Payment data interaction transmission method for intelligent terminal

Abstract

The invention relates to the technical field of signal transmission, in particular to a payment data interactive transmission method for an intelligent terminal. The method comprises the following steps: acquiring a peak in a spectrogram corresponding to a test signal received by the NFC payment ring, screening out the peak, and further judging whether Bluetooth signal interference exists or not according to the dispersion degree of the peak; if the Bluetooth signal interference exists, an initial filtering threshold value of band-pass filtering is set for filtering; obtaining a partition effect and a continuity degree factor, and further obtaining signal integrity; screening the peak to obtain a sudden peak; obtaining the noise existence degree by using the number of the peaks in the initial filtering threshold and the abrupt degree; obtaining a filtering effect of the initial filtering threshold value according to the signal integrity and the noise existence degree; updating the initial filtering threshold value to obtain an updated filtering threshold value; and selecting the updated filtering threshold with the maximum filtering effect for filtering. According to the invention, interference during payment signal interaction between the NFC ring and the NFC terminal can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of signal transmission, and in particular to a payment data interactive transmission method for a smart terminal. Background Art

[0002] NFC payment ring is a smart wearable device with a built-in near field communication (NFC) chip that can be used for contactless payment. It is similar to the mobile payment function of NFC payment cards or smartphones, and can be used for quick payment on NFC-enabled POS machines (NFC terminals) without having to take out mobile phones or bank cards. Most traditional NFC payment rings directly write payment information such as card numbers and passwords through NFC chips. With the development of technology, MCU chips can be installed in payment rings to enable mobile smart terminals to write data to NFC payment rings.

[0003] The data transmission interaction between the MCU chip and the mobile phone terminal is realized through Bluetooth, but the short-range Bluetooth data transmission will affect the transmission data interaction of the NFC chip, and filters are often required to filter and clean the transmission data. The NFC transmission signal is located near 13.56MHz, and the existing algorithm can usually use bandpass filtering to filter out the frequency signals outside the fixed filter threshold around 13.56MHz.

[0004] However, the filtering effect of the bandpass filter with a fixed filtering threshold in the prior art is unstable. The bandpass filter with a higher threshold may introduce too many interference signals, and the bandpass filter with a lower threshold may filter out the original NFC payment signal. Therefore, the bandpass filter with a fixed filtering threshold has poor adaptability to NFC payment signal transmission in different scenarios, and a stable and adaptable filtering method is urgently needed. Summary of the invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a payment data interactive transmission method for a smart terminal, and the technical solution adopted is as follows: An embodiment of the present invention provides a payment data interactive transmission method for a smart terminal, the method comprising: Convert the test signal received by the NFC payment ring into a spectrum diagram; obtain the peaks in the spectrum diagram, filter out the peaks, and obtain the peak dispersion degree according to the distance between each peak and the two adjacent peaks on the left and right; Determine whether there is Bluetooth signal interference based on the degree of peak dispersion; if there is Bluetooth signal interference, set the initial filtering threshold of the bandpass filter for filtering; The cutoff effect is obtained according to the distance between the left and right adjacent peaks of the left threshold and the right threshold in the initial filtering threshold; the continuity factor is obtained according to the peak difference between every two adjacent peaks within the initial filtering threshold and outside the initial filtering threshold; the cutoff effect and the continuity factor are multiplied to obtain the signal integrity; The peaks are screened to obtain the peaks according to the peak difference between each peak and the adjacent peaks; the noise existence degree is obtained by using the number and abruptness of the peaks within the initial filtering threshold; the filtering effect of the initial filtering threshold is obtained according to the signal integrity and the noise existence degree; The initial filtering threshold is updated to obtain an updated filtering threshold; and the updated filtering threshold with the greatest filtering effect is selected for filtering.

[0006] Preferably, obtaining the peaks in the spectrum graph and screening out the peaks includes: The AMPD peak search algorithm is used to obtain all the peaks in the spectrum diagram; the peak values ​​of all the peaks are normalized to obtain the peak values ​​of the normalized peaks; the screening threshold is set, when the threshold value of the normalized peak is less than or equal to the screening threshold value, the peak is a low peak, and when the threshold value of the normalized peak is greater than the screening threshold value, the peak is a high peak.

[0007] Preferably, the peak dispersion degree is obtained according to the distance between each peak and two adjacent peaks on the left and right, including: Get the distance between each peak in the spectrum graph and the two adjacent peaks on the left and right to form a distance set; calculate the variance of the distance set as the peak discreteness.

[0008] Preferably, judging whether there is Bluetooth signal interference according to the degree of peak dispersion includes: The peak dispersion degree is normalized and a first threshold is set. If the normalized peak dispersion degree is greater than or equal to the first threshold, Bluetooth signal interference exists.

[0009] Preferably, obtaining a partition effect comprises: The sum of the distance between two adjacent peaks on the left and right of the left threshold in the initial filtering threshold and the distance between two adjacent peaks on the right and left of the right threshold is obtained, and recorded as the partition effect.

[0010] Preferably, the continuity factor is obtained according to the peak value difference between every two adjacent peaks within the initial filtering threshold and outside the initial filtering threshold, including: The average value of the absolute value of the peak difference between every two adjacent peaks within the initial filtering threshold is obtained and the inverted value is obtained to obtain the degree of continuity within the threshold; the average value of the absolute value of the peak difference between every two adjacent peaks outside the initial filtering threshold is obtained and the inverted value is obtained to obtain the degree of continuity outside the threshold; the ratio of the degree of continuity within the threshold to the degree of continuity outside the threshold is the continuity factor.

[0011] Preferably, the peaks are screened according to the peak value difference between each peak and an adjacent peak to obtain the sudden peak, comprising: The absolute values ​​of the differences between a peak and the peaks of the two adjacent peaks on the left and right are calculated and summed up, and the summed results are normalized to obtain the neighborhood distribution characteristic value of the peak; if the neighborhood distribution characteristic value of the peak is greater than the segmentation threshold, the peak is a sudden peak.

[0012] Preferably, the noise presence level is obtained by using the number and abruptness of the peaks within the initial filtering threshold, including: Calculate the sum of the absolute values ​​of the differences between a peak and the peaks of the two adjacent high peaks on the left and right, and record it as the adjacent difference of the peak; obtain the sum of the adjacent differences of all peaks within the initial filtering threshold, and record it as the abruptness; multiply the number of peaks within the initial filtering threshold by the abruptness to obtain the degree of noise existence.

[0013] Preferably, obtaining the filtering effect of the initial filtering threshold according to the signal integrity and the degree of noise existence includes: The inverse of the noise presence and the signal integrity are normalized and then summed to obtain the filtering effect of the initial filtering threshold.

[0014] Preferably, updating the initial filtering threshold to obtain an updated filtering threshold includes: The update amplitude is set, and the left threshold and the right threshold in the initial filter threshold are synchronously updated by using the update amplitude to obtain the updated filter threshold; each update includes an increase in the left threshold and a decrease in the right threshold, and the increase or decrease amplitude is the update amplitude.

[0015] The embodiments of the present invention have at least the following beneficial effects: before the NFC payment ring transmits the payment signal to the NFC terminal, the present application first transmits a test signal, and then converts the test signal received by the NFC payment ring into a spectrum diagram, analyzes the peak in the spectrum diagram, determines whether filtering is required, and normal transmission without filtering can improve the transmission efficiency; further, for the signal that needs to be filtered due to interference from the Bluetooth signal, based on the characteristic difference between the NFC modulation signal and the Bluetooth interference signal, the integrity of the filtered signal is obtained according to the peak within the filtering threshold in the spectrum diagram of the test signal and the peak at the boundary of the filtering threshold (left threshold and right threshold), so as to ensure the integrity of the filtered NFC modulation signal, and then obtain the sudden peak in the peak, obtain the degree of noise after filtering according to the sudden peak, and then combine the two to evaluate the advantages and disadvantages of the filtering threshold from two aspects: signal integrity and the retention of noise after filtering, and finally update the initial filtering threshold, and screen out the optimal filtering threshold according to the filtering effect corresponding to the filtering threshold after each update, so as to obtain a relatively accurate bandpass filtering threshold when the payment signal is transmitted, and improve the integrity and accuracy of the payment signal in the interactive transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention 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 invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A method flow chart of a payment data interactive transmission method for a smart terminal provided by an embodiment of the present invention; Figure 2 A schematic diagram of a spectrum diagram of a payment data interactive transmission method for a smart terminal provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the payment data interactive transmission method for a smart terminal proposed by the present invention, 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.

[0019] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0020] The following is a detailed description of a payment data interactive transmission method for a smart terminal provided by the present invention in conjunction with the accompanying drawings. Example

[0021] The main application scenarios of the present invention are: When the NFC payment ring is interacting with the NFC terminal for payment, if the smart terminal is used to adjust the payment data of the NFC payment ring, the NFC payment signal may be interfered by the Bluetooth data, resulting in inaccurate payment data transmission. A filter is required for filtering. The fixed threshold of the existing bandpass filtering algorithm is unstable in filtering out Bluetooth interference, and the threshold needs to be adjusted according to the real-time situation of Bluetooth interference noise in the delivery scenario.

[0022] See also Figure 1 , which shows a method flow chart of a payment data interactive transmission method for a smart terminal provided by an embodiment of the present invention, the method comprising the following steps: Step S1, converting the test signal received by the NFC payment ring into a spectrum diagram; obtaining the peaks in the spectrum diagram, and filtering out the peaks, and obtaining the peak dispersion degree according to the distance between each peak and the two adjacent peaks on the left and right.

[0023] Before transmitting the official payment signal to the NFC terminal, the NFC payment ring needs to transmit multiple sets of test signals, where the content of the test signal is the same as the payment signal.

[0024] After receiving the test signal, the NFC terminal transmits a reply signal to the NFC payment ring. The signal content is the same as the test signal. After receiving the test reply signal, the NFC payment ring performs subsequent analysis to detect noise interference in the transmission channel.

[0025] The transmission signal in the process is mainly a modulated signal in the range of 13.56MHz, in the format of time series data, and each data point is the signal strength at the corresponding time. For the test signal received by the NFC payment ring, the time series data is converted into a spectrum diagram using Fourier transform, with the horizontal axis of the spectrum diagram being frequency and the vertical axis being signal strength.

[0026] Before NFC sends a payment signal, it first sends a test signal to test the channel. If there is no channel anomaly, the signal is directly transmitted; otherwise, if there is a channel anomaly, the filter threshold corresponding to the adaptive bandpass filter is obtained according to the anomaly characteristics. The spectrum of the test signal usually contains NFC modulation signal, white noise, and Bluetooth interference signal in the current scenario, such as Figure 2 As shown in the figure, the NFC modulation signal is usually concentrated near the carrier frequency of 13.56MHz, and the main energy is distributed near the carrier frequency and its sidebands. The signal strength is strongest at 13.56MHz, and the modulation frequency signal strength gradually decreases on both sides. In addition to the modulation signal, there are many white noises with smaller signal strengths distributed in the spectrum, evenly distributed in the frequency domain. The Bluetooth interference signal also has a strong signal strength, which is not evenly distributed like white noise, but locally concentrated, usually with multiple concentrated frequency points.

[0027] Furthermore, the AMPD peak search algorithm is used to obtain all the peaks in the spectrum diagram, where most of the peaks in the spectrum diagram are white noise peaks, which are lower than the peaks caused by the modulation signal and the Bluetooth interference signal. Therefore, the peak values ​​of all the peaks are normalized to obtain the peak values ​​of the normalized peaks. After normalization, the low peaks of white noise and the high peaks caused by the NFC modulation signal or suspected Bluetooth transmission can be obtained at both ends. Then the screening threshold is set. When the threshold of the normalized peak is less than or equal to the screening threshold, the peak is a low peak. When the threshold of the normalized peak is greater than the screening threshold, the peak is a high peak. The reference value of the screening threshold is 0.5, and the implementer can adjust it according to the actual situation, such as performing a Rayleigh distribution test on the low peak and adjusting the threshold according to the test results.

[0028] For the peaks obtained, according to the global distribution characteristics of the peaks, if all the peaks are clustered in the global distribution of the spectrum diagram, it means that all the peak waves are concentrated near the main carrier frequency, and there is no abnormality in the current channel; if there is a certain degree of discrete distribution of peaks, the distribution of global peaks is low, indicating that there is suspected Bluetooth interference in the current signal and filtering is required.

[0029] Get the distance between each peak in the spectrum graph and the two adjacent peaks on the left and right to form a distance set. The distance is also the distance on the horizontal axis between the two peaks. Calculate the variance of the distance set as the peak dispersion degree. The greater the peak dispersion degree, the more discrete the peak distribution in the current signal spectrum graph, and the Bluetooth signal interference is suspected to exist in the channel.

[0030] Step S2, judging whether there is Bluetooth signal interference according to the degree of peak dispersion; if there is Bluetooth signal interference, setting an initial filtering threshold of the bandpass filter to perform filtering.

[0031] When the channel is normal, the signal frequency distribution of NFC in the spectrum is concentrated, and the variance of the distance between peaks is extremely low compared to the variance of the distance between Bluetooth noise signals; further, the peak dispersion is normalized, and the first threshold is set to separate the normal channel from the situation where Bluetooth signal interference exists in the channel. If the normalized peak dispersion is greater than or equal to the first threshold, Bluetooth signal interference exists. The reference value of the first threshold is 0.5, and the implementer can adjust it according to the actual situation.

[0032] When the channel is normal, the signal frequency distribution of NFC in the spectrum diagram is concentrated, and the variance of the distance between peaks is extremely low compared to the variance of the distance between Bluetooth noise signals. Therefore, after normalization, the peak dispersion degree of the Bluetooth noise signal and the suspected abnormality degree of the absence of the Bluetooth signal show a two-level differentiation trend. Therefore, setting the first threshold to the midpoint of 0.5 can basically separate the normal channel from the abnormal situation in the channel. When the normalized value of the peak dispersion degree of the channel is greater than or equal to 0.5, it is considered that there is Bluetooth interference abnormality in the current transmission channel.

[0033] If there is interference from Bluetooth signals, a bandpass filter is required for filtering, so an initial filtering threshold is set, and filtering is performed based on the initial filtering threshold using bandpass filtering. There are two filtering thresholds for bandpass filtering, which are usually two centrally symmetrical filtering thresholds in actual signal data filtering. Frequency waves outside the filtering thresholds are filtered out, and frequency wave signals within the two filtering thresholds are retained, and the two initial filtering thresholds are divided into a left threshold and a right threshold.

[0034] Step S3, obtaining the isolation effect according to the distance between the left and right adjacent peaks of the left threshold and the right threshold in the initial filtering threshold; obtaining the continuity factor according to the peak difference between every two adjacent peaks within the initial filtering threshold and outside the initial filtering threshold; and multiplying the isolation effect and the continuity factor to obtain the signal integrity.

[0035] The desired result after filtering is usually to filter out the noise signal caused by Bluetooth interference as much as possible, while retaining the complete NFC data as much as possible. Therefore, an evaluation model is constructed here through two indicators of data distribution characteristics in the frequency domain. The first is the integrity of the NFC modulation signal in the test signal. The more complete the NFC modulation signal within the filtering threshold, the lower the loss of the original transmission information by filtering, and the more complete the retained information; the second is the existence of the noise signal. The lower the existence of the noise signal within the bandpass threshold, the better the noise filtering effect under the corresponding threshold, so as to evaluate the filtering effect of the bandpass filtering.

[0036] The integrity of the NFC modulation signal in the test signal is mainly to detect and avoid the situation where the filter threshold is located in the NFC modulation signal area, which cuts off the NFC modulation signal and causes an incomplete signal. The integrity of the NFC modulation signal is obtained by the ratio of the continuity of the peak value within the threshold to the continuity of the peak value outside the threshold and the continuity at the threshold. The peak corresponds to the NFC modulation signal. When there are continuous peaks at the filter threshold, it means that the filter threshold may cut off the NFC modulation signal. The more continuous modulation signals are distributed on both sides of the filter threshold, the weaker the integrity of the NFC modulation signal. When there are more and more continuous peaks within the filter threshold than outside the filter threshold, it means that there are more and more continuous modulation signal distributions within the filter threshold. The higher the integrity of the NFC signal within the corresponding filter threshold, the higher the signal integrity is until there are no continuous peaks outside the filter threshold, and the signal integrity within the threshold filter reaches the highest.

[0037] Furthermore, the closer the distance between the two left and right peaks closest to the left threshold and the distance between the two left and right peaks closest to the right threshold are, the more likely it is that the initial filtering threshold is in the continuous signal segment, the NFC modulated signal is cut off, and the integrity of the NFC modulated signal is worse.

[0038] The isolation effect is obtained according to the distance between the left and right adjacent peaks of the left threshold and the right threshold in the initial filtering threshold. Specifically, the sum of the distance between the two left and right adjacent peaks of the left threshold in the initial filtering threshold and the distance between the two left and right adjacent peaks of the right threshold in the initial filtering threshold is obtained, and recorded as the isolation effect. The greater the isolation effect, the stronger the integrity of the NFC modulated signal. The smaller the isolation effect, the more likely the initial filtering threshold exists in the continuous peak distribution, and the more likely the initial filtering threshold is to isolate the NFC modulated signal, and the worse the integrity of the NFC modulated signal.

[0039] Next, the continuity within the initial filtering threshold and outside the initial filtering threshold is analyzed, and the initial filtering threshold refers to the range between the left threshold and the right threshold. The continuity factor is obtained according to the peak difference between every two adjacent peaks within the initial filtering threshold and outside the initial filtering threshold. Specifically, the average value of the absolute value of the peak difference between every two adjacent peaks within the initial filtering threshold is obtained and inverted to obtain the continuity within the threshold; the average value of the absolute value of the peak difference between every two adjacent peaks outside the initial filtering threshold is obtained and inverted to obtain the continuity outside the threshold; the ratio of the continuity within the threshold to the continuity outside the threshold is the continuity factor.

[0040] The specific calculation model of the continuity within the threshold and the continuity outside the threshold is: , , in, and They represent the degree of continuity within the threshold and the degree of continuity outside the threshold respectively; and Represents the number of peaks within and outside the initial filtering threshold, respectively. is the peak value (i.e. signal strength value) of the ith peak in the horizontal direction within the initial filtering threshold, is the peak value of the peak after the ith peak, It represents the absolute value of the difference between the peak values ​​of two peaks. The smaller the value is, the lower the degree of change between the two peaks is, the higher the degree of continuity is, and the gradual change is continuous.

[0041] It is the difference between the peak values ​​of all the peaks within the initial filtering threshold and the mean value. The smaller the mean value is, the higher the continuity of all the peaks within the initial filtering threshold is. Therefore, the inverse proportional form is adopted. ; It is the sum of the differences between the peaks outside the initial filtering threshold. The larger the sum is, the higher the continuity of all the peaks outside the initial filtering threshold is. It is in inverse proportion. ; It is the ratio of the continuity of the peaks inside and outside the initial filtering threshold, that is, the continuity factor. The larger the ratio is, the stronger the continuity of the peaks inside the initial filtering threshold is compared with that outside the initial filtering threshold. This value will reach the maximum when the initial filtering threshold is blocked between the continuous NFC modulation signal and the discontinuous abnormal signal. At this time, the ratio is the largest.

[0042] Finally, the signal integrity of the NFC modulated signal can be obtained by combining the isolation effect and the continuity factor when filtering using the initial filtering threshold. The signal integrity is obtained by multiplying the isolation effect and the continuity factor. The greater the signal integrity, the better the filtering effect and the more complete the retained NFC modulated signal.

[0043] Step S4, screening the peaks according to the peak difference between each peak and the adjacent peak to obtain the sudden peaks; using the number and abruptness of the sudden peaks within the initial filtering threshold to obtain the degree of noise; obtaining the filtering effect of the initial filtering threshold according to the signal integrity and the degree of noise.

[0044] After completely analyzing the filtered signal, it is also necessary to analyze the degree of noise after filtering. Here, the signal peak corresponding to the Bluetooth signal interference is obtained according to the neighborhood distribution characteristics of the peak. Obtain the neighborhood adjacent differences of all peaks. Because the NFC modulation signal distribution is clustered and changes continuously and slowly, its peak and adjacent data may all be peaks, and the adjacent differences are small; while the Bluetooth interference signal is discretely distributed and appears suddenly, and the difference between its peak and adjacent data is large. Therefore, the difference between the two types of peaks is large. After linear normalization, two types of data can be obtained at both ends of the value range. Here, the median value of 0.5 can be taken as the segmentation threshold, and the peaks are divided by the neighborhood distribution characteristic value. When the neighborhood distribution characteristic value is greater than the segmentation threshold, the peak is considered to be a peak with Bluetooth signal interference characteristics.

[0045] According to the peak difference between each peak and the adjacent peak, the peaks are screened to obtain the sudden peaks. Specifically, the absolute value of the difference between a peak and the peaks of the two adjacent peaks on the left and right is calculated and summed, and the summed result is normalized to obtain the neighborhood distribution characteristic value of the peak; if the neighborhood distribution characteristic value of the peak is greater than the segmentation threshold, the peak is a sudden peak. The calculation model of the neighborhood distribution characteristic value is: , in, is the neighborhood distribution characteristic value of the p-th peak, is the peak value of the pth peak, is the peak value of the peak before the pth peak, is the peak value of the peak after the pth peak, is the peak difference before and after the p-th peak. The larger the difference, the greater the difference between the p-th peak and the adjacent peak, and the more likely it is a sudden peak. is linear normalization. Thus, we obtain the peaks with neighborhood distribution eigenvalues ​​greater than 0.5.

[0046] The existence degree of noise signal is obtained by the difference between the peak within the threshold and other peaks. Generally, the NFC main frequency signal occupies the main peak at 13.56MHz. When the Bluetooth interference signal exists in the continuous modulation signal of NFC, the Bluetooth interference signal will exist at the edge of the continuous NFC signal extending to both sides of the main peak. Therefore, the more the number of peaks within the initial filtering threshold is compared with other peaks, and the greater the difference between the peaks and the adjacent peaks, it means that there are more peaks with Bluetooth interference signal characteristics within the threshold, and the more prominent the peaks are, the stronger the interference degree of Bluetooth interference signal is, and the stronger the data abnormality within the threshold is.

[0047] The degree of noise is obtained by using the number and abruptness of the peaks within the initial filtering threshold. Specifically, the sum of the absolute values ​​of the differences between a peak and the peaks of the two adjacent high peaks on the left and right is calculated, which is recorded as the adjacent difference of the peak; the sum of the adjacent differences of all peaks within the initial filtering threshold is obtained, which is recorded as the abruptness; the number of peaks and the abruptness within the initial filtering threshold are multiplied to obtain the degree of noise.

[0048] The calculation model of the noise existence degree is as follows: , Among them, C represents the degree of noise corresponding to the initial filtering threshold, Indicates the number of peaks within the initial filtering threshold. The greater the number, the stronger the noise within the threshold. is the peak value of the ith peak, It is the peak difference between the ith peak and the adjacent peaks before and after it, that is, the adjacent difference. The larger the adjacent difference, the more abrupt the ith peak is. The stronger the signal strength of the peak relative to the adjacent NFC signal, the stronger the interference to the NFC signal. The adjacent differences of all the peaks are comprehensively accumulated. The larger the accumulated sum is, the more abrupt the peak within the threshold is, and the stronger the noise within the threshold is.

[0049] Combining the above two evaluation features (signal integrity and noise presence), the stronger the signal integrity of the NFC modulated signal, the lower the noise presence, and the better the filtering effect of the corresponding initial filtering threshold. The filtering effect of the initial filtering threshold is obtained according to the signal integrity and noise presence. Specifically, the inverse of the noise presence and the signal integrity are normalized and then summed to obtain the filtering effect of the initial filtering threshold. The purpose of normalization is to unify the magnitude of the two evaluation features, so that the index for evaluating the filtering quality when performing bandpass filtering with different filtering thresholds can be obtained.

[0050] Step S5, updating the initial filtering threshold to obtain an updated filtering threshold; selecting the updated filtering threshold with the greatest filtering effect for filtering.

[0051] In actual filtering, 2MHz around 13.56MHz can usually be taken as the maximum upper and lower thresholds, so the initial filtering threshold is set to 13.56±2MHz. Further, the initial filtering threshold is updated. Specifically, the update amplitude is set, and the left threshold and the right threshold in the initial filtering threshold are synchronously updated using the update amplitude to obtain the updated filtering threshold. Each update includes an increase in the left threshold and a decrease in the right threshold. The increase or decrease amplitude is the update amplitude, which is 0.1MHz. The implementer can adjust it according to the actual effect. After each update, the updated updated filtering threshold is used to filter the test signal and obtain the filtering effect. The updated filtering threshold with the largest filtering effect is selected to filter the payment signal. The NFC modulation signal integrity is the strongest and the noise is the lowest under this filtering threshold. As the filtering threshold in the payment data interactive transmission process, it can filter out Bluetooth interference signals to the greatest extent while retaining the integrity of the NFC modulation signal.

[0052] To summarize, traditional filtering usually uses a fixed filtering threshold to filter out signals other than NFC modulated signals in payment signals. However, there may be interference from Bluetooth signals at the internal edges of NFC's continuous modulated signals, and the traditional fixed threshold cannot filter out such interference. This application evaluates the optimal threshold by constructing an evaluation model. The obtained filtering threshold comprehensively considers the signal integrity within the threshold and the severity of the noise interference within the threshold. The obtained filtering threshold can shrink inward for filtering when there is strong Bluetooth interference noise in the NFC modulated signal. When the Bluetooth interference noise in the NFC modulated signal is weak, the threshold width can be increased to ensure the integrity of the NFC modulated signal.

[0053] When using the NFC payment ring to transmit data to the NFC terminal, the transmitted payment signal is filtered using the filter threshold of the bandpass filter obtained through the real-time test signal, and the filtered payment signal is obtained as the actual transmission data. This prevents the noise interference of the payment data transmission channel under the influence of the Bluetooth environment of the NFC payment ring, and better realizes the noise removal and original data integrity preservation during the payment signal transmission process.

[0054] It should be noted that the sequence of the above embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The above is a description of a specific embodiment of this 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.

[0055] 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.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A payment data interactive transmission method for a smart terminal, characterized in that: The method includes: Convert the test signal received by the NFC payment ring into a spectrum diagram; obtain the peaks in the spectrum diagram, filter out the peaks, and obtain the peak dispersion degree according to the distance between each peak and the two adjacent peaks on the left and right; Determine whether there is Bluetooth signal interference based on the degree of peak dispersion; if there is Bluetooth signal interference, set the initial filtering threshold of the bandpass filter for filtering; The cutoff effect is obtained according to the distance between the left and right adjacent peaks of the left threshold and the right threshold in the initial filtering threshold; the continuity factor is obtained according to the peak difference between every two adjacent peaks within the initial filtering threshold and outside the initial filtering threshold; the cutoff effect and the continuity factor are multiplied to obtain the signal integrity; The peaks are screened to obtain the peaks according to the peak difference between each peak and the adjacent peaks; the noise existence degree is obtained by using the number and abruptness of the peaks within the initial filtering threshold; the filtering effect of the initial filtering threshold is obtained according to the signal integrity and the noise existence degree; The initial filtering threshold is updated to obtain an updated filtering threshold; and the updated filtering threshold with the greatest filtering effect is selected for filtering.

2. A payment data interactive transmission method for a smart terminal according to claim 1, characterized in that: The step of obtaining peaks in the spectrum graph and filtering out the peaks includes: The AMPD peak search algorithm is used to obtain all the peaks in the spectrum diagram; the peak values ​​of all the peaks are normalized to obtain the peak values ​​of the normalized peaks; the screening threshold is set, when the threshold value of the normalized peak is less than or equal to the screening threshold value, the peak is a low peak, and when the threshold value of the normalized peak is greater than the screening threshold value, the peak is a high peak.

3. A payment data interactive transmission method for a smart terminal according to claim 1, characterized in that: The step of obtaining the peak dispersion degree according to the distance between each peak and two adjacent peaks on the left and right includes: Get the distance between each peak in the spectrum graph and the two adjacent peaks on the left and right to form a distance set; calculate the variance of the distance set as the peak discreteness.

4. A payment data interactive transmission method for a smart terminal according to claim 1, characterized in that: The determining whether there is Bluetooth signal interference according to the degree of peak dispersion includes: The peak dispersion degree is normalized and a first threshold is set. If the normalized peak dispersion degree is greater than or equal to the first threshold, Bluetooth signal interference exists.

5. A payment data interactive transmission method for a smart terminal according to claim 1, characterized in that: The obtaining of the partition effect comprises: The sum of the distance between two adjacent peaks on the left and right of the left threshold in the initial filtering threshold and the distance between two adjacent peaks on the right and left of the right threshold is obtained, and recorded as the partition effect.

6. A payment data interactive transmission method for a smart terminal according to claim 1, characterized in that: The step of obtaining the continuity factor according to the peak value difference between every two adjacent peaks within the initial filtering threshold and outside the initial filtering threshold comprises: The average value of the absolute value of the peak difference between every two adjacent peaks within the initial filtering threshold is obtained and the inverted value is obtained to obtain the degree of continuity within the threshold; the average value of the absolute value of the peak difference between every two adjacent peaks outside the initial filtering threshold is obtained and the inverted value is obtained to obtain the degree of continuity outside the threshold; the ratio of the degree of continuity within the threshold to the degree of continuity outside the threshold is the continuity factor.

7. A payment data interactive transmission method for a smart terminal according to claim 1, characterized in that: The step of screening the peaks according to the peak difference between each peak and the adjacent peaks to obtain the sudden peaks comprises: The absolute values ​​of the differences between a peak and the peaks of the two adjacent peaks on the left and right are calculated and summed up, and the summed results are normalized to obtain the neighborhood distribution characteristic value of the peak; if the neighborhood distribution characteristic value of the peak is greater than the segmentation threshold, the peak is a sudden peak.

8. A payment data interactive transmission method for a smart terminal according to claim 1, characterized in that: The method of obtaining the degree of noise existence by using the number and abruptness of the peaks within the initial filtering threshold comprises: Calculate the sum of the absolute values ​​of the differences between a peak and the peaks of the two adjacent high peaks on the left and right, and record it as the adjacent difference of the peak; obtain the sum of the adjacent differences of all peaks within the initial filtering threshold, and record it as the abruptness; multiply the number of peaks within the initial filtering threshold by the abruptness to obtain the degree of noise existence.

9. A payment data interactive transmission method for a smart terminal according to claim 1, characterized in that: The filtering effect of obtaining the initial filtering threshold according to the signal integrity and the noise existence degree includes: The inverse of the noise presence and the signal integrity are normalized and then summed to obtain the filtering effect of the initial filtering threshold.

10. A payment data interactive transmission method for a smart terminal according to claim 1, characterized in that: The updating of the initial filtering threshold to obtain an updated filtering threshold includes: The update amplitude is set, and the left threshold and the right threshold in the initial filter threshold are synchronously updated by using the update amplitude to obtain the updated filter threshold; each update includes an increase in the left threshold and a decrease in the right threshold, and the increase or decrease amplitude is the update amplitude.

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