Method and system for analyzing Hash value of radio signal

Abstract

The invention discloses an analysis method and system for a radio signal hash value, and belongs to the technical field of radio signal rapid retrieval, and the method comprises the steps: obtaining radio signals, unifying the sampling rate and length of the signals, and carrying out the Fourier transformation of the radio signals with a certain length, and obtaining a transformation coefficient; and intercepting the change coefficient into a plurality of Fourier transform low-frequency coefficients according to the required Hash value length, obtaining each bit of the Hash value by calculating the average value of the amplitudes of the Fourier transform low-frequency coefficients, and generating the Hash value of the radio signal. According to the method, the radio signals are converted into the Hash values represented by the integers, signals similar to the specified radio signals can be retrieved from a database with massive radio signals, the further processing range is narrowed, and the method has important application value in frequency networking.

Description

Technical Field

[0001] The present invention relates to the technical field of rapid retrieval of radio signals, and in particular to a method and system for analyzing hash values ​​of radio signals. Background Art

[0002] In fields such as radio spectrum management, it is usually necessary to collect a large number of radio signals to form a signal library, which is used to determine the signal category, the equipment using the radio spectrum, and the frequency usage behavior of the equipment.

[0003] With technological advancements, the radio spectrum continues to expand, radio communication rates continue to increase, and the scale of collected radio signals is growing, resulting in the formation of radio signal big data. Finding signals similar to a given signal within this big data requires a significant amount of time and computing resources. To address this, a multi-stage search approach is often employed. Simple features are first used to search for candidate signals similar to the given signal, and then complex features are used to further refine the search for similar signals within the candidate signals, accelerating the signal retrieval process.

[0004] The method for calculating simple characteristics of radio signals is to calculate the hash value of the radio signals. This hash value is called a perceptual hash value, which requires similar radio signals to have similar hash values. Currently, there is no effective perceptual hash calculation method for radio signals. This invention is based on this practical need. Summary of the Invention

[0005] In order to solve the above problems, the purpose of the present invention is to provide an analysis technology for radio signal hash values ​​to meet the demand for rapid retrieval of radio signals.

[0006] In order to achieve the above technical objectives, the present application provides a method for analyzing radio signal hash values, comprising the following steps:

[0007] After acquiring the radio signal and unifying the sampling rate and length of the signal, the radio signal of a certain length is subjected to Fourier transform to obtain the transform coefficients;

[0008] According to the required hash value length, the variation coefficient is truncated into several Fourier transform low-frequency coefficients. By calculating the average amplitude of several Fourier transform low-frequency coefficients, each bit of the hash value is obtained to generate the hash value of the radio signal.

[0009] Preferably, in the process of unifying the sampling rate of the signal, the sampling rate f of the signal is determined. If the actual sampling rate of the signal is less than f, the sampling rate of the signal is increased by interpolation; if the actual sampling rate of the signal is greater than f, the sampling rate of the signal is reduced by sampling.

[0010] Preferably, in the process of unifying the length of the signal, the signal length n of the signal is determined. If the actual length of the signal is less than n, 0 is added to the end of the signal; if the actual length of the signal is greater than n, the signal is divided into several segments, and the overlap of any two signal segments is between n / 4 and n / 2.

[0011] Preferably, in the process of performing Fourier transform on the radio signal, after the radio signal sequence is represented as a complex sequence, discrete Fourier transform is performed to obtain transform coefficients.

[0012] Preferably, in the process of obtaining the Fourier transform low-frequency coefficients, the variation coefficients are truncated into m Fourier transform low-frequency coefficients according to the hash value length m, wherein the first coefficient is retained or discarded during the truncation process.

[0013] Preferably, in the process of obtaining the amplitude, the amplitude is calculated based on the Fourier transform low-frequency coefficient using a square root method.

[0014] Preferably, in the process of obtaining the bit position, the average value A of the m low-frequency coefficient amplitudes A(i) is obtained, and each bit b(i) of the hash value is calculated according to the size relationship of A(i) relative to the average value A, wherein if A(i) ≥ A, then b(i) = 1, otherwise, b(i) = 0, and b(i) is regarded as the i-th bit of an integer.

[0015] The present invention discloses a system for analyzing radio signal hash values, comprising:

[0016] A signal processing module is used to obtain radio signals and unify the sampling rate and length of the signals, and then perform Fourier transform on radio signals of a certain length to obtain transform coefficients;

[0017] The hash value analysis module is used to truncate the variation coefficient into several Fourier transform low-frequency coefficients according to the required hash value length, obtain each bit of the hash value by calculating the average amplitude of several Fourier transform low-frequency coefficients, and generate the hash value of the radio signal.

[0018] Preferably, the signal processing module is also used to unify the sampling rate of the signal based on the relationship between the sampling rate f of the signal and the actual sampling rate of the signal. If the actual sampling rate of the signal is less than f, the sampling rate of the signal is increased by interpolation; if the actual sampling rate of the signal is greater than f, the sampling rate of the signal is reduced by sampling.

[0019] Preferably, the signal processing module is also used to unify the length of the signal based on the relationship between the signal length n and the actual length of the signal. If the actual length of the signal is less than n, 0 is added to the end of the signal; if the actual length of the signal is greater than n, the signal is divided into several segments, and the overlap of any two signal segments is between n / 4 and n / 2.

[0020] The present invention discloses the following technical effects:

[0021] The present invention converts radio signals into hash values ​​represented by integers, which is conducive to retrieving signals similar to specified radio signals in a massive radio signal database, narrowing the scope of further processing, and has important application value in frequency networking. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 It is a schematic flow chart of the method described in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of this application.

[0025] like Figure 1 As shown, the present invention provides a method for analyzing a radio signal hash value, comprising the following steps:

[0026] After acquiring the radio signal and unifying the sampling rate and length of the signal, the radio signal of a certain length is subjected to Fourier transform to obtain the transform coefficients;

[0027] According to the required hash value length, the variation coefficient is truncated into several Fourier transform low-frequency coefficients. By calculating the average amplitude of several Fourier transform low-frequency coefficients, each bit of the hash value is obtained to generate the hash value of the radio signal.

[0028] Further preferably, the analysis method for the hash value of a radio signal provided by the present invention determines the sampling rate f of the signal in the process of unifying the sampling rate of the signal. If the actual sampling rate of the signal is less than f, the sampling rate of the signal is increased by interpolation; if the actual sampling rate of the signal is greater than f, the sampling rate of the signal is reduced by sampling.

[0029] Further preferably, the analysis method for the hash value of a radio signal provided by the present invention determines the signal length n of the signal in the process of unifying the length of the signal. If the actual length of the signal is less than n, the method of adding 0 after the signal is adopted; if the actual length of the signal is greater than n, the method of dividing the signal into several segments is adopted, and the overlap of any two signal segments is between n / 4 and n / 2.

[0030] Further preferably, in the method for analyzing hash values ​​of radio signals provided by the present invention, in the process of Fourier transforming the radio signals, after the radio signal sequence is represented as a complex sequence, discrete Fourier transform is performed to obtain transform coefficients.

[0031] Further preferably, the analysis method for the hash value of a radio signal provided by the present invention, in the process of obtaining the Fourier transform low-frequency coefficient, truncates the variation coefficient into m Fourier transform low-frequency coefficients according to the hash value length m, wherein, in the truncation process, the first coefficient is retained or discarded.

[0032] Further preferably, in the analysis method for the hash value of a radio signal provided by the present invention, in the process of obtaining the amplitude, the amplitude is calculated using a square root method based on the low-frequency coefficient of Fourier transform.

[0033] Further preferably, the analysis method for the hash value of a radio signal provided by the present invention obtains the average value A of the m low-frequency coefficient amplitudes A(i) in the process of obtaining the bit position, and calculates each bit b(i) of the hash value based on the size relationship of A(i) relative to the average value A, wherein if A(i) ≥ A, then b(i) = 1, otherwise, b(i) = 0, and b(i) is the i-th bit of an integer.

[0034] The present invention discloses a radio signal hash value analysis system, which is used to implement the above-mentioned radio signal hash value analysis method, including:

[0035] A signal processing module is used to obtain radio signals and unify the sampling rate and length of the signals, and then perform Fourier transform on radio signals of a certain length to obtain transform coefficients;

[0036] The hash value analysis module is used to truncate the variation coefficient into several Fourier transform low-frequency coefficients according to the required hash value length, obtain each bit of the hash value by calculating the average amplitude of several Fourier transform low-frequency coefficients, and generate the hash value of the radio signal.

[0037] Further preferably, the signal processing module of the analysis system for the hash value of a radio signal disclosed in the present invention is also used to unify the sampling rate of the signal according to the relationship between the sampling rate f of the signal and the actual sampling rate of the signal, wherein, if the actual sampling rate of the signal is less than f, the sampling rate of the signal is increased by interpolation; if the actual sampling rate of the signal is greater than f, the sampling rate of the signal is reduced by sampling.

[0038] Further preferably, the signal processing module of the analysis system for the hash value of a radio signal disclosed in the present invention is also used to unify the length of the signal according to the relationship between the signal length n and the actual length of the signal, wherein, if the actual length of the signal is less than n, a method of adding 0 after the signal is adopted; if the actual length of the signal is greater than n, a method of dividing the signal into several segments is adopted, and the overlap of any two signal segments is between n / 4 and n / 2.

[0039] Embodiment: The present invention provides a radio signal hash value analysis technology, which specifically includes the following contents:

[0040] (1) Signal normalization step: Process the signal to unify the sampling rate and length of the signal to facilitate comparison of signal similarity.

[0041] (2) Signal transformation step. After the radio signal sequence (I(i), Q(i)) of length n is expressed as a complex number sequence (I(i) + j*Q(i)), its Fourier transform is calculated to obtain the transform coefficients (u(i) + j*v(i)), where i = 1, 2, …, n. j represents the imaginary part of the complex number.

[0042] (3) Coefficient truncation step. According to the required hash value length m, the first m Fourier transform low-frequency coefficients (u(i) + j*v(i)) are truncated, where i = 1, 2, ..., m. j represents the imaginary part of the complex number.

[0043] (4) Amplitude calculation step: Calculate the amplitude A(i) of the m low-frequency coefficients that have been cut.

[0044] (5) Hash value calculation step: Calculate the average value A of the m low-frequency coefficient amplitudes A(i), and calculate each bit b(i) of the hash value based on the size relationship between A(i) and the average value A.

[0045] (1) Signal normalization step: Process the signal to unify the sampling rate and length of the signal to facilitate comparison of signal similarity.

[0046] During implementation, determine the signal sampling rate f and signal length n. For example, assume the signal sampling rate f is 4 million times per second and the signal length n is 2048. If the actual signal sampling rate is less than f, interpolation can be used to increase the sampling rate. If the actual signal sampling rate is greater than f, decimation can be used to reduce the sampling rate. If the actual signal length is less than n, padding the signal with zeros can be used. If the actual signal length is greater than n, the signal can be divided into several segments, requiring that the overlap between any two segments is between n / 4 and n / 2.

[0047] (2) Signal transformation step: After the radio signal sequence (I(i), Q(i)) of length n is expressed as a complex number sequence (I(i) + j*Q(i)), its Fourier transform is calculated to obtain the transform coefficients (u(i) + j*v(i)), where i = 1, 2, …, n. j represents the imaginary part of the complex number.

[0048] In specific implementations, since the radio signal is discretized after use, a discrete Fourier transform is used to treat the radio signal represented by the I and Q components as a complex number I+j*Q. After transformation, the complex coefficient U+j*V is obtained. j represents the imaginary part of the complex number.

[0049] (3) Coefficient truncation step: According to the required hash value length m, m Fourier transform low-frequency coefficients (u(i)+j*v(i)) are truncated, where i=1, 2, …, m. j represents the imaginary part of the complex number.

[0050] In practice, m is typically set to 32 or 64 for ease of integer processing. The first m Fourier transform low-frequency coefficients (u(i) + j*v(i)) are truncated, where i = 1, 2, ..., m. Alternatively, the first coefficient is discarded, and m Fourier transform low-frequency coefficients (u(i) + j*v(i)) are truncated, where i = 2, 3, ..., m + 1. j represents the imaginary part of the complex number.

[0051] (4) Amplitude calculation step: Calculate the amplitude A(i) of the m low-frequency coefficients that have been cut.

[0052] In specific implementation, the square root method is used.

[0053] (5) Hash value calculation steps: Calculate the average value A of the m low-frequency coefficient amplitudes A(i), and calculate each bit b(i) of the hash value based on the size relationship of A(i) relative to the average value A.

[0054] When implementing it specifically, If A(i)≥A, then b(i)=1, otherwise, b(i)=0, where b(i) is the i-th bit of an integer.

[0055] The present invention converts radio signals into hash values ​​represented by integers, which is conducive to retrieving signals similar to specified radio signals in a massive radio signal database, narrowing the scope of further processing, and has important application value in frequency networking.

[0056] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0057] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0058] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for analyzing a radio signal hash value, characterized in that: The following steps are involved: After acquiring the radio signal and unifying the sampling rate and length of the signal, Fourier transform is performed on the radio signal of a certain length to obtain the transform coefficient; According to the required hash value length, the variation coefficient is truncated into several Fourier transform low-frequency coefficients, and each bit of the hash value is obtained by calculating the average value of the amplitude of several Fourier transform low-frequency coefficients to generate the hash value of the radio signal.

2. The method for analyzing the hash value of a radio signal according to claim 1, characterized in that: In the process of unifying the sampling rate of the signal, the sampling rate f of the signal is determined. If the actual sampling rate of the signal is less than f, the sampling rate of the signal is increased by interpolation; if the actual sampling rate of the signal is greater than f, the sampling rate of the signal is reduced by sampling.

3. The method for analyzing the hash value of a radio signal according to claim 2, characterized in that: In the process of unifying the length of the signal, the signal length n of the signal is determined. If the actual length of the signal is less than n, 0 is added after the signal. If the actual length of the signal is greater than n, the signal is divided into several segments, and the overlap of any two signal segments is between n / 4 and n / 2.

4. The method for analyzing the hash value of a radio signal according to claim 3, characterized in that: In the process of performing Fourier transform on the radio signal, after the radio signal sequence is represented as a complex sequence, discrete Fourier transform is performed to obtain the transform coefficients.

5. The method for analyzing the hash value of a radio signal according to claim 4, characterized in that: In the process of obtaining the Fourier transform low-frequency coefficients, the variation coefficients are truncated into m Fourier transform low-frequency coefficients according to the hash value length m, wherein the first coefficient is retained or discarded during the truncation process.

6. The method for analyzing the hash value of a radio signal according to claim 5, characterized in that: In the process of obtaining the amplitude, the amplitude is calculated based on the Fourier transform low-frequency coefficient using a square root method.

7. The method for analyzing the hash value of a radio signal according to claim 6, characterized in that: In the process of obtaining the bit positions, the average value A of the m low-frequency coefficient amplitudes A(i) is obtained, and each bit b(i) of the hash value is calculated according to the size relationship of A(i) relative to the average value A, wherein if A(i)≥A, then b(i)=1, otherwise, b(i)=0, and b(i) is regarded as the i-th bit of an integer.

8. A system for analyzing radio signal hash values, characterized in that: include: A signal processing module is used to obtain a radio signal and unify the sampling rate and length of the signal, and then perform Fourier transform on a radio signal of a certain length to obtain a transform coefficient; The hash value analysis module is used to truncate the variation coefficient into a number of Fourier transform low-frequency coefficients according to the required hash value length, obtain each bit of the hash value by calculating the average value of the amplitude of the number of Fourier transform low-frequency coefficients, and generate the hash value of the radio signal.

9. The system for analyzing radio signal hash values ​​according to claim 8, characterized in that: The signal processing module is also used to unify the sampling rate of the signal according to the relationship between the sampling rate f of the signal and the actual sampling rate of the signal. If the actual sampling rate of the signal is less than f, the sampling rate of the signal is increased by interpolation; if the actual sampling rate of the signal is greater than f, the sampling rate of the signal is reduced by sampling.

10. The system for analyzing radio signal hash values ​​according to claim 9, characterized in that: The signal processing module is also used to unify the length of the signal according to the relationship between the signal length n and the actual length of the signal. If the actual length of the signal is less than n, 0 is added after the signal; if the actual length of the signal is greater than n, the signal is divided into several segments, and the overlap of any two signal segments is between n / 4 and n / 2.

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