A signal transmission method, a transmission end, a receiving method and a receiving end based on constellation flattening encoding

Abstract

The application discloses a signal transmission method based on constellation flattening coding in the technical field of magnetic communication, a transmission end, a receiving method and a receiving end, and comprises the following steps: obtaining a secret key initial value, solving a chaotic sequence, and obtaining scrambled data by performing XOR scrambling on the chaotic sequence; performing binary conversion on the secret key initial value to obtain a binary key, and constructing multiple index information according to the binary key; performing three-dimensional constellation mapping on the scrambled data to obtain three-dimensional constellation position data, then obtaining three-dimensional constellation position data including a silent subcarrier; performing flattening processing to obtain two-dimensional constellation position data; performing masking to obtain encrypted data, and transmitting the encrypted data. The application realizes the compression of constellation dimensions through flattening coding, maximizes the minimum Euclidean distance between constellation points under limited transmission power, and further improves the security of magnetic induction communication by using the masking of the flattening coding rule.

Description

Technical Field

[0001] This invention relates to a signal transmission method, a transmitting end, a receiving method, and a receiving end based on constellation flat coding, belonging to the field of magnetic communication technology. Background Technology

[0002] The ocean, as the cradle of life on Earth, is a vital space for human survival and sustainable development, attracting numerous scholars to study and explore it. The information capacity requirements of various devices and networks deployed on the seabed are increasingly enormous, placing ever higher demands on underwater communication technologies. Due to the extreme difficulty of laying underwater fiber optic cables and other wired media, current underwater communication technologies mainly include acoustic communication, wireless optical communication, electromagnetic wave communication, and magnetic induction communication. Acoustic communication was initially developed for military applications, achieving transmission distances of several kilometers. However, sound waves propagate slowly in water, have limited bandwidth, are highly unstable, and may have harmful effects on aquatic life. Underwater optical communication offers advantages such as high speed and low latency, but photons interact with particles in the water, causing light waves to be absorbed and scattered multiple times, severely impacting communication distance and bit error rate. Electromagnetic wave communication, like optical communication, also provides high transmission rates, but its communication distance is significantly reduced due to the high conductivity of seawater. Compared to the other three communication methods, magnetic induction communication does not use a radio frequency antenna but instead uses a coupled coil to induce the magnetic field component in a changing electromagnetic field for communication. It has advantages such as low latency, no multipath effect, and strong penetration capability, making it a promising candidate for applications in complex environments. While various underwater materials have different electrical conductivities, their magnetic permeability remains almost constant. Therefore, changes in the medium have a relatively small impact on magnetic induction communication, avoiding severe Doppler and multipath effects, and its channel state is stable and predictable.

[0003] While magnetic induction communication boasts numerous advantages, its narrow bandwidth limits the potential for increased communication speeds. To improve the spectral efficiency of communication systems, Abualhiga et al. proposed Orthogonal Frequency Division Multiplexing Index Modulation (OFDM-IM). This technique introduces a new dimension—the subcarrier index domain—dividing subcarriers into silent and non-silent parts. Silent subcarriers do not transmit signals, while non-silent subcarriers carry transmission information. The state information between silent and non-silent subcarriers can carry additional information. Currently, OFDM-IM applications are primarily concentrated in two-dimensional constellations. In power-constrained underwater communication, maximizing the minimum Euclidean distance between points in a two-dimensional constellation significantly limits system reliability. Extending the constellation dimension to three, four, or more dimensions can significantly increase the minimum Euclidean distance between constellation points; therefore, extending to a three-dimensional constellation for transmission can improve system reliability under limited power conditions. In terms of transmission method, magnetic induction communication operates in free space, resulting in a large safety exposure surface. Currently, the safety issues of magnetic induction communication are rarely considered. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a signal transmission method, a transmission end, a receiving method and a receiving end based on constellation flat coding.

[0005] To solve the above-mentioned technical problems, the present invention is implemented using the following technical solution.

[0006] In a first aspect, the present invention discloses a signal transmission method based on constellation flattening coding, comprising: Obtain the initial key value, use the initial key value as the initial value of the chaotic encryption system to solve for the chaotic sequence, and use the chaotic sequence to XOR the original data to scramble the data. The initial key value is transformed into a binary key to obtain a binary key. Multiple index information is constructed based on the binary key. Each index information is used to determine the position of the silent subcarrier inserted into a group of active subcarriers. Among the silent subcarriers and active subcarriers, only the active subcarriers are used to carry scrambled data. The scrambled data is mapped to a three-dimensional constellation based on the number of active subcarriers in each active subcarrier group to obtain three-dimensional constellation position data. The silent subcarriers are then mapped to the 0 point of the three-dimensional constellation to obtain three-dimensional constellation position data including the silent subcarriers. Two-dimensional constellation position data are obtained by processing three-dimensional constellation position data, including silent subcarriers, using constellation flattening coding rules; The symbols, active subcarriers, and silent subcarriers in the two-dimensional constellation position data are masked to obtain encrypted data, which is then transmitted.

[0007] Further, the step of obtaining the initial key value, and using the initial key value as the initial value of the chaotic encryption system to solve for the chaotic sequence, includes: Get the initial key value ( x 0, y 0, z 0, w 0), using a 4D chaotic encryption system to initialize the key as its initial value of chaos ( x 0, y 0, z 0, w Solve for 0) to obtain the corresponding initial key value ( x 0, y 0, z 0, w Chaotic sequence of 0) X , Y , Z , W ).

[0008] Further, the step of XORing the original data using the chaotic sequence to obtain scrambled data includes: From chaotic sequences ( X , Y , Z , W In ) X Extracting data from the original data T A sequence of the same length of bits is obtained X 1. For the sequence X Multiplying 1 by a factor, rounding down, and then taking the modulo 2, yields a sequence of 0s and 1s. R Using sequences R Performing an XOR operation yields scrambled data.

[0009] Furthermore, the constellation flattening encoding rules include: For chaotic sequences ( X , Y , Z , W In ) W Multiplying the result by a factor, rounding down, and then taking the modulo 2 yields a binary sequence of 0s and 1s. W 1. From binary sequence W Take out from 1 N The masking vector of the constellation flattening encoding rule is obtained by combining two binary data. W 2; the masking vector W 2 includes 00, 01, 10, and 11; Based on different masking vectors W 2. Perform flattening encoding of the corresponding three-dimensional constellation position data to obtain the corresponding two-dimensional constellation position data.

[0010] Furthermore, the process of masking the symbols, active subcarriers, and silent subcarriers in the two-dimensional constellation position data to obtain encrypted data includes: Using chaotic sequences ( X , Y , Z , W In ) Y and Z Generate symbol masking sequence Q and subcarrier masking sequence P , is represented as: ; in, K The number of symbols representing the subcarrier. L Represents the number of subcarriers, obtained Q and P Not exceeding the number of symbols and the number of subcarriers; fix (·) indicates rounding down to zero; mod(·) indicates returning the remainder; abs (·) indicates taking the absolute value; exist K * K order and L * L In a zero matrix of order 1, arrange the zeros in row and column order respectively. Q and P The value at the position represented is 1, resulting in the symbol masking matrix. Q 1 and subcarrier masking matrix P 1. Using a symbolic masking matrix Q 1 and subcarrier masking matrix P 1. Mask the two-dimensional constellation position data to obtain encrypted data.

[0011] Furthermore, the encrypted data is transmitted via a magnetic communication system.

[0012] Secondly, the present invention also discloses a signal transmission terminal based on constellation flattening coding, comprising: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include instructions for performing the transfer method described in the first aspect.

[0013] Thirdly, the present invention also discloses a signal receiving method based on constellation flattening coding, comprising: Receive encrypted data transmitted by the signal transmission method based on constellation flat coding as described in the first aspect; The encrypted data is processed by extracting the initial key value, passing it through a chaotic system to obtain a chaotic sequence, and then performing symbol and subcarrier recovery and flattening decoding on the encrypted data according to the chaotic sequence. The decoded three-dimensional constellation position data is then inversely mapped, and the inversely mapped data is XORed to recover the original data.

[0014] Fourthly, the present invention also discloses a signal receiver based on constellation flattening coding, characterized in that it comprises: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for performing the receiving method described in the second aspect.

[0015] The beneficial effects achieved by this invention are as follows: To address the issue of large security exposure in free-space transmission of magnetic induction communication, this invention employs encryption methods such as generating masking vectors using a 4D chaotic system to mask flattened coding rules. Furthermore, it compresses a three-dimensional constellation into a two-dimensional constellation for transmission using flattened coding. This invention achieves constellation dimension compression through flattened coding, maximizing the minimum Euclidean distance between constellation points with limited transmission power, and further enhances the security of magnetic induction communication through the masking effect of flattened coding rules. Attached Figure Description

[0016] Figure 1 This is a flowchart based on constellation-based flat coding; Figure 2 This is the phase diagram of the 4D Zhang Model; Figure 3 This is a diagram illustrating the flat coding rules for constellations; Figure 4 This is a schematic diagram illustrating the key indexing and flattening encoding process; Figure 5 These are constellation diagrams before and after flattening encoding; Figure 6 This is a performance comparison chart of 3D-OFDM-IM, where (a) is a performance diagram of 3D-OFDM and 3D-OFDM-IM, and (b) is a performance diagram of 3D-OFDM-IM before and after encryption. Figure 7 This is a schematic diagram of the BER curves for legitimate and illegitimate receivers. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0018] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0019] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] Example 1: This example introduces a signal transmission method based on constellation flattening coding, including: Obtain the initial key value, use the initial key value as the initial value of the chaotic encryption system to solve for the chaotic sequence, and use the chaotic sequence to XOR the original data to scramble the data. The initial key value is transformed into a binary key to obtain a binary key. Multiple index information is constructed based on the binary key. Each index information is used to determine the position of the silent subcarrier inserted into a group of active subcarriers. Among the silent subcarriers and active subcarriers, only the active subcarriers are used to carry scrambled data. The scrambled data is mapped to a three-dimensional constellation based on the number of active subcarriers in each active subcarrier group to obtain three-dimensional constellation position data. The silent subcarriers are then mapped to the 0 point of the three-dimensional constellation to obtain three-dimensional constellation position data including the silent subcarriers. Two-dimensional constellation position data are obtained by processing three-dimensional constellation position data, including silent subcarriers, using constellation flattening coding rules; The symbols, active subcarriers, and silent subcarriers in the two-dimensional constellation position data are masked to obtain encrypted data, which is then transmitted.

[0021] The process of obtaining the initial key value, and using this initial key value as the initial value of the chaotic encryption system to solve for the chaotic sequence, includes: Get the initial key value ( x 0, y 0, z 0, w 0), using a 4D chaotic encryption system to initialize the key as its initial value of chaos ( x 0, y 0, z 0, w Solve for 0) to obtain the corresponding initial key value ( x 0, y 0, z 0, w Chaotic sequence of 0) X , Y , Z , W ).

[0022] The step of XORing the original data using the chaotic sequence to obtain scrambled data includes: From chaotic sequences ( X , Y , Z , W In ) X Extracting data from the original data T A sequence of the same length of bits is obtained X 1. For the sequence X Multiplying 1 by a factor, rounding down, and then taking the modulo 2, yields a sequence of 0s and 1s. R Using sequences R Performing an XOR operation yields scrambled data.

[0023] The constellation flattening coding rules include: For chaotic sequences ( X , Y , Z , W In ) W Multiplying the result by a factor, rounding down, and then taking the modulo 2 yields a binary sequence of 0s and 1s. W 1. From binary sequence W Take out from 1 N The masking vector of the constellation flattening encoding rule is obtained by combining two binary data. W 2; the masking vector W 2 includes 00, 01, 10, and 11; Based on different masking vectors W 2. Perform flattening encoding of the corresponding three-dimensional constellation position data to obtain the corresponding two-dimensional constellation position data.

[0024] The process of masking symbols, active subcarriers, and silent subcarriers in the two-dimensional constellation position data to obtain encrypted data includes: Using chaotic sequences ( X , Y , Z , W In ) Y and Z Generate symbol masking sequence Q and subcarrier masking sequence P , represented as: ; in, K The number of symbols representing the subcarrier. L Represents the number of subcarriers, obtained Q and P Not exceeding the number of symbols and the number of subcarriers; fix (·) indicates rounding down to zero; mod(·) indicates returning the remainder; abs (·) indicates taking the absolute value; exist K * K order and L * L In a zero matrix of order 1, arrange the zeros in row and column order respectively. Q and P The value at the position represented is 1, resulting in the symbol masking matrix. Q 1 and subcarrier masking matrix P 1. Using a symbolic masking matrix Q 1 and subcarrier masking matrix P 1. Mask the two-dimensional constellation position data to obtain encrypted data.

[0025] Example 2, based on the same inventive concept as Example 1, introduces a signal transmission method based on constellation flattening coding. The flowchart of the entire system is as follows. Figure 1As shown, this invention divides subcarriers into two groups: an active subcarrier group and a silent subcarrier group. The silent subcarrier group itself does not carry valid information; it transmits information solely through the position of the silent subcarriers, and this information in the index dimension consumes almost no energy. First, a chaotic sequence is obtained through a 4D chaotic system, and the original data is XORed and scrambled. Then, the initial key value is binary-transformed, and the binary key is represented as index information. The corresponding positions of the silent subcarriers and active subcarriers are mapped according to the binary initial key value, thereby achieving synchronous transmission of the key and information. Next, a three-dimensional constellation mapping is performed to obtain constellation position data. The silent subcarriers are mapped to point 0, and a two-dimensional constellation is obtained by controlling the flattening encoding rules using masking vectors. The symbols and subcarriers are then masked, and finally, the encrypted data is transmitted and verified through a magnetic communication system.

[0026] Specifically, the implementation process includes the following: (1) Chaotic encryption system: In this embodiment, a 4D Zhang model is specifically used to perform chaotic encryption on the data. The model used can be represented as follows: (1); Where X, Y, Z, and W are state variables. , , , Let X, Y, Z, and W be the derivatives of X, Y, Z, and W with respect to time t, and let a, b, c, d, and e be system parameters. When a = 3.04, b = 1.02, c = 9.02, d = 1, and e = 2.02, the system has two positive Lyapunov exponents, proving that the system is a hyperchaotic system. We set the initial values ​​x0, y0, z0, and w0 of this chaotic model as: (0.7570214986, 0.7078942109, 0.8915046149, 1.6827092716). The partial differential equation (1) can be solved using the fourth-order Runge-Kutta method, and the values ​​of the chaotic sequence (X, Y, Z, W) can be obtained. The phase diagram of the D ZhangModel is as follows. Figure 2 As shown, the ranges of the four chaotic sequences are (-9,10), (-10,12), (-4,9), and (-7,7).

[0027] (2) Perform XOR encryption on the original data: (2); As shown in formula (2), we obtain the chaotic sequence X Extracting the original data T A sequence of the same length of bits is obtained X1, and on X 1 Expand 10 6 To increase its randomness, the data is multiplied by 2, then rounded down and modulo 2 to obtain a sequence R of 0s and 1s. Finally, an XOR operation is performed on sequence R to obtain the scrambled data. .

[0028] (3) Masking flattened coding rules: (3); As shown in formula (3), for W Expand by 10 6 To increase its randomness, multiply it by 2, then round it down and modulo 2 to get a binary sequence of 0s and 1s. W 1. Then from W Extracting 64 sets of two-bit binary data from step 1 yields the masking vector for the CFC (constellation flat coding) rule. W 2. For example Figure 3 As shown, we have defined four flattening coding rules. W In section 2, 00, 01, 10, and 11 correspond to a, b, c, and d in the CFC rules, respectively. Here, X, Y, and Z represent the three coordinate axes of the 3D constellation diagram, while x and y represent the two coordinate axes of the 2D constellation diagram. The dashed boxes for the 3D coordinates correspond to the dashed boxes for the 2D coordinates. For example, regarding two 3D coordinates (X... 1, Flattening (Y1, Z1) and (X2, Y2, Z2) and encoding them according to bit order yields the following result: Figure 3 The two-dimensional coordinates (X) shown in (a) 1, Y1), (Z 1, X2 and (Y2, Z2) are selected and encoded by alternating bits in bit order to obtain the following result: Figure 3 The two-dimensional coordinates (X) shown in (b) 1, Y1), (Z 1, X2), (Y2), Z2), are encoded according to the coordinate correspondence order to obtain the following... Figure 3 The two-dimensional coordinates (X1,X2), (Y1,Y2), and (Z1,Z2) shown in (c) are encoded by selecting the first and last bits in bit order to obtain the following... Figure 3 The two-dimensional coordinates (X) shown in (d) 1, Y1), (Z 1, X2, (Y2, Z2).

[0029] (4) Masking of subcarriers and symbols: Next, a symbol masking sequence is generated using the chaotic sequences Y and Z. Q and subcarrier masking sequence P : (4); in, K The number of symbols for the subcarrier. L The number of subcarriers is obtained through formula (4). Q and P Not exceeding the number of symbols and the number of subcarriers. K*K order and L*L In a zero matrix of order 1, arrange the zeros in row and column order respectively. Q and P The value at the position represented is 1, resulting in the symbol masking matrix. Q 1 and subcarrier masking matrix P 1. Then, two matrices are used to mask the data to obtain the final encrypted data.

[0030] (5) The specific process of three-dimensional index modulation and flattening coding: Unlike methods where both the sender and receiver know the key, we cleverly integrate the key into the information to achieve synchronous key transmission and improve system security. First, the initial key values ​​x0, y0, z0, and w0 are converted to binary. Each decimal digit of the initial value is converted into 4 binary digits, with the decimal point defaulting to the decimal number 0, resulting in a 192-bit binary sequence. This sequence is then allocated according to the number of active subcarriers. For example, with eight active subcarriers, the positions of the silent subcarriers are determined using 0-7. Every three bits of binary key data are combined to obtain a 64-bit key index information composed of 0-7. Within a group of subcarriers, the key undergoes IM (index modulation) and CFC masking processing, as follows: Figure 4 As shown.

[0031] like Figure 4 As shown in (a), assuming each subcarrier has only one constellation point, the 16 active subcarriers are grouped in pairs to form 8 virtual active subcarriers within the dashed boxes. Each virtual subcarrier contains two parallel constellation points. X i Y i Z i These represent the coordinate data within the constellation points. The position of the silent subcarrier is determined using the key index information, and the constellation points of the silent subcarrier are mapped to point 0. For example... Figure 4 As shown in (b), a virtual silent subcarrier of the same size is inserted into the eight virtual active subcarriers according to the key index information, resulting in nine virtual subcarrier data. Then, the virtual subcarrier data is processed according to... Figure 3 Encode according to the encoding rule shown in (a) to obtain Figure 4The two-dimensional constellation points shown in (c) are selected according to the CFC perturbation sequence. W Controlled by 2. The constellation diagram before and after CFC is as follows: Figure 5 As shown, it is worth noting that the three-dimensional constellation diagram we use is a regular hexahedron, and its constellation points are composed of 1 and -1. Therefore, the two-dimensional constellation points after CFC also only have 1 and -1, which can be combined to form the two-dimensional constellation diagram of QPSK. Furthermore, the three-dimensional constellation data represented by the key index information also corresponds exactly to the 0 point data of the two-dimensional constellation.

[0032] Flattened coding and chaotic encryption are employed to enhance the security of magnetic induction communication and maximize the minimum Euclidean distance to improve system stability under limited transmission power. Specifically, we perform flattened coding on every pair of three-dimensional coordinates (X1, Y1, Z1) and (X2, Y2, Z2). Encoding in bit order yields two-dimensional coordinates (X1, Y1), (Z1, X2), (Y2, Z2); encoding in the order of the first interval yields (X1, Z1), (Y1, X2), (Y2, Z2); and encoding in the order of the second interval yields (X1, Y1), (Z1, Y2), (X2, Z2). The flattened coding rule is not unique; it primarily involves specific combinations of two three-dimensional coordinate points to obtain three two-dimensional coordinate points. Furthermore, we employ four predefined flattened coding rules and utilize masking vectors generated by a chaotic system to mask and encrypt the flattened coding, thereby improving the stability of three-dimensional index modulation in magnetic induction communication.

[0033] System experimental results: To assess the effectiveness of this scheme, we compared the bit error rate of 3D-OFDM signals with that of unencrypted 3D-OFDM-IM-CFC signals. Figure 6 As shown in (a), the communication distance and bit error rate (BER) of both signals exhibit an inverse relationship. This is because increasing the communication distance leads to a higher signal-to-noise ratio (SNR), affecting communication quality. Furthermore, the BER of the unencrypted 3D-OFDM-IM-CFC signal is slightly better than that of the 3D-OFDM signal. Notably, we found that when the BER is at the threshold value, the communication distance of the unencrypted 3D-OFDM-IM-CFC signal increases by 0.305 cm. This is because 3D-OFDM-IM-CFC introduces an index field in the three-dimensional constellation, improving the system's spectral resources and increasing the energy allocated to each symbol, thereby reducing the impact of noise. These findings validate the feasibility of this scheme in magnetic induction communication and its advantages in improving system spectral resources and noise immunity.

[0034] Figure 6Figure (b) shows the bit error rate performance before and after 3D-OFDM-IM-CFC encryption. The results show that the bit error rate performance is almost identical before and after encryption. This is because, during encryption, the key replaces the index information, and the encryption method only perturbs the CFC rules, scrambles the subcarriers and symbols, without introducing additional information or noise. Therefore, the proposed 3D-OFDM-IM-CFC-based encryption scheme not only has almost no impact on the transmission performance of magnetic communication signals but also effectively achieves synchronous transmission of information and the key.

[0035] like Figure 7 As shown, we analyzed the encryption performance of the signal for both legitimate and illegitimate receivers, where "illegitimate receiver" refers to an unauthorized user. Experiments verified that, under specific CFC rules and encryption masking, the legitimate receiver can correctly recover the data based on the extracted key and known CFC rules. However, the illegitimate receiver cannot recover the correct 3D constellation diagram, and regardless of the method used, it cannot obtain the correct data, with a bit error rate consistently around 0.5. This demonstrates that the proposed scheme can further improve signal security and provides important protection against potential interception and eavesdropping.

[0036] Example 3, based on the same inventive concept as other examples, introduces a signal transmission terminal based on constellation flattening coding, including: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for performing the transmission method described in Embodiment 1.

[0037] Example 4, based on the same inventive concept as other examples, introduces a signal receiving method based on constellation flattening coding, including: Receive encrypted data transmitted by the signal transmission method based on constellation flat coding as described in claim 2; The encrypted data is processed by extracting the initial key value, passing it through a chaotic system to obtain a chaotic sequence, and then performing symbol and subcarrier recovery and flattening decoding on the encrypted data based on the chaotic sequence. The decoded three-dimensional constellation data is then inversely mapped and XORed to obtain the original data.

[0038] Example 5, based on the same inventive concept as other examples, describes a signal receiver based on constellation flattening coding, comprising: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include instructions for performing the receiving method described in Embodiment 4.

[0039] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0040] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0041] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0042] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0043] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A signal transmission method based on constellation flattening coding, characterized in that, include: Obtain the initial key value, use the initial key value as the initial value of the chaotic encryption system to solve for the chaotic sequence, and use the chaotic sequence to XOR the original data to scramble the data. The initial value of the key is transformed into binary to obtain a binary key. Multiple index information is constructed based on the binary key. Each index information is used to determine the position of the silent subcarrier inserted into a group of active subcarriers. Among the silent subcarriers and active subcarriers, only the active subcarriers are used to carry scrambled data. The scrambled data is mapped to a three-dimensional constellation based on the number of active subcarriers in each active subcarrier group to obtain three-dimensional constellation position data. The silent subcarriers are then mapped to the 0 point of the three-dimensional constellation to obtain three-dimensional constellation position data including the silent subcarriers. Two-dimensional constellation position data, including silent subcarriers, is obtained by processing three-dimensional constellation position data using constellation flattening coding rules. The constellation flattening coding rules include: multiplying W in the chaotic sequence (X,Y,Z,W) by a factor, rounding down, and then taking the modulo 2 to obtain a binary sequence W1 of 0s and 1s; extracting N sets of two-bit binary data from the binary sequence W1 to obtain the masking vector W2 of the constellation flattening coding rules; the masking vector W2 includes 00, 01, 10, and 11; and performing corresponding three-dimensional constellation position data flattening coding processing according to different masking vectors W2 to obtain the corresponding two-dimensional constellation position data. Masking the symbols, active subcarriers, and silent subcarriers in the two-dimensional constellation position data yields encrypted data, including: Using Y and Z from the chaotic sequence (X,Y,Z,W), a symbol masking sequence Q and a subcarrier masking sequence P are generated, as follows: ； Where K represents the number of symbols of the subcarrier, L represents the number of subcarriers, and the obtained Q and P do not exceed the number of symbols of the subcarriers and the number of subcarriers; fix(·) means rounding to zero; mod(·) means returning the remainder; abs(·) means taking the absolute value; In the K*K and L*L zero matrices, the positions represented by Q and P are set to 1 in the order of rows and columns, respectively, to obtain the symbol masking matrix Q1 and the subcarrier masking matrix P1. The symbol masking matrix Q1 and the subcarrier masking matrix P1 are used to mask the two-dimensional constellation position data to obtain encrypted data. Transmit encrypted data.

2. The signal transmission method based on constellation flattening coding according to claim 1, characterized in that, The process of obtaining the initial key value, and using this initial key value as the initial value of the chaotic encryption system to solve for the chaotic sequence, includes: Obtain the initial key value (x0, y0, z0, w0), and use the 4D chaotic encryption system to solve the initial key value (x0, y0, z0, w0) which is the initial chaotic value, to obtain the chaotic sequence (X, Y, Z, W) of the corresponding initial key value (x0, y0, z0, w0).

3. The signal transmission method based on constellation flattening coding according to claim 2, characterized in that, The step of XORing the original data using the chaotic sequence to obtain scrambled data includes: Take the same number of bits as the original data T from X in the chaotic sequence (X,Y,Z,W) to get the sequence X1. Multiply the sequence X1 by a factor, round down and then take the modulo 2 to get the sequence R composed of 0 and 1. Perform an XOR operation on the sequence R to get the scrambled data.

4. The signal transmission method based on constellation flattening coding according to claim 1, characterized in that, The encrypted data is transmitted via a magnetic communication system.

5. A signal transmission terminal based on constellation flattening coding, characterized in that, include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for performing any of the transmission methods of claims 1 to 4.

6. A signal receiving method based on constellation flattening coding, characterized in that, include: Receive encrypted data transmitted by the signal transmission method based on constellation flat coding as described in any one of claims 1-4; The encrypted data is processed by extracting the initial key value, passing it through a chaotic system to obtain a chaotic sequence, and then performing symbol and subcarrier recovery and flattening decoding on the encrypted data according to the chaotic sequence. The decoded three-dimensional constellation position data is then inversely mapped, and the inversely mapped data is XORed to recover the original data.

7. A signal receiver based on constellation flat coding, characterized in that, include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for performing the receiving method of claim 6.

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