Wi-fi based environment perception method and wi-fi device for environment perception

Abstract

Disclosed in the present invention is a Wi-Fi based environment perception method, for use in monitoring a spatial region. The method comprises: a perception initiation device sending at least one first fine time measurement frame to a perception response device; the perception initiation device receiving at least one first fine time response frame sent by the perception response device; determining a first timing measurement result between the perception initiation device and the perception response device on the basis of the at least one first fine time measurement frame and the at least one first fine time response frame; and determining state change information in the spatial region on the basis of whether a difference between the first timing measurement result and a first initial timing measurement result exceeds a threshold. The present invention can realize non-contact environment perception and monitoring functions, and solves the problem in the prior art of unstable and unreliable perception results caused by influence of channel changes.

Description

A Wi-Fi-based environment perception method and a Wi-Fi device for environment perception Technical Field

[0001] The present invention relates to wireless perception, and more particularly, to a Wi-Fi-based environment perception method and a Wi-Fi device for environment perception. Background Art

[0002] In addition to being used for data communication, wireless signals (such as 5G and Wi-Fi) can also be used to sense the environment and the location and status of people. Technologies that use wireless signals to sense the location and status of people are generally referred to as wireless sensing technologies. Wireless sensing technologies enable contactless monitoring and positioning, offering advantages such as low cost, high coverage, and ease of use.

[0003] Common outdoor wireless sensing technologies include outdoor satellite navigation systems (such as GPS and Beidou) and indoor wireless positioning technologies (such as Wi-Fi, UWB, Bluetooth, and Zigbee). Wi-Fi-based wireless sensing, also known as "Wi-Fi sensing," uses wireless local area network (WLAN) signals to sense the environment, specifically the location and status of objects and people. Wi-Fi sensing can leverage existing Wi-Fi devices and networks, requiring no additional hardware or spectrum resources.

[0004] Typical Wi-Fi sensing methods are based on Channel State Information (CSI) or Received Signal Strength Indication (RSSI). Their fundamental principle is to estimate changes in objects in the environment by analyzing factors such as obstacle scattering, fading, energy attenuation, and distance attenuation as the signal travels from the transmitter to the receiver. Based on this information, Wi-Fi sensing can be used in a variety of applications, such as people counting, behavior recognition, security monitoring, and respiratory monitoring.

[0005] However, both RSSI-based and CSI-based Wi-Fi sensing have drawbacks. For example, because RSSI cannot distinguish different propagation paths and channel characteristics, small-scale shadow fading caused by multipath propagation can cause RSSI-based Wi-Fi sensing to no longer decrease monotonically with distance, limiting ranging accuracy. Furthermore, multipath propagation can cause RSSI amplitude fluctuations, impacting the stability and reliability of wireless sensing results. While CSI-based Wi-Fi sensing can provide more detailed channel information, it is also sensitive to channel environments and conditions. For example, environmental noise, multipath effects, and device errors can lead to unstable CSI data quality, requiring complex preprocessing and calibration. For example, in scenarios with dense crowds or frequent object movement, CSI can experience significant fluctuations, resulting in errors in location estimation and people counting.

[0006] Therefore, a new technical solution is needed in this field, which can overcome the multipath effect, signal attenuation or other interference effects to improve the accuracy and robustness of wireless sensing results.

[0007] It should be understood that the above-mentioned technical problems are merely examples and are not intended to limit the present invention. In addition, the present invention is not limited to technical solutions that simultaneously solve all of the above-mentioned technical problems. The technical solution of the present invention can be implemented to solve one or more of the above-mentioned or other technical problems.

[0008] Summary of the Invention

[0009] The present invention aims to address existing issues in Wi-Fi-based environmental sensing. CSI- or RSSI-based environmental sensing is sensitive to channel conditions and easily affected by multipath effects, signal attenuation, signal interference, or other wireless channel variations, resulting in unstable and unreliable sensing results.

[0010] To address the shortcomings of existing solutions, this paper proposes a Wi-Fi-based environmental sensing technology that can be used to monitor changes in objects and people within an environment. Leveraging the high precision and robustness of FTM technology, this paper effectively measures the distance between Wi-Fi devices using signals between them, thereby enabling contactless sensing and monitoring.

[0011] In a first aspect of the present invention, a Wi-Fi-based environment perception method for monitoring a spatial region is provided. The method includes: sending at least one first fine time measurement frame from a perception initiating device to a perception responding device; receiving, by the perception initiating device, at least one first fine time response frame sent by the perception responding device; determining, based on the at least one first fine time measurement frame and the at least one first fine time response frame, a first timing measurement result between the perception initiating device and the perception responding device; and determining, based on whether a difference between the first timing measurement result and a first initial timing measurement result exceeds a threshold, state change information in the spatial region.

[0012] Optionally, the state change information of the spatial region indicates whether an object or a person moves in the spatial region.

[0013] Optionally, in response to the state change information indicating that an object or person has moved in the spatial area, the method also includes: sending at least one second fine time measurement frame from the perception initiating device to the perception responding device; the perception initiating device receiving at least one second fine time response frame sent by the perception responding device; determining a second timing measurement result between the perception initiating device and the perception responding device based on the at least one second fine time measurement frame and the at least one second fine time response frame; and determining size information of the object or person moving in the spatial area based on the second timing measurement result and at least one second initial timing measurement result.

[0014] Optionally, determining a first timing measurement result between a perception initiating device and a perception responding device includes: filtering multiple timing measurement results obtained based on multiple first fine time measurement frames and multiple first fine time response frames to obtain filtered values ​​of the multiple timing measurement results, and using the filtered values ​​as the first fine timing measurement result.

[0015] Optionally, determining the second timing measurement result between the perception initiating device and the perception responding device includes: filtering multiple timing measurement results obtained based on multiple second fine time measurement frames and multiple second fine time response frames to obtain filtered values ​​of the multiple timing measurement results, and using the filtered values ​​as the second fine timing measurement result.

[0016] Optionally, in response to determining that the difference between the first timing measurement result and the first initial timing measurement result exceeds a threshold value for a consecutive predetermined number of times and / or within a consecutive predetermined time, the first initial timing measurement result is remeasured and updated.

[0017] Optionally, in response to determining the first timing measurement result and / or the second timing measurement result, the first timing measurement result and / or the second timing measurement result are synchronized to one or more Wi-Fi devices in the same network as the perception initiating device and / or the perception responding device.

[0018] Optionally, the perception initiating device and the perception responding device are deployed such that a signal propagation path between the perception initiating device and the perception responding device passes through the spatial region, preferably, passes through the center of the spatial region.

[0019] In a second aspect of the present invention, a Wi-Fi device for environmental awareness is provided, which is configured to monitor a spatial area. The Wi-Fi device includes: a processor; a memory; and a transceiver operating in conjunction with the processor. The memory stores computer instructions that, when executed by the processor, cause the Wi-Fi device to perform the following steps: enter a configuration mode and scan for host devices within a predetermined range; in response to not scanning for a host device within a specified time, configure the Wi-Fi device to a host state and establish a connection with a second Wi-Fi device; or, in response to scanning for a host device within a specified time, configure the Wi-Fi device to a slave state and establish a connection with the scanned host device; and, in response to receiving a mode switch command, enter an operating mode, with the Wi-Fi device acting as one of a sensing initiator and a sensing responder, and the second Wi-Fi device or the host device acting as the other of the sensing initiator and the sensing responder, to perform any of the methods described above.

[0020] Optionally, the Wi-Fi device receives a designated transceiver sequence, the designated transceiver sequence including parameters indicating an initiation time slot and a response time slot of the Wi-Fi device. Furthermore, the Wi-Fi device entering the operational mode further includes: determining an initiation time slot and a response time slot of the Wi-Fi device based on the designated transceiver sequence; during the initiation time slot, the Wi-Fi device acts as a sensing initiator and executes any of the methods described above; and during the response time slot, the Wi-Fi device acts as a sensing responder and executes any of the methods described above.

[0021] In a third aspect of the present invention, a Wi-Fi-based environmental perception system is provided for monitoring a spatial area. The environmental perception system includes a first device and a second device, wherein the first device and the second device respectively include at least one transmitting antenna and at least one receiving antenna. The first device acts as a perception initiating device, and the second device acts as a perception responding device, and executes any of the methods described above to monitor a first spatial area between the first device and the second device.

[0022] Optionally, the environmental perception system also includes a third device, wherein the third device includes at least one transmitting antenna and at least one receiving antenna; wherein the second device acts as a perception initiating device and the third device acts as a perception responding device to execute any one of the methods described above to monitor a second spatial area between the second device and the third device.

[0023] Further optionally, the third device acts as a perception initiating device and the first device acts as a perception responding device to execute any one of the methods described above to monitor a third spatial area between the third device and the first device.

[0024] Optionally, each of the first device, the second device and the third device respectively receives its own designated transceiver sequence, and the designated transceiver sequence indicates an initiation time slot and a response time slot; each of the first device, the second device and the third device respectively acts as a perception initiation device during the initiation time slot indicated by its own designated transceiver sequence to execute any one of the methods described above, and each of the first device, the second device and the third device respectively acts as a perception response device during the response time slot indicated by its own designated transceiver sequence to execute any one of the methods described above.

[0025] Optionally, the first device and the second device are deployed so that the signal propagation path between the first device and the second device passes through the first spatial region, preferably, through the center of the spatial region; the second device and the third device are deployed so that the signal propagation path between the second device and the third device passes through the second spatial region, preferably, through the center of the spatial region; and the third device and the first device are deployed so that the signal propagation path between the third device and the first device passes through the third spatial region, preferably, through the center of the spatial region.

[0026] In a fourth aspect of the present invention, a computer-readable storage medium is provided, on which instructions for environmental perception are stored, wherein when the instructions are executed by one or more processors, the one or more processors execute any one of the methods described above.

[0027] This invention effectively avoids unstable environmental perception results caused by multipath effects, signal attenuation, and signal interference. This solution uses the FTM protocol for environmental perception, resulting in low false alarm rates and high robustness. Furthermore, the method of the present invention enables simultaneous monitoring of multiple spatial regions. The environmental perception method of the present invention can be applied to scenarios such as vehicle detection and security monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG1 shows a schematic diagram of the working principle of timing measurement according to the FTM protocol;

[0029] FIG2 is a schematic diagram showing a flow chart of a Wi-Fi-based environment perception method according to an embodiment of the present invention;

[0030] FIG3 shows a schematic diagram of a Wi-Fi device for environment awareness according to an embodiment of the present invention;

[0031] FIG4 shows a flowchart of a Wi-Fi device in a configuration mode according to an embodiment of the present invention;

[0032] FIG5 shows a flowchart of a Wi-Fi device in operation mode according to an embodiment of the present invention;

[0033] FIG6 shows an example diagram of a Wi-Fi-based environment perception system according to an embodiment of the present invention;

[0034] FIG7 shows a schematic diagram of an application scenario according to a specific embodiment of the present invention;

[0035] FIG8 shows a schematic diagram of another application scenario according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0036] The method of the present invention utilizes the FTM protocol for environmental perception, and is used to monitor changes in objects or people within an area. The method of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments shown in the drawings and described below are merely illustrative and are not intended to limit the present invention.

[0037] The Wi-Fi protocol introduced the Fine Time Measurement (FTM) protocol in the IEEE 802.11mc standard in 2016. FTM uses the round-trip time (RTT) or arrival time of data packets between communicating devices and their propagation speed to calculate the distance between them. This can be used to improve indoor positioning accuracy, achieving centimeter-level positioning.

[0038] FIG1 shows a schematic diagram of the working principle of performing timing measurement to measure distance according to the FTM protocol, wherein the AP (a wireless access point device is used as an example in the figure) serves as the initiating device, and the STA (a mobile phone terminal is used as an example in the figure) serves as the responding device.

[0039] As shown in Figure 1, a STA first sends an FTM request to the AP. After receiving the FTM request, the AP responds with an FTM acknowledgment. Next, at time t1, the AP sends an FTM measurement frame to the STA. The STA receives the FTM measurement frame at time t2 and then sends an FTM response frame to the AP at time t3. At time t4, the AP receives the response frame from the STA.

[0040] Since the time between the AP and the STA cannot be synchronized at the nanosecond level, the difference in the timestamps between the transmitter and the receiver of a one-way signal cannot accurately reflect the signal propagation time. Therefore, the principle of two-way unilateral ranging is usually used to measure the round-trip time between the AP and the STA. Specifically, according to the principle of two-way unilateral ranging, the distance between the AP and the STA can be given by the following formula, where c is the speed of light in a given medium (in meters per second): 2*D=((t4-t1)-(t3-t2))*c

[0041] Furthermore, in order to eliminate the influence of error factors such as clock deviation and hardware delay, in actual applications, multiple measurements can be used to reduce measurement errors. For example, within a period of time T, the AP sends FTM measurement frames and receives corresponding FTM response frames N times in succession, thereby obtaining multiple measurement results D1, D2, ...D N The final measurement result is obtained by averaging or filtering the measurement results obtained by N measurements.

[0042] Conventional technology uses the attenuation of CSI or RSSI signals to calculate the distance between two communicating devices. However, this method is limited by the channel environment and is susceptible to multipath effects and signal attenuation, resulting in unstable measurement results. The present invention addresses this issue by using the FTM protocol to calculate the round-trip time of signals between the transmitter and receiver, avoiding multipath effects. This allows for more accurate distance measurement and can be further applied to environmental sensing.

[0043] This application applies the FTM protocol to the field of environmental perception. Leveraging the FTM protocol's high-precision timing measurement technology, it enables real-time monitoring of changes in objects or people within an area, improving the efficiency and accuracy of environmental perception. This application also creatively designs a working sequence to schedule the transmission and reception actions of each communication device, enabling simultaneous or alternating perception of multiple monitoring areas, avoiding signal interference and conflict, and improving system reliability and stability.

[0044] Example 1

[0045] As shown in FIG2 , the present invention provides a flow chart of a Wi-Fi-based environment perception method according to an embodiment of the present invention. The method is used to monitor a spatial area, including the following steps:

[0046] Step 202: Send at least one first fine time measurement frame from the sensing initiating device to the sensing responding device.

[0047] Step 204: The sensing initiating device receives at least one first fine time response frame sent by the sensing responding device.

[0048] Step 206: Determine a first timing measurement result between the perception initiating device and the perception responding device according to the at least one first fine time measurement frame and the at least one first fine time response frame.

[0049] Step 208: Determine the state change information in the spatial area according to whether the difference between the first time series measurement result and the first initial time series measurement result exceeds a threshold.

[0050] The timing measurement result may be the round-trip time (RTT) or arrival time between the communication devices obtained based on the FTM protocol data packet. In some embodiments, the timing measurement result may also be the distance between the communication devices calculated based on the round-trip time (RTT) or arrival time between the communication devices obtained based on the FTM protocol data packet and the propagation speed of light in the medium of the corresponding spatial region.

[0051] As an example and not a limitation, the state change information of the spatial region indicates whether an object or a person moves in the spatial region.

[0052] As an example and not a limitation, determining a first timing measurement result between a perception initiating device and a perception responding device includes: filtering a plurality of timing measurement results obtained based on a plurality of first fine time measurement frames and a plurality of first fine time response frames to obtain filtered values ​​of the plurality of timing measurement results, and using the filtered values ​​as the first fine timing measurement result. A filtering operation is a method for processing timing measurement results, and different filtering algorithms may be selected according to different purposes and requirements. For example, Gaussian filtering is a smoothing operation that can reduce noise and fluctuations in measurement results; mean filtering is an operation for averaging values ​​that can reflect the overall level of measurement results; median filtering is an operation for removing extreme values ​​that can eliminate abnormal points in measurement results; and adaptive filtering is an operation for dynamically adjusting parameters based on measurement results that can adapt to different scenarios and conditions.

[0053] In order to monitor a spatial region and determine changes in the state of the spatial region, it is necessary to first determine a first initial time series measurement result as a basis for subsequent measurements and judgments. In some specific embodiments, the first initial time series measurement result can be a measurement result when the monitored spatial region is an empty area or in another stable state. Because the environment of the monitored spatial region itself may change, for example, the perception initiator device and the perception response device are moved, the first initial time series measurement result needs to be updated when necessary.

[0054] As an example and not a limitation, in response to determining that the difference between the first timing measurement result and the first initial timing measurement result exceeds a threshold value for a predetermined number of consecutive times and / or within a predetermined time, the first initial timing measurement result is remeasured and updated. In one example, the judgment is made based on whether the difference between the continuous measurement results and the first initial timing measurement result exceeds a threshold value. If, in a predetermined number of consecutive measurements, each measurement result deviates significantly from the first initial timing measurement result, it can be considered that the environment has changed and the first initial timing measurement result needs to be remeasured and updated. In another example, a timer can be set. If, before the timer expires, the difference between any timing measurement result and the first initial timing measurement result exceeds the set threshold value, it can also be considered that the environment has changed and the first initial timing measurement result needs to be remeasured and updated.

[0055] According to another embodiment of the present invention, in response to the state change information determined in step 208 indicating that an object or person moves in the spatial area, the method further includes the following steps:

[0056] Step 210: Send at least one second fine time measurement frame from the sensing initiating device to the sensing responding device.

[0057] Step 212: The sensing initiating device receives at least one second fine time response frame sent by the sensing responding device.

[0058] Step 214: Determine a second timing measurement result between the perception initiating device and the perception responding device according to the at least one second fine time measurement frame and the at least one second fine time response frame.

[0059] Step 216: Determine the size information of the object or person moving in the spatial area based on the second time series measurement result and at least one second initial time series measurement result.

[0060] By way of example and not limitation, determining a second timing measurement result between a perception initiating device and a perception responding device includes filtering a plurality of timing measurement results obtained based on a plurality of second fine time measurement frames and a plurality of second fine time response frames to obtain filtered values ​​of the plurality of timing measurement results, and using the filtered values ​​as the second fine timing measurement result. Similar to the first fine timing measurement result, different filtering algorithms may be selected for the filtering operation on the second fine timing measurement result, such as Gaussian filtering, mean filtering, median filtering, or other filtering algorithms.

[0061] In order to achieve more detailed monitoring of the spatial area, for example, to further determine the size information corresponding to the objects or people moving in the spatial area, such as length, width, etc., the spatial area can be measured multiple times in different scenarios to obtain at least one second initial time series measurement result as a reference for subsequent measurement and judgment. In some specific embodiments, the second initial time series measurement result can reflect a specific change in the monitored spatial area, such as the volume of the moving object. As an example and not a limitation, by comparing or performing a difference operation on the second time series measurement result with at least one second initial time series measurement result and comparing it with a set threshold, the size information corresponding to the objects or people moving in the spatial area, such as length, width, etc. or quantity information, can be further determined. For example, the second initial time series measurement result can correspond to the measurement result when the length of the moving object is 0.5m, 1m, etc., or corresponds to the moving object being a small object (e.g., centimeter-level size), a medium object (e.g., decimeter-level size), or a large object (e.g., meter-level size), to assist in identifying more detailed information of objects or people moving in the spatial area. Those skilled in the art should understand that the threshold values ​​corresponding to small objects, medium objects and large objects can be determined by statistical analysis or machine learning of the measurement results of sample objects of various sizes. It should also be understood that although the sizes of the moving objects mentioned in this example are divided into three categories: small, medium and large, the accuracy of the solution of the present invention for identifying the size of moving objects is not limited to this, and a finer or coarser classification can be adopted according to actual application requirements. For another example, the second initial time series measurement result may correspond to the measurement result when the number of people in the spatial area is one person, two people, etc. When the present invention uses Wi-Fi signals for fine time measurement, it will be affected by objects in space. Establishing initial time series measurement data as a reference benchmark based on multiple initial measurement results can achieve richer measurement effects.

[0062] According to yet another embodiment of the present invention, in response to determining the first timing measurement result in step 206 or determining the second timing measurement result in step 214, the method further includes the following steps:

[0063] Step 218: Synchronize the first timing measurement result and / or the second timing measurement result to one or more Wi-Fi devices in the same network as the sensing initiating device and / or the sensing responding device.

[0064] In some embodiments, the results determined in step 208 or step 216 may also be synchronized to one or more Wi-Fi devices in the same network as the sensing initiating device and / or the sensing responding device. In some embodiments, the data may be uploaded to the server by a Wi-Fi device with the best signal strength within the network. In some embodiments, the network connecting the devices is not limited to a traditional Wi-Fi network and may also be a Wi-Fi MESH, BLE MESH, or other network protocols.

[0065] As an example and not a limitation, in order to further improve the accuracy of environmental perception, an embodiment of the present invention proposes an optimized arrangement, that is, the perception initiating device and the perception responding device are deployed on both sides of the spatial area, so that the signal propagation path between the perception initiating device and the perception responding device passes through the spatial area, preferably, passes through the center of the spatial area. In this way, when there are objects or people in the spatial area, the signal transmission time will be affected to the greatest extent, so that the presence of objects or people can be more easily detected. On the contrary, if the perception initiating device and the perception responding device are too close, the signal transmission time will be affected to a lesser extent, or even may be negligible, resulting in inaccurate environmental perception results. Therefore, an embodiment of the present invention adopts an arrangement to avoid this situation. It is worth noting that the above arrangement is only an example, and the embodiments of the present invention are not limited to this arrangement, but can adopt any other alternative arrangement to achieve the same or similar effects.

[0066] Example 2

[0067] As shown in FIG3 , the present invention provides a schematic diagram of a Wi-Fi device 300 for environment perception according to an embodiment of the present invention, wherein the Wi-Fi device is used to monitor a spatial area and includes: a processor 302; a memory 304; and a transceiver 306 operating in conjunction with the processor; wherein the memory stores computer instructions, and when the computer instructions are executed by the processor, the Wi-Fi device performs the following steps: (1) entering a configuration mode and scanning for a host device within a predetermined range; (2) in response to not scanning for a host device within a specific time, configuring the Wi-Fi device to a host state and establishing a connection with a second Wi-Fi device; or, in response to scanning for a host device within a specific time, configuring the Wi-Fi device to a slave state and establishing a connection with the host device; and, (3) in response to receiving a mode switching command, entering an operating mode, wherein the Wi-Fi device acts as one of a perception initiating device and a perception responding device, and the second Wi-Fi device or the host device acts as the other of the perception initiating device and the perception responding device, and performs any of the methods described above.

[0068] According to another embodiment of the present invention, the Wi-Fi device further performs the following steps: (a) receiving a designated transceiver sequence, the designated transceiver sequence including parameters indicating an initiation time slot and a response time slot of the Wi-Fi device; (b) during the initiation time slot, the Wi-Fi device acts as a sensing initiator and performs any of the methods described above, and during the response time slot, the Wi-Fi device acts as a sensing responder and performs any of the methods described above. Those skilled in the art will appreciate that the designated transceiver sequence can be sent by a user to the Wi-Fi device via a terminal device.

[0069] The following, in conjunction with Figure 4 , further illustrates the workflow of a Wi-Fi device in configuration mode according to one embodiment of the present invention. In step 402, the Wi-Fi device initializes. In step 404, the Wi-Fi device enters configuration mode and scans for host devices within a predetermined range. In step 406, it determines whether a host device has been detected within a specified time period. If no host device has been detected, the Wi-Fi device is configured as a master in step 408 and a connection is established with a second Wi-Fi device in step 410. For example, the Wi-Fi device may enable its own network configuration function and wait for other devices to connect. Furthermore, when the Wi-Fi device is configured as a master, it may set its own ID to 1 and assign IDs to other devices connected to it. If a host device has been detected within a specified time period, the Wi-Fi device is configured as a slave in step 412 and a connection is established with the host device in step 414. For example, the Wi-Fi device may obtain the ID assigned to it by the scanned host device and information about the host device. After the Wi-Fi device establishes a connection with a second Wi-Fi device as a host or establishes a connection with a scanned host device as a slave, it is further determined in step 416 whether a mode switch command has been received. Once the mode switch command is received, the device enters the operating mode, and the Wi-Fi device acts as one of the sensing initiating device and the sensing responding device, and the second Wi-Fi device or the host device acts as the other of the sensing initiating device and the sensing responding device, and executes the above-described Wi-Fi-based environment sensing method.

[0070] By way of example and not limitation, a Wi-Fi device receives a designated transceiver sequence, the designated transceiver sequence including parameters indicating an initiation time slot and a response time slot of the Wi-Fi device. The Wi-Fi device entering an operational mode further includes performing the following steps: determining an initiation time slot and a response time slot of the Wi-Fi device based on the received designated transceiver sequence; during the initiation time slot, the Wi-Fi device acts as a sensing initiator and executes any of the methods described above; and during the response time slot, the Wi-Fi device acts as a sensing responder and executes any of the methods described above.

[0071] 5 , a flowchart of a working process of a Wi-Fi device in an operating mode according to an embodiment of the present invention is further described below.

[0072] In step 502 , the Wi-Fi device receives a designated transceiver sequence, where the designated transceiver sequence includes parameters indicating an initiation time slot and a response time slot of the Wi-Fi device.

[0073] In step 504 , the Wi-Fi device determines whether the current time slot is an initiation time slot or a response time slot based on the received designated transceiver sequence.

[0074] At step 506 , during the initiation time slot, the Wi-Fi device acts as a sensing initiating device and executes any of the above methods.

[0075] At step 508 , during the response time slot, the Wi-Fi device, as a sensing response device, performs any of the methods described above.

[0076] Figure 6 shows a Wi-Fi-based environment sensing system for monitoring a spatial region according to an embodiment of the present invention. The environment sensing system includes a first device 602 and a second device 604, each of which includes at least one transmitting antenna and at least one receiving antenna. The first device 602, acting as a sensing initiator, and the second device 604, acting as a sensing responder, perform any of the above methods to monitor a first spatial region between the first device 602 and the second device 604.

[0077] As an example and not a limitation, the environmental perception system also includes a third device 606, wherein the third device 606 includes at least one transmitting antenna and at least one receiving antenna; wherein the second device 604 acts as a perception initiating device and the third device 606 acts as a perception responding device to execute any of the methods described above to monitor a second spatial area between the second device 604 and the third device.

[0078] As an example but not limitation, the third device 606 as a perception initiating device and the first device 602 as a perception responding device perform any of the methods described above to monitor a third spatial area between the third device 606 and the first device 602 .

[0079] As an example and not a limitation, each of the first device, the second device, and the third device respectively receives its own designated transceiver sequence, and the designated transceiver sequence indicates an initiation time slot and a response time slot; each of the first device 602, the second device 604, and the third device 606 respectively performs any one of the methods described above as a perception initiator device during the initiation time slot indicated by the respective designated transceiver sequence, and each of the first device 602, the second device 604, and the third device 606 respectively performs any one of the methods described above as a perception responder device during the response time slot indicated by the respective designated transceiver sequence.

[0080] For example, referring to Table 1 below, an example of a designated transceiver sequence according to the present invention is shown. In this example, the first device 602 performs the method as a sensing initiator during time slots 1 and 4, and performs the method as a sensing responder during time slots 3 and 6. The second device 604 and the third device 606 similarly perform the method according to their respective designated transceiver sequences.

[0081] Table 1 An example of a designated transceiver sequence according to an embodiment of the present invention

[0082] In addition, as another example of the present invention, the first device and the second device are deployed so that the signal propagation path between the first device and the second device passes through the center of the first spatial area; the second device and the third device are deployed so that the signal propagation path between the second device and the third device passes through the center of the second spatial area; and the third device and the first device are deployed so that the signal propagation path between the third device and the first device passes through the center of the third spatial area.

[0083] It should be understood that the environment perception system according to the embodiment of the present invention may include one or more other devices in addition to the first device, the second device and the third device to monitor more spatial areas. For example, assuming that a total of n spatial areas are to be monitored, the system may include n devices A1, A2, A3...A n , where A1 and A2 devices monitor the first spatial area, A2 and A3 devices monitor the second spatial area, and so on. Each device enters the operating mode accordingly according to the initiation time slot and response time slot of its own designated transceiver timing to execute the above-mentioned environmental perception method.

[0084] Example 4

[0085] According to another embodiment of the present invention, a computer-readable storage medium is provided, on which instructions for environmental perception are stored, wherein when the instructions are executed by one or more processors, the one or more processors execute any one of the environmental perception methods described above.

[0086] Specific Example 1

[0087] The following describes an application example in conjunction with an embodiment of the present invention. In this example, a method for environmental awareness is performed using Wi-Fi devices that support the FTM protocol. Each Wi-Fi device has Wi-Fi communication capabilities and can perform FTM measurements.

[0088] In the example of the present invention, each Wi-Fi device includes the following two modes: a configuration mode and an operation mode.

[0089] Among them, the configuration mode of the Wi-Fi device is used to realize the automatic networking and network configuration of multiple Wi-Fi devices. Each Wi-Fi device is initialized first, and then scans whether there are similar Wi-Fi devices in the surrounding area in the host state. If the same type of Wi-Fi device in the host state is not scanned within the specified time, or a manually issued mode switching command is received, the Wi-Fi device will set its own ID to 1 and switch to the host state. In this way, the Wi-Fi device becomes a wireless access point, allowing other Wi-Fi devices to connect, and start the network configuration function to configure the name and password of the network access point. If the same type of Wi-Fi device in the host state is scanned within the specified time, the Wi-Fi device will automatically connect to the host device and obtain the local ID and network configuration information from the host device.

[0090] The operating mode of the Wi-Fi device is used to perceive environmental changes, obtain timing measurement results by performing FTM measurements, compare them with benchmark timing measurement results, and upload the results to the server.

[0091] Specifically, the example according to the present invention specifically includes the following steps:

[0092] 1. Deploy Wi-Fi devices: Deploy several Wi-Fi devices within the monitoring area based on its size and shape. To ensure that changes in objects or people within the monitoring area are clearly reflected in the FTM time series measurement results, the following rules should be followed during deployment: The line connecting two adjacent Wi-Fi devices should pass through the center of the monitoring area.

[0093] 2. Measure the first initial timing measurement result: In the absence of objects or people entering or leaving the monitoring area (i.e., the initial environment of the monitoring area), measure the timing measurement results between pairs of Wi-Fi devices across the monitoring area, and record them as the initial timing measurement results st0, where st0 can be the round-trip time or the arrival time. Optionally, the spatial area can be measured multiple times in different scenarios to determine at least one second initial timing measurement result as a benchmark for subsequent measurements and judgments. In some specific embodiments, at least one second initial timing measurement result may correspond to one or more measurement results of a specific change in the monitored spatial area. For example, the second initial timing measurement result may correspond to a measurement result when the length of the moving object is 0.5m, 1m, etc. For another example, the second initial timing measurement result may correspond to a measurement result when the number of people in the spatial area is one person, two people, etc.

[0094] 3. Perform monitoring: During the monitoring period, the timing measurement results between all pairs of Wi-Fi devices across the monitoring area are regularly measured and recorded as the current timing measurement result stn. The specific timing measurement process is that the Wi-Fi device acting as the sensing initiator sends a fine time measurement frame, and the Wi-Fi device acting as the sensing responder sends a fine time response frame to measure the round-trip time or arrival time of the Wi-Fi signal. The timing measurement process is as follows: the transmitter sends a measurement frame, the receiver receives the measurement frame and returns a response, and the arrival time or round-trip time of the Wi-Fi signal is measured. In addition, to avoid the problem of signal conflict caused by using multiple Wi-Fi devices for timing measurement when there are multiple monitoring areas, the following timing measurement method is adopted: for the specified monitoring areas 1, 2, 3...n, the devices at both ends of the monitoring areas 1, 2, 3...n are set as the sensing initiator device and the sensing responder device respectively to perform timing measurement, thereby obtaining the timing measurement results of all monitoring areas.

[0095] 4. Compare the difference between the timing measurement results during the monitoring period and the first initial environment timing measurement results: Determine whether an environmental change has occurred in the monitoring area based on the changes in the timing measurement results. If the absolute value of the difference between the current timing measurement result stn and the first initial timing measurement result st0 exceeds the preset time difference threshold stt, it can be considered that an object or person change has occurred in the monitoring area, such as an object or person entering or leaving. In addition, in order to further determine the size information of the object or the number of people that caused the object change, after determining that the object or person change has occurred, a fine time measurement can be performed again to obtain a second timing measurement result, and the size information of the object or the number of people that have moved in the monitoring area can be determined based on the difference between the second timing measurement result and at least one second initial timing measurement result and the preset threshold.

[0096] 5. Data Upload: The raw time measurement data and judgment results are combined and uploaded to the server. Data upload uses the chip's built-in Wi-Fi or Bluetooth Low Energy (BLE) functionality. Because FTM measurements also require the Wi-Fi device's underlying transceiver hardware, data upload and FTM measurements are performed alternately using time division multiplexing.

[0097] The present invention also provides a data upload method for unowned devices during large-scale, multi-area monitoring. Specifically, to transmit timing measurement results to the cloud or other servers, each Wi-Fi transceiver independently stores the access point name and password of the connected AP during the configuration phase. After a timing measurement is completed, the raw data and alarm data generated based on the judgment results are first synchronized to all Wi-Fi devices in the same network. During the data upload process, each Wi-Fi device first detects the Wi-Fi signal strength received from the connected wireless access point. It then selects the Wi-Fi device with the strongest signal strength to connect to the connected wireless access point and upload the data. This method enables data upload for unowned devices. Specifically, there is no need to specify a specific Wi-Fi device as the data sender. Instead, the optimal Wi-Fi device is dynamically selected for data upload based on signal strength. This avoids data upload failures or delays caused by Wi-Fi device failures or unstable signals. Furthermore, by synchronizing the raw data and alarm data to all Wi-Fi devices in the same network before uploading, data integrity and consistency are ensured, improving data security and reliability.

[0098] Specific Example 2: Environmental Perception for Vehicle Detection

[0099] (a) Single-lane vehicle detection

[0100] As shown in Figure 7, a schematic diagram of an application scenario according to a specific embodiment of the present invention is shown. For a single-lane scenario, two Wi-Fi devices, namely a first device 702 and a second device 704, are deployed on both sides of the road, one of which is set as a host device (AP) and the other is set as a slave device (STA). The timing measurement results when no car passes by are recorded as the first initial timing measurement results. Then, the two deployed Wi-Fi devices perform the steps according to the aforementioned method of the present invention to obtain the timing measurement results, and compare them with the first initial timing measurement results. When the difference between the timing measurement result and the first initial timing measurement result is greater than the threshold, it is determined that a vehicle has passed. This method utilizes the FTM timing measurement technology to achieve passive detection of vehicle changes in the environment.

[0101] (b) Multi-lane vehicle detection

[0102] FIG8 shows another application scenario schematic diagram according to a specific embodiment of the present invention. For a two-lane scenario, the road can be divided into two spatial regions of interest. To monitor vehicle conditions within these two regions, a Wi-Fi device (shown as first device 802, second device 804, and third device 806) is deployed at each edge of the road and at the central partition. The measurement sequence is as follows: 1. The first device acts as a sensing initiator and the second device acts as a sensing responder, measuring the first initial time series measurement results of the first spatial region in the diagram when no vehicle is passing; 2. The second device acts as a sensing initiator and the third device acts as a sensing responder, measuring the first initial time series measurement results of the first spatial region in the diagram when no vehicle is passing. Then, the first device and second device pair, and the second device and third device pair, respectively, periodically measure the time series measurement results and compare them with the first initial time series measurement results. When the difference between the measured time series measurement results and the first initial time series measurement results is greater than a threshold, it is determined that a vehicle has passed through the corresponding spatial region, thereby achieving perception of environmental state changes.

[0103] Specific Example 3: Environmental Perception for Security Scenarios

[0104] For security scenarios, doors, windows, corridors, etc. can be used as spatial areas of interest, and Wi-Fi devices can be deployed on both sides of them. First, under normal circumstances, that is, when no people or objects enter the spatial area of ​​interest, the timing measurement results are measured and recorded as the first initial timing measurement results. Then, the method of environmental perception according to the present invention is executed to perform timing measurement, and the timing measurement results are compared with the first initial timing measurement results. If it is found that the difference between the timing measurement result and the first initial timing measurement result exceeds the threshold, it means that an object has been moved or there are people walking in the corresponding spatial area of ​​interest, thereby triggering the monitoring alarm function.

[0105] This invention discloses a method for sensing environmental changes using Wi-Fi FTM functionality. This method uses multiple Wi-Fi devices with FTM functionality as hardware devices to detect and report changes in objects and people in the monitored area. This method has the following advantages:

[0106] 1. It only needs to use existing Wi-Fi equipment, which reduces costs and maintenance difficulties, and is easy to deploy without additional wiring.

[0107] 2. The technical solution of this invention utilizes the FTM protocol, which is unaffected by ambient light and dust. The key to FTM technology is the accurate measurement of the time difference between transmitted and received frames, which is converted into distance or position information. FTM is independent of signal strength, thus providing precise positioning and distance measurement even in complex wireless channel environments. Compared to traditional CSI-based environmental sensing, this avoids issues such as unstable sensing results caused by environmental interference.

[0108] 3. The present invention also designs a method for arranging the transmission and reception scheduling of Wi-Fi devices by specifying the transmission and reception timing, thereby realizing environmental perception of multiple spatial areas.

[0109] 4. The data upload method without master device is adopted to improve the efficiency and reliability of data transmission.

[0110] 5. The present invention also adopts a method of filtering after multiple measurements to improve measurement accuracy and robustness.

[0111] Although various embodiments of various aspects of the present invention have been described for the purposes of this disclosure, it should not be understood that the teachings of this disclosure are limited to these embodiments. Features disclosed in a specific embodiment are not limited to that embodiment, but can be combined with features disclosed in different embodiments. For example, one or more features and / or operations of the method according to the present invention described in one embodiment may also be applied individually, in combination or as a whole in another embodiment. In addition, it should be understood that the method steps described above can be performed sequentially, in parallel, combined into fewer steps, split into more steps, combined and / or omitted in a manner different from that described. It should be understood by those skilled in the art that there are possible more optional embodiments and variations, and various changes and modifications can be made to the above-mentioned method steps without departing from the scope defined by the claims of the present invention.

Claims

1. A Wi-Fi-based environment perception method for monitoring a spatial area, characterized in that: The method comprises: sending at least one first fine time measurement frame from the sensing initiating device to the sensing responding device; The sensing initiating device receives at least one first fine time response frame sent by the sensing responding device; determining a first timing measurement result between the perception initiating device and the perception responding device according to the at least one first fine time measurement frame and the at least one first fine time response frame; and The state change information in the spatial area is determined according to whether the difference between the first timing measurement result and the first initial timing measurement result exceeds a threshold.

2. The method according to claim 1, characterized in that The state change information of the spatial area indicates whether an object or a person moves in the spatial area.

3. The method according to claim 2, characterized in that In response to the state change information indicating that an object or a person moves in the spatial area, the method further includes: sending at least one second fine time measurement frame from the awareness initiating device to the awareness responding device; The sensing initiating device receives at least one second fine time response frame sent by the sensing responding device; determining a second timing measurement result between the perception initiating device and the perception responding device according to the at least one second fine time measurement frame and the at least one second fine time response frame; and The size information of the object or person moving in the spatial area is determined according to the second time series measurement result and the at least one second initial time series measurement result.

4. The method according to claim 1, characterized in that: The determining a first timing measurement result between the perception initiating device and the perception responding device includes: A plurality of timing measurement results obtained based on a plurality of the first fine time measurement frames and a plurality of the first fine time response frames are filtered to obtain filtered values ​​of the plurality of timing measurement results, and the filtered values ​​are used as the first fine timing measurement results.

5. The method according to claim 3, characterized in that: The determining a second timing measurement result between the perception initiating device and the perception responding device includes: A plurality of timing measurement results obtained based on a plurality of the second fine time measurement frames and a plurality of the second fine time response frames are filtered to obtain filtered values ​​of the plurality of timing measurement results, and the filtered values ​​are used as the second fine timing measurement results.

6. The method according to claim 1, characterized in that In response to determining that the difference between the first timing measurement result and the first initial timing measurement result exceeds the threshold for a consecutive predetermined number of times and / or within a consecutive predetermined time, the first initial timing measurement result is remeasured and updated.

7. The method according to claim 3, characterized in that Also includes: In response to determining the first timing measurement result and / or the second timing measurement result, the first timing measurement result and / or the second timing measurement result are synchronized to one or more Wi-Fi devices in the same network as the awareness initiating device and / or the awareness responding device.

8. The method according to claim 1, characterized in that The perception initiating device and the perception responding device are arranged such that a signal propagation path between the perception initiating device and the perception responding device passes through the spatial region.

9. A Wi-Fi device for environmental awareness, used for monitoring a spatial area, characterized in that: The Wi-Fi device includes: a processor; a memory; and a transceiver operating in conjunction with the processor; The memory stores computer instructions, and when the computer instructions are executed by the at least one processor, the Wi-Fi device performs the following steps: Enter the configuration mode and scan the host devices within the predetermined range; In response to not scanning the host device within a specific time, configuring the Wi-Fi device to be in a host state and establishing a connection with a second Wi-Fi device; or, in response to scanning the host device within a specific time, configuring the Wi-Fi device to be in a slave state and establishing a connection with the scanned host device; and In response to receiving a mode switching command, entering an operating mode, the Wi-Fi device serves as one of a perception initiating device and a perception responding device, and the second Wi-Fi device or the host device serves as the other of the perception initiating device and the perception responding device, and executes the method according to any one of claims 1 to 8.

10. The Wi-Fi device according to claim 9, characterized in that: The Wi-Fi device receives a specified transceiver sequence, wherein the specified transceiver sequence includes parameters indicating an initiation time slot and a response time slot of the Wi-Fi device; The Wi-Fi device entering the operating mode further includes: Determining, according to the designated transceiver sequence, an initiation time slot and a response time slot of the Wi-Fi device; During the initiation time slot, the Wi-Fi device as the awareness initiating device performs the method according to any one of claims 1-8, and During the response time slot, the Wi-Fi device, as the sensing response device, executes the method according to any one of claims 1 to 8.

11. A Wi-Fi-based environmental perception system for monitoring a spatial area, characterized in that: The environment sensing system comprises a first device and a second device, wherein the first device and the second device respectively comprise at least one transmitting antenna and at least one receiving antenna; The first device as a perception initiating device and the second device as a perception responding device execute the method according to any one of claims 1-8 to monitor a first spatial area between the first device and the second device.

12. The system according to claim 11, characterized in that The environment sensing system further includes a third device, wherein the third device includes at least one transmitting antenna and at least one receiving antenna; The second device as a perception initiating device and the third device as a perception responding device execute the method according to any one of claims 1-8 to monitor a second spatial area between the second device and the third device.

13. The system according to claim 12, characterized in that in, The third device as a perception initiating device and the first device as a perception responding device execute the method according to any one of claims 1-8 to monitor a third spatial area between the third device and the first device.

14. The system according to claim 12, characterized in that Each of the first device, the second device, and the third device receives a respective designated transceiver sequence, the designated transceiver sequence indicating an initiation time slot and a response time slot; Each of the first device, the second device and the third device respectively performs the method according to any one of claims 1 to 8 as the sensing initiating device during the initiating time slot indicated by the respective designated transceiver sequence, and Each of the first device, the second device and the third device respectively performs the method according to any one of claims 1 to 8 as the sensing response device during a response time slot indicated by the respective designated transceiver sequence.

15. The system according to claim 12, characterized in that The first device and the second device are arranged such that a signal propagation path between the first device and the second device passes through the first spatial region; The second device and the third device are arranged such that a signal propagation path between the second device and the third device passes through the second spatial region; as well as The third device and the first device are disposed such that a signal propagation path between the third device and the first device passes through the third spatial region.

16. A computer-readable storage medium having instructions stored thereon, characterized in that: in, When the instructions are executed by one or more processors, the one or more processors are caused to perform the method according to any one of claims 1 to 8.

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