A method, device, equipment, medium and product for recovering four-dimensional modulated signals

Abstract

The present application relates to the field of optical fiber communications, and in particular to a method, apparatus, device, medium, and product for recovering four-dimensional modulated signals. The method comprises: dynamically obtaining, for each target point information, its corresponding filter tap coefficient and phase information required for phase compensation, wherein 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 achieving low-complexity and robust phase estimation for irregular constellation points of four-dimensional modulation; utilizing a MIMO nonlinear equalizer to perform nonlinear signal equalization in combination with the target point information and the filter tap coefficient; performing phase compensation based on the equalized output signal and the phase information, and performing phase recovery simultaneously with multi-dimensional equalization, thereby reducing the impact of equalization-enhanced phase noise and improving the transmission reliability of the four-dimensional modulated signal.

Description

Technical Field

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

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

[0003] However, the two-dimensional projected constellation points of many four-dimensional modulation formats are irregular, which results in poor phase estimation performance of traditional carrier phase estimation algorithms for standard QAM / PSK constellations, such as blind phase search, when performing 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 this application is to provide a method, device, equipment, medium and product for recovering four-dimensional modulated signals, 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 the input signal sequence and the original transmission signal sequence are both normalized four-dimensional modulated signal sequences;

[0008] For each target point information of the input signal sequence, a filter tap coefficient corresponding to the target point information and 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 a MIMO nonlinear equalizer is performed based on the target point information and the filter tap coefficient to obtain an equalized output signal; and phase compensation is performed based on 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 the 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 method further includes:

[0015] Calculating an error signal corresponding to the target point information based on 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 information of each target point includes:

[0019] The target point information of the input signal sequence is determined according to the input signal sequence 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 coefficient in the initial filter tap coefficients 、 、 、 The middle position 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 comprises:

[0024] Generate a restored signal sequence according to the restored 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, configured 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 modulated signal sequences;

[0028] an equalization and phase compensation module, configured to obtain, for each target point information of the input signal sequence, a filter tap coefficient corresponding to the target point information and 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 a MIMO nonlinear equalizer based on the target point information and the filter tap coefficient to obtain an equalized output signal; and perform phase compensation based on 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] According to a third aspect, an electronic device is provided, including:

[0031] one or more processors;

[0032] Memory;

[0033] One or more applications, wherein the one or more applications are stored in a memory and configured to be executed by one or more processors, and the 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, code set or instruction set, and the at least one instruction, at least one program, code set or 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, which, when executed by a processor, implements operations corresponding to the method shown in any possible implementation manner in the first aspect.

[0036] In summary, the method for recovering a four-dimensional modulated signal provided by this application has the following beneficial technical effects:

[0037] An input signal sequence and an original transmission signal sequence are obtained, where 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 the MIMO nonlinear equalizer is performed based on the target point information and the filter tap coefficient to obtain an equalized output signal; phase compensation is performed based on the equalized output signal and the phase information to obtain a recovered signal; after completing the equalization processing of all target point information, the recovered 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 target point information and filter tap coefficients, effectively eliminating nonlinear distortion in the signal; phase compensation is performed based on the equalized output signal and phase information to obtain a recovered signal, and phase recovery is performed simultaneously with multi-dimensional equalization, thereby reducing the impact of equalization-enhanced phase noise and improving the transmission reliability of the four-dimensional modulated signal.

[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 following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

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

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

[0043] Figure 3 This is a schematic diagram of another process for recovering a four-dimensional modulated signal provided by an embodiment of the present application;

[0044] Figure 4 1 is a schematic structural diagram of a four-dimensional modulated signal recovery device provided in an embodiment of the present application;

[0045] Figure 5 This is a structural 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, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the present application, they are protected by patent law.

[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 through 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 requires 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] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0049] In this document, the term "and / or" simply describes a relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document, unless otherwise specified, generally indicates an "or" relationship between the related objects.

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

[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 applicable to 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 inter-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, 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 embodiment of the present application 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 performed 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 modulated 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 transmitted 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 initial input signal sequence of the I channel from the X polarization direction and the initial original transmission signal sequence. 、 For example, the normalized expression is:

[0055] ;

[0056] Where k is the sequence 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 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;

[0059] In one achievable method, each target point information is information about target point n in the input signal sequence. For target point selection, the target point information of the input signal sequence can be determined based on the input signal sequence using a sliding window according to a preset sliding distance. The sliding window size is equal to 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 about 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 coefficient 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 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 an I-path in the X-polarization direction, and the output is also an I-path in the X-polarization direction.

[0063] Here we take the first-order tap coefficient of I path with both input and output in the X polarization direction as 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 in 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 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, respectively; 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 this embodiment of the present application, a MIMO nonlinear equalizer performs nonlinear signal equalization based on target point information and filter tap coefficients, effectively compensating for inter-polarization crosstalk, IQ imbalance, and nonlinear distortion based on a MIMO-RVE architecture. The MIMO nonlinear equalizer is not limited and can be selected by the user based on actual needs. Exemplarily, 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 channel 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 channel I 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 the restored signal, which includes: the restored signal in the X polarization direction and the recovered signal in the Y polarization direction , the calculation expression is: .

[0071] S105 , after completing the equalization processing of all target point information, obtaining the restored signals corresponding to all target point information.

[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 target point information and filter tap coefficients, 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 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 a MIMO nonlinear equalizer according to target point information and filter tap coefficients 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 obtained respectively. 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 the Y polarization direction. This will give the balanced output signals in the X and Y polarization directions. 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. Calculate an error signal corresponding to the target point information based on 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 signals in the X and Y polarization directions are 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] Among them, according to the error signal corresponding to the target point information and the phase information corresponding to the target point information, the phase deviation in the X polarization direction and the Y polarization direction of the next target point information n+1 is 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, which is a positive number and can be customized by the user, such as 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-valued error signals in the X-path and Y-path polarization directions are decomposed into real-valued I-path and Q-path error signals, respectively, as expressed by: 、 、 ; 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 coefficient and the second-order tap coefficient of the filter to obtain the filter tap coefficient corresponding to the next target point information Taking the first-order tap coefficient as an example, the expression is as follows:

[0089] ;in, The step size parameter of the equalization algorithm is a positive number that can be customized by the user. The number of times the tap coefficients are 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 based on 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 filter parameter, 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 inter-polarization crosstalk, IQ imbalance, and nonlinear distortion, achieves low-complexity and robust phase estimation for irregular constellation points of four-dimensional modulation, thereby realizing high-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 by the embodiment of the present application includes the following steps: 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 channels in the X polarization direction and the I and Q channels in the Y polarization direction are calculated. After the real-valued MIMO Volterra series are calculated, they are combined into complex signals in the X / Y polarization directions. After calculating the error between the corresponding complex signals and the transmitted signal, recursive phase estimation is performed using the least mean square (LMS) algorithm. After phase estimation, the complex error signal sequences in the X and Y polarization directions are restored to real error signal sequences in the I and Q paths in the X / Y polarization directions to update the weight matrix. This process is repeated until the phases of all symbols in the signal sequence are estimated and the corresponding weight vectors are updated. Equalization and phase compensation are performed based on the updated weight matrix and phase estimation results to obtain the recovered signal, which is then normalized and output.

[0096] Specifically, Figure 3 A step diagram of a four-dimensional modulated signal recovery method 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-path and Q-path signals from the X polarization direction and the I-path and Q-path signals from the Y polarization direction. Here, the I-path receiving 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 we take the first-order tap coefficient of I path with both input and output in the X polarization direction as 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 and Y polarization directions are obtained respectively. and the second-order Volterra kernel Then it is sent to the equalizer and multiplied with 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 current input signal in the X polarization direction and the Y polarization direction is 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 the error signal. Decompose the complex error signals in the X- and Y-path polarization directions into real-valued I- and Q-path error signals, respectively, to prepare for determining the tap coefficient or phase information of the next target point. The expressions are 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 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 final updated filter first-order and second-order tap coefficients to obtain the corresponding equalization results 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 recovered 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 referenced to each other. The device of this embodiment is set in an electronic device. Figure 4 , Figure 4 This is a structural block diagram of a device according to one embodiment of the present application, including:

[0117] An acquisition module 210 is configured 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 configured to obtain, for each target point information of the input signal sequence, a filter tap coefficient corresponding to the target point information and 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 based on the target point information and the filter tap coefficient to obtain an equalized output signal; and perform phase compensation based on the equalized output signal and the phase information to obtain a recovered signal;

[0119] The obtaining 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] an error signal determining unit, configured to calculate an error signal corresponding to the target point information based on 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 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;

[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 one achievable manner, the equalization and phase compensation module 220 is further configured to:

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

[0130] In one implementable 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] First-order tap coefficients in the initial filter tap coefficients 、 、 、 The middle position 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 one achievable manner, the method further includes: a normalization unit configured 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, for example, via a bus 302. Optionally, the electronic device 300 may further include a transceiver 304. It should be noted that in actual applications, the number of transceivers 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] Processor 301 can 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 device, transistor logic device, hardware component, or any combination thereof. It can implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. Processor 301 can 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] Bus 302 may include a path for transmitting information between the above components. Bus 302 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus. Bus 302 may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, Figure 5 Only one thick line is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0137] The memory 303 may be a ROM (Read Only Memory) or other type of static storage device that can store static information and instructions, a RAM (Random Access Memory) or other type of dynamic storage device 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 compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store 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 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 content shown in the above method embodiment.

[0139] Figure 5 The electronic device shown is merely an example and should not limit 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 having a computer program stored thereon. When the computer-readable storage medium is run on a computer, the computer can execute the corresponding contents of 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 flowcharts of the accompanying drawings are shown in sequence as indicated by the arrows, these steps are not necessarily executed 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 some of the steps in the flowcharts 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 portion of the sub-steps or stages of other steps.

[0143] The above are only some of the 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 recovering a four-dimensional modulated signal, characterized in that: include: Acquire an input signal sequence and an original transmission signal sequence, wherein the input signal sequence and the original transmission signal sequence are both normalized four-dimensional modulated signal sequences; For each target point information of the input signal sequence, a filter tap coefficient corresponding to the target point information and 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 a MIMO nonlinear equalizer is performed based on the target point information and the filter tap coefficient to obtain an equalized output signal; and phase compensation is performed based on 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, wherein: The performing 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 includes: 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, wherein: 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: Calculating an error signal corresponding to the target point information based on 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, wherein: The process of determining the information of each target point includes: The target point information of the input signal sequence is determined according to the input signal sequence through a sliding window according to a preset sliding distance.

5. The method for restoring a four-dimensional modulated signal according to claim 1, wherein: 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 coefficients 、 、 、 The middle position 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, wherein: 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 restored signal sequence according to the restored 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, configured 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 modulated signal sequences; an equalization and phase compensation module, configured to obtain, for each target point information of the input signal sequence, a filter tap coefficient corresponding to the target point information and 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 a MIMO nonlinear equalizer based on the target point information and the filter tap coefficient to obtain an equalized output signal; and perform phase compensation based on 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 The invention comprises a computer program, which implements the steps of the method for recovering a four-dimensional modulated signal as claimed in any one of claims 1 to 6 when the computer program is executed by a processor.

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