SNR compensation method and system in MPI interference under PAM4

Abstract

The invention provides an SNR (Signal to Noise Ratio) compensation method and system under PAM4 (Pulse Amplitude Modulation 4) MPI (Maximum Power Interface) interference. The method comprises the following steps: S1, collecting balanced sampling data on a level and updating a corresponding statistical histogram statistical result; s2, respectively calculating a mean value, a standard deviation and a kurtosis value corresponding to each group of levels according to a statistical result of the statistical histogram; s3, compensating the standard deviation through the kurtosis value, calculating the calibrated standard deviation on the level, and calculating a Q value according to the mean value and the calibrated standard deviation; and S4, calculating respective corresponding bit error rates according to the Q values, and taking a mean value to obtain a current bit error rate statistical value of the optical module. According to the method, quantitative calculation of different dimensions is carried out on data distribution, quantitative description can be carried out on the non-Gaussian degree of data, then an SNR compensation value is obtained, and the problem that SNR estimation deviation is large under MPI interference is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of communication, in particular to a SNR compensation method and system under MPI interference of PAM4. BACKGROUND

[0002] The traditional Q value algorithm can better solve the SNR estimation under NRZ and the SNR estimation under PAM4 general scene. But for the MPI interference problem under PAM4, the traditional Q value algorithm will have a large estimation deviation, and the stronger the MPI is, the larger the deviation is, which will lead to misjudgment of the actual performance and its change of the link.

[0003] The fitting-based Q value algorithm can solve the estimation deviation problem of the traditional Q value algorithm under MPI interference to some extent, but the fitting algorithm itself has poor stability, and needs to recalibrate the fitting parameters when the actual environment changes. At the same time, the fitting algorithm itself needs to be calculated several times to select the optimal quality, resulting in very large memory and calculation overheads.

[0004] The Q value algorithm model of SNR estimation is based on the assumption that the residual noise after equalization is high-strength, when there is MPI interference, the data in the link introduces non-Gaussian interference after equalization, which leads to the problem of large SNR estimation deviation. SUMMARY

[0005] In view of the defects in the prior art, the purpose of the present application is to provide a SNR compensation method and system under MPI interference of PAM4.

[0006] According to the SNR compensation method under MPI interference of PAM4 provided by the present application, comprising:

[0007] Step S1: collect the sampling data after equalization on the level and update the corresponding statistical histogram statistical results;

[0008] Step S2: calculate the mean, standard deviation and kurtosis value corresponding to each group of levels according to the statistical histogram statistical results respectively;

[0009] Step S3: compensate the standard deviation by the kurtosis value, calculate the calibrated standard deviation on the level, and calculate the Q value according to the mean and the calibrated standard deviation;

[0010] Step S4: calculate the respective bit error rate according to the Q value and take the mean to obtain the current bit error rate statistical value of the optical module.

[0011] Preferably, in the step S1:

[0012] The PAM4 signal technology adopts four different signal levels for signal transmission, and the software collects the balanced sampling data on each PAM level of PAM4 as needed when there is a free scheduling resource. Each set of PAM level data is stored in the form of statistical histogram statistics results.

[0013] The balanced sampling data is collected multiple times and the corresponding statistical histogram statistics results are updated until the statistical quantity reaches the software threshold.

[0014] Preferably, in the step S2:

[0015] According to the statistical histogram statistics results, the mean μ, the standard deviation σ and the kurtosis value k corresponding to each group of levels are calculated respectively:

[0016]

[0017]

[0018]

[0019] Where i=0, 1, 2, 3, respectively representing the four groups of levels of PAM4 signal; hist is the statistical value of the number of sampling values on each level value in the range of 0-255 levels, and j is the index of the hist statistics result.

[0020] Preferably, in the step S3:

[0021] The kurtosis value is compensated for the standard deviation, and the calibrated standard deviation on the four groups of PAM levels is calculated:

[0022]

[0023] The Q value is calculated according to the mean value and the calibrated standard deviation. The calculation method is to calculate the opening distance d according to the mean value of adjacent PAM, to calculate the noise sigma according to the calibrated standard deviation of adjacent PAM, and the ratio of the two is the Q value. Three Q values are calculated under PAM4:

[0024]

[0025] Where i=0, 1, 2, representing three eyes of PAM4 signal.

[0026] Preferably, in the step S4:

[0027] The three Q values are calculated according to the erfc function to obtain the respective bit error rate ber, and the mean value is taken to obtain the current bit error rate statistical value of the optical module:

[0028]

[0029]

[0030]

[0031] Wherein the coefficients a, b, c are configured by software, and ber_m is the mean value ber calculated by the three eyes.

[0032] According to the present application, a PAM4 SNR compensation system under MPI interference is provided, comprising:

[0033] Module M1: Collecting the sampling data after level equalization and updating the corresponding statistical histogram statistics;

[0034] Module M2: Calculating the mean value, standard deviation and kurtosis value corresponding to each group of levels according to the statistical histogram statistics;

[0035] Module M3: Compensating the standard deviation by the kurtosis value, calculating the calibrated standard deviation after level calibration, and calculating the Q value according to the mean value and the calibrated standard deviation;

[0036] Module M4: Calculating the respective bit error rate according to the Q value and taking the mean value to obtain the current bit error rate statistics of the optical module.

[0037] Preferably, in the module M1:

[0038] The PAM4 signal technology uses 4 different signal levels for signal transmission, and the software collects the sampling data after PAM4 level equalization as needed when there is idle scheduling resource. Each group of PAM level data is stored in the form of statistical histogram statistics.

[0039] The sampling data after equalization is collected multiple times and the corresponding statistical histogram statistics is updated until the statistical amount reaches the software threshold.

[0040] Preferably, in the module M2:

[0041] According to the statistical histogram statistics, the mean value μ, the standard deviation σ and the kurtosis value k corresponding to each group of levels are calculated respectively:

[0042]

[0043]

[0044]

[0045] Wherein, i=0, 1, 2, 3, respectively representing the 4 groups of levels of PAM4 signal; hist is the statistical value of the number of sampling values at each level value in the range of 0-255 levels, and j is the index of the hist statistics.

[0046] Preferably, in the module M3:

[0047] By compensating the standard deviation with the kurtosis value, the standard deviation after calibration of the four groups of PAM levels is calculated:

[0048]

[0049] The Q value is calculated based on the mean and calibrated standard deviation. The calculation method is to calculate the eye opening distance d based on the mean of adjacent PAM and the noise sigma based on the calibrated standard deviation of adjacent PAM. The ratio of the two is the Q value. Three Q values ​​are calculated for PAM4:

[0050]

[0051] Where i = 0, 1, 2, representing the three eyes of the PAM4 signal.

[0052] Preferably, in the module M4:

[0053] The three Q values ​​are calculated using the erfc function to calculate their corresponding bit error rates (BER) and averaged to obtain the current bit error rate statistics of the optical module:

[0054]

[0055]

[0056]

[0057] The coefficients a, b, and c are configured by the software, and ber_m is the mean ber calculated by the three eyes.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] 1. The present invention can quantitatively describe the degree of data non-Gaussianity by performing quantitative calculations on data distribution in different dimensions, and then obtain an SNR compensation value, thereby solving the problem of large SNR estimation deviation under MPI interference.

[0060] 2. The present invention also has a certain effect on SNR estimation deviation under other influences such as high and low temperatures.

[0061] 3. The present invention can output an MPI correction factor as an MPI interference indicator in the link, solving the problem that operation and maintenance personnel cannot judge the MPI interference intensity in the link. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0063] Figure 1System flowchart of the present application. DETAILED DESCRIPTION

[0064] The present application will be described in detail below with specific examples. The following examples will help those skilled in the art to further understand the present application, but in no way limit the present application. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present application. These are within the scope of the present application.

[0065] Example 1

[0066] According to the SNR compensation method for MPI interference under PAM4 provided by the present application, as shown in the formula: Figure 1

[0067] Step S1: Collecting the sampling data after equalization on each level and updating the corresponding statistical histogram statistics;

[0068] Specifically, in the step S1:

[0069] The PAM4 signal technology uses four different signal levels for signal transmission. The software collects the sampling data after equalization on each PAM level as needed when there is idle scheduling resource. Each PAM level data is stored in the form of statistical histogram statistics.

[0070] The sampling data after equalization is collected multiple times and the corresponding statistical histogram statistics is updated until the statistical amount reaches the software threshold.

[0071] Step S2: Calculating the mean, standard deviation and kurtosis value corresponding to each group of levels according to the statistical histogram statistics;

[0072] Specifically, in the step S2:

[0073] According to the statistical histogram statistics, the mean μ, standard deviation σ and kurtosis value k corresponding to each group of levels are calculated:

[0074]

[0075]

[0076]

[0077] Where i=0, 1, 2, 3, respectively representing the four groups of levels of PAM4 signal; hist is the statistical value of the number of sampling values on each level value in the range of 0-255 levels, and j is the index of the hist statistical result.

[0078] ​Step S3: Calculate the standard deviation after calibration of the level by compensating the standard deviation with the kurtosis value, and calculate the Q value according to the mean value and the calibrated standard deviation;

[0079] Specifically, in the step S3:

[0080] Calculate the standard deviation after calibration of the four groups of PAM levels by compensating the standard deviation with the kurtosis value:

[0081]

[0082] Calculate the Q value according to the mean value and the calibrated standard deviation, and the calculation method is to calculate the opening distance d according to the mean value of the adjacent PAM, calculate the noise sigma according to the calibrated standard deviation of the adjacent PAM, and the ratio of the two is the Q value. Three Q values are calculated under PAM4:

[0083]

[0084] Where i=0, 1, 2, represents the three eyes of the PAM4 signal.

[0085] Step S4: Calculate the respective corresponding bit error rate according to the Q value and take the mean value to obtain the current bit error rate statistical value of the optical module.

[0086] Specifically, in the step S4:

[0087] Three Q values are calculated according to the erfc function to calculate the respective corresponding bit error rate ber and take the mean value to obtain the current bit error rate statistical value of the optical module:

[0088]

[0089]

[0090]

[0091] Where the coefficients a, b, and c are configured by software, and ber_m is the mean value ber calculated by the three eyes.

[0092] Embodiment 2:

[0093] Embodiment 2 is a preferred example of Embodiment 1, which more specifically illustrates the present application.

[0094] The present application also provides a SNR compensation system under MPI interference of PAM4, which can be realized by executing the flow steps of the SNR compensation method under MPI interference of PAM4, that is, the SNR compensation method under MPI interference of PAM4 can be understood by those skilled in the art as a preferred embodiment of the SNR compensation system under MPI interference of PAM4.

[0095] According to the application, a SNR compensation system in the presence of MPI interference under PAM4 is provided, comprising:

[0096] Module M1: collect the sampling data after equalization at the level and update the corresponding statistical histogram statistics;

[0097] Specifically, in the module M1:

[0098] The PAM4 signal technology uses four different signal levels for signal transmission. The software collects the sampling data after equalization at each group of PAM levels as needed when there is idle scheduling resource. Each group of PAM level data is stored in the form of statistical histogram statistics.

[0099] The sampling data after equalization is collected multiple times and the corresponding statistical histogram statistics are updated until the statistical quantity reaches the software threshold.

[0100] Module M2: calculate the mean, standard deviation and kurtosis value corresponding to each group of levels according to the statistical histogram statistics;

[0101] Specifically, in the module M2:

[0102] According to the statistical histogram statistics, the mean μ, the standard deviation σ and the kurtosis value k corresponding to each group of levels are calculated:

[0103]

[0104]

[0105]

[0106] Where i=0, 1, 2, 3, respectively representing the four groups of levels of PAM4 signal; hist is the statistical value of the number of sampling values at each level value in the range of 0-255 levels, and j is the index of the hist statistics.

[0107] Module M3: compensate the standard deviation by the kurtosis value, calculate the calibrated standard deviation at the level, and calculate the Q value according to the mean and the calibrated standard deviation;

[0108] Specifically, in the module M3:

[0109] Compensate the standard deviation by the kurtosis value, and calculate the calibrated standard deviation at the four groups of PAM levels:

[0110]

[0111] Q value is calculated according to mean value and calibrated standard deviation, the calculation method is that the opening distance d is calculated according to the mean value of adjacent PAM, the noise sigma is calculated according to the calibrated standard deviation of adjacent PAM, and the ratio of the two is Q value, and three Q values are calculated under PAM4:

[0112]

[0113] Where i = 0, 1, 2, representing the three eyes of the PAM4 signal.

[0114] Module M4: calculate the respective bit error rate according to the Q value and take the mean value to obtain the current bit error rate statistical value of the optical module.

[0115] Specifically, in the module M4:

[0116] The three Q values calculate the respective bit error rate ber according to the erfc function and take the mean value to obtain the current bit error rate statistical value of the optical module:

[0117]

[0118]

[0119]

[0120] Where the coefficients a, b, and c are configured by software, and ber_m is the mean value ber calculated by the three eyes.

[0121] Embodiment 3:

[0122] Embodiment 3 is a preferred example of embodiment 1, which more specifically illustrates the present application.

[0123] Step 1: PAM4 signal technology is a modulation technology that uses four different signal levels for signal transmission. The software collects the equalized sample data on each PAM level of PAM4 as needed when there is idle scheduling resource. Each PAM level data is stored in the form of histogram (histogram, hereinafter referred to as hist) statistical result;

[0124] Step 2: Collect the equalized sample data multiple times and update the corresponding hist statistical result until the statistical amount reaches the software threshold;

[0125] Step 3: Calculate the mean value μ, standard deviation σ, and kurtosis value k corresponding to each group of levels according to the hist statistical result:

[0126]

[0127]

[0128]

[0129] wherein i = 0, 1, 2, 3, respectively, represent 4 groups of levels of PAM4 signal.

[0130] Step 4: Calculate the calibrated standard deviation of 4 groups of PAM levels by compensating the standard deviation by kurtosis value:

[0131]

[0132] Step 5: Calculate Q value according to mean value and calibrated standard deviation, the calculation method is to calculate the open eye distance d according to the mean value of adjacent PAM, calculate the noise sigma according to the calibrated standard deviation of adjacent PAM, and the ratio of the two is the Q value, which can calculate 3 Q values under PAM4:

[0133]

[0134] wherein i = 0, 1, 2, represent 3 eyes of PAM4 signal.

[0135] Step 6: Calculate the bit error ratio (hereinafter referred to as ber) corresponding to each of the 3 Q values according to erfc function and take the mean value to obtain the current ber statistical value of the optical module.

[0136]

[0137]

[0138]

[0139] wherein the coefficients a / b / c can be configured by software.

[0140] Those skilled in the art know that, in addition to implementing the system provided by the present application and each device, module and unit thereof in the form of pure computer readable program code, the system provided by the present application and each device, module and unit thereof can also be implemented in the form of logic gate, switch, special integrated circuit, programmable logic controller and embedded microcontroller by logically programming the method steps to achieve the same function. Therefore, the system provided by the present application and each device, module and unit thereof can be considered as a hardware component, and the devices, modules and units included therein for achieving various functions can also be considered as structures within the hardware component; the devices, modules and units for achieving various functions can also be considered as both software modules for implementing the method and structures within the hardware component.

[0141] The specific embodiments of the present application are described above. It needs to be understood that the present application is not limited to the specific embodiments described above, and various changes or modifications can be made by those skilled in the art within the scope of the claims, which does not affect the essential content of the present application. The embodiments of the present application and the features in the embodiments can be combined with each other at will without conflict.

Claims

1. A method for SNR compensation in the presence of MPI interference for PAM4, characterized in that, Comprise: Step S1: collect the sampling data after equalization on the level and update the corresponding statistical histogram statistics; Step S2: calculate the mean, standard deviation and kurtosis value corresponding to each group of levels according to the statistical histogram statistics; Step S3: compensate the standard deviation by kurtosis value, calculate the calibrated standard deviation on the level, and calculate Q value according to the mean and calibrated standard deviation; Step S4: calculate the respective corresponding bit error rate according to Q value and take the mean to get the current bit error rate statistics of the optical module.

2. The SNR compensation method in the presence of PAM4 lower MPI interference of claim 1, wherein, In the step S1: PAM4 signal technology uses four different signal levels for signal transmission, and the software collects the sampling data after equalization on each group of PAM levels of PAM4 as needed when there is idle scheduling resource, and each group of PAM level data is stored in the form of statistical histogram statistics; Collect the sampling data after equalization multiple times and update the corresponding statistical histogram statistics until the statistical amount reaches the software threshold.

3. The method of SNR compensation in the presence of PAM4 lower MPI interference of claim 1, wherein, In the step S2: Calculate the mean μ, standard deviation σ and kurtosis value k corresponding to each group of levels according to the statistical histogram statistics: Where i=0, 1, 2, 3, respectively represent the four levels of PAM4 signal; hist is the statistical value of the number of sampling values on each level value in the range of 0-255 levels, and j is the index of hist statistical result.

4. The method of SNR compensation in the presence of PAM4 lower MPI interference of claim 1, wherein, In the step S3: Compensate the standard deviation by kurtosis value, calculate the calibrated standard deviation on the four groups of PAM levels: Calculate Q value according to the mean and calibrated standard deviation, the calculation method is to calculate the open eye distance d according to the mean of adjacent PAM, calculate the noise sigma according to the calibrated standard deviation of adjacent PAM, and the ratio of the two is Q value, three Q values are calculated under PAM4: Where i=0, 1, 2, represent three eyes of PAM4 signal.

5. The method of SNR compensation in the presence of PAM4 lower MPI interference of claim 1, wherein, In the step S4: Calculate the respective corresponding bit error rate ber according to erfc function and take the mean to get the current bit error rate statistics of the optical module: Where the coefficients a, b, c are configured by software, and ber_m is the mean ber calculated by three eyes.

6. A SNR compensation system in the presence of MPI interference for PAM4, characterized by, Comprise: Module M1: collect the sampling data after equalization on the level and update the corresponding statistical histogram statistics; Module M2: calculate the mean, standard deviation and kurtosis value corresponding to each group of levels according to the statistical histogram statistics; Module M3: compensate the standard deviation by kurtosis value, calculate the calibrated standard deviation on the level, and calculate Q value according to the mean and calibrated standard deviation; Module M4: calculate the respective corresponding bit error rate according to Q value and take the mean to get the current bit error rate statistics of the optical module.

7. The SNR compensation system for PAM4 under MPI interference of claim 6, wherein, In the module M1: PAM4 signal technology uses four different signal levels for signal transmission, and the software collects the sampling data after equalization on each group of PAM levels of PAM4 as needed when there is idle scheduling resource, and each group of PAM level data is stored in the form of statistical histogram statistics; Collect the sampling data after equalization multiple times and update the corresponding statistical histogram statistics until the statistical amount reaches the software threshold.

8. The SNR compensation system in the presence of PAM4 lower MPI interference of claim 6, wherein, In the module M2: Calculate the mean μ, standard deviation σ and kurtosis value k corresponding to each group of levels according to the statistical histogram statistics: Wherein, i = 0, 1, 2, 3, respectively represent the 4 groups of levels of PAM4 signal;Hist is the statistical value of the number of sampling values at each level value in the range of 0-255 levels, and j is the index of the statistical result of hist.

9. The SNR compensation system in the presence of PAM4 lower MPI interference of claim 6, wherein, In the module M3: By compensating the standard deviation with the kurtosis value, the calibrated standard deviation of the 4 groups of PAM levels is calculated: According to the mean value and the calibrated standard deviation, the Q value is calculated, and the calculation method is to calculate the opening distance d according to the mean value of the adjacent PAM, to calculate the noise sigma according to the calibrated standard deviation of the adjacent PAM, and the ratio of the two is the Q value, and 3 Q values are calculated under PAM4: Wherein, i = 0, 1, 2, represent the 3 eyes of PAM4 signal.

10. The SNR compensation system in the presence of PAM4 lower MPI interference of claim 6, wherein, In the module M4: 3 Q values are calculated according to the erfc function to obtain the respective bit error rate ber, and the mean value is obtained to obtain the current bit error rate statistical value of the optical module: Wherein, the coefficients a, b, c are configured by software, and ber_m is the mean value ber calculated by the three eyes.

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