Low frequency communication anti-interference method and system

Abstract

The application discloses a low-frequency communication anti-interference method and system, and belongs to the field of wireless communication. The method adopts an electric antenna and a magnetic antenna to realize the reception of low-frequency communication signals. Compared with the prior art which adopts multiple electric antennas and needs to maintain a certain antenna spacing to ensure spatial resolution, the method has lower requirements on the antenna spacing, and the antennas are closer to each other, thereby saving the space required for placing the antennas, and the receiving end does not need a large space to receive low-frequency signals. Moreover, the application adopts two different antennas, and the responses to near-field and far-field signals are different, so that better spatial resolution can be provided, and the effect of multi-antenna processing is better. In addition, the number of the electric antenna and the magnetic antenna in the application can be flexibly changed according to actual measurement requirements and space requirements.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of wireless communication, and more particularly, relates to a low-frequency communication anti-interference method and system. BACKGROUND

[0002] The anti-interference means of low-frequency communication currently mainly focuses on time-domain anti-interference and frequency-domain anti-interference. Typical time-domain anti-interference is, for example, anti-lightning interference, and typical frequency-domain anti-interference is, for example, anti-narrowband interference. Both of the two kinds of interference have the locality in time domain or frequency domain, so that the anti-interference processing can be performed from the two aspects of time domain and frequency domain.

[0003] Some interference does not have the locality in time domain or frequency domain, so that the time-domain or frequency-domain anti-interference technology cannot be effectively applied. For these interferences, the spatial locality of the interference needs to be used to resist the interference. At present, there is no effective means for effectively using the spatial locality of the interference to resist the interference in the field of low-frequency communication. The main reason is that the spatial anti-interference needs to use multiple antennas, and the interval between the antennas needs to be more than or close to half the wavelength of the communication electromagnetic wave signal. A sufficient antenna spacing can ensure that the signals received by different antennas have spatial distinguishability. The wavelength of low-frequency communication is very long, reaching more than 1 km, and the antenna spacing close to half the wavelength (500 m) is unacceptable for general low-frequency communication systems. In addition, the number of antennas is also a key. The more the number of antennas, the better the effect of spatial anti-interference.

[0004] Therefore, how to place as many antennas as possible in a limited space and ensure that the received signals of these antennas have spatial distinguishability is a problem to be solved. SUMMARY

[0005] In view of the above defects or improvement needs of the prior art, the present application provides a low-frequency communication anti-interference method and system, which can integrate multiple low-frequency receiving antennas in a limited space and ensure that the received signals of these antennas have spatial distinguishability, thereby improving the effect of multi-antenna processing.

[0006] To achieve the above-mentioned purpose, according to the first aspect of the present application, a low-frequency communication anti-interference method is provided, comprising:

[0007] S1, receiving low-frequency signals in a preset time period through N electric antennas and M magnetic antennas; wherein the M magnetic antennas are placed perpendicular to each other, N≥1, M=2 or M=3;

[0008] S2, preprocessing the low-frequency signals received by the N electric antennas and the M magnetic antennas; wherein the preprocessing includes amplification, filtering and analog-to-digital conversion;

[0009] S3, determining a channel response h1 of the low-frequency communication signal and a channel response h2 of the low-frequency interference signal in the pre-processed low-frequency signal, and obtaining the low-frequency communication signal in the preset time period.

[0010] According to a second aspect of the present application, a low-frequency communication anti-interference system is provided, comprising:

[0011] N electric antennas and M magnetic antennas for simultaneously receiving low-frequency signals in a preset time period; wherein the M magnetic antennas are placed perpendicular to each other, N≥1, M=2 or M=3;

[0012] a receiving front end for pre-processing the low-frequency signals received by the N electric antennas and M magnetic antennas; wherein the pre-processing includes amplification, filtering and analog-to-digital conversion;

[0013] a multi-antenna receiving processing module for determining a channel response h1 of the low-frequency communication signal and a channel response h2 of the low-frequency interference signal in the pre-processed low-frequency signal, and obtaining the low-frequency communication signal in the preset time period.

[0014] According to a third aspect of the present application, an electronic device is provided, comprising: a computer readable storage medium and a processor;

[0015] the computer readable storage medium is configured to store executable instructions;

[0016] the processor is configured to read the executable instructions stored in the computer readable storage medium and execute the method according to the first aspect.

[0017] According to a fourth aspect of the present application, a computer readable storage medium is provided, characterized in that the computer readable storage medium stores computer instructions, and the computer instructions are configured to cause a processor to execute the method according to the first aspect.

[0018] Overall, compared with the prior art, the above technical solutions conceived by the present application can achieve the following beneficial effects:

[0019] The method provided by the present application uses electric antennas and magnetic antennas to receive low-frequency communication signals. Compared with the prior art which uses multiple electric antennas and requires a certain antenna spacing to ensure spatial resolution, the method provided by the present application has lower requirements for antenna spacing, so the antenna spacing can be set closer, thereby saving the space required for placing antennas, and the receiving end does not need a large space to receive low-frequency signals. Moreover, the present application uses two different antennas, which have different responses to near-field and far-field signals, and can provide better spatial resolution, and the multi-antenna processing effect is better. In addition, the number of electric antennas and magnetic antennas in the present application can be flexibly changed according to actual measurement requirements and space requirements. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 A low-frequency communication anti-interference method flow chart is provided for the embodiments of the present application.

[0021] Figure 2 A low-frequency communication anti-interference system structure diagram is provided for the embodiments of the present application. DETAILED DESCRIPTION

[0022] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0023] The embodiments of the present application provide a low-frequency communication anti-interference method, as shown in Figure 1 , comprising:

[0024] S1, receiving low-frequency signals in a preset time period through N electric antennas and M magnetic antennas simultaneously; wherein the M magnetic antennas are placed perpendicular to each other, N≥1, M=2 or M=3.

[0025] Specifically, the receiving principles of electric antennas and magnetic antennas are different, and they are respectively used to receive electric signals and magnetic signals in the air. For near-field and far-field signals, the receiving effects of the two kinds of antennas are different. Low-frequency communication signals are far-field signals, while low-frequency interference signals are near-field signals in many cases. The responses of electric antennas and magnetic antennas to near-field and far-field signals are different, thereby having spatial discrimination of signal reception.

[0026] The M magnetic antennas are placed perpendicular to each other. When M=2, the M magnetic antennas are placed perpendicular to each other in a two-dimensional space; when M=3, the M magnetic antennas are placed perpendicular to each other in a three-dimensional space.

[0027] The M magnetic antennas are placed perpendicular to each other in the horizontal plane, because the magnetic antennas themselves have a certain receiving directivity, and the perpendicular placement ensures that the magnetic antennas have spatial discrimination of signal reception.

[0028] S2, pre-processing the low-frequency signals (including low-frequency communication signals and low-frequency interference signals) received by the N electric antennas and the M magnetic antennas; wherein the pre-processing includes amplification, filtering and analog-to-digital conversion.

[0029] Specifically, the signals from the magnetic antennas and electric antennas (i.e. the signals received by the magnetic antennas and electric antennas) are pre-processed, and the pre-processing includes amplification, filtering and analog-to-digital conversion.

[0030] S3, determining a channel response h1 of the low-frequency communication signal and a channel response h2 of the low-frequency interference signal in the pre-processed low-frequency signal to obtain the low-frequency communication signal in the preset time period.

[0031] It can be understood that the above-mentioned channel refers to the channel between the transmitting end and the N electric antennas and the M magnetic antennas respectively.

[0032] Specifically, the pre-processed low-frequency signal is a digital signal after sampling and quantization, and signal processing is performed thereon. In the signal processing process, multi-antenna technology is used to suppress interference, and demodulation and decoding are performed. The communication data is restored to obtain the low-frequency communication signal after interference suppression.

[0033] The above-mentioned signal processing can adopt existing methods, such as mean square error (MMSE) estimation method, maximum likelihood (ML) estimation method and Kalman filter (KF) estimation method, etc. It can also adopt methods based on deep learning or machine learning, etc.

[0034] In order to improve the calculation accuracy and save the calculation resources, preferably, in step S3, R is calculated according to the formula R=pinv(H)r to obtain the low-frequency communication signal.

[0035] Wherein, the first row of R is the low-frequency communication signal in the preset time period, H=[h1, h2], pinv represents the generalized inverse calculation, r is a (N+M)*1-dimensional vector composed of the sampling points of the received signals of the N electric antennas and the M magnetic antennas in the preset time period; h1 and h2 are both (N+M)*1-dimensional vectors.

[0036] Specifically, the derivation process of the above-mentioned formula is as follows:

[0037] 1) Determine the channel response of the low-frequency communication signal, represented by vector h1, with the number of rows being N+M and the number of columns being 1. Wherein, the nth row element is the channel response of the low-frequency communication signal on the channel between the transmitting end and the kth electric antenna, n=[1, N]; the mth row element is the channel response of the low-frequency communication signal on the channel between the transmitting end and the mth magnetic antenna, m=[1, M].

[0038] Wherein, the existing method is used for channel response estimation of the low-frequency communication signal, and the embodiment of the application does not make a unique limitation on this. As an example, the channel response estimation method based on the known synchronization sequence can be used, that is, the synchronization sequence transmitted by the transmitting end in the preset time period is used for channel response estimation. The specific mathematical calculation method can adopt existing methods such as mean square error (MMSE) estimation method, maximum likelihood (ML) estimation method and Kalman filter (KF) estimation method. In addition, in addition to the channel response estimation method based on the known synchronization sequence, methods independent of the known sequence can also be used, such as blind estimation method for channel response estimation.

[0039] 2) Determine the channel response of the low-frequency interference signal, denoted by vector h2, the number of rows of h2 is N+M, and the number of columns is 1. Similarly, the nth row element is the channel response of the low-frequency interference signal on the channel between the transmitting end and the kth electric antenna, n=[1,N]; the mth row element is the channel response of the low-frequency interference signal on the channel between the transmitting end and the mth electric antenna, m=[1,M].

[0040] Wherein, the existing method is used for channel response estimation of low-frequency interference signal, and the embodiment of the application is not uniquely limited. For example, for single-frequency interference, the received signals of N electric antennas and M magnetic antennas are preprocessed, and then FFT processing is performed, and the FFT value of the frequency point of the single-frequency signal is taken as the channel response value of the low-frequency interference signal.

[0041] It can be understood that for burst interference (such as lightning interference) in the time domain, existing methods such as deep learning or machine learning can be used for channel response estimation, which will not be described here.

[0042] 3) Construct a matrix H=[h1 h2], and calculate R=pinv(H)r, wherein r is a (N+M)*1-dimensional vector composed of sampling points of the received signals (i.e. low-frequency signals) of N electric antennas and M magnetic antennas in the preset time period, and there is only one received signal sampling point for one antenna at one sampling time in the preset time period, and pinv represents a generalized inverse.

[0043] It can be understood that the number of rows of H is N+M, and the number of columns is 2, then the number of rows of pinv(H) is 2, and the number of columns is N+M, and the number of rows of r is N+M, and the number of columns is 1, therefore, the number of rows of R is 2, and the number of columns is 1, and since H=[h1 h2], then correspondingly, the first row of R is the low-frequency communication signal in the preset time period, and the second row of R is the low-frequency interference signal in the preset time period.

[0044] It can be understood that the more the number of antennas, the better the effect of spatial anti-interference. However, when expanding the number of electric antennas, the distance between them needs to be increased to ensure that the received signals of different electric antennas have spatial discrimination, so in actual use, the number of electric antennas can be appropriately selected according to the actual situation.

[0045] The low-frequency communication anti-interference system provided by the application is described below, and the low-frequency communication anti-interference system described below can be mutually corresponding with the low-frequency communication anti-interference method described above.

[0046] The embodiment of the application provides a low-frequency communication anti-interference system, which comprises:

[0047] N electric antennas and M magnetic antennas, used for simultaneously receiving low-frequency signals in a preset time period; wherein the M magnetic antennas are placed perpendicularly to each other, N≥1, M=2 or M=3;

[0048] a receiving front end, used for pre-processing the low-frequency signals received by the N electric antennas and the M magnetic antennas; wherein the pre-processing includes amplification, filtering and analog-to-digital conversion;

[0049] a multi-antenna receiving processing module, used for determining a channel response h1 of a low-frequency communication signal and a channel response h2 of a low-frequency interference signal in the pre-processed low-frequency signals, and calculating R according to a formula R=pinv(H)r to obtain the low-frequency communication signal in the preset time period;

[0050] wherein the first row of R is the low-frequency communication signal in the preset time period, H=[h1, h2], pinv represents a generalized inverse calculation, r is a (N+M)*1-dimensional vector composed of sampling points of the received signals of the N electric antennas and the M magnetic antennas in the preset time period; h1 and h2 are both (N+M)*1-dimensional vectors.

[0051] The system provided by the application is described below by taking N=1 and M=2 as an example.

[0052] The low-frequency communication system integrates three antennas, one of which is an electric antenna and the other two are magnetic antennas. The two magnetic antennas are placed perpendicularly to each other in a horizontal plane.

[0053] The signals from the magnetic antennas and the electric antenna are processed by the receiving front end, and the functions of the receiving front end include amplification, filtering and analog-to-digital conversion. The receiving front end outputs the digital signals quantized after sampling to the multi-antenna receiving processing module, which receives the sampling signals from the magnetic antennas and the electric antenna, performs signal processing, suppresses interference by using the multi-antenna technology in the signal processing process, and performs demodulation and decoding processing to restore the communication data, including:

[0054] 1) determining the channel response of the low-frequency communication signal, which is represented by a vector h1, the vector being 3 rows and 1 column, and the 3 rows one-to-one corresponding to the 3 receiving antennas, i.e. 1 electric antenna and 2 electric antennas;

[0055] 2) determining the channel response of the low-frequency interference signal, which is represented by a vector h2, the vector being 3 rows and 1 column, and similarly, the 3 rows one-to-one corresponding to the 3 receiving antennas;

[0056] 3) forming a matrix H=[h1, h2] of 3 rows and 2 columns;

[0057] 4) calculating R=pinv(H)r, wherein the 3*1 vector r is a vector composed of sampling points of the received signals of all the antennas in the same time period (i.e. the preset time period), and pinv represents a generalized inverse;

[0058] 5) take the first row of R to get the received signal sample point after inhibition, that is, to get the low-frequency communication signal in the time period.

[0059] Embodiments of the present application provide a low-frequency communication anti-interference system, comprising:

[0060] N electric antennas and M magnetic antennas, used for receiving low-frequency signals in a preset time period simultaneously; wherein the M magnetic antennas are placed perpendicular to each other, N≥1, M=2 or M=3;

[0061] a receiving front end, used for preprocessing the low-frequency signals received by the N electric antennas and the M magnetic antennas; wherein the preprocessing comprises amplification, filtering and analog-to-digital conversion;

[0062] a multi-antenna receiving processing module, used for determining a channel response h1 of a low-frequency communication signal and a channel response h2 of a low-frequency interference signal in the preprocessed low-frequency signals, so as to obtain the low-frequency communication signal in the preset time period.

[0063] Embodiments of the present application provide an electronic device, comprising: a computer readable storage medium and a processor;

[0064] The computer readable storage medium is used for storing executable instructions;

[0065] The processor is used for reading the executable instructions stored in the computer readable storage medium, and performing the method according to any one of the above embodiments.

[0066] Embodiments of the present application provide a computer readable storage medium, which stores computer instructions, and the computer instructions are used for making a processor execute the method according to any one of the above embodiments.

[0067] Those skilled in the art can easily understand that the above description is only the preferred embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A low frequency communication anti-jamming method, characterized in that, The method comprises: S1, receiving low-frequency signals in a preset period of time through N electric antennas and M magnetic antennas simultaneously; wherein the M magnetic antennas are placed perpendicular to each other, N≥1, M=2 or M=3; S2, pre-processing the low-frequency signals received by the N electric antennas and the M magnetic antennas; wherein the pre-processing comprises amplification, filtering and analog-to-digital conversion; S3, determining a channel response of the low-frequency communication signal in the pre-processed low-frequency signal and the low-frequency interference signal , obtaining the low-frequency communication signal in the preset time period; In step S3, the low-frequency communication signals in the preset period of time are obtained according to the formula R=pinv(H) r. wherein the first R is a low-frequency communication signal of the preset time period, , pinv represents a generalized inverse calculation, r is a sample point group of the received signals of the N electric antennas and the M magnetic antennas in the preset time period dimensional vector; and are all dimensional vectors.

2. The method of claim 1, wherein, In step S3, the channel response of the low frequency communication signal is estimated according to the pre-processed low frequency signal and the known synchronization sequence ; The known synchronization sequence is a low-frequency signal synchronously transmitted by the transmitting end.

3. The method of claim 1 or 2, wherein, In step S3, if the low-frequency interference signal is a single-frequency interference signal, then the FFT value of the frequency point of the single-frequency interference signal is taken as the channel response value of the low-frequency interference signal after FFT processing of the corresponding pre-processed low-frequency signal.

4. The method of claim 1, wherein, When M=2, the M magnetic antennas are placed perpendicular to each other in a two-dimensional space. When M=3, the M magnetic antennas are placed perpendicular to each other in a three-dimensional space.

5. A low frequency communication anti-jamming system, characterized in that, The method comprises: N electric antennas and M magnetic antennas for receiving low-frequency signals in a preset period of time simultaneously; wherein the M magnetic antennas are placed perpendicular to each other, N≥1, M=2 or M=3; A receiving front end for pre-processing the low-frequency signals received by the N electric antennas and the M magnetic antennas; wherein the pre-processing comprises amplification, filtering and analog-to-digital conversion; The multi-antenna receiving processing module is configured to determine the channel response of the low-frequency communication signal in the pre-processed low-frequency signal and the channel response of the low-frequency interference signal , and obtain the low-frequency communication signal in the preset time period. The low-frequency communication signals in the preset period of time are obtained according to the formula R=pinv(H) r. wherein the first column of R is the low frequency communication signal of the preset time period, pinv represents a generalized inverse calculation, r is an N*M matrix composed of sampling points of the received signals of the N electric antennas and the M magnetic antennas in the preset time period ; and are N*M matrices. ​ 6. An electronic device, comprising: The method comprises: A computer readable storage medium and a processor; The computer readable storage medium is used to store executable instructions; The processor is used to read the executable instructions stored in the computer readable storage medium, and execute the method as claimed in any one of claims 1-4.

7. A computer-readable storage medium, characterized in that, The computer readable storage medium stores computer instructions for causing the processor to execute the method as claimed in any one of claims 1-4.

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