Free connection CSI high frequency acquisition method, alarm system and activation switch

Abstract

The application discloses a connection-free CSI high-frequency acquisition method, an alarm system and an activation switch, relates to the technical field of wireless communication, and solves the technical problem that the prior art is difficult to acquire CSI in a high frequency through a connection-free mode. The acquisition method comprises the following steps: acquiring original beacon data packets broadcast by all AP devices in an environment under each preset frequency band; extracting all original beacon data packet information; screening all original beacon data packets, and establishing a beacon data packet scanning plan; and acquiring CSI of a wireless local area network receiver from target beacon data packets according to the beacon data packet scanning plan. According to the application, the CSI can be acquired without establishing a WiFi connection with the AP device, meanwhile, the CSI of all AP devices in a communication signal receiving range can be acquired, the number of CSI sources and the CSI coverage area are increased, and the high-frequency acquisition of the CSI is realized.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a connectionless CSI high-frequency acquisition method, an alarm system, and an activation switch. Background Technology

[0002] Channel State Information (CSI) is the channel state information between two wireless devices. Defined starting with version 802.11n, it reports channel state information between WiFi router devices (Access Points, APs) and client user station devices (Stations, STAs), used for transmission beamforming and multi-user MIMO in OFDM modems. Currently, some chips from Intel and Qualcomm allow users to obtain CSI from OFDM (802.11g / n) data packets. In recent years, CSI has seen numerous new applications in areas such as positioning, motion detection, gesture recognition, target velocity estimation, fall detection, indoor human density estimation, and respiratory rate estimation.

[0003] For example, in positioning applications, there is theoretically a one-to-one mapping between the receiver's location and the CSI (Received Signal Strength Indication) of multiple surrounding transmitters. Therefore, by collecting the CSI of the terminal's location, the terminal's position can be determined, thus achieving the effect of positioning the terminal. In gesture recognition applications, the recognition task can be accomplished by distinguishing the differences in displacement caused by different gestures during signal propagation. The attenuation of WiFi signals during propagation is generally recorded using Received Signal Strength Indication (RSSI) and CSI. Since the introduction of CSI into WiFi technology, WiFi-based gesture recognition has gradually shifted its focus to CSI.

[0004] Based on currently available chip technology, CSI can be obtained in three ways at a predictable high frequency. (1) STA devices in a wireless LAN frequently and periodically send probe request packets to AP devices. CSI can be obtained from the probe response packets sent back by the AP devices, but this introduces additional traffic, thereby reducing the overall network throughput. (2) STA devices connect to AP devices and initiate periodic upload or download packet streams. STA devices can obtain CSI from the packets of AP devices. If the AP device is in protected mode, not only will additional traffic be introduced, but a password is also required to establish a connection. In addition, it can only obtain CSI from a single AP device at any given time. (3) CSI can be obtained in a connectionless manner from the 5GHz or 2.4GHz band via periodic beacon packets from the AP devices. This method does not introduce additional traffic overhead, but the frequency of obtaining new CSI is limited by the Target Beacon Transmission Time (TBTT) or the AP device, typically 102.4 milliseconds per beacon packet transmission period. In DSSS (Direct Sequence Spread Spectrum) / CCK (Complementary Code Keying) mode, CSI cannot be obtained directly. CSI can be obtained by converting the time domain CIR (Channel Impulse Response) (for details of the method, please refer to the patent "Method, Apparatus and Computer Equipment for Obtaining Channel State Information CSI", publication number CN111726199A).

[0005] In the process of realizing this invention, the inventors discovered at least the following problems in the prior art:

[0006] Existing methods for acquiring channel state information (CSO) are unable to acquire CSO information in wireless local area networks (WLANs) at high frequencies without requiring connections, thus affecting CSO-based applications. Summary of the Invention

[0007] The purpose of this invention is to provide a connectionless CSI high-frequency acquisition method, an alarm system, and an activation switch to solve the problem that existing channel state information acquisition methods are unable to acquire channel state information in wireless local area networks at high frequencies in a connectionless manner, thus affecting the technical problems of channel state information-based applications. The various technical effects of the preferred solutions among the many technical solutions provided by this invention are detailed below.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] This invention provides a connectionless CSI high-frequency acquisition method, comprising the following steps:

[0010] S100: Under each preset frequency band, the wireless LAN receiver performs channel selection under the preset frequency band, performs single or multiple scans on the selected channels, and acquires the raw beacon data packets broadcast by all AP devices in the environment; S200: Extract the beacon feature information of all the raw beacon data packets, acquire the information of the preset frequency band and its channel number information, BSSID and / or the MAC address of the AP device, TBTT, single or multiple RSSI and / or SNR scan information, and CSI / CIR scan information obtained from single or multiple scans; S300: Filter all the raw beacon data packets according to the beacon feature information and CSI acquisition frequency requirements to obtain a first result beacon data packet and the corresponding first target AP device set, and establish a first beacon data packet scanning plan; S400: According to the first beacon data packet scanning plan, receive the first target beacon data packets from the first target AP device set in multiple channels of the preset frequency band, and acquire the CSI of the wireless LAN receiver from the first target beacon data packets.

[0011] Preferably, steps S300 to S400 are replaced by S300' to S500':

[0012] S300': Based on the beacon feature information and CSI acquisition frequency requirements, all the original beacon data packets are filtered to obtain second result beacon data packets and corresponding second target AP device sets. Based on the CSI acquisition frequency requirements, it is determined whether the second result beacon data packets meet the requirements. If yes, proceed to S400'; otherwise, proceed to S500'. S400': Based on the CSI acquisition frequency requirements, a second beacon data packet scanning plan is established. Second target beacon data packets from multiple second target AP device sets are received in multiple channels of the preset frequency band, and the wireless LAN reception information is obtained from the second target beacon data packets. S500': Establish a third beacon data packet scanning plan according to the CSI acquisition frequency requirements, and receive second target beacon data packets from multiple sets of second target AP devices in multiple channels; at the same time, the wireless LAN receiver actively sends probe request packets, short data packets or RTS data frames to the second target AP device sets to obtain probe response packets, acknowledgment data packets or CTS data frames sent back by the second target AP device sets, respectively, and obtain the CSI of the wireless LAN receiver through the second target beacon data packets and at least one of the probe response packets, acknowledgment data packets, and CTS frames.

[0013] Preferably, in step S100, the preset frequency band includes one or more of 2.4GHz, 5GHz, and 6GHz; in the 5GHz and 6GHz frequency bands, CSI is obtained through OFDM protocol data unit or OFDMA protocol data unit; in the 2.4GHz frequency band, CIR is obtained through DSSS protocol data unit and transformed to obtain CSI.

[0014] Preferably, in step S200, the TBTT, BSSID, and MAC address of the AP device are directly decoded from the original beacon data packet, and the timestamp of the AP device and the TSF timestamp of the wireless LAN receiver are also decoded at the same time.

[0015] Preferably, the first beacon data packet scanning plan, the second beacon data packet scanning plan, and the third beacon data packet scanning plan all include CSI acquisition frequency requirements, TBTT, BSSID and / or the MAC address of the AP device, frequency band and channel information, and at least one of the following parameters: RSSI and / or SNR scanning information, CSI / CIR scanning information.

[0016] Preferably, in step S200, the CSI / CIR scanning information is CSI and / or CIR, and the initial CSI / CIR scanning information includes one or more of the following CSI / CIR parameters: spectral flatness information, average channel strength information, amplitude and phase information of each subcarrier channel, average channel delay spread information, and root mean square information of channel delay spread.

[0017] Preferably, the initial CSI / CIR scan information is measured by a single iterative scan or multiple iterative scans, and the subsequent CSI / CIR scan information also includes the time-series change information of the CSI / CIR parameters to obtain statistical information of various types of information in the CSI / CIR parameters. This statistical information includes the minimum value, maximum value, average value, standard deviation, and parameter change rate.

[0018] Preferably, in step S300, the beacon data packet scanning plan further includes establishing a whitelist and / or blacklist for the AP device. The whitelist and blacklist are determined by any combination of the AP device's MAC address, and / or BSSID, and / or time-series change information and / or statistical information of different information in the CSI / CIR parameters.

[0019] Preferably, the beacon data packet scanning plan also includes a timetable. In step S400, the wireless LAN receiver adjusts to the corresponding frequency band and channel according to the timetable and verifies the received beacon data packets through the BSSID or the MAC address of the target AP device set.

[0020] Preferably, in S500', the wireless LAN receiver adjusts to the selected channel and preset frequency band according to the CSI acquisition frequency requirement in S300'. In addition to passively scanning beacon packets, the wireless LAN receiver simultaneously sends request packets to the target AP device and captures response packets from the target AP device to meet the CSI acquisition frequency requirement. In S400' or S500', at least CSI / CIR scan information and RSSI are measured and / or calculated from the beacon packets or request packets, then recorded, and the first beacon packet scanning plan, the second beacon packet scanning plan, and the third beacon packet scanning plan are dynamically updated using the information obtained in S200.

[0021] An alarm system that operates using any of the connectionless CSI high-frequency acquisition methods described above.

[0022] An activation switch is provided, which is activated by any of the above-described connectionless CSI high-frequency acquisition methods, so that the light can be turned on automatically when the user enters the switch area.

[0023] Implementing one of the above-described technical solutions of the present invention has the following advantages or beneficial effects:

[0024] The wireless LAN receiver of this invention can acquire surrounding CSI without establishing a WiFi connection with the access point (AP) device, without interrupting ordinary wireless LAN communication or introducing additional communication overhead. Therefore, it does not affect the normal transmission and reception of wireless LAN signals and does not reduce network speed. Simultaneously, the wireless LAN receiver can acquire the CSI of all AP devices within the communication signal reception range, increasing the number of CSI sources and the CSI coverage area. It also supports scanning of different frequency bands, realizing high-frequency cross-band CSI acquisition, and providing better support for CSI applications in new fields. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0026] Figure 1 This is a flowchart of Embodiment 1 of the present invention;

[0027] Figure 2 This is a flowchart of Embodiment 2 of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, various exemplary embodiments described below will be referenced to the accompanying drawings, which form part of the exemplary embodiments, illustrating various exemplary embodiments that may be used to implement the present invention. Unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. It should be understood that they are merely examples of processes, methods, and apparatuses consistent with some aspects of the present invention disclosed as detailed in the appended claims, and other embodiments may be used, or structural and functional modifications may be made to the embodiments listed herein without departing from the scope and spirit of the present invention.

[0029] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," etc., indicate the orientation or positional relationship based on the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the referred element must have a specific orientation, or be constructed and operated in a specific orientation. The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. The term "multiple" means two or more. The terms "connected" and "linked" should be interpreted broadly, for example, they can be fixed connections, detachable connections, integral connections, mechanical connections, electrical connections, communication connections, direct connections, indirect connections through an intermediate medium, and can be the internal connection of two elements or the interaction relationship between two elements. The term "and / or" includes any and all combinations of one or more of the related listed items. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0030] To illustrate the technical solution described in this invention, specific embodiments are described below, showing only the parts related to the embodiments of this invention.

[0031] Example 1:

[0032] like Figure 1As shown, this invention provides a connectionless CSI high-frequency acquisition method, comprising the following steps: S100: Under each preset frequency band, a wireless LAN receiver performs channel selection within the preset frequency band, and performs one or more scans on the selected channel to acquire the raw beacon data packets broadcast by all AP devices in the environment. The preset frequency bands include all frequency bands supported by the wireless LAN, thereby enabling this invention to acquire channel status information from multiple frequency bands. The wireless LAN receiver acquires the raw beacon data packets broadcast by all AP devices in the environment through passive scanning, without needing to establish a WiFi connection with the AP devices, achieving connectionless acquisition, and can perform one or more scans as needed. S200: Extract the beacon feature information of all raw beacon data packets, acquire the information of the preset frequency band and its channel number information, and BSSID and / or the MAC address of the AP device, and TBTT, and one or more RSSI and / or SNR scan information, and CSI / CIR scan information obtained from one or more scans. All five types of beacon feature information mentioned above need to be acquired, but some beacon feature information can acquire one or two indicators, such as BSSID and / or AP device MAC address, RSSI and / or SNR scan information, and CSI / CIR scan information. Among them, preset frequency band information and channel number information are used to confirm physical connection information; BSSID (Basic Service Set Identifier, which enables WLAN receivers to distinguish different AP devices) and MAC (Media Access Control Address) address are used to distinguish different AP devices in the environment; RSSI and / or SNR (SNR is signal-to-noise ratio, and both RSSI and RSI can be used to determine whether the received beacon data packets are within the threshold range, that is, whether the received signal strength or signal-to-noise ratio meets the minimum requirements for CSI application); TBTT (used to determine the arrival time of beacon data packets from different AP devices, thereby establishing high-frequency CSI queue information); and CSI / CIR scan information is used to calculate CSI or CIR. S300: Based on beacon characteristic information and CSI acquisition frequency requirements, all raw beacon data packets are filtered, such as excluding certain AP devices, AP devices with poor signal strength, and AP devices with TBTT overlap, to obtain the first result beacon data packets that meet the requirements and the corresponding first target AP device set (generally including multiple different AP devices, each result data packet in the first result beacon data packet generally corresponds one-to-one with the AP devices in the first target AP device set), and a first beacon data packet scanning plan is established. CSI that meets the acquisition frequency requirements can be obtained through the first beacon data packet scanning plan.S400: According to the first beacon data packet scanning plan, the first target beacon data packet from the first target AP device set is received in multiple channels within a preset frequency band, and the CSI of the wireless LAN receiver is obtained from the first target beacon data packet. Each frequency band of the wireless LAN includes multiple channels, such as 13 channels in the 2.4GHz band. Receiving on multiple channels ensures complete acquisition of the beacon data packets from the AP devices. The wireless LAN receiver of this invention does not require establishing a WiFi connection with the AP devices, does not interrupt ordinary wireless LAN communication, and does not introduce additional communication overhead, thus not affecting the normal transmission and reception of wireless LAN signals and not reducing network speed. Simultaneously, the wireless LAN receiver can acquire the CSI of all AP devices within the communication signal reception range, increasing the number of CSI sources and the CSI coverage area. It supports scanning of different frequency bands, realizing high-frequency cross-band acquisition of CSI, and providing better support for the application of CSI in new fields. In modern urban environments, people can easily see 10 to 50 AP devices in the surrounding area from multiple directions. After filtering the original beacon data packets, it is easy to obtain CSI stably and with high quality. This invention can achieve high-frequency and predictable acquisition of CSI, and the interval is much smaller than that of typical TBTT of AP devices, which creates conditions for the application of CSI in more complex scenarios.

[0033] As an optional implementation, in step S100, the preset frequency band includes one or more of 2.4GHz, 5GHz, and 6GHz, thereby realizing the CSI acquisition of the present invention across multiple frequency bands. The CSI for the 2.4GHz and 5GHz bands can be obtained from AP devices supporting 802.11a / b / g / n / ac / ax, while the CSI for the 6GHz band can only be obtained from AP devices supporting 802.11ax (a new band added in WiFi 6E). In the 5GHz or 6GHz band, channel state information is obtained through OFDM Protocol Data Unit (OFDM PPDU) or OFDMA Protocol Data Unit (OFDMA PPDU). Since the 5GHz or 6GHz band supports OFDM or OFDMA protocols, the CSI of the AP device can be obtained using existing technologies. The channel impulse response (CIR) is obtained from the DSSS protocol data unit (DSSS PPDU) in the 2.4 GHz band, and the channel state information is obtained through FFT (Fourier transform). Specifically, the method in the applicant's published patent "Method, Apparatus and Computer Equipment for Obtaining Channel State Information" (publication number CN111726199A) can be adopted.

[0034] As an optional implementation, in step S200, the TBTT, BSSID, and MAC address of the AP device are directly decoded from the original beacon data packet. Simultaneously, the timestamp of the AP device and the TSF timestamp of the wireless LAN receiver are also decoded; the timestamps are used for time synchronization. This information can be collectively referred to as decoded information, which is information obtained from the original beacon data packet. RSSI and / or SNR scan information and CSI / CIR scan information are obtained by scanning the AP device multiple times, wherein RSSI and / or SNR are received from the physical layer of the AP device and are used to evaluate signal quality.

[0035] As an optional implementation, in step S300, the required parameters in the first, second, and third beacon data packet scanning plans all include: CSI acquisition frequency requirement, TBTT, BSSID and / or AP device MAC address, frequency band and channel information, and at least one of the following parameters: RSSI and / or SNR scanning information, and CSI / CIR scanning information. The CSI acquisition frequency requirement is the minimum CSI frequency required for CSI application, used to determine whether passive acquisition via CSI in the current receiving environment meets application requirements. TBTT is used to determine the arrival order of beacon data packets broadcast by each AP device. BSSID and AP device MAC address are used to distinguish different AP devices. Frequency band and channel information are used to achieve accurate reception of beacon data packets, including all frequency bands and channel information, so that the wireless LAN receiver can comprehensively receive beacon data packets sent by AP devices. RSSI and SNR are used to determine the signal strength of the AP device corresponding to the beacon data packet. The multiple parameters in the beacon data packet scanning plan make the beacon data packet scanning more comprehensive.

[0036] As an optional implementation, in step S200, the CSI / CIR scan information is CSI and / or CIR. The initial CSI / CIR scan information includes one or more of the following CSI / CIR parameters: spectral flatness information, average channel strength information, amplitude and phase information of each subcarrier channel, average channel delay spread information, and root mean square information of channel delay spread. The initial CSI / CIR scan information is measured through a single iteration scan or multiple iteration scans. Subsequent CSI / CIR scan information also includes the time-series variation information of the CSI / CIR parameters, as well as the statistical information of various types of information in the CSI / CIR parameters obtained through the time-series variation information, namely, the statistical information of spectral flatness information, average channel strength information, amplitude and phase information of each subcarrier channel, and channel delay spread information. This statistical information includes minimum value, maximum value, average value, standard deviation, and parameter change rate. Of course, other types of statistical information, such as variance and median, can also be added according to actual needs, which will not be elaborated here. The time-series variation information and statistical information of CSI / CIR parameters enrich the content of CSI, making it easier to implement CSI applications in more complex scenarios and further expand the corresponding functions.

[0037] As an optional implementation, in step S300, the beacon data packet scanning plan also includes a whitelist and / or a blacklist. The whitelist and blacklist are determined by any combination of the MAC address of the AP device, and / or BSSID, and / or time-series change information and / or statistical information of various information in the CSI / CIR parameters. MAC address and BSSID can be used to uniquely distinguish different AP devices, but their configuration is relatively cumbersome and time-consuming. Any combination of time-series change information and / or statistical information of various information in the CSI / CIR parameters facilitates the implementation of a more flexible whitelist and blacklist mechanism. This allows for the selection of different types of whitelist and blacklist mechanisms based on different types of CSI applications. Whitelists and blacklists facilitate targeted management of AP devices in the surrounding environment, enabling personalized settings of the receiving environment to obtain more ideal CSI. For example, a beacon scanning plan can select all AP devices in all non-overlapping channels of the 2.4GHz, 5GHz, and 6GHz bands, provided that the RSSI in the 5GHz band is greater than -46dBm or the RSSI in the 2.4GHz band is greater than -40dBm. This can be used to detect human respiratory rate or body movement targets within a radius of approximately 10 meters. For example, a beacon scanning plan can select all AP devices in all 2.4GHz, 5GHz, and 6GHz channels where the RSSI is within a given range and the SNR is higher than a given threshold. The selection of the scanning scheme is based on the requirements of each different application. If the scanning plan set using the whitelist filtering standard can meet the maximum beacon scanning interval requirement of the application, then it will passively perform the actual scan in step S400; otherwise, it will send additional request packets to trigger an AP device response when the scheme in Embodiment 2 needs to be executed.

[0038] As an optional implementation, the first beacon data packet scanning plan, the second beacon data packet scanning plan, and the third beacon data packet scanning plan also include a timetable. The wireless LAN receiver adjusts to the corresponding frequency band and channel according to the timetable and verifies the received beacon data packets through the BSSID or the MAC address of the AP device, thereby realizing automatic acquisition of CSI and facilitating the operation of CSI-based applications.

[0039] As an optional implementation, the wireless LAN receiver is a STA device and the AP device is a wireless router. Both devices are readily available, facilitating the implementation of this invention and reducing usage costs.

[0040] The embodiment is merely a specific example and does not indicate that this is the only way to implement the present invention.

[0041] Example 2:

[0042] This second embodiment is a hybrid active-passive CSI acquisition scheme, which differs from the first embodiment in that:

[0043] Steps S300 to S400 in Example 1 are replaced with S300' to S500'. S300': All original beacon data packets are filtered according to beacon feature information and CSI acquisition frequency requirements to obtain second result beacon data packets and corresponding second target AP device sets. Based on the CSI acquisition frequency requirements, it is determined whether the second result target beacon data packets meet the requirements. If yes, proceed to S400'; otherwise, proceed to S500'. If any two TBTTs exceed the maximum time interval for CSI acquisition, it is determined that the second target beacon data packets do not meet the requirements, meaning that all CSIs scanned and acquired by the WLAN receiver do not meet the requirements of the CSI application; otherwise, the requirements are met. S400': A second beacon data packet scanning plan is established according to the CSI acquisition frequency requirements. Second target beacon data packets from multiple second target AP device sets are received in multiple channels within a preset frequency band, and the CSI of the WLAN receiver is obtained from the second target beacon data packets. When all CSIs scanned and acquired by the WLAN receiver meet the requirements of the CSI application, the method in Example 1 can continue to be used to obtain the CSI. S500': Based on the CSI acquisition frequency requirements, a third beacon data packet scanning plan is established. Target beacon data packets from multiple sets of second target AP devices are received on multiple channels. Simultaneously, the WLAN receiver actively sends probe request packets, short data packets, or RTS data frames to the second target AP device sets to obtain probe response packets, acknowledgment packets, or CTS data frames sent back by the second target AP device sets (of course, this is done individually by each AP device in the second target AP set). The WLAN receiver's CSI is obtained through the second target beacon data packets, and at least one of the probe response packets, acknowledgment packets, or CTS data frames. The WLAN receiver can send active probe request packets, short data packets, or RTS frames within the desired time and channel / frequency band to invite probe response packets, acknowledgment packets, or CTS data frames from the AP routers. The specific sending time, channel, and frequency band can be comprehensively determined based on the number of APs, corresponding TBTT, AP locations, etc., in the actual environment, thereby effectively ensuring the CSI acquisition frequency. In this embodiment, CSI can be extracted from probe response packets, acknowledgment packets, CTS data frames, or beacon packets. When there are few AP devices in the surrounding environment, making it difficult to meet the CSI application requirements, actively sending probe request packets, short data packets, or RTS data frames improves the applicability of the present invention and can effectively meet more CSI application requirements.

[0044] As an optional implementation, in S500', the wireless LAN receiver adjusts to the selected channel and preset frequency band according to the CSI acquisition frequency requirement in S300'. In addition to passively scanning beacon packets, the wireless LAN receiver simultaneously sends request packets to the target AP device and captures response packets from the target AP device to meet the CSI acquisition frequency requirement. When the CSI obtained by passive scanning cannot meet the application requirements, the CSI acquisition frequency requirement is met by combining active scanning with passive scanning. In S400' or S500', at least CSI / CIR scan information and RSSI are measured and / or calculated from beacon packets or request packets, then recorded, and the first beacon packet scanning plan, the second beacon packet scanning plan, and the third beacon packet scanning plan are dynamically updated using the information obtained in S200 (the specific information can be selected as needed). Through dynamic updating, a more comprehensive and accurate acquisition of CSI can be achieved.

[0045] Example 3:

[0046] An alarm system operates using the connectionless CSI high-frequency acquisition method described in Embodiment 1 or 2. A whitelist can be set in the beacon scanning plan, selecting all AP devices in all WiFi channels within the 2.4 GHz band when the RSSI is below a threshold. For example, a reliable and stable beacon signal from a nearby AP device is indicated when the RSSI threshold is -70 dBm, and the temporal variation of its CSI strength is below the threshold and its CSI spectral flatness is above a given value. This scanning plan can then be used in a WiFi-based security alarm system to detect unauthorized opening of doors and windows in offices or residential units. In step S200, the identification of a specific window or door in the protected area can be associated, linking a specific CSI / CIR / RSSI profile to the opening and closing of that specific door / window in the application. This enables low-cost installation of the alarm system without the need for separate sensors, thus reducing costs.

[0047] Example 4:

[0048] A switch activation method is disclosed, which activates the switch using the connectionless CSI high-frequency acquisition method described in Embodiment 1 or 2, enabling the lights to automatically turn on when a user enters the switch area. A whitelist is set in the beacon scanning plan, selecting all AP devices in all WiFi channels across the 2.4G / 5G / 6GHz bands, under the conditions that the RSSI is higher than a selected threshold and the time variation of its CSI strength is lower than the threshold, and that the CSI spectral characteristics meet a given profile. This implements a WiFi-based motion-activated light switch, allowing the lights to automatically turn on when someone enters the room.

[0049] Example 5:

[0050] A CSI procedure, based on the connectionless CSI high-frequency acquisition method in Embodiment 1 or 2, is available for line-of-sight (LOS) wireless transmission. A whitelist is set in the beacon scanning plan, selecting all AP devices in all WiFi channels across the 2.4G / 5G / 6GHz bands. This procedure can be used for CSI applications requiring LOS wireless transmission when the CSI root mean square (RMS) delay spread is below a threshold and the SNR is above a threshold.

[0051] The above description is merely a preferred embodiment of the present invention. Those skilled in the art will understand that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the present invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A connectionless CSI high-frequency acquisition method, characterized in that, Includes the following steps: S100: Under each preset frequency band, the wireless LAN receiver performs channel selection under the preset frequency band, performs one or more scans on the selected channel, and obtains the original beacon data packets broadcast by all AP devices in the environment. S200: Extract all the beacon feature information of the original beacon data packets, obtain the information of the preset frequency band and its channel number information, BSSID and / or the MAC address of the AP device, TBTT, single or multiple RSSI and / or SNR scan information, and CSI / CIR scan information obtained from single or multiple scans; S300': Based on the beacon feature information and CSI acquisition frequency requirements, all the original beacon data packets are filtered to obtain the second result beacon data packets and the corresponding second target AP device set. Based on the CSI acquisition frequency requirements, it is determined whether the second result beacon data packets meet the requirements. If yes, proceed to S400'; otherwise, proceed to S500'. S400': Establish a second beacon data packet scanning plan according to the CSI acquisition frequency requirements, receive second target beacon data packets from multiple sets of second target AP devices in multiple channels of the preset frequency band, and obtain the CSI of the wireless LAN receiver from the second target beacon data packets; S500': Establish a third beacon data packet scanning plan according to the CSI acquisition frequency requirements, and receive second target beacon data packets from multiple sets of second target AP devices in multiple channels; at the same time, the wireless LAN receiver actively sends probe request packets, short data packets or RTS data frames to the second target AP device sets to obtain probe response packets, acknowledgment data packets or CTS data frames sent back by the second target AP device sets respectively, and obtain the CSI of the wireless LAN receiver through the second target beacon data packets and at least one of the probe response packets, acknowledgment data packets, and CTS frames.

2. The connectionless CSI high-frequency acquisition method according to claim 1, characterized in that, In step S100, the preset frequency band includes one or more of 2.4GHz, 5GHz, and 6GHz; in the 5GHz and 6GHz frequency bands, CSI is obtained through OFDM protocol data unit or OFDMA protocol data unit; in the 2.4GHz frequency band, CIR is obtained through DSSS protocol data unit and transformed to obtain CSI.

3. The connectionless CSI high-frequency acquisition method according to claim 1, characterized in that, In step S200, the TBTT, BSSID, and MAC address of the AP device are directly decoded from the original beacon data packet. The timestamp of the AP device and the TSF timestamp of the wireless LAN receiver are also decoded at the same time.

4. The connectionless CSI high-frequency acquisition method according to claim 1, characterized in that, Both the second and third beacon data packet scanning plans include CSI acquisition frequency requirements, TBTT, BSSID and / or the MAC address of the AP device, frequency band and channel information, and at least one of the following parameters: RSSI and / or SNR scanning information, CSI / CIR scanning information.

5. The connectionless CSI high-frequency acquisition method according to claim 4, characterized in that, In step S200, the CSI / CIR scanning information is CSI and / or CIR, and the initial CSI / CIR scanning information includes one or more of the following CSI / CIR parameters: spectral flatness information, average channel strength information, amplitude and phase information of each subcarrier channel, average channel delay spread information, and root mean square information of channel delay spread.

6. The connectionless CSI high-frequency acquisition method according to claim 5, characterized in that, The initial CSI / CIR scan information is measured through a single iterative scan or multiple iterative scans. Subsequent CSI / CIR scan information also includes time-series change information of the CSI / CIR parameters to obtain statistical information of various types of information in the CSI / CIR parameters. This statistical information includes minimum value, maximum value, average value, standard deviation, and parameter change rate.

7. The connectionless CSI high-frequency acquisition method according to claim 1, characterized in that, In S500', the wireless LAN receiver will adjust to the selected channel and preset frequency band according to the CSI acquisition frequency requirement in S300'. In addition to passively scanning beacon packets, the wireless LAN receiver will simultaneously send request packets to the target AP device and capture response packets from the target AP device to meet the CSI acquisition frequency requirement. In S400' or S500', at least CSI / CIR scan information and RSSI are measured and / or calculated from the beacon packets or request packets, then recorded, and the second beacon packet scan plan and the third beacon packet scan plan are dynamically updated using the information obtained in S200.

8. An alarm system, characterized in that, The alarm system operates using the connectionless CSI high-frequency acquisition method described in any one of claims 1-7.

9. An activation switch, characterized in that, The switch is activated by the connectionless CSI high-frequency acquisition method described in any one of claims 1-7, so that the lights can be turned on automatically when the user enters the switch area.

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