Method and apparatus for performing sensing measurements in a wireless LAN system

Abstract

A method and apparatus operating in a wireless LAN system are disclosed. According to an embodiment of the present disclosure, a method performed by a first station in the wireless LAN system includes: receiving a first sensing trigger frame from a second station, the first sensing trigger frame including a sensing trigger subtype field; and transmitting a first feedback frame associated with a first NDP received from the second station to the second station based on the first sensing trigger frame. If the sensing trigger subtype field indicates a sensing threshold-based report, the first feedback frame may include a CSI variation value, and if the sensing trigger subtype field indicates a sensing report, the first feedback frame may include CSI based on the first NDP.

Description

[Technical Field]

[0001] The present disclosure relates to communication operations in a Wireless Local Area Network (WLAN) system, and more particularly to a method and apparatus for performing sensing measurements in a WLAN system. [Background technology]

[0002] New technologies have been introduced to wireless LANs (WLANs) to improve transmission rates, increase bandwidth, improve reliability, reduce errors, and reduce latency. Among WLAN technologies, the IEEE (Institute of Electrical and Electronics Engineers) 802.11 series of standards can be referred to as Wi-Fi. For example, technologies recently introduced to WLANs include enhancements for Very High-Throughput (VHT) in the 802.11ac standard and enhancements for High Efficiency (HE) in the IEEE 802.11ax standard.

[0003] Improved technologies for providing sensing for devices using WLAN signals (i.e., WLAN sensing) are being discussed. For example, the IEEE 802.11 Task Group (TG) bf is currently developing standard technologies for sensing objects (e.g., people, objects, etc.) based on channel estimation using WLAN signals between devices operating in the sub-7 GHz and 60 Hz frequency bands. Object sensing based on WLAN signals has the advantages of being able to utilize existing frequency bands and being less likely to invade privacy compared to existing sensing technologies. The expanded frequency range available in WLAN technology makes it possible to obtain precise sensing information. At the same time, technologies for reducing power consumption to efficiently support precise sensing procedures are also being researched. Summary of the Invention [Problem to be solved by the invention]

[0004] The technical problem of the present disclosure is to provide a method and apparatus for performing sensing measurements in a wireless LAN system.

[0005] The technical problem of the present disclosure is to provide a method and apparatus for threshold-based sensing measurement reporting in a wireless LAN system.

[0006] A technical problem of the present disclosure is to provide a method and apparatus for transmitting and receiving a threshold-based report trigger frame to request a report on a sensing measurement result.

[0007] The technical problems to be solved by the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the following description. [Means for solving the problem]

[0008] According to one embodiment of the present disclosure, a method performed by a first station (STA) in a wireless LAN system includes: receiving a first sensing trigger frame from a second STA, the first sensing trigger frame including a sensing trigger subtype field; and transmitting a first feedback frame associated with a first NDP (null data physical protocol data unit (PPDU)) received from the second STA based on the first sensing trigger frame to the second STA, wherein the first feedback frame may include a channel state information (CSI) variation value based on sensing threshold-based reporting being indicated by the sensing trigger subtype field, and the first feedback frame may include CSI based on the first NDP based on sensing reporting being indicated by the sensing trigger subtype field.

[0009] As yet another example of the present disclosure, a method performed by a second station (STA) in a wireless LAN system includes the steps of: transmitting a first sensing trigger frame including a sensing trigger subtype field to at least one STA; and receiving a first feedback frame associated with a first NDP (null data physical protocol data unit (PPDU)) transmitted by the second STA based on the first sensing trigger frame from the at least one STA, wherein the first feedback frame may include a channel state information (CSI) variation value based on sensing threshold-based reporting being indicated by the sensing trigger subtype field, and the first feedback frame may include CSI based on the first NDP based on sensing reporting being indicated by the sensing trigger subtype field. [Effects of the Invention]

[0010] Various embodiments of the present disclosure may provide a method and apparatus for performing sensing measurements in a wireless LAN system.

[0011] Various embodiments of the present disclosure may provide a method and apparatus for threshold-based sensing measurement reporting in a wireless LAN system.

[0012] Various embodiments of the present disclosure may provide a method and apparatus for transmitting and receiving a threshold-based report trigger frame to request a report on a sensing measurement result.

[0013] Various embodiments of the present disclosure allow other types of reports to be efficiently requested by trigger frames without defining new procedures.

[0014] The effects obtained from the present disclosure are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those having ordinary skill in the art to which the present disclosure pertains from the following description. [Brief explanation of the drawings]

[0015] The accompanying drawings, which are included as part of the detailed description to aid in understanding the present disclosure, provide examples for the present disclosure and, together with the detailed description, explain the technical features of the present disclosure.

[0016] [Figure 1] FIG. 1 is a block diagram illustrating a wireless communication device according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a diagram illustrating an exemplary structure of a wireless LAN system to which the present disclosure can be applied. [Figure 3] FIG. 1 is a diagram illustrating a link setup process to which the present disclosure can be applied. [Figure 4] FIG. 10 is a diagram illustrating a backoff process to which the present disclosure can be applied. [Figure 5] 10A and 10B are diagrams for explaining a CSMA / CA base frame transmission operation to which the present disclosure can be applied. [Figure 6] 1 is a diagram illustrating an example of a frame structure used in a wireless LAN system to which the present disclosure can be applied. [Figure 7] FIG. 1 illustrates an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure is applicable. [Figure 8] FIG. 10 illustrates an exemplary format of a trigger frame to which the present disclosure can be applied. [Figure 9] 10 is a diagram for explaining an operation performed by a first STA according to an embodiment of the present disclosure. [Figure 10] FIG. 10 is a diagram for explaining an operation performed by a second STA according to an embodiment of the present disclosure. [Figure 11] FIG. 10 is a diagram illustrating a threshold-based reporting procedure according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0017] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. The detailed description disclosed below together with the accompanying drawings is intended to describe exemplary embodiments of the present disclosure and is not intended to represent the only embodiments in which the present disclosure can be implemented. The detailed description below includes specific details to provide a complete understanding of the present disclosure. However, it will be understood by those skilled in the art that the present disclosure can be implemented without such specific details.

[0018] In some cases, in order to avoid obscuring the concepts of the present disclosure, known structures and devices may be omitted or shown in block diagram form, focusing on the core functions of each structure and device.

[0019] In this disclosure, when a component is "coupled," "coupled," or "connected" to another component, this may include a direct connection as well as an indirect connection where there is another component between them. Also, in this disclosure, the terms "comprise" or "have" specify the presence of stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0020] In this disclosure, terms such as "first" and "second" are used only to distinguish one component from another, and are not used to limit the components, and do not limit the order or importance of the components unless otherwise specified. Therefore, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

[0021] The terms used in this disclosure are for the purpose of describing particular embodiments and are not intended to limit the scope of the claims. As used in the description of the embodiments and the appended claims, the singular is intended to include the plural unless the context clearly dictates otherwise. The term "and / or" as used in this disclosure means that one of the associated listed items may be included, or that any and all possible combinations of two or more of them are included. Also, in this disclosure, " / " between words has the same meaning as "and / or" unless otherwise specified.

[0022] The examples of the present disclosure may be applied to various wireless communication systems. For example, the examples of the present disclosure may be applied to a wireless LAN system. For example, the examples of the present disclosure may be applied to a wireless LAN based on the IEEE 802.11a / g / n / ac / ax standard. Note that the examples of the present disclosure may be applied to a wireless LAN based on the newly proposed IEEE 802.11bn (or UHR) standard. Furthermore, the examples of the present disclosure may be applied to a next-generation standard-based wireless LAN after IEEE 802.11bn. Furthermore, the examples of the present disclosure may be applied to a cellular wireless communication system. For example, the examples of the present disclosure may be applied to a cellular wireless communication system based on the Long Term Evolution (LTE) series of technologies and the 5G New Radio (NR) series of technologies of the 3GPP (registered trademark) standard.

[0023] Below, technical features to which the examples of the present disclosure can be applied will be described.

[0024] FIG. 1 is a block diagram illustrating a wireless communication device according to an embodiment of the present disclosure.

[0025] 1 may be referred to by various terms such as a terminal, a wireless device, a wireless transmit receive unit (WTRU), a user equipment (UE), a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a mobile subscriber unit (MSS), a subscriber station (SS), an advanced mobile station (AMS), a wireless terminal (WT), or simply a user. In addition, the first device 100 and the second device 200 may be referred to by various terms such as an access point (AP), a base station (BS), a fixed station, a Node B, a base transceiver system (BTS), a network, an artificial intelligence (AI) system, a road side unit (RSU), a repeater, a router, a relay, a gateway, etc.

[0026] The devices 100 and 200 illustrated in FIG. 1 may also be referred to as stations (STAs). For example, the devices 100 and 200 illustrated in FIG. 1 may be referred to by various terms, such as a transmitting device, a receiving device, a transmitting STA, or a receiving STA. For example, the STAs 110 and 200 may serve as an access point (AP) or a non-AP. That is, in the present disclosure, the STAs 110 and 200 may have AP and / or non-AP functionality. When the STAs 110 and 200 have AP functionality, they may simply be referred to as APs, and when the STAs 110 and 200 have non-AP functionality, they may simply be referred to as STAs. Also, in the present disclosure, an AP may be referred to as an AP STA.

[0027] 1, a first device 100 and a second device 200 may transmit and receive wireless signals using various wireless LAN technologies (e.g., the IEEE 802.11 family). The first device 100 and the second device 200 may include interfaces for a medium access control (MAC) layer and a physical layer (PHY) in accordance with the IEEE 802.11 standard.

[0028] In addition, the first device 100 and the second device 200 may further support various communication standards (e.g., 3GPP LTE series, 5G NR series standards, etc.) other than WLAN technology. Furthermore, the devices of the present disclosure may be embodied as various devices such as mobile phones, vehicles, personal computers, augmented reality (AR) equipment, and virtual reality (VR) equipment. Furthermore, the STAs of the present disclosure may support various communication services such as voice calls, video calls, data communications, autonomous driving, machine-type communication (MTC), machine-to-machine (M2M), device-to-device (D2D), and Internet-of-Things (IoT).

[0029] The first device 100 includes one or more processors 102 and one or more memories 104, and may additionally include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may be configured to control the memory 104 and / or the transceiver 106 to implement the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts of the present disclosure. For example, the processor 102 may process information in the memory 104 to generate first information / signals, and then transmit a wireless signal including the first information / signals via the transceiver 106. The processor 102 may also receive a wireless signal including second information / signals via the transceiver 106, and then store information obtained from signal processing of the second information / signals in the memory 104. The memory 104 may be coupled to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may store software code including instructions for executing some or all of the processes controlled by the processor 102 or for implementing the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts in this disclosure. Here, the processor 102 and the memory 104 may be part of a communications modem / circuit / chip designed to implement wireless LAN technology (e.g., the IEEE 802.11 series). The transceiver 106 may be coupled to the processor 102 and may transmit and / or receive wireless signals via one or more antennas 108. The transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be used interchangeably with an RF (Radio Frequency) unit. In this disclosure, a device may also refer to a communications modem / circuit / chip.

[0030] The second device 200 includes one or more processors 202, one or more memories 204, and may additionally include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may be configured to control the memory 204 and / or the transceiver 206 to implement the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in this disclosure. For example, the processor 202 may process information in the memory 204 to generate third information / signal, and then transmit a wireless signal including the third information / signal via the transceiver 206. The processor 202 may also receive a wireless signal including fourth information / signal via the transceiver 206, and then store information obtained from signal processing of the fourth information / signal in the memory 204. The memory 204 may be coupled to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may store software code including instructions for executing some or all of the processes controlled by the processor 202 or for implementing the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in this disclosure. Here, the processor 202 and the memory 204 may be part of a communications modem / circuit / chip designed to implement wireless LAN technology (e.g., the IEEE 802.11 series). The transceiver 206 may be coupled to the processor 202 and may transmit and / or receive wireless signals via one or more antennas 208. The transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be used interchangeably with an RF unit. In this disclosure, a device may also refer to a communications modem / circuit / chip.

[0031] The hardware elements of the devices 100, 200 are described in more detail below. Without limitation, one or more protocol layers may be implemented by one or more processors 102, 202. For example, one or more processors 102, 202 may implement one or more layers (e.g., functional layers such as PHY and MAC). The one or more processors 102, 202 may generate one or more protocol data units (PDUs) and / or one or more service data units (SDUs) according to the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams in this disclosure. The one or more processors 102, 202 may generate messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams in this disclosure. The one or more processors 102, 202 can generate and provide signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, suggestions, and / or methods of this disclosure to the one or more transceivers 106, 206. The one or more processors 102, 202 can receive signals (e.g., baseband signals) from the one or more transceivers 106, 206 and obtain the PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts of this disclosure.

[0032] The one or more processors 102, 202 may be referred to as a controller, microcontroller, microprocessor, or microcomputer. The one or more processors 102, 202 may be implemented using hardware, firmware, software, or a combination thereof. As an example, the one or more processors 102, 202 may include one or more application-specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs). The descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in this disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. Firmware or software configured to execute the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in this disclosure may be included in one or more processors 102, 202 or stored in one or more memories 104, 204 and executed by one or more processors 102, 202. The descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in this disclosure may be embodied by firmware or software in the form of code, instructions, and / or collections of instructions.

[0033] One or more memories 104, 204 may be coupled to one or more processors 102, 202 and may store various types of data, signals, messages, information, programs, code, instructions, and / or instructions. The one or more memories 104, 204 may be comprised of ROM, RAM, EPROM, flash memory, hard drives, registers, cache memory, computer-readable storage media, and / or combinations thereof. The one or more memories 104, 204 may be located internal and / or external to the one or more processors 102, 202. Additionally, the one or more memories 104, 204 may be coupled to the one or more processors 102, 202 via various techniques, such as wired or wireless connections.

[0034] One or more transceivers 106, 206 may transmit user data, control information, wireless signals / channels, etc., as referred to in the methods and / or operational flowcharts of the present disclosure, to one or more other devices. One or more transceivers 106, 206 may receive user data, control information, wireless signals / channels, etc., as referred to in the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts of the present disclosure, from one or more other devices. For example, one or more transceivers 106, 206 may be coupled to one or more processors 102, 202 and may transmit and receive wireless signals. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other devices. Also, one or more processors 102, 202 may control one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. Furthermore, one or more transceivers 106, 206 may be coupled to one or more antennas 108, 208, and the one or more transceivers 106, 206 may be configured to transmit and receive user data, control information, wireless signals / channels, etc., referred to in the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in this disclosure, via the one or more antennas 108, 208. In this disclosure, the one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). The one or more transceivers 106, 206 may convert the received user data, control information, wireless signals / channels, etc., from RF band signals to baseband signals for processing using one or more processors 102, 202. The one or more transceivers 106, 206 may convert the user data, control information, wireless signals / channels, etc., processed using one or more processors 102, 202, from baseband signals to RF band signals. To that end, one or more of the transceivers 106, 206 may include (analog) oscillators and / or filters.

[0035] For example, one of the STAs 100 and 200 may perform operations intended for an AP, and the other of the STAs 100 and 200 may perform operations intended for a non-AP STA. For example, the transceivers 106 and 206 in FIG. 1 may perform operations for transmitting and receiving signals (e.g., packets or PPDUs (Physical Layer Protocol Data Units) conforming to IEEE 802.11a / b / g / n / ac / ax / be / bn, etc.). In addition, in the present disclosure, operations for various STAs to generate transmission / reception signals or to perform data processing or calculations in advance for transmission / reception signals may be performed by the processors 102 and 202 in FIG. 1. For example, examples of operations for generating transmission / reception signals or performing data processing or calculations in advance for transmission / reception signals may include: 1) operations for determining / obtaining / configuring / calculating / decoding / encoding bit information of fields included in a PPDU (SIG (signal), STF (short training field), LTF (long training field), Data, etc.); 2) operations for determining / configuring / obtaining time resources and frequency resources (e.g., subcarrier resources) to be used for fields included in a PPDU (SIG, STF, LTF, Data, etc.); 3) operations for determining / configuring / obtaining specific sequences (e.g., pilot sequences, STF / LTF sequences, extra sequences applied to SIG) to be used for fields included in a PPDU (SIG, STF, LTF, Data, etc.); 4) power control operations and / or power saving operations applied to STAs; and 5) operations related to determining / obtaining / configuring / calculating / decoding / encoding ACK signals, etc. In addition, in the example below, various information (e.g., information regarding fields / subfields / control fields / parameters / power, etc.) used by various STAs to determine / acquire / configure / calculate / decode / encode transmitted / receive signals may be stored in memories 104, 204 of FIG. 1.

[0036] Hereinafter, downlink (DL) refers to a link for communication from an AP STA to a non-AP STA, and downlink PPDUs / packets / signals, etc. may be transmitted and received via the downlink. In downlink communication, the transmitter may be part of the AP STA, and the receiver may be part of the non-AP STA. Uplink (UL) refers to a link for communication from a non-AP STA to an AP STA, and uplink PPDUs / packets / signals, etc. may be transmitted and received via the uplink. In uplink communication, the transmitter may be part of the non-AP STA, and the receiver may be part of the AP STA.

[0037] FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0038] The structure of a WLAN system may be composed of multiple components. The interaction of these components may provide a WLAN that supports STA mobility transparent to higher layers. A Basic Service Set (BSS) is a basic building block of a WLAN. FIG. 2 illustrates two BSSs (BSS1 and BSS2), each including two STAs as members (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). The ellipses representing BSSs in FIG. 2 may be understood to represent coverage areas where STAs included in the BSSs maintain communication. This area may be referred to as a Basic Service Area (BSA). If a STA moves outside a BSA, it will no longer be able to directly communicate with other STAs within the BSA.

[0039] Ignoring the DS shown in FIG. 2, the most basic type of BSS in a WLAN is the Independent BSS (IBSS). For example, an IBSS may have a minimal configuration consisting of only two STAs. For example, assuming that other components are omitted, BSS1 consisting of only STA1 and STA2, or BSS2 consisting of only STA3 and STA4, are representative examples of an IBSS. Such a configuration is possible when STAs can communicate directly without an AP. Furthermore, in such a WLAN, a BSS may be configured when needed by the LAN, rather than being configured in advance. This can also be called an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. That is, in an IBSS, STAs are managed in a distributed manner. In an IBSS, all STAs may be mobile, and connection to a distributed system (DS) is not permitted, forming a self-contained network.

[0040] The membership of STAs in a BSS may change dynamically as STAs join and leave the BSS area, etc. To become a member of a BSS, a STA may join the BSS using a synchronization process. To access all the services of the BSS-based architecture, a STA must be associated with the BSS. Such association may be dynamically configured and may include the use of a Distribution System Service (DSS).

[0041] In a wireless LAN, direct STA-to-STA distance may be limited by PHY performance. While such distance limits are sufficient in some cases, other situations may require communication between STAs over longer distances. A distributed system (DS) may be configured to support extended coverage.

[0042] A DS refers to a structure in which BSSs are interconnected. Specifically, as shown in FIG. 2, a BSS may exist as a component of an expanded network composed of multiple BSSs. A DS is a logical concept and may be specified by the characteristics of a distributed system medium (DSM). In this regard, a wireless medium (WM) and a DSM may be logically distinguished. Each logical medium is used for different purposes and by different components. These media are neither limited to being the same nor limited to being different. The flexibility of a WLAN structure (DS structure or other network structure) can be explained by the fact that multiple media are logically distinct from one another. That is, a WLAN structure may be embodied in various ways, and the WLAN structure may be independently specified according to the physical characteristics of each implementation.

[0043] The DS can support mobile devices by providing seamless integration of multiple BSSs and logical services necessary for addressing destinations. The DS may also include a portal component that acts as a bridge between the wireless LAN and other networks (e.g., IEEE 802.X).

[0044] An AP is an entity that allows associated non-AP STAs to access the DS through the WM and also has the functionality of an STA. Data can be transferred between a BSS and a DS via the AP. For example, STA2 and STA3 shown in FIG. 2 have the functionality of an STA and provide the function of allowing associated non-AP STAs (STA1 and STA4) to access the DS. Furthermore, since all APs essentially correspond to STAs, all APs are addressable entities. The address used by an AP for communication on the WM does not necessarily have to be the same as the address used by the AP for communication on the DSM. A BSS consisting of an AP and one or more STAs can be called an infrastructure BSS.

[0045] Data transmitted from one of the STAs associated with an AP to the STA address of that AP is always received on the uncontrolled port and may be processed by the IEEE 802.1X port access entity, and once the controlled port is authenticated, the transmitted data (or frame) may be delivered to the DS.

[0046] In the above-described DS structure, an Extended Service Set (ESS) may be configured to provide wider coverage.

[0047] An ESS is a network of arbitrary size and complexity composed of a DS and a BSS. An ESS can be a collection of BSSs connected to one DS. However, an ESS does not include a DS. An ESS network is characterized by appearing as an IBSS at the Logical Link Control (LLC) layer. STAs included in an ESS can communicate with each other, and mobile STAs can move from one BSS to another (within the same ESS) transparently to the LLC. APs included in one ESS may have the same service set identification (SSID). An SSID is distinct from a BSSID, which is an identifier for a BSS.

[0048] A WLAN system does not make any assumptions about the relative physical locations of BSSs and can have any of the following configurations: BSSs may partially overlap, which is a configuration commonly used to provide continuous coverage; BSSs may not be physically connected, and there is no logical limit to the distance between BSSs; BSSs may be physically located in the same location, which may be used to provide redundancy; and one (or more) IBSS or ESS networks may physically exist in the same space as one (or more) ESS networks. This may apply to ESS network configurations when an ad-hoc network operates in the location where the ESS network exists, when physically overlapping wireless networks are formed by different organizations, or when two or more different access and security policies are required in the same location.

[0049] FIG. 3 is a diagram illustrating a link setup process to which the present disclosure can be applied.

[0050] In order for an STA to set up a link to a network and transmit and receive data, it must first discover the network, perform authentication, establish an association, and perform authentication procedures for security. The link setup process can also be called a session initiation process or a session setup process. In addition, the discovery, authentication, association, and security configuration processes of the link setup process can also be collectively called the association process.

[0051] In step S310, the STA may perform a network discovery operation. The network discovery operation may include a scanning operation of the STA. That is, in order for the STA to access a network, the STA must search for a joinable network. Before joining a wireless network, the STA must identify a compatible network. The process of identifying networks present in a specific area is called scanning.

[0052] Scanning methods include active scanning and passive scanning. FIG. 3 illustrates an example of a network discovery operation including an active scanning process. In active scanning, a scanning STA changes channels and transmits a probe request frame to search for nearby APs, and waits for a response. A responder transmits a probe response frame to the STA that transmitted the probe request frame in response to the probe request frame. Here, the responder may be the STA that last transmitted a beacon frame in the BSS of the channel being scanned. In a BSS, the AP transmits beacon frames, so the AP is the responder. In an IBSS, the STAs in the IBSS transmit beacon frames alternately, so the responder is not constant. For example, an STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 can store the BSS-related information contained in the received probe response frame, move to the next channel (e.g., channel 2), and perform scanning in the same manner (i.e., send and receive probe requests / responses on channel 2).

[0053] Although not shown in FIG. 3, the scanning operation may be performed in a passive scanning manner. In passive scanning, a scanning STA waits for a beacon frame while changing channels. A beacon frame is a management frame defined in IEEE 802.11 and is periodically transmitted to announce the existence of a wireless network and allow a scanning STA to search for and join the wireless network. In a BSS, the AP is responsible for periodically transmitting beacon frames, while in an IBSS, STAs within the IBSS transmit beacon frames in turn. When a scanning STA receives a beacon frame, it saves the BSS-related information included in the beacon frame and records the beacon frame information on each channel as it moves to other channels. A STA that receives a beacon frame saves the BSS-related information included in the received beacon frame, moves to the next channel, and scans the next channel in the same manner. Comparing active scanning with passive scanning, active scanning has the advantage of having a smaller delay and power consumption than passive scanning.

[0054] After the STA discovers the network, an authentication process may be performed in step S320. This authentication process may be called a first authentication process to clearly distinguish it from the security setup operation in step S340, which will be described later.

[0055] The authentication process involves a STA sending an authentication request frame to an AP, and the AP responding by sending an authentication response frame to the STA. The authentication frame used for the authentication request / response corresponds to a management frame.

[0056] The authentication frame may include information such as an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a Robust Security Network (RSN), a Finite Cyclic Group, etc. These are only examples of information that may be included in an authentication request / response frame, and other information may be substituted or additional information may be included.

[0057] The STA can send an authentication request frame to the AP. The AP can determine whether to allow authentication for the STA based on the information contained in the received authentication request frame. The AP can provide the STA with the result of the authentication process using an authentication response frame.

[0058] After the STA is successfully authenticated, an association process may be performed in step S330. The association process includes the STA sending an association request frame to the AP, and the AP responding by sending an association response frame to the STA.

[0059] For example, the association request frame may include information on various capabilities, a beacon listen interval, a service set identifier (SSID), supported rates, supported channels, an RSN, a mobility domain, supported operating classes, a Traffic Indication Map Broadcast request, interworking service capabilities, etc. For example, the association response frame may include information on various capabilities, a status code, an association ID (AID), supported rates, an Enhanced Distributed Channel Access (EDCA) parameter set, a Received Channel Power Indicator (RCPI), a Received Signal to Noise Indicator (RSNI), a mobility domain, a timeout interval (e.g., an association comeback time), overlapping BSS scan parameters, a TIM broadcast response, a Quality of Service (QoS) map, etc. This corresponds to only a partial example of information that may be included in the association request / response frame, and other information may be substituted or additional information may be included.

[0060] After the STA is successfully connected to the network, a security setup process may be performed in step S340. The security setup process in step S340 may also be referred to as an authentication process using a Robust Security Network Association (RSNA) request / response, and the authentication process in step S320 may be referred to as a first authentication process, and the security setup process in step S340 may simply be referred to as an authentication process.

[0061] The security setup process of step S340 may include a process of performing private key setup using, for example, four-way handshaking using an Extensible Authentication Protocol over LAN (EAPOL) frame, and may also be performed using a security method not defined in the IEEE 802.11 standard.

[0062] FIG. 4 is a diagram illustrating a backoff process to which the present disclosure can be applied.

[0063] In wireless LAN systems, the basic access mechanism of MAC (Medium Access Control) is the Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) mechanism, also known as the Distributed Coordination Function (DCF) of IEEE 802.11 MAC, which basically employs a "listen before talk" access mechanism. According to this type of access mechanism, the AP and / or STA can perform a Clear Channel Assessment (CCA) to sense the wireless channel or medium for a predetermined time period (e.g., a DCF Inter-Frame Space (DIFS)) before starting transmission. If the sensing result indicates that the medium is in an idle status, the AP and / or STA can start transmitting a frame over the medium. On the other hand, if the medium is detected as occupied or busy, the AP and / or STA can wait for a delay period (e.g., a random backoff period) for medium access without starting its own transmission, and then attempt to transmit a frame. By applying the random backoff period, multiple STAs are expected to wait for different periods of time before attempting to transmit a frame, thereby minimizing collisions.

[0064] The IEEE 802.11 MAC protocol also provides a Hybrid Coordination Function (HCF). HCF is based on the DCF and Point Coordination Function (PCF). PCF is a polling-based synchronous access method that periodically polls all receiving APs and / or STAs to receive data frames. HCF also includes Enhanced Distributed Channel Access (EDCA) and HCF Controlled Channel Access (HCCA). EDCA is a contention-based access method for a provider to provide data frames to multiple users, while HCCA is a non-contention-based channel access method using a polling mechanism. HCF also includes a medium access mechanism for improving the quality of service (QoS) of wireless LANs, and can transmit QoS data in both a contention period (CP) and a contention-free period (CFP).

[0065] The operation based on the random backoff period will be described with reference to FIG. 4. When an occupied / busy medium changes to an idle state, multiple STAs can attempt to transmit data (or frames). As a method for minimizing collisions, each STA can select a random backoff count and attempt transmission after waiting for the corresponding slot time. The random backoff count has a pseudo-random integer value and may be determined to be one of the values ​​in the range of 0 to CW. Here, CW is the contention window parameter value. The CW parameter is given a CWmin as its initial value, but can be doubled in the event of a transmission failure (e.g., if an ACK for a transmitted frame is not received). When the CW parameter value reaches CWmax, data transmission can be attempted while maintaining the CWmax value until data transmission is successful, and if data transmission is successful, it is reset to the CWmin value. The CW, CWmin, and CWmax values ​​are set to 2. n Preferably it is set to -1 (n=0,1,2,...).

[0066] When the random backoff process begins, the STA continuously monitors the medium while counting down the backoff slots according to the determined backoff count value. If the medium is monitored as occupied, the STA stops counting down and waits. If the medium becomes idle, the STA resumes the remaining countdown.

[0067] In the example of FIG. 4, when a packet to be transmitted arrives at the MAC of STA3, STA3 confirms that the medium is idle for DIFS and can immediately transmit a frame. The remaining STAs monitor the medium for occupied / busy status and wait. Meanwhile, STA1, STA2, and STA5 may each have data to transmit. If each STA monitors the medium as idle, it waits for DIFS and then counts down its backoff slots according to its random backoff count value. Assume that STA2 selects the smallest backoff count value and STA1 selects the largest backoff count value. That is, this example illustrates a case where, at the time STA2 finishes its backoff count and begins frame transmission, STA5's remaining backoff time is shorter than STA1's remaining backoff time. STA1 and STA5 pause their countdowns and wait while STA2 occupies the medium. When STA2's occupation ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and then resume their backoff counts. That is, STA5 can start frame transmission after counting down the remaining backoff slots equal to the remaining backoff time. Because STA5's remaining backoff time is shorter than STA1's, STA5 begins frame transmission. While STA2 is occupying the medium, STA4 may also have data to transmit. From STA4's perspective, when the medium becomes idle, it waits for DIFS, then counts down the random backoff count value it selected, and can begin frame transmission. The example in FIG. 4 shows a case where STA5's remaining backoff time happens to match STA4's random backoff count value, which may result in a collision between STA4 and STA5. If a collision occurs, neither STA4 nor STA5 will receive an ACK, resulting in a failed data transmission. In this case, STA4 and STA5 can double their CW values, select a random backoff count value, and then count down.STA1 waits while the medium is occupied by transmissions from STA4 and STA5, but when the medium becomes idle, it waits for DIFS and can begin frame transmission once the remaining backoff time has elapsed.

[0068] As shown in the example of Figure 4, a data frame is a frame used for transmitting data to be forwarded to a higher layer, and may be transmitted after a backoff that occurs after a DIFS has elapsed since the medium became idle. Furthermore, a management frame is a frame used for exchanging management information that is not forwarded to a higher layer, and is transmitted after a backoff that occurs after an IFS, such as a DIFS or a PIFS (Point Coordination Function IFS). Subtype frames of management frames include a beacon, an association request / response, a re-association request / response, a probe request / response, and an authentication request / response. A control frame is a frame used to control access to a medium. Subtype frames of control frames include Request-To-Send (RTS), Clear-To-Send (CTS), Acknowledgment (ACK), Power Save-Poll (PS-Poll), BlockAck, BlockACKReq, NDP announcement (null data packet announcement), and Trigger. If a control frame is not a response frame of a previous frame, it is transmitted after a backoff that is performed after a DIFS has elapsed. If a control frame is a response frame of a previous frame, it is transmitted without a backoff after a short IFS (SIFS) has elapsed. The type and subtype of a frame may be identified by the type field and subtype field in the Frame Control (FC) field.

[0069] A Quality of Service (QoS) STA can transmit a frame after backing off after the arbitration IFS (AIFS) for the access category (AC) to which the frame belongs, i.e., AIFS[i] (where i is a value determined by the AC), has elapsed. Here, a frame that can use AIFS[i] can be a data frame, a management frame, or a control frame that is not a response frame.

[0070] FIG. 5 is a diagram for explaining a CSMA / CA base frame transmission operation to which the present disclosure can be applied.

[0071] As mentioned above, the CSMA / CA mechanism includes not only physical carrier sensing, in which a STA directly senses the medium, but also virtual carrier sensing. Virtual carrier sensing is intended to compensate for problems that may occur in medium access, such as the hidden node problem. For virtual carrier sensing, the MAC of a STA can use a network allocation vector (NAV). The NAV is a value that indicates to other STAs the time remaining until the medium becomes available for use by a STA currently using or authorized to use the medium. Therefore, the value set as the NAV corresponds to the period during which the STA transmitting the frame plans to use the medium, and STAs receiving the NAV value are prohibited from accessing the medium during that period. For example, the NAV may be set based on the value of the "duration" field in the MAC header of the frame.

[0072] In the example of FIG. 5, it is assumed that STA1 is attempting to transmit data to STA2, and STA3 is in a position where it can overhear some or all of the frames transmitted between STA1 and STA2.

[0073] In order to reduce the possibility of collisions between transmissions from multiple STAs in a CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames may be applied. In the example of FIG. 5, while STA1 is transmitting, STA3 may determine that the medium is idle as a result of carrier sensing. That is, STA1 may be a hidden node to STA3. Alternatively, in the example of FIG. 5, while STA2 is transmitting, STA3 may determine that the medium is idle as a result of carrier sensing. That is, STA2 may be a hidden node to STA3. By exchanging RTS / CTS frames before data transmission and reception between STA1 and STA2, STAs outside the transmission range of either STA1 or STA2, or outside the carrier sensing range for transmissions from STA1 or STA3, can be prevented from attempting to occupy the channel during data transmission and reception between STA1 and STA2.

[0074] Specifically, STA1 can determine whether a channel is occupied or not using carrier sensing. In terms of physical carrier sensing, STA1 can determine whether a channel is occupied or idle based on the energy magnitude or signal correlation detected from the channel. In terms of virtual carrier sensing, STA1 can determine whether a channel is occupied or idle using a network allocation vector (NAV) timer.

[0075] When the channel is idle in DIFS, STA1 can send an RTS frame to STA2 after backing off. When STA2 receives the RTS frame, it can send a CTS frame to STA1 as a response to the RTS frame after SIFS.

[0076] If STA3 cannot overhear the CTS frame from STA2 but can overhear the RTS frame from STA1, STA3 can use the duration information included in the RTS frame to set a NAV timer for the frame transmission period (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame) that will be transmitted subsequently. Alternatively, if STA3 cannot overhear the RTS frame from STA1 but can overhear the CTS frame from STA2, STA3 can use the duration information included in the CTS frame to set a NAV timer for the frame transmission period (e.g., SIFS + data frame + SIFS + ACK frame) that will be transmitted subsequently. That is, if STA3 can overhear one or more RTS or CTS frames from at least one of STA1 and STA2, it can set a NAV based thereon. If STA3 receives a new frame before the NAV timer expires, it can update the NAV timer using the duration information included in the new frame. STA3 does not attempt channel access until the NAV timer expires.

[0077] When STA1 receives a CTS frame from STA2, it can transmit a data frame to STA2 SIFS after the completion of reception of the CTS frame. When STA2 successfully receives a data frame, it can transmit an ACK frame, which is a response to the data frame, to STA1 SIFS after the completion of reception of the CTS frame. When STA3's NAV timer expires, it can use carrier sensing to determine whether the channel is in use. If STA3 determines that the channel is not in use by another terminal within DIFS after the expiration of the NAV timer, it can attempt channel access after the contention window (CW) with random backoff has elapsed.

[0078] FIG. 6 is a diagram illustrating an example of a frame structure used in a wireless LAN system to which the present disclosure can be applied.

[0079] The PHY layer can prepare an MPDU (MAC PDU) to be transmitted based on an instruction or primitive (meaning a set of instructions or parameters) from the MAC layer. For example, when the PHY layer receives a command from the MAC layer requesting the start of PHY layer transmission, the PHY layer switches to transmission mode and transmits information (e.g., data) provided by the MAC layer in the form of a frame. In addition, when the PHY layer detects a valid preamble in a received frame, it monitors the preamble header and sends a command to the MAC layer informing the start of PHY layer reception.

[0080] Thus, information transmission / reception in a wireless LAN system is performed in the form of frames, and for this purpose, a PHY layer protocol data unit (PPDU) frame format is defined.

[0081] A basic PPDU may include a Short Training Field (STF), a Long Training Field (LTF), a Signal (SIG) field, and a Data field. The most basic PPDU format (e.g., non-High Throughput (HT) shown in FIG. 7) may consist of only a Legacy-STF (L-STF), a Legacy-LTF (L-LTF), a Legacy-SIG (L-SIG) field, and a Data field. Depending on the type of PPDU format (e.g., HT-mixed format PPDU, HT-greenfield format PPDU, Very High Throughput (VHT) PPDU, etc.), an additional (or other type) RL-SIG, U-SIG, non-legacy SIG field, non-legacy STF, non-legacy LTF (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)), etc. may be included between the L-SIG field and the Data field. More specific details will be described later with reference to FIG.

[0082] The STF is a signal for signal detection, AGC (Automatic Gain Control), diversity selection, precise time synchronization, etc., and the LTF is a signal for channel estimation, frequency error estimation, etc. The STF and LTF can be said to be signals for synchronization and channel estimation of the OFDM physical layer.

[0083] The SIG field may contain various information related to PPDU transmission and reception. For example, the L-SIG field may be composed of 24 bits and may include a 4-bit Rate field, a 1-bit Reserved bit, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field. The RATE field may contain information regarding the modulation and coding rate of the data. For example, the 12-bit Length field may contain 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 PPDU. For example, for non-HT, HT, VHT, or EHT PPDU, the value of the Length field may be determined as a multiple of 3. For example, for HE PPDU, the value of the Length field may be determined as a multiple of 3 + 1 or a multiple of 3 + 2.

[0084] The data field may include a SERVICE field, a PSDU (Physical layer Service Data Unit), a PPDU TAIL bit, and, if necessary, padding bits. Some bits of the SERVICE field may be used for synchronization of a descrambler at the receiving end. The PSDU corresponds to a MAC PDU defined in the MAC layer and may contain data generated / used by a higher layer. The PPDU TAIL bit may be used to return the encoder to a 0 state. The padding bits may be used to adjust the length of the data field to a predetermined unit.

[0085] The MAC PDU is defined by various MAC frame formats, and a basic MAC frame consists of a MAC header, a frame body, and a Frame Check Sequence (FCS). The MAC frame is composed of the MAC PDU and may be transmitted / received by the PSDU in the data portion of the PPDU format.

[0086] The MAC header includes a Frame Control field, a Duration / ID field, an Address field, etc. The Frame Control field may include control information required for frame transmission / reception. The Duration / ID field may be set to the time for transmitting the frame, etc. The Address subfield may indicate the receiver address, transmitter address, destination address, or source address of the frame, and some of the Address subfields may be omitted. The MAC header includes Sequence Control, QoS Control, and HT Control subfields. For specific contents of each subfield of the MAC header, please refer to the IEEE 802.11 standard document.

[0087] The null data PPDU (NDP) format refers to a PPDU format that does not include a data field, i.e., NDP refers to a frame format that includes a PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields, and, if present, non-legacy SIG, non-legacy STF, and non-legacy LTF) in a general PPDU format, but does not include the remaining part (i.e., data field).

[0088] FIG. 7 is a diagram illustrating an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure is applicable.

[0089] Various types of PPDUs are used in standards such as IEEE 802.11a / g / n / ac / ax. The basic PPDU format (IEEE 802.11a / g) includes an L-LTF, an L-STF, an L-SIG, and a Data field. The basic PPDU format can also be called a non-HT PPDU format (see FIG. 7(a)).

[0090] The HT PPDU format (IEEE 802.11n) further includes HT-SIG, HT-STF, and HT-LFT(s) fields in addition to the basic PPDU format. The HT PPDU format shown in Figure 7(b) can be referred to as an HT-mixed format. An HT-greenfield format PPDU may also be defined, which corresponds to a format that does not include L-STF, L-LTF, or L-SIG, but is composed of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a Data field (not shown).

[0091] An example of a VHT PPDU format (IEEE 802.11ac) further includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in addition to the basic PPDU format (FIG. 7(c)).

[0092] An example of the HE PPDU format (IEEE 802.11ax) further includes the fields Repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), and Packet Extension (PE) in addition to the basic PPDU format (FIG. 7(d)). Depending on the detailed example of the HE PPDU format, some fields may be excluded or their lengths may vary. For example, the HE-SIG-B field is included in the HE PPDU format for multiple users (MU), but not in the HE PPDU format for single users (SU). Also, the HE trigger-based (TB) PPDU format does not include the HE-SIG-B, and the length of the HE-STF field may be 8 us. The HE Extended Range (ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may be 16 us. For example, the RL-SIG may be configured to be the same as the L-SIG. Based on the presence of the RL-SIG, the receiving STA can determine that the received PPDU is an HE PPDU or an EHT PPDU (described later).

[0093] The EHT PPDU format may include the EHT MU (multi-user) PPDU in Figure 7(e) and the EHT TB (trigger-based) PPDU in Figure 7(f). The EHT PPDU format is similar to the HE PPDU format in that it includes an RL-SIG following an L-SIG, but it may also include a U (universal)-SIG, EHT-SIG, EHT-STF, and EHT-LTF following the RL-SIG.

[0094] The EHT MU PPDU in Figure 7(e) corresponds to a PPDU that carries one or more data (or PSDUs) for one or more users. That is, the EHT MU PPDU may be used for both SU transmission and MU transmission. For example, the EHT MU PPDU may correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0095] The EHT TB PPDU in Figure 7(f) omits the EHT-SIG compared to the EHT MU PPDU. A STA that receives a trigger for UL MU transmission (e.g., a trigger frame or TRS (triggered response scheduling)) can perform UL transmission based on the EHT TB PPDU format.

[0096] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal Signal), and EHT-SIG fields may be encoded and modulated and mapped based on a specified subcarrier frequency interval (e.g., 312.5 kHz) so that legacy STAs can also attempt demodulation and decoding. These may be referred to as pre-EHT modulated fields. Next, the EHT-STF, EHT-LTF, Data, and PE fields may be encoded and modulated and mapped based on a specified subcarrier frequency interval (e.g., 78.125 kHz) so that they can be demodulated and decoded by STAs that successfully decode non-legacy SIGs (e.g., U-SIG and / or EHT-SIG) and obtain the information contained in these fields. These may be referred to as EHT modulated fields.

[0097] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields can be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, Data, and PE fields can be referred to as HE modulation fields. Also, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be referred to as pre-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields can be referred to as VHT modulation fields.

[0098] The U-SIG included in the EHT PPDU format of Fig. 7 may be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG may have a duration of 4 us, and the entire U-SIG may have a duration of 8 us. Each symbol of the U-SIG may be used to transmit 26 bits of information. For example, each symbol of the U-SIG may be transmitted and received based on 52 data tones and 4 pilot tones.

[0099] U-SIGs may be configured in 20 MHz units. For example, when an 80 MHz PPDU is configured, the same U-SIG may be duplicated in 20 MHz units. That is, four identical U-SIGs may be included in an 80 MHz PPDU. When the bandwidth exceeds 80 MHz, for example, for a 160 MHz PPDU, the first U-SIG in the 80 MHz unit and the second U-SIG in the 80 MHz unit may be different from each other.

[0100] For example, a U-SIG may transmit A uncoded bits, with the first symbol of the U-SIG (e.g., U-SIG-1 symbol) transmitting the first X bits of the total A bits of information, and the second symbol of the U-SIG (e.g., U-SIG-2 symbol) transmitting the remaining Y bits of information. The A bits of information (e.g., 52 uncoded bits) may include a CRC field (e.g., a 4-bit field) and a tail field (e.g., a 6-bit field). The tail field may be used to terminate the trellis of a convolutional decoder and may be set to 0, for example.

[0101] The A-bit information transmitted by the U-SIG can be divided into version-independent bits and version-dependent bits. For example, the U-SIG may be included in a new PPDU format (e.g., a UHR PPDU format) not shown in Fig. 7. In the format of the U-SIG field included in the EHT PPDU format and the format of the U-SIG field included in the UHR PPDU format, the version-independent bits may be the same, but some or all of the version-dependent bits may be different.

[0102] For example, the size of the version-independent bits in a U-SIG may be fixed or variable. The version-independent bits may be assigned only to the U-SIG-1 symbol or to both the U-SIG-1 and U-SIG-2 symbols. The version-independent bits and version-dependent bits may be referred to by various names, such as first control bits and second control bits.

[0103] For example, the version independent bits of the U-SIG may include a 3-bit PHY version identifier, which may indicate the PHY version (e.g., EHT, UHR, etc.) of the transmitted and received PPDU. The version independent bits of the U-SIG may include a 1-bit UL / DL flag field. A first value of the 1-bit UL / DL flag field is associated with UL communication, and a second value of the UL / DL flag field is associated with DL communication. The version independent bits of the U-SIG may include information regarding the length of a transmission opportunity (TXOP) and information regarding a BSS color ID.

[0104] For example, the version dependent bits of the U-SIG may include information that directly or indirectly indicates the type of PPDU (eg, SU PPDU, MU PPDU, TB PPDU, etc.).

[0105] Information necessary for transmitting and receiving a PPDU may be included in the U-SIG. For example, the U-SIG may further include information about the bandwidth, information about an MCS scheme to be applied to a non-legacy SIG (e.g., an EHT-SIG or a UHR-SIG), information indicating whether a dual carrier modulation (DCM) scheme (e.g., a scheme for achieving an effect similar to frequency diversity by reusing the same signal on two subcarriers) is applied to the non-legacy SIG, information about the number of symbols used for the non-legacy SIG, information about whether the non-legacy SIG is generated across the entire band, etc.

[0106] Some of the information necessary for transmitting and receiving a PPDU may be included in the U-SIG and / or non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.). For example, information on the type of non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information on the length of the non-legacy LTF and the cyclic prefix (CP) length, information on the guard interval (GI) applied to the non-legacy LTF, information on preamble puncturing applicable to the PPDU, information on resource unit (RU) allocation, etc. may be included only in the U-SIG, or only in the non-legacy SIG, or may be indicated by a combination of information included in the U-SIG and information included in the non-legacy SIG.

[0107] Preamble puncturing may refer to the transmission of a PPDU in which no signal is present in one or more frequency units in the bandwidth of the PPDU. For example, the size of the frequency unit (or the resolution of the preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to PPDU bandwidths equal to or larger than a predetermined size.

[0108] 7, non-legacy SIGs such as HE-SIG-B and EHT-SIG may contain control information for receiving STAs. Non-legacy SIGs may be transmitted in at least one symbol, and one symbol may have a length of 4 us. Information regarding the number of symbols used for the EHT-SIG may be included in previous SIGs (e.g., HE-SIG-A, U-SIG, etc.).

[0109] Non-legacy SIGs such as HE-SIG-B and EHT-SIG may include common fields and user-specific fields, which may be coded separately.

[0110] In some cases, the common field may be omitted. For example, in a compressed mode where non-OFDMA (orthogonal frequency multiple access) is applied, the common field may be omitted and multiple STAs can receive the PPDU (e.g., the data field of the PPDU) in the same frequency band. In an uncompressed mode where OFDMA is applied, multiple users can receive the PPDU (e.g., the data field of the PPDU) in separate frequency bands.

[0111] The number of user-specific fields may be determined based on the number of users. One user block field may include up to two user fields. Each user field may be associated with a MU-MIMO allocation or a non-MU-MIMO allocation.

[0112] The common field may include CRC bits and tail bits, where the length of the CRC bits may be determined to be 4 bits, and the length of the tail bits may be determined to be 6 bits and set to 000000. The common field may include RU allocation information. The RU allocation information may include information regarding the locations of RUs to which multiple users (i.e., multiple receiving STAs) are allocated.

[0113] An RU may include multiple subcarriers (or tones). An RU may be used when transmitting signals to multiple STAs based on the OFDMA technique. An RU may also be defined when transmitting a signal to a single STA. Resources may be allocated in RU units for the non-legacy STF, non-legacy LTF, and Data field.

[0114] Applicable RU sizes may be defined depending on the PPDU bandwidth. RUs may be defined to be the same or different for applicable PPDU formats (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80 MHz PPDU, the RU arrangements for HE PPDU and EHT PPDU may be different from each other. The applicable RU size, number of RUs, RU locations, DC (direct current) subcarrier locations and numbers, null subcarrier locations and numbers, and guard subcarrier locations and numbers for each PPDU bandwidth may be referred to as a tone plan. For example, a tone plan for a wide bandwidth may be defined as multiple repetitions of a tone plan for a low bandwidth.

[0115] RUs of various sizes may be defined as 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs, 996-tone RUs, 2×996-tone RUs, 4×996-tone RUs, etc. An MRU (multiple RU) is distinct from multiple individual RUs and corresponds to a group of subcarriers consisting of multiple RUs. For example, one MRU may be defined as 52+26 tones, 106+26 tones, 484+242 tones, 996+484 tones, 996+484+242 tones, 2×996+484 tones, 3×996 tones, or 3×996+484 tones. Furthermore, the multiple RUs that make up one MRU may or may not be contiguous in the frequency domain.

[0116] The specific size of an RU may be reduced or expanded. Therefore, the specific size of each RU (i.e., the number of corresponding tones) in this disclosure is illustrative and not restrictive. Also, in this disclosure, the number of RUs within a given bandwidth (e.g., 20, 40, 80, 160, 320 MHz, ...) may vary depending on the size of the RU.

[0117] The names of the fields in the PPDU format of Fig. 7 are merely examples, and the scope of the present disclosure is not limited by the names. In addition, examples of the present disclosure may be applied to a new PPDU format in which some fields are excluded and / or some fields are added based on the PPDU format of Fig. 7, in addition to the PPDU format illustrated in Fig. 7.

[0118] FIG. 8 is a diagram illustrating an exemplary format of a trigger frame to which the present disclosure can be applied.

[0119] The trigger frame may allocate resources for one or more TB PPDU transmissions and request TB PPDU transmission. The trigger frame may also include other information required by the STA transmitting the TB PPDU in response. The trigger frame may include common information and a user information list field in the frame body.

[0120] The common information field may include information commonly applied to one or more TB PPDU transmissions requested by the trigger frame, such as a trigger type, a UL length, whether or not a subsequent trigger frame exists (e.g., More TF), whether or not a channel sensing (CS) is required, a UL bandwidth (BW), etc. Figure 8 illustrates an example of an EHT variant common information field format.

[0121] The 4-bit trigger type subfield may have values ​​from 0 to 15. Among them, the trigger type subfield values ​​0, 1, 2, 3, 4, 5, 6, and 7 are defined to correspond to basic, BFRP (Beamforming Report Poll), MU-BAR (multi user-block acknowledgement request), MU-RTS (multi user-request to send), BSRP (Buffer Status Report Poll), GCR (groupcast with retries) MU-BAR, BQRP (Bandwidth Query Report Poll), and NFRP (NDP Feedback Report Poll), respectively, and the values ​​8 to 15 are defined to be reserved.

[0122] The trigger dependent common info subfield of the common information may include information that is selectively included based on the trigger type.

[0123] A special user info field may be included in the trigger frame, which does not include user-specific information and contains extended common information not provided in the common information field.

[0124] The user info list contains zero or more user info fields. Figure 8 illustrates an example of an EHT variant user info field format.

[0125] The AID12 subfield basically indicates that it is a user information field for the STA having the corresponding AID. In addition, if the AID12 field has a predetermined specific value, it may be used for other purposes, such as allocating a random access (RA)-RU or being configured in the form of a special user information field. The special user information field is a user information field that does not include user-specific information but includes extended common information that is not provided in the common information field. For example, the special user information field may be identified by an AID12 value of 2007, and a special user information field flag subfield in the common information field may indicate whether the special user information field is included.

[0126] The RU allocation subfield can indicate the size and location of the RU / MRU. For this purpose, the RU allocation subfield can be interpreted together with the PS160 (primary / secondary 160 MHz) subfield of the user information field, the UL BW subfield of the common information field, etc.

[0127] WLAN Sensing Procedure

[0128] The sensing procedure refers to a procedure for acquiring cognitive information about the surrounding environment based on information about the channel environment (or state) included in a signal transmitted from a transmitting end to a receiving end. Each STA can provide additional services that can be applied in various ways to real life based on the information about the surrounding environment acquired through the sensing procedure.

[0129] Here, the information about the surrounding environment may include, for example, gesture recognition information, fall detection information, intrusion detection information, user motion detection, health monitoring information, or pet movement detection.

[0130] The sensing procedure may comprise at least one of a sensing session setup phase, a sensing measurement setup phase, a sensing measurement instance phase, a sensing measurement setup termination phase, and a sensing session termination phase.

[0131] Here, a sensing session may be defined as one period of receiving / measuring a sensing signal after the sensing signal is transmitted, and may be composed of one or more sensing measurement instances.

[0132] A sensing session may consist of multiple sub-sessions, each of which may include a measurement phase and a reporting phase, where a sub-session may be referred to as a sensing burst, a (sensing) measurement instance, or a measurement burst.

[0133] An STA that initiates a sensing procedure by sending a sensing measurement setup request frame or the like can be called a sensing initiator, and an STA that responds to the sensing initiator and participates in the sensing procedure (or sensing session) can be called a sensing responder.

[0134] The role of a STA that initiates or participates in a sensing procedure may be a sensing transmitter or / and a sensing receiver. The sensing transmitter refers to a STA that transmits a PPDU used for measurement in the sensing procedure, and the sensing receiver refers to a STA that receives the PPDU transmitted from the sensing transmitter in the sensing procedure and obtains a measurement result based on the PPDU.

[0135] Sensing Measurement Reporting Procedure

[0136] The final stage of a TB (triggered-based) sensing measurement instance may be a reporting stage. In the reporting stage of a TB sensing measurement instance, the sensing measurement results may be reported. The reporting stage can be divided into a basic reporting stage and a threshold-based reporting stage.

[0137] For a sensing responder that is a sensing receiver in the basic reporting phase, the reporting phase may exist in the TB sensing measurement exchange when the sensing measurement report request field value in the sensing measurement request frame is set to 1.

[0138] In the basic reporting phase, the sensing initiator can send a sensing report trigger frame that assigns RUs to one or more sensing receivers to obtain sensing measurement report frames containing sensing measurement results. Upon receiving the sensing report frame, the sensing responder can consistently send a sensing measurement report frame containing the sensing measurement results along with a measurement exchange ID corresponding to the current sensing measurement exchange or a previous sensing measurement exchange across all TB sensing measurement exchanges with the same measurement exchange ID.

[0139] Threshold-based reporting may be present in a TB sensing measurement exchange in which the sensing responder plays the role of the sensing receiver. The sensing initiator may implement threshold-based reporting to search for sensing responders with CSI change values ​​greater than or equal to the CSI change threshold assigned to them in the sensing measurement request frame.

[0140] The sensing initiator can send a sensing report trigger frame to obtain a sensing measurement report frame containing measurement results from the sensing responder.

[0141] The threshold-based reporting phase should include a CSI variation reporting sub-phase and may further include a measurement reporting sub-phase. Only sensing responders reporting CSI variation values ​​greater than or equal to the assigned CSI variation threshold can participate in the measurement reporting sub-phase.

[0142] When the sensing responder's sensing measurement report frame falls under the SI2SR (sensing initiator-to-sensing response) NDP of the current sensing measurement exchange, the CSI variation value determined by the sensing responder may represent a quantified difference between the currently measured CSI and the last reported CSI from the sensing responder (Case A).

[0143] When the sensing responder's sensing measurement report frame corresponds to the SI2SR NDP of the previous sensing measurement exchange, the CSI variation value may represent the quantified difference between the measured CSI of the previous sensing measurement exchange and the last reported CSI (Case B).

[0144] In threshold-based reporting, the sensing responder must be consistently in case A or case B in all subsequent TB sensing measurement exchanges that fall under the same sensing measurement session.

[0145] The CSI variation value should be in a closed interval between 0 and 1 (i.e., 0≦CSI variation value≦1), and a larger CSI variation value may reflect a larger CSI variation value. A CSI variation value of 0 may represent a case where the CSI variation is less than a certain degree that remains unchanged in all subsequent sensing measurement exchanges corresponding to the same sensing measurement session.

[0146] A CSI variation value of 1 may represent a case where the CSI variation is greater than a certain degree that remains unchanged in all subsequent sensing measurement exchanges corresponding to the same sensing measurement session.

[0147] The CSI fluctuation threshold for each sensing responder to be compared with the CSI fluctuation value should be determined by the sensing initiator and transmitted to each sensing responder in the sensing measurement request frame. Different sensing responders may have different thresholds set by the sensing initiator.

[0148] When the CSI fluctuation threshold field of the sensing measurement request frame sent by the sensing initiator is set to a value between 0 and 10 and the status code field of the corresponding sensing measurement response frame sent by the sensing responder is set to “SUCCESS,” the sensing initiator can send a sensing threshold-based report trigger frame to the sensing responder that supports threshold-based reporting in the CSI fluctuation reporting subphase to obtain a CSI fluctuation feedback value.

[0149] A sensing responder that supports threshold-based reporting may transmit a sensing CSI fluctuation feedback frame containing a CSI fluctuation feedback value to the SIFS after receiving a sensing threshold-based reporting trigger frame in the assigned RU.

[0150] In the measurement reporting subphase, for all sensing responders whose reported CSI variation feedback value is greater than or equal to the CSI variation threshold, the sensing initiator may transmit a sensing report trigger frame allocating an RU to the corresponding sensing responder SIFS after receiving the sensing measurement report frame including the CSI variation feedback. Otherwise, the sensing initiator does not need to transmit a sensing report trigger frame to the corresponding sensing responder.

[0151] A sensing responder that provides a CSI fluctuation feedback value greater than or equal to the threshold may transmit a sensing measurement report frame containing the measurement results to the sensing initiator of the assigned RU when triggered by the sensing report trigger frame.

[0152] A sensing responder that fails to receive a sensing report trigger frame in the threshold-based reporting stage may not transmit a sensing measurement report frame containing measurement results to the sensing initiator.

[0153] For example, the threshold-based reporting step may be implemented as shown in Fig. 11(a). After the NDPA (i.e., NDP announcement frame) sounding step, the sensing initiator may transmit a sensing trigger frame (e.g., a sensing threshold-based reporting trigger frame) to the sensing responders (e.g., sensing receiver 1 and sensing receiver 2) in the CSI variation reporting substep to request sensing measurement results.

[0154] If the CSI variation value reported in the measurement reporting subphase exceeds the CSI variation threshold, the sensing initiator can transmit a sensing report trigger frame. The sensing receiver 1 that has transmitted a CSI variation feedback value that exceeds the threshold can transmit a sensing measurement report frame to the sensing initiator.

[0155] Method for transmitting and receiving sensing threshold-based report trigger frames - Patents.com

[0156] In sub-7 GHz WLAN sensing, a basic (or general) reporting phase and a threshold-based reporting phase may be supported. For example, the basic reporting phase may include receiving feedback via a report sensing trigger frame. The threshold-based reporting phase may include receiving feedback via a report sensing trigger frame by comparing a CSI variation value with a threshold.

[0157] In this case, the report sensing trigger frame may be used to request CSI feedback as well as CSI variation feedback. Therefore, when transmitting the report sensing trigger frame, a method for indicating whether the trigger frame requests CSI feedback or CSI variation feedback needs to be defined. The following describes the method for indicating whether the report sensing trigger frame requests CSI feedback or CSI variation feedback.

[0158] 9 and 10, the first STA may be a non-AP STA that is a sensing responder (or / and sensing receiver), and the second STA may be an AP that is a sensing initiator (or / and sensing sender). However, this is merely an example, and each of the first STA and the second STA may be embodied by one of a non-AP STA and an AP, and the roles of each STA may also be interchangeable.

[0159] FIG. 9 is a diagram illustrating an operation performed by a first STA according to an embodiment of the present disclosure.

[0160] The first STA may receive a first sensing trigger frame including a sensing trigger subtype field from the second STA (S910).

[0161] Here, the value of the trigger type subfield of the first sensing trigger frame may be set to 8. That is, the trigger type subfield of the first sensing trigger frame may indicate that the type of the trigger frame is a sensing / ranging trigger frame.

[0162] The value of the fifth bit (B4) of the trigger dependent common information subfield of the first sensing trigger frame (i.e., sensing subfield) may be set to 1. That is, the sensing subfield may indicate that the corresponding trigger frame is a sensing trigger frame among a sensing trigger frame or a ranging trigger frame.

[0163] Based on the first sensing trigger frame, the first STA may transmit a first feedback frame associated with a first null data physical protocol data unit (PPDU) (NDP) received from the second STA to the second STA (S920).

[0164] Specifically, the first STA may receive an NDP announcement frame and a first NDP based on the NDP announcement frame from the second STA during the NDP sounding step, and may transmit a first feedback frame associated with the first NDP to the second STA based on the first sensing trigger frame.

[0165] Here, the information included in the first feedback frame may differ depending on whether the sensing trigger subtype field indicates a threshold-based report or a sensing report.

[0166] That is, the information included in the first feedback frame may differ depending on whether the trigger frame received from the second STA is a sensing threshold-based reporting trigger frame or a sensing reporting trigger frame.

[0167] As an example of the present disclosure, based on the sensing trigger subtype field indicating sensing threshold-based reporting (i.e., based on the sensing trigger subtype field value being set to 2), the first feedback frame may include channel state information (CSI) variation information.

[0168] That is, when the first STA receives a sensing threshold-based reporting trigger frame from the second STA in the CSI variation reporting subphase, the first STA can transmit a first feedback frame (i.e., a sensing CSI variation feedback frame) including a CSI variation (feedback) value to the second STA.

[0169] The CSI variation value may refer to a difference between the CSI based on the first NDP and the CSI based on the second NDP. The second NDP may refer to the NDP that the first STA last received from the second STA before the first NDP was transmitted. That is, the first STA may report to the second STA a difference between the CSI based on the previously received second NDP and the CSI based on the first NDP.

[0170] Here, the first STA can receive a specific frame (e.g., a sensing measurement request frame) including information about the threshold from the second STA, and can transmit a response frame (e.g., a sensing measurement response frame) to the specific frame to the second STA, thereby receiving a first trigger frame from the second STA.

[0171] That is, when the agreement on the threshold is completed, the first STA can receive a sensing threshold-based report trigger frame from the second STA.

[0172] For example, if the CSI variation value reported by the first STA is equal to or greater than a threshold, the first STA may receive a second sensing trigger frame from the second STA in the measurement reporting subphase. In this case, the second sensing trigger frame may be a sensing report trigger frame. The first STA may transmit a second feedback frame (i.e., a second feedback frame including CSI based on the first NDP) triggered by the second sensing trigger frame to the second STA.

[0173] As yet another example, the first STA may not receive the second sensing trigger frame from the second STA based on the CSI variation value being less than the threshold, i.e., if the CSI variation value is less than the threshold, the subsequent measurement reporting subphase may not be present.

[0174] As yet another example of the present disclosure, based on the sensing trigger subtype field indicating a sensing report (i.e., based on the sensing trigger subtype field value being set to 3), the first feedback frame may include CSI based on the first NDP.

[0175] That is, when the first STA receives a sensing report trigger frame from the second STA, the first STA can transmit a first feedback frame (i.e., a sensing measurement report frame) including CSI obtained by measuring the first NDP to the second STA.

[0176] As yet another example of the present disclosure, the sensing trigger subtype field may indicate an SR2SR (sensing responder to sensing responder) sounding procedure based on the sensing trigger subtype field value being set to 4. That is, upon receiving an SR2SR sounding trigger frame, the first STA may perform an SR2SR sounding procedure with other non-AP STAs.

[0177] FIG. 10 is a diagram illustrating an operation performed by a second STA according to an embodiment of the present disclosure.

[0178] The second STA can transmit a first sensing trigger frame including a sensing trigger subtype field to at least one STA (S1010).

[0179] Specifically, the second STA may transmit an NDP announcement frame and an NDP based on the NDP announcement frame to at least one STA during the NDPA sounding step. After transmitting the NDP, the second STA may transmit a first sensing trigger frame to at least one STA SIFS later.

[0180] The second STA may receive a first feedback frame associated with a first NDP (transmitted by the second STA) based on the first trigger frame from at least one STA (S1020).

[0181] For example, if the sensing trigger subtype field indicates that the sensing threshold-based report is to be performed, the first feedback frame transmitted by the first STA among the at least one STA may include a CSI variation value.

[0182] For example, if the CSI variation value transmitted by the first STA is equal to or greater than a threshold, the second STA may transmit a second sensing trigger frame to the first STA, and the second STA may receive a second feedback frame based on the second sensing trigger frame from the first STA.

[0183] As another example, if the CSI variation value transmitted by the first STA is less than a threshold, the second STA may not transmit a second sensing trigger frame to the first STA, whereas if the CSI variation value transmitted by another STA is equal to or greater than a threshold, the second STA may transmit a second sensing trigger frame to the other STA.

[0184] Hereinafter, a method for requesting CSI feedback or CSI variance feedback using a sensing trigger frame will be described in detail.

[0185] Example 1

[0186] The trigger frame used in the sensing measurement procedure may be defined based on a ranging trigger frame.

[0187] Since the sensing trigger frame variant is configured based on the ranging trigger frame variant, the trigger type subfield value (e.g., 8) corresponding to the ranging trigger frame variant and the sensing trigger frame variant may be the same.

[0188] That is, if the trigger type subfield value of a trigger frame is 8, the trigger frame may be a ranging trigger frame or a sensing trigger frame. If the trigger type subfield value of a trigger frame is 8, the trigger dependent common information subfield of the trigger frame may indicate whether the trigger frame is a ranging trigger frame or a sensing trigger frame.

[0189] That is, since the ranging trigger frame and the sensing trigger frame use the same trigger type subfield, the sensing trigger frame may include a trigger dependent common information subfield for indication of the sensing trigger frame variant.

[0190] For example, the indication of the sensing trigger frame may be performed by a reserved bit (B4) included in the trigger dependent common information subfield of the ranging trigger frame. That is, the fifth bit (B4) of the trigger dependent common information subfield may be used to inform the sensing STA whether the trigger frame is a sensing trigger frame.

[0191] For example, the trigger dependent common information subfield of the sensing trigger frame may be configured as shown in (b) of Figure 11. For example, when the sensing subfield (B4) value of the trigger dependent common information subfield is set to 1, this may indicate that the trigger frame is a sensing trigger frame (i.e., the variant of the trigger frame is a sensing trigger variant). When the sensing subfield (B4) value is set to 0, this may indicate that the trigger frame is a ranging trigger frame.

[0192] For example, the sixth bit (B7) to the eighth bit (B7) of the trigger dependent common information subfield may be configured as a token field, and when the sensing subfield (B4) value is set to 1, the token field may be interpreted as a measurement setup (or session).

[0193] Example 2

[0194] The subvariant of the sensing trigger frame may be indicated by a sensing trigger subtype subfield. As an example, the sensing trigger subtype field may be defined as shown in Table 1.

[0195] [Table 1]

[0196] The sensing trigger subtype field value included in the report trigger frame used to request CSI feedback measured in the sensing measurement phase may be set to, but is not limited to, 2 or 3. The report sensing trigger frame may be used to request channel information (e.g., CSI, etc.) measured in the sensing measurement phase from the sensing responder. Here, the report sensing trigger frame may be used to request CSI or CSI variation information in the basic (or general) reporting phase and the threshold-based reporting phase.

[0197] Therefore, in order to indicate whether the information requested in the report sensing trigger frame is CSI or CSI variation, the user field of the report sensing trigger frame may be configured as shown in FIG. 11(c).

[0198] The user information field of the report sensing trigger frame may include a CSI variation or report type subfield.

[0199] As an example, when a report sensing trigger frame is used for basic (or general) reporting (i.e., when used to request CSI feedback), the value of the CSI variation or report type subfield defined in the 40th bit (B39) of the user information field may be set to 0 (or 1).

[0200] As yet another example, if the report sensing trigger frame is used in the threshold reporting stage to request a CSI variation value, the value of the CSI variation or report type subfield may be set to 1 (or 0).

[0201] The responding STA can confirm the feedback type requested by the sensing initiator (or AP) by the CSI variation or report type subfield included in the user information field of the report sensing trigger frame.

[0202] Furthermore, a CSI variation or report type subfield may be defined by reserved bits in the user information field, which allows for report type indication without increasing overhead.

[0203] As an example of the present disclosure, a report sensing trigger frame for requesting a CSI variation report for a CSI-criticality report may be defined. To define the sensing trigger frame for requesting a CSI variation report, the sensing trigger subtype subfield may be defined as shown in Table 2.

[0204] [Table 2]

[0205] Here, the sensing trigger subtype field value for indicating CSI variation reporting may be set to another value (e.g., 2), and the sensing trigger subtype field value for indicating CSI reporting (e.g., basic reporting) may also be set to another value (e.g., 3). As described above, the CSI variation reporting subvariant defined for threshold-based reporting may be configured in the same format as the reporting subvariant for CSI reporting.

[0206] In addition to CSI variation reporting, an additional sub-variant for reporting based on SR2SR (sensing responder to sensing responder) sensing measurements may be defined. In this case, the additional sub-variant for reporting based on SR2SR sensing measurements may be indicated by a reserved value.

[0207] The embodiments described above are combinations of the components and features of the present disclosure in a predetermined form. Each component or feature should be considered optional unless otherwise explicitly stated. Each component or feature may be implemented without being combined with other components or features. It is also possible to combine some components and / or features to form embodiments of the present disclosure. The order of operations described in the embodiments of the present disclosure may be changed. Some components or features of one embodiment may be included in another embodiment, or may be replaced with corresponding components or features of another embodiment. It is clear that claims that do not have an explicit reference relationship in the claims may be combined to form embodiments, or may be included as new claims by amendment after filing.

[0208] It is obvious to those skilled in the art that the present disclosure can be embodied in other specific forms without departing from the essential features of the present disclosure. Therefore, the above detailed description should not be interpreted as limiting in any respect, but should be considered as illustrative. The scope of the present disclosure should be determined by reasonable interpretation of the appended claims, and any modifications within the equivalent scope of the present disclosure are included in the scope of the present disclosure.

[0209] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that cause a device or computer to perform operations according to the methods of various embodiments, as well as non-transitory computer-readable media on which such software or instructions are stored and executable on a device or computer. Instructions usable for programming a processing system to perform features described in this disclosure may be stored on or in a storage medium or computer-readable storage medium, and computer program products including such storage media may be used to embody features described in this disclosure. The storage medium may include, but is not limited to, high-speed random access memory such as DRAM, SRAM, DDR RAM, or other random access solid-state memory devices, and may include non-volatile memory such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. Memory optionally includes one or more storage devices located remotely from the processor. The memory, or alternatively, a non-volatile memory device within the memory, comprises a non-transitory computer-readable storage medium. The features described in this disclosure may be embodied in software and / or firmware stored on any one of a number of machine-readable media and capable of controlling the hardware of a processing system and allowing the processing system to interact with other mechanisms that utilize the results of embodiments of the present disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers. [Industrial Applicability]

[0210] The method proposed in this disclosure has been described mainly as being applied to an IEEE 802.11-based system, but it can also be applied to various wireless LANs or wireless communication systems other than the IEEE 802.11-based system.

Claims

1. A method performed by a first STA (station), receiving a first sensing trigger frame including a sensing trigger subtype field from a second STA; transmitting a first report frame associated with a first null data physical protocol data unit (NDP) received from the second STA based on the first sensing trigger frame to the second STA; The first report frame includes a channel state information (CSI) variation value based on the sensing threshold-based report being indicated by the sensing trigger subtype field; A method, wherein the first report frame includes sensing measurements based on the first NDP based on the sensing trigger subtype field indicating a sensing report.

2. the CSI variation value is a difference value between the CSI based on the first NDP and the CSI based on the second NDP; The method of claim 1 , wherein the second NDP is the NDP most recently received from the second STA before the first NDP is transmitted.

3. A sensing threshold-based report is indicated by the sensing trigger subtype field based on the sensing trigger subtype field value being set to 2; The method of claim 1 , wherein the sensing trigger subtype field indicates a sensing report based on the sensing trigger subtype field value being set to 3.

4. Based on the CSI fluctuation value being equal to or greater than a threshold, a second sensing trigger frame is received from the second STA; The method of claim 1 , wherein a second report frame based on the first NDP triggered by the second sensing trigger frame is transmitted to the second STA.

5. a specific frame including information about the threshold is received from the second STA, and a response frame for the specific frame is transmitted to the second STA, based on which the first sensing trigger frame is received from the second STA; The method of claim 4 , wherein the sensing trigger subtype field indicates sensing threshold-based reporting.

6. The method of claim 4 , wherein the second sensing trigger frame is not received from the second STA based on the CSI variation value being less than the threshold.

7. The value of the trigger type subfield of the first sensing trigger frame is set to 8; 2. The method of claim 1, wherein a value of a fifth bit (B4) of the trigger dependent common information subfield of the first sensing trigger frame is set to 1.

8. The method described in claim 1, wherein the sensing trigger subtype field indicates an SR2SR (sensing responder to sensing responder) sounding procedure based on the sensing trigger subtype field value being set to 4.

9. The method of claim 1 , wherein the first STA is a sensing responder and the second STA is a sensing initiator.

10. A first STA (station), at least one transceiver; at least one processor coupled to the at least one transceiver; The at least one processor: receiving a first sensing trigger frame including a sensing trigger subtype field from a second STA via the at least one transceiver; and transmitting a first report frame associated with a first null data physical protocol data unit (NDP) received from the second STA based on the first sensing trigger frame to the second STA via the at least one transceiver; The first report frame includes a channel state information (CSI) variation value based on the sensing threshold-based report being indicated by the sensing trigger subtype field; A first STA, wherein the first report frame includes sensing measurements based on the first NDP based on the sensing trigger subtype field indicating a sensing report.

11. A second STA (station), at least one transceiver; at least one processor coupled to the at least one transceiver; The at least one processor: Transmitting a first sensing trigger frame including a sensing trigger subtype field to at least one STA (station) via the at least one transceiver; and receiving, based on the first sensing trigger frame, a first report frame associated with a first null data physical protocol data unit (NDP) transmitted by the second STA from the at least one STA via the at least one transceiver; The first report frame includes a channel state information (CSI) variation value based on the sensing threshold-based report being indicated by the sensing trigger subtype field; A second STA, wherein the first report frame includes sensing measurements based on the first NDP based on the sensing trigger subtype field indicating a sensing report.

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