Four-dimensional modulation signal recovery method, device, equipment, medium and product

Abstract

The invention relates to the field of optical fiber communication, in particular to a four-dimensional modulation signal recovery method and device, equipment, a medium and a product, and the method comprises the steps: dynamically obtaining a corresponding filter tap coefficient and phase information needed by phase compensation for each piece of target point information, the filter tap coefficient is updated based on the filter tap coefficient of the previous target point information and the original sending signal sequence, and the phase information corresponding to the target point information is updated based on the phase information of the previous target point information and the original sending signal sequence; low-complexity and robust phase estimation for four-dimensional modulation irregular constellation points is realized; performing nonlinear signal equalization by using an MIMO nonlinear equalizer in combination with target point information and a filter tap coefficient; phase compensation is carried out according to the balanced output signal and the phase information, and phase recovery is carried out while multi-dimensional balancing is carried out, so that the phase noise influence of balancing enhancement is reduced, and the transmission reliability of the four-dimensional modulation signal is improved.

Description

Technical Field

[0001] The present application relates to the field of optical fiber communications, and in particular to a method, device, equipment, medium and product for recovering a four-dimensional modulated signal. Background Art

[0002] In polarization-multiplexed coherent optical communication systems, four-dimensional modulation technology achieves higher spectral efficiency by multiplexing the four dimensions of the X, Y polarization states in the optical field and the in-phase and orthogonal components of each polarization state. However, the crosstalk between the X and Y polarization states and the IQ imbalance effect deteriorate the transmission performance of the four-dimensional modulated signal, and the fiber Kerr effect causes nonlinear distortion of the signal in four dimensions. MIMO nonlinear equalizer is an equalizer used to eliminate inter-symbol interference (ISI) and nonlinear distortion in MIMO (multiple-input multiple-output) systems.

[0003] However, the two-dimensional projected constellation points of many four-dimensional modulation formats are irregular, which results in poor results when traditional carrier phase estimation algorithms for standard QAM / PSK constellations, such as blind phase search, perform phase estimation on four-dimensional modulation constellations.

[0004] Therefore, how to improve the phase estimation of the signal to improve the signal quality has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0005] The purpose of the present application is to provide a method, device, equipment, medium and product for recovering a four-dimensional modulated signal, which can improve the phase estimation of the signal to improve the signal quality.

[0006] In a first aspect, a method for recovering a four-dimensional modulated signal is provided, comprising:

[0007] Acquire an input signal sequence and an original transmission signal sequence, wherein both the input signal sequence and the original transmission signal sequence are normalized four-dimensional modulation signal sequences;

[0008] For each target point information of the input signal sequence, the filter tap coefficient corresponding to the target point information and the phase information required for phase compensation corresponding to the target point information are obtained, wherein the filter tap coefficient corresponding to the target point information is obtained based on the filter tap coefficient corresponding to the previous target point information and the original transmitted signal sequence, and the phase information corresponding to the target point information is obtained based on the phase information corresponding to the previous target point information and the original transmitted signal sequence; nonlinear signal equalization of the MIMO nonlinear equalizer is performed according to the target point information and the filter tap coefficient to obtain an equalized output signal; and phase compensation is performed according to the equalized output signal and the phase information to obtain a recovered signal;

[0009] After the equalization processing of all target point information is completed, the restored signals corresponding to all target point information are obtained.

[0010] In a preferred example, the present application may be further configured as follows: performing nonlinear signal equalization of a MIMO nonlinear equalizer according to the target point information and the filter tap coefficients to obtain an equalized output signal includes:

[0011] Generate a first-order kernel and a second-order kernel of a MIMO nonlinear equalizer corresponding to the target point information according to the target point information;

[0012] Perform signal equalization according to the first-order kernel and the second-order kernel of the MIMO nonlinear equalizer corresponding to the target point information, and the filter tap coefficients to obtain a first equalized output signal;

[0013] The first balanced output signal is combined in the X polarization direction and the Y polarization direction to obtain a second balanced output signal as the balanced output signal.

[0014] In a preferred example, the present application may be further configured as follows: after performing nonlinear signal equalization of the MIMO nonlinear equalizer according to the target point information and the filter tap coefficients to obtain an equalized output signal, the configuration further includes:

[0015] Calculate an error signal corresponding to the target point information according to the equalized output signal corresponding to the target point information and the original target point transmission information corresponding to the target point information in the original transmission signal sequence;

[0016] Perform phase estimation based on the error signal corresponding to the target point information and the phase information corresponding to the target point information, and determine the phase information corresponding to the next target point information;

[0017] The filter tap coefficient corresponding to the next target point information is determined according to the error signal corresponding to the target point information and the filter tap coefficient corresponding to the target point information.

[0018] In a preferred example, the present application can be further configured as follows: the process of determining the information of each target point includes:

[0019] According to the input signal sequence, target point information of the input signal sequence is determined through a sliding window according to a preset sliding distance.

[0020] In a preferred example, the present application may be further configured as follows: when the target point information is the first target information point, the filter tap coefficient corresponding to the target point information is the initial filter tap coefficient, and the phase information corresponding to the target point information is the initial phase information;

[0021] The first-order tap coefficients in the initial filter tap coefficients , , , The middle position of is assigned a value of 1, and the other values ​​are set to 0;

[0022] The initial phase information is determined according to the phase difference between the midpoint information of the original transmitted signal sequence and the corresponding position information of the input signal sequence.

[0023] In a preferred example, the present application may be further configured as follows: after completing the equalization processing of all target point information and obtaining the restored signals corresponding to all target point information, the following further includes:

[0024] Generate a recovery signal sequence according to the recovery signals corresponding to all target point information;

[0025] The restored signal sequence is normalized to obtain a normalized signal sequence.

[0026] In a second aspect, a device for recovering a four-dimensional modulated signal is provided, comprising:

[0027] An acquisition module, used to acquire an input signal sequence and an original transmission signal sequence, wherein both the input signal sequence and the original transmission signal sequence are normalized four-dimensional modulation signal sequences;

[0028] An equalization and phase compensation module is used to obtain, for each target point information of the input signal sequence, the filter tap coefficient corresponding to the target point information and the phase information required for phase compensation corresponding to the target point information, wherein the filter tap coefficient corresponding to the target point information is obtained based on the filter tap coefficient corresponding to the previous target point information and the original transmitted signal sequence, and the phase information corresponding to the target point information is obtained based on the phase information corresponding to the previous target point information and the original transmitted signal sequence; nonlinear signal equalization of the MIMO nonlinear equalizer is performed according to the target point information and the filter tap coefficient to obtain an equalized output signal; and phase compensation is performed according to the equalized output signal and the phase information to obtain a recovered signal;

[0029] The acquisition module is used to obtain the restored signals corresponding to all target point information after completing the equalization processing of all target point information.

[0030] In a third aspect, an electronic device is provided, including:

[0031] one or more processors;

[0032] Memory;

[0033] One or more applications, wherein one or more applications are stored in a memory and configured to be executed by one or more processors, and one or more programs are configured to: perform operations corresponding to the method shown in any possible implementation of the first aspect.

[0034] In a fourth aspect, a computer-readable storage medium is provided, wherein the storage medium stores at least one instruction, at least one program, a code set or an instruction set, and the at least one instruction, at least one program, a code set or an instruction set is loaded by a processor and executes the steps of the method shown in any possible implementation of the first aspect.

[0035] In a fifth aspect, a computer program product is provided, comprising a computer program, wherein when the computer program is executed by a processor, operations corresponding to the method shown in any possible implementation manner in the first aspect are implemented.

[0036] In summary, the method for restoring a four-dimensional modulated signal provided by the present application includes the following beneficial technical effects:

[0037] An input signal sequence and an original transmission signal sequence are obtained, wherein both the input signal sequence and the original transmission signal sequence are normalized four-dimensional modulated signal sequences; for each target point information of the input signal sequence, the filter tap coefficient corresponding to the target point information and the phase information required for phase compensation corresponding to the target point information are obtained, wherein the filter tap coefficient corresponding to the target point information is obtained based on the filter tap coefficient corresponding to the previous target point information and the original transmission signal sequence, and the phase information corresponding to the target point information is obtained based on the phase information corresponding to the previous target point information and the original transmission signal sequence; nonlinear signal equalization of a MIMO nonlinear equalizer is performed according to the target point information and the filter tap coefficient to obtain an equalized output signal; phase compensation is performed according to the equalized output signal and the phase information to obtain a restored signal; after the equalization processing of all target point information is completed, the restored signals corresponding to all target point information are obtained.

[0038] In this scheme, after obtaining the normalized input signal sequence and the original transmitted signal sequence, for each target point information in the input signal sequence, the corresponding filter tap coefficient and the phase information required for phase compensation are dynamically obtained, the filter tap coefficient is updated based on the filter tap coefficient of the previous target point information and the original transmitted signal sequence, and the phase information corresponding to the target point information is updated based on the phase information of the previous target point information and the original transmitted signal sequence, thereby realizing low-complexity and robust phase estimation for irregular constellation points of four-dimensional modulation; utilizing a MIMO nonlinear equalizer, nonlinear signal equalization is performed in combination with the target point information and the filter tap coefficient, thereby effectively eliminating nonlinear distortion in the signal; performing phase compensation based on the equalized output signal and phase information to obtain a recovered signal, and performing phase recovery while performing multi-dimensional equalization, thereby reducing the impact of equalization-enhanced phase noise and improving the transmission reliability of four-dimensional modulated signals.

[0039] In addition, the present application also provides a four-dimensional modulated signal recovery device, equipment, medium and product, all of which have the above-mentioned beneficial technical effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present application or the technical solutions of the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0041] Figure 1 It is a flowchart of a method for recovering a four-dimensional modulated signal provided in an embodiment of the present application;

[0042] Figure 2 It is a main flow chart of a nonlinear equalization and phase recovery algorithm for a four-dimensional modulated signal provided in an embodiment of the present application;

[0043] Figure 3 It is a schematic diagram of another process of recovering a four-dimensional modulation signal provided in an embodiment of the present application;

[0044] Figure 4 It is a structural schematic diagram of a four-dimensional modulation signal recovery device provided in an embodiment of the present application;

[0045] Figure 5 It is a structural schematic diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, a person skilled in the art may make non-creative modifications to the present embodiment as needed, but such modifications are protected by the patent law as long as they are within the scope of the present application.

[0047] It should be noted that in the optional embodiments of the present application, the object information and other related data involved, when the embodiments in the present application are applied to specific products or technologies, need to obtain the permission or consent of the object, and the collection, use and processing of the relevant data need to comply with the relevant laws, regulations and standards of the relevant countries and regions. In other words, if the embodiments of the present application involve data related to the object, it needs to be obtained with the authorization and consent of the object, the authorization and consent of the relevant departments, and in compliance with the relevant laws, regulations and standards of the country and region. If personal information is involved in the embodiments, the acquisition of all personal information needs to obtain the consent of the individual. If sensitive information is involved, the separate consent of the information subject needs to be obtained. The embodiments also need to be implemented with the authorization and consent of the object.

[0048] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0049] In addition, the term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article, unless otherwise specified, generally means that the associated objects before and after are in an "or" relationship.

[0050] In polarization multiplexing coherent optical communication systems, the use of four-dimensional modulation formats can bring higher spectral efficiency. However, four-dimensional modulated signals face problems such as inter-polarization crosstalk, IQ imbalance, multi-dimensional nonlinear distortion, and phase noise of irregular constellation points that are difficult to compensate.

[0051] The embodiments of the present application relate to the field of optical fiber communications, and specifically to a nonlinear equalization and phase recovery algorithm suitable for a four-dimensional modulated signal. The embodiments of the present application propose a four-dimensional modulated signal processing algorithm that combines a multiple-input multiple-output (MIMO) real-valued equalizer (RVE) with a decision-directed carrier phase estimation (DDCPE). On the one hand, the MIMO-RVE architecture is used to effectively compensate for polarization crosstalk, IQ imbalance, and nonlinear distortion. On the other hand, a decision-directed recursive carrier phase estimation algorithm is used to achieve low-complexity and robust phase estimation for irregular constellation points of four-dimensional modulation. The algorithm performs phase recovery while performing multi-dimensional equalization, which reduces the impact of equalization-enhanced phase noise and improves the transmission reliability of four-dimensional modulated signals in polarization-multiplexed coherent optical communication systems.

[0052] Specifically, the present application embodiment provides a method for recovering a four-dimensional modulated signal, such as Figure 1 As shown, the method provided in the embodiment of the present application can be executed by an electronic device, and the method includes:

[0053] S101, obtaining an input signal sequence and an original transmission signal sequence, where both the input signal sequence and the original transmission signal sequence are normalized four-dimensional modulation signal sequences;

[0054] In the embodiment of the present application, the original transmission signal sequence is a training symbol. The input signal sequence and the original transmission signal sequence are respectively , the corresponding lengths are , using a second-order 4×4 real-valued MIMO nonlinear equalizer, the corresponding initial input signal sequence and the initial original transmission signal sequence The I and Q signals from the X polarization direction and the I and Q signals from the Y polarization direction are the I initial input signal sequence from the X polarization direction and the initial original transmission signal sequence. , For example, the normalized expression is:

[0055] ;

[0056] Where k is the serial number of each point in the signal sequence.

[0057] S102, for each target point information of the input signal sequence, obtaining a filter tap coefficient corresponding to the target point information and phase information required for phase compensation corresponding to the target point information;

[0058] Among them, the filter tap coefficient corresponding to the target point information is obtained according to the filter tap coefficient corresponding to the previous target point information and the original transmission signal sequence, and the phase information corresponding to the target point information is obtained according to the phase information corresponding to the previous target point information and the original transmission signal sequence;

[0059] In one achievable method, each target point information is the information of the target point n in the input signal sequence. For the selection of the target point, the target point information of the input signal sequence can be determined according to the input signal sequence through a sliding window according to a preset sliding distance. The sliding window size is the length of the first-order tap coefficient of the MIMO nonlinear equalizer. According to the preset sliding distance, the middle point of the sliding window is determined as the target point, and the information of the middle point in the input signal sequence is used as the target point information. For example, if the input signal sequence has 10,000 points, the first-order tap coefficient is 101, and the preset sliding distance is 1, then the first sliding window is 1-101, and the first target point is the 51st point; the sliding window corresponding to the second target point is 2-102, and the second target point is the 52nd point, and so on.

[0060] The phase information required for the filter tap coefficients corresponding to the target point information and the phase compensation corresponding to the target point information.

[0061] In one possible case, when the target point information is the first target information point, the filter tap coefficient corresponding to the target point information is the initial filter tap coefficient, and the phase information corresponding to the target point information is the initial phase information; the first-order tap coefficient in the initial filter tap coefficient is The middle position of is assigned a value of 1, and the other values ​​are set to 0; the initial phase information is determined according to the phase difference between the middle point information of the original transmitted signal sequence and the corresponding position information of the input signal sequence.

[0062] The second-order 4×4 real-valued MIMO nonlinear equalizer contains 16 equalizers, corresponding to the permutations and combinations of the I and Q signals in the X polarization direction and the I and Q signals in the Y polarization direction. The middle position of is assigned a value of 1, the other values ​​are set to 0, and the remaining tap coefficients are all 0. For example, it means that the first-order input is I-path in the X polarization direction, and the output is also I-path in the X polarization direction.

[0063] Here, the first-order tap coefficient of I path with both input and output in the X polarization direction is For example, the expression is: , where m is the number of bits in the tap coefficient.

[0064] Initial phase deviation The phase information of the signal at the middle position of the original transmitted signal sequence The phase of the signal at the corresponding position of the input signal sequence The phase difference is determined by: , . are the phase in the X polarization direction and the phase in the Y polarization direction of the initial phase deviation respectively; are respectively the phase in the X polarization direction and the phase in the Y polarization direction of the signal at the middle position of the original transmitted signal sequence; They are respectively the phase in the X polarization direction and the phase in the Y polarization direction of the signal at the middle position of the input signal sequence.

[0065] In another possible situation, when the target point information is not the first target information point, the filter tap coefficient corresponding to the target point information is obtained based on the filter tap coefficient corresponding to the previous target point information and the original transmitted signal sequence, and the phase information corresponding to the target point information is obtained based on the phase information corresponding to the previous target point information and the original transmitted signal sequence.

[0066] S103, performing nonlinear signal equalization of a MIMO nonlinear equalizer according to the target point information and the filter tap coefficients to obtain an equalized output signal;

[0067] In an embodiment of the present application, nonlinear signal equalization of a MIMO nonlinear equalizer is performed according to target point information and filter tap coefficients, and polarization crosstalk, IQ imbalance, and nonlinear distortion are effectively compensated based on a MIMO-RVE architecture. The MIMO nonlinear equalizer is not limited, and users can select it according to actual needs. For example, the MIMO nonlinear equalizer is a MIMO Volterra nonlinear equalizer.

[0068] The balanced output signal is in complex form, including: , n is the target point number corresponding to the target point information. Among them: ; is the balanced output signal in the X polarization direction; is the balanced output signal of the I path in the X polarization direction; It is the balanced output signal of the Q path in the X polarization direction; is the balanced output signal in the Y polarization direction; is the balanced output signal of the I path in the Y polarization direction; It is the balanced output signal of the Q path in the Y polarization direction.

[0069] S104, performing phase compensation according to the equalized output signal and phase information to obtain a restored signal;

[0070] In the embodiment of the present application, the corresponding equalization result is obtained Then, the phase estimation result is used Perform phase compensation to obtain a restored signal, the restored signal includes: a restored signal in the X polarization direction and the recovered signal in the Y polarization direction , the calculation expression is: .

[0071] S105. After the equalization processing of all target point information is completed, the restored signals corresponding to all target point information are obtained.

[0072] It can be seen that in the embodiment of the present application, after obtaining the normalized input signal sequence and the original transmitted signal sequence, for each target point information in the input signal sequence, the corresponding filter tap coefficient and the phase information required for phase compensation are dynamically obtained, the filter tap coefficient is updated based on the filter tap coefficient of the previous target point information and the original transmitted signal sequence, and the phase information corresponding to the target point information is updated based on the phase information of the previous target point information and the original transmitted signal sequence, thereby realizing low-complexity and robust phase estimation for irregular constellation points of four-dimensional modulation; utilizing a MIMO nonlinear equalizer, nonlinear signal equalization is performed in combination with the target point information and the filter tap coefficient, thereby effectively eliminating nonlinear distortion in the signal; performing phase compensation based on the equalized output signal and the phase information to obtain a recovered signal, and performing phase recovery while performing multi-dimensional equalization, thereby reducing the impact of equalization-enhanced phase noise and improving the transmission reliability of the four-dimensional modulated signal.

[0073] Furthermore, the transmission reliability of four-dimensional modulated signals in polarization-multiplexed coherent optical communication systems can be improved.

[0074] In a possible implementation of the embodiment of the present application, S103 performs nonlinear signal equalization of the MIMO nonlinear equalizer according to the target point information and the filter tap coefficient to obtain an equalized output signal, including: S1031-S1033 (not shown in the drawings), wherein:

[0075] S1031, generating a first-order kernel and a second-order kernel of a MIMO nonlinear equalizer corresponding to the target point information according to the target point information;

[0076] S1032, performing signal equalization according to the first-order kernel and the second-order kernel of the MIMO nonlinear equalizer corresponding to the target point information and the filter tap coefficients to obtain a first equalized output signal;

[0077] In the embodiment of the present application, the first-order kernels of the I-path and Q-path signals of the input signal sequences in the X polarization direction and the Y polarization direction are respectively obtained. and the second-order kernel Then it is sent to the equalizer and multiplied by the corresponding filter tap coefficient to obtain the first balanced output signal of I and Q paths in the X and Y polarization directions. , , , , the calculation expression is:

[0078] ;

[0079] 1033. Combine the first balanced output signal in the X polarization direction and the Y polarization direction to obtain a second balanced output signal as the balanced output signal.

[0080] Combine the I and Q balanced output signals in the X polarization direction, and combine the balanced output signals in the Y polarization direction. Thus, the balanced output signals in the X and Y polarization directions are obtained. and , the calculation expression is: , .

[0081] In a possible implementation of the embodiment of the present application, after performing nonlinear signal equalization of the MIMO nonlinear equalizer according to the target point information and the filter tap coefficients to obtain the equalized output signal, S103 further includes: SA1-SA3 (not shown in the drawings), wherein:

[0082] SA1, calculating an error signal corresponding to the target point information according to the equalized output signal corresponding to the target point information and the original target point transmission information corresponding to the target point information in the original transmission signal sequence;

[0083] Among them, the balanced output signal in the X and Y polarization directions is calculated respectively , The original transmitted signal corresponding to , difference and , as the error signal, the calculation expression is as follows: , .

[0084] SA2, performing phase estimation based on the error signal corresponding to the target point information and the phase information corresponding to the target point information, and determining the phase information corresponding to the next target point information;

[0085] According to the error signal corresponding to the target point information and the phase information corresponding to the target point information, the phase deviations in the X polarization direction and the Y polarization direction of the next target point information n+1 are iteratively calculated based on the LMS algorithm. , , the iterative calculation expression is as follows: , ;in, It is the iterative step size parameter of the phase estimation algorithm. It is a positive number and can be set by the user. For example, e -3 、e -5 etc., Im is the imaginary part of the complex number in the brackets, and * is the conjugate complex number of the complex number in the brackets.

[0086] SA3. Determine the filter tap coefficient corresponding to the next target point information based on the error signal corresponding to the target point information and the filter tap coefficient corresponding to the target point information.

[0087] Specifically, the complex error signals in the X-path and Y-path polarization directions are decomposed into real-valued I-path and Q-path error signals, respectively, and the expressions are as follows: , , ; Among them, Re is the real part of the complex number in the brackets, and Im is the imaginary part of the complex number in the brackets.

[0088] According to the LMS algorithm, update the weights of the first-order tap coefficients and the second-order tap coefficients of the filter to obtain the filter tap coefficients corresponding to the next target point information Taking the first-order tap coefficient as an example, the expression is as follows:

[0089] ; in, It is the step size parameter of the equalization algorithm, which is a positive number and can be set by the user. The number of times the tap coefficient is updated is determined by the known length of the original transmitted signal sequence.

[0090] A possible implementation of the embodiment of the present application, after completing the equalization processing of all target point information and obtaining the restored signals corresponding to all target point information, further includes: generating a restored signal sequence according to the restored signals corresponding to all target point information; normalizing the restored signal sequence to obtain a normalized signal sequence. When all elements in the signal sequence are equalized and phase compensated, the restored signal sequence is normalized to obtain a normalized signal sequence. , its calculation expression is: , .

[0091] Furthermore, after completing the training for the input signal sequence, the final filter tap coefficients can be obtained as filter parameters, so that after obtaining the normalized input signal sequence to be processed, the input signal sequence to be processed can be directly processed according to the final filter tap coefficients.

[0092] Furthermore, after completing the training for the input signal sequence, the final phase information can be obtained as the parameter of the filter, so that after obtaining the normalized input signal sequence to be processed, the input signal sequence to be processed can be directly processed according to the final phase information.

[0093] Furthermore, after completing the training for the input signal sequence, the final phase information and the final filter tap coefficients can be obtained as the parameters of the filter, so that after obtaining the normalized input signal sequence to be processed, the input signal sequence to be processed can be directly processed according to the final phase information and the final filter tap coefficients.

[0094] Based on any of the above embodiments, the embodiments of the present application provide a specific nonlinear equalization and phase recovery equalization method for four-dimensional modulated signals, which, while compensating for polarization crosstalk, IQ imbalance and nonlinear distortion, achieves low-complexity and robust phase estimation for irregular constellation points of four-dimensional modulation, thereby realizing large-capacity, highly reliable coherent optical communication of four-dimensional modulated signals.

[0095] See also Figure 2 Taking the MIMO Volterra nonlinear equalizer as an example, the four-dimensional modulated signal recovery method provided in the embodiment of the present application includes the following: normalizing the input signal sequence, initializing the equalization weight matrix and calculating the initial phase of the phase estimation. The signal sequences of the I and Q signals from the X polarization direction and the I and Q signals from the Y polarization direction are calculated. After the real-valued MIMO Volterra series is obtained, it is merged into a complex signal in the X / Y polarization direction. After calculating the error between the corresponding complex signal and the transmitted signal, the least mean square (LMS) algorithm is used to implement recursive phase estimation. After phase estimation, the complex error signal sequence in the X and Y polarization directions is restored to the real error signal sequence of the I and Q paths in the X / Y polarization direction to update the weight matrix. Repeat the above process until the phase estimation of all symbols in the signal sequence and the update of the corresponding weight vector are completed. Equalization and phase compensation are performed according to the updated weight matrix and phase estimation results to obtain the recovered signal, which is output after normalization.

[0096] Specifically, Figure 3 A step diagram of a method for restoring a four-dimensional modulated signal provided for the implementation of this application, the specific implementation of the algorithm includes:

[0097] Step 1: Normalize the signal sequence. Assume that the initial input signal sequence and the initial original transmission signal sequence are , the corresponding lengths are Here, a second-order 4×4 real-valued MIMO Volterra nonlinear equalizer is used. The corresponding initial input signal sequence and the initial original transmission signal sequence are the I and Q signals from the X polarization direction and the I and Q signals from the Y polarization direction. Here, the I-path received signal sequence and the transmission signal sequence from the X polarization direction are used. For example, the normalized expression is as follows: , ;

[0098] Step 2: Initialize the filter tap coefficients and phase information required for phase compensation contained in the equalizer. The second-order 4×4 real-valued MIMO Volterra nonlinear equalizer contains 16 equalizers, corresponding to the permutations and combinations of the I and Q signals in the X polarization direction and the I and Q signals in the Y polarization direction. Only the first-order filter tap coefficients are initialized. , , , The middle position is assigned a value of 1 and the other values ​​are set to 0. Here, the first-order tap coefficient of I path with both input and output in the X polarization direction is For example, the expression is: , .

[0099] The initial phase deviation is determined by the phase difference between the signal at the middle position of the original transmitted signal sequence and the signal at the corresponding position of the input signal sequence, and the expression is: , ;

[0100] Step 3: Calculate the first-order Volerra kernel and second-order Volterra kernel of the input signal sequence.

[0101] According to the Volterra series, the first-order Volterra kernels of the I and Q signals of the input signal sequences in the X polarization direction and the Y polarization direction are obtained respectively. and the second-order Volterra kernel Then it is sent to the equalizer and multiplied by the corresponding filter tap coefficient to obtain the balanced output signals of I and Q paths in the X and Y polarization directions. , the calculation expression is:

[0102] ;

[0103] Step 4: Combine the I and Q balanced output signals in the X polarization direction, and the same goes for the balanced output signals in the Y polarization direction. Thus, the balanced output signals in the X and Y polarization directions are obtained. , the calculation expressions include: , ;

[0104] Step 5: Calculate the error signal. Calculate the equalized output signal in the X and Y polarization directions and the corresponding original transmission signal , The difference, and , the calculation expressions include: , ; Through this error signal, the phase information and filter tap coefficients corresponding to the next target point can be calculated.

[0105] Step 6: Phase estimation. Based on the error signal and the phase deviation corresponding to the point of initial phase deviation / n-1 obtained in step 2, the phase deviation of the X polarization direction and the Y polarization direction of the current input signal are iteratively calculated based on the LMS algorithm. , ,

[0106] Taking the previous target point n-1 as an example, the iterative calculation expression is as follows: , .

[0107] in, is the iterative step size parameter of the phase estimation algorithm, Im is the imaginary part of the complex number in the brackets, and * is the conjugate complex number of the complex number in the brackets.

[0108] Step 7: IQ decomposition of error signal. Decompose the complex error signals in the X-path and Y-path polarization directions into real-valued I-path and Q-path error signals respectively, in preparation for determining the tap coefficient or phase information of the next target point. The expression is as follows:

[0109] ;

[0110] Among them, Re is the real part of the complex number in the brackets, and Im is the imaginary part of the complex number in the brackets.

[0111] Step 8: Update the tap coefficients. According to the LMS algorithm, update the weights of the first-order tap coefficients and the second-order tap coefficients of the filter as the tap coefficients of the filter at the next target point. Taking the first-order tap coefficients as an example, the expression is:

[0112] ;

[0113] in, is the step size parameter of the equalization algorithm. The number of times the tap coefficients are updated is determined by the known length of the original transmitted signal sequence.

[0114] Step 9: Substitute the first-order and second-order tap coefficients of the final updated filter to obtain the corresponding equalization result and , and then use the phase estimation result , Perform phase compensation to obtain the recovered signal, and the calculation expression is: , .

[0115] Step 10: Repeat the above steps until all target elements in the signal sequence are equalized and phase compensated, and normalize the restored signal sequence. The expression is: , .

[0116] The following is an introduction to a device provided in an embodiment of the present application. The device described below and the method described above can be referred to each other. The device of this embodiment is set in an electronic device. Figure 4 , Figure 4 It is a structural block diagram of a device of one embodiment of the present application, comprising:

[0117] An acquisition module 210 is used to acquire an input signal sequence and an original transmission signal sequence, where both the input signal sequence and the original transmission signal sequence are normalized four-dimensional modulated signal sequences;

[0118] The equalization and phase compensation module 220 is used to obtain, for each target point information of the input signal sequence, the filter tap coefficient corresponding to the target point information and the phase information required for phase compensation corresponding to the target point information, wherein the filter tap coefficient corresponding to the target point information is obtained based on the filter tap coefficient corresponding to the previous target point information and the original transmitted signal sequence, and the phase information corresponding to the target point information is obtained based on the phase information corresponding to the previous target point information and the original transmitted signal sequence; perform nonlinear signal equalization of the MIMO nonlinear equalizer according to the target point information and the filter tap coefficient to obtain an equalized output signal; perform phase compensation according to the equalized output signal and the phase information to obtain a recovered signal;

[0119] The acquisition module 230 is used to obtain the restored signals corresponding to all target point information after completing the equalization processing of all target point information.

[0120] In one achievable manner, the equalization and phase compensation module 220 includes:

[0121] An equalization unit is used to: generate a first-order kernel and a second-order kernel of a MIMO nonlinear equalizer corresponding to the target point information according to the target point information;

[0122] Perform signal equalization according to the first-order kernel and the second-order kernel of the MIMO nonlinear equalizer corresponding to the target point information, and the filter tap coefficients to obtain a first equalized output signal;

[0123] The first balanced output signal is combined in the X polarization direction and the Y polarization direction to obtain a second balanced output signal as the balanced output signal.

[0124] In one achievable manner, the equalization and phase compensation module 220 includes:

[0125] The error signal determination unit is used to calculate the error signal corresponding to the target point information according to the equalized output signal corresponding to the target point information and the original target point transmission information corresponding to the target point information in the original transmission signal sequence;

[0126] The phase information updating unit is used to: perform phase estimation according to the error signal corresponding to the target point information and the phase information corresponding to the target point information, and determine the phase information corresponding to the next target point information;

[0127] The filter tap coefficient updating unit is used to determine the filter tap coefficient corresponding to the next target point information according to the error signal corresponding to the target point information and the filter tap coefficient corresponding to the target point information.

[0128] In an achievable manner, the equalization and phase compensation module 220 is further configured to:

[0129] According to the input signal sequence, the target point information of the input signal sequence is determined through the sliding window according to the preset sliding distance.

[0130] In an achievable manner, when the target point information is the first target information point, the filter tap coefficient corresponding to the target point information is the initial filter tap coefficient, and the phase information corresponding to the target point information is the initial phase information;

[0131] The first-order tap coefficients in the initial filter tap coefficients , , , The middle position of is assigned a value of 1, and the other values ​​are set to 0;

[0132] The initial phase information is determined according to the phase difference between the midpoint information of the original transmitted signal sequence and the corresponding position information of the input signal sequence.

[0133] In an achievable manner, it further includes: a normalization unit, which is used to: generate a restored signal sequence according to the restored signals corresponding to all target point information; and perform normalization processing on the restored signal sequence to obtain a normalized signal sequence.

[0134] An electronic device is provided in an embodiment of the present application, such as Figure 5 As shown, Figure 5The electronic device 300 shown includes: a processor 301 and a memory 303. The processor 301 and the memory 303 are connected, such as through a bus 302. Optionally, the electronic device 300 may also include a transceiver 304. It should be noted that in actual applications, the transceiver 304 is not limited to one, and the structure of the electronic device 300 does not constitute a limitation on the embodiments of the present application.

[0135] The processor 301 may be a CPU (Central Processing Unit), a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. It may implement or execute various exemplary logic blocks, modules and circuits described in conjunction with the disclosure of this application. The processor 301 may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, etc.

[0136] The bus 302 may include a path to transmit information between the above components. The bus 302 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus. The bus 302 may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 5 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0137] The memory 303 may be a ROM (Read Only Memory) or other types of static storage devices that can store static information and instructions, a RAM (Random Access Memory) or other types of dynamic storage devices that can store information and instructions, or an EEPROM (Electrically Erasable Programmable Read Only Memory), a CD-ROM (Compact Disc Read Only Memory) or other optical disk storage, optical disk storage (including compressed optical disk, laser disk, optical disk, digital versatile disk, Blu-ray disk, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto.

[0138] The memory 303 is used to store the application code for executing the solution of the present application, and the execution is controlled by the processor 301. The processor 301 is used to execute the application code stored in the memory 303 to implement the contents shown in the above method embodiment.

[0139] Figure 5 The electronic device shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0140] An embodiment of the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer-readable storage medium is run on a computer, the computer can execute the corresponding content in the aforementioned method embodiment.

[0141] An embodiment of the present application provides a computer program product, including a computer program, which implements the corresponding contents of the aforementioned method embodiment when the computer program is executed by a processor.

[0142] It should be understood that, although the steps in the flowchart of the accompanying drawings are displayed in sequence as indicated by the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least a part of the steps in the flowchart of the accompanying drawings may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be executed in turn or alternately with other steps or at least a part of the sub-steps or stages of other steps.

[0143] The above are only some implementation methods of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A method for restoring a four-dimensional modulated signal, characterized in that: include: Acquire an input signal sequence and an original transmission signal sequence, wherein both the input signal sequence and the original transmission signal sequence are normalized four-dimensional modulation signal sequences; For each target point information of the input signal sequence, the filter tap coefficient corresponding to the target point information and the phase information required for phase compensation corresponding to the target point information are obtained, wherein the filter tap coefficient corresponding to the target point information is obtained based on the filter tap coefficient corresponding to the previous target point information and the original transmitted signal sequence, and the phase information corresponding to the target point information is obtained based on the phase information corresponding to the previous target point information and the original transmitted signal sequence; nonlinear signal equalization of the MIMO nonlinear equalizer is performed according to the target point information and the filter tap coefficient to obtain an equalized output signal; and phase compensation is performed according to the equalized output signal and the phase information to obtain a recovered signal; After the equalization processing of all target point information is completed, the restored signals corresponding to all target point information are obtained.

2. The method for restoring a four-dimensional modulated signal according to claim 1, characterized in that: The nonlinear signal equalization of the MIMO nonlinear equalizer is performed according to the target point information and the filter tap coefficient to obtain an equalized output signal, including: Generate a first-order kernel and a second-order kernel of a MIMO nonlinear equalizer corresponding to the target point information according to the target point information; Perform signal equalization according to the first-order kernel and the second-order kernel of the MIMO nonlinear equalizer corresponding to the target point information, and the filter tap coefficients to obtain a first equalized output signal; The first balanced output signal is combined in the X polarization direction and the Y polarization direction to obtain a second balanced output signal as the balanced output signal.

3. The method for restoring a four-dimensional modulated signal according to claim 1, characterized in that: After performing nonlinear signal equalization of the MIMO nonlinear equalizer according to the target point information and the filter tap coefficients to obtain an equalized output signal, the method further includes: Calculate an error signal corresponding to the target point information according to the equalized output signal corresponding to the target point information and the original target point transmission information corresponding to the target point information in the original transmission signal sequence; Perform phase estimation based on the error signal corresponding to the target point information and the phase information corresponding to the target point information, and determine the phase information corresponding to the next target point information; The filter tap coefficient corresponding to the next target point information is determined according to the error signal corresponding to the target point information and the filter tap coefficient corresponding to the target point information.

4. The method for restoring a four-dimensional modulated signal according to claim 1, characterized in that: The process of determining the information of each target point includes: According to the input signal sequence, target point information of the input signal sequence is determined through a sliding window according to a preset sliding distance.

5. The method for restoring a four-dimensional modulated signal according to claim 1, characterized in that: When the target point information is the first target information point, the filter tap coefficient corresponding to the target point information is the initial filter tap coefficient, and the phase information corresponding to the target point information is the initial phase information; The first-order tap coefficients in the initial filter tap coefficients , , , The middle position of is assigned a value of 1, and the other values ​​are set to 0; The initial phase information is determined according to the phase difference between the midpoint information of the original transmitted signal sequence and the corresponding position information of the input signal sequence.

6. The method for restoring a four-dimensional modulated signal according to claim 1, characterized in that: After completing the equalization processing of all target point information and obtaining the restored signals corresponding to all target point information, the method further includes: Generate a recovery signal sequence according to the recovery signals corresponding to all target point information; The restored signal sequence is normalized to obtain a normalized signal sequence.

7. A device for recovering a four-dimensional modulated signal, characterized in that: include: An acquisition module, used to acquire an input signal sequence and an original transmission signal sequence, wherein both the input signal sequence and the original transmission signal sequence are normalized four-dimensional modulation signal sequences; An equalization and phase compensation module is used to obtain, for each target point information of the input signal sequence, the filter tap coefficient corresponding to the target point information and the phase information required for phase compensation corresponding to the target point information, wherein the filter tap coefficient corresponding to the target point information is obtained based on the filter tap coefficient corresponding to the previous target point information and the original transmitted signal sequence, and the phase information corresponding to the target point information is obtained based on the phase information corresponding to the previous target point information and the original transmitted signal sequence; nonlinear signal equalization of the MIMO nonlinear equalizer is performed according to the target point information and the filter tap coefficient to obtain an equalized output signal; and phase compensation is performed according to the equalized output signal and the phase information to obtain a recovered signal; The acquisition module is used to obtain the restored signals corresponding to all target point information after completing the equalization processing of all target point information.

8. An electronic device, characterized in that: include: one or more processors; Memory; One or more applications, wherein the one or more applications are stored in the memory and configured to be executed by the one or more processors, and the one or more applications are configured to: execute the steps of the four-dimensional modulated signal recovery method according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that: The storage medium stores at least one instruction, at least one program, code set or instruction set, and the at least one instruction, at least one program, code set or instruction set is loaded by the processor and executes the steps of the four-dimensional modulated signal recovery method according to any one of claims 1 to 6.

10. A computer program product, characterized in that It comprises a computer program, which, when executed by a processor, implements the steps of the method for restoring a four-dimensional modulated signal as claimed in any one of claims 1 to 6.

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