A broadband power line carrier communication frequency band detection method and system

Abstract

This application relates to the field of frequency band detection technology, and particularly relates to a broadband power line carrier communication frequency band detection method and system. The method includes: acquiring a power line carrier communication signal and performing modal decomposition, obtaining an eigenvalue of the modal component affected by interference according to the correlation between each modal component and the signal, combining the difference between the energies corresponding to each peak in the modal component and the peak width ratio of each peak, and obtaining the interference degree of each modal component by combining the difference between the frequency range of the modal component and the frequency range of the energy change, obtaining a signal adjustment coefficient to adjust the wavelet threshold; analyzing the difference between the signal-to-noise ratios of each modal component after filtering, reconstructing each modal component, and obtaining the working frequency band of the power line carrier communication signal according to the similarity between each reconstructed signal and the standard signal corresponding to the frequency band of each modal component, in combination with the bit error rate of each frequency band. This application can achieve more accurate broadband power line carrier communication frequency band detection.

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 used in homes, businesses, and industrial environments. It eliminates the need for dedicated communication lines and offers advantages such as 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 the carrier signal. Different frequency bands have different transmission characteristics on power lines. Selecting the appropriate frequency band can reduce signal attenuation, distortion, and interference, thereby improving communication reliability and stability and ensuring the accuracy and integrity of data transmission. Frequency band detection for broadband power line carrier communication can help rationally select frequency bands, fully utilize limited spectrum resources, avoid spectrum conflicts with other communication systems or power equipment, improve spectrum efficiency, and enable the coexistence of multiple communication devices or systems on the same power network. However, various noises exist in the power line environment, such as electromagnetic noise generated by power equipment and radio frequency interference from the surrounding environment. The intensity and frequency characteristics of this noise vary over time and space, resulting in a complex noise background in the detected signal, increasing the difficulty of accurately detecting the frequency band and potentially leading to misjudgments or missed detections. 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, the technical solutions adopted are as follows:

[0005] The present invention provides a method for detecting a broadband power line carrier communication frequency band, comprising the following steps:

[0006] Obtaining a power line carrier communication signal at a receiving end;

[0007] Perform modal decomposition on the power line carrier communication signal. According to the correlation between each modal component and the power line carrier communication signal, combined with the differences between the energy data corresponding to each peak in each modal component and the proportion of the peak width of each peak, obtain the eigenvalue of each modal component affected by interference; obtain the frequency range of the energy change of each modal component according to the frequency data corresponding to the peak in each modal component, and according to the difference between the frequency range of each modal component and the frequency range of the energy change, combined with the eigenvalue of each modal component affected by interference, obtain the interference degree of each modal component, and then obtain the signal adjustment coefficient of each modal component. Adjust the wavelet threshold through the signal adjustment coefficient to perform filtering processing on each modal component;

[0008] Through the differences between the signal-to-noise ratios of each modal component after filtering processing, obtain the weights of each modal component during signal reconstruction. Perform superposition processing on each modal component to obtain the reconstructed signal. According to the similarity between each reconstructed signal and the standard signal in the corresponding frequency band of each modal component, combined with the bit error rate of each frequency band, obtain the working frequency band of the power line carrier communication signal.

[0009] Preferably, the calculation method of the eigenvalue of each modal component affected by interference is as follows:

[0010] Perform frequency domain transformation on each modal component to obtain the spectrogram of each modal component, extract the peaks in the spectrogram, and the calculation formula of the eigenvalue of the modal component affected by interference is:

[0011] ; where represents the eigenvalue of the th modal component affected by interference; represents the correlation between the th modal component and the power line carrier communication signal; represents the cumulative result of taking the absolute value of the difference between the energy data of the th peak of the th modal component and the energy data of each other peak; represents the proportion of the peak width data corresponding to the th peak of the th modal component in the total sum of all peak width data; represents the number of peaks.

[0012] Preferably, the correlation between the th modal component and the power line carrier communication signal is the Pearson correlation coefficient between the th modal component and the power line carrier communication signal.

[0013] Preferably, the method for obtaining the frequency range of the energy change of each modal component is as follows: Obtain the minimum value and the maximum value of the frequency data corresponding to all the peaks in each modal component, and use the frequency band between the minimum value and the maximum value as the frequency range of the energy change of each modal component.

[0014] Preferably, the method for obtaining the interference degree of each modal component is as follows:

[0015] Calculate the Jaccard coefficient between the frequency range of each modal component and the frequency range of the energy change of each modal component, and use the ratio of the eigenvalue affected by interference of each modal component to the Jaccard coefficient as the interference degree of each modal component.

[0016] Preferably, the signal adjustment coefficient of each modal component is the normalization result of the interference degree of each modal component.

[0017] Preferably, the adjustment of the wavelet threshold by the signal adjustment coefficient specifically includes:

[0018] The calculation formula for the wavelet threshold after adjustment of each modal component is: , where is the wavelet threshold after adjustment of the modal component; is the signal adjustment coefficient of the modal component; is the initial wavelet denoising threshold.

[0019] Preferably, the calculation method for the weight of each modal component during signal reconstruction is:

[0020] , where represents the weight of the th modal component; and respectively represent the processing results of the Softmax function of the signal-to-noise ratios of the th and the th modal components; represents the number of modal components.

[0021] Preferably, the method for obtaining the working frequency band of the power line carrier communication signal is:

[0022] Calculate the cosine similarity between the reconstructed signal corresponding to each modal component and the standard signal in the corresponding frequency band of each modal component, and count the bit error rate in the corresponding frequency band of each modal component. Calculate the ratio of the cosine similarity to the bit error rate, and use the frequency band of the modal component corresponding to the largest ratio as the working frequency band of the power line carrier communication signal.

[0023] 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. 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.

[0024] As can be seen from the above, the broadband power line carrier communication frequency band detection method and system provided by this application have at least the following beneficial effects:

[0025] 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 are 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, realizing the optimization and adjustment of filtering;

[0026] At the same time, after performing noise reduction processing on signals in different frequency ranges, this application reconstructs the signals in combination with the signal-to-noise ratio, and on this basis, judges and analyzes the reconstructed signals in different specific frequency bands, thereby accurately determining the working frequency band of the received power line carrier signal, and realizing more accurate broadband power line carrier communication frequency band detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present application or 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.

[0028] Figure 1 This is a flowchart of a broadband power line carrier communication frequency band detection method provided in this application. DETAILED DESCRIPTION

[0029] In order to further illustrate the technical means and effects adopted by this application to achieve the predetermined invention objectives, the following, in conjunction with the accompanying drawings and preferred embodiments, describes in detail a broadband power line carrier communication frequency band detection method and system proposed in this application, its specific implementation, structure, features and effects. 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 of one or more embodiments may be combined in any suitable form.

[0030] Unless otherwise specified or limited, terms such as "including", "comprising" or any other variant 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 other elements not expressly listed, or elements inherent to such article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the presence of additional identical elements in the article or device including the element. In addition, the term "and / or" as used herein includes any and all combinations of one or more of the related listed items. All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs.

[0031] The following specifically describes the specific solutions of a broadband power line carrier communication frequency band detection method and system provided by this application in conjunction with the accompanying drawings.

[0032] Please refer to Figure 1 , which shows a flowchart of the steps of a broadband power line carrier communication frequency band detection method provided by an embodiment of this application, including the following steps:

[0033] Step 1, obtain the power line carrier communication signal at the receiving end.

[0034] In the power line network, to achieve efficient and accurate acquisition of power line carrier communication signals, it is necessary to carefully select suitable professional acquisition equipment and reasonably install it at the access point or key node position of the power line, such as near the distribution box. These positions can ensure that the acquisition equipment obtains stable and complete power line carrier communication signals, and to the greatest extent avoid signal quality degradation caused by signal transmission loss or external interference.

[0035] For example, the MSO58 series digital oscilloscopes of Tektronix can be selected, which can meet the requirements for power line carrier communication signal acquisition; among them, the analog-to-digital converter (ADC) can accurately sample MHz-level bandwidth signals, and the sampling rate is usually set at 20 MHz or above, which can fully meet the requirements of the Nyquist sampling theorem and ensure accurate signal restoration.

[0036] So far, the transmitted power line carrier communication signal has been obtained through the above processing.

[0037] Step 2: Perform modal decomposition on the power line carrier communication signal. Based on the correlation between each modal component and the power line carrier communication signal, and combining the differences between the energy data corresponding to each peak in each modal component and the peak width ratios of each peak, obtain the characteristic values of each modal component affected by interference. According to the frequency data corresponding to the peaks in each modal component, obtain the frequency range of the energy change of each modal component. Based on the differences between the frequency range of each modal component and the frequency range of the energy change, and combining the characteristic values of each modal component affected by interference, obtain the interference degree of each modal component, and then obtain the signal adjustment coefficient of each modal component. Adjust the wavelet threshold through the signal adjustment coefficient to filter each modal component.

[0038] In the process of broadband power line carrier communication, due to the complex signal transmission environment, there are various background signal interferences. These interferences will affect the quality of the power line carrier communication signal transmitted to the output end, interfere with the intensity and frequency characteristics of the original transmission signal, making it difficult to accurately analyze the working frequency band characteristics of the broadband power line carrier signal, and thus prone to misjudgment in the analysis of the frequency band characteristics of the carrier communication signal.

[0039] Considering that under the interference of a complex environment, the influence degrees of different frequency bands by noise, interference, and signal attenuation are different. Therefore, in this embodiment, the noise reduction processing of the interference influence on the communication signals of different frequency bands is optimized and adjusted, aiming to perform precise filtering processing based on the interference influence characteristics of different frequency bands, so as to accurately compare the similarity between the received signal and the standard signal in different frequency bands, and thus accurately judge the working frequency band of the received signal. Specifically, the following process is included in this embodiment:

[0040] When processing the power line carrier communication signal, first use the power line carrier communication signal obtained at the receiving end as input data and perform processing using the variational mode decomposition algorithm to obtain the modal components of the power line carrier communication signal corresponding to a specific frequency range. When signals in different frequency ranges are interfered, their spectral distributions will show characteristics such as sharp peaks, spectral broadening, and peak shifts, and at the same time, the correlation between the signals in this frequency range and the original signal will also decrease.

[0041] Based on the above situation, for each modal component after the decomposition of the power line carrier communication signal, calculate its correlation with the power line carrier communication signal through the Pearson correlation coefficient. The smaller the correlation judgment result, the greater the interference influence on the signal in this frequency range compared to the original signal, and thus it has an adverse effect on the judgment of the useful signal.

[0042] To further analyze the interference impact characteristics of communication signals in different frequency ranges, the Fourier transform method is used to obtain the spectrogram of each modal component. In a complex communication environment, signals in different frequency ranges may exhibit spectral broadening due to interference. Traditional methods for determining the distribution range of signal spectra in different frequency ranges on the frequency axis, such as those based on thresholds and bandwidth definitions, often ignore the differences in energy anomalies under actual interference effects, resulting in large analysis errors for spectral broadening at different frequencies.

[0043] Therefore, in combination with the above analysis, in this embodiment, by obtaining the distribution range of the signal spectrum of each modal component on the frequency axis, the signal interference characteristics at different frequencies are analyzed. Specifically, taking the energy data at different frequencies in the spectrum of each modal component as input, the findpeak function in MATLAB is used to obtain the energy data and frequency data corresponding to the peaks in the energy data, and based on the principle of the full width at half maximum (FWHM), the peak width data corresponding to each peak is obtained. This peak width data can reflect the interference impact range at the corresponding frequency. Further, calculate the proportion of the peak width data corresponding to each peak in the total sum of all peak width data. The larger the proportion, the greater the impact of the energy data anomaly in the current frequency range on the judgment of the spectral broadening distribution range. At the same time, calculate the cumulative result of taking the absolute value of the difference between the energy data corresponding to each peak and the energy data corresponding to each other peak, and calculate the average value of all the absolute values corresponding to the peaks. The larger the average value, the more significant the spike feature generated by the interference impact at the frequency corresponding to the current peak. Based on the above analysis, calculate the eigenvalue of the interference impact for each modal component, and its specific calculation formula is:

[0044]

[0045] Where, represents the eigenvalue of the interference impact on the th modal component; represents the correlation between the th modal component and the power line carrier communication signal; represents the cumulative result of taking the absolute value of the difference between the energy data of the th peak of the th modal component and the energy data of each other peak; represents the proportion of the peak width data corresponding to the th peak of the th modal component in the total sum of all peak width data; represents the number of peaks. The larger the calculated eigenvalue of the interference impact, the more significant the frequency and energy change characteristics of the current modal component caused by interference, and the greater the interference on the determination of the current signal working frequency band.

[0046] When processing the received power line carrier communication signal, each modal component obtained by its decomposition is analyzed in depth. For each modal component, the frequency data corresponding to all peaks in the modal component is obtained, the maximum value and the minimum value are found, and the frequency band between the minimum value and the maximum value 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 caused by interference, and correspondingly, the greater the degree of interference on the information in the corresponding frequency range.

[0047] In order to more accurately judge the degree of interference on each modal component, for each modal component, the ratio of the eigenvalue of the interference on it 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 on 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 adjustment coefficient The larger the signal adjustment coefficient, the greater the interference in the frequency range corresponding to each modal component. Therefore, the greater the intensity of signal filtering adjustment is required to ensure the signal filtering effect.

[0048] In this embodiment, the wavelet denoising algorithm is used to filter the signal, and the filtering process is optimized and adjusted according to the interference characteristics in different frequency ranges. Specifically, for each modal component, first perform wavelet transform on it, and determine the wavelet denoising threshold ϑ of each modal component through the VisuShrink algorithm. Then, use the signal adjustment coefficient corresponding to each modal component to adjust the wavelet threshold for filtering and noise reduction. The adjustment formula is: , where is the adjusted wavelet threshold of the modal component; is the signal adjustment coefficient of the modal component; is the initial wavelet denoising threshold, which is obtained through the VisuShrink algorithm.

[0049] It can be understood that the larger the signal adjustment coefficient, the greater the corresponding interference. At this time, the wavelet threshold is adjusted to a smaller value accordingly, so as to reduce the interference of complex signals on the signals in different frequency ranges.

[0050] Step 3: Obtain the weights of each modal component during signal reconstruction based on the differences in the signal-to-noise ratios of each modal component after filtering processing. Perform superposition processing on each modal component to obtain the reconstructed signal. Based on the similarity between each reconstructed signal and the standard signal in the corresponding frequency band of each modal component, and combined with the bit error rate of each frequency band, obtain the working frequency band of the power line carrier communication signal.

[0051] After decomposing the received power line carrier communication signal into multiple modal components and performing optimized adjustment of filtering and noise reduction, signal reconstruction is performed for power line carrier communication signals in different frequency ranges. The specific reconstruction process is as follows:

[0052] First, perform noise reduction processing on each modal component, calculate its signal-to-noise ratio after noise reduction, and perform the Softmax function operation on the signal-to-noise ratio of each modal component to determine the weight of each modal component in the signal superposition and reconstruction process. Specifically, the formula for determining the weight is: , where represents the weight of the th modal component; and respectively represent the processing results of the Softmax function of the signal-to-noise ratios of the th and the th modal components; represents the number of modal components. 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.

[0053] Furthermore, after determining the weights of each modal component, perform superposition processing on the signals of the power line carrier communication signal after noise reduction processing at different frequencies. The detailed process of performing signal superposition processing after variational mode decomposition to obtain the reconstructed signal belongs to the technical content well-known to those skilled in the art and will not be elaborated in detail here.

[0054] Since the transmission characteristics of different frequency bands on power lines show significant differences; generally, low-frequency band signals have a relatively small attenuation degree during transmission and can achieve a relatively long transmission distance, but their bandwidth is relatively narrow; while high-frequency band signals have a large bandwidth but face the problems of rapid attenuation and limited transmission distance. Therefore, for each frequency band corresponding to each modal component in this embodiment, first, the power line carrier communication signal at the receiving end is filtered and denoised by the method described above in this embodiment. After the denoising process, in this embodiment, the bit error rate (BER) of each frequency band corresponding to each modal component is calculated, and the calculation process is prior art and will not be specifically described in this embodiment. Further, the cosine similarity between the reconstructed signal corresponding to each modal component and the standard signal of each frequency band corresponding to each modal component is calculated, and the working frequency band of the power line carrier communication signal is detected and determined based on the bit error rate and the cosine similarity. It should be noted that the standard signals corresponding to each frequency band are selected according to the actual application scenario. In the practice of power line carrier communication, clear specifications have been formulated for the spectrum usage in different regions, and practitioners need to consult and strictly follow these standards comprehensively. Taking power line broadband carrier (HPLC) communication as an example, it clearly defines a series of specific frequency bands, and the frequency bands are not limited to 1.953 MHz - 11.96 MHz and 2.441 MHz - 5.615 MHz.

[0055] In this embodiment, the ratios of the cosine similarity to the bit error rate of each frequency band corresponding to each modal component are respectively obtained, and the frequency band corresponding to the largest ratio is used as the working frequency band of the currently received power line carrier communication signal.

[0056] 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. When the processor executes the computer program, the steps of any one of the above-described broadband power line carrier communication frequency band detection methods are implemented.

[0057] It can be understood that: the above sequence of embodiments of the present application is only for description and does not represent the superiority or inferiority of the embodiments. And the above specifically describes certain embodiments of this specification. Additionally, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0058] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0059] The above content is only an implementation mode of this application and is not intended to limit the scope of this application. Any equivalent structural or equivalent process transformation made by using the content of the specification and drawings of this application, or any direct or indirect application in other related technical fields, shall be similarly included in the protection scope of this application.

Claims

1. A broadband power line carrier communication frequency band detection method, characterized in that Including the following steps: Obtain the power line carrier communication signal of the receiving end; Perform modal decomposition on the power line carrier communication signal, perform frequency domain transformation on each modal component to obtain the spectrogram of each modal component, extract the peaks in the spectrogram, and calculate the eigenvalue of the modal component affected by interference. The calculation formula is: ; where represents the eigenvalue of the th modal component affected by interference; represents the Pearson correlation coefficient between the th modal component and the power line carrier communication signal; represents the cumulative result of taking the absolute value of the difference between the energy data of the th peak of the th modal component and the energy data of each other peak; represents the proportion of the peak width data corresponding to the th peak of the th modal component in the total sum of all peak width data; represents the number of peaks; obtain the frequency range of the energy change of each modal component according to the frequency data corresponding to the peaks in each modal component, and based on the difference between the frequency range of each modal component and the frequency range of the energy change, combined with the eigenvalue of the modal component affected by interference, obtain the interference degree of each modal component, and then obtain the signal adjustment coefficient of each modal component. Adjust the wavelet threshold through the signal adjustment coefficient to perform filtering processing on each modal component; Calculate the weights of each modal component during signal reconstruction. The calculation formula is as follows: , where represents the weight of the -th modal component; and respectively represent the processing results of the Softmax function of the signal-to-noise ratios of the -th and the -th modal components; represents the number of modal components. Perform superposition processing on each modal component to obtain the reconstructed signal. Based on the similarity between each reconstructed signal and the standard signal in the corresponding frequency band of each modal component, combined with the bit error rate of each frequency band, obtain the working frequency band of the power line carrier communication signal.

2. The broadband power line carrier communication frequency band detection method according to claim 1, characterized in that The method for obtaining the frequency range of the energy change of each modal component is: obtain the minimum value and the maximum value of the frequency data corresponding to all the peaks in each modal component, and use the frequency band between the minimum value and the maximum value as the frequency range of the energy change of each modal component.

3. The broadband power line carrier communication frequency band detection method according to claim 1, characterized in that The method for obtaining the interference degree of each modal component is: Calculate the Jaccard coefficient between the frequency range of each modal component and the frequency range of the energy change of each modal component, and use the ratio of the eigenvalue affected by interference of each modal component to the Jaccard coefficient as the interference degree of each modal component.

4. The broadband power line carrier communication frequency band detection method according to claim 1, characterized in that The signal adjustment coefficient of each modal component is the normalization result of the interference degree of each modal component.

5. The broadband power line carrier communication frequency band detection method according to claim 1, characterized in that, Adjusting the wavelet threshold through the signal adjustment coefficient specifically includes: The calculation formula for the wavelet threshold after adjusting each modal component is as follows: , where is the wavelet threshold after adjusting the modal component; is the signal adjustment coefficient of the modal component; is the initial wavelet denoising threshold.

6. The broadband power line carrier communication frequency band detection method according to claim 1, characterized in that, The method for obtaining the working frequency band of the power line carrier communication signal is: Calculate the cosine similarity between the reconstructed signal corresponding to each modal component and the standard signal in the corresponding frequency band of each modal component, and count the bit error rate in the corresponding frequency band of each modal component. Calculate the ratio of the cosine similarity to the bit error rate, and use the frequency band of the modal component corresponding to the largest ratio as the working frequency band of the power line carrier communication signal.

7. 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, it implements the steps of a broadband power line carrier communication frequency band detection method according to any one of claims 1-6.

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