METHOD AND APPARATUS FOR TARGET WAKE TIME SERVICE PERIOD RE-SCHEDULE IN WIRELESS LAN SYSTEM

Abstract

A method and apparatus for rescheduling a target wake time service period in a wireless LAN system are disclosed. According to an embodiment of the present disclosure, a method performed by a station (STA) in a wireless LAN system may include establishing an agreement related to a restricted target wake time (r-TWT) and transmitting at least one frame including a TWT information field to one or more other STAs. Here, the TWT information field may include an r-TWT related subfield, an all TWT subfield, and a next TWT subfield, and rescheduling related information for an r-TWT service period (r-TWT SP) scheduled for the STA may be indicated based on the r-TWT related subfield, the all TWT subfield, and the next TWT subfield.

Description

[Technical field]

[0001] The present disclosure relates to target wake time (TWT) operations in Wireless Local Area Network (WLAN) systems, and more particularly to methods and apparatus related to rescheduling Restricted-TWT (R-TWT) service periods (SP) in next generation WLAN systems. [Background technology]

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

[0003] To provide a more improved wireless communication environment, improved technologies for EHT (Extremely High Throughput) are being discussed. For example, technologies for increased bandwidth, efficient use of multiple bands, MIMO (Multiple Input Multiple Output) supporting increased spatial streams, and multiple access point (AP) coordination are being studied, and in particular, various technologies for supporting traffic with low latency or real time characteristics are being studied. Furthermore, new technologies for supporting ultra high reliability (UHR), including improvements or extensions of EHT technology, are being discussed. Summary of the Invention [Problem to be solved by the invention]

[0004] The technical problem of the present disclosure is to provide a method and apparatus for transmitting latency-sensitive traffic in a wireless LAN system.

[0005] A further technical object of the present disclosure is to provide a method and apparatus related to suspension and / or resumption of a limited TWT service period (SP) in a wireless LAN system.

[0006] A further technical object of the present disclosure is to provide a method and apparatus for requesting or indicating an extension to an end point of a restricted TWT SP in a wireless LAN system.

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

[0008] A method performed by a station (STA) in a wireless LAN system according to an embodiment of the present disclosure may include establishing an agreement related to a restricted- target wake time (r-TWT) and transmitting at least one frame including a TWT information field to one or more other STAs, where the TWT information field may include an r-TWT related subfield, an all TWT subfield, and a next TWT subfield, and rescheduling related information for an r-TWT service period (r-TWT SP) scheduled for the STA may be indicated based on the r-TWT related subfield, the all TWT subfield, and the next TWT subfield. Effect of the Invention

[0009] According to the present disclosure, a method and apparatus can be provided for transmitting latency sensitive traffic in a wireless LAN system.

[0010] In accordance with the present disclosure, methods and apparatus may be provided relating to suspension and / or resumption of a limited TWT service period (SP) in a wireless LAN system.

[0011] According to the present disclosure, it is possible to provide a method and apparatus for requesting or indicating an extension to an end point of a restricted TWT SP in a wireless LAN system.

[0012] The effects obtained from the present disclosure are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the following description. [Brief description of the drawings]

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

[0014] [Figure 1] 1 is a block diagram illustrating a wireless communication device according to an embodiment of the present disclosure.

[0015] [Diagram 2] FIG. 1 is a diagram illustrating an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0016] [Diagram 3] FIG. 2 is a diagram illustrating a link setup process to which the present disclosure can be applied.

[0017] [Figure 4] FIG. 13 is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0018] [Diagram 5] 1 is a diagram for explaining a CSMA / CA base frame transmission operation to which the present disclosure can be applied.

[0019] [Figure 6] 1 is a diagram for explaining an example of a frame structure used in a wireless LAN system to which the present disclosure can be applied.

[0020] [Figure 7] FIG. 2 is a diagram illustrating an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0021] [Figure 8-10] FIG. 2 is a diagram for explaining an example of a resource unit of a wireless LAN system to which the present disclosure can be applied.

[0022] [Figure 11]FIG. 2 illustrates an exemplary structure of an HE-SIG-B field.

[0023] [Figure 12] FIG. 1 is a diagram for explaining a MU-MIMO scheme in which multiple users / STAs are assigned to one RU.

[0024] [Figure 13] A figure showing an example of a PPDU format to which the present disclosure can be applied.

[0025] [Figure 14] 1A to 1C are diagrams for explaining an example of individual TWT operation to which the present disclosure can be applied.

[0026] [Figure 15] FIG. 1 is a diagram for explaining an example of a broadcast TWT operation to which the present disclosure can be applied.

[0027] [Figure 16] FIG. 13 is a diagram for explaining an example of a TWT information field format.

[0028] [Figure 17] FIG. 13 is a diagram illustrating an example of a TWT information element format.

[0029] [Figure 18] A figure for explaining an example of an individual TWT parameter set field format.

[0030] [Figure 19] A diagram for explaining an example of a broadcast TWT parameter set field format.

[0031] [Figure 20] FIG. 1 is a diagram for explaining an example of limited TWT operation.

[0032] [Figure 21]FIG. 2 illustrates an example of an r-TWT related information frame according to the present disclosure.

[0033] [Figure 22] A diagram showing an example of restricted TWT operation based on an r-TWT information frame in accordance with the present disclosure.

[0034] [Figure 23] A diagram showing another example of restricted TWT operation based on an r-TWT information frame according to the present disclosure.

[0035] [Figure 24] A figure showing another example of an r-TWT related information frame relating to the present disclosure.

[0036] [Diagram 25] A figure showing yet another example of an r-TWT related information frame relating to the present disclosure.

[0037] [Figure 26] A figure showing yet another example of an r-TWT related information frame relating to the present disclosure.

[0038] [Figure 27] A figure showing yet another example of an r-TWT related information frame relating to the present disclosure.

[0039] [Figure 28] FIG. 1 illustrates an example of limited TWT operation taking into account an extended r-TWT SP according to the present disclosure.

[0040] [Figure 29] FIG. 13 illustrates another example of limited TWT operation taking into account an extended r-TWT SP according to the present disclosure.

[0041] [Diagram 30] FIG. 13 is a diagram for explaining the operation of a STA that supports rescheduling of an r-TWT SP according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed below together with the accompanying drawings is intended to describe exemplary embodiments of the present disclosure, and is not intended to show the only embodiment in which the present disclosure can be implemented. The detailed description below includes specific details to provide a complete understanding of the present disclosure. However, it is understood by those skilled in the art that the present disclosure can be implemented without such specific details.

[0043] In some cases, in order to avoid obscuring the concepts of the present disclosure, known structures and devices may be omitted or may be shown in the form of a block diagram focusing on the core functions of each structure and device.

[0044] In this disclosure, when a component is "coupled," "coupled," or "connected" to another component, this may include a direct connection as well as an indirect connection where there is another component between them. Also, in this disclosure, the term "comprise" or "have" specifies the presence of a referenced feature, step, operation, element, and / or component, but does not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0045] In this disclosure, the terms "first", "second", etc. are used only to distinguish one component from another component, and are not used to limit the components, and do not limit the order or importance of the components unless otherwise specified. Therefore, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

[0046] The terms used in this disclosure are for the purpose of describing particular embodiments and are not intended to limit the scope of the claims. As used in the description of the embodiments and the appended claims, the singular form is intended to include the plural form unless the context dictates otherwise. The term "and / or" used in this disclosure means that one of the associated listed items may be included, or any and all possible combinations of two or more of them. Also, in this disclosure, " / " between words has the same meaning as "and / or" unless otherwise specified.

[0047] The examples of the present disclosure may be applied to various wireless communication systems. For example, the examples of the present disclosure may be applied to a wireless LAN system. For example, the examples of the present disclosure may be applied to an IEEE 802.11a / g / n / ac / ax standard-based wireless LAN. Note that the examples of the present disclosure may be applied to a newly proposed IEEE 802.11be (or EHT) standard-based wireless LAN. The examples of the present disclosure may be applied to an IEEE 802.11be release-2 standard-based wireless LAN, which corresponds to a further improvement technology of the IEEE 802.11be release-1 standard. Furthermore, the examples of the present disclosure may be applied to a next-generation standard-based wireless LAN after IEEE 802.11be. Also, the examples of the present disclosure may be applied to a cellular wireless communication system. For example, the examples of the present disclosure may be applied to a cellular wireless communication system based on the Long Term Evolution (LTE) series technology and the New Radio (NR) series technology of the 3rd Generation Partnership Project (3GPP) standard.

[0048] Below, technical features to which the examples of the present disclosure can be applied are described.

[0049] FIG. 1 is a block diagram illustrating a wireless communication device according to an embodiment of the present disclosure.

[0050] The first device 100 and the second device 200 illustrated in Fig. 1 may be referred to as various terms such as a terminal, a wireless device, a wireless transmit receive unit (WTRU), a user equipment (UE), a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a mobile subscriber unit (MSS), a subscriber station (SS), an advanced mobile station (AMS), a wireless terminal (WT), or simply a user. In addition, the first device 100 and the second device 200 may be referred to as various terms such as an access point (AP), a base station (BS), a fixed station, a Node B, a base transceiver system (BTS), a network, an artificial intelligence (AI) system, a road side unit (RSU), a repeater, a router, a relay, a gateway, etc.

[0051] The devices 100 and 200 illustrated in FIG. 1 may also be referred to as stations (STAs). For example, the devices 100 and 200 illustrated in FIG. 1 may be referred to as various terms such as a transmitting device, a receiving device, a transmitting STA, and a receiving STA. For example, the STAs 110 and 200 may play the role of an AP (access point) or a non-AP. That is, in the present disclosure, the STAs 110 and 200 may have the function of an AP and / or a non-AP. When the STAs 110 and 200 have the AP function, they may simply be referred to as an AP, and when the STAs 110 and 200 have the non-AP function, they may simply be referred to as an STA. Also, in the present disclosure, an AP may be indicated as an AP STA.

[0052] 1, the first device 100 and the second device 200 may transmit and receive wireless signals using various wireless LAN technologies (e.g., IEEE 802.11 series). The first device 100 and the second device 200 may include interfaces to a medium access control (MAC) layer and a physical layer (PHY) in accordance with the provisions of the IEEE 802.11 standard.

[0053] In addition, the first device 100 and the second device 200 may further support various communication standards (e.g., 3GPP LTE series, 5G NR series standards, etc.) other than the WLAN technology. In addition, the device of the present disclosure may be embodied by various devices such as a mobile phone, a vehicle, a personal computer, an Augmented Reality (AR) device, and a Virtual Reality (VR) device. In addition, the STA of the present specification may support various communication services such as voice calls, image calls, data communications, autonomous driving, machine-type communication (MTC), machine-to-machine (M2M), device-to-device (D2D), and Internet-of-Things (IoT).

[0054] The first device 100 includes one or more processors 102 and one or more memories 104, and may further include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may be configured to control the memory 104 and / or the transceiver 106 to embody the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams in the present disclosure. For example, the processor 102 may process information in the memory 104 to generate a first information / signal, and then transmit a wireless signal including the first information / signal via the transceiver 106. The processor 102 may also receive a wireless signal including a second information / signal via the transceiver 106, and then store information obtained from signal processing of the second information / signal in the memory 104. The memory 104 may be coupled to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may store software code including instructions for executing some or all of the processes controlled by the processor 102 or for executing the descriptions, functions, procedures, suggestions, methods and / or operational flow diagrams in the present disclosure. Here, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., IEEE 802.11 series). The transceiver 106 may be coupled to the processor 102 and may transmit and / or receive wireless signals via one or more antennas 108. The transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be used interchangeably with a radio frequency (RF) unit. In the present disclosure, a device may also refer to a communication modem / circuit / chip.

[0055] The second device 200 may include one or more processors 202, one or more memories 204, and may further include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may be configured to control the memory 204 and / or the transceiver 206 to implement the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in the present disclosure. For example, the processor 202 may process information in the memory 204 to generate a third information / signal, and then transmit a wireless signal including the third information / signal via the transceiver 206. The processor 202 may also receive a wireless signal including a fourth information / signal via the transceiver 206, and then store information obtained from signal processing of the fourth information / signal in the memory 204. The memory 204 may be coupled to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may store software code including instructions for executing some or all of the processes controlled by the processor 202 or for executing the descriptions, functions, procedures, suggestions, methods and / or operational flow diagrams disclosed in the present disclosure. Here, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., IEEE 802.11 series). The transceiver 206 may be coupled to the processor 202 and may transmit and / or receive wireless signals via one or more antennas 208. The transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be used interchangeably with an RF unit. In the present disclosure, a device may also refer to a communication modem / circuit / chip.

[0056] The hardware elements of the devices 100, 200 are described in more detail below. Without being limited thereto, one or more protocol layers may be embodied by one or more processors 102, 202. For example, one or more processors 102, 202 may embody one or more layers (e.g., the same functional layers such as PHY, MAC). One or more processors 102, 202 may generate one or more Protocol Data Units (PDUs) and / or one or more Service Data Units (SDUs) according to the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams in the present disclosure. One or more processors 102, 202 may generate messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams in the present disclosure. The one or more processors 102, 202 can generate and provide signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, suggestions, and / or methods in this disclosure to the one or more transceivers 106, 206. The one or more processors 102, 202 can receive signals (e.g., baseband signals) from the one or more transceivers 106, 206 and obtain the PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams in this disclosure.

[0057] The one or more processors 102, 202 may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. The one or more processors 102, 202 may be embodied in hardware, firmware, software, or a combination thereof. As an example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) may be included in the one or more processors 102, 202. The descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in the present disclosure may be embodied using firmware or software, and the firmware or software may be embodied to include modules, procedures, functions, etc. Firmware or software configured to execute the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure may be included in one or more processors 102, 202 or stored in one or more memories 104, 204 and executed by one or more processors 102, 202. The descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure may be embodied in firmware or software in the form of code, instructions and / or collections of instructions.

[0058] One or more memories 104, 204 may be coupled to one or more processors 102, 202 and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. The one or more memories 104, 204 may be comprised of ROM, RAM, EPROM, flash memory, hard drives, registers, cache memory, computer readable storage media, and / or combinations thereof. The one or more memories 104, 204 may be located internal and / or external to the one or more processors 102, 202. Also, the one or more memories 104, 204 may be coupled to the one or more processors 102, 202 by various techniques, such as wired or wireless coupling.

[0059] The one or more transceivers 106, 206 may transmit user data, control information, wireless signals / channels, etc., as referred to in the methods and / or operational flow diagrams of the present disclosure, to one or more other devices. The one or more transceivers 106, 206 may receive user data, control information, wireless signals / channels, etc., as referred to in the descriptions, functions, procedures, suggestions, methods and / or operational flow diagrams of the present disclosure, from one or more other devices. For example, the one or more transceivers 106, 206 may be coupled to one or more processors 102, 202 and may transmit and receive wireless signals. For example, the one or more processors 102, 202 may control the one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other devices. Also, the one or more processors 102, 202 may control the one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. In addition, one or more transceivers 106, 206 may be coupled to one or more antennas 108, 208, and the one or more transceivers 106, 206 may be configured to transmit and receive user data, control information, radio signals / channels, etc., as described, functions, procedures, suggestions, methods, and / or operation flow diagrams disclosed in the present disclosure, via the one or more antennas 108, 208. In the present disclosure, the one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). The one or more transceivers 106, 206 may convert the received radio signals / channels, etc., from RF band signals to baseband signals for processing the received user data, control information, radio signals / channels, etc., using one or more processors 102, 202. The one or more transceivers 106, 206 may convert the user data, control information, radio signals / channels, etc., processed using one or more processors 102, 202, from baseband signals to RF band signals. To that end, one or more of the transceivers 106, 206 may include (analog) oscillators and / or filters.

[0060] For example, one of the STAs 100 and 200 can perform operations intended for an AP, and the other of the STAs 100 and 200 can perform operations intended for a non-AP STA. For example, the transceivers 106 and 206 in FIG. 1 can perform operations of transmitting and receiving signals (e.g., packets or PPDUs (Physical layer Protocol Data Units) conforming to IEEE 802.11a / b / g / n / ac / ax / be, etc.). In addition, in the present disclosure, operations of various STAs generating transmission and reception signals and performing data processing and calculations in advance for transmission and reception signals may be performed by the processors 102 and 202 in FIG. 1. For example, examples of operations for generating transmission / reception signals or performing data processing or calculations in advance for transmission / reception signals may include: 1) operations for determining / obtaining / configuring / calculating / decoding / encoding bit information of fields (SIG (signal), STF (short training field), LTF (long training field), Data, etc.) included in the PPDU; 2) operations for determining / configuring / obtaining time resources and frequency resources (e.g., subcarrier resources) used for fields (SIG, STF, LTF, Data, etc.) included in the PPDU; 3) operations for determining / configuring / obtaining specific sequences (e.g., pilot sequences, STF / LTF sequences, extra sequences applied to SIGs) used for fields (SIG, STF, LTF, Data, etc.) included in the PPDU; 4) power control operations and / or power saving operations applied to STAs; and 5) operations related to determining / obtaining / configuring / calculating / decoding / encoding an ACK signal, etc. In addition, various information (e.g., information regarding fields / subfields / control fields / parameters / power, etc.) used by various STAs in the following example for determining / obtaining / configuring / calculating / decoding / encoding transmitted / received signals may be stored in memory 104, 204 of FIG. 1.

[0061] Hereinafter, downlink (DL) refers to a link for communication from an AP STA to a non-AP STA, and downlink PPDUs / packets / signals, etc. may be transmitted and received through the downlink. In downlink communication, a transmitter may be part of an AP STA, and a receiver may be part of a non-AP STA. Uplink (UL) refers to a link for communication from a non-AP STA to an AP STA, and uplink PPDUs / packets / signals, etc. may be transmitted and received through the uplink. In uplink communication, a transmitter may be part of a non-AP STA, and a receiver may be part of an AP STA.

[0062] FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0063] The structure of a wireless LAN system may be composed of a number of components. A wireless LAN supporting STA mobility that is transparent to higher layers may be provided by the interaction of a number of components. A basic service set (BSS) corresponds to a basic building block of a wireless LAN. FIG. 2 illustrates an example in which 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). In FIG. 2, an ellipse representing a BSS may be understood to represent a coverage area in which STAs included in the BSS maintain communication. This area may be referred to as a basic service area (BSA). When a STA moves outside a BSA, it cannot directly communicate with other STAs in the BSA.

[0064] Without considering the DS shown in FIG. 2, the most basic type of BSS in a wireless LAN is an independent BSS (IBSS). For example, an IBSS may have a minimal form consisting of only two STAs. For example, assuming that other components are omitted, a BSS1 consisting of only STA1 and STA2, or a BSS2 consisting of only STA3 and STA4, may correspond to representative examples of an IBSS. Such a configuration is possible when the STAs can communicate directly without an AP. In addition, in such a form of wireless LAN, the IBSS is not configured in advance, but may be configured when the LAN requires it, and this may also be called an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity that performs a management function. That is, in an IBSS, the STAs are managed in a distributed manner. In an IBSS, all STAs may be mobile STAs, and connection to a distributed system (DS) is not allowed, forming a self-contained network.

[0065] The membership of STAs in a BSS may change dynamically as STAs come on and go, enter and leave the BSS domain, etc. To become a member of a BSS, a STA may join the BSS using a synchronization process. To access all the services of the BSS-based structure, a STA must be associated with the BSS. Such association may be configured dynamically and may include the use of a Distribution System Service (DSS).

[0066] In a wireless LAN, the direct STA-to-STA distance may be limited by the PHY performance. In some cases, such distance limits are sufficient, but in other cases, communication between STAs at greater distances may be required. A distributed system (DS) may be configured to support extended coverage.

[0067] DS means a structure in which BSSs are interconnected. Specifically, as shown in FIG. 2, a BSS may exist as a component of an expanded form of a network composed of multiple BSSs. DS is a logical concept and may be specified by the characteristics of a distributed system medium (DSM). In this regard, a wireless medium (WM) and a DSM may be logically distinguished. Each logical medium is used for different purposes and by different components. These media are not limited to being the same or different. In this way, the flexibility of a WLAN structure (DS structure or other network structure) can be explained in that multiple media are logically different from each other. That is, the WLAN structure may be embodied in various ways, and the WLAN structure may be independently specified according to the physical characteristics of each embodiment.

[0068] The DS can support mobile devices by providing seamless integration of multiple BSSs and logical services necessary to address destinations. The DS may also include a portal component that acts as a bridge between the wireless LAN and other networks (e.g., IEEE 802.X).

[0069] An AP means an entity that allows associated non-AP STAs to access a DS through a WM and also has the functionality of an STA. Data can be moved between a BSS and a DS via an AP. For example, STA2 and STA3 shown in FIG. 2 provide a function that allows associated non-AP STAs (STA1 and STA4) to access a DS while having the functionality of an STA. In addition, since all APs basically correspond to STAs, all APs are addressable entities. The address used by an AP for communication on a WM and the address used by an AP for communication on a DSM do not necessarily have to be the same. A BSS consisting of an AP and one or more STAs can be called an infrastructure BSS.

[0070] Data sent from one of the STAs coupled to the AP to the STA address of the AP is always received on an uncontrolled port and may be processed by the IEEE 802.1X port access entity, and the transmitted data (or frame) may be delivered to the DS if the controlled port is authenticated.

[0071] In the above-mentioned DS structure, an Extended Service Set (ESS) may be configured to provide wider coverage.

[0072] An ESS is a network of arbitrary size and complexity composed of a DS and a BSS. An ESS may be a collection of BSSs connected to one DS. However, an ESS does not include a DS. An ESS network is characterized by appearing as an IBSS at the Logical Link Control (LLC) layer. STAs included in an ESS can communicate with each other, and mobile STAs can move from one BSS to another (within the same ESS) transparently to the LLC. APs included in one ESS may have the same service set identification (SSID). SSID is distinguished from BSSID, which is an identifier of a BSS.

[0073] In a wireless LAN system, no assumptions are made regarding the relative physical locations of the BSSs, and any of the following configurations are possible: The BSSs may overlap, which is a configuration commonly used to provide continuous coverage; The BSSs may not be physically connected, and there is no logical limit to the distance between the BSSs; The BSSs may be physically located in the same location, which may be used to provide redundancy; One (or more) IBSS or ESS network may physically exist in the same space as one (or more) ESS network. This may be the case when an ad-hoc network operates in the location where the 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.

[0074] FIG. 3 is a diagram for explaining a link setup process to which the present disclosure can be applied.

[0075] In order for an STA to set up a link to a network and transmit and receive data, it must first discover the network, perform authentication, establish an association, and perform authentication procedures for security. The link setup process can be called a session initiation process or a session setup process. In addition, the discovery, authentication, association, and security setting processes of the link setup process can be collectively called an association process.

[0076] In step S310, the STA may perform a network discovery operation. The network discovery operation may include a scanning operation of the STA. That is, in order for the STA to access a network, the STA must search for a network that it can join. Before joining a wireless network, the STA must identify a compatible network, and the process of identifying networks that exist in a particular area is called scanning.

[0077] There are two types of scanning methods: active scanning and passive scanning. FIG. 3 illustrates a network discovery operation including an active scanning process. In active scanning, a scanning STA transmits a probe request frame to search for APs in the vicinity while changing channels, and waits for a response to the probe request frame. A responder transmits a probe response frame to the STA that transmitted the probe request frame as a response to the probe request frame. Here, the responder may be the STA that transmitted a beacon frame last in the BSS of the channel being scanned. In the BSS, the AP transmits a beacon frame, so the AP becomes the responder, and in the IBSS, the STAs in the IBSS transmit beacon frames alternately, so the responder is not constant. For example, a STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 can store the BSS-related information contained in the received probe response frame and move to the next channel (e.g., channel 2) and perform scanning in the same manner (i.e., sending and receiving a probe request / response on channel 2).

[0078] Although not shown in FIG. 3, the scanning operation may be performed in a passive scanning manner. In passive scanning, the scanning STA waits for a beacon frame while changing channels. A beacon frame is one of the management frames defined in IEEE 802.11, and is periodically transmitted to inform the existence of a wireless network and to allow the scanning STA to search for and join the wireless network. In a BSS, an AP is responsible for periodically transmitting a beacon frame, and in an IBSS, STAs in the IBSS transmit beacon frames in turn. When a scanning STA receives a beacon frame, it stores information about the BSS included in the beacon frame and records beacon frame information on each channel while moving to another channel. A STA that receives a beacon frame stores information about the BSS included in the received beacon frame, moves to the next channel, and can perform scanning on the next channel in the same manner. Comparing active scanning with passive scanning, active scanning has an advantage of having a smaller delay and power consumption than passive scanning.

[0079] After the STA discovers the network, an authentication process may be performed in step S320. This authentication process may be called a first authentication process in order to clearly distinguish it from the security setup operation in step S340 described below.

[0080] The authentication process includes a process in which the STA transmits an authentication request frame to the AP, and in response, the AP transmits an authentication response frame to the STA. The authentication frame used in the authentication request / response corresponds to a management frame.

[0081] The authentication frame may include information regarding an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a Robust Security Network (RSN), a Finite Cyclic Group, etc. These are only examples of information that may be included in an authentication request / response frame, and other information may be substituted or additional information may be included.

[0082] The STA can send an authentication request frame to the AP. The AP can determine whether to allow authentication for the STA based on the information contained in the received authentication request frame. The AP can provide the result of the authentication process to the STA using an authentication response frame.

[0083] After the STA is successfully authenticated, an association process may be performed in step S330. The association process includes the STA sending an association request frame to the AP, and in response, the AP sending an association response frame to the STA.

[0084] For example, the association request frame may include information on various capabilities, a beacon listen interval, a service set identifier (SSID), supported rates, supported channels, an RSN, a mobility domain, supported operating classes, a Traffic Indication Map Broadcast request, interworking service capabilities, etc. For example, the association response frame may include information on various capabilities, a status code, an association ID (AID), supported rates, an Enhanced Distributed Channel Access (EDCA) parameter set, a Received Channel Power Indicator (RCPI), a Received Signal to Noise Indicator (RSNI), a mobility domain, a timeout interval (e.g., an association comeback time), overlapping BSS scan parameters, a TIM broadcast response, a Quality of Service (QoS) map, etc. This corresponds to an example of some of the information that may be included in the association request / response frame, and other information may be substituted or additional information may be included.

[0085] After the STA is successfully connected to the network, a security setup process may be performed in step S340. The security setup process in step S340 may be referred to as an authentication process using a Robust Security Network Association (RSNA) request / response, the authentication process in step S320 may be referred to as a first authentication process, and the security setup process in step S340 may simply be referred to as an authentication process.

[0086] The security setup process of step S340 may include a process of performing a private key setup using, for example, 4-way handshaking using an Extensible Authentication Protocol over LAN (EAPOL) frame, and may be performed by a security method not defined in the IEEE 802.11 standard.

[0087] FIG. 4 is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0088] In wireless LAN systems, the basic access mechanism of MAC (Medium Access Control) is the Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) mechanism. The CSMA / CA mechanism is also called the Distributed Coordination Function (DCF) of the IEEE 802.11 MAC, and basically adopts a "listen before talk" access mechanism. According to this type of access mechanism, the AP and / or STA may perform a Clear Channel Assessment (CCA) to sense the wireless channel or medium at a predetermined time interval (e.g., DCF Inter-Frame Space (DIFS)) prior to starting transmission. If the medium is determined to be in an idle status as a result of the sensing, the AP and / or STA may start transmitting a frame through the medium. On the other hand, if the medium is detected to be occupied or busy, the AP and / or STA may not start its own transmission, but may set a delay period (e.g., a random backoff period) for medium access and wait before attempting to transmit a frame. By applying the random backoff period, multiple STAs are expected to wait for different times before attempting to transmit a frame, thereby minimizing collisions.

[0089] The IEEE 802.11 MAC protocol also provides a Hybrid Coordination Function (HCF). The HCF is based on the DCF and the Point Coordination Function (PCF). The PCF is a polling-based synchronous access method that periodically polls so that all receiving APs and / or STAs can receive data frames. The HCF also includes Enhanced Distributed Channel Access (EDCA) and HCF Controlled Channel Access (HCCA). EDCA refers to a contention-based access method for a provider to provide data frames to multiple users, and HCCA refers to a non-contention-based channel access method using a polling mechanism. The HCF also includes a medium access mechanism for improving the Quality of Service (QoS) of a wireless LAN, and can transmit QoS data in both a contention period (CP) and a contention-free period (CFP).

[0090] An operation based on the random backoff period will be described with reference to FIG. 4. When an occupied / busy medium is changed to an idle state, multiple STAs can attempt to transmit data (or frames). As a method for minimizing collisions, each STA can select a random backoff count and attempt transmission after waiting for a slot time corresponding to the random backoff count. The random backoff count has a pseudo-random integer value and may be determined to any one of values ​​in the range of 0 to CW. Here, CW is a contention window parameter value. The CW parameter is given an initial value of CWmin, but can take a value twice as large in the case of a transmission failure (e.g., when an ACK for a transmitted frame cannot be received). When the CW parameter value becomes CWmax, data transmission can be attempted while maintaining the CWmax value until data transmission is successful, and when data transmission is successful, the CW parameter is reset to the CWmin value. The CW, CWmin, and CWmax values ​​are determined to be two times as large as the CWmin value. n It is preferably set to -1 (n=0,1,2,...).

[0091] When the random backoff process begins, the STA continuously monitors the medium while counting down the backoff slots according to the determined backoff count value. If the medium is monitored as occupied, the STA stops the countdown and waits, and resumes the remaining countdown when the medium becomes idle.

[0092] In the example of FIG. 4, when a packet to be transmitted arrives at the MAC of STA3, STA3 confirms that the medium is idle for DIFS and can immediately transmit a frame. The remaining STAs monitor the medium for occupied / busy state and wait. In the meantime, data to be transmitted may also occur in each of STA1, STA2, and STA5. When the medium is monitored as idle, each STA can count down the backoff slots according to the random backoff count value selected by each STA after waiting for DIFS. Assume that STA2 selects the smallest backoff count value and STA1 selects the largest backoff count value. That is, the example shows a case where the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1 at the time when STA2 finishes the backoff count and starts frame transmission. STA1 and STA5 stop counting down for a while and wait while STA2 occupies the medium. When STA2 ends its occupation and the medium becomes idle again, STA1 and STA5 wait for DIFS and then resume the backoff count that they had stopped. That is, after counting down the remaining backoff slots by the remaining backoff time, STA5 can start frame transmission. Since the remaining backoff time of STA5 is shorter than that of STA1, STA5 starts frame transmission. While STA2 occupies the medium, STA4 may also have data to transmit. From STA4's perspective, when the medium becomes idle, it waits for DIFS and then counts down the random backoff count value it has selected, and can start frame transmission. The example of FIG. 4 shows a case where the remaining backoff time of STA5 coincidentally matches the random backoff count value of STA4, in which case a collision may occur between STA4 and STA5. When a collision occurs, neither STA4 nor STA5 can receive an ACK, and data transmission will fail. In this case, STA4 and STA5 can select a random backoff count value and count down after doubling the CW value.STA1 waits while the medium is occupied by transmissions from STA4 and STA5, but when the medium becomes idle, it waits for DIFS and can begin frame transmission after the remaining backoff time has elapsed.

[0093] As shown in the example of FIG. 4, a data frame is a frame used for transmitting data to be forwarded to a higher layer, and may be transmitted after a backoff performed after a DIFS has elapsed since the medium became idle. Furthermore, a management frame is a frame used for exchanging management information that is not forwarded to a higher layer, and is transmitted after a backoff performed after an IFS such as a DIFS or a PIFS (Point coordination function IFS). Subtype frames of the management frame include a beacon, an association request / response, a re-association request / response, a probe request / response, and an authentication request / response. A control frame is a frame used to control access to a medium. Subtype frames of control frames include Request-To-Send (RTS), Clear-To-Send (CTS), Acknowledgment (ACK), Power Save-Poll (PS-Poll), BlockAck, BlockACKReq, null data packet announcement, and Trigger. If a control frame is not a response frame of a previous frame, it is transmitted after a backoff that is performed after a DIFS has elapsed, and if a control frame is a response frame of a previous frame, it is transmitted without a backoff after a short IFS (SIFS). The type and subtype of a frame may be identified by a type field and a subtype field in a frame control (FC) field.

[0094] A Quality of Service (QoS) STA can transmit a frame after backing off after the arbitration IFS (AIFS) for the access category (AC) to which the frame belongs, i.e., AIFS[i] (where i is a value determined by the AC), where the frame can be a data frame, a management frame, or a control frame that is not a response frame.

[0095] FIG. 5 is a diagram for explaining a CSMA / CA base frame transmission operation to which the present disclosure can be applied.

[0096] As described above, the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing, in which the STA directly senses the medium. Virtual carrier sensing is intended to compensate for problems that may occur in medium access, such as the hidden node problem. For virtual carrier sensing, the MAC of the STA can use the NAV (Network Allocation Vector). The NAV is a value that indicates to other STAs the time remaining until the medium becomes available to the STA that is currently using or has the authority to use the medium. Therefore, the value set as the NAV corresponds to the period during which the STA that transmits the frame is scheduled to use the medium, and the STA that receives the NAV value is prohibited from accessing the medium during that period. For example, the NAV may be set based on the value of the "duration" field in the MAC header of the frame.

[0097] In the example of FIG. 5, assume that STA1 is attempting to transmit data to STA2, and that STA3 is in a position where it may overhear some or all of the frames transmitted between STA1 and STA2.

[0098] In order to reduce the possibility of collision of transmissions of multiple STAs in a CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames may be applied. In the example of FIG. 5, while STA1 is transmitting, the carrier sensing of STA3 may determine that the medium is idle. That is, STA1 may correspond to a hidden node to STA3. Or, in the example of FIG. 5, while STA2 is transmitting, the carrier sensing of STA3 may determine that the medium is idle. That is, STA2 may correspond to a hidden node to STA3. By exchanging RTS / CTS frames before data transmission / reception between STA1 and STA2, a STA outside the transmission range of either STA1 or STA2, or a STA outside the carrier sensing range for transmissions from STA1 or STA3, may not attempt to occupy the channel during data transmission / reception between STA1 and STA2.

[0099] Specifically, STA1 can determine whether the channel is occupied or not using carrier sensing. In terms of physical carrier sensing, STA1 can determine the channel occupancy idle state based on the energy magnitude or signal correlation detected from the channel. In addition, in terms of virtual carrier sensing, STA1 can determine the channel occupancy state using a network allocation vector (NAV) timer.

[0100] When the channel is idle in DIFS, STA1 can send an RTS frame to STA2 after backing off. When STA2 receives the RTS frame, it can send a CTS frame, which is a response to the RTS frame, to STA1 after SIFS.

[0101] If STA3 cannot overhear a CTS frame from STA2 but can overhear an RTS frame from STA1, STA3 can set a NAV timer for a frame transmission period (e.g., SIFS+CTS frame+SIFS+data frame+SIFS+ACK frame) that will be transmitted subsequently using duration information included in the RTS frame. Alternatively, if STA3 cannot overhear an RTS frame from STA1 but can overhear a CTS frame from STA2, STA3 can set a NAV timer for a frame transmission period (e.g., SIFS+data frame+SIFS+ACK frame) that will be transmitted subsequently using duration information included in the CTS frame. That is, if STA3 can overhear one or more of the RTS or CTS frames from at least one of STA1 and STA2, it can set the NAV based thereon. If STA3 receives a new frame before the NAV timer expires, it can update the NAV timer using the duration information included in the new frame. STA3 will not attempt channel access until the NAV timer expires.

[0102] When STA1 receives a CTS frame from STA2, it can transmit a data frame to STA2 after SIFS from the point when reception of the CTS frame is completed. When STA2 successfully receives a data frame, it can transmit an ACK frame, which is a response to the data frame, to STA1 after SIFS. When the NAV timer expires, STA3 can determine whether the channel is in use using carrier sensing. When STA3 determines that the channel is not in use by another terminal during the DIFS period after the expiration of the NAV timer, it can attempt channel access after the contention window (CW) with random backoff has passed.

[0103] FIG. 6 is a diagram for explaining an example of a frame structure used in a wireless LAN system to which the present disclosure can be applied.

[0104] The PHY layer can prepare an MPDU (MAC PDU) to be transmitted according to an instruction or primitive (meaning a set of instructions or parameters) from the MAC layer. For example, when a command requesting the PHY layer to start transmission is received from the MAC layer, the PHY layer switches to a transmission mode and transmits information (e.g., data) provided by the MAC layer in the form of a frame. Also, when the PHY layer detects a valid preamble of a received frame, it monitors the preamble header and sends a command to the MAC layer to inform the PHY layer of the start of reception.

[0105] Thus, information transmission / reception in a wireless LAN system is performed in the form of frames, for which a PHY layer protocol data unit (PPDU) frame format is defined.

[0106] A basic PPDU frame may include a Short Training Field (STF), a Long Training Field (LTF), a Signal (SIG) field, and a Data field. The most basic (e.g., non-High Throughput (HT)) PPDU frame format may be composed of only Legacy-STF (L-STF), Legacy-LTF (L-LTF), a SIG field, and a Data field. Depending on the type of PPDU frame format (e.g., HT-mixed format PPDU, HT-greenfield format PPDU, Very High Throughput (VHT) PPDU, etc.), additional (or other types) STF, LTF, and SIG fields may be included between the SIG field and the Data field (this will be described later with reference to FIG. 7).

[0107] The STF is a signal for signal detection, AGC (Automatic Gain Control), diversity selection, precise time synchronization, etc., and the LTF is a signal for channel estimation, frequency error estimation, etc. The STF and LTF can be said to be signals for synchronization and channel estimation of the OFDM physical layer.

[0108] The SIG field may include a RATE field and a LENGTH field, etc. The RATE field may include information about the modulation and coding rate of the data. The LENGTH field may include information about the length of the data. Furthermore, the SIG field may include parity bits, SIG TAIL bits, etc.

[0109] The data field may include a SERVICE field, a PSDU (Physical layer Service Data Unit), PPDU TAIL bits, and, if necessary, padding bits. Some bits of the SERVICE field may be used for synchronization of a descrambler at the receiving end. The PSDU corresponds to a MAC PDU defined in the MAC layer and may include data generated / used by a higher layer. The PPDU TAIL bits may be used to return the encoder to a 0 state. The padding bits may be used to adjust the length of the data field to a predetermined unit.

[0110] A MAC PDU is defined by various MAC frame formats, and a basic MAC frame consists of a MAC header, a frame body, and a Frame Check Sequence (FCS). A MAC frame is composed of a MAC PDU and may be transmitted / received by a PSDU in the data portion of the PPDU frame format.

[0111] The MAC header includes a Frame Control field, a Duration / ID field, an Address field, etc. The Frame Control field may include control information required for frame transmission / reception. The Duration / ID field may be set to the time for transmitting the frame, etc. For specific contents of the Sequence Control, QoS Control, and HT Control subfields of the MAC header, refer to the IEEE 802.11 standard document.

[0112] The null data packet (NDP) frame format refers to a frame format that does not include a data packet. That is, the NDP frame refers to a frame format that includes a PLCP (physical layer convergence procedure) header portion (i.e., STF, LTF, and SIG fields) in a general PPDU frame format, but does not include the remaining portion (i.e., data field). The NDP frame can also be referred to as a short frame format.

[0113] FIG. 7 is a diagram illustrating an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0114] Various forms of PPDU 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 Data fields. The basic PPDU format can also be called non-HT PPDU format.

[0115] The HT PPDU format (IEEE 802.11n) further includes HT-SIG, HT-STF, and HT-LFT(s) fields in the basic PPDU format. The HT PPDU format shown in Fig. 7 may be referred to as an HT-mixed format. An HT-greenfield format PPDU may be further defined, which corresponds to a format that does not include L-STF, L-LTF, and L-SIG, but is composed of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a Data field (not shown).

[0116] An example of a VHT PPDU format (IEEE 802.11ac) further includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in addition to the basic PPDU format.

[0117] An example of the HE PPDU format (IEEE 802.11ax) further includes a Repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), and Packet Extension (PE) field in the basic PPDU format. Depending on the detailed example of the HE PPDU format, some fields may be excluded or their length may change. For example, the HE-SIG-B field is included in the HE PPDU format for multiple users (MU), and the HE-SIG-B is not included in the HE PPDU format for single users (SU). In addition, the HE trigger-based (TB) PPDU format does not include HE-SIG-B, and the length of the HE-STF field may change to 8us. The HE Extended Range (ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may change to 16us.

[0118] 8 to 10 are diagrams illustrating examples of resource units in a wireless LAN system to which the present disclosure can be applied.

[0119] With reference to Fig. 8 to Fig. 10, a resource unit (RU) defined in a wireless LAN system will be described. An RU may include a plurality of subcarriers (or tones). An RU may be used when transmitting signals to a plurality of STAs based on an OFDMA technique. An RU may also be defined when transmitting a signal to one STA. An RU may be used for the STF, LTF, data field, etc. of a PPDU.

[0120] 8 to 10, RUs corresponding to different numbers of tones (i.e., subcarriers) may be used to configure some fields of 20 MHz, 40 MHz, or 80 MHz X-PPDU (X is HE, EHT, etc.). For example, resources may be allocated in units of RUs shown for the X-STF, X-LTF, and Data fields.

[0121] FIG. 8 is a diagram illustrating an exemplary arrangement of resource units (RUs) used on a 20 MHz band.

[0122] As shown at the top of FIG. 8, 26 units (i.e., units corresponding to 26 tones) may be allocated. Six tones may be used as a guard band in the leftmost band of the 20 MHz band, and five tones may be used as a guard band in the rightmost band of the 20 MHz band. Seven DC tones may be inserted into the center band, i.e., the DC band, and there may be 26 units corresponding to 13 tones on each side of the DC band. 26 units, 52 units, or 106 units may be allocated to other bands. Each unit may be allocated for a STA or a user.

[0123] The RU arrangement in Figure 8 can be utilized not only for multiple user (MU) situations, but also for single user (SU) situations, in which case one 242 unit can be used as shown at the bottom of Figure 8. In this case, three DC tones may be inserted.

[0124] In the example of FIG. 8, RUs of various sizes, i.e., 26-RU, 52-RU, 106-RU, 242-RU, etc., are illustrated, but the specific size of such RUs may be reduced or expanded. Therefore, the specific size of each RU (i.e., the number of corresponding tones) is not limited in the present disclosure and is merely exemplary. Also, in the present disclosure, within a given bandwidth (e.g., 20, 40, 80, 160, 320 MHz, ...), the number of RUs may vary depending on the size of the RU. The examples of FIG. 9 and / or FIG. 10 described below are the same as the examples of FIG. 8 in that the size and / or number of RUs may be changed.

[0125] FIG. 9 is a diagram illustrating an example arrangement of resource units (RUs) used on a 40 MHz band.

[0126] Just as various sizes of RUs are used in the example of Figure 8, 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, etc. may be used in the example of Figure 9. In addition, five DC tones may be inserted at the center frequency, 12 tones may be used as a guard band in the leftmost band of the 40 MHz band, and 11 tones may be used as a guard band in the rightmost band of the 40 MHz band.

[0127] Also, as shown in the figure, when used for a single user, 484-RU may be used.

[0128] FIG. 10 is a diagram illustrating an example arrangement of resource units (RUs) used on an 80 MHz band.

[0129] As various sizes of RUs are used in the examples of Figures 8 and 9, 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, 996-RU, etc. may be used in the example of Figure 10. In addition, in the 80 MHz PPDU, the RU arrangements of the HE PPDU and the EHT PPDU may differ from each other, and the example of Figure 10 shows an example of the RU arrangement for the 80 MHz EHT PPDU. In the example of Figure 10, the HE PPDU and the EHT PPDU are the same in that 12 tones are used as a guard band in the leftmost band of the 80 MHz band and 11 tones are used as a guard band in the rightmost band of the 80 MHz band. In the HE PPDU, 7 DC tones are inserted into the DC band, and there is one 26-RU corresponding to 13 tones on each side of the DC band. In the EHT PPDU, 23 DC tones are inserted into the DC band, and there is one 26-RU on the left and right side of the DC band. In the HE PPDU, there is one null subcarrier between the 242-RUs that are not in the center band, but there are five null subcarriers in the EHT PPDU. In the HE PPDU, one 484-RU does not contain a null subcarrier, but in the EHT PPDU, one 484-RU contains five null subcarriers.

[0130] Also, as shown in the figure, when used for a single user, 996-RU may be used, and in this case, five DC tones are inserted, which is common to both the HE PPDU and the EHT PPDU.

[0131] An EHT PPDU of 160 MHz or more may be configured with multiple 80 MHz sub-blocks in Fig. 10. The RU allocation for each 80 MHz sub-block may be the same as the RU allocation of the 80 MHz EHT PPDU in Fig. 10. When the 80 MHz sub-blocks of the 160 MHz or 320 MHz EHT PPDU are not punctured and the entire 80 MHz sub-block is used as a part of an RU or MRU (Multiple RU), the 80 MHz sub-block can use 996-RU in Fig. 10.

[0132] Here, the MRU corresponds to a group of subcarriers (or tones) composed of multiple RUs, and the multiple RUs constituting the MRU may be RUs of the same size or may be RUs of different sizes. For example, a single MRU may be defined as 52+26-tones, 106+26-tones, 484+242-tones, 996+484-tones, 996+484+242-tones, 2×996+484-tones, 3×996-tones, or 3×996+484-tones. Here, the multiple RUs constituting one MRU may correspond to RUs of small size (e.g., 26, 52, 106) or RUs of large size (e.g., 242, 484, 996, etc.). That is, one MRU including RUs of small size and RUs of large size may not be set / defined. In addition, the multiple RUs constituting one MRU may be contiguous or not contiguous in the frequency domain.

[0133] If an 80 MHz sub-block contains RUs with fewer than 996 tones or if portions of the 80 MHz sub-block are punctured, the 80 MHz sub-block may use an RU placement that excludes the 996-tone RU.

[0134] The RU of the present disclosure may be used for uplink (UL) and / or downlink (DL) communication. For example, when trigger-based UL-MU communication is performed, a STA (e.g., an AP) that transmits a trigger may use trigger information (e.g., a trigger frame or TRS (triggered response scheduling)) to assign a first RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to a first STA and a second RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to a second STA. Then, the first STA may transmit a first trigger-based (TB) PPDU based on the first RU, and the second STA may transmit a second TB PPDU based on the second RU. The first and second TB PPDUs may be transmitted to the AP in the same time interval.

[0135] For example, when a DL MU PPDU is configured, a STA (e.g., an AP) transmitting the DL MU PPDU can assign a first RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to a first STA and a second RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to a second STA. That is, the transmitting STA (e.g., an AP) can transmit the HE-STF, HE-LTF, and Data fields for the first STA using the first RU and can transmit the HE-STF, HE-LTF, and Data fields for the second STA using the second RU in one MU PPDU.

[0136] Information regarding the location of the RU may be signaled in the HE-SIG-B in HE PPDU format.

[0137] FIG. 11 illustrates an example structure of an HE-SIG-B field.

[0138] As shown in the figure, the HE-SIG-B fields may include common fields and user-specific fields. If HE-SIG-B compression is applied (e.g., full bandwidth MU-MIMO transmission), the common fields may not be included in the HE-SIG-B and the HE-SIG-B content channel may include only user-specific fields. If HE-SIG-B compression is not applied, the common fields may be included in the HE-SIG-B.

[0139] The common field may include information regarding RU allocation (e.g., RU assignment, RUs allocated for MU-MIMO, number of MU-MIMO users (STAs), etc.).

[0140] The common field may include N*8 RU allocation subfields, where N is the number of subfields, and may have values ​​of N=1 for 20 or 40 MHz MU PPDU, N=2 for 80 MHz MU PPDU, N=4 for 160 MHz or 80+80 MHz MU PPDU, .... One 8-bit RU allocation subfield may indicate the size (26, 52, 106, etc.) and frequency location (or RU index) of the RUs included in the 20 MHz band.

[0141] For example, if the value of the 8-bit RU allocation subfield is 00000000, nine 26-RUs are arranged in order from the leftmost to the rightmost in the example of Figure 8, if the value is 00000001, seven 26-RUs and one 52-RU are arranged in order from the leftmost to the rightmost, and if the value is 00000010, five 26-RUs, one 52-RU, and two 26-RUs are arranged in order from the leftmost to the rightmost.

[0142] As an additional example, if the value of the 8-bit RU allocation subfield is 01000y2y1y0, it can indicate that one 106-RU and five 26-RUs are arranged in sequence from the leftmost to the rightmost in the example of FIG. 8. In this case, multiple users / STAs may be allocated to the 106-RU in the MU-MIMO manner. Specifically, up to eight users / STAs may be allocated to the 106-RU, and the number of users / STAs allocated to the 106-RU is determined based on the 3-bit information (i.e., y2y1y0). For example, when the 3-bit information (y2y1y0) corresponds to a decimal value N, the number of users / STAs allocated to the 106-RU may be N+1.

[0143] Basically, one user / STA may be assigned to each of multiple RUs, and different users / STAs may be assigned to different RUs. For RUs of a certain size or larger (e.g., 106, 242, 484, 996-tone, ...), multiple users / STAs may be assigned to one RU, and the MU-MIMO scheme may be applied to the multiple users / STAs.

[0144] The set of user-specific fields contains information on how all users (STAs) of the PPDU decode their payload. The user-specific fields may contain zero or more user block fields. A non-final user block field contains two user fields (i.e., information used for decoding at two STAs). A final user block field contains one or two user fields. The number of user fields may be indicated by the RU allocation subfield of HE-SIG-B, the number of symbols of HE-SIG-B, or the MU-MIMO users field of HE-SIG-A. The user-specific fields may be encoded separately or independently from the common fields.

[0145] FIG. 12 is a diagram for explaining the MU-MIMO scheme in which multiple users / STAs are assigned to one RU.

[0146] In the example of FIG. 12, it is assumed that the value of the RU allocation subfield is 01000010. This corresponds to the case where y2y1y0=010 in 01000y2y1y0. 010 corresponds to 2 in decimal (i.e., N=2), and it can indicate that 3 (=N+1) users are allocated to one RU. In this case, one 106-RU and five 26-RUs may be arranged in order from the leftmost to the rightmost of a specific 20 MHz band / channel. Three users / STAs may be allocated to the 106-RU in a MU-MIMO manner. As a result, a total of eight users / STAs are allocated to the 20 MHz band / channel, and the user-specific field of the HE-SIG-B may include eight user fields (i.e., four user block fields). The eight user fields may be assigned to RUs as shown in FIG. 12.

[0147] The user fields may be configured based on two formats. The user fields for MU-MIMO allocation may be configured in a first format, and the user fields for non-MU-MIMO allocation may be configured in a second format. With reference to an example in FIG. 12, user fields 1 to 3 may be based on the first format, and user fields 4 to 8 may be based on the second format. The first format and the second format may include bit information of the same length (e.g., 21 bits).

[0148] The user field of the first format (i.e., a format for MU-MIMO allocation) may be configured as follows: For example, among the total 21 bits of one user field, B0 to B10 include identification information of the user (e.g., STA-ID, AID, partial AID, etc.), B11 to B14 include spatial configuration information such as the number of spatial streams for the user, B15 to B18 include modulation and coding scheme (MCS) information applied to the Data field of the PPDU, B19 is defined as a reserved field, and B20 may include coding type (e.g., binary convolutional coding (BCC) or low-density parity check (LDPC)) information applied to the Data field of the PPDU.

[0149] The user field of the second format (i.e., a format for non-MU-MIMO allocation) may be configured as follows: For example, among the total 21 bits of one user field, B0 to B10 may include identification information of the user (e.g., STA-ID, AID, partial AID, etc.), B11 to B13 may include information on the number of spatial streams (NSTS) applied to the RU, B14 may include information indicating whether beamforming is possible (or whether a beamforming steering matrix is ​​applicable), B15 to B18 may include information on modulation and coding scheme (MCS) applied to the Data field of the PPDU, B19 may include information indicating whether dual carrier modulation (DCM) is applicable, and B20 may include information on a coding type (e.g., BCC or LDPC) applied to the Data field of the PPDU.

[0150] The MCS, MCS information, MCS index, MCS field, etc. used in the present disclosure may be represented as a specific index value. For example, the MCS information may be represented as index 0 to index 11. The MCS information may include information about a constellation modulation type (e.g., BPSK, QPSK, 16-QAM, 64-QAM, 256-QAM, 1024-QAM, etc.) and information about a coding rate (e.g., 1 / 2, 2 / 3, 3 / 4, 5 / 6, etc.). The MCS information may omit information about a channel coding type (e.g., BCC or LDPC).

[0151] FIG. 13 shows an example of a PPDU format to which the present disclosure can be applied.

[0152] The PPDU in Fig. 13 may be variously named, such as EHT PPDU, transmit PPDU, receive PPDU, first type or Nth type PPDU, etc. For example, the PPDU or EHT PPDU of the present disclosure may be variously named, such as transmit PPDU, receive PPDU, first type or Nth type PPDU, etc. Also, the EHT PPU can be used in an EHT system and / or a new wireless LAN system that improves the EHT system.

[0153] The EHT MU PPDU in Fig. 13 corresponds to a PPDU that carries one or more data (or PSDUs) for one or more users. That is, the EHT MU PPDU may be used for both SU transmission and MU transmission. For example, the EHT MU PPDU may correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0154] The EHT-SIG is omitted in the EHT TB PPDU in Fig. 13, unlike the EHT MU PPDU. A STA that receives a trigger for UL MU transmission (e.g., a trigger frame or a TRS) can perform UL transmission based on the EHT TB PPDU format.

[0155] In the example of the EHT PPDU format in FIG. 13, L-STF to EHT-LTF correspond to a preamble or a physical preamble, and may be generated / transmitted / received / acquired / decoded in the physical layer.

[0156] The subcarrier frequency spacing of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal SIGNAL), and EHT-SIG fields (these are referred to as pre-EHT modulated fields) may be determined to be 312.5 kHz. The subcarrier frequency spacing of the EHT-STF, EHT-LTF, Data, and PE fields (these are referred to as EHT modulated fields) may be determined to be 78.125 kHz. That is, the tone / subcarrier indexes of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-SIG fields may be displayed in units of 312.5 kHz, and the tone / subcarrier indexes of the EHT-STF, EHT-LTF, Data, and PE fields may be displayed in units of 78.125 kHz.

[0157] The L-LTF and L-STF in FIG. 13 may be configured in the same manner as the corresponding fields of the PPDU described in FIG. 6 and FIG.

[0158] The L-SIG field in FIG. 13 may be composed of 24 bits and may be used to communicate rate and length information. For example, the L-SIG field may include a 4-bit Rate field, a 1-bit Reserved bit, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field. For example, the 12-bit Length field may include information regarding the length or time duration of the PPDU. For example, the value of the 12-bit Length field may be determined based on the type of PPDU. For example, for a non-HT, HT, VHT, or EHT PPDU, the value of the Length field may be determined as a multiple of 3. For example, for a HE PPDU, the value of the Length field may be determined as a multiple of 3+1 or a multiple of 3+2.

[0159] For example, the transmitting STA may apply BCC encoding based on a coding rate of 1 / 2 to the 24-bit information of the L-SIG field. Then, the transmitting STA may obtain 48 BCC coded bits. BPSK modulation may be applied to the 48 coded bits to generate 48 BPSK symbols. The transmitting STA may map the 48 BPSK symbols to positions excluding pilot subcarriers (e.g., {subcarrier index -21, -7, +7, +21}) and DC subcarriers (e.g., {subcarrier index 0}). As a result, the 48 BPSK symbols may be mapped to subcarrier indexes -26 to -22, -20 to -8, -6 to -1, +1 to +6, +8 to +20, and +22 to +26. The transmitting STA may further map the signal of {-1, -1, -1, 1} to subcarrier indexes {-28, -27, +27, +28}. This signal may be used for channel estimation for the frequency range corresponding to {-28, -27, +27, +28}.

[0160] The transmitting STA can generate a RL-SIG, which is generated identically to the L-SIG. BPSK modulation is applied to the RL-SIG. Based on the presence of the RL-SIG, the receiving STA can determine that the received PPDU is a HE PPDU or an EHT PPDU.

[0161] A U-SIG (Universal SIG) may be inserted after the RL-SIG in Fig. 13. The U-SIG may be variously named, such as a first SIG field, a first SIG, a first type SIG, a control signal, a control signal field, a first (type) control signal, etc.

[0162] The U-SIG may include N-bit information and may include information for identifying the type of EHT PPDU. For example, the U-SIG may be configured based on two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG may have a duration of 4us, and the U-SIG may have a total duration of 8us. Each symbol of the U-SIG may be used to transmit 26-bit information. For example, each symbol of the U-SIG may be transmitted and received based on 52 data tones and 4 pilot tones.

[0163] In the U-SIG (or U-SIG field), for example, A-bit information (e.g., 52 un-coded bits) may be transmitted, and the first symbol of the U-SIG (e.g., U-SIG-1) transmits the first X-bit information (e.g., 26 un-coded bits) of the total A-bit information, and the second symbol of the U-SIG (e.g., U-SIG-2) transmits the remaining Y-bit information (e.g., 26 un-coded bits) of the total A-bit information. For example, the transmitting STA can obtain the 26 un-coded bits included in each U-SIG symbol. The transmitting STA can perform convolution encoding (e.g., BCC encoding) based on a rate of R=1 / 2 to generate 52-coded bits and perform interleaving on the 52-coded bits. The transmitting STA can perform BPSK modulation on the interleaved 52-coded bits to generate 52 BPSK symbols assigned to each U-SIG symbol. One U-SIG symbol may be transmitted based on 56 tones (subcarriers) from subcarrier index -28 to subcarrier index +28, excluding DC index 0. The 52 BPSK symbols generated by the transmitting STA may be transmitted based on the remaining tones (subcarriers) excluding the pilot tones -21, -7, +7, and +21.

[0164] For example, the A-bit information (e.g., 52 un-coded bits) transmitted by the U-SIG may include a CRC field (e.g., a 4-bit long field) and a tail field (e.g., a 6-bit long field). The CRC field and the tail field may be transmitted in the second symbol of the U-SIG. The CRC field may be generated based on the 26 bits assigned to the first symbol of the U-SIG and the remaining 16 bits in the second symbol excluding the CRC / tail field, and may be generated based on a conventional CRC calculation algorithm. The tail field may also be used to terminate the trellis of a convolutional decoder, and may be set to 0, for example.

[0165] The A-bit information (e.g., 52 un-coded bits) transmitted by the U-SIG (or U-SIG field) can be distinguished into version-independent bits and version-dependent bits. For example, the size of the version-independent bits may be fixed or variable. For example, the version-independent bits may be assigned only to the first symbol of the U-SIG, or the version-independent bits may be assigned to both the first and second symbols of the U-SIG. For example, the version-independent bits and the version-dependent bits may be referred to by various names, such as the first control bit and the second control bit.

[0166] For example, the version independent bits of the U-SIG may include a 3-bit physical layer version identifier. For example, the 3-bit physical layer version identifier may include information about a physical layer version (PHY version) of the transmitted / received PPDU. For example, a first value of the 3-bit physical layer version identifier may indicate that the transmitted / received PPDU is an EHT PPDU. In other words, when the transmitting STA transmits an EHT PPDU, the transmitting STA may set the 3-bit physical layer version identifier to a first value. In other words, the receiving STA may determine that the received PPDU is an EHT PPDU based on the physical layer version identifier having the first value.

[0167] For example, the version independent bits of the U-SIG may include a one-bit UL / DL flag field, where a first value of the one-bit UL / DL flag field is associated with UL communications and a second value of the UL / DL flag field is associated with DL communications.

[0168] For example, the version independent bits of the U-SIG may include information regarding the length of a transmission opportunity (TXOP) and information regarding a BSS color ID.

[0169] For example, when EHT PPDUs are classified into various types (e.g., EHT PPDUs associated with SU mode, EHT PPDUs associated with MU mode, EHT PPDUs associated with TB mode, EHT PPDUs associated with Extended Range transmission, etc.), information regarding the type of EHT PPDU may be included in the version-dependent bits of the U-SIG.

[0170] For example, the U-SIG may include information regarding 1) a bandwidth field including information regarding the bandwidth, 2) a field including information regarding the MCS technique applied to the EHT-SIG, 3) an indication field including information regarding whether or not a DCM technique is applied to the EHT-SIG, 4) a field including information regarding the number of symbols used for the EHT-SIG, 5) a field including information regarding whether or not the EHT-SIG is generated across the entire band, 6) a field including information regarding the type of EHT-LTF / STF, and 7) a field indicating the length of the EHT-LTF and the CP length.

[0171] Preamble puncturing may be applied to the PPDU in FIG. 13. Preamble puncturing means applying puncturing to a portion of the entire band of the PPDU (e.g., the secondary 20 MHz band). For example, when an 80 MHz PPDU is transmitted, the STA applies puncturing to the secondary 20 MHz band of the 80 MHz band, and can transmit the PPDU only in the primary 20 MHz band and the secondary 40 MHz band.

[0172] For example, the preamble puncturing pattern may be set in advance. For example, when the first puncturing pattern is applied, puncturing may be applied only to the secondary 20 MHz band in the 80 MHz band. For example, when the second puncturing pattern is applied, puncturing may be applied only to any one of the two secondary 20 MHz bands included in the secondary 40 MHz band in the 80 MHz band. For example, when the third puncturing pattern is applied, puncturing may be applied only to the secondary 20 MHz band included in the primary 80 MHz band in the 160 MHz band (or 80+80 MHz band). For example, when the fourth puncturing pattern is applied, the primary 40 MHz band included in the primary 80 MHz band in the 160 MHz band (or 80+80 MHz band) is present, and puncturing may be applied to at least one 20 MHz channel that does not belong to the primary 40 MHz band.

[0173] The information regarding the preamble puncturing applied to the PPDU may be included in the U-SIG and / or the EHT-SIG, for example, a first field of the U-SIG may include information regarding the contiguous bandwidth of the PPDU, and a second field of the U-SIG may include information regarding the preamble puncturing applied to the PPDU.

[0174] For example, the U-SIG and the EHT-SIG may include information about preamble puncturing based on the following method. When the bandwidth of the PPDU exceeds 80 MHz, the U-SIG may be configured in units of 80 MHz individually. For example, when the bandwidth of the PPDU is 160 MHz, the PPDU may include a first U-SIG for a first 80 MHz band and a second U-SIG for a second 80 MHz band. In this case, the first field of the first U-SIG may include information about the 160 MHz bandwidth, and the second field of the first U-SIG may include information about the preamble puncturing applied to the first 80 MHz band (i.e., information about the preamble puncturing pattern). Also, the first field of the second U-SIG may include information about the 160 MHz bandwidth, and the second field of the second U-SIG may include information about the preamble puncturing applied to the second 80 MHz band (i.e., information about the preamble puncturing pattern). The EHT-SIG subsequent to the first U-SIG may include information regarding the preamble puncturing applied to the second 80 MHz band (i.e., information regarding the preamble puncturing pattern), and the EHT-SIG subsequent to the second U-SIG may include information regarding the preamble puncturing applied to the first 80 MHz band (i.e., information regarding the preamble puncturing pattern).

[0175] Additionally or alternatively, the U-SIG and the EHT-SIG may include information regarding preamble puncturing based on the following method: The U-SIG may include information regarding preamble puncturing for the entire band (i.e., information regarding the preamble puncturing pattern). That is, the EHT-SIG may not include information regarding preamble puncturing, and only the U-SIG may include information regarding preamble puncturing (i.e., information regarding the preamble puncturing pattern).

[0176] The U-SIG may be configured in units of 20 MHz. For example, when an 80 MHz PPDU is configured, the U-SIG may be duplicated. That is, four identical U-SIGs may be included in the 80 MHz PPDU. PPDUs exceeding the 80 MHz bandwidth may contain different U-SIGs.

[0177] The EHT-SIG in FIG. 13 may include control information for the receiving STA. The EHT-SIG may be transmitted in at least one symbol, and one symbol may have a length of 4us. Information regarding the number of symbols used for the EHT-SIG may be included in the U-SIG.

[0178] The EHT-SIG may include the technical features of the HE-SIG-B described in Figures 11 and 12. For example, the EHT-SIG may include a common field and a user-specific field, the same as the example of Figure 8. The common field of the EHT-SIG may be omitted, and the number of user-specific fields may be determined based on the number of users.

[0179] 11, the common fields of the EHT-SIG and the user-specific fields of the EHT-SIG may be coded separately. A user block field included in the user-specific fields includes information for two user fields, but the last user block field included in the user-specific fields may include one or two user fields. That is, a user block field of the EHT-SIG may include up to two user fields. Similarly to the example of FIG. 12, each user field may be associated with a MU-MIMO allocation or a non-MU-MIMO allocation.

[0180] Consistent with the example of FIG. 11, the common field of the EHT-SIG may include CRC bits and Tail bits, where the length of the CRC bits may be determined to be 4 bits, and the length of the Tail bits may be determined to be 6 bits and set to 000000.

[0181] As in the example of FIG. 11, the common field of the EHT-SIG may include RU allocation information. The RU allocation information may refer to information about the location of RUs to which multiple users (i.e., multiple receiving STAs) are assigned. The RU allocation information may be configured in 8-bit (or N-bit) units.

[0182] A mode in which the common field of the EHT-SIG is omitted may be supported. The mode in which the common field of the EHT-SIG is omitted may be called a compressed mode. When the compressed mode is used, multiple users of the EHT PPDU (i.e., multiple receiving STAs) can decode the PPDU (e.g., the data field of the PPDU) based on non-OFDMA. That is, multiple users of the EHT PPDU can decode the PPDU (e.g., the data field of the PPDU) received in the same frequency band. When the non-compressed mode is used, multiple users of the EHT PPDU can decode the PPDU (e.g., the data field of the PPDU) based on OFDMA. That is, multiple users of the EHT PPDU can receive the PPDU (e.g., the data field of the PPDU) in different frequency bands from each other.

[0183] The EHT-SIG may be configured based on various MCS schemes. As described above, information regarding the MCS scheme applied to the EHT-SIG may be included in the U-SIG. The EHT-SIG may be configured based on the DCM scheme. For example, among N data tones (e.g., 52 data tones) allocated for the EHT-SIG, a first modulation scheme may be applied to consecutive half tones, and a second modulation scheme may be applied to the remaining consecutive half tones. That is, the transmitting STA may modulate specific control information onto a first symbol based on a first modulation scheme and allocate it to the consecutive half tones, and modulate the same control information onto a second symbol based on a second modulation scheme and allocate it to the remaining consecutive half tones. As described above, information regarding whether the DCM scheme is applied to the EHT-SIG (e.g., a 1-bit field) may be included in the U-SIG. The EHT-STF in FIG. 13 may be used to improve automatic gain control (AGC) estimation in a MIMO environment or an OFDMA environment. The EHT-LTF of FIG. 13 may be used to estimate a channel in a MIMO or OFDMA environment.

[0184] Information regarding the type of STF and / or LTF (including information regarding the guard interval (GI) applied to the LTF) may be included in the U-SIG field and / or EHT-SIG field of FIG. 13, etc.

[0185] The PPDU in FIG. 13 (ie, the EHT PPDU) may be configured based on the example of the RU arrangement in FIGS.

[0186] For example, an EHT PPDU transmitted on a 20 MHz band, i.e., a 20 MHz EHT PPDU, may be configured based on the RU in Fig. 8. That is, the RU locations of the EHT-STF, EHT-LTF, and data fields included in the EHT PPDU may be determined as shown in Fig. 8. An EHT PPDU transmitted on a 40 MHz band, i.e., a 40 MHz EHT PPDU, may be configured based on the RU in Fig. 9. That is, the RU locations of the EHT-STF, EHT-LTF, and data fields included in the EHT PPDU may be determined as shown in Fig. 9.

[0187] An EHT PPDU transmitted on the 80 MHz band, i.e., an 80 MHz EHT PPDU, may be configured based on the RU in Figure 10. That is, the RU locations of the EHT-STF, EHT-LTF, and data fields included in the EHT PPDU may be determined as in Figure 10. The tone-plan for 80 MHz in Figure 10 may correspond to two repetitions of the tone-plan for 40 MHz in Figure 9.

[0188] The tone plan for 160 / 240 / 320 MHz may be configured to repeat the pattern of FIG. 9 or FIG. 10 multiple times.

[0189] The PPDU in FIG. 13 may be identified as an EHT PPDU based on the following method.

[0190] The receiving STA may determine the type of the received PPDU as EHT PPDU based on the following: 1) the first symbol after the L-LTF signal of the received PPDU is BPSK, 2) an RL-SIG in which the L-SIG of the received PPDU is repeated is detected, and 3) the result of applying modulo 3 arithmetic to the value of the Length field of the L-SIG of the received PPDU (i.e., the remainder when divided by 3) is detected as 0, the received PPDU may be determined as EHT PPDU. If the received PPDU is determined as EHT PPDU, the receiving STA may determine the type of EHT PPDU based on bit information included in the symbol after the RL-SIG in FIG. 13. In other words, the receiving STA may determine the received PPDU as EHT PPDU based on 1) the first symbol after the L-LTF signal which is BSPK, 2) an RL-SIG which is consecutive to the L-SIG field and is the same as the L-SIG, and 3) an L-SIG including a Length field in which the result of applying modulo 3 is set to 0.

[0191] For example, the receiving STA may determine that the type of the received PPDU is an HE PPDU based on the following: 1) the first symbol after the L-LTF signal is BPSK, 2) an RL-SIG in which the L-SIG is repeated is detected, and 3) the result of applying modulo 3 to the Length value of the L-SIG is detected as 1 or 2, the received PPDU may be determined to be an HE PPDU.

[0192] For example, the receiving STA can determine the type of the received PPDU as non-HT, HT, or VHT PPDU based on the following: For example, if 1) the first symbol after the L-LTF signal is BPSK, and 2) an RL-SIG in which the L-SIG is repeated is not detected, the received PPDU may be determined as a non-HT, HT, or VHT PPDU. Also, even if the receiving STA detects a repetition of the RL-SIG, if the result of applying modulo 3 to the Length value of the L-SIG is detected as 0, the received PPDU may be determined as a non-HT, HT, or VHT PPDU.

[0193] The PPDU in Figure 13 may be used to transmit and receive various types of frames. For example, the PPDU in Figure 13 may be used to transmit and receive one or more (simultaneous) control frames, management frames, or data frames.

[0194] Below, we will explain TWT (target wake time).

[0195] TWT is a power saving (PS) technology that can improve the energy efficiency of non-AP STAs by defining a service period (SP) between an AP and non-AP STAs, sharing information about the SP, and reducing medium contention. An STA that makes a request / suggest / demand in the TWT setup phase can be called a TWT requesting STA. An AP that responds to the request by accepting / rejecting can be called a TWT responding STA. The setup phase may include a process of determining / defining a TWT request from an STA to an AP, the type of TWT operation to be performed, and the frame type to be transmitted and received. TWT operations can be divided into individual TWT and broadcast TWT.

[0196] FIG. 14 is a diagram for explaining an example of an individual TWT operation to which the present disclosure can be applied.

[0197] Individual TWT is a mechanism for data exchange after AP and non-AP STA negotiate the awake / doze status of non-AP STA by transmitting and receiving TWT request / response frames. In the example of FIG. 14, AP and STA1 can form a trigger-enabled TWT agreement by a TWT request frame and a TWT response frame. Here, the method used by STA1 is a solicited TWT method, in which STA1 transmits a TWT request frame to the AP and receives information for TWT operation from the AP using a TWT response frame. Meanwhile, STA2 using an unsolicited TWT method can receive information on the setting of a trigger-enabled TWT agreement from the AP using an unsolicited TWT response. Specifically, STA2 can calculate the next TWT by adding a specific number to the current TWT value. In a trigger-enabled TWT SP, the AP can transmit a trigger frame to the STA. The trigger frame can inform the STA that there is buffered data in the AP. In response, STA1 can inform the AP of its awake state by transmitting a PS-Poll frame. Also, STA2 can inform the AP of its awake state by transmitting a QoS Null frame. Here, the data frames transmitted by STA1 and STA2 can be frames in TB PPDU format. After checking the states of STA1 and STA2, the AP can transmit DL MU PPDU to the awake STAs. When the TWT SP expires, STA1 and STA2 can switch to a doze state.

[0198] FIG. 15 is a diagram for explaining an example of a broadcast TWT operation to which the present disclosure can be applied.

[0199] The broadcast TWT is a TWT in which a non-AP STA (or a TWT scheduling STA) obtains information on a target beacon transmission time (TBTT) and a listen interval by transmitting and receiving a TWT request / response frame with an AP (or a TWT scheduled STA). Here, a negotiation operation for the TBTT may be performed. Based on this, the AP may define a frame including TWT scheduling information using a beacon frame. In FIG. 15, STA1 performs a solicited TWT operation, and STA2 performs an unsolicited TWT operation. The AP may transmit a DL MU PPDU after confirming the awake state of the STA using a trigger transmitted by itself. This may be the same as the process of an individual TWT. In the broadcast TWT, a trigger-enabled TWT SP including a beacon frame may be repeated multiple times at a certain period.

[0200] The TWT information may be conveyed by a TWT information frame and a TWT information element.

[0201] FIG. 16 is a diagram illustrating an example of a TWT information element format.

[0202] The TWT information frame is sent by a STA to request or deliver information about a TWT agreement and is sent by one of the STAs of an existing TWT agreement. The action frame of the TWT information frame includes a TWT information field. The TWT information field may include a 3-bit TWT flow identifier subfield, a 1-bit response requested subfield, a 1-bit next TWT request subfield, a 2-bit next TWT subfield size subfield, a 1-bit all TWT subfield, and a 0 / 32 / 48 / 64-bit next TWT subfield.

[0203] The size of the TWT information field may vary depending on the size of the next TWT field. The TWT flow identifier subfield includes an identifier of the TWT flow for which TWT information is requested or provided. The TWT flow identifier subfield may be reserved if the value of the all TWT subfield is 1.

[0204] The response requested subfield can indicate whether the STA transmitting the frame including the TWT information field requests that a TWT information frame be transmitted in response to the frame. When the response requested subfield is set to 0, the STA can be requested not to transmit a TWT information frame in response to the frame. When the response requested subfield is set to 1, the STA can be requested to transmit a TWT information frame in response to the frame.

[0205] The next TWT request subfield may be set to 1 to indicate that the TWT information frame is a request for transmission of a TWT information frame containing a next TWT field with a length other than 0. Otherwise, the next TWT request subfield may be set to 0.

[0206] The values ​​of the next TWT subfield size subfield are 0, 1, 2, and 3, which indicate that the size of the next TWT subfield is 0, 32, 48, and 64, respectively.

[0207] The all TWT subfield may be set to 1 to indicate that the TWT information frame reschedules all TWTs. Otherwise, the all TWT subfield may be set to 0.

[0208] The next TWT subfield may have a variable length depending on the value of the next TWT subfield size. The value included in the next TWT subfield may have a value corresponding to the least significant portion of a timing synchronization function (TSF) in the next TWT for the TWT identified by the TWT flow identifier subfield.

[0209] FIG. 17 is a diagram illustrating an example of a TWT information element format.

[0210] The TWT information element may be transmitted and received in a beacon, a probe response, a (re)association response frame, etc. The TWT information element may include an element ID field, a length field, a control field, and a TWT parameter information field.

[0211] The control field of the TWT information element has the same format regardless of whether it is an individual TWT or a broadcast TWT.

[0212] The NDP paging indication subfield may have a value of 1 if the NDP paging field is present and may have a value of 0 if the NDP paging field is not present.

[0213] The responder PM mode subfield may indicate a Power Management (PM) mode.

[0214] The negotiation type subfield may indicate whether the information contained in the TWT element is for negotiation of parameters of a broadcast TWT or individual TWT(s), or for a wake TBTT interval.

[0215] For example, if the negotiation type subfield has a value of 0, the TWT subfield is for a future individual TWT SP start time, and the TWT element contains one individual TWT parameter set, which may correspond to an individual TWT negotiation between the TWT requester STA and the TWT responder STA, or an individual TWT announcement by the TWT responder.

[0216] For example, when the negotiation type subfield has a value of 1, the TWT subfield is for the next TBTT time, and the TWT element includes one individual TWT parameter set, which may correspond to wake TBTT and wake interval negotiation between a TWT scheduled STA and a TWT scheduling AP.

[0217] For example, if the negotiation type subfield has a value of 2, the TWT subfield is for a future broadcast TWT SP start time, and the TWT element includes one or more broadcast TWT parameter sets, which may correspond to providing a broadcast TWT schedule to TWT-scheduled STAs by including the TWT element in a broadcast management frame transmitted by the TWT scheduling AP.

[0218] For example, if the negotiation type subfield has a value of 3, the TWT subfield is for a future broadcast TWT SP start time, and the TWT element includes one or more broadcast TWT parameter sets. This may correspond to managing membership in the broadcast TWT schedule by including the TWT element in an individually addressed management frame transmitted by either the TWT scheduled STA or the TWT scheduling AP.

[0219] The TWT information frame disabled subfield may be set to 1 to indicate that reception of TWT information frames by the STA is disabled; otherwise, it may be set to 0.

[0220] The wake duration unit subfield indicates the units of the nominal minimum TWT wake duration field. The wake duration unit subfield may be set to 0 if the unit is 256us and set to 1 if the unit is TU. If not a HE / EHT STA, the wake duration unit subfield may be set to 0.

[0221] The most significant bit (MSB) of the negotiation type field may correspond to a broadcast field. If the broadcast field is 1, one or more broadcast TWT parameter sets may be included in the TWT element. If the broadcast field is 0, only one individual TWT parameter set may be included in the TWT element. A TWT element with the broadcast field set to 1 may be referred to as a broadcast TWT element.

[0222] Fig. 18 is a diagram illustrating an example of an individual TWT parameter set field format, and Fig. 19 is a diagram illustrating an example of a broadcast TWT parameter set field format.

[0223] The TWT parameter information field included in the TWT element in FIG. 17 may have different configurations depending on whether the TWT is an individual TWT or a broadcast TWT.

[0224] If it is an individual TWT, the TWT parameter information field in the TWT element contains a single individual TWT parameter set field.

[0225] For a broadcast TWT, the TWT parameter information field in the TWT element includes one or more broadcast TWT parameter set fields, each of which may include specific information about one broadcast TWT.

[0226] As shown in Figures 18 and 19, the individual TWT parameter set field and the broadcast TWT parameter set field include common subfields.

[0227] The request type subfield may have the same size in the individual TWT parameter set field and the broadcast TWT parameter set field, but may have different detailed configurations, as described below.

[0228] The target wake time subfield indicates the start time of a later scheduled individual / broadcast TWT SP.

[0229] The nominal maximum TWT wake duration subfield indicates the minimum unit that the TWT requesting STA expects to have to wake up to complete a frame exchange associated with the TWT flow identifier in the TWT wake interval duration, where the TWT wake interval may refer to the average time between consecutive TWT SPs that the TWT requesting STA expects.

[0230] The TWT Wake Interval Mantissa subfield is the binary value of the TWT wake interval value, expressed in microseconds.

[0231] Referring to FIG. 18, the TWT group assignment subfield, the TWT channel, and the NDP paging subfields are only included in the individual TWT parameter set field.

[0232] The TWT group assignment subfield provides the TWT requesting STA with information about the TWT group to which the STA is assigned. The TWT value in the TWT group can be calculated using this information. The TWT value of the STA may be equal to the value of the zero offset and the value of the TWT offset multiplied by the value of the TWT unit.

[0233] The TWT Channel subfield indicates a bitmap indicating allowed channels. When sent by a TWT requesting STA, the TWT Channel subfield may include a bitmap indicating channels that the STA requests to use as temporary fundamental channels in the TWT SP. When sent by a TWT responding STA, the TWT Channel subfield may include a bitmap indicating channels on which the TWT request is allowed.

[0234] The NDP paging subfield is optional and may include an identifier of the STA being paged, information regarding the maximum number of TWT wake intervals between NDP paging frames, etc.

[0235] Referring to FIG. 19, the broadcast TWT info subfield is included only 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 a specific broadcast TWT for which a STA requests to join or provides TWT parameters, depending 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 schedule of the broadcast TWT.

[0236] Next, the detailed structure of the request type subfield will be described.

[0237] First, the format of the request type subfield of the individual TWT parameter set field will be described with reference to FIG.

[0238] The TWT request subfield can indicate whether it is a requesting STA or a responding STA. If its value is 1, it indicates that it is a TWT requesting STA or a scheduled STA, and if its value is 0, it indicates that it is a TWT responding STA or a scheduling AP.

[0239] The TWT setup command subfield can indicate commands such as Request, Suggest, Demand, Accept, Alternate, Dictate, and Reject.

[0240] The trigger subfield indicates whether or not a trigger frame is used in the TWT SP. If the value is 1, the trigger is used, and if the value is 0, the trigger is not used.

[0241] The implicit subfield can indicate implicit or explicit TWT, with a value of 1 indicating implicit TWT and a value of 0 indicating explicit TWT.

[0242] The flow type subfield can indicate the type of interaction between a TWT requesting STA (or a TWT scheduled STA) and a TWT responding STA (or a TWT scheduling AP). If the value is 1, it can indicate announced TWT in which the STA transmits a PS-Poll or APSD (automatic power save delivery) trigger frame and sends a wake-up signal to the AP before a frame other than the trigger frame is transmitted from the AP to the STA. If the value is 0, it can indicate unknown TWT.

[0243] The TWT flow identifier subfield may contain a 3-bit value that uniquely identifies the specific information for this TWT request from other requests made between the same TWT requesting STA and TWT responding STA pair.

[0244] The TWT wake interval exponent subfield can set the TWT wake interval value in binary microseconds. In the case of an individual TWT, it can mean the interval between individual TWT SPs. The TWT wake interval of the requesting STA may be defined as [TWT Wake Interval Mantissa * 2 * TWT Wake Interval Exponent].

[0245] The TWT protection subfield can indicate whether to use a TWT protection mechanism. If its value is 1, the TXOP in the TWT SP may be initiated with a NAV protection mechanism such as a (MU)RTS / CTS or CTS-to-self frame, and if its value is 0, the NAV protection mechanism may not be applied.

[0246] 19, some of the 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, so the description thereof will be omitted. The subfields included only in the broadcast TWT parameter set will be described below.

[0247] 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.

[0248] The broadcast TWT recommendation subfield may indicate a recommendation for the frame type to be transmitted by the AP in the broadcast TWT SP with a value from 1 to 7.

[0249] The last bit of the request type subfield of the broadcast TWT parameter set field may be reserved.

[0250] Method for configuring restricted TWT-related TWT information

[0251] In recent years, as wired / wireless traffic has rapidly increased, latency-sensitive traffic has also increased significantly. Latency-sensitive traffic includes real-time audio / video transmission, and with the proliferation of multimedia devices, the need to support this traffic in wireless environments is increasing. However, compared to wired environments, there are many considerations to be made in supporting latency-sensitive traffic in wireless environments. In wireless environments, the transmission speed is lower than that of wired environments, and the problem of interference from the surroundings must also be considered. In particular, in wireless LAN systems, a large number of STAs must compete equally for medium occupation in the ISM (Industry-Science-Medical) band, making it relatively difficult to support latency-sensitive traffic compared to cellular communication networks based on wireless resource scheduling by a central base station. In this disclosure, a new scheme for supporting latency-sensitive traffic in a wireless LAN system is described.

[0252] In the present disclosure, latency may refer to the latency defined in the IEEE 802.11 series of standards. For example, it may refer to the time from when a frame to be transmitted enters a queue of the MAC layer of a transmitting STA, when the transmission of the transmitting STA is successfully completed at the PHY layer, when the transmitting STA receives an ACK / block ACK, etc. from a receiving STA, until the frame is deleted from the MAC layer queue of the transmitting STA. In addition, in the present disclosure, a non-AP STA that supports transmission of latency sensitive data may be called a low latency STA. And data other than latency sensitive data may be called regular data.

[0253] FIG. 20 is a diagram for explaining an example of limited TWT operation.

[0254] The restricted TWT (r-TWT) can help ensure data transmission possibility for low latency STAs preferentially over other STAs by setting a special broadcast TWT for the low latency STAs transmitting latency sensitive data. The STAs can establish membership to one or more r-TWT schedules with the AP. Here, the r-TWT agreement may be established by the same process as the broadcast TWT agreement, and the broadcast TWT element therefor may be defined to include an r-TWT parameter set field. For example, the r-TWT parameter set field may refer to a specific broadcast TWT parameter set field that is distinguished from other broadcast TWT parameter set fields. That is, the r-TWT parameter set field may be a special case of the broadcast TWT parameter set field. In addition, the AP can announce the r-TWT SP.

[0255] Basically, when another STA supporting r-TWT operation is a TXOP holder, the TXOP must end before the start time of the r-TWT SP advertised by the associated AP, so that the STA associated with the r-TWT (i.e., a low latency STA) can transmit and receive traffic preferentially in the r-TWT SP compared to the other STAs.

[0256] In this disclosure, as previously mentioned, a low latency STA associated with a particular r-TWT is referred to as a member r-TWT scheduled STA, and other STAs are referred to as non-member STAs. A non-member STA may be an STA that has the capability to support r-TWT operations but is not a member of any r-TWT, or that supports r-TWT operations but is a member of another r-TWT, or that does not have the capability to support r-TWT operations.

[0257] STAs (e.g., low latency STAs) that support broadcast TWT limited SP (or r-TWT SP) operation can inform the AP that they must transmit latency sensitive data based on r-TWT operation. If the AP supports r-TWT operation / mode, the AP can transmit frames to the low latency STAs and other STAs that include scheduling information for the TWT requested by each STA. For example, to perform operations for r-TWT, non-AP STAs can obtain r-TWT-related information from the AP using beacon frames, probe response frames, (re)association response frames, or frames of other yet to be defined formats (e.g., broadcast, advertisement, and public use frames).

[0258] According to the restricted TWT operation, a separate TXOP (i.e., access of other STAs is restricted) can be reserved in the r-TWT SP using a NAV such as (MU)RTS / CTS or CTS-to-self, or a quiet interval. Before a specific r-TWT SP starts, if there is a TXOP of another STA (i.e., a non-member STA) other than the STA having membership to the specific r-TWT schedule, it must be stopped. Then, the TXOP of the other STA (i.e., a non-member STA) may be performed after the specific r-TWT SP ends. This can be called a TXOP rule-based operation for the r-TWT SP of a non-member STA.

[0259] In the example of FIG. 20, STA1 may correspond to a low latency STA, and STA2 may correspond to a STA that transmits and receives regular data. The AP may inform the STA of r-TWT-related information using a frame such as a beacon. In this case, according to the TXOP rule for the r-TWT SP, STA2, which is a TXOP holder, must end the TXOP before the start time of any r-TWT SP advertised by the associated AP.

[0260] In the following, a method for configuring / defining new TWT information in relation to restricted TWT will be described.

[0261] As described above, the TWT information frame may be used for operations such as suspending or resuming a TWT SP allocated for a certain period in an individual TWT or a broadcast TWT. In this regard, when the value of the all TWT subfield (i.e., all TWT field) in the TWT information field as shown in FIG 16 is 1, a STA (e.g., AP STA / non-AP STA) may know the time point of resumption from the value of the next TWT subfield (i.e., next TWT field).

[0262] However, there is no space within the existing TWT information field to separately indicate information related to the r-TWT SP.

[0263] For example, in the case of the existing TWT information field, when the value of the all TWT subfield is 1, the value of the TWT flow Identifier subfield is reserved, so the value of the subfield may indicate whether the TWT SP corresponds to an r-TWT SP that is not an individual TWT / broadcast TWT SP.

[0264] In the above-mentioned method, it is not possible to fully include information related to the restricted TWT, and the existing TWT information frame only includes information related to the broadcast TWT, which may correspond to information not related to the restricted TWT.

[0265] In this regard, a method of signaling a new TWT information frame / TWT information field including information related to the r-TWT SP may be required. This signaling may clarify the information transmission between the STA and the AP that supports the restricted TWT.

[0266] Therefore, this disclosure proposes a method to configure / define new TWT information for r-TWT SP.

[0267] Specifically, we propose a method of signaling an r-TWT information field to indicate that the TWT is an r-TWT SP, and a method of indicating whether data transmission and reception is between an AP and a STA (e.g., UL / DL transmission and reception) or between STAs (e.g., Peer to Peer, P2P transmission and reception) within the r-TWT SP.

[0268] The names or configuration order of the fields / subfields described below are examples for the sake of clarity, and the proposals of the present disclosure are not limited thereto. That is, the names or configuration order of the fields / subfields described below may be changed and applied.

[0269] Furthermore, the STAs described below may include AP STAs or non-AP STAs.

[0270] The embodiments described below are divided for clarity of explanation, and each of the embodiments may be applied independently, or part / all of the configuration of one embodiment may be combined / joined / substituted for part / all of the configuration of another embodiment.

[0271] Example 1

[0272] In this embodiment, a method for defining / designing a TWT information frame / field for indicating / transmitting the above-mentioned r-TWT SP related information is proposed.

[0273] FIG. 21 illustrates an example of an r-TWT related information frame according to the present disclosure.

[0274] Referring to FIG. 21, the r-TWT related information frame may correspond to a newly designed / defined r-TWT information frame for indicating information related to an r-TWT SP.

[0275] The r-TWT information frame may be transmitted by a STA to request or convey information related to an r-TWT SP. An action frame of the r-TWT information frame may include an r-TWT information field.

[0276] For example, the r-TWT information frame (or r-TWT information field) may include a 1-bit restricted TWT subfield, a 5-bit broadcast TWT ID subfield, a 1-bit P2P subfield, a 1-bit all TWT subfield, a 2-bit next TWT subfield size subfield, and a 0 / 32 / 48 / 64-bit next TWT subfield.

[0277] The restricted TWT subfield may indicate whether the scheduled TWT SP is a broadcast TWT or a restricted TWT, i.e., the restricted TWT subfield may be used to distinguish whether the scheduled TWT SP corresponds to an r-TWT SP.

[0278] If the value of the restricted TWT subfield is 1, it indicates that it is an r-TWT SP, and if the value of the restricted TWT subfield is 0, it indicates that it is a broadcast TWT SP. In this regard, the value of the restricted TWT subfield may be set inversely to the above case.

[0279] The broadcast TWT ID subfield may be used to represent the TWT membership of a STA supporting restricted TWT. Based on the subfield, information regarding the r-TWT SP announced by the AP as the r-TWT SP assigned to the STA belonging to which broadcast TWT ID is confirmed.

[0280] The P2P subfield may indicate whether or not a P2P operation is performed within the scheduled TWT SP.

[0281] If the value of the P2P subfield is 1, it can indicate that P2P operation between STAs supporting restricted TWT (i.e., r-TWT scheduled STAs) is performed between the r-TWT SP. If the value of the P2P subfield is 0, it can indicate that UL / DL data transmission and reception between the AP and the STA is performed instead of P2P operation between the r-TWT SP. In this regard, the value of the P2P subfield can be set opposite to the above case.

[0282] The all TWT subfield may indicate whether to reschedule all TWT SPs assigned to the STA.

[0283] When the all TWT subfield is set to 1, the value of the next TWT subfield may signal / indicate information about the rescheduled TWT SPs. If all TWT SPs are not rescheduled, the all TWT subfield may be set to 0.

[0284] In this regard, the suspension information of r-TWT / non r-TWT can be indicated by a combination of the above-mentioned restricted TWT subfield and all TWT subfield.

[0285] For example, when the all TWT subfield is set to 0 and the restricted TWT subfield is set to 1, it indicates that a specific r-TWT scheduling is suspended. When the all TWT subfield is set to 1 and the restricted TWT subfield is set to 1, it indicates that all r-TWT scheduling is suspended. When the all TWT subfield is set to 1 and the restricted TWT subfield is set to 0, it indicates that all non r-TWT scheduling is suspended.

[0286] The next TWT subfield size subfield can indicate the size of the next TWT subfield. Values ​​of 0, 1, 2, and 3 in the next TWT subfield size subfield can indicate that the size of the next TWT subfield is 0, 32, 48, and 64, respectively.

[0287] The next TWT subfield may indicate a specific time for the next TWT of the r-TWT SP. The next TWT subfield may have a variable length depending on the value of the next TWT subfield size.

[0288] For example, a pause for the r-TWT SP can be indicated when the all TWT subfield is set to 1 and the next TWT subfield is set to 0. A pause for the r-TWT SP can be indicated when the all TWT subfield is set to 1 and the next TWT subfield is set to a value greater than 0 (e.g., T resume ), it can be instructed that the r-TWT will resume from the first assigned r-TWT SP after the next TWT (i.e., after the indicated time).

[0289] In the examples according to the present disclosure, T resume may correspond to the resume timing reference and may have a value based on the TSF.

[0290] Hereinafter, with reference to FIG. 22 and FIG. 23, an operation between an r-TWT scheduling AP and an r-TWT scheduled STA based on the above-mentioned r-TWT related information frame will be described.

[0291] FIG. 22 illustrates an example of constrained TWT operation based on an r-TWT information frame according to the present disclosure.

[0292] 22 illustrates an example of an r-TWT information frame for suspending and resuming an r-TWT SP (RSP). In FIG. 22, the AP may correspond to an r-TWT scheduling AP, and the RSP STA 1 may correspond to an r-TWT scheduled STA.

[0293] Further, in Fig. 22, TWT information may be transmitted and received in the form of a TWT information frame, which may correspond to or include the r-TWT information frame / field described above.

[0294] First, the AP can notify r-TWT-related information to STAs including the RSP STA 1 to which the r-TWT SP is assigned, using a management frame such as a beacon frame. Here, the r-TWT-related information may include RSP assignment information, etc.

[0295] RSP STA 1 may send TWT information to the AP to indicate that it will not utilize (ie, suspend) the assigned r-TWT SP.

[0296] As a specific example, in relation to the r-TWT information frame that RSP STA 1 transmits to the AP, the value of the restricted TWT subfield may be set to 1, the value of the broadcast TWT ID subfield may be set to 2, the value of the all TWT subfield may be set to 1, and the value of the next TWT subfield may be set to 0 (i.e., suspension).

[0297] In response to the TWT information, the RSP STA 1 may receive an ACK from the AP. After receiving the ACK, the RSP STA 1 does not transmit or receive data on the r-TWT SP (e.g., RSP #1, RSP #2) until the r-TWT SP is resumed. In other words, the RSP may be postponed or temporarily suspended.

[0298] To indicate that the RSP STA 1 will resume the r-TWT SP, the RSP STA 1 sets the value of the next TWT subfield to the desired resume time (e.g., T resume ) to send TWT information to the AP.

[0299] As a specific example, in relation to the r-TWT information frame that RSP STA 1 sends to the AP, the value of the restricted TWT subfield is set to 1, the value of the broadcast TWT ID subfield is set to 2, the value of the all TWT subfield is set to 1, and the value of the next TWT subfield is set to T resume (e.g., the start time of RSP #3).

[0300] In response to the TWT information, the RSP STA 1 may receive an ACK from the AP. The RSP STA 1 that receives the ACK may then transmit the ACK at time T resume Data transmission and reception can be performed from RSP #3, which is the next assigned r-TWT SP (i.e., the next r-TWT SP). In other words, UL / DL data transmission and reception in the r-TWT SP between the AP and RSP STA 1 is performed for a period of time T resume From then on, the assigned r-TWT SP may be resumed.

[0301] FIG. 23 illustrates another example of constrained TWT operation based on an r-TWT information frame according to the present disclosure.

[0302] 23, an example of an r-TWT information frame for suspending and resuming an r-TWT SP (RSP) / sharing P2P operation information between r-TWT SPs (RSPs) is shown. In FIG. 23, the AP may correspond to an r-TWT scheduling AP, and RSP STA 1 and RSP STA 2 may correspond to r-TWT scheduled STAs.

[0303] Further, in Figure 23, the TWT information may be transmitted or received in the form of a TWT information frame, which may correspond to or include the r-TWT information frame / field described above.

[0304] First, the AP may announce r-TWT-related information to STAs, including RSP STA 1, that are assigned an r-TWT SP, using a management frame such as a beacon frame. Here, the r-TWT-related information may include RSP assignment information, etc. Additionally or alternatively, the r-TWT SP may be configured for P2P transmission / reception, or P2P transmission / reception may be performed within a TXOP specified by separate signaling for P2P transmission / reception within the r-TWT SP (e.g., P2P assisted mode of a triggered TXOP sharing procedure).

[0305] In order to obtain the same membership as the RSP included in a management frame such as a beacon frame, the RSP STA 2 can specify the same broadcast TWT ID value, set the negotiation type value to 3, and send a TWT request to the AP.

[0306] In response to the TWT request, the AP can set the TWT setup command to accept TWT and send a TWT response to the RSP STA 2.

[0307] Thereafter, if RSP STA 1 indicates that it will not utilize (ie, suspend) the assigned r-TWT SP, it may send TWT information to the AP.

[0308] As a specific example, in relation to an r-TWT information frame that RSP STA 1 transmits to an AP, the value of the restricted TWT subfield may be set to 1, the value of the broadcast TWT ID subfield may be set to 3, the value of the P2P subfield may be set to 1, the value of the all TWT subfield may be set to 1, and the value of the next TWT subfield may be set to 0 (i.e., suspension).

[0309] In response to the TWT information, the RSP STA 1 may receive an ACK from the AP. After receiving the ACK, the RSP STA 1 does not transmit or receive data on the r-TWT SP until it resumes the r-TWT SP. That is, the RSP associated with the P2P operation may be suspended or temporarily suspended.

[0310] The AP that has received the above TWT information can inform the RSP STAs having the same broadcast TWT ID that the RSP is to be deferred or suspended. For example, the AP can inform the RSP STAs (including RSP STA 2) that have been assigned an r-TWT SP together with the RSP STA 1, i.e., that the P2P operation in the r-TWT SP performed by the RSP STA 1 is to be deferred or suspended until it is resumed, using a management frame such as a beacon frame.

[0311] Upon receiving such information, the RSP STA 2 will not transmit or receive data (especially P2P transmission or reception) through the r-TWT SP (e.g., RSP #1, RSP #2) until the r-TWT SP is resumed. In other words, the RSP associated with the P2P operation may be postponed or temporarily suspended.

[0312] Additionally or alternatively, since P2P operations are triggered from the AP, the AP does not need to inform other STAs that RSPs related to P2P operations are deferred.

[0313] Thereafter, when RSP STA 1 attempts to transmit and receive data to and from RSP STA 2 in the r-TWT SP (i.e., when it attempts to resume the r-TWT SP associated with the P2P operation), RSP STA 1 sets the value of the next TWT subfield to the desired time (i.e., T resume ), set the value of the P2P subfield to 1, and send TWT information to the AP.

[0314] As a specific example, in relation to the r-TWT information frame that RSP STA 1 sends to the AP, the value of the restricted TWT subfield is set to 1, the value of the broadcast TWT ID subfield is set to 2, the value of the all TWT subfield is set to 1, and the value of the next TWT subfield is set to T resume (e.g., the start time of RSP #3).

[0315] In response to the TWT information, the RSP STA 1 can receive an ACK from the AP. The RSP STA 1 that receives the ACK can receive the ACK at time T resume After that, data transmission and reception between RSP STA 1 and RSP STA 2 can be performed from RSP #3, which is the subsequently assigned r-TWT SP (i.e., the next r-TWT SP). That is, the P2P operation between RSP STA 1 and RSP STA 2 is performed for a period of time T resume From now on, the r-TWT SP assigned to the RSP STA 1 may be used for resuming communication. In this case, frames may be transmitted and received between the RSP STA 1 and the RSP STA 2 in the r-TWT SP. As an example, in RSP #3, the RSP STA 1 may transmit an MU-RTS to the RSP STA 2, and the RSP STA 2 may transmit a CTS to the RSP STA 1.

[0316] The AP that has received the above TWT information can inform the RSP STAs having the same broadcast TWT ID that the RSP will be resumed. For example, the AP can inform the RSP STAs (including RSP STA 2) that have been assigned the r-TWT SP together with the RSP STA 1, i.e., have the same broadcast TWT ID, that the P2P operation in the r-TWT SP performed by the RSP STA 1 will be resumed, using a management frame such as a beacon frame.

[0317] The RSP STA 2 that receives such information resume After that, data transmission and reception (particularly P2P transmission and reception) can be performed from the first RSP, RSP #3.

[0318] Additionally or alternatively, the AP may provide information to RSP STA 2 to trigger P2P operation without informing other STAs that the RSP associated with P2P operation is being resumed.

[0319] In relation to the r-TWT information frame / field in FIG. 21 described above, the restricted TWT subfield and the P2P subfield can be expressed as one subfield.

[0320] FIG. 24 illustrates another example of an r-TWT related information frame according to the present disclosure.

[0321] Referring to FIG. 24, the restricted TWT subfield and the P2P subfield in FIG. 21 may be (integrally) expressed as a TWT identifier subfield.

[0322] For example, the r-TWT information frame (or r-TWT information field) may include a 2-bit TWT identifier subfield, a 5-bit broadcast TWT ID subfield, a 1-bit all TWT subfield, a 2-bit next TWT subfield size subfield, and a 0 / 32 / 48 / 64-bit next TWT subfield.

[0323] The TWT identifier subfield may indicate / distinguish information regarding whether the scheduled TWT SP is for a broadcast TWT, a restricted TWT, or for P2P operation within a restricted TWT.

[0324] For example, a value of 0 in the TWT identifier subfield may indicate that the scheduled TWT SP is for a broadcast TWT. A value of 1 in the TWT identifier subfield may indicate that the scheduled TWT SP is for UL / DL data transmission and reception in a restricted TWT. A value of 2 in the TWT identifier subfield may indicate that the scheduled TWT SP is for data transmission and reception based on P2P operation in a restricted TWT. When the value of the TWT identifier subfield is set to 3, it may be reserved.

[0325] Additionally or alternatively, in relation to the r-TWT information frame / field in FIG. 21 described above, it may also be considered that the restricted TWT subfield is not included.

[0326] FIG. 25 illustrates yet another example of an r-TWT related information frame according to the present disclosure.

[0327] Referring to FIG. 25, the restricted TWT subfield in FIG. 21 may be excluded from the r-TWT information frame / field.

[0328] For example, the r-TWT information frame (or r-TWT information field) may include a 5-bit broadcast TWT ID subfield, a 1-bit P2P subfield, a 1-bit all TWT subfield, a 2-bit next TWT subfield size subfield, and a 0 / 32 / 48 / 64-bit next TWT subfield.

[0329] In this case, the r-TWT information frame does not indicate whether the TWT SP is for a restricted TWT, and therefore can only transmit information on the TWT SP that corresponds to the r-TWT SP.

[0330] That is, the r-TWT information frame / field in FIG. 21 may include / convey information regarding the broadcast TWT SP, whereas the r-TWT information frame / field in FIG. 25 may be designed / defined to include / convey only information regarding the r-TWT SP.

[0331] Additionally or alternatively, a response requested subfield and a next TWT request subfield may be added in relation to the r-TWT information frame / field in FIG. 21 described above.

[0332] FIG. 26 illustrates yet another example of an r-TWT related information frame according to the present disclosure.

[0333] Referring to FIG. 26, a response requested subfield and a next TWT request subfield may be included in the r-TWT information frame / field in FIG.

[0334] For example, the r-TWT information frame (or r-TWT information field) may include a 1-bit restricted TWT subfield, a 5-bit broadcast TWT ID subfield, a 1-bit response requested subfield, a 1-bit next TWT request subfield, a 1-bit P2P subfield, a 1-bit all TWT subfield, a 2-bit next TWT subfield size subfield, and a 0 / 32 / 48 / 64-bit next TWT subfield.

[0335] The response requested subfield can be set to 1 or 0 to indicate whether or not a response is required upon receipt of the TWT information frame.

[0336] That is, the response requested subfield may indicate whether the transmitting end of the frame including the TWT information field requests the transmitting end to transmit a TWT information frame in response to the frame. The response requested subfield may be set to 0 to request the receiving end not to transmit a TWT information frame in response to the frame. The response requested subfield may be set to 1 to request the receiving end to transmit a TWT information frame in response to the frame.

[0337] The next TWT request subfield may be set to 1 or 0 to indicate whether or not there is a request to receive a TWT information frame including a next TWT subfield set to a value greater than 0. That is, the next TWT Request subfield may be set to 1 to indicate that the TWT information frame is a request to transmit a TWT information frame including a next TWT field with a length other than 0. Otherwise, the next TWT Request subfield may be set to 0.

[0338] Example 2

[0339] In the above-mentioned embodiment 1, the r-TWT related information frame / field for indicating the suspension / resume of the r-TWT SP and the presence or absence of P2P operation has been described.

[0340] In this regard, the present embodiment proposes a method for defining / designing a TWT information frame / field by further considering information regarding the extension / extension of the r-TWT SP.

[0341] For example, the subfields associated with the extension / extension of the r-TWT SP may be designed / defined so that they can be included in the r-TWT information frames / fields in Figures 21, 24, 25 and / or 26 described above.

[0342] FIG. 27 illustrates yet another example of an r-TWT related information frame according to the present disclosure.

[0343] 27, the r-TWT information frame / field in FIG. 21 may further include a subfield related to the extension of the r-TWT SP, i.e., a restricted TWT SP extension subfield.

[0344] For example, the r-TWT information frame (or r-TWT information field) may include a 1-bit restricted TWT subfield, a 5-bit broadcast TWT ID subfield, a 1-bit P2P subfield, a 1-bit restricted TWT SP extension subfield, a 1-bit all TWT subfield, a 2-bit next TWT subfield size subfield, and a 0 / 32 / 48 / 64-bit next TWT subfield.

[0345] The restricted TWT SP extension subfield may contain information regarding the extension / extension of the end time of the initialized r-TWT SP.

[0346] For example, when a STA transmits an r-TWT information frame to an AP with the value of the restricted TWT SP extension subfield set to 1, this may mean that the STA has transmitted a request to the AP to extend the end point of the currently ongoing r-TWT SP. In this case, the value of next TWT in the r-TWT information frame is set to a value greater than 0 (e.g., T end ) can mean that a specific end point is specified.

[0347] In the examples according to the present disclosure, T end may correspond to an extended end time and may have a value based on the TSF.

[0348] As another example, when an AP sends an r-TWT information frame to a STA with the value of the restricted TWT SP extension subfield set to 1, this may mean that the AP announces that it has extended the end point of the currently ongoing r-TWT SP to the value of the next TWT subfield.

[0349] In both of the above examples, the duration from the start time of the postponed r-TWT SP to the end time of the extended r-TWT SP does not exceed the duration of the r-TWT SP initially scheduled by the AP. Additionally or alternatively, when the r-TWT SP is extended, it does not overlap (i.e., overlap) with any subsequently scheduled TWT SP.

[0350] In view of this, if at least one of the following two cases is met, the AP must reject the STA's request for an extension of the r-TWT SP.

[0351] Case 1. The STA requests that the end of the r-TWT SP be extended to have a longer duration than the duration of the r-TWT SP initially scheduled by the AP.

[0352] - Case 2. The STA's extension request for an r-TWT SP overlaps (i.e., overlaps) with a TWT SP scheduled after the current r-TWT SP.

[0353] In this regard, in order to confirm / convey that the STA's extension request for the r-TWT SP is valid, the AP may need to send an ACK for the extension request to the STA. From the ACK, the STA can confirm that the extension request for the r-TWT SP has been accepted / permitted by the AP and the end point of the r-TWT SP has been extended.

[0354] In relation to a specific value of the restricted TWT SP extension subfield, the following may be indicated based on the above-mentioned all TWT subfield, next TWT subfield, and restricted TWT SP extension subfield.

[0355] For example, a value of the all TWT subfield set to 1, a value of the next TWT subfield set to 0, and a value of the restricted TWT SP extension subfield set to 0 may indicate / mean a hiatus for the r-TWT SP. resume ), and the value of the restricted TWT SP extension subfield is set to 0, the value of the next TWT subfield (i.e., T resume ) to restart the r-TWT SP from the first r-TWT SP allocated after the last TWT SP. The value of the all TWT subfield is set to 1 and the value of the next TWT subfield is set to a value greater than 0 (e.g., T end ), and the value of the restricted TWT SP extension subfield is set to 1, the value of the next TWT subfield (i.e., T end ) can indicate / mean the end point for the extended r-TWT SP. The value of the all TWT subfield is set to 0 and the value of the next TWT subfield is set to a value greater than 0 (e.g., T end ), and the value of the restricted TWT SP extension subfield is set to 1, the value of the next TWT subfield (i.e., T end ) can indicate / mean the end point requested (by the STA to the AP) for the extended r-TWT SP.

[0356] In the following, with reference to FIG. 28 and FIG. 29, the operation between the r-TWT scheduling AP and the r-TWT scheduled STA based on the r-TWT related information frame will be described in consideration of the above-mentioned extended r-TWT SP.

[0357] 28 and 29, the TWT information may be transmitted or received in the form of a TWT information frame, which may correspond to or include the r-TWT information frame / field described above.

[0358] FIG. 28 illustrates an example of limited TWT operation taking into account an extended r-TWT SP according to the present disclosure.

[0359] Referring to FIG. 28, a signaling method of TWT information in the case where an extended r-TWT SP occurs by a STA that does not support r-TWT (i.e., does not belong to an r-TWT SP) is illustrated.

[0360] First, the AP can notify STAs to which an r-TWT SP is assigned of r-TWT-related information using a management frame such as a beacon frame, where the r-TWT-related information may include RSP assignment information.

[0361] As mentioned above, the TXOP of a STA that does not belong to an r-TWT SP must be stopped before any r-TWT SP can be started. For example, the TXOP of non-RSP STA 2 must be aborted because it does not belong to the RSP. However, if the TXOP of non-RSP STA 2 does not need to prioritize the r-TWT SP, such as for latency-sensitive traffic, the start point of the r-TWT SP may be delayed, and thus the end point of the r-TWT SP may also be delayed. This can be referred to as an extended r-TWT SP.

[0362] In the example of Figure 28, the extended RSP occurs due to the TXOP of non-RSP STA 2, and the TWT information transmitted by the AP can be used to indicate that the originally assigned RSP is extended. In this case, the length of the originally assigned RSP must be greater than or equal to the length of the extended RSP.

[0363] As a specific example, in relation to the r-TWT information frame transmitted by the AP, the value of the restricted TWT subfield is set to 1, the value of the restricted TWT SP extension subfield is set to 1, the value of the all TWT subfield is set to 1, and the value of the next TWT subfield is set to T end In other words, the AP may set the value of the restricted TWT SP extension subfield to 1 to indicate that the current r-TWT SP is extended, and set the value of the next TWT subfield to T end can indicate the end point of the extended r-TWT SP.

[0364] If the r-TWT SP is assigned to various STAs on a broadcast TWT basis, the receiver address (RA) field of the TWT information may be set to a broadcast address and transmitted in a broadcast manner.

[0365] The RSP STA (e.g., RSP STA 1) that receives the ACK for the above TWT information determines that the end point of the r-TWT SP is T end Data transmission and reception within the RSP can be performed based on the extension of the time.

[0366] FIG. 29 illustrates another example of limited TWT operation considering an extended r-TWT SP according to the present disclosure.

[0367] Referring to Figure 29, a signaling method for TWT information is illustrated when an extended r-TWT SP occurs by a STA that does not support r-TWT (i.e., does not belong to an r-TWT SP) and P2P operation between RSP STAs is taken into consideration.

[0368] First, the AP may announce r-TWT-related information to a STA to which an r-TWT SP is assigned using a management frame such as a beacon frame. Here, the r-TWT-related information may include RSP assignment information, etc. Additionally or alternatively, the r-TWT SP may be configured for P2P transmission / reception, or P2P transmission / reception may be performed within a TXOP specified by separate signaling for P2P transmission / reception within the r-TWT SP (e.g., P2P assisted mode of a triggered TXOP sharing procedure).

[0369] In order to obtain the same membership as the RSP included in a management frame such as a beacon frame, the RSP STA 2 can send a TWT request to the AP specifying the same broadcast TWT ID value and setting the negotiation type value to 3.

[0370] In response to the TWT request, the AP may set the TWT setup command as the allowed TWT and send a TWT response to the RSP STA 2.

[0371] As mentioned above, the TXOP of a STA that does not belong to an r-TWT SP must be stopped before any r-TWT SP is started. For example, the TXOP of non-RSP STA3 must be aborted because it does not belong to the RSP. However, if the TXOP of non-RSP STA3 does not need to prioritize the r-TWT SP, such as for latency-sensitive traffic, the start time of the r-TWT SP may be delayed, which may also delay the end time of the r-TWT SP.

[0372] In the example of Figure 29, the extended RSP occurs due to the TXOP of non-RSP STA3, and the TWT information transmitted by the AP can be used to indicate that the originally assigned RSP is extended. In this case, the length of the originally assigned RSP must be greater than or equal to the length of the extended RSP.

[0373] As a specific example, in relation to the r-TWT information frame transmitted by the AP, the value of the restricted TWT subfield is set to 1, the value of the broadcast TWT ID subfield is set to 3, the value of the P2P subfield is set to 1, the value of the restricted TWT SP extension subfield is set to 1, the value of the all TWT subfield is set to 1, and the value of the next TWT subfield is set to T end In other words, the AP may set the value of the restricted TWT SP extension subfield to 1 to indicate that the current r-TWT SP in which data is transmitted and received between RSP STA 1 and RSP STA 2 is extended, and set the value of the next TWT subfield to T end can be used to indicate the end point of the extended r-TWT SP.

[0374] If the r-TWT SP is assigned to various STAs on a broadcast TWT basis, the receiver address (RA) field of the TWT information may be set to a broadcast address and transmitted in a broadcast manner.

[0375] The RSP STA (e.g., RSP STA 1) that receives the ACK for the above TWT information determines that the end point of the r-TWT SP is T end Based on this extension, data transmission and reception can be performed through P2P operations within the RSP.

[0376] FIG. 30 is a diagram for explaining the operation of a STA that supports rescheduling of an r-TWT SP according to an embodiment of the present disclosure.

[0377] FIG. 30 illustrates the operation of the STA based on the previously proposed method (eg, any one of the above-mentioned embodiment 1, embodiment 2, and their detailed embodiments, or a combination of one or more (detailed) embodiments).

[0378] In step S3010, the STA may establish an r-TWT related agreement.

[0379] Here, the r-TWT related agreement may be established between the AP STA and the non-AP STA. As an example, as described above, the r-TWT related agreement may be established based on the exchange of a TWT request and a TWT response.

[0380] In relation to the r-TWT-related agreement, if the STA is a non-AP STA, the STA may receive r-TWT SP-related allocation information from an AP STA via a management frame such as a beacon frame. Alternatively, if the STA is an AP STA, the STA may transmit r-TWT SP-related allocation information to a non-AP STA using a management frame such as a beacon frame.

[0381] In step S3020, the STA may transmit at least one frame including a TWT information field to one or more other STAs.

[0382] If the STA is a non-AP STA, one or more of the other STAs may be AP STAs.

[0383] If the STA is an AP STA, the one or more other STAs may be one or more non-AP STAs.

[0384] Here, the frame including the TWT information field may be a TWT information frame, for example, the at least one frame may include another TWT information frame defined for r-TWT, or may include an existing TWT information frame.

[0385] As per the embodiment of the present disclosure, the TWT information field may include an r-TWT related subfield, an all TWT subfield, and a next TWT subfield.

[0386] Rescheduling-related information for an r-TWT SP scheduled for the STA (or a currently existing r-TWT SP) may be indicated based on the r-TWT-related subfields, all TWT subfields and next TWT subfield in the TWT information field transmitted by the STA.

[0387] Here, the rescheduling related information may include one or more of information regarding the presence or absence of a suspension of the r-TWT SP, information regarding the resumption point of the r-TWT SP, and information regarding the end point of the extended r-TWT SP.

[0388] Based on the combination of the r-TWT related subfields and the all TWT subfields, the rescheduling target may be indicated / confirmed. For example, a specific combination of the value of the r-TWT related subfields and the value of the all TWT subfields may indicate the suspension of all r-TWT SPs scheduled for the STA.

[0389] For example, the r-TWT related subfield may indicate whether the TWT SP to be rescheduled corresponds to an r-TWT SP. As a specific example, the r-TWT related subfield may indicate whether the currently existing or rescheduled TWT SP corresponds to an r-TWT SP or a broadcast TWT SP.

[0390] For example, the TWT information field may further include a Broadcast TWT ID subfield. If the rescheduled TWT SP corresponds to an r-TWT SP, the Broadcast TWT ID subfield may indicate TWT membership for one or more STAs supporting the r-TWT SP.

[0391] Additionally or alternatively, for all TWT subfields having the same value (e.g., set to 1), the value of the next TWT subfield may indicate whether an r-TWT SP is suspended or not, or may indicate restart timing information (e.g., a restart timing reference). For example, for all TWT subfields set to a value of 1, a next TWT subfield set to a value of 0 may indicate suspension, and a next TWT subfield set to a value greater than 0 may indicate restart timing information, where the restart timing information may correspond to the first r-TWT SP after the next TWT subfield value.

[0392] Additionally or alternatively, the TWT information field may further include a subfield (e.g., a P2P subfield) indicating a type of the r-TWT SP, where the type of the r-TWT SP may include a first type for UL / DL transmission / reception between an AP STA and a non-AP STA, and a second type for P2P transmission / reception between non-AP STAs.

[0393] Additionally or alternatively, the TWT information field may further include an extension-related subfield (eg, a restricted TWT SP extension subfield) indicating whether the end point of the r-TWT SP scheduled for the STA is extended.

[0394] In this regard, extension / resumption related information of the r-TWT SP may be indicated based on the value of the subfield and the value of the next TWT subfield (and the values ​​of all TWT subfields).

[0395] For example, if all TWT subfields are set to 1 and the next TWT subfield is set to a value greater than 0, an extension-related subfield set to a first value (e.g., value 0) may indicate a restart at the first r-TWT SP after the value of the next TWT subfield. On the other hand, if all TWT subfields are set to 1 and the next TWT subfield is set to a value greater than 0, an extension-related subfield set to a second value (e.g., value 1) may indicate / inform that the end point is extended to the value of the next TWT subfield. This may be the case when the TWT information field is transmitted by an AP STA to a non-AP STA.

[0396] As another example, when all TWT subfields are set to 0 and the next TWT subfield is set to a value greater than 0, an extension-related subfield set to a specific value (e.g., 1) may indicate / mean a request to extend the end point of the r-TWT SP to the value of the next TWT subfield. This may be the case when the TWT information field is transmitted by a non-AP STA to an AP STA. In this regard, if certain conditions are not met, the request must be rejected by the AP STA. As an example, if at least one of the following applies: the duration of the extended r-TWT SP exceeds the duration of the r-TWT SP initially scheduled for the STA, or the extended r-TWT SP overlaps with a subsequent TWT SP, the request is rejected and the AP STA may transmit information regarding the rejection to the non-AP STA.

[0397] In the above disclosure, the definition / design of a TWT information frame / field including information related to an r-TWT SP as new TWT information for an r-TWT SP and a signaling method based thereon have been described.

[0398] In this regard, the r-TWT information frame proposed in the present disclosure may be applied / utilized by defining a new TWT information frame, or may be applied / utilized based on an existing TWT information frame, in addition or as an alternative.

[0399] For example, a new TWT information frame for restricted TWTs may be transmitted or received in addition to the existing TWT information frame to indicate / convey the above-mentioned r-TWT SP related information.

[0400] As another example, the new TWT information for the r-TWT SP may be configured / defined based on the existing TWT information frame but in the form of a new TWT information field. As a specific example, in the existing TWT information frame, a new TWT information field (i.e., an additional / extended TWT information field) may be included following the existing TWT information field. That is, apart from the existing TWT information field (e.g., the TWT information field format of FIG. 16), the new TWT information field may include subfields associated with the r-TWT SP as described above in this disclosure. In this case, the information associated with the r-TWT SP may be indicated based on the new TWT information field or a combination of the existing TWT information field and the new TWT information field.

[0401] The above-described embodiments are combinations of the components and features of the present disclosure in a predetermined form. Each component or feature should be considered as optional unless otherwise expressly stated. Each component or feature may be implemented in a form not combined with other components or features. It is also possible to combine some components and / or features to configure the embodiments of the present disclosure. The order of operations described in the embodiments of the present disclosure may be changed. Some configurations or features of one embodiment may be included in another embodiment, or may be replaced with corresponding configurations or features of another embodiment. It is clear that claims that do not have an explicit reference relationship in the claims may be combined to configure an embodiment, or may be included as a new claim by amendment after filing.

[0402] It is obvious to those skilled in the art that the present disclosure can be embodied in other specific forms without departing from the essential features of the present disclosure. Therefore, the above detailed description should not be interpreted as limiting in any respect, but should be considered as illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the attached claims, and any modifications within the equivalent scope of the present disclosure are included in the scope of the present disclosure.

[0403] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that cause a device or computer to perform operations according to the methods of various embodiments, and non-transitory computer-readable media on which such software or instructions or the like can be stored and executed on a device or computer. Instructions available for programming a processing system to perform features described in the present disclosure may be stored on / in a storage medium or computer-readable storage medium, and computer program products including such storage media may be used to embody features described in the present disclosure. The storage medium may include high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid-state memory devices, but is not limited thereto, and may include non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory optionally includes one or more storage devices that are located remotely from the processor. The memory or alternatively the non-volatile memory devices in the memory include non-transitory computer-readable storage media. The features described in this disclosure may be embodied in software and / or firmware stored on any one of a number of machine-readable media and capable of controlling the hardware of a processing system and allowing the processing system to interact with other mechanisms that utilize the results of embodiments of the present disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers. [Industrial Applicability]

[0404] The method proposed in this disclosure has been described mainly as being applied to an IEEE 802.11-based system, but it can also be applied to various wireless LANs or wireless communication systems other than the IEEE 802.11-based system.

Claims

1. A method performed by a station (STA) in a wireless LAN system, the method comprising: establishing an agreement relating to a restricted-target wake time (r-TWT); transmitting at least one frame including a TWT information field to one or more other STAs; The TWT information field includes an r-TWT related subfield, an all TWT subfield, and a next TWT subfield; The method of claim 1, wherein rescheduling-related information for a r-TWT service period (r-TWT SP) scheduled for the STA is indicated based on the r-TWT-related subfield, the all TWT subfield, and the next TWT subfield.

2. The method of claim 1, wherein a particular combination of the value of the r-TWT-related subfield and the value of the all TWT subfield indicates suspension of all r-TWT SPs scheduled for the STA.

3. The method of claim 1 , wherein the r-TWT-related subfield indicates whether the rescheduled TWT SP corresponds to an r-TWT SP.

4. The TWT information field further includes a Broadcast TWT ID subfield; The method of claim 3, wherein the broadcast TWT ID subfield indicates TWT membership for one or more STAs supporting the r-TWT SP based on the fact that the rescheduled TWT SP corresponds to an r-TWT SP.

5. For the same values ​​of all the TWT subfields, the Next TWT subfield set to a zero value indicates an interrupt; 2. The method of claim 1, wherein the next TWT subfield set to a value greater than 0 indicates resume timing information.

6. The method of claim 5 , wherein the restart timing information corresponds to a first r-TWT SP after the next TWT subfield value.

7. The TWT information field further includes a subfield indicating a type of the r-TWT SP, The method of claim 1, wherein the types of the r-TWT SP include a first type for uplink or downlink transmission / reception between an access point (AP) STA and a non-AP (non-AP) STA, and a second type for P2P transmission / reception between non-AP STAs.

8. The method of claim 1, wherein the TWT information field further includes an extension-related subfield indicating whether an end timing of an r-TWT SP scheduled for the STA is extended.

9. based on the Next TWT subfield being set to a value greater than 0, The extension related subfield set to a first value indicates a resume at the first r-TWT SP after the value of the next TWT subfield; The method of claim 8 , wherein the extension related subfield set to a second value indicates that an end point is extended to the value of the next TWT subfield.

10. Based on the fact that the STA is a non-AP STA to be r-TWT scheduled and the one or more other STAs are AP STAs, 9. The method of claim 8, wherein the extension related subfield is set to a particular value and the next TWT subfield is set to a value greater than zero to indicate a request to extend the end point to the value of the next TWT subfield.

11. The AP STA determines whether or not to reject the request based on at least one of a first condition or a second condition; The first condition corresponds to whether the duration of the extended r-TWT SP exceeds the duration of the r-TWT SP initially scheduled for the STA; The method of claim 10, wherein the second condition corresponds to whether the extended r-TWT SP overlaps with a subsequent existing TWT SP.

12. A station (STA) device of a wireless LAN system, the STA device comprising: one or more transceivers; one or more processors coupled to the one or more transceivers; The one or more processors: Establish an agreement related to restricted-target wake time (r-TWT); configured to transmit at least one frame including a TWT information field to one or more other STAs; The TWT information field includes an r-TWT related subfield, an all TWT subfield, and a next TWT subfield; Rescheduling-related information for an r-TWT service period (r-TWT SP) scheduled for the STA is indicated based on the r-TWT-related subfield, the all TWT subfield, and the next TWT subfield.

13. 1. A processing unit configured to control a station (STA) in a wireless LAN system, the processing unit comprising: one or more processors; and one or more computer memories operably coupled to the one or more processors and storing instructions for performing the method according to any one of claims 1 to 11 when executed by the one or more processors.

14. One or more non-transitory computer-readable media storing one or more instructions, The one or more instructions are executed by one or more processors, and a station (STA) device in a wireless LAN system to perform the method according to any one of claims 1 to 11.

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