An FDA physical layer signal electromagnetic distribution regulation method based on EWFRFT

Abstract

The application discloses an FDA physical layer signal electromagnetic distribution regulation method based on EWFRFT, and belongs to the technical field of physical layer security transmission of wireless communication.The application solves the problems of the insufficient physical layer signal waveform diversification characteristics and the poor anti-eavesdropping detection capability of the existing physical layer security technology.Through the design of a carrier frequency and a baseband weighting vector, the signal transmission system based on FDA realizes point-to-point security communication in combination with receiving and transmitting, so that the physical layer signal has the waveform diversification characteristics in three dimensions of distance, angle and time in the electromagnetic space.The EWFRFT processing realizes the effective promotion of the parameter dimension while being suitable for the basic properties of the communication system, enriches the waveform diversity characteristics, greatly enhances the difficulty of information interception of an eavesdropper and improves the anti-eavesdropping detection capability.The method can be applied to the technical field of physical layer security transmission of wireless communication.

Description

Technical Field

[0001] This invention belongs to the field of physical layer secure transmission technology in wireless communication, and specifically relates to a method for controlling the electromagnetic distribution of FDA physical layer signals based on EWFRFT. Background Technology

[0002] With the increasing demands of wireless services, physical layer security technologies have received widespread attention from researchers in academia and industry. Physical layer security methods based on artificial noise, spread spectrum communication, and frequency diversity arrays (FDAs) are emerging in large numbers. At the same time, various novel transform domain signal processing techniques are constantly developing. Among them, the Extended Weighted Fractional Fourier Transform (EWFRFT), compared to the classic weighted fractional Fourier transform, has eigenvalues ​​that are no longer limited by the transform order, thus offering greater flexibility and diversity in signal design.

[0003] However, with the continuous development of eavesdropping technology, the increasing sophistication of eavesdropping methods, and the continuous enhancement of the computing power of eavesdropping nodes, the existing physical layer security technologies still lack sufficient diversity in physical layer signal waveforms and have poor resistance to detection by eavesdropping terminals, which can easily lead to communication security risks. Summary of the Invention

[0004] The purpose of this invention is to address the problems of insufficient diversity of physical layer signal waveforms and poor resistance to eavesdropping detection in existing physical layer security technologies, and to propose an FDA physical layer signal electromagnetic distribution control method based on EWFRFT.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0006] A method for controlling the electromagnetic distribution of FDA physical layer signals based on EWFRFT, the method specifically includes the following steps:

[0007] Step 1: Perform baseband constellation mapping on the bit data (0, 1) to be transmitted to obtain the modulation result after constellation mapping. The modulation result is a serial signal.

[0008] Starting from the first bit of the modulation result, divide the modulation result into M data blocks of equal length, each data block having a length of 2. B B is a positive integer; the i-th data block is used as the data of the i-th frame. M is the total number of data blocks;

[0009] Where, x i,1 x i,2 and Represents the data X of the i-th frame. i The first, second, and second of them B A complex digital modulation symbol;

[0010] Step 2: Transfer the data of the i-th frame X i The output signal obtained after EWFRFT is represented as follows:

[0011] Where: s i,1 s i,2 and S represents i The first, second, and second of them B One signal data;

[0012] After performing EWFRFT on each frame of data obtained in step one, the output signal of each frame of data after EWFRFT is obtained;

[0013] Step 3: Using the FDA antenna transmission system, transmit the first signal data s from the output signal S1 obtained by EWFRFT of the first frame of data. 1,1 Transmit to the channel;

[0014] Step 4: The receiver receives the signal y(θ,r,t) from the channel;

[0015] Step 5: The receiver feeds the received signal y(θ,r,t) into N channels and performs down-conversion processing on the signals of each of the N channels. The down-conversion result of the m-th channel is represented as y′. m (θ,r,t);

[0016] Step 6: Perform low-pass filtering on the down-conversion results of each channel, and represent the low-pass filtered signal of the m-th channel as y″. m (θ,r,t);

[0017] Step 7: After low-pass filtering of all channels, the signal is passed through an analog-to-digital converter (ADC). The resulting signal data is summed and normalized to obtain the signal data y. 1,1 ;

[0018] Step 8: Repeat the signal transmission process from Step 3 to Step 7, and transmit each signal data in the output signal obtained by EWFRFT for each frame of data in sequence until all data blocks have been received.

[0019] Step 9: Starting from the first bit of the signal data obtained in Step 8 after processing at the receiving end, divide the signal data into M data blocks of equal length, each data block having a length of 2. B B is a positive integer;

[0020] The i-th data block is used as the i-th frame data signal.

[0021] Step 10: Perform IEBFRFT on each frame of data signal obtained in Step 9 to obtain the output signal of each frame of data signal after IEBFRFT. Then, convert the i-th frame of data signal Y... i The output signal after IEBFRFT is represented as Y_r i ;

[0022] Step 11: Represent all the output signals obtained in Step 10 as a single serial digital signal [Y_r1, Y_r2, ..., Y_r] M For [Y_r1,Y_r2,...,Y_r], M Perform constellation demapping to recover 0 and 1 bits of data.

[0023] The beneficial effects of this invention are:

[0024] This invention presents a system architecture design and implementation method for electromagnetic space waveform diversification of FDA physical layer signals based on EWFRFT. The FDA-based signal transmission system achieves point-to-point secure communication through carrier frequency and baseband weighted vector design, enabling the physical layer signal to exhibit waveform diversification characteristics in electromagnetic space across distance, angle, and time dimensions. EWFRFT processing, while adhering to the fundamental properties of communication systems, effectively enhances the parameter dimensions, enriches waveform diversity, significantly increases the difficulty for eavesdroppers to intercept information, and improves the ability to resist eavesdropper detection. The FDA physical layer signal based on EWFRFT has higher-dimensional transformation parameters, substantially improving the waveform diversity of the signal. While ensuring communication with cooperating parties, it degrades the reception performance of non-cooperative receivers. For multi-point collaborative reconnaissance, it can effectively suppress joint detection by reconnaissance nodes. The introduction of EWFRFT highlights the advantages of the electromagnetic space waveform diversification characteristics of the physical layer signal designed in this invention, further improving security performance in eavesdropping scenarios. Attached Figure Description

[0025] Figure 1 This is a flowchart of the transmitting end operation of the method of the present invention;

[0026] Figure 2 This is a flowchart of the receiving end process of the method of the present invention. Detailed Implementation

[0027] The present application will now be described in further detail with reference to specific embodiments and accompanying drawings. Obviously, the described embodiments are merely a part of the embodiments of the present invention, and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are all within the scope of protection of the present invention.

[0028] Specific Implementation Method 1: Combination Figure 1 and Figure 2 This embodiment describes a method for controlling the electromagnetic distribution of FDA physical layer signals based on EWFRFT. The method specifically includes the following steps:

[0029] Step 1: Perform baseband constellation mapping on the bit data (0, 1) to be transmitted to obtain the modulation result after constellation mapping. The modulation result is a serial signal.

[0030] This implementation method uses BPSK as an example, but it is compatible with other modulation methods.

[0031] Starting from the first bit of the modulation result, divide the modulation result into M data blocks of equal length, each data block having a length of 2. B B is a positive integer; the i-th data block is used as the data of the i-th frame. M is the total number of data blocks;

[0032] Where, x i,1 x i,2 and Represents the data X of the i-th frame. i The first, second, and second of them B A complex digital modulation symbol;

[0033] Step 2: Transfer the data of the i-th frame X i The output signal obtained after EWFRFT is represented as follows:

[0034] Where: s i,1 s i,2 and S represents i The first, second, and second of them B One signal data;

[0035] After performing EWFRFT on each frame of data obtained in step one, the output signal of each frame of data after EWFRFT is obtained;

[0036] Step 3: Using the FDA antenna transmission system, transmit the first signal data s from the output signal S1 obtained by EWFRFT of the first frame of data. 1,1 Transmit to the channel;

[0037] Step 4: The receiver receives the signal y(θ,r,t) from the channel;

[0038] Step 5: To achieve secure point-to-point communication with coordinated transmission and reception, the receiver feeds the received signal y(θ,r,t) into N channels and performs down-conversion processing on the signals of each of the N channels. The down-conversion result of the m-th channel is represented as y′. m (θ,r,t);

[0039] Step 6: Perform low-pass filtering on the down-conversion results of each channel, and represent the low-pass filtered signal of the m-th channel as y″. m (θ,r,t);

[0040] Step 7: After low-pass filtering of all channels, the signal is passed through an analog-to-digital converter (ADC). The resulting signal data is summed and normalized to obtain the signal data y. 1,1 ;

[0041] Step 8: Repeat the signal transmission process from Step 3 to Step 7, and transmit each signal data in the output signal obtained by EWFRFT for each frame of data in sequence until all data blocks have been received.

[0042] Step 9: Starting from the first bit of the signal data obtained in Step 8 after processing at the receiving end, divide the signal data into M data blocks of equal length, each data block having a length of 2. B B is a positive integer;

[0043] The i-th data block is used as the i-th frame data signal.

[0044] Step 10: Perform IEWFRFT (Inverse Extended Weighted Fractional Fourier Transform) on each frame of data signal obtained in Step 9 to obtain the output signal of each frame of data signal after IEWFRFT. Then, convert the i-th frame data signal Y... i The output signal after IEBFRFT is represented as Y_r i ;

[0045] Step 11: Represent all the output signals obtained in Step 10 as a single serial digital signal [Y_r1, Y_r2, ..., Y_r] M For [Y_r1,Y_r2,...,Y_r], M Perform constellation demapping to recover 0 and 1 bits of data.

[0046] This invention addresses the security vulnerabilities of existing systems by introducing FDA and EWFRFT. It achieves multi-dimensional control of the electromagnetic distribution of physical layer signals in both distance and angle dimensions, while simultaneously constructing physical layer waveforms with diverse waveform characteristics to assist in secure signal transmission. The EWFRFT-based electromagnetic distribution control system for FDA physical layer signals constructed in this invention further enhances the waveform diversity of transmitted signals, thereby significantly improving system security performance.

[0047] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the specific process of EWFRFT is as follows:

[0048] For the i-th frame data X i From the data of the i-th frame X i The first one to start with X i Perform intra-frame data grouping, dividing the data of the i-th frame X i Divided into 2 equal lengths B-1 Group, where the data in group k′ is represented as

[0049] For the first data in the group And the second data Perform EWFRFT:

[0050]

[0051]

[0052] Where X2 is The inverse vector, X2′ is The inverse vector of , w_F0 and w_F2 represent the weighting coefficients; F(·) represents EWFRFT;

[0053] Will and Perform summation and record the result as... The length is 2 1 ;

[0054] Similarly, after processing the data within each group, signal data is obtained. in, This indicates that for the data X in the i-th frame... i The signal obtained by processing the first set of data, This indicates that for the data X in the i-th frame... i The signal obtained by processing the second set of data This indicates that for the data X in the i-th frame... i The 2nd B-1 The signal obtained by processing a set of data;

[0055] Using the data X of the i-th frame i The grouping method divides the signal data Divided into 2 equal lengths B-2 The data is then grouped and EWFRFT is performed on the data within each group to obtain the signal data. in, Indicates the signal data The signal obtained by processing the first group of data after grouping. Indicates the signal data The signal obtained by processing the second group of data after grouping. Indicates the signal data The 2nd after grouping B-2 The signal obtained by processing a set of data;

[0056] And so on, until a length of 2 is obtained. B signal data Will This is represented as a single serial digital signal, which yields the data X of the i-th frame. i The output signal obtained by EWFRFT

[0057] The other steps and parameters are the same as in Specific Implementation Method 1.

[0058] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the weighting coefficients w_F0 and w_F2 are:

[0059]

[0060] Where θ0,θ1∈[0,2π) are transformation parameters, e is the base of the natural logarithm, and j is the imaginary unit.

[0061] Other steps and parameters are the same as in specific implementation method one or two.

[0062] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the specific process of step three is as follows:

[0063] In the FDA transmission system, N transmitting antennas are uniformly and linearly arranged to form a linear array antenna structure, and the spacing between adjacent transmitting antennas is d. The transmitting antenna farthest from the legal receiver is used as the reference element and is marked as element 0, i.e., n = 0. Then, in order of distance from the legal receiver from farthest to closest, the other transmitting antennas are numbered sequentially and marked as element n, n = 1, 2, ..., N-1.

[0064] The spacing d is:

[0065]

[0066] Where c represents the speed of light, f0 represents the carrier frequency of the signal emitted by the reference array element, Δf is the frequency increment, and Δf << f0;

[0067] Signal data s 1,1 Multiply by the baseband weighting coefficients, then perform digital-to-analog conversion on the result, and transmit the digital-to-analog conversion result to the channel through the transmit antenna. The transmitted signal of the nth array element is represented as e. n (t).

[0068] The other steps and parameters are the same as those in one of the specific implementation methods one to three.

[0069] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the transmitting signal e of the nth array element... n (t) is:

[0070]

[0071] Among them, w n f represents the baseband weighting coefficient of the nth element. n t represents the carrier frequency of the signal transmitted by array element n;

[0072] The carrier frequency f of the signal transmitted by the nth array element n for:

[0073] f n =f0+nΔf

[0074] The baseband weighting coefficient w n for:

[0075]

[0076] Where, θ D The azimuth angle r represents the direction of the normal to the linear array relative to the legitimate receiver. D This indicates the distance between the legitimate receiver and the reference array element.

[0077] The other steps and parameters are the same as those in one of the specific implementation methods one to four.

[0078] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the received signal y(θ,r,t) is:

[0079]

[0080] Where λ is the channel coefficient, R nLet g(t) be the distance between the receiver and the nth array element, and g(t) represent additive white Gaussian noise.

[0081] The transmitting antenna is isotropic and transmits the signal into the channel. When the receiver's position satisfies the far-field condition, the beam transmitted by the array can be considered a parallel beam. Therefore, the distance R between the receiver and the nth array element is... n =r-ndsinθ, n=0,...,N-1, θ represents the azimuth angle between the receiver and the normal direction of the linear array, and r represents the distance between the receiver and the reference array element;

[0082] Since (N-1)d << r and (N-1)Δf << f0, where "<<" represents much smaller than, therefore n 2 Δfdsinθ / c≈0, and remove the fixed phase bias. Then, the received signal y(θ,r,t) is simplified to:

[0083]

[0084] Where r represents the distance between the receiver and the reference array element, and θ represents the azimuth angle between the receiver and the normal direction of the linear array.

[0085] The other steps and parameters are the same as those in one of the specific implementation methods one to five.

[0086] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One through Six in that the down-conversion result y′ of the m-th channel... m (θ,r,t) is:

[0087]

[0088] Where m = 0, 1, ..., N-1, f m =f0+mΔf.

[0089] The other steps and parameters are the same as those in one of the specific implementation methods one to six.

[0090] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One through Seven in that the low-pass filtered signal y″ of the m-th channel... m (θ,r,t) is:

[0091]

[0092] in, Here, h(t) represents the convolution operator, h(t) represents the low-pass filter with a cutoff frequency of Δf / 2, and g′(t) represents the Gaussian white noise in the baseband.

[0093] The other steps and parameters are the same as those in any of the specific implementation methods one to seven.

[0094] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the signal data y 1,1 for:

[0095]

[0096] Where g″ represents the sampled Gaussian white noise.

[0097] The other steps and parameters are the same as those in one of the specific implementation methods one to eight.

[0098] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One to Nine in that the specific process of IEWFRFT is as follows:

[0099] For the data signal Y of the i-th frame i , for Y i Perform IEWFRFT as follows:

[0100]

[0101] Where X2″ is Y i The inverted vector, These are the inverse transform weighting coefficients, F -1 (·) represents IEBFRFT;

[0102]

[0103] make Will Divide the data into groups of length 2. B-1 bit 2 1 Group them and record the grouping results as follows: right Perform IEWFRFT separately to obtain the corresponding IEWFRFT results.

[0104] The obtained signal data Divided into two parts, each with a length of 2 B-2 bit 2 2 Group, and record the grouping results as Then perform IEWFRFT on each set of data to obtain the corresponding IEWFRFT results.

[0105] And so on, until we get 2. B The length of each group is 2 0 bit signal data The data signal Y in the i-th frame i The output signal obtained after IEWFRFT is

[0106] Similarly, the output signal obtained by passing each frame of data through IEWFRFT is obtained.

[0107] The other steps and parameters are the same as those in any of the specific implementation methods one to nine.

[0108] The above examples of the present invention are merely illustrative of the computational model and process of the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is impossible to exhaustively list all possible implementations here. Any obvious variations or modifications derived from the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for controlling the electromagnetic distribution of FDA physical layer signals based on EWFRFT, characterized in that, The method specifically includes the following steps: Step 1: Perform baseband constellation mapping on the bit data (0, 1) to be transmitted to obtain the modulation result after constellation mapping. The modulation result is a serial signal. Starting from the first bit of the modulation result, divide the modulation result into M data blocks of equal length, each data block having a length of 2. B B is a positive integer; the i-th data block is used as the data of the i-th frame. M is the total number of data blocks; Where, x i,1 x i,2 and Represents the data X of the i-th frame. i The first, second, and second of them B A complex digital modulation symbol; Step 2: Transfer the data of the i-th frame X i The output signal obtained after EWFRFT is represented as follows: Where: s i,1 s i,2 and S represents i The first, second, and second of them B One signal data; After performing EWFRFT on each frame of data obtained in step one, the output signal of each frame of data after EWFRFT is obtained; The specific process of EWFRFT is as follows: For the i-th frame data X i From the data of the i-th frame X i The first one to start with X i Perform intra-frame data grouping, dividing the data of the i-th frame X i Divided into 2 equal lengths B-1 Group, where the data in group k′ is represented as For the first data in the group And the second data Perform EWFRFT: Where X2 is The inverse vector, X2′ is The inverse vector of , w_F0 and w_F2 represent the weighting coefficients; F(·) represents EWFRFT; Will and Perform summation and record the result as... The length is 2 1 ; Similarly, after processing the data within each group, signal data is obtained. in, This indicates that for the data X in the i-th frame... i The signal obtained by processing the first set of data, This indicates that for the data X in the i-th frame... i The signal obtained by processing the second set of data This indicates that for the data X in the i-th frame... i The 2nd B-1 The signal obtained by processing a set of data; signal data Divided into 2 equal lengths B-2 The data is then grouped and EWFRFT is performed on the data within each group to obtain the signal data. in, Indicates the signal data The signal obtained by processing the first group of data after grouping. Indicates the signal data The signal obtained by processing the second group of data after grouping. Indicates the signal data The 2nd after grouping B-2 The signal obtained by processing a set of data; And so on, until a length of 2 is obtained. B signal data Will This is represented as a single serial digital signal, which yields the data X of the i-th frame. i The output signal obtained by EWFRFT Step 3: Using the FDA antenna transmission system, transmit the first signal data s from the output signal S1 obtained by EWFRFT of the first frame of data. 1,1 Transmit to the channel; The specific process of step three is as follows: In the FDA transmission system, N transmitting antennas are uniformly and linearly arranged to form a linear array antenna structure, and the spacing between adjacent transmitting antennas is d. The transmitting antenna farthest from the legal receiver is used as the reference element and is marked as element 0, i.e., n = 0. Then, in order of distance from the legal receiver from farthest to closest, the other transmitting antennas are numbered sequentially and marked as element n, n = 1, 2, ..., N-1. The spacing d is: Where c represents the speed of light, f0 represents the carrier frequency of the signal emitted by the reference array element, and Δf is the frequency increment; Signal data s 1,1 Multiply by the baseband weighting coefficients, then perform digital-to-analog conversion on the result, and transmit the digital-to-analog conversion result to the channel through the transmit antenna. The transmitted signal of the nth array element is represented as e. n (t); The transmission signal e of the nth array element n (t) is: Among them, w n f represents the baseband weighting coefficient of the nth element. n t represents the carrier frequency of the signal transmitted by array element n; The carrier frequency f of the signal transmitted by the nth array element n for: f n =f0+nΔf The baseband weighting coefficient w n for: Where, θ D The azimuth angle r represents the direction of the normal to the linear array relative to the legitimate receiver. D This indicates the distance between the legitimate receiver and the reference array element; Step 4: The receiver receives the signal y(θ,r,t) from the channel; The received signal y(θ,r,t) is: Where λ is the channel coefficient, R n Let g(t) be the distance between the receiver and the nth array element, and g(t) represent additive white Gaussian noise. Since (N-1)d << r and (N-1)Δf << f0, therefore n 2 Δfdsinθ / c≈0, and remove the fixed phase bias. Then, the received signal y(θ,r,t) is simplified to: Where r represents the distance between the receiver and the reference array element, and θ represents the azimuth angle between the receiver and the normal direction of the linear array; Step 5: The receiver feeds the received signal y(θ,r,t) into N channels and performs down-conversion processing on the signals of each of the N channels. The down-conversion result of the m-th channel is represented as y′. m (θ,r,t); The downconversion result y′ of the m-th channel m (θ,r,t) is: Where m = 0, 1, ..., N-1, f m =f0+mΔf; Step 6: Perform low-pass filtering on the down-conversion results of each channel, and represent the low-pass filtered signal of the m-th channel as y′. m ′(θ,r,t); The low-pass filtered signal y′ of the m-th channel m ′(θ,r,t) is: in, Here, h(t) represents a low-pass filter with a cutoff frequency of Δf / 2, and g′(t) represents Gaussian white noise in the baseband. Step 7: After low-pass filtering of all channels, the signal is passed through an analog-to-digital converter (ADC). The resulting signal data is summed and normalized to obtain the signal data y. 1,1 ; The signal data y 1,1 for: Where g″ represents the sampled Gaussian white noise; Step 8: Repeat the signal transmission process from Step 3 to Step 7, and transmit each signal data in the output signal obtained by EWFRFT for each frame of data in sequence until all data blocks have been received. Step 9: Starting from the first bit of the signal data obtained in Step 8 after processing at the receiving end, divide the signal data into M data blocks of equal length, each data block having a length of 2. B B is a positive integer; The i-th data block is used as the i-th frame data signal. Step 10: Perform IEBFRFT on each frame of data signal obtained in Step 9 to obtain the output signal of each frame of data signal after IEBFRFT. Then, convert the i-th frame of data signal Y... i The output signal after IEBFRFT is represented as Y_r i ; Step 11: Represent all the output signals obtained in Step 10 as a single serial digital signal [Y_r1, Y_r2, ..., Y_r] M For [Y_r1,Y_r2,...,Y_r], M Perform constellation demapping to recover 0 and 1 bits of data.

2. The method for controlling the electromagnetic distribution of FDA physical layer signals based on EWFRFT according to claim 1, characterized in that, The weighting coefficients w_F0 and w_F2 are: Where θ0,θ1∈[0,2π) are transformation parameters, e is the base of the natural logarithm, and j is the imaginary unit.

3. The method for controlling the electromagnetic distribution of FDA physical layer signals based on EWFRFT according to claim 2, characterized in that, The specific process of IEWFRFT is as follows: For the data signal Y of the i-th frame i , for Y i Perform IEWFRFT as follows: Where X2″ is Y i The inverted vector, These are the inverse transform weighting coefficients, F -1 (·) represents IEBFRFT; make Will Divide the data into groups of length 2. B-1 bit 2 1 Group them and record the grouping results as follows: right Perform IEWFRFT separately to obtain the corresponding IEWFRFT results. The obtained signal data Divided into two parts, each with a length of 2 B-2 bit 2 2 Group, and record the grouping results as Then perform IEWFRFT on each set of data to obtain the corresponding IEWFRFT results. And so on, until we get 2. B The length of each group is 2 0 bit signal data The data signal Y in the i-th frame i The output signal obtained after IEWFRFT is Similarly, the output signal obtained by passing each frame of data through IEWFRFT is obtained.

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