Broadband power line carrier communication frequency band detection method and system

Abstract

The invention relates to the technical field of frequency band detection, in particular to a broadband power line carrier communication frequency band detection method and a broadband power line carrier communication frequency band detection system. According to the difference between energy corresponding to each peak value in the modal component and the peak width ratio of each peak value, obtaining a characteristic value of the modal component influenced by interference, and according to the difference between the frequency range of the modal component and the frequency range of energy change, obtaining the interference degree of each modal component, and obtaining a signal adjustment coefficient to adjust a wavelet threshold value; and analyzing the difference between the signal-to-noise ratios of the filtered modal components, reconstructing the modal components, and obtaining the working frequency band of the power line carrier communication signal according to the similarity between the reconstructed signals and the standard signals of the frequency bands corresponding to the modal components in combination with the bit error rate of the frequency bands. According to the invention, more accurate broadband power line carrier communication frequency band detection can be realized.

Description

Technical Field

[0001] The present application relates to the technical field of frequency band detection, and in particular to a method and system for detecting a frequency band in broadband power line carrier communication. Background Art

[0002] Power Line Carrier Communication (PLCC) is widely distributed in homes, businesses and industrial environments. It does not require the laying of additional dedicated communication lines and has the advantages of low cost and easy installation. It can be used in smart home control, data transmission in smart grids, and industrial automation.

[0003] The frequency band in power line carrier communication refers to the frequency range used to transmit carrier signals. Different frequency bands have different transmission characteristics on power lines. Selecting the appropriate frequency band can reduce signal attenuation, distortion and interference, thereby improving the reliability and stability of communication and ensuring the accuracy and integrity of data transmission. By detecting the frequency band of broadband power line carrier communication, the frequency band can be reasonably selected, the limited spectrum resources can be fully utilized, and spectrum conflicts with other communication systems or power equipment can be avoided. The spectrum utilization efficiency can be improved, and multiple communication devices or systems can coexist in the same power network. However, there are various noises in the power line environment, such as electromagnetic noise generated by power equipment and radio frequency interference in the surrounding environment. The intensity and frequency characteristics of these noises vary with time and space, making the noise background in the detected signal complex, increasing the difficulty of accurately detecting the frequency band, and may lead to misjudgment or missed judgment. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of this application is to provide a broadband power line carrier communication frequency band detection method and system, and the technical solutions adopted are as follows: The present application provides a method for detecting a broadband power line carrier communication frequency band, comprising the following steps: Acquire a power line carrier communication signal at a receiving end; Perform modal decomposition on the power line carrier communication signal, and obtain the characteristic value of each modal component affected by interference according to the correlation between each modal component and the power line carrier communication signal, combined with the difference between the energy data corresponding to each peak in each modal component and the peak width ratio of each peak; obtain the frequency range of energy change of each modal component according to the frequency data corresponding to the peak in each modal component, obtain the interference degree of each modal component according to the difference between the frequency range of each modal component and the frequency range of energy change, combined with the characteristic value of each modal component affected by interference, and then obtain the signal adjustment coefficient of each modal component, and adjust the wavelet threshold by the signal adjustment coefficient to filter each modal component; The difference between the signal-to-noise ratios of each modal component after filtering is used to obtain the weight of each modal component during signal reconstruction. The modal components are superimposed to obtain the reconstructed signal. The working frequency band of the power line carrier communication signal is obtained based on the similarity between each reconstructed signal and the standard signal of the frequency band corresponding to each modal component and the bit error rate of each frequency band.

[0005] Preferably, the method for calculating the eigenvalues ​​of the modal components affected by interference is: The frequency domain transformation of each modal component is performed to obtain the spectrum of each modal component, and the peak value in the spectrum is extracted. The calculation formula of the eigenvalue of the modal component affected by the interference is: ;in, Indicates The eigenvalues ​​of the modal components affected by the disturbance; Indicates The correlation between the modal components and the power line carrier communication signal; Indicates The modal component The cumulative result of the absolute value of the difference between the energy data of a peak and the energy data of each other peak; Indicates The modal component The proportion of the peak width data corresponding to a peak in the total of all peak width data; Indicates the number of peaks.

[0006] Preferably, the The correlation between the modal component and the power line carrier communication signal is Pearson correlation coefficient between the modal components and the power line carrier communication signal.

[0007] Preferably, the method for obtaining the frequency range of energy change of each modal component is: obtaining the minimum and maximum values ​​of the frequency data corresponding to all peak values ​​in each modal component, and taking the frequency band between the minimum and maximum values ​​as the frequency range of energy change of each modal component.

[0008] Preferably, the method for obtaining the interference degree of each modal component is: The Jaccard coefficient between the frequency range of each modal component and the frequency range of energy change of each modal component is calculated, and the ratio of the characteristic value of each modal component affected by interference to the Jaccard coefficient is used as the interference degree of each modal component.

[0009] Preferably, the signal adjustment coefficient of each modal component is a normalized result of the interference degree of each modal component.

[0010] Preferably, adjusting the wavelet threshold by using the signal adjustment coefficient specifically includes: The wavelet threshold calculation formula after adjustment of each modal component is: ,in, is the wavelet threshold adjusted for the modal component; is the signal adjustment coefficient of the modal component; is the initial wavelet denoising threshold.

[0011] Preferably, the method for calculating the weights of the modal components during signal reconstruction is: ,in, Indicates The weights of the modal components; and Respectively represent and The processing result of the Softmax function of the signal-to-noise ratio of each modal component; represents the number of modal components.

[0012] Preferably, the method for acquiring the working frequency band of the power line carrier communication signal is: The cosine similarity between the reconstructed signal corresponding to each modal component and the standard signal of the frequency band corresponding to each modal component is calculated, and the bit error rate of the frequency band corresponding to each modal component is counted, and the ratio of the cosine similarity to the bit error rate is calculated, and the frequency band corresponding to the modal component with the largest ratio is used as the working frequency band of the power line carrier communication signal.

[0013] An embodiment of the present application also provides a broadband power line carrier communication frequency band detection system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein when the processor executes the computer program, the steps of any one of the above-mentioned broadband power line carrier communication frequency band detection methods are implemented.

[0014] From the above, it can be seen that the broadband power line carrier communication frequency band detection method and system provided by the present application have at least the following beneficial effects: This application deeply analyzes the interference situation in the broadband power line carrier communication environment, and uses the modal decomposition method to study the signal interference characteristics in different frequency ranges. Taking into full consideration the differences in frequency and energy changes of the received signal after interference, the filtering and noise reduction processing of signal interference in different frequency ranges is optimized and adjusted. Different from the conventional method of processing high-frequency noise of power line carrier signals at this stage, this application performs targeted noise reduction processing based on the interference impact characteristics of different frequency ranges, and realizes the optimization and adjustment of filtering; At the same time, after performing noise reduction processing on signals in different frequency ranges, the present application reconstructs the signals in combination with the signal-to-noise ratio, and on this basis, judges and analyzes different specific frequency bands of the reconstructed signals, thereby accurately determining the working frequency band of the received power line carrier signal, and achieving more accurate broadband power line carrier communication frequency band detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are 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 creative work.

[0016] Figure 1 A flowchart of a broadband power line carrier communication frequency band detection method provided in this application. DETAILED DESCRIPTION

[0017] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following is a detailed description of a broadband power line carrier communication frequency band detection method and system proposed in the present application, its specific implementation method, structure, features and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0018] Unless otherwise specified and limited, terms such as "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a circuit structure, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such articles or devices. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the article or device including the element. In addition, the term "and\or" used herein includes any and all combinations of one or more related listed items. All technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of this application.

[0019] The following is a detailed description of a broadband power line carrier communication frequency band detection method and system provided by the present application in conjunction with the accompanying drawings.

[0020] See also Figure 1, which shows a flowchart of a broadband power line carrier communication frequency band detection method provided by an embodiment of the present application, including the following steps: Step 1: Obtain a power line carrier communication signal at a receiving end.

[0021] In the power line network, in order to achieve efficient and accurate collection of power line carrier communication signals, it is necessary to carefully select suitable professional collection equipment and install it reasonably at the access point or key node position of the power line, such as near the distribution box. These locations can ensure that the collection equipment can obtain stable and complete power line carrier communication signals, and minimize the degradation of signal quality caused by signal transmission loss or external interference.

[0022] For example, Tektronix's MSO58 series digital oscilloscope can be used to meet the requirements for power line carrier communication signal acquisition; the analog-to-digital converter (ADC) can accurately sample MHz-level bandwidth signals, and the sampling rate is usually set at 20MHz and above, which can fully meet the requirements of the Nyquist sampling theorem and ensure accurate restoration of the signal.

[0023] So far, the transmitted power line carrier communication signal is obtained through the above processing.

[0024] Step 2: Perform modal decomposition on the power line carrier communication signal, and obtain the characteristic value of each modal component affected by interference according to the correlation between each modal component and the power line carrier communication signal, combined with the difference between the energy data corresponding to each peak in each modal component and the peak width ratio of each peak; obtain the frequency range of energy change of each modal component according to the frequency data corresponding to the peak in each modal component, and obtain the interference degree of each modal component according to the difference between the frequency range of each modal component and the frequency range of energy change, combined with the characteristic value of each modal component affected by interference, and then obtain the signal adjustment coefficient of each modal component, and adjust the wavelet threshold by the signal adjustment coefficient to filter each modal component.

[0025] In the process of broadband power line carrier communication, due to the complex signal transmission environment, there are interferences from various background signals. These interferences will affect the quality of the power line carrier communication signal transmitted to the output end, interfere with the strength and frequency characteristics of the original transmission signal, make it difficult to accurately analyze the working frequency band characteristics of the broadband power line carrier signal, and easily cause misjudgment in the frequency band characteristic analysis of the carrier communication signal.

[0026] Considering that different frequency bands are affected by noise, interference and signal attenuation to different degrees under complex environmental interference, in this embodiment, the noise reduction processing of the interference effect of communication signals in different frequency bands is optimized and adjusted, aiming to perform precise filtering processing based on the interference effect characteristics of different frequency bands, so as to accurately compare the similarity between the received signal and the standard signal in different frequency bands, thereby accurately judging the working frequency band of the received signal. Specifically, this embodiment includes the following processes: When processing power line carrier communication signals, the power line carrier communication signals obtained by the receiving end are first used as input data, and the variational mode decomposition algorithm is used for processing, so as to obtain the modal components of the power line carrier communication signals corresponding to a specific frequency range. When signals in different frequency ranges are interfered with, their spectrum distribution will show peaks, spectrum broadening and peak shift characteristics, and the correlation between the signal in this frequency range and the original signal will also decrease.

[0027] Based on the above situation, for each modal component after the decomposition of the power line carrier communication signal, the correlation between it and the power line carrier communication signal is calculated by the Pearson correlation coefficient. The smaller the correlation judgment result, the greater the interference effect of the signal in this frequency range compared with the original signal, which in turn has an adverse effect on the judgment of the useful signal.

[0028] In order to further analyze the interference impact characteristics of communication signals in different frequency ranges, the Fourier transform method is used to obtain the spectrum diagram of each modal component. In a complex communication environment, signals in different frequency ranges may have spectrum broadening due to interference. Traditional methods for determining the distribution range of signal spectra in different frequency ranges on the frequency axis, such as threshold-based and bandwidth-defined methods, often ignore the differences in energy anomalies under the influence of actual interference, resulting in large errors in the analysis of spectrum broadening at different frequencies.

[0029] Therefore, this embodiment combines the above analysis, and analyzes the signal interference characteristics at different frequencies by obtaining the distribution range of the signal spectrum of each modal component on the frequency axis. Specifically, the energy data at different frequencies in the spectrum of each modal component is used as input, and the findpeak function in MATLAB is used to obtain the energy data and frequency data corresponding to the peak in the energy data, and the peak width data corresponding to each peak is obtained according to the principle of full width at half maximum (FWHM). The peak width data can reflect the interference influence range at the corresponding frequency. Further, the proportion of the peak width data corresponding to each peak in the sum of all peak width data is calculated. The larger the proportion, the greater the influence of the abnormal energy data in the current frequency range on the judgment of the spectrum broadening distribution range. At the same time, the cumulative result of the absolute value of the difference between the energy data corresponding to each peak and the energy data corresponding to each other peak is calculated, and the mean of the absolute values ​​corresponding to all peaks is counted. The larger the mean, the more significant the peak feature generated by the interference of the frequency corresponding to the current peak is. Based on the above analysis, the characteristic value affected by the interference of each modal component is calculated, and the specific calculation relationship is: in, Indicates The eigenvalues ​​of the modal components affected by the disturbance; Indicates The correlation between the modal components and the power line carrier communication signal; Indicates The modal component The cumulative result of the absolute value of the difference between the energy data of a peak and the energy data of each other peak; Indicates The modal component The proportion of the peak width data corresponding to a peak in the total of all peak width data; Indicates the number of peaks. The larger the calculated eigenvalue of the interference effect, the more significant the frequency and energy change characteristics of the current modal component caused by the interference, which will cause greater interference to the determination of the current signal working frequency band.

[0030] When processing the received power line carrier communication signal, each modal component decomposed is deeply analyzed. For each modal component, the frequency data corresponding to all peaks in the modal component is obtained, the maximum and minimum values ​​are found, and the frequency band between the minimum and maximum values ​​is used as the frequency range of the energy change of the modal component, so as to obtain the frequency range of the energy change of each modal component. Further, the Jaccard coefficient between the frequency range of each modal component and the frequency range of the energy change of each modal component is calculated. The larger the Jaccard coefficient, the greater the possibility of spectrum broadening due to interference, and accordingly, the greater the degree of interference to the information in the corresponding frequency range.

[0031] In order to more accurately determine the degree to which each modal component is affected by interference, for each modal component, the ratio of its eigenvalue affected by interference to the corresponding Jaccard coefficient is calculated as the interference degree of each modal component. The greater the interference degree, the higher the degree of interference in the corresponding frequency range of the modal component of the received signal. The interference degrees corresponding to all modal components are normalized, and the normalized results of the interference degrees of each modal component are used as the signal adjustment coefficients of each modal component. Signal Conditioning Factor The larger the value is, the greater the interference is within the frequency range corresponding to each modal component. Therefore, greater signal filtering adjustment is required to ensure the signal filtering effect.

[0032] In this embodiment, a wavelet denoising algorithm is used to filter the signal, and the filtering process is optimized and adjusted according to the interference influence characteristics in different frequency ranges. Specifically, for each modal component, a wavelet transform is first performed on it, and the wavelet denoising threshold ϑ of each modal component is determined by the VisuShrink algorithm. Then, the wavelet threshold used for filtering and denoising is adjusted using the signal adjustment coefficient corresponding to each modal component, and the adjustment formula is: ,in is the wavelet threshold adjusted for the modal component; is the signal adjustment coefficient of the modal component; is the initial wavelet denoising threshold, obtained by the VisuShrink algorithm.

[0033] It can be understood that the larger the signal adjustment coefficient is, the greater the corresponding interference effect is. In this case, the wavelet threshold is adjusted to a smaller value accordingly, thereby reducing the interference of complex signals on signals within different frequency ranges.

[0034] Step 3: Obtain the weight of each modal component during signal reconstruction by measuring the difference between the signal-to-noise ratios of each modal component after filtering, and obtain the reconstructed signal by superimposing each modal component. According to the similarity between each reconstructed signal and the standard signal of the frequency band corresponding to each modal component, combined with the bit error rate of each frequency band, the working frequency band of the power line carrier communication signal is obtained.

[0035] After decomposing the received power line carrier communication signal into multiple modal components and optimizing the filtering and noise reduction, the power line carrier communication signal in different frequency ranges is reconstructed. The specific reconstruction process is as follows: First, each modal component is subjected to denoising, and its signal-to-noise ratio after denoising is calculated. The signal-to-noise ratio of each modal component is subjected to a Softmax function operation to determine the weight of each modal component in the signal superposition and reconstruction process. Specifically, the formula for determining the weight is: ,in, Indicates The weights of the modal components; and Respectively represent and The processing result of the Softmax function of the signal-to-noise ratio of each modal component; Therefore, in this embodiment, by performing signal reconstruction based on the signal-to-noise ratio, evaluating the signal noise reduction processing effect in different frequency ranges, and then adjusting the weight of signal reconstruction, the influence of interference signals on communication is further weakened.

[0036] Further, after determining the weight of each modal component, the power line carrier communication signal is subjected to superposition processing at different frequencies after noise reduction processing. The detailed process of superposition processing of the signal after variational modal decomposition to obtain the reconstructed signal belongs to the technical content well known to those skilled in the art and will not be elaborated here.

[0037] Since the transmission characteristics of different frequency bands on the power line show significant differences; usually, the low-frequency band signal has a smaller attenuation during the transmission process and can achieve a longer transmission distance, but its bandwidth is relatively narrow; while the high-frequency band signal has a larger bandwidth, but faces the problem of rapid attenuation and limited transmission distance. Therefore, for each frequency band corresponding to each modal component in this embodiment, the power line carrier communication signal at the receiving end is first filtered and denoised by the above method of this embodiment. After the noise reduction process is completed, in this embodiment, the bit error rate (BER) of the frequency band corresponding to each modal component is calculated. The calculation process is a prior art and is not specifically described in this embodiment. Further, the cosine similarity between the reconstructed signal corresponding to each modal component and the standard signal of the frequency band corresponding to each modal component is calculated, and the bit error rate and the cosine similarity are used to detect and determine the working frequency band of the power line carrier communication signal. It should be noted that the standard signal corresponding to each frequency band is selected by itself through the actual application scenario. In the practice of power line carrier communication, different regions have formulated clear specifications for the use of its spectrum, and practitioners need to fully review and strictly follow these standards. Taking power line broadband carrier (HPLC) communication as an example, it clearly defines a series of specific frequency bands, which are not limited to 1.953MHz-11.96MHz and 2.441MHz-5.615MHz.

[0038] In this embodiment, the ratios of the cosine similarity and the bit error rate of the frequency bands corresponding to the modal components are respectively obtained, and the frequency band corresponding to the maximum ratio is used as the working frequency band of the currently received power line carrier communication signal.

[0039] Based on the same inventive concept as the above method, an embodiment of the present application also provides a broadband power line carrier communication frequency band detection system, including a memory, a processor, and a computer program stored in the memory and running on the processor, and when the processor executes the computer program, the steps of any one of the above-mentioned broadband power line carrier communication frequency band detection methods are implemented.

[0040] It is to be understood that the sequence of the embodiments of the present application described above is for description only and does not represent the advantages and disadvantages of the embodiments. The above describes specific embodiments of the present specification. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0041] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0042] The above content is only an implementation method of the present application and is not intended to limit the scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the protection scope of the present application.

Claims

1. A broadband power line carrier communication frequency band detection method, characterized in that: The following steps are involved: Acquire a power line carrier communication signal at a receiving end; Perform modal decomposition on the power line carrier communication signal, and obtain the characteristic value of each modal component affected by interference based on the correlation between each modal component and the power line carrier communication signal, combined with the difference between the energy data corresponding to each peak in each modal component and the peak width ratio of each peak; The frequency range of energy change of each modal component is obtained according to the frequency data corresponding to the peak value in each modal component. The interference degree of each modal component is obtained according to the difference between the frequency range of each modal component and the frequency range of energy change, combined with the characteristic value of each modal component affected by interference, and then the signal adjustment coefficient of each modal component is obtained. The wavelet threshold is adjusted by the signal adjustment coefficient to filter each modal component. The difference between the signal-to-noise ratios of each modal component after filtering is used to obtain the weight of each modal component during signal reconstruction. The modal components are superimposed to obtain the reconstructed signal. The working frequency band of the power line carrier communication signal is obtained based on the similarity between each reconstructed signal and the standard signal of the frequency band corresponding to each modal component and the bit error rate of each frequency band.

2. A broadband power line carrier communication frequency band detection method as claimed in claim 1, characterized in that: The calculation method of the eigenvalues ​​of the modal components affected by interference is: The frequency domain transformation of each modal component is performed to obtain the spectrum of each modal component, and the peak value in the spectrum is extracted. The calculation formula of the eigenvalue of the modal component affected by the interference is: ;in, Indicates The eigenvalues ​​of the modal components affected by the disturbance; Indicates The correlation between the modal components and the power line carrier communication signal; Indicates The modal component The cumulative result of the absolute value of the difference between the energy data of a peak and the energy data of each other peak; Indicates The modal component The proportion of the peak width data corresponding to a peak in the total of all peak width data; Indicates the number of peaks.

3. A broadband power line carrier communication frequency band detection method as claimed in claim 2, characterized in that: The said The correlation between the modal component and the power line carrier communication signal is Pearson correlation coefficient between the modal components and the power line carrier communication signal.

4. A broadband power line carrier communication frequency band detection method as claimed in claim 1, characterized in that: The method for obtaining the frequency range of energy change of each modal component is: obtaining the minimum and maximum values ​​of the frequency data corresponding to all peak values ​​in each modal component, and taking the frequency band between the minimum and maximum values ​​as the frequency range of energy change of each modal component.

5. A broadband power line carrier communication frequency band detection method as claimed in claim 1, characterized in that: The method for obtaining the interference degree of each modal component is: The Jaccard coefficient between the frequency range of each modal component and the frequency range of energy change of each modal component is calculated, and the ratio of the characteristic value of each modal component affected by interference to the Jaccard coefficient is used as the interference degree of each modal component.

6. A broadband power line carrier communication frequency band detection method as claimed in claim 1, characterized in that: The signal adjustment coefficient of each modal component is a normalized result of the interference degree of each modal component.

7. A broadband power line carrier communication frequency band detection method as claimed in claim 1, characterized in that: The step of adjusting the wavelet threshold by using the signal adjustment coefficient specifically includes: The wavelet threshold calculation formula after adjustment of each modal component is: ,in, is the wavelet threshold adjusted for the modal component; is the signal adjustment coefficient of the modal component; is the initial wavelet denoising threshold.

8. A broadband power line carrier communication frequency band detection method as claimed in claim 1, characterized in that: The calculation method of the weight of each modal component during signal reconstruction is: ,in, Indicates The weights of the modal components; and Respectively represent and The processing result of the Softmax function of the signal-to-noise ratio of each modal component; represents the number of modal components.

9. A broadband power line carrier communication frequency band detection method as claimed in claim 1, characterized in that: The method for obtaining the working frequency band of the power line carrier communication signal is: The cosine similarity between the reconstructed signal corresponding to each modal component and the standard signal of the frequency band corresponding to each modal component is calculated, and the bit error rate of the frequency band corresponding to each modal component is counted, and the ratio of the cosine similarity to the bit error rate is calculated, and the frequency band corresponding to the modal component with the largest ratio is used as the working frequency band of the power line carrier communication signal.

10. A broadband power line carrier communication frequency band detection system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of a broadband power line carrier communication frequency band detection method as described in any one of claims 1-9 are implemented.

Images