Method and device for requesting MLD roaming by checking in advance whether AP can roam in wireless LAN system

Abstract

A method and a device for requesting MLD roaming by checking in advance whether an AP can roam in a wireless LAN system are presented. Particularly, a first non-AP STA receives a management frame from a first AP. The first non-AP STA determines roaming from the first AP to a second AP on the basis of the management frame. The first AP belongs to a first AP MLD and the second AP belongs to a second AP MLD. The management frame includes first information about whether the second AP is included in a roaming-enabled group, which is the same as that of the first AP. On the basis of the first information being set to 1, the second AP is included in the roaming-enabled group, which is the same as that of the first AP. On the basis of the first information being set to 0, the second AP is not included in the roaming-enabled group, which is the same as that of the first AP.

Description

Method and device for requesting MLD roaming by checking in advance whether the AP is capable of roaming in a wireless LAN system

[0001] This specification relates to a technique for requesting MLD roaming by checking in advance whether an AP is capable of roaming in a wireless LAN system, and more specifically, to a method and device for notifying in a management frame whether an AP to be roamed belongs to the same mobility area or the same roaming-capable group.

[0002] Wireless local area networks (WLANs) have been improved in various ways. For example, the IEEE 802.11ax standard proposed an improved communication environment using orthogonal frequency division multiple access (OFDMA) and downlink multi-user multiple input, multiple output (DL MU MIMO) techniques.

[0003] This specification proposes technical features that can be utilized in a new communications standard. For example, the new communications standard could be the Extreme High Throughput (EHT) standard, which is currently under discussion. The EHT standard could utilize newly proposed increased bandwidth, an improved PHY layer protocol data unit (PPDU) structure, improved sequences, and the Hybrid Automatic Repeat Request (HARQ) technique. The EHT standard could also be referred to as the IEEE 802.11be standard.

[0004] New wireless LAN standards may allow for an increased number of spatial streams. This may necessitate improvements to signaling techniques within the wireless LAN system to properly utilize these increased spatial streams.

[0005] This specification proposes a method and device for requesting MLD roaming by checking in advance whether an AP is capable of roaming in a wireless LAN system.

[0006] An example of this specification proposes a method for requesting MLD roaming by checking in advance whether the AP is capable of roaming.

[0007] The present embodiment can be performed in a network environment that supports a next-generation wireless LAN system (UHR (Ultra High Reliability) wireless LAN system or next wi-fi). The next-generation wireless LAN system is a wireless LAN system that improves the 802.11be system and can satisfy backward compatibility with the 802.11be system.

[0008] This embodiment is performed in a receiving STA, and the receiving STA may correspond to at least one STA (station). The transmitting STA may correspond to an AP (access point).

[0009] The present embodiment proposes a method for notifying a non-AP MLD (or non-AP STA) when roaming to another AP whether the other AP belongs to the same mobility domain or the same roaming-enabled group. In particular, the present embodiment has the effect of enabling seamless roaming without re-authentication and re-association with the AP to which the STA is trying to roam by notifying in advance through a management frame whether the other AP is capable of roaming.

[0010] The first non-AP STA (non-access point station) receives a management frame from the first AP.

[0011] The above first non-AP STA decides to roam from the first AP to the second AP based on the management frame.

[0012] The first AP is affiliated with the first AP MLD (multi-link device), and the second AP is affiliated with the second AP MLD. Since the first and second APs are affiliated with different AP MLDs, the AP MLD IDs of the first and second APs may be set to different values.

[0013] The above management frame includes first information on whether the second AP is included in the same roaming-enabled group as the first AP. The first information may be referred to as a Same UHR AP MLD indicator.

[0014] Based on the first information being set to 1, the second AP is included in the same roaming-enabled group as the first AP. Based on the first information being set to 0, the second AP is not included in the same roaming-enabled group as the first AP (i.e., the second AP is included in a different roaming-enabled group than the first AP).

[0015] The first AP may be referred to as an Old AP (O_AP), a Serving AP, or a Current AP. The second AP may be referred to as a New AP (N_AP) or a Target AP. The first AP MLD including the first AP may be referred to as a Serving AP MLD. The second AP MLD including the second AP may be referred to as a Target AP MLD.

[0016] The above roaming-enabled group may be referred to as a UHR AP MLD. The first and second AP MLDs are non-collocated, but are included in the same roaming-enabled group, so roaming (or movement) from an AP in the first AP MLD to an AP in the second AP MLD may be possible. The APs in the first AP MLD are collocated. The APs in the second AP MLD are also collocated.

[0017] This embodiment includes first information (UHR AP MLD Indication) in the management frame, enabling a non-AP STA to determine whether an AP is roamable before requesting roaming. This prevents requests for information about APs to which roaming is not possible, thereby preventing unnecessary resource consumption. In addition, it resolves packet loss and delay, enabling seamless movement to another AP.

[0018] Figure 1 illustrates an example of a transmitting device and / or a receiving device of the present specification.

[0019] Figure 2 is a conceptual diagram showing the structure of a wireless local area network (WLAN).

[0020] Figure 3 is a diagram illustrating a general link setup process.

[0021] Figure 4 illustrates one embodiment of a multi-link (ML).

[0022] FIG. 5 illustrates a PPDU (physical protocol data unit or physical layer (PHY) protocol data unit) transmitted / received by an STA of this specification.

[0023] Figure 6 is a diagram showing the layout of resource units (RUs) used for 20MHz PPDU.

[0024] Figure 7 is a diagram showing the layout of resource units (RUs) used for 40MHz PPDU.

[0025] Figure 8 is a diagram showing the layout of resource units (RUs) used for 80MHz PPDU.

[0026] Figure 9 shows the operation according to UL-MU.

[0027] Figure 10 shows an example of channels used / supported / defined within the 2.4 GHz band.

[0028] Figure 11 illustrates an example of channels used / supported / defined within the 5 GHz band.

[0029] Figure 12 illustrates an example of channels used / supported / defined within the 6 GHz band.

[0030] Figure 13 shows an example of a header of a MAC frame.

[0031] FIG. 14 illustrates a modified example of a transmitting device and / or a receiving device of the present specification.

[0032] Figure 15 illustrates an over-the-air (OTA) FT protocol in a Robust Security Network (RSN).

[0033] Figure 16 illustrates the high-level architecture for AP MLD.

[0034] Figure 17 illustrates an example of a high-level architecture for UHR AP MLD.

[0035] Figure 18 illustrates another example of a high-level architecture for UHR AP MLD.

[0036] Figure 19 illustrates an example of a UHR AP MLD structure for roaming.

[0037] Figure 20 illustrates an example of an RNR IE containing MLD Roaming information.

[0038] Figure 21 illustrates an example where the Common Info field includes the Same UHR AP MLD indicator.

[0039] Figure 22 illustrates an example where the Link Info field includes the Same UHR AP MLD indicator (Mandatory).

[0040] Figure 23 illustrates an example where the Link Info field includes the Same UHR AP MLD indicator (Optional).

[0041] Figure 24 is an example of a multi-link probe request / response using the Same UHR AP MLD indicator.

[0042] Figure 25 shows a flowchart illustrating the roaming process.

[0043] Figure 26 illustrates an example of primitive parameters of DS-STA-NOTIFY.request.

[0044] Fig. 27 is a flowchart illustrating the operation of a transmitting device according to the present embodiment.

[0045] Fig. 28 is a flowchart illustrating the operation of a receiving device according to the present embodiment.

[0046] Fig. 29 is a flowchart illustrating a procedure for performing MLD roaming by checking whether an AP according to the present embodiment is an AP capable of roaming.

[0047] Figure 30 is a flowchart illustrating a procedure for performing MLD roaming by checking whether an STA according to the present embodiment is an AP capable of roaming.

[0048] In this specification, “A or B” can mean “only A,” “only B,” or “both A and B.” In other words, “A or B” in this specification can be interpreted as “A and / or B.” For example, “A, B or C” in this specification can mean “only A,” “only B,” “only C,” or “any combination of A, B, and C.”

[0049] As used herein, a slash ( / ) or a comma can mean "and / or." For example, "A / B" can mean "and / or B." Accordingly, "A / B" can mean "only A," "only B," or "both A and B." For example, "A, B, C" can mean "A, B, or C."

[0050] In this specification, “at least one of A and B” can mean “only A,” “only B,” or “both A and B.” Additionally, in this specification, the expressions “at least one of A or B” or “at least one of A and / or B” can be interpreted identically to “at least one of A and B.”

[0051] In addition, parentheses used in this specification may mean “for example.” Specifically, when “control information (UHR-Signal field)” is indicated, the “UHR-Signal field” may be suggested as an example of “control information.” In other words, the “control information” in this specification is not limited to the “UHR-Signal field,” and the “UHR-Signal field” may be suggested as an example of “control information.” In addition, even when indicated as “control information (UHR-Signal field),” the “UHR-Signal field” may be suggested as an example of “control information.”

[0052] Additionally, as used herein, “a / an” can mean “at least one” or “one or more.” Additionally, terms ending in “(s)” can mean “at least one” or “one or more.”

[0053] Additionally, the expressions “based on” or “on the basis of” or “according to” used herein mean “based at least in part on” and not “based solely on.”

[0054] Technical features individually described in a single drawing in this specification may be implemented individually or simultaneously.

[0055] The following examples of this specification can be applied to various wireless communication systems. For example, the following examples of this specification can be applied to wireless local area network (WLAN) systems. For example, the present specification can be applied to the IEEE 802.11a / g / n / ac / ax / be / bn standards. In addition, the examples of this specification can be applied to the Ultra High Reliability (UHR) standard or the next-generation wireless LAN standard that enhances IEEE 802.11bn. In addition, the examples of this specification can be applied to mobile communication systems. For example, the examples of this specification can be applied to mobile communication systems based on Long Term Evolution (LTE) and its evolution based on the 3rd Generation Partnership Project (3GPP) standard.

[0056] In order to explain the technical features of this specification, the technical features to which this specification can be applied are described below.

[0057] Figure 1 illustrates an example of a transmitting device and / or a receiving device of the present specification.

[0058] An example of FIG. 1 can perform various technical features described below. FIG. 1 relates to at least one STA (station). For example, the STA (110, 120) of the present specification may also be referred to by various names such as a mobile terminal, a wireless device, a Wireless Transmit / Receive Unit (WTRU), a User Equipment (UE), a Mobile Station (MS), a Mobile Subscriber Unit, or simply a user. The STA (110, 120) of the present specification may also be referred to by various names such as a network, a base station, a Node-B, an access point (AP), a repeater, a router, a relay, etc. The STA (110, 120) of the present specification may also be referred to by various names such as a receiving apparatus, a transmitting apparatus, a receiving STA, a transmitting STA, a receiving device, a transmitting device, etc.

[0059] For example, STA (110, 120) may perform the role of an AP (access point) or a non-AP role. That is, STA (110, 120) of the present specification may perform the functions of an AP and / or a non-AP. In the present specification, AP may also be indicated as an AP STA.

[0060] The STA (110, 120) of this specification can support various communication standards other than the IEEE 802.11 standard. For example, it can support communication standards according to the 3GPP standard (e.g., LTE, LTE-A, 5G NR standard). In addition, the STA of this specification can be implemented in various devices such as mobile phones, vehicles, and personal computers. In addition, the STA of this specification can support communication for various communication services such as voice calls, video calls, data communications, and autonomous driving (Self-Driving, Autonomous-Driving).

[0061] In this specification, STA (110, 120) may include a medium access control (MAC) and a physical layer interface for a wireless medium that follow the provisions of the IEEE 802.11 standard.

[0062] Based on the sub-drawing (a) of Fig. 1, STA (110, 120) is described as follows.

[0063] The first STA (110) may include a processor (111), a memory (112), and a transceiver (113). The illustrated processor, memory, and transceiver may each be implemented as separate chips, or at least two blocks / functions may be implemented through a single chip.

[0064] The transceiver (113) of the first STA performs signal transmission and reception operations. Specifically, it can transmit and receive IEEE 802.11 packets (e.g., IEEE 802.11a / b / g / n / ac / ax / be, etc.).

[0065] For example, the first STA (110) can perform the intended operation of the AP. For example, the processor (111) of the AP can receive a signal through the transceiver (113), process the received signal, generate a transmission signal, and perform control for signal transmission. The memory (112) of the AP can store a signal received through the transceiver (113) (i.e., a reception signal) and store a signal to be transmitted through the transceiver (i.e., a transmission signal).

[0066] For example, the second STA (120) can perform the intended operation of a non-AP STA. For example, the transceiver (123) of the non-AP performs signal transmission and reception operations. Specifically, it can transmit and receive IEEE 802.11 packets (e.g., IEEE 802.11a / b / g / n / ac / ax / be, etc.).

[0067] For example, the processor (121) of the Non-AP STA can receive a signal through the transceiver (123), process the received signal, generate a transmission signal, and perform control for signal transmission. The memory (122) of the Non-AP STA can store a signal received through the transceiver (123) (i.e., a reception signal) and store a signal to be transmitted through the transceiver (i.e., a transmission signal).

[0068] For example, in the specification below, the operation of a device indicated as AP may be performed in the first STA (110) or the second STA (120). For example, if the first STA (110) is an AP, the operation of the device indicated as AP may be controlled by the processor (111) of the first STA (110), and a related signal may be transmitted or received through a transceiver (113) controlled by the processor (111) of the first STA (110). In addition, control information related to the operation of the AP or a transmission / reception signal of the AP may be stored in the memory (112) of the first STA (110). In addition, when the second STA (110) is an AP, the operation of the device indicated as an AP is controlled by the processor (121) of the second STA (120), and a related signal can be transmitted or received through a transceiver (123) controlled by the processor (121) of the second STA (120). In addition, control information related to the operation of the AP or the transmission / reception signal of the AP can be stored in the memory (122) of the second STA (110).

[0069] For example, in the specification below, the operation of a device indicated as a non-AP (or User-STA) may be performed in the STA (110) or the second STA (120). For example, if the second STA (120) is a non-AP, the operation of the device indicated as a non-AP may be controlled by the processor (121) of the second STA (120), and a related signal may be transmitted or received through a transceiver (123) controlled by the processor (121) of the second STA (120). In addition, control information related to the operation of the non-AP or the transmission / reception signal of the AP may be stored in the memory (122) of the second STA (120). For example, if the first STA (110) is a non-AP, the operation of a device indicated as a non-AP is controlled by the processor (111) of the first STA (110), and a related signal may be transmitted or received through a transceiver (113) controlled by the processor (111) of the first STA (120). In addition, control information related to the operation of the non-AP or the transmission / reception signal of the AP may be stored in the memory (112) of the first STA (110).

[0070] In the following specification, devices called (transmitting / receiving) STA, first STA, second STA, STA1, STA2, AP, first AP, second AP, AP1, AP2, (transmitting / receiving) Terminal, (transmitting / receiving) device, (transmitting / receiving) apparatus, network, etc. may refer to the STA (110, 120) of FIG. 1. For example, devices indicated as (transmitting / receiving) STA, first STA, second STA, STA1, STA2, AP, first AP, second AP, AP1, AP2, (transmitting / receiving) Terminal, (transmitting / receiving) device, (transmitting / receiving) apparatus, network, etc. without specific drawing symbols may also refer to the STA (110, 120) of FIG. 1. For example, in the example below, the operation of various STAs transmitting and receiving signals (e.g., PPDUs) may be performed by the transceivers (113, 123) of FIG. 1. In addition, in the example below, the operation of various STAs generating transmission and reception signals or performing data processing or calculations in advance for transmission and reception signals may be performed by the processors (111, 121) of FIG. 1.For example, an example of an operation that generates a transmission / reception signal or performs data processing or operation in advance for a transmission / reception signal may include 1) an operation of determining / obtaining / configuring / computing / decoding / encoding bit information of a subfield (SIG, STF, LTF, Data) field included in a PPDU, 2) an operation of determining / configuring / obtaining time resources or frequency resources (e.g., subcarrier resources) used for a subfield (SIG, STF, LTF, Data) field included in a PPDU, 3) an operation of determining / configuring / obtaining a specific sequence (e.g., a pilot sequence, an STF / LTF sequence, an extra sequence applied to SIG) used for a subfield (SIG, STF, LTF, Data) field included in a PPDU, 4) a power control operation and / or a power saving operation applied to an STA, 5) an operation related to determining / obtaining / configuring / computing / decoding / encoding an ACK signal, etc. Additionally, in the examples below, various information (e.g., information related to fields / subfields / control fields / parameters / power, etc.) used by various STAs for determining / acquiring / configuring / computing / decoding / encoding transmission / reception signals can be stored in the memory (112, 122) of FIG. 1.

[0071] The device / STA of the sub-drawing (a) of the above-described FIG. 1 can be modified as in the sub-drawing (b) of FIG. 1. Hereinafter, the STA (110, 120) of the present specification will be described based on the sub-drawing (b) of FIG. 1.

[0072] For example, the transceiver (113, 123) illustrated in sub-drawing (b) of FIG. 1 may perform the same function as the transceiver illustrated in sub-drawing (a) of FIG. 1 described above. For example, the processing chip (114, 124) illustrated in sub-drawing (b) of FIG. 1 may include a processor (111, 121) and a memory (112, 122). The processor (111, 121) and the memory (112, 122) illustrated in sub-drawing (b) of FIG. 1 may perform the same function as the processor (111, 121) and the memory (112, 122) illustrated in sub-drawing (a) of FIG. 1 described above.

[0073] The mobile terminal, wireless device, Wireless Transmit / Receive Unit (WTRU), User Equipment (UE), Mobile Station (MS), Mobile Subscriber Unit, user, user STA, network, Base Station, Node-B, Access Point (AP), repeater, router, relay, receiving device, transmitting device, receiving STA, transmitting STA, receiving Device, transmitting Device, receiving Apparatus, and / or transmitting Apparatus described below may refer to the STA (110, 120) illustrated in the sub-drawings (a) / (b) of FIG. 1, or may refer to the processing chip (114, 124) illustrated in the sub-drawing (b) of FIG. 1. That is, the technical feature of the present specification may be performed in the STA (110, 120) illustrated in the sub-drawings (a) / (b) of FIG. 1, or may be performed only in the processing chip (114, 124) illustrated in the sub-drawings (b) of FIG. 1. For example, the technical feature that the transmitting STA transmits a control signal may be understood as a technical feature that the control signal generated in the processor (111, 121) illustrated in the sub-drawings (a) / (b) of FIG. 1 is transmitted through the transceiver (113, 123) illustrated in the sub-drawings (a) / (b) of FIG. 1. Alternatively, the technical feature that the transmitting STA transmits a control signal may be understood as a technical feature that the control signal to be transmitted to the transceiver (113, 123) is generated in the processing chip (114, 124) illustrated in the sub-drawings (b) of FIG. 1.

[0074] For example, the technical feature of a receiving STA receiving a control signal can be understood as a technical feature of a control signal being received by a transceiver (113, 123) illustrated in sub-drawing (a) of FIG. 1. Alternatively, the technical feature of a receiving STA receiving a control signal can be understood as a technical feature of a control signal received by a transceiver (113, 123) illustrated in sub-drawing (a) of FIG. 1 being acquired by a processor (111, 121) illustrated in sub-drawing (a) of FIG. 1. Alternatively, the technical feature of a receiving STA receiving a control signal can be understood as a technical feature of a control signal received by a transceiver (113, 123) illustrated in sub-drawing (b) of FIG. 1 being acquired by a processing chip (114, 124) illustrated in sub-drawing (b) of FIG.

[0075] Referring to the sub-drawing (b) of FIG. 1, software code (115, 125) may be included in the memory (112, 122). The software code (115, 125) may include instructions that control the operation of the processor (111, 121). The software code (115, 125) may be included in various programming languages.

[0076] The processor (111, 121) or processing chip (114, 124) illustrated in FIG. 1 may include an application-specific integrated circuit (ASIC), another chipset, a logic circuit, and / or a data processing device. The processor may be an application processor (AP). For example, the processor (111, 121) or processing chip (114, 124) illustrated in FIG. 1 may include at least one of a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), and a modem (modulator and demodulator). For example, the processor (111, 121) or processing chip (114, 124) illustrated in FIG. 1 may be a SNAPDRAGON™ series processor manufactured by Qualcomm®, an EXYNOSTM series processor manufactured by Samsung®, an A series processor manufactured by Apple®, a HELIO™ series processor manufactured by MediaTek®, an ATOM™ series processor manufactured by INTEL®, or an enhanced processor thereof.

[0077] In this specification, uplink may mean a link for communication from a non-AP STA to an AP STA, and uplink PPDU / packet / signal, etc. may be transmitted through the uplink. In addition, in this specification, downlink may mean a link for communication from an AP STA to a non-AP STA, and downlink PPDU / packet / signal, etc. may be transmitted through the downlink.

[0078] Figure 2 is a conceptual diagram showing the structure of a wireless local area network (WLAN).

[0079] The upper part of Figure 2 shows the structure of the infrastructure BSS (basic service set) of IEEE (institute of electrical and electronic engineers) 802.11.

[0080] The upper part of Figure 2 shows the structure of the infrastructure BSS (basic service set) of IEEE (institute of electrical and electronic engineers) 802.11.

[0081] Referring to the top of FIG. 2, the wireless LAN system may include one or more infrastructure BSSs (200, 205) (hereinafter, BSS). The BSSs (200, 205) are a collection of APs and STAs, such as an access point (AP) 225 and a station (STA1, 200-1), that have successfully synchronized and can communicate with each other, and are not a concept that designates a specific area. The BSS (205) may also include one or more STAs (205-1, 205-2) that can be associated with one AP (230).

[0082] A BSS may include at least one STA, an AP (225, 230) providing a distribution service, and a distribution system (DS, 210) connecting multiple APs.

[0083] A distributed system (210) can connect multiple BSSs (200, 205) to implement an extended service set (ESS, 240). An ESS (240) can be used as a term to indicate a network formed by connecting one or more APs through the distributed system (210). APs included in a single ESS (240) can have the same SSID (service set identification).

[0084] The portal (portal, 220) can act as a bridge to connect a wireless LAN network (IEEE 802.11) to another network (e.g., 802.X).

[0085] In a BSS such as the upper part of Fig. 2, a network between APs (225, 230) and a network between APs (225, 230) and STAs (200-1, 205-1, 205-2) can be implemented. However, it may also be possible to establish a network and perform communication between STAs without an AP (225, 230). A network that establishes a network and performs communication between STAs without an AP (225, 230) is defined as an ad-hoc network or an independent basic service set (IBSS).

[0086] The bottom of Figure 2 is a conceptual diagram showing IBSS.

[0087] Referring to the bottom of Fig. 2, the IBSS is a BSS that operates in ad-hoc mode. Since the IBSS does not include an AP, there is no centralized management entity. That is, in the IBSS, the STAs (250-1, 250-2, 250-3, 255-4, 255-5) are managed in a distributed manner. In the IBSS, all STAs (250-1, 250-2, 250-3, 255-4, 255-5) can be mobile STAs, and access to the distributed system is not permitted, forming a self-contained network.

[0088] Figure 3 is a diagram illustrating a general link setup process.

[0089] In step S310, the STA may perform a network discovery operation. This network discovery operation may include scanning by the STA. That is, for the STA to access the network, it must find a network it can join. Before joining a wireless network, the STA must identify compatible networks. The process of identifying networks in a specific area is called scanning. Scanning methods include active scanning and passive scanning.

[0090] Figure 3 illustrates a network discovery operation that includes an active scanning process as an example. In active scanning, an STA performing scanning transmits a probe request frame to discover which APs exist in the vicinity while moving between channels and waits for a response. A responder transmits a probe response frame to the STA that transmitted the probe request frame in response to the probe request frame. Here, the responder may be the STA that last transmitted a beacon frame in the BSS of the channel being scanned. In a BSS, the AP transmits the beacon frame, so the AP becomes the responder. In an IBSS, the STAs within the IBSS take turns transmitting beacon frames, so the responder is not constant. For example, an STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 can store BSS-related information included in the received probe response frame and move to the next channel (e.g., channel 2) to perform scanning (i.e., transmitting and receiving probe requests / responses on channel 2) in the same manner.

[0091] Although not shown in the example of FIG. 3, the scanning operation can also be performed in a passive scanning manner. An STA performing scanning based on passive scanning can wait for a beacon frame while moving between channels. A beacon frame is one of the management frames in IEEE 802.11. It announces the presence of a wireless network and is periodically transmitted so that the scanning STA can find the wireless network and participate in the wireless network. In the BSS, the AP periodically transmits the beacon frame, and in the IBSS, the STAs within the IBSS take turns transmitting the beacon frame. When the scanning STA receives a beacon frame, it stores the information about the BSS included in the beacon frame and moves to another channel, recording the beacon frame information on each channel. An 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 scanning on the next channel in the same manner.

[0092] An STA that discovers a network can perform an authentication process through step S320. This authentication process may be referred to as the first authentication process to clearly distinguish it from the security setup operation of step S340 described below. The authentication process of S320 may include a process in which the STA transmits an authentication request frame to the AP, and the AP responds by transmitting an authentication response frame to the STA. The authentication frame used for the authentication request / response corresponds to a management frame.

[0093] The authentication frame may include information such as an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a Robust Security Network (RSN), and a Finite Cyclic Group.

[0094] An STA can transmit an authentication request frame to an AP. The AP can determine whether to grant authentication to the STA based on the information contained in the received authentication request frame. The AP can provide the result of the authentication process to the STA via an authentication response frame.

[0095] A successfully authenticated STA may perform an association process based on step S330. The association process includes a process in which the STA transmits an association request frame to the AP, and the AP transmits an association response frame to the STA in response. For example, the association request frame may include information related to various capabilities, such as a beacon listen interval, a service set identifier (SSID), supported rates, supported channels, RSN, mobility domain, supported operating classes, a Traffic Indication Map Broadcast request, and interworking service capabilities. For example, the association response frame may contain information related to various capabilities, status codes, Association ID (AID), supported rates, Enhanced Distributed Channel Access (EDCA) parameter sets, Received Channel Power Indicator (RCPI), Received Signal to Noise Indicator (RSNI), mobility domains, timeout interval (association comeback time), overlapping BSS scan parameters, TIM broadcast response, QoS maps, etc.

[0096] In step S340, the STA may perform a security setup process. The security setup process of step S340 may include, for example, a process of setting up a private key through a four-way handshaking using an Extensible Authentication Protocol over LAN (EAPOL) frame.

[0097] Figure 4 illustrates one embodiment of a multi-link (ML).

[0098] As illustrated in FIG. 4, multiple multi-link devices (MLDs) can communicate over a remote link. The MLDs can be categorized into AP MLDs including multiple AP STAs and non-AP MLDs including multiple non-AP STAs. That is, the AP MLD can include affiliated APs (i.e., AP STAs), and the non-AP MLD can include affiliated STAs (i.e., non-AP STAs, or user-STAs).

[0099] A multilink may include a first link and a second link, and different channels / subchannels / frequency resources may be allocated to the first and second links. The first and second multilinks may be identified through a link ID of 4 bits (or other n bits). The first and second links may be configured in the same 2.4 GHz, 5 GHz, or 6 GHz band. Alternatively, the first link and the second link may be configured in different bands.

[0100] The AP MLD of FIG. 4 includes three affiliated APs. In the example of FIG. 4, AP1 may operate in the 2.4 GHz band, AP2 may operate in the 5 GHz band, and AP3 may operate in the 6 GHz band. In the example of FIG. 4, the first link in which AP1 and non-AP1 operate may be defined as a channel / subchannel / frequency resource within the 2.4 GHz band. Furthermore, in the example of FIG. 4, the second link in which AP2 and non-AP2 operate may be defined as a channel / subchannel / frequency resource within the 5 GHz band. Furthermore, in the example of FIG. 4, the third link in which AP3 and non-AP3 operate may be defined as a channel / subchannel / frequency resource within the 6 GHz band.

[0101] In the example of FIG. 4, AP1 may initiate a multi-link setup procedure (ML setup procedure) by transmitting an Association Request frame to non-AP STA1. In the example of FIG. 4, non-AP STA1 may transmit an Association Response frame in response to the Association Request frame. Each AP (e.g., AP1 / 2 / 3) illustrated in FIG. 4 may be identical to the AP illustrated in FIG. 1 and / or FIG. 2, and each non-AP (e.g., non-AP1 / 2 / 3) illustrated in FIG. 4 may be identical to the STA (i.e., user-STA or non-AP STA) illustrated in FIG. 1 and / or FIG. 2.

[0102] The specific features of this specification are not limited to the specific features of FIG. 4. That is, the number of links can be defined in various ways, and multiple links can be defined in various ways within at least one band.

[0103] FIG. 5 illustrates a PPDU (physical protocol data unit or physical layer (PHY) protocol data unit) transmitted / received by an STA of this specification.

[0104] The STA (e.g., AP STA, non-AP STA, AP MLD, non-AP MLD) of the present specification can transmit and / or receive the PPDU of FIG. 5. The PPDU described in the present specification may have, for example, the structure of FIG. 5. In addition, the PPDU described in the present specification may be called by various names such as a transmission PPDU, a reception PPDU, a first type PPDU, or an Nth type PPDU, etc. The PPDU described in the present specification can be used in a WLAN system defined according to IEEE 802.11bn and / or a next-generation WLAN system that improves IEEE 802.11bn.

[0105] The PPDU of FIG. 5 may be related to various PPDU types used in a UHR system. For example, the example of FIG. 5 may be used for at least one of a single-user (SU) mode / type / transmission, a multi-user (MU) mode / type / transmission, and a null data packet (NDP) mode / type / transmission related to channel sounding. For example, if the example of FIG. 5 is related to NDP, the Data field illustrated may be omitted. If the PPDU of FIG. 5 is used for a trigger-based (TB) mode, the UHR-SIG of FIG. 5 may be omitted. In other words, an STA that has received a trigger frame for UL-MU (Uplink-MU) communication may transmit a PPDU with the UHR-SIG omitted in the example of FIG. 5.

[0106] In FIG. 5, L-STF or UHR-LTF may be called a preamble or physical preamble, and may be generated / transmitted / received / acquired / decoded in the physical layer (included in the transmitting / receiving STA).

[0107] Each block illustrated in Fig. 5 may be called a field / subfield / signal, etc. The names of these fields / subfields / signals may be, as illustrated in Fig. 5, L-STF (legacy short training field), L-LTF (legacy long training field), L-SIG (legacy signal), RL-SIG (repeated L-SIG), U-SIG (Universal Signal), UHR-SIG (UHR-signal), etc.

[0108] The subcarrier spacing of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG fields in FIG. 5 may be set to 312.5 kHz, and the subcarrier spacing of the UHR-STF, UHR-LTF, and Data fields may be set to 78.125 kHz. That is, the tone index (or subcarrier index) of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG fields may be expressed in units of 312.5 kHz, and the tone index (or subcarrier index) of the UHR-STF, UHR-LTF, and Data fields may be expressed in units of 78.125 kHz.

[0109] In the PPDU of Fig. 5, L-LTF and L-STF may be identical to conventional fields (e.g., non-HT LTF and non-HT STF defined in conventional WLAN standards).

[0110] The L-SIG field of FIG. 5 may include, for example, 24 bits of bit information. For example, the 24 bits of information may include a 4 bit Rate field, a 1 bit Reserved bit, a 12 bit Length field, a 1 bit Parity bit, and a 6 bit Tail bit. For example, the 12 bit Length field may include information about the length or time duration of the PPDU. For example, the value of the 12 bit Length field may be determined based on the type of the PPDU. For example, if the PPDU is a non-HT (non-High Throughput), HT (High Throughput), VHT (Very High Throughput) PPDU, or an EHT (extremely high throughput) PPDU or UHR PPDU, the value of the Length field may be determined as a multiple of 3. For example, if the PPDU is a HE PPDU, the value of the Length field may be determined as "a multiple of 3 + 1" or "a multiple of 3 + 2". In other words, for non-HT, HT, VHT PPDU, EHT PPDU, UHR PPDU, the value of the Length field can be determined as a multiple of 3, and for HE (High-Efficiency) PPDU, the value of the Length field can be determined as "a multiple of 3 + 1" or "a multiple of 3 + 2". In other words, the Length field in an UHR PPDU is set to a value satisfying the condition that the remainder is zero when LENGTH is divided by 3.

[0111] For example, (non-AP and AP) STAs can apply BCC encoding based on a code rate of 1 / 2 to the 24 bits of information in the L-SIG field. Then, the transmitting STA can obtain 48 BCC coded bits. BPSK modulation can be applied to the 48 coded bits to generate 48 BPSK symbols. The transmitting STA can map the 48 BPSK symbols to positions excluding the pilot subcarriers {subcarrier index -21, -7, +7, +21} and the DC subcarrier {subcarrier index 0}. As a result, the 48 BPSK symbols can be mapped to subcarrier indices -26 to -22, -20 to -8, -6 to -1, +1 to +6, +8 to +20, and +22 to +26. The transmitting STA can additionally map the signal {-1, -1, -1, 1} to the subcarrier indices {-28, -27, +27, +28}. The above signal can be used for channel estimation for the frequency domain corresponding to {-28, -27, +27, +28}.

[0112] For example, (non-AP and AP) STA can generate RL-SIG, which is generated in the same manner as L-SIG. BPSK modulation can be applied to RL-SIG. Receiving (non-AP and AP) STA can determine whether the received PPDU is a HE PPDU, EHT PPDU, or UHR PPDU based on the presence of RL-SIG. In other words, if RL-SIG is present, receiving (non-AP and AP) STA can determine whether the received PPDU is one of HE PPDU, EHT PPDU, or UHR PPDU. In other words, if RL-SIG is not present, receiving (non-AP and AP) STA can determine whether the received PPDU is one of non-HT PPDU, HT PPDU, or VHT PPDU. In other words, the RL-SIG field is a repeat of the L-SIG field and is used to differentiate an UHR PPDU from a non-HT PPDU, HT PPDU, and VHT PPDU.

[0113] After the RL-SIG in Fig. 5, a U-SIG (Universal SIG) may be inserted. The U-SIG may be called by various names such as the first SIG field, the first SIG, the first type SIG, the control signal, the control signal field, the first (type) control signal, the common control field, and the common control signal.

[0114] A U-SIG can contain N bits of information and can include information for identifying the type of EHT PPDU. For example, a U-SIG can be formed based on two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., an OFDM symbol) for a U-SIG can have a duration of 4 microseconds. Each symbol of a U-SIG can be used to transmit 26 bits of information. For example, each symbol of a U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0115] For example, A bit information (e.g., 52 uncoded bits) can be transmitted through U-SIG, and the first symbol of U-SIG can transmit the first X bits of information (e.g., 26 uncoded bits) out of the total A bit information, and the second symbol of U-SIG can transmit the remaining Y bits of information (e.g., 26 uncoded bits) out of the total A bit information. For example, the transmitting STA can obtain 26 uncoded bits included in each U-SIG symbol. The transmitting STA can perform convolutional encoding (i.e., BCC encoding) based on a rate of R=1 / 2 to generate 52 coded bits, and perform interleaving on the 52 coded bits. The transmitting STA can perform BPSK modulation on the interleaved 52 coded bits to generate 52 BPSK symbols allocated to each U-SIG symbol. A single U-SIG symbol can be transmitted based on 56 tones (subcarriers) from subcarrier index -28 to subcarrier index +28, excluding DC index 0. The 52 BPSK symbols generated by the transmitting STA can be transmitted based on the remaining tones (subcarriers) excluding the pilot tones -21, -7, +7, and +21.

[0116] For example, A bit information (e.g., 52 uncoded bits) transmitted by U-SIG may include a CRC field (e.g., a 4-bit long field) and a tail field (e.g., a 6-bit long field). The CRC field and the tail field may be transmitted through the second symbol of the U-SIG. The CRC field may be generated based on 26 bits allocated to the first symbol of the U-SIG and the remaining 16 bits excluding the CRC / tail field within the second symbol, and may be generated based on a conventional CRC calculation algorithm. In addition, the tail field may be used to terminate the trellis of the convolutional decoder and may be set to, for example, "000000".

[0117] The A bit information (e.g., 52 uncoded bits) transmitted by the U-SIG (or U-SIG field) can be divided into version-independent bits and version-dependent bits. For example, the size of the version-independent bits can be fixed or variable. For example, the version-independent bits can be assigned only to the first symbol of the U-SIG, or the version-independent bits can be assigned to both the first symbol and the second symbol of the U-SIG. For example, the version-independent bits and the version-dependent bits can be called by various names, such as the first control bit and the second control bit.

[0118] For example, the version-independent bits of the U-SIG may include a 3-bit PHY version identifier. For example, the 3-bit PHY version identifier may include information related to the PHY version of the transmitted and received PPDU. For example, a first value (e.g., a value of 000) of the 3-bit PHY version identifier may indicate that the transmitted and received PPDU is an EHT PPDU. In addition, a second value (e.g., a value of 001) of the 3-bit PHY version identifier may indicate that the transmitted and received PPDU is an UHR PPDU.

[0119] In other words, when the (AP / non-AP) STA transmits an EHT PPDU, it can set the 3-bit PHY version identifier to the first value. In other words, the receiving (AP / non-AP) STA can determine that the received PPDU is an EHT PPDU based on the PHY version identifier having the first value, and can determine that the received PPDU is an UHR PPDU based on the PHY version identifier having the second value.

[0120] For example, the version-independent bits of U-SIG may include a 1-bit UL / DL flag field. The first value of the 1-bit UL / DL flag field relates to UL communication, and the second value of the UL / DL flag field relates to DL communication.

[0121] For example, the version-independent bits of U-SIG may include information about the length of a transmission opportunity (TXOP) and information about the BSS color ID.

[0122] For example, if a UHR PPDU is classified into various types (e.g., a type related to SU transmission (performed based on UL or DL), a type related to DL transmission, a type related to NDP transmission, a type related to DL non-MU-MIMO, a type related to DL MU-MIMO, a type related to Multi-AP operation, a type related to CBF (Coordinated beamforming), SR (Spatial Reuse), a type related to C-OFDMA (Coordinated OFDMA), a type related to C-TDMA (Coordinated TDMA)), information about the type of the EHT PPDU (e.g., 2-bit or 3-bit information) can be included in the version-dependent bits of the U-SIG.

[0123] For example, a U-SIG may include information about 1) a bandwidth field including information about a bandwidth, 2) a field including information about an MCS technique applied to the UHR-SIG, 3) an indication field including information about whether a dual subcarrier modulation (DCM) technique is applied to the UHR-SIG, 4) a field including information about the number of symbols used for the UHR-SIG, 5) a field including information about whether the UHR-SIG is generated over the entire band, 6) a field including information about the type of UHR-LTF / STF, and 7) a field indicating the length of the UHR-LTF and the CP length.

[0124] Preamble puncturing may be applied to the PPDU of FIG. 5. Preamble puncturing refers to applying puncturing to a portion of the entire bandwidth of the PPDU (e.g., the secondary 20 MHz band). For example, when an 80 MHz PPDU is transmitted, the STA applies puncturing to the secondary 20 MHz band within the 80 MHz band, and can transmit the PPDU only through the primary 20 MHz band and the secondary 40 MHz band.

[0125] For example, the pattern of preamble puncturing can be preset. For example, when the first puncturing pattern is applied, puncturing can be applied only to the secondary 20 MHz band within the 80 MHz band. For example, when the second puncturing pattern is applied, puncturing can be applied only to one of the two secondary 20 MHz bands included in the secondary 40 MHz band within the 80 MHz band. For example, when the third puncturing pattern is applied, puncturing can be applied only to the secondary 20 MHz band included in the primary 80 MHz band within the 160 MHz band (or 80+80 MHz band). For example, when the fourth puncturing pattern is applied, a primary 40 MHz band included in the primary 80 MHz band within the 160 MHz band (or 80+80 MHz band) may be present, and puncturing may be applied to at least one 20 MHz channel that does not belong to the primary 40 MHz band.

[0126] Information regarding preamble puncturing applied to the PPDU may be included in the U-SIG and / or UHR-SIG. For example, the first field of the U-SIG may include information regarding the contiguous bandwidth of the PPDU, and the second field of the U-SIG may include information regarding preamble puncturing applied to the PPDU.

[0127] For example, U-SIG and UHR-SIG may include information regarding preamble puncturing based on the following method. If the bandwidth of the PPDU exceeds 80 MHz, the U-SIG may be individually configured in units of 80 MHz. For example, if the bandwidth of the PPDU is 160 MHz, the PPDU may include a first U-SIG for the first 80 MHz band and a second U-SIG for the second 80 MHz band. In this case, the first field of the first U-SIG may include information regarding the 160 MHz bandwidth, and the second field of the first U-SIG may include information regarding preamble puncturing applied to the first 80 MHz band (i.e., information regarding the preamble puncturing pattern). Additionally, the first field of the second U-SIG may include information about a 160 MHz bandwidth, and the second field of the second U-SIG may include information about preamble puncturing applied to the second 80 MHz band (i.e., information about a preamble puncturing pattern). Meanwhile, the UHR-SIG consecutive to the first U-SIG may include information about preamble puncturing applied to the second 80 MHz band (i.e., information about a preamble puncturing pattern), and the UHR-SIG consecutive to the second U-SIG may include information about preamble puncturing applied to the first 80 MHz band (i.e., information about a preamble puncturing pattern).

[0128] Additionally or alternatively, U-SIG and UHR-SIG may include information regarding preamble puncturing based on the following methods. U-SIG may include information regarding preamble puncturing for all bands (i.e., information regarding preamble puncturing patterns). That is, UHR-SIG may not include information regarding preamble puncturing, and only U-SIG may include information regarding preamble puncturing (i.e., information regarding preamble puncturing patterns).

[0129] U-SIGs can be configured in 20 MHz units. For example, if an 80 MHz PPDU is configured, U-SIGs can be duplicated. That is, four identical U-SIGs can be included within an 80 MHz PPDU. PPDUs exceeding the 80 MHz bandwidth can contain different U-SIGs.

[0130] The UHR-SIG of FIG. 5 may include control information for a receiving STA. The UHR-SIG may be transmitted via at least one symbol, and each symbol may have a length of 4 us. Information regarding the number of symbols used for the UHR-SIG may be included in the U-SIG.

[0131] UHR-SIG provides additional signals to the U-SIG field to enable STAs to interpret / decode UHR PPDUs. The UHR-SIG field may contain U-SIG overflow bits that are common to all users. The UHR-SIG field also contains resource allocation information, allowing STAs to look up resources used in fields containing data fields / UHR-STF / UHR-LTF (i.e., UHR modulated fields of an UHR PPDU).

[0132] The frequency resources of the UHR-LTF, UHR-STF, and data fields illustrated in FIG. 5 can be determined based on RUs (resource units) defined by multiple subcarriers / tones. That is, the UHR-LTF, UHR-STF, and data fields of this specification can be transmitted / received through RUs (resource units) defined by multiple subcarriers / tones.

[0133] FIG. 6 is a diagram illustrating the layout of resource units (RUs) used for a 20 MHz PPDU. That is, the UHR-LTF, UHR-STF, and / or data fields included in the 20 MHz PPDU can be transmitted / received through at least one of the various RUs defined in FIG. 6.

[0134] As shown at the top of Fig. 6, 26 units (i.e., units corresponding to 26 tones) can be arranged. Six tones can be used as a guard band in the leftmost band of the 20 MHz band, and five tones can be used as a guard band in the rightmost band of the 20 MHz band. In addition, seven DC tones can be inserted in the center band, i.e., the DC band, and 26 units corresponding to 13 tones can exist on each side of the DC band. In addition, 26 units, 52 units, and 106 units can be allocated to other bands. Each unit can be allocated for a receiving station, i.e., a user.

[0135] Meanwhile, the RU arrangement of FIG. 6 is utilized not only in a situation for multiple users (MUs) but also in a situation for a single user (SU), in which case it is possible to use one 242-unit as shown at the bottom of FIG. 4, in which case three DC tones can be inserted.

[0136] In the example of Fig. 6, RUs of various sizes, such as 26-RU, 52-RU, 106-RU, and 242-RU, are proposed. Since the specific sizes of these RUs can be expanded or increased, the present embodiment is not limited to the specific size of each RU (i.e., the number of corresponding tones). In this specification, N-RU may be represented as N-tone RU, etc. For example, 26-RU may be represented as 26-tone RU.

[0137] Figure 7 is a diagram showing the layout of resource units (RUs) used for 40MHz PPDU.

[0138] As in the example of Fig. 6 where RUs of various sizes were used, the example of Fig. 7 can also use 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, etc. In addition, 5 DC tones can be inserted at the center frequency, 12 tones can be used as a guard band in the leftmost band of the 40 MHz band, and 11 tones can be used as a guard band in the rightmost band of the 40 MHz band.

[0139] Additionally, as illustrated, 484 RUs may be used when used for a single user. Meanwhile, the specific number of RUs may be changed, as in the example of FIG. 6.

[0140] Figure 8 is a diagram illustrating the layout of resource units (RUs) used for an 80MHz PPDU. The layout of resource units (RUs) used in this specification may vary. For example, the layout of resource units (RUs) used in the 80MHz band may vary.

[0141] Figure 9 illustrates an operation according to UL-MU. As illustrated, a transmitting STA (e.g., AP) can perform channel access through contending (i.e., backoff operation) and transmit a trigger frame (930). That is, the transmitting STA (e.g., AP) can transmit a PPDU including a trigger frame (930). When a PPDU including a trigger frame is received, a TB (trigger-based) PPDU is transmitted after a delay of SIFS.

[0142] TB PPDUs (941, 942) are transmitted at the same time and can be transmitted from multiple STAs (e.g., User STAs) whose AIDs are indicated in the Trigger frame (930). The ACK frame (950) for the TB PPDU can be implemented in various forms.

[0143] Figure 10 shows an example of channels used / supported / defined within the 2.4 GHz band.

[0144] The 2.4 GHz band may be referred to by other names, such as the first band (band). Furthermore, the 2.4 GHz band may refer to a frequency range in which channels with a center frequency adjacent to 2.4 GHz (e.g., channels with a center frequency between 2.4 and 2.5 GHz) are used / supported / defined.

[0145] The 2.4 GHz band may include multiple 20 MHz channels. The 20 MHz within the 2.4 GHz band may have multiple channel indices (e.g., indices 1 through 14). For example, the center frequency of a 20 MHz channel assigned channel index 1 may be 2.412 GHz, the center frequency of a 20 MHz channel assigned channel index 2 may be 2.417 GHz, and the center frequency of a 20 MHz channel assigned channel index N may be (2.407 + 0.005*N) GHz. The channel indices may be referred to by various names, such as channel numbers. The specific numerical values ​​of the channel indices and center frequencies may change.

[0146] Figure 10 exemplarily illustrates four channels within the 2.4 GHz band. The illustrated first frequency region (1010) to fourth frequency region (1040) may each include one channel. For example, the first frequency region (1010) may include channel 1 (a 20 MHz channel having an index of 1). In this case, the center frequency of channel 1 may be set to 2412 MHz. The second frequency region (1020) may include channel 6. In this case, the center frequency of channel 6 may be set to 2437 MHz. The third frequency region (1030) may include channel 11. In this case, the center frequency of channel 11 may be set to 2462 MHz. The fourth frequency region (1040) may include channel 14. In this case, the center frequency of channel 14 may be set to 2484 MHz.

[0147] Figure 11 illustrates an example of channels used / supported / defined within the 5 GHz band.

[0148] The 5 GHz band may be referred to by other names, such as a second band / band, etc. The 5 GHz band may refer to a frequency range in which channels with center frequencies greater than or equal to 5 GHz and less than 6 GHz (or less than 5.9 GHz) are used / supported / defined. Alternatively, the 5 GHz band may include multiple channels between 4.5 GHz and 5.5 GHz. The specific figures shown in FIG. 11 are subject to change.

[0149] Multiple channels within the 5 GHz band include Unlicensed National Information Infrastructure (UNII)-1, UNII-2, UNII-3, and ISM. UNII-1 may be referred to as UNII Low. UNII-2 may include frequency ranges called UNII Mid and UNII-2Extended. UNII-3 may be referred to as UNII-Upper.

[0150] Within the 5 GHz band, multiple channels can be configured, and the bandwidth of each channel can be variously configured, such as 20 MHz, 40 MHz, 80 MHz, or 160 MHz. For example, the 5170 MHz to 5330 MHz frequency domain / range within UNII-1 and UNII-2 can be divided into eight 20 MHz channels. The 5170 MHz to 5330 MHz frequency domain / range can be divided into four channels through a 40 MHz frequency domain. The 5170 MHz to 5330 MHz frequency domain / range can be divided into two channels through an 80 MHz frequency domain. Alternatively, the 5170 MHz to 5330 MHz frequency domain / range can be divided into one channel through a 160 MHz frequency domain.

[0151] Figure 12 illustrates an example of channels used / supported / defined within the 6 GHz band.

[0152] The 6 GHz band may also be referred to by other names, such as the third band / band. The 6 GHz band may refer to the frequency range in which channels with center frequencies above 5.9 GHz are used, supported, or defined. The specific figures shown in Figure 12 are subject to change.

[0153] For example, the 20 MHz channel of FIG. 12 can be defined from 5.940 GHz. Specifically, the leftmost channel among the 20 MHz channels of FIG. 12 can have an index of 1 (or channel index, channel number, etc.), and a center frequency of 5.945 GHz can be assigned. That is, the center frequency of the indexed channel N can be determined as (5.940 + 0.005*N) GHz.

[0154] Accordingly, the indexes (or channel numbers) of the 20 MHz channels of FIG. 12 are 1, 5, 9, 13, 17, 21, 25, 29, 33, 37, 41, 45, 49, 53, 57, 61, 65, 69, 73, 77, 81, 85, 89, 93, 97, 101, 105, 109, 113, 117, 121, 125, 129, 133, 137, 141, 145, 149, 153, 157, 161, 165, 169, 173, 177, 181, 185, 189, 193, It can be 197, 201, 205, 209, 213, 217, 221, 225, 229, 233. Also, according to the (5.940 + 0.005*N) GHz rule mentioned above, the indices of the 40 MHz channels in Fig. 12 can be 3, 11, 19, 27, 35, 43, 51, 59, 67, 75, 83, 91, 99, 107, 115, 123, 131, 139, 147, 155, 163, 171, 179, 187, 195, 203, 211, 219, 227.

[0155] Below, the structure and types / subtypes of MAC frames are described.

[0156] Fig. 13 illustrates an example of a header of a MAC frame. As illustrated, the MAC frame may include a frame control field / information of 2 octets in length, a duration field / information of 2 octets in length, a RA (Receiver Address) field / information of 6 octets in length, and a TA (Transmitter Address) field / information of 6 octets in length. As illustrated in Fig. 13, the four fields may be consecutive to each other. The MAC header of Fig. 13 may be modified in various ways, and a new field may be inserted between the four illustrated fields, or at least one of the illustrated fields may be omitted.

[0157] The MAC header illustrated in Fig. 13 may be positioned at the very front of a MAC frame. That is, the MAC frame may include a MAC header as illustrated in Fig. 13 and MAC body fields / information subsequent to the MAC header. The MAC frame including the MAC header of Fig. 13 is inserted / included in the data field of the PPDU (e.g., UHR PPDU) illustrated in Fig. 5.

[0158] The MAC frames included in the data field of the PPDU of this specification can be classified into various types. For example, the MAC frames of this specification can be classified into control frames, management frames, and data frames.

[0159] For example, the management frame includes Association Request, Association Response, Reassociation Request, Reassociation Response, Probe Request, Probe Response, Beacon, Disassociation, Authentication, and Deauthentication frames / signals defined in conventional WLAN. For the management frame, the values ​​of the type fields (B3 and B2) in FIG. 13 are set to 00. In addition, the values ​​of the subtype fields (B7, B6, B5, B4) in FIG. 13 are as follows: Association Request (0000), Association Response (0001), Reassociation Request (0010), Reassociation Response (0011), Probe Request (0100), Probe Response (0101), Beacon (1000), Disassociation (1010), Authentication (1011), Deauthentication (1100).

[0160] For example, the control frame includes Trigger Beamforming Report Poll, NDP Announcement (NDPA), Control Frame Extension, Control Wrapper, Block Ack Request (BlockAckReq), Block Ack (BlockAck), PS-Poll, RTS, CTS, Ack, and CF-End frames / signals defined in conventional WLAN. For the control frame, the value of the type field (B3 and B2) in FIG. 13 is set to 01. Also, the values ​​of the subtype fields (B7, B6, B5, B4) of FIG. 13 are as follows: Trigger (0010), Beamforming Report Poll (0100), NDP Announcement (0101), Control Frame Extension (0110), Control Wrapper (0111), BlockAckReq (1000), BlockAck (1001), PS-Poll (1010), RTS (1011), CTS (1100), Ack (1101), CF-End (1110).

[0161] For example, the data frame includes (QoS) Data, (QoS) Null, etc. defined in conventional WLAN. For the management frame, the value of the type field (B3 and B2) of Fig. 13 is set to 10.

[0162] The MAC frame / signal used in this specification can be identified through the type field / information and subtype field / information described above. For example, “frame” in this specification can mean a MAC frame in which the type bits B3 and B2 bits in the frame control field of the MAC header are set to 01, and the subtype bits B7, B6, B5, and B4 bits in the frame control field are set to 0010. Various MAC frames described in this specification are inserted / included in the data fields of various PPDUs (e.g., HE / VHT / HE / EHT / UHR PPDUs).

[0163] FIG. 14 illustrates a modified example of a transmitting device and / or a receiving device of the present specification.

[0164] The devices (e.g., AP STA, non-AP STA) illustrated in FIGS. 1 to 4 may be modified as illustrated in FIG. 14. The transceiver (630) of FIG. 14 may be identical to the transceivers (113, 123) of FIG. 1. The transceiver (630) of FIG. 14 may include a receiver and a transmitter.

[0165] The processor (610) of FIG. 14 may be identical to the processor (111, 121) of FIG. 1. Alternatively, the processor (610) of FIG. 14 may be identical to the processing chip (114, 124) of FIG. 1.

[0166] The memory (150) of FIG. 14 may be the same as the memory (112, 122) of FIG. 1. Alternatively, the memory (150) of FIG. 14 may be a separate external memory different from the memory (112, 122) of FIG. 1.

[0167] Referring to FIG. 14, a power management module (611) manages power to a processor (610) and / or a transceiver (630). A battery (612) supplies power to the power management module (611). A display (613) outputs results processed by the processor (610). A keypad (614) receives input to be used by the processor (610). The keypad (614) may be displayed on the display (613). A SIM card (615) may be an integrated circuit used to securely store an international mobile subscriber identity (IMSI) and an associated key used to identify and authenticate a subscriber in a mobile phone device, such as a mobile phone or computer.

[0168] Referring to FIG. 14, the speaker (640) can output sound-related results processed by the processor (610). The microphone (641) can receive sound-related input to be used by the processor (610).

[0169] 1. Problems with prior art (Fast BSS Transition (FT))

[0170] Figure 15 illustrates an over-the-air (OTA) FT protocol in a Robust Security Network (RSN).

[0171] Currently, in 802.11, when a non-AP STA moves (roams) from an AP (Old AP) to another AP (New AP), i.e., for a BSS (Basic Service Set) Transition, it must go through a reassociation process in the same mobility domain. A representative example is the Fast BSS Transition (FT) technology. In FT, as shown in Figure 15, several processes such as authentication and reassociation are performed with the FT Originator (FTO) and the Target FT Responder (FTR) (i.e., the New AP).

[0172] After this process, many operational parameters such as Agreement, Sequence Number (SN), EDCAF Parameter, etc. related to BlockAck (BA), Stream Classification Service (SCS), etc. are reset. Accordingly, there is an overhead that requires re-performing agreement / configuration along with multiple frame exchanges, and data loss may also occur during the FT process. Furthermore, from the perspective of a non-AP STA, seamless roaming without interruption is not easy. Therefore, this specification proposes a seamless roaming method utilizing AP MLD (Multi-Link Device) to solve this problem. Unlike FT, roaming does not require re-authentication / association.

[0173] In this specification, an STA performing BSS Transition (i.e., Roaming) is referred to as an RSTA, the AP to which the STA is currently associated when roaming is referred to as an Old AP (O_AP), and the AP to which the STA will roam is referred to as a New AP (N_AP). In addition, the Roaming method proposed in this specification is referred to as MLD Roaming. The designations (names) in this specification may be changed, and an STA may include an AP STA or a non-AP STA.

[0174] 2. UHR AP MLD structure for roaming

[0175] 2.1 General Procedure of Roaming in AP MLD

[0176] Figure 16 illustrates the high-level architecture for AP MLD.

[0177] Basically, an AP MLD can include one or more APs and has a high-level architecture as shown in Figure 16. Basically, the MLD can control several procedures / parameters common to multiple APs using the upper MAC sublayer. Examples of these procedures / parameters include authentication, association, SN / PN assignment, and power-save buffering of individually addressed frames.

[0178] Therefore, by utilizing AP MLD functionality, MLD-level parameters can be maintained without being reset when moving between APs (affiliated APs) involved in AP MLD. This specification proposes a roaming method utilizing AP MLD functionality.

[0179] Figure 17 illustrates an example of a high-level architecture for UHR AP MLD.

[0180] Figure 17 illustrates the architecture of APs supporting Seamless Roaming. To support Seamless Roaming, APs must be compatible with devices from previous standard versions and enable seamless roaming between multiple devices. First, to ensure legacy compatibility with older devices, non-UHR non-AP STAs must be able to see non-UHR APs. This requires maintaining the MLD definition itself and modifying the existing architecture. Therefore, as shown in Figure 17, we define a new UHR AP MLD that maintains the existing MLD architecture while hierarchically affiliates MLDs that support seamless roaming. Each LMAC of the AP MLDs interfaces with a UHR UMAC, and the functions of the UMAC of the AP MLD supporting seamless roaming are managed by the UHR UMAC. This architecture also addresses scalability issues caused by the limitations of the Link ID bit size. By default, the Link ID is 4 bits, supporting a maximum of 16 Link IDs. When roaming, a Link ID is required to move from one link to another. However, the existing method limits the number of APs available for roaming to 16. To address this issue, Link IDs are tied to AP MLD IDs, addressing scalability issues. This is described in more detail in Section 2.2.

[0181] Figure 18 illustrates another example of a high-level architecture for UHR AP MLD.

[0182] Figure 18 shows an example with a similar architecture to Figure 17 but with different interfacing. In Figure 18, the LMAC of the AP MLD and the UHR UMAC are not directly connected, but are interfaced to the TID-to-Link Mapping function of the UMAC. This architecture allows TID-to-Link Mapping to be performed individually in the UMAC of the AP MLD or in the UHR UMAC. The method of use of this architecture and the types and number of functions interfaced with the UHR UMAC are not limited.

[0183] Figure 19 illustrates an example of a UHR AP MLD structure for roaming.

[0184] Referring to Fig. 19, each EHT AP MLD is in a different location, i.e., non-collocated, and the APs belonging to each EHT AP MLD are in the same or similar locations, i.e., collocated. This collocated can mean belonging to the exact same physical device, or it can be expressed as 'collocated' in a logically similar location even though it does not belong to the physical device. Basically, since the AP MLD is a logical entity, it can be any physical device, but it can operate as an MLD that covers affiliated APs regardless of location and can apply multi-link operation (MLO). Ultimately, all APs belonging to each EHT AP MLD become affiliated APs of one UHR AP MLD. For example, EHT AP MLD 1 in Fig. 19 includes affiliated APs 1, 2, and 3.

[0185] Based on Figure 19, when an MLD (or STA) moves, it will typically roam from one EHT AP MLD to another. However, roaming does not necessarily only involve movement between different EHT AP MLDs. For example, roaming can also change APs within an EHT AP MLD.

[0186] Meanwhile, a moving MLD (or STA) must be able to recognize which AP within the UHR AP MLD it should roam to based on this structure. When a roaming request is made, the UHR AP MLD must be able to determine which new AP it is moving from, and whether the old AP should forward data or management information to the new AP. Therefore, identification is required for this purpose. This specification proposes an identification method that considers non-collocated affiliated APs in a UHR AP MLD.

[0187] The references (names) in this specification may change, and STA may include AP STA or non-AP STA.

[0188] 3. UHR AP MLD indicator for roaming

[0189] Basically, since roaming is possible between APs affiliated with the same UHR AP MLD, in order for a non-AP STA to know whether an AP is an AP that can roam, the currently connected AP must provide information about whether neighboring APs in the vicinity are affiliated with the same UHR AP MLD when announcing information to the non-AP STA about the neighboring APs. This specification proposes a method to convey this information through the Basic ML element and the RNR element. Through the UHR AP MLD indicator, a non-AP STA can check whether an AP is an AP that can roam before requesting roaming, thereby preventing unnecessary resource usage by not requesting information about APs that cannot roam.

[0190] 3.1 Usage of Same UHR AP MLD Indication: Announcement

[0191] Each AP in each AP MLD can announce whether roaming as proposed in this specification is possible, an indicator indicating whether it is affiliated with the same UHR AP MLD, and an EHT AP MLD ID. The relevant information is as follows and can include at least one of the following:

[0192] - MLD Roaming enabled: Indicator indicating whether roaming is enabled (e.g., indicated by 1 bit)

[0193] - Same UHR AP MLD indicator: Indicates whether the non-AP STA is affiliated with the same UHR AP MLD as the currently connected AP. (Eg, indicated by 1 bit)

[0194] The above information can be included in Management (MGMT) frames such as Beacon or Probe Response, and can be included in MLD Roaming IEs containing new MLD Roaming information or existing Reduced Neighbor Report (RNR) IEs. Figure 20 provides an example of when it can be included in RNR IEs. Basically, information can be included in the TBTT Information field for each AP.

[0195] Figure 20 illustrates an example of an RNR IE containing MLD Roaming information.

[0196] As shown in Figure 20, if the existing MLD Parameters subfield is not large enough, a new MLD Roaming Parameters subfield can be created to contain information. While the existing size can be changed, this may cause decoding issues for 802.11be STAs. In particular, in this case, MLD Roaming Enabled may not be included, as the inclusion of MLD Roaming Parameters itself may imply that MLD roaming is possible.

[0197] For example, if the bit of the Same UHR AP MLD indicator is set to 1, it means that roaming is possible because it is affiliated with the same UHR AP MLD. If the bit is set to 0, it means that roaming is not possible because it is affiliated with a different UHR AP MLD. For another example, if the bit of the Same UHR AP MLD indicator is set to 0, it means that roaming is possible because it is affiliated with the same UHR AP MLD. If the bit is set to 1, it means that roaming is not possible because it is affiliated with a different UHR AP MLD. For another example, the bit of the Same UHR AP MLD indicator can be set to various values ​​to indicate whether or not it is affiliated with the same UHR AP MLD.

[0198] This information may also be included in the Basic Multi-link IE, as it is also MLD-related. The following information is related to the Basic Multi-link IE.

[0199] 3.2 Usage of Same UHR AP MLD Indication: Request / Response

[0200] Before roaming, a non-AP MLD (STA) can request information about APs within each EHT AP MLD for roaming within the AP MLD. This can be achieved by utilizing the multi-link probe request / response used to obtain information during ML operation (MLO).

[0201] A multi-link probe request includes a Probe Request ML IE, in which the UHR AP MLD ID can be included using at least one of the following methods:

[0202] 1) If included in the Common Info field

[0203] Figure 21 illustrates an example where the Common Info field includes the Same UHR AP MLD indicator.

[0204] Referring to Figure 21, the presence bitmap of the Probe Request Multi-Link element can be used to indicate whether the Same UHR AP MLD indicator is included. If it is included only in the Common Info field, only APs in the EHT AP MLD with the Same UHR AP MLD indicator and the same AP MLD ID can be requested. In other words, requests cannot be made for multiple AP MLD IDs even within the same UHR AP MLD.

[0205] 2) If included in the Link Info field - always present

[0206] Figure 22 illustrates an example where the Link Info field includes the Same UHR AP MLD indicator (Mandatory).

[0207] The Link Info field can contain multiple Per-STA Profile subelements, each of which can indicate a request for an AP via a Link ID. The EHT AP MLD can be indicated via the AP MLD ID included in the Probe Request Multi-Link element and the AP MLD ID in the STA Control field of the Per-STA Profile subelement. This allows requesting information for multiple APs corresponding to multiple AP MLD IDs, but the overhead is greater than indicating it in the Common Info field when requesting for the same AP MLD ID.

[0208] 3) If included in the Link Info field - if not always present

[0209] Figure 23 illustrates an example where the Link Info field includes the Same UHR AP MLD indicator (Optional).

[0210] The inclusion of the Same UHR AP MLD indicator field can be indicated through the Same UHR AP MLD Indication Present in the STA Control field of the Per-STA Profile subelement, and the Same UHR AP MLD indicator can be included in the STA Info field or the STA Profile field. Similarly, this can request information about multiple APs corresponding to multiple AP MLD IDs. In particular, if combined with the indication method in the Common Info field of method 1), the overhead can be reduced compared to method 2) by not including the Same UHR AP MLD indicator when requesting only information about APs corresponding to the same AP MLD ID.

[0211] Meanwhile, if the Same UHR AP MLD indicator is included in the Common Info, it may be implicitly recognized that this is a request for information from APs corresponding to the same AP MLD, and thus the Same UHR AP MLD indicator may not be included in the Link Info field. In other words, the Same UHR AP MLD Indication Present field may not be included in the Link Info field.

[0212] A multi-link probe response contains a Basic ML IE, in which the Same UHR AP MLD indicator may be included using at least one of the following methods:

[0213] 1) If included in the Common Info field

[0214] This can be used when requested using method 1) of the multi-link probe request described above.

[0215] Similarly, the presence bitmap indicates whether the Same UHR AP MLD indicator is included, and accordingly, the Same UHR AP MLD indicator is included in the Common Info field. This can only provide information about APs belonging to the same EHT AP MLD.

[0216] 2) If included in the Link Info field - always present

[0217] This can be used when requested using method 2) of the multi-link probe request described above.

[0218] Include a Same UHR AP MLD indicator corresponding to the AP corresponding to the Link ID of each Per-STA Profile subelement in the STA Control field. This can provide information about multiple APs affiliated with multiple AP MLDs, but the overhead is greater than in method 1) when providing information about APs affiliated with the same AP MLD.

[0219] 3) If included in the Link Info field - if not always present

[0220] The Same UHR AP MLD Indication Present in the STA Control field of the Per-STA Profile subelement can indicate whether to include the Same UHR AP MLD Indication corresponding to the AP corresponding to the Link ID. The Same UHR AP MLD Indication can be included in the STA Info field or the STA Profile field. Similarly, this can provide information about multiple APs affiliated with multiple AP MLDs. In particular, if combined with the indication method in the Common Info field of method 1), the overhead can be reduced compared to method 2) by not including the Same UHR AP MLD indicator when only providing information about APs affiliated with the same AP MLD.

[0221] => Meanwhile, in the case of 3.1 Usage of Same UHR AP MLD Indication: Announcement described above, if the Same UHR AP MLD indicator is 0, the Same UHR AP MLD indicator may be omitted. That is, if the Same UHR AP MLD indicator does not exist, an STA that receives a Beacon or Probe Response can implicitly recognize that the AP is affiliated with the UHR AP MLD to which the STA itself is affiliated.

[0222] = On the other hand, if the Same UHR AP MLD indicator is included in the Common Info in another way, it may be implicitly recognized that this is information about APs corresponding to the same UHR AP MLD, and thus the Same UHR AP MLD indicator may not be included in the Link Info field. In other words, the UHR AP MLD ID Present field may not be included.

[0223] Figure 24 is an example of a multi-link probe request / response using the Same UHR AP MLD indicator.

[0224] MLD (or STA) requests information about AP 1 and AP 4 to AP 3 belonging to EHT AP MLD 1 via a multi-link probe request. At this time, since AP 1 requests Same UHR AP MLD Indication 1 and AP MLD ID 0, and AP 4 requests Same UHR AP MLD Indication 1 and AP MLD ID 1, they are requesting APs belonging to other EHT AP MLDs belonging to the same UHR AP MLD. Therefore, in the case of methods 1) and 3) of the multi-link probe request, Same UHR AP MLD Indication of Common Info does not exist or is set to 1. For reference, the Link IDs of AP 1 and AP 4 are both 0, but they can be distinguished by Same UHR AP MLD Indication and AP MLD ID.

[0225] Similarly, AP 3 provides information to AP 1 and AP 4 through multi-link probe response. For methods 1) and 3) of multi-link probe response, the Same UHR AP MLD Indication in Common Info is not present or is set to 1.

[0226] Figure 25 shows a flowchart illustrating the roaming process.

[0227] The AP's transmission and reception process is as follows.

[0228] The current AP transmits information about other APs to the STA through the Beacon. At this time, if the AP is affiliated with the same UHR AP MLD as the current AP, the Same UHR AP MLD Indication bit is set to 1. If the AP is not affiliated with the same UHR AP MLD as the current AP, the Same UHR AP MLD Indication bit is set to 0. If all APs belong to the same UHR AP MLD as the current AP, the Same UHR AP MLD Indication field can be omitted. When the AP receives the MLD Roaming Request frame from the STA, it checks the ID of the AP to which the STA wants to roam through the Link ID and AP MLD ID. The AP transmits to the STA whether it accepts the frame and the information described in the Roaming Response frame format through the MLD Roaming Response frame.

[0229] The STA transmission and reception process is as follows.

[0230] The STA receives information about other APs from the Current AP via the Beacon. The STA determines the AP to which to roam based on the information about the APs received from the Current AP. At this time, the request is made only for APs that do not include the Same UHR AP MLD Indication bit or have it set to 1. The STA transmits a Roaming Request frame to the Current AP. The STA receives an MLD Roaming Response frame from the Current AP and, if accepted, roams to the Target AP.

[0231] 3.3 Usage of ID Configuration: DS-STA-NOTIFY

[0232] This section refers to FIG. 19. When roaming from EHT AP MLD 1 to EHT AP MLD 2, an MLD (or STA) can basically receive data frames from APs in the currently associated EHT AP MLD 1. That is, APs in EHT AP MLD 2 cannot transmit data frames until they are associated with EHT AP MLD 2. Although it may be possible if all EHT AP MLDs in the AP MLD domain receive data frames for the corresponding MLD (or STA) from the DS, this is quite inefficient. Therefore, it may be considered to receive data frames from APs in EHT AP MLD 1 until roaming is triggered. Therefore, at this time, if roaming is triggered, a method is needed to also receive data frames from APs in EHT AP MLD 2 to which roaming will occur.

[0233] Basically, the Distributed System (DS) maps which STA is associated with which EHT AP MLD through the DS-STA-NOTIFY.request from the UHR AP MLD. Through this, the data is forwarded to the EHT AP MLD with which the MLD (or STA) is associated.

[0234] Figure 26 illustrates an example of primitive parameters of DS-STA-NOTIFY.request.

[0235] Therefore, in order to transmit data to each AP in the EHT AP MLD located in multiple locations within the UHR AP MLD, the AP MLD ID can be added to the primitive parameters of the DS-STA-NOTIFY.request. In other words, the MLD (or STA) data is transmitted from the DS only to the APs in the EHT AP MLD mapped with the AP MLD ID in the AP MLD.

[0236] This can be done by configuring the primitive parameters of the DS-STA-NOTIFY.request in the following way:

[0237] - AP MLD ID List as an additional parameter: DS can transmit data to APs in the EHT AP MLD corresponding to the listed EHT AP MLD ID.

[0238] - Newly configure Temporary DS-STA-NOTIFY.request: Add a new Temporary DS-STA-NOTIFY.request so that the EHT AP MLD to be roamed can temporarily receive data from the DS until it associates with the APs. The DS-STA-NOTIFY.request and Temporary DS-STA-NOTIFY.request configuration add the AP MLD ID to the existing primitive parameters.

[0239] To update this mapping, the MLD (or STA) can request at least one of the following pieces of information from the AP of the EHT AP MLD (AP of EHT AP MLD 1 in FIG. 19) before roaming or the AP of the EHT AP MLD to which it will roam (AP of EHT AP MLD 2 in FIG. 19). This information can be transmitted by being included in a Management (Action) frame, etc.

[0240] - Additional DS-STA-NOTIFY indication: Requests additional data transmission to the EHT AP MLD that will be roaming via DS.

[0241] - AP MLD ID: Indicates the AP MLD ID for which DS-STA-NOTIFY will be updated using the method presented above. There may be at least one AP MLD ID or more than one.

[0242] Fig. 27 is a flowchart illustrating the operation of a transmitting device according to the present embodiment.

[0243] An example of FIG. 27 may be performed at a transmitting STA or transmitting device (AP and / or non-AP STA).

[0244] Some of the steps (or detailed sub-steps described below) in the example of Fig. 27 may be omitted or changed.

[0245] Through step S2710, the transmitting device (transmitting STA) can obtain information regarding the aforementioned Tone Plan. As described above, the information regarding the Tone Plan includes the size and location of the RU, control information related to the RU, information regarding the frequency band in which the RU is included, information regarding the STA receiving the RU, etc.

[0246] Through step S2720, the transmitting device can configure / generate a PPDU based on the acquired control information. The step of configuring / generating the PPDU may include a step of configuring / generating each field of the PPDU. That is, step S2720 may include a step of configuring an EHT-SIG field including control information regarding a Tone Plan. That is, step S2720 may include a step of configuring a field including control information indicating the size / position of an RU (e.g., an N bitmap) and / or a step of configuring a field including an identifier (e.g., an AID) of an STA receiving the RU.

[0247] Additionally, step S2720 may include a step of generating an STF / LTF sequence to be transmitted through a specific RU. The STF / LTF sequence may be generated based on a preset STF generation sequence / LTF generation sequence.

[0248] Additionally, step S2720 may include a step of generating a data field (i.e., MPDU) to be transmitted via a specific RU.

[0249] The transmitting device can transmit the PPDU configured through step S2720 to the receiving device based on step S2730.

[0250] While performing step S2730, the transmitting device may perform at least one of operations such as CSD, Spatial Mapping, IDFT / IFFT operation, and GI insertion.

[0251] A signal / field / sequence configured according to this specification can be transmitted in the form of FIG. 5.

[0252] Fig. 28 is a flowchart illustrating the operation of a receiving device according to the present embodiment.

[0253] The above-described PPDU can be received according to an example of FIG. 28.

[0254] An example of FIG. 28 may be performed at a receiving STA or receiving device (AP and / or non-AP STA).

[0255] Some of the steps (or detailed sub-steps described below) in the example of Fig. 28 may be omitted.

[0256] A receiving device (receiving STA) may receive all or part of a PPDU through step S2810. The received signal may have the form of FIG. 5.

[0257] The sub-step of step S2810 can be determined based on step S2730 of Fig. 27. That is, step S2810 can perform an operation to restore the results of the CSD, Spatial Mapping, IDFT / IFFT operations, and GI insert operations applied in step S2730.

[0258] At step S2820, the receiving device can decode all or part of the PPDU. Additionally, the receiving device can obtain control information related to the Tone Plan (i.e., RU) from the decoded PPDU.

[0259] More specifically, the receiving device can decode the L-SIG and EHT-SIG of the PPDU based on the Legacy STF / LTF and obtain information included in the L-SIG and EHT SIG fields. Information regarding various Tone Plans (i.e., RUs) described herein can be included in the EHT-SIG, and the receiving STA can obtain information regarding the Tone Plan (i.e., RU) through the EHT-SIG.

[0260] In step S2830, the receiving device can decode the remaining portion of the PPDU based on the information about the Tone Plan (i.e., RU) acquired through step S2820. For example, the receiving STA can decode the STF / LTF field of the PPDU based on the information about one Plan (i.e., RU). In addition, the receiving STA can decode the data field of the PPDU based on the information about the Tone Plan (i.e., RU) and acquire the MPDU included in the data field.

[0261] Additionally, the receiving device may perform a processing operation to transmit the decoded data to a higher layer (e.g., MAC layer) through step S2830. Additionally, if the generation of a signal is instructed from the higher layer to the PHY layer in response to the data transmitted to the higher layer, a subsequent operation may be performed.

[0262] Hereinafter, the above-described embodiment will be described with reference to FIGS. 1 to 28.

[0263] Fig. 29 is a flowchart illustrating a procedure for performing MLD roaming by checking whether an AP according to the present embodiment is an AP capable of roaming.

[0264] An example of FIG. 29 can be performed in a network environment that supports a next-generation wireless LAN system (UHR (Ultra High Reliability) wireless LAN system or next wi-fi). The next-generation wireless LAN system is a wireless LAN system that improves on the 802.11be system and can satisfy backward compatibility with the 802.11be system.

[0265] An example of FIG. 29 is performed at a transmitting STA, which may correspond to an access point (AP). The receiving STA of FIG. 29 may correspond to at least one STA (station).

[0266] The present embodiment proposes a method for notifying a non-AP MLD (or non-AP STA) when roaming to another AP whether the other AP belongs to the same mobility domain or the same roaming-enabled group. In particular, the present embodiment has the effect of enabling seamless roaming without re-authentication and re-association with the AP to which the STA is trying to roam by notifying in advance through a management frame whether the other AP is capable of roaming.

[0267] In step S2910, the first AP (access point) transmits a management frame to the first non-AP STA (station).

[0268] At step S2920, the first AP determines roaming from the first AP to the second AP based on the management frame.

[0269] The first AP is affiliated with the first AP MLD (multi-link device), and the second AP is affiliated with the second AP MLD. Since the first and second APs are affiliated with different AP MLDs, the AP MLD IDs of the first and second APs may be set to different values.

[0270] The above management frame includes first information on whether the second AP is included in the same roaming-enabled group as the first AP. The first information may be referred to as a Same UHR AP MLD indicator.

[0271] Based on the first information being set to 1, the second AP is included in the same roaming-enabled group as the first AP. Based on the first information being set to 0, the second AP is not included in the same roaming-enabled group as the first AP (i.e., the second AP is included in a different roaming-enabled group than the first AP).

[0272] The first AP may be referred to as an Old AP (O_AP), a Serving AP, or a Current AP. The second AP may be referred to as a New AP (N_AP) or a Target AP. The first AP MLD including the first AP may be referred to as a Serving AP MLD. The second AP MLD including the second AP may be referred to as a Target AP MLD.

[0273] The above roaming-enabled group may be referred to as a UHR AP MLD. The first and second AP MLDs are non-collocated, but are included in the same roaming-enabled group, so roaming (or movement) from an AP in the first AP MLD to an AP in the second AP MLD may be possible. The APs in the first AP MLD are collocated. The APs in the second AP MLD are also collocated.

[0274] That is, the present embodiment has the effect of preventing unnecessary resource use by including the first information (UHR AP MLD Indication) in the management frame so that a non-AP STA can check whether the AP is roamable before requesting roaming, thereby preventing requests for information about APs that are not roamable. In addition, it has the effect of resolving packet loss and delay and enabling seamless movement to another AP.

[0275] The above management frame may be a beacon or probe response frame.

[0276] The above first information may be included in the TBTT (Target Beacon Transmission Time) information field of the RNR (Reduced Neighbor Report) IE (Information Element) of the beacon or probe response frame.

[0277] The AP may receive a request frame from the first non-AP STA. The AP may transmit a response frame to the first non-AP STA. (Alternatively, the first non-AP STA may transmit a request frame to the first AP. The first non-AP STA may receive a response frame from the first AP.)

[0278] The request frame may include a first presence bitmap subfield and a first common information field. The first presence bitmap subfield may include second information indicating the presence of the first information. Whether the first information is included in the first common information field may be determined based on the value of the second information.

[0279] The above request frame may further include a first link information field.

[0280] For example, the first information may be included in the STA control field of the first link information field.

[0281] As another example, the first link information field may include a STA control field and a STA information field. The STA control field may include the second information. Whether the first information is included in the STA information field may be determined based on the value of the second information.

[0282] As another example, if the first common information field includes the first information, it can be implicitly recognized that this is an information request from APs corresponding to the same AP MLD, and therefore the first and second information may not be included in the first link information field.

[0283] The response frame may include a second presence bitmap subfield and a second common information field. The second presence bitmap subfield may include the second information indicating the presence of the first information. Whether the first information is included in the second common information field may be determined based on the value of the second information.

[0284] The above response frame may further include a second link information field.

[0285] For example, the first information may be included in the STA control field of the second link information field.

[0286] As another example, the second link information field may include a STA control field and a STA information field. The STA control field may include the second information. Whether the first information is included in the STA information field may be determined based on the value of the second information.

[0287] When roaming is determined from the first AP to the second AP, the first AP may receive an MLD roaming request frame from the first non-AP STA. The first AP may transmit an MLD roaming response frame to the first non-AP STA. The first non-AP STA may perform roaming from the first AP to the second AP based on the MLD roaming request frame and the MLD roaming response frame. (Alternatively, the first non-AP STA may transmit an MLD roaming request frame to the first AP. The first non-AP STA may receive an MLD roaming response frame from the first AP. The first AP may perform roaming from the first AP to the second AP based on the MLD roaming request frame and the MLD roaming response frame.)

[0288] The above MLD roaming request frame may be defined based on a Reconfiguration Multi-link Information Element (IE). The common information field of the MLD roaming request frame may include an identifier of the second AP MLD and an identifier of the group in which roaming is possible. The link information field of the MLD roaming request frame may include link identifiers of the first and second APs, an identifier of the second AP MLD, and an identifier of the group in which roaming is possible.

[0289] The above MLD roaming response frame may be defined based on the Basic Multi-link IE. The common information field of the MLD roaming response frame may include the identifier of the second AP MLD and the identifier of the group in which roaming is possible. The link information field of the MLD roaming response frame may include the link identifier of the second AP, the identifier of the second AP MLD, and the identifier of the group in which roaming is possible.

[0290] After roaming from the first AP to the second AP is completed, the first non-AP STA can receive the DL (downlink) data from the second AP.

[0291] Figure 30 is a flowchart illustrating a procedure for performing MLD roaming by checking whether an STA according to the present embodiment is an AP capable of roaming.

[0292] An example of FIG. 30 can be performed in a network environment that supports a next-generation wireless LAN system (UHR (Ultra High Reliability) wireless LAN system or next wi-fi). The next-generation wireless LAN system is a wireless LAN system that improves on the 802.11be system and can satisfy backward compatibility with the 802.11be system.

[0293] An example of FIG. 30 is performed at a receiving STA, and the receiving STA may correspond to at least one STA (station). The transmitting STA of FIG. 30 may correspond to an AP (access point).

[0294] The present embodiment proposes a method for notifying a non-AP MLD (or non-AP STA) when roaming to another AP whether the other AP belongs to the same mobility domain or the same roaming-enabled group. In particular, the present embodiment has the effect of enabling seamless roaming without re-authentication and re-association with the AP to which the STA is trying to roam by notifying in advance through a management frame whether the other AP is capable of roaming.

[0295] In step S3010, the first non-AP STA (non-access point station) receives a management frame from the first AP.

[0296] In step S3020, the first non-AP STA decides to roam from the first AP to the second AP based on the management frame.

[0297] The first AP is affiliated with the first AP MLD (multi-link device), and the second AP is affiliated with the second AP MLD. Since the first and second APs are affiliated with different AP MLDs, the AP MLD IDs of the first and second APs may be set to different values.

[0298] The above management frame includes first information on whether the second AP is included in the same roaming-enabled group as the first AP. The first information may be referred to as a Same UHR AP MLD indicator.

[0299] Based on the first information being set to 1, the second AP is included in the same roaming-enabled group as the first AP. Based on the first information being set to 0, the second AP is not included in the same roaming-enabled group as the first AP (i.e., the second AP is included in a different roaming-enabled group than the first AP).

[0300] The first AP may be referred to as an Old AP (O_AP), a Serving AP, or a Current AP. The second AP may be referred to as a New AP (N_AP) or a Target AP. The first AP MLD including the first AP may be referred to as a Serving AP MLD. The second AP MLD including the second AP may be referred to as a Target AP MLD.

[0301] The above roaming-enabled group may be referred to as a UHR AP MLD. The first and second AP MLDs are non-collocated, but are included in the same roaming-enabled group, so roaming (or movement) from an AP in the first AP MLD to an AP in the second AP MLD may be possible. The APs in the first AP MLD are collocated. The APs in the second AP MLD are also collocated.

[0302] That is, the present embodiment has the effect of preventing unnecessary resource use by including the first information (UHR AP MLD Indication) in the management frame so that a non-AP STA can check whether the AP is roamable before requesting roaming, thereby preventing requests for information about APs that are not roamable. In addition, it has the effect of resolving packet loss and delay and enabling seamless movement to another AP.

[0303] The above management frame may be a beacon or probe response frame.

[0304] The above first information may be included in the TBTT (Target Beacon Transmission Time) information field of the RNR (Reduced Neighbor Report) IE (Information Element) of the beacon or probe response frame.

[0305] The AP may receive a request frame from the first non-AP STA. The AP may transmit a response frame to the first non-AP STA. (Alternatively, the first non-AP STA may transmit a request frame to the first AP. The first non-AP STA may receive a response frame from the first AP.)

[0306] The request frame may include a first presence bitmap subfield and a first common information field. The first presence bitmap subfield may include second information indicating the presence of the first information. Whether the first information is included in the first common information field may be determined based on the value of the second information.

[0307] The above request frame may further include a first link information field.

[0308] For example, the first information may be included in the STA control field of the first link information field.

[0309] As another example, the first link information field may include a STA control field and a STA information field. The STA control field may include the second information. Whether the first information is included in the STA information field may be determined based on the value of the second information.

[0310] As another example, if the first common information field includes the first information, it can be implicitly recognized that this is an information request from APs corresponding to the same AP MLD, and therefore the first and second information may not be included in the first link information field.

[0311] The response frame may include a second presence bitmap subfield and a second common information field. The second presence bitmap subfield may include the second information indicating the presence of the first information. Whether the first information is included in the second common information field may be determined based on the value of the second information.

[0312] The above response frame may further include a second link information field.

[0313] For example, the first information may be included in the STA control field of the second link information field.

[0314] As another example, the second link information field may include a STA control field and a STA information field. The STA control field may include the second information. Whether the first information is included in the STA information field may be determined based on the value of the second information.

[0315] When roaming is determined from the first AP to the second AP, the first AP may receive an MLD roaming request frame from the first non-AP STA. The first AP may transmit an MLD roaming response frame to the first non-AP STA. The first non-AP STA may perform roaming from the first AP to the second AP based on the MLD roaming request frame and the MLD roaming response frame. (Alternatively, the first non-AP STA may transmit an MLD roaming request frame to the first AP. The first non-AP STA may receive an MLD roaming response frame from the first AP. The first AP may perform roaming from the first AP to the second AP based on the MLD roaming request frame and the MLD roaming response frame.)

[0316] The above MLD roaming request frame may be defined based on a Reconfiguration Multi-link Information Element (IE). The common information field of the MLD roaming request frame may include an identifier of the second AP MLD and an identifier of the group in which roaming is possible. The link information field of the MLD roaming request frame may include link identifiers of the first and second APs, an identifier of the second AP MLD, and an identifier of the group in which roaming is possible.

[0317] The above MLD roaming response frame may be defined based on the Basic Multi-link IE. The common information field of the MLD roaming response frame may include the identifier of the second AP MLD and the identifier of the group in which roaming is possible. The link information field of the MLD roaming response frame may include the link identifier of the second AP, the identifier of the second AP MLD, and the identifier of the group in which roaming is possible.

[0318] After roaming from the first AP to the second AP is completed, the first non-AP STA can receive the DL (downlink) data from the second AP.

[0319] <Device Configuration>

[0320] The technical features of the present specification described above can be applied to various devices and methods. For example, the technical features of the present specification described above can be performed / supported by the devices of FIG. 1 and / or FIG. 14. For example, the technical features of the present specification described above can be applied only to a part of FIG. 1 and / or FIG. 14. For example, the technical features of the present specification described above can be implemented based on the processing chip (114, 124) of FIG. 1, or based on the processor (111, 121) and memory (112, 122) of FIG. 1, or based on the processor (610) and memory (620) of FIG. 14. For example, the device of the present specification receives a management frame from a first access point (AP); and determines roaming from the first AP to a second AP based on the management frame.

[0321] The technical features of this specification can be implemented based on a computer-readable medium (CRM). For example, the CRM proposed by this specification is at least one computer-readable recording medium containing instructions that are executed by at least one processor.

[0322] The CRM may store instructions for performing operations including: receiving a management frame from a first AP (access point); and determining roaming from the first AP to a second AP based on the management frame. The instructions stored in the CRM of the present specification may be executed by at least one processor. At least one processor related to the CRM of the present specification may be the processor (111, 121) or processing chip (114, 124) of FIG. 1, or the processor (610) of FIG. 14. Meanwhile, the CRM of the present specification may be the memory (112, 122) of FIG. 1, the memory (620) of FIG. 14, or a separate external memory / storage medium / disk, etc.

[0323] The technical features of this specification described above are applicable to various applications and business models. For example, the technical features described above can be applied to wireless communication in devices that support artificial intelligence (AI).

[0324] Artificial intelligence (AI) is the study of artificial intelligence or the methodologies for creating it, while machine learning (ML) defines various problems in the field of AI and studies the methodologies for solving them. Machine learning is also defined as an algorithm that improves performance on a task through consistent experience.

[0325] An artificial neural network (ANN) is a model used in machine learning. It can refer to a model with problem-solving capabilities, consisting of artificial neurons (nodes) formed by the connection of synapses to form a network. An ANN can be defined by the connection patterns between neurons in different layers, the learning process that updates model parameters, and the activation function that generates output values.

[0326] An artificial neural network may include an input layer, an output layer, and optionally one or more hidden layers. Each layer contains one or more neurons, and the artificial neural network may include synapses connecting neurons. In an artificial neural network, each neuron can output a function value of an activation function based on input signals, weights, and biases received through the synapses.

[0327] Model parameters are parameters determined through learning, including synaptic connection weights and neuron biases. Hyperparameters are parameters that must be set before learning in machine learning algorithms, including the learning rate, number of iterations, mini-batch size, and initialization function.

[0328] The goal of artificial neural network training can be seen as determining model parameters that minimize a loss function. The loss function can be used as an indicator for determining optimal model parameters during the artificial neural network training process.

[0329] Machine learning can be classified into supervised learning, unsupervised learning, and reinforcement learning depending on the learning method.

[0330] Supervised learning refers to a method for training an artificial neural network when given labels for the training data. The labels can refer to the correct answer (or output value) that the artificial neural network must infer when the training data is input to the artificial neural network. Unsupervised learning can refer to a method for training an artificial neural network when the training data is not given labels. Reinforcement learning can refer to a learning method in which an agent defined within a given environment is trained to select actions or action sequences that maximize the cumulative reward in each state.

[0331] Machine learning implemented with a deep neural network (DNN) containing multiple hidden layers among artificial neural networks is also called deep learning, and deep learning is a subset of machine learning. Hereinafter, the term "machine learning" is used to encompass deep learning.

[0332] Additionally, the above-described technical features can be applied to wireless communication of robots.

[0333] A robot can be defined as a machine that automatically performs or operates a given task based on its own capabilities. Specifically, a robot capable of perceiving its environment, making independent judgments, and performing actions can be called an intelligent robot.

[0334] Robots can be categorized into industrial, medical, household, and military applications based on their intended use or field. Robots are equipped with actuators or motors, enabling them to perform various physical actions, such as moving robot joints. Furthermore, mobile robots incorporate wheels, brakes, and propellers into their actuators, enabling them to move on the ground or fly in the air.

[0335] Additionally, the above-described technical features can be applied to devices that support extended reality.

[0336] Extended reality is a general term for virtual reality (VR), augmented reality (AR), and mixed reality (MR). VR technology presents real-world objects and backgrounds as CG images only, AR technology presents virtual CG images over images of real objects, and MR technology is a computer graphics technology that blends and combines virtual objects with the real world.

[0337] MR technology is similar to AR in that it presents both real and virtual objects simultaneously. However, while AR uses virtual objects to complement real objects, MR uses virtual and real objects on an equal footing.

[0338] XR technology can be applied to HMD (Head-Mount Display), HUD (Head-Up Display), mobile phones, tablet PCs, laptops, desktops, TVs, digital signage, etc., and devices to which XR technology is applied can be called XR devices.

[0339] The claims set forth in this specification may be combined in various ways. For example, the technical features of the method claims of this specification may be combined and implemented as a device, and the technical features of the device claims of this specification may be combined and implemented as a method. Furthermore, the technical features of the method claims and the technical features of the device claims of this specification may be combined and implemented as a device, and the technical features of the method claims and the technical features of the device claims of this specification may be combined and implemented as a method.

Claims

1. In a wireless LAN system, A step in which a first non-AP STA (non-access point station) receives a management frame from a first AP; and The step of the first non-AP STA determining roaming from the first AP to the second AP based on the management frame includes: The above first AP belongs to the first AP MLD (multi-link device), and the above second AP belongs to the second AP MLD. The above management frame includes first information about whether the second AP is included in the same roaming-enabled group as the first AP, Based on the first information being set to 1, the second AP is included in the same roaming-enabled group as the first AP, and Based on the above first information being set to 0, the second AP is not included in the same roaming-enabled group as the first AP. method.

2. In paragraph 1, The above management frame is a beacon or probe response frame, The above first information is included in the TBTT (Target Beacon Transmission Time) information field of the RNR (Reduced Neighbor Report) IE (Information Element) of the beacon or probe response frame. method.

3. In paragraph 1, The step of the first non-AP STA transmitting a request frame to the first AP; and The first non-AP STA further comprises a step of receiving a response frame from the first AP, The above request frame includes a first presence bitmap subfield and a first common information field, The first existence bitmap subfield includes second information indicating the existence of the first information, It is determined whether the above first information is included in the above first common information field based on the value of the above second information. method.

4. In paragraph 3, The above request frame further includes a first link information field, The above first information is included in the STA control field of the first link information field. method.

5. In paragraph 3, The above request frame further includes a first link information field, The above first link information field includes a STA control field and a STA information field, The above STA control field includes the second information, It is determined whether the above first information is included in the STA information field based on the value of the above second information. method.

6. In paragraph 3, The above response frame includes a second presence bitmap subfield and a second common information field, The second existence bitmap subfield includes the second information indicating the existence of the first information, It is determined whether the above first information is included in the second common information field based on the value of the above second information. method.

7. In paragraph 6, The above response frame further includes a second link information field, The above first information is included in the STA control field of the above second link information field. method.

8. In paragraph 6, The above response frame further includes a second link information field, The second link information field includes a STA control field and a STA information field, The above STA control field includes the second information, It is determined whether the above first information is included in the STA information field based on the value of the above second information. method.

9. In paragraph 6, If roaming is decided from the above 1st AP to the 2nd AP, A step in which the first non-AP STA transmits an MLD roaming request frame to the first AP; The step of the first non-AP STA receiving an MLD roaming response frame from the first AP; and The first non-AP STA further includes a step of performing roaming from the first AP to the second AP based on the MLD roaming request frame and the MLD roaming response frame. method.

10. In paragraph 9, The above MLD roaming request frame is defined based on the Reconfiguration Multi-link IE (Information Element). The above MLD roaming response frame is defined based on the Basic Multi-link IE. method.

11. In a wireless LAN system, the first non-AP STA (non-access point station) memory; transceiver; and A processor operatively coupled with the memory and the transceiver, the processor comprising: Receive a management frame from the first AP; and Based on the above management frame, roaming is decided from the first AP to the second AP, The above first AP belongs to the first AP MLD (multi-link device), and the above second AP belongs to the second AP MLD. The above management frame includes first information about whether the second AP is included in the same roaming-enabled group as the first AP, Based on the first information being set to 1, the second AP is included in the same roaming-enabled group as the first AP, and Based on the above first information being set to 0, the second AP is not included in the same roaming-enabled group as the first AP. 1st non-AP STA.

12. In a wireless LAN system, A step in which the first AP (access point) transmits a management frame to the first non-AP STA (station); and The first AP comprises a step of determining roaming from the first AP to the second AP based on the management frame, The above first AP belongs to the first AP MLD (multi-link device), and the above second AP belongs to the second AP MLD. The above management frame includes first information about whether the second AP is included in the same roaming-enabled group as the first AP, Based on the first information being set to 1, the second AP is included in the same roaming-enabled group as the first AP, and Based on the above first information being set to 0, the second AP is not included in the same roaming-enabled group as the first AP. method.

13. In paragraph 12, The above management frame is a beacon or probe response frame, The above first information is included in the TBTT (Target Beacon Transmission Time) information field of the RNR (Reduced Neighbor Report) IE (Information Element) of the beacon or probe response frame. method.

14. In paragraph 12, The step of the AP receiving a request frame from the first non-AP STA; and The above AP further comprises a step of transmitting a response frame to the first non-AP STA, The above request frame includes a first presence bitmap subfield and a first common information field, The first existence bitmap subfield includes second information indicating the existence of the first information, It is determined whether the above first information is included in the above first common information field based on the value of the above second information. method.

15. In paragraph 14, The above request frame further includes a first link information field, The above first information is included in the STA control field of the first link information field. method.

16. In paragraph 14, The above request frame further includes a first link information field, The above first link information field includes a STA control field and a STA information field, The above STA control field includes the second information, It is determined whether the above first information is included in the STA information field based on the value of the above second information. method.

17. In paragraph 14, The above response frame includes a second presence bitmap subfield and a second common information field, The second existence bitmap subfield includes the second information indicating the existence of the first information, It is determined whether the above first information is included in the second common information field based on the value of the above second information. method.

18. In a wireless LAN system, the first AP (access point) is memory; transceiver; and A processor operatively coupled with the memory and the transceiver, the processor comprising: Transmitting a management frame to the first non-AP STA (station); and The above first AP determines roaming from the first AP to the second AP based on the management frame, The above first AP belongs to the first AP MLD (multi-link device), and the above second AP belongs to the second AP MLD. The above management frame includes first information about whether the second AP is included in the same roaming-enabled group as the first AP, Based on the first information being set to 1, the second AP is included in the same roaming-enabled group as the first AP, and Based on the above first information being set to 0, the second AP is not included in the same roaming-enabled group as the first AP. 1st AP.

19. At least one computer readable medium containing instructions based on being executed by at least one processor, A step of receiving a management frame from a first AP (access point); and Including a step of determining roaming from the first AP to the second AP based on the above management frame, The above first AP belongs to the first AP MLD (multi-link device), and the above second AP belongs to the second AP MLD. The above management frame includes first information about whether the second AP is included in the same roaming-enabled group as the first AP, Based on the first information being set to 1, the second AP is included in the same roaming-enabled group as the first AP, and Based on the above first information being set to 0, the second AP is not included in the same roaming-enabled group as the first AP. Recording medium.

20. In a wireless LAN system, for a device, memory; and A processor operatively coupled with said memory, said processor comprising: Receive a management frame from the first AP (access point); and Based on the above management frame, roaming is decided from the first AP to the second AP, The above first AP belongs to the first AP MLD (multi-link device), and the above second AP belongs to the second AP MLD. The above management frame includes first information about whether the second AP is included in the same roaming-enabled group as the first AP, Based on the first information being set to 1, the second AP is included in the same roaming-enabled group as the first AP, and Based on the above first information being set to 0, the second AP is not included in the same roaming-enabled group as the first AP. device.

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