Method and apparatus for directing links for specific types of traffic in a wireless LAN system

Abstract

A method and apparatus for indicating links for a specific type of traffic in a wireless local area network (WLAN) system are disclosed. A method performed by a first station (STA) in a WLAN system according to an embodiment of the present disclosure may include transmitting a stream classification service (SCS) request frame to a second station (STA), the SCS request frame including information related to negotiation of the specific type of traffic, and receiving an SCS response frame from the second station in response to the SCS request frame. Here, at least one of the SCS request frame or the SCS response frame may include link-related information indicating one or more links over which the specific type of traffic is transmitted or received.

Description

[Technical Field]

[0001] The present disclosure relates to a method and apparatus for directing links for specific types of traffic in a Wireless Local Area Network (WLAN) system. [Background technology]

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

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

[0004] The technical problem of the present disclosure is to provide a method and apparatus for directing links for specific types of traffic.

[0005] A technical problem of the present disclosure is to provide a method and apparatus for directing links for low latency traffic based on a stream classification service (SCS) negotiation procedure.

[0006] The technical problems to be solved by the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the following description. [Means for solving the problem]

[0007] A method performed by a first station (STA) in a wireless LAN system according to one embodiment of the present disclosure may include transmitting a stream classification service (SCS) request frame to a second STA, the stream classification service (SCS) request frame including information related to negotiation of a specific type of traffic, and receiving an SCS response frame from the second STA in response to the SCS request frame, wherein at least one of the SCS request frame or the SCS response frame may include (may comprise; may configure; may establish; may include; may contain; may have) link-related information indicating one or more links over which the specific type of traffic is transmitted or received.

[0008] According to a further aspect of the present disclosure, a method performed by a second STA in a WLAN system may include receiving a stream classification service (SCS) request frame from a first STA, the SCS request frame including information related to negotiation of a specific type of traffic, and transmitting an SCS response frame to the first STA in response to the SCS request frame, wherein at least one of the SCS request frame or the SCS response frame may include link-related information indicating one or more links over which the specific type of traffic is transmitted or received. [Effects of the Invention]

[0009] According to the present disclosure, methods and apparatus for directing links for particular types of traffic can be provided.

[0010] According to the present disclosure, a method and apparatus for directing links for low latency traffic based on a stream classification service (SCS) negotiation procedure can be provided.

[0011] The effects obtained from the present disclosure are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those having ordinary skill in the art to which the present disclosure pertains from the following description. [Brief explanation of the drawings]

[0012] The accompanying drawings, which are included as part of the detailed description to aid in understanding the present disclosure, provide examples for the present disclosure and, together with the detailed description, explain the technical features of the present disclosure. [Figure 1] FIG. 1 is a block diagram illustrating a wireless communication device according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a diagram illustrating an exemplary structure of a wireless LAN system to which the present disclosure can be applied. [Figure 3]FIG. 1 is a diagram illustrating a link setup process to which the present disclosure can be applied. [Figure 4] FIG. 10 is a diagram illustrating a backoff process to which the present disclosure can be applied. [Figure 5] 10A and 10B are diagrams for explaining a CSMA / CA base frame transmission operation to which the present disclosure can be applied. [Figure 6] 1 is a diagram illustrating an example of a frame structure used in a wireless LAN system to which the present disclosure can be applied. [Figure 7] FIG. 1 illustrates an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure is applicable. [Figure 8] FIG. 2 illustrates an example of quality of service (QoS) characteristic elements applicable to an embodiment of the present disclosure. [Figure 9] FIG. 1 illustrates an example of an SCS descriptor element applicable to an embodiment of the present disclosure. [Figure 10] FIG. 10 illustrates an example of an MLO link information element according to an embodiment of the present disclosure. [Figure 11] FIG. 10 illustrates an example of an SCS descriptor element including a link information element according to an embodiment of the present disclosure. [Figure 12] FIG. 10 illustrates an example QoS characteristic element including a link ID bitmap field according to an embodiment of the present disclosure. [Figure 13] 10 is a flowchart illustrating an operation by a first STA according to an embodiment of the present disclosure. [Figure 14] 10 is a flowchart illustrating an operation by a second STA according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. The detailed description disclosed below together with the accompanying drawings is intended to describe exemplary embodiments of the present disclosure and is not intended to represent the only embodiments in which the present disclosure can be implemented. The detailed description below includes specific details to provide a complete understanding of the present disclosure. However, it will be understood by those skilled in the art that the present disclosure can be implemented without such specific details.

[0014] In some cases, in order to avoid obscuring the concepts of the present disclosure, known structures and devices may be omitted or shown in block diagram form, focusing on the core functions of each structure and device.

[0015] In this disclosure, when a component is "coupled," "coupled," or "connected" to another component, this may include a direct connection as well as an indirect connection where there is another component between them. Also, in this disclosure, the terms "comprise" or "have" specify the presence of stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0016] In this disclosure, terms such as "first" and "second" are used only to distinguish one component from another, and are not used to limit the components, and do not limit the order or importance of the components unless otherwise specified. Therefore, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

[0017] The terms used in this disclosure are for the purpose of describing particular embodiments and are not intended to limit the scope of the claims. As used in the description of the embodiments and the appended claims, the singular is intended to include the plural unless the context clearly dictates otherwise. The term "and / or" as used in this disclosure means that one of the associated listed items may be included, or that any and all possible combinations of two or more of them are included. Also, in this disclosure, " / " between words has the same meaning as "and / or" unless otherwise specified.

[0018] The examples of the present disclosure may be applied to various wireless communication systems. For example, the examples of the present disclosure may be applied to a wireless LAN system. For example, the examples of the present disclosure may be applied to a wireless LAN based on the IEEE 802.11a / g / n / ac / ax / be standard. Note that the examples of the present disclosure may also be applied to a newly proposed IEEE 802.11bn (or UHR) standard-based wireless LAN. Furthermore, the examples of the present disclosure may also be applied to a next-generation standard-based wireless LAN after IEEE 802.11bn. Furthermore, the examples of the present disclosure may also be applied to a cellular wireless communication system. For example, the examples of the present disclosure may be applied to a cellular wireless communication system based on the LTE (Long Term Evolution) series technology and the 5G NR (New Radio) series technology of the 3GPP (3rd Generation Partnership Project: registered trademark; the same applies hereinafter) standard.

[0019] Below, technical features to which the examples of the present disclosure can be applied will be described.

[0020] FIG. 1 is a block diagram illustrating a wireless communication device according to an embodiment of the present disclosure.

[0021] 1 may be referred to by various terms such as a terminal, a wireless device, a wireless transmit receive unit (WTRU), a user equipment (UE), a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a mobile subscriber unit (MSS), a subscriber station (SS), an advanced mobile station (AMS), a wireless terminal (WT), or simply a user. In addition, the first device 100 and the second device 200 may be referred to by various terms such as an access point (AP), a base station (BS), a fixed station, a Node B, a base transceiver system (BTS), a network, an artificial intelligence (AI) system, a road side unit (RSU), a repeater, a router, a relay, a gateway, etc.

[0022] The devices 100 and 200 illustrated in FIG. 1 may also be referred to as stations (STAs). For example, the devices 100 and 200 illustrated in FIG. 1 may be referred to by various terms, such as a transmitting device, a receiving device, a transmitting STA, or a receiving STA. For example, the STAs 110 and 200 may serve as an access point (AP) or a non-AP. That is, in the present disclosure, the STAs 110 and 200 may have AP and / or non-AP functionality. When the STAs 110 and 200 have AP functionality, they may simply be referred to as APs, and when the STAs 110 and 200 have non-AP functionality, they may simply be referred to as STAs. Also, in the present disclosure, an AP may be referred to as an AP STA.

[0023] 1, a first device 100 and a second device 200 may transmit and receive wireless signals using various wireless LAN technologies (e.g., the IEEE 802.11 family). The first device 100 and the second device 200 may include interfaces for a medium access control (MAC) layer and a physical layer (PHY) in accordance with the IEEE 802.11 standard.

[0024] In addition, the first device 100 and the second device 200 may further support various communication standards (e.g., 3GPP LTE series, 5G NR series standards, etc.) other than WLAN technology. Furthermore, the devices of the present disclosure may be embodied as various devices such as mobile phones, vehicles, personal computers, augmented reality (AR) equipment, and virtual reality (VR) equipment. Furthermore, the STAs of the present disclosure may support various communication services such as voice calls, video calls, data communications, autonomous driving, machine-type communication (MTC), machine-to-machine (M2M), device-to-device (D2D), and Internet-of-Things (IoT).

[0025] The first device 100 includes one or more processors 102 and one or more memories 104, and may additionally include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may be configured to control the memory 104 and / or the transceiver 106 to implement the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts of the present disclosure. For example, the processor 102 may process information in the memory 104 to generate first information / signals, and then transmit a wireless signal including the first information / signals via the transceiver 106. The processor 102 may also receive a wireless signal including 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 coupled to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may store software code including instructions for executing some or all of the processes controlled by the processor 102 or for implementing the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts in this disclosure. Here, the processor 102 and the memory 104 may be part of a communications modem / circuit / chip designed to implement wireless LAN technology (e.g., the IEEE 802.11 series). The transceiver 106 may be coupled to the processor 102 and may transmit and / or receive wireless signals via one or more antennas 108. The transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be used interchangeably with an RF (Radio Frequency) unit. In this disclosure, a device may also refer to a communications modem / circuit / chip.

[0026] The second device 200 includes one or more processors 202, one or more memories 204, and may additionally include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may be configured to control the memory 204 and / or the transceiver 206 to implement the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in this disclosure. For example, the processor 202 may process information in the memory 204 to generate third information / signal, and then transmit a wireless signal including the third information / signal via the transceiver 206. The processor 202 may also receive a wireless signal including fourth information / signal via the transceiver 206, and then store information obtained from signal processing of the fourth information / signal in the memory 204. The memory 204 may be coupled to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may store software code including instructions for executing some or all of the processes controlled by the processor 202 or for implementing the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in this disclosure. Here, the processor 202 and the memory 204 may be part of a communications modem / circuit / chip designed to implement wireless LAN technology (e.g., the IEEE 802.11 series). The transceiver 206 may be coupled to the processor 202 and may transmit and / or receive wireless signals via one or more antennas 208. The transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be used interchangeably with an RF unit. In this disclosure, a device may also refer to a communications modem / circuit / chip.

[0027] The hardware elements of the devices 100 and 200 are described in more detail below. Without limitation, one or more protocol layers may be implemented by one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., the same functional layer, such as PHY or MAC). The one or more processors 102 and 202 may generate one or more protocol data units (PDUs) and / or one or more service data units (SDUs) according to the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams in this disclosure. The one or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams in this disclosure. The one or more processors 102, 202 can generate and provide signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, suggestions, and / or methods of this disclosure to the one or more transceivers 106, 206. The one or more processors 102, 202 can receive signals (e.g., baseband signals) from the one or more transceivers 106, 206 and obtain the PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts of this disclosure.

[0028] The one or more processors 102, 202 may be referred to as a controller, microcontroller, microprocessor, or microcomputer. The one or more processors 102, 202 may be implemented using hardware, firmware, software, or a combination thereof. As an example, the one or more processors 102, 202 may include one or more application-specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs). The descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in this disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. Firmware or software configured to execute the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in this disclosure may be included in one or more processors 102, 202 or stored in one or more memories 104, 204 and executed by one or more processors 102, 202. The descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in this disclosure may be embodied by firmware or software in the form of code, instructions, and / or collections of instructions.

[0029] One or more memories 104, 204 may be coupled to one or more processors 102, 202 and may store various types of data, signals, messages, information, programs, code, instructions, and / or instructions. The one or more memories 104, 204 may be comprised of ROM, RAM, EPROM, flash memory, hard drives, registers, cache memory, computer-readable storage media, and / or combinations thereof. The one or more memories 104, 204 may be located internal and / or external to the one or more processors 102, 202. Additionally, the one or more memories 104, 204 may be coupled to the one or more processors 102, 202 via various techniques, such as wired or wireless connections.

[0030] One or more transceivers 106, 206 may transmit user data, control information, wireless signals / channels, etc., as referred to in the methods and / or operational flowcharts of the present disclosure, to one or more other devices. One or more transceivers 106, 206 may receive user data, control information, wireless signals / channels, etc., as referred to in the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts of the present disclosure, from one or more other devices. For example, one or more transceivers 106, 206 may be coupled to one or more processors 102, 202 and may transmit and receive wireless signals. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other devices. Also, one or more processors 102, 202 may control one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. Furthermore, one or more transceivers 106, 206 may be coupled to one or more antennas 108, 208, and may be configured to transmit or receive user data, control information, wireless signals / channels, etc., as referred to in the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in this disclosure, via the one or more antennas 108, 208. In this disclosure, the one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). The one or more transceivers 106, 206 may convert the received user data, control information, wireless signals / channels, etc., from RF band signals to baseband signals for processing using one or more processors 102, 202. The one or more transceivers 106, 206 may convert the user data, control information, wireless signals / channels, etc., processed using one or more processors 102, 202, from baseband signals to RF band signals. To that end, one or more of the transceivers 106, 206 may include (analog) oscillators and / or filters.

[0031] For example, one of the STAs 100 and 200 may perform operations intended for an AP, and the other of the STAs 100 and 200 may perform operations intended for a non-AP STA. For example, the transceivers 106 and 206 in FIG. 1 may perform operations for transmitting and receiving signals (e.g., packets or PPDUs (Physical Layer Protocol Data Units) conforming to IEEE 802.11a / b / g / n / ac / ax / be, etc.). In addition, in the present disclosure, operations for various STAs to generate transmission / reception signals or to perform data processing or calculations in advance for transmission / reception signals may be performed by the processors 102 and 202 in FIG. 1. For example, examples of operations for generating transmission / reception signals or performing data processing or calculations in advance for transmission / reception signals may include: 1) operations for determining / obtaining / configuring / calculating / decoding / encoding bit information of fields included in a PPDU (SIG (signal), STF (short training field), LTF (long training field), Data, etc.); 2) operations for determining / configuring / obtaining time resources and frequency resources (e.g., subcarrier resources) to be used for fields included in a PPDU (SIG, STF, LTF, Data, etc.); 3) operations for determining / configuring / obtaining specific sequences (e.g., pilot sequences, STF / LTF sequences, extra sequences applied to SIG) to be used for fields included in a PPDU (SIG, STF, LTF, Data, etc.); 4) power control operations and / or power saving operations applied to STAs; and 5) operations related to determining / obtaining / configuring / calculating / decoding / encoding ACK signals, etc. In addition, in the example below, various information (e.g., information regarding fields / subfields / control fields / parameters / power, etc.) used by various STAs to determine / acquire / configure / calculate / decode / encode transmitted / receive signals may be stored in memories 104, 204 of FIG. 1.

[0032] Hereinafter, downlink (DL) refers to a link for communication from an AP STA to a non-AP STA, and downlink PPDUs / packets / signals, etc. may be transmitted and received via the downlink. In downlink communication, the transmitter may be part of the AP STA, and the receiver may be part of the non-AP STA. Uplink (UL) refers to a link for communication from a non-AP STA to an AP STA, and uplink PPDUs / packets / signals, etc. may be transmitted and received via the uplink. In uplink communication, the transmitter may be part of the non-AP STA, and the receiver may be part of the AP STA.

[0033] FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0034] The structure of a WLAN system may be composed of multiple components. The interaction of these components may provide a WLAN that supports STA mobility transparent to higher layers. A Basic Service Set (BSS) is a basic building block of a WLAN. FIG. 2 illustrates two BSSs (BSS1 and BSS2), each including two STAs as members (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). The ellipses representing BSSs in FIG. 2 may be understood to represent coverage areas where STAs included in the BSSs maintain communication. This area may be referred to as a Basic Service Area (BSA). If a STA moves outside a BSA, it will no longer be able to directly communicate with other STAs within the BSA.

[0035] Ignoring the DS shown in FIG. 2, the most basic type of BSS in a WLAN is the Independent BSS (IBSS). For example, an IBSS may have a minimal configuration consisting of only two STAs. For example, assuming that other components are omitted, BSS1 consisting of only STA1 and STA2, or BSS2 consisting of only STA3 and STA4, are representative examples of an IBSS. Such a configuration is possible when STAs can communicate directly without an AP. Furthermore, in such a WLAN, a BSS may be configured when needed by the LAN, rather than being configured in advance. This can also be called an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. That is, in an IBSS, STAs are managed in a distributed manner. In an IBSS, all STAs may be mobile, and connection to a distributed system (DS) is not permitted, forming a self-contained network.

[0036] The membership of STAs in a BSS may change dynamically as STAs join and leave the BSS area, etc. To become a member of a BSS, a STA may join the BSS using a synchronization process. To access all the services of the BSS-based architecture, a STA must be associated with the BSS. Such association may be dynamically configured and may include the use of a Distribution System Service (DSS).

[0037] In a wireless LAN, direct STA-to-STA distance may be limited by PHY performance. While such distance limits are sufficient in some cases, other situations may require communication between STAs over longer distances. To support extended coverage, a distributed system (DS) may be configured.

[0038] A DS refers to a structure in which BSSs are interconnected. Specifically, as shown in FIG. 2, a BSS may exist as a component of an expanded network composed of multiple BSSs. A DS is a logical concept and may be specified by the characteristics of a distributed system medium (DSM). In this regard, a wireless medium (WM) and a DSM may be logically distinguished. Each logical medium is used for different purposes and by different components. These media are neither limited to being the same nor limited to being different. The flexibility of a WLAN structure (DS structure or other network structure) can be explained by the fact that multiple media are logically distinct from one another. That is, a WLAN structure may be embodied in various ways, and the WLAN structure may be independently specified according to the physical characteristics of each implementation.

[0039] The DS can support mobile devices by providing seamless integration of multiple BSSs and logical services necessary for addressing destinations. The DS may also include a portal component that acts as a bridge between the wireless LAN and other networks (e.g., IEEE 802.X).

[0040] An AP is an entity that allows associated non-AP STAs to access the DS through the WM and also has the functionality of an STA. Data can be transferred between a BSS and a DS via the AP. For example, STA2 and STA3 shown in FIG. 2 have the functionality of an STA and provide the function of allowing associated non-AP STAs (STA1 and STA4) to access the DS. Furthermore, since all APs essentially correspond to STAs, all APs are addressable entities. The address used by an AP for communication on the WM does not necessarily have to be the same as the address used by the AP for communication on the DSM. A BSS consisting of an AP and one or more STAs can be called an infrastructure BSS.

[0041] Data transmitted from one of the STAs associated with an AP to the STA address of that AP is always received on the uncontrolled port and may be processed by the IEEE 802.1X port access entity, and once the controlled port is authenticated, the transmitted data (or frame) may be delivered to the DS.

[0042] In the above-described DS structure, an Extended Service Set (ESS) may be configured to provide wider coverage.

[0043] An ESS is a network of arbitrary size and complexity composed of a DS and a BSS. An ESS can correspond to a collection of BSSs connected to one DS. However, an ESS does not include a DS. An ESS network is characterized by appearing as an IBSS at the Logical Link Control (LLC) layer. STAs included in an ESS can communicate with each other, and mobile STAs can move from one BSS to another (within the same ESS) transparently to the LLC. APs included in one ESS may have the same service set identification (SSID). An SSID is distinct from a BSSID, which is an identifier for a BSS.

[0044] A WLAN system does not make any assumptions about the relative physical locations of BSSs and can have any of the following configurations: BSSs may partially overlap, which is a configuration commonly used to provide continuous coverage; BSSs may not be physically connected, and there is no logical limit to the distance between BSSs; BSSs may be physically located in the same location, which may be used to provide redundancy; and one (or more) IBSS or ESS networks may physically exist in the same space as one (or more) ESS networks. This may apply to ESS network configurations when an ad-hoc network operates in the location where the ESS network exists, when physically overlapping wireless networks are formed by different organizations, or when two or more different access and security policies are required in the same location.

[0045] FIG. 3 is a diagram illustrating a link setup process to which the present disclosure can be applied.

[0046] In order for an STA to set up a link to a network and transmit and receive data, it must first discover the network, perform authentication, establish an association, and perform authentication procedures for security. The link setup process can also be called a session initiation process or a session setup process. In addition, the discovery, authentication, association, and security configuration processes of the link setup process can also be collectively called the association process.

[0047] In step S310, the STA may perform a network discovery operation. The network discovery operation may include a scanning operation of the STA. That is, in order for the STA to access a network, the STA must search for a joinable network. Before joining a wireless network, the STA must identify a compatible network. The process of identifying networks present in a specific area is called scanning.

[0048] Scanning methods include active scanning and passive scanning. FIG. 3 illustrates an example of a network discovery operation including an active scanning process. In active scanning, a scanning STA changes channels and transmits a probe request frame to search for nearby APs, and waits for a response. A responder transmits a probe response frame to the STA that transmitted the probe request frame in response to the probe request frame. Here, the responder may be the STA that last transmitted a beacon frame in the BSS of the channel being scanned. In a BSS, the AP transmits beacon frames, so the AP is the responder. In an IBSS, the STAs in the IBSS transmit beacon frames alternately, so the responder is not constant. For example, an STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 can store the BSS-related information contained in the received probe response frame, move to the next channel (e.g., channel 2), and perform scanning in the same manner (i.e., send and receive probe requests / responses on channel 2).

[0049] Although not shown in FIG. 3, the scanning operation may be performed in a passive scanning manner. In passive scanning, a scanning STA waits for a beacon frame while changing channels. A beacon frame is a management frame defined in IEEE 802.11 and is periodically transmitted to announce the existence of a wireless network and allow a scanning STA to search for and join the wireless network. In a BSS, the AP is responsible for periodically transmitting beacon frames, while in an IBSS, STAs within the IBSS transmit beacon frames in turn. When a scanning STA receives a beacon frame, it saves the BSS-related information included in the beacon frame and records the beacon frame information on each channel as it moves to other channels. A STA that receives a beacon frame saves the BSS-related information included in the received beacon frame, moves to the next channel, and scans the next channel in the same manner. Comparing active scanning with passive scanning, active scanning has the advantage of having a smaller delay and power consumption than passive scanning.

[0050] After the STA discovers the network, an authentication process may be performed in step S320. This authentication process may be called a first authentication process to clearly distinguish it from the security setup operation in step S340, which will be described later.

[0051] The authentication process involves a STA sending an authentication request frame to an AP, and the AP responding by sending an authentication response frame to the STA. The authentication frame used for the authentication request / response corresponds to a management frame.

[0052] The authentication frame may include information such as an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a Robust Security Network (RSN), a Finite Cyclic Group, etc. These are only examples of information that may be included in an authentication request / response frame, and other information may be substituted or additional information may be included.

[0053] The STA can send an authentication request frame to the AP. The AP can determine whether to allow authentication for the STA based on the information contained in the received authentication request frame. The AP can provide the STA with the result of the authentication process using an authentication response frame.

[0054] After the STA is successfully authenticated, an association process may be performed in step S330. The association process includes a process in which the STA transmits an association request frame to the AP, and in response, the AP transmits an association response frame to the STA.

[0055] For example, the association request frame may include information on various capabilities, a beacon listen interval, a service set identifier (SSID), supported rates, supported channels, an RSN, a mobility domain, supported operating classes, a Traffic Indication Map Broadcast request, interworking service capabilities, etc. For example, the association response frame may include information on various capabilities, a status code, an association ID (AID), supported rates, an Enhanced Distributed Channel Access (EDCA) parameter set, a Received Channel Power Indicator (RCPI), a Received Signal to Noise Indicator (RSNI), a mobility domain, a timeout interval (e.g., an association comeback time), overlapping BSS scan parameters, a TIM broadcast response, a Quality of Service (QoS) map, etc. This corresponds to only a partial example of information that may be included in the association request / response frame, and other information may be substituted or additional information may be included.

[0056] After the STA is successfully connected to the network, a security setup process may be performed in step S340. The security setup process in step S340 may also be referred to as an authentication process using a Robust Security Network Association (RSNA) request / response, and the authentication process in step S320 may be referred to as a first authentication process, and the security setup process in step S340 may simply be referred to as an authentication process.

[0057] The security setup process of step S340 may include a process of performing private key setup using, for example, four-way handshaking using an Extensible Authentication Protocol over LAN (EAPOL) frame, and may also be performed using a security method not defined in the IEEE 802.11 standard.

[0058] FIG. 4 is a diagram illustrating a backoff process to which the present disclosure can be applied.

[0059] In wireless LAN systems, the basic access mechanism of MAC (Medium Access Control) is the Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) mechanism, also known as the Distributed Coordination Function (DCF) of IEEE 802.11 MAC, which basically employs a "listen before talk" access mechanism. According to this type of access mechanism, the AP and / or STA can perform a Clear Channel Assessment (CCA) to sense the wireless channel or medium for a predetermined time period (e.g., a DCF Inter-Frame Space (DIFS)) before starting transmission. If the sensing result indicates that the medium is in an idle status, the AP and / or STA can start transmitting a frame over the medium. On the other hand, if the medium is detected as occupied or busy, the AP and / or STA can wait for a delay period (e.g., a random backoff period) for medium access without starting its own transmission, and then attempt to transmit a frame. By applying the random backoff period, multiple STAs are expected to wait for different periods of time before attempting to transmit a frame, thereby minimizing collisions.

[0060] The IEEE 802.11 MAC protocol also provides a Hybrid Coordination Function (HCF). HCF is based on the DCF and Point Coordination Function (PCF). PCF is a polling-based synchronous access method that periodically polls all receiving APs and / or STAs to receive data frames. HCF also includes Enhanced Distributed Channel Access (EDCA) and HCF Controlled Channel Access (HCCA). EDCA is a contention-based access method for a provider to provide data frames to multiple users, while HCCA is a non-contention-based channel access method using a polling mechanism. HCF also includes a medium access mechanism for improving the quality of service (QoS) of wireless LANs and can transmit QoS data in both the contention period (CP) and the contention-free period (CFP).

[0061] An operation based on a random backoff period will be described with reference to FIG. 4. When an occupied / busy medium changes to an idle state, multiple STAs can attempt to transmit data (or frames). As a method for minimizing collisions, each STA can select a random backoff count and wait for the corresponding slot time before attempting transmission. The random backoff count has a pseudo-random integer value and may be determined to be one of the values ​​ranging from 0 to CW. Here, CW is a contention window parameter value. The CW parameter is initially set to CWmin, but can double in the event of a transmission failure (e.g., if an ACK for a transmitted frame is not received). When the CW parameter value reaches CWmax, data transmission can be attempted while maintaining the CWmax value until data transmission is successful, and if data transmission is successful, the CW parameter is reset to the CWmin value. The CW, CWmin, and CWmax values ​​are preferably set to 2n-1 (n=0, 1, 2, ...).

[0062] When the random backoff process begins, the STA continuously monitors the medium while counting down the backoff slots according to the determined backoff count value. If the medium is monitored as occupied, the STA stops counting down and waits. If the medium becomes idle, the STA resumes the remaining countdown.

[0063] In the example of FIG. 4, when a packet to be transmitted arrives at the MAC of STA3, STA3 confirms that the medium is idle for DIFS and can immediately transmit a frame. The remaining STAs monitor the medium for occupied / busy status and wait. Meanwhile, STA1, STA2, and STA5 may each have data to transmit. If each STA monitors the medium as idle, it waits for DIFS and then counts down its backoff slots according to its random backoff count value. Assume that STA2 selects the smallest backoff count value and STA1 selects the largest backoff count value. That is, this example illustrates a case where, at the time STA2 finishes its backoff count and begins frame transmission, STA5's remaining backoff time is shorter than STA1's remaining backoff time. STA1 and STA5 pause their countdowns and wait while STA2 occupies the medium. When STA2's occupation ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and then resume their backoff counts. That is, STA5 can start frame transmission after counting down the remaining backoff slots equal to the remaining backoff time. Because STA5's remaining backoff time is shorter than STA1's, STA5 begins frame transmission. While STA2 is occupying the medium, STA4 may also have data to transmit. From STA4's perspective, when the medium becomes idle, it waits for DIFS, then counts down the random backoff count value it selected, and can begin frame transmission. The example in FIG. 4 shows a case where STA5's remaining backoff time happens to match STA4's random backoff count value, which may result in a collision between STA4 and STA5. If a collision occurs, neither STA4 nor STA5 will receive an ACK, resulting in a failed data transmission. In this case, STA4 and STA5 can double their CW values, select a random backoff count value, and then count down.STA1 waits while the medium is occupied by transmissions from STA4 and STA5, but when the medium becomes idle, it waits for DIFS and can begin frame transmission once the remaining backoff time has elapsed.

[0064] As shown in the example of Figure 4, a data frame is a frame used for transmitting data to be forwarded to a higher layer, and may be transmitted after a backoff that occurs after a DIFS has elapsed since the medium became idle. Furthermore, a management frame is a frame used for exchanging management information that is not forwarded to a higher layer, and is transmitted after a backoff that occurs after an IFS, such as a DIFS or a PIFS (Point Coordination Function IFS). Subtype frames of management frames include a beacon, an association request / response, a re-association request / response, a probe request / response, and an authentication request / response. A control frame is a frame used to control access to a medium. Subtype frames of control frames include Request-To-Send (RTS), Clear-To-Send (CTS), Acknowledgment (ACK), Power Save-Poll (PS-Poll), BlockAck, BlockACKReq, NDP announcement (null data packet announcement), and Trigger. If a control frame is not a response frame of a previous frame, it is transmitted after a backoff that is performed after a DIFS has elapsed. If a control frame is a response frame of a previous frame, it is transmitted without a backoff after a short IFS (SIFS) has elapsed. The type and subtype of a frame may be identified by the type field and subtype field in the Frame Control (FC) field.

[0065] A Quality of Service (QoS) STA can transmit a frame after backing off after the arbitration IFS (AIFS) for the access category (AC) to which the frame belongs, i.e., AIFS[i] (where i is a value determined by the AC), has elapsed. Here, a frame that can use AIFS[i] can be a data frame, a management frame, or a control frame that is not a response frame.

[0066] FIG. 5 is a diagram for explaining a CSMA / CA base frame transmission operation to which the present disclosure can be applied.

[0067] As mentioned above, the CSMA / CA mechanism includes not only physical carrier sensing, in which a STA directly senses the medium, but also virtual carrier sensing. Virtual carrier sensing is intended to compensate for problems that may occur in medium access, such as the hidden node problem. For virtual carrier sensing, the MAC of a STA can use a network allocation vector (NAV). The NAV is a value that indicates to other STAs the time remaining until the medium becomes available for use by a STA currently using or authorized to use the medium. Therefore, the value set as the NAV corresponds to the period during which the STA transmitting the frame plans 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 MAC header of the frame.

[0068] In the example of Figure 5, 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.

[0069] In order to reduce the possibility of collisions between transmissions from multiple STAs in a CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames may be applied. In the example of FIG. 5, while STA1 is transmitting, STA3 may determine that the medium is idle as a result of carrier sensing. That is, STA1 may be a hidden node to STA3. Alternatively, in the example of FIG. 5, while STA2 is transmitting, STA3 may determine that the medium is idle as a result of carrier sensing. That is, STA2 may be a hidden node to STA3. By exchanging RTS / CTS frames before data transmission and reception between STA1 and STA2, STAs outside the transmission range of either STA1 or STA2, or outside the carrier sensing range for transmissions from STA1 or STA3, can be prevented from attempting to occupy the channel during data transmission and reception between STA1 and STA2.

[0070] Specifically, STA1 can determine whether a channel is occupied or not using carrier sensing. In terms of physical carrier sensing, STA1 can determine whether a channel is occupied or idle based on the energy magnitude or signal correlation detected from the channel. In terms of virtual carrier sensing, STA1 can determine whether a channel is occupied or idle using a network allocation vector (NAV) timer.

[0071] When the channel is idle in DIFS, STA1 can send an RTS frame to STA2 after backing off. When STA2 receives the RTS frame, it can send a CTS frame to STA1 as a response to the RTS frame after SIFS.

[0072] If STA3 cannot overhear the CTS frame from STA2 but can overhear the RTS frame from STA1, STA3 can use the duration information included in the RTS frame to set a NAV timer for the frame transmission period (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame) that will be transmitted subsequently. Alternatively, if STA3 cannot overhear the RTS frame from STA1 but can overhear the CTS frame from STA2, STA3 can use the duration information included in the CTS frame to set a NAV timer for the frame transmission period (e.g., SIFS + data frame + SIFS + ACK frame) that will be transmitted subsequently. That is, if STA3 can overhear one or more RTS or CTS frames from at least one of STA1 and STA2, it can set a NAV based thereon. If STA3 receives a new frame before the NAV timer expires, it can update the NAV timer using the duration information included in the new frame. STA3 does not attempt channel access until the NAV timer expires.

[0073] When STA1 receives a CTS frame from STA2, it can transmit a data frame to STA2 SIFS after the completion of reception of the CTS frame. When STA2 successfully receives a data frame, it can transmit an ACK frame, which is a response to the data frame, to STA1 SIFS after the completion of reception of the CTS frame. When STA2 successfully receives a data frame, it can transmit an ACK frame, which is a response to the data frame, to STA1 SIFS after the expiration of the NAV timer. When STA3 determines that the channel is not being used by another terminal during the DIFS period after the expiration of the NAV timer, it can attempt channel access after the contention window (CW) with random backoff has elapsed.

[0074] FIG. 6 is a diagram illustrating an example of a frame structure used in a wireless LAN system to which the present disclosure can be applied.

[0075] The PHY layer can prepare an MPDU (MAC PDU) to be transmitted based on an instruction or primitive (meaning a set of instructions or parameters) from the MAC layer. For example, when the PHY layer receives a command from the MAC layer requesting the start of PHY layer transmission, the PHY layer switches to transmission mode and transmits information (e.g., data) provided by the MAC layer in the form of a frame. In addition, when the PHY layer detects a valid preamble in a received frame, it monitors the preamble header and sends a command to the MAC layer informing the start of PHY layer reception.

[0076] Thus, information transmission / reception in a wireless LAN system is performed in the form of frames, for which a PHY layer protocol data unit (PPDU) format is defined.

[0077] A basic PPDU may include a Short Training Field (STF), a Long Training Field (LTF), a Signal (SIG) field, and a Data field. The most basic PPDU format (e.g., non-High Throughput (HT) shown in FIG. 7) may consist of only a Legacy-STF (L-STF), a Legacy-LTF (L-LTF), a SIG field, and a Data field. Depending on the type of PPDU format (e.g., HT-mixed format PPDU, HT-greenfield format PPDU, Very High Throughput (VHT) PPDU, etc.), an additional (or other type) RL-SIG, U-SIG, non-legacy SIG field, 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 described later with reference to FIG. 7.

[0078] The STF is a signal for signal detection, AGC (Automatic Gain Control), diversity selection, precise time synchronization, etc., and the LTF is a signal for channel estimation, frequency error estimation, etc. The STF and LTF can be said to be signals for synchronization and channel estimation of the OFDM physical layer.

[0079] The SIG field may contain various information related to the transmission and reception of the PPDU. For example, the L-SIG field may be composed of 24 bits and may include a 4-bit Rate field, a 1-bit Reserved field, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field. The Rate field may contain information regarding the modulation and coding rate of the data. For example, the 12-bit Length field may contain information regarding the length or time duration of the PPDU. For example, the value of the 12-bit Length field may be determined based on the type of PPDU. For example, for a non-HT, HT, VHT, or EHT PPDU, the value of the Length field may be determined as a multiple of 3. For example, for an HE PPDU, the value of the Length field may be determined as a multiple of 3 + 1 or a multiple of 3 + 2.

[0080] The data field may include a SERVICE field, a PSDU (Physical layer Service Data Unit), a PPDU TAIL bit, and, if necessary, padding bits. Some bits of the SERVICE field may be used for synchronization of a descrambler at the receiving end. The PSDU corresponds to a MAC PDU defined in the MAC layer and may contain data generated / used by a higher layer. The PPDU TAIL bit may be used to return the encoder to a 0 state. The padding bits may be used to adjust the length of the data field to a predetermined unit.

[0081] The MAC PDU is defined by various MAC frame formats, and a basic MAC frame consists of a MAC header, a frame body, and a Frame Check Sequence (FCS). The MAC frame is composed of the MAC PDU and may be transmitted / received by the PSDU in the data portion of the PPDU format.

[0082] The MAC header includes a Frame Control field, a Duration / ID field, an Address field, etc. The Frame Control field may include control information required for frame transmission / reception. The Duration / ID field may be set to the time for transmitting the frame, etc. The Address subfield may indicate the receiver address, transmitter address, destination address, or source address of the frame, and some address subfields may be omitted. For specific contents of each subfield of the MAC header, including the Sequence Control, QoS Control, and HT Control subfields, please refer to the IEEE 802.11 standard document.

[0083] The null data PPDU (NDP) format refers to a PPDU format that does not include a data field, i.e., NDP refers to a frame format that includes a PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields, and, if present, non-legacy SIG, non-legacy STF, and non-legacy LTF) in a general PPDU format, but does not include the remaining part (i.e., data field).

[0084] FIG. 7 is a diagram illustrating an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure is applicable.

[0085] Various types of PPDUs are used in standards such as IEEE 802.11a / g / n / ac / ax. The basic PPDU format (IEEE 802.11a / g) includes an L-LTF, an L-STF, an L-SIG, and a Data field. The basic PPDU format can also be called a non-HT PPDU format (see FIG. 7(a)).

[0086] The HT PPDU format (IEEE 802.11n) further includes 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 an HT-mixed format. An HT-greenfield format PPDU may also be defined, which corresponds to a format that does not include L-STF, L-LTF, or L-SIG, but is composed of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a Data field (not shown).

[0087] An example of a VHT PPDU format (IEEE 802.11ac) further includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in addition to the basic PPDU format (FIG. 7(c)).

[0088] An example of the HE PPDU format (IEEE 802.11ax) further includes the fields Repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), and Packet Extension (PE) in addition to the basic PPDU format (FIG. 7(d)). Depending on the detailed example of the HE PPDU format, some fields may be excluded or their lengths may vary. For example, the HE-SIG-B field is included in the HE PPDU format for 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 the HE-SIG-B, and the length of the HE-STF field may be changed to microseconds (us). The HE Extended Range (ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may be changed to 16 us. For example, the RL-SIG may be configured to be the same as the L-SIG. Based on the presence of the RL-SIG, the receiving STA can determine whether the received PPDU is an HE PPDU or an EHT PPDU (described later).

[0089] The EHT PPDU format may include the EHT MU (multi-user) PPDU in Figure 7(e) and the EHT TB (trigger-based) PPDU in Figure 7(f). The EHT PPDU format is similar to the HE PPDU format in that it includes an L-SIG followed by an RL-SIG, but may also include a U (universal)-SIG, EHT-SIG, EHT-STF, and EHT-LTF following the RL-SIG.

[0090] The EHT MU PPDU in Figure 7(e) corresponds to a PPDU that carries one or more data (or PSDUs) for one or more users. That is, the EHT MU PPDU may be used for both SU transmission and MU transmission. For example, the EHT MU PPDU may correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0091] The EHT TB PPDU in Figure 7(f) omits the EHT-SIG compared to the EHT MU PPDU. A 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.

[0092] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal Signal), and EHT-SIG fields may be encoded and modulated and mapped based on a predetermined subcarrier frequency interval (e.g., 312.5 kHz) so that legacy STAs can also attempt demodulation and decoding. 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 and mapped based on a predetermined subcarrier frequency interval (e.g., 78.125 kHz) so that they can be demodulated and decoded by STAs that successfully decode non-legacy SIGs (e.g., U-SIG and / or EHT-SIG) and obtain the information contained in these fields. These may be referred to as EHT modulated fields.

[0093] 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 free HE modulation fields, and the HE-STF, HE-LTF, Data, and PE fields can be referred to as HE modulation fields. Also, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be referred to as free VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields can be referred to as VHT modulation fields.

[0094] The U-SIG included in the EHT PPDU format of Fig. 7 may be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG may have a duration of 4 us, and the entire U-SIG may have a duration of 8 us. 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.

[0095] U-SIGs may be configured in 20 MHz units. For example, when an 80 MHz PPDU is configured, the same U-SIG may be duplicated in 20 MHz units. That is, four identical U-SIGs may be included in an 80 MHz PPDU. When the bandwidth exceeds 80 MHz, for example, for a 160 MHz PPDU, the first U-SIG in the 80 MHz unit and the second U-SIG in the 80 MHz unit may be different from each other.

[0096] For example, a U-SIG may transmit A uncoded bits, with the first symbol of the U-SIG (e.g., U-SIG-1 symbol) transmitting the first X bits of the total A bits of information, and the second symbol of the U-SIG (e.g., U-SIG-2 symbol) transmitting the remaining Y bits of information of the total A bits of information. The A bits of information (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 a convolutional decoder and may be set to 0, for example.

[0097] The A-bit information transmitted by the U-SIG may be divided into version-independent bits and version-dependent bits. For example, the U-SIG may be included in a new PPDU format (e.g., a UHR PPDU format) not shown in FIG. 7. In the format of the U-SIG field included in the EHT PPDU format and the format of the U-SIG field included in the UHR PPDU format, the version-independent bits may be the same, but some or all of the version-dependent bits may be different.

[0098] For example, the size of the version-independent bits in a U-SIG may be fixed or variable. The version-independent bits may be assigned only to the U-SIG-1 symbol or to both the U-SIG-1 and U-SIG-2 symbols. The version-independent bits and version-dependent bits may be referred to by various names, such as first control bits and second control bits.

[0099] For example, the version independent bits of the U-SIG may include a 3-bit PHY version identifier, which may indicate the PHY version (e.g., EHT, UHR, etc.) of the transmitted and received PPDU. The version independent bits of the U-SIG may include a 1-bit UL / DL flag field. A first value of the 1-bit UL / DL flag field is associated with UL communication, and a second value of the UL / DL flag field is associated with DL communication. The version independent bits of the U-SIG may include information regarding the length of a transmission opportunity (TXOP) and information regarding a BSS color ID.

[0100] For example, the version dependent bits of the U-SIG may contain information that directly or indirectly indicates the type of PPDU (eg, SU PPDU, MU PPDU, TB PPDU, etc.).

[0101] Information necessary for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may further include information about the bandwidth, information about the MCS scheme applied to the non-legacy SIG (e.g., EHT-SIG or UHR-SIG), information indicating whether a dual carrier modulation (DCM) scheme (e.g., a scheme for achieving an effect similar to frequency diversity by reusing the same signal on two subcarriers) is applied to the non-legacy SIG, information about the number of symbols used for the non-legacy SIG, information about whether the non-legacy SIG is generated across the entire band, etc.

[0102] Some of the information necessary for PPDU transmission and reception may be included in the U-SIG and / or non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.). For example, information on the type of non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information on the length of the non-legacy LTF and the cyclic prefix (CP) length, information on the guard interval (GI) applied to the non-legacy LTF, information on preamble puncturing applicable to the PPDU, information on resource unit (RU) allocation, etc. may be included only in the U-SIG, or only in the non-legacy SIG, or may be indicated by a combination of information included in the U-SIG and information included in the non-legacy SIG.

[0103] Preamble puncturing may refer to the transmission of a PPDU in which no signal is present in one or more frequency units of the PPDU bandwidth. For example, the size of the frequency unit (or the resolution of the preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to PPDU bandwidths equal to or larger than a predetermined size.

[0104] In the example of Figure 7, non-legacy SIGs such as HE-SIG-B and EHT-SIG may contain control information for the receiving STA. The non-legacy SIGs may be transmitted in at least one symbol, and one symbol may have a length of 4us. Information regarding the number of symbols used for the EHT-SIG may be included in previous SIGs (e.g., HE-SIG-A, U-SIG, etc.).

[0105] Non-legacy SIGs such as HE-SIG-B and EHT-SIG may include common fields and user-specific fields, which may be coded separately.

[0106] 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 may receive the PPDU (e.g., the data field of the PPDU) in the same frequency band. In an uncompressed mode where OFDMA is applied, multiple users may receive the PPDU (e.g., the data field of the PPDU) in different frequency bands.

[0107] The number of user-specific fields may be determined based on the number of users. One user block field may include up to two user fields. Each user field may be associated with a MU-MIMO allocation or a non-MU-MIMO allocation.

[0108] The common field may include CRC bits and tail bits, where the length of the CRC bits may be determined to be 4 bits, and the length of the tail bits may be determined to be 6 bits and set to 000000. The common field may include RU allocation information. The RU allocation information may include information about the locations of RUs to which multiple users (i.e., multiple receiving STAs) are allocated.

[0109] An RU may include multiple subcarriers (or tones). An RU may be used when transmitting signals to multiple STAs based on OFDMA techniques. An RU may also be defined when transmitting a signal to a single STA. Resources may be allocated in RU units for the non-legacy STF, non-legacy LTF, and Data field.

[0110] Applicable RU sizes may be defined depending on the PPDU bandwidth. RUs may be defined to be the same or different for applicable PPDU formats (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80 MHz PPDU, the RU arrangements for HE PPDU and EHT PPDU may be different from each other. The applicable RU size, number of RUs, RU locations, DC (direct current) subcarrier locations and numbers, null subcarrier locations and numbers, and guard subcarrier locations and numbers for each PPDU bandwidth may be referred to as a tone plan. For example, a tone plan for a wide bandwidth may be defined as multiple repetitions of a tone plan for a low bandwidth.

[0111] 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 consisting 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 one MRU may be contiguous or non-contiguous in the frequency domain.

[0112] The specific size of an RU may be reduced or expanded. Therefore, the specific size of each RU (i.e., the corresponding number of tones) in this disclosure is not limited and is merely exemplary. 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 RU size.

[0113] The names of the fields in the PPDU format of Fig. 7 are merely examples, and the scope of the present disclosure is not limited by the names. In addition, the examples of the present disclosure may be applied not only to the PPDU format illustrated in Fig. 7, but also to a new PPDU format in which some fields are omitted and / or some fields are added based on the PPDU format of Fig. 7.

[0114] quality of service characteristics element

[0115] The QoS characteristic elements defined in a wireless LAN system include a set of parameters that define traffic flow characteristics and QoS expectations. In this regard, in the context of a specific non-AP EHT STA, the QoS characteristic elements are used by the EHT AP and non-AP EHT STAs to support QoS traffic transfer using a stream classification service (SCS) procedure and a restricted TWT procedure.

[0116] FIG. 8 illustrates QoS characteristic elements applicable to embodiments of the present disclosure.

[0117] Specifically, the control information field includes a direction subfield, a traffic ID (TID) subfield, a user priority (UP) subfield, a presence bitmap of additional parameters subfield, a link ID subfield, and reserved bits (e.g., 3 bits).

[0118] The direction subfield specifies the direction of the data described by the element and indicates uplink, downlink, direct link, or reserved, where uplink means that MSDU(s) or A-MSDU(s) are transmitted from a non-AP STA to an AP, downlink means that MSDU(s) or A-MSDU(s) are transmitted from an AP to a non-AP STA, and direct link means that MSDU(s) or A-MSDU(s) are transmitted via a peer-to-peer (P2P) link.

[0119] The TID subfield contains the TID value of the data frame described by this element. The TID subfield is set to the same value as the UP subfield. Here, TID subfield values ​​8 through 15 are reserved. In this regard, the existence of the TID subfield may be for future expansion so that TID values ​​independent of user priority (UP) can be transmitted.

[0120] The UP subfield contains the UP value (any one of 0 to 7) of the data frame described by this element. If a TCLAS (traffic classification) element is present in the SCS request frame containing this element, the UP subfield is set to the UP value specified in the TCLAS element.

[0121] The Presence Bitmap Of Additional Parameters subfield contains a bitmap in which the i-th entry of the bitmap is set to 1 if the i-th field, starting from the Maximum MSDU Size field, is present in the element. The value 0 is reserved for each field, starting from the Maximum MSDU Size field.

[0122] The Link ID subfield contains the link identifier corresponding to the link through which the direct link transmission occurs. If the Direction subfield is equal to any value other than the value indicating the direct link, this subfield is reserved.

[0123] The Minimum Service Interval field contains an unsigned integer that specifies the minimum interval (e.g., in milliseconds (ms)) between two consecutive service periods (SPs) that are assigned frame exchanges (e.g., UL / DL / direct link based frame exchanges). The Maximum Service Interval field contains an unsigned integer that specifies the maximum interval (e.g., in ms) between two consecutive service periods (SPs) that are assigned frame exchanges (e.g., UL / DL / direct link based frame exchanges). In this regard, the value of the Maximum Service Interval field is greater than or equal to the value of the Minimum Service Interval field.

[0124] The Minimum Data Rate field contains an unsigned integer that specifies the minimum data rate (e.g., kilobits per second) specified in the MAC SAP for the transmission of MSDU(s) or A-MSDU(s) belonging to the traffic flow described by this element.

[0125] The delay bound field contains an unsigned integer that specifies the maximum time (e.g., in micro-seconds) allowed for transmitting MSDU(s) or A-MSDU(s) belonging to the traffic flow described by this element.

[0126] The Maximum MSDU Size field contains an unsigned integer that specifies the maximum size (in octets) of the MSDU(s) or A MSDU(s) that belong to the traffic flow described by this element.

[0127] The Service Start Time field contains an unsigned integer that specifies the anticipated time (e.g., in microseconds) when traffic will begin for the associated TID. Here, the Service Start Time indicates to the AP when the STA is expected to exchange frames corresponding to the TID specified in this element. This field indicates the lowest four octets of the TSF timer associated with the link specified in the Link ID field at the anticipated SP start time.

[0128] The four least significant bits (LSBs) of the Service Start Time Link ID field indicate the link identifier corresponding to the link for which the TSF timer is used to indicate the service start time. The four most significant bits (MSBs) are reserved. This field is present only if the Service Start Time field is present.

[0129] The Mean Data Rate field indicates the mean data rate (e.g., in kilobits per second) specified in the MAC SAP for the transmission of MSDU(s) or A-MSDU(s) belonging to the traffic flow within the bounds of the element.

[0130] The Burst Size field is 4 octets in length and contains an unsigned integer that specifies the largest burst (e.g., in octets) of MSDU(s) or A-MSDU(s) belonging to a traffic flow that arrives at the MAC SAP within the time specified in the Delay Bound field.

[0131] The MSDU Lifetime field contains an unsigned integer that specifies the maximum time (e.g., in milliseconds) after an MSDU arrives at the MAC Data Service Interface, beyond which the MSDU is no longer useful to the receiver. Thus, an MSDU transmitter can consider discarding such an MSDU at the transmitter before it is transmitted over the air. The time specified in this field is greater than or equal to the time specified in the Delay Bound field (if present).

[0132] The MSDU Delivery Info field contains MSDU delivery information. The MSDU Delivery Info field includes an MSDU Delivery Ratio subfield and an MSDU Count Exponent subfield. Here, the MSDU Delivery Ratio subfield specifies the MSDU loss requirement (e.g., 95% to 99.9999%). The MSDU Count Exponent subfield contains an unsigned integer that specifies an exponent for the number of received MSDUs used to calculate the MSDU delivery ratio. In this case, the number of received MSDUs is equal to 10 MSDU Count Exponents. If no delay bound is specified, the MSDU Delivery Info subfield is not present.

[0133] Stream Classification Service Procedures

[0134] The present disclosure relates to a scheme for directing links for low latency traffic based on SCS procedures.

[0135] The SCS procedure, i.e., the SCS negotiation procedure, may be performed based on the exchange of an SCS request frame and an SCS response frame.

[0136] For example, the STA may include stream classification-related information and / or low-latency traffic transmission request conditions in an SCS Descriptor element within an SCS Request frame and transmit it to the AP. In this case, one or more SCS Descriptor elements may be present in the frame, and each SCS Descriptor element may be distinguished by an SCS ID. The AP may transmit an SCS Response frame to the STA, including a status code and / or an SCS Descriptor element for the received SCS ID, thereby completing the SCS negotiation.

[0137] Specifically, when utilizing SCS, layer 2 and / or layer 3 signaling can be used to establish a classification that matches an individually addressed MSDU. Once classified, the individually addressed MSDU that matches the classification is assigned to an access category (AC) and assigned a drop eligibility tag. When intra-access category prioritization is activated, SCS can be used to assign MSDUs that match the classification to a primary or alternate enhanced distributed channel access (EDCA) transmit queue, applying more granular prioritization.

[0138] Specifically, an SCS request frame is used to request the creation, modification, and / or deletion of stream classifications using procedures defined in the SCS procedures, where the action field format of the SCS request frame may include a one-octet category field, a one-octet robust action field, a one-octet dialog token field, and / or a variable SCS descriptor list field containing one or more SCS descriptor elements.

[0139] An SCS response frame is transmitted in response to an SCS request frame using procedures defined in the SCS procedures, where the action field format of the SCS response frame may include a one-octet category field, a one-octet robust action field, a one-octet dialog token field, a variable SCS status list field containing one or more SCS status duples, and / or a variable SCS descriptor list field containing one or more SCS descriptor elements.

[0140] Here, the SCS status duple format may include an SCS ID field indicating an SCS stream and a status field indicating the status (i.e., status code) of the SCS stream.

[0141] Furthermore, in relation to an SCS Response frame, an SCS Descriptor List may be optionally present when the SCS Response frame is transmitted from a STA affiliated with a multi-link device (MLD) to a STA affiliated with another MLD. If present, it may contain zero or more SCS Descriptor elements. Here, each SCS Descriptor element may contain a QoS characteristics element that describes the traffic characteristics and QoS expectations of the traffic flow belonging to the SCS stream identified by the SCS ID field value of the same SCS Descriptor element. Specifically, if the Status Code field value of the SCS ID is "SUCCESS" or "REJECTED_WITH_SUGGESTED_CHANGES," zero or one SCS Descriptor element may be present in the SCS Status List field; otherwise, no SCS Descriptor element may be present.

[0142] The SCS descriptor element that may be included in the above-described SCS request / response frame defines information about streams classified by the SCS procedure and may be configured as shown in FIG.

[0143] FIG. 9 illustrates an example of an SCS descriptor element applicable to an embodiment of the present disclosure.

[0144] Referring to FIG. 9, the SCS descriptor element may include an Element ID field, a Length field, an SCS ID field, a Request Type field, an Intra-Access Category Priority Element field (optional), a TCLAS (Traffic Classification) element field (optional), a TCLAS processing element field (optional), a QoS characteristic element field (optional) (e.g., see the QoS characteristic element in FIG. 8), and optional subelements fields.

[0145] Here, the SCS ID field is set to a non-zero value selected by a non-AP STA that identifies the SCS stream specified in the SCS descriptor element.

[0146] The request type field is set to a number to identify the type of SCS request. For example, the value 0 indicates "Add", the value 1 indicates "Remove", the value 2 indicates "Change", and the values ​​3 to 255 are reserved. The intra-access category priority element field exists when the request type field is "Add" or "Change".

[0147] The TCLAS element field contains zero or more TCLAS elements that specify how the received MSDU is classified as part of the corresponding SCS stream. One or more TCLAS elements are present when the Request Type field is 'Add' or 'Change', and no TCLAS elements are present when the Request Type field is 'Remove'. The TCLAS Processing element field is present when there are two or more TCLAS elements in the TCLAS element field, and contains a TCLAS Processing element that defines how the multiple TCLAS elements are processed.

[0148] Link indication method for low-delay traffic based on SCS procedure

[0149] The present disclosure relates to a scheme for indicating / configuring information regarding one or more links for transmitting and receiving low latency traffic / data within an SCS procedure.

[0150] With reference to existing SCS procedures and QoS characteristic elements (e.g., IEEE 802.11 / 802.11be, etc.), only a Link ID subfield exists in the control field of the QoS characteristic element related to information regarding the link over which low latency traffic / data is transmitted and received within the SCS request / response frame.

[0151] However, as described above, the link ID subfield is defined to indicate the link ID of the link through which low latency traffic is transmitted and received when the value of the Direction subfield in the control field of the same QoS characteristic element is a direct link (i.e., Peer-to-Peer, P2P). Here, the link ID subfield has a length of 4 bits and can indicate one link.

[0152] In consideration of this, the existing link ID subfield may be extended and defined to indicate information (e.g., link ID) about the link through which low latency traffic based on the UL direction and / or DL ​​direction is transmitted and received, but even in this case, there is a limit where only one link can be indicated.

[0153] Therefore, the present disclosure provides specific examples of an SCS negotiation procedure, i.e., a method for indicating one or more links over which low latency traffic / data is transmitted and received within an SCS request / response frame.

[0154] Specifically, information related to the link may be defined / utilized by being included in an SCS request / response frame based on one or more of the following embodiments.

[0155] The values / names described in the embodiments of the present disclosure do not limit the scope of the present disclosure and can be changed / substituted with other values / names, etc. Furthermore, in the embodiments of the present disclosure, the STAs may include non-AP STAs and AP STAs.

[0156] Example 1

[0157] This embodiment relates to a method of including a link information element containing information indicating one or more links in an SCS request / response frame to indicate information on links to be used for transmitting and receiving low-latency traffic / data.

[0158] The link information element may be defined to include bitmap information for indicating link IDs of one or more links (ie, link ID bitmap information).

[0159] For example, the link information element may be configured based on the MLO link information element format as shown in Fig. 10. In this embodiment, the structure of the link information element will be described using the MLO link information element format as an example, but the scope of the present disclosure is not limited to this and may be replaced / extended to one based on another information element format including bitmap information for indicating the link ID.

[0160] FIG. 10 illustrates an example of an MLO link information element according to an embodiment of the present disclosure.

[0161] Referring to FIG. 10, the MLO link information element format may include an Element ID field, a Length field, an Element ID Extension field, and a Link ID Bitmap field.

[0162] The MLO Link Information Element is defined to indicate information about the link that a STA in an MLD operates to send and receive messages to a peer MLD. In this regard, by setting the bit corresponding to the link ID in the Link ID Bitmap field to 1, the STA can share information about the link that it operates with the peer MLD.

[0163] Specifically, the link information element proposed in this disclosure may be included in the SCS descriptor element (e.g., see the SCS descriptor element in Figure 9) in the SCS request / response frame to indicate information about the link used for transmitting and receiving low-latency traffic / data.

[0164] FIG. 11 illustrates an example of an SCS descriptor element including a link information element according to an embodiment of the present disclosure.

[0165] Referring to FIG. 11, a link information element may be included within an SCS descriptor element in an SCS request / response frame and may be defined to indicate one or more links associated with the traffic / data based on the SCS descriptor element.

[0166] Although Fig. 11 shows that the link information element is located after the QoS characteristic element, the position at which the link information element is added within the SCS descriptor element is not limited to the example shown in Fig. 11. Furthermore, the link information element may be defined to be selectively included only when instructions for one or more links are required, and may be defined to have a length of 0 to 5 octets.

[0167] For example, a link information element included within an SCS descriptor element in an SCS request / response frame may indicate one or more links that support transmission / reception of traffic / data having characteristics indicated by an Intra-Access Category Priority Element, a TCLAS element, and / or a QoS characteristic element.

[0168] As a specific example, when the QoS characteristic element and the link information element are both included in the SCS descriptor element, this may mean that they indicate / include information about a link that supports the transmission and reception of low latency traffic / data.

[0169] An existing MLO link information element (e.g., the MLO link information element defined in the IEEE 802.11be standard) is defined to have a value of 1 for only one link. For example, when there are three links (e.g., link 1, link 2, and link 3), if link 1 cannot transmit a message on link 3, the link information element may indicate which link's information is transmitted instead of the link 1. As a specific example, if link 3 is 'busy' or in a doze state in power saving (PS) mode, a target wake time (TWT) frame may be transmitted on link 1 instead of link 3. In this case, the link ID bitmap in the MLO link information element is set to indicate link 3 and transmitted, and a STA receiving the MLO link information element can recognize that the TWT frame is a TWT frame for link 3.

[0170] In contrast, the link information element (e.g., MLO link information element) in the SCS request / response frame in the present disclosure is defined so that it can have a value of 1 for one or more links (i.e., so that any one or more of the multiple bits constituting the bitmap information can be set to the value 1). That is, the existing SCS procedure does not separately configure / indicate links because it is applied to the MLD level, i.e., it is commonly applied to all links belonging to the MLD. In contrast, the method proposed in the present disclosure enables link-level indication even in the SCS procedure, thereby providing a technical effect of enabling efficient transmission and reception of low-latency traffic / data using flexible / adaptive link utilization.

[0171] Example 2

[0172] This embodiment relates to a method of including a field indicating one or more links in a QoS characteristic element in an SCS request / response frame to indicate information about links to be used for transmitting and receiving low latency traffic / data.

[0173] FIG. 12 illustrates an example QoS characteristic element including a Link ID Bitmap field according to an embodiment of the present disclosure.

[0174] Referring to FIG. 12, a field for indicating one or more links may be newly added / defined to a QoS characteristic element that may be included in an SCS descriptor element in an SCS request / response frame.

[0175] Here, the new field may be referred to as a link ID bitmap field, and one or more bits constituting the bitmap information may be used to indicate whether a corresponding link supports an operation. That is, when the value of the bit is set to "1," it may mean that the link of the link ID corresponding to the bit supports the operation.

[0176] In FIG. 12, it is assumed that the location of the Link ID Bitmap field is after the Delay Bound field in the QoS characteristic element, but this location is an example and is not limited to this.

[0177] Furthermore, although FIG. 12 shows that the length of the link ID bitmap field is 2 octets (i.e., 16 bits), this is not limited to this, and the length of the link ID bitmap field may be variably set / defined depending on the maximum number of links that can be supported.

[0178] The method of adding a new link ID bitmap field to the QoS characteristic element in this embodiment may affect the size of the QoS characteristic element, but the method in this embodiment requires less overhead than the method of adding a link information element (e.g., a 5-octet MLO link information element / field) described in the previous embodiment (i.e., embodiment 1).

[0179] In relation to the embodiments of the present disclosure, the method is described using a case where it is applied to low-latency traffic as a representative example, but it is not excluded that the method may be extended and applied to other types of traffic.

[0180] The operation of the STA according to the embodiment of the present disclosure will be described below with reference to FIGS.

[0181] 13 and 14 may correspond to some of various examples of the present disclosure. For example, in FIG. 13 and 14, the first STA may correspond to a non-AP STA, and the second STA may correspond to an AP.

[0182] FIG. 13 is a flowchart illustrating an operation by a first STA according to an embodiment of the present disclosure.

[0183] Referring to FIG. 13, a first STA may transmit a stream classification service (SCS) request frame including information related to negotiation of a particular type of traffic to a second STA (S1310).

[0184] For example, the particular type of traffic may correspond to low-latency traffic transmitted between a first STA and a second STA.

[0185] In this regard, the specific type of traffic may be based on either uplink traffic or downlink traffic between the first STA and the second STA. Additionally or alternatively, the specific type of traffic may correspond to traffic for direct link transmission (e.g., P2P transmission) between the first STA and the second STA.

[0186] Thereafter, the first STA may receive an SCS response frame from the second STA in response to the SCS request frame (S1320).

[0187] In this regard, at least one of the SCS request frame or the SCS response frame may include link-related information indicating one or more links over which the particular type of traffic is transmitted or received.

[0188] For example, the link-related information may be defined based on a bitmap format consisting of one or more bits for indicating whether or not one or more links are supported, and in this regard, the one or more bits may be mapped to different link identifiers (Link IDs).

[0189] In this regard, the link-related information may be in an information element format and may be defined to be included in an SCS descriptor element (see, for example, FIG. 11). For example, a specific type of traffic may correspond to traffic based on one or more information elements in the SCS descriptor element, and the one or more information elements may include at least one of an intra-access category priority element, a traffic classification (TCLAS) element, or a QoS characteristics element. In this case, the link-related information may be defined to be located following the QoS characteristics element in the SCS descriptor element.

[0190] Additionally or alternatively, the link-related information may be in a field format and defined to be included in the QoS characteristic element (see, for example, FIG. 12). For example, the link-related information may be defined to be located after a Delay Bound field in the QoS characteristic element.

[0191] The method performed by the first STA described in the example of Figure 13 may be performed by the first device 100 of Figure 1. For example, one or more processors 102 of the first device 100 of Figure 1 may be configured to transmit an SCS request frame to the second STA 200 and receive an SCS response frame from the second STA 200 via one or more transceivers 106 in association with an indication of link-related information indicating one or more links over which a particular type of traffic is transmitted or received. Additionally, one or more memories 104 of the first device 100 may store instructions for performing the method described in the example of Figure 13 or the previous examples when executed by the one or more processors 102.

[0192] FIG. 14 is a flowchart illustrating an operation by the second STA according to an embodiment of the present disclosure.

[0193] Referring to FIG. 14, a second STA may receive a stream classification service (SCS) request frame from a first STA, the stream classification service request frame including information related to negotiation of a particular type of traffic (S1410).

[0194] The details regarding specific types of traffic in FIG. 14 overlap with the details explained in FIG. 13, so a detailed explanation thereof will be omitted.

[0195] Thereafter, the second STA may transmit an SCS response frame to the first STA in response to the SCS request frame (S1420).

[0196] In this regard, at least one of the SCS request frame or the SCS response frame may include link-related information indicating one or more links over which the particular type of traffic is transmitted or received.

[0197] The details regarding the SCS request frame, SCS response frame, and link-related information in FIG. 14 are the same as those described in FIG. 13, so a detailed description thereof will be omitted.

[0198] The method performed by the second STA described in the example of Figure 14 may be performed by the second device 200 of Figure 1. For example, one or more processors 202 of the second device 200 of Figure 1 may be configured to receive an SCS request frame from the first STA 100 and transmit an SCS response frame to the first STA 100 via one or more transceivers 206 in association with an indication of link-related information indicating one or more links over which a particular type of traffic is transmitted or received. Additionally, one or more memories 204 of the second device 200 may store instructions for performing the method described in the example of Figure 14 or the previous examples when executed by the one or more processors 202.

[0199] In existing WLAN systems, link information in the SCS procedure relates only to direct links between STAs (e.g., P2P operations), and only one link can be indicated. In contrast, the method proposed in this disclosure can indicate one or more links for each traffic negotiated in the SCS procedure, achieving a new effect of indicating link information for uplink (UL) and / or downlink (DL)-based traffic.

[0200] 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 stated. Each component or feature may be implemented without being combined with other components or features. It is also possible to combine some components and / or features to form embodiments of the present disclosure. The order of operations described in the embodiments of the present disclosure may be changed. Some components or features of one embodiment may be included in another embodiment, or may be replaced with corresponding components or features of another embodiment. It is clear that claims that do not have an explicit reference relationship in the claims may be combined to form embodiments, or may be included as new claims by amendment after filing.

[0201] It is obvious to those skilled in the art that the present disclosure can be embodied in other specific forms without departing from the essential features of the present disclosure. Therefore, the above detailed description should not be interpreted as limiting in any respect, but should be considered as illustrative. The scope of the present disclosure should be determined by reasonable interpretation of the appended claims, and any modifications within the equivalent scope of the present disclosure are included in the scope of the present disclosure.

[0202] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that cause a device or computer to perform operations according to the methods of various embodiments, as well as non-transitory computer-readable media on which such software or instructions are stored and executable on a device or computer. Instructions usable for programming a processing system to perform features described in this disclosure may be stored on or in a storage medium or computer-readable storage medium, and computer program products including such storage media may be used to embody features described in this disclosure. Storage media may include high-speed random access memory such as DRAM, SRAM, DDR RAM, or other random access solid-state memory devices, but may also 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, comprise non-transitory computer-readable storage media. The features described in this disclosure may be embodied in software and / or firmware stored on any one of a number of machine-readable media and capable of controlling the hardware of a processing system and allowing the processing system to interact with other mechanisms that utilize the results of embodiments of the present disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0203] [Industrial Applicability] The method proposed in this disclosure has been described mainly as being applied to an IEEE 802.11-based system, but it can also be applied to various wireless LANs or wireless communication systems other than the IEEE 802.11-based system.

[0204] [Claims at the time of international application] [Claim 1] A method performed by a first station (STA) in a wireless LAN system, comprising: transmitting, to a second STA, a stream classification service (SCS) request frame including information related to negotiation of a particular type of traffic; receiving an SCS response frame from the second STA in response to the SCS request frame; At least one of the SCS request frame or the SCS response frame includes link-related information indicating one or more links over which the particular type of traffic is transmitted or received. [Claim 2] The method of claim 1 , wherein the link-related information is defined based on a bitmap format configured with one or more bits for indicating whether or not the one or more links are supported. [Claim 3] The method of claim 2 , wherein the one or more bits are mapped to different link identifiers (Link IDs). [Claim 4] The method of claim 1, wherein the specific type of traffic is based on either uplink traffic or downlink traffic between the first STA and the second STA. [Claim 5] The method of claim 1, wherein the specific type of traffic corresponds to low-latency traffic transmitted and received between the first STA and the second STA. [Claim 6] The method of claim 1 , wherein the link-related information is in an information element format and is defined to be included in an SCS descriptor element. [Claim 7] The specific type of traffic corresponds to traffic based on one or more information elements in the SCS descriptor element, 7. The method of claim 6, wherein the one or more information elements include at least one of an intra-access category priority element, a traffic classification (TCLAS) element, or a QoS characteristics element. [Claim 8] The method of claim 6 , wherein the link-related information is defined to be located following a QoS characteristic element within the SCS descriptor element. [Claim 9] The method of claim 1 , wherein the link-related information is in a field format and is defined to be included in a QoS characteristic element. [Claim 10] The method of claim 9, wherein the link-related information is defined to be located after a delay bound field within the QoS characteristic element. [Claim 11] The method of claim 1 , wherein the first STA corresponds to a non-AP (non-access point) STA, and the second STA corresponds to an AP. [Claim 12] A first station (STA) device in a wireless LAN system, one or more transceivers; one or more processors coupled to the one or more transceivers; the one or more processors: transmitting to a second STA a stream classification service (SCS) request frame containing information related to negotiation of a particular type of traffic; receiving an SCS response frame from the second STA in response to the SCS request frame; At least one of the SCS request frame or the SCS response frame includes link-related information indicating one or more links over which the particular type of traffic is transmitted or received. [Claim 13] A method performed by a second station (STA) in a wireless LAN system, comprising: receiving a stream classification service (SCS) request frame from a first STA, the request frame including information related to negotiation of a particular type of traffic; transmitting an SCS response frame to the first STA in response to the SCS request frame; At least one of the SCS request frame or the SCS response frame includes link-related information indicating one or more links over which the particular type of traffic is transmitted or received. [Claim 14] A second station (STA) device in a wireless LAN system, one or more transceivers; one or more processors coupled to the one or more transceivers; the one or more processors: receiving a stream classification service (SCS) request frame from a first STA, the stream classification service request frame including information related to negotiation of a particular type of traffic; Configuring the first STA to transmit an SCS response frame in response to the SCS request frame; At least one of the SCS request frame or the SCS response frame includes link-related information indicating one or more links over which the particular type of traffic is transmitted or received. [Claim 15] 1. A processing unit configured to control a station (STA) in a wireless LAN system, comprising: one or more processors; and one or more computer memories operably coupled to the one or more processors and storing instructions for performing the method of any one of claims 1 to 11 when executed by the one or more processors. [Claim 16] one or more non-transitory computer-readable media storing one or more instructions, A computer-readable medium, wherein the one or more instructions are executed by one or more processors to control a station (STA) device in a wireless LAN system to perform the method according to any one of claims 1 to 11.

Claims

1. A method performed by a first station (STA) in a wireless LAN system, comprising: transmitting a stream classification service (SCS) request frame including information related to negotiation of a particular type of traffic to a second STA; receiving an SCS response frame from the second STA in response to the SCS request frame; At least one of the SCS request frame or the SCS response frame includes link-related information indicating one or more links over which the particular type of traffic is transmitted or received.

2. The method according to claim 1 , wherein the link-related information is defined based on a bitmap format configured with one or more bits for indicating whether or not the one or more links are supported.

3. The method of claim 2 , wherein the one or more bits are mapped to different link identifiers (Link IDs).

4. The method of claim 1 , wherein the specific type of traffic is based on either uplink traffic or downlink traffic between the first STA and the second STA.

5. The method of claim 1, wherein the specific type of traffic corresponds to low-latency traffic transmitted and received between the first STA and the second STA.

6. The method of claim 1, wherein the link-related information is in an information element format and is defined to be included in an SCS descriptor element.

7. The specific type of traffic corresponds to traffic based on one or more information elements in the SCS descriptor element, 7. The method of claim 6, wherein the one or more information elements include at least one of an intra-access category priority element, a traffic classification (TCLAS) element, or a QoS characteristics element.

8. The method of claim 6 , wherein the link-related information is defined to be located following a QoS characteristic element within the SCS descriptor element.

9. The method of claim 1 , wherein the link-related information is in a field format and is defined to be included in a QoS characteristic element.

10. The method of claim 9 , wherein the link-related information is defined to be located after a Delay Bound field within the QoS characteristic element.

11. The method of claim 1, wherein the first STA corresponds to a non-access point (non-AP) STA and the second STA corresponds to an AP.

12. A first station (STA) device in a wireless LAN system, one or more transceivers; one or more processors coupled to the one or more transceivers; The one or more processors: Sending a stream classification service (SCS) request frame to a second STA, the stream classification service request frame including information related to negotiation of a particular type of traffic; receiving an SCS response frame from the second STA in response to the SCS request frame; At least one of the SCS request frame or the SCS response frame includes link-related information indicating one or more links over which the particular type of traffic is transmitted or received.

13. A method performed by a second station (STA) in a wireless LAN system, comprising: receiving a stream classification service (SCS) request frame from a first STA, the request frame including information related to negotiation of a particular type of traffic; transmitting an SCS response frame to the first STA in response to the SCS request frame; At least one of the SCS request frame or the SCS response frame includes link-related information indicating one or more links over which the particular type of traffic is transmitted or received.

14. A second station (STA) device in a wireless LAN system, one or more transceivers; one or more processors coupled to the one or more transceivers; The one or more processors: Receive a stream classification service (SCS) request frame from a first STA, the request frame including information related to negotiation of a particular type of traffic; transmitting an SCS response frame to the first STA in response to the SCS request frame; At least one of the SCS request frame or the SCS response frame includes link-related information indicating one or more links over which the particular type of traffic is transmitted or received.

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

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

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