A radar-communication integrated design method and device based on power domain multiplexing

Abstract

The application discloses a radar communication integrated design method and device based on power domain multiplexing, which comprises the following steps: superimposing a radar signal and a communication signal in a time-frequency domain to serve as a radar communication integrated signal; processing the radar signal of the radar communication integrated signal received by a communication receiving end through a time delay frequency difference estimation algorithm, removing the estimated radar signal, separating out the communication signal, and demodulating the communication signal; and directly taking the radar communication integrated signal received by a radar receiving end as a radar signal to perform target detection, so that the purpose of hiding communication information is achieved by hiding the communication signal in the radar transmitting signal; the radar transmitter and the signal processor do not need to be changed, only one more step of removing the radar signal through the time delay frequency difference estimation algorithm is needed for the communication processing system, the change of the whole system is small, the radar and the communication are shared in the time domain and the frequency domain, and the resource utilization rate is effectively improved.

Description

Technical Field

[0001] This invention relates to a radar-communication integrated design method and device based on power domain multiplexing, belonging to the field of radar and communication technology. Background Technology

[0002] With the continuous development of technology, in order to meet the needs of modern warfare command and control, various reconnaissance, jamming, detection, and communication equipment need to be installed on the same platform. These devices improve the overall performance of the combat platform to a certain extent and affect the platform's continuous combat time. In terms of space, the overall space is limited, and the increase in various devices will encroach on the remaining space. In terms of concealment, since the equipment needs to have its own relatively independent antenna to work, the different infrared characteristics of various devices increase the probability of being detected.

[0003] With the development of millimeter-wave radar and 5G and even future 6G wireless communication, the operating frequency bands of radar and communication are gradually converging, which lays the foundation for the realization of digital antennas for radar and communication. In addition, both radar and communication can perform digital signal processing, thus promoting the sharing of digital signal processors between radar and communication.

[0004] In terms of hardware, radar and communication have already achieved integration. However, to achieve deeper integration, the key lies in the design of the integrated waveform. Radar-communication integrated waveform refers to using a single waveform to achieve both radar and communication functions. Functionally, radar primarily aims to detect and sense targets, while communication mainly transmits information. There are two design methods for shared waveforms in radar-communication integration. One is waveform multiplexing, which combines radar and communication waveforms in a certain dimension using multiplexing technology and transmits them. The received waveform can then be separated into radar and communication waveforms through signal processing. Shared waveform design based on waveform multiplexing can separate radar and communication signals in a certain dimension, avoiding mutual interference and being easy to design, but at the cost of low resource utilization. The other method is waveform sharing, which uses only one waveform and can achieve both radar target detection and communication signal transmission at the receiving end through different signal processing methods. Shared waveform design based on waveform sharing can efficiently utilize system resources but requires new processing methods and may result in some performance degradation.

[0005] Therefore, existing technologies lack an integrated radar and communication design method that can effectively improve resource utilization and solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a radar communication integrated design method and device based on power domain multiplexing, which can effectively improve resource utilization.

[0007] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0008] In a first aspect, the present invention provides an integrated radar communication design method based on power domain multiplexing, comprising:

[0009] Radar and communication signals are superimposed in the time and frequency domains to form an integrated radar and communication signal.

[0010] The radar signal received by the communication receiver is estimated by using a time delay frequency difference estimation algorithm to obtain the estimated radar signal.

[0011] The estimated radar signal is removed from the integrated radar and communication signal received by the communication receiver, the communication signal is separated, and the communication signal is demodulated.

[0012] The radar-communication integrated signal received by the radar receiver is directly used as a radar signal for target detection.

[0013] Furthermore, the superposition of transmitted radar signals and communication signals in the time and frequency domains to form an integrated radar-communication signal is described by the following formula:

[0014] Sa(t)=P ra u(t)+P com k(t) (1)

[0015] Where Sa(t) is the transmitted radar-communication integrated signal, u(t) is the radar signal used for target detection, and P ra Let P be the radar transmit power, k(t) be the communication signal used for communication transmission, and P be the signal transmitted by the radar. com This refers to the communication transmission power.

[0016] Furthermore, the step of estimating the radar signal using a time delay frequency difference estimation algorithm to obtain the estimated radar signal includes:

[0017] The radar-communication integrated signal r(t) and radar signal u(t) received from the communication receiver and transmitted from the transmitter are used to estimate the time delay and frequency difference using a time delay-frequency difference estimation algorithm, thus obtaining the time delay estimation result. Estimation results of frequency difference

[0018] Using the time delay estimation results Estimation results of frequency difference The estimated radar signal was obtained.

[0019] Furthermore, the radar-communication integrated signal r(t) received from the communication receiver and transmitted from the transmitter station, along with the radar signal u(t), are used to estimate the time delay and frequency difference using a time delay-frequency difference estimation algorithm, thereby obtaining the time delay estimation result. Estimation results of frequency difference include:

[0020] The time delay and frequency difference are estimated using the radar-communication integrated signal r(t) received from the communication receiver and transmitted from the transmitter station, along with the radar signal u(t), through a fuzzy function. The time delay estimation result is then obtained. Coarse estimation results of frequency difference The formula is as follows:

[0021]

[0022] Where τ and f represent time delay and frequency difference, respectively, the estimated time delay is calculated based on τ and f when |A(τ,f)| reaches its maximum value. and frequency difference T is the duration of the transmitted signal, and max[·] represents the maximum value of the function. * | represents the conjugate of the signal, and |·| represents the absolute value of the signal;

[0023] Using the estimation results of the radar-communication integrated signal r(t), radar signal u(t), and time delay received from the communication receiver and transmitted from the transmitter, the radar signal u(t) is used as the basis for the calculation. The input signal d(n) calculated using the Amplitude Phase Estimation (APES) algorithm is as follows:

[0024]

[0025] Among them, F s Let N be the sampling frequency of the signal, and N be the number of sampling points of the input signal, satisfying N = T × F s ;

[0026] Using the coarse estimation results of the input signal d(n) and the frequency difference Estimate the noise covariance matrix of the signal. The formula is as follows:

[0027]

[0028] in, y l =[d(l) d(l+1)...d(l+M-1)] T , [·] T L represents the transpose of the matrix, L = N - M + 1 represents the total number of snapshots of the time series, and M is the order of the Finite Impulse Response (FIR) filter in the APES algorithm. This indicates the range of values ​​for the estimated frequency difference;

[0029] Using the estimated noise covariance The amplitude spectrum estimate of the APES algorithm is calculated by using the maximum value of the amplitude spectrum. The precise estimation results of the frequency difference are obtained. in The formula is as follows:

[0030]

[0031] Where a(ω)=[1 e jω e j2ω ...e j(M-1)ω ] T ,(·) H This indicates taking the conjugate transpose of the matrix, (·). -1 This indicates taking the inverse of the matrix.

[0032] Furthermore, the estimation results utilizing time delay Estimation results of frequency difference The estimated radar signal was obtained. The formula is as follows:

[0033]

[0034] Furthermore, the estimated radar signal is eliminated from the radar-communication integrated signal r(t) received from the communication receiver. The communication signal e(t) is separated out, as shown in the following formula:

[0035]

[0036] Where e(t) is the modulated communication signal, and W(t) is the weight vector of the signal separation algorithm at time t.

[0037] Furthermore, the signal separation algorithm employs the least mean square algorithm, and the calculation formula is as follows:

[0038]

[0039] Where μ is the step size, typically 0 < μ < 1 / λ max , λ max For the estimated radar signal The largest eigenvalue of the autocorrelation matrix, W(t), is obtained by iterative calculation at time t-1, with an initial value of W(0) = 0. The weight vector of the minimum mean square algorithm at time t+1 is calculated iteratively.

[0040] 8. A radar-communication integrated design device based on power domain multiplexing, characterized in that it comprises:

[0041] The transmitting module is used to superimpose radar signals and communication signals in the time and frequency domains to form an integrated radar and communication signal.

[0042] The estimation module is used to estimate the radar signal received by the communication receiver using a time delay frequency difference estimation algorithm, and obtain the estimated radar signal.

[0043] The communication signal separation module is used to remove the estimated radar signal from the integrated radar and communication signal received by the communication receiver, separate the communication signal, and perform communication signal demodulation.

[0044] The radar signal processing module is used to directly treat the radar communication integrated signal received by the radar receiver as a radar signal for target detection.

[0045] Secondly, the present invention provides an integrated radar communication design device based on power domain multiplexing, comprising:

[0046] The transmitting module is used to superimpose radar signals and communication signals in the time and frequency domains to form an integrated radar and communication signal.

[0047] The communication signal separation module is used to process the radar signal received by the communication receiver using a time delay frequency difference estimation algorithm, remove the estimated radar signal, separate the communication signal, and demodulate the communication signal.

[0048] The radar signal processing module is used to directly treat the radar communication integrated signal received by the radar receiver as a radar signal for target detection.

[0049] Thirdly, the present invention provides an electronic device, including a processor and a storage medium;

[0050] The storage medium is used to store instructions;

[0051] The processor is configured to operate according to the instructions to perform the steps of the method according to any of the preceding claims.

[0052] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the preceding methods.

[0053] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0054] This invention provides a radar-communication integrated design method and device based on power domain multiplexing. By embedding the communication signal in the radar transmitted signal, the purpose of concealing communication information can be achieved. Furthermore, it does not require changes to the radar transmitter, receiver, or signal processor. For the communication processing system, only an additional step is needed to remove the radar signal using a time delay frequency difference estimation algorithm, which does not significantly change the overall system. Moreover, the radar and communication achieve time and frequency domain sharing, effectively improving resource utilization. Attached Figure Description

[0055] Figure 1 This is a flowchart of a radar-communication integrated design method based on power domain multiplexing provided by an embodiment of the present invention;

[0056] Figure 2 This is a time delay profile diagram of the coarse estimation result of the communication receiver provided in the embodiment of the present invention;

[0057] Figure 3 This is a Doppler profile of the coarse estimation result of the communication receiver provided in the embodiment of the present invention;

[0058] Figure 4 This is a schematic diagram of the signal spectrum of the precise frequency difference estimation result of the communication receiver provided in the embodiment of the present invention;

[0059] Figure 5 This is a schematic diagram of moving target detection based on the precise estimation result of the frequency difference at the communication receiver provided in an embodiment of the present invention;

[0060] Figure 6 This is a schematic diagram of the target detection results at the radar receiver provided in an embodiment of the present invention;

[0061] Figure 7 This is a schematic diagram showing the bit error rate of communication signals as the radar signal-to-noise ratio changes, provided in an embodiment of the present invention. Detailed Implementation

[0062] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0063] Example 1

[0064] This embodiment introduces a radar-communication integrated design method based on power domain multiplexing, including:

[0065] Radar and communication signals are superimposed in the time and frequency domains to form an integrated radar and communication signal.

[0066] The radar signal received by the communication receiver is estimated by using a time delay frequency difference estimation algorithm to obtain the estimated radar signal.

[0067] The estimated radar signal is removed from the integrated radar and communication signal received by the communication receiver, the communication signal is separated, and the communication signal is demodulated.

[0068] The radar-communication integrated signal received by the radar receiver is directly used as a radar signal for target detection.

[0069] like Figure 1 As shown in the figure, the integrated radar-communication design method based on power domain multiplexing provided in this embodiment involves the following steps in its application process:

[0070] Step 1: A transmitting station that requires radar detection and communication transmission transmits radar detection and communication signals in the time and frequency domain as an integrated radar and communication signal.

[0071] The transmitting station superimposes radar detection and communication signals in the time-frequency domain and transmits them as an integrated radar-communication signal, as follows:

[0072] Sa(t)=P ra u(t)+P com k(t) (1)

[0073] Where Sa(t) is the transmitted radar-communication integrated signal, u(t) is the radar signal used for target detection, which can be arbitrarily selected according to the detection mission, and P ra Let P be the radar transmit power, k(t) be the communication signal used for communication transmission, and P be the signal transmitted by the radar. com This refers to the communication transmission power.

[0074] Step 2: After receiving the integrated radar and communication signal from the communication receiver, the estimated radar signal is removed by the time delay frequency difference estimation algorithm, the communication signal is separated, and the communication signal is demodulated.

[0075] Specifically, it includes:

[0076] Step 2.1: The radar-communication integrated signal r(t) and radar signal u(t) received from the communication receiver and transmitted from the transmitter are used to estimate the time delay and frequency difference using a time delay-frequency difference estimation algorithm, thus obtaining the time delay estimation result. Estimation results of frequency difference

[0077] The specific time delay frequency difference estimation method can be arbitrarily selected according to the actual situation, and a joint algorithm of fuzzy function and APES can be used.

[0078] First, the time delay and frequency difference are estimated using the radar-communication integrated signal r(t) and radar signal u(t) received from the communication receiver and transmitted from the transmitter station through a fuzzy function, thus obtaining the time delay estimation result. Coarse estimation results of frequency difference The formula is as follows:

[0079]

[0080] Where τ and f represent time delay and frequency difference, respectively, the estimated time delay can be calculated based on τ and f when |A(τ,f)| reaches its maximum value. and frequency difference T is the duration of the transmitted signal, and max[·] represents the maximum value of the function. * represents taking the conjugate of the signal, and |·| represents taking the absolute value of the signal.

[0081] Secondly, the estimation results of the radar-communication integrated signal r(t), radar signal u(t), and time delay received from the communication receiver and transmitted from the transmitter are used. The input signal d(n) calculated using the APES algorithm is as follows:

[0082]

[0083] Among them, F s Let N be the sampling frequency of the signal, and N be the number of sampling points of the input signal, satisfying N = T × F s .

[0084] Next, the coarse estimation results of the input signal d(n) and frequency difference are used. Estimate the noise covariance matrix of the signal. The formula is as follows

[0085]

[0086] in, y l =[d(l) d(l+1)...d(l+M-1)] T , [·] T This represents taking the transpose of the matrix, L = N - M + 1, which represents the total number of snapshots taken of the time series, and M is the order of the FIR filter in the APES algorithm. This indicates the range of estimated frequency difference values, which is generally the Doppler resolution unit of the fuzzy function frequency difference estimation.

[0087] Finally, the estimated noise covariance is used. The amplitude spectrum estimate of the APES algorithm is calculated by using the maximum value of the amplitude spectrum. The precise estimation results of the frequency difference are obtained. The formula is as follows:

[0088]

[0089] Where a(ω)=[1 e jω ej2ω ...e j(M-1)ω ] T ,(·) H This indicates taking the conjugate transpose of the matrix, (·). -1 This indicates taking the inverse of the matrix.

[0090] Formula - uses a joint algorithm of fuzzy function and APES, but is not limited to this method and can be any type of time delay frequency difference estimation algorithm.

[0091] Step 2.2 Utilize the time delay estimation results Estimation results of frequency difference The estimated radar signal was obtained.

[0092]

[0093] Step 2.3 Eliminate the estimated radar signal from the radar-communication integrated signal r(t) received from the communication receiver. The communication signal e(t) is separated out, as shown in the following formula:

[0094]

[0095] Where e(t) is the modulated communication signal, and W(t) is the weight vector of the least mean square algorithm at time t, obtained iteratively from the previous time (i.e., time t-1), with an initial value of W(0) = 0. The weight vector of the least mean square algorithm at the next time (i.e., time t+1) can be iteratively calculated as follows:

[0096]

[0097] Where μ is the step size, typically 0 < μ < 1 / λ max , λ max For the estimated radar signal The largest eigenvalue of the autocorrelation matrix.

[0098] In the formula, the least mean square algorithm is used, but it is not limited to this method and can be any type of signal separation algorithm.

[0099] Step 2.4 involves demodulating the separated communication signal e(t).

[0100] Step 3. After receiving the integrated radar and communication signal at the radar receiver, treat it directly as a radar signal for target detection.

[0101] The following description, in conjunction with a preferred embodiment, illustrates the content involved in the above embodiments.

[0102] Experimental Scenario: The transmitting station transmits a radar-communication integrated signal based on power domain multiplexing. The radar signal uses linear frequency modulation (LFM), and the communication signal uses orthogonal frequency division multiplexing (OFDM). The radar signal bandwidth B is 6.4 MB, and the pulse width T is 50 μs. The communication signal uses orthogonal phase shift keying (QPSK) with 2250 subcarriers N. The pulse repetition frequency (PRF) of the radar-communication integrated signal is 3 kHz, the center frequency F0 is 10 GHz, and the transmit power is 500 W. A target exists within the radar's detection area, 10 km away from the radar, with a speed of 280 m / s and a radar cross-section of 5 m². 2 The pulse repetition period M is 64, and the noise figure is 1.5dB. The communication receiver is 3km from the transmitting station, and its speed is 150m / s. Based on the set parameters, simulate the integrated waveform of the transmission.

[0103] (1) When receiving the integrated radar and communication signal at the communication receiver, make the radar signal signal-to-noise ratio 22dB and the communication signal signal-to-noise ratio 11dB, and perform radar target detection and communication bit error rate measurement using the integrated system based on power domain multiplexing.

[0104] When receiving integrated radar and communication signals at the communication receiver, the signal-to-noise ratio (SNR) of the communication signal remains constant at 11 dB. The radar SNR is then varied, and the communication bit error rate under different SNRs is calculated.

[0105] Experimental results:

[0106] (1) From Figure 2 , Figure 3 From this, we can obtain the time delay and frequency difference values ​​when performing a coarse estimation using a fuzzy function at the communication receiver. Figure 4 , Figure 5 From this, we can obtain the frequency difference value when performing a fine estimation using APES spectral estimation. Figure 6 The results can be seen from the radar receiver after testing.

[0107] Table 1 shows that the measured target distance, velocity, and angle are almost equal to the actual values, and the measured results fully meet the requirements of radar target detection; the bit error rate of the communication signal also conforms to the current signal-to-noise ratio. Therefore, the designed radar-communication integrated system based on power domain multiplexing performs well.

[0108] Table 1 shows the target measurement values ​​and communication signal bit error rate obtained after processing.

[0109]

[0110] (2) If the communication signal-to-noise ratio remains unchanged, and only the radar signal-to-noise ratio is changed, due to the inherent error in time delay and frequency shift estimation, a portion of the radar signal will remain in the separated communication signal. If this portion of the radar signal is also treated as noise, the separated communication signal-to-noise ratio will be smaller than the set communication bit error rate. Furthermore, the actual communication signal-to-noise ratio is also related to the radar signal-to-noise ratio. Figure 7 It can be observed that as the radar signal-to-noise ratio increases, the communication bit error rate tuning results worsen. In practice, a balance needs to be found that can improve the security of communication signals while ensuring better demodulation performance.

[0111] Example 2

[0112] This embodiment provides an integrated radar and communication design device based on power domain multiplexing, including:

[0113] The transmitting module is used to superimpose radar signals and communication signals in the time and frequency domains to form an integrated radar and communication signal.

[0114] The communication signal separation module is used to process the radar signal received by the communication receiver using a time delay frequency difference estimation algorithm, remove the estimated radar signal, separate the communication signal, and demodulate the communication signal.

[0115] The radar signal processing module is used to directly treat the radar communication integrated signal received by the radar receiver as a radar signal for target detection.

[0116] Example 3

[0117] This embodiment provides an electronic device, including a processor and a storage medium;

[0118] The storage medium is used to store instructions;

[0119] The processor is configured to operate according to the instructions to perform the steps of the method according to any one of Embodiment 1.

[0120] Example 4

[0121] This embodiment provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the methods described in Embodiment 1.

[0122] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A radar-communication integrated design method based on power domain multiplexing, characterized in that, include: Radar and communication signals are superimposed in the time and frequency domains to form an integrated radar and communication signal. Utilizing the radar-communication integrated signal received by the communication receiver and radar signals The time delay and frequency difference are estimated using a fuzzy function, yielding the time delay estimate. Coarse estimation results of frequency difference The formula is as follows: in Representing time delay and frequency difference respectively, according to Reaching the maximum value Calculate the estimated time delay you are looking for. and frequency difference , The duration of the transmitted signal. This is represented as the maximum value of the function. Indicates the conjugate of the signal. This indicates taking the absolute value of the signal; Utilizing the integrated radar and communication signals received from the transmitting station at the communication receiver Radar signals And the estimation results of time delay Calculate the input signal using the APES algorithm. The formula is as follows: in, The sampling frequency of the signal. The number of sampling points for the input signal, satisfying ; Using input signal Coarse estimation results of frequency difference Estimate the noise covariance matrix of the signal. The formula is as follows: in, , , This represents taking the transpose of the matrix. , representing the total number of snapshots taken of the time series, where M is the order of the FIR filter in the APES algorithm. This indicates the range of values ​​for the estimated frequency difference; Using the estimated noise covariance The amplitude spectrum estimate of the APES algorithm is calculated by using the maximum value of the amplitude spectrum. The precise estimation results of the frequency difference are obtained. ,in The formula is as follows: in , This represents taking the conjugate transpose of a matrix. This indicates taking the inverse of the matrix; Using the time delay estimation results Estimation results of frequency difference The estimated radar signal was obtained. ; The estimated radar signal is removed from the integrated radar and communication signal received by the communication receiver, the communication signal is separated, and the communication signal is demodulated. The radar-communication integrated signal received by the radar receiver is directly used as a radar signal for target detection.

2. The radar-communication integrated design method based on power domain multiplexing according to claim 1, characterized in that, The formula for superimposing radar and communication signals in the time and frequency domains to form an integrated radar-communication signal is as follows: in, It is a transmitted radar and communication integrated signal. For radar signals used for target detection, For radar transmission power, For communication signals used in communication transmission, This refers to the communication transmission power.

3. The radar-communication integrated design method based on power domain multiplexing according to claim 1, characterized in that, The estimation results using time delay Estimation results of frequency difference The estimated radar signal was obtained. The formula is as follows: 。 4. The radar-communication integrated design method based on power domain multiplexing according to claim 3, characterized in that, The radar-communication integrated signal received from the communication receiver Elimination of estimated radar signals Separate the communication signal The formula is as follows: in, For the modulated communication signal, for The weight vector of the time-signal separation algorithm.

5. The radar-communication integrated design method based on power domain multiplexing according to claim 4, characterized in that, The signal separation algorithm uses the least mean square algorithm, and the calculation formula is as follows: in, Step size, , For the estimated radar signal The largest eigenvalue of the autocorrelation matrix Depend on The initial value is obtained through iterative calculation at each time step. =0, iteratively calculated The weight vector of the least mean square algorithm at time step 1.

6. A radar-communication integrated design device based on power domain multiplexing, used to implement the radar-communication integrated design method based on power domain multiplexing as described in claim 1, characterized in that, include: The transmitting module is used to superimpose radar signals and communication signals in the time and frequency domains to form an integrated radar and communication signal. The estimation module is used to estimate the radar signal received by the communication receiver using a time delay frequency difference estimation algorithm, and obtain the estimated radar signal. The communication signal separation module is used to remove the estimated radar signal from the integrated radar and communication signal received by the communication receiver, separate the communication signal, and perform communication signal demodulation. The radar signal processing module is used to directly treat the radar communication integrated signal received by the radar receiver as a radar signal for target detection.

7. An electronic device, characterized in that: Including processor and storage media; The storage medium is used to store instructions; The processor is configured to operate according to the instructions to perform the steps of the method according to any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When executed by a processor, the program implements the steps of the method according to any one of claims 1 to 5.

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