An algorithm for removing high-power noise interference based on vortex waves

Abstract

This invention discloses an algorithm for removing high-power noise interference based on vortex waves, belonging to the field of signal processing technology. In this invention, the transmitted signal is a vortex wave signal. At the receiving end, an antenna array (number of array elements N≥2) receives the signal containing high-power noise interference. The received mixed signal is then subjected to vortex wave-based noise reduction processing. The vortex wave noise reduction principle is as follows: The average amplitude or the average of the maximum and minimum amplitude values ​​and the average phase of the electric field of N echo signals are taken. Then, the average amplitude and phase values ​​are combined to form a noise reduction electric field. Alternatively, one echo signal from the N echo signals can be arbitrarily selected, and the noise reduction electric field is subtracted from that echo signal. Compared with existing plane wave-based signal processing algorithms, this invention can extract vortex wave signals under low signal-to-noise ratio conditions, which is beneficial for improving the anti-interference capability in the field of signal processing and has significant practical application value.

Description

Technical Field

[0001] This invention belongs to the field of signal processing, specifically relating to an algorithm for removing high-power noise interference based on vortex waves. Background Technology

[0002] Vortex waves carry orbital angular momentum Where l is the mode number of the vortex wave. It is the azimuth angle. The phase of a vortex wave on a plane perpendicular to the transmission direction has a unique distribution characteristic, that is, the phase of the electric field changes by a factor of 2πl around the circumference of the transmission direction. Moreover, vortex waves carrying different modes are orthogonal to each other. The waveform characteristics and orthogonality of vortex waves make them have great application potential in radar, communication and other fields. The waveform characteristics of vortex waves can make them have higher resolution when detecting targets, see K. Liu, Y. Cheng, Y. Gao, X. Li, Y. Qin, and H. Wang, “Super-resolution radar imaging based on experimental OAM beams,” Applied Physics Letters, 2017, 110(16), art. no. 164102. In the field of communication detection, vortex waves of different modes can carry different information in the same frequency band, thereby increasing the spectral capacity of communication systems (see J. Wang, J. Yang, IMFazal, N. Ahmed, Y. Yan, H. Huang, Y. Ren, Y. Yue, S. Dolinar, M. Tur, and A.E. Willner, “Terabit free-space data transmission employing orbital angular momentum multiplexing,” Nature Photonics, 2012, 6(7), 488–496). In the above applications, the signal-to-noise ratio (SNR) of vortex waves should be sufficiently high, at least comparable to that of existing plane wave-based signal processing. However, can the waveform characteristics of vortex waves still be maintained under high-power plane wave interference? If the waveform characteristics of vortex waves can still be maintained under low SNR conditions, then applying vortex waves to the field of signal processing can greatly improve the SNR of signal processing and enhance the performance of signal processing systems. Summary of the Invention

[0003] To address the waveform characteristics of vortex waves and the question of whether they can maintain their waveform characteristics under high-power plane wave interference, this invention provides an algorithm. This algorithm verifies that vortex waves can maintain their waveform characteristics even under high-power plane wave interference and can effectively remove high-power noise interference, thereby improving the signal-to-noise ratio.

[0004] An algorithm for removing high-power noise interference based on vortex waves, characterized by:

[0005] The electromagnetic wave of the transmitted signal is a vortex wave;

[0006] The number of antenna arrays that receive electromagnetic wave signals is N, where N≥2;

[0007] The electric field processor can acquire the amplitude and phase information of the received electric field;

[0008] The noise denoiser is capable of performing electric field level calculations on the received signal.

[0009] The electric field processor (30) takes the amplitude of the electric field of the N signals received by the antenna array (20) and processes the amplitude of the electric field of the N signals. The processing method is as follows: (1) Take the average value of the amplitude of the N electric fields, and the amplitude of the electric field of the processed output signal is (2) The average of the maximum and minimum values ​​of the N-channel electric field amplitudes is taken, and the amplitude of the electric field of the processed output signal is...

[0010] The electric field processor (30) takes the phase of the N-channel signal electric field received by the antenna array (20) and processes the phase of the N-channel signal electric field. The processing method is as follows: the average value of the phase of the N-channel electric field is taken, and the electric field phase of the processed output signal is...

[0011] The noise reduction unit (40) is capable of performing a subtraction operation on the electric field, subtracting the electric field output by the electric field processor (30) from any one of the N received signals. or The output electric field of the noise denoiser (40) is E io =E i -E a Output electric field E io It refers to the useful signal after removing high-power noise interference, and its effect on the output electric field E. io Performing conventional signal processing can increase the signal-to-noise ratio after signal processing and improve the performance of the signal processing system.

[0012] The present invention has the following beneficial effects:

[0013] This method can effectively remove noise interference in low signal-to-noise ratio signals, and can effectively extract useful vortex wave signals even when the intensity ratio between the signal and noise differs by more than 100 times. It can significantly improve the signal-to-noise ratio after signal processing and enhance system performance. Attached Figure Description

[0014] Figure 1 This is a structural diagram of a specific embodiment;

[0015] Figure 2 The phase distribution diagram of the vortex wave;

[0016] Figure 3 The phase distribution diagram of the synthesized wave;

[0017] Figure 4 The phase distribution diagram for noise removal using method (1);

[0018] Figure 5 The phase distribution diagram for noise removal using method (2) is shown. Detailed Implementation

[0019] A vortex wave of mode 1 is generated, and a plane wave electric field with an intensity 100 times that of the vortex wave is added to the vortex wave. The vortex wave and the plane wave together constitute a composite wave. According to the method provided by this invention, the vortex wave with an intensity of 1 is extracted from the composite wave. The specific implementation process is as follows: Figure 1 As shown.

[0020] The vortex wave of mode 1 carries a phase factor The phase distribution diagram of the vortex wave in mode 1 is as follows: Figure 2 As shown, its phase changes by 2π on a circle.

[0021] The phase distribution of the composite wave formed by adding a vortex wave and a plane wave with 100 times the intensity is as follows: Figure 3 As shown, the phase distribution of the synthesized wave no longer exhibits vortex wave characteristics. The phase distribution on this plane exhibits plane wave characteristics, meaning that the phase is essentially a fixed value on this plane.

[0022] The phase of the electric field of the 8 signals received by the antenna array (20) is obtained by the electric field processor (30), and the average phase of the 8 electric fields is taken. The electric field phase of the processed output signal is:

[0023] Method (1): The electric field processor (30) is used to obtain the amplitude of the electric field of the 8 signals received by the antenna array (20), and the average value of the 8 electric field amplitudes is taken. The amplitude of the processed output electric field is The first received electric field is subtracted using a noise denoiser (40). The output electric field of the noise denoiser (40) is E 1o=E1-E a Output electric field E 1o The phase distribution diagram of the vortex wave after removing high-power noise interference is as follows: Figure 4 As shown. It can be observed that the electric field E 1o The phase distribution is typical of vortex wave phase distribution characteristics, indicating that the vortex wave was completely extracted from plane wave noise interference with an amplitude 100 times stronger than its own.

[0024] Method (2): The electric field amplitude is taken as the average of the maximum and minimum values. The amplitude of the processed output electric field is... The first received electric field is subtracted using a noise denoiser (40). The output electric field of the noise denoiser (40) is E 1o =E1-E a Output electric field E 1o The phase distribution diagram of the vortex wave after removing high-power noise interference is as follows: Figure 5 As shown. It can be observed that the electric field E 1o The phase distribution is typical of vortex wave phase distribution characteristics, indicating that the vortex wave was completely extracted from plane wave noise interference with an amplitude 100 times stronger than its own. Figure 4 and Figure 5 The results demonstrate that both methods for processing the electric field amplitude are effective.

[0025] The above is merely a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An algorithm for removing high-power noise interference based on vortex waves, characterized in that: The electromagnetic wave (10) that transmits the signal is a vortex wave; The number of antenna arrays (20) that receive electromagnetic wave signals is N, where N≥2; The electric field processor (30) can acquire the amplitude and phase information of the received electric field; The electric field processor (30) takes the amplitude of the electric field of the N signals received by the antenna array (20) and processes the amplitude of the electric field of the N signals. The processing method is as follows: (1) Take the average value of the amplitude of the N electric fields. The amplitude of the output signal electric field after processing is 1. (2) The average of the maximum and minimum values ​​of the N-channel electric field amplitudes is taken, and the amplitude of the processed output signal electric field is . ; The denoiser (40) is capable of performing electric field level calculations on the received signal. The noise reduction unit (40) is capable of performing a subtraction operation on the electric field, subtracting the electric field output by the electric field processor (30) from any one of the N received signals. or That is, the output electric field of the noise denoiser (40) is E io = E i -E a , Output electric field E io It refers to the useful signal after removing high-power noise interference, and its effect on the output electric field. E io Performing conventional signal processing can increase the signal-to-noise ratio after signal processing and improve the performance of the signal processing system.

2. The algorithm for removing high-power noise interference based on vortex waves according to claim 1, characterized in that: The electric field processor (30) receives the phases of the N signal electric fields from the antenna array (20) and processes them. The processing method is to take the average value of the phases of the N signal electric fields, and the electric field phase of the processed output signal is... .

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