CN103384401B - Based on synchronization acquiring device and the method thereof of first in first out structure - Google Patents

Abstract

A first-in-first-out structure-based synchronization acquisition device and method thereof, the device includes a synchronization sequence acquirer, a correlator group, an FFT converter, a maximum signal selector, and a decision unit. The method comprises: (1) a synchronous sequence acquirer acquires a synchronous sequence with a symbol length; (2) a correlator group performs a segmental correlation operation on the synchronous sequence and a local reference; (3) an FFT converter performs a correlation operation on the correlator group The result is done FFT transformation; (4) the maximum signal selector selects the maximum amplitude value from the amplitude values output by the FFT converter; (5) the threshold comparator compares the maximum amplitude value with the threshold value, and stores the comparison result in FIFO recorder; (6) The FIFO detector detects the FIFO recorder under the control of the comparison result output by the threshold comparator to judge whether the synchronous capture is successful. The invention has the advantages of less resource occupation, high capture speed, low probability of missed capture and wrong capture of synchronous capture, and high probability of correct synchronous capture.

Description

Synchronization acquisition device and method based on first-in-first-out structure

technical field

The invention belongs to the technical field of communication, and further relates to a synchronization acquisition device based on a first-in-first-out structure in wireless communication and a method thereof. The invention can be used for the receiving end of the wireless communication system to capture synchronous sequence in the received signal synchronously, realize the synchronization between the receiving end and the sending end, and ensure the correct reception of information.

Background technique

In a wireless communication system, in order to correctly demodulate information, it is necessary to realize the synchronization between the receiving end and the sending end. Therefore, for a wireless communication receiver, one of the most critical issues is to achieve synchronization between the local reference sequence and the synchronization sequence in the received signal.

At present, a widely used synchronization acquisition algorithm is based on the FFT-PMF segmented matched filter method, which can obtain the frequency offset value while searching the code phase, thus turning the two-dimensional search of phase and frequency into a Dimensional search, greatly reducing capture time. However, because the wireless channel environment is constantly changing, according to the threshold comparison of the FFT-PMF segmented matched filter method to judge whether the synchronization acquisition is successful, there are problems of high probability of missed acquisition and wrong acquisition.

Beijing Chuangyi Video Technology Co., Ltd. has a patented technology "a method for synchronously capturing related results and a synchronously capturing unit" (application date: May 23, 2008, application number: 200810112499.X, authorization announcement number: CN101312375B) A method for synchronous capture is disclosed in . The implementation steps of the method are: first, search in the correlation result sequence, and record the sequence index value n corresponding to any correlation value whose amplitude value is greater than or equal to the amplitude threshold value T _amp1 ; second, delay the index value n by one time threshold value T _time , to obtain a new sequence index value n ₂ ; thirdly, starting from the index n ₂ to search the correlation result sequence backwards, and obtain the first peak amplitude value greater than the amplitude threshold value T _amp2 The corresponding sequence index value is the coarse synchronization position. The synchronization acquisition unit includes: (1) starting point index search module, used to receive the correlation result sequence and search in it, and record any amplitude value greater than or equal to the sequence index value n corresponding to the correlation value of the amplitude threshold value T _amp1 ; ( 2) A new index generation module, used to delay the index value n by a time threshold value T _time , to obtain a new sequence index value n ₂ ; (3) a peak amplitude value search module, used to start backward from n ₂ Search the amplitude value sequence of the correlation result, and the obtained sequence index value corresponding to the first peak amplitude value greater than the amplitude threshold value T _amp2 is the coarse synchronization position. This method can be applied to the synchronous capture of related results when the delay spread is large, and it is also suitable for the situation when the delay spread is not large, which is more comprehensive; at the same time, the method gives a range for the threshold value, which further gives The specific numerical value is shown, which makes the realization of the method more convenient and simple. The disadvantages of this patented technology are: the patent defines that "starting from the index n ₂ to search the relevant result sequence backwards, the obtained sequence index value corresponding to the first peak amplitude value greater than the amplitude threshold value T _amp2 is is the coarse synchronization position", however, due to the complexity of the wireless channel environment, the sequence index value corresponding to the first peak amplitude value greater than the amplitude threshold value T _amp2 is not necessarily the coarse synchronization point, and this patent does not It is not verified whether the acquired coarse synchronization position is correct or not, which increases the probability of misacquisition of synchronization capture and reduces the performance of the communication system.

Beijing Chuangyi Video Technology Co., Ltd. has a patented technology "a signal acquisition method that can resist large delay expansion channels" (application date: December 25, 2007, application number: 200710304114.5, authorization announcement number: CN100518047C) A method of synchronous capture. The implementation steps of the method are: first, according to the system parameters, setting the threshold T _amp of the autocorrelation output amplitude and the width threshold _Twid of the autocorrelation output amplitude waveform; An autocorrelation output amplitude value is greater than the first time point of the threshold T _amp ; the third, after delaying the first time period from the first time point, it is determined that the autocorrelation output amplitude value is less than the second time point of the threshold T _amp ; the fourth , starting from the second time point and searching backward in the second time period less than or equal to the signal period T ₂ until a peak is found, if the amplitude of the peak is greater than the threshold T _amp and the amplitude waveform of the peak is within the threshold T _amp If the width of the above waveform is greater than the width threshold _Twid , it is determined that the time point corresponding to the peak is the rough synchronization position of the signal; if the above conditions are not met, go to the first step and reset the parameters T _amp and _T Perform the signal capture process; or directly return to the second step, keep the parameters T _amp and T _wid unchanged, and then perform the signal capture process again. The signal acquisition method described in this invention is aimed at the signal characteristics of the extended channel with a large delay, by determining the search period including a signal, and using the peak judgment condition, a qualified peak can be quickly and accurately found from the extended signal, thereby Locating to the coarse synchronization position, therefore, it can resist the channel environment with large delay expansion and improve the probability of signal synchronization acquisition. The deficiencies of this patented technology are: the definition in the patent is "search backward from the second time point in the _second time period less than or equal to the signal period T2 until a peak is found, if the amplitude of the peak is greater than the threshold T _amp and the amplitude waveform where the peak is located and the waveform width above the threshold T _amp is greater than the width threshold T _wid , then it is determined that the time point corresponding to the peak is the rough synchronization position of the signal", but due to the complexity of the wireless channel environment, The searched coarse synchronization position may be a pseudo-synchronization point, and this method does not check the searched coarse synchronization position, which will lead to an increase in the probability of synchronization acquisition misacquisition and reduce the performance of the communication system.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art, and provide a synchronous acquisition device and method based on a first-in-first-out structure, so as to solve the problems of high probability of wrong acquisition and high probability of missing acquisition in the prior art in synchronous acquisition , to improve the performance of the communication system.

To achieve the above object, the synchronization acquisition device of the present invention includes a synchronization sequence acquirer, a correlator group, an FFT converter, a maximum signal selector, and a decision unit connected through a signal transmission line. The output end of the described synchronization sequence acquirer is connected with the input end of the correlator group, and the correlator output corresponding to the real part signal and the imaginary part signal in the correlator group is connected with the input end of the FFT converter after being added by an adder, The output end of the FFT converter is connected with the input end of the maximum signal selector, the output end of the maximum signal selector is connected with the input end of the decision device, and the output end of the decision device is connected with the input end of the synchronous sequence correlator. in,

The synchronization sequence obtainer is used to obtain a sequence of a synchronization symbol length from the received wireless transmission signal as a synchronization sequence.

The correlator group includes a plurality of correlators and a plurality of adders, the correlators are used to store the local reference sequence, and realize the correlation operation between the local reference sequence and the segmented data input by the corresponding synchronization sequence acquirer; at the same time Output the relevant operation results to the adder for accumulation processing.

The FFT converter is used for FFT transforming the data output by the adder.

The maximum signal selector is used to select the maximum peak value from the data output by the FFT converter.

Described judger comprises threshold comparator, FIFO recorder, FIFO detector; This threshold comparator is used for the output of maximum signal selector and the threshold value that programmer sets according to experience to carry out size comparison; This FIFO recorder Record corresponding data according to the comparison result of the threshold comparator; the FIFO detector judges whether the synchronization capture is successful or not according to the comparison result of the threshold comparator and the recorded data of the FIFO recorder, and feeds back the judgment result to the synchronization sequence acquirer.

The FIFO recorder in the device of the present invention includes a plurality of FIFO components and an AND gate device. The plurality of FIFO components are connected in series, the output end of each FIFO component is connected to the input terminal of the AND gate device; the input terminal of the first FIFO component is connected to the output end of the threshold comparator; The output terminal of the AND gate device is connected with the input terminal of the FIFO detector.

The FIFO components are used to store data with a length of one synchronization symbol; the number of FIFO components is equal to the number of synchronization symbols in the sync header of the wireless transmission signal received by the synchronization sequence acquirer minus 1.

The AND gate device is used for logical ANDing the input data.

Utilize above-mentioned device, the concrete steps that the present invention realizes synchronous acquisition method are as follows:

(1) Obtain the synchronization sequence:

1a) The synchronization sequence acquirer receives a wireless transmission signal that contains at least two identical synchronization symbols in the synchronization header;

1b) The address of the first data of the received wireless transmission signal is used as the starting point of the target sequence;

1c) The synchronization sequence acquirer starts from the starting point of the target sequence, and selects a sequence with the length of a synchronization symbol as the synchronization sequence.

(2) Segmentation:

2a) Divide the length of the synchronization sequence by the number of correlators in the correlator group, and the obtained quotient and remainder represent the length of the segmented sequence, and the multi-segment sequence whose length is the quotient corresponds to all but the last correlator in the correlator group A correlator; the sequence whose length is the remainder corresponds to the last correlator of the correlator group;

2b) Segment the local reference sequence according to the segmentation method in step 2a).

(3) Do related operations:

Dot-multiply the synchronization sequence corresponding to the same correlator with the local reference sequence to obtain a complex correlation signal.

(4) Do addition operation:

The adder accumulates the real part and the imaginary part of the complex correlation signal respectively to obtain a complex cumulative sum signal.

(5) Do FFT transformation:

The FFT converter performs FFT transformation on the accumulated sum signal to obtain amplitude values corresponding to the number of FFT transformation points one by one.

(6) Select the largest signal:

The maximum signal selector selects the maximum value of the amplitude peak value from the amplitude values to obtain a maximum amplitude value.

(7) Compare the size of the maximum amplitude value and the threshold value:

The threshold comparator compares the maximum amplitude value with the threshold value. If the maximum amplitude value is greater than or equal to the threshold value, the threshold comparator outputs 1 as the comparison result; if the maximum amplitude value is smaller than the threshold value, the threshold comparator outputs 0 as the comparison result. As for the comparison result, the FIFO recorder stores the comparison result of the threshold comparator; according to the first-in-first-out principle, output the data stored in the FIFO recorder.

(8) Determine whether the synchronous capture is successful:

When the comparison result output by the threshold comparator is 1, the FIFO detector detects the output of the FIFO recorder to determine whether the synchronization capture is successful: if the output data of the FIFO recorder is 1, the FIFO detector outputs the coarse synchronization position, and the synchronization capture is judged For success, execute step (9); if the output data of the FIFO recorder is 0, then use the address of the next data received by the synchronization sequence acquirer to receive the wireless transmission signal as the starting point of the target sequence, and turn to step 1c) to perform synchronization capture again .

(9) The communication system ends the synchronous acquisition state and enters the synchronous tracking state.

Compared with the prior art, the present invention has the following advantages:

The first, because the present invention adopts the FIFO recorder of first-in-first-out structure, records the comparison result that threshold comparator outputs, has overcome prior art because the problem that real synchronous point is missed because of catching false synchronous point, has reduced The probability of missed capture in synchronous capture improves the performance of the communication system.

Second, because the present invention adopts FIFO detector, when the comparison result of threshold comparator output satisfies the condition, FIFO detector judges whether synchronous capture is successful by detecting the output of FIFO recorder; At the same time, the coarse synchronization position is verified, which reduces the probability of wrong capture of synchronization capture and improves the performance of the communication system.

The 3rd, because the present invention adopts the FIFO recorder and the FIFO detector of first-in-first-out structure, under the same capture precision requirement, the device of the present invention can adopt the synchronous symbol that a plurality of symbol lengths are shorter to realize, thereby The resources needed for the correlation calculation and FFT transformation of the communication system are reduced, and the processing speed of the synchronization acquisition process is accelerated, so that the synchronization acquisition device of the present invention has the advantages of less resource occupation and high synchronization acquisition speed.

The 4th, because synchronous capture method of the present invention is when judging whether synchronous capture is successful, require only when the output of threshold comparator and the output of FIFO recorder meet condition simultaneously, just can be judged as synchronous capture success; Such judgment method, overcomes The problem of high probability of false capture and high probability of missed capture in the prior art in synchronous acquisition is solved, so that the communication system has the advantage of high probability of correct synchronous acquisition.

Description of drawings

Fig. 1 is the block diagram of device of the present invention;

Fig. 2 is the block diagram of FIFO recorder in the device of the present invention;

Fig. 3 is a flowchart of the method of the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings.

Referring to accompanying drawing 1, the device of the present invention comprises the synchronous sequence acquirer, correlator group, FFT converter, maximum signal selector, decider connected by signal transmission line. The input end of the synchronous sequence acquirer receives the wireless transmission signal, and the correlator group includes P correlators and P adders, and the output end of the synchronous sequence acquirer is respectively connected with correlator 1, correlator 2, ... correlator P The input terminals are connected, the output terminals of correlator 1, correlator 2, ... correlator P are connected with the input terminals of the adder corresponding to the correlators, the output terminals of the adder are connected with the input terminals of the FFT converter, and the FFT converter The output terminal of the maximum signal selector is connected to the input terminal of the maximum signal selector, the output terminal of the maximum signal selector is connected to the input terminal of the decision device, the output terminal of the decision device is connected to the input terminal of the synchronous sequence correlator, and the output terminal of the decision device is based on Invention of the output of the synchronization capture device.

The function of the synchronization sequence obtainer is to obtain a sequence of the length of a synchronization symbol from the received wireless transmission signal as a synchronization sequence. The correlator group includes P correlators and P adders. The correlators are used to store the local reference sequence, realize the correlation operation between the local reference sequence and the segmented data input by the corresponding synchronization sequence acquirer, and output the correlation operation result at the same time to the adder for cumulative processing. The function of the FFT converter is to perform FFT transformation on the data output by the adder. The function of the maximum signal selector is to select the peak value from the output data of the FFT converter. The decision unit includes a threshold comparator, a FIFO recorder, and a FIFO detector. The function of the threshold comparator is to compare the output of the maximum signal selector with the threshold value set by the programmer based on experience; the function of the FIFO recorder is to record the corresponding data according to the comparison result of the threshold comparator; the FIFO detector The function is to judge whether the synchronization capture is successful or not according to the comparison result of the threshold comparator and the recorded data of the FIFO recorder, and feed back the judgment result to the synchronization sequence acquirer.

With reference to accompanying drawing 2, the FIFO recorder in the device of the present invention comprises h FIFO components and an AND gate device. The output terminal of the threshold comparator is connected with the input terminal of FIFO component 1, the output terminal of FIFO component 1 is respectively connected with the input terminal of FIFO component 2 and the input terminal of AND gate device, and the output terminal of FIFO component 2 is connected with the lower The input terminal of a FIFO component is connected with the input terminal of the AND gate device, the output terminal of the FIFO component h is connected with the input terminal of the AND gate device, and the output terminal of the AND gate device is connected with the input terminal of the FIFO detector.

The function of the FIFO components is to store data with a length of one sync symbol; the number of FIFO components is equal to the number of sync symbols in the sync header of the wireless transmission signal received by the sync sequence acquirer minus 1. The function of the AND gate device is to perform logical AND operations on the input data.

Because the present invention adopts the FIFO recorder of first-in-first-out structure, no matter how the size comparison result between the output of the maximum signal selector and the threshold value of the threshold comparator is, the comparison result is recorded in the FIFO recorder, and after that In judging whether the synchronization capture is successful or not, the comparison result is detected again, which overcomes the existing problems in the prior art, and the index value corresponding to the first found amplitude value that meets the conditions is used as the rough synchronization position, and the synchronization capture process is stopped so that the The problem of missing the real coarse synchronization position reduces the probability of missing the synchronization capture of the communication system.

Because the present invention adopts the FIFO detector, when the comparison result output by the threshold comparator satisfies the condition, the FIFO detector judges whether the synchronous capture is successful by detecting the output of the FIFO recorder, and obtains the coarse synchronous position; because the data length stored in the FIFO components Equal to the length of a sync symbol, when the output data of the FIFO recorder is 1, it means that the output data of each FIFO component is 1, which means that the interval of a sync symbol length is greater than or equal to the threshold value If the comparison result output by the threshold comparator is also 1 at this time, the coarse synchronization position output by the FIFO detector is the correct synchronization position after multiple verifications, which reduces the probability of mis-capture of synchronization capture in the communication system.

Because the present invention adopts the FIFO recorder and the FIFO detector of the first-in-first-out structure, under the same acquisition accuracy requirement, the device of the present invention can be realized by using a plurality of synchronous symbols with short symbol lengths, and the synchronous symbol length becomes Shorter, the length of the local reference sequence becomes shorter, and the number of multipliers and adders is reduced when doing correlation operations and FFT changes, thus reducing the occupied resources and speeding up the processing speed of the synchronization capture process, making this The invented synchronization capture device has the advantages of less resource occupation and high synchronization capture speed.

Below in conjunction with accompanying drawing 3, the method of the present invention is described further.

In the embodiment of the present invention, the synchronization header includes two identical synchronization symbols, and a wireless transmission signal with a synchronization symbol length of M. The synchronous sequence acquirer receives the wireless transmission signal, and marks the address of the first data of the wireless transmission signal as the starting point of the target sequence as first_point.

Step 1, obtain the synchronization sequence.

The synchronization sequence acquirer starts from the first_point, and selects an M-long sequence in the wireless transmission signal as the synchronization sequence.

Step 2, segmentation.

The synchronization sequence acquirer divides the synchronization sequence into segments according to the following formula:

Y=M-XP

Wherein, P represents the number of correlators in the correlator group, and X represents the segmented symbol length of the first P-1 correlators in the corresponding correlator group, Indicates rounding down, Y indicates the segmented symbol length of the Pth correlator in the corresponding correlator group, and M indicates the length of the synchronization sequence acquired by the synchronization sequence acquirer. By this segmentation method, the synchronization sequence is divided into P segments.

The local reference sequence uses a synchronization symbol in the information sent by the information source, divides the local reference sequence into P segments according to the above segmentation method, and stores the segmented local reference sequence in the corresponding correlator.

Step 3, do correlation calculation.

The P correlators in the correlator group respectively dot-multiply the synchronization sequence corresponding to the correlator with the local reference sequence to obtain a complex correlation signal, and send the complex correlation signal to the adder for processing.

Step 4, do addition operation.

The adder accumulates the real part and the imaginary part of the complex correlation signal separately to obtain a complex sum signal, and P different adders output P different complex sum signals in total.

Step 5, perform FFT transformation.

The FFT converter performs N-point FFT transformation on P accumulated sum signals to obtain N amplitude values; among them, N≥P, that is, the number of FFT transformation points must be greater than or equal to the number of correlators in the correlator group, and the specific number of N points is corrected according to the system Select the accuracy required by the frequency offset.

Step 6, choose the largest signal.

The maximum signal selector selects a maximum amplitude value from N amplitude values, which is recorded as peak, and the position in the N point corresponding to the maximum amplitude value is marked as peak_local. Peak_local is used for frequency offset compensation during signal processing after successful synchronization capture. Has no effect in this invention.

Step 7, comparing the maximum amplitude value with the threshold value.

The threshold comparator compares the maximum amplitude value peak with the threshold value: if the peak is greater than or equal to the threshold value, the threshold comparator outputs 1 as the comparison result; if the peak is smaller than the threshold value, the threshold comparator outputs 0 as the comparison result As a result, the FIFO recorder stores the comparison result of the threshold comparator.

The threshold value is a value pre-stored in the threshold comparator after the user takes the average power of the wireless transmission signal received by the synchronization sequence acquirer as an initial value and adjusts it according to the specific wireless channel environment. When adjusting the threshold value, the user needs to consider the signal-to-noise ratio of the wireless channel environment and the number of synchronization symbols contained in the synchronization header of the wireless transmission signal; when the signal-to-noise ratio of the wireless channel environment is large, the threshold value should be increased appropriately. When the signal-to-noise ratio of the wireless channel environment is small, the threshold value should be appropriately lowered; when the number of synchronization symbols contained in the synchronization header of the wireless transmission signal is small, the threshold value should be appropriately increased. When the number of synchronization symbols is large, the threshold value should be appropriately lowered.

In the embodiment of the present invention, since the synchronization head of the wireless transmission signal uses two synchronization symbols, the FIFO recorder is composed of a FIFO component with a length M of stored data.

Step 8, judging whether the synchronization capture is successful.

When the threshold comparator outputs 1 as the comparison result, the FIFO detector detects the output of the FIFO recorder. If the output data of the FIFO recorder is 1, it is determined that the synchronization capture is successful. At this time, the position of the first_point mark is the coarse synchronization position, and the FIFO detection If the output data of the FIFO recorder is 0, add 1 to the value of first_point to point to the next data of the wireless transmission signal received by the synchronization sequence acquirer, and then go to step 1 to re-capture the synchronization .

Step 9, the communication system ends the synchronization acquisition state and enters the synchronization tracking state.

Because the synchronous capture method of the present invention, when judging whether the synchronous capture is successful, requires only when the output of the threshold comparator and the output of the FIFO recorder meet the conditions simultaneously, it can be judged as the synchronous capture success; The synchronization position, and according to the characteristics of the FIFO recorder, the correctness of the coarse synchronization position is verified, which overcomes the problems of high probability of wrong capture and high probability of missing capture in the prior art in synchronization capture, so that the communication system has correct synchronization The advantage of high probability of capture.

Claims (6)

1. A synchronous capture device based on a first-in first-out structure comprises a synchronous sequence acquirer, a correlator group, an FFT converter, a maximum signal selector and a decision device which are connected through a signal transmission line; the output end of the synchronous sequence acquirer is connected with the input end of the correlator group, the output of each correlator is connected with the input end of the FFT converter after being accumulated by the adder, the output end of the FFT converter is connected with the input end of the maximum signal selector, the output end of the maximum signal selector is connected with the input end of the decision device, and the output end of the decision device is connected with the input end of the synchronous sequence correlator; wherein,

the synchronization sequence acquirer is used for acquiring a sequence with the length of a synchronization code element from a received wireless transmission signal as a synchronization sequence;

the correlator group comprises a plurality of correlators and a plurality of adders, wherein the correlators are used for storing the local reference sequence and realizing the correlation operation between the local reference sequence and the segmented data input by the corresponding synchronous sequence acquirer; meanwhile, the correlation operation result is output to the adder for accumulation processing;

the FFT converter is used for performing FFT conversion on the data output by the adder;

the maximum signal selector is used for selecting the maximum value of the peak value from the data output by the FFT converter;

the decision device comprises a threshold comparator, an FIFO recorder and an FIFO detector; the threshold comparator is used for comparing the output of the maximum signal selector with a set threshold value, the FIFO recorder records comparison result data, the FIFO detector judges that the synchronization capture is successful according to the comparison result of the threshold comparator and the recording data of the FIFO recorder when the output of the threshold comparator and the output of the FIFO recorder meet the condition at the same time, and feeds back the judgment result to the synchronization sequence acquirer.

2. The FIFO structure based synchronous capture device of claim 1, wherein the FIFO recorder comprises a plurality of FIFO components and an AND gate component; the FIFO components are connected in series, and the output end of each FIFO component is connected with the input end of the AND gate component; the input end of the first FIFO component is connected with the output end of the threshold comparator; the output end of the AND gate device is connected with the input end of the FIFO detector; wherein,

the FIFO component is used for storing data with the length of a synchronous code element; the number of the FIFO components is equal to the number of the synchronization code elements in the synchronization head of the wireless transmission signal received by the synchronization sequence acquirer minus 1;

and the AND gate device is used for performing logical AND operation on input data.

3. A synchronous capture method based on a first-in first-out structure comprises the following steps:

(1) acquiring a synchronization sequence:

1a) a synchronization sequence acquirer receives a wireless transmission signal of which the synchronization head at least comprises two same synchronization code elements;

1b) taking the address of the first data of the received wireless transmission signal as the starting point of the target sequence;

1c) the synchronous sequence acquirer starts from the starting point of the target sequence and selects a sequence with the length of a synchronous code element as a synchronous sequence;

(2) segmenting:

2a) dividing the length of the synchronization sequence by the number of correlators in the correlator group, wherein the obtained quotient and remainder represent the length of the sequence after segmentation, and the multi-segment sequence with the length of the quotient corresponds to all correlators except the last correlator in the correlator group; the sequence with the length of the remainder corresponds to the last correlator of the correlator group;

2b) segmenting the local reference sequence according to the segmentation method in the step 2 a);

(3) and (4) performing correlation operation:

multiplying the synchronization sequence corresponding to the same correlator with a local reference sequence point to obtain a complex number correlation signal;

(4) and (4) adding operation:

the adder respectively accumulates the real part and the imaginary part of the complex correlation signal to obtain an accumulated sum signal of the complex correlation signal;

(5) performing FFT:

the FFT converter performs FFT conversion on the accumulated sum signal to obtain amplitude values corresponding to the number of FFT conversion points one by one;

(6) selecting the maximum signal:

the maximum signal selector selects the maximum value of the amplitude peak value from the amplitude values to obtain a maximum amplitude value;

(7) comparing the maximum amplitude value with the threshold value:

the threshold comparator compares the maximum amplitude value with a threshold value, and if the maximum amplitude value is larger than or equal to the threshold value, the threshold comparator outputs 1 as a comparison result; if the maximum amplitude value is smaller than the threshold value, the threshold comparator outputs 0 as a comparison result, and the FIFO recorder stores the comparison result of the threshold comparator; outputting the data stored in the FIFO recorder according to the first-in first-out principle;

(8) judging whether the synchronous capture is successful:

when the comparison result output by the threshold comparator is 1, the FIFO detector detects the output of the FIFO recorder and judges whether the synchronous capture is successful: if the output data of the FIFO recorder is 1, the FIFO detector outputs a coarse synchronization position, and if the synchronous capture is determined to be successful, the step (9) is executed; if the output data of the FIFO recorder is 0, taking the address of the next data of the wireless transmission signal received by the synchronous sequence acquirer as the starting point of the target sequence, and turning to the step 1c) to perform synchronous capture again;

(9) and the communication system finishes the synchronous acquisition state and enters a synchronous tracking state.

4. The FIFO-based synchronization acquisition method as claimed in claim 3, wherein the local reference sequence in step 2b) is a synchronization symbol in the source transmission information.

5. The FIFO-based synchronization capturing method of claim 3, wherein the threshold in step (7) is a value that the user has pre-stored in the threshold comparator after adjusting according to the specific wireless channel environment by using the average power of the wireless transmission signal received by the synchronization sequence acquirer as an initial value.

6. The FIFO-based synchronization capturing method of claim 3, wherein the coarse synchronization position in step (8) is the position corresponding to the beginning of the target sequence.