A distance measuring method and device

Abstract

The present application provides a method and apparatus for ranging, the method comprising: a first device sends a first signal on a first channel; the first device receives a second signal from a second device on a second channel, the second signal being a signal after the first signal is frequency-converted; the first device calculates the distance between the first device and the second device according to the phase difference between the carriers of the second signal. In the method provided by the present application, the first device calculates the distance between the first device and the second device according to the phase difference between the carriers of the received signal, which can improve the accuracy and efficiency of ranging. In addition, the first device and the second device can avoid interference between the transmitted and received signals by transmitting and receiving signals on different channels.

Description

Technical Field

[0001] The present application relates to the field of wireless communications, and in particular, to a distance measurement method and device. Background Art

[0002] An existing ranging method is to calculate the round-trip time (RTT) of the signal transmitted between the sender and the receiver through the interaction between the sender and the receiver, and then calculate the distance between the sender and the receiver based on the propagation speed of electromagnetic waves. However, due to the limitations of system bandwidth and indoor multipath environment, a small time error corresponds to a very large ranging error, so the measurement accuracy of this method is limited. Summary of the invention

[0003] The present application provides a distance measurement method, which can improve the distance measurement efficiency and distance measurement accuracy.

[0004] In a first aspect, a distance measurement method is provided, the method comprising: a first device sends a first signal on a first channel; the first device receives a second signal from a second device on a second channel, the second signal being a frequency-converted signal of the first signal; and the first device calculates the distance between the first device and the second device based on a phase difference between carrier waves of the second signal.

[0005] Based on the above technical solution, the first device calculates the distance between the first device and the second device by measuring the phase difference between the carriers of the second signal actively reflected by the second device, thereby achieving high-precision measurement of the distance between the devices. Even under multipath conditions, high measurement accuracy can be guaranteed. In addition, when using the method of the embodiment of the present application to measure the distance, there is no need for multiple interactions back and forth between the two user devices, which improves the efficiency of ranging. Transmitting the first signal and the second signal on different channels can also avoid interference between the signals, thereby ensuring high ranging accuracy.

[0006] In a second aspect, a ranging method is provided, the method comprising: a first device sends a first signal to a passive target on a first channel; the first device receives a second signal from a second device on a second channel, the second signal being a frequency-converted signal of the first signal; the first device calculates the sum of a distance from the passive target to the first device and a distance from the passive target to the second device based on a phase difference between carrier waves of the second signal; the first device determines a position of the passive target based on a sending direction of the first signal and the sum of the distances.

[0007] Based on the above technical solution, under the cooperation between two active devices, the first device can determine the position of the passive target according to the distance obtained by calculating the phase difference between the carriers of the second signal actively reflected by the second device and the direction in which the first device sends the first signal.

[0008] In combination with the first aspect or the second aspect, in some possible implementations, the method further includes: the first device sends a ranging request frame, where the ranging request frame includes information about the first channel and information about the second channel.

[0009] In combination with the first aspect or the second aspect, in some possible implementations, the method further includes: the first device receives a ranging request response frame from the second device, the ranging request response frame is sent by the second device according to the ranging request frame, the ranging request response frame includes available ranging time period information, and the available ranging time period information is used to indicate a first time period; and the first device sends a first signal on a first channel, including: in the first time period, the first device sends the first signal on the first channel.

[0010] In combination with the first aspect or the second aspect, in some possible implementations, the ranging request frame further carries at least one of the following information: ranging method information, and duration information of the first signal.

[0011] In combination with the first aspect or the second aspect, in some possible implementations, the information of the first channel includes at least one of the following information: the bandwidth of the first channel, the frequency of the first channel, and the channel number of the first channel; the information of the second channel includes at least one of the following information: the bandwidth of the second channel, the frequency of the second channel, and the channel number of the second channel.

[0012] In combination with the first aspect or the second aspect, in some possible implementations, the first signal includes at least one orthogonal frequency division multiplexing (OFDM) symbol, and the OFDM symbol does not include a guard interval.

[0013] Based on the above technical solution, the first device can avoid phase discontinuity between adjacent carriers of OFDM symbols and interference between different signals by sending OFDM symbols that do not include a guard interval for ranging, thereby ensuring high ranging accuracy.

[0014] In a third aspect, a ranging method is provided, the method comprising: a first device sends a first signal to a passive target on a first channel; the first device receives the first signal reflected by the passive target on the first channel; the first device calculates the distance between the first device and the passive target based on a phase difference between carrier waves of the first signal reflected by the passive target.

[0015] Based on the above technical solution, when there is only one active device, the distance between the first device and the passive target can also be calculated.

[0016] In a fourth aspect, a ranging method is provided, the method comprising: a second device receives a first signal on a first channel; the second device performs frequency conversion on the first signal to obtain a second signal; and the second device sends the second signal on a second channel.

[0017] Based on the above technical solution, the first device calculates the distance between the first device and the second device by measuring the phase difference between the carriers of the second signal actively reflected by the second device, thereby achieving high-precision measurement of the distance between the devices. Even under multipath conditions, high measurement accuracy can be guaranteed. In addition, when using the method of the embodiment of the present application to measure the distance, there is no need for multiple interactions back and forth between the two user devices, which improves the efficiency of ranging. Transmitting the first signal and the second signal on different channels can also avoid interference between the signals, thereby ensuring high ranging accuracy.

[0018] In combination with the fourth aspect, in some possible implementations, the method further includes: the second device receiving a ranging request frame from the first device, the ranging request frame including information indicating the first channel and information indicating the second channel.

[0019] In combination with the fourth aspect, in some possible implementations, the method also includes: the second device sends a ranging request response frame according to the ranging request frame, the ranging request response frame includes available ranging time period information, and the available ranging time period information is used to indicate a first time period; and the second device receives a first signal on a first channel, including: in the first time period, the second device receives the first signal on the first channel.

[0020] In combination with the fourth aspect, in some possible implementations, the ranging request frame further carries at least one of the following information: ranging method information, and duration information of the first signal.

[0021] In combination with the fourth aspect, in some possible implementations, the information of the first channel includes at least one of the following information: the bandwidth of the first channel, the frequency of the first channel, and the channel number of the first channel; the information of the second channel includes at least one of the following information: the bandwidth of the second channel, the frequency of the second channel, and the channel number of the second channel.

[0022] In combination with the fourth aspect, in some possible implementations, the first signal includes at least one OFDM symbol, and the OFDM symbol does not include a guard interval.

[0023] Based on the above technical solution, the first device can avoid phase discontinuity between adjacent carriers of OFDM symbols and interference between different signals by sending OFDM symbols that do not include a guard interval for ranging, thereby ensuring high ranging accuracy.

[0024] In a fifth aspect, a ranging device is provided, comprising a transceiver unit and a processing unit: the transceiver unit is used to send a first signal on a first channel; the transceiver unit is also used to receive a second signal from a second device on a second channel, the second signal being a frequency-converted signal of the first signal; the processing unit is used to calculate the distance between the device and the second device based on the phase difference between the carrier waves of the second signal.

[0025] In a sixth aspect, a ranging device is provided, comprising a transceiver unit and a processing unit: the transceiver unit is used to send a first signal to a passive target on a first channel; the transceiver unit is also used to receive a second signal from a second device on a second channel, the second signal being a frequency-converted signal of the first signal; the processing unit is used to calculate the sum of the distance from the passive target to the device and the distance to the second device based on a phase difference between carrier waves of the second signal; the processing unit is also used to determine the position of the passive target based on the sending direction of the first signal and the sum of the distances.

[0026] In combination with the fifth aspect or the sixth aspect, in some possible implementations, the transceiver unit is further used to: send a ranging request frame, where the ranging request frame includes information about the first channel and information about the second channel.

[0027] In combination with the fifth aspect or the sixth aspect, in some possible implementations, the transceiver unit is further used to: receive a ranging request response frame from the second device, the ranging request response frame is sent by the second device according to the ranging request frame, the ranging request response frame includes available ranging time period information, and the available ranging time period information is used to indicate a first time period; and the transceiver unit is specifically used to: send the first signal on the first channel during the first time period.

[0028] In combination with the fifth aspect or the sixth aspect, in some possible implementations, the ranging request frame further carries at least one of the following information: ranging method information, and duration information of the first signal.

[0029] In combination with the fifth aspect or the sixth aspect, in some possible implementations, the information of the first channel includes at least one of the following information: the bandwidth of the first channel, the frequency of the first channel, and the channel number of the first channel; the information of the second channel includes at least one of the following information: the bandwidth of the second channel, the frequency of the second channel, and the channel number of the second channel.

[0030] In combination with the fifth aspect or the sixth aspect, in some possible implementations, the first signal includes at least one OFDM symbol, and the OFDM symbol does not include a guard interval.

[0031] In the seventh aspect, a ranging device is provided, comprising: a transceiver unit and a processing unit: the transceiver unit is used to send a first signal to a passive target on the first channel; the transceiver unit is also used to receive a first signal reflected by the passive target on the first channel; the processing unit is used to calculate the distance between the device and the passive target based on the phase difference between the carriers of the first signal reflected by the passive target.

[0032] In an eighth aspect, a ranging device is provided, comprising a transceiver unit and a processing unit: the transceiver unit is used to receive a first signal on a first channel; the processing unit is used to convert the frequency of the first signal to obtain a second signal; the transceiver unit is also used to send the second signal on a second channel.

[0033] In combination with the eighth aspect, in some possible implementations, the transceiver unit is further used to: receive a ranging request frame from the first device, where the ranging request frame includes information about the first channel and information about the second channel.

[0034] In combination with the eighth aspect, in some possible implementations, the transceiver unit is further used to: send a ranging request response frame according to the ranging request frame, the ranging request response frame including available ranging time period information, the available ranging time period information being used to indicate a first time period; and the transceiver unit is specifically used to: receive the first signal on the first channel during the first time period.

[0035] In combination with the eighth aspect, in some possible implementations, the ranging request frame also carries at least one of the following information: ranging method information, and duration information of the first signal.

[0036] In combination with the eighth aspect, in some possible implementations, the information of the first channel includes at least one of the following information: the bandwidth of the first channel, the frequency of the first channel, and the channel number of the first channel; the information of the second channel includes at least one of the following information: the bandwidth of the second channel, the frequency of the second channel, and the channel number of the second channel.

[0037] In combination with the eighth aspect, in some possible implementations, the first signal includes at least one OFDM symbol, and the OFDM symbol does not include a guard interval.

[0038] In a ninth aspect, a distance measuring device is provided, comprising a processor. The processor is coupled to a memory and can be used to execute instructions in the memory to implement the method in any possible implementation of the first to fourth aspects. Optionally, the distance measuring device also includes a memory. Optionally, the distance measuring device also includes a communication interface, and the processor is coupled to the communication interface.

[0039] In one implementation, the distance measuring device is a communication device, such as the first device and the second device in the embodiment of the present application. When the distance measuring device is a communication device, the communication interface may be a transceiver, or an input / output interface.

[0040] In another implementation, the distance measuring device is a chip configured in a communication device, such as a chip configured in the first device and the second device in the embodiment of the present application. When the distance measuring device is a chip configured in a communication device, the communication interface may be an input / output interface.

[0041] Optionally, the transceiver may be a transceiver circuit. Optionally, the input / output interface may be an input / output circuit.

[0042] In a tenth aspect, a processor is provided, comprising: an input circuit, an output circuit, and a processing circuit. The processing circuit is used to receive a signal through the input circuit and transmit a signal through the output circuit, so that the processor executes the method in any possible implementation of the first to fourth aspects above.

[0043] In the specific implementation process, the processor can be a chip, the input circuit can be an input pin, the output circuit can be an output pin, and the processing circuit can be a transistor, a gate circuit, a trigger, and various logic circuits. The input signal received by the input circuit can be, for example, but not limited to, received and input by a receiver, and the signal output by the output circuit can be, for example, but not limited to, output to a transmitter and transmitted by the transmitter, and the input circuit and the output circuit can be the same circuit, which is used as an input circuit and an output circuit at different times. The embodiments of the present application do not limit the specific implementation methods of the processor and various circuits.

[0044] In an eleventh aspect, a processing device is provided, comprising a processor and a memory. The processor is used to read instructions stored in the memory, and can receive signals through a receiver and transmit signals through a transmitter to execute the method in any possible implementation of the first to fourth aspects above.

[0045] Optionally, the number of the processors is one or more, and the number of the memories is one or more.

[0046] Optionally, the memory may be integrated with the processor, or the memory may be provided separately from the processor.

[0047] In the specific implementation process, the memory can be a non-transitory memory, such as a read-only memory (ROM), which can be integrated with the processor on the same chip or can be set on different chips respectively. The embodiments of the present application do not limit the type of memory and the setting method of the memory and the processor.

[0048] It should be understood that the relevant data interaction process, such as sending indication information, can be a process of outputting indication information from a processor, and receiving capability information can be a process of receiving input capability information from a processor. Specifically, the processed output data can be output to a transmitter, and the input data received by the processor can come from a receiver. Among them, the transmitter and the receiver can be collectively referred to as a transceiver.

[0049] The processing device in the above-mentioned eleventh aspect can be a chip. The processor can be implemented by hardware or by software. When implemented by hardware, the processor can be a logic circuit, an integrated circuit, etc.; when implemented by software, the processor can be a general-purpose processor, which is implemented by reading the software code stored in the memory. The memory can be integrated in the processor or can be located outside the processor and exist independently.

[0050] In the twelfth aspect, a computer program product is provided, which includes: a computer program (also referred to as code, or instruction), which, when executed, enables a computer to execute a method in any possible implementation of the first to fourth aspects above.

[0051] In the thirteenth aspect, a computer-readable medium is provided, which stores a computer program (also referred to as code, or instruction) which, when executed on a computer, enables the computer to execute a method in any possible implementation of the first to fourth aspects above.

[0052] In a fourteenth aspect, a communication system is provided, comprising the aforementioned first device and second device. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic diagram of an application scenario of the method provided in an embodiment of the present application.

[0054] Figure 2 It is a schematic diagram of the FTM method in TB mode.

[0055] Figure 3 It is a schematic diagram of the FTM method in TB mode.

[0056] Figure 4 It is a schematic diagram of the FTM method in Non-TB mode.

[0057] Figure 5 It is the principle diagram of the FTM method in TB mode.

[0058] Figure 6 It is the principle diagram of the FTM method in Non-TB mode.

[0059] Figure 7 is a schematic diagram of the radar system.

[0060] Figure 8 It is a schematic flowchart of the ranging method provided in an embodiment of the present application.

[0061] Fig. 9 This is the processing flow of the ranging signal.

[0062] Fig.10 Graph showing the relationship between the amplitude and phase of CSI and the subcarrier frequency without multipath.

[0063] Fig.11 It is a diagram showing the relationship between the amplitude and phase of CSI and the subcarrier frequency under multipath conditions.

[0064] Fig.12 It is a schematic flowchart of the ranging method provided in an embodiment of the present application.

[0065] Fig.13 It is a schematic diagram of the distance measurement method provided in an embodiment of the present application.

[0066] Fig.14 It is a schematic flowchart of the ranging method provided in an embodiment of the present application.

[0067] Fig.15 It is a schematic block diagram of a distance measuring device provided in an embodiment of the present application.

[0068] Fig.16 It is a schematic block diagram of a distance measuring device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0069] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0070] The technical solution of the embodiments of the present application can be applied to a wireless local area network (WLAN), and the embodiments of the present application can also be applied to any one of the IEEE 802.11 series protocols currently adopted by the WLAN, for example, it can be applied to a communication system of the IEEE 802.11az protocol currently supported by the WLAN, or to a communication system supporting the next-generation protocol of 802.11az, or to a communication system supporting 802.11be, or to a wireless fidelity sensing communication system, or other scenarios requiring positioning or ranging.

[0071] The method provided in the embodiment of the present application can be applied to the scenarios of locating active targets and locating passive targets. For example, Figure 1 A schematic diagram shows a scenario in which the method provided in an embodiment of the present application is applied to positioning an active target.

[0072] like Figure 1 As shown, both the first device 110 and the second device 120 support multi-connection features, that is, the first device 110 and the second device 120 can work on different channels at the same time. In the case where the first device 110 has a ranging requirement, that is, the second device 120 needs to be located, the first device 110 can send a ranging request frame to the second device 120, and negotiate the ranging method used by the first device 110 and the second device 120 for ranging, the information of the channel for signal transmission, the bandwidth of the channel, and the signal duration, etc. Correspondingly, the second device 120 can also reply to the first device 110 with information agreeing to assist the first device 110 in ranging. Similarly, in the case where the second device has a ranging requirement, that is, the first device 110 needs to be located, the second device 120 can send a ranging request frame to the first device 110, and negotiate the ranging method used by the first device 110 and the second device 120 for ranging, the information of the channel for signal transmission, the bandwidth of the channel, and the signal duration, etc. Correspondingly, the first device 110 may reply to the second device 120 with information indicating that it agrees to assist the second device 120 in ranging.

[0073] Among them, the first device can be a wireless fidelity (WiFi) device, a router, a terminal device, and a user station (STA). The second device can also be a WiFi device, a router, a terminal device, and a STA. For example, taking WLAN as an example, the first device in the embodiment of the present application can be a STA, and the second device can also be a STA. Specifically, if the first device initiates a ranging request, the first device can be an initiator station (ISTA), and the second device can be a responder station (RSTA); if the second device initiates a ranging request, the second device can be an ISTA, and the first device can be an RSTA.

[0074] At present, a location measurement method called fine time measurement (FTM) is defined in the WiFi standard, and the latest corresponding standard is IEEE 801.11az. The FTM method calculates the RTT of the signal transmission between the two devices through the interaction between ISTA and RSTA, and then calculates the distance of signal propagation between ISTA and RSTA based on the propagation speed of electromagnetic waves. When there is a line of sight (LOS) between the initiator ISTA and RATA, the signal propagation distance is the distance between ISTA and RSTA. When there is no line of sight (NLOS) between ISTA and RSTA, the FTM method will not work.

[0075] like Figure 2 As shown, the FTM method mainly includes three processes, namely the negotiation process, the measurement process and the result feedback process. When ISTA has an FTM measurement requirement, it can send an FTM request frame to RSTA. After receiving the FTM request frame, RSTA will send information about the available time period to ISTA. At the same time, during the negotiation process, ISTA and RSTA will also exchange the capabilities of both parties, and RSTA can also assign a ranging identifier (ranging identifier, ranging ID) to ISTA. When ISTA and RSTA are associated, RSTA does not need to assign a ranging identifier to ISTA. ISTA can directly use the associated identifier (associated identifier, associated ID) between RSTA and ISTA. After the negotiation process is completed, multiple measurement processes and result feedback processes can be performed between ISTA and RSTA without the need for further negotiation. As Figure 2As shown, in the negotiation process, ISTA can obtain the available time period information of RSTA. In the available time period N, ISTA and RSTA can perform a measurement process and result feedback process. In the available time period N+1, ISTA and RSTA can perform another measurement process and result feedback process. The duration of each available time period is equal.

[0076] The detailed interaction process of the FTM protocol in the trigger-based (TB) mode for measurement and result feedback is as follows: Figure 3 As shown in Figure 2, the measurement and result feedback process in the non-trigger-based (Non-TB) mode is as follows: Figure 4 As shown. Figure 3 As shown, in TB mode, RSTA sends a polling frame to ISTA in its idle time window. The purpose of the polling frame is to notify ISTA that it can start measuring. After receiving the polling frame, ISTA occupies the channel by sending a clear to send (CTS) frame to ISTA. After receiving the CTS frame, RSTA sends a scheduling frame for distance measurement to ISTA. After receiving the scheduling frame, ISTA replies with a null data packet (NDP) frame to RSTA. After receiving the NDP, RSTA sends a null data packet announcement (NDPA) frame for ranging to ISTA. After the minimum interframe space (SIFS) time, RSTA sends another NDP frame to ISTA. After the SIFS time, RSTA feeds back a location measurement report (LMR) to ISTA. Among them, the time interval for each interaction between ISTA and RSTA is SIFS time. As shown Figure 4 As shown in the figure, in the Non-TB mode, in the measurement process, ISTA will first send an NDPA frame to RSTA, and after SIFS time, ISTA will send an uplink (UL) NDP frame to RSTA; after receiving the NDP frame, RSTA will reply a downlink (DL) NDP frame to ISTA after SIFS time; after another SIFS time, RSTA will send LMR to ISTA.

[0077] The basic principle of FTM distance measurement is as follows Figure 5 and Figure 6As shown in the figure, the principle of FTM ranging is basically the same in both TB mode and Non-TB mode, so here we only take TB mode as an example for explanation. When performing FTM ranging, both ISTA and RSTA need to record the sending and receiving time of all NDP frames during the measurement. Figure 5 As shown in the figure, when ISTA sends an UL NDP frame, ISTA records the sending time t1 of the frame, and after RSTA receives the frame, it records the receiving time t2 of the frame; when RSTA sends a DL NDP, it needs to record the corresponding sending time t3, and after ISTA receives the DL NDP frame, it records the corresponding receiving time t4. The round-trip time RTT of the signal propagation between ISTA and RSTA is:

[0078] RTT = [(t4-t1)-(t3-t2)] (1)

[0079] Combined with the propagation speed of electromagnetic waves, the distance D between ISTA and RSTA can be obtained as:

[0080]

[0081] Where c is the speed of light.

[0082] ISTA combines the FTM measurement results between it and multiple RSTAs, and ISTA can also infer its location information.

[0083] The currently known distance measurement method also includes radar technology. Figure 7 As shown, the basic technical principle of radar is that the radar transmitting system 710 sends out a specific electromagnetic wave signal, which will be reflected when encountering the target obstacle 720 during the propagation process. The radar system receives the reflected signal, compares it with the transmitted signal, and calculates the target's distance, speed, direction and other information, and can even form an image.

[0084] As mentioned above, the FTM method measures distance by measuring the propagation time of the signal between ISTA and RSTA. However, due to the limitations of system bandwidth and indoor multipath environment, the accuracy of signal propagation time measurement is limited, and a very small time error corresponds to a very large distance measurement error. For example, a time error of 10ns corresponds to a distance error of 3m. Therefore, the accuracy of the FTM method in measuring distance is not very high. In addition, the FTM method requires multiple interactions between ISTA and RSTA to complete the measurement. Therefore, the measurement process is cumbersome and the measurement efficiency is low.

[0085] Therefore, the present application provides a distance measurement method to improve the accuracy and efficiency of measuring the distance between two devices.

[0086] The method provided by the embodiment of the present application will be described in detail below in conjunction with the accompanying drawings. For ease of description, the embodiment shown below is described by taking the first device and the second device as STA as an example, but this should not be a limitation to the present application. The first device and the second device may also be WiFi devices, routers, and terminal devices, and the first device and the second device may be the same device or different types of devices.

[0087] Figure 8 A schematic flowchart of a distance measurement method provided in an embodiment of the present application is shown. Figure 8 The method 800 shown may be performed by Figure 1 The first device 110 and the second device 120 shown in FIG. Figure 8 As shown, method 800 includes S810-S850, and each step is described in detail below.

[0088] S810, STA#1 (an example of the first device) sends a first signal to STA#2 (an example of the second device).

[0089] STA#1 sends a first signal on a first channel.

[0090] It should be understood that since STA#1 does not know the location of STA#2, STA#1 can send the first signal in a broadcasting manner.

[0091] The first signal may include a first carrier and a second carrier. The first channel may include the first carrier and the second carrier, and it can also be understood that the frequency of the first carrier and the frequency of the second carrier are determined according to information of the first channel. The first channel is a channel for transmitting the first signal.

[0092] It should be noted that the embodiment of the present application does not limit the form of the first signal. For example, the first signal may be an OFDM symbol that does not include a guard interval, or the first signal may be other multi-carrier signals.

[0093] For ease of understanding, the embodiment of the present application is described by taking the first signal being a first OFDM signal as an example.

[0094] STA#1 sends a first OFDM signal in a broadcasting manner through a first channel. The first OFDM signal is obtained by directly connecting a long training field (LTF) symbol that does not include a guard interval and is repeated multiple times. Therefore, during the transmission time of the first OFDM signal, each subcarrier of the first OFDM signal is a continuous single tone signal. The first OFDM signal S T (t) can be expressed as:

[0095]

[0096] Wherein, X(k) is the LTF sequence, N is the number of LTF sequences, and T is the time length of the first OFDM signal.

[0097] Optionally, if the method 800 executes S850, STA#1 sends a first OFDM signal in a broadcasting manner through a first channel in a first time period.

[0098] Optionally, the first OFDM signal sent by STA#1 may use only some subcarriers, for example, only one subcarrier out of every four subcarriers is used (for example, using a 1×LTF sequence); or one subcarrier out of every two subcarriers is used (for example, using a 2×LTF sequence).

[0099] S820, STA#2 sends a second signal.

[0100] In one implementation, after STA#2 receives the first signal from STA#1, it changes the center frequency of the first signal through a mixer to generate a second signal. Wherein, the first signal may include a first carrier and a second carrier, and the second signal may include a third carrier and a fourth carrier. The second channel may include the third carrier and the fourth carrier. STA#2 changing the center frequency of the first signal can also be understood as STA#2 changing the frequencies of the first carrier and the second carrier to generate the third carrier and the fourth carrier. It can be understood that the frequency of the third carrier and the frequency of the fourth carrier are determined based on the information of the second channel. Wherein, the second channel is used to transmit the second signal.

[0101] In another implementation, after STA#2 receives the first signal from STA#1, it changes the center frequency of the first signal through a mixer and amplifies the power of the first signal through a power amplifier to generate a second signal. Wherein, the first signal may include a first carrier and a second carrier, the second signal may include a third carrier and a fourth carrier, and the second channel may include the third carrier and the fourth carrier. STA#2 changing the center frequency of the first signal can also be understood as STA#2 changing the frequencies of the first carrier and the second carrier to generate the third carrier and the fourth carrier. It can be understood that the frequency of the third carrier and the frequency of the fourth carrier are determined according to the information of the second channel. Wherein, the second channel is used to transmit the second signal. The change in the power of the second signal relative to the power of the first signal is also determined according to the information of the second channel.

[0102] Then, STA#2 sends a second signal on the second channel.

[0103] It should be understood that since STA#2 does not know the location of STA#1, STA#2 can send the second signal in a broadcasting manner.

[0104] Taking the first signal sent by STA#1 as the first OFDM signal, STA#2 converts the first OFDM signal into a second OFDM signal S R (t) can be expressed as:

[0105]

[0106] Where d is the distance between STA#1 and STA#2, c is the speed of light, It is due to the phase shift introduced by multiple frequency conversions.

[0107] like Fig. 9 As shown, the initial sampling signal is The first signal obtained by STA#1 after frequency conversion of the sampled signal according to the information of the first channel is Then, STA#2 converts the first information according to the information of the second channel to obtain the second signal: Then, STA#1 converts the received second signal according to the processing capability of the baseband to obtain the signal: Therefore, it can be seen that in the ranging process, the phase offset introduced for

[0108] S830, STA#1 calculates the distance between itself and STA#2.

[0109] STA#1 calculates the distance between STA#1 and STA#2 based on the phase difference between the carriers of the second signal. For example, STA#1 may calculate the distance between STA#1 and STA#2 based on the phase difference between the third carrier and the fourth carrier in the second signal.

[0110] For example, the first signal is a first OFDM signal. Correspondingly, the second signal received by STA#1 is a second OFDM signal.

[0111] According to formula (4), the phase P(k) of the channel state information of the kth subcarrier in the second OFDM signal received by STA#1 can be expressed as:

[0112]

[0113] Therefore, the phase difference of the channel state information of two adjacent subcarriers is It can be expressed as:

[0114]

[0115] Therefore, the distance d between STA#1 and STA#2 can be expressed as:

[0116]

[0117] Wherein, Δf is the frequency interval between two adjacent subcarriers.

[0118] Optionally, before S810, STA#1 and STA#2 may interact to negotiate information about the first channel and information about the second channel used for subsequent ranging; or, STA#1 may send information about the first channel and information about the second channel used for subsequent ranging in a broadcast manner; or, STA#2 may send information about the first channel and information about the second channel used for subsequent ranging in a broadcast manner.

[0119] Taking the interaction between STA#1 and STA#2 to negotiate the information of the first channel and the information of the second channel as an example, the method 800 may also include S840-S850.

[0120] S840, STA#1 sends a ranging request frame.

[0121] It should be understood that since STA#1 does not know the location of STA#2, STA#1 may send the ranging request frame in a broadcast manner.

[0122] The ranging request frame may include information of the first channel and information of the second channel. The information of the first channel may include at least one of the following information: bandwidth of the first channel, frequency of the first channel, and channel number of the first channel; the information of the second channel may include at least one of the following information: bandwidth of the second channel, frequency of the second channel, and channel number of the second channel.

[0123] Optionally, the ranging request frame may also carry at least one of the following information: ranging method information and duration information of the first signal.

[0124] S850, STA#2 sends a ranging request response frame.

[0125] After STA#2 receives the ranging request frame from STA#1, STA#2 may reply a ranging request response frame to STA#1.

[0126] It should be understood that since STA#2 does not know the location of STA#1, STA#2 may send the ranging request response frame in a broadcast manner.

[0127] That is, if STA#2 can support the ranging request of STA#1, it replies a ranging request response frame to STA#1. The ranging request response frame may include available ranging time period information, and the available ranging time period information is used to indicate the first time period.

[0128] Optionally, after receiving the ranging request frame from STA#1, STA#2 can first send an acknowledgment (ACK) frame to STA#1 after SIFS time. Then, STA#2 parses the information carried in the ranging request frame, and if STA#2 can support the ranging request from STA#1, it replies with a ranging request response frame to STA#1.

[0129] Optionally, after STA#1 receives the ranging request response frame from STA#2, it may also send an ACK frame to STA#2 after a SIFS time.

[0130] S840-S850 only illustrates the process of negotiating the information of the first channel and the information of the second channel by taking the interaction between STA#1 and STA#2 as an example, but this should not constitute a limitation to the present application.

[0131] Fig.10 and Fig.11 The simulation results of the amplitude and phase of the channel state information (CSI) measured under the conditions of no multipath and multipath and the relationship between the frequency are shown respectively. Fig.10 (b) and Fig.11 As shown in (b), whether there is no multipath or there is multipath, the phase of CSI and the frequency of the carrier are approximately linearly related, and the slope of this linear relationship determines the ranging result. It can be seen that the distance between two devices calculated based on the phase difference between different carriers will not be limited by the indoor multipath environment. Fig.10 As shown in (a), in the absence of multipath conditions, the amplitude of CSI basically does not change with the frequency of the carrier, such as Fig.11 As shown in (a), under multipath conditions, the amplitude of CSI changes significantly with the change of carrier frequency. Therefore, it can be seen that under multipath conditions, calculating the distance between two devices by measuring the transmission time of the signal will produce a large error.

[0132] Therefore, in an embodiment of the present application, STA#1 calculates the distance between itself and STA#2 by measuring the phase difference between the carriers of the second signal actively reflected by STA#2, thereby achieving high-precision measurement of the distance between devices. Even under multipath conditions, high measurement accuracy can be guaranteed. In addition, when using the method of an embodiment of the present application to measure distance, there is no need for multiple interactions between the two user devices, which improves the efficiency of ranging. Transmitting the first signal and the second signal on different channels can also avoid interference between the signals, thereby ensuring high ranging accuracy.

[0133] In addition, since the first signal sent by STA#1 may use only part of the carrier, the transmission power of the used carrier may be increased while keeping the total transmission power unchanged, thereby extending the maximum ranging range.

[0134] Fig.12 A schematic flow chart of a distance measurement method provided in another embodiment of the present application is shown. Fig.12 The method 1200 shown may be performed by Figure 1 The first device 110 and the second device 120 are shown to execute the method 1200. The method 1200 includes S1210-S1250, wherein S1240-S1250 and S1220 are the same as S840-S850 and S820 in the method 800, and are not described here for brevity.

[0135] S1210, STA#1 (an example of the first device) sends a first signal to a passive target, and then the passive target reflects the first signal to STA#2 (an example of the second device).

[0136] It should be understood that STA#1 does not know the specific direction of the passive target, so STA#1 sends the first signal in different directions in turn.

[0137] Taking the first signal as the first OFDM signal as an example, as described above, STA#1 sends the first OFDM signal to the passive target on the first channel. The first OFDM signal S T (t) can be expressed as:

[0138]

[0139] S1230, STA#1 determines the location of the passive target.

[0140] As mentioned above, STA#1 sends the first signal in different directions in sequence. If STA#1 sends the first signal in a certain direction and receives the second signal reflected by the passive target to STA#2 and then sent back after being processed by STA#2, STA#1 can determine the direction of the passive target relative to STA#1.

[0141] Further, STA# calculates the sum of the distance from the passive target to STA#1 and the distance to STA#2 based on the phase difference between the two carriers of the second signal.

[0142] Taking the first signal as the first OFDM signal as an example, as described above, STA#2 converts the first OFDM signal into a second OFDM signal S R (t) can be expressed as:

[0143]

[0144] Where D is the distance of signal propagation. It can be seen that in the process of ranging, the distance of signal propagation is the sum of the distance from the passive target to STA#1, the distance from the passive target to STA#2, and the distance from STA#1 to STA#2. The distance d from STA#1 to STA#2 can be measured using method 800.

[0145] Therefore, the sum of the distance from the passive target to STA#1 and the distance from the passive target to STA#2 can be calculated as: Dd.

[0146] like Fig.13 As shown, assuming that the position of STA#1 is represented by (x 1 ,y 1 ), the position of STA#2 is represented by (x 2 ,y 2 ), then we can know that the passive target is in (x 1 ,y 1 ) and (x 2 ,y 2 ) as the focus and Dd as the major axis diameter. 1 ,y 1 ) as the endpoint and draw a ray in the direction in which STA#1 sends the first OFDM signal. The intersection of the ray and the ellipse is the specific position of the passive target.

[0147] In an embodiment of the present application, under the cooperation between two active devices, STA#1 can determine the position of the passive target based on the distance obtained by calculating the phase difference between the two carriers of the second signal actively reflected by STA#2, and the direction in which STA#1 sends the first signal.

[0148] Fig.14 A schematic flow chart of a distance measurement method provided by yet another embodiment of the present application is shown. Fig.14 The method 1400 shown may be performed by Figure 1 The method 1400 is performed by the first device 110 or the second device 120. The method 1400 includes S1410-S1430, and each step is described in detail below.

[0149] S1410, STA#1 sends a first signal to a passive target on a first channel.

[0150] The first signal may include two carriers, and the two carriers correspond to the first channel. It can also be understood that the frequencies of the two carriers are determined according to the information of the first channel.

[0151] It should be understood that STA#1 does not know the specific direction of the passive target, so STA#1 sends the first signal in different directions in turn.

[0152] S1420, STA#1 receives a first signal reflected by a passive target on a first channel.

[0153] S1430, STA#1 calculates the distance between the passive target and STA#1.

[0154] After STA#1 receives the first signal reflected by the passive target, it can first use full-duplex technology to eliminate the influence of the first signal reflected by itself, so as to obtain a pure reflected signal.

[0155] Then, STA#1 calculates the distance between STA#1 and the passive target based on the phase difference between the carrier waves of the first signal reflected by the passive target, and combines the direction of the first signal sent previously to determine the specific location of the passive target.

[0156] In an embodiment of the present application, when no other device can cooperate with the first device, the first device can also determine the position of the passive target based on the phase difference between the carrier waves of the first signal reflected by the passive target.

[0157] Above, combined Figures 8 to 14 The method provided by the embodiment of the present application is described in detail. Figure 15 to Figure 16 The device provided in the embodiments of the present application is described in detail.

[0158] Fig.15 is a schematic block diagram of a distance measuring device provided in an embodiment of the present application. Fig.15 As shown, the distance measuring device 2000 may include a processing unit 2100 and a transceiver unit 2200 .

[0159] In a possible design, the ranging device 2000 may correspond to the first device in the above method embodiment, for example, it may be the first device, or a component (such as a chip or a chip system) configured in the first device.

[0160] It should be understood that the distance measuring device 2000 may correspond to the first device in the method 800, the method 1200, and the method 1400 according to the embodiment of the present application, and the distance measuring device 2000 may include a device for performing Figure 8 Method 800, Fig.12 Method 1200, Fig.14 The units of the method performed by the first device in the method 1400 in the embodiment. Furthermore, the units in the distance measuring device 2000 and the above-mentioned other operations and / or functions are respectively for implementing Figure 8 Method 800, Fig.12 Method 1200, Fig.14 The corresponding process of method 1400 in .

[0161] Wherein, when the distance measuring device 2000 is used to perform Figure 8 When the method 800 in the embodiment is performed, the processing unit 2100 can be used to execute step S830 in the method 800, and the transceiver unit 2200 can be used to execute S810-S820 and S840-S850 in the method 800. It should be understood that the specific process of each unit executing the above corresponding steps has been described in detail in the above method embodiment, and for the sake of brevity, it will not be repeated here.

[0162] When the distance measuring device 2000 is used to perform Fig.12 When the method 1200 in the embodiment is performed, the processing unit 2100 can be used to execute step S1230 in the method 800, and the transceiver unit 2200 can be used to execute S1210-S1220 and S1240-S1250 in the method 1200. It should be understood that the specific process of each unit executing the above corresponding steps has been described in detail in the above method embodiment, and for the sake of brevity, it will not be repeated here.

[0163] When the distance measuring device 2000 is used to perform Fig.14 When the method 1400 in the embodiment is used, the processing unit 2100 can be used to execute step S1430 in the method 800, and the transceiver unit 2200 can be used to execute S1410 to S1420 in the method 1400. It should be understood that the specific process of each unit executing the above corresponding steps has been described in detail in the above method embodiment, and for the sake of brevity, it will not be repeated here.

[0164] It should also be understood that when the communication device 2000 is a chip or a chip system configured in the first device, the transceiver unit 2200 in the ranging device 2000 can be implemented through an input / output interface, and the processing unit 2100 in the ranging device 2000 can be implemented through a processor, microprocessor or integrated circuit integrated on the chip or chip system.

[0165] In another possible design, the ranging device 2000 may correspond to the second device in the above method embodiment, for example, it may be the second device, or a component (such as a chip or a chip system) configured in the second device.

[0166] It should be understood that the distance measuring device 2000 may correspond to the second device of the method 800 or the method 1200 according to the embodiment of the present application, and the distance measuring device 2000 may include a method for executing Figure 8 Method 800, Fig.12 The units of the method performed by the second device in the method 1200 in the embodiment. Furthermore, the units in the distance measuring device 2000 and the above-mentioned other operations and / or functions are respectively for realizing Figure 8Method 800, Fig.12 The corresponding process of method 1200 in .

[0167] Wherein, when the distance measuring device 2000 is used to perform Figure 8 When the method 800 in the embodiment is used, the processing unit 2100 can be used to execute step S820 in the method 800, and the transceiver unit 2200 can be used to execute S810-S820 and S840-S850 in the method 800. It should be understood that the specific process of each unit executing the above corresponding steps has been described in detail in the above method embodiment, and for the sake of brevity, it will not be repeated here.

[0168] When the distance measuring device 2000 is used to perform Fig.12 When the method 1200 in the embodiment is performed, the processing unit 2100 can be used to execute step S1220 in the method 800, and the transceiver unit 2200 can be used to execute S1210-S1220 and S1240-S1250 in the method 800. It should be understood that the specific process of each unit executing the above corresponding steps has been described in detail in the above method embodiment, and for the sake of brevity, it will not be repeated here.

[0169] It should also be understood that when the communication device 2000 is a chip or a chip system configured in the second device, the transceiver unit 2200 in the ranging device 2000 can be implemented through an input / output interface, and the processing unit 2100 in the ranging device 2000 can be implemented through a processor, microprocessor or integrated circuit integrated on the chip or chip system.

[0170] Fig.16 A schematic block diagram of a distance measuring device 3000 provided in an embodiment of the present application is shown. The distance measuring device 3000 can be applied to Figure 1 In the system shown, the functions of the first device or the second device in the above method embodiment are performed. Fig.16 As shown, the distance measuring device 3000 includes a processor 3100 and a transceiver 3200, the processor 3100 and the transceiver 3200 are connected, and optionally, the distance measuring device 3000 also includes a memory 3300, and the memory 3300 is connected to the processor 3100. The processor 3100, the memory 3300 and the transceiver 3200 can communicate with each other through an internal connection path.

[0171] The processor 3100 can be used to perform the actions implemented by the first device described in the previous method embodiment, such as calculating the distance, etc. The transceiver 3200 can be used to perform the actions sent or received by the first device described in the previous method embodiment, such as sending a first signal, receiving a second signal, etc. For details, please refer to the description in the previous method embodiment, which will not be repeated here.

[0172] It should be understood that Fig.16The distance measuring device 3000 shown can achieve Figure 8 , Fig.12 , Fig.14 The illustrated method embodiment involves various processes of the first device. The operations and / or functions of various modules in the ranging device 3000 are respectively to implement the corresponding processes in the above method embodiment. For details, please refer to the description in the above method embodiment. To avoid repetition, the detailed description is appropriately omitted here.

[0173] The processor 3100 can be used to perform the actions implemented by the second device described in the previous method embodiment, such as frequency conversion of the first signal, etc. The transceiver 3200 can be used to perform the actions sent or received by the second device described in the previous method embodiment, such as sending the second signal, receiving the first signal, etc. For details, please refer to the description in the previous method embodiment, which will not be repeated here.

[0174] It should be understood that Fig.16 The distance measuring device 3000 shown can achieve Figure 8 , Fig.12 The method embodiment shown involves various processes of the second device. The operations and / or functions of each module in the ranging device 3000 are respectively to implement the corresponding processes in the above method embodiment. For details, please refer to the description in the above method embodiment. To avoid repetition, the detailed description is appropriately omitted here.

[0175] An embodiment of the present application also provides a processing device, including a processor and an interface; the processor is used to execute the method in any of the above method embodiments.

[0176] It should be understood that the above-mentioned processing device can be one or more chips. For example, the processing device can be a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a system on chip (SoC), a central processor unit (CPU), a network processor (NP), a digital signal processor (DSP), a microcontroller unit (MCU), a programmable logic device (PLD) or other integrated chips. In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in the processor or an instruction in the form of software. The steps of the method disclosed in conjunction with the embodiment of the present application can be directly embodied as a hardware processor to be executed, or a combination of hardware and software modules in the processor to be executed. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor reads the information in the memory and completes the steps of the above method in conjunction with its hardware. To avoid repetition, it is not described in detail here.

[0177] It should be noted that the processor in the embodiment of the present application can be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method embodiment can be completed by an integrated logic circuit of hardware in the processor or an instruction in the form of software. The above processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in the embodiment of the present application can be directly embodied as a hardware decoding processor to perform, or the hardware and software modules in the decoding processor can be combined and performed. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0178] It can be understood that the memory in the embodiments of the present application can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory can be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), and direct RAM (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0179] According to the method provided in the embodiment of the present application, the present application also provides a computer program product, which includes: a computer program code, when the computer program code is run on a computer, the computer executes Figure 8 , Fig.12 as well as Fig.14 The methods respectively executed by the first device and the second device in the illustrated embodiment.

[0180] According to the method provided in the embodiment of the present application, the present application also provides a computer-readable medium, which stores a program code, and when the program code is run on a computer, the computer executes Figure 8 , Fig.12 as well as Fig.14 The methods respectively executed by the first device and the second device in the illustrated embodiment.

[0181] According to the method provided in the embodiment of the present application, the present application also provides a system, which includes the aforementioned one or more first devices and one or more second devices.

[0182] The first device and the second device in the above-mentioned various apparatus embodiments completely correspond to the first device and the second device in the method embodiment, and the corresponding modules or units perform the corresponding steps. For example, the transceiver unit (transceiver) performs the steps of receiving or sending in the method embodiment, and the other steps except sending and receiving can be performed by the processing unit (processor). The functions of the specific units can refer to the corresponding method embodiments. Among them, there can be one or more processors.

[0183] Those of ordinary skill in the art will appreciate that the various illustrative logical blocks and steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or in a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0184] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0185] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0186] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0187] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage media include: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROM), random access memories (RAM), magnetic disks or optical disks.

Claims

1. A distance measuring device, characterized in that: Including transceiver unit and processing unit: The transceiver unit is used to: send a first OFDM signal on a first channel, wherein the first OFDM signal includes a plurality of repeated long training field LTF symbols, and the LTF symbol does not include a guard interval; The transceiver unit is further used to: receive a second OFDM signal from a second device on a second channel, where the second OFDM signal is a signal obtained by frequency conversion of the first OFDM signal; The processing unit is used to: calculate the distance between the apparatus and the second device according to the phase difference between the carriers of the second OFDM signal, Wherein, the distance d between the device and the second device is: Where c is the speed of light, is the phase of the kth subcarrier in the second OFDM signal, is the phase of the k-1th subcarrier in the second OFDM signal, is the frequency interval between the kth subcarrier and the k-1th subcarrier.

2. A distance measuring device, characterized in that: Including transceiver unit and processing unit: The transceiver unit is used to: send a first OFDM signal to a passive target on a first channel, wherein the first OFDM signal includes a plurality of repeated long training field LTF symbols, and the LTF symbols do not include a guard interval; The transceiver unit is further used to: receive a second OFDM signal from a second device on a second channel, where the second OFDM signal is a signal obtained by frequency conversion of the first OFDM signal; The processing unit is used to calculate the sum of the distance from the passive target to the device and the distance from the passive target to the second device according to the phase difference between the carriers of the second OFDM signal, The sum of the distance from the passive target to the device and the distance to the second device is Dd, where D is the sum of the propagation distances of the first OFDM signal and the second OFDM signal, d is the distance between the device and the second device, and the value of d is: Where c is the speed of light, is the phase of the kth subcarrier in the second OFDM signal, is the phase of the k-1th subcarrier in the second OFDM signal, is the frequency interval between the k-th subcarrier and the k-1-th subcarrier; The processing unit is further used to determine the position of the passive target according to the sum of the sending direction of the first OFDM signal and the distance.

3. The device according to claim 1 or 2, characterized in that: The transceiver unit is also used for: A ranging request frame is sent, where the ranging request frame includes information about the first channel and information about the second channel.

4. The device according to claim 3, characterized in that The transceiver unit is also used for: receiving a ranging request response frame from the second device, where the ranging request response frame is sent by the second device according to the ranging request frame, and the ranging request response frame includes available ranging time period information, where the available ranging time period information is used to indicate a first time period; and The transceiver unit is specifically used for: During the first time period, the first OFDM signal is sent on the first channel.

5. The device according to claim 3 or 4, characterized in that The ranging request frame also carries at least one of the following information: Ranging method information, and duration information of the first OFDM signal.

6. The device according to any one of claims 3 to 5, characterized in that The information of the first channel includes at least one of the following information: bandwidth of the first channel, frequency of the first channel, and channel number of the first channel. The information of the second channel includes at least one of the following information: The bandwidth of the second channel, the frequency of the second channel, and the channel number of the second channel.

7. A distance measuring device, characterized in that: Including transceiver unit and processing unit: The transceiver unit is used to: receive a first OFDM signal from a first device on a first channel, wherein the first OFDM signal includes a plurality of repeated long training field LTF symbols, and the LTF symbol does not include a guard interval; The processing unit is used to: perform frequency conversion on the first OFDM signal to obtain a second OFDM signal; The transceiver unit is further used to: send the second OFDM signal on the second channel, and the phase difference between the carriers of the second OFDM signal is used to calculate the distance between the first device and the apparatus, Wherein, the distance d between the first device and the apparatus is: Where c is the speed of light, is the phase of the kth subcarrier in the second OFDM signal, is the phase of the k-1th subcarrier in the second OFDM signal, is the frequency interval between the kth subcarrier and the k-1th subcarrier.

8. The device according to claim 7, characterized in that The transceiver unit is also used for: A ranging request frame is received from a first device, where the ranging request frame includes information about the first channel and information about the second channel.

9. The device according to claim 8, characterized in that The transceiver unit is also used for: Sending a ranging request response frame according to the ranging request frame, wherein the ranging request response frame includes available ranging time period information, and the available ranging time period information is used to indicate a first time period; and The transceiver unit is specifically used for: During the first time period, the first OFDM signal is received on the first channel.

10. The device according to claim 8 or 9, characterized in that The ranging request frame also carries at least one of the following information: Ranging method information, and duration information of the first OFDM signal.

11. The device according to any one of claims 8 to 10, characterized in that The information of the first channel includes at least one of the following information: bandwidth of the first channel, frequency of the first channel, and channel number of the first channel. The information of the second channel includes at least one of the following information: The bandwidth of the second channel, the frequency of the second channel, and the channel number of the second channel.

12. A distance measurement method, characterized in that: include: The first device sends a first OFDM signal on a first channel, wherein the first OFDM signal includes a plurality of repeated long training field LTF symbols, and the LTF symbols do not include a guard interval; The first device receives a second OFDM signal from a second device on a second channel, where the second OFDM signal is a frequency-converted signal of the first OFDM signal; The first device calculates the distance between the first device and the second device according to the phase difference between the carriers of the second OFDM signal, The distance d between the first device and the second device is: Where c is the speed of light, is the phase of the kth subcarrier in the second OFDM signal, is the phase of the k-1th subcarrier in the second OFDM signal, is the frequency interval between the kth subcarrier and the k-1th subcarrier.

13. A distance measurement method, characterized in that: include: The first device sends a first OFDM signal to a passive target on a first channel, wherein the first OFDM signal includes a plurality of repeated long training field LTF symbols, and the LTF symbols do not include a guard interval; The first device receives a second OFDM signal from a second device on a second channel, where the second OFDM signal is a frequency-converted signal of the first OFDM signal; The first device calculates the sum of the distance from the passive target to the first device and the distance from the passive target to the second device according to the phase difference between the carriers of the second OFDM signal, The sum of the distance from the passive target to the first device and the distance from the passive target to the second device is Dd, where D is the sum of the propagation distances of the first OFDM signal and the second OFDM signal, d is the distance between the first device and the second device, and the value of d is: Where c is the speed of light, is the phase of the kth subcarrier in the second OFDM signal, is the phase of the k-1th subcarrier in the second OFDM signal, is the frequency interval between the k-th subcarrier and the k-1-th subcarrier; The first device determines the position of the passive target according to the sum of the sending direction of the first OFDM signal and the distance.

14. The method according to claim 12 or 13, characterized in that The method further comprises: The first device sends a ranging request frame, where the ranging request frame includes information about the first channel and information about the second channel.

15. The method according to claim 14, characterized in that The method further comprises: The first device receives a ranging request response frame from the second device, where the ranging request response frame is sent by the second device according to the ranging request frame, and the ranging request response frame includes available ranging time period information, where the available ranging time period information is used to indicate a first time period; and The first device sends a first OFDM signal on a first channel, including: During the first time period, the first device sends the first OFDM signal on the first channel.

16. The method according to claim 14 or 15, characterized in that The ranging request frame also carries at least one of the following information: Ranging method information, and duration information of the first OFDM signal.

17. The method according to any one of claims 14 to 16, characterized in that The information of the first channel includes at least one of the following information: bandwidth of the first channel, frequency of the first channel, and channel number of the first channel. The information of the second channel includes at least one of the following information: The bandwidth of the second channel, the frequency of the second channel, and the channel number of the second channel.

18. A distance measurement method, characterized in that: include: The second device receives a first OFDM signal from the first device on the first channel, wherein the first OFDM signal includes a plurality of repeated long training field LTF symbols, and the LTF symbols do not include a guard interval; The second device performs frequency conversion on the first OFDM signal to obtain a second OFDM signal; The second device sends the second OFDM signal on a second channel, and the phase difference between carriers of the second OFDM signal is used to calculate the distance between the first device and the second device. The distance d between the first device and the second device is: Where c is the speed of light, is the phase of the kth subcarrier in the second OFDM signal, is the phase of the k-1th subcarrier in the second OFDM signal, is the frequency interval between the kth subcarrier and the k-1th subcarrier.

19. The method according to claim 18, characterized in that The method further comprises: The second device receives a ranging request frame from the first device, where the ranging request frame includes information of the first channel and information of the second channel.

20. The method according to claim 19, characterized in that The method further comprises: The second device sends a ranging request response frame according to the ranging request frame, where the ranging request response frame includes available ranging time period information, where the available ranging time period information is used to indicate a first time period; and The second device receives a first OFDM signal on a first channel, including: During the first time period, the second device receives the first OFDM signal on the first channel.

21. The method according to claim 19 or 20, characterized in that The ranging request frame also carries at least one of the following information: Ranging method information, and duration information of the first OFDM signal.

22. The method according to any one of claims 19 to 21, characterized in that The information of the first channel includes at least one of the following information: bandwidth of the first channel, frequency of the first channel, and channel number of the first channel. The information of the second channel includes at least one of the following information: The bandwidth of the second channel, the frequency of the second channel, and the channel number of the second channel.

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