CN107911328B - Frame synchronization judging device and judging method - Google Patents
Frame synchronization judging device and judging method Download PDFInfo
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- CN107911328B CN107911328B CN201711124149.0A CN201711124149A CN107911328B CN 107911328 B CN107911328 B CN 107911328B CN 201711124149 A CN201711124149 A CN 201711124149A CN 107911328 B CN107911328 B CN 107911328B
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Abstract
The invention discloses a frame synchronization judging device and a judging method, wherein the frame synchronization judging device comprises: the device comprises an input cache module, a parallel matching filter, a relative threshold judgment module, an original synchronous sequence serial matching filter, an inverted sequence synchronous sequence serial matching filter, a correlation peak comparison module and an absolute threshold judgment module; the parallel matched filter outputs a parallel matched filtering result; the relative threshold judgment module is used for judging relative thresholds; the original synchronous sequence serial matching filter and the reverse synchronous sequence serial matching filter are used for serial matching filtering; the correlation peak comparison module is used for calculating and outputting a difference value between correlation peaks; and the absolute threshold judgment module is used for carrying out fixed threshold judgment. By the technical scheme of the invention, the false alarm rate and the false alarm rate are balanced from two dimensions of the threshold and the frame format, and the reliability of frame synchronization judgment is improved by combining the self-adaptive threshold and the fixed threshold.
Description
Technical Field
The present invention relates to the field of wireless communication technologies, and in particular, to a frame synchronization decision device and a frame synchronization decision method.
Background
With the rapid development of high-dynamic platforms such as unmanned aerial vehicles and the like, information resource sharing between nodes is more and more urgent, and in high-dynamic communication, the error and reliability of frame synchronization are main factors influencing the system performance. The frame synchronization method is classified into a data-assisted synchronization method and a blind synchronization method according to whether or not assistance is given to auxiliary data, and the data-assisted synchronization method has high synchronization accuracy and thus is widely used.
In the prior art, an OFDM synchronization method with multi-threshold decision is proposed, which improves the anti-interference capability of the system by reasonably designing a synchronization sequence, and performs joint decision on two related peaks by setting a plurality of relative thresholds, so that the system can be accurately synchronized within a larger signal-to-noise ratio range, and the synchronization stability of the system is improved. The method avoids the frequency band where the interference is located in the frequency domain, and inhibits the influence of the interference on the available frequency band by windowing in the time domain, thereby improving the anti-interference capability of the system. The method sets a plurality of relative thresholds to carry out combined judgment on two correlation peaks, adaptively selects different thresholds under different signal-to-noise ratios, improves the synchronous capture probability, reduces the false synchronization probability and improves the stability of the synchronization performance. The method has the disadvantages that the feasibility of frequency domain perception and avoidance implementation under a high dynamic environment is not considered; the influence of the missed capture probability of a single synchronization sequence on a communication link under a complex channel environment is not considered; it does not consider synchronization methods of other wireless communication protocols than the OFDM system.
In addition, a method and a device for adaptively adjusting a threshold value are provided, wherein the threshold value is correspondingly adjusted according to the information of the receiving condition of the data packet by acquiring the information of the receiving condition of the data packet. The method can realize the self-adaptive adjustment of the threshold value, thereby being suitable for the requirement of the rapidly changing wireless environment and improving the communication quality. The method can solve the problems that the traditional unmanned aerial vehicle frequency division multiplexing continuous communication system is high in power consumption and not beneficial to miniaturization, an external synchronization mode with a GPS second pulse signal as an auxiliary means is adopted, and the problems of capture leakage or communication interruption and the like are caused under a severe channel. The method has the disadvantages that the method does not analyze the method for improving the communication reliability from the physical link point of view, but highly depends on the response protocol and the relevant information in the data packet to adjust the threshold value, so that the reliable synchronization under the high dynamic environment cannot be ensured.
Disclosure of Invention
In view of at least one of the above problems, the present invention provides a frame synchronization decision device and a decision method, wherein N repeated frame synchronization sequences and a reverse synchronization sequence are designed in a data header, and a normalized threshold value is appropriately increased, so that a false alarm rate is reduced while a false alarm rate is maintained at a reduced level by using the repeated synchronization sequences. When one sequence in the N repeated frame synchronization sequences is captured, the system enters a tracking state, the system starts to respectively carry out serial matching filtering on the synchronization sequence and the reverse synchronization sequence, the size of the correlation peak value of the reverse synchronization sequence and the size of the correlation peak value of the original synchronization sequence are compared by utilizing the strong autocorrelation characteristic of the synchronization sequence, and when the difference between the two is larger than a fixed threshold, the frame synchronization is finished. The false alarm rate and the false alarm rate are balanced from two dimensions of the threshold and the frame format, and the reliability of frame synchronization judgment is improved by combining the self-adaptive threshold and the fixed threshold.
In order to achieve the above object, the present invention provides a frame synchronization decision device, including: the device comprises an input cache module, a parallel matching filter, a relative threshold judgment module, an original synchronous sequence serial matching filter, an inverted sequence synchronous sequence serial matching filter, a correlation peak comparison module and an absolute threshold judgment module;
the input buffer module is used for receiving and buffering data frames and providing data sources to be correlated for the parallel matched filter;
the parallel matched filter is connected with the input cache module and is used for carrying out correlation operation on the cached data frame and the local pseudorandom sequence and outputting a correlation peak value as a parallel matched filtering result;
the relative threshold judgment module is connected with the parallel matched filter and is used for carrying out relative threshold judgment on the parallel output correlation peak values, when the relative threshold judgment quantity is larger than a preset threshold value, the serial number corresponding to the correlation peak value and the successfully-captured identification are output, otherwise, the unsuccessfully-captured identification is output;
the original synchronous sequence serial matching filter is connected with the relative threshold judging module and used for calculating the start bit of the effective data frame according to the time of successfully capturing the identification, performing related operation on the input data frame and the local pseudorandom sequence from the start bit and outputting a first serial matching filtering result;
the reverse sequence synchronous serial matched filter is connected with the relative threshold judging module and used for calculating the initial bit of the effective data frame according to the time of successfully capturing the identification, performing related operation on the input data frame and the reverse sequence form of the local pseudo-random sequence from the initial bit and outputting a second serial matched filtering result;
the correlation peak comparison module is respectively connected with the original synchronous sequence serial matched filter and the inverted synchronous sequence serial matched filter and is used for calculating and outputting a difference value between correlation peaks of the first serial matched filtering result in the original synchronous sequence serial matched filter and the second serial matched filtering result in the inverted synchronous sequence serial matched filter;
the absolute threshold decision module is respectively connected with the correlation peak comparison module, the original synchronization sequence serial matching filter and the reverse synchronization sequence serial matching filter and is used for making fixed threshold decision on the difference value obtained by the correlation peak module, outputting a synchronization completion identifier when the difference value is larger than a fixed threshold value, and otherwise, outputting a synchronization completion identifier;
the data head of the data frame comprises at least two repeated frame synchronization sequences and a reverse synchronization sequence.
In the foregoing technical solution, preferably, a buffer size of the input buffer module is L × Q, where L is a length of a received data header, and Q is an upsampling multiple of each symbol.
In the above technical solution, preferably, the parallel matched filter is configured to perform Q-fold extraction on the data in the input buffer module, perform parallel correlation with the local pseudorandom sequence in sequence, and output a correlation peak value beat by beat.
In the above technical solution, preferably, the relative threshold decision module is configured to estimate a power value of an input data frame, and divide the power value by a correlation peak value output by the parallel matched filter to obtain a relative threshold decision quantity; and when the relative threshold decision quantity is larger than the preset threshold value, outputting a serial number corresponding to the peak value, and simultaneously outputting the successfully-captured identifier, otherwise, outputting the unsuccessfully-captured identifier.
The invention also provides a frame synchronization judgment method, which comprises the following steps: receiving a data frame and caching the data frame;
performing parallel matched filtering on the data frame and a local pseudorandom sequence, and outputting a related peak value obtained by the parallel matched filtering as a parallel matched filtering result;
calculating relative threshold decision quantity of the parallel matched filtering result, and judging whether the relative threshold decision quantity is larger than a preset threshold value or not;
if so, outputting a serial number corresponding to the correlation peak value and a successfully-captured identifier, otherwise, outputting an unsuccessfully-captured identifier, and continuing to perform parallel matched filtering;
calculating the start bit of the effective data frame according to the time of the successfully captured identifier, and respectively performing serial matched filtering on the data frame and the reverse sequence of the local pseudorandom sequence from the start bit;
calculating and outputting a difference value between correlation peaks of results of the two serial matched filtering;
judging whether the difference value is larger than a preset fixed threshold value, if so, outputting a synchronization completion identifier, otherwise, outputting a synchronization incomplete identifier, and continuing to perform serial matching filtering;
the data head of the data frame comprises at least two repeated frame synchronization sequences and a reverse synchronization sequence.
In the above technical solution, preferably, the parallel matched filtering the data frame and the local pseudorandom sequence, and outputting a correlation peak obtained by the parallel matched filtering as a parallel matched filtering result specifically includes:
down-sampling the data frame to make the sampling point rate consistent with the local pseudo-random sequence in the parallel matched filter;
multiplying the down-sampled data frames by corresponding local pseudo-random sequences respectively;
and respectively adding the multiplication results according to the real part and the imaginary part to obtain the correlation peak value of the parallel matched filtering.
In the foregoing technical solution, preferably, the calculating a relative threshold decision quantity of the parallel matched filtering result, and determining whether the relative threshold decision quantity is greater than a preset threshold specifically includes: accumulating and summing the input data frames with fixed length to be used as signal power estimation quantity; calculating a quotient of the signal power estimator and a correlation peak of the parallel matched filtering result as a relative threshold decision quantity; and calculating the difference between the relative threshold decision quantity and the preset threshold value, and judging whether the difference value is greater than zero.
In the foregoing technical solution, preferably, the calculating a start bit of an effective data frame according to the time of the successful capture identifier, and performing serial matched filtering on the data frame, the local pseudorandom sequence, and a reverse sequence of the local pseudorandom sequence from the start bit specifically includes:
calculating the start bit of the effective data frame according to the time of successfully capturing the identification, performing serial matched filtering on the input data frame and the local pseudorandom sequence from the start bit, and outputting a first serial matched filtering result;
and calculating the start bit of the effective data frame according to the time of successfully capturing the identification, performing serial matched filtering on the input data frame and the reverse sequence form of the local pseudorandom sequence from the start bit, and outputting a second serial matched filtering result.
In the above technical solution, preferably, the buffered data frames are shifted according to a first-in first-out order.
In the above technical solution, preferably, the fixed length of the input data frame is far greater than the length of the received data header.
Compared with the prior art, the invention has the beneficial effects that: n repeated frame synchronization sequences and a reverse sequence synchronization sequence are designed in the data head, and the normalized threshold value is properly increased, so that the false alarm rate is reduced, and meanwhile, the false alarm rate is kept at a lower level by using the repeated synchronization sequences. When one sequence in the N repeated frame synchronization sequences is captured, the system enters a tracking state, the system starts to respectively carry out serial matching filtering on the synchronization sequence and the reverse synchronization sequence, the size of the correlation peak value of the reverse synchronization sequence and the size of the correlation peak value of the original synchronization sequence are compared by utilizing the strong autocorrelation characteristic of the synchronization sequence, and when the difference between the two is larger than a fixed threshold, the frame synchronization is finished. The false alarm rate and the false alarm rate are balanced from two dimensions of the threshold and the frame format, and the reliability of frame synchronization judgment is improved by combining the self-adaptive threshold and the fixed threshold.
Drawings
Fig. 1 is a schematic block diagram of a frame synchronization decision device according to an embodiment of the present invention;
fig. 2 is a schematic data flow diagram of a frame synchronization decision device according to an embodiment of the present invention;
FIG. 3 is a diagram of a frame header format of a data header according to an embodiment of the present invention;
fig. 4 is a schematic flow chart of a frame synchronization decision method according to an embodiment of the present invention;
fig. 5 is a flowchart of a frame synchronization decision method according to an embodiment of the present invention.
In the drawings, the correspondence between each component and the reference numeral is:
11. the device comprises an input buffer module, 12 a parallel matching filter, 13 a relative threshold decision module, 14 an original synchronous sequence serial matching filter, 15 an inverted sequence synchronous sequence serial matching filter, 16 a correlation peak comparison module and 17 an absolute threshold decision module.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
The invention is described in further detail below with reference to the attached drawing figures:
as shown in fig. 1 to 3, a frame synchronization determining apparatus provided in accordance with the present invention includes: the device comprises an input buffer module 11, a parallel matched filter 12, a relative threshold judgment module 13, an original synchronous sequence serial matched filter 14, an inverted synchronous sequence serial matched filter 15, a correlation peak comparison module 16 and an absolute threshold judgment module 17; an input buffer module 11, configured to receive and buffer data, and provide a data source to be correlated for the parallel matched filter 12; the parallel matched filter 12 is connected with the input cache module 11 and is used for performing correlation operation on cached data and a local pseudorandom sequence and outputting a correlation peak value as a parallel matched filtering result; the relative threshold decision module 13 is connected to the parallel matched filter 12 and is configured to perform relative threshold decision on the parallel output correlation peak values, and when the relative threshold decision amount is greater than a preset threshold value, output a sequence number corresponding to the correlation peak value and a successful capture identifier, otherwise output an unsuccessful capture identifier; the original synchronization sequence serial matching filter 14 is connected with the relative threshold decision module 13, and is used for calculating the start bit of the effective data according to the time of successfully capturing the identification, performing related operation on the input data and the local pseudo-random sequence from the start bit, and outputting a first serial matching filtering result; the reverse sequence synchronous serial matching filter 15 is connected with the relative threshold decision module 13 and used for calculating the start bit of the effective data according to the time of successfully capturing the identification, performing related operation on the input data and the reverse sequence form of the local pseudo-random sequence from the start bit and outputting a second serial matching filtering result; the correlation peak comparison module 16 is respectively connected with the original synchronization sequence serial matched filter 14 and the reverse synchronization sequence serial matched filter 15, and is used for calculating and outputting the difference value between the correlation peaks of the first serial matched filtering result and the second serial matched filtering result; the absolute threshold decision module 17 is respectively connected with the correlation peak comparison module 16, the original synchronization sequence serial matching filter 14 and the reverse synchronization sequence serial matching filter 15, and is used for making a fixed threshold decision on the correlation peak difference value output by the correlation peak comparison module 16, outputting a synchronization completion identifier when the difference value is greater than a fixed threshold value, and otherwise, outputting a synchronization incomplete identifier; the data head of the data comprises at least two repeated frame synchronization sequences and a reverse-order synchronization sequence.
In this embodiment, the false alarm rate is reduced by designing N repeated frame synchronization sequences and a reverse synchronization sequence in the data header (the frame header format is shown in fig. 1), and appropriately increasing the normalized threshold value, so that the false alarm rate is reduced while the false alarm rate is maintained at a reduced level by using the repeated synchronization sequences. When one sequence in the N repeated frame synchronization sequences is captured, the system enters a tracking state, the system starts to respectively carry out serial matching filtering on the synchronization sequence and the reverse synchronization sequence, the size of a synchronization sequence correlation peak value P1 of the reverse sequence and the size of an original synchronization sequence correlation peak value P2 are compared by using the strong autocorrelation characteristic of the synchronization sequence, and when the difference between P1 and P2 is larger than a fixed threshold, frame synchronization is completed. The false alarm rate and the false alarm rate are balanced from two dimensions of the threshold and the frame format, and the reliable judgment of the frame synchronization is realized by combining the self-adaptive threshold and the fixed threshold.
In the above embodiment, preferably, the buffer size of the input buffer module 11 is L × Q, where L is the length of the received data header and Q is an upsampling multiple of each symbol.
In the above embodiment, preferably, the parallel matched filter 12 is configured to perform Q-time extraction on the data frames input into the buffer module 11, perform parallel correlation with the local pseudo-random sequences in sequence, and output correlation peaks beat by beat.
In the above embodiment, preferably, the relative threshold decision module 13 is configured to estimate a power value of the input data frame and divide the power value by the correlation peak output by the parallel matched filter 12 to obtain a relative threshold decision quantity; and when the relative threshold decision quantity is larger than the threshold value, outputting the serial number corresponding to the peak value, and simultaneously outputting a successfully-captured identifier, otherwise, outputting an unsuccessfully-captured identifier.
In the above embodiment, preferably, the original synchronization sequence serial matched filter 14 adopts a serial matched filtering form, calculates the start bit of the valid data according to the time of successfully capturing the identifier, performs a correlation operation on the input data and the local pseudorandom sequence from the start bit, and outputs a serial matched filtering result; the reverse sequence synchronous sequence serial matching filter 15 adopts a serial matching filtering form, calculates the start bit of the effective data according to the time of successfully capturing the identification, performs related operation on the input data and the reverse sequence form of the local pseudo random sequence from the start bit, and outputs a serial matching filtering result;
as shown in fig. 4 and fig. 5, the present invention further provides a frame synchronization determining method, including: step S101, receiving a data frame and caching the data frame; step S102, parallel matched filtering is carried out on the data frame and the local pseudo-random sequence, and a related peak value obtained by the parallel matched filtering is output as a parallel matched filtering result; step S103, calculating a relative threshold decision quantity of the parallel matched filtering result, and judging whether the relative threshold decision quantity is larger than a preset threshold value; step S104, if the judgment is yes, outputting a serial number corresponding to the correlation peak value and an acquisition success identification, otherwise, outputting an acquisition unsuccessful identification, and continuing to perform parallel matched filtering; step S105, calculating the start bit of the effective data according to the time of successfully capturing the identification, and respectively performing serial matched filtering on the data frame and the reverse sequence of the local pseudo-random sequence from the start bit; step S106, calculating and outputting the difference value between the correlation peaks of the results of the two serial matched filtering; and step S107, judging whether the difference value is larger than a preset fixed threshold value, if so, outputting a synchronization completion identifier, otherwise, outputting a synchronization incomplete identifier, and continuing to perform serial matching filtering.
In the foregoing embodiment, preferably, performing parallel matched filtering on the data frame and the local pseudorandom sequence, and outputting a correlation peak obtained by the parallel matched filtering as a parallel matched filtering result specifically includes: down-sampling the data frame to make the sampling point rate consistent with the local pseudo-random sequence in the parallel matched filter 12; multiplying the down-sampled data frames by corresponding local pseudo-random sequences respectively; and respectively adding the multiplication results according to the real part and the imaginary part to obtain the correlation peak value of the parallel matched filtering.
In the foregoing embodiment, preferably, the calculating a relative threshold decision quantity of the parallel matched filtering result, and the determining whether the relative threshold decision quantity is greater than a preset threshold specifically includes: accumulating and summing the input data frames with fixed length to be used as signal power estimation quantity; calculating the quotient of the signal power estimator and the correlation peak value of the parallel matched filtering result as relative threshold decision quantity; and (4) calculating the difference between the relative threshold decision quantity and the threshold value, and judging whether the difference value is larger than zero.
In the foregoing embodiment, preferably, calculating a start bit of valid data according to a time point at which the capturing of the successful identifier is performed, and performing serial matched filtering on the data and the reverse order of the local pseudorandom sequence and the local pseudorandom sequence from the start bit specifically includes: calculating the start bit of the effective data frame according to the time of successfully capturing the identification, performing serial matched filtering on the input data frame and the local pseudorandom sequence from the start bit, and outputting a first serial matched filtering result; and calculating the start bit of the effective data according to the time of successfully capturing the identification, performing serial matched filtering on the input data frame and the reverse sequence form of the local pseudorandom sequence from the start bit, and outputting a second serial matched filtering result.
In the above embodiment, preferably, the buffered data frames are shifted in a first-in first-out order.
In the above embodiment, preferably, the fixed length of the input data frame is much larger than the length of the received data header.
Therefore, the frame synchronization decision method mentioned in the above embodiment includes:
step 1, inputting cache: the input data frame is stored in the input buffer module 11 and shifted in the first-in first-out order for partial correlation;
step 2, parallel matched filtering:
step 2-1, down-sampling the received signal to make the sampling point rate consistent with the local pseudo-random sequence in the parallel matched filter 12;
step 2-2, multiplying the down-sampled signals by corresponding local pseudo-random sequences respectively;
step 2-3, adding the multiplied results according to the real part and the imaginary part respectively to obtain the related peak value of the parallel matched filtering;
step 3, calculating a relative threshold decision quantity:
step 3-1, performing accumulation summation on input signals with fixed length M (M > > L) to serve as signal power estimation quantities;
step 3-2, calculating the quotient of the signal power estimator and the correlation peak value output by the parallel matched filtering as a relative threshold decision quantity;
step 4, relative threshold judgment: comparing the relative threshold quantity with a threshold value, outputting a serial number corresponding to the peak value and a successfully-captured identifier when the relative threshold decision quantity is larger than the threshold value, otherwise, outputting an unsuccessfully-captured identifier, and continuing to perform parallel matched filtering;
step 5, serial matched filtering:
step 5-1, calculating the start bit of the effective data frame according to the time of successfully capturing the identification, performing related operation on the input data frame and the local pseudo-random sequence from the start bit, and outputting a serial matching filtering result;
step 5-2, calculating the start bit of the effective data frame according to the time of successfully capturing the identification, performing related operation on the input data frame and the reverse sequence form of the local pseudo-random sequence from the start bit, and outputting a serial matching filtering result;
step 6, solving the difference value between the inverted sequence correlation peak and the original sequence correlation peak: according to the correlation peak output by the reverse sequence synchronization sequence serial matching filter 15 and the original synchronization sequence serial matching filter 14, the difference value of the two is calculated;
step 7, fixed threshold judgment: and (4) making a fixed threshold judgment on the correlation peak difference value output by the serial matching filter, outputting a synchronization completion identifier when the difference value is greater than a fixed threshold value, otherwise, outputting a synchronization incomplete identifier, and continuing to perform serial matching filtering.
In the above embodiment, N repeated frame synchronization sequences and a reverse synchronization sequence are designed in the data header, so that the autocorrelation characteristic and the cross-correlation characteristic of the pseudorandom sequence can be fully utilized to capture the accurate position of the frame header under the condition of the same hardware resources, and the problem of phase ambiguity of multiple repeated frame synchronization sequences is solved at the same time.
In the above embodiment, the false alarm rate and the false alarm rate are balanced in two dimensions of the threshold and the frame format, and the false alarm rate is reduced while the false alarm rate is reduced by properly increasing the normalized threshold value and maintaining the false alarm rate at a reduced level by using the repeated synchronization sequence, thereby solving the problem that the false alarm rate and the false alarm rate are mutually limited in one dimension;
in the above embodiment, the reliable determination of frame synchronization is implemented by combining the adaptive threshold and the fixed threshold, on one hand, the adaptive threshold is used to contain the power jitter of the received signal, and on the other hand, the fixed threshold is used to determine the difference between the original sequence correlation peak and the reverse sequence correlation peak, thereby implementing the accurate and reliable capture of the frame synchronization sequence.
The above-mentioned embodiments of the present invention provide a frame synchronization decision device and a decision method, which, in consideration of the technical problems of unbalanced false alarm rate and poor reliability of the frame synchronization process in the prior art, design N repeated frame synchronization sequences and a reverse synchronization sequence in the data header, and properly increase the normalized threshold value, thereby reducing the false alarm rate and simultaneously maintaining the false alarm rate at a reduced level by using the repeated synchronization sequences. When one sequence in the N repeated frame synchronization sequences is captured, the system enters a tracking state, the system starts to respectively carry out serial matching filtering on the synchronization sequence and the reverse synchronization sequence, the size of the correlation peak value of the reverse synchronization sequence and the size of the correlation peak value of the original synchronization sequence are compared by utilizing the strong autocorrelation characteristic of the synchronization sequence, and when the difference between the two is larger than a fixed threshold, the frame synchronization is finished. The false alarm rate and the false alarm rate are balanced from two dimensions of the threshold and the frame format, and the reliability of frame synchronization judgment is improved by combining the self-adaptive threshold and the fixed threshold.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A frame synchronization decision device for deciding a frame synchronization sequence of a data frame, comprising: the device comprises an input cache module, a parallel matching filter, a relative threshold judgment module, an original synchronous sequence serial matching filter, an inverted sequence synchronous sequence serial matching filter, a correlation peak comparison module and an absolute threshold judgment module;
the input buffer module is used for receiving and buffering data frames and providing data sources to be correlated for the parallel matched filter;
the parallel matched filter is connected with the input cache module and is used for carrying out correlation operation on the cached data frame and the local pseudorandom sequence and outputting a correlation peak value as a parallel matched filtering result;
the relative threshold judgment module is connected with the parallel matched filter and is used for carrying out relative threshold judgment on the parallel output correlation peak values, when the relative threshold judgment quantity is larger than a preset threshold value, the serial number corresponding to the correlation peak value and the successfully-captured identification are output, otherwise, the unsuccessfully-captured identification is output;
the original synchronous sequence serial matching filter is connected with the relative threshold judging module and used for calculating the start bit of the effective data frame according to the time of successfully capturing the identification, performing related operation on the input data frame and the local pseudorandom sequence from the start bit and outputting a first serial matching filtering result;
the reverse sequence synchronous serial matched filter is connected with the relative threshold judging module and used for calculating the initial bit of the effective data frame according to the time of successfully capturing the identification, performing related operation on the input data frame and the reverse sequence form of the local pseudo-random sequence from the initial bit and outputting a second serial matched filtering result;
the correlation peak comparison module is respectively connected with the original synchronous sequence serial matched filter and the inverted synchronous sequence serial matched filter and is used for calculating and outputting a difference value between correlation peaks of the first serial matched filtering result in the original synchronous sequence serial matched filter and the second serial matched filtering result in the inverted synchronous sequence serial matched filter;
the absolute threshold decision module is respectively connected with the correlation peak comparison module, the original synchronization sequence serial matching filter and the reverse synchronization sequence serial matching filter and is used for making fixed threshold decision on the difference value obtained by the correlation peak module, outputting a synchronization completion identifier when the difference value is larger than a fixed threshold value, and otherwise, outputting a synchronization completion identifier;
the data head of the data frame comprises at least two repeated frame synchronization sequences and a reverse synchronization sequence.
2. The apparatus of claim 1, wherein the buffer size of the input buffer module is L × Q, L is the length of the received data header, and Q is an upsampling multiple of each symbol.
3. The frame synchronization decision device according to claim 1, wherein the parallel matched filter is configured to perform Q-fold extraction on the data frame in the input buffer module, perform parallel correlation with the local pseudorandom sequence in sequence, and output correlation peak values beat by beat.
4. The frame synchronization decision device according to claim 1, wherein the relative threshold decision module is configured to estimate a power value of an input data frame and divide the power value by a correlation peak value output by the parallel matched filter to obtain a relative threshold decision quantity; and when the relative threshold decision quantity is larger than the preset threshold value, outputting a serial number corresponding to the peak value, and simultaneously outputting the successfully-captured identifier, otherwise, outputting the unsuccessfully-captured identifier.
5. A frame synchronization decision method for deciding a frame synchronization sequence of a data frame, comprising:
receiving a data frame and caching the data frame;
performing parallel matched filtering on the data frame and a local pseudorandom sequence, and outputting a related peak value obtained by the parallel matched filtering as a parallel matched filtering result;
calculating relative threshold decision quantity of the parallel matched filtering result, and judging whether the relative threshold decision quantity is larger than a preset threshold value or not;
if so, outputting a serial number corresponding to the correlation peak value and a successfully-captured identifier, otherwise, outputting an unsuccessfully-captured identifier, and continuing to perform parallel matched filtering;
calculating the start bit of the effective data frame according to the time of the successfully captured identifier, and respectively performing serial matched filtering on the data frame and the reverse sequence of the local pseudorandom sequence from the start bit;
calculating and outputting a difference value between correlation peaks of results of the two serial matched filtering;
judging whether the difference value is larger than a preset fixed threshold value, if so, outputting a synchronization completion identifier, otherwise, outputting a synchronization incomplete identifier, and continuing to perform serial matching filtering;
the data head of the data frame comprises at least two repeated frame synchronization sequences and a reverse synchronization sequence.
6. The method for deciding frame synchronization according to claim 5, wherein the parallel matched filtering is performed on the data frame and the local pseudo-random sequence, and outputting a correlation peak obtained by the parallel matched filtering as a parallel matched filtering result specifically comprises:
down-sampling the data frame to make the sampling point rate consistent with the local pseudo-random sequence in the parallel matched filter;
multiplying the down-sampled data frames by corresponding local pseudo-random sequences respectively;
and respectively adding the multiplication results according to the real part and the imaginary part to obtain the correlation peak value of the parallel matched filtering.
7. The method for frame synchronization decision according to claim 5, wherein the calculating the relative threshold decision quantity of the parallel matched filter result, and the determining whether the relative threshold decision quantity is greater than the preset threshold value specifically includes:
accumulating and summing the input data frames with fixed length to be used as signal power estimation quantity;
calculating a quotient of the signal power estimator and a correlation peak of the parallel matched filtering result as a relative threshold decision quantity;
and calculating the difference between the relative threshold decision quantity and the preset threshold value, and judging whether the difference value is greater than zero.
8. The method for deciding frame synchronization according to claim 5, wherein the calculating a start bit of an effective data frame according to the time of the successful capturing identification, and performing serial matched filtering on the data frame and the reverse sequence of the local pseudo-random sequence and the local pseudo-random sequence from the start bit specifically comprises:
calculating the start bit of the effective data frame according to the time of successfully capturing the identification, performing serial matched filtering on the input data frame and the local pseudorandom sequence from the start bit, and outputting a first serial matched filtering result;
and calculating the start bit of the effective data frame according to the time of successfully capturing the identification, performing serial matched filtering on the input data frame and the reverse sequence form of the local pseudorandom sequence from the start bit, and outputting a second serial matched filtering result.
9. The frame synchronization decision method according to claim 5, wherein the buffered data frames are shifted in a first-in-first-out order.
10. The frame synchronization decision method of claim 7, wherein the fixed length of the input data frame is much larger than the length of the received data header.
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