Integrated sensing and backscatter communication method and device based on backscatter

Abstract

The invention discloses an integrated sensing and backscatter communication method and device based on backscatter, and relates to the technical field of wireless communication, and the method comprises the steps: receiving an open-circuit pilot frequency receiving voltage and a short-circuit pilot frequency receiving voltage generated by a receiving antenna based on a pilot frequency signal; determining a tag antenna mode pilot frequency voltage component and a clutter tag structure combined pilot frequency voltage component, and correspondingly determining a tag antenna mode reflection coefficient and a clutter tag structure combined reflection coefficient based on the tag antenna mode pilot frequency voltage component and the clutter tag structure combined pilot frequency voltage component by adopting a compressed sensing algorithm; and transmitting a data signal to a receiving antenna through the tag by adopting binary phase shift keying, collecting a data receiving voltage, and completing signal demodulation by adopting the data receiving voltage, a tag antenna mode reflection coefficient and a combined reflection coefficient to obtain a bit mapping symbol of the data signal. The backscatter communication is realized through combination of backscatter and tag impedance modulation, and the backscatter communication performance is improved.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to an integrated sensing and backscattering communication method and device based on backscattering. Background Art

[0002] In the rapid development of the Internet of Things, backscatter communication has attracted widespread attention as a low-cost and efficient data transmission method. With the rise of the concept of Integrated Sensing and Communication (ISAC), it has become possible to share limited spectrum and expensive hardware resources between communication and sensing systems. This integration can not only save a lot of costs, but also promote powerful communication and high-precision sensing capabilities. In this case, academia and industry have begun to study the integration of positioning technology into backscatter communication systems to achieve precise sensing.

[0003] In the prior art, methods based on signal strength and phase difference ranging are usually used to locate the passive tag antenna in the backscatter system. However, there is a problem of multipath effect caused by clutter scatterers, which affects the positioning accuracy and leads to poor backscatter communication performance. Summary of the invention

[0004] The present invention provides an integrated sensing and backscattering communication method and device based on backscattering, which solves the technical problem that in the prior art, when positioning a passive tag antenna in a backscattering system, there is a multipath effect caused by clutter scatterers, thereby affecting the positioning accuracy and causing poor backscattering communication performance.

[0005] A first aspect of the present invention provides an integrated sensing and backscattering communication method based on backscattering, comprising:

[0006] After transmitting the pilot signal to the tag through the transmitting antenna, modulating the tag to be in an open circuit state to generate an open circuit pilot signal of the pilot signal and in a short circuit state to generate a short circuit pilot signal of the pilot signal, and backscattering the open circuit pilot signal and the short circuit pilot signal to the receiving antenna;

[0007] Determine a tag antenna mode pilot voltage component and a clutter tag structure combined pilot voltage component according to an open-circuit pilot reception voltage generated by the receiving antenna based on the open-circuit pilot signal and a short-circuit pilot reception voltage generated by the short-circuit pilot signal;

[0008] A compressed sensing algorithm is used to construct an underdetermined linear equation group based on the pilot voltage component of the tag antenna pattern and the pilot voltage component of the clutter tag structure combination, and the underdetermined linear equation group is optimized and solved to correspondingly determine the reflection coefficient of the tag antenna pattern and the reflection coefficient of the clutter tag structure combination;

[0009] When the transmitting antenna activates the tag, a data signal is transmitted to the receiving antenna by using binary phase shift keying through the tag, and a data receiving voltage of the receiving antenna is collected;

[0010] The tag antenna pattern reflection coefficient and the clutter tag structure combination reflection coefficient are respectively used to correspondingly determine the tag antenna pattern data voltage component and the clutter tag structure combination data voltage component of the data signal;

[0011] The data receiving voltage, the clutter tag structure combined data voltage component and the tag antenna mode data voltage component are combined to perform signal demodulation to obtain a bit mapping symbol of the data signal.

[0012] Optionally, determining the tag antenna mode pilot voltage component and the clutter tag structure combined pilot voltage component according to the open-circuit pilot reception voltage generated by the receiving antenna based on the open-circuit pilot signal and the short-circuit pilot reception voltage generated by the short-circuit pilot signal includes:

[0013] collecting an open-circuit pilot reception voltage generated by the receiving antenna based on the open-circuit pilot signal and a short-circuit pilot reception voltage generated based on the short-circuit pilot signal;

[0014] Taking half the difference between the open circuit pilot reception voltage and the short circuit pilot reception voltage to obtain a tag antenna mode pilot voltage component;

[0015] A mean operation is performed on the open-circuit pilot reception voltage and the short-circuit pilot reception voltage to obtain a clutter label structure combined pilot voltage component.

[0016] Optionally, constructing an underdetermined linear equation group based on the tag antenna pattern voltage component and the clutter tag structure combination voltage component respectively through a compressed sensing algorithm and performing optimization solutions to correspondingly determine the tag antenna pattern reflection coefficient and the clutter tag structure combination reflection coefficient, includes:

[0017] Constructing a first underdetermined linear equation group about the clutter tag structure combination reflection coefficient based on the clutter tag structure combination voltage component by a compressed sensing algorithm;

[0018] A two-step iterative shrinkage threshold algorithm is used to optimize and solve the first underdetermined linear equations to determine the reflection coefficient of the clutter label structure combination;

[0019] Constructing a second underdetermined linear equation group about the tag antenna pattern reflection coefficient based on the tag antenna pattern voltage component by a compressed sensing algorithm;

[0020] A two-step iterative shrinkage threshold algorithm is used to optimize and solve the second underdetermined linear equations to determine the tag antenna pattern reflection coefficient.

[0021] Optionally, the combining the data receiving voltage, the clutter tag structure combined data voltage component and the tag antenna mode data voltage component to perform signal demodulation to obtain a bit mapping symbol of the data signal includes:

[0022] Subtracting the data receiving voltage from the clutter tag structure combined data voltage component to obtain a receiving signal of the receiving antenna;

[0023] The received signal and the tag antenna pattern data voltage component are input into a preset reverse communication model and demodulated through maximum ratio combining to obtain a bit mapping symbol of the data signal.

[0024] Optionally, the reverse communication model is specifically:

[0025] ;

[0026] In the formula, For the bit-mapped symbols of the received signal, is the voltage component vector of the tag antenna pattern, For the bitmap symbols, For the The noise of the bit-mapped symbols.

[0027] Optionally, the process of determining the voltage component of the tag antenna mode data is specifically as follows:

[0028] ;

[0029] The process of determining the voltage component of the clutter tag structure combined data is specifically as follows:

[0030] ;

[0031] In the formula, For the transmitting antennas, For the A receiving antenna, is the voltage component of the tag antenna mode, is an imaginary number, is the angular frequency, is the vacuum permeability, is the standardization factor, is the region of interest where the tags and clutter scatterers are located, For the The field radiated by a receiving antenna operating in transmit mode with unit excitation, For the The transmitting antennas are located at The incident field generated at is the tag antenna pattern reflection coefficient, is the area of ​​each spatial pixel in the domain of interest, is the combined voltage component of the clutter tag structure, Combined reflection coefficients for clutter tag structures.

[0032] A second aspect of the present invention provides an integrated sensing and backscattering communication device based on backscattering, comprising:

[0033] A pilot modulation module, configured to, after transmitting a pilot signal to a tag through a transmitting antenna, modulate an open-circuit pilot signal in which the tag is in an open circuit state to generate the pilot signal and a short-circuit pilot signal in which the tag is in a short circuit state to generate the pilot signal, and backscatter the open-circuit pilot signal and the short-circuit pilot signal to a receiving antenna;

[0034] A pilot voltage determination module, configured to determine a tag antenna mode pilot voltage component and a clutter tag structure combined pilot voltage component according to an open-circuit pilot reception voltage generated by the receiving antenna based on the open-circuit pilot signal and a short-circuit pilot reception voltage generated by the short-circuit pilot signal;

[0035] A reflection coefficient determination module is used to construct an underdetermined linear equation group based on the pilot voltage component of the tag antenna pattern and the pilot voltage component of the clutter tag structure combination by using a compressed sensing algorithm and optimize the solution to correspondingly determine the reflection coefficient of the tag antenna pattern and the reflection coefficient of the clutter tag structure combination;

[0036] A signal transmission and acquisition module, used for transmitting a data signal to the receiving antenna by using binary phase shift keying through the tag when the transmitting antenna activates the tag, and acquiring a data receiving voltage of the receiving antenna;

[0037] A signal voltage calculation module, used to respectively use the tag antenna pattern reflection coefficient and the clutter tag structure combination reflection coefficient to correspondingly determine the tag antenna pattern data voltage component and the clutter tag structure combination data voltage component of the data signal;

[0038] The signal demodulation module is used to perform signal demodulation on the data receiving voltage, the clutter tag structure combined data voltage component and the tag antenna mode data voltage component to obtain a bit mapping symbol of the data signal.

[0039] A third aspect of the present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the integrated sensing and backscattering communication method based on backscattering as described in any one of the above items.

[0040] A fourth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed, implements the integrated sensing and backscattering communication method based on backscattering as described in any one of the above items.

[0041] A fifth aspect of the present invention provides a computer program product, comprising a computer program / instruction, which, when executed by a processor, implements the integrated sensing and backscattering communication method based on backscattering as described in any one of the above items.

[0042] It can be seen from the above technical solutions that the present invention has the following advantages:

[0043] The above scheme of the present invention provides an integrated sensing and backscattering communication method based on backscattering, including: after transmitting a pilot signal to a tag through a transmitting antenna, modulating the tag to be in an open circuit state and a short circuit state respectively and correspondingly backscattering the pilot signal to a receiving antenna; determining the tag antenna mode pilot voltage component and the combined pilot voltage component of the clutter scatterer and the tag structure mode according to the pilot reception voltage generated by the receiving antenna based on each pilot signal; using a compressed sensing algorithm to construct an underdetermined linear equation group based on the tag antenna mode pilot voltage component and the combined pilot voltage component and optimize and solve them, and correspondingly determine the tag antenna mode reflection coefficient and the combined reflection coefficient; when the transmitting antenna activates the tag, the data signal is transmitted to the receiving antenna through the tag using binary phase shift keying, and the data reception voltage of the receiving antenna is correspondingly collected; using the tag antenna mode reflection coefficient and the combined reflection coefficient respectively, correspondingly determining the tag antenna mode data voltage component and the clutter tag structure combined data voltage component associated with the data signal; jointly demodulating the data reception voltage, the clutter tag structure combined data voltage component and the tag antenna mode data voltage component to obtain a bit mapping symbol of the data signal. Based on the above scheme, by modulating the tags in open and short circuit states, the tag antenna mode pilot voltage component and the clutter tag structure combined pilot voltage component are extracted respectively, and the inverse scattering and compressed sensing algorithms are applied to perceive the tag and the clutter scatterer based on the clutter tag structure combined pilot voltage component, and the tag antenna mode pilot voltage component is used for tag identification. The inverse scattering-based imaging method is combined with the impedance of the modulated tag to realize backscattering communication. It is possible to realize simultaneous positioning, identification and backscattering communication of tags in a cluttered environment, thereby improving the backscattering communication performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0045] Figure 1 A flowchart of a method for integrated sensing and backscattering communication based on backscattering provided by an embodiment of the present invention;

[0046] Figure 2 A schematic diagram of the structure of an integrated sensing and backscattering communication system provided by an embodiment of the present invention;

[0047] Figure 3 A schematic diagram of the sensing and recognition results of three tags and a closed clutter scatterer provided in an embodiment of the present invention;

[0048] Figure 4 The scattering response results at the receiving antenna of the integrated sensing and backscattering communication system provided by the embodiment of the present invention in the scenario of a single copper dipole antenna and a single copper clutter scatterer;

[0049] Figure 5 The BER performance of bit-mapped symbols under different SNRs in Monte Carlo simulation of the integrated sensing and backscattering communication system provided in the embodiment of the present invention;

[0050] Figure 6 A structural block diagram of an integrated sensing and backscattering communication device based on backscattering provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0051] The embodiment of the present invention provides an integrated sensing and backscattering communication method and device based on backscattering, which is used to solve the technical problem that in the prior art, when positioning the passive tag antenna in the backscattering system, there is a multipath effect problem caused by clutter scatterers, thereby affecting the positioning accuracy and causing poor backscattering communication performance.

[0052] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] See also Figure 1 , Figure 1 A flowchart of the steps of an integrated sensing and backscattering communication method based on backscattering is provided in an embodiment of the present invention.

[0054] The present invention provides an integrated sensing and backscattering communication method based on backscattering, comprising:

[0055] Step 101, after transmitting a pilot signal to a tag through a transmitting antenna, modulate the tag to be in an open circuit state to generate an open circuit pilot signal and in a short circuit state to generate a short circuit pilot signal, and backscatter the open circuit pilot signal and the short circuit pilot signal to a receiving antenna.

[0056] It should be noted that this embodiment is applied to an integrated sensing and backscattering communication system, such as Figure 2 As shown, the system is equipped with The transmit antenna array (Receive Array) consists of a transmit antenna and The receiving antenna array consists of a receiving antenna (Transmit Array). The transmitting antenna array and the receiving antenna array are placed outside the domain of interest (DoI). In the specific implementation, , , when When transmitting from a transmitting antenna, This allows for a total of Measurement;

[0057] To simplify the explanation, the considered domain of interest DOI is represented as a two-dimensional (2D) plane section. The area is denoted as D, and DOI is further divided into Pixels, where , Respectively represent the number of spatial pixels in the x-y plane, is the unit length in the x-axis direction, is the unit length in the y-axis direction, and the area of ​​each spatial pixel is ; There are a total of The spatial pixels of ; In this embodiment, the DOI includes a clutter scatterer (ClutterScatterer) with a constant reflection coefficient and a tag (Tag) that can modulate the backscatter communication reflection coefficient, and the number of transmitting antennas, receiving antennas, clutter scatterers and tags, each structure can be single or multiple;

[0058] Assuming that the DOI can be approximated by a uniform grid of point scatterers with reflectance values, we can write the entire field as:

[0059] (1)

[0060] In the formula, For the The transmitting antennas are located at The total electric field generated at For the The transmitting antennas are located at The incident field generated at For the The transmitting antennas are located at The scattered field generated at

[0061] The scattered field at any point in DOI can be further expressed as:

[0062] (2)

[0063] In the formula, For location The reflection coefficients of clutter scatterers and tags at ;

[0064] Generally, tags are composed of antennas and loads. Modulating the tag scattering field is achieved by controlling the mismatch between the antenna impedance and the load impedance. For example, the reflection coefficient is defined as:

[0065] (3)

[0066] In the formula, is the label reflection coefficient, is the antenna impedance, is the load impedance, is the complex conjugate operation; when hour, ; When the When the transmitting antenna transmits, the scattered field of the tag with load impedance It can be broken down into:

[0067] (4)

[0068] In the formula, is the scattered field of the tag structure mode, is the scattered field of the tag antenna pattern, is the scattering current with conjugate matching caused by the incident field of the transmitting antenna at the tag antenna, is the tag antenna radiation field of unit excitation; it can be understood that the tag scattering field includes the scattering field of the structural mode and the antenna mode. The scattering field of the tag structural mode is not affected by the load impedance. It is determined by physical properties such as shape, size, position and composition, while the scattering field of the tag antenna mode depends on the load conditions and can be modulated to facilitate data transmission in backscatter communication, which also makes it possible to identify tags from clutter scatterers; the scattering field of the clutter scatterer is expressed as , then the scattered field in equation (2) can be rewritten as:

[0069] (5)

[0070] In addition, the scattering field of the clutter scatterer and the scattering field of the tag structure mode can be combined into a constant clutter tag structure combined scattering field , and has nothing to do with the load impedance of the tag, the expression is as follows:

[0071] (6)

[0072] Combining equations (2), (5) and (6), we can This breaks down into:

[0073] (7)

[0074] In the formula, is the clutter tag structure combined reflection coefficient, is the tag antenna pattern reflection coefficient; further:

[0075] (8)

[0076] (9)

[0077] Therefore, in this embodiment, the clutter tag structure combined reflection coefficient can be used to sense the location of clutter scatterers and tags, and use the tag antenna pattern reflection coefficient to identify tags from clutter scatterers;

[0078] By changing the load impedance , the tag can present different reflection coefficients through the antenna mode. This embodiment takes the open circuit and short circuit load impedance, namely Binary phase shift keying (BPSK), as an example to verify the above concept. For the load impedance in the open circuit state, , for the load impedance in the open circuit state, , then based on formula (5), the scattered field Respectively expressed as:

[0079] (10)

[0080] (11)

[0081] Based on the conversion of equations (10) and (11), the scattering field of the clutter tag structure combination and the scattering field of the tag antenna mode are obtained as follows:

[0082] (12)

[0083] (13)

[0084] By checking equations (12)-(13), we show that we can extract the combined scattered field of the clutter tag structure from the scattered field with open and short-circuit load impedances. and the scattered field of the tag antenna pattern ;

[0085] In practical applications, the scattered fields in equations (2) and (5) are directly measured. Therefore, a receiving antenna is usually used to sense the scattered field and convert it into a measurable received voltage. The scattered field at can be expressed as:

[0086] (14)

[0087] In the formula, for Location, is an imaginary number, is the angular frequency, is the vacuum permeability, is the Green function, which is written as the Hankel function in a two-dimensional scene ; The Green's function in equation (14) is replaced by the electric field radiated by the receiving antenna when it works in the unit excitation transmission mode, so that the measurable received voltage can be related to the scattered field:

[0088] (15)

[0089] In the formula, For the The receiving antenna is The received voltage generated by the scattered field generated by the transmitting antenna is For the The field radiated by a receiving antenna operating in transmit mode with unit excitation, is the standardization factor;

[0090] Since there are two unknowns in equation (15): and , it cannot be inferred from the received voltage measured at the receiving antenna , at this time, the linear Born approximation is used to solve the problem, and the total electric field Approximately the incident field , thus the inverse scattering problem (15) can be simplified to:

[0091] (16)

[0092] Based on formula (7), the received voltage can be decomposed into:

[0093] (17)

[0094] In the formula, is the combined voltage component of the clutter tag structure, is the voltage component of the tag antenna mode; combined with formula (16), we can get:

[0095] (18)

[0096] (19)

[0097] Therefore, by giving and It can be estimated that and , which is then used to sense the location of clutter scatterers and tags, and identify tags from clutter scatterers.

[0098] In the specific implementation, a pilot signal is first transmitted to the tag through the transmitting antenna to activate the tag. The pilot signal is usually a known reference signal, which is often used in processes such as channel estimation, synchronization and frequency correction. At this time, the modulated tag is in an open circuit state and a short circuit state respectively. In the open circuit state, an open circuit pilot signal is modulated to generate a short circuit pilot signal, and in the short circuit state, a short circuit pilot signal is modulated to generate a short circuit pilot signal, and both are backscattered to the receiving antenna to generate a corresponding receiving voltage at the receiving antenna.

[0099] Step 102: Determine a tag antenna mode pilot voltage component and a clutter tag structure combined pilot voltage component according to an open circuit pilot reception voltage generated by a receiving antenna based on an open circuit pilot signal and a short circuit pilot reception voltage generated by a short circuit pilot signal.

[0100] Step 102 includes the following sub-steps:

[0101] S11, collecting receiving antenna based on open circuit pilot signal The generated open circuit pilot reception voltage and the short circuit pilot signal based on The generated short-circuit pilot receiving voltage;

[0102] S12, taking half the difference between the open-circuit pilot receiving voltage and the short-circuit pilot receiving voltage to obtain the tag antenna mode pilot voltage component;

[0103] S13, performing mean operation on the open-circuit pilot reception voltage and the short-circuit pilot reception voltage to obtain a clutter label structure combined pilot voltage component.

[0104] It should be noted that, based on formula (17), the received voltage corresponding to the open-circuit pilot signal and the short-circuit pilot signal is:

[0105] (20)

[0106] (twenty one)

[0107] Based on the transformation of formula (20) and formula (21), we can get:

[0108] (twenty two)

[0109] (twenty three)

[0110] In the formula, is the open circuit pilot receiving voltage, is the short-circuit pilot receiving voltage; transmit antennas and A receiving antenna, and In , , and can be combined into a vector, so it can be recorded as the clutter label structure combined voltage component vector and label antenna pattern voltage component vector ,in, , .

[0111] Step 103: Use a compressed sensing algorithm to construct an underdetermined linear equation system based on the tag antenna pattern pilot voltage component and the clutter tag structure combination pilot voltage component and optimize the solution to correspondingly determine the tag antenna pattern reflection coefficient and the clutter tag structure combination reflection coefficient.

[0112] Step 103 includes the following sub-steps:

[0113] S21. Constructing a first underdetermined linear equation group about the clutter tag structure combination reflection coefficient based on the clutter tag structure combination voltage component by using a compressed sensing algorithm.

[0114] S22. Using a two-step iterative shrinkage threshold algorithm to optimize and solve the first underdetermined linear equations, and determine the reflection coefficient of the clutter label structure combination.

[0115] It should be noted that, firstly, the clutter tag structure combined voltage component is considered to sense the position of the clutter scatterer and the tag. From equation (18), it can be obtained:

[0116] (twenty four)

[0117] in, can be split into different directions, namely , Yes The measurement matrix of the arrangement, where , is the number of columns or rows of the matrix. The transmitting antenna incident vector Indicates The incident field generated by the transmitting antenna within the DOI, the incident vector of the receiving antenna Indicates The incident field generated by the receiving antennas within the DOI;

[0118] The measured value obtained from equation (24) Retrieve clutter label structure combined reflection coefficient , a direct approach is to find the inverse measurement matrix , so that However, because the number of independent observations is usually less than the number of unknowns N, the measurement matrix H is usually irreversible. For sparse objects or scatterers, compressed sensing methods (CS algorithms) can be used to solve the underdetermined problem to achieve image reconstruction. Specifically, the problem can be expressed as the first underdetermined linear equations of the reflection coefficient of the clutter-label structure combination of the clutter scatterer and the label structure pattern:

[0119] (25)

[0120] In the formula, is the L1 norm; the two-step iterative shrinkagethresholding algorithm (TwIST) is used to optimize the solution of the first underdetermined linear equations, and the estimated reflection coefficient is iteratively updated by applying shrinkage and threshold operations to recover the reflection coefficient of the sparse clutter label structure combination ,because represents the reflection coefficient of the clutter scatterer and tag structure mode, so we can recover The position of the clutter scatterer and the tag can be sensed in the image, but it is not enough to identify the tag from the clutter scatterer. Therefore, in order to identify the tag, it is necessary to restore .

[0121] S23. Construct a second underdetermined linear equation group about the tag antenna pattern reflection coefficient based on the tag antenna pattern voltage component by using a compressed sensing algorithm.

[0122] S24. Use a two-step iterative shrinkage threshold algorithm to optimize and solve the second underdetermined linear equation group to determine the tag antenna pattern reflection coefficient.

[0123] It should be noted that the use of the tag antenna pattern voltage component to identify the tag from the clutter scatterer is different from the recovery The similar process of is shown in equations (26) and (27). The compressed sensing algorithm and the two-step iterative shrinkage threshold algorithm are used to solve , thereby identifying the tag from the clutter scatterers.

[0124] (26)

[0125] (27)

[0126] To further illustrate the tag recognition effect of steps 101-103 of this embodiment in actual application, take three tags and a single copper clutter scatterer of the same size as an example, and the recognition and reconstruction results are as follows: Figure 3 As shown, the white curve represents the ground truth boundary of the clutter scatterer and the gray curve represents the ground truth boundary of the label:

[0127] exist Figure 3 In (a)-(h), the peak signal-to-noise ratio (PSNR) and structural similarity (SSIM) values ​​reconstructed based on the reflection coefficient are: (a) (PSNR=22.70dB, SSIM=0.97), (b) (PSNR=27.70dB, SSIM=0.99), (c) (PSNR=27.76dB, SSIM=0.99), (d) (PSNR=31.84dB, SSIM=0.99), (e) (PSNR=28.10dB, SSIM=0.98), (f) (PSNR=28.09dB, SSIM=0.99), (g) (PSNR=27.49dB, SSIM=0.98) and (h) PSNR=25.37dB, SSIM=0.97;

[0128] like Figure 3 As shown in (a), three tags and a clutter scatterer can be accurately reconstructed in the sensing stage; in the recognition stage, Figure 3As shown in (b)-(d), each tag can be identified individually; in addition, Figure 3 As shown in (e)-(g), any two labels can be well reconstructed and recognized; finally, as Figure 3 As shown in (h), all three tags can be identified and distinguished simultaneously;

[0129] These results demonstrate that various combinations of multiple tags can be accurately reconstructed in an integrated sensing and backscatter communication system using the approach described above.

[0130] It is understandable that the inverse scattering technology reconstructs the spatial distribution of physical properties by inverting measured scattering data. However, inverse scattering problems (ISPs) are widely considered to be ill-conditioned and nonlinear. In the prior art, linear methods such as linear Born approximation (BA), Rytov approximation (RA), and extended Rytov approximation (xRA) provide powerful techniques for processing noise and errors in inverse scattering, simplify calculations, and promote imaging and positioning tasks. However, these inverse scattering techniques usually provide high-fidelity imaging and precise positioning for clutter scatterers with time-invariant reflectivity. This embodiment cleverly applies the inverse scattering technology to scatterers with time-varying reflectivity, so that the inverse scattering technology can be used not only to perceive tags and clutter scatterers in a cluttered environment, but also to accurately locate and identify individual or combined tags.

[0131] Step 104: When the transmitting antenna activates the tag, the tag transmits a data signal to the receiving antenna using binary phase shift keying in response to the activation signal, and collects the data receiving voltage of the receiving antenna.

[0132] It should be noted that after the tag sends a pilot signal for sensing and identification, backscatter communication can be performed. When the transmitting antenna transmits an activation signal to the tag, the tag can obtain energy from it to activate its circuit. The activation signal can be understood as a continuous wave carrier signal. Its main purpose is to provide energy for the passive tag and serve as a stable reference signal so that the tag can modulate it. The tag changes its impedance through binary phase shift keying (BPSK) according to the data to be transmitted to modulate it into a data signal reflected to the receiving antenna; specifically, the tag switches between open and short-circuit load impedances. The k-th bit mapping symbol for the tag transmission is represented as , for each bitmap symbol we can measure the data reception voltage at the receiving antenna for different transmitting antennas .

[0133] Step 105 : respectively using the tag antenna pattern reflection coefficient and the clutter tag structure combination reflection coefficient to correspondingly determine the tag antenna pattern data voltage component and the clutter tag structure combination data voltage component of the data signal.

[0134] It should be noted that according to equations (18) and (19), the field radiated by the receiving antenna when operating in the transmission mode of unit excitation is , and the incident field of the transmitting antenna associated with the data signal, that is, the incident field of the transmitting antenna when transmitting the activation signal, the tag antenna pattern reflection coefficient and the clutter tag structure combination reflection coefficient are used to calculate the corresponding tag antenna pattern data voltage component and the clutter tag structure combination data voltage component.

[0135] Step 106: Demodulate the data receiving voltage, the clutter tag structure combined data voltage component, and the tag antenna pattern data voltage component to obtain a bit mapping symbol of the data signal.

[0136] Step 106 includes the following sub-steps:

[0137] S31, performing a subtraction operation on the data receiving voltage and the clutter tag structure combined data voltage component to obtain a receiving signal of the receiving antenna;

[0138] S32, inputting the received signal and the tag antenna pattern data voltage component into a preset reverse communication model and demodulating them through maximum ratio combining to obtain a bit mapping symbol of the data signal.

[0139] It should be noted that we can measure the data receiving voltage Combined into a data receiving voltage vector, expressed as ,in , using formula (17), we can and Get in touch:

[0140] (28)

[0141] Next, by removing The combined voltage component vector of the clutter and tag structure patterns in To define the received signal ,Right now , and considering the noise Influence, construct the functional relationship between the received signal and the bit mapping symbol, and obtain the backscatter communication model as follows:

[0142] (29)

[0143] In the formula, For the bit-mapped symbols of the received signal, is the voltage component vector of the tag antenna pattern, For the bitmap symbols, For the The noise of bit-mapped symbols

[0144] Furthermore, the maximum ratio combining technique (MRC) algorithm, i.e. the optimal linear combiner, is used. Enhanced symbol detection to further improve communication performance, demodulation To get ,in:

[0145] (30)

[0146] In the formula, is the combination of received signals.

[0147] To further illustrate the scattering communication performance of this embodiment in practical applications, we consider a specific scenario, taking a single copper dipole antenna and a single copper clutter scatterer in the DOI as an example. The received total response receiving voltage V includes the tag's structural mode and clutter scattering as well as the tag's antenna mode. The magnitudes of the open-circuit and short-circuit conditions are as follows: Figure 4 As shown in (a), Figure 4 (b) is the amplitude distribution of the structure mode of clutter scattering and label extracted based on equation (22) , extract the amplitude distribution of the tag's antenna pattern in open and short circuit conditions like Figure 4 (c), while the amplitude of the antenna pattern in the open circuit and short circuit conditions is the same, as shown in Figure 4 As shown in (d), the phase difference between the open circuit and short circuit conditions always maintains a value of π or -π. Through BPSK modulation, this phase difference can be effectively used for data communication;

[0148] In addition to this analysis, we also evaluate the BER performance of the proposed backscatter communication through 105 Monte Carlo simulation experiments. The relationship between the uplink bit error rate BER performance and the signal-to-noise ratio SNR of the backscatter communication using MRC technology is shown in Figure 5 As shown, our simulation results are very consistent with the theoretical BER performance; the evaluation process of the uplink bit error rate includes:

[0149] (31)

[0150] In the formula, is the bit error rate, is the Q function (also known as the right tail function of the standard normal distribution), is the overall standard deviation.

[0151] In this embodiment, by modulating the tags in the open circuit and short circuit states, the tag antenna mode pilot voltage component and the clutter tag structure combined pilot voltage component are extracted respectively, the tag and the clutter scatterer are sensed based on the clutter tag structure combined pilot voltage component, and the tag antenna mode pilot voltage component is used for tag identification. The inverse scattering and compressed sensing algorithms are used for perception and identification to restore high-dimensional imaging information and reduce the number of required transceivers. The inverse scattering-based imaging method is combined with the impedance of the modulated tag to realize backscatter communication, so that the integrated sensing and backscatter communication system can realize simultaneous positioning, identification and backscatter communication of tags in a cluttered environment, thereby improving the backscatter communication performance.

[0152] See also Figure 6 , Figure 6 A structural block diagram of an integrated sensing and backscattering communication device based on backscattering provided in an embodiment of the present invention.

[0153] The present invention provides an integrated sensing and backscattering communication device based on backscattering, comprising:

[0154] The pilot modulation module 601 is used to modulate the open-circuit pilot signal of the tag to generate the pilot signal and the short-circuit pilot signal of the tag to generate the pilot signal after transmitting the pilot signal to the tag through the transmitting antenna, and backscatter the open-circuit pilot signal and the short-circuit pilot signal to the receiving antenna;

[0155] The pilot voltage determination module 602 is used to determine the tag antenna mode pilot voltage component and the clutter tag structure combined pilot voltage component according to the open-circuit pilot reception voltage generated by the receiving antenna based on the open-circuit pilot signal and the short-circuit pilot reception voltage generated by the short-circuit pilot signal;

[0156] The reflection coefficient determination module 603 is used to construct an underdetermined linear equation group based on the pilot voltage component of the tag antenna pattern and the pilot voltage component of the clutter tag structure combination by using a compressed sensing algorithm and optimize the solution to determine the reflection coefficient of the tag antenna pattern and the reflection coefficient of the clutter tag structure combination;

[0157] The signal transmission acquisition module 604 is used to transmit the data signal to the receiving antenna by using binary phase shift keying through the tag when the transmitting antenna activates the tag, and to collect the data receiving voltage of the receiving antenna;

[0158] The signal voltage calculation module 605 is used to respectively use the tag antenna pattern reflection coefficient and the clutter tag structure combination reflection coefficient to correspondingly determine the tag antenna pattern data voltage component and the clutter tag structure combination data voltage component of the data signal;

[0159] The signal demodulation module 606 is used to perform signal demodulation on the data receiving voltage, the clutter tag structure combined data voltage component and the tag antenna mode data voltage component to obtain a bit mapping symbol of the data signal.

[0160] Optionally, the pilot voltage determination module 602 is specifically configured to:

[0161] Collecting an open-circuit pilot reception voltage generated by a receiving antenna based on an open-circuit pilot signal and a short-circuit pilot reception voltage generated based on a short-circuit pilot signal;

[0162] The difference between the open circuit pilot receiving voltage and the short circuit pilot receiving voltage is halved to obtain the tag antenna mode pilot voltage component;

[0163] The open circuit pilot reception voltage and the short circuit pilot reception voltage are averaged to obtain the clutter label structure combined pilot voltage component.

[0164] Optionally, the reflection coefficient determination module 603 is specifically used for:

[0165] A first underdetermined linear equation system about the reflection coefficient of the clutter tag structure combination is constructed based on the clutter tag structure combination voltage component by using a compressed sensing algorithm;

[0166] A two-step iterative shrinkage threshold algorithm is used to optimize and solve the first underdetermined linear equations to determine the reflection coefficient of the clutter label structure combination;

[0167] A second underdetermined linear equation set about the tag antenna pattern reflection coefficient is constructed based on the tag antenna pattern voltage component by using a compressed sensing algorithm;

[0168] A two-step iterative shrinkage threshold algorithm is used to optimize and solve the second underdetermined linear equations to determine the tag antenna pattern reflection coefficient.

[0169] Optionally, the signal demodulation module 606 is specifically used for:

[0170] The data receiving voltage is subtracted from the clutter tag structure combined data voltage component to obtain the receiving signal of the receiving antenna;

[0171] The received signal and the tag antenna pattern data voltage component are input into a preset reverse communication model and demodulated through maximum ratio combining to obtain a bit mapping symbol of the data signal.

[0172] Optionally, the reverse communication model is specifically:

[0173] ;

[0174] In the formula, For the bit-mapped symbols of the received signal, is the voltage component vector of the tag antenna pattern, For the bitmap symbols, For the The noise of the bit-mapped symbols.

[0175] Optionally, the process of determining the voltage component of the tag antenna mode data is specifically as follows:

[0176] ;

[0177] The specific process of determining the voltage component of the clutter tag structure combined data is as follows:

[0178] ;

[0179] In the formula, For the transmitting antennas, For the A receiving antenna, is the voltage component of the tag antenna mode, is an imaginary number, is the angular frequency, is the vacuum permeability, is the standardization factor, is the region of interest where the tags and clutter scatterers are located, For the The field radiated by a receiving antenna operating in transmit mode with unit excitation, For the The transmitting antennas are located at The incident field generated at is the tag antenna pattern reflection coefficient, is the area of ​​each spatial pixel in the domain of interest, is the combined voltage component of the clutter tag structure, Combined reflection coefficients for clutter tag structures.

[0180] An embodiment of the present invention also provides a computer device, including a memory and a processor, wherein a computer program is stored in the memory; when the computer program is executed by the processor, the processor executes the steps of the integrated sensing and backscattering communication method based on backscattering as in any of the above embodiments.

[0181] An embodiment of the present invention further provides a computer-readable storage medium having a computer program / instruction stored thereon. When the computer program / instruction is executed by a processor, the steps of the integrated sensing and backscattering communication method based on backscattering as in any of the above embodiments are implemented.

[0182] An embodiment of the present invention further provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps of the integrated sensing and backscattering communication method based on backscattering as in any of the above embodiments.

[0183] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices and modules can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0184] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0185] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0186] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0187] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0188] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An integrated sensing and backscattering communication method based on backscattering, characterized in that: include: After transmitting the pilot signal to the tag through the transmitting antenna, modulating the tag to be in an open circuit state to generate an open circuit pilot signal of the pilot signal and in a short circuit state to generate a short circuit pilot signal of the pilot signal, and backscattering the open circuit pilot signal and the short circuit pilot signal to the receiving antenna; Determine a tag antenna mode pilot voltage component and a clutter tag structure combined pilot voltage component according to an open-circuit pilot reception voltage generated by the receiving antenna based on the open-circuit pilot signal and a short-circuit pilot reception voltage generated by the short-circuit pilot signal; A compressed sensing algorithm is used to construct an underdetermined linear equation group based on the pilot voltage component of the tag antenna pattern and the pilot voltage component of the clutter tag structure combination, and the underdetermined linear equation group is optimized and solved to correspondingly determine the reflection coefficient of the tag antenna pattern and the reflection coefficient of the clutter tag structure combination; When the transmitting antenna activates the tag, a data signal is transmitted to the receiving antenna by using binary phase shift keying through the tag, and a data receiving voltage of the receiving antenna is collected; The tag antenna pattern reflection coefficient and the clutter tag structure combination reflection coefficient are respectively used to correspondingly determine the tag antenna pattern data voltage component and the clutter tag structure combination data voltage component of the data signal; The data receiving voltage, the clutter tag structure combined data voltage component and the tag antenna mode data voltage component are combined to perform signal demodulation to obtain a bit mapping symbol of the data signal.

2. The integrated sensing and backscattering communication method based on backscattering according to claim 1 is characterized in that: The step of determining the tag antenna mode pilot voltage component and the clutter tag structure combined pilot voltage component according to the open circuit pilot reception voltage generated by the receiving antenna based on the open circuit pilot signal and the short circuit pilot reception voltage generated by the short circuit pilot signal comprises: collecting an open-circuit pilot reception voltage generated by the receiving antenna based on the open-circuit pilot signal and a short-circuit pilot reception voltage generated based on the short-circuit pilot signal; Taking half the difference between the open circuit pilot reception voltage and the short circuit pilot reception voltage to obtain a tag antenna mode pilot voltage component; A mean operation is performed on the open-circuit pilot reception voltage and the short-circuit pilot reception voltage to obtain a clutter label structure combined pilot voltage component.

3. The integrated sensing and backscattering communication method based on backscattering according to claim 1 is characterized in that: The method of constructing an underdetermined linear equation group based on the tag antenna pattern voltage component and the clutter tag structure combination voltage component through a compressed sensing algorithm and optimizing and solving the equation group, and correspondingly determining the tag antenna pattern reflection coefficient and the clutter tag structure combination reflection coefficient, includes: Constructing a first underdetermined linear equation group about the clutter tag structure combination reflection coefficient based on the clutter tag structure combination voltage component by a compressed sensing algorithm; A two-step iterative shrinkage threshold algorithm is used to optimize and solve the first underdetermined linear equations to determine the reflection coefficient of the clutter label structure combination; Constructing a second underdetermined linear equation group about the tag antenna pattern reflection coefficient based on the tag antenna pattern voltage component by a compressed sensing algorithm; A two-step iterative shrinkage threshold algorithm is used to optimize and solve the second underdetermined linear equations to determine the tag antenna pattern reflection coefficient.

4. The integrated sensing and backscattering communication method based on backscattering according to claim 1, characterized in that: The combining the data receiving voltage, the clutter tag structure combined data voltage component and the tag antenna mode data voltage component to perform signal demodulation to obtain the bit mapping symbol of the data signal includes: Subtracting the data receiving voltage from the clutter tag structure combined data voltage component to obtain a receiving signal of the receiving antenna; The received signal and the tag antenna pattern data voltage component are input into a preset reverse communication model and demodulated through maximum ratio combining to obtain a bit mapping symbol of the data signal.

5. The integrated sensing and backscattering communication method based on backscattering according to claim 4 is characterized in that: The reverse communication model is specifically: ； In the formula, For the bit-mapped symbols of the received signal, is the voltage component vector of the tag antenna pattern, For the bitmap symbols, For the The noise of the bit-mapped symbols.

6. The integrated sensing and backscattering communication method based on backscattering according to claim 1, characterized in that: The specific process of determining the voltage component of the tag antenna mode data is as follows: ； The process of determining the voltage component of the clutter tag structure combined data is specifically as follows: ； In the formula, For the transmitting antennas, For the A receiving antenna, is the voltage component of the tag antenna mode, is an imaginary number, is the angular frequency, is the vacuum permeability, is the standardization factor, is the region of interest where the tags and clutter scatterers are located, For the The field radiated by a receiving antenna operating in transmit mode with unit excitation, For the The transmitting antennas are located at The incident field generated at is the tag antenna pattern reflection coefficient, is the area of ​​each spatial pixel in the domain of interest, is the combined voltage component of the clutter tag structure, Combined reflection coefficients for clutter tag structures.

7. An integrated sensing and backscattering communication device based on backscattering, characterized in that: include: A pilot modulation module, configured to, after transmitting a pilot signal to a tag through a transmitting antenna, modulate an open-circuit pilot signal in which the tag is in an open circuit state to generate the pilot signal and a short-circuit pilot signal in which the tag is in a short circuit state to generate the pilot signal, and backscatter the open-circuit pilot signal and the short-circuit pilot signal to a receiving antenna; A pilot voltage determination module, configured to determine a tag antenna mode pilot voltage component and a clutter tag structure combined pilot voltage component according to an open-circuit pilot reception voltage generated by the receiving antenna based on the open-circuit pilot signal and a short-circuit pilot reception voltage generated by the short-circuit pilot signal; A reflection coefficient determination module is used to construct an underdetermined linear equation group based on the pilot voltage component of the tag antenna pattern and the pilot voltage component of the clutter tag structure combination by using a compressed sensing algorithm and optimize the solution to correspondingly determine the reflection coefficient of the tag antenna pattern and the reflection coefficient of the clutter tag structure combination; A signal transmission and acquisition module, used for transmitting a data signal to the receiving antenna by using binary phase shift keying through the tag when the transmitting antenna activates the tag, and acquiring a data receiving voltage of the receiving antenna; A signal voltage calculation module, used to respectively use the tag antenna pattern reflection coefficient and the clutter tag structure combination reflection coefficient to correspondingly determine the tag antenna pattern data voltage component and the clutter tag structure combination data voltage component of the data signal; The signal demodulation module is used to perform signal demodulation on the data receiving voltage, the clutter tag structure combined data voltage component and the tag antenna mode data voltage component to obtain a bit mapping symbol of the data signal.

8. A computer device, characterized in that: It comprises a memory and a processor, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the processor executes the steps of the integrated sensing and backscattering communication method based on backscattering as described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program / instruction stored thereon, characterized in that: When the computer program / instructions are executed by a processor, the steps of the integrated sensing and backscattering communication method based on backscattering as described in any one of claims 1 to 6 are implemented.

10. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the steps of the integrated sensing and backscattering communication method based on backscattering as described in any one of claims 1 to 6 are implemented.

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