187results about How to "Reduce sync time" patented technology

A protocol, method, and apparatus for managing network communications which are particularly well suited for ATM communications across a wireless medium. Contiguous time slots within a frame are allocated to each node having traffic to send. Each node is assured a nominal bandwidth, and excess bandwidth is distributed by demand. The allocation of excess bandwidth can be dependent upon the size of the buffer at each node, as well as the time-criticality of each message. Nodes communicate their requests for allocation by appending such control information to the first of their transmitted packets. The allocation, of each node's transmit and receive time slots, is transmitted to all the nodes at the beginning of each frame. Thereafter, each node need not participate on the network until their allocated time periods, thereby allowing portable devices to enter inactive states to conserve power. The network is operated in a connection mode; connections are established in a relatively non-interfering manner by the use of periodically occurring beacons. Inactive, unconnected, nodes need only monitor the network during these beacon periods, further allowing for power conservation.

The invention discloses a carrier synchronization method of a burst direct sequence spread spectrum system, which is mainly used for solving the problems of low carrier bias estimation precision and small carrier bias estimation range in the traditional DSSS (Direct Sequence Spread Spectrum) communication system carrier synchronization technology. The carrier synchronization method comprises the following steps of: firstly, carrying out coarse estimation on carrier frequency offset and phase offset through a pilot frequency assistance-based average periodogram method and an ML (Multi-Lag) phase offset estimation method; secondly, determining a frequency offset fine estimation interval of each iteration during fine estimation; and in the frequency offset fine estimation interval of each iteration, searching by using maximizing despread output information mean square value as a rule to obtain accurate estimation values of carrier frequency offset and phase offset, and realizing carrier synchronization of a DSSS system. The invention can be used for correcting a large carrier offset by using less pilot frequency overhead, realizes effective carrier synchronization, obtains an approximately perfect bit error rate, and is suitable for a burst DSSS communication system.

The invention discloses a time service method using a navigational satellite, which comprises the steps of: starting a time service synchronous operation by a system; firstly acquiring sending time Ti of a navigation message, and synchronizing the current time to hour, minute and second information obtained from the Ti by the system. By adopting the time service method and device, the synchronization time is shortened and the power consumption of a time service receiver is reduced. The invention is suitable for multiple kinds of satellite navigation systems, such as GPS, Big Dipper one-generation navigation satellite, Big Dipper second-generation navigation satellite, GLONASS (Global Navigation Satellite System), GALILEO and other satellite navigation systems. In addition, the invention is also suitable for dual-mode/multi-mode satellite navigation systems and dual-mode/multi-mode hybrid satellite navigation systems.

In accordance with various embodiments of the disclosed subject matter, a method and a system for detecting multiple objects from real-time images are provided. The method comprises: performing, using a CPU host, an image segmentation process to divide real-time input images into a plurality of image partitions; performing, by multiple GPUs, a fast block-wise registration process, a mark setting process, a background generation process, a foreground generation process based on a Hyper-Q computation infrastructure, and a support vector machine classification process; and generating, by the CPU host, visualization classification images.

A method for synchronizing clocks in nodes of a vehicle network of a motor vehicle corrects a time difference between a master clock and a slave clock, taking into account transmission delay for a message between a master node and a slave node. At least for a first synchronization of the master clock to a slave clock after the nodes of the vehicle network are started up, a default transmission delay in the slave node is used to correct the time difference, and/or the slave node sending out a Delay Request message, and recording in the master node the time at which Delay Request message is received and the master node sending the time, as a Delay Response message, back to the slave node. In the slave node, the transmission delay for a message between the master node and the slave node is determined.

Characters of the method are that repeating a PN sequence for once at sending end; when receiving each L pieces of data, receiving end carries out autocorrelation once to find out the position of the first value, which exceeds threshold; before the said position, starting carrying out M+1 times of cross correlation, and carrying out conjugated multiplication for two adjacent values of cross correlation; finally, finding out position of first value, which exceeds threshold, form moduli of M pieces of conjugated multiplications in order to accurate position of time synchronization so as to realize fast time synchronism. The invention reduces complexity of implementation, and raises speed of time synchronism for receiver.

The invention provides a block chain information transmission method and system based on satellite-ground collaboration. The method comprises the following steps that a block chain core node receivesto-be-transmitted information sent by a block chain node, and verifies the to-be-transmitted information; after the verification is passed, the block chain core node sends the to-be-transmitted information to a communication satellite; and the communication satellite receives the to-be-transmitted information and broadcasts the to-be-transmitted information to each block chain node and the block chain core node through a wireless channel, so that each block chain node and the block chain core node carry out corresponding processing on stored block chains according to the to-be-transmitted information. According to the method and the system, the communication satellite broadcasts the information to each block chain node at the same time, so that point-to-point transmission in a P2P broadcasting scheme is avoided, the information transmission efficiency of the block chains is improved, the synchronization time of the nodes of the whole network is shortened, and the transaction efficiencyof a block chain system is improved.

A frame synchronization method of a GPS receiver comprises the following steps: (1) after the GPS receiver is turned on and is fixed firstly, the local clock is adjusted periodically to ensure that the times and variation periods of the local clock and the GPS clock are consistent, the current position of the GPS receiver is recorded; (2) after the channel of the GPS receiver is unlocked and recaptured, the local time and ephemeris are read, the preliminary position of the satellite is calculated according to the ephemeris and the approximate launch time of satellite signals; (3) the uncorrected approximate distance of the GPS receiver and the satellite is calculated according to the recorded initial position of the GPS receiver and the preliminary position of the satellite so as to obtain pseudorange; (4) the local time is corrected according to the time used for executing the step (2) and the step (3) to obtain the satellite launch time of the current teletext; and (5) the frame count, bit count and millisecond count of the current teletext are calculated according to the result of the step (4), and frame synchronization is performed to extract the teletext.

A signal transmission system used on digital multimedia broadcast comprises source adaptive buffer storage for buffer-storing data sent from source and for sending data to channel modulator, channel modulator for carrying out coding-modulation on received data and for sending coding-modulated data out, channel demodulator for carrying out decoding-modulation on received data and information sink buffer storage for buffer-storing received data.

The invention provides a mode for fast synchronization and simple and precise data storage of a block chain system, wherein an account hash is added in a block header data structure of the block chainsystem, which represents a hash summary of a complete account. During the synchronization of block chain system, synchronizing all block headers first, get the ledger hash from the latest block header, then according to the book hash, synchronizing a full account from the network, to reduce the synchronization of block data, on the one hand, the synchronization time and the storage space requirement of the whole node in the block chain system are greatly reduced; on the other hand, the old block data can be deleted at any time during the operation of the node in the block chain system, so asto reduce the storage space requirement in the operation process.

A short synchronization time modem comprising a GPS receiver for receiving a broadcasted signal comprising a high precision clock. When a first short synchronization data modem communicates with a second, a PLL in each data modem synchronizes its own local clock to the same high precision clock derived from the same received broadcasted signal. The modems connect for the first time using one of many clock recovery schemes known to the modem designers. Once they disconnect, the modems keep their clocks synchronized using a local GPS receiver and the received broadcasted signal. This prevents the local clock of the modems from drifting, which significantly reduces the time period the modems need to synchronize the next time they connect.

The invention discloses a time slot synchronization method for resisting sampling clock frequency deviation in a WCDMA (Wideband Code Division Multiple Access) system in the technical field of communication. The time slot synchronization of a downgoing signal in the WCDMA system is completed by steps of: carrying out high-rate oversampling on an input signal, wherein the sampling rate is chippingrate of 6-10 multiples; dividing the input signal into multiple paths of signal searching time slot boundaries after downsampling; and finally finding out a correct time slot boundary point with a comparison and combination method. The invention not only can eliminate the influence of the sampling clock frequency deviation to the time slot synchronization in the initial synchronization period, but also needs no extra sampling clock synchronization device compared with the prior art; and moreover, the system has the advantages of lower complexity and less resource consumption, which ensures the synchronization time to be greatly shortened.

The invention provides a file synchronization method, a server and a terminal. The method comprises the following steps of receiving a file synchronization request sent by the terminal; responding to the file synchronization request, and checking first recording data from each data edition of files stored in the server. The first recording data include operation records generated after a preset edition of the files recently makes the files synchronized on the terminal. The method further comprises the steps of sending the first recording data to the terminal so that the terminal acquires corresponding operations which should be executed by the terminal according to the first recording data and second recording data on the terminal. The second recording data include records of operations performed by the terminal on the files after the recent file synchronization. The file synchronization time can be shortened. The network resource consumption can be reduced. The synchronization efficiency can be further improved.

The invention is a 3D surface synchronizer, belonging to automobile driving device field, including: two-stage gear, inner conical ring, outer conical ring, medium ring, synchronizer spring, tooth case, gear hub, slide block, one-stage gear, first groove, slide block groove, and second groove, where inner conical ring, outer conical ring and medium ring are set in sequence from inside to outside to compose a friction ring on the gear, the inner conical ring is covered on the conical surface of the gear, the medium ring covered on the inner conical ring and the outer conical covered the medium ring, the medium ring is connected with the two-stage gear and one-stage gear by the grooves on the stage tooth, the slide groove is on the inner wall of the tooth case, the whole slide block is inserted in the groove of the gear hub, two synchronizer springs tightly adhere to two sides of the gear hub, respectively, and the outer conical ring is set with groove at the big end. It largely enhances synchronous torque, thus shortens synchronous time and widens the working range of the synchronizer, etc.

The invention discloses a low consumption control method for micro power wireless communication, a terminal and a system. The method comprises the following steps: receiving a data code broadcasted by a central controller, wherein the data code comprises a local time of the central controller, transmitting power of the central controller, a synchronization word, a broadcast time interval T, a communication state bit and a check code; updating the local time of terminal according to the local time of the central controller, and adjusting the transmitting power of the terminal according to the transmitting power of the central controller; and setting a time interval of waking from a shutdown state to establishing a communication connection with the central controller of a micro power wireless module as nT-tt-tp, and setting the micro power wireless module as the shutdown state, wherein tt refers to a preset time margin value, and tp refers to a time from sending a response message to the central controller to receiving a confirmation response message replied by the central controller.

The invention discloses a data synchronization method and device, and relates to the technical field of computers. One specific embodiment of the method comprises the steps of monitoring a first database, so as to obtain an updated log file from the first database when a log in the first database changes; analyzing the log file to obtain incremental data, and writing the incremental data into a message queue corresponding to a table name in the incremental data according to the table name in the incremental data; and writing the incremental data in the message queue into a second database through a queue consumption thread corresponding to the message queue. According to the embodiment, the whole data synchronization method has a clear architecture, and the table-level concurrent processing mode is adopted in the parallel implementation stage in the data synchronization process, so that the overall concurrency is greatly improved, the data synchronization efficiency is effectively improved, the data synchronization time is shortened, and meanwhile, the data synchronization consistency is ensured.

It is provided a control device for a vehicular power transmitting apparatus provided with a transmission disposed in a power transmitting path between an electric motor and drive wheels, the control device switching a synchronizing control method of the transmission in a kickdown shifting performed in the transmission to either one of a rotation-synchronization control by a hydraulic pressure control of the transmission and a rotation-synchronization control by the electric motor, depending on an input torque applied to the transmission at the beginning of the shifting.

The invention relates to an electromechanical coupling transmission device synchronization control device based on a manual transmission, which comprises a motor, a fixed axis gearbox, a gear shift transmission mechanism, a gear selection transmission mechanism, an operating handle, a shift force sensor, a gear shift position sensor, a gear selection position sensor and a transmission control unit, wherein the transmission control unit is connected with the motor, the shift force sensor, the gear shift position sensor and the gear selection position sensor respectively; the fixed axis gearbox is connected with the motor, the gear shift transmission mechanism and the gear selection transmission mechanism respectively; and the gear shift transmission mechanism is connected with the shift force sensor, the gear shift position sensor and the operating handle respectively. The invention also relates to an electromechanical coupling transmission device synchronization control method based on the manual transmission, which comprises the following steps that: 1) the gear shift position sensor and the gear selection position sensor detect an initial gear of the vehicle when the vehicle is in a running state, and the like. Compared with the prior art, the invention has the advantages of wide application range, convenience of operation and the like.

The invention discloses an OFDM (Orthogonal Frequency Division Multiplexing) symbol timing and frequency offset estimation method based on a particle swarm optimization (PSO) algorithm. The OFDM symbol timing and frequency offset estimation method comprises a scheme designing process and a scheme implementation process, wherein the scheme designing process comprises a step of establishing a corresponding relationship between an OFDM symbol timing and frequency offset combined estimation parameter and each parameter of an PSO algorithm; and the scheme implementation process comprises a step of finishing a task of searching an OFDM symbol timing and frequency offset combined optimal position. The OFDM symbol timing and frequency offset estimation method can be used for realizing the accurate estimation on symbol timing and frequency offset, effectively overcoming the influence of the integer frequency offset in a conventional OFDM symbol synchronization algorithm to symbol timing estimation and realizing the purpose of accurately estimating the OFDM symbol timing and the frequency offset. The computation complexity can be reduced and the OFDM symbol synchronization time is shortened on the precision of not reducing the performance; and the OFDM symbol timing and frequency offset estimation method is a simple and practical method for realizing the OFDM symbol timing and the frequency synchronization in a packet bursting wireless transmission system.

An apparatus and a method for acquiring initial synchronization in a wireless communication system based on Orthogonal Frequency Division Multiplexing (OFDM) are provided. The apparatus includes a frame synchronizer for acquiring frame synchronization using a preamble signal, a first offset determiner for determining a first time offset and a first frequency offset based on the frame synchronization, a preamble identifier estimator for estimating a preamble identifier in a receive signal interpolated with the first time offset and the first frequency offset, and a second offset determiner for generating a first preamble signal and a first pilot signal corresponding to the preamble identifier, for derandomizing a preamble signal and a pilot signal, and for determining a second time offset and a second frequency offset. Thus, the initial synchronization acquisition time in a low Signal-to-Noise Ratio (SNR) environment can be reduced.

The invention relates to a cluster-based distributed antenna time frequency synchronizing method in wireless communication, and belongs to the technical field of wireless communication. The method comprises the following steps of: dividing mass distributed antennas into clusters, selecting cluster representative antennas, and performing distributed bidirectional coordinated synchronization on the cluster representative antennas; and then, initiating intra-cluster distributed bidirectional coordinated synchronization by the cluster representative antennas so as to finally realize time frequency synchronization of all distributed antennas in a system. The method has the following advantages that: through cluster division, a plurality of clusters are simultaneously synchronized, the total synchronization time is reduced and the synchronization speed is quickened; the synchronization between the cluster representative antennas is performed first and then the intra-cluster distributed bidirectional coordinated synchronization is performed so as to obtain higher synchronization precision and meet the requirement of a distributed wireless communication system for synchronization precision; and the synchronization between the distributed antennas is finished in advance so as to avoid multiple times of synchronization between a terminal user and a plurality of distributed antennas. The method reduces the system resource overhead of the terminal user, and improves the communication reliability.

The invention relates to an online updating device and an online updating method for a virtual server cluster. The online updating device comprises a first synchronization module, a second synchronization module and a first control module, wherein the first synchronization module is used for controlling one server in the virtual server cluster to realize synchronization of an upgrade file; the second synchronization module is used for synchronizing the upgrade file to other servers in the virtual server cluster; the first control module is used for modifying a health examination file in the server where the second synchronization module is located into an abnormal state when the server where the second synchronization module is located realizes synchronization of the upgrade file; the server where the second synchronization module is located is used for recovering the health examination file in the server where the second synchronization module is located into a normal state while the synchronization of the upgrade file is finished. Due to the adoption of the scheme of the invention, update service is provided for a user terminal uninterruptedly while the server automatically updates the upgrade file, so that not only is the efficiency of updating the upgrade file by the virtual server cluster promoted, but also favorable user experience is brought to a user.

The invention discloses a signal synchronization method of a satellite-borne GNSS receiver based on orbital dynamics assistance. The signal synchronization method comprises the steps that (1) input data preparation for the GNSS receiver is performed; (2) the orbital dynamics recursion of a motion state of the GNSS receivers is performed; (3) an estimated value of the sending time of all signals arriving at the GNSS receiver at time t1 and the position and velocity of a corresponding GNSS satellite in an ECI system are calculated; (4) auxiliary information calculation is performed; and (5) signal synchronization assistance is performed. The signal synchronization method can greatly reduce the time required for GNSS signal synchronization, and then improves the overall navigation performanceof the satellite-borne GNSS receiver, the algorithm is simple and reliable, and the signal synchronization method is suitable for the satellite-borne GNSS receiver.

The invention discloses a hybrid electric vehicle power transmission system and a power transmission method thereof. The system comprises an engine, a gearbox, a torsion damper, a motor output shaft and a motor, the gearbox comprises an input shaft and an output shaft, and the input shaft is fixedly connected with the driven end of the torsion damper; the input shaft is sleeved with a first driving gear and a second driving gear in a spaced mode. The first driving gear and the second driving gear are each provided with a joint gear ring, the first bilateral synchronizer is located between thefirst driving gear and the second driving gear and connected with the input shaft, and the input shaft is connected with or separated from the first driving gear and the second driving gear through left-right movement of a joint sleeve of the first bilateral synchronizer. The problem of power interruption in the gear shifting process of the gearbox is solved, and meanwhile four-gear engine driving, three-gear pure electric driving, two-mode parking power generation and engine starting are achieved.

At sending end, a PN sequence is repeated for multiple times continuously. The training sequence is constituted after positive and negative polarities of front some segments of PN sequence are determined by barker code. Emission data are constituted by weighted addition in point to point between the said training sequence and OFDM original data. At receiving end, sectional correlation calculation with barker code as weight value is carried out so as to obtain objective function value utilized to evaluate point of time synchronization. The point making the objective function value exceed prearranged threshold is a point of time synchronization. The method possesses advantages of fast synchronization speed and simple implementation, suitable for synchronization of OFDM system under packet transmission.