the GMSK baseband waveform; capturing and synchronizing the received signal based on the pseudo-random sequence in the frame header; equalizing the received GMSK signal using a CMA constant modulus algorithm; derotating the equalized signal; estimating the phase offset of the derotated signal and performing phase compensation; demodulating the soft information, extracting the real part, and making a decision. This method effectively solves the inter-symbol interference problem caused by multipath channels in the current GMSK system, achieving a low-complexity equalization and receiving method suitable for high-speed GMSK transmission.

The invention belongs to the technical field of radar radiation source signal intra-pulse analysis, and particularly relates to an intra-pulse modulation recognition method based on a time-frequency fusion graph and a radar graph convolutional network, and the method comprises the steps: constructing a new physically interpretable graph structured representation mode of a radar signal, and comprehensively utilizing the time-frequency information of the signal to form a time-frequency fusion graph; according to the method, the deep learning-based IPMR algorithm is adopted, and a special hierarchical residual image convolution network-radar map convolution network is specifically designed, so that the method can be directly generalized to a complex multi-path time-varying channel scene, and additional retraining is not needed, and therefore, a fundamental limitation of many existing deep learning-based IPMR methods can be broken through; according to the method, training can be carried out only under the additive white Gaussian noise channel, then time-varying multipath channels with different characteristics are directly adapted, priori knowledge of the channel and retraining on target domain data are not needed, and the method has the outstanding generalization advantage.

This invention discloses a joint estimation method for timing deviation and frequency offset of non-orthogonal multicarrier signals, relating to the field of information and communication technology. The method includes determining an observation window, performing correlation operations on the sampling points of the received signal within the observation window, and obtaining the result of the correlation operation; sliding the observation window and obtaining a timing deviation estimate based on the position of the peak value in the correlation operation result; obtaining multiple sampling points at the positions of the timing deviation estimate, and performing frequency offset estimation on these multiple sampling points to obtain the frequency offset estimate. This invention solves the problem in existing technologies where the non-orthogonal characteristics of the signals in non-orthogonal multicarrier transmission technology lead to inter-symbol interference and inter-subcarrier interference, resulting in a more complex autocovariance matrix of the received signal and making the design of timing deviation and carrier frequency offset estimation algorithms at the receiving end difficult. The proposed algorithm can adapt to different compression factors of non-orthogonal multicarrier signals in multipath channels and achieves better estimation performance.

The application discloses a target detection method based on multi-path component reconstruction residual error, comprising the following steps: step 1: based on the double auto-encoder training algorithm of environmental clutter, learning the clutter structure features in the multi-path channel and reconstructing the multi-path echo; step 2: synthesizing the reconstructed multi-path echo obtained in step 1 into a reconstructed image, based on the target pre-detection algorithm of the reconstruction residual error, comparing the difference between the original image and the reconstructed image, and used for distinguishing whether the to-be-detected region contains target echo. The application fully explores the multi-path characteristics of the clutter, and realizes the weak and small target detection under the condition of no target sample through the multi-path echo reconstruction residual error.

This invention provides a multipath TOA calculation method, system, and electronic device based on a ground-based navigation system. The method includes: acquiring the signal spectrum of the ground-based navigation system transmitted through multiple propagation paths in the frequency domain channel, and constructing a discrete frequency domain channel impulse response model related to the signal spectrum; determining the number of propagation paths of the ground-based navigation system signal based on the signal spectrum; and alternately correcting the arrival time and path amplitude of all propagation paths by gradually increasing the number of propagation paths to a second objective function until the first objective function converges, thereby obtaining the target arrival time and target path amplitude for each propagation path of the ground-based navigation system. This invention improves the accuracy of propagation path number calculation, reduces the probability of false alarms and missed detections in complex multipath channels, and improves the accuracy of propagation path arrival time and path amplitude calculation, thereby improving the positioning accuracy of the entire ground-based navigation system.

A channel equalization method, computer device, and readable storage medium based on a convolutional recurrent neural network belong to the field of communication technologies, and solve the problems of difficult control of convergence error and long convergence process. The method of the present invention includes: collecting and preprocessing a data set, which is divided into a training set, a validation set, and a test set; establishing a channel equalizer based on a convolutional recurrent neural network; determining the parameters of the channel equalizer based on the convolutional recurrent neural network; and equalizing data using the trained channel equalizer based on the convolutional recurrent neural network. The present invention is mainly used in the field of channel equalization for frequency-selective fading channels, especially for channel equalization of Rayleigh multipath channels.

The invention relates to a communication method based on a multipath channel, belongs to the technical field of wireless communication, and solves the problem of poor communication quality of a base station and a mobile terminal in the prior art. The communication method comprises the following steps: determining a plurality of reflecting surfaces according to a base station and a mobile terminal, wherein any two reflecting surfaces form a communication reflecting surface combination; determining a channel model of each communication reflecting surface combination according to the base station and the mobile terminal to obtain each communication channel model; evaluating each communication channel model according to a preset communication quality evaluation index, and selecting an optimal communication channel model; and adjusting communication parameters of the base station and the mobile terminal by using the optimal communication channel model to realize communication between the base station and the mobile terminal. And the communication quality of the base station and the mobile terminal is improved.

This invention discloses a robust method and related equipment for extracting human vital signs information. The method includes: acquiring raw radio frequency data collected by radar; preprocessing the raw radio frequency data to obtain a target data matrix; identifying multipath channels based on the target data matrix; performing parallel phase demodulation on each identified multipath channel to obtain a phase sequence for each multipath channel; performing coherence analysis on the signal components of all phase sequences; adaptively weighting and fusing the phase sequences based on the results of the coherence analysis to obtain a fused vital sign signal; and performing vital sign analysis based on the fused vital sign signal to obtain the target vital sign information. This invention effectively solves the key technical problem of weak vital sign signals being submerged in complex environments through the collaborative processing of multipath signals, enabling high-precision and highly robust non-contact vital sign monitoring, and can be widely applied in the field of radar vital sign monitoring technology.

The invention discloses an intelligent reflection surface (RIS)-assisted AFDM (Amplified Frequency Division Multiplexing) simulation modulation system in a high-speed moving environment, and relates to the field of radio frequency division multiplexing (AFDM) simulation modulation systems. The intelligent reflection surface (RIS)-assisted AFDM simulation modulation system in the high-speed moving environment can be applied to the field of radio frequency division multiplexing (AFDM) simulation modulation of the high-speed moving environment and the high-speed moving environment of the high-speed moving environment and the high-speed moving environment of the high-speed moving environment and the high-speed moving environment of the high-speed moving environment. In the system, the RIS is firstly used as relay auxiliary information transmission from an AFDM transmitting end to a receiving end, and the multipath diversity gain of the system is increased. As a multipath effect and Doppler frequency shift interference exist in high-speed mobile communication, an output solution of an AFDM demodulation end on a discrete affine Fourier domain is solved by constructing a delay Doppler cascade channel of the RIS, and a reflection phase of the RIS is optimized according to the formula, so that the power of a received signal is maximized. As the reflection optimization problem of the RIS under the multipath channel is a non-convex form, the problem can be solved by using a traditional method to cause relatively high complexity. According to the method, the MF-STC method based on norm maximization is provided by deducing the upper limit of the maximization problem to solve the suboptimal solution, and compared with a random phase method, it is verified that the MF-STC method can remarkably reduce the bit error rate of the RIS-AFDM system. Simulation results show that compared with a traditional RIS-assisted orthogonal frequency division multiplexing system, the system scheme provided by the invention can obtain better bit error rate performance.

This invention discloses a wireless multiplexing random access method based on ZC sequences. It employs a waveform design based on ZC sequences and uses cyclic shift index modulation in the time domain to transmit multiple information bits per unit bandwidth. For multi-user access, it allows users to randomly select root sequences for uncoordinated random concurrent access and converts inter-user interference into additive white noise. Addressing the common "root collision" problem in concurrent scenarios, a constellation set matching-based decoding technique is proposed. This technique extracts spectral structure features from multipath channels to construct a reference constellation vector, achieving multi-user signal separation in severe collision and low signal-to-noise ratio environments. To address the sensitivity of ZC sequences to frequency offset, a composite preamble structure is designed. This not only achieves precise decoupling of carrier frequency offset and sampling time offset but also completes coarse- and fine-grained two-level joint estimation and compensation of frequency offset, further ensuring demodulation reliability and concurrent throughput in complex channels.

A method and apparatus are provided for directional communication systems in tactical environments, utilizing frequency-hopping signals to enhance low-probability-of-intercept, -detection, and -geolocation (LPI / LPD / LPG) performance; along with anti-jamming (AJ) performance, multiple access, and performance in multipath channels. Because frequency-hopping signals vary their radio frequency from dwell-to-dwell, this prevents conventional angle-of-arrival (AOA) estimation based on phase-differences. This disclosure presents a technique for AOA estimation for frequency-hopping signals with techniques for combining phase-difference measurements from multiple frequency-hopping dwells to achieve high-performance AOA estimation.