190 results about "Local sequence" patented technology

One embodiment of the present invention provides a system that facilitates loop-free ad-hoc routing in a wireless network. During operation, the system advertises a local sequence number associated with a local node for a destination node, and receives a first route request at the local node, wherein the route request specifies a source node, the destination node, and a first sequence number. The system further selectively maintains a record, which indicates the source node, the destination node, the first sequence number, and a node from which the route request is received. The system also selectively forwards a second route request based on the received route request, wherein the second route request specifies the source node, the destination node, and a second sequence number which is less than the first sequence number and less than or equal to the advertised local sequence number.

The invention provides a method for identifying a reading sequence of a layout, which comprises the following steps of: reading the layout to be identified and analyzing the layout to obtain layout information and object properties of character text objects and image objects; according to the layout information and the object properties, merging the character text objects to form text paragraphs and identifying the image objects into image paragraphs; and determining a reading sequence of the text paragraphs and the image paragraphs by adopting a mode of combining global recursion cutting with local sequence judgment, wherein the global cutting is carried out by projection and for packets which still comprise a plurality of paragraphs after global cutting, a sequence of the paragraphs is judged by adopting a local judging method. Correspondingly, the invention provides a device for identifying the reading sequence of the layout. According to the invention, both characters and images are identified into the paragraphs and the reading sequence of the paragraphs is identified by adopting the mode of combining global recursion cutting with local sequence judgment, so that the correct identification of texts and the images in the complex layout is realized and the efficiency and the accuracy are high.

The invention relates to an anti-interference signal detection and synchronization method for an OFDM system based on cross-correlation detection of a local sequence. A peak value of a cross-correlation value of a received signal and the local sequence is used as a judgment basis for signal detection and system synchronization, compared with delay self-correlation of the received signal, the influence of a signal-to-noise ratio and an interference signal on the cross-correlation value of the received signal and the local sequence is smaller, so that an algorithm can adapt to signal changes, aproblem of frame loss caused by a self-correlation scheme of the received signal can be effectively relieved, and furthermore, the method also has good capability of resisting noise and interference,the phenomenon that a large amount of synchronization errors are generated under the condition that interference and noise exist can be avoided, the robustness is good, and the relevant performance isverified in an actual system.

The invention discloses a multi-carrier synchronizing system and a multi-carrier synchronizing method which are applied to an OFDM multi-carrier system. The multi-carrier synchronizing system comprises a symbol synchronizing module and a frame synchronizing module, wherein the symbol synchronizing module carries out related calculation on a received sequence and a local sequence and determines the symbol synchronizing position by detecting the related peak value of a continuous symbol window, the frame synchronizing module calculates the cumulative sum of the differentials between a phase of a current symbol and an average phase of former symbols, compares the cumulative sum with a preset judgment threshold and finds out the frame synchronizing position after judgment. The multi-carrier synchronizing method comprises the steps of carrying out related calculation on received signals and the local sequence after average filtering is carried out on the received signals, determining the symbol synchronizing position by detecting the related peak value of the continuous window, and judging whether frames are synchronized by calculating the phase differential of two continuous symbols according to the symbol synchronizing position. Compared with the existing synchronizing technology, the multi-carrier synchronizing system and the multi-carrier synchronizing method have the advantages of being low in complexity, high in accuracy and capable of being achieved easily through hardware.

Provided is a single-instruction-set heterogeneous multi-core system static task scheduling method. The method includes five steps: step 1, population initialization; step 2, fitness value calculation; step 3, selection operator operation; step 4, cross operator operation; and step 5 variation operator operation. A local sequence represents an executing sequence of two tasks without depending relations, population initialization efficiency and effective individual are greatly improved, the executing sequence of the tasks is determined through a pre-order-relation matrix, and defects of a traditional height value method are overcome. The method can widen a hunting range of optimal individuals. When the population scale is large enough, a part of optimal solutions missed by the height value method can be found so as to obtain a more optimal scheduling sequence. For the same task set, finishing time of the whole task set is short, power consumption is low, and a purpose of energy conservation and consumption reduction is achieved.

One embodiment of the present invention provides a system that facilitates loop-free ad-hoc routing in a wireless network. During operation, the system advertises a local sequence number associated with a local node for a destination node, and receives a first route request at the local node, wherein the route request specifies a source node, the destination node, and a first sequence number. The system further selectively maintains a record, which indicates the source node, the destination node, the first sequence number, and a node from which the route request is received. The system also selectively forwards a second route request based on the received route request, wherein the second route request specifies the source node, the destination node, and a second sequence number which is less than the first sequence number and less than or equal to the advertised local sequence number.

The invention discloses a detection device and method for gene fusion. The detection method is executed between sequence alignment and local assembly verification and comprises the step of local sequence clustering. The method for local sequence clustering comprises the steps that local clustering is conducted on a second A type sequence which is partially matched with a first position and is also partially matched with a second position of a reference genome and a second B type sequence which is partially matched with the first position and is not partially matched with the second position based on the distance between the first position and the second position, so that a series of first position clusters and a series of second position clusters are obtained; local assembly is conducted on second A type sequences and second B type sequences in the series of second position clusters, so that an assembly sequence is obtained; the assembly sequence is compared with the reference genome again, whether the comparison result of the assembly sequence is consistent with a comparison result for second A type sequences in the second position clusters is checked, if yes, it is proved that the first position and the second position are the gene fusion positions. According to the detection method, the true positive rate is high, and the result is more reliable.

The invention discloses a quick time-frequency synchronizing method under the low signal-to-noise ratio. The method is used for time-frequency synchronization of signals between a transmitting terminal and a receiving terminal. The method specifically comprises the following steps that (1), a linear frequency modulation sequence is used as a spread spectrum sequence of a data package, wherein the cycle is N, and the cycle width is Tc; (2), the linear frequency modulation sequence of one cycle serves as a local sequence, moving correlation is carried out on the spread spectrum sequence of one cycle and the received local sequence from the beginning of time t, a first correlation peak value is obtained, and the position where the first correlation peak value occurs is tp; (3), moving correlation is carried out on the spread spectrum sequence of another cycle and the local sequence from the beginning of time (t+delta T), and a second correlation peak value is obtained; (4), the phase difference delta theta between the first correlation peak value and the second correlation peak value is solved, a frequency offset estimation value fd=delta theta / 2*pi*delta T is obtained to carry out frequency offset compensation on the data package, and the frequency synchronization is finished; (5), the correlation peak value position offset nd=round(fdNTc) is calculated, the initial position of the spread spectrum sequence is tp+ndTc, and time synchronization is finished, wherein the correlation peak value position offset is caused by frequency offset.

The invention provides a frequency synchronization method for an orthogonal frequency division multiplexing system, comprising the following steps of: S102, inserting a first training sequence in a sending signal at a transmission end, and performing inverse fast Fourier transform and associated treatments to the first training sequence as a local sequence stored in a register; S104, inserting a second training sequence in the sending signal at the transmission end, and performing inverse fast Fourier transform and associated treatments to the second training sequence; S106, carrying out coarse frequency synchronization to the received data at a receiving end to attain the coarse frequency-synchronized data; and S108, carrying out the thin frequency synchronization to the coarse frequency-synchronized data to attain the thin frequency-synchronized data. Therefore, estimation range for frequency offset can be efficiently enlarged in the presence of guarantee of good precision, thus diminishing the operation complexity and lessening the system expenditure.

The invention provides an iteration pseudo code acquirer and an acquiring method based on information optimization. The acquirer is composed of six modules. After a signal collected by an A / D sampling module is demodulated by a carrier wave demodulation structure, the signal is sent to a maximum likelihood timing estimator which carries out timing estimation to the timing error of a chip and forms an opening control signal to a multi-sampling arithmetic typical value structure according to a timing estimation result. A multi-sampling arithmetic typical value module starts to work after receiving a starting signal and forms M chip observing quantities to form an observing module data. After the module data is ready, the module data is sent into an iteration message transmission module which executes the operation of iteration message transmission to generate the state vector of a pseudo code sequence and send the state vector of a pseudo code sequence to an acquiring judgment module, and the acquiring judgment module restores a local sequence according to the state vector and carries out relative operation with a received signal to judge whether the acquisition is successful. The iteration pseudo code acquirer can achieve reliable iteration initial information and improve the performance of the rapid acquiring method based on IMPA pseudo codes.

The invention discloses a time synchronization method, which comprises the steps of: carrying out a cross-correlation operation on a received signal and a local sequence, carrying out time weighted average for results of the cross-correlation operation, and determining a symbol timing position based on the results of the weighted average. The method inhibits a peak value of a spurious correlation peak to a certain extent, thereby enlarging a main multipath energy weight, and being capable of obtaining a demanded result, namely the timing position, by operation without searching a maximum value. By adopting the weighted average, the affects of CSD (Cyclic Shift Delay) are further eliminated, and the accuracy of the symbol timing is improved. In addition, because a sequence obtained after displacing and regulating a training sequence is used as a local reference sequence in the embodiment of the invention, the operation can be reduced, the peak value search process is avoided, the synchronous timing position can be rapidly determined, and the system performance can be improved. The time synchronization method is suitable for systems which are different in fluxion and bandwidth.

The invention provides an optical fiber backscattering measurement method and device based on the spread spectrum technology. The method comprises the steps that a sending sequence carries out phase modulation on light source signals through DPSK modulation; DPSK optical signals generated after phase modulation enter an optical path to be measured; DPSK optical signals reflected or backscattered from the optical path to be measured enter a delay interferometer through a first optical directional coupler or an optical circulator, so that demodulation of the DPSK optical signals is achieved; photovoltaic conversion is carried out on the demodulated DPSK optical signals; related despreading is carried out on signals generated after photovoltaic conversion through the local sequence so that optical backscattering measurement can be carried out. According to the optical fiber backscattering measurement method and device based on the spread spectrum technology, by combining the DPSK modulation technology with the spread spectrum technology, the bipolarity of optical domain spreading codes is achieved, the accuracy of optical fiber backscattering measurement is improved, and the dynamic range of optical fiber backscattering measurement is expanded; by modulating the phase of the delay interferometer, code element multiplication in related despreading is achieved, and the electronic bottleneck in electric domain related despreading is overcome.

The invention relates to a decoding method for a low intermediate frequency receiving system in a short-range wireless network. The method comprises the following steps: firstly, receiving a radio-frequency signal transmitted by a transmitting terminal in the short-range wireless network, and directly sampling a low intermediate frequency signal after down-conversion to obtain a baseband receiving signal; carrying out correlative conjugating operation on a local spread-spectrum modulation complex sequence in the short-range wireless network to obtain a group of weight sequences; carrying out up-conversion on a first sequence of the local frequency-expansion modulation complex sequence to low intermediate frequencies; carrying out conjugate multiplication on the low intermediate frequency local sequence and a synchronous low intermediate frequency receiving signal to obtain a correlation value sequence; carrying out correlative operation on every weight sequence with the correlation value sequence respectively to obtain a group of correlation values; and taking the position of the sequence corresponding to the maximal correlation value as receiving demodulation data. The method has the advantages that secondary down-conversion does not need to be carried out on the receiving signal at a radio-frequency terminal, the complexity and the calculation amount of the system are reduced, image interference introduced by secondary conversion is reduced, conjugate multiplication is carried out only on the receiving signal and a first local sequence when decoding, and the calculation amount is reduced.

The invention discloses a detection and estimation method for fine synchronization of a downlink primary synchronization signal in an NB-IoT system. The method comprises the following steps: step (1),acquiring a time domain sampling sequence by an air interface receiver by adopting a sampling rate of 1.92MHz; step (2), performing NPSS coarse synchronization estimation by a terminal receiver; andstep (3), performing second fine synchronization at the sampling rate of 1.92Msps according to time offset and frequency offset results estimated in the course synchronization in step (2), and carrying out self-correlation operation by using an NPSS sequence and a local sequence, wherein the local sequence is generated by using integer frequency offset, and accurate time offset and the integer frequency offset are determined according to a peak position maximum value. The method of the invention has the following beneficial effects: the fine synchronization is that a correlation operation is carried out after an accumulation operation is carried out, so that the storage capacity is reduced; the fine synchronization adopts a pipeline structure based on two adders and one multiplier, so thatthe calculation amount and the storage size are reduced; and the fine synchronization frequency offset estimation stores a group of local sequences and performs iterative updating to replace multiplegroups of local sequences, so that the storage capacity is reduced.

The invention provides a low-complexity timing recovery method in a TDS-OFDM system, belonging to the technical field of digital information processing. The method comprises the steps as follows: intermediate frequency signals are received and sampled by fixed frequency; quasi-baseband complex data is gained by carrying out down transformation on the intermediate frequency sampled signals; the quasi-baseband complex data is re-sampled by an interpolation filter on the basis of decimal delay and sampled enabling signals returned by a loop numerically controlled oscillator; PN correlation is carried out on the re-sampled data to gain the correlation value of the local sequence and the receiving sequence. A simplification error detector extracts timing error information based on the gained correlation value; the timing error information, with noise components filtrated by a loop lowpass filter, is corrected by negative timing error and then input into the numerical control oscillator, and further the decimal delay and enabling signal required by the interpolation filter and a sampler are generated, thus forming a closed loop. The method has the advantages of low complexity, easy realization of hardware circuit and strong compatibility.

The invention discloses a detection method and device of downlink primary synchronization signals in an LTE system. The method includes the following steps that: a frequency deviation value is pre-added to a receiving sequence X (n), so that a sequence Y (n) can be formed through combination; the sequence Y (n) is processed by a low-pass filter, so that a sequence Z (n) can be formed; x-times extraction is performed on the sequence Z (n), m sets of data sequences of which the length is y can be generated; z sets of sequences are selected from the m sets of data sequences, and sliding correlation is performed on the z sets of sequences and one set of local sequence; a maximum value is found out in all operation results of the sliding correlation, the maximum value is compared with a preset threshold value; if the maximum value is larger than the preset threshold value, the maximum value is a correlation peak value, and a time counter is zeroed; if the maximum value is smaller than or equal to the preset threshold value, and the counting of the time counter achieves a full frame cycle, the frequency deviation value is updated, and the correlation peak value is searched again; and the primary synchronization signals are positioned according to the correlation peak value. With the detection method and device of the invention adopted, when large frequency deviation occurs on a system, frequency deviation correction is automatically carried out, and detection of the PSS (primary synchronization signals) can be ensured.

The invention relates to a frame synchronization method capable of resisting single-frequency interference. A sending end is used for adding frame synchronization sequence to a frame header of a physical layer frame, and a receiving end is used for setting a threshold value so as to judge whether a frame start position is detected. The method comprises the following steps: (1) passing a received signal through a low order normalized LMS (Least Mean Square) self-adapting filter; (2) subtracting the output of the low order normalized LMS self-adapting filter from the received signal, so as to obtain a corrected received signal; (3) performing mutual correlation computation of energy normalization to the corrected received signal and the local sequence, so as to obtain a correlation result of energy normalization; (4) comparing the obtained correlation result of energy normalization with the preset threshold value, so as to obtain the start position of the physical layer frame. The method can accurately estimate the start position of the physical layer frame in presence of great single-frequency interference. Therefore, the hardware resource cost is saved, and the system real-time performance is not affected.

The invention discloses a TD-LTE cell search synchronization method based on a CP flat top method. A type of a CP is estimated directly by judging whether a likelihood function of a maximum likelihood estimation based on the CP encounters flat top or not, time delay and decimal frequency offset are carried out by using the maximum likelihood estimation based on the CP according to the type of the CP, frequency offset compensation is carried out on received signals according to the decimal frequency offset, then a PSS time domain sequence is extracted from the received signals according to the time delay, integral frequency offset is estimated, compensation is continually carried out on the received signals through the integral frequency offset to extract an SSS time domain sequence, and the ID of a cell can be obtained through the PSS time domain sequence and the SSS time domain sequence. Therefore, the TD-LTE cell search synchronization method based on the CP flat top method combines a traditional PSS with a cross-correlation method of a local sequence and a self-correlation method of the maximum likelihood estimation based on the CP, and can obtain the type of the CP by judging the flat top of the maximum likelihood function under the situation that the type of the CP is unknown. The TD-LTE cell search synchronization method based on the CP flat top method is low in complexity and easy to implement.

The invention discloses a pulse compression method of a phase-coding modulating signal. The pulse compression method comprises the following steps of: in an echo-pulse compression treatment process of the phase-coding modulating signal, enabling a radio frequency receiving signal to pass through low-pass filters which are connected in parallel in a quadrature demodulating module (1) and a low-pass filter module (2), feeding converted base band signals into a pulse compression module (3), performing pulse compression on the base band data by taking each sampling point as datum, and feeding the pulse compression data value corresponding to the sampling points to a target detecting module (4), performing threshold comparison processing on the pulse-compressed data, outputting target detecting information obtained by threshold comparison to a subsequent information processing unit to complete pulse compression processing of the radar echo signal at one sampling point. According to the pulse compression method disclosed by the invention, by virtue of conjugate point multiplication of the local sequence and the echo signal sequence, the aligned received echo signal is converted into a signal frequency signal, so that a Doppler influence problem of the phase-coding radar echo signal in pulse compression is solved.

The present invention relates to the technical field of wireless communication, in particular to a method and device for detecting a primary synchronization sequence for cell search, which separates the received signals corresponding to the selected antennas to sampling points, and separates the sampling points and local sequences into segments according to an agreed length and complementation; add a phase rotation value to the separated sampling points after segmentation and complementation to obtain multi-channel rotation sequences corresponding to different frequency offset values; correlate the rotation sequences with the three segmented local sequences respectively, and obtain The maximum correlation operation result is output to obtain the correlation operation result of the multi-path rotation sequence; the maximum value among the correlation operation results of the multi-path rotation sequence is taken, and the local sequence corresponding to the maximum value can determine the primary synchronization sequence of the current cell. Since the method and device process the received signal corresponding to each receiving antenna in segments, it no longer needs sample-by-sample sliding correlation, effectively reduces computational complexity, and no longer consumes a large amount of computational resources in extreme environments with large frequency offsets. circuit, operating with low power consumption.

The invention discloses a method for calibrating a local clock through utilization of a short wave time service signal and mainly solves the problem that in the prior art, the hardware complexity is high and the anti-noise performance is low. The method comprises the realization steps of 1), sampling received signals, then transmitting the signals to a DSP chip and multiplying the signals by corresponding points of a local sequence; 2), carrying out Fourier transform on the processed signals, thereby obtaining quasi-signal-to-noise ratios; 3), superposing quasi-signal-to-noise ratios of corresponding positions; 4), calculating a starting point position of the signals through the position of the maximum superposed quasi-signal-to-noise ratio; 5), getting the point from the starting point position of the signals, carrying out segmentation related Fourier transform, thereby determining the length of the received signals; and 6), determining specific time according to the length of the signals and a broadcast time table of the signals and calibrating the local clock. According to the method, a Fourier transform algorithm is utilized, complex filtering does not need to be carried out on the signals, the hardware complexity is greatly reduced, the relatively high anti-noise performance is achieved, and the method can be applied to time synchronization of various radio stations when links are synchronously established among short wave radio stations.

A method of determining the sequence of traversing nodes in a communication network is provided. The method comprises with each node, determining other nodes in the network it can reach in a single hop. Creating a local sequence connection order based on the determined other nodes the node can reach in a single communication hop. Storing historical data of local sequence connection order information and determining a new local sequence connection order based in part on the historical data and communication information.

The embodiment of the invention provides a terminal positioning method and terminal positioning equipment, relates to the field of communication, and aims to reduce resource demand on software and hardware in the terminal positioning process. The terminal positioning method comprises the following steps: segmenting a local sequence corresponding to a subframe of a positioning reference signal (PRS) by a terminal to obtain a segmented local sequence, wherein a starting orthogonal frequency division multiplexing (OFDM) symbol and a finishing OFDM symbol of each segment of the segmented local sequence contain the PRS and the segments of the segmented local sequence are separated by OFDMs which do not contain the PRS; respectively obtaining sub-correlation values of the segmented local sequence and a corresponding received signal in a search window; superposing the sub-correlation values to obtain a correlation value of the local sequence and the corresponding received signal; according to the correlation value, obtaining a reference signal time difference (RSTD), and sending the RSTD to network side equipment so as to position the terminal by the network side equipment according to the RSTD. The terminal positioning method and the terminal positioning equipment are used for positioning the terminal.

A method of determining the sequence of traversing nodes in a communication network is provided. The method comprises with each node, determining other nodes in the network it can reach in a single hop. Creating a local sequence connection order based on the determined other nodes the node can reach in a single communication hop. Storing historical data of local sequence connection order information and determining a new local sequence connection order based in part on the historical data and communication information.

The invention relates to an automatic detection device and method of the geometric quality of a large-sized thin-plate metal workpiece. An overall image and a distance of a thin-plate workpiece are collected at a detection position and the collected image and distance information are transmitted to an image processing unit; the image processing unit obtains the number of processing holes and central positions of all holes, identifies arc and segment pixels, determines the pixel types and the numbers of all types of pixels, and calculates workpiece thickness information; if the hole number, theworkpiece thickness and the hole types meet requirements, a local sensing unit collected a workpiece sequence image and transmits the image to the image processing unit; the image processing unit processes a local sequence image and identifies dimension information and position information of the obtained pixels; and if the pixel dimensions and positions meet requirements, a detection result is outputted. According to the invention, the original image of a to-be-detected workpiece is collected and obtained by means of macro-micro combination and quality detection of the large-sized workpieceis realized; the detection precision is ensured; the restriction on the workpiece dimension is eliminated; and the detection range and the detection precision are improved.

The invention relates to a multi-antenna ranging code detection method in a WiMAX system, including: a multi-antenna conjugate subcarrier on a frequency domain is obtained according to the received the multi-antenna data; the merging and the relating with a local ranging code conjugate sequence are carried out; the detection threshold k1*Pnoise is set according to the noise power Pnoise and is compared with the maximum related power, if small, the further detection is carried out; the inter-code correlated threshold K2*Pnoise is set and is compared with all the related powers, if small, the corresponding multi-antenna ranging code time-biased Tm which is equal to (Theta m / 2 Pi) multiplied by N is calculated, wherein: K1, K2 are constants, the Theta m is the phase angle of the related result of the multi-antenna conjugate subcarrier and the local ranging code conjugate sequence, m is the serial number of the local ranging code, and N is the number of the symbol subcarriers. The method can avoid the respectively relating of each antenna with the local sequence and save the processing time; at the same time, the simultaneously usage of two thresholds can more accurately detect the real ranging code.

An embodiment of the invention discloses a method and a device of anti-frequency-offset detection of a random access preamble. The method comprises the following steps of: dividing a local sequence into a plurality of subsequences according to coherence time of a channel, segmentally taking each section of data of a receiving sequence to carry out correlation calculation with the subsequences of the local sequence, accumulating relevant results of the segments, and judging whether the receiving sequence has a preamble signal according to a final accumulative result. Owing to adopting a method of segmentally carrying out correlation calculation, the obtained correlation value is more precise, leak detection and false alarm probabilities are reduced, and influence of Doppler frequency offset is effectively restrained; the method and the device are suitable for all kinds of channels, operation can be easily implemented, frequency offset estimation and compensation are not needed, and a large amount of resources and time required for calculation and storage are saved.

The invention requests to protect a timed synchronization method for an orthogonal frequency division multiplexing (OFDM) system based on IEEE 802.11ac, and relates to a mobile communication technology, for correctly detecting an initial position under the condition of sending multi-frame data. The method mainly comprises the steps of firstly sampling a received signal, and detecting whether a data size is more than the data size of the minimal frame; then expanding a local sequence in a not very high throughput capacity, and then performing inverse Fourier transform and expansion; and at last associating sampled data with the processed local sequence to form a cost function, so as to correctly detect the initial position of the frame. According to the method provided by the invention, the characteristics of the received signal, an IEEE 802.11ac frame structure and a training sequence of the not very high throughput capacity are combined, so that implementation complexity of a timed synchronization algorithm is reduced, and thus a simple and efficient solution is provided for timed synchronization of the frames.

Sending end executes steps: carrying out time slicing process for the leading sequence of signals in multiple users so that leading sequences of different users use different time slice of a symbol of orthogonal frequency division multiplex (FDM); after carrying out time slicing process for leading sequences, carrying out inverse Fourier transform for the processed leading sequences, then sending out processed result. The receiving end executes steps: carrying out correlation process between local sequence and the received leading sequences; selecting value of window, and reserving correlation values within window of symbol of orthogonal FDM; selecting L pieces of relevant positions of time delay from largest value, where L smaller than or equal to detectable number of path in a channel; or positions of time delay relevant correlation above threshold as information for estimating positions of time delay. Thus, estimation of time delay for multiple users is obtained.