A SEM measurement method for 5G NR signals

Abstract

The application discloses a SEM measurement method for 5G NR signals and belongs to the field of communication system measurement, and comprises the following steps: power values of input signals are calculated by using a full FFT mode; the spectrum of the signals is acquired by using a segmented FFT mode, sudden change points of the spectrum of the signals are filtered out, and test results of each frequency range are optimized; the spectrum measurement of each frequency range is realized by using a multiple iteration-multiple calculation mode, user segmented configuration information is read and traversed, and the spurious of each spectrum is calculated; and parameters of each frequency range are configured by using an xml file reading mode. The method of the application adopts a segmented FFT and segmented windowing combined mode, can not only filter out the sudden change points of the spectrum, prevent the spectrum from being disordered, but also improve the measurement speed and precision, and can meet the test requirements of precision instruments.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of communication system measurement, and particularly relates to a SEM measurement method for 5G NR signals. BACKGROUND

[0002] With the development of science and technology and the improvement of people's living standards, mobile communication has become one of the focuses of people's daily attention. 5G network communication is a relatively advanced network communication technology at present. Compared with the widely used 4G network communication technology, 5G has a very obvious advantage in transmission speed. In the future, 5G will penetrate into various industries and greatly change people's living habits. In the future, 5G technology will accelerate the integration of industries and trigger new changes in the industry. In order to meet the needs of users' complex business, NR (New Radio) uses flexible frame structure and subcarrier configuration, and the architecture is complex, which brings challenges to the test of NR signals. One of the difficulties that need to be broken through is to effectively manage power to prevent signals from being disturbed by external factors.

[0003] In 5G digital communication, energy leakage and nonlinear distortion in the channel can affect the transmission of signals and thus affect the performance of the communication system. SEM (Spectrum Emission Mask) can test the signal spectrum spurious energy and verify whether the working performance of the system transmitter meets the specified limit. Efficient and accurate implementation of SEM testing can be challenging for testers.

[0004] At present, the SEM test method mostly adopts one-key SEM measurement method. According to the protocol, the configuration information is set in advance, and the segmented information of different bandwidth configurations is constantly updated. When the user tests, the user can simply select the waveform file and bandwidth information to output the SEM test result. In addition, the test signal can be generated by a Rohde signal source, and then transmitted to a signal analyzer through LAN or GPIB. The SEM performance is measured by using a scanning spectrum analyzer. This method is simple and fast, but it depends on the measuring instrument and the test environment is limited. Later, scholars introduced a resolution bandwidth filter to reduce the resolution bandwidth in order to improve the measurement accuracy. The increase in scanning time reduces the scanning speed, thereby optimizing the measurement result while reducing the measurement speed. With further research, researchers have also proposed a noise correction algorithm to suppress noise and reduce the impact of noise on signals, thereby improving SEM measurement.

[0005] In summary, these measurement methods are simple and easy to use, but the accuracy is not high or the test environment is limited. How to improve an efficient and accurate SEM measurement method to meet the test requirements of precision instruments has become a technical problem to be solved. SUMMARY

[0006] In view of the above technical problems existing in the prior art, the present application provides a SEM measurement method for 5G NR signals, which is reasonable in design, overcomes the shortcomings of the prior art, and has good effects.

[0007] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] A SEM measurement method for 5G NR signals, comprising the following steps:

[0009] Step 1: using a full FFT method, the power value of the input signal is calculated;

[0010] Step 2: using a segmented FFT method, the spectrum of the signal is obtained, the mutation points of the signal spectrum are filtered out, and the test results of each frequency range are optimized;

[0011] Step 3: using a multiple iteration-multiple calculation method, the spectrum measurement of each frequency range is realized, the user segmented configuration information is read and traversed, and the spurious of each spectrum is calculated;

[0012] Step 4: using the method of reading an xml file, the parameters of each frequency range are configured.

[0013] Preferably, in step 1, the following steps are specifically included:

[0014] Step S11: reading a signal waveform file, simultaneously calculating the IQ data length of the waveform file, and after performing a Fourier transform on the length of data, obtaining the complete frequency domain information of the signal;

[0015] Step S12: using a spectrum shifting method, shifting the frequency spectrum of the signal without distortion to the frequency of the carrier signal;

[0016] Step S13: after spectrum shifting, the frequency domain information of the entire segment of IQ data can be obtained, and then according to the sampling rate, the signal bandwidth and the number of Fourier transform points, the position of the signal in the entire data, i.e. the starting position and the ending position, is calculated, and the frequency domain values of all points in the interval are counted, i.e. the absolute power value of the signal can be obtained.

[0017] Preferably, in step 2, the following steps are specifically included:

[0018] Step S21: dividing the original signal data into several segments according to the number of Fourier transform points, and using the method of windowing or filter for each segment to filter out the jump points of the spectrum, preventing the spectrum from being disorderly, and making the spectrum smoother;

[0019] Step S22: performing Fourier transform on each segment of original data with windowing or filter to obtain the frequency domain information of the original data, and performing spectrum shifting;

[0020] Step S23: after obtaining the frequency domain information of each segment of original data, the power value of each segment of signal is counted and power superposition is carried out, and the superposed power value is divided by the number of segments, that is, the power-averaged frequency spectrum is obtained, since FFT is a linear operation, the final frequency spectrum contains the spectral characteristics of each segment;

[0021] Step S24: according to the sampling rate, the number of Fourier transform points, the resolution bandwidth and the parameter configuration information of each segment, the interval position, that is, the starting position and the ending position, of each frequency segment in the power-averaged spectrum is calculated, and the maximum power value in the interval is calculated, which is the SEM test result in the frequency range.

[0022] Preferably, in step 3, the following steps are specifically included:

[0023] Step S31: according to the 3GPP protocol, the segment configuration information of different bandwidths is calculated, including the starting position, the ending position, the resolution bandwidth and the starting and ending positions of the limit line of each segment; the measurement range corresponding to the bandwidth is calculated by counting all the segment information; if the spectrum of the frequency domain signal exceeds the measurement range, the two-edge truncation method is adopted to discard the excessive number of points, so that the measurement range is located in the middle position of the spectrum;

[0024] Step S32: the measurement result of each segment is calculated in turn in the left-to-right manner, the measurement result includes the maximum power absolute value, the maximum power relative value, the frequency point corresponding to the maximum power and the difference between the maximum power and the limit line, and the overall SEM measurement result of the signal is obtained after traversing all the segments.

[0025] Preferably, in step 4, the following steps are specifically included:

[0026] Step S41: according to the 3GPP protocol, the segment configuration information of different modes and different bandwidths is counted, and the configuration information includes the starting position, the ending position, the resolution bandwidth, the filter type, the scanning time and the starting and ending positions of the limit line of each segment;

[0027] Step S42: the configuration information is written into the xml configuration file according to the differences of modes and bandwidths.

[0028] The beneficial technical effects brought by the present application are as follows:

[0029] The method of the present application adopts the combination of segmented FFT and segmented windowing, which not only can filter out the jump points of the spectrum and prevent the spectrum from being messy, but also improves the measurement speed and accuracy, and can meet the test requirements of precision instruments. In addition, the present method can write the configuration information into the xml configuration file according to the differences of modes and bandwidths, and the user can complete one-key configuration by selecting the xml file corresponding to the mode and bandwidth during testing, which is simple and efficient and convenient for user operation. Attached Figure Description

[0030] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0032] like Figure 1 As shown, a SEM measurement method for 5G NR signals includes the following steps:

[0033] Step 1: To reduce the impact of noise on power, a full FFT method is used to calculate the power value of the input signal; specifically, the following steps are included:

[0034] Step S11: Read the signal waveform file and calculate the IQ data length of the waveform file. Perform a Fourier transform on the data of this length to obtain the complete frequency domain information of the signal. In order to maintain the spectrum information of the original signal, this invention does not introduce a window function or filter when calculating the absolute power value of the signal. Experiments have shown that both will affect the absolute power value of the signal.

[0035] Step S12: Using spectrum shifting, the signal spectrum is shifted to the vicinity of the carrier signal frequency without distortion; this improves signal transmission efficiency and enhances the signal's anti-interference capability.

[0036] Step S13: After spectrum shifting, the frequency domain information of the entire IQ data segment can be obtained. Then, based on the sampling rate, signal bandwidth, and the number of points in the Fourier transform, the position of the signal in the entire data segment, i.e., the start position and the end position, is calculated. The frequency domain values ​​of all points in the interval are counted to obtain the absolute power value of the signal.

[0037] Step 2: Use a segmented FFT method to obtain the signal spectrum, filter out abrupt changes in the signal spectrum, and optimize the test results for each frequency range; specifically, this includes the following steps:

[0038] Step S21: Divide the original signal data into several segments according to the number of Fourier transform points, and use windowing or filtering on each segment to filter out the jump points in the spectrum, so as to prevent the spectrum from becoming cluttered and make the spectrum smoother.

[0039] Step S22: Perform Fourier transform on each segment of the original data with windowing or filtering to obtain the frequency domain information of the original data, and perform spectrum shifting to improve the signal's anti-interference capability;

[0040] Step S23: After obtaining the frequency domain information of each segment of original data, the power value of each segment of signal is counted and power superposition is performed, and the superposed power value is divided by the number of segments, that is, the power-averaged frequency spectrum is obtained. Since FFT is a linear operation, the final frequency spectrum contains the spectral characteristics of each segment;

[0041] Step S24: According to the sampling rate, the number of Fourier transform points, the resolution bandwidth, and the parameter configuration information of each segment, the interval position, that is, the start position and the end position, of each frequency segment in the power-averaged spectrum is calculated, and the maximum power value in the interval is calculated. The value is the SEM test result in the frequency range.

[0042] Step 3: A multiple iteration-multiple calculation method is used to realize the spectrum measurement of each frequency range. The user segmentation configuration information is read and the spurious of each segment spectrum is calculated. Specifically, the following steps are included:

[0043] Step S31: According to the 3GPP protocol, the segmentation configuration information of different bandwidths is calculated, including the start position, the end position, the resolution bandwidth, and the start and end positions of the limit line of each segment. The measurement range corresponding to the bandwidth is calculated by counting all the segmentation information. If the spectrum of the frequency domain signal exceeds the measurement range, the two ends are truncated, and the excess number of points is discarded, so that the measurement range is located in the middle of the spectrum.

[0044] Step S32: The measurement result of each segment is calculated in turn in the left-to-right manner. The measurement result includes the maximum power absolute value, the maximum power relative value, the frequency point corresponding to the maximum power, and the difference between the maximum power and the limit line. After iterating through all the segments, the overall SEM measurement result of the signal is obtained.

[0045] Step 4: The parameters of each frequency range are configured by reading the xml file. Specifically, the following steps are included:

[0046] Step S41: According to the 3GPP protocol, the segmentation configuration information of different modes and different bandwidths is counted. The configuration information includes the start position, the end position, the resolution bandwidth, the filter type, the scanning time, and the start and end positions of the limit line of each segment.

[0047] Step S42: The configuration information is written into the xml configuration file according to the different modes and bandwidths. When testing, the user only needs to select the xml file corresponding to the mode and bandwidth to complete one-key configuration, which is simple and efficient, easy to operate, and improves user experience.

[0048] Of course, the above description is not a limitation of the present application, and the present application is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present application should also be within the scope of the present application.

Claims

1. A SEM measurement method for 5G NR signals, characterized by: Comprising the following steps: Step 1: using full FFT mode, calculate the power value of the input signal; Specifically comprising the following steps: Step S11: read the signal waveform file, and calculate the IQ data length of the waveform file, after one Fourier transform of the length data, the complete frequency domain information of the signal is obtained; Step S12: using the frequency spectrum shift method, the signal spectrum is shifted to the frequency of the carrier signal without distortion; Step S13: after the frequency spectrum shift, the frequency domain information of the whole segment of IQ data is obtained, and according to the sampling rate, signal bandwidth and Fourier transform point number, the position of the signal in the whole data, i.e. the starting position and the ending position, is calculated, and the frequency domain value of all point numbers in the statistical interval is calculated, i.e. the absolute power value of the signal is obtained; Step 2: using segmented FFT mode, obtain the frequency spectrum of the signal, filter out the mutation points of the signal spectrum, and optimize the test results of each frequency range; Specifically comprising the following steps: Step S21: divide the original signal data into several segments according to the Fourier transform point number, and use the windowing or filter method for each segment to filter out the jump points of the frequency spectrum, prevent the frequency spectrum from being messy, and make the frequency spectrum smoother; Step S22: Fourier transform each segment of original data with windowing or filter, to obtain the frequency domain information of the original data, and perform frequency spectrum shift; Step S23: after obtaining the frequency domain information of each segment of original data, the power value of each segment of signal is calculated and superimposed, and the superimposed power value is divided by the number of segments, i.e. the power-averaged frequency spectrum is obtained, since FFT is a linear operation, the final frequency spectrum contains the spectrum characteristics of each segment; Step S24: according to the sampling rate, Fourier transform point number, resolution bandwidth and parameter configuration information of each segment, the interval position of each frequency segment in the power-averaged spectrum, i.e. the starting position and the ending position, is calculated, and the maximum power value in the interval is calculated, which is the SEM test result in the frequency range; Step 3: using multiple traversal-multiple calculation mode, realize the spectrum measurement of each frequency range, traverse and read the user segmentation configuration information, and calculate the spurious of each spectrum; Step 4: using the method of reading xml file, configure the parameters of each frequency range. 2.The SEM measurement method for 5G NR signals according to claim 1, characterized in that: In step 3, specifically comprising the following steps: Step S31: according to the 3GPP protocol, calculate the segmentation configuration information of different bandwidths, including the starting position, ending position, resolution bandwidth and starting and ending position of the limit line of each segment; count all the segmentation information to calculate the measurement range corresponding to the bandwidth; if the frequency spectrum of the frequency domain signal exceeds the measurement range, the excess point number is discarded by taking the two-side truncation method, so that the measurement range is located in the middle position of the frequency spectrum; Step S32: according to the left-to-right mode, the measurement result of each segment is calculated in turn, which contains the maximum power absolute value, the maximum power relative value, the frequency point corresponding to the maximum power and the difference between the maximum power and the limit line, and after traversing all the segments, the overall SEM measurement result of the signal is obtained. 3.The SEM measurement method for 5G NR signals according to claim 1, characterized in that: In step 4, specifically comprising the following steps: Step S41: According to the 3GPP protocol, the segment configuration information of different modes and different bandwidths is counted, and the configuration information includes the start position, the end position, the resolution bandwidth, the filter type, the scanning time, and the start and end positions of the limit line. Step S42: The configuration information is written into the xml configuration file according to the different modes and bandwidths.

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