Backscatter communication method and device

Abstract

The embodiment of the present application provides a backscattering method and device, the method comprising: a network device sends an excitation signal to a tag device, the excitation signal comprises a first sub-excitation signal and a second sub-excitation signal, the second sub-excitation signal occupies the same time as the first sub-excitation signal, and the phase of some symbols in the second sub-excitation signal is different from that of some symbols in the first sub-excitation signal; the network device receives an uplink signal, the uplink signal is an uplink reflection signal sent by the tag device after being transmitted through a channel, wherein the uplink reflection signal comprises a first sub-uplink reflection signal and a second sub-uplink reflection signal, the first sub-uplink reflection signal is obtained by multiplying the tag information by the first sub-excitation signal, and the second sub-uplink reflection signal is obtained by multiplying the tag information by the second sub-excitation signal; the network device performs diversity reception on the uplink signal in response to the received uplink signal. The present application can effectively improve the success rate of signal reception.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of communications, and in particular to a backscatter communication method and device. Background Art

[0002] In existing back reflection application scenarios, the distance between the base station and the tag device is usually 20 meters to 30 meters. However, with the diversification of back reflection application scenarios, based on communication needs, the distance between the base station and the tag device is gradually increasing, for example, to 500 meters or 1 kilometer. In the scenario of long-distance communication, due to the transmission bottleneck of the tag device or the limitation of external interference, the uplink signal reflected by the tag device received by the base station may have a high error rate. Summary of the invention

[0003] The present application provides a backscatter communication method and device, which can improve the reception accuracy of network equipment to a certain extent.

[0004] In order to achieve the above objectives, this application adopts the following technical solutions:

[0005] In a first aspect, an embodiment of the present application provides a backscatter communication method, the method comprising: a network device sends an excitation signal to a tag device, wherein the excitation signal comprises a first sub-excitation signal and a second sub-excitation signal, the second sub-excitation signal occupies the same time as the first sub-excitation signal, and the phase of some symbols in the second sub-excitation signal is different from that of some symbols in the first sub-excitation signal. The network device receives an uplink signal, which is an uplink reflection signal sent by the tag device after being transmitted through a channel, wherein the uplink reflection signal comprises a first sub-uplink reflection signal and a second sub-uplink reflection signal, the first sub-uplink reflection signal is obtained by multiplying the tag information by the first sub-excitation signal, and the second sub-uplink reflection signal is obtained by multiplying the tag information by the second sub-excitation signal. Then, the network device performs diversity reception on the uplink signal in response to the received uplink signal.

[0006] Based on the above method, an uplink reflected signal generated based on an excitation signal with a phase shift characteristic is realized, and a cyclic shift can be realized on a frequency domain sequence, thereby increasing the power corresponding to the symbol of the label information received by the network device, so as to improve the reliability of signal transmission and the reception accuracy.

[0007] In a possible implementation, the first sub-excitation signal s1(t) is:

[0008] s1(t)=cos(2πf(t-nT)+φ0)

[0009] The second sub-excitation signal s2(t) is:

[0010] s2(t)=cos(2πf(t-nT)+φ0+φ n )

[0011] Wherein, T is the time length occupied by the symbol in the tag information, N is the number of symbols in the tag information, n=0...N-1, t=(n-1)T...nT, f is the carrier frequency, φ O is the initial phase, φ n is the phase of the nth symbol of the second sub-excitation signal s2(t). Based on the above method, the phase shift characteristic of the excitation signal is realized.

[0012] In a possible implementation, when n in the second sub-excitation signal s2(t) is an even number, φ n =0, when n is an odd number, φ n =π; or, when n in the second sub-excitation signal s2(t) is an even number, φ n =π, when n is an odd number, φ n =0.

[0013] Based on the above method, modulation of the second sub-excitation signal with a phase sequence of [1, -1 . . . 1, -1] is achieved.

[0014] In a possible implementation, when n=4k in the second sub-excitation signal s2(t), φ n =0; when n=4k+1, When n=4k+2, φ n =π; when n = 4k + 3, in, Based on the above method, modulation of the second sub-excitation signal with a phase sequence of [1, j, -1, -j . . . -1, -j] is achieved.

[0015] In a possible implementation, when n=4k in the second sub-excitation signal, φ n =0, n=4k+1, When n=4k+2, φ n =π; when n = 4k + 3, in, Based on the above method, modulation of the second sub-excitation signal with a phase sequence of [1, -j, -1, j . . . -1, j] is achieved.

[0016] In one possible implementation, a network device performs diversity reception on an uplink signal, including: performing a frequency domain transform on the uplink signal to obtain an uplink frequency domain sequence, wherein the uplink frequency domain sequence includes a first frequency domain sequence and a second frequency domain sequence, the first frequency domain sequence is a frequency domain sequence corresponding to a first sub-uplink reflection signal, and the second frequency domain sequence is a frequency domain sequence corresponding to a second sub-uplink reflection signal, wherein the second frequency domain sequence is a cyclic shift sequence of the first frequency domain sequence; obtaining a first frequency domain component of a symbol in the label information on the first frequency domain sequence, and a second frequency domain component of a symbol in the label information on the second frequency domain sequence; and obtaining a frequency domain component of the symbol in the label information based on the first frequency domain component and the second frequency domain component.

[0017] Based on the above method, the network device can achieve diversity reception of tag information and repeated tag information, which can effectively improve the reception accuracy of each symbol of the tag information.

[0018] In a possible implementation, the first frequency domain sequence for:

[0019]

[0020] Among them, h f (k) is the channel response on the kth subcarrier, The frequency domain sequence is obtained by performing frequency domain transformation on the first sub-uplink reflected signal. Based on the above method, the frequency domain transformation process in the diversity reception process is realized.

[0021] In a possible implementation, the second uplink sub-reflection signal for:

[0022]

[0023] Among them, h f (k) is the channel response on the kth subcarrier, The second sub-uplink reflected signal The frequency domain sequence obtained by frequency domain transformation is: is the phase sequence corresponding to the second sub-excitation signal, x(n) is the label information, Represents the frequency domain sequence corresponding to the first sub-uplink reflected signal Perform integer remainder, N is the number of symbols in the tag information x(n), k=0, ..., N-1, ΔN is an integer greater than 0 and less than or equal to N-1. Based on the above method, the frequency domain transformation process in the diversity reception process is realized.

[0024] In a possible implementation manner, before sending the excitation signal, the network device further includes: sending an indication signal to the tag device, where the indication signal is used to instruct the tag device to send an uplink reflection signal.

[0025] Based on the above method, the network device can instruct the tag device to send the information it needs through the instruction signal, for example, the identification information of the tag device or the data of the sensor connected to the tag device.

[0026] In a second aspect, an embodiment of the present application provides a backscatter communication method, the method comprising: a tag device receives an excitation signal sent by a network device, the excitation signal comprising a first sub-excitation signal and a second sub-excitation signal, the second sub-excitation signal and the first sub-excitation signal occupy the same time, and some symbols in the second sub-excitation signal have different phases from some symbols in the first sub-excitation signal; the tag device generates an uplink reflection signal in response to the received excitation signal; wherein the uplink reflection signal comprises a first sub-uplink reflection signal and a second sub-uplink reflection signal, the first sub-uplink reflection signal is obtained by multiplying the tag information by the first sub-excitation signal, and the second sub-uplink reflection signal is obtained by multiplying the tag information by the second sub-excitation signal; the tag device sends the uplink reflection signal to the network device.

[0027] Based on the above method, it is realized that the tag device can send repeated tag information to the network device by modulating the excitation signal with a phase shift characteristic, and based on the phase shift characteristic of the excitation signal, the repeated tag information can be cyclically shifted on the frequency domain sequence, so that the power corresponding to the symbol of the tag information received by the network device is increased, so as to improve the reliability of signal transmission and the reception accuracy.

[0028] In a possible implementation, the first sub-excitation signal s1(t) is:

[0029] s1(t)=cos(2πf(t-nT)+φ0)

[0030] The second sub-excitation signal s2(t) is:

[0031] s2(t)=cos(2πf(t-nT)+φ0+φ n )

[0032] Wherein, T is the time length occupied by the symbol in the tag information, N is the number of symbols in the tag information, n=0...N-1, t=(n-1)T...nT, f is the carrier frequency, φ O is the initial phase, φ n is the phase of the nth symbol of the second sub-excitation signal s2(t).

[0033] In a possible implementation, when n in the second sub-excitation signal s2(t) is an even number, φ n =0, when n is an odd number, φ n =π; or, when n in the second sub-excitation signal s2(t) is an even number, φ n =π, when n is an odd number, φ n =0.

[0034] In a possible implementation, when n=4k in the second sub-excitation signal s2(t), φ n =0; when n=4k+1, When n=4k+2, φ n =π; when n = 4k + 3, in,

[0035] In a possible implementation, when n=4k in the second sub-excitation signal, φ n =0, n=4k+1, When n=4k+2, φ n =π; when n = 4k + 3, in,

[0036] In one possible implementation, the tag device also includes an antenna, a first load, and a second load. The tag device responds to the received excitation signal and, based on the symbol in the tag information, terminates the antenna to the first load or the second load, wherein the antenna is terminated to the first load so that the tag device is in an absorbing state, and the antenna is terminated to the second load so that the tag device is in a reflecting state.

[0037] In a possible implementation, the tag device receives an instruction signal sent by the network device, where the instruction signal is used to instruct the tag device to send an uplink reflected signal.

[0038] In a third aspect, an embodiment of the present application provides a network device, including a processor, a memory and a transceiver, wherein the processor, the memory and the transceiver are coupled, the memory is used to store program instructions, and the program instructions are configured to be executed by the processor; the transceiver is used to send an excitation signal to the tag device, the excitation signal includes a first sub-excitation signal and a second sub-excitation signal, the second sub-excitation signal and the first sub-excitation signal occupy the same time, and the phase of some symbols in the second sub-excitation signal is different from that of some symbols in the first sub-excitation signal; the transceiver is also used to receive an uplink signal, the uplink signal is an uplink reflection signal sent by the tag device after being transmitted through a channel, wherein the uplink reflection signal includes a first sub-uplink reflection signal and a second sub-uplink reflection signal, the first sub-uplink reflection signal is obtained by multiplying the tag information by the first sub-excitation signal, and the second sub-uplink reflection signal is obtained by multiplying the tag information by the second sub-excitation signal; the processor is used to perform diversity reception on the uplink signal in response to the received uplink signal.

[0039] In a fourth aspect, an embodiment of the present application provides a tag device, comprising a transceiver, which is used to receive an excitation signal sent by a network device, the excitation signal comprising a first sub-excitation signal and a second sub-excitation signal, the second sub-excitation signal and the first sub-excitation signal occupy the same time, and some symbols in the second sub-excitation signal have different phases from some symbols in the first sub-excitation signal; the transceiver is also used to send an uplink reflection signal in response to the received excitation signal; wherein the uplink reflection signal comprises a first sub-uplink reflection signal and a second sub-uplink reflection signal, the first sub-uplink reflection signal is obtained by multiplying the tag information by the first sub-excitation signal, and the second sub-uplink reflection signal is obtained by multiplying the tag information by the second sub-excitation signal.

[0040] In a fifth aspect, an embodiment of the present application provides a network device, comprising a processor and a memory, wherein the memory and the processor are coupled, the memory stores program instructions, and the program instructions are executed by the processor, so that the network device executes the method in the first aspect or any possible implementation of the first aspect.

[0041] In a sixth aspect, an embodiment of the present application provides a tag device, including a processor and a memory, wherein the memory and the processor are coupled, the memory stores program instructions, and the program instructions are executed by the processor, so that the tag device executes the method in the second aspect or any possible implementation of the second aspect.

[0042] In the seventh aspect, an embodiment of the present application provides a network device, including a transceiver module and a processing module, wherein the transceiver module is used to send an excitation signal to a tag device, the excitation signal including a first sub-excitation signal and a second sub-excitation signal, the second sub-excitation signal and the first sub-excitation signal occupy the same time, and some symbols in the second sub-excitation signal have different phases from some symbols in the first sub-excitation signal; the transceiver module is also used to receive an uplink signal, the uplink signal is an uplink reflection signal sent by the tag device obtained after channel transmission, wherein the uplink reflection signal includes a first sub-uplink reflection signal and a second sub-uplink reflection signal, the first sub-uplink reflection signal is obtained by multiplying the tag information by the first sub-excitation signal, and the second sub-uplink reflection signal is obtained by multiplying the tag information by the second sub-excitation signal; the processing module is used to perform diversity reception on the uplink signal in response to the received uplink signal.

[0043] In an eighth aspect, an embodiment of the present application provides a tag device, comprising a transceiver module, the transceiver module being used to receive an excitation signal sent by a network device, the excitation signal comprising a first sub-excitation signal and a second sub-excitation signal, the second sub-excitation signal and the first sub-excitation signal occupy the same time, and some symbols in the second sub-excitation signal have different phases from some symbols in the first sub-excitation signal; the transceiver module is also used to send an uplink reflection signal in response to the received excitation signal; wherein the uplink reflection signal comprises a first sub-uplink reflection signal and a second sub-uplink reflection signal, the first sub-uplink reflection signal being obtained by multiplying the tag information by the first sub-excitation signal, and the second sub-uplink reflection signal being obtained by multiplying the tag information by the second sub-excitation signal.

[0044] In a ninth aspect, an embodiment of the present application provides a computer-readable medium for storing a computer program, wherein the computer program includes instructions for executing the method in the first aspect or any possible implementation of the first aspect.

[0045] In a tenth aspect, an embodiment of the present application provides a computer-readable medium for storing a computer program, wherein the computer program includes instructions for executing the method in the second aspect or any possible implementation of the second aspect.

[0046] In an eleventh aspect, an embodiment of the present application provides a computer program comprising instructions for executing the method in the first aspect or any possible implementation of the first aspect.

[0047] In a twelfth aspect, an embodiment of the present application provides a computer program comprising instructions for executing the method in the second aspect or any possible implementation of the second aspect.

[0048] In a thirteenth aspect, an embodiment of the present application provides a chip, the chip comprising a processing circuit and a transceiver pin, wherein the transceiver pin and the processing circuit communicate with each other through an internal connection path, and the processing circuit executes the method in the first aspect or any possible implementation of the first aspect to control the receiving pin to receive a signal and control the sending pin to send a signal.

[0049] In a fourteenth aspect, an embodiment of the present application provides a chip, the chip comprising a processing circuit and a transceiver pin, wherein the transceiver pin and the processing circuit communicate with each other through an internal connection path, and the processing circuit executes the method in the second aspect or any possible implementation of the second aspect to control the receiving pin to receive a signal, and to control the sending pin to send a signal.

[0050] In a fifteenth aspect, an embodiment of the present application provides a communication system, which includes the network device and label device involved in the first and second aspects above. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0052] Figure 1a A schematic diagram of an application scenario provided for an embodiment of the present application;

[0053] Figure 1b A schematic diagram of an application scenario provided for an embodiment of the present application;

[0054] Figure 2 is a schematic diagram of the structure of a network device shown as an example;

[0055] Figure 3 is a schematic diagram of an exemplary backscatter communication process;

[0056] Figure 4 is a schematic diagram showing an exemplary method of generating an indication signal;

[0057] Figure 5 is a schematic diagram of an exemplary backscatter communication process;

[0058] Figure 6 is a schematic diagram of the structure of a label device shown as an example;

[0059] Figure 7 is a schematic diagram of an exemplary signal modulation method;

[0060] Figure 8 A schematic diagram of a flow chart of a backscatter communication method provided in an embodiment of the present application;

[0061] Fig. 9 is a schematic diagram of a second sub-excitation signal shown as an example;

[0062] Fig.10 is a schematic diagram of a second sub-excitation signal shown as an example;

[0063] Fig.11 is a schematic diagram of a second sub-excitation signal shown as an example;

[0064] Fig.12 is a schematic diagram of an exemplary cyclic shift;

[0065] Fig.13 is a schematic diagram of an exemplary cyclic shift;

[0066] Fig.14 is a schematic diagram of an exemplary cyclic shift;

[0067] Fig.15 The effect diagram is shown as an example;

[0068] Fig.16 A schematic diagram of a flow chart of a backscatter communication method provided in an embodiment of the present application;

[0069] Fig.17 is a schematic diagram of an uplink reflected signal shown as an example;

[0070] Fig.18a is a schematic diagram showing an exemplary generation of a first sub-uplink reflected signal;

[0071] Fig.18b is a schematic diagram showing an exemplary generation of a second sub-uplink reflected signal;

[0072] Fig.19a is a schematic diagram of a first frequency domain sequence shown as an example;

[0073] Fig.19b is a schematic diagram of a second frequency domain sequence shown as an example;

[0074] Fig. 20 A schematic diagram of a flow chart of a backscatter communication method provided in an embodiment of the present application;

[0075] Fig.21a is a schematic diagram showing an exemplary generation of a first sub-uplink reflected signal;

[0076] Figure 21b is a schematic diagram showing an exemplary generation of a second sub-uplink reflected signal;

[0077] Fig.22a is a schematic diagram of a first frequency domain sequence shown as an example;

[0078] Figure 22b is a schematic diagram of a second frequency domain sequence shown as an example;

[0079] Fig.23 A schematic diagram of a flow chart of a backscatter communication method provided in an embodiment of the present application;

[0080] Fig.24a is a schematic diagram showing an exemplary generation of a first sub-uplink reflected signal;

[0081] Figure 24b is a schematic diagram showing an exemplary generation of a second sub-uplink reflected signal;

[0082] Fig.25a is a schematic diagram of a first frequency domain sequence shown as an example;

[0083] Fig.25b is a schematic diagram of a second frequency domain sequence shown as an example;

[0084] Fig.26 is a schematic diagram of multiple retransmissions shown as an example;

[0085] Fig. 27 A schematic diagram of the structure of a network device provided in an embodiment of the present application;

[0086] Fig.28 A schematic diagram of the structure of a label device provided in an embodiment of the present application;

[0087] Fig.29 A schematic diagram of the structure of a device provided in an embodiment of the present application;

[0088] Fig.30 A schematic diagram of the structure of a chip provided in an embodiment of the present application. DETAILED DESCRIPTION

[0089] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0090] The term "and / or" in this article is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0091] The terms "first" and "second" in the description and claims of the embodiments of the present application are used to distinguish different objects rather than to describe a specific order of objects. For example, a first target object and a second target object are used to distinguish different target objects rather than to describe a specific order of target objects.

[0092] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0093] In the description of the embodiments of the present application, unless otherwise specified, the meaning of "multiple" refers to two or more than two. For example, multiple processing units refer to two or more processing units; multiple systems refer to two or more systems.

[0094] like Figure 1a FIG. 1 is a schematic diagram of an application scenario provided by an embodiment of the present application. The application scenario includes a network device 100 and a tag device 200. Figure 1b The figure shows another application scenario provided by an embodiment of the present application, which includes a network device 100, a relay device 300 and a tag device 200. It should be noted that in actual applications, the number of network devices, tag devices and relay devices can be one or more, and the number of devices in the communication system shown in FIG1 is only an adaptive example, and the present application does not limit this.

[0095] Specifically, Figure 1a and Figure 1b The network device in the description is a device with wireless communication function, which can send radio frequency signals to the tag device and receive radio frequency signals returned by the tag device. The devices can be collectively referred to as network devices.

[0096] Optionally, in the embodiment of the present application, the network device may be an access point, which is mainly deployed in homes, buildings and parks, with a typical coverage radius of tens to hundreds of meters. Of course, it can also be deployed outdoors. The access point is equivalent to a bridge connecting the wired network and the wireless network. Its main function is to connect various wireless network clients together and then connect the wireless network to the Ethernet.

[0097] Specifically, the access point can be a terminal device (such as a mobile phone) or a network device (such as a router) with a wireless fidelity (WiFi) chip. The access point can be a device that supports the 802.11be standard. The access point can also be a device that supports multiple wireless local area networks (WLAN) standards of the 802.11 family, such as 802.11be, 802.11ax, 802.11ac, 802.11n, 802.11g, 802.11b and 802.11a.

[0098] For example, access points and tag devices can be devices used in the Internet of Vehicles, IoT nodes and sensors in the Internet of Things (IoT), smart cameras and smart remote controls in smart homes, smart water and electricity meters, and sensors in smart cities.

[0099] The various aspects of the present application can be extended to other networks using various standards or protocols, for example, BLUETOOTH (Bluetooth), high performance radio LAN (HIPERLAN) (a wireless standard similar to the IEEE802.11 standard, mainly used in Europe) and wide area network (WAN), wireless local area network (WLAN), personal area network (PAN) or other networks known now or developed later. Therefore, regardless of the coverage and wireless access protocol used, the various aspects provided by the present application can be applied to any suitable wireless network.

[0100] Optionally, in an embodiment of the present application, the network device may also be a base station in a fifth-generation 5G communication system, a base station in a future communication system, etc.

[0101] For example, Figure 2 The following is a schematic diagram of the structure when the network device is a base station. Figure 2 , the base station 400 includes at least one processor 401, at least one memory 402, at least one transceiver 403, at least one network interface 404 and one or more antennas 405. The processor 401, the memory 402, the transceiver 403 and the network interface 404 are connected, for example, through a bus. The antenna 405 is connected to the transceiver 403. The network interface 404 is used to connect the base station to other communication devices through a communication link. In the embodiment of the present application, the connection may include various interfaces, transmission lines or buses, etc., which are not limited in this embodiment.

[0102] The processor in the embodiment of the present application, such as processor 401, may include at least one of the following types: a general-purpose central processing unit (CPU), a digital signal processor (DSP), a microprocessor, an application-specific integrated circuit (ASIC), a microcontroller unit (MCU), a field programmable gate array (FPGA), or an integrated circuit for implementing logical operations. For example, processor 401 may be a single-core (single-CPU) processor or a multi-core (multi-CPU) processor. At least one processor 401 may be integrated in one chip or located on multiple different chips.

[0103] The memory in the embodiment of the present application, such as memory 402, may include at least one of the following types: read-only memory (ROM) or other types of static storage devices that can store static information and instructions, random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, and may also be electrically erasable programmable read-only memory (EEPROM). In some scenarios, the memory may also be a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto.

[0104] The memory 402 may be independent and connected to the processor 401. Optionally, the memory 402 may also be integrated with the processor 401, for example, integrated into a chip. Among them, the memory 402 can store program codes for executing the technical solutions of the embodiments of the present application, and the execution is controlled by the processor 401, and the various types of computer program codes executed may also be regarded as drivers of the processor 401. For example, the processor 401 is used to execute the computer program codes stored in the memory 402, so as to implement the technical solutions in the embodiments of the present application. Optionally, the memory 402 may also be connected to the processor 401 through an interface outside the chip.

[0105] The transceiver 403 can be used to support the reception or transmission of radio frequency signals between the base station and the tag device, and the transceiver 403 can be connected to the antenna 405. The transceiver 403 includes a transmitter Tx and a receiver Rx. Specifically, one or more antennas 405 can receive radio frequency signals, for example, uplink reflection signals sent by the tag device 200, and the receiver Rx of the transceiver 403 is used to receive the radio frequency signal from the antenna, and convert the radio frequency signal into a digital baseband signal or a digital intermediate frequency signal, and provide the digital baseband signal or the digital intermediate frequency signal to the processor 401, so that the processor 401 further processes the digital baseband signal or the digital intermediate frequency signal, such as demodulation and decoding. In addition, the transmitter Tx in the transceiver 403 is also used to receive a modulated digital baseband signal or a digital intermediate frequency signal from the processor 401, and convert the modulated digital baseband signal or the digital intermediate frequency signal into a radio frequency signal, and send the radio frequency signal through one or more antennas 405, such as the indication signal and the excitation signal in the embodiment of the present application. Specifically, the receiver Rx can selectively perform one or more stages of down-mixing and analog-to-digital conversion processing on the RF signal to obtain a digital baseband signal or a digital intermediate frequency signal, and the order of the down-mixing and analog-to-digital conversion processing is adjustable. The transmitter Tx can selectively perform one or more stages of up-mixing and digital-to-analog conversion processing on the modulated digital baseband signal or digital intermediate frequency signal to obtain a RF signal, and the order of the up-mixing and digital-to-analog conversion processing is adjustable. The digital baseband signal and the digital intermediate frequency signal can be collectively referred to as a digital signal.

[0106] In the present application, the device implementing the aforementioned method embodiment may be a chip or a processing system. For example, the device may include only Figure 2 Some of the components shown, for example, only include a processor 401, and the processor 401 is coupled and linked with a memory 402, so that a device equipped with the chip or processing system executes the method of the embodiment of the present application.

[0107] Optionally, the apparatus for implementing the aforementioned method embodiment may also be a complete device, such as including a processor 401, a transceiver 403, and a memory 402. Optionally, the network device may also include input and output devices, such as a display screen, a keyboard, etc.

[0108] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present application, Figure 1a , a brief description is given of the backscatter communication method in the prior art.

[0109] Backscatter technology is a technology that can be applied to low-cost, low-power systems. Unlike terminals in traditional communication technologies, the tag device in backscatter technology cannot generate radio frequency signals by itself. It modulates the radio frequency signals in the environment to send tag information. For example, the radio frequency signals in the environment include wireless TV signals, broadcast signals, signals sent by mobile communication stations, signals sent by routers, signals sent by dedicated card readers, etc.

[0110] Specifically, Figure 3 As shown, a network device (e.g., network device 100) sends an indication signal to a tag device (e.g., tag device 200), and the indication signal carries indication information for instructing the tag device to send (or reflect) an uplink reflection signal based on an excitation signal. The indication signal is obtained by modulating a carrier signal based on the indication information by the network device.

[0111] For example, Figure 4 The diagram shows a method for generating an indication signal. Specifically, the network device generates a carrier signal c(t), which is a sinusoidal wave signal. Subsequently, the network device can modulate the carrier signal based on the indication information x(n) to be sent to obtain the indication signal. For example, taking OOK (On-Off Keying, binary on-off keying) modulation as an example, assuming that the indication information is [1, 0, 1], the indication signal is the product of the carrier signal c(t) and the indication information [1, 0, 1], which can be expressed as c(t)*x(n).

[0112] After receiving the indication signal, the tag device determines that it needs to feed back the tag information to the network device. As mentioned above, the tag device itself cannot generate a radio frequency signal, and can only modulate the excitation signal sent by the network device to feed back the tag information to the network device.

[0113] Specifically, Figure 5 As shown, after the network device sends the indication signal, it can send an excitation signal s(t) to the tag device.

[0114] After receiving the excitation signal, the tag device may modulate the excitation signal s(t) according to the tag information to be sent to obtain an uplink reflection signal x(t), and send the uplink reflection signal x(t) to the network device.

[0115] The following is a detailed description of the backscattering principle of the tag device, specifically:

[0116] like Figure 6 The figure shows a schematic diagram of the structure of a label device. Figure 6 ,The tag device includes an antenna and multiple loads, e.g. Figure 6 The load Z1 and the load Z2 in the tag device. Optionally, the tag device also includes a microprocessor for controlling the antenna to be terminated at different loads to generate an uplink reflection signal. Optionally, the tag device may also include a memory, which may be independent and connected to the microprocessor. Optionally, the memory may also be integrated with the microprocessor, for example, integrated into a chip. The memory may be used to store program instructions. When the program instructions are executed by the microprocessor, the tag device may be controlled to execute the method in the present application. The memory may also be used to store the tag information described in the present application. The microprocessor may modulate the excitation signal received through the antenna based on the tag information in the memory.

[0117] Taking OOK modulation as an example, assuming that the excitation signal received by the tag device through the antenna is s(t), and the generated uplink reflection signal is x(t), the relationship between the two can be expressed as:

[0118] x(t)=Γ.s(t) (1)

[0119] Where Γ is the reflection coefficient, which can be expressed as: Where Z a is the impedance of the antenna, usually 50Ω, Z i is the matching impedance when the tag device is in the i-th state, such as Figure 6 Z1 and Z2 in .

[0120] Based on the above assumptions, the tag device can send "0" and "1" signals in the following ways:

[0121] If the tag device needs to send a "0" signal, the tag device can select The reflection coefficient Γ=0, so that the energy of the excitation signal is absorbed. At this time, the tag device does not send a signal. It can be understood that the tag device is in an absorption state, or called an OFF state.

[0122] If the tag device needs to send a "1" signal, the tag device can select The reflection coefficient Γ≠0, so that the energy of the excitation signal is reflected. At this time, the tag device is sending a signal. It can be understood that the tag device is in a reflection state, or called an ON state.

[0123] For example, Figure 7 Taking the modulation mode shown as an example, specifically, the tag information to be sent by the tag device is x(n), and the excitation signal received by the tag device is s(t), and the excitation signal s(t) is a sine wave signal. For example, assuming that the tag information is [1, 0, 1], the tag device can change the impedance matching state of the antenna based on the modulation symbol in the tag information, that is, control different loads terminated by the antenna, and the generated uplink reflection signal x(t) can be expressed as:

[0124] x(t)=s(t)×x(n) (2)

[0125] In traditional backscatter communication systems, the distance between network devices and tag devices is usually between 20 meters and 30 meters. However, with the evolution of backscatter communication systems and changes in demand, the transmission distance requirements between network devices and tag devices are gradually increasing, such as the transmission distance increased to 500 meters or 1 kilometer. In the scenario where the transmission distance increases, due to limiting factors such as the power and power consumption of the tag device, the network device cannot receive the uplink reflected signal x(t) sent by the tag device, or the signal reception error rate is high.

[0126] To solve the above problems, the prior art proposes a retransmission method, which may also be called a repeated coding method. This method improves the reception success rate by repeatedly sending label information. However, the improvement effect of this method is limited. The specific reasons will be described in detail in the following embodiments.

[0127] In view of the problems in the prior art, the present application proposes a backscatter communication method, in which an excitation signal with a phase shift characteristic is sent to a tag device through a network device, so that when the tag device repeatedly sends tag information, the signal part corresponding to the repeatedly sent tag information in the uplink reflection signal is cyclically shifted in the frequency domain. The network device can receive the uplink reflection signal sent by the tag device in a diversity reception manner, thereby improving the reception success rate.

[0128] In the present application, based on different excitation signals s(t), the cyclic shifting mode of the signal part corresponding to the repeatedly transmitted label information in the uplink reflected signal x(t) in the frequency domain is also different. In one example, the signal corresponding to the repeatedly transmitted label information (hereinafter referred to as repeated label information) in the uplink reflected signal x(t) can achieve N / 2 cyclic shift in the frequency domain, where N is the number of modulated signals in the label information. For details, please refer to Scenario 2.

[0129] In another example, the signal corresponding to the repeated label information in the uplink reflected signal x(t) can achieve N / 4 cyclic left shift in the frequency domain. For details, please refer to scenario three.

[0130] In another example, the signal x(t) in the uplink reflected signal corresponding to the repeated label information can achieve 3N / 4 cyclic left shift in the frequency domain. For details, please refer to scenario four.

[0131] Combine the following Figure 1a The backscatter communication method of the present application is described in detail. Figure 8 FIG. 1 is a flow chart of a backscatter communication method in an embodiment of the present application. Figure 8 middle:

[0132] Step 101: A network device sends an excitation signal to a tag device, wherein the excitation signal includes a first sub-excitation signal and a second sub-excitation signal, the second sub-excitation signal occupies the same time as the first sub-excitation signal, and some symbols in the second sub-excitation signal have different phases from some symbols in the first sub-excitation signal.

[0133] Specifically, in this application, a network device (such as Figure 1a The network device 100 in FIG. 1 sends an excitation signal s(t) to the tag device. The function of the excitation signal s(t) is as described above, and the tag device can modulate the excitation signal s(t) according to the tag information x(n) to generate an uplink reflection signal x(t).

[0134] In the present application, the excitation signal s(t) includes a first sub-excitation signal s1(t) and a second sub-excitation signal s2(t). Exemplarily, the first sub-excitation signal s1(t) is a cosine wave signal, which can be expressed as:

[0135] s1(t)=cos(2πf(t-nT)+φ0) (3)

[0137] The second sub-excitation signal s2(t) can be expressed as:

[0138] s2(t)=cos(2πf(t-nT)+φ0+φ n ) (4)

[0139] Wherein, T is the time length occupied by each modulation symbol in the tag information x(n), N is the number of modulation symbols included in the tag information x(n), n=0...N-1, f is the carrier frequency, φ O is the initial phase, φ n is the phase of the nth symbol of the second sub-excitation signal s2(t), t=(n-1)T...nT.

[0140] The following is a detailed description of the above parameters:

[0141] In the present application, the label information x(n) may include N modulation symbols, which may also be referred to as uplink modulation symbols. For example, the label information x(n) may be [1, 0, 1, 1], where each number represents a modulation symbol, that is, in this example, N=4.

[0142] Exemplarily, the time length corresponding to each modulation symbol in the label information x(n) is T, that is, the time length corresponding to the label information x(n) is N*T. Still taking the label information x(n) as [1, 0, 1, 1] as an example, in this example, the time length corresponding to the label information x(n) is 4T.

[0143] In one possible implementation, the network device has already known in advance the number of modulation symbols contained in the tag information x(n) to be sent by the tag device each time. That is, when the network device sends the excitation signal s(t), it can determine that the time length occupied by the first sub-excitation signal s1(t) and the second sub-excitation signal s2(t) is equal to the time length corresponding to the tag information x(n), specifically, the time length corresponding to all modulation symbols included in the tag information x(n), that is, N*T.

[0144] Exemplarily, the way in which the network device obtains the length of the tag information x(n) in advance can be that the network device and the tag device negotiate in advance, or the network device and the tag device are both configured with transmission length rules. For example, the number of modulation symbols contained in the tag information x(n) transmitted by the tag device each time is 4, that is, N=4. The specific occupied time can be set according to actual conditions, and this application does not limit this.

[0145] In this application, the carrier frequency f and the initial phase φ O It can be set according to actual needs and this application does not limit it.

[0146] In this application, φ n is the phase of the nth symbol of the second sub-excitation signal s2(t), that is, based on φ n The sign of the second sub-excitation signal s2(t) changes with the value of φ n The value of is changed so that the phase of some symbols of the second sub-excitation signal s2(t) is different from that of some symbols of the first sub-excitation signal s1(t).

[0147] Optionally, the second sub-excitation signal s2(t) can also be understood as the first sub-excitation signal s1(t) multiplied by the phase shift signal, so that the phase sequence corresponding to the second sub-excitation signal s2(t) is opposite in polarity to a partial sequence in the phase sequence corresponding to the first sub-excitation signal s1(t).

[0148] For example, assuming that the phase sequence corresponding to the first sub-excitation signal s1(t) is [1, 1, 1, 1], and the phase sequence corresponding to the second sub-excitation signal s2(t) is [1, -1, 1, -1]. In this example, the second sub-excitation signal s2(t) can be regarded as the first sub-excitation signal s1(t) multiplied by the phase shift signal, wherein the phase sequence corresponding to the phase shift signal is [1, -1, 1, -1], so that the phase corresponding to the odd-numbered bit symbols of the second sub-excitation signal s2(t) is opposite to the phase corresponding to the odd-numbered bit symbols of the first sub-excitation signal s1(t). It can also be understood that the odd bits of the phase sequence corresponding to the second sub-excitation signal s2(t) have opposite polarity to the odd bits of the phase sequence of the first sub-excitation signal s1(t).

[0149] The following is n The different values ​​of are described in detail:

[0150] In one example, when n in the second sub-excitation signal s2(t) is an even number, φ n =0, when n is an odd number, φ n =π, or, when n in the second sub-excitation signal s2(t) is an even number, φ n =π, when n is an odd number, φ n =0. In this example, the phase sequence corresponding to the second sub-excitation signal s2(t) is [1, -1...1, -1]. It can be understood that the second sub-excitation signal s2(t) is obtained by multiplying the first sub-excitation signal s1(t) by the phase shift signal with a phase sequence of [1, -1...1, -1]. For example, taking the second sub-excitation signal s2(t) including 4 symbols as an example, the second sub-excitation signal s2(t) is as follows: Fig. 9 As shown, the corresponding phase sequence is [1, -1, 1, -1]. Accordingly, the second uplink sub-reflected signal x2(t) generated based on the second sub-excitation signal s2(t) can achieve N / 2 cyclic shift in the frequency domain, and the specific details will be described in detail in Scenario 2.

[0151] In another example, when n=4k in the second sub-excitation signal s2(t), φ n =0; when n=4k+1, When n=4k+2, φ n =π; when n = 4k + 3, In this example, the phase sequence corresponding to the second sub-excitation signal s2(t) is [1, j, -1, -j...1, j, -1, -j]. It can be understood that the second sub-excitation signal s2(t) is the product of the first sub-excitation signal s1(t) and the phase shift signal with a phase sequence of [1, j, -1, -j...1, j, -1, -j]. Where k is For example, still taking the second sub-excitation signal s2(t) including 4 symbols as an example, the second sub-excitation signal s2(t) is as follows: Fig.10 As shown, the corresponding phase sequence is [1, j, -1, -j]. Accordingly, the second sub-uplink reflected signal x2(t) generated based on the second sub-excitation signal s2(t) can achieve N / 4 cyclic left shift in the frequency domain, and the specific details will be described in detail in scenario three.

[0152] In another example, when n=4k in the second sub-excitation signal s2(t), φ n =0, n=4k+1, When n=4k+2, φ n =π; when n = 4k + 3, Among them, k is In this example, the phase sequence corresponding to the second sub-excitation signal s2(t) is [1, -j, -1, j...1, -j, -1, j]. It can be understood that the second sub-excitation signal s2(t) is obtained by multiplying the first sub-excitation signal s1(t) by a phase shift signal having a phase sequence of [1, -j, -1, j...1, -j, -1, j]. For example, still taking the second sub-excitation signal s2(t) including 4 symbols as an example, the second sub-excitation signal s2(t) is as follows: Fig.11 As shown, the corresponding phase sequence is [[1, -j, -1, j]. Accordingly, the second sub-uplink reflected signal x2(t) generated based on the second sub-excitation signal s2(t) can achieve 3N / 4 cyclic left shift in the frequency domain, and the specific details will be described in detail in scenario four.

[0153] In a possible implementation, before step 101, the network device may send an indication signal to the tag device to instruct the tag device to send an uplink reflection signal. The method for generating the indication signal may refer to the above and will not be described in detail here.

[0154] In another possible implementation, the network device may send one or more excitation signals, and the phase shift characteristics of the second excitation signal in each excitation signal may be the same or different. Accordingly, the tag device may send multiple tag information based on the one or more excitation signals, wherein the multiple tag information are different tag information.

[0155] Step 102: The tag device generates an uplink reflection signal in response to the received excitation signal sent by the network device, wherein the uplink reflection signal includes a first sub-uplink reflection signal and a second sub-uplink reflection signal, the first sub-uplink reflection signal is obtained by multiplying the tag information by the first sub-excitation signal, and the second sub-uplink reflection signal is obtained by multiplying the tag information by the second sub-excitation signal.

[0156] Specifically, in the present application, the tag device receives an excitation signal s(t) sent by the network device, and can modulate the excitation signal s(t) based on the tag information to be sent to generate an uplink reflection signal x(t), which carries the tag information x(n) and repeated tag information x(n).

[0157] Specifically, in order to improve the accuracy of signal reception, the tag device of the present application adopts a method of repeatedly sending tag information. In the present application, repeated sending is taken as an example, that is, the tag device sends tag information twice. Specifically, the tag device adjusts the state of the load connected to the antenna according to at least one modulation symbol contained in the tag information x(n) so that the tag device is in an "absorption" or "reflection" state, thereby realizing the modulation of the excitation signal s(t) to generate an uplink reflection signal x(t).

[0158] Specifically, the tag device modulates the first sub-excitation signal s1(t) according to the tag information x(n) by adjusting the state of the load connected to the antenna to obtain the first sub-uplink reflection signal x1(t). As described above, the modulation in the present application can be understood as the multiplication of two signals. Exemplarily, the first sub-uplink reflection signal x1(t) can be expressed as the multiplication of the first sub-excitation signal s1(t) and the tag information x(n), wherein, since the phase sequence corresponding to the first sub-excitation signal s1(t) in the present application is [1, 1...1, 1], the first self-uplink reflection signal x1(t) = x(n).

[0159] Subsequently, the tag device modulates the second sub-excitation signal s2(t) according to the tag information x(n) by adjusting the state of the load connected to the antenna to obtain the second sub-uplink reflection signal x2(t). Exemplarily, the second sub-uplink reflection signal x2(t) can be expressed as the product of the second sub-excitation signal s2(t) and the tag information x(n).

[0160] The principle of cyclic shift of signals in the frequency domain is described in detail below:

[0161] Specifically, a signal sequence, such as the tag information x(n) in this application, can be obtained based on Fourier transform to obtain the corresponding sequence in the frequency domain:

[0162]

[0163] In the present application, the second uplink sub-reflected signal x2(t) can be expressed as:

[0164]

[0165] Wherein, ΔN is an integer greater than or equal to 0 and less than or equal to N-1, That is the second sub-excitation signal s2(t). It can be seen from formula (6) that the second sub-uplink reflected signal x2(t) is obtained by multiplying the label information x(n) by the phase shift signal. The phase shift signal is the second sub-excitation signal s2(t).

[0166] Based on Fourier transform, the frequency domain sequence corresponding to the second uplink sub-reflected signal x2(t) is obtained as follows:

[0167]

[0168] Pick The mod() integer remainder operation, the frequency domain sequence corresponding to the second sub-uplink reflected signal x2(t) can be expressed as:

[0169]

[0170] In one example, when When x2(t)=x(n)e jπN , the corresponding frequency sequence realizes N / 2 cyclic left shift, when When x2(t)=x(n)e -jπN , the corresponding frequency domain sequence realizes N / 2 cyclic right shift. It should be noted that for N / 2 cyclic shift, the results of left shift and right shift are the same, and the results are Fig.12 As shown, refer to Fig.12 , e jπn The corresponding phase sequence is [1, -1...1, -1]. Specifically, it can be understood that the second sub-uplink reflected signal x2(t) is the phase shift signal e of the label information x(n) and the phase sequence [1, -1...1, -1]. jπn The multiplication results in a cyclic left shift (or right shift) of the frequency domain components corresponding to the 0 to N / 2 symbols of the second uplink sub-reflected signal x2(t). The result is as follows Fig.12 shown.

[0171] In another example, when hour, It can be understood that the second sub-uplink reflected signal x2(t) is the phase shift signal of the label information x(n) and the phase shift sequence [1, j, -1, -j...1, j, -1, -j] The corresponding frequency domain sequence is multiplied by N / 4 cyclic left shift, such as Fig.13 shown.

[0172] In another example, when -hour, It can be understood that the second sub-uplink reflected signal x2(t) is the phase shift signal of the label information x(n) and the phase shift sequence [1, -j, -1, j...1, -j, -1, j] The corresponding frequency domain sequence is multiplied by N / 4 cyclic right shift, such as Fig.14 shown.

[0173] Optionally, the tag information x(n) includes data information and verification information, where the data information is the data (Data) that the tag device actually wants to send. For example, the data information may be identification information of the tag device. The verification information is used to instruct the network device to verify the received data information to detect whether the received data information is correct. For example, the verification information may include the number of modulation symbols contained in the data information, etc. For details, please refer to the embodiments in the prior art, and this application does not limit it.

[0174] Step 103: The tag device sends an uplink reflection signal.

[0175] Specifically, the tag device modulates the first excitation signal s1(t) and the second excitation signal s2(t) in the excitation signal s(t) based on the tag information x(n), and then sends (or reflects) the generated uplink reflection signal x(t) to the network device, wherein the uplink reflection signal x(t) includes a first sub-uplink reflection signal x1(t) and a second sub-uplink reflection signal x2(t).

[0176] Step 104: The network device receives an uplink signal, where the uplink signal is an uplink reflected signal sent by the tag device and is transmitted through a channel.

[0177] Specifically, after the tag device sends the uplink reflection signal x(t), the uplink reflection signal x(t) is transmitted to the network device through the channel.

[0178] Step 105: The network device performs diversity reception on the uplink signal in response to the received uplink signal.

[0179] Specifically, in the present application, after receiving the uplink signal, the network device may perform diversity reception on the uplink signal.

[0180] The process of diversity reception includes:

[0181] The network device performs frequency domain transformation on the uplink signal y(t) to obtain a frequency domain sequence corresponding to the uplink signal y(t). The first frequency domain sequence corresponding to the first uplink sub-reflected signal x1(t) can be expressed as:

[0182]

[0183] The second frequency domain sequence corresponding to the second uplink sub-reflected signal x2(t) can be expressed as:

[0184]

[0185] Among them, h f (k) represents the channel response on the kth subcarrier, is a frequency domain sequence obtained by frequency domain transforming the first uplink sub-reflected signal x1(t). The frequency domain transform process may refer to formula (5) and will not be described in detail here.

[0186] is a frequency domain sequence obtained by frequency domain transforming the second uplink sub-reflected signal x2(t), wherein the frequency domain transform process of the second uplink sub-reflected signal x2(t) may refer to formulas (6) to (8), N is the number of modulation symbols included in the label information x(n), k=0, ..., N-1, and ΔN is an integer greater than 0 and less than or equal to N-1.

[0187] Subsequently, the network device combines the frequency domain components of each modulation symbol included in the label information x(n) on the first frequency domain sequence and the second frequency domain sequence to obtain the frequency domain component corresponding to each modulation symbol. The frequency domain component of the modulation symbol can be expressed as:

[0188]

[0189] Among them, k=0, 1, .., N-1, ()′ represents the conjugation.

[0190] As mentioned above, the retransmission method in the existing technology is only to repeatedly send the label information. For the network equipment, if the channel interference on a certain subcarrier is large, even if the label device repeatedly sends the label information many times, but when the modulation symbol is always located on the subcarrier with large channel interference, the receiving power of the modulation symbol will still be very small, resulting in the corresponding modulation symbol on the subcarrier may be received incorrectly, or even cannot be received.

[0191] In the present application, by utilizing the phase shift characteristics of the excitation signal, the signal in the uplink reflection signal corresponding to the repeated label information, that is, the second sub-uplink reflection signal is cyclically shifted in the frequency domain. During the diversity reception process of the network device, the modulation symbols in the label information correspond to different subcarriers. In other words, when the network device receives the label information twice, the subcarriers corresponding to the modulation symbols in the two transmission processes are different, thereby averaging the power of each modulation symbol and improving the reception success rate.

[0192] The above effects are described in detail with a specific example below: Taking the tag information x(n) as [x1, x2] as an example, in the existing technology, the frequency domain component received by the network device on subcarrier 1 is h1*x1, and the frequency domain component received on subcarrier 2 is h2*x2, h1 is the channel response of subcarrier 1, and h2 is the channel response on subcarrier 2. Assuming h1=0.1, h2=10, even if the tag device sends the tag information twice, the frequency domain component corresponding to x1 is h1*x1+h1*x1=0.2*x1, and the frequency domain component corresponding to x2 is h2*x2+h2*x2=20*x2. It can be seen that after repeated transmission, the received power of x1 is very small, and the power of x2 is very large.

[0193] In the present application, the tag device may send x1 on subcarrier 1 and x2 on subcarrier 2 when sending tag information for the first time, and send x2 on subcarrier 1 and x1 on subcarrier 2 when sending tag information for the second time. That is, when sending for the second time, the frequency domain sequence corresponding to the repeated tag information is shifted by N / 2. The network device combines the frequency domain components of the modulated signals of the tag information received twice in the frequency domain through diversity reception. The frequency domain component corresponding to x1 is h1*x1+h2*x1=10.1*x1, and the frequency domain component corresponding to x2 is h1*x2+h2*x2=10.1*x2. It can be seen that the present application can achieve the averaging of the received power, thereby improving the reception success rate.

[0194] like Fig.15 The figure shows the effect comparison between the prior art and the technical solution of the present application, wherein the horizontal axis is the signal-to-noise ratio (in dB) and the vertical axis is the bit error rate. Fig.15 It can be seen that by adopting the technical solution in this application, the performance is significantly improved compared with the traditional technical solution (i.e., simple retransmission solution), and the gain (referring to the signal-to-noise ratio) can be improved by at least 5dB, that is, under the same bit error rate, the signal-to-noise ratio of this application is smaller.

[0195] In a possible implementation, the tag device in the present application may be an independent device, that is, the tag information transmitted by the tag device is its own data, for example, it may be the identification information of the tag device. For example, the tag device may be a Radio Frequency Identification (RFID) tag. When the RFID tag is used in an IoT application scenario, the tag information may be a license plate number, that is, the tag device may send the license plate number to the network device by modulating the excitation signal. The tag device may also be an unlocking device, such as a smart car key, etc. The corresponding tag information is the unlocking information, or may be called pairing information.

[0196] In one possible implementation, the tag device can be connected to other devices, the tag device can obtain the data to be transmitted from other devices, that is, the tag information, and transmit the data obtained from other devices to the network device based on the technical solution in the present application. For example, the tag device can be connected to a temperature sensor, and the corresponding tag information is the temperature parameter obtained from the temperature sensor.

[0197] In a possible implementation, as described above, the present application can solve the problem of a high error rate in receiving tag information by a network device in a scenario where the distance between the network device and the tag device is far (e.g., 500 meters). Optionally, the present application can be implemented only in a scenario where the distance is far. For example, the network device can set a detection condition. If the detection condition is met, the technical solution of the present application is executed, wherein the detection condition can be that the error rate of receiving tag information is greater than a preset threshold. For example, the preset threshold can be 80%, which can be set based on actual conditions and is not limited by the present application.

[0198] In another possible implementation, the present application may ignore the scenario limitation of distance, that is, it may also be applicable in the scenario where the network device and the tag device are relatively close, and the present application does not make any limitation.

[0199] Several specific embodiments are used below to explain in detail the technical solution of the above method embodiment.

[0200] Scene 2

[0201] In this scenario, a detailed description is given by taking the second uplink sub-reflected signal implementing N / 2 cyclic shift in the frequency domain as an example.

[0202] Combination Figure 1a The communication system shown in Fig.16 FIG. 1 is a flow chart of a backscatter communication method in an embodiment of the present application. Fig.16 middle:

[0203] Step 201: The network device sends an excitation signal to the tag device, wherein the excitation signal includes a first sub-excitation signal and a second sub-excitation signal, the second excitation signal is obtained by multiplying the first excitation signal by a phase shift signal, and the phase sequence corresponding to the phase shift signal is [1, -1, 1, -1].

[0204] Specifically, in this embodiment and the following embodiments, the number of modulation symbols of the tag information x(n) N=4 is taken as an example for description. That is, the time length occupied by the first sub-excitation signal s1(t) and the second sub-excitation signal s2(t) is 4T.

[0205] Based on formula (3) and formula (4), when n in the second sub-excitation signal s2(t) is an even number, φ n=0, when n is an odd number, φ n =π, or, when n in the second sub-excitation signal s2(t) is an even number, φ n =π, when n is an odd number, φ n =0. That is to say, when the value sequence corresponding to φn is [0, π, ... 0, π], or [π, 0, ..., π, 0], when it is substituted into formula (4), the phase sequence corresponding to the second sub-excitation signal s2(t) is [1, -1 ... 1, -1], that is, it can be understood that the second sub-excitation signal s2(t) is the first sub-excitation signal s1(t) multiplied by the phase shift signal with a phase sequence of [1, -1 ... 1, -1]. The schematic diagram of the second sub-excitation signal can be referred to Fig. 9 . Exemplarily, in this embodiment, the time length occupied by the first sub-excitation signal s1(t) and the second sub-excitation signal s2(t) is 4T, the phase sequence corresponding to the first sub-excitation signal s1(t) is [1, 1, 1, 1], and the phase sequence corresponding to the second sub-excitation signal s2(t) is [1, -1, 1, -1].

[0206] For other details, please refer to step 101 and will not be described in detail here.

[0207] Step 202: The tag device generates an uplink reflection signal in response to the received excitation signal sent by the network device, wherein the uplink reflection signal includes a first sub-uplink reflection signal and a second sub-uplink reflection signal, the first sub-uplink reflection signal is obtained by multiplying the tag information by the first sub-excitation signal, and the second sub-uplink reflection signal is obtained by multiplying the tag information by the second sub-excitation signal.

[0208] Exemplarily, in this embodiment, taking the case where the tag device transmits tag information x(n) twice, which can also be understood as repeatedly transmitting tag information once, as an example, the generated uplink reflection signal x(t) is as follows: Fig.17 shown.

[0209] Reference Fig.17 , Data1 and CRC (first CRC) correspond to the first sub-uplink reflected signal x1(t), Data2 and CRC (second CRC) correspond to the second sub-uplink reflected signal x2(t), the pilot (Pilot) is used for synchronization and channel estimation at the receiving end, and the null value (NULL) indicates that the tag device does not send data.

[0210] Combination Fig.17 ,like Fig.18aThe figure shows a schematic diagram of the generation of the first sub-uplink reflected signal x1(n). Specifically, assuming that the label information x(n) is [x(0), x(1), x(2), x(3)], the first sub-uplink reflected signal x1(t) is obtained by multiplying the label information [x(0), x(1), x(2), x(3)] by the first sub-excitation signal s1(t), wherein the phase sequence corresponding to the first sub-excitation signal s1(t) is [1, 1, 1, 1].

[0211] like Fig.18b The figure shows a schematic diagram of the generation of the second sub-uplink reflected signal x2(t). The tag information repeatedly sent by the tag device still contains the modulation symbols [x(0), x(1), x(2), x(3)]. The second sub-uplink reflected signal x2(t) is the product of the tag information [x(0), x(1), x(2), x(3)] and the second sub-excitation signal s2(t). The phase sequence corresponding to the second sub-excitation signal s2(t) is [1, -1, 1, -1].

[0212] For other details, please refer to step 102 and will not be described in detail here.

[0213] Step 203: The tag device sends an uplink reflected signal.

[0214] For specific details, please refer to step 103, which will not be repeated here.

[0215] Step 204: The network device receives an uplink signal, where the uplink signal is an uplink reflected signal sent by the tag device and is transmitted through a channel.

[0216] For specific details, please refer to step 104, which will not be repeated here.

[0217] Step 205: The network device performs diversity reception on the uplink signal in response to the received uplink signal.

[0218] Exemplarily, in this embodiment, the network device may obtain a first frequency domain sequence corresponding to the first uplink sub-reflected signal x1(t) and a second frequency domain sequence corresponding to the second uplink sub-reflected signal x2(t) based on formulas (9) and (10). The first frequency domain sequence is as follows: Fig.19a As shown, the second frequency domain sequence is Fig.19b As shown, that is, the second frequency domain sequence is cyclically shifted by N / 2 relative to the first frequency domain sequence.

[0219] Specifically, refer to Fig.19a and Fig.19b , the modulation symbol x(0) is on subcarrier 1 in the first frequency domain sequence, and the corresponding channel response is h f (1), the modulation symbol x(0) is on subcarrier 3 in the second frequency domain sequence, and the corresponding channel response is hf (3); The modulation symbol x(1) is on subcarrier 2 in the first frequency domain sequence, and the corresponding channel response is h f (2), the modulation symbol x(1) is on subcarrier 4 in the second frequency domain sequence, and the corresponding channel response is h f (4); The modulation symbol x(2) is on subcarrier 3 in the first frequency domain sequence, and the corresponding channel response is h f (3), the modulation symbol x(2) is on subcarrier 1 in the second frequency domain sequence, and the corresponding channel response is h f (1); The modulation symbol x(3) is on subcarrier 4 in the first frequency domain sequence, and the corresponding channel response is h f (4), the modulation symbol x(3) is on subcarrier 2 in the second frequency domain sequence, and the corresponding channel response is h f (2).

[0220] Next, the network device combines the frequency domain components of each modulation symbol to obtain the frequency domain components corresponding to each modulation symbol.

[0221] Exemplarily, the frequency domain component corresponding to the modulation symbol x(0) is: f (1)+h f (3))*x(0); the frequency domain component corresponding to the modulation symbol x(1) is: (h f (2)+h f (4))*x(1); the frequency domain component corresponding to the modulation symbol x(2) is: (h f (3)+h f (1))*x(2); the frequency domain component corresponding to the modulation symbol x(3) is: (h f (4)+h f (2))*x(3).

[0222] Scene 3

[0223] In this scenario, a detailed description is given by taking the second uplink sub-reflected signal implementing N / 4 cyclic left shift in the frequency domain as an example.

[0224] Combination Figure 1a The communication system shown in Fig. 20 FIG. 1 is a flow chart of a backscatter communication method in an embodiment of the present application. Fig. 20 middle:

[0225] Step 301: The network device sends an excitation signal to the tag device, wherein the excitation signal includes a first sub-excitation signal and a second sub-excitation signal, the second excitation signal is obtained by multiplying the first excitation signal by a phase shift signal, and the phase sequence corresponding to the phase shift signal is [1, j, -1, -j].

[0226] Specifically, in this embodiment, based on formula (3) and formula (4), when n=4k in the second sub-excitation signal s2(t), φ n =0; when n=4k+1, When n=4k+2, φ n =π; when n = 4k + 3, Substituting into formula (4), the phase sequence corresponding to the second sub-excitation signal s2(t) is [1, j, -1, -j]. That is, it can be understood that the second sub-excitation signal s2(t) is the first sub-excitation signal s1(t) multiplied by the phase shift signal with a phase sequence of [1, j, -1, -j]. The schematic diagram of the second sub-excitation signal s2(t) can be referred to Fig.10 .

[0227] Step 302: The tag device generates an uplink reflection signal in response to the received excitation signal sent by the network device, wherein the uplink reflection signal includes a first sub-uplink reflection signal and a second sub-uplink reflection signal, the first sub-uplink reflection signal is obtained by multiplying the tag information by the first sub-excitation signal, and the second sub-uplink reflection signal is obtained by multiplying the tag information by the second sub-excitation signal.

[0228] For example, in this embodiment, the tag device transmits tag information twice, that is, repeatedly transmits tag information once, and the generated uplink reflection signal x(t) can still refer to Fig.17 shown.

[0229] Combination Fig.17 ,like Fig.21a The figure shows a schematic diagram of the generation of the first sub-uplink reflected signal x1(t). Specifically, assuming that the label information x(n) is [x(0), x(1), x(2), x(3)], the first sub-uplink reflected signal x1(t) is the product of the label information [x(0), x(1), x(2), x(3)] and the first sub-excitation signal s1(t), wherein the phase sequence corresponding to the first sub-excitation signal s1(t) is [1, 1, 1, 1].

[0230] like Figure 21b The figure shows a schematic diagram of the generation of the second sub-uplink reflected signal x2(t). The tag information repeatedly sent by the tag device still contains the modulation symbols [x(0), x(1), x(2), x(3)]. The second sub-uplink reflected signal x2(t) is the product of the tag information [x(0), x(1), x(2), x(3)] and the second sub-excitation signal s2(t). The phase sequence corresponding to the second sub-excitation signal s2(t) is [1, j, -1, -j].

[0231] For other details, please refer to step 102 and will not be described in detail here.

[0232] Step 303: The tag device sends an uplink reflection signal.

[0233] For specific details, please refer to step 103, which will not be repeated here.

[0234] Step 304: The network device receives an uplink signal, where the uplink signal is an uplink reflected signal sent by the tag device and is transmitted through a channel.

[0235] For specific details, please refer to step 104, which will not be repeated here.

[0236] Step 305: The network device performs diversity reception on the uplink signal in response to the received uplink signal.

[0237] Exemplarily, in this embodiment, the network device may obtain a first frequency domain sequence corresponding to the first uplink sub-reflected signal x1(t) and a second frequency domain sequence corresponding to the second uplink sub-reflected signal x2(t) based on formulas (9) and (10). The first frequency domain sequence is as follows: Fig.22a As shown, the second frequency domain sequence is Figure 22b As shown, that is, the second frequency domain sequence is cyclically left-shifted by N / 4 relative to the first frequency domain sequence. Optionally, it can also be understood that the second frequency domain sequence is cyclically right-shifted by 3N / 4 relative to the first frequency domain sequence.

[0238] Specifically, refer to Fig.22a and Figure 22b , the modulation symbol x(0) is on subcarrier 1 in the first frequency domain sequence, and the corresponding channel response is h f (1), the modulation symbol x(0) is on subcarrier 4 in the second frequency domain sequence, and the corresponding channel response is h f (4); The modulation symbol x(1) is on subcarrier 2 in the first frequency domain sequence, and the corresponding channel response is h f (2), the modulation symbol x(1) is on subcarrier 1 in the second frequency domain sequence, and the corresponding channel response is h f (1); The modulation symbol x(2) is on subcarrier 3 in the first frequency domain sequence, and the corresponding channel response is h f (3), the modulation symbol x(2) is on subcarrier 2 in the second frequency domain sequence, and the corresponding channel response is h f (2); The modulation symbol x(3) is on subcarrier 4 in the first frequency domain sequence, and the corresponding channel response is h f (4), the modulation symbol x(3) is on subcarrier 3 in the second frequency domain sequence, and the corresponding channel response is h f (3).

[0239] Next, the network device combines the frequency domain components of each modulation symbol to obtain the frequency domain components corresponding to each modulation symbol.

[0240] Exemplarily, the frequency domain component corresponding to the modulation symbol x(0) is: f (1)+h f (4))*x(0); the frequency domain component corresponding to the modulation symbol x(1) is: (h f (2)+h f (1))*x(1); the frequency domain component corresponding to the modulation symbol x(2) is: (h f (3)+h f (2))*x(2); the frequency domain component corresponding to the modulation symbol x(3) is: (h f (4)+h f (3))*x(3).

[0241] Scene 4

[0242] In this scenario, a detailed description is given by taking the second uplink sub-reflected signal implementing a 3N / 4 cyclic shift in the frequency domain as an example.

[0243] Combination Figure 1a The communication system shown in Fig.23 FIG. 1 is a flow chart of a backscatter communication method in an embodiment of the present application. Fig.23 middle:

[0244] Step 401: The network device sends an excitation signal to the tag device, wherein the excitation signal includes a first sub-excitation signal and a second sub-excitation signal, the second excitation signal is obtained by multiplying the first excitation signal by a phase shift signal, and the phase sequence corresponding to the phase shift signal is [1, -j, -1, j].

[0245] Specifically, in this embodiment, based on formula (3) and formula (4), when n=4k in the second sub-excitation signal s2(t), φ n =0; when n=4k+1, When n=4k+2, φ n =π; when n = 4k + 3, Substituting into formula (4), the phase sequence corresponding to the second sub-excitation signal s2(t) is [1, j, -1, -j]. That is, it can be understood that the second sub-excitation signal s2(t) is the first sub-excitation signal s1(t) multiplied by the phase shift signal with a phase sequence of [1, j, -1, -j]. The schematic diagram of the second sub-excitation signal s2(t) can be referred to Fig.10 . Exemplarily, in this embodiment, the time length occupied by the first sub-excitation signal s1(t) and the second sub-excitation signal s2(t) is 4T, the phase sequence corresponding to the first sub-excitation signal s1(t) is [1, 1, 1, 1], and the phase sequence corresponding to the second sub-excitation signal s2(t) is [1, j, -1, -j].

[0246] For other details, please refer to step 101 and will not be described in detail here.

[0247] Step 402: The tag device generates an uplink reflection signal in response to the received excitation signal sent by the network device, wherein the uplink reflection signal includes a first sub-uplink reflection signal and a second sub-uplink reflection signal, the first sub-uplink reflection signal is obtained by multiplying the tag information by the first sub-excitation signal, and the second sub-uplink reflection signal is obtained by multiplying the tag information by the second sub-excitation signal.

[0248] For example, in this embodiment, the tag device transmits tag information twice, which can also be understood as repeating the transmission of tag information once. The generated uplink reflection signal can still refer to Fig.17 shown.

[0249] Combination Fig.17 ,like Fig.24a The figure shows a schematic diagram of the generation of the first sub-uplink reflected signal x1(t). Specifically, assuming that the label information x(n) is [x(0), x(1), x(2), x(3)], the first sub-uplink reflected signal x1(t) is the product of the label information [x(0), x(1), x(2), x(3)] and the first sub-excitation signal s1(t), wherein the phase sequence corresponding to the first sub-excitation signal s1(t) is [1, 1, 1, 1].

[0250] like Figure 24b The figure shows a schematic diagram of the generation of the second sub-uplink reflected signal x2(t). The tag information repeatedly sent by the tag device still contains the modulation symbols [x(0), x(1), x(2), x(3)]. The second sub-uplink reflected signal x2(t) is the product of the tag information [x(0), x(1), x(2), x(3)] multiplied by the second sub-excitation signal s2(t). The phase sequence corresponding to the second sub-excitation signal s2(t) is [1, j, -1, -j].

[0251] For other details, please refer to step 102 and will not be described in detail here.

[0252] Step 403: The tag device sends an uplink reflection signal.

[0253] For specific details, please refer to step 103, which will not be repeated here.

[0254] Step 404: The network device receives an uplink signal, where the uplink signal is an uplink reflected signal sent by the tag device and is transmitted through a channel.

[0255] For specific details, please refer to step 104, which will not be repeated here.

[0256] Step 405: The network device performs diversity reception on the uplink signal in response to the received uplink signal.

[0257] Exemplarily, in this embodiment, the network device may obtain a first frequency domain sequence corresponding to the first uplink sub-reflected signal x1(t) and a second frequency domain sequence corresponding to the second uplink sub-reflected signal x2(t) based on formulas (9) and (10). The first frequency domain sequence is as follows: Fig.25a As shown, the second frequency domain sequence is Fig.25b As shown, that is, the second frequency domain sequence is cyclically left-shifted by N3 / 4 relative to the first frequency domain sequence. Optionally, it can also be understood that the second frequency domain sequence is cyclically right-shifted by N / 4 relative to the first frequency domain sequence.

[0258] Specifically, refer to Fig.19a and Fig.19b , the modulation symbol x(0) is on subcarrier 1 in the first frequency domain sequence, and the corresponding channel response is h f (t), the modulation symbol x(0) is on subcarrier 2 in the second frequency domain sequence, and the corresponding channel response is h f (2); The modulation symbol x(1) is on subcarrier 2 in the first frequency domain sequence, and the corresponding channel response is h f (2), the modulation symbol x(1) is on subcarrier 3 in the second frequency domain sequence, and the corresponding channel response is h f (3); The modulation symbol x(2) is on subcarrier 3 in the first frequency domain sequence, and the corresponding channel response is h f (3), the modulation symbol x(2) is on subcarrier 4 in the second frequency domain sequence, and the corresponding channel response is h f (4); The modulation symbol x(3) is on subcarrier 4 in the first frequency domain sequence, and the corresponding channel response is h f (4), the modulation symbol x(3) is on subcarrier 1 in the second frequency domain sequence, and the corresponding channel response is h f (1).

[0259] Next, the network device combines the frequency domain components of each modulation symbol to obtain the frequency domain components corresponding to each modulation symbol.

[0260] Exemplarily, the frequency domain component corresponding to the modulation symbol x(0) is: f (1)+h f (2))*x(0); the frequency domain component corresponding to the modulation symbol x(1) is: (h f (2)+h f (3))*x(1); the frequency domain component corresponding to the modulation symbol x(2) is: (h f (3)+h f (4))*x(2); the frequency domain component corresponding to the modulation symbol x(3) is: (h f (4)+h f(1))*x(3).

[0261] In a possible implementation, if the repeated tag information is to be shifted N / 2 in the frequency domain, in addition to using the excitation signal with phase shift characteristics in scenario one to scenario two, the tag device can also adjust the load state of the antenna termination so that the polarity of the even-bit modulation symbol of the repeated tag information remains unchanged, while the polarity of the odd-bit modulation symbol is opposite. Specifically, in this embodiment, the tag information transmitted for the first time is the same as that in scenario one to scenario two, and will not be repeated here. For the repeatedly transmitted tag information, it can be expressed as:

[0262]

[0263] Wherein, Π represents the adjusted reflection coefficient of the tag device. Specifically, as described above, the tag device can realize the "absorption" state or "reflection" state of the tag device based on Γ(z). In this embodiment, Π(z) is the opposite state to Γ(z). That is to say, for the odd-bit modulation symbol in the tag information, that is, the modulation symbol corresponding to x2(2*m+1) in formula (12), when adjusting the state of the tag device, the tag device adopts the adjustment coefficient Π(z) opposite to the original Γ(z), thereby achieving the same effect as in scenario 2.

[0264] In a possible implementation, the technical solution of the present application can also be applied to the scenario of repeatedly sending label information multiple times. Optionally, when the label information is repeatedly sent twice or more, it can be combined with any cyclic shift method in scenario 2 to scenario 4, that is, the signal part corresponding to the repeatedly sent label information can implement at least one of N / 2, N / 4, 3N / 4 cyclic shifts, which is not limited by the present application. For example, Fig.26 As shown, taking the case of sending the tag information twice and three times as an example, specifically, when the tag device sends the tag information twice, that is, sends the same tag information three times in total (also called 3x repetition coding), the signal corresponding to the tag information sent the second time can achieve N / 4 cyclic left shift in the frequency domain, and the signal corresponding to the tag information sent the third time can achieve N / 2 cyclic left shift in the frequency domain. When the tag device sends the tag information three times, that is, sends the same tag information four times in total (also called 4x repetition coding), the signal corresponding to the tag information sent the second time can achieve N / 4 cyclic left shift in the frequency domain, the signal corresponding to the tag information sent the third time can achieve N / 2 cyclic shift in the frequency domain, and the signal corresponding to the tag information sent the fourth time can achieve 3N / 4 cyclic left shift in the frequency domain.

[0265] In this application, only two points are used, namely Figure 1aThe scenario including the network device and the tag device shown in FIG is used for illustration. In other embodiments, the present application can also be applied to a three-point scenario, that is, Figure 1b The application scenarios in the embodiment include the scenarios of the network device 100, the relay device 300, and the tag device 200. The network device 100 sends an indication message to the relay device 300 to instruct the tag device 200 to send an uplink reflection signal, and the relay device 300 sends the indication message to the tag device 200. Subsequently, the relay device 300 sends an excitation signal with a phase shift characteristic to the tag device 200, and the tag device 200 can repeatedly send tag information to the network device 100 based on the excitation signal. In other words, in the three-point scenario, except that the node sending the excitation signal is different from that in scenarios one to four, other details are the same as those in scenarios one to four, and will not be repeated here.

[0266] The above mainly introduces the solution provided by the embodiment of the present application from the perspective of the interaction between various network elements. It can be understood that in order to realize the above functions, the network equipment and the label equipment include hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should easily realize that, in combination with the units and algorithm steps of each example described in the embodiments disclosed in this document, the embodiments of the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of this application.

[0267] The embodiment of the present application can divide the network device and the tag device into functional modules according to the above method example. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present application is schematic and is only a logical functional division. There may be other division methods in actual implementation.

[0268] In the case where each functional module is divided into each functional module according to each function, Fig. 27 A possible structural diagram of the network device 500 involved in the above embodiment is shown. Fig. 27 As shown, the network device 500 may include: a transceiver module 501 and a processing module 502 .

[0269] In one example, the network device 500 may be used to implement the above-mentioned embodiment. Figure 8The method shown, specifically, the transceiver module 501 is used to perform the step of "sending an excitation signal to a tag device", wherein the excitation signal includes a first sub-excitation signal and a second sub-excitation signal, the second sub-excitation signal and the first sub-excitation signal occupy the same time, and the phase of some symbols in the second sub-excitation signal is different from that of some symbols in the first sub-excitation signal, for example, the transceiver module 501 can be used to support the network device to perform step 101 in the above method embodiment. The transceiver module 501 is also used to perform the step of "receiving an uplink signal", wherein the uplink signal is an uplink reflection signal sent by the tag device after being transmitted through a channel, the uplink reflection signal includes a first sub-uplink reflection signal and a second sub-uplink reflection signal, the first sub-uplink reflection signal is obtained by multiplying the tag information by the first sub-excitation signal, and the second sub-uplink reflection signal is obtained by multiplying the tag information by the second sub-excitation signal, for example, the transceiver module 501 can be used to support the network device to perform step 104 in the above method embodiment. The processing module 502 is used to execute the step of "performing diversity reception on the uplink signal in response to the received uplink signal". For example, the processing module 502 can be used to support the network device to execute step 105 in the above method embodiment.

[0270] In another example, the network device 500 may be used to implement the above-mentioned embodiment. Fig.16 In the method shown, specifically, the transceiver module 501 is used to execute the step of "sending an excitation signal to the tag device", wherein the excitation signal includes a first sub-excitation signal and a second sub-excitation signal, the second excitation signal is obtained by multiplying the first excitation signal by the phase-shifted signal, and the phase sequence corresponding to the phase-shifted signal is [1, -1, 1, -1]. For example, the transceiver module 501 can be used to support the network device to execute step 201 in the above method embodiment. The transceiver module 501 is also used to execute the step of "receiving an uplink signal". For example, the transceiver module 501 can be used to support the network device to execute step 204 in the above method embodiment. The processing module 502 is used to execute the step of "performing diversity reception on the uplink signal in response to the received uplink signal". For example, the processing module 502 can be used to support the network device to execute step 205 in the above method embodiment.

[0271] In another example, the network device 500 may be used to implement the above-mentioned embodiment. Fig. 20In the method shown, specifically, the transceiver module 501 is used to execute the step of "sending an excitation signal to the tag device", wherein the excitation signal includes a first sub-excitation signal and a second sub-excitation signal, the second excitation signal is obtained by multiplying the first excitation signal by the phase-shifted signal, and the phase sequence corresponding to the phase-shifted signal is [1, j, -1, -j]. For example, the transceiver module 501 can be used to support the network device to execute step 301 in the above method embodiment. The transceiver module 501 is also used to execute the step of "receiving an uplink signal". For example, the transceiver module 501 can be used to support the network device to execute step 304 in the above method embodiment. The processing module 502 is used to execute the step of "performing diversity reception on the uplink signal in response to the received uplink signal". For example, the processing module 502 can be used to support the network device to execute step 305 in the above method embodiment.

[0272] In another example, the network device 500 may be used to implement the above-mentioned embodiment. Fig.23 The method shown, specifically, the transceiver module 501 is used to execute the step of "sending an excitation signal to the tag device", wherein the excitation signal includes a first sub-excitation signal and a second sub-excitation signal, the second excitation signal is obtained by multiplying the first excitation signal by the phase-shifted signal, and the phase sequence corresponding to the phase-shifted signal is [1, -j, -1, j]. For example, the transceiver module 501 can be used to support the network device to execute step 501 in the above method embodiment. The transceiver module 501 is also used to execute the step of "receiving an uplink signal". For example, the transceiver module 501 can be used to support the network device to execute step 404 in the above method embodiment. The processing module 502 is used to execute the step of "performing diversity reception on the uplink signal in response to the received uplink signal". For example, the processing module 502 can be used to support the network device to execute step 405 in the above method embodiment.

[0273] Fig.28 A possible structural diagram of the label device 600 involved in the above embodiment is shown. Fig.28As shown, the tag device 600 may include: a transceiver module 601, the transceiver module 601 is used to perform the step of "receiving an excitation signal sent by a network device", wherein the excitation signal includes a first sub-excitation signal and a second sub-excitation signal, the second sub-excitation signal occupies the same time as the first sub-excitation signal, and some symbols in the second sub-excitation signal have different phases from some symbols in the first sub-excitation signal. For example, the transceiver module 601 can be used to support the network device to perform the action of receiving the excitation signal in step 102, step 202, step 302, and step 402 in the above method embodiments. Optionally, the tag device 600 further includes a processing module 602, which is used to execute "generating an uplink reflection signal in response to the received excitation signal", wherein the uplink reflection signal includes a first sub-uplink reflection signal and a second sub-uplink reflection signal, the first sub-uplink reflection signal is obtained by multiplying the tag information by the first sub-excitation signal, and the second sub-uplink reflection signal is obtained by multiplying the tag information by the second sub-excitation signal. For example, the processing module 602 can be used to support the network device to execute step 102, step 202, step 302, and step 402 in the above method embodiment. The transceiver module 601 is also used to execute the step of "sending an uplink reflection signal to the network device". For example, the transceiver module 601 can be used to support the network device to execute step 103, step 203, step 303, and step 403 in the above method embodiment.

[0274] The following describes a device provided by an embodiment of the present application. Fig.29 As shown:

[0275] The device includes a processing module 701 and a communication module 702. Optionally, the device also includes a storage module 703. The processing module 701, the communication module 702 and the storage module 703 are connected via a communication bus.

[0276] The communication module 702 may be a device with transceiver functions, and is used to communicate with other network devices or communication networks.

[0277] The storage module 703 may include one or more memories, and the memory may be a device in one or more devices or circuits for storing programs or data.

[0278] The storage module 703 may exist independently and be connected to the processing module 701 via a communication bus. The storage module may also be integrated with the processing module 701.

[0279] The apparatus 700 may be used in a network device, a circuit, a hardware component, or a chip.

[0280] The apparatus 700 may be a network device in an embodiment of the present application. The schematic diagram of the network device may be as follows: Figure 2Optionally, the communication module 702 of the apparatus 700 may include an antenna and a transceiver of a network device, for example Figure 2 The communication module 702 may also include a network interface of a network device, such as Figure 2 The network interface 304 in.

[0281] The device 700 may be a chip in the network device in the embodiment of the present application. The communication module 702 may be an input or output interface, a pin or a circuit, etc. Optionally, the storage module may store computer execution instructions of the method on the network device side so that the processing module 701 executes the method on the network device side in the above embodiment. The storage module 703 may be a register, a cache or a RAM, etc. The storage module 703 may be integrated with the processing module 701; the storage module 703 may be a ROM or other type of static storage device that can store static information and instructions, and the storage module 703 may be independent of the processing module 701. Optionally, with the development of wireless communication technology, the transceiver may be integrated into the device 700, for example, the communication module 702 integrates the transceiver 303 and the network interface 304.

[0282] When the apparatus 700 is a network device or a chip in a network device in an embodiment of the present application, the method executed by the network device in the above embodiment can be implemented.

[0283] The apparatus 700 may be a label device in an embodiment of the present application. Figure 6 Optionally, the communication module 702 of the apparatus 700 may include an antenna of a tag device.

[0284] The device 700 may be a chip in the tag device in the embodiment of the present application. The communication module 702 may be an input or output interface, a pin or a circuit, etc. Optionally, the storage module may store computer execution instructions of the method on the tag device side so that the processing module 701 executes the method on the tag device side in the above embodiment. The storage module 703 may be a register, a cache or a RAM, etc., and the storage module 703 may be integrated with the processing module 701; the storage module 703 may be a ROM or other types of static storage devices that can store static information and instructions, and the storage module 703 may be independent of the processing module 701.

[0285] When the apparatus 700 is a tag device or a chip in a tag device in an embodiment of the present application, the apparatus 700 can implement the method executed by the tag device in the above embodiment.

[0286] For the case where the communication device is implemented in the form of a chip or a chip system, see Fig.30 Schematic diagram of the chip structure shown. Fig.30The chip shown includes a processor 801 and an interface 802 . The number of the processor 801 may be one or more, and the number of the interface 802 may be multiple. Optionally, the chip or chip system may include a memory 803 .

[0287] The present application embodiment also provides a computer-readable storage medium. The method described in the above embodiment can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. If implemented in software, the function can be stored as one or more instructions or codes on a computer-readable medium or transmitted on a computer-readable medium. Computer-readable media may include computer storage media and communication media, and may also include any medium that can transfer a computer program from one place to another. The storage medium may be any available medium that can be accessed by a computer.

[0288] As an optional design, the computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage devices, or any other medium that can be used to carry or store the required program code in the form of instructions or data structures, and can be accessed by the computer. Moreover, any connection is appropriately referred to as a computer-readable medium. For example, if the software is transmitted from a website, server or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) or wireless technology (such as infrared, radio and microwave), the coaxial cable, fiber optic cable, twisted pair, DSL or wireless technologies such as infrared, radio and microwave are included in the definition of the medium. Disks and optical disks as used herein include compact disks (CDs), laser disks, optical disks, digital versatile disks (DVDs), floppy disks and blue-ray disks, where disks usually reproduce data magnetically, while optical disks reproduce data optically using lasers. The combination of the above should also be included in the scope of computer-readable media.

[0289] The embodiments of the present application also provide a computer program product. The methods described in the above embodiments can be implemented in whole or in part by software, hardware, firmware or any combination thereof. If implemented in software, they can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the above computer program instructions are loaded and executed on a computer, the process or function described in the above method embodiment is generated in whole or in part. The above computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device or other programmable device.

[0290] An embodiment of the present application also provides a communication system, which may include the network device and the tag device in the above embodiment.

[0291] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A network device, characterized in that: The device comprises a processor, a memory and a transceiver, wherein the processor, the memory and the transceiver are coupled, the memory is used to store program instructions, and the program instructions are configured to be executed by the processor; The transceiver is used to send an excitation signal to the tag device, wherein the excitation signal includes a first sub-excitation signal and a second sub-excitation signal, the second sub-excitation signal occupies the same time as the first sub-excitation signal, and the phase of some symbols in the second sub-excitation signal is different from that of some symbols in the first sub-excitation signal; The transceiver is further used to receive an uplink signal, where the uplink signal is obtained after the uplink reflection signal sent by the tag device is transmitted through a channel, wherein the uplink reflection signal includes a first sub-uplink reflection signal and a second sub-uplink reflection signal, the first sub-uplink reflection signal is obtained by multiplying the tag information by the first sub-excitation signal, and the second sub-uplink reflection signal is obtained by multiplying the tag information by the second sub-excitation signal; The processor is configured to perform diversity reception on the uplink signal in response to the received uplink signal.

2. The device according to claim 1, characterized in that in, The first sub-excitation signal s1(t) is: s1(t)=cos(2πf(t-nT)+φ0) The second sub-excitation signal s2(t) is: s2(t)=cos(2πf(t-nT)+φ0+φ n ) Wherein, T is the time length occupied by the symbol in the tag information, N is the number of symbols in the tag information, n=0...N-1, t=(n-1)T...nT, f is the carrier frequency, φ0 is the initial phase, φ n is the phase of the nth symbol of the second sub-excitation signal s2(t).

3. The device according to claim 2, characterized in that in, When n is an even number, φ n =0, when n is an odd number, φ n =π; or, When n is an even number, φ n =π, when n is an odd number, φ n =0.

4. The device according to claim 2, characterized in that in, When n=4p, φ n =0; n = 4p + 1, When n=4p+2, φ n =π; when n = 4p + 3, in, 5. The device according to claim 2, characterized in that in, When n=4p, φ n =0, n=4p+1, When n=4p+2, φ n =π; when n = 4p + 3, in, 6. The device according to any one of claims 1 to 5, characterized in that The processor is specifically used for: Performing a frequency domain transform on the uplink signal to obtain an uplink frequency domain sequence, wherein the uplink frequency domain sequence includes a first frequency domain sequence and a second frequency domain sequence, the first frequency domain sequence is a frequency domain sequence corresponding to the first sub-uplink reflected signal, and the second frequency domain sequence is a frequency domain sequence corresponding to the second sub-uplink reflected signal, wherein the second frequency domain sequence is a cyclic shift sequence of the first frequency domain sequence; Acquire a first frequency domain component of the symbol in the tag information on the first frequency domain sequence, and a second frequency domain component of the symbol in the tag information on the second frequency domain sequence; The frequency domain component of the symbol in the label information is obtained according to the first frequency domain component and the second frequency domain component.

7. The device according to claim 6, characterized in that The first frequency domain sequence for: Among them, h f (k) is the channel response on the kth subcarrier, The frequency domain sequence is obtained by performing frequency domain transformation on the first sub uplink reflected signal.

8. The device according to claim 7, characterized in that The second uplink reflected signal for: Among them, h f (k) is the channel response on the kth subcarrier, is the second uplink reflected signal x(n) The frequency domain sequence obtained by frequency domain transformation is: is the phase sequence corresponding to the second sub-excitation signal, x(n) is the label information, represents the frequency domain sequence corresponding to the first sub-uplink reflected signal An integer remainder is taken, where N is the number of symbols included in the tag information x(n), k=0, K, N-1, and ΔN is an integer greater than 0 and less than or equal to N-1.

9. The device according to any one of claims 1 to 5, 7 and 8, characterized in that: The transceiver is further used to send an indication signal to the tag device before sending the excitation signal, wherein the indication signal is used to instruct the tag device to send the uplink reflection signal.

10. A labeling device, characterized in that: The invention comprises a transceiver, which is used to receive an excitation signal sent by a network device, wherein the excitation signal comprises a first sub-excitation signal and a second sub-excitation signal, wherein the second sub-excitation signal occupies the same time as the first sub-excitation signal, and the phases of some symbols in the second sub-excitation signal are different from those of some symbols in the first sub-excitation signal; The transceiver is used to send an uplink reflection signal in response to the received excitation signal; wherein the uplink reflection signal includes a first sub-uplink reflection signal and a second sub-uplink reflection signal, the first sub-uplink reflection signal is obtained by multiplying the label information by the first sub-excitation signal, and the second sub-uplink reflection signal is obtained by multiplying the label information by the second sub-excitation signal.

11. The device according to claim 10, characterized in that in, The first sub-excitation signal s1(t) is: s1(t)=cos(2πf(t-nT)+φ0) The second sub-excitation signal s2(t) is: s2(t)=cos(2πf(t-nT)+φ0+φ n ) Wherein, T is the time length occupied by the symbol in the tag information, N is the number of symbols in the tag information, n=0...N-1, t=(n-1)T...nT, f is the carrier frequency, φ0 is the initial phase, φ n is the phase of the nth symbol of the second sub-excitation signal s2(t).

12. The device according to claim 11, characterized in that in, When n in the second sub-excitation signal s2(t) is an even number, φ n =0, when n is an odd number, φ n =π; or, When n in the second sub-excitation signal s2(t) is an even number, φ n =π, when n is an odd number, φ n =0.

13. The device according to claim 11, characterized in that in, When n=4k in the second sub-excitation signal s2(t), φ n =0; when n=4k+1, When n=4k+2, φ n =π; when n = 4k + 3, in, 14. The device according to claim 11, characterized in that in, When n=4k in the second sub-excitation signal, φ n =0, n=4k+1, When n=4k+2, φ n =π; when n = 4k + 3, in, 15. The device according to any one of claims 10 to 14, characterized in that The tag device also includes an antenna, a first load, a second load and a processor, wherein the processor is used to terminate the antenna to the first load or the second load in response to the received excitation signal based on the symbol in the tag information, wherein the antenna is terminated to the first load so that the tag device is in an absorbing state, and the antenna is terminated to the second load so that the tag device is in a reflecting state.

16. The device according to any one of claims 10 to 14, characterized in that The transceiver is further used to receive an indication signal sent by the network device, where the indication signal is used to instruct the tag device to send the uplink reflected signal.

17. A backscatter communication method, characterized in that: include: The network device sends an excitation signal to the tag device, the excitation signal comprising a first sub-excitation signal and a second sub-excitation signal, the second sub-excitation signal occupies the same time as the first sub-excitation signal, and the phase of some symbols in the second sub-excitation signal is different from that of some symbols in the first sub-excitation signal; The network device receives an uplink signal, where the uplink signal is obtained after the uplink reflection signal sent by the tag device is transmitted through a channel, wherein the uplink reflection signal includes a first sub-uplink reflection signal and a second sub-uplink reflection signal, the first sub-uplink reflection signal is obtained by multiplying the tag information by the first sub-excitation signal, and the second sub-uplink reflection signal is obtained by multiplying the tag information by the second sub-excitation signal; The network device performs diversity reception on the uplink signal in response to the received uplink signal.

18. The method according to claim 17, characterized in that in, The first sub-excitation signal s1(t) is: s1(t)=cos(2πf(t-nT)+φ0) The second sub-excitation signal s2(t) is: s2(t)=cos(2πf(t-nT)+φ0+φ n ) Wherein, T is the time length occupied by the symbol in the tag information, N is the number of symbols in the tag information, n=0...N-1, t=(n-1)T...nT, f is the carrier frequency, φ0 is the initial phase, φ n is the phase of the nth symbol of the second sub-excitation signal s2(t).

19. The method according to claim 18, characterized in that in, When n in the second sub-excitation signal s2(t) is an even number, φ n =0, when n is an odd number, φ n =π; or, When n in the second sub-excitation signal s2(t) is an even number, φ n =π, when n is an odd number, φ n =0.

20. The method according to claim 18, characterized in that in, When n=4p in the second sub-excitation signal s2(t), φ n =0; n = 4p + 1, When n=4p+2, φ n =π; when n = 4p + 3, in, 21. The method according to claim 18, characterized in that in, When n=4p in the second sub-excitation signal, φ n =0, n=4p+1, When n=4p+2, φ n =π; when n = 4p + 3, in, 22. The method according to any one of claims 17 to 21, characterized in that The network device performs diversity reception on the uplink signal, including: Performing a frequency domain transform on the uplink signal to obtain an uplink frequency domain sequence, wherein the uplink frequency domain sequence includes a first frequency domain sequence and a second frequency domain sequence, the first frequency domain sequence is a frequency domain sequence corresponding to the first sub-uplink reflected signal, and the second frequency domain sequence is a frequency domain sequence corresponding to the second sub-uplink reflected signal, wherein the second frequency domain sequence is a cyclic shift sequence of the first frequency domain sequence; Acquire a first frequency domain component of the symbol in the tag information on the first frequency domain sequence, and a second frequency domain component of the symbol in the tag information on the second frequency domain sequence; The frequency domain component of the symbol in the label information is obtained according to the first frequency domain component and the second frequency domain component.

23. The method according to claim 22, characterized in that The first frequency domain sequence for: Among them, h f (k) is the channel response on the kth subcarrier, The frequency domain sequence is obtained by performing frequency domain transformation on the first sub uplink reflected signal.

24. The method according to claim 23, characterized in that The second uplink reflected signal for: Among them, h f (k) is the channel response on the kth subcarrier, is the second uplink reflected signal x(n) The frequency domain sequence obtained by frequency domain transformation is: is the phase sequence corresponding to the second sub-excitation signal, x(n) is the label information, represents the frequency domain sequence corresponding to the first sub-uplink reflected signal An integer remainder is taken, where N is the number of symbols included in the tag information x(n), k=0, K, N-1, and ΔN is an integer greater than 0 and less than or equal to N-1.

25. The method according to any one of claims 17 to 21, 23 and 24, characterized in that: Before sending the excitation signal, the network device further includes: An instruction signal is sent to the tag device, where the instruction signal is used to instruct the tag device to send the uplink reflected signal.

26. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and the computer program is executed by a network device to control the network device to execute the method according to any one of claims 17 to 25.

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