A method and system for joint compensation of phase noise and chromatic dispersion based on dual pilot assisted digital subcarrier multiplexing signal

Abstract

The application provides a phase noise and dispersion joint compensation method based on a double pilot aided digital subcarrier multiplexing signal, and relates to the technical field of optical fiber communication. First, a guard interval is set on a digital subcarrier multiplexing signal emitted by a transmitting end, and two pilot signals with set amplitudes and phases are inserted in the guard interval. Then, the amplitudes of the pilot signals are extracted to estimate the dispersion amount of the digital subcarrier multiplexing signal in optical fiber communication system transmission; according to the phases of the two pilot signals, the combination of the phase noise of the transmitting end and the receiving end is obtained at the receiving end, the phase noise is processed, and the phase noise of the transmitting end and the phase noise of the receiving end are separated. Then, the phase noise of the transmitting end is reconstructed to obtain the reconstructed phase noise of the transmitting end; the phase noise of the receiving end is reconstructed to obtain the reconstructed phase noise of the receiving end. Finally, according to the reconstructed phase noise of the transmitting end, the reconstructed phase noise of the receiving end and the dispersion amount, the phase noise of the receiving end, the dispersion and the phase noise of the transmitting end are compensated. The application estimates the phase noise and dispersion generated in the transmission process of the digital subcarrier multiplexing signal by using the phases and amplitudes of the pilot signals, improves the transmission performance of the digital subcarrier multiplexing signal and optimizes the performance of the optical fiber communication system.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of optical fiber communication, and more particularly to a phase noise and dispersion joint compensation method and system based on double pilot assisted digital subcarrier multiplexing signals. BACKGROUND

[0002] As the core hub of global information exchange, data centers carry the functions of storing, processing and distributing massive amounts of data. With the rapid development of cloud computing and big data technology, data centers have an increasing demand for high-speed and high-capacity optical interconnection technology. Optical fiber communication systems, as the main means of connecting within and between data centers, are closely related to the evolution of data centers. Optical fiber nonlinearity, as a decisive factor limiting the transmission capacity of optical fiber communication systems, remains a challenge. In order to suppress optical fiber nonlinearity in optical communication systems, digital subcarrier multiplexing technology is widely used. Compared with traditional single-carrier systems, digital subcarrier multiplexing technology provides higher nonlinearity tolerance, which enables optical communication systems to achieve higher data transmission rates while maintaining signal integrity.

[0003] However, during optical fiber transmission, the signal will be affected by dispersion, and the receiving end needs to adopt dispersion compensation technology to eliminate the damage introduced by dispersion. In the process of dispersion compensation, the interaction of laser phase noise and dispersion will produce equalization-enhanced phase noise, which will cause the signal-to-noise ratio to decrease, thereby affecting the overall performance of the transmission system. The prior art eliminates the equalization-enhanced phase noise using two pilots, but only uses two pilot phases, which has low pilot utilization and cannot accurately estimate the phase noise and dispersion generated during the transmission of digital subcarrier multiplexing signals, resulting in reduced performance of digital subcarrier multiplexing signal transmission and affecting the performance of optical fiber communication systems. SUMMARY

[0004] In order to solve the problem of low pilot utilization and inaccurate estimation of phase noise and dispersion generated during the transmission of digital subcarrier multiplexing signals, which reduces the performance of digital subcarrier multiplexing signal transmission, the present application provides a phase noise and dispersion joint compensation method based on double pilot assisted digital subcarrier multiplexing signals, which improves the performance of digital subcarrier multiplexing signal transmission.

[0005] In order to achieve the above technical effects, the technical solutions of the present application are as follows:

[0006] In a first aspect, the present application provides a phase noise and dispersion joint compensation method based on double pilot assisted digital subcarrier multiplexing signals, which is applied to an optical fiber communication system, the optical fiber communication system includes a transmitting end and a receiving end, and a digital subcarrier multiplexing signal is used as an optical fiber transmission signal of the optical fiber communication system; the method comprises the following steps:

[0007] S1: setting a guard interval on a digital subcarrier multiplexing signal emitted by a transmitting end, and inserting two pilot signals with set amplitudes and phases in the guard interval;

[0008] S2: extracting the amplitudes of the pilot signals, and estimating the dispersion amount of the digital subcarrier multiplexing signal in optical fiber communication system transmission;

[0009] S3: obtaining the combination of the phase noise of the transmitting end and the receiving end at the receiving end according to the phases of the two pilot signals, and performing signal processing on the phase noise to separate the phase noise of the transmitting end and the phase noise of the receiving end;

[0010] S4: reconstructing the phase noise of the transmitting end to obtain the reconstructed phase noise of the transmitting end, and reconstructing the phase noise of the receiving end to obtain the reconstructed phase noise of the receiving end;

[0011] S5: compensating for the phase noise of the receiving end, the dispersion, and the phase noise of the transmitting end according to the reconstructed phase noise of the transmitting end, the reconstructed phase noise of the receiving end, and the dispersion amount.

[0012] Further, the specific steps of step S1 are:

[0013] symmetrically setting a guard interval on the X polarization and the Y polarization of the digital subcarrier multiplexing signal, and inserting a pilot signal with a set amplitude and phase at the center position of each guard interval; the amplitude of the pilot signal carries the information of the modulation code type; the size of the guard interval is a set value.

[0014] Further, the method further comprises: the receiving end identifying the modulation code type of the digital subcarrier multiplexing signal emitted by the transmitting end according to the amplitude of the pilot signal;

[0015] The process of identifying the modulation code type of the digital subcarrier multiplexing signal emitted by the transmitting end according to the amplitude of the pilot signal is:

[0016] First, the amplitude of the pilot signal is extracted, and the expression is:

[0017] A = abs(S tone )

[0018] In the formula, A represents the amplitude of the pilot signal, and S tone represents the pilot signal extracted at the receiving end after digital signal processing;

[0019] Then, the amplitude of the pilot signal is decision demodulated to identify the modulation code type of the digital subcarrier multiplexing signal emitted by the transmitting end.

[0020] According to the above technical means, different modulation code types represent different digital subcarrier multiplex signal coding and transmission modes, and identifying the modulation code type helps to ensure accurate reception and demodulation of the digital subcarrier multiplex signal. By identifying the modulation code type, the receiving end processes the received digital subcarrier multiplex signal according to the modulation code type, thereby improving the efficiency and accuracy of digital subcarrier multiplex signal processing.

[0021] Further, the estimation process of the dispersion amount satisfies:

[0022] First, cross-correlation operation is performed on the amplitude of the extracted pilot signal, and the relative time delay caused by dispersion after the pilot signal is transmitted through the optical fiber is calculated according to the result of the cross-correlation operation; the process satisfies:

[0023] R(m) = E[|A left (k,z)| 2 ·|A right (k-m,z)| 2 ]

[0024] Δτ = m max T s

[0025] In the formula, A left , A right represent the amplitude of the inserted pilot signal, R(m) represents the cross-correlation value, k represents the kth sampling point, z represents the signal transmission distance, T s represents the sampling period, Δτ represents the relative time delay caused by dispersion after the pilot signal is transmitted through the optical fiber, and m represents an integer 0, 1, 2,...;

[0026] Then, the dispersion amount is estimated according to the relative time delay caused by dispersion after the pilot signal is transmitted through the optical fiber, and the expression is:

[0027]

[0028] In the formula, CD represents the dispersion amount, F c represents the optical carrier frequency, f p represents the frequency of the pilot signal, and c represents the speed of light in vacuum.

[0029] Further, the expressions of the phase noise of the transmitting end and the phase noise of the receiving end are respectively:

[0030]

[0031] In the formula, φ represents the combination of the transmitting end and the receiving end phase noise obtained by the receiving end of the first pilot signal, φ TX represents the phase noise caused by the laser linewidth of the transmitting end, and φ RXrepresents the phase noise caused by the laser line width at the receiving end, P represents the insertion position of the pilot signal, L represents the fiber length, β2represents the fiber dispersion parameter, Δω subcarrier represents the subcarrier bandwidth, Δω interval represents the guard interval bandwidth, represents the combination of the transmitting end and receiving end phase noises obtained by the receiving end of the second pilot signal.

[0032] Further, the calculation process of the reconstructed transmitting end phase noise satisfies:

[0033] First, according to the phase noises of the two pilot signals, the change amount of the transmitting end phase noise after the time delay is calculated, and the expression is:

[0034]

[0035] Next, according to the number of samples in the time delay range, the change amount between the transmitting end phase noise samples is calculated, and the expression is:

[0036]

[0037] In the formula, α represents the number of samples in the time delay range, and Ts is the sampling period;

[0038] Finally, the transmitting end phase noise is reconstructed by integral accumulation, and the process satisfies:

[0039]

[0040] In the formula, represents an initial fixed phase value, represents the reconstructed transmitting end phase noise.

[0041] Further, the calculation process of the reconstructed receiving end phase noise is:

[0042] The reconstructed transmitting end phase noise is processed twice with different time delays, and then the phase noises of the corresponding pilot signals are subtracted from the time-delayed transmitting end phase noises, and the average value is calculated to obtain the reconstructed receiving end phase noise, and the calculation expression of the process is:

[0043]

[0044] In the formula, represents the reconstructed receiving end phase noise.

[0045] According to the above technical means, by separating the phase noise of the transmitting end and the receiving end, the influence of the transmitting end and the receiving end on the optical fiber communication system transmission can be accurately analyzed; then the phase noise of the transmitting end and the receiving end is reconstructed, the detailed characteristics of the phase noise of the transmitting end and the receiving end are obtained, which is helpful to realize more accurate phase noise compensation.

[0046] Further, the specific process of step S5 is:

[0047] Before dispersion compensation, the reconstructed receiving end phase noise is applied to compensate the phase noise of the receiving end; then the estimated dispersion amount is applied to compensate the dispersion; the reconstructed transmitting end phase noise is used to compensate the phase noise of the transmitting end, and the process satisfies:

[0048]

[0049] In the formula, S rx (t) represents the signal received by the receiving end, h CDC (t) represents a dispersion compensation function, represents a convolution symbol, CD represents the estimated dispersion amount, and S(t) represents the compensated signal.

[0050] The application also provides a phase noise and dispersion joint compensation system based on a double pilot assisted digital subcarrier multiplexing signal, comprising:

[0051] A pilot signal insertion module is configured to set a guard interval on the digital subcarrier multiplexing signal emitted by the transmitting end, and insert two pilot signals with set amplitudes and phases in the guard interval;

[0052] A dispersion estimation module is configured to extract the amplitudes of the pilot signals and estimate the dispersion amount of the digital subcarrier multiplexing signal in the optical fiber communication system transmission;

[0053] A transmitting and receiving end phase noise acquisition module is configured to acquire the combination of the phase noise of the transmitting end and the receiving end at the receiving end according to the phases of the two pilot signals, and perform signal processing on the phase noise to separate the phase noise of the transmitting end and the phase noise of the receiving end;

[0054] A transmitting and receiving end phase noise reconstruction module is configured to reconstruct the phase noise of the transmitting end to obtain the reconstructed phase noise of the transmitting end, and reconstruct the phase noise of the receiving end to obtain the reconstructed phase noise of the receiving end;

[0055] A compensation module is configured to compensate the phase noise of the receiving end, the dispersion, and the phase noise of the transmitting end according to the reconstructed phase noise of the transmitting end, the reconstructed phase noise of the receiving end, and the dispersion amount.

[0056] The application further provides an electronic device comprising a memory and a processor, wherein the memory stores a computer program, and the processor is configured to execute the steps of the phase noise and dispersion joint compensation method based on the dual-pilot assisted digital subcarrier multiplexing signal through the computer program.

[0057] Compared with the prior art, the method has the following beneficial effects:

[0058] The application provides a phase noise and dispersion joint compensation method based on a dual-pilot assisted digital subcarrier multiplexing signal. First, two pilot signals with set amplitudes and phases are inserted to help the receiving end of an optical fiber communication system accurately synchronize and calibrate the signal of the transmitting end. Then, the phase noise of the transmitting end, the phase noise of the receiving end and the dispersion amount are calculated through the amplitudes and phases to realize more accurate phase noise and dispersion compensation. The application estimates the phase noise and dispersion generated in the transmission process of the digital subcarrier multiplexing signal by using the phases and amplitudes of the pilot signals, improves the performance of the digital subcarrier multiplexing signal transmission, and optimizes the performance of the optical fiber communication system. BRIEF DESCRIPTION OF DRAWINGS

[0059] Figure 1 A flow chart of the phase noise and dispersion joint compensation method based on the dual-pilot assisted digital subcarrier multiplexing signal in the embodiment of the application is shown;

[0060] Figure 2 A structure diagram of the phase noise and dispersion joint compensation system based on the dual-pilot assisted digital subcarrier multiplexing signal proposed in the embodiment of the application is shown;

[0061] Figure 3 A schematic diagram of the electronic device proposed in the embodiment of the application is shown. DETAILED DESCRIPTION

[0062] The accompanying drawings are only used for illustrative description and cannot be understood as a limitation to the patent;

[0063] In order to better illustrate the embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the actual size;

[0064] For those skilled in the art, it is understandable that some well-known content in the drawings may be omitted.

[0065] The technical solutions of the application will be further described below in combination with the drawings and embodiments.

[0066] The positional relationship described in the drawings is only used for illustrative description and cannot be understood as a limitation to the patent;

[0067] Embodiment 1

[0068] The embodiment provides a phase noise and dispersion joint compensation method based on a double pilot assisted digital subcarrier multiplexing signal. Figure 1 As shown in a flowchart of the method, the method is applied to an optical fiber communication system including a transmitting end and a receiving end, and a digital subcarrier multiplexing signal is used as an optical fiber transmission signal of the optical fiber communication system; the method provided by the embodiment includes the following steps.

[0069] S1: setting a guard interval on the digital subcarrier multiplexing signal emitted by the transmitting end, and inserting two pilot signals with set amplitudes and phases in the guard interval;

[0070] S2: extracting the amplitudes of the pilot signals, and estimating a dispersion amount of the digital subcarrier multiplexing signal in optical fiber communication system transmission;

[0071] S3: obtaining a combination of the phase noises of the transmitting end and the receiving end at the receiving end according to the phases of the two pilot signals, and performing signal processing on the phase noises to separate the phase noise of the transmitting end and the phase noise of the receiving end;

[0072] S4: reconstructing the phase noise of the transmitting end to obtain a reconstructed phase noise of the transmitting end, and reconstructing the phase noise of the receiving end to obtain a reconstructed phase noise of the receiving end;

[0073] S5: compensating the phase noise of the receiving end, the dispersion, and the phase noise of the transmitting end according to the reconstructed phase noise of the transmitting end, the reconstructed phase noise of the receiving end, and the dispersion amount.

[0074] In the embodiment, the specific steps of step S1 are as follows: mutually symmetrical guard intervals are respectively set on X polarization and Y polarization of the digital subcarrier multiplexing signal, and a pilot signal with a set amplitude and phase is inserted at the center position of each guard interval; the amplitude of the pilot signal carries modulation code type information; and the size of the guard interval is a set value.

[0075] In the embodiment, two-level amplitude modulation is performed on the pilot signal, the low-level amplitude is 1, and the high-level amplitude is greater than 1. Each frame carries 4-bit modulation code type information. The 4-bit modulation code type information can identify 16 modulation code types.

[0076] In the embodiment, the process of extracting the amplitudes of the pilot signals and estimating the dispersion amount of the digital subcarrier multiplexing signal in optical fiber communication system transmission includes the following steps.

[0077] First, cross-correlation operation is performed on the extracted amplitudes of the pilot signals, and the relative time delay caused by dispersion after the pilot signals are transmitted through the optical fiber is calculated according to the result of the cross-correlation operation; the process satisfies the following formula:

[0078] R(m) = E[|Aleft (k,z)| 2 ·|A right (km,z)| 2 ]

[0079] Δτ=m max T s

[0080] Where A left 、A right represents the amplitude of the inserted pilot signal, R(m) represents the cross-correlation value, k represents the kth sampling point, z represents the signal transmission distance, T s represents the sampling period, Δτ represents the relative delay of the pilot signal due to dispersion after transmission through the optical fiber, and m represents an integer 0, 1, 2, ...;

[0081] Next, the dispersion amount is estimated based on the relative delay caused by dispersion after the pilot signal is transmitted through the optical fiber. The expression is:

[0082]

[0083] Where CD represents the dispersion, F c represents the optical carrier frequency, f p represents the frequency of the pilot signal, and c represents the speed of light in vacuum.

[0084] In this embodiment, based on the phases of the two pilot signals, a combination of the phase noise of the transmitting end and the receiving end is obtained at the receiving end, and signal processing is performed on the phase noise to separate the phase noise of the transmitting end and the phase noise of the receiving end. The expressions of the phase noise of the transmitting end and the phase noise of the receiving end are respectively:

[0085]

[0086] Where, represents the combination of the transmitting and receiving phase noises obtained by the receiving end of the first pilot signal, φ TX represents the phase noise caused by the laser linewidth at the transmitter, φ RX represents the phase noise caused by the laser line width at the receiving end, P represents the insertion position of the pilot signal, L represents the fiber length, β2 represents the fiber dispersion parameter, Δω subcarrier represents the subcarrier bandwidth, Δω interval represents the guard interval bandwidth, It represents the combination of the phase noise of the transmitter and receiver obtained by the second pilot signal receiving end. SC / 2,N SC / 2] indicates the insertion position of the pilot signal. N SC Indicates the total number of subcarriers.

[0087] In this embodiment, dispersion may cause walk-off between pilot signals during optical fiber transmission, resulting in a time delay between subcarriers in the transmitting end phase noise associated with the pilot signal, while the receiving end phase noise associated with the pilot signal remains the same.

[0088] In this embodiment, the optical fiber communication system further includes a transmitter laser and a receiver laser. The transmitter signal light and the receiver local oscillator light originate from different laser light sources, and both exhibit randomly varying laser phase noise. The transmitter phase noise is caused by the transmitter laser linewidth, while the receiver phase noise is caused by the receiver laser linewidth.

[0089] In this embodiment, the phase noise of the transmitter is reconstructed to obtain the reconstructed phase noise of the transmitter. The calculation process of the reconstructed phase noise of the transmitter satisfies:

[0090] First, based on the phase noise of the two pilot signals, the change in the phase noise at the transmitter after the delay is calculated. The expression is:

[0091]

[0092] Next, the variation between the transmitter phase noise samples is calculated based on the number of samples within the delay range. The expression is:

[0093]

[0094] Where α represents the number of samples within the time delay range, and Ts is the sampling period;

[0095] Finally, since the laser phase noise is a Wiener process, the transmitter phase noise is reconstructed by integrating and accumulating, and the process satisfies:

[0096]

[0097] Where, represents an initial fixed phase value, represents the reconstructed transmitter phase noise.

[0098] In this embodiment, the phase noise of the receiving end is reconstructed to obtain the reconstructed phase noise of the receiving end. The calculation process of the reconstructed phase noise of the receiving end is:

[0099] The reconstructed transmitter phase noise is subjected to two different time delays. Then, the delayed transmitter phase noise is subtracted from the corresponding pilot signal phase noise, and the average value is calculated to obtain the reconstructed receiver phase noise. The calculation expression of this process is:

[0100]

[0101] wherein, represents the reconstructed phase noise of the receiving end.

[0102] The specific process of step S5 is: according to the reconstructed phase noise of the transmitting end, the reconstructed phase noise of the receiving end and the estimated dispersion, compensating the phase noise of the receiving end, the dispersion and the phase noise of the transmitting end. Before the dispersion compensation, the reconstructed phase noise of the receiving end is applied to compensate the phase noise of the receiving end; then, the estimated dispersion is applied to compensate the dispersion; the reconstructed phase noise of the transmitting end is applied to compensate the phase noise of the transmitting end, and the process satisfies:

[0103]

[0104] wherein, S rx (t) represents the signal received by the receiving end, h CDC (t) represents the dispersion compensation function, represents the convolution symbol, CD represents the estimated dispersion, and S(t) represents the compensated signal.

[0105] Embodiment 2

[0106] The embodiment provides a phase noise and dispersion joint compensation method based on a double pilot assisted digital subcarrier multiplexing signal, and further comprises the following steps: the receiving end identifies the modulation code type of the digital subcarrier multiplexing signal sent by the transmitting end according to the amplitude of the pilot signal. Different modulation code types represent different digital subcarrier multiplexing signal encoding and transmission modes, and identifying the modulation code type helps to ensure accurate reception and demodulation of the digital subcarrier multiplexing signal. By identifying the modulation code type, the receiving end processes the received digital subcarrier multiplexing signal according to the modulation code type, thereby improving the efficiency and accuracy of digital subcarrier multiplexing signal processing.

[0107] The process of identifying the modulation code type of the digital subcarrier multiplexing signal sent by the transmitting end according to the amplitude of the pilot signal is as follows:

[0108] First, the amplitude of the pilot signal is extracted, and the expression is as follows:

[0109] A = abs(S tone )

[0110] wherein, A represents the amplitude of the pilot signal, S tone represents the pilot signal extracted through digital signal processing at the receiving end;

[0111] Then, the amplitude of the pilot signal is subjected to decision demodulation, and the modulation code type of the digital subcarrier multiplexing signal sent by the transmitting end is identified.

[0112] In the embodiment, the modulation type of the digital subcarrier multiplexing signal transmitted by the transmitting end is identified according to the modulation type coding table.

[0113] In the embodiment, the modulation type coding table is as follows: 0000 represents binary phase shift keying (BPSK), 0001 represents quadrature phase shift keying (QPSK), 0010 represents 8QAM, 0011 represents 6QAM, 0100-0111 represents high-order QAM modulation, 1000-1011 represents time-domain hybrid QAM modulation, and 1100-1111 represents multi-dimensional format.

[0114] Specifically, in the decision demodulation process, the phase and frequency of the signal are calibrated and synchronized according to the information provided by the pilot signal. Then, the signal is decoded by using a demodulation algorithm. Finally, the information after the decision demodulation is compared with the modulation type coding table, and the receiving end can determine the modulation type to which the received signal conforms.

[0115] Embodiment 3

[0116] In the embodiment, a system for jointly compensating phase noise and dispersion based on a double-pilot-aided digital subcarrier multiplexing signal is also provided. As shown in a structural diagram of the system, Figure 2 the system comprises:

[0117] a pilot signal insertion module configured to set a guard interval on the digital subcarrier multiplexing signal transmitted by the transmitting end and insert two pilot signals with set amplitudes and phases in the guard interval;

[0118] a dispersion estimation module configured to extract the amplitudes of the pilot signals and estimate the dispersion amount of the digital subcarrier multiplexing signal in the optical fiber communication system transmission;

[0119] a transmitting-receiving end phase noise acquisition module configured to acquire, at the receiving end, a combination of the phase noise of the transmitting end and the phase noise of the receiving end according to the phases of the two pilot signals, perform signal processing on the phase noise, and separate out the phase noise of the transmitting end and the phase noise of the receiving end;

[0120] a transmitting-receiving end phase noise reconstruction module configured to reconstruct the phase noise of the transmitting end to obtain reconstructed phase noise of the transmitting end, and reconstruct the phase noise of the receiving end to obtain reconstructed phase noise of the receiving end;

[0121] a compensation module configured to compensate, according to the reconstructed phase noise of the transmitting end, the reconstructed phase noise of the receiving end, and the dispersion amount, the phase noise of the receiving end, the dispersion, and the phase noise of the transmitting end.

[0122] Embodiment 4

[0123] As shown in Figure 3As shown, the embodiment of the present application further provides an electronic device, comprising a memory 101, a processor 102 and a computer program stored in the memory 101 and running on the processor 102, wherein the processor 102 implements the steps of the method for jointly compensating phase noise and chromatic dispersion based on a double pilot assisted digital subcarrier multiplexing signal according to the computer program.

[0124] Specifically, in the embodiment, the processor 102 can include a central processing unit (CPU) or a special integrated circuit, or be configured as one or more integrated circuits implementing the embodiment, and the memory 101 can include a mass storage for data or instructions. It can include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disc, a magneto-optical disc, a magnetic tape or a universal serial bus (USB) drive, or a combination of two or more of these. In a suitable case, the memory 101 can include a removable or non-removable (or fixed) medium. In a suitable case, the memory 101 can be inside or outside the integrated gateway disaster recovery device.

[0125] The embodiments are merely examples for clearly illustrating the present application, and are not intended to limit the implementation modes of the present application. Based on the above description, other different forms of changes or variations can also be made by those skilled in the art. It is not necessary or possible to exhaust all the implementation modes. Any modification, equivalent replacement and improvement within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A method for joint compensation of phase noise and chromatic dispersion based on dual pilot-aided digital subcarrier multiplexed signals, the method being applied in an optical fiber communication system including a transmitting end and a receiving end, and a digital subcarrier multiplexed signal being used as an optical fiber transmission signal of the optical fiber communication system, characterized in that, The method comprises the following steps: S1: setting a guard interval on a digital subcarrier multiplexing signal emitted by a transmitting end, and inserting two pilot signals with set amplitudes and phases in the guard interval; S2: extracting the amplitudes of the pilot signals, and estimating the dispersion amount of the digital subcarrier multiplexing signal in optical fiber communication system transmission; S3: obtaining the combination of the phase noise of the transmitting end and the receiving end at the receiving end according to the phases of the two pilot signals, and performing signal processing on the phase noise to separate the phase noise of the transmitting end and the phase noise of the receiving end; S4: reconstructing the phase noise of the transmitting end to obtain the reconstructed phase noise of the transmitting end, and reconstructing the phase noise of the receiving end to obtain the reconstructed phase noise of the receiving end; S5: compensating the phase noise of the receiving end, the dispersion, and the phase noise of the transmitting end according to the reconstructed phase noise of the transmitting end, the reconstructed phase noise of the receiving end, and the dispersion amount.

2. The method according to claim 1, wherein, The specific steps of step S1 are as follows: Symmetrical guard intervals are respectively set on the X polarization and Y polarization of the digital subcarrier multiplexing signal, and a pilot signal with a set amplitude and phase is inserted at the center position of each guard interval; the amplitude of the pilot signal carries the information of the modulation code type; the size of the guard interval is a set value.

3. The method of claim 1, wherein, Further comprising: The receiving end identifies the modulation code type of the digital subcarrier multiplexing signal emitted by the transmitting end according to the amplitude of the pilot signal; The process of identifying the modulation code type of the digital subcarrier multiplexing signal emitted by the transmitting end according to the amplitude of the pilot signal is as follows: First, the amplitude of the pilot signal is extracted, and the expression is as follows: A = abs(S tone ) In the formula, A represents the amplitude of the pilot signal, S tone represents the pilot signal extracted by digital signal processing at the receiving end; Then, the amplitude of the pilot signal is decision demodulated to identify the modulation code type of the digital subcarrier multiplexing signal emitted by the transmitting end.

4. The method of claim 3, wherein the method is characterized by, The estimation process of the dispersion amount satisfies: First, the amplitude of the extracted pilot signal is subjected to cross-correlation operation, and the relative time delay caused by dispersion after the pilot signal is transmitted through the optical fiber is calculated according to the cross-correlation operation result; the process satisfies: R(m) = E[|A left (k, z) 2 · |A right (k - m, z) 2 ] Δτ = m max T s wherein A ｌeft , A right represents the amplitude of the inserted pilot signal, R(m) represents the cross-correlation value, k represents the kth sampling point, z represents the signal transmission distance, T s represents the sampling period, Δτ represents the relative time delay caused by dispersion after the pilot signal is transmitted through the optical fiber, and m represents an integer 0, 1, 2,... Then, the dispersion amount is estimated according to the relative time delay caused by dispersion after the pilot signal is transmitted through the optical fiber, and the expression is as follows: In the formula, CD represents a dispersion amount, f c represents an optical carrier frequency, f p represents a frequency of a pilot signal, and c represents the speed of light in a vacuum.

5. The method of claim 1, wherein, The expressions of the phase noise of the transmitting end and the phase noise of the receiving end are as follows: wherein denotes the combination of the transmitter and receiver phase noise as seen by the first pilot signal receiver, φ TX denotes the transmitter phase noise caused by the laser linewidth, φ RX denotes the receiver phase noise caused by the laser linewidth, P denotes the pilot signal insertion position, L denotes the fiber length, β2denotes the fiber dispersion parameter, Δω subcarrier denotes the subcarrier bandwidth, Δω interval denotes the guard interval bandwidth, denotes the combination of the transmitter and receiver phase noise as seen by the second pilot signal receiver.

6. The method of claim 5, wherein the method further comprises: The calculation process of the reconstructed phase noise of the transmitting end satisfies: First, the change amount of the transmitting end phase noise after time delay is calculated according to the phase noise of the two pilot signals, and the expression is as follows: Then, the change amount between the samples of the transmitting end phase noise is calculated according to the number of samples in the time delay range, and the expression is as follows: In the formula, α represents the number of samples in the time delay range, and Ts is the sampling period; Finally, the transmitting end phase noise is reconstructed by integral accumulation, and the process satisfies: In the formula, represents an initial fixed phase value, represents the reconstructed transmitter phase noise.

7. The method for joint compensation of phase noise and chromatic dispersion of a dual pilot assisted digital subcarrier multiplexed signal according to claim 6, characterized in that, The calculation process of the reconstructed phase noise of the receiving end is as follows: The reconstructed transmitting end phase noise is subjected to two different time delay processes, then the phase noise of the corresponding pilot signal is subtracted from the time delayed transmitting end phase noise, and the average value is calculated to obtain the reconstructed receiving end phase noise, and the calculation expression of the process is as follows: In the formula, represents the reconstructed receiving end phase noise.

8. The method of claim 7, wherein the method further comprises: The specific process of step S5 is as follows: Before dispersion compensation, the reconstructed receiver phase noise is applied to compensate the phase noise of the receiver; then, the estimated dispersion is applied to compensate the dispersion; the reconstructed transmitter phase noise is applied to compensate the phase noise of the transmitter, and the process satisfies: In the formula, S rx (t) represents a signal received by a receiving end, h CDC (t) represents a dispersion compensation function, represents a convolution symbol, CD represents an estimated dispersion amount, and S(t) represents a compensated signal.

9. A system for joint compensation of phase noise and chromatic dispersion based on a dual pilot assisted digital subcarrier multiplexed signal, characterized in that, The method comprises the following steps: A pilot signal insertion module is configured to set a guard interval in a digital subcarrier multiplexing signal transmitted by a transmitter, and insert two pilot signals with set amplitudes and phases into the guard interval; A dispersion estimation module is configured to extract the amplitudes of the pilot signals, and estimate the dispersion of the digital subcarrier multiplexing signal in optical fiber communication system transmission; A transceiver phase noise acquisition module is configured to acquire the combination of the transmitter phase noise and the receiver phase noise at the receiver according to the phases of the two pilot signals, and perform signal processing on the phase noise to separate the transmitter phase noise and the receiver phase noise; A transceiver phase noise reconstruction module is configured to reconstruct the transmitter phase noise to obtain the reconstructed transmitter phase noise, and reconstruct the receiver phase noise to obtain the reconstructed receiver phase noise; A compensation module is configured to compensate the phase noise of the receiver, the dispersion, and the phase noise of the transmitter according to the reconstructed transmitter phase noise, the reconstructed receiver phase noise, and the dispersion.

10. An electronic device comprising a memory and a processor, characterized in that, The memory stores a computer program, and the processor is configured to execute the steps of the method for jointly compensating the phase noise and the dispersion of the digital subcarrier multiplexing signal based on the double pilot assistance according to the computer program.

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