173 results about "Slot synchronization" patented technology

In a cellular communications system having a centralized radio processing portion (a base station hotel) in communication with a plurality of remote air interface radio portions (or radio heads) over a transport medium, the centralized radio processing portion compensates for a fixed delay associated with the transport medium coupling the centralized radio processing portion and one of the remote air interface radio portions when evaluating a time period corresponding to a variable delay between transmission by a mobile in communication with the one of air interface radio portions and receipt of the transmission by the centralized radio processing portion. The variable delay may relate to time out periods or time slot synchronization.

In a cellular communications system having a centralized radio processing portion (a base station hotel) in communication with a plurality of remote air interface radio portions (or radio heads) over a transport medium, the centralized radio processing portion compensates for a fixed delay associated with the transport medium coupling the centralized radio processing portion and one of the remote air interface radio portions when evaluating a time period corresponding to a variable delay between transmission by a mobile in communication with the one of air interface radio portions and receipt of the transmission by the centralized radio processing portion. The variable delay may relate to time out periods or time slot synchronization.

The invention discloses a method for realizing base station synchronization, which includes the following steps: a second base station defines a first base station according to indication information sent by other base stations; the second base station searches the position of a descending pilot frequency time slot (DwPTS) of the first base station and adjusts the position of the DwPTS according to the position of the searched DwPTS; the second base station reads a system frame number (SFN) from the broadcasting information of the first base station and updates the SFN to be the read SFN. In the invention, the second base station realizes synchronization among different base stations through building the time slot synchronization and frame synchronization with the first base station. Not every base station is needed to be provided with a GPS receiver, therefore, the system cost is greatly reduced. In addition, the realization of the invention can completely break away GPS, therefore, the synchronization among all the base stations can be still ensured when the GPS fails. The invention also discloses a device for realizing the synchronization of the base station and a relevant base station.

A light wavelength exchange method based on a network wide synchronous, time slot characterizes in applying light time slot as the service transfer structure smallest exchange connection unit, all nodal points carry out light channel cross connection dispatch according to each related I / O port connection allocation table in an unified time slot synchronization, edge user network interfaces transfer services, based on related service time slot image tables, solving the problem of cross connection and route based on wavelength.

The invention relates to time slot synchronous system and method of GEO (geographic) satellite mobile communication based on 3G under a high dynamic environment. The time slot synchronous system comprises an antenna, a radio frequency circuit module, an A / D (Analogue to Digital) conversion module, an orthogonal down-conversion module, a low pass filter module and a numerical controlled oscillator module. The time slot synchronous system is characterized by comprising a matched filtering module, an FFT (Fast Fourier Transform) module and a carrier tracking module, wherein the key folded matched filtering module in the matched filtering module is designed based on equal capture velocity to save the hardware resources greatly. The FFT module and the carrier tracking module are combined so that the capture velocity to the carrier frequency is greater and more accurate. At the same time, by adopting the invention, time slot synchronization to a GEO satellite down-link channel can be realized under the high dynamic environment that Doppler frequency shift is 40KHz.

Provided is a wireless relay system that improves system throughput between terminal stations and flexibly makes system throughput variable with respect to short-term traffic fluctuations. In the wireless relay system, a plurality of relay stations relay communication between two terminal stations that perform random access. The terminal stations and the relay stations include a slot synchronization unit, a time synchronization unit, and a transmission unit. The slot synchronization unit synchronizes slot timing of a time slot indicating a unit time. The time synchronization unit performs time synchronization for synchronization of the slot timing. The transmission unit transmits a transmission packet to a wireless line in synchronization with the slot timing. A transmission right is allocated for at least one time slot to each of a plurality of groups which are configured so that a group of a terminal station or a relay station and a group of an adjacent terminal station or an adjacent relay station are different from each other. The transmission unit transmits the transmission packet to the wireless line only in a time slot in which the transmission right is allocated to the group to which the terminal station or the relay station belongs.

A method of cell search in a wireless communication systems having a plurality of base stations and a mobile station, each of the plurality of base stations serving a separate cell within a service area and transmitting a common primary synchronization code (PSC) in a primary synchronization channel within a slot of a radio frame, the method including the steps of: (a) scanning (72) through radio channels in scanning increments corresponding to a standard channel raster; (b) estimating (98) the PSC signal-to-noise ratio of each radio channel; (c) if a PSC signal-to-noise ratio is above a first predetermined threshold level (100), completing a cell search procedure including slot synchronization, frame synchronization and scrambling code detection steps for that radio channel; (d) if the cell search procedure is successfully completed (112) for the radio channel in step (c), increasing the scanning increments to the broadcast frequency separation between cells; (e) when all radio channels are scanned in step (d), sorting (74) the scanned radio channels in descending order by PSC signal-to-noise ratio; and (f) performing (76) the cell search procedure on each sorted radio channel in descending order.

A method of performing a continuous cell search for new cells in a wireless communication systems having a plurality of base stations and a mobile station, the method including the steps of: (a) using (1) a primary synchronization code to acquire slot synchronization for identified cells; (b) using (2) a secondary synchronization code to find frame synchronization and identify a code group of the identified cells; (c) determining (3) a primary scrambling code used by the identified cells; and (d) rejecting (4) cells corresponding to previously identified primary scrambling codes from post-processing, wherein the method further includes the steps of: (e) correlating slot timings identified in step (a) with frame timings corresponding to primary scrambling codes identified in previous runs of steps (b) and (c); and (f) rejecting slot timings identified in step (a) from further processing in steps (b) and (c) when correlation is detected.

The invention provides a wireless sensor component and a TDMA self-organized network implementation method based on the wireless sensor component, wherein each node of a network is provided with one wireless sensor component. The TDMA self-organized network implementation method comprises the following steps: step one, time slots of a TDMA self-organized network are determined, one time slot is set for each wireless sensor component, and each time slot comprises three beats; step two, a TDMA networking initiating node is determined; step three, time slot synchronization is conducted on the TDMA self-organized network. According to the wireless sensor component and the TDMA self-organized network implementation method based on the wireless sensor component, a mutual synchronization method is adopted, time slot synchronization starts from an initiating node of frame synchronization, frame initiating moments of all the nodes are aligned with the initiating node till the frame initiating moments of all reachable nodes in the network are aligned with an initiator, and therefore the aligning process is completed. Time slot synchronization of the organized network progresses at a high speed which can reach five microseconds; besides, the mutual synchronization method is adopted, so that clocks of all the nodes are controlled mutually, it is avoided that a certain node is depended on, invulnerability is high, and the wireless sensor component can adapt for dynamically-changing network topology.

The invention provides a mobile communication terminal that allows the time for recognizing the scrambling code to be shortened. The mobile communication terminal predicts the scrambling code to be searched at the next time by collating the previous result of GPS information process and the stored content of a position information database in a control part, if establishment of slot synchronization is completed employing a slot synchronization part. The control part acquires the information required for inverse spreading of the predicted scrambling code from a memory, and generates a code for inverse spreading. A predicted scrambling code recognition part inputs the code for inverse spreading shifted in a unit of slot from the control part, and attempts inverse spreading. The control part suspends a normal three-stage cell search that is performed in parallel with the cell search of the invention, if prediction from the position information is determined to be correct in the predicted scrambling code recognition part.

The present invention discloses a frequency hopping communication method for digital centreless communication systems, which includes procedures below: Service frequency points are divided into one or a plurality of frequency hopping sequence sets. A calling broadcasting station detects state of each service frequency point and selects a frequency hopping sequence set of higher quality. After acquisition of time slot synchronization for the calling broadcasting station and a designated service frequency point, the calling broadcasting station initiates a call request to a called broadcasting station and transfers the call request to the designated service frequency point and the time slot. After receiving the call request from the calling broadcasting station, the called broadcasting station transfers to the service frequency point and the time slot designated by the call request of the calling broadcasting station. The calling broadcasting station communicates with the called broadcasting station on the designated frequency point and the time slot. Different call frames circularly use each service frequency point in a selected frequency hopping sequence set through frequency hopping until communication is finished. The method reduces impact of selective frequency attenuation on normal communication of broadcasting stations and improves communication efficiency.

To execute the cell-search procedure in a cellular communication system (such as a system based upon the 3GPP TDD standard), there are available identification codes for the second step (slot synchronization) and for the third step (identification of the scrambling codes). The identification codes are identified by a process of correlation with the received signal and are used for obtaining from a correspondence table the parameters for the execution of the second step (CD) or of the third step (SCR). The correspondence table is stored in a reduced form by the identification, according to rules of symmetry and redundancy, of subtables designed to generate the entire table by appropriate combination operations. The search procedure in the correspondence table thus reduced is conveniently modified by the introduction of the combination operations. A preferential application is in mobile communication systems based upon standards such as UMTS, CDMA2000, IS95 or WBCDMA.

A Universal Mobile Telephone System (UMTS) receiver performs slot synchronization using a received primary synchronization channel (PSCH) (305). Subsequent to completion of slot synchronization, the UMTS receiver performs frame synchronization using a received secondary synchronization channel (SSCH) (320) in such a way that the UMTS receiver uses the received primary synchronization channel (PSCH) to adjust for the presence of frequency offset (325, 330, 335).

Operation of partial correlation or total correlation is carried out between first sync code and receiving signal. Operation of difference detection is carried out for the result of correlation operation. Based on result of partial correlation operation or result of difference detection, determination of time slot synchronization of first step for sub zone searching is carried out in order to raise capability of anti initial frequency error in sub zone searching. Using the said result of difference detection estimates frequency deviation between carrier signal generated by local oscillator and carrier signal in received signal, and controls corresponding frequency in order to reduce frequency deviation. Based on estimated frequency deviation, Operations of correlation for second and third steps in zone searching are selected. Thus, false detection rate in the said second and third steps are reduced, and receptivity of broadcast channel is raised after zone searching.

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.

A method of performing a continuous cell search for new cells in a wireless communication systems having a plurality of base stations and a mobile station, the method including the steps of: (a) using (1) a primary synchronization code to acquire slot synchronization for identified cells; (b) using (2) a secondary synchronization code to find frame synchronization and identify a code group of the identified cells; (c) determining (3) a primary scrambling code used by the identified cells; and (d) rejecting (4) cells corresponding to previously identified primary scrambling codes from post-processing, wherein the method further includes the steps of: (e) correlating slot timings identified in step (a) with frame timings corresponding to primary scrambling codes identified in previous runs of steps (b) and (c); and (f) rejecting slot timings identified in step (a) from further processing in steps (b) and (c) when correlation is detected.

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.

A mobile communication system and cell searching method of the mobile communication network is provided for simplifying a synchronization process required for selecting a target cell. The cell searching method for a mobile communication system includes transmitting, at a base station, a first synchronization signal of a first slot of a frame of a first channel at a higher transmission power than a transmission power of a remainder of the frame of the first channel, acquiring, at a mobile station, a slot synchronization using the first synchronization signal, and acquiring, at the mobile station, a frame synchronization using a second synchronization signal of a second channel, wherein the second synchronization signal corresponds to the first synchronization signal.

The invention discloses a method for establishing communication links between master-and-slave satellites, wherein the master-and-slave satellites include one master satellite and at least one slave satellite. The method concretely includes the steps that a channel between the master satellite and each slave satellite is divided into a control channel and a communication channel; the master satellite and each slave satellite respectively establish a system structure of itself; the links are established between the master satellite and the slave satellites, and the communication process starts; the master satellite sends control frames corresponding to all the satellites in a control time slot, each slave satellite captures the synchronous head of the control frames, a local clock of each slave satellite is calibrated by referring to a local clock of the master satellite, and time slot synchronization is completed; after the time synchronization, each slave satellite sends a communication frame in a communication time slot, link establishment is completed after the master satellite captures the communication frames sent by the slave satellites, a network is adjusted to the communication channel, and data communication starts. According to the technical scheme, the method for establishing the communication links has the advantages of being capable of centralized management, easy to maintain, high in safety, short in delay time and low in transmission bit error rate.

Synchronization within a common communication channel having designated transmission time slots for various devices of a computer network is maintained by allowing transmissions within the channel outside of a network device's designated time slot when a clear channel assessment indicates that a previous time slot is not being utilized by its associated device and / or upon receipt of an indication of the end of a transmission of another device in the network. The clear channel assessment preferably takes into account the device's designated transmission time slot within the communication channel with respect to those of other network devices and may be a time period that is the product of a predetermined clear channel waiting time and a numerical representation of the device's designated transmission time slot within the communication channel with respect to those of other network devices. The clear channel waiting time itself may be specified by a network master device as part of a network connection process. The network device may be configured to construct one or more packets for transmission within the network in advance of its designated time slot to accommodate these early transmissions.

The application relates to a master-slave TDMA time slot synchronization calibration method and a device. The method comprises the following steps: at least one slave machine receives a synchronization frame from a master machine, wherein the synchronization frame includes a first count value of a timing counter in the master machine; the at least one slave machine analyzes the synchronization frame to get the first count value; and for each slave machine, the TDMA time slot of the slave machine is adjusted according to the first count value and a second count value of a timing counter in the slave machine in order to synchronize the TDMA time slot of the slave machine with the TDMA time slot of the master machine. Synchronization is carried out directly using the clock sources of the master machine and the slave machines, without the need to add an RTC clock source and a GPS module. The accuracy is improved while the cost is reduced.

The invention discloses real-time position communication equipment and a time slot synchronization method. The real-time position communication equipment comprises a plurality of nodes that require time slot synchronization, a LoRa gateway, a server and a client; the nodes are used for receiving own geographical position information sent by a GPS satellite, and sending the geographical position information to the LoRa gateway; the LoRa gateway has a fixed ip, and is used for receiving position information of the nodes and sending the position information to the server; and after the LoRa gateway receives the geographical position information of a node i, the geographical position information is forwarded to the server through the Internet or the mobile network, and the client matched withthe node i can access the server through the Internet or the mobile network, and check the geographical position of the node i.

The invention relates to a synthesis and open loop synchronization method of a photon detection array signal, and belongs to the field of deep-space laser communications. The method comprises the following steps: firstly, detecting a PPM (Pulse Position Modulation) signal after channel transmission by N photon detectors; secondly, measuring the arrival time of each photon of each branch signal and finishing the combination of each branch signal; thirdly, performing timing error estimation, and performing PPM time slot data recovery on a composite signal according to estimated initial phase deviation and frequency deviation; and finally, demodulating and outputting. The synthesis and open loop synchronization method of the photon detection array signal provided by the invention realizes PPM time slot synchronization by measuring the arrival time of the photons so as to further realize demodulation; an open loop synchronization mode is adopted to replace a closed loop clock synchronization mode of a phase-locked loop and an early-late gate to realize time slot synchronization; and an array signal synthesis method is simple, easy to implement, low in bit error rate and high in accuracy.

A DSRC communication technology that prevents unique word detection errors even when the frame changes in data reception and the timing of the unique word detection window and the timing of the received data do not match, and that adjusts the data transmission timing in a flexible fashion when the slot timing deviates from the frame timing. In this technology, bit counter 111 generates the frame timing from the frame synchronization signal, and bit counter 112 generates the sot timing in response to the slot synchronization signal. The unique word detection window is generated from the frame timing and the received data operation timing and the data reception timing are generated from the slot timing. In addition, the data transmission timing and the transmission data operation timing are generated based on one of the frame timing and the slot timing chosen in selector 123.

A cell search system for a mobile station in a time division duplex system includes: a primary synchronization code search module for searching primary synchronization codes and comparing frame values of the primary synchronization codes to determine a position of the maximum value; a correlation module for estimating a phase value and acquiring a first correlation value; a secondary synchronization code search module for generating determinative variables and storing them based on the position of the maximum value; a comparison and decision module for detecting a maximum value of the determinative variables, comparing it with the values stored in the secondary synchronization code search module to count matching values, and comparing the count value with a system value to decide whether slot synchronization and group acquisition is successful; and a base station determination module for determining a second correlation value between midamble codes and the received signals, and selecting a maximum value of it to determine a base station.

In a first step, slot synchronization may be obtained by setting in correlation the received signal with a primary sequence, which represents the primary channel, and storing the received signal. During a second step, the correlator may be re-used for correlating the received signal with a secondary sequence corresponding to the secondary synchronization codes. The correlator may include a first filter and a second filter connected in series, which receive a first secondary sequence and a second secondary sequence, which may include Golay sequences. Architectures of parallel and serial types, as well as architectures designed for reusing further circuit parts are also disclosed. The invention is particularly applicable in mobile communication systems based upon standards such as UMTS, CDMA2000, IS95, and WBCDMA.

A wireless system broadcasts data in frames, each frame having F slots. Output from a matched filter is used to combine K slots to generate profile data, where K is less than F. N peak values respectively from n peak positions are selected from the profile data, where n is greater than one. A correlator is employed, together with the n peak positions and S slots subsequent the K slots, to generate n×S correlation values. Respective combination values for the n peak positions are generated by coherently combining the correlation values, and combining the coherent combination results with the non-coherent n peak values. The combination values are respectively used to generate SNR values for each of the n peak positions. The peak position having the best respective SNR value is then selected as a slot synchronization position.

This invention provides a search method and a system for local areas in a mobile system, in which, the method includes: applying for a time slot synchronization resource to match with related parameters, generating a result after the synchronous operation and sequencing the peak values of the synchronization, taking out multiple peak values and their position offsets and releasing the time slot synchronization resource, applying for a synchronization resource of two frames or an identification resource of a scrambling code set, setting related parameters, searching the multiple peak values and their offsets of the time slot synchronization, in which, the search result is the frame synchronization point and scrambling code set and then releasing related resource after the search, and applying for an identifying resource of scrambling codes setting parameters in the last step to search for the scrambling code and releasing the resource after the search so as to realize operations of time slot synchronization, frame synchronization, identification of scrambling code sets and identification of scrambling codes simultaneously.