54 results about "FCCH" patented technology

Co-channel interference in a wireless network is identified and quantified. Rather that using color code identification, a more reliable identification property of each co-channel component of the received composite signal is used, namely, the time of arrival of a known part of a signal. Detection and timing measurement is performed even in presence of stronger signals by focusing selectively on bursts having fixed contents (e.g., the FCCH burst used in GSM for frequency correction). The repetitive measurements of the time-of-arrival of each of the interfering components of the signal during a drive test enables determination of the geographical location of the interfering co-channel base stations.

The invention relates to a system for realizing microcellular base station synchronization, which is used for the synchronization of GSM; the system comprises: BTS, BSC and Pico; wherein the master-slave synchronization method is adopted between BTSs for realizing synchronization; the hollow port Um of the BTS is adopted for Pico to realize the synchronization between Pico, i.e. the receiving channel of the Um port is used for terminal operation in synchronous receiving state to receive and search the broadcast signal channel BCH frequency points of BTS and then analyze frequency correction signal channel FCCH message so as to obtain BCH carrier timing message, according to timing message calculation and correcting the frequency deviation of local reference clock, the synchronization between Pico is realized. The invention utilizes terminal chipset to make the Pico be operated at two states of either terminal frequency band or base station frequency band, therefore no other base station functions are affected when realizing the synchronization of Pico, thereby enhancing systematic integration degree effectively and reducing systematic manufacture and maintenance cost.

One illustrative method of scanning a radio frequency (RF) band (e.g. 850 MHz band) for valid RF carrier signals of a wireless communication network (e.g. a GSM network) includes the steps of monitoring an RF channel to receive a candidate RF carrier signal; identifying whether the candidate RF carrier signal is a valid RF carrier signal of the wireless communication network by estimating a bandwidth of the candidate RF carrier signal and, if the estimated bandwidth is different from a predetermined bandwidth associated with valid RF carrier signals of the wireless communication network, identifying that the candidate RF signal is not a valid RF carrier signal of the wireless communication network; and repeating the acts of monitoring and identifying for a next RF channel of a plurality of RF channels associated with the wireless communication network. Preferably, the RF bandwidth estimation is performed together with a system signal detection process (e.g. FCCH detection). Advantageously, the time required to scan the RF band is reduced.

A radio receiver for a digital cellular system or the like which transmits or receives, for example, voice signals by coding them, and easily and reliably detects a synchronizing signal. A synchronizing signal FCCH is detected by converting a base band converted transmitted signal with an analog-to-digital convertor circuit 17, and then by detecting a correlation value with a predetermined reference signal.

A terminal obtains a monitored set containing GSM neighbor cells and / or UMTS neighbor cells. The terminal operates in a compressed mode and obtains from a UMTS network at least two transmission gap pattern sequences for different measurement purposes, e.g., for ''GSM carrier RSSI measurements'' (GAP1), ''GSM initial BSIC identification'' (GAP2), and ''GSM BSIC re-confirmation'' (GAP3). The terminal makes RSSI measurements for the GSM cells using multiple transmission gap pattern sequences, e.g., using GAP1, GAP2 and GAP3. The terminal identifies the BSIC for at least one GSM cell by (1) detecting the tone on the FCCH using multiple transmission gap pattern sequences, e.g., using GAP2 and GAP3, and (2) decoding the SCH using multiple transmission gap pattern sequences, e.g., using GAP2 and GAP3. The use of multiple transmission gap pattern sequences for RSSI measurement and BSIC identification allows the terminal to complete the cell measurements and send a report sooner, which may improve performance.

The invention discloses an automatic frequency correction method which comprises the following steps: S1. carrying out down-conversion decimation filtration on a received and sampled digital signal of with the frequency point is 15.36 MHz and the data rate is 61.44 MHz to obtain a 269.473K GSM (Global System for Mobile Communication) signal; S2 carrying out FCCH (frequency correction channel) detection on the GSM signal to acquire an FCCH signal; S3. fitting FCCH data into a linear slope, and demodulating to obtain an output slope; S4. comparing the output slope with the ideal slope to calculate a slope deviation value so as to correspondingly obtain a frequency deviation value; acquiring input data of a synchronous control circuit according to the slope deviation value through a look-up table, and allocating the input data to the synchronous control circuit; and S5. generating an output voltage by the synchronous control circuit according to the input data to control the crystal oscillator clock pulse (CP), thereby implementing the frequency correction. The invention also discloses an automatic frequency correction system.

The invention relates to the field of communication and discloses a GSM neighbor cell searching method for a dual-module terminal and the dual-module terminal. In the invention, the dual-module terminal of a time division synchronous code division multiple access (TD-SCDMA) mode opens a GSM neighbor cell searching function when the predetermined conditions are met, which means receiving GSM frames continuously in a predetermined frame number and pausing the receiving of TD-SCDMA sub-frames until a frequency correction channel (FCCH) of the GSM is detected; and computing the position of a synchronous channel synchronization channel (SCH) signal in the next frame according to the position of the FCCH signal in the GSM frame, receiving the SCH signal and completing the GSM neighbor cell searching. In the invention, under the condition of guaranteeing small influences on the TD-SCDMA service performance, the TD-SCDMA and GSM radio frequency (RF) receiving is completed by an RF chip, so that a great amount of cost is saved, and power consumption is low.

Apparatus, and an associated method, for facilitating synchronization of a mobile station with a radio network in a GSM / EDGE-compatible, cellular communication system. The FCCH is monitored to obtain positional and frequency offset information. Once obtained, the information is used to obtain SCH burst information broadcast upon an SCH. Monitoring of the FCCH continues while the SCH burst information is detected and decoded. If additional FCCH control information is detected that has an associated quality metric value that is better than the quality metric value associated with earlier FCCH, control information, the newly-received information is used to detect the SCH burst information, absent successful decoding of the SCH burst information.

A timing method for search for GSM frequency correction channels from CDMA2000 system includes: setting a search window in every CDMA2000 service frame to search for small community FCCH adjacent to GSM, if it is successful, the search is finished, if not, the search is restarted. When width of search window d is the same, the needed numbers of the search windows are the least, influence to system performance is the smallest and needed search time is the shortest by this inverted timing method.

A code division multiple access (CDMA) receiver can detect the presence of a GSM tone-based signal by programming the digital filter's tap weights to correlate with a GSM FCCH signal. If the correlation between the values of the tap weights and a received signal satisfies a threshold, the receiver produces an indication that a GSM signal is present. Post-processing can be performed on the output of the digital filter to improve signal detection based on the determination of the correlation of the received signal with the digital filter, the determination of the corresponding power value, the determination of the signal strength; and the estimation of the frequency offset.

The present invention is directed toward a system and method for identifying co-channel interference in a radio network. In an exemplary method according to the present invention, a first stream of transmission data having a first received signal frequency at a first reception location for a first period of time is received. Further, the first signal frequency of the first stream of transmission data is identified. Then the transmission data is correlated against a signal template to identify a first FCCH burst frame. Then, first FCCH time data corresponding to the first FCCH burst frame is identified and the signal frequency of the first stream of transmission data and the first FCCH time data is compared to a reference file to determine one or more probable transmission cells.

The invention discloses a method for searching a GSM (Global System for Mobile Communications) adjacent zone by a dual-mode terminal and a dual-mode terminal, belonging to the field of communications. The method comprises the following steps of: receiving an FCCH (Frequency Correction Channel) signal of GSM by using an idle time slot of a TD-SCDMA (Time Division-Synchronization Code Division Multiple Access) subframe, calculating the position of an SCH (Synchronization Channel) signal sent by a network side for the second time in the TD-SCDMA subframe after the FCCH signal is received according to a possible frame number difference N between SCH signals sent in adjacent two times by the network side, and receiving by using the idle time slot of the TD-SCDMA subframe. The time slot resource is fully utilized under the premise of ensuring the functions of TD-SCDMA service. Because one RF (Radio Frequency) chip is used for receiving TD-SCDMA and GSM RF in time division, the mutual interference between two RF is avoided, and moreover, the quantity of used chips can be greatly reduced. A significant cost is saved, and power consumption is lower.

The invention discloses time slot synchronizing and time slot power detecting methods applied to a global system for mobile communication (GSM). The time slot synchronizing method comprises the following steps of: performing sampling rate conversion on the base band data I and Q of a broadcast channel (BCH); extracting the base band data IF and QF of a frequency correction channel (FCCH), capturing a frequency burst (FB) and outputting a time slot rough synchronizing pulse signal; and extracting the base band data IS and QS of a synchronization channel (SCH), capturing a synchronization burst (SB) and outputting a time slot precise synchronizing pulse signal. The time slot power detecting method comprises the steps of the time slot synchronizing method and the step of calculating the time slot power of a GSM signal according to the time slot precise synchronizing pulse signal. The invention also provides time slot synchronizing and time slot power detecting systems applied to the GSM. By the technology, the time slot of the GSM signal of a repeater can be precisely synchronized, and the time slot power can be accurately detected at the same time, so that synchronization reference is provided for the time slot turn-off of the power amplifier of a base station.

A delta-phase detection method for real-time identifying a burst sequence in a received signal. The delta-phase detection method calculates phase differences between every two consecutive samples of the received signal, and counts the number of successive phase differences that are within a predetermined allowable detecting range. The end of the burst sequence is detected if the counting number is within a valid counting range. The valid counting range is determined according to an expected duration of the burst sequence. The frequency of the burst sequence can be calculated by a simple linear equation. A delta-phase detection system is also provided in the present invention, comprising a band pass filter, a delta-phase calculator, a low pass filter, and a flat line detector. The delta-phase detection system can be easily implemented in a digital signal processor of a mobile station to identify the FCCH burst sequence and compute the burst frequency.

The invention discloses a mobile terminal, a method and device for detecting an FCCH (Frequency Correction Channel) frame. The method for detecting the FCCH frame comprises the steps of: receiving data of a GSM (Global System for Mobile Communication) subframe by using an idle time slot of a TD-SCDMA (Time Division Synchronous Code Division Multiple Access) subframe; carrying out FCCH frame detection on the received data of the GSM subframe; if the data of the GSM subframe, received by using the idle time slot of the current TD-SCDMA subframe, is data of a first FCCH fame in a GSM51 multiframe, obtaining effective data of the FCCH frame based on the data of the first FCCH frame and the data of the FCCH frame, received by using the idle clearance of the TD-SCDMA subframe with a fixed interval. The technical scheme of the invention aims at increasing the probability of successfully detecting the FCCH frame by the mobile terminal, reaches 100 percent detection success, and makes other dual-mode operations in parallel while making the FCCH frame detection, thereby increasing working efficiency inside the mobile terminal.

The invention discloses a global system for mobile communication (GSM) frequency deviation estimation method which comprises the following steps that: all GSM carrier frequency is searched; the carrier frequency which contains a frequency correction channel (FCCH) is locked and an FCCH signal is extracted; and frequency deviation is estimated according to the extracted FCCH signal. According to the method, the real-time performance is strong, the computing precision is high, the hardware is easy to realize, the frequency deviation value of a GSM signal can be accurately estimated, particularly the Doppler frequency deviation value of the GSM signal under a high-speed environment can be estimated in real time. The invention also discloses a GSM frequency deviation estimation system which comprises a carrier frequency searching module, an FCCH signal extraction module and a frequency deviation estimation module. According to the invention, the signal quality in a carriage can be improved on a vehicle-mounted repeater, so that the cutting off rate can be effectively improved, and the GSM signal is not off line and cannot be normally called, switched and the like.

The invention proposes for improving the overall spectral efficiency of wireless telecommunication systems, in particular of mobile communication systems, the transmission of at least one multiframe signal having a plurality of sub-frames with predefined logical channels (BCCH, FCCH, SCH) repeatedly embedded in predefined sub-frames, wherein a transmitter diversity is applied using antenna and / or polarization hopping sequences such that during the transmission of respective one multiframe, each logical channel (BCCH, FCCH, SCH) is transmitted at least two times with a different antenna and / or polarization.

The invention discloses a frequency search method and a frequency search device. The method comprises the following steps of: when a base station performs frequency search on a frequency point in a frequency point set, receiving data of one frame in a composite frame of the frequency point sent by a standard base station; before frequency correction channel (FCCH) detection, judging whether the frequency point is a broadcast control channel (BCCH) carrier frequency point according to the received signal strength indicator (RSSI) value of at least one predetermined time length of the frame, ifso, performing FCCH detection, and acquiring frequency point information of the frequency point according to the detected FCCH; otherwise, determining frequency search failure of the frequency point,forbidding executing the FCCH detection on the frequency point, and waiting for receiving the composite frame of the next frequency point. The method and the device can reduce the FCCH detection timeand improve the performance of the base station.

The embodiment of the invention provides a random access method based on a signal carrier TDMA and a base station. According to the method, networking is conducted based on a single carrier and TDMA access mode. A physical layer frame of the method comprises TDD wireless frames, the length of each TDD wireless frame is 10 ms, each TDD wireless frame comprises 10 time slots, and four continuous TDD wireless frames constitute a multi-frame, wherein the front two time slots and the later eight time slots of each TDD wireless frame are used as a carrier of a control channel and a carrier of a traffic channel respectively. The control channel comprises a broadcast control channel BCCH, a random access channel RACH, an access granted channel AGCH, a paging channel PCH, a dedicated control channel DCCH and a frequency correction channel FCCH, wherein an RACH time slot comprises a plurality of RACH sub time slots. According to the random access method based on the signal carrier, access time delay can be shortened, and the access capacity, the access speed and the transmission speed can be increased.

The invention belongs to the technical field of space-air-ground-sea integrated information networks, and particularly discloses a low-orbit satellite communication system rapid frequency acquisition method, system and terminal. The system comprises an initial estimation and compensation module, a coarse frequency offset estimation and compensation module, a fine frequency offset estimation and compensation module and a phase estimation and compensation module. According to the method, an FCCH signal m(n) and a voice DTB burst signal r(n) which are periodically broadcasted by a satellite are received, a signal x(n) is obtained through operation, and finally demodulation, coding and decoding are carried out. By adopting the technical scheme, the communication frequency offset can be effectively reduced to the minimum range, so that the mobile terminal is simple in design at the carrier synchronization processing part, the convenience and stability of the terminal are improved, and the frequency stability in the whole satellite communication process is effectively guaranteed.

In a compressed mode, a spread spectrum communication device interleaves bit units across multiple frames using an interleaver, reduces the spreading factor using a framing / spreading unit, outputs the compressed mode frames at a predetermined compressed mode frame timing, and increases the average transmission power in the compressed mode at a radio frequency transmitter. Furthermore, a handover between different frequencies is carried out by establishing synchronization to another frequency carrier, based on a first search code and a second search code which have been detected, and moreover, a handover between different communication systems is carried out by establishing synchronization to a GSM, based on an FCCH and a SCH which have been detected.

The present invention is directed toward a system and method for identifying co-channel interference in a radio network. In an exemplary method according to the present invention, a first stream of transmission data having a first received signal frequency at a first reception location for a first period of time is received. Further, the first signal frequency of the first stream of transmission data is identified. Then the transmission data is correlated against a signal template to identify a first FCCH burst frame. Then, first FCCH time data corresponding to the first FCCH burst frame is identified and the signal frequency of the first stream of transmission data and the first FCCH time data is compared to a reference file to determine one or more probable transmission cells.

The invention discloses a Tiantong satellite-borne terminal Doppler frequency compensation device and method, and belongs to the field of satellite communication. The method mainly comprises the following steps that: firstly, a terminal searches an FCCH (Frequency Control Channel) signal at a specified frequency point, estimates a signal-to-noise ratio, searches a frequency point with the best signal-to-noise ratio, estimates the signal-to-noise ratios of a resident beam and an adjacent beam FCCH channel in real time, and outputs frequency information of the resident beam FCCH channel; reading ephemeris information and a Tiantong orbital motion information file to obtain ephemeris information and Tiantong orbital motion information at the current moment; calculating a Doppler frequency offset value and a Doppler frequency offset change rate according to resident beam FCCH channel frequency information in combination with ephemeris information and Tiantong orbital motion information; and finally, compensating an uplink signal and a downlink signal of the terminal according to the Doppler frequency offset value and the Doppler frequency offset change rate. According to the invention, the problem of distortion of signals received by the satellite-borne terminal caused by large Doppler frequency offset can be solved, so that reliable communication between the satellite-borne terminal and the Tiantong satellite can be ensured.

Disclosed is a BSIC detection method for a dual mode mobile terminal under the incontinuous receiving condition, which adopts the method by using X ms as the detection time, Y ms as the detection interval, and Z as the circulatory detection times; wherein, the value of X multiplying Z is bigger than or equal to the frame period of the detected frame; the integer of the remainder that Y divided by the multiframe duration of the detected frame equals to X; X is bigger than one detected frame duration, but smaller than the detected frame period, and Z takes the relative small integer value; wherein, the detected frame is a FCCH frame or a SCH frame. The method provided by the invention can effectively avoid the risk of missing a call being called under the incontinuous receiving condition, and ensures to resolve the certain frame that needs to be detected out on the precondition of receiving frames as few as possible; thereby minimizing the detection time, saving electricity of the mobile terminal, and in particularly being suitable for the WCDMA / GSM dual mode mobile terminal.

The invention provides a GSM-R system frequency shift automatic correction method. The GSM-R system frequency shift automatic correction method includes the steps: searching 124 channels, that is, all BCH channels, performing power scanning on the channels, and selecting the strongest BCCH carrier wave to quarter; detecting an FCCH frame; searching an SCH frame after finding the next frame of the FCCH frame, and then performing demodulation; and according to the features of quick movement of a railway, quickly estimating frequency shift caused by high speed movement, and then performing compensation so as to reduce the influence of Doppler effect on GSM-R communication and improve the communication quality of the GSM-R system.

The invention relates to the technical field of communication, and provides a paging method and device in a high penetration mode in a satellite mobile communication system. The method comprises the following steps: an earth mobile terminal signal cannot detect a normal FCCH (Frequency Correction Channel) signal and a BCCH (Broadcast Control Channel) signal, but can detect a BACH (Basic Alarm Channel) signal, and the earth mobile terminal enters a high penetration state; a core network sends a normal paging message when paging the earth mobile terminal, and sends a high-penetration paging message when a paging response is not received within the duration of the timer; when the earth mobile terminal is in a high-penetration state and receives high-penetration paging, the earth mobile terminal is prompted to move to an open strong signal area so as to recover to a normal service state; the high-penetration scene enables the earth mobile terminal to receive paging under the condition of weak signals, so the use coverage scene of the whole satellite mobile communication system is perfected, the use effect of a user is improved, and the performance efficiency of the whole system is improved.