Method and apparatus for performing operation based on TID-to-link mapping in a wireless LAN system

Abstract

A method and apparatus operating in a wireless LAN system are disclosed. A method performed by a first STA MLD in a wireless LAN system according to an embodiment of the present disclosure includes transmitting a specific element including a multi-user (MU) EDCA (enhanced distributed channel access) mapping field to a second STA MLD or receiving the specific element from the second STA MLD, and performing MU EDCA operation on at least one link based on the specific element, wherein the MU EDCA mapping field may include first information associated with the at least one link and second information associated with at least one traffic identifier (TID) corresponding to the at least one link.

Description

Technical Field

[0001] The present disclosure relates to communication operations in a Wireless Local Area Network (WLAN) system, and more particularly, to a method and apparatus for performing an operation based on a traffic identifier (TID) - to - link mapping in a next - generation wireless LAN system.

Background Art

[0002] New technologies for improving the transmission rate, increasing the bandwidth, improving the reliability, reducing errors, and reducing latency in a Wireless Local Area Network (WLAN) have been introduced. Among WLAN technologies, the standards of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series can be referred to as Wi - Fi. For example, technologies recently introduced to WLAN include enhancements for the Very High - Throughput (VHT) of the 802.11ac standard, enhancements for the High Efficiency (HE) of the IEEE 802.11ax standard, etc.

[0003] To provide a more improved wireless communication environment, improvement technologies for Extremely High Throughput (EHT) are being discussed. For example, technologies for increased bandwidth, efficient utilization of multiple bands, Multiple Input Multiple Output (MIMO) to support increased spatial streams, and technologies for multi - access point (AP) coordination are being studied. In particular, various technologies for supporting traffic with low latency or real - time characteristics are being studied. In addition, new technologies for supporting ultra - high reliability (UHR), including improvements or extensions of EHT technology, are being discussed.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technical problem of the present disclosure is to provide a method and an apparatus for performing TID - to - link mapping - based operation in a wireless LAN system.

[0005] The technical problem of the present disclosure is to provide a method and an apparatus for applying MU (multi - user) EDCA (Enhanced Distributed Channel Access) to assign latency - sensitive traffic to a specific link in the TID - to - link mapping process of a wireless LAN system and to assign a priority for channel access to the traffic classified as latency - sensitive traffic.

[0006] The technical problem to be achieved in the present disclosure is not limited to the technical problems mentioned above. Other technical problems not mentioned will be clearly understood by those having ordinary knowledge in the technical field to which the present disclosure pertains from the following description.

Means for Solving the Problems

[0007] A method performed by a first STA MLD in a wireless LAN system according to an aspect of the present disclosure includes transmitting a specific element including a MU EDCA mapping field to a second STA MLD or receiving the specific element from the second STA MLD, and performing MU EDCA operation on at least one link based on the specific element, where the MU EDCA mapping field may include first information related to the at least one link and second information related to at least one TID corresponding to the at least one link.

[0008] In a wireless LAN system according to one aspect of the present disclosure, the method performed by the second STA MLD includes generating a specific element including a multi-user (MU) EDCA (enhanced distributed channel access) mapping field, and transmitting the specific element including the MU EDCA mapping field to the first STA MLD. The MU EDCA mapping field may include first information associated with the at least one link and second information associated with at least one traffic identifier (TID) corresponding to the at least one link.

Advantages of the Invention

[0009] According to various embodiments of the present disclosure, it is possible to provide a method and an apparatus for performing TID-to-link mapping-based operations in a wireless LAN system.

[0010] According to various embodiments of the present disclosure, it is possible to provide a method and an apparatus for applying MU EDCA to assign delay-sensitive traffic to a specific link in the TID-to-link mapping process of a wireless LAN system and to assign a priority for channel access to traffic classified as delay-sensitive traffic.

[0011] According to various embodiments of the present disclosure, by generating a link for low-latency traffic / data using a new field in the negotiation process of TID-to-link mapping, it is possible to lower the priority of non-low-latency traffic without modifying the existing TID-to-link mapping rules and to smoothly transmit and receive low-latency traffic.

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

Brief Description of the Drawings

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

[0014]

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Mode for Carrying Out the Invention

[0015] Hereinafter, preferred embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed below together with the accompanying drawings is for explaining exemplary embodiments of the present disclosure, and is not for showing the only embodiments in which the present disclosure can be implemented. The following detailed description includes specific details in order to provide a complete understanding of the present disclosure. However, it is understood by those skilled in the art that the present disclosure can be implemented without such specific details.

[0016] In some cases, to avoid obscuring the concept of the present disclosure, well-known structures and devices may be omitted, and may be shown in the form of a block diagram centered on the core functions of each structure and device.

[0017] In the present disclosure, when a certain component is "connected", "coupled" or "connected" to another component, this may include not only a direct connection relationship, but also an indirect connection relationship in which there are further other components between them. Also, in the present disclosure, the terms "including" or "having" identify the presence of the recited features, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components and / or groups thereof.

[0018] In the present disclosure, terms such as "first" and "second" are used only for the purpose of distinguishing one component from another, and are not used to limit the components. Unless otherwise specifically mentioned, they do not limit the order or importance, etc. between the components. Therefore, within the scope of the present disclosure, the first component in one embodiment can also be referred to as the second component in another embodiment, and similarly, the second component in one embodiment can also be referred to as the first component in another embodiment.

[0019] 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 forms are also intended to include the plural forms unless the context clearly dictates otherwise. The term "and / or" as used in this disclosure may refer to one of the related listed items or include any and all possible combinations of two or more of them. Also, in this disclosure, " / " between words has the same meaning as "and / or" unless otherwise specified.

[0020] The examples of this disclosure may be applied to various wireless communication systems. For example, the examples of this disclosure may be applied to a wireless LAN system. For example, the examples of this disclosure may be applied to an IEEE 802.11a / g / n / ac / ax standard-based wireless LAN. Note that the examples of this disclosure may be applied to a newly proposed IEEE 802.11bn (or, UHR) standard-based wireless LAN. Furthermore, the examples of this disclosure may also be applied to a next-generation standard-based wireless LAN after IEEE 802.11bn. Also, the examples of this disclosure may be applied to a cellular wireless communication system. For example, it may be applied to a cellular wireless communication system based on the technologies of the LTE (Long Term Evolution) series and the 5G NR (New Radio) series of the 3GPP (registered trademark) (3rd Generation Partnership Project) standard.

[0021] Hereinafter, the technical features to which the examples of this disclosure can be applied will be described.

[0022] FIG. 1 is a block configuration diagram illustrating a wireless communication device according to an embodiment of this disclosure.

[0023] The first device 100 and the second device 200 illustrated in FIG. 1 may be referred to by various terms such as a terminal, a wireless device, a WTRU (Wireless Transmit Receive Unit), a UE (User Equipment), an MS (Mobile Station), a UT (user terminal), an MSS (Mobile Subscriber Station), an MSS (Mobile Subscriber Unit), an SS (Subscriber Station), an AMS (Advanced Mobile Station), a WT (Wireless terminal), or simply a user. Also, the first device 100 and the second device 200 may be referred to by various terms such as an access point (AP), a BS (Base Station), a fixed station, a Node B, a BTS (base transceiver system), a network, an AI (Artificial Intelligence) system, an RSU (road side unit), a repeater, a router, a relay, a gateway, etc.

[0024] The devices 100 and 200 illustrated in FIG. 1 may also be referred to as a station (STA). 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, a receiving STA, etc. For example, the STAs 110 and 200 may serve as an AP (access point) or a non-AP. That is, in the present disclosure, the STAs 110 and 200 may have the functions of an AP and / or a non-AP. When the STAs 110 and 200 have the AP function, they may simply be called an AP, and when the STAs 110 and 200 have the non-AP function, they may simply be called an STA. Also, in the present disclosure, an AP may be denoted as an AP STA.

[0025] Referring to FIG. 1, the first device 100 and the second device 200 can transmit and receive wireless signals using various wireless LAN technologies (e.g., IEEE 802.11 series). The first device 100 and the second device 200 may include interfaces for a medium access control (MAC) layer and a physical layer (PHY) that comply with the provisions of the IEEE 802.11 standard.

[0026] In addition, the first device 100 and the second device 200 can further support various communication standards other than wireless LAN technologies (e.g., 3GPP LTE series, 5G NR series standards, etc.). Also, the devices of the present disclosure may be implemented by various devices such as mobile phones, vehicles, personal computers, AR (Augmented Reality) equipment, VR (Virtual Reality) equipment, etc. Further, the STA in this specification can support various communication services such as voice calls, video calls, data communication, autonomous driving, MTC (Machine-Type Communication), M2M (Machine-to-Machine), D2D (Device-to-Device), IoT (Internet-of-Things).

[0027] The first device 100 includes one or more processors 102 and one or more memories 104, and may further include one or more transceivers 106 and / or one or more antennas 108. The processor 102 controls the memory 104 and / or the transceiver 106 and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts in the present disclosure. For example, after processing the information in the memory 104 to generate a first information / signal, the processor 102 can transmit a wireless signal including the first information / signal via the transceiver 106. Also, after receiving a wireless signal including a second information / signal via the transceiver 106, the processor 102 can store the information obtained from the signal processing of the second information / signal in the memory 104. The memory 104 may be connected to the processor 102 and can store various information related to the operation of the processor 102. For example, the memory 104 can store software code including instructions for executing part or all of the processes controlled by the processor 102 or for executing the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams in the present disclosure. Here, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., the IEEE 802.11 series). The transceiver 106 may be connected to the processor 102 and can 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 in the same sense as an RF (Radio Frequency) unit. In the present disclosure, a device can also mean a communication modem / circuit / chip.

[0028] The second device 200 includes one or more processors 202 and one or more memories 204, and may further include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206 and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in the present disclosure. For example, after processing the information in the memory 204 to generate third information / signals, the processor 202 may transmit a wireless signal including the third information / signals via the transceiver 206. Also, after receiving a wireless signal including fourth information / signals via the transceiver 206, the processor 202 may store the information obtained from the signal processing of the fourth information / signals in the memory 204. The memory 204 may be connected 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 part or all of the processes controlled by the processor 202 or for executing the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in the present disclosure. Here, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., the IEEE 802.11 series). The transceiver 206 may be connected 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 in the same sense as an RF unit. In the present disclosure, the device may also mean a communication modem / circuit / chip.

[0029] Hereinafter, the hardware elements of devices 100 and 200 will be described in more detail. Although not limited thereto, 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 can implement one or more layers (e.g., functional layers such as PHY and MAC). One or more processors 102 and 202 can generate one or more PDUs (Protocol Data Units) and / or one or more SDUs (Service Data Units) according to the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams in the present disclosure. One or more processors 102 and 202 can generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams in the present disclosure. One or more processors 102 and 202 can generate a signal (e.g., a baseband signal) including a PDU, an SDU, a message, control information, data, or information according to the functions, procedures, proposals, and / or methods in the present disclosure, and provide it to one or more transceivers 106 and 206. One or more processors 102 and 202 can receive a signal (e.g., a baseband signal) from one or more transceivers 106 and 206, and obtain a PDU, an SDU, a message, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams in the present disclosure.

[0030] One or more processors 102, 202 can be referred to as a controller, microcontroller, microprocessor, or microcomputer. The one or more processors 102, 202 may be embodied by hardware, firmware, software, or a combination thereof. As an example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) may be included in the one or more processors 102, 202. The descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in the present disclosure may be embodied using firmware or software, and the firmware or software may be embodied to include modules, procedures, functions, and the like. The firmware or software configured to execute the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in the present disclosure may be included in the one or more processors 102, 202, stored in the one or more memories 104, 204, and driven by the one or more processors 102, 202. The descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in the present disclosure may be embodied by firmware or software in the form of code, instruction words, and / or a set of instruction words.

[0031] One or more memories 104, 204 may be coupled to one or more processors 102, 202 and can store various forms of data, signals, messages, information, programs, code, instructions, and / or commands. The one or more memories 104, 204 may be constituted by a ROM, a RAM, an EPROM, a flash memory, a hard drive, a register, a cache memory, a computer-readable storage medium, and / or a combination thereof. The one or more memories 104, 204 may be located inside and / or outside the one or more processors 102, 202. Also, the one or more memories 104, 204 may be coupled to the one or more processors 102, 202 by various techniques such as wired or wireless connections.

[0032] One or more transceivers 106, 206 can transmit user data, control information, radio signals / channels, etc. mentioned in the methods and / or operation sequence diagrams of the present disclosure to one or more other devices. One or more transceivers 106, 206 can receive user data, control information, radio signals / channels, etc. mentioned in the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in the present disclosure from one or more other devices. For example, one or more transceivers 106, 206 may be connected to one or more processors 102, 202 and can transmit and receive radio signals. For example, one or more processors 102, 202 can control one or more transceivers 106, 206 to transmit user data, control information, or radio signals to one or more other devices. Also, one or more processors 102, 202 can control one or more transceivers 106, 206 to receive user data, control information, or radio signals from one or more other devices. Also, one or more transceivers 106, 206 may be connected to one or more antennas 108, 208, and one or more transceivers 106, 206 may be configured to transmit and receive user data, control information, radio signals / channels, etc. mentioned in the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in the present disclosure via one or more antennas 108, 208. In the present disclosure, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106, 206 may convert received radio signals / channels, etc. from RF band signals to baseband signals in order to process the received user data, control information, radio signals / channels, etc. using one or more processors 102, 202. One or more transceivers 106, 206 may convert user data, control information, radio signals / channels, etc. processed using one or more processors 102, 202 from baseband signals to RF band signals. For this purpose, one or more transceivers 106, 206 may include (analog) oscillators and / or filters.

[0033] For example, either one of STA100 and 200 can perform the intended operation of the AP, and the other one of STA100 and 200 can perform the intended operation of a non-AP STA. For example, the transceivers 106 and 206 in FIG. 1 can perform the transmission and reception operations of signals (for example, packets or PPDUs (Physical layer Protocol Data Units) conforming to IEEE 802.11a / b / g / n / ac / ax / be / bn, etc.). Also, in the present disclosure, operations in which various STAs generate transmission and reception signals or perform data processing and calculations in advance for the transmission and reception signals may be performed by the processors 102 and 202 in FIG. 1. For example, an example of an operation in which a transmission and reception signal is generated or data processing and calculations are performed in advance for the transmission and reception signal includes: 1) an operation of determining / acquiring / configuring / calculating / decoding / encoding bit information of fields (such as SIG (signal), STF (short training field), LTF (long training field), Data, etc.) included in the PPDU; 2) an operation of determining / configuring / acquiring time resources and frequency resources (such as subcarrier resources) used for fields (such as SIG, STF, LTF, Data, etc.) included in the PPDU; 3) an operation of determining / configuring / acquiring a specific sequence (such as a pilot sequence, STF / LTF sequence, extra sequence applied to SIG) used for fields (such as SIG, STF, LTF, Data, etc.) included in the PPDU; 4) a power control operation and / or a power saving operation applied to the STA; 5) operations related to determining / acquiring / configuring / calculating / decoding / encoding an ACK signal. Also, in the following example, various information (for example, information related to fields / sub-fields / control fields / parameters / power, etc.) used by various STAs for determining / acquiring / configuring / calculating / decoding / encoding transmission and reception signals may be stored in the memories 104 and 204 in FIG. 1.

[0034] Hereinafter, the downlink (DL) means a link for communication from an AP STA to a non-AP STA, and downlink PPDUs / packets / signals, etc. may be transmitted and received through the downlink. In downlink communication, the transmitter may be part of the AP STA and the receiver may be part of the non-AP STA. The uplink (UL) means a link for communication from a non-AP STA to an AP STA, and uplink PPDUs / packets / signals, etc. may be transmitted and received through the uplink. In uplink communication, the transmitter may be part of the non-AP STA and the receiver may be part of the AP STA.

[0035] FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure is applicable.

[0036] The structure of the wireless LAN system may be composed of a plurality of components. A wireless LAN that supports STA mobility transparent to the upper layer may be provided by the interaction of the plurality of components. A BSS (Basic Service Set) corresponds to the basic building block of the wireless LAN. In FIG. 2, an example is shown in which two BSSs (BSS1 and BSS2) exist and two STAs are included as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). In FIG. 2, the ellipse representing the BSS may be understood to represent the coverage area in which the STAs included in the BSS maintain communication. This area can be referred to as the BSA (Basic Service Area). When a STA moves outside the BSA, it can no longer communicate directly with other STAs within the BSA.

[0037] If the DS shown in FIG. 2 is not considered, the most basic type of BSS in a wireless LAN is an Independent BSS (IBSS). For example, an IBSS can have the smallest form consisting of only two STAs. For example, assuming that other components are omitted, BSS1 composed of only STA1 and STA2, or BSS2 composed of only STA3 and STA4 can each correspond to a typical exemplification of an IBSS. Such a configuration is possible when an STA can communicate directly without an AP. Also, such a form of wireless LAN is not pre-planned and configured, but can be configured when a LAN is needed, and this can also be referred to as an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity that performs management functions centrally. That is, in an IBSS, STAs are managed in a distributed manner. In an IBSS, all STAs may be composed of mobile STAs, connection to a distributed system (DS) is not allowed, and it forms a self-contained network.

[0038] Due to an STA joining or leaving, or an STA entering or departing from a BSS area, the membership of STAs in a BSS may be dynamically changed. In order to become a member of a BSS, an STA can join the BSS using a synchronization process. In order to access all services of a BSS-based structure, an STA needs to be associated with the BSS. Such an association may be set dynamically and may include the use of a Distribution System Service (DSS).

[0039] In a wireless LAN, the direct STA-to-STA distance may be limited by PHY performance. In some cases, such distance limitations are sufficient, but in some cases, communication between STAs at a greater distance may be required. A distributed system (DS) may be configured to assist with extended coverage.

[0040] DS means the structure in which BSSs are interconnected. Specifically, as shown in FIG. 2, a BSS may exist as a component of an extended form of a network composed of a plurality of BSSs. DS is a logical concept and may be specified by the characteristics of a distributed system medium (DSM). In this connection, a wireless medium (Wireless Medium, WM) and DSM may be logically separated. Each logical medium is used for different purposes and is used by different components. These media are not limited to being the same or different. The flexibility of the wireless LAN structure (DS structure or other network structures) can be explained in that a plurality of media are logically different from each other. That is, the wireless LAN structure may be implemented in various ways, and the wireless LAN structure may be specified independently according to the physical characteristics of each implementation example.

[0041] DS can assist mobile devices by providing seamless integration of a plurality of BSSs and providing the logical services necessary for handling addresses to destinations. Further, DS may further include a component called a portal that acts as a bridge for connecting a wireless LAN and other networks (e.g., IEEE 802.X).

[0042] AP means an entity that enables access to the DS through the WM for associated non-AP STAs and also has the functionality of an STA. Data movement between the BSS and the DS can be performed via the AP. For example, STAs 2 and 3 shown in FIG. 2 provide the function of enabling associated non-AP STAs (STAs 1 and 4) to access the DS while having the functionality of an STA. Also, since all APs basically 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 composed of an AP and one or more STAs can be referred to as an infrastructure BSS.

[0043] Data transmitted from one of the STAs associated with an AP to the STA address of the AP is always received at an uncontrolled port and may be processed by an IEEE 802.1X port access entity. Also, when the controlled port is authenticated, the transmitted data (or frame) can be transmitted to the DS.

[0044] An Extended Service Set (ESS) for providing a wider coverage may be set in the structure of the DS described above.

[0045] An ESS means a network composed of a DS and BSSs, having an arbitrary size and complexity. An ESS may correspond to a set of BSSs connected to one DS. However, an ESS does not include a DS. The ESS network is characterized in that it appears as an IBSS at the LLC (Logical Link Control) layer. STAs included in an ESS can communicate with each other, and a mobile STA can transparently move from one BSS to another (within the same ESS) to the LLC. APs included in one ESS may have the same SSID (service set identification). The SSID is distinguished from the BSSID, which is the identifier of the BSS.

[0046] In a wireless LAN system, without making any assumptions about the relative physical positions of BSSs, any of the following forms is possible. BSSs may partially overlap, which is a commonly used form to provide continuous coverage. Also, BSSs do not have to be physically connected, and logically there is no limit to the distance between BSSs. Also, BSSs may be physically located at the same position, which may be used to provide redundancy. Also, one (or one or more) IBSS or ESS networks may physically exist in the same space as one (or one or more) ESS networks. This may correspond to the ESS network form when an ad hoc network operates at the location where an ESS network exists, when wireless networks physically overlapping by different organizations are configured, or when two or more different access and security policies are required at the same location.

[0047] FIG. 3 is a diagram for explaining a link setup process to which the present disclosure is applicable.

[0048] In order for a STA to set up a link with a network and transmit and receive data, first, it must discover the network, perform authentication, establish an association, and carry out authentication procedures for security. The link setup process can be referred to as the session start process and the session setup process. Also, the processes of discovery, authentication, association, and security setup in the link setup process can be collectively referred to as the association process.

[0049] In step S310, the STA can perform a network discovery operation. The network discovery operation may include the scanning operation of the STA. That is, in order for the STA to access the network, it must search for available networks to participate in. The STA must identify compatible networks before participating in a wireless network, and the process of identifying networks existing in a specific area is called scanning.

[0050] Scanning methods include active scanning and passive scanning. In FIG. 3, by way of example, a network discovery operation including an active scanning process is shown. In active scanning, the STA performing the scanning sends a probe request frame to search for what APs exist in the vicinity while moving channels, and waits for a response thereto. The responder sends a probe response frame as a response to the probe request frame to the STA that sent the probe request frame. Here, the responder may be the STA that last sent a beacon frame in the BSS of the channel being scanned. Since the AP sends a beacon frame in the BSS, the AP becomes the responder, and in the IBSS, since the STAs within the IBSS send beacon frames alternately, the responder is not constant. For example, a STA that sends a probe request frame on channel 1 and receives a probe response frame on channel 1 saves the BSS-related information included in the received probe response frame, moves to the next channel (e.g., channel 2), and can perform scanning in the same way (i.e., send and receive probe requests / responses on channel 2).

[0051] Although not shown in FIG. 3, the scanning operation may be performed in a passive scanning mode. In passive scanning, the STA performing the scanning waits for beacon frames while moving channels. A beacon frame is one of the management frames defined in IEEE 802.11, which notifies the existence of a wireless network and is periodically transmitted so that the STA performing the scanning can search for a wireless network and participate in the wireless network. In a BSS, the AP plays the role of periodically transmitting beacon frames, and in an IBSS, the STAs within the IBSS transmit beacon frames alternately. When the STA performing the scanning receives a beacon frame, it stores the information regarding the BSS included in the beacon frame and records the beacon frame information on each channel while moving to other channels. The STA that has received a beacon frame can store the BSS-related information included in the received beacon frame and move to the next channel to perform scanning on the next channel in the same way. Comparing active scanning and passive scanning, active scanning has the advantage of having less delay and power consumption than passive scanning.

[0052] After the STA discovers the network, an authentication process may be performed in step S320. Such an authentication process can be called the first authentication process in order to clearly distinguish it from the security setup operation in step S340 described later.

[0053] The authentication process includes a process in which the STA transmits an authentication request frame (authentication request frame) to the AP and, in response, the AP transmits an authentication response frame to the STA. The authentication frame used for authentication request / response corresponds to a management frame.

[0054] The authentication frame may include information regarding the authentication algorithm number, authentication transaction sequence number, status code, challenge text, RSN (Robust Security Network), Finite Cyclic Group, etc. This corresponds to an example of some of the information that may be included in the authentication request / response frame, and may be replaced by other information or further additional information may be included.

[0055] 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 included in the received authentication request frame. The AP can provide the result of the authentication process to the STA using an authentication response frame.

[0056] After the STA is successfully authenticated, the association process may be performed at stage S330. The association process includes the process where the STA sends an association request frame to the AP and, in response, the AP sends an association response frame to the STA.

[0057] For example, the association request frame may include information regarding various capabilities, a beacon listening interval, an SSID (service set identifier), supported rates, supported channels, an RSN, a mobility domain, supported operating classes, a TIM (Traffic Indication Map) broadcast request, information regarding interworking service capabilities, and the like. For example, the association response frame may include information regarding various capabilities, a status code, an AID (Association ID), supported rates, an EDCA (Enhanced Distributed Channel Access) parameter set, an RCPI (Received Channel Power Indicator), an RSNI (Received Signal to Noise Indicator), a mobility domain, a timeout interval (e.g., an association comeback time), overlapping BSS scan parameters, a TIM broadcast response, a QoS (Quality of Service) map, and the like. This corresponds to an example of some of the information that may be included in the association request / response frame, and may be replaced by other information or may further include additional information.

[0058] After the STA has successfully associated with 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 an RSNA (Robust Security Network Association) request / response. The authentication process in step S320 may be referred to as a first authentication process, and the security setup process in step S340 may simply be referred to as an authentication process.

[0059] The security setup process in stage S340 may include a process of performing private key setup using, for example, 4-way handshaking using EAPOL (Extensible Authentication Protocol over LAN) frames. Further, the security setup process may be performed by a security method not defined by the IEEE 802.11 standard.

[0060] FIG. 4 is a diagram for explaining a backoff process to which the present disclosure is applicable.

[0061] In a wireless LAN system, the basic access mechanism of MAC (Medium Access Control) is the CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) mechanism. The CSMA / CA mechanism, also called the Distributed Coordination Function (DCF) of IEEE 802.11 MAC, basically adopts a "listen before talk" access mechanism. According to such a type of access mechanism, the AP and / or STA can perform a Clear Channel Assessment (CCA) to sense the wireless channel or medium (e.g., DIFS (DCF Inter-Frame Space)) for a predetermined time interval prior to starting transmission. As a result of the sensing, if it is determined that the medium is in an idle status, frame transmission can be started through the medium. On the other hand, if the medium is sensed as being in an occupied or busy state, the AP and / or STA does not start its own transmission and can set a delay period for medium access (e.g., a random backoff period) and wait, and then attempt frame transmission. By applying the random backoff period, it is expected that multiple STAs will attempt frame transmission after waiting for different times from each other, so collisions can be minimized.

[0062] In addition, the IEEE 802.11 MAC protocol provides HCF (Hybrid Coordination Function). HCF is based on the above-mentioned DCF and PCF (Point Coordination Function). PCF refers to a polling-based synchronous access method, which periodically polls so that all receiving APs and / or STAs can receive data frames. In addition, HCF has EDCA (Enhanced Distributed Channel Access) and HCCA (HCF Controlled Channel Access). EDCA is an access method in which the provider makes the access method for providing data frames to multiple users be contention-based, and HCCA is to use a non-contention-based channel access method using a polling mechanism. In addition, HCF includes a medium access mechanism for improving the QoS (Quality of Service) of a wireless LAN, and QoS data can be transmitted in either the Contention Period (CP) or the Contention Free Period (CFP).

[0063] Referring to FIG. 4, the operation based on the random backoff period will be described. When the medium that was in the occupied / busy state changes to the idle state, multiple STAs can attempt to transmit data (or frames). As a solution to minimize collisions, each STA can select a random backoff count and wait for the corresponding slot time before attempting to transmit. The random backoff count has a pseudo-random integer value and can be determined to be any one of the values in the range of 0 to CW. Here, CW is the contention window parameter value. The CW parameter is given an initial value of CWmin, but can take on a value twice as large in the case of a transmission failure (for example, when an ACK for the transmitted frame cannot be received). When the CW parameter value reaches CWmax, data transmission can be attempted while maintaining the CWmax value until successful data transmission, and when successful data transmission occurs, it is reset to the CWmin value. The CW, CWmin, and CWmax values are preferably set to 2 n -1 (n = 0, 1, 2,...).

[0064] When the random backoff process starts, the STA continues to monitor the medium while counting down the backoff slots by the determined backoff count value. When the medium is monitored as being in the occupied state, the countdown stops and it waits, and when the medium becomes idle, the remaining countdown resumes.

[0065] In the example of FIG. 4, when a packet to be transmitted arrives at the MAC of STA3, STA3 can immediately transmit a frame after confirming that the medium has been idle for only the DIFS period. The remaining STAs monitor that the medium is in an occupied / busy state and wait. During this time, data to be transmitted may occur at each of STA1, STA2, and STA5. When each STA monitors that the medium is in an idle state, after waiting for only the DIFS period, it can count down the backoff slots according to the random backoff count value it has selected. Assume that STA2 selects the minimum backoff count value and STA1 selects the maximum backoff count value. That is, an example is shown in which when STA2 finishes the backoff count and starts frame transmission, the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1. STA1 and STA5 pause the countdown and wait for a while while STA2 occupies the medium. When STA2's occupation ends and the medium becomes idle again, STA1 and STA5 wait for only the DIFS period and then resume the paused backoff count. That is, after counting down the remaining backoff slots for only the remaining backoff time, frame transmission can be started. Since the remaining backoff time of STA5 is shorter than that of STA1, STA5 starts frame transmission. Data to be transmitted may also occur at STA4 while STA2 occupies the medium. From the perspective of STA4, when the medium becomes idle, after waiting for only the DIFS period, it can perform countdown according to the random backoff count value it has selected and start frame transmission. The example of FIG. 4 shows a case where the remaining backoff time of STA5 accidentally coincides with the random backoff count value of STA4. In this case, a collision may occur between STA4 and STA5. If a collision occurs, neither STA4 nor STA5 can receive an ACK, and the data transmission will fail. In this case, STA4 and STA5 can select a random backoff count value after doubling the CW value and perform countdown.STA1 waits while the medium is busy due to the transmissions of STA4 and STA5. However, when the medium becomes idle, after waiting for only DIFS, if the remaining backoff time elapses, it can start transmitting a frame.

[0066] As shown in the example of FIG. 4, a data frame is a frame used for transmitting data to be forwarded to an upper layer, and may be transmitted after a backoff that occurs after the elapse of DIFS from when the medium becomes idle. Further, a management frame is a frame used for exchanging management information that is not forwarded to an upper layer, and is transmitted after a backoff that occurs after the elapse of an IFS such as DIFS or PIFS (Point coordination function IFS). As subtypes of management frames, there are Beacon, Association request / response, Re - association request / response, Probe request / response, Authentication request / response, etc. A control frame is a frame used for controlling access to the medium. As subtypes of control frames, there are RTS (Request - To - Send), CTS (Clear - To - Send), ACK (Acknowledgment), PS - Poll (Power Save - Poll), BlockAck, BlockACKReq, NDP null data packet announcement, Trigger, etc. A control frame is transmitted after a backoff that occurs after the elapse of DIFS when it is not a response frame to a previous frame, and is transmitted without a backoff after the elapse of SIFS (short IFS) when it is a response frame to a previous frame. The type and subtype of a frame may be identified by the type field and subtype field in the frame control (FC) field.

[0067] A QoS (Quality of Service) STA can transmit a frame after a backoff that occurs after the expiration of AIFS (Arbitration IFS) for the access category (AC) to which the frame belongs, that is, AIFS[i] (where i is a value determined by the AC). Here, the frames for which AIFS[i] can be used can be data frames, management frames, or control frames that are not response frames.

[0068] FIG. 5 is a diagram for explaining a CSMA / CA-based frame transmission operation to which the present disclosure is applicable.

[0069] As described above, the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing in which a STA directly senses a medium. Virtual carrier sensing is for complementing 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 NAV (Network Allocation Vector). The NAV is a value that indicates to other STAs the time remaining until the medium becomes available for a STA that is currently using the medium or has the right to use it. Therefore, the value set as the NAV corresponds to the period during which the use of the medium is planned by the STA that transmits the frame, and the STA that receives the NAV value is prohibited from accessing the medium during that period. For example, the NAV may be set based on the value of the "duration" field in the MAC header of the frame.

[0070] In the example of FIG. 5, assume that STA1 is about to send 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.

[0071] To reduce the possibility of transmission collisions among multiple STAs in the CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames may be applied. In the example of FIG. 5, while the transmission of STA1 is in progress, as a result of the carrier sensing of STA3, it may be determined that the medium is idle. That is, STA1 may be a hidden node to STA3. Or, in the example of FIG. 5, while the transmission of STA2 is in progress, as a result of the carrier sensing of STA3, it may be determined that the medium is idle. That is, STA2 may be a hidden node to STA3. Before performing data transmission and reception between STA1 and STA2, by exchanging RTS / CTS frames, STAs outside the transmission range of either STA1 or STA2, or STAs outside the carrier sensing range for the transmission from STA1 or STA3, can be prevented from attempting to occupy the channel during the data transmission and reception between STA1 and STA2.

[0072] Specifically, STA1 can use carrier sensing to determine whether the channel is in use. In terms of physical carrier sensing, STA1 can determine the channel occupancy idle state based on the energy magnitude or signal correlation detected from the channel. Also, in terms of virtual carrier sensing, STA1 can use the NAV (network allocation vector) timer to determine the occupancy state of the channel.

[0073] When the channel is idle at DIFS, STA1 can send an RTS frame to STA2 after performing backoff. When STA2 receives the RTS frame, it can send a CTS frame, which is a response to the RTS frame, to STA1 after SIFS.

[0074] Although STA3 cannot overhear the CTS frame from STA2, if it can overhear the RTS frame from STA1, STA3 can set the NAV timer for the subsequent consecutive frame transmission period (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame) using the duration information included in the RTS frame. Or, although STA3 cannot overhear the RTS frame from STA1, if it can overhear the CTS frame from STA2, STA3 can set the NAV timer for the subsequent consecutive frame transmission period (e.g., SIFS + data frame + SIFS + ACK frame) using the duration information included in the CTS frame. That is, when STA3 can overhear one or more of the RTS or CTS frames from at least one of STA1 or STA2, it can set the NAV based on this. 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.

[0075] When STA1 receives the CTS frame from STA2, it can transmit a data frame to STA2 after SIFS from the time when the reception of the CTS frame is completed. When STA2 successfully receives the data frame, it can transmit an ACK frame, which is a response to the data frame, to STA1 after SIFS. When the NAV timer of STA3 expires, it can use carrier sensing to determine whether the channel is in use. If STA3 determines that the channel is not used by other terminals during the period from the expiration of the NAV timer to DIFS, it can attempt channel access after the contention window (CW) of the random backoff has passed.

[0076] FIG. 6 is a diagram for explaining an example of a frame structure used in a wireless LAN system to which the present disclosure is applicable.

[0077] By an instruction or primitive (meaning a set of an instruction or parameters) from the MAC layer, the PHY layer can prepare an MPDU (MAC PDU) to be transmitted. For example, when receiving an instruction requesting the start of transmission from the MAC layer, the PHY layer switches to the transmission mode and can configure and transmit information (e.g., data) provided from the MAC layer in the form of a frame. Also, when the PHY layer detects a valid preamble of the received frame, it monitors the preamble header and sends an instruction to the MAC layer notifying the start of reception of the PHY layer.

[0078] In this way, information transmission / reception in the wireless LAN system is performed in the form of a frame, and for this purpose, a Physical layer Protocol Data Unit (PPDU) frame format is defined.

[0079] A basic PPDU may include a STF (Short Training Field), an LTF (Long Training Field), a SIG (SIGNAL) field, and a Data field. The most basic (e.g., non-HT (High Throughput) shown in FIG. 7) PPDU format may be composed of only an L-STF (Legacy-STF), an L-LTF (Legacy-LTF), an L-SIG (Legacy-SIG) field, and a Data field. Also, depending on the type of PPDU format (e.g., HT-mixed format PPDU, HT-greenfield format PPDU, VHT (Very High Throughput) PPDU, etc.), additional (or other types of) RL-SIG, U-SIG, non-legacy SIG fields, non-legacy STF, non-legacy LTF (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) may be included between the L-SIG field and the Data field. More specific matters will be described later with reference to FIG. 7.

[0080] 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. It can be said that the STF and the LTF are signals for synchronization and channel estimation of the OFDM physical layer.

[0081] The SIG field may contain various information related to PPDU transmission and reception. For example, the L-SIG field is composed of 24 bits, and the L-SIG field may include a 4-bit Rate field, a 1-bit Reserved bit, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field. 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 non-HT, HT, VHT, or EHT PPDUs, the value of the Length field may be determined to be a multiple of 3. For example, for HE PPDUs, the value of the Length field may be determined to be a multiple of 3 + 1 or a multiple of 3 + 2.

[0082] The data field may include a SERVICE field, a PSDU (Physical layer Service Data Unit), PPDU TAIL bits, and, if necessary, padding bits. Some bits of the SERVICE field may be used for synchronization of the descrambler at the receiving end. The PSDU corresponds to the MAC PDU defined at the MAC layer and may include data generated / used at the upper layer. The PPDU TAIL bits may be used to return the encoder to the 0 state. The padding bits may be used to align the length of the data field to a predetermined unit.

[0083] The MAC PDU is defined by various MAC frame formats, and the basic MAC frame is composed of a MAC header, a frame body, and an FCS (Frame Check Sequence). The MAC frame is composed of MAC PDUs and may be transmitted / received by the PSDU in the data part of the PPDU format.

[0084] The MAC header includes a Frame Control field, a Duration / ID field, an Address field, etc. The Frame Control field may include control information necessary for frame transmission / reception. The Duration / ID field may be set to the time for transmitting the frame, etc. The address subfield can indicate the receiver address, transmitter address, destination address, and source address of the frame, and some address subfields may be omitted. It includes Sequence Control, QoS Control, and HT Control subfields, and the specific content of each subfield of the MAC header can be referred to in the IEEE 802.11 standard document.

[0085] The Null Data PPDU (NDP) format means a PPDU format that does not include a data field. That is, NDP means a frame format that includes PPDU preambles (i.e., L-STF, L-LTF, L-SIG fields, and, if present, further non-legacy SIG, non-legacy STF, non-legacy LTF) in the general PPDU format and does not include the remaining part (i.e., the data field).

[0086] FIG. 7 is a diagram showing an exemplification of a PPDU defined in the IEEE 802.11 standard to which the present disclosure is applicable.

[0087] In standards such as IEEE 802.11a / g / n / ac / ax, various forms of PPDUs are used. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and Data fields. The basic PPDU format can also be referred to as the non-HT PPDU format (FIG. 7(a)).

[0088] The HT PPDU format (IEEE 802.11n) further includes HT-SIG, HT-STF, HT-LFT(s) fields in the basic PPDU format. The HT PPDU format shown in Figure 7(b) can be referred to as the HT-mixed format. An HT-greenfield format PPDU may be further defined, which corresponds to a format composed of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a Data field without including L-STF, L-LTF, and L-SIG (not shown).

[0089] An example of the VHT PPDU format (IEEE 802.11ac) further includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in the basic PPDU format (Figure 7(c)).

[0090] An example of the HE PPDU format (IEEE 802.11ax) further includes RL-SIG (Repeated L-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), and PE (Packet Extension) fields in the basic PPDU format (Figure 7(d)). Depending on the detailed illustration of the HE PPDU format, some fields may be excluded or their lengths may change. For example, the HE-SIG-B field is included in the HE PPDU format for multiple users (MU) and not included in the HE PPDU format for a single user (SU). Also, the HE trigger-based (TB) PPDU format does not include the HE-SIG-B field, and the length of the HE-STF field may change to 8 us. The HE ER (Extended Range) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may change to 16 us. For example, RL-SIG may be configured identically to L-SIG. The receiving STA can determine that the received PPDU is an HE PPDU or an EHT PPDU described later based on the presence of RL-SIG.

[0091] The EHT PPDU format may include the EHT MU (multi-user) in FIG. 7(e) and the EHT TB (trigger-based) PPDU in FIG. 7(f). The EHT PPDU format is similar to the HE PPDU format in that it includes an RL-SIG following the L-SIG, but may include a U (universal)-SIG, an EHT-SIG, an EHT-STF, and an EHT-LTF following the RL-SIG.

[0092] The EHT MU PPDU in FIG. 7(e) corresponds to a PPDU that carries one or more data (or PSDU) for one or more users. That is, the EHT MU PPDU may be used for either SU transmission or MU transmission. For example, the EHT MU PPDU may correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0093] The EHT TB PPDU in FIG. 7(f) omits the EHT-SIG compared to the EHT MU PPDU. A STA that receives a trigger (e.g., a trigger frame or TRS (triggered response scheduling)) for UL MU transmission can perform UL transmission based on the EHT TB PPDU format.

[0094] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal SIGNAL), and EHT-SIG fields may be encoded and modulated so that a legacy STA can also attempt demodulation and decoding, and may be mapped based on a defined subcarrier frequency interval (e.g., 312.5 kHz). These can be referred to as pre-EHT modulated fields. Next, the EHT-STF, EHT-LTF, Data, and PE fields may be encoded and modulated so that they can be demodulated and decoded by an STA that has successfully decoded a non-legacy SIG (e.g., U-SIG and / or EHT-SIG) and obtained the information contained in the field, and may be mapped based on a defined subcarrier frequency interval (e.g., 78.125 kHz). These can be referred to as EHT modulated fields.

[0095] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields can be referred to as pre-HE modulated fields, and the HE-STF, HE-LTF, Data, and PE fields can be referred to as HE modulated fields. Also, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be referred to as pre-VHT modulated fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields can be referred to as VHT modulated fields.

[0096] The U-SIG included in the EHT PPDU format of FIG. 7 may be configured based on, for example, 2 symbols (e.g., 2 consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG may have a duration of 4 us, and the U-SIG may have an overall 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.

[0097] The U-SIG may be configured in units of 20 MHz. For example, when an 80 MHz PPDU is configured, the same U-SIG may be replicated in units of 20 MHz. That is, the same four U-SIGs may be included in the 80 MHz PPDU. When exceeding the 80 MHz bandwidth, for example, for a 160 MHz PPDU, the U-SIG of the first 80 MHz unit and the U-SIG of the second 80 MHz unit may be different from each other.

[0098] In the U-SIG, for example, A uncoded bits may be transmitted. The first symbol of the U-SIG (for example, the U-SIG-1 symbol) may transmit the first X bits of the total A-bit information, and the second symbol of the U-SIG (for example, the U-SIG-2 symbol) may transmit the remaining Y bits of the total A-bit information. The A-bit information (for example, 52 uncoded bits) may include a CRC field (for example, a 4-bit long field) and a tail field (for example, a 6-bit long field). The tail field may be used to terminate the trellis of the convolutional decoder and may be set to 0, for example.

[0099] The A-bit information transmitted by the U-SIG can be distinguished into version-independent bits and version-dependent bits. For example, the U-SIG may be included in a new PPDU format (for example, the 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, and some or all of the version-dependent bits may be different.

[0100] For example, the size of the version-independent bits of U-SIG may be fixed or variable. The version-independent bits may be assigned only to U-SIG-1 symbols, or may be assigned to both U-SIG-1 symbols and U-SIG-2 symbols. The version-independent bits and the version-dependent bits may be called by various names such as the first control bit and the second control bit.

[0101] For example, the version-independent bits of U-SIG may include a 3-bit physical layer version identifier, and this information can indicate the PHY version (such as EHT, UHR, etc.) of the transmitted and received PPDU. The version-independent bits of U-SIG may include a 1-bit UL / DL flag field. The first value of the 1-bit UL / DL flag field is related to UL communication, and the second value of the UL / DL flag field is related to DL communication. The version-independent bits of U-SIG may include information regarding the length of the TXOP (transmission opportunity) and information regarding the BSS color ID.

[0102] For example, the version-dependent bits of U-SIG may include information that directly or indirectly indicates the type of PPDU (such as SU PPDU, MU PPDU, TB PPDU, etc.).

[0103] The information necessary for the transmission and reception of PPDU may be included in U-SIG. For example, U-SIG may further include information regarding the bandwidth, information regarding the MCS method applied to non-legacy SIG (such as EHT-SIG or UHR-SIG, etc.), information indicating whether a DCM (dual carrier modulation) method (such as reusing the same signal on two subcarriers) is applied to achieve an effect similar to frequency diversity for non-legacy SIG, information regarding the number of symbols used for non-legacy SIG, information regarding whether non-legacy SIG is generated over the entire bandwidth, etc.

[0104] 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 regarding the type of non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information regarding the length of the non-legacy LTF and the CP (cyclic prefix) length, information regarding the GI (guard interval) applied to the non-legacy LTF, information regarding the preamble puncturing applicable to the PPDU, information regarding the RU (resource unit) allocation, etc. may be included only in the U-SIG, may be included only in the non-legacy SIG, or may be indicated by a combination of the information included in the U-SIG and the information included in the non-legacy SIG.

[0105] Preamble puncturing can mean the transmission of a PPDU where there is no signal present in one or more frequency units in the bandwidth of the PPDU. 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 a PPDU bandwidth of a predetermined size or more.

[0106] In the example of FIG. 7, non-legacy SIGs such as HE-SIG-B and EHT-SIG may include control information for the receiving STA. The non-legacy SIG may be transmitted in at least one symbol, and one symbol may have a length of 4 us. Information regarding the number of symbols used for the EHT-SIG may be included in a previous SIG (e.g., HE-SIG-A, U-SIG, etc.).

[0107] Non-legacy SIGs such as HE-SIG-B and EHT-SIG may include a common field and user-specific fields. The common field and user-specific fields may be coded separately.

[0108] In some cases, the common field may be omitted. For example, the common field may be omitted in a compression mode where non-OFDMA (orthogonal frequency multiple access) is applied, and multiple STAs can receive a PPDU (e.g., the data field of the PPDU) in the same frequency band. In a non-compression mode where OFDMA is applied, multiple users can receive a PPDU (e.g., the data field of the PPDU) in individual frequency bands.

[0109] The number of user-specific fields may be determined based on the number of users. One user block field may include a maximum of two user fields. Each user field may be related to MU-MIMO allocation or non-MU-MIMO allocation.

[0110] The common field may include CRC bits and Tail bits. 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 may be set to 000000. The common field may include RU allocation information. The RU allocation information may include information about the location of the RUs assigned to multiple users (i.e., multiple receiving STAs).

[0111] An RU may include a plurality of subcarriers (or tones). An RU may be used when transmitting signals to a plurality of STAs based on the OFDMA technique. Also, an RU may be defined when transmitting signals to one STA. Resources may be allocated in units of RUs for non-legacy STF, non-legacy LTF, and Data fields.

[0112] The size of the RU applicable according to the PPDU bandwidth may be defined. The RU may be defined to be the same or different for the applicable PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80 MHz PPDU, the RU arrangements of the HE PPDU and the EHT PPDU may be different from each other. The size of the RU applicable according to the PPDU bandwidth, the number of RUs, the RU position, the DC (direct current) subcarrier position and number, the null subcarrier position and number, the guard subcarrier position and number, etc. can be referred to as a tone-plan. For example, the tone-plan for a wide bandwidth may be defined in the form of multiple repetitions of the tone-plan for a low bandwidth.

[0113] RUs of various sizes may be defined such as 26-tone RU, 52-tone RU, 106-tone RU, 242-tone RU, 484-tone RU, 996-tone RU, 2×996-tone RU, 4×996-tone RU, etc. An MRU (multiple RU) is distinguished from a plurality of individual RUs and corresponds to a group of subcarriers composed of a plurality of 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. Also, the plurality of RUs constituting one MRU may or may not be continuous in the frequency domain.

[0114] The specific size of the RU may be reduced or expanded. Therefore, in the present disclosure, the specific size of each RU (i.e., the number of corresponding tones) is illustrative rather than restrictive. Also, in the present disclosure, within a predetermined bandwidth (e.g., 20, 40, 80, 160, 320 MHz,...), the number of RUs may vary depending on the size of the RU.

[0115] In the PPDU format of FIG. 7, the names of the respective fields are illustrative, and the scope of the present disclosure is not limited by the names. Also, 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 excluded and / or some fields are added based on the PPDU format of FIG. 7.

[0116] TID-to-Link Mapping

[0117] Hereinafter, the TID-to-Link mapping in link management (LM) will be described. Here, TID means an identifier that can be used by an upper-layer entity to distinguish a MAC entity that supports Quality of Service (QoS) within a MAC data service from a MAC service data unit (MSDU).

[0118] For example, 16 possible TID values may exist. Among the 16 TID values, 8 can identify a traffic category (TC), and the remaining 8 can identify a parameterized traffic stream (TS). The TID may be assigned to the MSDU of the MAC upper layer.

[0119] The TID-to-link mapping mechanism means a mechanism that enables an AP MLD (multi-link device) and a non-AP MLD that have performed a multi-link setup to determine the method by which the setup links and TIDs are mapped in the DL and UL.

[0120] Here, an MLD is a logical entity that has one or more affiliated STAs and means a device that has a single MAC service access point for one MAC data service and logical link control (LLC).

[0121] A non-AP MLD means an MLD in which each STA belonging to the MLD is a non-AP STA. A multi-radio non-AP MLD means a non-AP MLD that supports frame reception or exchange on one or more links at a time. An AP MLD means an MLD in which each STA belonging to the MLD is an AP.

[0122] Basically (By default), all TIDs must be mapped to all setup links for both the DL and UL. When both MLDs have explicitly negotiated the TID-to-link mapping, each TID may be mapped to the same or different link sets from each other.

[0123] When at least one TID (traffic identifier) is mapped to the link, the setup link is defined as enabled, and when there is no TID mapped to the link, the setup link may be defined as disabled. The TID must always be mapped to one or more setup links unless admission control is used. Basically, since the TID is mapped to all setup links, all setup links can be enabled.

[0124] When the link is enabled, the link may be used for frame exchange depending on the power state of the non-AP STA operating on the link. Only an MSDU or A-MSDU with a TID mapped to the enabled link may be transmitted on the link. Management frames and control frames may be transmitted only on the enabled link.

[0125] When the link is disabled, the link may include management frames for both DL and UL and may not be used for frame exchange.

[0126] In the multi-link setup process, the activation / deactivation of each link can be indicated by the TID-to-link mapping. The TID-to-link mapping may be performed in the default mapping mode and / or the negotiation mapping mode.

[0127] The default mapping mode means the mode in which all TIDs are mapped to links by the AP. Specifically, in the default mapping mode, all TIDs are mapped to all setup links for DL and UL, and all setup links may be activated. The non-AP MLD and the AP MLD that has performed multi-link setup can operate in the default mapping mode when there is no TID-to-link mapping negotiation for other mappings, or when the negotiation fails, or when it is torn down.

[0128] The negotiation mapping mode means the mode in which if the STA sends information about the link to be mapped to the TID to the AP using the TID-to-link mapping element included in the (re)association request frame or the TID-to-link mapping request frame, the AP approves or rejects it accordingly.

[0129] Specifically, the MLD can support TID-to-link mapping negotiation. The MLD that supports TID-to-link mapping negotiation has "dot11TIDtoLinkMappingActivated" which is "true", and can set the value of the TID-to-link mapping negotiation supported sub-field in the MLD Capabilities field of the basic variant multi-link element to a value other than 0. Otherwise, the said MLD can set the value of the "TID-to-link mapping negotiation supported" sub-field to 0.

[0130] When the AP MLD indicates support for TID-to-link mapping negotiation in the multi-link (re)setup procedure, the non-AP MLD can start TID-to-link mapping negotiation by including a TID-to-link mapping element on the (re)association request frame.

[0131] After receiving a (re)connection request frame that includes a TID-to-link mapping element, the AP MLD can respond to the (re)connection request frame according to the rules described below.

[0132] For example, the AP MLD can only approve the TID-to-link mapping requested by the TID-to-link mapping element in the received (re)connection request frame if it approves the multi-link (re)setup for all the links for which at least one TID is requested to be mapped. In this case, the AP MLD does not have to include the TID-to-link mapping element in the (re)connection response frame.

[0133] Otherwise, the AP MLD can indicate rejection of the proposed TID-to-link mapping by including in the (re)connection response frame a TID-to-link mapping element that proposes a preferred TID-to-link mapping.

[0134] After a successful multi-link (re)setup, in order to negotiate a new TID-to-link mapping, the initiating MLD having "dot11TIDtoLinkMappingActivated" as "true" can send an individually addressed TID-to-link mapping request frame to the responding MLD that has indicated support for TID-to-link mapping negotiation.

[0135] After receiving an individually addressed TID-to-link mapping request frame, the responding MLD can send an individually addressed TID-to-link mapping response frame to the initiating MLD according to the rules described below.

[0136] For example, if the responding MLD approves the TID-to-link requested by the TID-to-link mapping element of the received TID-to-link mapping request frame, the responding MLD can set the status code to 0 (SUCCESS) in the TID-to-link mapping response frame.

[0137] Otherwise, the responding MLD can indicate rejection of the proposed TID-to-link mapping by setting the status code to "DENIED_TID_TO_LINK_MAPPING" or "PREFERED_TID_TO_LINK_MAPPING_SUGGESTED" in the TID-to-link mapping response frame. The responding MLD can propose a preferred TID-link mapping by setting the "PREFERRED_TID_TO_LINK_MAPPING_SUGGESTED" status code in the TID-to-link mapping response frame and including the TID-to-link mapping element in the TID-to-link mapping response frame.

[0138] When two MLDs negotiate a TID-to-link mapping, each MLD can send an individually addressed TID-to-link mapping teardown frame to tear down the negotiated TID-to-link mapping. After the teardown, the MLD can operate in the default mapping mode.

[0139] If the MLD successfully negotiates with a peer MLD and / or for an uplink and / or downlink TID-to-link mapping where the bit position i of the Link Mapping of TID field of the TID-to-link mapping element is set to 0, TID n need not be mapped to the link associated with link ID i on the uplink and / or downlink.

[0140] If the MLD successfully negotiates with a peer MLD and / or for an uplink and / or downlink TID-to-link mapping where the bit position i of the Link Mapping of TID field of the TID-to-link mapping element is set to 1, TID n may be mapped to the link associated with link ID i on the uplink and / or downlink.

[0141] FIG. 8 illustrates a TID-to-link mapping element format and a TID-to-link control field format applicable to the present disclosure.

[0142] The TID-to-link mapping element indicates a link through which frames belonging to each TID can be exchanged. As shown in FIG. 8, the TID-to-link mapping element may include an element ID subfield, a length subfield, an element ID extension subfield, a TID-to-link mapping control subfield, and a link mapping of TID n (n is an integer equal to or greater than 0) subfield.

[0143] And the TID-to-link mapping control subfield may include a direction subfield, a default link mapping subfield, a reserved subfield, and a link mapping presence indicator subfield.

[0144] When the TID-to-link mapping element provides TID-to-link mapping information for a frame transmitted on the downlink, the direction subfield value may be set to 0 (uplink). When the TID-to-link mapping element provides TID-to-link mapping information for a frame transmitted on the uplink, the direction subfield value may be set to 1 (downlink). When the TID-to-link mapping element provides TID-to-link mapping information for a frame transmitted on both the downlink and the uplink, the direction subfield value may be set to 2 (bidirectional link). In the case of 3 in the direction subfield values, it may be reserved.

[0145] And when the TID-to-link mapping element indicates a default TID-to-link mapping, the default link mapping subfield value may be set to 1. Otherwise, the default link mapping subfield value may be set to 0.

[0146] The link mapping presence indicator subfield can indicate whether a link mapping field for TID n exists on the TID-to-link mapping element. A value of 1 at bit position n of the link mapping presence indicator subfield can indicate that a link mapping field for TID n exists on the TID-to-link mapping element. A value of 0 at bit position n of the link mapping presence indicator subfield can indicate that a link mapping field for TID n does not exist on the TID-to-link mapping element. The link mapping presence indicator subfield may be reserved when the default link mapping subfield value is set to 1.

[0147] The link mapping field for TID n can indicate a link on which the frame belonging to TID n can be transmitted. A value of 1 at bit position i of the link mapping field for TID n can indicate that TID n is mapped to the link associated with link ID i for the direction specified in the direction subfield. The link mapping field for TID n may not exist when the default link mapping subfield value is set to 1.

[0148] EDCA Operation Using MU EDCA Parameters

[0149] FIG. 9(a) illustrates the MU EDCA parameter set element format. The QoS information field included in the MU EDCA parameter set element may include an EDCA parameter set update count subfield. The EDCA parameter set update count subfield can indicate the time when the EDCA parameters and (in the case of a HE BSS) the MU EDCA parameters were changed.

[0150] The formats of the MU AC_BE, MU AC_BK, MU AC_VI, and MU AC_VO parameter record fields may all be the same. The format of the ACI / AIFSN field may be defined as in FIG. 9(b). Here, a value of 0 in the AIFSN field can indicate that EDCA is deactivated for the period specified by the MU EDCA timer for the AC.

[0151] The value of the AC index (ACI) allows all the parameters of the record to reference the AC to which they pertain. The mapping between the ACI and the AC may be defined as in Table 1.

[0152]

Table 1

[0153] The ACM (admission control required) subfield can indicate that admission control is required for the AC. When the ACM subfield value is set to 0, admission control may not be necessary for the AC. When the ACM subfield value is set to 1, admission control must be used before transmission using the access parameters specified for the AC. The AIFSN subfield can indicate the number of slots after the SIFS that the STA defers before calling for a backoff or starting a transmission. The minimum value of the AIFSN subfield may be 2.

[0154] The format of the ECWin / ECWmax field may be defined as in FIG. 9(d). The ECWmin and ECWmax subfields can each encode the values of CWmin (i.e., 2 ECWmin - 1) and CWmax (i.e., 2 ECWmax - 1) in exponential form.

[0155] The MU EDCA Timer field can indicate the duration in 8 TU units for which the HE STA uses the MU EDCA parameters for the AC, excluding reserved values.

[0156] The HE AP can set the QoS information field of the MU EDCA parameter set element to the same value as the QoS information field of the EDCA parameter set element. The HE AP can change the MU EDCA parameters by including the MU EDCA parameter set element with the updated MU EDCA parameters in the beacon frames and probe response frames to be transmitted. The EDCA parameter set update count subfield in the QoS information fields of the EDCA parameter set element and the MU EDCA parameter set element may increase each time the EDCA parameters or the MU EDCA parameters are changed.

[0157] After receiving the updated EDCA or MU EDCA parameter set from the associated AP, the Non-AP HE STA can update the "dot11EDCATable" and "dot11MUEDCATable" corresponding to the fields of the EDCA parameter set element or the MU EDCA parameter set element within the same time interval as one beacon interval. The HE STA can save the value of the EDCA parameter set update count subfield in the QoS Info field of the received EDCA parameter set element or MU EDCA parameter set element when updating its MIB attributes.

[0158] A Non-AP HE STA can use the EDCA parameter set update count subfield in the QoS function element of the beacon frame to determine whether the STA is currently using EDCA (and optionally MU EDCA) parameter values. If the value of the EDCA parameter set update count subfield is different from the saved value, the STA can send a probe request frame to the AP and query the updated EDCA (and all MU EDCA) parameter values.

[0159] When there is a QoS function element in the beacon frame, the EDCA parameter set element and the MU EDCA parameter set element may not exist. At this time, the HE STA can send a probe request frame to the AP to obtain the updated parameters. A non-AP HE STA that receives a basic trigger frame containing a user information field for the STA can update its CWmin[AC], CWmax[AC], AIFSN[AC], and MUEDCATimer[AC] state variables to the values contained in the "dot11MUEDCATable".

[0160] The QoS data frame requires immediate approval and can be successfully transmitted by the STA of the HE TB PPDU for the AC when the STA receives immediate approval for the frame or when the QoS data frame does not require immediate approval.

[0161] The MUEDCATimer[AC] state variable may be updated to the value contained in the MU EDCA timer subfield of the MU EDCA parameter set element. The backoff counter maintenance management corresponding to the updated state variable can follow the rules except that when AIFSN[AC] is 0, the EDCAF corresponding to the AC is suspended until MUEDCATimer[AC] reaches 0 or is reset to 0.

[0162] The updated MUEDCATimer[AC] should start immediately after the response if the transmitted HE TB PPDU contains one or more QoS data frames for the AC that require immediate confirmation, and it can start immediately after the HE TB PPDU when the HE TB PPDU is transmitted. The HE TB PPDU may not contain QoS data frames for the AC that require immediate confirmation.

[0163] In a non-AP HE STA, each MUEDCATimer[AC] can count down uniformly to 0 without interruption if its value is not 0.

[0164] A non-AP STA that transmits a frame to an AP where the value of the UL MU deactivation subfield is set to 1, or there is an OM control subfield where the value of the UL MU deactivation subfield is set to 0 and the value of the UL MU data deactivation subfield is set to 1, does not have to participate in UL MU operation. Therefore, it does not have to update the EDCA access parameters to the values included in the MU EDCA parameter set element.

[0165] A Non-AP STA does not have to update the state variable to the value included in the MU EDCA parameter set element if any of the following applies.

[0166] a) When the trigger frame directed to the STA is not a Basic trigger frame;

[0167] b) When the HE TB PPDU response sent by the STA as a response to the Basic trigger frame does not contain a QoS data frame;

[0168] c) When the STA transmits a HE TB PPDU as a response to a Basic trigger frame according to a predefined rule.

[0169] A non-AP STA that transmits a frame with no address specified for the associated AP can use the EDCA parameter values included in the EDCA parameter set element that was last received from the AP to which the STA is associated or the basic EDCA parameter values.

[0170] If the MUEDCATimer[AC] of a non-AP HE STA reaches 0 by countdown or reset after receiving a MU EDCA Reset frame, the STA can update CWmin[AC], CWmax[AC], and AIFSN[AC] to the values included in the EDCA parameter set element that was last received from the AP to which the STA is associated.

[0171] A non-AP HE STA that transmits a frame in which the UL MU deactivation subfield is set to 1 or there is an OM control subfield in which the UL MU deactivation subfield is set to 0 and the UL MU data deactivation subfield is set to 1 can set MUEDCATimer[AC] to 0 for all ACs when it receives an immediate confirmation from the OMI responder.

[0172] The STA can perform the current EDCA backoff procedure without modifying the backoff counter for QSRC[AC], QLRC[AC], or the associated EDCAF regardless of whether MUEDCATimer[AC] has reached 0 until it invokes a new EDCA backoff procedure.

[0173] In response to the reset of MUEDCATimer[AC], after MUEDCATimer[AC] has been reset for the AC and after CWmin[AC], CWmax[AC], and AIFSN[AC] have been updated for the AC, the STA can invoke a new EDCA backoff procedure.

[0174] That is, at the time set in the MU EDCA timer subfield, the priority of MU EDCA associated with the AC indicated by the MU EDCA parameter set element may be lower than the priority of the AC in the general EDCA operation. Therefore, when the time set in the MU EDCA timer subfield ends, the priority of the AC to which MU EDCA was applied may return to the priority it has in the EDCA operation.

[0175] Method for Applying MU EDCA to TIDs Assigned by TID-to-Link Mapping

[0176] When MU EDCA is applied to some of the TIDs assigned to a link by the TID-to-link mapping, the TID may have a lower priority for channel access compared to the TIDs to which MU EDCA is not applied.

[0177] Based on the rules described above, MU EDCA may be utilized to assign one or more links between MLDs as links for delay-sensitive traffic and assign a priority for channel access to the TIDs classified as delay-sensitive traffic.

[0178] Contrary to the rule that MU EDCA is applied to a specific AC at the time set by the MU EDCA timer subfield, the present disclosure assumes a case where MU EDCA continues to be applied to the AC corresponding to the TID after the TID to which MU EDCA was applied is indicated by the TID-to-link mapping.

[0179] Hereinafter, a method of transmitting information regarding which of the TIDs assigned to one or more links in the TID-to-link mapping is to have MU EDCA applied will be described. The name of the new field proposed to support the method may be changed variously.

[0180] FIG. 10 is a diagram for explaining the operations performed by the first STA MLD according to an embodiment of the present disclosure. In FIGS. 10 and 11, the first STA MLD may mean a non-AP STA MLD, and the second STA MLD may mean an AP MLD, but is not limited thereto. Each of the first STA MLD and the second STA MLD may be at least one of a non-AP STA MLD or an AP MLD.

[0181] The first STA MLD can transmit a specific element including an (LL) MU EDCA mapping field to the second STA MLD or receive the specific element from the second STA MLD (S1010). That is, the first STA MLD can request the second STA MLD for information on a link / TID related to the (LL) MU EDCA operation or receive a request for information on a link / TID related to the (LL) MU EDCA operation from the second STA MLD.

[0182] Here, the specific element may be at least one of a TID-to-link element, an EDCA mapping element, or an LL (low latency) EDCA mapping element.

[0183] And at least one of the TID-to-link element, the EDCA mapping element, or the LL EDCA mapping element may include an EDCA control field or / and an LL EDCA control field. The MU EDCA control field or / and the LL EDCA control field may include a first subfield indicating whether the (LL) MU EDCA mapping field exists in at least one of the TID-to-link element, the EDCA mapping element, or the LL EDCA mapping element.

[0184] The MU EDCA mapping field may include first information related to at least one link performing the (LL) MU EDCA operation and second information related to at least one TID corresponding to the at least one link.

[0185] As an example of the present disclosure, the (LL)MU EDCA mapping field may include a second sub-field including an ID value of at least one link performing the (LL)MU EDCA operation or a bitmap indicating the at least one link. Here, the first information may be indicated by the second sub-field.

[0186] And the (LL)MU EDCA mapping field may include at least one third sub-field indicating at least one TID associated with the (LL)MU EDCA operation corresponding to each of the at least one link performing the (LL)MU EDCA operation. Here, the second information may be indicated by the at least one third sub-field. And the number of the at least one third sub-field may be the same as the number of the at least one link.

[0187] As an example of the present disclosure, the TID-to-link element may be configured based on a MU EDCA parameter set element or an LL MU EDCA parameter set element.

[0188] Here, the LL MU EDCA parameter set element includes a plurality of LL MU TID parameter record fields, and each of the plurality of LL MU TID parameter record fields may include an LL MU EDCA timer sub-field.

[0189] When the TID-to-link element is configured based on the LL MU EDCA parameter set element, the (LL)MU EDCA mapping field may be associated with the LL MU EDCA operation. The at least one link performing the LL MU EDCA operation may be indicated by the first information, and at least one TID associated with the LL MU EDCA operation may be indicated by the second information.

[0190] As yet another example of the present disclosure, the (LL)MU EDCA mapping field may include third information associated with at least one AC (access category) associated with the (LL)MU EDCA operation. The (LL)MU EDCA mapping field may include at least one fourth sub-field indicating at least one AC corresponding to each of at least one link. Here, the third information may be indicated by the fourth sub-field.

[0191] The first STA MLD can perform (LL)MU EDCA operations on at least one link based on specific elements (S1020).

[0192] The method performed by the first STA MLD described in the example of FIG. 10 may be performed by the first device 100 of FIG. 1. For example, one or more processors 102 of the first device 100 of FIG. 1 may be set to transmit a specific element including the MU EDCA mapping field to the second STA MLD or receive the specific element from the second STA MLD via one or more transceivers 106. One or more processors 102 may be set to perform MU EDCA operations on at least one link based on the specific elements.

[0193] Note that when one or more memories 104 of the first device 100 are executed by one or more processors 102, they can store instructions for performing the method described in the example of FIG. 10.

[0194] FIG. 11 is a diagram for explaining operations performed by a second STA MLD according to an embodiment of the present disclosure.

[0195] The second STA MLD can generate a specific element including the (LL)MU EDCA mapping field (S1110).

[0196] As an example, the second STA MLD can generate a specific element including an (LL)MU EDCA mapping field based on an (LL)MU EDCA parameter set element.

[0197] The second STA MLD can send a specific element including an MU EDCA mapping field to the first STA MLD (S1120).

[0198] The configurations of the specific element and the (LL)MU EDCA mapping field are described with reference to FIG. 10, and overlapping descriptions thereof are omitted.

[0199] The method performed by the second STA MLD described in the example of FIG. 11 may be performed by the second device 200 of FIG. 1. For example, one or more processors 202 of the second device 200 of FIG. 1 may be set to generate a specific element including an (LL)MU EDCA mapping field. The one or more processors 202 may be set to send a specific element including an MU EDCA mapping field to the first STA MLD via one or more transceivers 206.

[0200] Note that one or more memories 204 of the second device 200 can store instructions for performing the method described in the example of FIG. 11 when executed by one or more processors 202.

[0201] Hereinafter, a method of transmitting information regarding which TID among the TIDs assigned to one or more links in the TID-to-link mapping is to apply MU EDCA will be specifically described.

[0202] In the case of R (restricted)-TWT, which is a technique for transmitting and receiving LL traffic / data in a basic wireless communication system, a TWT negotiation operation, a rule for canceling a TXOP that was in progress before the start of the R-TWT SP to guarantee the R-TWT SP, and an overlapping quiet interval assigned to overlap with the R-TWT SP may be applied.

[0203] The above-described rules and operations may disadvantage STAs that do not support R-TWT. Therefore, in the TID-to-link mapping process, a specific link may be assigned as a link for delay-sensitive traffic, and MU EDCA may be utilized to give a priority for channel access to TIDs classified as delay-sensitive traffic.

[0204] The following, the method of explaining with examples may include a method (UL) in which an STA MLD transmits a TID-to-link element including information on a TID to which MU EDCA is applied and a link on which the TID operates to an AP MLD, and a method (DL) in which the AP MLD transmits the TID-to-link element including the information to the STA MLD.

[0205] Example 1

[0206] Example 1 relates to a method of transmitting information regarding which TID among the TIDs assigned to a link is to have MU EDCA applied when only one link performs MU EDCA operation based on a MU EDCA parameter set.

[0207] When MU EDCA operation is possible on one link between MLDs, a new field may be included in the TID-to-link element.

[0208] The new field proposed in this disclosure may be based on the format of the TID pair link element, and the value of the new field may be based on the value of the MU EDCA parameter set element. The TID pair link element including the new field related to MU EDCA may be defined as shown in FIG. 12(a) or FIG. 12(b).

[0209] As an example of this disclosure, as shown in FIG. 12(a), the presence or absence of a link on which MU EDCA operates may be indicated by the MU EDCA presence sub-field included in the TID pair link mapping control field of the TID pair link element.

[0210] As an example, when the value of the MU EDCA presence sub-field is 1 (or 0), the TID pair link element may have a MU EDCA mapping field. The MU EDCA mapping field may include a link ID ("Link ID for MU EDCA") sub-field for indicating the ID of the link on which MU EDCA operates (i.e., the link to which MU EDCA is applied). And the MU EDCA mapping field may include a TID for MU EDCA sub-field for indicating, in a bitmap, the TID that applies MU EDCA to the link.

[0211] The "Link ID for MU EDCA" sub-field may have a size of 4 bits for indicating the Link ID. The "TID for MU EDCA" sub-field may have a size of 8 bits (i.e., 1 octet) for indicating, in a bitmap, the presence or absence of application of each of the MU EDCA from TID 0 to TID 7. In order to align the length of the MU EDCA mapping field to an octet, 4 bits of the MU EDCA mapping field may be reserved.

[0212] As an example, Fig. 12(a) shows a case where the link for performing MU EDCA is Link 0, and the ACs to which MU EDCA is applied are the ACs corresponding to TIDs 0, 1, 2, and 3. For example, the "Link ID for MU EDCA" subfield may indicate the ID of the link ("0000"), and the "TID for MU EDCA" subfield may be set to "11110000" to indicate TIDs 0, 1, 2, and 3. At this time, the value of the MU EDCA presence field in the TID-to-link mapping control field may be set to 1.

[0213] As an example of the present disclosure, as shown in Fig. 12(b), the presence or absence of the link on which MU EDCA operates may be indicated by the MU EDCA presence subfield included in the TID-to-link mapping control field of the TID-to-link element.

[0214] As an example, when the value of the MU EDCA presence subfield is 1 (or 0), the TID-to-link element may have a MU EDCA mapping field. The MU EDCA mapping field may include a link ("Link for MU EDCA Indicator") subfield for a MU EDCA indicator that indicates the link on which MU EDCA operates in a bitmap.

[0215] Here, similar to Fig. 12(a), the MU EDCA mapping field may include a TID ("TID for MU EDCA") subfield for MU EDCA to represent the TIDs to which MU EDCA is applied on the link.

[0216] The "Link for MU EDCA Indicator" subfield may have a size of 16 bits (i.e., 2 octets) to indicate the maximum number of links that the MLD has. The "TID for MU EDCA" subfield may have a size of 8 bits (i.e., 1 octet) to indicate, in a bitmap, the presence or absence of the application of MU EDCA for TIDs 0 to TID 7, similar to that in Fig. 12(a).

[0217] The Link for MU EDCA Indicator subfield has a size of 16 bits (2 octets) to represent the maximum number of links that the MLD has in 11be. The TID for MU EDCA field has a size of 8 bits (1 octet) to represent, in a bitmap, the presence or absence of the application of MU EDCA for TIDs 0 to TID 7, similar to that in Fig. 1.

[0218] As an example, Fig. 12(b) illustrates a case where the link performing MU EDCA is Link 0 and the ACs to which MU EDCA is applied are the ACs corresponding to TIDs 0, 1, 2, and 3. For example, the "Link ID for MU EDCA indicator" subfield may indicate the ID of the link ("1000000000000000"), and the "TID for MU EDCA" subfield may be set to "11110000" to indicate TIDs 0, 1, 2, and 3. At this time, the MU EDCA presence field value in the TID-to-link mapping control field may be set to 1.

[0219] Example 2

[0220] Example 1 relates to a method of transmitting information regarding which TID among the TIDs assigned to a link should have MU EDCA applied when one or more links perform MU EDCA operations based on an MU EDCA parameter set.

[0221] When MU EDCA operation is possible on one or more links between MLDs, a new field may be included in the TID pair link element.

[0222] The new field proposed in this disclosure may be based on the format of the TID pair link element, and the value of the new field may be based on the value of the MU EDCA parameter set element. The TID pair link element including the new field related to MU EDCA may be defined as shown in (a) of FIG. 13, (b) of FIG. 13, or (c) of FIG. 13.

[0223] As shown in (a) of FIG. 13, when MU EDCA operation is applied to one or more links, the TID pair link element can indicate the presence or absence of the link where MU EDCA operates in the MU EDCA presence subfield within the TID pair link mapping control field.

[0224] As an example, when the MU EDCA presence subfield value is set to 1, the TID pair link element may include an MU EDCA mapping field. The MU EDCA mapping field can indicate the ID of the link to which MU EDCA is applied in the Link ID for MU EDCA subfield.

[0225] And the MU EDCA mapping field may include a TID for MU EDCA on Link N (N = 0, 1,..., 15) subfield that indicates, in a bitmap, the TIDs for which MU EDCA is applied to each link.

[0226] The name of the "Link ID for MU EDCA" subfield may be the same as the name of the corresponding field shown in Fig. 12(a). However, different from the field shown in Fig. 12(a), the "Link ID for MU EDCA" subfield shown in Fig. 13(a) can indicate the Link ID to which MU EDCA is applied in an array form. Thereby, the length of the "Link ID for MU EDCA" subfield shown in Fig. 13(a) may be variable. For example, the length of the "Link ID for MU EDCA" subfield is [m / 8] (m = 4 bits * number of Link IDs) and may have a maximum of 64 bits (8 octets).

[0227] The "TID for MU EDCA on Link N" subfield can associate the Link ID indicated in an array form with Link N (N = 0, 1,... 15). Thereby, the "TID for MU EDCA on Link N" subfield can indicate, in a bitmap, information regarding the presence or absence of MU EDCA application for TID 0 to TID 7 on each link and may have a size of 8 bits (1 octet).

[0228] The maximum length that the MU EDCA mapping field can have is 192 bits (i.e., 24 octets). Here, the number of Link IDs indicated by the "Link ID for MU EDCA" subfield and the number of "TID for MU EDCA on Link N" subfields may be the same.

[0229] As an example, as shown in Fig. 13(a), when MU EDCA is applied to one Link ID, the "Link ID for MU EDCA" sub-field may have a length of 8 bits (1 octet). And for the "Link ID for MU EDCA" sub-field, the values of the 5th to 8th bits may be set to 0. This means Link 0, but the "TID for MU EDCA on Link 0" sub-field may not be included in the TID-to-link element.

[0230] In the case described above, when Link 0 is indicated as one Link ID, the "Link ID for MU EDCA" sub-field value having a length of 8 bits (1 octet) may have "0000000". And the TID-to-link element may include one "TID for MU EDCA Link 0" sub-field.

[0231] As an example, assume that when MU EDCA is applied to Link 0 and Link 15, the TIDs to which MU EDCA is applied on Link 0 correspond to TIDs 0 and 1, and the TIDs to which MU EDCA is applied on Link 15 correspond to TIDs 0, 1, 2, and 3. At this time, the value of the MU EDCA presence field in the TID-to-link mapping control field may be set to 1. And since the "Link ID for MU EDCA" sub-field indicates the links in array form, it may have the values of "0000" and "1111". To indicate the information of the TIDs to which MU EDCA is applied on each link, the "TID for MU EDCA on Link 0" sub-field value may be set to "11000000", and the "TID for MU EDCA on Link 15" sub-field value may be set to "11110000".

[0232] As yet another example of the present disclosure, as shown in FIG. 13(b), when MU EDCA operation is applied to one or more links, the presence or absence of the links on which MU EDCA operates may be indicated by the MU EDCA presence subfield within the TID pair link mapping control field of the TID pair link element. As an example, when the value of the MU EDCA presence subfield is 1 (or 0), the TID pair link element may have a MU EDCA mapping field.

[0233] The MU EDCA mapping field may include a "Link for MU EDCA Indicator" subfield that indicates the links on which MU EDCA operates in a bitmap. It may include a "TID for MU EDCA on Link N (N = 0, 1,..., 15)" subfield that indicates in a bitmap the TIDs that apply MU EDCA to each link.

[0234] Similar to FIG. 12(b), the "Link for MU EDCA Indicator" subfield may have a size of 10 bits (2 octets) to represent the maximum number of links that the MLD can have.

[0235] The "TID for MU EDCA Link N" subfield can indicate the TID information to which MU EDCA is applied on the link indicated by the "Link for MU EDCA Indicator" subfield as being a link on which MU EDCA operates. That is, the number of 1s in the "Link for MU EDCA Indicator" subfield and the number of "TID for MU EDCA on Link N" subfields may be the same.

[0236] As an example, assume that when MU EDCA is applied to Link 0 and Link 15, the TIDs to which MU EDCA is applied on Link 0 correspond to TID 0 and 1, and the TIDs to which MU EDCA is applied on Link 15 correspond to TID 0, 1, 2, and 3. At this time, the value of the MU EDCA presence field in the TID-to-link mapping control field may be set to 1. And since the "Link for MU EDCA Indicator" subfield indicates the links in bitmap form, it may have a value of "1000000000000001". To indicate the information of the TIDs to which MU EDCA is applied on each link, the "TID for MU EDCA on Link 0" subfield value may be set to "11000000", and the "TID for MU EDCA on Link 15" subfield value may be set to "11110000".

[0237] As still another example of the present disclosure, as shown in FIG. 13(c), when MU EDCA operations are performed on one or more links, the presence or absence of the links on which MU EDCA operates can be indicated by the MU EDCA presence subfield in the TID-to-link mapping control field of the TID-to-link element. If the value of the MU EDCA presence subfield is 1 (or 0), the TID-to-link element may have an MU EDCA mapping field.

[0238] The MU EDCA mapping field may include an MU EDCA indicator subfield and a "Link for MU EDCA on TID n" subfield, and may have a maximum length of 17 octets.

[0239] The link to which MU EDCA is applied can be indicated by a value of 1 in the subfield corresponding to each TID. Here, the presence or absence of the subfield corresponding to each TID is indicated by 1 or 0 by the MU EDCA indicator field, and it may have a length of 1 octet to indicate TIDs 0 to TID 7 in a bitmap. When the MU EDCA indicator field value is set to 1, it can indicate that the subfield of the corresponding TID exists.

[0240] That is, when a specific bit of the bitmap corresponding to TIDs 0 to TID 7 in the MU EDCA indicator subfield is set to 1, it can mean that the corresponding TID is the TID to which MU EDCA is applied. The subfield of the corresponding TID may be located after the "Link for MU EDCA on TID n" subfield.

[0241] In order for each TID n in each "Link for MU EDCA on TID n" subfield to indicate the link to which MU EDCA is applied, each link has a value of 1 or 0 in the corresponding bitmap, and each subfield may have a length of 2 octets to indicate all links in a bitmap.

[0242] As an example, assume that the TIDs to which MU EDCA is applied are TIDs 0, 1, 2, 3, and MU EDCA operates on Links 0, 1, 2, 13, 14, 15. As shown in Fig. 13(c), the MU EDCA indicator subfield can indicate that MU EDCA is applied to TIDs 0, 1, 2, 3 with a value of "11110000".

[0243] Also, as shown in Fig. 13(c), a "Link for MU EDCA on TID n" subfield corresponding to a TID n having a value of 1 may exist. At this time, the "Link for MU EDCA on TID 0" subfield, the "Link for MU EDCA on TID 1" subfield, the "Link for MU EDCA on TID 2" subfield, and the "Link for MU EDCA on TID 3" subfield may be arranged in this order after the "MU EDCA Indicator" subfield.

[0244] And the MU EDCA mapping field has a total length of 9 octets. By setting the "Link for MU EDCA on TID 0" subfield value to "1110000000000111", it may be indicated that TID 0 to which MU EDCA is applied operates on Links 0, 1, 2, 13, 14, and 15. The other "Link for MU EDCA on TID 1" subfield, "Link for MU EDCA on TID 2" subfield, and "Link for MU EDCA on TID 3" subfield may also have the same value (i.e., "1110000000000111"). Thereby, it may be indicated that the TID to which MU EDCA is applied operates on Links 0, 1, 2, 13, 14, and 15.

[0245] Fig. 13(c) shows a case where the TIDs to which MU EDCA is applied on Links 0, 1, 2, 3, 13, 14, and 15 are the same. However, this is only one example, and the TIDs to which MU EDCA is applied on each link may be different. For example, the TIDs to which MU EDCA is applied on Link 0 and Link 1 may be TID 0 and TID 3, and the TIDs to which MU EDCA is applied on Link 3 may be TID 1 and TID 2.

[0246] Example 3

[0247] Embodiment 3 relates to a method of transmitting information regarding which TID among the TIDs assigned to a link is to be applied with MU EDCA when MU EDCA is applied only to one link based on the LL MU EDCA parameter set.

[0248] When it is assumed that MU EDCA operation is possible on one link between MLDs, a new field may be added to the TID - to - link element.

[0249] The new field described in the present disclosure is based on the format of the "TID - to - link element", and the new field value may be based on the value of the new LL (Low Latency) MU EDCA parameter set element. The LL MU EDCA parameter set means an EDCA parameter set for LL data.

[0250] The LL MU EDCA parameter set element of the present disclosure may be defined as shown in FIGS. 14(a) and (b). The name and the length of each field of the LL MU EDCA parameter set element shown in FIG. 14(a) may vary.

[0251] As shown in FIG. 14(a), after the QoS information field of the LL MU EDCA parameter set element, a total of eight 3 - octet - long LL MU TID n parameter record fields corresponding to TID 0 to TID 7 may be located.

[0252] Each LL MU TID n parameter record field may be configured as shown in FIG. 14(b). At this time, each of the LL MU TID n parameter record fields may be configured to be the same as the MU AC parameter record field format field in the above - described MU EDCA parameter set element.

[0253] As an example of the present disclosure, as shown in FIG. 14(c), the TID-to-link element can indicate the presence or absence of a link on which MU EDCA operates in the LL MU EDCA presence subfield within the TID-to-link mapping control field.

[0254] As an example, when the value of the LL MU EDCA presence subfield is 1 (or 0), the TID-to-link element may have an LL MU EDCA mapping field. The LL MU EDCA mapping field may include a "Link ID for LL MU EDCA" subfield that indicates the link on which MU EDCA operates with a Link ID. Further, the LL MU EDCA mapping field may include a "TID for LL MU EDCA" subfield that indicates, in a bitmap, the TIDs to which MU EDCA is applied to the link.

[0255] The "Link ID for LL MU EDCA" subfield may have a size of 4 bits to indicate the Link ID. The "TID for LL MU EDCA" subfield may have a size of 8 bits (i.e., 1 octet) to indicate, in a bitmap, the presence or absence of application of MU EDCA for TIDs 0 to 7. The LL MU EDCA mapping field may have 4 bits reserved for setting the length of the LL MU EDCA mapping field in octet units.

[0256] As an example, assume that when MU EDCA operates / applies to Link 0, the ACs to which MU EDCA is applied are the ACs corresponding to TIDs 0, 1, 2, and 3. Therefore, the value of the LL MU EDCA presence field within the TID-to-link mapping control field may be indicated as 1. Then, the value of the "Link ID for LL MU EDCA" subfield may be set to "0000", and the "TID for LL MU EDCA" field may have a value of "11110000" to indicate TIDs 0, 1, 2, and 3.

[0257] As an example of the present disclosure, as shown in FIG. 14(d), the TID pair link element may include an LL MU EDCA presence subfield. The TID pair link element may have the same LL MU EDCA presence subfield as that shown in FIG. 14(c).

[0258] The LL MU EDCA mapping field may include a "Link for LL MU EDCA Indicator" that indicates the link on which MU EDCA operates based on a bitmap. Similar to FIG. 14(c), the LL MU EDCA mapping field may include a "TID for LL MU EDCA" subfield for indicating the TID to which MU EDCA is applied on the link.

[0259] The "Link for LL MU EDCA Indicator" subfield may have a size of 16 bits (2 octets) to indicate the number of the maximum links that the MLD has. The "TID for LL MU EDCA" field may have a size of 8 bits (1 octet) to indicate the presence or absence of the application of MU EDCA for TID 0 to TID 7 based on a bitmap.

[0260] As an example, assume that when MU EDCA operates / applies to Link 0, the ACs to which MU EDCA is applied are the ACs corresponding to TID 0, 1, 2, 3. Therefore, the value of the LL MU EDCA presence field in the TID pair link mapping control field may be indicated as 1. And the value of the bitmap-based "Link ID for LL MU EDCA indicator" subfield is set to "1000000000000000", and the "TID for LL MU EDCA" field may have a value of "11110000" to indicate TID 0, 1, 2, 3.

[0261] Example 4

[0262] Embodiment 4 relates to a method of transmitting information regarding which of the TIDs assigned to a link is to have MU EDCA applied when MU EDCA is applied only to one or more links based on an LL MU EDCA parameter set.

[0263] When it is assumed that MU EDCA operation is possible on one or more links between MLDs, the TID-to-link element may include a new field. The new field described in the present disclosure is based on the format of the "TID-to-link element", and the new field value may be based on the value of a new LL (Low Latency) MU EDCA parameter set element. The LL MU EDCA parameter set means an EDCA parameter set for LL data. The LL MU EDCA parameter set means an EDCA parameter set for LL data.

[0264] The LL MU EDCA parameter set elements of the present disclosure may be defined as shown in FIGS. 14(a) and (b). The names of the LL MU EDCA parameter set elements and the lengths of each field shown in FIG. 14(a) may vary.

[0265] The LL MU EDCA parameter set elements shown in FIG. 14(a) and each LL MU TID n parameter record fields shown in FIG. 14(b) have been described in Embodiment 3, and the overlapping descriptions are omitted.

[0266] As shown in FIG. 15(a), when MU EDCA operation is applied to one or more links, the TID-to-link element can indicate the presence or absence of the link on which MU EDCA operates in the LL MU EDCA presence subfield within the TID-to-link mapping control field. When the value of the LL MU EDCA presence subfield is 1, the TID-to-link element may have an LL MU EDCA mapping field.

[0267] The LL MU EDCA mapping field may indicate the ID of the link on which MU EDCA operates in the "Link ID for LL MU EDCA" subfield. The LL MU EDCA mapping field may include a "TID for LL MU EDCA on Link N (N = 0, 1,..., 15)" subfield that indicates, based on a bitmap, the TIDs for applying MU EDCA to each link.

[0268] The "Link ID for LL MU EDCA" subfield can indicate the Link ID in array form. Different from the "Link ID for LL MU EDCA" subfield having a length of 4 bits in Fig. 14(c), the "Link ID for LL MU EDCA" subfield may have a variable value.

[0269] At this time, the length of the "Link ID for LL MU EDCA" subfield is [m / 8] (m = 4 bits * number of Link IDs) and may have a maximum of 64 bits (8 octets). The "TID for LL MU EDCA on Link N" subfield can associate the Link ID indicated in array form with Link N (N = 0, 1,..., 15). Thereby, the "TID for LL MU EDCA on Link N" subfield indicates, based on a bitmap, information regarding the presence or absence of the application of TIDs 0 to TID 7 on each link and may have a size of 8 bits (1 octet).

[0270] Therefore, the maximum length that the LL MU EDCA mapping field can have is 192 bits (24 octets). Here, the number of Link IDs indicated by the "Link ID for LL MU EDCA" subfield and the number of "TID for LL MU EDCA on Link N" subfields may be the same.

[0271] As shown in Fig. 15(a), when the "Link ID for LL MU EDCA" subfield has one Link ID, the field may have a length of 8 bits (1 octet). And the 5-8 bit value of the field may be set to 0.

[0272] This means Link 0, but the "TID for LL MU EDCA on Link 0" subfield may not be included in the TID pair link element. As an example, when one Link ID indicates Link 0, the "Link ID for LL MU EDCA" subfield value with a length of 8 bits (1 octet) may have "0000000", and the TID pair link element may include one "TID for LL MU EDCA Link 0" subfield.

[0273] As an example, assume that when MU EDCA is applied to Link 0 and Link 15, the TIDs to which MU EDCA is applied on each link correspond to TID 0 and 1 on Link 0, and TID 0, 1, 2, and 3 on Link 15. Therefore, the value of the LL MU EDCA presence field in the TID pair link mapping control field may be set to 1. The "Link ID for LL MU EDCA" subfield may be set to "0000" and "1111". To indicate the information of the TIDs to which MU EDCA is applied on each link, the "TID for LL MU EDCA on Link 0" subfield value may be set to "11000000", and the "TID for LL MU EDCA on Link 15" subfield value may be set to "11110000".

[0274] As an example of the present disclosure, as shown in Fig. 15(b), the TID pair link element may include an LL MU EDCA presence subfield. The LL MU EDCA presence subfield of the TID pair link element may be the same as the TID pair link element shown in Fig. 15(a) that includes the LL MU EDCA presence subfield.

[0275] The LL MU EDCA mapping field may include a "Link for LL MU EDCA Indicator" subfield that indicates, based on a bitmap, the links on which MU EDCA operates. It may include a "TID for LL MU EDCA on Link N (N = 0, 1,..., 15)" subfield that indicates, in a bitmap, the TIDs for which MU EDCA is applied on the links indicated by the "Link for LL MU EDCA Indicator" subfield as the links on which MU EDCA operates.

[0276] The "Link for LL MU EDCA Indicator" subfield may have a size of 16 bits (2 octets) to represent the maximum number of links that the MLD may have. The "TID for LL MU EDCA Link N" subfield can indicate the TID information to which MU EDCA is applied on the link indicated by the "Link for LL MU EDCA Indicator" subfield as the link on which MU EDCA operates.

[0277] That is, the number of 1s in the "Link for LL MU EDCA Indicator" subfield and the number of "TID for LL MU EDCA on Link N" subfields may be the same.

[0278] As an example, when MU EDCA is applied to Link 0 and Link 15, assume that the TIDs to which MU EDCA is applied for each link correspond to TID 0 and 1 for Link 0, and TID 0, 1, 2, and 3 for Link 15. Therefore, the value of the LL MU EDCA presence field in the TID-to-link mapping control field may be set to 1. The "Link for LL MU EDCA Indicator" subfield may have "1000000000000001". To indicate the information of the TIDs to which MU EDCA is applied for each link, the "TID for LL MU EDCA on Link 0" subfield value may be set to "11000000", and the "TID for LL MU EDCA on Link 15" subfield value may be set to "11110000".

[0279] As yet another example of the present disclosure, as shown in FIG. 15(c), the TID-to-link element may include an LL MU EDCA presence subfield. The LL MU EDCA presence subfield may be the same as the LL MU EDCA presence subfield shown in FIG. 15(a).

[0280] The LL MU EDCA mapping field may include an LL MU EDCA indicator subfield and a "Link for LL MU EDCA on TID n" subfield, and may have a maximum length of 17 octets.

[0281] The link on which MU EDCA operates may be indicated by a value of 1 in the subfield corresponding to each TID. Here, the presence or absence of the subfield corresponding to each TID may be indicated by 1 (i.e., present) and 0 (i.e., absent) in the "LL MU EDCA indicator subfield". The "LL MU EDCA indicator subfield" may have a length of 1 octet to indicate TIDs 0 to TID 7 based on a bitmap.

[0282] That is, when the bitmap corresponding to TIDs 0 to 7 in the LL MU EDCA indicator subfield has a value of 1, it can be meant that the TID is a TID to which MU EDCA is applied. And the "Link for LL MU EDCA on TID n" subfield, which is the subfield corresponding to this TID, may be located after the LL MU EDCA indicator subfield.

[0283] In order for the TID n in each "Link for LL MU EDCA on TID n" subfield to indicate a link to which MU EDCA is applied, the bitmap corresponding to each link may have a value of 1 or 0. In order to indicate all links based on the bitmap, each subfield may have a length of 2 octets.

[0284] As an example, assume that the TIDs to which MU EDCA is applied are TIDs 0, 1, 2, and 3, and this is the case when operating on Links 0, 1, 2, 13, 14, and 15. At this time, the LL MU EDCA indicator subfield value is set to "11110000", which means that MU EDCA is applied to TIDs 0, 1, 2, and 3.

[0285] Also, a "Link for LL MU EDCA on TID n" subfield corresponding to the TID n having a value of 1 may exist. In the LL MU EDCA mapping field, the "Link for LL MU EDCA on TID 0" subfield, the "Link for LL MU EDCA on TID 1" subfield, the "Link for LL MU EDCA on TID 2" subfield, and the "Link for LL MU EDCA on TID 3" subfield may be arranged in this order after the LL MU EDCA indicator subfield.

[0286] The LL MU EDCA mapping field may have a total length of 9 octets. The "Link for LL MU EDCA on TID 0" sub-field value may be set to "1110000000000111". This means that TID 0 to which MU EDCA is applied operates on Links 0, 1, 2, 13, 14, and 15. At this time, the "Link for LL MU EDCA on TID 1" sub-field, the "Link for LL MU EDCA on TID 2" sub-field, and the "Link for LL MU EDCA on TID 3" sub-field may also have the same value. This can mean that the TIDs to which MU EDCA is applied operate on Links 0, 1, 2, 13, 14, and 15.

[0287] In the case of (c) in FIG. 15, the case where the TIDs to which MU EDCA is applied are the same on Links 0, 1, 2, 3, 13, 14, and 15 is illustrated, but it is not limited thereto. The TIDs to which MU EDCA is applied may be different on each link. For example, the TIDs to which MU EDCA is applied on Links 0 and 1 may be TID 0 and TID 3, and the TIDs to which MU EDCA is applied on Link 3 may be TID 1 and TID 2.

[0288] Example 5

[0289] Example 5 relates to a method of instructing MU EDCA applied to the TID of a link using a new element.

[0290] Specifically, in Examples 1 to 4, the case where the MU EDCA application information included therein is signaled together when the TID-to-link mapping element is signaled has been described. Example 5 relates to a method of transmitting and receiving information on the applied MU EDCA among the TIDs mapped on each link using an element separate from the TID-to-link mapping element.

[0291] As shown in FIGS. 16(a) and 16(b), the novel element proposed in the present disclosure may be based on the MU EDCA parameter set element. When there are LL MU EDCA parameter set elements disclosed in Example 3 and Example 4, the novel element may be based on the LL MU EDCA parameter set. Here, the LL EDCA parameter set means the EDCA parameter set for LL data and may be expressed by various names.

[0292] The novel element of the present disclosure may be transmitted separately from the TID-to-link mapping element. As another example, for use together with the TID-to-link mapping element, the novel element may be transmitted positioned after order 4 (e.g., order 5) on the order field of the TID-to-link mapping request / response frame action field. The names of the novel LL EDCA mapping elements shown in FIGS. 16(a) and 16(b) and the names of the fields included therein may be embodied in various ways.

[0293] The novel LL EDCA mapping element based on the elements defined in Example 1 and Example 3 may be configured as shown in FIGS. 16(a) and 16(b). The LL EDCA mapping element shown in FIG. 16(a) can indicate the link on which MU EDCA operates with a Link ID, and the LL EDCA mapping element shown in FIG. 16(b) can indicate the link on which MU EDCA operates with a bitmap.

[0294] As an example, the LL EDCA control field of the LL EDCA mapping element may include a direction subfield, a mapping switch time presence subfield, an expected duration presence subfield, and an LL EDCA presence subfield.

[0295] The direction subfield can indicate UL or DL (or, P2P), the mapping switch time presence subfield indicates the presence or absence of the mapping switch time field, the expected interval presence subfield indicates the presence or absence of the expected interval field, and the LL EDCA presence subfield can indicate the presence or absence of the LL EDCA mapping field.

[0296] A mapping switch time subfield and an expected interval presence subfield exist on the LL EDCA control field, and these subfields can serve the role of timers used when the TID to which MU EDCA is applied in the TID pair link mapping subfield operates on the link.

[0297] The LL EDCA mapping field in (a) of FIG. 16 may include a "Link ID for LL EDCA" subfield indicated by the link ID on which MU EDCA operates. Also, the LL EDCA mapping field may include a "TID for LL EDCA" subfield that indicates, in a bitmap, the TIDs to which MU EDCA is applied to the link.

[0298] The "Link ID for LL EDCA" subfield may have a size of 4 bits to indicate the Link ID, and the "TID for LL EDCA" field may have a size of 8 bits (1 octet) to indicate, in a bitmap, the presence or absence of the application of MU EDCA for TID 0 to TID 7. To align the length of the LL EDCA mapping field to an octet, the LL EDCA mapping field may have 4 reserved bits.

[0299] In (b) of FIG. 16, the LL EDCA mapping field may include a "Link for LL EDCA Indicator" subfield in a format that indicates, in a bitmap, the links on which MU EDCA operates. The LL EDCA mapping field may include a "TID for LL EDCA" subfield for indicating the TID to which MU EDCA is applied on the link.

[0300] The "Link for LL EDCA Indicator" subfield may have a size of 16 bits (2 octets) to represent the maximum number of links that the MLD has. The "TID for LL EDCA" field may have a size of 8 bits (1 octet) to indicate, in a bitmap, the presence or absence of the application of MU EDCA for TIDs 0 to 7.

[0301] As an example, assume that when MU EDCA is applied to Link 0, the ACs to which MU EDCA is applied are the ACs corresponding to TIDs 0, 1, 2, and 3. At this time, as shown in (a) and (b) of FIG. 16, the value of the LL EDCA presence field in the LL EDCA control field may be indicated as 1. However, as shown in (a) of FIG. 16, the value of the "Link ID for LL EDCA" subfield is set to "0000", and as shown in (b) of FIG. 16, the value of the "Link for LL EDCA indicator" subfield based on the bitmap may be set to "1000000000000000". To indicate TIDs 0, 1, 2, and 3, the "TID for LL EDCA" field value may be set to "11110000".

[0302] The new LL EDCA mapping element based on the elements defined in Example 2 and Example 4 may be configured as shown in (a), (b), and (c) of FIG. 17.

[0303] (a) of FIG. 17 illustrates a method of indicating a link to which MU EDCA is applied by a Link ID, (b) of FIG. 17 illustrates a method of indicating a link to which MU EDCA is applied by a bitmap, and (c) of FIG. 17 can illustrate a method of indicating a link in a field corresponding to each TID by indicating a TID to which MU EDCA is applied by a bitmap.

[0304] The configuration of the LL EDCA control field of the element and the mapping switch time field / predicted interval field have been described above, and duplicate explanations are omitted.

[0305] In the LL EDCA mapping field in (a) of FIG. 17, the ID of the link on which MU EDCA operates may be indicated by the "Link ID for LL EDCA" subfield. The LL EDCA mapping field may include a "TID for LL EDCA on Link N (N = 0, 1,..., 15)" subfield that indicates, by a bitmap, the TID that applies MU EDCA to each link.

[0306] Since the "Link ID for LL EDCA" subfield indicates the Link ID in an array form, it may have a variable length. At this time, the length of the field is [m / 8] (m = 4 bits * the number of Link IDs), and may have a maximum of 64 bits (8 octets).

[0307] Therefore, the "TID for LL EDCA on Link N" subfield can associate the Link ID indicated in an array form with Link N (N = 0, 1,..., 15). Thereby, information regarding the presence or absence of the application of MU EDCA for TIDs 0 to TID 7 on each link may be indicated by a bitmap and may have a size of 8 bits (1 octet). Therefore, the maximum length that the LL EDCA mapping field can have is 192 bits (24 octets).

[0308] Here, the number of Link IDs indicated by the "Link ID for LL EDCA" subfield and the number of the "TID for LL EDCA on Link N" subfield may be the same.

[0309] In FIG. 17(a), when the "Link ID for LL EDCA" subfield has one Link ID, the field may have a length of 8 bits (1 octet), and the 5th to 8th bit values of the field may be set to 0. This means Link 0, but the "TID for LL EDCA on Link 0" subfield may not be included in the TID pair link element. In the above case, when one Link ID indicates Link 0, the "Link ID for LL EDCA" subfield having a length of 8 bits (1 octet) may have "0000000", and the TID pair link element may include one "TID for LL EDCA Link 0" subfield.

[0310] In FIG. 17(b), the LL EDCA mapping field may include a "Link for LL EDCA Indicator" subfield that indicates the links on which MU EDCA operates in a bitmap.

[0311] It may include a "TID for LL EDCA on Link N (N = 0, 1,..., 15)" subfield that indicates the TIDs for applying MU EDCA to each link in a bitmap. The "Link for LL EDCA Indicator" subfield may have a size of 16 bits (2 octets) to represent the maximum number of links that the MLD can have.

[0312] The "TID for LL EDCA Link N" subfield can indicate the TID information to which MU EDCA on the link indicated by the "Link for LL EDCA Indicator" subfield is applied, i.e., the number of 1s in the "Link for LL EDCA Indicator" subfield and the number of the "TID for LL EDCA on Link N" subfield may be the same.

[0313] The LL EDCA mapping field in Fig. 17(c) may be composed of an LL EDCA indicator subfield and a "Link for LL EDCA on TID n" subfield, and may have a maximum length of 17 octets. The link on which MU EDCA operates may be indicated by a value of 1 within the subfield corresponding to each TID. Here, the presence or absence of the subfield corresponding to each TID may be indicated by 1 (i.e., present) or 0 (i.e., absent) in the LL EDCA Indicator subfield. The presence or absence of the subfield corresponding to each TID may have a length of 1 octet to indicate TIDs 0 to 7 in a bitmap.

[0314] That is, when the bitmap corresponding to TIDs 0 to 7 in the LL EDCA indicator subfield has a value of 1, it can mean that the TID is the TID to which MU EDCA is applied. And the subfield of the corresponding TID may have the "Link for LL EDCA on TID n" subfield located after the LL EDCA Indicator subfield.

[0315] For each "Link for LL EDCA on TID n" subfield, the TID n therein indicates the link to which MU EDCA is applied. For this purpose, the bitmap corresponding to each link may have a value of 1 or 0, and each subfield may have a length of 2 octets to indicate all the links in a bitmap.

[0316] As an example, assume that when MU EDCA is applied to Link 0 and Link 15, the TIDs to which MU EDCA is applied on Link 0 correspond to TID 0 and 1, and the TIDs to which MU EDCA is applied on Link 15 are TID 0, 1, 2, and 3.

[0317] At this time, as shown in FIGS. 17(a) and 17(b), the value of the LL EDCA presence field in the LL EDCA control field may be set to 1. However, since the link ID is indicated in an array form in FIG. 17(a), the "Link ID for LL EDCA" subfield value may be set to "0000" and "1111". In FIG. 17(b), since the link is indicated by a bitmap, the "Link for LL EDCA Indicator" subfield value may be set to "1000000000000001".

[0318] To indicate the information of the TIDs to which MU EDCA is applied on each link, the "TID for LL EDCA on Link 0" subfield value in FIGS. 17(a) and 17(b) may be set to "11000000", and the "TID for LL EDCA on Link 15" subfield value may be set to "11110000".

[0319] As still another example of the present disclosure, assume that the TIDs to which MU EDCA is applied are TID 0, 1, 2, and 3, and these operate on Link 0, 1, 2, 13, 14, and 15.

[0320] At this time, in FIG. 17(c), the value of the "LL EDCA Indicator" subfield is set to "11110000", which can indicate that MU EDCA is applied to TID 0, 1, 2, and 3.

[0321] Also, a "Link for LL EDCA on TID n" subfield corresponding to TID n having a value of 1 may exist in the LL EDCA mapping field. As shown in FIG. 17(c), after the LL EDCA indicator subfield, a "Link for LL EDCA on TID 0" subfield, a "Link for LL EDCA on TID 1" subfield, a "Link for LL EDCA on TID 2" subfield, and a "Link for LL EDCA on TID 3" subfield may be arranged.

[0322] And, as shown in FIG. 17(c), the LL EDCA mapping field may have a total length of 9 octets. The "Link for LL EDCA on TID 0" subfield value may be set to "1110000000000111", and it may be indicated that TID 0 to which MU EDCA is applied operates on Links 0, 1, 2, 13, 14, and 15.

[0323] Since the other "Link for LL EDCA on TID 1" subfield, "Link for LL EDCA on TID 2" subfield, and "Link for LL EDCA on TID 3" subfield also have the same value, it may be indicated that the TIDs to which MU EDCA is applied operate on Links 0, 1, 2, 13, 14, and 15.

[0324] FIG. 17(c) illustrates the case where the TIDs to which MU EDCA is applied on Links 0, 1, 2, 3, 13, 14, and 15 are the same, but the TIDs to which MU EDCA is applied on each link may be different. For example, the TIDs to which MU EDCA is applied on Links 0 and 1 may be TID 0 and TID 3, and the TIDs to which MU EDCA is applied on Link 3 may be TID 1 and TID 2.

[0325] Example 6

[0326] Embodiment 6 relates to a method of indicating whether to use an MU EDCA parameter set based on an AC. Specifically, Embodiments 1 to 5 relate to a method of instructing a TID that operates based on an (LL)MU EDCA parameter set. Embodiment 6 relates to a method of instructing an AC that uses an (LL)MU EDCA parameter set.

[0327] The method of instructing an AC that uses an (LL)MU EDCA parameter set may be based on the method according to Embodiments 1 to 5. Thereby, the prerequisites and rules of the TID pair link mapping to which the method proposed in Embodiment 6 is applied may be the same as the prerequisites and rules described in Embodiments 1 to 5.

[0328] As an example of the present disclosure, FIG. 18(a) illustrates a TID pair link element that indicates a Link ID and an AC when MU EDCA operates only on one link. Instead of the "TID for MU EDCA" subfield based on the TID pair link element illustrated in FIG. 12(a), an "AC for MU EDCA" subfield may be used.

[0329] As an example, the "AC for MU EDCA" subfield has a length of 4 bits, and each bit can mean AC_BK, AC_BE, AC_VI, and AC_VO. At this time, if the value of each bit is set to 1, it can mean that the MU EDCA parameter set is applied to the AC.

[0330] Instead of the "TID for LL MU EDCA" subfield in FIG. 14(c) and the "TID for LL EDCA" subfield in FIG. 16(a), an "AC for LL(MU)EDCA" subfield may be applied. The MU EDCA mapping field in FIG. 12(a), the LL MU EDCA mapping field in FIG. 14(c), and the LL EDCA mapping field in FIG. 16(a) have a length of 2 octets, but the MU EDCA mapping field in FIG. 18(a) may have 1 octet.

[0331] Figure 18(b) illustrates the TID-to-link elements that indicate the link with AC and the bitmap when only MU EDCA operates on one link. As shown in Figure 18(b), based on the TID-to-link elements illustrated in Figure 12(b), the "AC for MU EDCA" subfield may be applied instead of the "TID for MU EDCA" subfield.

[0332] The "AC for MU EDCA" subfield has a length of 4 bits, and each bit can represent AC_BK, AC_BE, AC_VI, and AC_VO. At this time, if the value of each bit is set to 1, it can mean that the MU EDCA parameter set is applied to the corresponding AC.

[0333] As an example, instead of the "TID for LL MU EDCA" subfield in Figure 14(d) and the "TID for LL EDCA" subfield in Figure 16(b), the "AC for LL(MU)EDCA" subfield may be applied.

[0334] As an example, assume that when MU EDCA operates on Link 0 and the ACs to which MU EDCA is applied are AC_BK and AC_BE. As shown in Figures 18(a) and (b), the value of the MU EDCA presence field in the TID-to-link mapping control field may be set to 1.

[0335] Here, the value of the "Link ID for MU EDCA" subfield in Figure 18(a) may be set to "0000", and the value of the "Link for MU EDCA indicator" subfield that indicates the link based on the bitmap in Figure 18(b) may be set to "1000000000000000". To indicate AC_BK and AC_BE, the "AC for MU EDCA" field value may be set to "1100".

[0336] As yet another example of the present disclosure, FIG. 19(a) illustrates the case where the "AC for MU EDCA on Link n" subfield is applied instead of the "TID for MU EDCA on Link n" subfield illustrated in FIG. 13(a). Each of the "AC for MU EDCA on Link n" subfields has a length of 4 bits, and each bit can mean AC_BK, AC_BE, AC_VI, AC_VO. At this time, when the value of each bit is set to 1, it means that the MU EDCA parameter set is applied to the AC.

[0337] Instead of the "TID for LL MU EDCA on Link n" subfield in FIG. 15(a) and the "TID for LL EDCA on Link n" subfield in FIG. 16(a), the "AC for LL(MU)EDCA on Link n" subfield may be applied.

[0338] FIG. 19(b) illustrates the case where the "AC for MU EDCA on Link n" subfield is applied instead of the "TID for MU EDCA on Link n" subfield based on the TID pair link element illustrated in FIG. 13(b).

[0339] The "AC for MU EDCA on Link n" subfield has a length of 4 bits, and each bit can mean AC_BK, AC_BE, AC_VI, AC_VO. At this time, if the value of each bit is set to 1, the MU EDCA parameter set may be applied to the AC.

[0340] Instead of the "TID for LL MU EDCA on Link n" subfield in FIG. 15(b) and the "TID for LL EDCA on Link n" subfield in FIG. 17(b), the "AC for LL(MU)EDCA on Link n" subfield may be applied.

[0341] The MU EDCA mapping field in Fig. 13(b), the LL MU EDCA mapping field in Fig. 15(b), and the LL EDCA mapping field in Fig. 17(b) have 18 octets, while the MU EDCA mapping field in Fig. 18(a) may have 10 octets.

[0342] Fig. 19(c) illustrates a case where the "Link for MU EDCA on AC_BK (AC_BE, AC_VI, or AC_VO)" subfield is applied instead of the "Link for MU EDCA on TID n" subfield based on the TID-to-link element exemplified in Fig. 13(c).

[0343] At this time, the "MU EDCA Indicator" subfield has a length of 4 bits, and each bit can represent AC_BK, AC_BE, AC_VI, and AC_VO. At this time, if the value of each bit is set to 1, it means that the MU EDCA parameter set is applied to the corresponding AC.

[0344] Instead of the "Link for LL MU EDCA on TID n" subfield in Fig. 15(c) and the "Link for LL EDCA on TID n" subfield in Fig. 17(c), the "Link for LL(MU)EDCA on AC_BK (AC_BE, AC_VI, or AC_VO)" subfield may be applied.

[0345] As an example, assume that when MU EDCA is applied to both Link 0 and Link 15, the ACs to which MU EDCA is applied for each link correspond to AC_BK for Link 0 and AC_BK and AC_BE for Link 15. The value of the MU EDCA presence field in the TID-to-link mapping control field may be set to 1.

[0346] However, in Fig. 19(a), since the Link ID is indicated in an array form, the "Link ID for MU EDCA" subfield value may be set to "0000" and "1111". In Fig. 19(b), since the link is indicated by a bitmap, the "Link for MU EDCA Indicator" subfield value may be set to "1000000000000001". To indicate the information of the AC to which MU EDCA is applied for each link, the "AC for MU EDCA on Link 0" subfield value in Fig. 19(a) and Fig. 19(b) may be set to "1000", and the "AC for MU EDCA on Link 15" subfield value may be set to "1100". Accordingly, the length of the MU EDCA mapping field may be 2 octets in Fig. 19(a) and 3 octets in Fig. 19(b).

[0347] As yet another example of the present disclosure, the ACs to which MU EDCA is applied are AC_BK and AC_BE, assuming the case of operating on Links 0, 1, 2, 13, 14, and 15.

[0348] By setting the "MU EDCA Indicator" subfield value in Fig. 19(c) to "1100", it may be indicated that MU EDCA is applied to AC_BK and AC_BE.

[0349] Also, a "Link for MU EDCA on AC" subfield corresponding to the AC having a value of 1 may exist. As shown in Fig. 19(c), it may be located in the MU EDCA mapping field in the order of the "Link for MU EDCA on AC_BK" subfield and the "Link for MU EDCA on AC_BE" subfield after the "MU EDCA Indicator" subfield.

[0350] In FIG. 19(c), the MU EDCA mapping field may have a total length of 5 octets. By setting the "Link for MU EDCA on AC_BK" subfield value to "1110000000000111", it may be indicated that the AC_BK to which MU EDCA is applied operates on Links 0, 1, 2, 13, 14, and 15.

[0351] By having other "Link for MU EDCA on AC_BE" subfields have the same value, it may be indicated that the AC to which MU EDCA is applied operates on Links 0, 1, 2, 13, 14, and 15.

[0352] In FIG. 19(c), an example is illustrated where the ACs to which MU EDCA is applied on Links 0, 1, 2, 3, 13, 14, and 15 are the same, but the ACs to which MU EDCA is applied on each link may be different. For example, the ACs to which MU EDCA is applied on Links 0 and 1 may be set as AC_BK, and the TID to which MU EDCA is applied on Link 3 may be set as AC_BK and AC_BE.

[0353] The embodiments described above are those in which the components and features of the present disclosure are combined in a predetermined form. Each component or feature should be considered as optional unless specifically and explicitly mentioned. Each component or feature may be implemented in a form that does not combine with other components or features. Also, it is 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 other embodiments, or may be replaced with corresponding components or features of other embodiments. It is obvious that claims without an explicit citation relationship in the claims can be combined to form embodiments, or included as new claims by amendment after filing.

[0354] It will be apparent 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 construed in any way as restrictive, but should be considered exemplary. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and any changes within the equivalent scope of the present disclosure are included in the scope of the present disclosure.

[0355] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that cause a device or computer to perform operations according to the methods of various embodiments, and a non-transitory computer-readable medium on which such software or instructions are stored and executable on the device or computer. Instructions available for programming a processing system to perform the features described in the present disclosure may be stored on or in a storage medium or computer-readable storage medium, and the features described in the present disclosure may be implemented using a computer program product including such a storage medium. The storage medium can include, but is not limited to, high-speed random access memory such as DRAM, SRAM, DDR RAM, or other random access solid-state memory devices, and can include non-volatile memory such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory can optionally include one or more storage devices located remotely from the processor. The memory or, alternatively, the non-volatile memory device within the memory includes a non-transitory computer-readable storage medium. The features described in the present disclosure may be stored on any one of the machine-readable media, integrated with software and / or firmware that can control the hardware of the processing system and cause the processing system to interact with other mechanisms to utilize the results according to the embodiments of the present disclosure. Such software or firmware can include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

Industrial Applicability

[0356] Although the method proposed in the present disclosure has been mainly described with an example applied to an IEEE 802.11-based system, it can be applied to various wireless LANs or wireless communication systems other than the IEEE 802.11-based system.

Claims

1. A method performed by a first station (STA) multi-link device (MLD) in a wireless LAN system, the method comprising: transmitting to a second STA MLD a specific element including a multi-user (MU) EDCA (enhanced distributed channel access) mapping field, or receiving the specific element from the second STA MLD; performing a MU EDCA operation on at least one link based on the specific element, wherein the MU EDCA mapping field includes first information associated with the at least one link and second information associated with at least one traffic identifier (TID) corresponding to the at least one link.

2. The method according to claim 1, wherein the specific element is at least one of a TID-to-link element, an EDCA mapping element, or a LL (low latency) EDCA mapping element.

3. At least one of the TID-to-link element, the EDCA mapping element, or the LL EDCA mapping element includes an EDCA control field or a LL EDCA control field, wherein the MU EDCA control field or the LL EDCA control field includes a first sub-field indicating whether the MU EDCA mapping field exists in at least one of the TID-to-link element, the EDCA mapping element, or the LL EDCA mapping element. The method according to claim 2.

4. The MU EDCA mapping field includes a second sub-field including an ID value of the at least one link or a bitmap indicating the at least one link, wherein the first information is indicated by the second sub-field. The method according to claim 1.

5. The MU EDCA mapping field includes at least one third sub-field indicating at least one TID associated with the MU EDCA operation corresponding to each of the at least one link, wherein the second information is indicated by the at least one third sub-field. The method according to claim 4.

6. The method according to claim 5, wherein the number of the at least one third subfield is the same as the number of the at least one link.

7. The method according to claim 2, wherein the TID pair link element is configured based on a MU EDCAt parameter set element or an LL MU EDCAt parameter set element.

8. Based on the fact that the TID pair link element is configured based on the LL MU EDCAt parameter set element, the MU EDCAt mapping field is associated with an LL MU EDCAt operation, the at least one link for performing the LL MU EDCAt operation is indicated by the first information, the at least one TID associated with the LL MU EDCAt operation is indicated by the second information, the method according to claim 7.

9. The LL MU EDCAt parameter set element includes a plurality of LL MU TID parameter record fields, each of the plurality of LL MU TID parameter record fields includes an LL MU EDCAt timer subfield, the method according to claim 7.

10. The method according to claim 1, wherein the MU EDCAt mapping field includes third information associated with at least one AC (access category) associated with the MU EDCAt operation.

11. The MU EDCAt mapping field includes at least one fourth subfield indicating the at least one AC corresponding to each of the at least one link, the third information is indicated by the fourth subfield, the method according to claim 10.

12. The method according to claim 1, wherein the first STA MLD is a non-access point (AP) STA MLD, and the second STA MLD is an AP MLD.

13. A first station (STA) multi-link device (MLD) operating in a wireless LAN system, wherein the first STA MLD includes one or more transceivers, and one or more processors coupled to the one or more transceivers, the one or more processors include Transmit a specific element containing a multi-user (MU) EDCA (enhanced distributed channel access) mapping field to the second STA MLD, or receive the specific element from the second STA MLD via the one or more transceivers, configured to perform MU EDCA operations on at least one link based on the specific element, The first STA MLD, wherein the MU EDCA mapping field includes first information associated with the at least one link and second information associated with at least one traffic identifier (TID) corresponding to the at least one link.

14. A method performed by a second station (STA) MLD (multi-link device) in a wireless LAN system, the method comprising: generating a specific element containing a multi-user (MU) EDCA (enhanced distributed channel access) mapping field; transmitting the specific element containing the MU EDCA mapping field to a first STA MLD; The method, wherein the MU EDCA mapping field includes first information associated with the at least one link and second information associated with at least one traffic identifier (TID) corresponding to the at least one link.

15. A second station (STA) MLD (multi-link device) operating in a wireless LAN system, the second STA MLD comprising: one or more transceivers; one or more processors coupled to the one or more transceivers; The one or more processors are: configured to generate a specific element containing a multi-user (MU) EDCA (enhanced distributed channel access) mapping field; configured to transmit the specific element containing the MU EDCA mapping field to a first STA MLD via the one or more transceivers. The MU EDCA mapping field includes first information associated with the at least one link and second information associated with at least one traffic identifier (TID) corresponding to the at least one link, and is a second STA MLD.

16. A processing device configured to control a first station (STA) MLD (multi-link device) operating in a wireless LAN system, the processing device comprising: One or more processors; One or more computer memories operably coupled to the one or more processors and storing instructions for performing operations based on execution by the one or more processors; The operations include: Transmitting a specific element including a multi-user (MU) EDCA (enhanced distributed channel access) mapping field to a second STA MLD or receiving the specific element from the second STA MLD; Performing a MU EDCA operation on at least one link based on the specific element; The MU EDCA mapping field includes first information associated with the at least one link and second information associated with at least one traffic identifier (TID) corresponding to the at least one link, and is a processing device.

17. One or more non-transitory computer-readable media storing one or more instructions, The one or more instructions are executed by one or more processors, and a device operating in a wireless LAN system Transmits a specific element including a multi-user (MU) EDCA (enhanced distributed channel access) mapping field to a second STA MLD or receives the specific element from the second STA MLD, And is controlled to perform a MU EDCA operation on at least one link based on the specific element. The MU EDCA mapping field is a computer-readable medium including first information associated with the at least one link and second information associated with at least one traffic identifier (TID) corresponding to the at least one link.

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