Modulation mode identification method and device based on comprehensive characteristics of wireless signals

Abstract

The invention belongs to the technical field of signal processing, and provides a modulation mode identification method and device based on wireless signal comprehensive characteristics, and the method comprises the steps: obtaining the comprehensive characteristics of a target from a wireless signal, the comprehensive characteristics comprising at least one of a time domain characteristic, a frequency domain characteristic and a time-frequency domain characteristic; under the condition that the comprehensive feature meets a feature judgment threshold and a signal-to-noise ratio threshold corresponding to the target modulation type, determining the target modulation type as a modulation mode identification result; wherein the candidate modulation type comprises at least one of 2ASK, 2 / 4 / 8FSK, MSK, 2 / 4 / 8PSK, OQPSK, Pi / 4DQPSK and 16QAM (Quadrature Amplitude Modulation). According to the method provided by the invention, the modulation mode identification accuracy of the wireless signal is improved.

Description

Technical Field

[0001] The present invention relates to the field of signal processing technology, and in particular to a modulation mode identification method and device based on comprehensive characteristics of wireless signals. Background Art

[0002] With the rapid development of modern communication technology, wireless communication systems are widely used in military, civil and industrial control and other fields. Since the modulation method directly determines the transmission characteristics of the signal, the accurate identification of the modulation method of unknown signals has become an important research topic in the fields of wireless signal monitoring, spectrum regulation and non-cooperative communication.

[0003] In practical applications, the modulation methods of wireless signals include linear modulation (such as AM, FM), nonlinear modulation (such as PSK, QAM) and composite modulation (such as MSK+AM, 2FSK+FM). With the development of high-order modulation technology, the spectrum utilization of signals has been significantly improved, but it also brings higher challenges to the identification of modulation methods in low signal-to-noise ratio thresholds, complex interference and unknown environments.

[0004] In the related technology, a single signal feature is mainly used to identify and extract the signal modulation mode, and the recognition condition is only related to the signal feature. It is difficult to maintain high recognition accuracy in complex environments (different signal-to-noise ratio threshold requirements), resulting in a decrease in the accuracy of identifying the modulation mode of the wireless signal. Summary of the invention

[0005] The present invention provides a modulation mode identification method and device based on the comprehensive characteristics of wireless signals, so as to solve the defect that the prior art uses a single signal feature to identify and extract the signal modulation mode, and the identification condition is only related to the signal feature, which makes it difficult to maintain high recognition accuracy in a complex environment, resulting in a decrease in the accuracy of modulation mode identification of wireless signals, thereby improving the modulation mode identification accuracy of wireless signals.

[0006] The present invention provides a modulation mode identification method based on comprehensive characteristics of wireless signals, comprising: Acquire a comprehensive feature of the target from the wireless signal, wherein the comprehensive feature includes at least one of a time domain feature, a frequency domain feature, and a time-frequency domain feature; The wireless signal is identified based on the candidate modulation types, and when the comprehensive characteristics meet the feature decision threshold and signal-to-noise ratio threshold corresponding to the target modulation type, the target modulation type is determined as the modulation mode identification result; wherein the candidate modulation types include at least one of 2ASK, 2 / 4 / 8FSK, MSK, 2 / 4 / 8PSK, OQPSK, π / 4DQPSK and 16QAM; the target modulation type belongs to the candidate modulation types.

[0007] According to a modulation mode identification method based on comprehensive characteristics of wireless signals provided by the present invention, the time domain characteristics include envelope smoothness, and the envelope smoothness is used to distinguish between amplitude modulation signals, phase modulation signals and frequency modulation signals; The frequency domain features include the number of peaks and the degree of flatness of the normalized power spectrum, and the frequency domain features are used to characterize the frequency characteristics of the wireless signal; The time-frequency domain feature includes the flatness of the modulus of the normalized instantaneous frequency, and the time-frequency domain feature is used to identify the state frequency change characteristics of the wireless signal.

[0008] According to a modulation mode identification method based on comprehensive characteristics of wireless signals provided by the present invention, the comprehensive characteristics include at least two of time domain characteristics, frequency domain characteristics and time-frequency domain characteristics; The identifying of the wireless signal based on the candidate modulation type, and determining that the target modulation type is a modulation mode identification result when the comprehensive feature satisfies the feature decision threshold and the signal-to-noise ratio threshold corresponding to the target modulation type, includes: The wireless signal is identified in sequence according to the target order based on the candidate modulation types, and when the comprehensive feature satisfies the feature decision threshold and signal-to-noise ratio threshold corresponding to the target modulation type, the first appearing target modulation type is determined as the modulation mode identification result; wherein, the target order is determined based on the sequence of time domain features, frequency domain features and time-frequency domain features.

[0009] According to a modulation mode identification method based on comprehensive characteristics of wireless signals provided by the present invention, the comprehensive characteristics include time domain characteristics; the time domain characteristics include envelope smoothness; When the comprehensive feature satisfies the feature decision threshold and the signal-to-noise ratio threshold corresponding to the target modulation type, determining that the target modulation type is a modulation mode identification result includes: When the feature decision threshold corresponding to the time domain feature is greater than 1.27 and the signal-to-noise ratio threshold corresponding to the time domain feature is greater than or equal to 5 dB, determining that the modulation mode recognition result is 2ASK; When the feature decision threshold corresponding to the time domain feature is between 1.12 and 1.27, and the signal-to-noise ratio threshold corresponding to the time domain feature is greater than or equal to 12 dB, determining that the modulation mode identification result is 2PSK or 16QAM; When the feature decision threshold corresponding to the time domain feature is between 1.03 and 1.12, and the signal-to-noise ratio threshold corresponding to the time domain feature is greater than or equal to 12 dB, determining that the modulation mode identification result is 4PSK, 8PSK, π / 4DQPSK or 4OQPSK; When the feature decision threshold corresponding to the time domain feature is less than 1.03 and the signal-to-noise ratio threshold corresponding to the time domain feature is greater than or equal to 15 dB, determine that the modulation mode identification result is CW, 2MSK or 2 / 4 / 8FSK; Alternatively, when the feature decision threshold corresponding to the time domain feature is less than 1.03 and the signal-to-noise ratio threshold corresponding to the time domain feature is greater than or equal to 12dB, the modulation mode identification result is determined to be 2MSK or 2 / 4 / 8FSK.

[0010] According to a modulation mode identification method based on comprehensive characteristics of wireless signals provided by the present invention, the comprehensive characteristics also include frequency domain characteristics; the frequency domain characteristics include the number of peaks of the normalized power spectrum; In the case where the comprehensive feature satisfies the feature decision threshold and the signal-to-noise ratio threshold corresponding to the target modulation type, determining that the target modulation type is a modulation mode identification result also includes: When the 1st, 2nd, 4th and 8th power spectra of the wireless signal converge and the number of peaks is 1, determining that the modulation mode identification result is CW; When the 1st, 2nd, 4th and 8th power spectra of the wireless signal converge, the signal-to-noise ratio threshold corresponding to the 4th power spectrum is greater than or equal to 0 dB, the signal-to-noise ratio threshold corresponding to the 8th power spectrum is greater than or equal to 7 dB, and the number of peaks is 1, it is determined that the modulation mode identification result is 2ASK; When the 2nd, 4th and 8th power spectra of the wireless signal converge, the signal-to-noise ratio threshold corresponding to the 4th power spectrum is greater than or equal to 1 dB, the signal-to-noise ratio threshold corresponding to the 8th power spectrum is greater than or equal to 8.5 dB, and the number of peaks is 1, it is determined that the modulation mode identification result is 2PSK; When the fourth power spectrum of the wireless signal converges, the eighth power spectrum partially converges, the fourth power power spectrum corresponding to the signal-to-noise ratio threshold is greater than or equal to 4 dB, and the number of peaks is 1, determine that the modulation mode identification result is 4PSK or 4OQPSK; When the 2nd, 4th and 8th power spectra of the wireless signal converge, the signal-to-noise ratio threshold corresponding to the 2nd power spectrum is greater than or equal to 1dB, the signal-to-noise ratio threshold corresponding to the 4th power spectrum is greater than or equal to 7dB, the signal-to-noise ratio threshold corresponding to the 8th power spectrum is greater than or equal to 13.5dB, and the number of peaks is 2, it is determined that the modulation mode identification result is 2MSK.

[0011] According to a modulation mode identification method based on comprehensive characteristics of wireless signals provided by the present invention, the frequency domain characteristics also include a flatness; In the case where the comprehensive feature satisfies the feature decision threshold and the signal-to-noise ratio threshold corresponding to the target modulation type, determining that the target modulation type is a modulation mode identification result further includes: When the characteristic decision threshold corresponding to the power spectrum of the wireless signal to the power of 1 is greater than 0.3, and the corresponding signal-to-noise ratio threshold is greater than -6dB, the characteristic decision threshold corresponding to the power spectrum of the wireless signal to the power of 2 is greater than 0.32, and the corresponding signal-to-noise ratio threshold is greater than -6dB, and the characteristic decision threshold corresponding to the power spectrum of the wireless signal to the power of 4 is greater than 0.3, and the corresponding signal-to-noise ratio threshold is greater than -6dB, it is determined that the modulation mode identification result is CW; When the characteristic decision threshold corresponding to the power spectrum of the wireless signal to the power of 1 is greater than 0.3, the corresponding signal-to-noise ratio threshold is greater than -6 dB, the characteristic decision threshold corresponding to the power spectrum of the wireless signal to the power of 2 is greater than 0.32, the corresponding signal-to-noise ratio threshold is greater than 1 dB, and the characteristic decision threshold corresponding to the power spectrum of the wireless signal to the power of 4 is greater than 0.27, and the corresponding signal-to-noise ratio threshold is greater than 3 dB, the modulation mode identification result is determined to be 2ASK; When the characteristic decision threshold corresponding to the power spectrum of the wireless signal to the power of 1 is less than 0.3, and the corresponding signal-to-noise ratio threshold is greater than -6 dB, the characteristic decision threshold corresponding to the power spectrum of the wireless signal to the power of 2 is greater than 0.32, and the corresponding signal-to-noise ratio threshold is greater than 1 dB, and the characteristic decision threshold corresponding to the power spectrum of the wireless signal to the power of 4 is greater than 0.27, and the corresponding signal-to-noise ratio threshold is greater than 3 dB, it is determined that the modulation mode identification result is 2PSK; The feature decision threshold corresponding to the 1st power spectrum of the wireless signal is less than 0.3, and the corresponding signal-to-noise ratio threshold is greater than -6dB, the feature decision threshold corresponding to the 2nd power spectrum is less than 0.1, and the corresponding signal-to-noise ratio threshold is greater than or equal to -6dB, and the 4th power spectrum meets one of the following conditions: When the characteristic decision threshold of the fourth-power power spectrum is between 0.1 and 0.4 and the corresponding signal-to-noise ratio threshold is greater than 3 dB, determining that the modulation mode identification result is 4PSK or π / 4DQPSK; When the characteristic decision threshold of the power spectrum of the fourth power is between 0.25 and 0.4 and the corresponding signal-to-noise ratio threshold is greater than 6 dB, the modulation mode identification result is determined to be 4OQPSK; When the characteristic decision threshold of the power spectrum of the fourth power is less than 0.05 and the corresponding signal-to-noise ratio threshold is greater than or equal to -6dB, the modulation mode recognition result is determined to be 8PSK; The feature decision threshold corresponding to the 1st power spectrum of the wireless signal is less than 0.3, and the corresponding signal-to-noise ratio threshold is greater than -6dB, the feature decision threshold corresponding to the 2nd power spectrum is less than 0.3, and the corresponding signal-to-noise ratio threshold is greater than or equal to -3dB, and the 4th power spectrum meets one of the following conditions: When the characteristic decision threshold of the fourth power spectrum is between 0.15 and 0.35 and the corresponding signal-to-noise ratio threshold is greater than 12 dB, the modulation mode recognition result is determined to be 2MSK; When the characteristic decision threshold of the fourth power spectrum is less than 0.05 and the corresponding signal-to-noise ratio threshold is greater than -6dB, the modulation mode identification result is determined to be 8FSK.

[0012] According to a modulation mode identification method based on comprehensive characteristics of wireless signals provided by the present invention, the comprehensive characteristics also include time-frequency domain characteristics; the time-frequency domain characteristics include the flatness of the modulus of the normalized instantaneous frequency; In the case where the comprehensive feature satisfies the feature decision threshold and the signal-to-noise ratio threshold corresponding to the target modulation type, determining that the target modulation type is a modulation mode identification result also includes: When the characteristic decision threshold corresponding to the flatness of the mode is between 1.8 and 2.5, and the corresponding signal-to-noise ratio threshold is greater than or equal to 10 dB, determining that the modulation mode identification result is π / 4DQPSK; When the characteristic decision threshold corresponding to the flatness of the mode is greater than 1.9 and the corresponding signal-to-noise ratio threshold is greater than or equal to 8 dB, determining that the modulation mode identification result is 2ASK, 2 / 4 / 8PSK or 16QAM; When the characteristic decision threshold corresponding to the flatness of the mode is between 1.32 and 1.95, and the corresponding signal-to-noise ratio threshold is greater than or equal to 12 dB, determining that the modulation mode identification result is 4OQPSK or 4 / 8FSK; When the characteristic decision threshold corresponding to the flatness of the mode is between 1.05 and 1.32, and the corresponding signal-to-noise ratio threshold is greater than or equal to 20 dB, determining that the modulation mode identification result is 2FSK or 2MSK; When the characteristic decision threshold corresponding to the flatness of the mode is less than 1.05 and the corresponding signal-to-noise ratio threshold is greater than or equal to 13 dB, it is determined that the modulation mode identification result is CW.

[0013] The present invention also provides a modulation mode identification device based on comprehensive characteristics of wireless signals, characterized in that it includes: A feature acquisition module, used to acquire a comprehensive feature from the wireless signal, wherein the comprehensive feature includes at least one of a time domain feature, a frequency domain feature, and a time-frequency domain feature; An identification module is used to identify the wireless signal based on candidate modulation types, and determine that the target modulation type is a modulation mode identification result when the comprehensive characteristics meet the feature decision threshold and signal-to-noise ratio threshold corresponding to the target modulation type; wherein the candidate modulation types include at least one of 2ASK, 2 / 4 / 8FSK, MSK, 2 / 4 / 8PSK, OQPSK, π / 4DQPSK and 16QAM; and the target modulation type belongs to the candidate modulation types.

[0014] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, a modulation mode identification method based on comprehensive characteristics of a wireless signal as described in any one of the above is implemented.

[0015] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the method for identifying the modulation mode of the comprehensive characteristics of the wireless signal as described in any one of the above is implemented.

[0016] The present invention also provides a computer program product, including a computer program, which, when executed by a processor, implements the modulation mode identification method based on the comprehensive characteristics of a wireless signal as described in any one of the above.

[0017] The modulation mode identification method and device based on the comprehensive characteristics of wireless signals provided by the present invention obtain comprehensive characteristics from wireless signals, and identify the wireless signals based on candidate modulation types. When the comprehensive characteristics meet the characteristic decision threshold and signal-to-noise ratio threshold corresponding to the target modulation type, the target modulation type is determined as the modulation mode identification result, thereby improving the modulation mode identification accuracy of the wireless signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are 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.

[0019] Figure 1 This is one of the flow charts of the modulation mode identification method based on the comprehensive characteristics of wireless signals provided by the present invention.

[0020] Figure 2 This is the second flow chart of the modulation mode identification method based on the comprehensive characteristics of wireless signals provided by the present invention.

[0021] Figure 3It is a structural schematic diagram of a modulation mode identification device based on comprehensive characteristics of wireless signals provided by the present invention.

[0022] Figure 4 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Combine the following Figure 1-Figure 3 The present invention describes a modulation mode identification method and device based on comprehensive characteristics of wireless signals.

[0025] Figure 1 This is one of the flow charts of the modulation mode identification method based on the comprehensive characteristics of wireless signals provided by the present invention, such as Figure 1 As shown, the method comprises the following steps: Step 110: Acquire comprehensive features of the target from the wireless signal, where the comprehensive features include at least one of time domain features, frequency domain features, and time-frequency domain features.

[0026] In this step, the target in the wireless signal includes time-domain baseband in-phase and quadrature IQ data of the wireless signal.

[0027] In this step, the time domain features include changes in amplitude and phase, such as high-order cumulants and statistical features of instantaneous amplitude.

[0028] In this embodiment, the time domain characteristics include the flatness of the signal envelope; the signal envelope can stably reflect the characteristics of different modulation signals, and the flatness of the signal envelope can be used. QUR for identification.

[0029] In this embodiment, for modulation signals such as 2ASK, 2FSK, 4FSK, 8FSK, MSK, 2PSK, 4PSK, 8PSK, OQPSK, π / 4DQPSK and 16QAM, the 2ASK and 16QAM with amplitude modulation are QUR The value should be larger than 2PSK, 4PSK, 8PSK, OQPSK and π / 4DQPSK for phase modulation, 2FSK, 4FSK, 8FSK and MSK for frequency modulation. QUR The value is smaller than the corresponding value of the above modulation signal QUR value.

[0030] In this embodiment, the frequency domain features include the number of peaks of normalized power spectra of different powers (eg, 1st, 2nd, 4th, or 8th) of the wireless signal and the flatness of the normalized power spectrum.

[0031] Specifically, the method for obtaining the number of peaks of the normalized power spectrum includes: firstly raising the wireless signal to the power of p=1, 2, 4, 8, obtaining the linear power spectrum and then normalizing it based on the maximum value, and calculating the number of peaks of the normalized power spectrum.

[0032] For 2ASK, 2 / 4 / 8FSK, MSK, 2 / 4 / 8PSK, OQPSK, π / 4DQPSK and 16QAM, the number of peaks of the corresponding normalized power spectrum includes 1, 2, 1+2 (1 main peak + two symbol rate spectrum lines on both sides), 4 and 8. In this embodiment, the position where the peak may exist is first found, and at the same time, it is also necessary to consider how to weaken the non-single peak caused by spectrum leakage (the point near the peak is close to the main peak).

[0033] In this embodiment, the flatness kur of the normalized power spectrum corresponding to the signal after p=1, 2, 4, and 8 powers is calculated.

[0034] Specifically, the linear power spectrum of the signal is first normalized to the maximum value, smoothed and then normalized, and then the ratio of the 8th order central moment of the power spectrum to the square of the 4th order origin moment of the power spectrum is calculated and then divided by the signal length to obtain the above kur.

[0035] In this embodiment, the time-frequency domain features include the flatness of the modulus of the normalized instantaneous frequency of the signal; the instantaneous frequency represents the relationship between time and frequency, and the instantaneous frequency can be obtained by phase difference; the instantaneous frequency is then normalized, for example, the instantaneous frequency is mapped to the interval [0,1] to obtain the normalized instantaneous frequency; then the modulus of the normalized instantaneous frequency is calculated, and its flatness is evaluated to obtain the flatness of the modulus of the normalized instantaneous frequency .

[0036] Step 120: Identify the wireless signal based on the candidate modulation types, and determine the target modulation type as the modulation mode identification result when the comprehensive characteristics meet the feature decision threshold and signal-to-noise ratio threshold corresponding to the target modulation type; wherein the candidate modulation types include at least one of 2ASK, 2 / 4 / 8FSK, MSK, 2 / 4 / 8PSK, OQPSK, π / 4DQPSK and 16QAM; the target modulation type belongs to the candidate modulation type.

[0037] In this step, the feature decision threshold and signal-to-noise ratio threshold can be obtained through simulation experiments; for example, the feature decision threshold and signal-to-noise ratio threshold corresponding to the comprehensive feature are recorded using the awgn channel as the simulated channel model to obtain the corresponding decision interval; for example, the comprehensive feature includes the time domain feature, and the time domain feature is the flatness of the signal envelope. QUR , determined by simulation: when QUR When the corresponding feature decision threshold is greater than 1.27 and the required signal-to-noise ratio threshold SNR is greater than or equal to 5 dB, the modulation mode recognition result of the wireless signal is determined to be 2ASK; QUR Corresponding to different feature decision thresholds and signal-to-noise ratio thresholds, the wireless signal corresponds to different modulation modes.

[0038] For example, the comprehensive features include frequency domain features, and the frequency domain features include the number of peaks peakNum of the normalized power spectrum. Through simulation, it is determined that: the 2nd, 4th, and 8th power spectra of the wireless signal are all converged, the signal-to-noise ratio of the 2nd power spectrum has no effect on the signal, the SNR of the 4th power spectrum is ≥0dB, the SNR of the 8th power spectrum is ≥7dB, and the number of peaks of each power spectrum is always 1, then the modulation mode identification result of the wireless signal is determined to be 2PSK; peakNum corresponds to different feature decision thresholds and signal-to-noise ratio thresholds, then the wireless signal corresponds to different modulation modes.

[0039] In this embodiment, the frequency domain features also include the flatness kur of the normalized power spectrum. Through simulation, it is determined that: the kur of the first-power power spectrum of the wireless signal is greater than 0.3, and the signal-to-noise ratio threshold is greater than or equal to -6dB, the kur of the second-power power spectrum is greater than 0.32, and the signal-to-noise ratio threshold is greater than or equal to -6dB, and the kur of the fourth-power power spectrum is greater than 0.3, and the signal-to-noise ratio threshold is greater than or equal to -6dB, then the modulation mode identification result of the wireless signal is determined to be CW; kur corresponds to different feature decision thresholds and signal-to-noise ratio thresholds, then the wireless signal corresponds to different modulation modes.

[0040] For example, the comprehensive features include time-frequency domain features, and the time domain feature is the flatness of the modulus of the normalized instantaneous frequency ftNormAbsR. Through simulation, it is determined that: the decision interval corresponding to ftNormAbsR is between 1.8 and 2.5, and the required signal-to-noise ratio SNR is greater than or equal to 10dB, then the modulation mode identification result of the wireless signal is determined to be π / 4DQPSK; ftNormAbsR corresponds to different feature decision thresholds and signal-to-noise ratio thresholds, then the wireless signal corresponds to different modulation modes.

[0041] In this embodiment, for an unknown input signal, each candidate modulation type (2ASK, 2FSK, 4FSK, 8FSK, MSK, 2PSK, 4PSK, 8PSK, OQPSK, π / 4DQPSK, 16QAM) is first traversed according to the extracted comprehensive features. If, when traversing to a certain modulation mode, the parameter value corresponding to the comprehensive feature simultaneously satisfies the decision threshold and signal-to-noise ratio threshold of the corresponding feature of the current candidate modulation type, the current input signal can be considered to belong to this modulation mode, thereby completing the blind identification of the modulation mode for the signal of the unknown modulation type.

[0042] In this embodiment, for the signal processing parameters involved in the modulation mode identification process, the number of symbols contained in the signal to be identified is set to ≥512, the oversampling multiple is ≥4, the number of FFT points is ≥2048 points, and multiple gears can be set, such as 2048, 4096, and 8192 points, to ensure the recognition rate under low signal-to-noise ratio; in this embodiment, the recognition rates obtained by different classification methods are different, and the above classification method can be continuously adjusted, and the classification threshold can also be fine-tuned.

[0043] In this embodiment, the awgn channel is used as a simulated channel model to record the feature decision threshold and signal-to-noise ratio threshold corresponding to the comprehensive feature, and the corresponding simulation parameters and results include: (1) Simulation conditions: set 12 signals, including CW, 2ASK, 2PSK, 4PSK, 8PSK, 4OQPSK, π / 4DQPSK, 16QAM, 2FSK, 4FSK, 8FSK and 2MSK (2 / 4 / 8FSK / MSK are signals obtained by linear frequency modulation), among which CW is used for comparison reference; set the signal-to-noise ratio from -10 dB to 35 dB, in steps of 0.01 dB, the symbol rate to 8192 Hz, the number of symbols to 1024 / 512 / 256 / 128, and the oversampling factor to 4.

[0044] (2) Using the above strategy, simulation results are shown in Table 1: Table 1. Classification data table with oversampling factor of 4 and number of symbols of 1024 / 512 / 256 / 128

[0045] It should be noted that the percentages in the above table are the number of successful classifications / the number of test classifications × 100%.

[0046] In this embodiment, in order to reflect the randomness of the signal, for each signal-to-noise ratio, the random value interval of the IQ amplitude is [10, 100], the IQ phase deviation is [0, 2π], the IQ frequency deviation is [-500, 500] Hz, the 2 / 4 / 8FSK modulation index is [0.2, 0.8], the shaping filter roll-off coefficient is [0.2, 0.8] (step 0.1, 2 / 4 / 8FSK is a root raised cosine filter, MSK is a built-in rectangular pulse, and other signals are randomly generated by the raised cosine filter within the corresponding range), etc., and the message signal is also randomly generated; in this embodiment, the threshold thr when calculating peakNum is set to 0.5, the index difference threshold thrDiff is set to 2, and the number of smoothing points L used when calculating kur is 3 points.

[0047] The modulation mode identification method based on the comprehensive characteristics of wireless signals provided in the embodiment of the present invention obtains the comprehensive characteristics of the target from the wireless signal, and identifies the wireless signal based on the candidate modulation type. When the comprehensive characteristics meet the characteristic decision threshold and signal-to-noise ratio threshold corresponding to the target modulation type, the target modulation type is determined as the modulation mode identification result, thereby improving the modulation mode identification accuracy of the wireless signal.

[0048] In some embodiments, the time domain feature includes envelope smoothness, and the envelope smoothness is used to distinguish between amplitude modulated signals, phase modulated signals, and frequency modulated signals; In this embodiment, it is assumed that the baseband IQ signal is expressed in complex form as y, and the signal envelope is Obtained by taking the complex number y modulo; calculation Variance , the mean is , that is: ; Remove the constant term from the above formula and get the following formula: ; in, QUR That is, it is the characteristic parameter of the flatness of the signal envelope, which is the mean of the square of the envelope divided by the square of the upper envelope mean. QUR The minimum value of is 1; R The smaller the value is, the smoother the signal envelope distribution is, and the more likely it is a non-amplitude modulation signal. QUR The larger the value is, the steeper the signal envelope distribution is, and the more likely it is an amplitude modulation signal.

[0049] Frequency domain features include the number of peaks and the degree of flatness of the normalized power spectrum. Frequency domain features are used to characterize the frequency characteristics of wireless signals.

[0050] In this embodiment, the following steps are specifically used to obtain the number and positions of the peaks of the normalized power spectrum: (1) First, the value of the normalized power spectrum is smoothed at L points (smoothing is performed under the linear power spectrum), where L is configurable.

[0051] (2) Set the threshold value, denoted as thr, and compare it point by point with the value of the smoothed normalized power spectrum. When the first point greater than or equal to the threshold appears, it is recorded as the first left index, and this index point is also recorded as the first right index. Continue to compare the threshold until a point that does not meet the threshold is found. Then record the index of the last point that meets the threshold. Update the value of the first right index recorded previously to the index of the last point that meets the threshold. These two index values ​​are the first left and right index pair. Then continue to repeat the above operation to find the second, third, and other left and right index pairs until all points are compared. A total of N index pairs are obtained, and the number of possible peaks is N.

[0052] (3) Find the index of the maximum value in each index pair and set the index difference threshold thrDiff between the maximum values ​​to eliminate false peaks, including the following situations: (4) If N = 1, the peak number peakNum = 1.

[0053] (5) If N=2, the result of subtracting the previous index value from the next index value is greater than thrDiff, then the peak number peakNum=2; otherwise, the peak number peakNum=1.

[0054] (6) If N=3, the peak value corresponding to the middle index value minus the peak values ​​corresponding to the index values ​​on both sides is greater than 0, and the result of twice the middle index value minus the sum of the previous and next indexes is less than or equal to thrDiff, then the peak values ​​on both sides are considered to be symbol rate spectrum lines and are false peaks, and the peak number peakNum=1, otherwise the peak number peakNum=3.

[0055] (7) If N = 4 or 8, subtract the previous index from the next index to obtain N-1 index differences, calculate the mean of the index differences, subtract the mean from each index difference, and then take the absolute value to obtain N-1 absolute values. Compare these N-1 absolute values ​​with thrDiff in turn. When the absolute value is less than or equal to thrDiff, the number of peaks is increased by 1. If the last number of peaks is N-1, it is considered that the gaps between N adjacent peaks are basically the same, and the number of peaks peakNum=N. If the last number of peaks is not N-1, it is considered that the gaps between N adjacent peaks are inconsistent, and the number of peaks listed above is not satisfied, and the number of peaks peakNum=0.

[0056] (8) In other cases, the peak number peakNum=0.

[0057] In this embodiment, when calculating the flatness kur of the normalized power spectrum, the linear power spectrum of the signal is first normalized to the maximum value, smoothed and then normalized, and then the ratio of the 8th order central moment of the power spectrum to the square of the 4th order origin moment of the power spectrum is calculated and divided by the signal length.

[0058] For example, suppose the power spectrum to be input is , and its k-th order central moment is , the k-order origin moment is , that is: ; in, It can be the power spectrum of the signal after p=1, 2, 4, 8, and len is Length; is the mean of the fourth power of the envelope, is the square of the envelope mean.

[0059] The time-frequency domain features include the flatness of the modulus of the normalized instantaneous frequency, and the time-frequency domain features are used to identify the state frequency change characteristics of the wireless signal.

[0060] In this embodiment, the time-frequency domain features are obtained by the following steps: Assuming that an IQ complex signal of N points with a sampling rate of fs is received, the arc tangent of the signal in the time domain of the N-point signal is calculated, and a discontinuous phase sequence ang in the range of [-π, +π] and the difference between the previous and next phases are calculated. ; Among them, the original process of solving the instantaneous frequency involves two differential (post-subtraction) operations involving unwinding and differentiation. When applied to engineering, it can be simplified to one operation. The instantaneous frequency corresponding to the IQ complex signal is It is expressed as follows: ; in, ; , and satisfy the following formula: ; Above That is the instantaneous frequency, which is normalized by dividing it by 0.5 times the sampling rate and then taking the modulus value, which is expressed by the following formula: ; in, That is the modulus of the normalized instantaneous frequency of the signal, which ranges from 0 to 1; finally Substituting into the above calculation method of the degree of smoothness, the degree of smoothness of the normalized instantaneous frequency can be obtained, which is recorded as .

[0061] The modulation mode identification method based on the comprehensive characteristics of wireless signals provided by the embodiment of the present invention sets the time domain characteristics including envelope smoothness to distinguish between amplitude modulation signals, phase modulation signals and frequency modulation signals; sets the frequency domain characteristics including the number of peaks and the flatness of the normalized power spectrum to characterize the frequency characteristics of the wireless signal, and enhances the ability to characterize the frequency characteristics of complex signals through the combination of the number of peaks and the flatness of the normalized power spectrum; sets the time-frequency domain characteristics including the flatness of the modulus of the normalized instantaneous frequency to identify the dynamic frequency change characteristics of the wireless signal, effectively making up for the shortcomings of traditional time-frequency diagram analysis in dynamic frequency change identification.

[0062] In some embodiments, the comprehensive features include at least two of time domain features, frequency domain features, and time-frequency domain features; the wireless signal is identified based on the candidate modulation types, and when the comprehensive features meet the feature decision threshold and signal-to-noise ratio threshold corresponding to the target modulation type, the target modulation type is determined to be the modulation mode identification result, including: based on the candidate modulation types, the wireless signal is identified in sequence according to the target order, and when the comprehensive features meet the feature decision threshold and signal-to-noise ratio threshold corresponding to the target modulation type, the first occurrence of the target modulation type is determined as the modulation mode identification result; wherein the target order is determined based on the order of time domain features, frequency domain features, and time-frequency domain features.

[0063] In this embodiment, when using multiple signal characteristics to determine the modulation mode, feature parameters with a low signal-to-noise ratio that can distinguish the modulation mode are preferentially selected, and feature parameters with a high signal-to-noise ratio that can distinguish the modulation mode are secondly selected. That is, using the above order, signals that are easy to distinguish can be determined first, and then signals that are difficult to distinguish can be determined.

[0064] In this embodiment, when the modulation mode is identified by using the number of peaks and their flatness of the multi-power spectrum of the signal, the signal modulation mode can be determined from the 1st power one by one, and the result can be output immediately after the modulation mode is determined.

[0065] In this embodiment, when the comprehensive features include time domain features and frequency domain features, the target order is to screen the modulation modes in the order of time domain features and frequency domain features; when the comprehensive features include time domain features, frequency domain features and time-frequency domain features, the target order is to screen the modulation modes in the order of time domain features, frequency domain features and time-frequency domain features.

[0066] Specifically, for an unknown wireless signal input, each modulation type 2ASK, 2 / 4 / 8FSK, MSK, 2 / 4 / 8PSK, OQPSK, π / 4DQPSK and 16QAM is traversed, and the characteristic parameters of the flatness of the signal envelope extracted from the wireless signal are calculated. QUR, the number of peaks of the normalized power spectrum peakNum, the characteristic parameter kur of the flatness of the normalized power spectrum, and the characteristic parameter of the modulus of the normalized instantaneous frequency These four parameters determine QUR Whether it meets the corresponding decision threshold and signal-to-noise ratio threshold, whether peakNum meets the number of peaks corresponding to different modulation modes, whether kur meets the corresponding decision threshold and signal-to-noise ratio threshold, and whether Whether the corresponding decision threshold and signal-to-noise ratio threshold are met; if a certain modulation mode is traversed, QUR ,peakNum,kur, and If these four parameters simultaneously satisfy the decision thresholds of the corresponding characteristics of this modulation mode, it is considered that the current input signal belongs to this modulation mode, thus completing the blind recognition of the modulation mode for signals of unknown modulation type.

[0067] The modulation mode identification method based on the comprehensive characteristics of wireless signals provided in the embodiment of the present invention sequentially identifies the wireless signal in a target order through at least one candidate modulation type, and determines the first occurrence of the target modulation type as the modulation mode identification result when the comprehensive characteristics satisfy the feature decision threshold and signal-to-noise ratio threshold corresponding to the target modulation type. The target within the modulation type range is found at one time by traversing each modulation type of the type, thereby avoiding repeated complex calculations. At the same time, the process of signal modulation mode identification using efficient threshold decision and step-by-step feature extraction strategies is optimized, thereby significantly reducing the amount of calculations.

[0068] In some embodiments, the comprehensive feature includes a time domain feature; the time domain feature includes envelope smoothness; when the comprehensive feature satisfies a feature decision threshold and a signal-to-noise ratio threshold corresponding to the target modulation type, determining that the target modulation type is a modulation mode recognition result includes: When the feature decision threshold corresponding to the time domain feature is greater than 1.27, and the signal-to-noise ratio threshold corresponding to the time domain feature is greater than or equal to 5dB, the modulation mode recognition result is determined to be 2ASK; when the feature decision threshold corresponding to the time domain feature is between 1.12 and 1.27, and the signal-to-noise ratio threshold corresponding to the time domain feature is greater than or equal to 12dB, the modulation mode recognition result is determined to be 2PSK or 16QAM; when the feature decision threshold corresponding to the time domain feature is between 1.03 and 1.12, and the signal-to-noise ratio threshold corresponding to the time domain feature is greater than or equal to 12dB , determine that the modulation mode recognition result is 4PSK, 8PSK, π / 4DQPSK or 4OQPSK; when the feature decision threshold corresponding to the time domain feature is less than 1.03, and the signal-to-noise ratio threshold corresponding to the time domain feature is greater than or equal to 15dB, determine that the modulation mode recognition result is CW, 2MSK or 2 / 4 / 8FSK; or, when the feature decision threshold corresponding to the time domain feature is less than 1.03, and the signal-to-noise ratio threshold corresponding to the time domain feature is greater than or equal to 12dB, determine that the modulation mode recognition result is 2MSK or 2 / 4 / 8FSK.

[0069] In this embodiment, the envelope smoothness iqR (same as above) QUR ) is set as shown in Table 2: Table 2. iqR decision interval parameter table

[0070] When identifying different modulation modes with comprehensive features as envelope smoothness, this embodiment sets reasonable feature decision thresholds and signal-to-noise ratio thresholds to ensure that the modulation mode identification method can operate efficiently under a variety of signal-to-noise ratios.

[0071] In some embodiments, the comprehensive feature further includes a frequency domain feature; the frequency domain feature includes the number of peaks of the normalized power spectrum; when the comprehensive feature satisfies the feature decision threshold and the signal-to-noise ratio threshold corresponding to the target modulation type, determining that the target modulation type is a modulation mode identification result also includes: When the 1st, 2nd, 4th and 8th power spectra of the wireless signal converge and the number of peaks is 1, the modulation mode identification result is determined to be CW; when the 1st, 2nd, 4th and 8th power spectra of the wireless signal converge, the signal-to-noise ratio threshold corresponding to the 4th power spectrum is greater than or equal to 0dB, the signal-to-noise ratio threshold corresponding to the 8th power spectrum is greater than or equal to 7dB, and the number of peaks is 1, the modulation mode identification result is determined to be 2ASK; when the 2nd, 4th and 8th power spectra of the wireless signal converge, the signal-to-noise ratio threshold corresponding to the 4th power spectrum is greater than or equal to 1 dB, the signal-to-noise ratio threshold corresponding to the 8th power power spectrum is greater than or equal to 8.5dB, and the number of peaks is 1, the modulation mode identification result is determined to be 2PSK; when the 4th power spectrum of the wireless signal converges, the 8th power spectrum partially converges, the signal-to-noise ratio threshold corresponding to the 4th power spectrum is greater than or equal to 4dB, and the number of peaks is 1, the modulation mode identification result is determined to be 4PSK or 4OQPSK; when the 2nd, 4th and 8th power spectrums of the wireless signal converge, the signal-to-noise ratio threshold corresponding to the 2nd power spectrum is greater than or equal to 1dB, the signal-to-noise ratio threshold corresponding to the 4th power spectrum is greater than or equal to 7dB, the signal-to-noise ratio threshold corresponding to the 8th power spectrum is greater than or equal to 13.5dB, and the number of peaks is 2, the modulation mode identification result is determined to be 2MSK.

[0072] In this embodiment, for the peak number peakNum of the normalized power spectrum, the following determination rule can be obtained through simulation: (1) The 1st, 2nd, 4th, and 8th power spectra of the wireless signal are all converged, the signal-to-noise ratio has almost no effect on them, and the number of peaks is always 1, so the modulation mode identification result is CW; (2) The 1st, 2nd, 4th, and 8th powers all converge. The 1st and 2nd power signal-to-noise ratios have almost no effect on them. The 4th power SNR is ≥ 0dB, and the 8th power SNR is ≥ 7dB. The number of peaks is always 1, so the modulation mode identification result is 2ASK. (3) The 2nd, 4th, and 8th powers of the wireless signal all converge, the 2nd power signal-to-noise ratio has almost no effect on it, the 4th power SNR ≥ 1dB, the 8th power SNR ≥ 8.5dB, and the number of its peaks is always 1 after convergence, so the modulation mode identification result is 2PSK; (4) The fourth power of the wireless signal converges, and the fourth power SNR ≥ 4dB. The eighth power does not fully converge and there is a high probability of misjudgment. The high-power operation causes the noise floor to rise, affecting the judgment. The number of peaks is always 1 after convergence, so the modulation mode recognition result is 4PSK; (5) The fourth power of the wireless signal converges, and the fourth power SNR ≥ 4dB. The eighth power does not fully converge and there is a high probability of misjudgment. The number of peaks is always 1 after convergence. The double peaks of the second power cannot be effectively judged. The number of symbols is not enough and the peak is not obvious. The modulation mode recognition result is 4OQPSK. (6) The 2nd, 4th, and 8th powers of the wireless signal all converge, the 2nd power SNR ≥ 1dB, the 4th power SNR ≥ 7dB, and the 8th power SNR ≥ 13.5dB. The number of peaks is always 2 after convergence, so the modulation mode identification result is 2MSK.

[0073] When different modulation modes are identified based on the comprehensive feature of the number of peaks of the normalized power spectrum, this embodiment sets a reasonable peak number decision threshold and signal-to-noise ratio threshold to ensure that the modulation mode identification method can operate efficiently under a variety of signal-to-noise ratios.

[0074] In some embodiments, the frequency domain feature further includes a flatness; when the comprehensive feature satisfies a feature decision threshold and a signal-to-noise ratio threshold corresponding to the target modulation type, determining that the target modulation type is a modulation mode identification result further includes: When the characteristic decision threshold corresponding to the 1st power spectrum of the wireless signal is greater than 0.3, and the corresponding signal-to-noise ratio threshold is greater than -6dB, the characteristic decision threshold corresponding to the 2nd power spectrum is greater than 0.32, and the corresponding signal-to-noise ratio threshold is greater than -6dB, and the characteristic decision threshold corresponding to the 4th power spectrum is greater than 0.3, and the corresponding signal-to-noise ratio threshold is greater than -6dB, the modulation mode identification result is determined to be CW; when the characteristic decision threshold corresponding to the 1st power spectrum of the wireless signal is greater than 0.3, and the corresponding signal-to-noise ratio threshold is greater than -6dB, the characteristic decision threshold corresponding to the 2nd power spectrum is greater than 0.32, and the corresponding signal-to-noise ratio threshold is greater than 1dB, and the characteristic decision threshold corresponding to the 4th power spectrum is greater than 0.27, and the corresponding signal-to-noise ratio threshold is greater than 3 dB, the modulation mode recognition result is determined to be 2ASK; when the corresponding feature decision threshold of the 1st power spectrum of the wireless signal is less than 0.3, and the corresponding signal-to-noise ratio threshold is greater than -6dB, the corresponding feature decision threshold of the 2nd power spectrum is greater than 0.32, and the corresponding signal-to-noise ratio threshold is greater than 1dB, and the corresponding feature decision threshold of the 4th power spectrum is greater than 0.27, and the corresponding signal-to-noise ratio threshold is greater than 3 dB, the modulation mode recognition result is determined to be 2PSK; when the corresponding feature decision threshold of the 1st power spectrum of the wireless signal is less than 0.3, and the corresponding signal-to-noise ratio threshold is greater than -6dB, the corresponding feature decision threshold of the 2nd power spectrum is less than 0.1, and the corresponding signal-to-noise ratio threshold is greater than or equal to -6dB, and the 4th power spectrum meets one of the following conditions: the feature decision threshold of the 4th power spectrum is between 0.1 and 0.4, and the corresponding signal-to-noise ratio threshold is greater than 3 dB, the modulation mode identification result is determined to be 4PSK or π / 4DQPSK; when the characteristic decision threshold of the fourth power spectrum is between 0.25 and 0.4, and the corresponding signal-to-noise ratio threshold is greater than 6dB, the modulation mode identification result is determined to be 4OQPSK; when the characteristic decision threshold of the fourth power spectrum is less than 0.05, and the corresponding signal-to-noise ratio threshold is greater than or equal to -6dB, the modulation mode identification result is determined to be 8PSK; when the corresponding characteristic decision threshold of the first power power spectrum of the wireless signal is less than 0.3, the corresponding signal-to-noise ratio threshold is greater than 6dB, the modulation mode identification result is determined to be 8PSK. The ratio threshold is greater than -6dB, the corresponding feature decision threshold of the square power spectrum is less than 0.3, the corresponding signal-to-noise ratio threshold is greater than or equal to -3dB, and the fourth power spectrum meets one of the following conditions: when the feature decision threshold of the fourth power power spectrum is between 0.15 and 0.35, and the corresponding signal-to-noise ratio threshold is greater than 12dB, the modulation mode recognition result is determined to be 2MSK; when the feature decision threshold of the fourth power power spectrum is less than 0.05, and the corresponding signal-to-noise ratio threshold is greater than -6dB, the modulation mode recognition result is determined to be 8FSK.

[0075] In this embodiment, for the characteristic parameter kur of the flatness of the normalized power spectrum, the corresponding decision condition can be obtained through simulation, as shown in Table 3 below.

[0076] When identifying different modulation modes based on the comprehensive feature of the flatness of the normalized power spectrum, this embodiment sets a reasonable peak quantity decision threshold and signal-to-noise ratio threshold to ensure that the modulation mode identification method can operate efficiently under a variety of signal-to-noise ratios.

[0077] In some embodiments, the comprehensive features further include time-frequency domain features; the time-frequency domain features include the flatness of the modulus of the normalized instantaneous frequency; when the comprehensive features meet the feature decision threshold and signal-to-noise ratio threshold corresponding to the target modulation type, determining that the target modulation type is a modulation mode identification result further includes: When the characteristic decision threshold corresponding to the degree of mode flatness is between 1.8 and 2.5, and the corresponding signal-to-noise ratio threshold is greater than or equal to 10dB, the modulation mode recognition result is determined to be π / 4DQPSK; when the characteristic decision threshold corresponding to the degree of mode flatness is greater than 1.9, and the corresponding signal-to-noise ratio threshold is greater than or equal to 8dB, the modulation mode recognition result is determined to be 2ASK, 2 / 4 / 8PSK or 16QAM; when the characteristic decision threshold corresponding to the degree of mode flatness is between 1.32 and 1.95, and the corresponding signal-to-noise ratio threshold is greater than or equal to 10dB, the modulation mode recognition result is determined to be π / 4DQPSK; when the characteristic decision threshold corresponding to the degree of mode flatness is greater than 1.9, and the corresponding signal-to-noise ratio threshold is greater than or equal to 8dB, the modulation mode recognition result is determined to be 2ASK, 2 / 4 / 8PSK or 16QAM; When the signal-to-noise ratio threshold is greater than or equal to 12dB, the modulation mode identification result is determined to be 4OQPSK or 4 / 8FSK; when the characteristic decision threshold corresponding to the flatness of the mode is between 1.05 and 1.32, and the corresponding signal-to-noise ratio threshold is greater than or equal to 20dB, the modulation mode identification result is determined to be 2FSK or 2MSK; when the characteristic decision threshold corresponding to the flatness of the mode is less than 1.05, and the corresponding signal-to-noise ratio threshold is greater than or equal to 13dB, the modulation mode identification result is determined to be CW.

[0078] In this embodiment, the flatness of the modulus of the normalized instantaneous frequency of the signal is ftNormAbsR ,Through simulation, the following judgment conditions are obtained as shown in Table 4.

[0079] In this embodiment, when different modulation modes are identified based on the comprehensive feature of the flatness of the modulus of the normalized instantaneous frequency, a reasonable peak quantity decision threshold and signal-to-noise ratio threshold are set to ensure that the modulation mode identification method can operate efficiently under a variety of signal-to-noise ratios.

[0080] Figure 2 This is a flow chart of the second method for identifying a modulation mode based on comprehensive characteristics of wireless signals provided by the present invention. Figure 2In the embodiment shown, a modulation mode identification method based on comprehensive characteristics of wireless signals is also implemented by the following steps: (1) determining a modulation signal of unknown modulation type such as amplitude modulation (ASK type), frequency modulation (FSK, MSK type), phase modulation (PSK, OQPSK, DQPSK type), and amplitude modulation phase modulation (QAM, APSK type); (2) obtaining time domain baseband IQ data of the wireless signal; (3) calculating the envelope of the IQ data, and then calculating the characteristic parameter iqR of the flatness of the signal envelope; (4) after the IQ data is raised to the power of p=1, 2, 4, 8, the peak number peakNum of the power spectrum after normalization to 1 is calculated; (5) calculating the signal p= After 1, 2, 4, and 8 powers, the corresponding normalized power spectrum flatness kur is obtained respectively; (6) the phase of the IQ signal is calculated, and then phase difference and unwrapping are performed to calculate the instantaneous frequency and the flatness parameter ftNormAbs of the normalized instantaneous frequency modulus; (7) each modulation type is traversed; (8) it is determined whether the four parameters iqR, peakNum, kur, and ftNormAbs simultaneously meet the decision threshold of the corresponding characteristics of this modulation mode; if so, the corresponding modulation type is output as the recognition result (i.e., the modulation mode recognition result); if not, the next modulation type is traversed. If the traversal is completed, the recognition is considered to have failed.

[0081] Table 3. Kur judgment condition data table

[0082] Table 4. ftNormAbsR decision interval data table

[0083] The modulation mode identification device based on comprehensive characteristics of wireless signals provided by the present invention is described below. The modulation mode identification device based on comprehensive characteristics of wireless signals described below and the modulation mode identification method based on comprehensive characteristics of wireless signals described above can be referred to each other.

[0084] Figure 3 is a schematic diagram of the structure of a modulation mode identification device based on comprehensive characteristics of wireless signals provided by the present invention, such as Figure 3 As shown, the modulation mode identification device based on the comprehensive characteristics of the wireless signal is characterized by comprising: a feature acquisition module 310 and an identification module 320.

[0085] A feature acquisition module 310 is used to acquire a comprehensive feature of a target from a wireless signal, where the comprehensive feature includes at least one of a time domain feature, a frequency domain feature, and a time-frequency domain feature; The identification module 320 is used to identify the wireless signal based on the candidate modulation type, and determine the target modulation type as the modulation mode identification result when the comprehensive characteristics meet the feature decision threshold and signal-to-noise ratio threshold corresponding to the target modulation type; wherein the candidate modulation types include at least one of 2ASK, 2 / 4 / 8FSK, MSK, 2 / 4 / 8PSK, OQPSK, π / 4DQPSK and 16QAM; the target modulation type belongs to the candidate modulation type.

[0086] The modulation mode identification device based on the comprehensive characteristics of wireless signals provided in the embodiment of the present invention obtains the comprehensive characteristics of the target from the wireless signal, and identifies the wireless signal based on the candidate modulation type. When the comprehensive characteristics meet the characteristic decision threshold and signal-to-noise ratio threshold corresponding to the target modulation type, the target modulation type is determined as the modulation mode identification result, thereby improving the modulation mode identification accuracy of the wireless signal.

[0087] Figure 4 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 4 As shown, the electronic device may include: a processor 410, a communication interface 420, a memory 430 and a communication bus 440, wherein the processor 410, the communication interface 420 and the memory 430 communicate with each other through the communication bus 440. The processor 410 may call the logic instructions in the memory 430 to execute a modulation mode identification method based on the comprehensive characteristics of the wireless signal, the method comprising: obtaining the comprehensive characteristics of the target from the wireless signal, the comprehensive characteristics comprising at least one of the time domain characteristics, the frequency domain characteristics and the time-frequency domain characteristics; identifying the wireless signal based on the candidate modulation type, and determining the target modulation type as the modulation mode identification result when the comprehensive characteristics meet the characteristic decision threshold and the signal-to-noise ratio threshold corresponding to the target modulation type; wherein the candidate modulation type comprises at least one of 2ASK, 2 / 4 / 8FSK, MSK, 2 / 4 / 8PSK, OQPSK, π / 4DQPSK and 16QAM; the target modulation type belongs to the candidate modulation type.

[0088] In addition, the logic instructions in the above-mentioned memory 430 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0089] On the other hand, the present invention also provides a computer program product, which includes a computer program, and the computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the modulation mode identification method based on the comprehensive characteristics of the wireless signal provided by the above-mentioned methods, and the method includes: obtaining the comprehensive characteristics of the target from the wireless signal, the comprehensive characteristics including at least one of the time domain characteristics, the frequency domain characteristics and the time-frequency domain characteristics; identifying the wireless signal based on the candidate modulation type, and determining the target modulation type as the modulation mode identification result when the comprehensive characteristics meet the feature decision threshold and signal-to-noise ratio threshold corresponding to the target modulation type; wherein the candidate modulation types include at least one of 2ASK, 2 / 4 / 8FSK, MSK, 2 / 4 / 8PSK, OQPSK, π / 4DQPSK and 16QAM; the target modulation type belongs to the candidate modulation type.

[0090] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the modulation mode identification method based on the comprehensive characteristics of the wireless signal provided by the above-mentioned methods, the method comprising: obtaining the comprehensive characteristics of the target from the wireless signal, the comprehensive characteristics comprising at least one of time domain characteristics, frequency domain characteristics and time-frequency domain characteristics; identifying the wireless signal based on the candidate modulation type, and determining the target modulation type as the modulation mode identification result when the comprehensive characteristics meet the characteristic decision threshold and signal-to-noise ratio threshold corresponding to the target modulation type; wherein the candidate modulation types comprise at least one of 2ASK, 2 / 4 / 8FSK, MSK, 2 / 4 / 8PSK, OQPSK, π / 4DQPSK and 16QAM; the target modulation type belongs to the candidate modulation type.

[0091] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Those of ordinary skill in the art may understand and implement it without creative effort.

[0092] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A modulation mode identification method based on comprehensive characteristics of wireless signals, characterized in that: include: Acquire a comprehensive feature of the target from the wireless signal, wherein the comprehensive feature includes at least one of a time domain feature, a frequency domain feature, and a time-frequency domain feature; The wireless signal is identified based on the candidate modulation types, and when the comprehensive characteristics meet the feature decision threshold and signal-to-noise ratio threshold corresponding to the target modulation type, the target modulation type is determined as the modulation mode identification result; wherein the candidate modulation types include at least one of 2ASK, 2 / 4 / 8FSK, MSK, 2 / 4 / 8PSK, OQPSK, π / 4DQPSK and 16QAM; the target modulation type belongs to the candidate modulation types.

2. The modulation mode identification method based on the comprehensive characteristics of wireless signals according to claim 1 is characterized in that: The time domain feature includes envelope smoothness, and the envelope smoothness is used to distinguish amplitude modulation signals, phase modulation signals and frequency modulation signals; The frequency domain features include the number of peaks and the degree of flatness of the normalized power spectrum, and the frequency domain features are used to characterize the frequency characteristics of the wireless signal; The time-frequency domain feature includes the flatness of the modulus of the normalized instantaneous frequency, and the time-frequency domain feature is used to identify the state frequency change characteristics of the wireless signal.

3. The modulation mode identification method based on comprehensive characteristics of wireless signals according to claim 1 is characterized in that: The comprehensive features include at least two of time domain features, frequency domain features and time-frequency domain features; The identifying of the wireless signal based on the candidate modulation type, and determining that the target modulation type is a modulation mode identification result when the comprehensive feature satisfies the feature decision threshold and the signal-to-noise ratio threshold corresponding to the target modulation type, includes: The wireless signal is identified in sequence according to the target order based on the candidate modulation types, and when the comprehensive feature satisfies the feature decision threshold and signal-to-noise ratio threshold corresponding to the target modulation type, the first appearing target modulation type is determined as the modulation mode identification result; wherein, the target order is determined based on the sequence of time domain features, frequency domain features and time-frequency domain features.

4. The modulation mode identification method based on comprehensive characteristics of wireless signals according to claim 1 is characterized in that: The comprehensive features include time domain features; The time domain features include envelope smoothness; When the comprehensive feature satisfies the feature decision threshold and the signal-to-noise ratio threshold corresponding to the target modulation type, determining that the target modulation type is a modulation mode identification result includes: When the feature decision threshold corresponding to the time domain feature is greater than 1.27 and the signal-to-noise ratio threshold corresponding to the time domain feature is greater than or equal to 5 dB, determining that the modulation mode recognition result is 2ASK; When the feature decision threshold corresponding to the time domain feature is between 1.12 and 1.27, and the signal-to-noise ratio threshold corresponding to the time domain feature is greater than or equal to 12 dB, determining that the modulation mode identification result is 2PSK or 16QAM; When the feature decision threshold corresponding to the time domain feature is between 1.03 and 1.12, and the signal-to-noise ratio threshold corresponding to the time domain feature is greater than or equal to 12 dB, determining that the modulation mode identification result is 4PSK, 8PSK, π / 4DQPSK or 4OQPSK; When the feature decision threshold corresponding to the time domain feature is less than 1.03 and the signal-to-noise ratio threshold corresponding to the time domain feature is greater than or equal to 15 dB, determine that the modulation mode identification result is CW, 2MSK or 2 / 4 / 8FSK; Alternatively, when the feature decision threshold corresponding to the time domain feature is less than 1.03 and the signal-to-noise ratio threshold corresponding to the time domain feature is greater than or equal to 12dB, the modulation mode identification result is determined to be 2MSK or 2 / 4 / 8FSK.

5. The modulation mode identification method based on comprehensive characteristics of wireless signals according to claim 4 is characterized in that: The comprehensive features also include frequency domain features; the frequency domain features include the number of peaks of the normalized power spectrum; In the case where the comprehensive feature satisfies the feature decision threshold and the signal-to-noise ratio threshold corresponding to the target modulation type, determining that the target modulation type is a modulation mode identification result also includes: When the 1st, 2nd, 4th and 8th power spectra of the wireless signal converge and the number of peaks is 1, determining that the modulation mode identification result is CW; When the 1st, 2nd, 4th and 8th power spectra of the wireless signal converge, the signal-to-noise ratio threshold corresponding to the 4th power spectrum is greater than or equal to 0 dB, the signal-to-noise ratio threshold corresponding to the 8th power spectrum is greater than or equal to 7 dB, and the number of peaks is 1, it is determined that the modulation mode identification result is 2ASK; When the 2nd, 4th and 8th power spectra of the wireless signal converge, the signal-to-noise ratio threshold corresponding to the 4th power spectrum is greater than or equal to 1 dB, the signal-to-noise ratio threshold corresponding to the 8th power spectrum is greater than or equal to 8.5 dB, and the number of peaks is 1, it is determined that the modulation mode identification result is 2PSK; When the fourth power spectrum of the wireless signal converges, the eighth power spectrum partially converges, the fourth power power spectrum corresponding to the signal-to-noise ratio threshold is greater than or equal to 4 dB, and the number of peaks is 1, determine that the modulation mode identification result is 4PSK or 4OQPSK; When the 2nd, 4th and 8th power spectra of the wireless signal converge, the signal-to-noise ratio threshold corresponding to the 2nd power spectrum is greater than or equal to 1dB, the signal-to-noise ratio threshold corresponding to the 4th power spectrum is greater than or equal to 7dB, the signal-to-noise ratio threshold corresponding to the 8th power spectrum is greater than or equal to 13.5dB, and the number of peaks is 2, it is determined that the modulation mode identification result is 2MSK.

6. The modulation mode identification method based on comprehensive characteristics of wireless signals according to claim 5 is characterized in that: The frequency domain characteristics also include a flatness level; In the case where the comprehensive feature satisfies the feature decision threshold and the signal-to-noise ratio threshold corresponding to the target modulation type, determining that the target modulation type is a modulation mode identification result also includes: When the characteristic decision threshold corresponding to the power spectrum of the wireless signal to the power of 1 is greater than 0.3, and the corresponding signal-to-noise ratio threshold is greater than -6dB, the characteristic decision threshold corresponding to the power spectrum of the wireless signal to the power of 2 is greater than 0.32, and the corresponding signal-to-noise ratio threshold is greater than -6dB, and the characteristic decision threshold corresponding to the power spectrum of the wireless signal to the power of 4 is greater than 0.3, and the corresponding signal-to-noise ratio threshold is greater than -6dB, it is determined that the modulation mode identification result is CW; When the characteristic decision threshold corresponding to the power spectrum of the wireless signal to the power of 1 is greater than 0.3, the corresponding signal-to-noise ratio threshold is greater than -6 dB, the characteristic decision threshold corresponding to the power spectrum of the wireless signal to the power of 2 is greater than 0.32, the corresponding signal-to-noise ratio threshold is greater than 1 dB, and the characteristic decision threshold corresponding to the power spectrum of the wireless signal to the power of 4 is greater than 0.27, and the corresponding signal-to-noise ratio threshold is greater than 3 dB, the modulation mode identification result is determined to be 2ASK; When the characteristic decision threshold corresponding to the power spectrum of the wireless signal to the power of 1 is less than 0.3, and the corresponding signal-to-noise ratio threshold is greater than -6 dB, the characteristic decision threshold corresponding to the power spectrum of the wireless signal to the power of 2 is greater than 0.32, and the corresponding signal-to-noise ratio threshold is greater than 1 dB, and the characteristic decision threshold corresponding to the power spectrum of the wireless signal to the power of 4 is greater than 0.27, and the corresponding signal-to-noise ratio threshold is greater than 3 dB, it is determined that the modulation mode identification result is 2PSK; The feature decision threshold corresponding to the 1st power spectrum of the wireless signal is less than 0.3, and the corresponding signal-to-noise ratio threshold is greater than -6dB, the feature decision threshold corresponding to the 2nd power spectrum is less than 0.1, and the corresponding signal-to-noise ratio threshold is greater than or equal to -6dB, and the 4th power spectrum meets one of the following conditions: When the characteristic decision threshold of the fourth-power power spectrum is between 0.1 and 0.4 and the corresponding signal-to-noise ratio threshold is greater than 3 dB, determining that the modulation mode identification result is 4PSK or π / 4DQPSK; When the characteristic decision threshold of the power spectrum of the fourth power is between 0.25 and 0.4 and the corresponding signal-to-noise ratio threshold is greater than 6 dB, the modulation mode identification result is determined to be 4OQPSK; When the characteristic decision threshold of the power spectrum of the fourth power is less than 0.05 and the corresponding signal-to-noise ratio threshold is greater than or equal to -6dB, the modulation mode recognition result is determined to be 8PSK; The feature decision threshold corresponding to the 1st power spectrum of the wireless signal is less than 0.3, and the corresponding signal-to-noise ratio threshold is greater than -6dB, the feature decision threshold corresponding to the 2nd power spectrum is less than 0.3, and the corresponding signal-to-noise ratio threshold is greater than or equal to -3dB, and the 4th power spectrum meets one of the following conditions: When the characteristic decision threshold of the fourth power spectrum is between 0.15 and 0.35 and the corresponding signal-to-noise ratio threshold is greater than 12 dB, the modulation mode recognition result is determined to be 2MSK; When the characteristic decision threshold of the fourth power spectrum is less than 0.05 and the corresponding signal-to-noise ratio threshold is greater than -6dB, the modulation mode identification result is determined to be 8FSK.

7. The modulation mode identification method based on the comprehensive characteristics of wireless signals according to claim 5 or 6, characterized in that: The comprehensive features also include time-frequency domain features; the time-frequency domain features include the flatness of the modulus of the normalized instantaneous frequency; In the case where the comprehensive feature satisfies the feature decision threshold and the signal-to-noise ratio threshold corresponding to the target modulation type, determining that the target modulation type is a modulation mode identification result also includes: When the characteristic decision threshold corresponding to the flatness of the mode is between 1.8 and 2.5, and the corresponding signal-to-noise ratio threshold is greater than or equal to 10 dB, determining that the modulation mode identification result is π / 4DQPSK; When the characteristic decision threshold corresponding to the flatness of the mode is greater than 1.9 and the corresponding signal-to-noise ratio threshold is greater than or equal to 8 dB, determining that the modulation mode identification result is 2ASK, 2 / 4 / 8PSK or 16QAM; When the characteristic decision threshold corresponding to the flatness of the mode is between 1.32 and 1.95, and the corresponding signal-to-noise ratio threshold is greater than or equal to 12 dB, determining that the modulation mode identification result is 4OQPSK or 4 / 8FSK; When the characteristic decision threshold corresponding to the flatness of the mode is between 1.05 and 1.32, and the corresponding signal-to-noise ratio threshold is greater than or equal to 20 dB, determining that the modulation mode identification result is 2FSK or 2MSK; When the characteristic decision threshold corresponding to the flatness of the mode is less than 1.05 and the corresponding signal-to-noise ratio threshold is greater than or equal to 13 dB, it is determined that the modulation mode identification result is CW.

8. A modulation mode identification device based on comprehensive characteristics of wireless signals, characterized in that: include: A feature acquisition module, used to acquire a comprehensive feature from the wireless signal, wherein the comprehensive feature includes at least one of a time domain feature, a frequency domain feature, and a time-frequency domain feature; An identification module is used to identify the wireless signal based on candidate modulation types, and determine that the target modulation type is a modulation mode identification result when the comprehensive characteristics meet the feature decision threshold and signal-to-noise ratio threshold corresponding to the target modulation type; wherein the candidate modulation types include at least one of 2ASK, 2 / 4 / 8FSK, MSK, 2 / 4 / 8PSK, OQPSK, π / 4DQPSK and 16QAM; and the target modulation type belongs to the candidate modulation types.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the modulation mode identification method based on the comprehensive characteristics of the wireless signal is implemented as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the modulation mode identification method based on the comprehensive characteristics of the wireless signal is implemented as described in any one of claims 1 to 7.

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