A CAP data transmission method and system based on probabilistic shaping and Rubik's Cube encryption

Abstract

This invention discloses a CAP data transmission method and system based on probabilistic shaping and Rubik's Cube encryption. The transmitting end performs serial-to-parallel conversion on the original data to obtain three input signals; these three input signals are mapped onto a three-dimensional constellation diagram for mapping encryption processing, while simultaneously undergoing probabilistic shaping to obtain three shaped signals; the three shaped signals are then subjected to Rubik's Cube encryption to obtain three encrypted signals; finally, the three encrypted signals are CAP modulated and combined into a single data transmission signal, which is received by the receiving end and inversely transformed to obtain the original data. This invention improves the utilization rate of constellation points, enhances the system's noise immunity, and improves system security.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of communication, and particularly relates to a CAP data transmission method and system based on probability shaping and Rubik's encryption. BACKGROUND

[0002] With the continuous emergence of 5G, cloud computing, cloud storage, Internet of Things, intelligent driving and other applications, the data capacity required for communication is increasing exponentially, and the growth of terminal users is increasing the demand for bandwidth. Advanced coding and modulation techniques have attracted widespread attention. Carrierless amplitude and phase modulation (CAP) is a multi-dimensional and multi-order modulation technique, which was first proposed by Bell Laboratories in the 1970s. With this modulation technique, high-speed transmission with high spectral efficiency can be achieved under the condition of limited bandwidth. Compared with orthogonal frequency division multiplexing (OFDM), CAP modulation no longer needs to use discrete Fourier transform (DFT), thereby greatly reducing the computational complexity and structure of the system. With the continuous deepening of CAP research, the application of CAP has not only two dimensions, but also three dimensions or even more dimensions. In fact, high-dimensional constellations can further expand the Euclidean distance between constellation points, making the positions of the constellation points more flexible and the encryption methods more diverse. The utilization rate of constellation points in the prior art is low, the anti-noise performance of the system is not strong, and the security of the data needs to be improved. SUMMARY

[0003] To solve the problems in the prior art, the application provides a CAP data transmission method and system based on probability shaping and Rubik's encryption, which improves the utilization rate of constellation points, enhances the anti-noise performance of the system, and improves the security of the system.

[0004] To achieve the above-mentioned purposes, the technical solution adopted by the application is as follows:

[0005] In a first aspect, a data transmission method is provided, comprising: a sending end performing serial / parallel conversion on original data to obtain three input signals; mapping the three input signals to a three-dimensional constellation diagram for mapping and encryption processing, and simultaneously performing probability shaping to obtain three shaped signals; performing Rubik's encryption on the three shaped signals to obtain three encrypted signals; performing CAP modulation on the three encrypted signals and merging them into one data transmission signal, which is used for a receiving end to receive the data transmission signal and perform inverse conversion to obtain the original data.

[0006] Furthermore, the three input signals are mapped onto a three-dimensional constellation diagram for mapping encryption processing, while floating probability shaping is performed. This includes: using a three-dimensional constellation structure composed of two cubes for data mapping; extracting two chaotic sequences X and Y from the five chaotic sequences X, Y, Z, W, and U of the five-dimensional entangled chaotic model; and performing modulo and integer processing on the chaotic sequences X and Y to obtain masking vectors, where X1 and X2 are defined as the two processed masking vectors:

[0007]

[0008] Here, mod represents the modulo operation, and floor represents the floor operation; the masking vector X1 is applied to the 8 constellation points of the outer cube vertices. When the masking vector X1 is 0, the data of the original constellation points remains unchanged; when the masking vector X1 is 1, the data of the outer constellation points is transferred to the adjacent constellation points in the inner layer for modulation, which is used to achieve dynamic probability shaping; the masking vector X2 is applied to all constellation points. When the masking vector X2 is 0, the data of the original constellation points remains unchanged; when the masking vector X2 is not 0, the data of the constellation points is transferred to the adjacent constellation points in the same layer for modulation, which is used to achieve a scrambling effect.

[0009] Furthermore, the dynamic equations of the five-dimensional entangled chaotic model are:

[0010]

[0011] Where x, y, z, w, u are state variables, and a, b, c, d, e, h are system parameters.

[0012] Furthermore, the three-channel shaped signals are encrypted using a Rubik's Cube, including: taking the cube root of the total amount of the three-channel shaped signals to be transmitted and rounding down to obtain the Rubik's Cube order n; then stacking the transmitted binary numbers into an n×n×n three-dimensional cube model; then extracting the sequences Z, W, and U from the five chaotic sequences X, Y, Z, W, and U of the five-dimensional entangled chaotic model, and then performing modulo and integer processing on the sequences Z, W, and U to obtain the encrypted sequences, where Y1, Y2, and Y3 are defined as the processed encrypted sequences:

[0013]

[0014] Step 1: When the encryption sequence Y1 is 1, select the XOY plane for rotation; when the encryption sequence Y1 is 2, select the XOZ plane for rotation; when the encryption sequence Y1 is 3, select the YOZ plane for rotation. Step 2: When the encryption sequence Y2 is 1 to n, determine the 1st to nth layers in the plane direction of Step 1. Step 3: When the encryption sequence Y3 is 1, rotate the layer clockwise by 90°; when the encryption sequence Y3 is 2, rotate the layer clockwise by 180°; when the encryption sequence Y3 is 3, rotate the layer clockwise by 270°; when the encryption sequence Y3 is 4, rotate the layer clockwise by 360°.

[0015] Further, the receiving end receives the data transmission signal and performs an inverse transformation to obtain the original data, including: performing CAP demodulation on the data transmission signal to obtain three encrypted signals; performing Rubik's Cube decryption on the three encrypted signals to obtain three shaped data; performing inverse probability shaping and inverse mapping on the three shaped data to obtain three input signals; and performing serial-to-parallel conversion on the three input signals to obtain the original data.

[0016] Secondly, a data transmission system is provided, comprising: a serial-to-parallel conversion module for the transmitting end to perform serial-to-parallel conversion on the original data to obtain three input signals; a dynamic probability constellation mapping module for mapping the three input signals onto a three-dimensional constellation diagram for mapping encryption processing, and simultaneously performing probability shaping to obtain three shaped signals; a Rubik's Cube encryption module for performing Rubik's Cube encryption on the three shaped signals to obtain three encrypted signals; and a CAP modulation module for performing CAP modulation on the three encrypted signals and merging them into a single data transmission signal, for the receiving end to receive the data transmission signal and perform inverse transformation to obtain the original data.

[0017] Furthermore, the receiving end includes: a CAP demodulation module for demodulating the data transmission signal using CAP to obtain three encrypted signals; a Rubik's Cube decryption module for decrypting the three encrypted signals using Rubik's Cube to obtain three shaped data; a reverse dynamic probability constellation mapping module for performing reverse probability shaping and reverse mapping on the three shaped data to obtain three input signals; and a reverse serial-to-parallel conversion module for performing serial-to-parallel conversion on the three input signals to obtain the original data.

[0018] Compared with existing technologies, the beneficial effects achieved by this invention are as follows: The transmitting end of this invention performs serial-to-parallel conversion on the original data, maps the input signal to a three-dimensional constellation diagram for mapping encryption processing, performs probability shaping, performs Rubik's Cube encryption, and then performs CAP modulation; through dynamic probability shaping technology, the utilization rate of constellation points is improved, the bit error rate performance is improved, and the anti-noise performance of the system is enhanced; at the same time, combined with the Rubik's Cube encryption scheme, dual security processing at the physical layer is achieved, which greatly improves the transmission performance and security performance of the system. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the physical layer data encryption principle of a CAP data transmission system based on probabilistic shaping and Rubik's Cube encryption, provided in an embodiment of the present invention.

[0020] Figure 2 This is an attractor diagram of a five-dimensional entangled chaotic system in an embodiment of the present invention, wherein (a) is about the X, Y and Z sequence, (b) is about the X, Y and W sequence, (c) is about the X and Y sequence, (d) is about the X and Z sequence, (e) is about the Y, Z and W sequence, (f) is about the Y, Z and U sequence, (g) is about the Y and Z sequence, and (h) is about the Y and W sequence;

[0021] Figure 3 This is a schematic diagram of dynamic probability shaping in an embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of Rubik's Cube encryption in an embodiment of the present invention;

[0023] Figure 5 This is a schematic diagram of the Rubik's Cube encryption process in an embodiment of the present invention;

[0024] Figure 6 This is a graph showing the simulation results of the bit error rate in an embodiment of the present invention. Detailed Implementation

[0025] 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.

[0026] Example 1:

[0027] like Figures 1-6 As shown, a CAP data transmission method based on probabilistic shaping and Rubik's Cube encryption includes: the transmitting end performing serial-to-parallel transformation on the original data to obtain three input signals; mapping the three input signals onto a three-dimensional constellation diagram for mapping encryption processing, while simultaneously performing probabilistic shaping to obtain three shaped signals; performing Rubik's Cube encryption on the three shaped signals to obtain three encrypted signals; performing CAP modulation on the three encrypted signals and merging them into a single data transmission signal, which is used by the receiving end to receive the data transmission signal and perform an inverse transformation to obtain the original data.

[0028] The physical layer data encryption principle of this invention is as follows: Figure 1As shown, at the transmitting end, the original data is converted into three input signals through serial-to-parallel conversion. These three input signals are mapped onto a 3D constellation diagram and simultaneously undergo floating probability shaping to obtain three shaped signals. These three shaped signals then enter the cube encryption module to achieve physical layer data encryption, resulting in three encrypted signals. Finally, these three encrypted signals are modulated using CAP and combined into a single signal for transmission. At the receiving end, the process is reversed. The received data is demodulated using CAP and then processed by the cube decryption module and dynamic probability demapping. Finally, the original data is obtained through parallel-to-serial conversion. Specifically, a masking vector and an encryption sequence are generated using a key generated by a chaotic system. The masking vector undergoes mapping and encryption processing in the dynamic probability mapping module, and the encryption sequence is encrypted in the cube encryption module.

[0029] This invention employs a novel five-dimensional entangled chaotic system, and the entangled chaotic dynamic equation is shown in equation (1):

[0030]

[0031] Where x, y, z, w, u are state variables, and a, b, c, d, e, h are system parameters. When a = 2, b = 3, c = 0.5, e = 10, h = 3, the entangled chaotic system exhibits chaotic behavior, and the chaotic attractor is as follows: Figure 2 As shown.

[0032] By comparing the attractor graphs of chaotic sequences in different dimensions, it can be seen that the dimensions of this entangled chaotic system do not interfere with each other, so each set of chaotic sequences can be used as a key for encryption.

[0033] The dynamic probability constellation mapping module maps the three input signals to a three-dimensional constellation diagram for mapping and encryption processing, while simultaneously performing floating probability shaping. In this module, the present invention proposes a dynamic probability shaping scheme. Under the premise of three-dimensional constellation structure mapping, it changes the probability distribution of constellation points, reducing the probability of high-amplitude signals and increasing the probability of low-amplitude signals, thereby improving the utilization rate of constellation points and effectively reducing the average power, thus lowering the system bit error rate at the same transmit power. The present invention uses a three-dimensional constellation structure for data mapping, such as... Figure 3 As shown, the constellation consists of two cubes, with 16 constellation points distributed at the vertices of these two cubes. The minimum Euclidean distance between adjacent constellation points is 2.

[0034] First, two chaotic sequences X and Y are extracted from the five chaotic sequences X, Y, Z, W, and U of the above five-dimensional entangled chaotic model, as shown in formula (2). In order to improve the randomness of the key, the present invention multiplies the sequences by 10 respectively. 3Multiplying by other numbers still achieves the same effect. Then, the sequence is moduloed and rounded to obtain the masking vector, where X1 and X2 are defined as the two sets of masking vectors after processing.

[0035]

[0036] Here, mod represents the modulo operation, and floor represents the floor operation.

[0037] The first step is to apply the masking vector X1 to the eight constellation points of the outer cube. When the masking vector X1 is 0, the data of the original constellation points remains unchanged. When the masking vector X1 is 1, the data of the outer constellation points is transferred to the adjacent constellation points in the inner layer for modulation, which is used to achieve dynamic probability shaping.

[0038] The second step is to apply the masking vector X2 to all constellation points. When the masking vector X2 is 0, the data of the original constellation points remains unchanged; when the masking vector X2 is not 0, the data of the constellation points is transferred to adjacent constellation points on the same layer for modulation, in order to achieve a scrambling effect and improve the security of the module.

[0039] The Rubik's Cube encryption module encrypts the three-way shaping signals. The Rubik's Cube commonly referred to is the 3x3x3 cube, a 3x3x3 cubic structure. The order refers to the number of pieces shared by two adjacent rotating faces of the cube's main body. For example, if each edge of a 3x3x3 Rubik's Cube has 3 pieces, then through rotation, the total number of pieces is 4.3x10. 19 The number of variations increases exponentially with the order of the Rubik's Cube. The number of variations for a positive n (n≥2) order Rubik's Cube is shown in formulas (3) and (4):

[0040] Odd order:

[0041] Even order:

[0042] Where n is the order of the Rubik's Cube, k takes values ​​from 1 to +∞, and N is the total number of changes in the Rubik's Cube. N varies with the value of n, as shown in Table 1.

[0043] Table 1 Examples of the number of transformations for Rubik's Cubes of different orders

[0044]

[0045] As shown in Table 1, the order N of the Rubik's Cube increases exponentially with the increase of the Rubik's Cube order. Therefore, this invention proposes a Rubik's Cube encryption scheme to address the high complexity of the Rubik's Cube. First, this invention needs to calculate the order of the constructed Rubik's Cube, where the total number of signals varies with different transmission signals. The total number of signals of the three shaped signals to be transmitted is cubed and rounded to obtain the order n of the Rubik's Cube. Then, the transmitted binary numbers are stacked into an n×n×n three-dimensional cube model. Then, the sequences Z, W, and U are extracted from the five chaotic sequences X, Y, Z, W, and U of the above chaotic model, as shown in formula (5). Each sequence is multiplied by 10. 3 The randomness of the key is increased, and then the sequences Z, W, and U are moduloed and rounded to obtain the encrypted sequences, where Y1, Y2, and Y3 are defined as the processed encrypted sequences:

[0046]

[0047] The Rubik's Cube encryption scheme involves three steps. First, choose the plane to rotate; second, determine the number of layers to rotate; and finally, determine the angle of rotation. Here, a 4x4 Rubik's Cube with n=4 is used as an example to demonstrate encryption methods under different keys, such as... Figure 4 As shown.

[0048] Step 1: When the encrypted sequence Y1 is 1, select the XOY plane for rotation; when the encrypted sequence Y1 is 2, select the XOZ plane for rotation; when the encrypted sequence Y1 is 3, select the YOZ plane for rotation.

[0049] Step 2: When the encrypted sequence Y2 is 1 to n, that is, determine the 1st to nth layers in the planar direction of the first step;

[0050] Step 3: When the encryption sequence Y3 is 1, rotate the layer 90° clockwise; when the encryption sequence Y3 is 2, rotate the layer 180° clockwise; when the encryption sequence Y3 is 3, rotate the layer 270° clockwise; when the encryption sequence Y3 is 4, rotate the layer 360° clockwise.

[0051] One important point to note is that each rotation is based on the previous rotation. A specific example is shown below. Figure 5 As shown.

[0052] The receiving end receives the data transmission signal and performs an inverse transformation to obtain the original data, including: performing CAP demodulation on the data transmission signal to obtain three encrypted signals; performing Rubik's Cube decryption on the three encrypted signals to obtain three shaped data; performing inverse probability shaping and inverse mapping on the three shaped data to obtain three input signals; and performing serial-to-parallel conversion on the three input signals to obtain the original data.

[0053] This invention uses a Gaussian white noise channel as a simulated transmission channel to test the bit error rate comparison of dynamic probability shaping with Rubik's Cube encrypted signals, Rubik's Cube encrypted signals, and control group signals under different optical powers. The results are as follows: Figure 6 As shown in the figure, the bit error rate performance based on dynamic probability shaping is significantly better than the other two groups, indicating that dynamic probability shaping can greatly improve the transmission performance of the system. Meanwhile, the bit error rate of the illegal receiver signal remains around -0.3, demonstrating the excellent security of the entire system.

[0054] Example 2:

[0055] Based on the CAP data transmission method based on probabilistic shaping and Rubik's Cube encryption described in Embodiment 1, this embodiment provides a CAP data transmission system based on probabilistic shaping and Rubik's Cube encryption.

[0056] The sending end includes:

[0057] The serial-to-parallel conversion module is used by the transmitting end to perform serial-to-parallel conversion on the original data to obtain three input signals;

[0058] The dynamic probability constellation mapping module is used to map three input signals onto a three-dimensional constellation diagram for mapping encryption processing, and at the same time perform probability shaping to obtain three shaped signals.

[0059] The Rubik's Cube encryption module is used to encrypt the three-way shaped signals to obtain three-way encrypted signals.

[0060] The CAP modulation module is used to perform CAP modulation on three encrypted signals and merge them into one data transmission signal. The receiving end receives the data transmission signal and performs inverse transformation to obtain the original data.

[0061] The receiving end includes:

[0062] The CAP demodulation module is used to demodulate the data transmission signal using CAP to obtain three encrypted signals;

[0063] The Rubik's Cube decryption module is used to decrypt the three encrypted signals to obtain three channels of shaped data.

[0064] The reverse dynamic probability constellation mapping module is used to perform reverse probability shaping and reverse mapping on three-channel shaped data to obtain three-channel input signals.

[0065] The inverse serial-to-parallel conversion module is used to convert the three input signals from serial to parallel to obtain the original data.

[0066] 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 data transmission method, characterized by, The method comprises the following steps: The sending end performs serial-to-parallel conversion on the original data to obtain three input signals; The three input signals are mapped to a three-dimensional constellation for mapping and encryption processing, and probability shaping is performed simultaneously to obtain three shaped signals; The three shaped signals are encrypted by a magic cube to obtain three encrypted signals; The three encrypted signals are CAP-modulated and combined into one data transmission signal, which is used by the receiving end to receive the data transmission signal and perform reverse conversion to obtain the original data; The mapping and encryption processing of the three input signals to the three-dimensional constellation also includes floating probability shaping, which comprises the following steps: A three-dimensional constellation structure composed of two positive cubes is used for data mapping, and two groups of chaotic sequences X and Y are extracted from five groups of chaotic sequences X, Y, Z, W and U of a five-dimensional entangled chaotic model, and the chaotic sequences X and Y are processed by taking the remainder and the integer to obtain a mask vector, wherein X1 and X2 are defined as the two groups of processed mask vectors: （2） wherein mod denotes a modulo operation, denotes a rounding operation; The mask vector X1 is applied to the 8 constellation points of the outer cube vertex, when the mask vector X1 is 0, the data of the original constellation point remains unchanged; when the mask vector X1 is 1, the data of the outer constellation point is transferred to the adjacent constellation point in the inner layer for modulation, which is used to realize dynamic probability shaping; The mask vector X2 is applied to all constellation points, when the mask vector X2 is 0, the data of the original constellation point remains unchanged; when the mask vector X2 is not 0, the data of the constellation point is transferred to the adjacent constellation point in the same layer for modulation, which is used to realize the scrambling effect.

2. The data transmission method of claim 1, wherein, The dynamic equation of the five-dimensional entangled chaotic model is: （1） wherein x , y , z , w , u is a state variable, a , b , c , d , e, h is a system parameter.

3. The data transmission method of claim 2, wherein, The magic cube encryption of the three shaped signals comprises the following steps: The total number of signals changes with different transmission signals, the total number of the three shaped signals to be transmitted is operated by taking the cube root and taking the integer to obtain the magic cube order n; then the transmission binary number is stacked into an n×n×n three-dimensional cubic array model; then the sequences Z, W and U are extracted from the five groups of chaotic sequences X, Y, Z, W and U of the five-dimensional entangled chaotic model, and the chaotic sequences Z, W and U are processed by taking the remainder and the integer to obtain an encrypted sequence, wherein Y1, Y2 and Y3 are defined as the processed encrypted sequence: （5） First step: when the encrypted sequence Y1 is 1, the XOY plane is selected for rotation; when the encrypted sequence Y1 is 2, the XOZ plane is selected for rotation; when the encrypted sequence Y1 is 3, the YOZ plane is selected for rotation; Second step: when the encrypted sequence Y2 is 1-n, the 1st-nth layer in the first step plane direction is determined; Third step: when the encrypted sequence Y3 is 1, the layer is rotated clockwise by 90°; when the encrypted sequence Y3 is 2, the layer is rotated clockwise by 180°; when the encrypted sequence Y3 is 3, the layer is rotated clockwise by 270°; when the encrypted sequence Y3 is 4, the layer is rotated clockwise by 360°.

4. The data transmission method of claim 3, wherein, The receiving end receives the data transmission signal and performs reverse conversion to obtain the original data, which comprises the following steps: The data transmission signal is CAP-demodulated to obtain three encrypted signals; The three encrypted signals are decrypted by a magic cube to obtain three shaped data; Reverse probability shaping and reverse mapping are performed on the three-path shaped data to obtain three-path input signals; Serial / parallel conversion is performed on the three-path input signals to obtain original data.

5. A data transmission system, characterized in that The method comprises the following steps: a serial / parallel conversion module is configured to perform serial / parallel conversion on the original data at the sending end to obtain three-path input signals; a dynamic probability constellation mapping module is configured to map the three-path input signals to a three-dimensional constellation diagram to perform mapping encryption processing and probability shaping at the same time, and obtain three-path shaped signals; a magic cube encryption module is configured to perform magic cube encryption on the three-path shaped signals to obtain three-path encrypted signals; a CAP modulation module is configured to perform CAP modulation on the three-path encrypted signals and combine them into one data transmission signal, and the receiving end is configured to receive the data transmission signal and perform reverse conversion to obtain the original data; wherein the three-path input signals are mapped to a three-dimensional constellation diagram to perform mapping encryption processing and floating probability shaping, which comprises the following steps: a three-dimensional constellation structure composed of two positive cubes is adopted to perform data mapping, two groups of chaotic sequences X and Y are extracted from five groups of chaotic sequences X, Y, Z, W and U of a five-dimensional entangled chaotic model, and the chaotic sequences X and Y are subjected to modulo and integer processing to obtain a masking vector, wherein X1 and X2 are defined as the two groups of processed masking vectors: （2） wherein mod denotes a modulo operation, denotes a rounding operation; the masking vector X1 is applied to eight constellation points at the vertices of the outer cube, when the masking vector X1 is 0, the data of the original constellation point remains unchanged; when the masking vector X1 is 1, the data of the outer constellation point is transferred to the adjacent constellation point in the inner layer for modulation, which is used to realize dynamic probability shaping; the masking vector X2 is applied to all constellation points, when the masking vector X2 is 0, the data of the original constellation point remains unchanged; when the masking vector X2 is not 0, the data of the constellation point is transferred to the adjacent constellation point in the same layer for modulation, which is used to realize the scrambling effect.

6. The data transmission system of claim 5, wherein, The receiving end comprises: a CAP demodulation module is configured to perform CAP demodulation on the data transmission signal to obtain three-path encrypted signals; a magic cube decryption module is configured to perform magic cube decryption on the three-path encrypted signals to obtain three-path shaped data; a reverse dynamic probability constellation mapping module is configured to perform reverse probability shaping and reverse mapping on the three-path shaped data to obtain three-path input signals; a reverse serial / parallel conversion module is configured to perform serial / parallel conversion on the three-path input signals to obtain original data.

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