CN108055106B - Recognition method for code word boundary based on RM code partial decoding auxiliary differential detection - Google Patents

Recognition method for code word boundary based on RM code partial decoding auxiliary differential detection Download PDF

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CN108055106B
CN108055106B CN201711313644.6A CN201711313644A CN108055106B CN 108055106 B CN108055106 B CN 108055106B CN 201711313644 A CN201711313644 A CN 201711313644A CN 108055106 B CN108055106 B CN 108055106B
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陈为刚
罗加兴
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Tianjin University
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Abstract

The invention discloses a code word boundary identification method based on RM code partial decoding auxiliary differential detection, which comprises the following steps: selecting a code bit sequence number pair in the code bit sequence according to the information bit, extracting data, carrying out conjugate multiplication, and summing the results of the conjugate multiplication to obtain a correlation value corresponding to the information bit; selecting a code bit serial number pair according to the information bit, extracting data to calculate intermediate information, and summing the intermediate information obtained by all code bit serial number pairs to obtain likelihood information corresponding to the information bit; taking the symbol of the likelihood information, multiplying the symbol by the correlation value and summing to obtain a final correlation value; and judging according to the final correlation value, if a code word boundary identification signal is output after judgment, triggering to output a code word boundary position reference signal and stopping code word boundary identification, and ending the process. The invention can quickly and accurately complete the code word boundary identification under the condition of low signal-to-noise ratio and carrier frequency deviation.

Description

Recognition method for code word boundary based on RM code partial decoding auxiliary differential detection
Technical Field
The invention relates to the technical field of digital communication transmission synchronization, in particular to a code word boundary identification method based on RM code partial decoding auxiliary differential detection.
Background
In a digital communication system, frame synchronization is a prerequisite for subsequent signal processing such as error correction, information extraction, and the like. In order to implement frame synchronization, there are two methods, one is to insert a synchronization sequence into a digital information stream as a start mark of each frame, and a receiving end can implement frame synchronization according to the position of the synchronization sequence, and the other is to implement frame synchronization by using the characteristics of encoded data without adding a synchronization sequence.
Two methods for inserting synchronization sequences to achieve frame synchronization are continuous insertion and interval insertion. The continuous insertion is to centrally insert the synchronization sequence at the beginning of each frame, and the interval insertion is to dispersedly insert the synchronization sequence into the data stream, i.e. to insert a certain number of synchronization symbols every certain number of information symbols. The receiving end detects the inserted synchronous sequence to realize frame synchronization. As the synchronization sequence of the frame synchronization mark, a local autocorrelation function with a sharp unimodal characteristic is provided, and therefore, the detection of the synchronization sequence is usually achieved by a correlation method. Correlation methods are simple to implement but have limited performance at low signal-to-noise ratios and poor performance in fading channels. Massey later proposed a synchronization algorithm for detecting synchronization sequences using the Maximum Likelihood (ML) rule for Additive White Gaussian Noise (AWGN) channels. The frame synchronization detection method based on the maximum likelihood obviously improves the system performance, but the ML estimator has high operation complexity. In order to reduce the complexity of implementation, various simplified estimators are also proposed, with a certain loss of performance, but with a greatly reduced complexity.
The method for realizing the frame synchronization by utilizing the characteristics of the coded data only depends on the coded data, thereby saving the system overhead. The scholars of Lorden et al propose a frame synchronization algorithm using a Viterbi decoder for convolutional codes, and use quantized data to calculate a syndrome pattern to determine whether to synchronize. Sun and Valenti have studied the maximum a posteriori frame synchronization algorithm suitable for Turbo coding system, judge the most probable frame starting position according to the parity check equation of Turbo code. As Low Density Parity Check (LDPC) codes are widely used, methods for implementing frame synchronization based on codeword characteristics of LDPC codes are widely studied. Wymeersch et al studied a maximum likelihood code-assisted frame synchronization method based on an expectation-maximization algorithm, which requires a complete iterative decoding process. Scholars such as Qi propose a frame synchronization algorithm based on a quasi-cyclic LDPC code, and compared with other LDPC decoding-assisted frame synchronization algorithms, the frame synchronization algorithm reduces hardware implementation complexity.
Disclosure of Invention
The invention provides a code word boundary identification method based on RM code partial decoding auxiliary differential detection, which can still quickly and accurately finish code word boundary identification under the conditions of low signal-to-noise ratio and carrier frequency deviation, and is described in detail as follows:
a method for detecting codeword boundary identification based on RM code partial decoding auxiliary differential, the method comprising the steps of:
1) selecting a code bit sequence number pair in the code bit sequence according to the information bit, extracting data, carrying out conjugate multiplication, and summing the results of the conjugate multiplication to obtain a correlation value corresponding to the information bit;
2) selecting a code bit serial number pair according to the information bit, extracting data to calculate intermediate information, and summing the intermediate information obtained by all code bit serial number pairs to obtain likelihood information corresponding to the information bit; taking the symbol of the likelihood information, multiplying the symbol by the correlation value and summing to obtain a final correlation value;
3) and judging according to the final correlation value, if a code word boundary identification signal is output after judgment, triggering to output a code word boundary position reference signal and stopping code word boundary identification, and ending the process.
Prior to step 1), the method further comprises the steps of:
a Reed-Muller code with the coding bit length of N is adopted at a sending end to bear information, and binary phase shift keying modulation symbol transmission is adopted after the Reed-Muller code is superposed with a pseudorandom sequence;
and sequentially shifting the received data into a shift register with the length of N at a receiving end, reading N data from the shift register, and multiplying the N data by N local symbols respectively to obtain N products, wherein the N local symbols are obtained by modulating N bits in the pseudorandom sequence through binary phase shift keying.
The sequence of the coded bit sequence number pair is specifically as follows:
constructing a coding bit length of N, an information bit length of K, and satisfying N-2K-1The sequence of coded bit number pairs corresponding to the information bits of the RM code.
The expression of the sequence of the coded bit sequence number pair is as follows:
Figure BDA0001503409300000021
wherein the coded bit sequence number pair
Figure BDA0001503409300000022
Satisfying the coded bits
Figure BDA0001503409300000023
Is constant, and
Figure BDA0001503409300000024
to be the number of the coded bits,
Figure BDA0001503409300000025
and is
Figure BDA0001503409300000026
Wherein i is 0,1, …, N/2-1, K is 0,1, …, K-2;
Figure BDA0001503409300000027
are all coded bits.
The summing the obtained intermediate information by all the code bit sequence numbers to obtain the likelihood information corresponding to the information bits specifically includes:
1) under the condition of no frequency offset: calculating a log-likelihood ratio, and calculating intermediate information according to the log-likelihood ratio;
2) in the case of frequency offset: calculating intermediate information according to the value of the data;
3) and summing the intermediate information obtained by calculating all the code bit sequence number pairs in the sequence according to the code bit sequence numbers, and outputting likelihood information.
Under the condition of no frequency deviation, the calculation of the intermediate information is realized by a minimum sum algorithm, an offset minimum sum algorithm and a table look-up method.
In the case of frequency offset: the calculation of the intermediate information according to the value of the data specifically comprises the following steps:
according to coded bit sequence number pair
Figure BDA0001503409300000031
Data in the extracted N products
Figure BDA0001503409300000032
Real part of
Figure BDA0001503409300000033
And imaginary part
Figure BDA0001503409300000034
And
Figure BDA0001503409300000035
real part of
Figure BDA0001503409300000036
And imaginary part
Figure BDA0001503409300000037
The calculation result is specifically as follows:
Figure BDA0001503409300000038
the technical scheme provided by the invention has the beneficial effects that:
(1) according to the encoding characteristic that two encoded bits of the RM code are subjected to XOR to be the same information bit, decoding of certain single bits under the condition of frequency offset is realized;
(2) according to the result of partial decoding, the uncertainty of information bits in the related value is eliminated, the speed of code word boundary identification is accelerated, and the code word boundary identification performance of the system working under the condition of low signal to noise ratio is obviously improved.
Drawings
FIG. 1 is a flow chart of a method for detecting codeword boundary identification based on RM code partial decoding aided differential;
FIG. 2 shows the construction of RM code information bits bkCorresponding coded bit number pair sequence TkA flow chart of (1);
fig. 3 is a block diagram of a transmission of modulation symbols using Binary Phase Shift Keying (BPSK);
FIG. 4 shows the acquisition of an information bit bkA corresponding correlation value block diagram;
FIG. 5 is a block diagram of an embodiment of partial correlation calculation;
FIG. 6 is a constellation diagram of a π/2 BPSK mapping scheme;
FIG. 7 is a diagram illustrating a graph of a change in a frame synchronization error rate with a signal-to-noise ratio representing a frame synchronization performance without a frequency offset;
fig. 8 is a graph illustrating a variation of a frame synchronization error rate with a signal-to-noise ratio, which represents a frame synchronization performance in the presence of a frequency offset.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention are described in further detail below.
In order to solve the problems existing in the background art, the embodiment of the invention provides a code word boundary identification method based on auxiliary differential detection of partial decoding of Reed-Muller (RM) codes, according to the condition that two encoded bits of the RM codes are subjected to exclusive OR to form the same information bit, and the sequence numbers of the two bits in a code word have the same interval, the decoding of certain single bits can be realized under the two conditions of no frequency offset and frequency offset. After decoding, the influence of information bit uncertainty on the related peak value is eliminated by using the result of partial decoding, and the performance of code word boundary identification is improved.
Example 1
The method is used in the realization of the physical layer frame synchronization part of a digital communication system receiver, partial decoding is carried out according to the coding characteristic that pairwise XOR of the coding bits of a first-order RM code is the same information bit, and the influence of the information bit in a related value is eliminated by using the result of the partial decoding, which is shown in figure 1, and the method comprises the following steps:
101: selecting a code bit sequence number pair in the code bit sequence according to the information bit, extracting data, carrying out conjugate multiplication, and summing the results of the conjugate multiplication to obtain a correlation value corresponding to the information bit;
102: selecting a code bit serial number pair according to the information bit, extracting data to calculate intermediate information, and summing the intermediate information obtained by all code bit serial number pairs to obtain likelihood information corresponding to the information bit; taking the symbol of the likelihood information, multiplying the symbol by the correlation value and summing to obtain a final correlation value;
103: and judging according to the final correlation value, if a code word boundary identification signal is output after judgment, triggering to output a code word boundary position reference signal and stopping code word boundary identification, and ending the process.
Further, before step 101, the method further comprises the steps of:
a Reed-Muller code with the coding bit length of N is adopted at a sending end to bear information, and binary phase shift keying modulation symbol transmission is adopted after the Reed-Muller code is superposed with a pseudorandom sequence;
and sequentially shifting the received data into a shift register with the length of N at a receiving end, reading N data from the shift register, and multiplying the N data by N local symbols respectively to obtain N products, wherein the N local symbols are obtained by modulating N bits in the pseudorandom sequence through binary phase shift keying.
In summary, the embodiments of the present invention implement, through the above steps, partial decoding of the RM code according to the characteristic that the encoded bits of the RM code are xored pairwise to form the same information bit, and then eliminate the influence of the information bit in the correlation value according to the result of the partial decoding, thereby improving the performance of codeword boundary identification.
Example 2
The scheme of example 1 is further described below with reference to specific calculation formulas and fig. 1, and is described in detail below:
201: constructing a coding bit length of N, an information bit length of K, and satisfying N-2K-1Information bit b of Reed-Muller (RM) codekCorresponding coded bit number pair sequence Tk；
202: an RM (N, K) code is adopted at a transmitting end to bear information, and Binary Phase Shift Keying (BPSK) modulation symbols are adopted for transmission after the RM (N, K) code is superposed with a pseudorandom sequence s;
in BPSK, bit '0' is mapped to symbol '+ 1', and bit '1' is mapped to symbol '-1'.
203: sequentially shifting the received data into a shift register with the length of N at a receiving end, shifting one bit each time until the data are shifted into the N shift registers, and shifting the data r in the N registers into the N shift registersnWith local symbols dnMultiplying to obtain the product
Figure BDA0001503409300000051
Wherein d isnFor the nth bit s of snBPSK modulated symbol, where N is 0,1, …, N-1.
204: according to the information bit bkSelecting pairs of coded bit sequence numbers
Figure BDA0001503409300000052
Extracting data
Figure BDA0001503409300000053
And
Figure BDA0001503409300000054
conjugate multiplication is carried out, and then the result after the conjugate multiplication is summed to obtain the information bit bkCorresponding correlation value Λk；
205: according to the information bit bkSelecting pairs of coded bit sequence numbers
Figure BDA0001503409300000055
Extracting data
Figure BDA0001503409300000056
And
Figure BDA0001503409300000057
computing intermediate information
Figure BDA00015034093000000523
And will be based on all coded bit sequence number pairs
Figure BDA0001503409300000058
Obtained by
Figure BDA0001503409300000059
Summing to obtain information bit bkCorresponding likelihood information Lk；
206: likelihood information L is takenkThen correlate it with a correlation value ΛkMultiplying and summing to obtain a final correlation value Λ;
207: and judging according to the final correlation value lambda, if a code word boundary identification signal is output after judgment, triggering to output a code word boundary position reference signal and stopping code word boundary identification, ending the process, and otherwise, returning to the step 203.
In summary, the embodiment of the present invention, through the above step 201-.
Example 3
The following detailed description will be made with reference to specific calculation formulas and fig. 2-5 for the specific operation steps of 201 and 206 in examples 1 and 2, and the following description refers to the following:
301: constructing a sequence T of pairs of encoded bit sequence numbersk；
As shown in fig. 2, the steps specifically include:
1) the initialization i is 0 and the initialization is,
Figure BDA00015034093000000510
j＝1；
2) calculating serial numbers
Figure BDA00015034093000000511
And let i ═ i + 1;
3) if j < 2kIf j is j +1,
Figure BDA00015034093000000512
and executing step 2), otherwise executing step 4);
4) if it is
Figure BDA00015034093000000513
Then j is equal to 1 and,
Figure BDA00015034093000000514
and executing step (2), otherwise, outputting a coded bit sequence number pair sequence Tk。
Wherein, the sequence T of the coded bit sequence number pairkThe expression of (a) is:
Figure BDA00015034093000000515
Tkmiddle coded bit sequence number pair
Figure BDA00015034093000000516
Satisfying the coded bits
Figure BDA00015034093000000517
Is constant, and
Figure BDA00015034093000000518
Figure BDA00015034093000000519
to be the number of the coded bits,
Figure BDA00015034093000000520
and is
Figure BDA00015034093000000521
Wherein i is 0,1, …, N/2-1, K is 0,1, …, K-2;
Figure BDA00015034093000000522
are all coded bits.
302: binary Phase Shift Keying (BPSK) modulation symbol transmission is adopted;
as shown in fig. 3, this embodiment is:
1) encoding the K information bits by RM (N, K) codes to obtain N encoding bits;
2) carrying out exclusive or on the N coded bits and a pseudorandom sequence with the length of N;
3) and mapping and transmitting the N bits after the XOR is completed in a BPSK mapping mode.
303: data r in N registersnWith local symbols dnMultiplying to obtain the product
Figure BDA0001503409300000061
As shown in fig. 4, the steps specifically include:
Figure BDA0001503409300000062
304: summing the results of conjugate multiplication to obtain information bit bkCorresponding correlation value Λk；
As shown in fig. 5, the steps specifically include:
Figure BDA0001503409300000063
305: all coded bit sequence number pairs
Figure BDA0001503409300000064
Obtained by
Figure BDA0001503409300000065
Summing to obtain information bit bkCorresponding likelihood information Lk；
As shown in fig. 5, the steps specifically include:
1) without frequency offset, first based on the data
Figure BDA0001503409300000066
And
Figure BDA0001503409300000067
separately calculating log-likelihood ratios
Figure BDA0001503409300000068
And
Figure BDA0001503409300000069
the log-likelihood ratio is the logarithm of the ratio of the probability of 0 to the probability of 1 for the corresponding bit of data, and is then based on
Figure BDA00015034093000000610
And
Figure BDA00015034093000000611
computing intermediate information
Figure BDA00015034093000000612
Figure BDA00015034093000000613
In the formula,
Figure BDA00015034093000000614
intermediate information
Figure BDA00015034093000000615
The calculation of (2) can also be realized by a minimum sum algorithm, an offset minimum sum algorithm and a table look-up method, wherein the minimum sum algorithm specifically comprises the following steps:
Figure BDA00015034093000000616
wherein sgn (·) is a sign-taking function, and the offset minimum sum algorithm specifically includes:
Figure BDA00015034093000000617
wherein, the beta is an offset factor which can be obtained by a density evolution and computer simulation method, and the table look-up method specifically comprises the following steps:
Figure BDA00015034093000000618
wherein LUT (a, b) is log (1+ e)-|a+b|)-log(1+e-|a-b|) This can be done by building a look-up table.
The above-mentioned minimum sum algorithm, offset minimum sum algorithm and table lookup method are well known to those skilled in the art, and are not described in detail in the embodiments of the present invention.
2) In the presence of frequency deviation, according to
Figure BDA0001503409300000071
And
Figure BDA0001503409300000072
computing intermediate information of
Figure BDA0001503409300000073
Figure BDA0001503409300000074
In the formula,
Figure BDA0001503409300000075
and
Figure BDA0001503409300000076
are respectively data
Figure BDA0001503409300000077
The real and imaginary parts of (a) and (b),
Figure BDA0001503409300000078
and
Figure BDA0001503409300000079
are respectively data
Figure BDA00015034093000000710
Real and imaginary parts of (c).
3) According to TkIntermediate information obtained by calculating all coded bit sequence number pairs
Figure BDA00015034093000000711
Sum, output bkLikelihood information LkComprises the following steps:
Figure BDA00015034093000000712
306: likelihood information L is takenkThen correlate it with a correlation value ΛkMultiplied and summed to obtain the final correlation value Λ.
As shown in fig. 4 and 5, the steps specifically include:
Figure BDA00015034093000000713
in summary, the embodiments of the present invention implement, through the above steps, partial decoding of the RM code according to the characteristic that the encoded bits of the RM code are xored pairwise to form the same information bit, and then eliminate the influence of the information bit in the correlation value according to the result of the partial decoding, thereby improving the performance of codeword boundary identification.
Example 4
The feasibility of the schemes of examples 1-3 is verified by combining the specific examples, calculation formulas and fig. 6-8, as described in detail below:
in the DVB-S2 system, Frame synchronization is achieved by detecting a physical layer header in a data Frame, where the physical layer header includes a Start of Frame (SOF) and a physical layer signaling encoding portion encoded with RM (64, 7). For SOF field, calculating correlation value of SOF field by differential detection, and for physical layer signaling coding part adopting the scheme designed by the method. Under AWGN channel, when the condition of no frequency offset and the normalized frequency offset in DVB-S2 system are simulated and analyzed to be 0.01, the scheme designed by the method and the frame synchronization scheme of differential detection and multiple correlation peak detection have the frame synchronization performance under the condition of no frequency offset and frequency offset.
Frame synchronization firstly shifts the received data into a shift register with the length of 90 in sequence, one bit of data is shifted in each time until the data is shifted in 90 shift registers, then the data in the first 26 registers corresponding to the SOF field are differentially correlated, and the correlation value Λ is outputSOFThe method specifically comprises the following steps:
Figure BDA00015034093000000714
in the formula, ri-1And riFor the ith-1 and ith data in the first 26 registers,
Figure BDA00015034093000000715
is the i-1 th correlation coefficient, wherein i is 1,2, …, 25. Wherein the 25-bit correlation coefficients are:
1,1,1,1,-1,-1,-1,-1,1,-1,-1,-1,1,-1,-1,1,-1,1,1,1,-1,1,-1,-1,1
and finally, calculating the related values of the data in the last 64 registers corresponding to the physical layer signaling coding field according to the scheme designed by the method, wherein the specific steps are as follows:
constructing RM (64,7) code information bit bkCorresponding coded bit number pair sequence TkAs shown in table 1.
TABLE 1 information bit bkAnd corresponding sequence of pairs of code bit sequence numbers Tk
Figure BDA0001503409300000081
Physical layer signaling information of DVB-S2 is carried by RM (64,7) code at transmitting end, and is superposed with pseudo-random sequence
Figure BDA0001503409300000082
The pseudo random sequence for BPSK modulation symbol transmission specifically includes:
0,1,1,1,0,0,0,1,1,0,0,1,1,1,0,1,1,0,0,0,0,0,1,1,1,1,0,0,1,0,0,1,
0,1,0,1,0,0,1,1,0,1,0,0,0,0,1,0,0,0,1,0,1,1,0,1,1,1,1,1,1,0,1,0
wherein,
Figure BDA0001503409300000083
the constellation diagram of the BPSK modulation scheme is shown in fig. 6, and the specific calculation formula is:
Figure BDA0001503409300000091
where m is 0,1, …,31, y is bits before data mapping, and z is a symbol after mapping.
Data r in 64 registersnAnd local coefficient dnMultiplication to obtain
Figure BDA0001503409300000092
Local coefficient dnThe method specifically comprises the following steps:
1,-1,-1,-1,1,1,1,-1,-1,1,1,-1,-1,-1,1,-1,-1,1,1,1,1,1,-1,-1,-1,-1,1,1,-1,1,1,-1,
1,-1,1,-1,1,1,-1,-1,1,-1,1,1,1,1,-1,1,1,1,-1,1,-1,-1,1,-1,-1,-1,-1,-1,-1,1,-1,1
according to the information bit bkSelecting a sequence T of pairs of coded bit sequence numberskCoded bit sequence number pair of
Figure BDA0001503409300000093
Extracting data
Figure BDA0001503409300000094
And
Figure BDA0001503409300000095
conjugate multiplication is carried out, and then the results after the conjugate multiplication are summed to obtain bkCorresponding correlation value ΛkWhere i is 0,1, …,31, specifically:
Figure BDA0001503409300000096
1) without frequency offset, first based on the data
Figure BDA0001503409300000097
And
Figure BDA0001503409300000098
calculating log-likelihood ratios
Figure BDA0001503409300000099
And
Figure BDA00015034093000000910
then according to
Figure BDA00015034093000000911
And
Figure BDA00015034093000000912
computing intermediate information
Figure BDA00015034093000000913
Figure BDA00015034093000000914
The physical layer header part in the DVB-S2 system is adopted
Figure BDA00015034093000000915
In the BPSK modulation scheme, the calculation formula of the log likelihood ratio is:
Figure BDA00015034093000000916
wherein the LLRjRepresents the j-th data
Figure BDA00015034093000000917
The corresponding log-likelihood ratio is then determined,
Figure BDA00015034093000000918
and
Figure BDA00015034093000000919
as data
Figure BDA00015034093000000920
Real and imaginary parts of (c).
2) In case of frequency offset, according to the second 64 registers
Figure BDA00015034093000000921
And
Figure BDA00015034093000000922
data calculation intermediate information in individual registers
Figure BDA00015034093000000923
Figure BDA00015034093000000924
3) Will be according to TkIntermediate information obtained by calculating all coded bit sequence number pairs
Figure BDA00015034093000000925
Sum, output bkLikelihood information LkComprises the following steps:
Figure BDA00015034093000000926
likelihood information L is takenkThen correlate it with a correlation value ΛkMultiplying and summing, summing and ΛSOFAdding and sending the signals to a peak value detection module, specifically:
Figure BDA00015034093000000927
the simulation results are shown in fig. 7 and 8. The result shows that the Frame Synchronization Error Rate (FSER) of the method is lower than that of the Frame Synchronization scheme of differential detection and multiple correlation peak detection under the same signal-to-noise ratio.
Those skilled in the art will appreciate that the drawings are only schematic illustrations of preferred embodiments, and the above-described embodiments of the present invention are merely provided for description and do not represent the merits of the embodiments.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims (4)

1. An RM code based code partial decoding assisted differential detection code word boundary identification method is characterized by comprising the following steps:
1) selecting a code bit sequence number pair in the code bit sequence according to the information bit, extracting data, carrying out conjugate multiplication, and summing the results of the conjugate multiplication to obtain a correlation value corresponding to the information bit;
2) selecting a code bit serial number pair according to the information bit, extracting data to calculate intermediate information, and summing the intermediate information obtained by all code bit serial number pairs to obtain likelihood information corresponding to the information bit; taking the symbol of the likelihood information, multiplying the symbol by the correlation value and summing to obtain a final correlation value;
3) judging according to the final correlation value, if a code word boundary identification signal is output after judgment, triggering to output a code word boundary position reference signal and stopping code word boundary identification, and ending the process;
wherein, selecting the code bit sequence number pair according to the information bits, extracting data and calculating the intermediate information specifically comprises:
under the condition of no frequency offset: calculating a log-likelihood ratio, and calculating intermediate information through a minimum sum algorithm or an offset minimum sum algorithm or a table look-up method according to the log-likelihood ratio;
in the case of frequency offset: according to coded bit sequence number pair
Figure FDA0002477289890000011
Data in the extracted N products
Figure FDA0002477289890000012
Real part of
Figure FDA0002477289890000013
And imaginary part
Figure FDA0002477289890000014
And
Figure FDA0002477289890000015
real part of
Figure FDA0002477289890000016
And imaginary part
Figure FDA0002477289890000017
The calculation result is specifically as follows:
Figure FDA0002477289890000018
2. the method for identifying codeword boundaries based on RM code partial decoding aided differential detection as claimed in claim 1, wherein before step 1), the method further comprises the steps of:
a Reed-Muller code with the coding bit length of N is adopted at a sending end to bear information, and binary phase shift keying modulation symbol transmission is adopted after the Reed-Muller code is superposed with a pseudorandom sequence;
and sequentially shifting the received data into a shift register with the length of N at a receiving end, reading N data from the shift register, and multiplying the N data by N local symbols respectively to obtain N products, wherein the N local symbols are obtained by modulating N bits in the pseudorandom sequence through binary phase shift keying.
3. The method as claimed in claim 1, wherein the sequence of coded bit sequence number pairs is specifically:
constructing a coding bit length of N, an information bit length of K, and satisfying N-2K-1The sequence of coded bit number pairs corresponding to the information bits of the RM code.
4. The method as claimed in claim 1 or 3, wherein the expression of the sequence of coded bit sequence number pairs is:
Figure FDA0002477289890000021
wherein the coded bit sequence number pair
Figure FDA0002477289890000022
Satisfying the coded bits
Figure FDA0002477289890000023
Is constant, and
Figure FDA0002477289890000024
Figure FDA0002477289890000025
to code the number of bits，
Figure 1
And is
Figure FDA0002477289890000027
Wherein i is 0,1, …, N/2-1, K is 0,1, …, K-2;
Figure FDA0002477289890000028
are all coded bits.
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0935362A2 (en) * 1998-02-06 1999-08-11 Alcatel Synchronisation device for a synchronous digital transmission system and method for generating a synchronous output signal
CN102420617A (en) * 2011-11-14 2012-04-18 中兴通讯股份有限公司 Overlapped RM (Reed-Muller) code decoding method and system
CN103414674A (en) * 2013-07-18 2013-11-27 西安空间无线电技术研究所 MAPSK self-adaptive demodulating system
CN106788887A (en) * 2016-12-09 2017-05-31 天津大学 A kind of soft decoding method received based on multi-path distributed transparent hard decision

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0935362A2 (en) * 1998-02-06 1999-08-11 Alcatel Synchronisation device for a synchronous digital transmission system and method for generating a synchronous output signal
CN102420617A (en) * 2011-11-14 2012-04-18 中兴通讯股份有限公司 Overlapped RM (Reed-Muller) code decoding method and system
CN103414674A (en) * 2013-07-18 2013-11-27 西安空间无线电技术研究所 MAPSK self-adaptive demodulating system
CN106788887A (en) * 2016-12-09 2017-05-31 天津大学 A kind of soft decoding method received based on multi-path distributed transparent hard decision

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Efficient Maximum-Likelihood Decoding of -ary Modulated Reed–Muller Codes;Alexander J. Grant, Member, IEEE, and Richard D. van Nee, Member;《IEEE COMMUNICATIONS LETTERS》;19980531;第2卷(第5期);全文 *

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