Non-access point multi-link device and access point multi-

Abstract

The invention relates to a non-access point multi-link device and an access point multi-link device and a method of operating the same. According to various embodiments, a multilink device (MLD) operating in a plurality of links including a first link may transmit, by a first station (STA), a request frame including an information field for requesting at least one element related to a second link to a first AP of an AP multilink device. The multi-link device may receive at least one element related to the second link based on the request frame.

Description

[0001] This application is a divisional application of the invention patent application with the original application number 202180033223.6 (International Application No.: PCT / KR2021 / 002737, filing date: March 5, 2021, invention title: Method for performing multi-link communication in a wireless communication system). Technical Field

[0002] This specification relates to a method for performing multi-link communication in a wireless local area network (WLAN) system, and more particularly, to a method for transmitting information about a link in multi-link communication and an apparatus supporting the method. Background Art

[0003] Wireless local area network (WLAN) has been enhanced in various ways. For example, the IEEE 802.11ax standard has proposed an enhanced communication environment using orthogonal frequency division multiple access (OFDMA) and downlink multi-user multiple input multiple output (DL MU MIMO) schemes.

[0004] This specification presents technical features that can be used in new communication standards. For example, the new communication standard may be the extremely high throughput (EHT) standard currently under discussion. The EHT standard may use newly proposed increased bandwidth, enhanced physical layer protocol data unit (PPDU) structure, enhanced sequences, hybrid automatic repeat request (HARQ) schemes, etc. The EHT standard may be referred to as the IEEE 802.11be standard. Summary of the Invention

[0005] Technical Objectives

[0006] In the EHT specification, to support high throughput and high data rate, operations such as wide bandwidth (e.g., 160 / 320 MHz), 16 streams, and / or multi-link (or multi-band) may be used.

[0007] In the EHT specification, a device supporting multi-link (i.e., a multi-link device) may operate in multiple links. To switch the connected link, the multi-link device may need to receive information about another link that is not included in the multiple links. In addition, while performing communication through a first link, the multi-link device needs to receive information about at least one of the multiple links.

[0008] Therefore, the multi-link device may need technical features that enable the multi-link device to receive information about another link.

[0009] Technical Solutions

[0010] According to various embodiments, a multi-link device (MLD) connected to a plurality of links including a first link may perform the following steps: sending, via a first station (STA) included in the multi-link device, a request frame including an information field for requesting at least one element related to a second link to a first access point (AP) of the AP multi-link device, wherein the first STA operates in the first link, and wherein the information field includes information for identifying the at least one element; and receiving, via the first STA based on the request frame, a response frame from the first AP, wherein the response frame includes the at least one element.

[0011] Effects of the present disclosure

[0012] The STAs included in the multi-link device may transmit information related to other STAs within the multi-link device together via one link. Accordingly, frame exchange overhead may be reduced. Additionally, the link usage efficiency of the STAs may be increased, and power consumption may be reduced.

[0013] Additionally, a first STA included in the multi-link device may request per-link partial information. For example, a first STA of the multi-link device may request partial information related to a second link, and then, the first STA may receive the requested information. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 An example of a transmitting device and / or a receiving device of the present specification is shown.

[0015] Figure 2 It is a conceptual view showing the structure of a wireless local area network (WLAN).

[0016] Figure 3 A general link establishment process is shown.

[0017] Figure 4 An example of a PPDU used in the IEEE standard is shown.

[0018] Figure 5 The layout of resource units (RUs) used in a 20 MHz band is shown.

[0019] Figure 6 The layout of RUs used in a 40 MHz band is shown.

[0020] Figure 7 The layout of RUs used in an 80 MHz band is shown.

[0021] Figure 8 The structure of the HE-SIG-B field is shown.

[0022] Fig. 9Shows an example of allocating multiple user STAs to the same RU through the MU-MIMO scheme.

[0023] Fig.10 Shows operations based on UL-MU.

[0024] Fig.11 Shows an example of a trigger frame.

[0025] Fig.12 Shows an example of the common information field of a trigger frame.

[0026] Fig.13 Shows an example of the subfields included in the per-user information field.

[0027] Fig.14 Describes the technical features of the UORA scheme.

[0028] Fig.15 Shows an example of a channel used / supported / defined within the 2.4 GHz band.

[0029] Fig.16 Shows an example of a channel used / supported / defined within the 5 GHz band.

[0030] Fig.17 Shows an example of a channel used / supported / defined within the 6 GHz band.

[0031] Fig.18 Shows an example of a PPDU used in this specification.

[0032] Fig.19 Shows an example of a modified transmitting device and / or receiving device of this specification.

[0033] Fig. 20 Shows an example of a HE-PPDU.

[0034] Fig.21 Shows an example of channel bonding.

[0035] Fig. 22 Shows an exemplary structure of a non-AP MLD.

[0036] Fig.23 Shows an exemplary connection between an AP MLD and a non-AP MLD through a link establishment process.

[0037] Fig.24 Shows an example of a switched or reconnected link.

[0038] Fig.25 Shows a detailed example of a switched or reconnected link.

[0039] Fig.26Shows the operations of AP MLD and non-AP MLD for link switching or reconnection.

[0040] Fig. 27 Shows the operations of AP MLD and non-AP MLD for link switching or reconnection.

[0041] Fig.28 Shows the operations of AP MLD and non-AP MLD for link switching or reconnection.

[0042] Fig.29 Shows the operations of AP MLD and non-AP MLD for link switching or reconnection.

[0043] Fig.30 Shows the operations on non-AP MLD for requesting information about other APs.

[0044] Fig.31 Shows a detailed example of the per-link STA ratio.

[0045] Fig.32 Shows the operations of AP MLD and non-AP MLD for link switching or reconnection.

[0046] Fig.33 Shows the operations of AP MLD and non-AP MLD for link switching or reconnection.

[0047] Fig.34 Shows the operations of AP MLD and non-AP MLD for link switching or reconnection.

[0048] Fig.35 Shows an example of the MLD structure supporting an anchored link.

[0049] Fig.36 Shows an example of a situation requiring an anchored link switch or reconnection.

[0050] Fig.37 Shows the operations of AP MLD and non-AP MLD for anchored link switching or reconnection.

[0051] Fig.38 and Fig.39 respectively show detailed examples of the elements for anchored link reconnection.

[0052] Fig.40 Shows an example of a multi-link element.

[0053] Fig.41 Shows another example of a multi-link element.

[0054] Fig.42Shows an example of the field configuration proposed in this specification.

[0055] Fig.43 Shows a detailed example of the request element format.

[0056] Fig.44 Shows a detailed example of the extended request element format.

[0057] Fig.45 Shows a detailed example of the PV1 probe response option element format.

[0058] Fig.46 Shows an example of the MLD request element.

[0059] Fig.47 Shows another example of the MLD request element.

[0060] Fig.48 Shows another example of the MLD request element.

[0061] Fig.49 Shows another example of the MLD request element.

[0062] Fig.50 Shows another example of the MLD request element.

[0063] Fig.51 Shows another example of the MLD request element.

[0064] Fig.52 Shows another example of the MLD request element.

[0065] Fig.53 Shows an example of the element for requesting public information.

[0066] Fig.54 Shows an example of the multi-link element format.

[0067] Fig.55 Shows another example of the multi-link element format.

[0068] Fig.56 Shows an example of the multi-link control field format.

[0069] Fig.57 Shows an example of the multi-link control field format.

[0070] Fig.58 Shows another example of the multi-link element format.

[0071] Fig.59 Shows another example of the multi-link element format.

[0072] Fig.60 Shows an example of the multi-link element format and additional elements.

[0073] Fig.61 Shows another example of the multi-link element format and additional elements.

[0074] Fig.62 Shows an example of the multi-link control field format.

[0075] Fig.63 Shows another example of the multi-link element format.

[0076] Fig.64 Shows another example of the multi-link element format.

[0077] Fig.65 Shows another example of the multi-link element format.

[0078] Fig.66 and Fig.67 Shows an example of the MLD change sequence element format.

[0079] Fig.68 Shows another example of the multi-link element format.

[0080] Fig.69 Shows an example of the change sequence element format.

[0081] Fig.70 Shows another example of the multi-link element format.

[0082] Fig.71 Shows another example of the multi-link element format.

[0083] Fig.72 Shows another example of the multi-link element format.

[0084] Fig.73 Shows another example of the multi-link element format.

[0085] Fig.74 Shows another example of the multi-link element format.

[0086] Fig.75 Is a flowchart describing the operation of a multi-link device.

[0087] Fig.76 Is a flowchart describing the operation of an AP multi-link device. Detailed Description

[0088] In this specification, "A or B" may mean "only A", "only B", or "both A and B". In other words, in this specification, "A or B" can be interpreted as "A and / or B". For example, in this specification, "A, B, or C" may mean "only A", "only B", "only C", or "any combination of A, B, and C".

[0089] The slashes ( / ) or commas used in this specification may represent "and / or". For example, "A / B" may represent "A and / or B". Therefore, "A / B" may represent "only A", "only B", or "both A and B". For example, "A, B, C" may represent "A, B, or C".

[0090] In this specification, "at least one of A and B" may represent "only A", "only B", or "both A and B". Additionally, in this specification, the expression "at least one of A or B" or "at least one of A and / or B" may be interpreted as "at least one of A and B".

[0091] Furthermore, in this specification, "at least one of A, B, and C" may represent "only A", "only B", "only C", or "any combination of A, B, and C". Additionally, "at least one of A, B, or C" or "at least one of A, B, and / or C" may represent "at least one of A, B, and C".

[0092] Moreover, the parentheses used in this specification may represent "for example". Specifically, when indicated as "control information (EHT - signal)", it may mean that "EHT - signal" is proposed as an example of "control information". In other words, the "control information" in this specification is not limited to "EHT - signal", and "EHT - signal" can be presented as an example of "control information". Additionally, when indicated as "control information (i.e., EHT signal)", it may also mean that "EHT signal" is proposed as an example of "control information".

[0093] The technical features separately described in one drawing of this specification can be implemented separately or simultaneously.

[0094] 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 a wireless local area network (WLAN) system. For example, this specification can be applied to the IEEE 802.11a / g / n / ac standard or the IEEE802.11ax standard. Additionally, this specification can also be applied to the newly proposed EHT standard or the IEEE 802.11be standard. Furthermore, the examples of this specification can also be applied to the new WLAN standards enhanced from the EHT standard or the IEEE 802.11be standard. Additionally, the examples of this specification can be applied to a mobile communication system. For example, it can be applied to the long - term evolution (LTE) based on the 3rd Generation Partnership Project (3GPP) standard and the mobile communication systems evolved from LTE. Additionally, the examples of this specification can be applied to a communication system based on the 5G NR standard of the 3GPP standard.

[0095] In the following, in order to describe the technical features of this specification, the technical features applicable to this specification will be described.

[0096] Figure 1 Examples of the transmitting device and / or receiving device of this specification are shown.

[0097] In Figure 1 the example of, various technical features described below can be executed. Figure 1 It relates to at least one station (STA). For example, STA 110 and 120 of this specification can also be referred to by various terms such as mobile terminal, wireless device, wireless transmit / receive unit (WTRU), user equipment (UE), mobile station (MS), mobile subscriber unit or simply referred to as user. STA 110 and 120 of this specification can also be referred to by various terms such as network, base station, Node B, access point (AP), repeater, router, repeater, etc. STA 110 and 120 of this specification can also be referred to by various names such as receiving device, transmitting device, receiving STA, transmitting STA, receiving equipment, transmitting equipment, etc.

[0098] For example, STA 110 and 120 can be used as an AP or a non-AP. That is, STA 110 and 120 of this specification can be used as an AP and / or a non-AP.

[0099] In addition to the IEEE 802.11 standard, STA 110 and 120 of this specification can together support various communication standards. For example, communication standards based on 3GPP standards (e.g., LTE, LTE-A, 5G NR standards), etc. can be supported. In addition, the STA of this specification can be implemented as various devices such as mobile phones, vehicles, personal computers, etc. In addition, the STA of this specification can support communication for various communication services such as voice calls, video calls, data communication, and self-driving (autonomous driving).

[0100] STA 110 and 120 of this specification can include a media access control (MAC) conforming to the IEEE 802.11 standard and a physical layer interface for the radio medium.

[0101] Below, reference will be made to Figure 1 subfigure (a) of to describe STA 110 and 120.

[0102] The first STA 110 can include a processor 111, a memory 112, and a transceiver 113. The shown processing, memory, and transceiver can be implemented separately as separate chips, or at least two blocks / functions can be implemented by a single chip.

[0103] The transceiver 113 of the first STA performs signal transmission / reception operations. Specifically, IEEE 802.11 packets (e.g., IEEE 802.11a / b / g / n / ac / ax / be, etc.) can be transmitted / received.

[0104] For example, the first STA 110 can perform operations expected by an AP. For example, the processor 111 of the AP can receive signals through the transceiver 113, process the received (RX) signals, generate transmission (TX) signals, and provide control for signal transmission. The memory 112 of the AP can store the signals received through the transceiver 113 (e.g., RX signals), and can store the signals to be transmitted through the transceiver (e.g., TX signals).

[0105] For example, the second STA 120 can perform operations expected by a non-AP STA. For example, the transceiver 123 of the non-AP performs signal transmission / reception operations. Specifically, IEEE 802.11 packets (e.g., IEEE 802.11a / b / g / n / ac / ax / be packets, etc.) can be transmitted / received.

[0106] For example, the processor 121 of the non-AP STA can receive signals through the transceiver 123, process the RX signals, generate TX signals, and provide control for signal transmission. The memory 122 of the non-AP STA can store the signals received through the transceiver 123 (e.g., RX signals), and can store the signals to be transmitted through the transceiver (e.g., TX signals).

[0107] For example, the operations of the device indicated as an AP in the following described specification can be performed in the first STA 110 or the second STA 120. For example, if the first STA 110 is an AP, the operations of the device indicated as an AP can be controlled by the processor 111 of the first STA 110, and the relevant signals can be transmitted or received through the transceiver 113 controlled by the processor 111 of the first STA 110. Additionally, the control information related to the operations of the AP or the TX / RX signals of the AP can be stored in the memory 112 of the first STA 110. Additionally, if the second STA 120 is an AP, the operations of the device indicated as an AP can be controlled by the processor 121 of the second STA 120, and the relevant signals can be transmitted or received through the transceiver 123 controlled by the processor 121 of the second STA 120. Additionally, the control information related to the operations of the AP or the TX / RX signals of the AP can be stored in the memory 122 of the second STA 120.

[0108] For example, in the specification described below, the operations of a device indicated as a non-AP (or user STA) can be executed in the first STA 110 or the second STA 120. For example, if the second STA 120 is a non-AP, the operations of the device indicated as a non-AP can be controlled by the processor 121 of the second STA 120, and the relevant signals can be transmitted or received through the transceiver 123 controlled by the processor 121 of the second STA 120. Additionally, the control information related to the operations of the non-AP or the TX / RX signals of the non-AP can be stored in the memory 122 of the second STA 120. For example, if the first STA 110 is a non-AP, the operations of the device indicated as a non-AP can be controlled by the processor 111 of the first STA 110, and the relevant signals can be transmitted or received through the transceiver 113 controlled by the processor 111 of the first STA 110. Additionally, the control information related to the operations of the non-AP or the TX / RX signals of the non-AP can be stored in the memory 112 of the first STA 110.

[0109] In the specification described below, devices such as (transmit / receive) STA, first STA, second STA, STA1, STA2, AP, first AP, second AP, AP1, AP2, (transmit / receive) terminal, (transmit / receive) device, (transmit / receive) apparatus, network, etc. may mean Figure 1 the STAs 110 and 120. For example, a device indicated as (but without specific labeling) (transmit / receive) STA, first STA, second STA, STA1, STA2, AP, first AP, second AP, AP1, AP2, (transmit / receive) terminal, (transmit / receive) device, (transmit / receive) apparatus, network, etc. may mean Figure 1 the STAs 110 and 120. For example, in the following examples, the operations of various STAs for transmitting / receiving signals (e.g., PPDU) can be executed in Figure 1 the transceivers 113 and 123. Additionally, in the following examples, the operations of various STAs for generating TX / RX signals or pre-executing data processing and calculations for TX / RX signals can be executed in Figure 1Execute in processors 111 and 121. For example, examples of operations for generating TX / RX signals or pre-executing data processing and calculations may include: 1) operations for determining / acquiring / configuring / calculating / decoding / encoding bit information of sub-fields (SIG, STF, LTF, data) included in a PPDU; 2) operations for determining / configuring / acquiring time resources or frequency resources (e.g., sub-carrier resources) for sub-fields (SIG, STF, LTF, data) included in a PPDU; 3) operations for determining / configuring / acquiring specific sequences (e.g., pilot sequences, STF / LTF sequences, additional sequences applied to SIG) for sub-fields (SIG, STF, LTF, data) fields included in a PPDU; 4) power control operations and / or power-saving operations applied to a STA; and 5) operations related to the determination / acquisition / configuring / decoding / encoding of ACK signals. Additionally, in the following examples, various information (e.g., information related to fields / sub-fields / control fields / parameters / power, etc.) used by various STAs to determine / acquire / configure / calculate / decode / encode TX / RX signals may be stored in Figure 1 memories 112 and 122.

[0110] Figure 1 The aforementioned device / STA in sub-graph (a) of Figure 1 may be modified as shown in sub-graph (b) of Figure 1 STA 110 and STA 120 of this specification will be described based on sub-graph (b) of

[0111] For example, Figure 1 Transceivers 113 and 123 shown in sub-graph (b) of Figure 1 may perform the same functions as the aforementioned transceivers shown in sub-graph (a) of Figure 1 Processing chips 114 and 124 shown in sub-graph (b) of Figure 1 may include processors 111 and 121 and memories 112 and 122. Figure 1 Processors 111 and 121 and memories 112 and 122 shown in sub-graph (b) of

[0112] The mobile terminals, wireless devices, wireless transmit / receive units (WTRUs), user equipments (UEs), mobile stations (MSs), mobile subscriber units, users, user STAs, networks, base stations, Node Bs, access points (APs), repeaters, routers, relays, receiving units, transmitting units, receiving STAs, transmitting STAs, receiving devices, transmitting devices, receiving apparatuses, and / or transmitting apparatuses described below may mean Figure 1 the STAs 110 and 120 shown in sub - figure (a) / (b) of, or may mean Figure 1 the processing chips 114 and 124 shown in sub - figure (b) of. That is, the technical features of this specification can be executed in Figure 1 the STAs 110 and 120 shown in sub - figure (a) / (b) of, or can be executed only in Figure 1 the processing chips 114 and 124 shown in sub - figure (b) of Figure 1 the transceivers 113 and 123 shown in sub - figure (a) / (b) of. For example, the technical feature that the transmitting STA transmits a control signal can be understood as transmitting, through Figure 1 the transceivers 113 shown in sub - figure (a) / (b) of, the control signal generated in Figure 1 the processors 111 and 121 shown in sub - figure (a) / (b) of. Alternatively, the technical feature that the transmitting STA transmits a control signal can be understood as a technical feature of generating, in Figure 1 the processing chips 114 and 124 shown in sub - figure (b) of, the control signal to be transmitted to the transceivers 113 and 123.

[0113] For example, the technical feature that the receiving STA receives a control signal can be understood as a technical feature of receiving a control signal through Figure 1 the transceivers 113 and 123 shown in sub - figure (a) of. Alternatively, the technical feature that the receiving STA receives a control signal can be understood as obtaining, through Figure 1 the processors 111 and 121 shown in sub - figure (a) of, the control signal received in Figure 1 the transceivers 113 and 123 shown in sub - figure (a) of. Alternatively, the technical feature that the receiving STA receives a control signal can be understood as obtaining, through Figure 1 the processing chips 114 and 124 shown in sub - figure (b) of, the control signal received in Figure 1 the transceivers 113 and 123 shown in sub - figure (b) of.

[0114] Referring to Figure 1 sub - figure (b) of, the software codes 115 and 125 can be included in the memories 112 and 122. The software codes 115 and 126 can include instructions for controlling the operations of the processors 111 and 121. The software codes 115 and 125 can be included in various programming languages.

[0115] Figure 1 The processors 111 and 121 or the processing chips 114 and 124 of can include application - specific integrated circuits (ASICs), other chip sets, logic circuits, and / or data processing devices. The processor can be an application processor (AP). For example, Figure 1 The processors 111 and 121 or the processing chips 114 and 124 may include at least one of the following: a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), and a modulator and a demodulator (modem). For example, Figure 1 the processors 111 and 121 or the processing chips 114 and 124 may be the SNAPDRAGONTM processor series manufactured by the EXYNOSTM processor series manufactured by a processor series manufactured by the HELIOTM processor series manufactured by the ATOMTM processor series manufactured by or processors enhanced from these processors.

[0116] In this specification, the uplink may mean a link for communication from a non-AP STA to an SP STA, and an uplink PPDU / packet / signal, etc. may be transmitted through the uplink. Additionally, in this specification, the downlink may mean a link for communication from an AP STA to a non-AP STA, and a downlink PPDU / packet / signal, etc. may be transmitted through the downlink.

[0117] Figure 2 is a conceptual diagram showing the structure of a wireless local area network (WLAN).

[0118] Figure 2 The upper part of

[0119] shows the structure of an infrastructure basic service set (BSS) of the Institute of Electrical and Electronics Engineers (IEEE) 802.11. Figure 2 Referring to Figure 2 the upper part of, a wireless LAN system may include one or more infrastructure BSSs 200 and 205 (hereinafter referred to as BSSs). The BSSs 200 and 205, as a set of an AP and STAs (e.g., access point (AP) 225 and station (STA1) 200-1) that have successfully synchronized to communicate with each other, are not a concept indicating a specific area. The BSS 205 may include one or more STAs 205-1 and 205-2 that can join one AP 230.

[0120] A BSS may include at least one STA, an AP providing distributed services, and a distributed system (DS) 210 connecting multiple APs.

[0121] The distributed system 210 can implement an Extended Service Set (ESS) 240 that is extended by connecting multiple BSSs 200 and 205. The ESS 240 can be used as a term indicating a network configured by connecting one or more APs 225 or 230 via the distributed system 210. The APs included in one ESS 240 can have the same Service Set Identifier (SSID).

[0122] The portal 220 can be used as a bridge to connect a wireless LAN network (IEEE 802.11) and another network (e.g., 802.X).

[0123] In Figure 2 In the BSS shown in the upper part of, a network between APs 225 and 230 and a network between APs 225 and 230 and STAs 200-1, 205-1, and 205-2 can be implemented. However, a network is configured between STAs to perform communication even in the absence of APs 225 and 230. A network that performs communication by configuring a network between STAs even in the absence of APs 225 and 230 is defined as an ad-hoc network or an Independent Basic Service Set (IBSS).

[0124] Figure 2 The lower part of shows a conceptual diagram showing an IBSS.

[0125] Referring to Figure 2 the lower part of, the IBSS is a BSS that operates in ad-hoc mode. Since the IBSS does not include an access point (AP), there is no centralized management entity that performs management functions at the center. That is, in the IBSS, STAs 250-1, 250-2, 250-3, 255-4, and 255-5 are managed in a distributed manner. In the IBSS, all STAs 250-1, 250-2, 250-3, 255-4, and 255-5 can be composed of mobile STAs, and access to the DS is not allowed to form a self-contained network.

[0126] Figure 3 Describe the general link establishment process.

[0127] In S310, the STA can perform a network discovery operation. The network discovery operation can include a scanning operation of the STA. That is, in order to access the network, the STA needs to discover the participating network. The STA needs to identify a compatible network before joining the wireless network, and the process of identifying the networks existing in a specific area is called scanning. The scanning methods include active scanning and passive scanning.

[0128] Figure 3The description includes network discovery operations involving active scanning processing. In active scanning, the STA performing the scan sends a probe request frame and waits for a response to the probe request frame to identify which APs are present in the vicinity while moving to channels. The responder sends a probe response frame to the STA that has sent the probe request frame as a response to the probe request frame. Here, the responder can be the STA that sent the last beacon frame in the BSS of the channel being scanned. In a BSS, since the AP sends beacon frames, the AP is the responder. In an IBSS, since the STAs in the IBSS take turns sending beacon frames, the responder is not fixed. For example, when the STA sends a probe request frame via channel 1 and receives a probe response frame via channel 1, the STA can store the BSS-related information included in the received probe response frame, move to the next channel (e.g., channel 2), and perform scanning by the same method (e.g., send a probe request and receive a probe response via channel 2).

[0129] Although Figure 3 not shown in the figure, scanning can be performed by a passive scanning method. In passive scanning, the STA performing the scan can wait for beacon frames while moving to channels. A beacon frame is one of the management frames in IEEE 802.11 and is sent periodically to indicate the presence of a wireless network and enable the STA performing the scan to find and join the wireless network. In a BSS, the AP is used to send beacon frames periodically. In an IBSS, the STAs in the IBSS take turns sending beacon frames. When receiving a beacon frame, the STA performing the scan stores the information about the BSS included in the beacon frame and records the beacon frame information in each channel while moving to another channel. The STA that receives the beacon frame can store the BSS-related information included in the received beacon frame, move to the next channel, and perform scanning in the next channel by the same method.

[0130] After discovering the network, the STA can perform an authentication process in S320. This authentication process can be referred to as the first authentication process to clearly distinguish it from the security establishment operation in S340 subsequently. The authentication process in S320 can include the process of the STA sending an authentication request frame to the AP and the AP sending an authentication response frame to the STA as a response. The authentication frame for authentication request / response is a management frame.

[0131] The authentication frame can include information about the authentication algorithm number, authentication transaction sequence number, status code, challenge text, Robust Security Network (RSN), and finite cyclic group.

[0132] The STA can send an authentication request frame to the AP. The AP can determine whether to allow the authentication of the STA based on the information included in the received authentication request frame. The AP can provide the authentication processing result to the STA via the authentication response frame.

[0133] When the STA is successfully authenticated, the STA can perform an association process in S330. The association process includes the process of the STA sending an association request frame to the AP and the AP sending an association response frame to the STA as a response. For example, the association request frame may include information about various capabilities, a beacon listening interval, a service set identifier (SSID), supported rates, supported channels, an RSN, a mobility domain, supported operation classes, a traffic indication map (TIM) broadcast request, and an interworking service capability. For example, the association response frame may include information about various capabilities, a status code, an association ID (AID), supported rates, an enhanced distributed channel access (EDCA) parameter set, a received channel power indicator (RCPI), a received signal-to-noise ratio indicator (RSNI), a mobility domain, a timeout interval (association recovery time), an overlapping BSS scan parameter, a TIM broadcast response, and a QoS map.

[0134] In S340, the STA can perform a security establishment process. The security establishment process in S340 may include the process of establishing a private key through a four-way handshake (e.g., through an Extensible Authentication Protocol over LAN (EAPOL) frame).

[0135] Figure 4 Describe an example of a PPDU used in the IEEE standard.

[0136] As shown, various types of Physical Layer Protocol Data Units (PPDUs) are used in the IEEE a / g / n / ac standards. Specifically, the LTF and STF include training signals, the SIG-A and SIG-B include control information for the receiving STA, and the data field includes user data corresponding to the PSDU (MAC PDU / aggregated MAC PDU).

[0137] Figure 4 Also included is an example of a HE PPDU according to IEEE 802.11ax. According to Figure 4 the HE PPDU is an exemplary PPDU for multiple users. The HE-SIG-B may only be included in the PPDU for multiple users and may be omitted in the PPDU for a single user.

[0138] As Figure 4As shown, a HE-PPDU for multiple users (MUs) may include a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal (L-SIG), a high efficiency signal A (HE-SIG A), a high efficiency signal B (HE-SIG B), a high efficiency short training field (HE-STF), a high efficiency long training field (HE-LTF), a data field (alternatively, a MAC payload), and a packet extension (PE) field. Each field may be transmitted within the shown time period (i.e., 4 or 8 μs).

[0139] Below, the resource unit (RU) for a PPDU is described. An RU may include multiple subcarriers (or tones). An RU may be used to transmit signals to multiple STAs according to OFDMA. Additionally, an RU may also be defined to transmit signals to one STA. An RU may be used for STF, LTF, data fields, etc.

[0140] Figure 5 Illustrate the layout of the resource unit (RU) used in a 20 MHz frequency band.

[0141] As Figure 5 shown, resource units (RUs) corresponding to different numbers of tones (i.e., subcarriers) may be used to form some fields of a HE-PPDU. For example, resources may be allocated for HE-STF, HE-LTF, and data fields in the shown RUs.

[0142] As Figure 5 shown at the topmost part of, 26 units (i.e., units corresponding to 26 tones) may be set. Six tones may be used for the guard band in the leftmost frequency band of the 20 MHz frequency band, and five tones may be used for the guard band in the rightmost frequency band of the 20 MHz frequency band. Additionally, seven DC tones may be inserted in the center frequency band (i.e., the DC band), and 26 units corresponding to 13 tones on each side of the DC band may be set. 26 units, 52 units, and 106 units may be allocated to other frequency bands. Each unit may be allocated to a receiving STA (i.e., a user).

[0143] Figure 5 The layout of the RU in may be used not only for multiple users (MUs), but also for a single user (SU), in which case one 242-unit may be used and three DC tones may be inserted, as Figure 5 shown at the bottommost part of.

[0144] Although Figure 5RUs of various sizes are proposed, i.e., 26-RU, 52-RU, 106-RU, and 242-RU, but the RUs of a specific size can be extended or increased. Therefore, this embodiment is not limited to each RU of a specific size (i.e., the number of corresponding tones).

[0145] Figure 6 Describe the layout of the RUs used in the 40 MHz frequency band.

[0146] Similar to using RUs of various sizes Figure 5 , in Figure 6 's example, 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, etc. can be used. In addition, five DC tones can be inserted at the center frequency, 12 tones can be used for the guard band in the leftmost band of the 40 MHz frequency band, and 11 tones can be used for the guard band in the rightmost band of the 40 MHz frequency band.

[0147] As Figure 6 shown, when the layout of the RUs is used for a single user, 484-RU can be used. The specific number of RUs can be changed similar to Figure 5 .

[0148] Figure 7 Describe the layout of the RUs used in the 80 MHz frequency band.

[0149] Similar to using RUs of various sizes Figure 5 and Figure 6 , in Figure 7 's example, 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, 996-RU, etc. can be used. In addition, seven DC tones can be inserted at the center frequency, 12 tones can be used for the guard band in the leftmost band of the 80 MHz frequency band, and 11 tones can be used for the guard band in the rightmost band of the 80 MHz frequency band. Additionally, 26-RU corresponding to 13 tones on each side of the left and right of the DC band can be used.

[0150] As Figure 7 shown, when the layout of the RUs is used for a single user, 996-RU can be used, and in this case, five DC tones can be inserted.

[0151] The RU described in this specification can be used in both uplink (UL) communication and downlink (DL) communication. For example, when performing UL-MU communication requested by a trigger frame, the transmitting STA (e.g., AP) can allocate a first RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to a first STA through the trigger frame, and can allocate a second RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to a second STA. Thereafter, the first STA can send a first trigger-based PPDU based on the first RU, and the second STA can send a second trigger-based PPDU based on the second RU. The first / second trigger-based PPDUs are sent to the AP in the same (or overlapping) time period.

[0152] For example, when configuring a DL MU PPDU, the transmitting STA (e.g., AP) can allocate a first RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to a first STA, and can allocate a second RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to a second STA. That is, the transmitting STA (e.g., AP) can send the HE-STF, HE-LTF, and data fields for the first STA through the first RU in one MU PPDU, and can send the HE-STF, HE-LTF, and data fields for the second STA through the second RU.

[0153] Information related to the layout of the RU can be signaled through HE-SIG-B.

[0154] Figure 8 Describe the structure of the HE-SIG-B field.

[0155] As shown, the HE-SIG-B field 810 includes a common field 820 and a user-specific field 830. The common field 820 can include information that is commonly applied to all users (i.e., user STAs) receiving SIG-B. The user-specific field 830 can be referred to as a user-specific control field. When SIG-B is transmitted to multiple users, the user-specific field 830 can be applied only to any one of the multiple users.

[0156] As Figure 8 shown, the common field 820 and the user-specific field 830 can be encoded separately.

[0157] The common field 820 can include N*8-bit RU allocation information. For example, the RU allocation information can include information related to the position of the RU. For example, when using a 20MHz channel as Figure 5 shown, the RU allocation information can include information related to the specific frequency band where a specific RU (26-RU / 52-RU / 106-RU) is arranged.

[0158] An example of the case where the RU allocation information consists of 8 bits is as follows.

[0159] [Table 1]

[0160]

[0161] As Figure 5 shown in the example of, up to nine 26-RUs can be allocated to a 20 MHz channel. When the RU allocation information of the common field 820 is set to "00000000" as shown in Table 1, nine 26-RUs can be allocated to the corresponding channel (i.e., 20 MHz). Additionally, when the RU allocation information of the common field 820 is set to "00000001" as shown in Table 1, seven 26-RUs and one 52-RU are arranged in the corresponding channel. That is, in the Figure 5 example of, the 52-RU can be allocated to the rightmost side, and seven 26-RUs can be allocated to its left side.

[0162] The example of Table 1 only shows some RU positions where the RU allocation information can be displayed.

[0163] For example, the RU allocation information can include the example of Table 2 below.

[0164] [Table 2]

[0165]

[0166] "01000y2y1y0" relates to an example of allocating a 106-RU to the leftmost side of a 20 MHz channel and five 26-RUs to its right side. In this case, multiple STAs (e.g., user STAs) can be allocated to the 106-RU based on the MU-MIMO scheme. Specifically, up to 8 STAs (e.g., user STAs) can be allocated to the 106-RU, and the number of STAs (e.g., user STAs) allocated to the 106-RU is determined based on 3-bit information (y2y1y0). For example, when the 3-bit information (y2y1y0) is set to N, the number of STAs (e.g., user STAs) allocated to the 106-RU based on the MU-MIMO scheme can be N + 1.

[0167] Generally, multiple different STAs (e.g., user STAs) can be allocated to multiple RUs. However, multiple STAs (e.g., user STAs) can be allocated to one or more RUs having at least a specific size (e.g., 106 subcarriers) based on the MU-MIMO scheme.

[0168] As Figure 8As shown, the user-specific field 830 may include multiple user fields. As described above, the number of STAs (e.g., user STAs) assigned to a specific channel may be determined based on the RU allocation information in the common field 820. For example, when the RU allocation information in the common field 820 is "00000000", one user STA may be assigned to each of the nine 26-RUs (e.g., nine user STAs may be assignable). That is, up to 9 user STAs may be assigned to a specific channel through the OFDMA scheme. In other words, up to 9 user STAs may be assigned to a specific channel through the non-MU-MIMO scheme.

[0169] For example, when the RU allocation is set to "01000y2y1y0", multiple STAs may be assigned to the 106-RU arranged on the far left through the MU-MIMO scheme, and five user STAs may be assigned to the five 26-RUs arranged on its right through the non-MU MIMO scheme. This case is illustrated by Fig. 9 an example.

[0170] Fig. 9 An example of assigning multiple user STAs to the same RU through the MU-MIMO scheme is described.

[0171] For example, when the RU allocation is set to "01000010" as Fig. 9 shown, the 106-RU may be assigned to the far left of the specific channel, and five 26-RUs may be assigned to its right. Additionally, three user STAs may be assigned to the 106-RU through the MU-MIMO scheme. As a result, since eight user STAs are assigned, the user-specific field 830 of the HE-SIG-B may include eight user fields.

[0172] The eight user fields may be represented in the order as Fig. 9 shown. Additionally, as Figure 8 shown, two user fields may be implemented using one user block field.

[0173] Figure 8 and Fig. 9 shown, the user fields may be configured based on two formats. That is, the user fields related to the MU-MIMO scheme may be configured in the first format, and the user fields related to the non-MIMO scheme may be configured in the second format. Referring to Fig. 9 the example, user fields 1 to user fields 3 may be based on the first format, and user fields 4 to user fields 8 may be based on the second format. The first format or the second format may include bit information of the same length (e.g., 21 bits).

[0174] Each user field can have the same size (e.g., 21 bits). For example, the user field of the first format (the first MU-MIMO scheme) can be configured as follows.

[0175] For example, the first bit (i.e., B0 - B10) in the user field (i.e., 21 bits) can include the identification information of the user STA that is allocated the corresponding user field (e.g., STA-ID, partial AID, etc.). In addition, the second bit (i.e., B11 - B14) in the user field (i.e., 21 bits) can include information related to the spatial configuration. Specifically, examples of the second bit (i.e., B11 - B14) can be as shown in Table 3 and Table 4 below.

[0176] [Table 3]

[0177]

[0178] [Table 4]

[0179]

[0180] As shown in Table 3 and / or Table 4, the second bit (e.g., B11 - B14) can include information related to the number of spatial streams allocated to multiple user STAs based on the MU-MIMO scheme. For example, when three user STAs are allocated to 106-RU as shown in Fig. 9 , N_user is set to "3". Therefore, the values of N_STS[1], N_STS[2], and N_STS[3] can be determined as shown in Table 3. For example, when the value of the second bit (B11 - B14) is "0011", it can be set to N_STS[1]=4, N_STS[2]=1, N_STS[3]=1. That is, in the example of Fig. 9 , four spatial streams can be allocated to user field 1, one spatial stream can be allocated to user field 1, and one spatial stream can be allocated to user field 3.

[0181] As shown in the examples of Table 3 and / or Table 4, the information related to the number of spatial streams for the user STA (i.e., the second bit, B11 - B14) can consist of 4 bits. In addition, the information about the number of spatial streams for the user STA (i.e., the second bit, B11 - B14) can support up to eight spatial streams. In addition, the information about the number of spatial streams for the user STA (i.e., the second bit, B11 - B14) can support up to four spatial streams for one user STA.

[0182] In addition, the third bit (i.e., B15-18) in the user field (i.e., 21 bits) may include modulation and coding scheme (MCS) information. The MCS information may be applied to the data field in the PPDU including the corresponding SIG-B.

[0183] The MCS, MCS information, MCS index, MCS field, etc. used in this specification may be indicated by index values. For example, the MCS information may be indicated by index 0 to index 11. The MCS information may include information related to the constellation modulation type (e.g., BPSK, QPSK, 16-QAM, 64-QAM, 256-QAM, 1024-QAM, etc.) and information related to the coding rate (e.g., 1 / 2, 2 / 3, 3 / 4, 5 / 6e, etc.). Information related to the channel coding type (e.g., LCC or LDPC) may not be included in the MCS information.

[0184] In addition, the fourth bit (i.e., B19) in the user field (i.e., 21 bits) may be a reserved field.

[0185] In addition, the fifth bit (i.e., B20) in the user field (i.e., 21 bits) may include information related to the coding type (e.g., BCC or LDPC). That is, the fifth bit (i.e., B20) may include information related to the type of channel coding (e.g., BCC or LDPC) applied to the data field in the PPDU including the corresponding SIG-B.

[0186] The above example relates to the user field of the first format (the format of the MU-MIMO scheme). Examples of the user field of the second format (the format of the non-MU-MIMO scheme) are as follows.

[0187] The first bit (e.g., B0-B10) in the user field of the second format may include the identification information of the user STA. In addition, the second bit (e.g., B11-B13) in the user field of the second format may include information related to the number of spatial streams applied to the corresponding RU. In addition, the third bit (e.g., B14) in the user field of the second format may include information related to whether to apply the beamforming steering matrix. The fourth bit (e.g., B15-B18) in the user field of the second format may include modulation and coding scheme (MCS) information. In addition, the fifth bit (e.g., B19) in the user field of the second format may include information related to whether to apply dual carrier modulation (DCM). In addition, the sixth bit (i.e., B20) in the user field of the second format may include information related to the coding type (e.g., BCC or LDPC).

[0188] Fig.10Shows UL-MU-based operations. As shown, the transmitting STA (e.g., AP) can perform channel access through contention (e.g., backoff operations) and can send a trigger frame 1030. That is, the transmitting STA can send a PPDU including the trigger frame 1030. Upon receiving a PPDU including a trigger frame, a trigger-based (TB) PPDU is sent after a delay corresponding to the SIFS.

[0189] TB PPDUs 1041 and 1042 can be sent in the same time period and can be sent from multiple STAs (e.g., user STAs) having the AIDs indicated in the trigger frame 1030. The ACK frame 1050 for the TB PPDU can be implemented in various forms.

[0190] Refer to Figures 11 to 13 Describe the specific features of the trigger frame. Even when using UL-MU communication, an orthogonal frequency division multiple access (OFDMA) scheme or a MU MIMO scheme can be used, and the OFDMA and MU-MIMO schemes can be used simultaneously.

[0191] Fig.11 Shows an example of a trigger frame. Fig.11 The trigger frame allocates resources for uplink multi-user (MU) transmission and can be sent, for example, from an AP. The trigger frame can be configured by a MAC frame and can be included in a PPDU.

[0192] Fig.11 The respective fields shown can be partially omitted, and another field can be added. Additionally, the length of each field can be changed to be different from that shown in the figure.

[0193] Fig.11 The frame control field 1110 of can include information related to the MAC protocol version and additional control information. The duration field 1120 can include time information for NAV configuration or information related to the identifier of the STA (e.g., AID).

[0194] Additionally, the RA field 1130 may include the address information of the receiving STA of the corresponding trigger frame and may optionally be omitted. The TA field 1140 may include the address information of the STA (e.g., AP) that transmits the corresponding trigger frame. The common information field 1150 includes common control information applied to the receiving STA that receives the corresponding trigger frame. For example, it may include a field indicating the length of the L-SIG field of the uplink PPDU transmitted in response to the corresponding trigger frame or information for controlling the content of the SIG-A field (i.e., HE-SIG-A field) of the uplink PPDU transmitted in response to the corresponding trigger frame. Additionally, as common control information, it may include information related to the length of the CP of the uplink PPDU transmitted in response to the corresponding trigger frame or information related to the length of the LTF field.

[0195] Additionally, it is preferably included per-user information fields 1160#1 to 1160#N corresponding to the number of receiving STAs of the received Fig.11 trigger frame. The per-user information field may also be referred to as the "allocation field".

[0196] Additionally, Fig.11 the trigger frame may include a padding field 1170 and a frame check sequence field 1180.

[0197] Fig.11 Each of the per-user information fields 1160#1 to 1160#N shown may include a plurality of sub-fields.

[0198] Fig.12 An example of the common information field of the trigger frame is described. Fig.12 The sub-fields of may be partially omitted, and additional sub-fields may be added. Additionally, the lengths of the respective sub-fields shown may be changed.

[0199] The length field 1210 shown has the same value as the length field of the L-SIG field of the uplink PPDU transmitted in response to the corresponding trigger frame, and the length field of the L-SIG field of the uplink PPDU indicates the length of the uplink PPDU. As a result, the length field 1210 of the trigger frame can be used to indicate the length of the corresponding uplink PPDU.

[0200] Additionally, the concatenation identifier field 1220 indicates whether a concatenation operation is performed. The concatenation operation means that the downlink MU transmission and the uplink MU transmission are performed together in the same TXOP. That is, it means that the downlink MU transmission is performed, and then the uplink MU transmission is performed after a preset time (e.g., SIFS). During the concatenation operation, only one transmitting device (e.g., AP) can perform downlink communication, and multiple transmitting devices (e.g., non-APs) can perform uplink communication.

[0201] The CS request field 1230 indicates whether the wireless medium status or NAV, etc. must be considered when the receiving device that receives the corresponding trigger frame sends the corresponding uplink PPDU.

[0202] The HE-SIG-A information field 1240 may include information for controlling the content of the SIG-A field (i.e., the HE-SIG-A field) of the uplink PPDU in response to the corresponding trigger frame.

[0203] The CP and LTF type field 1250 may include information related to the CP length and LTF length of the uplink PPDU transmitted in response to the corresponding trigger frame. The trigger type field 1260 may indicate the purpose of using the corresponding trigger frame, such as a typical trigger, a trigger for beamforming, a request for block ACK / NACK, etc.

[0204] It may be assumed that the trigger type field 1260 of the trigger frame in this specification indicates a trigger frame of the basic type for a typical trigger. For example, a trigger frame of the basic type may be referred to as a basic trigger frame.

[0205] Fig.13 Describe an example of the subfield included in the per-user information field. Fig.13 The user information field 1300 may be understood as any one of the per-user information fields 1160#1 to 1160#N referred to above Fig.11 mentioned. The subfields included in Fig.13 the user information field 1300 may be partially omitted, and additional subfields may be added. In addition, the lengths of the respective shown subfields may be changed.

[0206] Fig.13 The user identifier field 1310 indicates the identifier of the STA (i.e., the receiving STA) corresponding to the per-user information. An example of the identifier may be all or part of the association identifier (AID) value of the receiving STA.

[0207] In addition, an RU allocation field 1320 may be included. That is, when the receiving STA identified by the user identifier field 1310 sends a TB PPDU in response to the trigger frame, the TB PPDU is sent through the RU indicated by the RU allocation field 1320. In this case, the RU indicated by the RU allocation field 1320 may be Figure 5 , Figure 6 and Figure 7 the RUs shown.

[0208] Fig.13The sub - fields may include a compilation type field 1330. The compilation type field 1330 may indicate the compilation type of the TB PPDU. For example, when BCC compilation is applied to the TB PPDU, the compilation type field 1330 may be set to "1", and when LDPC compilation is applied, the compilation type field 1330 may be set to "0".

[0209] In addition, Fig.13 The sub - fields may include an MCS field 1340. The MCS field 1340 may indicate the MCS scheme applied to the TB PPDU. For example, when BCC compilation is applied to the TB PPDU, the compilation type field 1330 may be set to "1", and when LDPC compilation is applied, the compilation type field 1330 may be set to "0".

[0210] Hereinafter, a random access (UORA) scheme based on UL OFDMA will be described.

[0211] Fig.14 Describe the technical features of the UORA scheme.

[0212] The transmitting STA (e.g., AP) may allocate six RU resources through a trigger frame as shown in Fig.14 . Specifically, the AP may allocate the 1st RU resource (AID 0, RU 1), the 2nd RU resource (AID 0, RU 2), the 3rd RU resource (AID 0, RU 3), the 4th RU resource (AID 2045, RU 4), the 5th RU resource (AID 2045, RU 5), and the 6th RU resource (AID 3, RU 6). Information related to AID 0, AID 3, or AID 2045 may be included in, for example, Fig.13 the user identifier field 1310. Information related to RU 1 to RU6 may be included in, for example, Fig.13 the RU allocation field 1320. AID = 0 may mean the UORA resources for the associated STA, and AID = 2045 may mean the UORA resources for the non - associated STA. Therefore, Fig.14 the 1st to 3rd RU resources of Fig.14 can be used as UORA resources for the associated STA, Fig.14 the 4th RU resource and the 5th RU resource of

[0213] In Fig.14In the example, the OFDMA random access backoff (OBO) of STA1 is reduced to 0, and STA1 randomly selects the 2nd RU resource (AID 0, RU 2). Additionally, since the OBO counters of STA2 / 3 are greater than 0, uplink resources are not allocated to STA2 / 3. Additionally, regarding Fig.14 STA4 in

[0214] Specifically, since Fig.14 STA1 of Fig.14 is an associated STA, the total number of eligible RA RUs for STA1 is 3 (RU1, RU 2, and RU 3). Therefore, STA1 decrements the OBO counter by 3 so that the OBO counter becomes 0. Additionally, since Fig.14 STA2 of

[0215] Fig.15 is an associated STA, the total number of eligible RA RUs for STA2 is 3 (RU 1, RU 2, and RU 3). Therefore, STA2 decrements the OBO counter by 3, but the OBO counter is greater than 0. Additionally, since

[0216] STA3 of

[0217] is a non-associated STA, the total number of eligible RA RUs for STA3 is 2 (RU 4, RU 5), and thus STA3 decrements the OBO counter by 2, but the OBO counter is greater than 0.

[0218] Fig.15 Examples of channels used / supported / defined within the 2.4 GHz band are described.

[0216] The 2.4 GHz band may be referred to by other terms such as the first band. Additionally, the 2.4 GHz band may refer to the frequency domain that uses / supports / defines channels with a center frequency close to 2.4 GHz (e.g., channels with a center frequency within 2.4 to 2.5 GHz).

[0217] Multiple 20 MHz channels may be included in the 2.4 GHz band. The 20 MHz within 2.4 GHz may have multiple channel indices (e.g., indices 1 to 14). For example, the center frequency of the 20 MHz channel assigned with channel index 1 may be 2.412 GHz, the center frequency of the 20 MHz channel assigned with channel index 2 may be 2.417 GHz, and the center frequency of the 20 MHz channel assigned with channel index N may be (2.407 + 0.005 * N) GHz. The channel index may be referred to by various terms such as channel number. The specific values of the channel index and the center frequency may vary.

[0218] Fig.15Four channels in the 2.4 GHz band are illustrated as examples. Each of the first frequency domain 1510 to the fourth frequency domain 1540 shown in this article may include one channel. For example, the first frequency domain 1510 may include Channel 1 (a 20 MHz channel with index 1). In this case, the center frequency of Channel 1 may be set to 2412 MHz. The second frequency domain 1520 may include Channel 6. In this case, the center frequency of Channel 6 may be set to 2437 MHz. The third frequency domain 1530 may include Channel 11. In this case, the center frequency of Channel 11 may be set to 2462 MHz. The fourth frequency domain 1540 may include Channel 14. In this case, the center frequency of Channel 14 may be set to 2484 MHz.

[0219] Fig.16 Examples of channels used / supported / defined within the 5 GHz band are described.

[0220] The 5 GHz band may be referred to by other terms such as the second band. The 5 GHz band may mean a frequency domain that uses / supports / defines channels with a center frequency greater than or equal to 5 GHz and less than 6 GHz (or less than 5.9 GHz). Alternatively, the 5 GHz band may include multiple channels between 4.5 GHz and 5.5 GHz. Fig.16 The specific values shown may be changed.

[0221] Multiple channels within the 5 GHz band include Unlicensed National Information Infrastructure (UNII)-1, UNII-2, UNII-3, and ISM. INII-1 may be referred to as UNII Low. UNII-2 may include frequency domains called UNII Mid and UNII-2 Extended. UNII-3 may be referred to as UNII-Upper.

[0222] Multiple channels may be configured within the 5 GHz band, and the bandwidth of each channel may be set differently, for example, to 20 MHz, 40 MHz, 80 MHz, 160 MHz, etc. For example, the frequency domain / range from 5170 MHz to 5330 MHz within UNII-1 and UNII-2 may be divided into eight 20 MHz channels. The frequency domain / range from 5170 MHz to 5330 MHz may be divided into four channels by a 40 MHz frequency domain. The frequency domain / range from 5170 MHz to 5330 MHz may be divided into two channels by an 80 MHz frequency domain. Alternatively, the frequency domain / range from 5170 MHz to 5330 MHz may be divided into one channel by a 160 MHz frequency domain.

[0223] Fig.17 Examples of channels used / supported / defined within the 6 GHz band are described.

[0224] The 6 GHz frequency band may be referred to as other terms such as a third frequency band, etc. The 6 GHz frequency band may mean a frequency domain that uses / supports / defines channels having a center frequency greater than or equal to 5.9 GHz. Fig.17 The specific values shown may be varied.

[0225] For example, Fig.17 The 20MHz channel can be defined starting from 5.940GHz. Fig.17 Among the 20 MHz channels of the channel, the leftmost channel may have an index of 1 (or a channel index, a channel number, etc.), and 5.945 GHz may be assigned as the center frequency. That is, the center frequency of the channel of index N may be determined to be (5.940+0.005*N) GHz.

[0226] therefore, Fig.17 The index (or channel number) of the 2MHz channel can be 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, 197, 201, 205, 209, 213, 217, 221, 225, 229, 233. In addition, according to the above (5.940+0.005*N)GHz rule, Fig.17 The index of the 40MHz channels 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.

[0227] Despite Fig.17 20, 40, 80, and 160 MHz channels are illustrated in the example of FIG. 1 , but a 240 MHz channel or a 320 MHz channel may be additionally added.

[0228] Hereinafter, a PPDU transmitted / received in a STA of the present specification will be described.

[0229] Fig.18 An example of PPDU used in this specification is described.

[0230] Fig.18The PPDU can be referred to by various terms such as an EHT PPDU, a TX PPDU, an RX PPDU, a first-type or an N-type PPDU. For example, in this specification, the PPDU or the EHT PPDU can be referred to by various terms such as a TX PPDU, an RX PPDU, a first-type or an N-type PPDU. Additionally, the EHT PPDU can be used in an EHT system and / or a new WLAN system enhanced from the EHT system.

[0231] Fig.18 The PPDU can indicate all or part of the PPDU type used in the EHT system. For example, Fig.18 The examples can be used for both the single-user (SU) mode and the multi-user (MU) mode. In other words, Fig.18 The PPDU can be a PPDU for one receiving STA or multiple receiving STAs. When Fig.18 The PPDU is used in the trigger-based (TB) mode, the Fig.18 EHT-SIG can be omitted. In other words, a STA that has received a trigger frame for uplink MU (UL-MU) can send a PPDU that omits the EHT-SIG in the Fig.18 example.

[0232] In Fig.18 , the L-STF to the EHT-LTF can be referred to as a preamble or a physical preamble, and can be generated / transmitted / received / obtained / decoded in the physical layer.

[0233] The Fig.18 subcarrier spacing of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-SIG fields can be determined to be 312.5 kHz, and the subcarrier spacing of the EHT-STF, EHT-LTF, and data fields can be determined to be 78.125 kHz. That is, the tone index (or subcarrier index) of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-SIG fields can be expressed in units of 312.5 kHz, and the tone index (or subcarrier index) of the EHT-STF, EHT-LTF, and data fields can be expressed in units of 78.125 kHz.

[0234] In Fig.18 the PPDU, the L-LTF and the L-STF can be the same as those in the conventional fields.

[0235] Fig.18The L-SIG field may include, for example, 24 bits of bit information. For example, the 24-bit 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 related to the length or duration of the PPDU. For example, the 12-bit length field may be determined based on the type of the PPDU. For example, when the PPDU is a non-HT, HT, VHT PPDU, or EHT PPDU, the value of the length field may be determined as a multiple of 3. For example, when the PPDU is a HE PPDU, the length field may be determined as "a multiple of 3"+1 or "a multiple of 3"+2. In other words, for a non-HT, HT, VHT PPDU, or EHT PPDU, the value of the length field may be determined as a multiple of 3, and for a HE PPDU, the value of the length field may be determined as "a multiple of 3"+1 or "a multiple of 3"+2.

[0236] For example, the transmitting STA may apply BCC coding with a 1 / 2 coding rate to the 24-bit information of the L-SIG field. Thereafter, the transmitting STA may obtain 48 bits of BCC-coded bits. BPSK modulation may be applied to the 48 coded bits, thereby generating 48 BPSK symbols. The transmitting STA may map the 48 BPSK symbols to positions other than the pilot subcarriers {subcarrier indices -21, -7, +7, +21} and the DC subcarrier {subcarrier index 0}. As a result, the 48 BPSK symbols may 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 may additionally map the signal of {-1, -1, -1, 1} to subcarrier indices {-28, -27, +27, +28}. The foregoing signal may be used for channel estimation in the frequency domain corresponding to {-28, -27, +27, +28}.

[0237] The transmitting STA may generate an RL-SIG generated in the same manner as the L-SIG. BPSK modulation may be applied to the RL-SIG. Based on the presence of the RL-SIG, the receiving STA may know that the RX PPDU is a HE PPDU or an EHT PPDU.

[0238] The Universal SIG (U-SIG) may be inserted after Fig.18 the RL-SIG. The U-SIG can be referred to by various terms 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, etc.

[0239] The U-SIG may include information of N bits and may include information for identifying the type of the EHT PPDU. For example, the U-SIG may be configured based on two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG may have a duration of 4 μs. Each symbol of the U-SIG may be used to transmit 26-bit information. For example, each symbol of the U-SIG may be transmitted / received based on 52 data tones and 4 pilot tones.

[0240] Through the U-SIG (or U-SIG field), for example, A-bit information (e.g., 52 unencoded bits) may be transmitted. The first symbol of the U-SIG may transmit the first X bits of the A-bit information (e.g., 26 unencoded bits), and the second symbol of the U-SIG may transmit the remaining Y bits of the A-bit information (e.g., 26 unencoded bits). For example, the transmitting STA may obtain 26 unencoded bits included in each U-SIG symbol. The transmitting STA may perform convolutional coding (i.e., BCC coding) at a rate of R = 1 / 2 to generate 52 encoded bits, and may perform interleaving on the 52 encoded bits. The transmitting STA may perform BPSK modulation on the interleaved 52 encoded bits to generate 52 BPSK symbols to be assigned to each U-SIG symbol. Except for the DC index 0, one U-SIG symbol may be transmitted based on 65 tones (subcarriers) from subcarrier index -28 to subcarrier index +28. The 52 BPSK symbols generated by the transmitting STA may be transmitted based on the remaining tones (subcarriers) except for the pilot tones, i.e., tones -21, -7, +7, +21.

[0241] For example, the A-bit information (e.g., 52 unencoded bits) generated by the U-SIG may include a CRC field (e.g., a field with a length of 4 bits) and a tail field (e.g., a field with a length of 6 bits). 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 the 26 bits assigned to the first symbol of the U-SIG and the remaining 16 bits in the second symbol except for the CRC / tail field, and may be generated based on a conventional CRC calculation algorithm. Additionally, the tail field may be used to terminate the trellis of the convolutional decoder and may be set to, for example, "000000".

[0242] The A-bit information (e.g., 52 unencoded bits) sent by the U-SIG (or U-SIG field) can be divided into version-independent bits and version-dependent bits. For example, the version-independent bits can have a fixed or variable size. 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 referred to in various terms such as the first control bit, the second control bit, etc.

[0243] For example, the version-independent bits of the U-SIG can include a 3-bit PHY version identifier. For example, the 3-bit PHY version identifier can include information related to the PHY version of the TX / RX PPDU. For example, the first value of the 3-bit PHY version identifier can indicate that the TX / RX PPDU is an EHT PPDU. In other words, when the transmitting STA sends an EHT PPDU, the 3-bit PHY version identifier can be set to the first value. In other words, the receiving STA can determine that the RX PPDU is an EHT PPDU based on the PHY version identifier having the first value.

[0244] For example, the version-independent bits of the U-SIG can include a 1-bit UL / DL flag field. The first value of the 1-bit UL / DL flag field is related to UL communication, and the second value of the UL / DL flag field is related to DL communication.

[0245] For example, the version-independent bits of the U-SIG can include information related to the TXOP length and information related to the BSS color ID.

[0246] For example, when an EHT PPDU is divided into various types (e.g., various types such as an EHT PPDU related to the SU mode, an EHT PPDU related to the MU mode, an EHT PPDU related to the TB mode, an EHT PPDU related to extended range transmission, etc.), the information related to the type of the EHT PPDU can be included in the version-dependent bits of the U-SIG.

[0247] For example, the U-SIG may include: 1) a bandwidth field including information related to bandwidth; 2) a field including information related to the MCS scheme applied to the EHT-SIG; 3) an indication field including information related to whether the dual sub-carrier modulation (DCM) scheme is applied to the EHT-SIG; 4) a field including information related to the number of symbols for the EHT-SIG; 5) a field including information related to whether the EHT-SIG is generated across the entire frequency band; 6) a field including information related to the type of the EHT-LTF / STF; and 7) information related to the fields indicating the EHT-LTF length and the CP length.

[0248] The preamble puncturing may be applied to the Fig.18 PPDU. The preamble puncturing implies that the puncturing is applied to a part of the entire frequency band (e.g., the secondary 20 MHz band). For example, when transmitting an 80 MHz PPDU, the STA may apply puncturing to the secondary 20 MHz band in the 80 MHz frequency band, and may transmit the PPDU only through the primary 20 MHz band and the secondary 40 MHz band.

[0249] For example, the pattern of the preamble puncturing may be pre-configured. For example, when the first puncturing pattern is applied, the puncturing may be applied only to the secondary 20 MHz band within the 80 MHz frequency band. For example, when the second puncturing pattern is applied, the puncturing may be applied only to any one of the two secondary 20 MHz bands included in the secondary 40 MHz band within the 80 MHz frequency band. For example, when the third puncturing pattern is applied, the puncturing may be applied only to the secondary 20 MHz band within the primary 80 MHz band included in the 160 MHz frequency band (or the 80 + 80 MHz frequency band). For example, when the fourth puncturing pattern is applied, the puncturing may be applied to at least one 20 MHz channel that does not belong to the primary 40 MHz band when the primary 40 MHz band exists in the 80 MHz frequency band included in the 160 MHz frequency band (or the 80 + 80 MHz frequency band).

[0250] The information related to the preamble puncturing applied to the PPDU may be included in the U-SIG and / or the EHT-SIG. For example, the first field of the U-SIG may include information related to the contiguous bandwidth, and the second field of the U-SIG may include information related to the preamble puncturing applied to the PPDU.

[0251] For example, based on the following method, U-SIG and EHT-SIG can include information related to preamble puncturing. When the bandwidth of the PPDU exceeds 80 MHz, the U-SIG can be configured individually in units of 80 MHz. For example, when the bandwidth of the PPDU is 160 MHz, the PPDU can 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 can include information related to the 160 MHz bandwidth, and the second field of the first U-SIG can include information related to the preamble puncturing applied to the first 80 MHz band (i.e., information related to the preamble puncturing pattern). Additionally, the first field of the second U-SIG can include information related to the 160 MHz bandwidth, and the second field of the second U-SIG can include information related to the preamble puncturing applied to the second 80 MHz band (i.e., information related to the preamble puncturing pattern). Meanwhile, the EHT-SIG consecutive to the first U-SIG can include information related to the preamble puncturing applied to the second 80 MHz band (i.e., information related to the preamble puncturing pattern), and the EHT-SIG consecutive to the second U-SIG can include information related to the preamble puncturing applied to the first 80 MHz band (i.e., information related to the preamble puncturing pattern).

[0252] Additionally or alternatively, based on the following method, U-SIG and EHT-SIG can include information related to preamble puncturing. The U-SIG can include information related to the preamble puncturing for all bands (i.e., information related to the preamble puncturing pattern). That is, the EHT-SIG may not include information related to preamble puncturing, and only the U-SIG can include information related to preamble puncturing (i.e., information related to the preamble puncturing pattern).

[0253] The U-SIG can be configured in units of 20 MHz. For example, when an 80 MHz PPDU is configured, the U-SIG can be replicated. That is, four identical U-SIGs can be included in the 80 MHz PPDU. A PPDU with a bandwidth exceeding 80 MHz can include different U-SIGs.

[0254] Fig.18 The EHT-SIG in [ ] can include control information for the receiving STA. The EHT-SIG can be transmitted through at least one symbol, and one symbol can have a length of 4 μs. Information related to the number of symbols for the EHT-SIG can be included in the U-SIG.

[0255] The EHT-SIG can include reference to Figure 8 and Fig. 9The technical features of the described HE-SIG-B. For example, the EHT-SIG may include common fields and user-specific fields as in the example of Figure 8 The common fields of the EHT-SIG can be omitted, and the number of user-specific fields can be determined based on the number of users.

[0256] As in the example of Figure 8 The common fields of the EHT-SIG and the user-specific fields of the EHT-SIG can be encoded separately. One user block field included in the user-specific fields can include information for two users, but the last user block field included in the user-specific fields can include information for one user. That is, one user block field of the EHT-SIG can include at most two user fields. As in the example of Fig. 9 Each user field can be related to MU-MIMO allocation or can be related to non-MU-MIMO allocation.

[0257] As in the example of Figure 8 The common fields of the EHT-SIG can include CRC bits and tail bits. The length of the CRC bits can be determined to be 4 bits. The length of the tail bits can be determined to be 6 bits and can be set to "000000".

[0258] As in the example of Figure 8 The common fields of the EHT-SIG can include RU allocation information. The RU allocation information can imply information related to the positions of the RUs to which multiple users (i.e., multiple receiving STAs) are allocated. The RU allocation information can be configured in units of 8 bits (or N bits), as shown in Table 1.

[0259] The examples of Tables 5 to 7 are examples of 8-bit (or N-bit) information for various RU allocations. The indexes shown in each table can be modified, some entries in Tables 5 to 7 can be omitted, and entries (not shown) can be added.

[0260] The examples of Tables 5 to 7 relate to information related to the positions of the RUs allocated to the 20 MHz band. For example, "Index 0" of Table 5 can be used in the case of separately allocating nine 26-RUs (e.g., in the case of separately allocating the nine 26-RUs shown in Figure 5 .

[0261] In addition, multiple RUs can be assigned to one STA in the EHT system. For example, regarding "Index 60" in Table 6, one 26-RU can be assigned to the leftmost user (i.e., the receiving STA) in the 20 MHz band, one 26-RU and one 52-RU can be assigned to its right, and five 26-RUs can be individually assigned to its right.

[0262] [Table 5]

[0263]

[0264] [Table 6]

[0265]

[0266] [Table 7]

[0267]

[0268] A mode that supports omitting the common fields of the EHT-SIG can be supported. The mode of omitting the common fields of the EHT-SIG can be referred to as the compression mode. When using the compression mode, multiple users (i.e., multiple receiving STAs) can decode the PPDU (e.g., the data field of the PPDU) based on non-OFDMA. That is, multiple users of the EHT PPDU can decode the PPDU (e.g., the data field of the PPDU) received through the same frequency band. In addition, when using the non-compression mode, multiple users of the EHT PPDU can decode the PPDU (e.g., the data field of the PPDU) based on OFDMA. That is, multiple users of the EHT PPDU can receive the PPDU (e.g., the data field of the PPDU) through different frequency bands.

[0269] The EHT-SIG can be configured based on various MCS schemes. As described above, information related to the MCS scheme applied to the EHT-SIG can be included in the U-SIG. The EHT-SIG can be configured based on the DCM scheme. For example, among the N data tones (e.g., 52 data tones) assigned to the EHT-SIG, the first modulation scheme can be applied to half of the consecutive tones, and the second modulation scheme can be applied to the remaining half of the consecutive tones. That is, the transmitting STA can use the first modulation scheme to modulate specific control information through the first symbol and assign it to half of the consecutive tones, and can use the second modulation scheme to modulate the same control information through the second symbol and assign it to the remaining half of the consecutive tones. As described above, information (e.g., a 1-bit field) regarding whether the DCM scheme is applied to the EHT-SIG can be included in the U-SIG.

[0270] Fig.18 The HE-STF can be used to improve automatic gain control estimation in a multiple-input multiple-output (MIMO) environment or an OFDMA environment. Fig.18 The HE-LTF can be used to estimate a channel in a MIMO environment or an OFDMA environment.

[0271] It can be set in various types Fig.18 The EHT-STF. For example, a first type of STF (e.g., 1x STF) can be generated based on a first type of STF sequence in which non-zero coefficients are arranged at intervals of 16 subcarriers. The STF signal generated based on the first type of STF sequence can have a period of 0.8 μs, and the 0.8 μs period signal can be repeated 5 times to become a first type of STF with a length of 4 μs. For example, a second type of STF (e.g., 2x STF) can be generated based on a second type of STF sequence in which non-zero coefficients are arranged at intervals of 8 subcarriers. The STF signal generated based on the second type of STF sequence can have a period of 1.6 μs, and the 1.6 μs period signal can be repeated 5 times to become a second type of STF with a length of 8 μs. Hereinafter, examples of sequences for configuring the EHT-STF (i.e., EHT-STF sequences) are presented. The following sequences can be modified in various ways.

[0272] The EHT-STF can be configured based on the following sequence M.

[0273] <Equation 1>

[0274] M = {–1, –1, –1, 1, 1, 1, –1, 1, 1, 1, –1, 1, 1, –1, 1}

[0275] The EHT-STF for a 20 MHz PPDU can be configured based on the following equation. The following example can be a first type (i.e., 1xSTF) sequence. For example, the first type of sequence can be included in an EHT-PPDU rather than a trigger-based (TB) PPDU. In the following equation, (a:b:c) can imply a duration defined as b tone intervals (i.e., subcarrier intervals) from a tone index (i.e., subcarrier index) 'a' to a tone index 'c'. For example, the following Equation 2 can represent a sequence defined as 16 tone intervals from tone index -112 to tone index 112. Since a subcarrier interval of 78.125 kHz is applied to the EHT-STR, 16 tone intervals can imply that the EHT-STF coefficients (or elements) are arranged at intervals of 78.125 * 16 = 1250 kHz. Additionally, * implies multiplication, and sqrt() implies the square root. Additionally, j implies an imaginary number.

[0276] <Equation 2>

[0277] EHT-STF(-112:16:112) = {M}*(1 + j) / sqrt(2)

[0278] EHT-STF(0) = 0

[0279] The EHT-STF for a 40 MHz PPDU can be configured based on the following equation. The following example can be a first type (i.e., 1x STF) sequence.

[0280] <Equation 3>

[0281] EHT-STF(-240:16:240) = {M, 0, -M}*(1 + j) / sqrt(2)

[0282] The EHT-STF for an 80 MHz PPDU can be configured based on the following equation. The following example can be a first type (i.e., 1x STF) sequence.

[0283] <Equation 4>

[0284] EHT-STF(-496:16:496) = {M, 1, –M, 0, –M, 1, –M}*(1 + j) / sqrt(2)

[0285] The EHT-STF for a 160 MHz PPDU can be configured based on the following equation. The following example can be a first type (i.e., 1x STF) sequence.

[0286] <Equation 5>

[0287] EHT-STF(-1008:16:1008) = {M, 1, –M, 0, –M, 1, –M, 0, –M, –1, M, 0, –M, 1, –M}*(1 + j) / sqrt(2)

[0288] In the EHT-STF for an 80 + 80 MHz PPDU, the sequence for the lower 80 MHz can be the same as Equation 4. In the EHT-STF for an 80 + 80 MHz PPDU, the sequence for the upper 80 MHz can be configured based on the following equation.

[0289] <Equation 6>

[0290] EHT-STF(-496:16:496) = {-M, -1, M, 0, –M, 1, –M}*(1 + j) / sqrt(2)

[0291] The following equations 7 to 11 are related to examples of a second type (i.e., 2x STF) sequence.

[0292] <Equation 7>

[0293] EHT-STF(-120:8:120) = {M, 0, -M} * (1 + j) / sqrt(2)

[0294] The EHT-STF for a 40 MHz PPDU can be configured based on the following equation.

[0295] <Equation 8>

[0296] EHT-STF(-248:8:248) = {M, –1, –M, 0, M, –1, M} * (1 + j) / sqrt(2)

[0297] EHT-STF(-248) = 0

[0298] EHT-STF(248) = 0

[0299] The EHT-STF for an 80 MHz PPDU can be configured based on the following equation.

[0300] <Equation 9>

[0301] EHT-STF(-504:8:504) = {M, –1, M, –1, –M, –1, M, 0, –M, 1, M, 1, –M, 1, –M} * (1 + j) / sqrt(2)

[0302] The EHT-STF for a 160 MHz PPDU can be configured based on the following equation.

[0303] <Equation 10>

[0304] EHT-STF(-1016:16:1016) = {M, –1, M, –1, –M, –1, M, 0, –M, 1, M, 1, –M, 1, –M, 0, –M, 1, –M, 1, M, 1, –M, 0, –M, 1, M, 1, –M, 1, –M} * (1 + j) / sqrt(2)

[0305] EHT-STF(-8) = 0, EHT-STF(8) = 0,

[0306] EHT-STF(-1016) = 0, EHT-STF(1016) = 0

[0307] In the EHT-STF for an 80 + 80 MHz PPDU, the sequence for the lower 80 MHz can be the same as Equation 9. In the EHT-STF for an 80 + 80 MHz PPDU, the sequence for the higher 80 MHz can be configured based on the following equation.

[0308] <Equation 11>

[0309] EHT-STF(-504:8:504) = {–M,1,–M,1,M,1,–M,0,–M,1,M,1,–M,1,–M}*(1 + j) / sqrt(2)

[0310] EHT-STF(-504) = 0,

[0311] EHT-STF(504) = 0

[0312] EHT-LTF can have first, second, and third types (i.e., 1x, 2x, 4x LTF). For example, the first / second / third type LTF can be generated based on an LTF sequence in which non-zero coefficients are arranged at intervals of 4 / 2 / 1 subcarriers. The first / second / third type LTF can have a time length of 3.2 / 6.4 / 12.8 μs. Additionally, GIs of various lengths (e.g., 0.8 / 1 / 6 / 3.2 μs) can be applied to the first / second / third type LTF.

[0313] Information related to the type of STF and / or LTF (including information related to the GI applied to the LTF) can be included in Fig.18 the SIG-A field and / or SIG-B field, etc.

[0314] It can be configured based on Figure 5 and Figure 6 examples of Fig.18 the PPDU (e.g., EHT-PPDU).

[0315] For example, the EHT PPDU transmitted on a 20 MHz frequency band, i.e., 20 MHz EHT PPDU, can be configured based on Figure 5 the RU of Figure 5 That is, the positions of the RUs of the EHT-STF, EHT-LTF, and data fields included in the EHT PPDU can be determined as shown in

[0316] The EHT PPDU transmitted on a 40 MHz frequency band, i.e., 40 MHz EHT PPDU, can be configured based on Figure 6 the RU of Figure 6 That is, the positions of the RUs of the EHT-STF, EHT-LTF, and data fields included in the EHT PPDU can be determined as shown in

[0317] Since Figure 6 the RU position of Figure 6 corresponds to 40 MHz, the tone-plan for 80 MHz can be determined when the pattern of Figure 7 is repeated twice. That is, it can be based on where instead of the RU of Figure 6 A new tone plan with the RU repeated twice is used to send 80 MHz EHT PPDU.

[0318] When Figure 6 the pattern is repeated twice, 23 tones can be configured in the DC region (i.e., 11 guard tones + 12 guard tones). That is to say, the tone plan for the 80 MHz EHT PPDU based on OFDMA allocation can have 23 DC tones. In contrast, the 80 MHz EHT PPDU based on non-OFDMA allocation (i.e., non-OFDMA full bandwidth 80 MHz PPDU) can be configured based on 996-RU and can include 5 DC tones, 12 left guard tones, and 11 right guard tones.

[0319] It is possible to configure the tone plan for 160 / 240 / 320 MHz in such a way that Figure 6 the pattern is repeated several times.

[0320] The Fig.18 PPDU can be determined (or identified) as an EHT PPDU based on the following method.

[0321] The receiving STA can determine the type of the RX PPDU as an EHT PPDU based on the following aspects. For example, 1) when the first symbol after the L-LTF signal of the RX PPDU is a BPSK symbol; 2) when an RL-SIG in which the L-SIG of the RX PPDU is repeated is detected; and 3) when the result of applying "mod 3" to the value of the length field of the L-SIG of the RX PPDU is "0", the RX PPDU can be determined as an EHT PPDU. When the RX PPDU is determined as an EHT PPDU, the receiving STA can detect the type of the EHT PPDU (e.g., SU / MU / trigger-based / extended range type) based on the bit information included in the symbols after the Fig.18 RL-SIG of. In other words, the receiving STA can determine the RX PPDU as an EHT PPDU based on the following: 1) the first symbol after the L-LTF signal, which is a BPSK symbol; 2) the RL-SIG that is consecutive with and the same as the L-SIG field; 3) the L-SIG including the length field, where the result of applying "mod 3" is set to "0"; and 4) the 3-bit PHY version identifier of the aforementioned U-SIG (e.g., the PHY version identifier with the first value).

[0322] For example, a receiving STA may determine the type of an RX PPDU as an EHT PPDU based on the following aspects. For example, 1) when the first symbol after the L-LTF signal is a BPSK symbol; 2) when an RL-SIG in which the L-SIG is repeated is detected; and 3) when the result of applying "mod 3" to the value of the length field of the L-SIG is detected to be "1" or "2", the RX PPDU may be determined as a HEPPDU.

[0323] For example, a receiving STA may determine the type of an RX PPDU as a non-HT, HT, and VHT PPDU based on the following aspects. For example, 1) when the first symbol after the L-LTF signal is a BPSK symbol; and 2) when an RL-SIG in which the L-SIG is repeated is not detected, the RX PPDU may be determined as a non-HT, HT, and VHT PPDU. Additionally, even when the receiving STA detects an RL-SIG repetition, when the result of applying "mod 3" to the length value of the L-SIG is detected to be "0", the RX PPDU may also be determined as a non-HT, HT, and VHT PPDU.

[0324] In the following examples, signals represented as (TX / RX / UL / DL) signals, (TX / RX / UL / DL) frames, (TX / RX / UL / DL) packets, (TX / RX / UL / DL) data units, (TX / RX / UL / DL) data, etc. may be signals transmitted / received based on Fig.18 the PPDU. Fig.18 The PPDU of Fig.18 may be used to transmit / receive various types of frames. For example, Fig.18 the PPDU of Fig.18 may be used for control frames. Examples of control frames may include Request to Send (RTS), Clear to Send (CTS), Power Save Poll (PS-poll), BlockACKReq, BlockAck, Null Data Packet (NDP) Announcement, and Trigger frames. For example, Fig.18 the PPDU of

[0325] Fig.19 Examples of the transmitting device and / or receiving device that modify this specification.

[0326] Figure 1 Each device / STA in subgraph (a) / (b) of Fig.19 may be modified as shown. Fig.19 The transceiver 630 of Figure 1 can be the same as the transceivers 113 and 123 of Fig.19 The transceiver 630 of

[0327] Fig.19 The processor 610 of Figure 1 can be the same as the processors 111 and 121 of Fig.19 Alternatively, the processor 610 of Figure 1 can be the same as the processing chips 114 and 124 of

[0328] Fig.19 The memory 620 of Figure 1 can be the same as the memories 112 and 122 of Fig.19 Alternatively, the memory 620 of Figure 1 can be a separate external memory different from the memories 112 and 122 of

[0329] Referring to Fig.19 , the power management module 611 manages the power for the processor 610 and / or the transceiver 630. The battery 612 supplies power to the power management module 611. The display 613 outputs the results processed by the processor 610. The keypad 614 receives the inputs to be used by the processor 610. The keypad 614 can be displayed on the display 613. The SIM card 615 can be an integrated circuit for securely storing the International Mobile Subscriber Identity (IMSI) and its related keys, which is used to identify and authenticate users on mobile phone devices (such as mobile phones and computers).

[0330] Referring to Fig.19 , the speaker 640 can output the results related to the sound processed by the processor 610. The microphone 641 can receive the inputs related to the sound to be used by the processor 610.

[0331] Fig. 20 An example of a HE-PPDU is shown.

[0332] The L-STF 2000 shown can include short training Orthogonal Frequency Division Multiplexing (OFDM) symbols. The L-STF 2000 can be used for frame detection, Automatic Gain Control (AGC), diversity detection, and coarse frequency / time synchronization.

[0333] The L-LTF 2010 can include long training Orthogonal Frequency Division Multiplexing (OFDM) symbols. The L-LTF 2010 can be used for fine frequency / time synchronization and channel estimation.

[0334] L-SIG 2020 can be used to send control information. L-SIG 2020 can include information related to data transfer rate and data length. Additionally, L-SIG 2020 can be sent repeatedly. That is, L-SIG 2020 can be configured in a repetitive format (e.g., it can be referred to as R-LSIG).

[0335] HE-SIG-A 2030 can include control information common to receiving stations.

[0336] Specifically, HE-SIG-A 2030 can include information related to: 1) DL / UL indicator; 2) BSS color field as an identifier of the BSS; 3) field indicating the remaining time of the current TXOP duration / cycle; 4) bandwidth field indicating whether it is 20, 40, 80, 160, or 80+80 MHz; 5) field indicating the MCS scheme applied to HE-SIG-B; 6) indication field indicating whether modulation dual subcarrier modulation (DCM) is applied to the MCS of HE-SIG-B; 7) field indicating the number of symbols for HE-SIG-B; 8) field indicating whether HE-SIG-B is generated over the entire / full frequency band; 9) field indicating the number of symbols of HE-LTF; 10) field indicating the length of HE-LTF and the CP length; 11) field indicating whether there are additional OFDM symbols for LDPC encoding; 12) field indicating control information regarding packet extension (PE); and / or 13) field indicating information related to the CRC field of HE-SIG-A, etc. At least one field of HE-SIG-A can be omitted or changed. Additionally, in other environments where HE-SIG-A is not a multi-user (MU) environment, some fields can be added or omitted.

[0337] Additionally, HE-SIG-A 2030 can consist of two parts: HE-SIG-A1 and HE-SIG-A2. HE-SIG-A1 and HE-SIG-A2 included in HE-SIG-A can be defined according to the following format structure (fields) for the corresponding PPDU. First, the HE-SIG-A field of the HE SUPPDU can be defined as follows.

[0338] [Table 8]

[0339]

[0340] [Table 9]

[0341]

[0342] [Table 10]

[0343]

[0344] [Table 11]

[0345]

[0346] In addition, the HE-SIG-A field of the HE MU PPDU can be defined as follows.

[0347] [Table 12]

[0348]

[0349] [Table 13]

[0350]

[0351]

[0352] [Table 14]

[0353]

[0354] [Table 15]

[0355]

[0356]

[0357] In addition, the HE-SIG-A field of the HE TB PPDU can be defined as follows.

[0358] [Table 16]

[0359]

[0360] [Table 17]

[0361]

[0362] [Table 18]

[0363]

[0364] [Table 19]

[0365]

[0366] [Table 20]

[0367]

[0368] As described above, the HE-SIG-B 2040 may be included only for a multi-user (MU) PPDU. Basically, the HE-SIG-A 2050 or the HE-SIG-B 2060 may include resource allocation information (or virtual resource allocation information) for at least one receiving STA.

[0369] Hereinafter, technical features of channel bonding supported by the STA of the present disclosure will be described.

[0370] For example, in an IEEE 802.11n system, 40 MHz channel bonding may be performed by combining two 20 MHz channels. In addition, 40 / 80 / 160 MHz channel bonding may be performed in an IEEE 802.11ac system.

[0371] For example, the STA may perform channel bonding on a primary 20 MHz channel (P20 channel) and a secondary 20 MHz channel (S20 channel). A backoff count / counter may be used during the channel bonding process. The backoff count value may be selected as a random value and decremented during the backoff interval. Generally, when the backoff count value becomes 0, the STA may attempt to access the channel.

[0372] During the backoff interval, when it is determined that the P20 channel is in an idle state and the backoff count value of the P20 channel becomes 0, the STA performing channel bonding determines whether the S20 channel remains idle within a certain period (e.g., point coordination function inter-frame space (PIFS)). If the S20 channel is in an idle state, the STA may perform bonding on the P20 channel and the S20 channel. That is, the STA may transmit a signal (PPDU) through a 40 MHz channel (i.e., a 40 MHz bonded channel) including the P20 channel and the S20 channel.

[0373] Fig.21 An example of channel bonding is shown. As Fig.21 shown, the primary 20 MHz channel and the secondary 20 MHz channel are configured as a primary 40 MHz channel through channel bonding. That is, the bonded 40 MHz channel may include the primary 20 MHz channel and the secondary 20 MHz channel.

[0374] Channel bonding may be performed when a channel adjacent to the primary channel is in an idle state. That is, the primary 20 MHz channel, the secondary 20 MHz channel, the secondary 40 MHz channel, and the secondary 80 MHz channel may be sequentially bonded. However, when it is determined that the secondary 20 MHz channel is busy, channel bonding may not be performed even if all other secondary channels are in an idle state. In addition, when it is determined that the secondary 20 MHz channel is in an idle state and it is determined that the secondary 40 MHz channel is busy, channel bonding may be performed only on the primary 20 MHz channel and the secondary 20 MHz channel.

[0375] In the following, the preamble puncturing supported by the station (STA) of this specification will be described.

[0376] For example, in Fig.21 the example of, when the primary 20 MHz channel, the secondary 40 MHz channel, and the secondary 80 MHz channel are all idle, while the secondary 20 MHz channel is busy, bundling between the secondary 40 MHz channel and the secondary 80 MHz channel may not be possible. In this case, the STA can configure a 160 MHz PPDU and puncture the preamble (e.g., L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF, EHT-SIG, EHT-STF, EHT-LTF, etc.) transmitted through the secondary 20 MHz channel (or perform preamble puncturing on the preamble), so as to be able to transmit signals through the idle channels. In other words, the STA can perform preamble puncturing on a partial frequency band of the PPDU. Information about the preamble puncturing (e.g., information about the 20 / 40 / 80 MHz channel / frequency band where puncturing is applied) can be included in the signal field (e.g., HE-SIG-A, U-SIG, EHT-SIG) of the PPDU.

[0377] In the following, the technical features of the multi-link (ML) supported by the STA of this disclosure will be described.

[0378] The STA (AP and / or non-AP STA) of this disclosure can support multi-link (ML) communication. ML communication can refer to communication that supports multiple links. The links related to ML communication can include Fig.15 the 2.4 GHz frequency band shown in Fig.16 the 5 GHz frequency band shown in Fig.17 and the channels (e.g., 20 / 40 / 80 / 160 / 240 / 320 MHz channels) in the 6 GHz frequency band shown in

[0379] The multiple links for ML communication can be set in various ways. For example, the multiple links for ML communication supported by one STA can be multiple channels in the 2.4 GHz frequency band, multiple channels in the 5 GHz frequency band, and multiple channels in the 6 GHz frequency band. Alternatively, the multiple links for ML communication supported by one STA can be a combination of at least one channel in the 2.4 GHz frequency band (or 5 GHz / 6 GHz frequency band) and at least one channel in the 5 GHz frequency band (or 2.4 GHz / 6 GHz frequency band). At the same time, at least one of the multiple links for ML communication supported by one STA can be a channel to which preamble puncturing is applied.

[0380] The STA can perform ML establishment to execute ML communication. The ML establishment can be performed based on management frames or control frames such as beacons, probe requests / responses, association requests / responses, etc. For example, information regarding ML establishment can be included in the element fields included in beacons, probe requests / responses, association requests / responses, etc.

[0381] When the ML establishment is completed, an enabled link for ML communication can be determined. The STA can perform frame exchange through at least one of the multiple links determined to be the enabled link. For example, the enabled link can be used for at least one of management frames, control frames, and data frames.

[0382] When a STA supports multiple links, the transceivers supporting each link can operate as a single logical STA. For example, a STA supporting two links can be expressed as a multi-link device (MLD), which includes a first STA for the first link and a second STA for the second link. For example, an AP supporting two links can be expressed as an AP MLD, which includes a first AP for the first link and a second AP for the second link. Additionally, a non-AP supporting two links can be expressed as a non-AP MLD, which includes a first STA for the first link and a second STA for the second link.

[0383] Hereinafter, more specific features related to ML establishment will be described.

[0384] The MLD (AP MLD and / or non-AP MLD) can send information about the links that the corresponding MLD can support through ML establishment. The link information can be configured in various ways. For example, the information about the link can include at least one of the following: 1) information about whether the MLD (or STA) supports simultaneous RX / TX operations, 2) information about the number / upper limit of uplink / downlink supported by the MLD (or STA), 3) information about the location / band / resource of the uplink / downlink supported by the MLD (or STA), 4) information about the frame types (management, control, data, etc.) available or preferred in at least one uplink / downlink, 5) ACK policy information available or preferred in at least one uplink / downlink, and 6) information about the traffic identifier (TID) available or preferred in at least one uplink / downlink. The TID is related to the priority of traffic data and is expressed as eight types of values according to the traditional wireless LAN standard. That is, eight TID values can be defined corresponding to the four access categories (AC) (AC_BK (background), AC_BE (best effort), AC_VI (video), AC_VO (voice)) according to the traditional WLAN standard.

[0385] For example, all TIDs can be pre-configured to be mapped for uplink / downlink. Specifically, when no negotiation is performed through ML establishment, all TIDs are used for ML communication. If the mapping between uplink / downlink and TIDs is negotiated through additional ML settings, the negotiated TIDs can be used for ML communication.

[0386] Multiple links available for transmitting MLD and receiving MLD related to ML communication can be configured through ML establishment, and this can be referred to as "enabling a link". "Enabling a link" can be differently named with various expressions. For example, it can be referred to by various terms such as a first link, a second link, a transmission link, and a receiving link.

[0387] After ML establishment is completed, the MLD can update the ML establishment. For example, when it is necessary to update information about the link, the MLD can send information about the new link. Information about the new link can be sent based on at least one of a management frame, a control frame, and a data frame.

[0388] According to an embodiment, the MLD can include a non-AP MLD and an AP-MLD. The non-AP MLD and the AP-MLD can be classified according to the functions of an access point (AP). The non-AP MLD and the AP-MLD can be physically separated or logically separated. For example, when the MLD performs AP functions, it can be referred to as an AP MLD, and when the MLD performs STA functions, it can be referred to as a non-AP MLD.

[0389] Hereinafter, in this specification, the MLD has one or more STAs connected thereto and one MAC service access point (SAP) connected to the logical link control (LLC). The MLD can refer to a physical device or a logical device. Hereinafter, the term device can refer to the MLD.

[0390] In addition, the MLD can include at least one STA connected to each link in the multi-link. For example, the processor of the MLD can control at least one STA. For example, at least one STA can be independently configured and can operate independently. At least one STA can each include a processor and a transceiver. For example, regardless of the processor of the MLD, at least one STA can operate independently.

[0391] Hereinafter, for simplicity of description, it will be described in the present disclosure that the MLD (or the processor of the MLD) controls at least one STA. However, the present disclosure is not limited thereto. As described above, regardless of the MLD, at least one STA can independently transmit and / or receive signals.

[0392] According to an embodiment, an AP MLD or a non-AP MLD may be configured to have a structure including multiple links. In other words, the non-AP MLD may support multiple links. The non-AP MLD may include multiple STAs. Multiple STAs may each have one link per STA.

[0393] The EHT specification (802.11be specification) regards the multi-link device (MLD) structure in which one AP / non-AP MLD supports multiple links as a major technology. The STAs included in the non-AP MLD may transmit (or transfer) information about other STAs within the non-AP MLD together through one link. Therefore, this has the effect of reducing the overhead of frame exchange. In addition, this also has the effects of increasing the link usage efficiency and reducing the power consumption of the STAs.

[0394] Fig. 22 An exemplary structure of the non-AP MLD is shown.

[0395] Referring to Fig. 22 , the non-AP MLD may be configured to have a structure including multiple links. In other words, the non-AP MLD may support multiple links. The non-AP MLD may include multiple STAs. Multiple STAs may each have one link per STA. Although Fig. 22 an exemplary structure of the non-AP MLD is shown, the structure of the AP MLD may also be configured in the same way as the non-AP MLD structure shown in Fig. 22 .

[0396] For example, the non-AP MLD may include STA 1, STA 2, and STA 3. STA 1 may operate on Link 1. Link 1 may be included in the 5 GHz band. STA 2 may operate on Link 2. Link 2 may be included in the 6 GHz band. STA 3 may operate on Link 3. Link 3 may be included in the 5 GHz band. The bands including Link 1 / 2 / 3 are only exemplary. Therefore, the links may also be included in 2.4, 5, and 6 GHz.

[0397] As described above, in the case of an AP / non-AP MLD supporting multiple links, each AP of the AP MLD and each STA of the non-AP MLD may be connected to each link through a link establishment process. And, depending on the situation, the links connected at this time may be switched or reconnected to another link through the AP MLD or the non-AP MLD.

[0398] In addition, in the EHT specification, in order to reduce power consumption, a link may be divided into an anchored link and an unanchored link. The anchored link or the unanchored link may be referred to by various terms. For example, the anchored link may be referred to as the primary link. And, the unanchored link may be referred to as the secondary link.

[0399] According to an embodiment, an AP MLD supporting multiple links can manage the links by designating each link as an anchor link or a non-anchor link. The AP MLD can support one or more of the multiple links as anchor links. A non-AP MLD can use the anchor link by selecting one or more of its anchor links from the anchor link list (i.e., the list of anchor links supported by the AP MLD).

[0400] For example, the anchor link can be used not only for frame exchange for synchronization but also for non-data frame exchange (i.e., beacons and management frames). In addition, the non-anchor link can be used only for data frame exchange.

[0401] During the idle period, the non-AP MLD can perform monitoring only on the anchor link (or monitor only the anchor link) to receive beacons and management frames. Therefore, in the case of the non-AP MLD, the non-AP MLD should be connected to at least one anchor link to receive beacons and management frames. One or more anchor links should always be maintained in an enabled state. In contrast, the non-anchor link is used only for data frame exchange. Therefore, the STA corresponding to the non-anchor link (or the STA connected to the non-anchor link) can enter the doze mode during the idle period when the channel / link is not in use. By doing so, this has the effect of reducing power consumption.

[0402] Hereinafter, a protocol can be proposed that enables the AP MLD or the non-AP MLD to dynamically recommend or request link reconnection according to the situation for efficient link connection. In addition, hereinafter, in this specification, an anchor link reconnection protocol based on the anchor link can be additionally proposed, which is used not only as a general link but also for power reduction purposes.

[0403] Implementation of link switching and reconnection

[0404] According to an embodiment, each link between the AP MLD and the non-AP MLD can be determined during the association or (re)association process. The AP MLD and the non-AP MLD can perform frame exchange through the link connected at this time. For the detailed embodiments of the AP MLD and the non-AP MLD connected through the link establishment process, reference can be made to Fig.23 Description.

[0405] Fig.23 Illustrate an exemplary connection between the AP MLD and the non-AP MLD through the link establishment process.

[0406] Refer to Fig.23, the AP MLD may include APs 1, 2, and 3. Also, the non-AP MLD may include STAs 1 and 2. AP 1 and STA 1 may be connected via Link 1. Also, AP 2 and STA 2 may be connected via Link 2.

[0407] For example, AP 1 and STA 1 may be connected via Link 1 through a first link establishment process. AP 2 and STA 2 may be connected via Link 2 through a second link establishment process. As another example, the AP MLD and the non-AP MLD may be connected through a single link establishment process. In other words, the AP MLD and the non-AP MLD may be connected via Link 1 and Link 2 based on a single link establishment process.

[0408] As described above, each AP and STA may perform frame exchange via the link to which it is connected. Additionally, information about other links related to other APs or information about other links related to other STAs may be sent and / or received via one link.

[0409] However, after performing the above link establishment process, for more efficient frame exchange according to the situation / environment (e.g., load balancing or interference avoidance, etc.), the AP MLD or the non-AP MLD may request link switching or reconnection.

[0410] Reference may be made to Fig.24 to describe embodiments related to link switching or reconnection.

[0411] Fig.24 An example where the link is switched or reconnected is shown.

[0412] Reference is made to Fig.24 , in the existing structure, STA 2 is connected to AP 2. Thereafter, the data load of AP 2 may become too large. Therefore, STA 2 may reconnect to AP 3 with a relatively smaller data load. In this case, this has the effect of enabling the AP MLD and the non-AP MLD to perform efficient data exchange.

[0413] Fig.25 A detailed example where the link is switched or reconnected is shown.

[0414] Reference is made to Fig.25 , AP 1 of the AP MLD may be connected to STA 1 of the non-AP MLD via Link 1. AP 2 of the AP MLD may be connected to STA 2 of the non-AP MLD via Link 2. Thereafter, STA 2 may attempt / request to connect to AP 3 through link switching or reconnection, and STA 2 may be connected to AP 3 via Link 2 based on the link switching or reconnection.

[0415] According to an embodiment, the AP MLD and the non-AP MLD can transmit and receive (or send and / or receive) / exchange various information per current link and information related to the link state. Therefore, the AP MLD and the non-AP MLD can select a link that is more suitable (or sufficient) for sending and / or receiving signals based on the various information per current link and the information related to the link state. For example, the various information per current link can include information about the per-link data traffic load and information about the channel access capabilities between the links. For example, the link state can be configured to be disabled or enabled, etc.

[0416] Hereinafter, in this specification, the process in which the AP MLD / non-AP MLD negotiates with the non-AP MLD / AP MLD to request a handover or reconnection to a link other than the initially connected link to increase its performance can be referred to as "link handover negotiation". The term "link handover negotiation" can also be referred to by many other terms, and thus, the term can also change.

[0417] Hereinafter, the link handover or reconnection process can be described by dividing it into cases where the AP MLD requests the process and cases where the non-AP MLD requests the process.

[0418] Implementation Method of AP MLD Requesting Link Switching or Reconnection

[0419] According to an embodiment, for efficient data transmission, the AP MLD can request a link handover or reconnection to the non-AP MLD. For example, for load balancing, the AP MLD can request the STA to handover or reconnect its link to a more efficient link based on the data traffic of each AP.

[0420] For example, the AP MLD can calculate / verify / confirm (or finalize) a link suitable for the STA of the non-AP MLD based on the per-AP data traffic load information and / or the channel access capability information between the respective links (for example, information related to the simultaneous TX / RX (STR) capability, etc.). Thereafter, the AP MLD can request the STA (or non-AP MLD) link handover or reconnection based on the per-AP data traffic load information and / or the channel access capability information between the respective links.

[0421] As described above, when requesting a link handover, the AP MLD can send information about the link considered to be the most suitable link to the AP MLD through a request message. For example, the request message can include a beacon or a management frame, etc.

[0422] Regarding the above-described embodiments, elements or fields including link information regarding the link considered to be the most suitable can be newly proposed. The newly proposed elements or fields can be defined as "recommended link". The term "recommended link" is merely exemplary, and thus, the detailed terms of the elements or fields can be changed.

[0423] Recommended links (element / field) : This is an element or field that enables the AP MLD to recommend a link to the STA that is most suitable for the non-AP MLD based on various information per link (e.g., per-link data load, etc.). For example, the recommended link (element / field) can be indicated as the link ID information of the AP MLD or the AP BSS information, etc. In other words, the recommended link (element / field) can include the link ID information of the AP MLD or the AP BSS information, etc.

[0424] According to an embodiment, the recommended link (element / field) can be optionally included in the link switch response and then sent. For example, the STA can establish a connection to the link recommended by the AP based on the corresponding element / field (i.e., the recommended link). As another example, the STA can also perform a connection request to a link other than the indicated link based on the corresponding element / field (i.e., the recommended link) and additional information that the STA has (or owns).

[0425] The detailed signal exchange process between the AP MLD and the non-AP MLD according to the above-described embodiments can be referred to Fig.26 for description.

[0426] Fig.26 illustrates the operations of the AP MLD and the non-AP MLD for link switching or reconnection.

[0427] Referring to Fig.26 , in the case where the STA 2 is connected to the AP 2 via link 2, a large amount of data traffic may be concentrated on the AP2. In other words, in the case where the STA 2 is connected to the AP 2 via link 2, a relatively large amount of data traffic may occur in the AP 2.

[0428] The AP MLD (or AP 2) can request the non-AP MLD (or STA 2) to reconnect to the AP 3 with a relatively smaller number of STA connections. Generally, a message for requesting reconnection is sent to the STA that wants to reconnect (i.e., STA 2). However, depending on the situation (e.g., channel situation or link state), the message can also be sent to any STA (i.e., other STAs). In other words, the STA to which the request message for requesting reconnection (e.g., link switch request frame) is sent can change.

[0429] For example, when a STA (i.e., STA 2) that has received a request message for requesting reconnection accepts the request, the STA may send a response message "Accepted" (e.g., a link switch response frame). As another example, if the STA (i.e., STA 2) rejects (or refuses) the request, the STA may send a response message "Rejected".

[0430] In the case of the response message, the STA (i.e., STA 2) that accepts the reconnection generally sends the response message to the initial link (the connection link before reconnection). However, by using the characteristics of multi-links, the response message can also be sent through any other link (i.e., other STA).

[0431] If STA 2 accepts the link reconnection request, after sending the response message, STA 2 may disconnect its initial connection with AP 2 and may request a link reconnection with AP 3. At this time, the reconnection request process may be executed in the same manner as the existing link establishment process between MLDs. After completing the link establishment process between AP 3 and STA 2, STA2 may perform frame exchange with AP 3 through link 2.

[0432] On the contrary, if STA 2 rejects the link reconnection request, STA 2 and AP 2 may continue to use the link of their initial connection (i.e., link 2) as it is.

[0433] According to an embodiment, when an AP requests a link switch to a STA and when recommending an appropriate link, the STA may or may not switch the link to the recommended link. For example, in order for the AP to be able to recommend a suitable link to the STA, the above-mentioned recommended link may be used.

[0434] For example, as a response message to the AP's request message for requesting reconnection, the STA may accept the link switch. The STA may accept / verify the link switch to the recommended link, and the STA may also request another link switch from the AP based on other information in addition to the information included in the request message.

[0435] Therefore, the AP needs to notify the STA of accepting or not accepting (or rejecting) the response message. For this purpose, the AP may send an acknowledgment message (e.g., a link switch acknowledgment frame) corresponding to the STA's response message (e.g., a link switch response frame) to the STA.

[0436] The detailed operations of the AP MLD and non-AP MLD according to the above embodiments may be referred to Fig. 27 for description.

[0437] Fig. 27 Show the operations of the AP MLD and non-AP MLD for link switching or reconnection.

[0438] Referring to Fig. 27 , AP 2 can request a link switch from STA 2, including recommended link information. In other words, AP 2 can send a link switch request frame including recommended link information to STA 2.

[0439] STA 2 can send an acceptance or rejection of the link request through a link switch response frame.

[0440] For example, when the link switch is accepted, STA 2 can include information about the link to be switched into the link switch response frame and then can send the link switch response frame. At this time, the information about the link to be switched can be the same as or different from the recommended link.

[0441] As another example, when STA 2 selects another link other than the recommended link provided by AP 2 and responds to the request through a link switch response frame, the AP can send a message corresponding to the final acceptance or non-acceptance response to the STA. The corresponding message can be referred to as a link switch confirmation frame.

[0442] For example, AP 2 can accept the link switch to the link specified for STA 2 through a link switch confirmation frame. Based on the link switch confirmation frame, STA 2 can attempt to perform a link switch to the link specified for it.

[0443] As another example, AP 2 can reject the link switch to the link specified for STA 2 through a link switch confirmation frame. STA 2 and AP 2 can maintain their connection to their initial link without any link switch.

[0444] Fig. 27 The illustrated embodiment can also be applied to the case where the AP has sent a link switch request frame without including recommended link information. For example, when an AP (e.g., AP 2) has sent a link switch request frame to a STA (e.g., STA 2) without including any recommended link information, after directly specifying the link to be switched based on information belonging to the STA (or owned by the STA), the STA can respond to the AP through a link switch response frame. In this case, in addition, the AP should send a link switch confirmation frame corresponding to the final acceptance. Therefore, the embodiment in which the AP sends a link switch confirmation frame even when recommended link information is not included in the link switch request frame can be applied.

[0445] Implementation of non-AP MLD request link switching or reconnection

[0446] According to an embodiment, for efficient data transmission, a non-AP MLD may request a link switch or reconnection to an AP MLD. For example, in order to use the STR capability during data transmission, the non-AP MLD may request a switch or reconnection of the connected link to the AP MLD.

[0447] Fig.28 Illustrates the operations of the AP MLD and the non-AP MLD for link switch or reconnection.

[0448] Referring to Fig.28 , the AP MLD and the non-AP MLD may perform link switch negotiation. The STA 2 of the non-AP MLD may send a link switch request frame to the AP 2 of the AP MLD. In response to the link switch request frame, the AP 2 of the AP MLD may send a link switch response frame to the STA 2 of the non-AP MLD. Although the link switch request frame or the link switch response frame may be sent and / or received through the link that is the target of the switch, the present disclosure is not limited thereto. The link switch request frame or the link switch response frame may be sent not only through the link that is the target of the switch but also through various other links.

[0449] The non-AP MLD may request link switch or reconnection through various methods. Hereinafter, three different methods by which the non-AP MLD requests link switch or reconnection may be presented. More specifically, these three different methods may be described in the order of a request method, a non-request method, and a general method.

[0450] 1) Request method : This is a method in which the non-AP MLD requests various information of the APs included in the AP MLD from the AP MLD and accordingly receives the various information. For example, the various information may include information about capabilities, action elements, and BSS parameters.

[0451] According to an embodiment, the method by which the STA requests information of other APs connected to the AP MLD may be used not only for the case of reconfiguring the link but also for various other cases. For example, after multi-link establishment, the STA may request BSS parameter information of other APs for link switch and may select the best link based on the received information. Alternatively, during the discovery process, the STA may request BSS load information of each AP from the AP MLD and may select the link through which to perform link establishment based on the received information. (However, hereinafter, the case where the number of APs of the AP MLD is greater than the number of STAs in the non-AP MLD will be assumed.)

[0452] Therefore, the AP that has received the information request message can send any type of information among the capability information of all APs within the AP MLD, BSS parameter information, key parameters, and / or operation element information. The above examples can be applied to all embodiments described hereinafter.

[0453] 2) Unsolicited Methods : This is a method in which the AP sends various information without any separate information request from the non-AP MLD. The STA can use the received information in various situations. According to an embodiment, the method in which the AP of the AP MLD sends information of other APs without any separate information request from the STA can be used not only for the case of reconfiguring the link, but also for various other cases. Therefore, the AP that has received the information request message can send any type of information among the capability information of all APs within the AP MLD, BSS parameter information, key parameters, and / or operation element information. The above examples can be applied to all embodiments described hereinafter.

[0454] 3) General approach : This is a method in which the non-AP MLD requests link (re)selection based on various information obtained through the previous beacon frame without additional information.

[0455] 1) Request method

[0456] Hereinafter, embodiments related to the above request methods can be described first.

[0457] According to an embodiment, the non-AP MLD can request information for selecting a suitable link from the AP MLD before link switching or reconnection. The STA can use per-AP data payload information or per-link capability information (or information of other links) to select a suitable link.

[0458] For example, the per-link capability information can be included in a beacon frame or the like and sent periodically.

[0459] As another piece of information, as optional information, the per-link capability information may not be included in the beacon frame sent in each cycle period. Alternatively, in order to reduce frame overhead, the STA can receive only the information of the connected link or the associated part of the link. Alternatively, when the beacon reception cycle period is long due to the characteristics of the non-AP MLD (e.g., a low-power device), the non-AP MLD may not be able to receive the per-link capability information for selecting a more suitable link.

[0460] In the above case, the non-AP MLD may request the latest information on the per-link capabilities information and per-link information (e.g., BSS parameter information or operating element information, etc.) of the AP MLD. The links for the per-link capabilities information and per-link information may include not only the links on which transmission and / or reception is in progress, but also other links. For example, fields (A-control field of the 11ax standard) of QoS data frames, management frames, probe response / request frames, PS poll frames, or null frames may be used to request / send the latest information. Alternatively, a separate new frame may be defined to request / send the latest information.

[0461] According to an embodiment, in order to request the latest information on the per-link capabilities information and per-link information of the AP MLD, the STA may send a request message for the information required for requesting link reselection to the AP. For example, the probe request frame defined in the related art may be reused for the request message. As another example, a new frame for the request message may also be defined.

[0462] According to an embodiment, the STA may specify the specific information required and may request the specified information from the AP. The specific information that can be specified may vary according to the situation. That is, the STA may request only the information corresponding to a specific link, or may request only the information corresponding to a specific capability. For example, the information corresponding to a specific link may include information related to the BSS load / parameters of the specific link. In addition, the information corresponding to the capability may include the BSS load information of all links or the BSS load information of a specific link. In this case, the AP may send only the information specified by the STA through the response message. The detailed embodiments related to the request and response of specific information may be described by the embodiments related to the definition and operation of the IOM.

[0463] As another example, the STA may request all the capabilities information currently carried by the AP MLD (e.g., including information on other links) through the request message.

[0464] As shown in the above examples, the embodiments of sending all the information carried by the AP or only sending the specific information specified by the STA may be defined / configured differently. For example, in order to specify (or send) only the specific information, the AP may send all the information or the specified information based on a separate field or bitmap, etc.

[0465] Generally, although the message requesting information from the AP MLD may be sent by the STA that wishes to reconnect, the message may also be sent to any STA (i.e., other STAs) according to the situation (channel situation or link state).

[0466] The AP MLD that has received the request message can send a response message (i.e., an information message) to the non-AP MLD, including information (such as per-link data load information, STR capability information between links, etc.) required for link re-selection. For example, when the probe request frame of the relevant technical specification is reused for the request message, the AP (or AP MLD) should respond to the request message by using the probe response frame as the response message.

[0467] Although the response message can generally also be sent by the AP that has received the request message, it can also be sent to any AP (i.e., other APs) by using the characteristics of multi-links.

[0468] Optionally, the AP MLD can send a "recommended link" element for recommending a suitable link to the STA together with a response message including the above various information (such as the latest information required for link re-selection).

[0469] The above request method can be used by the STA of the non-AP MLD for link switching or reconnection. For example, when the STA of the non-AP MLD wants to re-select a link due to link congestion, the STA of the non-AP MLD can request the per-link BSS load information and BSS parameter information of the AP MLD connected by using the request method. After receiving the request message, the AP can include the indicated link and information in the response message and then send the response message.

[0470] Hereinafter, in order to distinguish from the request message for link switching and the response message for link switching, the above request message and response message can be described as an information request message and an information response message.

[0471] The STA can re-select a suitable link based on the information included in the above information response message and request link switching or reconnection from the AP MLD through a request message for link switching. The request message for link switching can include information about the AP to which the corresponding STA is to reconnect and link information.

[0472] When the AP MLD that has received the request message accepts the request, the AP MLD can send a response message "accepted". And when the AP MLD rejects (or refuses) the request, the AP MLD can send a response message "rejected".

[0473] When the request is accepted, the AP can start to perform link (re-)establishment based on frame exchange through the link with the re-selected AP after the response message is transmitted. On the contrary, when the request is rejected, the STA can continue to use its initially connected link as it is.

[0474] Examples of the detailed operations of the AP MLD and non-AP MLD according to the request method can be referred to Fig.29 Description

[0475] Fig.29 Illustrates the operations of AP MLD and non-AP MLD for link switching or reconnection.

[0476] Referring to Fig.29 , when STA 2 of the non-AP MLD wants to reselect its connected link, STA 2 can send an information request message to the non-AP MLD via Link 2. After receiving the information request message, the AP MLD can send an information response message including the information required for the link re-selection of the non-AP MLD. STA 2 of the non-AP MLD can send a request message for link switching (i.e., link switch request frame) to AP 2 of the AP MLD based on the information included in the above information response message. Thereafter, STA 2 can receive a response message for link switching (i.e., link switch request frame) and can perform link (re)establishment for link switching.

[0477] Embodiments related to the information request proposed in this specification can also be used / applied to the situation where a STA requests necessary (or required) information from an AP. When the information included in a frame (e.g., beacon) received by the STA from the AP is insufficient, the STA can request the insufficient (or missing) information from the AP. For example, when the AP only sends information about the connected link without including information about other links, or when the AP only sends information related to the update or non-update of information about other links, the STA can request the insufficient (or missing) information from the AP.

[0478] A detailed example of the embodiment can be described with reference to Fig.30 to describe.

[0479] Fig.30 Illustrates the operation of requesting information about other APs on the non-AP MLD.

[0480] Referring to Fig.30 , the AP MLD (or APs 1 to 3) can send only information related to the update or non-update of information about other APs (i.e., links) to the STA via a beacon frame. Therefore, STA 2 can send an information request message (or information request frame) to AP 2. STA 2 can receive an information response message (or information message) based on the information request message. STA 2 can receive / obtain information about other APs based on the information response message.

[0481] For example, information about other APs of the AP MLD (e.g., BBS load, etc.) may not be included in the beacon, or AP 2 can only send information related to the update or non-update (e.g., version / updated version) of information about other APs.

[0482] STA 2 may need information of (or information related to) AP 1. STA 2 may request the necessary information through AP 2. STA 2 may obtain the information of AP 1 through the response message to the request. STA 2 may use the information of AP 1 to reselect a suitable link for link switching. For example, frames for link switching may be configured differently.

[0483] In addition, even before multi-link establishment, the STA may use the above request method to obtain the information of the APs carried by the AP MLD. During the multi-link establishment process between the non-AP MLD and the AP MLD, when the number of APs carried by the AP MLD is greater than the number of STAs carried by the non-AP MLD, the STA of the non-AP MLD should determine to which AP of the AP MLD the link should be established. In this case, the STA of the non-AP MLD may request per-link specific information (such as the BSS load information of the APs carried by the AP MLD, etc.) from the AP to know the per-link status. For example, the STA may be a probe request as the request message. As another example, a new frame may be defined for the request message. The STA may include an indicator for requesting a specific element (such as a request element or an extended request element or a PV1 probe response option element, etc.) and an indicator for indicating specific link information (such as a link ID, etc.) in the request message, and then send the request message.

[0484] For example, the STA of the non-AP MLD may send a request message that includes an instruction to request the current BSS load information of all APs within the AP MLD to be connected. The AP that has received the request message may send the required information (the BSS load information of all APs of the AP MLD connected to the corresponding AP) to the STA based on the instruction of the STA by loading the information in the response message. At this time, the STA that has verified the BSS load information of each AP may select the link to be connected according to the order of the BSSs (i.e., APs) with the minimum BSS load. The STA may indicate the link selected during multi-link establishment. In other words, information about the link selected during multi-link establishment may be sent to the AP.

[0485] Such an STA may use the above request method as a method to obtain per-AP information of the AP MLD in order to select the link to be connected before multi-link establishment.

[0486] Although the request method proposed in this specification can be used to obtain the information of other APs after multi-link establishment, this request method can also be used to obtain the information of other APs even before multi-link establishment.

[0487] In the following, new elements / fields including information for a STA to select a suitable link for non-AP MLD can be proposed.

[0488] For example, a "STA ratio per link" (element / field) can be proposed. The "STA ratio per link" can include information related to the ratio of the number of STAs connected per link. For a detailed example of the "STA ratio per link", reference can be made to Fig.31 the description.

[0489] Fig.31 which shows a detailed example of the STA ratio per link.

[0490] Reference is made to Fig.31 , and the STA ratio per link (element / field) can include information related to the number or ratio of STAs connected to each link in the entire AP MLD.

[0491] For example, when a total of 50 STAs are connected to an AP MLD with 3 links, 10 STAs can be connected to link 1 and 20 STAs can be connected to link 2. The AP MLD can send information about the STAs connected per link to the non-AP MLD through the STA ratio per link (element / field) as information related to a value or ratio (%).

[0492] For example, when the information about the STAs connected per link is expressed as a value, link 1 can be expressed / configured as 10, and link 2 can be expressed / configured as 20. Therefore, the value of the STA ratio per link 1 can be configured to be equal to 10. Additionally, the value of the STA ratio per link 2 can be configured to be equal to 20.

[0493] As another example, when the information about the STAs connected per link is expressed as a ratio, link 1 can be expressed / configured as 20 (10 / 50)%, and link 2 can be expressed / configured as 40 (20 / 50)%. Therefore, the value of the STA ratio per link 1 can be configured to be equal to 20. Additionally, the value of the STA ratio per link 2 can be configured to be equal to 40.

[0494] The above examples are only exemplary, and the information about the STAs connected per link can be configured differently. Besides the above examples, the information about the STAs connected per link can be configured to be equal to a relative value.

[0495] The STA can verify / obtain the number and ratio of STAs connected per link based on the above information about the STAs connected per link, which can be used as information for link selection.

[0496] According to an embodiment, in addition to the above "STA ratio per link" (element / field), various information / elements / fields may be included in the information response message. For example, the following information / elements / fields may be included in the information response message.

[0497] - BSS load information per AP

[0498] - STR capability information between links

[0499] - TXOP information per link

[0500] - NAV information per link

[0501] - Recommended link information (i.e., "Recommended Link" element)

[0502] - STA ratio information of the STA connected per link (i.e., "STA ratio per link" element)

[0503] - Others

[0504] In addition to the above information / elements / fields, various information required for link selection may be included in the information response message and then sent.

[0505] The STA that has received the information (e.g., the information described in the above example) selects the AP to which the STA intends to switch or reconnect based on the received information. Then, the STA may send a request message for reconnecting the link. When the AP MLD that has received the request message accepts the request, the AP MLD may send a response message "Accepted". And when the AP MLD rejects (or refuses) the request, the AP MLD may send a response message "Rejected".

[0506] When the request is accepted, the AP may start frame exchange through the link with the reselected AP after the response message is transmitted. On the contrary, when the request is rejected, the STA may continue to use its initially connected link as it is.

[0507] 2) Non-request method

[0508] Different from the request method of directly requesting additional information from a non-AP MLD, according to the non-request method, the AP MLD may send additional information to the non-AP MLD through a beacon frame or a separate frame (e.g., a field of a QoS data frame (A-Control field of the 11ax specification), a management frame, a FILS discovery frame, a non-request probe response frame, a PS poll frame, or an empty frame, etc.) without any additional information request from the non-AP MLD. As another example, a new frame may be defined as the frame for sending additional information to the non-AP MLD.

[0509] For example, when the beacon period is relatively long, the mandatory information required for link switching of a non-AP MLD may be insufficient or may not be the latest information. Therefore, the AP can send a frame including the link capability information of the AP MLD to the non-AP MLD. Thereafter, the non-AP STA can obtain the latest information on the per-link capabilities of the AP MLD. The frame can be sent periodically or can be sent aperiodically.

[0510] For example, when the frame is sent periodically, the AP can send a frame for sharing the latest information of the AP. At this time, the time interval should be shorter than the cycle period of the beacon sent by the AP. Additionally, when the FILS discovers that the frame is used as a frame, a frame can be sent every 20 us. As another example, the cycle period negotiated through the capability negotiation between the AP and the STA can also be used. For example, the transmission period can be indicated by the "periodic" field and the "interval" field / subfield values of the IOM capability element.

[0511] As another example, when the frame is sent aperiodically, the AP can send a frame each time an update event occurs in the information (capability, BSS parameter, operation element) of the AP. As a detailed example, each time the link capability of the AP changes, the changed information can be sent to the connected STA. In this case, the STA can maintain the latest information on the link capability.

[0512] According to the above examples, since the non-AP STA does not send a separate request message for obtaining the link capability, this can have the effect of generating relatively less frame exchange overhead compared to the request method. Additionally, since the STA can receive the updated information each time the main information is updated, this can have the effect of enabling the STA to usefully use the received information.

[0513] Examples of the detailed AP MLD and non-AP MLD operations according to the non-request method can be referred to Fig.32 for description.

[0514] Fig.32 illustrates the operations of the AP MLD and the non-AP MLD for link switching or reconnection.

[0515] Referring to Fig.32 , the AP MLD can send the mandatory information required for link reselection to the non-AP MLD through a separate frame (e.g., an information message) without any separate request message from the non-AP MLD.

[0516] According to an embodiment, compared with Fig.32Differently, the AP MLD can send information about link capabilities to the STA through fields of DL frames (e.g., QoS data frames) that the AP MLD can send to the non-AP MLD without any separate request message from the non-AP MLD. The operations of the AP MLD and the non-AP MLD according to the embodiments can be referred to Fig.33 for description.

[0517] Fig.33 illustrates the operations of the AP MLD and the non-AP MLD for link switching or reconnection.

[0518] Referring to Fig.33 , AP 2 can send information about another AP (or information related to another AP) to STA 2 based on the DL frame (i.e., DL 1). In other words, the DL frame can include information related to another AP. For example, information about another AP can be included in the A-Control field etc. of the 802.11ax specification. According to the embodiment, since the existing DL frame is used without any separate message, this has the effect of reducing frame overhead. If real-time information is required due to a change in the critical information of another AP, the updated information can be sent through a separate message, as shown in the embodiment of Fig.32 .

[0519] For example, the critical information of the AP can include the following A to Q.

[0520] A. Include a channel switch announcement element

[0521] B. Include an extended channel switch announcement element

[0522] C. Modify the EDCA parameter element

[0523] D. Include a silent element

[0524] E. Modify the DSSS parameter set

[0525] F. Modify the CF parameter set element

[0526] G. Modify the HT operation element

[0527] H. Include a wide bandwidth channel switch element

[0528] I. Include a channel switch wrapper element

[0529] J. Include an operation mode notification element

[0530] K. Include a silent channel element

[0531] L. Modify the VHT operation element

[0532] M. Modify the HE operation element

[0533] N. Insert broadcast TWT element

[0534] O. Include BSS color change announcement element

[0535] P. Modify MU EDCA parameter set element

[0536] Q. Modify spatial reuse parameter set element

[0537] Therefore, regardless of the cycle period (or periodicity) of the beacon frame, the non-AP MLD can obtain the latest link capability information. The non-AP MLD can select a suitable link when performing link switching based on the received information. Based on the received information, the STA can reselect a suitable link and can request link switching or reselection from the AP MLD. The request information can include information about the AP and information about the link to which the STA is to reconnect. In addition, when the AP MLD that has received the request message accepts the request, the AP MLD can send a response message "Accepted". And, when the AP MLD rejects (or refuses) the request, the AP MLD can send a response message "Rejected".

[0538] When the request is accepted, the AP can perform link (re)establishment by frame exchange over the link with the reselected AP starting from after the transmission of the response message. Conversely, when the request is rejected, the STA can continue to use its initially connected link as it is.

[0539] 3) General methods

[0540] According to the general method, the non-AP MLD can request link switching or reconnection based on the information currently carried (or owned) by the non-AP MLD without any additional information request. The information used at this time can include information about the AP MLD and information about the non-AP MLD (e.g., information about per-link STR capabilities, information about link status (enabled / disabled), etc.) included in previously received beacons or management frames, etc.

[0541] Different from the non-request method, the STA can send a request message for link switching or reselection to the AP MLD without any separate information request to the AP MLD. The request message can include information about the AP and information about the link to which the STA is to reconnect. When the AP MLD that has received the request message accepts the request, the AP MLD can send a response message "Accepted". And, when the AP MLD rejects (or refuses) the request, the AP MLD can send a response message "Rejected".

[0542] When the request is accepted, the AP can perform link (re)establishment by frame exchange over the link with the reselected AP starting after the response message is transmitted. Conversely, when the request is rejected, the STA can continue to use the link of its initial connection as it is.

[0543] Examples of detailed AP MLD and non-AP MLD operations according to the general method can be referred to Fig.32 for description.

[0544] Fig.34 Show the operations of AP MLD and non-AP MLD for link switching or reconnection.

[0545] Refer to Fig.34 , for the reason of ensuring QoS, STA 2 may want to directly switch its link. If STA 2 has existing information received from the AP MLD (e.g., information received through beacon frames or management frames, etc.), or if STA 2 has determined the link it wishes to reconnect to, then STA 2 can request link switching or reconnection without any separate information request.

[0546] STA 2 can send STA information (e.g., STAID, etc.) and information about the link intended to be switched (e.g., link ID or AP BSS information, etc.) by including the corresponding information in the link switching request frame. When the AP MLD that has received the request frame accepts the request, the AP MLD can send a link switching response frame "Accepted" to STA 3 over the existing link 2. Thereafter, after performing the link (re)establishment process, the non-AP MLD STA 2 can reconnect to AP 3.

[0547] Implementation of anchor link switching and reconnection

[0548] According to an embodiment, the AP MLD can support an anchored link. When the AP MLF supports an anchored link, additional details are considered in the above embodiments of link switching and reconnection.

[0549] The AP MLD can support one anchored link or more than one anchored link, and the AP MLD can provide information about one anchored link or more than one anchored link to the non-AP MLD through the anchored link list information / element. The non-AP MLD can select one link or more than one link from the above-mentioned anchored link list and can use the selected link. The remaining links not selected as anchored links can operate as non-anchored links.

[0550] There is a trade-off between the anchored link and the non-anchored link in terms of power consumption and data load. That is, when the non-AP MLD uses one anchored link, the power consumption can be reduced. However, it may be difficult to ensure the data (more specifically, the data of beacons and management frames) transmission QoS. On the contrary, when multiple anchored links are used, the data transmission QoS can be ensured. However, the amount of power reduction may be decreased.

[0551] Therefore, the non-AP MLD should be able to dynamically request re-selection on the anchored link for efficient data exchange. Therefore, hereinafter, embodiments in which the non-AP MLD dynamically requests anchored link switching / re-selection can be proposed.

[0552] First, the MLD structure supporting the anchored link can be referred to Fig.35 for description.

[0553] Fig.35 An example of the MLD structure supporting the anchored link is shown.

[0554] Referring to Fig.35 , among the 5 links, the AP MLD can use 2 links (i.e., AP 1 and AP 4) as the anchored links. The non-AP MLD can use one anchored link by selecting Link 1 from the two links used as the anchored links. The remaining links of the non-AP MLD can be connected to the non-anchored links (Link 2, Link 3). That is, the non-AP MLD should always monitor the reception of beacons and management frames on Link 1.

[0555] According to the embodiment, for reasons such as load balancing, STA 1 can request the initially used anchored link from the anchored link of AP 1 to the anchored link of AP 4. To switch the anchored link, the above-described embodiments related to link switching can be applied.

[0556] However, among the links supported by the AP MLD, the anchored links are limited to some links. Therefore, the AP MLD can have a separate anchored link list. The non-AP MLD (or STA) should select one link included in the anchored link list and then can request switching or reconnection. In addition, since the non-AP MLD should have at least one or more anchored links, when requesting link switching or reconnection, the non-AP MLD should request anchored link switching while considering this requirement.

[0557] For the above-described embodiments, the AP MLD needs to additionally provide the "anchored link list" information to the non-AP MLD. The above term "anchored link list" is only exemplary, and thus various other terms can be used for configuration / expression.

[0558] - "anchor link list" (element / field): This is information about the list of anchored links supported by the current AP MLD. For example, information about the list of anchored links supported by the current AP MLD can be indicated / configured as one or more link IDs or AP BSS values, etc. The non-AP MLD should connect to at least one or more of the links included in the list.

[0559] The above information (e.g., the "anchored link list" (element / field)) can be included in an existing beacon or management frame and then sent, or in the case of the above request method, the above information can be included in an information response message and can be sent to the non-AP MLD together.

[0560] Therefore, in the case where the non-AP MLD requests to switch the anchored link it is using, the non-AP MLD should be informed in advance about the information of the currently supported anchored link list. However, if the non-AP MLD is not informed (or does not know) the anchored link list information or wishes to obtain the latest information, the non-AP MLD can use the request method to obtain the corresponding information from the AP MLD.

[0561] The STA can only request to switch or reconnect to one link in the anchored link list. If the STA requests to switch or reconnect to another link not included in the list, the AP MLD can send a rejection message to the STA.

[0562] When requesting an anchored link switch or reconnection, there are additional details that should be considered in addition to the existing link switch method. The case where the STA of the non-AP MLD switches its anchored list can be roughly divided into 2 cases.

[0563] The first case corresponds to the situation where the STA that has been connected to an anchored link switches to another anchored link of the AP MLD for reasons such as load balancing (AP switch of the anchored link). The second case corresponds to the situation where the STA that has been connected to an anchored link is disabled for reasons such as power state, and thus another STA of the non-AP MLD reconnects to the anchored link (STA switch of the anchored link).

[0564] The first case can operate similarly / similarly to the above-described implementation of link switch and reconnection. However, when reselecting a link, the STA should only select a link from the list of anchored links supported by the AP MLD. In the case of selecting another link, the AP MLD can send a rejection response message.

[0565] The second case requires additional consideration. An example of the second case can be referred to Fig.34 for description.

[0566] Fig.36An example showing a situation where an anchored link switch or reconnection is required.

[0567] Referring Fig.36 , in the case of a STA that is not an AP MLD, the state of STA 1 may be disabled for various reasons (such as power failure, etc.). At this time, since both STA 2 and STA 3 are currently connected to the non-anchored link, either of the two STAs should reconnect to the anchored link.

[0568] As Fig.36 shown, when the non-AP MLD needs to reconnect to the anchored link, the non-AP MLD can try to reconnect one of STA 2 or STA 3 to the anchored link.

[0569] For example, when the non-AP MLD knows (or has) information about the list of anchored links supported by the AP MLD, the non-AP MLD can select a suitable link and can request a link switch.

[0570] As another example, when the non-AP MLD does not have information about the list of anchored links supported by the AP MLD, the non-AP MLD can obtain the information by making an information request to the AP MLD, and then can select a suitable link and request a link switch.

[0571] Examples of the detailed operations of the AP MLD and non-AP MLD according to the above embodiments can be referred to Fig.37 described.

[0572] Fig.37 Show the operations of the AP MLD and non-AP MLD for anchored link switching or reconnection.

[0573] Referring Fig.37 , in the case where STA 1 connected to the anchored link is disabled, the non-AP MLD needs a new anchored link connection. At this time, the non-AP MLD can disconnect the initial connection of STA 3 to AP 3 via the non-anchored link, and can try to reconnect to the anchored link.

[0574] For example, STA 3 can try to connect to AP 1 that was initially used as the anchored link. As another example, STA 3 can try to establish a connection with a new AP 4 based on various information.

[0575] The process of selecting a new anchored link can be performed similarly / similarly to the above embodiments of link switching and reconnection. For example, STA 3 can request reconnection by selecting the anchored link recommended by the AP or by directly selecting the anchored link by itself. After completing the reconnection of the anchored link, the link of STA 3 can operate as the anchored link.

[0576] Element / field including information related to the anchor link

[0577] According to an embodiment, when information related to an anchored link supported by an AP MLD changes, or when an STA directly requests information about an anchored link, the AP MLD may send corresponding information (i.e., information related to the switched anchored link or information related to the anchored link requested by the STA) to the non-AP MLD.

[0578] For example, this information may be included in a beacon frame as information related to the currently used anchored link and then sent, or this information may be included in a separate management frame and then sent.

[0579] The information about the anchored link may include an "Anchored Link List" element indicating the above-mentioned anchored links supported by the AP MLD and information indicating the use or non-use of each STA's anchored link.

[0580] Hereinafter, a new element including the above-mentioned information about the anchored link may be proposed. The newly proposed element may be configured as described below.

[0581] 1) "Anchor link indication" element (or field) : The "Anchored Link Indication" element may include information related to the use or non-use of the anchored link of each STA connected to the AP MLD. That is, the "Anchored Link Indication" element may be an element / field indicating the use or non-use of each link or each STA's anchored link of the non-AP MLD.

[0582] 2) "STA ratio per anchor link" element (or field) : The "STA Ratio per Anchored Link" element may include information about the ratio or number of STAs connected to each anchored link. However, herein, only STAs using the anchored link as their link may be considered. In other words, even if the AP MLD supports a first link as an anchored link, STAs using the first link as a non-anchored link may not be included in the STAs connected to each anchored link (or STAs connected to each anchored link).

[0583] According to an embodiment, during all processes of the above-mentioned embodiment of anchored link switching or reconnection, when needed, these elements may be included in the frame as additional information.

[0584] A detailed example of the element may be described with reference to Figure 36 to describe.

[0585] Figure 38 and Figure 39 respectively show detailed examples of the elements for anchored link reconnection.

[0586] With reference toFigure 38 and Figure 39 Regarding the information related to the anchor link, it can be sent through the anchor link list element (or field), the anchor link indication element (or field), and / or the STA ratio element per anchor link (or field). In other words, the elements for anchor link reconnection can include the anchor link list element (or field), the anchor link indication element (or field), and / or the STA ratio element per anchor link (or field).

[0587] According to an embodiment, as described above, the anchor link list element can include information about the link list currently supported by the AP MLD. For example, the information about the link list currently supported by the AP MLD can be indicated based on the link ID or the AP BSS information, etc. In other words, the link list currently supported by the AP MLD can be configured based on the link ID or the AP BSS information.

[0588] According to an embodiment, the anchor link indication element can include information related to the use or non - use of the per - STA anchor link of the non - AP MLD. For example, the information related to the use or non - use of the per - STA anchor link of the non - AP MLD can be indicated by a per - link indication bitmap (i.e., Figure 36 ). As another example, the use or non - use of the anchor link for all STAs can be indicated by a single bitmap (i.e., Figure 37 ).

[0589] As an example, when the information related to the use or non - use of the anchor link is indicated by an indication bitmap according to the link ID, the STA can verify the current anchor link based on the anchor link list element value. Thus, the STA can verify the ratio of the STAs connected to each anchor link. At this time, the indication bitmap field for the non - anchor link can be omitted to reduce the overhead.

[0590] In the bitmap, when the value of one of the bits is equal to 1, this bit can indicate that the link currently connected to the STA is an anchor link. When the value of one of the bits is equal to 0, this bit can indicate that the link currently connected to the STA is a non - anchor link. The embodiment of using a bitmap to indicate the connection or non - connection of the per - STA anchor link is only exemplary. And, therefore, the information related to the connection or non - connection of the per - STA anchor link can be sent through various other embodiments.

[0591] According to an embodiment, the ratio of the STAs of all the links supported by the AP MLD can also be sent. According to an embodiment, the STA ratio element per anchor link can include information about the actual usage ratio or the number of STAs of the per - anchor link's actual anchor link. For example, by only indicating the anchor link indication information in the anchor link list element, this has the effect of reducing the overhead.

[0592] Examples of values that configure the per-anchored-link STA ratio element may be described below.

[0593] For example, an AP MLD may include 5 APs (i.e., AP 1 to AP 5), and AP 1 may be connected to a STA via Link 1. AP 2 may be connected to the STA via Link 2. AP 3 may be connected to the STA via Link 3. AP 4 may be connected to the STA via Link 4. And, AP 5 may be connected to the STA via Link 5.

[0594] The AP MLD may support 2 out of 5 links (i.e., Link 1 to Link 5) as anchored links. Link 1 and Link 4 may be supported / used as anchored links.

[0595] A total of 10 STAs may be connected to Link 1 (or AP 1), and 7 STAs may use Link 1 as an anchored link. This may be expressed as a ratio of 70%, and this may be expressed as a value of 7.

[0596] A total of 20 STAs may be connected to Link 4 (or AP 4), and 5 STAs may use Link 4 as an anchored link. This may be expressed as a ratio of 25%, and this may be expressed as a value of 5.

[0597] By sending the per-anchored-link STA ratio element together with the per-link STA ratio element information described above, more accurate information may be sent to the STA. Generally, since an anchored link may have a relatively larger amount of data traffic compared to a non-anchored link, the per-anchored-link STA ratio element may be used as useful information for a STA that intends to reselect its anchored link.

[0598] A non-AP MLD may verify, based on the above information (or elements), whether the link to which the non-AP MLD is connected is an anchored link, the connection rate of STAs per anchored link, and the ratio of the actually used anchored links.

[0599] In addition, when the AP MLD sends information about other links (i.e., all links) via the above elements, the STA may verify, based on one frame, the connection rate and actual usage rate of each STA of all the anchored links of the AP MLD. Therefore, when the STA reselects the anchored link it intends to use, this information (or elements) may be used.

[0600] Therefore, according to the implementation manners of anchor link switching or reselection, by using not only various link information (e.g., information about each AP BSS load or information about each link STR capability, etc.) used in the implementation manners of link switching or reselection, but also the above information about the anchor link (e.g., anchor link list information, information indicating the use or non - use of each STA's anchor link, or information about the actual STA usage rate of each anchor link, etc.), more suitable anchor link switching or re - connection can be performed.

[0601] Signaling indicating link switching and reconnection methods

[0602] To indicate the method proposed above, through the negotiation between the AP MLD and the non - AP MLD, a convention process between the AP MLD and the non - AP MLD may be required. For this purpose, a signaling method for implementing the method to be proposed hereinafter in this specification can be proposed.

[0603] First, to indicate the method proposed above, new elements can be proposed. Hereinafter, although the implementation manners related to the signaling for indicating the link switching and re - connection method will be described, the corresponding implementation manners can also be applied to the implementation manners related to the signaling for indicating the anchor link switching and re - connection method.

[0604] The signaling process for indicating the link switching and re - connection method can be executed during or after the multi - link establishment. In addition, the new elements to be proposed hereinafter can be used in the signaling process for indicating the link switching and re - connection method. For example, these elements can be included in the (re) association frame or a new frame of the relevant technical specification.

[0605] Information Obtaining Method (IOM) capability element

[0606] The IOM capability element can include information related to the enabling or disabling of a method for obtaining additional multi - link information. For example, during the process of exchanging messages for the operation negotiation (or convention) (e.g., capability negotiation process) between the AP MLD and the non - AP MLD during the multi - link establishment process, the IOM capability value can exist in the element of this message. And the existence of the IOM capability value in the element of this message can indicate the support for the IOM capability.

[0607] According to an implementation manner, when the AP MLD supports the IOM capability, the AP can be provided with the internal shared information of other APs and can have (or possess) the information of other APs. An MLD that does not have any shared information of other APs cannot support the IOM capability.

[0608] According to an embodiment, when the value of the IOM capability element is configured to a first value (e.g., 1), this may mean that the IOM capability element enables the IOM and operates the IOM using the indicated capabilities. Conversely, when the value of the IOM capability element is configured to a second value (e.g., 0), this may mean that the IOM capability element disables the IOM.

[0609] According to an embodiment, the IOM capability element may include various fields / elements for indicating various operations. For example, the IOM capability element may further include various fields / elements to be described below. However, depending on the case of an AP MLD request link switch and the case of a non-AP MLD request link switch, the fields / elements added to the IOM capability element may be configured differently. Additionally, among the fields / elements added to the IOM capability element, at least some fields / elements may be omitted. For example, among the fields / elements added to the IOM capability element, fields / elements including information that does not need to be indicated may be omitted.

[0610] Examples of various fields / elements defined / configured to obtain additional information related to multi-links may be described below. The various fields / elements to be described below may be configured independently, or two or more fields / elements may be combined and then sent through various frames. For example, the various fields / elements to be described below may perform operations included and defined in another element. As another example, the various fields / elements to be described below may each be used by being added to another element as an element or an independent field.

[0611] Method type (or method) field / element

[0612] The method type field / element (hereinafter referred to as the method field / element) may include information related to the operation method of the IOM. In other words, the method field / element may indicate the operation method of the IOM. For example, when the non-AP MLD enables (or activates) the IOM method for obtaining information from the AP, the non-AP MLD may select and indicate the method to be used among the above-mentioned methods (e.g., request method, non-request method, general method).

[0613] For example, based on the value of the method field / element being equal to a first value (e.g., 0), the request method may be indicated / used. Based on the value of the method field / element being equal to a second value (e.g., 1), the non-request method may be indicated / used. Based on the value of the method field / element being equal to a third value (e.g., 2), the general method may be indicated / used. And, based on the value of the method field / element being equal to a fourth value (e.g., 3), both the request method and the non-request method may be indicated / used.

[0614] As another example, 1 bit can be used as a method field / element. In this case, based on the value of the method field / element being equal to a first value (e.g., 0), a request method can be indicated / used. Based on the value of the method field / element being equal to a second value (e.g., 1), a non-request method can be indicated / used.

[0615] As another example, 2 bits can be used as a method field / element. In this case, single use or multiple uses of respective methods can be indicated.

[0616] Link range field / element

[0617] When a non-AP MLD requests information from an AP MLD, the range of the requested link can be indicated by a link range field / element. The link range field / element can include information related to whether the STA wishes to request information about all links within the AP MLD or whether the STA wishes to request information about a part of the links within the AP MLD.

[0618] For example, when the value of the link range field / element is equal to a first value (e.g., 0), the link range field / element can mean to request information about all links within the AP MLD. If the value of the link range field / element is equal to a second value (e.g., 1), then the link range field / element can mean to request information about a part of the links within the AP MLD.

[0619] At this time, when the value of the link range field / element is equal to a first value (e.g., 0), since this is a request for all links within the AP MLD, information about a separate link indicator (e.g., a "link condition" field) is not required. On the contrary, when the value of the link range field / element is equal to a second value (e.g., 1), since this is a request for a part of the links within the AP MLD, link indicator information is required.

[0620] According to an embodiment, a field including link indicator information can be included in a multi-link element. An example of a multi-link element can be referred to Figure 40 for description.

[0621] Figure 40 to show an example of a multi-link element.

[0622] Referring to Figure 40 , the multi-link element can be included in various frames. For example, the multi-link element can be included in a probe request frame. According to an embodiment, the multi-link element can include a multi-link control field. For example, the multi-link control field can include a target MLD field. The target MLD field can include link indicator information.

[0623] According to an embodiment, when a non-AP MLD sends a request message for requesting information of an AP ML, a link range field may be added in a multi-link element. An example of the multi-link element may be referred to Figure 41 Description.

[0624] Figure 41 Another example showing the multi-link element.

[0625] Refer to Figure 41 , the multi-link element may further include a link range field. In Figure 41 , although the link range field is configured as a concatenation of multi-link control fields, the present disclosure is not limited thereto. According to an embodiment, the link range field may be included in the multi-link element in various formats.

[0626] As described above, by using the link range field together with the MLD MAC address field, this may indicate whether the field means a request for information of all links within the corresponding MLD or whether the field requests information of partial links. For example, when the value of the link range field is equal to a first value (e.g., 0), this means a request for information of all links. Therefore, since additional link indicator information is not required, the "per STA profile (x)" sub-element may be omitted.

[0627] According to an embodiment, the link range field may also be used by being added to another element without being included in the multi-link element. A corresponding example may be referred to Figure 42 Description.

[0628] Figure 42 An example showing the field configuration proposed in this specification.

[0629] Refer to Figure 42 , an EHT PPDU (or MPDU) may include a link range field, an information range field, a link condition field, and / or an information condition field. As Figure 42 shown, various fields proposed in this specification may be used together in an integrated (or combined) format to indicate the range and conditions of the information requested by the STA from the AP MLD.

[0630] According to an embodiment, when requesting information from the AP MLD, the STA may independently include the proposed respective fields into the request message, and may omit partial fields if not needed.

[0631] Hereinafter, the link condition field, the information condition field, and other various fields / elements shown in the figures may be additionally described.

[0632] Information range field / element

[0633] When non-AP MLD requests information, the information range field can be used to indicate the range of the information.

[0634] For example, when the value of the information range field is equal to a first value (e.g., 0), the information range field can indicate that only a part of the information carried by the AP is provided. Also, when the value of the information range field is equal to a second value (e.g., 1), the information range field can indicate that all of the information (or the whole information) carried by the AP is provided.

[0635] According to an embodiment, although the information range field can be defined to indicate a request for all information (elements) or part of the information (elements) carried by the AP. For example, a subfield for indicating the range of the information to be provided (e.g., all information or part of the information) can be included in the information range field. For example, the subfield for indicating the range of the information to be provided can be defined / configured as an all / part subfield.

[0636] According to an embodiment, a new subfield can be proposed for indicating whether to provide all information or whether to provide only the changed information among all the information. In other words, the newly proposed subfield can indicate whether to provide all information or whether to provide only the changed information among all the information.

[0637] For example, the subfield for indicating whether to provide all information or whether to provide only the changed information among all the information can be defined / configured as an only update subfield.

[0638] When the STA wishes to receive only the changed (or updated) information, the value of the only update subfield can be configured to 1. In other words, when the STA wishes to receive only the changed (or updated) information, the STA can set the value of the only update subfield to 1. For example, when the value of the only update subfield is set to 1, according to the request method, when the STA requests information, the AP (or AP MLD) can send only the changed information (i.e., the updated information) among the requested information. As another example, when the value of the only update subfield is set to 1, according to the non-request method, the AP can notify only the changed information within the information range configured by the STA.

[0639] According to the above example, in order to receive only the changed information, the only update subfield is proposed within the information range field. However, the present disclosure is not limited thereto. And, therefore, in order to receive only the changed information, a separate field or element can be defined / configured.

[0640] According to the above embodiment, the information range that the STA can request can be configured as updated information or all information. In this case, the STA that does not desire a large amount of frame overhead can request to receive only the changed information. Therefore, various overheads can be reduced.

[0641] Link condition field / element

[0642] The link condition field can be used to indicate a specific link being requested. In other words, the link condition field can include information about the specific link being requested. The link condition field can be used when the STA wishes to receive information about only a specific link from the AP.

[0643] The link condition field can be marked (or indicated) by a link identifier (e.g., link ID, BSSID). In other words, the link condition field can include information related to the link identifier (e.g., link ID, BSSID). In other words, to specify the link for obtaining information, the link identifier can be used.

[0644] For example, when a STA connected to Link 1 wishes to request information about only Link 2 and Link 3 from the AP, the STA can indicate Link 2 and Link 3 to the link condition field to request information about Link 2 and Link 3 from the AP. For example, when the above information range field value is equal to 1, all information corresponding to Link 2 and Link 3 can be sent. As another example, when the above information range field value is equal to 0, only the partial information specified by the STA in Link 2 and Link 3 can be sent. According to an embodiment, the partial information specified by the STA can be determined by an information condition field (described below).

[0645] According to an embodiment, when there is no link condition field value, or when the link condition field value is equal to 0, the AP can determine that there is no link condition. Therefore, the AP can provide / send information related to all links to the STA.

[0646] Information condition field / element

[0647] The information condition field can be used to indicate a specific type of information being requested. In other words, the information condition field can be used when the STA wishes to receive only specific information from the AP.

[0648] For example, the information condition field can be used only when the information range field is set to 0. As another example, even when there is no information range field, the information condition field can be used to allow the STA to indicate specific information.

[0649] For example, information that can be specified by the STA (e.g., BSS load, STR capability, etc.) can be indicated by a bitmap within the information condition field. For example, the information type, indication method, or bit order, etc., indicated by the AP can be configured differently.

[0650] According to an embodiment, the information condition field can be used together with the above-described link condition field. According to an embodiment, the information condition field can send request information of various conditions to the STA (or AP) based on a combination of various fields / elements.

[0651] According to an embodiment, in order to allow the STA to request specific information, elements of existing specifications can be reused. For example, in order to allow the STA to request specific information, a request IE or an extended request IE can be used. Details examples of the request IE or the extended request IE will be described below.

[0652] Figure 43 Shows a detailed example of the request element format.

[0653] Refer to Figure 43 , the request element can include an element ID field, a length field, and / or a requested element ID field. For example, the element ID field can include information indicating that the element is a request element. The length field can include information related to the number of octets after the length field. The requested element ID field can include information about the element ID to be requested. The requested element ID field can include a list of the requested element IDs, and the list of element IDs can be listed in ascending order (or increasing order) of the element ID.

[0654] Figure 44 Shows a detailed example of the extended request element format.

[0655] Refer to Figure 44 , the extended request element can include an element ID field, a length field, an element ID extension field, a requested element ID field, and / or a requested element ID extension field. The element ID field and the length field can be configured similarly to the element ID field and the length field of Figure 43 . The element ID extension field can be combined with the element ID field to configure an extended element ID. The requested element ID field can include one of the element IDs for indicating an extended element. The requested element ID extension field can include a 1-octet element ID extension value.

[0656] Refer to Figure 43 and Figure 44 , this element (request element or extended request element) can be used to request specific information of a probe request frame or an information request frame.

[0657] For example, when the STA indicates a list of information it wishes to receive by using the requested element ID, the AP can include the corresponding information in a probe response frame or an information response frame and send it.

[0658] Thus, according to an embodiment of the present specification, the element (request element or extended request element) can be reused as / used as an indicator for requesting specific information. For example, the element can be used together with a link identifier (e.g., Link identifier) to request desired information for a desired link.

[0659] For example, in order to request the BSS load information of AP 2, the STA can use a request element and a link identifier. The STA can include the element ID of the BSS load information through the request element. And the STA can indicate AP 2 through the link identifier. Thus, the STA can request the BSS load information of AP 2 based on the request element and the link identifier.

[0660] According to an embodiment, the above element ID information can be used to indicate specific information of a specific AP through various combinations together with (or with) link identifier information. According to an embodiment, even in the case of defining a new frame for request information instead of an existing frame, the above request element and / or extended request element can be used / reused.

[0661] In the related technical specification, the PV1 probe response option element is used to request specific information. Therefore, in an embodiment of indicating specific information, the PV1 probe response option element can be used.

[0662] Figure 45 A detailed example showing the PV1 probe response option element format is shown.

[0663] Refer to Figure 45 , the PV1 probe response option element can be used to request optional information by using the information desired by the STA as a probe request. For frequently used information, a probe response option bitmap can be used to indicate each information set.

[0664] However, considering MLD, the EHT specification should be able to provide information on multiple links. Therefore, the STA can use a bitmap indicator together with a link identifier to request specific information for various combinations of specific links, as shown in Tables 21 to 26.

[0665] According to an embodiment, in the EHT specification, optional information (e.g., STR capability) can be newly defined together with multiple links. Therefore, when using / reusing the PV1 probe response option element, a bitmap for information that needs to be newly defined or additionally obtained can be newly defined or additionally defined in the EHT specification. The probe response option bitmap can be configured as shown in Tables 21 to 26 below.

[0666] When the i-th bit of the probe response group bitmap is configured to 1, the probe response option bitmap subfield i can be included in the PV1 probe response option element.

[0667] Table 21 shows an example of the probe response option bitmap subfield 0.

[0668] Table 22 shows an example of the probe response option bitmap subfield 1.

[0669] Table 23 shows an example of the probe response option bitmap subfield 2.

[0670] Table 24 shows an example of the probe response option bitmap subfield 3.

[0671] Table 25 shows an example of the probe response option bitmap subfield 4.

[0672] Table 26 shows an example of the probe response option bitmap subfield 5.

[0673] [Table 21]

[0674]

[0675] [Table 22]

[0676] Bit position Subfield Requested item Reference 0 Request RPS RPS element RPS element 1 Request page slice Page slice element Page slice element 2 Request TSF timer accuracy TSF timer accuracy element TSF timer accuracy element 3 Request S1G relay discovery S1G relay discovery element S1G relay discovery element 4 Request S1G sector operation S1G sector operation element S1G sector operation element 5 Request beacon interval Beacon interval element Beacon interval element 6-7 Reserved

[0677] [Table 23]

[0678]

[0679] [Table 24]

[0680] Bit position Subfield Requested item Reference 0 Request measurement pilot transmission Measurement pilot transmission element Measurement pilot transmission element 1 Request multiple BSSIDs Multiple BSSID element Multiple BSSID element 2 Request RM enable capability RM enable capability element RM enable capability element 3 Request AP channel report AP channel report element AP channel report element 4 Request BSS average access delay BSS average access delay element BSS average access delay element 5 Request antenna Antenna element Antenna element 6 Request BSS available admission capacity BSS available admission capacity element BSS available admission capacity element 7 Request BSS AC access delay BSS AC access delay element BSS AC access delay element

[0681] [Table 25]

[0682] Bit position Subfield Requested item Reference 0 Request mobile domain Mobile domain element Mobile domain element 1 Request QoS service capability QoS service capability element QoS service capability element 2 Request channel usage Channel usage element Channel usage element 3 Request time advertisement Time advertisement element Time advertisement element 4 Request time zone Request time zone element Request time zone element 5 Request IBSS parameter set IBSS parameter set element IBSS parameter set element 6-7 Reserved Reserved

[0683] [Table 26]

[0684] Bit position Subfield Requested item Reference 0 Request interoperability Interoperability element Interoperability element 1 Request advertisement protocol Advertisement protocol element Advertisement protocol element 2 Request roaming alliance Roaming alliance element Roaming alliance element 3 Request emergency alert identifier Emergency alert identifier element Emergency alert identifier element 4 Request QLoad report QLoad report element QLoad report element 5 Request multi-band Multi-band element Multi-band element 6 Request multiple MAC sublayers Multiple MAC sublayer element Multiple MAC sublayer element 7 Request reduced neighbor report Reduced neighbor report element Reduced neighbor report element

[0685] According to an embodiment, in order to request specific information about multi-links, the probe response option bitmap subfields 6 or 7 can be newly defined / configured.

[0686] Transmission periodicity field / element

[0687] When the STA wishes to receive information using a non-request method, it can indicate whether the STA receives messages including information periodically or aperiodically by transmitting a periodicity field.

[0688] For example, when the STA wishes to receive information aperiodically, the AP can inform the updated information each time an update occurs in the information of another AP.

[0689] As another example, when the STA indicates that it wants to receive information periodically, messages including the information can be received at the periodic intervals configured for the STA.

[0690] According to an embodiment, the transmission periodicity field can be configured on 1 bit. When the value of the transmission periodicity field is set to 1, the STA can receive / acquire information by the periodic method of receiving messages periodically. When the value of the transmission periodicity field is set to 0, the STA can receive / acquire information by the aperiodic method of receiving messages aperiodically.

[0691] Transmission interval field / element

[0692] According to an embodiment, when the STA wants to receive information of another AP periodically, the STA can directly configure the interval (or transmission cycle period). The STA can send information about the interval for receiving information of another AP based on the transmission interval field. However, herein, this interval should be configured to be shorter than the beacon transmission interval. For example, when using the FILS discovery frame, this interval should be configured to 20 us.

[0693] As described above, the transmission interval can be defined as a separate field within an element indicating the transmission interval, and can also be defined as a sub-field within the transmission periodicity field.

[0694] According to an embodiment, fields / elements defined / configured for obtaining additional information related to multi-link will not be limited to the above fields / elements, and various other fields / elements can also be configured.

[0695] Therefore, during the multi-link establishment process, the MLD (AP MLD or non-AP MLD) can use at least one of the above elements / fields to indicate the IOM capability through negotiation between the AP MLD and the non-AP MLD. Additionally, after the multi-link establishment process is completed, the MDL can update the negotiation details between the MLDs through separate message exchanges.

[0696] According to an embodiment, when the IOM capability is enabled, the AP MLD and the non-AP MLD can operate based on the embodiments of link switching and reconnection.

[0697] In the following, exemplary operations of AP MLD and non-AP MLD when the IOM capability is enabled can be described. For example, by sending the above fields / elements from the non-AP MLD to the AP MLD, the non-AP MLD can request additional information about the multi-link from the AP MLD. The non-AP MLD can send the above fields / elements including the IOM capability element. The fields / elements including the IOM capability element are only exemplary. And, therefore, the IOM capability element can also be sent through a separate field / element.

[0698] For example, during the multi-link establishment process, the non-AP MLD can send an IOM capability element including "Method Field = 0" and "Information Range Field = 1" to the AP MLD, and the non-AP MLD can negotiate with the AP MLD about this. In this case, after the multi-link is established, the non-AP MLD can operate using the request method. Then, when requesting information, the non-AP MLD can request information about the multi-link including all the information included in the beacon (e.g., information about other APs). Therefore, only when the AP MLD has received a request message from the STA, the AP MLD can provide / send information about the link to the response message. When receiving the request message, the AP MLD can send a response message including information about all the links within the AP MLD to the STA. The information about all the links within the AP MLD can include all the information included in the beacon.

[0699] As another example, the non-AP MLD can send an IOM capability element including "Method Field = 1", "Information Range Field = 0", "Link Range = Link ID 2", "Information Condition Field = (value of BSS load indicated by a bitmap)" to the AP MLD, and the non-AP MLD can negotiate with the AP MLD about this. In this case, after the multi-link is established, the non-AP MLD can operate using the non-request method. Therefore, even without a separate request message, the AP can send the BSS load information of Link 2 to the STA through a separate message.

[0700] As another example, the non-AP MLD may send an IOM capability element including "method field = 0", "information range field = 0", "update only field or sub-field = 1", "information condition field = (value of BSS load indicated by bitmap)" to the AP MLD, and the non-AP MLD may negotiate with the AP MLD regarding this. In this case, after multi-link establishment, the non-AP MLD may operate using the request method. Therefore, the AP MLD (or the AP) may include only the updated (or changed) information among the BSS load information of all APs of the AP MLD connected when the STA requests information in the response message, and then may send the message to the STA.

[0701] Hereinafter, in this specification, various examples of new elements that the STA may use to request partial information (i.e., target information) of other APs connected to the AP MLD are provided. The new element may be referred to as an MLD request element. However, the present disclosure is not limited thereto. And, therefore, the new element may also be referred to by various other terms.

[0702] Figure 46 An example of the MLD request element is shown.

[0703] Referring to Figure 46 , the MLD request element 4600 may include an element ID field, a length field, an element ID extension field, a link ID count field, and / or a link ID field.

[0704] For example, when the STA requests information of a specific AP, the link ID count field may include information indicating the number of APs (i.e., links) requested by the STA.

[0705] For example, the link ID field may include indicator information of the AP requested by the STA.

[0706] For example, the STA may send the MLD request element 4600 by including the element in a probe request frame. The AP that has received the probe request frame may send a probe response frame including all the information of the APs indicated in the MLD request element 4600.

[0707] As an example, when the STA wishes to request partial information of the indicated AP rather than all / complete information of the indicated AP, the STA may send a request element or an extended request element defined in the existing standard by including the element together with (or along with) the MLD request element in the probe request frame. After receiving this, the AP may send a probe response frame including only the information indicated in the request element or the extended request element.

[0708] Figure 47 Another example of the MLD request element is shown.

[0709] Refer to Figure 47 , in addition to Figure 46 the MLD request element 4600 shown, the MLD request element 4700 may further include a requested element ID / requested element ID extension field.

[0710] For example, when a STA requests information of a specific AP, the link ID quantity field may include information for indicating the quantity of the APs (i.e., links) requested by the STA.

[0711] For example, the link ID field may include indicator information of the AP requested by the STA.

[0712] For example, when a STA requests specific information (i.e., an element), the requested element ID / requested element ID extension field may be used. The requested element ID / requested element ID extension field may include element ID information of the requested information.

[0713] As an example, when the element ID corresponds to 0 - 254, the requested element ID / requested element ID extension field may include only the element ID information. When the value of the element ID is equal to or greater than 255, the element ID is recognized as an extended element ID, and thus, the requested element ID extension information may be included in the requested element ID / requested element ID extension field together with the element ID information.

[0714] At this time, although the information corresponding to the requested element ID / requested element ID extension field may be defined in the form of a field, the information may also be defined as a new element and may be included in the MLD request element in the form of a sub - element. The new element may be defined / configured as shown in Figure 48 shown.

[0715] Figure 48 Another example showing the MLD request element is presented.

[0716] Refer to Figure 48 , the MLD request element 4800 may include an element ID field, a length field, an element ID extension field, and / or a requested element ID / requested element ID extension field. When the MLD request element 4800 is used, the MLD request element may be indicated as an element without being distinguished as an existing request element or an extended request element. And, thus, this has the effect of reducing the overhead.

[0717] For example, when a STA sends the MLD request element 4800 by including the element in a probe request frame, the AP that has received the request message (i.e., the probe request frame) may send a probe response frame that includes information of the AP indicated in the MLD request element 4800.

[0718] At this time, depending on whether the "requested element ID / requested element ID extension" field is omitted from the MLD request element 4800, the AP can identify the information requested by the STA as either complete information or partial information. The element ID value information defined in this standard is defined in the elements of Section 9.4.2 of the 802.11 standard. In addition, the "requested element ID" and "requested element ID extension" described in this specification can be configured to be the same as in the previous standard. For example, the request element and the extended request element including the "requested element ID" and "requested element ID extension" can be configured / defined as Figures 43 to 44 shown. For example, the request element and the extended request element can be configured as shown in Tables 27 and 28.

[0719] [Table 27]

[0720]

[0721] [Table 28]

[0722]

[0723] According to an embodiment, when the STA requests information from the AP, by including the element in the probe request frame to send the proposed MLD request elements 4700 and 4800, the STA can request information of other APs. The AP that has received this can send only the information requested by the "requested element ID / requested element ID extension" field among the information of the AP requested by the "link ID" field by including the corresponding information in the probe response frame.

[0724] According to an embodiment, when the STA performs transmission after omitting the "requested element ID / requested element ID extension" field, the AP that has received this can send the complete information of the AP requested by the "link ID" field by including the corresponding information in the probe response frame.

[0725] The various formats of the MLD request element proposed above can request the same information for all links. Since the STA can also request other information per link, various options for these requests can be proposed below.

[0726] 1) First, a format for requesting other information per link can be additionally proposed. This can be configured as Figure 49 shown.

[0727] Figure 49 Another example showing the MLD request element is shown.

[0728] Refer to Figure 49, to request other information for each link, the existing request elements and / or extended request element information for each link can be included in the MLE request element 4900. At this time, a new field or element "number of elements" can be defined / configured to notify the length of the requested elements. The "number of elements" information can mean the number of elements requested for the link ID (x). The AP can verify the information requested differently for each link based on the MLE request element 4900, and can send the information requested differently for each link by including the corresponding information in the response frame.

[0729] According to an embodiment, the fields proposed in this specification can be used instead of the request elements and / or extended request elements defined previously in the related art. This can be configured as Figure 50 shown.

[0730] Figure 50 shows another example of the MLD request element.

[0731] Referring to Figure 50 , the MLD request element 5000 can include a "requested element ID / requested element ID extension" field. Each field / element included in the MLD request element 5000 shown in the figure can be omitted as needed.

[0732] 2) Secondly, when the STA requests information, a format for distinguishing common information requested identically for all links from link-specific information requested differently for each link can be proposed. This can be configured as Figure 51 shown.

[0733] Figure 51 shows another example of the MLD request element.

[0734] Referring to Figure 51 , the request elements and / or extended request elements can be included in front of (or before) the link ID number field within the MLD request element 5100. The request elements and / or extended request elements (first elements) can mean the elements of the common information requested jointly for the links indicated later.

[0735] The request elements and / or extended request elements (second elements) listed after the number of elements, together with the link ID (X) placed after the link ID number field, can represent the element information requested for each link. Each field or element can be omitted as needed.

[0736] 3) Thirdly, the fields proposed in this specification can be included in the MLD request element 5200 instead of the existing request elements and / or extended request elements. This can be configured as Figure 52 shown.

[0737] Figure 52Shows another example of an MLD request element.

[0738] Referring to Figure 52 , the MLD request element 5200 may include a "requested element ID / requested element ID extension" field. Each field or element may be omitted as needed.

[0739] For example, the request element or / and the extended request element (the first element) may be represented as an element of the common information requested jointly for the links indicated later.

[0740] The request element or / and the extended request element (the second element) listed after the number of elements, together with the link ID (X) placed after the link ID number field, may represent the element information requested per link.

[0741] 4) Fourth, the common information that is requested identically for all links when the STA requests information may be indicated / sent together with the MLD request element by a separate request element or extended request element. This may be configured as shown in Figure 53 shown.

[0742] Figure 53 Shows an example of an element for requesting common information.

[0743] Referring to Figure 53 , when the STA requests information on multiple links of the AP MLD through a request frame, the information requested jointly may be indicated / sent by an existing request or / and extended request element. Additionally, the information requested differently per link may be indicated / sent by the MLD request element.

[0744] At this time, in some cases, the format of the MLD request element may be defined / configured in various formats. The AP that has received the request message may recognize the information included in the request or / and extended request element as the information requested jointly for the links indicated in the MLD request element. Therefore, the AP may send the corresponding element information for all the links indicated in the MLD request element by including the corresponding information in the response message.

[0745] Additionally, the STA may request other information per link. In this case, based on the information indicated per link within the MLD request element, the AP may send the other information per link by including the corresponding information in the response message.

[0746] Hereinafter, technical features that enable the STA to request partial information of other APs connected to the AP MLD using the multi-link (ML) information element (IE) defined in the EHT standard may be proposed.

[0747] Figure 54 Shows an example of the multi-link element format.

[0748] Referring to Figure 54 , in the EHT standard, a multi-link element (or ML IE) can be defined / configured as shown in Figure 54 to define per-link information. According to an embodiment, various elements or fields can be added to the multi-link element according to the technical features to be presented hereinafter.

[0749] For example, each STA profile (x) sub-element can include various information for the corresponding link. Each STA control field of each STA profile (x) sub-element can include content regarding the corresponding link ID and the information range included in the corresponding sub-element.

[0750] As an example, the information (element) corresponding to the information requested by the STA can be listed in each STA profile (x) sub-element. In other words, the information (element) corresponding to the information requested by the STA can be sent sequentially within each STA profile (x) sub-element.

[0751] As an example, when there is non-inherited information, non-inherited elements can be included in each STA profile (x) sub-element.

[0752] As an example, the complete profile within each STA control sub-element can include information for differentiating (or identifying) the included information as the complete information of the corresponding link or partial information of the corresponding link.

[0753] Therefore, by including the multi-link element (or ML IE) configured / defined as described above in a request frame (e.g., a probe request frame), the STA can use the multi-link element (or ML IE) when requesting partial information from other APs. Various embodiments (or options) for this can be presented hereinafter.

[0754] Hereinafter, in this specification, in order to perform MLD probing using the ML IE, a limiting factor can be defined / configured as described below.

[0755] For example, the STA can use the ML IE from the probe request frame for MLD probing. For example, the element information provided in each STA profile (x) (e.g., element x, element n) can be omitted to reduce overhead. However, different from the probe request frame, when the ML IE is used in an association request / response frame for association, the element information provided in each STA profile (x) should be included.

[0756] For example, when the information requested by the STA is the complete information of the link, a bit indicating the complete information can be configured in each STA control field. In this case, the list of element information sent after each STA control field can be omitted.

[0757] As another example, when the information requested by the STA is partial information of the link, bits indicating the partial information can be configured in each STA control field. In this case, information related to the element ID can be sent after each STA control field.

[0758] The above-mentioned complete information / partial information can be included in the complete profile field. Thus, when the complete profile field is configured with bits indicating complete information, this can mean requesting complete information of the link. When the complete profile field is configured with bits indicating partial information, this can mean requesting partial information of the link.

[0759] Various options related to the case where the STA requests partial information rather than all information (or complete information) of a specific element can be described in detail below.

[0760] According to an embodiment, the information included in the ML IE can vary based on whether the corresponding element is included in an association frame or a probe frame and whether the corresponding frame is a request frame or a response frame.

[0761] For example, when using the ML IE when the STA performs a probe request, although elements including various information within each STA profile (X) can be omitted, otherwise, the element information must be included. Thus, a control field for indicating whether the corresponding element is included in an association frame or a probe frame and whether the corresponding frame is a request frame or a response frame can be proposed below. In other words, the proposed control field can include information related to whether the corresponding element is included in an association frame or a probe frame and whether the corresponding frame is a request frame or a response frame.

[0762] Before describing the proposed control field, an example of the multi-link element and the multi-link control field format can be described first.

[0763] Figure 55 Another example of the multi-link element format is shown.

[0764] Refer to Figure 55 , the multi-link element 5500 can include an element ID field, a length field, an element ID extension field, a multi-link control field, an MLD MAC address field, and / or an optional sub-element field. Various fields / elements can also be included between the MLD MAC address field and the optional sub-element field.

[0765] Figure 56 An example of the multi-link control field format is shown.

[0766] Refer to Figure 56 , the multi-link control field 5600 can include an MLD MAC address presence field. Various fields / elements can also be included in the multi-link element 5500.

[0767] According to an embodiment, various fields / elements can be proposed based on Figure 55 and Figure 56 the multi-link element and the multi-link control field shown. Examples of the proposed fields / elements can be described hereinafter.

[0768] According to an embodiment, a field for indicating the format of a frame including the current multi-link element can be added to the multi-link control field element. This field can be defined as a per-STA element presence field. The name of the field can be configured differently and can also be redefined as needed.

[0769] For example, the per-STA element presence field can indicate whether there is per-STA element list information requested by the current ML IE. In other words, the per-STA element presence field can include information related to whether there is per-STA element list information requested by the current ML IE.

[0770] As an example, when the value of the per-STA element presence field is equal to a first value (e.g., 1), the per-STA element presence field can mean that various element information is included after the per-STA control field within the per-STA profile (x) field.

[0771] As another example, when the value of the per-STA element presence field is equal to a second value (e.g., 0), the per-STA element presence field can mean that various element information is omitted after the per-STA control field within the per-STA profile (x) field.

[0772] The multi-link control field including the per-STA element presence field configured as described above can be configured as Figure 57 shown.

[0773] Figure 57 An example of the multi-link control field format is shown.

[0774] Referring to Figure 57 , the multi-link control field 5700 can include an MLD MAC address presence field, a per-STA element presence field, and / or a reserved field.

[0775] According to an embodiment, as described above, the information included in the ML IE defined in the EHT standard can vary based on whether the corresponding element is included in an association frame or a probe frame and whether the corresponding frame is a request frame or a response frame. Therefore, a field that can indicate this can be proposed. The proposed field can be included within the ML IE of the request / response frame. The proposed field can include information related to the type of frame currently being transmitted by the STA. The content or the arrangement order of the elements additionally configured based on the proposed field (or elements configured by 0 or variables) can vary (or change).

[0776] The proposed field may also be referred to as a frame type field and may be defined / configured as described below.

[0777] Frame type field : This indicator represents the frame type sent by the current STA. The type of the frame including the current ML IE can be indicated based on the value of the frame type field.

[0778] For example, the values of the frame type field can be divided into 0: Association Request, 1: Association Response, 3: Probe Request, and 4: Probe Response, etc. As shown in the above examples, although the frame type can be indicated according to integer values, the frame type can also be indicated by a bitmap.

[0779] As another example, the frame type field can also be used to distinguish MLD Probes proposed in the EHT standard. And, in this case, 5: MLD Probe Request Frame and 6: MLD Probe Response Frame, etc. can be added to the frame type field values.

[0780] As described above, the frame type field can be used to indicate that the element configuration of the ML IE can change based on the frame type. According to an embodiment, each frame type can be arranged in a sub-field format within the frame type field. When the sub-field is set to 1, the frame type field can indicate the frame type corresponding to the sub-field set to 1.

[0781] According to an embodiment, the STA can request partial information about a specific element instead of all information (or complete information). In this case, the Multi-Link Information Element (ML IE) can be configured differently. Hereinafter, when the STA requests partial information about a specific element instead of all information (or complete information), various examples of the ML IE format and various examples of STA and AP operations will be described.

[0782] 1) First, a Request Element and / or an Extended Request Element for indicating the information that the STA wants to request from the corresponding AP can be included in each STA profile (x) of the ML IE.

[0783] The AP that has received the request message indicating the corresponding information can verify the partial information of the link that the STA wants to request through the ML IE information. The AP can send the corresponding information by including the information in a response frame (e.g., a probe response frame). The STA can indicate in the request frame the link ID that it intends to request through each STA profile (x) within the ML IE and whether the currently requested information is complete or partial. Then, the STA can perform the transmission after indicating, through the Request Element or / and the Extended Request Element, the specific information that it wants to request additionally.

[0784] For example, the STA can request specific information that each link wants through the configured multi-link element, as Figure 58 shown.

[0785] Figure 58 Shows another example of the multi-link element format.

[0786] Referring to Figure 58 , the multi-link element 5800 may include a request element or / and an extended request element. However, when requesting all the information of the AP (i.e., complete information), the request element or / and the extended request element may be omitted. Additionally, the element information arranged after each STA control field as described above may be omitted as needed.

[0787] 2) Secondly, the requested element ID / requested element ID extension field for indicating the information that the STA wants to request from the corresponding AP may be included in each STA profile (x) within the existing ML IE. The requested element ID / requested element ID extension field may correspond to the Figures 48 to 53 requested element ID / requested element ID extension field described in

[0788] The AP that has received the request message indicating the corresponding information can verify the partial information of the link that the STA wants to request through the ML IE information. The AP can send the corresponding information by including the information in a response frame (e.g., a probe response frame). The STA can indicate in the request frame the link ID that is intended to be requested through each STA profile (x) within the ML IE and whether the currently requested information is complete or partial. Then, the STA can perform the transmission after indicating the specific information to be additionally requested through the requested element ID / requested element ID extension field.

[0789] For example, the STA can request the specific information that each link wants through the configured multi-link element, as Figure 59 shown.

[0790] Figure 59 Shows another example of the multi-link element format.

[0791] Referring to Figure 59 , the multi-link element 5900 may include the requested element ID / requested element ID extension field. However, when requesting the complete information of the AP (i.e., all element information), the requested element ID / requested element ID extension field may be omitted. Additionally, as described above, the element information arranged after each STA control field may be omitted as needed.

[0792] The format of the multi-link element 5900 can send the element indication information defined in the 802.11 standard as one information set without distinguishing the information into a request element or / and an extended request element. Therefore, this has the effect of reducing the default field overhead (e.g., element ID, length), etc.

[0793] 3) Third, by sending a request element and / or an extended request element for indicating information that the STA is to request from each AP, the STA can request information by distinguishing common information requested commonly for all APs from link-specific information. The ML IE format according to the above-described embodiment can be referred to Figure 60 for description.

[0794] Figure 60 Shows an example of a multi-link element format and additional elements.

[0795] Refer to Figure 60 , when the STA requests information from each AP through a request frame (e.g., a probe request frame), the STA can send the same request for some information, and the STA can request different information per AP for another part of the information. Therefore, the multi-link element 6000 and the request and / or extended request element 6010 can be used / defined to indicate this.

[0796] For example, the request and / or extended request element 6010 (the first element) can be used together with the ML IE within the request frame as an indicator for indicating the same information that the STA requests from the AP to which it sends the request through the request frame. The first element can be sent after the multi-link element 6000 within the request frame.

[0797] As another example, the request and / or extended element 6020 (the second element) within each STA profile (x) can be used as an indicator for indicating other information requested per AP.

[0798] However, as described above, the element information arranged after each STA control field can be omitted as needed.

[0799] For example, the STA can mark (or indicate) information corresponding to the TIM element (e.g., element 5 = 11) in the probe request frame in the request element 6010 (the first element).

[0800] In addition, the STA can mark / indicate in each STA control of each STA profile (x) within the ML IE 6000 that link ID = 1 and full profile = 0. (Conversely, when the value of the full profile is equal to 1, this can mean a request for all element information.) The STA can mark (or indicate) information corresponding to the BSS load element (e.g., element ID = 11) in the request element.

[0801] In addition, the STA can mark / indicate in each STA control of each STA profile (y) within the ML IE 6000 that Link ID = 2 and Complete Profile = 0. The STA can mark (or indicate) information corresponding to non-inherited elements in the extended request element (e.g., Element ID = 255, Element ID Extension = 56).

[0802] When transmitting a frame configured as described above (e.g., a probe request frame), the AP can transmit a probe response frame including the following information.

[0803] - TIM element information for Link 1 and Link 2

[0804] - BSS load element information for Link 1

[0805] - Non-inherited element information for Link 2

[0806] Therefore, according to the above-described embodiments, the STA can distinguish the information requested according to the element hierarchy within the frame into common information or link-specific information, and can request other information per link.

[0807] 4) Fourth, in order to indicate the information that the STA intends to request from each AP, the request element or / and the extended request element can be included in the multi-link element. In this case, the STA can request information by distinguishing common information requested from all APs from link-specific information. The ML IE format according to the above-described embodiments can be referred to Figure 61 for description.

[0808] Figure 61 Another example showing the multi-link element format and additional elements is provided.

[0809] Refer to Figure 61 , when the STA requests information from each AP through a request frame (e.g., a probe request frame), the STA can send the same request for some information, and the STA can request different information per AP for another part of the information. Therefore, the multi-link element 6100 and the request or / and extended request element 6110 can be used / defined to indicate this.

[0810] For example, the request or / and extended request element 6110 can be included in the request frame (e.g., a probe request) together with the multi-link element 6100. The request or / and extended request element 6110 can mean that the STA requests part of the information of the link (i.e., the associated AP) to which the corresponding STA is connected.

[0811] For example, when an STA requests information about an AP that is part of the AP of the AP MLD to which the STA is connected and that is not corresponding to the link of the corresponding STA, the relevant indication information may be included in the multi-link element 6100 (or ML IE 6100). Therefore, when the request or / and extended request element 6120 is included in the ML IE 6100 before the per-STA profile (x) element, the information that the STA jointly requests for other APs (i.e., the APs included in the AP MLD to which the STA is connected and that are not corresponding to the link of the STA) can be indicated by the corresponding element.

[0812] The information jointly requested for other APs can be indicated by the request or / and extended request element 6120 within the ML IE 6100. Additionally, the information differently requested for each other AP can be indicated by adding a request or / and extended request element 6130 after each per-STA control field within each per-STA profile (x).

[0813] At this time, when an indicator of an AP that corresponds to the link of the STA and not to the links of other STAs is included in each per-STA profile (x) within the ML IE 6100, the STA can also obtain information about the AP corresponding to its own link through the ML IE. In this case, in order to request partial information about the AP corresponding to the link of the STA, the request or / and extended request element 6110 included together with the ML IE can be omitted.

[0814] However, as described above, the element information arranged after each per-STA control field can be omitted as needed.

[0815] According to the above-described embodiment, by classifying the information requested according to the element hierarchy within the frame into common information or link-specific information, the STA can request other information per link. To this end, additionally, a new field can be proposed for indicating whether the information requested by the corresponding ML IE differentiates the common information in the multi-link control field.

[0816] As shown in the above-described embodiment, the STA can represent the common information of the corresponding link according to the hierarchy of the request element or / and extended request element. For example, based on the presence of a common information request, it can be determined whether there is a request element or / and extended request element before each per-STA profile (x) within the ML IE in the request frame. Therefore, a control field for indicating this can be proposed hereinafter.

[0817] The proposed field can be defined as a common information presence field. The name of the proposed field can be configured differently and can also be defined with a different name.

[0818] For example, when the value of the field in the common information is indicated as 1, when requesting information about other APs from the AP MLD, the STA can send a request element and / or an extended request element indicating a request for the same information by including the corresponding element before each STA profile (x) element. Also, link-specific information requested differently for each AP can be indicated by a request element and / or an extended request element included in each STA profile (x) element.

[0819] As another example, when the value of the field in the common information is indicated as 0, the common information present field can mean that the STA does not have any information that is equally requested for other APs. Additionally, the common information present field can mean that there is no separate request element and / or extended request element before each STA profile (x) element.

[0820] The multi-link control field according to the above-described embodiment can be configured as Figure 62 shown.

[0821] Figure 62 An example of the multi-link control field format is shown.

[0822] Referring to Figure 62 , the multi-link control field 6200 can include an MLD MAC address present field, a common information present field, and / or a reserved field.

[0823] Implementation of requesting key update information

[0824] According to an embodiment, the STA can make a partial request to the AP of the AP MLD only for critical update information. For this, various embodiments (or options) can be proposed below.

[0825] 1) First, a "critical update request" field can be newly defined / configured to request critical update information of other APs.

[0826] Key update request field : This is a field that requests only the system information defined by the critical update of the AP. For example, the critical update request field can be used together with a link indicator. In this case, this field can be used when requesting the system information defined by the critical update of a specific link.

[0827] When requesting information about other APs of the AP MLD, the STA can set the value of the critical update request field to 1 together with the link indicator information in the request frame (e.g., a probe request frame), and then can send the request frame.

[0828] An AP that has received a request frame can send the received information by including the key update information of the indicated link received in the response frame. The AP can send the change sequence element by including the change sequence element together with the key update information in the response frame.

[0829] At this time, the key update information can include various system information defined by key updates during the 10.46.2 system information update process of the existing 802.11 standard. However, in the case of subsequent 11be, in addition to the system information already defined for key updates in the existing Section 10.46.2, a new information set can be additionally defined. The key update information described in this specification can include the key update information newly defined in the EHT standard.

[0830] For example, when the STA sends a key update request field by setting the value of the corresponding field to 1, the AP can send a response frame according to the existing operation. The key update request field can be included in any element within the request frame and can be used by including it in the above-mentioned MLD request element or ML IE. An example of the ML IE including the key update request field can be referred to Figure 63 Description.

[0831] Figure 63 Another example showing the multi-link element format is shown.

[0832] Refer to Figure 63 , when the STA requests information about a specific link from the ML IE 6300 in a probe request, the STA can request information corresponding to the specific link for each STA profile (x). At this time, the key update request field 6310 can be included in each STA control within each STA profile (x).

[0833] When the key update request field 6310 is set to 1, the AP can send a response frame that includes the current system information defined by key updates in Section 10.46.2 for the link indicated in each STA profile (x).

[0834] Figure 64 Another example showing the multi-link element format is shown.

[0835] Refer to Figure 64 , the key update request field 6410 can be placed (or located) within the ML IE 6400. In this case, the STA can request key update information for all links indicated by each STA profile (x).

[0836] For example, the STA may include the key update request field 6410 in the location within the ML IE 6400 that includes the common information. And after indicating the value of the key update request field 6410 as 1, the STA may send a frame (e.g., a probe request frame). The AP that has received the frame may send a response frame that includes the key update information of the link requested in the received frame (e.g., the probe request frame).

[0837] As another example, the STA may include the key update request field 6410 in a subfield within the multi-link control field within the ML IE 6400, and then may send the key update request field 6410.

[0838] As shown in the above examples, the key update request field format (field or subfield or subelement, etc.) or the location of the key update request field within the ML IE may be defined differently according to the standard.

[0839] Second, a change sequence element can be used to request key update information from other APs.

[0840] In the 11ah standard, the STA may send the change sequence element by including the corresponding element in the probe request frame. The AP that has received the probe request frame may include the change sequence element, which is the key update version information currently carried by the AP, only together with the changed key update information of the corresponding link in the compressed probe response frame, and then send it. Therefore, the change sequence element can also be used in the EHT standard.

[0841] For example, the STA may include the change sequence element together with the link indicator of other APs in the probe request frame, and then send it. The AP that has received the probe request frame may include only the changed key update information of the indicated link in the probe response, and then send it. Thereafter, the AP may include the changed key update information together with the change sequence element in the corresponding response frame, and then send it.

[0842] For example, the change sequence element may be included in any element or subelement within the request frame, and the change sequence element can also be used by including it in the above-mentioned MLD request element or ML IE.

[0843] An example of the multi-link element including the above change sequence element can be referred to Figure 65 description.

[0844] Figure 65 Another example showing the multi-link element format is shown.

[0845] Refer to Figure 65, changing sequence element 6510 may be included within the ML IE 6500. The STA may send a frame (e.g., a probe request frame) including the ML IE 6500. The AP that has received the frame may compare the change sequence field value currently carried by the corresponding AP for the link indicated by the ML IE with the change sequence field value within the change sequence element 6510 sent by the STA. For example, when there is a change in the AP, the AP may include the key update information of the change in the probe response frame and then send it.

[0846] At this time, the change sequence element 6510 sent by the STA must include the change sequence information of all the links of the request information in the ML IE. Therefore, when using the existing change sequence element, the link indicator information that may need to be additionally requested may be required.

[0847] In addition, a new element based on MLD may be proposed hereinafter in this specification.

[0848] MLD change sequence element : This is an element that may include the change sequence information of multiple links.

[0849] An example of the MLD change sequence element may be configured as shown in Figure 66 and Figure 67 shown.

[0850] Figure 66 and Figure 67 show an example of the MLD change sequence element format.

[0851] Referring to Figure 66 , the MLD change sequence element may be configured by arranging the change sequence values repeatedly for each link.

[0852] Referring to Figure 67 , after indicating the number of links as "the number of link IDs", the MLD change sequence element may be configured by indicating each of the link ID information and the change sequence information.

[0853] Hereinafter, an exemplary embodiment of using the MLD change sequence element may be described. First, the MLD change sequence element may be included in the multi-link element. The multi-link element may be configured as shown in Figure 68 shown.

[0854] Figure 68 shows another example of the multi-link element format.

[0855] Referring to Figure 68 , the MLD change sequence element 6810 may be included in the ML IE 6800. When the STA sends a probe request frame including the ML IE 6800, the AP may compare each received change sequence value for each link with each change sequence value carried by the AP.

[0856] The AP can send critical update information for a link change corresponding to an updated change sequence value by including the corresponding information in a response frame. According to an embodiment, when the STA has no other information to send per link, the STA can omit the per STA profile (x) sub-element.

[0857] According to an embodiment, a change sequence element defined in a related technical standard can be used. The change sequence element defined in the related technical standard can be configured as Figure 69 shown.

[0858] Figure 69 An example showing the format of the change sequence element is shown.

[0859] Referring to Figure 69 , the change sequence element 6900 can include an element ID field, a length field, and / or a change sequence field.

[0860] According to an embodiment, an existing change sequence element can be directly used as is within the ML IE without modification. The STA can also request critical update information for per-link updates through the change sequence element.

[0861] Figure 70 Another example showing the format of the multi-link element is shown.

[0862] Referring to Figure 70 , the probe request frame can include the ML IE 7000. The change sequence element 7010 can be included within the per STA profile (x) of the ML IE 7000. The change sequence element 7010 can indicate critical update information for a change in the link indicated by the per STA profile (x) request.

[0863] Therefore, the AP that has verified the change sequence element included in the probe request frame compares the received change sequence value with the change sequence value carried by the AP. Thereafter, when there is an update (i.e., when there is information about a change that the STA should update), the AP can send a response frame including the changed critical update information.

[0864] Third, in order to request critical update information from other APs, the change sequence field can be used together with the "critical update request" field defined above. As an indicator that has been used to allow the STA to request information from another AP, the "critical update request" field has been defined / configured as above. The previously defined / configured "critical update request" field is described below.

[0865] Key update request field:This is a field for system information that requests only critical updates via the AP. For example, the critical update request field can be used together with a link indicator. In this case, this field can be used when requesting system information defined by critical updates via a specific link.

[0866] According to an embodiment, the critical update request field can be configured with 1 bit. The STA can use a 1-bit indicator to request critical updates for a specific link. When the receiving AP does not know the version of the critical update information carried by the current STA (i.e., the change sequence field value of the critical update information carried by the STA), the AP must send a response message including all the critical update information for the requested link. The AP can include the critical update information together with the change sequence element in the corresponding response frame and then send it.

[0867] Although the above embodiment is a simple method, since this method may include overlapping transmissions of information already carried by the STA, technical features for reducing the associated overhead may be required. Therefore, a multi-link element format for these technical features can be additionally proposed. An example of the multi-link element format can be referred to Figure 71 for description.

[0868] Figure 71 Another example showing the multi-link element format is presented.

[0869] Referring to Figure 71 , the STA can include the critical update request field 7120, which is an indicator for indicating a critical update information request, together with the change sequence field 7110 (or change sequence element, change sequence field) indicating the version information of the critical update currently carried by the STA in the request frame and then send it.

[0870] At this time, the change sequence field 7110 can include information related to the indicator. In the EHT standard, the STA can receive the change sequence value of the AP of the AP MLD connected periodically via a beacon or a probe response. Additionally, the STA can store the received change sequence value. Therefore, the STA knows the per-link change sequence value currently received by the STA.

[0871] Therefore, the change sequence field 7110 defined in this specification can include information about the version (i.e., the change sequence value) of the critical update information of the AP of the connected AP MLD that the STA previously obtained via a beacon or a probe response.

[0872] For example, when the value of the critical update request field 7120 is equal to 1, the critical update request field 7120 can mean that the STA requests critical update information. And when the value of the critical update request field 7120 is equal to 0, the critical update request field 7120 can mean that the STA does not request critical update information.

[0873] When the value of the key update request field 7120 is equal to 1, since the key update request field 7120 means a key update information request, changing the sequence field 7110 (or changing the sequence element) can be included in the multi-link element 7100.

[0874] When the value of the key update request field 7120 is equal to 0, the change sequence field 7110 (or change sequence element) can be omitted.

[0875] That is, when the value of the key update request field is equal to 1, by having the STA send the change sequence field (or change sequence element) together, the AP that has received this can compare the received information with the current information carried by the AP itself, and can include only the changed information (i.e., the changed information that only the STA needs to update) in the response frame and then send it.

[0876] Also, when the value of the key update request field is equal to 0, in order to reduce overhead, the STA can omit the change sequence field (or change sequence element) and then can send a frame (e.g., a probe request frame).

[0877] As described above, based on the value of the key update request field, it is possible to distinguish and then define whether there is a change sequence field (or change sequence element).

[0878] Different from the above example, according to the option, the values of the key update request field and the change sequence field (or change sequence element) can be defined and used independently.

[0879] According to an embodiment, the key update request field with a value of 1 can be included in the request message sent by the STA, or there may be a case where the change sequence field (or change sequence element) is not included. The AP that has received this can consider that the STA wishes to receive all key update information, not just the updated key update information. Therefore, the AP can include all key update information in the response message and then send it.

[0880] Hereinafter, in this specification, a method in which the STA sends the key update request field together with the previously obtained change sequence value information can be proposed, and a method in which the AP compares the received change sequence value information with the change sequence value information carried by the corresponding AP and includes only the changed information in the response frame and then sends it can be proposed.

[0881] In the embodiments described below, although the change sequence field (or change sequence field field) is used to convey the change sequence information of the transmission link, the present disclosure is not limited thereto. For example, the STA can also request the changed information by changing the sequence element instead of the change sequence field. Since the embodiments using the change sequence element have been described in detail above, the embodiments using the key update request field together with the change sequence element are omitted in the following description.

[0882] For example, when the STA includes the ML IE in the probe request frame and sends it for MLD probing, the information for requesting the key update can be included in the per-STA profile (x) sub-element for requesting per-STA information.

[0883] As an example, the key update request field is included in the per-STA control field, and the change sequence field field including the key update information of the current STA can be placed (or located) within the per-STA profile (x).

[0884] For example, the key update request field can be placed (or located) within the per-STA profile (x) together with the change sequence field, rather than the per-STA control field.

[0885] An example of the multi-link element including the above key update request field and change sequence field can be referred to Figure 72 description.

[0886] Figure 72 shows another example of the multi-link element format.

[0887] Refer to Figure 72 In, the key update request field 7210 and the change sequence field 7220 can be included in the per-STA profile (x) of the multi-link element 7200. Although the key update request field 7210 and the change sequence field 7220 can also be included in the per-STA profile (y), the information included therein can be configured differently.

[0888] For example, the multi-link element 7200 can be included in the probe request frame and then sent. After receiving the probe request frame, the AP can verify the ML IE 7200 within the probe request frame. The AP can send a response message including the key update information of the specific link requested by the STA.

[0889] As an example, when the key update request field 7210 is within each STA profile (x) element in the ML IE 7200 and its value is equal to 1, the AP can recognize that the STA has requested key update information. Additionally, the AP can compare the change sequence information carried by the STA with the current change sequence information of the link (X) requested by the STA through the received change sequence field 7220 information. When there are update details (i.e., when there is information about changes that the STA should update), the AP can send a compressed probe response frame that includes only the updated information.

[0890] According to an embodiment, the above information (e.g., the key update request field 7210 and the change sequence field 7220) can be included in the ML IE at a common information level rather than a link-specific level, and the key update information can also be requested together for all links rather than a specific link. An exemplary multi-link element related to this can be referred to Figure 73 for description.

[0891] Figure 73 Another example showing the multi-link element format is presented.

[0892] Referring to Figure 73 , the key update request field 7310 (i.e., the value is set to 1) and the change sequence field 7320 can be included in a common information location within the ML IE 7300, rather than a link-specific information location (e.g., per STA profile (x)).

[0893] The STA can send a probe request frame including the ML IE 7300. After receiving this, the AP recognizes that the STA has requested all the links carried by the STA itself, rather than a specific link. Then, the AP can compare the change sequence field information sent by the STA with the current change sequence information of all the links carried by the STA itself. When there are update details (i.e., when there is information about changes that the STA should update), the AP can send a compressed probe response frame that includes only the updated information for all links.

[0894] Figure 74 Another example showing the multi-link element format is presented.

[0895] Referring to Figure 74 , the ML IE 7400 can include a key update request field 7410 and a change sequence field 7420. Different from the ML IE 7300 shown in Figure 73 , the key update request field 7410 can be included within the multi-link control field. The STA can request key update information for changes to the links through the ML IE 7400.

[0896] According to an embodiment, during or after multi-link establishment, the AP MLD and the non-AP MLD may enable the IOM method proposed by the signaling method presented in this specification. Additionally, the AP MLD and the non-AP MLD may limit (or constrain) the scope and type of the requested information through various field values within the IOM capability element.

[0897] According to an embodiment, although the IOM operation may be performed after an accurate operation negotiation is established between the MLDs through the above IOM signaling method, the IOM operation may also be performed through the MLD implementation manner without any separate signaling process. This may mean that the IOM may operate through the AP MLD implementation manner or the non-AP MLD implementation manner without any negotiation between the AP MLD and the non-AP MLD.

[0898] Based on the above embodiments, although the AP MLD and the non-AP MLD may operate, the following limitations may occur when the MLD performs the IOM operation without any separate signaling exchange.

[0899] 1) Limitation on the request method: When information sharing between APs that do not support the AP MLD is not supported, and when the STA has requested information about another link, a response cannot be made (or sent).

[0900] 2) Limitation on the non-request method: The AP may autonomously determine the STA that requires additional link information and may provide a separate message (e.g., beacon interval, etc.) to the corresponding STA. Therefore, the STA cannot predict whether it will receive the information.

[0901] When the MLD implements the IOM without any separate signaling method, the operation process may be simplified. However, the above limitations may occur.

[0902] According to an embodiment, the method for requesting information related to the multi-link may be configured based on the negotiation between the AP MLD and the non-AP MLD performed using the above IOM capability element. On the other hand, in the case of the request method, the STA may indicate specific information other than the negotiated information and may temporarily wish to obtain the corresponding information. In this case, when the STA dynamically sends a request message, the request may be made while including the indication (e.g., IOM capability information).

[0903] For example, during or after multi - link establishment, although the ST can receive information of the AP based on the negotiation details between the AP MLD and the non - AP MLD, the STA may temporarily wish to request information of a specific AP or information of specific parameters of the AP. In this case, when requesting information, the STA can include an instruction regarding the information that the STA wishes to request in the "IOM capability" element within a request frame (e.g., a probe request frame or a (re) association frame or a new frame, etc.), and can send the request frame. The AP can send / provide a response message including the information that the STA wishes to request to the STA based on the request frame. According to an embodiment, when a field within the IOM capability element is omitted, the AP can provide information to the STA based on the previously (or existing) negotiated details.

[0904] Therefore, during the multi - link setup establishment or after the multi - link establishment process, the MLD (AP MLD or non - AP MLD) can use the above - mentioned elements to perform negotiation between the AP MLD and the non - AP MLD. The non - AP MLD can perform negotiation on the information to be provided (or the information to be received) based on the negotiation, and then can receive the corresponding information. Additionally, by including an instruction that the STA wishes to receive the requested information in the request message and sending the request message, the STA can temporarily receive only the requested information. However, herein, when a specific instruction is omitted from the request message, the non - AP MLD and the AP MLD can operate based on the previously (or existing) negotiated instructions.

[0905] According to an embodiment, when the non - AP MLD and the AP MLD wish to change the negotiated details after the multi - link establishment is completed, the non - AP MLD and the AP MLD can update the negotiation details between the MLDs through a separate message exchange.

[0906] Figure 75 is a flowchart describing the operation of a multi - link device.

[0907] Referring to Figure 75 , in step S7510, a multi - link device (MLD) can send a request frame that includes an information field for requesting at least one element related to a second link.

[0908] According to an embodiment, a multi - link device (MLD) can send a request frame including an information field for requesting at least one element related to a second link to a first AP of an access point (AP) multi - link device through a first station (STA).

[0909] For example, a multi-link device can be connected to an AP multi-link device via a plurality of links including a first link. The multi-link device can include a plurality of STAs related to the plurality of links. For example, among the plurality of STAs, a first STA can be connected to the first link. In other words, the first STA can operate in the first link. Additionally, the first STA can be connected to a first AP of the AP multi-link device via the first link.

[0910] For example, the plurality of links and a second link can be in the 2.4 GHz, 5 GHz, and 6 GHz frequency bands.

[0911] For example, a request frame can include a probe request frame. As an example, an information field for requesting information on at least one element related to the second link can be included in the multi-link element included in the probe request frame.

[0912] According to an embodiment, the request frame can include identifier (ID) information about the second link. The identifier information about the second link can be configured by 4-bit information. For example, the identifier of the first link and the identifier of the second link can be expressed in 4 bits.

[0913] According to an embodiment, a set of elements that can be requested via a request frame can be referred to as an element set. Therefore, all / complete elements included in the element set can mean all / complete elements that can be requested via a request frame. The element set can be configured differently based on the frame type. For example, the element set can be configured differently in a probe request frame and an association request frame, respectively.

[0914] For example, at least one element can be included in the element set designated for the second link. In other words, the multi-link device can request partial elements from among the elements (or partial elements) included in the element set designated for the second link.

[0915] As an example, the request frame can include 1-bit information regarding whether at least one element is a partial set or a complete set of elements included in the designated element set.

[0916] Based on the 1-bit information being set to a first value, the multi-link device can request at least one element as partial elements included in the designated element set. Based on the 1-bit information being set to a second value, the multi-link device can request at least one element as all elements included in the designated element set.

[0917] In other words, by configuring the 1-bit information to have a first value (e.g., 0), the multi-link device can indicate a request for partial elements included in the designated element set. Therefore, the 1-bit information included in the request frame can be set to the first value.

[0918] In addition, by configuring 1-bit information as a second value (e.g., 1), the multi-link device can indicate all elements included in a specified set of requested elements.

[0919] According to an embodiment, the information field may include information for identifying at least one element. For example, the information for identifying at least one element may include an identifier (ID) related to the at least one element. In other words, the multi-link device may send the ID of at least one element that the multi-link device itself desires to receive to the AP multi-link device.

[0920] For example, the information for identifying at least one element may be configured by a request element, an extended request element, or a request and / or extended request element. As an example, the information for identifying at least one element may be included in a multi-link element.

[0921] According to an embodiment, the information field may include a first field and a second field. For example, the first field may include information for identifying elements requested for all links operating in the AP multi-link device. The second field may include information for identifying elements only for the second link request.

[0922] In other words, the first field may include information (or ID) related to elements commonly requested by the multi-link device for all links. The second field may include information (or ID) related to elements requested by the multi-link device only for the second link.

[0923] In step S7520, the multi-link device may receive a response frame based on the request frame. According to an embodiment, the multi-link device may receive the response frame from the first AP through the first STA based on the request frame. According to an embodiment, the response frame may include at least one element.

[0924] According to an embodiment, the second link may be distinguished from multiple links. When the second link is distinguished from multiple links, the multi-link device may send a request frame for requesting at least one element related to a link (i.e., the second link) that is not currently connected to the multi-link device itself. The multi-link device may receive at least one element related to a link (i.e., the second link) that is not currently connected to the multi-link device itself through the response frame based on the request frame. The at least one element may include information required for link switching. For example, the at least one element may include only information mandatory for link switching.

[0925] According to an embodiment, the multi-link device may send a second request frame for requesting the link connected to the first STA to switch from the first link to the second link based on the response message. Thereafter, the multi-link device may perform a process of switching the link to be connected to the first STA from the first link to the second link based on the second request frame.

[0926] A multi-link device can establish a connection between a first STA of an AP multi-link device and a second AP based on a process for switching a link connected to the first STA from a first link to a second link. For example, the second AP can operate in the second link. Additionally, the first STA can also operate in the second link. In other words, the first STA can establish a connection with the second AP through the second link based on the above process.

[0927] According to an embodiment, the second link can be included among multiple links. When the second link is included among multiple links, the multi-link device can send a request frame for requesting an element related to a link (i.e., the second link) currently connected to the multi-link device itself through the first link. In other words, the multi-link device can send a request frame for requesting at least one element related to another link (i.e., the second link). The multi-link device can receive at least one element related to a link (i.e., the second link) other than the first link among the links currently connected to the multi-link device based on the request frame through a response frame.

[0928] Figure 76 is a flowchart describing the operation of an AP multi-link device.

[0929] Refer to Figure 76 In step S7610, an AP multi-link device (MLD) can receive a request frame including an information field for requesting at least one element related to the second link. According to an embodiment, the AP multi-link device (MLD) can receive a request frame including an information field for requesting at least one element related to the second link from a first STA of the multi-link device through a first AP.

[0930] According to an embodiment, the AP multi-link device can be connected to the multi-link device through multiple links. For example, the second link can be included among multiple links. As another example, the second link can be distinguished from multiple links.

[0931] For example, the AP multi-link device can be connected to the multi-link device through multiple links including a first link. The AP multi-link device can include multiple APs related to multiple links. For example, among the multiple APs, the first AP can be connected to the first link. In other words, the first AP can operate in the first link. Additionally, the first AP can be connected to the first STA of the multi-link device through the first link.

[0932] For example, the multiple links and the second link can be included within the 2.4 GHz, 5 GHz, and 6 GHz frequency bands.

[0933] For example, the request frame may include a probe request frame. As an example, an information field for requesting information about at least one element related to a second link may be included in the multi-link element included in the probe request frame.

[0934] According to an embodiment, the request frame may include identifier (ID) information about the second link. The identifier information about the second link may be configured by 4-bit information. For example, the identifier of the first link and the identifier of the second link may be expressed in 4 bits.

[0935] According to an embodiment, a set of elements that can be requested through a request frame may be referred to as an element set. Therefore, all elements included in the element set may mean all elements that can be requested through the request frame. The element set may be configured differently based on the frame type. For example, the element set may be configured differently in a probe request frame and an association request frame, respectively.

[0936] For example, at least one element may be included in the element set designated for the second link. In other words, the AP multi-link device may receive a request frame for requesting some of the elements (or partial elements) included in the element set designated for the second link.

[0937] As an example, the request frame may include 1-bit information related to whether at least one element is a partial set or a complete set of elements included in the designated element set.

[0938] Based on the 1-bit information being set to a first value, the AP multi-link device may verify that the request frame is a frame for requesting at least one element that is a partial element included in the designated element set. Therefore, the 1-bit information included in the request frame may be set to the first value.

[0939] Based on the 1-bit information being set to a second value, the AP multi-link device may verify that the request frame is a frame for requesting all elements included in the designated element set.

[0940] According to an embodiment, the information field may include information for identifying at least one element. For example, the information for identifying at least one element may include an identifier (ID) related to at least one element. In other words, the AP multi-link device may verify the ID of at least one element that the multi-link device itself wishes to receive.

[0941] For example, the information for identifying at least one element may be configured by a request element, an extended request element, or a request or / and extended request element. As an example, the information for identifying at least one element may be included in the multi-link element.

[0942] According to an embodiment, the information field may include a first field and a second field. For example, the first field may include information for identifying elements for all link requests operating in the AP multi-link device. The second field may include information for identifying elements only for the second link request.

[0943] In other words, the first field may include information (or ID) related to elements commonly requested by the multi-link device for all links. The second field may include information (or ID) related to elements requested by the multi-link device only for the second link.

[0944] In step S7620, the AP multi-link device may send a response frame based on the request frame. According to an embodiment, the AP multi-link device may send a response frame to the first STA through the first AP based on the request frame. According to an embodiment, the response frame may include at least one element.

[0945] According to an embodiment, the second link may be distinguished from multiple links. When the second link is distinguished from multiple links, the AP multi-link device may receive a request frame for requesting at least one element related to a link (i.e., the second link) that is not currently connected to the AP multi-link device itself. The AP multi-link device may send at least one element related to a link (i.e., the second link) that is not currently connected to the AP multi-link device itself through the response frame based on the request frame. The at least one element may include information required for link switching. For example, the at least one element may include only information mandatory for link switching.

[0946] According to an embodiment, the AP multi-link device may receive a second request frame for requesting to switch the link connected to the first STA from the first link to the second link based on the response message. Thereafter, the AP multi-link device may perform a process of switching the link to be connected to the first STA from the first link to the second link based on the second request frame.

[0947] The second AP of the AP multi-link device may establish a connection with the first STA based on the process of switching the link to be connected to the first STA from the first link to the second link. For example, the second AP may operate in the second link. In addition, the first STA may also operate in the second link. In other words, based on the above process, the first STA may establish a connection with the first STA through the second link.

[0948] According to an embodiment, the second link may be included in a plurality of links. When the second link is included in the plurality of links, the AP multi-link device may receive a request frame for requesting at least one element related to the remaining links (i.e., the second link) other than the first link through the first link. The AP multi-link device may send at least one element related to another link (i.e., the second link) through the first link. The AP multi-link device may receive, based on the request frame, at least one element related to the link other than the first link (i.e., the second link) among the links currently connected to the AP multi-link device through a response frame.

[0949] The above technical features of this specification can be applied to various devices and methods. For example, it can be achieved by Figure 1 and / or Figure 19 executing / supporting the above technical features of this specification. For example, the above technical features of this specification can be only applied to Figure 1 and / or Figure 19 a part of. For example, the above technical features of this specification can be implemented based on Figure 1 the processing chips (114, 124), or based on the processors (111, 121) and memories (112, 122), or based on Figure 19 the processor (610) and memory (620) of. For example, the device of this specification may include a processor and a memory operatively connected to the processor, wherein the processor may be configured to: send, through a first station (STA) included in a multi-link device, a request frame including an information field for requesting at least one element related to a second link to a first AP of an access point (AP) multi-link device, wherein the first STA operates in a first link, and wherein the information field includes information for identifying at least one element; and receive, based on the request frame, a response frame from the first AP through the first STA, wherein the response frame includes at least one element.

[0950] The technical features of this specification can be implemented based on a computer-readable medium (CRM). For example, the CRM proposed in this specification may be encoded as at least one computer program including instructions. When executed by at least one processor, the instructions may perform operations including the following steps: sending, through a first station (STA) operating in a first link, a request frame including an information field for requesting at least one element related to a second link to a first AP of an access point (AP) multi-link device through a first station (STA) included in a multi-link device, wherein the information field includes information for identifying at least one element; and receiving, based on the request frame, a response frame from the first AP through the first STA, wherein the response frame includes at least one element. The instructions stored in the CRM of this specification can be executed by at least one processor. At least one processor related to the CRM of this specification may beFigure 1 a processor (111, 121) or a processing chip (114, 124), or Figure 19 a processor (610). In addition, the CRM in this specification can be Figure 1 a memory (112, 122), or Figure 19 a memory (620), or a separate external memory / storage medium / disk, etc.

[0951] The above technical features of this specification are applicable to various applications or business models. For example, the above technical features can be applied to the wireless communication of devices supporting artificial intelligence (AI).

[0952] Artificial intelligence refers to the research field of artificial intelligence or methods for creating artificial intelligence, and machine learning refers to the research field of methods for defining and solving various problems in the field of artificial intelligence. Machine learning is also defined as an algorithm for improving operational performance through stable experiences of operations.

[0953] An artificial neural network (ANN) is a model used in machine learning and can refer to an overall problem-solving model including artificial neurons (nodes) that form a network by combining synapses. An artificial neural network can be defined by the connection pattern between neurons in different layers, the learning process for updating model parameters, and the activation function for generating output values.

[0954] An artificial neural network can include an input layer, an output layer, and optionally one or more hidden layers. Each layer includes one or more neurons, and an artificial neural network can include synapses connecting the neurons. In an artificial neural network, each neuron can output the function value of the activation function of the input signal, weight, and bias input through the synapse.

[0955] Model parameters refer to parameters determined through learning and include the weights of synapse connections and the biases of neurons. Hyperparameters refer to parameters set before learning in machine learning algorithms and include the learning rate, the number of iterations, the mini-batch size, and the initialization function.

[0956] Learning an artificial neural network can aim to determine model parameters for minimizing a loss function. The loss function can be used as an index for determining optimized model parameters during the process of learning an artificial neural network.

[0957] Machine learning can be classified into supervised learning, unsupervised learning, and reinforcement learning.

[0958] Supervised learning refers to a method of training an artificial neural network with labels given for training data, where the labels can indicate the correct answers (or result values) that the artificial neural network needs to infer when the training data is input into the artificial neural network. Unsupervised learning can refer to a method of training an artificial neural network without labels given for training data. Reinforcement learning can refer to a training method of defining an agent in an environment to select actions or sequences of actions to maximize the cumulative reward in each state.

[0959] Machine learning implemented using a deep neural network (DNN) including multiple hidden layers among artificial neural networks is called deep learning, and deep learning is part of machine learning. Hereinafter, machine learning is explained to include deep learning.

[0960] The above technical features can be applied to the wireless communication of robots.

[0961] A robot can refer to a machine that automatically processes or operates a given task with its own capabilities. Specifically, a robot with the function of recognizing the environment and making autonomous judgments to perform operations can be called an intelligent robot.

[0962] Robots can be classified into industrial, medical, household, military robots, etc. according to their uses or fields. A robot can include actuators or drivers, which include motors to perform various physical operations (e.g., moving robot joints). In addition, a mobile robot can include wheels, brakes, thrusters, etc. in the driver to travel on the ground or fly in the air through the driver.

[0963] The above technical features can be applied to devices supporting extended reality.

[0964] Extended reality generally refers to virtual reality (VR), augmented reality (AR), and mixed reality (MR). VR technology is a computer graphics technology that provides real-world objects and backgrounds only in CG images, AR technology is a computer graphics technology that provides virtual CG images on real object images, and MR technology is a computer graphics technology that provides virtual objects mixed and combined with the real world.

[0965] The similarity between MR technology and AR technology is that real objects and virtual objects are displayed together. However, in AR technology, virtual objects are used as supplements to real objects, while in MR technology, virtual objects and real objects are in an equal state.

[0966] XR technology can be applied to head-mounted displays (HMDs), head-up displays (HUDs), mobile phones, tablet PCs, laptop computers, desktop computers, TVs, digital signage, etc. Devices applying XR technology can be called XR devices.

[0967] The claims recited in this specification can be combined in various ways. For example, the technical features of the method claims in this specification can be combined to be implemented as a device, and the technical features of the device claims in this specification can be combined to be implemented by a method. Additionally, the technical features of the method claims and the technical features of the device claims in this specification can be combined to be implemented as a device, and the technical features of the method claims and the technical features of the device claims in this specification can be combined to be implemented by a method.

Claims

1. A method performed by a non - access - point non - AP multi - link device (MLD) in a wireless local area network (WLAN) system, the method comprising the following steps: Sending, by a first non - AP station (STA) included in the non - AP MLD, a probe request frame for requesting at least one element related to a second link to a first access point (AP) included in an access - point AP MLD, wherein the first non - AP STA operates in a first link, wherein the non - AP MLD further includes a second non - AP STA operating in the second link, and wherein the probe request frame includes link identifier (ID) information related to the second link and 1 - bit information related to whether the at least one element is a complete set; and Receiving, by the first non - AP STA from the first AP, a response frame based on the probe request frame, wherein the response frame includes information related to simultaneous transmit and receive (STR) capability information between links.

2. The method according to claim 1, wherein, The probe request frame includes an information field comprising a first field and a second field, wherein the first field includes information for identifying elements requested for all links operating in the AP multi - link device, and wherein the second field includes information for identifying elements requested only for the second link.

3. The method according to claim 1, wherein, The at least one element is included in an element set designated for the second link.

4. The method according to claim 1, wherein The 1 - bit information is adjacent to the link ID information.

5. A method performed by an access - point AP multi - link device (MLD) in a wireless local area network (WLAN) system, the method comprising the following steps: Receiving, by a first access point (AP) included in the AP MLD, a probe request frame for requesting at least one element related to a second link from a first non - AP station (STA) in a non - AP MLD, wherein the first AP operates in a first link, wherein the AP MLD further includes a second AP operating in the second link, and wherein the probe request frame includes link identifier (ID) information related to the second link and 1 - bit information related to whether the at least one element is a complete set; and Sending, by the first AP, a response frame to the first STA based on the probe request frame, wherein the response frame includes information related to simultaneous transmit and receive (STR) capability information between links.

6. The method according to claim 5, wherein, The AP MLD is further configured to perform the steps of the method according to any one of claims 2 to 4.

7. A non - access - point non - AP multi - link device (MLD) in a wireless local area network (WLAN) system, the MLD comprising: A transceiver for transmitting and / or receiving wireless signals; And A processor operatively connected to the transceiver, wherein the processor is configured to: A probe request frame for requesting at least one element related to a second link is sent from a first non-AP station STA included in the non-AP MLD to a first AP included in the access point AP MLD, where the first non-AP STA operates in a first link, where the non-AP MLD further includes a second non-AP STA operating in the second link, and where the probe request frame includes link identifier ID information related to the second link and 1-bit information related to whether the at least one element is a complete set; and Based on the probe request frame, a response frame is received by the first non-AP STA from the first AP, where the response frame includes information related to simultaneous transmit and receive STR capability information between links.

8. The MLD according to claim 7, wherein The processor is further configured to perform the steps of the method according to any one of claims 2 to 4.

9. An access point AP multi-link device MLD in a wireless local area network WLAN system, the MLD comprising: A transceiver for transmitting and / or receiving wireless signals; And A processor operatively connected to the transceiver, where the processor is configured to: Receive, by a first access point AP included in the AP MLD, a probe request frame for requesting at least one element related to a second link from a first non-AP station STA in the non-AP MLD, where the first AP operates in a first link, where the AP MLD further includes a second AP operating in the second link, and where the probe request frame includes link identifier ID information related to the second link and 1-bit information related to whether the at least one element is a complete set; and Based on the probe request frame, a response frame is sent by the first AP to the first STA, where the response frame includes information related to simultaneous transmit and receive STR capability information between links.

10. The MLD according to claim 9, wherein, The processor is further configured to perform the steps of the method according to any one of claims 2 to 4.

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