150 results about "Golay sequence" patented technology

Method for forming and determining a signal sequence, a synchronization method, a transmitting unit and a receiving unit, including the formation of signal sequences that are based on partial signal sequences, the second partial signal sequence being repeated and modulated in the process by the first partial signal sequence, and at least one of the signal sequences being a Golay sequence, and use of these partial signal sequences for the purpose of simplified calculation of correlation sums in a two-stage calculation method, with one partial correlation sum sequence being calculated first.

A preamble for a reverse access channel (RACH) of a CDMA (code division multiple access) communications system comprises a pair of constituent Golay sequences A and B concatenated with at least one pair, and preferably a plurality of different pairs, of transformed sequences which are also constituent Golay sequences, each pair of transformed sequences comprising a permutation of elements of the pair of sequences A and B. The permutations can include a reversed order of elements in the sequences, a reversed order of some or all of a set of address bits identifying locations of elements in the sequences, a concatenation of subsets of elements in odd and even locations of the sequences A and B, and combinations of these permutations. A method for providing the preamble, and related apparatus using a bidirectional counter and an address permutation unit, are described.

The invention discloses a method for generating a variable parameter chaotic signal, and a chaotic secure communication system. The method comprises the following steps: firstly, chaotic mapping is used to generate the chaotic signal; then a parameter set of the chaotic mapping is determined in advance, so as to process any pseudorandom signal, and enable the state of the pseudorandom signal and the elements of the parameter set to be in one-to-one correspondence; and a corresponding parameter is chosen to generate the variable parameter chaotic signal by chaotic mapping according to the state of the pseudorandom signal. The system comprises a chaotic signal generating module, an analog-to-digital conversion module, a parameter transformation module, a coding module, a multi-path choice switch, an encryption / decryption module, an encrypted message data cache, a plaintext data cache and a control module. The invention can increase the complexity of the output of the chaotic signal or a chaotic sequence, and effectively resist the analysis of the nonlinear prediction technology based on phase-space reconstruction. The output digital chaotic sequence can be taken as a pseudorandom number sequence or key stream to encrypt data; the output continuous chaotic signals can be used for designing a secret communication system based on chaos synchronization .

A method and system for performing sequence time domain reflectometry over a communication channel to determine the location of line anomalies in the communication channel is disclosed. In one embodiment, the system generates a sequence signal and transmits the sequence signal over an optical channel. The system receives one or more reflection signals over the optical channel and performs reflection signal processing on the reflection signal. In one embodiment, the optical reflection is transformed to an electrical signal and correlated with the original sequence signal to generate a correlated signal. The time between the start of the reflection signal and a subsequent point of correlation and the rate of propagation reveals a line anomaly location. A circulator, beam splitter, or any other similar device may direct the reflection signal to the apparatus configured to perform reflection signal processing.

A method describes activity in a video sequence. The method measures intensity, direction, spatial, and temporal attributes in the video sequence, and the measured attributes are combined in a digital descriptor of the activity of the video sequence.

The present invention teaches a system and method for secure network access and group membership in a cooperative network of digital chaos transmissions. The invention involves sensing generated digital chaos sequences as spreading sequences at a transmit side and determining the availability of open channels at a receive side. Further, a broadcast “request to join” frame from a node on an open channel is transmitted to network manager or coordinator. A network manager or coordinator sends an association / authentication packet, comprised of the reserved digital chaos associated to the unique device id, in response to the “request to join” frame from a node with a valid identification.

Embodiments of the invention provide a method to detect DSSS preambles in smart utility networks. A DSSS signal is received by a receiver and a digital sequence of samples is formed. A difference value is calculated between pairs of samples in the digital sequence of samples to form a sequence of differential values. A known preamble differential value sequence is correlated with the sequence of differential values to form a sequence of correlation values. A location of the preamble is located in the digital sequence of samples corresponding to a peak in the sequence of correlation values that exceeds a threshold value.

In a telecommunications system that employs frequency hopping techniques, network performance can be significantly improved by taking into consideration the level of interaction (e.g., the collision rate) between frequency hopping sequences, when allocating the frequency hopping sequences throughout the network. In a cellular network, this may be accomplished by deriving a network performance measure as a function of a current allocation of frequency hopping sequences for a number of cells and as a function of an expected collision rate (between the frequency hopping sequences) that appear for the current allocation. The frequency hopping sequences are then re-allocated amongst one or more cells until network performance is optimized. The allocation of frequency hopping sequences that results in optimized network performance may then be used for assigning frequency hopping sequences to new or existing connections (e.g., cellular calls) within a corresponding cell.

In encoding and decoding video signals, a progressive video bitstream is received which has reference frames and non-reference frames, each having an initial temporal reference in accordance with an initial frame sequence structure. The temporal references of the only the reference frames are remapped, by ignoring the non-reference frames. The reference frames are packetized with a base packet-identifier (PID) and the non-reference frames with an enhancement PID, to provide base and enhancement transport bitstreams, respectively.

In one embodiment, a Walsh-Hadamard decoder can have a hardware efficient Fast Hadamard Transform (“FHT”) engine. In one embodiment, the FHT engine can include an input to receive an input sequence to be decoded into a Walsh-Hadamard codeword. The FHT engine can further include a controller to correlate the received input sequence with a plurality of Walsh-Hadamard codewords using two add / subtract modules. In one embodiment, the two add / subtract modules operate in parallel.

Future media viewership is forecast based on time ordered analysis of historical viewership information from an individual or combination of a plurality of data sets. Forecast models having coefficients derived from comparisons of time series representations of data sets across a plurality of time periods and data sources join together disparate data sets. Individual data sets from disparate data sources may be compared to identify possible untrustworthy data or data that requires further investigation. Organizing viewership information in a time series allows for imputing missing data in a respective data set.

The invention relates to information security technology, in particular to a virtual genome-based cryptosystem (VGC). The cryptosystem is provided with two matched keys, of which one is a virtual genome database (VGDB) consisting of random deoxyribonucleic acid (DNA) sequences and the other one is a position table that virtual genes of the VGDB are randomly distributed in a two-dimensional microarray, namely a virtual DNA microarray chip (VDMC). Any plaintext information can be freely written on the VDMC, namely points for forming the plaintext information are selected from the VDMC microarray. The selected points correspond to the virtual genes in the VGDB; small segments of DNA sequences are randomly selected from the virtual genes; and the uniqueness of the small segments of DNA sequences in the VGDB is determined by using a common tool of the bioinformatics, namely a basic local alignment search tool (BLAST), or other character string search algorithms such as a Knuth-Morris-Pratt (KMP) algorithm and the like. A cipher text is combined by the small segments of DNA sequences. The small segments of DNA sequences need only to perform BLAST on the VGDB during decryption, namely the points for forming the plaintext information can be discovered, and the plaintext information can be restored according to the VDMC. Any non-VGDB sequence can be randomly inserted into the cipher text and does not have any influence on the encryption. Thus, the VGC is an excellent information hiding system. In addition, the VGC key can be updated automatically so as to realize an indecipherable one-time-pad system. The cryptosystem is used for real-time quick secret information communication, digital signature and identity authentication.

The invention provides an initial cell searching method of LTE (Long Term Evolution) under a high-speed mobile condition, comprising the following steps of: acquiring the position of a master synchronous signal and the ID number of a cell in a receiving sequence; carrying out frequency offset estimation and compensating, and demodulating the master synchronous signal to a frequency domain; carrying out channel estimation by utilizing the data information of the master synchronous signal; and carrying out coherent demodulation on an auxiliary synchronous signal according to the ID number of the cell and the channel estimation result of the master synchronous signal to acquire the ID group number of the cell. In a high-speed mobile specific scene, downlink synchronization is simply and quickly acquired by using the method, and the frequency offset can be estimated. Although the method has some restrained conditions, the conditions can be satisfied in the specific scene, and the algorithm complexity can be effectively lowered.

A shot analyzer varies the resolution when generating encoded video sequences for streaming. The shot analyzer generates a first encoded video sequence based on a first resolution and a source video sequence that is associated with a video title. The shot analyzer then determines a first encoded shot sequence from multiple encoded shot sequences included in the first encoded video sequence based on quality metric(s). The first encoded shot sequence is associated with a first shot sequence included in the source video sequence. Subsequently, the shot analyzer generates a second encoded shot sequence based on a second resolution and the first shot sequence. The shot analyzer generates a second encoded video sequence based on the first encoded video sequence and the second encoded shot sequence. At least a first portion of the second encoded video sequence is subsequently streamed to an endpoint device during playback of the video title.

A signal generating apparatus, which is adapted for outputting a multicarrier signal where data are multiplexed with respect to a plurality of subcarriers, includes: a rotation sequence selection signal generator for generating a plurality of rotation sequence selection signal sequences which vary the phase relationship between subcarriers on the basis of a plurality of phase rotation sequences and include the number of samples, which are smaller than that of actual transmission signals; and a minimum peak power signal generator for selecting a signal of which peak power becomes minimum from the plurality of rotation sequence selection signals to generate an actual transmission signal by using a phase rotation sequence multiplied with respect to the selected signal.

A system controls a transmission of a sequence of compressed video data from an encoder buffer to a network for delivery to a decoder buffer. Control of the transmission includes to: determine characteristics of a video transmission path between the encoder buffer and the decoder buffer, the characteristics comprising at least one of a buffer size of the decoder buffer, an input rate of the decoder buffer, and a buffer size of an equivalent intermediary buffer of the video transmission path; determine a transmission rate from the characteristics of the video transmission path and from the sequence of compressed video data, the transmission rate being determined such that a target quality of service value can be guaranteed for the entire sequence of compressed video data transmitted at the determined transmission rate to the decoder buffer; and control transmission of the sequence of compressed video data at the determined transmission rate.

The invention provides a composite chaotic secondary scrambling image encryption algorithm and belongs to the technical field of encryption. The algorithm is characterized by, to begin with, generating an initial value of Logistic mapping through Chebyshev mapping; then, forming a two-dimensional chaotic matrix through the Logistic mapping; and carrying out position and grayscale secondary scrambling on images needing encryption through the matrix. The algorithm utilizes Chebyshev mapping and Logistic mapping to alternately generate mixed chaotic sequences, thereby not only inheriting characteristics of the single Logistic mapping chaotic sequence, but also improving the phenomenon of stable window of the single chaotic sequence; in comparison, random performance of the sequence is higher;and in particular, the system is very sensitive to encryption keys, and subtle changes in the keys will directly lead to changes in the location and grayscale matrix, so that decryption fails, and the system has higher safety.

The invention provides a direct sequence spread spectrum modulation method for suppressing multipath interference in underwater acoustic communication. According to the direct sequence spread spectrum modulation method, a complementary sequence pair is introduced to underwater acoustic communication as a pseudo-random sequence of direct sequence spread spectrum modulation, better multipath suppression capability than that of an ordinary finite-length random sequence is achieved by using an ideal correlation function constructed in a zero correlation window, and multipath interference in underwater acoustic spread spectrum communication can be suppressed completely. According to the actual need, a pseudo-random sequence of direct sequence spread spectrum modulation can be constructed by combining two types of 'complementary sequence' pairs. By adopting a time-division orthogonal combination mode, the emission duty ratio can be reduced, and an effect of power amplifier cooling can be achieved. A signal is not sensitive to carrier phase when demodulated in an orthogonal mode, and no precise carrier phase synchronization is needed. The efficiency of information transmission by a carrier phase orthogonal combination mode is consistent with spread spectrum modulation of ordinary m sequences, Gold sequences and other pseudo-random sequences. The method has high demodulation bit error rate at high signal-to-noise ratio.

The invention relates to a method, a device and a synchronous system for sending and receiving synchronous information; wherein, the method comprises the steps as follows: a plurality of different groups of long complementary Golay sequence pairs are generated by short complementary Golay sequence pairs; long complementary Golay sequence pairs are selected out of a plurality of different groups of long complementary Golay sequence pairs and distributed to all transmitting antennas; time-domain synchronous sequences are generated according to all selected complementary Golay sequences; orthogonal frequency division multiplexing modulation (OFDM) is carried out on the time-domain synchronous sequences so as to generate OFDM symbols; the OFDM symbols are respectively sent by all corresponding transmitting antennas after cyclic prefix (CP) is added. The method, the device and the system can be used for the synchronization of distribution-typed multi-antenna OFDM systems; adjacent districts are not easy to be disturbed by each other; accuracy of time delaying and frequency offset estimation is improved, the realization is simple and the stability of match performance is high.

The embodiment of the invention provides a video data decoding method and device, and the method and device are used in the Internet of scenes. The method comprises the steps: receiving a video sequence sent by a node server, wherein the video sequence comprises an intraframe coding frame; and judging whether packet loss happens to the intraframe coding frame or not: abandoning the video sequence if the packet loss happens to the intraframe coding frame, or else, carrying out the decoding of the intraframe coding frame. According to the embodiment of the invention, the method guarantees the integrity of the video sequence, and avoids the mosaic phenomenon during video playing.

A receiving system dynamically searches a communications band for transmissions of messages having the same nominal communications parameters, including the use of the same spreading code, but having potentially different specific frequencies and code-phases. The receiver samples the communications band at each code-phase of the spreading code over a span of down-converted transmission frequencies. When a message element is detected at a particular code-phase and frequency, it is forwarded to a demodulator that demodulates the message and sends it to its intended destination. This technique allows each transmitter to be independent of the receiver. In a preferred embodiment of this invention, a Fast M-Sequence Transform (a Walsh-Hadamard Transform) is used to determine the power level at multiple code-phases at a given frequency in parallel, thereby substantially reducing the time required to search for transmissions at each discrete code-phase.

The invention relates to a method and apparatus for acquiring a complex spreading code of a direct sequence spread spectrum signal (DSSS) by acquiring a state of a spreading code generator capable of generating the complex spreading code. A sequence of bipolar differential product values, which sign is independent on data transmitted by the DSSS signal, is obtained by combining in-phase and quadrature samples of the DSSS signal for adjacent chip intervals. This sequence is provided to a linear block decoder for obtaining a codeword of a linear block code, which is defined by a structure of the spreading generator and the differential product operation. The codeword is used to compute the state of the spreading code generator.

This invention discloses one method to strengthen picture element area codes, which comprises the following steps: a, decoding the input codes of MPEG-2 input code flow; outputting decoding information besides the video data of YUV form; if each frame of image coding mode, each macro coding mode; then making full use of MPEG-2 decoding to get output information and re-coding the YUV form visual data for AVS data; finally coding, and considering the characteristics of MPEG-2 and AV codes with quality and speed.

The invention relates to a wireless sensor networks data compression method based on self-adaptive optimal zero suppression. Data in the existing wireless sensor network often presents abundant redundant information, which can waste communication bandwidth, increase network delay and node energy consumption. In the invention, a lossless self-adaptive optimal zero suppression algorithm is introduced, i.e. the zero suppression calculation and coding are carried out on a perceptive data sequence with an increasing sequence through self-adaptive searching an optimal digit factor, so the final coding length of the perceptive data sequence is the shortest, the correlation of the data collected by the sensor nodes can be fully excavated and the redundant information can be deleted to the maximaldegree, thus the average energy consumption of the nodes can be reduced and the service life of the sensor networks can be prolonged. The method in the invention can reduce the required data transmission volume in the network, thereby reducing the average energy consumption of the nodes and the network delay.

The invention discloses a digital matching filter for WCDMA (wideband code division multiple access) communication. An A / D (analog to digital) conversion module is used for carrying out sampling quantization on each collected sampling value, a serial / parallel conversion module is used for dividing samplings in former and later n times for a same code sheet to obtain data with an odd power and an even power sequences of a path I and a path Q, a matching filter module is used for carrying out data matching on the data with odd power and the even power sequences of the path I and the path Q through a Golay sequence correlator, the serial / parallel conversion module is used for recovering the data with the odd power and the even power sequences of the path I and the path Q output by the matching filter module into an original data sequences of the path I and the path Q, a quadratic sum calculation module is used for carrying out quadratic sum calculation on the original data sequences of the path I and the path Q, and a relative detection module is used for carrying out peak value detection on a result of the quadratic sum calculation of the original data sequences of the path I and the path Q output by the quadratic sum calculation module to realize synchronization of a main synchronization sequence; and hardware resource is reduced, a data processing speed is improved, a synchronous sequence in time slot synchronization of WCDMA communication system community searching is rapidly captured.

Methods for transposing elements of a sequence according to a rule, wherein the rule is derived from pseudo-noise or pseudo-noise like binary and non-binary sequences are disclosed. Sequences of transposed symbols can be recovered by applying a reversing rule. Sets of orthogonal hopping and transposition rules are created by applying transposition rules upon themselves. Sets of orthogonal hopping and transposition rules are also created from binary and non-binary Gold sequences.

In a real-time mode, a clock signal of a searcher architecture is disabled between synchronization sequence bursts. In a sample storage or asynchronous mode, portions of stored signals do not belong to any hypothesis to be tested (e.g. portions that occur between synchronization signal bursts) are not loaded into the searcher delay chain.

A method for receiving spread spectrum signals and for initial code acquisition from the received signals comprises de-spreading the received signals, based on code phase synchronization, to produce a de-spread signal; and performing a modulation detection based on a change of time-domain characteristic of the de-spread signal.