Wireless network backscattering method and device supporting multi-label concurrency

Abstract

The invention provides a wireless network backscattering method and device supporting multi-label concurrence, which can be applied to the technical field of wireless communication. The wireless network backscattering method supporting multi-label concurrency comprises the following steps: in response to a received frequency shift signal and a reference field, processing a frequency domain of the frequency shift signal by using the reference field to obtain a channel coefficient; obtaining a first phase error corresponding to the first subcarrier according to the first subcarrier and the channel coefficient; obtaining a second phase error corresponding to the second subcarrier according to a first phase error corresponding to the first subcarrier and a second offset frequency of the second subcarrier relative to the predetermined subcarrier; and adjusting the first frequency spectrum according to a second phase error corresponding to the second subcarrier to obtain a target frequency spectrum, the first frequency spectrum being obtained by processing the frequency shift signal by using Fourier transform.

Description

Technical Field

[0001] The present disclosure relates to the field of wireless communication technologies, and more particularly to a wireless network backscattering method and apparatus supporting multi-tag concurrency. Background Art

[0002] Backscattering technologies with low power consumption are widely applied in energy-constrained communication fields. Moreover, backscattering technologies are also being applied to more fields, such as environmental perception, object tracking, target recognition, etc. However, in the case of large-scale concurrent transmission of frequency-shift signals, due to the limited total throughput of the system and the interference generated between multiple frequency-shift signals during transmission, it is difficult to distinguish the multiple frequency-shift signals received by the receiver, and thus subsequent operations on the frequency-shift signals cannot be performed.

[0003] In the process of implementing the above inventive concept, the inventors found that: in the related art, when existing frequency-shift signals are transmitted concurrently on a large scale, the frequency-shift signals interfere with each other, resulting in the frequency-shift signals received by the receiver being overlapping signals. Therefore, multiple frequency-shift signals can only be transmitted on non-interfering channels, which limits the number of multiplexed transmissions of frequency-shift signals and reduces the throughput of the system. Summary of the Invention

[0004] In view of the above problems, the present disclosure provides a wireless network backscattering method and apparatus supporting multi-tag concurrency.

[0005] According to a first aspect of the present disclosure, there is provided a wireless network backscattering method supporting multi-tag concurrency, including: in response to a received frequency-shift signal and a reference field, processing the frequency domain of the frequency-shift signal by using the reference field to obtain a channel coefficient, wherein the frequency domain is obtained by processing the time domain of the frequency-shift signal by using a Fourier transform, the reference field is used to characterize subcarriers in the frequency-shift signal whose spectrum is not covered, and the frequency-shift signal includes a first subcarrier and a second subcarrier; obtaining a first phase error corresponding to the first subcarrier according to the first subcarrier and the channel coefficient; obtaining a second phase error corresponding to the second subcarrier according to the first phase error corresponding to the first subcarrier and a second offset frequency of the second subcarrier relative to a predetermined subcarrier; and adjusting a first spectrum according to the second phase error corresponding to the second subcarrier to obtain a target spectrum, wherein the first spectrum is obtained by processing the frequency-shift signal by using a Fourier transform.

[0006] According to an embodiment of the present disclosure, in which, in response to the received frequency-shifted signal and the reference field, the frequency domain of the frequency-shifted signal is processed using the reference field to obtain a channel coefficient, including: processing the time domain of the frequency-shifted signal to obtain a frequency domain corresponding to the time domain of the frequency-shifted signal; processing the frequency domain corresponding to the time domain of the frequency-shifted signal using the reference field to obtain a channel coefficient.

[0007] According to an embodiment of the present disclosure, in which, according to the first subcarrier and the channel coefficient, a first phase error corresponding to the first subcarrier is obtained, including: obtaining a first excitation subcarrier corresponding to the first subcarrier from the excitation signal according to the first subcarrier; obtaining a first reconstructed subcarrier according to the channel coefficient and the first excitation subcarrier; obtaining a first phase error corresponding to the first subcarrier according to the first reconstructed subcarrier.

[0008] According to an embodiment of the present disclosure, in which the frequency-shifted signal includes a square wave signal, and the data signal segment of the square wave signal includes N data segments, N is an integer greater than 1, n is an integer greater than 1, and n ≤ N. According to the first reconstructed subcarrier, obtaining a first phase error corresponding to the first subcarrier includes: for the nth data segment, calculating the first reconstructed subcarrier corresponding to the nth data segment to obtain the phase of the square wave signal corresponding to the first subcarrier in the nth data segment; for the first subcarrier corresponding to the nth data segment, obtaining the phase error of the first subcarrier corresponding to the (n - 1)th data segment; obtaining a first initial phase error corresponding to the first subcarrier in the nth data segment according to the phase error of the first subcarrier corresponding to the (n - 1)th data segment and the phase of the square wave signal corresponding to the first subcarrier in the nth data segment; performing linear fitting on the first initial phase error corresponding to the first subcarrier in the nth data segment to obtain a first phase error corresponding to the first subcarrier in the nth data segment.

[0009] According to an embodiment of the present disclosure, wherein linear fitting is performed on a first initial phase error corresponding to a first subcarrier in an nth data segment to obtain a first phase error corresponding to the first subcarrier in the nth data segment, including: using fitting parameters, performing linear fitting on the first initial phase error corresponding to the first subcarrier in the nth data segment to obtain a first linearly fitted phase error corresponding to the first subcarrier in the nth data segment; when the difference between the first linearly fitted phase error corresponding to the first subcarrier in the nth data segment and the first initial phase error corresponding to the first subcarrier in the nth data segment is less than or equal to a predetermined error threshold, confirming the first initial phase error corresponding to the first subcarrier as the first phase error of the first subcarrier in the nth data segment; when the difference between the first linearly fitted phase error corresponding to the first subcarrier in the nth data segment and the first initial phase error corresponding to the first subcarrier in the nth data segment is greater than the predetermined error threshold, confirming the first linearly fitted phase error corresponding to the first subcarrier as the first phase error of the first subcarrier in the nth data segment.

[0010] According to an embodiment of the present disclosure, wherein a second phase error corresponding to a second subcarrier is obtained based on a first phase error corresponding to the first subcarrier and a first offset frequency of the second subcarrier relative to a predetermined subcarrier, including: performing linear fitting on the first phase error corresponding to the first subcarrier to obtain a first offset frequency of the first subcarrier relative to the predetermined subcarrier, wherein the offset frequency is a fitting slope obtained by linear fitting; performing quadratic linear fitting on the first offset frequency of the first subcarrier relative to the predetermined subcarrier to obtain a second offset frequency of the second subcarrier relative to the predetermined subcarrier; obtaining a second phase error corresponding to the second subcarrier based on the second offset frequency of the second subcarrier relative to the predetermined subcarrier and the first phase error corresponding to the first subcarrier.

[0011] According to an embodiment of the present disclosure, wherein a target spectrum is obtained by adjusting a first spectrum based on a second phase error corresponding to the second subcarrier, including: obtaining a second spectrum based on an excitation signal, a channel coefficient, a phase of a square wave signal corresponding to the first subcarrier, and the second phase error corresponding to the second subcarrier; eliminating the second spectrum from the first spectrum to obtain the target spectrum.

[0012] The second aspect of the present disclosure provides a wireless network backscattering method supporting multi-tag concurrency, which is applied to a backscattering device and includes: in response to a received excitation signal, generating a frequency-shifted signal according to the excitation signal and a square wave signal, where the excitation signal is sent by an excitation source to the backscattering device; sending the frequency-shifted signal and a reference field to a receiver, where the reference field is used to characterize subcarriers in the frequency-shifted signal whose spectrum is not covered, and the frequency-shifted signal includes a first subcarrier and a second subcarrier, so that the receiver can use the reference field to process the frequency domain of the frequency-shifted signal to obtain a channel coefficient, and the frequency domain is obtained by processing the time domain of the frequency-shifted signal using Fourier transform, obtaining a first phase error corresponding to the first subcarrier according to the first subcarrier and the channel coefficient; obtaining a second phase error corresponding to the second subcarrier according to the first phase error corresponding to the first subcarrier and a second offset frequency of the second subcarrier relative to a predetermined subcarrier; and adjusting a first spectrum according to the second phase error corresponding to the second subcarrier to obtain a target spectrum.

[0013] The third aspect of the present disclosure provides a wireless network backscattering device supporting multi-tag concurrency, which is applied to a receiver and includes: a processing module, configured to, in response to a received frequency-shifted signal and a reference field, process the frequency domain of the frequency-shifted signal using the reference field to obtain a channel coefficient, where the frequency domain is obtained by processing the time domain of the frequency-shifted signal using Fourier transform; the reference field is used to characterize subcarriers in the frequency-shifted signal whose spectrum is not covered, and the frequency-shifted signal includes a first subcarrier and a second subcarrier; a first obtaining module, configured to obtain a first phase error corresponding to the first subcarrier according to the first subcarrier and the channel coefficient; a second obtaining module, configured to obtain a second phase error corresponding to the second subcarrier according to the first phase error corresponding to the first subcarrier and a second offset frequency of the second subcarrier relative to a predetermined subcarrier; and an adjustment module, configured to adjust a first spectrum according to the second phase error corresponding to the second subcarrier to obtain a target spectrum, where the first spectrum is obtained by processing the frequency-shifted signal using Fourier transform.

[0014] The fourth aspect of the present disclosure provides a wireless backscatter device supporting multi-tag concurrency, which is applied to the backscatter device and includes: a generating module, configured to generate a frequency-shifted signal according to the received excitation signal and the square-wave signal in response to the received excitation signal, where the excitation signal is sent from an excitation source to the backscatter device; a transmitting module, configured to transmit the frequency-shifted signal and a reference field to a receiver, where the reference field is used to characterize the subcarriers in the frequency-shifted signal that are not covered by the spectrum. The frequency-shifted signal includes a first subcarrier and a second subcarrier, so that the receiver can use the reference field to process the frequency domain of the frequency-shifted signal to obtain a channel coefficient. The frequency domain is obtained by processing the time domain of the frequency-shifted signal using Fourier transform. According to the first subcarrier and the channel coefficient, a first phase error corresponding to the first subcarrier is obtained; according to the first phase error corresponding to the first subcarrier and a second offset frequency of the second subcarrier relative to a predetermined subcarrier, a second phase error corresponding to the second subcarrier is obtained; and according to the second phase error corresponding to the second subcarrier, the first spectrum is adjusted to obtain a target spectrum.

[0015] The fifth aspect of the present disclosure provides an electronic device, including: one or more processors; a memory, configured to store one or more programs, where when the one or more programs are executed by the one or more processors, the one or more processors are caused to execute the above method.

[0016] The sixth aspect of the present disclosure further provides a computer-readable storage medium, on which executable instructions are stored, and when the instructions are executed by a processor, the processor is caused to execute the above method.

[0017] The seventh aspect of the present disclosure further provides a computer program product, including a computer program, and when the computer program is executed by a processor, the above method is implemented.

[0018] According to the wireless network backscattering method and device supporting multi-tag concurrency of the present disclosure, in response to the received frequency-shifted signal and reference field, the frequency domain of the frequency-shifted signal is processed using the reference field to obtain the channel coefficient. According to the first subcarrier and the channel coefficient, the first phase error corresponding to the first subcarrier is obtained. According to the first phase error corresponding to the first subcarrier and the frequency offset of the second subcarrier relative to the predetermined subcarrier, the second phase error corresponding to the second subcarrier is obtained. The first spectrum is adjusted according to the second phase error corresponding to the second subcarrier to obtain the target spectrum, realizing the splitting of multiple overlapping frequency-shifted signals received by the receiver, avoiding that large-scale concurrent transmission makes multiple frequency-shifted signals indistinguishable, thereby affecting the receiver's extraction of data information from the frequency-shifted signals. Moreover, as the receiver can eliminate and split multiple overlapping frequency-shifted signals, the frequency-shifted signals can also be transmitted in a channel that will be interfered by other frequency-shifted signals, increasing the total number of multi-channel transmissions and improving the system throughput. Description of the Drawings

[0019] Through the following description of the embodiments of the present disclosure with reference to the drawings, the above content and other objects, features, and advantages of the present disclosure will become clearer. In the drawings:

[0020] Figure 1 Schematically shows an application scenario diagram of a wireless network backscattering method and device supporting multi-tag concurrency according to an embodiment of the present disclosure;

[0021] Figure 2 Schematically shows a flowchart of a wireless network backscattering method supporting multi-tag concurrency applied to a receiver according to an embodiment of the present disclosure;

[0022] Figure 3 Schematically shows a flowchart of obtaining the first phase error corresponding to the first subcarrier according to an embodiment of the present disclosure;

[0023] Figure 4 Schematically shows a flowchart of obtaining the second phase error corresponding to the second subcarrier according to an embodiment of the present disclosure;

[0024] Figure 5 Schematically shows a schematic diagram of the packet structure of a backscattering device according to an embodiment of the present disclosure;

[0025] Figure 6 Schematically shows a schematic diagram of the phase shift of the original frequency-shifted signal in the case of harmonic interference according to an embodiment of the present disclosure;

[0026] Figure 7 Schematically shows a schematic diagram after recursive processing of the original frequency-shifted signal in the case of harmonic interference according to an embodiment of the present disclosure;

[0027] Figure 8 Schematically shows a schematic diagram after linearly fitting the original frequency-shifted signal in the case of harmonic interference according to an embodiment of the present disclosure;

[0028] Figure 9 Schematically shows a schematic diagram of a frequency-shifted signal without interference elimination according to an embodiment of the present disclosure;

[0029] Figure 10 Schematically shows a schematic diagram of a frequency-shifted signal with interference elimination according to an embodiment of the present disclosure;

[0030] Figure 11 Schematically shows a schematic diagram of a system architecture according to an embodiment of the present disclosure;

[0031] Figure 12 Schematically shows a flowchart of a wireless network backscattering method supporting multi-tag concurrency applied to a backscattering device according to an embodiment of the present disclosure;

[0032] Figure 13 Schematically shows a structural block diagram of a wireless network backscattering device supporting multi-tag concurrency applied to a receiver according to an embodiment of the present disclosure;

[0033] Figure 14 Schematically shows a structural block diagram of a wireless network backscattering device supporting multi-tag concurrency applied to a backscattering device according to an embodiment of the present disclosure;

[0034] Figure 15 Schematically shows a block diagram of an electronic device suitable for a wireless network backscattering method supporting multi-tag concurrency according to an embodiment of the present disclosure. Detailed implementation manners

[0035] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the following detailed description, for the sake of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is obvious that one or more embodiments can also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present disclosure.

[0036] The terms used herein are merely for describing specific embodiments and are not intended to limit the present disclosure. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0037] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those of ordinary skill in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0038] In the case of using expressions such as "at least one of A, B, and C, etc.", generally, it should be interpreted according to the meaning commonly understood by those of ordinary skill in the art (for example, "a system having at least one of A, B, and C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0039] In the technical solution of the present invention, the user information involved (including but not limited to user personal information, user image information, user device information, such as location information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) are all information and data authorized by the user or fully authorized by all parties. And the processing of the relevant data, such as collection, storage, use, processing, transmission, provision, disclosure, and application, etc., all comply with relevant laws, regulations, and standards, take necessary confidentiality measures, do not violate public order and good customs, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0040] As the backscatter technology becomes more and more mature, the backscatter technology with low power consumption is also being applied to multiple technical fields, especially the communication field. In recent years, with the wide deployment of WiFi infrastructure, the WiFi-based backscatter technology has become an important research direction in backscatter communication. However, the existing technology is still limited to the performance optimization of the single-tag scenario. To improve the throughput of the system, researchers have started to research in the direction of parallel communication of multiple backscatter devices to improve the throughput capacity of the system.

[0041] However, in the case of large-scale concurrent transmission of multiple frequency-shift signals in the existing backscatter system, the frequency-shift signals will interfere with each other, resulting in a decrease in the signal strength of the frequency-shift signals, making it difficult for the receiver to distinguish after receiving the frequency-shift signals. In order to avoid mutual interference, it is necessary to transmit the frequency-shift signals in non-interfering channels, which limits the number of multiplexed concurrency and reduces the throughput of the system. During the research of the backscatter technology that supports multi-tag concurrency by researchers, it is found that in the related technology, due to the mutual interference between the existing frequency-shift signals during large-scale concurrent transmission, the frequency-shift signals received by the receiver are overlapping signals, and multiple frequency-shift signals can only be transmitted in non-interfering channels, which limits the number of multiplexed transmissions of the frequency-shift signals and reduces the throughput of the system.

[0042] In view of this, embodiments of the present disclosure provide a wireless network backscattering method supporting multi-tag concurrency, which is applied to a receiver and includes: in response to a received frequency-shifted signal and a reference field, processing the frequency domain of the frequency-shifted signal by using the reference field to obtain a channel coefficient, where the frequency domain is obtained by processing the time domain of the frequency-shifted signal by using a Fourier transform, the reference field is used to characterize subcarriers in the frequency-shifted signal whose spectrum is not covered, and the frequency-shifted signal includes a first subcarrier and a second subcarrier; obtaining a first phase error corresponding to the first subcarrier according to the first subcarrier and the channel coefficient; obtaining a second phase error corresponding to the second subcarrier according to the first phase error corresponding to the first subcarrier and a second offset frequency of the second subcarrier relative to a predetermined subcarrier; and adjusting a first spectrum according to the second phase error corresponding to the second subcarrier to obtain a target spectrum, where the first spectrum is obtained by processing the frequency-shifted signal by using a Fourier transform.

[0043] Figure 1 FIG. schematically shows an application scenario diagram of a wireless network backscattering method supporting multi-tag concurrency according to an embodiment of the present disclosure.

[0044] As [[ID=IO]] Figure 1 shown, an application scenario 100 according to this embodiment may include a first backscattering device 101, a second backscattering device 102, a third backscattering device 103, a network 104, and a receiver 105. The network 104 is used to provide a medium for communication links between the terminal devices 101, 102, 103, and the receiver 105. The network 104 may include various connection types, such as wired, wireless communication links, or fiber optic cables, etc.

[0045] A user may use at least one of the first backscattering device 101, the second backscattering device 102, and the third backscattering device 103 to interact with the server 105 through the network 104 to receive or send signals, etc.

[0046] The receiver 105 may be a server providing various services, such as receiving and processing signals sent by the user using the first backscattering device 101, the second backscattering device 102, and the third backscattering device 103 (for example only). The receiver 105 may analyze and process data such as received signals, and feedback the processing results (such as web pages, information, or data obtained or generated according to user requests) to the terminal device.

[0047] Note that the backscattering method supporting multi-tag concurrency provided by the embodiments of the present disclosure can generally be executed by the receiver 105. Correspondingly, the backscattering device supporting multi-tag concurrency provided by the embodiments of the present disclosure can generally be arranged in the receiver 105. The backscattering method supporting multi-tag concurrency provided by the embodiments of the present disclosure can also be executed by a server or a server cluster different from the receiver 105 and capable of communicating with the first terminal device 101, the second terminal device 102, the third backscattering device 103, and / or the receiver 105. Correspondingly, the backscattering device supporting multi-tag concurrency provided by the embodiments of the present disclosure can also be arranged in a server or a server cluster different from the receiver 105 and capable of communicating with the first backscattering device 101, the second backscattering device 102, the third backscattering device 103, and / or the receiver 105.

[0048] It should be understood that Figure 1 the numbers of the terminal devices, networks, and servers in

[0049] are merely illustrative. According to the implementation requirements, there can be any number of terminal devices, networks, and servers. Figure 1 Based on the scenario described below Figures 2 to 11 the backscattering method supporting multi-tag concurrency of the disclosed embodiments will be described in detail through

[0050] Figure 2 FIG. schematically shows a flowchart of a wireless network backscattering method supporting multi-tag concurrency according to an embodiment of the present disclosure.

[0051] As Figure 2 shown, the wireless network backscattering method supporting multi-tag concurrency of this embodiment includes operations S210 to S240.

[0052] In operation S210, in response to the received frequency-shifted signal and reference field, the frequency domain of the frequency-shifted signal is processed using the reference field to obtain the channel coefficient.

[0053] According to an embodiment of the present disclosure, the frequency domain is obtained by processing the time domain of the frequency-shifted signal using Fourier transform, and the reference field is used to characterize the subcarriers in the frequency-shifted signal that are not covered by the spectrum. The frequency-shifted signal includes a first subcarrier and a second subcarrier.

[0054] According to an embodiment of the present disclosure, the receiver can be a Wifi receiver.

[0055] According to an embodiment of the present disclosure, the WiFi signal emitted by the WiFi receiver can be an environmental signal packet, and the environmental signal packet can be characterized as an excitation signal.

[0056] According to an embodiment of the present disclosure, the receiver may receive multiple frequency-shifted signals.

[0057] According to an embodiment of the present disclosure, the frequency-shifted signal is obtained by processing an excitation signal and a square wave signal in a backscatter device.

[0058] According to an embodiment of the present disclosure, the frequency-shifted signal is obtained by multiplying the excitation signal by the square wave signal.

[0059] According to an embodiment of the present disclosure, the phase modulation of each excitation signal by the backscatter device can be characterized as modulating the excitation signal segment on the excitation signal to obtain signal data corresponding to each excitation signal segment.

[0060] According to an embodiment of the present disclosure, the signal data can be signal data 0 or signal data 1.

[0061] According to an embodiment of the present disclosure, for different phases of the square wave signal corresponding to the signal data of the excitation signal, the square wave signal with phase 0 corresponds to signal data 0, and the square wave signal with phase π corresponds to signal data 1.

[0062] According to an embodiment of the present disclosure, multiplying the excitation signal segment with signal data 0 of the excitation signal by the square wave signal with phase 0 causes a 0-phase shift in the phase of the excitation signal segment.

[0063] According to an embodiment of the present disclosure, multiplying the excitation signal segment with signal data 1 of the excitation signal by the square wave signal with phase π causes a π-phase shift in the phase of the excitation signal segment.

[0064] According to an embodiment of the present disclosure, the backscatter device modulates the data segment on the square wave signal to obtain tag data corresponding to each data segment.

[0065] According to an embodiment of the present disclosure, the tag data can be tag data 0 or tag data 1.

[0066] According to an embodiment of the present disclosure, the receiver can determine the data sent by the data segment according to the phase of the data segment in the received square wave signal.

[0067] For example, if the phase of the first data segment of the square wave signal is 0, the tag data sent by the first data segment is 0 bit, and if the phase of the second data segment of the square wave signal is π, the tag data sent by the first data segment is 1 bit.

[0068] According to an embodiment of the present disclosure, the frequency-shifted signal may include multiple frequency-shifted signal segments, and each frequency-shifted signal segment may include 64 backscatter subcarriers.

[0069] According to an embodiment of the present disclosure, the excitation signal may include a plurality of excitation signal segments, and each excitation signal segment may include 64 excitation subcarriers.

[0070] According to an embodiment of the present disclosure, after generating the reference field, the backscatter device sends the reference field and the frequency-shifted signal to the receiver.

[0071] According to an embodiment of the present disclosure, after the receiver receives the frequency-shifted signal and the reference field, the time domain of the frequency-shifted signal segment of the frequency-shifted signal is first processed using the fast Fourier transform to obtain the frequency domain of the frequency-shifted signal segment.

[0072] According to an embodiment of the present disclosure, the receiver calculates the frequency domain of the frequency-shifted signal segment after being processed by the fast Fourier transform according to the received reference field to obtain the channel coefficients of the channels for transmitting each frequency-shifted signal.

[0073] According to an embodiment of the present disclosure, the first subcarrier may be characterized as an unperturbed backscatter subcarrier, and the first subcarrier may also be characterized as a subcarrier whose spectrum in the frequency-shifted signal is not covered.

[0074] According to an embodiment of the present disclosure, the second subcarrier may be characterized as a perturbed backscatter subcarrier, and the second subcarrier may also be characterized as a subcarrier whose spectrum in the frequency-shifted signal is covered.

[0075] According to an embodiment of the present disclosure, the unperturbed backscatter subcarrier may be characterized as the backscatter subcarrier included in the frequency-shifted signal segment in the spectrum where the frequency-shifted signal is not covered by other frequency-shifted signals, and the unperturbed backscatter subcarrier may also be characterized as a clean subcarrier.

[0076] For example, the spectrum includes two frequency-shifted signals. The first frequency-shifted signal segment of the first frequency-shifted signal is not covered by the frequency-shifted signal segment of the second frequency-shifted signal. Then, in the first frequency-shifted signal, the unperturbed backscatter subcarrier is the backscatter subcarrier in the first frequency-shifted signal segment of the first frequency-shifted signal.

[0077] According to an embodiment of the present disclosure, the perturbed backscatter subcarrier may be characterized as the backscatter subcarrier included in the frequency-shifted signal segment in the spectrum that is covered by other frequency-shifted signals.

[0078] According to an embodiment of the present disclosure, all the backscatter subcarriers in the frequency-shifted signal may be unperturbed backscatter subcarriers, or some of the backscatter subcarriers in the frequency-shifted signal may be unperturbed backscatter subcarriers. That is, in the spectrum, the frequency-shifted signal may not be covered by other frequency-shifted signals at all, or some of the frequency-shifted signals in the frequency-shifted signal may be covered by other frequency-shifted signals.

[0079] According to an embodiment of the present disclosure, the reference field may be a symbol string composed of the unperturbed backscattered subcarriers in all the frequency-shifted signals, that is, the reference field may include the subcarriers whose spectra are not covered in all the frequency-shifted signals.

[0080] In operation S220, according to the first subcarrier and the channel coefficient, a first phase error corresponding to the first subcarrier is obtained.

[0081] According to an embodiment of the present disclosure, by processing the first subcarrier using the channel coefficient, a first phase error corresponding to the first subcarrier can be obtained.

[0082] According to an embodiment of the present disclosure, the first phase error may be characterized as the phase error of the frequency-shifted signal corresponding to the first subcarrier.

[0083] In operation S230, according to the first phase error corresponding to the first subcarrier and the second offset frequency of the second subcarrier relative to the predetermined subcarrier, a second phase error corresponding to the second subcarrier is obtained.

[0084] According to an embodiment of the present disclosure, both the first subcarrier and the second subcarrier have a phase error and an offset frequency.

[0085] According to an embodiment of the present disclosure, the predetermined subcarrier may be characterized as a subcarrier without an offset frequency, that is, a backscattered subcarrier with an offset frequency of 0, and the predetermined subcarrier is an ideal subcarrier.

[0086] According to an embodiment of the present disclosure, the second phase error may be characterized as the phase error of the frequency-shifted signal corresponding to the second subcarrier.

[0087] In operation S240, the first spectrum is adjusted according to the second phase error corresponding to the second subcarrier to obtain a target spectrum.

[0088] According to an embodiment of the present disclosure, the first spectrum is obtained by processing the frequency-shifted signal using Fourier transform.

[0089] According to an embodiment of the present disclosure, the first spectrum may be characterized as the spectrum containing all the frequency-shifted signals.

[0090] According to an embodiment of the present disclosure, while processing the time domain of all the frequency-shifted signals using Fourier transform, a spectrum containing all the frequency-shifted signals, that is, the first spectrum, can be obtained.

[0091] According to an embodiment of the present disclosure, the spectrum of the target frequency-shifted signal corresponding to the second phase error is determined according to the second phase error.

[0092] According to an embodiment of the present disclosure, the target spectrum may be characterized as the spectrum that does not contain the spectrum of the target frequency-shifted signal.

[0093] According to an embodiment of the present disclosure, in the first spectrum, the spectrum of the target frequency-shifted signal covers the spectra of multiple frequency-shifted signals other than the target frequency-shifted signal, so that the receiver cannot process the multiple frequency-shifted signals other than the target frequency-shifted signal.

[0094] According to an embodiment of the present disclosure, in the target spectrum, since the spectrum of the target frequency-shifted signal is not included, the spectra of multiple frequency-shifted signals other than the target frequency-shifted signal can be revealed, so that the receiver can process the multiple frequency-shifted signals other than the target frequency-shifted signal.

[0095] According to an embodiment of the present disclosure, in response to the received frequency-shifted signal and the reference field, the frequency domain of the frequency-shifted signal is processed using the reference field to obtain a channel coefficient. According to the first subcarrier and the channel coefficient, a first phase error corresponding to the first subcarrier is obtained. According to the first phase error corresponding to the first subcarrier and the second offset frequency of the second subcarrier relative to the predetermined subcarrier, a second phase error corresponding to the second subcarrier is obtained. The first spectrum is adjusted according to the second phase error corresponding to the second subcarrier to obtain a target spectrum, realizing the splitting of multiple overlapping frequency-shifted signals received by the receiver, avoiding that large-scale concurrent transmission makes the multiple frequency-shifted signals indistinguishable, thereby affecting the receiver's extraction of data information from the frequency-shifted signals. Moreover, as the receiver can eliminate and split multiple overlapping frequency-shifted signals, the frequency-shifted signals can also be transmitted in a channel that will be interfered by other frequency-shifted signals, increasing the total number of multi-channel transmissions and improving the throughput of the system.

[0096] According to an embodiment of the present disclosure, wherein, in response to the received frequency-shifted signal and the reference field, processing the frequency domain of the frequency-shifted signal using the reference field to obtain a channel coefficient includes:

[0097] According to an embodiment of the present disclosure, the time domain of the frequency-shifted signal is processed to obtain a frequency domain corresponding to the time domain of the frequency-shifted signal.

[0098] According to an embodiment of the present disclosure, the time domain of the frequency-shifted signal segment of the frequency-shifted signal obtained by multiplying the square wave signal and the excitation signal is converted into the frequency domain of the signal segment.

[0099] According to an embodiment of the present disclosure, the time domain of the frequency-shifted signal segment of the frequency-shifted signal can be converted into the frequency domain of the frequency-shifted signal segment through fast Fourier transform.

[0100] According to an embodiment of the present disclosure, a backscatter device can be determined in advance from multiple backscatter devices as the leader backscatter device. When multiple backscatter devices generate square wave signals simultaneously, in the sequence signal segment, only the leader square wave signal generated by the leader backscatter device contains a preamble for reflecting the excitation signal. Then, the square wave signal is multiplied by the excitation signal to obtain a frequency-shifted signal, and the leader square wave signal is multiplied by the excitation signal to obtain a leader frequency-shifted signal, so as to avoid interference between multiple frequency-shifted signals during the transmission of multiple frequency-shifted signals, resulting in damage to the preamble.

[0101] According to an embodiment of the present disclosure, the received frequency-shifted signal by the receiver includes the leader frequency-shifted signal whose spectrum is not covered in the sequence signal segment of the frequency-shifted signal. The non-damaged short training sequence (STFs) and long training sequence (LTFs) are included in the leader frequency-shifted signal whose spectrum is not covered. The receiver can calculate the frame boundary point of the frequency-shifted signal based on the short training sequence and the long training sequence.

[0102] According to an embodiment of the present disclosure, the channel coefficient is obtained by processing the frequency domain corresponding to the time domain of the frequency-shifted signal using a reference field.

[0103] According to an embodiment of the present disclosure, based on the least squares method, the channel coefficient of the channel for transmitting each frequency-shifted signal is obtained by using the reference field to process the frequency domain corresponding to the time domain of each frequency-shifted signal.

[0104] According to an embodiment of the present disclosure, the channel coefficient for transmitting the frequency-shifted signal can be calculated according to formula (1), and formula (1) is shown as follows.

[0105]

[0106] Among them, can be characterized as the channel coefficient of the channel for transmitting the frequency-shifted signal, q can be characterized as the qth data segment in the reference stage of the square wave signal. In the reference stage of the square wave signal, each square wave signal only has two data segments. Therefore, the maximum value of q is 2, y b (q) can be characterized as the frequency-shifted signal corresponding to the qth data segment, h BS can be characterized as the channel parameter for transmitting the frequency-shifted signal, x(q) can be characterized as the excitation signal corresponding to the qth data segment, φ t (q) can be characterized as the phase corresponding to the qth data segment on the square wave signal.

[0107] According to an embodiment of the present disclosure, by performing the above processing on each frequency-shifted signal, the channel coefficient of each channel for transmitting each frequency-shifted signal can be obtained.

[0108] According to an embodiment of the present disclosure, the process of solving the channel coefficient of the channel for transmitting the frequency-shifted signal and detecting the frame boundary of the frequency-shifted signal can be collectively referred to as the functional recovery of the preamble of the frequency-shifted signal.

[0109] According to an embodiment of the present disclosure, by processing the time domain of the frequency-shifted signal to obtain the frequency domain corresponding to the time domain of the frequency-shifted signal, and then processing the frequency domain corresponding to the time domain of the frequency-shifted signal according to the reference field, the channel coefficient for transmitting the frequency-shifted signal is obtained, realizing the accurate determination of the channel coefficient for transmitting each frequency-shifted signal. At the same time, the frame boundary points of the frequency-shifted signal are also accurately determined, ensuring that the function of the preamble of each frequency-shifted signal will not be damaged during transmission, and the receiver can perform detection calculations based on the preamble of each received frequency-shifted signal to ensure the normal function of the preamble.

[0110] Figure 3 Schematically shows a flowchart of obtaining the first phase error corresponding to the first subcarrier according to an embodiment of the present disclosure.

[0111] As Figure 3 shown, the backscattering method supporting multi-tag concurrency in this embodiment includes operations S310 to S330.

[0112] According to an embodiment of the present disclosure, obtaining the first phase error corresponding to the first subcarrier according to the first subcarrier and the channel coefficient includes:

[0113] In operation S310, according to the first subcarrier, the first excitation subcarrier corresponding to the first subcarrier is obtained from the excitation signal.

[0114] According to an embodiment of the present disclosure, the receiver can receive the frequency-shifted signal and can also receive the excitation signal emitted by the excitation source.

[0115] According to an embodiment of the present disclosure, the receiver selects the first excitation subcarrier corresponding to the first subcarrier from the excitation signal according to the first subcarrier in the frequency-shifted signal.

[0116] According to an embodiment of the present disclosure, the first excitation subcarrier can be characterized as the subcarrier corresponding to the first subcarrier extracted from the excitation signal.

[0117] According to an embodiment of the present disclosure, the excitation source can be represented by TX, and the first excitation subcarrier can be represented by TX subcarrier.

[0118] According to an embodiment of the present disclosure, the receiver can be represented by RX.

[0119] For example, according to the first subcarrier in the received frequency-shifted signal A, the TX subcarrier corresponding to the first subcarrier is selected from the excitation signal.

[0120] In operation S320, a first reconstructed subcarrier is obtained according to the channel coefficient and the first excitation subcarrier.

[0121] According to an embodiment of the present disclosure, the channel coefficient is added to the first excitation subcarrier to obtain a first reconstructed subcarrier.

[0122] According to an embodiment of the present disclosure, the first reconstructed subcarrier can be characterized as the subcarrier obtained by adding the channel coefficient to the first excitation subcarrier.

[0123] According to an embodiment of the present disclosure, the first reconstructed subcarrier is the subcarrier corresponding to the first subcarrier in the frequency-shifted signal.

[0124] According to an embodiment of the present disclosure, the channel coefficient for transmitting the frequency-shifted signal is added to the first excitation subcarrier to reconstruct the first subcarrier whose spectrum in the frequency-shifted signal is not covered.

[0125] For example, the channel for transmitting the frequency-shifted signal A is channel a, and the channel coefficient of channel a is added to the TX subcarrier to reconstruct the first subcarrier whose spectrum in the frequency-shifted signal A is not covered.

[0126] According to an embodiment of the present disclosure, since the frequency-shifted signal is a signal obtained by multiplying the excitation signal and the square wave signal, the receiver cannot obtain the signal containing only the excitation signal from the frequency-shifted signal. Therefore, the receiver adds the channel coefficient to the first excitation subcarrier according to the directly received excitation signal to obtain the first reconstructed subcarrier, in order to reconstruct the subcarrier corresponding to the first subcarrier using the subcarrier in the signal containing only the excitation signal.

[0127] According to an embodiment of the present disclosure, the first reconstructed subcarrier can be calculated according to formula (2), and formula (2) is shown as follows.

[0128]

[0129] Wherein, n can be characterized as the nth frequency-shifted signal segment in the data signal segment of the frequency-shifted signal, can be characterized as the first reconstructed subcarrier of the nth frequency-shifted signal segment in the data signal segment of the frequency-shifted signal, φ ce (n) can be characterized as the phase error of the frequency-shifted signal corresponding to the first subcarrier in the nth frequency-shifted signal segment in the data signal segment of the frequency-shifted signal, C can be characterized as the set containing all the first subcarriers in the frequency-shifted signal, can be characterized as the channel coefficient of the channel for transmitting the frequency-shifted signal containing the nth frequency-shifted signal segment, x(n) can be characterized as the excitation signal corresponding to the nth frequency-shifted signal segment, φ t(n) can be characterized as the phase of the square wave signal corresponding to the n-th frequency-shifted signal segment in the frequency-shifted signal.

[0130] In operation S330, according to the first reconstructed subcarrier, a first phase error corresponding to the first subcarrier is obtained.

[0131] According to an embodiment of the present disclosure, since according to the first subcarrier, a first excitation subcarrier corresponding to the first subcarrier is obtained from the excitation signal, and according to the channel coefficient and the first excitation subcarrier, the channel coefficient is added to the first excitation subcarrier to obtain the first reconstructed subcarrier, the subcarrier corresponding to the first subcarrier is reconstructed, and the first phase error corresponding to the first subcarrier is obtained, which facilitates confirming the phase error corresponding to the second subcarrier.

[0132] According to an embodiment of the present disclosure, the frequency-shifted signal includes a square wave signal, and N data segments are included in the data signal segment of the square wave signal, where N is an integer greater than 1, n is an integer greater than 1, and n ≤ N.

[0133] According to an embodiment of the present disclosure, obtaining a first phase error corresponding to the first subcarrier according to the first reconstructed subcarrier includes:

[0134] According to an embodiment of the present disclosure, for the n-th data segment, the first reconstructed subcarrier corresponding to the n-th data segment is calculated to obtain the phase of the square wave signal corresponding to the first subcarrier in the n-th data segment.

[0135] According to an embodiment of the present disclosure, a total of N data segments are included in the data signal segment of the square wave signal, and each data segment corresponds to a tag data. Therefore, a total of N tag data are included in the data signal segment of the square wave signal.

[0136] According to an embodiment of the present disclosure, for the n-th data segment, the phase of the square wave signal corresponding to the first subcarrier in the n-th data segment is calculated.

[0137] According to an embodiment of the present disclosure, the phase of the square wave signal corresponding to the first subcarrier in the n-th data segment can be calculated according to formula (3), and formula (3) is shown as follows.

[0138]

[0139] Wherein, can be characterized as the phase of the square wave signal corresponding to the first subcarrier in the n-th frequency-shifted data segment, k can be characterized as the serial number of the first subcarrier in the n-th frequency-shifted data segment, y b (k,n) can be characterized as the frequency-shifted signal of the k-th first subcarrier in the n-th frequency-shifted data segment, can be characterized as the first reconstructed subcarrier corresponding to the k-th first subcarrier in the n-th frequency-shifted data segment, φt (n) ∈ {0, π} can be characterized as having two phases of the square wave signal corresponding to the nth frequency-shifted data segment, which are 0 phase and π phase respectively.

[0140] According to an embodiment of the present disclosure, the first reconstructed subcarrier and the frequency-shifted signal can be processed by maximum likelihood estimation to calculate the minimum Euclidean distance.

[0141] According to an embodiment of the present disclosure, by calculating the nth data segment to obtain the phase of the square wave signal corresponding to the first subcarrier in the frequency-shifted signal, the demodulation of the phase of the square wave signal corresponding to the first subcarrier in the nth data segment is achieved, so as to facilitate generating the spectrum of the target frequency-shifted signal and eliminating it in the first spectrum.

[0142] According to an embodiment of the present disclosure, for the first subcarrier corresponding to the nth data segment, the phase error of the first subcarrier corresponding to the (n - 1)th data segment is obtained.

[0143] According to an embodiment of the present disclosure, the phase error of the first subcarrier in the (n - 1)th data segment and the phase error of the first subcarrier in the nth data segment in the frequency-shifted signal are initialized to establish an initial constraint condition for the phase error. The initial constraint condition is that the phase error of the frequency-shifted signal corresponding to the first subcarrier in the (n - 1)th data segment is equal to the phase error of the frequency-shifted signal corresponding to the first subcarrier in the nth data segment. The initial constraint condition can be shown as formula (4).

[0144] φ ce φ(k, n) = ce φ(k, n - 1) (4);

[0145] where, φ ce φ(k, n) can be characterized as the phase error of the frequency-shifted signal corresponding to the kth first subcarrier in the nth data segment of the frequency-shifted signal, and φ ce φ(k, n - 1) can be characterized as the phase error of the frequency-shifted signal corresponding to the kth first subcarrier in the (n - 1)th data segment of the frequency-shifted signal.

[0146] For example, in the data signal segment of the frequency-shifted signal, the label data of the first data segment is 0, and the label data of the second data segment is 1. The established initial constraint condition is that the phase error of the frequency-shifted signal corresponding to the first subcarrier in the first data segment is equal to the phase error of the frequency-shifted signal corresponding to the first subcarrier in the second data segment.

[0147] According to an embodiment of the present disclosure, based on the phase error of the first subcarrier corresponding to the (n - 1)-th data segment and the phase of the square wave signal corresponding to the first subcarrier in the n-th data segment, the first initial phase error corresponding to the first subcarrier in the n-th data segment is obtained.

[0148] According to an embodiment of the present disclosure, based on the initial constraint condition, the phase error of the frequency-shifted signal corresponding to the first subcarrier under the (n - 1)-th data segment is equal to the phase error of the frequency-shifted signal corresponding to the first subcarrier under the n-th data segment. Thus, based on the phase error of the frequency-shifted signal corresponding to the k-th first subcarrier under the (n - 1)-th data segment and the phase of the square wave signal corresponding to the first subcarrier in the n-th data segment, calculations can be performed to obtain the first initial phase error of the frequency-shifted signal corresponding to the first subcarrier in the n-th data segment.

[0149] According to an embodiment of the present disclosure, the first initial phase error can be calculated according to formula (5), and formula (5) is shown as follows.

[0150]

[0151] Wherein, φ ce (k,n) can represent the phase error of the frequency-shifted signal corresponding to the k-th first subcarrier in the n-th data segment, and y b (k,n) can represent the frequency-shifted signal corresponding to the k-th first subcarrier in the n-th data segment. can represent the channel coefficient of the channel of the k-th first subcarrier in the n-th data segment for transmitting the frequency-shifted signal, and j can represent the complex conjugate. can represent the phase of the square wave signal corresponding to the k-th first subcarrier in the n-th data segment of the frequency-shifted signal.

[0152] According to an embodiment of the present disclosure, linear fitting is performed on the first initial phase error corresponding to the first subcarrier in the n-th data segment to obtain the first phase error corresponding to the first subcarrier in the n-th data segment.

[0153] According to an embodiment of the present disclosure, linear fitting is performed on the first initial phase error corresponding to the first subcarrier in the n-th data segment by using the fitting parameters. The fitting parameters can be composed of the first initial phase error corresponding to the first subcarrier in the 1st data segment to the first initial phase error corresponding to the first subcarrier in the 20th data segment.

[0154] According to an embodiment of the present disclosure, since the first reconstructed subcarrier corresponding to the nth data segment is first calculated for the nth data segment, the phase of the square wave signal corresponding to the first subcarrier in the nth data segment in the frequency-shifted signal is obtained. Then, a predetermined constraint condition is established for the phase error of the first subcarrier corresponding to the nth data segment and the phase error of the first subcarrier corresponding to the (n - 1)th data segment. According to the predetermined constraint condition, using the phase error corresponding to the first subcarrier in the (n - 1)th data segment and the phase of the square wave signal corresponding to the first subcarrier in the previously obtained nth data segment for calculation, the first initial phase error of the square wave signal corresponding to the first subcarrier is obtained. Then, linear fitting is performed on the first initial phase error to obtain the first phase error of the frequency-shifted signal corresponding to the first subcarrier, realizing the demodulation of the phase of the square wave signal corresponding to the frequency-shifted signal. Also, since there may be errors in the phase of the demodulated square wave signal, the phase error of the frequency-shifted signal is calculated to avoid the phase of the frequency-shifted signal and the square wave signal with errors affecting subsequent demodulation, improving the accuracy of the phase of the square wave signal.

[0155] According to an embodiment of the present disclosure, performing linear fitting on the first initial phase error corresponding to the first subcarrier in the nth data segment to obtain the first phase error corresponding to the first subcarrier in the nth data segment includes:

[0156] [[ID=D6]]According to an embodiment of the present disclosure, using the fitting parameter to perform linear fitting on the first initial phase error corresponding to the first subcarrier in the nth data segment to obtain the first linearly fitted phase error corresponding to the first subcarrier in the nth data segment.

[0157] According to an embodiment of the present disclosure, the fitting parameter can be represented by formula (6), and formula (6) is as follows.

[0158] {φ ce (k,n),m < n} (6);

[0159] Wherein, {φ ce (k,n),m < n} can be characterized as the fitting parameter, n can be characterized as the nth data segment in the data signal segment of the frequency-shifted signal, m can be characterized as the mth data segment under the data signal segment, and m < n.

[0160] According to an embodiment of the present disclosure, the first linearly fitted phase error after fitting with the fitting parameter can be represented by to represent.

[0161] According to an embodiment of the present disclosure, the first linearly fitted phase error can be characterized as the phase error obtained after linear fitting of the first initial phase error.

[0162] According to an embodiment of the present disclosure, when the difference between the first linear fitting phase error corresponding to the first subcarrier in the nth data segment and the first initial phase error corresponding to the first subcarrier in the nth data segment is less than or equal to a predetermined error threshold, it is confirmed that the first initial phase error corresponding to the first subcarrier is the first phase error of the first subcarrier in the nth data segment.

[0163] According to an embodiment of the present disclosure, the predetermined error threshold can be set to

[0164] According to an embodiment of the present disclosure, based on the first linear fitting phase error corresponding to the first subcarrier in the nth data segment in the data signal segment of the frequency-shifted signal and the first initial phase error corresponding to the first subcarrier in the nth data segment in the data signal segment of the frequency-shifted signal, the difference between the two is calculated.

[0165] According to an embodiment of the present disclosure, based on the calculated difference and the predetermined error threshold, when the calculated difference is less than or equal to the predetermined error threshold, it is confirmed that the first initial phase error corresponding to the first subcarrier in the nth data segment in the data signal segment of the frequency-shifted signal is the first phase error of the first subcarrier corresponding to the nth data segment.

[0166] According to an embodiment of the present disclosure, when the difference between the first linear fitting phase error corresponding to the first subcarrier in the nth data segment and the first initial phase error corresponding to the first subcarrier in the nth data segment is greater than the predetermined error threshold, it is confirmed that the first linear fitting phase error corresponding to the first subcarrier is the first phase error of the first subcarrier in the nth data segment.

[0167] According to an embodiment of the present disclosure, based on the calculated difference and the predetermined error threshold, when the calculated difference is greater than the predetermined error threshold, it is confirmed that the first linear fitting phase error corresponding to the first subcarrier in the nth data segment in the data signal segment of the frequency-shifted signal is the first phase error of the first subcarrier corresponding to the nth data segment.

[0168] According to an embodiment of the present disclosure, since the first initial phase error corresponding to the first subcarrier in the nth data segment of the frequency-shifted signal data signal segment is linearly fitted using the fitting parameter, the first linearly fitted phase error corresponding to the first subcarrier in the nth data segment is obtained, and the difference between the first initial phase error and the first linearly fitted phase error corresponding to the first subcarrier in the nth data segment is calculated. When the difference is less than or equal to the predetermined error threshold, it is confirmed that the first initial phase error corresponding to the first subcarrier in the nth data segment is the first phase error. When the difference is greater than the predetermined error threshold, it is confirmed that the first linearly fitted phase error corresponding to the first subcarrier in the nth data segment is the first phase error, realizing the constraint through the predetermined error threshold, thereby accurately estimating the first phase error corresponding to the first subcarrier in the nth data segment, reducing the influence of subsequent demodulation, and facilitating the demodulation of the frequency-shifted signal.

[0169] According to an embodiment of the present disclosure, the processes of reconstructing the first subcarrier in the nth data segment of the frequency-shifted signal, demodulating the phase of the square wave signal corresponding to the first subcarrier in the nth data segment, and calculating the phase error of the frequency-shifted signal corresponding to the first subcarrier in the nth data segment can be collectively referred to as subcarrier-level demodulation of the subcarriers of the frequency-shifted signal.

[0170] Figure 4 Schematically shows a flowchart of obtaining the second phase error corresponding to the second subcarrier according to an embodiment of the present disclosure.

[0171] As Figure 4 shown, the backscattering method supporting multi-tag concurrency in this embodiment includes operations S410 to S430.

[0172] According to an embodiment of the present disclosure, wherein obtaining the second phase error corresponding to the second subcarrier according to the first phase error corresponding to the first subcarrier and the first offset frequency of the second subcarrier relative to the predetermined subcarrier includes:

[0173] In operation S410, the first phase error corresponding to the first subcarrier is linearly fitted to obtain the first offset frequency of the first subcarrier relative to the predetermined subcarrier.

[0174] According to an embodiment of the present disclosure, wherein the first offset frequency can be characterized as the fitting slope obtained in the linear fitting.

[0175] According to an embodiment of the present disclosure, the first phase error corresponding to the first subcarrier is fitted to obtain the first target phase error corresponding to the first subcarrier, and the fitting slope obtained during the fitting process is the first offset frequency of the first subcarrier relative to the predetermined subcarrier.

[0176] In operation S420, a second - order linear fit is performed on the first offset frequency of the first sub - carrier relative to a predetermined sub - carrier to obtain the second offset frequency of the second sub - carrier relative to the predetermined sub - carrier.

[0177] According to an embodiment of the present disclosure, the second offset frequency is the offset frequency corresponding to the second sub - carrier, and the second offset frequency may also be the offset frequency corresponding to the backscattered sub - carrier affected by interference.

[0178] In operation S430, based on the second offset frequency of the second sub - carrier relative to the predetermined sub - carrier and the first phase error corresponding to the first sub - carrier, the second phase error corresponding to the second sub - carrier is obtained.

[0179] According to an embodiment of the present disclosure, in the entire processing of the frequency - shifted signal by the receiver, a total of 3 fits are included. The first linear fit is in sub - carrier - level demodulation, fitting the phase error of the frequency - shifted signal corresponding to the first sub - carrier in the nth data segment. The second linear fit is to prevent noise from affecting the phase error obtained in the first linear fit, thereby affecting subsequent demodulation. Thus, a second linear fit is performed on the phase error of the frequency - shifted signal corresponding to the first sub - carrier in the nth data segment obtained. The fitting slope obtained in the fit is used as the first offset frequency. Then, a third linear fit is performed on the first offset frequency obtained in the second linear fit to obtain the second offset frequency.

[0180] According to an embodiment of the present disclosure, since a linear fit is performed on the first phase error corresponding to the first sub - carrier to obtain the first offset frequency of the first sub - carrier relative to the predetermined sub - carrier, and then a second linear fit is performed on the obtained first offset frequency of the first sub - carrier relative to the predetermined sub - carrier to obtain the second offset frequency of the second sub - carrier relative to the predetermined sub - carrier, and the second phase error corresponding to the second sub - carrier is calculated based on the second offset frequency and the first phase error corresponding to the first sub - carrier, accurate determination of the second phase error is achieved, so as to obtain the spectrum of the frequency - shifted signal to be finally eliminated based on the second phase error and other data. Thus, the receiver can accurately eliminate the spectrum of the target frequency - shifted signal, identify the remaining frequency - shifted signals, and perform subsequent operations on them.

[0181] According to an embodiment of the present disclosure, adjusting the first spectrum according to the second phase error corresponding to the second sub - carrier to obtain the target spectrum includes:

[0182] According to an embodiment of the present disclosure, based on the excitation signal, the channel coefficient, the phase of the square - wave signal corresponding to the first sub - carrier, and the second phase error corresponding to the second sub - carrier, the second spectrum is obtained.

[0183] According to an embodiment of the present disclosure, the receiver calculates based on the received excitation signal, the channel coefficient of the channel for transmitting the frequency-shifted signal, the phase of the square wave signal corresponding to the first subcarrier in each data segment of the frequency-shifted signal, and the second phase error corresponding to the second subcarrier in each data segment of the frequency-shifted signal, to obtain the spectrum of the target frequency-shifted signal to be eliminated.

[0184] According to an embodiment of the present disclosure, the target frequency-shifted signal can be characterized as a frequency-shifted signal that has been demodulated and is to be eliminated.

[0185] According to an embodiment of the present disclosure, the second spectrum can be characterized as a spectrum that only contains the spectrum of the target frequency-shifted signal to be eliminated.

[0186] According to an embodiment of the present disclosure, the target frequency-shifted signal obtained after demodulation can be calculated by formula (7), and formula (7) is shown as follows.

[0187]

[0188] Wherein, can be characterized as the l-th subcarrier of the i-th frequency-shifted signal after demodulation in the n-th data segment. At this time, the subcarrier can not only be an unperturbed backscatter subcarrier, but also a perturbed backscatter subcarrier. There are a total of L backscatter subcarriers, and l ≤ L. can be characterized as the channel coefficient of the channel for transmitting the \(l\)-th subcarrier of the \(i\)-th frequency-shifted signal under the \(n\)-th data segment. \(x(i, l', n)\) can be characterized as the \(l'\)-th excitation subcarrier in the excitation signal corresponding to the \(l\)-th subcarrier of the \(i\)-th frequency-shifted signal under the \(n\)-th data segment. Among them, the receiver receives a total of \(I\) frequency-shifted signals. However, only the subcarriers in the data segment of the first frequency-shifted signal completely correspond to the subcarriers in the excitation signal, and the subcarriers in the data segments of the remaining \(N - 1\) frequency-shifted signals correspond to a certain subcarrier in the excitation signal under preset conditions. For example, the receiver receives a total of 4 frequency-shifted signals, and the preset rule is that the excitation subcarriers in the excitation signal corresponding to the subcarriers in the data segment of each frequency-shifted signal differ by 16. Then, the first subcarrier in the data segment of the first frequency-shifted signal corresponds to the first excitation subcarrier in the excitation signal, that is, the first to the 64th subcarriers in the data segment of the first frequency-shifted signal correspond to the first to the 64th excitation subcarriers in the excitation signal. The first subcarrier in the data segment of the second frequency-shifted signal corresponds to the 17th excitation subcarrier in the excitation signal, that is, the 64 subcarriers in the data segment of the second frequency-shifted signal correspond to the 17th to the 64th excitation subcarriers in the excitation signal. The first subcarrier in the data segment of the third frequency-shifted signal corresponds to the 33rd excitation subcarrier in the excitation signal, that is, the 64 subcarriers in the data segment of the third frequency-shifted signal correspond to the 33rd to the 64th excitation subcarriers in the excitation signal. The first subcarrier in the data segment of the fourth frequency-shifted signal corresponds to the 49th excitation subcarrier in the excitation signal, that is, the 64 subcarriers in the data segment of the fourth frequency-shifted signal correspond to the 49th to the 64th excitation subcarriers in the excitation signal. \(j\) can be characterized as the complex conjugate. can be characterized as the phase error of the frequency-shifted signal corresponding to the \(l\)-th subcarrier of the \(i\)-th frequency-shifted signal under the \(n\)-th data segment.

[0189] According to an embodiment of the present disclosure, the second spectrum is eliminated in the first spectrum to obtain a target spectrum.

[0190] According to an embodiment of the present disclosure, the target spectrum can be characterized as a spectrum that does not contain the spectrum of the target frequency-shifted signal.

[0191] According to an embodiment of the present disclosure, the target spectrum can be calculated according to formula (8), and formula (8) is shown as follows.

[0192]

[0193] Among them, \(S(i + 1, l, n)\) can be characterized as the spectrum that does not contain the spectrum of the \(i\)-th frequency-shifted signal, that is, the target spectrum, and \(S(i, l, n)\) can be characterized as the spectrum that contains the spectra of the first to the \(i\)-th frequency-shifted signals, that is, the first spectrum.

[0194] According to an embodiment of the present disclosure, the processes of fitting the first phase error corresponding to the first subcarrier, performing quadratic linear fitting on the first offset frequency, and eliminating the second spectrum in the first spectrum can be collectively referred to as interference cancellation of the frequency-shifted signal.

[0195] According to an embodiment of the present disclosure, the receiver can process all the received frequency-shifted signals according to the above processes, so as to obtain the spectrum containing only each frequency-shifted signal, and can perform subsequent processing on each frequency-shifted signal.

[0196] According to an embodiment of the present disclosure, since the second spectrum is obtained according to the excitation signal, the channel coefficient, the phase of the square wave signal corresponding to the first subcarrier, and the second phase error corresponding to the second subcarrier, and then the second spectrum is eliminated in the first spectrum to obtain the target spectrum, the demodulated frequency-shifted signal is eliminated in the spectrum, so that the frequency-shifted signal can be transmitted in a channel with interference. After the receiver receives multiple frequency-shifted signals, the multiple frequency-shifted signals are processed to demodulate each non-interfered frequency-shifted signal, further improving the throughput of the system.

[0197] Figure 5 A schematic diagram schematically shows the packet structure of the backscatter device according to an embodiment of the present disclosure.

[0198] As Figure 5 shown, in the embodiment, the packet structure of the backscatter device is shown. In the packet structure, 501 can be characterized as an environmental signal packet, and the environmental signal packet can be characterized as an excitation signal. 502 can be characterized as a square wave signal packet, and the square wave signal packet can be characterized as multiple square wave signals generated by the backscatter device. 503 can be characterized as a frequency-shifted signal. The excitation signal includes a sequence signal segment and a data signal segment. The data signal segment includes multiple excitation signal segments with signal data. The square wave signal includes a sequence signal segment, a reference signal segment, and a data signal segment. Among the multiple square wave signals, the backscatter device used to generate the first square wave signal is set as the leading device. Only the sequence of the square wave signal generated by the leading device has a preamble. On the reference signal segment, each square wave signal has two data segments with tag data. The tag data can be 0 or 1. The two data segments of each square wave signal are staggered from each other and do not overlap. The frequency-shifted signal includes a sequence signal segment, a reference signal segment, and a data signal segment. The data signal segment includes multiple frequency-shifted signal segments. When a large number of frequency-shifted signals are transmitted concurrently, the multiple frequency-shifted signal segments in the frequency-shifted signals received by the receiver will overlap with each other.

[0199] Figure 6 A schematic diagram schematically shows the phase of the original frequency-shifted signal corresponding to the frequency-shifted signal in the case of interference according to an embodiment of the present disclosure.

[0200] AsFigure 6 As shown, in the embodiment, the phase of the original frequency-shifted signal corresponding to the data segment of the frequency-shifted signal under interference is shown. The abscissa can be characterized as the in-phase component, and the ordinate can be characterized as the quadrature component. In the presence of interference, due to the interference causing the phase of the square wave signal to shift, it can be seen that the phase of the original frequency-shifted signal is arbitrarily distributed.

[0201] Figure 7 Schematically shown is a schematic diagram of the original frequency-shifted signal after recursion under interference according to an embodiment of the present disclosure.

[0202] As Figure 7 shown, in the embodiment, the distribution of the original frequency-shifted signal after recursion under interference is shown. The abscissa can be characterized as the in-phase component, and the ordinate can be characterized as the quadrature component. After the recursive processing of the original frequency-shifted signal, it can be seen that most of the frequency-shifted signals are concentratedly distributed at the in-phase component of -1 and the in-phase component of 1, and a small number of square wave signals are scattered.

[0203] Figure 8 Schematically shown is a schematic diagram of the linearly fitted original frequency-shifted signal after recursion under interference according to an embodiment of the present disclosure.

[0204] As Figure 8 shown, in the embodiment, the phase error of the linearly fitted original frequency-shifted signal after recursion under interference is shown. The abscissa can be characterized as the in-phase component, and the ordinate can be characterized as the quadrature component. After the linear fitting of the original frequency-shifted signal after recursive processing, it can be seen that all the frequency-shifted signals are concentratedly distributed at the in-phase component of -1 and the in-phase component of 1.

[0205] Figure 9 Schematically shown is a schematic diagram of the frequency-shifted signal without interference elimination according to an embodiment of the present disclosure.

[0206] As Figure 9 shown, in the embodiment, the frequency-shifted signal without interference elimination is shown. The abscissa can be characterized as time, and the ordinate can be characterized as frequency. It can be seen from the figure that there are a total of two frequency-shifted signals in the spectrum. 901 can be characterized as the first frequency-shifted signal with the entire spectrum covered, and 902 can be characterized as the second frequency-shifted signal with the spectrum not covered. After the receiver receives the two frequency-shifted signals, it cannot obtain the first frequency-shifted signal, and thus cannot perform subsequent operations on the first frequency-shifted signal. In order to avoid the receiver receiving the frequency-shifted signal with the covered spectrum, it is necessary to select a channel that will not be interfered with for transmission, resulting in a reduction in the throughput of the system.

[0207] Figure 10A schematic diagram showing a frequency-shifted signal with interference cancellation according to an embodiment of the present disclosure is shown.

[0208] As Figure 10 shown, in the embodiment, a frequency-shifted signal with interference cancellation is shown. The abscissa can be characterized as time, and the ordinate can be characterized as frequency. It can be seen from the figure that there is now only one frequency-shifted signal in the spectrum. 1001 can be characterized as the first frequency-shifted signal obtained after canceling the second frequency-shifted signal by the method of the present application. At this time, the spectrum of the first frequency-shifted signal is not covered, enabling the receiver to receive multiple frequency-shifted signals simultaneously, and the frequency-shifted signals can be transmitted through an interfering channel, improving the throughput of the system.

[0209] Figure 11 A schematic diagram showing a system architecture according to an embodiment of the present disclosure is shown.

[0210] As Figure 11As shown, the system architecture is illustrated in the embodiment. First, S1101 is the excitation signal, which is emitted by the excitation source. Second, S1102 is the multi-tag signal, which can be characterized as multiple frequency-shifted signals emitted by the backscatter device. The backscatter device sends the multiple frequency-shifted signals to the receiver. Then, S1103 is the preamble function recovery. The receiver first performs preamble function recovery on the received frequency-shifted signals. In the preamble function recovery, the receiver performs frame edge detection on the received frequency-shifted signals, and then estimates the channel coefficient of the channel used to transmit the frequency-shifted signals based on the received frequency-shifted signals. The channel coefficient is the channel parameter. Then, S1104 subcarrier-level demodulation is performed in the receiver. Subcarrier-level demodulation can be characterized as reconstructing the undisturbed subcarriers in the frequency-shifted signals using the channel coefficient to obtain the phase of the square wave signal corresponding to the undisturbed subcarriers and the phase error of the frequency-shifted signals. In subcarrier-level demodulation, the maximum likelihood estimation method is used to calculate the phase of the reconstructed undisturbed subcarriers and the square wave signal corresponding to the undisturbed subcarriers, obtaining the phase of the square wave signal corresponding to the undisturbed subcarriers and the phase error of the frequency-shifted signals corresponding to the undisturbed subcarriers. Finally, S1105 tag signal reconstruction and interference cancellation are performed in the receiver. The phase error of the frequency-shifted signals corresponding to the interfered subcarriers is calculated using the phase error of the frequency-shifted signals corresponding to the clean subcarriers obtained in S1104, and then the spectrum is reconstructed. The frequency-shifted signals of the undisturbed subcarriers are eliminated from the spectrum, obtaining the interference-canceled signal S1106. From the frequency-shifted signals in S1102 and the interference-canceled signal S1106, it can be seen that the outermost frequency-shifted signal in S1102, that is, the target frequency-shifted signal whose spectrum completely covers other frequency-shifted signals, is eliminated, and the first subcarrier of the signal whose spectrum is covered is exposed in the reconstructed spectrum. Further, the receiver can demodulate the frequency-shifted signals whose spectra are completely covered based on the exposed first subcarriers.

[0211] Figure 12 Schematically shows a flowchart of a wireless network backscattering method supporting multi-tag concurrency applied to a backscatter device according to an embodiment of the present disclosure.

[0212] As Figure 12 shown, the wireless network backscattering method supporting multi-tag concurrency applied to the backscatter device in this embodiment includes operation S1210 to operation S1220.

[0213] In operation S1210, in response to the received excitation signal, a frequency-shifted signal is generated according to the excitation signal and the square wave signal.

[0214] According to an embodiment of the present disclosure, after the backscatter device receives the excitation signal from the excitation source, the excitation signal is multiplied by the square wave signal to obtain the frequency-shifted signal.

[0215] According to an embodiment of the present disclosure, a plurality of excitation signal segments are included in the excitation signal. In the backscatter device, the excitation signal segments of the excitation signal are modulated so that the excitation signal segments carry signal data 0 or signal data 1.

[0216] According to an embodiment of the present disclosure, after the signal segments of the excitation signal are modulated, according to the data on the signal segments of the excitation signal, a frequency-shifted signal is obtained by multiplying it with square wave signals of different phases.

[0217] According to an embodiment of the present disclosure, the data on the excitation signal segments of the excitation signal corresponds to different phases. Signal data 0 corresponds to a square wave signal with a phase of 0, and signal data 1 corresponds to a square wave signal with a phase of π.

[0218] According to an embodiment of the present disclosure, multiplying the signal segment of the excitation signal with a signal data of 0 by a square wave signal with a phase of 0 causes a phase shift of 0 in the obtained signal segment of the excitation signal.

[0219] According to an embodiment of the present disclosure, multiplying the signal segment of the excitation signal with a signal data of 1 by a square wave signal with a phase of π causes a phase shift of π in the obtained signal segment of the excitation signal.

[0220] According to an embodiment of the present disclosure, in the packet structure of the backscatter device, corresponding square wave signals are generated at corresponding times.

[0221] According to an embodiment of the present disclosure, tag data is added to the data segment of the square wave signal. The tag data can be tag data 0 or tag data 1.

[0222] According to an embodiment of the present disclosure, tag data 0 on the data segment of the square wave signal corresponds to a phase of 0 of the square wave signal, and tag data 1 on the data segment of the square wave signal corresponds to a phase of π of the square wave signal.

[0223] According to an embodiment of the present disclosure, a reference field is generated based on the unperturbed backscattered subcarriers on the generated frequency-shifted signal.

[0224] In operation S1220, the frequency-shifted signal and the reference field are sent to the receiver.

[0225] According to an embodiment of the present disclosure, a reference field is used to characterize subcarriers in a frequency-shifted signal whose spectrum is not covered. The frequency-shifted signal includes a first subcarrier and a second subcarrier, so that a receiver can use the reference field to process the frequency domain of the frequency-shifted signal to obtain a channel coefficient. The frequency domain is obtained by processing the time domain of the frequency-shifted signal using a Fourier transform. According to the first subcarrier and the channel coefficient, a target phase error corresponding to the first subcarrier is obtained; according to the target phase error corresponding to the first subcarrier and the frequency offset of the second subcarrier relative to a predetermined subcarrier, a target phase error corresponding to the second subcarrier is obtained; according to the second phase error corresponding to the second subcarrier, the first spectrum is adjusted to obtain a target spectrum.

[0226] According to an embodiment of the present disclosure, since a frequency-shifted signal is generated according to a received excitation signal and a square-wave signal, and then the frequency-shifted signal and the reference field are sent to a receiver, processing of the frequency-shifted signal in a backscatter device is realized to protect the preamble of the frequency-shifted signal from being damaged during transmission, so that the receiver can accurately calculate the channel coefficient of the channel used for transmission after receiving the frequency-shifted signal.

[0227] Figure 13 Schematically shows a structural block diagram of a wireless network backscatter device supporting multi-tag concurrency applied to a receiver according to an embodiment of the present disclosure.

[0228] As Figure 13 shown, the backscatter device supporting multi-tag concurrency applied to a receiver in this embodiment includes a processing module 1310, a first obtaining module 1320, a second obtaining module 1330, and an adjustment module 1340.

[0229] The processing module 1310 is configured to, in response to a received frequency-shifted signal and a reference field, process the frequency domain of the frequency-shifted signal using the reference field to obtain a channel coefficient, where the frequency domain is obtained by processing the time domain of the frequency-shifted signal using a Fourier transform; the reference field is used to characterize subcarriers in the frequency-shifted signal whose spectrum is not covered, and the frequency-shifted signal includes a first subcarrier and a second subcarrier. The processing module 1310 can be used to perform the operation S210 described above, which will not be elaborated here.

[0230] The first obtaining module 1320 is configured to obtain a first phase error corresponding to the first subcarrier according to the first subcarrier and the channel coefficient. The first obtaining module 1320 can be used to perform the operation S220 described above, which will not be elaborated here.

[0231] A second obtaining module 1330, configured to obtain a second phase error corresponding to a second subcarrier according to a first phase error corresponding to a first subcarrier and a second offset frequency of the second subcarrier relative to a predetermined subcarrier. The second obtaining module 1330 may be configured to perform the operation S230 described above, which will not be elaborated herein.

[0232] An adjustment module 1340, configured to adjust a first spectrum according to the second phase error corresponding to the second subcarrier to obtain a target spectrum, where the first spectrum is obtained by processing a frequency-shifted signal using a Fourier transform. The adjustment module 1340 may be configured to perform the operation S240 described above, which will not be elaborated herein.

[0233] According to an embodiment of the present disclosure, the processing module 1310 includes: a first processing sub-module and a second processing sub-module.

[0234] The first processing sub-module is configured to process the time domain of the frequency-shifted signal to obtain a frequency domain corresponding to the time domain of the frequency-shifted signal.

[0235] The second processing sub-module is configured to process the frequency domain corresponding to the time domain of the frequency-shifted signal using a reference field to obtain a channel coefficient.

[0236] According to an embodiment of the present disclosure, the first obtaining module 1320 includes: a first obtaining sub-module, a second obtaining sub-module, and a third obtaining sub-module.

[0237] The first obtaining sub-module is configured to obtain a first excitation subcarrier corresponding to the first subcarrier from an excitation signal according to the first subcarrier.

[0238] The second obtaining sub-module is configured to obtain a first reconstructed subcarrier according to the channel coefficient and the first excitation subcarrier.

[0239] The third obtaining sub-module is configured to obtain a first phase error corresponding to the first subcarrier according to the first reconstructed subcarrier.

[0240] According to an embodiment of the present disclosure, the third obtaining sub-module includes: a first calculation unit, a first acquisition unit, a first obtaining unit, and a second obtaining unit.

[0241] The first calculation unit is configured to perform a calculation on the first reconstructed subcarrier corresponding to the nth data segment to obtain a phase of a square wave signal corresponding to the first subcarrier in the nth data segment.

[0242] The first acquisition unit is configured to acquire a phase error of the first subcarrier corresponding to the (n - 1)th data segment for the first subcarrier corresponding to the nth data segment.

[0243] A first obtaining unit, configured to obtain a first initial phase error corresponding to a first subcarrier in the nth data segment according to a phase error of a first subcarrier corresponding to an (n - 1)th data segment and a phase of a square wave signal corresponding to the first subcarrier in the nth data segment.

[0244] A second obtaining unit, configured to perform linear fitting on the first initial phase error corresponding to the first subcarrier in the nth data segment to obtain a first phase error corresponding to the first subcarrier in the nth data segment.

[0245] According to an embodiment of the present disclosure, the second obtaining unit includes: a first fitting subunit, a first confirmation subunit, and a second confirmation subunit.

[0246] The first fitting subunit is configured to perform linear fitting on the first initial phase error corresponding to the first subcarrier in the nth data segment by using fitting parameters to obtain a first linearly fitted phase error corresponding to the first subcarrier in the nth data segment.

[0247] The first confirmation subunit is configured to confirm that the first initial phase error corresponding to the first subcarrier is the first phase error of the first subcarrier in the nth data segment when a difference between the first linearly fitted phase error corresponding to the first subcarrier in the nth data segment and the first initial phase error corresponding to the first subcarrier in the nth data segment is less than or equal to a predetermined error threshold.

[0248] The second confirmation subunit is configured to confirm that the first linearly fitted phase error corresponding to the first subcarrier is the first phase error of the first subcarrier in the nth data segment when a difference between the first linearly fitted phase error corresponding to the first subcarrier in the nth data segment and the first initial phase error corresponding to the first subcarrier in the nth data segment is greater than the predetermined error threshold.

[0249] According to an embodiment of the present disclosure, the second obtaining module 1330 includes: a first fitting submodule, a second fitting submodule, and a fourth obtaining submodule.

[0250] The first fitting submodule is configured to perform linear fitting on the first phase error corresponding to the first subcarrier to obtain a first offset frequency of the first subcarrier relative to a predetermined subcarrier, where the offset frequency is a fitting slope obtained by linear fitting.

[0251] The second fitting submodule is configured to perform quadratic linear fitting on the first offset frequency of the first subcarrier relative to the predetermined subcarrier to obtain a second offset frequency of a second subcarrier relative to the predetermined subcarrier.

[0252] The fourth obtaining submodule is configured to obtain a second phase error corresponding to the second subcarrier according to the second offset frequency of the second subcarrier relative to the predetermined subcarrier and the first phase error corresponding to the first subcarrier.

[0253] According to an embodiment of the present disclosure, the adjustment module 1340 includes: a fifth obtaining sub-module and a first eliminating sub-module.

[0254] The fifth obtaining sub-module is configured to obtain a second spectrum according to an excitation signal, a channel coefficient, a phase of a square wave signal corresponding to a first sub-carrier, and a second phase error corresponding to a second sub-carrier.

[0255] The first eliminating sub-module is configured to eliminate the second spectrum from the first spectrum to obtain a target spectrum.

[0256] According to an embodiment of the present disclosure, any plurality of the processing module 1310, the first obtaining module 1320, the second obtaining module 1330, and the adjustment module 1340 may be combined and implemented in one module, or any one of them may be split into multiple modules. Alternatively, at least part of the functions of one or more of these modules may be combined with at least part of the functions of other modules and implemented in one module. According to an embodiment of the present disclosure, at least one of the processing module 1310, the first obtaining module 1320, the second obtaining module 1330, and the adjustment module 1340 may be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on chip, a system on substrate, a system on package, an application specific integrated circuit (ASIC), or any other reasonable way of integrating or packaging circuits, etc., implemented by hardware or firmware, or implemented in any one of the three implementation manners of software, hardware, and firmware, or in an appropriate combination of any several of them. Alternatively, at least one of the processing module 1310, the first obtaining module 1320, the second obtaining module 1330, and the adjustment module 1340 may be at least partially implemented as a computer program module, and when the computer program module is run, it can execute the corresponding functions.

[0257] Figure 14 Schematically shows a structural block diagram of a wireless network backscatter device supporting multi-tag concurrency applied to a backscatter device according to an embodiment of the present disclosure.

[0258] As Figure 14 shown, the wireless network backscatter device supporting multi-tag concurrency applied to a receiver in this embodiment includes a generating module 1410 and a transmitting module 1420.

[0259] The generating module 1410 is configured to generate a frequency-shifted signal according to an excitation signal and a square wave signal in response to the received excitation signal, where the excitation signal is sent by an excitation source to the backscatter device, and the generating module 1410 may be used to perform the operation S2120 described above, which will not be elaborated here.

[0260] A transmitting module 1420 is configured to transmit a frequency-shifted signal and a reference field to a receiver. The reference field is used to characterize sub-carriers in the frequency-shifted signal that are not covered by the spectrum. The frequency-shifted signal includes a first sub-carrier and a second sub-carrier, so that the receiver can use the reference field to process the frequency domain of the frequency-shifted signal to obtain a channel coefficient. The frequency domain is obtained by processing the time domain of the frequency-shifted signal using a Fourier transform. Based on the first sub-carrier and the channel coefficient, a first phase error corresponding to the first sub-carrier is obtained; based on the first phase error corresponding to the first sub-carrier and a second offset frequency of the second sub-carrier relative to a predetermined sub-carrier, a second phase error corresponding to the second sub-carrier is obtained; and based on the second phase error corresponding to the second sub-carrier, a first spectrum is adjusted to obtain a target spectrum. The transmitting module 1420 can be configured to perform the operation S1220 described above, which will not be elaborated here.

[0261] According to an embodiment of the present disclosure, any plurality of the generating module 1410 and the transmitting module 1420 can be combined and implemented in one module, or any one of them can be split into multiple modules. Alternatively, at least part of the functions of one or more of these modules can be combined with at least part of the functions of other modules and implemented in one module. According to an embodiment of the present disclosure, at least one of the generating module 1410 and the transmitting module 1420 can be at least partially implemented as a hardware circuit, such as a field-programmable gate array (FPGA), a programmable logic array (PLA), a system on a chip, a system on a substrate, a system on a package, an application-specific integrated circuit (ASIC), or any other reasonable way of integrating or packaging circuits, etc., implemented by hardware or firmware, or implemented in any one of the three implementation manners of software, hardware, and firmware, or in an appropriate combination of any several of them. Alternatively, at least one of the generating module 1410 and the transmitting module 1420 can be at least partially implemented as a computer program module, which can perform corresponding functions when the computer program module is run.

[0262] Figure 15 A block diagram of an electronic device suitable for supporting a wireless network backscattering method for multi-tag concurrency according to an embodiment of the present disclosure is schematically shown.

[0263] As Figure 15As shown, the electronic device according to an embodiment of the present disclosure includes a processor 1501, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1502 or a program loaded from a storage section 1508 into a random access memory (RAM) 1503. The processor 1501 can include, for example, a general microprocessor (such as a CPU), an instruction set processor, and / or a related chipset, and / or a dedicated microprocessor (such as an application-specific integrated circuit (ASIC)), etc. The processor 1501 can also include on-board memory for caching purposes. The processor 1501 can include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present disclosure.

[0264] In the RAM 1503, various programs and data required for the operation of the electronic device are stored. The processor 1501, the ROM 1502, and the RAM 1503 are connected to each other via a bus 1504. The processor 1501 performs various operations of the method flow according to an embodiment of the present disclosure by executing the program in the ROM 1502 and / or the RAM 1503. It should be noted that the program can also be stored in one or more memories other than the ROM 1502 and the RAM 1503. The processor 1501 can also perform various operations of the method flow according to an embodiment of the present disclosure by executing the program stored in the one or more memories.

[0265] According to an embodiment of the present disclosure, the electronic device may further include an input / output (I / O) interface 1505, and the input / output (I / O) interface 1505 is also connected to the bus 1504. The electronic device 1500 may further include one or more of the following components connected to the I / O interface 1505: an input section 1506 including a keyboard, a mouse, etc.; an output section 1507 including, for example, a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 1508 including a hard disk, etc.; and a communication section 1509 including a network interface card such as a LAN card, a modem, etc. The communication section 1509 performs communication processing via a network such as the Internet. A drive 1510 is also connected to the I / O interface 1505 as needed. A removable medium 1511, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 1510 as needed so that a computer program read from it can be installed into the storage section 1508 as needed.

[0266] The present disclosure also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the foregoing embodiments; or may exist separately without being assembled into the device / apparatus / system. The foregoing computer-readable storage medium carries one or more programs, and when the one or more programs are executed, the methods according to the embodiments of the present disclosure are implemented.

[0267] According to an embodiment of the present disclosure, the computer-readable storage medium may be a non-volatile computer-readable storage medium, and for example, may include but is not limited to: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing. In the present disclosure, the computer-readable storage medium may be any tangible medium that contains or stores a program, and the program may be used by or in conjunction with an instruction execution system, apparatus, or device. For example, according to an embodiment of the present disclosure, the computer-readable storage medium may include the ROM 1502 and / or the RAM 1503 described above and / or one or more memories other than the ROM 1502 and the RAM 1503.

[0268] An embodiment of the present disclosure further includes a computer program product, which includes a computer program, and the computer program includes program code for executing the method shown in the flowchart. When the computer program product runs in a computer system, the program code is used to cause the computer system to implement the item recommendation method provided by the embodiments of the present disclosure.

[0269] When the computer program is executed by the processor 1501, the above functions defined in the system / apparatus of the embodiments of the present disclosure are executed. According to an embodiment of the present disclosure, the foregoing systems, apparatuses, modules, units, etc. may be implemented by computer program modules.

[0270] In one embodiment, the computer program may rely on tangible storage media such as optical storage devices and magnetic storage devices. In another embodiment, the computer program may also be transmitted and distributed in the form of a signal on a network medium, and is downloaded and installed through the communication part 1509, and / or installed from the removable medium 1511. The program code included in the computer program may be transmitted by any suitable network medium, including but not limited to: wireless, wired, etc., or any suitable combination of the foregoing.

[0271] In such an embodiment, the computer program can be downloaded and installed from a network through the communication section 1509, and / or installed from the removable medium 1511. When the computer program is executed by the processor 1501, the above-described functions defined in the system of the embodiments of the present disclosure are performed. According to the embodiments of the present disclosure, the above-described systems, devices, apparatuses, modules, units, etc. can be implemented by computer program modules.

[0272] According to the embodiments of the present disclosure, the program code for executing the computer program provided by the embodiments of the present disclosure can be written in any combination of one or more programming languages. Specifically, these computing programs can be implemented using high-level procedures and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages include, but are not limited to, such as Java, C++, python, "C" language or similar programming languages. The program code can be executed entirely on the user computing device, partially on the user device, partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device can be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computing device (e.g., by connecting through the Internet using an Internet service provider).

[0273] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagram may represent a module, a program segment, or a part of the code, and the above-mentioned module, program segment, or part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than marked in the accompanying drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram or flowchart, and the combination of blocks in the block diagram or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions.

[0274] Those skilled in the art can understand that the features recited in the various embodiments and / or claims of the present disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly recited in the present disclosure. In particular, without departing from the spirit and teachings of the present disclosure, the features recited in the various embodiments and / or claims of the present disclosure can be combined and combined in various ways. All such combinations and / or combinations fall within the scope of the present disclosure.

[0275] The embodiments of the present disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although the embodiments have been described separately above, this does not mean that the measures in each embodiment cannot be used advantageously in combination. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, and all such substitutions and modifications should fall within the scope of the present disclosure.

Claims

1. A wireless backscattering method supporting multi - tag concurrency, applied to a receiver, includes: In response to a received frequency - shifted signal and a reference field, processing the frequency domain of the frequency - shifted signal by using the reference field to obtain a channel coefficient, where the frequency domain is obtained by processing the time domain of the frequency - shifted signal using Fourier transform, the reference field is used to characterize sub - carriers in the frequency - shifted signal whose spectrum is not covered, and the frequency - shifted signal includes the first sub - carrier and the second sub - carrier; According to the first sub - carrier and the channel coefficient, obtaining a first phase error corresponding to the first sub - carrier; According to the first phase error corresponding to the first sub - carrier and a second offset frequency of the second sub - carrier relative to a predetermined sub - carrier, obtaining a second phase error corresponding to the second sub - carrier; Adjusting a first spectrum according to the second phase error corresponding to the second sub - carrier to obtain a target spectrum, where the first spectrum is obtained by processing the frequency - shifted signal using Fourier transform.

2. The method according to claim 1, wherein, The step of, in response to a received frequency - shifted signal and a reference field, processing the frequency domain of the frequency - shifted signal by using the reference field to obtain a channel coefficient includes: Processing the time domain of the frequency - shifted signal to obtain a frequency domain corresponding to the time domain of the frequency - shifted signal; Processing the frequency domain corresponding to the time domain of the frequency - shifted signal by using the reference field to obtain a channel coefficient.

3. The method according to claim 1, wherein, The step of, according to the first sub - carrier and the channel coefficient, obtaining a first phase error corresponding to the first sub - carrier includes: According to the first sub - carrier, obtaining a first excitation sub - carrier corresponding to the first sub - carrier from an excitation signal; According to the channel coefficient and the first excitation sub - carrier, obtaining a first reconstructed sub - carrier; According to the first reconstructed sub - carrier, obtaining a first phase error corresponding to the first sub - carrier.

4. The method according to claim 3, wherein, The frequency - shifted signal includes a square - wave signal, and in the data signal segment of the square - wave signal, there are N data segments, N is an integer greater than 1, n is an integer greater than 1, and n ≤ N. The step of, according to the first reconstructed sub - carrier, obtaining a first phase error corresponding to the first sub - carrier includes: For the nth data segment, calculating the first reconstructed sub - carrier corresponding to the nth data segment to obtain the phase of the square - wave signal corresponding to the first sub - carrier in the nth data segment; For the first sub - carrier corresponding to the nth data segment, obtaining the phase error of the first sub - carrier corresponding to the (n - 1)th data segment; According to the phase error of the first sub - carrier corresponding to the (n - 1)th data segment and the phase of the square - wave signal corresponding to the first sub - carrier in the nth data segment, obtaining a first initial phase error corresponding to the first sub - carrier in the nth data segment; Performing linear fitting on the first initial phase error corresponding to the first sub - carrier in the nth data segment to obtain a first phase error corresponding to the first sub - carrier in the nth data segment.

5. The method according to claim 4, wherein Performing linear fitting on the first initial phase error corresponding to the first subcarrier in the nth data segment to obtain the first phase error corresponding to the first subcarrier in the nth data segment includes: Using the fitting parameters to perform linear fitting on the first initial phase error corresponding to the first subcarrier in the nth data segment to obtain the first linearly fitted phase error corresponding to the first subcarrier in the nth data segment; When the difference between the first linearly fitted phase error corresponding to the first subcarrier in the nth data segment and the first initial phase error corresponding to the first subcarrier in the nth data segment is less than or equal to a predetermined error threshold, confirming that the first initial phase error corresponding to the first subcarrier is the first phase error of the first subcarrier in the nth data segment; When the difference between the first linearly fitted phase error corresponding to the first subcarrier in the nth data segment and the first initial phase error corresponding to the first subcarrier in the nth data segment is greater than the predetermined error threshold, confirming that the first linearly fitted phase error corresponding to the first subcarrier is the first phase error of the first subcarrier in the nth data segment.

6. The method according to claim 1, wherein Obtaining the second phase error corresponding to the second subcarrier according to the first phase error corresponding to the first subcarrier and the first offset frequency of the second subcarrier relative to a predetermined subcarrier includes: Performing linear fitting on the first phase error corresponding to the first subcarrier to obtain the first offset frequency of the first subcarrier relative to the predetermined subcarrier, where the offset frequency is the fitting slope obtained by linear fitting; Performing quadratic linear fitting on the first offset frequency of the first subcarrier relative to the predetermined subcarrier to obtain the second offset frequency of the second subcarrier relative to the predetermined subcarrier; Obtaining the second phase error corresponding to the second subcarrier according to the second offset frequency of the second subcarrier relative to the predetermined subcarrier and the first phase error corresponding to the first subcarrier.

7. The method according to claim 1, wherein Adjusting the first spectrum according to the second phase error corresponding to the second subcarrier to obtain the target spectrum includes: Obtaining a second spectrum according to the excitation signal, the channel coefficient, the phase of the square wave signal corresponding to the first subcarrier, and the second phase error corresponding to the second subcarrier; Eliminating the second spectrum from the first spectrum to obtain the target spectrum.

8. A wireless network backscattering method supporting multi-tag concurrency, applied to a backscattering device, includes: Responding to the received excitation signal, generating a frequency-shifted signal according to the excitation signal and the square wave signal, where the excitation signal is sent by an excitation source to the backscattering device; Send the frequency-shifted signal and the reference field to a receiver, where the reference field is used to characterize subcarriers in the frequency-shifted signal whose spectra are not covered. The frequency-shifted signal includes the first subcarrier and the second subcarrier, so that the receiver can use the reference field to process the frequency domain of the frequency-shifted signal to obtain a channel coefficient. The frequency domain is obtained by processing the time domain of the frequency-shifted signal using a Fourier transform. According to the first subcarrier and the channel coefficient, a first phase error corresponding to the first subcarrier is obtained; according to the first phase error corresponding to the first subcarrier and a second offset frequency of the second subcarrier relative to a predetermined subcarrier, a second phase error corresponding to the second subcarrier is obtained; and according to the second phase error corresponding to the second subcarrier, a first spectrum is adjusted to obtain a target spectrum.

9. A wireless backscatter device supporting multi-tag concurrency, applied to a receiver, includes: A processing module, configured to, in response to receiving a frequency-shifted signal and a reference field, process the frequency domain of the frequency-shifted signal using the reference field to obtain a channel coefficient, where the frequency domain is obtained by processing the time domain of the frequency-shifted signal using a Fourier transform; the reference field is used to characterize subcarriers in the frequency-shifted signal whose spectra are not covered, and the frequency-shifted signal includes the first subcarrier and the second subcarrier; A first obtaining module, configured to obtain a first phase error corresponding to the first subcarrier according to the first subcarrier and the channel coefficient; A second obtaining module, configured to obtain a second phase error corresponding to the second subcarrier according to the first phase error corresponding to the first subcarrier and a second offset frequency of the second subcarrier relative to a predetermined subcarrier; An adjustment module, configured to adjust a first spectrum according to the second phase error corresponding to the second subcarrier to obtain a target spectrum, where the first spectrum is obtained by processing the frequency-shifted signal using a Fourier transform.

10. A wireless backscatter device supporting multi-tag concurrency, applied to a backscatter device, includes: A generating module, configured to, in response to receiving an excitation signal, generate a frequency-shifted signal according to the excitation signal and a square wave signal, where the excitation signal is sent by an excitation source to the backscatter device; A transmitting module, configured to transmit the frequency-shifted signal and a reference field to a receiver, wherein the reference field is used to characterize sub-carriers in the frequency-shifted signal that are not covered by the spectrum, the frequency-shifted signal includes the first sub-carrier and the second sub-carrier, so that the receiver can use the reference field to process the frequency domain of the frequency-shifted signal to obtain a channel coefficient, the frequency domain is obtained by processing the time domain of the frequency-shifted signal using Fourier transform, a first phase error corresponding to the first sub-carrier is obtained according to the first sub-carrier and the channel coefficient; a second phase error corresponding to the second sub-carrier is obtained according to the first phase error corresponding to the first sub-carrier and a second offset frequency of the second sub-carrier relative to a predetermined sub-carrier; a first spectrum is adjusted according to the second phase error corresponding to the second sub-carrier to obtain a target spectrum.

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