A method for suppressing moving target echo interference of a full-duplex communication and sensing integrated system

Abstract

The application discloses a moving target echo interference suppression method of a full-duplex sensing integrated system, and comprises the following steps: S1. signal transmission and reception are performed to suppress static self-interference signals; S2. OFDM radar processing based on a periodogram is performed on the signals after self-interference suppression to obtain an initial ambiguity function, and delay / Doppler information of moving target echoes is extracted; S3. targets are numbered according to target echo power, and a termination threshold is set; S4. the absolute value of the ambiguity function is compared with the termination threshold; S5. reconstruction of the first target echo is performed to obtain the first iteration signal; S6. the ambiguity function of the first iteration is obtained; S7. steps S4-S6 are repeatedly executed until the maximum value of the absolute value of the ambiguity function is smaller than the termination threshold, and finally, the output signal is obtained. The application enables the receiver to suppress static self-interference of the same frequency at the same time, and to decouple moving target echo signals and uplink communication signals of the same frequency at the same time, so as to extract sensing information and uplink communication information.

Description

Technical Field

[0001] This invention relates to the field of communications, and in particular to a method for suppressing moving target echo interference in a full-duplex integrated inductive system. Background Technology

[0002] With the increasing use of wireless communication spectrum leading to escalating spectrum conflicts between radar and communication systems, and with the growing demand for high communication capacity and reliable sensing capabilities from many emerging applications such as connected vehicles, smart homes, and industrial IoT, integrating sensing functions into 6G wireless networks has become a consensus in academia and industry. Considering spectrum efficiency, equipment cost, and technical feasibility, the industry's demand for Integrated Sensing and Communications (ISAC) technology is constantly increasing. As the main waveform in 4G and 5G wireless networks, Orthogonal Frequency Division Multiplexing (OFDM) waveforms, with their high spectrum efficiency, low implementation complexity, and good sensing performance, are highly likely to play an important role in next-generation 6G wireless networks.

[0003] Compared to other integrated sensing systems, the integrated sensing system that combines simultaneous full-duplex communication and sensing at the same frequency offers higher spectral efficiency and lower communication and sensing latency. Specifically, the base station of this full-duplex sensing system simultaneously performs full-duplex communication at the same frequency and uses the echo of the downlink communication signal to sense the target within the same frequency band. However, this simultaneous full-duplex operation introduces significant interference at the base station receiver. Besides direct self-interference signals from the transmitter to the receiver and multipath self-interference, the mutual interference between the target echo and the uplink communication signal will affect the system's sensing and communication performance. Therefore, at the receiver, suppressing self-interference and decoupling the target echo and the uplink communication signal becomes a key design challenge for the full-duplex sensing system. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for suppressing moving target echo interference in a full-duplex integrated sensing system, so that the receiver can suppress static self-interference at the same frequency and decouple the moving target echo signal and the uplink communication signal at the same frequency to extract sensing information and uplink communication information.

[0005] The objective of this invention is achieved through the following technical solution: a method for suppressing moving target echo interference in a full-duplex sensing integrated system, wherein the full-duplex sensing integrated system includes a single-antenna full-duplex OFDM sensing integrated transmitter, a single-antenna full-duplex OFDM sensing integrated receiver, a downlink user, a static object, a sensing target, and an uplink user;

[0006] The full-duplex OFDM inductive integrated transmitter is used to transmit continuous OFDM signals, which serve as downlink ISAC signals and have the following function:

[0007] (1) As a downlink communication signal, it undertakes the downlink communication function from the base station to the downlink user;

[0008] (2) As a radar detection signal, it transmits signals to dynamically sensed targets;

[0009] The signals received by the full-duplex OFDM integrated inductive receiver include:

[0010] (1) Uplink communication signals transmitted by uplink users;

[0011] (2) The echo of a moving target reflected by a dynamically sensed target;

[0012] (3) Direct self-interference signal leaked by OFDM full-duplex inductive integrated transmitter;

[0013] (4) Multipath self-interference echoes reflected by static objects in the environment;

[0014] Among them, (3) and (4) are static self-interference signals;

[0015] The method includes the following steps:

[0016] S1. The full-duplex OFDM inductive integrated transmitter transmits OFDM continuous signals for target perception and downlink communication, and the uplink user transmits OFDM continuous signals for uplink communication. The full-duplex OFDM inductive integrated receiver receives the signals and performs front-end processing to suppress static self-interference signals.

[0017] S2. Perform OFDM radar processing based on periodograms on the signal after self-interference suppression to obtain the initial ambiguity function Λ. (0) (τ,f D ), and extract the delay / Doppler information of the target echo;

[0018] S3. Number the targets according to their echo power and set a termination threshold;

[0019] Initialize the number of iterations Number of iterations Corresponding fuzzy function That is, the initial fuzzy function Λ (0) (τ,f D );

[0020] S4. Relate the termination threshold Γ to the iteration count. fuzzy function The maximum absolute value is compared; if the maximum value is greater than the termination threshold, the next step is executed; otherwise, the loop is terminated and a signal is output.

[0021] S5. Estimating the first The time delay and Doppler shift of each target are used to perform the first... Reconstruction of the target echo and acquisition of the first target echo The next iteration signal;

[0022] S6. To Sub-iteration signal Perform OFDM radar processing based on periodic diagrams to obtain the first... The fuzzy function of the next iteration;

[0023] S7. Order Soon The value is updated to Repeat steps S4 to S6 until the maximum value of the absolute value of the fuzzy function is less than the termination threshold, and obtain the final output signal.

[0024] The beneficial effects of the present invention are: 1. The present invention can perform simultaneous full-duplex communication and target sensing at the same frequency, that is, during full-duplex communication, the target is sensed at the same time and on the same frequency band, which improves spectrum efficiency and reduces the latency of communication and sensing.

[0025] 2. Compared with the integrated sensing system that utilizes multi-antenna beamforming, this system greatly saves equipment costs, reduces equipment size, and lowers equipment power consumption;

[0026] 3. The target interference suppression method proposed in this invention has low implementation complexity and can reuse OFDM radar processing modules to calculate ambiguity functions;

[0027] 4. The target interference suppression method proposed in this invention has a high degree of compatibility with OFDM receivers and can be well integrated into OFDM sensing systems. Attached Figure Description

[0028] Figure 1 This is a schematic diagram illustrating the overall principle of the present invention;

[0029] Figure 2 A schematic diagram illustrating the principle of suppressing echo interference from moving targets;

[0030] Figure 3This is a flowchart of the frequency domain processing for a full-duplex integrated inductive receiver.

[0031] Figure 4 A schematic diagram of the power spectral density and constellation diagram of a full-duplex integrated inductive receiver at different interference suppression stages;

[0032] Figure 5 A schematic diagram illustrating the sensing performance of a full-duplex integrated sensing system;

[0033] Figure 6 This is a schematic diagram showing the relationship between interference suppression performance and input echo interference-to-noise ratio.

[0034] Figure 7 This is a schematic diagram illustrating the performance of demodulating uplink communication signals in a full-duplex integrated sensing system. Detailed Implementation

[0035] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0036] This invention is a full-duplex OFDM integrated sensing system based on a single-receive, single-transmit antenna. The overall system structure is as follows: Figure 1 As shown. The main task is to design the digital baseband processing flow of a full-duplex integrated sensing receiver, enabling the receiver to suppress simultaneous static self-interference at the same frequency and decouple simultaneous moving target echo signals and uplink communication signals at the same frequency, so as to extract sensing information and uplink communication information.

[0037] The full-duplex sensing integrated system includes a single-antenna full-duplex OFDM sensing integrated transmitter, a single-antenna full-duplex OFDM sensing integrated receiver, downlink users, static objects, sensing targets, and uplink users.

[0038] The full-duplex OFDM inductive integrated transmitter is used to transmit continuous OFDM signals, which serve as downlink ISAC signals and have the following function:

[0039] (1) As a downlink communication signal, it undertakes the downlink communication function from the base station to the downlink user;

[0040] (2) As a radar detection signal, it transmits signals to dynamically sensed targets;

[0041] The signals received by the full-duplex OFDM integrated inductive receiver include:

[0042] (1) Uplink communication signals transmitted by uplink users;

[0043] (2) The echo of a moving target reflected by a dynamically sensed target;

[0044] (3) Direct self-interference signal leaked by OFDM full-duplex inductive integrated transmitter;

[0045] (4) Multipath self-interference echoes reflected by static objects in the environment;

[0046] Among them, (3) and (4) are static self-interference signals;

[0047] The full-duplex OFDM inductive integrated transmitter includes a transmitting antenna, a modulation module, a time-frequency conversion module, a cyclic prefix module, a digital-to-analog converter, and an up-conversion module. The transmitted bits are modulated by the modulation module, and then sequentially pass through the time-frequency conversion module, the cyclic prefix module, the digital-to-analog converter, and the up-conversion module before being transmitted to the transmitting antenna of the full-duplex OFDM inductive integrated transmitter for transmission.

[0048] The full-duplex OFDM inductive integrated receiver includes a receiving antenna, a front-end processing module, a frequency domain differential suppression module, a moving target echo interference suppression module, an OFDM radar processing module, and an uplink communication signal demodulation module. The front-end processing module includes a radio frequency interference cancellation module, a down-conversion module, an analog-to-digital converter, a cyclic prefix removal module, and a time-frequency conversion module. The signal received by the receiving antenna is first subjected to self-interference cancellation with the up-conversion output signal from the full-duplex OFDM inductive integrated transmitter in the radio frequency interference cancellation module. Then, it sequentially passes through the down-conversion module, analog-to-digital converter, cyclic prefix removal module, and time-frequency conversion module before being transmitted to the frequency domain differential suppression module. The signal processing module utilizes the time-invariant characteristics of static self-interference to perform differential operations on the frequency domain signal along the same subcarrier position of different OFDM symbols to obtain a frequency domain differential sequence. Then, a smoothing operation is performed on the differential sequence to suppress static self-interference signals, and the desired uplink communication signal and the sum of the moving target echo signal are output. Next, OFDM radar processing is performed based on the OFDM radar processing module to calculate the delay / Doppler frequency shift, and multiple iterations are performed in the moving target echo interference suppression module to obtain the final output signal (steps 5-9 in the following flowchart). This signal is then transmitted to the uplink communication signal demodulation module for demodulation to complete the uplink communication signal reception.

[0049] 1. Signal transmission and reception process of a single-transmit / receive antenna full-duplex inductive integrated system:

[0050] 101. The OFDM integrated transmitter transmits a continuous OFDM signal via a single transmitting antenna. This signal serves as a downlink ISAC signal and has two functions: (1) as a downlink communication signal, undertaking the downlink communication function from the base station to the downlink user; (2) as a radar detection signal, sensing the delay / Doppler (corresponding to the target's distance / velocity) information. Additionally, the uplink user transmits a continuous OFDM signal for uplink communication.

[0051] 102. At the OFDM inductive receiver, four types of signals are received: (1) uplink communication signals transmitted by uplink users; (2) moving target echoes reflected by dynamically sensed targets (such as vehicles and pedestrians); (3) direct self-interference signals leaked by the OFDM inductive transmitter; and (4) multipath self-interference echoes reflected by static objects in the environment. Among them, (3) and (4) are collectively referred to as static self-interference signals.

[0052] 103. The received signal is converted into a frequency domain signal by the receiver's time-frequency conversion module. The frequency domain signal of the m-th OFDM symbol and the n-th subcarrier is represented as R. n,m where n = 0, 1, ..., N c -1, m = 0, 1, ..., N s -1, N c With N s These represent the number of subcarriers in an OFDM symbol and the number of OFDM symbols, respectively. First, static self-interference suppression is applied to the signal. Figure 1 The static self-interference suppression module in the code is a frequency domain differential interference suppression module. This module utilizes the time-invariant characteristics of static self-interference to suppress frequency domain signals R. n,m Differential operations are performed on subcarriers at the same position along different OFDM symbols to obtain a frequency domain differential sequence; then, a smoothing operation is performed on the differential sequence to suppress static self-interference signals, and the desired uplink communication signal and the sum of the moving target echo signal are output. Alternatively, the structure in the invention patent (publication number CN116243250A) can be directly adopted.

[0053] Figure 2 This is a schematic diagram illustrating the principle of moving target echo interference suppression. The dashed line in the diagram can be considered as a moving target echo interference canceller. Figure 3 The following is a flowchart of the frequency domain processing for a full-duplex inductive receiver, described in detail:

[0054] 2. Considering that OFDM radar has a very high processing gain, typically in the tens of decibels, the following processing can be performed in the presence of uplink communication signal interference:

[0055] 201. Pairs and signals Directly perform OFDM radar processing based on periodograms to obtain the initial ambiguity function Λ. (0) (τ,f D The specific handling is as follows:

[0056] 2011. Corresponding signal matrix Element-wise division is performed to remove the data modulation symbol matrix X of the downlink communication signal. Then, a two-dimensional Fourier transform is performed on the signal with the data symbols removed to obtain the complex periodogram function.

[0057] Where . / represents element-wise division between matrices. Representing the normalized discrete Fourier transform matrix:

[0058] The element in the (k+1)th row and (i+1)th column is k = 0, 1, ..., N c -1, i = 0, 1, ..., N c -1;

[0059] The element in the (k′+1)th row and (i′+1)th column is k′=0,1,...,N s -1,i′=0,1,...,N s -1;

[0060] 2012. On complex periodogram functions By performing mapping, we obtain the initial fuzzy function:

[0061]

[0062] This represents the mapping from a complex periodogram function to a fuzzy function, that is, mapping the grid coordinates representing time delay and Doppler to specific numerical time delay and Doppler coordinates:

[0063] Among them, complex periodic graph functions For N c Line N s The column matrix, specifically the mapping process, is as follows:

[0064] (1) Let the time-delay grid coordinates be represented as n′=0,1,...,N c -1, Doppler grid coordinates are represented as m′=0,1,...,N s -1;

[0065] (2) For any coordinate (n′, m′), the following is performed: Mapping:

[0066] Where Δτ represents the delay resolution, B represents the sensing signal bandwidth; Δf D T represents Doppler resolution. s Indicates the duration of an OFDM symbol;

[0067] Will The element in the (n′+1)th row and the (m′+1)th column is used as the coordinate (n′, m′) to map τ′,(f D The element corresponding to )′ in the initial fuzzy matrix is ​​denoted as Λ.(0) (τ′,(f D )′);

[0068] (3) In n′=0,1,...,N c -1,m′=0,1,...,N s -1, iterate through each coordinate (n′, m′) and repeat (2) for each coordinate, thus obtaining τ′, (f) corresponding to each (n′, m′). D )′ and Λ (0) (τ′,(f D )′), thus forming Λ (0) (τ,f D );

[0069] 202. Detect moving targets and extract the delay / Doppler information of the moving target echo as sensing information:

[0070] Initial fuzzy function Λ (0) (τ,f D (also N) c Line N s A matrix of columns;

[0071] For each coordinate (τ′, (f) D )′), and its corresponding element Λ in the initial fuzzy function matrix. (0) (τ′,(f D The modulus of (τ′) is compared with a preset target detection threshold. If the modulus is greater than the target detection threshold, then (τ′,(f) is considered to be true. D There is a moving target at ()′).

[0072] Suppose a total of P moving targets are detected, and the time delay / Doppler frequency shift of the p-th target is expressed as τ. p ,(f D ) p .

[0073] 3. Definitions before starting the moving target echo interference suppression algorithm

[0074] 301. Assume there are P sensing targets, and the targets are numbered from largest to smallest according to their echo power: 0, 1, 2, ..., P-1.

[0075] 302. Set a termination threshold, defined as follows:

[0076]

[0077] SNR represents the receiver noise average power. threDefined as the target echo signal-to-noise ratio threshold to be suppressed. For example, if the target echo with a signal-to-noise ratio greater than -10dB is to be suppressed, then the SNR... thre =0.1. The number of targets with echo amplitude greater than the threshold Γ is defined as... have

[0078] 4. After OFDM radar processing, the termination threshold Γ will be compared with the first... The fuzzy function of the next iteration The maximum absolute value is compared. If the maximum value is greater than the termination threshold, proceed to the next step; otherwise, jump to step 9, terminate the loop, and output a signal.

[0079] 5. Through the first The fuzzy function of the next iteration The maximum absolute value, estimate the th The time delay and Doppler shift of each target are expressed as follows:

[0080]

[0081] 6. No. The target echo can be reconstructed as in This represents the estimated channel coefficient corresponding to the target echo. X represents the phase rotation caused by time delay and Doppler shift on the nth subcarrier of the m-th OFDM symbol. n,m This represents the data modulation symbol of the downlink communication signal at the m-th OFDM symbol and the n-th subcarrier.

[0082] 601. Utilizing the first Delay estimates for each target Compared with Doppler estimates The reconstructed portion of the target echo signal is shown below.

[0083]

[0084] 602. can be Signal and the Sub-iteration signal The cross-correlation is obtained as follows:

[0085]

[0086] in

[0087] 7. From the first Sub-iteration signal Subtract the first The reconstructed moving target echo signal is obtained. Next iteration signal:

[0088]

[0089] 8. Sub-iteration signal Perform OFDM radar processing algorithm based on periodic diagram to obtain the first... The fuzzy function for the next iteration is calculated as follows:

[0090]

[0091] in To The corresponding signal matrix.

[0092] 9. Through the above operations, the strongest moving target echo will be removed. Return to step 4 and repeat the above steps until the maximum value of the absolute value of the fuzzy function is less than the termination threshold. The final output signal can be expressed as:

[0093]

[0094] The approximate equality sign is because it ignores echo signals with amplitudes below the termination threshold, i.e., it assumes that the label is... The target echo power is very low and has no impact on the demodulation of the uplink signal.

[0095] 10. Demodulate the uplink communication signal of the final output signal to obtain the communication information transmitted by the uplink user.

[0096] In the embodiments of this application, the interference suppression performance of the moving target echo interference canceller is defined as follows:

[0097]

[0098] in This represents the average residual echo power output by the moving target echo interference canceller. This represents the average echo power input to the moving target echo interference canceller. This represents the average noise power at the moving target echo interference canceller. This indicates the interference-to-noise ratio (INR) of the input moving target echo interference canceller echo. It represents the ratio of the residual echo power to the average power of the input echo.

[0099] Note that G is negative. The smaller the G value, the more thoroughly the moving target echo is suppressed, which means the moving target echo interference suppressor has better performance. Additionally, if INR... E When r = 0, G reaches a minimum value, indicating that the moving target echo interference canceller has reached the current INR.E Maximum suppression performance.

[0100] In the embodiments of this application, the baseband processing scheme can also be extended to utilize multiple antennas and applied to a beamforming integrated sensing system. When the target, static self-interference reflector, and uplink communication user are located in the same beam, this scheme can suppress static self-interference signals within the beam, sense moving targets within the beam, and demodulate uplink communication signals.

[0101] In the embodiments of this application, the actual system architecture constructed according to this application is as follows: Figure 1 As shown, a single-antenna full-duplex OFDM integrated sensing receiver receives uplink communication signals, moving target echoes, and static self-interference signals. Frequency-domain differential interference suppression is applied to the static self-interference, outputting a sum of the moving target echo and the uplink communication signal. OFDM radar processing is then applied to this sum to sense the distance and velocity information of the moving target. Subsequently, the proposed moving target echo interference canceller is used to suppress the moving target echo, extracting the uplink communication signal. Finally, the uplink communication information is demodulated. The performance of the proposed full-duplex communication and sensing integrated system is simulated and verified using MATLAB. The simulation parameters are set as follows:

[0102]

[0103] Figure 4 The power spectral density (PSD) of the proposed full-duplex integrated inductive receiver was simulated at different interference suppression stages, and the signal constellation diagram for each stage was plotted. In the figure, the static self-interference interference (SINOR) is 35 dB, the input echo SINOR is 12.45 dB, the uplink communication signal in-band signal-to-noise ratio (SNR) is 12 dB, and the data symbol modulation scheme is QPSK (Quadrature Phase Shift Keying). Figure 4 It can be seen that the proposed receiver processing flow can effectively perform static self-interference suppression and moving target echo suppression, with the residual echo signal close to the noise floor, and the expected signal output from the moving target echo suppression is significantly higher than the noise floor. Furthermore, the constellation diagram also shows that the proposed full-duplex integrated inductive receiver processing can obtain a good uplink communication signal QPSK constellation diagram, and can correctly demodulate the signal.

[0104] Figure 5The sensing performance of the full-duplex integrated sensing system proposed in this invention was simulated. The horizontal axis represents the moving target echo signal-to-noise ratio (ESNR), and the vertical axis represents the detection probability. It can be seen that the more OFDM symbols there are, the lower the ESNR required to achieve a completely correct detection probability, resulting in better sensing performance. Furthermore, the figure compares the OFDM detection probability with and without uplink communication signals. It is evident from the figure that the uplink communication signal affects the detection performance of the OFDM radar; with the same number of OFDM symbols, the radar requires a higher ESNR to achieve a correct detection probability.

[0105] Figure 6 The moving target echo interference suppression method proposed in this invention was simulated to demonstrate the relationship between interference suppression performance and input echo interference-to-noise ratio (IRR) under different values ​​of r. Note that the curve with r=0 in the figure represents the limiting suppression performance of the moving target echo interference canceller at the current input IRR. As can be seen from the figure, the interference suppression performance continuously improves with increasing input IRR. Furthermore, for the same input IRR, the smaller r is, the better the interference suppression performance.

[0106] Figure 7 The performance of the proposed full-duplex inductive integrated system in demodulating uplink communication signals was simulated after suppressing static self-interference and moving target echo interference. In the figure, the horizontal axis represents the ratio of bit energy to noise power spectral density, and the vertical axis represents the bit error rate (BER). The simulated communication channel is an AWGN (Additive White Gaussian Noise) channel, and the data symbols are also modulated using QPSK. Furthermore, the dashed line in the figure represents the theoretical limit of QPSK modulation in an AWGN channel. It can be seen that the more OFDM symbols there are, the better the uplink communication performance. When N... s When the value is 256, the uplink communication performance is close to the theoretical value.

[0107] The above description represents preferred embodiments of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technical or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A method for suppressing moving target echo interference in a full-duplex inductive integrated system, characterized in that: The full-duplex sensing integrated system includes a single-antenna full-duplex OFDM sensing integrated transmitter, a single-antenna full-duplex OFDM sensing integrated receiver, downlink users, static objects, sensing targets, and uplink users. The full-duplex OFDM inductive integrated transmitter is used to transmit continuous OFDM signals, which serve as downlink ISAC signals and have the following function: (1) As a downlink communication signal, it undertakes the downlink communication function from the base station to the downlink user; (2) As a radar detection signal, it transmits signals to dynamically sensed targets; The signals received by the full-duplex OFDM integrated inductive receiver include: (1) Uplink communication signals transmitted by uplink users; (2) The echo of a moving target reflected by a dynamically sensed target; (3) Direct self-interference signal leaked from OFDM full-duplex inductive integrated transmitter; (4) Multipath self-interference echoes reflected by static objects in the environment; Among them, (3) and (4) are static self-interference signals; The method includes the following steps: S1. The full-duplex OFDM inductive integrated transmitter transmits OFDM continuous signals for target perception and downlink communication, and the uplink user transmits OFDM continuous signals for uplink communication. The full-duplex OFDM inductive integrated receiver receives the signals and performs front-end processing to suppress static self-interference signals. S2. Perform OFDM radar processing based on periodograms on the signal after self-interference suppression to obtain the initial ambiguity function Λ. (0) (τ,f D ), and extract the delay / Doppler information of the target echo; S3. Number the targets according to their echo power and set a termination threshold; Initialize the number of iterations Number of iterations Corresponding fuzzy function That is, the initial fuzzy function Λ (0) (τ,f D ); S4. Relate the termination threshold Γ to the iteration count. fuzzy function The maximum absolute value is compared; if the maximum value is greater than the termination threshold, the next step is executed; otherwise, the loop is terminated and a signal is output. S5. Estimating the first The time delay and Doppler shift of each target are used to perform the first... Reconstruction of the target echo and acquisition of the first target echo The next iteration signal; S6. To Sub-iteration signal Perform OFDM radar processing based on periodic diagrams to obtain the first... The fuzzy function of the next iteration; S7. Order Soon The value is updated to Repeat steps S4 to S6 until the maximum value of the absolute value of the fuzzy function is less than the termination threshold, and obtain the final output signal.

2. The method for suppressing moving target echo interference in a full-duplex inductive integrated system according to claim 1, characterized in that: Step S1 includes: S101. The full-duplex OFDM inductive transmitter transmits continuous OFDM signals for target sensing and downlink communication via a single transmitting antenna; The full-duplex OFDM inductive transmitter first modulates, converts, and adds a cyclic prefix to the transmitted bits before performing digital-to-analog conversion. Then, it performs up-conversion to generate an OFDM continuous signal, which is then transmitted through a single antenna. S102. The uplink user transmits an OFDM continuous signal for uplink communication; S103. Signal reception is performed at the OFDM integrated inductive receiver; S104. The signal is received by a single antenna of the OFDM inductive receiver. After front-end processing, the received signal is converted into a frequency domain signal. The frequency domain signal of the m-th OFDM symbol and the n-th subcarrier is represented as R. n,m ,in, n = 0, 1, ..., N c -1, m = 0, 1, ..., N s -1, N c With N s These represent the number of subcarriers in an OFDM symbol and the number of OFDM symbols, respectively; the front-end processing includes radio frequency interference cancellation, down-conversion, analog-to-digital conversion, cyclic prefix removal, and time-frequency conversion; S105. Static self-interference suppression is performed on the frequency domain signal. Static self-interference suppression employs a frequency domain differential interference suppression module. This module utilizes the time-invariant characteristics of static self-interference to suppress frequency domain signal R. n,m Differential operations are performed on subcarriers at the same position along different OFDM symbols to obtain a frequency domain differential sequence; then, a smoothing operation is performed on the differential sequence to suppress static self-interference signals, and the desired uplink communication signal and the sum of the moving target echo signal are output.

3. The method for suppressing moving target echo interference in a full-duplex inductive integrated system according to claim 2, characterized in that: Step S2 includes: S201. Pair signal Directly perform OFDM radar processing based on periodograms to obtain the initial ambiguity function Λ. (0) (τ,f D The specific handling is as follows: S2011. Regarding Corresponding signal matrix Element-wise division is performed to remove the data modulation symbol matrix X of the downlink communication signal. Then, a two-dimensional Fourier transform is performed on the signal with the data symbols removed to obtain the complex periodogram function. Where . / represents element-wise division between matrices. Representing the normalized discrete Fourier transform matrix: The element in the (k+1)th row and (i+1)th column is The element in the (k′+1)th row and (i′+1)th column is S2012. For complex periodogram functions By performing mapping, we obtain the initial fuzzy function: This represents the mapping from a complex periodogram function to a fuzzy function, that is, mapping the grid coordinates representing time delay and Doppler to specific numerical time delay and Doppler coordinates: Among them, complex periodogram functions For N c Line N s The column matrix, specifically the mapping process, is as follows: (1) Let the time-delay grid coordinates be represented as n′=0,1,...,N c -1, Doppler grid coordinates are represented as m′=0,1,...,N s -1; (2) For any coordinate (n′, m′), the following is performed: Mapping: Where Δτ represents the delay resolution, B represents the sensing signal bandwidth; Δf D T represents Doppler resolution. s Indicates the duration of an OFDM symbol; Will The element in the (n′+1)th row and the (m′+1)th column is used as the coordinate (n′, m′) to map τ′,(f D The element corresponding to )′ in the initial fuzzy matrix is ​​denoted as Λ. (0) (τ′,(f D )′); (3) In n′=0,1,...,N c -1,m′=0,1,...,N s -1, iterate through each coordinate and repeat (2) for each coordinate, thus obtaining τ′,(f) corresponding to each (n′,m′). D )′ and Λ (0) (τ′,(f D )′), thus forming Λ (0) (τ,f D ); S202. Detect moving targets and extract the delay / Doppler information of the moving target echo as sensing information: Initial fuzzy function Λ (0) (τ,f D (also N) c Line N s A matrix of columns; For each coordinate (τ′, (f) D )′), and its corresponding element Λ in the initial fuzzy function matrix. (0) (τ′,(f D The modulus of (τ′) is compared with a preset target detection threshold. If the modulus is greater than the target detection threshold, then (τ′,(f) is considered to be true. D There is a moving target at ()′). Suppose a total of P moving targets are detected, and the time delay / Doppler frequency shift of the p-th target is expressed as τ. p ,(f D ) p .

4. The method for suppressing moving target echo interference in a full-duplex integrated sensing system according to claim 1, characterized in that: Step S3 includes: S301. Assume there are P sensing targets, and the targets are numbered from largest to smallest according to their echo power: 0, 1, 2, ..., P-1; S302. Set the termination threshold, defined as: Where, N c N represents the number of subcarriers contained in an OFDM symbol. s Indicates the number of OFDM symbols. SNR represents the receiver noise average power. thre Defined as the target echo signal-to-noise ratio threshold to be suppressed; defined as the number of targets with echo amplitude greater than the threshold Γ. have 5. The method for suppressing moving target echo interference in a full-duplex inductive integrated system according to claim 3, characterized in that: Step S5 includes: S501. Through the first The fuzzy function of the next iteration The maximum absolute value, estimate the th The time delay and Doppler shift of each target are expressed as follows: S502. The first The target echo reconstruction is as follows in This represents the estimated channel coefficient corresponding to the target echo. X represents the phase rotation caused by time delay and Doppler shift on the nth subcarrier of the m-th OFDM symbol. n,m This represents the data modulator for the downlink communication signal at the m-th OFDM symbol and the n-th subcarrier. S503. From the... Sub-iteration signal Subtract the first The reconstructed moving target echo signal is obtained. Next iteration signal:

6. The method for suppressing moving target echo interference in a full-duplex integrated sensing system according to claim 5, characterized in that: Step S502 includes: A1. Using the first Delay estimates for each target Compared with Doppler estimates The reconstructed portion of the target's echo signal is shown below: A2. Depend on Signal and the Sub-iteration signal The cross-correlation is obtained as follows: in 7. The method for suppressing moving target echo interference in a full-duplex integrated sensing system according to claim 6, characterized in that: Step S6 includes: right Sub-iteration signal OFDM radar processing is performed to obtain the first... The fuzzy function for the next iteration is calculated as follows: in for The corresponding signal matrix.

8. The method for suppressing moving target echo interference in a full-duplex inductive integrated system according to claim 7, characterized in that: In step S7, when the maximum value of the absolute value of the fuzzy function is less than the termination threshold, the final output signal is represented as follows: The approximate equality sign is because it ignores the power of echo signals with amplitudes below the termination threshold, i.e., it assumes that the label is... The target echo power is very low and has no impact on the demodulation of the uplink signal.

9. The method for suppressing moving target echo interference in a full-duplex inductive integrated system according to claim 1, characterized in that: The method further includes: The final output signal is demodulated to obtain the communication information transmitted by the uplink user.

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