Optical signal sending method, optical signal receiving method, optical fiber channel sending end and receiving end

Abstract

The present invention provides an optical signal transmission method, an optical signal receiving method, an optical fiber channel transmitting end and a receiving end, wherein the method comprises converting the acquired data signal into a frequency domain OFDM signal; generating a time domain baseband OFDM signal according to the frequency domain OFDM signal and a fractional-order discrete Fourier compression transform matrix; performing subcarrier mapping on the time domain baseband OFDM signal using orthogonal frequency division multiplexing technology to generate a subcarrier sequence; performing inverse discrete Fourier transform on the subcarrier sequence to generate a time domain sequence; converting the time domain baseband OFDM signal in the time domain sequence into a power multiplexing signal by non-orthogonal multiple access technology; receiving and detecting the power multiplexing signal, performing noise reduction and crosstalk processing, and then performing a demodulation operation to restore the data signal. The efficient compression of the spectrum is achieved, and the accurate restoration of the compressed spectrum is ensured, which not only improves the transmission capacity of the communication system, but also solves the problems of low spectrum efficiency and signal distortion in the prior art.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical fiber communication, and in particular relates to an optical signal sending method, an optical signal receiving method, an optical fiber channel sending end and a receiving end. Background Art

[0002] Among existing communication technologies, OFDM orthogonal frequency division multiplexing technology has become the mainstream choice for optical fiber transmission. This technology effectively improves the utilization of the spectrum by dividing the wide-frequency optical carrier into multiple orthogonal optical subcarriers. At the same time, OFDM orthogonal frequency division multiplexing technology can also be combined with NOMA non-orthogonal multiple access technology to further improve the efficiency of the communication system and meet the growing needs of users.

[0003] Although OFDM orthogonal frequency division multiplexing technology has many advantages, it is still constrained by the Shannon limit. Within a limited bandwidth, OFDM orthogonal frequency division multiplexing technology can only accommodate a limited number of optical subcarriers, which to a certain extent limits the further improvement of spectrum efficiency. In addition, the core of OFDM orthogonal frequency division multiplexing technology is to maintain the orthogonality between subcarriers to avoid interference between signals. This also means that subcarriers cannot be compressed and superimposed at will, otherwise the orthogonal state will be destroyed, causing serious interference problems and even signal distortion. There is a lack of a technical solution that can both efficiently compress the spectrum and maintain signal orthogonality.

[0004] If a spectrum compression technology can be used to reduce the spectrum that has been OFDMed and reduce the interval between optical subcarriers, more subcarriers can be accommodated in a limited bandwidth, thereby improving spectrum utilization. However, based on the principle of OFDM OFDM, subcarriers cannot be compressed and superimposed at will, otherwise the signals will no longer remain orthogonal, which will cause serious interference and even signal distortion. However, conditional compression of OFDM OFDM subcarrier signals is possible, provided that on the one hand, the signal interference between the compressed subcarriers cannot be too large, and on the other hand, the compressed spectrum can be smoothly and accurately restored after channel transmission. Therefore, the fractional discrete Fourier transform method mFrDFT can be used to conditionally compress OFDM OFDM signals.

[0005] mFrDFT fractional discrete Fourier transform is a more practical spectrum compression technology. Compared with other spectrum compression technologies, this technology has no restrictions on compression factor and modulation format, has higher compatibility and flexibility, and does not produce additional power loss. Therefore, it can be regarded as a better spectrum compression method for compressed OFDM systems. At the same time, the BPSK ID detection algorithm and SIC demodulation technology are used for demodulation at the receiving end, which can smoothly ensure the accurate restoration of the compressed spectrum.

[0006] Up to now, the spectrum compression technology based on fractional discrete Fourier transform has not been well combined with OFDM orthogonal frequency division multiplexing technology and NOMA orthogonal multiple access technology to form a communication system. Summary of the invention

[0007] The technical problem to be solved by the present invention is: how to solve the problems of low spectrum efficiency and signal distortion caused by Shannon limit and orthogonality destruction in the prior art.

[0008] In order to solve the above technical problems, the present invention is implemented by adopting the following technical solutions.

[0009] In a first aspect, the present invention provides a method for sending an optical signal, which is performed by a fiber channel transmitting end, comprising:

[0010] Obtaining a data signal to be sent;

[0011] The acquired data signal is converted into a frequency domain OFDM signal by symbol mapping;

[0012] Generate a time domain baseband OFDM signal according to the frequency domain OFDM signal and the fractional-order discrete Fourier compression transform matrix;

[0013] Perform subcarrier mapping on the time-domain baseband OFDM signal using orthogonal frequency division multiplexing technology to generate a subcarrier sequence;

[0014] Performing an inverse discrete Fourier transform on the subcarrier sequence to generate a time domain sequence;

[0015] The time domain baseband OFDM signal in the time domain sequence is converted into a power multiplexing signal through the NOMA non-orthogonal multiple access technology and input into the optical fiber channel.

[0016] Furthermore, the expression for generating a time domain baseband OFDM signal according to the frequency domain OFDM signal and the fractional-order discrete Fourier compression transform matrix is ​​as follows:

[0017] (1);

[0018] In the formula, represents the time domain baseband OFDM signal, represents the fractional discrete Fourier compression transform matrix, Represents a frequency domain OFDM signal.

[0019] Further, F = 1 Num [ ⋱ e β k 1 l 1 ⋯ e β k 1 ( Num / α − Num + l 2 ) ⋮ ⋱ ⋮ e β l 1 ( Num / α − Num + k 2 ) ⋯ e β ( Num − k 2 )( Num − l 2 ) ⋱ ] (2);

[0020] In the formula, Indicates the number of subcarriers, represents the exponential function, Represents the rotation factors of the fractional discrete Fourier compression transform matrix; , Represents the row index; , Represents the column index, Represents the compression factor.

[0021] Furthermore, the time domain baseband OFDM signal in the time domain sequence is converted into a power multiplexing signal by using the NOMA non-orthogonal multiple access technology, including:

[0022] Use PDM power multiplexing technology to allocate power to multiple time-domain baseband OFDM signals;

[0023] The SC superposition coding technology is used to mix the multi-path time-domain baseband OFDM signals after power allocation to obtain a power multiplexing signal.

[0024] In a second aspect, the present invention further provides a method for receiving an optical signal, which is performed by a receiving end of an optical fiber channel, comprising:

[0025] receiving a power multiplexing signal;

[0026] Performing noise reduction and crosstalk elimination processing on the power multiplexing signal to obtain a processed signal;

[0027] Performing a demodulation operation on the processed signal to restore the data signal;

[0028] Wherein, the power multiplexing signal is obtained by the aforementioned method.

[0029] Furthermore, the power multiplexing signal Perform noise reduction and crosstalk elimination processing to obtain processed signals, including:

[0030] The BPSK ID detection algorithm is used to detect the power multiplexing signal Noise reduction and crosstalk elimination processing are performed, and the expression of the BPSK ID detection algorithm is:

[0031] (3);

[0032] In the formula, Indicates The processed power multiplexed sub-signals, Indicates power multiplexing signal The power multiplexed sub-signals, Represents removal The remaining signals of power multiplexed sub-signals, Represents the power multiplexing sub-signal ICI crosstalk caused; Representative Power multiplexed sub-signals The corresponding additive white Gaussian noise is, Indicates the total number of subcarriers, represents the first Line The elements of the column, where i , q ∈ [ 1 , Num ], p ∈ [ 1 , q ) ∪ ( q , Num ] .

[0033] Furthermore, before the processed signal is demodulated, the processed signal strength is compared with a preset detection threshold distance to make a judgment on the processed signal:

[0034] The power multiplexing signal is divided into multiple power multiplexing sub-signals. If the received power multiplexing sub-signal strength exceeds the preset detection threshold distance, the judgment bit information is 1. If the received power multiplexing sub-signal strength is lower than the preset detection threshold distance, the judgment bit information is 0. All the bit information obtained by the judgment are arranged in order to form a signal to be demodulated.

[0035] Furthermore, the preset calculation formula of the detection threshold distance is expressed as:

[0036] (4);

[0037] In the formula, Indicates the detection threshold distance, represents the modulation format dimension, Indicates the current stage number of the BPSK ID detection algorithm. Indicates the number of iterations of the iterative operation in the current stage of the BPSK ID detection algorithm. Indicates the total number of iterations of the BPSK ID detection algorithm in the current stage.

[0038] In a third aspect, the present invention further provides a fiber channel transmitter, comprising a COFDM modulation module, wherein the COFDM modulation module comprises:

[0039] The power multiplexing sub-signal symbol mapping sub-module is used to obtain a data signal and convert the obtained data signal into a frequency domain OFDM signal through symbol mapping;

[0040] A compression transformation submodule, configured to generate a time domain baseband OFDM signal according to the frequency domain OFDM signal and the fractional-order discrete Fourier compression transformation matrix; and to perform subcarrier mapping on the time domain baseband OFDM signal using an orthogonal frequency division multiplexing technique to generate a subcarrier sequence;

[0041] An inverse transform submodule, used for performing an inverse discrete Fourier transform on the subcarrier sequence to generate a time domain sequence;

[0042] The non-orthogonal multiple access submodule is used to convert the time domain baseband OFDM signal in the time domain sequence into a power multiplexing signal through the NOMA non-orthogonal multiple access technology, and input it into the optical fiber channel.

[0043] In a fourth aspect, the present invention further provides a fiber channel receiving end, comprising a CBID demodulation module, wherein the CBID demodulation module comprises a cascaded BPSK iterative detection submodule and a SIC demodulation submodule;

[0044] The cascaded BPSK iterative detection submodule is used to receive a power multiplexing signal; perform noise reduction and crosstalk elimination processing on the power multiplexing signal to obtain a processed signal;

[0045] The SIC demodulation submodule is used to perform a demodulation operation on the processed signal to restore the data signal;

[0046] Wherein, the power multiplexing signal is obtained by any method described in the first aspect.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] By combining fractional-order discrete Fourier transform mFrDFT, orthogonal frequency division multiplexing (OFDM) and non-orthogonal multiple access (NOMA) technology, the spacing between subcarriers is reduced within a limited frequency band, achieving efficient spectrum compression and significantly improving the spectrum utilization of optical fiber transmission. At the same time, the orthogonality of the signal is guaranteed, solving the problems of low spectrum efficiency and signal distortion caused by the Shannon limit and orthogonality destruction in the existing technology.

[0049] In addition, the BPSK ID detection algorithm and SIC demodulation technology are used for demodulation to ensure the accurate restoration of the compressed spectrum and further improve the transmission capacity of the optical fiber communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a flowchart of a method for sending an optical signal and a method for receiving an optical signal provided by an embodiment of the present invention;

[0051] Figure 2 Schematic diagram of the COFDM modulation module architecture provided by an embodiment of the present invention;

[0052] Figure 3 It is a waveform diagram of a conventional frequency division multiplexing technology provided by an embodiment of the present invention;

[0053] Figure 4 It is a waveform diagram of the orthogonal frequency division multiplexing technology provided by an embodiment of the present invention;

[0054] Figure 5 It is a principle diagram of an orthogonal frequency division multiplexing OFDM orthogonal frequency division multiplexing technology provided by an embodiment of the present invention;

[0055] Figure 6 It is a spectrum effect comparison diagram of the orthogonal frequency division multiplexing (OFDM) orthogonal frequency division multiplexing technology provided by an embodiment of the present invention and the orthogonal frequency division multiplexing (OFDM) orthogonal frequency division multiplexing technology based on fractional-order Fourier transform spectrum compression;

[0056] Figure 7 It is a schematic diagram of the power reuse process of the NOMA non-orthogonal multiple access technology provided by an embodiment of the present invention;

[0057] Figure 8 It is a schematic diagram of the structure of the cascaded BPSK iterative detection submodule provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0058] like Figure 1 As shown, the present invention provides an optical signal sending method and an optical signal receiving method at the optical fiber channel sending end and the optical fiber channel receiving end respectively, so as to realize the high-efficiency transmission of the optical carrier signal in the optical fiber communication system.

[0059] like Figure 2 As shown, the COFDM modulation module provided in the embodiment of the present invention combines the mFrDFT fractional-order discrete Fourier transform compression technology, the NOMA non-orthogonal multiple access technology and the OFDM orthogonal frequency division multiplexing technology for high-spectral-efficiency optical transmission.

[0060] Example 1

[0061] This embodiment introduces a method for sending an optical signal, which is executed by a fiber channel sending end and includes:

[0062] (1) Obtain the data signal to be sent and convert it into a serial binary bit stream;

[0063] (2) Convert a serial binary bit stream into a parallel bit sequence;

[0064] (3) Convert the parallel bit sequence into a frequency domain OFDM signal through symbol mapping;

[0065] (4) Generate a time domain baseband OFDM signal according to the frequency domain OFDM signal and the fractional-order discrete Fourier compression transform matrix. The time domain baseband OFDM signal is expressed as:

[0066] (1);

[0067] In the formula, represents the time domain baseband OFDM signal, represents the fractional discrete Fourier compression transform matrix, Represents a frequency domain OFDM signal.

[0068] The fractional-order discrete Fourier compression transform matrix is ​​expressed as:

[0069] F = 1 Num [ ⋱ e β k 1 l 1 ⋯ e β k 1 ( Num / α − Num + l 2 ) ⋮ ⋱ ⋮ e β l 1 ( Num / α − Num + k 2 ) ⋯ e β ( Num − k 2 )( Num − l 2 ) ⋱ ] (2);

[0070] In the formula, Indicates the number of subcarriers, represents the exponential function, Represents the rotation factors of the fractional discrete Fourier compression transform matrix; , Represents the row index; , Represents the column index, Represents the compression factor.

[0071] The fractional-order discrete Fourier compression transform matrix is ​​divided into four sub-matrices. Line and To ensure the symmetry of the matrix, the first Row and The columns are set to zero frequency region.

[0072] Compared with the traditional inverse discrete Fourier transform, the fractional discrete Fourier transform matrix does not require the number of subcarriers and the compression factor to be integers, which increases the flexibility and compatibility of the system and does not damage the system's tolerance for narrowband filtering. The spectrum effect after the fractional discrete Fourier transform matrix transformation is as follows: Figure 6 As shown in FIG. 1 , the bandwidth occupied by the same number of subcarriers after fractional discrete Fourier transform is smaller than that occupied by traditional OFDM modulation technology, and the extra bandwidth space can accommodate more subcarriers to transmit more data.

[0073] like Figure 5 As shown, orthogonal frequency division multiplexing technology is used to perform subcarrier mapping on the time domain baseband OFDM signal to generate a subcarrier sequence ;

[0074] (5) Subcarrier sequence Then perform inverse discrete Fourier transform to generate the sequence ;

[0075] (6) Sequence Add a cyclic prefix to each time domain baseband OFDM signal in;

[0076] (7) Figure 7As shown in the figure, the time domain baseband OFDM signal is converted into a power multiplexing signal through the NOMA non-orthogonal multiple access technology. The specific steps are:

[0077] Use PDM power multiplexing technology to convert two time-domain baseband OFDM signals into parallel and serial signals and then allocate different powers;

[0078] Then, the SC superposition coding technology is used to mix the two signals after the power distribution to obtain a power multiplexing signal;

[0079] (8) The power multiplexed signal is input into the optical fiber channel as a transmission signal.

[0080] Example 2

[0081] This embodiment also introduces a method for receiving an optical signal, which is executed by a receiving end of an optical fiber channel, and includes:

[0082] (1) Receive power multiplexing signal;

[0083] (2) performing noise reduction and crosstalk elimination processing on the power multiplexing signal to obtain a processed signal;

[0084] (3) Demodulating the processed signal to restore the data signal; wherein the power multiplexing signal is obtained by the method described in Example 1.

[0085] The power multiplexing signal is subjected to noise reduction and crosstalk elimination processing using a BPSK ID detection algorithm, and the expression of the BPSK ID detection algorithm is:

[0086] (3);

[0087] In the formula, Indicates The processed power multiplexed sub-signals, Indicates power multiplexing signal The power multiplexed sub-signals, Represents removal The remaining signals of power multiplexed sub-signals, Represents the power multiplexing sub-signal ICI crosstalk caused; Representative Power multiplexed sub-signals The corresponding additive white Gaussian noise is, Indicates the total number of subcarriers, represents the first Line The elements of the column, where i , q ∈ [ 1 , Num ], p ∈ [ 1 , q ) ∪ ( q , Num ] The process of using the BPSK ID detection algorithm to perform noise reduction and crosstalk elimination on the power multiplexing signal is as follows: Figure 8 shown.

[0088] Before performing a demodulation operation on the processed signal, the processed signal strength is compared with a preset detection threshold distance, and a judgment is made on the processed signal:

[0089] The power multiplexing signal is divided into multiple power multiplexing sub-signals. If the received power multiplexing sub-signal strength exceeds the preset detection threshold distance, the judgment bit information is 1. If the received power multiplexing sub-signal strength is lower than the preset detection threshold distance, the judgment bit information is 0. All the bit information obtained by the judgment is arranged in order to form a signal to be demodulated. .

[0090] In the above process, the determination of the bit information can correct the signal to be demodulated, thereby improving the overall detection accuracy.

[0091] Due to the different preset detection threshold distance values, the BPSK ID detection algorithm performs ICI distortion compensation once after receiving the power multiplexing signal at each stage of noise reduction and crosstalk elimination processing on the power multiplexing signal. Therefore, the ICI interference faced in the next stage will always be less than before, so the detection threshold is also reduced, thereby improving the detection accuracy.

[0092] The preset calculation formula of the detection threshold distance is expressed as:

[0093] (4);

[0094] In the formula, Indicates the detection threshold distance, represents the modulation format dimension, Indicates the current stage number of the BPSK ID detection algorithm. Indicates the number of iterations of the iterative operation in the current stage of the BPSK ID detection algorithm. Indicates the total number of iterations of the BPSK ID detection algorithm in the current stage.

[0095] Signal to be demodulated It is expressed as:

[0096] ;

[0097] In the formula, Indicates the first bit information of the power multiplexing signal obtained by judgment, Indicates the second bit information of the power multiplexing signal obtained by judgment, Indicates the first power multiplexing signal bits of information.

[0098] The final data signal The SIC demodulation eliminates the interference of the decoded signals on other signals one by one, and restores the data signal acquired by the transmitting end of the optical fiber channel.

[0099] Example 3

[0100] The present invention also provides a fiber channel transmitter, comprising a COFDM modulation module,

[0101] The COFDM modulation module includes the following submodules:

[0102] The symbol mapping submodule is used to obtain a data signal; the obtained data signal is used to generate a frequency domain OFDM signal through symbol mapping;

[0103] A compression transformation submodule, used for inputting the frequency domain OFDM signal into a fractional-order discrete Fourier compression transformation matrix to convert it into a time domain baseband OFDM signal, and for performing subcarrier mapping on the time domain baseband OFDM signal using an orthogonal frequency division multiplexing technique to generate a subcarrier sequence;

[0104] An inverse transform submodule, used for performing an inverse discrete Fourier transform on the subcarrier sequence to generate a time domain sequence;

[0105] The non-orthogonal multiple access submodule is used to convert the time domain baseband OFDM signal in the time domain sequence into a power multiplexing signal through the NOMA non-orthogonal multiple access technology, and input it into the optical fiber channel.

[0106] Example 4

[0107] The present invention also provides a fiber channel receiving end, comprising:

[0108] A CBID demodulation module, including a cascaded BPSK iterative detection submodule and a SIC demodulation submodule;

[0109] The cascaded BPSK iterative detection submodule is used to receive and detect the power multiplexing signal, reduce the influence of noise and crosstalk on the power multiplexing signal, and obtain the signal after the noise and crosstalk are reduced.

[0110] The SIC demodulation submodule performs a demodulation operation on the signal after noise and crosstalk are reduced to restore the data signal.

[0111] Example 5

[0112] The present invention also provides a computer-readable storage medium on which a computer program / instruction is stored. When the computer program / instruction is executed by a processor, the steps of the method described in Example 1 or 2 are implemented.

[0113] In summary, according to the above embodiments, Figure 3 , Figure 4 as well as Figure 6 It can be seen that by combining fractional-order discrete Fourier transform mFrDFT, orthogonal frequency division multiplexing OFDM orthogonal frequency division multiplexing technology and non-orthogonal multiple access NOMA technology, the spacing between subcarriers is reduced within a limited frequency band, and efficient spectrum compression is achieved. The spectrum utilization of optical fiber transmission is significantly improved, while the orthogonality of the signal is guaranteed, solving the problems of low spectrum efficiency and signal distortion caused by Shannon limit and orthogonality destruction in the existing technology.

[0114] In addition, the BPSK ID detection algorithm and SIC demodulation technology are used for demodulation to ensure the accurate restoration of the compressed spectrum and further improve the transmission capacity of the optical fiber communication system.

[0115] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented 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.

[0116] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of the present invention.

Claims

1. A method for sending an optical signal, characterized in that: Performed by the Fibre Channel transmitter, including: Obtaining a data signal to be sent; The acquired data signal is converted into a frequency domain OFDM signal by symbol mapping; Generate a time domain baseband OFDM signal according to the frequency domain OFDM signal and the fractional-order discrete Fourier compression transform matrix; Perform subcarrier mapping on the time-domain baseband OFDM signal using orthogonal frequency division multiplexing technology to generate a subcarrier sequence; Performing an inverse discrete Fourier transform on the subcarrier sequence to generate a time domain sequence; The time domain baseband OFDM signal in the time domain sequence is converted into a power multiplexing signal through the NOMA non-orthogonal multiple access technology and input into the optical fiber channel.

2. The optical signal sending method according to claim 1, characterized in that: The expression for generating a time domain baseband OFDM signal according to the frequency domain OFDM signal and the fractional-order discrete Fourier compression transform matrix is ​​as follows: （1）； In the formula, represents the time domain baseband OFDM signal, represents the fractional discrete Fourier compression transform matrix, Represents a frequency domain OFDM signal.

3. The optical signal transmission method according to claim 1 or 2, characterized in that: The expression of the fractional-order discrete Fourier compression transform matrix is ​​as follows: （2）； In the formula, Indicates the number of subcarriers, represents the exponential function, Represents the rotation factors of the fractional discrete Fourier compression transform matrix; , Represents the row index; , Represents the column index, Represents the compression factor.

4. The optical signal sending method according to claim 1, characterized in that: The time domain baseband OFDM signal in the time domain sequence is converted into a power multiplexing signal by using the NOMA non-orthogonal multiple access technology, including: Use PDM power multiplexing technology to allocate power to multiple time-domain baseband OFDM signals; The SC superposition coding technology is used to mix the multi-path time-domain baseband OFDM signals after power allocation to obtain a power multiplexing signal.

5. A method for receiving an optical signal, characterized in that: Performed by the Fibre Channel receiver, including: receiving a power multiplexing signal; Performing noise reduction and crosstalk elimination processing on the power multiplexing signal to obtain a processed signal; Performing a demodulation operation on the processed signal to restore the data signal; Wherein, the power multiplexing signal is obtained by the method described in any one of claims 1 to 4.

6. The optical signal receiving method according to claim 5, characterized in that: Power multiplexing signal Perform noise reduction and crosstalk elimination processing to obtain processed signals, including: The BPSK ID detection algorithm is used to detect the power multiplexing signal Noise reduction and crosstalk elimination processing are performed, and the expression of the BPSK ID detection algorithm is: （3）； In the formula, Indicates The processed power multiplexed sub-signals, Indicates power multiplexing signal The power multiplexed sub-signals, Represents removal The remaining signals of power multiplexed sub-signals, Represents the power multiplexing sub-signal ICI crosstalk caused; Representative Power multiplexed sub-signals The corresponding additive white Gaussian noise is, Indicates the total number of subcarriers, represents the first Line The elements of the column, where .

7. The optical signal receiving method according to claim 6, characterized in that: Before performing a demodulation operation on the processed signal, the processed signal strength is compared with a preset detection threshold distance, and a judgment is made on the processed signal: The power multiplexing signal is divided into multiple power multiplexing sub-signals. If the received power multiplexing sub-signal strength exceeds the preset detection threshold distance, the judgment bit information is 1. If the received power multiplexing sub-signal strength is lower than the preset detection threshold distance, the judgment bit information is 0. All the bit information obtained by the judgment are arranged in order to form a signal to be demodulated.

8. The optical signal receiving method according to claim 7, characterized in that: The preset calculation formula of the detection threshold distance is expressed as: （4）； In the formula, Indicates the detection threshold distance, represents the modulation format dimension, Indicates the current stage number of the BPSK ID detection algorithm. Indicates the number of iterations of the iterative operation in the current stage of the BPSK ID detection algorithm. Indicates the total number of iterations of the BPSK ID detection algorithm in the current stage.

9. A fiber channel transmitter, characterized in that: It includes a COFDM modulation module, and the COFDM modulation module includes: A symbol mapping submodule, used to acquire a data signal, and convert the acquired data signal into a frequency domain OFDM signal through symbol mapping; A compression transformation submodule, configured to generate a time domain baseband OFDM signal according to the frequency domain OFDM signal and the fractional-order discrete Fourier compression transformation matrix; and to perform subcarrier mapping on the time domain baseband OFDM signal using an orthogonal frequency division multiplexing technique to generate a subcarrier sequence; An inverse transform submodule, used for performing an inverse discrete Fourier transform on the subcarrier sequence to generate a time domain sequence; The non-orthogonal multiple access submodule is used to convert the time domain baseband OFDM signal in the time domain sequence into a power multiplexing signal through the NOMA non-orthogonal multiple access technology, and input it into the optical fiber channel.

10. A fiber channel receiving end, characterized in that: It includes a CBID demodulation module, and the CBID demodulation module includes a cascaded BPSK iterative detection submodule and a SIC demodulation submodule; The cascaded BPSK iterative detection submodule is used to receive a power multiplexing signal; perform noise reduction and crosstalk elimination processing on the power multiplexing signal to obtain a processed signal; The SIC demodulation submodule is used to perform a demodulation operation on the processed signal to restore the data signal; Wherein, the power multiplexing signal is obtained by the method described in any one of claims 1 to 4.

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