Orthogonal frequency division multiplexing transmission method and system based on probabilistic shaping

Abstract

The invention discloses an orthogonal frequency division multiplexing transmission method and system based on probability shaping. The method comprises the following steps: grouping constellation points according to transmitting power to obtain a symbol mode; constructing a mapping relation between index bits and modulation strategies according to a set mapping probability to obtain the mode distribution table; the method comprises the following steps: dividing an input original bit into an index bit sequence and a data bit sequence, querying a preset mode allocation table according to the index bit sequence to obtain a modulation strategy, and performing constellation mapping on the data bit according to the modulation strategy to generate a constellation point; mapping the constellation points to a subcarrier to generate an orthogonal frequency division multiplexing symbol block; converting the orthogonal frequency division multiplexing symbol block into a transmission signal; in response to the received transmission signal, the transmission signal is recovered to obtain the original bit, probability shaping is performed on the constellation points in the constellation diagram, so that a high-power symbol is allocated with fewer subcarriers, and the bit error rate in the communication transmission process is improved.

Description

Technical Field

[0001] The present invention belongs to the field of communication technology, and in particular relates to an orthogonal frequency division multiplexing transmission method and system based on probability shaping. Background Art

[0002] With the continuous convergence and development of technologies such as the Internet of Things, 5G, big data, and cloud computing, the conflict between spectrum scarcity and data transmission energy efficiency has become a core challenge constraining the performance of communication systems. Orthogonal Frequency Division Multiplexing (OFDM) converts high-speed serial data streams into parallel, lower-speed sub-data streams for transmission, improving resilience to multipath fading and supporting high-speed communications.

[0003] In an OFDM system based on subcarrier dual-mode index modulation, all subcarriers are modulated, and information bits are transmitted not only through the modulated subcarriers but also implicitly through the index of the activated subcarriers. At the same time, the OFDM system also uses 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 error probability of the outer constellation points is high, especially in high-order modulation, which will significantly increase the overall bit error rate. Summary of the Invention

[0005] The present invention provides an orthogonal frequency division multiplexing transmission method and system based on probability shaping, which performs probability shaping on constellation points in a constellation diagram, allocates fewer subcarriers to high-power symbols, and improves the bit error rate during communication transmission.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A first aspect of the present invention provides an orthogonal frequency division multiplexing transmission method based on probability shaping, comprising:

[0008] The constellation points in the orthogonal amplitude modulation constellation diagram are grouped according to the transmission power to obtain the symbol mode; the mapping relationship between the index bit and the modulation strategy is constructed according to the set mapping probability to obtain the mode allocation table; the modulation strategy is the allocation method of the symbol mode;

[0009] Divide the input original bits into an index bit sequence and a data bit sequence, query a preset mode allocation table according to the index bit sequence to obtain a modulation strategy, and perform constellation mapping on the data bits according to the modulation strategy to generate constellation points;

[0010] Mapping the constellation points onto subcarriers to generate orthogonal frequency division multiplexing symbol blocks; performing inverse fast Fourier transform on the orthogonal frequency division multiplexing 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 the transmission signal is sent from the transmitter to the receiver through the optical fiber channel;

[0012] In response to receiving the transmission signal, the transmission signal is restored to obtain the original bits.

[0013] Furthermore, the constellation points in the orthogonal amplitude modulation constellation diagram are grouped according to the transmit power to obtain a symbol pattern, specifically including:

[0014] Calculate the transmit power of each constellation point in the quadrature amplitude modulation constellation diagram. The expression formula is:

[0015]

[0016] In the formula, P is the transmit power of the constellation point, is the in-phase component of the constellation point, are the orthogonal components of the constellation points;

[0017] The constellation points in the orthogonal amplitude modulation constellation diagram are sorted according to the transmission power, and the sorted constellation points are divided to obtain symbol patterns, and each symbol pattern contains the same number of constellation points.

[0018] Furthermore, constructing a mapping relationship between index bits and modulation strategies according to the set mapping probability to obtain the mode allocation table specifically includes:

[0019] Determine the number of modulation strategies based on the number of index bits , by the number of symbol mode mappings within the modulation strategy and the number of modulation strategies Calculate the total number of symbol patterns allocated in the pattern allocation table;

[0020] Dividing the total allocation quantity according to the set mapping probability of the symbol mode to obtain the allocation quantity of each symbol mode, and obtaining a mode allocation set of the symbol mode;

[0021] Combine the symbol patterns in the pattern allocation set to generate modulation strategies, each modulation strategy corresponds to a different symbol mode combination, and a mapping relationship is set between the modulation strategy and the index bit to obtain the mode allocation table.

[0022] Furthermore, performing an inverse fast Fourier transform on the orthogonal frequency division multiplexing symbol block to obtain a time domain signal sequence specifically includes:

[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 OFDM symbol block, and n is the discrete time index of the time domain signal; is an orthogonal frequency division multiplexing symbol block; is pi.

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

[0026] The received transmission 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 converted into a digital form and the cyclic prefix is ​​removed to obtain a time domain signal sequence;

[0027] Convert the time domain signal sequence into an orthogonal frequency division multiplexing symbol block by fast Fourier transform, and extract the received symbol from the orthogonal frequency division multiplexing symbol block;

[0028] Calculating the Euclidean distance between the received symbol and the constellation point in the orthogonal amplitude modulation constellation diagram, and determining the symbol mode corresponding to the received symbol based on the minimum Euclidean distance; querying a preset mode allocation table according to the allocation method of the symbol mode to obtain an index bit sequence;

[0029] Querying a preset mode allocation table according to the index bit sequence to obtain a modulation strategy, and performing constellation demapping on the received symbols according to the modulation strategy to generate a data bit sequence;

[0030] The index bit sequence and the data bit sequence are concatenated to obtain the original bits.

[0031] Furthermore, the time domain signal sequence is converted into an orthogonal frequency division multiplexing symbol block through fast Fourier transform. 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 OFDM symbol block, and n is the discrete time index of the time domain signal; is an orthogonal frequency division multiplexing symbol block; is pi.

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

[0035] The modulation strategy determines the symbol mode to which the received symbol belongs, calculates the Euclidean distance between the received symbol and the constellation point in the symbol mode to which it belongs, selects the constellation point to which the received symbol is mapped based on the Euclidean distance, and generates a data bit sequence through constellation demapping.

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

[0037] A mode division module is configured to group constellation points in a quadrature amplitude modulation constellation diagram according to transmit power to obtain symbol modes; construct a mapping relationship between index bits and modulation strategies according to set mapping probabilities to obtain the mode allocation table; the modulation strategy is a way of allocating symbol modes;

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

[0039] a signal modulation module that maps the constellation points onto subcarriers to generate orthogonal frequency division multiplexing symbol blocks; performs an inverse fast Fourier transform on the orthogonal frequency division multiplexing symbol blocks to obtain a time domain signal sequence; adds a cyclic prefix to the time domain signal sequence and then generates a transmission signal through digital-to-analog conversion; and transmits the transmission signal from a transmitting end to a receiving end via an optical fiber channel;

[0040] The signal receiving module recovers the transmission signal to obtain the original bits in response to receiving the transmission signal.

[0041] The third aspect of the present invention provides an electronic terminal, comprising 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 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 present invention has the following beneficial effects:

[0044] The present 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 probabilistically shapes the constellation points in the constellation diagram so that low-power constellation points appear more frequently and high-power constellation points appear less frequently, thereby improving the bit error rate during communication transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a flow chart of the orthogonal frequency division multiplexing transmission method provided in Example 1 of the present invention;

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

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

[0048] Figure 3 Inner (b) is the constellation diagram after probability shaping provided by embodiment 1 of the present invention. DETAILED DESCRIPTION

[0049] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended 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 probability shaping, including:

[0052] The constellation points in the quadrature amplitude modulation constellation diagram are grouped according to the transmit power to obtain a symbol pattern, specifically including:

[0053] Calculate the transmit power of each constellation point in the quadrature amplitude modulation constellation diagram. The expression formula is:

[0054]

[0055] In the formula, P is the transmit power of the constellation point, is the in-phase component of the constellation point, are the orthogonal components of the constellation points;

[0056] like Figure 2 As shown, the constellation points in the orthogonal amplitude modulation constellation diagram are sorted according to the transmission power, and the sorted constellation points are divided to obtain symbol patterns, and the number of constellation points contained in each symbol pattern is the same.

[0057] In this embodiment, the quadrature amplitude modulation constellation diagram is set to a 32QAM constellation diagram, and the constellation points in the quadrature amplitude modulation 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 mode 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 the set mapping probability; the modulation strategy is a way of allocating symbol modes; specifically including:

[0067] Determine the number of modulation strategies based on the number of index bits , by the number of symbol mode mappings within the modulation strategy and the number of modulation strategies Calculate the total number of symbol patterns allocated in the pattern allocation table;

[0068] Obtain mapping probabilities from Table 1, divide the total allocation quantity according to the set mapping probabilities of the symbol modes to obtain allocation quantities for the respective symbol modes, and obtain a mode allocation set for the symbol modes;

[0069] Table 1, symbol pattern mapping probability table

[0070]

[0071] As shown in Table 2, the symbol patterns in the pattern allocation set are combined to generate modulation strategies, each modulation strategy corresponds to a different symbol mode combination, and a mapping relationship is set between the modulation strategy and the index bit to obtain the mode allocation table.

[0072] Table 2, mapping relationship between modulation strategy and index bit

[0073]

[0074] In this embodiment, when the index bit is "000," all three subcarriers use symbol mode A, i.e., the four inner-circle constellation points with the lowest energy. This allows low-energy symbols to appear more frequently during transmission, thereby reducing the overall average transmit power of the communication. When the index bits are "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, reducing the probability of the eight constellation points outside the inner circle to the second tier. When the index bits are "011," "100," and other patterns, (symbol mode A, symbol mode C, symbol mode D) and (symbol mode A, symbol mode B, and symbol mode E) are selected accordingly. Constellation points with higher energy are further introduced, causing them to appear with even lower probabilities in the constellation mapping. When the index bit is "111," all constellation points are selected from the highest-energy constellation subset, 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 mode B and symbol mode C appear 4 times each, accounting for approximately 16.67%; symbol mode D appears 3 times, accounting for 12.5%; symbol mode E and symbol mode F appear 2 times each, accounting for approximately 8.33%; finally, symbol mode G and symbol mode H appear 1 time, accounting for approximately 4.17%. This non-uniform probability distribution achieves the effect of probability shaping without complex coding through the relationship between the predefined index bits and the subcarrier allocation pattern.

[0076] Divide the input original bits into an index bit sequence and a data bit sequence, query a preset mode allocation table according to the index bit sequence to obtain a modulation strategy, and perform constellation mapping on the data bits according to the modulation strategy to generate constellation points;

[0077] The constellation points are mapped onto subcarriers to generate orthogonal frequency division multiplexing symbol blocks (abbreviated as OFDM subblocks). The orthogonal frequency division multiplexing symbol blocks are subjected to inverse fast Fourier transform to obtain a time domain signal sequence, which is expressed as follows:

[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 OFDM symbol block, and n is the discrete time index of the time domain signal; is an orthogonal frequency division multiplexing symbol block; is pi.

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

[0081] In response to receiving the transmission signal, recovering the transmission signal to obtain original bits specifically includes:

[0082] The received transmission 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 converted into a digital form 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 symbol block through fast Fourier transform, and the expression formula is:

[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 OFDM symbol block, and n is the discrete time index of the time domain signal; is an orthogonal frequency division multiplexing symbol block; is pi.

[0086] Extracting a received symbol from an orthogonal frequency division multiplexing symbol block, calculating the Euclidean distance between the received symbol and a constellation point in an orthogonal amplitude modulation constellation diagram, and determining the symbol mode corresponding to the received symbol based on the minimum Euclidean distance; and obtaining an index bit sequence by querying a preset mode allocation table based on the allocation method of the symbol mode;

[0087] The modulation strategy is obtained by querying a preset mode allocation table according to the index bit sequence, and constellation decoding is performed on the received symbols according to the modulation strategy to generate a data bit sequence, specifically including:

[0088] The modulation strategy determines the symbol mode to which the received symbol belongs. The Euclidean distance between the received symbol and the constellation point in the symbol mode is calculated. The constellation point to which the received symbol is mapped is selected based on the Euclidean distance. The data bit sequence is then 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 probability shaping method proposed in this embodiment, the probability of each symbol pattern occurring is consistent with the set probability values ​​in Table 2. Symbol pattern A has a low-energy symbol occurrence rate of approximately 29.17%, symbol pattern B and symbol pattern C each have a low-energy symbol occurrence rate of approximately 16.67%, symbol pattern D has a low-energy symbol occurrence rate of approximately 12.50%, symbol pattern E and symbol pattern F each have a low-energy symbol occurrence rate of approximately 8.33%, and symbol pattern G and symbol pattern H each have a low-energy symbol occurrence rate of approximately 4.17%. This result fully verifies that the index bit-driven non-uniform subcarrier allocation method in this embodiment can achieve a probability shaping effect without the need for complex coding.

[0090] Example 2

[0091] This embodiment provides an orthogonal frequency division multiplexing transmission system based on probability shaping. The orthogonal frequency division multiplexing transmission system is used to perform the orthogonal frequency division multiplexing transmission method described in Example 1. The orthogonal frequency division multiplexing transmission system includes:

[0092] A mode division module is configured to group constellation points in a quadrature amplitude modulation constellation diagram according to transmit power to obtain symbol modes; construct a mapping relationship between index bits and modulation strategies according to set mapping probabilities to obtain the mode allocation table; the modulation strategy is a way of allocating symbol modes;

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

[0094] a signal modulation module that maps the constellation points onto subcarriers to generate orthogonal frequency division multiplexing symbol blocks; performs an inverse fast Fourier transform on the orthogonal frequency division multiplexing symbol blocks to obtain a time domain signal sequence; adds a cyclic prefix to the time domain signal sequence and then generates a transmission signal through digital-to-analog conversion; and transmits the transmission signal from a transmitting end to a receiving end via an optical fiber channel;

[0095] The signal receiving module recovers the transmission signal to obtain the original bits in response to receiving the transmission signal.

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

[0097] Calculate the transmit power of each constellation point in the quadrature amplitude modulation constellation diagram. The expression formula is:

[0098]

[0099] In the formula, P is the transmit power of the constellation point, is the in-phase component of the constellation point, are the orthogonal components of the constellation points;

[0100] The constellation points in the orthogonal amplitude modulation constellation diagram are sorted according to the transmission power, and the sorted constellation points are divided to obtain symbol patterns, and each symbol pattern contains the same number of constellation points.

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

[0102] Determine the number of modulation strategies based on the number of index bits , by the number of symbol mode mappings within the modulation strategy and the number of modulation strategies Calculate the total number of symbol patterns allocated in the pattern allocation table;

[0103] Dividing the total allocation quantity according to the set mapping probability of the symbol mode to obtain the allocation quantity of each symbol mode, and obtaining a mode allocation set of the symbol mode;

[0104] Generate random combinations of symbol patterns within the pattern allocation set modulation strategies, each modulation strategy corresponds to a different symbol mode combination, and a mapping relationship is set between the modulation strategy and the index bit to obtain the mode allocation table, that is, the modulation strategy and the index bit are in one-to-one correspondence.

[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 Example 1.

[0107] Example 4

[0108] This embodiment provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the orthogonal frequency division multiplexing transmission method described in Embodiment 1 are implemented.

[0109] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0110] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0111] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0112] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0113] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An orthogonal frequency division multiplexing transmission method based on probability shaping, characterized in that: include: Grouping constellation points in a quadrature amplitude modulation constellation diagram according to transmit power to obtain a symbol pattern; Constructing a mapping relationship between index bits and modulation strategies according to the set mapping probability to obtain a mode allocation table; The modulation strategy is a way of allocating symbol patterns; Divide the input original bits into an index bit sequence and a data bit sequence, query a preset mode allocation table according to the index bit sequence to obtain a modulation strategy, and perform constellation mapping on the data bits according to the modulation strategy to generate constellation points; Mapping the constellation points onto subcarriers to generate orthogonal frequency division multiplexing symbol blocks; performing inverse fast Fourier transform on the orthogonal frequency division multiplexing 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 the transmission signal is sent from the transmitter to the receiver through the optical fiber channel; In response to receiving the transmission signal, the transmission signal is restored to obtain the original bits.

2. The orthogonal frequency division multiplexing transmission method according to claim 1, wherein: The constellation points in the quadrature amplitude modulation constellation diagram are grouped according to the transmit power to obtain a symbol pattern, specifically including: Calculate the transmit power of each constellation point in the quadrature amplitude modulation constellation diagram. The expression formula is: ； In the formula, P is the transmit power of the constellation point, is the in-phase component of the constellation point, are the orthogonal components of the constellation points; The constellation points in the orthogonal amplitude modulation constellation diagram are sorted according to the transmission power, and the sorted constellation points are divided to obtain symbol patterns, and each symbol pattern contains the same number of constellation points.

3. The orthogonal frequency division multiplexing transmission method according to claim 2, characterized in that: The mapping relationship between the index bit and the modulation strategy is constructed according to the set mapping probability to obtain a mode allocation table, specifically including: Determine the number of modulation strategies based on the number of index bits , by the number of symbol mode mappings within the modulation strategy and the number of modulation strategies Calculate the total number of symbol patterns allocated in the pattern allocation table; Dividing the total allocation quantity according to the set mapping probability of the symbol mode to obtain the allocation quantity of each symbol mode, and obtaining a mode allocation set of the symbol mode; Combine the symbol patterns in the pattern allocation set to generate A modulation strategy is configured, and a mapping relationship is set between the modulation strategy and the index bit to obtain the mode allocation table.

4. The orthogonal frequency division multiplexing transmission method according to claim 1, wherein: Performing an inverse fast Fourier transform on the orthogonal frequency division multiplexing symbol block to obtain 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 OFDM symbol block, and n is the discrete time index of the time domain signal; is an orthogonal frequency division multiplexing symbol block; is pi.

5. The orthogonal frequency division multiplexing transmission method according to claim 1, wherein: Recovering the transmitted signal to obtain the original bits includes: The received transmission 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 converted into a digital form and the cyclic prefix is ​​removed to obtain a time domain signal sequence; Convert the time domain signal sequence into an orthogonal frequency division multiplexing symbol block by fast Fourier transform, and extract the received symbol from the orthogonal frequency division multiplexing symbol block; Calculating the Euclidean distance between the received symbol and the constellation point in the orthogonal amplitude modulation constellation diagram, and determining the symbol mode corresponding to the received symbol based on the minimum Euclidean distance; querying a preset mode allocation table according to the allocation method of the symbol mode to obtain an index bit sequence; Querying a preset mode allocation table according to the index bit sequence to obtain a modulation strategy, and performing constellation demapping on the received symbols according to the modulation strategy to generate a data bit sequence; The index bit sequence and the data bit sequence are concatenated to obtain the original bits.

6. The orthogonal frequency division multiplexing transmission method according to claim 5, characterized in that: The time domain signal sequence is converted into an orthogonal frequency division multiplexing symbol block through fast Fourier transform. The specific process 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 OFDM symbol block, and n is the discrete time index of the time domain signal; is an orthogonal frequency division multiplexing symbol block; is pi.

7. The orthogonal frequency division multiplexing transmission method according to claim 5, characterized in that: Perform constellation demapping on the received symbols according to the modulation strategy to generate a data bit sequence, specifically including: The modulation strategy determines the symbol mode to which the received symbol belongs, calculates the Euclidean distance between the received symbol and the constellation point in the symbol mode to which it belongs, selects the constellation point to which the received symbol is mapped based on the Euclidean distance, and generates a data bit sequence through constellation demapping.

8. An orthogonal frequency division multiplexing transmission system based on probability shaping, characterized in that: include: A mode division module is used to group constellation points in the orthogonal amplitude modulation constellation diagram according to the transmission power to obtain a symbol mode; A mapping relationship between index bits and modulation strategies is constructed according to the set mapping probability to obtain a mode allocation table; the modulation strategy is an allocation method of symbol modes; The constellation mapping module divides the input raw bits into an index bit sequence and a data bit sequence, queries a preset mode allocation table according to the index bit sequence to obtain a modulation strategy, and performs constellation mapping on the data bits according to the modulation strategy to generate constellation points; a signal modulation module that maps the constellation points onto subcarriers to generate orthogonal frequency division multiplexing symbol blocks; performs an inverse fast Fourier transform on the orthogonal frequency division multiplexing symbol blocks to obtain a time domain signal sequence; adds a cyclic prefix to the time domain signal sequence and then generates a transmission signal through digital-to-analog conversion; and transmits the transmission signal from a transmitting end to a receiving end via an optical fiber channel; The signal receiving module recovers the transmission signal to obtain the original bits in response to receiving the transmission signal.

9. An electronic terminal comprising a processor and a storage medium; the storage medium is used to store instructions; characterized in that: The processor is configured to operate according to the instructions to execute the steps of the orthogonal frequency division multiplexing transmission method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the orthogonal frequency division multiplexing transmission method according to any one of claims 1 to 7 are implemented.

Images