Communication anti-interference method and device based on waveform orthogonality

Abstract

This invention discloses a communication anti-interference method and apparatus based on waveform orthogonality, relating to the field of signal processing technology. The method includes: acquiring a first signal modulated at a transmitting end; acquiring a second signal received at a receiving end; wherein the second signal is formed by superimposing an interference signal and a noise signal onto the first signal, the interference signal being a signal existing in space, and the noise signal being a signal existing in the environment; demodulating and deciding on the second signal to acquire an interference waveform in the second signal; generating an orthogonal subspace of the interference waveform based on the interference waveform; projecting the second signal onto the orthogonal subspace to acquire an interference suppression signal; and demodulating the suppressed interference signal to acquire an original symbol sequence, the original symbol sequence being formed by the second signal suppressing the interference signal. This application can effectively suppress interference signals.

Description

Technical Field

[0001] This invention belongs to the field of signal processing technology, specifically relating to a communication anti-interference method and apparatus based on waveform orthogonality. Background Technology

[0002] With the rapid development of digital wireless communication, the contradiction between limited spectrum resources and the rapidly increasing number of wireless communication users is becoming increasingly acute. Communication technology development has been constantly exploring how to utilize the spectrum more effectively. However, sharing the spectrum also greatly increases the possibility of mutual interference between users. When the frequencies and bandwidths of two signals overlap, interference between the two signals is difficult to overcome. Therefore, interference suppression of co-channel signals is particularly important.

[0003] In related technologies, existing interference suppression techniques typically require adaptive filtering or multi-dimensional domain anti-interference techniques. Adaptive filtering typically employs descent algorithms and state-space models, adapting to the dynamic characteristics of interference and channel changes. It converges to the desired signal under different constraint criteria, obtaining the most weighted filter coefficients. However, this technique is computationally complex and requires prior knowledge of the signal. Multi-dimensional domain anti-interference methods utilize the characteristics of the signal and interference in various domains, such as time, frequency, spatial, polarization, and waveform domains, to suppress interference by exploiting the information differences between the target and interference signals in any of these domains. Existing time-domain interference suppression methods generally use adaptive filters to generate nulls at the interference points. If the threshold is not properly selected, this method of directly suppressing time-domain nulls can introduce additional interference, affecting signal synchronization and severely damaging system performance. Frequency-domain elimination suppression methods are the simplest and most effective suppression methods. They convert the FFT signal from the time domain to the frequency domain and use a synchronization process to eliminate the spectrum. However, the threshold setting significantly impacts interference suppression performance.

[0004] Therefore, there is an urgent need for a method to suppress interference signals quickly and effectively. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention provides a communication anti-interference method and apparatus based on waveform orthogonality. The technical problem to be solved by this invention is achieved through the following technical solution:

[0006] In a first aspect, this application provides a communication anti-interference method based on waveform orthogonality, comprising:

[0007] Acquire the first signal modulated by the transmitting end;

[0008] The receiver acquires the second signal received by the receiver; wherein the second signal is formed by superimposing the first signal with an interference signal and a noise signal, the interference signal being a signal existing in space, and the noise signal being a signal existing in the environment;

[0009] Demodulate and decide on the second signal to obtain the interference waveform in the second signal;

[0010] Based on the interference waveform, an orthogonal subspace of the interference waveform is generated;

[0011] The second signal is projected onto an orthogonal subspace to obtain the interference suppression signal;

[0012] The interference suppression signal is demodulated to obtain the original symbol sequence, which is formed by the second signal interference suppression signal.

[0013] Secondly, this application also provides a communication anti-interference device based on waveform orthogonality, applied to the communication anti-interference method based on waveform orthogonality provided in this application. The device includes:

[0014] The first acquisition module is used to acquire the first signal modulated by the transmitting end;

[0015] The second acquisition module is used to acquire the second signal received by the receiving end; wherein the second signal is formed by superimposing the first signal with an interference signal and a noise signal, the interference signal being a signal existing in space, and the noise signal being a signal existing in the environment;

[0016] The demodulation decision module is used to demodulate and decide on the second signal to obtain the interference waveform in the second signal;

[0017] The first generation module is used to generate an orthogonal subspace of the interference waveform based on the interference waveform;

[0018] The second generation module is used to project the second signal into the orthogonal subspace to obtain the interference suppression signal;

[0019] The third generation module is used to demodulate the suppressed interference signal to obtain the original symbol sequence, which is formed by the second signal suppressed interference signal.

[0020] The beneficial effects of this invention are:

[0021] This invention provides a communication anti-interference method and apparatus based on waveform orthogonality. It adopts an orthogonal subspace interference suppression method based on eigenvalue decomposition. By recovering the high-power interference waveform existing in the space, the orthogonal subspace of the interference is obtained in the interference waveform domain in a waveform orthogonal manner for interference suppression. In addition, since the interference waveform has been recovered, the prior knowledge of the interference waveform has been obtained, so the subspace of the interference can be accurately obtained and the interference can be fully suppressed.

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] Figure 1 This is a flowchart of a communication anti-interference method based on waveform orthogonality provided in an embodiment of the present invention;

[0024] Figure 2 This is another flowchart of the communication anti-interference method based on waveform orthogonality provided in the embodiments of the present invention;

[0025] Figure 3 This is a schematic diagram of a communication anti-interference device based on waveform orthogonality provided in an embodiment of the present invention;

[0026] Figure 4 This is a simulation diagram of a communication anti-interference method based on waveform orthogonality provided in an embodiment of the present invention;

[0027] Figure 5 This is another simulation diagram of the communication anti-interference method based on waveform orthogonality provided in the embodiments of the present invention;

[0028] Figure 6 This is another simulation diagram of the communication anti-interference method based on waveform orthogonality provided in the embodiments of the present invention;

[0029] Figure 7 This is another simulation diagram of the communication anti-interference method based on waveform orthogonality provided in the embodiments of the present invention;

[0030] Figure 8 This is another simulation diagram of the communication anti-interference method based on waveform orthogonality provided in the embodiments of the present invention;

[0031] Figure 9 This is another simulation diagram of the communication anti-interference method based on waveform orthogonality provided in the embodiments of the present invention. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0033] See Figure 1 , Figure 1 This is a flowchart of a communication anti-interference method based on waveform orthogonality provided in an embodiment of the present invention. The communication anti-interference method based on waveform orthogonality provided in this application includes:

[0034] S101. Obtain the first signal modulated by the transmitting end;

[0035] S102. Obtain the second signal received by the receiving end; wherein the second signal is formed by superimposing the first signal with an interference signal and a noise signal, the interference signal being a signal existing in space, and the noise signal being a signal existing in the environment;

[0036] S103. Demodulate and decide on the second signal to obtain the interference waveform in the second signal;

[0037] S104. Based on the interference waveform, generate the orthogonal subspace of the interference waveform;

[0038] S105. Project the second signal onto the orthogonal subspace to obtain the interference suppression signal;

[0039] S106. Demodulate the suppressed interference signal to obtain the original symbol sequence, which is formed by the second signal suppressed interference signal.

[0040] For details, please refer to [link / reference]. Figure 1 As shown, the communication anti-interference method based on waveform orthogonality provided in this embodiment obtains the second signal of the suppressed interference signal through the following six steps to overcome the interference of the interference signal. For detailed process, please refer to the following.

[0041] S101. In this step, the first signal modulated by the transmitting end is obtained; wherein, the first signal does not have interference signals and noise signals superimposed in the space;

[0042] S102. In this step, the second signal received by the receiving end is obtained; wherein, the second signal is formed by superimposing the first signal obtained in step S101 with interference signal and noise signal. It can also be understood that the second signal received in this step contains some interference signal and noise signal that have no effect or even affect the second signal. The interference signal is a signal that exists in space, and the noise signal is a signal that exists in the environment. The interference signal and noise signal are unavoidable signals, but they can be suppressed by the following methods.

[0043] S103. In this step, the second signal obtained in step S102 is demodulated and a decision is made to obtain the interference waveform in the second signal; optionally, the obtained interference waveform is completely consistent with the original interference waveform in space except that the amplitude is the same.

[0044] S104. Based on the interference waveform obtained in step S103, generate an orthogonal subspace of the interference waveform.

[0045] S105. Project the second signal obtained in step S102 onto the orthogonal subspace obtained in step S104 to obtain the interference suppression signal;

[0046] S106. Demodulate the suppressed interference signal obtained in step S105 to obtain the original symbol sequence. The original symbol sequence is the second signal suppressed interference signal. Alternatively, the second signal of the suppressed interference signal can be understood as the first signal with noise signal superimposed.

[0047] Through the above steps, an orthogonal subspace interference suppression method based on eigenvalue decomposition is adopted. By recovering the high-power interference waveform in the space, the orthogonal subspace of the interference is obtained in the interference waveform domain in a waveform orthogonal manner for interference suppression. In addition, since the interference waveform has been recovered, the prior knowledge of the interference waveform has been obtained, so the interference subspace can be accurately obtained and the interference can be fully suppressed.

[0048] See Figure 2 , Figure 2 This is another flowchart of a communication anti-interference method based on waveform orthogonality provided in an embodiment of the present invention. In an optional embodiment of this application, the method for obtaining the interference signal is as follows:

[0049] Obtain the binary bit sequence I generated at the interference end bit For bit sequence I bit Perform serial-to-parallel conversion, that is, convert the bit sequence I... bit The odd and even sequences are respectively subjected to 16-bit spread spectrum modulation to obtain the first spread spectrum signal intI. spread Second spread spectrum signal intQ spread The first spread spectrum signal intI is respectively... spread Modulation and modulation of the second spread spectrum signal intQ spread Modulation is performed to obtain the first modulation signal I. QPSK,i = [1+j,1-j,-1-j,-1+j], where 1+i is the real part of the first modulated signal and j is the imaginary part of the first modulated signal;

[0050] The first modulated signal is passed through a root-raised cosine filter, and N points are inserted into each symbol of the first modulated signal to obtain the interference signal I = [i1, i2, ..., i N ], where i is the value of the interference signal after discrete sampling, and N is the number of points of the interference signal after discrete sampling.

[0051] For details, please refer to [link / reference]. Figure 2 As shown, in this embodiment, the baseband QPSK interference signal I = [i1, i2, ..., i] present in space is obtained. N ];

[0052] First, obtain the binary bit sequence I generated by the interference end. bit For bit sequence I bit The odd and even sequences are respectively subjected to 16-bit spread spectrum modulation to obtain the first spread spectrum signal intI. spread Second spread spectrum signal intQ spread For the first spread spectrum signal intI spread Perform I-channel BPSK modulation on the second spread spectrum signal intQ. spreadQ-channel BPSK modulation is performed to obtain the first QPSK modulation signal I. QPSK,i = [1+j, 1-j, -1-j, -1+j];

[0053] Secondly, the first modulation signal I QPSK,i The first modulation signal I is filtered by a root-raised cosine filter. QPSK,i Insert NN points into each symbol to obtain the interference signal I = [i1, i2, ..., i N Optionally, a root-raised cosine filter is used to reduce crosstalk between symbols in the first modulation signal.

[0054] It should be noted that for the first modulation signal I QPSK,i N points are inserted into each symbol in the code. N can be multiple values, which are not limited in this application.

[0055] Please continue to refer to Figure 2 As shown, in an optional embodiment of this application, the detailed process of obtaining the modulated first signal at the transmitting end in step S102 is as follows:

[0056] Obtain the binary bit stream S generated by the sending end bit For bitstream S bit Perform serial-to-parallel conversion, that is, convert the bit stream S bit The odd and even sequences are respectively subjected to 32-bit spread spectrum modulation to obtain the third spread spectrum signal sigI. spread and the fourth spread spectrum signal sigQ spread The third and fourth spread spectrum signals are modulated respectively to obtain the second modulated signal S. QPSK,i = [1+j,1-j,-1-j,-1+j], where 1+i is the real part of the second modulation signal and j is the imaginary part of the second modulation signal;

[0057] The second modulated signal is passed through a root-raised cosine filter, and four points are interpolated into each symbol of the second modulated signal to obtain the first signal S = [s1, s2, ..., s]. M ], where S is the value of the first signal after discrete sampling, and M is the number of points of the first signal after discrete sampling.

[0058] For details, please refer to [link / reference]. Figure 2 As shown, in this embodiment, the first signal S = [s1, s2, ..., s] of the transmitting end baseband QPSK is obtained. M ];

[0059] First, obtain the binary bit stream S generated by the sending end. bit For bitstream S bit The odd and even sequences are respectively subjected to 32-bit spread spectrum modulation to obtain the third spread spectrum signal sigI.spread and the fourth spread spectrum signal sigQ spread The third spread spectrum signal is modulated using I-channel BPSK, and the fourth spread spectrum signal is modulated using Q-channel BPSK to obtain the second QPSK modulated signal S. QPSK,i = [1+j, 1-j, -1-j, -1+j];

[0060] Secondly, the second modulation signal S QPSK,i The second modulation signal S is filtered by a root-raised cosine filter. QPSK,i The first signal S = [s1, s2, ..., s] is obtained by interpolating 4 points within each symbol. M Optionally, a root-raised cosine filter is used to reduce crosstalk between symbols in the first modulation signal.

[0061] Please continue to refer to Figure 2 As shown, in an optional embodiment of this application, the first signal is superimposed with the interference signal and the noise signal to obtain the second signal Y = [y1, y2, ..., y]. N ], where y is the value of the point after discrete sampling of the second signal, and N is the number of points after discrete sampling of the second signal;

[0062] The first signal and the interference signal are at least partially superimposed, and the superimposed portion is located at least one of the beginning, middle or end portion of the first signal.

[0063] For details, please refer to [link / reference]. Figure 2 As shown, in this embodiment, the first signal is superimposed with the interference signal and the noise signal, wherein the superposition expression of the first signal and the interference signal is A = [a1, a2, ..., a...]. N Because the sequence length of the interference signal is greater than that of the first signal, and the first signal is sent intermittently, there may be partial superposition between the first signal and the interference signal. Furthermore, this superposition may not necessarily occur at the beginning of the first signal. For example, A1 = [a1, a2, ..., a...]. p-1 ] and A3 = [a p+M+1 ,a p+M+2 ,…,a N The value in A2 only includes interference signals, while A2 = [a p ,a p+1 ,…,a p+M The signal in the image is the superimposed signal of the interference signal, and this superimposed signal is located in the middle part of the first signal.

[0064] It should be noted that the noise signal is band-limited noise, meaning it has the same bandwidth as the first signal.

[0065] Please continue to refer to Figure 2As shown, in an optional embodiment of this application, the detailed process of demodulating and determining the second signal in step S103 to obtain the interference waveform in the second signal is as follows:

[0066] The second signal Y = [y1, y2, ..., y N After low-pass filtering, the filtered signal Y is obtained. de For the filtered signal Y de The processed signal Y is obtained by downsampling the symbol rate of the interference signal. de_s Hard decision is made on the real part of the processed signal. When the real part of the processed signal is real(Y) de_s,i If )≥0, then the hard decision result is 1; when the real part of the processed signal real(Y) is 1, then the hard decision result is 1. de_s,i If ) < 0, then the hard decision result is -1, and the first bipolar signal is obtained from the decision result of the real part of the processed signal; a hard decision is performed on the imaginary part of the processed signal, and when the imaginary part of the processed signal, imag(Y) < 0, the result is -1. de_s,i If )≥0, then the hard decision result is 1; when the imaginary part of the processed signal, imag(Y)≥0, the hard decision result is 1. de_s,i If ) < 0, then the hard decision result is -1. The second bipolar signal is obtained from the decision result of the imaginary part of the processed signal; then the first bipolar signal and the second bipolar signal are subjected to root raised cosine shaping to obtain the information sequence [b1, b2, ... b] of the interference waveform in the second signal. l ], where b i = [1+j, 1-j, -1+j, -1-j], interpolate the information sequence of the interference waveform to obtain the interference waveform Ir = [ir1, ir2, ..., ir] in the second signal. N ]; where b is the information sequence of the interference waveform, and in 1+j, 1 is the real part and j is the imaginary part.

[0067] For details, please refer to [link / reference]. Figure 2 As shown, in this embodiment, it is necessary to recover the high-power interference waveform present in the space, that is, the information sequence of the recovered interference waveform [b1, b2, ... bb l The interference waveform is identical to the waveform of the interference signal in space except for the amplitude. By obtaining the interference waveform, it is necessary to further obtain the orthogonal subspace of the interference in the interference waveform domain using the waveform orthogonality method to suppress the interference, thereby suppressing the interference signal in the second signal and avoiding the influence of the interference signal.

[0068] Please continue to refer to Figure 2 As shown, in an optional embodiment of this application, the detailed process of generating the orthogonal subspace of the interference waveform based on the interference waveform in step S104 is as follows:

[0069] Based on the interference waveform, obtain the autocorrelation matrix R of the interference waveform.XX =Ir H ·Ir; where Ir H This is the conjugate transpose of the interference waveform Ir;

[0070] Based on the interference waveform, obtain the projected symbol vector. Set the values ​​of the first to the Nth symbol vector in the symbol vector to 0;

[0071] code vector Ir DP Combined into a first signal matrix Ir with each column having a size of t. shape ,

[0072] Where t is the size of the projected feature vector;

[0073] The unintegrated signal matrix Ir shape The symbol vector Ir in DP Placed as the second signal matrix Ir left ;

[0074] Based on the autocorrelation matrix R of the interference waveform XX Generate the first signal matrix Ir shape The autocorrelation matrix and the second signal matrix Ir left The autocorrelation matrix is ​​obtained, and eigenvalue decomposition is performed on each column of the signal in the autocorrelation matrix to obtain the orthogonal subspace Q of the interference waveform. ND Its expression is:

[0075] Among them, Q D The dominant eigenvector matrix is ​​Q. ND The non-dominant eigenvector matrix, where Λ is the eigenvalue matrix. D As the dominant eigenvalue matrix, Λ ND Q is a non-dominant eigenvalue matrix, and Q is an eigenvector matrix. H It is the conjugate transpose of the eigenvector matrix;

[0076] For details, please refer to [link / reference]. Figure 2 As shown, in this embodiment, firstly, based on the interference waveform, the autocorrelation matrix R of the interference waveform is obtained. XX The autocorrelation matrix of the interference waveform is obtained by multiplying the interference waveform by its conjugate transpose; secondly, based on the interference waveform, the projected symbol vector in the interference waveform is obtained. Given that the initial part of the interference waveform may be superimposed interference signals, the values ​​of the first to the Nth symbol vectors in the projected symbol vector are set to 0, which also facilitates subsequent calculations; secondly, the symbol vector Ir obtained above is... DP Combined into a first signal matrix Ir with each column having a size of t.shape There are still some symbol vectors that are not large enough to form a column of size t. These remaining symbol vectors are used to form the second signal matrix Ir. left The size of the second signal matrix is ​​length(Ir left )×1; secondly, based on the autocorrelation matrix R of the interference waveform XX First signal matrix Ir shape Second signal matrix Ir left Generate the autocorrelation matrix of the first signal matrix and the autocorrelation matrix of the second signal, and perform autocorrelation analysis on each column of the autocorrelation matrix for the signal ir. DP,i Eigenvalue decomposition is performed to obtain the orthogonal subspace Q of the interference waveform. ND The expression for eigenvalue decomposition is: The dominant space size is 1, Q D Given a t×1 matrix, the orthogonal subspace Q of the obtained interference waveform is... ND Let t be a matrix of t×(t-1), where t can be 32, 64, 128, 256, etc. This application does not impose any restrictions. Through the above steps, the orthogonal subspace of the interference is obtained by using waveform orthogonality.

[0077] Please continue to refer to Figure 2 As shown, in an optional embodiment of this application, the specific process of projecting the second signal into the orthogonal subspace to obtain the interference suppression signal in step S105 is as follows:

[0078] Obtain the first signal matrix Ir shape Each column of signals ir DP,i With the second signal matrix Ir left Projection matrix of the signal orthogonal subspace in Where I is the identity matrix;

[0079] Based on the first signal matrix Ir shape Second signal matrix Ir left And the second signal Y superimposed with the interfered symbols DP =[y NN+1 ,…,y NN+M ], obtain the third signal matrix Y shape and the fourth signal matrix Y left ,in,

[0080] The third signal matrix Y shape and the fourth signal matrix Y left Projection matrix P to the corresponding column i Obtain the multi-column recovery signal vector x DP,i =P i y DP,i ;

[0081] The multiple recovered signal vectors are integrated into an interference suppression signal X.

[0082] For details, please refer to [link / reference]. Figure 2 As shown, in this embodiment, firstly, the projection matrix P of the orthogonal subspace is obtained. i Based on the first signal matrix Ir shape Each column of signals and the second signal matrix Ir left The signals in the matrix are used to construct the projection matrix of the orthogonal subspace; secondly, the third information matrix Y is obtained. shape and the fourth information matrix Y left Based on the first signal matrix Ir shape Second signal matrix Ir left And the second signal Y superimposed with the interfered symbols DP Finally, the third signal matrix Y... shape and the fourth signal matrix Y left Projection matrix P to the corresponding column i Obtain the multi-column recovery signal vector x DP,i =P i y DP,i The multiple recovered signal vectors are integrated into a single suppressed signal X. Through the above steps, the suppressed signal is obtained, and the suppressed signal is then QPSK demodulated to obtain a binary sequence, which is the suppressed interference signal in the second signal. The above method can effectively suppress interference signals, and the effect of suppressing interference signals is good.

[0083] Based on the same inventive concept, please refer to Figure 3 , Figure 3 This is a schematic diagram of a communication anti-interference device based on waveform orthogonality provided in an embodiment of the present invention. This application also provides a communication anti-interference device based on waveform orthogonality, applied to the communication anti-interference method based on waveform orthogonality provided in the above embodiments. The device includes:

[0084] The first acquisition module 201 is used to acquire the first signal modulated by the transmitting end;

[0085] The second acquisition module 202 is used to acquire the second signal received by the receiving end; wherein the second signal is formed by superimposing the first signal with an interference signal and a noise signal, the interference signal being a signal existing in space, and the noise signal being a signal existing in the environment;

[0086] The demodulation decision module 203 is used to perform demodulation decision on the second signal and obtain the interference waveform in the second signal;

[0087] The first generation module 204 is used to generate an orthogonal subspace of the interference waveform based on the interference waveform;

[0088] The second generation module 205 is used to project the second signal onto the orthogonal subspace to obtain the interference suppression signal;

[0089] The third generation module 206 is used to demodulate the suppressed interference signal to obtain the original symbol sequence, which is formed by the second signal suppressed interference signal.

[0090] For details, please refer to [link / reference]. Figure 3 As shown, in this embodiment, the first acquisition module 201 acquires the first signal, the second acquisition module 202 acquires the second signal, the demodulation decision module 203 acquires the interference waveform in the second signal, the first generation module 204 generates an orthogonal subspace, the second generation module 205 generates an interference suppression signal, and the third generation module 206 acquires the signal after the second signal suppresses the interference signal. The device in this embodiment is simple and achieves good interference suppression effect.

[0091] In an optional embodiment of this application, the above method is verified by simulation. In the simulation experiment, the signal sampling frequency is Fs = 800kHz, the symbol rate is bitRate = 200kHz, and the signal bandwidth is B. S =100kHz. Simulation experiments were conducted to discuss four scenarios where the interference signal bandwidth accounts for 10%, 25%, and 100% of the signal bandwidth, respectively. The corresponding interference signal bandwidths are B. I =10kHz, 25kHz, 100kHz, then the corresponding number of symbol interpolation points is NN = 40, 16, 4.

[0092] See Figure 4 and Figure 5 , Figure 4 This is a simulation diagram of a communication anti-interference method based on waveform orthogonality provided in an embodiment of the present invention. Figure 5 This is another simulation diagram of the communication anti-interference method based on waveform orthogonality provided in the embodiments of the present invention. In one embodiment of this application, when the interference signal is a narrowband interference signal and the bandwidth of the interference signal accounts for 1 / 10 of the bandwidth of the second signal, after simulation experiments, the waveform of the interference signal can be completely recovered, effectively suppressing the interference signal and obtaining the ideal interference-free second signal.

[0093] See Figure 6 and Figure 7 , Figure 6 This is another simulation diagram of the communication anti-interference method based on waveform orthogonality provided in the embodiments of the present invention. Figure 7This is another simulation diagram of the communication anti-interference method based on waveform orthogonality provided in the embodiment of the present invention. In one embodiment of this application, when the interference signal is a narrowband interference signal and the bandwidth of the interference signal accounts for 1 / 4 of the bandwidth of the second signal, the interference signal waveform can still be effectively recovered after simulation experiment, so as to effectively suppress the interference signal and obtain a better second signal without interference.

[0094] See Figure 8 and Figure 9 , Figure 8 This is another simulation diagram of the communication anti-interference method based on waveform orthogonality provided in the embodiments of the present invention. Figure 9 This is another simulation diagram of the communication anti-interference method based on waveform orthogonality provided in the embodiments of the present invention. In an optional embodiment of this application, when the interference signal is a full-band interference signal, the interference signal bandwidth is equal to the second signal bandwidth; after the reverse experiment, good anti-interference performance can still be achieved.

[0095] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A communication anti-interference method based on waveform orthogonality, characterized in that, include: Acquire the first signal modulated by the transmitting end; Acquire a second signal received by the receiving end; wherein the second signal is formed by superimposing an interference signal and a noise signal on the first signal, the interference signal being a signal existing in space, and the noise signal being a signal existing in the environment; Demodulate and determine the second signal to obtain the interference waveform in the second signal; including: demodulating the second signal... After low-pass filtering, the filtered signal is obtained. , N The number of points after discretizing the second signal is used to define the filtered signal. The processed signal is obtained by downsampling the symbol rate of the interference signal. A hard decision is made on the real part of the processed signal; when the real part of the processed signal... If the real part of the processed signal is 1, then the hard decision result is 1. If the hard decision result is -1, the first bipolar signal is obtained from the decision result of the real part of the processed signal; a hard decision is performed on the imaginary part of the processed signal, and when the imaginary part of the processed signal... If the imaginary part of the processed signal is true, the hard decision result is 1; If the hard decision result is -1, the second bipolar signal is obtained from the decision result of the imaginary part of the processed signal; then the first bipolar signal and the second bipolar signal are subjected to root raised cosine shaping to obtain the information sequence of the interference waveform in the second signal. ,in, The information sequence of the interference waveform is interpolated to obtain the interference waveform in the second signal. ;in, b For the information sequence of the interference waveform, 1+ j In the diagram, 1 represents the real part. j It is the imaginary part; Based on the interference waveform, an orthogonal subspace of the interference waveform is generated; The second signal is projected onto the orthogonal subspace to obtain the interference suppression signal; The suppressed interference signal is demodulated to obtain the original symbol sequence, which is formed by the second signal suppressing the interference signal.

2. The communication anti-interference method based on waveform orthogonality according to claim 1, characterized in that, The method for obtaining the interference signal is as follows: Obtain the binary bit sequence generated by the interference end For the bit sequence Perform serial-to-parallel conversion, that is, convert the bit sequence The odd and even sequences are respectively subjected to 16-bit spread spectrum modulation to obtain the first spread spectrum signal. Second spread spectrum signal The first spread spectrum signal was respectively... Modulate and modulate the second spread spectrum signal Modulation is performed to obtain the first modulation signal. Where 1 is the real part of the first modulation signal. j This is the imaginary part of the first modulated signal; The first modulated signal is passed through a root-raised cosine filter, and insertion is performed within each symbol of the first modulated signal. NN At each point, the interference signal was obtained. ,in, i The value is the result of discretely sampling the interference signal. N The number of points after discrete sampling of the interference signal.

3. The communication anti-interference method based on waveform orthogonality according to claim 1, characterized in that, The detailed process of acquiring the modulated first signal from the transmitting end is as follows: Obtain the binary bit stream generated by the sending end For the bit stream Perform serial-to-parallel conversion, that is, convert the bit stream... The odd and even sequences are respectively subjected to 32-bit spread spectrum modulation to obtain the third spread spectrum signal. and the fourth spread spectrum signal The third and fourth spread spectrum signals are modulated respectively to obtain the second modulated signal. Where 1 is the real part of the second modulation signal. j This is the imaginary part of the second modulated signal; The second modulated signal is passed through a root-raised cosine filter, and four points are interpolated into each symbol of the second modulated signal to obtain the first signal. ,in, S The value is obtained by discretely sampling the first signal. M The number of points after discrete sampling of the first signal.

4. The communication anti-interference method based on waveform orthogonality according to claim 1, characterized in that, The first signal is superimposed with the interference signal and the noise signal to obtain the second signal. , y This refers to the value obtained after discretely sampling the second signal. N The number of points after the second signal is discretized; The first signal and the interference signal are at least partially superimposed, and the superimposed portion is located at least one of the beginning, middle or end portion of the first signal.

5. The communication anti-interference method based on waveform orthogonality according to claim 1, characterized in that, The detailed process of generating the orthogonal subspace of the interference waveform based on the interference waveform is as follows: Based on the interference waveform, obtain the autocorrelation matrix of the interference waveform. ;in, For interference waveforms The conjugate transpose of; Based on the interference waveform, the projected symbol vector is obtained. The first to the second symbol vector in the symbol vector NN The values ​​of each symbol vector are set to 0; The symbol vector Consolidate into columns of size 1 t First signal matrix , ,in, t The size of the projected feature vector; Unintegrated into the first signal matrix The symbol vector in Placed as the second signal matrix ; Based on the autocorrelation matrix of the interference waveform Generate the first signal matrix The autocorrelation matrix and the second signal matrix The autocorrelation matrix is ​​obtained, and eigenvalue decomposition is performed on each column of the signal in the autocorrelation matrix to obtain the orthogonal subspace of the interference waveform. Its expression is: ,in, As the dominant eigenvector matrix, It is a non-dominant eigenvector matrix. For the eigenvalue matrix, Dominant eigenvalue matrix : Non-dominant eigenvalue matrix The eigenvector matrix, It is the conjugate transpose of the eigenvector matrix.

6. The communication anti-interference method based on waveform orthogonality according to claim 5, characterized in that, for The vector, for A matrix of size, where, t The size of the projected feature vector.

7. The communication anti-interference method based on waveform orthogonality according to claim 5, characterized in that, The specific process of projecting the second signal onto the orthogonal subspace to obtain the interference suppression signal is as follows: Obtain the first signal matrix Each column of signals With the second signal matrix Projection matrix of the signal orthogonal subspace in ,in, It is the identity matrix; Based on the first signal matrix and the second signal matrix and the second signal superimposed by the interference symbols. Obtain the third signal matrix and the fourth signal matrix ,in, ; The third signal matrix and the fourth signal matrix The projection matrix projected onto the corresponding column Obtain multi-column recovery signal vectors ; The multiple recovered signal vectors are integrated into the interference suppression signal. .

8. A communication anti-interference device based on waveform orthogonality, applied to the communication anti-interference method based on waveform orthogonality as described in any one of claims 1-7, characterized in that, The device includes: The first acquisition module is used to acquire the first signal modulated by the transmitting end; The second acquisition module is used to acquire a second signal received by the receiving end; wherein the second signal is formed by superimposing an interference signal and a noise signal on the first signal, the interference signal being a signal existing in space, and the noise signal being a signal existing in the environment; The demodulation decision module is used to perform demodulation decision on the second signal and obtain the interference waveform in the second signal; including: demodulating the second signal... After low-pass filtering, the filtered signal is obtained. , N The number of points after discretizing the second signal is used to define the filtered signal. The processed signal is obtained by downsampling the symbol rate of the interference signal. A hard decision is made on the real part of the processed signal; when the real part of the processed signal... If the real part of the processed signal is 1, then the hard decision result is 1. If the hard decision result is -1, the first bipolar signal is obtained from the decision result of the real part of the processed signal; a hard decision is performed on the imaginary part of the processed signal, and when the imaginary part of the processed signal... If the imaginary part of the processed signal is true, the hard decision result is 1; If the hard decision result is -1, the second bipolar signal is obtained from the decision result of the imaginary part of the processed signal; then the first bipolar signal and the second bipolar signal are subjected to root raised cosine shaping to obtain the information sequence of the interference waveform in the second signal. ,in, The information sequence of the interference waveform is interpolated to obtain the interference waveform in the second signal. ;in, b For the information sequence of the interference waveform, 1+ j In the diagram, 1 represents the real part. j It is the imaginary part; The first generation module is used to generate an orthogonal subspace of the interference waveform based on the interference waveform; The second generation module is used to project the second signal onto the orthogonal subspace to obtain an interference suppression signal; The third generation module is used to demodulate the suppressed interference signal to obtain the original symbol sequence, which is formed by the second signal suppressing the interference signal.

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