MÉTODO E APARELHO PARA ROAMING BASEADO EM DISPOSITIVOS MÚLTIPLOS ENLACES EM SISTEMA DE LAN SEM FIO

Abstract

A method and apparatus for multi-link device (MLD)-based roaming in a wireless LAN system are disclosed. The method performed by a first STA in a wireless LAN system comprises the steps of: receiving, from a first access point (AP) belonging to a first group, announcement information including first information related to whether or not an addition of at least one link is supported for the first STA; transmitting, to the first AP, a request frame including a link ID of a second AP belonging to a second group; and receiving, from the first AP, a response frame including the link ID of the second AP, wherein the request frame may include second information requesting an addition or deletion of a link between the first STA and the second AP.

Description

1 / 79 “METHOD AND APPARATUS FOR ROAMING BASED ON MULTIPLE LINK DEVICES IN A WIRELESS LAN SYSTEM” TECHNICAL FIELD

[001] This disclosure relates to a roaming method and device based on a multi-link device (MLD) in a wireless local area network (WLAN) system. TECHNICAL BACKGROUND

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

[003] In order to provide a more advanced wireless communication environment, enhanced technologies for Extremely High Throughput (EHT) are being discussed. For example, technologies for MIMO and coordination of multiple access points (APs) that support higher bandwidth, efficient use of multiple bands, and wider spatial streams are being studied, and in particular, various technologies are being studied to support low latency or real-time traffic. In addition, new technologies are being discussed to support ultra-high reliability (UHR), including improvements or extensions of EHT technologies. Disclosure Technical Problem

[004] The technical problem of the present disclosure is to provide a method and device for roaming based on a multi-link device (MLD) in Petition 870250093439, dated 10 / 13 / 2025, page 7 / 100 2 / 79 a wireless LAN system.

[005] An additional technical problem of the present disclosure is to provide a method and device for supporting or performing station-only roaming (STA) between different access points (APs) affiliated to a common MLD in a wireless LAN system.

[006] An additional technical problem of the present disclosure is to provide a method and device for performing communication by adding / removing temporary links during an MLD-based roaming procedure in a wireless LAN system.

[007] The technical objectives to be achieved by the present disclosure are not limited to the technical objectives described above, and other technical objectives not described in the present invention will be clearly understood by those skilled in the relevant art from the following description. Technical Solution

[008] A method performed by a first station (STA) in a wireless LAN system according to an aspect of this disclosure may include receiving, from a first access point (AP) affiliated with a first group, advertisement information including first information relating to whether the addition of at least one link is supported for the first STA; transmitting, to the first AP, a request frame including a link ID of a second AP affiliated with a second group; and receiving, from the first AP, a response frame including the link ID of the second AP, and the request frame may include second information requesting the addition or deletion of a link between the first STA and the second AP.

[009] A method performed by a first access point (AP) included in a first group in a wireless LAN system according to another aspect of this disclosure may include transmitting, to a first Petition 870250093439, dated 10 / 13 / 2025, page 8 / 100 3 / 79 Station Access (STA), announcement information including first information regarding whether the addition of at least one link is supported for the first STA; receive, from the first STA, a request frame including a link ID of a second AP affiliated with a second group; and transmit, to the first STA, a response frame including the link ID of the second AP, and the request frame may include second information requesting the addition or deletion of a link between the first STA and the second AP. Technical Effects

[010] According to the present disclosure, a method and device for roaming based on a multi-link device (MLD) in a wireless LAN system can be provided.

[011] According to the present disclosure, a method and device for supporting or performing station roaming (STA) between different access points (APs) affiliated to a common MLD in a wireless LAN system can be provided.

[012] According to the present disclosure, a further technical problem of the present disclosure is a method and device for performing communication by adding / removing a temporary link while performing an MLD-based roaming procedure in a wireless LAN system.

[013] The effects attainable by the present disclosure are not limited to the effects described above, and other effects not described in the present invention can be clearly understood by those skilled in the relevant art from the following description. Description of the Diagrams

[014] The accompanying drawings, included as part of the detailed description for understanding this disclosure, provide embodiments of this disclosure and describe technical features of this disclosure with description Petition 870250093439, dated 10 / 13 / 2025, p. 9 / 100 4 / 79 detailed.

[015] Figure 1 illustrates a block configuration diagram of a wireless communication device according to an embodiment of the present disclosure.

[016] Figure 2 is a diagram that illustrates an exemplary structure of a WLAN system to which the present disclosure can be applied.

[017] Figure 3 is a diagram to describe a link setup process to which this disclosure can be applied.

[018] Figure 4 is a diagram to describe a pullback process to which the present disclosure can be applied.

[019] Figure 5 is a diagram to describe a CSMA / CA-based frame transmission operation to which this disclosure may be applied.

[020] Figure 6 is a diagram to describe an example of a frame structure used in a WLAN system to which the present disclosure may be applied.

[021] Figure 7 is a diagram that illustrates examples of PPDUs defined in the IEEE 802.11 standard to which this disclosure can be applied.

[022] Figure 8 illustrates an exemplary structure of an ML element to which the present disclosure can be applied.

[023] Figure 9 is a diagram that illustrates an example of a high-level structure for an AP MLD to which the present disclosure can be applied.

[024] Figure 10 is a diagram illustrating BSS transition in a conventional wireless LAN system.

[025] Figure 11 is a diagram illustrating an example of a method for performing MLD-based roaming by an STA in accordance with this disclosure.

[026] Figure 12 is a diagram that illustrates an example of a method for Petition 870250093439, dated 10 / 13 / 2025, page 10 / 100 5 / 79 an AP to support MLD-based roaming via a STA in accordance with this disclosure.

[027] Figure 13 is a diagram that illustrates an example of the structure and procedure of MLD-based roaming according to this disclosure.

[028] Figure 14 is a diagram that illustrates an example of an element including advertising information in accordance with this disclosure.

[029] Figure 15, Figure 16, and Figure 17 are diagrams that illustrate an example of a reconfiguration ML element according to the present disclosure.

[030] Figure 18 is a diagram that illustrates an example of the structure and procedure of MLD-based roaming according to this disclosure. Best Way

[031] The embodiments in accordance with this disclosure will be described in detail hereafter with reference to the accompanying drawings. The detailed description to be disclosed with the accompanying drawings is intended to describe exemplary embodiments of the present disclosure and does not represent the only embodiment in which the present disclosure may be implemented. The detailed description below includes specific details to provide a complete understanding of this disclosure. However, those skilled in the relevant art know that the present disclosure may be implemented without such specific details.

[032] In some cases, known structures and devices may be omitted or may be shown in the form of a block diagram based on a central function of each structure and device, in order to avoid ambiguity with a concept in the present disclosure.

[033] In this disclosure, when an element is referred to as “connected,” “combined,” or “linked” to another element, it may include an indirect connection relationship that another element presents between them, as well as a direct connection relationship. Furthermore, in this disclosure, the term “include” Petition 870250093439, dated 10 / 13 / 2025, page 11 / 100 6 / 79 or “have” specifies the presence of a mentioned resource, step, operation, component and / or element, but does not exclude the presence or addition of one or more other resources, steps, operations, components, elements and / or their groups.

[034] In the present disclosure, a term such as “first”, “second”, etc. is used only to distinguish one element from another and is not used to limit elements and, unless otherwise specified, does not limit an order or importance, etc., among the elements. Consequently, within the scope of the present disclosure, a first element in one embodiment may be referred to as a second element in another embodiment and, similarly, a second element in one embodiment may be referred to as a first element in another embodiment.

[035] A term used in this disclosure is intended to describe a specific embodiment and not to limit a claim. As used in a described and attached claim of an embodiment, the singular form is intended to include a plural form unless the context clearly indicates otherwise. A term used in this disclosure, “and / or”, may refer to one of the related enumerated items or may mean that it refers to and includes any and all possible combinations of two or more of them. In addition, “ / ” between words in this disclosure has the same meaning as “and / or”, unless otherwise indicated.

[036] Examples of this disclosure can be applied to various wireless communication systems. For example, examples of this disclosure can be applied to a wireless LAN system. For example, examples of this disclosure can be applied to a wireless LAN based on the IEEE 802.11a / g / n / ac / ax standards. In addition, examples of this disclosure can be applied to a wireless LAN based on the newly proposed IEEE 802.11be (or EHT) standard. Examples of this disclosure can be applied to a wireless LAN. Petition 870250093439, dated 10 / 13 / 2025, p. 12 / 100 7 / 79 based on the IEEE 802.11be Version 2 standard, corresponding to a further enhancement technology of the IEEE 802.11be Version 1 standard. Additionally, examples of this disclosure can be applied to a wireless LAN based on next-generation standards, subsequent to IEEE 802.11be. Furthermore, examples of this disclosure can be applied to a cellular wireless communication system. For example, it can be applied to a cellular wireless communication system based on Long Term Evolution (LTE) technology and the 5G New Radio (NR) technology of the 3rd Generation Partnership Project (3GPP) Standard.

[037] The technical resources to which the examples in this disclosure can be applied will be described below.

[038] Figure 1 illustrates a block diagram of a wireless communication device according to an embodiment of the present disclosure.

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

[040] Devices 100 and 200 illustrated in Figure 1 can be referred to as stations (STAs). For example, devices 100 and 200 illustrated in Figure 1 can be referred to by various terms, such as transmitting device, receiving device, transmitting STA, and receiving STA. For example, STAs 110 and Petition 870250093439, dated 10 / 13 / 2025, page 13 / 100 8 / 79 200 can perform an access point (AP) function or a non-AP function. That is, in this disclosure, STAs 110 and 200 can perform AP and / or non-AP functions. When STAs 110 and 200 perform an AP function, they can simply be referred to as APs, and when STAs 110 and 200 perform non-AP functions, they can simply be referred to as STAs. Furthermore, in this disclosure, an AP can also be referred to as an AP STA.

[041] Referring to Figure 1, the first device 100 and the second device 200 can transmit and receive radio signals using various wireless LAN technologies (e.g., IEEE 802.11 series). The first device 100 and the second device 200 can include an interface to a medium access control (MAC) layer and a physical layer (PHY) compliant with the IEEE 802.11 standard.

[042] In addition, the first device 100 and the second device 200 can additionally support various communication standards (e.g., LTE 3GPP series, NR 5G series, etc.) in addition to wireless LAN technology. Furthermore, the device of this disclosure can be implemented in various devices such as mobile phones, vehicles, personal computers, augmented reality (AR) equipment and virtual reality (VR) equipment, etc. In addition, the STA of this specification can support various communication services such as voice calls, video calls, data communication, autonomous driving, machine-to-machine communication (MTC), machine-to-machine communication (M2M), device-to-device communication (D2D), IoT (Internet of Things), etc.

[043] A first device 100 may include one or more processors 102 and one or more memories 104 and may additionally include one or more transceivers 106 and / or one or more antennas 108. A processor 102 may control a memory 104 and / or a transceiver 106 and may be configured to implement Petition 870250093439, dated 10 / 13 / 2025, p. 14 / 100 9 / 79 descriptions, functions, procedures, proposals, methods and / or flowcharts of operation disclosed in this disclosure. For example, a processor 102 can transmit a wireless signal, including the first information / signal, through a transceiver 106, after generating the first information / signal by processing information in a memory 104. Furthermore, a processor 102 can receive a wireless signal, including the second information / signal, through a transceiver 106 and then store the information obtained by processing the second information / signal in a memory 104. A memory 104 can be connected to a processor 102 and can store a variety of information related to the operation of a processor 102.For example, a memory 104 may store software code, including instructions to perform all or part of the processes controlled by a processor 102 or to perform descriptions, functions, procedures, proposals, methods and / or flowcharts of operation disclosed in this disclosure. In the present invention, a processor 102 and a memory 104 may be part of a communication modem / circuit / chip designed to implement a wireless LAN technology (e.g., IEEE 802.11 series). A transceiver 106 may be connected to a processor 102 and may transmit and / or receive a wireless signal by means of one or more antennas 108. A transceiver 106 may include a transmitter and / or a receiver. A transceiver 106 may be used in conjunction with an RF (Radio Frequency) unit. In this disclosure, a device may mean a communication modem / circuit / chip.

[044] A second device 200 may include one or more processors 202 and one or more memories 204 and may additionally include one or more transceivers 206 and / or one or more antennas 208. A processor 202 may control a memory 204 and / or a transceiver 206 and may be configured to implement descriptions, functions, procedures, proposals, methods and / or operating flowcharts disclosed in this disclosure. For example, a processor 202 may generate Petition 870250093439, dated 10 / 13 / 2025, p. 15 / 100 10 / 79 a third piece of information / signal processing information in a memory 204 and then transmitting a wireless signal including the third piece of information / signal via a transceiver 206. Additionally, a processor 202 can receive a wireless signal including a fourth piece of information / signal via a transceiver 206 and then store the information obtained by processing the fourth piece of information / signal in a memory 204. A memory 204 can be connected to a processor 202 and can store a variety of information related to an operation of a processor 202. For example, a memory 204 can store software code including instructions for performing all or part of the processes controlled by a processor 202 or for performing descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this disclosure.In the present invention, a processor 202 and a memory 204 can be part of a communication modem / circuit / chip designed to implement a wireless LAN technology (e.g., IEEE 802.11 series). A transceiver 206 can be connected to a processor 202 and can transmit and / or receive a wireless signal via one or more antennas 208. A transceiver 206 can include a transmitter and / or a receiver. A transceiver 206 can be used in conjunction with an RF unit. In the present disclosure, a device can mean a communication modem / circuit / chip.

[045] Next, a hardware element of a device 100, 200 will be described in more detail. Not limited to this, but one or more protocol layers may be implemented by one or more processors 102, 202. For example, one or more processors 102, 202 may implement one or more layers (e.g., a functional layer such as PHY, MAC). One or more processors 102, 202 may generate one or more PDUs (Protocol Data Units) and / or one or more SDUs (Service Data Units) according to the description, functions, procedures, proposals, methods and / or flowcharts of Petition 870250093439, dated 10 / 13 / 2025, p. 16 / 100 11 / 79 operation disclosed in this disclosure. One or more processors 102, 202 may generate a message, control information, data, or information in accordance with the description, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this disclosure. One or more processors 102, 202 may generate a signal (e.g., a baseband signal) including a PDU, an SDU, a message, control information, data, or information in accordance with the functions, procedures, proposals, and / or methods disclosed in this disclosure to provide it to one or more transceivers 106, 206. One or more processors 102, 202 may receive a signal (e.g., a baseband signal) from one or more transceivers 106, 206 and obtain a PDU, an SDU, a message, control information, data, or information in accordance with the description, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this disclosure.

[046] One or more 102, 202 processors may be referred to as a controller, microcontroller, microprocessor, or microcomputer. One or more 102, 202 processors may be implemented by hardware, firmware, software, or a combination of both. In one example, one or more ASICs (Application-Specific Integrated Circuits), one or more DSPs (Digital Signal Processors), one or more DSPDs (Digital Signal Processing Devices), one or more PLDs (Programmable Logic Devices), or one or more FPGAs (Field-Programmable Gate Arrays) may be included in one or more 102, 202 processors. Descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this disclosure may be implemented using firmware or software, and firmware or software may be implemented to include a module, a procedure, a function, etc.Firmware or software configured to perform the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this disclosure may be... Petition 870250093439, dated 10 / 13 / 2025, page 17 / 100 12 / 79 included in one or more 102, 202 processors or may be stored in one or more 104, 204 memories and controlled by one or more 102, 202 processors. Description, functions, procedures, proposals, methods and / or flowcharts of operation disclosed in this disclosure may be implemented using firmware or software in the form of code, an instruction and / or a set of instructions.

[047] One or more 104, 204 memories may be connected to one or more 102, 202 processors and may store data, a signal, a message, information, a program, a code, an indication and / or an instruction in various forms. One or more 104, 204 memories may be configured with ROM, RAM, EPROM, a flash memory, a hard disk, a cash register, a box memory, a computer-readable storage medium and / or a combination thereof. One or more 104, 204 memories may be positioned inside and / or outside one or more 102, 202 processors. Furthermore, one or more 104, 204 memories may be connected to one or more 102, 202 processors by means of a variety of technologies, such as wired or wireless connection.

[048] One or more transceivers 106, 206 may transmit user data, control information, a wireless signal / channel, etc., mentioned in the methods and / or flowcharts of operation, etc., of this disclosure, to one or more other devices. One or more transceivers 106, 206 may receive user data, control information, a wireless signal / channel, etc., mentioned in the description, functions, procedures, proposals, methods and / or flowcharts of operation, etc., disclosed in this 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 may transmit and receive a wireless signal. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to transmit user data, control information, or a wireless signal. Petition 870250093439, dated 10 / 13 / 2025, page 18 / 100 13 / 79 for one or more other devices. Furthermore, one or more processors 102, 202 can control one or more transceivers 106, 206 to receive user data, control information, or a wireless signal from one or more other devices. Additionally, one or more transceivers 106, 206 can be connected to one or more antennas 108, 208, and one or more transceivers 106, 206 can be configured to transmit and receive user data, control information, a wireless signal / channel, etc., mentioned in the description, functions, procedures, proposals, methods, and / or operating flowcharts, etc., disclosed in this disclosure, through one or more antennas 108, 208. In this disclosure, one or more antennas can be a plurality of physical antennas or a plurality of logical antennas (e.g., an antenna port). One or more 106, 206 transceivers can convert a received wireless signal / channel, etc.One or more 102, 202 processors can convert user data, control information, a wireless signal / channel, etc., from a baseband signal to an RF signal, using one or more 102, 202 processors. One or more 106, 206 transceivers can convert user data, control information, a wireless signal / channel, etc., which are processed using one or more 102, 202 processors, from a baseband signal to an RF signal. Therefore, one or more 106, 206 transceivers may include an (analog) oscillator and / or a filter.

[049] For example, one of the STAs 100 and 200 may perform an intended AP operation, and the other of the STAs 100 and 200 may perform an intended non-AP STA operation. For example, transceivers 106 and 206 in Figure 1 may perform a transmit and receive operation of a signal (e.g., a packet or a physical layer protocol data unit (PPDU) compliant with IEEE 802.11a / b / g / n / ac / ax / be). Furthermore, in this disclosure, an operation in which multiple STAs generate transmit / receive signals or perform advance data processing or calculation for transmit / receive signals may be performed by Petition 870250093439, dated 10 / 13 / 2025, page 19 / 100 14 / 79 processors 102 and 202 of Figure 1. For example, an example of an operation to generate a transmit / receive signal or perform data processing or calculation in advance for the transmit / receive signal may include 1) determining / acquiring / configuring / calculating / decoding / encoding bit information of fields (signal (SIG), short training field (STF), long training field (LTF), data, etc.) included in the PPDU, 2) determining / configuring / acquiring timing resources or frequency resources (e.g., subcarrier resources) used for fields (SIG, STF, LTF, data, etc.) included in the PPDU; 3) determining / configuring / acquiring a specific sequence (e.g., pilot sequence, STF / LTF sequence, extra sequence applied to SIG) used for fields (SIG, STF, LTF, data, etc.).) included in the PPDU action; 4) power control operation and / or power saving operation applied to the STA; 5) operations related to the determination / acquisition / configuration / calculation / decoding / encoding of the ACK signal, etc. Furthermore, in the following example, various information (e.g., information related to fields / subfields / control fields / parameters / power, etc.) used by various STAs to determine / acquire / configure / calculate / decode / encode transmission and reception signals can be stored in memories 104 and 204 of Figure 1.

[050] Hereafter, downlink (DL) may mean a link for communication from an AP STA to a non-AP STA, and a DL PPDU / packet / signal may be transmitted and received via the DL. In DL communication, a transmitter may be part of an AP STA and a receiver may be part of a non-AP STA. Uplink (UL) may mean a link for communication from non-AP STAs to AP STAs, and a UL PPDU / packet / signal may be transmitted and received via the UL. In UL communication, a transmitter may be part of a non-AP STA and a receiver may be part of an AP STA. Petition 870250093439, dated 10 / 13 / 2025, p. 20 / 100 15 / 79

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

[052] The structure of a wireless LAN system can consist of a plurality of components. A wireless LAN that supports STA mobility transparent to a higher layer can be provided by the interaction of a plurality of components. A Basic Service Set (BSS) corresponds to a basic building block of a wireless LAN. Figure 2 shows, exemplarily, that there are two BSSs (BSS1 and BSS2) and two STAs are included as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). An ellipse representing a BSS in Figure 2 can also be understood as representing a coverage area in which the STAs included in the corresponding BSS maintain communication. This area can be called a Basic Service Area (BSA). When an STA leaves the BSA, it may not communicate directly with other STAs within the BSA.

[053] If the DS shown in Figure 2 is not considered, the most basic type of BSS in a wireless LAN is an independent BSS (IBSS). For example, the IBSS can have a minimal form containing only two STAs. For example, assuming other components are omitted, BSS1 containing only STA1 and STA2 or BSS2 containing only STA3 and STA4 can, respectively, correspond to representative examples of IBSS. This configuration is possible when the STAs can communicate directly without an AP. Furthermore, in this type of wireless LAN, it is not configured in advance, but can be configured when a LAN is needed, and this can be termed an ad hoc network. Since the IBSS does not include an AP, there is no centralized management entity. That is, in the IBSS, the STAs are managed in a distributed manner. In the IBSS, all STAs can be composed of mobile STAs, and access to the distributed system (DS) is not allowed, forming a self-contained network. Petition 870250093439, dated 10 / 13 / 2025, page 21 / 100 16 / 79

[054] A STA’s association with the BSS can be dynamically changed by turning the STA on or off, entering or leaving the BSS area, and similar actions. To become a member of the BSS, the STA can join the BSS using a synchronization process. To access all services of the BSS infrastructure, the STA must be associated with the BSS. This association can be established dynamically and may include the use of a Distributed System Service (DSS).

[055] A direct distance from STA to STA in a wireless LAN may be limited by PHY performance. In some cases, this distance limit may be sufficient, but in others, communication between STAs at a greater distance may be necessary. A distributed system (DS) can be configured to support extended coverage.

[056] DS stands for a structure in which BSSs are interconnected. Specifically, as shown in Figure 2, a BSS can exist as an extended form of a network composed of a plurality of BSSs. DS is a logical concept and can be specified by the Distributed System Media (DSM) characteristics. In this sense, a wireless medium (WM) and a DSM can be logically separated. Each logical medium is used for a different purpose and by different components. These media are not limited to being the same, nor to being different. Thus, the flexibility of the wireless LAN structure (DS structure or other network structure) can be explained by the fact that a plurality of media is logically different. That is, the wireless LAN structure can be implemented in various ways, and the corresponding wireless LAN structure can be specified independently by the physical characteristics of each mode.

[057] A DS can support a mobile device, providing seamless integration of a plurality of BSSs and providing the logical services needed to address an address to a destination. In addition, the DS can also include a component called a portal that serves as a bridge to Petition 870250093439, dated 10 / 13 / 2025, page 22 / 100 17 / 79 connection between the wireless LAN and other networks (e.g., IEEE 802.X).

[058] The AP allows access to the DS through the WM for the associated non-AP STAs and represents an entity that also has the functionality of an STA. Data movement between the BSS and the DS can be performed through the AP. For example, STA2 and STA3 shown in Figure 2 have the functionality of STAs and provide a function that allows the associated non-AP STAs (STA1 and STA4) to access the DS. Furthermore, since all APs basically correspond to STAs, all APs are addressable entities. The address used by the AP for communication in the WM and the address used by the AP for communication in the DSM are not necessarily the same. A BSS composed of an AP and one or more STAs can be called an infrastructure BSS.

[059] Data transmitted from one of the STAs associated with an AP to a corresponding AP STA address can always be received on an uncontrolled port and can be processed by an IEEE 802.1X port access entity. Furthermore, when a controlled port is authenticated, the transmission data (or frames) can be delivered to the DS.

[060] In addition to the DS structure described above, an extended services suite (ESS) can be configured to provide broad coverage.

[061] An ESS stands for a network in which a network of arbitrary size and complexity is composed of DSs and BSSs. The ESS may correspond to a set of BSSs connected to a DS. However, the ESS does not include the DS. An ESS network is characterized by being viewed as an IBSS at the Logical Link Control (LLC) layer. The STAs included in the ESS can communicate with each other, and mobile STAs can move from one BSS to another BSS (within the same ESS) transparently to the LLC. The APs included in an ESS may have the same Service Set Identification (SSID). The SSID is differentiated from the BSSID, which is a BSS identifier. Petition 870250093439, dated 10 / 13 / 2025, page 23 / 100 18 / 79

[062] The wireless LAN system assumes nothing about the relative physical locations of the BSSs, and all of the following forms are possible. BSSs may partially overlap, which is a commonly used form to provide continuous coverage. Additionally, BSSs may not be physically connected, and logically, there is no limit to the distance between them. Furthermore, BSSs may be physically located in the same location, which can be used to provide redundancy. Additionally, one (or more) IBSS or ESS network may physically exist in the same space as one (or more) ESS network. When an ad hoc network operates in a location where an ESS network exists, when physically overlapping wireless networks are configured by different organizations, or when two or more different access and security policies are required in the same location, this may correspond to the form of a similar ESS network.

[063] Figure 3 is a diagram to explain a link configuration process to which the present disclosure can be applied.

[064] In order for an STA to establish a link with respect to a network and transmit / receive data, it first discovers a network, performs authentication, establishes an association, and needs to perform the authentication process for security. The link configuration process may also be referred to as the session initiation process or session setup process. In addition, the discovery, authentication, association, and security configuration processes of the link configuration process may be collectively referred to as the association process.

[065] In step S310, the STA can perform a network discovery operation. The network discovery operation may include a scanning operation by the STA. That is, for the STA to access the network, it needs to find a network in which it can participate. The STA must identify a compatible network before participating in a wireless network, and the process of identifying an existing network in a Petition 870250093439, dated 10 / 13 / 2025, page 24 / 100 19 / 79 specific area is called a scan.

[066] Scanning schemes include active scanning and passive scanning. Figure 3 illustrates, in an exemplary way, a network discovery operation including an active scanning process. In active scanning, a STA performing the scan transmits a probe request frame to discover which APs exist around it while moving through channels and waiting for a response. A responder transmits a probe response frame in response to the probe request frame to the STA that transmitted the probe request frame. In the present invention, the responder can be an STA that last transmitted a beacon frame on the BSS of the channel being scanned. On the BSS, as the AP transmits the beacon frame, it becomes a responder, and on the IBSS, the STAs on the IBSS rotate to transmit the beacon frame, so the responder is not constant.For example, a STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 can store BSS-related information included in the received probe response frame and can move on to the next channel (e.g., channel 2) and perform the scan (i.e., transmit / receive a probe request / response on channel 2) in the same manner.

[067] Although not shown in Figure 3, the scanning operation can be performed passively. In passive scanning, a STA performing the scan waits for a beacon frame while moving through channels. The beacon frame is one of the management frames defined in IEEE 802.11 and is transmitted periodically to notify of the existence of a wireless network and allow the STA performing the scan to find a wireless network and join the wireless network. In BSS, the AP serves to transmit beacon frames periodically, and in IBSS, the STAs within the IBSS rotate to transmit beacon frames. When the STA performing the scan receives a beacon frame, the STA stores information. Petition 870250093439, dated 10 / 13 / 2025, p. 25 / 100 20 / 79 for the BSS included in the beacon frame and records the beacon frame information on each channel while moving to another channel. The STA that receives the beacon frame can store information related to the BSS included in the received beacon frame, move to the next channel, and perform the scan on the next channel in the same way. Comparing active scanning with passive scanning, active scanning has the advantage of exhibiting less delay and lower power consumption than passive scanning.

[068] After the STA discovers the network, an authentication process can be performed in step S320. This authentication process can be referred to as a first authentication process, so as to be clearly differentiated from the security configuration operation of step S340, to be described later.

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

[070] The authentication frame includes an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a robust security network (RSN), and a Finite Cyclic Group, etc. These are some examples of information that can be included in the authentication request / response frame and can be replaced by other information or additional information can be included.

[071] The STA can transmit an authentication request frame to the AP. The AP can determine whether or not to allow authentication of the corresponding 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 via an authentication response frame. Petition 870250093439, dated 10 / 13 / 2025, p. 26 / 100 21 / 79

[072] After the STA is successfully authenticated, a binding process can be executed in step S330. The binding process includes a process in which the STA transmits a binding request frame to the AP and, in response, the AP transmits a binding response frame to the STA.

[073] For example, the association request frame may include information related to various capabilities, a beacon listening interval, a service set identifier (SSID), supported rates, supported channels, RSN, mobility domain, supported operating classes, traffic indication map broadcast request (TIM broadcast request), interoperability service capability, etc. For example, the association response frame may include information related to various capabilities, status code, association ID (AID), supported rates, channel enhanced distributed access parameter set (EDCA), received channel power indicator (RCPI), received signal-to-noise indicator (RSNI), mobility domain, timeout interval (e.g., association return time), overlapping BSS scan parameters, TIM broadcast response, Quality of Service (QoS) map, etc.This corresponds to some examples of information that can be included in the association request / response form and can be replaced by other information, or additional information can be included.

[074] After the STA is successfully associated with the network, a security configuration process can be performed in step S340. The security configuration process in step S340 can be referred to as a Robust Security Network Association (RSNA) request / response authentication process, and the authentication process in step S320 is referred to as a first authentication process, and the security configuration process in step S340 can also be referred to Petition 870250093439, dated 10 / 13 / 2025, page 27 / 100 22 / 79 simply as an authentication process.

[075] The security configuration process of the S340 step may include, for example, a process of configuring a private key via a four-way handshake using an Extensible Authentication Protocol over LAN (EAPOL) frame. Additionally, the security configuration process may be performed according to a security scheme not defined in the IEEE 802.11 standard.

[076] Figure 4 is a diagram to explain a pullback process to which the present disclosure can be applied.

[077] In wireless LAN systems, a basic access mechanism for media access control (MAC) is a carrier-sensing collision avoidance multiple access mechanism (CSMA / CA). The CSMA / CA mechanism is also the IEEE 802.11 MAC Distributed Coordination Function (DCF) and basically adopts a "listen before you speak" access mechanism. According to this type of access mechanism, the AP and / or STA can perform a Free Channel Assessment (CCA) by detecting a radio channel or medium during a predetermined time interval (e.g., DCF Inter-Frame Space (DIFS)), before initiating transmission. As a result of the detection, if it is determined that the medium is in an idle state, frame transmission is initiated through the corresponding medium.On the other hand, if it is detected that the medium is busy, the AP and / or the corresponding STA does not initiate its own transmission and can set a delay period for accessing the medium (e.g., a random wait period) and attempt to transmit frames after the wait. By applying the random wait period, since multiple STAs are expected to attempt to transmit frames after waiting for different periods of time, collisions can be minimized.

[078] In addition, the IEEE 802.11 MAC protocol provides a Hybrid Coordination Function (HCF). The HCF is based on the DCF and the Coordination Function Petition 870250093439, dated 10 / 13 / 2025, page 28 / 100 Point Frame 23 / 79 (PCF). PCF is a synchronous access method based on polling and refers to a method in which all receiving APs and / or STAs periodically poll to receive data frames. In addition, HCF has Enhanced Distributed Channel Access (EDCA) and HCF Controlled Channel Access (HCCA). EDCA is a contention-based access method for a provider to deliver data frames to multiple users, and HCCA uses a non-contentation-based channel access method using a polling mechanism. Furthermore, HCF includes a medium access mechanism to improve the QoS (Quality of Service) of the wireless LAN and can transmit QoS data in both a Contention Period (CP) and a Contention-Free Period (CFP).

[079] Referring to Figure 4, an operation based on a random backoff period will be described. When the busy / busy medium changes to an idle state, several STAs can attempt to transmit data (or frames). As a method to minimize collisions, each of the STAs can, respectively, select a random backoff count and attempt transmission after waiting a corresponding time slot. The random backoff count has a pseudorandom integer value and can be determined as one of values ​​ranging from 0 to CW. In the present invention, CW is a contention window parameter value. The CW parameter receives CWmin as its initial value, but can assume a value twice as large in case of transmission failure (for example, when an ACK for the transmitted frame is not received).When the CW parameter value reaches CWmax, data transmission can be attempted by maintaining the CWmax value until data transmission is successful, and when data transmission is successful, the CWmin value is reset. The CW, CWmin, and CWmax values ​​are preferably defined as 2n-1 (n = 0, 1, 2, ...).

[080] When the random recoil process is initiated, the STA continuously monitors the medium while performing the countdown of the slots. Petition 870250093439, dated 10 / 13 / 2025, page 29 / 100 24 / 79 countdown according to the determined countdown value. When the medium is monitored for occupancy, it interrupts the countdown and waits, resuming the remainder of the countdown when the medium becomes idle.

[081] In the example in Figure 4, when a packet to be transmitted arrives at the MAC of STA3, STA3 can transmit the frame immediately after confirming that the medium is idle for up to DIFS. The remaining STAs monitor and wait until the medium is busy. Meanwhile, the data to be transmitted can also occur in each of STA1, STA2, and STA5, and each STA waits for up to DIFS when the medium is monitored as idle, and then can perform a countdown of the backslot according to the random backslot count value selected by each STA. Suppose STA2 selects the lowest backslot count value and STA1 selects the highest backslot count value. That is, it exemplifies the case where the remaining backslot time of STA5 is less than the remaining backslot time of STA1 at the moment when STA2 completes the backslot count and starts transmitting the frame. STA1 and STA5 temporarily interrupt the countdown and wait while STA2 occupies the middle.When STA2's occupation ends and the medium becomes idle again, STA1 and STA5 wait for the DIFS and resume the interrupted rewind count. That is, frame transmission can be initiated after the countdown of the remaining rewind slots to the remaining rewind time. Since STA5's remaining rewind time is less than STA1's, STA5 starts frame transmission. While STA2 occupies the medium, data to be transmitted can also occur on STA4. From STA4's point of view, when the medium becomes idle, STA4 can wait for the DIFS and then perform a countdown according to the random rewind count value selected by STA4 and start frame transmission. The example in Figure 4 shows a case where STA5's remaining rewind time coincides with STA4's random rewind count value by chance. In this case, Petition 870250093439, dated 10 / 13 / 2025, page 30 / 100 On 25 / 79, a collision may occur between STA4 and STA5. When a collision occurs, neither STA4 nor STA5 receive an ACK, resulting in a data transmission failure. In this case, STA4 and STA5 may double the CW value, select a random backcount value, and perform a countdown. STA1 waits while the medium is busy due to the transmission from STA4 and STA5, waits for the DIFS when the medium becomes idle, and then starts transmitting frames after the remaining backtime has elapsed.

[082] As in the example in Figure 4, a data frame is a frame used for transmitting data forwarded to a higher layer and can be transmitted after a fallback performed after the completion of the DIFS, when the medium becomes idle. Additionally, a management frame is a frame used for exchanging management information that is not forwarded to a higher layer and is transmitted after a fallback performed after an IFS, such as DIFS or Point Coordination Function IFS (PIFS). Subtypes of management frames include Beacon, association request / response, reassociation request / response, polling request / response, authentication request / response, etc. A control frame is a frame used to control access to a medium.Control frame subtypes include Request to Send (RTS), Send Release (CTS), Acknowledgment (ACK), Power Saving Poll (PS-Poll), Block ACK (BlockAck), Block ACK Request (BlockACKReq), Null Data Packet Announcement (NDP Announcement), Trigger, etc. If the control frame is not a response frame from the previous frame, it will be transmitted after the backoff performed after the completion of the DIFS, and if it is a response frame from the previous frame, it will be transmitted without performing the backoff after the completion of the Short IFS (SIFS). The frame type and subtype can be identified by a type field and a subtype field in a frame control field (FC). Petition 870250093439, dated 10 / 13 / 2025, page 31 / 100 26 / 79

[083] A Quality of Service (QoS) STA can perform the fallback that is performed after an Arbitration IFS (AIFS) for an Access Category (AC) to which the frame belongs, i.e., AIFS[i] (where i is a value determined by AC), and then can transmit the frame. In the present invention, the frame in which AIFS[i] can be used can be a data frame, a management frame, or a control frame other than a response frame.

[084] Figure 5 is a diagram to explain a CSMA / CA-based frame transmission operation to which this disclosure can be applied.

[085] As described above, the CSMA / CA mechanism includes virtual carrier detection, in addition to physical carrier detection, in which an STA directly detects a medium. Virtual carrier detection aims to compensate for problems that may occur in accessing the medium, such as a hidden node problem. For virtual carrier detection, the STA's MAC address can use a Network Allocation Vector (NAV). The NAV is a value that indicates, to other STAs, the remaining time until the medium is available for use by an STA that currently uses it or has the right to use it. Therefore, the value set as NAV corresponds to a period in which the medium is scheduled to be used by the STA transmitting the frame, and the STA receiving the NAV value is prohibited from accessing the medium during the corresponding period. For example, the NAV can be configured based on the value of the "duration" field in the frame's MAC header.

[086] In the example in Figure 5, it is assumed that a STA1 intends to transmit data to a STA2, and a STA3 is in a position capable of intercepting some or all of the frames transmitted and received between STA1 and STA2.

[087] In order to reduce the possibility of collisions between multiple STA transmissions in a CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames can be applied. In the example in Figure 5, while the transmission of STA1 is being performed, as a result of Petition 870250093439, dated 10 / 13 / 2025, p. 32 / 100 27 / 79 carrier detection of STA3, it can be determined that the medium is in an idle state. That is, STA1 may correspond to a hidden node of STA3. Alternatively, in the example of Figure 5, it can be determined that the medium resulting from the carrier detection of STA3 is in an idle state while the transmission of STA2 is being performed. That is, STA2 may correspond to a hidden node of STA3. By exchanging RTS / CTS frames before performing data transmission and reception between STA1 and STA2, an STA outside the transmission range of either STA1 or STA2, or an STA outside the carrier detection range for transmission of STA1 or STA3, cannot attempt to occupy the channel during data transmission and reception between STA1 and STA2.

[088] Specifically, STA1 can determine if a channel is being used through carrier sensing. In terms of physical carrier sensing, STA1 can determine an idle channel occupancy state based on a power level or signal correlation detected on a channel. Additionally, in terms of virtual carrier sensing, STA1 can determine a channel occupancy state using a network allocation vector (NAV) timer.

[089] STA1 can transmit an RTS frame to STA2 after performing a pullback when the channel is idle during DIFS. When STA2 receives the RTS frame, STA2 can transmit a CTS frame in response to the RTS frame to STA1 after SIFS.

[090] If STA3 cannot intercept the CTS frame from STA2, but can intercept the RTS frame from STA1, STA3 may set a NAV timer for a period of frame transmission (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame) that will be transmitted continuously thereafter, using the duration information included in the RTS frame. Alternatively, if STA3 can intercept a CTS frame from STA2, but cannot intercept an RTS frame from STA1, STA3 may set a timer Petition 870250093439, dated 10 / 13 / 2025, p. 33 / 100 28 / 79 NAV is set for a frame transmission period (e.g., SIFS + data frame + SIFS + ACK frame) that will be transmitted continuously thereafter, using the duration information included in the CTS frame. That is, if STA3 can intercept one or more RTS or CTS frames from one or more STA1 or STA2 stations, STA3 can set the NAV accordingly. When STA3 receives a new frame before the NAV timer expires, STA3 can update the NAV timer using the duration information included in the new frame. STA3 does not attempt to access the channel until the NAV timer expires.

[091] When STA1 receives the CTS frame from STA2, STA1 can transmit the data frame to STA2 after SIFS once the CTS frame reception is complete. When STA2 successfully receives the data frame, STA2 can transmit an ACK frame in response to the data frame to STA1 after SIFS. STA3 can determine if the channel is being used via carrier detection when the NAV timer expires. When STA3 determines that the channel is not being used by other terminals during DIFS after the NAV timer expires, STA3 can attempt to access the channel after a contention window (CW) has passed according to a random backoff.

[092] Figure 6 is a diagram to explain an example of a frame structure used in a WLAN system to which the present disclosure can be applied.

[093] By means of an instruction or primitive (i.e., a set of instructions or parameters) from the MAC layer, the PHY layer can prepare a MAC PDU (MPDU) to be transmitted. For example, when a command requesting the start of transmission from the PHY layer is received from the MAC layer, the PHY layer switches to transmission mode and configures the information (e.g., data) provided by the MAC layer into a frame and transmits it. Furthermore, when the PHY layer detects a valid preamble in the received frame, the layer Petition 870250093439, dated 10 / 13 / 2025, page 34 / 100 29 / 79 PHY monitors the preamble header and sends a command notifying the MAC layer of the start of reception from the PHY layer.

[094] In this way, the transmission / reception of information in a wireless LAN system is performed in the form of a frame and, for this purpose, a PHY layer protocol data unit (PPDU) frame format is defined.

[095] A basic PPDU can include a Short Training Field (STF), a Long Training Field (LTF), a SIGNAL field (SIG), and a Data field. The most basic PPDU format (e.g., non-HT (High Throughput) shown in Figure 7) can consist only of Legacy STF (L-STF), Legacy LTF (L-LTF), Legacy SIG (L-SIG), and data fields. Additionally, depending on the PPDU format type (e.g., mixed-format HT PPDU, greenfield HT PPDU, VHT (Very High Throughput) PPDU, etc.), additional (or different) RL-SIG, U-SIG, non-legacy SIG fields, non-legacy STF, non-legacy LTF fields (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) etc., may be included between the L-SIG field and the data field.

[096] The STF is a signal for signal detection, automatic gain control (AGC), diversity selection, precise time synchronization and the like, and the LTF is a signal for channel estimation and frequency error estimation. The STF and LTF can be referred to as signals for synchronization and channel estimation of the OFDM physical layer.

[097] The SIG field may include various information related to PPDU transmission and reception. For example, the L-SIG field consists of 24 bits and may include a 4-bit rate field, a 1-bit reserved bit, a 12-bit length field, a 1-bit parity field, and a 6-bit tail field. The RATE field may include information about the modulation and encoding rate. Petition 870250093439, dated 10 / 13 / 2025, page 35 / 100 30 / 79 of data. For example, the 12-bit length field may include information about the length or duration of the PPDU. For example, the value of the 12-bit length field may be determined based on the PPDU type. For example, for non-HT, HT, VHT, or EHT PPDUs, the length field value may be determined as a multiple of 3. For example, for a HE PPDU, the length field value may be determined as a multiple of 3 + 1 or a multiple of 3 + 2.

[098] The data field may include a SERVICE field, a physical layer service data unit (PSDU), and a TAIL PPDU bit, and may also include padding bits if necessary. Some bits of the SERVICE field may be used for decoder synchronization at the receiving end. The PSDU corresponds to the MAC PDU defined in the MAC layer and may include data generated / used in the upper layer. The TAIL PPDU bit may be used to return the encoder to the 0 state. Padding bits may be used to adjust the length of a data field to a predetermined unit.

[099] A MAC PDU is defined according to various MAC frame formats, and a basic MAC frame consists of a MAC header, a frame body, and a Frame Check Sequence (FCS). The MAC frame may consist of MAC PDUs and be transmitted / received via the data portion of the PPDU frame format.

[0100] The MAC header includes a Frame Control field, a Duration / ID field, an Address field, and similar fields. The frame control field may include control information necessary for the transmission / reception of frames. The duration / ID field may be defined as a time for the transmission of a corresponding frame or similar. For details on the Sequence Control, QoS Control, and HT Control subfields of the MAC header, refer to the IEEE 802.11 standard document. Petition 870250093439, dated 10 / 13 / 2025, page 36 / 100 31 / 79

[0101] The Null Data PPDU (NDP) format refers to a PPDU format that does not include a data field. In other words, NDP refers to a frame format that includes the PPDU preamble in a general PPDU format (i.e., L-STF, L-LTF, L-SIG fields and, additionally, non-legacy SIG, non-legacy STF, non-legacy LTF, if present) and does not include the remaining part (i.e., data field).

[0102] Figure 7 is a diagram illustrating examples of PPDUs defined in the IEEE 802.11 standard to which this disclosure may be applied.

[0103] In standards such as IEEE 802.11a / g / n / ac / ax, several types of PPDUs have been used. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, LSTF, L-SIG and Data fields. The basic PPDU format may also be referred to as the non-HT PPDU format (as shown in Figure 7(a)).

[0104] The HT PPDU format (IEEE 802.11n) additionally includes the HT-SIG, HT-STF, and 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. In addition, a PPDU in the HT-greenfield format can be defined, which corresponds to a format consisting of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTF, and a data field, not including L-STF, L-LTF, and L-SIG (not shown).

[0105] An example of the VHT PPDU format (IEEE 802.11ac) additionally includes the VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in the basic PPDU format (as shown in Figure 7(c)).

[0106] An example of the HE PPDU format (IEEE 802.11ax) additionally includes the fields Repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), and Package Extension (PE) in the basic PPDU format (as shown in Figure 7(d)). Some fields may be omitted or their length may vary according to detailed examples of the HE PPDU format. For example, the HE-SIG-B field is included in the multi-user (MU) HE PPDU format, and HE-SIG-B is not included in the single-user (SU) HE PPDU format. Furthermore, the format Petition 870250093439, dated 10 / 13 / 2025, page 37 / 100 32 / 79 HE PPDU based on triggering (TB) does not include HE-SIG-B, and the HE-STF field length can vary up to 8 μs. The Extended Range SU PPDU (HE ER) format does not include the HE-SIG-B field, and the HE-SIG-A field length can vary up to 16 ps. For example, RL-SIG can be configured in the same way as L-SIG. The receiving STA can know whether the received PPDU is an HE PPDU or an EHT PPDU, which will be described later, based on the presence of RL-SIG.

[0107] The EHT PPDU format may include EHT MU (multi-user) in Figure 7(e) and EHT TB (shot-based) in Figure 7(f). The EHT PPDU format is similar to the HE PPDU format in that it includes RL-SIG followed by L-SIG, but may include U(universal)-SIG, EHT-SIG, EHT-STF and EHT-LTF after RL-SIG.

[0108] The PPDU EHT MU in Figure 7(e) corresponds to a PPDU that carries one or more data (or PSDU) for one or more users. That is, the PPDU EHT MU can be used for both SU and MU transmission. For example, the PPDU EHT MU can correspond to a PPDU for one receiving STA or for multiple receiving STAs.

[0109] The PPDU EHT TB in Figure 7(f) omits the EHT-SIG compared to the PPDU EHT MU. An STA that receives a trigger (e.g., trigger frame or triggered response schedule (TRS)) for MU UL transmission can perform UL transmission based on the PPDU EHT TB format.

[0110] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal Signal), and EHT-SIG fields can be encoded and modulated so that even legacy STAs can attempt demodulation and decoding, and can be mapped based on a specified subcarrier frequency range (e.g., 312.5 kHz). These can be referred to as pre-EHT modulated fields. Then, the EHT-STF, EHT-LTF, Data, and PE fields can be encoded and modulated to be demodulated and decoded by an STA that successfully decodes the non-legacy SIG (e.g., U-SIG and / or EHT-SIG) and obtains the information included in Petition 870250093439, dated 10 / 13 / 2025, page 38 / 100 33 / 79 field, and can be mapped based on a determined subcarrier frequency range (e.g., 78.125 kHz). These can be referred to as EHT modulated fields.

[0111] Similarly, in the HE PPDU format, the L-STF, L-LTF, LSIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields can be called pre-HE modulation fields, and the HE-STF, HE-LTF, Data, and PE fields can be called HE modulation fields. Additionally, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be called free VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields can be called VHT modulation fields.

[0112] The U-SIG included in the EHT PPDU format of Figure 7 can be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG can have a duration of 4 μs, and the U-SIG can have a total duration of 8 μs. Each U-SIG symbol can be used to transmit 26 bits of information. For example, each U-SIG symbol can be transmitted and received based on 52 data tones and 4 pilot tones.

[0113] U-GIS can be built in 20 MHz units. For example, if an 80 MHz PPDU is built, the U-GIS can be duplicated. That is, the same 4 U-GIS can be included in the 80 MHz PPDU. PPDUs that exceed the 80 MHz bandwidth can include different U-GIS.

[0114] For example, several unencoded bits can be transmitted through the U-SIG, the first U-SIG symbol (e.g., U-SIG-1 symbol) can transmit the first X bits of information from the total A bits of information, and the second U-SIG symbol (e.g., U-SIG-2 symbol) can transmit the remaining Y bits of the total A bit information. The A bit information (e.g., 52 unencoded bits) can include a CRC field (e.g., a 4-bit field of Petition 870250093439, dated 10 / 13 / 2025, p. 39 / 100 34 / 79 length) and a tail field (for example, a 6-bit length field). For example, the tail field can be used to terminate the convolutional decoder lattice and can be set to 0.

[0115] A bit information transmitted by U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG can be included in a new PPDU format not shown in Figure 7 (e.g., UHR PPDU format), and in the format of the U-SIG field included in the EHT PPDU format and in 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.

[0116] For example, the size of the version-independent bits of U-SIG can be fixed or variable. The version-independent bits can be assigned only to the U-SIG-1 symbol, or to both the U-SIG-1 and U-SIG-2 symbols. The version-independent bits and the version-dependent bits can be given various names, such as first control bit and second control bit.

[0117] For example, the U-SIG version-independent bits may include a 3-bit physical layer version identifier (PHY version identifier), and this information may indicate the PHY version (e.g., EHT, UHR, etc.) of the transmitted / received PPDU. The U-SIG version-independent bits may include a 1-bit UL / DL signaling field. The first value of the 1-bit UL / DL signaling field relates to UL communication, and the second value of the UL / DL signaling field relates to DL communication. The U-SIG version-independent bits may include information about the transmission opportunity length (TXOP) and information about the BSS color ID.

[0118] For example, the U-SIG version-dependent bits may include information that directly or indirectly indicates the PPDU type (e.g., SU PPDU, MU PPDU, TB PPDU, etc.). Petition 870250093439, dated 10 / 13 / 2025, page 40 / 100 35 / 79

[0119] The information necessary for the transmission and reception of PPDU can be included in the U-SIG. For example, the U-SIG can additionally include information about bandwidth, information about the MCS technique applied to the non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.), information indicating whether the DCM (dual carrier modulation) technique (e.g., a technique to obtain an effect similar to frequency diversity by reusing the same signal on two subcarriers) is applied to the non-legacy SIG, information about the number of symbols used for the non-legacy SIG, and whether the non-legacy SIG is generated across the entire band.

[0120] Some of the information required for the transmission and reception of PPDU may be included in the U-SIG and / or the non-legacy SIG (e.g., EHTSIG or UHR-SIG, etc.). For example, information about the type of non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information about the length of the non-legacy LTF and the length of the CP (cyclic prefix), information about the GI (guard interval) applicable to the non-legacy LTF, information about the preamble perforation applicable to the PPDU, information about the RU (resource unit) allocation, etc., may be included only in the U-SIG, only in the non-legacy SIG, or may be indicated by a combination of information included in the USIG and information included in the non-legacy SIG.

[0121] Preamble punching can mean transmitting a PPDU in which a signal does not exist in one or more frequency units within the PPDU bandwidth. For example, the frequency unit size (or preamble punch resolution) can be defined as 20 MHz, 40 MHz, etc. For example, preamble punching can be applied to a PPDU bandwidth of a predetermined size or more.

[0122] In the example in Figure 7, non-legacy GIS, such as HE-SIG-B and EHTSIG, can include control information for the receiving STA. A non-legacy GIS Petition 870250093439, dated 10 / 13 / 2025, p. 41 / 100 36 / 79 can be transmitted by at least one symbol, and a symbol can have a length of 4 μs. Information about the number of symbols used for EHTSIG may be included in previous GIS (e.g., HE-SIG-A, U-SIG, etc.).

[0123] Non-legacy GIS, such as HE-SIG-B and EHT-SIG, may include common fields and user-specific fields. Common fields and user-specific fields may be coded separately.

[0124] In some cases, common fields may be omitted. For example, in a compression mode where non-OFDMA (orthogonal frequency multiple access) is applied, the common field may be omitted, and multiple STAs may receive a PPDU (e.g., a PPDU data field) through the same frequency band. In an uncompressed mode where OFDMA is applied, multiple users may receive a PPDU (e.g., a PPDU data field) through different frequency bands.

[0125] The number of user-specific fields can be determined based on the number of users. A user block field can include up to two user fields. Each user field can be associated with a MU-MIMO allocation or it can be associated with a non-MU-MIMO allocation.

[0126] The common field may include a CRC bit and a tail bit, and the length of the CRC bit may be set to 4 bits, and the length of the tail bit may be set to 6 bits and defined as 000000. The common field may include RU allocation information. The RU allocation information may include information about the location of the RU to which multiple users (i.e., multiple receiving STAs) are assigned.

[0127] A RU can include multiple subcarriers (or tones). The RU can be used in the transmission of signals to multiple STAs based on the OFDMA technique. Additionally, the RU can be defined even in the transmission of a signal to a single STA. Resources can be allocated in RU units for non-STF fields. Petition 870250093439, dated 10 / 13 / 2025, page 42 / 100 37 / 79 legacy, non-legacy LTF and data.

[0128] An applicable RU size can be defined according to the bandwidth of the PPDU. The RU can be defined identically or differently for the applied PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80 MHz PPDU, the RU placement for HE PPDU and EHT PPDU may be different. The applicable RU size, the number of RUs and the RU location for each PPDU bandwidth, the location and number of the DC (direct current) subcarrier, the location and number of the null subcarrier, the location and number of the guard subcarrier, etc., can be referred to as a tone plan. For example, a high-bandwidth tone plan can be defined in the form of multiple iterations of a low-bandwidth tone plan.

[0129] RUs of various sizes can be defined as 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs, 996-tone RUs, 2x996-tone RUs, 3x996-tone RUs, etc. A multiple RU (MRU) is distinguished from a plurality of individual RUs and corresponds to a group of subcarriers composed of a plurality of RUs. For example, an MRU can be defined as 52+26 tones, 106+26 tones, 484+242 tones, 996+484 tones, 996+484+242 tones, 2X996+484 tones, 3X996 tones, or 3X996+484 tones. Additionally, a plurality of uniform rectilinear motions (URMs) that constitute a uniform rectilinear motion (URM) may or may not be continuous in the frequency domain.

[0130] The specific size of the RU can be reduced or expanded. Consequently, the specific size of each RU (i.e., the number of corresponding tones) in this disclosure is not limiting and is illustrative. Additionally, in this 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.

[0131] The names of each field in the PPDU formats in Figure 7 are Petition 870250093439, dated 10 / 13 / 2025, page 43 / 100 38 / 79 are examples, and the scope of this disclosure is not limited by the names. Furthermore, examples from this disclosure can be applied to the PPDU format illustrated in Figure 7, as well as to a new PPDU format in which some fields are excluded and / or some fields are added based on the PPDU formats in Figure 7. Multiple link operation

[0132] The following describes the multiple link (ML) operation supported by STA, according to this disclosure.

[0133] The STA (STA AP and / or STA non-AP) described in this disclosure may support multi-link (ML) communication. ML communication may refer to communication that supports multiple links. The links related to ML communication may include channels (e.g., 20 / 40 / 80 / 160 / 240 / 320 MHz channels) of a frequency band (e.g., 2.4 GHz band, 5 GHz band, 6 GHz band, etc.) in which the STA operates. The multiple links used for ML communication may be configured in various ways. For example, the multiple links supported by an STA for ML communication may belong to the same frequency band or may belong to different frequency bands. In addition, each link may correspond to a frequency unit of predetermined size (e.g., a channel, a subchannel, a RU, etc.). Furthermore, some or all of the multiple links may be frequency units of the same size or of different sizes.

[0134] When a STA supports multiple links, the transmit and receive devices that support each link can operate as a logical STA. That is, an MLD refers to a device that has one or more affiliated STAs as a logical entity and a single service access point (SAP) for a MAC data service and logical link control (LLC). A non-AP MLD refers to an MLD in which each STA affiliated with the MLD is a non-AP STA. An MLD Petition 870250093439, dated 10 / 13 / 2025, p. 44 / 100 39 / 79 non-AP multi-radio refers to a non-AP MLD that supports receiving or exchanging frames on more than one link simultaneously. An AP MLD refers to an MLD in which each STA affiliated with the MLD is an AP STA.

[0135] The Multiple Link Operation (MLO) can allow a non-AP MLD to discover, authenticate, associate, and configure multiple links with an AP MLD. Based on the supported capabilities exchanged during the association procedure, each link can allow channel access and frame exchange between the non-AP MLD and the AP MLD. An STA affiliated with an MLD can select and manage its capabilities and operational parameters independently of other STA(s) affiliated with the same MLD.

[0136] Through the multi-link configuration process, the MLD AP and / or the non-AP MLD can transmit and receive link-related information that the MLD can support. Link-related information may include one or more pieces of information about whether the MLD supports simultaneous transmit and receive (STR) operation or non-simultaneous transmit and receive (NSTR) operation, which allows simultaneous transmission and reception on multiple links, information about the number / upper limit of UL / DL links, information about the location / bandwidth / resources of UL / DL links, information about frame types (e.g., management, control, data, etc.) that are available or preferred on at least one UL / DL link, information about an ACK policy that is available or preferred on at least one UL / DL link, or information about a traffic identifier (TID) that is available on at least one UL / DL link.

[0137] An AP MLD (e.g., NSTR Mobile AP MLD) can define one link among multiple links as a primary link. The AP MLD can transmit beacon frames, polling response frames, and group-addressed data frames only on the primary link. The remaining link(s) of Petition 870250093439, dated 10 / 13 / 2025, page 45 / 100 40 / 79 Multiple links may be referred to as non-primary links. An AP MLD operating on a non-primary link may operate in such a way as not to transmit beacon frames or probe response frames. Furthermore, a non-AP MLD may perform frame exchanges during authentication, (re)association, and four-way handshake only on the primary link.

[0138] A configuration link is set to enabled if at least one traffic identifier (TID) is mapped to the link through the multi-link configuration process, and a configuration link can be set to disabled if no TID is mapped to the link. A TID must always be mapped to at least one configuration link unless admission control is used. By default, a TID is mapped to all configuration links, allowing all of them to be enabled.

[0139] When a link is enabled, it can be used for frame exchange, depending on the power state of the non-AP STA operating on the link. Only MSDUs or A-MSDUs with a TID mapped to the enabled link can be transmitted on the link. Management frames and control frames can only be transmitted on the enabled link.

[0140] When a link is disabled, it cannot be used for frame exchange, including management frames for DL ​​and UL.

[0141] During the process of configuring multiple links, the enabling / disabling of each link can be indicated by means of TID-to-Link mapping. TID-to-Link mapping can be performed in standard mapping mode and / or negotiation mapping mode.

[0142] One of the STAs affiliated with the MLD may provide information about one or more links other than the one on which it is located, for multiple link discovery (e.g., obtaining information about multiple links, including the corresponding link in a link) or multiple link configuration. Petition 870250093439, dated 10 / 13 / 2025, page 46 / 100 41 / 79 links (e.g., simultaneous association on multiple links through the exchange of association request / response frames on a link). A multi-link (ML) element can be defined to provide such information.

[0143] Figure 8 shows, by way of example, the structure of an ML element to which this disclosure can be applied.

[0144] In the ML element, the element ID field and the element ID extension field can have specific values ​​(for example, 255 and 107) indicating that it is an ML element, and the length field can have a value that indicates the length (for example, in octet units) of the remaining fields, excluding the element ID field and the length field.

[0145] The multi-link control field is defined as 2 octets in size and may include a 3-bit type subfield, a 1-bit reserved bit, and a 12-bit presence bitmap subfield. The type subfield may have a value indicating one of the following types: basic, polling request, reconfiguration, tunneled direct link configuration (TDLS), and priority access. The presence bitmap subfield indicates the presence or absence of various subfields within the common information field and may be defined in different formats depending on the various variants (or types) of the ML element.

[0146] The common information field is defined as having variable size and may include a 6-octet MLD MAC address subfield, which may have a value specifying the MAC address of the MLD to which the STA transmitting the basic ML element belongs. In addition, a link ID information subfield, a BSS parameter change count subfield, an average synchronization delay information subfield, an enhanced multiple link (EML) capacity subfield, an MLD capacity subfield, etc., may or may not be included in the common information field.

[0147] The link information field is defined to have size Petition 870250093439, dated 10 / 13 / 2025, page 47 / 100 42 / 79 variable, may include link-specific information and may be optionally present. When the link information field is present, it may include one or more sub-elements. The format and order of the sub-elements can be defined in several ways. As an example of an optional sub-element ID for a basic variant ML element, the sub-element ID value 0 corresponds to the profile name by STA and is extensible, the value 221 corresponds to the vendor-specific profile name and its extensibility can be determined by the vendor, and the remaining values ​​1-220 and 222-255 can be reserved.

[0148] The STA subfield per profile may include a 1-octet subelement ID subfield, a 1-octet length subfield, a 2-octet STA control subfield, a variable-length STA information subfield, and a variable-length STA profile subfield. The STA control subfield may include information such as the link ID, whether a full profile is included, whether a STA MAC address exists, etc. The STA information subfield may include information such as the STA MAC address. The STA profile subfield may include information included in a probe response frame body or probe request, information included in a (re)association response frame body or (re)association request, etc., depending on whether the reported STA is an AP STA or a non-AP STA.

[0149] The ML element format in Figure 8 is illustrative, and the order, name, size, etc. of the fields / subfields can be changed, additional fields / subfields can be defined in more detail, and some fields / subfields can be deleted. In summary, the common information field includes information common to the STAs in the MLD, and the link information field can include information specific to each STA / link (for example, in a profile subelement per STA, including a link ID corresponding to the STA). Petition 870250093439, dated 10 / 13 / 2025, p. 48 / 100 43 / 79

[0150] Figure 9 is a diagram illustrating an example of a high-level structure for an AP MLD to which this disclosure can be applied.

[0151] An AP MLD can include one or more APs. An AP MLD can have a high-level architecture, as illustrated in Figure 9. For example, the MLD can control various procedures / parameters common to multiple APs using a higher MAC sublayer. For example, authentication, association, sequence number (SN) / packet number (PN) allocation, power saving buffer for individually addressed frames, etc., can be commonly controlled between APs affiliated with an AP MLD.

[0152] Each affiliated AP (e.g., AP 1, ..., AP n) can provide upper MAC sublayer functionality for non-MLD data frames (e.g., traffic transmitted and received with non-MLD STAs, group-addressed MLD traffic, etc.). The AP MLD can provide upper MAC sublayer functionality for MLD data frames (e.g., traffic transmitted and received with MLD STAs) and provide MLD data to lower MAC sublayers of each affiliated AP. Each affiliated AP can provide PHY functionality (e.g., PHY 1, ..., PHY n). Both ML (MLO) and non-MLO operations can be performed on links corresponding to each PHY (e.g., link 1, ..., link n). MLD-based roaming

[0153] Before describing MLD-based roaming as described in this disclosure, we first describe a procedure in which a non-AP STA moves or roams from one AP to another in an existing wireless LAN system (e.g., BSS transition).

[0154] Figure 10 is a diagram to explain BSS transition in an existing wireless LAN system.

[0155] In the case of the FT (fast BSS transition) method, which is a representative example of BSS transition (or roaming), several processes, such as Petition 870250093439, dated 10 / 13 / 2025, page 49 / 100 44 / 79 authentication request / response and reassociation request / response are required between the FTO (FT originator) and the destination FTR to move from the current FTR (FT responder) to the destination FTR. That is, in the existing BSS transition method, a reassociation process is required within the same mobility domain.

[0156] Furthermore, after the process illustrated in Figure 10, several operating parameters, such as agreement related to BA (BlockAck) or SCS (Service Classification System) parameters, SN, EDCAF (EDCA function), etc., are reset. Therefore, the FTO must perform a large number of frame exchanges to the FT and must perform the agreement / configuration with a new FTR again. Consequently, the complexity and overhead of the FT process are high, and data loss may occur during the FT process. In this way, it is difficult to provide continuous roaming for STAs in existing wireless LAN systems.

[0157] This disclosure describes examples of seamless roaming based on MLD. For example, based on the AP MLD functionality described with reference to Figure 9, when a non-AP STA moves / roams between entities affiliated with a single MLD, the MLD-level parameters / configurations / agreements can be maintained without being reset.

[0158] In the following description, a STA that performs roaming is referred to as an RSTA, an AP currently associated is referred to as an OAP (old AP) or a first AP (or AP 1), and an AP to be newly associated is referred to as a NAP (new AP) or a second AP (or AP 2). In addition, MLD-based roaming, recently proposed in this disclosure, may simply be referred to as MLD roaming.

[0159] Additionally, each of the RSTA, OAP, and NAP can be an STA affiliated with different MLDs.

[0160] For example, an RSTA is a non-AP STA affiliated with a non-MLD Petition 870250093439, dated 10 / 13 / 2025, page 50 / 100 45 / 79 AP and can perform MLD roaming simultaneously / in conjunction with one or more other non-AP STAs.

[0161] For example, an OAP may be an AP STA affiliated with AP 1's MLD, and other APs may be affiliated with AP 1's MLD in addition to the OAP.

[0162] For example, a NAP may be an AP STA affiliated with AP 2 MLD, and other APs except a NAP may be affiliated with AP 2 MLD.

[0163] For example, an OAP and a NAP may be affiliated with the same higher MLD (either roaming MLD or AP 0 MLD). For example, the AP 1 MLD to which an OAP is affiliated may be affiliated with a higher MLD (e.g., AP 0 MLD), and the AP 2 MLD to which a NAP is affiliated may be affiliated with the same higher MLD (e.g., AP 0 MLD). Alternatively, among the APs affiliated with the AP 1 MLD, at least one AP including an OAP may be affiliated with a higher MLD (e.g., AP 0 MLD), and other APs may not be affiliated with the same higher MLD (e.g., AP 0 MLD) or may be affiliated with a different higher MLD or may not be affiliated with a higher MLD.Similarly, among the APs affiliated with AP MLD 2, at least one AP, including a NAP, may be affiliated with a higher MLD (e.g., AP MLD 0), and other APs may not be affiliated with the same higher MLD (e.g., AP MLD 0), or may be affiliated with a different higher MLD, or may not be affiliated with a higher MLD at all.

[0164] Furthermore, considering a non-AP MLD, at least one OAP affiliated with the AP's MLD 1 can be affiliated with a higher MLD, and at least one NAP affiliated with the AP's MLD 2 can be affiliated with the same higher MLD. For example, MLD-based roaming from a plurality of OAPs to a plurality of NAPs can be performed.

[0165] Next, the procedure for performing STA MLD-based roaming is described in detail.

[0166] Figure 11 is a diagram that illustrates an example of a method for Petition 870250093439, dated 10 / 13 / 2025, page 51 / 100 46 / 79 perform MLD-based roaming from a first STA, according to this disclosure. In Figures 11 and 12, the first STA can be affiliated with a non-AP MLD. Additionally, the first STA can be associated with a first AP affiliated with a first group (AP) to transmit and receive data.

[0167] The first STA can receive announcement information, including initial information related to the possibility of adding at least one link being supported for the first STA from the first access point (AP) affiliated with the first group (S1110).

[0168] In the present invention, the announcement information can be included in an MLD-based roaming element or in a reduced neighbor reporting (RNR) element included in a management frame. The MLD-based roaming element or RNR element can include a first subfield related to at least one group ID and a second subfield related to the first information (e.g., a temporary link addition subfield).

[0169] For example, based on the initial information indicating that adding at least one link is supported for the first STA by the second subfield, the first STA can add a link with another AP while maintaining a link with the first AP.

[0170] The first STA can transmit a request frame including the link ID of the second AP affiliated with the second group to the first AP (S1120).

[0171] In other words, the first STA can transmit a request frame to the first AP requesting MLD-based roaming to the second AP affiliated with the first group. The request frame can include a group ID associated with the second group to which the second AP is affiliated.

[0172] For example, Group 1 and Group 2 may be affiliated with the same AP MLD. To roam from a first AP included in Group 1 to a second AP included in Group 2, a first STA may transmit a frame of Petition 870250093439, dated 10 / 13 / 2025, page 52 / 100 47 / 79 request for the first AP.

[0173] In another example of this disclosure, each of the first group and the second group can be mapped to a separate AP MLD. For example, the first group can be mapped to the first AP MLD, and the second group can be mapped to the second AP MLD. That is, in the description of this disclosure, each group can be represented by a separate AP MLD. Furthermore, the first AP MLD and the second AP MLD can be affiliated with a separate group entity (or the entire AP MLD). The group entity (or the entire AP MLD) can collectively refer to a specific entity to which each AP MLD is affiliated.

[0174] The group object may correspond to the AP (entire) MLD illustrated in Figures 9, 13, and 18. For example, the group object may perform the function of the upper MAC sublayer of the MLD described with reference to Figure 9.

[0175] For example, the request frame may include second information requesting the addition or deletion of a link between the first STA and the second AP. Additionally, the request frame may include third information regarding whether the addition or deletion of a link between the first STA and the second AP is a temporary link addition or deletion.

[0176] For example, second and third information can be indicated via a single subfield included in the multi-link reconfiguration element of the request frame. For example, second and third information can be indicated via a single subfield as disclosed in Table 2, which will be described later.

[0177] As another example, the common information field or STA control field of the multi-link reconfiguration element may include a third subfield (e.g., a type subfield) related to the second information and a fourth subfield (e.g., a temporary subfield) Petition 870250093439, dated 10 / 13 / 2025, page 53 / 100 48 / 79 related to the third piece of information. That is, the second piece of information and the third piece of information can each be indicated by a separate subfield.

[0178] For example, based on a link addition request between the first STA and the second AP via the third and fourth subfields (for example, based on information requesting link addition between the first STA and the second AP being indicated by the third subfield and information requesting temporary link addition or deletion being indicated by the fourth subfield), as long as the link between the first STA and the first AP is connected, the link between the first STA and the second AP can be connected.

[0179] The first STA can receive a response frame including the link ID of the second AP from the first AP (S1130).

[0180] Based on the fact that the response frame includes information indicating acceptance of roaming to the second AP, an association process between the first STA and the second AP can be initiated. Additionally, the response frame may include a basic ML element, and the basic ML element may include AID and traffic identifier mapping information for the link to the first STA.

[0181] Based on the completion of the roaming procedure for the second AP (for example, the completion of the association procedure between the first STA and the second AP), the link between the first STA and the first AP can be deleted.

[0182] As an example of this disclosure, while a roaming procedure of a first STA is being performed, a roaming procedure of a second STA affiliated with a non-AP MLD may be performed. That is, when the roaming procedure of the first STA is being performed / completed, a roaming procedure of another STA affiliated with a non-AP MLD may be performed. As another example of this disclosure, a roaming procedure of a second STA may be Petition 870250093439, dated 10 / 13 / 2025, p. 54 / 100 49 / 79 performed while a roaming procedure of the first STA is being performed. That is, each of the first and second STAs affiliated with a non-AP MLD can perform a roaming procedure simultaneously. As another example, each STA affiliated with a non-AP MLD can perform a roaming procedure independently of the order.

[0183] As another example, the response frame may include a fourth piece of information related to a multi-link device (MLD) roaming timer. After the response frame is transmitted, the MLD roaming timer may begin to operate. Based on the expiration of the MLD roaming timer, the link between the first STA and the first AP may be deleted, and the first STA may communicate with the second associated AP.

[0184] The method performed by the first STA described in the example in Figure 11 can be performed by the first device (100) in Figure 1. For example, one or more processors (102) of the first device (100) in Figure 1 can receive advertisement information, including initial information related to the possibility of adding at least one link being supported for the first STA from a first AP affiliated with a first group via one or more transceivers (106). The one or more processors (102) can transmit a request frame, including a link ID of a second AP affiliated with a second group, to the first AP via one or more transceivers (106). One or more processors (102) can receive a response frame including a link ID of the second AP via one or more transceivers (106).

[0185] The memory (104) above can store instructions to perform the method described in the example in Figure 11 when executed by one or more processors (102).

[0186] Figure 12 is a diagram illustrating an example of a method in which a first AP according to the present disclosure supports roaming based Petition 870250093439, dated 10 / 13 / 2025, page 55 / 100 50 / 79 in MLD of a STA.

[0187] The first AP can transmit advertisement information, including initial information related to whether the addition of at least one link is supported for the first STA, to the first STA affiliated with the first group (S1210). That is, the first AP can transmit advertisement information, including parameters related to MLD-based roaming and information about whether simultaneous connection of two or more links from the first STA is supported, to the first STA.

[0188] The first AP can receive a request frame, including the link ID of the second AP affiliated with the second group, from the first STA (S1220). The request frame can include the link ID of the second AP and the group ID associated with the second group to which the second AP is affiliated. The AP can identify the AP to which the first STA intends to roam by means of the link ID and the group ID.

[0189] Additionally, the first AP can confirm that the first STA requests an additional (temporary) link connection with the second AP via the request frame.

[0190] The first AP can transmit a reply frame including the link ID of the second AP to the first STA (S1230). The first AP can transmit a reply frame containing information about roaming between the first STA and the second AP to the first STA. Consequently, a (temporary) link between the first STA and the second AP can be additionally established. Furthermore, an association procedure between the first STA and the second AP can be initiated by the reply frame.

[0191] The method performed by the first AP described in the example in Figure 12 can be performed by the second device (200) in Figure 1. For example, one or more processors (202) of the second device (200) in Figure 10 can transmit advertisement information, including the first information. Petition 870250093439, dated 10 / 13 / 2025, page 56 / 100 51 / 79 relating to the possibility of adding at least one link being supported for the first STA to the first STA through one or more transceivers (206). One or more processors (202) may receive a request frame including a link ID from a second AP affiliated to a second group of the first STA through one or more transceivers (206). One or more processors (202) may transmit a response frame including a link ID from the second AP to the first STA through one or more transceivers (206).

[0192] In addition, one or more memories (204) of the second device (200) may store instructions to perform the method described in the example in Figure 10 when executed by one or more processors (202).

[0193] The examples in Figures 11 and 12 may correspond to some of the various examples in this disclosure. Below, several examples from this disclosure, including the examples in Figures 11 and 12, will be described in more detail. Mode 1

[0194] Modality 1 describes exemplary operations of STAs and APs for MLD-based roaming. As an example of this disclosure, Figure 13 is a diagram illustrating an example of the structure and procedure of MLD-based roaming according to this disclosure.

[0195] As illustrated in Figure 13, APs 1, 2, and 3 can be affiliated with AP group 1, and APs 4 and 5 can be affiliated with AP group 2. Each AP group cannot be colocated, and the AP(s) affiliated with each AP group can be colocated in the same location or in similar locations. The fact that each AP is colocated can include not only the case where each AP is affiliated with exactly the same device, but also the case where each AP is colocated in a logically similar location, even if it does not belong to exactly the same device. Petition 870250093439, dated 10 / 13 / 2025, page 57 / 100 52 / 79

[0196] Because the AP MLD is a logical entity, it can be implemented as a specific physical device, but it refers to an MLD that encompasses affiliated APs regardless of location and performs / applies MLO. In other words, all APs affiliated with an AP group can include affiliated APs from an AP MLD.

[0197] As an example of the present disclosure, as illustrated in Figure 13, it is assumed that a non-AP MLD is in a multi-link configuration with an AP MLD, and STA 1 and STA 2 are each connected to AP 2 and AP 3 included in AP 1 group. When the non-AP MLD moves to an area where AP 2 group exists, roaming from AP 1 group to AP 2 group may be necessary. That is, through roaming, STA 1 can be connected to AP 4 and STA 2 can be connected to AP 5. In the present invention, during the roaming process, STA 1 and STA 2 can temporarily associate with AP 4 and AP 5, respectively, so that AP 4 and AP 5 can transmit frames to STA 1 and STA 2, respectively.

[0198] In the present invention, the non-AP MLD may include multiple affiliated STAs or may include one STA. The roaming operation / architecture illustrated in Figure 13 may be applied to a non-AP MLD including one or more affiliated STAs, and the roaming operation / architecture may also be applied to non-AP STA(s) that do not form the MLD.

[0199] In describing the present disclosure, roaming can be applied not only to movement between groups, but also to movement between APs within a specific AP group. Furthermore, MLD-based roaming, according to the present disclosure, can be performed by changing the links while maintaining the ML configuration without disassembling the existing ML configuration. For example, by maintaining the ML configuration for the upper MLDs of AP 1 and AP 2, an STA MLD can move from AP group 1 to AP group 2 by changing the links. Petition 870250093439, dated 10 / 13 / 2025, p. 58 / 100 53 / 79 within the upper MLD. Consequently, overhead and the risk of data loss can be reduced compared to the existing BSS transition.

[0200] The MLD-based roaming procedure may include setting the AP group ID (Mode 1-1), advertising the AP (Mode 1-2), and exchanging frames between the AP and the STA (Mode 1-3 Request and Mode 1-4 Response).

[0201] An ID can be assigned / defined for each AP group (consisting of AP(s) deployed in the same location). In this disclosure, the ID assigned / defined for each AP group will be referred to as the Group ID. For example, the Group ID can be defined as a unique ID within a single AP group. As another example, the Group ID can be defined as a unique ID for each AP group within the entire AP MLD.

[0202] The announcement may correspond to a procedure in which each AP affiliated with the higher MLD informs the STA(s) of information, such as whether MLD-based roaming is supported. Frame exchange between the STA and the AP may be performed based on this announcement information.

[0203] Frame exchange can correspond to a procedure of transmitting and receiving a frame that triggers / initiates MLD-based roaming between an AP and a STA. Through frame exchange, the information and configurations necessary for MLD-based roaming can be negotiated between the AP and the STA, and MLD-based roaming can be completed based on the negotiated information / configurations. Consequently, the STA can no longer operate with an OAP (old AP) (e.g., an AP included in AP group 1) and can operate with a NAP (new AP) (e.g., an AP included in AP group 2).

[0204] Thus, for MLD-based roaming to be activated / initiated, frame exchange between the STA and the AP is required. The frames Petition 870250093439, dated 10 / 13 / 2025, page 59 / 100 54 / 79 exchanged frames can correspond to management frames (e.g., beacons, (re)association requests / responses, polling requests / responses, action frames, etc.). For example, an action frame, which is a type of management frame, can be used for frame exchange.

[0205] In the examples described below, the frame transmitted by an STA (or AP) to request MLD roaming from an AP (or STA) is called the MLD roaming request frame, and the frame transmitted by an AP (or STA) to the STA (or AP) in response to the MLD roaming request frame is called the MLD roaming response frame.

[0206] Next, specific examples are described of the procedure for setting a group ID for each AP group, the procedure for requesting information about APs within each AP group, the notification procedure for MLD-based roaming, and the frame exchange procedure.

[0207] Additionally, a method is described for temporarily adding / removing links for MLD-based roaming. Consequently, an STA can maintain two links for a given period of time while performing MLD-based roaming. Mode 1 -1

[0208] Mode 1-1 relates to a procedure for defining a group ID for each group of APs. A moving MLD (or STA) may need to recognize at least one AP among the AP MLDs to which it is connected in order to perform roaming. Furthermore, when the MLD (or STA) requests roaming, the AP MLD can verify the data and management information to be transmitted from the OAP to the NAP, depending on which NAP the MLD (or STA) is moving to. Therefore, Mode 1-1 describes an identification method that takes into account affiliated AP(s) that are not located in the same location within the AP MLD (i.e., a method for defining an ID for roaming within the AP MLD). Petition 870250093439, dated 10 / 13 / 2025, page 60 / 100 55 / 79

[0209] An ID (i.e., a group ID) can be assigned to a group of APs colocated in the same location. For example, a unique group ID can be defined within an AP group (1-1-1 mode). As another example, a unique ID can be defined for each AP group within the entire AP MLD (1-1-2 mode). 1-1-1 Mode

[0210] The 1-1-1 Modality relates to a method for defining a unique ID within an AP group in an AP MLD. That is, the group ID can be unique within an AP group.

[0211] As an example of the present disclosure, the group ID can be defined as an integer greater than or equal to 0. For example, if the field indicating the group ID consists of 4 bits, the group ID can be defined as a value from 0 to 15. As another example, if the field indicating the group ID consists of 8 bits, the group ID can be defined as a value from 0 to 127.

[0212] For example, if the group ID is 0, APs with that group ID can be affiliated with the same group of APs deployed in the same location. That is, the MLD (or STA) can determine that APs with that group ID are deployed in the same location. Other group IDs can be mapped so that they can be uniquely identified for each group.

[0213] Additionally, since other APs in the multi-BSSID set (e.g., broadcast BSSID (i.e., TxBSSID) or non-broadcast BSSID (non-TxBSSID)) to which each AP in the AP group belongs also use the same physical resources, the same group ID can be assigned to the other APs. However, the AP MLD IDs of the AP MLDs to which the other APs belong may be different. Mode 1-1-2

[0214] The 1-1-2 Modality is related to a method for defining an ID Petition 870250093439, dated 10 / 13 / 2025, p. 61 / 100 56 / 79 unique within an AP MLD. That is, a group ID can be defined uniquely for each group of APs within the entire AP MLD.

[0215] As described above, the group ID can be defined as an integer greater than or equal to 0. For example, if the field indicating the group ID consists of 4 bits, the group ID can be defined as a number from 0 to 15. As another example, if the field indicating the group ID consists of 8 bits, the group ID can be defined as a number from 0 to 127.

[0216] Additionally, a group ID for APs performing roaming can be defined. That is, an MLD-to-MLD roaming ID can be defined between APs that have the corresponding group ID.

[0217] The existing MDID (Mobility Domain ID) field can be used to define the MLD roaming ID and / or group ID, but since the MDID field has a size of 2 octets, the MLD roaming ID and / or group ID can be defined in a smaller field. Mode 1-2

[0218] Mode 1-2 relates to an announcement procedure for roaming based on MLD based on the group ID.

[0219] Each AP included in the AP MLD can announce whether MLD-based roaming as described in this disclosure is possible and a group ID, etc. For example, each AP can transmit announcement information, including information indicating whether roaming is possible (e.g., “MLD roaming enabled”), a group ID, an MLD roaming ID, and / or temporary link addition / removal information. The information indicating whether roaming is possible can be composed of 1 bit, but is not limited to that. Furthermore, the group ID refers to the ID of the AP group that constitutes the AP MLD, as described above. That is, APs with the same group ID can be affiliated with the same AP group.

[0220] Advertisement information may be transmitted via a Petition 870250093439, dated 10 / 13 / 2025, page 62 / 100 57 / 79 management frame (e.g., a beacon frame, a polling frame, a (re)association response frame, etc.). For example, they can be included in an MLD roaming information element (IE) or in a reduced neighbor reporting (RNR) IE containing the advertisement information.

[0221] For example, the IE RNR may include a destination beacon transmission time information (TBTT) header, an operating class, a channel number, and a TBTT information set field. Among these, the TBTT information set may include one or more TBTT information fields. As illustrated in (a) of Figure 14, the TBTT information field may include the neighboring AP's TBTT offset, BSSID, short BSSID, BSS parameter, 20 MHz PSD (Power Spectral Density), and MLD parameter subfields. The MLD parameter may include, in addition to the MLD AP ID, link ID, BSS parameter change count, all included updates, and disabled link indication fields, an MLD roaming-enabled subfield corresponding to the advertisement information.

[0222] Additionally, the TBTT information field may include MLD roaming parameters, and the MLD roaming parameters may include advertisement information (i.e., MLD roaming enabled information, group ID information, MLD roaming ID, and temporary link addition information, etc.). Example (a) in Figure 14 corresponds to a case where the size of the MLD parameters subfield is not sufficient to include the advertisement information. The size of the MLD parameters subfield can be changed, but this may cause decoding problems for IEEE 802.11 be-based STAs.

[0223] In the present invention, since the fact that the MLD roaming parameter is included in the TBTT information field itself may mean that MLD roaming is possible, the enabled MLD roaming information may be omitted. Petition 870250093439, dated 10 / 13 / 2025, page 63 / 100 58 / 79

[0224] The subfield indicating additional temporary link information, as shown in (a) of Figure 1. Figure 14 may indicate whether a link can be temporarily added or removed for an STA. That is, the subfield indicating additional information about the temporary link may indicate that an STA supports having two or more links for a given period of time. For example, the subfield indicating additional information about the temporary link may consist of 1 bit, but is not limited to that.

[0225] As another example, as illustrated in (b) of Figure 14, information about enabling MLD roaming can be included in the MLD parameter subfield. In addition, the MLD roaming ID and / or the group ID can be transmitted via the MLD roaming parameter subfield or a separate field.

[0226] Additionally or alternatively, the notification information described above may be included in the basic multi-link IE. Mode 1-3

[0227] Request information to trigger / initiate MLD-based roaming can be included in a management frame (e.g., an MLD roaming request frame). For example, the MLD roaming request frame may have the exemplary format of Table 1. The format of Table 1 is exemplary, and some fields may be omitted or may include additional fields not illustrated. Table 1 Order Information 1 Category 2 UHR Action or Protected UHR Action 3 Dialog Token 4 Reconfiguration ML Elements

[0228] Category order 1 can be defined as a value that indicates Petition 870250093439, dated 10 / 13 / 2025, page 64 / 100 59 / 79 a category corresponding to the MLD roaming request frame. For example, the category may correspond to a new UHR action or a protected UHR action. This is an example, and the MLD roaming request frame can also be defined as a category with a different name. The UHR action or protected UHR action of order 2 can be defined as a value corresponding to the MLD roaming request.

[0229] The order 3 dialog token can be set as a value for matching requests and responses.

[0230] The ML reconfiguration element of order 4 corresponds to an element that includes information necessary for an MLD-based roaming request. This is an example, and elements / fields with other names containing information necessary for an MLD-based roaming request can be defined and used.

[0231] Figure 15 is a diagram illustrating an example of a reconfiguration ML element including request information in accordance with this disclosure.

[0232] Figure 15(a) illustrates an example of a presence bitmap field (e.g., Presence Bitmap in the Multiple Link Control field of Figure 8). The presence bitmap of a reconfiguration ML element may include information about the existence of an MLD MAC address subfield. Furthermore, the presence bitmap, according to the present disclosure, may indicate, through specific bit positions in the bitmap, whether an Enhanced ML Capability (EML) subfield exists in a common information field and whether an MLD Capability and Operation subfield exists in a common information field.

[0233] Figure 15(b) illustrates an example of a common information field (for example, the Common Information field in Figure 8). The common information field of the reconfiguration ML element may include a subfield of Petition 870250093439, dated 10 / 13 / 2025, page 65 / 100 60 / 79 common information length and an MLD MAC address subfield. Additionally, the common information field, according to this disclosure, may include both, one, or none of the EML capability subfields or the MLD capability and operation subfields (depending on the value in the corresponding bit position of the presence bitmap).

[0234] When more than one STA (especially in the case of non-AP MLD) migrating to NAP performs MLD-based roaming simultaneously, the EML capacity / MLD capacity and operation information may differ, so this information may be provided to the AP as MLD roaming request information.

[0235] Figure 15(c) illustrates an example of an STA control field (e.g., STA Control from Figure 8) included in an STA profile subelement of a link information field (e.g., Link Information field from Figure 8) of a reconfiguration ML element. Figure 15(d) illustrates an example of an STA information field (e.g., STA Information from Figure 8) included in an STA profile subelement of a link information field (e.g., Link Information field from Figure 8) of a reconfiguration ML element.

[0236] When more than one STA performs MLD-based roaming simultaneously, one or more profile sub-elements per STA may be included in the MLD roaming request frame.

[0237] The presence or absence of each subfield included in the STA information field can be indicated by the presence subfield of the corresponding subfield in the STA control field. For example, the presence subfield of the NSTR indication bitmap in the STA control field can indicate whether the NSTR indication bitmap subfield exists in the STA information field and, if present, the bitmap size can be indicated by the size subfield of the Petition 870250093439, dated 10 / 13 / 2025, page 66 / 100 61 / 79 bitmap NSTR of the STA control field. For example, the MLD roaming timer presence subfield of the STA control field can indicate whether the MLD roaming timer subfield exists in the STA information field.

[0238] The Link ID subfield value of the STA control field in Figure 15(c) can be set to a link identifier value corresponding to one of the NAPs (e.g., AP 2 affiliated with AP MLD 2 and, if present, other APs affiliated with AP MLD 2). For example, the Link ID subfield of the STA control field of the first profile subelement by STA can be set to a link identifier value corresponding to AP 2 affiliated with AP MLD 2, and the Link ID subfield of the STA control field of the second profile subelement by STA can be set to a link identifier value corresponding to another NAP affiliated with AP MLD 2.

[0239] The complete profile of the STA control field in Figure 15(c) may correspond to the complete STA information (i.e., all information included in the (re)association request frame). In the MLD-based roaming process, since a new STA is not associated with an AP affiliated with a higher MLD, but an existing STA moves between APs affiliated with the higher MLD, one can consider a case where the STA's capabilities and operational parameters do not change. Considering a case where the STA information is known by the higher MLD, the complete profile subfield in Figure 15(c) can be set to a value indicating that changed profile information (or partial profile information) is included.

[0240] For example, a partial profile corresponds to a case where the value of the full profile subfield of the STA control field is 0, and only fields / information elements that change in the STA profile field (for example, the STA Profile field in Figure 8) within the profile subelement by Petition 870250093439, dated 10 / 13 / 2025, page 67 / 100 62 / 79 STA can be included (i.e., information that changes compared to OAP when migrating to NAP). Alternatively, the full profile subfield of the STA control field can be changed to a name called changed profile subfield, and only fields / information elements that change in the STA profile field (i.e., information that changes compared to OAP when migrating to NAP) can be included when the subfield value is 1.

[0241] Alternatively, it can be considered that the STA’s capabilities and operating parameters are completely changed during the MLD-based roaming process. In this case, the value of the full profile subfield in Figure 15(c) can be set to 1, and the STA profile field can include complete information (e.g., all information included in the (re)association request form).

[0242] When a STA moves to a different AP, the STR or NSTR information for each link may differ from a non-AP MLD perspective, therefore an NSTR indication bitmap (e.g., the NSTR indication bitmap subfield of Figure 15(d)) may be included in the MLD roaming request frame.

[0243] The MLD roaming timer subfield can indicate when MLD-based roaming is completed and the STA no longer operates with the OAP and starts operating with the NAP. The MLD roaming timer value included in the request frame transmitted by the STA can be interpreted / used as reference information on the AP or the higher-level MLD.

[0244] Additionally or alternatively, the MLD roaming timer information may include a value for each one or more NAPs, or may include a value common to one or more NAPs. For example, a number of individual MLD roaming timer information corresponding to the number of NAPs may be included in the profile sub-element per STA of the request frame. Petition 870250093439, dated 10 / 13 / 2025, p. 68 / 100 63 / 79 MLD roaming. For example, a single piece of MLD roaming timer information common to one or more NAPs can be included in the common information field of the MLD roaming request form.

[0245] Additionally, suppose a temporary link addition is indicated for the STA (i.e., two or more multiple link connections are supported for the STA for a temporary period). In this case, the expiration of the MLD roaming timer may mean that the STA has completely terminated the connection with the OAP (i.e., deleted or temporarily deleted) and connected to the NAP. In this case, the MLD roaming timer can also be used as a deletion timer.

[0246] When the MLD roaming timer is applied in a common way to all APs, information about the MLD roaming timer can be included in the common information field. In this case, the presence or absence of the MLD roaming timer can be indicated in the common information field by means of an existence bitmap.

[0247] A group ID can be added to the reconfiguration ML element illustrated in Figure 15. The group ID refers to the ID of the group of APs to which the non-AP MLD (or STA) roams. 1-3-1 modality

[0248] As an example of the present disclosure, the group ID can be included in the common information field of the reconfiguration ML element. Specifically, as illustrated in (a) of Figure 16, if the group ID is included in the common information field of the reconfiguration ML element, this can be indicated by the presence bitmap of the reconfiguration ML element. As illustrated in (b) of Figure 16, when the group ID is included only in the common information field, roaming to AP(s) in the AP group with the same group ID can be requested via the roaming request frame. Petition 870250093439, dated 10 / 13 / 2025, page 69 / 100 64 / 79 of MLD.

[0249] That is, if a group ID is included in the common information field, a non-AP MLD (or STA) cannot request roaming to multiple group IDs, even within the same AP MLD. For example, if a group ID from a specific AP group is included in the common information field, a non-AP MLD (or STA) cannot request roaming to an AP within its current AP group or to an AP in a different AP group than the specific AP group. However, when performing inter-group roaming, the method according to the 1-3-1 modality may have reduced overhead compared to the case where a group ID is included in the link information field.

[0250] Additionally, the common information field of the ML reconfiguration element may include a type subfield as a field to include the ability to temporarily add / delete links for MLD-based roaming.

[0251] As an example of the present disclosure, the type subfield may consist of 2 bits, but is not limited to this. For example, if the type subfield consists of 2 bits, the type field may consist as shown in Table 2. However, this is one embodiment, and the type corresponding to the value of the type subfield may be defined as a different type. Furthermore, “temporary deletion” in Table 2 may be replaced by “deletion” corresponding to the value 1 of the type subfield. Table 2 Value of the field type: Type 0 add 1 delete 2 add temporarily 3 delete temporarily

[0252] If “Add” is indicated by the type subfield, this may mean Petition 870250093439, dated 10 / 13 / 2025, page 70 / 100 65 / 79 that the MLD non-AP STA requests an additional link connection with an AP (e.g., a NAP) of a specific AP MLD. If “Delete” is indicated by the type subfield, this may mean that the MLD non-AP STA requests disconnection from the current link (e.g., disconnection from the link with an OAP). If “Temporary Addition” is indicated by the type subfield, this may mean that the MLD non-AP STA requests the addition of a link with another AP (e.g., a NAP) different from the AP (e.g., an OAP) to which the current link is connected.

[0253] As another example of the present disclosure, as illustrated in (b) of Figure 16, the common information field (or body of the MLD roaming request frame) may include a temporary subfield and a type subfield as fields to include a temporary add / delete function of a link for MLD-based roaming. As an example, each of the temporary and type subfields may consist of 1 bit, and the type subfield may indicate “add” or “delete”. In addition, the temporary subfield may indicate whether the “add” or “delete” of the type subfield indicates temporary add or temporary delete.

[0254] For example, if “add” is indicated by the type subfield and the information indicating that the operation indicated by the type subfield is a temporary operation is indicated by the temporary subfield, this may correspond to “temporary addition” in Table 2.

[0255] When type and / or temporary subfields are included in the common information field, the STA(s) included in the non-AP MLD can only perform one operation for all APs. That is, when “add” is indicated by the type and / or temporary subfields, the STA(s) can only make one request to add a link for each AP(s). Mode 1-3-2

[0256] As an example of the present disclosure, as illustrated in (c) Petition 870250093439, dated 10 / 13 / 2025, page 71 / 100 66 / 79 of Figure 16, the reconfiguration ML element may include a link information field, and the link information field may include one or more profile sub-elements per STA. As illustrated in (d) of Figure 16, a roaming request to a specific AP affiliated with a specific AP group may be indicated by means of a Link ID and a Group ID included in the STA Control field of the profile sub-element per STA.

[0257] Additionally or alternatively, as illustrated in (d) of Figure 16, the STA control field may include a type and / or temporary subfield (i.e., the type and / or temporary subfield described in Mode 1-3-1). That is, the type and / or temporary subfield for temporarily adding / deleting a link for MLD-based roaming may be included in the format of the STA control field (included in the link information field). As the configuration and function of the type and / or temporary subfield have been described above, a redundant description will be omitted.

[0258] When type and / or temporary subfields are included in the link information field, the STA(s) included in the non-AP MLD can request different actions for each AP. That is, the STA(s) can request “temporary addition” for one AP and “deletion” for another AP through the type and / or temporary subfields.

[0259] Roaming can be requested for one or more APs corresponding to one or more group IDs via one or more STA sub-elements per profile. However, if roaming is requested based on the same group ID, the overhead may be higher than the method according to the 1-5-1 modality. 1-3-3 modality

[0260] As an example of the present disclosure, as illustrated in (a) of Figure 17, the STA control field of the STA profile subelement includes a group ID presence subfield, and the group ID presence subfield Petition 870250093439, dated 10 / 13 / 2025, p. 72 / 100 67 / 79 may indicate whether there is an AP group ID to which an AP corresponding to a specific link ID belongs. Additionally, as illustrated in (b) of Figure 17, the group ID may be included in the STA information field or in the STA profile field.

[0261] Roaming can be requested for one or more APs corresponding to one or more group IDs through one or more specific STA profile sub-elements. In particular, consider a case in combination with the method according to the 1-3-1 modality (i.e., the method of including the group ID in the common information field). In this case, if roaming is requested for APs corresponding to the same group ID, the group ID may not be included in the STA information field or the STA profile field, thus reducing overhead.

[0262] As another example, if a group ID is indicated through the common information field, roaming to the AP(s) corresponding to the same group ID may be implicitly indicated as requested. Consequently, the group ID may not be included in the STA information field or the STA profile field, and the Group ID presence field may also not be present. Mode 1-4

[0263] Response information for an MLD-based roaming request can be included in a management frame (e.g., an MLD roaming response frame). For example, the MLD roaming response frame might have the exemplary format of Table 3. The format of Table 3 is exemplary, and some fields may be omitted or may include additional fields that are not illustrated. Table 3 Order Information 1 Category Petition 870250093439, dated 10 / 13 / 2025, page 73 / 100 68 / 79 2 UHR Action or Protected UHR Action 3 Dialog Token 4 Status Code 5 Basic ML Element 6 Group Key Information 7 AID 8 Channel Switching Advertisement Element (optional) 9 Extended Channel Switching Advertisement Element (optional) 10 TID to Link Mapping Element (optional)

[0264] The MLD roaming response frame can include link-level parameters. For example, link-level parameters can include information needed to change the link while maintaining the ML configuration. Category 1 can be set to a value indicating the category corresponding to the MLD roaming response frame. For example, the category might correspond to a new UHR action or a protected UHR action. This is an example, and the MLD roaming response frame can also be set to a category with a different name.

[0265] The UHR action or the protected UHR action of order 2 can be defined as a value corresponding to the MLD roaming response.

[0266] The order 3 dialog token can be set as a value for matching requests and responses.

[0267] The order 4 status code can be set to one of several values ​​indicating success, failure, acceptance, rejection, unsupported, invalid, error, etc. Among the values ​​indicated by the status code, failure, rejection, unsupported, invalid, error, etc. can be set to different values ​​depending on the cause.

[0268] The basic ML element of order 5 may include information necessary for roaming related to the upper MLD (or roaming MLD) and the roaming destination AP / AP MLD (e.g., NAP or AP MLD including NAP). For this purpose, some fields of the basic ML element format Petition 870250093439, dated 10 / 13 / 2025, page 74 / 100 Existing fields 69 / 79 can be modified, omitted, or new fields can be added.

[0269] For example, the common information field of the basic ML element may have a format similar to the example common information field in Figure 8. In the present invention, the common information field of the basic ML element of the MLD roaming response frame may include common information or information corresponding to the NAP(s) through which one or more STAs perform MLD-based roaming.

[0270] For example, the link information field of the basic ML element may have essentially a format similar to the link information field example in Figure 8. In the present invention, the link information field of the basic ML element of the MLD roaming response frame may include one or more STA-profile sub-elements for corresponding APs when one or more STAs perform MLD-based roaming simultaneously. Thus, the STA control field, the STA information field, and / or the STA profile field included in the STA-profile sub-element of the link information field of the basic ML element of the MLD roaming response frame may include the following characteristics.

[0271] The link ID subfield of the STA control field can be set to a link ID value corresponding to the NAP.

[0272] A complete profile in the STA control field can correspond to the complete AP information (i.e., all information included in the (re)association response frame). When an STA performs MLD-based roaming between APs affiliated with the same higher MLD (or roaming MLD), a case can be considered where the AP's capabilities or operational parameters do not change. In this case, the complete profile subfield can be set to a value (e.g., 0) indicating that changed profile information (or partial profile information) is included. Consequently, the STA profile field in Petition 870250093439, dated 10 / 13 / 2025, page 75 / 100 70 / 79 profile sub-element per STA can only include fields / information elements that change (i.e., information that changes in a NAP compared to an OAP).

[0273] Alternatively, it can be considered that the AP's operational capabilities and parameters can be completely changed during the MLD-based roaming process. In this case, the value of the full profile subfield can be set to 1, and the STA profile field can contain complete information (e.g., all information included in the (re)association response frame).

[0274] Furthermore, based on the MLD roaming request frame type and / or the temporary subfield indicating (temporary) exclusion, the full profile for the corresponding AP may already be known, so the full profile subfield value may be indicated as 0.

[0275] The STA control field may include a field indicating whether an MLD roaming timer exists. If the existence of an MLD roaming timer is indicated, the STA information field may include an MLD roaming timer subfield. The “MLD Roaming Timer” subfield may indicate a point at which MLD-based roaming is completed and the STA no longer operates with an OAP, but rather with a NAP. The MLD roaming timer value included in the MLD roaming response frame may be set based on the MLD roaming timer value included in the MLD roaming request frame (e.g., to a value that changes when the requested timer value changes).For example, if the MLD roaming timer value requested by the STA is used as is and the status code value is set to a value indicating success / acceptance, the “MLD Roaming Timer” subfield may not be included in the MLD roaming response frame. Petition 870250093439, dated 10 / 13 / 2025, p. 76 / 100 71 / 79

[0276] Additionally or alternatively, MLD roaming timer information may include a value for each one or more NAPs, or may include a value common to one or more NAPs. For example, a number of individual MLD roaming timer information corresponding to the number of NAPs may be included in the profile sub-element per STA of the MLD roaming response frame. For example, a single MLD roaming timer information common to one or more NAPs may be included in the common information field of the MLD roaming response frame.

[0277] Additionally, the basic ML element can include a group ID.

[0278] As an example of the present disclosure, a group ID may be included in the common information field of a basic ML element, such as in Mode 1-3-1, and the existence of the group ID in the common information field may be indicated by means of the presence bitmap subfield of the basic ML element. Consequently, the roaming MLD response frame may include information about AP(s) affiliated to the same group of APs with the group ID indicated by means of the common information field.

[0279] As an example of the present disclosure, when an MLD roaming response frame including a group ID (i.e., when the group ID is included in the link information field) is transmitted as in Mode 1-3-2, the group ID may be included in the link information field of the basic ML element of the MLD roaming response frame.

[0280] Specifically, the link information field of the basic ML element may include one or more profile sub-elements per STA, and the STA control field of each of the one or more profile sub-elements per STA may include a link ID and a group ID (i.e., an ID of a group of APs).

[0281] Information about one or more APs corresponding to one or more group IDs can be provided through one or more profile sub-elements. Petition 870250093439, dated 10 / 13 / 2025, p. 77 / 100 72 / 79 specific to STA. However, when providing information about AP(s) with the same group ID, the overhead may be greater than the method according to the 1-5-1 modality.

[0282] As another example of this disclosure, the STA control field of each profile sub-element per STA may include information indicating whether a group ID exists in each or more profile sub-elements per STA (i.e., group ID presence information).

[0283] That is, by means of the group ID existence information of the STA control field included in the STA sub-element by profile, it can be indicated whether the ID (i.e., group ID) of the AP group to which the AP corresponding to the link ID included in the STA control field is affiliated exists in the STA profile sub-element. In the present invention, the group ID can be included in the STA information field or in the STA profile field of the STA profile sub-element.

[0284] Information about one or more APs corresponding to one or more group IDs can be provided through one or more profile sub-elements per STA.

[0285] Additionally or alternatively, the 1-3-1 modality method (i.e., the method in which the group ID is included in the common information field) and the 1-3-3 modality method (i.e., information indicating whether the group ID exists in the STA control field) can be combined. If only information about APs corresponding to the same group ID is provided, the group ID does not need to be included in the specific STA profile sub-element, thus reducing overhead.

[0286] As an example of this disclosure, when a unique ID is defined within a group of APs in the AP MLD, as described in Mode 1-1-1, if the group ID is 0, the group ID may be omitted. That is, when the group ID does not exist, the AP that receives the MLD roaming request frame Petition 870250093439, dated 10 / 13 / 2025, p. 78 / 100 73 / 79 may implicitly determine that the request form is a request for information about other APs pertaining to the group to which it belongs.

[0287] As another example of this disclosure, if a group ID is included in the common information field, the STA may implicitly determine that the information included in the MLD roaming response frame is information about the AP(s) corresponding to the same group ID. Consequently, the presence field of the group ID may not be included in the MLD roaming response frame.

[0288] Group key information of order 6 can be defined as a value that indicates group key information for NAPs. Because the group key can be different for each link, it is necessary to provide group key information for NAPs. For example, a field corresponding to group key information can include a subfield that indicates the length of a subfield of group key information and a subfield defined as a value of the group key information. Group key information can include an MLO GTK (group temporal key) KDE (key data encapsulation) format, an MLO IGTK (group integrity temporal key) KDE format, an MLO BIGTK (beacon integrity temporal key) KDE format, etc., including a NAP link identifier.

[0289] The AID information in step 7 can manage AIDs for each group. Since the total AID space is limited, AIDs can be managed by AP group. That is, when roaming to another group, a separate AID can be assigned. However, when roaming to another group and assigning the same AID, or when all the AID space is managed by the MLD AP as before, the AID information in step 7 may not exist.

[0290] Channel switching advertisement element information and extended channel switching advertisement element information Petition 870250093439, dated 10 / 13 / 2025, page 79 / 100 Sequences 8 and 9 (74 / 79) can be omitted from the MLD roaming response frame when all APs with MLD-based roaming enabled operate on the same channel. When MLD-based roaming is performed on a different channel, channel information can be provided via the channel switching advertisement element (extended). Alternatively, the channel switching advertisement element (extended) can be included in the STA information / profile field of the basic ML element of sequence 5.

[0291] The TID to Link mapping information of order 10 can be used to map TIDs in advance via TID to Link mapping for a newly connected link. If TID to Link mapping is not performed separately, the default mapping can be applied to the newly connected link. If the default mapping mode is applied, all TIDs can be mapped to links configured for DL ​​and UL, and all configured links can be enabled.

[0292] Additionally, the AP MLD can include the MLD roaming timer of the reconfiguration ML element described above in the MLD roaming response frame. That is, the AP MLD can control the MLD-based roaming procedure and therefore can set / indicate the MLD roaming timer. For example, suppose the STA transmits an MLD roaming request frame that does not include the MLD roaming timer, or the MLD roaming timer information transmitted by the STA is determined by the AP to be inadequate. In this case, the AP MLD can transmit an MLD roaming response frame including information to set the MLD roaming timer for the STA.

[0293] In the present invention, the expiration of the MLD roaming timer may mean that the time when the STA no longer performs multiple operations with the OAP and performs multiple operations with the NAP has already passed, to Petition 870250093439, dated 10 / 13 / 2025, page 80 / 100 75 / 79 as MLD-based roaming is completed. For example, suppose the STA transmits an MLD roaming request frame, including a request to add a temporary link with the NAP. In this case, if the MLD roaming timer expires, the STA can disconnect from the OAP (i.e., “delete” or “temporarily delete”) the link and perform a connection with the NAP.

[0294] If the MLD roaming timer is commonly applied to all APs, information about the MLD roaming timer can be included in the common information field of the reconfiguration / default ML element, as illustrated in (b) of Figure 16. Additionally, information indicating whether the MLD roaming timer exists in the common information field can be included in the presence bitmap subfield of the reconfiguration / default ML element. Procedure for Exchanging Roaming Request / Response Frames (MLD)

[0295] As an example of the present disclosure, Figure 18 illustrates a procedure for performing MLD-based roaming. It is assumed that STA 1, affiliated with a non-AP MLD, is currently connected to AP 1 of AP group 1, and STA 2, affiliated with a non-AP MLD, is currently connected to AP 2 of AP group 1. In the present invention, as STA 1 and STA 2 move from AP group 1 to AP group 2, STA 1 can perform a roaming procedure to AP 4 of AP group 1, and STA 2 can perform a roaming procedure to AP 5 of AP group 2.

[0296] STA 1 can exchange an MLD roaming request / response frame with AP 1 to temporarily connect to AP 4 while connected to AP 1 (i.e., to add a temporary link). In the present invention, the MLD roaming request frame can include information requesting a temporary link connection with AP 4. In the present invention, the Petition 870250093439, dated 10 / 13 / 2025, page 81 / 100 76 / 79 MLD roaming request frame may include a link ID of AP 4 and a group ID of the AP 2 group to which AP 4 is affiliated. Consequently, AP 1 may transmit a basic ML element, including information indicating that it approves the MLD-based roaming request and information about AP 4 to STA 1 via the MLD roaming response frame.

[0297] Similar to the method described above, STA 2 can exchange MLD roaming request / response frames with AP 2 to temporarily connect to AP 5 while connected to AP 2 (i.e., to add a temporary link). In the present invention, the MLD roaming request frame can include information requesting a temporary link connection with AP 5. In the present invention, the MLD roaming request frame can include a link ID of AP 5 and a group ID of the AP 2 group to which AP 5 is affiliated. Consequently, AP 2 can transmit a basic ML element, including information indicating that it approves the MLD-based roaming request and information about AP 5 to STA 2 via the MLD roaming response frame.

[0298] When the procedure described above is completed, STA 1 can be temporarily connected to AP 1 and AP 4, and STA 2 can be temporarily connected to AP 2 and AP 5. Consequently, STA 1 can transmit and receive data to and from AP 1 and AP 4, and STA 2 can transmit and receive data to and from AP 2 and AP 5.

[0299] Next, STA 1 can perform a (temporary) disconnection operation with AP 1, and STA 2 can perform a (temporary) disconnection operation with AP 2. Consequently, STA 1 can complete an ML-based roaming procedure to AP 4, and STA 2 can complete an ML-based roaming procedure to AP 5.

[0300] The procedure described above relates to a procedure Petition 870250093439, dated 10 / 13 / 2025, p. 82 / 100 77 / 79 for a STA to temporarily add a link and delete a link with an OAP. The MLD roaming timer can be used in the procedure for adding and temporarily deleting a link.

[0301] For example, STA 1 and STA 2 can transmit and receive MLD roaming request / response frames to and from AP 1 and AP 2, respectively. STA 1 and STA 2 can request the temporary addition of a link to AP 4 and AP 5, respectively, via the MLD roaming request frame. In the present invention, as described above, an MLD roaming timer can be set via an MLD roaming response frame by a non-AP MLD or an AP MLD. After successful transmission of the MLD roaming response frame, the MLD roaming timer can operate. When the MLD roaming timer expires, the link between STA 1 and AP 1 can be deleted and the link between STA 1 and AP 4 can be fully connected. Furthermore, when the MLD roaming timer expires, the link between STA 2 and AP 2 can be deleted, and the link between STA 2 and AP 5 can be fully connected.

[0302] Through the procedure described above, each STA included in the non-AP MLD can transmit and receive data simultaneously with the previously connected AP and the AP with which it is attempting to roam while performing the MLD roaming procedure. This allows for a more efficient and seamless MLD-based roaming procedure.

[0303] The embodiments described above are those in which elements and features of this disclosure are combined in a predetermined way. Each element or feature should be considered optional unless explicitly stated otherwise. Each element or feature may be implemented in a way that is not combined with another element or feature. In addition, an embodiment of this disclosure may include the combination of Petition 870250093439, dated 10 / 13 / 2025, page 83 / 100 78 / 79 a portion of elements and / or features. The order of operations described in the embodiments of this disclosure may be altered. Some elements or features of one embodiment may be included in another embodiment or may be replaced by a corresponding element or feature from another embodiment. It is evident that an embodiment may include a combination of claims without an explicit dependency relationship in the claims or may be included as a new claim by means of an amendment after application.

[0304] It is evident to a person skilled in the relevant art that the present disclosure can be implemented in another specific form, within a scope that does not exceed an essential feature of the present disclosure. Consequently, the above detailed description should not be interpreted restrictively in all respects and should be considered illustrative. The scope of this disclosure shall be determined by the reasonable interpretation of an appended claim, and all changes within an equivalent scope of this disclosure are included in the scope of this disclosure.

[0305] The scope of this disclosure includes machine-executable software or commands (e.g., an operating system, an application, firmware, a program, etc.) that perform an operation according to a method of various modalities on a device or computer and a non-transient, computer-readable medium on which such software or command, etc., is stored and executable on a device or computer. A command that can be used to program a processing system that performs a function described in this disclosure may be stored on a storage medium or on a computer-readable storage medium, and a function described in this disclosure may be implemented using a computer program product that includes such a storage medium. A storage medium may include high-speed random-access memory, such as DRAM, SRAM, DDR RAM, or Petition 870250093439, dated 10 / 13 / 2025, page 84 / 100 79 / 79 other random access solid-state memory device, but not limited to, and may include non-volatile memory such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. A memory optionally includes one or more storage devices positioned remotely from the processor(s). A memory, or alternatively, one or more non-volatile memory devices within a memory, includes a computer-readable non-transient storage medium.A resource described in this disclosure may be stored in any machine-readable media to control the hardware of a processing system and may be integrated into software and / or firmware that allows a processing system to interact with another mechanism using an output of an embodiment of this disclosure. Such software or firmware may include, but is not limited to, application code, a device driver, an operating system, and an execution environment / container. Industrial Applicability

[0306] The method proposed in this disclosure was described focusing on examples applied to IEEE 802.11-based systems, but it can be applied to various wireless LANs or wireless communication systems, in addition to IEEE 802.11-based systems. Petition 870250093439, dated 10 / 13 / 2025, page 85 / 100

Claims

1 / 4 CLAIMS 1. Method performed by a multi-link device (MLD) without an access point (AP) CHARACTERIZED in that it comprises: receiving, by a first non-AP station (STA) affiliated with the non-AP MLD from a first AP MLD, a first frame including information relating to a continuous transition of the basic service set (BSS); transmitting, by the first non-AP STA to the first AP MLD, a continuous BSS transition request frame for a continuous BSS transition procedure from the first AP MLD to a second AP MLD;and receive, by the first non-AP STA from the first AP MLD, a Continuous BSS Transition Response Frame including a status value set to SUCCESS, wherein the Continuous BSS Transition Response Frame includes a timer related to a Continuous BSS Transition and a group key of at least one link on the second AP MLD, and wherein, based on the expiration of the MLD roaming timer, the Continuous BSS Transition procedure from the first AP MLD to a second AP MLD is completed.

2. Method, according to claim 1, CHARACTERIZED in that: the information relating to the continuous BSS transition includes at least one identifier (ID) relating to the continuous BSS transition and information relating to whether the continuous BSS transition is supported.

3. Method, according to claim 1, CHARACTERIZED in that: the continuous BSS transition request framework includes third-party information relating to whether an addition or deletion of a link between the first non-AP STA Petition 870250079890, dated 05 / 09 / 2025, page 17 / 20 2 / 4 and the second AP MLD is a temporary link addition or deletion.

4. Method, according to claim 3, CHARACTERIZED in that: the continuous BSS transition request frame includes a multi-link reconfiguration element, and a common information field or STA control field of the multi-link reconfiguration element includes a third subfield related to second information requesting the addition or deletion of a link between the first non-AP STA and the second AP MLD and a fourth subfield related to third information.

5. Method, according to claim 4, CHARACTERIZED in that: based on an addition of a link between the first non-AP STA and the second AP MLD being requested through the third subfield and the fourth subfield, the link between the first non-AP STA and the second AP MLD is connected while the link between the first non-AP STA and the first AP MLD is connected.

6. Method, according to claim 5, CHARACTERIZED in that: based on the continuous BSS transition procedure for the second AP MLD being completed, the link between the first non-AP STA and the first AP MLD is deleted.

7. Method according to claim 1, CHARACTERIZED in that: the continuous BSS transition request frame includes a medium access control (MAC) address of the second AP MLD.

8. Method, according to claim 1, CHARACTERIZED in that: Petition 870250079890, dated 05 / 09 / 2025, page 18 / 20 3 / 4 the continuous BSS transition response frame includes a basic ML element, and the basic ML element includes AID and traffic identifier mapping information related to the first non-AP STA.

9. First station (STA) affiliated with a multi-link device (MLD) without an access point (AP) CHARACTERIZED by the fact that it comprises: at least one transceiver; and at least one processor coupled to at least one transceiver, wherein the at least one processor is configured to: receive, from a first access point (AP) MLD, a first frame including initial information related to a continuous BSS transition, through at least one transceiver; transmit, to the first AP MLD, a continuous BSS transition request frame for a continuous BSS transition procedure from the first AP MLD to a second AP MLD, through at least one transceiver;and receive, from the first AP MLD, a continuous BSS transition response frame including a status value defined as, through at least one transceiver, wherein the continuous BSS transition response frame includes a timer related to a continuous BSS transition and a group key from at least one link on the second AP MLD, and wherein, based on the expiration of the MLD roaming timer, the continuous BSS transition procedure from the first AP MLD to a second AP MLD is completed.

10. First access point (AP) affiliated with a first multi-link AP device (MLD) CHARACTERIZED in that it comprises: at least one transceiver; and Petition 870250079890, dated 05 / 09 / 2025, page 19 / 20 4 / 4 at least one processor coupled to at least one transceiver, wherein the at least one processor is configured to: transmit, to a first station (STA) affiliated with a non-AP MLD, a first frame including information relating to a continuous transition of the Basic Services Set (BSS), through at least one transceiver; receive, from the first STA, a continuous BSS transition request frame for a continuous BSS transition procedure from the first AP MLD to a second AP MLD, through at least one transceiver;and transmit, to the first STA, a continuous BSS transition response frame including a status value set to SUCCESS, through at least one transceiver, wherein the continuous BSS transition response frame includes a timer related to a continuous BSS transition and a group key from at least one link on the second AP MLD, and wherein, based on the expiration of the MLD roaming timer, the continuous BSS transition procedure from the first AP MLD to a second AP MLD is completed. Petition 870250079890, dated 05 / 09 / 2025, p. 20 / 20;

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