Method and apparatus for establishing association with multiple access points in wireless LAN system

Abstract

The present disclosure discloses a method and apparatus for establishing association with a plurality of access points (APs) in a wireless LAN system. According to one embodiment of the present disclosure, a method performed by a station (STA) in a wireless local area network system may comprise the steps of: receiving, from a specific AP, a beacon frame including information related to an AP set to which the specific AP belongs; transmitting, to the specific AP, a first frame for requesting an association between the STA and a plurality of APs belonging to the AP set; and receiving, from the specific AP, a second frame corresponding to the response to the first frame. Here, at least one of the first frame and the second frame may include association-related information for each AP included in the plurality of APs.

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for establishing an association with multiple access points (APs) in a wireless local area network (WLAN) system. Background Art

[0002] New technologies for increasing transmission rate, increasing bandwidth, increasing reliability, reducing errors, and reducing latency have been introduced for wireless local area network (WLAN). Among WLAN technologies, the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series of standards can be referred to as Wi-Fi. For example, technologies recently introduced to WLAN include very high throughput (VHT) enhancements of the 802.11ac standard and high efficiency (HE) enhancements of the IEEE 802.11ax standard.

[0003] To provide a more advanced wireless communication environment, improved technologies for extremely high throughput (EHT) are being discussed. For example, technologies for multiple-input multiple-output (MIMO) and multi-access point (AP) coordination that support increased bandwidth, efficient use of multiple bands, and increased spatial streams are being studied, and specifically, various technologies are being studied to support low-latency or real-time services. In addition, new technologies are being discussed to support ultra-high reliability (UHR), including improvements or extensions of EHT technologies. Summary of the Invention

[0004] Technical Problem

[0005] A technical objective of the present disclosure is to provide a method and apparatus for establishing an association with multiple access points (APs) in a wireless local area network (WLAN) system.

[0006] The technical objectives to be achieved by the present disclosure are not limited to the above technical objectives, and those skilled in the art can clearly understand other technical objectives not described herein through the following description.

[0007] Technical Solution

[0008] According to an aspect of the present disclosure, a method performed by a station (STA) in a wireless LAN system may include: receiving, from a specific access point (AP), a beacon frame including information related to an AP set to which the specific AP belongs; transmitting, to the specific AP, a first frame for requesting an association between a plurality of APs belonging to the AP set and the STA; and receiving, from the specific AP, a second frame corresponding to a response to the first frame. Here, at least one of the first frame or the second frame may include association-related information for each AP included in the plurality of APs.

[0009] According to another aspect of the present disclosure, a method performed by an access point (AP) in a wireless local area network (WLAN) system may include: sending a beacon frame including information related to an AP set to which the AP belongs to a station (STA); receiving, from the STA, a first frame for requesting an association between a plurality of APs belonging to the AP set and the STA; and sending, to the STA, a second frame corresponding to a response to the first frame. Here, at least one of the first frame or the second frame may include association-related information for each of the plurality of APs included in the plurality of APs.

[0010] Technical effects

[0011] According to the present disclosure, a method and apparatus for establishing an association with a plurality of access points (APs) in a wireless local area network (WLAN) system can be provided.

[0012] According to the present disclosure, there are the following advantages: Based on the association with a plurality of APs, the delay that may occur when the STA roams from an existing AP to another AP can be reduced.

[0013] The effects that can be achieved by the present disclosure are not limited to the above effects, and those skilled in the relevant art can clearly understand other effects not described herein through the following description. Brief description of the drawings

[0014] The drawings included as part of the specific embodiments for understanding the present disclosure provide embodiments of the present disclosure and describe the technical features of the present disclosure together with the specific embodiments.

[0015] Figure 1 Illustrates a configuration block diagram of a wireless communication device according to an embodiment of the present disclosure.

[0016] Figure 2 Is a diagram illustrating an exemplary structure of a WLAN system to which the present disclosure can be applied.

[0017] Figure 3 Is a diagram for describing a link establishment process to which the present disclosure can be applied.

[0018] Figure 4 Is a diagram for describing a backoff process to which the present disclosure can be applied.

[0019] Figure 5 Is a diagram for describing a CSMA / CA-based frame transmission operation to which the present disclosure can be applied.

[0020] Figure 6 Is a diagram for describing an example of a frame structure used in a WLAN system to which the present disclosure can be applied.

[0021] Figure 7Is a diagram illustrating an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0022] Figure 8 Is a schematic diagram showing an exemplary relationship between a multi-BSSID set and a multi-link device to which the present disclosure can be applied.

[0023] Figure 9 Is a schematic diagram showing an example of a multi-AP scheme to which the present disclosure can be applied.

[0024] Figure 10 Is a schematic diagram showing an example for explaining roaming to which the present disclosure can be applied.

[0025] Figure 11 Is an example of a multi-AP set according to an embodiment of the present disclosure.

[0026] Figure 12 Is an example of a target beacon transmission time (TBTT) information field in a reduced neighbor report (RNR) element for multi-association according to an embodiment of the present disclosure.

[0027] Figure 13 Is an example of a multi-AP element for multi-association according to an embodiment of the present disclosure.

[0028] Figure 14 Illustrates an association process for multi-association according to an embodiment of the present disclosure.

[0029] Figure 15 Is a schematic diagram for explaining an STA establishing a multi-association operation according to an embodiment of the present disclosure.

[0030] Figure 16 Is a schematic diagram for explaining an AP establishing a multi-association operation according to an embodiment of the present disclosure. Detailed implementation manners

[0031] Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description to be disclosed through the drawings is to describe exemplary embodiments of the present disclosure, rather than indicating the only embodiments in which the present disclosure can be implemented. The following detailed description includes specific details to provide a complete understanding of the present disclosure. However, those skilled in the relevant art know that the present disclosure can be implemented without these specific details.

[0032] In some cases, known structures and devices may be omitted, or may be shown in the form of block diagrams based on the core functions of each structure and device in order to prevent the concepts of the present disclosure from being ambiguous.

[0033] In the present disclosure, when an element is referred to as being "connected", "combined", or "linked" to another element, it may include both an indirect connection relationship and a direct connection relationship in which yet another element exists therebetween. Further, in the present disclosure, the terms "comprising" or "having" specify the presence of the recited features, steps, operations, components, and / or elements, but do not preclude the presence or addition of one or more other features, stages, operations, components, elements, and / or groups thereof.

[0034] In the present disclosure, terms such as "first", "second", etc. are used only to distinguish one element from another element and do not limit the element, unless otherwise specified, and do not limit the order or importance, etc. between the elements. Thus, within the scope of the present disclosure, the first element in one embodiment may be referred to as the second element in another embodiment, and similarly, the second element in one embodiment may be referred to as the first element in another embodiment.

[0035] The terms used in the present disclosure are for the purpose of describing particular embodiments and are not intended to limit the claims. As used in the description of the embodiments and the appended claims, the singular forms are intended to include the plural forms unless the context clearly indicates otherwise. The term "and / or" as used in the present disclosure may refer to one of the related listed items or may mean that it refers to and includes any and all possible combinations of two or more of them. Further, unless otherwise specified, the " / " between words in the present disclosure has the same meaning as "and / or".

[0036] Examples of the present disclosure may be applied to various wireless communication systems. For example, examples of the present disclosure may be applied to a wireless LAN system. For example, examples of the present disclosure may be applied to a wireless LAN based on the IEEE 802.11a / g / n / ac / ax standards. Further, examples of the present disclosure may be applied to a wireless LAN based on the newly proposed IEEE 802.11be (or EHT) standard. Examples of the present disclosure may be applied to a wireless LAN based on the IEEE 802.11be version 2 standard corresponding to additional enhancement technologies of the IEEE 802.11be version 1 standard. Additionally, examples of the present disclosure may be applied to a next-generation standard-based wireless LAN after IEEE 802.11be. Further, examples of the present disclosure may be applied to a cellular wireless communication system. For example, it may be applied to a cellular wireless communication system based on long-term evolution (LTE) technology and 5G new radio (NR) technology based on the 3rd Generation Partnership Project (3GPP) standards.

[0037] Hereinafter, the technical features to which examples of the present disclosure can be applied will be described.

[0038] Figure 1 A block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0039] Figure 1 The first device 100 and the second device 200 illustrated in can be replaced with various terms such as a terminal, a wireless device, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a mobile subscriber unit (MSU), a subscriber station (SS), an advanced mobile station (AMS), a wireless terminal (WT), or simply a user. Additionally, the first device 100 and the second device 200 include an access point (AP), a base station (BS), a fixed station, a Node B, a base transceiver system (BTS), a network. It can be replaced with various terms such as an artificial intelligence (AI) system, a roadside unit (RSU), a repeater, a router, a relay, and a gateway.

[0040] Figure 1 The devices 100 and 200 illustrated in Figure 1 can be referred to as a station (STA). For example, Figure 1 The devices 100 and 200 illustrated in Figure 1 can be referred to by various terms such as a transmitting device, a receiving device, a transmitting STA, and a receiving STA. For example, STAs 110 and 200 can perform an access point (AP) role or a non-AP role. That is, in the present disclosure, STAs 110 and 200 can perform AP and / or non-AP functions. When STAs 110 and 200 perform the AP function, they can be simply referred to as an AP, and when STAs 110 and 200 perform the non-AP function, they can be simply referred to as an STA. Additionally, in the present disclosure, an AP can also be indicated as an AP STA.

[0041] Referring to Figure 1 , the first device 100 and the second device 200 can transmit and receive radio signals through various wireless LAN technologies (e.g., the IEEE 802.11 series). The first device 100 and the second device 200 can include interfaces for a media access control (MAC) layer and a physical layer (PHY) compliant with the IEEE 802.11 standard.

[0042] Additionally, in addition to wireless LAN technologies, the first device 100 and the second device 200 can additionally support various communication standard (e.g., 3GPP LTE series, 5G NR series standards, etc.) technologies. Additionally, the devices of the present disclosure can be implemented in various devices such as a mobile phone, a vehicle, a personal computer, an augmented reality (AR) device, and a virtual reality (VR) device. Additionally, the STAs of the present specification can support various communication services such as a voice call, a video call, data communication, autonomous driving, machine type communication (MTC), machine-to-machine (M2M), device-to-device (D2D), and IoT (Internet of Things).

[0043] The 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. The processor 102 may control the memory 104 and / or the transceiver 106, and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. For example, after generating first information / signal by processing the information in the memory 104, the processor 102 may transmit a wireless signal including the first information / signal through the transceiver 106. Additionally, the processor 102 may receive a wireless signal including second information / signal through the transceiver 106, and then store the information obtained by signal processing of the second information / signal in the memory 104. The memory 104 may be connected to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may store software code including instructions for performing all or part of the processing controlled by the processor 102 or for performing the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. Here, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., IEEE 802.11 series). The transceiver 106 may be connected to the processor 102 and may transmit and / or receive wireless signals through one or more antennas 108. The transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be used with an RF (radio frequency) unit. In the present disclosure, a wireless device may mean a communication modem / circuit / chip.

[0044] The 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. The processor 202 may control the memory 204 and / or the transceiver 206, and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. For example, the processor 202 may generate third information / signals by processing the information in the memory 204, and then transmit wireless signals including the third information / signals through the transceiver 206. Additionally, the processor 202 may receive wireless signals including fourth information / signals through the transceiver 206, and then store the information obtained by signal processing of the fourth information / signals in the memory 204. The memory 204 may be connected to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may store software codes including instructions for performing all or part of the processing controlled by the processor 202 or for performing the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. Here, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement wireless LAN technologies (e.g., the IEEE 802.11 series). The transceiver 206 may be connected to the processor 202 and may transmit and / or receive wireless signals through one or more antennas 208. The transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be used with an RF unit. In the present disclosure, a device may mean a communication modem / circuit / chip.

[0045] Hereinafter, the hardware components of apparatuses 100 and 200 will be described in more detail. Without being limited thereto, one or more protocol layers may be implemented by one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as PHY and MAC). One or more processors 102 and 202 may generate one or more PDUs (Protocol Data Units) and / or one or more SDUs (Service Data Units) according to the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts disclosed in the present disclosure. One or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts disclosed in the present disclosure. One or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, suggestions, and / or methods disclosed in the present disclosure to provide them to one or more transceivers 106 and 206. One or more processors 102 and 202 may receive signals (e.g., baseband signals) from one or more transceivers 106 and 206 according to the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure, and obtain PDUs, SDUs, messages, control information, data, or information.

[0046] One or more processors 102 and 202 may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. One or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more ASICs (Application Specific Integrated Circuits), one or more DSPs (Digital Signal Processors), one or more DSPDs (Digital Signal Processor Devices), one or more PLDs (Programmable Logic Devices), or one or more FPGAs (Field Programmable Gate Arrays) may be included in one or more processors 102 and 202. The descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure may be implemented by using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. The firmware or software configured to execute the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure may be included in one or more processors 102 and 202, or may be stored in one or more memories 104 and 204 and driven by one or more processors 102 and 202. The descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure may be implemented by using firmware or software in the form of code, instructions, and / or instruction sets.

[0047] One or more memories 104, 204 may be connected to one or more processors 102, 202 and may store data, signals, messages, information, programs, code, instructions, and / or commands in various forms. One or more memories 104, 204 may be configured with ROM, RAM, EPROM, flash memory, hard disk drives, registers, cache memories, computer-readable storage media, and / or combinations thereof. One or more memories 104, 204 may be located inside and / or outside one or more processors 102, 202. Additionally, one or more memories 104, 204 may be connected to one or more processors 102, 202 through various techniques such as wired or wireless connections.

[0048] One or more transceivers 106, 206 may send user data, control information, wireless signals / channels, etc. mentioned in the methods and / or operation flowcharts, etc. of the present disclosure to one or more other devices. One or more transceivers 106, 206 may receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts, etc. included in the present disclosure from one or more other devices. For example, one or more transceivers 106, 206 may be connected to one or more processors 102, 202 and may send and receive wireless signals. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to send user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors 102, 202 may control one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers 106, 206 may be connected to one or more antennas 108, 208, and one or more transceivers 106, 206 may be configured to send and receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts, etc. included in the present disclosure through one or more antennas 108, 208. In the present disclosure, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106, 206 may convert the received wireless signals / channels, etc. from RF band signals into baseband signals to process the received user data, control information, wireless signals / channels, etc. by using one or more processors 102, 202. One or more transceivers 106, 206 may convert the user data, control information, wireless signals / channels, etc. processed by using one or more processors 102, 202 from baseband signals into RF band signals. Thus, one or more transceivers 106, 206 may include (analog) oscillators and / or filters.

[0049] For example, one of STAs 100 and 200 may perform the expected operations of an AP, and the other of STAs 100 and 200 may perform the expected operations of a non-AP STA. For example, Figure 1 the transceivers 106 and 206 may perform the sending and receiving operations of signals (e.g., packets or physical layer protocol data units (PPDUs) compliant with IEEE 802.11a / b / g / n / ac / ax / be / bn). Additionally, in the present disclosure, the operations of various STAs generating transmission / reception signals or pre-performing data processing or calculations on transmission / reception signals may be performed by Figure 1are executed by processors 102 and 202. For example, examples of operations for generating transmission / reception signals or performing data processing or calculations in advance for transmission / reception signals may include: 1) determining / acquiring / configuring / calculating / decoding / encoding bit information of fields (signals (SIG), short training fields (STF), long training fields (LTF), data, etc.) included in a PPDU; 2) determining / configuring / acquiring time resources or frequency resources (e.g., subcarrier resources) for fields (SIG, STF, LTF, data, etc.) included in a PPDU; 3) determining / configuring / acquiring a specific sequence (e.g., pilot sequence, STF / LTF sequence, additional sequence applied to SIG) for fields (SIG, STF, LTF, data, etc.) included in a PPDU operation; 4) power control operations and / or power saving operations applied to an STA; 5) operations related to determining / acquiring / configuring / calculating / decoding / encoding, etc. of an ACK signal. Additionally, in the following examples, various information (e.g., information related to fields / sub-fields / control fields / parameters / power, etc.) used by various STAs to determine / acquire / configure / calculate / decode / encode transmission signals and reception signals may be stored in Figure 1 memories 104 and 204.

[0050] Hereinafter, a downlink (DL) may refer to a link for communication from an AP STA to a non-AP STA, and DL PPDUs / packets / signals may be transmitted and received through 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. An uplink (UL) may refer to a link for communication from a non-AP STA to an AP STA, and UL PPDUs / packets / signals may be transmitted and received through 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.

[0051] Figure 2 is a diagram illustrating an exemplary structure of a wireless LAN system to which the present disclosure may be applied.

[0052] The structure of a wireless LAN system may be composed of multiple components. A wireless LAN that supports STA mobility transparent to an upper layer may be provided through the interaction of multiple components. A basic service set (BSS) corresponds to a basic building block of a wireless LAN. Figure 2 Exemplarily, it is shown that there are two BSSs (BSS1 and BSS2), and two STAs included as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). Figure 2The ellipse representing the BSS can also be understood as representing the coverage area where the STAs included in the corresponding BSS maintain communication. This area can be referred to as the Basic Service Area (BSA). When an STA moves outside the BSA, it cannot directly communicate with other STAs within the BSA.

[0053] If the DS shown in Figure 2 is not considered, the most basic type of BSS in a wireless LAN is the Independent BSS (IBSS). For example, an IBSS can have a minimum form that contains only two STAs. For example, assuming other components are omitted, BSS1 that contains only STA1 and STA2 or BSS2 that contains only STA3 and STA4 can respectively correspond to representative examples of an IBSS. This configuration is possible when STAs can directly communicate without an AP. Additionally, in this type of wireless LAN, it is not pre-configured but can be configured when a LAN is needed, and this can be referred to as an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. That is, in an IBSS, STAs are managed in a distributed manner. In an IBSS, all STAs can consist of mobile STAs and are not allowed to access the Distributed System (DS), thus forming a self-contained network.

[0054] The membership of STAs in a BSS can be dynamically changed by turning STAs on or off, entering or exiting the BSS area, etc. To become a member of a BSS, an STA can use synchronization processing to join the BSS. To access all services of the BSS infrastructure, an STA should be associated with the BSS. This association can be dynamically established and can include using the Distribution System Service (DSS).

[0055] The direct STA-to-STA distance in a wireless LAN may be limited by the PHY performance. In some cases, this distance limitation may be sufficient, but in some cases, communication between STAs at longer distances may be required. The Distributed System (DS) can be configured to support extended coverage.

[0056] DS means the structure for interconnecting BSSs. Specifically, as Figure 2As shown, the BSS can exist as an extended form of a network composed of multiple BSSs. The DS is a logical concept and can be specified by the characteristics of the distributed system medium (DSM). In this regard, the wireless medium (WM) and the DSM can be logically separated. Each logical medium is used for different purposes and is used by different components. These media are not limited to being the same, nor are they limited to being different. In this way, the flexibility of the wireless LAN structure (DS structure or other network structures) can be interpreted as multiple media being logically different. That is to say, the wireless LAN structure can be implemented in various ways, and the corresponding wireless LAN structure can be independently specified by the physical characteristics of each implementation.

[0057] The DS can support mobile devices by providing seamless integration of multiple BSSs and providing the logical services necessary for addressing the addresses to the destination. Additionally, the DS can also include a component called a portal, which is used as a bridge for the connection between the wireless LAN and other networks (e.g., IEEE 802.X).

[0058] The AP enables access to the DS via the WM for the associated non-AP STA and refers to an entity that also has the STA function. The data movement between the BSS and the DS can be performed by the AP. For example, Figure 2 STA2 and STA3 shown in have the function of the STA and provide the function of allowing the associated non-AP STAs (STA1 and STA4) to access the DS. Additionally, since all APs basically correspond to STAs, all APs are addressable entities. The address used by the AP for communication on the WM is not necessarily the same as the address used by the AP for communication on the DSM. The BSS composed of an AP and one or more STAs can be called an infrastructure BSS.

[0059] Data sent from one of the STAs associated with the AP to the STA address of the corresponding AP can always be received at the uncontrolled port and can be processed by the IEEE 802.1X port access entity. Additionally, when the controlled port is authenticated, the transmitted data (or frame) can be delivered to the DS.

[0060] In addition to the above DS structure, the extended service set (ESS) can also be configured to provide wide coverage.

[0061] An ESS refers to a network consisting of a DS and BSSs, with arbitrary size and complexity. An ESS can correspond to a set of BSSs connected to a DS. However, an ESS does not include the DS. The ESS network is characterized by being regarded as an IBSS in the logical link control (LLC) layer. The STAs included in an ESS can communicate with each other, and a mobile STA can move transparently for the LLC from one BSS to another BSS (within the same ESS). The APs included in an ESS can have the same service set identifier (SSID). The SSID is distinguished from the BSSID which is the identifier of a BSS.

[0062] The wireless LAN system does not assume anything about the relative physical positions of BSSs, and all of the following forms are possible. BSSs can partially overlap, which is a form commonly used to provide continuous coverage. Additionally, BSSs can be physically unconnected, and logically, there is no limit on the distance between BSSs. Additionally, BSSs can be physically located at the same position, which can be used to provide redundancy. Additionally, one (or more than one) IBSS or ESS network can physically exist in the same space as one (or more than one) ESS network. This can correspond to forms of ESS networks when an ad-hoc network operates at the location where an ESS network exists, when physically overlapping wireless networks are configured by different organizations, or when two or more different access and security policies are required at the same location.

[0063] Figure 3 is a diagram for illustrating the link establishment process to which the present disclosure can be applied.

[0064] In order for an STA to establish a link with respect to a network and send / receive data, it first discovers the network, performs authentication, establishes an association, and needs to perform an authentication process for security. The link establishment process can also be referred to as a session initiation process or a session establishment process. Additionally, the processes of discovery, authentication, association, and security establishment in the link establishment process can be collectively referred to as an association process.

[0065] In step S310, the STA can perform a network discovery operation. The network discovery operation can include a scanning operation of the STA. That is, in order for the STA to access a network, it needs to find a network that it can participate in. The STA should identify compatible networks before participating in a wireless network, and the process of identifying the networks existing in a specific area is called scanning.

[0066] Scanning schemes include active scanning and passive scanning. Figure 3A network discovery operation including an active scanning process is exemplarily illustrated. In active scanning, the STA performing the scan sends a probe request frame to discover which APs exist around it while moving across channels and waits for a response thereto. The responder sends a probe response frame as a response to the probe request frame to the STA that has sent the probe request frame. Here, the responder can be the STA that last sent a beacon frame in the BSS of the channel being scanned. In a BSS, since the AP sends a beacon frame, the AP becomes the responder, and in an IBSS, the STAs in the IBSS rotate to send beacon frames, so the responder is not constant. For example, the STA that sends a probe request frame on channel 1 and receives a probe response frame on channel 1 can store the BSS-related information included in the received probe response frame, and can move to the next channel (e.g., channel 2), and perform the scan in the same way (i.e., send and receive probe requests / responses on channel 2).

[0067] Although not shown in Figure 3 it, the scan operation can be performed in a passive scanning manner. In passive scanning, the STA performing the scan waits for beacon frames while moving across channels. A beacon frame is one of the management frames defined in IEEE 802.11 and is periodically sent to notify the existence of a wireless network and to allow the STA performing the scan to find the wireless network and participate in the wireless network. In a BSS, the AP is used to periodically send beacon frames, and in an IBSS, the STAs within the IBSS rotate to send beacon frames. When the STA performing the scan receives a beacon frame, the STA stores the information of the BSS included in the beacon frame, and while moving to another channel, records the beacon frame information in each channel. The STA that receives a beacon frame can store the BSS-related information included in the received beacon frame, move to the next channel, and perform the scan in the next channel in the same way. Comparing active scanning with passive scanning, the advantage of active scanning is that it has less latency and less power consumption than passive scanning.

[0068] After the STA discovers the network, the authentication process can be performed in step S320. To clearly distinguish it from the security establishment operation in step S340 to be described later, this authentication process can be referred to as the first authentication process.

[0069] The authentication process includes the following process: The STA sends an authentication request frame to the AP, and in response thereto, the AP sends an authentication response frame to the STA. The authentication frame for authentication request / response corresponds to a management frame.

[0070] The authentication frame includes an authentication algorithm number, an authentication transaction serial number, a status code, a challenge text, a Robust Security Network (RSN), a finite cyclic group, etc. This corresponds to some examples of information that can be included in the authentication request / response frame, and can be replaced with other information, or additional information can also be included.

[0071] The STA can send an authentication request frame to the AP. The AP can determine whether to allow the 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 through an authentication response frame.

[0072] After the STA is successfully authenticated, the association process can be performed in step S330. The association process includes the following processes: The STA sends an association request frame to the AP, and in response, the AP sends an association response frame to the STA.

[0073] For example, the association request frame can include information related to various capabilities, a beacon listening interval, a Service Set Identifier (SSID), supported rates, supported channels, RSN, a mobility domain, supported operation classes, a Traffic Indication Map Broadcast Request (TIM broadcast request), interoperability service capabilities, etc. For example, the association response frame can include information related to various capabilities, a status code, an Association ID (AID), supported rates, an Enhanced Distributed Channel Access (EDCA) parameter set, a Received Channel Power Indicator (RCPI), a Received Signal-to-Noise Ratio Indicator (RSNI), a mobility domain, a timeout interval (e.g., an association recovery time), overlapping BSS scan parameters, a TIM broadcast response, Quality of Service (QoS) mapping, etc. This corresponds to some examples of information that can be included in the association request / response frame, and can be replaced with other information, or additional information can also be included.

[0074] After the STA is successfully associated with the network, the security establishment process can be performed in step S340. The security establishment process in step S340 can be referred to as an authentication process through Robust Security Network Association (RSNA) request / response. The authentication process in step S320 is referred to as the first authentication process, and the security establishment process in step S340 can also simply be referred to as an authentication process.

[0075] The security establishment process in step S340 can, for example, include a process of establishing a private key using the four-way handshake through Extensible Authentication Protocol over LAN (EAPOL) frames. Additionally, the security establishment process can be performed according to a security scheme not defined in the IEEE 802.11 standard.

[0076] Figure 4 It is a diagram for explaining the backoff process to which the present disclosure can be applied.

[0077] In a wireless LAN system, the basic access mechanism of the Media Access Control (MAC) is the Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) mechanism. The CSMA / CA mechanism is also known as the Distributed Coordination Function (DCF) of the IEEE 802.11 MAC and basically adopts a "listen before talk" access mechanism. According to this type of access mechanism, before starting transmission, the AP and / or STA can perform a Clear Channel Assessment (CCA) of sensing the radio channel or medium during a predetermined time interval (e.g., the DCF Interframe Space (DIFS)). As a result of the sensing, if it is determined that the medium is idle, frame transmission is started through the corresponding medium. On the other hand, if the medium is detected to be occupied or busy, the corresponding AP and / or STA does not start its own transmission and can set a delay period for medium access (e.g., a random backoff period) and attempt frame transmission after waiting. By applying the random backoff period, since it is expected that multiple STAs will attempt frame transmission after waiting for different periods of time, collisions can be minimized.

[0078] In addition, the IEEE 802.11 MAC protocol provides a Hybrid Coordination Function (HCF). The HCF is based on the DCF and the Point Coordination Function (PCF). The PCF is a polling-based synchronous access method and refers to the method in which all receiving APs and / or STAs are periodically polled to receive data frames. In addition, the HCF has an Enhanced Distributed Channel Access (EDCA) and a HCF Controlled Channel Access (HCCA). The EDCA is a contention-based access method that provides data frames to multiple users in a directed manner, and the HCCA uses a contention-free channel access method that utilizes a polling mechanism. In addition, the HCF includes a medium access mechanism for improving the Quality of Service (QoS) of the wireless LAN and can send QoS data during a Contention Period (CP) and a Contention-Free Period (CFP).

[0079] Refer to Figure 4, operations based on a random backoff period will be described. When the occupied / busy medium becomes idle, multiple STAs can attempt to send data (or frames). As a method to minimize collisions, each of the STAs can separately select a random backoff count and attempt to send after waiting for the corresponding slot time. The random backoff count has a pseudo-random integer value and can be determined as one of the values that vary from 0 to the value of CW. Here, CW is the contention window parameter value. The CW parameter is given the initial value of CWmin, but can take a value twice as large in the case of a transmission failure (e.g., when an ACK for the transmitted frame is not received). When the CW parameter value reaches CWmax, data transmission can be attempted while maintaining the CWmax value until the data transmission is successful, and when the data transmission is successful, the CWmin value is reset. The values of CW, CWmin, and CWmax are preferably set to 2n - 1 (n = 0, 1, 2,...).

[0080] When the random backoff process starts, the STA continuously monitors the medium during the countdown of the backoff slot according to the determined backoff count value. When monitoring the medium for occupancy, it stops the countdown and waits, and when the medium becomes idle, it resumes the remaining part of the countdown.

[0081] In Figure 4 the example, when the packet to be sent arrives at the MAC of STA 3, STA3 can immediately send a frame after confirming that the medium has been idle for up to DIFS. The remaining STAs monitor and wait for the medium to be occupied / busy. At the same time, the data to be sent can also occur in each of STA1, STA2, and STA5, and when the medium is monitored as idle, each STA waits for up to DIFS and then can perform the countdown of the backoff slot according to the random backoff count value selected by each STA. Assume that STA2 selects the minimum backoff count value and STA1 selects the maximum backoff count value. That is, an example is shown where the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1 when STA2 finishes the backoff count and starts frame transmission. STA1 and STA5 temporarily stop the countdown and wait while STA2 occupies the medium. When the occupancy of STA2 ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and resume the stopped backoff count. That is, frame transmission can start after counting down the remaining backoff slots for the remaining backoff time. Since the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1, STA5 starts frame transmission. When STA2 occupies the medium, the data to be sent can also occur in STA4. From the perspective of STA4, when the medium becomes idle, STA4 can wait for DIFS and then can perform the countdown according to the random backoff count value selected by STA4 and start sending a frame. Figure 4The example shows a situation where the remaining backoff time of STA5 accidentally conflicts with the random backoff counter value of STA4. In this case, a conflict may occur between STA4 and STA5. When a conflict occurs, neither STA4 nor STA5 receives an ACK, so the data transmission fails. In this case, STA4 and STA5 can double the CW value, select a random backoff counter value, and perform a countdown. When the medium is occupied due to the transmissions of STA4 and STA5, STA1 waits. When the medium becomes idle, STA1 waits for DIFS, and then starts frame transmission after the remaining backoff time has passed.

[0082] As in Figure 4 the example, the data frame is a frame for transmitting data forwarded to a higher layer, and can be transmitted after a backoff that is performed after DIFS has elapsed since the medium became idle. Additionally, the management frame is a frame for exchanging management information that is not forwarded to a higher layer, and is transmitted after a backoff that is performed after an IFS such as DIFS or Point Coordination Function IFS (PIFS). As subtype frames of the management frame, there are beacons, association request / response, re-association request / response, probe request / response, authentication request / response, etc. The control frame is a frame for controlling access to the medium. As subtype frames of the control frame, there are Request to Send (RTS), Clear to Send (CTS), Acknowledgment (ACK), Power Save Poll (PS-Poll), Block Ack (BlockAck), Block ACK Request (BlockACKReq), Null Data Packet Announcement (NDP Announcement), and Trigger, etc. If the control frame is not a response frame to the previous frame, it is transmitted after a backoff that is performed after DIFS has elapsed, and if it is a response frame to the previous frame, it is transmitted without performing a backoff after Short IFS (SIFS) has elapsed. The type and subtype of a frame can be identified by the type field and subtype field in the Frame Control (FC) field.

[0083] The Quality of Service (QoS) STA can perform a backoff that is performed after the Arbitration IFS (AIFS) for the access category (AC) to which the frame belongs (i.e., AIFS (where i is a value determined by the AC)), and then can transmit the frame. Here, the frames for which AIFS can be used can be data frames, management frames, or control frames other than response frames.

[0084] Figure 5 is a diagram for explaining the CSMA / CA-based frame transmission operation to which the present disclosure can be applied.

[0085] As described above, in addition to the physical carrier sensing by the STA directly sensing the medium, the CSMA / CA mechanism also includes virtual carrier sensing. Virtual carrier sensing aims to compensate for problems such as the hidden node problem that may occur in medium access. For virtual carrier sensing, the MAC of the STA can use the 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 the STA that currently uses or has the right to use the medium. Therefore, the value set as the NAV corresponds to the period during which the STA that transmits the frame plans to use the medium, and during the corresponding period, the STA that receives the NAV value is prohibited from accessing the medium. For example, the NAV can be configured based on the value of the "Duration" field in the MAC header of the frame.

[0086] In Figure 5 the example, it is assumed that STA1 aims to send data to STA2, and STA3 is in a position where it can overhear some or all of the frames transmitted and received between STA1 and STA2.

[0087] To reduce the possibility of transmission conflicts among multiple STAs in the CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames can be applied. In Figure 5 the example, when the transmission of STA1 is being executed, as a result of the carrier sensing of STA3, it can be determined that the medium is in an idle state. That is, STA1 can correspond to a hidden node with respect to STA3. Alternatively, in Figure 5 the example, it can be determined that when the transmission of STA2 is being executed, the carrier sensing result of STA3 indicates that the medium is in an idle state. That is, STA2 can correspond to a hidden node with respect to STA3. By exchanging RTS / CTS frames before the data transmission and reception between STA1 and STA2, STAs outside the transmission range of either STA1 or STA2 or STAs outside the carrier sensing range of the transmission from STA1 or STA3 can refrain from attempting to occupy the channel during the data transmission and reception between STA1 and STA2.

[0088] Specifically, STA1 can determine whether the channel is being used through carrier sensing. In terms of physical carrier sensing, STA1 can determine the occupied or idle state of the channel based on the energy level or signal correlation detected in the channel. Additionally, in terms of virtual carrier sensing, STA1 can use the Network Allocation Vector (NAV) timer to determine the channel occupancy state.

[0089] When the channel is in an idle state during DIFS, STA1 can send an RTS frame to STA2 after performing backoff. When STA2 receives the RTS frame, STA2 can send a CTS frame to STA1 as a response to the RTS frame after SIFS.

[0090] If STA3 cannot overhear the CTS frame from STA2 but can overhear the RTS frame from STA1, STA3 can use the duration information included in the RTS frame to set the NAV timer for the transmission period of the frames continuously sent thereafter (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame). Alternatively, if STA3 can overhear the CTS frame from STA2, even though STA3 cannot overhear the RTS frame from STA1, STA3 can also use the duration information included in the CTS frame to set the NAV timer for the transmission period of the frames continuously sent thereafter (e.g., SIFS + data frame + SIFS + ACK frame). That is, if STA3 can overhear one or more of the RTS frame or the CTS frame from one or more of STA1 or STA2, STA3 can set the NAV accordingly. When STA3 receives a new frame before the expiration of the NAV timer, STA3 can use the duration information included in the new frame to update the NAV timer. STA3 does not attempt channel access until the NAV timer expires.

[0091] When STA1 receives the CTS frame from STA2, STA1 can send a data frame to STA2 after SIFS from the time point when the reception of the CTS frame is completed. When STA2 successfully receives the data frame, STA2 can send an ACK frame to STA1 after SIFS as a response to the data frame. When the NAV timer expires, STA3 can determine whether the channel is being used through carrier sensing. When STA3 determines during the DIFS period after the expiration of the NAV timer that the channel is not being used by other terminals, STA3 can attempt channel access after the contention window (CW) according to random backoff has elapsed.

[0092] Figure 6 It is a diagram for illustrating an example of the frame structure used in a WLAN system to which the present disclosure can be applied.

[0093] With instructions or primitives (meaning a set of instructions or parameters) from the MAC layer, the PHY layer can prepare the MAC PDU (MPDU) to be transmitted. For example, when receiving a command from the MAC layer to request the start of transmission by the PHY layer, the PHY layer switches to the transmission mode, configures the information (e.g., data) provided by the MAC layer in the form of a frame, and transmits it. Additionally, when the PHY layer detects the valid preamble of the received frame, the PHY layer monitors the header of the preamble and sends a command to the MAC layer notifying the start of reception by the PHY layer.

[0094] In this way, information transmission / reception in a wireless LAN system is performed in the form of frames, and for this purpose, the PHY layer protocol data unit (PPDU) format is defined.

[0095] The basic PPDU may include a Short Training Field (STF), a Long Training Field (LTF), a Signal (SIG) field, and a Data field. The most basic PPDU format (e.g., the non-HT (High Throughput) shown in Figure 7 may consist only of a Legacy-STF (L-STF), a Legacy-LTF (L-LTF), a Legacy-SIG (L-SIG) field, and a Data field. Additionally, depending on the type of PPDU format (e.g., HT Mixed format PPDU, HT Greenfield format PPDU, VHT (Very High Throughput) PPDU, etc.), additional (or different types of) RL-SIG, U-SIG, non-legacy SIG fields, non-legacy STF, non-legacy LTF (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) etc. may be included between the L-SIG field and the Data field.

[0096] The STF is a signal for signal detection, automatic gain control (AGC), diversity selection, precise time synchronization, etc., 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.

[0097] The SIG field may include various information related to PPDU transmission and reception. For example, the L-SIG field consists of 24 bits, and the L-SIG field may include a 4-bit Rate field, a 1-bit Reserved bit, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field. The RATE field may include information about the modulation and coding rate of the 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 can be determined based on the type of PPDU. For example, for non-HT, HT, VHT, or EHT PPDU, the value of the Length field can be determined to be a multiple of 3. For example, for HE PPDU, the value of the Length field can be determined to be a multiple of 3 + 1 or 3 + 2.

[0098] The data field may include a SERVICE field, a Physical Layer Service Data Unit (PSDU), and PPDU tail bits, and may also include padding bits if necessary. Some bits of the SERVICE field may be used for synchronization of the descrambler at the receiving end. The PSDU corresponds to the MAC PDU defined in the MAC layer and may include data generated / used in the upper layer. The PPDU tail bits may be used to return the encoder to the 0 state. The padding bits may be used to adjust the length of the data field in predetermined units.

[0099] The MAC PDU is defined according to various MAC frame formats, and the basic MAC frame consists of a MAC header, a frame body, and a Frame Check Sequence (FCS). The MAC frame may be composed of MAC PDUs and transmitted / received through the PSDU of the data part in the PPDU format.

[0100] The MAC header includes a Frame Control field, a Duration / ID field, an Address field, etc. The Frame Control field may include control information required for frame transmission / reception. The Duration / ID field may be set to the time for transmitting the corresponding frame, etc. For details of the Sequence Control, QoS Control, and HT Control sub-fields of the MAC header, refer to the IEEE 802.11 standard document.

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

[0102] Figure 7 is a diagram illustrating an example of the PPDU defined in the IEEE 802.11 standard to which the present disclosure can be applied.

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

[0104] Compared with the basic PPDU format, the HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT fields. Figure 7The HT PPDU format shown in (b) of can be referred to as the HT mixed format. Additionally, an HT greenfield format PPDU can be defined, and this corresponds to a format (not shown) consisting of an HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a data field, excluding the L-STF, L-LTF, and L-SIG.

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

[0106] Compared to the basic PPDU format, an example of the HE PPDU format (IEEE 802.11ax) additionally includes a repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF, and packet extension (PE) fields (as Figure 7 shown in (d) of . Some fields can be excluded, or their lengths can vary according to the detailed example of the HE PPDU format. For example, the HE-SIG-B field is included in the HE PPDU format for multi-user (MU), and the HE-SIG-B is not included in the HE PPDU format for single-user (SU). Additionally, the HE trigger-based (TB) PPDU format does not include the HE-SIG-B, and the length of the HE-STF field can vary up to 8 μs. The extended range (HE ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field can vary up to 16 μs. For example, the RL-SIG can be configured to be the same as the L-SIG. Based on the presence of the RL-SIG, the receiving STA can know that the received PPDU is an HE PPDU or an EHT PPDU, which will be described later.

[0107] The EHT PPDU format can include Figure 7 the EHT MU (multi-user) in (e) of and Figure 7 the EHT TB (trigger-based) PPDU in (f) of . The EHT PPDU format is similar to the HE PPDU format in including an RL-SIG following the L-SIG, but can include a U (universal)-SIG, EHT-SIG, EHT-STF, and EHT-LTF following the RL-SIG.

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

[0109] Compared with the EHT MU PPDU, Figure 7 The EHT TB PPDU in (f) omits the EHT-SIG. A STA that receives a trigger for UL MU transmission (e.g., a trigger frame or a triggered response schedule (TRS)) can perform UL transmission based on the EHT TB PPDU 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 a legacy STA can attempt to demodulate and decode, and can be mapped based on the determined subcarrier frequency spacing (e.g., 312.5 kHz). These can be referred to as pre-EHT modulation fields. Next, the EHT-STF, EHT-LTF, data, and PE fields can be encoded and modulated to be demodulated and decoded by a STA that successfully decodes a non-legacy SIG (e.g., U-SIG and / or EHT-SIG) and obtains the information included in this field, and can be mapped based on the determined subcarrier frequency spacing (e.g., 78.125 kHz). These can be referred to as EHT modulation fields.

[0111] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields can be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, data, and PE fields can be referred to as HE modulation fields. Additionally, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be referred to as non-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and data fields can be referred to as VHT modulation fields.

[0112] Included in Figure 7The U-SIG in the EHT PPDU format 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 symbol of the U-SIG can be used to transmit 26 bits of information. For example, each symbol of the U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0113] The U-SIG can be constructed in units of 20 MHz. For example, if an 80 MHz PPDU is constructed, the U-SIG can be replicated. That is, the same 4 U-SIGs can be included in the 80 MHz PPDU. A PPDU with a bandwidth exceeding 80 MHz can include different U-SIGs.

[0114] For example, A uncoded bits can be transmitted through the U-SIG. The first symbol of the U-SIG (e.g., U-SIG-1 symbol) can transmit the first X bits of information out of a total of A bits of information, and the second symbol of the U-SIG (e.g., U-SIG-2 symbol) can transmit the remaining Y bits of information out of a total of A bits of information. The A bits of information (e.g., 52 uncoded bits) can include a CRC field (e.g., a 4-bit long field) and a tail field (e.g., a 6-bit long field). For example, the tail field can be used to terminate the trellis structure of the convolutional decoder and can be set to 0.

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

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

[0117] For example, the version-independent bits of the U-SIG may include a 3-bit Physical Layer Version Identifier (PHY Version Identifier), and this information may indicate the PHY version of the transmitted / received PPDU (e.g., EHT, UHR, etc.). The version-independent bits of the U-SIG may include a 1-bit UL / DL flag field. The first value of the 1-bit UL / DL flag field is associated with UL communication, and the second value of the UL / DL flag field is associated with DL communication. The version-independent bits of the U-SIG may include information about the length of the Transmit Opportunity (TXOP) and information about the BSS Color ID.

[0118] For example, the version-dependent bits of the U-SIG may include information that directly or indirectly indicates the type of the PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).

[0119] The information required for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may also include information about the bandwidth, information about the MCS technique applied to non-traditional SIGs (e.g., EHT-SIG or UHR-SIG, etc.), information indicating whether the DCM (Dual Carrier Modulation) technique (e.g., a technique for achieving an effect similar to frequency diversity by reusing the same signal on two subcarriers) is applied to non-traditional SIGs, information about the number of symbols for non-traditional SIGs, information about whether non-traditional SIGs are generated across the entire frequency band.

[0120] Some of the information required for PPDU transmission and reception may be included in the U-SIG and / or non-traditional SIGs (e.g., EHT-SIG or UHR-SIG, etc.). For example, information about the type of non-traditional LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information about the length of non-traditional LTF and the CP (Cyclic Prefix) length, information about the GI (Guard Interval) applicable to non-traditional LTF, information about the preamble puncturing applicable to the PPDU, information about the Resource Unit (RU) allocation, etc. may be included only in the U-SIG, included only in non-traditional SIGs, or may be indicated by a combination of the information included in the U-SIG and the information included in non-traditional SIGs.

[0121] Preamble puncturing may represent the transmission of the following PPDU, where there is no signal in one or more frequency units among the bandwidth of the PPDU. For example, the size of the frequency unit (or the resolution of the preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to a PPDU bandwidth of a predetermined size or larger.

[0122] In Figure 7In an example, non - traditional SIGs such as HE - SIG - B and EHT - SIG can include control information for receiving STAs. The non - traditional SIG can be sent on at least one symbol, and one symbol can have a length of 4 μs. Information about the number of symbols for EHT - SIG can be included in a previous SIG (e.g., HE - SIG - A, U - SIG, etc.).

[0123] Non - traditional SIGs such as HE - SIG - B and EHT - SIG can include a common field and user - specific fields. The common field and user - specific fields can be encoded separately.

[0124] In some cases, the common field can be omitted. For example, in a compressed mode that does not apply OFDMA (Orthogonal Frequency Division Multiple Access), the common field can be omitted, and multiple STAs can receive a PPDU (e.g., the data field of the PPDU) through the same frequency band. In a non - compressed mode that applies OFDMA, multiple users can receive a PPDU (e.g., the data field of the PPDU) through different frequency bands.

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

[0126] The common field can include CRC bits and tail bits. The length of the CRC bits can be determined to be 4 bits, and the length of the tail bits can be determined to be 6 bits and set to 000000. The common field can include RU allocation information. The RU allocation information can include information about the positions of the RUs assigned to multiple users (i.e., multiple receiving STAs).

[0127] An RU can include multiple sub - carriers (or tones). When sending signals to multiple STAs based on OFDMA technology, RUs can be used. Additionally, even when sending signals to one STA, RUs can be defined. Resources can be allocated for non - traditional STF, non - traditional LTF, and data fields in units of RUs.

[0128] The RU of an applicable size can be defined according to the PPDU bandwidth. 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 layouts of the HE PPDU and the EHT PPDU can be different. The applicable RU size, the number and position of RUs, the DC (direct current) subcarrier position and number, the null subcarrier position and number, the guard subcarrier position and number, etc. for each PPDU bandwidth can be referred to as a tone plan. For example, the tone plan for high bandwidth 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, 2×996-tone RUs, 3×996-tone RUs, etc. An MRU (multi-RU) is different from multiple individual RUs and corresponds to a set of subcarriers composed of multiple 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, 2×996 + 484 tones, 3×996 tones, or 3×996 + 484 tones. Additionally, the multiple RUs constituting an MRU can be continuous or non-continuous in the frequency domain.

[0130] The specific size of an RU can be reduced or extended. Therefore, the specific size (i.e., the number of corresponding tones) of each RU in the present disclosure is illustrative rather than restrictive. Additionally, in the present disclosure, within a predetermined bandwidth (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz...), the number of RUs can vary according to the RU size.

[0131] Figure 7 The name of each field in the PPDU format is exemplary, and the scope of the present disclosure is not limited by these names. Additionally, the examples of the present disclosure can be applied to Figure 7 the PPDU format shown in Figure 7 and new PPDU formats that exclude some fields and / or add some fields based on the

[0132] Multi-link operation

[0133] The multi-link (ML) operation supported by the STA according to the present disclosure is described below.

[0134] The STA (AP STA and / or non-AP STA) 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) in the frequency bands in which the STA operates (e.g., 2.4 GHz band, 5 GHz band, 6 GHz band, etc.). The multiple links for ML communication may be configured in various ways. For example, the multiple links supported by one 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 a predetermined size (e.g., channel, sub-channel, RU, etc.). Furthermore, some or all of the multiple links may be frequency units of the same size or may be frequency units of different sizes.

[0135] When a STA supports multiple links, the transmit and receive devices that support each link may operate as one logical STA. That is, an MLD refers to a device that has one or more attached STAs as logical entities and a single MAC service access point (SAP) for one MAC data service and logical link control (LLC). A non-AP MLD refers to an MLD in which each STA attached to the MLD is a non-AP STA. A multi-radio non-AP MLD refers to a non-AP MLD that supports receiving or exchanging frames on more than one link at a time. An AP MLD refers to an MLD in which each STA attached to the MLD is an AP STA.

[0136] Multi-link operation (MLO) may enable a non-AP MLD to discover an AP MLD, authenticate the AP MLD, associate with the AP MLD, and establish multiple links with the AP MLD. Based on the support capabilities exchanged during the association process, each link may enable channel access and frame exchange between the non-AP MLD and the AP MLD. The STAs attached to the MLD may select and manage their capabilities and operating parameters independently of other STAs attached to the same MLD.

[0137] During the multi-link establishment process, the AP MLD and / or non-AP MLD can send and receive information related to the links that the MLD can support. The link-related information can include at least one of the following items: information on whether the MLD supports simultaneous transmit and receive (STR) operations or non-simultaneous transmit and receive (NSTR) operations (which cannot support simultaneous transmit and receive on multiple links), information on the number / upper limit of UL / DL links, information on the location / bandwidth / resources of the UL / DL links, information on the frame type (e.g., management, control, data, etc.) available or preferred in at least one UL / DL link, information on the ACK policy available or preferred in at least one UL / DL link, or information on the traffic identifier (TID) available in at least one UL / DL link.

[0138] The AP MLD (e.g., NSTR mobile AP MLD) can configure one of the multiple links as the primary link. The AP MLD can perform beacon frames, probe response frames, and group-addressed data frames only on the primary link. The remaining other links among the multiple links can be referred to as non-primary links. The AP MLD operating on a non-primary link can operate not to send beacon frames or probe response frames. In addition, the non-AP MLD can perform frame exchanges only on the primary link during authentication, (re)association, and the four-way handshake.

[0139] If at least one traffic identifier (TID) is mapped to an established link through the multi-link establishment process, the link is defined as enabled, and if no TID is mapped to the established link, the link can be defined as disabled. Unless admission control is used, the TID should always be mapped to at least one established link. By default, the TID is mapped to all established links so that all established links can be enabled.

[0140] When the link is enabled, the link can be used for frame exchange, depending on the power state of the non-AP STA operating on the link. Only the MSDU or A-MSDU with a TID mapped to the enabled link can be sent on the link. Management frames and control frames can be sent only on the enabled link.

[0141] When the link is disabled, the link cannot be used for frame exchange, including management frames for both DL and UL.

[0142] During the multi-link establishment process, the enable / disable of each link can be indicated through the TID-to-link mapping. The TID-to-link mapping can be performed in the default mapping mode or / and the negotiated mapping mode.

[0143] One of the STAs belonging to the MLD may provide information for one or more links other than the link where the STA is located for multi-link discovery (e.g., obtaining information on multiple links including the corresponding link on one link) or multi-link establishment (e.g., simultaneously associating multiple links by exchanging association request / response frames on one link).

[0144] Figure 8 FIG. is a schematic diagram showing an exemplary relationship between multiple BSSID sets and multi-link devices to which the present disclosure can be applied.

[0145] Multi-BSSID operation may include a single physical access point (AP) operating on a single channel creating multiple virtual APs. In the following description, multi-BSSID may also be referred to as MBSSID.

[0146] The MBSSID set may include one or more non-transmitting BSSIDs and may define one transmitting BSSID.

[0147] In Figure 8 the example, x, y, p, q, r, a, b correspond to example values of BSSIDs, [T] represents the transmitting BSSID (or TxBSSID), and the BSSIDs not indicated by [T] represent non-transmitting BSSIDs (or non-Tx BSSIDs).

[0148] In Figure 8 the example, when considering both MBSSID operation and ML operation, the BSSIDs within one MBSSID set may belong to the MLD, and each of the multiple links belonging to one MLD may correspond to one channel (or the BSSID operating on the corresponding channel). Different MLDs may operate on multiple links on the same or different channels. For example, Link 0 (L0), Link 1 (L1), and Link 2 (L2) of MLD1 may be set on CH1, CH2, and CH3 respectively. For example, L0 and L1 of MLD2 may be set on CH2 and CH3 respectively. For example, L0 and L1 of MLD3 may be set on CH1 and CH2 respectively. BSSID-c may not belong to the MLD.

[0149] In this regard, the APs belonging to one MBSSID belong to different ESSs, and the APs belonging to one AP MLD belong to the same ESS. That is, the APs belonging to the MBSSID set cannot belong to the same AP MLD.

[0150] Multi-AP operation mode

[0151] Multi-AP operation may correspond to a scheme in which one or more APs send and receive information to / from one or more STAs.

[0152] In the case of a conventional single transmission (S-Tx) method, that is, a method in which a BSS AP transmits to a BSS STA, when the AP performs transmission and reception with a user (e.g., STA) at the cell edge, due to interference from an adjacent AP, there may be a problem of reduced performance.

[0153] In contrast, in the case of multi-AP technology, performance can be improved by methods such as reducing inter-symbol interference (ISI) through cooperation with neighbor APs or through joint transmission. In other words, in a multi-AP scheme, information is shared between APs and cooperation between APs is possible.

[0154] Figure 9 It is a schematic diagram showing an example of a multi-AP scheme to which the present disclosure can be applied.

[0155] Referring to Figure 9 As an example of a multi-AP scheme, Figure 9 (a) of Figure 9 (b) of Figure 9 (c) of Figure 9 (d) of

[0156] For example, as a multi-AP scheme, a coordinated TDMA (C-TDMA) scheme in which the allocation between APs is divided along the time axis, a C-OFDMA scheme divided along the frequency axis, or a coordinated spatial reuse (C-SR) scheme using spatial reuse can be considered. As an example, referring to Figure 9 (a) of

[0157] Additionally or alternatively, as a multi-AP scheme, a CBF scheme or a coordinated nulling (CN) scheme (which nulls the interference affecting neighbors and transmits) can be considered, and an AP selection scheme (which configures / defines an AP with better channel conditions among neighbor APs (i.e., adjacent APs) to perform transmission) can also be considered. For example, in the Figure 9 (c) of

[0158] Additionally or alternatively, as a multi-AP scheme, a J-Tx scheme (e.g., joint beamforming, joint MU-MIMO) can be considered, in which multiple APs cooperate to perform simultaneous transmission or reception. Figure 9 (d) of

[0159] In the above multi-AP solution, the multi-AP environment can consist of a master AP, slave APs, and STAs. In this regard, the master AP can be referred to as a shared AP, and the slave APs can be referred to as shared APs.

[0160] Here, the master AP can play a role in initiating and controlling multi-AP operations, where multi-AP operations correspond to the technology of multiple APs for sending and receiving. Additionally, the master AP can group the slave APs and manage the links with the slave APs so that information can be shared among the slave APs. Additionally, the master AP can manage information about the BSS configured by the slave APs and information about the STAs associated with the corresponding BSS.

[0161] By establishing an association with the master AP, the slave APs can share control information, management information, data services, etc. with each other. Additionally, the slave APs can basically perform the same functions as the APs in a conventional wireless LAN system that can establish a BSS.

[0162] As in a conventional wireless LAN system, an STA can construct a BSS by associating with an AP (i.e., the master AP or a slave AP).

[0163] In the above multi-AP environment, the master AP and the slave APs can be capable of directly sending and receiving between each other. Additionally or alternatively, the master AP and the STA may not be capable of directly sending and receiving between each other. Additionally or alternatively, (a slave AP associated with the STA) and the STA can be capable of directly sending and receiving between each other. Additionally or alternatively, one of the slave APs can be the master AP.

[0164] Method for supporting multiple associations for multiple APs

[0165] Since all APs have a limited communication range, it is impossible to support wireless LAN sending and receiving (e.g., Wi-Fi sending and receiving) with only one AP in a wide space.

[0166] To solve this problem, multiple APs can be deployed, and a method can be applied where an STA (e.g., a non-AP STA) moves away from the AP with which it is associated and then moves to another AP to perform communication.

[0167] This method can be referred to as roaming. At this time, when the STA moves to another AP and performs communication, roaming without any interruption (from the perspective of the user, i.e., the STA) can be referred to as seamless roaming.

[0168] Figure 10 A schematic diagram for explaining the roaming to which the present disclosure can be applied is illustrated.

[0169] Refer to Figure 10, the ranges supported by the first AP and the second AP can be indicated by circular regions respectively.

[0170] Although Figure 10 only two APs are illustrated in [reference], the method proposed in the present disclosure is not limited thereto, and even if a larger number of APs are deployed, the method proposed in the present disclosure can be applied.

[0171] The STA can be configured to perform roaming when moving from the range supported by the first AP to the range supported by the second AP.

[0172] However, the roaming method in the existing wireless LAN system has limitations in terms of seamless operation.

[0173] For example, in a single-AP environment, the AP and the STA (i.e., non-AP STA) are connected in a one-to-one form and cannot be established with another AP simultaneously. Therefore, in order for the STA to communicate with another AP (e.g., the second AP) for roaming, the STA needs to perform a disassociation process with the existing AP (e.g., the first AP) and repeat the authentication process and the association process with the new AP (e.g., the second AP). At this time, the longer the delay in performing this process, the longer the time (e.g., the time when the user, i.e., the STA, cannot communicate due to the disconnection of the wireless LAN connection (e.g., Wi-Fi connection) (e.g., the time when the user cannot access the Internet)).

[0174] Additionally or alternatively, the roaming delay (hereinafter referred to as the roaming delay) may be caused by buffered packet loss. For example, even if the data to be sent to the STA accumulates in the buffer of the first AP, if the STA moves to the second AP, the AP performs new buffering. At this time, due to the delay that occurs before the data enters the buffer of the second AP, a roaming delay may occur.

[0175] To solve the roaming delay as described above, the present disclosure proposes a new method based on a multi-AP scheme.

[0176] As described above, in the case of the AP configuration according to the single-AP scheme, information is not shared between APs. Therefore, in this case, it may be difficult to solve the roaming delay problems that may occur due to re-association, re-authentication, buffered packet loss, etc.

[0177] In contrast, in the case of the multi-AP scheme, information can be shared between APs and coordination can be achieved.

[0178] Therefore, based on the multi-AP scheme, the present disclosure proposes a method for establishing / configuring multi-associations of multiple APs to support seamless roaming.

[0179] In the method proposed in the present disclosure, the specific names of fields / sub-fields are merely examples and can be changed / replaced with other names, and the described STAs may include non-AP STAs and AP STAs.

[0180] For a clear explanation of the present disclosure, among the APs operating in a multi-AP scheme, the set of APs that form multiple associations with a STA is referred to as a multi-AP set.

[0181] Figure 11 An example of a multi-AP set according to an embodiment of the present disclosure is illustrated.

[0182] Referring to Figure 11 , MLD 1 and MLD 2 belong to ESS1, and MLD 3 belongs to ESS2. Here, MLD 1 is configured to support channels 1, 2, and 3, MLD 2 is configured to support channels 1 and 3, and MLD 3 is configured to support channels 2 and 3.

[0183] The multi-AP set proposed in the present disclosure may correspond to a set / group that groups APs MLDs belonging to the same ESS.

[0184] For example, MLD 1 and MLD 2 may be configured to belong to the same multi-AP set, and the multi-AP set may also include other APs MLDs that belong to the same ESS and support seamless roaming.

[0185] That is, the multi-BSSID (MBSSID) set corresponds to a set / group that groups the APs belonging to an AP MLD at a lower level than the MLD (e.g., the channel level), while the multi-AP set may correspond to a set / group that groups the APs MLDs at the MLD level. Therefore, the APs belonging to the multi-AP set may belong to the same MLD, the same MBSSID set, or neither.

[0186] Since the seamless roaming in the present disclosure is performed at the MLD level, seamless roaming can be used when moving from one AP MLD to another. In this case, seamless roaming can be achieved between the APs MLDs belonging to the multi-AP set. In this regard, when only changing the link within the same AP MLD, link transition can also be used.

[0187] Hereinafter, in order to establish / configure the above multi-association, a new reduced neighbor report (RNR) element and a multi-AP (multiple APs, Multi-AP) element are defined, and an association process based on these is proposed through specific examples.

[0188] First, the new RNR element proposed in the present disclosure is described.

[0189] The RNR element may include channels and other information for neighbor APs, and the RNR element may be sent via a beacon or the like.

[0190] In this regard, to support multi - association based on the multi - AP set proposed in the present disclosure, the primary AP may send partial information of other APs (i.e., slave APs) belonging to / included in the multi - AP set by adding the partial information to the RNR element. For example, the partial information may include information regarding channels, information regarding multi - AP IDs, information regarding AP addresses, etc.

[0191] The RNR element may be defined to include one or more neighbor AP information fields, where each neighbor AP information field may be defined to specify a target beacon transmission time (TBTT) and other information associated with a neighbor AP group.

[0192] Figure 12 Illustrated is a target beacon transmission time (TBTT) information field in a reduced neighbor report (RNR) element for multi - association according to an embodiment of the present disclosure.

[0193] The TBTT information field may include a multi - AP parameter sub - field. The sub - field may include information related to the multi - AP set to support multiple bindings proposed in the present disclosure.

[0194] In this regard, the TBTT information field may include one or more multi - AP parameter sub - fields for one or more APs (e.g., the primary AP and / or slave APs).

[0195] Here, each multi - AP parameter sub - field may be composed of a multi - AP set ID (Multi - AP set ID) sub - field, a beacon transmission power (Beacon Tx Power) sub - field, and a PER≤0.01 sub - field. Each sub - field may correspond to information required for the STA to determine whether to associate with each AP.

[0196] Specifically, the multi - AP set ID sub - field may be specified in a numerical form such as ADID or AID. The STA that receives the RNR element may identify / distinguish the multi - AP set to which the AP associated with the corresponding multi - AP parameter belongs through the multi - AP set ID sub - field.

[0197] The beacon transmission power sub - field indicates the transmission power used by the AP when sending a beacon and may be specified in dB.

[0198] The PER≤0.01 subfield may indicate information related to the packet error rate. Setting the value of the subfield to 1 may mean that the packet error rate value is 0.01 or less, and setting the value of the subfield to 0 may mean that the packet error rate value is 0.01 or greater / more than it.

[0199] During the discovery process, the AP (i.e., the primary AP) may include one or more multi-AP parameter subfields as described above in the RNR element and send it to the STA via a beacon. The STA that receives the beacon may select / decide the AP with which the STA wishes to associate based on the information included in the RNR element and may request additional information (e.g., complete information) about the AP from the AP that sent the beacon.

[0200] Figure 13 Illustrated is a multi-AP element for multi-association according to an embodiment of the present disclosure.

[0201] The multi-AP element proposed in the present disclosure may be included in a probe response frame or a (re)association request / response frame for transmission and reception during a multi-association process and be sent.

[0202] Refer to Figure 13 , the multi-AP element may be composed of a common information field and a multi-AP information field.

[0203] Here, the common information field may contain common information for the multi-AP (set).

[0204] The multi-AP information field may be configured in a sub-element format with complete information for each AP included in / belonging to the multi-AP set, i.e., a complete profile.

[0205] For example, the multi-AP information field may be composed of one or more sub-elements for one or more APs belonging to the multi-AP set (e.g., multi-AP N, where N is a positive integer greater than or equal to 1). Each multi-AP N sub-element (e.g., multi-AP1 sub-element, multi-AP 2 sub-element, etc.) may be composed of the information in the association response frame provided by the AP to the STA in a single-AP environment. That is, each multi-AP N sub-element may include the information provided by the AP for establishing an association with the corresponding AP. In this case, the information included in the common information field may not be included in each multi-AP N sub-element.

[0206] Figure 14 Illustrated is an association process for multi-association according to an embodiment of the present disclosure.

[0207] Refer to Figure 14, the association process is described by taking as an example the case where the multi-AP set is configured by three APs (i.e., AP 1, AP 2, and AP 3), but is not limited thereto, and can be extended and applied even when the multi-AP set is configured by a combination of different numbers of APs.

[0208] At this time, the transmission / reception process between AP 1 corresponding to the primary AP and the STA can be executed to establish / configure the multi-association for the multi-AP set.

[0209] The primary AP can continuously broadcast beacons to the surrounding STAs for discovery (S1410).

[0210] At this time, the AP can add partial information of other APs (e.g., AP 2, AP 3) included in the multi-AP set to the RNR element (e.g., Figure 11 the TBTT information field in the RNR element in

[0211] the beacon) and send this partial information.

[0212] The STA that receives the beacon sent by the primary AP can request the complete information of other APs (e.g., AP 2, AP 3) from the primary AP through a multi-AP probe request frame based on the partial information sent through the beacon (S1420). Figure 12

[0212] The primary AP can send the complete information of other APs (e.g., AP 2, AP 3) in the multi-AP element (e.g., Figure 12 the multi-AP element in

[0213] to the STA through the multi-AP probe request frame (S1430).

[0213] In this regard, the transmission and reception of the probe request / response frames can be referred to as multi-AP probing, and can correspond to an enhanced discovery process for all APs included in the multi-AP set. In this case, the transmission and reception of the probe request / response frames can be omitted based on a predefined configuration / condition.

[0214] The STA that receives the complete information of other APs (e.g., AP 2, AP 3) can send an association request frame to the primary AP based on this information (S1440) and receive an association response frame from the primary AP (S1450). Through the transmission and reception of such association request / response frames, the STA can establish a multi-association with all APs included in the multi-AP set.

[0215] In this regard, the above multi-AP element (e.g., Figure 13 the multi-AP element in

[0216] After that, data transmission and reception between the STA and the multi-AP set can be performed (S1460). At this time, the data transmission and reception can be performed based on seamless roaming between the APs belonging to the multi-AP set and / or link switching for some links.

[0217] Hereinafter, operations of the STA and the AP for establishing multi-association of the multi-AP set according to an embodiment of the present disclosure will be described.

[0218] Figure 15 and Figure 16 Examples can correspond to some of the various examples of the present disclosure.

[0219] Figure 15 is a schematic diagram for explaining the operation of the STA for establishing multi-association according to an embodiment of the present disclosure.

[0220] The STA can receive a beacon frame including information related to the AP set to which the specific AP belongs from the specific AP (S1510).

[0221] Here, the specific AP can correspond to the above-mentioned primary AP in the present disclosure. For example, the specific AP can correspond to an AP configured to control and manage links with other APs among the APs belonging to the AP set.

[0222] In addition, the AP set can correspond to the multi-AP set in the present disclosure, and can be configured with APs attached to different AP MLDS supporting multi-links (for example, see Figure 11 ).

[0223] For example, the information related to the AP set can include at least one of the following items: identification information for the AP set, information for the beacon transmission power, or information for the packet error rate associated with each AP belonging to the AP set.

[0224] In this regard, the information related to the AP set can be included in the reduced neighbor report (RNR) element included in the beacon frame. Specifically, the information related to the AP set can be included after the multi-link device (MLD) parameter subfield in the target beacon transmission time (TBTT) information field in the RNR element (for example, see Figure 12 ).

[0225] The STA can send a first frame requesting association (i.e., multi-association) between the multiple APs belonging to the AP set and the STA to the specific AP (S1520). For example, the multiple APs can be selected / determined among the APs belonging to the AP set based on at least one of the information for the beacon transmission power or the information for the packet error rate.

[0226] After that, the STA can receive a second frame corresponding to the response to the first frame from a specific AP (S1530).

[0227] For example, the first frame can correspond to an association request frame, and the second frame can correspond to an association response frame.

[0228] In this regard, at least one of the first frame or the second frame can include association-related information for each AP included in a plurality of APs (for example, see Figure 13 ). As a specific example, the association-related information for each AP is configured in a sub-element format within a specific element related to the AP set, and the specific element can also include common information for the AP set (for example, see Figure 13 ).

[0229] In this regard, the information related to the AP set in step S1510 can include partial information for each AP, and the combined related information in step S1520 and / or step S1530 can include complete information for each AP.

[0230] Additionally or alternatively, the STA can send a probe request frame related to the AP set to a specific AP and receive a probe response frame corresponding to the response to the probe request frame from the specific AP (for example, see Figure 14 ).

[0231] Figure 15 The method performed by the STA described in the example of Figure 1 can be performed by the first device (100) of Figure 1 . For example,

[0232] one or more processors (102) of the first device (100) can be configured to receive a beacon frame from an AP (200), send the first frame, and receive the second frame through one or more transceivers (106).

[0233] For example, one or more processors (102) of the first device (100) can be configured to decode the information related to the AP set included in the beacon frame and configure the first frame to request an association between the first device (100), i.e., the STA, and a plurality of APs (200) belonging to the AP set. In addition, one or more processors (102) of the first device (100) can be configured to decode the second frame corresponding to the response to the first frame and establish an association with the plurality of APs (200).

[0233] In addition, one or more memories (104) of the first device (100) can store instructions that, when executed by one or more processors (102), perform the Figure 15 method described in the example of

[0234] Figure 16 It is a schematic diagram for explaining the operation of establishing a multi-associated AP according to an embodiment of the present disclosure.

[0235] The AP may send a beacon frame including information related to the AP set to which the AP belongs to the STA (S1610).

[0236] Here, the AP may correspond to the above-mentioned master AP in the present disclosure. For example, the AP may correspond to an AP set configured to control and manage links with other APs among the APs belonging to the AP set.

[0237] The AP may receive a first frame from the STA to request an association (i.e., multi-association) between multiple APs belonging to the AP set and the STA (S1620).

[0238] After that, the AP may send a second frame corresponding to the response to the first frame to the STA (S1630).

[0239] In this regard, at least one of the first frame or the second frame may include association-related information for each AP included in the multiple APs (for example, see Figure 13 ).

[0240] In Figure 16 's example, the specific details of the AP set, the information related to the AP set, the first frame, the second frame, and the combined related information are the same as those described in Figure 15 's example, so redundant descriptions are omitted.

[0241] Figure 16 The method performed by the STA described in the example of Figure 1 may be performed by the second device (200) of Figure 1 . For example,

[0242] One or more processors (202) of the second device (200) may be configured to send a beacon frame to the STA (100), receive the first frame, and send the second frame through one or more transceivers (206).

[0243] For example, one or more processors (202) of the second device (200) may be configured to encode information related to the AP set to configure the beacon frame, decode the first frame for requesting an association between multiple APs (200) belonging to the AP set and the first device (100), i.e., the STA, and configure a second frame corresponding to the response to the first frame based on the first frame. Figure 16 In addition, one or more memories (204) of the second device (200) may store instructions that, when executed by one or more processors (202), perform the method described in the example of

[0244] In a conventional wireless LAN system, when roaming is performed between APs due to the movement of a STA or the like, the association with the existing AP should be released, and the authentication and association processes for the new AP should be performed again. That is, in a conventional wireless LAN system, a STA may be associated with only one AP. In this case, since the association process should be performed again, a delay inevitably occurs before roaming is completed.

[0245] In contrast, in the case of the method of the present disclosure, by forming multiple associations with multiple APs, a new association process is not required when roaming between APs. That is, according to the method proposed in the present disclosure, a new effect can be achieved that can alleviate the delay problem that may occur when roaming to another AP.

[0246] The above-described embodiments combine the elements and features of the present disclosure in a predetermined form. Unless otherwise explicitly mentioned, each element or feature should be regarded as optional. Each element or feature can be implemented in a form that does not combine with other elements or features. In addition, the embodiments of the present disclosure may include combining some elements and / or features. The order of operations described in the embodiments of the present disclosure can be changed. Some elements or features of one embodiment may be included in other embodiments, or may be replaced with corresponding elements or features of other embodiments. Obviously, the embodiments may include combining claims that do not have an explicit citation relationship in the claims, or may be included as new claims by amendment after the application.

[0247] Those skilled in the relevant art will appreciate that the present disclosure can be implemented in other specific forms without departing from the essential features of the present disclosure. Therefore, the above detailed description should not be construed restrictively in every aspect, but should be considered illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all changes within the equivalent scope of the present disclosure are included within the scope of the present disclosure.

[0248] The scope of the present disclosure includes software or machine-executable commands (e.g., operating systems, applications, firmware, programs, etc.) that perform operations according to various embodiments in a device or computer, and non-transitory computer-readable media that cause the software or commands, etc. to be stored and executable in the device or computer. Commands that can be used to program a processing system for performing the features described in the present disclosure can be stored in a storage medium or computer-readable storage medium, and the features described in the present disclosure can be implemented by using a computer program product including such a storage medium. The storage medium can include high-speed random access memory, for example, DRAM, SRAM, DDR RAM, or other random access solid-state storage devices, but is not limited thereto, and it can include non-volatile memory, for example, one or more disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory optionally includes one or more storage devices located remotely from the processor. The memory, or alternatively, the non-volatile memory device in the memory, includes a non-transitory computer-readable storage medium. The features described in the present disclosure can be stored in any kind of machine-readable medium to control the hardware of the processing system, and can be integrated into software and / or firmware that allows the processing system to interact with other mechanisms using the results from the embodiments of the present disclosure. Such software or firmware can include application code, device drivers, operating systems, and execution environments / containers, but is not limited thereto.

[0249] Industrial Applicability

[0250] The method proposed by the present disclosure is mainly described based on examples applied to IEEE 802.11-based systems, but can be applied to various WLAN or wireless communication systems other than IEEE 802.11-based systems.

Claims

1. A method performed by a station STA in a wireless LAN system, the method comprising: receiving, from a specific access point AP, a beacon frame including information related to an AP set to which the specific AP belongs; sending, to the specific AP, a first frame for requesting association between a plurality of APs belonging to the AP set and the STA; and receiving, from the specific AP, a second frame corresponding to a response to the first frame, wherein at least one of the first frame or the second frame includes association-related information for each AP included in the plurality of APs.

2. The method according to claim 1, wherein the information related to the AP set includes at least one of the following: identification information for the AP set, information for beacon transmission power, or information for packet error rate related to each AP belonging to the AP set.

3. The method according to claim 2, wherein the plurality of APs are selected among the APs belonging to the AP set based on at least one of the information for beacon transmission power and the information for packet error rate.

4. The method according to claim 1, wherein the information related to the AP set is included in a reduced neighbor report RNR element included in the beacon frame.

5. The method according to claim 4, wherein the information related to the AP set is included after a multi-link device MLD parameter subfield in a target beacon transmission time TBTT information field within the RNR element.

6. The method according to claim 1, wherein the first frame corresponds to an association request frame, and the second frame corresponds to an association response frame.

7. The method according to claim 1, wherein the information related to the AP set includes partial information for each AP, and wherein the association-related information includes complete information for each AP.

8. The method according to claim 1, wherein the specific AP corresponds to an AP configured to control and manage links with other APs among the APs belonging to the AP set.

9. The method according to claim 1, wherein the association-related information for each AP is configured in a specific element related to the AP set in a sub-element format, and wherein the specific element further includes common information for the AP set.

10. The method according to claim 1, the method further comprising: sending, to the specific AP, a probe request frame related to the AP set; and receiving, from the specific AP, a probe response frame corresponding to a response to the probe request frame, wherein the probe response frame includes association-related information for each AP belonging to the AP set.

11. The method according to claim 1, wherein the AP set is configured with APs attached to different AP MLDs supporting multi-link.

12. An apparatus for a first station STA in a wireless local area network WLAN system, the apparatus comprising: at least one transceiver; and At least one processor, the at least one processor being connected to the at least one transceiver, wherein the at least one processor is configured to: Receive a beacon frame from a specific access point AP, the beacon frame including information related to a set of APs to which the specific AP belongs; Send a first frame to the specific AP for requesting an association between a plurality of APs belonging to the set of APs and the STA; and Receive a second frame corresponding to a response to the first frame from the specific AP, wherein at least one of the first frame or the second frame includes association-related information for each AP included in the plurality of APs.

13. A method performed by an access point AP in a wireless LAN system, the method comprising: Sending a beacon frame including information related to a set of APs to which the AP belongs to a station STA; Receiving a first frame from the STA for requesting an association between a plurality of APs belonging to the set of APs and the STA; and And Sending a second frame corresponding to a response to the first frame to the STA, wherein at least one of the first frame or the second frame includes association-related information for each AP included in the plurality of APs.

14. An apparatus for an access point AP in a wireless local area network WLAN system, the apparatus comprising: At least one transceiver; And At least one processor, the at least one processor being connected to the at least one transceiver, wherein the at least one processor is configured to: Send a beacon frame including information related to a set of APs to which the AP belongs to a station STA; Receive a first frame from the STA for requesting an association between a plurality of APs belonging to the set of APs and the STA; and Send a second frame corresponding to a response to the first frame to the STA, wherein at least one of the first frame or the second frame includes association-related information for each AP included in the plurality of APs.

15. A processing unit configured to control a station STA in a wireless local area network WLAN system, the processing unit comprising: At least one processor; And At least one computer memory, the at least one computer memory being operatively connected to the at least one processor and storing instructions that, when executed by the at least one processor, are for performing the method according to any one of claims 1 to 11.

16. At least one non-transitory computer-readable medium storing at least one instruction, wherein the at least one instruction, when executed by at least one processor, controls a device in a wireless local area network WLAN system to perform the method according to any one of claims 1 to 11.

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