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

Abstract

A method and apparatus operating in a wireless LAN system are disclosed. A method performed by a first STA in a wireless LAN system according to an embodiment of the present disclosure includes receiving, from a second STA, a sensing trigger frame including a trigger-dependent common information subfield, and based on the sensing trigger frame, receiving an NDP from at least one STA or transmitting the NDP to the at least one STA. The trigger-dependent common information subfield includes a measurement session ID field and a sensing trigger subtype field, and the sensing trigger subtype field may include information indicating that the subtype of the sensing trigger frame is SR2SR sounding.

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 wireless LAN system.

Background Art

[0002] New technologies for improving the transmission rate, increasing the bandwidth, improving the reliability, reducing errors, and reducing latency have been introduced for wireless local area networks (WLANs). Among wireless LAN 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 into wireless LANs include enhancements for Very High-Throughput (VHT) of the 802.11ac standard and enhancements for High Efficiency (HE) of the IEEE 802.11ax standard.

[0003] To provide a more improved wireless communication environment, improvement technologies for Extremely High Throughput (EHT) are being discussed. For example, technologies for increased bandwidth, efficient utilization of multiple bands, Multiple Input Multiple Output (MIMO) to support increased spatial streams, and technologies for multi-access point (AP) coordination are being studied. In particular, various technologies for supporting traffic with low latency or real-time characteristics are being studied. In addition, new technologies for supporting ultra high reliability (UHR), including improvements or extensions of EHT technology, are being discussed.

Summary of the Invention

Problems to be Solved by the Invention

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

[0005] The technical problem of the present disclosure is to provide a method and an apparatus for performing sensing responder-to-sensing responder (SR2SR) sensing measurement in a wireless LAN system.

[0006] The technical problem to be achieved in the present disclosure is not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those having ordinary knowledge in the technical field to which the present disclosure belongs from the following description.

Means for Solving the Problems

[0007] As an embodiment of the present disclosure, a method performed by a first station (STA) in a wireless LAN system includes receiving, from a second STA, a sensing trigger frame including a trigger-dependent common information subfield; and based on the sensing trigger frame, receiving an NDP (null data physical protocol data unit (PPDU)) from at least one STA or transmitting the NDP to the at least one STA, wherein the trigger-dependent common information subfield includes a measurement session ID field and a sensing trigger subtype field, and the sensing trigger subtype field may include information indicating that the subtype of the sensing trigger frame is SR2SR (sensing responder to sensing responder) sounding.

[0008] As yet another example of the present disclosure, a method performed by a second station (STA) in a wireless LAN system includes transmitting a sensing trigger frame including a trigger-dependent common information subfield to at least one STA, transmitting a sensing report trigger frame requesting measurement information based on the NDP to a first STA among the at least one STA, and receiving a sensing measurement report frame from the first STA. The trigger-dependent common information subfield includes a measurement session ID field and a sensing trigger subtype field, and the sensing trigger subtype field may include information indicating that the subtype of the sensing trigger frame is SR2SR (sensing responder to sensing responder) sounding.

Advantages of the Invention

[0009] According to various embodiments of the present disclosure, a method and an apparatus for performing sensing measurement in a wireless LAN system can be provided.

[0010] According to various embodiments of the present disclosure, a method and an apparatus for performing SR2SR sensing measurement in a wireless LAN system can be provided.

[0011] According to various embodiments of the present disclosure, the accuracy of the sensing operation can be improved by performing a sensing measurement operation between sensing responders.

[0012] 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 of ordinary skill in the art to which the present disclosure pertains from the following description.

Brief Description of the Drawings

[0013] The accompanying drawings, which are included as a part of the detailed description to assist in understanding the present disclosure, provide examples of embodiments of the present disclosure and explain the technical features of the present disclosure together with the detailed description.

[0014]

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Best Mode for Carrying Out the Invention

[0015] Hereinafter, preferred embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed below together with the accompanying drawings is for explaining exemplary embodiments of the present disclosure, and is not for showing the only embodiments in which the present disclosure can be implemented. The following detailed description includes specific details in order to provide a complete understanding of the present disclosure. However, it is understood by those skilled in the art that the present disclosure can be implemented without such specific details.

[0016] In some cases, in order to avoid obscuring the concept of the present disclosure, well-known structures and devices may be omitted, or may be shown in the form of a block diagram centered on the core functions of each structure and device.

[0017] In the present disclosure, when a certain component is "connected", "coupled" or "connected" to another component, this may include not only a direct connection relationship, but also an indirect connection relationship in which there are further other components between them. Also, in the present disclosure, the terms "comprising" or "having" identify the presence of the recited 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.

[0018] In the present disclosure, terms such as "first" and "second" are used only for the purpose of distinguishing one component from another, and are not used to limit the components. Unless otherwise specified, they do not limit the order or importance among the components. Therefore, within the scope of the present disclosure, the first component in one embodiment can also be referred to as the second component in another embodiment, and similarly, the second component in one embodiment can also be referred to as the first component in another embodiment.

[0019] 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 forms are also intended to include the plural forms unless the context clearly dictates otherwise. The term "and / or" as used in this disclosure may refer to one of the related listed items or include any and all possible combinations of two or more of them. Also, in this disclosure, " / " between words has the same meaning as "and / or" unless otherwise specified.

[0020] The exemplifications of this disclosure may be applied to various wireless communication systems. For example, the exemplifications of this disclosure may be applied to a wireless LAN system. For example, the exemplifications of this disclosure may be applied to an IEEE 802.11a / g / n / ac / ax standard-based wireless LAN. Note that the exemplifications of this disclosure may be applied to a newly proposed IEEE 802.11bn (or, UHR) standard-based wireless LAN. Furthermore, the exemplifications of this disclosure may also be applied to a next-generation standard-based wireless LAN after IEEE 802.11bn. Also, the exemplifications of this disclosure may be applied to a cellular wireless communication system. For example, it may be applied to a cellular wireless communication system based on the technologies of the LTE (Long Term Evolution) series and the 5G NR (New Radio) series of the 3GPP (registered trademark) (3rd Generation Partnership Project) standard.

[0021] Hereinafter, the technical features to which the exemplifications of this disclosure can be applied will be described.

[0022] FIG. 1 is a block configuration diagram illustrating a wireless communication device according to an embodiment of this disclosure.

[0023] The first device 100 and the second device 200 illustrated in FIG. 1 may be referred to by various terms such as a terminal, a wireless device, a WTRU (Wireless Transmit Receive Unit), a UE (User Equipment), an MS (Mobile Station), a UT (user terminal), an MSS (Mobile Subscriber Station), an MSS (Mobile Subscriber Unit), an SS (Subscriber Station), an AMS (Advanced Mobile Station), a WT (Wireless terminal), or simply a user. Also, the first device 100 and the second device 200 may be referred to by various terms such as an access point (AP), a BS (Base Station), a fixed station, a Node B, a BTS (base transceiver system), a network, an AI (Artificial Intelligence) system, an RSU (road side unit), a repeater, a router, a relay, a gateway, etc.

[0024] The devices 100 and 200 illustrated in FIG. 1 may also be referred to as a station (STA). 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, a receiving STA, etc. For example, the STAs 110 and 200 may serve as an AP (access point) or a non-AP. That is, in the present disclosure, the STAs 110 and 200 may have the functions of an AP and / or a non-AP. When the STAs 110 and 200 have the AP function, they may simply be called an AP, and when the STAs 110 and 200 have the non-AP function, they may simply be called an STA. Also, in the present disclosure, an AP may be denoted as an AP STA.

[0025] Referring to FIG. 1, the first device 100 and the second device 200 can transmit and receive wireless signals using various wireless LAN technologies (e.g., IEEE 802.11 series). The first device 100 and the second device 200 may include interfaces for a medium access control (MAC) layer and a physical layer (PHY) that comply with the provisions of the IEEE 802.11 standard.

[0026] In addition, the first device 100 and the second device 200 can further support various communication standards other than wireless LAN technologies (e.g., 3GPP LTE series, 5G NR series standards, etc.). Also, the devices of the present disclosure may be embodied by various devices such as mobile phones, vehicles, personal computers, AR (Augmented Reality) equipment, VR (Virtual Reality) equipment, etc. Further, the STAs in this specification can support various communication services such as voice calls, video calls, data communication, autonomous driving, MTC (Machine-Type Communication), M2M (Machine-to-Machine), D2D (Device-to-Device), IoT (Internet-of-Things), etc.

[0027] The first device 100 includes one or more processors 102 and one or more memories 104, and may further include one or more transceivers 106 and / or one or more antennas 108. The processor 102 controls the memory 104 and / or the transceiver 106, and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts in the present disclosure. For example, after processing the information in the memory 104 to generate a first information / signal, the processor 102 can transmit a wireless signal including the first information / signal via the transceiver 106. Also, after receiving a wireless signal including a second information / signal via the transceiver 106, the processor 102 can store the information obtained from the signal processing of the second information / signal in the memory 104. The memory 104 may be connected to the processor 102 and can store various information related to the operation of the processor 102. For example, the memory 104 can store software code including instructions for executing part or all of the processes controlled by the processor 102 or for executing the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams in the present disclosure. Here, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., the IEEE 802.11 series). The transceiver 106 may be connected to the processor 102 and can 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 in the same sense as an RF (Radio Frequency) unit. In the present disclosure, the device can also mean a communication modem / circuit / chip.

[0028] The second device 200 includes one or more processors 202 and one or more memories 204, and may further include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206 and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in the present disclosure. For example, after processing the information in the memory 204 to generate third information / signals, the processor 202 may transmit a wireless signal including the third information / signals via the transceiver 206. Also, after receiving a wireless signal including fourth information / signals via the transceiver 206, the processor 202 may store the information obtained from the signal processing of the fourth information / signals 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 execute part or all of the processes controlled by the processor 202 or store software code including instruction words for implementing the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in the present disclosure. Here, the processor 202 and the memory 204 may be part of a communication 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 in the same sense as an RF unit. In the present disclosure, the device may also mean a communication modem / circuit / chip.

[0029] Hereinafter, the hardware elements of devices 100 and 200 will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors 102 and 202. For example, one or more processors 102 and 202 can implement one or more layers (for example, functional layers such as PHY and MAC). One or more processors 102 and 202 can generate one or more PDUs (Protocol Data Units) and / or one or more SDUs (Service Data Units) according to the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams in the present disclosure. One or more processors 102 and 202 can generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams in the present disclosure. One or more processors 102 and 202 can generate a signal (for example, a baseband signal) including PDU, SDU, message, control information, data, or information according to the functions, procedures, proposals, and / or methods in the present disclosure, and provide it to one or more transceivers 106 and 206. One or more processors 102 and 202 can receive a signal (for example, a baseband signal) from one or more transceivers 106 and 206, and obtain PDU, SDU, message, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams in the present disclosure.

[0030] One or more processors 102, 202 can be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. The one or more processors 102, 202 may be embodied by hardware, firmware, software, or a combination thereof. As an example, one or more ASICs (Application Specific Integrated Circuits), one or more DSPs (Digital Signal Processors), one or more DSPDs (Digital Signal Processing Devices), one or more PLDs (Programmable Logic Devices), or one or more FPGAs (Field Programmable Gate Arrays) may be included in the one or more processors 102, 202. The descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in this disclosure may be embodied using firmware or software, and the firmware or software may be embodied to include modules, procedures, functions, and the like. The firmware or software configured to execute the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in this disclosure may be included in the one or more processors 102, 202, stored in the one or more memories 104, 204, and driven by the one or more processors 102, 202. The descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in this disclosure may be embodied by firmware or software in the form of code, instruction words, and / or a set of instruction words.

[0031] One or more memories 104, 204 may be coupled to one or more processors 102, 202 and can store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. The one or more memories 104, 204 may be constituted by a ROM, a RAM, an EPROM, a flash memory, a hard drive, a register, a cache memory, a computer-readable storage medium, and / or a combination thereof. The one or more memories 104, 204 may be located inside and / or outside the one or more processors 102, 202. Also, the one or more memories 104, 204 may be coupled to the one or more processors 102, 202 by various techniques such as wired or wireless connections.

[0032] One or more transceivers 106, 206 can transmit user data, control information, radio signals / channels, etc. mentioned in the methods and / or operation sequence diagrams of the present disclosure to one or more other devices. One or more transceivers 106, 206 can receive user data, control information, radio signals / channels, etc. mentioned in the descriptions, functions, procedures, proposals, methods and / or operation sequence diagrams disclosed in the present disclosure from one or more other devices. For example, one or more transceivers 106, 206 may be connected to one or more processors 102, 202 and can transmit and receive radio signals. For example, one or more processors 102, 202 can control one or more transceivers 106, 206 to transmit user data, control information or radio signals to one or more other devices. Also, one or more processors 102, 202 can control one or more transceivers 106, 206 to receive user data, control information or radio signals from one or more other devices. Also, one or more transceivers 106, 206 may be connected to one or more antennas 108, 208, and one or more transceivers 106, 206 may be configured to transmit and receive user data, control information, radio signals / channels, etc. mentioned in the descriptions, functions, procedures, proposals, methods and / or operation sequence diagrams disclosed in the present disclosure via one or more antennas 108, 208. In the present disclosure, one or more antennas may be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports). One or more transceivers 106, 206 may convert received radio signals / channels, etc. from RF band signals to baseband signals in order to process received user data, control information, radio signals / channels, etc. using one or more processors 102, 202. One or more transceivers 106, 206 may convert user data, control information, radio signals / channels, etc. processed using one or more processors 102, 202 from baseband signals to RF band signals. For that purpose, one or more transceivers 106, 206 may include (analog) oscillators and / or filters.

[0033] For example, either one of STA100 and 200 can perform the intended operation of the AP, and the other one of STA100 and 200 can perform the intended operation of a non-AP STA. For example, the transceivers 106 and 206 in FIG. 1 can perform the transmission and reception operations of signals (e.g., packets or PPDUs (Physical layer Protocol Data Units) conforming to IEEE 802.11a / b / g / n / ac / ax / be / bn, etc.). Also, in the present disclosure, operations in which various STAs generate transmission and reception signals or perform data processing and calculations in advance for the transmission and reception signals may be performed by the processors 102 and 202 in FIG. 1. For example, an example of an operation of generating a transmission and reception signal or performing data processing and calculations in advance for the transmission and reception signal is 1) an operation of determining / acquiring / configuring / calculating / decoding / encoding bit information of fields (such as SIG (signal), STF (short training field), LTF (long training field), Data, etc.) included in the PPDU, 2) an operation of determining / configuring / acquiring time resources and frequency resources (e.g., subcarrier resources) used for fields (such as SIG, STF, LTF, Data, etc.) included in the PPDU, 3) an operation of determining / configuring / acquiring a specific sequence (e.g., pilot sequence, STF / LTF sequence, extra sequence applied to SIG) used for fields (such as SIG, STF, LTF, Data, etc.) included in the PPDU, 4) a power control operation and / or a power saving operation applied to the STA, 5) operations related to determining / acquiring / configuring / calculating / decoding / encoding an ACK signal, etc. Also, in the following example, various information (e.g., information regarding fields / sub-fields / control fields / parameters / power, etc.) used by various STAs for determining / acquiring / configuring / calculating / decoding / encoding transmission and reception signals may be stored in the memories 104 and 204 in FIG. 1.

[0034] Hereinafter, the downlink (DL) means a link for communication from an AP STA to a non-AP STA, and downlink PPDUs / packets / signals, etc. may be transmitted and received through 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. The uplink (UL) means a link for communication from a non-AP STA to an AP STA, and uplink PPDUs / packets / signals, etc. may be transmitted and received through 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.

[0035] FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure is applicable.

[0036] The structure of the wireless LAN system may be composed of a plurality of components. A wireless LAN that supports STA mobility transparent to the upper layer may be provided by the interaction of the plurality of components. A BSS (Basic Service Set) corresponds to the basic building block of the wireless LAN. In FIG. 2, an example is shown in which two BSSs (BSS1 and BSS2) exist and two STAs are included as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). In FIG. 2, the ellipse representing the BSS may be understood to represent the coverage area in which the STAs included in the BSS maintain communication. This area can be referred to as a BSA (Basic Service Area). When an STA moves outside the BSA, it can no longer communicate directly with other STAs within the BSA.

[0037] If the DS shown in Fig. 2 is not considered, the most basic type of BSS in a wireless LAN is an Independent BSS (IBSS). For example, an IBSS can have the smallest form consisting of only two STAs. For example, assuming that other components are omitted, BSS1 composed of only STA1 and STA2, or BSS2 composed of only STA3 and STA4 can each correspond to a typical example of an IBSS. Such a configuration is possible when STAs can communicate directly without an AP. Also, such a form of wireless LAN is not pre-planned and configured, but can be configured when a LAN is needed, and this can also be referred to as an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity that performs management functions centrally. That is, in an IBSS, STAs are managed in a distributed manner. In an IBSS, all STAs may be composed of mobile STAs, connection to a distributed system (DS) is not allowed, and it forms a self-contained network.

[0038] The membership of STAs in a BSS may be dynamically changed due to STAs joining or leaving, or STAs entering or leaving the BSS area. To become a member of a BSS, an STA can join the BSS using a synchronization process. To access all services of the BSS-based structure, an STA needs to be associated with the BSS. Such an association may be set dynamically and may include the use of a Distribution System Service (DSS).

[0039] In a wireless LAN, the direct STA-to-STA distance may be limited by the PHY performance. In some cases, such distance limits are sufficient, but in some cases, communication between STAs at a greater distance may be required. A distributed system (DS) may be configured to support extended coverage.

[0040] DS means a structure in which BSSs are interconnected. Specifically, as shown in FIG. 2, a BSS may exist as a component of an extended form of a network composed of a plurality of BSSs. DS is a logical concept and may be specified by the characteristics of the distributed system medium (DSM). In this connection, the wireless medium (Wireless Medium, WM) and the DSM may be logically separated. Each logical medium is used for different purposes and is used by different components. These media are not limited to being the same or different. The flexibility of the wireless LAN structure (DS structure or other network structures) can be explained by the fact that a plurality of media are logically different from each other. That is, the wireless LAN structure may be implemented in various ways, and the wireless LAN structure may be specifically identified independently by the physical characteristics of each implementation example.

[0041] DS can support mobile devices by providing seamless integration of a plurality of BSSs and providing the logical services necessary for handling addresses to destinations. In addition, DS may further include a component called a portal that acts as a bridge for connecting a wireless LAN to other networks (e.g., IEEE 802.X).

[0042] AP means an entity that enables access to the DS through the WM for the associated non-AP STA and also has the functionality of the STA. Data movement between the BSS and the DS can be performed via the AP. For example, the STAs 2 and 3 shown in FIG. 2 provide the function of enabling the associated non-AP STAs (STAs 1 and 4) to access the DS while having the functionality of the STA. Also, since all APs basically correspond to STAs, all APs are addressable entities. The address used by the 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 composed of an AP and one or more STAs can be referred to as an infrastructure BSS.

[0043] Data transmitted from one of the STAs associated with the AP to the STA address of the AP is always received at the uncontrolled port and may be processed by the IEEE 802.1X port access entity. Also, when the controlled port is authenticated, the transmitted data (or frame) can be transmitted to the DS.

[0044] An Extended Service Set (ESS) for providing a wider coverage may be set in the above-described DS structure.

[0045] An ESS means a network composed of a DS and BSSs, having an arbitrary size and complexity. An ESS can correspond to a set of BSSs connected to one DS. However, an ESS does not include a DS. The ESS network is characterized in that it appears as an IBSS at the LLC (Logical Link Control) layer. STAs included in an ESS can communicate with each other, and a mobile STA can transparently move from one BSS to another (within the same ESS) to the LLC. APs included in one ESS may have the same SSID (service set identification). The SSID is distinguished from the BSSID, which is the identifier of a BSS.

[0046] In a wireless LAN system, without making any assumptions about the relative physical positions of BSSs, any of the following forms are possible. BSSs may partially overlap, which is a commonly used form to provide continuous coverage. Also, BSSs do not have to be physically connected, and logically there is no limit to the distance between BSSs. Also, BSSs may be physically located at the same position, which may be used to provide redundancy. Also, one (or one or more) IBSS or ESS networks may physically exist in the same space as one (or one or more) ESS networks. This may correspond to the ESS network form in cases where an ad hoc network operates at the location where an ESS network exists, where wireless networks physically overlap by different organizations, or where two or more different access and security policies are required at the same location.

[0047] FIG. 3 is a diagram for explaining a link setup process to which the present disclosure is applicable.

[0048] In order for a STA to set up a link with a network and transmit and receive data, first, it must discover the network, perform authentication, establish an association, and carry out authentication procedures for security purposes. The link setup process can be referred to as the session start process or the session setup process. Also, the processes of discovery, authentication, association, and security setup in the link setup process can be collectively referred to as the association process.

[0049] In step S310, the STA can perform a network discovery operation. The network discovery operation may include the scanning operation of the STA. That is, in order for the STA to access the network, it must search for available networks to participate in. The STA must identify compatible networks before participating in a wireless network, and the process of identifying networks existing in a specific area is called scanning.

[0050] Scanning methods include active scanning and passive scanning. In FIG. 3, by way of example, a network discovery operation including an active scanning process is shown. In active scanning, the STA performing the scanning sends a probe request frame and waits for a response thereto in order to search for what APs exist in the vicinity while moving channels. The responder sends a probe response frame as a response to the probe request frame to the STA that sent the probe request frame. Here, the responder may be the STA that last sent a beacon frame in the BSS of the channel being scanned. Since the AP sends a beacon frame in the BSS, the AP becomes the responder, and in the IBSS, since the STAs within the IBSS send beacon frames alternately, the responder is not constant. For example, a STA that sends a probe request frame on channel 1 and receives a probe response frame on channel 1 saves the BSS-related information included in the received probe response frame, moves to the next channel (for example, channel 2), and can perform scanning in the same way (that is, send and receive probe requests / responses on channel 2).

[0051] Although not shown in FIG. 3, the scanning operation may be performed in a passive scanning manner. In passive scanning, the STA that performs scanning waits for beacon frames while moving channels. A beacon frame is one of the management frames defined in IEEE 802.11, which notifies the existence of a wireless network and is periodically transmitted so that the STA performing scanning can search for a wireless network and participate in the wireless network. In a BSS, the AP is responsible for periodically transmitting beacon frames, and in an IBSS, the STAs within the IBSS transmit beacon frames alternately. When the STA performing scanning receives a beacon frame, it stores the information about the BSS contained in the beacon frame and records the beacon frame information on each channel while moving to other channels. The STA that has received a beacon frame can store the BSS-related information contained in the received beacon frame and move to the next channel to perform scanning on the next channel in the same way. Comparing active scanning and passive scanning, active scanning has the advantage that the delay and power consumption are smaller than those of passive scanning.

[0052] After the STA discovers the network, the authentication process may be performed in step S320. Such an authentication process can be called the first authentication process in order to clearly distinguish it from the security setup operation in step S340 described later.

[0053] The authentication process includes a process in which the STA transmits an authentication request frame to the AP and, in response, the AP transmits an authentication response frame to the STA. The authentication frame used for authentication request / response corresponds to a management frame.

[0054] The authentication frame may include information regarding the authentication algorithm number, authentication transaction sequence number, status code, challenge text, RSN (Robust Security Network), Finite Cyclic Group, etc. This corresponds to an example of some of the information that may be included in the authentication request / response frame, and may be replaced by other information or may further include additional information.

[0055] The STA can send an authentication request frame to the AP. The AP can determine whether to permit authentication for the STA based on the information included in the received authentication request frame. The AP can provide the result of the authentication process to the STA using an authentication response frame.

[0056] After the STA is successfully authenticated, the association process may be performed at stage S330. The association process includes the process in which the STA sends an association request frame to the AP and, in response, the AP sends an association response frame to the STA.

[0057] For example, the association request frame may include information regarding various capabilities, beacon listen interval, SSID (service set identifier), supported rates, supported channels, RSN, mobility domain, supported operating classes, TIM (Traffic Indication Map) broadcast request, information regarding interworking service capabilities, and the like. For example, the association response frame may include information regarding various capabilities, status code, AID (Association ID), supported rates, EDCA (Enhanced Distributed Channel Access) parameter set, RCPI (Received Channel Power Indicator), RSNI (Received Signal to Noise Indicator), mobility domain, timeout interval (e.g., association comeback time), overlapping BSS scan parameters, TIM broadcast response, QoS (Quality of Service) map, and the like. This corresponds to an example of some of the information that may be included in the association request / response frame, and may be replaced by other information or further additional information may be included.

[0058] After the STA successfully associates with 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 RSNA (Robust Security Network Association) request / response. The authentication process in step S320 may be referred to as the first authentication process, and the security setup process in step S340 may simply be referred to as the authentication process.

[0059] The security setup process in stage S340 may include a process of setting up a private key using, for example, a 4-way handshake using EAPOL (Extensible Authentication Protocol over LAN) frames. Further, the security setup process may be performed by a security method not defined in the IEEE 802.11 standard.

[0060] FIG. 4 is a diagram for explaining a backoff process to which the present disclosure is applicable.

[0061] In a wireless LAN system, the basic access mechanism of MAC (Medium Access Control) is the CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) mechanism. The CSMA / CA mechanism, also known as the Distributed Coordination Function (DCF) of IEEE 802.11 MAC, basically adopts a "listen before talk" access mechanism. According to such a type of access mechanism, before starting transmission, the AP and / or STA can perform a Clear Channel Assessment (CCA) by sensing the wireless channel or medium for a predetermined time interval (e.g., DIFS (DCF Inter-Frame Space)). As a result of the sensing, if it is determined that the medium is in an idle status, frame transmission can be started through the medium. On the other hand, if the medium is sensed as being in an occupied or busy state, the AP and / or STA do not start their own transmission, but can set a delay period for medium access (e.g., a random backoff period) and wait, and then attempt frame transmission. By applying the random backoff period, it is expected that multiple STAs will attempt frame transmission after waiting for different times from each other, so collisions can be minimized.

[0062] In addition, the IEEE 802.11 MAC protocol provides the HCF (Hybrid Coordination Function). The HCF is based on the above-mentioned DCF and PCF (Point Coordination Function). PCF refers to a polling-based synchronous access method, in which all receiving APs and / or STAs periodically poll so that they can receive data frames. In addition, the HCF has EDCA (Enhanced Distributed Channel Access) and HCCA (HCF Controlled Channel Access). EDCA is an access method in which the provider makes the access method for providing data frames to multiple users be contention-based, and HCCA is to use a non-contention-based channel access method using a polling mechanism. In addition, the HCF includes a medium access mechanism for improving the QoS (Quality of Service) of a wireless LAN, and QoS data can be transmitted in both the Contention Period (CP) and the Contention Free Period (CFP).

[0063] Referring to FIG. 4, the operation based on the random backoff period will be described. When the medium that was in the occupied / busy state changes to the idle state, multiple STAs can attempt to transmit data (or frames). As a solution to minimize collisions, each STA can select a random backoff count and wait for the corresponding slot time before attempting to transmit. The random backoff count has a pseudo-random integer value and can be determined to be any one of the values in the range of 0 to CW. Here, CW is the contention window parameter value. The CW parameter is given an initial value of CWmin, but can take a value twice as large in the case of a transmission failure (for example, when an ACK for the transmitted frame cannot be received). When the CW parameter value reaches CWmax, data transmission can be attempted while maintaining the CWmax value until data transmission is successful, and when data transmission is successful, it is reset to the CWmin value. The CW, CWmin, and CWmax values are preferably set to 2 n -1 (n = 0, 1, 2,...).

[0064] When the random backoff process starts, the STA continues to monitor the medium while counting down the backoff slots according to the determined backoff count value. When the medium is monitored as being in the occupied state, the countdown stops and waits, and when the medium becomes idle, the remaining countdown resumes.

[0065] In the example of FIG. 4, when a packet to be transmitted arrives at the MAC of STA3, STA3 can confirm that the medium has been idle for only the DIFS and immediately transmit a frame. The remaining STAs monitor that the medium is in the occupied / busy state and wait. During this time, data to be transmitted may occur in each of STA1, STA2, and STA5. When each STA monitors that the medium is in the idle state, after waiting for only the DIFS, it can count down the backoff slots according to the random backoff count value it has selected. Assume that STA2 selects the minimum backoff count value and STA1 selects the maximum backoff count value. That is, an example is illustrated in which the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1 when STA2 finishes the backoff count and starts frame transmission. STA1 and STA5 stop counting down and wait for a while while STA2 occupies the medium. When STA2's occupation ends and the medium becomes idle again, STA1 and STA5 wait for only the DIFS and then resume the stopped backoff count. That is, after counting down the remaining backoff slots for only the remaining backoff time, frame transmission can be started. Since the remaining backoff time of STA5 is shorter than that of STA1, STA5 starts frame transmission. Data to be transmitted may also occur in STA4 while STA2 occupies the medium. From the perspective of STA4, when the medium becomes idle, after waiting for only the DIFS, it can count down according to the random backoff count value it has selected and start frame transmission. The example of FIG. 4 shows a case where the remaining backoff time of STA5 accidentally coincides with the random backoff count value of STA4. In this case, a collision may occur between STA4 and STA5. If a collision occurs, neither STA4 nor STA5 can receive an ACK and the data transmission will fail. In this case, STA4 and STA5 can select a random backoff count value after doubling the CW value and perform the count down.STA1 waits while the medium is busy due to the transmissions of STA4 and STA5. However, when the medium becomes idle, after waiting for only DIFS, if the remaining backoff time has elapsed, STA1 can start transmitting a frame.

[0066] As illustrated in FIG. 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 DIFS has elapsed since the medium became idle. Further, 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 the elapse of an IFS such as DIFS or PIFS (Point coordination function IFS). Subtype frames of the management frame include Beacon, Association request / response, Re - association request / response, Probe request / response, Authentication request / response, etc. A control frame is a frame used for controlling access to the medium. Subtype frames of the control frame include RTS (Request - To - Send), CTS (Clear - To - Send), ACK (Acknowledgment), PS - Poll (Power Save - Poll), BlockAck, BlockACKReq, NDP null (null data packet announcement), Trigger, etc. A control frame is transmitted after a backoff that occurs after DIFS has elapsed when it is not a response frame to a previous frame, and is transmitted without a backoff after SIFS (short IFS) has elapsed when it is a response frame to a previous frame. The type and subtype of a frame may be identified by the type field and subtype field within the frame control (FC) field.

[0067] A QoS (Quality of Service) STA can transmit a frame after performing a backoff that occurs after the expiration of AIFS (Arbitration IFS) for the access category (AC) to which the frame belongs, that is, AIFS[i] (where i is a value determined by the AC). Here, the frames for which AIFS[i] can be used can be data frames, management frames, or control frames that are not response frames.

[0068] FIG. 5 is a diagram for explaining a CSMA / CA-based frame transmission operation to which the present disclosure is applicable.

[0069] As described above, the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing in which a STA directly senses the medium. Virtual carrier sensing is for complementing 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 NAV (Network Allocation Vector). The NAV is a value that indicates to other STAs the time remaining until the medium becomes available for a STA that is currently using the medium or has the authority to use it. Therefore, the value set as the NAV corresponds to the period during which the use of the medium is planned by the STA that transmits the frame, and the STA that receives the NAV value is 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.

[0070] In the example of FIG. 5, assume that STA1 is about to transmit data to STA2, and STA3 is in a position where it can overhear part or all of the frames transmitted and received between STA1 and STA2.

[0071] In order to reduce the possibility of transmission collisions among multiple STAs in the CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames may be applied. In the example of FIG. 5, while the transmission of STA1 is being performed, as a result of the carrier sensing of STA3, it may be determined that the medium is idle. That is, STA1 may be a hidden node to STA3. Or, in the example of FIG. 5, while the transmission of STA2 is being performed, as a result of the carrier sensing of STA3, it may be determined that the medium is idle. That is, STA2 may be a hidden node to STA3. Before data transmission and reception between STA1 and STA2, by exchanging RTS / CTS frames, STAs outside the transmission range of either STA1 or STA2, or STAs outside the carrier sensing range for transmissions from STA1 or STA3, can be prevented from attempting to occupy the channel during the data transmission and reception between STA1 and STA2.

[0072] Specifically, STA1 can use carrier sensing to determine whether the channel is in use. In terms of physical carrier sensing, STA1 can determine the channel occupancy idle state based on the magnitude of the energy detected from the channel or the signal correlation. Also, in terms of virtual carrier sensing, STA1 can use the NAV (network allocation vector) timer to judge the occupancy state of the channel.

[0073] When the channel is idle at DIFS, STA1 can transmit an RTS frame to STA2 after performing backoff. When STA2 receives the RTS frame, it can transmit a CTS frame, which is a response to the RTS frame, to STA1 after SIFS.

[0074] Although STA3 cannot overhear the CTS frame from STA2, if it can overhear the RTS frame from STA1, STA3 can use the duration information included in the RTS frame to set the NAV timer for the subsequent consecutive frame transmission period (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame). Or, although STA3 cannot overhear the RTS frame from STA1, if it can overhear the CTS frame from STA2, STA3 can use the duration information included in the CTS frame to set the NAV timer for the subsequent consecutive frame transmission period (e.g., SIFS + data frame + SIFS + ACK frame). That is, when STA3 can overhear one or more of the RTS or CTS frames from at least one of STA1 or STA2, it can set the NAV based on this. When 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.

[0075] When STA1 receives the CTS frame from STA2, it can transmit a data frame to STA2 after SIFS from the time when the reception of the CTS frame is completed. When STA2 successfully receives the data frame, it can transmit an ACK frame, which is a response to the data frame, to STA1 after SIFS. When the NAV timer of STA3 expires, it can use carrier sensing to determine whether the channel is in use. When STA3 determines that the channel is not used by other terminals during the period from the expiration of the NAV timer to DIFS, it can attempt channel access after the contention window (CW) by random backoff has passed.

[0076] FIG. 6 is a diagram for explaining an example of a frame structure used in a wireless LAN system to which the present disclosure is applicable.

[0077] By an instruction or primitive (meaning a set of an instruction or parameters) from the MAC layer, the PHY layer can prepare an MPDU (MAC PDU) to be transmitted. For example, when receiving an instruction from the MAC layer requesting the start of transmission in the PHY layer, the PHY layer can switch to the transmission mode and configure and transmit the information (e.g., data) provided from the MAC layer in the form of a frame. Also, in the PHY layer, when detecting a valid preamble of the received frame, the PHY layer monitors the header of the preamble and sends an instruction to the MAC layer notifying the start of reception in the PHY layer.

[0078] In this way, information transmission / reception in a wireless LAN system is performed in the form of a frame, and for this purpose, a Physical layer Protocol Data Unit (PPDU) frame format is defined.

[0079] A basic PPDU may include a STF (Short Training Field), an LTF (Long Training Field), a SIG (SIGNAL) field, and a Data field. The most basic (e.g., non-HT (High Throughput) shown in FIG. 7) PPDU format may be composed of only an L-STF (Legacy-STF), an L-LTF (Legacy-LTF), an L-SIG (Legacy-SIG) field, and a Data field. Also, depending on the type of PPDU format (e.g., HT-mixed format PPDU, HT-greenfield format PPDU, VHT (Very High Throughput) PPDU, etc.), additional (or other types of) RL-SIG, U-SIG, non-legacy SIG fields, non-legacy STF, non-legacy LTF (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) may be included between the L-SIG field and the Data field. More specific matters will be described later with reference to FIG. 7.

[0080] 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. It can be said that the STF and the LTF are signals for synchronization and channel estimation of the OFDM physical layer.

[0081] The SIG field may contain various information related to PPDU transmission and reception. For example, the L-SIG field is composed of 24 bits, and the L-SIG field 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 the PPDU. For example, for non-HT, HT, VHT, or EHT PPDUs, the value of the Length field may be determined to be a multiple of 3. For example, for HE PPDUs, the value of the Length field may be determined to be a multiple of 3 + 1 or a multiple of 3 + 2.

[0082] The data field may include a SERVICE field, a PSDU (Physical layer Service Data Unit), PPDU TAIL bits, and, if necessary, padding bits. Some bits of the SERVICE field may be used for the synchronization of the descrambler at the receiving end. The PSDU corresponds to the MAC PDU defined at the MAC layer and may contain data generated / used at the upper layer. The PPDU TAIL bits may be used to return the encoder to the 0 state. The padding bits may be used to align the length of the data field to a predetermined unit.

[0083] The MAC PDU is defined by various MAC frame formats, and the basic MAC frame is composed of a MAC header, a frame body, and an FCS (Frame Check Sequence). The MAC frame is composed of MAC PDUs and may be transmitted / received by the PSDU in the data part of the PPDU format.

[0084] The MAC header includes a Frame Control field, a Duration / ID field, an Address field, etc. The Frame Control field may include control information necessary for frame transmission / reception. The Duration / ID field may be set to the time for transmitting the frame, etc. The address subfield can indicate the receiver address, transmitter address, destination address, and source address of the frame, and some address subfields may be omitted. It includes Sequence Control, QoS Control, and HT Control subfields, and the specific content of each subfield of the MAC header can be referred to in the IEEE 802.11 standard document.

[0085] The Null Data PPDU (NDP) format means a PPDU format that does not include a data field. That is, NDP means a frame format that includes the PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields, and, if present, further non-legacy SIG, non-legacy STF, non-legacy LTF) in the general PPDU format and does not include the remaining part (i.e., the data field).

[0086] FIG. 7 is a diagram showing an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure is applicable.

[0087] In standards such as IEEE 802.11a / g / n / ac / ax, various forms of PPDUs are used. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and Data fields. The basic PPDU format can also be referred to as the non-HT PPDU format (FIG. 7(a)).

[0088] The HT PPDU format (IEEE 802.11n) further includes HT-SIG, HT-STF, HT-LFT(s) fields in the basic PPDU format. The HT PPDU format shown in Fig. 7(b) can be referred to as the HT-mixed format. The HT-greenfield format PPDU may be further defined, which corresponds to a format composed of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and Data fields without including L-STF, L-LTF, and L-SIG (not shown).

[0089] An example of the VHT PPDU format (IEEE 802.11ac) further includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in the basic PPDU format (Fig. 7(c)).

[0090] An example of the HE PPDU format (IEEE 802.11ax) further includes RL-SIG (Repeated L-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), and PE (Packet Extension) fields in the basic PPDU format (Fig. 7(d)). Depending on the detailed illustration of the HE PPDU format, some fields may be excluded or their lengths may change. For example, the HE-SIG-B field is included in the HE PPDU format for multi-user (MU), and the HE-SIG-B is not included in the HE PPDU format for single-user (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 change to 8 us. The HE ER (Extended Range) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may change to 16 us. For example, RL-SIG may be configured the same as L-SIG. The receiving STA can determine that the received PPDU is an HE PPDU or an EHT PPDU described later based on the presence of RL-SIG.

[0091] The EHT PPDU format may include the EHT MU (multi-user) of FIG. 7(e) and the EHT TB (trigger-based) PPDU of FIG. 7(f). The EHT PPDU format is similar to the HE PPDU format in that it includes an RL-SIG following the L-SIG, but may include a U (universal)-SIG, an EHT-SIG, an EHT-STF, and an EHT-LTF following the RL-SIG.

[0092] The EHT MU PPDU of FIG. 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 either SU transmission or MU transmission. For example, the EHT MU PPDU may correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0093] The EHT TB PPDU of FIG. 7(f) omits the EHT-SIG compared to the EHT MU PPDU. A STA that has received 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.

[0094] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal SIGNAL), and EHT-SIG fields may be encoded and modulated so that they can also be demodulated and decoded in a legacy STA, and may be mapped based on a defined subcarrier frequency interval (e.g., 312.5 kHz). These can be referred to as pre-EHT modulated fields. Next, the EHT-STF, EHT-LTF, Data, and PE fields may be encoded and modulated so that they can be demodulated and decoded by an STA that has successfully decoded a non-legacy SIG (e.g., U-SIG and / or EHT-SIG) and obtained the information contained in the field, and may be mapped based on a defined subcarrier frequency interval (e.g., 78.125 kHz). These can be referred to as EHT modulated fields.

[0095] 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 modulated fields, and the HE-STF, HE-LTF, Data, and PE fields can be referred to as HE modulated 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 modulated fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields can be referred to as VHT modulated fields.

[0096] The U-SIG included in the EHT PPDU format of FIG. 7 may be composed, for example, based on 2 symbols (e.g., 2 consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG may have a duration of 4 us, and the U-SIG may have an overall duration of 8 us. Each symbol of the U-SIG may be used to transmit 26-bit information. For example, each symbol of the U-SIG may be transmitted and received based on 52 data tones and 4 pilot tones.

[0097] The U-SIG may be configured in units of 20 MHz. For example, when an 80 MHz PPDU is configured, the same U-SIG may be replicated in units of 20 MHz. That is, the same four U-SIGs may be included in the 80 MHz PPDU. When the bandwidth exceeds 80 MHz, for example, for a 160 MHz PPDU, the U-SIG in the first 80 MHz unit and the U-SIG in the second 80 MHz unit may be different from each other.

[0098] In the U-SIG, for example, A uncoded bits may be transmitted. The first symbol of the U-SIG (for example, the U-SIG-1 symbol) may transmit the first X bits of the total A-bit information, and the second symbol of the U-SIG (for example, the U-SIG-2 symbol) may transmit the remaining Y bits of the total A-bit information. The A-bit information (for example, 52 uncoded bits) may include a CRC field (for example, a 4-bit field) and a tail field (for example, a 6-bit field). The tail field may be used to terminate the trellis of the convolutional decoder and may be set to 0, for example.

[0099] The A-bit information transmitted by the U-SIG can be distinguished into version-independent bits and version-dependent bits. For example, the U-SIG may be included in a new PPDU format (for example, the 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, and some or all of the version-dependent bits may be different.

[0100] For example, the size of the version-independent bits of U-SIG may be fixed or variable. The version-independent bits may be assigned only to U-SIG-1 symbols, or may be assigned to both U-SIG-1 symbols and U-SIG-2 symbols. The version-independent bits and the version-dependent bits may be called by various names such as the first control bit and the second control bit.

[0101] For example, the version-independent bits of U-SIG may include a 3-bit physical layer version identifier, and this information can indicate the PHY version of the transmitted and received PPDU (e.g., EHT, UHR, etc.). The version-independent bits of U-SIG may include a 1-bit UL / DL flag field. The first value of the 1-bit UL / DL flag field is related to UL communication, and the second value of the UL / DL flag field is related to DL communication. The version-independent bits of U-SIG may include information regarding the length of the TXOP (transmission opportunity) and information regarding the BSS color ID.

[0102] For example, the version-dependent bits of U-SIG may include information that directly or indirectly indicates the type of PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).

[0103] The information necessary for the transmission and reception of PPDU may be included in U-SIG. For example, U-SIG may further include information regarding the bandwidth, information regarding the MCS scheme applied to non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.), information indicating whether a DCM (dual carrier modulation) scheme (e.g., reusing the same signal on two subcarriers) is applied to the non-legacy SIG to achieve an effect similar to frequency diversity, information regarding the number of symbols used for the non-legacy SIG, information regarding whether the non-legacy SIG is generated over the entire bandwidth, etc.

[0104] Some of the information necessary for PPDU transmission and reception may be included in the U-SIG and / or non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.). For example, information regarding the type of non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information regarding the length of the non-legacy LTF and the CP (cyclic prefix) length, information regarding the GI (guard interval) applied to the non-legacy LTF, information regarding preamble puncturing applicable to the PPDU, information regarding RU (resource unit) allocation, etc. may be included only in the U-SIG, may be included only in the non-legacy SIG, or may be indicated by a combination of the information included in the U-SIG and the information included in the non-legacy SIG.

[0105] Preamble puncturing can mean the transmission of a PPDU where there is no signal 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 a PPDU bandwidth of a predetermined size or more.

[0106] In the example of FIG. 7, non-legacy SIGs such as HE-SIG-B and EHT-SIG may include control information for the receiving STA. The non-legacy SIG 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 a previous SIG (e.g., HE-SIG-A, U-SIG, etc.).

[0107] Non-legacy SIGs such as HE-SIG-B and EHT-SIG may include a common field and user-specific fields. The common field and user-specific fields may be encoded separately.

[0108] In some cases, the common field may be omitted. For example, the common field may be omitted in a compression mode where non-OFDMA (orthogonal frequency multiple access) is applied, and multiple STAs can receive a PPDU (e.g., the data field of the PPDU) in the same frequency band. In a non-compression mode where OFDMA is applied, multiple users can receive a PPDU (e.g., the data field of the PPDU) in individual frequency bands.

[0109] The number of user-specific fields may be determined based on the number of users. One user block field may contain a maximum of two user fields. Each user field may be related to MU-MIMO allocation or non-MU-MIMO allocation.

[0110] The common field may include CRC bits and Tail bits. 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 may be set to 000000. The common field may include RU allocation information. The RU allocation information may include information regarding the location of the RUs allocated to multiple users (i.e., multiple receiving STAs).

[0111] An RU may include a plurality of subcarriers (or tones). An RU may be used when transmitting signals to a plurality of STAs based on the OFDMA technique. Also, an RU may be defined when transmitting a signal to one STA. Resources may be allocated in units of RUs for non-legacy STF, non-legacy LTF, and Data fields.

[0112] RUs of applicable sizes may be defined by the PPDU bandwidth. The RUs may be defined to be the same or different for the 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 of HE PPDU and EHT PPDU may be different from each other. The size, number, position of RUs, position and number of DC (direct current) subcarriers, position and number of null subcarriers, position and number of guard subcarriers, etc. applicable for each PPDU bandwidth can be referred to as a tone-plan. For example, the tone-plan for a wide bandwidth may be defined in the form of multiple repetitions of the tone-plan for a low bandwidth.

[0113] RUs of various sizes may be defined such as 26-tone RU, 52-tone RU, 106-tone RU, 242-tone RU, 484-tone RU, 996-tone RU, 2×996-tone RU, 4×996-tone RU, etc. An MRU (multiple RU) is distinguished from a plurality of individual RUs and corresponds to a group of subcarriers composed of a plurality of 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. Also, the plurality of RUs constituting one MRU may or may not be continuous in the frequency domain.

[0114] The specific size of the RU may be reduced or expanded. Therefore, in the present disclosure, the specific size of each RU (i.e., the number of corresponding tones) is exemplary rather than restrictive. Also, in the present disclosure, within a predetermined bandwidth (e.g., 20, 40, 80, 160, 320 MHz,...), the number of RUs may vary depending on the size of the RU.

[0115] In the PPDU format of FIG. 7, the names of the respective fields are exemplary and the scope of the present disclosure is not limited by the names. Also, the examples of the present disclosure may be applied to new PPDU formats in which some fields are excluded and / or some fields are added based on the PPDU format illustrated in FIG. 7 in addition to the PPDU format illustrated in FIG. 7.

[0116] FIG. 8 is a diagram showing an exemplary format of a trigger frame to which the present disclosure is applicable.

[0117] The trigger frame can allocate resources for one or more TB PPDU transmissions and request TB PPDU transmissions. The trigger frame may also include other information required by the STA that transmits the TB PPDU in response thereto. The trigger frame may include a common info field and a user info list field in the frame body.

[0118] The common info field may include information that is commonly applied to one or more TB PPDU transmissions requested by the trigger frame, such as trigger type, UL length, presence or absence of a subsequent trigger frame (e.g., More TF), presence or absence of a CS (channel sensing) requirement, UL BW (bandwidth), etc. FIG. 8 illustrates the EHT variant common info field format.

[0119] The 4-bit size trigger type subfield may have values from 0 to 15. Among them, the values 0, 1, 2, 3, 4, 5, 6, and 7 of the trigger type subfield 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 as reserved.

[0120] Among the common information, the trigger dependent common info subfield may include information selectively included based on the trigger type.

[0121] A special user info field may be included in the trigger frame. The special user info field does not include user specific information and includes extended common information not provided in the common information field.

[0122] The user information list includes one or more user info fields. In FIG. 8, the EHT variant user information field format is illustrated.

[0123] The AID12 subfield basically indicates that it is a user information field for the STA having the said AID. Additionally, when the AID12 field has a predetermined specific value, it may be utilized for other purposes such as allocating a Random Access (RA)-RU or being configured in the form of a special user info field. The special user info field is a user information field that does not contain user-specific information but contains extended common information not provided in the common information field. For example, the special user info field may be identified by an AID12 value of 2007, and the special user info field flag subfield in the common information field can indicate whether the special user info field is included or not.

[0124] The RU allocation subfield can indicate the size and location of the RU / MRU. For this purpose, the RU allocation subfield may be interpreted together with the PS160 (primary / secondary 160MHz) subfield of the user information field, the UL BW subfield of the common information field, etc.

[0125] WLAN Sensing Procedure

[0126] The sensing procedure means a procedure for obtaining awareness information about the surrounding environment based on information regarding the channel environment (or state) contained in the signal transmitted from the transmitting end to the receiving end. Each STA can provide additional services applicable in various forms in real life based on the information about the surrounding environment obtained by the sensing procedure.

[0127] Here, the information regarding 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, etc.

[0128] The sensing procedure may be composed of at least one of a sensing session setup stage, a sensing measurement setup stage, a sensing measurement instance stage, a sensing measurement setup termination stage, and a sensing session termination stage.

[0129] Here, a sensing session is defined as one cycle of receiving / measuring a sensing signal after the sensing signal is transmitted, and may be composed of one or more sensing measurement instances.

[0130] A sensing session may be composed of a plurality of sub - sessions, and each sub - session may include a measurement stage and a reporting stage. Here, the sub - session may be expressed as a sensing burst, a (sensing) measurement instance, or a measurement burst, etc.

[0131] An STA that starts the sensing procedure by transmitting a sensing measurement setup request frame, etc., can be called a sensing initiator, and an STA that participates in the sensing procedure (or, a sensing session) in response to the sensing initiator can be called a sensing responder.

[0132] The role of the STA that starts or participates in the sensing procedure may be a sensing transmitter or / and a sensing receiver. A sensing transmitter means a STA that transmits a PPDU used for measurement in the sensing procedure, and a sensing receiver means a STA that receives the PPDU transmitted from the sensing transmitter in the sensing procedure and obtains a measurement result based thereon.

[0133] SR2SR (sensing responder to sensing responder) Sensing Measurement Procedure

[0134] To perform sensing measurement, a sensing initiator (e.g., an AP) can send a sensing measurement request frame to a non-AP STA. The non-AP STA that receives the sensing measurement request frame can send to the sensing initiator in a sensing measurement response frame whether it will perform the sensing measurement. The sensing initiator and the sensing responder can perform a sensing measurement setup by the above-described procedure.

[0135] On the other hand, in addition to the sensing measurement procedure between the above-described AP and non-AP STAs, a sensing measurement procedure between non-AP STAs may be used. That is, in order to improve the performance, efficiency, and accuracy of sensing measurement, SR2SR (or, R2R (responder-to-responder)) may be performed in the next-generation wireless LAN system.

[0136] SR2SR can be used in either a TB (triggered-based) sounding procedure and / or an SBP (sensing by proxy) procedure. In the SBP procedure, a non-AP STA can become a sensing initiator and request the SBP procedure by sending an SBP request frame to the AP. The AP can start the SBP procedure by sending a response frame to the non-AP STA for the SBP procedure request frame.

[0137] Hereinafter, a trigger-based procedure for performing SR2SR sensing measurement and a method for instructing SR2SR sensing measurement will be described. Hereinafter, in FIGS. 9 and 10, the first STA (or the sensing responder) is a non-AP STA that is an SR2SR sensing transmitter or an SR2SR sensing receiver, and the second STA can mean the AP that is the sensing initiator. However, this is only an example, and the first STA and the second STA may be either a non-AP STA or an AP.

[0138] FIG. 9 is a diagram for explaining operations performed by the first STA according to an embodiment of the present disclosure.

[0139] The first STA can receive a sensing trigger frame including a trigger-dependent common information subfield from the second STA (S910).

[0140] Here, the trigger-dependent common information subfield may include a measurement session (or setup) ID field and a sensing trigger subtype field. The measurement session (or setup) ID field may include a measurement session ID corresponding to sensing measurement parameters related to SR2SR sounding based on the sensing trigger frame.

[0141] Here, the sensing measurement session can mean an agreement between the sensing initiator and the sensing responder on the operation parameters related to the sensing measurement exchange of a given measurement session ID.

[0142] And the sensing trigger subtype field may include information indicating that the subtype of the sensing trigger frame is SR2SR (sensing responder to sensing responder) sounding.

[0143] As an example, the sensing trigger subtype field value may be set to 4, which may mean that the trigger frame sent by the second STA is an SR2SR sounding trigger frame. However, this is only one example, and the sensing trigger subtype field value corresponding to the SR2SR sounding trigger frame may be defined as other values.

[0144] At this time, the first STA can send information indicating whether to assist with SR2SR sounding to the second STA. The information indicating whether to assist with SR2SR sounding may be included in the sensing field and sent to the second STA. At this time, the sensing field may be sent to the second STA by a sensing capability element (that is, a field related to the capability of the first STA related to sensing measurement).

[0145] (SR2SR sounding) The sensing trigger frame may include one sender user information field and one or more receiver user information fields.

[0146] Each of the one sender user information field and the one or more receiver user information fields may include a Tx / Rx field (that is, a field indicating the role of the first STA in the SR2SR sounding stage / procedure). And the one sender user information field may include a field indicating the number of HE (high throughput)-LTF (long training field) repetitions related to (SR2SR) NDP.

[0147] Furthermore, for example, the sender user information field may include the ID of the STA assuming the SR2SR sensing sender role. The one or more receiver user information fields may include the ID of the STA assuming the SR2SR sensing sender role and / or the ID of the STA assuming the SR2SR sensing receiver role.

[0148] Based on the sensing trigger frame, the first STA can receive the (SR2SR) NDP from at least one STA or transmit the (SR2SR) NDP to at least one STA (S920).

[0149] As an example, based on the Tx / Rx subfield included in the sender user information field of the sensing trigger frame indicating the role of the first STA as an SR2SR sensing sender, the first STA can transmit the (SR2SR) NDP to at least one STA. At this time, at least one STA may be indicated as an SR2SR sensing receiver by the receiver user information field in the SR2SR sounding stage.

[0150] As yet another example, based on the Tx / Rx subfield included in the specific receiver user information field corresponding to the first STA among at least one receiver user information field indicating the role of the first STA as an SR2SR sensing receiver, the first STA can receive the (SR2SR) NDP from among at least one STA that is an SR2SR sensing sender.

[0151] As an example, based on receiving a sensing report trigger frame requesting measurement information based on the (SR2SR) NDP from the second STA, the first STA can transmit a sensing measurement report frame to the second STA. As an example, the sensing measurement report frame may include a measurement session ID field, the ID of the SR2SR receiver / sender (such as the first STA, etc.), and CSI obtained based on the NDP.

[0152] FIG. 10 is a diagram for explaining the operations performed by the second STA according to an embodiment of the present disclosure.

[0153] The second STA can send a sensing trigger frame including a trigger-dependent common information subfield to at least one STA (i.e., at least one sensing responder) (S1010). Since the configuration of the sensing trigger frame has been described with reference to FIG. 9, duplicate explanations are omitted.

[0154] The second STA can send a sensing report trigger frame requesting measurement information based on the NDP to the first STA among the at least one STA (S1020). At this time, the role of the first STA in the SR2SR sounding stage may be an SR2SR sensing receiver.

[0155] The second STA can receive a sensing measurement report frame from the first STA (S1030).

[0156] Hereinafter, the SR2SR sensing procedure and the configuration of the frame related to the SR2SR sensing procedure will be specifically described.

[0157] The sensing initiator and the sensing responder that perform the sensing measurement can send and receive a sensing measurement request / response frame to / from each other for information exchange regarding the execution of the sensing measurement during the sensing measurement setup stage. At this time, as an example, the sensing measurement setup stage for performing the sensing measurement procedure may be performed as shown in FIG. 11.

[0158] As an example, as shown in FIG. 11, the sensing initiator (e.g., AP) can send a sensing measurement setup request frame to the sensing responder during the sensing measurement setup stage to request the sensing measurement.

[0159] The sensing measurement setup request frame may include information on sensing measurement parameters for performing sensing measurement. The sensing measurement parameters may include indication information for SR2SR measurement support. The sensing responder (e.g., non-AP STA) that receives the sensing measurement setup request frame can send a sensing measurement setup response frame including information on the presence or absence of SR2SR measurement support to the sensing initiator.

[0160] As an example of the present disclosure, Fig. 12(a) illustrates the format of a sensing measurement parameter field including an SR2SR subfield.

[0161] Here, the indication information for SR2SR measurement support may be indicated by the SR2SR subfield. The SR2SR subfield may be included in and transmitted in the sensing measurement parameter field of the sensing measurement parameter element.

[0162] As an example, the SR2SR subfield may be composed of 1 bit. When the SR2SR subfield value is set to 1 (or 0), this can indicate that SR2SR measurement is supported. When the SR2SR subfield value is set to 0 (or 1), this can indicate that SR2SR measurement is not supported. However, this is only one embodiment, and the bits of the SR2SR subfield and the corresponding indication information may be set differently from the above.

[0163] The sensing measurement setup request / response frame transmitted and received by the sensing initiator and the sensing responder for performing sensing measurement may include a sensing measurement parameter element.

[0164] When the SR2SR subfield is included in the sensing measurement setup request frame, this can indicate that the sensing initiator allows SR2SR measurement and can request the channel information between the sensing responders measured by the sensing responder from the sensing responder.

[0165] When the SR2SR subfield is included in the sensing measurement setup response frame, this can indicate that the sensing responder can receive the NDP sent by other sensing responders and estimate the channel information between (non-AP) STAs (i.e., perform SR2SR measurements).

[0166] When the value of the SR2SR subfield transmitted in the sensing measurement setup response frame is set to 0 or a non-supporting value, the sensing responder does not have to perform SR2SR measurements.

[0167] Through the sensing measurement setup between the sensing initiator (e.g., AP) and the sensing responder (e.g., non-AP STA), the AP can obtain information about non-AP STAs that support SR2SR measurements.

[0168] Example 1

[0169] The AP may perform a trigger-based sensing measurement procedure to perform sensing measurements by non-AP STAs that support SR2SR sensing measurements grasped through the sensing measurement setup.

[0170] As an example of the present disclosure, as shown in FIG. 13(a), the sensing initiator (e.g., AP) can trigger NDP transmission by transmitting a trigger frame to non-AP STA1 that operates as a sensing responder in the sensing measurement.

[0171] Based on the trigger frame, non-AP STA1 can send the NDP to non-AP STA2 that supports SR2SR sensing measurements. Non-AP STA2 can perform SR2SR sensing measurements based on the NDP.

[0172] Specifically, an AP that has identified a non-AP STA that supports SR2SR measurement through a sensing measurement setup can, in the sensing measurement procedure, transmit a trigger frame to non-AP STA1 to request NDP transmission in order to perform SR2SR measurement.

[0173] As an example, the trigger frame transmitted by the AP to request NDP transmission is a sensing trigger frame, and the sensing trigger subtype of the sensing trigger frame may be set / defined as a sounding sensing trigger variant.

[0174] As an addition or alternative, the sensing trigger subtype of the sensing trigger frame may be defined as a sensing trigger frame variant for SR2SR transmission. For example, the sensing trigger subtype of the sensing trigger frame may be defined as an SR2SR sensing variant or an SR2SR sounding trigger variant, etc.

[0175] For the convenience of the description of the present disclosure, the trigger frame is named a sounding sensing trigger variant, but it is not limited thereto. The trigger frame may be defined / named / set as a trigger frame for SR2SR measurement.

[0176] The sounding sensing trigger variant for performing SR2SR measurement may be defined / set as an SR2SR measurement / sounding variant. The sub-variant (or / and, subtype) of the sensing trigger frame may be indicated by the sensing trigger subtype included in the trigger-dependent common information sub-field of the sensing trigger frame.

[0177] As an example, the sensing trigger subtype subfield may be configured as shown in Table 1. However, this is only one example, and the sensing trigger frame sub-variant associated with SR2SR sounding may be mapped to a reserved value (for example, any one of 4 to 15).

[0178]

Table 1

[0179] As yet another example of the present disclosure, a sub-variant for SR2SR measurement may not be separately defined / set, and a sounding sub-variant may be applied / used. When transmitting the SR2SR sensing trigger sub-variant and the set trigger frame, the TA included in the trigger frame may be set to the address of the AP, and the RA may be set to a non-AP STA (for example, non-AP STA1) that transmits a broadcast ID / NDP. Here, the trigger frame may include one user field for the non-AP STA that transmits the NDP.

[0180] And the trigger frame may include an SR2SR sensing indication bit (for example, an SR2SR subfield) to indicate an SR2SR sensing measurement. At this time, the SR2SR sensing indication bit may be included in the trigger-dependent common information subfield of the trigger frame.

[0181] For example, the SR2SR subfield value may be composed of 1 bit. When the SR2SR subfield value is set to 1 (or 0), this can indicate that it supports SR2SR measurement. When the SR2SR subfield value is set to 0 (or 1), this can indicate that it does not support SR2SR measurement.

[0182] As shown in Fig. 13(a), the non-AP STA2 performing SR2SR sensing measurement receives a trigger frame (e.g., a value set in the SR2SR subfield included in the common information field of the trigger frame) transmitted by the AP for the SR2SR sensing measurement, and it can be seen that the SR2SR sensing measurement is performed.

[0183] Here, the trigger frame may include ID (identity) information (i.e., measurement setup ID) for confirming the sensing measurement related to the trigger frame for SR2SR measurement feedback. For this purpose, the measurement setup ID may be included and transmitted in the trigger-dependent common information field of the trigger frame.

[0184] As described above, the trigger frame set as the SR2SR sensing trigger / sounding (sub)variant is used to trigger NDP transmission and may include one user field.

[0185] As an example, the user field (for SR2SR) of the trigger frame may include AID information, BW / allocation information, "GI + LTF size (or / and type)" information, and NSS (number of spatial stream) information, etc.

[0186] Here, the AID information may include ID information for the non-AP STA to which the NDP is transmitted for SR2SR measurement.

[0187] And the BW / allocation information may include BW information for NDP transmission. The BW / allocation information may be composed of the same 2 bits (i.e., the bits indicating the BW for NDP transmission) as the UL BW in the common information field of the trigger frame. The BW for NDP transmission can indicate one of 20MHz, 40MHz, 80MHz, 160MHz, or 80 + 80MHz.

[0188] As yet another example, the BW / allocation information may be configured with 3 bits. At this time, the BW / allocation information can also indicate a BW of 320 MHz or more as the BW on which the NDP is transmitted.

[0189] Additionally or alternatively, a BW extension field may be used to indicate a BW of 320 MHz or more, and the BW extension field may be configured with 1 bit. As an example, when the BW extension field value is set to 1, this indicates a BW of 320 MHz, and when the BW extension field value is set to 0, this can indicate a BW less than 320 MHz.

[0190] As an example, the BW on which the NDP is transmitted as indicated by the BW / allocation information may be configured with a BW that is less than or equal to the UL BW of the common information field of the trigger frame.

[0191] As an example, the BW / allocation information on the user information field included in the trigger frame may include puncturing information. That is, the BW / allocation information may be configured with 5 bits to indicate puncturing information. The Non-AP STA can confirm the BW on which the NDP is transmitted from the UL BW subfield of the common information field of the trigger frame, and can confirm the punctured information within the BW from the BW / allocation information field.

[0192] The "GI + LTF size (or / and type)" information may be used to indicate information regarding the GI and LTF size used at the time of transmitting the NDP. Specifically, since the Non-AP STA transmits the NDP using the SU format, the GI and LTF size can be confirmed from the "GI + LTF size (or / and type)" information.

[0193] Here, the "GI + LTF size (or / and type)" information included in the user information field may be configured to be different from the "GI + LTF type" information transmitted in the common information field of the trigger frame.

[0194] As an example, the "GI + LTF size (or / and type)" information may be configured with 2 bits as shown in Table 2 below.

[0195]

Table 2

[0196] As yet another example of the present disclosure, when transmitting a trigger frame configured as an SR2SR sensing trigger (sub)variant, the "GI + LTF size subfield" of the common information field of the trigger frame may be configured by the above-described configuration (for example, the configuration according to Table 2, etc.). And the "GI + LTF size subfield" of the common information field of the trigger frame can indicate information regarding the GI and LTF type (or / and size) for NDP transmission using the SU format.

[0197] As an example, when the "GI + LTF size subfield" configured as described above is included in the common information field of the trigger frame, the "GI + LTF size subfield" may not be included in the user information field of the trigger frame.

[0198] The NSS information can indicate the number of spatial streams assigned at the time of NDP transmission. As an example, the NSS information may be configured with 3 bits and can indicate any one of 1 to 8 as the number of spatial streams.

[0199] Referring to FIG. 13(a), the non-AP STA1 that has received the SR2SR sensing trigger frame from the AP can transmit an NDP for SR2SR measurement to other non-AP STAs. At this time, the NDP may be configured using the SU PPDU format. For example, the NDP may be configured using the HE NDP format or the EHT NDP format.

[0200] Non-AP STA2 that has received the NDP transmitted by Non-AP STA1 can perform channel measurement between Non-AP STA1 and Non-AP STA2 using the received NDP.

[0201] Here, the Non-AP STA2 may be a STA that supports SR2SR measurement by a sensing measurement setup. Non-AP STA2 receives a trigger frame transmitted for the AP to request NDP transmission and can grasp that the SR2SR measurement procedure is to be performed. At this time, Non-AP STA1 and / or Non-AP STA2 can confirm from the user field included in the trigger frame that Non-AP STA1 transmits an NDP.

[0202] To receive the report of the channel information measured by Non-AP STA2, the AP can transmit a feedback request trigger frame to Non-AP STA2.

[0203] The above-described feedback request procedure may be performed in a sensing reporting phase. And the above-described feedback request procedure may support both an immediate feedback procedure and a delayed feedback procedure.

[0204] Non-AP STA2 that has received the feedback request trigger frame can transmit measurement information (e.g., CSI information) to the AP using the report-related parameters included in the feedback request trigger frame.

[0205] The CSI information transmitted by Non-AP STA2 may be transmitted to the AP in a sensing report frame. At this time, the sensing report frame may include ID information, AID, or UID (USID) of the receiving STA.

[0206] As shown in FIG. 13(a), each frame transmission may be performed at an SIFS interval, but is not limited thereto. Various types of IFSs may be considered for each frame transmission. As another example, for the transmission of a feedback request frame and a feedback report frame, an IFS with an interval larger than the SIFS may be applied.

[0207] Example 2

[0208] As shown in FIG. 13(b), when the AP transmits a trigger frame to perform SR2SR sensing measurement, the trigger frame may include a user field for a non-AP STA that performs SR2SR sensing measurement.

[0209] Specifically, the trigger frame may be a subvariant of the sensing trigger frame and may include information on the Tx non-AP STA and the Rx non-AP STA.

[0210] The indication for the subvariant may be performed by the sensing trigger subtype of the trigger-dependent common information subfield of the sensing trigger frame. As an example, a sounding subvariant for SR2SR measurement may be indicated by the sensing trigger subtype. As yet another example, when a new subvariant (or subtype) for SR2SR measurement is defined, one of the reserved values excluding the value corresponding to the existing subvariant in the sensing trigger subtype may be indicated as the new subvariant.

[0211] As an example, a sensing trigger frame with an SR2SR subvariant or a sounding subvariant set may include an SR2SR sensing indication bit (e.g., an SR2SR subfield) to indicate an SR2SR sensing measurement. Here, the SR2SR sensing indication bit may be included in and transmitted in the trigger-dependent common information subfield of the trigger frame.

[0212] For example, the SR2SR subfield may be composed of 1 bit. When the SR2SR subfield value is set to 1 (or 0), this can indicate that it supports the SR2SR measurement. When the SR2SR subfield value is set to 0 (or 1), this can indicate that it does not support the SR2SR measurement.

[0213] As an addition or alternative, the SR2SR subfield value may be set to 1 only during the SR2SR measurement, and may be set to 0 or reserved in other cases.

[0214] That is, in the sub-variant of the sensing trigger frame (i.e., ball, sounding, reporting, etc.) used for the SR2SR measurement, the SR2SR subfield value may always be set to 1.

[0215] As shown in FIG. 13(b), a non-AP STA that performs the SR2SR sensing measurement can confirm whether the SR2SR sensing measurement is to be performed from the trigger frame (e.g., the value set for the SR2SR subfield included in the dependent common information subfield) transmitted by the AP for the SR2SR sensing measurement.

[0216] Here, the trigger frame may include ID (identity) (i.e., measurement setup ID) information for confirming the sensing measurement related to the trigger frame for the SR2SR measurement feedback. For this purpose, the measurement setup ID may be included in the trigger dependent common information field of the trigger frame and transmitted.

[0217] As an example, as shown in FIG. 12(b), the trigger dependent common information field of the trigger frame may be configured. As an addition or alternative, the trigger dependent common information field may be composed of 2 bytes including the measurement setup ID.

[0218] As an addition or alternative, when performing SR2SR sensing measurements, a sounding sensing trigger frame may be used as the sensing trigger frame. At this time, a specific subfield of the user information field of the sensing trigger frame may be used to instruct non-AP STAs to perform SR2SR sensing.

[0219] The user information field of the sounding sensing trigger frame may include an SR2SR subfield. As an example, when the SR2SR subfield value is set to 1, this can indicate the execution of SR2SR measurements. When the SR2SR subfield value is set to 0 due to general sensing measurements being performed, this can indicate that SR2SR measurements are not to be performed.

[0220] Additionally, when performing SR2SR sensing measurements, an SR2SR Tx / Rx subfield may be defined as part of the user field of the sounding sensing trigger frame to indicate the NDP transmission STA and the NDP reception STA.

[0221] The SR2SR Tx / Rx subfield may be valid when the SR2SR subfield value included in the user information field is set to 1. As an example, in the case of a Tx STA (i.e., the STA that transmits the NDP), the SR2SR Tx / Rx subfield value (for transmissions and receptions by the Tx STA) may be set to 1 (or 0). In the case of an Rx STA (i.e., the STA that receives the NDP), the SR2SR Tx / Rx subfield value (for transmissions and receptions by the Rx STA) may be set to 0 (or 1). This is one example, and the SR2SR Tx / Rx subfield value may be set differently.

[0222] When the SR2SR subfield value is 0, the SR2SR Tx / Rx subfield may be considered as a disregard bit or reserved.

[0223] When transmitting the SR2SR / Sounding Sensing Trigger Subvariant, the TA may be set to the address of the AP that transmits the trigger frame, and the RA may be set to a broadcast ID or a multicast ID.

[0224] The SR2SR / Sounding Sensing Trigger Subvariant may include a user information field for STAs participating in the SR2SR sensing measurement. At this time, the user information field may be composed of user information fields for each of the Tx STA and the Rx STA performing the SR2SR measurement.

[0225] Each of the user information fields for each of the Tx STA and the Rx STA may include AID information, SR2SR Tx / Rx operation (or SR2SR role indication), BW / assignment information, "GI + LTF size (or / and type)" information, and NSS (number of spatial stream) information, measurement ID, and SR2SR subfields, etc.

[0226] Here, the AID information may include ID information for non-AP STAs for R2R measurement. The AID information may include an ID for the Tx non-AP STA or the Rx non-AP STA. The ID may include ID information for associated STAs or unassociated STAs.

[0227] The Tx / Rx operation or R2R role indication information may include information for indicating the role or Tx / Rx operation of the non-AP STA during R2R measurement.

[0228] As an example, the Tx / Rx operation or R2R role indication information may be composed of 1 bit. When the bit value corresponding to the Tx / Rx operation or R2R role indication information is set to 0 (or 1), this can indicate the Rx operation or the receiver role. And when the bit value corresponding to the Tx / Rx operation or R2R role indication information is set to 1 (or 0), this can indicate the Tx operation or the sender role.

[0229] The bit (or the field containing the bit) value corresponding to the Tx / Rx operation or R2R role indication information included in the user (information) field for the Tx non-AP STA may always be set to 1 (or 0). And the bit (or the field containing the release bit) value corresponding to the Tx / Rx operation or R2R role indication information included in the user (information) field for the Rx non-AP STA may always be set to 0 (or 1).

[0230] The BW / assignment information may include BW information for NDP transmission / reception (e.g., feedback). As described in Example 1, the BW / assignment information may be composed of the same 2 bits (i.e., the bits indicating the BW on which the NDP is transmitted) as the UL BW in the common information field of the trigger frame. The BW on which the NDP is transmitted can indicate one of 20 MHz, 40 MHz, 80 MHz, 160 MHz, or 80 + 80 MHz.

[0231] As yet another example, the BW / assignment information may be composed of 3 bits. At this time, the BW / assignment information can also indicate a BW of 320 MHz or more as the BW on which the NDP is transmitted.

[0232] As an example, the BW on which the NDP indicated by the BW / assignment information is transmitted may be composed of a BW that is smaller than or equal to the UL BW in the common information field of the trigger frame.

[0233] As an example, the BW / assignment information on the user information field included in the trigger frame may include puncturing information. That is, the BW / assignment information may be configured with 5 bits to indicate the puncturing information. The Non-AP STA can confirm the BW on which the NDP is transmitted from the UL BW subfield of the common information field of the trigger frame, and can confirm the information to be punctured within the BW from the BW / assignment information field.

[0234] As an example, since the BW information may be used identically to the UL BW information in the common information field, the user information field may not include the BW information.

[0235] The "GI+LTF size (or / and type)" information may be used to indicate information regarding the GI and LTF sizes used at the time of NDP transmission. Specifically, since the Non-AP STA transmits the NDP using the SU format, the GI and LTF sizes can be confirmed from the "GI+LTF size (or / and type)" information.

[0236] Here, the "GI+LTF size (or / and type)" information included in the user information field may be configured to be different from the "GI+LTF type" information transmitted in the common information field of the trigger frame.

[0237] As an example, the "GI+LTF size (or / and type)" information may be configured with 2 bits as shown in Table 3.

[0238] As yet another example of the present disclosure, at the time of transmitting a trigger frame set as an SBP / R2R sensing trigger (sub)variant, the "GI+LTF size subfield" of the common information field of the trigger frame may be configured by the above-described configuration (for example, the configuration according to Table 3, etc.).

[0239] Then, the "GI + LTF Size Sub - field" in the common information field of the trigger frame can indicate information regarding the GI and LTF type (or / and size) for NDP transmission using the SU format.

[0240] As an example, when the "GI + LTF Size Sub - field" configured as described above is included in the common information field of the trigger frame, the "GI + LTF Size Sub - field" may not be included in the user information field of the trigger frame.

[0241] The NSS information can indicate the number of spatial streams assigned during NDP transmission. As an example, the NSS information may be composed of 3 bits and can indicate any one of 1 to 8 as the number of spatial streams.

[0242] The measurement ID is information for indicating R2R measurement and may be composed of ID information. The ID indicated by the measurement ID may be set to a defined setup ID or a sensing measurement setup ID during R2R procedure setup.

[0243] The SR2SR sub - field may contain information for indicating SR2SR measurement. As an example, when the SR2SR sub - field value is set to 1, this indicates that SR2SR measurement is to be performed, and when the SR2SR sub - field value is set to 0, this indicates that SR2SR measurement is not to be performed.

[0244] The AP can send a trigger frame containing a user field for the STA participating in the SR2SR sensing measurement. At this time, non-AP STAs (e.g., non-AP STA1, non-AP STA2, ··· non-AP STA n) performing the SR2SR measurement can confirm that the SR2SR measurement is to be performed by checking the AID included in the user information field. Also, the non-AP STA can confirm the operation or / and role it will perform during the SR2SR sensing measurement from the user information field.

[0245] As an example, the user information field included in the trigger frame sent by the AP for the SR2SR sensing measurement may be configured as shown in (c) of FIG. 12.

[0246] As an example, the first user (information) field may include information about the non-AP STA (i.e., Tx STA) that transmits the NDP during the SR2SR measurement. One or more user fields following the first user field may be user fields for STAs (i.e., Rx STAs) that receive the NDP transmitted by other STAs and measure the channel.

[0247] As shown in (c) of FIG. 12, the non-AP STA that grasps the execution of the SR2SR measurement by the trigger frame sent by the AP can send and receive the NDP based on the information received by the trigger frame.

[0248] The NDP transmission / reception procedure and the subsequent procedure may be the same as in Embodiment 1. When the measurement ID is included in the trigger frame, the measurement ID information may be included in and transmitted / received by the feedback request frame and the feedback report frame. The feedback report frame may include the ID information of the receiving STA that transmits the CSI information.

[0249] In order for the STA to receive CSI information measured using the NDP received from other STAs by SR2SR measurement, the AP (i.e., the sensing initiator) can utilize the reporting procedures shown in FIGS. 13(a) and 13(b).

[0250] Specifically, the AP (i.e., the sensing initiator) can transmit a reporting sensing trigger frame to request CSI information measured by SR2SR sensing measurement from a non-AP STA (i.e., the sensing responder or SR2SR receiver STA).

[0251] The reporting sensing trigger frame transmitted by the AP may be configured identically to the reporting sensing trigger frame transmitted to request CSI feedback in sensing measurement.

[0252] The non-AP STA (i.e., the sensing responder) that has performed SR2SR sensing measurement can include the CSI information measured using the reporting sensing trigger frame received from the AP in a report frame. Then, the non-AP STA (i.e., the sensing responder) can transmit the CSI information included in the report frame using the RU or BW allocated by the TB PPDU.

[0253] To indicate CSI information for SR2SR sensing measurement to the AP, the feedback CSI information transmitted by the non-AP STA (i.e., the sensing responder) may be transmitted in a sensing report frame. At this time, the sensing report frame may include the ID information, AID, or UID (USID) of the STA.

[0254] The sensing report frame may include the ID information of the STA that transmitted the NDP (i.e., the ID of the Tx STA).

[0255] The AP (i.e., the sensing initiator) can confirm which STA - to - STA channel information the CSI received by the non - AP STA (i.e., the sensing responder) through the feedback report frame is.

[0256] The embodiments described above are those in which the components and features of the present disclosure are combined in a predetermined form. Each component or feature should be considered as optional unless specifically stated otherwise. Each component or feature may be implemented in a form that does not combine with other components or features. Also, it is 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 other embodiments, or may be replaced by corresponding components or features of other embodiments. It is obvious that claims without an explicit citation relationship in the claims can be combined to form embodiments or included as new claims by amendment after filing.

[0257] 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 - described detailed description should not be construed restrictively in any respect and should be considered as exemplary. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and any changes within the equivalent scope of the present disclosure are included in the scope of the present disclosure.

[0258] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that cause an apparatus or computer to perform operations according to the methods of various embodiments, and a non-transitory computer-readable medium on which such software or instructions are stored and executable on the apparatus or computer. Instructions available for programming a processing system to perform the features described in the present disclosure may be stored on or in a storage medium or computer-readable storage medium, and the features described in the present disclosure may be implemented using a computer program product including such a storage medium. The storage medium can 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 can 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. The memory can optionally include one or more storage devices located remotely from the processor. The memory or, alternatively, the non-volatile memory device within the memory includes a non-transitory computer-readable storage medium. The features described in the present disclosure may be stored on any one of the machine-readable media, integrated with software and / or firmware that can control the hardware of the processing system and cause the processing system to interact with other mechanisms to utilize the results according to the embodiments of the present disclosure. Such software or firmware can include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

Industrial Applicability

[0259] Although the method proposed in the present disclosure has been described mainly with an example applied to an IEEE 802.11-based system, it can 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 station (STA) in a wireless LAN system, the method comprising: receiving, from a second STA, a sensing trigger frame including a trigger-dependent common information subfield; receiving, based on the sensing trigger frame, an NDP (null data physical protocol data unit (PPDU)) from at least one STA or transmitting the NDP to the at least one STA; wherein the trigger-dependent common information subfield includes a measurement session ID field and a sensing trigger subtype field; wherein the sensing trigger subtype field includes information indicating that the subtype of the sensing trigger frame is SR2SR (sensing responder to sensing responder) sounding.

2. The method according to claim 1, wherein the measurement session ID field includes a measurement session ID corresponding to sensing measurement parameters associated with the SR2SR sounding based on the sensing trigger frame.

3. The method according to claim 1, wherein information indicating whether to assist the SR2SR sounding is transmitted to the second STA.

4. The method according to claim 1, wherein based on the role of the first STA being indicated as an SR2SR sensing transmitter by a Tx / Rx subfield included in a transmitter user information field of the sensing trigger frame, the NDP is transmitted by the first STA to the at least one STA.

5. Each of at least one receiver user information field of the sensing trigger frame includes a Tx / Rx subfield; Based on the role of the first STA being indicated as an SR2SR sensing receiver by a Tx / Rx subfield included in a specific receiver user information field corresponding to the first STA among the at least one receiver user information field, the NDP is transmitted from an SR2SR sensing transmitter among the at least one STA to the first STA.

6. The method according to claim 5, wherein a sensing measurement report frame is transmitted from the first STA to the second STA based on receiving, from the second STA, a sensing report trigger frame requesting measurement information based on the NDP. **Claim 7** The method according to claim 5, wherein the specific recipient user information field includes the ID of the first STA and the ID of the SR2SR sensing transmitter. **Claim 8** The method according to claim 6, wherein the sensing measurement report frame includes the measurement session ID field, the ID of the first STA, and CSI (channel state information) obtained based on the NDP. **Claim 9** The method according to claim 1, wherein the sensing trigger frame includes a field indicating the number of HE (high throughput)-LTF (long training field) repetitions associated with the NDP. **Claim 10** The first STA is a non-AP STA that is an SR2SR sensing transmitter or an SR2SR sensing receiver, and the second STA is an AP that is a sensing initiator, according to the method of claim 1. **Claim 11** A first station (STA) operating in a wireless LAN system, the first STA including: one or more transceivers; one or more processors coupled to the one or more transceivers, wherein the one or more processors are configured to: receive, from a second STA via the one or more transceivers, a sensing trigger frame including a trigger-dependent common information subfield; receive an NDP (null data physical protocol data unit (PPDU)) from at least one STA or transmit the NDP to the at least one STA via the one or more transceivers based on the sensing trigger frame; the trigger-dependent common information subfield includes a measurement session ID field and a sensing trigger subtype field; the sensing trigger subtype field includes information indicating that the subtype of the sensing trigger frame is SR2SR (sensing responder to sensing responder) sounding, the first STA.

12. A method performed by a second station (STA) in a wireless LAN system, the method comprising: transmitting a sensing trigger frame including a trigger-dependent common information subfield to at least one STA; transmitting a sensing report trigger frame requesting the NDP-based measurement information to a first STA among the at least one STA; receiving a sensing measurement report frame from the first STA, wherein the trigger-dependent common information subfield includes a measurement session ID field and a sensing trigger subtype field, wherein the sensing trigger subtype field includes information indicating that the subtype of the sensing trigger frame is SR2SR (sensing responder to sensing responder) sounding.

13. A second station (STA) operating in a wireless LAN system, the second STA comprising: one or more transceivers; one or more processors coupled to the one or more transceivers, wherein the one or more processors are configured to: transmit trigger information for transmission of a null data physical protocol data unit (PPUD) announcement frame to at least one STA via the one or more transceivers; transmit a sensing report trigger frame requesting the NDP-based measurement information to a first STA among the at least one STA via the one or more transceivers; receive a sensing measurement report frame from the first STA via the one or more transceivers, wherein the trigger-dependent common information subfield includes a measurement session ID field and a sensing trigger subtype field, wherein the sensing trigger subtype field includes information indicating that the subtype of the sensing trigger frame is SR2SR (sensing responder to sensing responder) sounding.

14. A processing device configured to control a first station (STA) operating in a wireless LAN system, the processing device comprising: one or more processors; one or more computer memories operably coupled to the one or more processors and storing instructions for performing operations based on execution by the one or more processors; and the operations include: receiving from a second STA a sensing trigger frame including a trigger-dependent common information subfield; based on the sensing trigger frame, receiving an NDP (null data physical protocol data unit (PPDU)) from at least one STA or transmitting the NDP to the at least one STA; the trigger-dependent common information subfield includes a measurement session ID field and a sensing trigger subtype field; the sensing trigger subtype field includes information indicating that the subtype of the sensing trigger frame is SR2SR (sensing responder to sensing responder) sounding, the processing device.

15. One or more non-transitory computer-readable media storing one or more instructions, the one or more instructions being executed by one or more processors to cause a device operating in a wireless LAN system to receive from a second STA a sensing trigger frame including a trigger-dependent common information subfield, based on the sensing trigger frame, be controlled to receive an NDP (null data physical protocol data unit (PPDU)) from at least one STA or transmit the NDP to the at least one STA, the trigger-dependent common information subfield includes a measurement session ID field and a sensing trigger subtype field. The sensing trigger subtype field is a computer-readable medium that includes information indicating that the subtype of the sensing trigger frame is SR2SR (sensing responder to sensing responder) sounding.

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