CN102271023A - Method and device for detecting system frame number of long term evolution (LTE) system - Google Patents

Abstract

The present invention relates to the field of wireless communication, in particular to a method and device for detecting a system frame number of a long-term evolution LTE system. The method utilizes the self-decoding characteristic of PBCH data of a wireless frame to equally divide a scrambling code sequence C of a TTI It is divided into 4 sections, and descrambles with the PBCH data generated in the first step; after the descrambling rate matching, choose whether to use the combination algorithm according to the situation, and then go through channel decoding and CRC check, and judge whether it is necessary according to the CRC check result Continue to receive the next wireless frame data, and determine the system frame number according to the scrambling code sequence adopted, the device of the present invention includes a receiving module (10), a signal processing module (20) and a decision module (30); the present invention can improve the terminal Blindly check the efficiency of PBCH, reduce power consumption, and determine the system frame number as soon as possible, so as to facilitate the reading of subsequent system messages.

Description

System frame number detection method and device for long term evolution LTE system

technical field

The invention relates to the field of wireless communication, in particular to a method and device for detecting a system frame number of a long term evolution LTE system.

Background technique

In order to meet people's increasing demand for data services, the 3rd generation partnership project (The ^3rd generation Partnership Project, referred to as 3GPP) launched the 3GPP "Long Term Evolution Project", referred to as 3GPP LTE (Long Term Evolution), which aims to Through the continuous evolution of the third-generation mobile communication 3G system, it provides stronger data service support and better services for users.

The LTE TDD system frame structure defined in 3GPP specification TS 36.211 is shown in Figure 1, and the LTE FDD system frame structure is shown in Figure 2.

The wireless frame length of the LTE TDD system is 10ms, corresponding to 307200Ts. Each radio frame is further divided into two 5ms half-frames, and each half-frame includes five 1ms subframes. If the uplink and downlink switching point period of the system is 5ms, the second subframe in each half frame is a special subframe, which sequentially includes downlink pilot time slot (abbreviated as DwPTS), main guard interval (abbreviated as GP), uplink pilot Timeslot (abbreviated as UpPTS). The DwPTS, GP, and UpPTS are respectively used for establishing cell identification and initial synchronization, providing uplink and downlink guard intervals, and uplink synchronization. If the uplink and downlink conversion point period of the system is 10ms, the special subframe only exists in the first half frame of the radio frame. In each half frame, 5 subframes include regular subframes in addition to special subframes, and each regular subframe includes two 0.5ms time slots. Each subframe in the radio frame is labeled i=0-9, and the time slot labels of each regular subframe are respectively 2i and 2i+1. Subframes 0, 5, and DwPTS are always used for downlink transmission, while regular subframes and UpPTS immediately after the special subframe are always used for uplink transmission.

The wireless frame length of the LTE FDD system is also 10ms, corresponding to 307200Ts. A radio frame includes 20 time slots, numbered from 0 to 19, and each time slot is 0.5ms long. A subframe consists of two consecutive time slots, that is, subframe i includes time slots 2i and 2i+1. The 10 subframes can be used for downlink transmission or uplink transmission. Uplink and downlink transmissions are separated by frequency domain.

Whether in the frame structure of the LTE TDD system or the frame structure of the LTE FDD system, subframe #0 is always used for downlink transmission, and the physical broadcast channel (Physical broadcast channel, PBCH) is only mapped to subframe #0 of the radio frame superior. The PBCH data of a transmission time interval (Transmission Time Interval, referred to as TTI) is mapped to subframe #0 of four consecutive radio frames, and the first radio frame mapped must satisfy the condition of SFN mod 4=0, where, SFN represents the system frame number, and mod represents the remainder operation.

In the LTE system, after the terminal completes the initial cell search, in order to demodulate user data, it needs to read system information first. The terminal first reads the master information block (Master Information Block, MIB) of the system message. Since the MIB is transmitted in the PBCH, the MIB can only be read by demodulating the PBCH first, and the system frame number SFN is obtained, and then the system information is interpreted according to the SFN Block 1 (System Information BlockType1, referred to as SIB1) and other system messages. The determination of the system frame number SFN is crucial to the interpretation of system messages such as SIB1.

In the LTE system, the system frame number is represented by 10 bits, among which the high 8 bits are explicitly notified in the MIB and can be known after reading the MIB; while the low 2 bits are notified implicitly through PBCH mapping, as shown in Figure 3. In a TTI, the first radio frame that maps PBCH represents 00, the second radio frame represents 01, the third radio frame represents 10, and the fourth radio frame represents 11. The received radio frame data is in a TTI The position in determines the lower 2 bits of the system frame number SFN.

According to 3GPP specifications TS 36.211 and TS 36.212, the signal processing flow of the physical broadcast channel PBCH transmitter is shown in Figure 4:

1) The 24-bit master information block MIB becomes 40 bits after adding a 16-bit cyclic redundancy check code CRC.

2) The 40-bit data after adding CRC is subjected to tail biting (Tail Biting) convolution coding to obtain 120-bit data.

3) After rate matching of the 120-bit data after channel coding, if it is a regular cyclic prefix (Cyclic Prefix, CP for short), then 1920-bit data will be obtained, and if it is an extended CP, then 1728-bit data will be obtained.

4) Generate a TTI scrambling code sequence C, and then scramble the PBCH transmission block.

5) After QPSK modulation, 960symbol (regular CP) or 864symbol (extended CP) is obtained.

6) Then go through layer mapping and precoding processing. If the number of transmit antennas is 1, adopt the layer mapping and precoding scheme based on single-antenna transmission mode; if the number of transmit antennas is 2 or 4, adopt the layer mapping and precoding scheme based on transmit diversity.

7) Mapping to physical resource units. For the number of transmitting antennas of 1, 2 or 4, the same physical resource mapping method is used, that is, no matter how many transmitting antennas are, the pilot resources of 4 antennas are always vacated; in addition, the PBCH data of one TTI is mapped to four consecutive radio frames, and the mapped first radio frame must meet the condition of SFN mod 4=0, the first 4 OFDM symbols of slot#1 of each radio frame (only occupying the 1.08MHz bandwidth (72 subcarriers) in the center of the frequency band )) is used to map PBCH data, as shown in Figure 3.

8) Finally undergo OFDM modulation to generate a PBCH baseband signal.

According to the above description, in order to determine the system frame number SFN, it is necessary not only to detect the PBCH correctly to obtain the upper 8 bits of the SFN, but also to determine the position of the received radio frame data in one TTI to obtain the lower 2 bits of the SFN. Usually, the terminal receives a complete TTI of PBCH data, and uses the reverse signal processing process of the transmitter to detect the PBCH to determine the system frame number, but this method has low processing efficiency, high complexity and terminal power. consumes more.

Contents of the invention

The technical problem solved by the present invention is to propose a system frame number detection method for the long-term evolution LTE system, which detects the PBCH by combining one radio frame or multiple radio frames, and determines the system frame number, thereby reducing the implementation complexity and functionality of the terminal. consumption, and determine the system frame number as soon as possible to facilitate the reading of subsequent system messages.

In order to solve the above problems, the present invention proposes a system frame number detection method of the Long Term Evolution LTE system, as shown in Figure 5, including:

Step A: The terminal receives the time-domain signal of the first subframe on a wireless frame, and adopts the reverse signal processing process of the transmitting end to obtain the physical broadcast channel PBCH data A to be descrambled;

Step B: Generate a scrambling code sequence C with a time interval of TTI, divide the scrambling code sequence C into 4 segments, and the length of each segment is equal to the length of data A, descramble data A with the 4 segments of scrambling code sequence in turn, and obtain 4 copies of descrambled data.

Step C: Perform de-rate matching on the 4 pieces of descrambled data respectively, and save the de-rate matching output data;

Step D: Perform channel decoding on the data after de-rate matching;

Step E: Perform a cyclic redundancy CRC check on the channel decoding output data. If any CRC check is correct, obtain the system frame number and the process ends; otherwise, go back to step A and repeat the above process until any CRC check is correct. until correct.

Preferably, as an improved implementation, after the step C saves the solution rate matching output data, it is judged whether it is the first time to receive PBCH data, if yes, then directly execute step D; otherwise, the same as the last saved solution Step D is performed after the rate matching output data is merged.

Preferably, as another improved implementation, if all CRC checks fail in the step E, it is judged whether it is the first time to receive PBCH data, if yes, then go to step A, otherwise, save the Step D is executed after the rate matching output data is merged with the rate matching output data saved last time.

The data merging is to merge the de-rate matching output corresponding to the second scrambling sequence saved this time with the de-rate matching output corresponding to the first scrambling sequence saved last time, and combine the third scrambling sequence saved this time The de-rate matching output corresponding to the scrambling code sequence is merged with the de-rate matching output corresponding to the second scrambling code sequence saved last time, and the de-rate matching output corresponding to the fourth scrambling code sequence saved this time is combined with the last saved The de-rate matching output corresponding to the third scrambling code sequence of the current scrambling code sequence is merged, while the de-rate matching output corresponding to the first scrambling code sequence saved this time does not participate in the merging; the two pieces of data are added after bit weighting.

The weighted coefficients depend on the combining manner, and the combining manner adopts selective combining, equal-gain combining, or maximum-ratio combining and the like.

In order to solve the above problems, the present invention also provides a system frame number detection device of an LTE system, including:

The receiving module 10 is configured to receive the time-domain signal of the first subframe of a radio frame for the first time, or re-receive the time-domain signal of the first subframe of a radio frame according to the decision instruction of the decision module 30;

The signal processing module 20, according to the time domain signal of the first subframe on a radio frame output by the receiving module 10, completes the signal processing flow of the PBCH receiving end, further including removing the CP unit 201, the OFDM demodulation unit 202, and the resource mapping unit 203, channel estimation unit 204, signal detection unit 205 and QPSK demodulation unit 206, scrambling code generation and descrambling unit 207, de-rate matching unit 208, channel decoding unit 209 and CRC checking unit 210;

The signal processing module 20 further includes:

PBCH counting unit 220, PBCH counts and judges whether to receive PBCH data for the first time;

The data merging unit 230 is used to combine the de-rate matching output data by means of selective merging or equal gain merging or maximum ratio merging;

Data merging unit 230 determines whether to work according to PBCH counting unit 220 judgment result, if PBCH counting unit 220 judges as receiving PBCH data for the first time, then data merging unit 230 does not work, and data is directly delivered to channel decoding unit 209, otherwise data passes through The data combining unit 230 passes the processing to the channel decoding unit 209 .

Judgment module 30 judges whether it is over according to the CRC check result of signal processing module 20, and the CRC check unit judges that if any CRC check is correct, then the high 8 bits of the system frame number are obtained from MIB, and the low 2 bits are obtained from step B Obtain the sequence number of the scrambling code sequence used in the system, thereby obtaining the system frame number; otherwise, instruct the receiving module 10 to re-receive the time domain signal of the first subframe on a radio frame.

The invention utilizes the self-decoding characteristic of the PBCH data of a wireless frame, divides the scrambling code sequence C of a TTI into four sections, and performs descrambling with the PBCH data generated in the first step respectively. After de-rate matching, choose whether to use the combination algorithm according to the situation, and then go through channel decoding and CRC check, judge whether to continue to receive the next wireless frame data according to the CRC check result, and determine the system frame according to the adopted scrambling code sequence Number. Compared with the prior art, the system frame number detection method provided by the present invention has the following beneficial effects:

1) Improve the efficiency of terminal blind detection PBCH and reduce power consumption

Although the PBCH data of a TTI is mapped to 4 consecutive radio frames for transmission, the present invention utilizes the self-decoding characteristic of the PBCH data of a radio frame, that is, the PBCH data of a radio frame is sequentially combined with 4 radio frames in a TTI The corresponding 4-segment scrambling code sequence is descrambled, so as to avoid receiving and detecting PBCH data of a complete TTI. Realize the correct detection of PBCH data in the shortest time, and determine the system frame number. Even when the channel environment is deteriorating, PBCH data can be correctly detected in a short period of time by combining PBCH data of multiple radio frames.

2) The merging algorithm is universally applicable

At the transmitter, the first radio frame mapped to the PBCH data of a TTI must satisfy the SFN mod 4 = 0 condition, and the PBCH data between two TTIs is not exactly the same. When the terminal receives data, it cannot be guaranteed to start receiving data from the first radio frame in the TTI. The terminal may start receiving PBCH data from the second, third or fourth radio frame in the TTI. No matter which radio frame in the TTI the terminal starts to receive PBCH data, it can use the combination algorithm proposed by the present invention to combine it with the data received later, so as to achieve the purpose of correct detection.

Description of drawings

Fig. 1 is prior art LTE system TDD mode frame structure;

Fig. 2 is prior art LTE system FDD mode frame structure;

FIG. 3 is a time-frequency resource mapping diagram of PBCH in the prior art;

Fig. 4 is the prior art PBCH transmitter signal processing flow;

Fig. 5 is the flow chart of the system frame number detection method of the LTE system of the present invention;

Fig. 6 is a flow chart of a preferred embodiment of the system frame number detection method of the LTE system of the present invention;

FIG. 7 is a flow chart of the second preferred embodiment of the system frame number detection method of the LTE system of the present invention;

Fig. 8 is an explanatory diagram of the merging strategy of the present invention;

9 is a structural diagram of a system frame number detection device of the LTE system of the present invention;

10 is a structural diagram of the signal processing module of the system frame number detection device of the LTE system of the present invention;

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention clearer, the method and device for detecting a system frame number of a long-term evolution LTE system of the present invention will be further described in detail below in conjunction with the accompanying drawings and implementation methods, and the known implementation methods will not be described in detail. To avoid unnecessary confusion with the content of the present invention.

A method for detecting a system frame number of a Long Term Evolution LTE system in the present invention has multiple implementation modes, which are described as follows.

Implementation mode 1: Single radio frame detection system frame number scheme, the process is shown in Figure 6, and the specific steps include:

101) The terminal receives a time-domain signal of the first subframe in a radio frame. The CP is removed from the time domain signal, and after OFDM demodulation, the center 72 subcarriers of the first 4 OFDM symbols of slot#1 on the subframe are the PBCH data and corresponding reference signals. Then, the data A to be descrambled is obtained through the steps of resource unit mapping, channel estimation, signal detection and QPSK demodulation. For regular CP, the length of data A is 480; for extended CP, the length of data A is 432;

102) Generate a scrambling code sequence C of one TTI. For a regular CP, the length of the scrambling code sequence C is 1920; for an extended CP, the length of the scrambling code sequence C is 1728. Divide the scrambling code sequence C into four segments, which are respectively marked as C1, C2, C3 and C4. The length of each segment is equal to the length of data A. Then descramble the data A obtained in step 101 with the 4 scrambling code sequences in turn to obtain descrambled data D1, D2, D3 and D4 respectively;

The generation of the scrambling code sequence C of one TTI is to generate a scrambling code sequence that is exactly the same as the scrambling code sequence C of one TTI at the transmitting end. The generation method is to set the initial value of the scrambling code sequence Indicates the cell identification number, and then generates a scrambling code sequence C referring to section 7.2 in 3GPP specification TS 36.211.

103) Descrambling the descrambled data D1, D2, D3 and D4 respectively for de-rate matching, and saving the de-rate matching output data;

104) performing channel decoding on the de-rate-matched data;

105) Perform a CRC check on the data after channel decoding. If any CRC check is correct, the high 8 bits of the system frame number are obtained from the MIB, and the low 2 bits are obtained from the serial number of the scrambling sequence adopted in step 102, thereby obtaining System frame number, otherwise, jump back to step 101 and repeat the above process until any CRC check is correct;

In the CRC check step, the check sequence is obtained by scrambling the CRC check bits and the CRC mask. Among them, the CRC check bits refer to section 5.1.1 in 3GPP specification TS 36.212, and the CRC mask refers to table 5.3.1.1-1 in 3GPP specification TS 36.211.

The lower 2 bits are obtained from the sequence number of the scrambling code sequence used in step 102. On the premise that the CRC check is correct, if the scrambling code sequence used in the second step is C1, the system of the latest received wireless frame can be deduced The lower 2 bits of the frame number are 00; if the scrambling sequence used is C2, the lower 2 bits of the system frame number are 01; if the scrambling sequence used is C3, the lower 2 bits of the system frame number are 10; If the code sequence is C4, the lower 2 bits of the system frame number are 11;

Embodiment 2: The scheme of combining multiple wireless frames to detect the system frame number is adopted. The process is shown in Figure 7, and the specific steps include:

201) The terminal receives a time-domain signal of a first subframe in a radio frame. The CP is removed from the time domain signal, and after OFDM demodulation, the center 72 subcarriers of the first 4 OFDM symbols of slot#1 on the subframe are the PBCH data and corresponding reference signals. Then, the data A to be descrambled is obtained through the steps of resource unit mapping, channel estimation, signal detection and QPSK demodulation. For regular CP, the length of data A is 480; for extended CP, the length of data A is 432;

202) Generate a TTI scrambling code sequence C. For a regular CP, the length of the scrambling code sequence C is 1920; for an extended CP, the length of the scrambling code sequence C is 1728. Divide the scrambling code sequence C into four segments, which are respectively marked as C1, C2, C3 and C4. The length of each segment is equal to the length of data A. Then descramble the data A obtained in step 201 with the 4 scrambling code sequences in turn to obtain the descrambled data D1, D2, D3 and D4 respectively;

203) The descrambled D1, D2, D3 and D4 data are respectively subjected to the de-rate matching step to obtain and save the de-rate matching output data E1, E2, E3 and E4, and determine whether the PBCH data is received for the first time, if If yes, then step 204 is directly performed; otherwise, it needs to be merged with the last saved solution rate matching output data, and then step 204 is performed;

The rate matching output data saved this time is merged with the rate matching output data saved last time, as shown in FIG. 8 . The de-rate matching output data E1, E2, E3 and E4 described in step 203 are respectively the de-rate matching output corresponding to the first scrambling code sequence, the de-rate matching output corresponding to the second scrambling code sequence, and the de-rate matching output corresponding to the third scrambling code sequence. The de-rate-matching output corresponding to the sequence corresponds to the de-rate-matching output corresponding to the fourth scrambling code sequence. When merging, always merge the de-rate matching output corresponding to the second scrambling sequence saved this time with the de-rate matching output corresponding to the first scrambling sequence saved last time, and merge the third scrambling sequence saved this time The de-rate matching output corresponding to the scrambling code sequence is merged with the de-rate matching output corresponding to the second scrambling code sequence saved last time, and the de-rate matching output corresponding to the fourth scrambling code sequence saved this time is combined with the last saved The de-rate matching output corresponding to the third scrambling code sequence of the current scrambling code sequence is merged, and the de-rate matching output corresponding to the first scrambling code sequence saved this time does not participate in the merging; the two pieces of data are added after bit weighting;

The weighted coefficients depend on the combination method, which may be selective combination, equal-gain combination, or maximum-ratio combination, etc., and will not be listed one by one. The manners of selective combining, equal gain combining or maximum ratio combining are well known to those skilled in the art, and thus will not be described in detail.

204) Decoding the rate-matching output data E1, E2, E3 and E4 through channel decoding;

205) Perform CRC check on the data after channel decoding. If any CRC check is correct, the high 8 bits of the system frame number are obtained from the MIB, and the low 2 bits are obtained from the serial number of the scrambling sequence adopted in step 202, thereby obtaining system frame number, the process ends; otherwise, jump back to step 201. Until the CRC check is correct.

Embodiment 3: The frame number scheme of a single radio frame and multiple radio frames combined with a hybrid detection system. The specific implementation steps include:

301) The terminal receives a time-domain signal of a first subframe in a radio frame. The CP is removed from the time domain signal, and after OFDM demodulation, the center 72 subcarriers of the first 4 OFDM symbols of slot#1 on the subframe are the PBCH data and corresponding reference signals. Then, the data A to be descrambled is obtained through the steps of resource unit mapping, channel estimation, signal detection and QPSK demodulation. For regular CP, the length of data A is 480; for extended CP, the length of data A is 432;

302) Generate a TTI scrambling code sequence C. For a regular CP, the length of the scrambling code sequence C is 1920; for an extended CP, the length of the scrambling code sequence C is 1728. Divide the scrambling code sequence C into four segments, which are respectively marked as C1, C2, C3 and C4. The length of each segment is equal to the length of data A. Then descramble the data A obtained in step 301 with the 4 scrambling code sequences in turn to obtain the descrambled data D1, D2, D3 and D4 respectively;

303) respectively subjecting the descrambled data of D1, D2, D3 and D4 to the rate de-matching step to obtain and save the de-rate matching output data E1, E2, E3 and E4;

304) Decoding the rate-matching output data through channel decoding;

305) Perform CRC check on the data after channel decoding. If any CRC check is correct, the high 8 bits of the system frame number are obtained from the MIB, and the low 2 bits are obtained from the sequence number of the scrambling sequence adopted in step 302, thereby obtaining System frame number, the process ends; otherwise, continue to execute step 306;

306) judge whether to receive PBCH data for the first time, if yes, then jump back to step 301; Otherwise, then the solution rate matching output data E1, E2, E3 and E4 that step 303 saves are respectively matched with the solution rate of saving last time The output data is merged to obtain e1, e2, e3 and e4;

307) Channel decoding the combined data e1, e2, e3 and e4 respectively;

308) Perform CRC check on the data after channel decoding. If any CRC check is correct, the high 8 bits of the system frame number are obtained from the MIB, and the low 2 bits are obtained from the serial number of the scrambling sequence adopted in step 302, thereby obtaining System frame number. Otherwise, jump back to step 301 until any CRC check is correct.

In order to achieve the above object, the present invention also provides a system frame number detection device of an LTE system, as shown in FIG. 9 . The system frame number detecting device of LTE system of the present invention comprises:

The receiving module 10 is configured to receive the time-domain signal of the first subframe of a radio frame for the first time, or re-receive the time-domain signal of the first subframe of a radio frame according to the decision instruction of the decision module 30 .

The signal processing module 20, according to the time domain signal of the first subframe on a radio frame output by the receiving module 10, completes the signal processing flow of the PBCH receiving end, further including removing the CP unit 201, the OFDM demodulation unit 202, and the resource mapping unit 203, channel estimation unit 204, signal detection unit 205 and QPSK demodulation unit 206, scrambling code generation and descrambling unit 207, de-rate matching unit 208, channel decoding unit 209 and CRC checking unit 210, as shown in FIG. 10 .

Preferably, the signal processing module 20 further includes:

PBCH counting unit 220, PBCH counts and judges whether to receive PBCH data for the first time;

The data merging unit 230 is used to combine the de-rate matching output data by means of selective merging or equal gain merging or maximum ratio merging;

Data merging unit 230 determines whether to work according to PBCH counting unit 220 judgment result, if PBCH counting unit 220 judges as receiving PBCH data for the first time, then data merging unit 230 does not work, and data is directly delivered to channel decoding unit 209, otherwise data passes through The data combining unit 230 passes the processing to the channel decoding unit 209 .

Judgment module 30 judges whether it is over according to the CRC check result of signal processing module 20, and the CRC check unit judges that if any CRC check is correct, then the high 8 bits of the system frame number are obtained from MIB, and the low 2 bits are obtained from step B Obtain the sequence number of the scrambling code sequence used in the system, thereby obtaining the system frame number; otherwise, instruct the receiving module 10 to re-receive the time domain signal of the first subframe on a radio frame.

The implementation modes or examples of the present invention further describe the purpose, technical solutions and advantages of the present invention in detail. It should be understood that the above implementation modes or examples are only preferred implementation modes of the present invention. It is not intended to limit the present invention, and any modification, equivalent replacement, improvement, etc. made to the present invention within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (7)

1. the System Frame Number detection method of a Long Term Evolution LTE system is characterized in that, comprising:

Steps A: terminal receives the time-domain signal of first subframe on the radio frames, adopts the signal processing with the transmitting terminal contrary, obtains treating the Physical Broadcast Channel PBCH data A of descrambling;

Step B: produce the scrambler sequence C of a time interval TTI, scrambler sequence C is divided into 4 sections, every segment length equals the length of data A, and data A is carried out descrambling with 4 sections scrambler sequence successively, obtains data behind 4 parts of descramblings respectively;

Step C: the data behind 4 parts of descramblings are done separated rate-matched respectively, preserve and separate the rate-matched dateout;

Step D: the data that will separate after the rate-matched are done channel decoding;

Step e: the channel decoding dateout is done the cyclic redundancy CRC check, if there is any CRC check correct, then obtain System Frame Number, flow process finishes; Otherwise, go back to steps A, repeat above process till arbitrary CRC check is correct.

2. the System Frame Number detection method of LTE system according to claim 1 is characterized in that, described step C preserve separate the rate-matched dateout after, judge whether to receiving for the first time the PBCH data, if, direct execution in step D then; Otherwise the rate-matched dateout of separating of preserving with the last time merges back execution in step D.

3. the System Frame Number detection method of LTE system according to claim 1, it is characterized in that, if all CRC check of described step e are all failed, then judge whether to receiving for the first time the PBCH data, if, then forward steps A to, otherwise the rate-matched dateout of separating that the rate-matched dateout preserves with the last time respectively of separating that step C is preserved merges back execution in step D.

4. as the System Frame Number detection method of LTE system as described in claim 2 or 3, it is characterized in that, rate-matched output the separate rate-matched output corresponding with first section scrambler sequence of preserving last time of separating that described data are merged into second section scrambler sequence correspondence of this preservation merges, rate-matched output the separate rate-matched output corresponding with second section scrambler sequence of preserving last time of separating of the 3rd section scrambler sequence correspondence of this preservation is merged, rate-matched output the separate rate-matched corresponding with the 3rd section scrambler sequence of preservation last time of separating of the 4th section scrambler sequence correspondence of this preservation exported and merged; Addition after the two segment data contraposition weightings.

5. as the System Frame Number detection method of LTE system as described in the claim 4, it is characterized in that the coefficient of described weighting depends on the merging mode, the merging mode adopts selects merging or equal gain combining or high specific to merge mode.

6. the System Frame Number checkout gear of a Long Term Evolution LTE system is characterized in that, comprising:

Receiver module (10) is used for receiving first the time-domain signal of first subframe on the radio frames, perhaps receives the time-domain signal of first subframe on the radio frames again according to the judgement indication of judging module (30);

Signal processing module (20), time-domain signal according to first subframe on the radio frames of receiver module (10) output, finish PBCH receiving end signal handling process, further comprise remove cyclic prefix CP unit (201), OFDM demodulating unit (202), separate resource map unit (203), channel estimating unit (204), detecting signal unit (205), QPSK demodulating unit (206), scrambler generates and descrambling unit (207), separate rate-matched unit (208), channel decoding unit (209) and CRC check unit (210);

Judging module (30), CRC check result according to signal processing module (20) judges whether to finish, if described CRC check unit judges has any CRC check correct, then the high 8bit of System Frame Number obtains from MIB, low 2bit obtains from the sequence number of the scrambler sequence of employing, thereby obtains System Frame Number; Otherwise indication receiver module (10) receives the time-domain signal of first subframe on the radio frames again.

7. as the System Frame Number checkout gear of LTE system as described in the claim 6, it is characterized in that described signal processing module (20) further comprises:

PBCH counting unit (220), the PBCH counting also judges whether to receiving for the first time the PBCH data;

Data merge cells (230) adopts and selects merging or equal gain combining or high specific merging mode to merge separating the rate-matched dateout;

Data merge cells (230) determines whether work according to PBCH counting unit (220) judged result, if being judged as, PBCH counting unit (220) receives the PBCH data for the first time, then data merge cells (230) is not worked, data are directly passed to channel decoding unit (209), otherwise data pass to channel decoding unit (209) after data merge cells (230) is handled.

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