Method and apparatus for sending and receiving traffic in a wireless LAN system

Abstract

A method and apparatus for operating in a wireless LAN system are disclosed. A method performed by a first station (STA) in a wireless LAN system according to one embodiment of the present disclosure includes the steps of: receiving a first physical layer protocol data unit (PPDU) from an access point (AP); transmitting a block acknowledgement (BA) frame for the first PPDU to the AP, wherein the BA frame includes low latency traffic (LLT) information; and transmitting the LLT associated with the LLT information to the AP within a transmission opportunity (TXOP), wherein the BA frame may include at least one field relating to whether or not the LLT information is included in the BA frame.

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for transmitting and receiving traffic and traffic-related information in a wireless local area network (WLAN) system.

Background Art

[0002] New technologies have been introduced for wireless local area networks (WLANs) to achieve higher transmission rates, increased bandwidth, improved reliability, reduced errors, reduced latency, and the like. Among wireless LAN technologies, the Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards may be referred to as Wi-Fi. For example, technologies recently introduced to wireless LANs include enhancements for Very High-Throughput (VHT) in the 802.11ac standard, enhancements for High Efficiency (HE) in the IEEE 802.11ax standard, and the like.

[0003] To provide an improved wireless communication environment, improvement technologies for Extremely High Throughput (EHT) are under discussion. 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) are being researched. In particular, various technologies for supporting traffic with low latency or real-time characteristics are under research. Furthermore, new technologies for supporting ultra high reliability (UHR), including improvements or extensions of EHT technologies, are under discussion.

Summary of the Invention

Problem to be Solved by the Invention

[0004] The technical issue addressed in this disclosure relates to a method and apparatus for sending and receiving traffic in a wireless LAN system.

[0005] The technical problem of this disclosure relates to a method and apparatus for transmitting information for low-latency traffic and associated preemption operations 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] An embodiment of the present disclosure, a method performed by a first station (STA) in a wireless LAN system, comprises the steps of: receiving a first physical layer protocol data unit (PPDU) from an access point (AP); transmitting a block acknowledgement (BA) frame for the first PPDU to the AP, wherein the BA frame includes low latency traffic (LLT) information; and transmitting the LLT associated with the LLT information to the AP within a transmission opportunity (TXOP), wherein the BA frame may include (may include; configure; construct; set; enclose; encompass; contain; contain; may have; may have) at least one field relating to whether or not the LLT information is included in the BA frame.

[0008] Another embodiment of the present disclosure, a method performed by an access point (AP) in a wireless LAN system, includes the steps of: receiving a physical layer protocol data unit (PPDU) from at least one STA; receiving a block acknowledgement (BA) frame for the first PPDU from the at least one STA, wherein the BA frame includes low latency traffic (LLT) information; and receiving LLT associated with the LLT information from the at least one STA within a transmission opportunity (TXOP), wherein the BA frame may include at least one field relating to whether or not the LLT information is included on the BA frame. [Effects of the Invention]

[0009] Various embodiments of this disclosure can provide methods and apparatus for sending and receiving traffic in a wireless LAN system.

[0010] Various embodiments of this disclosure provide a method and apparatus for transmitting information for low-latency traffic preemption operation in a wireless LAN system.

[0011] The effects derived from this disclosure are not limited to those mentioned above, and any other effects not mentioned above will be clearly understood by a person with ordinary skill in the art to which this disclosure pertains from the following description. [Brief explanation of the drawing]

[0012] The accompanying drawings, included as part of the detailed description to aid in understanding this disclosure, provide examples of the disclosure and illustrate the technical features of the disclosure together with the detailed description.

[0013] [Figure 1]This is a block diagram illustrating an example of a wireless communication device according to one embodiment of the present disclosure. [Figure 2] This figure shows an exemplary structure of a wireless LAN system to which this disclosure can be applied. [Figure 3] This diagram illustrates the link setup process to which this disclosure applies. [Figure 4] This diagram illustrates the backoff process to which this disclosure applies. [Figure 5] This diagram illustrates the CSMA / CA baseframe transmission operation to which this disclosure can be applied. [Figure 6] This figure illustrates an example of a frame structure used in a wireless LAN system to which this disclosure can be applied. [Figure 7] This figure shows an example of a PPDU as defined in the IEEE 802.11 standard to which this disclosure applies. [Figure 8] This figure shows an exemplary format of a trigger frame to which this disclosure can be applied. [Figure 9] This diagram illustrates the problems related to LLT transmission in DL (downlink) TXOP. [Figure 10] This diagram illustrates the problems related to LLT transmission in UL (uplink) TXOP. [Figure 11] This is a flowchart illustrating the operation of the first STA according to one embodiment of the present disclosure. [Figure 12] This is a flowchart illustrating the operation of an AP according to one embodiment of the present disclosure. [Figure 13] This is a diagram illustrating a method by which an STA reports LLT information to an AP according to one embodiment of the present disclosure. [Figure 14] This figure illustrates an LLT information transmission method using an HT control field according to one embodiment of the present disclosure. [Figure 15] This is a diagram illustrating the configuration of a BA frame containing LLT information according to one embodiment of the present disclosure. [Figure 16]FIG. 1 is a diagram for explaining a procedure of transmitting and receiving a BA frame including LLT information in an embodiment of the present disclosure. [Figure 17] FIG. 2 is a diagram for explaining a configuration of an LLT BA frame and a procedure of transmitting and receiving the LLT BA frame according to an embodiment of the present disclosure. [Figure 18] FIG. 3 is a diagram for explaining a configuration of an LLT BA frame for multi-TID and a transmission / reception procedure of LLT BA according to an embodiment of the present disclosure. [Figure 19] FIG. 4 is a diagram for explaining a configuration of an LLT BA frame for multi-TID and a transmission / reception procedure of LLT BA according to an embodiment of the present disclosure. [Figure 20] FIG. 5 is a diagram for explaining a method of transmitting LLT information using a MAC header according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF EMBODIMENTS

[0014] Hereinafter, preferred embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed below with the accompanying drawings is for describing exemplary embodiments of the present disclosure, and is not intended to show the only feasible embodiments of the present disclosure. The following detailed description includes specific details to provide a complete understanding of the present disclosure. However, it will be understood by those skilled in the art that the present disclosure can be implemented without these specific details.

[0015] In some cases, well-known structures and devices may be omitted to avoid obscuring the concept of the present disclosure, and may be shown in the form of block diagrams focusing on the core functions of each structure and device.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] The examples in this disclosure may be applied to various 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 802.11bn (or UHR) standard-based wireless LANs. In addition, the examples in this disclosure may be applied to next-generation standard-based wireless LANs following IEEE 802.11bn. 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: registered trademark: hereinafter the same) standard LTE (Long Term Evolution) series technologies and 5G NR (New Radio) series technologies.

[0020] The following describes the technical features to which the examples in this disclosure may apply.

[0021] Figure 1 is a block diagram illustrating an example of a wireless communication device according to one embodiment of the present disclosure.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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).

[0026] 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.

[0027] 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.

[0028] The hardware elements of devices 100,200 are 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., functional layers 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.

[0029] 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.

[0030] 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.

[0031] 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 send 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.

[0032] 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 / bn, 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 of Figure 1.

[0033] 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.

[0034] Figure 2 shows an exemplary structure of a wireless LAN system to which this disclosure can be applied.

[0035] 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.

[0036] 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, could be considered typical examples 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.

[0037] 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).

[0038] 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.

[0039] 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.

[0040] 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).

[0041] 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.

[0042] 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.

[0043] An Extended Service Set (ESS) may be added to the aforementioned DS structure to provide even broader coverage.

[0044] 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.

[0045] 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.

[0046] Figure 3 is a diagram illustrating the link setup process to which this disclosure can be applied.

[0047] 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.

[0048] 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.

[0049] 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).

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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) requests / responses, 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.

[0058] 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.

[0059] Figure 4 is a diagram illustrating the backoff process to which this disclosure can be applied.

[0060] 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.

[0061] 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).

[0062] 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,...).

[0063] 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.

[0064] 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.

[0065] 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. Subtypes of control frames include RTS (Request-To-Send), CTS (Clear-To-Send), ACK (Acknowledgment), PS-Poll (Power Save-Poll), Block ACK (BlockAck), Block ACK Request (BlockACKReq), NDP Announcement (null data packet announcement), and Trigger. If a control frame is not a response frame to a previous frame, it is sent after a backoff that occurs after DIFS (Distributed Ingress Fault System), and if it is a response frame to a previous frame, it is sent after a short IFS (Shorter Ingress Fault System) without a backoff. The type and subtype of a frame may be identified by the type field and subtype field in the frame control (FC) field.

[0066] 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.

[0067] Figure 5 is a diagram illustrating the CSMA / CA baseframe transmission operation to which this disclosure can be applied.

[0068] 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.

[0069] 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.

[0070] 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, STA3's carrier sensing 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, STA3's carrier sensing 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.

[0071] 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.

[0072] 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.

[0073] 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 channel access until the NAV timer expires.

[0074] When STA1 receives a CTS frame from STA2, it can send a data frame to STA2 after SIFS from the time the CTS frame reception is complete. 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 the channel is in use or not. 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] A basic PPDU 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 format shown in Figure 7) may consist only of an L-STF (Legacy-STF), an L-LTF (Legacy-LTF), an L-SIG (Legacy-SIG) field, and a Data field. Depending on the type of PPDU format (e.g., HT-mixed format PPDU, HT-greenfield format PPDU, VHT (Very High Throughput) PPDU, etc.), additional (or other types of) RL-SIG, U-SIG, non-legacy SIG fields, non-legacy STF, non-legacy LTF (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) may be included between the L-SIG field and the Data field. More specific details will be discussed later, referring to Figure 7.

[0079] 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.

[0080] The SIG field may contain various information related to PPDU transmission and reception. For example, the L-SIG field consists of 24 bits and may include a 4-bit Rate field, a 1-bit Reserved bit, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field. The RATE field may contain information about the data modulation and coding rate. 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.

[0081] 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.

[0082] A MAC PDU is defined by various MAC frame formats, and a basic MAC frame consists of a MAC header, frame body, and FCS (Frame Check Sequence). A MAC frame is composed of a MAC PDU and may be transmitted / received by a PSDU, which is the data portion of the PPDU format.

[0083] 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. The Address subfield can indicate the frame's receiver address, transmitter address, destination address, and source address, and some Address subfields may be omitted. Sequence Control, QoS Control, and HT Control subfields are also included, and the specific contents of each subfield of the MAC header can be found in the IEEE 802.11 standard document.

[0084] The null data PPDU (NDP) format refers to a form of PPDU format that does not include data fields. In other words, NDP is a frame format that includes the PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields, and if present, also non-legacy SIG, non-legacy STF, and non-legacy LTF fields) in a general PPDU format, but does not include the rest (i.e., data fields).

[0085] Figure 7 shows an example of a PPDU as defined in the IEEE 802.11 standard to which this disclosure applies.

[0086] 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 (Figure 7(a)).

[0087] 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(b) can be referred to as 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).

[0088] An example of the VHT PPDU format (IEEE 802.11ac) further includes the VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in addition to the basic PPDU format (Figure 7(c)).

[0089] 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 (Figure 7(d)). 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), but not 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. For example, RL-SIG may be configured identically to L-SIG. Based on the presence of RL-SIG, the receiving STA can determine that the received PPDU is either an HE PPDU or an EHT PPDU, as described later.

[0090] The EHT PPDU format may include the EHT MU (multi-user) format shown in Figure 7(e) and the EHT TB (trigger-based) PPDU format shown in Figure 7(f). The EHT PPDU format is similar to the HE PPDU format in that it includes an RL-SIG following the L-SIG, but it may also include a U (universal)-SIG, EHT-SIG, EHT-STF, and EHT-LTF following the RL-SIG.

[0091] The EHT MU PPDU in Figure 7(e) 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 transmission or MU transmission. For example, the EHT MU PPDU may correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0092] The EHT TB PPDU in Figure 7(f) 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 (triggered response scheduling)) can perform UL transmission based on the EHT TB PPDU format.

[0093] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal SIGNAL), and EHT-SIG fields may be encoded and modulated so that they can be attempted to be demodulated and decoded even by legacy STAs, and may be mapped based on a defined subcarrier frequency interval (e.g., 312.5 kHz). These may be referred to as pre-EHT modulated fields. Next, the EHT-STF, EHT-LTF, Data, and PE fields may be encoded and modulated so that they can be demodulated and decoded by STAs that have successfully decoded non-legacy SIGs (e.g., U-SIG and / or EHT-SIG) and obtained the information contained in those fields, and may be mapped based on a defined subcarrier frequency interval (e.g., 78.125 kHz). These may be referred to as EHT modulated fields.

[0094] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields can be referred to as pre-HE modulated fields, while the HE-STF, HE-LTF, Data, and PE fields can be referred to as HE modulated fields. Furthermore, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be referred to as pre-VHT modulated fields, while the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields can be referred to as VHT modulated fields.

[0095] The U-SIG included in the EHT PPDU format in Figure 7 may be composed of, for example, 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.

[0096] U-SIGs may be configured in 20MHz units. For example, when an 80MHz PPDU is configured, identical U-SIGs may be duplicated in 20MHz units. That is, an 80MHz PPDU may contain four identical U-SIGs. When the bandwidth exceeds 80MHz, for example, for a 160MHz PPDU, the first 80MHz U-SIG and the second 80MHz U-SIG may be different from each other.

[0097] In a U-SIG, for example, A uncoded bits may be transmitted, and the first U-SIG symbol (e.g., U-SIG-1 symbol) may transmit the first X bits of the total A bits, while the second U-SIG symbol (e.g., U-SIG-2 symbol) may transmit the remaining Y bits of the total A bits. The A bits (e.g., 52 uncoded bits) may include a CRC field (e.g., a 4-bit field) and a tail field (e.g., a 6-bit field). The tail field may be used to terminate the trellis of the convolution decoder and may be set to 0, for example.

[0098] The A bit information transmitted by U-SIG can be distinguished into version-independent bits and version-dependent bits. For example, a new PPDU format not shown in Figure 7 (e.g., UHR PPDU format) may include U-SIG, and the format of the U-SIG field in the EHT PPDU format and the format of the U-SIG field in the UHR PPDU format may be the same, while the version-independent bits may differ in some or all respects.

[0099] For example, the size of the version-independent bits of a U-SIG may be fixed or variable. The version-independent bits may be assigned only to U-SIG-1 symbols, or to both U-SIG-1 and U-SIG-2 symbols. Version-independent and version-dependent bits may be referred to by various names, such as the first control bit and the second control bit.

[0100] For example, the version-independent bits of the U-SIG may include a 3-bit physical layer version identifier (PHY version identifier), which can indicate the PHY version of the transmitted and received PPDUs (e.g., EHT, UHR, etc.). The version-independent bits of the U-SIG may include a 1-bit UL / DL flag field. The first value of the 1-bit UL / DL flag field relates to UL communication, and the second value relates to DL communication. The version-independent bits of the U-SIG may also include information about the length of the TXOP (transmission opportunity) and information about the BSS color ID.

[0101] For example, the version-dependent bits of the U-SIG may include information that directly or indirectly indicates the type of PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).

[0102] The U-SIG may include information necessary for transmitting and receiving PPDUs. For example, the U-SIG may further include information about bandwidth, information about the MCS technique applied to non-legacy SIGs (e.g., EHT-SIG or UHR-SIG), information indicating whether a dual carrier modulation (DCM) technique (e.g., a technique for reusing the same signal on two subcarriers to achieve an effect similar to frequency diversity) is applied to the non-legacy SIG, information about the number of symbols used for the non-legacy SIG, and information about whether the non-legacy SIG is generated across the entire bandwidth.

[0103] Some of the information necessary for sending and receiving PPDUs may be included in the U-SIG and / or non-legacy SIGs (e.g., EHT-SIG or UHR-SIG). For example, information regarding the type of non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF), information regarding the length and cyclic prefix (CP) length of non-legacy LTFs, information regarding the guard interval (GI) applicable to non-legacy LTFs, information regarding preamble puncturing applicable to PPDUs, and information regarding resource unit (RU) allocation may be included only in the U-SIG, only in the non-legacy SIG, or indicated by a combination of information included in the U-SIG and information included in the non-legacy SIG.

[0104] Preamble puncturing can mean the transmission of a PPDU in which one or more frequency units within the PPDU's bandwidth are not present. For example, the size of the frequency units (or the resolution of preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to PPDU bandwidths of a certain size or larger.

[0105] In the example shown in Figure 7, non-legacy SIGs such as HE-SIG-B and EHT-SIG may contain control information for the receiving STA. Non-legacy SIGs 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 a previous SIG (e.g., HE-SIG-A, U-SIG, etc.).

[0106] Non-legacy SIGs such as HE-SIG-B and EHT-SIG may include common fields and user-specific fields. Common fields and user-specific fields may be coded separately.

[0107] In some cases, the common field may be omitted. For example, in a compressed mode where non-OFDMA (orthogonal frequency multiple access) is applied, the common field may be omitted, and multiple STAs can receive PPDUs (e.g., the data fields of the PPDU) in the same frequency band. In an uncompressed mode where OFDMA is applied, multiple users can receive PPDUs (e.g., the data fields of the PPDU) in separate frequency bands.

[0108] The number of user-specific fields may be determined based on the number of users. A single user block field may contain a maximum of two user fields. Each user field may be associated with either MU-MIMO or non-MU-MIMO assignments.

[0109] The common field 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. The common field may include RU allocation information. The RU allocation information may include information about the location of RUs to which multiple users (i.e., multiple receiving STAs) are assigned.

[0110] A RU may contain multiple subcarriers (or tones). RUs may be used when transmitting signals to multiple STAs based on the OFDMA method. Alternatively, a RU may be defined when transmitting a signal to a single STA. Resources may be allocated on a RU basis for non-legacy STFs, non-legacy LTFs, and Data fields.

[0111] The applicable size of RUs may be defined by the PPDU bandwidth. RUs may be defined to be identical or different for the applicable PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, for an 80MHz PPDU, the RU arrangement for HE PPDU and EHT PPDU may differ from each other. The applicable RU size, number of RUs, RU locations, DC (direct current) subcarrier locations and number, null subcarrier locations and number, guard subcarrier locations and number, etc., for each PPDU bandwidth can be called a tone plan. For example, a tone plan for a wide bandwidth may be defined as multiple iterations of a low-bandwidth tone plan.

[0112] RUs of various sizes may be defined as 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs, 996-tone RUs, 2×996-tone RUs, 4×996-tone RUs, etc. An MRU (multiple RU) is distinct from multiple individual RUs and corresponds to a group of subcarriers composed of multiple RUs. For example, one MRU may be defined as 52+26 tones, 106+26 tones, 484+242 tones, 996+484 tones, 996+484+242 tones, 2×996+484 tones, 3×996 tones, or 3×996+484 tones. Furthermore, the multiple RUs that make up a single MRU may or may not be consecutive in the frequency domain.

[0113] The specific size of a RU may be reduced or expanded. Therefore, the specific size of each RU (i.e., the number of corresponding tones) in this disclosure is illustrative and not restrictive. Also, in this disclosure, the number of RUs within a given bandwidth (e.g., 20, 40, 80, 160, 320 MHz, ...) may vary depending on the size of the RU.

[0114] In the PPDU format shown in Figure 7, the names of the fields are illustrative and do not limit the scope of this disclosure. Furthermore, the examples in this disclosure may apply not only to the PPDU format illustrated in Figure 7, but also to new PPDU formats that are based on the PPDU format in Figure 7 but with some fields excluded and / or some fields added.

[0115] Figure 8 shows an exemplary format of a trigger frame to which this disclosure may apply.

[0116] A trigger frame can allocate resources for one or more TB PPDU transmissions and request TB PPDU transmissions. The trigger frame may also include other information requested by the STA that will transmit TB PPDUs in response. The trigger frame may include common info and user info list fields in its frame body.

[0117] The common information field may include information that applies in common to one or more TB PPDU transmissions requested by a trigger frame, such as the trigger type, UL length, whether or not there is a subsequent trigger frame (e.g., More TF), whether or not a CS (channel sensing) request is made, and UL BW (bandwidth). Figure 8 illustrates the common information field format for an EHT variant.

[0118] A 4-bit trigger type subfield may have values ​​from 0 to 15. Of these, values ​​0, 1, 2, 3, 4, 5, 6, and 7 of the trigger type subfield are defined to correspond to basic, BFRP (Beamforming Report Poll), MU-BAR (multi user-block acknowledgement request), MU-RTS (multi user-request to send), BSRP (Buffer Status Report Poll), GCR (groupcast with retries) MU-BAR, BQRP (Bandwidth Query Report Poll), and NFRP (NDP Feedback Report Poll), respectively, while values ​​from 8 to 15 are defined as reserved.

[0119] Among the common information, the trigger-dependent common info subfield may include information that is selectively included based on the trigger type.

[0120] A special user info field may be included within the trigger frame. The special user info field does not contain user-specific information, but it does contain extended common information not provided in the common information field.

[0121] The user information list contains zero or more user info fields. Figure 8 illustrates the EHT variant user info field format.

[0122] The AID12 subfield essentially indicates that it is a user information field for the STA having that AID. Additionally, if the AID12 field has a predetermined specific value, it may be used for other purposes, such as assigning a Random Access (RA)-RU or being configured as a special user info field. A special user info field is a user information field that does not contain user-specific information but includes extended common information not provided in the common information field. For example, a special user info field may be identified by the AID12 value 2007, and a special user info field flag subfield within the common information field may indicate whether or not it contains a special user info field.

[0123] The RU allocation subfield can indicate the size and location of the RU / MRU. To this end, the RU allocation subfield may be analyzed together with the PS160 (primary / secondary 160MHz) subfield of the user information field, the UL BW subfield of the common information field, and so on.

[0124] HT control field

[0125] The following section provides a more detailed explanation of the HT control field included in the MAC header, as described in Figure 6.

[0126] The HT control field may be present in the control wrapper frame, the QoS data determined by the +HTC subfield of the frame control field, QoS Null, and the management frame.

[0127] An STA supporting an HT control field that receives a control wrapper frame can process it as if it had received a frame of the wrapper frame subtype. The HE STA does not need to send the control wrapper frame to other HE STAs.

[0128] The HT control field may have the format shown in Table 1 below.

[0129] [Table 1]

[0130] As disclosed in Table 1, the HT control field may include three variants (e.g., HT variant, VHT variant, and HE variant). The variant format may be distinguished by the values ​​of the first bit (B0) and the second bit (B1) of the HT control field.

[0131] The HT variant's HT control field may include an HT control middle subfield, and the VHT variant's HT control field may include a VHT control middle subfield. The VHT control middle subfield may include an MRQ subfield, an MSI / STBC subfield, an MFSI / GID-L subfield, an MFB subfield, a GID-H subfield, a coding type subfield, an FB Tx type subfield, and an unsolicited MFB subfield.

[0132] The HE variant HT control field may include an A (aggregated)-control subfield. The A-control subfield may include a variable-length control list subfield and zero or more padding subfields. The control list may include one or more control subfields. One control subfield may include a 4-bit control ID subfield and a variable-length control information subfield.

[0133] The control ID subfield can indicate the type of information transmitted in the control information subfield. The length of the control information subfield may be fixed for each unreserved value in the control ID subfield. The association length between the values ​​of the control ID subfield and the control information subfield may be defined as shown in Table 2 below.

[0134] [Table 2]

[0135] Information corresponding to control ID values ​​0 to 6 may be defined in the A-control subfield of the HE variant HT control field. Information corresponding to control ID values ​​7 to 9 may be newly defined information for EHT STA. Also, information corresponding to control ID value 10 (i.e., AAR) may correspond to control 1D value 9. Furthermore, if a padding subfield exists in the A-control subfield of the HE variant HT control field, the padding subfield may follow the last control subfield and be set to a sequence of zeros such that the length of the A-control subfield transmitted in the HT control field is 30 bits.

[0136] Information transmission procedure for low-latency traffic preemption

[0137] In a basic wireless LAN system, an STA (e.g., a non-AP STA and / or AP) can perform channel access operations to transmit a frame containing traffic. For example, an AP and / or a non-AP STA can acquire a transmission opportunity (TXOP) through EDCA (Enhanced Distributed Channel Access) and transmit a frame within the acquired TXOP. As another example, a non-AP STA can transmit a frame as a response to a trigger frame received from an AP.

[0138] In other words, when specific traffic enters / originates in an STA's transmit queue, the STA must access the channel to transmit that traffic, thereby occupying the channel and / or obtaining a TXOP. Now, let's assume that traffic requiring extremely low latency (i.e., low-latency traffic) enters / originates in the STA's transmit queue. Contention for channel access with other STAs is unavoidable for that STA to transmit the low-latency traffic, and if another STA has already obtained a TXOP, there is a problem in that the rapid transmission of the low-latency traffic cannot be guaranteed.

[0139] In this disclosure, traffic requiring low latency (for example, traffic that should be successfully transmitted within X ms) will be referred to as LLT (low latency traffic).

[0140] Figure 9 illustrates the problems related to LLT transmission in DL (downlink)TXOP.

[0141] Specifically, as shown in Figure 9, when an AP (i.e., a TXOP holder) acquires a DL TXOP through channel access and then exchanges frames with STA1 (i.e., a TXOP responder), the LLT to be sent to the AP may arrive at STA2 at time T_1. STA2 may then set NAV based on the AP's TXOP, or determine the channel status to be busy based on the frame exchange between the AP and STA1.

[0142] Therefore, STA2 can perform another backoff process after AP's TXOP and transmit LLT. However, if AP's TXOP is long, and STA2 performs a backoff after AP's TXOP, there is a possibility that another STA may acquire the TXOP due to the result of a conflict. Therefore, STA2's LLT transmission may be significantly delayed, and there is a possibility that the LLT requirements may not be met.

[0143] Figure 10 is a diagram illustrating the problems related to LLT transmission in UL (uplink)TXOP.

[0144] Specifically, as shown in Figure 10, when STA1 (i.e., the TXOP holder) acquires a (UL)TXOP through channel access and then exchanges frames with AP (i.e., the TXOP responder), the LLT to be sent to STA2 may arrive at AP at time T_1. AP is not exchanging frames within STA1's TXOP and therefore cannot send the LLT to STA2. For this reason, AP can perform another backoff process after STA1's TXOP before sending the LLT to STA2.

[0145] In this case, STA1's TXOP may be long, and when the AP performs a backoff after STA1's TXOP, there is a possibility that another STA may acquire the TXOP due to the competition. As a result, the AP's LLT transmission may be significantly delayed, and there is a possibility that the LLT requirements may not be met.

[0146] As illustrated with reference to Figures 9 and 10, when an LLT (i.e., an LLT with transmission-related requirements) arrives that should be transmitted quickly by one STA, there is a possibility that the STA may transmit the LLT without fulfilling the requirements due to factors such as the TXOP length already acquired by another STA or channel access delays due to competition with other STAs. This disclosure describes a method for resolving the above-mentioned problems.

[0147] The names of the procedures and / or parameters described herein may be changed, and STA may include non-AP STA or AP STA. Furthermore, in describing this disclosure, RU (resource unit) may mean RU or M (multiple)RU.

[0148] Figure 11 is a flowchart illustrating the operation of the first STA according to one embodiment of the present disclosure. In Figures 11 and 12, the first STA and the second STA may be embodied as a non-AP STA or an AP, and the AP may be replaced by another non-AP STA.

[0149] The first STA can receive the first physical layer protocol data unit from the access point (AP) (S1110).

[0150] In this case, the first STA can receive a PPDU from the AP within the TXOP acquired by the AP. That is, the AP may be a TXOP holder, and the first STA may be a TXOP responder. However, this is only one embodiment, and the first STA may be one of the non-AP STAs associated with an AP that is not a TXOP responder, and the second STA may be a TXOP responder. In this case, the second STA can also perform the same operation as the first STA, which will be described later.

[0151] For example, the first PPDU may include an A-MPDU containing QoS data frames for one or more TIDs. Additionally or alternatively, the first PPDU may include information to trigger the transmission of LLT information (e.g., a frame that triggers LLT information).

[0152] On the other hand, the first STA may have an LLT generated / existing before and / or after receiving the first PPDU. That is, the first STA may have an LLT generated or existing for transmission before and / or after receiving the first PPDU. The first STA can generate LLT information related to the LLT.

[0153] Here, the LLT information may include at least one of the following: LLT identification information, information about the time at which the LLT should be completed, and information about the amount of LLT.

[0154] The first STA can send a block acknowledgment (BA) frame to the first PPDU to the AP (S1120). Here, the BA frame may contain low-latency traffic (LLT) information.

[0155] Specifically, a BA frame may include at least one field related to whether or not LLT information is included in the BA frame. For example, at least one field may include an AID (association identification) field, an ACK type field, and a TID (traffic identifier) ​​field.

[0156] For example, based on the AID 11 field value being set as the first value, the ACK type field value being set as the second value, and the TID field value being set as the third value, the combination of the AID 11 field, ACK type field, and TID field may indicate that LLT information is included in the BA frame (or that LLT information exists following the AID 11 field, ACK type field, and TID field). In this case, {first value, second value, third value} may be, but is not limited to, {2020,0,0} or {0,0,8}.

[0157] As an addition or alternative, the BA information field of the BA frame may include a Per AID TID Info field for LLT, where the Per AID TID Info field may include at least one field (e.g., an AID 11 field, an ACK type field, and a TID field) and a fragment number field.

[0158] As an example, let's assume that the AID 11 field value is set as the first value, the ACK type field value is set as the second value, and the TID field value is set as the third value. In this case, the fragment number field may indicate the length of the LLT information (i.e., the length of the field indicating the LLT information), or the total length of the specific field containing the LLT information. That is, LLT information may be set in a portion of the specific field. In this case, the field indicating the LLT information may be placed on the BA frame following the fragment number field. For example, the LLT information may be placed immediately after the fragment field (i.e., adjacent to the fragment field), but is not limited to this. The LLT information may be placed after the fragment field, but does not have to be adjacent.

[0159] As an addition or alternative, the BA information may include ACK information for at least one QoS data contained in the first PPDU. That is, the first STA can send ACK information for the first PPDU (i.e., the data frame contained in the first PPDU) to the AP along with the LLT information.

[0160] However, this is only one embodiment, and the first STA can transmit LLT information to the AP not only through the BA frame but also through the HT control field and / or the MAC header.

[0161] When describing this disclosure, the name of the field indicating the length of the LLT information (i.e., the length of the field indicating the LLT information) or the total length of a particular field containing the LLT information may be changed in various ways, not just the fragment number field. Also, the name and number of at least one field related to whether or not the LLT information is included on the BA frame may be changed in various ways.

[0162] For example, based on the PER AID TID Info field indicating the presence of LLT information on the BA frame, the names of fields associated with the LLT information (e.g., fragment fields, at least one of the fields mentioned above) may be changed.

[0163] The first STA can transmit LLT information and associated LLT to the AP within TXOP (S1130).

[0164] As an example of this disclosure, the first STA can receive a trigger frame (for example, a trigger frame for LLT transmission) from the AP after transmitting LLT information. The first STA can transmit the LLT to the AP based on the trigger frame. However, this is only one embodiment, and the first STA can also transmit LLT information and then transmit the LLT to the AP after a predetermined time.

[0165] The example described above illustrates the procedure in which the first STA sends LLT information and then sends the LLT, but is not limited to this. The first STA can also send the LLT to the AP immediately after receiving the first PPDU.

[0166] The method described in the example in Figure 11 may be performed by the first device 100 in Figure 1. For example, one or more processors 102 of the first device 100 in Figure 1 can receive the first PPDU from the AP via one or more transceivers 106. One or more processors 102 can transmit a BA frame for the first PPDU to the AP via one or more transceivers 106.

[0167] Furthermore, one or more memories 104 of the first device 100 can store instructions for performing the method described in the example in Figure 11 or in the examples described later, when executed by one or more processors 102.

[0168] Figure 12 is a flowchart illustrating the operation of AP according to one embodiment of the present disclosure.

[0169] The AP can send a first PPDU to at least one STA (S1210). For example, the AP can obtain a TXOP by exchanging RTS and CTS frames with at least one STA (e.g., the first STA and / or the second STA). The AP can then send a first PPDU to at least one STA. For example, the first PPDU may include information that triggers the transmission of a QoS data frame (e.g., a QoS data frame for at least one TID) and / or LLT information.

[0170] The AP can receive a BA frame for the first PPDU from at least one STA (S1220). Here, the BA frame may include at least one field related to whether or not LLT information is included in the BA frame. The structure of the BA frame has been explained with reference to Figure 11, so a redundant explanation will be omitted.

[0171] The AP can determine whether LLT transmission or reception has occurred and / or information related to LLT from the LLT information contained in the BA frame. If at least one STA has LLT, the AP can send a trigger frame to at least one STA.

[0172] The AP can receive LLT information and associated LLTs from at least one STA within the TXOP (S1230).

[0173] The method described in the example in Figure 12 may be performed by the second device 200 in Figure 1. For example, one or more processors 202 of the second device 200 in Figure 1 can transmit a first PPDU to at least one STA via one or more transceivers 206. One or more processors 202 can receive a BA frame for the first PPDU from at least one STA via one or more transceivers 206. One or more processors 202 can receive LLT information and associated LLT within a TXOP from at least one STA via one or more transceivers 206.

[0174] Furthermore, one or more memories 204 of the second device 200 can store instructions for performing the method described in the example in Figure 12 or in the examples described later, when executed by one or more processors 202.

[0175] The following section specifically describes methods for transmitting information for low-latency traffic preemption.

[0176] Example 1

[0177] Example 1 relates to a procedure for reporting LLT information.

[0178] Figure 13 illustrates a method by which an STA reports LLT information to an AP according to one embodiment of the present disclosure. In Figure 13, "LLT TX Needed" means that there is / are LLT that the STA should promptly send. For example, "LLT TX Needed" can mean that there is LLT that has been input / arrived at the STA or that there is LLT that should be promptly sent to meet the requirements.

[0179] Here, the actions of AP and STA in Figure 13 may be replaced with the actions of STA and AP respectively. That is, the action of AP in Figure 12 may be replaced with the action of another STA, and the action of STA in Figure 13 may be replaced with the action of AP.

[0180] As shown in Figure 13, the AP can send trigger information to one or more STAs so that LLT information can be transmitted in the PPDU. That is, the PPDU may include a trigger frame to request / trigger the transmission of LLT information. Furthermore, the PPDU may include frames addressed to one or more STAs (e.g., QoS data frames).

[0181] An STA that receives a PPDU / frame that triggers LLT information can send a frame / PPDU containing LLT information. A predefined time interval (e.g., SIFS, PIFS) may exist between the PPDU / frame that triggers the LLT information and the frame containing the LLT information.

[0182] An AP that receives LLT information from one or more STAs can send a frame (e.g., a trigger frame) that enables one or more STAs to send LLT. One or more STAs that receive this frame can then send a frame / PPDU containing LLT to the AP.

[0183] As an addition or alternative, one or more STAs can transmit LLT information to the AP even without receiving a PPDU / frame that triggers the LLT information. For example, in Figure 13, the LLT information may be included in a frame / PPDU containing LLT transmitted by one STSA.

[0184] Example 1-1

[0185] Example 1-1 relates to one or more types of information included in the LLT information transmitted by STA.

[0186] LLT information may include LLT presence information, LLT identification information, delay information, and / or LLT amount information.

[0187] For example, LLT existence information can indicate that an LLT exists that an STA should currently transmit. Additionally or alternatively, LLT existence information can indicate within a particular STA's TXOP whether that STA requests / desires LLT transmission.

[0188] LLT existence information may be supported by a field having 1 bit (e.g., an LLT existence field). For example, if the LLT existence field value is set to 1 (or 0), this may indicate that there is an LLT that the STA should currently transmit, or that the STA requests / desires LLT transmission within a particular STA's TXOP. For example, if the LLT existence field value is set to 0 (or 1) or the field is reserved, this may indicate that there is no LLT that the STA should currently transmit, or that the STA does not request / desire LLT transmission within a particular STA's TXOP.

[0189] As still another example, the LLT identification information may include one or more pieces of ID information for an LLT to be transmitted. That is, the LLT identification information may include information related to an LLT that needs to be transmitted. As an example, a TID (traffic identifier) can be utilized as the LLT identification information. When an LLT corresponds to at least one of TIDs 0 to 7, the field indicating the LLT identification information may be set to 3 bits, and when the LLT corresponds to at least one of TIDs 8 to 15, the field indicating the LLT identification information may be set to 4 bits.

[0190] As still another example of the present disclosure, a new LLT ID for indicating identification information of an LLT may be defined. For example, the LLT ID may be defined as an ID for classifying an LLT for each TID. For example, an LLT may be classified into a 2-tuple <TID, LL ID>. For example, when LL IDs 0 to 3 are allocated to TID 6, LL traffic corresponding to TID 6 may be classified into <TID 6, LL ID 0>.

[0191] Additionally or alternatively, a bitmap may be defined for receiving an LLT corresponding to one or more IDs. That is, the LLT identification information may be configured as a bitmap indicating an LLT ID. As an example, when a total of X LLT IDs are defined, the bitmap may be configured to be capable of indicating up to X LLT IDs.

[0192] As an example, the delay information may include information related to by which time point the LLT should be transmitted.

[0193] As an example, the delay information may include, based on a time point at which LLT information is transmitted or a time point at which transmission is completed, a length of time from the base time point to the time point by which transmission of the LLT should be successfully completed. In this case, the delay information can indicate the time in units of μs.

[0194] As an addition or alternative, delay information can indicate the point at which the LLT should have successfully completed its transmission. For example, delay information can indicate the point at which the LLT should have successfully completed its transmission based on an absolute time, such as a TSF (time stamp).

[0195] As an additional or alternative, assume that there are LLTs for one or more IDs. That is, if there are LLTs for each of multiple IDs, the ID that should complete transmission earlier among the multiple IDs will be identified, and the delay information may include the time when that ID should complete transmission.

[0196] Additionally, or as an alternative, if LLT exists for each of multiple IDs, the delay information may include all the points in time when each of the multiple IDs should have completed transmission.

[0197] For example, LLT quantity information may include information about the amount of LLT that needs to be transmitted now. For example, LLT quantity information may be composed of bytes.

[0198] In addition or as an alternative, if LLT exists for one or more IDs, the LLT quantity information can indicate the total LLT quantity for all IDs. For example, the LLT quantity information may be the sum of the LLT quantities for each of all IDs.

[0199] In addition or as an alternative, if LLT exists for one or more IDs, the LLT quantity information can indicate the amount of LLT for each ID.

[0200] As an addition or alternative, let's assume that TIDs are used for LLT. In this case, the quantity information for LLT can indicate the quantity of LLT for each of the ACs (access category) to which the TID belongs. For example, if TID X and TID Y belong to AC 1, the quantity information for LLT can indicate the sum of the LLT quantities of TID X and TID Y as the quantity of LLT for AC1.

[0201] Examples 1-2

[0202] Examples 1-2 describe a method for indicating / signaling LLT information. Specifically, LLT information may be indicated / signaled in the HT control field (Example 1-2-1), the BA (black ack) frame (Example 1-2-2), and the MAC header (Example 1-2-3).

[0203] Example 1-2-1

[0204] In one embodiment of the present disclosure, LLT information may be transmitted and received in an HT control field (e.g., an A-control field). For example, the LLT information may be contained in a field defined as a new control type in the A-control field. The present disclosure refers to a control field for transmitting and receiving LLT information as an LLT information control field.

[0205] Figure 14 illustrates an LLT information transmission method using an HT control field (e.g., A-control LLT information control) according to one embodiment of the present disclosure. As shown in Figure 14, the AP can first obtain a TXOP by exchanging RTS / CTS and then transmit a PPDU to the STA1. In this example, an A(aggregated)-MPDU containing a QoS data frame on the PPDU may be transmitted to the STA1.

[0206] The PPDU may contain information that triggers STA1 to transmit LLT information. Upon receiving the PPDU, STA1 can use the A-MPDU to respond to / transmit an LLT information control field containing the LLT information to the AP. The LLT information control field may be included in at least one of the following: a BA frame, an additional QoS data frame, or a QoS null frame, and sent in response to / transmitted to the AP.

[0207] For example, if the BA frame contains an HT control field, the HT control field (or the BA frame) may be defined as a new control frame type, or the +HTC field value in the MAC header may be set to 1. Therefore, STA1 can use the BA frame to send LLT information to the AP simultaneously with ACK information for the data frame.

[0208] For example, if the PPDU sent by the AP has an ACK policy that requires an immediate response to the MPDU for a BA frame (e.g., implicit BAR), then a BA frame (or BA information) may be present on the A-MPDU sent by STA1. As another example, if the PPDU sent by the AP has an ACK policy that does not require an immediate response to the MPDU for a BA frame (e.g., ACK policy=BA), then a BA frame (or BA information) may not be present on the A-MPDU sent by STA1.

[0209] When an AP receives a PPDU / frame containing LLT information from STA1, it can enable STA1 to transmit LLT by sending a trigger frame to STA1. At this time, STA1 can include the LLT information in the response frame to the trigger frame (e.g., A-MPDU). As an example of this disclosure, STA1 can transmit LLT information to the AP together using a BA frame and / or a data frame.

[0210] Example 1-2-2

[0211] As one embodiment of this disclosure, assume that LLT information is triggered at the same time that a (QoS) data frame is transmitted to a specific STA. If LLT exists on the specific STA, the specific STA can transmit the LLT information to the AP along with the BA frame. That is, instead of the LLT information being included in other frames, the specific STA can include the LLT information in the BA frame.

[0212] Figure 15 is an example of this disclosure and illustrates the configuration of a BA frame including LLT information.

[0213] As shown in Figures 15(a) and (b), LLT information may be set / indicated in the reserved fields of the BA control field regardless of the BA type of the BA frame. As another example, LLT information may be set on the 10th bit (B9) (i.e., no memory kept), the 11th bit (B10) (i.e., memory set on tag), and the 12th bit (B11) (i.e., management ACK) of the BA control field.

[0214] As an example, as shown in Figure 15(a), the LLT existence field may be set on the first bit (B0) of the BA control field.

[0215] As yet another example, as shown in Figure 15(b), the LLT presence field may be set on the first bit (B0) of the BA control field, and LLT identification information may be set on at least one of the sixth bit (B5) to the ninth bit (B10) of the BA control field. In this case, the LLT identification information may include the TID for the LLT that needs to be transmitted, and the TID_INFO field may include information about which TID the BA frame is sent to (i.e., information that acknowledges the success or failure of one or more MPDUs for a given TID).

[0216] Figure 16 is an embodiment of the present disclosure and illustrates a procedure for sending and receiving a BA frame containing LLT information.

[0217] The AP can first obtain a TXOP through CTS / RTS exchange, and then send a PPDU to STA1. For example, this PPDU may include an A-MPDU containing a QoS data frame. In response to this PPDU, STA1 can send a BA frame containing LLT information to the AP.

[0218] The BA frame may include BA information for ACKing the QoS data frame contained in the A-MPDU. Additionally, LLT information may be included in the BA control field of the BA frame. For example, as shown in Figure 15, LLT information may be included in the BA control field. Therefore, STA1 can use the BA frame to transmit both ACK information and LLT information for the data frame to the AP.

[0219] An AP that receives a BA frame containing LLT information from STA1 can send a trigger frame to STA1. Based on the trigger frame, STA1 can send LLT to the AP. In this disclosure, LLT information may be included in the BA frame regardless of the BA type.

[0220] As an addition or alternative, a new type of BA frame may be defined, or an existing type of BA frame may be utilized, to include LLT information. In this disclosure, a BA frame defined for transmitting LLT information is referred to as an LLT BA frame.

[0221] An LLT BA frame may further include an LLT information field in addition to the basic BA frame (for example, a frame containing ACK information for a data frame). The LLT information field means a field containing one or more types of LLT information as described above.

[0222] An LLT BA frame can satisfy at least one of the conditions described below.

[0223] - A BA frame (or BA control field) and its associated BA type may be defined as a new type.

[0224] - The BA type in the BA control field may be a compressed BA frame variant.

[0225] - The BA information field of the LLT BA frame may be identical to the BA information field of the compressed BA frame variant.

[0226] - If the BA type of the LLT BA frame is a new type, the LLT information field may be located after the BA information field.

[0227] As an addition or alternative, the LLT information field can utilize the Block ACK Starting Sequence Control subfield of the BA information field in at least one of the methods described below.

[0228] - The fragment number subfield of the block ACK start sequence control subfield may be set to a specific value. If the fragment number subfield value is set to 4 bits (B3B2B1B0), the fragment number subfield value of the block ACK start sequence control subfield may be set to "1111".

[0229] As an example, as described above, an LLT information field may be contained / placed on the BA frame by a fragment number subfield with a specific value set. For example, an LLT information field may be placed following a fragment number subfield with a specific value set. Additionally or alternatively, a start sequence control subfield and / or block ACK bitmap subfield may be omitted by a fragment number subfield with a specific value set.

[0230] Figure 17 is a diagram illustrating the configuration of an LLT BA frame and the procedure for sending and receiving an LLT BA frame according to one embodiment of the present disclosure.

[0231] The AP can first obtain a TXOP through CTS / RTS exchange, and then send a PPDU to STA1. For example, the PPDU may include an A-MPDU containing a QoS data frame. The PPDU may also contain information that STA1 uses to trigger LLT information. In response to the PPDU, STA1 can send a BA frame containing LLT information (i.e., an LLT BA frame) to the AP.

[0232] As shown in Figure 17, the LLT BA frame may contain ACK information for the QoS data frame included in the A-MPDU, and the ACK information may be included in the BA information field. Additionally, a fragment number field set to a specific value may exist on the LLT BA frame to indicate the presence of LLT information. In this case, the fragment number field may, but is not limited to, be placed following the BA information field containing the ACK information.

[0233] A fragment number field set to a specific value can indicate the presence of LLT information after the fragment number field. Therefore, STA1 can use an LLT BA frame to send LLT information to the AP simultaneously with ACK information for the data frame.

[0234] An AP that receives an LLT BA frame containing LLT information from STA1 can send a trigger frame to STA1. Based on the trigger frame, STA1 can send the LLT to the AP. In various embodiments of this disclosure, the LLT information may be included on the BA frame. For example, the BA frame may contain LLT information equal to or greater than the length of the BA information field.

[0235] As one embodiment of the present disclosure, an LLT BA frame can satisfy at least one of the conditions described below if it includes information related to multiple TIDs.

[0236] - The BA type in the BA control field may be defined as a new type.

[0237] - The BA type in the BA control field may be a multi-STA BA variant.

[0238] - The BA information field of an LLT BA frame is the same as the BA information field of a multi-STA BA frame, but the format of the AID TID separate information subfield for LLT in an LLT BA frame may be different from each other.

[0239] Specifically, the AID TID information field in the AID TID-specific information subfield of the LLT BA frame may be subject to at least one of the items described below.

[0240] - When a non-AP STA transmits an LLT BA frame, the AID 11 subfield value of the AID TID-specific information subfield (for LLT) may be set to 0 or a specific value. For example, when a non-AP STA transmits an LLT BA frame to an AP, the AID 11 subfield value may be set to a value other than 0 (e.g., 1 or 2008). In addition or alternatively, in this case, the ACK type subfield and TID subfield of the AID TID-specific information subfield for LLT may be set to any value. Since a non-AP STA transmits multi-STA BA frames only to an AP, the AP can determine from the specific AID value whether or not the LLT information field exists.

[0241] - When an AP sends a PPDU to one STA, the AID 11 subfield value of the AID TID-specific information subfield (for LLT) may be set to the 11LSB of the AID of that STA. Additionally or alternatively, when an AP sends a PPDU to one or more non-AP STAs, the AID 11 subfield value of the AID TID-specific information subfield (for LLT) may be set to a specific value (e.g., 0 or one of the values ​​between 2008 and 2044).

[0242] - The ACK type subfield of the AID TID-specific information subfield (for LLT) may be set to a specific value (e.g., 0 or 1).

[0243] - The TID subfield of the AID TID-specific information subfield (for LLT) may be set to a specific value (e.g., one of 8 to 15). However, this excludes cases where the ACK type subfield value is set to 1 and the TID subfield value is set to 15.

[0244] - An LLT information field may be present following an AID 11 subfield, an ACK type subfield, and a TID subfield that satisfy the above conditions. For example, if an AID TID information field that satisfies the above conditions exists (for example, an AID TID information field containing an AID 11 subfield, an ACK type subfield, and a TID subfield), an LLT information field may be present on the AID TID-specific information subfield (for LLT).

[0245] - In addition or alternatively, if there is an AID TID information field that satisfies the above conditions (for example, an AID TID information field that includes an AID 11 subfield, an ACK type subfield, and a TID subfield), the block ACK start sequence control field and / or block ACK bitmap field does not need to be present on the LLT BA frame.

[0246] Additionally or as an alternative, if a specific value is set for the AID TID information field to satisfy the above conditions, an LLT information field may be present or included (on the LLT BA frame) instead of the block ACK start sequence control field and the block ACK bitmap field.

[0247] Additionally or alternatively, if a specific value is set for the AID TID information field to satisfy the above conditions, an LLT information field may be included instead of the block ACK start sequence control field and the block ACK bitmap field. Additionally or alternatively, the size of the LLT information field may be the length of the LLT information itself. Additionally or alternatively, the length of the block ACK start sequence control field and / or the length of the block ACK bitmap field may be included in the LLT information field.

[0248] Figure 18 is an embodiment of the present disclosure illustrating the configuration of an LLT BA frame for multi-TID and the procedure for transmitting and receiving LLT BAs.

[0249] The AP can first obtain a TXOP through CTS / RTS exchange and then send a PPDU to STA1. In this example, the PPDU may include a multi-TID A-MPDU containing QoS data frames for TID1 and TID2, respectively. The PPDU may also include information to trigger STA1's LLT information transmission.

[0250] Upon receiving the PPDU, STA1 can respond to the AP with an LLT BA frame (i.e., a multi-STA BA frame containing LLT information or a new type of LLT BA frame). As shown in Figure 18, the LLT BA frame may include a Per AID TID info subfield for ACK information for the QoS data frames contained in the A-MPDU (i.e., QoS data frames for TID1 and TID2).

[0251] Additionally, the AID TID-specific information subfield containing LLT information can use a specific ACK type (e.g., 0) and TID (e.g., 14) value to indicate the presence of subsequent LLT information in the AID TID-specific information subfield. Therefore, STA1 can use an LLT BA frame to send LLT information to the AP simultaneously with ACK information for the data frame.

[0252] An AP that receives an LLT BA frame containing LLT information from STA1 can send a trigger frame to STA1, and STA1 can send LLT to the AP based on the trigger frame. As described above, the LLT BA frame may contain LLT information. The LLT BA frame may also contain LLT information equal to or greater than the length of the BA information field and may be applied to multi-TID.

[0253] Figure 19 is an embodiment of the present disclosure illustrating the configuration of an LLT BA frame for multi-TID and the procedure for transmitting and receiving LLT BAs. Specifically, Figure 19 relates to an example of an LLT BA frame for multi-TID that differs from Figure 18.

[0254] The AP can first obtain a TXOP through CTS / RTS exchange and then send a PPDU to STA1. In this example, the PPDU may include a multi-TID A-MPDU containing QoS data frames for TID1 and TID2, respectively. The PPDU may also include information to trigger STA1's LLT information transmission.

[0255] Upon receiving the PPDU, STA1 can respond to the AP with an LLT BA frame (i.e., a multi-STA BA frame containing LLT information or a new type of LLT BA frame). As shown in Figure 18, the LLT BA frame may include AID TID info for ACK information for the QoS data frames included in the A-MPDU (i.e., QoS data frames for TID1 and TID2).

[0256] Additionally, Per AID TID info, which includes LLT information, can indicate that LLT information is included in the LLT BA frame (i.e., LLT information follows the Per AID TID info) based on the specific AID, ACK type, and TID combination. For example, as shown in Figure 18, when the {specific AID, ACK type, TID} combination is set to {2020,0,0} or {0,0,8}, it may be indicated that LLT information is included in the LLT BA frame (or the Per AID TID info subfield for LLT included in the LLT BA frame).

[0257] As an addition or alternative, the fragment number field included in the LLT BA frame may indicate the length of the field containing the LLT information. For example, as shown in Figure 19, if the fragment number field (e.g., 4 bits (B3B2B1B0)) is indicated / set to a specific value (e.g., "0110"), the LLT information may be contained / set using the remaining fields of the total 6 octets (of the AID TID separate information subfield (for LLT)), excluding the fragment number field.

[0258] As an addition or alternative, the Starting Sequence Control field may be reserved. The names of the Fragment Number field, the Starting Sequence Control field, and the Block ACK field may be changed.

[0259] Therefore, STA1 can send LLT information to the AP simultaneously with ACK information for the data frame using an LL BA frame. Upon receiving an LLT BA frame containing LLT information from STA1, the AP can send a trigger frame to STA1, and STA1 can send LLT to the AP based on the trigger frame. As described above, the LLT BA frame may contain LLT information. Furthermore, the LLT BA frame may contain LLT information equal to or greater than the length of the BA information field and may be applied to multi-TID.

[0260] Example 1-2-3

[0261] As one embodiment of this disclosure, fields in the MAC header may be used to transmit LLT information.

[0262] As an example of this disclosure, an STA may send a PPDU (e.g., A-MPDU) to an AP that includes a more data field. The more data field may include LLT presence information indicating whether or not LLT information exists. For example, if an STA sends a PPDU with a more data field value set to 1, this can mean that LLT information exists for the STA to send to the AP.

[0263] As an addition or alternative, the STA may transmit a PPDU (e.g., A-MPDU) containing a QoS control field to the AP. When bit 4 of the QoS control field is set to 0 or 1, bit 7 of the QoS control field may indicate the presence or absence of LLT information and / or LLT presence. In this case, bit 7 of the QoS control field may be set to 0 or 1. As described above, when bit 4 of the QoS control field is set to 0 or 1 and bit 7 of the QoS control field is set to indicate the presence or absence of LLT information, LLT information may be set by at least one of bits 8 to 15 of the QoS control field.

[0264] Figure 20 is a diagram illustrating a method for transmitting LLT information using a MAC header according to one embodiment of the present disclosure.

[0265] As shown in Figure 20, the AP can first obtain a TXOP through RTS / CTS exchange and then send a PPDU to STA1. In this example, an A-MPDU containing a QoS data frame on the PPDU may be sent to STA1.

[0266] The PPDU may contain information that triggers STA1 to transmit LLT information. Upon receiving the PPDU, STA1 can use the A-MPDU to transmit a more data field and / or a QoS control field containing the LLT information to the AP. In this case, the more data field and / or the QoS control field may be included in the BA frame, QoS data frame, and / or QoS null frame of the A-MPDU.

[0267] As an example of this disclosure, if a BA frame includes a QoS control field, the BA frame may be defined as a new control frame or BA type. Therefore, STA1 can use the BA frame to transmit LLT information to the AP simultaneously with ACK information for the data frame.

[0268] For example, if the ACK policy is set to a policy that requires an immediate response to a BA frame (e.g., implicit BAR), the PPDU sent by the AP on the BA frame may include BA information for the MPDU (for QoS data). As another example, if the ACK policy is set to a policy that does not require an immediate response to a BA frame (e.g., the ACK policy is set to BA), the PPDU sent by the AP on the BA frame may not include BA information for the MPDU (for QoS data).

[0269] An AP that receives an LLT BA frame containing LLT information from STA1 can send a trigger frame to STA1. STA1 can include the LLT information in the MAC header of its response to the trigger frame (e.g., A-MPDU). In this disclosure, STA1 can send LLT information to the AP simultaneously with various frames (e.g., BA frames, data frames, etc.).

[0270] Example 2

[0271] Example 2 relates to the process of triggering LLT information and transmitting and receiving LLT information. That is, Example 2 embodies the LLT information triggering procedure and the LLT information transmission / reception procedure in Example 1 and its subordinate examples. As described above, the STA may be a non-AP STA or an AP.

[0272] As described in this disclosure, an STA (e.g., an AP) can acquire / initiate a TXOP by transmitting a frame / PPDU. Another STA (e.g., a non-AP STA) can receive one or more PPDUs from the STA (e.g., an AP) within the TXOP, each containing a frame that triggers Low Latency Traffic (LLT) information, where one or more PPDUs may contain frames (e.g., QoS data frames) addressed to one or more STAs.

[0273] Additionally, or as an alternative, a predefined time interval (e.g., SIFS, PIFS) may exist between the PPDU / frame that triggers the LLT information and the frame containing the LLT information that responds to that PPDU / frame.

[0274] An STA (e.g., an AP) that receives one or more frames / PPDUs containing LLT information can send frames / PPDUs that trigger LLT based on the LLT information to other STAs (e.g., non-AP STAs).

[0275] A STA that has received one or more frames containing LLT information can perform a frame detection operation, and can acquire LLT information for each STA through the frame detection operation. One or more STAs can use the acquired LLT information to prepare for transmission of a PPDU / frame that can trigger LLT. The configuration of LLT information has been described in Embodiment 1-1, and thus duplicate description is omitted. A STA that has received a PPDU / frame triggering LLT can perform frame detection, and can prepare for LLT transmission through frame detection.

[0276] As an example of the present disclosure, within a TXOP set by STA1, STA2 can transmit a frame including LLT information to STA1 and / or one or more other STAs. The LLT information may be transmitted to STA1 in a response frame to a frame triggering LLT information or another frame.

[0277] The LLT information may be transmitted and received via at least one of an HT control field (e.g., an A-Control field), a BA (block ACK) frame (e.g., a BA control field of a BA frame), or a MAC header. For example, when LLT information is included in a BA frame, the BA frame may be defined as a new BA type.

[0278] Additionally or alternatively, the field including LLT information may be located after or within the BA information field of a BA frame. Additionally or alternatively, when the BA frame is a compressed BA, the fragment number subfield of the block ACK starting sequence control field may be set to a specific value to indicate that LLT information is included in the BA frame. Additionally or alternatively, when the BA frame is a multi-STA BA frame, the AID TID information field of the Per AID TID Info subfield may be set to a specific value to indicate that LLT information is included in the BA frame.

[0279] 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.

[0280] 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.

[0281] 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, includes 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.

[0282] [Industrial applicability] 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.

[0283] [Claims when filing an international application] [Claim 1] A method performed by a first station (STA) in a wireless LAN system, The first physical layer protocol data unit (PPDU) is received from the access point (AP), A step of transmitting a block acknowledgment (BA) frame to the AP for the first PPDU, wherein the BA frame includes low latency traffic (LLT) information. The transmission opportunity (TXOP) includes the step of transmitting the LLT information and the associated LLT to the AP, A method wherein the BA frame includes at least one field related to whether or not the LLT information is included on the BA frame. [Claim 2] The aforementioned AP is a TXOP holder. The method according to claim 1, wherein either the first STA or the second STA is a TXOP responder. [Claim 3] The method according to claim 1, wherein the first PPDU includes information that triggers the transmission of the LLT information. [Claim 4] The method according to claim 1, wherein the at least one field includes an AID (association identification) 11 field, an ACK type field, and a TID (traffic identifier) ​​field. [Claim 5] The aforementioned AID 11 field value is set to the first value, The aforementioned ACK type field value is set to the second value, The method according to claim 4, wherein, based on the setting of the TID field value to a third value, the combination of the AID 11 field, the ACK type field, and the TID field indicates that the LLT information is included on the BA frame. [Claim 6] The BA information field of the aforementioned BA frame includes a Per AID TID Info field for LLT, The method according to claim 1, wherein the Per AID TID Info field includes the at least one field and a fragment number field. [Claim 7] The fragment number field indicates the length of the LLT information, or the total length of the field containing the LLT information. The method according to claim 6, wherein the LLT information is set in the BA information field following the fragment field. [Claim 8] The method according to claim 6, wherein the BA information includes ACK information for the QoS (quality of service) data included in the first PPDU. [Claim 9] The method according to claim 1, wherein the LLT information includes at least one of the following: identification information of the LLT, information regarding the time at which the LLT should have completed transmission, and information regarding the amount of the LLT. [Claim 10] A first station (STA) operating in a wireless LAN system, The aforementioned 1STA is, One or more transceivers, The system comprises one or more processors connected to one or more of the aforementioned transceivers, The one or more processors described above are: A first physical layer protocol data unit (PPDU) is received from an access point (AP) via one or more transceivers. transmit, to the AP via the one or more transceivers, a block acknowledgement (BA) frame for the first PPDU, wherein the BA frame comprises low latency traffic (LLT) information, configured to transmit, within a transmission opportunity (TXOP), LLT associated with the LLT information to the AP via the one or more transceivers, the first STA, wherein the BA frame comprises at least one field associated with whether the LLT information is included on the BA frame. [Claim 11] A method performed by an access point (AP) in a wireless LAN system, comprising: receiving a first physical layer protocol data unit from at least one STA; receiving, from the at least one STA, a block acknowledgement (BA) frame for the first PPDU, wherein the BA frame comprises low latency traffic (LLT) information; receiving, within a transmission opportunity (TXOP), LLT associated with the LLT information from the at least one STA, the method, wherein the BA frame comprises at least one field associated with whether the LLT information is included on the BA frame. [Claim 12] An access point (AP) operating in a wireless LAN system, comprising: one or more transceivers; one or more processors coupled to the one or more transceivers, wherein the one or more processors are A first physical layer protocol data unit (PPDU) is received from at least one STA via one or more transceivers. A block acknowledgment (BA) frame for the first PPDU is received from at least one STA via one or more transceivers, and the BA frame includes low latency traffic (LLT) information. During a transmission opportunity (TXOP), the system is configured to receive the LLT information and associated LLTs from at least one STA via one or more transceivers. The BA frame includes at least one field related to whether or not the LLT information is included in the BA frame, and the AP. [Claim 13] A processing device configured to control a first station (STA) operating in a wireless LAN system, One or more processors, The system comprises one or more computer memories that are operably connected to one or more processors and store instructions for performing operations based on execution by the one or more processors, The aforementioned operation is, The operation of receiving a first physical layer protocol data unit (PPDU) from an access point (AP), An operation to transmit a block acknowledgment (BA) frame to the AP for the first PPDU, wherein the BA frame includes low latency traffic (LLT) information. The operation includes, within a transmission opportunity (TXOP), transmitting the LLT information and the associated LLT to the AP, A processing device wherein the BA frame includes at least one field related to whether or not the LLT information is included on the BA frame. [Claim 14] One or more non-transitory computer-readable media for storing one or more instructions, The aforementioned one or more instructions are executed by one or more processors, and the device operating in the wireless LAN system is, The physical layer protocol data unit (PPDU) is received from the access point (AP). In the step of transmitting a block acknowledgment (BA) frame to the AP for the first PPDU, the BA frame includes low latency traffic (LLT) information. Within a transmission opportunity (TXOP), the system is controlled to transmit the LLT information and the associated LLT to the AP. The BA frame is a computer-readable medium that includes at least one field related to whether or not the LLT information is included on the BA frame.

Claims

1. A method performed by a first station (STA) in a wireless LAN system, The first physical layer protocol data unit (PPDU) is received from the access point (AP), The step of transmitting a block ACK (block acknowledged, BA) frame to the AP for the first PPDU, wherein the BA frame includes low latency traffic (LLT) information. The process includes the step of transmitting the LLT information and related LLT to the AP within a transmission opportunity (TXOP), A method wherein the BA frame includes at least one field related to whether or not the LLT information is included on the BA frame.

2. The aforementioned AP is a TXOP holder. The method according to claim 1, wherein either the first STA or the second STA is a TXOP responder.

3. The method according to claim 1, wherein the first PPDU includes information that triggers the transmission of the LLT information.

4. The method according to claim 1, wherein the at least one field includes an AID (association identification) 11 field, an ACK type field, and a TID (traffic identifier) ​​field.

5. The AID 11 field value is set to the first value, The aforementioned ACK type field value is set to the second value, The method according to claim 4, wherein, based on the setting of the TID field value to a third value, the combination of the AID 11 field, the ACK type field, and the TID field indicates that the LLT information is included on the BA frame.

6. The BA information field of the BA frame includes a Per AID TID Info field for LLT, The method according to claim 1, wherein the Per AID TID Info field includes the at least one field and a fragment number field.

7. The fragment number field indicates the length of the LLT information, or the total length of the field containing the LLT information. The method according to claim 6, wherein the LLT information is set in the BA information field following the fragment field.

8. The method according to claim 6, wherein the BA information includes ACK information for the QoS (quality of service) data included in the first PPDU.

9. The method according to claim 1, wherein the LLT information includes at least one of the following: identification information of the LLT, information regarding the time at which the LLT should be completed to transmit, and information regarding the quantity of the LLT.

10. A first station (STA) operating in a wireless LAN system, The first STA is, One or more transceivers, The system comprises one or more processors connected to one or more of the aforementioned transceivers, The one or more processors described above are: A first physical layer protocol data unit (PPDU) is received from an access point (AP) via one or more transceivers. A block ACK (BA) frame for the first PPDU is transmitted to the AP via the one or more transceivers, and the BA frame includes low latency traffic (LLT) information. Within a transmission opportunity (TXOP), the LLT information and related LLTs are configured to be transmitted to the AP via one or more transceivers. The BA frame includes a first STA which includes at least one field related to whether or not the LLT information is included in the BA frame.

11. A method performed by an access point (AP) in a wireless LAN system, The steps include receiving a first physical layer protocol data unit from at least one STA, A step of receiving a block ACK (BA) frame for the first PPDU from at least one STA, wherein the BA frame includes low latency traffic (LLT) information, The transmission opportunity (TXOP) includes the step of receiving the LLT information and related LLT from at least one STA, A method wherein the BA frame includes at least one field related to whether or not the LLT information is included on the BA frame.

12. An access point (AP) that operates in a wireless LAN system, One or more transceivers, The system comprises one or more processors connected to one or more of the aforementioned transceivers, The one or more processors described above are: A first physical layer protocol data unit (PPDU) is received from at least one STA via one or more transceivers. Block ACK (BA) frames for the first PPDU are received from at least one STA via one or more transceivers, and the BA frames include low latency traffic (LLT) information. Within a transmission opportunity (TXOP), the system is configured to receive the LLT information and related LLTs from at least one STA via one or more transceivers. The BA frame includes at least one field related to whether or not the LLT information is included in the BA frame, AP.

13. A processing device configured to control a first station (STA) operating in a wireless LAN system, One or more processors, The system comprises one or more computer memories that are operably connected to one or more processors and store instructions for performing operations based on execution by the one or more processors, The aforementioned operation is, The operation of receiving a first physical layer protocol data unit (PPDU) from an access point (AP), An operation to transmit a block ACK (block acknowledged, BA) frame to the AP for the first PPDU, wherein the BA frame includes low latency traffic (LLT) information. The operation includes, within a transmission opportunity (TXOP), transmitting the LLT information and related LLT to the AP, A processing device wherein the BA frame includes at least one field related to whether or not the LLT information is included on the BA frame.

14. One or more non-transitory computer-readable media for storing one or more instructions, The aforementioned one or more instructions are executed by one or more processors, and the device operating in the wireless LAN system is, The first physical layer protocol data unit (PPDU) is received from the access point (AP), In the step of transmitting a block ACK (BA) frame to the AP for the first PPDU, the BA frame includes low latency traffic (LLT) information. Within a transmission opportunity (TXOP), the system is controlled to transmit the LLT information and the associated LLT to the AP. The BA frame is a computer-readable medium that includes at least one field related to whether or not the LLT information is included on the BA frame.

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