Backscatter Internet of Things system, communication method, device, network equipment and medium

Abstract

The present disclosure provides a backscattering Internet of Things system, communication method, device, network equipment and medium, which relate to the field of Internet of Things technology. Among them, the backscattering Internet of Things system includes: a main transmitter for sending downlink signals; multiple backscattering devices for orthogonally modulating the received downlink signals to generate multiple backscattering signals, and sending multiple backscattering signals in parallel; a receiver for receiving baseband signals based on the main link channel, and receiving multiple backscattering reception signals based on multiple secondary link channels. The receiver is also used to: eliminate interference of the main link channel based on channel estimation operation; and restore the baseband signal and multiple backscattering reception signals based on the coordinated parallel detection operation of the baseband signal and the multiple backscattering reception signals. The technical solution of the present disclosure is conducive to the deployment of multiple backscattering devices in the Internet of Things system.

Description

Technical Field

[0001] The present disclosure relates to the technical field of Internet of Things, and in particular to a backscattering Internet of Things system, a backscattering Internet of Things communication method, a backscattering Internet of Things communication device, a network device, and a computer-readable storage medium. Background Art

[0002] Ambient backscatter communication uses ambient RF signals rather than dedicated carrier signals to implement modulated backscatter communication, thereby achieving ultra-low power consumption, low cost, and long-term sustainability in the construction of a green Internet of Things. However, due to mutual interference between channels, it is difficult to achieve simultaneous access of large-scale devices.

[0003] Although physical isolation, frequency isolation, or time isolation can be used to eliminate inter-channel interference, in complex communication systems, these methods have disadvantages such as a limited number of deployed devices and greater occupation of spectrum resources, making it impossible to achieve parallel and reliable transmission of multiple backscatter devices.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the Invention

[0005] The present disclosure aims to provide a backscattering Internet of Things communication system, method, apparatus, network device, and medium, which, at least to a certain extent, overcome the problem in the related art of the inability of multiple backscattering devices in the backscattering Internet of Things to transmit reliably in parallel.

[0006] Other features and advantages of the present disclosure will become apparent from the following detailed description, or may be learned in part by practice of the present disclosure.

[0007] According to one aspect of the present disclosure, a backscattering Internet of Things communication system is provided, comprising: a main transmitter for sending a downlink signal; a plurality of backscattering devices for performing orthogonal modulation on the received downlink signal to generate a plurality of backscattering signals; the plurality of backscattering devices are further configured to send the plurality of backscattering signals in parallel; a receiver for receiving a baseband signal based on a main link channel, and receiving a plurality of backscattering reception signals based on a plurality of secondary link channels, the baseband signal corresponding to the downlink signal, and the backscattering reception signal corresponding to the backscattering signal; the receiver is further configured to eliminate interference of the main link channel based on a channel estimation operation; the receiver is further configured to recover the baseband signal and the plurality of backscattering reception signals based on a collaborative parallel detection operation of the plurality of backscattering reception signals.

[0008] In one embodiment, the backscattering device is further used to: perform orthogonal coding processing based on the downlink signal to generate an on-off keyed code chip sequence to generate the backscattering signal based on the code chip sequence, and the code chip sequences of multiple backscattering devices constitute a Hadamard orthogonal matrix, and the code chip sequence includes L-bit code chips, wherein the downlink signal has a first frame structure, the first frame structure includes multiple first signal periods, the backscattering signal has a second frame structure, the second frame structure includes multiple second signal periods, the second signal period is L×M times the first signal period, L is the number of code chip bits of the orthogonal coding, and M is the ratio of the code chip period to the first signal period.

[0009] In one embodiment, the receiver is further configured to determine a received joint data signal based on the baseband signal, the backscattered received signal, and Gaussian white noise received within each second signal period of the channel coherence time interval.

[0010] In one embodiment, the primary transmitter is further configured to: transmit a pilot signal at the starting position of a coherence time interval of each link channel, wherein the pilot signal is used to estimate the primary link channel, wherein when the primary transmitter transmits the pilot signal, the backscatter device is in a silent state; the receiver is further configured to: generate a received signal based on the pilot signal; and input the pilot signal and the pilot received signal into a channel estimation model to estimate the primary link channel.

[0011] In one embodiment, the receiver is further used to: perform minimum distance decoding based on the main link channel, the baseband signal and the joint data signal to obtain a source signal; determine the interference signal of the main link channel based on the source signal; eliminate the interference signal from the joint data signal to obtain a corresponding device received signal; and optimize the device received signal based on the reflection coefficient of the backscattering device to obtain an intermediate variable.

[0012] In one embodiment, the backscattered received signal is represented based on a high-level bit and a low-level bit, and the receiver is further used to: calculate a test statistic of the backscattered received signal based on the intermediate variable; perform a maximum likelihood decision on the test statistics corresponding to the high-level bit and the low-level bit based on a collaborative parallel detection operation of the multiple backscattered received signals; and restore the baseband signal and the multiple backscattered received signals based on a decision result of the maximum likelihood decision.

[0013] In one embodiment, the receiver is further used to: obtain all the intermediate variables within a second signal period; perform decoding operations on all the intermediate variables based on a decoding matrix to obtain a test statistic matrix; restore the key test statistic of the backscattered received signal based on the test statistic matrix; determine the cumulative estimation error of the main link channel based on the orthogonality of the backscattered received signal; determine the correspondence between each of the secondary link channels and the corresponding key test statistic based on the cumulative estimation error; adjust the key test statistic based on the correspondence to obtain the test statistic of the backscattered received signal based on the second signal period.

[0014] In one embodiment, the receiver is further used to: determine a first Gaussian distribution of the test statistic under the low-level bit and a second Gaussian distribution of the test statistic under the high-level bit based on the complex Gaussian distribution of the test statistic; construct a first probability density function of the test statistic based on the low-level bit; construct a second probability density function of the test statistic based on the high-level bit; and perform maximum likelihood estimation based on the first probability density function and the second probability density function to estimate a first mean and a second mean of the complex Gaussian distribution.

[0015] In one embodiment, the receiver is further configured to determine an interference cancellation result of the primary link channel on the secondary link channel based on estimation results of the first mean value and the second mean value.

[0016] In one embodiment, the receiver is further used to: construct a statistical decision quantifier for each of the backscatter devices based on the difference between the first mean and the second mean, and the test statistic; construct a decision threshold based on the relationship between the first mean and the second mean; and restore the baseband signal and the multiple backscatter received signals based on the relationship between the statistical decision quantifier and the decision threshold.

[0017] In one embodiment, the receiver is further used to: construct a conditional bit error rate model for each of the secondary link channels based on the relationship between the statistical decision amount and the decision threshold under the low-level bit, and the relationship between the statistical decision amount and the decision threshold under the high-level bit; and calculate the theoretical bit error rate of each of the secondary link channels based on the conditional bit error rate model.

[0018] In one embodiment, the backscatter device includes: an antenna for receiving the downlink signal and transmitting the backscatter signal; a signal modulation module for performing an orthogonal coding modulation operation on the downlink signal to obtain the backscatter signal; a control module for controlling the signal modulation module to perform the modulation operation; and a power supply module for supplying power to the signal modulation module and the control module.

[0019] According to another aspect of the present disclosure, a backscattering Internet of Things communication method is provided, which is applied to a backscattering device, including: receiving a downlink signal sent by a main transmitter; orthogonally modulating the downlink signal to generate a backscattering signal; and sending the backscattering signal.

[0020] In one embodiment, the orthogonal modulation of the downlink signal to generate a backscatter signal includes: performing orthogonal coding processing based on the downlink signal to generate an on-off keyed code chip sequence to generate the backscatter signal based on the code chip sequence, the code chip sequences of multiple backscatter devices constitute a Hadamard orthogonal matrix, and the code chip sequence includes L-bit code chips, wherein the downlink signal has a first frame structure, the first frame structure includes multiple first signal periods, the backscatter signal has a second frame structure, the second frame structure includes multiple second signal periods, the second signal period is L×M times the first signal period, L is the number of code chip bits of the orthogonal coding, and M is the ratio of the code chip period to the first signal period.

[0021] According to another aspect of the present disclosure, a backscattering Internet of Things communication method is provided, which is applied to a receiver, including: receiving a baseband signal based on a main link channel, and receiving multiple backscattered received signals based on multiple secondary link channels, the baseband signal corresponding to a downlink signal of a main transmitter, and the backscattered received signal corresponding to a backscattered signal of a backscattering device; eliminating interference of the main link channel based on a channel estimation operation; and recovering the baseband signal and the multiple backscattered received signals based on a collaborative parallel detection operation.

[0022] In one embodiment, the receiving of a baseband signal based on a main link channel and the receiving of multiple backscattered received signals based on multiple secondary link channels further include: determining a received joint data signal based on the baseband signal, the backscattered received signal and Gaussian white noise received within each second signal period of a channel coherence time interval.

[0023] In one embodiment, the channel estimation-based operation for eliminating interference from the primary link channel includes: acquiring a pilot receive signal of a pilot signal, wherein the pilot signal is sent by a primary transmitter at a starting position of the channel coherence time interval; inputting the pilot signal and the pilot receive signal into a channel estimation model to estimate the primary link channel; and eliminating interference from the primary link channel.

[0024] In one embodiment, the method further includes: constructing the channel estimation model based on a least square estimation model and / or a minimum mean square error estimation model.

[0025] In one embodiment, eliminating interference of the main link channel includes: performing minimum distance decoding based on the main link channel, the baseband signal and the joint data signal to obtain a source signal; determining the interference signal of the main link channel based on the source signal; and eliminating the interference signal from the joint data signal to obtain a corresponding device reception signal.

[0026] In one embodiment, the method further includes: optimizing the device receiving signal based on the reflection coefficient of the backscattering device to obtain an intermediate variable.

[0027] In one embodiment, the backscattered received signal is represented based on a high-level bit and a low-level bit, and the recovering of the baseband signal and the multiple backscattered received signals based on the collaborative parallel detection operation includes: calculating a test statistic of the backscattered received signal based on the intermediate variable; performing a maximum likelihood decision on the test statistics corresponding to the high-level bit and the low-level bit based on the collaborative parallel detection operation of the multiple backscattered received signals; and recovering the baseband signal and the multiple backscattered received signals based on a decision result of the maximum likelihood decision.

[0028] In one embodiment, the calculation of the test statistic of the backscattered received signal based on the intermediate variables includes: obtaining all the intermediate variables within a second signal period; performing decoding operations on all the intermediate variables based on a decoding matrix to obtain a test statistic matrix; restoring the key test statistic of the backscattered received signal based on the test statistic matrix; determining the cumulative estimation error of the main link channel based on the orthogonality of the backscattered received signal; determining the correspondence between each of the secondary link channels and the corresponding key test statistic based on the cumulative estimation error; and adjusting the key test statistic based on the correspondence to obtain the test statistic of the backscattered received signal based on the second signal period.

[0029] In one embodiment, the collaborative parallel detection operation of the multiple backscattered received signals is based on performing maximum likelihood judgment on the test statistics corresponding to the high-level bit and the low-level bit, including: determining a first Gaussian distribution of the test statistic under the low-level bit and a second Gaussian distribution of the test statistic under the high-level bit based on the complex Gaussian distribution of the test statistic; constructing a first probability density function of the test statistic based on the low-level bit; constructing a second probability density function of the test statistic based on the high-level bit; and performing maximum likelihood estimation based on the first probability density function and the second probability density function to estimate a first mean and a second mean of the complex Gaussian distribution.

[0030] In one embodiment, the method further includes: determining an interference cancellation result of the primary link channel on the secondary link channel based on estimation results of the first mean value and the second mean value.

[0031] In one embodiment, the decision result based on the maximum likelihood decision is used to restore the baseband signal and the multiple backscattered received signals, including: constructing a statistical decision amount for each of the backscattered devices based on the difference between the first mean and the second mean, and the test statistic; constructing a decision threshold based on the relationship between the first mean and the second mean; and restoring the baseband signal and the multiple backscattered received signals based on the relationship between the statistical decision amount and the decision threshold.

[0032] In one embodiment, it also includes: constructing a conditional bit error rate model for each of the secondary link channels based on the relationship between the statistical decision amount and the decision threshold under the low-level bit, and the relationship between the statistical decision amount and the decision threshold under the high-level bit; and calculating the theoretical bit error rate of each of the secondary link channels based on the conditional bit error rate model.

[0033] In one embodiment, the method further includes: obtaining a detection bit error rate detected based on an energy detection model; and obtaining detection results of the detection bit error rate and a theoretical bit error rate.

[0034] According to another aspect of the present disclosure, a backscattering Internet of Things communication device is provided, which is applied to a backscattering device and includes: a first receiving module for receiving a downlink signal sent by a main transmitter; a modulation module for orthogonally modulating the downlink signal to generate a backscattering signal; and a sending module for sending the backscattering signal.

[0035] According to another aspect of the present disclosure, a backscattering Internet of Things communication device is provided, which is applied to a receiver and includes: a second receiving module for receiving a baseband signal based on a main link channel, and receiving multiple backscattered received signals based on multiple secondary link channels, the baseband signal corresponding to the downlink signal of the main transmitter, and the backscattered received signal corresponding to the backscattered signal of the backscattering device; an elimination module for eliminating interference of the main link channel based on a channel estimation operation; and a calculation module for recovering the baseband signal and the multiple backscattered received signals based on a collaborative parallel detection operation.

[0036] According to another aspect of the present disclosure, a network device is provided, including: a processor; and a memory for storing executable instructions of the processor; the processor is configured to perform the above-mentioned backscatter Internet of Things communication method by executing the executable instructions.

[0037] According to another aspect of the present disclosure, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the above-mentioned backscatter Internet of Things communication method is implemented.

[0038] The backscattering Internet of Things system and communication method provided by the embodiments of the present disclosure are such that, in the backscattering Internet of Things system, a received downlink signal is orthogonally modulated by multiple backscattering devices to obtain a corresponding backscattering signal. Multiple backscattering devices send backscattering signals in parallel, so that a receiver can perform collaborative and parallel detection on the received baseband signal and the backscattering reception signal to simultaneously recover the received baseband signal and the backscattering reception signal. The system can eliminate interference in the main link channel and avoid mutual interference between multiple backscattering devices, which is conducive to the deployment of multiple backscattering devices and reduces the occupation of spectrum resources, thereby realizing parallel and reliable transmission of backscattering signals of multiple backscattering devices.

[0039] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification, are used to explain the principles of the present disclosure. Obviously, the drawings described below are only some embodiments of the present disclosure, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0041] Figure 1 A schematic diagram of a backscattering Internet of Things system according to an embodiment of the present disclosure is shown;

[0042] Figure 2 A schematic diagram of a signal frame structure in a backscatter IoT communication solution according to an embodiment of the present disclosure is shown;

[0043] Figure 3 A schematic diagram showing a signal waveform in a backscattering IoT communication solution according to an embodiment of the present disclosure is shown;

[0044] Figure 4 A schematic block diagram of a backscattering device according to an embodiment of the present disclosure is shown;

[0045] Figure 5 A flow chart of a backscattering IoT communication method according to an embodiment of the present disclosure is shown;

[0046] Figure 6 A flow chart of another backscattering IoT communication method according to an embodiment of the present disclosure is shown;

[0047] Figure 7 A flow chart of another backscattering Internet of Things communication method according to an embodiment of the present disclosure is shown;

[0048] Figure 8 A schematic diagram showing a curve of a signal bit error rate in an embodiment of the present disclosure;

[0049] Figure 9 A schematic diagram showing another curve of a signal bit error rate in an embodiment of the present disclosure;

[0050] Figure 10 A schematic diagram of a backscattering IoT communication device according to an embodiment of the present disclosure is shown;

[0051] Figure 11 A schematic diagram of another backscattering IoT communication device according to an embodiment of the present disclosure is shown;

[0052] Figure 12 A structural block diagram of a computer device according to an embodiment of the present disclosure is shown;

[0053] Figure 13 A structural block diagram of a program product in an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0054] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be embodied in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0055] In addition, the accompanying drawings are merely schematic illustrations of the present disclosure and are not necessarily drawn to scale. Identical reference numerals in the figures denote identical or similar parts, and thus repetitive descriptions thereof will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities that do not necessarily correspond to physically or logically separate entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0056] Backscatter communication technology is a key technology in the design of a "green" IoT and 6G networks, enabling low-power, low-cost, and easily deployable "green" communications. Backscatter passive devices can utilize third-party signals (such as cellular wireless signals, broadcast television signals, Wi-Fi signals, or Bluetooth signals) to transmit their own information. This involves modulating the RF signals from other devices or the environment to transmit their own information. However, current challenges include difficulty in achieving large-scale simultaneous device access and interference between primary and secondary channels, as well as between secondary channels.

[0057] The solution provided in the present application is to orthogonally modulate the received downlink signal through multiple backscattering devices to obtain corresponding backscattering signals. Multiple backscattering devices send backscattering signals in parallel, so that the receiver can perform collaborative parallel detection on the received baseband signal and the backscattering reception signal to simultaneously restore the received baseband signal and the backscattering reception signal. The system can eliminate interference in the main link channel and avoid mutual interference between multiple backscattering devices, which is conducive to the deployment of multiple backscattering devices and reduces the occupation of spectrum resources, thereby realizing parallel and reliable transmission of backscattering signals of multiple backscattering devices.

[0058] Below, each step of the backscattering IoT system and the backscattering IoT communication method in this example implementation will be described in more detail with reference to the accompanying drawings and embodiments.

[0059] like Figure 1 As shown, a backscatter IoT communication system according to an embodiment of the present disclosure includes a primary transmitter 10 (PT), multiple backscatter devices 20 (BD) and a primary receiver 30 (PR).

[0060] The main transmitter 10 is used to send downlink signals.

[0061] Multiple backscatter devices, including 20A, 20B, and 20K, are used to perform orthogonal modulation on the received downlink signal to generate multiple backscatter signals.

[0062] Multiple backscatter devices 30 are also used to send multiple backscatter signals in parallel.

[0063] The receiver PR is configured to receive a baseband signal based on a primary link channel and a plurality of backscattered received signals based on a plurality of secondary link channels, wherein the baseband signal corresponds to a downlink signal and the backscattered received signal corresponds to a backscattered signal;

[0064] The receiver PR is further configured to: cancel interference of the primary link channel based on a channel estimation operation;

[0065] The receiver PR is further configured to recover the baseband signal and the multiple backscattered received signals based on a coordinated parallel detection operation on the multiple backscattered received signals.

[0066] In this embodiment, in the backscattering Internet of Things system, the received downlink signal is orthogonally modulated by multiple backscattering devices to obtain corresponding backscattering signals. The multiple backscattering devices send the backscattering signals in parallel, so that the receiver can perform collaborative parallel detection on the received baseband signal and the backscattering reception signal to simultaneously restore the received baseband signal and the backscattering reception signal. The system can eliminate interference in the main link channel and avoid mutual interference between multiple backscattering devices, which is conducive to the deployment of multiple backscattering devices and reduces the occupation of spectrum resources, thereby realizing parallel and reliable transmission of backscattering signals of multiple backscattering devices.

[0067] In one embodiment, the backscattering device is also used to: perform orthogonal coding processing based on the downlink signal to generate an on-off keyed code chip sequence to generate a backscattering signal based on the code chip sequence, the code chip sequences of multiple backscattering devices constitute a Hadamard orthogonal matrix, and the code chip sequence includes L-bit code chips, wherein the downlink signal has a first frame structure, the first frame structure includes multiple first signal periods, the backscattering signal has a second frame structure, the second frame structure includes multiple second signal periods, the second signal period is L×M times the first signal period, L is the number of code chip bits for orthogonal coding, and M is the ratio of the code chip period to the first signal period.

[0068] like Figure 2 As shown, the first frame structure is the frame structure of the downlink signal, and the second frame structure is the frame structure of the backscatter signal. l,m is the downlink signal sent by PT, x k is the backscattered signal.

[0069] L is the number of chips of the orthogonal code, M is the ratio of the chip period to the source symbol period, and K is the number of backscatter devices.

[0070] T bThe encoding symbol period for the backscatter device BD, i.e. the second signal period, T s The source symbol period sent by PT, that is, the first signal period, T b =LMT s .

[0071] During the coherence time of a channel, which includes N second signal periods, at the beginning of each channel coherence time interval, the PT sends a pilot to estimate the primary link channel h0, followed by the downlink data symbol. Note that when the PT sends the pilot, the BD is in a silent state, and the BD uses the PT's data signal to modulate its own information.

[0072] Specifically, the second frame structure includes n second signal cycles, the timing in each channel coherence time interval, and the [(l-1)M+m]th data symbol of the downlink signal in the nth second signal cycle is identified as s l,m (n), s l,m (n)∈A s ,|A s |=1, where l is the chip number of the orthogonal code and m is the number corresponding to M.

[0073] The signal sent by the backscatter device BD in the nth second signal cycle is the OOK (On-Off Keying) modulation symbol x k (n), x k (n)∈A x ,A s =0,1.

[0074] Figure 3 The waveforms of the downlink signal and the backscattered signal when L=2 and M=3 are shown. The waveform design needs to meet the condition L≥K.

[0075] like Figure 3 As shown, within n second signal cycles, there are 2×3=6 first signal cycles, namely s 1,1 (n), s 1,2 (n), s 1,3 (n), s 2,1 (n), s 2,2 (n) and s 2,3 (n).

[0076] c k is the orthogonal coding vector, which is represented by the code chip [C k,1 ,…,C k,L ], the backscattered signal x k (n) Orthogonal modulation is performed using orthogonal coding vectors, where each chip lasts M×T s time, the channel estimation error can be eliminated in the subsequent process.

[0077] In one embodiment, the receiver is further configured to determine a received joint data signal based on a baseband signal, a backscattered received signal, and Gaussian white noise received in each second signal period of the channel coherence time interval.

[0078] In one embodiment, the primary transmitter is further configured to: send a pilot signal at the start position of the coherence time interval of each link channel, the pilot signal being used to estimate the primary link channel, wherein when the primary transmitter sends the pilot signal, the backscatter device is in a silent state. The receiver is further configured to: based on the pilot signal x p Generate the received signal y p ; Input the pilot signal and the pilot received signal into the channel estimation model to estimate the main link channel.

[0079] In one embodiment, the receiver is further used to: perform minimum distance decoding based on the main link channel, the baseband signal and the joint data signal to obtain a source signal; determine the interference signal of the main link channel based on the source signal; eliminate the interference signal from the joint data signal to obtain a corresponding device received signal; and optimize the device received signal based on the reflection coefficient of the backscattering device to obtain an intermediate variable.

[0080] In one embodiment, the backscattered received signal is represented based on a high-level bit and a low-level bit, and the receiver is further used to: calculate a test statistic of the backscattered received signal based on an intermediate variable; perform a maximum likelihood decision on the test statistics corresponding to the high-level bit and the low-level bit based on a coordinated parallel detection operation of multiple backscattered received signals; and restore the baseband signal and multiple backscattered received signals based on the decision result of the maximum likelihood decision.

[0081] In one embodiment, the receiver is further used to: obtain all intermediate variables within a second signal period; perform decoding operations on all intermediate variables based on a decoding matrix to obtain a test statistic matrix; restore key test statistics of the backscattered received signal based on the test statistic matrix; determine the cumulative estimation error of the main link channel based on the orthogonality of the backscattered received signal; determine the correspondence between each secondary link channel and the corresponding key test statistic based on the cumulative estimation error; adjust the key test statistic based on the correspondence to obtain the test statistic of the backscattered received signal based on the second signal period.

[0082] In one embodiment, the receiver is also used to: determine a first Gaussian distribution of the test statistic under a low-level bit and a second Gaussian distribution of the test statistic under a high-level bit based on the complex Gaussian distribution of the test statistic; construct a first probability density function of the test statistic based on the low-level bit; construct a second probability density function of the test statistic based on the high-level bit; and perform maximum likelihood estimation based on the first probability density function and the second probability density function to estimate a first mean and a second mean of the complex Gaussian distribution.

[0083] In one embodiment, the receiver is further configured to determine an interference cancellation result of the primary link channel on the secondary link channel based on estimation results of the first mean value and the second mean value.

[0084] In one embodiment, the receiver is further used to: construct a statistical decision quantifier for each backscatter device based on the difference between the first mean and the second mean, and a test statistic; construct a decision threshold based on the relationship between the first mean and the second mean; and recover the baseband signal and multiple backscatter received signals based on the relationship between the statistical decision quantifier and the decision threshold.

[0085] In one embodiment, the receiver is further used to: construct a conditional bit error rate model for each secondary link channel based on the relationship between the statistical decision amount and the decision threshold under low-level bits, and the relationship between the statistical decision amount and the decision threshold under high-level bits; and calculate the theoretical bit error rate of each secondary link channel based on the conditional bit error rate model.

[0086] like Figure 4 As shown, in one embodiment, the backscatter device 400 includes:

[0087] Antenna 402 is used to receive downlink signals and transmit backscattered signals.

[0088] The signal modulation module 404 is configured to perform orthogonal coding modulation on the downlink signal to obtain a backscattered signal.

[0089] The control module 406 is used to control the signal modulation module to perform modulation operations.

[0090] The power supply module 408 is used to supply power to the signal modulation module and the control module.

[0091] In addition, the backscatter device 400 further includes a sensor module 410 .

[0092] Figure 5 A flow chart of a backscattering Internet of Things communication method in an embodiment of the present disclosure is shown.

[0093] like Figure 5 As shown, a backscattering IoT communication method according to an embodiment of the present disclosure is applied to a backscattering device and includes the following steps:

[0094] Step S502: Receive a downlink signal sent by a primary transmitter.

[0095] Step S504: perform orthogonal modulation on the downlink signal to generate a backscattered signal.

[0096] Step S506: Send a backscattered signal.

[0097] In this embodiment, multiple backscattering devices in the backscattering Internet of Things system perform orthogonal modulation on the received downlink signal to obtain corresponding backscattering signals. Multiple backscattering devices send backscattering signals in parallel, which is conducive to the deployment of multiple backscattering devices and reduces the occupation of spectrum resources, thereby realizing parallel and reliable transmission of backscattering signals of multiple backscattering devices.

[0098] In one embodiment, orthogonal modulation is performed on a downlink signal to generate a backscatter signal, including: performing orthogonal coding processing based on the downlink signal to generate an on-off keyed code chip sequence to generate a backscatter signal based on the code chip sequence, the code chip sequences of multiple backscatter devices constitute a Hadamard orthogonal matrix, and the code chip sequence includes L-bit code chips.

[0099] Among them, the downlink signal has a first frame structure, the first frame structure includes multiple first signal periods, the backscattered signal has a second frame structure, the second frame structure includes multiple second signal periods, the second signal period is L×M times the first signal period, L is the number of code chip bits of orthogonal coding, and M is the ratio of the code chip period to the first signal period.

[0100] Specifically, the second frame structure includes n second signal cycles, the timing in each channel coherence time interval, and the [(l-1)M+m]th data symbol of the downlink signal in the nth second signal cycle is identified as s l,m (n), s l,m (n)∈A s ,|A s |=1, where l is the chip number of the orthogonal code and m is the number corresponding to M.

[0101] The data symbol of the backscattered signal in the n second signal period is x k (n).

[0102] Figure 6 A flow chart of a backscattering Internet of Things communication method in an embodiment of the present disclosure is shown.

[0103] like Figure 6 As shown, the backscattering Internet of Things communication method according to an embodiment of the present disclosure is applied to a receiver and includes the following steps:

[0104] Step S602: receiving a baseband signal based on a primary link channel and receiving multiple backscattered reception signals based on multiple secondary link channels, wherein the baseband signal corresponds to a downlink signal of a primary transmitter and the backscattered reception signal corresponds to a backscattered signal of a backscattering device.

[0105] The receiver receives the [(l-1)M+m]th baseband signal from the main transmitter in the nth time period of the backscatter device as shown in formula (1):

[0106]

[0107] Among them, h0 is the impulse response of the main channel link.

[0108] The receiver receives the [(l-1)M+m]th backscatter reception signal from the backscatter device in the nth time period of the backscatter device as shown in formula (2):

[0109]

[0110] Among them, α k is the reflection coefficient of the kth BD.

[0111] Step S604: Eliminate interference of the primary link channel based on the channel estimation operation.

[0112] Step S606: Recover the baseband signal and multiple backscattered received signals based on the coordinated parallel detection operation.

[0113] In this embodiment, the receiver in the backscattering Internet of Things system orthogonally modulates the received downlink signal through multiple backscattering devices to obtain corresponding backscattering signals. The multiple backscattering devices send the backscattering signals in parallel, so that the receiver can perform collaborative parallel detection on the received baseband signal and the backscattering reception signal to simultaneously recover the received baseband signal and the backscattering reception signal. The system can eliminate interference in the main link channel and avoid mutual interference between multiple backscattering devices, which is conducive to the deployment of multiple backscattering devices and reduces the occupation of spectrum resources, thereby realizing parallel and reliable transmission of backscattering signals of multiple backscattering devices.

[0114] In one embodiment, receiving a baseband signal based on a primary link channel and receiving a plurality of backscattered receive signals based on a plurality of secondary link channels further comprises:

[0115] A received joint data signal is determined based on the baseband signal, the backscattered received signal and the Gaussian white noise received in each second signal period of the channel coherence time interval.

[0116] The [(l-1)M+m]th joint data signal is shown in formula (3):

[0117]

[0118] in, represents Gaussian white noise.

[0119] In this embodiment, by acquiring the joint data signal, on the one hand, the interference signal of the main link channel is further detected based on the joint data signal, and the interference of the main link channel is eliminated; on the other hand, the baseband signal and multiple backscattered received signals are further recovered based on the joint data signal.

[0120] In one embodiment, a specific implementation of step S604, eliminating interference of the primary link channel based on the channel estimation operation, includes:

[0121] At the beginning of each block fading channel, PT sends a pilot signal x p To estimate the direct link channel

[0122]

[0123] Get pilot signal x p The pilot received signal y p , pilot signal x p Sent by the primary transmitter PT at the beginning of the channel coherence time interval.

[0124] The pilot signal x p and pilot received signal y p Input channel estimation model to estimate the main link channel

[0125] Eliminate the main link channel interference.

[0126] In this embodiment, by receiving the pilot signal y p The main link channel is estimated to eliminate interference on the main link channel and ensure reliability of recovery operations of the baseband signal and the backscattered received signal.

[0127] In one embodiment, the method further includes: constructing a channel estimation model based on a least squares estimation (LS) model and / or a minimum mean-square error (MMSE) model.

[0128] Specifically, the ML (Maximum Likelihood) estimation method is used to obtain the pilot received signal y pEstimate the main link channel as shown in equation (4).

[0129]

[0130] In one embodiment, eliminating interference on a primary link channel includes:

[0131] Perform minimum distance decoding based on the main link channel, baseband signal and joint data signal to obtain the source signal As shown in formula (5).

[0132]

[0133] An interfering signal for the primary link channel is determined based on the source signal.

[0134] Among them, the interference signal can be expressed as

[0135] Eliminate the interference signal from the joint data signal to obtain the corresponding device receiving signal As shown in formula (6).

[0136]

[0137] In this embodiment, the source signal is obtained by performing minimum distance decoding on the joint data signal, so as to determine the interference of the main link channel based on the source signal and the main link channel, thereby further eliminating direct interference and ensuring the accuracy of the detection of the device receiving signal received by the receiver.

[0138] In one embodiment, the method further includes: receiving a signal from the device based on a reflection coefficient of the backscattering device. Optimize and get intermediate variables

[0139] Specifically, the reflection coefficients of all BDs are the same, that is, α1 = α2 = ... = α n =α, further get the intermediate variable As shown in formula (7):

[0140]

[0141] in,

[0142] like Figure 7 As shown, in one embodiment, the backscattered received signal is represented based on a high-level bit and a low-level bit, and a baseband signal and multiple backscattered received signals are recovered based on a coordinated parallel detection operation, including:

[0143] Step S702: Calculate the test statistic of the backscattered received signal based on the intermediate variable.

[0144] Step S704 : Based on the coordinated parallel detection operation of the plurality of backscattered received signals, a maximum likelihood decision is performed on the test statistics corresponding to the high level bits and the low level bits.

[0145] The backscattered received signal is represented by high-level bits and low-level bits, that is, "1010" is used to represent the backscattered received signal. Based on the orthogonal modulation of the backscattering device, the backscattering device sends bits 0 or 1 with equal probability.

[0146] In addition, maximum likelihood judgment is used to determine the number and strength of backscattered received signals based on test statistics to achieve signal recovery.

[0147] Step S706: Restore the baseband signal and the multiple backscattered received signals based on the decision result of the maximum likelihood decision.

[0148] In this embodiment, a plurality of intermediate variables within a second signal period are obtained to construct a corresponding test statistic, the test statistic corresponding to the backscattered received signal, and further a maximum likelihood decision is performed on the test statistic to enable the receiver to perform maximum likelihood detection without knowing the secondary link channel of the backscattered device, so as to recover the baseband signal and multiple backscattered received signals.

[0149] In one embodiment, a specific implementation of step S702, calculating a test statistic of a backscattered received signal based on an intermediate variable, includes:

[0150] Get all the intermediate variables within a second signal period and get r H (n), as shown in formula (8).

[0151]

[0152] Based on the decoding matrix, decoding operations are performed on all intermediate variables to obtain a test statistic matrix.

[0153] Among them, the decoding matrix is ​​C = [c1, c2, ...c k ] K×LM .

[0154] c k =[C k,1 ,C k,1 ,…,C k,2 ,C k,2 ,…,C k,L ] H .

[0155] The constructed test statistic matrix is ​​shown in formula (9).

[0156] rH (n)×C=[t1(n),…,t k (n),…,t K (n)] (9)

[0157] The key test statistics of the backscattered received signal are recovered based on the test statistic matrix, as shown in Equation (10).

[0158]

[0159]

[0160] Determine the cumulative estimation error e of the main link channel based on the orthogonality of the backscattered received signal k .

[0161] The orthogonality of the orthogonal code is expressed as shown in formula (11), and this property can be used to eliminate the mutual interference between the secondary link channels of multiple BDs.

[0162]

[0163] Cumulative estimation error e k As shown in formula (12).

[0164]

[0165] A correspondence between each secondary link channel and a corresponding key test statistic is determined based on the accumulated estimation error.

[0166] Based on the corresponding relationship, the key test statistic is adjusted to obtain the test statistic t of the backscattered received signal based on the second signal period. k (n), as shown in formula (13).

[0167] t k (n) = Lh k x k (n)+e k +z(n) (13)

[0168] in,

[0169] In one embodiment, based on the coordinated parallel detection operation of multiple backscattered received signals, performing maximum likelihood decision on the test statistics corresponding to the high level bit and the low level bit includes:

[0170] Based on the complex Gaussian distribution of the test statistic, a first Gaussian distribution of the test statistic under the low-level bit and a second Gaussian distribution of the test statistic under the high-level bit are determined.

[0171] Assume that H0 and H1 represent the tag transmission symbol x k (n) = 0 and x k (n) = 1, the test statistic sweep t k (n) = 0 is a complex Gaussian distribution, as shown in formula (14).

[0172]

[0173] in, μ 0,k and μ 1,k is the average value of the backscattered received signal of the kth backscattering device BD under the assumptions H0 and H1.

[0174] A first initial representation of a first mean corresponding to a first Gaussian distribution and a second initial representation of a second mean corresponding to a second Gaussian distribution are constructed based on the accumulated channel estimation error and the secondary channel link of the backscatter device.

[0175] Among them, the first initial representation μ 0,k =e k , the second initial representation μ 1,k =e k +LMh k .

[0176] For the low-level bit, the first probability density function f(t k |H0), as shown in formula (15).

[0177]

[0178] For the high level bit, the second probability density function f(t k |H1), as shown in formula (16).

[0179]

[0180] The Hadamard orthogonal matrix is ​​used as a spread spectrum orthogonal code, and maximum likelihood estimation of the first probability density function and the second probability density function is performed to obtain a first intermediate representation of the first mean and a second intermediate representation of the second mean.

[0181] Maximum likelihood estimation is performed based on the first probability density function and the second probability density function to estimate a first mean and a second mean of the complex Gaussian distribution.

[0182] The maximum likelihood estimation based on the first probability density function and the second probability density function is shown in formula (17).

[0183]

[0184] For the kth backscatter device, that is, k = 1, since the orthogonal code used is all 1, the first intermediate representation is The second intermediate representation is h k is the impulse response of the secondary link channel.

[0185] For the remaining backscatter devices, i.e., k≠1, the number of +1 and -1 in the orthogonal code is the same, and the first intermediate representation is μ 0,k =e k =0, the second intermediate representation is μ 1,k =LMh k .

[0186] Based on the collaborative parallel detection operation, all test statistics within the channel coherence time are sorted, and a first target representation of a first mean and a second target representation of a second mean are generated based on the sorting results and the corresponding relationship.

[0187] In practice, considering that the backscatter device sends bits 0 or 1 with equal probability, when BD sends bit 0, t k The value of is smaller, and when bit 1 is sent, t k The value of is larger, and all values ​​within the channel coherence time are sorted from small to large. The first half is the case of sending bit 0, and the second half is the case of sending bit 1.

[0188] The first objective of the first mean is expressed as: In the second half, k≠1:μ 0,k =0.

[0189] The second objective of the second mean is expressed as: In the first half,

[0190] In this embodiment, based on the maximum likelihood detection of the test statistic, the detection processing of the receiver explicitly considers the influence of the time dispersion of the wireless channel, and the distribution parameters of the complex Gaussian distribution are estimated to determine the signal most likely to be received, thereby achieving signal recovery.

[0191] In one embodiment, the method further includes: determining an interference cancellation result of the primary link channel to the secondary link channel based on the estimation results of the first mean value and the second mean value.

[0192] In this embodiment, when k≠1, e k =0, it indicates that the interference of the primary link to the secondary link has been eliminated.

[0193] In one embodiment, based on the decision result of the maximum likelihood decision, restoring the baseband signal and the plurality of backscattered received signals includes:

[0194] The statistical decision value R of each backscatter device is constructed based on the difference between the first mean and the second mean and the test statistic k , as shown in formula (18).

[0195] R k =Re{t k (μ 1,k -μ 0,k )} (18)

[0196] Construct a decision threshold γ based on the relationship between the first mean and the second mean k , as shown in formula (19).

[0197]

[0198] The baseband signal and multiple backscattered received signals are restored based on the relationship between the statistical decision amount and the decision threshold.

[0199] In this embodiment, by constructing corresponding statistical decision quantities and decision thresholds based on the first mean and the second mean, the baseband signal and multiple backscattered received signals recovered based on the relationship between the statistical decision quantity and the decision threshold can have the minimum bit error rate.

[0200] In one embodiment, it further includes:

[0201] Based on the relationship between the statistical decision amount and the decision threshold under low-level bits, and the relationship between the statistical decision amount and the decision threshold under high-level bits, a conditional bit error rate model of each secondary link channel is constructed.

[0202] Specifically, since the statistical decision metric obeys the Gaussian distribution, the statistical decision metric can also be expressed as formula (20):

[0203]

[0204] The corresponding decision threshold is shown in formula (19).

[0205] The conditional bit error rate model of the constructed secondary link channel is shown in formula (21).

[0206]

[0207] The theoretical bit error rate of each secondary link channel is calculated based on the conditional bit error rate model, as shown in formula (22).

[0208]

[0209] In one embodiment, the method further includes: obtaining a detection bit error rate detected based on an energy detection model; and obtaining detection results of the detection bit error rate and the theoretical bit error rate.

[0210] like Figure 8 As shown, the first detector is a traditional energy detector, and the second detector is a cooperative parallel detection in the present disclosure, where L=8, M=4 (i.e., 8 BD devices are connected at the same time, and the chip period is 4 times the source symbol period). The simulation results based on the first detector and the second detector are shown in FIG. Figure 8 As shown, based on the average bit error rate curve of the backscattered signals detected by the first detector and the second detector, it can be seen that multiple BDs are accessed simultaneously and a lower BD average bit error rate is achieved than that of the traditional energy detection method.

[0211] In addition, the solution disclosed in this disclosure eliminates channel interference, including interference between multiple BD devices and interference from the main channel link. Under low signal-to-noise ratio conditions, the possibility of error in source signal recovery is high, so the performance of MBPND is not as good as theoretical analysis.

[0212] like Figure 9 As shown, the bit error rate of the source baseband signal demodulation in the first backscattering Internet of Things system (the number of backscattering devices = 16), the second backscattering Internet of Things system (the number of backscattering devices = 8) and the separate system network (no backscattering devices) are respectively shown as a function of the direct link signal-to-noise ratio.

[0213] like Figure 9 As shown in the figure, compared with a single system network, the more BDs are integrated in the backscatter IoT system, the worse the bit error rate performance is. However, the bit error rate is still acceptable in actual application scenarios. Therefore, the solution disclosed in the present invention can realize large-scale environmental backscatter IoT communication.

[0214] The parallel and reliable transmission of multiple backscattering IoT devices increases the number of multi-device communications on the same time-frequency resources, while avoiding the disadvantages of occupying more spectrum resources and channel congestion. Multiple BDs can access each other without interference, which is conducive to reducing the bit error rate and improving the accuracy of signal detection.

[0215] It should be noted that the above figures are merely illustrative of the processes included in the method according to exemplary embodiments of the present invention and are not intended to be limiting. It is readily understood that the processes illustrated in the above figures do not indicate or limit the temporal order of these processes. Furthermore, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0216] Refer to the following Figure 10 hereinafter, a backscatter IoT communication device 1000 according to an embodiment of the present invention is described. Figure 10 The backscatter IoT communication device 1000 shown is merely an example and should not limit the functions and scope of use of the embodiments of the present invention.

[0217] Backscatter IoT communication device 1000 is implemented as a hardware module. Its components may include, but are not limited to: a first receiving module 1002 for receiving downlink signals from a primary transmitter; a modulation module 1004 for performing orthogonal modulation on the downlink signals to generate backscatter signals; and a transmitting module 1006 for transmitting the backscatter signals.

[0218] Refer to the following Figure 11 1 and 2 to describe the backscatter IoT communication device 1100 according to an embodiment of the present invention. Figure 11 The backscatter IoT communication device 1100 shown is merely an example and should not limit the functionality and scope of use of the embodiments of the present invention.

[0219] The backscatter IoT communication device 1100 is implemented as a hardware module. The components of the backscatter IoT communication device 1100 may include, but are not limited to: a second receiving module 1102 for receiving a baseband signal based on a primary link channel and multiple backscattered received signals based on multiple secondary link channels, wherein the baseband signal corresponds to a downlink signal from a primary transmitter and the backscattered received signals correspond to backscattered signals from a backscattering device; a cancellation module 1104 for canceling interference from the primary link channel based on a channel estimation operation; and a recovery module 1106 for recovering the baseband signal and the multiple backscattered received signals based on a coordinated parallel detection operation.

[0220] Those skilled in the art will appreciate that various aspects of the present invention may be implemented as systems, methods, or program products. Therefore, various aspects of the present invention may be implemented in the following forms: a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or a combination of hardware and software implementations, which may be collectively referred to herein as "circuits," "modules," or "systems."

[0221] Refer to the following Figure 12 The network device 1200 according to this embodiment of the present invention is described. Figure 12 The network device 1200 shown is merely an example and should not limit the functionality and scope of use of the embodiments of the present invention.

[0222] like Figure 12 As shown, network device 1200 is implemented as a general-purpose computing device. Components of network device 1200 may include, but are not limited to, the aforementioned at least one processing unit 1210, the aforementioned at least one storage unit 1220, and a bus 1230 connecting various system components (including storage unit 1220 and processing unit 1210).

[0223] The storage unit stores program codes, which can be executed by the processing unit 1210, so that the processing unit 1210 performs the steps according to various exemplary embodiments of the present invention described in the above “Exemplary Method” section of this specification. For example, the processing unit 1210 can perform the following steps: Figure 6 The solution described in steps S602 to S606 shown in FIG.

[0224] The storage unit 1220 may include a readable medium in the form of a volatile storage unit, such as a random access memory unit (RAM) 12201 and / or a cache memory unit 12202 , and may further include a read-only memory unit (ROM) 12203 .

[0225] The storage unit 1220 may also include a program / utility 12204 having a set (at least one) of program modules 12205, such program modules 12205 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0226] The bus 1230 may represent one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0227] The network device 1200 may also communicate with one or more external devices 1270 (e.g., a keyboard, a pointing device, a Bluetooth device, etc.), one or more devices that enable a user to interact with the network device 1200, and / or any device that enables the network device 1200 to communicate with one or more other computing devices (e.g., a router, a modem, etc.). Such communication may occur via an input / output (I / O) interface 1250. Furthermore, the network device 1200 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) via a network adapter 1260. As shown, the network adapter 1260 communicates with other modules of the network device 1200 via a bus 1230. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the network device 1200, including but not limited to microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0228] Through the description of the above embodiments, it is easy for those skilled in the art to understand that the example embodiments described herein can be implemented by software or by combining software with necessary hardware. Therefore, the technical solution according to the embodiments of the present disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, and includes several instructions to enable a computing device (which can be a personal computer, a server, a terminal device, or a network device, etc.) to execute the method according to the embodiments of the present disclosure.

[0229] In exemplary embodiments of the present disclosure, a computer-readable storage medium is also provided, on which is stored a program product capable of implementing the aforementioned methods of this specification. In some possible implementations, various aspects of the present invention may also be implemented in the form of a program product comprising program code that, when executed on a network device, causes the network device to perform the steps according to various exemplary embodiments of the present invention described in the "Exemplary Methods" section of this specification.

[0230] refer to Figure 13 , a program product 1300 for implementing the above-described method according to an embodiment of the present invention is described. The program product 1300 may be a portable compact disk read-only memory (CD-ROM) and include program code, and may be run on a network device, such as a personal computer. However, the program product of the present invention is not limited thereto. In this document, a readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0231] The program product may be implemented in any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or component, or any combination thereof. More specific examples (a non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof.

[0232] A computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, which carries readable program code. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable signal medium may also be any readable medium other than a readable storage medium that can transmit, propagate, or transfer a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0233] The program code embodied on the readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0234] The program code for performing the operations of the present invention may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, and the like, as well as conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a stand-alone software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving a remote computing device, the remote computing device may be connected to the user computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0235] It should be noted that although several modules or units of the device for action execution are mentioned in the detailed description above, this division is not mandatory. In fact, according to the embodiments of the present disclosure, the features and functions of two or more modules or units described above can be concretized in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided into multiple modules or units to be concretized.

[0236] Furthermore, although the steps of the method of the present disclosure are described in a particular order in the accompanying drawings, this does not require or imply that the steps must be performed in this particular order, or that all steps shown must be performed to achieve the desired results. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be decomposed into multiple steps.

[0237] Through the description of the above embodiments, it is easy for those skilled in the art to understand that the example embodiments described herein can be implemented by software or by combining software with necessary hardware. Therefore, the technical solution according to the embodiments of the present disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, and includes several instructions to enable a computing device (which can be a personal computer, a server, a mobile terminal, or a network device, etc.) to execute the method according to the embodiments of the present disclosure.

[0238] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the present disclosure being indicated by the appended claims.

Claims

1. A backscattering Internet of Things system, characterized in that: include: A main transmitter for transmitting a downlink signal and a plurality of backscattering devices for generating and transmitting a plurality of backscattering signals in parallel based on the downlink signal; a receiver for receiving a baseband signal corresponding to the downlink signal based on a primary link channel and a plurality of backscattered reception signals based on a plurality of secondary link channels; The receiver is also used to: perform minimum distance decoding based on the main link channel, the baseband signal and the received joint data signal to obtain a source signal, determine an interference signal based on the source signal, the joint data signal is determined based on the baseband signal, the backscattered received signal and Gaussian white noise received in each second signal period of the channel coherence time interval, eliminate the interference signal from the joint data signal to obtain a corresponding device received signal; the backscattered received signal is represented based on high-level bits and low-level bits, and the device received signal is used as a numerator, and the square root of the signal power of the downlink signal, the product of the source signal and the reflection coefficient of the backscattered device are used as a denominator to obtain an intermediate variable, Decoding all intermediate variables within the second signal period to recover a key test statistic of the backscattered received signal, adjusting the key test statistic based on the accumulated estimation error of the main link channel to obtain a test statistic, constructing a first probability density function and a second probability density function based on the test statistics corresponding to the high-level bit and the low-level bit, respectively, performing maximum likelihood estimation based on the first probability density function and the second probability density function to obtain corresponding first and second means, constructing a statistical decision metric for each of the backscattering devices based on a difference between the first and second means and the test statistic; and constructing a decision threshold based on the relationship between the first and second means; The baseband signal and the plurality of backscattered received signals are restored based on the relationship between the statistical decision quantity and the decision threshold.

2. The backscattering Internet of Things system according to claim 1, characterized in that: The backscattering device is further configured to perform orthogonal coding processing based on the downlink signal to generate an on-off keyed chip sequence, so as to generate the backscattering signal based on the chip sequence, wherein the chip sequences of the plurality of backscattering devices constitute a Hadamard orthogonal matrix, and the chip sequence includes L-bit chips. In which, the downlink signal has a first frame structure, the first frame structure includes multiple first signal periods, the backscattered signal has a second frame structure, the second frame structure includes multiple second signal periods, the second signal period is L×M times the first signal period, L is the number of code chip bits of the orthogonal coding, and M is the ratio of the code chip period to the first signal period.

3. The backscattering Internet of Things system according to claim 2, characterized in that: The receiver is further configured to determine a received joint data signal based on the baseband signal, the backscattered received signal, and Gaussian white noise received within each second signal period of the channel coherence time interval.

4. The backscattering Internet of Things system according to claim 3, characterized in that: The main transmitter is further configured to: Sending a pilot signal at the start position of the coherence time interval of each link channel, wherein the pilot signal is used to estimate the primary link channel, wherein when the primary transmitter sends the pilot signal, the backscatter device is in a silent state; The receiver is further configured to: generate a pilot reception signal based on the pilot signal; The pilot signal and the pilot reception signal are input into a channel estimation model to estimate the primary link channel.

5. The backscattering Internet of Things system according to claim 4, characterized in that: The receiver is further configured to: Perform minimum distance decoding based on the main link channel, the baseband signal and the joint data signal to obtain a source signal; determining an interference signal of the primary link channel based on the source signal; Eliminating the interference signal from the joint data signal to obtain a corresponding device reception signal; Based on the reflection coefficient of the backscattering device, the device receiving signal is optimized to obtain an intermediate variable.

6. The backscattering Internet of Things system according to claim 5, characterized in that: The receiver is further configured to: Acquire all the intermediate variables within a second signal period; Performing a decoding operation on all the intermediate variables based on a decoding matrix to obtain a test statistic matrix; Recovering a key test statistic of the backscattered received signal based on the test statistic matrix; determining a cumulative estimation error of the primary link channel based on orthogonality of the backscattered received signals; determining a correspondence between each of the secondary link channels and the corresponding key test statistic based on the accumulated estimation error; The key test statistic is adjusted based on the corresponding relationship to obtain the test statistic of the backscattered received signal based on the second signal period.

7. The backscattering Internet of Things system according to claim 6, characterized in that: The receiver is further configured to: Determining, based on the complex Gaussian distribution of the test statistic, a first Gaussian distribution of the test statistic under the low-level bit and a second Gaussian distribution of the test statistic under the high-level bit; constructing a first probability density function of the test statistic based on the low-level bits; constructing a second probability density function of the test statistic based on the high-level bits; Maximum likelihood estimation is performed based on the first probability density function and the second probability density function to estimate a first mean and a second mean of the complex Gaussian distribution.

8. The backscattering Internet of Things system according to claim 7, characterized in that: The receiver is further configured to: An interference cancellation result of the primary link channel to the secondary link channel is determined based on estimation results of the first mean value and the second mean value.

9. The backscattering Internet of Things system according to claim 1, wherein: The receiver is further configured to: constructing a conditional bit error rate model for each secondary link channel based on a relationship between the statistical decision amount and the decision threshold for the low-level bit, and a relationship between the statistical decision amount and the decision threshold for the high-level bit; The theoretical bit error rate of each of the secondary link channels is calculated based on the conditional bit error rate model.

10. The backscattering Internet of Things system according to any one of claims 1 to 9, characterized in that: The backscatter device comprises: an antenna, configured to receive the downlink signal and transmit the backscattered signal; A signal modulation module, configured to perform an orthogonal coding modulation operation on the downlink signal to obtain the backscattered signal; A control module, configured to control the signal modulation module to perform the modulation operation; A power supply module is used to supply power to the signal modulation module and the control module.

11. A backscatter Internet of Things communication method, characterized in that: Applications in backscatter equipment include: Receive downlink signals sent by the main transmitter; performing orthogonal modulation on the downlink signal to generate a backscattered signal; The backscatter signal is sent, and the backscatter signal corresponds to the backscatter received signal received by the receiver. The receiver performs minimum distance decoding based on the main link channel, the received baseband signal corresponding to the downlink signal and the joint data signal to obtain a source signal, and determines the interference signal based on the source signal. The joint data signal is determined based on the baseband signal, the backscatter received signal and Gaussian white noise received in each second signal period of the channel coherence time interval, and the interference signal is eliminated from the joint data signal to obtain the corresponding device received signal; the backscatter received signal is represented based on high-level bits and low-level bits, and the device received signal is used as a numerator, and the square root of the signal power of the downlink signal, the product of the source signal and the reflection coefficient of the backscatter device are used as a denominator to obtain an intermediate variable, and the All intermediate variables within the second signal period are decoded to recover the key test statistic of the backscattered received signal, the key test statistic is adjusted based on the cumulative estimation error of the main link channel to obtain a test statistic, a first probability density function and a second probability density function are constructed based on the test statistics corresponding to the high-level bit and the low-level bit, maximum likelihood estimation is performed based on the first probability density function and the second probability density function to obtain the corresponding first mean and second mean, a statistical decision quantifier for each of the backscattered devices is constructed based on the difference between the first mean and the second mean and the test statistic; a decision threshold is constructed based on the relationship between the first mean and the second mean; and the baseband signal and the multiple backscattered received signals are restored based on the relationship between the statistical decision quantifier and the decision threshold.

12. The backscattering Internet of Things communication method according to claim 11, characterized in that: The orthogonal modulation of the downlink signal to generate a backscatter signal includes: Performing orthogonal coding processing on the downlink signal to generate an on-off keyed chip sequence, and generating the backscatter signal based on the chip sequence, wherein the chip sequences of the plurality of backscatter devices form a Hadamard orthogonal matrix, and the chip sequence includes L-bit chips. In which, the downlink signal has a first frame structure, the first frame structure includes multiple first signal periods, the backscattered signal has a second frame structure, the second frame structure includes multiple second signal periods, the second signal period is L×M times the first signal period, L is the number of code chip bits of the orthogonal coding, and M is the ratio of the code chip period to the first signal period.

13. A backscatter Internet of Things communication method, characterized in that: Applications in receivers include: receiving a baseband signal based on a primary link channel and receiving a plurality of backscattered receive signals based on a plurality of secondary link channels, the baseband signal corresponding to a downlink signal of a primary transmitter, the backscattered receive signals corresponding to backscattered signals of a backscattering device; Eliminating interference from the primary link channel based on a channel estimation operation, wherein a source signal is obtained by performing minimum distance decoding on the primary link channel, the baseband signal, and a received joint data signal; an interference signal is determined based on the source signal; the joint data signal is determined based on the baseband signal, the backscattered received signal, and Gaussian white noise received within each second signal period of a channel coherence time interval; and the interference signal is eliminated from the joint data signal to obtain a corresponding device received signal; and The backscattered received signal is represented based on high-level bits and low-level bits, and the device received signal is used as a numerator, and the square root of the signal power of the downlink signal, the product of the source signal and the reflection coefficient of the backscattered device are used as a denominator to obtain an intermediate variable, all intermediate variables within the second signal period are decoded to recover the key test statistic of the backscattered received signal, the key test statistic is adjusted based on the cumulative estimation error of the main link channel to obtain a test statistic, a first probability density function and a second probability density function are constructed based on the test statistics corresponding to the high-level bits and the low-level bits, maximum likelihood estimation is performed based on the first probability density function and the second probability density function to obtain the corresponding first mean and second mean, a statistical decision quantifier for each backscattered device is constructed based on the difference between the first mean and the second mean and the test statistic; a decision threshold is constructed based on the relationship between the first mean and the second mean; and the baseband signal and the multiple backscattered received signals are recovered based on the relationship between the statistical decision quantifier and the decision threshold.

14. The backscatter Internet of Things communication method according to claim 13, wherein: The receiving of a baseband signal based on a primary link channel and receiving a plurality of backscattered received signals based on a plurality of secondary link channels further includes: A received joint data signal is determined based on the baseband signal, the backscattered received signal and Gaussian white noise received in each second signal period of the channel coherence time interval.

15. The backscattering Internet of Things communication method according to claim 14, characterized in that: Eliminating interference of the primary link channel based on a channel estimation operation includes: Acquire a pilot reception signal of a pilot signal, wherein the pilot signal is sent by a primary transmitter at a starting position of the channel coherence time interval; Inputting the pilot signal and the pilot received signal into a channel estimation model to estimate the primary link channel; Interference of the primary link channel is eliminated.

16. The backscattering Internet of Things communication method according to claim 15, characterized in that: Also includes: The channel estimation model is constructed based on a least square estimation model and / or a minimum mean square error estimation model.

17. The backscatter Internet of Things communication method according to claim 15, wherein: Eliminating interference of the main link channel includes: Perform minimum distance decoding based on the main link channel, the baseband signal and the joint data signal to obtain a source signal; determining an interference signal of the primary link channel based on the source signal; The interference signal is eliminated from the joint data signal to obtain a corresponding device reception signal.

18. The backscatter Internet of Things communication method according to claim 17, characterized in that: Also includes: Acquire all the intermediate variables within a second signal period; Performing a decoding operation on all the intermediate variables based on a decoding matrix to obtain a test statistic matrix; Recovering a key test statistic of the backscattered received signal based on the test statistic matrix; determining a cumulative estimation error of the primary link channel based on orthogonality of the backscattered received signals; determining a correspondence between each of the secondary link channels and the corresponding key test statistic based on the accumulated estimation error; The key test statistic is adjusted based on the corresponding relationship to obtain the test statistic of the backscattered received signal based on the second signal period.

19. The backscatter Internet of Things communication method according to claim 18, wherein: The method further comprises: constructing a first probability density function and a second probability density function based on the test statistics corresponding to the high-level bit and the low-level bit, and performing maximum likelihood estimation based on the first probability density function and the second probability density function to obtain corresponding first means and second means, including: Determining, based on the complex Gaussian distribution of the test statistic, a first Gaussian distribution of the test statistic under the low-level bit and a second Gaussian distribution of the test statistic under the high-level bit; constructing a first probability density function of the test statistic based on the low-level bits; constructing a second probability density function of the test statistic based on the high-level bits; Maximum likelihood estimation is performed based on the first probability density function and the second probability density function to estimate a first mean and a second mean of the complex Gaussian distribution.

20. The backscatter Internet of Things communication method according to claim 19, characterized in that: Also includes: An interference cancellation result of the primary link channel to the secondary link channel is determined based on estimation results of the first mean value and the second mean value.

21. The backscattering Internet of Things communication method according to claim 19, wherein: Also includes: constructing a conditional bit error rate model for each secondary link channel based on a relationship between the statistical decision amount and the decision threshold for the low-level bit, and a relationship between the statistical decision amount and the decision threshold for the high-level bit; The theoretical bit error rate of each of the secondary link channels is calculated based on the conditional bit error rate model.

22. The backscattering Internet of Things communication method according to any one of claims 13 to 21, characterized in that: Also includes: Obtaining the detection bit error rate detected based on the energy detection model; Obtain detection results of the detected bit error rate and the theoretical bit error rate.

23. A backscattering Internet of Things communication device, characterized in that: Applications in backscatter equipment include: A first receiving module, configured to receive a downlink signal sent by a main transmitter; A modulation module, configured to perform orthogonal modulation on the downlink signal to generate a backscattered signal; A sending module is used to send the backscattered signal, where the backscattered signal corresponds to the backscattered received signal received by the receiver, and the receiver performs minimum distance decoding based on the main link channel, the received baseband signal corresponding to the downlink signal, and the joint data signal to obtain a source signal, and determines the interference signal based on the source signal, the joint data signal is determined based on the baseband signal, the backscattered received signal, and Gaussian white noise received in each second signal period of the channel coherence time interval, and eliminates the interference signal from the joint data signal to obtain the corresponding device received signal; the backscattered received signal is represented based on high-level bits and low-level bits, and the device received signal is used as a numerator, and the square root of the signal power of the downlink signal, the product of the source signal and the reflection coefficient of the backscattering device are used as a denominator to obtain an intermediate variable The invention relates to a method for recovering a key test statistic of the backscattered received signal by decoding all intermediate variables within the second signal period, adjusting the key test statistic based on the cumulative estimation error of the main link channel to obtain a test statistic, constructing a first probability density function and a second probability density function based on the test statistics corresponding to the high-level bit and the low-level bit, performing maximum likelihood estimation based on the first probability density function and the second probability density function to obtain corresponding first and second means, constructing a statistical decision quantifier for each of the backscattered devices based on the difference between the first and second means and the test statistic; constructing a decision threshold based on the relationship between the first and second means; and recovering the baseband signal and the multiple backscattered received signals based on the relationship between the statistical decision quantifier and the decision threshold.

24. A backscattering Internet of Things communication device, characterized in that: Applications in receivers include: a second receiving module, configured to receive a baseband signal based on a primary link channel and a plurality of backscattered received signals based on a plurality of secondary link channels, wherein the baseband signal corresponds to a downlink signal of a primary transmitter, the backscattered received signals correspond to backscattered signals of a backscattering device, and the backscattered received signals are represented based on high-level bits and low-level bits; a cancellation module, configured to cancel interference of the primary link channel based on a channel estimation operation, wherein a source signal is obtained by performing minimum distance decoding based on the primary link channel, the baseband signal, and a received joint data signal; an interference signal is determined based on the source signal; the joint data signal is determined based on the baseband signal, the backscattered received signal, and Gaussian white noise received within each second signal period of a channel coherence time interval; and the interference signal is canceled from the joint data signal to obtain a corresponding device received signal; and A calculation module is used to use the device received signal as a numerator and the square root of the signal power of the downlink signal, the product of the source signal and the reflection coefficient of the backscattering device as a denominator to obtain an intermediate variable, decode all intermediate variables within the second signal period to recover the key test statistic of the backscattered received signal, adjust the key test statistic based on the cumulative estimation error of the main link channel to obtain a test statistic, construct a first probability density function and a second probability density function based on the test statistics corresponding to the high-level bit and the low-level bit, respectively, perform maximum likelihood estimation based on the first probability density function and the second probability density function to obtain corresponding first and second means, construct a statistical decision quantile for each of the backscattering devices based on the difference between the first mean and the second mean and the test statistic; construct a decision threshold based on the relationship between the first mean and the second mean; and recover the baseband signal and the multiple backscattered received signals based on the relationship between the statistical decision quantile and the decision threshold.

25. A network device, characterized in that: include: processor; as well as a memory for storing executable instructions of the processor; The processor is configured to execute the backscattering Internet of Things communication method according to claim 11 or 12, or the backscattering Internet of Things communication method according to any one of claims 13 to 22, by executing the executable instructions.

26. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the backscattering Internet of Things communication method according to any one of claims 11 to 22 is implemented.

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