Improved Wi-Fi sensing procedure

Abstract

This specification proposes a new signal transmission / reception procedure between STAs when sensing measurement initiated by a STA other than the AP is performed. According to one embodiment of this specification, a sensing measurement procedure is proposed in which a STA other than the AP transmits a sensing start frame to the AP, whereby the AP requests a responder STA to transmit an NDP frame. According to another embodiment of this specification, a method for configuring frames transmitted and received in the procedure is proposed.

Description

[Technical field]

[0001] This specification relates to wireless LAN systems, and more particularly to wireless LAN sensing. [Background technology]

[0002] WLAN (wireless local area network) has been improved in various ways. For example, IEEE802.11bf wireless LAN sensing is the first standard that combines communication and radar technologies. The demand for unlicensed frequencies is rapidly increasing in daily life and industry, but new supply of frequencies is limited, so the development of communication and radar fusion technology is a very favorable direction in terms of increasing frequency utilization efficiency. Existing sensing technologies have been developed that use wireless LAN signals to detect movement behind walls, and radar technologies that use FMCW (Frequency Modulated Continuous Wave) signals in the 70 GHz band to detect movement inside vehicles, but this is significant in that it will take sensing performance to the next level in conjunction with IEEE802.11bf standardization. In particular, the importance of protecting private life is increasingly emphasized in modern society, and there are high expectations for the development of wireless LAN sensing technology, which has more legal freedom in the matter of infringing on private life, unlike CCTV.

[0003] Meanwhile, the overall radar market across the board, including automobiles, defense, industry, and lifestyle, is predicted to grow at a CAGR of approximately 5% until 2025, with lifestyle sensors in particular expected to grow at a CAGR of 70%. WLAN sensing technology can be applied to a wide range of real-life applications, including motion detection, respiration monitoring, positioning / tracking, fall detection, baby detection in vehicles, appearance / proximity recognition, personal identification, body movement recognition, and behavior recognition, and is expected to promote the growth of related new businesses and contribute to improving corporate competitiveness.

[0004] For example, the wireless LAN (WLAN) sensing proposed in this specification can be used to sense the movement or gesture of an object (person or thing). Specifically, a WLAN STA can sense the movement or gesture of an object (person or thing) based on measurement results for various types of frames / packets designed for WLAN sensing.

[0005] When sensing measurements are performed by STAs other than the AP, definition of peer-to-peer (P2P)-based signal transmission and reception between STAs may be required, although current WLAN standards do not support P2P-based signal transmission and reception. Summary of the Invention [Means for solving the problem]

[0006] This specification proposes a new signal transmission / reception procedure between STAs when sensing measurement initiated by a STA other than the AP is performed. According to one embodiment of this specification, a sensing measurement procedure is proposed in which a STA other than the AP transmits a sensing start frame to the AP, whereby the AP requests a responder STA to transmit an NDP frame. According to another embodiment of this specification, a method for configuring frames transmitted and received in the procedure is proposed. Effect of the Invention

[0007] According to this specification, a signal transmission / reception procedure without P2P operation is newly proposed when a sensing procedure is initiated by a STA other than an AP, thereby reducing the overall complexity of the sensing procedure, such as sensing measurement. [Brief description of the drawings]

[0008] [Figure 1]An example of a WLAN sensing scenario utilizing multiple sensing transmitters is shown. [Diagram 2] An example of a WLAN sensing scenario utilizing multiple sensing receivers is shown. [Diagram 3] 1 shows an example of a wireless LAN sensing procedure. [Figure 4] This is an example of classifying wireless LAN sensing. [Diagram 5] This shows indoor positioning using CSI-based wireless LAN sensing. [Figure 6] This is an example of a wireless LAN sensing device. [Figure 7] A simplified diagram showing the PPDU structure supported in an 802.11ay wireless LAN system. [Figure 8] 2 shows an example of a sensing frame format. [Figure 9] 13 shows another example of a sensing frame format. [Figure 10] 13 shows another example of a sensing frame format. [Figure 11] 13 shows another example of a sensing frame format. [Figure 12] 13 shows another example of a sensing frame format. [Figure 13] 13 shows another example of a sensing frame format. [Figure 14] 1 shows a modified example of the transmitting device and / or the receiving device of the present specification. [Figure 15] 13 shows an example of a measurement sequence when an initiator non-AP STA performs the role of a transmitter. [Figure 16] An example of a measurement sequence / measurement order when an initiator non-AP STA performs the role of a receiver is shown. [Figure 17] 4 is a flow diagram of an example of a method performed by an initiating device in a wireless LAN system. [Figure 18]4 is a flow diagram of an example of a method performed by an AP in a wireless LAN system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] As used herein, "A or B" can mean "A only," "B only," or "both A and B." In other words, as used herein, "A or B" can be interpreted as "A and / or B." For example, as used herein, "A, B or C" can mean "A only," "B only," "C only," or "any combination of A, B and C."

[0010] As used herein, a slash ( / ) or a comma can mean "and / or." For example, "A / B" can mean "A and / or B." Thus, "A / B" can mean "A only," "B only," or "both A and B." For example, "A, B, C" can mean "A, B, or C."

[0011] In this specification, "at least one of A and B" can mean "A only," "B only," or "both A and B." In addition, in this specification, the expressions "at least one of A or B" and "at least one of A and / or B" can be interpreted similarly to "at least one of A and B."

[0012] In addition, in this specification, "at least one of A, B and C" can mean "A only," "B only," "C only," or "any combination of A, B and C." Furthermore, "at least one of A, B or C" and "at least one of A, B and / or C" can mean "at least one of A, B and C."

[0013] In this specification, technical features individually described in one drawing may be embodied individually or simultaneously.

[0014] The following example of the present specification may be applied to various wireless communication systems. For example, the following example of the present specification may be applied to a wireless local area network (WLAN) system. For example, the present specification may be applied to the IEEE 802.11ad standard or the IEEE 802.11ay standard. In addition, the present specification may be applied to the newly proposed WLAN sensing standard or the IEEE 802.11bf standard.

[0015] In order to explain the technical features of the present specification, technical features to which the present specification can be applied will be explained below.

[0016] WLAN sensing technology is a type of radar technology that can be implemented without standards, but it is believed that more powerful performance can be achieved through standardization. The IEEE802.11bf standard defines devices participating in WLAN sensing by function as shown in the table below. Depending on the function, they can be classified into devices that start WLAN sensing and devices that participate in it, devices that send sensing PPDU (Physical Layer Protocol Data Unit) and devices that receive it, etc.

[0017] [Table 1]

[0018] FIG. 1 shows an example of a WLAN sensing scenario using multiple sensing transmitters.

[0019] FIG. 2 shows an example of a WLAN sensing scenario utilizing multiple sensing receivers.

[0020] Figures 1 and 2 show sensing scenarios based on the functions and arrangement of a WLAN sensing device. In an environment assuming one sensing initiation device and multiple sensing participation devices, Figure 1 shows a scenario using multiple sensing PPDU transmission devices, and Figure 2 shows a scenario using multiple sensing PPDU reception devices. Assuming that the sensing PPDU reception device includes a sensing measurement signal processing device, in the case of Figure 2, an additional procedure is required to transmit (feed back) the sensing measurement results to the sensing initiation device (STA5).

[0021] FIG. 3 shows an example of a wireless LAN sensing procedure.

[0022] The procedure for WLAN sensing includes discovery, negotiation, measurement exchange, tear down, etc. between a WLAN sensing initiating device and a joining device. Discovery is a process of determining the sensing capability of a WLAN device, negotiation is a process of determining sensing parameters between a sensing initiating device and a joining device, measurement exchange is a process of transmitting a sensing PPDU to transmit a sensing measurement result, and tear down is a process of terminating the sensing procedure.

[0023] Figure 4 shows an example of classification of wireless LAN sensing.

[0024] WLAN sensing can be classified into CSI-based sensing, which uses channel state information of a signal that leaves a transmitter, passes through a channel, and reaches a receiver, and radar-based sensing, which uses a signal that is reflected by an object and received. Each sensing technology can be further classified into a method in which the sensing transmitter directly participates in the sensing process (coordinated CSI, active radar) and a method in which the sensing transmitter does not participate in the sensing process, i.e., there is no dedicated transmitter that participates in the sensing process (un-coordinated CSI, passive radar).

[0025] Figure 5 shows indoor positioning using CSI-based WLAN sensing.

[0026] FIG. 5 shows the application of CSI-based WLAN sensing to indoor positioning. The angle of arrival and time of arrival are obtained using the CSI, and indoor positioning information can be obtained by converting these into Cartesian coordinates.

[0027] FIG. 6 shows an example of a wireless LAN sensing device.

[0028] FIG. 6 shows a WLAN sensing device implemented using MATLAB® Toolbox, Zynq, and USRP. The MATLAB Toolbox generates an IEEE802.11ax WLAN signal, and the Zynq SDR (Software Defined Radio) generates an RF signal. The signal that passes through the channel is received by the USRP SDR and sensing signal processing is performed by the MATLAB Toolbox. Here, one reference channel (a channel that can be received directly from the sensing transmitter) and one surveillance channel (a channel that can be received after being reflected by an object) are assumed. As a result of analysis using the WLAN sensing device, unique characteristics that can distinguish movements and body movements were obtained.

[0029] Currently, the IEEE802.11bf WLAN sensing standardization is in the early development stage, and cooperative sensing technology to improve sensing accuracy will be given importance in the future. It is expected that key standardization themes for cooperative sensing will be sensing signal synchronization technology, CSI management and utilization technology, sensing parameter negotiation and sharing technology, and scheduling technology for CSI generation. Other major topics to be considered include long-distance sensing technology, low-power sensing technology, sensing security, and privacy protection technology.

[0030] IEEE802.11bf wireless LAN sensing is a type of radar technology that utilizes wireless LAN signals that are available anytime and anywhere. The following table shows some representative IEEE802.11bf usage cases, which can be used in a wide range of real-life applications, such as indoor detection, motion recognition, health management, 3D vision, and vehicle interior detection. Since it is mainly used indoors, the operating range is approximately 10 to 20 meters, and the distance accuracy does not exceed a maximum of 2 meters.

[0031] [Table 2-1]

[0032] [Table 2-2]

[0033] [Table 2-3]

[0034] [Table 2-4]

[0035] In IEEE802.11, there is ongoing discussion on technology that uses Wi-Fi signals in various bands to sense the movements and gestures of objects (people or things). For example, it is possible to sense the movements and gestures of objects (people or things) using Wi-Fi signals in the 60GHz band (e.g., 802.11ad or 802.11ay signals). It is also possible to sense the movements and gestures of objects (people or things) using Wi-Fi signals in the sub-7GHz band (e.g., 802.11ac, 802.11ax, 802.11be signals).

[0036] Hereinafter, we will explain the technical features of PPDU according to the 802.11ay standard, which is one of the Wi-Fi signals in the 60 GHz band that can be used for wireless LAN sensing.

[0037] FIG. 7 is a simplified diagram showing a PPDU structure supported in an 802.11ay wireless LAN system.

[0038] As shown in FIG. 7, PPDU formats applicable to 802.11ay systems may include L-STF, L-CEF, L-Header, EDMG-Header-A, EDMG-STF, EDMG-CEF, EDMG-Header-B, Data, and TRN fields, and the above fields may be selectively included depending on the type of PPDU (e.g., SU PPDU, MU PPDU, etc.).

[0039] Here, the portion including the L-STF, L-CEF, and L-Header fields can be named the non-EDMG portion, and the remaining portion can be named the EDMG portion. Also, the L-STF, L-CEF, L-Header, and EDMG-Header-A fields can be named pre-EDMG modulated fields, and the remaining portion can be named EDMG modulated fields.

[0040] The EDMG-Header-A field contains information required to demodulate an EDMG PPDU. The definition of the EDMG-Header-A field is the same as that of an EDMG SC mode PPDU and an EDMG OFDM mode PPDU, but is different from that of an EDMG control mode PPDU.

[0041] The structure of the EDMG-STF is determined by the number of contiguous 2.16 GHz channels on which the EDMG PPDU is transmitted and the STS Index of the i-th space-time stream STS For a single space-time stream EDMG PPDU transmission using EDMG SC mode over a single 2.16 GHz channel, the EDMG-STF field is not present. For EDMG SC transmission, the EDMG-STF field shall be modulated using pi / (2-BPSK).

[0042] The structure of the EDMG-CEF is determined by the number of contiguous 2.16 GHz channels on which the EDMG PPDUs are transmitted and the number of space-time streams iSTS For a single space-time stream EDMG PPDU transmission using EDMG SC mode over one 2.16 GHz channel, the EDMG-CEF field is not present. For EDMG SC transmission, the EDMG-CEF field shall be modulated using pi / (2-BPSK).

[0043] The (legacy) preamble portion of the PPDU can be used for packet detection, automatic gain control (AGC), frequency offset estimation, synchronization, indication of modulation (SC or OFDM), and channel estimation. The preamble format can be common to OFDM packets and SC packets. In this case, the preamble can be composed of a short training field (STF) and a channel estimation (CE) field located after the STF field.

[0044] An example of a sensing frame format proposed for 60 GHz band sensing or wireless LAN (WLAN) sensing will be described below. A frame, packet, and / or data unit used for sensing or wireless LAN (WLAN) sensing proposed in this specification may be called a sensing frame. The sensing frame may be called various names such as a sensing measurement frame, a sensing operation frame, and / or a measurement frame.

[0045] FIG. 8 shows an example of a sensing frame format.

[0046] The Wi-Fi sensing signal can be transmitted and received between the AP / STA and the STA for channel estimation using a 60 GHz Wi-Fi signal. In this case, in order to support backward compatibility with the existing 60 GHz Wi-Fi signals 802.11ad and 802.11ay, the sensing frame can be configured in a frame format as shown in FIG. 8 including a non-EDMG preamble portion (i.e., L-STF, L-CEF, and L-Header).

[0047] As shown in FIG. 8, the sensing frame may be composed of L-STF, L-CEF, L-Header, EDMG-Header A, EDMG-STF, and EDMG-CEF.

[0048] That is, the sensing frame can be configured without including a data field, unlike the existing EDMG frame, in order to estimate channel changes between P2P (Point to Point) or P2MP (Point to Multipoint) and perform sensing for a STA or object.

[0049] Since the EDMG frame can be transmitted using one or more channels (i.e., multiple channel bandwidths) in the 60 GHz band, the sensing frame includes an EDMG-STF and an EDMG-CEF field as shown in FIG.

[0050] Using the EDMG-STF and EDMG-CEF fields, the STA / AP can perform accurate channel information measurement in the sensing transmission / reception bandwidth (BW).

[0051] Information on the BW used for the sensing can be transmitted via EDMG-header A, and at this time, it can be transmitted using various BWs as follows.

[0052] [Table 3]

[0053] FIG. 9 shows another example of the sensing frame format.

[0054] Unlike the above, the sensing signal can be transmitted using only a fixed BW (e.g., 2.16 GHz), in which case additional AGC is not required and EDMG-STF can be omitted. Therefore, when sensing is performed using only a determined BW, the EDMG-STF can be omitted and a sensing frame format can be configured as shown in Fig. 9. Also, since only a determined BW is used, the EDMG-header does not include a BW field during sensing, unlike conventional methods.

[0055] FIG. 10 shows another example of the sensing frame format.

[0056] 802.11ay transmission at 60 GHz basically transmits a signal using beamforming, and at this time, in order to set an optimal beam between Tx and Rx, an antenna weight vector (AWV) for the Tx antenna and the Rx antenna is set using a training (i.e., TRN) field. Therefore, since the sensing frame transmits a signal using a previously determined AWV, it is difficult to accurately reflect changed channel conditions. Therefore, in order to more accurately measure changes in the channel, the sensing frame can be configured to include a TRN field as follows, and at this time, information on the channel can be measured via the TRN field.

[0057] In Fig. 10, the sensing frame does not include a data field, and since channel measurement for sensing is performed using TRN, the EDMG-CEF field for channel estimation can be omitted. Therefore, the sensing frame format can be configured as shown in Fig. 11.

[0058] FIG. 11 shows another example of the sensing frame format.

[0059] Below, we will explain the technical features of PPDU using sub-7GHz Wi-Fi signals that can be used for wireless LAN sensing.

[0060] An example of a sensing frame format proposed for sensing in the sub-7 GHz band or wireless LAN (WLAN) sensing will be described below. For example, for sensing according to this specification, various PPDUs in the 2.4 GHz, 5 GHz, and 6 GHz bands can be used as the sensing frame. For example, PPDUs according to the IEEE 802.11ac, 802.11ax, and / or 802.11be standards can be used as the sensing frame.

[0061] FIG. 12 shows another example of the sensing frame format.

[0062] The sensing frame according to the present specification may use only some of the fields shown in Fig. 12. For example, the Data field shown in Fig. 12 may be omitted. Additionally or alternatively, the VHT-SIG B and / or HE-SIG B fields shown in Fig. 12 may be omitted.

[0063] FIG. 13 shows another example of the sensing frame format.

[0064] The sensing frame according to the present specification may use only some of the fields of the Extreme High Throughput (EHT) PPDU shown in Fig. 13. For example, the Data field shown in Fig. 13 may be omitted.

[0065] The PPDU in FIG. 13 may indicate some or all of the PPDU types used in the EHT system. For example, the example in FIG. 13 may be used for both the single-user (SU) mode and the multi-user (MU) mode. In other words, the PPDU in FIG. 13 is a PPDU for one receiving STA or multiple receiving STAs. When the PPDU in FIG. 13 is used for the Trigger-based (TB) mode, the EHT-SIG in FIG. 13 may be omitted. In other words, a STA that receives a Trigger frame for Uplink-MU (UL-MU) communication may transmit a PPDU in the example in FIG. 13 with the EHT-SIG omitted.

[0066] The subcarrier spacing of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-SIG fields in Fig. 13 is determined to be 312.5 kHz, and the subcarrier spacing of the EHT-STF, EHT-LTF, and Data fields is determined to be 78.125 kHz. That is, the tone index (or subcarrier index) of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-SIG fields can be represented in units of 312.5 kHz, and the tone index (or subcarrier index) of the EHT-STF, EHT-LTF, and Data fields can be represented in units of 78.125 kHz.

[0067] In the PPDU of FIG. 13, L-LTF and L-STF are the same as conventional fields.

[0068] The L-SIG field in FIG. 13 may include, for example, 24-bit bit information. For example, the 24-bit information may include a 4-bit Rate field, a 1-bit Reserved bit, a 12-bit Length field, a 1-bit Parity bit, and 6-bit Tail bits. For example, the 12-bit Length field may include information regarding the length or time duration of the PPDU. For example, the value of the 12-bit Length field may be determined based on the type of the PPDU. For example, if the PPDU is a non-HT, HT, VHT PPDU, or an EHT PPDU, the value of the Length field may be determined to be a multiple of 3. For example, if the PPDU is a HE PPDU, the value of the Length field may be determined to be a "multiple of 3+1" or a "multiple of 3+2". In other words, for a non-HT, HT, VHT PPDU, or EHT PPDU, the value of the Length field may be determined to be a multiple of 3, and for a HE PPDU, the value of the Length field may be determined to be a "multiple of 3 + 1" or a "multiple of 3 + 2".

[0069] The transmitting STA can generate a RL-SIG that is generated the same as the L-SIG. BPSK modulation can be applied to the RL-SIG. Based on the presence of the RL-SIG, the receiving STA can know that the received PPDU is a HE PPDU or an EHT PPDU.

[0070] A Universal SIG (U-SIG) can be inserted after the RL-SIG in Figure 13. The U-SIG can be called various names such as a first SIG field, a first SIG, a first type SIG, a control signal, a control signal field, a first (type) control signal, etc.

[0071] The U-SIG may include N-bit information and may include information for identifying the type of EHT PPDU. For example, the U-SIG may be configured based on two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG may have a duration of 4us. Each symbol of the U-SIG may be used to transmit 26-bit information. For example, each symbol of the U-SIG may be transmitted and received based on 52 data tones and 4 pilot tones.

[0072] The U-SIG can be configured in 20 MHz units. For example, when an 80 MHz PPDU is configured, the U-SIG can be duplicated. That is, the same four U-SIGs can be included in the 80 MHz PPDU. PPDUs that exceed the 80 MHz bandwidth can contain different U-SIGs.

[0073] The EHT-SIG of FIG. 13 may include control information for a receiving STA. For example, the EHT-SIG may include a common field and a user-specific field. The common field may be omitted, and the number of the user-specific fields may be determined based on the number of users. The common field may include RU allocation information. The RU allocation information may mean information on the location of RUs to which multiple users (i.e., multiple receiving STAs) are assigned. The RU allocation information may be configured in 9-bit units. The user-specific field may include information for decoding at least one RU identified via the common field (e.g., STA ID information assigned to the corresponding RU, MCS index applied to the corresponding RU, LDPC / BCC coding type information applied to the corresponding RU, etc.).

[0074] The EHT-STF of Figure 13 can be used to improve automatic gain control estimation in a multiple input multiple output (MIMO) environment or an OFDMA environment, and the EHT-LTF of Figure 13 can be used to estimate a channel in a MIMO environment or an OFDMA environment.

[0075] FIG. 14 shows a modified example of the transmitting device and / or the receiving device of this specification.

[0076] The device in Fig. 14 may be referred to by various names such as a mobile terminal, a wireless device, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), a mobile subscriber unit, or simply a user. In addition, the device in Fig. 14 may be referred to by various names such as a base station, a Node-B, an access point (AP), a repeater, a router, a relay, etc.

[0077] The processor 610 of FIG. 14 may direct and control operations performed by the STA, transmitting STA, receiving STA, AP, non-AP, and / or user-STA according to the present specification. For example, the processor 610 may receive signals via the transceiver 630, process the received signals, generate transmission signals, and perform control for signal transmission. The illustrated processor, memory, and transceiver may each be embodied in a separate chip, or at least two or more blocks / functions may be embodied in one chip.

[0078] 14 may store signals received via the transceiver 630 (i.e., received signals) and may store signals transmitted via the transceiver 630 (i.e., transmitted signals). Also, the memory 620 of FIG. 14 may store signals received via the transceiver 630 (i.e., received signals) and may store signals transmitted via the transceiver 630 (i.e., transmitted signals).

[0079] 14, a power management module 611 manages power to the processor 610 and / or the transceiver 630. A battery 612 provides power to the power management module 611. A display 613 outputs results processed by the processor 610. A keypad 614 receives inputs used by the processor 610. The keypad 614 can be displayed on the display 613. A SIM card 615 is an integrated circuit used to securely store an international mobile subscriber identity (IMSI) and associated keys used in identifying and authenticating a subscriber on mobile phone devices such as mobile phones and computers.

[0080] 14, the speaker 640 can output sound-related results processed by the processor 610. The microphone 641 can receive sound-related inputs used by the processor 610.

[0081] In the following, the method proposed herein is explained.

[0082] In order to improve the accuracy and resolution of WLAN sensing, WLAN sensing using signal transmission / reception channels between multiple sensing STAs is considered. The sensing STAs may include STAs and APs. Therefore, in order to efficiently perform WLAN sensing using signal transmission / reception channels between a sensing initiator and multiple sensing responders, channel estimation for each transmission / reception channel may be required. This specification proposes a channel sounding method for efficiently performing channel measurement for multiple transmission / reception channels used for sensing.

[0083] In WLAN sensing, an initiator can measure channels using transmission and reception channels with multiple responders. In this case, the initiator can perform sensing operations with the following roles:

[0084] 1. Initiator & transmitter: This may refer to the case where the initiator performs the role of a transmitter that transmits a measurement frame for channel estimation to a sensing responder.

[0085] 2. Initiator & Receiver: This may refer to a case where an initiator requests a responder to transmit a measurement frame for channel estimation and receives the measurement frame.

[0086] The sensing initiator defined above is an AP or a non-AP STA. This specification proposes a sensing measurement procedure when the sensing initiator is a non-AP STA.

[0087] As an example, a non-AP STA that is an initiator may have a role of a transmitter. Figure 15 shows an example of a measurement sequence when a non-AP STA that is an initiator performs a role of a transmitter.

[0088] 15, an initiator acting as a transmitter can transmit a sensing request frame to a responder 1 (AP). Here, the initiator is a non-AP STA. The responder 1 can transmit a response frame to the sensing request frame to the initiator.

[0089] Thereafter, the responder 1 can transmit a sensing poll frame. Here, the responder n can transmit a response frame to the sensing poll frame to the responder 1.

[0090] After that, the responder 1 can send a trigger frame. The initiator can send an NDP frame based on the trigger frame. The sending of the NDP frame is an action triggered by the trigger frame.

[0091] Thereafter, the responder 1 may transmit a feedback request frame to the responder n. In response to the feedback request frame, the responder n may transmit a feedback frame to the responder 1. The responder 1 may transmit a sensing feedback frame to the initiator.

[0092] In another embodiment, the responder 1 may transmit a sensing feedback frame to the initiator after receiving a feedback request frame from the initiator.

[0093] As shown in FIG. 15, when an initiator non-AP STA performs the role of a transmitter, some or all of the following rules may be applied.

[0094] 1. STAs / APs participating in sensing can exchange sensing roles and information regarding the STAs through negotiation for sensing operations.

[0095] 2. To start a sensing measurement, an initiator non-AP STA can send a sensing request frame or an initial sensing request frame to an AP participating in sensing.

[0096] 2.A. The request frame transmitted by the non-AP STA may include some or all of the following information:

[0097] 2. Information for Ai sensing responder STAs

[0098] 2. Ai1. The information is STA-ID (identifier) ​​information for the STA participating in sensing, which is learned through negotiation or discovery procedures.

[0099] 2.A.ii. Sensing role indication

[0100] 2.A.ii.1. The instruction is information as to whether the initiator will perform a sender role or a receiver role.

[0101] The indication may be composed of 1 bit. In this case, for example, if the initiator plays the role of a sender, the indication may be set to 0, and if the initiator plays the role of a receiver, the indication may be set to 1.

[0102] 2.A.iii. Information on TXOP or sensing duration

[0103] 2.A.iii.1. The information is information regarding the time for exchanging sensing measurement frames.

[0104] Based on the information, the third party STA can perform network allocation vector (NAV) configuration, so that sensing operations can be protected.

[0105] 2.A.iii.3. The TXOP is a TXOP that a non-AP STA requests from an AP for sensing or a TXOP determined during sensing negotiation.

[0106] 2.A.iii.3.A. In the case of a TXOP determined during negotiation, the information can be shared with all STAs participating in sensing, and all STAs participating in sensing can use the information for sensing operations.

[0107] 2.A.iii.4. The information may consist of 7 bits.

[0108] 2.A.iv. Information on Sensing Burst Configuration

[0109] The sensing period may be composed of a number of sensing bursts, and the information may include information regarding the number of the bursts and the size of the bursts.

[0110] 2.AvSensing operation bandwidth information

[0111] 2.Av1. The information is for the bandwidth over which the sensing measurement is performed, where the information can be configured with 3 bits to indicate 20, 40, 80, 160 and / or 320 MHz.

[0112] 2. B. The AP can transmit a response frame to the non-AP STA in response to the request frame transmitted by the non-AP STA. In this case, the response frame can include the following information:

[0113] 2.BiSensing Bandwidth (Sensing BW)

[0114] 2.B.ii. TXOP for sensing

[0115] 2.B.iii.Sensing confirmation

[0116] 2.C. Through the sensing request frame and response frame exchanged between the non-AP STA and the AP, the third party STA sets the NAV and does not perform channel access while the sensing operation is being performed.

[0117] 3. The AP that sent the sensing responder / response frame to the initiator can send a sensing poll frame or a sensing trigger frame to the sensing STAs that have the sensing capability identified through the negotiation / sensing request frame to determine whether they can perform sensing.

[0118] 3.A. The sensing poll frame or sensing trigger frame may include one or more of the following information:

[0119] 3. AiSTA-ID: ID for sensing STA

[0120] 3.A.ii. Spatial stream (SS) allocation sensing: Information on spatial streams allocated to a STA during sensing.

[0121] 3.A.iii.BW: Sensing Bandwidth

[0122] 3.A.iv. Sensing measurement indication

[0123] 3.Av sensing channel confirmation request

[0124] The information for the sensing channel confirmation request may indicate whether transmission / reception is possible for the sensing bandwidth. The information may be configured in units of 20 MHz. Also, the information may be configured as a bitmap.

[0125] 3.A.vi. Sensing feedback request availability

[0126] 3.A.vi.1. The information on whether or not sensing feedback is requested is information indicating whether or not measurement feedback needs to be transmitted.

[0127] 3.A.vii. Allocation information for response frames

[0128] 3.A.vii.1. The information may include RU allocation information for transmission of the response frame.

[0129] 4. As described above, a sensing responder STA that receives a sensing poll / polling frame from the AP can transmit a response frame to the AP.

[0130] 4.A. The response frame can be transmitted to the AP sequentially at SIFS intervals, or the response frame can be transmitted after a SIFS interval after receiving the request frame using a bandwidth or resource unit allocation (RU) allocated by the AP.

[0131] 5. Through the response frame, the AP can know which STAs will participate in the actual sensing measurement. After receiving the response frame, the AP can transmit a trigger frame to perform the sensing measurement after a SIFS has elapsed.

[0132] 5.A. In the above, the trigger frame transmitted by the AP can be used to request the initiator, a non-AP STA, to transmit a null data packet (NDP) frame.

[0133] 5. The trigger frame transmitted by the AP may include the following information:

[0134] 5. Ai1. ID of initiator non-AP STA

[0135] 5. Ai2.RU allocation or allocated subchannel info

[0136] 5. Ai3. Information on the number of spatial streams

[0137] 5. Ai4. Number of LTFs (long training fields) or LTF repetitions

[0138] 5. Size of Ai5.LTF

[0139] 5.Ai6.Sensing measurement indication or NDP transmission indication

[0140] 5.Ai6.A. The information is information requesting the initiator to send an NDP frame.

[0141] 5.Ai6.B. The responder knows via the information that the transmission of NDP frames will begin.

[0142] 5.B. The trigger frame can also be used to inform the sensing responder that transmission of NDP frames is to begin.

[0143] 6. The initiator that receives the trigger frame for transmitting the NDP frame from the AP can transmit an NDP frame for sensing measurement. The NDP frame can be transmitted after SIFS has elapsed after receiving the trigger frame.

[0144] 7. After the initiator sends the NDP frame, the AP can send a feedback request frame to the responder STA for channel measurement feedback.

[0145] 7.A. The feedback request frame may be transmitted SIFS after the transmission of the NDP frame.

[0146] 7.B. The feedback request frame may include some or all of the following information:

[0147] 7.Bi feedback type

[0148] 7.Bi1. The feedback type may include CQI (channel quality indicator), RSSI (Received Signal Strength Indicator), angle, compressed, etc.

[0149] 7.B.ii. Codebook size

[0150] 7.B.ii.1. The information is regarding the magnitude of the information being fed back.

[0151] 7.B.iii. Feedback resolution

[0152] 7.B.iii.1. The information is in units of channel measurement (e.g., n g = 1, 2, 4, 8, 16, etc.).

[0153] 7.B.iv.RU Allocation

[0154] 7.B.iv.1. The information may include information for the RU to use when performing measurement information feedback.

[0155] 7.Bv spatial stream (SS)

[0156] 7.Bv1. The information may include information regarding the number of assigned SSs and the start of the assigned SSs.

[0157] 7.B.vi.MCS(modulation and coding scheme)

[0158] 7.B.vi.1. The information may include MCS information used in the feedback information.

[0159] 7.B.vii. Encoding

[0160] 7.B.vii.1. The information may indicate encoding information (BCC or LDPC) for the feedback information.

[0161] 8. After transmitting the feedback request frame, the AP that receives feedback information from the responder STA can transmit the channel measurement information received from other responders to the initiator.

[0162] 8.A. After receiving the feedback request frame, the responder STA can simultaneously transmit feedback information using the assigned RU after SIFS has elapsed.

[0163] 8.B. Alternatively, the responder may transmit feedback information to the AP sequentially at SIFS intervals.

[0164] 8.C. Now, after receiving feedback information from all responder STAs that participated in sensing, the AP can transmit all feedback information to the initiator after a SIFS has elapsed.

[0165] 8.D. Alternatively, the AP may send all feedback information to the initiator after receiving a feedback request frame from the initiator.

[0166] 9. Although it has been assumed above that the procedure for sensing measurement is performed in one TXOP, the measurement may also be performed in multiple TXOPs.

[0167] 9.A. As an example, the TXOP for sensing feedback can be configured separately.

[0168] 9.B. As another example, the TXOP for each of the sensing request & response, sensing polling and NDP transmission, and feedback procedures can be set independently.

[0169] Alternatively, the initiator non-AP STA may act as a receiver. Figure 16 shows an example of a measurement sequence when the initiator non-AP STA acts as a receiver.

[0170] When the initiator non-AP STA performs the role of a receiver, some or all of the following rules may apply.

[0171] 10. The same sensing procedures as described in the above rules 1 to 4 can be applied. For example, referring to Fig. 16, an initiator, which is a non-AP STA, can transmit a sensing request frame to an AP, responder_1. In this case, the AP that receives the request frame can transmit a response frame to the initiator after a SIFS has elapsed.

[0172] 10.A. The request and response frames may contain the information suggested in rules 1 and 2 above.

[0173] 11. After transmitting the response frame, the AP may transmit a sensing poll / polling frame. In this case, each frame may be configured as described in the above rules 3 and 4. Also, frame exchange between the AP and the responder STA may be performed.

[0174] 12. As shown in FIG. 16, an AP that has identified an actual sensing responder participating in sensing through a response frame received from a responder STA can send a trigger frame to the responder STA to request the responder STA to send an NDP frame.

[0175] 12.A. The trigger frame for requesting transmission of the NDP frame may include the following information:

[0176] 12. AiNDP transmission request indication

[0177] 12.A.ii. Responder STA's ID information

[0178] 12.A.ii.1. The information may include ID information for the STA transmitting the NDP frame.

[0179] 12.A.iii.LTF Information

[0180] 12.A.iii.1. The information may indicate the magnitude or type of LTF (e.g., 1x, 2x, 4x).

[0181] 12.A.iii.2. The information may include information for LTF repetitions.

[0182] 12.A.iii.3. The information may indicate the number of LTF symbols.

[0183] 12.A.iv. Number of spatial streams (Nss)

[0184] 12.A.iv.1. The information may indicate the assigned Nss per STA.

[0185] 12.A.iv.2. The information may inform the total Nss.

[0186] 12. Av bandwidth or RU / subchannel allocation for NDP frames

[0187] 12.Av1. The information may include information on bandwidth and RU / subchannel for transmission of NDP frames.

[0188] 13. After receiving the trigger frame requesting the transmission of the NDP frame, the responder STA can transmit an NDP frame to the initiator after a SIFS has elapsed.

[0189] 13.A. Now, the AP can also send an NDP frame to the initiator.

[0190] 13.B. The NDP frames can be transmitted simultaneously, or the NDP frames can be transmitted sequentially to responder STAs at SIFS intervals.

[0191] An example of a sensing procedure performed in a wireless LAN system according to some embodiments of the present disclosure will now be described. FIG 17 is a flow diagram of an example of a method performed by an initiator device in a wireless LAN system.

[0192] 17, an initiating device transmits a sensing start frame to an AP (S1710). Here, the initiating device is a non-AP station (STA) that is not an AP. Also, the sensing start frame is the same as the sensing request frame of FIG. 15 and / or FIG. 16. In response to the sensing start frame, the initiating device receives a sensing response frame from the AP (S1720).

[0193] Thereafter, the initiating device performs one of a transmitter operation and a receiver operation based on the sensing role of the initiating device (S1730). When the initiating device performs the transmitter role, the procedure described with reference to FIG. 15 may be executed. Specifically, based on the initiating device performing the transmitter role, the initiating device may transmit a first NDP frame. Here, the first NDP frame is a frame transmitted based on a trigger frame received by the initiating device from the AP.

[0194] Also, if the initiating device performs the role of a receiver, the procedure described with reference to Figure 16 may be executed. For example, based on the initiating device performing the role of a receiver, the initiating device may receive a second NDP frame from one or more responding devices.

[0195] FIG. 18 is a flow diagram of an example of a method performed by an AP in a wireless LAN system.

[0196] 18, an AP receives a sensing start frame from an initiating device (S1810). Here, the initiating device is a non-AP STA. The AP transmits a sensing response frame to the initiating device in response to the start frame (S1820).

[0197] The AP transmits a sensing poll frame (S1830) and receives sensing poll response frames from one or more responding devices in response to the sensing poll frame (S1840).

[0198] The AP transmits a trigger frame to the initiator device and one of the one or more responder devices based on the role of the initiator device (S1850), where the role of the initiator device is a transmitter or a receiver.

[0199] An example in which the role of the initiator device is a transmitter is the same as the example of FIG. 15. Specifically, based on the initiator device performing the role of a transmitter, the AP may transmit the trigger frame to the initiator device. Here, the trigger frame is a frame that triggers the transmission of an NDP frame of the initiator device. Also, the AP may transmit a feedback request frame to the one or more responding devices. Also, the AP may receive a feedback response frame as a response to the feedback request frame from the one or more responding devices. Here, the feedback response frame may include sensing measurement information for sensing measurements performed by the one or more responding devices. Also, the AP may transmit a feedback frame including the sensing measurement information to the initiator device based on the feedback response frame.

[0200] Alternatively, an example in which the role of the initiating device is a receiver is the same as the example of FIG. 16. Specifically, based on the initiating device performing the role of a receiver, the AP may transmit the trigger frame to the one or more responding devices. Here, the trigger frame is a frame that triggers the transmission of an NDP frame of the one or more responding devices. In this case, the NDP frame is a frame transmitted to the initiating device. The initiating device may perform sensing measurement based on the NDP frame.

[0201] It is obvious that the configuration / proposed method described through Figures 15 and 16 can be applied to Figures 17 and / or 18. Therefore, a duplicated description will be omitted.

[0202] The technical features of the present specification described above can be applied to various applications and business models. For example, the technical features described above can be applied to wireless communication in devices that support artificial intelligence (AI).

[0203] Artificial intelligence refers to the field that studies artificial intelligence or the methodology that can create it, and machine learning refers to the field that defines various problems that are dealt with in the field of artificial intelligence and studies the methodology to solve them. Machine learning can also be defined as an algorithm that improves the performance of any task through continuous experience with that task.

[0204] An artificial neural network (ANN) is a model used in machine learning, and can refer to any model with problem-solving capabilities that is composed of artificial neurons (nodes) that form a network through synaptic connections. An artificial neural network can be defined by the connection pattern between neurons in different layers, a learning process that updates model parameters, and an activation function that generates output values.

[0205] An artificial neural network can have an input layer, an output layer, and optionally one or more hidden layers. Each layer includes one or more neurons, and an artificial neural network can include synapses connecting the neurons. In an artificial neural network, each neuron can output a function value of an activation function for the input signal, weights, and biases input via synapses.

[0206] Model parameters are parameters that are determined through learning, and include weights of synaptic connections and biases of neurons, etc. Hyperparameters are parameters that must be set before learning in a machine learning algorithm, and include the learning rate, number of iterations, mini-batch size, initialization function, etc.

[0207] The objective of training an artificial neural network can be regarded as determining model parameters that minimize a loss function. The loss function can be used as an index for determining optimal model parameters during the training process of an artificial neural network.

[0208] Depending on the learning method, machine learning can be classified into supervised learning, unsupervised learning, and reinforcement learning.

[0209] Supervised learning refers to a method of training an artificial neural network when a label for training data is given, and the label can mean the correct answer (or result value) that the artificial neural network should infer when training data is input to the artificial neural network. Unsupervised learning can mean a method of training an artificial neural network when no label for training data is given. Reinforcement learning can mean a learning method of training an agent defined in an environment to select an action or action sequence that maximizes cumulative compensation in each state.

[0210] Machine learning realized by a deep neural network (DNN) with multiple hidden layers in an artificial neural network is sometimes called deep learning, and deep learning is a part of machine learning. In the following, machine learning is used to include deep learning.

[0211] Furthermore, the above-described technical features can be applied to wireless communication of a robot.

[0212] A robot can mean a machine that automatically processes or operates a given task using its own capabilities. In particular, a robot that has the ability to recognize the environment and make its own decisions and take action can be called an intelligent robot.

[0213] Robots can be classified into industrial, medical, domestic, military, etc., depending on the purpose and field of use. Robots can perform various physical actions such as moving robot joints by having a driving part with an actuator or a motor. In addition, a mobile robot can run on the ground or fly in the air by using a driving part that includes wheels, brakes, propellers, etc.

[0214] Furthermore, the above-described technical features can be applied to a device that supports augmented reality.

[0215] Augmented reality is a collective term for virtual reality (VR), augmented reality (AR), and mixed reality (MR). VR technology provides real-world objects and backgrounds only as CG images, AR technology provides virtual CG images on real-world images, and MR technology is a computer graphics technology that combines and presents virtual objects in the real world.

[0216] MR technology is similar to AR technology in that it displays both real and virtual objects, but it differs in that AR technology uses virtual objects to complement real objects, whereas MR technology uses virtual objects and real objects with equal characteristics.

[0217] XR technology can be applied to HMDs (Head-Mount Displays), HUDs (Head-Up Displays), mobile phones, tablet PCs, laptops, desktops, TVs, digital signage, etc., and a device to which XR technology is applied can be called an XR device.

Claims

1. In a method executed in a WLAN (Wireless Local Area Network) system, a non-AP (non-access point) STA (station) transmits a sensing request frame to an AP (access point), wherein the sensing request frame enables calling a procedure for the non-AP STA to execute a sensing procedure on the AP, the sensing request frame includes information related to at least one sensing responder, and the non-AP STA receives a sensing response frame from the AP as a response to the sensing request frame, the non-AP STA receives a sensing report frame from the AP, and the sensing report frame includes a sensing measurement report received by the AP. A method.

2. The sensing request frame includes sensing role information having a length of 1 bit, wherein the sensing role information is related to whether the non-AP STA operates as a sensing transmitter role or a sensing receiver role. The method according to claim 1.

3. The sensing role information has a value of 1 based on the non-AP STA operating as the sensing receiver role. The method according to claim 2.

4. In a non-AP (non-access point) STA (station) in a WLAN (Wireless Local Area Network) system, a memory, and a processor operably coupled to the memory, wherein the processor transmits a sensing request frame to an AP (access point), the sensing request frame enables calling a procedure for the non-AP STA to execute a sensing procedure on the AP, the sensing request frame includes information related to at least one sensing responder, and receives a sensing response frame from the AP as a response to the sensing request frame, A non-AP STA adapted to receive a sensing report frame from the AP, the sensing report frame including a sensing measurement report received by the AP. **Claim 5** In a method executed in a WLAN (Wireless Local Area Network) system, a step in which an AP (access point) receives a sensing request frame from a non-AP STA (station), the sensing request frame enabling the non-AP STA to call a procedure for requesting the AP to execute a sensing procedure, the sensing request frame including information related to at least one sensing responder, a step in which the AP transmits a sensing response frame to the non-AP STA as a response to the sensing request frame, a step in which the AP transmits a sensing report frame to the non-AP STA, the sensing report frame including a sensing measurement report received by the AP, the method comprising the steps. **Claim 6** In an AP (access point) in a WLAN (Wireless Local Area Network) system, a memory, a processor operably coupled to the memory, the processor receives a sensing request frame from a non-AP STA (station), the sensing request frame enabling the non-AP STA to call a procedure for requesting the AP to execute a sensing procedure, the sensing request frame including information related to at least one sensing responder, transmits a sensing response frame to the non-AP STA as a response to the sensing request frame, an AP adapted to transmit a sensing report frame to the non-AP STA, the sensing report frame including a sensing measurement report received by the AP.

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