Wireless sensing method and apparatus

Abstract

Disclosed are a wireless sensing method and apparatus, which belong to the technical field of sensing. An AP in a WLAN uses a first antenna to send a beacon frame, and uses a second antenna to receive an echo signal, wherein the echo signal is obtained by reflecting or scattering the beacon frame; and the AP then performs environmental sensing on the basis of the received echo signal. The present application utilizes the AP's capability of receiving and sending a message on its own, the same AP sends the beacon frame and receives the echo signal of the beacon frame, and with respect to the AP, a signal receiving and sending position is always known, thus helping to improve the precision of environmental sensing; and the position where the AP is deployed is not limited, and thus the AP can be flexibly applied to various scenarios. In addition, the beacon frame is sent periodically to announce the presence of the AP. Therefore, the AP utilizes the beacon frame to realize environmental sensing, without the need to additionally send packets, such that channel resources can be saved on, and environmental sensing can be completed in a normal communication process, thus realizing integrated sensing and communication.

Description

Wireless sensing method and device

[0001] This application claims priority to Chinese patent application number 202311279386.X, filed on September 28, 2023, with invention name “Wireless Sensing Method and Device,” the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of sensing technology, and in particular to a wireless sensing method and device. Background Art

[0003] Wireless sensing refers to the technology used to detect people or objects in an environment by measuring changes in the scattering and / or reflection of wireless signals passing through them. Current research focuses on how to achieve environmental sensing based on wireless local area networks (WLANs), such as detecting intrusion or breathing.

[0004] Summary of the Invention

[0005] The present application provides a wireless sensing method and device, which can realize environmental perception based on WLAN.

[0006] In a first aspect, a wireless sensing method is provided. The method includes: an access point (AP) in a WLAN transmits a beacon frame using a first antenna. The AP receives an echo signal using a second antenna, the echo signal being obtained by reflection or scattering of the beacon frame. The AP performs environmental sensing based on the received echo signal.

[0007] This application utilizes the ability of the AP to send and receive messages by itself. The same AP sends a beacon frame and receives the echo signal of the beacon frame. Compared to the AP, the signal sending and receiving location is always known, which helps to improve the accuracy of environmental perception. The deployment location of the AP is not restricted and can be flexibly applied to various scenarios. In addition, the AP uses beacon frames to achieve environmental perception. Beacon frames are sent periodically to announce the presence of the AP. Therefore, using beacon frames to achieve environmental perception does not require additional packets, which can save channel resources. In addition, environmental perception can be completed during normal communication, realizing integrated communication and perception.

[0008] Optionally, the first antenna and the second antenna are different antennas connected to the same baseband circuit of the AP.

[0009] In this implementation, because the first and second antennas are connected to the same baseband circuit of the AP via the same RF circuit, a common local oscillator design is achieved for the transmitting and receiving circuits. This ensures that the sampling frequency and carrier frequency between the transmitting and receiving ends are consistent, eliminating the problem of sampling frequency offset and carrier frequency offset affecting the CSI quality of the received signal, thereby improving environmental perception accuracy. Furthermore, internal time synchronization is no longer required, thereby improving environmental perception efficiency.

[0010] Optionally, the first antenna and the second antenna are respectively connected to different baseband circuits of the AP.

[0011] Optionally, an implementation manner in which the AP sends the beacon frame using the first antenna includes: the AP sends the beacon frame using the first antenna on the primary channel and the secondary channel simultaneously.

[0012] In this application, the AP can copy the beacon frame transmitted on the main channel to one or more secondary channels and transmit them simultaneously, so that the beacon frame is transmitted on a larger bandwidth, so that the AP can receive the echo signal obtained by the beacon frame reflected or scattered by the environment on a larger bandwidth, thereby improving the perception accuracy.

[0013] Optionally, an implementation of an AP performing environmental perception based on a received echo signal includes: the AP calculating channel state information (CSI) based on the received echo signal. The AP performs amplitude and phase compensation on the CSI based on a preset amplitude and phase compensation relationship and according to an automatic gain control (AGC) level corresponding to the echo signal, where the amplitude and phase compensation relationship includes amplitude compensation values ​​and / or phase compensation values ​​corresponding to multiple AGC levels. The AP performs environmental perception based on the amplitude and phase compensated CSI.

[0014] In this application, by pre-establishing an amplitude-phase compensation relationship, the AGC gear corresponding to the echo signal is used to perform amplitude-phase compensation on the CSI calculated based on the echo signal, which can minimize the impact of the dynamic variables of the CSI introduced by the AGC gear on environmental perception.

[0015] In a second aspect, an AP in a WLAN is provided. The AP includes multiple functional modules that interact with each other to implement the method of the first aspect and its respective embodiments. The multiple functional modules can be implemented based on software, hardware, or a combination of software and hardware, and the multiple functional modules can be arbitrarily combined or divided based on the specific implementation.

[0016] For example, the AP includes a transmitting module, a receiving module, and a processing module. The transmitting module is configured to transmit a beacon frame using a first antenna. The receiving module is configured to receive an echo signal using a second antenna, the echo signal being obtained by reflection or scattering of the beacon frame. The processing module is configured to perform environmental sensing based on the received echo signal.

[0017] Optionally, the first antenna and the second antenna are different antennas connected to the same baseband circuit of the AP.

[0018] Optionally, the first antenna and the second antenna are respectively connected to different baseband circuits of the AP.

[0019] Optionally, the sending module is specifically configured to: use the first antenna to simultaneously send the beacon frame on a primary channel and a secondary channel.

[0020] Optionally, the processing module is specifically used to: calculate the CSI based on the received echo signal; based on a preset amplitude-phase compensation relationship, perform amplitude-phase compensation on the CSI according to the AGC gear corresponding to the echo signal, the amplitude-phase compensation relationship including amplitude compensation values ​​and / or phase compensation values ​​corresponding to multiple AGC gears; and perform environmental perception based on the CSI after amplitude-phase compensation.

[0021] In a third aspect, an AP in a WLAN is provided, wherein the AP includes a processor, a memory, a transceiver, and multiple antennas.

[0022] The transceiver is configured to transmit a beacon frame using a first antenna among the multiple antennas. The transceiver is further configured to receive an echo signal using a second antenna among the multiple antennas, the echo signal being obtained by reflection or scattering of the beacon frame. The processor is configured to invoke a computer program stored in the memory to perform environmental perception based on the received echo signal.

[0023] Optionally, the first antenna and the second antenna are different antennas of the AP. For example, the first antenna and the second antenna are different antennas connected to the same baseband circuit of the AP. Alternatively, the first antenna and the second antenna are respectively connected to different baseband circuits of the AP.

[0024] In a fourth aspect, a computer-readable storage medium is provided, on which instructions are stored. When the instructions are executed by a processor of an AP, the method in the above-mentioned first aspect and its various embodiments is implemented.

[0025] In a fifth aspect, a chip is provided, which includes a programmable logic circuit and / or program instructions. When the chip is running, it implements the method in the above-mentioned first aspect and its various embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a schematic diagram of an application scenario provided by an embodiment of the present application;

[0027] FIG2 is a schematic diagram of the hardware structure of an AP provided in an embodiment of the present application;

[0028] FIG3 is a schematic diagram of the hardware structure of another AP provided in an embodiment of the present application;

[0029] FIG4 is a flow chart of a wireless sensing method provided in an embodiment of the present application;

[0030] FIG5 is a schematic diagram of the structure of an AP provided in an embodiment of the present application. DETAILED DESCRIPTION

[0031] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0032] WLANs can use CSI for environmental awareness, referred to as CSI sensing. CSI data contains channel characteristics such as scattering, fading, and energy attenuation with distance. Objects moving in the environment affect signal propagation, and these changes are recorded by CSI as they change the channel. Therefore, CSI can be used to implement functions such as detection, positioning, and identification. CSI sensing technology has many advantages, including indoor ubiquity, privacy protection, fine-grained perception, and environmental robustness. CSI sensing technology has many application scenarios, such as health monitoring and smart homes.

[0033] The Institute of Electrical and Electronics Engineers (IEEE) 802.11bf draft protocol proposes providing wireless sensing capabilities for WLAN technology while minimizing the impact on communications. The current IEEE 802.11bf draft protocol primarily discusses multi-station networking to enable the acquisition of CSI data. Multi-station networking can involve a WLAN device that supports sending WLAN signals and a WLAN device that supports measuring CSI, such as AP-to-AP networking, AP-to-Internet of Things (IoT) device networking, or IoT device-to-IoT device networking. Simply put, in a multi-station networking scenario, one WLAN device transmits wireless signals, and another WLAN device calculates CSI based on the received wireless signals to further achieve environmental awareness.

[0034] For example, one WLAN device periodically transmits wireless signals, while another WLAN device calculates CSI based on the received signals. It then uses a model-based or learning-based approach to analyze the continuous CSI data acquired over time to perceive human activity in the environment. The model-based approach models human activity based on physical model signals, such as Fresnel zone theory. The learning-based approach is driven by data and machine learning. For difficult-to-model human activities, such as fall detection, large amounts of data can be collected to train a machine learning model.

[0035] However, both model-based and learning-based approaches are dependent on the topology of the multi-station network. For model-based approaches, an unknown topology can affect environmental perception accuracy. For learning-based approaches, changes in topology can invalidate previously trained machine learning models. Therefore, when the topology of a multi-station network is unknown, using two WLAN devices to transmit and receive signals separately may not achieve accurate environmental perception.

[0036] In addition, in a multi-station networking scenario, multiple WLAN devices need to measure CSI data from each other. On the one hand, if the clocks between the receiving and transmitting ends are not synchronized, the sampling frequency and carrier frequency between the receiving and transmitting ends may be different, and the CSI quality will be affected by factors such as the sampling frequency offset (SFO) and the carrier frequency offset (CFO), thereby affecting the accuracy of environmental perception. On the other hand, different WLAN devices may be limited by different-frequency networking or the carrier-sense multiple access with collision avoidance (CSMA / CA) mechanism, and it is impossible to obtain more CSI data relative to the same WLAN device within a period of time, resulting in lower environmental perception accuracy.

[0037] Based on this, the present application provides a technical solution applied to WLAN. The AP uses a first antenna to send a beacon frame, and uses a second antenna to receive an echo signal obtained by reflecting or scattering the beacon frame, and further performs environmental perception based on the received echo signal. Among them, the first antenna and the second antenna can be different antennas in the AP. The present application utilizes the ability of the AP to send and receive messages by itself. The same AP sends a beacon frame and receives the echo signal of the beacon frame. Compared with the AP, the signal sending and receiving position is always known, which helps to improve the accuracy of environmental perception, and the deployment position of the AP is not restricted and can be flexibly applied to various scenarios. In addition, the AP uses beacon frames to achieve environmental perception. Beacon frames are sent periodically to announce the existence of the AP. Therefore, the use of beacon frames to achieve environmental perception does not require additional packet transmission, which can save channel resources, and can complete environmental perception during normal communication, realizing integrated communication and perception.

[0038] The following is a detailed introduction to the technical solution of this application from multiple perspectives such as application scenarios, hardware structure, method flow, and virtual devices.

[0039] The following examples illustrate the application scenarios and hardware structures involved in the embodiments of the present application.

[0040] The wireless sensing method provided in the embodiments of the present application can be applied to various application scenarios where WLAN is deployed, such as intrusion detection and respiration detection in an environment, and can be applied to both indoor and outdoor environments. For example, FIG1 is a schematic diagram of an application scenario provided in the embodiments of the present application. As shown in FIG1 , the application scenario includes an AP 100. AP 100 is a network device that supports the WLAN protocol. For example, AP 100 can be a wireless router, etc. AP 100 is used to provide wireless access services based on the WLAN protocol for stations (STAs). The WLAN protocol is defined in the IEEE 802.11 series of standards.

[0041] Optionally, the operating frequency bands supported by AP 100 include, but are not limited to, the 2.4 GHz band, the 3.6 GHz band, the 4.9 GHz band, the 5 GHz band, the 6 GHz band, or the 60 GHz band. The 2.4 GHz band includes 2.4 GHz to 2.4835 GHz, and the 5 GHz band includes 5.150 GHz to 5.350 GHz and 5.725 GHz to 5.850 GHz. To avoid co-channel interference, the available frequency bands in a WLAN are divided into independent channels, meaning there is no frequency overlap between channels. For example, the 2.4 GHz band has three independent channels, including channel 1, channel 6, and channel 11. Therefore, up to three different-frequency WLANs can be deployed simultaneously in the 2.4 GHz band. In this embodiment of the present application, the "x" in "channel x" refers to the channel number defined in the WLAN protocol. For example, the 5 GHz band includes channel 36, channel 40, channel 44, and channel 48.

[0042] The operating channel of AP 100 includes at least a primary channel. Optionally, the operating channel of AP 100 also includes a secondary channel. In the embodiments of the present application, the operating channel of AP 100 refers to a complete WLAN channel, such as a 20 MHz WLAN channel, or a WLAN channel with a larger bandwidth (such as 40 MHz, 80 MHz, or 160 MHz). A channel with a bandwidth greater than 20 MHz is referred to as a large-bandwidth channel, which consists of multiple consecutive 20 MHz channels. For example, in the 5 GHz frequency band, a 40 MHz large-bandwidth channel can be composed of 20 MHz channel 36 and 20 MHz channel 40, represented as channels <36, 40>. If the operating channel of AP 100 is a large-bandwidth channel, the operating channel of AP 100 may include a primary channel and a secondary channel. Any 20 MHz channel in the operating channel of AP 100 can be set as the primary channel. Channels in the operating channel of AP 100 other than the primary channel are secondary channels. To improve WLAN service quality, the AP may use a large-bandwidth channel as its operating channel, such as a WLAN channel with a bandwidth of 40 MHz or greater. If AP 100's operating channel is configured as a large-bandwidth channel, AP 100 can use part or all of the operating channel's bandwidth each time it transmits a WLAN frame, but this must include the primary channel. For example, if AP 100's operating channel is configured as 80 MHz channels <36, 40, 44, 48>, with channel 36 as the primary channel, AP 100 can transmit WLAN frames on the entire 80 MHz channel, on the 40 MHz channels <36, 40>, or on the 20 MHz channel 36. WLAN frames include management frames, control frames, and data frames. Management frames include, but are not limited to, beacon frames.

[0043] In this embodiment, AP 100 implements monostatic sensing, meaning that only one device participates in environmental sensing. AP 100 senses the environment by transmitting and receiving signals, similar to the operation of traditional radar. For example, referring to Figure 1 , AP 100 transmits a beacon frame. This beacon frame is scattered and / or reflected by the environment, generating an echo signal. AP 100 then receives the echo signal and analyzes it to further achieve environmental perception.

[0044] Optionally, please continue to refer to Figure 1. The application scenario also includes a wireless controller 110 and / or a server 120. The wireless controller 110 is used to manage the AP 100, including performing radio frequency tuning, air interface optimization, and security authentication on the AP 100. The wireless controller 110 can be, for example, an access controller (AC). The server 120 is used to provide services for the AP 100, including but not limited to access services. In the embodiment of the present application, after receiving the echo signal of the beacon frame, the AP 100 can independently complete environmental perception, or can cooperate with the wireless controller 110 or the server 120 to complete environmental perception. For example, the AP 100 can send the collected CSI data to the wireless controller 110 or the server 120, and the wireless controller 110 or the server 120 can perceive the changes in the environment by analyzing the changes in the CSI data.

[0045] Optionally, AP 100 includes multiple antennas. For example, Figures 2 and 3 are schematic diagrams of the hardware structure of an AP provided in an embodiment of the present application. As shown in Figure 2 or Figure 3, AP 100 includes: a processor 101, a memory 102, a transceiver 103, and multiple antennas. For example, referring to Figure 2, AP 100 includes two antennas, namely antenna A1 and antenna A2. For another example, referring to Figure 3, AP 100 includes four antennas, namely antenna B1, antenna B2, antenna B3, and antenna B4. The number of antennas in Figures 2 and 3 is for illustrative purposes only and does not limit the AP provided in the embodiment of the present application.

[0046] The processor 101 , the memory 102 and the transceiver 103 are connected via a communication bus (not shown in the figure).

[0047] Processor 101 may be a general-purpose central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits used to control the execution of the solution of the present application. Processor 101 may be a single-core (single-CPU) processor or a multi-core (multi-CPU) processor. Processor 101 herein may refer to one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0048] The memory 102 may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, an optical disc storage (including a compact disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory 102 may exist independently and be connected to the processor 101 via a communication bus. The memory 102 may also be integrated with the processor 101.

[0049] In the embodiment of the present application, the memory 102 is used to store a computer program including program instructions. The processor 101 is used to call the computer program and cooperate with the transceiver 103 to implement the wireless sensing method provided in the following embodiments of the present application.

[0050] The transceiver 103 is used to perform the transceiver action of the device. Optionally, the transceiver 103 includes one or more baseband circuits and one or more radio frequency circuits. For example, referring to Figure 2, the transceiver 103 includes a baseband circuit (baseband circuit 21) and a radio frequency circuit (radio frequency circuit 22). For another example, referring to Figure 3, the transceiver 103 includes two baseband circuits (baseband circuit 311 and baseband circuit 312) and two radio frequency circuits (radio frequency circuit 321 and radio frequency circuit 322), wherein the baseband circuit 311 is connected to the radio frequency circuit 321, and the baseband circuit 312 is connected to the radio frequency circuit 322. Figure 3 illustrates an example of multiple baseband circuits being integrated into the same transceiver 103, or the AP 100 may also include multiple transceivers, and the multiple baseband circuits may be independently deployed in different transceivers of the AP 100.

[0051] Referring to Figure 2 or Figure 3, each baseband circuit includes a signal generating circuit and a signal receiving circuit. The signal generating circuit and the signal receiving circuit can be two independent circuits, or the signal generating circuit and the signal receiving circuit can also share some circuits. The signal generating circuit is used to generate and send signals. The signal receiving circuit is used to receive and process signals. The baseband circuits shown in Figures 2 and 3 are implemented based on hardware. In some implementations, the baseband processing function can also be implemented based on software. For example, the baseband processing function can be implemented in a processor, that is, a baseband processing module is integrated into the processor, which is not limited in the embodiments of the present application. For the sake of distinction, this application refers to the hardware that implements the baseband processing function as a baseband circuit, and the software that implements the baseband processing function as a baseband processing module.

[0052] Optionally, the RF circuit may include one or more channels (chains). The baseband circuit may enable a channel in the RF circuit to be a transmit (Tx) channel or a receive (Rx) channel. Optionally, the transmit channel may include filters, digital-to-analog converters, and power amplifiers. The receive channel may include filters, analog-to-digital converters, and power amplifiers. The transmit and receive channels may be independent or share some components.

[0053] For example, referring to Figure 2, the RF circuit 22 includes channel 22a and channel 22b. When AP 100 performs environmental sensing, channel 22a can be enabled as a transmit channel and channel 22b as a receive channel through baseband circuit 21. Channel 22a is connected to the signal generation circuit and antenna A1, meaning antenna A1 functions as a transmit antenna. Channel 22b is connected to the signal reception circuit and antenna A2, meaning antenna A2 functions as a receive antenna. The signal generated by the signal generation circuit in baseband circuit 21 is transmitted along channel 22a in RF circuit 22 and then sent out by antenna A1. The signal received by antenna A2 is transmitted via channel 22b in RF circuit 22 to the signal reception circuit in baseband circuit 21. The signal is then processed by the signal reception circuit or transmitted to processor 101 for processing. For example, antenna A1 can transmit a beacon frame, and antenna A2 can receive the beacon frame and the echo signal generated by environmental scattering or reflection. Figure 2 illustrates an example in which the RF circuit 22 includes two channels. However, the RF circuit 22 can also include three or more channels. Accordingly, the RF circuit 22 can be connected to three or more antennas. When the AP 100 performs environmental sensing, the baseband circuit 21 can enable one antenna connected to the RF circuit 22 as a transmitting antenna, while the remaining antennas are receiving antennas. Alternatively, multiple antennas connected to the RF circuit 22 can be enabled as transmitting antennas, while the remaining antennas are receiving antennas. This is accomplished as long as the multiple antennas connected to the baseband circuit 21 through the RF circuit 22 include both transmitting and receiving antennas.

[0054] For example, referring to Figure 3, RF circuit 321 includes channel 321a and channel 321b. When AP 100 performs environmental sensing, baseband circuit 311 can enable channels 321a and 321b as transmit channels, and baseband circuit 312 can enable channels 322a and 322b as receive channels. Channels 321a and 321b are each connected to a signal generation circuit, with channel 321a connected to antenna B1 and channel 321b connected to antenna B2. Antennas B1 and B2 function as transmit antennas. Channels 322a and 322b are each connected to a signal reception circuit, with channel 322a connected to antenna B3 and channel 322b connected to antenna B4. Antennas B3 and B4 function as receive antennas. Signals generated by the signal generation circuit in baseband circuit 311 are transmitted along channels 321a and 321b in RF circuit 321 and transmitted by antennas B1 and B2, respectively. The signals received by antenna B3 and antenna B4 are transmitted to the signal receiving circuit in baseband circuit 312 through channel 322a and channel 322b in RF circuit 322, respectively. The signals are then processed by the signal receiving circuit or further transmitted to processor 101 for processing by processor 101. For example, antenna B1 and antenna B2 can send a beacon frame, and antenna B3 and antenna B4 can receive the beacon frame and the echo signal generated by the beacon frame being scattered or reflected by the environment. FIG3 illustrates an example in which RF circuit 321 and RF circuit 322 each include two channels. RF circuit 321 and RF circuit 322 can also include one, three, or more channels. Accordingly, RF circuit 321 and RF circuit 322 can be connected to one, three, or more antennas. When AP 100 performs environmental sensing, baseband circuit 311 can enable one or more antennas connected to RF circuit 321 to serve as transmitting antennas, and baseband circuit 312 can enable one or more antennas connected to RF circuit 322 to serve as receiving antennas. Alternatively, baseband circuit 311 can enable one or more antennas connected to RF circuit 321 to serve as receiving antennas, and baseband circuit 312 can enable one or more antennas connected to RF circuit 322 to serve as transmitting antennas. This is sufficient as long as there is a transmitting antenna among the antennas connected to baseband circuit 311 through RF circuit 321 and a receiving antenna among the antennas connected to baseband circuit 312 through RF circuit 322.

[0055] The following is an example of the method flow of the embodiment of the present application.

[0056] The wireless sensing method provided in the embodiments of the present application can be applied to an AP in a WLAN, where the AP includes multiple antennas. For example, the AP can be AP 100 as shown in any of Figures 1 to 3 . For example, Figure 4 is a flow chart of a wireless sensing method provided in the embodiments of the present application. As shown in Figure 4 , the method includes but is not limited to the following steps 401 to 403.

[0057] Step 401: The AP sends a beacon frame using a first antenna.

[0058] Optionally, the AP uses the first antenna to periodically send beacon frames to announce the existence of the WLAN, so that the STA can access the WLAN.

[0059] Optionally, the working channel of the AP is a large bandwidth channel, including a primary channel and a secondary channel. When the working channel of the AP is a large bandwidth channel, beacon frames are generally sent only on the primary channel. In order to improve the perception accuracy, the AP can use the first antenna to send beacon frames on the primary channel and the secondary channel simultaneously. For example, if the bandwidth of the working channel of the AP is 80MHz, including a 20MHz primary channel and three 20MHz secondary channels, the AP can copy the beacon frame transmitted on the primary channel to one or more secondary channels (such as all secondary channels) and transmit them simultaneously, so that the beacon frame is transmitted on a larger bandwidth, so that the AP can receive the echo signal obtained by the reflection or scattering of the beacon frame through the environment on a larger bandwidth, thereby improving the perception accuracy. The larger the bandwidth of the received signal, the higher the perception accuracy. Specifically, the larger the bandwidth of the received signal, the higher the time resolution of the AP for the received signal in the time domain, and the greater the number of subcarriers of the received signal obtained in the frequency domain. Taking the time domain as an example, the propagation time of the echo signal in the medium can reflect the distance between the perceived target and the AP. Therefore, the higher the time resolution of the received signal, the more accurate the calculated distance between the perceived target and the AP, thereby improving the positioning accuracy of the perceived target, that is, improving the perception accuracy.

[0060] Optionally, the AP can also reduce the beacon frame sending time interval during the environmental perception process, that is, the AP sends more beacon frames during the environmental perception process so that the AP can receive more echo signals obtained by the reflection or scattering of the beacon frames through the environment, thereby obtaining more environmental perception information to improve the perception accuracy.

[0061] Step 402: The AP receives an echo signal using the second antenna. The echo signal is obtained by reflecting or scattering the beacon frame sent by the AP using the first antenna.

[0062] It is worth noting that the first antenna in the embodiment of the present application is used to refer to the antenna used by the AP to send beacon frames, and does not specifically refer to a certain antenna of the AP. The first antenna can be one antenna of the AP, or it can be multiple antennas of the AP. The embodiment of the present application does not limit the number of antennas used by the AP to send beacon frames. Similarly, the second antenna in the embodiment of the present application is used to refer to the antenna used by the AP to receive the echo signal obtained by reflection or scattering of the beacon frame, and does not specifically refer to a certain antenna of the AP. The second antenna can be one antenna of the AP, or it can be multiple antennas of the AP. The embodiment of the present application does not limit the number of antennas used by the AP to receive the echo signal.

[0063] Optionally, before sending a beacon frame using the first antenna (i.e., before executing step 401), the AP sets the first antenna as a transmitting antenna and the second antenna as a receiving antenna to wait for receiving an echo signal obtained by reflection or scattering of the beacon frame sent by the first antenna.

[0064] The embodiment of the present application is described by taking the first antenna and the second antenna as different antennas of an AP as an example.

[0065] In one possible implementation, the first antenna and the second antenna are different antennas connected to the same baseband circuit of the AP. For example, as shown in the AP structure in Figure 2, the first antenna may be antenna A1, and the second antenna may be antenna A2. The first and second antennas are connected to the same baseband circuit 21 via radio frequency circuit 22. AP 100 can use antenna A1 to transmit beacon frames and use antenna A2 to receive echo signals.

[0066] In this implementation, the AP can be configured with a communication mode and a sensing mode. When the AP is in communication mode, the transmit and receive states of all antennas connected to the same baseband circuit are typically the same. For example, all antennas are enabled as transmit antennas to transmit signals generated by the baseband circuit, or all antennas are enabled as receive antennas to receive external signals. This improves the AP's signal transmission and reception efficiency. When the AP is in sensing mode, the multiple antennas connected to the same baseband circuit include transmit antennas and receive antennas. This allows the signals sent by the AP's transmit antennas to be received by the receive antennas, thereby achieving environmental awareness.

[0067] Optionally, the AP can perform environmental sensing periodically, for example, every five minutes. Alternatively, the AP can perform environmental sensing in response to a sensing instruction, which can be manually triggered on the AP or sent to the AP by a control instruction from another device. When the AP begins environmental sensing, it can switch from communication mode to sensing mode. Similarly, when the AP completes environmental sensing, it can immediately switch from sensing mode to communication mode, improving communication efficiency.

[0068] In this implementation, because the first and second antennas are connected to the same baseband circuit of the AP via the same RF circuit, a common local oscillator design is achieved for the transmitting and receiving circuits. This ensures that the sampling frequency and carrier frequency between the transmitting and receiving ends are consistent, eliminating the problem of sampling frequency offset and carrier frequency offset affecting the CSI quality of the received signal, thereby improving environmental perception accuracy. Furthermore, internal time synchronization is no longer required, thereby improving environmental perception efficiency.

[0069] In another possible implementation, the first antenna and the second antenna are connected to different baseband circuits of the AP. Optionally, the first antenna is connected to the first baseband circuit of the AP via a first radio frequency circuit, and the second antenna is connected to the second baseband circuit of the AP via a second radio frequency circuit. For example, as shown in the AP structure in Figure 3, the first antenna may be antenna B1 and antenna B2, and the second antenna may be antenna B3 and antenna B4. The first radio frequency circuit may be radio frequency circuit 321, and the first baseband circuit may be baseband circuit 311, that is, the first antenna (antenna B1 and antenna B2) is connected to baseband circuit 311 via radio frequency circuit 321. The second radio frequency circuit may be radio frequency circuit 322, and the second baseband circuit may be baseband circuit 312, that is, the second antenna (antenna B3 and antenna B4) is connected to baseband circuit 312 via radio frequency circuit 322. AP 100 can use antenna B1 and antenna B2 to transmit beacon frames, and use antenna B3 and antenna B4 to receive echo signals.

[0070] Optionally, when the operating frequencies of the first RF circuit and the second RF circuit are different, before the AP sends a beacon frame using the first antenna (i.e., before executing step 401), it is necessary to switch the operating frequencies of the first RF circuit and / or the second RF circuit so that the operating frequencies of the first RF circuit and the second RF circuit are the same. For example, if the operating frequency of the first RF circuit is 5.2 GHz and the operating frequency of the second RF circuit is 5.4 GHz, the operating frequency of the second RF circuit can be switched from 5.4 GHz to 5.2 GHz, or the operating frequency of the first RF circuit can be switched from 5.2 GHz to 5.4 GHz, so that the first RF circuit and the second RF circuit operate at the same frequency, thereby enabling the signal sent by the first antenna to be received by the second antenna.

[0071] Optionally, the AP can perform environmental sensing periodically, for example, every 5 minutes. Alternatively, the AP can perform environmental sensing when triggered by a sensing instruction, which can be manually triggered on the AP or a control instruction sent to the AP by another device. When the AP starts environmental sensing, the first RF circuit and the second RF circuit can be switched to the same operating frequency. Accordingly, when the AP ends environmental sensing, the operating frequencies of the first RF circuit and the second RF circuit can be immediately restored to the original operating frequencies to minimize the impact on the normal communication of the AP.

[0072] The embodiments of the present application do not exclude the possibility that the first antenna and the second antenna are the same antenna. In this implementation, after the AP sends the beacon frame using the first antenna, it can immediately switch the first antenna from a transmitting antenna to a receiving antenna to wait for the echo signal obtained by reflection or scattering of the sent beacon frame.

[0073] In addition to using the second antenna to receive echo signals, the AP also uses the second antenna to receive beacon frames sent directly from the first antenna (called direct signals). Because signals take time to propagate through the air, and the propagation distance of direct signals is much shorter than that of echo signals, the first beacon frame received by the AP using the second antenna is the direct signal, while the second beacon frame received by the AP using the second antenna is the echo signal.

[0074] Furthermore, after the AP receives the echo signal using the second antenna, the following step 403 is executed.

[0075] Step 403: The AP performs environment perception based on the received echo signal.

[0076] Optionally, the AP can perform environmental awareness based on the frequency domain characteristics of the received echo signal. For example, the AP can perform frequency domain sampling on the received echo signal to calculate the CSI, and then perform environmental awareness based on the CSI. In this implementation, the AP can reuse the communication processing link to calculate the CSI of the received signal.

[0077] Optionally, the AP performs environmental perception based on CSI. The AP may collect CSI of the echo signal received over a period of time, and then perceive changes in the environment based on changes in the amplitude information and / or phase information of the CSI during this period. For example, continuous CSI data collected over a period of time may be analyzed in a model-based or learning-based manner to perceive the environment. Taking the pattern-based method for determining whether there is human intrusion in the environment as an example, training samples may be collected in advance, and a machine learning model may be trained using a supervised learning method to obtain an intrusion detection model. The training samples include the amplitude information and phase information of the CSI of the echo signal collected by the AP when there is no human intrusion in the environment, and the amplitude information and phase information of the CSI of the echo signal collected by the AP when there is human intrusion in the environment. When the AP performs environmental perception, the amplitude information and phase information of the CSI of the collected echo signal may be used as input to the intrusion detection model to obtain a judgment result output by the intrusion detection model, which indicates whether there is human intrusion in the environment or not.

[0078] Alternatively, the AP performs environmental perception based on CSI. Alternatively, the AP collects CSI of echo signals received over a period of time and then uploads the collected CSI to a wireless controller or server. The wireless controller or server then perceives environmental changes based on changes in the amplitude and / or phase information of the CSI over this period of time.

[0079] When receiving an echo signal, the AP needs to adjust the received signal power gain of the echo signal. If the received signal power of the echo signal is too low, the AP needs to amplify it. If the received signal power of the echo signal is too high, the AP needs to attenuate it. This ultimately adjusts the received signal power of the echo signal to an appropriate level, enabling the AP to successfully receive the echo signal. The entire process by which the AP adjusts the received signal power gain of the echo signal is known as the AGC adjustment process. AGC adjustment is primarily implemented by the AGC module, the control interface, and the analog amplifier. The AGC module is typically located in the baseband circuit, while the analog amplifier is located in the RF circuit. The control interface bridges the baseband and RF circuits, transmitting control signals between them. In specific implementation, the AGC module calculates the received signal power adjustment method and sends a power adjustment control word to the analog amplifier via the control interface. The analog amplifier then adjusts the AGC level based on the power adjustment control word to achieve gain adjustment of the received signal power.

[0080] Because the transmit and receive power of AP signals can vary with the environment, the AP may switch AGC levels to receive signals during operation. For the same received signal, different AGC levels result in different calculated CSI values. Based on this, embodiments of the present application provide a method for compensating CSI data to minimize the impact of the dynamic CSI variation introduced by the AGC level on environmental perception.

[0081] Optionally, the AP can perform amplitude and phase compensation on the CSI based on a preset amplitude and phase compensation relationship and the AGC level corresponding to the echo signal. This amplitude and phase compensation relationship includes amplitude compensation values ​​and / or phase compensation values ​​corresponding to multiple AGC levels. The AP then performs environmental perception based on the amplitude and phase compensated CSI. The amplitude and phase compensation relationship can be established by controlling the AP's transmit power and the AGC level corresponding to the received signal. When the environment contains a large number of data packets, the AGC level may vary significantly. By performing CSI data compensation, perception accuracy can be improved.

[0082] For example, the RF circuit connected to the second antenna has 10 AGC levels. The transmit power of the first antenna can be fixed. Different AGC levels in the RF circuit are then used to process the signal transmitted by the first antenna and received by the second antenna. The amplitude and phase of the CSI of the received signal are calculated. Using one of the AGC levels as a reference, the difference between the amplitude and phase of the CSI of the received signal at the other AGC levels and the amplitude and phase of the CSI of the received signal at the reference AGC level is calculated, and the difference is used as the amplitude compensation value and the phase compensation value. After receiving the echo signal using the second antenna, the AP can obtain the amplitude compensation value and the phase compensation value based on the AGC level corresponding to the echo signal to perform amplitude and phase compensation on the CSI of the echo signal.

[0083] Alternatively, when the AP is performing environmental perception, the power gain of the received signal of the second antenna is set to a fixed value, that is, a fixed AGC gear position, to improve perception accuracy.

[0084] In an embodiment of the present application, by performing amplitude and phase compensation on the CSI data of the received signal, or fixing the AGC gear of the received signal, the CSI variables introduced by the hardware channel can be reduced or avoided, thereby improving the accuracy of environmental perception.

[0085] Optionally, the AP may also perform environmental perception based on the time domain characteristic information of the received echo signal. For example, the AP may perform time domain in-phase quadrature (IQ) sampling on the received echo signal and perform cross-correlation and other operations on the sampling results to perform environmental perception. The embodiments of the present application will not be described in detail here.

[0086] In the wireless sensing method provided in the embodiment of the present application, the AP uses the first antenna to send a beacon frame, and uses the second antenna to receive the echo signal obtained by reflecting or scattering the beacon frame, and further performs environmental perception based on the received echo signal. The embodiment of the present application utilizes the ability of the AP to send and receive messages by itself. The same AP sends a beacon frame and receives the echo signal of the beacon frame. Compared with the AP, the signal sending and receiving location is always known, which helps to improve the accuracy of environmental perception. The deployment location of the AP is not restricted and can be flexibly applied to various scenarios, which can improve the robustness of the perception algorithm to environmental changes. In addition, the AP uses beacon frames to achieve environmental perception. Beacon frames are sent periodically to announce the presence of the AP. Therefore, the use of beacon frames to achieve environmental perception does not require additional packet transmission, which can save channel resources, and can complete environmental perception during normal communication, realizing integrated communication and perception.

[0087] The sequence of steps in the wireless sensing method provided in the embodiments of the present application can be adjusted appropriately, and the number of steps can be increased or decreased according to the circumstances. Any method that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application.

[0088] For example, in the solution of the present application, in addition to using beacon frames to achieve environmental perception, the AP can also use data frames, control frames, other management frames or private frames other than beacon frames to achieve environmental perception. The specific implementation method can refer to the method of using beacon frames to achieve environmental perception described in the above embodiment.

[0089] Optionally, the AP uses data frames for environmental awareness. Specifically, the AP transmits data frames using its first antenna and receives echo signals from the data frames, which are reflected or scattered, using its second antenna. The AP then performs environmental awareness based on the echo signals from the data frames. With this approach, when the AP is busy, it can collect more echo signals, thereby obtaining sufficient environmental awareness information and improving awareness accuracy.

[0090] Alternatively, the AP can use a combination of data frames and beacon frames for environmental awareness. For example, when the AP is busy, the AP uses only data frames for environmental awareness. When the AP is less busy, the AP can use both data frames and beacon frames for environmental awareness. For example, the AP can increase the beacon frame transmission frequency and / or increase the beacon frame transmission bandwidth to enable the AP to receive more echo signals from beacon frames reflected or scattered by the environment, thereby obtaining more environmental awareness information and improving perception accuracy.

[0091] The following describes the virtual device in the embodiment of the present application by way of example.

[0092] The present invention provides an AP in a WLAN. For example, FIG5 is a schematic diagram of the structure of an AP provided in the present invention. As shown in FIG5 , AP 500 includes a sending module 501, a receiving module 502, and a processing module 503.

[0093] The sending module 501 is configured to send a beacon frame using the first antenna. The specific implementation process of the sending module 501 may refer to the above step 401.

[0094] The receiving module 502 is configured to use the second antenna to receive an echo signal, which is obtained by reflecting or scattering the beacon frame. The specific implementation process of the receiving module 502 can refer to the above step 402.

[0095] The processing module 503 is used to perform environmental perception based on the received echo signal. The specific implementation process of the processing module 503 can refer to the above step 403.

[0096] Optionally, the first antenna and the second antenna are different antennas connected to the same baseband circuit of the AP.

[0097] Optionally, the first antenna and the second antenna are respectively connected to different baseband circuits of the AP.

[0098] Optionally, the sending module 501 is specifically configured to: use the first antenna to simultaneously send a beacon frame on the primary channel and the secondary channel.

[0099] Optionally, the processing module 503 is specifically used to: calculate the CSI based on the received echo signal; based on a preset amplitude-phase compensation relationship, perform amplitude-phase compensation on the CSI according to the AGC gear corresponding to the echo signal, the amplitude-phase compensation relationship including amplitude compensation values ​​and / or phase compensation values ​​corresponding to multiple AGC gears; and perform environmental perception based on the CSI after amplitude-phase compensation.

[0100] Regarding the apparatus in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0101] An embodiment of the present application further provides an AP, comprising: a processor, a memory, a transceiver, and multiple antennas.

[0102] A transceiver is configured to transmit a beacon frame using a first antenna among a plurality of antennas.

[0103] The transceiver is further configured to use a second antenna among the multiple antennas to receive an echo signal, where the echo signal is obtained by reflection or scattering of the beacon frame.

[0104] The processor is configured to call a computer program stored in the memory to perform environmental perception based on the received echo signal.

[0105] Optionally, the transceiver is specifically configured to use the first antenna to simultaneously send beacon frames on the primary channel and the secondary channel.

[0106] Optionally, the processor is specifically used to call a computer program stored in the memory to calculate the CSI based on the received echo signal; based on a preset amplitude-phase compensation relationship, perform amplitude-phase compensation on the CSI according to the AGC gear corresponding to the echo signal, and the amplitude-phase compensation relationship includes amplitude compensation values ​​and / or phase compensation values ​​corresponding to multiple AGC gears; and perform environmental perception based on the CSI after amplitude-phase compensation.

[0107] For example, the AP may be AP 100 as shown in Figure 2 or Figure 3. The computer program stored in memory 102 may include one or more software modules. These one or more software modules may be the software modules provided in the embodiment shown in Figure 5. Processor 101 is configured to call the computer program and cooperate with transceiver 103 to implement the wireless sensing method provided in the above method embodiment. Transceiver 103 is configured to perform the transceiver actions of the AP in the above method embodiment. Optionally, memory 102 is further configured to store amplitude compensation values ​​and / or phase compensation values ​​corresponding to multiple AGC gears of transceiver 103 for use by processor 101.

[0108] An embodiment of the present application further provides a computer-readable storage medium having instructions stored thereon. When the instructions are executed by a processor, the wireless sensing method involved in the above method embodiment is implemented.

[0109] Those skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware, or by a program to instruct the relevant hardware, and the program may be stored in a computer-readable storage medium, which may be a read-only memory, a disk, or an optical disk, etc.

[0110] In the embodiments of the present application, the terms “first”, “second” and “third” are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0111] In this application, the term "and / or" simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0112] It should be noted that the information (including but not limited to user device information, user personal information, etc.), data (including but not limited to data used for analysis, stored data, displayed data, etc.) and signals involved in this application are all authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of relevant countries and regions.

[0113] The above description is merely an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the concepts and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A wireless sensing method, characterized in that: The method comprises: An access point AP in a wireless local area network WLAN sends a beacon frame using a first antenna; The AP receives an echo signal using a second antenna, where the echo signal is obtained by reflecting or scattering the beacon frame; The AP performs environment perception according to the received echo signal.

2. The method according to claim 1, characterized in that: The first antenna and the second antenna are different antennas connected to the same baseband circuit of the AP.

3. The method according to claim 1, characterized in that The first antenna and the second antenna are respectively connected to different baseband circuits of the AP.

4. The method according to any one of claims 1 to 3, characterized in that: The AP sends a beacon frame using a first antenna, including: The AP transmits the beacon frame simultaneously on a primary channel and a secondary channel using the first antenna.

5. The method according to any one of claims 1 to 4, characterized in that: The AP performs environment perception according to the received echo signal, including: The AP calculates channel state information CSI according to the received echo signal; The AP performs amplitude and phase compensation on the CSI based on a preset amplitude and phase compensation relationship and according to an automatic gain control AGC gear corresponding to the echo signal, wherein the amplitude and phase compensation relationship includes amplitude compensation values ​​and / or phase compensation values ​​corresponding to multiple AGC gears; The AP performs environment perception according to the CSI after amplitude and phase compensation.

6. An access point AP in a wireless local area network WLAN, characterized in that: include: A sending module, configured to send a beacon frame using a first antenna; A receiving module, configured to receive an echo signal using a second antenna, wherein the echo signal is obtained by reflecting or scattering the beacon frame; A processing module is used to perform environmental perception according to the received echo signal.

7. The AP according to claim 6, characterized in that: The first antenna and the second antenna are different antennas connected to the same baseband circuit of the AP.

8. The AP according to claim 6, characterized in that: The first antenna and the second antenna are respectively connected to different baseband circuits of the AP.

9. The AP according to any one of claims 6 to 8, characterized in that: The sending module is used for: The beacon frame is transmitted simultaneously on a primary channel and a secondary channel using the first antenna.

10. The AP according to any one of claims 6 to 9, characterized in that: The processing module is used to: Calculating channel state information CSI according to the received echo signal; Based on a preset amplitude-phase compensation relationship, performing amplitude-phase compensation on the CSI according to an automatic gain control AGC gear corresponding to the echo signal, the amplitude-phase compensation relationship including amplitude compensation values ​​and / or phase compensation values ​​corresponding to a plurality of AGC gears; Environmental perception is performed based on the CSI after amplitude and phase compensation.

11. An access point AP in a wireless local area network WLAN, characterized in that: include: processor, memory, transceiver, and multiple antennas; The transceiver is configured to send a beacon frame using a first antenna among the multiple antennas; The transceiver is further configured to receive an echo signal using a second antenna among the plurality of antennas, wherein the echo signal is received by the beacon frame after being reflected obtained by radiation or scattering; The processor is used to call the computer program stored in the memory to perform environmental perception according to the received echo signal.

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