Back reflection communication method and device

Abstract

The present application provides a back reflection communication method and apparatus, the method comprising: a first device generates a back reflection signal of a background signal, and the background signal is a signal transmitted by a second device. The first device sends the back reflection signal of the background signal using a back reflection communication method. Among them, the duration of a modulation symbol of the back reflection signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the signal estimation unit, and N is an integer greater than or equal to 1. Based on this, since the change of the background signal by the back reflection signal is in units of the duration of the channel estimation unit, although the back reflection signal changes the amplitude or phase of the background signal, since the change of the background signal in one or more channel estimation units is constant, this change can be obtained through channel estimation, thereby eliminating the influence of the back reflection signal on the normal transmission of the background signal.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a back reflection communication method and device. Background Art

[0002] Modulated backscatter technology has the characteristics of low cost and low power consumption. It is different from traditional communication technology. The transmitter using modulated backscatter technology does not generate radio frequency (RF) signals itself, but sends data by modulating the RF signals in the environment. The RF signals in the environment include excitation signals dedicated to the transmitter for reflection, and background signals in the environment. The background signals can be wireless TV signals, broadcast signals, signals sent by mobile communication stations, signals sent by access points (AP), signals sent by dedicated card readers, etc.

[0003] The modulation backscattering technology that transmits data by reflecting the RF signal in the modulation environment can be called back reflection communication. Back reflection communication by reflecting the background signal has the following advantages: no special excitation signal needs to be sent, and the background signal does not need to occupy a dedicated frequency band. Therefore, back reflection communication is suitable for the field of Internet of Things (IoT) communication.

[0004] However, since the transmitter changes the characteristics of the background signal when reflecting the background signal, it may affect the normal transmission of the original information in the background signal. Summary of the invention

[0005] The present application provides a back reflection communication method and device, thereby avoiding or reducing the impact of back reflection signals on the normal transmission of background signals.

[0006] In a first aspect, the present application provides a back reflection communication method, comprising: a first device generates a back reflection signal of a background signal, where the background signal is a signal transmitted by a second device. The first device sends the back reflection signal of the background signal using a back reflection communication method. The duration of a modulation symbol of the back reflection signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the signal estimation unit, and N is an integer greater than or equal to 1.

[0007] In a second aspect, the present application provides a back reflection communication method, comprising: a first device receives a background signal transmitted by a second device, and the background signal carries a back reflection signal sent to the first device. The first device parses the back reflection signal. The duration of a modulation symbol of the back reflection signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the signal estimation unit, and N is an integer greater than or equal to 1.

[0008] The back-reflection communication method provided in the present application has the following technical effects: although the back-reflection signal changes the amplitude or phase of the background signal, since the change of the background signal in one or more channel estimation units is constant, this change can be obtained through channel estimation, thereby eliminating the influence of the back-reflection signal on the normal transmission of the background signal.

[0009] Optionally, the background signal includes: a physical layer preamble and a data field, and the data field includes at least one signal estimation unit.

[0010] The channel estimation unit includes a channel estimation field and at least one data symbol adjacent to the channel estimation field. That is, when the background signal is a signal using a WiFi-like pilot structure, and the background signal includes a constructed channel estimation unit, since the duration of a modulation symbol of the back-reflected signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the signal estimation unit, based on this, since the change of the background signal in one or more channel estimation units is constant, this change can be obtained through channel estimation, thereby eliminating the influence of the back-reflected signal on the normal transmission of the background signal.

[0011] Optionally, the data field includes a data portion and a padding portion, and the physical layer preamble of the background signal includes a first length indication and a second length indication, wherein the first length indication is used to indicate the length of the data portion, and the second length indication is used to indicate the length of the padding portion, so that the first device can parse the data field according to the first length indication and the second length indication.

[0012] Optionally, the modulation mode of the back reflection signal is QPSK, BPSK or OOK.

[0013] Optionally, when the background signal is a signal using an LTE-like pilot structure, the channel estimation unit includes a plurality of symbols, each symbol including at least one pilot subcarrier, and the pilot subcarrier is used for channel estimation. That is, when the background signal is a signal using an LTE-like pilot structure, and the background signal includes the channel estimation unit, since the duration of a modulation symbol of the back-reflected signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the signal estimation unit, based on this, although the back-reflected signal changes the amplitude or phase of the background signal, since the change of the background signal in one or more channel estimation units is constant, this change can be obtained through channel estimation, thereby eliminating the influence of the back-reflected signal on the normal transmission of the background signal.

[0014] Optionally, the pilot subcarriers on multiple symbols are evenly distributed on the multiple symbols.

[0015] In a third aspect, the present application provides a back reflection communication method, including: a first device generates a back reflection signal of a background signal, and the background signal is a signal transmitted by a second device. The first device sends the back reflection signal of the background signal using a back reflection communication method. Among them, the data symbol in the background signal includes a pilot subcarrier for estimating the phase deviation, the duration of a modulation symbol of the back reflection signal is N times the duration of a data symbol, and the modulation symbol is aligned with the time start position of the data symbol, and N is an integer greater than or equal to 1.

[0016] In a fourth aspect, the present application provides a back reflection communication method, comprising: a first device receives a background signal transmitted by a second device, and the background signal carries a back reflection signal sent to the first device. The first device parses the back reflection signal. The data symbol in the background signal includes a pilot subcarrier for estimating a phase deviation, the duration of a modulation symbol of the back reflection signal is N times the duration of a data symbol, and the modulation symbol is aligned with the time start position of the data symbol, and N is an integer greater than or equal to 1.

[0017] The back-reflection communication method provided in the present application has the following technical effects: although the back-reflection signal changes the phase of the background signal, since the change of the background signal within one or more data symbols is constant, this change can be obtained through phase deviation estimation, thereby eliminating the influence of the back-reflection signal on the background signal.

[0018] Optionally, the background signal includes: a physical layer preamble and a data field, and the data field includes at least one data symbol.

[0019] Optionally, the data field includes a data portion and a padding portion, and the physical layer preamble of the background signal includes a first length indication and a second length indication, wherein the first length indication is used to indicate the length of the data portion, and the second length indication is used to indicate the length of the padding portion, so that the first device can parse the data field according to the first length indication and the second length indication.

[0020] Optionally, the back reflection signal is a signal using QPSK or BPSK modulation.

[0021] The following will provide a back reflection communication device, equipment, storage medium and computer program product, which have overlapping contents with the above-mentioned back reflection communication method, and these overlapping contents will not be repeated below.

[0022] In a fifth aspect, the present application provides a back reflection communication device, including:

[0023] The generating module is used to generate a back reflection signal of a background signal, where the background signal is a signal transmitted by the second device.

[0024] The sending module is used to send the back reflection signal of the background signal by adopting the back reflection communication mode.

[0025] The duration of a modulation symbol of the back reflection signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the signal estimation unit, and N is an integer greater than or equal to 1.

[0026] In a sixth aspect, the present application provides a back reflection communication device, including:

[0027] The receiving module is used to receive a background signal transmitted by the second device, where the background signal carries a back-reflection signal sent to the back-reflection communication device.

[0028] The analysis module is used to analyze the back reflection signal.

[0029] The duration of a modulation symbol of the back reflection signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the signal estimation unit, and N is an integer greater than or equal to 1.

[0030] In a seventh aspect, the present application provides a back reflection communication device, including:

[0031] The generating module is used to generate a back reflection signal of a background signal, where the background signal is a signal transmitted by the second device.

[0032] The sending module is used to send the back reflection signal of the background signal by adopting the back reflection communication mode.

[0033] The data symbol in the background signal includes a pilot subcarrier for estimating the phase deviation, the duration of a modulation symbol of the back-reflected signal is N times the duration of a data symbol, and the modulation symbol is aligned with the time starting position of the data symbol, and N is an integer greater than or equal to 1.

[0034] In an eighth aspect, the present application provides a back reflection communication device, including:

[0035] The receiving module is used to receive a background signal transmitted by the second device, where the background signal carries a back-reflection signal sent to the back-reflection communication device.

[0036] The analysis module is used to analyze the back reflection signal.

[0037] The data symbol in the background signal includes a pilot subcarrier for estimating the phase deviation, the duration of a modulation symbol of the back-reflected signal is N times the duration of a data symbol, and the modulation symbol is aligned with the time starting position of the data symbol, and N is an integer greater than or equal to 1.

[0038] In a ninth aspect, the present application provides a back-reflection communication device, comprising: a memory, a processor and a transceiver, the memory storing computer instructions, the transceiver being used for data transmission between other devices, and the processor being used for executing the computer instructions to implement part or all of the back-reflection communication method described in any one of the above aspects or any optional method of any one of the aspects.

[0039] In a tenth aspect, the present application provides a computer storage medium, which includes computer instructions. When the instructions are executed by a computer, the computer implements the back-reflection communication method involved in any one of the above aspects or any optional manner of any one of the aspects.

[0040] In an eleventh aspect, the present application provides a computer program product, which includes instructions. When the computer program is executed by a computer, the instructions enable the computer to implement the back-reflection communication method involved in any one of the above aspects or any optional manner of any one of the aspects.

[0041] The present application provides a back reflection communication method and device, wherein the duration of a modulation symbol of the back reflection signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time starting position of the signal estimation unit, and N is an integer greater than or equal to 1. The change of the back reflection signal to the background signal is in the unit of the duration of the channel estimation unit, so within a channel estimation unit, the channel will not change, so that the change of the back reflection signal to the background signal does not affect the normal reception of the background signal. Alternatively, the data symbol in the background signal includes a pilot subcarrier for estimating the phase deviation, the duration of a modulation symbol of the back reflection signal is N times the duration of a data symbol, and the modulation symbol is aligned with the time starting position of the data symbol, and N is an integer greater than or equal to 1. The change of the back reflection signal to the background signal is in the unit of the duration of the data symbol, so within a data symbol, the phase of the background signal will not change, so that the change of the back reflection signal to the background signal does not affect the normal reception of the background signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1A A schematic diagram of an application scenario provided for an embodiment of the present application;

[0043] Figure 1B A schematic diagram of an application scenario provided for another embodiment of the present application;

[0044] Figure 1C A schematic diagram of an application scenario provided for yet another embodiment of the present application;

[0045] Figure 2 A flowchart of a back reflection communication method provided in one embodiment of the present application;

[0046] Figure 3 A schematic diagram of a back reflection signal and a background signal using a WiFi-like pilot structure provided in an embodiment of the present application;

[0047] Figure 4 A schematic diagram of a back reflection signal and a background signal using a WiFi-like pilot structure provided in another embodiment of the present application;

[0048] Figure 5 A schematic diagram of a background signal using an LTE-style pilot structure provided in an embodiment of the present application;

[0049] Figure 6 A schematic diagram of channel estimation in an LTE communication method provided in an embodiment of the present application;

[0050] Figure 7 A schematic diagram of a back reflection signal and a background signal using an LTE-like pilot structure provided in an embodiment of the present application;

[0051] Figure 8 A schematic diagram of a back reflection signal and a background signal using an LTE-like pilot structure provided in another embodiment of the present application;

[0052] Fig. 9 A schematic diagram of an application scenario provided for another embodiment of the present application;

[0053] Fig.10 A flowchart of a back reflection communication method provided by another embodiment of the present application;

[0054] Fig.11 A schematic diagram of an application scenario provided for another embodiment of the present application;

[0055] Fig.12 A flowchart of a back reflection communication method provided in yet another embodiment of the present application;

[0056] Fig.13 A schematic diagram of a back reflection signal and a background signal using a WiFi-like pilot structure provided in an embodiment of the present application;

[0057] Fig.14 A flowchart of a back reflection communication method provided in yet another embodiment of the present application;

[0058] Fig.15 An interactive flow chart of a back reflection communication method provided in yet another embodiment of the present application;

[0059] Fig.16 A schematic diagram of a back reflection communication device 1600 provided in one embodiment of the present application;

[0060] Fig.17A schematic diagram of a back reflection communication device 1700 provided in one embodiment of the present application;

[0061] Fig.18 A schematic diagram of a back reflection communication device 1800 provided in one embodiment of the present application;

[0062] Fig.19 A schematic diagram of a back reflection communication device 1900 provided in one embodiment of the present application;

[0063] Fig. 20 A schematic diagram of a back-reflection communication device 2000 provided in one embodiment of the present application. DETAILED DESCRIPTION

[0064] As described above, the modulated backscattering technology that reflects the radio frequency signal in the modulation environment to perform backreflection communication can be called backreflection communication. Backreflection communication by reflecting the background signal has the following advantages: there is no need to send a special excitation signal, and the background signal does not need to occupy a dedicated frequency band. Therefore, backreflection communication is suitable for the field of IoT communication. However, since the transmitter changes the characteristics of the background signal when reflecting the background signal, it may affect the normal transmission of the original information in the background signal. The original information can be voice, video, image and other information. It should be noted that the modulated backscattering technology is not only applicable to the field of IoT communication, and therefore, the technical solution of the present application is not only applicable to the field of IoT communication.

[0065] The present application provides a back reflection communication method and device, which can ensure the normal transmission of background signals when back transmission communication is adopted. The network element involved in the present application at least includes: a first device and a second device.

[0066] The first device is a wireless communication device with a back-reflection communication function, which has the ability to send information by modulating the radio frequency signal in the environment, and also has the ability to demodulate the radio frequency signal in the environment to receive signals. Optionally, when the first device acts as a transmitting end, the first device refers to a device that uses a back-reflection communication method to send data. When the first device acts as a receiving end, the first device refers to a device that receives data through a background signal. The first device may also be a passive device, or the first device may be an active device, but has a back-reflection communication function. For example: the first device may be an IoT device in an IoT communication network, for example, a tag in an IoT communication network.

[0067] Optionally, the second device is a device with wireless communication function. The wireless communication device may comply with a wireless communication standard, such as a cellular communication standard or a wireless local area network (WLAN) communication standard. Optionally, the background signal may be a broadcast signal sent by the second device, or a signal communicated between the second device and the third device.

[0068] Optionally, the second device and / or the third device is a wireless communication device with wireless communication function. For example, the second device and / or the third device is a base station (Base Transceiver Station, BTS) in Global System of Mobile communication (GSM) or Code Division Multiple Access (CDMA), or a base station (NodeB, NB) in Wideband Code Division Multiple Access (WCDMA), or an evolved NodeB (eNB), access point (AP) or relay station in LTE network, or a base station in the next generation network (i.e., 5G network), or an AP, station (STA) supporting 802.11 protocol. Optionally, the second device and / or the third device is a terminal device or user equipment, which can be a device that provides voice and / or data connectivity to a user, a handheld device with wireless connection function, or other processing devices connected to a wireless modem. The terminal device can communicate with at least one core network via a radio access network (RAN). The terminal device can be a mobile terminal, such as a mobile phone (or "cellular" phone) and a computer with a mobile terminal, for example, a portable, pocket-sized, handheld, computer-built-in or vehicle-mounted mobile device, which exchanges voice and / or data with the radio access network. The terminal device can also be called a subscriber unit (Subscriber Unit), a subscriber station (Subscriber Station), a mobile station (Mobile Station), a mobile station (Mobile Station), a remote station (Remote Station), an access point (Access Point), a remote terminal (Remote Terminal), an access terminal (Access Terminal), a user terminal (User Terminal), a user agent (User Agent) or a user equipment (User Equipment), which is not limited here.

[0069] Optionally, the communication method between the second device and the third device includes but is not limited to: the second device and the third device adopt a terminal-to-terminal (D2D) communication method, for example, the second device and the third device are both terminal devices. Alternatively, the second device and the third device adopt a cellular communication method, for example, the second device is a base station and the third device is a terminal device, or the second device is a terminal device and the third device is a base station. Alternatively, the second device and the third device adopt a Wireless Fidelity (WiFi) communication method, for example: the second device is an AP and the third device is a STA, or the second device is a STA and the third device is an AP; or the second device and the third device are both APs; or the second device and the third device are both STAs.

[0070] Optionally, the first device may use a back-reflection communication method to send a back-reflection signal of a background signal to the second device or the third device, or may use a back-reflection communication method to send a back-reflection signal of a background signal to a fourth device. The fourth device may be an IoT device in an IoT communication network, which may be a passive device or an active device. Based on this, in combination with the above content, the application scenarios to which the technical solution of the present application is applicable are introduced below. It should be noted that the application scenarios involved in the present application are not limited to the following situations. Of course, the number of the first device, the second device, the third device, and the fourth device involved in the embodiments of the present application are only exemplary.

[0071] Scenario 1: Figure 1A A schematic diagram of an application scenario provided in an embodiment of the present application is shown in FIG. Figure 1A As shown, the scenario involves two network elements, namely a first device 11 and a second device 12. The second device 12 can generate a background signal. The first device 11 sends a back reflection signal to the second device 12 through the background signal, or receives a background signal from the second device 12, and the background signal carries the back reflection signal.

[0072] Scenario 2: Figure 1B A schematic diagram of an application scenario provided for another embodiment of the present application is as follows: Figure 1B As shown, the scenario involves three network elements, namely a first device 11, a second device 12 and a third device 13. A background signal is transmitted between the second device 12 and the third device 13. The background signal may be generated by the second device 12 or the third device 13. The first device 11 sends a back reflection signal to the second device 12 or the third device 13 through the background signal, or receives the background signal from the second device 12 or the third device 13, and the background signal carries the back reflection signal.

[0073] Scenario 3: Figure 1C A schematic diagram of an application scenario provided for another embodiment of the present application is as follows: Figure 1C As shown, the scenario involves four network elements, namely a first device 11, a second device 12, a third device 13 and a fourth device 14. A background signal is transmitted between the second device 12 and the third device 13. The background signal may be generated by the second device 12 or the third device 13. The first device 11 sends a back reflection signal to the fourth device 14 through the background signal.

[0074] Based on any of the above scenarios, the technical solution of this application is described below:

[0075] Figure 2 A flow chart of a back reflection communication method provided in an embodiment of the present application, such as Figure 2 As shown, the method includes the following process:

[0076] Step S201: the first device generates a back reflection signal of a background signal, where the background signal is a signal transmitted by the second device.

[0077] Step S202: The first device sends a back reflection signal of the background signal by back reflection communication, wherein the duration of a modulation symbol of the back reflection signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the signal estimation unit, and N is an integer greater than or equal to 1.

[0078] A symbol obtained after the information in the back reflection signal is modulated is called a modulation symbol, and the duration of one modulation symbol of the back reflection signal is the duration of the modulation symbol.

[0079] Optionally, after the first device detects the background signal, it modulates the information to be sent according to the duration of the background signal channel estimation unit to obtain a back reflection signal, so that the duration of a modulation symbol of the modulated back transmission signal is N times the duration of the channel estimation unit, and sends the background signal so that the modulation symbol is aligned with the time start position of the signal estimation unit. Optionally, the modulation method includes phase modulation and amplitude modulation.

[0080] It should be noted that the background signal may be sent by the second device, or may be sent by the second device to a third device or other devices.

[0081] Optionally, a channel estimation unit refers to the smallest channel estimation unit in the background signal, for example: when the second device communicates with other devices using LTE communication, the channel estimation unit may include multiple orthogonal frequency division multiplexing (OFDM) symbols, each OFDM symbol includes at least one pilot subcarrier, and the pilot subcarrier is used for channel estimation. Alternatively, when the second device communicates with other devices using WiFi communication, the channel estimation unit may include a channel estimation field, and at least one OFDM symbol adjacent to the channel estimation field. The channel estimation field is used for signal estimation, and the channel estimation field may be the MidAmble field in 802.11ax.

[0082] As described above, the second device can communicate with other devices using a cellular communication method or a WiFi communication method. This embodiment mainly introduces the back reflection communication method involved when the second device communicates with other devices using an LTE communication method or a WiFi communication method.

[0083] Option 1: When the second device communicates with other devices using a WiFi communication method, in this case, the background signal adopts a WiFi-like pilot structure. Optionally, the background signal using a WiFi-like pilot structure includes: a physical layer preamble and a data field, and the data field includes at least one signal estimation unit. The channel estimation unit includes a MidAmble, and at least one data symbol adjacent to the MidAmble.

[0084] For example, Figure 3 A schematic diagram of a back reflection signal and a background signal using a WiFi-like pilot structure provided in an embodiment of the present application, such as Figure 3As shown, the background signal includes: a physical layer preamble and a data field, and the data field includes at least one signal estimation unit. Exemplarily, the physical layer preamble includes: a short training field (STF), a long training field (LTF) and a signaling (SIG) field. Among them, STF is a sequence known to the transmitter and the receiver, and is used to synchronize the receiver with the transmitter. LTF is a sequence known to the transmitter and the receiver, and is used for the receiver to perform channel estimation. SIG is a control signaling, which is used to indicate the modulation method, coding method and other information used by the data sent by the transmitter. The data field includes at least one channel estimation unit, each channel estimation unit includes a MidAmble, and at least one data symbol adjacent to the MidAmble (that is, the MidAmble and the following or preceding M OFDM symbols constitute a channel estimation unit, and M is an integer greater than or equal to 1). The data symbol can be an OFDM symbol. Among them, in a channel estimation unit, the MidAmble field is used for channel estimation.

[0085] In the embodiment of the present application, the duration of a modulation symbol of the back-reflected signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the signal estimation unit, and N is an integer greater than or equal to 1. Based on this, although the back-reflected signal changes the amplitude or phase of the background signal, since the change of the background signal in one or more channel estimation units is constant, this change can be obtained through channel estimation, thereby eliminating the influence of the back-reflected signal on the normal transmission of the background signal.

[0086] like Figure 3 As shown, each signal with an amplitude of A1 or A2 is an On-Off Keying (OOK) modulation symbol, and the duration of the OOK modulation symbol is 1 times the duration of a channel estimation unit in the background signal, that is, the duration of the OOK modulation symbol is the same as the duration of a channel estimation unit, and each OOK modulation symbol is aligned with the time starting position of the corresponding signal estimation unit. Similarly, the duration of the BPSK modulation symbol obtained by the BPSK modulation method is 1 times the duration of a channel estimation unit in the background signal, that is, the duration of the BPSK modulation symbol is the same as the duration of a channel estimation unit, and each BPSK modulation symbol is aligned with the time starting position of the corresponding signal estimation unit.

[0087] Based on this, although the back reflection signal changes the amplitude of the background signal (for example, when the back reflection signal adopts the OOK modulation method, the back reflection signal will change the amplitude of the background signal) or the phase (for example, when the back reflection signal adopts the BPSK modulation method, the back reflection signal will change the phase of the background signal), since the change of the background signal in one or more channel estimation units is constant, this change can be obtained through channel estimation, thereby eliminating the influence of the back reflection signal on the normal transmission of the background signal. Exemplarily, Figure 4 A schematic diagram of a back reflection signal and a background signal using a WiFi-like pilot structure provided in another embodiment of the present application, for comparison Figure 3 and Figure 4 , Figure 4 The back reflection signal and the background signal shown do not have the following relationship: the duration of a modulation symbol of the back reflection signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the signal estimation unit. Figure 4 In the example, the energy of the first half of the first channel estimation unit is reduced by the reflection of the first device, while the energy of the second half is enhanced by the reflection of the first device, which leads to a large deviation in the channel estimation, and then causes the background signal to be received incorrectly, or even unable to be received. Figure 3 As shown, the change of the back reflection signal to the background signal is based on the duration of the channel estimation unit, so the change of the back reflection signal to the background signal does not affect the normal reception of the background signal.

[0088] Optionally, the data field of the background signal includes a data portion, and the data portion includes: data sent by the second device. If the transmission duration of the data portion is less than the transmission duration of the back reflection signal, the data field also includes a padding portion. Figure 3As shown, the data field includes 3 channel estimation units, wherein the data part includes the first 2 channel estimation units of the 3 channel estimation units, and the padding part includes the last channel estimation unit of the 3 channel estimation units. Based on this, the physical layer preamble of the background signal also includes information for indicating the length of the data part and the length of the padding part. In one example, the information includes a first length indication and a second length indication, the first length indication is used to indicate the length of the data part, the second length indication is used to indicate the length of the padding part, and the sum of the length of the data part and the length of the padding part is the length of the data field. In another example, the information may include a total length indication and the first length indication, and the total length indication is used to indicate the total length of the data field. In another example, the information may include the total length indication and the second length indication. It should be noted that the "length" here can refer to the length of a byte or the duration. It can be understood that the sum of the length of the data part and the length of the padding part is the length of the data field, so the physical layer preamble can indicate any two of the lengths. In one example, any one length indication can be carried in the L-Length field of the physical layer preamble, and the other length indication can be carried in other fields of the physical layer preamble, such as a newly added field. Alternatively, both length indications are carried in the SIG field.

[0089] Option 2: When the second device communicates with other devices using the LTE communication method, in this case, the background signal adopts an LTE-like pilot structure. Optionally, the background signal using the LTE-like pilot structure includes: multiple OFDM symbols, each OFDM symbol includes at least one pilot subcarrier, and the pilot subcarrier is used for channel estimation. Optionally, the pilot subcarriers on the multiple OFDM symbols are evenly distributed on the multiple OFDM symbols.

[0090] For example, Figure 5 A schematic diagram of a background signal using an LTE-style pilot structure provided in an embodiment of the present application, such as Figure 5 As shown in the figure, each OFDM symbol has data subcarriers and pilot subcarriers. The pilot subcarriers are used to send known signals for the receiving end to perform channel estimation. In order to minimize the pilot overhead, the pilot subcarriers on each OFDM symbol are evenly distributed at a certain interval in the frequency domain, and also have the characteristics of uniform distribution in the time domain.

[0091] Figure 6 A schematic diagram of channel estimation in an LTE communication method provided in an embodiment of the present application is shown in FIG. Figure 6 As shown, one OFDM symbol has 8 subcarriers. For example, 8 OFDM symbols constitute a channel estimation unit, where h i，jrepresents the channel response on the jth subcarrier on the i-th OFDM symbol, for example, h 3，7 It represents the channel response on the 7th subcarrier of the 3rd OFDM symbol.

[0092] First, since the signal sent on the pilot subcarrier is a known signal, the channel corresponding to the pilot subcarrier can be estimated, which is h 1，1 ,h 1，5 ,h 3，1 ,h 3，5 ,h 5，1 ,h 5，5 ,h 7，1 ,h 7，5 .

[0093] Secondly, the channels on all subcarriers corresponding to the pilot subcarrier are calculated by time domain interpolation. For example, for the first subcarrier, h 1，1 ,h 5，1 Interpolation to obtain h 1，1 ,h 2，1 ,…,h 4，1 and h 5，1 ,h 6，1 ,…,h 8，1 , and so on.

[0094] Usually, the first-order linear interpolation method can be used for time domain difference, as follows:

[0095] Assuming the first subcarrier, the channel response on different OFDM symbols can be expressed as: i，1 =α*i+β, where i is the sequence number of the OFDM symbol.

[0096] Through the known h 1，1 ,h 1，5 You can get: 1，1 =α*1+β,h 5，1 =α*5+β, thus we can get

[0097] According to α, β and formula h i，1 =α*i+β, the remaining h can be obtained 2，1 ,h 3，1 ,h 4，1 and h 6，1，7，1 ,h 8，1 result.

[0098] Based on this, we obtain the channel estimation results of all OFDM symbols on the 1st, 3rd, 5th, and 7th subcarriers through time domain interpolation. Then, we obtain the channel estimation results on other subcarriers through interpolation on each OFDM symbol based on the channel estimation results that have been obtained. The implementation of the interpolation method is similar to time domain interpolation, for example

[0099] In the embodiment of the present application, the duration of a modulation symbol of the back reflection signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the signal estimation unit, and N is an integer greater than or equal to 1. For example, taking a channel estimation unit including 4 OFDM symbols as an example, Figure 7 A schematic diagram of a back reflection signal and a background signal using an LTE-like pilot structure provided in an embodiment of the present application, such as Figure 7 As shown, the amplitude of an OOK modulation symbol can be A1 or A2, and the duration of the OOK modulation symbol is 1 times the duration of a channel estimation unit in the background signal, that is, the duration of the OOK modulation symbol is the same as the duration of a channel estimation unit, and each OOK modulation symbol is aligned with the time starting position of the corresponding signal estimation unit. Similarly, the phase of a BPSK modulation symbol can be +1 or -1, and the duration of the BPSK modulation symbol is 1 times the duration of a channel estimation unit in the background signal, that is, the duration of the BPSK modulation symbol is the same as the duration of a channel estimation unit, and each BPSK modulation symbol is aligned with the time starting position of the corresponding signal estimation unit.

[0100] Based on this, although the back reflection signal changes the amplitude of the background signal (for example, when the back reflection signal adopts OOK modulation, the back reflection signal will change the amplitude of the background signal) or the phase (for example, when the back reflection signal adopts BPSK modulation, the back reflection signal will change the phase of the background signal), since the change of the background signal in one or more channel estimation units is constant, this change can be obtained through channel estimation, thereby eliminating the influence of the back reflection signal on the background signal. For example, taking a channel estimation unit including 4 OFDM symbols as an example, Figure 8 A schematic diagram of a back reflection signal and a background signal using an LTE-like pilot structure provided in another embodiment of the present application, comparing Figure 7 and Figure 8 , Figure 8 The back reflection signal and the background signal shown do not have the following relationship: the duration of a modulation symbol of the back reflection signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the signal estimation unit. Figure 8In the process, the energy of the first half of a channel estimation unit is reduced by reflection, while the energy of the second half is enhanced by reflection, which leads to a large deviation in channel estimation, and then causes the background signal to be received incorrectly, or even unable to be received. On the contrary, if Figure 7 As shown, the change of the back-reflection signal on the background signal is in units of the duration of the channel estimation unit. Therefore, although the back-reflection signal changes the amplitude or phase of the background signal, since the change of the background signal in one or more channel estimation units is constant, this change can be obtained through channel estimation, thereby eliminating the impact of the back-reflection signal on the normal transmission of the background signal.

[0101] Exemplarily, the above solution is described below by taking the first device as a tag, the second device as a base station, and the third device as a terminal device:

[0102] Fig. 9 A schematic diagram of an application scenario provided for another embodiment of the present application is as follows: Fig. 9 As shown, the tag 91 can obtain the background signal sent by the base station 92 to the terminal device 93, and the background signal carries the video, image or voice data sent by the base station 92 to the terminal device 93, or the tag 91 can obtain the background signal sent by the terminal device 93 to the base station 92, and the background signal carries the video, image or voice data sent by the terminal device 93 to the base station 92. The tag 91 uses the back reflection communication method to send the back reflection signal of the background signal to the base station 92 or the terminal device 93, and the back reflection signal can carry the data sent by the tag 91 to the base station 92 or the terminal device 93, and the data may include: information of the tag 91, etc. Among them, the duration of a modulation symbol of the back reflection signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the signal estimation unit. After the terminal device 93 receives the signal superimposed with the background signal and the back reflection signal, it first demodulates to obtain the background signal, and then uses the traditional method to parse the background signal to obtain the video, image or voice data sent by the base station 92 to the terminal device 93. Devices that need to receive the information of tag 91, such as other tags, can only parse the signal superimposed with the background signal and the back reflection signal to obtain the information of tag 91 without further parsing the information included in the background signal.

[0103] This embodiment provides that when the background signal is a signal using a WiFi-type pilot structure, and the background signal includes a constructed channel estimation unit, or when the background signal is a signal using an LTE-type pilot structure, and the background signal includes a channel estimation unit, in both cases, the duration of a modulation symbol of the back-reflection signal generated by the first device is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the signal estimation unit. Based on this, the change of the back-reflection signal to the background signal is in units of the duration of the channel estimation unit. Therefore, although the back-reflection signal changes the amplitude or phase of the background signal, since the change of the background signal in one or more channel estimation units is constant, this change can be obtained through channel estimation, thereby eliminating the influence of the back-reflection signal on the normal transmission of the background signal.

[0104] Fig.10 A flowchart of a back reflection communication method provided by another embodiment of the present application is shown in FIG. Fig.10 As shown, the method includes the following process:

[0105] Step S1001: a first device receives a background signal transmitted by a second device, where the background signal carries a back reflection signal sent to the first device.

[0106] Step S1002: The first device analyzes the back reflection signal, wherein the duration of a modulation symbol of the back reflection signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the signal estimation unit, and N is an integer greater than or equal to 1.

[0107] The similarities between this embodiment and the previous embodiment are that: the second device communicates with other devices using WiFi communication, in which case the background signal adopts a WiFi-like pilot structure. Optionally, the background signal using a WiFi-like pilot structure includes: a physical layer preamble and a data field, and the data field includes at least one signal estimation unit. The channel estimation unit includes a channel estimation field, and at least one data symbol adjacent to the channel estimation field. Alternatively, the second device communicates with other devices using LTE communication, in which case the background signal adopts an LTE-like pilot structure. The difference between this embodiment and the previous embodiment is that: this embodiment provides that the first device receives a back-reflected signal from the second device, that is, the first device acts as a receiving end of the back-reflected signal, while the previous embodiment provides that the first device sends a back-reflected signal using a back-reflected communication method, that is, the first device acts as a sending end of the back-reflected signal.

[0108] Optionally, since the background signal carries the back reflection signal sent to the first device, after the second device generates the background signal, the background signal is further modulated so that the background signal carries the back reflection signal, and the duration of the modulation symbol of the back reflection signal is N times the duration of the channel estimation unit of the background signal, and the modulation symbol is aligned with the time starting position of the signal estimation unit, and N is an integer greater than or equal to 1. Several implementation methods of the background signal and the back reflection signal can refer to the description of the aforementioned embodiments and will not be repeated here.

[0109] The data field of the background signal includes information to be sent by the second device to other devices. The back reflection signal carried by the background signal includes information to be sent by the second device to the first device. Optionally, the second device can determine whether it is necessary to add a padding portion after the data portion of the data field of the background signal based on the duration of the information to be sent to the first device. For example, if the second device determines that the information sent to the first device is longer and exceeds the duration of the data portion originally to be sent to other devices, the second device needs to add a padding portion after the data portion so that the duration of the data field of the background signal is sufficient to carry the information sent by the second device to the first device. Optionally, the physical layer preamble of the background signal also includes: a total length indication, a first length indication, or at least two of the second length indication. The meanings of the total length indication, the first length indication, and the second length indication have been introduced in the aforementioned embodiments and will not be repeated here.

[0110] After the first device receives the background signal carrying the back-reflected signal sent by the second device, it demodulates the background signal carrying the back-reflected signal using a method corresponding to the method used to modulate the background signal by the first device to obtain the information in the back-reflected signal. Other devices that receive the background signal carrying the back-reflected signal sent by the second device, after demodulating the background signal carrying the back-reflected signal using a method corresponding to the method used to modulate the background signal by the first device to obtain the background signal, need to further analyze the background signal to obtain the information sent by the second device to the device.

[0111] Fig.11 A schematic diagram of an application scenario provided for another embodiment of the present application is as follows: Fig.11As shown, the tag 111 can receive a background signal sent by the base station 112 to the terminal device 113, the background signal carries data such as video, image or voice sent by the base station 112 to the terminal device 113, and the background signal carries the back reflection signal sent by the base station 112 to the tag 111, or the tag 111 can receive a background signal sent by the terminal device 113 to the base station 112, the background signal carries data such as video, image or voice sent by the terminal device 113 to the base station 112, and the background signal carries the back reflection signal sent by the terminal device 113 to the tag 111. The tag 111 parses the back reflection signal to obtain information sent by the base station 112 or the terminal device 113 to the tag 111. Among them, the duration of a modulation symbol of the back reflection signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the signal estimation unit, and N is an integer greater than or equal to 1. After receiving the signal superimposed with the background signal and the back reflection signal, the terminal device 113 first demodulates to obtain the background signal, and then uses the traditional method to parse the background signal to obtain the video, image or voice data sent by the base station 112 to the terminal device 113. If the background signal adopts a structure that supports Wifi, the traditional method can be to parse the background signal using the Wifi protocol. If the background signal adopts a structure that supports LTE, the traditional method can be to parse the background signal using the LTE protocol. Devices that need to receive the information of the tag 111, such as other tags, can only parse the signal superimposed with the background signal and the back reflection signal to obtain the information of the tag 111, without further parsing the information included in the background signal.

[0112] For example, a channel estimation unit includes 4 OFDM symbols, such as Figure 7 As shown, the back reflection signal is a signal using OOK modulation or a signal using BPSK modulation. The amplitude of an OOK modulation symbol is A1 or A2, and the duration of the OOK modulation symbol is 1 times the duration of a channel estimation unit in the background signal, that is, the duration of the OOK modulation symbol is the same as the duration of a channel estimation unit, and each OOK modulation symbol is aligned with the time starting position of the corresponding signal estimation unit. Similarly, the phase of a BPSK modulation symbol is +1 or -1, and the duration of the BPSK modulation symbol is 1 times the duration of a channel estimation unit in the background signal, that is, the duration of the BPSK modulation symbol is the same as the duration of a channel estimation unit, and each BPSK modulation symbol is aligned with the time starting position of the corresponding signal estimation unit. Based on this, although the back reflection signal changes the amplitude or phase of the background signal, since the change of the background signal in one or more channel estimation units is constant, this change can be obtained through channel estimation, thereby eliminating the influence of the back reflection signal on the background signal.

[0113] Fig.12 A flowchart of a back reflection communication method provided in yet another embodiment of the present application is shown in FIG. Fig.12 As shown, the method includes the following process:

[0114] Step S1201: the first device generates a back reflection signal of a background signal, where the background signal is a signal transmitted by the second device.

[0115] Step S1202: The first device sends a back-reflected signal of a background signal by a back-reflected communication method, wherein the data symbol in the background signal includes a pilot subcarrier for estimating a phase deviation, the duration of a modulation symbol of the back-reflected signal is N times the duration of a data symbol, and the modulation symbol is aligned with the time start position of the data symbol, and N is an integer greater than or equal to 1.

[0116] Optionally, after the first device detects the background signal, it can modulate the information to be sent according to the duration of the channel estimation unit of the background signal to obtain a back reflection signal, so that the duration of a modulation symbol of the back reflection signal is N times the duration of a data symbol. The first device sends a back transmission signal so that the modulation symbol of the back reflection signal is aligned with the time starting position of the data symbol, and N is an integer greater than or equal to 1.

[0117] As described above, the second device can communicate with other devices using WiFi communication. This embodiment mainly introduces the back reflection communication method involved when the second device communicates with other devices using WiFi communication. The difference between this embodiment and the first embodiment is that in this embodiment, there is no need to construct a channel estimation unit, but the data symbol in the background signal includes a pilot subcarrier for estimating the phase deviation. The principle of estimating the phase deviation based on the pilot subcarrier is as follows:

[0118] The signal received on the pilot subcarrier can be expressed as: p =ph p e jφ e jθ , where p is the known pilot signal sent on the pilot subcarrier, θ is the phase deviation introduced by the back reflection signal on the background signal, φ is the phase deviation caused by other reasons besides the phase deviation introduced by the back reflection signal on the background signal, and h p is the channel on the pilot subcarrier, where h has been estimated by LTF p Therefore, we can get the phase deviation: jφ e jθ .

[0119] Similarly, the signal received on the data subcarrier can be expressed as: d =dhd e jφ e jθ , the estimated result of the transmitted signal d It can be obtained as follows:

[0120] It should be noted that, since the pilot subcarrier is only used to estimate the phase deviation, the back reflection signal should be a signal using a phase modulation method. Exemplarily, the phase modulation method may be a QPSK or BPSK modulation method.

[0121] When the second device communicates with other devices using WiFi communication, in this case, the background signal adopts a WiFi-like pilot structure. Optionally, the background signal using the WiFi-like pilot structure includes: a physical layer preamble and a data field, the data field includes at least one data symbol, and exemplarily, the data symbol is an OFDM symbol.

[0122] For example, Fig.13 A schematic diagram of a back reflection signal and a background signal using a WiFi-like pilot structure provided in an embodiment of the present application, such as Fig.13 As shown, the background signal includes: a physical layer preamble and a data field, and the data field includes at least one OFDM symbol. Exemplarily, the physical layer preamble includes: STF, LTF and SIG. Among them, STF is a sequence known to the transmitter and the receiver, and is used to synchronize the receiver with the transmitter. LTF is a sequence known to the transmitter and the receiver, and is used by the receiver to perform channel estimation on all data frames. SIG is a control signaling, which is used to indicate the modulation method, coding method and other information used by the data sent by the transmitter.

[0123] In the embodiment of the present application, the duration of a modulation symbol of the back reflection signal is N times the duration of a data symbol in the background signal, and the modulation symbol is aligned with the time start position of the data symbol, where N is an integer greater than or equal to 1, such as Fig.13 As shown, the phase of a BPSK modulation symbol is +1 or -1, the duration of the BPSK modulation symbol is the duration of several OFDM symbols in the background signal, and each BPSK modulation symbol is aligned with the time start position of the corresponding OFDM symbol.

[0124] Based on this, although the backreflection signal changes the phase of the background signal (for example, when the backreflection signal adopts QPSK or BPSK modulation, the backreflection signal will change the phase of the background signal), since the change of the background signal within one or more data symbols is constant, this change can be obtained through phase deviation estimation, thereby eliminating the influence of the backreflection signal on the background signal.

[0125] Optional, such as Fig.13 As shown, the data field of the background signal includes a data part, which includes: data sent by the second device. If the transmission duration of the data part is less than the transmission duration of the back reflection signal, the data field also includes a padding part. Assuming that the data field includes P data symbols, the first P1 of the P channel estimation units constitute the data part, and the last P2 constitute the padding part, P1+P2=P, P, P1 and P2 are all integers. Based on this, the physical layer preamble of the background signal also includes information for indicating the length of the data part and the length of the padding part. In one example, the information includes a first length indication and a second length indication, the first length indication is used to indicate the length of the data part, the second length indication is used to indicate the length of the padding part, and the sum of the length of the data part and the length of the padding part is the length of the data field. In another example, the information may include a total length indication and the first length indication, and the total length indication is used to indicate the total length of the data field. In another example, the information may include the total length indication and the second length indication. It should be noted that the "length" here can refer to the length of a byte or the duration. It can be understood that the sum of the length of the data part and the length of the padding part is the length of the data field, so the physical layer preamble can indicate any two of the lengths. In one example, any one length indication can be carried in the L-Length field of the physical layer preamble, and the other length indication can be carried in other fields of the physical layer preamble, such as a newly added field. Alternatively, both length indications are carried in the SIG field.

[0126] This embodiment provides that when the background signal is a signal using a WiFi-type pilot structure, and the data symbol in the background signal includes a pilot subcarrier for estimating the phase deviation, in this case, the duration of a modulation symbol of the backreflection signal generated by the first device is N times the duration of a data symbol in the background signal, and the modulation symbol is aligned with the time starting position of the data symbol. Based on this, the change of the backreflection signal to the background signal is in units of the duration of the data symbol. Therefore, although the backreflection signal changes the phase of the background signal, since the change of the background signal within one or more data symbols is constant, this change can be obtained through phase deviation estimation, thereby eliminating the influence of the backreflection signal on the background signal.

[0127] Fig.14 A flowchart of a back reflection communication method provided by another embodiment of the present application is shown in FIG. Fig.14 As shown, the method includes the following process:

[0128] Step S1401: a first device receives a background signal transmitted by a second device, where the background signal carries a back reflection signal sent to the first device.

[0129] Step S1402: The first device parses the back-reflected signal, wherein the data symbol in the background signal includes a pilot subcarrier for estimating the phase deviation, the duration of a modulation symbol of the back-reflected signal is N times the duration of a data symbol, and the modulation symbol is aligned with the time start position of the data symbol, and N is an integer greater than or equal to 1.

[0130] The similarity between this embodiment and the previous embodiment is that the second device communicates with other devices using a WiFi communication method, in which case the background signal uses a WiFi-like pilot structure. Optionally, the background signal using a WiFi-like pilot structure includes: a physical layer preamble and a data field, and the data field includes at least one data symbol. The difference between this embodiment and the previous embodiment is that this embodiment provides that the first device receives a back-reflected signal from the second device, that is, the first device acts as a receiving end of the back-reflected signal, while the previous embodiment provides that the first device sends a back-reflected signal using a back-reflected communication method, that is, the first device acts as a sending end of the back-reflected signal.

[0131] The same or similar contents between this embodiment and the previous embodiment are not described in detail here, and reference may be made to the previous embodiment.

[0132] Optionally, since the background signal carries the back reflection signal sent to the first device, after the second device generates the background signal, the background signal is further modulated so that the background signal carries the back reflection signal, and the data symbol in the background signal includes a pilot subcarrier for estimating the phase deviation, the duration of a modulation symbol of the back reflection signal is N times the duration of a data symbol, and the modulation symbol is aligned with the time start position of the data symbol, and N is an integer greater than or equal to 1. Several implementation methods of the background signal and the back reflection signal can be referred to the description of the aforementioned embodiment, which will not be repeated here.

[0133] The data field of the background signal includes information to be sent by the second device to other devices. The back reflection signal carried by the background signal includes information to be sent by the second device to the first device. Optionally, the second device can determine whether it is necessary to add a padding portion after the data portion of the data field of the background signal based on the duration of the information to be sent to the first device. For example, if the second device determines that the information sent to the first device is longer and exceeds the duration of the data portion originally to be sent to other devices, the second device needs to add a padding portion after the data portion so that the duration of the data field of the background signal is sufficient to carry the information sent by the second device to the first device. Optionally, the physical layer preamble of the background signal also includes: a total length indication, a first length indication, or at least two of the second length indication. The meanings of the total length indication, the first length indication, and the second length indication have been introduced in the aforementioned embodiments and will not be repeated here.

[0134] This embodiment provides that when the background signal is a signal using a WiFi-type pilot structure, and the background signal includes a pilot subcarrier for estimating a phase deviation, in this case, the duration of a modulation symbol of a back-reflected signal carried by the background signal is N times the duration of a data symbol in the background signal, and the modulation symbol is aligned with the time start position of the data symbol. Although the back-reflected signal changes the phase of the background signal, since the change of the background signal within one or more data symbols is constant, this change can be obtained through channel estimation, thereby eliminating the influence of the back-reflected signal on the normal transmission of the background signal.

[0135] The above-mentioned embodiments respectively provide a method for the first device to receive a back reflection signal or send a back reflection signal when the second device transmits a background signal via a WiFi communication method (including a case where a channel estimation unit needs to be constructed, and a case where a channel estimation unit does not need to be constructed) or via an LTE communication method. And the background signal and information carrying conditions of a WiFi-type pilot structure, as well as the background signal and information carrying conditions of an LTE-type pilot structure are provided. Among them, the process of the first device receiving a back reflection signal and sending a back reflection signal can be coupled. It should be noted that the back reflection signal received by the first device is different from the back reflection signal sent. The process of receiving a back reflection signal and sending a back reflection signal is described in combination below:

[0136] Fig.15 An interactive flow chart of a back reflection communication method provided by another embodiment of the present application is shown in FIG. Fig.15 As shown, the method includes the following process:

[0137] Step S1501: the second device sends a first background signal to the third device, where the first background signal carries a first back reflection signal.

[0138] If the second device sends the first background signal to the third device via WiFi communication, and the first background signal includes Figure 3 The channel estimation unit shown, or, if the second device sends the first background signal to the third device via LTE communication, the duration of a modulation symbol of the first back-reflected signal is N times the duration of a channel estimation unit in the first background signal, and the modulation symbol is aligned with the time starting position of the signal estimation unit, and N is an integer greater than or equal to 1.

[0139] If the second device sends the first background signal to the third device via WiFi communication, and the first background signal can be used as follows Fig.13 In the signal format shown, the duration of a modulation symbol of the first back-reflected signal is N times the duration of a data symbol in the first background signal, and the time starting positions of the modulation symbol and the data symbol are aligned, and N is an integer greater than or equal to 1.

[0140] Optionally, the first back-reflected signal carries information sent by the second device to the first device.

[0141] Optionally, the first background signal includes: data sent by the second device to the third device, and the data may be video data, image data, or voice data.

[0142] Optionally, the first background signal further includes: indication information, where the indication information is used to instruct the third device to send the second background signal at a specified time.

[0143] Step S1502: the first device sends a second back reflection signal of a second background signal to the second device by using a back reflection communication method. The second background signal is a background signal transmitted by the third device to the second device.

[0144] If the first background signal includes the indication information, the third device sends a second background signal at the specified time.

[0145] Optionally, the second background signal includes data sent by the third device to the second device. For example, if the first background signal includes request information sent by the second device to the third device, the second background signal may include response information sent by the third device to the second device.

[0146] If the third device sends the second background signal to the second device via WiFi communication, and the second background signal includes Figure 3 The channel estimation unit shown, or, if the third device sends the second background signal to the second device via LTE communication, the duration of a modulation symbol of the second back reflection signal is N times the duration of a channel estimation unit in the second background signal, and the modulation symbol is aligned with the time starting position of the signal estimation unit, and N is an integer greater than or equal to 1.

[0147] If the third device sends the second background signal to the second device via WiFi communication, and the second background signal is Fig.13 In the signal format shown, the duration of a modulation symbol of the second back-reflected signal is N times the duration of a data symbol in the second background signal, and the time starting positions of the modulation symbol and the data symbol are aligned, and N is an integer greater than or equal to 1.

[0148] Optionally, the second back-reflected signal includes: data sent by the first device to the second device, and the data may be, for example, request information.

[0149] Optionally, the method further includes:

[0150] Step S1503: The second device sends a response message to the first device.

[0151] If the second back-reflected signal includes: request information sent by the first device to the second device, the second device may send a response message to the first device.

[0152] It should be noted that, for the overlapping contents between this embodiment and the above embodiment, reference may be made to the above embodiment, which will not be described in detail.

[0153] Fig.16 A schematic diagram of a back reflection communication device 1600 provided in an embodiment of the present application, wherein the back reflection communication device is part or all of the first device described above, and the device has a back reflection communication function, such as Fig.16 As shown, the device 1600 includes:

[0154] The generating module 1601 is used to generate a back reflection signal of a background signal, where the background signal is a signal transmitted by the second device.

[0155] The sending module 1602 is used to send the back reflection signal of the background signal by adopting the back reflection communication mode.

[0156] The duration of a modulation symbol of the back reflection signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the signal estimation unit, and N is an integer greater than or equal to 1.

[0157] Fig.17 A schematic diagram of a back reflection communication device 1700 provided in an embodiment of the present application, wherein the back reflection communication device is part or all of the first device described above, such as Fig.17 As shown, the device 1700 includes:

[0158] The receiving module 1701 is used to receive a background signal transmitted by a second device, where the background signal carries a back-reflection signal sent to a back-reflection communication device.

[0159] The analysis module 1702 is used to analyze the back reflection signal.

[0160] The duration of a modulation symbol of the back reflection signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the signal estimation unit, and N is an integer greater than or equal to 1.

[0161] Optionally, the background signal includes: a physical layer preamble and a data field, the data field includes at least one signal estimation unit, the channel estimation unit includes a channel estimation field, and at least one data symbol adjacent to the channel estimation field.

[0162] Optionally, the data field includes a data part and a padding part, and the physical layer preamble of the background signal includes a first length indication and a second length indication, the first length indication is used to indicate the length of the data part, and the second length indication is used to indicate the length of the padding part.

[0163] Optionally, the modulation mode of the back reflection signal is QPSK, BPSK or OOK.

[0164] Optionally, the channel estimation unit includes multiple symbols, each symbol includes at least one pilot subcarrier, and the pilot subcarrier is used for channel estimation.

[0165] Optionally, the pilot subcarriers on multiple symbols are evenly distributed on the multiple symbols.

[0166] The back reflection communication device provided in the present application can be used to execute the corresponding back reflection communication method mentioned above. Its content and effect can be referred to the method embodiment part, which will not be described in detail.

[0167] Fig.18 A schematic diagram of a back reflection communication device 1800 provided in an embodiment of the present application, wherein the back reflection communication device is part or all of the first device described above, such as Fig.18 As shown, the device 1800 includes:

[0168] The generating module 1801 is configured to generate a back reflection signal of a background signal, where the background signal is a signal transmitted by a second device.

[0169] The sending module 1802 is used to send the back reflection signal of the background signal by adopting the back reflection communication mode.

[0170] The data symbol in the background signal includes a pilot subcarrier for estimating the phase deviation, the duration of a modulation symbol of the back-reflected signal is N times the duration of a data symbol, and the modulation symbol is aligned with the time starting position of the data symbol, and N is an integer greater than or equal to 1.

[0171] Fig.19 A schematic diagram of a back reflection communication device 1900 provided in an embodiment of the present application, wherein the back reflection communication device is part or all of the first device described above, such as Fig.19 As shown, the device 1900 includes:

[0172] The receiving module 1901 is configured to receive a background signal transmitted by a second device, where the background signal carries a back-reflection signal sent to the back-reflection communication device.

[0173] The analysis module 1902 is used to analyze the back reflection signal.

[0174] The data symbol in the background signal includes a pilot subcarrier for estimating the phase deviation, the duration of a modulation symbol of the back-reflected signal is N times the duration of a data symbol, and the modulation symbol is aligned with the time starting position of the data symbol, and N is an integer greater than or equal to 1.

[0175] Optionally, the background signal includes: a physical layer preamble and a data field, and the data field includes at least one data symbol.

[0176] Optionally, the data field includes a data part and a padding part, and the physical layer preamble of the background signal includes a first length indication and a second length indication, the first length indication is used to indicate the length of the data part, and the second length indication is used to indicate the length of the padding part.

[0177] Optionally, the back reflection signal is a signal using QPSK or BPSK modulation.

[0178] The back reflection communication device provided in the present application can be used to execute the corresponding back reflection communication method mentioned above. Its content and effect can be referred to the method embodiment part, which will not be described in detail.

[0179] Fig. 20 A schematic diagram of a back reflection communication device provided in an embodiment of the present application, wherein the back reflection communication device is the first device mentioned above, such as Fig. 20 As shown, the device includes: a memory 2001, a processor 2002 and a transceiver 2003, wherein the memory 2001 stores computer instructions, the transceiver 2003 is used for data transmission between other devices, and the processor 2002 is used for executing the computer instructions to implement part or all of the above-mentioned back reflection communication method.

[0180] The back-reflection communication device provided in the present application can be used to execute the corresponding back-reflection communication method mentioned above. Its content and effects can be referred to the method embodiment part, which will not be described in detail.

[0181] The embodiment of the present application also provides a communication device, which is applied to a second device and is used to execute the method or function of the second device in the above embodiment. In one example, the communication device includes: a generation module and a sending module, wherein the generation module is used to generate a background signal, and the background signal carries a back-transmitted signal sent to the first device; the sending module is used to send the back-reflected signal. Among them, the duration of a modulation symbol of the back-reflected signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the signal estimation unit, and N is an integer greater than or equal to 1. The channel estimation unit can refer to the above embodiment and will not be repeated here. Of course, the communication device can also be a chip in the second device, then the generation module can be a processing circuit in the chip, and the sending module can be an input and output interface of the chip, etc., wherein the communication device equipped with the chip can implement the method or function involved in the above second device.

[0182] The present application also provides a storage medium, including: a readable storage medium and computer instructions, wherein the computer instructions are stored in the readable storage medium; the computer instructions are used to implement part or all of the above-mentioned back reflection communication method.

[0183] An embodiment of the present application also provides a computer program product, which includes computer instructions, and the computer instructions are used to implement part or all of the above-mentioned back-reflection communication method.

[0184] The embodiment of the present application also provides a processor, which is used to implement the above method embodiment. The above processor can be a chip. Optionally, the components involved in the embodiment of the present application can be packaged on a chip, and can be executed by the processing circuit operation on the chip. Optionally, the functions performed by the components involved in the embodiment of the present application can be performed by a device including a chip or program that can execute the embodiment of the present application.

[0185] An embodiment of the present application also provides a chip, including: a processing circuit and an input-output circuit. A communication device equipped with the chip can implement the methods and functions involved in the above-mentioned first device.

[0186] The embodiment of the present application also provides a communication device, including a processor and a memory, wherein the processor is coupled to the memory, and the memory stores instructions, and when the processor executes the instructions, the communication device executes the method and function involved in the first device. Optionally, the memory can be a cache in the processor, or a storage module outside the processor.

[0187] The steps of the method or algorithm described in conjunction with the disclosure of the embodiments of the present application can be implemented in a hardware manner, or can be implemented by a processor executing a software instruction. The software instruction can be composed of corresponding software modules, and the software module can be stored in a random access memory (Random Access Memory, RAM), a flash memory, a read-only memory (Read Only Memory, ROM), an erasable programmable read-only memory (Erasable Programmable ROM, EPROM), an electrically erasable programmable read-only memory (Electrically EPROM, EEPROM), a register, a hard disk, a mobile hard disk, a read-only compact disk (CD-ROM) or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor so that the processor can read information from the storage medium and can write information to the storage medium. Of course, the storage medium can also be a component of the processor.

[0188] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A back reflection communication method, characterized in that: include: The first device generates a back reflection signal of a background signal, where the background signal is a signal transmitted by the second device; The first device sends the back reflection signal by using a back reflection communication method; Among them, the duration of a modulation symbol of the back-reflected signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the channel estimation unit, and N is an integer greater than or equal to 1; if the background signal is a signal using an LTE-type pilot structure, the channel estimation unit includes multiple symbols, each of which includes at least one pilot subcarrier, and the pilot subcarrier is used for channel estimation; if the background signal is a signal using a WiFi-type pilot structure, the channel estimation unit includes a channel estimation field, and at least one data symbol adjacent to the channel estimation field.

2. A back reflection communication method, characterized in that: include: The first device receives a background signal transmitted by the second device, where the background signal carries a back reflection signal sent to the first device; The first device analyzes the back reflection signal; Among them, the duration of a modulation symbol of the back-reflected signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the channel estimation unit, and N is an integer greater than or equal to 1; if the background signal is a signal using the channel LTE-type pilot structure, the channel estimation unit includes multiple symbols, each of which includes at least one pilot subcarrier, and the pilot subcarrier is used for channel estimation; if the background signal is a signal using a WiFi-type pilot structure, the channel estimation unit includes a channel estimation field, and at least one data symbol adjacent to the channel estimation field.

3. The method according to claim 1 or 2, characterized in that: If the background signal is a signal using a WiFi-type pilot structure, the background signal includes: a physical layer preamble and a data field, and the data field includes at least one of the channel estimation units.

4. The method according to claim 3, characterized in that: The data field includes a data part and a padding part, and the physical layer preamble of the background signal includes a first length indication and a second length indication, wherein the first length indication is used to indicate the length of the data part, and the second length indication is used to indicate the length of the padding part.

5. The method according to claim 1 or 2, characterized in that: The modulation mode of the back reflection signal is quadrature phase shift keying QPSK, binary phase shift keying BPSK or on-off keying OOK.

6. The method according to claim 1 or 2, characterized in that: The pilot subcarriers on the multiple symbols are evenly distributed on the multiple symbols.

7. A back reflection communication method, characterized in that: include: The first device generates a back reflection signal of a background signal, where the background signal is a signal transmitted by the second device; The first device sends the back reflection signal by using a back reflection communication method; Among them, the data symbol in the background signal includes a pilot subcarrier for estimating the phase deviation, the duration of a modulation symbol of the back-reflected signal is N times the duration of one of the data symbols, and the modulation symbol is aligned with the time starting position of the data symbol, and N is an integer greater than or equal to 1.

8. A back reflection communication method, characterized in that: include: The first device receives a background signal transmitted by the second device, where the background signal carries a back reflection signal sent to the first device; The first device analyzes the back reflection signal; Among them, the data symbol in the background signal includes a pilot subcarrier for estimating the phase deviation, the duration of a modulation symbol of the back-reflected signal is N times the duration of one of the data symbols, and the modulation symbol is aligned with the time starting position of the data symbol, and N is an integer greater than or equal to 1.

9. The method according to claim 7 or 8, characterized in that: The background signal includes: a physical layer preamble and a data field, and the data field includes at least one data symbol.

10. The method according to claim 9, characterized in that The data field includes a data part and a padding part, and the physical layer preamble of the background signal includes a first length indication and a second length indication, wherein the first length indication is used to indicate the length of the data part, and the second length indication is used to indicate the length of the padding part.

11. The method according to claim 7 or 8, characterized in that: The back reflection signal is a signal modulated by quadrature phase shift keying (QPSK) or binary phase shift keying (BPSK).

12. A back reflection communication device, characterized in that: include: A generating module, used for generating a back reflection signal of a background signal, wherein the background signal is a signal transmitted by the second device; A sending module, used for sending the back reflection signal by adopting a back reflection communication mode; Among them, the duration of a modulation symbol of the back-reflected signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the channel estimation unit, and N is an integer greater than or equal to 1; if the background signal is a signal using an LTE-type pilot structure, the channel estimation unit includes multiple symbols, each of which includes at least one pilot subcarrier, and the pilot subcarrier is used for channel estimation; if the background signal is a signal using a WiFi-type pilot structure, the channel estimation unit includes a channel estimation field, and at least one data symbol adjacent to the channel estimation field.

13. A back reflection communication device, characterized in that: include: A receiving module, used for receiving a background signal transmitted by a second device, wherein the background signal carries a back-reflected signal sent to the back-reflection communication device; An analysis module, used for analyzing the back reflection signal; Among them, the duration of a modulation symbol of the back-reflected signal is N times the duration of a channel estimation unit in the background signal, and the modulation symbol is aligned with the time start position of the channel estimation unit, and N is an integer greater than or equal to 1; if the background signal is a signal using an LTE-type pilot structure, the channel estimation unit includes multiple symbols, each of which includes at least one pilot subcarrier, and the pilot subcarrier is used for channel estimation; if the background signal is a signal using a WiFi-type pilot structure, the channel estimation unit includes a channel estimation field, and at least one data symbol adjacent to the channel estimation field.

14. The device according to claim 12 or 13, characterized in that If the background signal is a signal using a WiFi-type pilot structure, the background signal includes: a physical layer preamble and a data field, and the data field includes at least one of the channel estimation units.

15. The device according to claim 14, characterized in that The data field includes a data part and a padding part, and the physical layer preamble of the background signal includes a first length indication and a second length indication, wherein the first length indication is used to indicate the length of the data part, and the second length indication is used to indicate the length of the padding part.

16. The device according to claim 12 or 13, characterized in that The modulation mode of the back reflection signal is quadrature phase shift keying QPSK, binary phase shift keying BPSK or on-off keying OOK.

17. The device according to claim 12 or 13, characterized in that The pilot subcarriers on the multiple symbols are evenly distributed on the multiple symbols.

18. A back reflection communication device, characterized in that: include: A generating module, used for generating a back reflection signal of a background signal, wherein the background signal is a signal transmitted by the second device; A sending module, used for sending the back reflection signal by adopting a back reflection communication mode; Among them, the data symbol in the background signal includes a pilot subcarrier for estimating the phase deviation, the duration of a modulation symbol of the back-reflected signal is N times the duration of one of the data symbols, and the modulation symbol is aligned with the time starting position of the data symbol, and N is an integer greater than or equal to 1.

19. A back reflection communication device, characterized in that: include: A receiving module, used for receiving a background signal transmitted by a second device, wherein the background signal carries a back-reflected signal sent to the back-reflection communication device; An analysis module, used for analyzing the back reflection signal; Among them, the data symbol in the background signal includes a pilot subcarrier for estimating the phase deviation, the duration of a modulation symbol of the back-reflected signal is N times the duration of one of the data symbols, and the modulation symbol is aligned with the time starting position of the data symbol, and N is an integer greater than or equal to 1.

20. The device according to claim 18 or 19, characterized in that The background signal includes: a physical layer preamble and a data field, and the data field includes at least one data symbol.

21. The device according to claim 20, characterized in that The data field includes a data part and a padding part, and the physical layer preamble of the background signal includes a first length indication and a second length indication, wherein the first length indication is used to indicate the length of the data part, and the second length indication is used to indicate the length of the padding part.

22. The device according to claim 18 or 19, characterized in that The back reflection signal is a signal modulated by quadrature phase shift keying (QPSK) or binary phase shift keying (BPSK).

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