CN117639909A

CN117639909A - Backscatter communication processing method, apparatus, communication device, and readable storage medium

Info

Publication number: CN117639909A
Application number: CN202210988857.3A
Authority: CN
Inventors: 姜大洁; 吴建明
Original assignee: Vivo Mobile Communication Co Ltd
Current assignee: Vivo Mobile Communication Co Ltd
Priority date: 2022-08-17
Filing date: 2022-08-17
Publication date: 2024-03-01
Also published as: WO2024037447A1

Abstract

The application discloses a signal transmission method, a signal transmission device, a communication device and a readable storage medium, wherein the signal transmission method comprises the following steps: the first device transmits first information related to the backscatter communication, the first information being indicative of any one of: the transmission waveform of the main signal is a single carrier signal waveform, and the transmission waveform of the auxiliary signal is a single carrier signal waveform; the transmission waveform of the main signal is a single carrier signal waveform, and the transmission waveform of the auxiliary signal is a multi-carrier signal waveform; the transmission waveform of the main signal is a multi-carrier signal waveform, and the transmission waveform of the auxiliary signal is a single-carrier signal waveform; the transmission waveform of the main signal is a multi-carrier signal waveform, and the transmission waveform of the auxiliary signal is a multi-carrier signal waveform.

Description

Backscatter communication processing method, apparatus, communication device, and readable storage medium

Technical Field

The application belongs to the technical field of communication, and particularly relates to a backscattering communication processing method, a backscattering communication processing device, communication equipment and a readable storage medium.

Background

Backscatter communication is where the tag uses radio frequency signals in other devices or environments to signal to transmit its own information. For example, the base station transmits a Primary Signal, and the terminal receives the Primary Signal and also receives a tag reflection Signal. The tag reflected Signal is modulated by a main Signal received by the tag and an auxiliary Signal (Secondary Signal) sent by the tag, however, the plurality of signals can increase complexity of Signal processing, so that it is difficult for the receiving end to effectively process the plurality of signals, and therefore how to effectively transmit the main Signal and the auxiliary Signal, so that the receiving end can simply and effectively demodulate the main Signal and the auxiliary Signal simultaneously is a problem to be solved.

Disclosure of Invention

The embodiment of the application provides a backscattering communication processing method, a backscattering communication processing device, a communication device and a readable storage medium, which solve the problem of how to effectively transmit a main signal and an auxiliary signal, so that a receiving end can simply and effectively demodulate the main signal and the auxiliary signal at the same time.

In a first aspect, a backscatter communication processing method is provided, including:

the first device transmits first information related to the backscatter communication, the first information being indicative of any one of:

the transmission waveform of the main signal is a single carrier signal waveform, and the transmission waveform of the auxiliary signal is a single carrier signal waveform;

the transmission waveform of the main signal is a single carrier signal waveform, and the transmission waveform of the auxiliary signal is a multi-carrier signal waveform;

the transmission waveform of the main signal is a multi-carrier signal waveform, and the transmission waveform of the auxiliary signal is a single-carrier signal waveform;

the transmission waveform of the main signal is a multi-carrier signal waveform, and the transmission waveform of the auxiliary signal is a multi-carrier signal waveform.

In a second aspect, there is provided a backscatter communication processing method, comprising:

the backscatter communication device receives first information relating to backscatter communication, the first information being indicative of any one of:

In a third aspect, there is provided a backscatter communication processing method, comprising:

the second device receives first information related to backscatter communications, the first information being indicative of at least one of:

In a fourth aspect, there is provided a backscatter communication processing apparatus for use with a first device, comprising:

A first transmitting module, configured to transmit first information related to backscatter communication, where the first information is used to indicate any one of:

In a fifth aspect, there is provided a backscatter communication processing apparatus for use with a backscatter communication device, comprising:

a first receiving module, configured to receive first information related to backscatter communication, where the first information is used to indicate any one of:

In a sixth aspect, there is provided a backscatter communication processing apparatus for use with a second device, comprising:

a third receiving module for receiving first information related to backscatter communications, the first information being indicative of at least one of:

In a seventh aspect, there is provided a communication device comprising: a processor, a memory and a program or instruction stored on the memory and executable on the processor, which program or instruction when executed by the processor implements the steps of the method according to the first or second or third aspect.

In an eighth aspect, there is provided a readable storage medium having stored thereon a program or instructions which when executed by a processor implement the steps of the method according to the first or second or third aspects.

In a ninth aspect, there is provided a chip comprising a processor and a communication interface, the communication interface and the processor being coupled, the processor being for running a program or instructions to implement the steps of the method according to the first or second or third aspects.

In a tenth aspect, there is provided a computer program/program product stored in a non-transitory storage medium, the program/program product being executed by at least one processor to implement the steps of the method according to the first or second or third aspect.

An eleventh aspect provides a communication system comprising a network side device for performing the steps of the method according to the first or third aspect, a terminal for performing the steps of the method according to the third or first aspect, and a backscatter communication device for performing the steps of the method according to the second aspect.

In the embodiment of the application, the transmission waveforms of the main signal and the auxiliary signal are configured through the first information, so that the mutual fusion and effective transmission of the main signal and the auxiliary signal are realized, the receiving end can simply and effectively demodulate the main signal and the auxiliary signal at the same time, and the transmission efficiency of symbiotic back scattering communication is improved.

Drawings

FIG. 1 is a schematic diagram of a backscatter communications transmitter;

FIGS. 2a, 2b and 2c are schematic diagrams of backscatter communications;

fig. 3 is a schematic diagram of a Passive IoT transmit and receive scenario;

fig. 4 is a schematic diagram of Passive IoT-related symbiotic backscatter primary and secondary signals;

fig. 5 is a schematic diagram of the gNB utilizing beamformed Passive IoT symbiotic backscattering;

FIG. 6 is a schematic diagram of a backscatter communications processing method provided in an embodiment of the present application;

FIG. 7 is a second schematic diagram of a backscatter communication processing method according to an embodiment of the present application;

FIG. 8 is a third schematic diagram of a backscatter communication processing method provided in an embodiment of the present application;

fig. 9a and 9b are schematic diagrams of modulation of a primary signal and a secondary signal in the time domain based on a single carrier;

fig. 10 is a schematic diagram of modulation of a primary signal and a secondary signal in the time domain based on a single carrier;

FIG. 11 is a schematic diagram of modulation of a primary signal and a secondary signal in the frequency domain based on an OFDM waveform;

fig. 12 is a schematic diagram of a single carrier correlated Tag received signal and a transmitted signal in the time and frequency domains;

fig. 13a, 13b, 13c are schematic diagrams of a gNB-Tag-UE multipath channel;

fig. 14a, 14b, 14c are schematic diagrams of single carrier correlated Tag received signals and transmitted signals in the time domain and the frequency domain;

fig. 15 is a schematic diagram of a multicarrier-related Tag received signal and a transmitted signal in the time domain and the frequency domain;

FIG. 16 is one of the schematic diagrams of the backscatter communications processing devices provided in an embodiment of the present application;

FIG. 17 is a second schematic diagram of a backscatter communications processing device provided in an embodiment of the present application;

FIG. 18 is a third schematic diagram of a backscatter communications processing device provided in an embodiment of the present application;

fig. 19 is a schematic diagram of a terminal provided in an embodiment of the present application;

fig. 20 is a schematic diagram of a network side device provided in an embodiment of the present application;

fig. 21 is a schematic diagram of a communication device provided in an embodiment of the present application.

Detailed Description

Technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application are within the scope of the protection of the present application.

The terms first, second and the like in the description and in the claims, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the application are capable of operation in sequences other than those illustrated or otherwise described herein, and that the terms "first" and "second" are generally intended to be used in a generic sense and not to limit the number of objects, for example, the first object may be one or more. Furthermore, in the description and claims, "and/or" means at least one of the connected objects, and the character "/" generally means a relationship in which the associated object is an "or" before and after.

It is noted that the techniques described in embodiments of the present application are not limited to long term evolution (Long Term Evolution, LTE)/LTE evolution (LTE-Advanced, LTE-a) systems, but may also be used in other wireless communication systems, such as code division multiple access (Code Division Multiple Access, CDMA), time division multiple access (Time Division Multiple Access, TDMA), frequency division multiple access (Frequency Division Multiple Access, FDMA), orthogonal frequency division multiple access (Orthogonal Frequency Division Multiple Access, OFDMA), single carrier frequency division multiple access (Single-carrier Frequency Division Multiple Access, SC-FDMA), and other systems. The terms "system" and "network" in embodiments of the present application are often used interchangeably, and the techniques described may be used for both the above-mentioned systems and radio technologies, as well as other systems and radio technologies. The following description describes a New air interface (NR) system for purposes of example and uses NR terminology in much of the description that follows, but these techniques are also applicable to applications other than NR system applications, such as generation 6 (6) ^th Generation, 6G) communication system.

In order to facilitate understanding of the embodiments of the present application, the following technical points are first described:

1. regarding backscatter communications (Backscatter Communication, BSC):

backscatter communication refers to the transmission of its own information by signal modulation of radio frequency signals in other devices or environments by a backscatter communication device. The modulation circuit is shown in fig. 1, and the backscattering communication device controls the reflection coefficient Γ of the circuit by adjusting the internal impedance of the backscattering communication device, so as to change the amplitude, frequency, phase and the like of an incident signal, thereby realizing the modulation of the signal. Wherein the reflection coefficient of the signal can be characterized as:

wherein Z is ₀ For the characteristic impedance of the antenna, Z ₁ Is the load impedance. Let the incident signal be S _in (t) the output signal isThus, by reasonably controlling the reflection coefficient, a corresponding amplitude modulation, frequency modulation or phase modulation can be achieved. Based on this, the Backscatter communication device may be a Backscatter in conventional radio frequency identification (Radio Frequency Identification, RFID) or a Passive or Semi-Passive internet of things (Passive/Semi-Passive Internet of Things) device.

Wherein the backscatter communication device may include:

(1) The backscatter communication device in conventional radio frequency identification (Radio Frequency Identification, RFID), typically a Tag, belongs to a Passive internet of things (Internet of Things, ioT) device (otherwise known as a Passive-IoT).

(2) Semi-passive (semi-passive) tags, the downstream receiving or upstream reflecting of such tags has a certain amplifying capability;

(3) Tags with active transmission capability (or active Tags) can transmit information to a reader (e.g., reader) independent of reflection of an incoming signal.

The reader-writer, namely the radio frequency tag reader-writer, is one of two important components (tag and reader-writer) of the radio frequency identification system. The radio frequency tag read-write device has other popular names according to specific implementation functions, such as: reader (Reader), interrogator (Communicator), scanner (Scanner), reader (Reader and Writer), programmer (Programmer), reading Device (Reading Device), portable Reader (Portable Readout Device), automatic Device identification equipment (Automatic Equipment Identification Device, AEI), etc.

In a backscatter communication system, there are two main link budgets, namely a forward link and a backscatter link budget, which can affect backscatter communication system performance. In particular, the forward link budget is defined as the amount of power received by the backscatter transmitter, and the backscatter link budget is the amount of power received by the backscatter receiver.

Backscatter communication systems can be divided into three main types: a single-base backscatter communication system (i.e., monostatic Backscatter Communication System, MBCS), a double-base backscatter communication system (Bistatic Backscatter Communication System, BBCS) and a surrounding backscatter communication system (Ambient Backscatter Communication System, ABCS), as shown in fig. 2a, 2b, and 2 c.

2. Regarding the symbiotic backscatter communication transport method:

according to the symbiotic backscatter (Symbiotic Backscatter) principle, bistatic backscatter communications are generally considered by the animal networking (Passive IoT) signaling scenario. If a typical node base station (the next Generation Node B, gNB) and a terminal (e.g., user Equipment (UE)) in a conventional cellular network are considered and a passive internet of things device (i.e., tag) is introduced into the cellular network, two scenarios can be mainly considered, namely, UE assisted by an animal networking scenario.

Scenario-1: the gNB transmits a Primary Signal, and the UE receives the Primary Signal and the Tag reflected Signal. The Tag reflected Signal is modulated by a main Signal received by the Tag and a Secondary Signal (Secondary Signal) transmitted by the Tag, wherein the main Signal is denoted by x [ n ], and the Secondary Signal is denoted by Bm.

Scenario-2: the UE transmits a main signal, and the gNB receives the main signal and a Tag reflection signal. The Tag reflected signal is modulated by the main signal received by the Tag and the auxiliary signal sent by the Tag, wherein the main signal is represented by x [ n ], and the auxiliary signal is represented by B [ m ].

The embodiment of the present application described below is exemplified by scenario-1. Scene-2 and scene-1 can be generalized to the same scene, with the implementation of scene-2 being similar to that of scene-1, as shown in FIG. 3. The transmitting end (Tx) may be a gNB or UE, and the receiving end (Rx) may be a corresponding UE or gNB. In order to achieve an intuitive technical explanation, in the following description, tx is unified as gNB and Rx is unified as UE.

Thus, when the gNB transmits the primary signal x [ n ], the signal y [ n ] received by the UE can be expressed as:

y[n]＝(h ₂ +h ₃ B[m])x[n]+w[n]

wherein h is ₂ Is the gNB to UE channel response, h ₃ Is the channel response of gNB reflected to UE by Tag, n and m are the indexes of the main signal and the auxiliary signal symbols, n=0, 1, …, NM-1; m=0, 1, …, M-1, andm is the number of symbols of the secondary signal and N is the number of primary signals in each modulated secondary signal, named secondary signal modulation block, as shown in fig. 4.

It is noted that the primary signal x n may be transmitted by any waveform such as code division multiple access (Code Division Multiple Access, CDMA), time division multiple access (Time Division Multiple Access, TDMA), orthogonal frequency division multiplexing (Orthogonal Frequency Division Multiplexing, OFDM), etc.

The UE receiving end needs to detect the main signal x [ n ] and the auxiliary signal B [ m ]. The UE receiving end generally uses a coherent reception algorithm, and may be a Maximum Likelihood estimation (ML) detection algorithm, a Linear detection algorithm (Linear Detector) or a detection algorithm based on serial interference cancellation (Successive Interference Cancellation, SIC). The joint detection of the primary signal x [ n ] and the secondary signal B [ m ] can be accomplished using these algorithms, but these algorithms have problems of high complexity or low system performance.

3. Regarding the Passive IoT signal transmission method with beamforming:

if the gNB knows the direction or location of the Tag, the gNB can implement Passive IoT signaling using beamforming methods, as shown in fig. 5.

The signal, y n, received by the beamformed UE may be approximated as

y[n]≈h ₃ B[m]x[n]+w[n]

It can be seen that the benefit of utilizing beamforming to achieve Passive IoT signaling is to increase Tag communication range and effectively improve energy harvesting. However, in order to implement beamforming, the Tag needs to be located, which increases the complexity of the transmitting end. Typically this approach is used for Passive IoT traffic with higher quality of service (Quality of Service, qoS) requirements.

The terminal referred to in the present application may be a mobile phone, a tablet (Tablet Personal Computer), a Laptop (Laptop Computer) or a terminal-side Device called a notebook, a personal digital assistant (Personal Digital Assistant, PDA), a palm top, a netbook, an ultra-mobile personal Computer (ultra-mobile personal Computer, UMPC), a mobile internet appliance (Mobile Internet Device, MID), an augmented reality (augmented reality, AR)/Virtual Reality (VR) Device, a robot, a Wearable Device (weather Device), a vehicle-mounted Device (VUE), a pedestrian terminal (PUE), a smart home (home Device with a wireless communication function, such as a refrigerator, a television, a washing machine, or furniture, etc.), a game machine, a personal Computer (personal Computer, PC), a teller machine, or a self-service machine, etc., and the Wearable Device includes: intelligent wrist-watch, intelligent bracelet, intelligent earphone, intelligent glasses, intelligent ornament (intelligent bracelet, intelligent ring, intelligent necklace, intelligent anklet, intelligent foot chain etc.), intelligent wrist strap, intelligent clothing etc.. In addition to the above terminal device, the terminal related to the present application may also be a Chip in the terminal, such as a Modem (Modem) Chip, a System on Chip (SoC). It should be noted that, the embodiment of the present application is not limited to a specific type of terminal.

The network-side device referred to in the present application may comprise an access network device or a core network device, where the access network device may also be referred to as a radio access network device, a radio access network (Radio Access Network, RAN), a radio access network function or a radio access network element. The access network device may include a base station, a WLAN access point, a WiFi node, or the like, where the base station may be referred to as a node B, an evolved node B (eNB), an access point, a base transceiver station (Base Transceiver Station, BTS), a radio base station, a radio transceiver, a basic service set (Basic Service Set, BSS), an extended service set (Extended Service Set, ESS), a home node B, a home evolved node B, a transmission receiving point (Transmitting Receiving Point, TRP), or some other suitable terminology in the field, and the base station is not limited to a specific technical vocabulary so long as the same technical effect is achieved, and it should be noted that in the embodiment of the present application, only the base station in the NR system is described by way of example, and the specific type of the base station is not limited.

The backscatter communication processing method, apparatus, communication device and readable storage medium provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings by some embodiments and application scenarios thereof.

Referring to fig. 6, an embodiment of the present application provides a method for processing backscatter communication, which is applied to a first device, where the first device may also be referred to as a transmitting end, and the first device may be a network side device or a terminal, and specific steps include: step 601.

Step 601: the first device transmits first information related to the backscatter communication, the first information being indicative of any one of:

(1) The transmission waveform of the main signal is a Single-Carrier signal waveform, and the transmission waveform of the auxiliary signal is a Single-Carrier signal waveform;

(2) The transmission waveform of the main signal is a single Carrier signal waveform, and the transmission waveform of the auxiliary signal is a Multi-Carrier signal waveform;

(3) The transmission waveform of the main signal is a multi-carrier signal waveform, and the transmission waveform of the auxiliary signal is a single-carrier signal waveform;

(4) The transmission waveform of the main signal is a multi-carrier signal waveform, and the transmission waveform of the auxiliary signal is a multi-carrier signal waveform.

The secondary signal may also be referred to as a secondary signal.

It will be appreciated that the transmission waveform of the secondary signal may be efficiently selected and designed in this application based on the transmission waveform of the primary signal, such as a single carrier signal waveform or a multi-carrier signal waveform.

In one embodiment of the present application, the method further comprises:

in the case that the transmission waveform of the main signal is a single carrier signal waveform, and the transmission waveform of the auxiliary signal is a single carrier signal waveform, or in the case that the transmission waveform of the main signal is a multi-carrier signal waveform, and the transmission waveform of the auxiliary signal is a single carrier signal waveform, the first device sets a reference signal in each modulation block in a time domain signal related to the main signal.

In one embodiment of the present application, the method further comprises:

in the case where the transmission waveform of the main signal is a single carrier signal waveform, the transmission waveform of the auxiliary signal is a multi-carrier signal waveform, or in the case where the transmission waveform of the main signal is a multi-carrier signal waveform, the first device sets a reference signal in each modulation block in a frequency domain signal related to the main signal.

In one embodiment of the present application, the length of the reference signal is determined by a maximum length of a multipath channel between the first device and the backscatter communication device.

In one embodiment of the present application, in the case where the maximum length of the multipath channel is kχΔ, the length of the reference signal in each modulation block is (k+d) ×Δ, K and d are integers greater than or equal to 1, d represents the number of effective reference signals, and Δ is the delay path difference between the second delay path and the first delay path of the multipath channel.

In one embodiment of the present application, the modulation block is composed of a minimum communication transmission time domain resource element or a frequency domain resource element.

In one embodiment of the present application, the minimum communication transmission frequency domain resource element is an orthogonal frequency division multiplexing OFDM subcarrier.

In one embodiment of the present application, the method further comprises:

the first device transmits the main signal, and the transmission waveform of the main signal is a single-carrier signal waveform or a multi-carrier signal waveform.

In one embodiment of the present application, the first device includes a network side device or a terminal.

In one embodiment of the present application, the primary signal is a signal transmitted by a first device and the secondary signal is a signal transmitted by a backscatter communication device.

Referring to fig. 7, an embodiment of the present application provides a backscatter communication processing method, applied to a backscatter communication device, such as a Tag, including the following specific steps: step 701.

Step 701: the backscatter communication device receives first information relating to backscatter communication, the first information being indicative of any one of:

(1) The transmission waveform of the main signal is a single carrier signal waveform, and the transmission waveform of the auxiliary signal is a single carrier signal waveform;

In one embodiment of the present application, the method further comprises:

the back scattering communication device receives a main signal from a first device, wherein the transmission waveform of the main signal is a single-carrier signal waveform or a multi-carrier signal waveform;

the backscatter communication equipment determines a transmission waveform of an auxiliary signal according to the first information;

the back-scattering communication equipment modulates the main signal and the auxiliary signal to obtain a back-scattering signal;

The backscatter communication device transmits the backscatter signal to a second device.

In one embodiment of the present application, the determining, by the backscatter communication device, a transmission waveform of the secondary signal according to the first information includes:

the backscatter communication device determines a transmission waveform of the secondary signal based on the first information and a capability of the backscatter communication device and/or a channel type between the backscatter communication device and the second device.

In one embodiment of the present application, the modulating, by the backscatter communication device, the primary signal and the secondary signal to obtain a backscatter signal includes:

the backscattering communication equipment carries out time domain modulation according to a time domain signal related to the main signal and the auxiliary signal to obtain a backscattering signal;

the transmission waveform of the main signal is a single carrier signal waveform, the transmission waveform of the auxiliary signal is a single carrier signal waveform, or the transmission waveform of the main signal is a multi-carrier signal waveform, and the transmission waveform of the auxiliary signal is a single carrier signal waveform.

In one embodiment of the present application, the backscattering communication apparatus performs time domain modulation according to a time domain signal related to a main signal and an auxiliary signal to obtain a backscattering signal, including:

The backscatter communication devices insert reference signals into each time domain modulation block in the time domain signals related to the main signals to obtain target time domain signals;

the backscattering communication equipment carries out time domain modulation on the target time domain signal and the auxiliary signal to obtain a backscattering signal;

the transmission waveform of the main signal is a single carrier signal waveform, and the transmission waveform of the auxiliary signal is a single carrier signal waveform.

In one embodiment of the present application, the length of the reference signal is determined by a maximum length of a multipath channel between the first device and the backscatter communication device;

or,

the length of the reference signal is greater than or equal to a difference between a shortest delay path and a longest delay path of a first multipath channel, the first multipath channel comprising a multipath channel between the first device and the backscatter communication device, and a multipath channel between the backscatter communication device and the second device.

In one embodiment of the present application, the backscattering communication apparatus performs modulation in a time domain according to a time domain signal related to a main signal and an auxiliary signal to obtain a backscattering signal, including:

The backscatter communication device inserts a Cyclic Prefix (CP) into a time domain signal associated with the main signal to obtain a target time domain signal;

the transmission waveform of the main signal is a multi-carrier signal waveform, and the transmission waveform of the auxiliary signal is a single-carrier signal waveform.

In one embodiment of the present application, the secondary signal has a length that is an integer multiple of the OFDM symbol length.

In one embodiment of the present application, the length of the cyclic prefix CP is greater than or equal to the sum of the first value and the second value;

wherein the first value is equal to a difference between a shortest delay path and a longest delay path of a multipath channel between the first device and a backscatter communication device, and the second value is equal to a difference between a shortest delay path and a longest delay path of a multipath channel between the backscatter communication device and the second device.

The backscattering communication equipment carries out frequency domain modulation according to a frequency domain signal related to the main signal and the auxiliary signal to obtain a backscattering signal;

the transmission waveform of the main signal is a single carrier signal waveform, the transmission waveform of the auxiliary signal is a multi-carrier signal waveform, or the transmission waveform of the main signal is a multi-carrier signal waveform, and the transmission waveform of the auxiliary signal is a multi-carrier signal waveform.

In one embodiment of the present application, the backscattering communication apparatus performs frequency domain modulation according to a frequency domain signal related to a main signal and an auxiliary signal to obtain a backscattering signal, including:

the backscattering communication equipment performs Discrete Fourier Transform (DFT) processing and cyclic prefix CP removal processing on a frequency domain signal related to the main signal to obtain a target frequency domain signal;

the backscatter communication device inserts a reference signal and a new cyclic prefix CP into the target frequency domain signal and modulates the secondary signal to obtain a backscatter signal.

In the embodiment of the application, the transmission waveforms of the main signal and the auxiliary signal are configured through the first information, so that the mutual fusion and effective transmission of the main signal and the auxiliary signal are realized, the receiving end (namely the second equipment) can simply and effectively demodulate the main signal and the auxiliary signal at the same time, and the transmission efficiency of symbiotic back scattering communication is improved.

Referring to fig. 8, an embodiment of the present application provides a method for processing backscatter communication, which is applied to a second device, where the second device may also be referred to as a receiving end, for example, the second device may include a terminal or a network side device, and specific steps include: step 801.

Step 801: the second device receives first information related to backscatter communications, the first information being indicative of at least one of:

In one embodiment of the present application, the method further comprises:

the second device receives a main signal from the first device, and the transmission waveform of the main signal is a single-carrier signal waveform or a multi-carrier signal waveform.

In one embodiment of the present application, the method further comprises:

The second device receives a backscatter signal from a backscatter communication device, the backscatter signal being modulated by the primary signal and the secondary signal.

It will be appreciated that the second device may process the backscattered signal according to the first information, demodulate the primary signal and the secondary signal, and the related description may refer to the fourth embodiment and the fifth embodiment.

In one embodiment of the present application, after step 801, the method may further include: steps 802 and 803 (not shown).

Step 802: the second equipment acquires a main signal, carries out coherent demodulation and decoding processing on the main signal according to a reference signal in the main signal to obtain data in the main signal, wherein the main signal comprises M modulation blocks, each modulation block comprises K first reference signals, K is more than or equal to 1 and less than or equal to N, N is the number of resource units contained in each modulation block, K is a positive integer, N is more than or equal to 2, and M and N are positive integers.

Step 803: and the second equipment acquires a symbiotic back-scattering modulation block, carries out coherent demodulation processing on the symbiotic back-scattering modulation block according to the main signal, and obtains data in the auxiliary signal, wherein M is a positive integer.

Optionally, the symbiotic backscatter modulation block includes a modulated secondary signal and a noise signal.

It should be noted that in the embodiment of the present application, the main signal may be acquired first and then the symbiotic backscatter modulation block may be acquired first, or the symbiotic backscatter modulation block may be acquired first and then the main signal may be acquired, or the main signal and the symbiotic backscatter modulation block may be acquired simultaneously. In addition, in the embodiment of the application, when the signal is processed, the main signal is demodulated, and then the symbiotic backscattering modulation block is demodulated according to the demodulated main signal.

In the embodiment of the application, the second device can simply and effectively perform coherent demodulation and decoding processing on the main signal according to the reference signal in the main signal, and further can demodulate the secondary signal according to the data of the demodulated main signal, thereby achieving the purpose of simply demodulating the main signal and the auxiliary signal in the symbiotic backscattering communication signal.

Optionally, performing coherent demodulation and decoding processing on the main signal according to a reference signal in the main signal to obtain data in the main signal, where the method includes:

performing coherent demodulation on the main signal according to a reference signal in the main signal to obtain a main signal estimated value;

And carrying out bit decoding processing on the main signal estimated value through a channel decoder to obtain data (namely main signal data bit information) in the main signal.

Optionally, the modulated auxiliary signals are obtained by modulating M auxiliary signals by a main signal, where the M auxiliary signals include one second reference signal, or include two second reference signals with the same length and opposite phases;

and performing coherent demodulation processing on the modulated secondary signal according to the primary signal to obtain data in an auxiliary signal, wherein the data comprises:

copying the main signal to obtain a copied main signal;

performing weighted average processing on the symbiotic backscattering modulation block through the copied main signal to obtain a processed symbiotic backscattering modulation block;

and performing coherent demodulation processing on the processed symbiotic backscattering modulation block according to the second reference signal in the processed symbiotic backscattering modulation block to obtain data in the auxiliary signal.

For a better understanding of the embodiments of the present application, the following description is made in connection with examples one to seven.

The method and the device realize mutual fusion and effective transmission of the main signal and the auxiliary signal mainly through the design of symbiotic back scattering communication signal waveforms. In particular, in the multipath channel scenario, the symbiotic backscattering communication main signal transmission may use a single carrier signal waveform or a multi-carrier signal waveform, and the symbiotic backscattering communication auxiliary signal transmission may effectively design its own transmission waveform according to the transmission waveform of the main signal.

More specifically, when the main signal uses a single carrier signal waveform or a multi-carrier signal waveform, the auxiliary signal may use a single carrier signal waveform. The carrier signal waveform of the auxiliary signal can ensure the performance of the receiving end in the single-path channel scene. In the scene of multipath channel, the receiving end can only demodulate the symbiotic backscattering communication signal by taking the channel path with the maximum signal strength as the reference point of time in the demodulation process, and the signals on other channel paths can only be considered as interference signals, so that the demodulation performance can not be ensured.

To solve the problem of demodulation of the symbiotic backscatter communication signal by the multipath channel, effectively, the primary signal uses a multi-carrier orthogonal frequency division multiplexing (Orthogonal Frequency Division Multiplexing, OFDM) signal waveform, and the secondary signal also uses a multi-carrier OFDM signal waveform. The method comprises the steps of eliminating the influence of multipath channels in a back-scattering communication device by utilizing the inherent multipath channel resistance of OFDM, modulating a back-scattering signal on a frequency domain of an auxiliary signal, adding a cyclic prefix CP, and reflecting the back-scattering signal. The advantage of modulating the symbiotic backscatter communication signal with the OFDM carrier signal waveform is to effectively combat the effects of multipath fading, thereby improving the transmission efficiency of the symbiotic backscatter communication.

It should be noted that the present application is mainly described with respect to centralized symbiotic backscatter communications, but the techniques in the present application can be extended to other scenarios, such as split symbiotic backscatter communications.

Embodiment one: symbiotic backscattering communication carrier wave bearing mode

The carrier-to-carrier configuration of the gNB (or UE) and the carrier-to-carrier configuration of the Tag are shown in table 1. As can be seen from table 1, the combination of carrier-bearing configurations is not too limited, but the carrier-bearing configuration relationship goodness of fit varies from an implementation point of view. When the gcb (or UE) configuration uses a single carrier, the carrier bearer configuration of the Tag may depend on the single carrier bearer (i.e., carrier bearer option one) or on the multi-carrier bearer (i.e., carrier bearer option two). When the gNB (or UE) configuration uses multiple carriers, the carrier bearer configuration of the Tag may be dependent on either a single carrier bearer (i.e., carrier bearer option three) or a multiple carrier bearer (i.e., carrier bearer option four).

The excellent meaning that the carrier bearer configuration relationship between the gNB (or UE) and the Tag is the most consistent. Meaning that the carrier-bearer configuration relationship of the gNB (or UE) and Tag may be employed, but is not the best pairing.

Notably, for carrier bearing option three, since the primary signal is modulated by a single carrier and the secondary signal is modulated by multiple carriers, the time domain signal associated with the primary signal must be added with a cyclic prefix CP and then transmitted. This has the advantage that, as with OFDM signals, the receiving end can simply demodulate the signal by means of a frequency domain equalizer (Frequency Equalization). The frequency domain equalizer technique is not described in detail in this application.

Each carrier bearing option has certain characteristics. The Tag selection carrier bearer option is a carrier bearer that depends on the configuration of the gcb (or UE) for the primary signal. When the permission of the Tag is low and the channel characteristics are mainly LoS channel (i.e., single-path channel), the Tag selects carrier one or carrier three. However, in case the allowed capability of the Tag is relatively high and the channel characteristics are dominated by the NLoS channel (i.e. multipath channel), the Tag may select either carrier-bearing option two or carrier-bearing option four.

Notably, if carrier-bearing option one and carrier-bearing option three are selected, the gNB (or UE) needs to be equipped with a complex equalizer as the receiving end to demodulate the symbiotic back-scattered signal of the multipath channel. This is generally the case for QoS traffic that requires relatively low levels. However, if carrier two and carrier four are selected, the gNB (or UE) need only be equipped with a single-order equalizer (Single Tap Equalization) as the receiving end to demodulate the symbiotic backscatter signal of the multipath channel by countering the characteristics of the multipath channel by OFDM, so as to provide overall symbiotic backscatter communication performance. This is typically the case for relatively high-demand QoS traffic.

Table 1 carrier bearer configuration relationship of the gnb (or UE) and Tag.

	Single carrier wave Tag	Multicarrier Tag
			Single carrier gNB (or UE)	Carrier bearing option one	Carrier bearing option two:good
Multicarrier gNB (or UE)	Carrier bearing option three:good	Carrier bearing option four: excellent

Embodiment two: symbiotic backscatter communication signal waveform design for carrier-bearing option one and carrier-bearing option three

In accordance with one illustration of an embodiment, the primary signal x [ n ] is a modulation symbol based on quadrature amplitude modulation (Quadrature Amplitude Modulation, QAM) carried by a single-carrier or multi-carrier transmission waveform, and the secondary signal B [ m ] is a modulation symbol based on binary phase shift keying (Binary Phase Shift Keying, BPSK) carried by a single-carrier or multi-carrier transmission waveform.

Notably, the secondary signal may also carry QAM-based modulation symbols, but the technical description in this application proceeds primarily with BPSK modulation methods, taking into account the complexity limitations allowed by the Tag (or Backscatter Device) in the Passive IoT application. However, all the techniques referred to in this application can be simply extended for all modulation methods, such as On-Off Keying (OOK), QAM, etc.

Fig. 9a and 9b are schematic diagrams of modulation of a primary signal and a secondary signal in the time domain based on a single carrier. Specifically, the primary signal x [ N ] is composed of time domain Modulation blocks (Modulation blocks) of length N, each of which is composed of minimum communication transmission time domain resource elements, such as single carrier pulses (pulses), wherein the time domain Modulation blocks n=4 as shown in fig. 9a and 9 b. The primary signal x n is transmitted from the gNB, received by the Tag, modulated by BPSK and generates a secondary signal waveform, which is finally back-scattered.

It is noted that the size of the modulation block N may be signaled to the UE by the gNB via Layer 1 (Layer 1, L1) signaling or MAC-CE signaling, or may be configured via radio resource control (Radio Resource Control, RRC).

It is noted that in a single carrier signal waveform design, the transmit waveform used for the primary signal may be a single carrier signal waveform or a multi-carrier signal waveform, but the backscatter transmit waveform for the secondary signal is a single carrier signal waveform. As shown in table 1, carrier one and carrier three are of a single carrier signal waveform for backscatter transmission.

As shown in fig. 9a, the gNB transmits the primary signal on a single-path channel, receives and modulates the secondary signal by the Tag with a delay τ, and finally back-scatters the time-domain modulated signal to the UE.

As shown in fig. 9b, the gNB transmits the primary signal over the multipath channel, receives and modulates the secondary signal by the Tag with a delay τ, and finally back-scatters the time-domain modulated signal to the UE. For simplicity of illustration, the difference between the first path and the first delay path of the multipath channel is Δ, which is considered as the granularity of the multipath channel as is the pulse length of the single carrier.

Here, it is explained how to modulate the main signal, the auxiliary signal and the back-scattered time domain modulated signal according to the multipath channel. Specifically, the primary signal x (t) is sent from gNB, received by Tag, and may be denoted as h _1,l x(t-τ _1,l ). The auxiliary signal is modulated on the received signal h _1,l x(t-τ _1,l ) In which h is _1,l Is the first multipath Channel Response (Channel Response) between gNB and Tag, τ _1,l Is the first multipath channel delay. That is, the signal h is received _1,l x (t) is the transmission auxiliary signal Bm as a communication propagation carrier]. Thus, the single carrier back-scattered signal of the secondary signal can be expressed as equation (1):

wherein p is _T (t) is the pulse waveform of the backscatter signal, L ₁ Is the channel multipath number between gNB and Tag, τ _1,l Is the first path delay of the channel multipath between gNB to Tag, n and m are the indices of the primary and secondary signal symbols, respectively, and w (t) is the additive white Gaussian noise (Additive White Gaussian Noise, AWGN) noise.

Alternatively, deltaτ ₁ May be Deltaτ ₁ ＝τ _1,1 X (t) is a time domain signal, which may be a single carrier signal waveform or a multi-carrier signal waveform (e.g., OFDM waveform).

Notably, when Δτ ₁ ＝τ _1,1 The secondary signal modulation time is the first path delay of the aligned multipath channel.

It should be noted that, if the modulation of the main signal is based on a single carrier signal waveform, the main signal and the auxiliary signal modulation method based on the single carrier in the time domain can only work normally if the number of channel multipaths is small (for example, line of sight (LoS) is a scene), and the delay difference of different multipaths is small. If the scene is a non-line of sight (Non Line of sight, NLoS) scene and the delay difference of different multipaths is relatively large, the UE cannot acquire the complete reference signal and thus cannot demodulate the main signal data because the reference signals received on the different multipaths are staggered by the multipath channels in the time domain. In NLoS scenarios, the length of the reference signal needs to be lengthened, e.g. effectively configured according to the maximum length of the multipath channel.

Effectively, if the maximum length of the multipath channel delay is kΔ, then the length of the reference signal in each modulation block is (k+d) Δ, i.e., the reference signal occupies pulses of k+d single carriers, or k+d OFDM samples, where d is the number of valid reference signals, an integer greater than or equal to 1, i.e., d≡1.

Notably, since the reference signal used in the multipath channel is increased by K, the primary signal transmission effectiveness is reduced

As shown in fig. 10, the gNB determines the length of the reference signal according to the maximum length of the multipath channel delay, wherein since the maximum length of the multipath channel delay is kΔ, k=1, the number of effective reference signals d=1 can be simply configured here, and the length of the reference signal is 2Δ, i.e., the reference signal occupies 2 pulses of a single carrier, or 2 OFDM samples.

As shown in fig. 10, the Tag decides a time point of modulation of the auxiliary signal according to a delay of the multipath channel, and modulates the auxiliary signal on the received main signal. Tag is a time-modulated secondary signal according to a first delay path of a multipath channel. Since the second delay path and the first delay path of the multipath channel differ by a, the signal from gNB to Tag is flipped by the modulation phase of the Tag auxiliary signal, the validity of the reference signal is reduced by half, i.e. only one reference signal pulse is considered by the UE as valid reference signal.

The UE may perform the cancellation of the secondary signal phase of the received signal according to the effective reference signal, and then effectively demodulate the data information of the primary signal through a reception algorithm such as an equalizer.

In addition, if the modulation of the main signal is based on the waveform of the multi-carrier signal, in the case of directly modulating the auxiliary signal in the time domain, the channel multipath channel through gNB to Tag is the multipath channel since the phase of some OFDM samples in the OFDM symbol is reversed, and the signal to the UE is also the multipath channel, so that the channel frequency selectivity (Channel Frequency Selectivity) through the Tag backscatter signal is enlarged, and the orthogonality of the OFDM signal of the main signal is destroyed. Therefore, to maintain the orthogonality of the OFDM signal of the main signal, the length of the auxiliary signal must be an integer multiple of the OFDM symbol length. In this way, no additional reference signal is needed, as long as by inserting enough cyclic prefix CP. Specifically, the cyclic prefix CP has a length at least equal to K ₁ Δ+K ₂ Delta, where K ₁ Delta is the difference between the shortest delay path and the longest delay path of the Tag-UE multipath channel, K ₂ Delta is the difference between the shortest and longest delay paths of the Tag-UE multipath channel. The specific description is set forth in detail in example six.

In addition, if the gNB-Tag channel is a multipath channel and the Tag-UE is also a multipath channel, the length of the reference signal is at least equal to the difference between the shortest delay path and the longest delay path of the gNB-Tag-UE synthesized multipath channel. Specifically, the difference K between the shortest delay path and the longest delay path of gNB-Tag multipath channel ₁ Delta, and the difference K between the shortest delay path and the longest delay path of the Tag-UE multipath channel ₂ Delta, the length of the reference signal is at least equal to (K ₁ +K ₂ ) Delta, i.e. the length of the configuration reference signal is K ₁ +K ₂ +d single carrier pulse lengths, where d is the number of active reference signals and d is an integer greater than or equal to 1, i.e., d+.1.

Alternatively, in the case where the channel characteristics are mainly LoS channels (i.e., single-path channels), the Tag may effectively select a single carrier signal waveform, i.e., carrier-bearing option one, or carrier-bearing option three, in consideration of transmission availability of the main signal.

Embodiment III: the co-occurrence backscatter communication signal waveform design Tag for carrier two and carrier four options may BPSK modulate and backscatter secondary signal B m using a multi-carrier signal waveform (e.g., OFDM waveform). But this requires that the multicarrier signal waveform used by the main signal is an OFDM waveform. I.e. carrier bearer option four as shown in table 1.

Note that in the second carrier bearing option, although the primary signal is a signal transmitted by a single carrier method, since the cyclic prefix CP is inserted into the time domain signal, the waveform design of the symbiotic backscattering communication signal can be modulated in the frequency domain as in the fourth carrier bearing option. Not described in detail in this application.

The advantage of using OFDM waveform to BPSK modulate the secondary signal Bm and back scatter is that multipath fading effect can be effectively counteracted, thus improving the receiving performance of UE to the back scatter signal.

Fig. 11 shows a schematic diagram of modulation of a primary signal and a secondary signal in the frequency domain based on an OFDM carrier. Specifically, the received main signal is a time domain signal having an OFDM waveform. Tag receives OFDM time domain signal h _1,l x(t-τ _1,l ) And converts the time domain signal into a frequency domain signal. There are two methods for converting a time domain signal into a frequency domain signal. One is to directly convert the time domain analog signal into a frequency domain signal by fourier transformation (Fourier Transform, FT). The other is to convert the time domain analog signal into a time domain digital signal and then convert the time domain digital signal into a frequency domain signal by discrete fourier transform (Discrete Fourier Transform, DFT). The difference between the two is different implementation methods, and the obtained frequency domain signals are not different. The received frequency domain signal after being converted is expressed as formula (2):

Wherein,is a DFT function of length Q, q=0, 1, …, Q-1, and Q is the OFDM symbol length, q=mn, p _T And (t) is the carrier waveform of the main signal, and w (t) is the AWGN noise.

Specifically, the frequency domain main signal X [ q ] is divided by Modulation blocks (Modulation blocks) of length N, each Modulation Block being composed of minimum communication transmission frequency domain resource elements, such as OFDM subcarriers (OFDM carriers). Tag BPSK-modulates on the frequency domain main signal xq and generates an auxiliary signal frequency domain signal waveform, which can be expressed as formula (3):

X _B [q]＝B[m]P _T [q]X[q]

wherein P is _T [q]Is the waveform of the backscattered signal in the frequency domain, is a Floor Function (i.e., floor Function), q=0, 1, …, Q-1.

Then Tag computes the frequency domain signal X through IDFT _B [q]Converted into a time domain signal x _B [t]Expressed as a formula(4)：

Wherein,is an IDFT function of length Q, q=0, 1, …, Q-1, and Q is the OFDM symbol length, q=mn.

Finally, OFDM time domain signal x _B (t) backscattered by Tag to UE.

Notably, the effect of gNB-to-Tag channel multipath is first eliminated due to the Tag passing through the DFT process, plus the cyclic prefix CP removal process. Then, the auxiliary signal is modulated by the OFDM waveform, and then the cyclic prefix CP is added again to carry out IDFT processing, so that the influence of the whole channel multipath can be completely eliminated when the UE demodulates the main signal, thereby effectively resisting the multipath fading effect and improving the receiving performance of the UE on the back scattering signal.

Embodiment four: demodulation mode for single carrier signal

The single carrier signal demodulation method is performed by selection of carrier bearing option one and carrier bearing option three.

For symbiotic back scattering single carrier signals, the Tag does not need DFT and IDFT processing, and the signal modulation of the Tag directly carries out time domain processing on the received main signal, so the complexity of the Tag is relatively low. This symbiotic backscattering approach can be regarded as an instant symbiotic backscattering system.

In the case where the gNB transmits the main signal using the omni-directional antenna, the symbiotic back-scattered multi-carrier signal y (t) received by the UE is expressed as formula (5):

wherein L is ₂ Is the number of multipath channels between gNB and UE, L ₃ Is the number of channel multipaths from Tag to UE, τ _2,l Is gNB to UThe first multipath channel response between E, τ _3,l Is the first multipath channel response between Tag to UE,the single carrier backscatter signal, which is an auxiliary signal, is defined in equation 1, w [ t ]]Is AWGN noise.

In the case where the gNB transmits the main signal using the beamforming antenna, the symbiotic backscattered multicarrier signal y (t) received by the UE is approximated as equation (6):

demodulation of x [ n ] for UE]And B [ m ]]Simply assume in this application that the channel is a single-path channel (i.e., L ₂ ＝L ₃ =1), the gNB transmits the main signal with an omni-directional antenna, so the digital signal after passing through an Analog-to-digital converter (ADC) can be simply expressed as formula (7):

y[n]＝(h ₂ +h ₃ B[m])x[n]+w[n]

wherein h is ₂ Is the channel response between gNB and Tag, h ₃ Is the Tag-to-UE channel response.

If it is simply assumed that the reference signal occupies the first resource element of each modulation block, the UE divides the received signal y [ n ] by y [1], and the obtained demodulation symbol of the main signal can be expressed as formula (8):

where n=2, 3, …, N.

If it is simply assumed that the transmitted reference signal is 1, i.e., x [1] =1, the demodulation symbol of the UE can be simplified to formula (9):

it is thus apparent that by setting a reference signal per modulation block, the UE can demodulate the primary signal data symbolsFinally, the main signal is decoded by the Channel Decoder to obtain the main signal data bit information +.>

Using the digital bit information of the main signal decoded in embodiment twoCopy primary signal symbol->Then, by copying the main signal symbol +.>The UE first performs +_on each symbiotic backscatter modulation block received>Weighted average processing, i.e., formula (10): />

Notably, the estimated primary signal And duplicated main signal symbol->Are different. The former has a higher bit error rate and the latter typically has a very low bit error rate due to the channel decoding gain.

Assuming that the main signal digital symbol demodulation error rate is very small and negligible, the weighted averaged symbiotic backscatter modulation block signal can be approximated as equation (11):

wherein,is AWGN noise after being weighted-averaged.

For demodulation of auxiliary signals, every M auxiliary signals, two reference signals with the same length (the length is P) and opposite phases are inserted, wherein P is an integer, and P is more than or equal to 1 and less than M/2. Optionally, in the first P symbol, tag is modulated on the backscatter reference signal with B [ m ] =1. In the second P symbol, tag is modulated on the backscatter reference signal with B m = -1. Among the remaining symbols, tag modulates the backscattered data symbol B m.

With the reference signal in the first P symbol, the UE can simply acquire the following signals:

while with the reference signal in the second P symbol, the UE can simply acquire the following:

by solving the equation consisting of equation (12) and equation (13), the UE can acquire the channel response h ₂ And h ₃ . Finally, the UE may demodulate the secondary signal data symbols Bm according to equation (11) ]Where m=2p+1, …, M.

It is noted that for demodulation performance of the main signal data symbols, the channel coding gain can be improved by reducing the Code Rate (Code Rate) of the main signal data symbols. And for demodulation performance of the secondary signal data symbols, the Processing Gain (Processing Gain) can be increased by selecting a larger modulation block N value.

It is noted that if the gNB uses beamforming to transmit the primary signal, the secondary signal data symbols B M can be effectively demodulated by only inserting the reference signal in the first P symbol for every M secondary signals, since the gain of the gNB to UE link is so small that it can be ignored.

Fifth embodiment: demodulation method for multi-carrier signal

The multi-carrier signal demodulation method is executed through the selection of the carrier bearing option two or the carrier bearing option four.

Fig. 11 shows a modulation process of a main signal (including a reference signal) and an auxiliary signal in the frequency domain based on a multi-carrier signal waveform. Wherein the primary signal modulation blocks n=4, and each primary signal modulation block is inserted with one resource element as a reference signal. Specifically, the gNB inserts a reference signal on the frequency domain main signal, i.e., inserts one reference signal resource element (i.e., k=1) every three main signal resource elements, thereby forming one frequency domain modulation block with a length n=4.

Specifically, gNB transmits the primary signal x [ n ]]Received by the Tag. Tag first receives signal h _1,l X (t) performs DFT operation to convert the time domain signal into frequency domain signal X q]. And then BPSK modulation is carried out on the auxiliary signal data symbols on the frequency domain, an auxiliary signal multi-carrier signal waveform is generated, IDFT operation is carried out, and finally backscattering is carried out.

Notably, the Tag multi-carrier signal waveform modulation of the secondary signal data symbols is primarily directed to combat multipath fading effects. For symbiotic backscatter multicarrier signals (e.g., OFDM signals), the Tag needs to be DFT and IDFT processed, and thus the complexity of the Tag is relatively high. In addition, since the processing time delay of DFT and IDFT is at least one OFDM symbol length, this symbiotic backscattering method can be regarded as a non-instantaneous symbiotic backscattering system.

In the case where the gNB transmits the main signal using the omni-directional antenna, the symbiotic back-scattered multi-carrier signal y (t) received by the UE is expressed as formula (14):

wherein L is ₂ Is the number of multipath channels between gNB and UE, L ₃ Is the number of channel multipaths from Tag to UE, τ _2,l Is the first multipath channel response between gNB and UE, τ _3,l Is the first multipath channel response between Tag and UE, x _B (t) is the single carrier backscatter signal of the secondary signal, defined in equation (4), w [ t ] ]Is AWGN noise, T _Proc Is the total processing time of the Tag receiving end on DFT and IDFT of the received signal.

In the case where the gNB transmits the main signal using the beamforming antenna, the symbiotic back-scattered multicarrier signal y (t) received by the UE reception end is approximated as formula (15):

here, the frequency domain primary signal X q is demodulated for the UE receiving end]And a frequency domain primary signal Bm]And consider simply that the gNB transmits the primary signal with an omni-directional antenna. For simplicity, the total processing time T of DFT and IDFT of the received signal by the Tag receiving end _Proc Set to zero. In addition, if the gNB is considered to transmit the primary signal using an omni-directional antenna, the UE receiving end is a pre-known pre-OFDM symbol. Therefore, the UE receiving end detects X q]And B [ m ]]The received signal terms of the gNB-UE link may be effectively eliminated before.

Thus performing a DFT operation on equation (14), the resulting digital signal can be simply expressed as equation (16):

Y[q]＝(H ₂ +H ₃ B[m])X[q]+W[q]

wherein, is a bottom taking letterNumber (i.e. Floor Function), W [ q]Is AWGN noise in the frequency domain.

If it is simply assumed that the reference signal occupies the first resource element of each modulation block, the demodulation symbol of the primary signal by the UE can be expressed as formula (17):

where q=2, 3, …, N.

If it is simply assumed that the transmitted reference signal is 1, i.e., X [1] =1, the demodulation symbol of the UE can be simplified to formula (18):

Digital bit information using the above decoded main signalReproducing the primary signal symbol X q]. Then, by copying the main signal symbol X q]The UE first X-s each symbiotic backscatter modulation block received ^* [n]Weighted average processing, i.e. X is performed on equation (16) ^* [q]Weighted average processing expressed as formula (19):

worth of itNote that the estimated primary signalAnd the copied primary signal symbol X q]Are different. The former has a higher bit error rate and the latter typically has a very low bit error rate due to the channel decoding gain.

Assuming that the primary signal digital symbol demodulation error rate is very small and negligible, the weighted averaged symbiotic backscatter modulation block signal can be approximated as equation (20):

wherein,is AWGN noise after being weighted-averaged.

For demodulation of auxiliary signals, every M auxiliary signals, two reference signals with the same length (the length is P) and opposite phases are inserted, wherein P is an integer, and P is more than or equal to 1 and less than M/2.

Alternatively, in the first P symbol, the Tag is modulated on the back-scattered reference signal with B [ m ] = -1, and in the second P symbol, the Tag is modulated on the back-scattered reference signal with B [ m ] = -1. Among the remaining symbols, tag modulates the backscattered data symbol B m.

Thus, with the reference signal in the first P symbol, the UE can simply average over the P symbol and obtain the following signals:

similarly, with the reference signal in the second P symbol, the UE may simply average the P symbols to obtain the following signals:

by solving the equation consisting of equation (21) and equation (22), the UE can acquire the channel response H ₂ And H ₃ . Finally, the UE may demodulate the secondary signal data symbols Bm according to equation (20)]Where m=2p+1, …, M.

It is noted that for demodulation performance of the main signal data symbols, the channel coding gain can be improved by reducing the Code Rate (i.e., code Rate) of the main signal data symbols. And for demodulation performance of the secondary signal data symbols, the Processing Gain (Processing Gain) can be increased by selecting a larger modulation block N value.

Example six: single carrier correlated Tag received signal and transmitted signal

When the main signal uses a multi-carrier signal waveform and the auxiliary signal uses a single-carrier signal waveform (i.e., carrier bearing option three), the Tag can effectively select a method that the auxiliary signal length is an integer multiple of the OFDM symbol length, effectively utilize the cyclic prefix CP function of OFDM, reduce the burden of the time domain reference signal and improve the transmission efficiency of symbiotic back scattering communication.

Shown in fig. 12 is a schematic modulation scheme based on an OFDM carrier primary signal and on a single carrier secondary signal. Wherein the length of the secondary signal is equal to the length of the OFDM symbol, and the length of the OFDM symbol is 9 (including a cyclic prefix CP with a length of one). In this embodiment, the number of multipath channels is 2, and the two multipath delay differences are one OFDM sample. In case the main signal does not require an additional time domain reference signal, the Tag can modulate the auxiliary signal on the received time domain main signal. Specifically, the Tag is in the modulation process, and the modulation time of the auxiliary signal is the first path delay of the aligned multipath channel or the last path delay of the aligned multipath channel. As shown in fig. 12, the secondary signal modulation time is aligned with the first path delay of the multipath channel. Modulating the secondary signal by the time domain primary signal will phase flip the primary signal. However, the UE receiving end removes the cyclic prefix CP before performing DFT, so that the phase inversion of the secondary signal to the primary signal can be regarded as the phase of the multipath channel, and no influence is generated on the data demodulation of the primary signal.

Notably, in this embodiment, the channel from Tag to UE is assumed to be a single-path channel.

If the channel from Tag to UE is a multipath channel, the cyclic prefix CP length of the primary signal must take into account the total maximum multipath channel delay length from gNB to Tag to UE.

The present embodiment considers the gNB-Tag multipath channel and the Tag-UE multipath channel. FIG. 13a shows a two-path channel of gNB-Tag, where the 2-path delay difference is one OFDM sample, i.e., Δ; fig. 13b shows a two-path channel for Tag-UE, where the 2-path delay difference is two OFDM samples, i.e. 2Δ; fig. 13c shows the gNB-Tag-UE composite multipath channel.

Specifically, the OFDM length of the main signal transmitted from the gNB is 13, including the cyclic prefix CP length. Since the difference between the shortest delay path and the longest delay path of the gNB-Tag-UE composite multipath channel is 3 delta, the cyclic prefix CP length of the main signal is set to at least 3 OFDM sample lengths. In the present embodiment, as shown in fig. 14a, the OFDM-CP length of the main signal is set to 3 OFDM samples.

As shown in fig. 14a, 14b and 14c, the main signal transmitted from the gNB is received by the Tag through the gNB-Tag multipath channel shown in fig. 13a, and the sub signal of the Tag is modulated on the received signal, as shown in fig. 14 a. Notably, the secondary signal has a length equal to the OFDM symbol length.

More specifically, the signal modulated by the Tag auxiliary signal is reflected by the Tag, received by the UE through the Tag-UE multipath channel shown in fig. 13b, as shown in fig. 14 b. After the UE performs cyclic prefix CP removal processing on the OFDM symbol, a main signal demodulation signal is obtained, as shown in fig. 14 c.

More specifically, the main signal demodulation signal as shown in fig. 14c is a signal having a cyclic function characteristic, to which the Tag auxiliary signal has no influence. Therefore, the UE can finish removing the influence caused by the multipath channel through DFT operation.

Notably, the efficiency of symbiotic backscatter communications is higher than that of secondary signals with shorter lengths, since there is no need to additionally insert time domain reference signals. However, a disadvantage is that there are two options regarding the length of the primary and secondary signals in order to achieve that the secondary signal is an integer multiple of the OFDM symbol.

Alternatively, a very short OFDM symbol may be selected so that the secondary signal transmission rate may be increased. However, since a cyclic prefix CP of the maximum multipath channel delay length of the gNB-Tag-UE composite multipath channel must be inserted into the OFDM symbol, the transmission rate of the main signal may not be improved.

Option two, a longer OFDM symbol may be selected so that the transmission rate of the primary signal may be increased. The length of the secondary signal is at least equal to the length of the primary signal, so that the data transfer rate of the secondary signal cannot be increased.

In this case, therefore, the lengths of the primary and secondary signals can be effectively configured according to the service-related QoS of the two signals.

Embodiment seven: multicarrier-related Tag received signal and transmitted signal

The present embodiment relates to a modulation process for a main signal reception signal and a generated backscatter signal. In this embodiment, the primary signal is modulated by an OFDM waveform, and the secondary signal is also modulated by an OFDM waveform, i.e., the carrier signal waveform selected in this embodiment is of carrier bearing option four.

The signal representation and characteristics at each location at the Tag receiving end are different. Fig. 15 shows the received signal at four different signal points.

At the receiving end (1) point of the Tag, as illustrated in scheme three, the time domain primary signal sent by the receiving gNB of the Tag can be expressed as formula (23):

wherein p is _T (t) is the pulse waveform of the backscatter signal, L ₁ Is the channel multipath number between gNB and Tag, τ _1,l Is the first path delay, w, of the channel multipath between gNB and Tag _r And (t) is AWGN noise.

At the modulation end (2) point of Tag, the time domain signal is converted into the frequency domain signal through DFT, and then the cyclic prefix CP is removed, so that the frequency domain signal can be expressed as formula (24):

wherein,is a DFT function of length Q, q=0, 1, …, Q-1, and Q is the OFDM symbol length, q=mn.

At the modulation end (3) point of Tag, the frequency domain main signal X [ q ] is divided by modulation blocks with length N, wherein each modulation block is composed of minimum communication transmission frequency domain resource element OFDM sub-carrier, including reference signal and data signal. Tag BPSK-modulates on the frequency domain main signal xq and generates an auxiliary signal frequency domain signal waveform, which can be expressed as formula (25):

X _B [q]＝B[m]P _T [q]X[q]

wherein P is _T [q]Is the waveform of the backscattered signal in the frequency domain, is a ground Function (i.e., floor Function).

At the point of the modulation end (4) of the Tag, the Tag adds the cyclic prefix CP to the frequency domain signal again to process, and the frequency domain signal X is processed by IDFT operation _B [q]Converted into a time domain signal x _B [t]Expressed as formula (26):

OFDM time domain signal x _B (t) backscattered by Tag to UE.

Notably, the effect of gNB-to-Tag channel multipath is first eliminated due to the Tag passing through the DFT process, plus the cyclic prefix CP removal process. Then, the auxiliary signal is modulated by the OFDM waveform, and then the cyclic prefix CP is added again to carry out IDFT processing, so that the influence of the whole channel multipath can be completely eliminated when the UE terminal demodulates the main signal, and the receiving terminal does not generate any interference signal, thereby effectively resisting the multipath fading effect and improving the receiving performance of the UE on the back scattering signal.

Referring to fig. 16, an embodiment of the present application provides a backscatter communications processing apparatus, applied to a first device, the apparatus 1600 includes:

a first transmitting module 1601 configured to transmit first information related to backscatter communication, the first information being configured to indicate any one of:

In one embodiment of the present application, the apparatus 1600 further comprises:

the first configuration module is configured to set a reference signal in each modulation block in a time domain signal related to the main signal when the transmission waveform of the main signal is a single carrier signal waveform, and the transmission waveform of the auxiliary signal is a single carrier signal waveform, or when the transmission waveform of the main signal is a multi-carrier signal waveform, and the transmission waveform of the auxiliary signal is a single carrier signal waveform.

and the second configuration module is used for setting a reference signal in each modulation block in the frequency domain signal related to the main signal when the transmission waveform of the main signal is a single-carrier signal waveform and the transmission waveform of the auxiliary signal is a multi-carrier signal waveform or when the transmission waveform of the main signal is a multi-carrier signal waveform.

In one embodiment of the present application, in the case where the maximum length of the multipath channel is kxΔ, the length of the reference signal in each modulation block is (k+d) ×Δ, K and d are integers greater than or equal to 1, d represents the number of effective reference signals, and Δ represents the delay path difference between the second delay path and the first delay path of the multipath channel.

and the second transmitting module is used for transmitting the main signal, and the transmission waveform of the main signal is a single-carrier signal waveform or a multi-carrier signal waveform.

The device provided in the embodiment of the present application can implement each process implemented by the embodiment of the method of fig. 6, and achieve the same technical effects, so that repetition is avoided, and no further description is provided herein.

Referring to fig. 17, an embodiment of the present application provides a backscatter communication processing apparatus, applied to a backscatter communication device, such as a tag, apparatus 1700 includes:

a first receiving module 1701, configured to receive first information related to backscatter communications, where the first information is configured to indicate any one of:

In one embodiment of the present application, the apparatus 1700 further comprises:

the second receiving module is used for receiving a main signal from the first equipment, and the transmission waveform of the main signal is a single-carrier signal waveform or a multi-carrier signal waveform;

the determining module is used for determining the transmission waveform of the auxiliary signal according to the first information;

the modulation module is used for modulating the main signal and the auxiliary signal to obtain a back scattering signal;

and a third sending module, configured to send the backscatter signal to a second device.

In one embodiment of the present application, the determining module is further configured to:

determining a transmission waveform of the secondary signal according to the first information and the capability of the back-scattering communication device and/or the channel type between the back-scattering communication device and the second device.

In one embodiment of the present application, the modulation module is further configured to:

modulating in the time domain according to a time domain signal related to the main signal and the auxiliary signal to obtain a back scattering signal;

inserting a reference signal into each time domain modulation block in the time domain signals related to the main signal to obtain a target time domain signal;

modulating the target time domain signal and the auxiliary signal in the time domain to obtain a back scattering signal;

or,

inserting a cyclic prefix CP into a time domain signal related to the main signal to obtain a target time domain signal;

performing Discrete Fourier Transform (DFT) processing and cyclic prefix CP removal processing on a frequency domain signal related to the main signal to obtain a target frequency domain signal;

and inserting a reference signal and a new cyclic prefix CP into the target frequency domain signal, and modulating an auxiliary signal to obtain a back scattering signal.

The device provided in this embodiment of the present application can implement each process implemented by the method embodiment of fig. 7, and achieve the same technical effects, so that repetition is avoided, and no further description is provided herein.

Referring to fig. 18, an embodiment of the present application provides a backscatter communication processing apparatus, applied to a second device, apparatus 1800 includes:

a third receiving module 1801, configured to receive first information related to backscatter communications, where the first information is used to indicate at least one of:

In one embodiment of the present application, the apparatus 1800 further comprises:

and the fourth receiving module is used for receiving the main signal from the first equipment, and the transmission waveform of the main signal is a single-carrier signal waveform or a multi-carrier signal waveform.

and a fifth receiving module, configured to receive a back-scattered signal from a back-scattered communication device, where the back-scattered signal is modulated by the main signal and the auxiliary signal.

The device provided in the embodiment of the present application can implement each process implemented by the embodiment of the method of fig. 8, and achieve the same technical effects, so that repetition is avoided, and no further description is provided herein.

Fig. 19 is a schematic diagram of a hardware structure of a terminal for implementing an embodiment of the present application. The terminal 1900 includes, but is not limited to: at least some of the components of the radio frequency unit 1901, the network module 1902, the audio output unit 1903, the input unit 1904, the sensor 1905, the display unit 1906, the user input unit 1907, the interface unit 1908, the memory 1909, and the processor 1940, etc.

Those skilled in the art will appreciate that terminal 1900 may also include a power source (e.g., a battery) for powering the various components, which may be logically connected to processor 1940 via a power management system so as to perform functions such as managing charge, discharge, and power consumption via the power management system. The terminal structure shown in fig. 19 does not constitute a limitation of the terminal, and the terminal may include more or less components than shown, or may combine some components, or may be arranged in different components, which will not be described in detail herein.

It should be appreciated that in embodiments of the present application, the input unit 1904 may include a graphics processing unit (Graphics Processing Unit, GPU) 19041 and a microphone 19042, with the graphics processor 19041 processing image data of still pictures or video obtained by an image capturing device (e.g., a camera) in a video capturing mode or an image capturing mode. The display unit 1906 may include a display panel 19061, and the display panel 19061 may be configured in the form of a liquid crystal display, an organic light emitting diode, or the like. The user input unit 507 includes at least one of a touch panel 19071 and other input devices 19072. Touch panel 19071, also referred to as a touch screen. Touch panel 19071 may include two parts, a touch detection device and a touch controller. Other input devices 19072 may include, but are not limited to, a physical keyboard, function keys (e.g., volume control keys, switch keys, etc.), a trackball, a mouse, a joystick, and so forth, which are not described in detail herein.

In this embodiment, after receiving downlink data from the network side device, the radio frequency unit 1901 may transmit the downlink data to the processor 1940 for processing; in addition, the radio frequency unit 1901 may send uplink data to the network side device. Typically, the radio frequency unit 1901 includes, but is not limited to, an antenna, an amplifier, a transceiver, a coupler, a low noise amplifier, a duplexer, and the like.

Memory 1909 may be used to store software programs or instructions and various data. The memory 1909 may mainly include a first memory area storing programs or instructions and a second memory area storing data, wherein the first memory area may store an operating system, application programs or instructions (such as a sound playing function, an image playing function, etc.) required for at least one function, and the like. Further, the memory 1909 may include volatile memory or nonvolatile memory, or the memory 1909 may include both volatile and nonvolatile memory. The nonvolatile Memory may be a Read-Only Memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an Electrically Erasable EPROM (EEPROM), or a flash Memory. The volatile memory may be random access memory (Random Access Memory, RAM), static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double Data Rate SDRAM (ddr SDRAM), enhanced SDRAM (Enhanced SDRAM), synchronous DRAM (SLDRAM), and Direct RAM (DRRAM). Memory 1909 in embodiments of the present application includes, but is not limited to, these and any other suitable types of memory.

Processor 1940 may include one or more processing units; optionally, the processor 1940 integrates an application processor that primarily processes operations involving an operating system, user interface, application programs, and the like, and a modem processor that primarily processes wireless communication signals, such as a baseband processor. It will be appreciated that the modem processor described above may not be integrated into the processor 1940.

The terminal provided in the embodiment of the present application can implement each process implemented by the embodiments of the method in fig. 6, fig. 7 or fig. 8, and achieve the same technical effects, so that repetition is avoided, and no further description is given here.

Referring to fig. 20, fig. 20 is a block diagram of a communication device applied to an embodiment of the present application, and as shown in fig. 20, a communication device 2000 includes: processor 2001, transceiver 2002, memory 2003 and bus interface, wherein processor 2001 may be responsible for managing the bus architecture and general processing. The memory 2003 may store data used by the processor 2001 in performing operations.

In one embodiment of the present application, the communication device 2000 further comprises: a program stored in the memory 2003 and executable on the processor 2001, which when executed by the processor 2001, performs the steps in the method shown in fig. 6, 7 or 8 above.

In fig. 20, the bus architecture may include any number of interconnecting buses and bridges, and in particular one or more processors represented by the processor 2001 and various circuits of memory represented by the memory 2003, linked together. The bus architecture may also link together various other circuits such as peripheral devices, voltage regulators, power management circuits, etc., which are well known in the art and, therefore, will not be described further herein. The bus interface provides an interface. The transceiver 2002 may be a number of elements, i.e. include a transmitter and a receiver, providing a means for communicating with various other apparatus over a transmission medium.

Optionally, as shown in fig. 21, the embodiment of the present application further provides a communication device 2100, including a processor 2101 and a memory 2102, where the memory 2102 stores a program or an instruction that can be executed on the processor 2101, for example, when the communication device 2100 is a terminal, the program or the instruction is executed by the processor 2101 to implement each step of the method embodiment of fig. 6, and the same technical effects can be achieved, so that repetition is avoided and no further description is given here; when the communication device 2100 is a backscatter communication device, the program or instructions, when executed by the processor 2101, implement the steps of the method embodiment of fig. 7, and achieve the same technical effects, and are not repeated herein; when the communication device 2100 is a network-side device, the program or the instructions when executed by the processor 2101 implement the steps of the method embodiment of fig. 8, and achieve the same technical effects, and are not repeated herein.

The embodiment of the present application further provides a readable storage medium, where a program or an instruction is stored, and when the program or the instruction is executed by a processor, the method of fig. 6, fig. 7, or fig. 8 and each process of each embodiment described above are implemented, and the same technical effects can be achieved, so that repetition is avoided, and no further description is provided herein.

Wherein the processor is a processor in the terminal described in the above embodiment. The readable storage medium may be non-volatile or non-transitory. The readable storage medium may include a computer readable storage medium such as a computer read only memory ROM, a random access memory RAM, a magnetic or optical disk, etc.

The embodiment of the application further provides a chip, the chip includes a processor and a communication interface, the communication interface is coupled to the processor, and the processor is configured to run a program or instructions, implement each process of each method embodiment shown in fig. 6, fig. 7 or fig. 8 and described above, and achieve the same technical effect, so that repetition is avoided, and no further description is provided here.

It should be understood that the chips referred to in the embodiments of the present application may also be referred to as system-on-chip chips, or the like.

Embodiments of the present application further provide a computer program/program product stored in a storage medium, where the computer program/program product is executed by at least one processor to implement the respective processes of the respective method embodiments shown in fig. 6, fig. 7, or fig. 8 and described above, and achieve the same technical effects, and for avoiding repetition, a detailed description is omitted herein.

The embodiment of the present application further provides a communication system, where the communication system includes a network side device, a terminal, and a backscatter communication device, where the terminal is configured to execute each process of each method embodiment shown in fig. 6 and described above, the network side device is configured to execute each process of each method embodiment shown in fig. 8 and described above, and the backscatter communication device is configured to execute each process of each method embodiment shown in fig. 7 and described above, and achieve the same technical effect, so that repetition is avoided and no further description is given here.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element. Furthermore, it should be noted that the scope of the methods and apparatus in the embodiments of the present application is not limited to performing the functions in the order shown or discussed, but may also include performing the functions in a substantially simultaneous manner or in an opposite order depending on the functions involved, e.g., the described methods may be performed in an order different from that described, and various steps may also be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

From the above description of the embodiments, it will be clear to those skilled in the art that the above-described embodiment method may be implemented by means of software plus a necessary general hardware platform, but of course may also be implemented by means of hardware, but in many cases the former is a preferred embodiment. Based on such understanding, the technical solutions of the present application may be embodied essentially or in a part contributing to the prior art in the form of a computer software product stored in a storage medium (such as ROM/RAM, magnetic disk, optical disk), comprising several instructions for causing a terminal (which may be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to perform the method described in the embodiments of the present application.

The embodiments of the present application have been described above with reference to the accompanying drawings, but the present application is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many forms may be made by those of ordinary skill in the art without departing from the spirit of the present application and the scope of the claims, which are also within the protection of the present application.

Claims

1. A backscatter communication processing method, comprising:

2. The method according to claim 1, wherein the method further comprises:

3. The method according to claim 1, wherein the method further comprises:

4. A method according to claim 2 or 3, characterized in that the length of the reference signal is determined by the maximum length of a multipath channel between the first device and the backscatter communication device.

5. The method of claim 4, wherein in the case where the maximum length of the multipath channel is kχΔ, the length of the reference signal in each modulation block is (k+d) χΔ, K and d are integers greater than or equal to 1, d represents the number of valid reference signals, and Δ represents the difference between the delay paths of the second delay path and the first delay path of the multipath channel.

6. A method according to claim 2 or 3, characterized in that the modulation block consists of minimum communication transmission time domain resource elements or frequency domain resource elements.

7. The method of claim 6, wherein the minimum communication transmission frequency domain resource element is an orthogonal frequency division multiplexing, OFDM, subcarrier.

8. The method according to claim 1, wherein the method further comprises:

9. A method according to any one of claims 1 to 8, wherein the primary signal is a signal transmitted by the first device and the secondary signal is a signal transmitted by a backscatter communication device.

10. The method according to any of claims 1 to 8, wherein the first device comprises a network side device or a terminal.

11. A backscatter communication processing method, comprising:

12. The method of claim 11, wherein the method further comprises:

13. The method of claim 12, wherein the backscatter communication device determines a transmission waveform of a secondary signal based on the first information, comprising:

14. The method of claim 12, wherein the modulating the primary signal and the secondary signal by the backscatter communication device results in a backscatter signal, comprising:

15. The method of claim 14, wherein the backscatter communication device time-domain modulates a backscatter signal from a time-domain signal associated with the primary signal and the secondary signal, comprising:

16. The method of claim 15, wherein the length of the reference signal is determined by a maximum length of a multipath channel between the first device and the backscatter communication device;

or,

17. The method of claim 14, wherein the backscatter communication device time-domain modulates a time-domain signal associated with the primary signal and the secondary signal to obtain a backscatter signal, comprising:

the backscatter communication device inserts a cyclic prefix CP in a time domain signal associated with the primary signal to obtain a target time domain signal;

18. The method of claim 17 wherein the secondary signal has a length that is an integer multiple of the OFDM symbol length.

19. The method of claim 17, wherein the length of the cyclic prefix CP is greater than or equal to a sum of a first value and a second value;

20. The method of claim 12, wherein the modulating the primary signal and the secondary signal by the backscatter communication device results in a backscatter signal, comprising:

21. The method of claim 20, wherein the backscatter communication device frequency domain modulates the backscatter signal based on the frequency domain signal associated with the primary signal and the secondary signal, comprising:

22. A method according to any of claims 11 to 21, wherein the primary signal is a signal transmitted by a first device and the secondary signal is a signal transmitted by a backscatter communication device.

23. The method of any of claims 11-21, wherein the backscatter communication device comprises a tag.

24. A backscatter communication processing method, comprising:

25. The method of claim 24, wherein the method further comprises:

26. The method of claim 24, wherein the method further comprises:

27. A method according to any one of claims 24 to 26, wherein the primary signal is a signal transmitted by a first device and the secondary signal is a signal transmitted by a backscatter communication device.

28. A method according to any of claims 24 to 26, wherein the second device comprises a network side device or a terminal.

29. A backscatter communication processing apparatus for use with a first device, comprising:

30. A backscatter communication processing apparatus for use with a backscatter communication device, comprising:

31. A backscatter communication processing apparatus for use with a second device, comprising:

32. A communication device comprising a processor, a memory and a program or instruction stored on the memory and executable on the processor, which when executed by the processor implements the steps of the method of any of claims 1 to 28.

33. A readable storage medium, characterized in that it has stored thereon a program or instructions which, when executed by a processor, implement the steps of the method according to any of claims 1 to 28.