Method and apparatus for performing communication based on target wake-up time in wireless LAN system

Abstract

Disclosed are a method and an apparatus for operating in a wireless LAN system. According to an embodiment of the present disclosure, a method performed by an STA in a wireless LAN system comprises the steps of: receiving, from a first access point (AP), a first frame including a field of a first broadcast target wake time (TWT) parameter set and a field of a second broadcast TWT parameter set; and decoding the first frame in which first information related to a first restricted TWT (R-TWT) service period (SP) scheduled by the first AP and a first broadcast TWT identifier (ID) may be included in a first broadcast TWT parameter set, and second information related to a second R-TWT SP scheduled by the second AP and a second TWT ID may be included in a second broadcast TWT parameter set.

Description

TECHNICAL FIELD

[0001] The disclosure relates to communication operations in a wireless local area network (WLAN) system, and more particularly, to a method and apparatus for performing target wake time (TWT)-based communication in a next-generation wireless LAN system. BACKGROUND

[0002] New technologies for improving transmission rates, increasing bandwidth, improving reliability, reducing errors, and reducing latency have been introduced for wireless LANs (WLANs). Among the WLAN technologies, the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series standards can be referred to as Wi-Fi. For example, recently introduced technologies for WLANs 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] In order to provide a more perfect wireless communication environment, enhancement technologies for EHT (extremely high throughput) are being discussed. For example, technologies for supporting increased bandwidth, efficient utilization of multiple bands, and increased spatial streams, multi-access point (AP) coordination, and multiple-input multiple-output (MIMO) are being researched, and in particular, various technologies for supporting low latency or real-time traffic are being researched. In addition, new technologies for supporting ultra-high reliability (UHR) through improvements or extensions including EHT technologies are being discussed. SUMMARY

[0004] TECHNICAL PROBLEM

[0005] The technical problem of the disclosure is to provide a method and apparatus for performing TWT-based communication in a wireless LAN system.

[0006] The technical problem of the disclosure is to provide a method and apparatus for performing operations for R (restricted)-TWT service periods (SPs) scheduled by a neighboring AP in a multi-BSS (basic service set) environment.

[0007] The technical objects achieved by the disclosure are not limited to the above-mentioned technical objects, and those skilled in the related art will clearly understand other technical objects not described herein from the following description.

[0008] TECHNICAL SOLUTION

[0009] According to one embodiment of the disclosure, a method performed by a station (STA) in a wireless LAN system can include receiving, from a first access point (AP), a first frame including a first broadcast target wake-up time (TWT) parameter set field and a second broadcast TWT parameter set field; and decoding the first frame, and first information related to a first restricted TWT (R-TWT) service period (SP) scheduled by the first AP and a first broadcast TWT identifier (ID) can be included in the first broadcast TWT parameter set, and second information related to a second R-TWT SP scheduled by a second AP and a second TWT ID can be included in the second broadcast TWT parameter set.

[0010] According to one embodiment of the disclosure, a method performed by a first access point (AP) in a wireless LAN system can include receiving, from a second AP, second information related to a second restricted target wake-up time (R-TWT) service period (SP); and transmitting, to a first station (STA), a first beacon frame including first information related to a first R-TWT SP and the second information, and the first beacon frame can include a first broadcast TWT parameter set field and a second broadcast TWT parameter set field, the first broadcast TWT parameter set field can include the first information and a first broadcast TWT ID, and the second broadcast TWT parameter set field can include the second information and a second broadcast TWT ID.

[0011] Advantageous Effects

[0012] According to various embodiments of the disclosure, a method and an apparatus for performing TWT-based communication in a wireless LAN system can be provided.

[0013] According to various embodiments of the disclosure, a method and an apparatus for performing an operation for an R-TWT SP scheduled by a neighboring AP in a multi-BSS environment can be provided.

[0014] According to various embodiments of the disclosure, a method and an apparatus for protecting an OBSS (overlapping basic service set) R-TWT SP announced by an AP can be provided.

[0015] Effects achievable by the disclosure are not limited to the above-mentioned effects, and other effects not described herein can be clearly understood by those skilled in the art from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings, which are included as part of the detailed description and serve to understand the detailed description of the disclosure, provide embodiments of the disclosure and describe technical features of the disclosure through the detailed description.

[0017] Figure 1 A block configuration diagram of a wireless communication apparatus according to an embodiment of the disclosure is illustrated.

[0018] Figure 2 is a diagram illustrating an exemplary structure of a WLAN system to which the disclosure can be applied.

[0019] Figure 3 is a diagram for describing a link setup procedure to which the disclosure can be applied.

[0020] Figure 4 is a diagram for describing a backoff procedure to which the disclosure can be applied.

[0021] Figure 5 is a diagram for describing a CSMA / CA-based frame transmission operation to which the disclosure can be applied.

[0022] Figure 6 is a diagram for describing an example of a frame structure used in a WLAN system to which the disclosure can be applied.

[0023] Figure 7 is a diagram illustrating an example of a PPDU defined in an IEEE 802.11 standard to which the disclosure can be applied.

[0024] Figure 8 is a diagram illustrating an example of a single TWT operation to which the disclosure can be applied.

[0025] Figure 9 is a diagram illustrating an example of a broadcast TWT operation to which the disclosure can be applied.

[0026] Figure 10 is a diagram illustrating an example of a TWT information element format.

[0027] Figure 11 is a diagram illustrating an example of a single TWT parameter set field format.

[0028] Figure 12 is a diagram illustrating an example of a broadcast TWT parameter set field format.

[0029] Figure 13 is a diagram illustrating an example of a field format related to a limited TWT operation.

[0030] Figure 14 is a diagram illustrating a method for a STA to perform a listening operation in a multi-BSS environment according to an embodiment of the disclosure.

[0031] Figure 15 is a flowchart illustrating operations of a STA according to an embodiment of the disclosure.

[0032] Figure 16 is a diagram illustrating operations of a first AP according to an embodiment of the disclosure.

[0033] Figure 17 is a diagram illustrating an operation of a STA to protect an OBSS R-TWT SP according to an embodiment of the disclosure.

[0034] Figure 18 is a diagram illustrating a configuration of a field including information related to an OBSS R-TWT according to an embodiment of the disclosure.

[0035] Figure 19 is a diagram illustrating an operation of an AP to announce an OBSS R-TWT SP according to an embodiment of the disclosure.

[0036] Figure 20 is a diagram illustrating an operation of an AP to announce an overlapping quiet interval according to an embodiment of the disclosure.

[0037] Figure 21 is a diagram for describing an R-TWT SP announcement method of an AP for each STA type according to an embodiment of the disclosure.

[0038] Figure 22 is a diagram for describing a TB PPDU transmission and reception procedure between a transmitting STA and a receiving STA according to an example of the disclosure. DETAILED DESCRIPTION

[0039] Hereinafter, embodiments according to the disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed in the accompanying drawings is to describe exemplary embodiments of the disclosure and is not intended to represent the only embodiment in which the disclosure can be implemented. The following detailed description includes specific details in order to provide a thorough understanding of the present disclosure. However, it will be apparent to those skilled in the art that the present disclosure can be implemented without the specific details.

[0040] In some cases, known structures and devices can be omitted, or can be shown in the form of a block diagram based on each of the core functions in order to facilitate the prevention of obscuring the concept of the disclosure.

[0041] In the disclosure, when an element is referred to as being "connected", "combined", or "linked" to another element, it can include an indirect connection relationship between the other element and a further element existing therebetween as well as a direct connection relationship. In addition, in the disclosure, the term "including" or "having" specifies the existence of the mentioned features, steps, operations, components, and / or elements, but does not exclude the existence or addition of one or more other features, stages, operations, components, elements, and / or groups thereof.

[0042] In the present disclosure, terms such as "first", "second", and the like are used to distinguish one element from another element and do not limit the elements unless otherwise specified, and do not limit the order or importance of the elements, etc. Therefore, within the scope of the present disclosure, a first element in an embodiment can be referred to as a second element in another embodiment, and likewise, a second element in an embodiment can be referred to as a first element in another embodiment.

[0043] The terms used in the present disclosure are used to describe particular embodiments, and are not intended to limit the claims. As used in the description of the embodiments and the appended claims, the singular form is intended to include the plural forms, unless the context clearly dictates otherwise. The term "and / or" used in the present disclosure can refer to one of the relevant listed items, or mean any and all possible combinations of two or more of them. In addition, unless otherwise specified, " / " between words in the present disclosure has the same meaning as "and / or".

[0044] Examples of the present disclosure can be applied to various wireless communication systems. For example, examples of the present disclosure can be applied to a wireless LAN system. For example, examples of the present disclosure can be applied to a wireless LAN based on IEEE 802.11a / g / n / ac / ax standards. In addition, examples of the present disclosure can be applied to a wireless LAN based on a newly proposed IEEE 802.11be (or EHT) standard. Examples of the present disclosure can be applied to a wireless LAN based on an IEEE 802.11be version-2 standard corresponding to additional enhancement technologies of the IEEE 802.11be version-1 standard. In addition, examples of the present disclosure can be applied to a next-generation standard-based wireless LAN after the IEEE 802.11be. Furthermore, examples of the present disclosure can be applied to a cellular wireless communication system. For example, it can be applied to a cellular wireless communication system based on long-term evolution (LTE)-based technologies and 5G new radio (NR)-based technologies based on third generation partnership project (3GPP) standards.

[0045] Hereinafter, technical features to which examples of the present disclosure can be applied will be described.

[0046] Figure 1 A block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0047] Figure 1The first and second devices 100 and 200 illustrated in the middle can be replaced with various terms such as terminal, wireless device, wireless transmit receive unit (WTRU), user equipment (UE), mobile station (MS), user terminal (UT), mobile subscriber station (MSS), mobile subscriber unit (MSU), subscriber station (SS), advanced mobile station (AMS), wireless terminal (WT), or simply user, etc. In addition, the first and second devices 100 and 200 can include an access point (AP), a base station (BS), a fixed station, a node B, a base transceiver system (BTS), a network. It can be replaced by various terms such as an artificial intelligence (AI) system, a road side unit (RSU), a repeater, a router, a relay, and a gateway, etc.

[0048] Figure 1 The devices 100 and 200 illustrated in the middle can be referred to as stations (STAs). For example, Figure 1 The devices 100 and 200 illustrated in the middle can be referred to by various terms such as a transmitting device, a receiving device, a transmitting STA, and a receiving STA. For example, the STAs 110 and 200 can perform an access point (AP) role or a non-AP role. That is, in the present disclosure, the STAs 110 and 200 can perform the functions of the AP and / or the non-AP. When the STAs 110 and 200 perform the AP function, they can be simply referred to as an AP, and when the STAs 110 and 200 perform the non-AP function, they can be simply referred to as a STA. In addition, in the present disclosure, the AP can also be indicated as an AP STA.

[0049] Reference Figure 1 The first and second devices 100 and 200 can transmit and receive radio signals through various wireless LAN technologies (for example, IEEE 802.11 series). The first and second devices 100 and 200 can include an interface for a medium access control (MAC) layer and a physical layer (PHY) to comply with the IEEE 802.11 standard.

[0050] In addition, the first and second devices 100 and 200 can additionally support various communication standards (for example, 3GPP LTE series, 5G NR series standards, etc.) technologies other than the wireless LAN technology. In addition, the devices of the present disclosure can be implemented in various devices such as a mobile phone, a vehicle, a personal computer, an augmented reality (AR) device, a virtual reality (VR) device, etc. In addition, the STAs of the present specification can support various communication services such as voice call, video call, data communication, autonomous driving, machine type communication (MTC), machine to machine (M2M), device to device (D2D), IoT (Internet of Things), etc.

[0051] The first device 100 can include one or more processors 102 and one or more memories 104, and can additionally include one or more transceivers 106 and / or one or more antennas 108. The processor 102 can control the memory 104 and / or the transceiver 106 and can be configured to implement the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed in the present disclosure. For example, the processor 102 can generate first information / signal by processing information in the memory 104, and then transmit a wireless signal including the first information / signal through the transceiver 106. Also, the processor 102 can receive a wireless signal including second information / signal through the transceiver 106, and then store information obtained by signal processing of the second information / signal in the memory 104. The memory 104 can be connected to the processor 102 and can store a variety of information related to operations of the processor 102. For example, the memory 104 can store software code including instructions for performing all or a part of processes controlled by the processor 102 or for performing the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed in the present disclosure. Here, the processor 102 and the memory 104 can be a part of a communication modem / circuit / chip designed to implement a wireless LAN technology (e.g., LTE 802.11 series). The transceiver 106 can be connected to the processor 102 and can transmit and / or receive a wireless signal through the one or more antennas 108. The transceiver 106 can include a transmitter and / or a receiver. The transceiver 106 can be used together with an RF (Radio Frequency) unit. In the present disclosure, a device can mean a communication modem / circuit / chip.

[0052] The second device 200 can include one or more processors 202 and one or more memories 204, and can additionally include one or more transceivers 206 and / or one or more antennas 208. The processor 202 can control the memory 204 and / or the transceiver 206 and can be configured to implement the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed in the present disclosure. For example, the processor 202 can generate third information / signal by processing information in the memory 204, and then transmit a wireless signal including the third information / signal through the transceiver 206. In addition, the processor 202 can receive a wireless signal including fourth information / signal through the transceiver 206, and then store information obtained by signal processing of the fourth information / signal in the memory 204. The memory 204 can be connected to the processor 202 and can store a variety of information related to operations of the processor 202. For example, the memory 204 can store software code including instructions for performing all or part of processes controlled by the processor 202 or for performing the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed in the present disclosure. Here, the processor 202 and the memory 204 can be part of a communication modem / circuit / chip designed to implement a wireless LAN technology (e.g., IEEE 802.11 series). The transceiver 206 can be connected to the processor 202 and can transmit and / or receive a wireless signal through the one or more antennas 208. The transceiver 206 can include a transmitter and / or a receiver. The transceiver 206 can be used together with an RF unit. In the present disclosure, a device can mean a communication modem / circuit / chip.

[0053] Hereinafter, the hardware elements of the devices 100, 200 will be described in more detail. They are not limited thereto, but one or more protocol layers can be implemented by one or more processors 102, 202. For example, the one or more processors 102, 202 can implement one or more layers (e.g., functional layers such as PHY, MAC). The one or more processors 102, 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 operational flowcharts disclosed in the present disclosure. The one or more processors 102, 202 can generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure. The one or more processors 102, 202 can generate signals (e.g., baseband signals) including the PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in the present disclosure to provide them to the one or more transceivers 106, 206. The one or more processors 102, 202 can receive signals (e.g., baseband signals) from the one or more transceivers 106, 206 and obtain the PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure.

[0054] The one or more processors 102, 202 can be referred to as controllers, microcontrollers, microprocessors, or microcomputers. The one or more processors 102, 202 can be implemented by hardware, firmware, software, or a combination thereof. In 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) can be included in the one or more processors 102, 202. The descriptions, functions, procedures, proposals, methods, and / or operational flowcharts included in the present disclosure can be implemented by using firmware or software and the firmware or software can be implemented as including modules, procedures, functions, etc. The firmware or software configured to perform the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts included in the present disclosure can be included in the one or more processors 102, 202 or can be 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 operational flowcharts included in the present disclosure can be implemented in the form of codes, commands, and / or command sets by firmware or software.

[0055] One or more memories 104, 204 can be connected to one or more processors 102, 202 and can be capable of storing data, signals, messages, information, programs, codes, instructions, and / or commands in various forms. One or more memories 104, 204 can be configured with ROM, RAM, EPROM, flash memory, a hard disk drive, a register, a cache memory, a computer-readable storage medium, and / or a combination thereof. One or more memories 104, 204 can be positioned inside and / or outside one or more processors 102, 202. Also, one or more memories 104, 204 can be connected to one or more processors 102, 202 by various technologies such as a wired or wireless connection.

[0056] One or more transceivers 106, 206 can transmit user data, control information, wireless signals / channels, etc. mentioned in the methods and / or operational flowcharts, etc. of the present disclosure to one or more other devices. One or more transceivers 106, 206 can receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, processes, proposals, methods, and / or operational flowcharts, etc. included in the present disclosure from one or more other devices. For example, one or more transceivers 106, 206 can be connected to one or more processors 102, 202 and can transmit and receive wireless signals. For example, one or more processors 102, 202 can control one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other devices. Also, one or more processors 102, 202 can control one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. Also, one or more transceivers 106, 206 can be connected to one or more antennas 108, 208, and one or more transceivers 106, 206 can be configured to transmit and receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, processes, proposals, methods, and / or operational flowcharts, etc. included in the present disclosure through one or more antennas 108, 208. In the present disclosure, one or more antennas can be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports). One or more transceivers 106, 206 can convert received wireless signals / channels, etc. from RF band signals to baseband signals to process received user data, control information, wireless signals / channels, etc. by using one or more processors 102, 202. One or more transceivers 106, 206 can convert user data, control information, wireless signals / channels, etc. processed by using one or more processors 102, 202 from baseband signals to RF band signals. Accordingly, one or more transceivers 106, 206 can include (analog) oscillators and / or filters.

[0057] For example, one of STAs 100 and 200 can perform the expected operation of an AP, and the other of STAs 100 and 200 can perform the expected operation of a non-AP STA. Figure 1 Transceivers 106 and 206 can perform transmission and reception operations of signals (e.g., packet or physical layer protocol data units (PPDUs) conforming to IEEE 802.11a / b / g / n / ac / ax / be). Furthermore, in this disclosure, the operations of generating transmit / receive signals or performing data processing or calculations on transmit / receive signals in advance by various STAs can be performed by… Figure 1 Processors 102 and 202 perform the following operations: For example, examples of generating transmit / receive signals or performing data processing or calculations on transmit / receive signals in advance may include 1) determining / acquiring / configuring / calculating / decoding / encoding bit information of fields (signals (SIG), short training field (STF), long training field (LTF), data, etc.) included in the PPDU; 2) determining / configuring / acquiring time resources or frequency resources (e.g., subcarrier resources) for the fields (SIG, STF, LTF, data, etc.) included in the PPDU; 3) determining / configuring / acquiring specific sequences (e.g., pilot sequences, STF / LTF sequences, additional sequences applied to SIG) for the fields (SIG, STF, LTF, data, etc.) included in the PPDU action; 4) power control operations and / or power-saving operations applied to the STA; and 5) operations related to determining / acquiring / configuring / calculating / encoding the ACK signal. Additionally, in the following examples, various information used by various STAs to determine / acquire / configure / calculate / decode / encode transmitted and received signals (e.g., information related to fields / subfields / control fields / parameters / power, etc.) can be stored. Figure 1 In memory 104 and 204.

[0058] In the following text, downlink (DL) can refer to a link used for communication from an AP STA to a non-AP STA, and DL PPDUs / packets / signals can be sent and received via DL. In DL communication, the transmitter can be part of an AP STA, and the receiver can be part of a non-AP STA. Uplink (UL) can refer to a link used for communication from a non-AP STA to an AP STA, and UL PPDUs / packets / signals can be sent and received via UL. In UL communication, the transmitter can be part of a non-AP STA, and the receiver can be part of an AP STA.

[0059] Figure 2 This is a diagram illustrating an exemplary structure of a wireless LAN system to which this disclosure can be applied.

[0060] The structure of a wireless LAN system can be composed of a plurality of components. A wireless LAN that supports mobility of STAs transparent to the upper layer can be provided through the interaction of a plurality of components. A basic service set (BSS) corresponds to a basic building block of a wireless LAN. Figure 2 Exemplarily, it is shown that there are two BSSs (BSS1 and BSS2) 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). Figure 2 The ellipse indicating the BSS in can also be understood to indicate a coverage area in which the STAs included in the corresponding BSS maintain communication. This area can be referred to as a basic service area (BSA). When a STA moves out of the BSA, it cannot directly communicate with other STAs within the BSA.

[0061] If the DS shown in is not considered, Figure 2 The most basic type of BSS in a wireless LAN is an independent BSS (IBSS) if the DS shown in is not considered. For example, an IBSS can have a minimum form including only two STAs. For example, assuming that other components are omitted, BSS1 including only STA1 and STA2 or BSS2 including only STA3 and STA4 can correspond to representative examples of an IBSS, respectively. Such a configuration is possible when STAs can directly communicate without an AP. In addition, in this type of wireless LAN, it is not configured in advance, but can be configured when a LAN is needed, and this can be referred to as an ad hoc network. Because an IBSS does not include an AP, there is no centralized management entity. That is, in an IBSS, STAs are managed in a distributed manner. In an IBSS, all STAs can consist of mobile STAs, and access to a distributed system (DS) is not allowed, thereby forming a self-contained network.

[0062] The membership of a STA in a BSS can be dynamically changed by turning the STA on or off, entering or exiting the BSS area, etc. To become a member of a BSS, a STA can join the BSS using a synchronization procedure. To access all services of the BSS infrastructure, a STA should be associated with the BSS. This association can be dynamically established and can include the use of distributed system services (DSS).

[0063] The direct STA-to-STA distance in a wireless LAN can be limited by the PHY performance. In some cases, such a distance limitation can be sufficient, but in some cases, communication between STAs at a farther distance can be required. A distributed system (DS) can be configured to support an extended coverage range.

[0064] The DS means a structure in which BSSs are interconnected. Specifically, as Figure 2As shown in FIG. 1, a BSS can exist as an extended form of a network composed of a plurality of BSSs. The DS is a logical concept and can be specified by the characteristics of a distributed system medium (DSM). In this regard, the wireless medium (WM) and the DSM can be logically separated. Each logical medium is used for different purposes and used by different components. The media are not limited to being the same nor to being different. As such, the flexibility of the wireless LAN structure (DS structure or other network structure) can be interpreted in that a plurality of media are logically different. That is, the wireless LAN structure can be implemented in various ways, and the corresponding wireless LAN structure can be independently specified by the physical characteristics of each embodiment.

[0065] The DS can support mobile devices by providing seamless integration of a plurality of BSSs and providing logical services necessary to address addresses to destinations. In addition, the DS can further include a component called a portal, which serves as a bridge for connection between the wireless LAN and other networks (for example, IEEE 802.X).

[0066] The AP enables access to the DS through the WM for the associated non-AP STA and means an entity that also has the functionality of a STA. Data movement between the BSS and the DS can be performed through the AP. For example, Figure 2 The STAs 2 and 3 shown in FIG. 1 have the functionality of a STA and provide a function that allows the associated non-AP STAs (STAs 1 and 4) to access the DS. In addition, because all APs basically correspond to STAs, all APs are addressable entities. The address used by the AP for communication on the WM and the address used by the AP for communication on the DSM are not necessarily the same. A BSS composed of an AP and one or more STAs can be referred to as an infrastructure BSS.

[0067] Data transmitted from one of the STAs associated with the AP to the STA address of the corresponding AP can always be received on an uncontrolled port and can be processed by an IEEE 802.1X port access entity. In addition, when the controlled port is authenticated, the transmission data (or frame) can be delivered to the DS.

[0068] In addition to the structure of the DS described above, an extended service set (ESS) can be configured to provide extensive coverage.

[0069] The ESS means a network in which networks of arbitrary size and complexity are composed of DSs and BSSs. The ESS can correspond to a set of BSSs connected to one DS. However, the ESS does not include the DS. The ESS network is characterized in that it is regarded as an IBSS in the logical link control (LLC) layer. The STAs included in the ESS can communicate with each other, and a mobile STA can move from one BSS to another BSS (within the same ESS) transparently to the LLC. The APs included in one ESS can have the same service set identification (SSID). The SSID is distinguished from the BSSID, which is an identifier of the BSS.

[0070] The wireless LAN system does not assume anything about the relative physical locations of the BSSs, and all of the following forms are possible. The BSSs can partially overlap, which is a form commonly used to provide continuous coverage. In addition, the BSSs can not be physically connected, and logically, there is no limit to the distance between the BSSs. In addition, the BSSs can be physically located in the same place, which can be used to provide redundancy. In addition, one (or more) IBSS or ESS network can physically exist in the same space as one (or more than one) ESS network. This can be similar to the form corresponding to the ESS network when an ad hoc network operates in a location in which an ESS network exists, when physically overlapping wireless networks are configured by different organizations, or when two or more different access and security policies are required in the same location.

[0071] Figure 3 is a diagram for explaining a link setup procedure to which the present disclosure can be applied.

[0072] In order for the STA to set up a link with respect to the network and transmit / receive data, the network is first discovered, authentication is performed, association is established, and an authentication procedure for security needs to be performed. The link setup procedure can also be referred to as a session initiation procedure or a session setup procedure. In addition, the procedures of discovery, authentication, association, and security setup of the link setup procedure can be collectively referred to as an association procedure.

[0073] In step S310, the STA can perform a network discovery operation. The network discovery operation can include a scanning operation of the STA. That is, in order for the STA to access the network, it needs to find a network that can participate. The STA should identify a compatible network before participating in a wireless network, and the process of identifying a network present in a specific area is referred to as scanning.

[0074] The scanning scheme includes active scanning and passive scanning. Figure 3A network discovery operation including an active scanning procedure is exemplarily illustrated. In the active scanning, the STA performing the scanning transmits a probe request frame while moving through the channels to discover what APs exist around it and waits for a response to this. The responder transmits a probe response frame to the STA having transmitted the probe request frame as a response to the probe request frame. Here, the responder can be the STA which last transmitted a beacon frame in the BSS being scanned. In the BSS, since the AP transmits the beacon frame, the AP becomes the responder, and in the IBSS, the STAs in the IBSS take turns transmitting the beacon frame, so the responder is not constant. For example, the STA which transmits the probe request frame on channel 1 and receives the probe response frame on channel 1 can store the BSS-related information included in the received probe response frame, and can move to the next channel (e.g., channel 2) and perform the scanning in the same manner (i.e., transmission / reception of probe request / response on channel 2).

[0075] Although Figure 3 The scanning operation can be performed in a passive scanning manner, although not illustrated in FIG. 3. In the passive scanning, the STA performing the scanning waits for a beacon frame while moving through the channels. The beacon frame is one of the management frames defined in IEEE 802.11, and is periodically transmitted to notify the existence of the wireless network and allow the STA performing the scanning to find the wireless network and participate in the wireless network. In the BSS, the AP serves as the beacon frame periodically transmitted, and in the IBSS, the STAs within the IBSS take turns transmitting the beacon frame. When the STA performing the scanning receives the beacon frame, the STA stores the information for the BSS included in the beacon frame and records the beacon frame information in each channel while moving to another channel. The STA receiving the beacon frame can store the BSS-related information included in the received beacon frame, move to the next channel, and perform the scanning in the next channel in the same manner. Comparing the active scanning and the passive scanning, the active scanning has the advantage of less latency and lower power consumption than the passive scanning.

[0076] After the STA discovers the network, an authentication procedure can be performed in step S320. In order to explicitly distinguish from the security setup operation of step S340 which will be described later, this authentication procedure can be referred to as a first authentication procedure.

[0077] The authentication procedure includes a procedure in which the STA transmits an authentication request frame to the AP, and in response to this, the AP transmits an authentication response frame to the STA. The authentication frame for authentication request / response corresponds to a management frame.

[0078] The authentication frame includes an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a robust security network (RSN), and a finite cyclic group, etc. This corresponds to some examples of information that can be included in the authentication request / response frame, and can be replaced with other information or can further include additional information.

[0079] The STA can transmit an authentication request frame to the AP. The AP can determine whether to allow authentication of the corresponding STA based on information included in the received authentication request frame. The AP can provide a result of the authentication procedure to the STA through an authentication response frame.

[0080] After the STA is successfully authenticated, an association procedure can be performed in step S330. The association procedure includes a procedure in which the STA transmits an association request frame to the AP, and in response, the AP transmits an association response frame to the STA.

[0081] For example, the association request frame can include information related to various capabilities, a beacon listen interval, a service set identifier (SSID), supported rates, supported channels, an RSN, a mobility domain, supported operating classes, a traffic indication map broadcast request (TIM broadcast request), interworking service capabilities, etc. For example, the association response frame can include information related to various capabilities, a status code, an association ID (AID), supported rates, an enhanced distributed channel access (EDCA) parameter set, a received channel power indicator (RCPI), a received signal to noise indicator (RSNI), a mobility domain, a super interval (e.g., an association recovery time), an overlapping BSS scan parameter, a TIM broadcast response, a quality of service (QoS) map, etc. This corresponds to some examples of information that can be included in the association request / response frame, and can be replaced with other information or can further include additional information.

[0082] After the STA is successfully associated with the network, a security setup procedure can be performed in step S340. The security setup procedure of step S340 can be referred to as an authentication procedure through a robust security network association (RSNA) request / response, and the authentication procedure of step S320 is referred to as a first authentication procedure, and the security setup procedure of step S340 can also be simply referred to as an authentication procedure.

[0083] The security setup procedure of step S340 can include a procedure of setting up a private key, for example, through a 4-way handshake of an extensible authentication protocol over LAN (EAPOL) frame. In addition, the security setup procedure can be performed according to a security scheme that is not defined in the IEEE 802.11 standard.

[0084] Figure 4 is a diagram for explaining a backoff procedure to which the present disclosure can be applied.

[0085] In a wireless LAN system, a basic access mechanism of a medium access control (MAC) is a carrier sense multiple access with collision avoidance (CSMA / CA) mechanism. The CSMA / CA mechanism is also called a distributed coordination function (DCF) of IEEE 802.11 MAC, and basically adopts a "listen before talk" access mechanism. According to this type of access mechanism, an AP and / or a STA can perform a clear channel assessment (CCA) of sensing a wireless channel or medium for a predetermined time interval (e.g., a DCF interframe space (DIFS)) before starting a transmission. As a result of the sensing, if it is determined that the medium is in an idle state, a frame transmission is started through the corresponding medium. On the other hand, if it is detected that the medium is occupied or busy, the corresponding AP and / or STA does not start its own transmission, and can set a delay period (e.g., a random backoff period) for medium intervention and attempt a frame transmission after waiting. By applying the random backoff period, since a number of STAs are expected to attempt a frame transmission after waiting for different time periods, a collision can be minimized.

[0086] In addition, the IEEE 802.11 MAC protocol provides a hybrid coordination function (HCF). The HCF is based on the DCF and a point coordination function (PCF). The PCF is a synchronous access method based on polling, and refers to a method in which all receiving APs and / or STAs are periodically polled to receive data frames. In addition, the HCF has an enhanced distributed channel access (EDCA) and a HCF-controlled channel access (HCCA). The EDCA is a contention-based access method for providing data frames from a provider to a plurality of users, and the HCCA uses a polling mechanism using a non-contention-based channel access method. In addition, the HCF includes a medium access mechanism for improving QoS (quality of service) of a wireless LAN, and can transmit QoS data in both a contention period (CP) and a contention free period (CFP).

[0087] Reference Figure 4This section describes the operation based on a random backoff period. When a occupied / busy medium becomes idle, several STAs may attempt to transmit data (or frames). As a method to minimize collisions, each STA can individually select a random backoff count and attempt transmission after waiting for the corresponding time slot. The random backoff count has a pseudo-random integer value and can be determined as one of the values ​​from 0 to CW. Here, CW is the contention window parameter value. The CW parameter is assigned an initial value of CWmin, but can be doubled if a transmission failure occurs (e.g., when an ACK for a transmitted frame is not received). When the CW parameter value reaches CWmax, data transmission can be attempted while maintaining the CWmax value until successful data transmission, and the CWmin value is reset when data transmission is successful. The values ​​of CW, CWmin, and CWmax are preferably set to 2. n -1 (n = 0, 1, 2, ...).

[0088] When the random backoff process begins, the STA continuously monitors the medium while counting down the backoff time slot based on the determined backoff count value. When medium occupancy is detected, it stops counting down and waits, and resumes the remaining countdown when the medium becomes free.

[0089] exist Figure 4 In the example, when the packet to be sent arrives at STA3's MAC, STA3 can send the frame immediately after confirming that the medium is free for as long as DIFS. The remaining STAs monitor and wait for the medium to be occupied / busy. Meanwhile, data to be sent may also occur in each of STA1, STA2, and STA5, and when the medium is detected as free, each STA waits for as long as DIFS, and can then count down the backoff slots according to a random backoff count value selected by each STA. Assume that STA2 chooses the minimum backoff count value, and STA1 chooses the maximum backoff count value. That is, the case where STA5's remaining backoff time is less than STA1's remaining backoff time when STA2 completes its backoff count and begins frame transmission is illustrated. STA1 and STA5 temporarily stop the countdown and wait, while STA2 occupies the medium. When STA2 finishes occupying the medium and it becomes free again, STA1 and STA5 wait for DIFS and resume the stopped backoff count. That is, after counting down the remaining backoff slots for the remaining backoff time, frame transmission can begin. Because STA5's remaining backoff time is less than STA1's, STA5 begins frame transmission. While STA2 is occupying the medium, data to be transmitted may also appear in STA4. From STA4's perspective, when the medium becomes idle, STA4 can wait for DIFS, and then execute a countdown based on a random backoff count value selected by STA4 and begin transmitting frames. Figure 4The example illustrates a scenario where the remaining backoff time of STA5 coincides exactly with the random backoff count of STA4. In this case, a collision may occur between STA4 and STA5. When a collision occurs, neither STA4 nor STA5 receives an ACK, thus data transmission fails. In this situation, STA4 and STA5 can double their CW value, choose a random backoff count, and begin a countdown. STA1 waits while the medium is occupied due to the transmissions of STA4 and STA5, waits for DIFS when the medium becomes idle, and then begins frame transmission after the remaining backoff time has elapsed.

[0090] like Figure 4 As shown in the example, data frames are frames used to transmit data forwarded to higher layers and can be sent after a backoff following the elapsed DIFS when the medium becomes idle. Management frames are frames used to exchange management information that is not forwarded to higher layers and are sent after a backoff following an IFS such as a DIFS or a Point Coordination Function IFS (PIFS). Subtypes of management frames include beacons, association requests / responses, reassociation requests / responses, probe requests / responses, authentication requests / responses, etc. Control frames are frames used to control access to the medium. Subtypes of control frames include request to send (RTS), clear send (CTS), acknowledgment (ACK), power-saving polling (PS-Poll), block ACK (BlockAck), block ACK request (BlockACKReq), empty data packet advertisement (NDP advertisement), and triggers, etc. If a control frame is not a response frame to a previous frame, it is sent after a backoff following the elapsed DIFS; if it is a response frame to a previous frame, it is sent without a backoff following the elapsed short IFS (SIFS). The type and subtype of a frame can be identified by the type field and subtype field in the Frame Control (FC) field.

[0091] The Quality of Service (QoS) ST can perform a backoff following the Arbitration IFS (AIFS) of the Access Class (AC) to which the frame belongs, i.e., AIFS[i] (where i is a value determined by the AC), and then the frame can be sent. Here, frames that can use AIFS[i] can be data frames, management frames, or control frames other than response frames.

[0092] Figure 5 This is a diagram used to explain the CSMA / CA-based frame transmission operation to which this disclosure can be applied.

[0093] As mentioned above, the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing, which is directly sensed by the STA. Virtual carrier sensing is designed to compensate for problems that may arise in media access, such as hidden node issues. For virtual carrier sensing, the STA's MAC can use a Network Allocation Vector (NAV). The NAV is a value that indicates to other STAs the remaining time until the media becomes available for use by the currently used or authorized STA. Therefore, a value set to NAV corresponds to a period of time during which the media is scheduled for use by the STA sending the frame, and the STA receiving the NAV value is prohibited from accessing the media during the corresponding period. For example, the NAV can be configured based on the value of the "Duration" field in the MAC header of the frame.

[0094] exist Figure 5 In the example, it is assumed that STA1 intends to send data to STA2, and STA3 is in a position that can listen to some or all of the frames sent and received between STA1 and STA2.

[0095] To reduce the likelihood of transmission conflicts between multiple STAs in CSMA / CA-based frame transmission operations, a mechanism using RTS / CTS frames can be applied. Figure 5 In the example, while STA1 is transmitting, as a result of STA3's carrier sensing, it can be determined that the medium is in an idle state. That is, STA1 can correspond to a hidden node of STA3. Alternatively, in Figure 5 In the example, it can be determined that the carrier sensing result medium of STA3 is idle while the transmission of STA2 is being performed. That is, STA2 can correspond to a hidden node of STA3. By exchanging RTS / CTS frames before data transmission and reception between STA1 and STA2, STAs outside the transmission range of either STA1 or STA2, or STAs outside the carrier sensing range for transmissions from STA1 or STA3, can not attempt to occupy the channel during data transmission and reception between STA1 and STA2.

[0096] Specifically, STA1 can determine whether a channel is in use through carrier sensing. Regarding physical carrier sensing, STA1 can determine the channel occupancy status based on the energy level or signal correlation detected in the channel. Furthermore, regarding virtual carrier sensing, STA1 can use a network allocation vector (NAV) timer to determine the channel occupancy status.

[0097] When the channel is idle during DIFS, STA1 can send an RTS frame to STA2 after performing backoff. When STA2 receives the RTS frame, STA2 can send a CTS frame to STA1 after SIFS as a response to the RTS frame.

[0098] If STA3 cannot listen to CTS frames from STA2 but can listen to RTS frames from STA1, STA3 can use the duration information included in the RTS frame to set the NAV timer for subsequent consecutive frame transmission periods (e.g., SIFS+CTS frame+SIFS+data frame+SIFS+ACK frame). Alternatively, if STA3 can listen to CTS frames from STA2, even if STA3 cannot listen to RTS frames from STA1, STA3 can use the duration information included in the CTS frame to set the NAV timer for subsequent consecutive frame transmission periods (e.g., SIFS+data frame+SIFS+ACK frame). That is, if STA3 can listen to one or more RTS or CTS frames from STA1 or STA2, STA3 can set the NAV accordingly. When STA3 receives a new frame before the NAV timer expires, STA3 can update the NAV timer using the duration information included in the new frame. STA3 does not attempt channel access before the NAV timer expires.

[0099] When STA1 receives a CTS frame from STA2, STA1 can send a data frame to STA2 after the SIFS period starting from the time when the CTS frame reception is completed. When STA2 successfully receives the data frame, STA2 can send an ACK frame to STA1 as a response to the data frame after the SIFS period. When the NAV timer expires, STA3 can determine whether the channel is being used through carrier sensing. When STA3 determines that the channel is not being used by other terminals during the DIFS period after the NAV timer expires, STA3 can attempt channel access after the contention window (CW) for random backoff has elapsed.

[0100] Figure 6 This is a diagram used to explain an example of the frame structure that can be used in a WLAN system to which this disclosure can be applied.

[0101] Using instructions or primitives (meaning a set of instructions or parameters) from the MAC layer, the PHY layer can prepare a MAC PDU (MPDU) to be sent. For example, when it receives a command from the MAC layer requesting the PHY layer to begin transmission, the PHY layer switches to transport mode and configures the information (e.g., data) provided from the MAC layer in the form of a frame and sends it. Additionally, when the PHY layer detects a valid preamble to a received frame, it monitors the preamble header and sends a command to the MAC layer notifying the PHY layer of the start of reception.

[0102] In this way, information transmission / reception in a wireless LAN system is performed in the form of frames, and for this purpose, the PHY layer Protocol Data Unit (PPDU) frame format is defined.

[0103] A basic PPDU frame can include a Short Training Field (STF), a Long Training Field (LTF), a Signal (SIG) field, and a Data field. The most basic PPDU format (e.g., Figure 7 The non-HT (high throughput) fields shown may consist only of legacy STF (L-STF), legacy LTF (L-LTF), legacy SIG (L-SIG) fields, and a data field. Additionally, depending on the PPDU format type (e.g., HT mixed format PPDU, HT-greenfield format PPDU, VHT (very high throughput) PPDU, etc.), additional (or different 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.

[0104] STF is a signal used for signal detection, automatic gain control (AGC), diversity selection, precise time synchronization, etc., while LTF is a signal used for channel estimation and frequency error estimation. STF and LTF can be referred to as signals used for synchronization and channel estimation in the OFDM physical layer.

[0105] The SIG field can include various information related to PPDU transmission and reception. For example, the L-SIG field consists of 24 bits and can 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 can include information about the modulation and coding rate of the data. For example, the 12-bit length field can include information about the length or duration of the PPDU. For example, the value of the 12-bit length field can be determined based on the type of PPDU. For example, for non-HT, HT, VHT, or EHT PPDUs, the value of the length field can be determined to be a multiple of 3. For example, for HE PPDUs, the value of the length field can be determined to be a multiple of 3 + 1 or 3 + 2.

[0106] The data field may include the SERVICE field, Physical Layer Service Data Unit (PSDU), and PPDU tail bits, and may also include padding bits if necessary. Some bits of the SERVICE field can be used for synchronization of the descrambler at the receiver. The PSDU corresponds to the MAC PDU defined in the MAC layer and may include data generated / used in the upper layer. The PPDU tail bits can be used to return the encoder to a 0 state. Padding bits can be used to adjust the length of the data field in predetermined units.

[0107] MAC PDUs are defined according to various MAC frame formats, and a basic MAC frame consists of a MAC header, a frame body, and a Frame Check Sequence (FCS). MAC frames can be composed of MAC PDUs and are transmitted / received via the PSDU in the data portion of the PPDU frame format.

[0108] The MAC header includes a frame control field, a duration / ID field, and an address field. The frame control field can include control information required for frame transmission / reception. The duration / ID field can be set to the time for transmitting the corresponding frame. For detailed information on the sequence control, QoS control, and HT control subfields of the MAC header, please refer to the IEEE 802.11 standard document.

[0109] The NDP (Narrow Data PPDU) format refers to a PPDU format that does not include the data field. In other words, NDP refers to a frame format that includes the PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields and additional non-legacy SIG, non-legacy STF, and non-legacy LTF (if present)) but does not include the remaining portion (i.e., the data field) in the general PPDU frame format.

[0110] Figure 7 This is a diagram illustrating an example of a PPDU as defined in the IEEE 802.11 standard that can be applied to this disclosure.

[0111] Various types of PPDUs are used in standards such as IEEE 802.11a / g / n / ac / ax. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and a data field. The basic PPDU format can also be referred to as a non-HT PPDU format (e.g., ...). Figure 7 (as shown in (a)).

[0112] In addition to the basic PPDU format, the HT PPDU format (IEEE 802.11n) also includes the HT-SIG, HT-STF and HT-LFT fields. Figure 7The HT PPDU format shown in (b) can be called the HT-mixed format. Alternatively, an HT-greenfield format PPDU can be defined, which corresponds to a format consisting of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs and a data field, excluding L-STF, L-LTF and L-SIG (not shown).

[0113] Examples of VHT PPDU format (IEEE 802.11ac) include, in addition to the basic PPDU format, VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields (such as...). Figure 7 (as shown in (c)).

[0114] Examples of HE PPDU format (IEEE 802.11ax) include, in addition to the basic PPDU format, repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), and packet extension (PE) fields (such as...). Figure 7 (as shown in (d)). Based on the detailed example of the HE PPDU format, some fields may be excluded or their lengths may vary. For example, the HE-SIG-B field is included in the HE PPDU format for multi-user (MU) applications, but not in the HE PPDU format for single-user (SU) applications. Additionally, the HE trigger (TB) based PPDU format does not include HE-SIG-B, and the length of the HE-STF field may vary to 8µs. The extended range (HE ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may vary to 16µs. For example, RL-SIG can be configured to be the same as L-SIG. The receiving STA can determine whether the received PPDU is an HE PPDU or an EHT PPDU based on the presence of RL-SIG, which will be described later.

[0115] EHT PPDU format can include Figure 7 (e) EHT MU (Multi-user) and Figure 7 (f) EHT TB (trigger-based) PPDU. The EHT PPDU format is similar to the HE PPDU format in that it includes RL-SIG, followed by L-SIG, but may include U (generic)-SIG, EHT-SIG, EHT-STF and EHT-LTF following RL-SIG.

[0116] Figure 7In (e), the EHT MU PPDU corresponds to a PPDU that carries one or more data (or PSDU) for one or more users. That is, the EHT MU PPDU can be used for both SU and MU transmissions. For example, the EHT MU PPDU can correspond to a PPDU used for one or more receiving STAs.

[0117] Compared to EHT MU PPDU, Figure 7 In (f), the EHT-SIG is omitted from the EHT TB PPDU. A STA that receives a trigger (e.g., a trigger frame or trigger response schedule (TRS)) for UL MU transmission can perform UL transmission based on the EHT TB PPDU format.

[0118] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (General Signal), and EHT-SIG fields can be encoded and modulated so that even legacy STAs can attempt demodulation and decoding, and can be mapped based on a determined 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 can be encoded and modulated for demodulation and decoding 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 fields, and can be mapped based on a determined subcarrier frequency interval (e.g., 78.125 kHz). These can be referred to as EHT modulated fields.

[0119] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields can be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, Data, and PE fields can be referred to as HE modulation fields. Additionally, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be referred to as free VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields can be referred to as VHT modulation fields.

[0120] Figure 7The U-SIG included in the EHT PPDU format can be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol used for the U-SIG (e.g., an OFDM symbol) can have a duration of 4 µs, and the U-SIG can have a total duration of 8 µs. Each symbol of the U-SIG can be used to transmit 26 bits of information. For example, each symbol of the U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0121] U-SIGs can be constructed in 20MHz units. For example, if an 80MHz PPDU is constructed, the U-SIGs may be repeated. That is, an 80MHz PPDU can include the same four U-SIGs. PPDUs with bandwidths exceeding 80MHz can include different U-SIGs.

[0122] For example, A uncoded bits can be sent via U-SIG. The first symbol of U-SIG (e.g., U-SIG-1 symbol) can send the first X bits of the total A bits of information, and the second symbol of U-SIG (e.g., U-SIG-2 symbol) can send the remaining Y bits of the total A bits of information. The A bits of information (e.g., 52 uncoded bits) can include a CRC field (e.g., a 4-bit field) and a tail field (e.g., a 6-bit field). For example, the tail field can be used to terminate the grid of the convolutional decoder and can be set to 0.

[0123] The bit information sent by U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG can be included in... Figure 7 In the new PPDU format (e.g., UHR PPDU format) not shown in the figure, and 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-related bits may be different.

[0124] For example, the size of the version-independent bits in U-SIG can be fixed or variable. Version-independent bits can be assigned only to the U-SIG-1 symbol, or to both the U-SIG-1 and U-SIG-2 symbols. Version-independent bits and version-dependent bits can be referred to by various names, such as first control bits and second control bits.

[0125] For example, the version-independent bits of U-SIG may include a 3-bit Physical Layer Version Identifier (PHY Version Identifier), and this information can indicate the PHY version (e.g., EHT, UHR, etc.) of the transmitted / received PPDU. 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 about the length of the Transmission Opportunity (TXOP) and information about the BSS color ID.

[0126] For example, the version-related bits of U-SIG may include information that directly or indirectly indicates the type of PPDU (e.g., SUPPDU, MU PPDU, TB PPDU, etc.).

[0127] The information necessary for PPDU transmission and reception can be included in the U-SIG. For example, the U-SIG may further include information about the bandwidth, information about the MCS technique applied to the non-legacy SIG (e.g., EHT-SIG or UHR-SIG), information indicating whether a DCM (dual-carrier modulation) technique (e.g., a technique that achieves a frequency diversity-like effect by repeating the same signal on two subcarriers) is applied to the non-legacy SIG, information about the number of symbols used for the non-legacy SIG, and may also include information about whether the non-legacy SIG is generated across the entire band, etc.

[0128] Some information necessary for PPDU transmission and reception can be included in the U-SIG and / or non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.). For example, information about the type of non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information about the length of the non-legacy LTF and the CP (cyclic prefix) length, information about the GI (guard interval) applicable to the non-legacy LTF, information about the preamble perforation applicable to the PPDU, information about RU (resource unit) allocation, etc., can be included only in the U-SIG, only in the non-legacy SIG, or indicated by a combination of information included in the U-SIG and information included in the non-legacy SIG.

[0129] A preamble can refer to the transmission of a PPDU in which no signal is present in one or more frequency units within the bandwidth of the PPDU. For example, the size of the frequency unit (or the resolution of the preamble) can be defined as 20MHz, 40MHz, etc. For example, a preamble can be applied to a PPDU of a predetermined size or larger bandwidth.

[0130] existFigure 7 In the examples, non-legacy SIGs such as HE-SIG-B and EHT-SIG can include control information for receiving STAs. Non-legacy SIGs can be transmitted on at least one symbol, and a symbol can have a length of 4 µs. Information regarding the number of symbols used for EHT-SIGs can be included in previous SIGs (e.g., HE-SIG-A, U-SIG, etc.).

[0131] Non-legacy SIGs such as HE-SIG-B and EHT-SIG can include public fields and user-specific fields. Public fields and user-specific fields can be encoded separately.

[0132] In some cases, the common field can be omitted. For example, in compressed mode using non-OFDMA (Orthogonal Frequency Multiple Access), the common field can be omitted, and multiple STAs can receive PPDUs (e.g., the data field of the PPDU) through the same frequency band. In uncompressed mode using OFDMA, multiple users can receive PPDUs (e.g., the data field of the PPDU) through different frequency bands.

[0133] The number of user-specific fields can be determined based on the number of users. A user block field can include up to two user fields. Each user field can be associated with a MU-MIMO allocation or with a non-MU-MIMO allocation.

[0134] The common fields may include CRC bits and tail bits, where the length of the CRC bits can be determined to be 4 bits, and the length of the tail bits can be determined to be 6 bits and set to 000000. The common fields may include RU allocation information. RU allocation information may include information about the locations of RUs assigned to multiple users (i.e., multiple receiving STAs).

[0135] An RU can include multiple subcarriers (or tones). RUs can be used when transmitting signals to multiple STAs based on OFDMA technology. Additionally, RUs can be defined even when transmitting signals to a single STA. Resources can be allocated in units of RUs for non-legacy STFs, non-legacy LTFs, and data fields.

[0136] The appropriate RU size can be defined based on the PPDU bandwidth. For the applied PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.), the RUs can be defined the same or different. For example, in the case of an 80MHz PPDU, the RU placement for HEPPDU and EHT PPDU may differ. The applicable RU size, number and location, DC (direct current) subcarrier location and number, empty subcarrier location and number, guard subcarrier location and number, etc., for each PPDU bandwidth can be referred to as the tone scheme. For example, a tone scheme for high bandwidth can be defined as multiple iterations of a low bandwidth tone scheme.

[0137] RUs of various sizes can be defined as 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs, 996-tone RUs, 2×996-tone RUs, 3×996-tone RUs, etc. An MRU (multiple RUs) is distinguished from multiple individual RUs and corresponds to a group of subcarriers composed of multiple RUs. For example, an MRU can be defined as 52+26 tones, 106+26 tones, 484+242 tones, 996+484 tones, 996+484+242 tones, 2×996+484 tones, 3×996 tones, or 3×996+484 tones. Furthermore, the multiple RUs constituting an MRU can be continuous or non-contiguous in the frequency domain.

[0138] The specific size of an RU can be reduced or increased. Therefore, the specific size of each RU (i.e., the number of corresponding tones) in this disclosure is not limiting and is illustrative. In addition, in this disclosure, the number of RUs can vary depending on the RU size within a predetermined bandwidth (e.g., 20, 40, 80, 160, 320 MHz, ...).

[0139] Figure 7 The names of each field in the PPDU format are exemplary, and the scope of this disclosure is not limited to the names. Furthermore, the examples in this disclosure can be applied to... Figure 7 The PPDU format illustrated in the figure, and its application in... Target Wake Time (TWT) The PPDU format excludes some fields and / or adds some fields to the new PPDU format.

[0140] Figure 8

[0141] TWT is a power saving (PS) technology that can improve the energy efficiency of non-AP STAs by defining service periods (SPs) between APs and non-AP STAs and sharing information about SPs to reduce media contention.

[0142] The STA that executes requests / suggestions / requirements during the TWT establishment phase can be called a TWT request STA. Additionally, the AP that responds to requests (such as accept / reject) can be called a TWT response STA.

[0143] The setup process may include determining / defining the TWT request for the STA of the AP, the type of TWT operation to be performed, and the types of frames to be sent and received. TWT operations can be divided into individual TWTs and broadcast TWTs.

[0144] Figure 8 This is a diagram used to illustrate examples of individual TWT operations that can be applied to this disclosure.

[0145] A standalone TWT is a mechanism by which an AP and a non-AP STA negotiate the wake-up / sleep state of a non-AP STA and then exchange data by sending or receiving TWT request / response frames.

[0146] exist Figure 9 In the example, AP and STA 1 can form a TWT agreement that triggers the enablement through TWT request frames and TWT response frames.

[0147] Here, STA 1 uses a requested TWT method. When STA 1 sends a TWT request frame to the AP, STA 1 receives information for the TWT operation from the AP via a TWT response frame.

[0148] On the other hand, STA 2, which executes the unsolicited TWT method, can receive information from AP about the TWT convention configuration that triggers the activation through the unsolicited TWT response.

[0149] Specifically, STA 2 can calculate the next TWT by adding a specific number to the current TWT value. During the triggered TWT SP, the AP can send a trigger frame to the STA. The trigger frame can notify the STA that the AP has buffered data. In response, STA 1 can notify the AP of its wake-up status by sending a PS polling frame. Additionally, STA 2 can notify the AP of its wake-up status by sending a QoS empty frame. Here, the data frames sent by STA 1 and STA 2 can be frames in TB PPDU format. The AP, having confirmed the status of STA 1 and STA 2, can send a DL MU PPDU to wake up the STA. When the corresponding TWT SP expires, STA 1 and STA 2 can switch to sleep mode.

[0150] Figure 9 This is a diagram used to illustrate an example of the broadcast TWT operation that can be applied to this disclosure.

[0151] Broadcast TWT is a type of TWT in which a non-AP STA (or a TWT-scheduled STA) obtains information about the Target Beacon Transmission Time (TBTT) and listening interval by using an AP (or a TWT-scheduled STA) to send and receive TWT request / response frames. Here, a negotiation operation for the TBTT can be performed. Based on this, the AP can define frames that will contain the scheduling information for the TWT via beacon frames.

[0152] exist Figure 10 In this process, STA 1 performs a requested TWT operation, and STA 2 performs an unrequested TWT operation. The AP can send a DL MU PPDU after checking the wake-up status of the STA via a trigger sent by the AP. This can be the same procedure as for individual TWTs. In broadcast TWTs, the TWT SP, which includes a beacon frame trigger, can be repeated multiple times at specific intervals.

[0153] The transmission of TWT messages can be accomplished through TWT message frames and TWT message elements. TWT message frames are sent by STAs to request or transmit information about the TWT agreement, and are sent by one of the STAs within the existing TWT agreement. The action frame of a TWT message frame includes the TWT information field.

[0154] The TWT information field may include a 3-bit TWT stream identifier subfield, a 1-bit response request subfield, a 1-bit next TWT request subfield, a 2-bit next TWT size subfield, a 1-bit full TWT subfield, and a 0 / 32 / 48 / 64-bit next TWT subfield.

[0155] Here, the TWT Stream Identifier subfield can be used to identify the stream that requests / provides TWT information.

[0156] The Response Request subfield indicates whether the sender of a frame that includes the TWT information field requests the transmission of a TWT information frame (to be sent in response to the receipt of that frame). To request the receiver not to send a TWT information frame in response to a received frame, the Response Request subfield value can be set to 0. To request the receiver to send a TWT information frame in response to a received frame, the Response Request subfield value can be set to 1.

[0157] To indicate a request for transmission of a TWT information frame containing the following TWT fields (where the length of the TWT information frame is not 0), the value of the next TWT subfield can be set to 1. Otherwise, the value of the next TWT subfield can be set to 0.

[0158] The Next TWT Subfield Size subfield indicates the size of the next TWT subfield. When the size of the next TWT subfield is 0 / 32 / 48 / 64 bits, the value of the Next TWT Subfield Size subfield can be set to 0 / 1 / 2 / 3.

[0159] HE STA can set all TWT subfield values ​​to 1, which can mean that the TWT information frame has all TWTs that have been realigned. Otherwise, all TWT subfield values ​​can be set to 0.

[0160] Figure 10 This is a diagram used to describe an example of the TWT information element format.

[0161] TWT elements can be sent and received by being included in beacon, probe response, (re)assembled response frames, etc. A TWT element may include an element ID field, a length field, a control field, and a TWT parameter information field.

[0162] The control fields of a TWT element have the same format as both standalone TWTs and broadcast TWTs.

[0163] The NDP paging indicator subfield can have a value of 1 if the NDP paging field is present, and a value of 0 if the NDP paging field is absent.

[0164] The responder's PM mode subfield can indicate the power management (PM) mode.

[0165] The negotiation type subfield can indicate whether the information included in the TWT element is about negotiating the parameters of a broadcast TWT or a separate TWT, or about the wake-up TBTT interval.

[0166] For example, if the value of the Negotiation Type subfield is 0, then the TWT subfield is for a future, separate TWT SP start time, and the TWT element contains a separate set of TWT parameters. This could correspond to a separate TWT negotiation between the TWT request STA and the TWT response STA, or to a separate TWT announcement from the TWT responder.

[0167] For example, if the value of the negotiation type subfield is 1, then the TWT subfield is for the next TBTT time, and the TWT element contains a separate set of TWT parameters. This can correspond to the wake-up TBTT and the wake-up interval negotiation between the TWT-scheduled STA and the TWT-scheduled AP.

[0168] For example, if the value of the negotiation type subfield is 2, then the TWT subfield is for the start time of a future broadcast TWT SP, and the TWT element includes one or more broadcast TWT parameter sets. This can correspond to providing broadcast TWT scheduling to TWT-scheduled STAs by including the TWT element in a broadcast management frame sent by the TWT scheduling AP.

[0169] For example, if the value of the negotiation type subfield is 3, then the TWT subfield is for the future broadcast TWT SP start time, and the TWT element includes one or more broadcast TWT parameter sets. This can correspond to managing broadcast TWT scheduling membership by including the TWT element in a separately addressed management frame sent by either a TWT-scheduling STA or a TWT-scheduling AP.

[0170] If the TWT information frame disable subfield is set to 1, this indicates that the STA's reception of TWT information frames is disabled; otherwise, it can be set to 0.

[0171] The Wake-up Duration Unit subfield indicates the unit of the nominal minimum TWT wake-up duration field. When the unit is 256 µs, the wake-up duration unit subfield can be set to 0, and when the unit is TU, the wake-up duration unit subfield can be set to 1. When it is not an HE / EHT STA, the wake-up duration unit subfield can be set to 0.

[0172] The most significant bit (MSB) of the negotiation type field can correspond to the broadcast field. If the broadcast field is 1, the TWT element can include one or more broadcast TWT parameter sets. If the broadcast field is 0, the TWT element can include only a single TWT parameter set. A TWT element with the broadcast field set to 1 can be called a broadcast TWT element.

[0173] also, Figure 11 The example shown is a reserved field consisting of 2 bits, but this is just an example. For instance, a TWT element may include a link ID bitmap presence field (e.g., 1 bit) and a reserved field (e.g., 1 bit).

[0174] For example, if the Link ID Bitmap Existence field is set to 1, the Link ID Bitmap field is set to exist in the separate TWT parameter set field format, which will be described later, and if the Link ID Bitmap Existence field is set to 0, the Link ID Bitmap field can be set to not exist in the separate TWT parameter set field format.

[0175] Figure 12 This is a diagram illustrating an example of the format of a single TWT parameter set field. Figure 10This is a diagram illustrating an example of the format of the broadcast TWT parameter set fields.

[0176] Included Figure 11 The TWT parameter information field in the TWT element can have different configurations depending on whether it is a separate TWT or a broadcast TWT.

[0177] In the case of a standalone TWT, the TWT parameter information field within the TWT element includes a single, separate TWT parameter set field.

[0178] In the case of broadcast TWTs, the TWT parameter information field in the TWT element includes one or more broadcast TWT parameter set fields. Each broadcast TWT parameter set can include specific information about a broadcast TWT.

[0179] like Figure 12 and Figure 11 As shown, the individual TWT parameter set fields and the broadcast TWT parameter set fields include common subfields.

[0180] The request type subfield has the same size as both the individual TWT parameter set field and the broadcast TWT parameter set field, but can be configured with different detailed settings. This will be described later.

[0181] The Target Wake-up Time subfield indicates the start time of a future scheduled individual / broadcast TWT SP.

[0182] The Nominal Minimum TWT Wake-up Duration subfield indicates the minimum unit of time expected to wake up the TWT requesting STA to complete the frame exchange associated with the TWT stream identifier during the TWT wake-up interval duration. Here, the TWT wake-up interval can mean the average time between consecutive TWT SPs expected by the TWT requesting STA.

[0183] The TWT wake-up interval mantissa subfield is the binary value of the TWT wake-up interval, which can be represented in microseconds.

[0184] Reference Figure 12 The TWT group assignment subfield, TWT channel, and NDP paging subfield are only included in a separate TWT parameter set field.

[0185] The TWT Group Assignment subfield includes information about the TWT group to which the STA is assigned and provides this information to the TWT requesting STA. This information can be used to calculate the TWT value within the TWT group. The STA's TWT value can be equal to the zero offset value and the TWT unit value multiplied by the TWT offset value.

[0186] Here, TWT group information may include a TWT group ID subfield, a zero offset existence subfield, a group zero offset subfield, a TWT unit subfield, and a TWT offset subfield.

[0187] The TWT Group ID subfield indicates the identifier of the TWT group to which the requesting STA is assigned, and a TWT group can refer to a group of STAs that have TSF values ​​within a specific interval of TWT values. If the value of the TWT Group ID subfield is set to 0, it can indicate a unique TWT group for all STAs, including the BSS.

[0188] The Zero Offset Presence subfield indicates whether the zero offset subfield of the group exists. For example, if the value of the Zero Offset Presence subfield is set to 1, it indicates that the zero offset subfield of the group exists. If the value of the Zero Offset Presence subfield is set to 0, it indicates that the zero offset subfield of the group does not exist.

[0189] The zero offset subfield of the group is optional and can indicate the initial TWT value of the TWT group identified by the TWT group ID.

[0190] The TWT Unit subfield can indicate the increment unit of the TWT value within a TWT group identified by the TWT group ID. For example, if the TWT unit time values ​​are 32μs, 256μs, 1024μs, 8.192ms, 32.768ms, and 262.144ms, the TWT Unit subfield values ​​can be expressed as 0, 1, 2, 3, and 4, respectively.

[0191] The TWT offset subfield can indicate the position of the STA corresponding to the RA of the frame that includes the TWT element within a specified group.

[0192] The TWT Channel subfield represents a bitmap indicating the allowed channels. When sent by a TWT request STA, the TWT Channel subfield may include a bitmap indicating the channel the STA requests to be used as a temporary base channel during the TWT SP. When sent by a TWT response STA, the TWT Channel subfield may include a bitmap indicating the channels allowed by the TWT request.

[0193] The NDP paging subfield is optional and may include the identifier of the paged STA, information related to the maximum number of TWT wake-up intervals between NDP paging frames, etc.

[0194] Reference Figure 11The broadcast TWT info subfield is only included in the broadcast TWT parameter set field. The broadcast TWT info subfield may include a 3-bit reserved bit, a 5-bit broadcast TWT identifier (ID) subfield, and an 8-bit broadcast TWT persistence subfield. The broadcast TWT identifier subfield indicates the broadcast ID of the specific broadcast TWT that the STA requests to participate in or provide TWT parameters based on the value of the TWT setup command subfield of the TWT element. The broadcast TWT persistence subfield indicates the number of TBTTs planned on the broadcast TWT scheduler.

[0195] Next, we will describe the specific configuration of the request type subfield.

[0196] First, refer to Figure 12 This will describe the format of the request type subfield for each individual TWT parameter set field.

[0197] The TWT request subfield can indicate whether it is a requesting STA or a responding STA. If the value is 1, it indicates that it is a TWT requesting STA or a scheduling STA, and if the value is 0, it indicates that it is a TWT responding STA or a scheduling AP.

[0198] TWT allows you to create command subfields that can indicate commands such as request, suggestion, requirement, accept, replace, indicate, and reject.

[0199] The trigger subfield indicates whether a trigger frame is used in the TWT SP. If the value is 1, a trigger can be used, and if the value is 0, a trigger can be omitted.

[0200] An implicit subfield can indicate whether it is an implicit TWT or an explicit TWT. If the value is 1, it indicates an implicit TWT, and if the value is 0, it indicates an explicit TWT.

[0201] The Stream Type subfield indicates the type of interaction between the TWT requesting STA (or TWT scheduling STA) and the TWT responding STA (or TWT scheduling AP). If the value is 1, this could mean that in an advertised TWT, the STA sends a wake-up signal to the AP by sending a PS-polling or APSD (Automatic Power Saving Transfer) trigger frame before sending a frame other than the trigger frame from the AP to the STA. If the value is 0, this could mean an unadvertised TWT.

[0202] The TWT Stream Identifier subfield may include a 3-bit value that uniquely identifies specific information about a TWT request in other requests between the same TWT Request STA and TWT Response STA pair.

[0203] The TWT wake-up interval index subfield allows you to set the TWT wake-up interval value in binary microseconds. In the case of a single TWT, this can mean the interval between individual TWT SPs. The TWT wake-up interval for a requested STA can be defined as [TWT wake-up interval mantissa * 2 * TWT wake-up interval index].

[0204] The TWT Protection subfield indicates whether the TWT protection mechanism is used. If the value is 1, the TXOP in the TWT SP can be initiated using the NAV protection mechanism (e.g., (MU)RTS / CTS or CTS-to-self frames), and if the value is 0, the NAV protection mechanism is not applied.

[0205] Reference Figure 12 Some subfields of the Request Type subfield of the Broadcast TWT Parameter Set field are common to the subfields of the Request Type subfield of the Individual TWT Parameter Set field, therefore their descriptions are omitted. The descriptions below only include the subfields included in the Broadcast TWT Parameter Set.

[0206] The Last Broadcast Parameter Set subfield indicates whether it is the last broadcast TWT parameter set. If the value is 1, it indicates that it is the last broadcast TWT parameter set, and if the value is 0, it indicates that there is a next broadcast TWT parameter set.

[0207] The Broadcast TWT Recommendation subfield can provide a recommendation indication for the type of frame sent by the AP during the Broadcast TWT SP with values ​​1-7.

[0208] For example, when the broadcast TWT recommendation subfield value is set to 4, the corresponding broadcast TWT SP can be called an r-TWTSP. That is, a broadcast TWT parameter set where the broadcast TWT recommendation subfield value is set to 4 can be called a restricted TWT parameter set. Here, during the r-TWT SP, the AP and the STA that schedules the member r-TWT can specify the transmission priority of QoS data frames, which are latency-sensitive services. Furthermore, a broadcast TWT element that only includes the r-TWT parameter set field can be called a restricted TWT element.

[0209] The last bit of the request type subfield in the broadcast TWT parameter set field can be preserved.

[0210] As an example of this disclosure, the broadcast TWT parameter set field may include a restricted TWT service information (information) subfield. As an example, the TWT service information subfield may follow the broadcast TWT information field of the broadcast TWT parameter set field, such as... Figure 13 As shown in the diagram.

[0211] As an example of this disclosure, such as Figure 12As illustrated in (a), the broadcast TWT information subfield may include a restricted TWT service information presence subfield and a restricted TWT scheduling complete subfield.

[0212] The TWT service information presence subfield and the restricted TWT scheduling complete subfield can be set in the first bit (B0) and second bit (B1) of the broadcast TWT information field, respectively, such as... Figure 13 As shown in the diagram.

[0213] For example, if the Restricted TWT Service Information field exists in the Broadcast TWT Parameter Set field, the Restricted TWT Service Information Existence subfield value of the Restricted TWT Parameter Set field can be set to 1. Otherwise, the Restricted TWT Service Information Existence subfield value can be set to 0. For non-EHT STAs, the Restricted TWT Service Information Existence subfield can be retained.

[0214] If the Restricted TWT Scheduling Complete Subfield value is set to 1, it indicates that the r-TWT scheduling AP is unlikely to accept a request from a STA in the BSS to establish new membership in that scheduling. Otherwise, the Restricted TWT Scheduling Complete Subfield value can be set to 0.

[0215] If the restricted TWT parameter set field is carried in a TWT element with a negotiation type subfield set to 2 and that TWT element is sent by an EHT AP, then the restricted TWT scheduling complete subfield can be valid.

[0216] If the restricted TWT service information subfield of the broadcast TWT information subfield has a subfield value set to 1, then the restricted TWT service information field can exist in the restricted TWT parameter set field.

[0217] like Figure 13 As illustrated in (b), the restricted TWT business information field may include a business information control subfield, a restricted TWT DL TID bitmap subfield, and a restricted TWT UL TID bitmap subfield.

[0218] like R-TWT membership setup and R-TWT SP announcement As illustrated in (c), the business information control field may include a valid subfield of the DL TID bitmap and a valid subfield of the ULTID bitmap.

[0219] The valid subfield of the DL TID bitmap can be set to 1 to indicate that the restricted TWT DL TID bitmap field is valid. The valid subfield of the DL TID bitmap can be set to 0 to indicate that all DL services mapped to the DL for the link established for r-TWT membership are identified as latency-sensitive services, and the restricted TWT DL TID bitmap field is reserved.

[0220] The UL TID bitmap valid subfield can be set to 1 to indicate that the restricted TWT UL TID bitmap field is valid. The UL TID bitmap valid subfield can be set to 0 to indicate that all UL services mapped to the UL TID used to establish r-TWT membership are identified as latency-sensitive services, and the restricted TWT UL TID bitmap field is reserved.

[0221] The restricted TWT DL TID bitmap and restricted TWT UL TID bitmap subfields can specify the TID of the delay-sensitive service flow in the DL and UL directions, respectively, as identified by the r-TWT scheduling AP or the R-TWT scheduling STA.

[0222] A value of 1 at bit position k in the bitmap indicates that TID k is classified as a latency-sensitive traffic flow. A value of 0 at bit position k in the bitmap indicates that TID k is not classified as a latency-sensitive traffic flow.

[0223] TXOP and backoff procedure rules for R-TWT SP

[0224] R-TWT membership can be established using the same procedure used to establish broadcast TWT membership, except that the broadcast TWT element carried on the TWT setup frame includes one or more restricted TWT parameter set fields. The R-TWT scheduling AP can set the trigger field to 1 in the R-TWT parameter set fields it transmits. When included in a separately addressed TWT setup frame transmitted by an R-TWT scheduling AP or R-TWT scheduling STA, the R-TWT service information presence subfield of the broadcast TWT information field included in the R-TWT parameter set field can be set to 1.

[0225] R-TWT scheduling AP and R-TWT scheduling STA can set a restricted TWT service information field to identify the TID of delay-sensitive services carried in the DL and UL used for the established R-TWT membership.

[0226] When R-TWT membership is established, an EHT AP can advertise R-TWT scheduling information by including a restricted TWT parameter set field in the broadcast TWT element included in its transmitted management frames. Membership can be established with non-transmitting APs belonging to the same set of multiple BSSIDs or co-hosted BSSIDs as the associated EHT AP or transmitting AP. Transmitted BSSIDs in the multiple BSSID set can include all R-TWT schedules advertised for the transmitting BSSIDs and all non-transmitting BSSIDs in the same multiple BSSID set.

[0227] When the negotiation type subfield of a TWT element is 2, an R-TWT scheduling AP that includes an R-TWT parameter set field in a broadcast TWT element can set the restricted TWT service information presence subfield of the restricted TWT parameter set field to 0. Non-AP STAs cannot request membership establishment in an R-TWT schedule published by an R-TWT scheduling AP with a restricted TWT scheduling subfield set to 2. The R-TWT scheduling AP can determine the start time (next R-TWT SP start time) of an R-TWT SP occurring after the first R-TWT SP in a periodic R-TWT schedule based on the start time of the first R-TWT SP and the TWT wake-up interval of the corresponding R-TWT schedule.

[0228] Silence interval associated with R-TWT SP

[0229] Setting “dot11RestrictedTWTOptionImplemented” to true for non-AP EHT STAs (e.g., TXOP holders) ensures that the TXOP ends before the start time of the active R-TWT SP published by the associated AP or the AP corresponding to the BSSID in the multi-BSSID set to which the associated AP belongs.

[0230] Here, TXOP refers to the time interval during which a specific STA is entitled to initiate a frame exchange sequence on the radio medium (WM). TXOP can be defined by a start time (during which the STA may be entitled) and a maximum duration value.

[0231] Furthermore, a TXOP holder refers to an STA that has been granted a TXOP by the HC (Hybrid Coordinator) or has successfully competed for a TXOP. In other words, a TXOP holder is an STA that has the right to perform a frame exchange sequence within a TXOP. A TXOP responder is an STA that sends a frame during a frame exchange sequence in response to a frame received from a TXOP holder, but has not yet acquired a TXOP during this process.

[0232] Additionally, before initiating PPDU transmission, non-AP EHT STAs with "dot11RestrictedTWTOptionImplemented" set to true can check if there is sufficient time to complete frame switching before R-TWT SP initiation; and if not sufficient time, the STA can postpone transmission (without advancing to the next value in the sequence) by using the current CW to select a random backoff count. R-TWT scheduling that is advertised in beacon or probe response frames and is not in non-transmitted BSSID profiles can include scheduling for both transmitted and non-transmitted BSSIDs.

[0233] An EHT AP (i.e., the TXOP holder) with “dot11RestrictedTWTOptionImplemented” set to true can ensure that the TXOP ends before the start time of its own published R-TWT SP activity, as long as the remainder of the TXOP belonging to the R-TWT SP is not used to forward DL frames for R-TWT DL TID or UL frames requesting R-TWT UL TID.

[0234] When an R-TWT SP is started, a member STA can pause the decrement of the backoff counter for an AC that does not have a mapped R-TWT TID until all frames in the R-TWT TID have been transmitted, and the member STA can resume decrementing thereafter or when the SP terminates.

[0235] Multi-Access Point (MAP) operation

[0236] The R-TWT scheduling AP can schedule a silence interval of up to one overlapping R-TWT SP, wherein the (overlapping) silence interval has a duration of 1 time unit (TU) and can start simultaneously with the R-TWT SP.

[0237] To address overlapping silence intervals of one or more R-TWT SP schedules belonging to one or more periodic or aperiodic R-TWT schedules, the EHT AP can do so by sending one or more silence elements in beacon frames and probe response frames.

[0238] EHT APs associated with an AP MLD may not include any silence element in their transmitted beacon frames or probe response frames that corresponds to overlapping silence intervals scheduled and published by other APs belonging to the same AP MLD. Non-AP EHTSTAs may behave as if overlapping silence intervals do not exist.

[0239] Method for protecting OBSS R-TWT in multi-BSS

[0240] The following describes an example of this disclosure for multi-access point (MAP) operation.

[0241] MAP operation can be a general term for techniques used by multiple APs / STAs to cooperate in sending and receiving data while communicating with other STAs. MAP operation can include a first method (i.e., a multi-AP / STA co-transmission method) in which multiple APs simultaneously send data to a STA; and a second method (i.e., a multi-AP / STA coordination method) in which an appropriate AP among the multiple APs divides an appropriate area (e.g., a frequency / time / spatial area) and then sends data to a specific STA (i.e., the appropriate STA).

[0242] Specifically, the first method may include a method in which multiple APs / STAs communicate with each STA simultaneously (e.g., a coordinated spatial multiplexing (C-SR) method) and a method in which multiple APs / STAs perform joint transmissions to the same STA (e.g., a joint transmission (J-TX) method).

[0243] In the C-SR method, multiple APs / STAs share channel information with the STA (e.g., transmit power (Tx power), RSSI (Received Signal Strength Indicator), etc.) and can communicate with the STA simultaneously based on this channel information. In the J-TX method, multiple APs / STAs share channels and data with the STA and can communicate with the STA simultaneously based on the shared channels and data.

[0244] As mentioned above, the second method refers to the method of dividing the AP / STA into frequency domain, time domain, or spatial domain and communicating with other STAs in the divided domain. Frequency domain-based communication methods may include the C (Coordination)-OFDMA method; time domain-based communication methods may include AP selection, relay operation, C (Coordination)-TDMA (Time Division Multiple Access), V (Virtual)-BSS method, etc.; and spatial domain-based communication methods may include the C (Coordination)-BF (Beamforming) method, etc.

[0245] For example, in frequency-domain-based communication methods, multiple APs / STAs can share channel information with a STA based on the frequency band, and select an appropriate frequency band based on the shared channel information. Multiple APs / STAs can then communicate with the STA within the selected frequency band.

[0246] As another example, in the case of time-domain-based communication methods, a representative AP can be set up to lead the communication by having the STA select the appropriate AP / STA (here, also including the representative AP).

[0247] As another example, in the case of spatial domain-based communication methods, multiple APs / STAs can share channel information with a STA and calculate a BF matrix suitable for each AP's communication or that will not interfere with other APs. Multiple APs / STAs can then communicate with the STA based on the calculated BF matrix.

[0248] To support the MAP operations described above, the representative AP can select and instruct the AP / STA (hereinafter referred to as the participating AP / STA) to communicate with the STA.

[0249] The representative AP (here, the representative AP can be replaced by the primary AP, shared AP, or main AP) initiates and controls MAP operations for transmission and reception among multiple APs. The representative AP groups participating APs and manages links with them, enabling information sharing among the participating APs. The representative AP manages information about the BSS comprised of the participating APs and about the STAs associated with the BSS.

[0250] Participating APs (which can be replaced by slave APs, shared APs, or auxiliary APs) are associated with the representative AP and can share control information, management information, and data services with each other. Participating APs perform the same basic functions as APs capable of establishing a BSS in a wireless LAN.

[0251] In MAP operations, participating STAs can be associated with participating APs or representative APs to form BSSs.

[0252] In a MAP environment, the representative AP and participating APs can directly send and receive data from each other. The representative AP and STA may not be able to directly send and receive data from each other. A participating AP (e.g., a participating AP associated with a STA) can directly send data to and receive data from the STA. One of the participating APs can become the representative AP.

[0253] Figure 14

[0254] In a multi-BSS environment, the range of an overlapping BSS (hereinafter referred to as OBSS) is formed / set based on the range of frames (e.g., beacon frames, etc.) that a STA can receive from one or more APs.

[0255] For example, as shown below Figure 15 As illustrated in the diagram, the signaling ranges of AP 1 and AP 2 may overlap, and STAs within this range (e.g., STA 1-2 or / and STA 2-4) can receive beacon frames sent by AP 1 within their associated BSS 1 as well as beacon frames of AP 2 within their unassociated BSS 2.

[0256] Here, AP 1 and AP 2 can be slave APs belonging to a multi-AP group with the same master AP, but are not limited to this. Either AP 1 or AP 2 can be a master AP.

[0257] The AP can send a beacon frame containing the scheduling information of the R-TWT to the corresponding STA. At this time, the STA receiving the beacon frame can be within the range protecting the R-TWT SP. For example, the STA can protect the R-TWT SP based on the R-TWT scheduling information received from the AP using the method described above.

[0258] However, a STA located within the range corresponding to the OBSS may receive beacon frames from a neighboring AP (i.e., an AP to which the STA is not associated with the BSS) (e.g., AP 2), and these beacon frames may include R-TWT (hereinafter, OBSS R-TWT) scheduling information generated by the neighboring AP. Previously, there was a problem that not only was a method for STAs to protect the OBSS R-TWTSP not defined, but also a method for transmitting and receiving low-latency services / data during the OBSS R-TWTSP was not defined.

[0259] The following will describe various operations (e.g., OBSS R-TWT SP protection operations, etc.) of the AP (e.g., AP 1) of the BSS to which the STA is connected, based on the R-TWT scheduling information of the neighboring AP (OBSS).

[0260] In describing this disclosure, a STA may include both non-AP STAs and AP STAs, and an R-TWT SP announced by an AP of a BSS to which the STA is not associated may be referred to as an OBSS R-TWT SP or an R-TWT SP scheduled by another AP. Additionally, an associated AP may mean the AP of the BSS to which the STA is associated (i.e., the BSS AP).

[0261] Figure 15 This is a flowchart illustrating the operation of a STA according to an embodiment of the present disclosure. Here, the STA may be associated with the BSS of a first AP. That is, from the perspective of the STA, the second AP may be a neighboring AP. The STA may be located in the area where the BSS of the first AP and the BSS of the second AP overlap, but is not limited thereto.

[0262] The STA can receive a first frame (S1510) from the first access point (AP), which includes a first broadcast target wake-up time (TWT) parameter set field and a second broadcast TWT parameter set field. Here, the first frame may include, but is not limited to, a management frame such as a beacon frame.

[0263] As an example of this disclosure, a first broadcast TWT parameter set field (i.e., the broadcast parameter set associated with a first R-TWTSP scheduled by a first AP) and a second broadcast TWT parameter set field (i.e., the broadcast parameter set associated with a second R-TWT SP (i.e., OBSS R-TWT SP) scheduled by a second AP) may be included in a single TWT element (e.g., a first TWT element) included in the first frame. That is, the first TWT element may include multiple broadcast parameter sets, including both the first and second broadcast parameter sets. In this case, the second broadcast parameter set may be, but is not limited to, the last broadcast parameter set among the multiple broadcast parameter sets included in the first TWT element of the first frame.

[0264] In another example of this disclosure, the first frame may include a second TWT element and a third TWT element, the first broadcast parameter set may be included in the second TWT element, and the second broadcast parameter set may be included in the third TWT element. That is, the first broadcast parameter set and the second broadcast parameter set may both be included in separate TWT elements.

[0265] For example, the first information and the first broadcast TWT ID associated with the first R-TWT SP scheduled by the first AP can be included in the first broadcast TWT parameter set, and the second information and the second broadcast TWT ID associated with the second R-TWT SP scheduled by the second AP can be included in the second broadcast TWT parameter set. That is, the first broadcast TWT ID can correspond to the first information, and the second broadcast TWT ID can correspond to the second information. In this way, the STA (e.g., a UHR STA supporting enhanced R-TWT, etc.) can distinguish between the first information and the second information.

[0266] For example, if a first broadcast TWT parameter set and a second broadcast TWT parameter set are included on a first TWT element, the STA can identify the second broadcast parameter set, which includes information related to the second R-TWT SP, using the second broadcast TWT ID. That is, the STA can identify the second broadcast parameter set included in the third TWT element (i.e., the second broadcast parameter set including the second broadcast TWT ID) on the first TWT element using the second broadcast TWT ID. As another example, the STA can identify the second broadcast parameter set on the first TWT element as being associated with the second R-TWT SP using the second broadcast TWT ID corresponding to / mapped to / defined in the second R-TWT SP.

[0267] In another example of this disclosure, the inclusion of second information in a first TWT element can be indicated by a TWT recommendation field included in the first TWT element of the first frame. For example, information indicating that the second information is included in the first TWT element can be mapped to / correspond to reserved values ​​(e.g., 5 to 7) of the TWT recommendation field. In another example, the inclusion of second information in a third TWT element can be indicated by a TWT recommendation field included in the third TWT element.

[0268] In another example of this disclosure, the inclusion of second information in the WP1 TWT element can be indicated by the NDP Paging Indicator subfield and the Responder Power Management (PM) subfield included in the control field of the first TWT element. In another example, the inclusion of second information in the third TWT element can be indicated by the NDP Paging Indicator subfield and the Responder Power Management (PM) subfield included in the control field of the third TWT element.

[0269] The first STA can decode the first frame (S1520). The first STA can perform operations to protect the second R-TWT SP based on the information included in the first frame.

[0270] For example, a STA can terminate its transmission opportunity (TXOP) before the start time of the second R-TWT SP.

[0271] For example, the broadcast TWT information (info) subfield of the second broadcast TWT parameter set may include an R-TWT scheduling information subfield, and this R-TWT scheduling information subfield may include information indicating that membership requests associated with the second R-TWT SP via the STA are not permitted. Therefore, membership requests based on the second broadcast TWT ID associated with the second R-TWT SP of the STA can be blocked.

[0272] As another example, the R-TWT information subfield included in the broadcast TWT information subfield of the second broadcast TWT parameter set may include information indicating that the second information is related to a second R-TWT SP scheduled by a second AP corresponding to an unsent BSSID.

[0273] As another example, the value of the broadcast TWT persistence subfield included in the second broadcast parameter set field can be set to a predefined minimum value (e.g., 1, etc.).

[0274] Figure 1 The method described in the example, executed by STA, can be performed by Figure 1 The first device (100) executes. For example, Figure 15One or more processors (102) of the first device (100) can receive a first frame, including a first broadcast TWT parameter set field and a second broadcast TWT parameter set field, from the first access point (AP) via one or more transceivers (106). The one or more processors (102) can decode the first frame.

[0275] The memory (104) above is capable of storing data for execution when carried out by one or more processors (102). Figure 16 The instructions for the methods described in the example.

[0276] Figure 15 This is a diagram used to describe the operation of a first AP according to an embodiment of the present disclosure.

[0277] The first AP can receive second information related to the second restricted target wake-up time (R-TWT) service period (SP) from the second AP (S1610).

[0278] Receiving second information from a second AP may include the action of the first AP receiving the second information via another entity.

[0279] The first AP can send a first beacon frame (S1620) to the first STA, which includes first information and second information related to the first R-TWT SP.

[0280] Already referenced Figure 16 The first beacon frame, which describes the first AP sending configuration to the first STA to protect / process the second R-TWT SP, is described; therefore, any repeated descriptions will be omitted.

[0281] Figure 1 The method described in the example, executed by the second STA, can be performed by... Figure 10 The second device (200) performs the operation. For example, Figure 16 One or more processors (202) of the second device (200) can receive second information related to the second R-TWT SP from the second AP via one or more transceivers (206). One or more processors (202) can send a first beacon frame including first information and second information related to the first R-TWT SP to the first STA via one or more transceivers (206).

[0282] Furthermore, one or more memories (204) of the second device (200) may store instructions for execution when executed by one or more processors (202). Figure 15 The method described in the example.

[0283] In the following text, reference will be made to Figure 16 and Embodiment 1Specifically, describe the method by which the STA and the first AP process OBSS R-TWT scheduling information.

[0284] Figure 15

[0285] In the following text, reference will be made to Figure 16 and Embodiment 2 Specifically, describe the method by which the STA and the first AP process OBSS R-TWT scheduling information.

[0286] Method 1: When direct wired / wireless data transmission and reception between APs (i.e., associated APs and neighboring APs) is possible, the associated AP can send its R-TWT scheduling information to the neighboring AP or receive OBSS R-TWT scheduling information from the neighboring AP.

[0287] Method 2: If direct wired / wireless data transmission and reception between APs is not possible, the APs can share R-TWT scheduling information through a third-party management entity. In other words, APs can share R-TWT scheduling information by using a third-party management entity as a relay entity.

[0288] For example, APs can be located within the same ESS. Within the same ESS, where multiple BSSs are connected to a single DS, a third-party management entity can provide the same services (e.g., centralized services). Therefore, a third-party management entity relaying APs within the same ESS can function as a master AP or network controller.

[0289] As another example, an AP can be a slave AP (i.e., a shared AP or / and a scheduled AP) of the same AP as the master AP (i.e., a shared AP or / or a scheduled AP). In this case, the third management entity can be the master AP.

[0290] Method 3: The STA can listen to beacon frames advertised by neighboring APs and decode the listened-to beacon frames. Then, the STA can send the information related to the OBSS R-TWT SP included in the decoded beacon frames to the associated AP.

[0291] Figures 8 to 13

[0292] Example 2 relates to a method for protecting OBSS R-TWT by classifying STA types according to whether or not R-TWT is supported.

[0293] Depending on whether R-TWT is supported, STA types can be classified as follows:

[0294] - Pre-EHT STA that does not support R-TWT: This refers to a STA that has Pre-EHT capability and can correspond to a legacy STA.

[0295] - EHT STA that does not support R-TWT: This is a STA with EHT capability and can correspond to a STA that does not support R-TWT.

[0296] - EHT STA supporting R-TWT: This is a STA with EHT capability and can correspond to a STA supporting R-TWT. In this case, the EHT STA supporting R-TWT can be defined / configured to disregard protection operations for OBSS R-TWT SPs.

[0297] Additionally, UHR STAs (or STAs on wireless LAN systems based on IEEE 802.11be or later) can be classified based on whether they support R-TWT and / or OBSS R-TWT. For example, a UHR STA can send capability information to another STA (e.g., an AP) indicating whether it supports R-TWT and / or OBSS R-TWT, and the type of UHR STA can be classified based on this capability information.

[0298] - UHR STA that does not support R-TWT: This is a STA with UHR capability and can correspond to a STA that does not support R-TWT.

[0299] - UHR STA that only supports R-TWT: This can correspond to a STA with UHR capability but only supports R-TWT (i.e., operations and parameters related to R-TWT, such as...). Embodiment 2-1 (As illustrated in the diagram). A UHR STA that only supports R-TWT may, but is not limited to, be unable to decode information related to OBSS R-TWT (e.g., information related to enhanced R-TWT). A UHR STA that only supports R-TWT may also be able to decode information related to OBSS R-TWT.

[0300] - UHR STA supporting Enhanced R-TWT: This corresponds to a STA that supports UHR capability and enhanced R-TWT operation. Enhanced R-TWT operation may include protection operations for OBSS R-TWT SP, etc.

[0301] Figure 17

[0302] Example 2-1 relates to a method for protecting OBSS R-TWT SPs for STA classification in Example 2. The method for protecting OBSS R-TWT SPs can be defined / applied by extending the methods described above for STA reporting R-TWT SPs (e.g., overlapping silence intervals and / or TXOP and backoff procedure rules for R-TWT SPs, etc.).

[0303] Here, the TXOP and backoff procedure rules for R-TWT can include rules for the STA (i.e., the TXOP holder) to send and receive data during a TXOP that begins before the R-TWT start time in order to stop that TXOP. The R-TWT TXOP and backoff procedure rules can also be applied to the OBSS R-TWT SP in the same way. That is, rules can be defined for the STA (i.e., the TXOP holder) to send and receive data during a TXOP that begins before the OBSS R-TWT start time in order to stop that TXOP.

[0304] Additionally, an overlapping silent interval can refer to a silent interval allocated to overlap with the R-TWT SP within the same time period. The BSS AP can set the silent interval to overlap with the OBSS R-TWT SP obtained by the method of obtaining the OBSS R-TWT scheduling information disclosed in Example 1. For example, an R-TWT scheduling AP (e.g., a BSS AP) can set at least one (or at most one) overlapping interval that overlaps with the R-TWT SP and / or the OBSS R-TWT SP.

[0305] The following describes a method for protecting OBSS R-TWT SP by means of the STA type classified in Example 2.

[0306] - Pre-EHT STA that does not support R-TWT: This STA can protect the OBSS R-TWTSP by overlapping silence intervals. For example, a Pre-EHT STA that does not support R-TWT can protect the OBSS R-TWT SP (by overlapping silence intervals set by the BSS AP to include the OBSS R-TWT SP).

[0307] - EHT STA that does not support R-TWT: This STA can protect the OBSS R-TWT SP by using an overlapping silence interval. For example, an EHT STA that does not support R-TWT can protect the OBSS R-TWT SP (by using an overlapping silence interval set by the BSS AP to include the OBSS R-TWT SP).

[0308] - EHT STAs supporting R-TWT: The behavior of R-TWT-enabled EHT STAs can be determined based on whether the BSS AP advertises information about OBSS R-TWT SPs (i.e., R-TWT SPs scheduled / assigned by neighboring APs) along with information about R-TWT SPs assigned by the BSS AP. Option 1 involves the scenario where the BSS AP advertises OBSS R-TWT SPs along with information about R-TWT SPs assigned by the BSS AP to the STA, and Option 2 involves the scenario where the BSS AP does not advertise OBSS R-TWT SPs along with information about R-TWT SPs assigned by the BSS AP to the STA.

[0309] - Option 1: When the BSS AP provides the OBSS R-TWT SP along with the R-TWT SP information assigned by the BSS AP to the STA, the STA can protect the OBSS R-TWT SP by stopping the TXOP that was in progress before the OBSS R-TWT SP based on the TXOP and backoff procedure rules of the R-TWT SP.

[0310] The BSS AP can configure OBSS R-TWT SP information in the same way as R-TWT SP information, making it possible for STAs to be unable to distinguish between OBSS R-TWT SP and R-TWT SP. However, the BSS AP can configure OBSS R-TWT SP information to correspond to a specific broadcast TWT ID value. In this case, the broadcast TWT ID corresponding to the OBSS R-TWT SP information may not overlap with the broadcast TWT ID corresponding to the R-TWT SP information allocated / scheduled by the BSS AP (i.e., the R-TWT SP information allocated by the BSS AP within its BSS).

[0311] For example, setting "dot11RestrictedTWTOptionImplemented" to true for a non-AP EHT STA (i.e., the TXOP holder) can ensure that the TXOP ends before the start time of the active R-TWT SP, which may include R-TWT SPs scheduled / published by APs corresponding to BSSIDs sent in the associated AP or the multi-BSSID set to which the associated AP belongs, and / or R-TWT SPs scheduled / published by (other) APs included in the multi-AP set.

[0312] Here, the broadcast TWT element including OBSS R-TWT SP information may include a broadcast TWT information (Info) subfield, and the broadcast TWT information subfield may include a restricted TWT scheduling information subfield. The BSS AP may set the value of the restricted TWT scheduling information subfield to indicate a complete R-TWT scheduling. Here, the complete R-TWT scheduling indicated by the restricted TWT scheduling information subfield may mean an R-TWT scheduling that cannot accept new membership requests from STAs. This prevents STAs from requesting membership based on the broadcast TWT ID including OBSS R-TWT SP information.

[0313] Alternatively, the BSS AP may set the value of the restricted TWT scheduling information subfield to a value indicating that the corresponding R-TWT SP was scheduled by the AP corresponding to the unsent BSSID (e.g., 3). This allows the STA associated with the AP corresponding to the sent BSSID to identify the corresponding R-TWT SP (i.e., OBSS R-TWT SP) as not being scheduled by the AP of its BSS.

[0314] According to the above method, a STA associated with a BSS that has been notified of an R-TWT SP can identify the OBSS R-TWT SP information as information about an SP assigned by other R-TWT members (e.g., an AP of a BSS to which the STA itself does not belong).

[0315] Option 2: If the BSS AP does not announce the OBSS R-TWT SP (i.e., the OBSS R-TWT SP scheduled by the neighboring AP) along with information about its already allocated R-TWT SPs to the STA, then the EHT STA that supports R-TWT can protect the OBSS R-TWT SP by including the OBSS R-TWT SP in the overlapping silence interval set by the BSS AP.

[0316] - UHR STA that does not support R-TWT: This STA can protect the OBSS R-TWT SP by including the OBSSR-TWT SP through the overlapping silent interval set by the BSS AP.

[0317] - UHR STA that only supports R-TWT: The operation of a UHR STA that only supports R-TWT may depend on whether the BSS AP announces information about the OBSS R-TWT SP (i.e., the R-TWT SP scheduled / assigned by the neighboring AP) together with information about the R-TWT SP assigned by the BSS AP.

[0318] As an example of this disclosure, when the BSS AP notifies the corresponding STA of the OBSS R-TWT SP along with information about the R-TWT SP allocated by the BSS AP, the corresponding STA can protect the OBSS R-TWT SP by stopping the TXOP that was in progress before the OBSS R-TWT SP based on the TXOP and backoff procedure rules of the R-TWT SP.

[0319] The BSS AP can configure the OBSS R-TWT SP information in the same way as the R-TWT SP information, making it possible for the STA to be unable to distinguish between the OBSS R-TWT SP and the R-TWT SP. However, the BSS AP can configure the OBSS R-TWT SP information to correspond to a specific broadcast TWT ID value. In this case, the broadcast TWT ID corresponding to the OBSS R-TWT SP information cannot overlap with the broadcast TWT ID corresponding to the R-TWT SP information allocated / scheduled by the BSS AP (i.e., the R-TWT SP information allocated by the BSS AP within its BSS).

[0320] Here, the broadcast TWT element including OBSS R-TWT SP information may include a broadcast TWT information subfield, and this broadcast TWT information subfield may include a restricted TWT scheduling information subfield. The BSS AP may set the value of the restricted TWT scheduling information subfield to indicate a full R-TWT scheduling. In this case, the full R-TWT scheduling indicated by the restricted TWT scheduling information subfield may mean an R-TWT scheduling that cannot accept new membership requests from STAs. This prevents STAs from requesting membership based on the broadcast TWT ID including OBSS R-TWT SP information.

[0321] As another example of this disclosure, if the BSS AP does not notify the STA of information about the R-TWT SP (i.e., OBSSR-TWT SP) allocated by the neighboring AP, together with information about the R-TWT SP allocated by the BSS AP, the STA can protect the OBSS R-TWT SP by including the OBSS R-TWT SP in the overlapping silence interval set by the BSS AP.

[0322] Alternatively, the BSS AP may set the value of the restricted TWT scheduling information subfield to a value indicating that the corresponding R-TWT SP was scheduled by the AP corresponding to the unsent BSSID (e.g., 3). This allows the STA associated with the AP corresponding to the sent BSSID to identify the corresponding R-TWT SP (i.e., OBSS R-TWT SP) as not being scheduled by the AP of its BSS.

[0323] As another example of this disclosure, if the BSS AP does not notify the STA of information about the R-TWT SP allocated by the neighboring AP (i.e., the OBSS R-TWT SP) along with information about the R-TWT SP allocated by the BSS AP, the STA can protect the OBSS R-TWT SP by including the OBSS R-TWT SP in the overlapping silence interval set by the BSS AP.

[0324] According to the above method, the STA associated with the BSS that has been notified of the R-TWT SP can identify the OBSS R-TWT SP information as information about the SP assigned by other R-TWT members (e.g., the AP of the BSS to which the STA itself does not belong).

[0325] As an example of this disclosure, assume that the STA requests membership based on the broadcast TWT ID corresponding to the OBSS R-TWT SP information. In this case, the AP may reject the membership request based on the broadcast ID corresponding to the OBSS R-TWT SP.

[0326] - Support for UHR STA of enhanced R-TWT: STA can protect OBSS R-TWT SP based on the TXOP and backoff process rules of R-TWT SP.

[0327] For example, setting "dot11RestrictedTWTOptionImplemented" to true for a non-AP EHT STA (e.g., a TXOP holder) can ensure that the TXOP ends before the start time of the active R-TWT SP published by the associated AP, the AP corresponding to the BSSID sent in the multi-BSSID set to which the associated AP belongs, or the AP included in the same multi-AP set (or a non-associated AP / neighboring AP).

[0328] For example, such as Embodiment 3As illustrated, a UHR STA (e.g., STA 1) that supports enhanced R-TWT can terminate its TXOP before the start time of the OBSS R-TWT SP to protect the OBSS R-TWT SP (i.e., the R-TWT SP scheduled by the neighboring AP (e.g., AP 2)) announced by the AP of the BSS to which the STA is associated (i.e., the associated AP) (e.g., AP 1).

[0329] As an example of this disclosure, the UHR STA supporting enhanced R-TWT can protect the OBSS R-TWT SP through overlapping silent intervals.

[0330] For example, if a UHR STA supporting Enhanced R-TWT does not receive a beacon frame and is therefore unaware that a specific silence interval overlaps with the OBSS R-TWT SP, the UHR STA supporting Enhanced R-TWT can protect the OBSS R-TWT SP by operating according to the silence interval assigned by the AP (e.g., the BSS AP). In this case, information related to the silence interval assigned by the AP can be sent to the STA in a frame separate from the beacon frame.

[0331] As described above, when an AP (e.g., a BSS AP) announces an R-TWT SP that includes information about an OBSS R-TWT SP, an EHT STA that supports R-TWT and / or a UHR STA that only supports R-TWT can recognize that the OBSS R-TWT SP is also an SP of a separate R-TWT member assigned by the AP.

[0332] Here, the STA can request membership through the R-TWT member corresponding to the OBSS R-TWT SP. Because the SP and / or STA correspond to inter-BSS, the STA may not belong to / correspond to the broadcast TWT ID corresponding to the OBSS R-TWT SP. In this case, the AP (e.g., the BSS AP) can operate in one or more of the following ways.

[0333] - If a STA makes a membership request based on the broadcast TWT ID corresponding to the OBSS R-TWT SP, the AP may reject the membership request.

[0334] - The AP can send information about the R-TWT SP to the corresponding STA via beacon frames. Here, the restricted TWT element including the OBSSR-TWT SP can include a broadcast TWT information subfield, and the value of the broadcast TWT persistence subfield of this broadcast TWT information subfield can be set to a minimum value (e.g., 1). Setting the value of the broadcast TWT persistence subfield to a minimum value means that the validity period of the corresponding R-TWT SP can only exist before the next beacon interval. This prevents the corresponding STA from making a membership request based on the broadcast TWT ID corresponding to the corresponding R-TWT SP.

[0335] Here, the minimum value set by the AP in the broadcast TWT persistence subfield within the restricted TWT element, including the OBSS R-TWT SP, can be independent of the actual duration for which the OBSS R-TWT SP can exist. This prevents AP from being overloaded by a large number of STAs due to membership requests for the broadcast TWT ID corresponding to the OBSS R-TWT SP.

[0336] Embodiment 3-1

[0337] In one embodiment of this disclosure, the AP may notify the STA of information regarding R-TWT SPs scheduled / assigned by the AP and information regarding OBSS R-TWT SPs. In this case, if the STA is a STA that supports enhanced R-TWT (e.g., a UHR STA that supports enhanced R-TWT), the STA can distinguish between OBSS R-TWT SPs and R-TWT SPs assigned by the AP. The AP (e.g., a BSS AP) may indicate to the STA (the STA associated with the BSS) that a particular R-TWT SP is an OBSS R-TWT SP by one of the methods described in the following embodiments (Examples 3-1, 3-2, and 3-3).

[0338] Method 1

[0339] Method 2:As an example of this disclosure, the broadcast TWT information subfield may include a restricted TWT service information presence subfield. Because the restricted TWT service information subfield is not included in the beacon frame, the value of the restricted TWT service information presence subfield of the broadcast TWT information subfield included in the beacon frame can always be set to 0. As another example, when the value of the restricted TWT service information presence subfield included in the beacon frame is set to 1, this may mean that the broadcast TWT element included in the beacon frame includes information related to an R-TWT SP scheduled by a neighboring AP (i.e., OBSS R-TWT SP). In other words, a restricted TWT service information presence subfield set to 1 in the beacon frame may not necessarily mean that the broadcast TWT element has a restricted TWT service information subfield, but rather that the broadcast TWT element is related to an R-TWT SP scheduled by a neighboring AP.

[0340] Method 3: Alternatively, as an example of this disclosure, OBSS R-TWT SP information can be associated with specific broadcast TWT ID values, such that a STA (e.g., a UHR STA supporting enhanced R-TWT) can identify that the OBS R-TWT SP information is about an R-TWT SP scheduled by a neighboring AP. APs within a BSS can set broadcast TWT IDs corresponding to each R-TWT SP information allocated within their BSS and broadcast TWT IDs corresponding to the OBSS R-TWT SP information (scheduled by a neighboring AP) such that they do not overlap.

[0341] Alternatively, the repetition of broadcast TWT IDs within the broadcast TWT parameter set field, which includes one or more OBSS R-TWT scheduling information, may be unrestricted. That is, there may be multiple corresponding broadcast TWT IDs for each of multiple OBSS R-TWT schedules. As another example, there may be a single broadcast TWT ID corresponding to multiple OBSS R-TWT schedules.

[0342] Alternatively, i) indicating that it is a specific broadcast TWT ID of an OBSS R-TWT SP, and ii) the values ​​of the NDP paging indicator subfield and the responder PM mode subfield of the control field within the TWT element can be utilized. That is, the value of the broadcast TWT parameter set field can be set to indicate that it is a broadcast TWT ID of an OBSS R-TWT SP, and the combination of the values ​​of the NDP paging indicator subfield and the responder PM mode subfield on the control field of the TWT element, which includes the corresponding broadcast TWT parameter set field, can indicate the presence of a broadcast TWT parameter set field that includes the OBSS R-TWT schedule within the corresponding TWT element. For example, the combination of the values ​​of the NDP paging indicator subfield and the responder PM mode subfield can be (1, 0) or (0, 0).

[0343] Embodiment 3-2 Alternatively, in one embodiment of this disclosure, a reserved value (e.g., 5 to 7) of the broadcast TWT recommendation field in the broadcast TWT element may indicate that the scheduling information contained in the broadcast TWT element is about R-TWT SPs (e.g., OBSS R-TWT SPs) scheduled by neighboring APs.

[0344] For example, when the value of the Broadcast TWT Recommendation field within the Broadcast TWT element indicates the OBSS R-TWT SP, the (sub)fields within the Broadcast TWT Parameter Set field can be interpreted / defined as follows.

[0345] For example, subfields within a broadcast TWT parameter set field (e.g., TWT request subfield, TWT setup command subfield, trigger subfield, stream type subfield, and / or ordered subfields included in the request type field, etc.) can be replaced with subfields related to OBSS R-TWT scheduling included within the corresponding broadcast TWT parameter set field (e.g., subfields including information for OBS R-TWT scheduling and / or information indicating the presence of OBSS R-TWT scheduling information, etc.). As another example, reserved subfields within a broadcast TWT parameter set field can be replaced with subfields related to OBSS R-TWT scheduling.

[0346] Information used for OBSS R-TWT scheduling may include information related to the BSS color of the OBSS R-TWT SP / scheduled OBSS AP, information related to the bandwidth on which the OBSS R-TWT SP / scheduled will operate, and / or information related to the channel on which the OBSS R-TWT scheduling will operate.

[0347] Specifically, the overprotection problem for the OBSS R-TWT SP can be addressed by using information related to the BSS color of the scheduled OBSS R-TWT SP / the scheduled OBSS AP. For example, if a BSS STA (i.e., the STA associated with that BSS) never receives a PPDU with a specific BSS color A, then that BSS STA may not need to stop its TXOP before the start of the OBSS R-TWT SP corresponding to BSS color A. That is, the fact that the BSS STA never receives a PPDU with a specific BSS color A may mean that the BSS STA is in a position unaffected by the OBSS R-TWT scheduling.

[0348] Information related to the bandwidth on which the corresponding OBSS R-TWT scheduler will operate can refer to the bandwidth on which the BSS AP operates, which is affected by the bandwidth on which the OBSS AP operates. In other words, information related to the bandwidth on which the corresponding OBSS R-TWT scheduler will operate can indicate information about the bandwidth on which a BSS AP operates that overlaps with the bandwidth on which the OBSS AP operates. For example, the subfield value associated with the information related to the bandwidth on which the corresponding OBSS R-TWT scheduler will operate can indicate 20MHz, 40MHz, 80MHz, 160MHz, 320MHz, or 640MHz.

[0349] For example, if the bandwidth operated by the OBSS AP is 80MHz and the bandwidth operated by the BSS AP is 160MHz, the overlapping bandwidth area between the bandwidth operated by the BSS AP and the bandwidth operated by the OBSS AP can be indicated by the TWT bandwidth subfield. In the example above, if the overlapping bandwidth between the bandwidth operated by the BSS AP and the bandwidth operated by the OBSS AP is 80MHz (or 40MHz or 20MHz), the TWT bandwidth subfield can be set to a value indicating 80MHz (or 40MHz or / and 20MHz).

[0350] Alternatively, for example, even if both the OBSS AP and the BSS AP operate on a bandwidth of 320MHz, if the secondary channels have different bandwidths (e.g., 160-1MHz or 160-2MHz from 320MHz within 6GHz, or an additional 20MHz from 40MHz within 2.4GHz), the TWT bandwidth subfield may indicate only the common bandwidth excluding non-overlapping bandwidths.

[0351] Based on the bandwidth indicated by the TWT bandwidth, information related to the channel on which the OBSS R-TWT scheduler will operate can be configured in bitmap format, where one bit indicates 20 MHz. That is, the length of the TWT channel field can vary depending on the value of the TWT bandwidth subfield. For example, if the TWT channel field has a length of one octet and the value of the TWT bandwidth subfield is set to indicate 40 MHz, then the TWT channel field can include two bits (e.g., 00, 01, 10, 11) of information about the channel on which the R-TWT scheduler will operate, and the remaining bits can be reserved.

[0352] Alternatively, when the OBSS R-TWT SP is indicated via the Broadcast TWT Recommendation field within the Broadcast TWT element, a specific element may be included on the Broadcast TWT element, and this specific element may include information / subfields related to the OBS R-TWT scheduling announced by the AP to the STA (e.g., including subfields for information on OBSS R-TWT scheduling or / and information indicating the existence of OBSS R-TWT scheduling information).

[0353] Method 4

[0354] Figure 18 When the value of the restricted TWT service information subfield in the broadcast TWT information subfield included in the beacon frame according to method 1 of embodiment 3-1 is set to 1, or when the scheduling information of the corresponding TWT element is indicated as OBSS R-TWT SP by the value of the TWT recommendation field in the broadcast TWT element according to method 2 of embodiment 3-1, the AP can send / announce information about the corresponding OBSS R-TWT SP in the following manner.

[0355] For example, such as Figure 18 As illustrated in (a), information regarding the OBSS R-TWT SP may include the BSS color of neighboring APs that have been assigned the OBSS R-TWT SP, the actual TWT persistence of the OBSS R-TWT SP, the TWT bandwidth, and the TWT channel information. In other words, regarding... Method 5 The information of the OBSS R-TWT SP illustrated in (a) can be included in the corresponding TWT element, and the AP can send the corresponding TWT element to the STA.

[0356] For example, if the restricted TWT service information subfield value in the broadcast TWT element included in the beacon frame is set to 1, then the broadcast TWT ID subfield can indicate that the information about the corresponding R-TWT SP is OBSS R-TWT SP information. The BSS color subfield can indicate the BSS color of the neighboring AP that assigned the corresponding OBSS R-TWT SP. The restricted TWT persistence subfield can indicate information related to the actual persistence of the corresponding OBSS R-TWT SP. The TWT bandwidth subfield can indicate information related to the bandwidth on which the corresponding OBSS R-TWT scheduler / SP will operate. The TWT channel subfield can indicate information related to the channel on which the corresponding OBSS R-TWT scheduler / SP will operate.

[0357] Method 5-1 The method for AP to send / announce OBSS R-TWT SP as described in Method 4 can be the same as the methods described below (Method 5-1 and Method 5-2).

[0358] Figure 18 When the value of the last broadcast parameter set subfield included in the request type field of the broadcast TWT parameter set is set to 1, an OBSS TWT parameter set can be added after the last broadcast TWT parameter set. The added OBSS TWT parameter set can be 10 octets or less in length, which is the length of the existing broadcast TWT parameter set.

[0359] For example, if one or more broadcast TWT IDs correspond to one OBSS R-TWT SP, information about the OBSS R-TWT SP corresponding to each broadcast TWT ID can be listed. As an example, such as... Method 5-2 As illustrated in (b), the OBSS TWT parameter set can be configured by listing information about the OBSS R-TWT SP corresponding to one or more broadcast TWT IDs. However, this is only one example, and an OBSS TWT parameter set can be configured based on the broadcast TWT ID.

[0360] Figure 18 The OBSS TWT element associated with OBSS R-TWT can be placed / located after the TWT element within the beacon frame. The OBSS TWT element can be placed as follows: Figure 18 The configuration is the same as in (c), but not limited to this.

[0361] For example, an OBSS TWT element may include a control field and an OBSS R-TWT SP information field. The control field may include an OBSS R-TWT SP subfield and a broadcast TWT ID subfield. The OBSS R-TWT SP subfield may indicate the total number of OBSS R-TWT SPs indicated by the TWT element. The broadcast TWT ID subfield may indicate the total number of broadcast TWT IDs included in the TWT element indicating an OBSS R-TWT SP. The corresponding total number of broadcast TWT IDs may indicate the number of times the broadcast TWT ID in the OBSS R-TWT SP information field is repeated. For example, the OBSS R-TWT SP information field may include... Figure 18 Additional information for the OBSS R-TWT SP illustrated in (a). As another example, if one or more broadcast TWT IDs correspond to an OBSSR-TWT SP, then as shown in (a) Embodiment 3-3 Configure the OBSS R-TWT SP information field in the same way as in (b).

[0362] Method 6

[0363] If the AP configures information about the R-TWT SP and information about the OBSS R-TWT SP in the beacon frame, the AP can add information about the OBSS R-TWT SP to the beacon frame in the manner described below.

[0364] Figure 18 If the last broadcast parameter set subfield in a given broadcast TWT parameter set has a value of 1, the AP may add an OBSS TWT parameter set field after the last broadcast TWT parameter set. The additional OBSS TWT parameter set may have a length of no more than 10 octets, which is the length of the existing broadcast TWT parameter set.

[0365] For example, if one or more broadcast TWT IDs correspond to OBSS R-TWT SPs, information about the OBSS R-TWT SPs corresponding to each broadcast TWT ID can be listed / arranged. Figure 18 The sequential arrangement shown in (a) can be as follows Method 7 Configure it in the same way as in (b). In this case, a set of parameters can be configured with broadcast TWTIDs as boundaries.

[0366] Figure 18 The OBSS TWT element described in reference method 5-2 can be positioned / placed after the TWT element in the beacon frame. The OBSS TWT element can be as follows: Figure 19 Configure it in the same way as in (c).

[0367] The following diagram illustrates the operation of AP / STA related to OBSS R-TWT SP.

[0368] Figure 19 The illustration shows the operation of an AP for notifying the OBSS R-TWT SP according to an embodiment of this disclosure, which may be applicable when an improved R-TWT is supported. Specifically, Figure 14 The operation is when STA (e.g., Figure 14 Operation when STA 1-2 and STA 2-4 exist in the overlapping position between the BSS of the AP (i.e., the AP to which the STA is associated) and the BSS of the neighboring AP. Figure 20 In the diagram, APs are shown as not being located in each other's BSS regions, but are not limited to this.

[0369] The AP can obtain information about the OBSS R-TWT SP directly or indirectly from a neighboring AP (S1910). The AP can determine whether the information about the OBSS R-TWT SP is included in the TWT element (S1920). If the information about the OBSS R-TWT SP is included in the TWT element, the AP can perform operations related to the information included in the TWT element. The AP can set the broadcast TWT ID corresponding to the OBSS R-TWT SP and the broadcast TWT ID corresponding to the R-TWT SP scheduled by the AP, such that they do not overlap.

[0370] For example, if the broadcast TWT ID set to correspond to the OBSS R-TWT SP and the broadcast TWT ID set to correspond to the R-TWT SP scheduled by the AP overlap, the AP can change the broadcast TWT ID corresponding to the OBSS R-TWT SP to a different value (S1940-1).

[0371] As another example, if the broadcast TWT ID set corresponding to the OBSS R-TWT SP and the broadcast TWT ID set corresponding to the R-TWT SP scheduled by the AP do not overlap, the AP can add additional information about the OBSS R-TWT SP (on the TWT element) according to the above embodiment (S1940-2). The AP can then announce the additional information about the OBSS R-TWT SP (S1950). Additionally, according to the above embodiment, membership requests from the STA for the OBSS R-TWT SP can be blocked.

[0372] Figure 20The illustration shows the operation of the AP notification for the overlapping silent interval of the OBSS R-TWT SP according to an embodiment of this disclosure. This operation can be applicable when supporting enhanced R-TWT. Specifically, Figure 14 The operation is when STA (e.g., Figure 14 Operation when STAs 1-2 and STAs 2-4 exist in an overlapping location between the BSS of an AP (i.e., the AP to which the STA is associated) and the BSS of a neighboring AP. Figure 20 In the diagram, APs are shown as not being located in each other's BSS regions, but are not limited to this.

[0373] In other words, Figure 21 This relates to a method for announcing the allocation information of a silent interval to a STA associated with an AP's BSS by allocating a silent interval that is set to repeat in the OBSS R-TWT SP.

[0374] The AP can obtain information about the OBSS R-TWT SP (S2010). The AP can determine whether to set / assign a silence interval that overlaps with the OBSS R-TWT SP (S2020). If a silence interval that overlaps with the OBSS R-TWT SP is set / assigned, the AP can include information related to the silence interval in the silence element and announce the silence element to the STA associated with the BSS (S2030).

[0375] As another example, if a silent interval overlapping with the OBSS R-TWT SP is not assigned, it may mean that the AP is not protecting the OBSS R-TWT SP through the silent interval. In this case, protection of the R-TWT SP may only be supported for STAs that support R-TWT and / or STAs that support the enhanced R-TWT SP.

[0376] Figure 21 This is a flowchart illustrating an embodiment of the present disclosure of an operation for an AP to perform R-TWT notification for each STA type. That is, Figure 22 This relates to a method for protecting OBSS R-TWT SPs based on information about R-TWT SPs notified by APs, according to capabilities supported by STAs.

[0377] The STA can be notified of information about the R-TWT SP from the associated BSS AP (S2110).

[0378] As an example of this disclosure, if the STA is a UHR STA that supports enhanced R-TWT (S2120-1), the STA can protect the OBSS R-TWT SP by stopping its TXOP before the start time of the OBSS R-TWT SP (S2130-1). Here, the STA can distinguish between the R-TWT SP scheduled by the AP and the OBSS R-TWT SP according to the above embodiment.

[0379] As another example of this disclosure, if the STA is an EHT / UHR STA that supports R-TWT (i.e., does not support enhanced R-TWT) (S2120-2), the STA cannot distinguish between R-TWT SPs and OBSS R-TWT SPs. Therefore, the STA can perform protection operations on all R-TWT SPs included in the manner notified from the AP (S2130-2).

[0380] As another example of this disclosure, if the STA is an EHT / Pre-EHT STA that does not support R-TWT (S2130-3), the STA may not be able to recognize the information announcement of the AP's R-TWT SP. Therefore, the STA can protect the OBSS R-TWT SP by a silent interval that overlaps with the OBSS R-TWT SP (S2130-3).

[0381] Figure 22 This is a diagram illustrating the PPDU transmission and reception process between a transmitting STA and a receiving STA according to an embodiment of the present disclosure. ​ Some of the steps shown may be omitted depending on the situation and / or settings. The transmitting device and the receiving STA can be an AP and / or a non-AP STA.

[0382] Sending the STA can obtain control information related to the aforementioned tone plan (or RU) (S105). The control information related to the tone plan may include the size and location of the RU, control information related to the RU, information about the frequency band included in the RU, information about the STA receiving the RU, etc.

[0383] The STA can configure / generate a PPDU based on the acquired control information (S110). Configuring / generating a PPDU can refer to configuring / generating each field of the PPDU. That is, the steps of configuring / generating a PPDU may include configuring the EHT-SIG-A / B / C fields, which include control information related to the tone plan.

[0384] In other words, the steps of configuring / generating a PPDU may include configuring a field that includes control information (e.g., an N-bitmap) indicating the size / location of the RU and / or configuring a field that includes an identifier (e.g., an AID) of the STA receiving the RU.

[0385] Additionally, the steps of configuring / generating PPDUs may include generating an STF / LTF sequence to be transmitted via a specific RU. This STF / LTF sequence can be generated based on a preset STF generation sequence / LTF generation sequence.

[0386] Additionally, the steps of configuring / generating PPDUs may include generating data fields (i.e., MPDUs) to be sent via a specific RU.

[0387] The sending STA can send the configured / generated PPDU to the receiving STA (S115).

[0388] Specifically, the transmitting STA can perform at least one of the following: CSD (Cyclic Shift Diversity), spatial mapping, IDFT (Inverse Discrete Fourier Transform) / IFFT (Inverse Fast Fourier Transform) operations, GI (Guard Interval) insertion operations, etc.

[0389] The receiving STA can decode the PPDU and obtain control information related to the tone plan (or RU) (S120).

[0390] Specifically, the receiving STA can decode the L-SIG and EHT-SIG of the PPDU based on the L-STF / LTF and obtain the information included in the L-SIG and EHT-SIG fields. Information about various tone schemes (i.e., RUs) of this disclosure can be included in the EHT-SIG (EHT-SIG-A / B / C, etc.), and the receiving STA can obtain information about tone schemes (i.e., RUs) through the EHT-SIG.

[0391] The receiving STA can decode the remainder of the PPDU based on information about the acquired tone plan (i.e., RU) (S125). For example, the receiving STA can decode the STF / LTF field of the PPDU based on information about the tone plan (i.e., RU). Additionally, the receiving STA can decode the data field of the PPDU based on information about the tone plan (i.e., RU) and obtain the MPDU included in the data field.

[0392] Additionally, the receiving STA can perform processing operations to send the decoded data to a higher layer (e.g., the MAC layer). Furthermore, if a signal indicating that data sent to a higher layer is being generated from that layer to the PHY layer is being generated, the receiving STA can perform subsequent operations.

[0393] Based on the data obtained through the above operations, the receiving STA can not only obtain R-TWT scheduling information, but also, in some cases, information about R-TWTs scheduled by neighboring APs. Therefore, the receiving STA can perform protection operations on the R-TWT SP.

[0394] The above embodiments combine the elements and features of this disclosure in a predetermined form. Unless otherwise expressly stated, each element or feature should be considered optional. Each element or feature can be implemented without combination with other elements or features. Furthermore, embodiments of this disclosure may include combinations of certain elements and / or features. The order of operations described in the embodiments of this disclosure may be changed. Some elements or features of one embodiment may be included in other embodiments, or may be replaced by corresponding elements or features of other embodiments. It is clear that embodiments may include combinations of claims where there is no explicit dependency in the claims, or may be included as new claims by amendment after the application.

[0395] It will be apparent to those skilled in the art that this disclosure may be practiced in other specific forms without departing from the essential characteristics of this disclosure. Therefore, the foregoing detailed description should not be construed as restrictive in every respect, but rather as illustrative. The scope of the invention should be determined by a reasonable interpretation of the appended claims, and all variations within the equivalent scope of this disclosure are included within the scope of the invention.

[0396] The scope of this disclosure includes software or machine-executable commands (e.g., operating systems, applications, firmware, programs, etc.) that operate in a device or computer according to methods of various embodiments, and non-transitory computer-readable media that store such software or commands and can be executed in a device or computer. Commands that can be used to program a processing system to perform the features described in this disclosure can be stored in a storage medium or a computer-readable storage medium, and the features described in this disclosure can be implemented using a computer program product including such a storage medium. The storage medium may include, but is not limited to, high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid-state storage devices, and may include non-volatile memory, such as one or more disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory may optionally include one or more storage devices located remote from the processor. Alternatively, the non-volatile memory devices in the memory may include non-transitory computer-readable storage media. The features described in this disclosure can be stored in any machine-readable medium to control the hardware of a processing system and can be integrated into software and / or firmware that allows the processing system to interact with other mechanisms using results from embodiments of this disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0397] [Industrial Applicability]

[0398] The method proposed in this disclosure is described primarily based on examples applied to IEEE 802.11-based systems, but it can also be applied to various WLAN or wireless communication systems other than IEEE 802.11-based systems.

Claims

1. A method performed by a station (STA) in a wireless local area network system, the method comprising: receiving, from a first access point (AP), a first frame including a first broadcast target wake up time (TWT) parameter set field and a second broadcast TWT parameter set field; and decoding the first frame, wherein a first broadcast TWT identifier (ID) and first information related to a first restricted TWT (R-TWT) service period (SP) scheduled by the first AP are included in the first broadcast TWT parameter set, and wherein a second TWT ID and second information related to a second R-TWT SP scheduled by the second AP are included in the second broadcast TWT parameter set.

2. The method of claim 1, wherein: a transmission opportunity (TXOP) of the STA is terminated by the STA before a start time of the second R-TWT SP.

3. The method of claim 1, wherein: a broadcast TWT information (info) subfield of the second broadcast TWT parameter set includes an R-TWT schedule information subfield, and the R-TWT schedule information subfield includes information indicating that a membership request by the STA related to the second R-TWT SP is not allowed.

4. The method of claim 1, wherein: a broadcast TWT information subfield of the second broadcast TWT parameter set includes an R-TWT schedule information subfield, and the R-TWT schedule information subfield includes information indicating that the second information is related to the second R-TWT SP scheduled by the second AP corresponding to a non-transmitted basic service set identifier (BSSID).

5. The method of claim 1, wherein: a value of a broadcast TWT persistence subfield included in the second broadcast parameter set field is set to a predefined minimum value.

6. The method of claim 1, wherein: the first frame includes a first TWT element, and a null data physical protocol data unit (NDP) paging indicator subfield and a responder power management (PM) subfield included in a control field of the first TWT element indicate that the second information is included in the first TWT element.

7. The method of claim 1, wherein: inclusion of the second information on the first TWT element is indicated by a TWT recommendation field included in the first TWT element of the first frame.

8. The method of claim 1, wherein: the first TWT element includes a plurality of parameter sets including the first broadcast parameter set and the second broadcast parameter set, and the second broadcast parameter set is a last broadcast parameter set among the plurality of broadcast parameter sets.

9. The method of claim 1, wherein: the second broadcast parameter set includes at least one of a BSS color of the second AP or a channel or bandwidth to be used by the second R-TWT SP.

10. The method of claim 1, wherein: the first frame includes a second TWT element and a third TWT element, the first broadcast parameter set is included in the second TWT element, and the second broadcast parameter set is included in the third TWT element. 11.The method of claim 1, wherein: the second R-TWT SP is protected by an overlapping quiet interval set by the first AP. 12.The method of claim 1, wherein: the first frame comprises a beacon frame. 13.The method of claim 1, wherein: the STA is associated with a BSS of the first AP. 14.A first station (STA) operating in a wireless LAN system, the first STA comprising: at least one transceiver; and at least one processor connected to the at least one transceiver, wherein the at least one processor is configured to: receive, through the at least one transceiver, a first frame including a first broadcast target wake time (TWT) parameter set field and a second broadcast TWT parameter set field from a first access point (AP); and decode the first frame, wherein a first broadcast TWT identifier (ID) and first information related to a first restricted TWT (R-TWT) service period (SP) scheduled by the first AP are included in the first broadcast TWT parameter set, and wherein a second TWT ID and second information related to a second R-TWT SP scheduled by the second AP are included in the second broadcast TWT parameter set. 15.A method performed by a first access point (AP) in a wireless LAN system, the method comprising: receiving, from a second AP, second information related to a second restricted target wake time (R-TWT) service period (SP); and transmitting, to a first station (STA), a first beacon frame including first information related to a first R-TWT SP and the second information, wherein the first beacon frame includes a first broadcast TWT parameter set field and a second broadcast TWT parameter set field, wherein the first broadcast TWT parameter set field includes the first information and a first broadcast TWT ID, and wherein the second broadcast TWT parameter set field includes the second information and a second broadcast TWT ID. 16.A first access point (AP) operating in a wireless LAN system, the first AP comprising: at least one transceiver; and at least one processor connected to the at least one transceiver, wherein the at least one processor is configured to: receive, through the at least one transceiver, second information related to a second restricted target wake time (R-TWT) service period (SP) from a second AP; and transmit, through the at least one transceiver, a first beacon frame including first information related to a first R-TWT SP and the second information to a first station (STA), wherein the first beacon frame includes a first broadcast TWT parameter set field and a second broadcast TWT parameter set field, wherein the first broadcast TWT parameter set field includes the first information and a first broadcast TWT ID, and wherein the second broadcast TWT parameter set field includes the second information and a second broadcast TWT ID. The second broadcast TWT parameter set field includes the second information and a second broadcast TWT ID.

17. A processing device configured to control a first station (STA) in a wireless LAN system, the processing device comprising: at least one processor; and at least one computer memory operably connectable to the at least one processor and storing instructions that, based on being executed by the at least one processor, perform operations comprising: receiving, from a first access point (AP), a first frame including a first broadcast target wake time (TWT) parameter set field and a second broadcast TWT parameter set field; and decoding the first frame, wherein a first broadcast TWT identifier (ID) and first information related to a first restricted TWT (R-TWT) service period (SP) scheduled by the first AP are included in the first broadcast TWT parameter set, and wherein a second TWT ID and second information related to a second R-TWT SP scheduled by the second AP are included in the second broadcast TWT parameter set.

18. At least one non-transitory computer-readable medium storing at least one instruction, wherein executable by at least one processor, to control a device in a wireless LAN system to: receive, from a first access point (AP), a first frame including a first broadcast target wake time (TWT) parameter set field and a second broadcast TWT parameter set field; and decode the first frame, wherein a first broadcast TWT identifier (ID) and first information related to a first restricted TWT (R-TWT) service period (SP) scheduled by the first AP are included in the first broadcast TWT parameter set, and wherein a second TWT ID and second information related to a second R-TWT SP scheduled by the second AP are included in the second broadcast TWT parameter set.

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