CN115567162A - Probability constellation shaping method and system, and optical communication method and system - Google Patents
Probability constellation shaping method and system, and optical communication method and system Download PDFInfo
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Abstract
The invention discloses a probability constellation shaping method and system, an optical communication method and system, the invention selects mapping symbols by using a table look-up mode without the high-precision arithmetic process of the traditional CCDM, reduces the coding and decoding complexity of a receiving end and a transmitting end, improves the cost benefit, inhibits the error propagation and accumulation conditions when a receiving end decodes by combining Polar codes with strong error correction performance, ensures the reliability of a transmission system, and is suitable for cost-sensitive scenes such as a short-distance optical access system.
Description
Technical Field
The invention relates to a probability constellation shaping method and system and an optical communication method and system, and belongs to the field of optical fiber communication.
Background
With the increasing demand for data traffic as the network world is changing day by day, the capacity and reliability of optical communication systems are challenging. The advanced modulation format is helpful for improving the spectrum utilization rate and the transmission rate of an optical communication system, has the advantages of chromatic dispersion robustness and the like, and the modulation format which is widely applied at present comprises the following steps: pulse Amplitude Modulation (PAM), orthogonal Frequency Division Multiplexing (OFDM), discrete multi-frequency modulation (DMT), and carrier amplitude phase modulation (CAP). The CAP modulation format has higher spectral efficiency and flexibility due to its multi-level signal constellation and spectral shaping capability, and is one of the most attractive modulation formats. And the application of a Finite Impulse Response (FIR) filter bank can directly generate orthogonal signals, thereby reducing the complexity and equipment cost of the system to a certain extent.
The Probability Constellation Shaping (PCS) technique is one of the important means for increasing the transmission capacity of an optical communication system and approaching the shannon limit. The probability constellation shaping technology improves the occurrence probability of low-energy symbols and reduces the occurrence probability of high-energy symbols by changing the probability distribution of constellation points, so that the lower average transmitting power is realized at the same information rate, the excellent anti-noise robustness is shown, and the reliability of a transmission system is improved.
The current Constant Component Distribution Matcher (CCDM) is a relatively mature probability shaping technology proposed earlier, and can convert independent bernoulli distribution input bit information into output symbols of desired distribution by using a high-precision arithmetic process, however, the high computational complexity increases the cost of a communication system, and limits the application of the communication system in a short-distance optical access system and other scenarios.
Disclosure of Invention
The invention provides a probability constellation shaping method and system and an optical communication method and system, which solve the problems disclosed in the background technology.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a method of probability constellation shaping, comprising:
carrying out series-parallel conversion on binary data to be transmitted to obtain real binary data and imaginary binary data;
sequentially carrying out distribution matching and Polar coding on the binary data of the real part, and carrying out combined mapping on the result of the distribution matching and the result of the Polar coding to obtain the real part information of the constellation point; wherein, the distribution matching is the distribution matching of the prefix-free codebook;
sequentially carrying out distribution matching and Polar coding on the imaginary binary data, and carrying out combined mapping on a distribution matching result and a Polar coding result to obtain imaginary information of the constellation points;
and combining the real part information and the imaginary part information of the constellation points into a probability distribution map of the constellation points.
Sequentially carrying out distribution matching and Polar coding on the binary data of the real part, and carrying out combined mapping on the result of the distribution matching and the result of the Polar coding to obtain the real part information of the constellation point, wherein the method comprises the following steps:
carrying out distribution matching on the real part binary data, and converting information symbols with uniform probability distribution in the real part binary data into coding symbols with target non-uniform probability distribution;
polar coding is carried out on the coding symbols of the target non-uniform probability distribution to obtain redundant check bit bits;
and mapping the coded symbols of the target non-uniform probability distribution and the redundant check bits in a combined manner to obtain the real part information of the constellation points.
Sequentially carrying out distribution matching and Polar coding on the imaginary binary data, and carrying out combined mapping on a distribution matching result and a Polar coding result to obtain imaginary information of the constellation point, wherein the imaginary information comprises the following steps:
performing distribution matching on the imaginary binary data, and converting information symbols with uniform probability distribution in the imaginary binary data into coding symbols with target non-uniform probability distribution;
polar coding is carried out on the coding symbols of the target non-uniform probability distribution to obtain redundant check bit bits;
and mapping the coded symbols of the target non-uniform probability distribution and the bits of the redundant check bits in a combined manner to obtain imaginary part information of the constellation points.
A probabilistic constellation shaping system, comprising:
the serial-parallel conversion module is used for carrying out serial-parallel conversion on binary data to be transmitted to obtain real binary data and imaginary binary data;
the real part shaping module is used for sequentially carrying out distribution matching and Polar coding on the real part binary data, and carrying out combined mapping on a result of the distribution matching and a result of the Polar coding to obtain real part information of the constellation point; wherein, the distribution matching is the distribution matching of the prefix-free codebook;
the imaginary part shaping module is used for sequentially carrying out distribution matching and Polar coding on the imaginary part binary data, and carrying out combined mapping on a distribution matching result and a Polar coding result to obtain imaginary part information of the constellation point;
and the combination module is used for combining the real part information and the imaginary part information of the constellation points into the probability distribution map of the constellation points.
The real part shaping module comprises:
the real part distribution matcher is used for carrying out distribution matching on real part binary data and converting information symbols with uniform probability distribution in the real part binary data into coding symbols with target non-uniform probability distribution;
the real part Polar encoder is used for carrying out Polar encoding on the encoding symbols of the target non-uniform probability distribution to obtain redundant check bit bits;
and the real part mapping unit is used for mapping the coded symbols of the target non-uniform probability distribution and the redundant check bit combinations to obtain the real part information of the constellation points.
The imaginary part shaping module comprises:
the imaginary part distribution matcher is used for carrying out distribution matching on imaginary part binary data and converting information symbols with uniform probability distribution in the imaginary part binary data into coding symbols with target non-uniform probability distribution;
an imaginary Polar encoder, configured to perform Polar encoding on the encoded symbols of the target non-uniform probability distribution to obtain redundant check bit bits;
and the imaginary part mapping unit is used for mapping the coded symbols of the target non-uniform probability distribution and the redundant check bit combination to obtain the imaginary part information of the constellation points.
An optical communication method, comprising:
obtaining a probability distribution map of constellation points by adopting a probability constellation shaping method;
and carrying out carrier amplitude phase modulation on the probability distribution map, and sending the probability distribution map subjected to the carrier amplitude phase modulation to a receiving end.
The carrier amplitude phase modulation of the probability distribution map comprises:
carrying out a plurality of times of up-sampling on the constellation symbol information in the probability distribution map;
carrying out orthogonal filtering on the constellation symbol information after the multiple times of up-sampling;
and summing the two paths of output of the orthogonal filtering into one path.
An optical communication system comprising:
the probability constellation shaping module is used for obtaining a probability distribution map of constellation points by adopting a probability constellation shaping method;
and the carrier amplitude and phase modulation module is used for carrying out carrier amplitude and phase modulation on the probability distribution map and sending the probability distribution map subjected to the carrier amplitude and phase modulation to a receiving end.
The carrier amplitude phase modulation module comprises:
the up-sampling module is used for carrying out up-sampling on the constellation symbol information in the probability distribution map by a plurality of times;
the orthogonal filter is used for carrying out orthogonal filtering on the constellation symbol information after the multiple times of up-sampling;
and the adder is used for adding the two paths of output of the orthogonal filtering into one path.
The invention achieves the following beneficial effects: the invention selects the mapping symbol by using a table look-up mode without the high-precision arithmetic process of the traditional CCDM, reduces the coding and decoding complexity of a transmitting end and a receiving end, improves the cost benefit, inhibits the error propagation and accumulation conditions when a receiving end decodes by combining Polar codes with strong error correction performance, ensures the reliability of a transmission system, and is suitable for cost-sensitive scenes such as a short-distance optical access system and the like.
Drawings
FIG. 1 is a flow chart of a probabilistic constellation shaping method;
FIG. 2 is a flow chart of Polar encoding;
FIG. 3 is a probability distribution graph of constellation points;
FIG. 4 is a flow chart of carrier amplitude phase modulation;
FIG. 5 (a) is a probability-shaped constellation diagram obtained by the present invention;
FIG. 5 (b) is a standard 16-CAP uniform probability distribution constellation under the same parameters;
fig. 6 (a) is a receiving end symbol error rate curve of three methods under different signal-to-noise ratios (SNRs);
fig. 6 (b) is a receiving end bit error rate curve of three methods under different signal-to-noise ratios (SNRs).
Detailed Description
The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
As shown in fig. 1, a method for shaping a probability constellation includes the following steps:
and 3, combining the real part information and the imaginary part information of the constellation points into a probability distribution map of the constellation points.
The method is implemented at the transmitting end of optical communication, a high-precision arithmetic process of the traditional CCDM is not needed, mapping symbols are selected by utilizing a table look-up mode, the coding and decoding complexity of the transmitting and receiving ends is reduced, the cost benefit is improved, error propagation and accumulation conditions during decoding of the receiving end are inhibited by combining Polar codes with strong error correction performance, the reliability of a transmission system is guaranteed, and the method is suitable for cost-sensitive scenes such as a short-distance optical access system.
In an optical communication system, binary data to be transmitted at a transmitting end is binary bit stream, and a string of binary bit stream needs to be converted in series-parallel, that is, a string of binary bit stream is converted into parallel real part binary data and imaginary part binary data.
The serial-to-parallel conversion is to extract part of the digital codes in the binary bit stream to form real binary data, and the rest part of the digital codes to form imaginary binary data, and the extraction principle is determined according to the actual situation, for example, even-numbered bits are real binary data, and odd-numbered bits are imaginary binary data.
The two columns of binary data respectively obtain the real part information of the constellation point and the imaginary part information of the constellation point in the same way, and the process can be as follows:
1. firstly, binary data are distributed and matched, specifically, the binary data are input into a distribution matcher (PCDM) without a prefix codebook, and the codebook representation of the PCDM is shown in a table 1;
table 1 codebook example for DM
And the code symbols output by the distribution matcher for converting the uniform probability distribution information symbols into the target non-uniform probability distribution, for example, the input information symbol bits B ∈ B: = {0,1}, and the probabilities of B =0 and B =1 are equal to 0.5, and the code symbols output after passing through the distribution matcher are used for representing the unipolar amplitude information a ∈ X: ∈ 1,3, \ 8230, 2M-1}.
Based on PCDM, the amplitude information of target probability distribution can be directly obtained through the design and selection of a codebook, and probability amplitude shaping is completed; the codebook of the PCDM may be freely designed in a huffman coding manner, assuming that the total input bit number of the PCDM is k, the output coding symbol number is n, and the coding rate Rd may be represented as: rd = k/n.
Therefore, the information rate matching can be achieved by utilizing the input and output symbol corresponding relation of the codebook. Taking the codebook of table 1 as an example, the simulation process calculates the encoding rate Rd to be about 0.866. When the input binary sequence to the distribution matcher is long enough, all input bits will have code symbols corresponding to them. As can be seen from the output coded symbols of the codebook, the probability of the occurrence of the symbol "1" is much greater than "3", and the probability amplitude shaping is realized, so the probability of the constellation symbol with low energy in the final constellation point is much greater than that of the constellation symbol with high energy.
2. And carrying out Polar coding on the coding symbols of the target non-uniform probability distribution to obtain redundant check bit bits.
Polar code is a forward error correction code (FEC) based on channel polarization theory proposed by arika, and the channel polarization process includes two stages of channel association and channel splitting, and a good channel with relatively high reliability is obtained through channel polarization and is used for transmitting information, and a poor channel with low reliability is used for transmitting fixed bit information. Recent research on Polar codes has shown that systematically coded Polar codes have superior performance compared to non-systematically coded Polar codes. By a cascade list-Cyclic Redundancy Check (CRC) decoding method, system Polar coding adopting a Serial Cancellation List (SCL) decoder at a receiving end has excellent error correction capability comparable to low density parity check codes (LDPC).
Due to the fact that Polar coding is adopted, as shown in fig. 2, after coded symbols obtained through PCDM are subjected to forward error correction coding, information coded symbols after Polar coding and redundant check bit bits are separated through an interleaver; in the figure, { U In { U } a set of information-encoded symbols representing a non-uniform probability distribution of interest, { U Fn And expressing a redundant check bit set added after Polar coding, wherein the characteristic of non-uniform probability distribution of final coding symbols can be reserved.
Polar coding serving as a forward error correcting code is placed inside PCDM mapping, and the error correcting capability of the Polar coding can effectively inhibit the problems of error propagation and synchronous errors during decoding of a DM decoder, thereby ensuring the transmission reliability of an optical communication system to a certain extent.
3. And mapping the coding symbol of the target non-uniform probability distribution and the bit combination of the redundant check bit to obtain the real part/imaginary part information of the constellation point, namely mapping the coding symbol a ∈ X: = {1,3, \ 8230:, 2M-1} obtained by PCDM and the bit combination of the redundant check bit after Polar coding to the real part or the imaginary part information of the constellation point.
The process of obtaining the real part information of the constellation point can be described as follows: carrying out distribution matching on the real part binary data, and converting information symbols with uniform probability distribution in the real part binary data into coding symbols with target non-uniform probability distribution; polar coding is carried out on the coding symbols of the target non-uniform probability distribution to obtain redundant check bit bits; and mapping the coded symbols of the target non-uniform probability distribution and the redundant check bit combination to obtain the real part information of the constellation point.
The process of obtaining the imaginary information of the constellation points can be described as: performing distribution matching on the imaginary binary data, and converting information symbols with uniform probability distribution in the imaginary binary data into coding symbols with target non-uniform probability distribution; polar coding is carried out on the coding symbols of the target non-uniform probability distribution to obtain redundant check bit bits; and mapping the coded symbols of the target non-uniform probability distribution and the bits of the redundant check bits in a combined manner to obtain imaginary part information of the constellation points.
And finally, combining the real part information and the imaginary part information of the constellation points into a probability distribution diagram of the constellation points, specifically as shown in fig. 3, after probability shaping, the probability of the constellation points with the same radius is approximately the same, and the probability of the constellation points with different radii approximately obeys maxwell boltzmann distribution.
Based on the same technical scheme, the invention also discloses a software system of the method, and a probability constellation shaping system comprises the following steps:
and the serial-parallel conversion module is used for performing serial-parallel conversion on the binary data to be transmitted to obtain real binary data and imaginary binary data.
The real part shaping module is used for sequentially carrying out distribution matching and Polar coding on the real part binary data, and carrying out combined mapping on a result of the distribution matching and a result of the Polar coding to obtain real part information of the constellation point; wherein the distribution matching is prefix-free codebook distribution matching.
The real part shaping module comprises:
the real part distribution matcher is used for carrying out distribution matching on real part binary data and converting information symbols with uniform probability distribution in the real part binary data into coding symbols with target non-uniform probability distribution;
the real part Polar encoder is used for carrying out Polar encoding on the encoding symbols of the target non-uniform probability distribution to obtain redundant check bit bits;
and the real part mapping unit is used for mapping the coded symbols of the target non-uniform probability distribution and the redundant check bit combinations to obtain the real part information of the constellation points.
And the imaginary part shaping module is used for sequentially carrying out distribution matching and Polar coding on the imaginary part binary data, and carrying out combined mapping on a distribution matching result and a Polar coding result to obtain the imaginary part information of the constellation point.
The imaginary part shaping module comprises:
the imaginary part distribution matcher is used for carrying out distribution matching on the imaginary part binary data and converting information symbols with uniform probability distribution in the imaginary part binary data into coding symbols with target non-uniform probability distribution;
an imaginary Polar encoder, configured to perform Polar encoding on the encoded symbols of the target non-uniform probability distribution to obtain redundant check bit bits;
and the imaginary part mapping unit is used for mapping the coded symbols of the target non-uniform probability distribution and the redundant check bit combination to obtain the imaginary part information of the constellation points.
And the combination module is used for combining the real part information and the imaginary part information of the constellation points into the probability distribution map of the constellation points.
Based on the same technical scheme, the invention also discloses an optical communication method, which comprises the following steps:
s1) obtaining a probability distribution map of constellation points by adopting a probability constellation shaping method.
And S2) carrying out Carrier Amplitude Phase (CAP) modulation on the probability distribution map, and sending the probability distribution map subjected to the carrier amplitude phase modulation to a receiving end.
After the probability distribution map of the constellation point is obtained, it is further required to perform carrier amplitude phase modulation, which may specifically be as follows as shown in fig. 4:
31 Several times of up-sampling is carried out on the constellation symbol information in the probability distribution diagram, so that the multiple period expansion of the signal on the frequency spectrum is realized, and the up-sampled symbol information is obtained;
32 Orthogonal filtering is performed on the constellation symbol information after the multiple times of up-sampling;
symbol information is mainly input into two mutually orthogonal FIR filters for orthogonal filtering, and tap coefficients of the filters can be adjusted according to actual conditions;
33 Add the two outputs of the orthogonal filtering into one to complete the CAP modulation.
The above is the flow of the sending end of the optical communication method, the receiving end is the reverse order operation, the original data is restored by adopting the serial cancellation list decoding (SCL) algorithm and the de-distribution matching, and specifically, a Polar decoder and a PCDM decoder are adopted, wherein the Polar decoder is in front of the PCDM decoder, and can effectively correct the error code during transmission, ensure the accuracy of the symbol entering the DM decoder, and ensure the reliability of the transmission system.
A constellation diagram of a receiving end is obtained through simulation, fig. 5 (a) is the probability-shaped constellation diagram obtained by the invention, and fig. 5 (b) is a standard 16-CAP uniform probability distribution constellation diagram under the same parameters. As can be seen from the distribution of the constellation points, the probability of occurrence of the constellation points with low energy (inner part) in fig. 5 (a) is much greater than that of the constellation points with high energy (peripheral part), thereby realizing constellation probability shaping; compared with 18-CAP constellation points with uniform probability distribution, the constellation points obtained by the method are more concentrated and have better effect.
FIG. 6 (a) is a receiving end symbol error rate curve of the invention based on probability constellation shaping without a prefix codebook distribution matcher and standard 16-CAP under different signal-to-noise ratios (SNR), and it can be seen from the figure that the symbol error rate of constellation symbols after shaping without a prefix codebook distribution matcher is superior to that of constellation symbols of standard 16-CAP, and the symbol error rate is improved by about 1dB by probability shaping; since the Polar coding as forward error correction plays a role after receiving constellation symbols, the symbol error rate curves of the two methods of the presence or absence of the forward Polar coding in the graph (a) have no obvious difference; wherein block PCDM w/i Polar denotes the joint Polar coded PCDM scheme (invention), circular PCDM w/o Polar denotes the pure PCDM scheme without joint Polar coding, triangular Normal w/o Polar denotes the standard 16CAP modulation scheme.
FIG. 6 (b) is a plot of the bit error rate for three schemes, where the bit error rate drops to 1E-5 as the SNR is increased according to the present invention; under the condition of no Polar coding, the error propagation is caused by a PCDM decoder due to more error symbols received by the PCDM decoder under the low signal-to-noise ratio, and the finally received error rate is close to 0.5; the bit error rate curve of the standard 16-CAP is reduced along with the increase of the signal-to-noise ratio, and the bit error rate is reduced to be below 1E-3 when the signal-to-noise ratio is larger than 6. Compared with the bit error rate curve of the standard 16-CAP, the invention has very high signal-to-noise ratio gain.
Based on the same technical scheme, the invention also discloses a software system of the optical communication method, and the optical communication system comprises:
and the probability constellation shaping module is used for obtaining the probability distribution map of the constellation points by adopting a probability constellation shaping method.
And the carrier amplitude and phase modulation module is used for carrying out carrier amplitude and phase modulation on the probability distribution map and sending the probability distribution map subjected to the carrier amplitude and phase modulation to a receiving end.
The carrier amplitude phase modulation module comprises:
the up-sampling module is used for carrying out a plurality of times of up-sampling on the constellation symbol information in the probability distribution map;
the orthogonal filter is used for carrying out orthogonal filtering on the constellation symbol information after the multiple times of up-sampling;
and the adder is used for adding the two paths of output of the orthogonal filtering into one path.
Based on the same technical solution, the present invention also discloses a computer-readable storage medium storing one or more programs, the one or more programs including instructions, which when executed by a computing device, cause the computing device to perform a probabilistic constellation shaping method or an optical communication method.
Based on the same technical solution, the present invention also discloses a computing device comprising one or more processors, one or more memories, and one or more programs, wherein the one or more programs are stored in the one or more memories and configured to be executed by the one or more processors, and the one or more programs include instructions for executing the probabilistic constellation shaping method or the optical communication method.
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may 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, and the like) having computer-usable program code embodied therein.
The present invention has been 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 flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may 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, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The present invention is not limited to the above embodiments, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are included in the scope of the claims of the present invention which are filed as the application.
Claims (10)
1. A method for probability constellation shaping, comprising:
carrying out series-parallel conversion on binary data to be transmitted to obtain real binary data and imaginary binary data;
sequentially carrying out distribution matching and Polar coding on the binary data of the real part, and carrying out combined mapping on the result of the distribution matching and the result of the Polar coding to obtain the real part information of the constellation point; wherein, the distribution matching is the distribution matching of the prefix-free codebook;
sequentially carrying out distribution matching and Polar coding on the imaginary binary data, and carrying out combined mapping on a distribution matching result and a Polar coding result to obtain imaginary information of the constellation points;
and combining the real part information and the imaginary part information of the constellation points into a probability distribution map of the constellation points.
2. The method according to claim 1, wherein the step of sequentially performing distribution matching and Polar coding on the real binary data, and performing combined mapping on the result of the distribution matching and the result of the Polar coding to obtain the real information of the constellation point comprises:
carrying out distribution matching on the real binary data, and converting information symbols with uniform probability distribution in the real binary data into coding symbols with target non-uniform probability distribution;
polar coding is carried out on the coding symbols of the target non-uniform probability distribution to obtain redundant check bit bits;
and mapping the coded symbols of the target non-uniform probability distribution and the redundant check bit combination to obtain the real part information of the constellation point.
3. The method of claim 1, wherein the step of sequentially performing distribution matching and Polar coding on the imaginary binary data and mapping the result of the distribution matching and the result of the Polar coding to obtain the imaginary information of the constellation point comprises:
performing distribution matching on the imaginary binary data, and converting information symbols with uniform probability distribution in the imaginary binary data into coding symbols with target non-uniform probability distribution;
polar coding is carried out on the coding symbols of the target non-uniform probability distribution to obtain redundant check bit bits;
and mapping the coded symbols of the target non-uniform probability distribution and the redundant check bit combination to obtain the imaginary part information of the constellation points.
4. A probabilistic constellation shaping system, comprising:
the serial-parallel conversion module is used for carrying out serial-parallel conversion on binary data to be transmitted to obtain real binary data and imaginary binary data;
the real part shaping module is used for sequentially carrying out distribution matching and Polar coding on the real part binary data, and carrying out combined mapping on a result of the distribution matching and a result of the Polar coding to obtain real part information of the constellation point; wherein, the distribution matching is the distribution matching of the prefix-free codebook;
the imaginary part shaping module is used for sequentially carrying out distribution matching and Polar coding on the imaginary part binary data, and carrying out combined mapping on a distribution matching result and a Polar coding result to obtain imaginary part information of the constellation point;
and the combination module is used for combining the real part information and the imaginary part information of the constellation points into the probability distribution map of the constellation points.
5. The system according to claim 4, wherein the real part shaping module comprises:
the real part distribution matcher is used for carrying out distribution matching on real part binary data and converting information symbols with uniform probability distribution in the real part binary data into coding symbols with target non-uniform probability distribution;
the real part Polar encoder is used for carrying out Polar encoding on the encoding symbols of the target non-uniform probability distribution to obtain redundant check bit bits;
and the real part mapping unit is used for mapping the coded symbols of the target non-uniform probability distribution and the redundant check bit combinations to obtain the real part information of the constellation points.
6. The system according to claim 4, wherein the imaginary part shaping module comprises:
the imaginary part distribution matcher is used for carrying out distribution matching on the imaginary part binary data and converting information symbols with uniform probability distribution in the imaginary part binary data into coding symbols with target non-uniform probability distribution;
an imaginary Polar encoder, configured to perform Polar encoding on the encoded symbols of the target non-uniform probability distribution to obtain redundant check bit bits;
and the imaginary part mapping unit is used for mapping the coded symbols of the target non-uniform probability distribution and the redundant check bit combination to obtain imaginary part information of the constellation points.
7. An optical communication method, comprising:
obtaining a probability distribution map of constellation points by adopting the method of any one of claims 1 to 3;
and carrying out carrier amplitude phase modulation on the probability distribution map, and sending the probability distribution map subjected to the carrier amplitude phase modulation to a receiving end.
8. The optical communication method of claim 7, wherein the carrier amplitude phase modulating the probability distribution map comprises:
carrying out a plurality of times of up-sampling on the constellation symbol information in the probability distribution map;
carrying out orthogonal filtering on the constellation symbol information after the multiple times of up-sampling;
and summing the two paths of output of the orthogonal filtering into one path.
9. An optical communication system, comprising:
a probability constellation shaping module, which is used for obtaining a probability distribution map of constellation points by adopting the method of any one of claims 1 to 3;
and the carrier amplitude and phase modulation module is used for carrying out carrier amplitude and phase modulation on the probability distribution map and sending the probability distribution map subjected to the carrier amplitude and phase modulation to a receiving end.
10. The optical communication system of claim 9, wherein the carrier amplitude phase modulation module comprises:
the up-sampling module is used for carrying out up-sampling on the constellation symbol information in the probability distribution map by a plurality of times;
the orthogonal filter is used for carrying out orthogonal filtering on the constellation symbol information after the multiple times of up-sampling;
and the adder is used for adding the two paths of output of the orthogonal filtering into one path.
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