31 results about "DFT matrix" patented technology

An apparatus for transmitting data using a plurality of carriers and method thereof are disclosed, by which PAPR improving effect is enhanced. A method of generating an OFDM signal, which is transmitted by spreading data symbols using a DFT (Discrete Fourier Transform) matrix, according to the present invention includes the steps of generating an output symbol by data-processing the data symbols in time domain in a manner of giving a specific weight to the data symbols and summing up the weight-given data symbols and generating the OFDM signal by performing OFDM data processing on the output symbol.

Provided is a radio communication device which can reduce ISI caused by destruction of an orthogonal DFT matrix even when an SC-FDMA signal is divided into a plurality of clusters and the clusters are respectively mapped to discontinuous frequency bands. The radio communication device includes a DFT unit (110), a division unit (111), and a mapping unit (112). The DFT unit (110) uses the DFT matrix to execute a DFT process on a symbol sequence in a time region to generate a signal (SC-FDMA signal) of the frequency region. The division unit (111) generates a plurality of clusters by dividing the SC-FDMA signal with a partially orthogonal bandwidth corresponding to the vector length of some of the column vectors constituting the DFT matrix used in the DFT unit (110) and orthogonally intersecting at least partially. The mapping unit (112) maps the clusters to discontinuous frequency bands.

An apparatus for transmitting data using a plurality of carriers and method thereof are disclosed, by which PAPR improving effect is enhanced. A method of generating an OFDM signal, which is transmitted by spreading data symbols using a DFT (Discrete Fourier Transform) matrix, according to the present invention includes the steps of generating an output symbol by data-processing the data symbols in time domain in a manner of giving a specific weight to the data symbols and summing up the weight-given data symbols and generating the OFDM signal by performing OFDM data processing on the output symbol.

A communication device providing CSI feedback in a wireless communication system includes a transceiver to receive downlink reference signals and downlink signals including a reference signal configuration. A processor estimates an explicit CSI in the frequency domain. The processor selects a Doppler-delay-beam precoder matrix for a composite Doppler-delay-beam three-stage precoder, which is based on one or more codebooks includingone or more transmit-side spatial beam components,one or more delay components, andone or more Doppler-frequency components,The processor calculates a CQI and / or a PMI and / or a rank indicator, RI, using the explicit CSI and the composite Doppler-delay-beam three-stage precoder, and reports the CSI feedback including the CQI, and / or the PMI and / or the RI. The one or more delay and / or Doppler-frequency components are defined by one or more sub-matrices of a DFT matrix or an oversampled DFT matrix.

The invention discloses a light DFT-S-OFDM secure transmission system based on a digital chaos. The system comprises three encryption steps all together, i.e., insertion of an OFDM synchronous training sequence, DFT matrix signal preprocessing and subcarrier mapping, wherein an OFDM synchronous training sequence and a subcarrier mapping mode are both generated by a chaotic system, DFT matrix element parameters m and n are generated by the chaotic system, by use of initial value sensitivity and pseudo randomness of the digital chaos, encryption processing is performed on DFT-S-OFDM signals, and thus secret transmission is realized. On one hand, since a security system secret key space is huge, the security of high-speed information transmission can be effectively enhanced, and at the same time, since a DFT matrix can substantially reduce a peak average power ratio (PAPR) of OFDM signals, the performance of the transmission system is also improved; and on the other hand, since multiple iteration optimization and multiple discrete Fourier transformation operation are unnecessary in a DFT matrix signal processing system, the whole system has the following advantages: the system architecture is simple, the calculation amount is small, the transceiver cost is low, and transmission of sideband information is unnecessary.

The invention belongs to the technical field of signal processing, and relates to a signal reconstruction method for frequency domain sparse signals. The signal reconstruction method aims to solve the problems that in an existing method, the calculation amount is large, a long time is consumed, a large data memory space is needed, the power consumption is large, the real-time performance is poor and the efficiency is low. According to the signal reconstruction method, based on the symmetry of a discrete Fourier transformation matrix and some characteristics of matrix operation, the method of calculating a sensing matrix in a compressed sensing model is improved, a new method of calculating the sensing matrix is designed and then introduced into fast Fourier transformation, and therefore the calculation amount is decreased and the speed is increased. The signal reconstruction method can be applied to the field of signal processing.

A rate adaptive transmission scheme for MIMO systems, which can transmit a variable number of data symbol streams, provide transmit diversity for each data symbol stream, and fully utilize the total transmit power of the system and the full power of each antenna. In one method, at least one data symbol stream is received for transmission from a plurality of antennas. Each data symbol stream is scaled with a respective weight corresponding to the amount of transmit power allocated to that stream. The scaled data symbol stream(s) are multiplied with a transmit basis matrix to provide a plurality of transmit symbol streams for the plurality of antennas. The transmit basis matrix (e.g., a Walsh-Hadamard matrix or a DFT matrix) is defined such that each data symbol stream is transmitted from all antennas and each transmit symbol stream is transmitted at (or near) the full power for the associated antenna.

The invention relates to a method for recovering signals and frequencies in phase-sensitive OTDR sensing by random monopulse sampling, which is used for signal reconstruction and frequency recovery inphase-sensitive OTDR and comprises the following steps of: (1) determining an observation matrix corresponding to sine signals required in an experiment; (2) determining an observation vector y corresponding to the observation matrix; (3) obtaining a sparse matrix of the signal by using the discrete Fourier transform matrix; (4) carrying out signal reconstruction and frequency recovery on the signal by using an orthogonal matching pursuit algorithm OMP; and (5) transforming the time domain of the signal into the frequency domain through Fourier transform, thereby obtaining the signal and thefrequency. According to the invention, the high-frequency signal can be recovered at a relatively low sampling frequency, so that the sampling and calculating cost of the adopted sensor is greatly reduced.

In an apparatus and method for generating a SC-FDMA signal having a sequence of symbols, a signal is generated by spreading blocks of symbols using a spreading code, then applying an inverse discrete Fourier transform (IDFT) to the symbols, followed by rotating the phase of each symbol, and applying a guard interval in the form of a cyclic prefix (CP), such that the spreading code is selected from sequences having a DFT matrix and Hadamard-Walsh sequence, and whereby the difference between the amounts for rotating the phase of adjacent symbols is constant. The spreading may be changed so as to change the data rate for each transmitter.

A rate adaptive transmission scheme for MIMO systems, which can transmit a variable number of data symbol streams, provide transmit diversity for each data symbol stream, and fully utilize the total transmit power of the system and the full power of each antenna. In one method, at least one data symbol stream is received for transmission from a plurality of antennas. Each data symbol stream is scaled with a respective weight corresponding to the amount of transmit power allocated to that stream. The scaled data symbol stream(s) are multiplied with a transmit basis matrix to provide a plurality of transmit symbol streams for the plurality of antennas. The transmit basis matrix (e.g., a Walsh-Hadamard matrix or a DFT matrix) is defined such that each data symbol stream is transmitted from all antennas and each transmit symbol stream is transmitted at (or near) the full power for the associated antenna.

A method for a user equipment to precode and transmit an uplink signal efficiently in a 2 -antenna system and a method for a base station to receive the transmitted signal efficiently are disclosed. A 2 -antenna codebook includes 4 DFT matrixes and 2 antenna selection matrixes for a rank 1 and one identity matrix for a rank 2 as precoding matrixes. For efficient uplink signal transmission / reception, the present invention provides signal transceiving technology between user equipment and base station using the 2 -antenna codebook.

Techniques are provided that are able to use a substantially smaller number of complex multiplication operations to obtain the same channel estimate than the brute force approach to obtaining the channel estimate. In one approach, an intermediate vector B is first derived (418) based on K subvectors of vector H for channel frequency response estimation and at least two DFT submatrices of DFT matrix W, where K>1. An intermediate matrix A of the DFT matrix is ​​also obtained (420). A least squares channel impulse response estimate is then derived based on intermediate vector B and intermediate matrix A (422). In one implementation, the intermediate vector B is first computed based on the DFT of the matrix HTxL formed by the vector H to provide the matrix GLxL. The inner product between the columns of the basic DFT submatrix W1 and the rows of the matrix GL×L is then computed to obtain the terms of the intermediate vector B.

The invention discloses a direction finding estimation method based on four-order cumulant vectorization DFT. The method comprises the steps that a four-order cumulant matrix is obtained through received signals of a nested matrix and vectorization processing is carried out on the four-order cumulant matrix to obtain a vector z; the z is sorted, redundancy is deleted, and a received signal z1 of acontinuous virtual array element is obtained; a DFT matrix F is constructed, a vector y = Fz1 is calculated, the positions of K maximum peak values of the vector y is obtained, a phase rotation matrix is constructed, an offset phase is obtained through spectral peak search in a small range, and a parameter estimation result is obtained. According to the method, the complexity and the angle estimation performance can be fully balanced, and the limitation that in a traditional sparse array angle estimation method, the angle estimation performance is good but the complexity is high or the calculation complexity is low but the angle estimation performance is low is broken through.

The invention discloses a light DFT-S-OFDM secure transmission system based on a digital chaos. The system comprises three encryption steps all together, i.e., insertion of an OFDM synchronous training sequence, DFT matrix signal preprocessing and subcarrier mapping, wherein an OFDM synchronous training sequence and a subcarrier mapping mode are both generated by a chaotic system, DFT matrix element parameters m and n are generated by the chaotic system, by use of initial value sensitivity and pseudo randomness of the digital chaos, encryption processing is performed on DFT-S-OFDM signals, and thus secret transmission is realized. On one hand, since a security system secret key space is huge, the security of high-speed information transmission can be effectively enhanced, and at the same time, since a DFT matrix can substantially reduce a peak average power ratio (PAPR) of OFDM signals, the performance of the transmission system is also improved; and on the other hand, since multiple iteration optimization and multiple discrete Fourier transformation operation are unnecessary in a DFT matrix signal processing system, the whole system has the following advantages: the system architecture is simple, the calculation amount is small, the transceiver cost is low, and transmission of sideband information is unnecessary.

A parametric generating method for a zero correlation zone sequence set, includes: determining a ZCZ sequence set to be generated; determining a limited symbol set; determining an initial non-periodic orthogonal complementary sequence set; constructing a discrete Fourier transformation matrix by using elements in the limited symbol set; constructing a coefficient matrix based on the number of sequences and the number of iterations in the sequence set; using the columns of the coefficient matrix respectively as the coefficients of each sequence in the ZCZ sequence set, iteratively generating ZCZ sequence sets by using a method of zero filling the tails of weighting coefficients; and traversing the coefficient matrix, and selecting a ZCZ sequence set meeting the criteria or an optimal ZCZ sequence set according to requirements.

The invention provides a pilot frequency information symbol sending method, a channel estimation method and communication equipment. The method comprises the steps: determining a pilot frequency information symbol corresponding to each antenna on each pilot frequency resource according to a discrete Fourier transform (DFT) matrix and a perception matrix; for each antenna, sending a corresponding pilot frequency information symbol on each pilot frequency resource, wherein the sensing matrix is determined through training of channel information. According to the embodiment of the invention, the problem of channel estimation of a large-scale MIMO communication network is solved.

The invention discloses an RF (Radio Frequency) fingerprint database establishment method. The method comprises following steps of discretizing a to-be-positioned region into N detection points; generating an N-order discrete Fourier transform matrix F relative to the N detection points; extracting M lines from the matrix FH according to a preset sampling quantity M, thus forming an M-line N-column observing matrix B with a minimum correlation coefficient; generating an M-dimensional signal feature vector y->arrow according to signal features obtained by measuring the M detection points corresponding to the line mark numbers of the extracted lines; restoring according to the observing matrix B and the M-dimensional signal feature vector y->arrow, thus obtaining the N-dimensional signal feature vector r->arrow of all N detection points in the to-be-positioned region; and establishing an RF fingerprint database according to the signal feature vector r->arrow, wherein the database is used for search and comparison when RF fingerprints are positioned. The invention also discloses an RF fingerprint database establishment device. The workload for establishing and updating the RF fingerprint database can be saved; and moreover, the reliability and accuracy of the restoration results are ensured.

The invention belongs to the technical field of radar, and discloses a low-complexity monostatic MIMO radar non-circular signal angle estimation method, which uses dimension reduction transformation to reduce received data to a low-dimensional space, and then utilizes the non-circular characteristic of a transmitted signal to construct an expanded aperture The received data matrix is ​​obtained; the center conjugate symmetric DFT matrix is ​​used to convert the received data into the beam space, and the complex-valued data covariance matrix is ​​real-valued; the rotation-invariant relationship of the real-valued signal subspace is constructed in the low-dimensional beam space , get the DOA estimate of the target. The present invention utilizes the characteristics of non-circular signals to construct received data extended by virtual array elements for DOA estimation, and uses dimension reduction transform and beam space real-value transform jointly to obtain higher angle estimation accuracy and higher angle estimation accuracy than the conventional ESPRIT algorithm. angular resolution with lower computational complexity.

The invention provides a multi-channel echo filtering method, a filtering device and a readable storage medium. The method comprises steps of resampling through the first audio data and the second audio data; obtaining first time domain data and second time domain data; processing to obtain first inversion time domain data and second inversion time domain data; and then superposing and multiplyingthe MIDFT matrix and the DFT matrix, performing low-frequency phase processing on the first resampling time domain signal and the second resampling time domain signal which are obtained through calculation, finally filtering echo signals, and outputting sound signals after echo filtering. According to the decorrelation method for multiple channels based on resampling, the method is equivalent todelay processing before and after resampling, the correlation before and after signal processing is subjectively controlled through the resampling ratio, the problem based on delay accumulation can besolved through combination of the resampling ratios, and the problem of discontinuity between processing blocks can be solved through signal inversion.

The invention provides a communication method, device and system. The method comprises the following steps: the terminal equipment determines at least one column vector in a first basis matrix as a space domain basis vector; cSI is sent to a network device, the CSI comprises a spatial-domain basis vector index indication corresponding to the spatial-domain basis vector, the first basis matrix is determined according to at least one of a second basis matrix and a first matrix, the second basis matrix is obtained according to N1-K1 rows of a first DFT matrix, and the first matrix is obtained according to the second matrix and / or a third matrix, each column vector of the second matrix includes one or more sets of phase compensation values, and each column vector of the third matrix includes one or more sets of amplitude compensation values. Based on the scheme, the orthogonal DFT basis matrix is corrected, so that the orthogonal DFT basis matrix is suitable for airspace compression of irregular antenna arrays with array irregularity, amplitude offset phenomenon and phase jump phenomenon, and correct communication between terminal equipment and network equipment is guaranteed.

The invention belongs to the technical field of satellite safety communication, and discloses a wireless communication data-carrying AN auxiliary safety transmission method and application, and the method comprises the steps: disturbing a column vector in an original discrete Fourier transform (DFT) matrix by adopting a chaotic pseudo-random sequence, and changing the inherent period of WFRFT, wherein the columns of the chaotic scrambling code WFRFT matrix and the rows of the inverse transformation matrix have orthogonality, different signals are processed by using different columns of the chaotic scrambling code WFRFT matrix, and the processed signals are transmitted as a data carrying AN; and meanwhile, a group of extra ANs are processed by using the column of the chaotic scrambling codeWFRFT and then are sent together. According to the method, the original DFT multiplier is adjusted by utilizing the pseudo-random sequence generated by the chaotic system, so that the hopping of thesubcarrier frequency is realized, and external interference or interception of other parties is effectively resisted; a constellation diagram of the constructed chaotic scrambling code WFRFT combinedsignal generates random splitting, rotation and diffusion, and interception based on a spectral feature recognition means is avoided; detection based on energy and a matched filtering method is avoided.

An apparatus for wireless communication includes a receiver configured to receive control information associated with a non-coherent transmission to a base station. The apparatus further includes a transmitter configured to perform the non-coherent transmission based on the control information. The non-coherent transmission includes transmission of a codepoint to the base station, and the codepoint is determined based a diagonalized base sequence parameter matrix, a first discrete Fourier transform (DFT) matrix of a first size, and a second DFT matrix of a second size.

Techniques to derive a channel estimate using substantially fewer number of complex multiplications than with a brute-force method to derive the same channel estimate. In one method, an intermediate vector B is initially derived based on K sub-vectors of a vector H for a channel frequency response estimate and at least two DFT sub-matrices for a DFT matrix W , where K > 1. An intermediate matrix for A the DFT matrix W is also obtained. A least square channel impulse response estimate is then derived based on the intermediate vector B and the intermediate matrix A . In one implementation, the intermediate vector B is obtained by first computing DFTs of a matrix HTXL , which is formed based on the vector H, to provide a matrix GLXL. Inner products between the columns of a base DFT sub-matrixW1 and the rows of the matrix GLXL are then computed to obtain the entries of the intermediate vector B .

Methods, systems, and apparatus for wireless communication are described. As part of a two-step random access procedure, a user equipment (UE) may transmit a random access preamble to a base station. The UE may generate a preamble by identifying a discrete Fourier transform (DFT) matrix and generating a set of sequences based on the DFT matrix. Each sequence in the set of sequences may be generated by selecting a column of the DFT matrix and performing deterministic sampling on respective entries from the selected column according to a sampling function. The UE may then select a sequence from the set of sequences based on generating the set of sequences. The UE may transmit the selected sequence to a wireless device (e.g., a base station).

An apparatus for wireless communication includes a receiver configured to receive control information associated with a non-coherent transmission to a base station. The apparatus further includes a transmitter configured to perform the non-coherent transmission based on the control information. The non-coherent transmission includes transmission of a codepoint to the base station, and the codepoint is determined based a diagonalized base sequence parameter matrix, a first discrete Fourier transform (DFT) matrix of a first size, and a second DFT matrix of a second size.

The invention provides a PDP estimation method and system in NR based on a TRS, and relates to the technical field of power delay spectrum estimation, and the method comprises the steps: 1, obtaining a frequency domain channel estimation value according to a system instruction; 2, after the frequency domain channel estimation value is obtained, obtaining an observation matrix pi; 3, taking the N-dimensional DFT matrix as a sparse matrix, and obtaining a specific multipath position and multipath power through a compressed sensing algorithm, thereby obtaining accurate PDP estimation; 4, after the observation matrix II is selected in the step 2, the observation matrix II can be obtained by the rest pilot frequencies through the random generation method again, repeating the step 2 and the step 3 again, obtaining PDP estimation, two estimation results being averaged, and obtaining a better estimation result; finally, an observation matrix II is selected in the fourth step, and the PDP estimation frequency is determined according to performance requirements. According to the method, the accuracy of PDP estimation can be improved, the robustness is higher, and the complexity is reduced.

The present invention provides a multi-channel echo filtering method, a filtering device and a readable storage medium, through which the first audio data and the second audio data are resampled, and then the first time domain data and the second time domain data are obtained, and then The first resampled time domain data and the second resampled time domain data are obtained by processing, and then the MIDFT matrix and the DFT matrix are superimposed and multiplied, and the calculated first resampled time domain signal and the second resampled time domain The signal is subjected to low-frequency phase processing, and finally the echo signal is filtered, and the echo-filtered sound signal is output. The multi-channel de-correlation method through resampling makes it equivalent to delay processing based on resampling before and after, and the correlation before and after signal processing is subjectively controlled through the resampling ratio, and based on the delay accumulation problem, the combination of resampling ratios can be used Solve, and can solve the problem of discontinuity between processing blocks through signal inversion.