Narrowband wireless same-frequency interference detection method and system based on frequency spectrum hopping and electronic equipment

Abstract

The invention relates to a narrowband wireless same-frequency interference detection method and system based on frequency spectrum hopping and electronic equipment. The method comprises the following steps: acquiring time-domain signal data and preprocessing the time-domain signal data; according to a preset data sampling parameter, converting the preprocessed time domain signal data into frequency domain representation by using fast Fourier transform; calculating an amplitude spectrum represented by a frequency domain; tracking the maximum value of the amplitude spectrum and the corresponding frequency index; according to the tracking condition, judging whether the position where the maximum value is located hops or not, if yes, judging that the same-frequency interference exists when the number of hops exceeds a preset threshold value within preset time, and if not, continuing tracking. Compared with the prior art, the method has the advantages of improving the accuracy and the real-time performance of same-frequency interference detection and the adaptability to a complex interference environment, and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless co-channel interference detection, and in particular to a narrow-band wireless co-channel interference detection method, system and electronic equipment based on spectrum hopping. Background Art

[0002] With the rapid development of wireless communication technology, the increasing shortage of spectrum resources has led to a significant increase in the number of wireless devices. In order to improve the efficiency of spectrum utilization, many wireless communication systems use co-frequency technology, which enables different communication devices to transmit data within the same frequency range. However, while this technology brings convenience, it also causes the problem of co-frequency interference. Wireless co-frequency interference not only affects the communication quality, but also may cause data loss and delay, thus affecting the user experience and system reliability. Therefore, it is particularly important to develop an effective interference detection method.

[0003] Wireless co-channel interference refers to the phenomenon that different wireless devices interfere with each other on the same frequency. This interference mainly comes from signal overlap and interference, which is usually manifested as signal attenuation, distortion and increased noise. Due to differences in factors such as the transmission power, signal modulation method and propagation environment of different devices, the impact of co-channel interference is also uncertain and random. The intensity and frequency characteristics of interference may change in time and space, which brings challenges to interference detection and identification.

[0004] At present, the detection technologies for narrowband wireless co-channel interference mainly include energy detection, matched filtering and cyclic redundancy check. The energy detection method mainly determines the existence of the signal by monitoring the total energy of the signal. However, energy detection is prone to misjudgment in a noisy environment and has weak recognition ability for signal characteristics. Matched filtering is a detection technology based on signal characteristics, which aims to maximize the signal-to-noise ratio of the signal in a noisy background. It processes the received signal by designing a filter that matches the known signal shape. Although matched filtering can effectively improve the signal-to-noise ratio of the signal, it has a strong dependence on the signal model and cannot cope with complex interference environments. Cyclic redundancy check (CRC) technology is based on polynomial division. By treating the data as a polynomial and dividing it with a fixed generating polynomial, a check code (CRC code) is calculated. The receiving end performs the same operation again and compares the calculated CRC code with the received CRC code. This method is mainly used for data integrity checking. It cannot detect the spectrum changes of the signal in real time, resulting in delayed identification of the interference source. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art, such as weak recognition ability, inability to cope with complex interference environment, and inability to detect in real time, and to provide a narrowband wireless co-channel interference detection method, system and electronic equipment based on spectrum hopping.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] According to a first aspect of the present invention, there is provided a narrowband wireless co-channel interference detection method based on spectrum hopping, comprising the following steps: S1, acquiring time domain signal data and performing preprocessing; S2, converting the preprocessed time domain signal data into frequency domain representation using fast Fourier transform according to preset data sampling parameters; S3, calculating the amplitude spectrum of the frequency domain representation; S4, tracking the maximum value of the amplitude spectrum and the corresponding frequency index, and maintaining the frequency index records of at least the first three maximum values ​​at the same time; S5, judging whether there is a hop at the location of the maximum value according to the tracking situation: if yes, then when the number of hops exceeds a preset threshold within a preset time, it is judged that there is co-channel interference, otherwise it returns to S4.

[0008] As a preferred technical solution, the preprocessing process specifically includes: extracting real data and imaginary data from the time domain signal data, and combining the real data and the imaginary data to obtain a complex signal.

[0009] As a preferred technical solution, S2 specifically includes: storing the complex signal into a preset buffer, and performing fast Fourier transform in groups, while utilizing the symmetry and periodicity of discrete Fourier transform, decomposing the signal by divide-and-conquer method for recursive calculation, and finally merging the results to obtain a frequency domain representation.

[0010] As a preferred technical solution, S3 specifically includes: normalizing the amplitude of the frequency domain representation, and converting the obtained amplitude into decibel representation.

[0011] As a preferred technical solution, S4 specifically includes: setting a sliding window, reading the maximum frequency index of three sets of frequency domain data each time, and simultaneously maintaining the frequency index records of the first three maximum values; wherein, the simultaneous maintenance of the frequency index records of the first three maximum values ​​specifically includes: setting the frequency indexes of the three maximum values ​​to be f1, f2, and f3, respectively, using fast Fourier transform to update the frequency domain data, and recording the frequency index of the maximum value of the amplitude spectrum in the current frequency domain as f in each cycle new , the update rules are as follows: after the fast Fourier transform iteration, the original f2 is assigned to f1; the original f3 is assigned to f2; the frequency index f of the maximum value of the amplitude spectrum calculated by the new fast Fourier transform is new Assign the value to f3.

[0012] As a preferred technical solution, S5 specifically includes: extracting the maximum frequency index of each frame in the amplitude spectrum, and performing pattern matching on the time series of the corresponding position of the maximum index within a preset sliding window, thereby detecting the specific regularity of the short-time changes of the main frequency component of the amplitude spectrum.

[0013] As a preferred technical solution, the specific regularity specifically includes: combining the frequency index of the maximum value into a one-dimensional vector, and obtaining a eigenvalue in combination with a preset feature detection vector, and when the intersection of the eigenvalue and the one-dimensional vector is an empty set, it is determined that a spectrum jump occurs.

[0014] As a preferred technical solution, a global variable is set, and the number of jumps is counted using the global variable, and the value of the global variable within the preset time is counted. When the value of the global variable exceeds the preset threshold, it is determined that there is co-channel interference.

[0015] According to a second aspect of the present invention, there is provided a narrowband wireless co-channel interference detection system based on spectrum hopping, comprising a signal sending module, a signal receiving module and a control module, wherein the control module connects the signal sending module and the signal receiving module; the signal sending module and the signal receiving module are respectively used for sending and receiving signals, and the two modules have the same structure, both comprising a signal receiving unit, a signal processing unit, a system clock, a storage unit, an interface unit, an analog-to-digital converter, a digital-to-analog converter and a directional transmitting antenna; the control module is used for controlling the sending and receiving of signals, and executing the described method.

[0016] According to a third aspect of the present invention, there is provided an electronic device, comprising a memory, a processor, and a program stored in the memory, wherein the processor implements the method when executing the program.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The present invention converts the time domain signal into the frequency domain signal through fast Fourier transform, extracts the spectrum characteristics, calculates the amplitude spectrum, and then determines whether a jump occurs by tracking the maximum value change law of the amplitude spectrum, providing a basis for interference management. This method mainly focuses on the dynamic change characteristics of the spectrum. By monitoring the jump of the spectrum, the existence and characteristics of the same-frequency interference can be effectively identified. Compared with the traditional method, it has stronger real-time and accuracy and can quickly adapt to complex wireless environments;

[0019] 2. The present invention sets a sliding window, reads the maximum frequency index of three sets of frequency domain data each time, and simultaneously maintains the frequency index records of the first three maximum values, and determines whether a jump occurs based on the index records. The reason is that when co-channel interference occurs, the crystal oscillator frequency will produce a slight deviation. After the signal source and the interference source are superimposed, the position of the maximum power value in the spectrum will change rapidly. Under normal circumstances, the second maximum value position should be the same as the first or third maximum value position. If the second maximum value position is not equal to the first and third maximum value positions, it is determined that a jump occurs. This method can quickly and accurately realize co-channel interference detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic flow chart of the method provided by the present invention;

[0021] Figure 2 It is a frequency domain schematic diagram when there is no co-channel interference and when there is co-channel interference in Embodiment 1 of the present invention;

[0022] Figure 3 It is a schematic diagram of the maximum value occurrence position when there is no co-channel interference and when there is co-channel interference in Example 1 of the present invention. DETAILED DESCRIPTION

[0023] In order to solve the problems of weak recognition ability, inability to cope with complex interference environments, and inability to detect in real time based on energy detection, matched filtering and cyclic redundancy check methods, the present invention proposes a narrowband wireless co-channel interference detection method, system and electronic equipment based on spectrum hopping, which can monitor and process time domain signal data in real time, track the maximum value of the frequency domain amplitude spectrum, and determine whether a hopping occurs, thereby providing feedback on whether co-channel interference occurs, effectively improving the accuracy, real-time nature and adaptability of co-channel interference detection to complex interference environments.

[0024] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0025] Embodiment 1:

[0026] like Figure 1 As shown, this embodiment provides a narrowband wireless co-channel interference detection method based on spectrum hopping, comprising the following steps:

[0027] Step S1, obtaining time domain signal data and performing preprocessing.

[0028] Specifically, a high-performance spectrum analyzer is used to collect wireless signal data, start spectrum monitoring, collect time domain signal data, and record the time domain signal data in the form of a two-dimensional array.

[0029] The preprocessing process specifically includes: extracting real data and imaginary data from the acquired two-dimensional array, and combining the real data and imaginary data to obtain a complex signal. Specifically:

[0030] Assume that I and Q represent the real and imaginary parts of the complex signal respectively, and both are arrays of length N. Then the complex signal iq-complex can be expressed as:

[0031] iq_complex=I+j*Q (1)

[0032] Where j is an imaginary unit, satisfying j 2 = -1, the final iq_complex is an array containing N complex elements, each of which consists of the corresponding real part I[n] and imaginary part Q[n], that is:

[0033] iq_complex[n]=I[n]+j*Q[n],n=0,1,……,N-1 (2)

[0034] Step S2, according to the preset data sampling parameters, the pre-processed time domain signal data is converted into frequency domain representation using fast Fourier transform.

[0035] Specifically, the data sampling parameters are set, including the number of sampling points and the sampling frequency. Step S2 specifically includes: storing the complex signal obtained in step S1 in a preset buffer, and grouping the data in the buffer for fast Fourier transform (FFT), using the symmetry and periodicity of discrete Fourier transform (DFT), decomposing the signal by divide-and-conquer method for recursive calculation, and finally merging the results. For a sequence x[n]n=0, 1, ..., N-1 with a length of N, the definition of DFT is:

[0036]

[0037] Where X[k] is the kth component of the frequency domain signal, x[n] is the nth sample of the time domain signal (corresponding to iq-complex[n]), is a complex exponential function, representing the rotation factor, and i is the imaginary unit.

[0038] Step S3, calculating the amplitude spectrum represented in the frequency domain.

[0039] Specifically, the frequency domain representation is normalized, that is, the FFT result is divided by the signal length to achieve amplitude normalization, and the obtained amplitude is converted to decibel (dB) representation. The calculation formula is as follows:

[0040]

[0041] Where P is power and P0 is reference power.

[0042] Figure 2 Part (a) is a frequency domain diagram when there is no co-channel interference, and part (b) is a frequency domain diagram when co-channel interference occurs. X in the figure represents the point number corresponding to the maximum power value, and Y represents the maximum power value of the signal.

[0043] Step S4, tracking the maximum value of the amplitude spectrum and the corresponding frequency index, and maintaining at least the frequency index records of the first three maximum values ​​at the same time.

[0044] In this embodiment, a sliding window is set to read the maximum frequency index of three sets of frequency domain data each time, and simultaneously maintain the frequency index records of the first three maximum values. The specific process of simultaneously maintaining the frequency index records of the first three maximum values ​​includes:

[0045] Set the frequency indexes of the three maximum values ​​to f1, f2, and f3 respectively, use FFT to update the frequency domain data, and record the frequency index of the maximum value of the amplitude spectrum in the current frequency domain as f in each loop new , the update rules are as follows:

[0046] After FFT iteration, the original f2 is assigned to f1, that is, f1 = f2;

[0047] Assign the original f3 to f2, that is, f2 = f3;

[0048] The frequency index f of the maximum value of the amplitude spectrum calculated by the new FFT new Assign value to f3, that is, f3 = f new .

[0049] Figure 3 Parts (a) and (b) are schematic diagrams of the maximum value position when there is no co-channel interference, and parts (c) and (d) are schematic diagrams of the maximum value position when co-channel interference occurs. In the figure, X represents the number of fast Fourier transform cycles, and Y represents the position where the maximum power value appears.

[0050] Step S5, judging whether there is a jump at the position of the maximum value according to the tracking situation: if yes, when the number of jumps exceeds the preset threshold within the preset time, it is judged that there is co-channel interference, otherwise return to step S4.

[0051] Specifically, the recorded frequency index tracking data is detected by extracting the maximum frequency index of each frame in the amplitude spectrum and performing pattern matching on the time series of the corresponding position of the maximum index in a preset sliding window, thereby detecting the specific regularity of the short-time changes of the main frequency component of the amplitude spectrum, which is used to analyze the transient characteristics of the signal.

[0052] Among them, specific regularities include:

[0053] Combine the frequency index of the maximum value into a one-dimensional vector M = [f1, f2, f3], set the feature detection vector to T = [1, -1, 1], and the eigenvalue Y = M·T. When , it is determined that spectrum hopping occurs.

[0054] Optionally, a global variable is set to count the number of jumps, and the value of the global variable within a time period of Δt is counted. When the value of the global variable exceeds a preset threshold value δ, it is determined that there is co-channel interference.

[0055] Embodiment 2:

[0056] This embodiment provides a narrowband wireless co-channel interference detection system based on spectrum hopping, the system includes a signal sending module, a signal receiving module and a control module, and the control module connects the signal sending module and the signal receiving module. Among them, the signal sending module and the signal receiving module are used to send and receive signals respectively, and the two modules have the same structure, both including a signal receiving unit, a signal processing unit, a system clock, a storage unit, an interface unit, an analog-to-digital converter, a digital-to-analog converter and a directional transmitting antenna; the control module is used to control the sending and receiving of the signal, and execute one or more steps of the method in Example 1, such as executing the fast Fourier transform of step S2 and the calculation of the amplitude spectrum of step S3. The specific execution process is the same as that in Example 1, and will not be repeated here.

[0057] Further, this embodiment also provides an electronic device, including a memory, a processor, and a program stored in the memory, and the processor implements one or more steps of the method in Example 1 when executing the program. The device processor includes a central processing unit (CPU), which can perform various appropriate actions and processes according to computer program instructions stored in a read-only memory (ROM) or computer program instructions loaded from a storage unit to a random access memory (RAM). In the RAM, various programs and data required for the operation of the device can also be stored. The CPU, ROM, and RAM are connected to each other through a bus. The input / output (I / O) interface is also connected to the bus. Multiple components in the device are connected to the I / O interface, including: input units, such as keyboards, mice, etc.; output units, such as various types of displays, speakers, etc.; storage units, such as disks, optical disks, etc.; and communication units, such as network cards, modems, wireless communication transceivers, etc. The communication unit allows the device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunication networks. The processing unit performs the various methods and processes described above, such as one or more steps of the method in the aforementioned embodiment 1. For example, in some embodiments, one or more steps of the method in embodiment 1 may be implemented as a computer software program, which is tangibly contained in a machine-readable medium, such as a storage unit. In some embodiments, part or all of the computer program may be loaded and / or installed on the device via a ROM and / or a communication unit. When the computer program is loaded into the RAM and executed by the CPU, one or more steps of the method in embodiment 1 described above may be executed. Alternatively, in other embodiments, the CPU may be configured to execute one or more steps of the method in embodiment 1 by any other appropriate means (e.g., by means of firmware). The functions described above may be performed at least in part by one or more hardware logic components. For example, without limitation, exemplary types of hardware logic components that may be used include: field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), complex programmable logic devices (CPLDs), and the like.

[0058] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A narrowband wireless co-channel interference detection method based on spectrum hopping, characterized in that: The following steps are involved: S1, obtain time domain signal data and perform preprocessing; S2, converting the preprocessed time domain signal data into frequency domain representation using fast Fourier transform according to preset data sampling parameters; S3, calculating the amplitude spectrum of the frequency domain representation; S4, tracking the maximum value of the amplitude spectrum and the corresponding frequency index, and maintaining at least the frequency index records of the first three maximum values ​​at the same time; S5, judging whether there is a jump at the position of the maximum value according to the tracking situation: If yes, when the number of jumps exceeds a preset threshold within a preset time, it is determined that there is co-channel interference, otherwise the process returns to S4.

2. The narrowband wireless co-channel interference detection method based on spectrum hopping according to claim 1 is characterized in that: The preprocessing process specifically includes: extracting real data and imaginary data from the time domain signal data, and combining the real data and the imaginary data to obtain a complex signal.

3. The narrowband wireless co-channel interference detection method based on spectrum hopping according to claim 2 is characterized in that: The S2 specifically includes: storing the complex signal into a preset buffer, performing fast Fourier transform in groups, and utilizing the symmetry and periodicity of discrete Fourier transform to decompose the signal through a divide-and-conquer method for recursive calculation, and finally merging the results to obtain a frequency domain representation.

4. The narrowband wireless co-channel interference detection method based on spectrum hopping according to claim 1, characterized in that: The S3 specifically includes: normalizing the amplitude of the frequency domain representation, and converting the obtained amplitude into decibel representation.

5. The narrowband wireless co-channel interference detection method based on spectrum hopping according to claim 1, characterized in that: The S4 specifically includes: setting a sliding window, reading the maximum frequency index of three sets of frequency domain data each time, and simultaneously maintaining the frequency index records of the first three maximum values; wherein, the simultaneous maintenance of the frequency index records of the first three maximum values ​​specifically includes: setting the frequency indexes of the three maximum values ​​to be f1, f2, and f3, respectively, using fast Fourier transform to update the frequency domain data, and recording the frequency index of the maximum value of the amplitude spectrum in the current frequency domain as f in each cycle new , the update rules are as follows: After the fast Fourier transform iteration, the original f2 is assigned to f1; Assign the original f3 to f2; The frequency index f of the maximum value of the amplitude spectrum calculated by the new fast Fourier transform new Assign the value to f3.

6. The narrowband wireless co-channel interference detection method based on spectrum hopping according to claim 1, characterized in that: The S5 specifically includes: extracting the maximum frequency index of each frame in the amplitude spectrum, and performing pattern matching on the time series of the position corresponding to the maximum index in a preset sliding window, thereby detecting the specific regularity of the short-term variation of the main frequency component of the amplitude spectrum.

7. The narrowband wireless co-channel interference detection method based on spectrum hopping according to claim 6, characterized in that: The specific regularities specifically include: The frequency index of the maximum value is combined into a one-dimensional vector, and combined with a preset feature detection vector to obtain a feature value, and when the intersection of the feature value and the one-dimensional vector is an empty set, it is determined that a spectrum jump occurs.

8. The narrowband wireless co-channel interference detection method based on spectrum hopping according to claim 1, characterized in that: A global variable is set, and the number of jumps is counted using the global variable, and the value of the global variable within the preset time is counted. When the value of the global variable exceeds the preset threshold, it is determined that there is co-channel interference.

9. A narrowband wireless co-channel interference detection system based on spectrum hopping, characterized in that: It includes a signal sending module, a signal receiving module and a control module, wherein the control module connects the signal sending module and the signal receiving module; The signal sending module and the signal receiving module are used for sending and receiving signals respectively, and the two modules have the same structure, and both include a signal receiving unit, a signal processing unit, a system clock, a storage unit, an interface unit, an analog-to-digital converter, a digital-to-analog converter, and a directional transmitting antenna; The control module is used to control the sending and receiving of signals and execute the method according to any one of claims 1-8.

10. An electronic device comprising a memory, a processor, and a program stored in the memory, characterized in that: When the processor executes the program, the method according to any one of claims 1 to 8 is implemented.

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