Method and apparatus for executing restricted target waketime-based communication in a wireless LAN system

Abstract

A method and apparatus for communicating in a wireless LAN system by a first station (STA) is disclosed, the method includes: performing a restricted target wake time (r-TWT) membership setup procedure with a second STA; and receiving r-TWT schedule information included in a broadcast TWT element from the second STA, and the first TXOP may end before a start time of the r-TWT SP based on a certain portion of a first transmission opportunity (TXOP) in an r-TWT service period (SP) announced by the r-TWT schedule information being not used to transmit a DL frame corresponding to at least one r-TWT downlink (DL) traffic identifier (TID) or to request a UL frame corresponding to at least one r-TWT uplink (UL) TID.

Description

[Technical Field]

[0001] The present disclosure relates to a communication execution method and apparatus in a wireless local area network (WLAN) system, and more particularly, to a restricted target wake time (TWT)-based communication execution method and apparatus in a next-generation WLAN system. [Background Art]

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

[0003] In order to provide an improved wireless communication environment, improvement technologies for EHT (Extremely High Throughput) have been discussed. For example, technologies for increased bandwidth, efficient utilization of multiple bands, multiple-input multiple-output (MIMO) supporting an increased number of spatial streams, and coordination between multiple access points (APs) have been studied, and in particular, various technologies have been studied to support traffic with low latency or real-time characteristics. [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] The technical problem addressed by this disclosure is to provide a method and apparatus for transmitting latency-sensitive data / traffic in a wireless LAN system.

[0005] A further technical challenge of this disclosure is to provide a method and apparatus for implementing the conditional r-TWT SP (service period) TXOP rule in a wireless LAN system.

[0006] The technical challenges addressed in this disclosure are not limited to those mentioned above, and other technical challenges not mentioned will be clearly understood by those with ordinary skill in the art to which this disclosure pertains from the following description. [Means for solving the problem]

[0007] A method for communicating by a first STA in a wireless LAN system according to one aspect of this disclosure includes the steps of performing a restricted target wake time (r-TWT) membership setup procedure with a second STA, and receiving r-TWT schedule information contained in a broadcast TWT element from the second STA, wherein the r-TWT schedule information Announcement Based on the fact that a particular portion of the first transmission opportunity (TXOP) within the r-TWT service period (SP) is not used for transmitting DL frames corresponding to at least one r-TWT downlink (DL) traffic identifier (TID) or requesting UL frames corresponding to at least one r-TWT uplink (UL) TID, the first TXOP may terminate before the start time of the r-TWT SP.

[0008] A method for communicating by a second STA in a wireless LAN system according to one aspect of this disclosure includes the steps of performing a restricted target wake time (r-TWT) membership setup procedure with the first STA, and transmitting r-TWT schedule information contained in a broadcast TWT element to the first STA, wherein the r-TWT schedule information Announcement Based on the fact that a particular portion of the first transmission opportunity (TXOP) within the r-TWT service period (SP) is not used for transmitting DL frames corresponding to at least one r-TWT downlink (DL) traffic identifier (TID) or requesting UL frames corresponding to at least one r-TWT uplink (UL) TID, the first TXOP may terminate before the start time of the r-TWT SP. [Effects of the Invention]

[0009] This disclosure provides a method and apparatus for transmitting latency-sensitive data / traffic in a wireless LAN system.

[0010] According to this disclosure, a method and apparatus for implementing a conditional r-TWT SP(service period)TXOP rule in a wireless LAN system can be provided.

[0011] According to this disclosure, the r-TWT SP TXOP rule can improve the efficiency of latency-sensitive data / traffic transmission in a manner that does not interfere with existing data transmission and reception flows, in addition to providing the intended predictable low-latency service.

[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 from the following description by a person having ordinary knowledge in the technical field to which the present disclosure pertains. [Brief Description of the Drawings]

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

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

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

[0016] [Figure 3] FIG. 3 is a diagram for explaining a link setup process to which the present disclosure can be applied.

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

[0018] [Figure 5] FIG. 5 is a diagram for explaining a CSMA / CA-based frame transmission operation to which the present disclosure can be applied.

[0019] [Figure 6] 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.

[0020] [Figure 7] 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.

[0021] [Figure 8-10] FIG. 1 is a diagram for explaining an example of resource units in a wireless LAN system to which the present disclosure is applicable.

[0022] [Figure 11] FIG. 2 is a diagram illustrating an exemplary structure of an HE-SIG-B field.

[0023] [Figure 12] FIG. 3 is a diagram for explaining an MU-MIMO scheme in which a plurality of users / STAs are allocated to one RU.

[0024] [Figure 13] FIG. 4 is a diagram illustrating an example of a PPDU format to which the present disclosure is applicable.

[0025] [Figure 14] FIG. 5 is a diagram for explaining an example of individual TWT operation to which the present disclosure is applicable.

[0026] [Figure 15] FIG. 6 is a diagram for explaining an example of broadcast TWT operation to which the present disclosure is applicable.

[0027] [Figure 16] FIG. 7 is a diagram for explaining an example of a TWT information element format.

[0028] [Figure 17] FIG. 8 is a diagram for explaining an example of an individual TWT parameter set field format.

[0029] [Figure 18] FIG. 9 is a diagram for explaining an example of a broadcast TWT parameter set field format.

[0030] [Figure 19] FIG. 10 is a diagram for explaining restricted TWT operation of an STA according to an example of the present disclosure.

[0031] [Figure 20] This is a diagram illustrating the restricted TWT operation of the first STA in an example of this disclosure.

[0032] [Figure 21] This is a diagram illustrating the restricted TWT operation of the second STA in an example of this disclosure.

[0033] [Figure 22-25] This diagram illustrates the process by which the conditional TXOP rule is applied to an r-TWT SP as an example of this disclosure.

[0034] [Figure 26-28] This diagram illustrates an example of the process by which an AP informs other STAs of information regarding r-TWT, as described in this disclosure. [Modes for carrying out the invention]

[0035] Preferred embodiments relating to this disclosure will be described in detail below with reference to the accompanying drawings. The detailed description disclosed below, together with the accompanying drawings, is intended to illustrate exemplary embodiments of this disclosure and is not intended to represent the only possible embodiments of this disclosure. The detailed description below includes specific details to provide a complete understanding of this disclosure. However, those skilled in the art will understand that this disclosure is implementable without such specific details.

[0036] In some cases, to avoid ambiguity of the concepts in this disclosure, known structures and devices may be omitted, or they may be shown in the form of block diagrams focusing on the core function of each structure and device.

[0037] In this disclosure, when one component is “connected,” “joined,” or “linked” to another component, this may include not only a direct connection but also an indirect connection in which other components exist between them. Also, in this disclosure, the terms “includes” or “have” identify the presence of the referred features, stages, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, stages, operations, elements, components and / or groups thereof.

[0038] In this disclosure, terms such as "first," "second," etc., are used solely to distinguish one component from another, and are not used to limit the components, nor do they limit the order or importance of the components unless specifically mentioned. 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.

[0039] The terms used in this disclosure are for illustrative purposes relating to specific embodiments and are not intended to limit the scope of the claims. As used in the description of the embodiments and in the attached claims, singular forms are intended to include plural forms unless otherwise specified in the context. The terms "and / or" used in this disclosure may refer to one of the related enumerated items, or to any and all possible combinations of two or more of them. In this disclosure, a " / " between words has the same meaning as "and / or" unless otherwise specified.

[0040] The examples in this disclosure may be applied to a variety of wireless communication systems. For example, the examples in this disclosure may be applied to wireless LAN systems. For example, the examples in this disclosure may be applied to IEEE 802.11a / g / n / ac / ax standard-based wireless LANs. Furthermore, the examples in this disclosure may be applied to newly proposed IEEE 802.11be (or EHT) standard-based wireless LANs. The examples in this disclosure may be applied to IEEE 802.11be release-2 standard-based wireless LANs, which represent further improvements to the IEEE 802.11be release-1 standard. In addition, the examples in this disclosure may be applied to next-generation standard-based wireless LANs following IEEE 802.11be. Moreover, the examples in this disclosure may be applied to cellular wireless communication systems. For example, they may be applied to cellular wireless communication systems based on 3GPP® (3rd Generation Partnership Project) standard LTE (Long Term Evolution) series technologies and 5G NR (New Radio) series technologies.

[0041] The following describes the technical features to which the examples in this disclosure may apply.

[0042] Figure 1 is a block diagram illustrating an example of a wireless communication device according to one embodiment of the present disclosure.

[0043] The first device 100 and the second device 200 illustrated in Figure 1 may be replaced with various terms such as terminal, wireless device, WTRU (Wireless Transmit Receive Unit), UE (User Equipment), MS (Mobile Station), UT (user terminal), MSS (Mobile Subscriber Station), MSS (Mobile Subscriber Unit), SS (Subscriber Station), AMS (Advanced Mobile Station), WT (Wireless terminal), or simply user. Furthermore, the first device 100 and the second device 200 may be replaced with various terms such as access point (AP), BS (Base Station), fixed station, Node B, BTS (base transceiver system), network, AI (Artificial Intelligence) system, RSU (roadside unit), repeater, router, relay, gateway, etc.

[0044] The devices 100 and 200 illustrated in Figure 1 can also be referred to as stations (STA). For example, the devices 100 and 200 illustrated in Figure 1 can be referred to by various terms such as transmitting device, receiving device, transmitting STA, and receiving STA. For example, STA 110 and 200 can play the role of an AP (access point) or a non-AP. That is, in this disclosure, STA 110 and 200 may have AP and / or non-AP functions. When STA 110 and 200 have AP functions, they can simply be called APs, and when STA 110 and 200 have non-AP functions, they can simply be called STAs. In addition, in this disclosure, AP may be represented as AP STA.

[0045] Referring to Figure 1, the first device 100 and the second device 200 can send and receive wireless signals using various wireless LAN technologies (e.g., the IEEE 802.11 series). The first device 100 and the second device 200 may include interfaces to the medium access control (MAC) layer and the physical layer (PHY) in accordance with the IEEE 802.11 standard.

[0046] Furthermore, the first device 100 and the second device 200 can also further support various communication standards other than Wi-Fi technology (e.g., 3GPP LTE series, 5G NR series standards, etc.). The devices of this disclosure may also be embodied in various devices such as mobile phones, vehicles, personal computers, Augmented Reality (AR) equipment, and Virtual Reality (VR) equipment. In addition, the STA of this specification can support various communication services such as voice calls, video calls, data communication, autonomous driving, Machine-Type Communication (MTC), Machine-to-Machine (M2M), Device-to-Device (D2D), and Internet of Things (IoT).

[0047] 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 control the memories 104 and / or the transceivers 106 and be configured to embody the descriptions, functions, procedures, suggestions, methods and / or operation diagrams of this disclosure. For example, the processor 102 may process information in the memory 104 to generate first information / signals and then transmit a radio signal containing the first information / signals via the transceiver 106. Alternatively, the processor 102 may receive a radio signal containing second information / signals via the transceiver 106 and then store information obtained from signal processing of the second information / signals in the memory 104. The memory 104 may be linked to the processor 102 and can store various information relating to the operation of the processor 102. For example, memory 104 may store software code that executes some or all of a process controlled by processor 102, or that contains instructions for executing the descriptions, functions, procedures, suggestions, methods and / or operation sequence diagrams in this disclosure. Here, processor 102 and memory 104 may be part of a communication modem / circuit / chip designed to embody wireless LAN technology (e.g., IEEE 802.11 series). Transceiver 106 may be coupled with processor 102 and can transmit and / or receive radio signals via one or more antennas 108. Transceiver 106 may include a transmitter and / or receiver. Transceiver 106 may be used synonymously with RF (Radio Frequency) unit. In this disclosure, device may also mean communication modem / circuit / chip.

[0048] The second device 200 includes 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 control the memories 204 and / or the transceivers 206 and be configured to embody the descriptions, functions, procedures, suggestions, methods and / or operation sequence diagrams disclosed herein. For example, the processor 202 may process information in the memory 204 to generate third information / signals and then transmit a radio signal containing the third information / signals via the transceiver 206. Alternatively, the processor 202 may receive a radio signal containing fourth information / signals via the transceiver 206 and then store information obtained from signal processing of the fourth information / signals in the memory 204. The memory 204 may be linked to the processor 202 and can store various information related to the operation of the processor 202. For example, memory 204 may store software code that executes some or all of the processes controlled by processor 202, or that contains instructions for executing the descriptions, functions, procedures, suggestions, methods and / or operation sequence diagrams disclosed in this disclosure. Here, processor 202 and memory 204 may be part of a communication modem / circuit / chip designed to embody wireless LAN technology (e.g., IEEE 802.11 series). Transceiver 206 may be coupled with processor 202 and may transmit and / or receive radio signals via one or more antennas 208. Transceiver 206 may include a transmitter and / or receiver. Transceiver 206 may be used synonymously with RF unit. In this disclosure, device may also mean communication modem / circuit / chip.

[0049] The hardware elements of devices 100,200 will be described in more detail below. However, one or more protocol layers may be embodied by one or more processors 102,202. For example, one or more processors 102,202 can embodied one or more layers (e.g., layers with the same functionality, such as PHY and MAC). One or more processors 102,202 can generate one or more PDUs (Protocol Data Units) and / or one or more SDUs (Service Data Units) by means of the descriptions, functions, procedures, proposals, methods and / or operation sequence diagrams in this disclosure. One or more processors 102,202 can generate messages, control information, data, or information by means of the descriptions, functions, procedures, proposals, methods and / or operation sequence diagrams in this disclosure. One or more processors 102,202 can generate signals (e.g., baseband signals) containing PDUs, SDUs, messages, control information, data, or information by the functions, procedures, proposals and / or methods of this disclosure and provide them to one or more transceivers 106,206. One or more processors 102,202 can receive signals (e.g., baseband signals) from one or more transceivers 106,206 and obtain PDUs, SDUs, messages, control information, data, or information by the descriptions, functions, procedures, proposals, methods and / or operation sequence diagrams of this disclosure.

[0050] One or more processors 102,202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. One or more processors 102,202 may be embodied by hardware, firmware, software, or a combination thereof. For example, one or more ASICs (Application Specific Integrated Circuits), one or more DSPs (Digital Signal Processors), one or more DSPDs (Digital Signal Processing Devices), one or more PLDs (Programmable Logic Devices), or one or more FPGAs (Field Programmable Gate Arrays) may be included in one or more processors 102,202. The descriptions, functions, procedures, proposals, methods and / or operation sequence diagrams disclosed in this disclosure may be embodied using firmware or software, and the firmware or software may be embodied to include modules, procedures, functions, etc. Firmware or software configured to perform the descriptions, functions, procedures, suggestions, methods and / or sequence diagrams disclosed in this disclosure may be contained in one or more processors 102,202 or stored in one or more memories 104,204 and driven by one or more processors 102,202. The descriptions, functions, procedures, suggestions, methods and / or sequence diagrams disclosed in this disclosure may be embodied by firmware or software in the form of code, instructions and / or sets of instructions.

[0051] One or more memories 104,204 may be connected to one or more processors 102,202 and can store various forms of data, signals, messages, information, programs, code, instructions and / or commands. One or more memories 104,204 may consist of ROM, RAM, EPROM, flash memory, hard drives, registers, cache memory, computer-readable storage media and / or combinations thereof. One or more memories 104,204 may be located inside and / or outside of one or more processors 102,202. Furthermore, one or more memories 104,204 may be connected to one or more processors 102,202 by various technologies such as wired or wireless connections.

[0052] One or more transceivers 106,206 can transmit user data, control information, radio signals / channels, etc., as referred to in the methods and / or operation sequence diagrams of this disclosure, to one or more other devices. One or more transceivers 106,206 can receive user data, control information, radio signals / channels, etc., as referred to in the descriptions, functions, procedures, proposals, methods and / or operation sequence diagrams disclosed in this disclosure, from one or more other devices. For example, one or more transceivers 106,206 may be coupled with one or more processors 102,202 to transmit and receive radio signals. For example, one or more processors 102,202 can control one or more transceivers 106,206 to transmit user data, control information, or radio signals to one or more other devices. Also, one or more processors 102,202 can control one or more transceivers 106,206 to receive user data, control information, or radio signals from one or more other devices. Furthermore, one or more transceivers 106,206 may be connected to one or more antennas 108,208, and one or more transceivers 106,206 may be configured to transmit and receive user data, control information, radio signals / channels, etc., as referred to in the descriptions, functions, procedures, proposals, methods and / or operation sequence diagrams disclosed in this disclosure, via one or more antennas 108,208. In this disclosure, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106,206 may convert the received user data, control information, radio signals / channels, etc., from RF band signals to baseband signals for processing using one or more processors 102,202. One or more transceivers 106,206 may convert the user data, control information, radio signals / channels, etc., processed by one or more processors 102,202, from baseband signals to RF band signals. To this end, one or more transceivers 106,206 may include (analog) oscillators and / or filters.

[0053] For example, either STA100 or STA200 can perform the intended operation of an AP, and the other STA100 or STA200 can perform the intended operation of a non-AP STA. For example, the transceivers 106 and 206 in Figure 1 can perform the transmission and reception of signals (e.g., packets or PPDUs (Physical Layer Protocol Data Units) conforming to IEEE 802.11a / b / g / n / ac / ax / be, etc.). Furthermore, in this disclosure, the operation of various STAs generating transmission and reception signals or performing data processing and calculations in advance for transmission and reception signals may be performed by the processors 102 and 202 in Figure 1. For example, an example of an operation that generates transmit / receive signals or performs data processing or calculations in advance for transmit / receive signals may include: 1) an operation to determine / acquire / construct / calculate / decode / encode bit information of fields contained within the PPDU (SIG (signal), STF (short training field), LTF (long training field), Data, etc.); 2) an operation to determine / construct / acquire time resources and frequency resources (e.g., subcarrier resources) used for fields contained within the PPDU (SIG, STF, LTF, Data, etc.); 3) an operation to determine / construct / acquire specific sequences (e.g., pilot sequence, STF / LTF sequence, extra sequence applied to SIG) used for fields contained within the PPDU (SIG, STF, LTF, Data, etc.); 4) power control operations and / or power saving operations applied to the STA; and 5) operations related to determining / acquiring / constructing / calculating / decoding / encoding the ACK signal. Furthermore, in the following example, various pieces of information used by various STAs for determining / acquiring / composing / calculating / decoding / encoding the transmit / receive signals (e.g., information about fields / subfields / control fields / parameters / power, etc.) may be stored in memories 104,204 in Figure 1.

[0054] In the following, downlink (DL) refers to the link for communication from AP STA to non-AP STA, and downlink PPDU / packets / signals, etc., may be transmitted and received through the downlink. In downlink communication, the transmitter may be part of AP STA, and the receiver may be part of non-AP STA. Uplink (UL) refers to the link for communication from non-AP STA to AP STA, and uplink PPDU / packets / signals, etc., may be transmitted and received through the uplink. In uplink communication, the transmitter may be part of non-AP STA, and the receiver may be part of AP STA.

[0055] Figure 2 shows an exemplary structure of a wireless LAN system to which this disclosure can be applied.

[0056] The structure of a wireless LAN system may consist of multiple components. A wireless LAN may be provided that supports transparent STA mobility to higher layers through the interaction of multiple components. A BSS (Basic Service Set) corresponds to the basic structural block of a wireless LAN. Figure 2 illustrates the existence of two BSSs (BSS1 and BSS2), with each BSS containing two STAs as members (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). In Figure 2, the ellipses representing the BSSs may be understood as representing the coverage area where the STAs included in that BSS maintain communication. This area can be called a BSA (Basic Service Area). When an STA moves outside a BSA, it can no longer communicate directly with other STAs within that BSA.

[0057] Ignoring the DS shown in Figure 2, the most basic type of BSS in a wireless LAN is the Independent BSS (IBSS). For example, an IBSS can have a minimal form consisting of only two STAs. For instance, assuming other components are omitted, BSS1 consisting only of STA1 and STA2, or BSS2 consisting only of STA3 and STA4, can each be considered a typical example of an IBSS. Such a configuration is possible when STAs can communicate directly without APs. Furthermore, this type of wireless LAN is not pre-planned and configured, but can be configured when the LAN requires it, and can be called an ad-hoc network. Since an IBSS does not include APs, there is no centralized management entity. That is, in an IBSS, STAs are managed in a distributed manner. In an IBSS, all STAs may be mobile STAs, and connection to a distributed system (DS) is not permitted, forming a self-contained network.

[0058] STA membership in the BSS can change dynamically due to actions such as STAs being added or removed, or STAs entering or leaving the BSS area. To become a member of the BSS, an STA can join the BSS using a synchronization process. To access all services of the BSS-based structure, an STA must be associated with the BSS. Such associations may be configured dynamically and may include the use of Distribution System Services (DSS).

[0059] In a wireless LAN, the direct distance between STAs may be limited by the PHY performance. While this distance limit may be sufficient in some cases, there may be situations requiring communication between STAs over longer distances. Distributed systems (DS) may be configured to support extended coverage.

[0060] DS refers to a structure in which BSSs are interconnected. Specifically, as shown in Figure 2, BSSs may exist as components of an extended form of a network composed of multiple BSSs. DS is a logical concept and may be identified by the characteristics of the Distributed System Medium (DSM). In this regard, Wireless Medium (WM) and DSM may be logically distinct. Each logical medium is used for a different purpose and by different components. These mediums are neither limited to being the same nor limited to being different. The flexibility of wireless LAN structures (DS structures or other network structures) can be explained by the fact that multiple mediums are logically distinct from one another. That is, wireless LAN structures can be embodied in various ways, and each embodied example may be identified independently by its physical characteristics.

[0061] DS can support mobile devices by providing seamless integration of multiple BSSs and offering the necessary logical services for handling destination addresses. DS may also include a portal component that acts as a bridge for connecting wireless LANs with other networks (e.g., IEEE 802.X).

[0062] An AP (Application Programming Object) is an entity that enables a coupled non-AP STA (Systematization System) to access the DS (Data Storage System) via the WM (Web Module) and also possesses the functionality of an STA. Data can be moved between the BSS (Base System Storage) and the DS via the AP. For example, STA2 and STA3, shown in Figure 2, possess the functionality of an STA while also providing the ability for coupled non-AP STAs (STA1 and STA4) to access the DS. Furthermore, since all APs are essentially STAs, all APs are addressable entities. The address used by the AP for communication on the WM and the address used by the AP for communication on the DSM (Data Storage System) 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.

[0063] Data transmitted from one of the STAs connected to an AP to the AP's STA address is always received on an uncontrolled port and may be processed by an IEEE 802.1X port access entity. Alternatively, once a controlled port is authenticated, the transmitted data (or frame) may be forwarded to a DS.

[0064] An Extended Service Set (ESS) may be added to the aforementioned DS structure to provide even broader coverage.

[0065] An ESS (Service Set Network) refers to a network of arbitrary size and complexity composed of DSs (Distributed Service Sets) and BSSs (Blockchain Service Sets). An ESS can be a collection of BSSs connected to a single DS. However, an ESS cannot contain a DS. A key feature of an ESS network is that it appears as an IBSS (Internet Link Control Service Set) at the LLC (Logical Link Control) layer. STAs (Stage Attacks) within an ESS can communicate with each other, and mobile STAs can move transparently to the LLC from one BSS to another (within the same ESS). APs (Access Points) within an ESS may have the same SSID (Service Set Identification). An SSID is distinct from a BSSID, which is the identifier for a BSS.

[0066] In wireless LAN systems, no assumptions are made regarding the relative physical location of BSSs, and any of the following forms are possible: BSSs may partially overlap, which is a commonly used form to provide continuous coverage. BSSs do not have to be physically connected, and logically there is no limit to the distance between BSSs. BSSs may also be located in the same physical location, which may be used to provide redundancy. One (or more) IBSS or ESS networks may physically exist in the same space as one (or more) ESS networks. This may include ESS network configurations when an ad hoc network operates in the location where an ESS network exists, when physically overlapping wireless networks are configured by different organizations, or when two or more different access and security policies are required at the same location.

[0067] Figure 3 is a diagram illustrating the link setup process to which this disclosure can be applied.

[0068] For an STA to set up a link to a network and send and receive data, it must first discover the network, perform authentication, establish an association, and carry out security authentication procedures. The link setup process can be called the session initiation process or session setup process. Alternatively, the discovery, authentication, association, and security setting processes of the link setup process can be collectively referred to as the association process.

[0069] In step S310, the STA can perform a network discovery operation. The network discovery operation may include the STA's scanning operation. That is, in order for the STA to access a network, it must find a network that it can join. Before joining a wireless network, the STA must identify a compatible network, and the process of identifying networks in a specific area is called scanning.

[0070] There are two scanning methods: active scanning and passive scanning. Figure 3 illustrates a network discovery operation that includes the active scanning process. In active scanning, the STA performing the scanning sends a probe request frame to search for nearby APs while moving between channels, and waits for a response. The responder sends a probe response frame to the STA that sent the probe request frame. Here, the responder may be the STA that last sent a beacon frame in the BSS of the channel being scanned. In BSS, APs send beacon frames, so APs become the responders, while in IBSS, STAs within IBSS alternately send beacon frames, so the responders are not constant. For example, an STA that sends a probe request frame on channel 1 and receives a probe response frame on channel 1 can save the BSS-related information contained in the received probe response frame and move to the next channel (e.g., channel 2) to perform scanning in the same way (i.e., send and receive probe requests / responses on channel 2).

[0071] Although not shown in Figure 3, scanning may also be performed using a passive scanning method. In passive scanning, the STA performing the scanning waits for beacon frames while switching channels. A beacon frame is one of the management frames defined in IEEE 802.11, and is transmitted periodically to announce the presence of a wireless network, allowing the scanning STA to find and join the wireless network. In BSS, APs are responsible for periodically transmitting beacon frames, while in IBSS, STAs within IBSS transmit beacon frames alternately. When the scanning STA receives a beacon frame, it stores the BSS information contained in the beacon frame and records the beacon frame information on each channel while moving to other channels. An STA that has received a beacon frame can store the BSS-related information contained in the received beacon frame and move to the next channel to perform scanning on the next channel in the same way. Comparing active scanning and passive scanning, active scanning has the advantage of less delay and power consumption compared to passive scanning.

[0072] After the STA discovers the network, an authentication process may be performed in step S320. This authentication process can be called the first authentication process to clearly distinguish it from the security setup operation in step S340, which will be described later.

[0073] The authentication process involves the STA sending an authentication request frame to the AP, and the AP responding by sending an authentication response frame to the STA. The authentication frame used in the authentication request / response corresponds to the management frame.

[0074] The authentication frame may include information such as the authentication algorithm number, authentication transaction sequence number, status code, challenge text, Robust Security Network (RSN), and Finite Cyclic Group. This is just an example of some of the information that may be included in the authentication request / response frame, and may be replaced by other information or may contain additional information.

[0075] The STA can send an authentication request frame to the AP. Based on the information contained in the received authentication request frame, the AP can decide whether or not to allow authentication to the STA. The AP can provide the STA with the result of the authentication process using an authentication response frame.

[0076] After the STA has been successfully authenticated, the association process may take place in step S330. The association process includes the STA sending an association request frame to the AP, and the AP sending an association response frame to the STA in response.

[0077] For example, an association request frame may include information about various capacities, such as the beacon listening interval, SSID (service set identifier), supported rates, supported channels, RSN, mobility domain, supported operating classes, TIM broadcast request (Traffic Indication Map Broadcast request), and interworking service capacity. For example, an association response frame may include information about various capacities, such as the status code, AID (Association ID), supported rates, EDCA (Enhanced Distributed Channel Access) parameter set, RCPI (Received Channel Power Indicator), RSNI (Received Signal to Noise Indicator), mobility domain, timeout interval (e.g., association comeback time), overlapping BSS scan parameters, TIM broadcast response, and QoS (Quality of Service) map. This is an example of some of the information that may be included in a join request / response frame, and may be replaced by other information or may include additional information.

[0078] After the STA is successfully connected to the network, the security setup process may be performed in step S340. The security setup process in step S340 can also be described as an authentication process using RSNA (Robust Security Network Association) request / response, and the authentication process in step S320 can be called the first authentication process, while the security setup process in step S340 can simply be called the authentication process.

[0079] The security setup process in stage S340 may include, for example, a process of private key setup using a four-way handshake with an EAPOL (Extensible Authentication Protocol over LAN) frame. Furthermore, the security setup process may be performed using a security method not defined in the IEEE 802.11 standard.

[0080] Figure 4 is a diagram illustrating the backoff process to which this disclosure can be applied.

[0081] In wireless LAN systems, the basic access mechanism of MAC (Medium Access Control) is the CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) mechanism. The CSMA / CA mechanism is also called the Distributed Coordination Function (DCF) of IEEE 802.11 MAC, and basically employs a "listen before talk" access mechanism. With this type of access mechanism, an AP and / or STA can perform a Clear Channel Assessment (CCA) to sense the radio channel or medium within a predetermined time interval (e.g., DIFS Inter-Frame Space) before initiating transmission. If the sensing determines that the medium is idle, the AP and / or STA will begin transmitting a frame through that medium. On the other hand, if the medium is perceived as occupied or busy, the AP and / or STA will not begin transmitting itself, but will wait for a delay period (e.g., a random backoff period) for medium access before attempting to transmit a frame. By applying a random backoff period, multiple STAs are expected to attempt to transmit frames after waiting for different periods of time from each other, thus minimizing collisions.

[0082] Furthermore, the IEEE 802.11 MAC protocol provides HCF (Hybrid Coordination Function). HCF is based on the aforementioned DCF and PCF (Point Coordination Function). PCF is a polling-based synchronous access method that periodically polls so that all receiving APs and / or STAs can receive data frames. HCF also has EDCA (Enhanced Distributed Channel Access) and HCCA (HCF Controlled Channel Access). EDCA is a competition-based access method for a provider to provide data frames to multiple users, while HCCA uses a non-competition-based channel access method with a polling mechanism. In addition, HCF includes a media access mechanism to improve the QoS (Quality of Service) of wireless LANs and can transmit QoS data during both the Contention Period (CP) and the Contention Free Period (CFP).

[0083] Refer to Figure 4 to explain the operation based on the random backoff period. When a medium that was occupied / busy changes to idle, multiple STAs can attempt to transmit data (or frames). As a way to minimize collisions, each STA can select a random backoff count and wait for the corresponding slot time before attempting to transmit. The random backoff count has a pseudo-random integer value and may be determined to any one of the values ​​in the range of 0 to CW, where CW is the Contention Window parameter value. The CW parameter is initially given as CWmin, but can take twice that value in case of transmission failure (e.g., if an ACK for a transmitted frame is not received). When the CW parameter value becomes CWmax, the STA can attempt to transmit data while maintaining the CWmax value until successful data transmission occurs, at which point it is reset to the CWmin value. The CW, CWmin, and CWmax values ​​are 2 n It is preferable to set it to -1 (n=0,1,2,...).

[0084] Once the random backoff process begins, the STA continues to monitor the media while counting down the backoff slots according to the determined backoff count value. When the media is monitored as occupied, the countdown stops and it waits; when the media becomes idle, the remaining countdown resumes.

[0085] In the example in Figure 4, when a packet to be transmitted reaches the MAC of STA3, STA3 can immediately transmit the frame after confirming that the medium is idle for DIFS only. The remaining STAs monitor the occupied / busy state of the medium and wait. Meanwhile, data to be transmitted may also be generated in STA1, STA2, and STA5. When each STA monitors the medium as idle, after waiting for DIFS only, it can count down the backoff slot using a random backoff count value of its choice. Assume that STA2 selects the minimum backoff count value and STA1 selects the maximum backoff count value. That is, the example illustrates a case where the remaining backoff time for STA5 is shorter than the remaining backoff time for STA1 when STA2 finishes its backoff count and begins transmitting a frame. STA1 and STA5 pause their countdown and wait for a while while STA2 occupies the medium. When STA2's occupation ends and the medium becomes idle again, STA1 and STA5 wait for DIFS only before resuming the paused backoff count. In other words, frame transmission can begin after counting down the remaining backoff slots equal to the remaining backoff time. Since STA5's remaining backoff time was shorter than STA1's, STA5 begins frame transmission. Data to transmit may also occur in STA4 while STA2 is occupying the medium. From STA4's perspective, when the medium becomes idle, it can wait for DIFS, then count down using a random backoff count value of its choosing, and begin frame transmission. The example in Figure 4 shows a case where STA5's remaining backoff time coincidentally matches STA4's random backoff count value, in which case a collision may occur between STA4 and STA5. If a collision occurs, neither STA4 nor STA5 will receive an ACK, and data transmission will fail. In this case, STA4 and STA5 can double their CW value, select a random backoff count value, and then perform the countdown.STA1 waits while the medium is occupied by transmissions from STA4 and STA5. When the medium becomes idle, STA1 waits only for DIFS, and can begin transmitting frames after the remaining backoff time has elapsed.

[0086] As illustrated in Figure 4, data frames are used to transmit data forwarded to higher layers and may be transmitted after a backoff that occurs after DIFS has elapsed, from the time the medium becomes idle. Furthermore, management frames are used to exchange management information that is not forwarded to higher layers and are transmitted after a backoff that occurs after an IFS such as DIFS or PIFS (Point Coordination Function IFS) has elapsed. Subtypes of management frames include beacons, association request / response, re-association request / response, probe request / response, and authentication request / response. Control frames are used to control access to the medium. Control frame subtypes include RTS (Request-To-Send), CTS (Clear-To-Send), ACK (Acknowledgment), PS-Poll (Power Save-Poll), Block ACK (BlockAck), Block ACK Request (BlockACKReq), and NDP. Announcement Examples include (null data packet announcement) and Trigger. A control frame is sent after a backoff that occurs after DIFS if it is not a response frame to a previous frame, and without a backoff after SIFS (short IFS) if it is a response frame to a previous frame. The frame type and subtype may be identified by the type field and subtype field in the frame control (FC) field.

[0087] A Quality of Service (QoS) STA can transmit a frame after an arbitration IFS (AIFS) for the access category (AC) to which the frame belongs, i.e., after a backoff that occurs after AIFS[i] (where i is a value determined by the AC). Frames for which AIFS[i] is available can be data frames, management frames, or control frames that are not response frames.

[0088] Figure 5 is a diagram illustrating the CSMA / CA baseframe transmission operation to which this disclosure can be applied.

[0089] As mentioned earlier, the CSMA / CA mechanism includes not only physical carrier sensing, where the STA directly senses the medium, but also virtual carrier sensing. Virtual carrier sensing is intended to compensate for problems that can occur in medium access, such as the hidden node problem. For virtual carrier sensing, the STA's MAC can utilize the Network Allocation Vector (NAV). The NAV is a value that indicates to other STAs the time remaining until the medium becomes available, used by an STA that is currently using or authorized to use the medium. Therefore, the value set as the NAV corresponds to the period during which the STA sending the frame is scheduled to use the medium, and STAs receiving the NAV value are prohibited from accessing the medium during that period. For example, the NAV may be set based on the value of the "duration" field in the frame's MAC header.

[0090] In the example shown in Figure 5, we assume that STA1 is attempting to transmit data to STA2, and STA3 is in a position where it can overhear some or all of the frames transmitted and received between STA1 and STA2.

[0091] In CSMA / CA baseframe transmission operation, a mechanism utilizing RTS / CTS frames may be applied to reduce the possibility of collisions between transmissions from multiple STAs. In the example in Figure 5, while STA1 is transmitting, carrier sensing by STA3 may determine that the medium is idle. That is, STA1 may be a hidden node for STA3. Alternatively, in the example in Figure 5, while STA2 is transmitting, carrier sensing by STA3 may determine that the medium is idle. That is, STA2 may be a hidden node for STA3. By exchanging RTS / CTS frames before data transmission and reception between STA1 and STA2, it is possible to prevent STAs outside the transmission range of either STA1 or STA2, or STAs outside the carrier sensing range for transmissions from STA1 or STA3, from attempting to occupy the channel during data transmission and reception between STA1 and STA2.

[0092] Specifically, STA1 can determine whether a channel is in use or not using carrier sensing. In terms of physical carrier sensing, STA1 can determine the channel's occupied or idle state based on the energy magnitude or signal correlation detected from the channel. In terms of virtual carrier sensing, STA1 can determine the channel's occupied state using a network allocation vector (NAV) timer.

[0093] STA1 can send an RTS frame to STA2 after backoff if the channel is idle during DIFS. STA2, upon receiving an RTS frame, can send a CTS frame, which is a response to the RTS frame, to STA1 after SIFS.

[0094] If STA3 cannot overhear CTS frames from STA2 but can overhear RTS frames from STA1, STA3 can use the duration information contained in the RTS frames to set the NAV timer for subsequent consecutive frame transmission periods (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame). Alternatively, if STA3 cannot overhear RTS frames from STA1 but can overhear CTS frames from STA2, STA3 can use the duration information contained in the CTS frames to set the NAV timer for subsequent consecutive frame transmission periods (e.g., SIFS + data frame + SIFS + ACK frame). In other words, STA3 can set NAV based on overhearing one or more RTS or CTS frames from at least one of STA1 or STA2. If STA3 receives a new frame before the NAV timer expires, it can update the NAV timer using the duration information contained in the new frame. STA3 will not attempt to access the channel until the NAV timer expires.

[0095] When STA1 receives a CTS frame from STA2, it can send a data frame to STA2 after SIFS from the time it has finished receiving the CTS frame. If STA2 successfully receives the data frame, it can send an ACK frame, which is a response to the data frame, to STA1 after SIFS. When the NAV timer expires, STA3 can use carrier sensing to determine whether or not the channel is in use. If STA3 determines that the channel is not being used by another terminal between the expiration of the NAV timer and DIFS, it can attempt to access the channel after the random backoff conflict window (CW) has passed.

[0096] Figure 6 is a diagram illustrating an example of a frame structure used in a wireless LAN system to which this disclosure can be applied.

[0097] The PHY layer can prepare the MPDU (MAC PDU) to be transmitted based on instructions or primitives (meaning a set of instructions or parameters) from the MAC layer. For example, when the PHY layer receives an instruction from the MAC layer requesting it to start transmitting, it switches to transmit mode and can assemble the information provided by the MAC layer (e.g., data) into a frame and transmit it. Also, when the PHY layer detects a valid preamble in the frame it is receiving, it monitors the preamble header and sends an instruction to the MAC layer to signal that the PHY layer has started receiving.

[0098] Thus, information transmission and reception in wireless LAN systems are performed in the form of frames, and for this purpose, the Physical Layer Protocol Data Unit (PPDU) frame format is defined.

[0099] A basic PPDU frame may include an STF (Short Training Field), an LTF (Long Training Field), a SIG (SIGNAL) field, and a Data field. The most basic (e.g., non-HT (High Throughput)) PPDU frame format may consist only of an L-STF (Legacy-STF), an L-LTF (Legacy-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, VHT (Very High Throughput) PPDU, etc.), additional (or other types of) STF, LTF, and SIG fields may be included between the SIG field and the Data field (see Figure 7 below for further details).

[0100] STF is a signal used for signal detection, AGC (Automatic Gain Control), diversity selection, and precise time synchronization, while LTF is a signal used for channel estimation and frequency error estimation. In essence, STF and LTF are signals for synchronizing the OFDM physical layer and for channel estimation.

[0101] The SIG field may include fields such as the RATE field and the LENGTH field. The RATE field may contain information about the modulation and coding rate of the data. The LENGTH field may contain information about the length of the data. Furthermore, the SIG field may include a parity bit, a SIG TAIL bit, and so on.

[0102] The data field may include a SERVICE field, a PSDU (Physical Layer Service Data Unit), and PPDU TAIL bits, and may also include padding bits if necessary. Some bits of the SERVICE field may be used for synchronizing the descramble at the receiving end. The PSDU corresponds to the MAC PDU defined in the MAC layer and may contain data generated / used in higher layers. The PPDU TAIL bits may be used to return the encoder to a 0 state. Padding bits may be used to adjust the length of the data field to a predetermined unit.

[0103] MAC PDUs are defined by various MAC frame formats, and a basic MAC frame consists of a MAC header, frame body, and FCS (Frame Check Sequence). MAC frames are composed of MAC PDUs and may be transmitted / received by PSDUs, which are the data portion of the PPDU frame format.

[0104] The MAC header includes fields such as Frame Control, Duration / ID, and Address. The Frame Control field may contain control information necessary for transmitting / receiving frames. The Duration / ID field may be set to the time required to transmit the frame. For specific details on the Sequence Control, QoS Control, and HT Control subfields of the MAC header, refer to the IEEE 802.11 standard document.

[0105] The Null Data Packet (NDP) frame format refers to a frame format that does not include data packets. That is, an NDP frame is a frame format that includes the PLCP (Physical Layer Convergence Procedure) header portion (i.e., the STF, LTF, and SIG fields) of a typical PPDU frame format, but omits the remaining portion (i.e., the data fields). NDP frames can also be referred to as short frame formats.

[0106] Figure 7 shows an example of a PPDU as defined in the IEEE 802.11 standard to which this disclosure applies.

[0107] Standards such as IEEE 802.11a / g / n / ac / ax use various forms of PPDU. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and Data fields. The basic PPDU format can also be referred to as the non-HT PPDU format.

[0108] The HT PPDU format (IEEE 802.11n) further includes the HT-SIG, HT-STF, and HT-LFT(s) fields in addition to the basic PPDU format. The HT PPDU format shown in Figure 7 can be called the HT-mixed format. The HT-greenfield format PPDU may be further defined, which does not include L-STF, L-LTF, and L-SIG, and consists of the HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTF, and Data fields (not shown).

[0109] An example of the VHT PPDU format (IEEE 802.11ac) is that it further includes the VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in addition to the basic PPDU format.

[0110] An example of the HE PPDU format (IEEE 802.11ax) further includes the RL-SIG (Repeated L-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), and PE (Packet Extension) fields in addition to the basic PPDU format. Depending on the specific example of the HE PPDU format, some fields may be omitted or their lengths may change. For example, the HE-SIG-B field is included in the HE PPDU format for multiple users (MU), while it is not included in the HE PPDU format for single users (SU). Also, the HE trigger-based (TB) PPDU format does not include HE-SIG-B, and the length of the HE-STF field may be changed to 8us. The HE ER (Extended Range) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may be changed to 16us.

[0111] Figures 8 to 10 illustrate examples of resource units in a wireless LAN system to which this disclosure can be applied.

[0112] Referring to Figures 8 to 10, a resource unit (RU) defined in a wireless LAN system will be explained. An RU may contain multiple subcarriers (or tones). An RU may be used when transmitting a signal to multiple STAs based on the OFDMA method. An RU may also be defined when transmitting a signal to a single STA. An RU may be used for the STF, LTF, data field, etc., of a PPDU.

[0113] As shown in Figures 8 to 10, RUs corresponding to different numbers of tones (i.e., subcarriers) can be used to constitute some fields of a 20MHz, 40MHz, or 80MHz X-PPDU (where 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.

[0114] Figure 8 shows an example of resource unit (RU) configuration used in the 20 MHz bandwidth.

[0115] As shown at the top of Figure 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 20MHz band, and five tones may be used as a guard band in the rightmost band of the 20MHz band. In addition, seven DC tones may be inserted in 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. Furthermore, 26, 52, or 106 units may be allocated to the other bands. Each unit may be allocated for the STA or the user.

[0116] The RU configuration in Figure 8 can be used not only for situations involving multiple users (MU) but also for situations involving a single user (SU), in which case it is possible to use one 242 unit as shown at the bottom of Figure 8. In this case, three DC tones may be inserted.

[0117] In the example shown in Figure 8, various sizes of RUs are illustrated, such as 26-RU, 52-RU, 106-RU, and 242-RU, but the specific sizes 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 this disclosure and is illustrative. Also, in this disclosure, the number of RUs within a given bandwidth (e.g., 20, 40, 80, 160, 320 MHz, ...) may differ depending on the size of the RU. The same applies to the example in Figure 8 as to the example in Figure 9 and / or Figure 10 described below, in which the size and / or number of RUs may be changed.

[0118] Figure 9 shows an example arrangement of resource units (RUs) used in the 40 MHz bandwidth.

[0119] Just as various sizes of RU were used in the example in Figure 8, 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, etc., may be used in the example in Figure 9. In addition, five DC tones may be inserted at the center frequency, twelve tones may be used as a guard band in the leftmost band of the 40MHz bandwidth, and eleven tones may be used as a guard band in the rightmost band of the 40MHz bandwidth.

[0120] Furthermore, as shown in the figure, 484-RU may be used when it is used for a single user.

[0121] Figure 10 shows an example arrangement of resource units (RUs) used in the 80 MHz bandwidth.

[0122] Just as various sizes of RUs were used in the examples in Figures 8 and 9, 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, 996-RU, etc., may be used in the example in Figure 10. Furthermore, in the 80MHz PPDU, the RU arrangement of the HE PPDU and EHT PPDU may differ from each other, and the example in Figure 10 shows an example of the RU arrangement for the 80MHz EHT PPDU. In the example in Figure 10, the leftmost band of the 80MHz bandwidth uses 12 tones as a guard band, and the rightmost band of the 80MHz bandwidth uses 11 tones as a guard band, which is the same for both the HE PPDU and the EHT PPDU. Unlike the HE PPDU, where seven DC tones are inserted into the DC band and there is one 26-RU on each side of the DC band corresponding to 13 tones, the EHT PPDU has 23 DC tones inserted into the DC band and one 26-RU on both the left and right sides of the DC band. Unlike the HE PPDU, where there is one null subcarrier between 242-RUs that are not in the center band, the EHT PPDU has five null subcarriers. In the HE PPDU, one 484-RU does not contain null subcarriers, but in the EHT PPDU, one 484-RU contains five null subcarriers.

[0123] Furthermore, as shown in the same figure, the 996-RU may be used when used for a single user, and in this case, the insertion of five DC tones is common to both the HE PPDU and the EHT PPDU.

[0124] An EHT PPDU of 160MHz or higher may be configured with multiple 80MHz subblocks as shown in Figure 10. The RU configuration for each 80MHz subblock may be the same as the RU configuration for the 80MHz EHT PPDU in Figure 10. When the 80MHz subblock of a 160MHz or 320MHz EHT PPDU is not punctured and the entire 80MHz subblock is used as part of an RU or MRU (Multiple RU), the 80MHz subblock may use RU 996-996 as shown in Figure 10.

[0125] Here, an MRU corresponds to a group of subcarriers (or tones) composed of multiple RUs, and the multiple RUs constituting an MRU may be of the same size or of different sizes. For example, a single MRU may be defined as 52+26-tone, 106+26-tone, 484+242-tone, 996+484-tone, 996+484+242-tone, 2×996+484-tone, 3×996-tone, or 3×996+484-tone. Here, the multiple RUs constituting a single MRU may correspond to small-sized RUs (e.g., 26, 52, 106) or large-sized RUs (e.g., 242, 484, 996, etc.). That is, a single MRU containing both small-sized and large-sized RUs may not be set / defined. Also, the multiple RUs constituting a single MRU may or may not be consecutive in the frequency domain.

[0126] If the 80MHz subblock contains RUs smaller than 996 tones, or if a portion of the 80MHz subblock is punctured, the 80MHz subblock may use an RU arrangement excluding 996-tone RUs.

[0127] The RUs of this disclosure may be used in uplink (UL) and / or downlink (DL) communication. For example, in the case of trigger-based UL-MU communication, an STA (e.g., AP) transmitting 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. The first STA can then transmit a first trigger-based (TB) PPDU based on the first RU, and the second STA can 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.

[0128] For example, when a DL MU PPDU is configured, the STA (e.g., AP) sending the DL MU PPDU can assign a first RU (e.g., 26 / 52 / 106 / 242-RU) to the first STA and a second RU (e.g., 26 / 52 / 106 / 242-RU) to the second STA. That is, the sending STA (e.g., AP) can use the first RU to send the HE-STF, HE-LTF, and Data fields for the first STA within a single MU PPDU, and use the second RU to send the HE-STF, HE-LTF, and Data fields for the second STA.

[0129] Information regarding the RU's placement may be signaled via HE-SIG-B in HE PPDU format.

[0130] Figure 11 shows an exemplary structure of the HE-SIG-B field.

[0131] As shown in the figure, the HE-SIG-B field may include a common field and a user-specific field. When HE-SIG-B compression is applied (for example, in full-bandwidth MU-MIMO transmission), the common field may not be included in HE-SIG-B, and the HE-SIG-B content channel may include only the user-specific field. When HE-SIG-B compression is not applied, the common field may be included in HE-SIG-B.

[0132] Common fields may include information related to RU allocation (e.g., RU assignment, RUs allocated for MU-MIMO, number of MU-MIMO users (STAs), etc.).

[0133] The common field may contain N*8 RU allocation subfields, where N is the number of subfields, and may have values ​​such as N=1 for 20 or 40MHz MU PPDU, N=2 for 80MHz MU PPDU, N=4 for 160MHz or 80+80MHz MU PPDU, and so on. One 8-bit RU allocation subfield can indicate the size (26, 52, 106, etc.) and frequency position (or RU index) of RUs included in the 20MHz band.

[0134] For example, if the value of the 8-bit RU allocation subfield is 00000000, nine 26-RUs are arranged sequentially from left to right in the example shown in Figure 8. If the value is 00000001, seven 26-RUs and one 52-RU are arranged sequentially from left to right. If the value is 00000010, five 26-RUs, one 52-RU, and two 26-RUs are arranged sequentially from left to right.

[0135] As an additional example, if the value of the 8-bit RU allocation subfield is 01000y2y1y0, then one 106-RU and five 26-RUs are arranged sequentially from left to right in the example in Figure 8. In this case, multiple users / STAs may be assigned to the 106-RU using the MU-MIMO method. Specifically, up to eight users / STAs may be assigned to the 106-RU, and the number of users / STAs assigned to the 106-RU is determined based on the 3-bit information (i.e., y2y1y0). For example, if the 3-bit information (y2y1y0) corresponds to a decimal value N, then the number of users / STAs assigned to the 106-RU may be N+1.

[0136] 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-tones, ...), multiple users / STAs may be assigned to a single RU, and the MU-MIMO scheme may be applied to such multiple users / STAs.

[0137] The set of user-specific fields contains information about how all users (STAs) of the PPDU decode their payload. 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 in 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, by the symbol count of HE-SIG-B, or by the MU-MIMO user field of HE-SIG-A. User-specific fields may be encoded separately or independently of common fields.

[0138] Figure 12 is a diagram illustrating the MU-MIMO scheme in which multiple users / STAs are assigned to a single RU.

[0139] In the example in Figure 12, we assume 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 be shown that 3 (=N+1) users are assigned to one RU. In this case, one 106-RU and five 26-RUs may be arranged sequentially from the leftmost to the rightmost of a particular 20MHz band / channel. Three users / STAs may be assigned to the 106-RU in a MU-MIMO manner. As a result, a total of 8 users / STAs are assigned to the 20MHz band / channel, and the user-specific field of HE-SIG-B may contain 8 user fields (i.e., 4 user block fields). The 8 user fields may be assigned to RUs as shown in Figure 12.

[0140] User fields may be constructed based on two formats. User fields for MU-MIMO assignments may be constructed in the first format, and user fields for non-MU-MIMO assignments may be constructed in the second format. Referring to an example in Figure 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 and second formats may contain bit information of the same length (e.g., 21 bits).

[0141] The user fields of the first format (i.e., the format for MU-MIMO assignment) may be configured as follows: For example, of the total 21 bits of a single user field, B0 to B10 may contain the user's identification information (e.g., STA-ID, AID, partial AID, etc.), B11 to B14 may contain spatial configuration information such as the number of spatial streams for the user, B15 to B18 may contain MCS (Modulation and coding scheme) information applied to the Data field of the PPDU, B19 may be defined as a reserved field, and B20 may contain coding type information applied to the Data field of the PPDU (e.g., BCC (binary convolutional coding) or LDPC (low-density parity check)).

[0142] The user field of the second format (i.e., the format for non-MU-MIMO assignments) may be configured as follows: For example, of the 21 bits in a single user field, B0 to B10 may contain the user's identification information (e.g., STA-ID, AID, partial AID, etc.), B11 to B13 may contain spatial stream number (NSTS) information applied to the RU, B14 may contain information indicating whether beamforming is possible (or whether a beamforming steering matrix can be applied), B15 to B18 may contain MCS (Modulation and coding scheme) information applied to the Data field of the PPDU, B19 may contain information indicating whether DCM (dual carrier modulation) can be applied, and B20 may contain coding type information applied to the Data field of the PPDU (e.g., BCC or LDPC).

[0143] The terms MCS, MCS information, MCS index, and MCS field used in this disclosure may be represented by specific index values. For example, MCS information may be represented by index 0 to index 11. MCS information may include information about the star modulation type (e.g., BPSK, QPSK, 16-QAM, 64-QAM, 256-QAM, 1024-QAM, etc.) and information about the coding rate (e.g., 1 / 2, 2 / 3, 3 / 4, 5 / 6, etc.). Information about the channel coding type (e.g., BCC or LDPC) may be omitted from the MCS information.

[0144] Figure 13 shows examples of PPDU formats to which this disclosure can be applied.

[0145] The PPDU in Figure 13 may be referred to by various names such as EHT PPDU, Transmit PPDU, Receive PPDU, Type 1 or Type N PPDU. For example, the PPDU or EHT PPDU of this disclosure can be referred to by various names such as Transmit PPDU, Receive PPDU, Type 1 or Type N PPDU. Furthermore, the EHT PPU can be used in EHT systems and / or new wireless LAN systems that improve upon EHT systems.

[0146] The EHT MU PPDU in Figure 13 corresponds to a carry PPDU that carries one or more data (or PSDUs) for one or more users. In other words, the EHT MU PPDU may be used for either SU transmissions or MU transmissions. For example, the EHT MU PPDU may correspond to a PPDU for one or more receiving STAs.

[0147] In Figure 13, the EHT TB PPDU omits the EHT-SIG compared to the EHT MU PPDU. An STA that receives a trigger for UL MU transmission (e.g., a trigger frame or TRS) can perform the UL transmission based on the EHT TB PPDU format.

[0148] In the example of the EHT PPDU format shown in Figure 13, L-STF to EHT-LTF correspond to the preamble or physical preamble and may be generated / transmitted / received / acquired / decoded at the physical layer.

[0149] The subcarrier frequency spacing for L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal SIGNAL), and EHT-SIG fields (collectively referred to as pre-EHT modulated fields) may be set to 312.5 kHz. The subcarrier frequency spacing for EHT-STF, EHT-LTF, Data, and PE fields (collectively referred to as EHT modulated fields) may be set to 78.125 kHz. In other words, the tone / subcarrier index for L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-SIG fields may be displayed in units of 312.5 kHz, while the tone / subcarrier index for EHT-STF, EHT-LTF, Data, and PE fields may be displayed in units of 78.125 kHz.

[0150] The L-LTF and L-STF in Figure 13 may be configured identically to the corresponding fields of the PPDU described in Figures 6 and 7.

[0151] The L-SIG field in Figure 13 consists 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 contain information about the length or time duration of the PPDU. For example, the value of the 12-bit Length field may be determined based on the type of PPDU. For example, for non-HT, HT, VHT, or EHT PPDUs, the value of the Length field may be determined to be a multiple of 3. For example, for HE PPDUs, the value of the Length field may be determined to be a multiple of 3 + 1 or a multiple of 3 + 2.

[0152] For example, a transmitting STA can apply BCC encoding based on half the coding rate to 24 bits of information in the L-SIG field. The transmitting STA can then obtain 48 bits of BCC encoded bits. BPSK modulation may be applied to the 48 bits of encoded bits to generate 48 BPSK symbols. The transmitting STA can map the 48 BPSK symbols to positions excluding the pilot subcarrier (e.g., {subcarrier indices -21, -7, +7, +21}) and the DC subcarrier (e.g., {subcarrier index 0}). Consequently, the 48 BPSK symbols may be mapped to subcarrier indices -26 to -22, -20 to -8, -6 to -1, +1 to +6, +8 to +20, and +22 to +26. The transmitting STA can further map the signal {-1, -1, -1, 1} to subcarrier indices {-28, -27, +27, +28}. The signal may be used for channel estimation in the frequency domain corresponding to {-28, -27, +27, +28}.

[0153] The transmitting STA can generate an RL-SIG that 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 either an HE PPDU or an EHT PPDU.

[0154] A U-SIG (Universal SIG) may be inserted after the RL-SIG in Figure 13. The U-SIG can be named in various ways, such as first SIG field, first SIG, first type SIG, control signal, control signal field, or first (type) control signal.

[0155] A U-SIG may contain N bits of information, including information to identify the type of EHT PPDU. For example, a U-SIG may consist of two symbols (e.g., two consecutive OFDM symbols). Each symbol for the U-SIG (e.g., an OFDM symbol) 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 bits of information. For example, each symbol of the U-SIG may be transmitted and received based on 52 data tones and 4 pilot tones.

[0156] In a U-SIG (or U-SIG field), for example, A-bit information (e.g., 52 uncoded bits) may be transmitted. The first symbol of the U-SIG (e.g., U-SIG-1) may transmit the first X bits of the total A-bit information (e.g., 26 uncoded bits), and the second symbol of the U-SIG (e.g., U-SIG-2) may transmit the remaining Y bits of the total A-bit information (e.g., 26 uncoded bits). For example, a transmitting STA can obtain the 26 uncoded bits contained 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 to be assigned to each U-SIG symbol. A single 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.

[0157] For example, the A-bit information transmitted by the U-SIG (e.g., 52 uncoded bits) may include a CRC field (e.g., a 4-bit field) and a tail field (e.g., a 6-bit field). The CRC field and tail field may be transmitted in a second symbol of the U-SIG. The CRC field may be generated based on 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 the convolution decoder and may be set to 0, for example.

[0158] The A-bit information transmitted by the U-SIG (or U-SIG field) (e.g., 52 uncoded bits) 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 they may be assigned to both the first and second symbols of the U-SIG. For example, the version-independent bits and version-dependent bits may have various names, such as first control bits and second control bits.

[0159] For example, the version-independent bits of the U-SIG may include a 3-bit physical layer version identifier (PHY version identifier). For example, the 3-bit PHY version identifier may contain information about the physical layer version (PHY version) of the transmitted and received PPDUs. For example, the first value of the 3-bit PHY version identifier can indicate that the transmitted and received PPDUs are EHT PPDUs. In other words, a transmitting STA can set the 3-bit PHY version identifier to the first value when transmitting an EHT PPDU. In other words, a receiving STA can determine that the received PPDU is an EHT PPDU based on the PHY version identifier having the first value.

[0160] For example, the version-independent bits of a U-SIG may include a 1-bit UL / DL flag field. The first value of the 1-bit UL / DL flag field is related to UL communication, and the second value of the UL / DL flag field is related to DL communication.

[0161] For example, the version-independent bits of the U-SIG may include information about the length of the TXOP (transmission opportunity) and information about the BSS color ID.

[0162] For example, if EHT PPDUs are categorized 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 version-dependent bits of the U-SIG.

[0163] For example, a U-SIG may include information about: 1) a bandwidth field containing information about bandwidth; 2) a field containing information about the MCS method applied to the EHT-SIG; 3) an indication field containing information about whether or not the DCM method is applied to the EHT-SIG; 4) a field containing information about the number of symbols used for the EHT-SIG; 5) a field containing information about whether or not the EHT-SIG is generated across the entire bandwidth; 6) a field containing information about the type of EHT-LTF / STF; and 7) fields indicating the length of the EHT-LTF and the CP length.

[0164] Preamble puncturing may be applied to the PPDU in Figure 13. Preamble puncturing can mean the transmission of a PPDU in which one or more 20 MHz subchannels within the PPDU bandwidth are not present. Preamble puncturing may be applied to PPDUs transmitted to one or more users. For example, the resolution of preamble puncturing may be 20 MHz for EHT MU PPDUs in OFDMA transmissions with bandwidths greater than 40 MHz and non-OFDMA transmissions with bandwidths of 80 MHz and 160 MHz. That is, in the above case, puncturing of subchannels smaller than 242-tone RU may not be permitted. Also, for EHT MU PPDUs in non-OFDMA transmissions with a bandwidth of 320 MHz, the resolution of preamble puncturing may be 40 MHz. That is, puncturing of subchannels smaller than 484-tone RU in a 320 MHz bandwidth may not be permitted. Furthermore, in EHT MU PPDU, preamble puncturing does not need to be applied to the primary 20MHz channel.

[0165] For example, for an EHT MU PPDU, information regarding preamble puncturing may be included in the U-SIG and / or EHT-SIG. For instance, the first field of the U-SIG may include information regarding the contiguous bandwidth of the PPDU, and the second field of the U-SIG may include information regarding the preamble puncturing applied to the PPDU.

[0166] For example, U-SIGs and EHT-SIGs may include information about preamble puncturing based on the following method: If the bandwidth of the PPDU exceeds 80 MHz, the U-SIGs may be configured individually in 80 MHz units. For example, if the bandwidth of the PPDU is 160 MHz, the PPDU may include a first U-SIG for the first 80 MHz band and a second U-SIG for the 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 preamble puncturing applied to the first 80 MHz band (i.e., information about the preamble puncturing pattern). 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 preamble puncturing applied to the second 80 MHz band (i.e., information about the preamble puncturing pattern). An EHT-SIG following the first U-SIG may include information about preamble puncturing applied to the second 80 MHz band (i.e., information about the preamble puncturing pattern), and an EHT-SIG following the second U-SIG may include information about preamble puncturing applied to the first 80 MHz band (i.e., information about the preamble puncturing pattern).

[0167] As an addition or alternative, the U-SIG and EHT-SIG may include information on preamble puncturing based on the following methods: The U-SIG may include information on preamble puncturing for the entire bandwidth (i.e., information on the preamble puncturing pattern). That is, the EHT-SIG may not include information on preamble puncturing, and only the U-SIG may include information on preamble puncturing (i.e., information on the preamble puncturing pattern).

[0168] U-SIGs may be configured in 20MHz units. For example, when an 80MHz PPDU is configured, U-SIGs may be duplicated. That is, an 80MHz PPDU may contain four identical U-SIGs. PPDUs with a bandwidth exceeding 80MHz may contain different U-SIGs.

[0169] The EHT-SIG in Figure 13 may contain control information for the receiving STA. The EHT-SIG may be transmitted with at least one symbol, which may have a length of 4us. Information regarding the number of symbols used for the EHT-SIG may be included in the U-SIG.

[0170] 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 common fields and user-specific fields, identical to the example in Figure 8. The common fields of the EHT-SIG may be omitted, and the number of user-specific fields may be determined based on the number of users.

[0171] As in the example in Figure 11, the common fields and user-specific fields of the EHT-SIG may be coded separately. One user block field included in the user-specific field contains information for two user fields, but the last user block field included in the user-specific field may contain one or two user fields. That is, one user block field of the EHT-SIG may contain a maximum of two user fields. As in the example in Figure 12, each user field may be related to MU-MIMO assignment or non-MU-MIMO assignment.

[0172] Similar to the example in Figure 11, the common field of the EHT-SIG may include a CRC bit and a Tail bit, the length of the CRC bit may be determined to be 4 bits, and the length of the Tail bit may be determined to be 6 bits and set to 000000.

[0173] As in the example shown in Figure 11, the common fields of the EHT-SIG may include RU allocation information. RU allocation information can represent information about the location of RUs to which multiple users (i.e., multiple receiving STAs) are assigned. RU allocation information may consist of 9-bit (or N-bit) units.

[0174] A mode in which the common field of the EHT-SIG is omitted may be supported. This mode in which the common field of the EHT-SIG is omitted can be called compressed mode. When 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 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.

[0175] The EHT-SIG may be constructed based on various MCS techniques. As mentioned above, information regarding the MCS technique applied to the EHT-SIG may be included in the U-SIG. The EHT-SIG may be constructed based on the DCM technique. The DCM technique can provide an effect similar to frequency diversity by reusing the same signal on two subcarriers, thereby reducing interference and improving coverage. For example, modulation symbols with the same modulation technique applied may be repeatedly mapped on available tones / subcarriers. For example, of the N data tones allocated for the EHT-SIG (e.g., 52 data tones), the first half of the consecutive tones (e.g., tones 1-26) may be mapped to modulation symbols with a specific modulation technique applied (e.g., BPSK modulation symbols), and the remaining half of the consecutive tones (e.g., tones 27-52) may be mapped to modulation symbols with the same specific modulation technique applied (e.g., BPSK modulation symbols). In other words, the modulation symbol mapped to the first tone and the modulation symbol mapped to the 27th tone are identical. As mentioned above, information (e.g., a 1-bit field) regarding whether or not the DCM method is applied to the EHT-SIG may be included in the U-SIG. The EHT-STF in Figure 13 may be used to improve automatic gain control (AGC) estimation in a MIMO or OFDMA environment. The EHT-LTF in Figure 13 may be used to estimate the channel in a MIMO or OFDMA environment.

[0176] Information regarding the type of STF and / or LTF (including information regarding the GI (guard interval) applied to the LTF) may be included in the U-SIG field and / or EHT-SIG field in Figure 13, etc.

[0177] The PPDU in Figure 13 (i.e., the EHT PPDU) may be configured based on the example RU configurations in Figures 8 to 10.

[0178] For example, an EHT PPDU transmitted over a 20MHz bandwidth, i.e., a 20MHz EHT PPDU, may be configured based on the RUs in Figure 8. That is, the locations of the RUs for the EHT-STF, EHT-LTF, and data field included in the EHT PPDU may be determined as shown in Figure 8. An EHT PPDU transmitted over a 40MHz bandwidth, i.e., a 40MHz EHT PPDU, may be configured based on the RUs in Figure 9. That is, the locations of the RUs for the EHT-STF, EHT-LTF, and data field included in the EHT PPDU may be determined as shown in Figure 9.

[0179] An EHT PPDU transmitted over the 80MHz band, i.e., an 80MHz EHT PPDU, may be constructed based on the RUs in Figure 10. That is, the locations of the RUs for the EHT-STF, EHT-LTF, and data field included in the EHT PPDU may be determined as shown in Figure 10. The tone-plan for 80MHz in Figure 10 may correspond to two iterations of the tone-plan for 40MHz in Figure 9.

[0180] The tone plan for 160 / 240 / 320MHz may consist of multiple repetitions of the pattern shown in Figure 9 or Figure 10.

[0181] The PPDU in Figure 13 may be identified as an EHT PPDU based on the following method.

[0182] The receiving STA can determine the type of the received PPDU to be an EHT PPDU based on the following: For example, the received PPDU may be determined to be an EHT PPDU if 1) the first symbol after the L-LTF signal of the received PPDU is BPSK, 2) an RL-SIG is detected in which the L-SIG of the received PPDU is repeated, and 3) the result of applying modulo 3 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 to be 0. When the received PPDU is determined to be an EHT PPDU, the receiving STA can determine the type of the EHT PPDU based on the bit information contained in the symbol after the RL-SIG in Figure 13. In other words, the receiving STA can determine the received PPDU to be an EHT PPDU based on 1) the first symbol after the L-LTF signal which is BSPK, 2) an RL-SIG that is consecutive to the L-SIG field and identical to the L-SIG, and 3) an L-SIG that contains a Length field in which the result of applying modulo 3 is set to 0.

[0183] For example, a receiving STA can determine the type of the received PPDU to be HE PPDU based on the following: For example, if 1) the first symbol after the L-LTF signal is BPSK, 2) an RL-SIG consisting of repeated L-SIGs is detected, and 3) the result of applying modulo 3 to the Length value of the L-SIG is detected to be 1 or 2, then the received PPDU may be determined to be HE PPDU.

[0184] For example, a receiving STA can determine the type of the received PPDU to be 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) no RL-SIG (where L-SIG is repeated) is detected, the received PPDU may be determined to be non-HT, HT, or VHT PPDU.

[0185] Furthermore, if the receiving STA detects an RL-SIG in which the L-SIG is repeated from the received PPDU, it can determine that it is an HE PPDU or an EHT PPDU. In this case, if the rate (6Mbps) check fails, the received PPDU may be determined to be a non-HT, HT, or VHT PPDU. If the rate (6Mbps) check and parity check pass, and the result of applying modulo 3 to the Length value of the L-SIG is detected as 0, the received PPDU may be determined to be an EHT PPDU, and if the result of Length mod 3 is not 0, it may be determined to be an HE PPDU.

[0186] The PPDU in Figure 13 may be used to send and receive various types of frames. For example, the PPDU in Figure 13 may be used to send and receive one or more (simultaneous) control frames, management frames, or data frames.

[0187] The following provides a more detailed explanation of U-SIGs included in the EHT PPDU.

[0188] For 40MHz EHT PPDU or ER (Extended Range) preambles, the U-SIG content is identical across two 20MHz subchannels. For 80MHz EHT PPDU or ER preambles, the U-SIG content is identical across all non-punctured 20MHz subchannels. For 160 / 320MHz EHT PPDU or ER preambles, the U-SIG content is identical across all non-punctured 20MHz subchannels within each 80MHz subblock, and may differ from the U-SIG content in other 80MHz subblocks.

[0189] The U-SIG-1 part of the U-SIG of the EHT MU PPDU may include the PHY version identifier (B0-B2), BW (B3-B5), UL / DL (B6), BSS color (B7-B12), and TXOP (B13-B19), while the U-SIG-2 part may include the PPDU type and compression mode (B0-B1), validate (B2), punctured channel information (B3-B7), validate (B8), EHT-SIG MCS (B9-B10), number of EHT-SIG symbols (B11-B15), CRC (B16-B19), and tail (B20-B25).

[0190] Next, the U-SIG-1 part of the U-SIG for the EHT TB PPDU may include the version identifier (B0-B2), BW (B3-B5), UL / DL (B6), BSS color (B7-B12), TXOP (B13-B19), and disregard (B20-B25), while the U-SIG-2 part may include the PPDU type and compression mode (B0-B1), validate (B2), spatial reuse 1 (B3-B6), spatial reuse 2 (B7-B10), disregard (B11-B15), CRC (B16-B19), and tail (B20-B25).

[0191] As mentioned above, the U-SIG field of the EHT MU PPDU contains 5-bit punctured channel information, while the EHT TB PPDU does not contain punctured channel information. This is because it is assumed that the EHT TB PPDU is configured according to resource allocation indicated by the trigger frame or TRS control information, and therefore the STA did not need to inform the AP of the resource information of the EHT TB PPDU.

[0192] Furthermore, even if an STA receives a trigger frame or TRS control information as described above, it does not have to respond with an HE TB PPDU. For example, a non-AP STA may choose not to respond to a trigger frame if one or more subfields of a common information field included in the trigger frame or a user field addressed to or selected by the non-AP STA have values ​​that are not recognized, supported, or satisfied. Similarly, a non-AP STA may choose not to respond to a TRS control subfield if the TRS control subfield included in a frame addressed to the non-AP STA has values ​​that are not recognized, supported, or satisfied by the non-AP STA.

[0193] Target wake time (TWT)

[0194] TWT is a Power Saving (PS) technology that improves the energy efficiency of non-AP STAs by defining the Service Period (SP) between APs and non-AP STAs, sharing information about the SPs with each other, and reducing contention of the medium.

[0195] A TWT Setup (TWT) Setup (STA) that makes a request / suggestion / demand can be called a TWT Requesting (STA). An AP (Application Partner) that responds to such a request (acceptance / rejection) can be called a TWT Responding (STA).

[0196] The setup phase may include the process of determining / defining the TWT request from the STA to the AP, the type of TWT operation to be performed, and the type of frames to be sent and received. TWT operations can be divided into individual TWTs and broadcast TWTs.

[0197] Figure 14 is a diagram illustrating an example of individual TWT operation to which this disclosure can be applied.

[0198] Individual TWT is a mechanism in which AP and non-AP STA negotiate the activation / doze status of the non-AP STA through the sending and receiving of TWT Request / Response frames, and then exchange data.

[0199] In the example shown in Figure 14, AP and STA1 can form a trigger-enabled TWT agreement via a TWT request frame and a TWT response frame.

[0200] In this case, the method used by STA1 is a solicited TWT method, in which STA1 sends a TWT request frame to the AP, and STA1 receives information for TWT operation from the AP using a TWT response frame.

[0201] On the other hand, STA2, which uses an unsolicited TWT scheme, can receive information from AP regarding the setting of a trigger-enabled TWT agreement using an unsolicited TWT response.

[0202] 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 send a trigger frame to the STA. The trigger frame can inform the STA that the AP has buffered data. In response, STA1 can inform the AP of its awake state by sending a PS-Poll frame. STA2 can also inform the AP of its awake state by sending a QoS Null frame. Here, the data frames sent by STA1 and STA2 may be in TB PPDU format. The AP, having confirmed the status of STA1 and STA2, can send a DL MU PPDU to the awake STA. When the TWT SP expires, STA1 and STA2 may switch to a doze state.

[0203] Figure 15 illustrates an example of a broadcast TWT operation to which this disclosure can be applied.

[0204] A broadcast TWT is a type of TWT in which a non-AP STA (or TWT scheduling STA) obtains information such as TBTT (target beacon transmission time) and listen interval by sending and receiving TWT request / response frames with an AP (or TWT scheduled STA). Negotiation operations regarding TBTT may also be performed. Based on this, the AP can define a frame containing TWT scheduling information using a beacon frame.

[0205] In Figure 15, STA1 performs a requested TWT operation, and STA2 performs an unrequested TWT operation. The AP can send a DL MU PPDU after confirming the awake state of the STA using the trigger it sent. This may be the same as the process for individual TWTs. In a broadcast TWT, the trigger-enabled TWT SP, which includes a beacon frame, may be repeated multiple times at regular intervals.

[0206] TWT information may be transmitted through TWT information frames and TWT information elements. TWT information frames are transmitted by STAs to request or transmit information about a TWT agreement and are transmitted by one of the STAs of an existing TWT agreement. The action field of a 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.

[0207] Figure 16 is a diagram illustrating an example of the TWT information element format.

[0208] TWT elements may be transmitted and received as part of beacons, probe responses, (re)connection response frames, etc. A TWT element may include an element ID field, a length field, a control field, and a TWT parameter information field.

[0209] The control field of a TWT element has the same format regardless of whether it is an individual TWT or a broadcast TWT.

[0210] The NDP paging indication subfield may have a value of 1 if the NDP paging field exists, and a value of 0 if the NDP paging field does not exist.

[0211] The Responder PM mode subfield can indicate the Power Management (PM) mode.

[0212] The negotiation type subfield can indicate whether the information contained in the TWT element pertains to the negotiation of parameters for a broadcast TWT or individual TWT(s), or to the wake TBTT interval.

[0213] For example, if the value of the negotiation type subfield is 0, the TWT subfield relates to the future individual TWT SP start time, and the TWT element contains one individual TWT parameter set. This corresponds to an individual TWT negotiation between a TWT requesting STA and a TWT responding STA, or an individual TWT by a TWT responder. Announcement This could be considered an announcement.

[0214] For example, if the value of the negotiation type subfield is 1, the TWT subfield relates to the next TBTT time, and the TWT element contains one separate TWT parameter set. This could correspond to a wake TBTT and wake interval negotiation between a TWT-scheduled STA and a TWT-scheduling AP.

[0215] For example, if the value of the negotiation type subfield is 2, the TWT subfield relates to the future broadcast TWT SP start time, and the TWT element contains one or more broadcast TWT parameter sets. This may constitute providing a broadcast TWT schedule to the TWT-scheduled STA by including the TWT element in the broadcast management frame sent by the TWT scheduling AP.

[0216] For example, if the value of the negotiation type subfield is 3, the TWT subfield relates to the future broadcast TWT SP start time, and the TWT element contains one or more broadcast TWT parameter sets. This may constitute managing membership in a broadcast TWT schedule by including the TWT element in an individually addressed management frame sent by either the TWT-scheduled STA or the TWT-scheduling AP.

[0217] When the TWT information frame disabled subfield is set to 1, it indicates that the STA will be disabled from receiving TWT information frames; otherwise, it may be set to 0.

[0218] The Wake Duration Unit subfield indicates the unit of the Nominal Minimum TWT Wake Duration field. The Wake Duration Unit subfield may be set to 0 if the unit is 256us, and to 1 if the unit is TU. The Wake Duration Unit subfield may be set to 0 if it is not HE / EHT STA.

[0219] The MSB (most significant bit) of the negotiation type field may correspond to the broadcast field. If the broadcast field is 1, the TWT element may contain one or more broadcast TWT parameter sets. If the broadcast field is 0, the TWT element may contain only one individual TWT parameter set. A TWT element in which the broadcast field is set to 1 can be called a broadcast TWT element.

[0220] Figure 16 shows a case where the reserved field consists of 2 bits, but this is just one example. For example, a TWT element may include a Link ID bitmap present field (e.g., 1 bit) and a reserved field (e.g., 1 bit).

[0221] For example, if the Link ID Bitmap Existence field is set to 1, the Individual TWT Parameter Set Field Format described later may be configured to have a Link ID Bitmap subfield, and if the Link ID Bitmap Existence field is set to 0, the Individual TWT Parameter Set Field Format may be configured not to have a Link ID Bitmap subfield.

[0222] Figure 17 is a diagram illustrating an example of an individual TWT parameter set field format. Figure 18 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 Figure 16 may have different configurations depending on whether it is an individual TWT or a broadcast TWT.

[0224] When it is an individual TWT, the TWT parameter information field within the TWT element includes a single individual TWT parameter set field.

[0225] If it is a broadcast TWT, the TWT parameter information field within the TWT element includes one or more broadcast TWT parameter set fields. Each broadcast TWT parameter set may contain specific information about a single broadcast TWT.

[0226] As shown in Figures 17 and 18, the individual TWT parameter set field and the broadcast TWT parameter set field include common subfields.

[0227] The request type subfield may be the same size in the individual TWT parameter set field and the broadcast TWT parameter set field, but its detailed configuration may differ from one another. This will be explained later.

[0228] The Target Wake Time subfield indicates the start time of any subsequent individual / broadcast TWT SPs.

[0229] The nominal maximum TWT wake duration subfield indicates the smallest unit that a TWT requesting STA expects to wake up in the TWT wake interval duration to complete a frame exchange associated with a TWT flow identifier. Here, the TWT wake interval can mean the average time between consecutive TWT SPs expected by the TWT requesting STA.

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

[0231] Referring to Figure 17, the TWT group assignment subfield, TWT channel, and NDP paging subfield are included only 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 has been assigned. This information can be used to calculate the TWT value within the TWT group. The STA's TWT value may be the same as the value obtained by multiplying the zero offset value by the TWT offset value and the TWT unit value.

[0233] The TWT Channel subfield indicates a bitmap showing the allowed channels. When transmitted by a TWT Requesting STA, the TWT Channel subfield may include a bitmap showing the channels that the STA requests to be used as temporary basic channels in the TWT SP. When transmitted by a TWT Responseing STA, the TWT Channel subfield may include a bitmap showing the channels on which the TWT Request is allowed.

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

[0235] Referring to Figure 18, 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 reservation 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 particular broadcast TWT that the STA requests to participate in or provides TWT parameters for, based on the value of the TWT setup command subfield of the TWT element. The broadcast TWT persistence subfield indicates the number of TBTTs planned on the broadcast TWT schedule.

[0236] Next, we will explain the detailed structure of the request type subfield.

[0237] First, with reference to Figure 17, we will describe the format of the request type subfield of the individual TWT parameter set field.

[0238] The TWT request subfield can indicate whether it is a requesting STA or a response STA. A value of 1 indicates a TWT requesting STA or a scheduled STA, while a value of 0 indicates a TWT response STA or a scheduling AP.

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

[0240] The trigger subfield indicates whether or not to use trigger frames in TWT SP. A value of 1 means triggers are used, and a value of 0 means triggers are not used.

[0241] An implicit subfield can indicate whether a TWT is implicit or explicit. A value of 1 indicates an implicit TWT, while a value of 0 indicates an 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 response STA (or an AP that TWT-schedules). If its value is 1, the STA sends a PS-Poll or APSD (automatic power save delivery) trigger frame and a wake-up signal to the AP before any frames other than the trigger frame are sent from the AP to the STA. Announcement It can mean type (announced)TWT. If its value is 0, it is not Announcement It can be interpreted as type TWT.

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

[0244] The TWT wake interval exponent subfield allows you to set the TWT wake interval value in binary microseconds. In the case of individual TWTs, it can represent the interval between individual TWT SPs. The TWT wake interval of a requested STA may be defined as [TWT Wake Interval Mantissa*2*TWT Wake Interval Exponent].

[0245] The TWT protection subfield can indicate whether or not a TWT protection mechanism is used. If its value is 1, the TXOP within the TWT SP may be started with a NAV protection mechanism such as (MU)RTS / CTS or CTS-to-self frames; if it is 0, no NAV protection mechanism is required.

[0246] Referring to Figure 18, some of the subfields of the request type subfield of the broadcast TWT parameter set field are common with the subfields of the request type subfield of the individual TWT parameter set field, so their explanation will be omitted. The subfields that are included only in the broadcast TWT parameter set are described below.

[0247] The Last Broadcast Parameter Set subfield indicates whether it is the last broadcast TWT parameter set. A value of 1 indicates that it is the last broadcast TWT parameter set, while a value of 0 indicates that the next broadcast TWT parameter set exists.

[0248] The Broadcast TWT Recommendation subfield can indicate a recommendation for the frame type sent by the AP in a Broadcast TWT SP, with a value from 1 to 7.

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

[0250] The following describes the low-latency transmission methods related to this disclosure for supporting latency-sensitive traffic.

[0251] In recent years, while wired and wireless traffic have surged, latency-sensitive traffic has also increased significantly. Latency-sensitive traffic includes real-time audio / video transmission, and the proliferation of multimedia equipment has increased the need to support it in wireless environments. However, supporting latency-sensitive traffic in wireless environments presents more challenges than in wired environments. This is because wireless environments have lower transmission speeds and must also consider interference issues from the surrounding area. In particular, in wireless LAN systems, numerous STAs must compete equally for media occupancy in the ISM (Industry-Science-Medical) band, making it relatively more difficult to support latency-sensitive traffic compared to cellular communication networks based on wireless resource scheduling by a central base station. This disclosure describes a new approach to supporting latency-sensitive traffic in wireless LAN systems.

[0252] In this disclosure, latency can mean latency as defined in the IEEE 802.11 series standards. For example, it can mean the time from when a frame to be transmitted enters the MAC layer queue of the transmitting STA, until the transmission by the transmitting STA is successfully completed at the PHY layer, the transmitting STA receives an ACK / block ACK from the receiving STA, and the frame is deleted from the transmitting STA's MAC layer queue.

[0253] Furthermore, in this disclosure, a non-AP STA that supports the transmission of latency-sensitive data may be referred to as a Low Latency STA. Data other than latency-sensitive data may be referred to as regular data.

[0254] The restricted TWT will be described below with reference to Figure 19.

[0255] Restricted TWTs (r-TWTs) can help ensure that low-latency STAs have priority over other STAs by setting up special broadcast TWTs for low-latency STAs that transmit latency-sensitive data. An STA can establish membership to one or more r-TWT schedules with respect to the AP.

[0256] Here, the r-TWT agreement may be established by the same process as the broadcast TWT agreement, and for that purpose, the broadcast TWT element may be defined to include the r-TWT parameter set field. For example, the r-TWT parameter set may refer to a specific broadcast TWT parameter set field that is distinguishable from other broadcast TWT parameter set fields. That is, the r-TWT parameter set field may be a special case of a broadcast TWT parameter set field. Also, AP may define the r-TWT SP as Announcement (Announce) is possible.

[0257] In this disclosure, as described above, non-AP STAs that support the transmission of latency-sensitive data may be referred to as low-latency STAs, and data that is not latency-sensitive may be referred to as regular data.

[0258] As an addition or alternative, a low-latency STA associated with a specific r-TWT will be referred to as a member r-TWT scheduled STA, and other STAs will be referred to as non-member STAs. A non-member STA may have the capacity to support r-TWT operations / TWT operations (e.g., individual TWTs and / or broadcast TWTs), but may not be a member of any r-TWT, may be a member of another r-TWT while supporting an r-TWT operation / TWT operation, or may not possess the capacity to support an r-TWT operation / TWT operation.

[0259] An STA (e.g., a low-latency STA) supporting a restricted SP (or r-TWT SP) operation of a broadcast TWT can inform the AP that it must transmit latency-sensitive data based on the r-TWT operation. If the AP supports the r-TWT operation / mode, the AP can send frames to the low-latency STA and other STAs containing the TWT scheduling information requested by each STA. For example, to perform an operation for an r-TWT, a non-AP STA can obtain r-TWT-related information from the AP using beacon frames, probe response frames, (re)connection response frames, or other undefined format frames (e.g., broadcast, advertisement, public use frames).

[0260] According to r-TWT operation, another TXOP (i.e., access by other STAs is restricted) may be secured (or executed) within an r-TWT SP using a NAV such as (MU)RTS / CTS or CTS-to-self, or a quiet interval. If there are TXOPs of other STAs (i.e., non-member STAs) other than those that are members of the particular r-TWT schedule before a particular r-TWT SP starts, they must be stopped. The TXOPs of the other STAs (i.e., non-member STAs) may then be performed after the particular r-TWT SP has finished. This can be referred to as TXOP rule-based operation of non-member STAs to r-TWT SPs. Such r-TWT TXOP rules enable more predictable low-latency services for latency-sensitive data.

[0261] Conditional execution method of r-TWT

[0262] According to the TXOP rules for r-TWT mentioned above, Announcement At the same time as supporting the r-TWT SP, the said r-TWT SP Announcement An EHT non-AP associated with the AP must terminate its TXOP before the r-TWT SP starts.

[0263] This disclosure describes additional execution conditions for the r-TWT SP TXOP rule described above. This allows the r-TWT SP TXOP rule to provide the intended predictable low-latency service and improve the efficiency of latency-sensitive data / traffic transmission in a manner that does not interfere with the existing data transmission flow.

[0264] Figure 20 is a diagram illustrating the restricted TWT operation of a first STA according to an example of the present disclosure. In Figures 20 and 21, the first STA is an EHT non-AP STA (coupled to an AP), and the second STA is an AP, but is not limited thereto.

[0265] The first STA can perform the restricted target wake time (r-TWT) membership setup procedure with the second STA (S2010).

[0266] The r-TWT membership setup procedure may be established in the same way as the broadcast TWT membership procedure. However, in the r-TWT membership setup procedure, the broadcast TWT element transmitted on the TWT setup frame may include one or more r-TWT parameter set fields.

[0267] A second STA (e.g., an r-TWT scheduling AP) and a first STA (e.g., an R-TWT scheduled STA) can configure r-TWT traffic information fields to identify TIDs that transmit delay-sensitive traffic in DL and UL for the set up r-TWT membership. That is, the first and second STAs may configure at least one r-TWT DL TID or at least one r-TWT UL TID.

[0268] In the r-TWT traffic information field, TIDs indicated as delay-sensitive traffic in DL and UL can be collectively referred to as r-TWT TIDs. In the r-TWT traffic information field, TIDs indicated as delay-sensitive traffic in DL and UL may be located within the TID sets mapped to DL and UL, respectively.

[0269] In the following, the TID specified in the r-TWT traffic information field of the TWT element in a TWT response frame indicating an Accept TWT will be referred to as R-TWT DL TID(s) or R-TWT UL TID(s).

[0270] The first STA can receive r-TWT schedule information contained in the broadcast TWT element from the second STA (S2020).

[0271] Specifically, if a configured r-TWT membership exists, the second STA includes the r-TWT parameter set field in the broadcast TWT element contained in the transmitted management frame, thereby providing the r-TWT schedule information. Announcement It is possible.

[0272] As an example, the first piece of information can be received in the beacon frame and / or probe response frame, which will contain r-TWT schedule information.

[0273] As an example of this disclosure, r-TWT schedule information Announcement Based on that a specific portion of the first TXOP within the established r-TWT SP is not used for delivery of DL frames corresponding to at least one r-TWT downlink (DL) TID or solicitation of UL frames corresponding to at least one r-TWT uplink (UL) TID, the first TXOP may end before the start time of the r-TWT SP.

[0274] Specifically, for the r-TWT SP Announcement when the second STA that [...] is the holder of the first TXOP, if a specific portion of the first TXOP is not used for delivery of DL frames corresponding to at least one r-TWT DL TID or solicitation of UL frames corresponding to at least one r-TWT UL TID, the second STA can ensure that the first TXOP ends before the start time of the r-TWT SP.

[0275] That is, if a specific portion of the first TXOP is not used for frame transmission and reception corresponding to at least one r-TWT DL TID or at least one r-TWT UL TID, the second STA can ensure that the first TXOP ends before the start time of the r-TWT SP.

[0276] As yet another example, based on that a specific portion of the first TXOP is used for delivery of DL frames corresponding to at least one r-TWT DL TID or solicitation of UL frames corresponding to at least one r-TWT UL TID, the first TXOP does not need to end even after the start time of the r-TWT SP.

[0277] The end time of r-TWT SP may be delayed based on the fact that the first TXOP does not terminate after the start time of r-TWT SP. For example, if the first TXOP does not terminate after the start time of r-TWT SP, the end time of r-TWT SP may be delayed by the amount of time the r-TWT SP is delayed.

[0278] As an additional or alternative, the maximum time by which the end time of an r-TWT SP may be delayed may be set / indicated / defined with the (start) time value of the delayed r-TWT SP.

[0279] As yet another example of this disclosure, based on the fact that the first STA is the holder of the second TXOP, the second TXOP is owned by the second STA. Announcement The r-TWP SP may be terminated before the start of the r-TWP SP. That is, the first STA is terminated when the second TXOP is performed by the second STA. Announcement It can be guaranteed that the r-TWT SP will terminate before the start point.

[0280] Figure 21 is a diagram illustrating the restricted TWT operation of a second STA according to an example of this disclosure.

[0281] The second STA can perform the restricted target wake time (r-TWT) membership setup procedure with the first STA (S2110).

[0282] For example, the second STA can set the trigger field value to 1 in the r-TWT parameter set field to be transmitted.

[0283] The second STA can transmit the r-TWT schedule information contained in the broadcast TWT element to the first STA (S2120).

[0284] Specifically, if a configured r-TWT membership exists, the second STA includes the r-TWT parameter set field in the broadcast TWT element to provide the r-TWT schedule information. Announcement It is possible.

[0285] The operations and parameters related to S2110 and S2120 correspond to the operations and parameters related to S2010 and S2020, and therefore redundant explanations are omitted.

[0286] The following describes in detail the conditional execution method of r-TWT related to this disclosure. Specifically, the conditional TXOP rule of r-TWT SP, which reflects additional conditions to the TXOP rule of r-TWT SP described above, will be described. One or more STAs can operate according to one or more of the embodiments described below.

[0287] Example 1

[0288] Example 1 describes a method for executing a conditional TXOP rule for r-TWT SP based on data priority.

[0289] From AP Announcement At the same time as supporting the r-TWT SP, Announcement An EHT non-AP STA associated with the said AP may have a rule defined that it should terminate its TXOP before the start of the said r-TWT SP. However, such rule may only be enforced / applied if the data that the STA (e.g., the said EHT non-AP STA and / or AP) transmits in the TXOP is not data that should be transmitted more urgently than delay-sensitive data.

[0290] That is, when the data transmitted by the STA (for example, the EHT non-AP STA or / and AP) in the TXOP is data that needs to be transmitted more urgently than delay-sensitive data, the rule may be applied / executed.

[0291] Specifically, the rule may be applied / executed only when a specific condition is satisfied, and the specific condition may be set / defined as one of the options described later.

[0292] Option 1

[0293] When the data to be transmitted in the TXOP does not belong to any TID classified as latency traffic, the aforementioned TXOP rule may be applied / executed.

[0294] That is, when the data to be transmitted in the TXOP does not belong to any TID classified as latency traffic, the STA (for example, the EHT non-AP STA or / and AP) may terminate the TXOP when the r-TWT SP starts.

[0295] And when the data to be transmitted in the TXOP belongs to any TID classified as latency traffic, the STA (for example, the EHT non-AP STA or / and AP) can continue transmitting the data without terminating the TXOP (even after the start time of the r-TWT SP has passed).

[0296] Option 2

[0297] When the data to be transmitted in the TXOP is traffic having a lower priority than the latency traffic specified in the r-TWT SP (that is, when the data to be transmitted in the TXOP is not data that needs to be transmitted more urgently than delay-sensitive data), the aforementioned TXOP rule may be applied / executed.

[0298] In other words, if the data transmitted by TXOP is traffic with a lower priority than the delayed traffic specified in the r-TWT SP, the STA (e.g., the EHT non-AP STA and / or AP) may terminate the TXOP when the r-TWT SP begins.

[0299] Furthermore, if the data transmitted by TXOP has a higher priority than or equal priority to the delayed traffic specified by the r-TWT SP, the STA (e.g., the EHT non-AP STA and / or AP) may continue transmitting the data without terminating the TXOP (even after the start time of the r-TWT SP has elapsed).

[0300] Option 3

[0301] The above-described TXOP rules may be applied / executed when the data transmitted via TXOP belongs to a specific AC.

[0302] In other words, if the data transmitted via TXOP is a specific AC, the STA (e.g., the EHT non-AP STA and / or AP) may terminate the TXOP when the r-TWT SP begins. However, if the data transmitted via TXOP is another AC that is not a specific AC (e.g., AC_VO or AC_VI), the STA (e.g., the EHT non-AP STA and / or AP) may continue transmitting the data without terminating the TXOP (even after the start time of the r-TWT SP has elapsed).

[0303] Here, the specific AC may be, but is not limited to, AC_BE or AC_BK. For example, the TXOP rules described above may also apply / execute when the data transmitted via TXOP is AC_VI.

[0304] Example 2

[0305] Example 2 relates to a method for executing a conditional TXOP rule for an r-TWT SP based on the importance of the data sent and received by an STA that has negotiated the r-TWT SP.

[0306] From AP Announcement At the same time as supporting the r-TWT SP, the said r-TWT SP Announcement The TXOP rules may be defined such that the EHT non-AP STA coupled to the AP terminates the TXOP before the start of the r-TWT SP.

[0307] However, the TXOP rule may be applied / executed only if, during r-TWT setup, the data sent to the TXOP is not data designated as delay-sensitive data / traffic by the UL / DL TID negotiated by the STA (e.g., EHT non-AP STA and / or AP).

[0308] In other words, if the data transmitted to the TXOP is data designated as delay-sensitive data / traffic by the UL / DL TID negotiated by the STA (e.g., EHT non-AP STA and / or AP), the STA does not need to terminate the TXOP even after the start of the r-TWT SP.

[0309] Specifically, while supporting r-TWT, STAs that have the same broadcast TWT ID will receive information about the r-TWT SP from the AP. Announcement This is permissible. APs and STAs proceeding with r-TWT setup to be assigned r-TWT SPs can negotiate for latency-sensitive data / traffic using UL / DL TID.

[0310] This allows APs and STAs assigned to r-TWT SPs to share TID information that implies / indicates that the data / traffic is delay-sensitive at the r-TWT SP. Under the conditions described above, when an STA transmits data with a TID that has been implied / indicated as delay-sensitive data / traffic (by the scheduled r-TWT SP), it does not need to abort its TXOP before the r-TWT SP starts.

[0311] Figures 22 and 23 illustrate the process by which the conditional TXOP rule for r-TWT SP according to Example 2 is applied.

[0312] RSP STA 1, RSP STA 2, and RSP STA 3, which are RSP STAs (STAs that support r-TWT SP), can all perform the TWT setup process. However, Figures 22 and 23 illustrate the process in which RSP STA 2 performs the TWT setup procedure and the process in which AP and RSP STA 2 establish membership.

[0313] Specifically, Figures 22 and 23 show that the AP sends TWT information to one or more RSP STAs in a beacon frame. Announcement This illustrates how an RSP STA that receives the TWT information sends a TWT request based on the broadcast TWT ID corresponding to the desired TWT.

[0314] As a result, RSP STA 1, RSP STA 2, and RSP STA 3 can all have the same broadcast TWT ID. RSP STA 1 can classify data corresponding to TID 0, 1, and 2 as delay-sensitive data / traffic. RSP STA 2 and RSP STA 3 can classify data corresponding to TID 0, 4, and 5 as delay-sensitive data / traffic.

[0315] If the beacon frame transmitted by AP contains information about the r-TWT SP assigned to RSP STA3, the data classified as delay-sensitive data / traffic (DL / UL) by that r-TWT SP may be data corresponding to TIDs 0, 4, and 5. If RSP STA 2 transmits data corresponding to TIDs 0, 4, and 5 before the start of that r-TWT SP, RSP STA 2 can complete the transmission and reception of data corresponding to TIDs 0, 4, and 5 without aborting its TXOP before the r-TWT SP.

[0316] Here, r-TWT SP may be extended only for the time interval from the start of r-TWT SP to the completion of TXOP. That is, r-TWT SP may start from the time TXOP is completed, and said r-TWT SP may be extended only for the aforementioned time interval. Additionally or alternatively, the maximum time by which the end time of r-TWT SP may be delayed may be set / instructed / defined as the (start) time value of the delayed r-TWT SP.

[0317] Example 3

[0318] Example 3 relates to a method for conditionally executing / applying the above-mentioned TXOP rules by a TXOP holder.

[0319] From AP Announcement At the same time as supporting the r-TWT SP, the said r-TWT SP Announcement An EHT non-AP STA connected to the AP must terminate its TXOP before the r-TWT SP starts. However, if the EHT non-AP STA is an EHT non-AP STA that has been assigned a publicly known r-TWT SP from the AP, it does not need to stop / terminate its TXOP.

[0320] Existing r-TWT TXOP rules define the behavior of unconditionally stopping any TXOP in progress before an r-TWT SP begins when an r-TWT SP starts, so that delay-sensitive data / traffic transmission and reception operations can be safely completed within the r-TWT SP.

[0321] However, if the holder of a TXOP that was in progress before the r-TWT SP is the same as the STA to which the r-TWT SP is assigned, the STA does not need to interrupt its TXOP before the start of the r-TWT SP. In other words, the STA can efficiently complete the transmission and reception of latency-sensitive data / traffic within the r-TWT SP while maintaining its TXOP.

[0322] Figures 24 and 25 illustrate the process by which the conditional TXOP rule for r-TWT SP according to Example 3 is applied.

[0323] Figures 24 and 25 illustrate the process by which AP and RSP STA 2 establish membership. AP sends TWT information in a beacon frame. Announcement Upon receiving the TWT information, the STA can then send a TWT request to the AP based on the broadcast TWT ID corresponding to the desired TWT.

[0324] If the beacon frame transmitted by AP contains information about the r-TWT SP (RSP) assigned to RSP STA 2, then RSP STA 2 may be a TXOP holder that transmits data with its TXOP before the scheduled r-TWT SP.

[0325] In this case, when the conditional TXOP rule according to Example 3 is applied, the scheduled r-TWT SP is the r-TWT SP assigned to RSP STA 2, so RSP STA 2 can send and receive (UL / DL) delay-sensitive traffic within the r-TWT SP without terminating its TXOP.

[0326] Example 4

[0327] At least one of Examples 1, 2, or 3 described above may be applied to the TXOP rules for r-TWT SPs. Example 4 relates to a method by which an AP can inform other STAs of the TXOP rules for r-TWT SPs to which the above examples have been applied.

[0328] In the case of an unsolicited method, the AP will receive beacon frames, (broadcast) probe response frames, and other (and / or new) Announcement Information regarding the above-described embodiment can be communicated to other STAs using (or / and broadcast) frames.

[0329] Figures 26 and 27 illustrate the process by which AP informs other STAs of the above-described embodiment.

[0330] Specifically, Figure 26 illustrates the execution of r-TWT when regular data is more urgent than delay-sensitive data (or / and regular data has a higher priority than delay-sensitive data). Figure 27 illustrates the execution of r-TWT when delay-sensitive data is more urgent than regular data (or / and delay-sensitive data has a higher priority than regular data).

[0331] As an addition or alternative, as shown in Figure 28, the terminal and AP can exchange information about the embodiment through negotiation procedures (e.g., probe request procedure, probe response procedure, join request procedure, join response procedure, new request procedure, and new response procedure). Here, the probe / join / new request / response procedure can mean the procedure for sending and receiving probe / join / new request / response frames.

[0332] During the negotiation process, information regarding latency traffic (e.g., real-time gaming, cloud gaming, real-time video, robotics and industrial automation, etc.) and whether or not each AP / STA supports r-TWT SP may be exchanged.

[0333] This allows the AP and low-latency STA to set up an optimal environment for transmitted latency-sensitive traffic. As an example, the transmission and reception of the above-mentioned information may be performed by at least one of the methods described later.

[0334] Method 1: AP and low-latency STA can exchange the above information in a single request and response procedure during the negotiation process.

[0335] Method 2: The AP and low-latency STA can transmit the above information over (or separately) i) the probe request procedure and probe response procedure, and ii) the coupling request procedure and coupling response procedure.

[0336] Method 3: The above information may be exchanged by a separate new request procedure and a new response procedure for transmitting information regarding low-latency STAs.

[0337] The embodiments described above are combinations of the components and features of the present disclosure in a predetermined form. Each component or feature should be considered optional unless otherwise explicitly mentioned. Each component or feature may be implemented in a form that does not combine with other components or features. It is also possible to combine some components and / or features to constitute embodiments of the present disclosure. The order of operations described in embodiments of the present disclosure may be changed. Some components or features of one embodiment may be included in other embodiments, or replaced by corresponding components or features of other embodiments. It is clear that claims that do not have an explicit reference relationship in the claims may be combined to constitute embodiments, or may be included as new claims by amendment after filing.

[0338] It will be obvious to those skilled in the art that this disclosure can be embodied in other specific forms, provided that the essential features of this disclosure are not deviated from. Therefore, the above-mentioned detailed description should not be constrained in any way and should be considered illustrative. The scope of this disclosure should be determined by a reasonable interpretation of the attached claims, and any modifications within the equivalent scope of this disclosure are included within the scope of this disclosure.

[0339] The scope of this disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that cause an apparatus or computer to perform operations according to the methods of various embodiments, and non-transitory computer-readable medium on which such software or instructions are stored and executable on the apparatus or computer. Instructions available for programming a processing system that performs the features described in this disclosure may be stored on / in a storage medium or computer-readable storage medium, and the features described in this disclosure may be embodied using a computer program product including such storage medium. The storage medium may include, but is not limited to, high-speed random-access memory such as DRAM, SRAM, DDR RAM, or other random-access solid-state memory devices, and may include non-volatile memory such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. Memory optionally includes one or more storage devices located remotely from the processor. Memory, or alternatively, non-volatile memory devices within memory, include non-transitory computer-readable storage medium. The features described in this disclosure may be stored on any one of the machine-readable media and integrated into software and / or firmware that can control the hardware of the processing system and cause the processing system to interact with other mechanisms that utilize the results relating to the embodiments of this disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems and execution environments / containers. [Industrial applicability]

[0340] Although the method proposed in this disclosure has been described primarily in the context of its application to IEEE 802.11-based systems, it can be applied to a variety of other wireless LAN or wireless communication systems.

Claims

1. The stage where a non-AP (access point) STA (station) performs the r-TWT (restricted target wake time) membership setup procedure with the AP, The non-AP STA includes the step of receiving r-TWT schedule information included in the broadcast TWT element from the AP, Based on the fact that the AP is the holder of the first TXOP (transmission opportunity), and that no portion of the first TXOP within the r-TWT SP (service period) announced by the r-TWT schedule information is used to transmit a DL frame corresponding to at least one r-TWT DL (downlink) TID (traffic identifier), or to request a UL frame corresponding to at least one r-TWT UL (uplink) TID, The first TXOP terminates before the start time of the r-TWT SP, and Within the r-TWT SP, the DL frame is received from the AP by the non-AP STA, or the UL frame is transmitted to the AP by the non-AP STA. Based on the fact that the portion of the first TXOP is used to transmit the DL frame corresponding to the at least one r-TWT DL TID, or to request the UL frame corresponding to the at least one r-TWT UL TID, the first TXOP does not terminate after the start time of the r-TWT SP. A method in which, based on the fact that the non-AP STA is the holder of the second TXOP, the second TXOP terminates before the start time of the r-TWT SP.

2. The method according to claim 1, wherein the at least one r-TWT DL TID, or the at least one r-TWT UL TID, is set by the non-AP STA and the AP.

3. The method according to claim 1, wherein the r-TWT schedule information is received from the AP by a beacon frame or a probe response frame.

4. The method according to claim 2, wherein the end time of the r-TWT SP is postponed based on the fact that the first TXOP does not end after the start time of the r-TWT SP.

5. non-AP (access point) STA (station), At least one transceiver and, The system comprises at least one processor connected to the at least one transceiver, The aforementioned at least one processor is Perform the r-TWT (restricted target wake time) membership setup procedure with the AP. The system is configured to receive r-TWT schedule information included in the broadcast TWT element from the AP via at least one transceiver. Based on the fact that the AP is the holder of the first TXOP (transmission opportunity), and that no portion of the first TXOP (transmission opportunity) within the r-TWT SP (service period) announced by the r-TWT schedule information is used to transmit a DL frame corresponding to at least one r-TWT DL (downlink) TID (traffic identifier), or to request a UL frame corresponding to at least one r-TWT UL (uplink) TID, The first TXOP terminates before the start time of the r-TWT SP, and Within the r-TWT SP, the DL frame is received from the AP by the non-AP STA, or the UL frame is transmitted to the AP by the non-AP STA. Based on the fact that the portion of the first TXOP is used to transmit the DL frame corresponding to the at least one r-TWT DL TID, or to request the UL frame corresponding to the at least one r-TWT UL TID, the first TXOP does not terminate after the start time of the r-TWT. Based on the fact that the non-AP STA is the holder of the second TXOP, the second TXOP is a non-AP STA that terminates before the start time of the r-TWT SP.

6. It is an AP (access point), At least one transceiver and, The system comprises at least one processor connected to the at least one transceiver, The aforementioned at least one processor is Perform the r-TWT (restricted target wake time) membership setup procedure with non-AP STA. The r-TWT schedule information included in the broadcast TWT element is configured to be transmitted to the non-AP STA via the at least one transceiver. Based on the fact that the AP is the holder of the first TXOP (transmission opportunity), and that no portion of the first TXOP (transmission opportunity) within the r-TWT SP (service period) announced by the r-TWT schedule information is used to transmit a DL frame corresponding to at least one r-TWT DL (downlink) TID (traffic identifier), or to request a UL frame corresponding to at least one r-TWT UL (uplink) TID, The first TXOP terminates before the start time of the r-TWT SP, and Within the r-TWT SP, the DL frame is transmitted by the AP to the non-AP STA, or the UL frame is received by the AP from the non-AP STA. Based on the fact that the portion of the first TXOP is used to transmit the DL frame corresponding to the at least one r-TWT DL TID, or to request the UL frame corresponding to the at least one r-TWT UL TID, the first TXOP does not terminate after the start time of the r-TWT. Based on the fact that the non-AP STA is the holder of the second TXOP, the second TXOP terminates before the start time of the r-TWT SP, AP.

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