A method and system for designing a MIMO radar communication integrated waveform using spectral amplitude implant information

Abstract

The application discloses a MIMO radar communication integrated waveform design method and system using spectrum amplitude to implant information, and belongs to the technical field of radar systems and radar signal processing. The method comprises the following steps: a detection waveform optimization model is established based on a power matching criterion according to prior knowledge of a radar target distribution space; expected spectrum amplitudes of a MIMO array transmitting waveform in a communication receiver direction synthesis signal are determined according to a communication information implanting rule, and a communication waveform optimization model based on an error energy constraint is established on the basis; a MIMO radar communication integrated waveform relaxation optimization model is established by combining the above two models; a double-function integrated waveform optimization model under a constant modulus constraint is solved based on a cyclic algorithm and an MM algorithm; and the communication receiver decodes the synthesis signal based on a spectrum amplitude segmented summation criterion, and completes communication information transmission with a multi-function electronic information system.

Description

Technical Field

[0001] This invention belongs to the field of radar systems and radar signal processing technology, and particularly relates to a MIMO radar communication integrated waveform design method and system that utilizes spectrum amplitude to embed information. Background Technology

[0002] With the continuous development of information technology, the performance of modern electronic information equipment has improved dramatically, and the demands of various users are constantly increasing. This has led to a sharp increase in the number of electronic information devices in limited spaces, making the electromagnetic environment extremely complex. The most prominent problem is the overlap of operating frequency bands between radar, communication, and jamming devices, resulting in increasingly serious unintentional interference. Solving the spectrum compatibility problem between electronic devices for different purposes has become an urgent task.

[0003] Traditional methods such as frequency segmentation, spatial segmentation, and time segmentation inevitably limit the performance of radar, communication, and other equipment to varying degrees. Therefore, researching a dual-function electronic information system that utilizes the same platform, equipment, and spectrum resources to simultaneously perform target detection and communication information transmission is of great significance. This is not only an important measure to solve electromagnetic spectrum congestion between different devices but also a powerful support for enhancing the comprehensive capabilities of electronic information systems.

[0004] The prerequisite for achieving dual radar and communication functions is the design of a high-performance integrated detection waveform. Current mainstream design methods include amplitude control, phase control, sparse array element selection, combined amplitude and phase optimization, and direct matching of synthesized signals. These methods improve the performance of the integrated waveform to varying degrees, but they still have certain shortcomings in terms of bit error rate during communication transmission due to their weak ability to suppress receiver thermal noise. Summary of the Invention

[0005] To address the aforementioned issues, this invention utilizes a MIMO array as a platform and, in the radar aspect, takes desired pattern matching as the criterion, proposes an integrated radar-communication waveform design method and system that incorporates spectral amplitude information. This invention further reduces the bit error rate of communication information transmission without significantly weakening radar detection performance, effectively improving the transmission performance of communication information.

[0006] The first aspect of this invention proposes a waveform design method for integrated MIMO radar communication that utilizes spectral amplitude-embedded information, the method comprising:

[0007] Step S1: Based on prior knowledge of the radar target distribution airspace, establish a detection waveform optimization model based on the power matching criterion;

[0008] Step S2: Based on the communication information implantation rules, determine the expected spectral amplitude of the synthesized signal of the MIMO array transmit waveform in the direction of the communication receiver;

[0009] Step S3: Based on the expected spectral amplitude of the synthesized signal in the direction of the communication receiver, establish a communication waveform optimization model based on error energy constraints;

[0010] Step S4: Establish an integrated waveform relaxation optimization model for MIMO radar communication;

[0011] Step S5: Solve the dual-function integrated waveform optimization model under constant modulus constraints based on the cyclic algorithm and the MM algorithm;

[0012] Step S6: The communication receiver decodes the synthesized signal based on the spectrum amplitude segment summation criterion, and completes the communication information transmission with the multifunctional electronic information system.

[0013] In step S1:

[0014] The transmit waveform matrix of the MIMO array is Among them, s n =[s1(n),s2(n),…,s M (n)] T This represents the transmitted waveform of the nth (n = 1, 2, ..., N) sub-pulse, where M is the number of transmitting array elements and N is the number of sub-pulses.

[0015] The synthesized signal power of the MIMO array at far-field space θ is P(θ)=||a H (θ)S|| 2 ;in,(·) T The · symbol represents the transpose of a matrix or vector. H ||·|| represents the conjugate transpose of a matrix or vector. 2 Let a(θ) represent the sum of squares of all elements of the vector, where a(θ) = [1, e^(-θ). jπsinθ ,…,e jπ(M-1)sinθ ] T This represents the emission steering vector in the θ direction;

[0016] Based on the spatial composite power of the transmitted waveform and the desired transmitted pattern, an optimization model for the MIMO array detection waveform is established:

[0017]

[0018] st|S(m,n)|=1,m=1,2,...,M,n=1,2,...,N

[0019] in, Represents θ k The launch steering vector in the direction, θ k Let w represent the k-th discretized angle in space, and let K be the total number of discretized angles in the entire space. k For θk Weighting coefficients for directional transmit power matching error. Let S be the desired radar pattern of the MIMO array, α be the scale factor used to compensate for the mismatch between the desired and actual patterns, S(m,n) be the element in the m-th row and n-th column of matrix S, and |·| be the modulus value.

[0020] In step S2:

[0021] One bit of information is transmitted using the amplitude spectrum at N1 frequency points, and the spectrum of the entire synthesized signal is divided into N / N1 parts;

[0022] The desired spectral amplitude is divided into three levels. The spectral amplitude value for the first N / N1 reference frequency points is σ1 = 5. For the spectral amplitude of subsequent frequency points, if the transmission is 0, the spectral amplitude value for the corresponding N / N1 frequency points is σ2 = 10. -6 If transmission 1 is performed, the spectral amplitude value of the corresponding N / N1 frequency points is σ3 = 10.

[0023] The expected spectral amplitude of the synthesized signal in the direction of the communication receiver by the MIMO array during the radar pulse is:

[0024] In step S3:

[0025] The space-based self-communication receiver is located in the far-field direction θ of the MIMO array. c At the location, the synthesized signal at the communication receiver is Among them, a c The corresponding directional guide vector;

[0026] The spectrum is obtained by performing a Fourier transform on the synthesized signal. in, p represents a multiple of the fundamental frequency;

[0027] Based on the synthesized signal spectrum, a communication waveform optimization model for the MIMO array is established:

[0028]

[0029] |S(m,n)|=1,m=1,2,…,M,n=1,2,…,N

[0030] Where γ > 0 is a scaling factor used to mitigate the matching error between the synthesized signal's spectral amplitude and the desired spectral amplitude; η p It represents the weighting coefficient of the matching error at the p-th frequency point of the received signal spectrum amplitude by the communication equipment.

[0031] In step S4:

[0032] By combining the MIMO array detection waveform optimization model and the communication waveform optimization model, an integrated waveform optimization model with both detection and communication functions is obtained:

[0033]

[0034] st|S(m,n)|=1,m=1,2,...,M,n=1,2,...,N

[0035] Where 0≤β≤1 is a scaling factor, used to balance radar detection performance and communication information transmission performance. When β=0, only communication performance is considered, and when β=1, only radar performance is considered.

[0036] The transmitted waveform matrix is ​​vectorized, and the non-convex constraint of the synthesized signal spectrum amplitude matching is transformed into a complex fitting error constraint, thus establishing a relaxed integrated waveform optimization model:

[0037]

[0038] st|s(l)|=1,l=1,2,…,MN

[0039] Where s = vec T (S), vec(·) indicates that the matrix is ​​straightened by columns; I N It is an N-dimensional identity matrix. This represents the kron product, and (·)* represents the conjugate of a matrix or vector; The phase factor is an auxiliary variable introduced to simplify the problem-solving process.

[0040] In step S5, the integrated waveform optimization model is a multivariable nonconvex optimization problem, which is solved using a cyclic algorithm, specifically including:

[0041] Steps S5-1, s, γ and Update α at a certain time:

[0042]

[0043] When steps S5-2, s, γ, and α are constant, update

[0044]

[0045] Where angle(·) represents taking the phase;

[0046] Step S5-3, s, With α constant, update γ:

[0047]

[0048] Step S5-4, γ, With α constant, update s:

[0049] Construct an upper bound function and relax it into a quadratic optimization problem in terms of s:

[0050]

[0051] st|s(l)|=1,l=1,2,…,MN

[0052] in, s q Let be the iteration value of s at step q. c1 is a fixed constant, and Re(·) represents taking the real part;

[0053] The quadratic optimization problem can be relaxed into a linear optimization problem under equality constraints using the MM algorithm:

[0054]

[0055] st|s(l)|=1,l=1,2,…,MN

[0056] Where, u=(L B ′-B′+MNκ)(s q ) H L B′ =diag(|B′|e), where diag(·) denotes vector matrixing, and e is a vector of all 1s of the corresponding dimension; v = λ max (s q ) H -P(s q H+γq,

[0057] γ、 When α is constant, the optimal value of s is

[0058] Let q = q + 1, and repeat the calculation. Until the change value of the original objective function of the integrated waveform meets the preset threshold;

[0059] Step S5-5: Iterate through steps S5-1 to S5-4, alternately solving for γ. α and s; until the change value of the original objective function meets the preset threshold, stop the iteration, and obtain the optimal transmission waveform for MIMO radar-communication integration.

[0060] In step S6,

[0061] The spectrum of the synthesized signal intercepted by the communication receiver is Where, n p The spectrum of Gaussian white noise inside the receiver;

[0062] Record the start time of the MIMO array's transmitted signal, and use the known spatial relationship between the MIMO platform and the communication receiver to calculate the signal start time of the communication receiver;

[0063] The complete received communication signal is extracted according to the known pulse code length, and then subjected to Fourier transform. The number of normalized frequency points is N, thereby obtaining the spectral amplitude.

[0064] According to the known coding rules, the spectral amplitude is divided into N / N1 parts, with each segment consisting of N1 points;

[0065] Compare the absolute sum of the amplitudes of the following N / N1-1 spectral segments with the absolute sum of the amplitudes of the first spectral segment; if the sum is greater than the absolute sum of the amplitudes of the first spectral segment, decode as 1; otherwise decode as 0.

[0066] A second aspect of this invention discloses an integrated waveform design system for MIMO radar communication utilizing spectral amplitude implantation information. The system includes a processing unit configured to perform the following steps:

[0067] Step S1: Based on prior knowledge of the radar target distribution airspace, establish a detection waveform optimization model based on the power matching criterion;

[0068] Step S2: Based on the communication information implantation rules, determine the expected spectral amplitude of the synthesized signal of the MIMO array transmit waveform in the direction of the communication receiver;

[0069] Step S3: Based on the expected spectral amplitude of the synthesized signal in the direction of the communication receiver, establish a communication waveform optimization model based on error energy constraints;

[0070] Step S4: Establish an integrated waveform relaxation optimization model for MIMO radar communication;

[0071] Step S5: Solve the dual-function integrated waveform optimization model under constant modulus constraints based on the cyclic algorithm and the MM algorithm;

[0072] Step S6: The communication receiver decodes the synthesized signal based on the spectrum amplitude segment summation criterion, and completes the communication information transmission with the multifunctional electronic information system.

[0073] A third aspect of this invention discloses an electronic device. The electronic device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps of the MIMO radar communication integrated waveform design method using spectral amplitude-embedded information as described in the first aspect of this disclosure.

[0074] A fourth aspect of this invention discloses a computer-readable storage medium. The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the MIMO radar communication integrated waveform design method using spectral amplitude-embedded information as described in the first aspect of this disclosure.

[0075] In summary, the beneficial effects of the present invention are as follows:

[0076] 1. This invention is based on a radar-communication integrated waveform designed with a MIMO array, which enables the MIMO array to focus the transmit power within a specified desired airspace and synthesize the required communication signal in the direction of the communication receiver to achieve communication information transmission. In complex electromagnetic environments, it can simultaneously ensure the target detection capability and covert communication capability of our electronic information system.

[0077] 2. Compared with existing integrated waveform design methods, this invention makes full use of the characteristics of Gaussian white noise and signal independent distribution. Based on the uniformity of the noise power spectrum and its weak influence on the shape of the signal spectrum amplitude, it proposes a strategy of embedding communication information using spectrum amplitude, which can reduce the bit error rate of communication information transmission by about one order of magnitude.

[0078] 3. The encoding method of this invention is very flexible. It can reasonably adjust variables such as the total length of a single pulse code and the number of encoded bits according to actual application needs, so as to achieve a trade-off between communication information transmission rate and bit error rate.

[0079] 4. The pattern matching model, communication information implantation strategy, and optimization problem-solving method proposed in this invention can provide a reference for the optimized design of multi-functional integrated waveforms for detecting communication interference. Attached Figure Description

[0080] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0081] Figure 1 This is a flowchart illustrating the transmission waveform design used in this invention;

[0082] Figure 2 This is a schematic diagram of synthesized signal decoding based on the spectral amplitude segmentation summation criterion;

[0083] Figure 3 To synthesize a radar transmission pattern using the waveform optimized by this invention;

[0084] Figure 4 To synthesize the spectrum amplitude diagram of the communication signal using the waveform optimized by this invention;

[0085] Figure 5 This diagram illustrates the variation of the bit error rate of communication information transmission with the signal-to-noise ratio obtained using the encoding / decoding strategy proposed in this invention. Detailed Implementation

[0086] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0087] Based on the traditional MIMO radar transmit waveform design, this invention further considers the dual functions of target detection and communication information transmission, and proposes a radar-communication integrated waveform design method and system that utilizes spectrum amplitude to embed information. By rationally designing the transmit waveform, the MIMO array can achieve transmit power focusing in the specified desired airspace while synthesizing the required communication signal in the direction of the communication receiver. Through information decoding, effective information transmission with friendly communication equipment can be completed, which greatly improves the target detection capability and covert communication capability of our electronic information system.

[0088] This invention first establishes a detection waveform optimization model based on prior knowledge of the radar target distribution airspace and a power matching criterion. Second, based on communication information implantation rules, it determines the expected spectral amplitude of the synthesized signal in the direction of the communication receiver from the MIMO array's transmitted waveform, and establishes a communication waveform optimization model based on error energy constraints. Third, combining the above two models and for ease of subsequent solution, a MIMO radar-communication integrated waveform relaxation optimization model is established. Fourth, the dual-function integrated waveform optimization model under constant modulus constraints is solved using a cyclic algorithm and a Majorization-Minimization (MM) algorithm. Finally, the communication receiver decodes the synthesized signal based on the spectral amplitude segmented summation criterion, completing the communication information transmission with the multifunctional electronic information system. This method enables the MIMO array to achieve transmit power focusing in a specified desired airspace while synthesizing the required communication signal in the direction of the communication receiver. Effective information transmission with friendly communication equipment can be completed through information decoding. Furthermore, it exhibits strong robustness to Gaussian white noise, greatly enhancing the target detection and covert communication capabilities of our electronic information system.

[0089] The first aspect of this invention proposes a waveform design method for integrated MIMO radar communication that utilizes spectral amplitude-embedded information, the method comprising:

[0090] 1. Based on prior knowledge of the radar target distribution airspace, an optimization model for the detection waveform is established based on the power matching criterion.

[0091] (1) Let the transmit waveform matrix of the MIMO array be... Where s n =[s1(n),s2(n),…,s M (n)] T Let M represent the transmitted waveform of the nth (n = 1, 2, ..., N) sub-pulse, M be the number of transmitting array elements, and N be the number of sub-pulses. The synthesized signal power of the MIMO array at far-field space θ is given as:

[0092] P(θ=||a H (θ)S|| 2

[0093] in,(·) T The · symbol represents the transpose of a matrix or vector. H ||·|| represents the conjugate transpose of a matrix or vector. 2 Let a(θ) represent the sum of squares of all elements of the vector, where a(θ) = [1, e^(-θ). jπsinθ ,…,e jπ(M-1)sinθ ] T This represents the launch steering vector in the θ direction.

[0094] (2) Based on the spatial composite power of the transmitted waveform and the desired transmitted pattern, the MIMO array detection waveform optimization model is established as follows:

[0095]

[0096] st|S(m,n)|=1,m=1,2,…,M,n=1,2,…,N

[0097] in, Represents θ k The launch steering vector in the direction, θ k Let w represent the k-th discretized angle in space, and let K be the total number of discretized angles in the entire space. k For θ k Weighting coefficients for directional transmit power matching error. Let S be the desired radar pattern of the MIMO array, α be the scale factor used to compensate for the mismatch between the desired and actual patterns, S(m,n) be the element in the m-th row and n-th column of matrix S, and |·| be the modulus value.

[0098] 2. Based on the communication information implantation rules, determine the desired spectral amplitude of the synthesized signal from the MIMO array's transmitted waveform in the direction of the communication receiver. Let the amplitude spectrum of N1 frequency points transmit one bit of information. The spectrum of the entire synthesized signal can be divided into N / N1 (generally integer) parts. Divide the desired spectral amplitude into three levels: the spectral amplitude value of the first N / N1 reference frequency points is σ1 = 5; for the spectral amplitude of subsequent frequency points, if "0" is to be transmitted, let the spectral amplitude value of the corresponding N / N1 frequency points be σ2 = 10. -6 If a "1" is to be transmitted, then the spectral amplitude of the corresponding N / N1 frequency points is set to σ3 = 10. Based on this rule, the expected spectral amplitude of the synthesized signal of the MIMO array in the direction of the communication receiver during a certain radar pulse is denoted as...

[0099] 3. Based on the expected spectral amplitude of the synthesized signal in the direction of the communication receiver, establish a communication waveform optimization model based on error energy constraints.

[0100] (1) Assume that the space-based friendly communication receiver is located in the far-field direction θ of the MIMO array. c At that point, the synthesized signal at the communication receiver is Among them, a c This represents the steering vector in the corresponding direction. The Fourier transform of the synthesized signal yields its spectrum:

[0101]

[0102] in, p represents a multiple of the fundamental frequency.

[0103] (2) Based on the spectrum of the synthesized signal, the communication waveform optimization model of the MIMO array is established as follows:

[0104]

[0105] |S(m,n)|=1,m=1,2,…,M,n=1,2,…,N

[0106] Where γ > 0 is a scaling factor, used to compensate for the matching error between the synthesized signal's spectral amplitude and the desired spectral amplitude; η p This represents the weighting coefficient for the matching error at the p-th frequency point of the received signal spectrum amplitude by the communication device, and its effect is related to w. k similar.

[0107] 4. To facilitate subsequent solutions, a waveform relaxation optimization model integrating MIMO radar and communication is established.

[0108] (1) By combining the MIMO array detection waveform optimization model and the communication waveform optimization model, an integrated waveform optimization model with both detection and communication functions can be given as follows:

[0109]

[0110] st|S(m,n)|=1,m=1,2,…,M,n=1,2,…,N

[0111] Here, 0≤β≤1 is a scaling factor used to balance radar detection performance and communication information transmission performance. When β=0, only communication performance is considered, and when β=1, only radar performance is considered.

[0112] (2) To facilitate subsequent derivation and solution, the transmitted waveform matrix needs to be vectorized, and the non-convex constraint of synthesized signal spectrum amplitude matching needs to be transformed into a complex fitting error constraint. Based on this, a relaxed integrated waveform optimization model can be established:

[0113]

[0114] st|s(l)|=1,l=1,2,…,MN

[0115] Where s = vec T (S), vec(·) indicates that the matrix is ​​straightened by columns; I N It is an N-dimensional identity matrix. This represents the kron product, (·). * Represents the conjugate of a matrix or vector; The phase factor is an auxiliary variable introduced to simplify the problem-solving process.

[0116] 5. Solve the dual-function integrated waveform optimization model under constant modulus constraints based on the cyclic algorithm and the MM algorithm.

[0117] The integrated waveform optimization model is a multivariable non-convex optimization problem. This problem can be solved using a cyclic algorithm, which consists of five parts, detailed below:

[0118] (1) s, γ and Update α at a certain time:

[0119]

[0120] (2) When s, γ, and α are constant, update

[0121]

[0122] Here, angle(·) represents taking the phase.

[0123] (3)s、 With α constant, update γ:

[0124]

[0125] (4)γ、 With α constant, update s:

[0126] Since the original problem is a fourth-order optimization problem in terms of s, it is difficult to solve directly. This invention constructs a suitable upper bound function to relax it into a quadratic optimization problem in terms of s, as shown in the model below:

[0127]

[0128] st|s(l)|=1,l=1,2,…,MN

[0129] in, s q Let be the iteration value of s at step q. c1 is a fixed constant, and Re(·) represents taking the real part. However, the above model still belongs to a non-convex optimization problem. Therefore, this invention patent again uses the MM algorithm to relax it into a linear optimization problem under equality constraints:

[0130]

[0131] st|s(l)|=1,l=1,2,…,MN

[0132] In the above equation, fixed constants that are irrelevant to the optimization are ignored, u=(L B′ -B′+MNκ)(s q ) H L B′ -diag(|B′|e), where diag(·) denotes vector matrixing, and e is a vector of all 1s of the corresponding dimension; v = λ max (s q ) H -P(s q ) H +γq, γ can be easily obtained from the above formula. When α is constant, the optimal value of s is Let q = q + 1, and repeat the calculation. The process continues until the change value of the original objective function of the integrated waveform meets the preset threshold.

[0133] (5) Iterate through (1) to (4) alternately to solve γ, The iteration stops when the change value of the original objective function meets the preset threshold, thus obtaining the optimal transmission waveform for MIMO radar-communication integration.

[0134] 6. The communication receiver decodes the synthesized signal based on the spectral amplitude segmentation and summation criterion, completing the communication information transmission with the multifunctional electronic information system. Assume the spectrum of the synthesized signal intercepted by the communication receiver is: Where, n p This describes the spectrum of Gaussian white noise inside the receiver. First, the start time of the MIMO array's transmitted signal is recorded, and the signal start time of the communication receiver is calculated using the known spatial relationship between the MIMO platform and the communication receiver. Second, the complete received communication signal is extracted according to the known pulse code length, and its spectral amplitude is obtained by performing a Fourier transform (normalized frequency points are N). Third, according to the known coding rules, the spectral amplitude is divided into N / N1 parts, with each segment consisting of N1 points. Finally, the absolute sum of the spectral amplitudes of the remaining N / N1-1 parts is compared with the absolute sum of the spectral amplitudes of the first part. If it is greater than the absolute sum of the spectral amplitudes of the first part, it is decoded as "1"; otherwise, it is decoded as "0". Figure 2 As shown.

[0135] Simulation Example

[0136] Simulation conditions: The number of elements in the MIMO array is M=10, the encoding length of the transmitted waveform of each element is N=128, the desired spatial domain is specified as [-20°, 20°], the entire spatial domain is discretized into 181 grid points, the discretization interval is 1°, and the relative direction between the spatial receiver and the MIMO array is set to -45°. (The last part, "w", appears to be an unrelated instruction and is left untranslated.) k =1, k=1,2,…,K,η p =1, p=0,1,…,N-1, β=10 -3 When N1 = 16, the change in the objective function value between adjacent iterations is less than 10. -4 When the iteration stops, the initial waveform is generated using a random method.

[0137] Figure 3 The radar transmission pattern synthesized from the optimized waveform obtained in this invention is shown, as follows: Figure 3 As shown, the optimized transmission pattern achieves power focusing in the specified desired airspace, which effectively improves power utilization compared to traditional orthogonal MIMO radar, provides a higher signal-to-noise ratio for echo signal processing, and is more useful for target detection and parameter estimation.

[0138] Figure 4 The spectral amplitude of the synthesized signal in the direction of the communication receiver for the waveform optimized by this invention is given, such as... Figure 4As shown, both the amplitude of the synthesized signal spectrum and the amplitude of the actual received signal spectrum (signal-to-noise ratio of 5dB) are effectively fitted to the expected amplitude, which lays a favorable foundation for subsequent interpretation of communication signal information.

[0139] Figure 5 The paper presents the variation of the bit error rate (BER) of the communication information transmission obtained after decoding the optimized waveform of this invention at the communication receiver as a function of the signal-to-noise ratio (SNR) (-20dB to 20dB, 21 discrete points, 40,000 equivalent Monte Carlo experiments). Figure 5 As shown, with the increase of signal-to-noise ratio, the bit error rate of communication information transmission decreases rapidly. When the signal-to-noise ratio is greater than 4dB, the bit error rate is already below 1%, approximately 0.4%. When the signal-to-noise ratio is greater than 10dB, the bit error rate can be basically controlled to below 0.01%. This indicates that the communication information implantation method proposed in this invention has stronger robustness against noise.

[0140] comprehensive Figures 3-5 As can be seen, the MIMO radar communication integrated waveform design method and system proposed in this invention, which utilizes spectrum amplitude to embed information, enables the MIMO array to focus its transmission power in a specified desired airspace, synthesizes the required communication signal in the direction of the communication receiver, and achieves effective information transmission with friendly communication equipment through information decoding, which greatly enhances the target detection capability and covert communication capability of our electronic information system.

[0141] A second aspect of this invention discloses an integrated waveform design system for MIMO radar communication utilizing spectral amplitude implantation information. The system includes a processing unit configured to perform the following steps:

[0142] Step S1: Based on prior knowledge of the radar target distribution airspace, establish a detection waveform optimization model based on the power matching criterion;

[0143] Step S2: Based on the communication information implantation rules, determine the expected spectral amplitude of the synthesized signal of the MIMO array transmit waveform in the direction of the communication receiver;

[0144] Step S3: Based on the expected spectral amplitude of the synthesized signal in the direction of the communication receiver, establish a communication waveform optimization model based on error energy constraints;

[0145] Step S4: Establish an integrated waveform relaxation optimization model for MIMO radar communication;

[0146] Step S5: Solve the dual-function integrated waveform optimization model under constant modulus constraints based on the cyclic algorithm and the MM algorithm;

[0147] Step S6: The communication receiver decodes the synthesized signal based on the spectrum amplitude segment summation criterion, and completes the communication information transmission with the multifunctional electronic information system.

[0148] A third aspect of this invention discloses an electronic device. The electronic device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps of the MIMO radar communication integrated waveform design method using spectral amplitude-embedded information as described in the first aspect of this disclosure.

[0149] A fourth aspect of this invention discloses a computer-readable storage medium. The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the MIMO radar communication integrated waveform design method using spectral amplitude-embedded information as described in the first aspect of this disclosure.

[0150] In summary, the beneficial effects of the present invention are as follows:

[0151] 1. This invention is based on a radar-communication integrated waveform designed with a MIMO array, which enables the MIMO array to focus the transmit power within a specified desired airspace and synthesize the required communication signal in the direction of the communication receiver to achieve communication information transmission. In complex electromagnetic environments, it can simultaneously ensure the target detection capability and covert communication capability of our electronic information system.

[0152] 2. Compared with existing integrated waveform design methods, this invention makes full use of the characteristics of Gaussian white noise and signal independent distribution. Based on the uniformity of the noise power spectrum and its weak influence on the shape of the signal spectrum amplitude, it proposes a strategy of embedding communication information using spectrum amplitude, which can reduce the bit error rate of communication information transmission by about one order of magnitude.

[0153] 3. The encoding method of this invention is very flexible. It can reasonably adjust variables such as the total length of a single pulse code and the number of encoded bits according to actual application needs, so as to achieve a trade-off between communication information transmission rate and bit error rate.

[0154] 4. The pattern matching model, communication information implantation strategy, and optimization problem-solving method proposed in this invention can provide a reference for the optimized design of multi-functional integrated waveforms for detecting communication interference.

[0155] Please note that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A waveform design method for MIMO radar communication integrating spectral amplitude implantation information, characterized in that, The method includes: Step S1: Based on prior knowledge of the radar target distribution airspace, establish a detection waveform optimization model based on the power matching criterion; In step S1: The transmit waveform matrix of the MIMO array is ;in, Indicates the first The transmitted waveform of each sub-pulse , The number of transmitting array elements, The number of sub-pulses; MIMO arrays in far-field space The synthesized signal power at the location is ;in, Represents the transpose of a matrix or vector. Represents the conjugate transpose of a matrix or vector. This represents the sum of squares of all elements of the vector. express The launch steering vector in the direction; Step S2: Based on the communication information implantation rules, determine the expected spectral amplitude of the synthesized signal of the MIMO array transmit waveform in the direction of the communication receiver; In step S2: by The amplitude spectrum at each frequency point transmits one bit of information, and the spectrum of the entire synthesized signal is divided into... Each part; The desired spectral amplitude is divided into three levels, the first... The spectral amplitude value of each reference frequency point is For the spectral amplitude of subsequent frequency points, if the transmission is 0, then the corresponding... The spectral amplitude value of each frequency point If 1 is transmitted, then the corresponding The spectral amplitude value of each frequency point ; The expected spectral amplitude of the synthesized signal in the direction of the communication receiver by the MIMO array during the radar pulse is: ; Step S3: Based on the expected spectral amplitude of the synthesized signal in the direction of the communication receiver, establish a communication waveform optimization model based on error energy constraints; In step S3: The space-based self-communication receiver is located in the far field direction of the MIMO array. At the location, the synthesized signal at the communication receiver is ,in, The corresponding directional guide vector; The spectrum is obtained by performing a Fourier transform on the synthesized signal. ;in, , Indicates a multiple of the fundamental frequency; Based on the synthesized signal spectrum, a communication waveform optimization model for the MIMO array is established: in, This is a scaling factor used to mitigate the matching error between the synthesized signal's spectral amplitude and the desired spectral amplitude. Indicates the amplitude of the received signal spectrum of the communication device. Weighting coefficients for matching errors at each frequency point; Step S4: Establish an integrated waveform relaxation optimization model for MIMO radar communication; Step S5: Solve the dual-function integrated waveform optimization model under constant modulus constraints based on the cyclic algorithm and the MM algorithm; Step S6: The communication receiver decodes the synthesized signal based on the spectrum amplitude segment summation criterion to complete the communication information transmission with the multifunctional electronic information system; In step S6, The spectrum of the synthesized signal intercepted by the communication receiver is ;in, The spectrum of Gaussian white noise inside the receiver. , as an auxiliary variable For phase factor; Record the start time of the MIMO array's transmitted signal, and use the known spatial relationship between the MIMO platform and the communication receiver to calculate the signal start time of the communication receiver; The complete received communication signal is extracted based on the known pulse code length, and then subjected to a Fourier transform. The normalized frequency points are: Thus, the spectral amplitude can be obtained; According to known coding rules, the spectral amplitude is... The number of points is divided into segments. Each part; The following The absolute sum of the amplitudes of each part of the spectrum is compared with the absolute sum of the amplitudes of the first part of the spectrum; if it is greater than the absolute sum of the amplitudes of the first part of the spectrum, it is decoded as 1; otherwise, it is decoded as 0.

2. The MIMO radar communication integrated waveform design method utilizing spectral amplitude embedded information as described in claim 1, characterized in that, In step S1: Based on the spatial composite power of the transmitted waveform and the desired transmitted pattern, an optimization model for the MIMO array detection waveform is established: in, express The direction of the launch guide vector The first in the space The number of discretized angles is [number], and the total number of discretized angles in the entire space is [number]. , for Weighting coefficients for directional transmit power matching error. The desired radar pattern for the MIMO array. This is a scaling factor used to compensate for the mismatch between the expected and actual radiation patterns. Representation matrix The Line 1 Column elements, This represents the modulo value.

3. The MIMO radar communication integrated waveform design method utilizing spectral amplitude implanted information according to claim 2, characterized in that, In step S4: By combining the MIMO array detection waveform optimization model and the communication waveform optimization model, an integrated waveform optimization model with both detection and communication functions is obtained: in, This is a scale factor used to balance radar detection performance and communication transmission performance. At that time, considering only communication performance, At that time, only radar performance was considered; The transmitted waveform matrix is ​​vectorized, and the non-convex constraint of the synthesized signal spectrum amplitude matching is transformed into a complex fitting error constraint, thus establishing a relaxed integrated waveform optimization model: in, , This indicates that the matrix is ​​straightened by columns; , , for An identity matrix of dimensions Represents the kron product. Represents the conjugate of a matrix or vector; , The phase factor is an auxiliary variable introduced to simplify the problem-solving process.

4. The MIMO radar communication integrated waveform design method utilizing spectral amplitude implantation information as described in claim 3, characterized in that, In step S5, the integrated waveform optimization model is a multivariable nonconvex optimization problem, which is solved using a cyclic algorithm, specifically including: Step S5-1 , and Update at regular intervals : Step S5-2 , and Update at regular intervals : in, Indicates taking the phase; Step S5-3 , and Update at regular intervals : Step S5-4 , and Update at regular intervals : Construct an upper bound function and relax it to be about Quadratic optimization problem: in, , , , for In the The iteration value of the step, ; , , It is a fixed constant. Indicates taking the real part; The quadratic optimization problem can be relaxed into a linear optimization problem under equality constraints using the MM algorithm: in, , , Represents vector matrix representation, It is a vector of all 1s of the corresponding dimension; , ; , and At a certain time, The optimal value is ; make Repeated calculation Until the change value of the original objective function of the integrated waveform meets the preset threshold; Step S5-5, iterate through steps S5-1 to S5-4, and solve alternately. , , and The iteration continues until the change value of the original objective function meets the preset threshold, at which point the iteration stops and the optimal transmission waveform for MIMO radar-communication integration is obtained.

5. A MIMO radar communication integrated waveform design system utilizing spectral amplitude-embedded information, characterized in that, The system includes a processing unit configured to perform the following steps: Step S1: Based on prior knowledge of the radar target distribution airspace, establish a detection waveform optimization model based on the power matching criterion; In step S1: The transmit waveform matrix of the MIMO array is ;in, Indicates the first The transmitted waveform of each sub-pulse The number of transmitting array elements, The number of sub-pulses; MIMO arrays in far-field space The synthesized signal power at the location is ;in, Represents the transpose of a matrix or vector. Represents the conjugate transpose of a matrix or vector. This represents the sum of squares of all elements of the vector. express The launch steering vector in the direction; Step S2: Based on the communication information implantation rules, determine the expected spectral amplitude of the synthesized signal of the MIMO array transmit waveform in the direction of the communication receiver; In step S2: by The amplitude spectrum at each frequency point transmits one bit of information, and the spectrum of the entire synthesized signal is divided into... Each part; The desired spectral amplitude is divided into three levels, the first... The spectral amplitude value of each reference frequency point is For the spectral amplitude of subsequent frequency points, if the transmission is 0, then the corresponding... The spectral amplitude value of each frequency point If 1 is transmitted, then the corresponding The spectral amplitude value of each frequency point ; The expected spectral amplitude of the synthesized signal in the direction of the communication receiver by the MIMO array during the radar pulse is: ; Step S3: Based on the expected spectral amplitude of the synthesized signal in the direction of the communication receiver, establish a communication waveform optimization model based on error energy constraints; In step S3: The space-based self-communication receiver is located in the far field direction of the MIMO array. At the location, the synthesized signal at the communication receiver is ,in, The corresponding directional guide vector; The spectrum is obtained by performing a Fourier transform on the synthesized signal. ;in, , Indicates a multiple of the fundamental frequency; Based on the synthesized signal spectrum, a communication waveform optimization model for the MIMO array is established: in, This is a scaling factor used to mitigate the matching error between the synthesized signal's spectral amplitude and the desired spectral amplitude. Indicates the amplitude of the received signal spectrum of the communication device. Weighting coefficients for matching errors at each frequency point; Step S4: Establish an integrated waveform relaxation optimization model for MIMO radar communication; Step S5: Solve the dual-function integrated waveform optimization model under constant modulus constraints based on the cyclic algorithm and the MM algorithm; Step S6: The communication receiver decodes the synthesized signal based on the spectrum amplitude segment summation criterion to complete the communication information transmission with the multifunctional electronic information system; In step S6, The spectrum of the synthesized signal intercepted by the communication receiver is ;in, The spectrum of Gaussian white noise inside the receiver. , as an auxiliary variable For phase factor; Record the start time of the MIMO array's transmitted signal, and use the known spatial relationship between the MIMO platform and the communication receiver to calculate the signal start time of the communication receiver; The complete received communication signal is extracted based on the known pulse code length, and then subjected to a Fourier transform. The normalized frequency points are: Thus, the spectral amplitude can be obtained; According to known coding rules, the spectral amplitude is... The number of points is divided into segments. Each part; The following The absolute sum of the amplitudes of each part of the spectrum is compared with the absolute sum of the amplitudes of the first part of the spectrum; if it is greater than the absolute sum of the amplitudes of the first part of the spectrum, it is decoded as 1; otherwise, it is decoded as 0.

6. An electronic device, characterized in that, The electronic device includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, it implements the steps of the MIMO radar communication integrated waveform design method according to any one of claims 1-4.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the MIMO radar communication integrated waveform design method according to any one of claims 1-4, which utilizes spectral amplitude-embedded information.

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