An Orthogonal Frequency Division Multiplexing Transmission Method and System Based on Probabilistic Shaping

Abstract

This invention discloses an orthogonal frequency division multiplexing (OFDM) transmission method and system based on probabilistic shaping, comprising: grouping constellation points according to transmit power to obtain symbol modes; constructing a mapping relationship between index bits and modulation strategies according to a set mapping probability to obtain the mode allocation table; dividing the input raw bits into an index bit sequence and a data bit sequence, querying the preset mode allocation table according to the index bit sequence to obtain the modulation strategy, and performing constellation mapping on the data bits according to the modulation strategy to generate constellation points; mapping the constellation points onto subcarriers to generate OFDM symbol blocks; converting the OFDM symbol blocks into transmission signals; and recovering the transmission signals to obtain the original bits in response to receiving the transmission signals. This invention performs probabilistic shaping on constellation points in the constellation diagram, enabling high-power symbols to be allocated to fewer subcarriers, thereby improving the bit error rate during communication transmission.

Description

Technical Field

[0001] This invention belongs to the field of communication technology, specifically relating to an orthogonal frequency division multiplexing transmission method and system based on probabilistic shaping. Background Technology

[0002] With the continuous integration and development of technologies such as the Internet of Things, 5G, big data, and cloud computing, the scarcity of spectrum resources and the contradiction between data transmission energy efficiency have become core challenges restricting the performance of communication systems. Orthogonal Frequency Division Multiplexing (OFDM) improves the resistance to multipath fading and supports high-speed communication by converting high-speed serial data streams into parallel low-speed sub-data streams for transmission.

[0003] In an orthogonal frequency division multiplexing (OFDM) system based on subcarrier dual-mode index modulation, all subcarriers are modulated. Information bits are transmitted not only through the modulated subcarriers but also implicitly through the index of the activated subcarriers. Furthermore, the OFDM system utilizes two constellation modes for modulation, which can adapt to different channel conditions.

[0004] However, its bit error rate is significantly affected by the two constellation modes. The constellation point distribution of the traditional dual-mode index modulation system is fixed, and the outer ring constellation points have a high probability of error. Especially in high-order modulation, it will significantly increase the overall bit error rate. Summary of the Invention

[0005] This invention provides an orthogonal frequency division multiplexing transmission method and system based on probabilistic shaping, which performs probabilistic shaping on constellation points in the constellation diagram to allocate fewer subcarriers for high-power symbols and improve the bit error rate during communication transmission.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The first aspect of this invention provides an orthogonal frequency division multiplexing transmission method based on probabilistic shaping, comprising:

[0008] Symbol modes are obtained by grouping constellation points in the quadrature amplitude modulation constellation diagram according to the transmit power; the mode allocation table is obtained by constructing the mapping relationship between index bits and modulation strategy according to the set mapping probability; the modulation strategy is the symbol mode allocation method.

[0009] The input raw bits are divided into an index bit sequence and a data bit sequence. The modulation strategy is obtained by querying a preset mode allocation table based on the index bit sequence. The data bits are then mapped to a constellation to generate constellation points according to the modulation strategy.

[0010] The constellation points are mapped onto subcarriers to generate orthogonal frequency division multiplexing (OFDM) symbol blocks; an inverse fast Fourier transform is performed on the OFDM symbol blocks to obtain a time-domain signal sequence.

[0011] After adding a cyclic prefix to the time-domain signal sequence, a transmission signal is generated through digital-to-analog conversion, and then transmitted from the transmitter to the receiver through an optical fiber channel.

[0012] In response to receiving a transmitted signal, the original bits are recovered from the transmitted signal.

[0013] Furthermore, the symbol mode is obtained by grouping the constellation points in the quadrature amplitude modulation constellation diagram according to the transmit power, specifically including:

[0014] The formula for calculating the transmit power at each constellation point in the quadrature amplitude modulation constellation diagram is as follows:

[0015]

[0016] In the formula, P represents the transmit power of the constellation points. For the in-phase components of the constellation points, For the orthogonal components of constellation points;

[0017] The constellation points in the quadrature amplitude modulation constellation diagram are sorted according to the transmit power. The sorted constellation points are then divided to obtain symbol patterns, with each symbol pattern containing the same number of constellation points.

[0018] Furthermore, the mode allocation table is obtained by constructing a mapping relationship between index bits and modulation strategies according to the set mapping probabilities, specifically including:

[0019] The number of modulation strategies is determined based on the number of index bits. The number of symbol modes mapped within the modulation strategy and the number of modulation strategies. Calculate the total number of symbolic patterns assigned in the pattern allocation table;

[0020] The total number of allocations is divided according to the set mapping probability of the symbolic pattern to obtain the allocation number of each symbolic pattern, and the pattern allocation set of the symbolic pattern is obtained.

[0021] Generate by combining the symbol patterns within the pattern assignment set. Each modulation strategy has a unique combination of symbol modes. A mapping relationship is established between the modulation strategies and the index bits to obtain the mode allocation table.

[0022] Furthermore, the inverse fast Fourier transform is performed on the orthogonal frequency division multiplexing symbol block to obtain the time-domain signal sequence, specifically including:

[0023]

[0024] In the formula, is the time-domain signal sequence; j is the imaginary unit; N is the number of subcarriers; k is the discrete frequency index of the orthogonal frequency division multiplexing symbol block; and n is the discrete time index of the time-domain signal. For orthogonal frequency division multiplexing symbol blocks; Pi is the mathematical constant of a circle.

[0025] Furthermore, the transmitted signal is recovered to obtain the original bits, specifically including:

[0026] The received transmitted signal is amplified to compensate for transmission loss, and a filter is used to remove noise to obtain a correction signal; the correction signal is then converted from analog to digital and the cyclic prefix is ​​removed to obtain a time-domain signal sequence.

[0027] The time-domain signal sequence is converted into an orthogonal frequency division multiplexing (OFDM) symbol block using Fast Fourier Transform, and the received symbol is extracted from the OFDM symbol block.

[0028] Calculate the Euclidean distance between the received symbol and the constellation point in the quadrature amplitude modulation constellation diagram, and determine the symbol mode corresponding to the received symbol by the minimum Euclidean distance; obtain the index bit sequence by querying the preset mode allocation table according to the symbol mode allocation method.

[0029] The modulation strategy is obtained by querying the preset mode allocation table according to the index bit sequence, and the received symbols are de-encoded according to the modulation strategy to generate the data bit sequence.

[0030] The original bits are obtained by concatenating the index bit sequence and the data bit sequence.

[0031] Furthermore, the time-domain signal sequence is converted into orthogonal frequency division multiplexing (OFDM) symbol blocks using Fast Fourier Transform (FFT). The specific process is as follows:

[0032]

[0033] In the formula, is the time-domain signal sequence; j is the imaginary unit; N is the number of subcarriers; k is the discrete frequency index of the orthogonal frequency division multiplexing symbol block; and n is the discrete time index of the time-domain signal. For orthogonal frequency division multiplexing symbol blocks; Pi is the mathematical constant of a circle.

[0034] Furthermore, according to the modulation strategy, constellation demapping is performed on the received symbols to generate a data bit sequence, specifically including:

[0035] The symbol mode to which the received symbol belongs is determined by the modulation strategy. The Euclidean distance between the received symbol and the constellation points in the symbol mode is calculated. The constellation points mapped by the received symbol are selected based on the Euclidean distance, and a data bit sequence is generated through constellation demapping.

[0036] A second aspect of the present invention provides an orthogonal frequency division multiplexing transmission system based on probabilistic shaping, comprising:

[0037] The mode partitioning module is used to group constellation points in the orthogonal amplitude modulation constellation diagram according to the transmit power to obtain symbol modes; and to construct the mapping relationship between index bits and modulation strategies according to a set mapping probability to obtain the mode allocation table; wherein the modulation strategy is the allocation method of symbol modes.

[0038] The constellation mapping module divides the input raw bits into an index bit sequence and a data bit sequence. It queries a preset mode allocation table based on the index bit sequence to obtain the modulation strategy, and performs constellation mapping on the data bits according to the modulation strategy to generate constellation points.

[0039] The signal modulation module maps the constellation points onto subcarriers to generate orthogonal frequency division multiplexing (OFDM) symbol blocks; performs inverse fast Fourier transform on the OFDM symbol blocks to obtain a time-domain signal sequence; adds a cyclic prefix to the time-domain signal sequence and generates a transmission signal through digital-to-analog conversion; and transmits the transmission signal from the transmitter to the receiver through an optical fiber channel.

[0040] The signal receiving module, in response to receiving the transmitted signal, recovers the original bits from the transmitted signal.

[0041] A third aspect of the present invention provides an electronic terminal, including a processor and a storage medium; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the steps of the orthogonal frequency division multiplexing transmission method of the first aspect.

[0042] A fourth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the orthogonal frequency division multiplexing transmission method described in the first aspect.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] This invention constructs a mapping relationship between index bits and modulation strategies according to a set mapping probability to obtain the mode allocation table, queries the preset mode allocation table according to the index bit sequence to obtain the modulation strategy, performs constellation mapping on data bits according to the modulation strategy to generate constellation points, and performs probability shaping on the constellation points in the constellation diagram to make low-power constellation points appear more frequently and high-power constellation points appear less frequently, thereby improving the bit error rate in the communication transmission process. Attached Figure Description

[0045] Figure 1 This is a flowchart of the orthogonal frequency division multiplexing transmission method provided in Embodiment 1 of the present invention;

[0046] Figure 2 This is a symbol pattern grouping structure diagram provided in Embodiment 1 of the present invention;

[0047] Figure 3 (a) is a traditional constellation diagram in the prior art;

[0048] Figure 3 Inner (b) is the constellation diagram after probability shaping provided in Embodiment 1 of the present invention. Detailed Implementation

[0049] 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.

[0050] Example 1

[0051] like Figure 1 As shown, this embodiment provides an orthogonal frequency division multiplexing transmission method based on probabilistic shaping, including:

[0052] The symbol mode is obtained by grouping constellation points in the quadrature amplitude modulation constellation diagram according to the transmit power, specifically including:

[0053] The formula for calculating the transmit power at each constellation point in the quadrature amplitude modulation constellation diagram is as follows:

[0054]

[0055] In the formula, P represents the transmit power of the constellation points. For the in-phase components of the constellation points, For the orthogonal components of constellation points;

[0056] like Figure 2 As shown, the constellation points in the quadrature amplitude modulation constellation diagram are sorted according to the transmit power. The sorted constellation points are then divided to obtain symbol patterns. Each symbol pattern contains the same number of constellation points.

[0057] In this embodiment, the quadrature amplitude modulation (QAM) constellation diagram is set as a 32QAM constellation diagram, and the constellation points in the QAM constellation diagram are divided into 8 groups, each group containing 4 constellation points; specifically:

[0058] The coordinates of the constellation points in symbol pattern A are (1,1), (-1,1), (-1,-1), and (1,-1);

[0059] The coordinates of the constellation points in symbol pattern B are (1,3), (-3,1), (-1,-3), and (3,-1);

[0060] The coordinates of the constellation points in symbol pattern C are (3, 1), (1, -3), (-3, -1), and (-1, 3).

[0061] The coordinates of the constellation points in symbol pattern D are (3,3), (-3,3), (-3,-3), and (3,-3);

[0062] The coordinates of the constellation points in symbol pattern E are (1,5), (-5,1), (-1,-5) and (5,-1);

[0063] The coordinates of the constellation points in symbol pattern F are (5,1), (-1,5), (-5,-1) and (1,-5);

[0064] The coordinates of the constellation points in symbol pattern G are (3,5), (-3,5), (3,-5) and (-3,-5);

[0065] The coordinates of the constellation points in symbol pattern H are (5,3), (-5,3), (5,-3) and (-5,-3);

[0066] The mode allocation table is obtained by constructing a mapping relationship between index bits and modulation strategies according to a set mapping probability; the modulation strategy is a symbol mode allocation method; specifically including:

[0067] The number of modulation strategies is determined based on the number of index bits. The number of symbol modes mapped within the modulation strategy and the number of modulation strategies. Calculate the total number of symbolic patterns assigned in the pattern allocation table;

[0068] The mapping probabilities are obtained from Table 1. The total number of allocations is divided according to the set mapping probabilities of the symbolic patterns to obtain the allocation number of each symbolic pattern, and the pattern allocation set of the symbolic patterns is obtained.

[0069] Table 1. Mapping Probability Table of Symbol Patterns

[0070]

[0071] As shown in Table 2, the symbol patterns within the pattern assignment set are combined to generate... Each modulation strategy has a unique combination of symbol modes. A mapping relationship is established between the modulation strategies and the index bits to obtain the mode allocation table.

[0072] Table 2. Mapping relationship between modulation strategy and index bits

[0073]

[0074] In this embodiment, when the index bit is "000", all three subcarriers use symbol mode A, which is the four constellation points in the inner circle with the lowest energy. This makes the low-energy symbols appear more frequently during transmission, thereby reducing the overall average transmission power of the communication. When the index bit is "001" and "010", the subcarrier modes selected are (symbol mode A, symbol mode B, symbol mode C) and (symbol mode A, symbol mode B, and symbol mode D), respectively. While ensuring that at least one subcarrier uses a low-energy constellation, slightly higher-energy constellation points are introduced, so that the probability of the eight constellation points with energy outside the inner circle is in the second tier. When the index bit is "011", "100", etc., (symbol mode A, symbol mode C, symbol mode D) and (symbol mode A, symbol mode B, and symbol mode E) are selected accordingly. Even higher-energy constellation points are further introduced, so that they appear with a lower probability in constellation mapping, until when the index bit is "111", the highest-energy constellation subset is selected, significantly reducing the frequency of high-energy symbols.

[0075] Among the eight modulation strategies, symbol mode A appears 7 times, with a probability of approximately 29.17%; symbol modes B and C each appear 4 times, accounting for approximately 16.67%; symbol mode D appears 3 times, accounting for 12.5%; symbol modes E and F each appear 2 times, accounting for approximately 8.33%; and finally, symbol modes G and H each appear once, accounting for approximately 4.17%. This non-uniform probability distribution achieves the effect of probability shaping without complex coding by understanding the relationship between predefined index bits and subcarrier allocation patterns.

[0076] The input raw bits are divided into an index bit sequence and a data bit sequence. The modulation strategy is obtained by querying a preset mode allocation table based on the index bit sequence. The data bits are then mapped to a constellation to generate constellation points according to the modulation strategy.

[0077] The constellation points are mapped onto subcarriers to generate orthogonal frequency division multiplexing (OFDM) symbol blocks; the inverse fast Fourier transform of the OFDM symbol blocks yields the time-domain signal sequence, expressed as:

[0078]

[0079] In the formula, is the time-domain signal sequence; j is the imaginary unit; N is the number of subcarriers; k is the discrete frequency index of the orthogonal frequency division multiplexing symbol block; and n is the discrete time index of the time-domain signal. For orthogonal frequency division multiplexing symbol blocks; Pi is the mathematical constant of a circle.

[0080] After adding a cyclic prefix to the time-domain signal sequence, a transmission signal is generated through digital-to-analog conversion, and then transmitted from the transmitter to the receiver through an optical fiber channel.

[0081] In response to receiving a transmitted signal, the original bits are recovered from the transmitted signal, specifically including:

[0082] The received transmitted signal is amplified to compensate for transmission loss, and a filter is used to remove noise to obtain a correction signal; the correction signal is then converted from analog to digital and the cyclic prefix is ​​removed to obtain a time-domain signal sequence.

[0083] The time-domain signal sequence is converted into an orthogonal frequency division multiplexing (OFDM) symbol block using the Fast Fourier Transform (FFT), expressed by the following formula:

[0084]

[0085] In the formula, is the time-domain signal sequence; j is the imaginary unit; N is the number of subcarriers; k is the discrete frequency index of the orthogonal frequency division multiplexing symbol block; and n is the discrete time index of the time-domain signal. For orthogonal frequency division multiplexing symbol blocks; Pi is the mathematical constant of a circle.

[0086] The received symbols are extracted from the orthogonal frequency division multiplexing symbol block. The Euclidean distance between the received symbols and the constellation points in the orthogonal amplitude modulation constellation diagram is calculated. The symbol mode corresponding to the received symbols is determined by the minimum Euclidean distance. The index bit sequence is obtained by querying the preset mode allocation table according to the symbol mode allocation method.

[0087] The modulation strategy is obtained by querying a preset mode allocation table based on the index bit sequence. The received symbols are then de-encoded into a constellation according to the modulation strategy to generate a data bit sequence. Specifically, this includes:

[0088] The symbol mode to which the received symbol belongs is determined by the modulation strategy. The Euclidean distance between the received symbol and the constellation points in the corresponding symbol mode is calculated. The constellation points mapped to the received symbol are selected based on the Euclidean distance, and a data bit sequence is generated through constellation demapping. The index bit sequence and the data bit sequence are concatenated to obtain the original bits.

[0089] like Figure 3As shown, using the probabilistic shaping method proposed in this embodiment, the probability of each symbol mode occurring matches the set probability values ​​in Table 2. Symbol mode A, representing low-energy symbols, occurs in approximately 29.17% of cases; symbol modes B and C each account for approximately 16.67%; symbol mode D accounts for approximately 12.50%; symbol modes E and F each account for approximately 8.33%; and symbol modes G and H each account for approximately 4.17%. This result fully verifies that the subcarrier non-uniform allocation method based on index bit driving in this embodiment can achieve probabilistic shaping effects without complex coding.

[0090] Example 2

[0091] This embodiment provides an orthogonal frequency division multiplexing (OFDM) transmission system based on probabilistic shaping. The OFDM transmission system is used to execute the OFDM transmission method described in Embodiment 1. The OFDM transmission system includes:

[0092] The mode partitioning module is used to group constellation points in the orthogonal amplitude modulation constellation diagram according to the transmit power to obtain symbol modes; and to construct the mapping relationship between index bits and modulation strategies according to a set mapping probability to obtain the mode allocation table; wherein the modulation strategy is the allocation method of symbol modes.

[0093] The constellation mapping module divides the input raw bits into an index bit sequence and a data bit sequence. It queries a preset mode allocation table based on the index bit sequence to obtain the modulation strategy, and performs constellation mapping on the data bits according to the modulation strategy to generate constellation points.

[0094] The signal modulation module maps the constellation points onto subcarriers to generate orthogonal frequency division multiplexing (OFDM) symbol blocks; performs inverse fast Fourier transform on the OFDM symbol blocks to obtain a time-domain signal sequence; adds a cyclic prefix to the time-domain signal sequence and generates a transmission signal through digital-to-analog conversion; and transmits the transmission signal from the transmitter to the receiver through an optical fiber channel.

[0095] The signal receiving module, in response to receiving the transmitted signal, recovers the original bits from the transmitted signal.

[0096] The mode division module groups the constellation points in the quadrature amplitude modulation constellation diagram according to the transmit power to obtain the symbol mode, specifically including:

[0097] The formula for calculating the transmit power at each constellation point in the quadrature amplitude modulation constellation diagram is as follows:

[0098]

[0099] In the formula, P represents the transmit power of the constellation points. For the in-phase components of the constellation points, For the orthogonal components of constellation points;

[0100] The constellation points in the quadrature amplitude modulation constellation diagram are sorted according to the transmit power. The sorted constellation points are then divided to obtain symbol patterns, with each symbol pattern containing the same number of constellation points.

[0101] The mode partitioning module constructs a mapping relationship between index bits and modulation strategies according to a set mapping probability to obtain the mode allocation table, specifically including:

[0102] The number of modulation strategies is determined based on the number of index bits. The number of symbol modes mapped within the modulation strategy and the number of modulation strategies. Calculate the total number of symbolic patterns assigned in the pattern allocation table;

[0103] The total number of allocations is divided according to the set mapping probability of the symbolic pattern to obtain the allocation number of each symbolic pattern, and the pattern allocation set of the symbolic pattern is obtained.

[0104] Randomly combine and generate symbols from the pattern assignment set. Each modulation strategy has a unique combination of symbol modes. A mapping relationship is established between the modulation strategies and the index bits to obtain the mode allocation table, which means that there is a one-to-one correspondence between the modulation strategies and the index bits.

[0105] Example 3

[0106] This embodiment provides an electronic terminal, including a processor and a storage medium; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the steps of the orthogonal frequency division multiplexing transmission method described in Embodiment 1.

[0107] Example 4

[0108] This embodiment provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the orthogonal frequency division multiplexing transmission method described in Embodiment 1.

[0109] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application 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.

[0110] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. 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... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0111] 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.

[0112] 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.

[0113] 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. An orthogonal frequency division multiplexing transmission method based on probabilistic shaping, characterized in that, include: The symbol pattern is obtained by grouping the constellation points in the quadrature amplitude modulation constellation diagram according to the transmit power. The mode allocation table is obtained by constructing the mapping relationship between index bits and modulation strategies according to the set mapping probabilities, specifically including: The number of modulation strategies is determined based on the number of index bits. The number of symbol modes mapped within the modulation strategy and the number of modulation strategies. Calculate the total number of symbolic patterns assigned in the pattern allocation table; The total number of allocations is divided according to the set mapping probability of the symbolic pattern to obtain the allocation number of each symbolic pattern, and the pattern allocation set of the symbolic pattern is obtained. The symbol modes within the mode allocation set are combined to generate M modulation strategies. A mapping relationship is set between the modulation strategies and index bits to obtain the mode allocation table; the modulation strategy is the allocation method of the symbol modes. The input raw bits are divided into an index bit sequence and a data bit sequence. The modulation strategy is obtained by querying a preset mode allocation table based on the index bit sequence. The data bits are then mapped to a constellation to generate constellation points according to the modulation strategy. The constellation points are mapped onto subcarriers to generate orthogonal frequency division multiplexing (OFDM) symbol blocks; an inverse fast Fourier transform is performed on the OFDM symbol blocks to obtain a time-domain signal sequence. After adding a cyclic prefix to the time-domain signal sequence, a transmission signal is generated through digital-to-analog conversion, and then transmitted from the transmitter to the receiver through an optical fiber channel. In response to receiving a transmitted signal, the original bits are recovered from the transmitted signal.

2. The orthogonal frequency division multiplexing transmission method according to claim 1, characterized in that, The symbol mode is obtained by grouping constellation points in the quadrature amplitude modulation constellation diagram according to the transmit power, specifically including: The formula for calculating the transmit power at each constellation point in the quadrature amplitude modulation constellation diagram is as follows: ； In the formula, P represents the transmit power of the constellation points. For the in-phase components of the constellation points, For the orthogonal components of constellation points; The constellation points in the quadrature amplitude modulation constellation diagram are sorted according to the transmit power. The sorted constellation points are then divided to obtain symbol patterns, with each symbol pattern containing the same number of constellation points.

3. The orthogonal frequency division multiplexing transmission method according to claim 1, characterized in that, The inverse fast Fourier transform of the orthogonal frequency division multiplexing (OFDM) symbol block yields a time-domain signal sequence, specifically including: ； In the formula, is the time-domain signal sequence; j is the imaginary unit; N is the number of subcarriers; k is the discrete frequency index of the orthogonal frequency division multiplexing symbol block; and n is the discrete time index of the time-domain signal. is an orthogonal frequency division multiplexing symbol block; π is the mathematical constant pi.

4. The orthogonal frequency division multiplexing transmission method according to claim 1, characterized in that, The process of recovering the transmitted signal to obtain the original bits includes: The received transmitted signal is amplified to compensate for transmission loss, and a filter is used to remove noise to obtain a correction signal; the correction signal is then converted from analog to digital and the cyclic prefix is ​​removed to obtain a time-domain signal sequence. The time-domain signal sequence is converted into an orthogonal frequency division multiplexing (OFDM) symbol block using Fast Fourier Transform, and the received symbol is extracted from the OFDM symbol block. Calculate the Euclidean distance between the received symbol and the constellation point in the quadrature amplitude modulation constellation diagram, and determine the symbol mode corresponding to the received symbol by the minimum Euclidean distance; obtain the index bit sequence by querying the preset mode allocation table according to the symbol mode allocation method. The modulation strategy is obtained by querying the preset mode allocation table according to the index bit sequence, and the received symbols are de-encoded according to the modulation strategy to generate the data bit sequence. The original bits are obtained by concatenating the index bit sequence and the data bit sequence.

5. The orthogonal frequency division multiplexing transmission method according to claim 4, characterized in that, The process of converting a time-domain signal sequence into an orthogonal frequency division multiplexing (OFDM) symbol block using Fast Fourier Transform is as follows: ； In the formula, is the time-domain signal sequence; j is the imaginary unit; N is the number of subcarriers; k is the discrete frequency index of the orthogonal frequency division multiplexing symbol block; and n is the discrete time index of the time-domain signal. is an orthogonal frequency division multiplexing symbol block; π is the mathematical constant pi.

6. The orthogonal frequency division multiplexing transmission method according to claim 4, characterized in that, According to the modulation strategy, constellation demapping is performed on the received symbols to generate a data bit sequence, specifically including: The symbol mode to which the received symbol belongs is determined by the modulation strategy. The Euclidean distance between the received symbol and the constellation points in the symbol mode is calculated. The constellation points mapped by the received symbol are selected based on the Euclidean distance, and a data bit sequence is generated through constellation demapping.

7. An orthogonal frequency division multiplexing transmission system based on probabilistic shaping, characterized in that, include: The mode division module is used to group constellation points in the quadrature amplitude modulation constellation diagram according to the transmit power to obtain the symbol mode; A mode allocation table is obtained by constructing a mapping relationship between index bits and modulation strategies according to a set mapping probability; the modulation strategy is a symbol mode allocation method. The constellation mapping module divides the input raw bits into an index bit sequence and a data bit sequence. It queries a preset mode allocation table based on the index bit sequence to obtain the modulation strategy, and performs constellation mapping on the data bits according to the modulation strategy to generate constellation points. The signal modulation module maps the constellation points onto subcarriers to generate orthogonal frequency division multiplexing (OFDM) symbol blocks; performs inverse fast Fourier transform on the OFDM symbol blocks to obtain a time-domain signal sequence; adds a cyclic prefix to the time-domain signal sequence and generates a transmission signal through digital-to-analog conversion; and transmits the transmission signal from the transmitter to the receiver through an optical fiber channel. The signal receiving module, in response to receiving the transmitted signal, recovers the transmitted signal to obtain the original bits; The mode division module constructs a mapping relationship between index bits and modulation strategies according to a set mapping probability to obtain a mode allocation table, specifically including: The number of modulation strategies is determined based on the number of index bits. The number of symbol modes mapped within the modulation strategy and the number of modulation strategies. Calculate the total number of symbolic patterns assigned in the pattern allocation table; The total number of allocations is divided according to the set mapping probability of the symbolic pattern to obtain the allocation number of each symbolic pattern, and the pattern allocation set of the symbolic pattern is obtained. The symbol modes within the mode allocation set are combined to generate M modulation strategies, and a mapping relationship is set between the modulation strategies and the index bits to obtain the mode allocation table.

8. An electronic terminal, comprising a processor and a storage medium; said storage medium being used to store instructions; characterized in that, The processor is configured to operate according to the instructions to perform the steps of the orthogonal frequency division multiplexing transmission method according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the orthogonal frequency division multiplexing transmission method according to any one of claims 1 to 6.

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