77 results about "Semi blind" patented technology

Methods and apparatus for signal processing are disclosed. A discrete time domain input signal x_m(t) may be produced from an array of microphones M₀ . . . M_M. A listening direction may be determined for the microphone array. The listening direction is used in a semi-blind source separation to select the finite impulse response filter coefficients b₀, b₁ . . . , b_N to separate out different sound sources from input signal x_m(t). One or more fractional delays may optionally be applied to selected input signals x_m(t) other than an input signal x₀(t) from a reference microphone M₀. Each fractional delay may be selected to optimize a signal to noise ratio of a discrete time domain output signal y(t) from the microphone array. The fractional delays may be selected to such that a signal from the reference microphone M₀ is first in time relative to signals from the other microphone(s) of the array. A fractional time delay Δ may optionally be introduced into an output signal y(t) so that: y(t+Δ)=x(t+Δ)*b₀+x(t−1+Δ)*b₁+x(t−2+Δ)*b₂+ . . . +x(t−N+Δ)b_N, where Δ is between zero and ±1.

A tracking device may include a body, a sound emitter operable to emit a sound, an array of two or more microphones adapted to produce discrete time domain input signals at a runtime, one or more processors coupled to the array of two or more microphones; and a memory coupled to the microphones and the processor. The memory has a set of processor readable instructions embodied therein. The instructions include one or more instructions for:

determining a listening direction of the sound source relative to the microphone array from the discrete time domain input signals; using the listening direction in a semi-blind source separation to select filtering functions that separate out sounds from the sound emitter from the discrete time domain input signals; identifying a listening zone containing the sound emitter from the filtering functions; and determining a location of the sound emitter from the identified listening zone.

The invention discloses a covariance matching-based multi-antenna spectrum sensing method, which specifically comprises a semi-blind detection method and a complete-blind detection method. In the semi-blind detection method, a new detection amount is constructed by comparing a received-signal sampling covariance matrix with a known noise covariance matrix (herein, the noise covariance refers to noise variance, M refers to the number of receiving antenna, and I[M] refers to a M*M unit matrix); and in the complete-blind detection method, another new detection amount is constructed by the fact that the normalized sampling covariance matrix of a main signal is approximately equal to a diagonal matrix when the main signal does not appear. In the two methods of the invention, because of using correlation as the basis of decision amount of construction, the statistic characteristics of a master user signal and a transmission channel are not required to be known in advance; and especially fora complete-blind detection algorithm based on covariance matching, the spectrum sensing can effectively be implemented under the condition that the noise variance is unknown.

The present invention provides a method for detecting active code channels of multiple users in a wireless communications system. The method comprises the steps of: receiving the radio signals that contain the signals of at least two of said multiple users; separating the data and training sequences of said received radio signals; making channel estimation based on said separated training sequences to obtain the estimated channel response; obtaining, based on said estimated channel response, the active channel response windows; obtaining the allocated spreading codes to which said active channel response windows may correspond; determining, based on the estimated channel responses and the possible corresponding allocated spreading codes, the active spreading code channels corresponding to said active channel response windows; making multi-user detection in the determined active code channels. Thus the blind or semi-blind detection of the receiver is implemented.

In a PRACH channel, colliding signals are resolved by use of a number of training-like symbols in the colliding data payloads. The signals are estimated by spatio temporal filters running a training-based or semi-blind algorithm, and a selection criterion is applied to the estimated signals, such as distance from the finite alphabet or the mean square error.

The invention belongs to the technical field of information and communication, and relates to a semi-blind channel estimation method suitable for a large-scale MIMO system assisted by an intelligent reflecting surface. In order to reduce the pilot overhead of a sending end and improve the channel estimation precision, the invention provides a semi-blind channel estimation method for Bayesian approximate message passing by solving the problem of trilinear matrix decomposition, i.e., only part of sequences in sending symbols are used as pilot symbols. According to the method disclosed by the invention, the maximum calculation overhead of each iteration is only the product operation of the matrix and the vector, the calculation complexity and expandability are relatively low, relatively accurate channel estimation can be obtained under the condition of a small number of pilot frequencies, and meanwhile, unknown symbol sequences of a part of sending ends are detected.

A pneumatic tire has a tread pattern capable of improving wet performance and steering stability in a well balanced manner. An inboard middle land portion is provided with inboard middle axial grooves connecting between an inboard shoulder main groove and an inboard crown main groove and inclined at 20 to 30 degrees. An outboard middle land portion is provided with outboard middle semi-blind grooves extending axially inwardly from a outboard shoulder main groove, and outboard middle sipes extending from the axially inner ends of the outboard middle semi-blind grooves to the outboard crown main groove. The outboard middle semi-blind grooves and the outboard middle sipes are inclined at 20 to 30 degrees. A center land portion is provided with inboard crown semi-blind grooves extending from the inboard crown main groove, and outboard crown semi-blind grooves extending from the outboard crown main groove.

The invention discloses a semi-blind channel estimation method for an intelligent reflecting surface auxiliary communication system, which comprises the following steps that: firstly, a base station sends a corresponding intelligent reflecting surface reflection phase configuration signaling to an intelligent reflecting surface, wherein the intelligent reflecting surface is configured according to the signaling; a user sends a pilot symbol to the base station, and the base station performs initialization estimation on the cascade channel according to a received signal; then, the user sends a data symbol to the base station, and the data symbol is reflected to the base station through the intelligent reflecting surface; the base station firstly calculates a probability density function of a complete data set composed of a received signal and defect data, a log-likelihood function is solved for the probability density function, and by calculating cascade channel estimation when conditional expectation of the log-likelihood function is maximized, an accurate cascade channel estimation value is obtained through iteration. According to the invention, the cascade channel can be estimated by using fewer pilot signals, the pilot overhead of a large-scale intelligent reflector system is effectively reduced, and the communication rate of the system is improved.

A semi-blind MVDR (minimum variance distortionless response) beams forming method belongs to the array signal processing field of a beam former receiving wireless signals. A group of direction vectors with corresponding maximum values sent out from a traditional beam former is adopted to form a minimum variance constraint matrix and define a semi-blind MVDR beam former response vector satisfying the linear constraint and minimum variance constraint; a signal DOA is estimated according to the DOA corresponding to the maximum value of a projection on the semi-blind MVDR beam former response vector by an array receiving vector; a residual vector is defined in virtue of the signal DOA and the array receiving vector and the residual vector is adopted to displace the array receiving vector to repeat the above steps and the repetition time equals the number of signals or the repetition is stopped when the residual signal is less than a certain value. The method realizes the high accurate and high resolution estimation to the DOA when the number of the array receiving vectors is less, thus realizing the high accurate beam forming.

The invention discloses a circularly polarized planar substrate integrated magnetoelectric dipole antenna and an array thereof. The antenna comprises a top metal layer, a first dielectric layer, a middle metal layer, a second dielectric layer, a third dielectric layer and a bottom metal layer which are sequentially arranged from top to bottom. A pair of L-shaped patches which are rotationally andsymmetrically arranged are arranged at the center of the top metal layer; the middle metal layer is a grounding layer, and a rectangular groove is etched in the middle metal layer; and the pair of L-shaped patches and the middle metal layer are electrically connected through a pair of metallized semi-blind holes penetrating through the first dielectric layer. The antenna carries out feeding through the low-profile microstrip feed structure, can be conveniently expanded into an array, and does not need to additionally arrange a dielectric layer to design a feed network. The ground antenna provided by the invention can obtain about 50% of impedance bandwidth, about 8% of 3dB axial ratio bandwidth and wider 3dB axial ratio beam width, and can realize direct integration with a millimeter waveradio frequency front-end circuit.

The invention relates to a reference signal constraint-based mechanical characteristic acoustic signal frequency-domain semi-blind extraction method, and belongs to the technical field of operation maintenance of mechanical equipment. The method comprises the following steps: constructing a multi-scale morphology filter for a failure signal characteristic on the basis of a dynamic particle swarm algorithm with higher global optimization capability, and maximally weakening background noise interference; constructing a reference signal in combination with structural parameters of a mechanical part, and further performing complex component blind separation band by band by virtue of a unit reference signal constraint semi-blind extraction method; solving order uncertainty problems to obtain a separated and restored source signal to finally realize the extraction and separation of the mechanical failure characteristic signal by virtue of the improved KL distance between complex components. Different from vibration monitoring requiring the mounting of a sensor on the surface of mechanical equipment, acoustic monitoring only requires the placement of 1 to 2 microphones around the equipment, and then the failure characteristic signal can be extracted from a picked up mechanical acoustic signal for further failure source positioning.

A receiver performs interference mitigation under blind or semi-blind conditions using diversity present in the signal of interest or in the interferer. A first path interference mitigation procedure extracts training information from received signals, performs interference mitigation on the training information and estimates the channel. The second path interference mitigation procedure uses data extracted from the received signal and the channel estimate to perform interference mitigation. Each interference mitigation process can take the form of a lossy compression followed by decompression.

The invention discloses a semi-blind oversampling clock data recovery circuit with a high locking range, which is mainly used for improving the range of application of the semi-blind oversampling clock data recovery circuit and avoiding generating error code during excessive continuous word time data recovery. The semi-blind oversampling clock data recovery circuit comprises a receiver (1) composed of a multi-path parallel oversampling circuit (11) and a frequency detector FD (12), a data recovery and frequency phase control circuit (2) composed of a filtering and shaping circuit (21), an edge detection circuit (22), a data recovery circuit (23), a phase information circuit (24), a byte adjustment circuit (25) and a frequency/phase adjustment circuit (26), and a feedback circuit (3) composed of a multi-phase VCO (Voltage Controlled Oscillator) circuit (31), a LPF (Low Pass Filter) circuit (32) and an DAC (Digital to Analog Converter) circuit (33). Through the adjustment, the frequency of the sampling clock just can sample the input data, the locking is realized, and the clock data recovery is further accomplished.

The cyclic prefix-based enhanced data recovery method retains the cyclic prefix (CP) upon reception and routes the CP to a data detection module to enhance the operation of the orthogonal frequency division multiplexed (OFDM) receiver whether operating in the blind, semi-blind, training, or perfectly known channel modes. Processing of the OFDM symbol and the CP is performed in the data detector and obtains data recovery by computing a maximum likelihood estimation based on the CP and the OFDM symbols.

The invention relates to an autoclaved fly ash semi-blind porous brick, which is characterized in that the centre of the brick is provided with two square hollow holes, a plurality of semi-blind round holes are arranged at the periphery of the two square hollow holes, and the hollow ratio of the brick is 30-35%; the brick comprises the components of fly ash, bottom slag, lime powder and fine sand, and the weight percentage of each component is as follows: 40-50% of fly ash, 30-35% of bottom slag, 5-12% of lime powder and 10-18% of fine sand. The invention further relates to a preparation method of the autoclaved fly ash semi-blind porous brick. The invention has the advantages of lower production cost of the brick and higher compressive strength, low dry shrinkage and preferable durability of the produced brick.

The present invention provides a short wave area emergency mobile communication semi-blind frequency selection system and a method thereof. From the perspective of detection of communication fusion, the method comprehensively uses the wideband passive monitor and low signal to noise ratio detection technologies. First, a priori scanning frequency in an optimal work frequency is acquired based on full range passive monitoring, so as to prevent electromagnetic pollution caused by full range scanning, so that a basis is provided for bidirectional detection based on existing narrow band short wave radio. Further, the priori frequency is sensed proactively based on a portable short wave radio so as to select preferred frequency. The problems of low communication performance and poor concealment of high-power independent detection are solved, and the method can help improve the short wave area emergency mobile communication in the complex environment.

The invention discloses a fast-convergence semi-blind equalization method which belongs to the field of channel estimation and equalization. The method comprises the following steps: comparing a real part symbol of a current error of an LMS (Least Mean Square) algorithm with a real part symbol of a current error of a MCMA (Modified Constant Modulus Algorithm); if the real part symbols of the two algorithms are the same, utilizing the LMS algorithm to perform real part compensation on the MCMA; comparing a virtual part symbol of the current error of the LMS algorithm with a virtual part symbol of the current error of the MCMA; and if the virtual part symbols of the two algorithms are the same, utilizing the LMS algorithm to perform virtual part compensation on the MCMA. The semi-blind equalization method has a convergence speed higher than that of a blind equalization method. Compared with a linear equalization method, the half-blind equalization method has high convergence precision and higher frequency band utilization rate. And meanwhile, by the adoption of the half-blind equalization method, unreliable error signal caused by LMS algorithm under the condition of inaccurate judgment can be reduced, and the demands of the equalization method on convergence speed and convergence precision can be met at the same time.

The invention provides a semi-blind hole forge piece hole-shrinking forging method. According to the semi-blind hole forge piece forging method, a traditional tool is used for achieving the forge piece hole-shrinking process by changing the deformation process of a material and controlling deformation. The method mainly comprises the following steps of (1) flattening the tail of an ingot and cutting a dead head flat; (2) conducting upsetting; (3) punching a hole with a solid punch pin; (4) broadening the hole through a mandrel until the big-diameter end of a traditional common core rod can penetrate into a blank to be drawn out; (5) drawing out the traditional common core rod to form a preformed blank; (6) erecting the blank to conduct upsetting and smoothening the end faces of the blank;(7) conducting hole-shrinking forming; and (8) conducting surface finishing. Through the method, raw materials are saved; the cost of the raw materials is lowered; the machining allowance is reduced;the machining time is shortened; the production efficiency is improved; consumption during the production process is reduced; the internal metal structure and metal flow line at the intersection of steps of an inner hole of a forge piece are improved, and a continuous metal fibrous structure of the forge piece is maintained after machining; the anti-fatigue performance of the forge piece is improved, and the service life of the forge piece is prolonged.

The invention discloses an half-blind channel estimation method based on an EVD-ILSP The invention relates to a half-blind channel estimation method of an ILSP (International Link Station Protocol), which mainly solves the problem of channel estimation error caused by using a limited number of sample data in the traditional half-blind channel estimation method. The implementation scheme is as follows: 1) enabling a target cell base station to receive a data signal and a pilot signal and solves a covariance matrix of the data signal; 2) performing eigenvalue decomposition on the covariance matrix by adopting an EVD algorithm, and calculating a channel estimation value with ambiguity; 3) using the target cell base station to receive the pilot signal of each user to solve the ambiguity factorestimation value so as to obtain the initial channel estimation value of the target cell; and 4) according to the results of the step 2) and the step 3), obtaining a final channel estimation value byusing an ILSP algorithm. According to the method, the frequency band utilization efficiency of the system is improved, the channel estimation error caused by receiving the data signal by the limitedsample is reduced, and the method can be used for performing channel estimation between the base station signal and the user in a multi-cell multi-user large-scale MIMO system.

The invention discloses a short wave communication semi-blind frequency selection system and frequency selection method based on a CW signal. Passive perception of short-wave full-band interference energy is realized based on a broadband digital multi-channel technology; An energy threshold value is set by using a dial indicator method to judge the interference energy of each sub-channel so as toscreen a prior frequency; A basis is provided for bidirectional detection of high-frequency CW communication; The prior frequency is actively detected based on the short-wave radio station; the priorifrequency is further selected according to a bidirectional detection result to screen out an optimal communication frequency; Therefore, real-time and reliable communication frequency can be providedfor a complex and changeable short-wave communication environment, reliability and real-time performance are improved to a certain extent, meanwhile, equipment is simple, construction is convenient and rapid, and the method has important significance for development and application of a short-wave communication self-adaptive frequency selection technology.