Methods, procedures and apparatus for narrowband signal detection, frequency estimation and interference cancellation

Abstract

The application discloses a narrow-band signal detection, frequency estimation and interference signal elimination method, a computer program product and a wireless local area network communication device. The narrow-band signal detection method is used for detecting a narrow-band signal from IQ sampling data, and the method comprises the following steps: counting the run length of positive numbers or negative numbers in in-phase sampling data or quadrature sampling data and the occurrence frequency of each run length to obtain a run length distribution; calculating the concentration of the run length based on the run length distribution; judging whether the concentration of the run length is high enough; and determining that the narrow-band signal is detected in response to the concentration of the run length being high enough. The method disclosed by the application has the characteristics of small calculation amount.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of signal detection, parameter estimation and interference cancellation, in particular, to a narrowband signal detection, frequency estimation and narrowband interference signal cancellation method, a computer program product and a wireless local area network communication device. BACKGROUND

[0002] Different wireless communication signals working in unlicensed band usually interfere with each other, resulting in the decline of reception performance. For example, wireless local area network (WLAN) and Bluetooth signals share some frequency bands in the 2.4G frequency band, resulting in mutual interference between the two. The interference of Bluetooth signals may cause the false alarm probability of packet detection of the WLAN receiver to increase and the packet demodulation performance to decline.

[0003] In some WLAN receivers, Bluetooth signal interference is cancelled by detecting the Bluetooth signal in real time and estimating the frequency and power of the Bluetooth signal. Since the time and frequency of the Bluetooth signal interference are random, the WLAN receiver needs to continuously detect the Bluetooth signal, so the computational complexity of the detection method should be as low as possible to reduce the power consumption of the WLAN receiver.

[0004] Compared with WLAN signals, Bluetooth signals are narrowband signals. A commonly used narrowband signal detection method is to perform fast Fourier transform (FFT) on the received signal, and then analyze the frequency domain signal to determine whether a narrowband signal exists and estimate the frequency of the narrowband signal. However, although the above method uses FFT for calculation, the computational complexity is still high. SUMMARY

[0005] An object of the present application is to provide a narrowband signal detection method, a frequency estimation method and a computer program product to reduce the complexity of narrowband signal detection and frequency estimation. Another object of the present application is to provide a narrowband interference signal cancellation method and a wireless local area network communication device using the method, which uses the above narrowband signal detection method and frequency estimation method to detect the frequency of the narrowband interference signal and uses a notch filter to cancel the narrowband interference signal. Since the method has low computational complexity, the wireless local area network communication device using the method has low power consumption.

[0006] In a first aspect, the present application provides a method for detecting a narrowband signal from IQ sample data, the IQ sample data comprising in-phase sample data and quadrature sample data, the method comprising: counting the run length of positive or negative numbers and the occurrence number of each run length in the in-phase sample data or the quadrature sample data to obtain a run length distribution; calculating the concentration of run length based on the run length distribution; determining whether the concentration of run length is high enough; and determining that the narrowband signal is detected in response to the concentration of run length being high enough.

[0007] Optionally, before counting the run length of positive or negative numbers and the occurrence number of each run length in the in-phase sample data or the quadrature sample data, the method further comprises: removing direct current from the IQ sample data.

[0008] In some embodiments, calculating the concentration of run length based on the run length distribution and determining whether the concentration of run length is high enough comprises: calculating the variance or average difference of run length based on the run length distribution; and determining whether the variance or average difference is lower than a preset threshold, and confirming that the concentration of run length is high enough if the variance or average difference is lower than the preset threshold.

[0009] Optionally, before calculating the concentration of run length based on the run length distribution, the method further comprises performing any one or several of the following operations on the run length distribution:

[0010] (1) setting the occurrence number corresponding to the run length smaller than a preset run length threshold in the run length distribution to 0;

[0011] (2) setting the occurrence number smaller than a preset occurrence number threshold in the run length distribution to 0;

[0012] (3) setting the occurrence number corresponding to the run length whose product of run length and occurrence number is smaller than a preset proportion threshold in the run length distribution to 0.

[0013] Optionally, the IQ sample data is the IQ sample data of a wireless local area network receiver, and the narrowband signal is a Bluetooth signal.

[0014] In a second aspect, the present application provides a narrowband signal frequency estimation method for estimating the frequency of a narrowband signal from IQ sampling data, the IQ sampling data comprising in-phase sampling data and quadrature sampling data, the method comprising: counting the run length of positive numbers or negative numbers in the in-phase sampling data or the quadrature sampling data and the occurrence number of each run length to obtain a run length distribution; calculating the mean of the run length based on the run length distribution; calculating the frequency size estimation value of the narrowband signal based on the sampling rate of the IQ sampling data and the mean of the run length; and determining the frequency sign of the narrowband signal by using any of the following methods:

[0015] (1) subtracting the quadrature sampling data from the in-phase sampling data to obtain in-phase and quadrature sampling data difference; comparing the phase relationship between the in-phase and quadrature sampling data difference and the in-phase sampling data; if the phase of the in-phase and quadrature sampling data difference leads the phase of the in-phase sampling data, determining that the frequency sign of the narrowband signal is positive; if the phase of the in-phase and quadrature sampling data difference lags behind the phase of the in-phase sampling data, determining that the frequency sign of the narrowband signal is negative;

[0016] (2) subtracting the in-phase sampling data from the quadrature sampling data to obtain quadrature and in-phase sampling data difference; comparing the phase relationship between the quadrature and in-phase sampling data difference and the quadrature sampling data; if the phase of the quadrature and in-phase sampling data difference leads the phase of the quadrature sampling data, determining that the frequency sign of the narrowband signal is negative; if the phase of the quadrature and in-phase sampling data difference lags behind the phase of the in-phase sampling data, determining that the frequency sign of the narrowband signal is positive.

[0017] Optionally, before counting the run length of positive numbers or negative numbers in the in-phase sampling data or the quadrature sampling data and the occurrence number of each run length, the method further comprises: removing direct current from the IQ sampling data.

[0018] In some embodiments, comparing the phase relationship between the in-phase and quadrature sampling data difference and the in-phase sampling data comprises: comparing the size of the in-phase sampling data and the quadrature sampling data corresponding to the tail sampling moment of the positive number run in the in-phase and quadrature sampling data difference, wherein the number of times that the in-phase sampling data is greater than the quadrature sampling data is represented as C1, and the number of times that the quadrature sampling data is greater than the in-phase sampling data is represented as C2; if C1 / (C1+C2) is greater than a preset polarity threshold, it is determined that the phase of the in-phase and quadrature sampling data difference leads the phase of the in-phase sampling data; if C2 / (C1+C2) is greater than the preset polarity threshold, it is determined that the phase of the in-phase and quadrature sampling data difference lags behind the phase of the in-phase sampling data.

[0019] In some embodiments, the comparing the phase relationship between the quadrature and in-phase sample data difference and the quadrature sample data comprises: comparing magnitudes of the quadrature sample data and the in-phase sample data corresponding to tail sample instants of positive number runs in the quadrature and in-phase sample data difference, wherein the number of times that the quadrature sample data is greater than the in-phase sample data is denoted as C1, and the number of times that the in-phase sample data is greater than the quadrature sample data is denoted as C2; if C1 / (C1+C2) is greater than a preset polarity threshold, it is determined that the phase of the quadrature and in-phase sample data difference leads the phase of the quadrature sample data; and if C2 / (C1+C2) is greater than the preset polarity threshold, it is determined that the phase of the quadrature and in-phase sample data difference lags the phase of the quadrature sample data.

[0020] In some embodiments, the IQ sample data is IQ sample data of a wireless local area network receiver, and the narrowband signal is a Bluetooth signal.

[0021] In a third aspect of the present application, a narrowband interference signal elimination method is provided for eliminating a narrowband interference signal in IQ sample data, the IQ sample data comprising in-phase sample data and quadrature sample data, the method comprising: detecting whether a narrowband interference signal exists in the IQ sample data using the narrowband signal detection method described above; estimating a frequency size estimate and a frequency sign of the narrowband interference signal using the narrowband signal frequency estimation method described above, thereby obtaining the frequency of the narrowband interference signal; and filtering the IQ sample data using a notch filter with a notch center frequency equal to the frequency of the narrowband interference signal, thereby obtaining a filtered signal.

[0022] In a fourth aspect of the present application, a computer program product is provided, comprising machine executable instructions which, when executed, perform the narrowband signal detection method described above.

[0023] In a fifth aspect of the present application, a computer program product is provided, comprising machine executable instructions which, when executed, perform the narrowband signal frequency estimation method described above.

[0024] In a sixth aspect of the present application, a wireless local area network communication device is provided, comprising a notch filter, a processor, and a non-transitory storage medium storing computer executable instructions, the computer executable instructions being executable by the processor to perform the narrowband interference signal elimination method described above.

[0025] The above is a summary of the present application, which may have simplified, generalized, and omitted details, and therefore those skilled in the art should recognize that this section is only illustrative and is not intended to limit the scope of the present application in any way. This summary section is neither intended nor used to identify key or essential features of the claimed subject matter, nor used to build an aid for determining the scope of the claimed subject matter. BRIEF DESCRIPTION OF DRAWINGS

[0026] The above and other features of the present application will become more fully understood from the following detailed description and the accompanying drawings, wherein:

[0027] Figure 1 A block diagram of a zero-IF wireless communication receiver is shown;

[0028] Figure 2 A narrowband signal detection method 100 according to an embodiment of the present disclosure is shown;

[0029] Figure 3 A narrowband signal frequency estimation method 200 according to an embodiment of the present disclosure is shown;

[0030] Figure 4A An implementation method of step 240 is shown;

[0031] Figure 4B Another implementation method of step 240 is shown. DETAILED DESCRIPTION

[0032] In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify

[0033] In the present disclosure, the digital signal obtained by sampling a complex signal is referred to as IQ sampling data. For the convenience of those skilled in the art, the following exemplary description is made with reference to a zero-IF wireless communication receiver as shown in Figure 1 The exemplary description is made with reference to a zero-IF wireless communication receiver as shown in Figure 1In the figure, "Antenna" is an antenna, "LNA" (Low Noise Amplifier) is a low noise amplifier, which is used to amplify the air interface signal, and the amplification factor of the LNA can be adjusted by setting the gain of the LNA; "LO" (Local Oscillator) is a local oscillator, which is used to generate a local oscillation signal, and the local oscillation signal and a 90° phase-shifted signal thereof are mixed with the LNA output signal to obtain two signals, which are in-phase (I) and quadrature (Q) signals, respectively. In the figure, "Antenna" is an antenna, "LNA" (Low Noise Amplifier) is a low noise amplifier, which is used to amplify the air interface signal, and the amplification factor of the LNA can be adjusted by setting the gain of the LNA; "LO" (Local Oscillator) is a local oscillator, which is used to generate a local oscillation signal, and the local oscillation signal and a 90° phase-shifted signal thereof are mixed with the LNA output signal to obtain two signals, which are in-phase (I) and quadrature (Q) signals, respectively.

[0034] For the convenience of description, in the present disclosure, the sampling rate of the IQ sampling data is represented as F s The nth sampling point x[n] can be represented in complex form as x[n] = I[n] + jQ[n], n = 0, 1, 2, …, N-1, where n is the sampling point number, I[n] and Q[n] are the nth sampling points of the in-phase sampling data and the quadrature sampling data, respectively, and N is the length of the IQ sampling data.

[0035] Figure 2 A narrow-band signal detection method 100 according to an embodiment of the present disclosure is shown, which is used to detect a narrow-band signal from IQ sampling data. Since the Bluetooth signal is a narrow-band signal relative to the WLAN signal, the method 100 can be applied to detect whether there is a Bluetooth signal interference from the signal received by the WLAN receiver. Specifically, the method 100 includes the following steps:

[0036] In step 110, the run length of positive numbers or negative numbers in the in-phase sampling data or the quadrature sampling data and the occurrence number of each run length are counted to obtain a run length distribution.

[0037] In this disclosure, a run refers to a sequence of consecutive elements in a data sequence that shares the same property, where the data immediately preceding and following the ends of this sequence do not possess that property. The number of elements in a run is called the run length. For example, a positive run is a sequence of consecutive positive numbers in a data sequence, where the data immediately preceding and following the ends of this sequence are not positive. A negative run is a sequence of consecutive negative numbers in a data sequence, where the data immediately preceding and following the ends of this sequence are not negative. For example, in the data sequence "-2,0,3,4,1,8,-1,-3,-5,0,7,0", positive runs include "3,4,1,8" and "7", with run lengths of 4 and 1 respectively; negative runs include "-2" and "-1,-3,-5", with run lengths of 1 and 3 respectively.

[0038] The number of occurrences of positive runs of length m in the in-phase sampling data is expressed as: The number of occurrences of negative runs is represented as The number of occurrences of positive runs of length m in the orthogonal sampling data is expressed as: The number of occurrences of negative runs is represented as

[0039] For narrowband signals, the in-phase component can be approximated as a sine or cosine function, and the quadrature component can be approximated as a sine or cosine function with a phase difference of π / 2 from the in-phase component. Therefore, the statistical results of the positive or negative run lengths of in-phase and quadrature sampled data are essentially the same. Thus, run length statistics can be performed using either in-phase or quadrature sampled data, allowing for the calculation of both positive and negative run lengths. Therefore, unless otherwise specified, the frequency of occurrence of the positive or negative run length m in the following text will be used. and Unified representation as P m The number of occurrences P of each run length m is statistically analyzed. m This is called the run length distribution, which reflects how often each run length occurs.

[0040] In practical implementation, the run length distribution can be recorded using a run table. Each entry in the run table records a run m and the number of times that run occurs, P. m The total number of entries in the run table is M. max M max For greater than or equal to F s / (2f min integers, f min The lowest frequency of the narrowband signal detectable by the method 100 of this disclosure is a value that can be predetermined according to the detection requirements.

[0041] In step 120, the concentration of the run length is calculated based on the run length distribution.

[0042] In the present disclosure, the concentration of the run length refers to the concentration degree of the run length distribution. The higher the concentration of the run length, the more the occurrence times of a certain run length is higher than the occurrence times of other run lengths. Considering the influence of noise in the received signal, it can be understood that the sum of the occurrence times of a certain run length and its adjacent run length is much higher than the occurrence times of other run lengths. The concentration of the run length can be described by a concentration measure statistic, which can be any statistic that can reflect the concentration degree of data. After obtaining the run length distribution by statistics, the concentration measure statistic of the run length can be calculated. For example, the concentration measure statistic can be the reciprocal of a statistic reflecting the discrete degree of data. The statistic reflecting the discrete degree can be variance, mean deviation, etc. For example, for a run length distribution with the occurrence times of run length m being P m , the variance of the run length can be expressed as

[0043]

[0044] , wherein is the mean value of the run length, which can be any statistic that can reflect the concentration trend of the run length distribution, for example, it can be the arithmetic mean , wherein M = ∑ m P m represents the sum of the occurrence times of all run lengths, which is equal to the length of the IQ sampling data, i.e., the total number of sampling points of the IQ sampling data. Therefore, in some embodiments, the concentration of the run length can be measured by the following formula

[0045]

[0046] The mean deviation of the run length can be expressed as

[0047]

[0048] In other embodiments, the concentration of the run length can be measured by the following formula

[0049]

[0050] When the IQ sampling data contains a narrowband signal with high intensity, since the narrowband signal has periodicity, the run length distribution of the positive or negative numbers of the in-phase sampling data or the quadrature sampling data is basically the same, and one can be arbitrarily selected for concentration calculation.

[0051] In step 130, it is determined whether the concentration of the run length is high enough.

[0052] The concentration of the run length can be considered high enough when the concentration measure statistic of the run length is higher than a threshold. The threshold can be preset as needed.

[0053] If the variance or the reciprocal of the average difference is used as the concentration measure statistic of the run length, the concentration of the run length is considered high enough when the variance or the average difference is lower than a preset threshold.

[0054] In step 140, in response to the concentration of the run length being high enough, it is determined that a narrowband signal is detected.

[0055] If the concentration of the run length is high enough, it means that the sampling data has obvious periodicity, and thus it is determined that there is a narrowband signal in the sampling signal.

[0056] As can be seen from the above steps, the narrowband signal detection method 100 of the present disclosure analyzes the positive or negative run length distribution of the in-phase or quadrature component of the IQ sampling data by statistical analysis, and obtains the detection result according to the concentration of the run length, without complex calculation, and has the characteristic of small calculation amount.

[0057] In some embodiments, if there is a direct current signal in the IQ sampling data, the values of the in-phase sampling data or the quadrature sampling data will fluctuate up and down around the value of the direct current signal. In order to reduce the influence of the direct current signal on the run length statistics, the IQ sampling data can be removed from direct current before the positive or negative run length is counted.

[0058] In order to reduce the influence of interference, in some embodiments, the method 100 further includes step 115 before step 120. In step 115, the run length distribution is denoised, and the denoising method can be various. For example, any one or several of the following operations can be used:

[0059] (1) The occurrence times corresponding to the run lengths less than a preset run length threshold m th in the run length distribution are set to 0. That is, for the run length m, if m th is less than the preset occurrence time threshold P m , P th = 0 is set.

[0060] (2) The occurrence times corresponding to the run lengths less than a preset occurrence time threshold P th in the run length distribution are set to 0. That is, if there is a run length i, P i < P th , P i = 0 is set.

[0061] (3) In the run length distribution, the ratio of the product of the run length and its frequency to the length of the IQ sampling data is less than a preset proportional threshold λ. th The frequency of occurrence corresponding to the run length is set to 0. That is, if there exists a run length i such that i·P i / M<λ th Then set P i =0, where M is the length of the IQ sampled data.

[0062] By denoising the run length distribution, the run length, which reflects the characteristics of narrowband signals, can be further highlighted, thereby improving the accuracy of narrowband signal detection.

[0063] This disclosure also proposes a narrowband signal frequency estimation method 200 for estimating the frequency of a narrowband signal from IQ sampling data. The narrowband signal can be approximated as... Among them, f NB For the frequency of narrowband signals, For phase. For example... Figure 3 As shown, method 200 includes the following steps:

[0064] In step 210, the run length distribution is obtained by counting the positive or negative run lengths and the number of occurrences of each run length in the in-phase or orthogonal sampled data.

[0065] This step is the same as step 110 of method 100, so it will not be described again.

[0066] In step 220, the mean run length is calculated based on the run length distribution.

[0067] mean travel length This refers to any statistic that can reflect the central tendency of the run length distribution. For example, in some embodiments, the mean run length. It can be the arithmetic mean In other embodiments, the average run length It can be the mode of the run length, that is, the run length that appears most frequently.

[0068] In step 230, the frequency magnitude estimate of the narrowband signal is calculated based on the sampling rate and average run length of the IQ sampling data.

[0069] frequency of narrowband signal The following formula can be used for estimation.

[0070]

[0071] Among them, F s The sampling rate for IQ sampling data. This represents the average run length.

[0072] In step 240, the frequency sign of the narrowband signal is determined.

[0073] Here, the frequency sign refers to whether the frequency is positive or negative with respect to the sampling frequency, the frequency sign being positive means that the frequency of the narrowband signal is greater than the sampling frequency, and the frequency sign being negative means that the frequency of the narrowband signal is less than the sampling frequency. After determining the frequency sign, in combination with the frequency magnitude estimate calculated in step 230, the frequency estimate of the narrowband signal can be obtained.

[0074] In some embodiments, step 240 can be implemented by sub-steps 241a-242a, as shown in FIG. 2B. Figure 4A

[0075] In sub-step 241a, the in-phase sampling data is subtracted from the quadrature sampling data to obtain the in-phase and quadrature sampling data difference. That is, for each sampling time n, the corresponding in-phase and quadrature sampling data difference D(n) is calculated as follows: IQ (n) = I(n) - Q(n), n = 0, 1, …, N-1.

[0076] In sub-step 242a, the phase relationship between the in-phase and quadrature sampling data difference and the in-phase sampling data is compared, and the frequency sign of the narrowband signal is determined based on the phase relationship.

[0077] Specifically, if the phase of the in-phase and quadrature sampling data difference leads the phase of the in-phase sampling data, it is determined that the frequency sign of the narrowband signal is positive; if the phase of the in-phase and quadrature sampling data difference lags behind the phase of the in-phase sampling data, it is determined that the frequency sign of the narrowband signal is negative.

[0078] There are various methods that can be used to determine whether the phase of the in-phase and quadrature sampling data difference leads or lags the phase of the in-phase sampling data. For example, one implementation method is as follows:

[0079] First, the magnitudes of the in-phase sampling data and the quadrature sampling data corresponding to the tail sampling time of the positive number run in the in-phase and quadrature sampling data difference are compared, and the number of times that the in-phase sampling data is greater than the quadrature sampling data is denoted as C1, and the number of times that the quadrature sampling data is greater than the in-phase sampling data is denoted as C2.

[0080] Then, the proportions of the number of times that the in-phase sampling data is greater than or less than the quadrature sampling data are compared with a preset polarity threshold Sgn th , respectively, and whether the phase of the in-phase and quadrature sampling data difference leads the phase of the in-phase sampling data is determined according to the comparison result. If C1 / (C1+C2) is greater than the preset polarity threshold Sgn th ​If C2 / (C1+C2) is greater than a preset polarity threshold Sgn th , it is determined that the phase of the in-phase and quadrature sampling data difference lags behind the phase of the in-phase sampling data. The value of the polarity threshold Sgn th should be greater than 0.5 to avoid the above two ratios being true at the same time. In addition, if the polarity threshold Sgn th is set too high, or there is no narrowband signal in the sampling data, it is also possible that the above two formulas are not true at the same time, in which case the polarity threshold can be appropriately reduced for adjustment, or it is determined that there is no narrowband signal at this time.

[0081] In some embodiments, step 240 can also be implemented by sub-steps 241b-242b, as shown in FIG. 2B. Figure 4B

[0082] In sub-step 241b, the quadrature sampling data is subtracted from the in-phase sampling data to obtain the in-phase and quadrature sampling data difference D QI (n) = Q(n) - I(n), n = 0, 1,..., N-1.

[0083] In sub-step 242b, the phase relationship between the in-phase and quadrature sampling data difference and the quadrature sampling data is compared, and the frequency sign of the narrowband signal is determined based on the phase relationship.

[0084] Specifically, if the phase of the in-phase and quadrature sampling data difference leads the phase of the quadrature sampling data, it is determined that the frequency sign of the narrowband signal is negative; if the phase of the in-phase and quadrature sampling data difference lags behind the phase of the in-phase sampling data, it is determined that the frequency sign of the narrowband signal is positive.

[0085] Similarly, whether the phase of the in-phase and quadrature sampling data difference leads or lags behind the phase of the quadrature sampling data can be determined by the following method:

[0086] First, the sizes of the quadrature sampling data and the in-phase sampling data corresponding to the tail sampling time of the positive run in the in-phase and quadrature sampling data difference are compared, and the number of times that the quadrature sampling data is greater than the in-phase sampling data is represented as C1, and the number of times that the in-phase sampling data is greater than the quadrature sampling data is represented as C2.

[0087] Then, the proportions of the number of times that the quadrature sampling data is greater than or less than the in-phase sampling data are compared with a preset polarity threshold SGN th , and whether the phase of the in-phase and quadrature sampling data difference leads the phase of the quadrature sampling data is determined according to the comparison result. If C1 / (C1+C2) is greater than a preset polarity threshold Sgn th ​If C2 / (C1+C2) is greater than a preset polarity threshold Sgn, it is confirmed that the phase of the difference between the in-phase and quadrature sampling data lags behind the phase of the quadrature sampling data. th If C2 / (C1+C2) is greater than a preset polarity threshold Sgn, it is confirmed that the phase of the difference between the in-phase and quadrature sampling data lags behind the phase of the quadrature sampling data.

[0088] As can be seen from the above steps of the method 200, the method 200 estimates the narrowband signal frequency size by counting the positive or negative run of the in-phase or quadrature component of the IQ sampling data, and judges the frequency sign of the narrowband signal by comparing the phase relationship between the difference between the in-phase sampling data and the quadrature sampling data and the in-phase sampling data / quadrature sampling data, so as to obtain the frequency estimation value of the narrowband signal, and the method has the characteristics of small calculation amount.

[0089] Similarly to the method 100, before counting the length of the positive or negative run according to step 210, the IQ sampling data can be subjected to direct current removal, so as to reduce the influence of the direct current signal on the length of the run.

[0090] Similarly to the method 100, before step 220, a step (step 215) of denoising the distribution of the length of the run can be included, so as to highlight the length of the run reflecting the characteristics of the narrowband signal, and improve the accuracy of the narrowband signal frequency estimation. In step 215, any one or several of the following operations can be used to denoise the distribution of the length of the run:

[0091] (1) The occurrence number corresponding to the length of the run smaller than a preset length of the run threshold m th is set to 0. That is, if m th is the length of the run, P m = 0 is set.

[0092] (2) The occurrence number corresponding to the length of the run smaller than a preset occurrence number threshold P th is set to 0. That is, if there is a length of the run i, P i < P th < P i = 0 is set.

[0093] (3) The occurrence number corresponding to the length of the run whose product with the occurrence number is smaller than a preset proportion threshold λ th is set to 0. That is, if there is a length of the run i, i·P i / M < λ th < λ i = 0 is set, where M is the length of the IQ sampling data.

[0094] The present disclosure also proposes a method for eliminating a narrowband interference signal from IQ sampling data, comprising the following steps:

[0095] First, the method 100 is used to detect whether there is a narrowband interference signal in the IQ sampling data.

[0096] After detecting that there is a narrowband interference signal in the IQ sampling data, the method 200 is used to estimate the frequency of the narrowband interference signal.

[0097] Then, a notch filter with a notch center frequency equal to the frequency of the narrowband interference signal is used to filter the IQ sampling data, and a filtered signal is obtained. The bandwidth of the notch filter can be reasonably set according to the bandwidth of the narrowband interference signal. The filtered signal is the signal after the narrowband interference signal is eliminated.

[0098] In one or more exemplary embodiments, a computer program product is also provided, which includes machine executable instructions that, when executed, perform the steps of the narrowband signal detection method 100 of the present disclosure.

[0099] In one or more exemplary embodiments, a computer program product is also provided, which includes machine executable instructions that, when executed, perform the steps of the narrowband signal detection method 200 of the present disclosure.

[0100] In one or more exemplary embodiments, a wireless local area network communication device is also provided, which includes a notch filter, a processor, and a non-transitory storage medium storing computer executable instructions that can be executed by the processor to perform the steps of the narrowband interference signal elimination method of the present disclosure.

[0101] In one or more exemplary designs, the functions described in the present disclosure can be implemented in hardware, software, firmware, or any combination thereof. For example, if implemented in software or firmware, the functions can be stored as one or more instructions or codes on a computer-readable storage medium, or transmitted as one or more instructions or codes on a computer-readable storage medium.

[0102] The various components of the system disclosed herein can be implemented using discrete hardware components or integrated in one hardware component. For example, the various exemplary components described in conjunction with the present disclosure can be implemented or executed using a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or a combination thereof.

[0103] Those skilled in the art can, by reading the specification, the disclosed content and the drawings and the appended claims, understand and implement other changes to the disclosed embodiments without departing from the spirit of the claims of the present disclosure, which all fall within the scope of protection of the claims of the present disclosure. In the claims, the word "comprising" does not exclude other elements and steps, and the word "a" or "an" does not exclude a plurality. In the practical application of the present application, one part can perform the functions of multiple technical features cited in the claims. Any reference signs in the claims should not be understood as limiting the scope.

Claims

1. A method for detecting a narrowband signal from IQ sampled data, the IQ sampled data being IQ sampled data of a wireless local area network receiver, the IQ sampled data comprising in-phase sampled data and quadrature sampled data, characterized in that, The method comprises: counting the run length of positive or negative numbers in the in-phase sampling data or the quadrature sampling data and the occurrence number of each run length to obtain a run length distribution; calculating a concentration measure statistic of the run length based on the run length distribution, the concentration measure statistic of the run length being a statistic reflecting the concentration degree of the run length; judging whether the concentration measure statistic of the run length is higher than a preset threshold; and in response to the concentration measure statistic of the run length being higher than the preset threshold, determining that a narrowband signal is detected.

2. The method of claim 1, wherein, Before counting the run length of positive or negative numbers in the in-phase sampling data or the quadrature sampling data and the occurrence number of each run length, the method further comprises: performing direct current removal on the IQ sampling data.

3. The method of claim 1, wherein, The concentration measure statistic of the run length is the reciprocal of the variance of the run length or the reciprocal of the average difference of the run length.

4. The method of claim 1, wherein, Before calculating the concentration measure statistic of the run length based on the run length distribution, the method further comprises: performing any one or several of the following operations on the run length distribution: (1) setting the occurrence number corresponding to the run length smaller than a preset run length threshold in the run length distribution to 0; (2) setting the occurrence number smaller than a preset occurrence number threshold in the run length distribution to 0; (3) setting the occurrence number corresponding to the run length whose product with the occurrence number is smaller than a preset proportion threshold in the run length distribution to 0.

5. The method of claim 1, wherein, The narrowband signal is a Bluetooth signal.

6. A method of narrowband signal frequency estimation for estimating the frequency of a narrowband signal from IQ sample data, the IQ sample data being IQ sample data of a wireless local area network receiver, the IQ sample data comprising in-phase sample data and quadrature sample data, characterized in that, The method comprises: detecting whether there is a narrowband signal in the IQ sampling data using the method of any one of claims 1-5; in response to detecting a narrowband signal, performing the following steps: calculating a mean value of the run length based on the run length distribution; calculating a frequency size estimation value of the narrowband signal based on the sampling rate of the IQ sampling data and the mean value of the run length; and determining the frequency sign of the narrowband signal using any one of the following methods: (1) subtracting the quadrature sampling data from the in-phase sampling data to obtain an in-phase and quadrature sampling data difference; comparing the phase relationship between the in-phase and quadrature sampling data difference and the in-phase sampling data; if the phase of the in-phase and quadrature sampling data difference leads the phase of the in-phase sampling data, determining that the frequency sign of the narrowband signal is positive; if the phase of the in-phase and quadrature sampling data difference lags the phase of the in-phase sampling data, determining that the frequency sign of the narrowband signal is negative; (2) subtracting the in-phase sampling data from the quadrature sampling data to obtain a quadrature and in-phase sampling data difference; comparing the phase relationship between the quadrature and in-phase sampling data difference and the quadrature sampling data; if the phase of the quadrature and in-phase sampling data difference leads the phase of the quadrature sampling data, determining that the frequency sign of the narrowband signal is negative; if the phase of the quadrature and in-phase sampling data difference lags the phase of the in-phase sampling data, determining that the frequency sign of the narrowband signal is positive.

7. The method of claim 6, wherein, The comparison of the phase relationship between the in-phase and quadrature sample data difference and the in-phase sample data comprises: comparing the magnitudes of the in-phase sample data and the quadrature sample data corresponding to the tail sampling time of the positive run in the in-phase and quadrature sample data difference, wherein the number of times that the in-phase sample data is greater than the quadrature sample data is denoted as C1, and the number of times that the quadrature sample data is greater than the in-phase sample data is denoted as C2; if C1 / (C1+C2) is greater than a preset polarity threshold, it is determined that the phase of the in-phase and quadrature sample data difference leads the phase of the in-phase sample data; if C2 / (C1+C2) is greater than a preset polarity threshold, it is determined that the phase of the in-phase and quadrature sample data difference lags the phase of the in-phase sample data.

8. The method of claim 6, wherein, The comparison of the phase relationship between the in-phase and quadrature sample data difference and the in-phase sample data comprises: comparing the magnitudes of the in-phase sample data and the quadrature sample data corresponding to the tail sampling time of the positive run in the in-phase and quadrature sample data difference, wherein the number of times that the in-phase sample data is greater than the quadrature sample data is denoted as C1, and the number of times that the quadrature sample data is greater than the in-phase sample data is denoted as C2; if C1 / (C1+C2) is greater than a preset polarity threshold, it is determined that the phase of the in-phase and quadrature sample data difference leads the phase of the in-phase sample data; if C2 / (C1+C2) is greater than a preset polarity threshold, it is determined that the phase of the in-phase and quadrature sample data difference lags the phase of the in-phase sample data.

9. The method of claim 6, wherein, Before calculating the mean run length based on the run length distribution, the method further comprises: performing any one or several of the following operations on the run length distribution: (1) setting the occurrence number corresponding to the run length smaller than a preset run length threshold in the run length distribution to 0; (2) setting the occurrence number smaller than a preset occurrence number threshold in the run length distribution to 0; (3) setting the occurrence number corresponding to the run length whose product with the occurrence number is smaller than a preset proportion threshold in the run length distribution to 0.

10. A method for narrowband interference signal cancellation, used for canceling a narrowband interference signal in IQ sampling data, the IQ sampling data comprising in-phase sampling data and quadrature sampling data, characterized in that, The method comprises: obtaining the frequency size estimate and the frequency sign of the narrowband interference signal using the method of any one of claims 6 to 9, thereby obtaining the frequency of the narrowband interference signal; and filtering the IQ sample data using a notch filter with a notch center frequency equal to the frequency of the narrowband interference signal to obtain a filtered signal.

11. A computer program product comprising machine executable instructions which, when executed, perform the method of any one of claims 1 to 5.

12. A computer program product comprising machine executable instructions which, when executed, perform the method of any one of claims 6 to 9.

13. A wireless local area network communication device, characterized by The wireless local area network communication device comprises a notch filter, a processor, and a non-transitory storage medium storing computer executable instructions which can be executed by the processor to perform the method of claim 10. The wireless local area network communication device comprises a notch filter, a processor, and a non-transitory storage medium storing computer executable instructions which can be executed by the processor to perform the method of claim 10.

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