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.

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 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 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.

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 .

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.

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 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.