41 results about "Ofdm communication system" patented technology

The invention relates to the technical field of communication interference detection, and particularly discloses an interference detection method based on an OFDM communication system, and the method comprises the steps: S1, signal preprocessing, S2, time-frequency joint analysis, S3, deep learning model construction, S4, multi-interference source positioning, S5, intelligent interference suppression, and S6, interference information feedback. According to the method, Gaussian noise and non-Gaussian interference can be effectively distinguished through a third-order cumulant and other high-order spectrum analysis method, nonlinear features of complex signals can be captured, and the detection accuracy of complex interference is remarkably improved; the combination of the convolutional neural network and the long short-term memory network can automatically extract complex features in interference signals, provide more accurate interference type classification, utilize a beam forming algorithm and a multi-antenna array technology to accurately position a plurality of interference sources, and through a space-time joint estimation method, under the condition of facing the plurality of interference sources, improve the accuracy of the interference sources. And the positioning precision is obviously improved.

The invention discloses a time synchronization method in a multi-rate OFDM (Orthogonal Frequency Division Multiplexing) communication system. The time synchronization method comprises the following steps: S1, forming a training symbol based on a ZC sequence; s2, quantifying the matching degree of a received signal and a synchronous signal in the multi-rate OFDM communication system; s3, performing sliding window energy normalization on the received signal to generate a dynamic detection threshold value; and S4, when the matching degree of the received signal and the synchronization signal is greater than a dynamic detection threshold, detecting the peak position of the synchronization signal, and outputting a timing estimation position to realize time synchronization. According to the method, a ZC sequence synchronization mechanism is expanded to a dynamic bandwidth scene for the first time, the synchronization problem under a complex channel in unmanned aerial vehicle communication is solved through unique characteristics of the ZC sequence, the technical blank of high-maneuverability unmanned aerial vehicle communication is filled, and efficient and high-precision time synchronization is achieved.

An improved non-OFDM communication system and method replaces an FFT at the receiver with an alternative processing configuration. The use of dense subcarriers and assigning A, B pairs based upon a pre-assigned QAM bit-mapped constellation will be maintained as with traditional OFDM. However, the receiver sample-rate is independent of subcarrier frequency-separation, and the system does not maintain separate real and imaginary signals at the transmitter and receiver. The system also processes receiver samples incrementally without awaiting the end of the modulation cycle, and uses incrementally-processed data to characterize disruptions introduced by the channel so as to better adapt to these disruptions. The system has the potential to increase signal throughput by a factor of two by re-using one of the freed-up information paths previously used by the real and imaginary signals.

The invention belongs to the field of unmanned aerial vehicle data transmission, and relates to an MIMO-OFDM time-frequency synchronization method suitable for a strong multipath channel of an unmanned aerial vehicle. Comprising the following steps: (1) determining the number of transmitting antennas, the length of a lead code and a pseudo-random sequence; (2) generating a multi-antenna sending lead code sequence by using the pseudo-random sequence; (3) generating a sending data frame by using the multi-antenna lead code; (4) correlation is carried out before and after the lead code sequence to carry out coarse time synchronization; (5) performing decimal frequency offset estimation, and compensating the received data; (6) calculating a two-dimensional metric function of integer frequency offset estimation and fine time synchronization; (7) jointly performing strongest path search and integer frequency offset estimation; and (8) searching on the basis of the strongest path to obtain a fine synchronization result. According to the method, the orthogonal preamble sequence independent of the number of antennas is designed at the sending end of the MIMO-OFDM communication system of the unmanned aerial vehicle, the coarse synchronization algorithm and the fine synchronization algorithm of the receiving end adapt to a multipath channel and are not affected by frequency offset, the frequency offset estimation range is large, and good synchronization performance can be achieved.

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.

The invention relates to an MIMO windowing OFDM communication system in a high-speed mobile scene and a space diversity utilization method thereof, and the method comprises the steps: dividing a system bandwidth into K subcarriers, and transmitting a signal through M transmitting antennas; modulating a frequency domain signal transmitted by a # imgabs0 # transmitting antenna through OFDM (Orthogonal Frequency Division Multiplexing) to obtain a time domain signal, multiplying the time domain signal by a window function and adding a cyclic prefix; coding the transmitting antenna signal according to the space-frequency repetition code, and transmitting the transmitting antenna signal to a receiving end through a dual-selective channel; receiving signals through N receiving antennas at a receiving end; decoding the received signal by adopting an MIMO (Multiple Input Multiple Output) frequency-varying Viterbi decoding scheme; and iteratively executing solution by using a surround viterbi algorithm in the decoding process until the result converges or reaches the maximum iteration times, thereby obtaining a decoding result and realizing space diversity utilization. By adopting the method, a windowing orthogonal frequency division multiplexing scheme can be expanded to a multi-input multi-output system in a high-speed moving scene, and space diversity is utilized.

The application discloses a kind of FPGA implementation methods for time-frequency synchronization of multi-path parallel transmission millimeter wave OFDM communication system, according to the frame structure of transmission signal physical layer and the number of parallel transmission paths of FPGA implementation time base, training sequence with specific structure is generated in time domain;Correlation operation is carried out on baseband multi-path parallel receiving signal using delay autocorrelation method, and the coarse timing synchronization position is found by the method of flow experience threshold comparison;The angle information carried by autocorrelation result is used to realize the frequency offset estimation calculation of system;The correlation operation is carried out on local cache sequence and receiving signal sequence, and the fine timing synchronization position is obtained;The final system symbol timing synchronization result position index is obtained by adding coarse synchronization and fine synchronization result, and the data sequence after symbol timing synchronization is output;Corresponding complex exponential signal is generated simultaneously, and frequency offset compensation operation is carried out on the sequence after timing synchronization, to complete system synchronization task.The application can improve system synchronization accuracy, reduce hardware implementation time cost and complexity.

The application discloses an FPGA-based adaptive OFDM frequency hopping system and method, and solves the problem of poor anti-interference ability of the current OFDM communication system, which leads to the decline of the system transmission information ability.The application combines the OFDM system with the frequency hopping system, and adds an adaptive control module; the receiver part of the system can detect the quality of the channel in real time, and can change the frequency hopping frequency points and the symbol modulation and demodulation modes of the transmitter and the receiver in real time according to the interference degree, so that the problem of the decline of the transmission information ability is effectively solved, the anti-interference ability of the OFDM communication system is improved, and the transmission reliability is improved.The application can be applied to the field of communication technology.

A method and apparatus are provided for addressing problems in performing FEC decoding in OFDM communication systems, particularly problems associated with SNR fluctuations across the subcarrier frequency band. The disclosed decoding process is based on the use of per-subcarrier SNR values when performing data recovery in a subcarrier group sharing the same modulation format. That is, the bit-wise LLRs created for a given subcarrier are based upon that subcarrier's individual SNR, not an averaged (scalar) SNR used for all subcarriers within a given group.

The application discloses a kind of based on gradient estimation joint optimal solution search underwater acoustic OFDM system carrier synchronization algorithm, belong to underwater acoustic communication technical field.The specific method includes the following steps: step one: in underwater acoustic OFDM communication system, time domain method is used to underwater acoustic OFDM carrier synchronization.Step two: in an OFDM frame, first OFDM symbol is estimated based on optimal solution search carrier synchronization algorithm to carry out frequency offset estimation.Step three: from the second OFDM symbol, gradient descent-based carrier synchronization algorithm is used to estimate frequency offset value, and the frequency offset estimation result of the first OFDM symbol is used as the initial value of iteration.The present application can carry out more fine residual carrier frequency offset compensation by pilot symbol, improve the step of underwater acoustic system carrier synchronization algorithm using Adam method, reduce complexity while improving accuracy, realize reliable and effective underwater acoustic OFDM communication.

The application discloses a time-frequency synchronization method of a non-cooperative OFDM communication system, a blind synchronization algorithm of cyclic prefix autocorrelation is used to perform initial frame synchronization on a received signal to realize frame header positioning, a sliding correlation window is used to position a time domain position of a synchronization sequence of the received signal, clustering decision is performed on the synchronization sequence in continuous multiple frames of signals, and an initial synchronization sequence is extracted through autocorrelation peak value statistics of multiple frame decision results. According to autocorrelation characteristics and cycle characteristics of the synchronization sequence, the application provides a fast symbol synchronization and optimal sampling point synchronization method, and frequency offset estimation is realized based on a Moose algorithm. After the received signal is subjected to time-frequency synchronization, the synchronized sequence is fed back to the clustering decision step to perform iterative updating on a local synchronization sequence, and the overall system performance is further improved.

The invention discloses an OFDM (Orthogonal Frequency Division Multiplexing) communication signal data set manufacturing method based on an FPGA (Field Programmable Gate Array) and programmable interception, solves the problems of few tag dimensions and lack of an OFDM communication system of the existing communication signal data set, and belongs to the field of computer vision. Comprising the following steps: adopting FPGA equipment as a transmitter, a cooperative end receiver and a non-cooperative detection receiver; the channel simulator simulates a channel type, multipath information and Doppler frequency offset required by non-cooperative detection and reception, and respectively sends obtained OFDM communication signals to the cooperative end receiver and the non-cooperative detection and reception machine; using a Kalman filter to clean and retain the intercepted OFDM communication signal meeting the amplitude threshold, calculating the signal power of which the score meets the task requirement, and adding Gaussian white noise to obtain a target OFDM communication signal; the method comprises the following steps: storing an OFDM communication signal data set in a pickle format through python; according to the invention, the production of the OFDM communication signal data set is realized.

The invention discloses a time-frequency synchronization method of a non-cooperative OFDM (Orthogonal Frequency Division Multiplexing) communication system, which comprises the following steps of: performing primary frame synchronization on a received signal by using a cyclic prefix self-correlation blind synchronization algorithm to realize frame header positioning, positioning a time domain position of a synchronization sequence of the received signal by using a sliding correlation window, performing clustering judgment on the synchronization sequence in continuous multi-frame signals, and performing clustering judgment on the synchronization sequence in the continuous multi-frame signals. Counting and extracting an initial synchronization sequence through a multi-frame judgment result self-correlation peak value; according to the self-correlation characteristic and the cycle characteristic of a synchronization sequence, the invention provides a rapid symbol synchronization and optimal sampling point synchronization method, and frequency offset estimation is realized based on a Moose algorithm. According to the method, after time-frequency synchronization is carried out on the received signal, the synchronized sequence is fed back to the clustering judgment step to carry out iterative updating on the local synchronization sequence, and the overall system performance is further improved.

The present invention provides a CP-free PS-OFDM communication system based on an autoencoder, comprising a transmitter, a channel and a receiver; the transmitter comprises a modulation module, a serial-to-parallel conversion module, an inverse Fourier transform module and a transmitter pulse shaping module connected in sequence, the transmitter pulse shaping module comprising a transmitting DNN, the transmitting DNN comprising a transmitting input layer connected to the output end of the inverse Fourier transform module, and a transmitting output layer; the channel is a multipath fading channel; the receiver comprises a receiving pulse shaping module, a coarse equalization module and a demodulation mapping module connected in sequence, the receiving pulse shaping module comprising a receiving DNN, the receiving DNN comprising a receiving input layer for inputting a received signal, and a receiving output layer, the receiving output layer being a receiving PS filter. The present invention can reduce the influence of inter-symbol interference and inter-carrier interference on signal detection, control the time and frequency characteristics of the OFDM signal, and realize flexible configuration of pulse shaping to flexibly support different communication scenarios.

A method for suppressing peak-to-average power ratio (PAPR) of reserved subcarriers in OFDM communication systems includes the following steps: Step 1: digital clipping using a shearing method; Step 2: acquiring clipping noise; Step 3: suppressing out-of-band noise to obtain new clipping noise; Step 4: filtering out in-band noise to obtain canceled noise; Step 5: inversely superimposing the noise into the original signal; Step 6: repeating steps 1-5 to reach the maximum number of iterations; Step 7: outputting the signal after PAPR suppression. This invention expands the range of reserved subcarriers, combining the resources of out-of-band and in-band empty subcarriers, and uses them to generate a signal that suppresses high peak values ​​and cancels noise, thereby improving PAPR suppression gain and retaining the distortion-free characteristics of the reserved subcarrier method.

The invention discloses a self-adaptive channel estimation method and device for a power line OFDM (Orthogonal Frequency Division Multiplexing) communication system. The method comprises the following steps: S1, acquiring an initial frequency domain response estimation value of a current channel; s2, calculating a first channel parameter according to the initial frequency domain response estimation value; s3, calculating a second channel parameter according to the initial frequency domain response estimation value; s4, dynamically determining filtering configuration based on the first channel parameter and the second channel parameter, the filtering configuration comprising an application interval and a filtering order; s5, taking the subcarrier determined by the application interval as a node, and performing channel estimation on the corresponding node subcarrier in a first channel estimation mode according to the filtering order to obtain a node subcarrier channel estimation value; and S6, for non-node subcarriers, performing channel estimation based on the channel estimation values of the adjacent node subcarriers by using a second type of channel estimation mode, thereby realizing the effect of maximally reducing the operand on the premise of not sacrificing the system performance.

The present disclosure describes a method for carrier frequency offset (CFO) estimation of a physical channel in a mobile communication system. The method includes the following steps: performing channel estimation on a received signal on a physical channel based on a plurality of orthogonal frequency division multiplexing (OFDM) symbols in one or more reference signals (RS). The method includes: determining a plurality of phase rotation values Φ and corresponding time differences s between different OFDM symbols in one or more RS within a base phase rotation range including + / −π to obtain a first CFO estimation candidate value f0. Expanding the base phase rotation range to provide an extended phase rotation range greater than + / −π to obtain additional CFO estimation candidate values f1, f2... f n .

To provide an underwater OFDM communication system and a communication method that improve the performance of acoustic wireless communication by performing processing to remove inter-carrier interference on received signals in which the inter-carrier interference has occurred due to disturbance in orthogonality between subcarrier signals that make up an OFDM signal, during OFDM reception processing in reception at a mobile station in a multipath environment with different arrival directions (angles).SOLUTION: An underwater OFDM communication system and a communication method that perform OFDM signal processing in a multipath environment in which OFDM signals transmitted from a transmitting unit that transmits an acoustic signal propagates through two or more different transmission paths underwater and the signals from the different transmission paths are received by a receiving unit in a superimposed state. The OFDM communication system includes means (ADC) for converting the received superimposed signals from an analog signal to a digital numeric sequence at a predetermined sampling frequency Fs, and means (3rdFFT) for performing a discrete Fourier transform on the digital numeric sequence, converting the signal into a frequency domain signal, and analyzing the frequency domain signal.SELECTED DRAWING: Figure 4

The application discloses an OFDM communication signal dataset manufacturing method based on FPGA and programmable interception, solves the problems of few label dimensions and lack of OFDM communication system in current communication signal datasets, and belongs to the field of computer vision; the method comprises the following steps: adopting an FPGA device as a transmitter, a cooperative terminal receiver and a non-cooperative detection receiver; a channel simulator simulates the channel type, multipath information and Doppler frequency offset required by non-cooperative detection, and sends the obtained OFDM communication signals to the cooperative terminal receiver and the non-cooperative detection receiver; a Kalman filter is used to clean and retain the intercepted OFDM communication signals meeting the amplitude threshold, the signal power meeting the task requirement is calculated, Gaussian white noise is added to obtain a target OFDM communication signal; the OFDM communication signal dataset is stored in a pickle format through python; and the application realizes the manufacturing of the OFDM communication signal dataset.

The invention provides a frequency band detection method of an OFDM (Orthogonal Frequency Division Multiplexing) communication system and related equipment. The method comprises the following steps: performing sliding discrete Fourier transform on a received signal sampling sequence to obtain sliding discrete Fourier transform output corresponding to each subcarrier index; constructing a frequency band energy sequence of each candidate frequency band based on the sliding discrete Fourier transform output; defining an adaptive threshold value of each candidate frequency band based on the noise statistical parameter of each candidate frequency band in the preset noise interval; constructing a detection window based on the obtained window starting position; based on the frequency band energy sequence of each candidate frequency band, calculating the detection statistics of each candidate frequency band in the detection window and the corresponding confidence; and if the detection statistical magnitude is greater than the adaptive threshold and the confidence coefficient is greater than a preset confidence coefficient, determining each candidate frequency band as an effective communication frequency band. According to the invention, low time delay, low power consumption and accuracy of communication frequency band detection in the OFDM communication system can be considered.

An improved non-OFDM communication system and method replaces an FFT at the receiver with an alternative processing configuration. The use of dense subcarriers and assigning A, B pairs based upon a pre-assigned QAM bit-mapped constellation will be maintained as with traditional OFDM. However, the receiver sample-rate is independent of subcarrier frequency-separation, and the system does not maintain separate real and imaginary signals at the transmitter and receiver. The system also processes receiver samples incrementally without awaiting the end of the modulation cycle, and uses incrementally-processed data to characterize disruptions introduced by the channel so as to better adapt to these disruptions. The system has the potential to increase signal throughput by a factor of two by re-using one of the freed-up information paths previously used by the real and imaginary signals.

The application discloses an OFDM signal-based underwater acoustic time-varying Doppler estimation method, and belongs to the technical field of underwater acoustic communication and underwater acoustic signal processing. The application is used to solve the problem of realizing joint accurate estimation of relative speed and relative acceleration parameters of a transmitting-receiving party in an underwater acoustic OFDM communication system without improving sampling rate and without complex frequency search, and the time-varying Doppler model containing the speed parameter and the acceleration parameter is constructed by modeling the received signal through nonlinear resampling; the phase and amplitude information is extracted by using the autocorrelation characteristics of adjacent OFDM symbols, the cost function is constructed through multi-branch parallel autocorrelation processing, and the speed and acceleration parameters are jointly estimated by combining the constraint relationship of the phase changing with the symbol serial number. The application can realize joint parameter estimation under the acceleration condition without improving the sampling rate and without large-range frequency search, effectively reduces the system bit error rate, and improves the reliability of the underwater acoustic mobile OFDM communication system.

The invention discloses an electric power cognitive radio NC-OFDM pilot frequency design method and system, and belongs to the technical field of communication, and the method comprises the steps: selecting M pilot frequencies from an available carrier wave set based on an NC-OFDM communication system, selecting a pilot frequency carrier wave position index each time to form an initial pilot frequency vector, taking the pilot frequency vector as an ant matrix, and initializing ant colony algorithm parameters; randomly generating initial positions of ants, and calculating pheromones and a state transition probability matrix of each ant; performing outer loop iteration and inner loop iteration to optimize ant positions; in the iteration process, taking the minimum weighted cross-correlation of a sampling matrix corresponding to a pilot frequency vector as a target, and determining an optimal pilot frequency position index; based on the optimal pilot frequency position index, pilot frequency power is determined according to a minimum cross-correlation method, and a pilot frequency design result of the NC-OFDM communication system is obtained. The performance of the sampling matrix can be improved, and the channel estimation performance is improved.

The present invention relates to an OFDM communication system and method for discrete shared spectrum, and belongs to the field of mobile communication technology. The system includes a transmitting end, a receiving end, and a shared information module. The present invention independently encodes the data carried by each subcarrier in the OFDM communication system and independently adds verification information; the subcarriers of the OFDM time-frequency resource block are continuously allocated in the time domain and discretely allocated in the frequency domain; each subcarrier uses an independent pilot signal and independently performs channel estimation and channel equalization; the time-frequency resource block of the OFDM system adopts a method of first mapping the time domain and then mapping the frequency domain; so that the receiving end can receive the correct data block when there are multiple subcarrier interferences in the OFDM system and the subcarriers in the discrete shared frequency domain are unevenly distributed, thereby making the OFDM system suitable for discrete shared spectrum resource systems.

The present disclosure discloses systems and methods of calculating a near-maximum likelihood detection (MLD) performance capability signal to interference plus noise ratio (SINR) according to instructions stored in non-transitory computer readable memory that when executed by a processor of a multiple-input, multiple output orthogonal frequency-division multiplexing (MIMO-OFDM) wireless communications receiver device cause the processor to perform operations including the processor acquiring Hi and noise variance σn2 for each subcarrier of a set of subcarriers between a MIMO-OFDM wireless communications transmitter device and the wireless communications receiver device, computing an average received bit mutual information rate (RBIR) over all subcarriers, converting the average RBIR to an effective SINR; and selecting a modulation coding scheme (MCS).

The invention discloses an underwater acoustic OFDM (Orthogonal Frequency Division Multiplexing) adaptive communication method based on two-dimensional channel characteristics and an XGBoost classifier, and belongs to the technical field of underwater acoustic communication. The invention solves the problems of high bit error rate and low transmission efficiency of the traditional method. According to the method, the m value obtained through Nakagami-m distribution fitting and the PSNR are used for constructing the two-dimensional channel features as input, the XGBoost multi-classification model optimized through PSO is used for completing modulation mode selection, and therefore finer and more reliable parameter configuration is achieved. By introducing the machine learning algorithm into the adaptive modulation process, the accuracy of modulation coding scheme selection is improved, and the transmission efficiency is maximized while the communication reliability is ensured. The adaptive communication performance of the underwater acoustic OFDM communication system under the condition of the fast time-varying underwater acoustic channel is comprehensively improved from the two aspects of reliability and effectiveness, and the bit error rate of the underwater acoustic OFDM communication system is reduced. The method provided by the invention can be applied to underwater acoustic OFDM adaptive communication.

The invention discloses an RFSoC (radio frequency system-on-chip) low-delay optimization method oriented to a communication sensing integrated system. The method comprises the following steps: firstly, establishing a transmitting link and a receiving link of an OFDM (orthogonal frequency division multiplexing) communication system in a programmable logic PL of an RFSoC; data interaction with a processing system PS is realized by adopting an AXI-based streaming interface; a pseudo-random noise PN sequence is inserted into the initial position of a transmission link in a time division multiplexing mode, and cooperative operation of communication and sensing is achieved; carrying out pipelined delay optimization processing on the transmitting link; dMA data path optimization is carried out on a data transmission path on the PS side, and system-level data paths and signal interface modes of an OFDM transmitting link and an OFDM receiving link are optimized on the PL side. According to the method, the parameterization relationship between communication and sensing performance is constructed, so that the system can select proper PN code configuration according to application requirements, and the performance balance between the communication and sensing functions is realized.

The invention discloses an underwater acoustic OFDM (Orthogonal Frequency Division Multiplexing) system carrier synchronization algorithm based on gradient estimation combined with optimal solution search, and belongs to the technical field of underwater acoustic communication. The method specifically comprises the following steps: step 1, in an underwater acoustic OFDM communication system, synchronizing underwater acoustic OFDM carriers by adopting a time domain method; and step 2, in one OFDM frame, carrying out frequency offset estimation on the first OFDM symbol by adopting a carrier synchronization algorithm based on optimal solution search. And step 3, starting from the second OFDM symbol, estimating a frequency offset value by adopting a carrier synchronization algorithm based on gradient descent, and taking a frequency offset estimation result of the first OFDM symbol as an initial value of iteration. According to the method, finer residual carrier frequency offset compensation can be carried out through pilot symbols, an Adam method is adopted to improve an underwater acoustic system carrier synchronization algorithm of a step length, the complexity is reduced while the precision is improved, and reliable and effective underwater acoustic OFDM communication is realized.

The invention provides a channel estimation and blocking diagnosis method for an RIS (Radio Information System)-assisted MIMO-OFDM (Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing) system, which comprises the following steps of: constructing an RIS-assisted millimeter wave MIMO-OFDM communication system, and blocking a part of RIS elements in the system; designing a frame-based structured training protocol, and modeling a received signal into a low-rank fourth-order tensor; analyzing uniqueness of tensor decomposition, and analyzing conditions which need to be met by a time frame number and a pilot frequency number; decomposing the received signal by using a non-iterative algorithm so as to obtain a factor matrix which is not influenced by a blocking vector and a coupling factor matrix containing residual channel parameters and the blocking vector; and channel parameters and RIS blocking vectors related to all factor matrixes are jointly estimated by using the sparse characteristic of the millimeter wave channel. According to the method, the problems of channel estimation and blocking diagnosis when part of RIS is blocked are solved, RIS blocking and channel parameters can be estimated, and then a cascade channel is recovered through the channel parameters.

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.