TCM code parameter blind identification method and device and storage medium

Abstract

The invention discloses a TCM code parameter blind identification method and device and a storage medium, and belongs to the field of electronic signal reconnaissance and confrontation. The method comprises the following steps: S1, acquiring binary code stream data, an initial code length and an initial constraint length of TCM coding; s2, constructing a binary linear equation set, and obtaining a mapping vector; s3, segmenting the mapping vector, and then constructing a Hadamard matrix; s4, carrying out Walsh-Hadamard transformation on the segmented vectors, so as to obtain a value of a Walsh spectrum; s5, searching a Walsh spectrum peak value outside the 0 point position, if the Walsh spectrum peak value is searched, obtaining a correct code length and a correct constraint length according to the position of the Walsh spectrum peak, and executing S6; if the Walsh spectrum peak value is not found, adding 1 to the initial code length, returning to S2, and continuing to execute the subsequent steps; and S6, constructing a new binary linear equation set, performing Walsh-Hadamard transformation according to the correct code length and the correct constraint length to obtain a correct initial position and a correct check matrix, and outputting an identification result. The method is low in calculation complexity, easy in engineering implementation and high in operation speed.

Description

Technical Field

[0001] The present invention relates to the field of electronic signal reconnaissance and countermeasure, and in particular to a TCM code parameter blind recognition method, device and storage medium. Background Art

[0002] In digital communication systems, various interference and noise conditions exist in the channel, leading to information errors during transmission. Channel coding techniques are often employed to ensure transmission reliability and minimize the impact of errors on accurate information. In the fields of non-cooperative electronic reconnaissance and electronic countermeasures, correctly identifying the channel coding type and its encoding parameters from intercepted information streams, thereby enabling correct decoding, is crucial for transitioning from the signal layer to the information layer. In these fields, non-standard encoding parameters are often employed to ensure system security, preventing the recipient from providing additional information beyond the intercepted information. However, in order to recover the original information from the intercepted signal, the recipient must identify the signal's encoding parameters without prior knowledge of the encoding.

[0003] Trellis Coded Modulation (TCM) is a spatial coding of signal sets and a highly efficient communications technology that combines error-correction coding with modulation techniques. TCM coding improves noise immunity by increasing the Euclidean distance between symbols while maintaining bandwidth and power efficiency. Therefore, it is widely used in telephone modem, Wi-Fi, cellular communications, satellite communications, broadcasting, and other fields. Accurately identifying the coding parameters of TCM codes in various fields, particularly blindly identifying these parameters and recovering the original information from intercepted signals, is crucial in electronic countermeasures, electronic reconnaissance, and radio signal detection. Existing methods for blindly identifying TCM code parameters are computationally complex, slow, and difficult to implement in engineering. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method, device and storage medium for blind identification of TCM code parameters.

[0005] The object of the present invention is achieved through the following technical solutions: In a first aspect, the present invention provides: a TCM code parameter blind recognition method, comprising the following steps: S1: Obtain TCM-coded binary code stream data, initial code length, and initial constraint length; S2: Construct a set of two-variable linear equations and obtain the mapping vector; S3: Segment the mapping vector and then construct the Hadamard matrix; S4: Perform Walsh-Hadamard transformation on the segmented vector to obtain the value of the Walsh spectrum; S5: Search for a Walsh spectrum peak outside the zero point position. If a Walsh spectrum peak is found, the correct code length and constraint length are obtained based on the position of the Walsh spectrum peak, and S6 is executed. If no Walsh spectrum peak is found, the initial code length is increased by 1, and the process returns to S2 and continues with the subsequent steps. S6: Construct a new binary linear equation system, perform Walsh-Hadamard transform based on the correct code length and correct constraint length, obtain the correct starting position and check matrix, and output the recognition result.

[0006] Preferably, the S1 further comprises the following steps: The TCM-encoded binary code stream data is segmented according to 2^n and traversed within the code length range to form a truncated sequence C2, where n=1, 2...12; the code length range is 3, 4, 5.

[0007] Preferably, the S2 further comprises the following steps: According to the length of the truncated sequence C2, a binary linear equation system is constructed, and the row coefficients of the binary linear equation system are mapped to decimal data to obtain a mapping vector V.

[0008] Preferably, the step S3 further comprises the following steps: The mapping vector V is segmented to construct a new vector V2 with a column width of col2 and a row width of row2. The Hadamard matrix is ​​constructed based on the column width col2.

[0009] Preferably, the Walsh spectrum peak is searched according to a threshold value.

[0010] Preferably, the step S6 further comprises the following steps: The starting position function is traversed according to the correct code length and the correct constraint length, and then the binary code stream data is truncated to form a new truncation sequence C3; A new binary linear equation system is constructed based on the truncated sequence C3, and then a Walsh-Hadamard transform is performed. The correct starting position and check matrix are determined based on the Walsh spectrum peak. Finally, according to the properties of TCM coding, the corresponding generator matrix is ​​obtained, and the correct code length, constraint length, starting position and check matrix are output as the recognition result.

[0011] Preferably, the code stream sequence of the binary code stream data is y (j), where the value range of j is j=1,2,3…M; M is the buffer length of the code stream sequence, and its value is an integer multiple of 2^n.

[0012] A second aspect of the present invention provides: a TCM code parameter blind recognition device, used to implement any of the above-mentioned TCM code parameter blind recognition methods, comprising: A data acquisition module is used to obtain TCM-coded binary code stream data, initial code length, and initial constraint length; A binary equation group construction module is used to construct the required binary linear equation group according to the binary code stream data, the initial code length and the initial constraint length, and transform the binary linear equation group to obtain a mapping vector; Walsh-Hadamard transform module, used to identify the correct code length and constraint length based on the mapping vector using Walsh-Hadamard transform; The TCM code parameter identification module is used to traverse the starting position based on the correct code length and constraint length, construct a new set of binary linear equations, and use the Walsh spectrum peak to determine the correct starting position and check matrix. Ultimately, it completes the identification of the correct code length, constraint length, starting position, and check matrix of the TCM code.

[0013] The third aspect of the present invention provides: a computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are loaded and executed by a processor, any of the above-mentioned TCM code parameter blind recognition methods is implemented.

[0014] The beneficial effects of the present invention are: 1) Using segmented processing, the problem of solving high-dimensional equations by Walsh-Hadamard transform is decomposed into the problem of solving two lower-dimensional equations, which reduces the computational complexity from an exponential complexity to Becomes complexity The reduction in complexity also makes this method easy to implement and have fast computing speed.

[0015] 2) This method can blindly identify TCM code parameters without knowing any parameters. By constructing a binary domain linear equation system and solving it using a piecewise Walsh-Hadamard transform, it can obtain the code length and constraint length of the TCM code. Then, based on the correct parameters, a new binary domain linear equation system is constructed and solved to obtain the code length, starting position, constraint length, and check matrix. In non-cooperative communication, the identified parameters can be used to decode the information and recover the original message. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Flowchart of the TCM code parameter blind recognition method; Figure 2 This is the principle block diagram of the TCM code parameter blind recognition device; Figure 3 It is a segmented schematic diagram of the vectors corresponding to the coefficients of the system of equations of the present invention. DETAILED DESCRIPTION

[0017] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work shall fall within the scope of protection of the present invention.

[0018] See Figure 1-Figure 3 The first aspect of the present invention provides: a TCM code parameter blind identification method, comprising the following steps: S1: Obtain TCM-coded binary code stream data, initial code length, and initial constraint length; S2: Construct a set of two-variable linear equations and obtain the mapping vector; S3: Segment the mapping vector and then construct the Hadamard matrix; S4: Perform Walsh-Hadamard transformation on the segmented vector to obtain the value of the Walsh spectrum; S5: Search for a Walsh spectrum peak outside the zero point position. If a Walsh spectrum peak is found, the correct code length and constraint length are obtained based on the position of the Walsh spectrum peak, and S6 is executed. If no Walsh spectrum peak is found, the initial code length is increased by 1, and the process returns to S2 and continues with the subsequent steps. S6: Construct a new binary linear equation system, perform Walsh-Hadamard transform based on the correct code length and correct constraint length, obtain the correct starting position and check matrix, and output the recognition result.

[0019] In some embodiments, the S1 further comprises the following steps: The TCM-encoded binary code stream data is segmented according to 2^n and traversed within the code length range to form a truncated sequence C2, where n=1, 2...12; the code length range is 3, 4, 5.

[0020] In some embodiments, the S2 further comprises the following steps: According to the length of the truncated sequence C2, a binary linear equation system is constructed, and the row coefficients of the binary linear equation system are mapped to decimal data to obtain a mapping vector V.

[0021] In this embodiment, the process of mapping the row coefficients of the binary linear equations into decimal data is as follows: First, assume that The construction length is Vector , the construction method is to convert the vector corresponding to the decimal number The position in is set to m ( m is the number of times this decimal number appears, and also the number of times this code word appears), and the rest are set to 0. For example =10, then Set it to 1, and the rest to 0.

[0022] ; Assume that there is N There are two linear equations in two variables, then the vector corresponding to the coefficient matrix of the equation system is V for: ; In some embodiments, the S3 further comprises the following steps: The mapping vector V is segmented to construct a new vector V2 with a column width of col2 and a row width of row2. The Hadamard matrix is ​​constructed based on the column width col2.

[0023] In this embodiment, if Figure 3 As shown, the mapping vector V is a × The matrix of dimension, after segmentation, forms a vector V2 The Hadamard matrix is ​​to divide the mapping vector V corresponding to the coefficients of the equation into segments V2, and then construct an m-dimensional Hadamard matrix according to the column width of V2, where m = col2+1. Then the Hadamard matrix can be expressed as: ; The construction is .

[0024] In step S4, it is assumed that is the Walsh spectrum expression of vector V2, then the Walsh-Hadamard transform can be expressed as: Furthermore, by segmenting the vector V, the problem of solving the high-dimensional equations by the Walsh-Hadamard transform is decomposed into the problem of solving two lower-dimensional equations. N The Walsh transform is essentially a matrix multiplication, and its direct computational complexity is , is an exponential complexity. If calculated directly, N When it is large, it often exceeds the computer memory. Considering that the form of Walsh transform is similar to Fourier transform, a fast Walsh transform algorithm can be used by using the principle of butterfly operation to reduce the computational complexity to .

[0025] remember , then ,then: ; Rearranging the two parts of the above formula into two rows gives: ; Further: ; By recursively following this method, the Walsh transform can be completed after segmenting the data in V, thus avoiding the extensive computation required by the Hadamard matrix. The fast Walsh-Hadamard transform significantly reduces computational complexity, saving storage space and register usage, and is beneficial for practical applications.

[0026] In step S5, after the correct code length and the correct constraint length are identified according to the peak search method, a peak will appear in the Walsh spectrum of V2 except for the 0 point position. The value of this peak position is converted into a binary vector ,but is the check vector. If both the code length and constraint length are incorrect, the Walsh spectrum will have a peak only at position 0, with no peaks elsewhere. In this case, the initial code length is increased by 1, and S2 and subsequent steps are continued. If the code length exceeds 5, the loop is exited and an error is reported.

[0027] In some embodiments, the Walsh spectrum peak is found according to a threshold value.

[0028] In some embodiments, the S6 further includes the following steps: The starting position function is traversed according to the correct code length and the correct constraint length, and then the binary code stream data is truncated to form a new truncation sequence C3; A new binary linear equation system is constructed based on the truncated sequence C3, and then a Walsh-Hadamard transform is performed. The correct starting position and check matrix are determined based on the Walsh spectrum peak. Finally, according to the properties of TCM coding, the corresponding generator matrix is ​​obtained, and the correct code length, constraint length, starting position and check matrix are output as the recognition result.

[0029] In this embodiment, C3 is constructed as follows: ; A row in the coefficient matrix is ​​denoted by its length Vector y i , yi To truncate a certain segment of data in sequence C2.

[0030] In some embodiments, the code stream sequence of the binary code stream data is y (j), where the value range of j is j=1,2,3…M; M is the buffer length of the code stream sequence, and its value is an integer multiple of 2^n.

[0031] A second aspect of the present invention provides: a TCM code parameter blind recognition device, used to implement any of the above-mentioned TCM code parameter blind recognition methods, comprising: A data acquisition module is used to obtain TCM-coded binary code stream data, initial code length, and initial constraint length; A binary equation group construction module is used to construct the required binary linear equation group according to the binary code stream data, the initial code length and the initial constraint length, and transform the binary linear equation group to obtain a mapping vector; Walsh-Hadamard transform module, used to identify the correct code length and constraint length based on the mapping vector using Walsh-Hadamard transform; The TCM code parameter identification module is used to traverse the starting position based on the correct code length and constraint length, construct a new set of binary linear equations, and use the Walsh spectrum peak to determine the correct starting position and check matrix. Ultimately, it completes the identification of the correct code length, constraint length, starting position, and check matrix of the TCM code.

[0032] The third aspect of the present invention provides: a computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are loaded and executed by a processor, any of the above-mentioned TCM code parameter blind recognition methods is implemented.

[0033] The foregoing description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein and should not be construed as excluding other embodiments. Rather, the present invention can be used in various other combinations, modifications, and environments and can be modified within the scope of the concept described herein through the above teachings or techniques or knowledge in the relevant field. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention are intended to be protected by the appended claims.

Claims

1. A TCM code parameter blind identification method, characterized by: The following steps are involved: S1: Obtain TCM-coded binary code stream data, initial code length, and initial constraint length; S2: Construct a set of two-variable linear equations and obtain the mapping vector; S3: Segment the mapping vector and then construct the Hadamard matrix; S4: Perform Walsh-Hadamard transformation on the segmented vector to obtain the value of the Walsh spectrum; S5: Search for a Walsh spectrum peak outside the zero point position. If a Walsh spectrum peak is found, the correct code length and constraint length are obtained based on the position of the Walsh spectrum peak, and S6 is executed. If no Walsh spectrum peak is found, the initial code length is increased by 1, and the process returns to S2 and continues with the subsequent steps. S6: Construct a new binary linear equation system, perform Walsh-Hadamard transform based on the correct code length and correct constraint length, obtain the correct starting position and check matrix, and output the recognition result.

2. The TCM code parameter blind identification method according to claim 1, wherein: The S1 further comprises the following steps: The TCM-encoded binary code stream data is segmented according to 2^n and traversed within the code length range to form a truncated sequence C2, where n=1, 2...12; the code length range is 3, 4, 5.

3. The TCM code parameter blind recognition method according to claim 2, wherein: The S2 further comprises the following steps: According to the length of the truncated sequence C2, a binary linear equation system is constructed, and the row coefficients of the binary linear equation system are mapped to decimal data to obtain a mapping vector V.

4. The TCM code parameter blind recognition method according to claim 3, wherein: The S3 further comprises the following steps: The mapping vector V is segmented to construct a new vector V2 with a column width of col2 and a row width of row2. The Hadamard matrix is ​​constructed based on the column width col2.

5. The TCM code parameter blind recognition method according to claim 1, wherein: Find the Walsh spectrum peak according to the threshold value.

6. The TCM code parameter blind identification method according to claim 1, wherein: The S6 further comprises the following steps: The starting position function is traversed according to the correct code length and the correct constraint length, and then the binary code stream data is truncated to form a new truncation sequence C3; A new binary linear equation system is constructed based on the truncated sequence C3, and then a Walsh-Hadamard transform is performed. The correct starting position and check matrix are determined based on the Walsh spectrum peak. Finally, according to the properties of TCM coding, the corresponding generator matrix is ​​obtained, and the correct code length, constraint length, starting position and check matrix are output as the recognition result.

7. The TCM code parameter blind recognition method according to claim 2, wherein: The code stream sequence of the binary code stream data is y (j), where the value range of j is j=1,2,3…M; M is the buffer length of the code stream sequence, and its value is an integer multiple of 2^n.

8. A TCM code parameter blind recognition device, characterized by: The method for blindly identifying TCM code parameters according to any one of claims 1 to 7 comprises: A data acquisition module is used to obtain TCM-coded binary code stream data, initial code length, and initial constraint length; A binary equation group construction module is used to construct the required binary linear equation group according to the binary code stream data, the initial code length and the initial constraint length, and transform the binary linear equation group to obtain a mapping vector; Walsh-Hadamard transform module, used to identify the correct code length and constraint length based on the mapping vector using Walsh-Hadamard transform; The TCM code parameter identification module is used to traverse the starting position based on the correct code length and constraint length, construct a new set of binary linear equations, and use the Walsh spectrum peak to determine the correct starting position and check matrix. Ultimately, it completes the identification of the correct code length, constraint length, starting position, and check matrix of the TCM code.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions. When the computer-executable instructions are loaded and executed by the processor, the TCM code parameter blind recognition method according to any one of claims 1 to 7 is implemented.

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