A probabilistic shaping encryption method, decryption method, encryption system, and decryption system based on symbol-level chaotic labels.

Abstract

This invention discloses a probabilistic shaping encryption method, decryption method, encryption system, and decryption system based on symbol-level chaotic tags in the field of optical communication transmission technology. The method includes: performing serial-to-parallel conversion on the signal to be transmitted to obtain a parallel signal; generating a first chaotic encryption sequence, a second chaotic encryption sequence, and a third chaotic encryption sequence using a three-dimensional chaotic system; performing symbol-level chaotic tag conversion on the parallel signal using the first chaotic encryption sequence to obtain a symbol-level encrypted signal; performing asymmetric polygon constellation mapping on the symbol-level encrypted signal to obtain an 8QAM constellation; performing symbol masking and subcarrier masking on the second and third chaotic encryption sequences to obtain a first scrambling matrix and a second scrambling matrix; scrambling the 8QAM constellation using the first and second scrambling matrices, performing an inverse Fourier transform, and adding a cyclic prefix to obtain an encrypted transmittable signal.

Description

Technical Field

[0001] This invention relates to the field of optical communication transmission technology in the field of communication technology, and particularly to a probabilistic shaping encryption method, decryption method, encryption system and decryption system based on symbol-level chaotic tags. Background Technology

[0002] With the widespread application and continuous development of big data, cloud computing, and virtual reality in social life, these technologies have not only facilitated daily communication but also enhanced global connectivity, fundamentally reshaping the landscape of future living experiences. Simultaneously, to cope with the exponential traffic growth driven by these emerging network technologies and applications, existing networks must be upgraded to new architectures with faster speeds, wider coverage, and greater capacity. In terms of access networks, Passive Optical Networks (PONs) have proven to be a future-oriented architecture surpassing traditional cable modems due to their significant advantages such as low power consumption, high transmission rates, and wide coverage. However, PON systems still face two core challenges: First, the rigidity of constellation design. In traditional rectangular quadrature amplitude modulation (QAM) constellations, the finite minimum Euclidean distance limits further improvements in receiver sensitivity; second, broadcast vulnerabilities. In the downlink direction, passive splitters broadcast the same optical signal to all Optical Network Units (ONUs). If the physical layer is not effectively encrypted, transmitted data can easily be intercepted by non-target ONUs, leading to information leakage.

[0003] Probability shaping (PS) aims to improve power efficiency by reducing the probability of high-energy external constellation points, thereby reducing average signal power. Typically, external constellation points are remapped into internal regions to reduce average transmit power. This strategy effectively reduces average signal energy and improves spectral efficiency. Given these advantages, constellation shaping techniques hold considerable promise for next-generation optical access network architectures, offering significant potential for increasing channel transmission capacity. However, in traditional star and rectangular constellations, significant spatial gaps exist as signal points converge towards the decision region, leading to underutilization of system resources. Therefore, developing new constellation optimization methods is imperative.

[0004] To address the inherent information leakage risks in broadcast channels, physical layer chaotic encryption has become an important method for enhancing downlink security, leveraging its extreme sensitivity to initial conditions, unpredictable dynamic behavior, and noise-like characteristics. However, most existing schemes treat security enhancement as a design goal independent of transmission performance. Their encryption operations often introduce additional performance overhead or remain decoupled from constellation shaping mechanisms, failing to achieve deep integration between security enhancement and transmission optimization. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a probabilistic shaping encryption method, decryption method, encryption system and decryption system based on symbol-level chaotic labels. A new symbol-level chaotic label mapping rule is designed to compress 16 signal points into 8 signal points, effectively reducing the modulation order and improving transmission efficiency. Combined with a three-dimensional chaotic system, physical layer encryption is achieved by using multi-dimensional chaotic vector perturbation, which effectively improves the security of the system.

[0006] To solve the above-mentioned technical problems, the present invention is implemented using the following technical solution:

[0007] In a first aspect, the present invention provides a probabilistic shaping encryption method based on symbol-level chaotic labels, comprising:

[0008] The signal to be transmitted is converted from serial to parallel to obtain a parallel signal;

[0009] Generating the first chaotic encryption sequence using a three-dimensional chaotic system Second chaotic encryption sequence and the third chaotic encryption sequence ;

[0010] Using the first chaotic encryption sequence The parallel signal is subjected to symbol-level chaotic label conversion to obtain a symbol-level encrypted signal;

[0011] The symbol-level encrypted signal is mapped using an asymmetric polygon constellation to obtain an 8QAM constellation;

[0012] The second chaotic encryption sequence Symbol masking and subcarrier masking are performed to obtain the first scrambling matrix. ;

[0013] The third chaotic encryption sequence Symbol masking and subcarrier masking are performed to obtain the second scrambling matrix. ;

[0014] Using the first scrambling array Second Scrambled Array The 8QAM constellation is scrambled to obtain the 8QAM scrambled signal;

[0015] After performing an inverse Fourier transform on the 8QAM scrambled signal, a cyclic prefix is ​​added to obtain an encrypted transmittable signal.

[0016] Optionally, the expression for the three-dimensional chaotic system is as follows:

[0017] ,

[0018] in, For state variables, These are the preset parameters for the three-dimensional chaotic system.

[0019] Optionally, the first chaotic encryption sequence is used. The parallel signal is subjected to symbol-level chaotic label conversion to obtain a symbol-level encrypted signal, including:

[0020] From the first chaotic encryption sequence Extract a subsequence of the same length as the parallel signal, and then perform expansion, rounding, and modulo operations on this subsequence to obtain a binary sequence. ;

[0021] The parallel signal is grouped into sets of 4 bits each to obtain... Grouped bit sequences; where, This is the default value;

[0022] For any bit sequence According to the preset mapping rules, it is mapped from 4 bits to 3 bits, resulting in... Group modulation symbols; where, For indexing, , Indicates the first Grouped bit sequences;

[0023] For any modulation symbol From the binary sequence Extracting modulation symbols Chaos tag Obtain symbol-level encrypted signal points ;in, Indicates the first Group modulation symbols, Indicates the first Each code element-level encrypted signal point;

[0024] By combining all the symbol-level encrypted signal points, we obtain the symbol-level encrypted signal. ;in, , Indicates the first Each code element-level encrypted signal point;

[0025] The binary sequence It can be obtained through the following formula:

[0026] ,

[0027] in, This indicates a round-down operation. Indicates a modulo operation;

[0028] The modulation symbol Chaos tag It can be obtained through the following formula:

[0029] ,

[0030] in, Represents binary sequence The Middle Each element value Represents binary sequence The Middle Each element value;

[0031] The code element-level encrypted signal point It can be obtained through the following formula:

[0032] ,

[0033] in, Indicates modulation symbol The first bit value, Indicates modulation symbol The second bit value, Indicates modulation symbol The third bit value.

[0034] Optionally, for any bit sequence According to the preset mapping rules, it is mapped from 4 bits to 3 bits, including:

[0035] If the bit sequence If it is 0000 or 0011, convert it to 000 to obtain the modulation symbol. ;

[0036] If the bit sequence If it is 0001 or 1100, convert it to 001 to obtain the modulation symbol. ;

[0037] If the bit sequence If it is 0010 or 1101, convert it to 010 to obtain the modulation symbol. ;

[0038] If the bit sequence If the value is 1000 or 1011, convert it to 100 to obtain the modulation symbol. ;

[0039] If the bit sequence If the value is 1001 or 0111, convert it to 110 to obtain the modulation symbol. ;

[0040] If the bit sequence If the value is 0100 or 0101, convert it to 101 to obtain the modulation symbol. ;

[0041] If the bit sequence If the value is 0110 or 1010, convert it to 011 to obtain the modulation symbol. ;

[0042] If the bit sequence If it is 1111 or 1110, convert it to 111 to obtain the modulation symbol. .

[0043] Optionally, the step of performing asymmetric polygon constellation mapping on the symbol-level encrypted signal to obtain an 8QAM constellation includes:

[0044] By traversing all symbol-level encrypted signal points in the symbol-level encrypted signal, and performing the following judgments, the 8QAM constellation is obtained:

[0045] If the modulation symbol of the symbol-level encrypted signal point is 000, then map this symbol-level encrypted signal point to the IQ plane. coordinate;

[0046] If the modulation symbol of the symbol-level encrypted signal point is 001, then the symbol-level encrypted signal point is mapped to the IQ plane. Coordinates; where, This is the preset scaling factor;

[0047] If the modulation symbol of the symbol-level encrypted signal point is 010, then map this symbol-level encrypted signal point to the IQ plane. coordinate;

[0048] If the modulation symbol of the symbol-level encrypted signal point is 100, then the symbol-level encrypted signal point is mapped to the IQ plane. coordinate;

[0049] If the modulation symbol of the symbol-level encrypted signal point is 110, then map this symbol-level encrypted signal point to the IQ plane. coordinate;

[0050] If the modulation symbol of the symbol-level encrypted signal point is 101, then map this symbol-level encrypted signal point to the IQ plane. coordinate;

[0051] If the modulation symbol of the symbol-level encrypted signal point is 011, then map this symbol-level encrypted signal point to the IQ plane. coordinate;

[0052] If the modulation symbol of the symbol-level encrypted signal point is 111, then map this symbol-level encrypted signal point to the IQ plane. coordinate.

[0053] Optionally, the first scrambling array Second Scrambled Array It can be obtained through the following formula:

[0054] ,

[0055] in, This indicates a modulo operation. This is an ascending sorting function. This represents the second chaotic sequence after the modulo expansion. This represents the third chaotic sequence after the extended modulo operation.

[0056] Optionally, the first scrambling array is used. Second Scrambled Array The 8QAM constellation is scrambled to obtain an 8QAM scrambled signal, including:

[0057] Obtain the first scrambling array respectively Second Scrambled Array The position of element 1 in the sequence yields the first scrambled sequence. Second scrambled sequence ;

[0058] Using the first scrambling sequence Second scrambled sequence The 8QAM constellation is scrambled to obtain the 8QAM scrambled signal;

[0059] The 8QAM scrambling signal is obtained using the following formula:

[0060] ,

[0061] in, Represents the 8QAM constellation. This indicates the 8QAM scrambling signal.

[0062] Secondly, the present invention provides a probabilistic shaping decryption method based on symbol-level chaotic labels, comprising:

[0063] After removing the cyclic prefix from the received data, a Fourier transform is performed to obtain the 8QAM scrambled signal;

[0064] The scrambled 8QAM signal is scrambled and restored to obtain an 8QAM constellation;

[0065] The 8QAM constellation is subjected to asymmetric polygon constellation inverse mapping to obtain a symbol-level encrypted signal;

[0066] The symbol-level encrypted signal is subjected to symbol-level chaotic label inverse conversion to obtain a parallel signal;

[0067] The parallel signal is converted from parallel to serial to obtain the data to be transmitted;

[0068] The received data is obtained by using the encrypted transmittable signal obtained by the method described in any one of the first aspects.

[0069] Thirdly, the present invention provides a probabilistic shaping encryption system based on symbol-level chaotic labels, comprising:

[0070] The serial-to-parallel conversion module is used to convert the signal to be transmitted from serial to parallel to obtain a parallel signal.

[0071] The chaotic encryption module is used to: generate a first chaotic encryption sequence using a three-dimensional chaotic system. Second chaotic encryption sequence and the third chaotic encryption sequence ;

[0072] The symbol-level chaotic label conversion module is used to: utilize the first chaotic encryption sequence The parallel signal is subjected to symbol-level chaotic label conversion to obtain a symbol-level encrypted signal;

[0073] An asymmetric polygon constellation mapping module is used to: perform asymmetric polygon constellation mapping on the symbol-level encrypted signal to obtain an 8QAM constellation;

[0074] The masking processing module is used to: process the second chaotic encryption sequence. Symbol masking and subcarrier masking are performed to obtain the first scrambling matrix. ; for the third chaotic encryption sequence Symbol masking and subcarrier masking are performed to obtain the second scrambling matrix. ;

[0075] The scrambling module is used to: utilize the first scrambling array Second Scrambled Array The 8QAM constellation is scrambled to obtain the 8QAM scrambled signal;

[0076] The inverse Fourier transform and cyclic prefix addition module is used to: perform an inverse Fourier transform on the 8QAM scrambled signal and add a cyclic prefix to obtain an encrypted and transmittable signal.

[0077] Fourthly, the present invention provides a probabilistic shaping decryption system based on symbol-level chaotic labels, comprising:

[0078] The Fourier transform and cyclic prefix removal module is used to: remove the cyclic prefix of the received data and then perform a Fourier transform to obtain the 8QAM scrambled signal;

[0079] The scrambling and restoration processing module is used to: perform scrambling and restoration processing on the 8QAM scrambled signal to obtain an 8QAM constellation;

[0080] The asymmetric polygon constellation inverse mapping module is used to: perform asymmetric polygon constellation inverse mapping on the 8QAM constellation to obtain a symbol-level encrypted signal;

[0081] The symbol-level chaotic label inverse conversion module is used to: perform symbol-level chaotic label inverse conversion on the symbol-level encrypted signal to obtain a parallel signal;

[0082] Parallel-to-serial conversion module, used to: convert the parallel signal into a parallel-to-serial signal to obtain the data to be transmitted;

[0083] The received data is obtained by using the encrypted transmittable signal obtained by the method described in any one of the first aspects.

[0084] Compared with existing technologies, the beneficial effects achieved by this invention are as follows:

[0085] 1. A novel symbol-level chaotic label mapping rule was designed, which compresses 16 constellation points into 8 constellation points, effectively reducing the modulation order and improving transmission efficiency. Combined with a three-dimensional chaotic system, physical layer encryption is achieved by using multi-dimensional chaotic vector perturbation, which effectively improves the security of the system.

[0086] 2. The newly designed constellation improves space utilization and has a higher constellation gain index (CFM) compared to conventional rectangular constellations. Furthermore, by adjusting the distribution of signal point probabilities, it reduces the system's average transmit power and nonlinear impairments.

[0087] 3. The high-security PS-16-8QAM overall mapping scheme based on symbol-level chaotic labels has almost no impact on the transmission performance of the probability shaping signal itself, and the key space can reach [missing information]. This effectively ensures the physical layer security of the system. Attached Figure Description

[0088] Figure 1 The flowcharts for the probabilistic shaping encryption and decryption methods based on symbol-level chaotic labels provided in the embodiments of the present invention are shown below.

[0089] Figure 2 A phase diagram of a three-dimensional chaotic model provided according to an embodiment of the present invention;

[0090] Figure 3 This is a schematic diagram of symbol-level chaotic label conversion provided according to an embodiment of the present invention;

[0091] Figure 4 This is a comparison diagram of asymmetric polygonal constellations and conventional rectangular constellations provided according to an embodiment of the present invention;

[0092] Figure 5 This is an asymmetric polygon constellation mapping and probability distribution diagram provided according to an embodiment of the present invention;

[0093] Figure 6 A schematic diagram of an experimental apparatus based on a 7-core optical fiber according to an embodiment of the present invention;

[0094] Figure 7 The figure shows the simulation comparison results of BER performance between encrypted PS-16-8QAM and conventional 16QAM and 8QAM provided according to an embodiment of the present invention.

[0095] Figure 8 The graph shows the sensitivity analysis results of the initial values ​​of the three-dimensional chaos model provided in the embodiment of the present invention. Detailed Implementation

[0096] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments and specific features in the embodiments are detailed descriptions of the technical solution of the present application, rather than limitations thereof. In the absence of conflict, the embodiments and technical features in the embodiments can be combined with each other.

[0097] It should be noted that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0098] Example 1

[0099] This invention discloses a probabilistic shaping encryption method based on symbol-level chaotic labels, with reference to... Figure 1 As shown, the specific steps include the following:

[0100] S1, perform serial-to-parallel conversion on the signal to be transmitted to obtain a parallel signal;

[0101] S2, using a three-dimensional chaotic system to generate the first chaotic encryption sequence. Second chaotic encryption sequence and the third chaotic encryption sequence ;

[0102] S3, using the first chaotic encryption sequence The parallel signal is subjected to symbol-level chaotic label conversion to obtain a symbol-level encrypted signal;

[0103] S4, perform asymmetric polygon constellation mapping on the symbol-level encrypted signal to obtain an 8QAM constellation;

[0104] S5, the second chaotic encryption sequence Symbol masking and subcarrier masking are performed to obtain the first scrambling matrix. ;

[0105] S6, the third chaotic encryption sequence Symbol masking and subcarrier masking are performed to obtain the second scrambling matrix. ;

[0106] S7, using the first scrambling array Second Scrambled Array The 8QAM constellation is scrambled to obtain the 8QAM scrambled signal;

[0107] S8. After performing an inverse Fourier transform on the 8QAM scrambled signal, a cyclic prefix is ​​added to obtain transmittable data.

[0108] This embodiment proposes a high-security PS-16-8QAM overall mapping scheme based on symbol-level chaotic labels. At the transmitter, the raw data is first processed by serial-to-parallel (S / P) conversion, and then converted by symbol-level chaotic labels. The generated modulation symbols are combined with the labels generated by the three-dimensional chaotic system and then mapped onto an asymmetric polygon constellation. The chaotic model dynamically generates a chaotic encryption sequence according to its initial conditions, which is used to encrypt the constellation points on each subcarrier. Before being transmitted through optical fiber, the signal undergoes inverse fast Fourier transform (IFFT) and the addition of a cyclic prefix (CP).

[0109] Specifically, in step S1, at the transmitting end, the original signal to be transmitted is first processed by serial-to-parallel (S / P) conversion.

[0110] In step S2, this embodiment utilizes a three-dimensional chaotic system to generate a chaotic encryption sequence. The chaotic system can be described by the following expression:

[0111] ,

[0112] in, For state variables, These are the preset parameters for the three-dimensional chaotic system.

[0113] when At that time, the three-dimensional chaotic system exhibits chaotic behavior. In this embodiment, the initial value of the three-dimensional chaotic system is set to... Partial differential equations can be solved using the Runge-Kutta method to generate three-dimensional chaotic sequences; the phase diagram of the specific three-dimensional chaotic model is as follows: Figure 2 As shown, it includes the XZ phase, XY phase, and YZ phase.

[0114] In step S3, the first chaotic encryption sequence is used. The parallel signal is subjected to symbol-level chaotic label conversion to obtain a symbol-level encrypted signal, including:

[0115] From the first chaotic encryption sequence Extract a subsequence of the same length as the parallel signal and expand the subsequence. To enhance randomness, the result is doubled, then rounded down and modulo 2 to obtain a binary sequence consisting of 0s and 1s. :

[0116] ,

[0117] in, This indicates a round-down operation. Indicates a modulo operation;

[0118] The parallel signal is grouped into sets of 4 bits each to obtain... Grouped bit sequences; where, This is the default value;

[0119] For any bit sequence According to the preset mapping rules, it is mapped from 4 bits to 3 bits, resulting in... Group modulation symbols; where, For indexing, , Indicates the first Grouped bit sequences;

[0120] For any modulation symbol From the binary sequence Extract the 2-bit binary data corresponding to the 3-bit modulation symbol to obtain the modulation symbol. Chaos tag :

[0121] ,

[0122] in, Represents binary sequence The Middle Each element value Represents binary sequence The Middle Each element value;

[0123] Extract the 2-bit chaotic label With 3-bit modulation symbols Combining these, we can obtain the final 5-bit output symbol-level encrypted signal points. :

[0124] ,

[0125] in, Indicates modulation symbol The first bit value, Indicates modulation symbol The second bit value, Indicates modulation symbol The third bit value; Indicates the first Group modulation symbols, Indicates the first Each code element-level encrypted signal point;

[0126] By combining all the symbol-level encrypted signal points, we obtain the symbol-level encrypted signal. ;in, , Indicates the first Each code-level encrypted signal point.

[0127] refer to Figure 3 As shown, for any bit sequence According to the preset mapping rules, it is mapped from 4 bits to 3 bits, including:

[0128] If the bit sequence If it is 0000 or 0011, convert it to 000 to obtain the modulation symbol. ;

[0129] If the bit sequence If it is 0001 or 1100, convert it to 001 to obtain the modulation symbol. ;

[0130] If the bit sequence If it is 0010 or 1101, convert it to 010 to obtain the modulation symbol. ;

[0131] If the bit sequence If the value is 1000 or 1011, convert it to 100 to obtain the modulation symbol. ;

[0132] If the bit sequence If the value is 1001 or 0111, convert it to 110 to obtain the modulation symbol. ;

[0133] If the bit sequence If the value is 0100 or 0101, convert it to 101 to obtain the modulation symbol. ;

[0134] If the bit sequence If the value is 0110 or 1010, convert it to 011 to obtain the modulation symbol. ;

[0135] If the bit sequence If it is 1111 or 1110, convert it to 111 to obtain the modulation symbol. .

[0136] In this embodiment, the final output configuration The codeword is 5 bits long: 3 bits carry the shaped encoding information, and the remaining 2 bits are used as symbol-level chaotic labels. These labels are extracted from W ("00", "01") and used to distinguish the original 16 signal points. The weight of the codeword is defined as the number of its non-zero elements. Specifically, for a codeword with a weight of 0, "000" is compressed from the bit sequences "0000" and "0011". To distinguish them, a unique 2-bit chaotic label ("00", "01") is added, resulting in the final outputs "00000" and "00001" respectively. For a weight of 1, "001", "010", and "100" are compressed from the signal point groups "0001 / 1100", "0010 / 1101", and "1000 / 1011" respectively. Each group is then distinguished by its unique 2-bit chaotic label, resulting in the final outputs "00100 / 00101", "01000 / 01001", and "10000 / 10001". Similarly, for weight 2 codewords, "110", "101", and "011" are compressed from signal point groups "1001 / 0111", "0100 / 0101", and "0110 / 1010", respectively. Each original sequence is distinguished by a unique 2-bit chaotic label, resulting in the final outputs: "11000 / 11001", "10100 / 10101", and "01100 / 01101". For weight 3, "111" is compressed from "1111" and "1110", distinguished by a unique 2-bit chaotic label. Signal points labeled "00" are assigned a higher transmission probability and mapped to the innermost, lowest-energy region of the constellation. This design increases the proportion of low-weight codewords in the transmitter, thereby improving overall power efficiency.

[0137] The final distribution of constellation points after probability shaping can be described as follows:

[0138] ,

[0139] in, Indicates a signal point. This represents the set of 8 constellation points generated through probabilistic shaping. express probability distribution, weighting factor and These correspond to the forming signal point and the tag combination ratio, respectively, and satisfy the normalization constraint. . This represents the probability of the underlying modulation symbol prior to the chaotic label, where This represents a predefined modulation symbol. Meanwhile, This represents the probability of grouping with a symbol-level chaotic label, where and It is a single chaos label and The probability of its occurrence. This indicates two symbol-level labels. and The joint probability of the generated signal points. By adjusting the label combination probability, the overall distribution of the new signal points can be reshaped, thereby reducing the average signal energy.

[0140] The 16-8QAM probabilistic shaping scheme proposed in this embodiment maps 4-bit input to 5-bit output by combining 3-bit predefined modulation symbols and 2-bit symbol-level chaotic labels; the systematic grouping and mapping of these bits enables an optimized probability distribution in the 8QAM constellation. The final distribution of the shaped constellation points is shown in Table 1. The results confirm that probabilistic shaping successfully transforms the original uniform distribution of 16 points into an optimized non-uniform distribution of 8 points. The calculated final probability distribution of the shaped 8QAM constellation points is shown in Table 1. The results show that probabilistic shaping effectively transforms the original uniform distribution of 16 signal points into an optimized non-uniform distribution of 8 points.

[0141] Table 1. Probability distribution of the 8 newly generated signal points after probabilistic shaping

[0142] signal point 000 001 010 100 101 110 011 111 probability 0.28 0.15 0.18 0.16 0.085 0.065 0.05 0.03

[0143] In step S4, the asymmetric polygon constellation mapping of the symbol-level encrypted signal to obtain an 8QAM constellation includes:

[0144] By traversing all symbol-level encrypted signal points in the symbol-level encrypted signal, and performing the following judgments, the 8QAM constellation is obtained:

[0145] If the modulation symbol of the symbol-level encrypted signal point is 000, then map this symbol-level encrypted signal point to the IQ plane. coordinate;

[0146] If the modulation symbol of the symbol-level encrypted signal point is 001, then the symbol-level encrypted signal point is mapped to the IQ plane. Coordinates; where, This is the preset scaling factor;

[0147] If the modulation symbol of the symbol-level encrypted signal point is 010, then map this symbol-level encrypted signal point to the IQ plane. coordinate;

[0148] If the modulation symbol of the symbol-level encrypted signal point is 100, then the symbol-level encrypted signal point is mapped to the IQ plane. coordinate;

[0149] If the modulation symbol of the symbol-level encrypted signal point is 110, then map this symbol-level encrypted signal point to the IQ plane. coordinate;

[0150] If the modulation symbol of the symbol-level encrypted signal point is 101, then map this symbol-level encrypted signal point to the IQ plane. coordinate;

[0151] If the modulation symbol of the symbol-level encrypted signal point is 011, then map this symbol-level encrypted signal point to the IQ plane. coordinate;

[0152] If the modulation symbol of the symbol-level encrypted signal point is 111, then map this symbol-level encrypted signal point to the IQ plane. coordinate.

[0153] When probabilistic shaping is combined with constellation design, system performance can be improved by optimizing the constellation geometry. High-probability points are concentrated near the origin within a unit circle, while low-probability points are expanded outwards, thereby minimizing transmission power and maximizing energy efficiency. Therefore, the geometric principle of the optimal regular hexagon under a fixed minimum Euclidean distance is used to optimize the overall constellation gain. The specific variations and derivation of the constellation diagram are as follows... Figure 4 As shown, Figure 4 The left side shows the IQ plane representation of signal points in a conventional rectangular constellation. After mapping this to an asymmetric polygon constellation, we obtain... Figure 4 The IQ plane display of the newly generated constellation signal points on the right; further analysis shows that from the rectangular constellation to the newly generated constellation, it can be seen that the edge signal points composed of 8 constellation points in the traditional 8-point constellation diagram gradually shrink into the middle area, making the constellation diagram gradually tend to be circular. This can further expand the effective area of ​​the constellation diagram and improve the central concentration of constellation points with the same minimum Euclidean distance.

[0154] To evaluate the performance of the constellation design proposed in this embodiment, we performed numerical analysis based on the CFM evaluation criteria.

[0155] ,

[0156] in, This indicates the assessment results of the zodiac sign. Indicates constellations, This represents the square of the minimum Euclidean distance between constellation points. This represents the average constellation power. It can be calculated that the CFM of the proposed 8-point probabilistic constellation with symbol-level chaotic labels is 0.207 higher than that of the traditional rectangular 8QAM.

[0157] Specific constellation charts and their probability distributions are as follows: Figure 5 As shown. Figure 5(a) and 5(b) show constellation diagrams with eight signal points and their probability distributions after applying symbol-level chaotic labels, where probability represents the probability. From Figure 5 As can be seen, the proposed scheme effectively reduces the probability distribution of signal points with a high number of "1"s—the probability decreases as the number of "1"s in a signal point increases. This not only effectively reduces signal power but also improves overall system performance.

[0158] In step S5, in this embodiment, the 6th decimal place of the Y and Z chaotic sequences is selected to generate the sequence. , Then the sequence and Sort the matrices in ascending order, then multiply them by their inverses to generate the first scrambled square matrix. Second Scrambled Array The orders are the number of subcarriers and the number of symbols, respectively.

[0159] The first scrambling array Second Scrambled Array It can be obtained through the following formula:

[0160] ,

[0161] in, This indicates a modulo operation. This is an ascending sorting function. This represents the second chaotic sequence after the modulo expansion. This represents the third chaotic sequence after the extended modulo operation.

[0162] In step S6, the first scrambling matrix is ​​used. Second Scrambled Array The 8QAM constellation is scrambled to obtain an 8QAM scrambled signal, including:

[0163] Obtain the first scrambling array respectively Second Scrambled Array The position of element 1 in the sequence yields the first scrambled sequence. Second scrambled sequence ;

[0164] Using the first scrambling sequence Second scrambled sequence The 8QAM constellation is scrambled to obtain the 8QAM scrambled signal:

[0165] ,

[0166] in, Represents the 8QAM constellation. This indicates the 8QAM scrambling signal.

[0167] To verify the effectiveness of the probabilistic shaping encryption method based on symbol-level chaotic labels proposed in this embodiment, based on Figure 6 The experimental setup shown, based on a 7-core fiber, was used for experiments. The transmitted data was generated offline in MATLAB as a pseudo-random binary sequence (PRBS). Symbol-level chaotic labeling was used to compress 16QAM into 8QAM. For the OFDM configuration, 256 subcarriers, 256 cyclic prefix (CP) points, and 1024 IFFT points were used. The modulated signal was fed into an arbitrary waveform generator (AWG) and converted into an analog waveform at a sampling rate of 20 GSa / s. The analog signal was linearly amplified by an electrical amplifier (EA) and then drove a Mach-Zehnder modulator (MZM) for electro-optic modulation, along with a 1550 nm continuous-wave optical carrier from a laser source with a linewidth less than 100 kHz. The modulated optical signal was amplified by an erbium-doped fiber amplifier (EDFA) and split into seven paths by an optical coupler (OC). The seven optical streams were then transmitted into a 2 km long 7-core fiber via a fan-in device. After transmission, the seven cores were demultiplexed into a single-mode fiber via a fan-out device. At the receiving end, a variable optical attenuator (VOA) is used to adjust the received optical power. Signal detection is performed by a photodiode (PD). The electrical signal is then digitized by a mixed-signal oscilloscope (MSO) operating at 50 GSa / s, and finally demodulated by an offline digital signal processor to recover the original data.

[0168] To verify the performance of the high-security PS-16-8QAM mapping scheme based on symbol-level chaotic labels, this embodiment uses MATLAB simulation software to conduct experimental simulations of traditional 16QAM, 8QAM, and the proposed PS-16-8QAM signal based on symbol-level chaotic labels. A Gaussian white noise channel was used in the simulation, and the resulting curves showing the change in bit error rate as a function of signal-to-noise ratio are shown below. Figure 7 As shown, it is evident that our proposed probabilistic shaping method based on symbol-level chaotic labels outperforms conventional uniformly distributed signal transmission. Therefore, the probabilistic shaping mapping method based on symbol-level chaotic labels can reduce the bit error rate of the transmission system and improve its transmission performance.

[0169] This embodiment investigates the sensitivity of initial parameters to a three-dimensional chaotic model. The transmission performance of a PS-16-8QAM encrypted signal was analyzed by slightly perturbing the initial values. The three-dimensional chaotic system exhibits high sensitivity—small parameter changes cause significant divergence in its trajectory. Figure 8 As shown, when the initial parameter deviation reaches At the order of magnitude, BER rises sharply to about 0.5; in contrast, Even deviations of a larger magnitude did not cause a further significant deterioration in the BER. Other system parameters a, b, c, and d also exhibited similar characteristics. The key space of the three-dimensional chaotic model is defined by the set (x, y, z, a, b, c, d). Based on this configuration, the key space can be calculated to reach 10¹. 05 The sheer size of the key space significantly enhances the system's security.

[0170] Example 2

[0171] Based on the same inventive concept as Embodiment 1, this embodiment of the invention discloses a probabilistic shaping decryption method based on symbol-level chaotic labels, with reference to... Figure 1 As shown, the specific steps include the following:

[0172] S1, after removing the cyclic prefix of the received data, perform a Fourier transform to obtain the 8QAM scrambled signal;

[0173] S2, perform scrambling and restoration processing on the 8QAM scrambled signal to obtain the 8QAM constellation;

[0174] S3, perform asymmetric polygon constellation inverse mapping on the 8QAM constellation to obtain a symbol-level encrypted signal;

[0175] S4, perform symbol-level chaotic label inverse transformation on the symbol-level encrypted signal to obtain a parallel signal;

[0176] S5, the parallel signal is converted from parallel to serial to obtain the data to be transmitted.

[0177] The received data is an encrypted transmittable signal obtained using the method described in any one of Embodiment 1.

[0178] Example 3:

[0179] Based on the same inventive concept as Embodiment 1, this embodiment of the invention discloses a probabilistic shaping encryption system based on symbol-level chaotic labels, comprising:

[0180] The serial-to-parallel conversion module is used to convert the signal to be transmitted from serial to parallel to obtain a parallel signal.

[0181] The chaotic encryption module is used to: generate a first chaotic encryption sequence using a three-dimensional chaotic system. Second chaotic encryption sequence and the third chaotic encryption sequence ;

[0182] The symbol-level chaotic label conversion module is used to: utilize the first chaotic encryption sequence The parallel signal is subjected to symbol-level chaotic label conversion to obtain a symbol-level encrypted signal;

[0183] An asymmetric polygon constellation mapping module is used to: perform asymmetric polygon constellation mapping on the symbol-level encrypted signal to obtain an 8QAM constellation;

[0184] The masking processing module is used to: process the second chaotic encryption sequence. Symbol masking and subcarrier masking are performed to obtain the first scrambling matrix. ; for the third chaotic encryption sequence Symbol masking and subcarrier masking are performed to obtain the second scrambling matrix. ;

[0185] The scrambling module is used to: utilize the first scrambling array Second Scrambled Array The 8QAM constellation is scrambled to obtain the 8QAM scrambled signal;

[0186] The inverse Fourier transform and cyclic prefix addition module is used to: perform an inverse Fourier transform on the 8QAM scrambled signal and add a cyclic prefix to obtain an encrypted and transmittable signal.

[0187] The specific functions of each module described above are explained in the relevant content of the method in Embodiment 1, and will not be repeated here.

[0188] Example 4:

[0189] Based on the same inventive concept as Embodiment 2, this embodiment of the invention discloses a probabilistic shaping decryption system based on symbol-level chaotic tags, comprising:

[0190] The Fourier transform and cyclic prefix removal module is used to: remove the cyclic prefix of the received data and then perform a Fourier transform to obtain the 8QAM scrambled signal;

[0191] The scrambling and restoration processing module is used to: perform scrambling and restoration processing on the 8QAM scrambled signal to obtain an 8QAM constellation;

[0192] The asymmetric polygon constellation inverse mapping module is used to: perform asymmetric polygon constellation inverse mapping on the 8QAM constellation to obtain a symbol-level encrypted signal;

[0193] The symbol-level chaotic label inverse conversion module is used to: perform symbol-level chaotic label inverse conversion on the symbol-level encrypted signal to obtain a parallel signal;

[0194] Parallel-to-serial conversion module, used to: convert the parallel signal into a parallel-to-serial signal to obtain the data to be transmitted;

[0195] The received data is obtained by using the encrypted transmittable signal obtained by the method described in any one of Embodiment 1.

[0196] The specific functions of each module described above are explained in the relevant content of the method in Embodiment 2, and will not be repeated here.

[0197] 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.

[0198] 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.

[0199] 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.

[0200] 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.

[0201] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A symbol-level chaos tag based probabilistic shaping encryption method, characterized by, include: The signal to be transmitted is converted from serial to parallel to obtain a parallel signal; Generating a first chaotic encryption sequence using a three-dimensional chaotic system , a second chaotic encryption sequence , and a third chaotic encryption sequence ; Utilizing a first chaotic encryption sequence Performing symbol-level chaotic label switching on the parallel signals to obtain a symbol-level encrypted signal; The symbol-level encrypted signal is mapped using an asymmetric polygon constellation to obtain an 8QAM constellation; The second chaotic encryption sequence Symbol masking and subcarrier masking are performed to obtain the first scrambling matrix. ; The third chaotic encryption sequence Symbol masking and subcarrier masking are performed to obtain the second scrambling matrix. ; Using the first scrambling array Second Scrambled Array The 8QAM constellation is scrambled to obtain the 8QAM scrambled signal; After performing an inverse Fourier transform on the 8QAM scrambled signal, a cyclic prefix is ​​added to obtain an encrypted transmittable signal.

2. The probabilistic shaping encryption method based on symbol-level chaotic labels according to claim 1, characterized in that, The expression for the three-dimensional chaotic system is as follows: ， in, For state variables, These are the preset parameters for the three-dimensional chaotic system.

3. The probabilistic shaping encryption method based on symbol-level chaotic labels according to claim 1, characterized in that, The first chaotic encryption sequence is used The parallel signal is subjected to symbol-level chaotic label conversion to obtain a symbol-level encrypted signal, including: From the first chaotic encryption sequence Extract a subsequence of the same length as the parallel signal, and then perform expansion, rounding, and modulo operations on this subsequence to obtain a binary sequence. ; The parallel signal is grouped into sets of 4 bits each to obtain... Grouped bit sequences; where, This is the default value; For any bit sequence According to the preset mapping rules, it is mapped from 4 bits to 3 bits, resulting in... Group modulation symbols; where, For indexing, , Indicates the first Grouped bit sequences; For any modulation symbol From the binary sequence Extracting modulation symbols Chaos tag Obtain symbol-level encrypted signal points ;in, Indicates the first Group modulation symbols, Indicates the first Each code element-level encrypted signal point; By combining all the symbol-level encrypted signal points, we obtain the symbol-level encrypted signal. ;in, , Indicates the first Each code element-level encrypted signal point; The binary sequence It can be obtained through the following formula: ， in, This indicates a round-down operation. Indicates a modulo operation; The modulation symbol Chaos tag It can be obtained through the following formula: ， in, Represents binary sequence The Middle Each element value Represents binary sequence The Middle Each element value; The code element-level encrypted signal point It can be obtained through the following formula: ， in, Indicates modulation symbol The first bit value, Indicates modulation symbol The second bit value, Indicates modulation symbol The third bit value.

4. The probabilistic shaping encryption method based on symbol-level chaotic labels according to claim 3, characterized in that, For any bit sequence According to the preset mapping rules, it is mapped from 4 bits to 3 bits, including: If the bit sequence If it is 0000 or 0011, convert it to 000 to obtain the modulation symbol. ; If the bit sequence If it is 0001 or 1100, convert it to 001 to obtain the modulation symbol. ; If the bit sequence If it is 0010 or 1101, convert it to 010 to obtain the modulation symbol. ; If the bit sequence If the value is 1000 or 1011, convert it to 100 to obtain the modulation symbol. ; If the bit sequence If the value is 1001 or 0111, convert it to 110 to obtain the modulation symbol. ; If the bit sequence If the value is 0100 or 0101, convert it to 101 to obtain the modulation symbol. ; If the bit sequence If the value is 0110 or 1010, convert it to 011 to obtain the modulation symbol. ; If the bit sequence If it is 1111 or 1110, convert it to 111 to obtain the modulation symbol. .

5. The probabilistic shaping encryption method based on symbol-level chaotic labels according to claim 1, characterized in that, The asymmetric polygon constellation mapping of the symbol-level encrypted signal to obtain an 8QAM constellation includes: By traversing all symbol-level encrypted signal points in the symbol-level encrypted signal, and performing the following judgments, the 8QAM constellation is obtained: If the modulation symbol of the symbol-level encrypted signal point is 000, then map this symbol-level encrypted signal point to the IQ plane. coordinate; If the modulation symbol of the symbol-level encrypted signal point is 001, then the symbol-level encrypted signal point is mapped to the IQ plane. Coordinates; where, This is the preset scaling factor; If the modulation symbol of the symbol-level encrypted signal point is 010, then map this symbol-level encrypted signal point to the IQ plane. coordinate; If the modulation symbol of the symbol-level encrypted signal point is 100, then the symbol-level encrypted signal point is mapped to the IQ plane. coordinate; If the modulation symbol of the symbol-level encrypted signal point is 110, then map this symbol-level encrypted signal point to the IQ plane. coordinate; If the modulation symbol of the symbol-level encrypted signal point is 101, then map this symbol-level encrypted signal point to the IQ plane. coordinate; If the modulation symbol of the symbol-level encrypted signal point is 011, then map this symbol-level encrypted signal point to the IQ plane. coordinate; If the modulation symbol of the symbol-level encrypted signal point is 111, then map this symbol-level encrypted signal point to the IQ plane. coordinate.

6. The probabilistic shaping encryption method based on symbol-level chaotic labels according to claim 1, characterized in that, The first scrambling array Second Scrambled Array It can be obtained through the following formula: ， in, This indicates a modulo operation. This is an ascending sorting function. This represents the second chaotic sequence after the modulo expansion. This represents the third chaotic sequence after the extended modulo operation.

7. The probabilistic shaping encryption method based on symbol-level chaotic labels according to claim 1, characterized in that, The first scrambling array is used Second Scrambled Array The 8QAM constellation is scrambled to obtain an 8QAM scrambled signal, including: Obtain the first scrambling array respectively Second Scrambled Array The position of element 1 in the sequence yields the first scrambled sequence. Second scrambled sequence ; Using the first scrambling sequence Second scrambled sequence The 8QAM constellation is scrambled to obtain the 8QAM scrambled signal; The 8QAM scrambling signal is obtained using the following formula: ， in, Represents the 8QAM constellation. This indicates the 8QAM scrambling signal.

8. A probabilistic shaping decryption method based on symbol-level chaotic labels, characterized in that, include: After removing the cyclic prefix from the received data, a Fourier transform is performed to obtain the 8QAM scrambled signal; The scrambled 8QAM signal is scrambled and restored to obtain an 8QAM constellation; The 8QAM constellation is subjected to asymmetric polygon constellation inverse mapping to obtain a symbol-level encrypted signal; The symbol-level encrypted signal is subjected to symbol-level chaotic label inverse conversion to obtain a parallel signal; The parallel signal is converted from parallel to serial to obtain the data to be transmitted; The received data is obtained by the method described in any one of claims 1 to 7, which is an encrypted transmittable signal.

9. A probabilistic shaping encryption system based on symbol-level chaotic labels, characterized in that, include: The serial-to-parallel conversion module is used to convert the signal to be transmitted from serial to parallel to obtain a parallel signal. The chaotic encryption module is used to: generate a first chaotic encryption sequence using a three-dimensional chaotic system. Second chaotic encryption sequence and the third chaotic encryption sequence ; The symbol-level chaotic label conversion module is used to: utilize the first chaotic encryption sequence The parallel signal is subjected to symbol-level chaotic label conversion to obtain a symbol-level encrypted signal; An asymmetric polygon constellation mapping module is used to: perform asymmetric polygon constellation mapping on the symbol-level encrypted signal to obtain an 8QAM constellation; The masking processing module is used to: process the second chaotic encryption sequence. Symbol masking and subcarrier masking are performed to obtain the first scrambling matrix. ; The third chaotic encryption sequence Symbol masking and subcarrier masking are performed to obtain the second scrambling matrix. ; The scrambling module is used to: utilize the first scrambling array Second Scrambled Array The 8QAM constellation is scrambled to obtain the 8QAM scrambled signal; The inverse Fourier transform and cyclic prefix addition module is used to: perform an inverse Fourier transform on the 8QAM scrambled signal and add a cyclic prefix to obtain an encrypted and transmittable signal.

10. A probabilistic shaping decryption system based on symbol-level chaotic labels, characterized in that, include: The Fourier transform and cyclic prefix removal module is used to: remove the cyclic prefix of the received data and then perform a Fourier transform to obtain the 8QAM scrambled signal; The scrambling and restoration processing module is used to: perform scrambling and restoration processing on the 8QAM scrambled signal to obtain an 8QAM constellation; The asymmetric polygon constellation inverse mapping module is used to: perform asymmetric polygon constellation inverse mapping on the 8QAM constellation to obtain a symbol-level encrypted signal; The symbol-level chaotic label inverse conversion module is used to: perform symbol-level chaotic label inverse conversion on the symbol-level encrypted signal to obtain a parallel signal; Parallel-to-serial conversion module, used to: convert the parallel signal into a parallel-to-serial signal to obtain the data to be transmitted; The received data is obtained by the method described in any one of claims 1 to 7, which is an encrypted transmittable signal.

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