Method for performing multi-link communication in a wireless communication system

Abstract

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

Description

Technical Field

[0001] The present specification relates to a method of performing multi-link communication in a wireless local area network (WLAN) system, and more particularly, to a method of transmitting information about links in multi-link communication and a device supporting the method. Background Art

[0002] Wireless local area networks (WLANs) have 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.

[0003] This specification proposes technical features that can be used in new communication standards. For example, the new communication standard may be the ultra-high throughput (EHT) standard currently under discussion. The EHT standard may use newly proposed increased bandwidth, enhanced PHY layer protocol data unit (PPDU) structure, enhanced sequence, hybrid automatic repeat request (HARQ) scheme, etc. The EHT standard may be referred to as the IEEE 802.11be standard. Summary of the invention

[0004] Technical Purpose

[0005] In the EHT specification, in order to support high throughput and high data rate, operations such as wide bandwidth (eg, 160 / 320 MHz), 16 streams, and / or multi-link (or multi-band) may be used.

[0006] In the EHT specification, a device supporting multilink (i.e., a multilink device) can operate in multiple links. In order to switch the connected link, the multilink device may need to receive information about another link that is not a link included in the multiple links. In addition, while performing communication through the first link, the multilink device needs to receive information about at least one link among the multiple links.

[0007] Therefore, a multi-link device may require technical characteristics that enable the multi-link device to receive information about another link.

[0008] Technical Solution

[0009] According to various embodiments, a multi-link device (MLD) connected to multiple links including a first link may perform the following steps: sending a request frame including an information field for requesting at least one element related to a second link to an access point (AP) of the multi-link device through a first station (STA) included in the 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 a response frame from the first AP through the first STA based on the request frame, wherein the response frame includes the at least one element.

[0010] Effects of the present disclosure

[0011] STAs included in a multi-link device can transmit information related to other STAs in the multi-link device together through one link. Therefore, frame exchange overhead can be reduced. In addition, link usage efficiency of STAs can be increased and power consumption can be reduced.

[0012] In addition, the first STA included in the multi-link device may request partial information per link. For example, the first STA of the multi-link device may request partial information related to the second link, and then the first STA may receive the requested information. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 An example of a transmitting device and / or a receiving device of this specification is shown.

[0014] Figure 2 is a conceptual view showing the structure of a wireless local area network (WLAN).

[0015] Figure 3 Shows the general link establishment process.

[0016] Figure 4 An example of PPDU used in the IEEE standard is shown.

[0017] Figure 5 The layout of resource units (RUs) used in a frequency band of 20 MHz is shown.

[0018] Figure 6 The layout of RUs used in a frequency band of 40 MHz is shown.

[0019] Figure 7 The layout of RUs used in the 80 MHz frequency band is shown.

[0020] Figure 8 The structure of the HE-SIG-B field is shown.

[0021] Fig. 9An example is shown in which multiple user STAs are assigned to the same RU through the MU-MIMO scheme.

[0022] Fig.10 The operation based on UL-MU is shown.

[0023] Fig.11 An example of a trigger frame is shown.

[0024] Fig.12 An example of a common information field of a trigger frame is shown.

[0025] Fig.13 An example of subfields included in the per-user information field is shown.

[0026] Fig.14 Describe the technical features of the UORA scheme.

[0027] Fig.15 An example of channels used / supported / defined in the 2.4 GHz band is shown.

[0028] Fig.16 Shows an example of channels used / supported / defined in the 5 GHz band.

[0029] Fig.17 Shows examples of channels used / supported / defined in the 6 GHz band.

[0030] Fig.18 An example of PPDU used in this specification is shown.

[0031] Fig.19 An example of a modified transmitting device and / or receiving device of the present specification is shown.

[0032] Fig. 20 An example of HE-PPDU is shown.

[0033] Fig.21 An example of channel bonding is shown.

[0034] Fig. 22 An exemplary structure of a non-AP MLD is shown.

[0035] Fig.23 An exemplary connection between an AP MLD and a non-AP MLD through a link establishment procedure is shown.

[0036] Fig.24 An example of a link being switched or reconnected is shown.

[0037] Fig.25 A detailed example showing a link being switched or reconnected.

[0038] Fig.26The operations of AP MLD and non-AP MLD for link switching or reconnection are shown.

[0039] Fig. 27 The operations of AP MLD and non-AP MLD for link switching or reconnection are shown.

[0040] Fig.28 The operations of AP MLD and non-AP MLD for link switching or reconnection are shown.

[0041] Fig.29 The operations of AP MLD and non-AP MLD for link switching or reconnection are shown.

[0042] Fig.30 Operations on a non-AP MLD for requesting information about other APs are shown.

[0043] Fig.31 A detailed example of the STA ratio per link is shown.

[0044] Fig.32 The operations of AP MLD and non-AP MLD for link switching or reconnection are shown.

[0045] Fig.33 The operations of AP MLD and non-AP MLD for link switching or reconnection are shown.

[0046] Fig.34 The operations of AP MLD and non-AP MLD for link switching or reconnection are shown.

[0047] Fig.35 An example of an MLD structure supporting an anchor link is shown.

[0048] Fig.36 An example of a situation where an anchor link switch or reconnection is required is shown.

[0049] Fig.37 The operation of AP MLD and non-AP MLD for anchor link switching or reconnection is shown.

[0050] Fig.38 and Fig.39 Detailed examples of elements for anchor link reconnection are respectively shown.

[0051] Fig.40 An example of a multi-link element is shown.

[0052] Fig.41 Another example of a multi-link element is shown.

[0053] Fig.42An example of the field configuration proposed in this specification is shown.

[0054] Fig.43 A detailed example showing the format of the request element.

[0055] Fig.44 A detailed example of the extended request element format is shown.

[0056] Fig.45 A detailed example of the PV1 Probe Response Option Element format is shown.

[0057] Fig.46 An example of an MLD request element is shown.

[0058] Fig.47 Another example of an MLD request element is shown.

[0059] Fig.48 Another example of an MLD request element is shown.

[0060] Fig.49 Another example of an MLD request element is shown.

[0061] Fig.50 Another example of an MLD request element is shown.

[0062] Fig.51 Another example of an MLD request element is shown.

[0063] Fig.52 Another example of an MLD request element is shown.

[0064] Fig.53 An example of an element for requesting public information is shown.

[0065] Fig.54 An example of a multilink element format is shown.

[0066] Fig.55 Another example of a multi-link element format is shown.

[0067] Fig.56 An example of the multi-link control field format is shown.

[0068] Fig.57 An example of the multi-link control field format is shown.

[0069] Fig.58 Another example of a multi-link element format is shown.

[0070] Fig.59 Another example of a multi-link element format is shown.

[0071] Fig.60 An example of a multilink element format and additional elements is shown.

[0072] Fig.61 Another example of a multilink element format and additional elements is shown.

[0073] Fig.62 An example of the multi-link control field format is shown.

[0074] Fig.63 Another example of a multi-link element format is shown.

[0075] Fig.64 Another example of a multi-link element format is shown.

[0076] Fig.65 Another example of a multi-link element format is shown.

[0077] Fig.66 and Fig.67 An example of an MLD change sequence element format is shown.

[0078] Fig.68 Another example of a multi-link element format is shown.

[0079] Fig.69 Shows an example of changing the format of a sequence element.

[0080] Fig.70 Another example of a multi-link element format is shown.

[0081] Fig.71 Another example of a multi-link element format is shown.

[0082] Fig.72 Another example of a multi-link element format is shown.

[0083] Fig.73 Another example of a multi-link element format is shown.

[0084] Fig.74 Another example of a multi-link element format is shown.

[0085] Fig.75 is a flow chart describing the operation of a multi-link device.

[0086] Fig.76 is a flow chart describing the operation of an AP multi-link device. DETAILED DESCRIPTION

[0087] 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" may 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".

[0088] A slash ( / ) or a comma used in this specification may represent "and / or". For example, "A / B" may represent "A and / or B". Thus, "A / B" may represent "only A", "only B", or "both A and B". For example, "A, B, C" may represent "A, B, or C".

[0089] In the present specification, "at least one of A and B" may mean "only A", "only B", or "both A and B". In addition, in the present 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".

[0090] In addition, in the present specification, "at least one of A, B, and C" may mean "only A", "only B", "only C", or "any combination of A, B, and C". In addition, "at least one of A, B, or C" or "at least one of A, B and / or C" may mean "at least one of A, B, and C".

[0091] In addition, the brackets used in this specification may mean "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" of this specification is not limited to "EHT-signal", and "EHT-signal" may be proposed as an example of "control information". In addition, when indicated as "control information (ie, EHT signal)", it may also mean that "EHT signal" is proposed as an example of "control information".

[0092] Technical features described separately in one drawing of the present specification may be implemented separately or simultaneously.

[0093] The following examples of this specification can be applied to various wireless communication systems. For example, the following examples of this specification can be applied to wireless local area network (WLAN) systems. For example, this specification can be applied to IEEE 802.11a / g / n / ac standards or IEEE802.11ax standards. In addition, this specification can also be applied to the newly proposed EHT standard or IEEE 802.11be standard. In addition, the examples of this specification can also be applied to new WLAN standards enhanced from the EHT standard or the IEEE 802.11be standard. In addition, the examples of this specification can be applied to mobile communication systems. For example, it can be applied to long-term evolution (LTE) based on the 3rd Generation Partnership Project (3GPP) standard and mobile communication systems based on the evolution of LTE. In addition, the examples of this specification can be applied to communication systems based on the 5G NR standard of the 3GPP standard.

[0094] Hereinafter, in order to describe the technical features of the present specification, technical features applicable to the present specification will be described.

[0095] Figure 1 An example of a transmitting device and / or a receiving device of this specification is shown.

[0096] exist Figure 1 In the example, various technical features described below can be performed. Figure 1 At least one station (STA) is involved. For example, the STAs 110 and 120 of this specification may also be referred to as various terms such as mobile terminals, wireless devices, wireless transmit / receive units (WTRUs), user equipment (UEs), mobile stations (MSs), mobile subscriber units, or simply as users. The STAs 110 and 120 of this specification may also be referred to as various terms such as networks, base stations, node Bs, access points (APs), repeaters, routers, repeaters, etc. The STAs 110 and 120 of this specification may also be referred to as various names such as receiving devices, transmitting devices, receiving STAs, transmitting STAs, receiving devices, transmitting devices, etc.

[0097] For example, the STAs 110 and 120 may function as an AP or a non-AP. That is, the STAs 110 and 120 of the present specification may function as an AP and / or a non-AP.

[0098] In addition to the IEEE 802.11 standard, the STAs 110 and 120 of the present specification may support various communication standards together. For example, communication standards based on 3GPP standards (e.g., LTE, LTE-A, 5G NR standards), etc. may be supported. In addition, the STAs of the present specification may be implemented as various devices such as mobile phones, vehicles, personal computers, etc. In addition, the STAs of the present specification may support communication for various communication services such as voice calls, video calls, data communications, and self-driving (autonomous driving).

[0099] The STAs 110 and 120 of the present specification may include a medium access control (MAC) compliant with the IEEE 802.11 standard and a physical layer interface for a radio medium.

[0100] The following will refer to Figure 1 STAs 110 and 120 are described in sub-figure (a) of FIG.

[0101] The first STA 110 may include a processor 111, a memory 112, and a transceiver 113. The processing, memory, and transceiver shown may be separately implemented as separate chips, or at least two blocks / functions may be implemented by a single chip.

[0102] The transceiver 113 of the first STA performs a signal transmission / reception operation. Specifically, it can transmit / receive IEEE802.11 packets (e.g., IEEE 802.11a / b / g / n / ac / ax / be, etc.).

[0103] For example, the first STA 110 may perform operations expected by the AP. For example, the processor 111 of the AP may receive a signal through the transceiver 113, process a received (RX) signal, generate a transmitted (TX) signal, and provide control for signal transmission. The memory 112 of the AP may store a signal (e.g., an RX signal) received through the transceiver 113, and may store a signal (e.g., a TX signal) to be transmitted through the transceiver.

[0104] For example, the second STA 120 can perform operations expected by the 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.

[0105] For example, the processor 121 of the non-AP STA may receive a signal through the transceiver 123, process the RX signal, generate a TX signal, and provide control for signal transmission. The memory 122 of the non-AP STA may store a signal (e.g., an RX signal) received through the transceiver 123, and may store a signal (e.g., a TX signal) to be transmitted through the transceiver.

[0106] For example, the operation of a device indicated as an AP in the specification described below may be performed in the first STA 110 or the second STA 120. For example, if the first STA 110 is an AP, the operation of the device indicated as the AP may be controlled by the processor 111 of the first STA 110, and the relevant signal may be transmitted or received by the transceiver 113 controlled by the processor 111 of the first STA 110. In addition, control information related to the operation of the AP or the TX / RX signal of the AP may be stored in the memory 112 of the first STA 110. In addition, if the second STA 120 is an AP, the operation of the device indicated as the AP may be controlled by the processor 121 of the second STA 120, and the relevant signal may be transmitted or received by the transceiver 123 controlled by the processor 121 of the second STA 120. In addition, control information related to the operation of the AP or the TX / RX signal of the AP may be stored in the memory 122 of the second STA 120.

[0107] For example, in the specification described below, the operation of the device indicated as a non-AP (or user STA) may be performed in the first STA 110 or the second STA 120. For example, if the second STA 120 is a non-AP, the operation of the device indicated as the non-AP may be controlled by the processor 121 of the second STA 120, and the relevant signal may be transmitted or received by the transceiver 123 controlled by the processor 121 of the second STA 120. In addition, the control information related to the operation of the non-AP or the TX / RX signal of the non-AP may be stored in the memory 122 of the second STA 120. For example, if the first STA 110 is a non-AP, the operation of the device indicated as the non-AP may be controlled by the processor 111 of the first STA 110, and the relevant signal may be transmitted or received by the transceiver 113 controlled by the processor 111 of the first STA 110. In addition, the control information related to the operation of the non-AP or the TX / RX signal of the non-AP may be stored in the memory 112 of the first STA 110.

[0108] In the specification described below, devices referred to as (transmitting / receiving) STA, first STA, second STA, STA1, STA2, AP, first AP, second AP, AP1, AP2, (transmitting / receiving) terminal, (transmitting / receiving) device, (transmitting / receiving) apparatus, network, etc. may refer to Figure 1 For example, a device indicated as (transmitting / receiving) STA, a first STA, a second STA, STA1, STA2, AP, a first AP, a second AP, AP1, AP2, a (transmitting / receiving) terminal, a (transmitting / receiving) device, a (transmitting / receiving) apparatus, a network, etc. (but without a specific number) may refer to Figure 1 For example, in the following example, the operation of various STAs sending / receiving signals (eg, PPDU) may be performed in Figure 1 In addition, in the following examples, various STAs generate TX / RX signals or perform data processing and calculations in advance for TX / RX signals. Figure 1111 and 121 of the processors. For example, examples of operations for generating TX / RX signals or performing data processing and calculation in advance may include: 1) operations for determining / obtaining / configuring / calculating / decoding / encoding bit information of subfields (SIG, STF, LTF, data) included in the PPDU; 2) operations for determining / configuring / obtaining time resources or frequency resources (e.g., subcarrier resources) for subfields (SIG, STF, LTF, data) included in the PPDU; 3) operations for determining / configuring / obtaining specific sequences (e.g., pilot sequences, STF / LTF sequences, additional sequences applied to SIG) for subfields (SIG, STF, LTF, data) included in the PPDU; 4) power control operations and / or power saving operations applied to STAs; and 5) operations related to determining / obtaining / configuring / decoding / encoding of ACK signals, etc. In addition, in the following examples, various information (e.g., information related to fields / subfields / control fields / parameters / power, etc.) used by various STAs to determine / obtain / configure / calculate / decode / encode TX / RX signals may be stored in Figure 1 in the memories 112 and 122.

[0109] Figure 1 The aforementioned device / STA of sub-graph (a) can be as follows Figure 1 In the following, we will modify the Figure 1 Sub-figure (b) of FIG. 1 is used to describe STA 110 and STA 120 of the present specification.

[0110] For example, Figure 1 The transceivers 113 and 123 shown in the sub-diagram (b) of FIG. Figure 1 The same functions as the aforementioned transceiver shown in sub-figure (a) of FIG. Figure 1 The processing chips 114 and 124 shown in sub-figure (b) may include processors 111 and 121 and memories 112 and 122 . Figure 1 The processors 111 and 121 and the memories 112 and 122 shown in the sub-diagram (b) of FIG. Figure 1 The processors 111 and 121 and memories 112 and 122 have the same functions as those shown in sub-figure (a) above.

[0111] The mobile terminal, wireless device, wireless transmit / receive unit (WTRU), user equipment (UE), mobile station (MS), mobile subscriber unit, user, user STA, network, base station, Node B, access point (AP), repeater, router, repeater, receiving unit, sending unit, receiving STA, sending STA, receiving device, sending device, receiving apparatus and / or sending apparatus described below may mean Figure 1 STAs 110 and 120 shown in sub-figures (a) / (b) of Figure 1 The processing chips 114 and 124 shown in the sub-figure (b) of FIG. That is, the technical features of this specification can be Figure 1 The STA 110 and 120 shown in the sub-figure (a) / (b) of FIG. 110 and 120 may be executed only in Figure 1 The processing chips 114 and 124 shown in the sub-figure (b) of Figure 1 For example, the technical feature of sending a control signal from a STA can be understood as the transceiver 113 and 123 shown in the sub-figure (a) / (b) of FIG. Figure 1 The transceiver 113 illustrated in the sub-figures (a) / (b) of FIG. 1 transmits the Figure 1 The technical features of the control signals generated in the processors 111 and 121 illustrated in the sub-figures (a) / (b) of FIG. Alternatively, the technical features of the sending STA sending the control signal can be understood as Figure 1 The technical features of the processing chips 114 and 124 shown in the sub-figure (b) of FIG. 10 are for generating control signals to be transmitted to the transceivers 113 and 123 .

[0112] For example, the technical feature of receiving the control signal by the receiving STA can be understood as Figure 1 The technical feature of the transceivers 113 and 123 receiving the control signal shown in the sub-figure (a) of FIG. 1 can be understood as the technical feature of the receiving STA receiving the control signal by Figure 1 The processors 111 and 121 shown in the sub-diagram (a) of Figure 1 Alternatively, the technical feature of the receiving STA receiving the control signal can be understood as the technical feature of the control signal received by the transceivers 113 and 123 shown in the sub-figure (a) of FIG. Figure 1 The processing chips 114 and 124 shown in the sub-figure (b) of Figure 1 Technical characteristics of the control signals received in transceivers 113 and 123 shown in sub-figure (b).

[0113] Reference Figure 1 As shown in sub-figure (b), software codes 115 and 125 may be included in memories 112 and 122. Software codes 115 and 126 may include instructions for controlling operations of processors 111 and 121. Software codes 115 and 125 may be included as various programming languages.

[0114] Figure 1 The processors 111 and 121 or the processing chips 114 and 124 may include an application specific integrated circuit (ASIC), other chipsets, logic circuits and / or data processing devices. The processor may 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 demodulator (modem). Figure 1 The processors 111 and 121 or the processing chips 114 and 124 may be composed of The SNAPDRAGONTM processor series manufactured by EXYNOSTM processor series manufactured by Processor family manufactured by The HELIOTM processor series manufactured by The ATOMTM processor family manufactured by or enhanced from these processors.

[0115] In this specification, 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. In addition, in this specification, 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.

[0116] Figure 2 is a conceptual diagram showing the structure of a wireless local area network (WLAN).

[0117] Figure 2 The upper part of shows the structure of an infrastructure basic service set (BSS) of the Institute of Electrical and Electronics Engineers (IEEE) 802.11.

[0118] Reference Figure 2 The wireless LAN system may include one or more infrastructure BSSs 200 and 205 (hereinafter referred to as BSSs). BSSs 200 and 205, which are a collection of APs and STAs (e.g., access point (AP) 225 and station (STA1) 200-1) that are successfully synchronized to communicate with each other, are not concepts indicating a specific area. BSSs 205 may include one or more STAs 205-1 and 205-2 that may join one AP 230.

[0119] The BSS may include at least one STA, an AP providing a distributed service, and a distribution system (DS) 210 connecting a plurality of APs.

[0120] The distribution system 210 may implement an extended service set (ESS) 240 extended by connecting a plurality of BSSs 200 and 205. The ESS 240 may be used as a term indicating one network configured by connecting one or more APs 225 or 230 via the distribution system 210. APs included in one ESS 240 may have the same service set identification (SSID).

[0121] The portal 220 may serve as a bridge connecting a wireless LAN network (IEEE 802.11) and another network (eg, 802.X).

[0122] exist Figure 2 In the BSS shown in the upper part of FIG, a network between the APs 225 and 230 and a network between the APs 225 and 230 and the STAs 200-1, 205-1, and 205-2 can be implemented. However, a network is configured between the STAs to perform communication even without the APs 225 and 230. A network that performs communication by configuring a network between the STAs even without the APs 225 and 230 is defined as an ad hoc network or an independent basic service set (IBSS).

[0123] Figure 2 The lower part of FIG. 1 shows a conceptual diagram illustrating an IBSS.

[0124] Reference Figure 2 In the lower part, the IBSS is a BSS operating in a self-organizing mode. Since the IBSS does not include an access point (AP), there is no centralized management entity that performs management functions in the center. That is, in the IBSS, STA 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.

[0125] Figure 3 Describe the general link establishment process.

[0126] In S310, the STA may perform a network discovery operation. The network discovery operation may include a scanning operation of the STA. That is, in order to access the network, the STA needs to discover participating networks. The STA needs to identify compatible networks before joining a wireless network, and the process of identifying a network present in a specific area is called scanning. Scanning methods include active scanning and passive scanning.

[0127] Figure 3The network discovery operation including active scanning processing is described. In active scanning, the STA performing the scan sends a probe request frame and waits for a response to the probe request frame in order to identify which AP exists around while moving to the channel. 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 may be the STA that sent the last beacon frame in the BSS of the channel being scanned. In the BSS, since the AP sends a beacon frame, the AP is the responder. In the 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 may store the BSS-related information included in the received probe response frame, may move to the next channel (e.g., channel 2), and may perform scanning by the same method (e.g., sending a probe request and receiving a probe response via channel 2).

[0128] 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 a beacon frame while moving to a channel. The beacon frame is one of the management frames in IEEE 802.11 and is periodically sent to indicate the existence of a wireless network and enable the STA performing the scan to find the wireless network and join the wireless network. In the BSS, the AP is used to periodically send beacon frames. In the IBSS, the STAs in the IBSS take turns sending beacon frames. Upon receiving the beacon frame, the STA performing the scan stores 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, can move to the next channel, and can perform scanning in the next channel by the same method.

[0129] After discovering the network, the STA may perform an authentication process in S320. This authentication process may be referred to as a first authentication process to clearly distinguish it from the security establishment operation in the subsequent S340. The authentication process in S320 may include a process in which the STA sends an authentication request frame to the AP and the AP sends an authentication response frame to the STA in response. The authentication frame used for the authentication request / response is a management frame.

[0130] The authentication frame may include information about the authentication algorithm number, authentication transaction sequence number, status code, challenge text, robust security network (RSN), and limited cycle group.

[0131] The STA may send an authentication request frame to the AP. The AP may determine whether to allow authentication of the STA based on information included in the received authentication request frame. The AP may provide the STA with an authentication process result via an authentication response frame.

[0132] When the STA is successfully authenticated, the STA may perform an association process in S330. The association process includes a process in which the STA sends an association request frame to the AP and the AP sends an association response frame to the STA in 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, RSN, a mobile domain, a supported operation category, a traffic indication map (TIM) broadcast request, and interworking service capabilities. 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 mobile domain, a timeout interval (association recovery time), overlapping BSS scanning parameters, a TIM broadcast response, and a QoS map.

[0133] In S340, the STA may perform a security establishment process. The security establishment process in S340 may include a process of establishing a private key through a four-way handshake (eg, through an Extensible Authentication Protocol over LAN (EAPOL) frame).

[0134] Figure 4 An example of PPDU used in the IEEE standard is described.

[0135] As shown, various types of PHY protocol data units (PPDUs) are used in the IEEE a / g / n / ac standards. Specifically, LTF and STF include training signals, SIG-A and SIG-B include control information for receiving STAs, and the data field includes user data corresponding to PSDU (MAC PDU / aggregated MAC PDU).

[0136] Figure 4 An example of HE PPDU according to IEEE 802.11ax is also included. Figure 4 The HE PPDU of is an exemplary PPDU for multiple users. The HE-SIG-B may be included only in the PPDU for multiple users, and the HE-SIG-B may be omitted in the PPDU for a single user.

[0137] like Figure 4As shown, the HE-PPDU for multiple users (MU) 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 time period shown (ie, 4 or 8 μs).

[0138] The following describes a resource unit (RU) for a PPDU. A RU may include multiple subcarriers (or tones). A RU may be used to send signals to multiple STAs according to OFDMA. In addition, a RU may also be defined as sending a signal to one STA. A RU may be used for an STF, an LTF, a data field, etc.

[0139] Figure 5 The layout of resource units (RU) used in a 20 MHz frequency band will be described.

[0140] like Figure 5 As shown, resource units (RUs) corresponding to different numbers of tones (i.e., subcarriers) may be used to form some fields of the HE-PPDU. For example, resources may be allocated for the HE-STF, HE-LTF, and data fields in the RU shown.

[0141] like Figure 5 As shown in the uppermost part of , 26 units (i.e., units corresponding to 26 tones) may be set. Six tones may be used for a guard band in the leftmost band of the 20 MHz band, and five tones may be used for a guard band in the rightmost band of the 20 MHz band. In addition, seven DC tones may be inserted in the center band (i.e., the DC band), and 26 units corresponding to 13 tones on each of the left and right sides of the DC band may be set. 26 units, 52 units, and 106 units may be allocated to other bands. Each unit may be allocated to a receiving STA (i.e., a user).

[0142] Figure 5 The layout of the RU in can be used not only for multiple users (MU) but also for a single user (SU), in which case one 242 unit can be used and three DC tones can be inserted, such as Figure 5 shown at the bottom.

[0143] although Figure 5RUs of various sizes are proposed, namely, 26-RU, 52-RU, 106-RU, and 242-RU, but RUs of a particular size may be expanded or increased. Therefore, the present embodiment is not limited to a particular size of each RU (ie, the number of corresponding tones).

[0144] Figure 6 The layout of RUs used in the 40 MHz frequency band is described.

[0145] Similar to using RUs with various sizes Figure 5 ,exist Figure 6 In the example of 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, etc., can be used. In addition, five DC tones can be inserted in the center frequency, 12 tones can be used for the guard band in the leftmost band of the 40MHz band, and 11 tones can be used for the guard band in the rightmost band of the 40MHz band.

[0146] like Figure 6 As shown in FIG. 4, when the RU layout is used for a single user, 484-RU can be used. The specific number of RUs can be similar to Figure 5 Change.

[0147] Figure 7 The layout of RUs used in the 80 MHz frequency band is described.

[0148] Similar to using RUs with various sizes Figure 5 and Figure 6 ,exist Figure 7 In the example of 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, 996-RU, etc., 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, 996-RU, etc. may be used. In addition, seven DC tones may be inserted in the center frequency, 12 tones may be used for a guard band in the leftmost band of the 80 MHz band, and 11 tones may be used for a guard band in the rightmost band of the 80 MHz band. In addition, 26-RU corresponding to 13 tones on each side of the left and right sides of the DC band may be used.

[0149] like Figure 7 As shown, when the RU layout is for a single user, a 996-RU can be used, in which case five DC tones can be inserted.

[0150] The RU described in this specification can be used in 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 the first STA through a trigger frame, and can allocate a second RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to the second STA. Thereafter, the first STA can send a first triggered-based PPDU based on the first RU, and the second STA can send a second triggered-based PPDU based on the second RU. The first / second triggered-based PPDUs are sent to the AP in the same (or overlapping) time period.

[0151] For example, when configuring a DL MU PPDU, the transmitting STA (e.g., AP) may allocate a first RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to the first STA, and may allocate a second RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to the second STA. That is, the transmitting STA (e.g., AP) may transmit the HE-STF, HE-LTF, and data fields for the first STA through the first RU in one MU PPDU, and may transmit the HE-STF, HE-LTF, and data fields for the second STA through the second RU.

[0152] Information about the layout of RUs may be signaled via HE-SIG-B.

[0153] Figure 8 Describe the structure of the HE-SIG-B field.

[0154] As shown, the HE-SIG-B field 810 includes a common field 820 and a user-specific field 830. The common field 820 may include information commonly applied to all users (i.e., user STAs) receiving the SIG-B. The user-specific field 830 may be referred to as a user-specific control field. When the SIG-B is transmitted to multiple users, the user-specific field 830 may be applied only to any one of the multiple users.

[0155] like Figure 8 As shown, the common field 820 and the user-specific field 830 may be encoded separately.

[0156] The common field 820 may include N*8 bits of RU allocation information. For example, the RU allocation information may include information related to the location of the RU. For example, when Figure 5 When a 20 MHz channel is used as shown, the RU allocation information may include information on a specific frequency band where a specific RU (26-RU / 52-RU / 106-RU) is arranged.

[0157] An example of the case where the RU allocation information consists of 8 bits is as follows.

[0158] [Table 1]

[0159]

[0160] like Figure 5 As shown in the example of , up to nine 26-RUs can be allocated to a 20MHz 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., 20MHz). In addition, 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 Figure 5 In the example of , a 52-RU may be allocated to the far right, and seven 26-RUs may be allocated to its left.

[0161] The example of Table 1 shows only some RU locations where RU allocation information can be displayed.

[0162] For example, the RU allocation information may include the example in Table 2 below.

[0163] [Table 2]

[0164]

[0165] "01000y2y1y0" relates to an example in which a 106-RU is allocated to the leftmost side of a 20 MHz channel and five 26-RUs are allocated to the right thereof. 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 the 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 may be N+1.

[0166] Generally, multiple STAs (eg, user STAs) different from each other may be allocated to multiple RUs. However, multiple STAs (eg, user STAs) may be allocated to one or more RUs having at least a specific size (eg, 106 subcarriers) based on the MU-MIMO scheme.

[0167] like 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 can be determined based on the RU allocation information of the common field 820. For example, when the RU allocation information of the common field 820 is "00000000", one user STA can be allocated to each of the nine 26-RUs (e.g., nine user STAs can be allocated). That is, up to 9 user STAs can be allocated to a specific channel through the OFDMA scheme. In other words, up to 9 user STAs can be allocated to a specific channel through a non-MU-MIMO scheme.

[0168] For example, when RU allocation is set to "01000y2y1y0", multiple STAs can be allocated to the 106-RU arranged on the leftmost side through the MU-MIMO scheme, and five user STAs can be allocated to the five 26-RUs arranged on the right side thereof through the non-MU MIMO scheme. Fig. 9 .

[0169] Fig. 9 An example of allocating multiple user STAs to the same RU through the MU-MIMO scheme is described.

[0170] For example, when Fig. 9 When the RU allocation is set to "01000010", the 106-RU can be allocated to the leftmost side of a specific channel, and five 26-RUs can be allocated to its right side. In addition, three user STAs can be allocated to the 106-RU through the MU-MIMO scheme. As a result, since eight user STAs are allocated, the user-specific field 830 of the HE-SIG-B can include eight user fields.

[0171] Eight user fields can be pressed Fig. 9 In addition, Figure 8 As shown, two user fields can be implemented using one user block field.

[0172] Figure 8 and Fig. 9 The user field shown may be configured based on two formats. That is, the user field related to the MU-MIMO scheme may be configured in a first format, and the user field related to the non-MIMO scheme may be configured in a second format. Fig. 9 In the example of , user field 1 to user field 3 may be based on the first format, and user field 4 to user field 8 may be based on the second format. The first format or the second format may include bit information of the same length (eg, 21 bits).

[0173] Each user field may have the same size (eg, 21 bits). For example, the user field of the first format (first MU-MIMO scheme) may be configured as follows.

[0174] For example, the first bit (i.e., B0-B10) in the user field (i.e., 21 bits) may include identification information (e.g., STA-ID, partial AID, etc.) of the user STA that allocates the corresponding user field. In addition, the second bit (i.e., B11-B14) in the user field (i.e., 21 bits) may include information related to the space configuration. Specifically, examples of the second bit (i.e., B11-B14) may be shown in Tables 3 and 4 below.

[0175] [Table 3]

[0176]

[0177] [Table 4]

[0178]

[0179] As shown in Table 3 and / or Table 4, the second bits (e.g., B11-B14) may include information related to the number of spatial streams allocated to multiple user STAs allocated based on the MU-MIMO scheme. Fig. 9 When three user STAs are allocated to 106-RU based on the MU-MIMO scheme, 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 Fig. 9 In the example of , four spatial streams may be allocated to user field 1, one spatial stream may be allocated to user field 1, and one spatial stream may be allocated to user field 3.

[0180] As shown in the examples of Table 3 and / or Table 4, the information about the number of spatial streams for the user STA (i.e., the second bits, B11-B14) may consist of 4 bits. In addition, the information about the number of spatial streams for the user STA (i.e., the second bits, B11-B14) may support up to eight spatial streams. In addition, the information about the number of spatial streams for the user STA (i.e., the second bits, B11-B14) may support up to four spatial streams for one user STA.

[0181] In addition, the third bit (ie, B15-18) in the user field (ie, 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.

[0182] The MCS, MCS information, MCS index, MCS field, etc. used in this specification may be indicated by an index value. 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.

[0183] In addition, the fourth bit (ie, B19) in the user field (ie, 21 bits) may be a reserved field.

[0184] In addition, the fifth bit (ie, B20) in the user field (ie, 21 bits) may include information on the coding type (eg, BCC or LDPC). That is, the fifth bit (ie, B20) may include information on the type of channel coding (eg, BCC or LDPC) applied to the data field in the PPDU including the corresponding SIG-B.

[0185] The above example relates to a user field in the first format (format of the MU-MIMO scheme). An example of a user field in the second format (format of the non-MU-MIMO scheme) is as follows.

[0186] The first bit (e.g., B0-B10) in the user field of the second format may include 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 a beamforming steering matrix is ​​applied. 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 dual carrier modulation (DCM) is applied. 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).

[0187] Fig.10UL-MU-based operation is shown. As shown, a transmitting STA (e.g., an AP) may perform channel access through contention (e.g., a backoff operation), and may transmit a trigger frame 1030. That is, the transmitting STA may transmit a PPDU including a trigger frame 1030. Upon receiving a PPDU including a trigger frame, a trigger-based (TB) PPDU is transmitted after a delay corresponding to SIFS.

[0188] The TB PPDUs 1041 and 1042 may be transmitted at the same time period, and may be transmitted from a plurality of STAs (eg, user STAs) having the AID indicated in the trigger frame 1030. The ACK frame 1050 for the TB PPDU may be implemented in various forms.

[0189] Reference Figures 11 to 13 Describes specific features of the trigger frame. Even when UL-MU communication is used, an Orthogonal Frequency Division Multiple Access (OFDMA) scheme or a MU-MIMO scheme may be used, and OFDMA and MU-MIMO schemes may be used simultaneously.

[0190] Fig.11 An example of a trigger frame is shown. Fig.11 The trigger frame allocates resources for uplink multi-user (MU) transmission and may be sent, for example, from an AP. The trigger frame may be configured by a MAC frame and may be included in a PPDU.

[0191] Fig.11 The various fields shown may be partially omitted, and another field may be added. In addition, the length of each field may be changed to be different from that shown in the figure.

[0192] Fig.11 The frame control field 1110 may include information related to the MAC protocol version and additional additional control information. The duration field 1120 may include time information configured by the NAV or information related to an identifier (eg, AID) of the STA.

[0193] In addition, the RA field 1130 may include address information of the receiving STA of the corresponding trigger frame, and may be optionally omitted. The TA field 1140 may include address information of the STA (e.g., AP) that sends the corresponding trigger frame. The public information field 1150 includes public control information applied to the receiving STA that receives the corresponding trigger frame. For example, a field indicating the length of the L-SIG field of the uplink PPDU sent 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 sent in response to the corresponding trigger frame may be included. In addition, as public control information, information related to the length of the CP of the uplink PPDU sent in response to the corresponding trigger frame or information related to the length of the LTF field may be included.

[0194] In addition, preferably including and receiving Fig.11 The number of receiving STAs of the trigger frame corresponds to the per-user information fields 1160#1 to 1160#N. The per-user information field may also be referred to as an "allocation field".

[0195] in addition, Fig.11 The trigger frame may include a padding field 1170 and a frame check sequence field 1180 .

[0196] Fig.11 Each of the illustrated per-user information fields 1160#1 to 1160#N may include a plurality of subfields.

[0197] Fig.12 An example illustrating the common information field of a trigger frame. Fig.12 The subfields of may be partially omitted, and additional subfields may be added. In addition, the lengths of the various subfields shown may be changed.

[0198] The length field 1210 shown has the same value as the length field of the L-SIG field of the uplink PPDU sent 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.

[0199] In addition, the tandem identifier field 1220 indicates whether a tandem operation is performed. The tandem operation means that downlink MU transmission and uplink MU transmission are performed together in the same TXOP. That is, it means that downlink MU transmission is performed, and then uplink MU transmission is performed after a preset time (e.g., SIFS). During the tandem operation, only one transmitting device (e.g., AP) can perform downlink communication, and multiple transmitting devices (e.g., non-AP) can perform uplink communication.

[0200] The CS request field 1230 indicates whether a wireless medium status or NAV, etc. must be considered in case that a reception device that has received a corresponding trigger frame transmits a corresponding uplink PPDU.

[0201] The HE-SIG-A information field 1240 may include information for controlling the content of the SIG-A field (ie, HE-SIG-A field) of the uplink PPDU in response to the corresponding trigger frame.

[0202] The CP and LTF type field 1250 may include information related to the CP length and LTF length of the uplink PPDU sent 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 beamforming trigger, requesting a block ACK / NACK, etc.

[0203] It can be assumed that the trigger type field 1260 of the trigger frame in this specification indicates a basic type of trigger frame for a typical trigger. For example, the basic type of trigger frame can be referred to as a basic trigger frame.

[0204] Fig.13 An example of subfields included in the per-user information field is described. Fig.13 The user information field 1300 may be understood as referring to the above Fig.11 Any of the per-user information fields 1160#1 to 1160#N mentioned above. Included in Fig.13 The subfields in the user information field 1300 may be partially omitted, and additional subfields may be added. In addition, the length of each subfield shown may be changed.

[0205] Fig.13 The user identifier field 1310 indicates an identifier of the STA (ie, the receiving STA) corresponding to the per-user information. An example of the identifier may be all or part of an association identifier (AID) value of the receiving STA.

[0206] In addition, the RU allocation field 1320 may be included. That is, when the receiving STA identified by the user identifier field 1310 transmits a TB PPDU in response to the trigger frame, the TB PPDU is transmitted 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 RU shown.

[0207] Fig.13The subfield of may include a coding type field 1330. The coding type field 1330 may indicate the coding type of the TB PPDU. For example, when BCC coding is applied to the TB PPDU, the coding type field 1330 may be set to "1", and when LDPC coding is applied, the coding type field 1330 may be set to "0".

[0208] in addition, Fig.13 The subfield of may include an MCS field 1340. The MCS field 1340 may indicate the MCS scheme applied to the TB PPDU. For example, when BCC coding is applied to the TB PPDU, the coding type field 1330 may be set to "1", and when LDPC coding is applied, the coding type field 1330 may be set to "0".

[0209] Hereinafter, a UL OFDMA-based random access (UORA) scheme will be described.

[0210] Fig.14 Describe the technical features of the UORA scheme.

[0211] The sending STA (e.g., AP) can Fig.14 Specifically, the AP may allocate the first RU resource (AID 0, RU 1), the second RU resource (AID 0, RU 2), the third RU resource (AID 0, RU 3), the fourth RU resource (AID 2045, RU 4), ​​the fifth RU resource (AID 2045, RU 5), and the sixth 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 information related to RU 1 to RU 6 may be included in, for example, the user identifier field 1310. Fig.13 AID=0 may mean UORA resources for associated STAs, and AID=2045 may mean UORA resources for non-associated STAs. Fig.14 The 1st to 3rd RU resources can be used as UORA resources for associated STAs. Fig.14 The 4th RU resource and the 5th RU resource can be used as UORA resources for non-associated STAs. Fig.14 The 6th RU resources may be used as typical resources for UL MU.

[0212] exist Fig.14In the example, STA1's OFDMA random access backoff (OBO) is reduced to 0, and STA1 randomly selects the second RU resource (AID 0, RU 2). In addition, since STA2 / 3's OBO counter is greater than 0, no uplink resources are allocated to STA2 / 3. Fig.14 For STA4 in , since the AID of STA4 (eg, AID=3) is included in the trigger frame, resources of RU 6 are allocated without backoff.

[0213] Specifically, due to Fig.14 STA1 is the associated STA, so the total number of qualified RA RUs for STA1 is 3 (RU1, RU 2, and RU 3), so STA1 decrements the OBO counter by 3 to make the OBO counter 0. In addition, since Fig.14 STA2 is the associated STA, so the total number of eligible RA RUs for STA2 is 3 (RU 1, RU 2, and RU 3), so STA2 decrements the OBO counter by 3, but the OBO counter is greater than 0. In addition, due to Fig.14 STA3 is a non-associated STA, so the total number of eligible RA RUs for STA3 is 2 (RU 4, RU 5), and therefore STA3 decrements the OBO counter by 2, but the OBO counter is greater than 0.

[0214] Fig.15 Illustrate examples of channels used / supported / defined in the 2.4 GHz band.

[0215] The 2.4 GHz band may be referred to by other terms such as a first frequency band. In addition, the 2.4 GHz band may mean a frequency domain that uses / supports / defines channels having center frequencies close to 2.4 GHz (eg, channels having center frequencies within 2.4 to 2.5 GHz).

[0216] Multiple 20 MHz channels may be included in the 2.4 GHz band. 20 MHz within 2.4 GHz may have multiple channel indices (e.g., index 1 to index 14). For example, the center frequency of a 20 MHz channel assigned with channel index 1 may be 2.412 GHz, the center frequency of a 20 MHz channel assigned with channel index 2 may be 2.417 GHz, and the center frequency of a 20 MHz channel assigned with channel index N may be (2.407+0.005*N) GHz. Channel indices may be referred to as various terms such as channel numbers. The specific values ​​of channel indices and center frequencies may vary.

[0217] Fig.15An example is given of 4 channels within the 2.4 GHz frequency band. Each of the 1st frequency domain 1510 to the 4th frequency domain 1540 shown herein may include one channel. For example, the 1st 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 2nd frequency domain 1520 may include channel 6. In this case, the center frequency of channel 6 may be set to 2437 MHz. The 3rd frequency domain 1530 may include channel 11. In this case, the center frequency of channel 11 may be set to 2462 MHz. The 4th frequency domain 1540 may include channel 14. In this case, the center frequency of channel 14 may be set to 2484 MHz.

[0218] Fig.16 Illustrate examples of channels used / supported / defined in the 5 GHz band.

[0219] The 5 GHz band may be referred to as other terms such as a second frequency band, etc. 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 varied.

[0220] Multiple channels within the 5 GHz band include Unlicensed National Information Infrastructure (UNII)-1, UNII-2, UNII-3, and ISM. UNII-1 may be referred to as UNII Low. UNII-2 may include frequency domains referred to as UNII Mid and UNII-2 Extended. UNII-3 may be referred to as UNII-Upper.

[0221] A plurality of channels may be configured within the 5 GHz frequency 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 5170 MHz to 5330 MHz frequency domain / range within UNII-1 and UNII-2 may be divided into eight 20 MHz channels. The 5170 MHz to 5330 MHz frequency domain / range may be divided into four channels via a 40 MHz frequency domain. The 5170 MHz to 5330 MHz frequency domain / range may be divided into two channels via an 80 MHz frequency domain. Alternatively, the 5170 MHz to 5330 MHz frequency domain / range may be divided into one channel via a 160 MHz frequency domain.

[0222] Fig.17 Illustrate examples of channels used / supported / defined in the 6 GHz band.

[0223] 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.

[0224] 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.

[0225] 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.

[0226] 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.

[0227] Hereinafter, a PPDU transmitted / received in a STA of the present specification will be described.

[0228] Fig.18 An example of PPDU used in this specification is described.

[0229] Fig.18The PPDU of the WLAN may be referred to by various terms such as EHT PPDU, TX PPDU, RX PPDU, first type or Nth type PPDU, etc. For example, in the present specification, PPDU or EHT PPDU may be referred to by various terms such as TX PPDU, RX PPDU, first type or Nth type PPDU, etc. In addition, the EHT PPDU may be used in the EHT system and / or a new WLAN system enhanced from the EHT system.

[0230] Fig.18 The PPDU may indicate all or part of the PPDU type used in the EHT system. For example, Fig.18 The example of can be used for both single user (SU) mode and multi-user (MU) mode. In other words, Fig.18 The PPDU may be a PPDU for one receiving STA or multiple receiving STAs. Fig.18 When the PPDU is used in trigger-based (TB) mode, it can be omitted Fig.18 In other words, a STA that has received a trigger frame for uplink MU (UL-MU) may send an EHT-SIG in Fig.18 The PPDU of EHT-SIG is omitted in the example.

[0231] exist Fig.18 In the physical layer, L-STF to EHT-LTF may be referred to as a preamble or a physical preamble and may be generated / sent / received / obtained / decoded in a physical layer.

[0232] You can Fig.18 The subcarrier spacing of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG and EHT-SIG fields is determined to be 312.5kHz, and the subcarrier spacing of the EHT-STF, EHT-LTF and data fields can be determined to be 78.125kHz. That is, the tone index (or subcarrier index) of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, EHT-SIG fields can be expressed in units of 312.5kHz, and the tone index (or subcarrier index) of the EHT-STF, EHT-LTF and data fields can be expressed in units of 78.125kHz.

[0233] exist Fig.18 In the PPDU, the L-LTF and L-STF can be the same as those in the regular fields.

[0234] 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 an HE PPDU, the length field may be determined as "a multiple of 3" + 1 or "a multiple of 3" + 2. In other words, for non-HT, HT, VHT PPDU, or EHT PPDU, the value of the length field may be determined as a multiple of 3, and for HE PPDU, the value of the length field may be determined as "a multiple of 3" + 1 or "a multiple of 3" + 2.

[0235] For example, the transmitting STA may apply BCC encoding based on 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-bit coded bits, thereby generating 48 BPSK symbols. The transmitting STA may map the 48 BPSK symbols to positions other than the pilot subcarriers {subcarrier indexes -21, -7, +7, +21} and the DC subcarrier {subcarrier index 0}. As a result, the 48 BPSK symbols may be mapped to subcarrier indexes -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 the subcarrier index {-28, -27, +27, +28}. The aforementioned signal may be used for channel estimation in the frequency domain corresponding to {-28, -27, +27, +28}.

[0236] The transmitting STA may generate the RL-SIG 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 whether the RX PPDU is a HE PPDU or an EHT PPDU.

[0237] The Universal SIG (U-SIG) can be inserted in Fig.18 The U-SIG can be referred to by various terms such as a first SIG field, a first SIG, a first type SIG, a control signal, a control signal field, a first (type) control signal, etc.

[0238] The U-SIG may include N bits of information 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) used for the U-SIG may have a duration of 4 μs. Each symbol of the U-SIG may be used to send 26 bits of information. For example, each symbol of the U-SIG may be sent / received based on 52 data tones and 4 pilot tones.

[0239] Through U-SIG (or U-SIG field), for example, A-bit information (e.g., 52 uncoded bits) can be transmitted. The first symbol of U-SIG can transmit the first X bits of information of A-bit information (e.g., 26 uncoded bits), and the second symbol of U-SIG can transmit the remaining Y bits of information of A-bit information (e.g., 26 uncoded bits). For example, the transmitting STA can obtain 26 uncoded bits included in each U-SIG symbol. The transmitting STA can perform convolutional coding (i.e., BCC coding) based on a rate of R=1 / 2 to generate 52 coded bits, and can perform interleaving on the 52 coded bits. The transmitting STA can perform BPSK modulation on the interleaved 52 coded bits to generate 52 BPSK symbols to be assigned to each U-SIG symbol. In addition to DC index 0, one U-SIG symbol can be sent 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) excluding the pilot tones, namely, tones -21, -7, +7, +21.

[0240] For example, the A-bit information (e.g., 52 uncoded 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 of the first symbol allocated to the U-SIG and the remaining 16 bits in the second symbol excluding the CRC / tail field, and may be generated based on a conventional CRC calculation algorithm. In addition, the tail field may be used to terminate the trellis of the convolutional decoder and may be set to, for example, "000000".

[0241] The A-bit information (e.g., 52 uncoded bits) transmitted by the U-SIG (or U-SIG field) may be divided into version-independent bits and version-dependent bits. For example, the version-independent bits may have a fixed or variable size. For example, the version-independent bits may be assigned only to the first symbol of the U-SIG, or the version-independent bits may 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 may be referred to by various terms such as a first control bit, a second control bit, etc.

[0242] For example, the version-independent bits of the U-SIG may include a 3-bit PHY version identifier. For example, the 3-bit PHY version identifier may include information related to the PHY version of the TX / RX PPDU. For example, the first value of the 3-bit PHY version identifier may indicate that the TX / RX PPDU is an EHT PPDU. In other words, when the transmitting STA transmits an EHT PPDU, the 3-bit PHY version identifier may be set to a first value. In other words, the receiving STA may determine that the RX PPDU is an EHT PPDU based on the PHY version identifier having a first value.

[0243] For example, the version-independent bits of the U-SIG may include a 1-bit UL / DL Flag field. A first value of the 1-bit UL / DL Flag field is associated with UL communication, and a second value of the UL / DL Flag field is associated with DL communication.

[0244] For example, the version-independent bits of the U-SIG may include information related to the TXOP length and information related to the BSS color ID.

[0245] For example, when the EHT PPDU is divided into various types (for example, various types such as EHT PPDU related to SU mode, EHT PPDU related to MU mode, EHT PPDU related to TB mode, EHT PPDU related to extended range transmission, etc.), information related to the type of the EHT PPDU can be included in the version-related bit of the U-SIG.

[0246] For example, the U-SIG may include: 1) a bandwidth field including information related to the 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 a dual subcarrier modulation (DCM) scheme is applied to the EHT-SIG; 4) a field including information related to the number of symbols used 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 EHT-LTF / STF; and 7) information related to a field indicating the EHT-LTF length and the CP length.

[0247] Can Fig.18 Preamble puncturing is applied to the PPDU of the primary 20 MHz band. Preamble puncturing implies that puncturing is applied to part of the full band (e.g., the secondary 20 MHz band). For example, when sending an 80 MHz PPDU, the STA may apply puncturing to the secondary 20 MHz band in the 80 MHz band, and may send the PPDU only through the primary 20 MHz band and the secondary 40 MHz band.

[0248] For example, the pattern of the leading perforation can be preconfigured. For example, when the first perforation pattern is applied, perforation can be applied only to the auxiliary 20 MHz band in the 80 MHz band. For example, when the second perforation pattern is applied, perforation can be applied only to any one of the two auxiliary 20 MHz bands in the auxiliary 40 MHz band included in the 80 MHz band. For example, when the third perforation pattern is applied, perforation can be applied only to the auxiliary 20 MHz band in the main 80 MHz band included in the 160 MHz band (or the 80+80 MHz band). For example, when the fourth perforation pattern is applied, perforation can be applied to at least one 20 MHz channel that does not belong to the main 40 MHz band in the presence of the main 40 MHz band in the 80 MHz band included in the 160 MHz band (or the 80+80 MHz band).

[0249] 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 continuous bandwidth, and the second field of the U-SIG may include information related to the preamble puncturing applied to the PPDU.

[0250] For example, based on the following method, the U-SIG and the EHT-SIG may include information related to the preamble puncturing. When the bandwidth of the PPDU exceeds 80 MHz, the U-SIG can be configured separately in units of 80 MHz. For example, when the bandwidth of the PPDU is 160 MHz, the PPDU may include a first U-SIG for a first 80 MHz band and a second U-SIG for a second 80 MHz band. In this case, the first field of the first U-SIG may include information related to the 160 MHz bandwidth, and the second field of the first U-SIG may include information related to the preamble puncturing applied to the first 80 MHz band (i.e., information related to the preamble puncturing pattern). In addition, the first field of the second U-SIG may include information related to the 160 MHz bandwidth, and the second field of the second U-SIG may 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 continuous with the first U-SIG may include information related to preamble puncturing applied to the second 80 MHz band (i.e., information related to the preamble puncturing pattern), and the EHT-SIG continuous with the second U-SIG may include information related to preamble puncturing applied to the first 80 MHz band (i.e., information related to the preamble puncturing pattern).

[0251] Additionally or alternatively, based on the following method, the U-SIG and the EHT-SIG may include information related to preamble puncturing. The U-SIG may include information related to preamble puncturing for all frequency bands (ie, 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 may include information related to preamble puncturing (ie, information related to the preamble puncturing pattern).

[0252] 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 duplicated. That is, four identical U-SIGs can be included in the 80 MHz PPDU. PPDUs with bandwidths exceeding 80 MHz can include different U-SIGs.

[0253] Fig.18 The EHT-SIG in the U-SIG may include control information for receiving STAs. The EHT-SIG may be transmitted through at least one symbol, and one symbol may have a length of 4 μs. Information related to the number of symbols for the EHT-SIG may be included in the U-SIG.

[0254] The EHT-SIG may include reference Figure 8 and Fig. 9For example, the EHT-SIG may include the following: Figure 8 The common field of EHT-SIG may be omitted, and the number of user-specific fields may be determined based on the number of users.

[0255] As in Figure 8 In the example of , the common field of EHT-SIG and the user-specific field of EHT-SIG may be encoded separately. One user block field included in the user-specific field may include information for two users, but the last user block field included in the user-specific field may include information for one user. That is, one user block field of EHT-SIG may include a maximum of two user fields. Fig. 9 In the example of , each user field may be associated with a MU-MIMO allocation or may be associated with a non-MU-MIMO allocation.

[0256] As in Figure 8 In the example of , the common field of the EHT-SIG may include a CRC bit and a tail bit. The length of the CRC bit may be determined to be 4 bits. The length of the tail bit may be determined to be 6 bits and may be set to "000000".

[0257] As in Figure 8 In the example of , the common field of EHT-SIG may include RU allocation information. The RU allocation information may imply information related to the location of the RU to which multiple users (ie, 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.

[0258] The examples of Tables 5 to 7 are examples of 8-bit (or N-bit) information for various RU allocations. The index shown in each table may be modified, and some entries in Tables 5 to 7 may be omitted, and entries may be added (not shown).

[0259] The examples of Tables 5 to 7 relate to information related to the location of RUs allocated to the 20 MHz band. For example, "index 0" of Table 5 may be in the case where nine 26-RUs are allocated separately (e.g., Figure 5 Nine 26-RU cases shown in the figure) were used.

[0260] In addition, multiple RUs may be allocated to one STA in the EHT system. For example, with respect to "index 60" of Table 6, one 26-RU may be allocated to the leftmost user (ie, receiving STA) of the 20 MHz band, one 26-RU and one 52-RU may be allocated to the right side thereof, and five 26-RUs may be allocated to the right side thereof separately.

[0261] [Table 5]

[0262]

[0263] [Table 6]

[0264]

[0265] [Table 7]

[0266]

[0267] A mode in which the common field of the EHT-SIG is omitted may be supported. The mode in which the common field of the EHT-SIG is omitted may be referred to as a compressed mode. When the compressed mode is used, multiple users (ie, multiple receiving STAs) may decode the PPDU (eg, the data field of the PPDU) based on non-OFDMA. That is, multiple users of the EHT PPDU may decode the PPDU (eg, the data field of the PPDU) received via the same frequency band. In addition, when the non-compressed mode is used, multiple users of the EHT PPDU may decode the PPDU (eg, the data field of the PPDU) based on OFDMA. That is, multiple users of the EHT PPDU may receive the PPDU (eg, the data field of the PPDU) via different frequency bands.

[0268] The EHT-SIG may be configured based on various MCS schemes. As described above, information related to the MCS scheme applied to the EHT-SIG may be included in the U-SIG. The EHT-SIG may be configured based on the DCM scheme. For example, among the N data tones (e.g., 52 data tones) allocated to the EHT-SIG, a first modulation scheme may be applied to half of the continuous tones, and a second modulation scheme may be applied to the remaining half of the continuous tones. That is, the transmitting STA may use a first modulation scheme to modulate specific control information by a first symbol and assign it to half of the continuous tones, and may use a second modulation scheme to modulate the same control information by using a second symbol and assign it to the remaining half of the continuous tones. As described above, information (e.g., a 1-bit field) regarding whether the DCM scheme is applied to the EHT-SIG may be included in the U-SIG.

[0269] 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 channels in a MIMO environment or an OFDMA environment.

[0270] Can be set according to various types Fig.18 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 may have a period of 0.8 μs, and the periodic signal of 0.8 μs may 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) may 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 may have a period of 1.6 μs, and the periodic signal of 1.6 μs may be repeated 5 times to become a second type of STF with a length of 8 μs. In the following, an example of a sequence for configuring the EHT-STF (i.e., an EHT-STF sequence) is proposed. The following sequence can be modified in various ways.

[0271] The EHT-STF may be configured based on the following sequence M.

[0272] <Formula 1>

[0273] M={–1,–1,–1,1,1,1,–1,1,1,1,–1,1,1,–1,1}

[0274] The EHT-STF for a 20MHz PPDU may be configured based on the following formula. The following example may be a first type (ie, 1x STF) sequence. For example, a first type sequence may be included in an EHT-PPDU that is not a triggered (TB) PPDU. In the following formula, (a:b:c) may imply a duration of b tone intervals (ie, subcarrier intervals) defined from tone index (ie, subcarrier index) 'a' to tone index 'c'. For example, the following formula 2 may represent a sequence of 16 tone intervals defined from tone index -112 to tone index 112. Since a subcarrier spacing of 78.125kHz is applied to EHT-STR, 16 tone intervals may imply that the EHT-STF coefficients (or elements) are arranged at intervals of 78.125*16=1250kHz. In addition, * implies multiplication, and sqrt() implies square root. In addition, j implies an imaginary number.

[0275] <Formula 2>

[0276] EHT-STF(-112:16:112)={M}*(1+j) / sqrt(2)

[0277] EHT-STF(0)=0

[0278] The EHT-STF for a 40 MHz PPDU may be configured based on the following equation: The following example may be a first type (ie, 1x STF) sequence.

[0279] <Formula 3>

[0280] EHT-STF(-240:16:240)={M,0,-M}*(1+j) / sqrt(2)

[0281] The EHT-STF for 80 MHz PPDU may be configured based on the following equation: The following example may be a first type (ie, 1x STF) sequence.

[0282] <Formula 4>

[0283] EHT-STF(-496:16:496)={M,1,–M,0,–M,1,–M}*(1+j) / sqrt(2)

[0284] The EHT-STF for 160 MHz PPDU may be configured based on the following equation: The following example may be a first type (ie, 1x STF) sequence.

[0285] <Formula 5>

[0286] EHT-STF(-1008:16:1008)={M,1,–M,0,–M,1,–M,0,–M,–1,M,0,–M,1,–M}*(1+j) / sqrt(2)

[0287] In the EHT-STF for 80+80 MHz PPDU, the sequence for the lower 80 MHz may be the same as Equation 4. In the EHT-STF for 80+80 MHz PPDU, the sequence for the upper 80 MHz may be configured based on the following equation.

[0288] <Formula 6>

[0289] EHT-STF(-496:16:496)={-M,-1,M,0,–M,1,–M}*(1+j) / sqrt(2)

[0290] The following Equations 7 to 11 are related to an example of a second type (ie, 2x STF) sequence.

[0291] <Formula 7>

[0292] EHT-STF(-120:8:120)={M,0,-M}*(1+j) / sqrt(2)

[0293] The EHT-STF for 40 MHz PPDU may be configured based on the following equation.

[0294] <Formula 8>

[0295] EHT-STF(-248:8:248)={M,–1,–M,0,M,–1,M}*(1+j) / sqrt(2)

[0296] EHT-STF(-248)=0

[0297] EHT-STF(248)=0

[0298] The EHT-STF for 80 MHz PPDU may be configured based on the following equation.

[0299] <Formula 9>

[0300] EHT-STF(-504:8:504)={M,–1,M,–1,–M,–1,M,0,–M,1,M,1,–M,1,–M}*(1+j) / sqrt(2)

[0301] The EHT-STF for 160 MHz PPDU may be configured based on the following formula.

[0302] <Formula 10>

[0303] 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)

[0304] EHT-STF(-8)=0,EHT-STF(8)=0,

[0305] EHT-STF(-1016)=0,EHT-STF(1016)=0

[0306] In the EHT-STF for 80+80 MHz PPDU, the sequence for the lower 80 MHz may be the same as Equation 9. In the EHT-STF for 80+80 MHz PPDU, the sequence for the upper 80 MHz may be configured based on the following equation.

[0307] <Formula 11>

[0308] EHT-STF(-504:8:504)={–M,1,–M,1,M,1,–M,0,–M,1,M,1,–M,1,–M}*(1+j) / sqrt(2)

[0309] EHT-STF(-504)=0,

[0310] EHT-STF(504)=0

[0311] The EHT-LTF may have first, second, and third types (i.e., 1x, 2x, 4x LTF). For example, the first / second / third type LTF may 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 may have a time length of 3.2 / 6.4 / 12.8 μs. In addition, GIs of various lengths (e.g., 0.8 / 1 / 6 / 3.2 μs) may be applied to the first / second / third type LTF.

[0312] Information related to the type of STF and / or LTF (including information related to the GI applied to the LTF) may be included in Fig.18 SIG-A field and / or SIG-B field, etc.

[0313] Can be based on Figure 5 and Figure 6 Example to configure Fig.18 PPDU (e.g., EHT-PPDU).

[0314] For example, based on Figure 5 The RU is used to configure the EHT PPDU sent on the 20MHz band, that is, the 20MHz EHT PPDU. Figure 5 The positions of RUs that determine the EHT-STF, EHT-LTF, and data fields included in the EHT PPDU are shown in FIG.

[0315] Can be based on Figure 6 The RU of the 40MHz band is configured to send an EHT PPDU, i.e., a 40MHz EHT PPDU. Figure 6 The positions of RUs that determine the EHT-STF, EHT-LTF, and data fields included in the EHT PPDU are shown in FIG.

[0316] because Figure 6 The RU position corresponds to 40MHz, so it can be Figure 6 The tone plan for 80 MHz is determined when the pattern of is repeated twice. That is, the tone plan for 80 MHz can be determined based on Figure 7 The RU is Figure 6 The RU repeats the new tone schedule twice to send the 80 MHz EHTP PDU.

[0317] when Figure 6 When the pattern is repeated twice, 23 tones (i.e., 11 guard tones + 12 guard tones) can be configured in the DC region. That is, the tone plan for the 80 MHz EHT PPDU allocated based on OFDMA can have 23 DC tones. Different from this, the 80 MHz EHT PPDU allocated based on non-OFDMA (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.

[0318] Can Figure 6 The pattern is repeated several times in such a way that the tone plan for 160 / 240 / 320MHz is configured.

[0319] Based on the following method Fig.18 The PPDU is determined (or identified) as an EHT PPDU.

[0320] The receiving STA may 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 it is detected that the result of applying "modulo 3" to the value of the length field of the L-SIG of the RX PPDU is "0", the RX PPDU may be determined as an EHT PPDU. When the RX PPDU is determined to be an EHT PPDU, the receiving STA may determine the type of the RX PPDU as an EHT PPDU based on Fig.18 The type of the EHT PPDU (e.g., SU / MU / triggered / extended range type) can be detected by using bit information included in the symbol after the RL-SIG of the RX PPDU. In other words, the receiving STA can determine that the RX PPDU is 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 continuous with the L-SIG field and is the same as the L-SIG; 3) the L-SIG including the length field, in which the result of applying "modulo 3" is set to "0"; and 4) the 3-bit PHY version identifier of the aforementioned U-SIG (e.g., a PHY version identifier having a first value).

[0321] For example, the receiving STA may 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 is a BPSK symbol; 2) when an RL-SIG in which the L-SIG is repeated is detected; and 3) when it is detected that the result of applying "modulo 3" to the value of the length field of the L-SIG is "1" or "2", the RX PPDU may be determined as a HEPPDU.

[0322] For example, the receiving STA may determine the type of the RX PPDU as 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 the RL-SIG in which the L-SIG is repeated is not detected, the RX PPDU may be determined as non-HT, HT, and VHT PPDU. In addition, even if the receiving STA detects RL-SIG repetition, when it is detected that the result of applying "modulo 3" to the length value of the L-SIG is "0", the RX PPDU may be determined as non-HT, HT, and VHT PPDU.

[0323] 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 based on Fig.18 PPDU transmission / reception signal. Fig.18 The PPDU can be used to send / receive various types of frames. For example, Fig.18 The PPDU 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) notification, and trigger frames. For example, Fig.18 The PPDU may be used for management frames. Examples of management frames may include beacon frames, (re)association request frames, (re)association response frames, probe request frames, and probe response frames. For example, Fig.18 The PPDU can be used for data frames. For example, Fig.18 The PPDU may be used to simultaneously transmit at least two or more of a control frame, a management frame, and a data frame.

[0324] Fig.19 An example of a modified transmitting device and / or receiving device of the present specification is described.

[0325] Figure 1 Each device / STA of sub-graph (a) / (b) can be modified as follows Fig.19 shown. Fig.19 The transceiver 630 can be used with Figure 1 The transceivers 113 and 123 are the same. Fig.19 The transceiver 630 may include a receiver and a transmitter.

[0326] Fig.19 The processor 610 can be used with Figure 1 The processors 111 and 121 are the same. Alternatively, Fig.19 The processor 610 can be used with Figure 1 The processing chips 114 and 124 are the same.

[0327] Fig.19 The memory 620 can be connected with Figure 1 The memories 112 and 122 are the same. Alternatively, Fig.19 The memory 620 may be Figure 1 The memories 112 and 122 are different separate external memories.

[0328] Reference 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 input to be used by the processor 610. The keypad 614 may be displayed on the display 613. The SIM card 615 may be an integrated circuit for securely storing an International Mobile Subscriber Identity (IMSI) and its associated keys, which are used to identify and authenticate users on mobile telephony devices such as mobile phones and computers.

[0329] Reference Fig.19 The speaker 640 may output a result related to the sound processed by the processor 610. The microphone 641 may receive an input related to the sound to be used by the processor 610.

[0330] Fig. 20 An example of HE-PPDU is shown.

[0331] The illustrated L-STF 2000 may include a short training Orthogonal Frequency Division Multiplexing symbol (OFDM). The L-STF 2000 may be used for frame detection, automatic gain control (AGC), diversity detection, and coarse frequency / time synchronization.

[0332] The L-LTF 2010 may include a long training Orthogonal Frequency Division Multiplexing (OFDM) symbol. The L-LTF 2010 may be used for fine frequency / time synchronization and channel estimation.

[0333] L-SIG 2020 may be used to transmit control information. L-SIG 2020 may include information related to data transmission rate and data length. In addition, L-SIG 2020 may be transmitted repeatedly. That is, L-SIG 2020 may be configured in a repeated format (e.g., may be referred to as R-LSIG).

[0334] HE-SIG-A 2030 may include control information common to receiving stations.

[0335] Specifically, HE-SIG-A 2030 may include information related to the following: 1) DL / UL indicator; 2) BSS color field as an identifier of the BSS; 3) a field indicating the remaining time of the current TXOP duration / cycle; 4) a bandwidth field indicating whether it is 20, 40, 80, 160 or 80+80 MHz; 5) a field indicating the MCS scheme applied to HE-SIG-B; 6) an indication field indicating whether dual subcarrier modulation (DCM) is applied to the HE-SIG-B of the MCS; 7) a field indicating the number of symbols used for HE-SIG-B; 8) a field indicating whether HE-SIG-B is generated on the full / entire frequency band; 9) a field indicating the number of symbols of HE-LTF; 10) a field indicating the length of HE-LTF and the CP length; 11) a field indicating whether there are additional OFDM symbols for LDPC coding; 12) a field indicating control information about packet extension (PE); and / or 13) a field indicating information related to the CRC field of HE-SIG-A, etc. At least one field of the HE-SIG-A may be omitted or changed. In addition, in other environments where the HE-SIG-A is not a multi-user (MU) environment, some fields may be added or omitted.

[0336] In addition, HE-SIG-A 2030 may consist of two parts: HE-SIG-A1 and HE-SIG-A2. HE-SIG-A1 and HE-SIG-A2 included in HE-SIG-A may be defined in the following format structure (field) according to the corresponding PPDU. First, the HE-SIG-A field of HE SUPPDU may be defined as follows.

[0337] [Table 8]

[0338]

[0339] [Table 9]

[0340]

[0341] [Table 10]

[0342]

[0343] [Table 11]

[0344]

[0345] In addition, the HE-SIG-A field of the HE MU PPDU may be defined as follows.

[0346] [Table 12]

[0347]

[0348] [Table 13]

[0349]

[0350] [Table 14]

[0351]

[0352] [Table 15]

[0353]

[0354] In addition, the HE-SIG-A field of the HE TB PPDU can be defined as follows.

[0355] [Table 16]

[0356]

[0357] [Table 17]

[0358]

[0359] [Table 18]

[0360]

[0361] [Table 19]

[0362]

[0363] [Table 20]

[0364]

[0365] As described above, HE-SIG-B 2040 may be included only for a multi-user (MU) PPDU. Basically, HE-SIG-A 2050 or HE-SIG-B 2060 may include resource allocation information (or virtual resource allocation information) for at least one receiving STA.

[0366] Hereinafter, technical features of channel bundling supported by STA of the present disclosure will be described.

[0367] For example, in the IEEE 802.11n system, 40 MHz channel bonding can be performed by combining two 20 MHz channels. In addition, 40 / 80 / 160 MHz channel bonding can be performed in the IEEE 802.11ac system.

[0368] For example, a STA may perform channel bundling on a primary 20 MHz channel (P20 channel) and a secondary 20 MHz channel (S20 channel). A backoff count / counter may be used in the channel bundling process. The backoff count value may be selected as a random value and decremented during the backoff interval. Typically, when the backoff count value becomes 0, the STA may attempt to access the channel.

[0369] 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 that performs channel bundling determines whether the S20 channel remains in an idle state within a certain period of time (e.g., point coordination function interframe space (PIFS)). If the S20 channel is in an idle state, the STA can perform bundling on the P20 channel and the S20 channel. That is, the STA can send a signal (PPDU) through a 40MHz channel (i.e., a 40MHz bundling channel) including the P20 channel and the S20 channel.

[0370] Fig.21 An example of channel bonding is shown. Fig.21 As shown in , the primary 20 MHz channel and the secondary 20 MHz channel are configured to form 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.

[0371] When the channel adjacent to the main channel is in an idle state, channel bundling can be performed. That is, the main 20MHz channel, the auxiliary 20MHz channel, the auxiliary 40MHz channel, and the auxiliary 80MHz channel can be bundled sequentially. However, when it is determined that the auxiliary 20MHz channel is in a busy state, channel bundling cannot be performed even if all other auxiliary channels are in an idle state. In addition, when it is determined that the auxiliary 20MHz channel is in an idle state and the auxiliary 40MHz channel is in a busy state, channel bundling can be performed only on the main 20MHz channel and the auxiliary 20MHz channel.

[0372] Hereinafter, preamble puncturing supported by a station (STA) of this specification will be described.

[0373] For example, in Fig.21In the example of , when the primary 20MHz channel, the secondary 40MHz channel, and the secondary 80MHz channel are all in an idle state, and the secondary 20MHz channel is in a busy state, bundling between the secondary 40MHz channel and the secondary 80MHz channel may not be possible. In this case, the STA can configure a 160MHz 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.) sent through the secondary 20MHz channel (or perform preamble puncturing on the preamble), so that the signal can be sent through the channel in an idle state. In other words, the STA can perform preamble puncturing on part of the frequency band of the PPDU. Information about preamble puncturing (e.g., information about the 20 / 40 / 80MHz channel / frequency band to which puncturing is applied) may be included in the signal field (e.g., HE-SIG-A, U-SIG, EHT-SIG) of the PPDU.

[0374] Hereinafter, technical features of multi-link (ML) supported by STA of the present disclosure will be described.

[0375] The STA (AP and / or non-AP STA) of the present disclosure may support multi-link (ML) communication. ML communication may refer to communication supporting multiple links. Links related to ML communication may include Fig.15 The 2.4 GHz frequency band shown in Fig.16 The 5 GHz band shown in Fig.17 The channels of the 6 GHz frequency band shown in (e.g., 20 / 40 / 80 / 160 / 240 / 320 MHz channels).

[0376] Multiple links for ML communication may be set in various ways. For example, multiple links for ML communication supported by one STA may be multiple channels in the 2.4 GHz band, multiple channels in the 5 GHz band, and multiple channels in the 6 GHz band. Alternatively, multiple links for ML communication supported by one STA may be a combination of at least one channel in the 2.4 GHz band (or the 5 GHz / 6 GHz band) and at least one channel in the 5 GHz band (or the 2.4 GHz / 6 GHz band). At the same time, at least one of the multiple links for ML communication supported by one STA may be a channel to which preamble puncturing is applied.

[0377] The STA may perform ML establishment to perform ML communication. The ML establishment may be performed based on a management frame or a control frame such as a beacon, a probe request / response, an association request / response, etc. For example, information about the ML establishment may be included in an element field included in a beacon, a probe request / response, an association request / response, etc.

[0378] When the ML establishment is completed, an enabled link for ML communication may be determined. The STA may perform frame exchange through at least one of the multiple links determined as enabled links. For example, the enabled link may be used for at least one management frame, control frame, and data frame.

[0379] When a STA supports multiple links, the transceiver supporting each link can operate as a logical STA. For example, a STA supporting two links can be expressed as a multi-link device (MLD), which includes a first STA for a first link and a second STA for a second link. For example, an AP supporting two links can be expressed as an APMLD, which includes a first AP for the first link and a second AP for the second link. In addition, 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.

[0380] In the following, more specific features related to ML establishment will be described.

[0381] MLD (AP MLD and / or non-AP MLD) can send information about the link 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 may include at least one of the following: 1) information about whether the MLD (or STA) supports simultaneous RX / TX operation, 2) information about the number / upper limit of uplinks / downlinks 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 type (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 service identifier (TID) available or preferred in at least one uplink / downlink. The TID is related to the priority of the service data and is expressed as eight types of values ​​according to the conventional wireless LAN standard. That is, eight TID values ​​corresponding to four access categories (ACs) (AC_BK (background), AC_BE (best effort), AC_VI (video), AC_VO (voice)) according to the conventional WLAN standard may be defined.

[0382] For example, all TIDs may be preconfigured 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 TID is negotiated through additional ML settings, the negotiated TID may be used for ML communication.

[0383] Multiple links available to the sending MLD and receiving MLD related to ML communication can be configured through ML establishment, and this can be called "enabled links". "Enabled links" can be called differently with various expressions. For example, it can be called various expressions such as first link, second link, transmission link and reception link.

[0384] After the ML establishment is completed, the MLD may update the ML establishment. For example, when it is necessary to update the information about the link, the MLD may send information about the new link. The information about the new link may be sent based on at least one of a management frame, a control frame, and a data frame.

[0385] According to an embodiment, the MLD may include a non-AP MLD and an AP-MLD. The non-AP MLD and the AP-MLD may be classified according to the function of an access point (AP). The non-AP MLD and the AP-MLD may be physically separated or logically separated. For example, when the MLD performs an AP function, it may be referred to as an AP MLD, and when the MLD performs an STA function, it may be referred to as a non-AP MLD.

[0386] Hereinafter, in this specification, an MLD has one or more STAs connected thereto and one MAC Service Access Point (SAP) connected to a Logical Link Control (LLC). MLD may refer to a physical device or to a logical device. Hereinafter, the term device may refer to an MLD.

[0387] In addition, the MLD may include at least one STA connected to each link in the multi-link. For example, the processor of the MLD may control the at least one STA. For example, the at least one STA may be independently configured and may operate independently. The at least one STA may each include a processor and a transceiver. For example, regardless of the processor of the MLD, the at least one STA may operate independently.

[0388] In the following, in order to simplify the description, the MLD (or the processor of the MLD) will be described in the present disclosure as controlling 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 send and / or receive signals.

[0389] 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, a non-AP MLD may support multiple links. A non-AP MLD may include multiple STAs. Multiple STAs may have one link per STA.

[0390] The EHT specification (802.11be specification) considers a multi-link device (MLD) structure in which one AP / non-AP MLD supports multiple links as the main technology. STAs included in non-AP MLDs can transmit (or transfer) information about other STAs in non-AP MLDs together through one link. Therefore, this has the effect of reducing the overhead of frame exchange. In addition, this also has the effect of increasing link usage efficiency and reducing STA power consumption.

[0391] Fig. 22 An exemplary structure of a non-AP MLD is shown.

[0392] Reference 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. Each of the multiple STAs may have one link. Although Fig. 22 An exemplary structure of a non-AP MLD is shown, but the structure of an AP MLD can also be the same as Fig. 22 The non-AP MLD structure shown is configured identically.

[0393] 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 frequency band. STA 2 may operate on link 2. Link 2 may be included in the 6 GHz frequency band. STA 3 may operate on link 3. Link 3 may be included in the 5 GHz frequency band. The frequency bands including links 1 / 2 / 3 are only exemplary, and thus, links may also be included in 2.4, 5, and 6 GHz.

[0394] As described above, in the case of AP / non-AP MLD supporting multiple links, each AP of AP MLD and each STA of non-AP MLD can be connected to each link through the link establishment process. And, according to the situation, through AP MLD or non-AP MLD, the link connected at this time can be switched or reconnected to another link.

[0395] In addition, in the EHT specification, in order to reduce power consumption, the link can be divided into an anchor link and a non-anchor link. An anchor link or a non-anchor link can be referred to as various terms. For example, an anchor link can be referred to as a primary link. And, a non-anchor link can be referred to as an auxiliary link.

[0396] According to an embodiment, an AP MLD supporting multiple links may manage links by designating each link as an anchor link or a non-anchor link. The AP MLD may support one or more links among the multiple links as anchor links. A non-AP MLD may use an anchor link by selecting one or more of its anchor links from an anchor link list (i.e., a list of anchor links supported by the AP MLD).

[0397] For example, the anchor link can be used not only for frame exchange for synchronization, but also for non-data frame exchange (ie, beacon and management frames). Alternatively, the non-anchor link can be used only for data frame exchange.

[0398] During the idle period, the non-AP MLD may perform monitoring only on the anchor link (or monitor only the anchor link) in order 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 in order to receive beacons and management frames. One or more anchor links should always maintain an enabled state. In contrast, the non-anchor link is only used for data frame exchange. Therefore, the STA corresponding to the non-anchor link (or the STA connected to the non-anchor link) can enter a doze mode during the idle period when the channel / link is not used. By doing so, this has the effect of reducing power consumption.

[0399] Hereinafter, a protocol may be proposed that enables an AP MLD or a non-AP MLD to dynamically recommend or request a link reconnection for efficient link connection according to the situation. In addition, hereafter, in the present specification, an anchor link reconnection protocol based on an anchor link may be additionally proposed, the anchor link being used not only as a general link but also for the purpose of power reduction.

[0400] Implementation of link switching and reconnection

[0401] According to an embodiment, each link between the AP MLD and the non-AP MLD may be determined during the association or (re)association process. The AP MLD and the non-AP MLD may perform frame exchange via the links connected at this time. The detailed embodiments of the AP MLD and the non-AP MLD connected by the link establishment process may refer to Fig.23 describe.

[0402] Fig.23 An exemplary connection between an AP MLD and a non-AP MLD through a link establishment process is shown.

[0403] Reference Fig.23, the AP MLD may include AP 1, AP 2, and AP 3. And, the non-AP MLD may include STA 1 and STA 2. AP 1 and STA 1 may be connected via link 1. And, AP 2 and STA 2 may be connected via link 2.

[0404] For example, AP 1 and STA 1 may be connected through link 1 through a first link establishment procedure. AP 2 and STA 2 may be connected through link 2 through a second link establishment procedure. As another example, AP MLD and non-AP MLD may be connected through a single link establishment procedure. In other words, AP MLD and non-AP MLD may be connected through link 1 and link 2 based on a single link establishment procedure.

[0405] As described above, each AP and STA can perform frame exchange through the link to which they are connected. In addition, information about other links related to other APs or information about other links related to other STAs can be sent and / or received through one link.

[0406] However, after performing the above-mentioned link establishment process, the AP MLD or the non-AP MLD may request link switching or reconnection for more efficient frame exchange (eg, load balancing or interference avoidance, etc.) according to the situation / environment.

[0407] You can refer to Fig.24 Embodiments related to link switching or reconnection are described.

[0408] Fig.24 An example is shown where a link is switched or reconnected.

[0409] Reference 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 having a relatively small data load. In this case, this has the effect of enabling the AP MLD and the non-AP MLD to perform efficient data exchange.

[0410] Fig.25 A detailed example showing a link being switched or reconnected.

[0411] Reference Fig.25 , AP 1 of AP MLD may be connected to STA 1 of non-AP MLD through link 1. AP 2 of AP MLD may be connected to STA 2 of non-AP MLD through link 2. Thereafter, STA 2 may try / request to connect to AP 3 through link switching or reconnection, and STA 2 may be connected to AP 3 through link 2 based on the link switching or reconnection.

[0412] According to an embodiment, the AP MLD and the non-AP MLD may transceive (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 may select a link that is more suitable (or sufficient) for sending and / or receiving a signal based on the various information per current link and the information related to the link state. For example, the various information per current link may include information about the data traffic load per link and information about the channel access capability between the links. For example, the link state may be configured to be disabled or enabled, etc.

[0413] Hereinafter, in this specification, a process in which the AP MLD / non-AP MLD negotiates with the non-AP MLD / AP MLD to request switching or reconnecting to a link other than the initially connected link to increase its performance may be referred to as "link switching negotiation". The term "link switching negotiation" may also be referred to as many other terms, and thus, the terminology may also be changed.

[0414] Hereinafter, the link switching or reconnection process may be described by being divided into a case where the AP MLD requests the process and a case where the non-AP MLD requests the process.

[0415] Implementation Method of AP MLD Requesting Link Switching or Reconnection

[0416] According to an embodiment, for efficient data transmission, the AP MLD may request link switching or reconnection to a non-AP MLD. For example, for load balancing, the AP MLD may request the STA to switch its link or reconnect to a more efficient link based on the data traffic of each AP.

[0417] For example, the AP MLD may calculate / verify / confirm (or finally determine) a link suitable for the STA of the non-AP MLD based on the data traffic load information of each AP and / or the channel access capability information between each link (e.g., information related to simultaneous TX / RX (STR) capability, etc.). Thereafter, the AP MLD may request the STA (or non-AP MLD) link switching or reconnection based on the data traffic load information of each AP and / or the channel access capability information between each link.

[0418] As described above, when requesting link switching, the AP MLD may 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 may include a beacon or a management frame, etc.

[0419] With respect to the above-mentioned embodiments, an element or field including link information about a link considered to be most suitable may be newly proposed. The newly proposed element or field may be defined as a "recommended link". The term "recommended link" is merely exemplary, and therefore, the detailed terminology of the element or field may be changed.

[0420] Recommended link (element / field) : This is an element or field that enables the AP MLD to recommend the link that is most suitable for the STA other than the AP MLD based on various information per link (e.g., per-link data load, etc.). For example, the recommended link (element / field) may be indicated as link ID information of the AP MLD or AP BSS information, etc. In other words, the recommended link (element / field) may include link ID information of the AP MLD or AP BSS information, etc.

[0421] According to an embodiment, the recommended link (element / field) may be optionally included in the link switching response and then may be sent. For example, the STA may 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 may also perform a connection request for 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 possesses).

[0422] The detailed signal exchange process between the AP MLD and the non-AP MLD according to the above embodiment can be referred to Fig.26 describe.

[0423] Fig.26 The operations of AP MLD and non-AP MLD for link switching or reconnection are shown.

[0424] Reference Fig.26 , when STA2 is connected to AP2 via link 2, a large amount of data traffic may be concentrated on AP2. In other words, when STA2 is connected to AP2 via link 2, a large amount of data traffic may appear in AP2.

[0425] The AP MLD (or AP 2) may request the non-AP MLD (or STA 2) to reconnect to the AP 3 with which a relatively small number of STAs are connected. In general, a message for requesting reconnection is sent to the STA (i.e., STA 2) that wants to reconnect. However, depending on the situation (e.g., channel situation or link status), the message may be sent to any STA (i.e., other STA). In other words, the STA to which the request message (e.g., link switching request frame) for requesting reconnection is sent may be changed.

[0426] For example, when the STA (i.e., STA 2) that has received the request message for requesting reconnection accepts the request, the STA may send a response message "Accept" (e.g., a link switching response frame). As another example, if the STA (i.e., STA 2) rejects (or refuses) the request, the STA may send a response message "Reject".

[0427] In the case of a response message, the STA that accepts the reconnection (ie, STA 2) generally sends the response message to the initial link (the connection link before reconnection). However, by using the characteristics of the multi-link, the response message can also be sent through any other link (ie, other STA).

[0428] If STA 2 accepts the link reconnection request, after sending the response message, STA 2 can disconnect its initial connection with AP 2 and can request link reconnection with AP 3. At this time, the reconnection request process can be performed the same as the existing link establishment process between MLDs. After completing the link establishment process between AP 3 and STA 2, STA 2 can perform frame exchange with AP 3 through link 2.

[0429] On the contrary, if STA 2 rejects the link reconnection request, STA 2 and AP 2 may continue to use their initially connected link (ie, link 2) as is.

[0430] According to an embodiment, when the AP requests a link switch to the STA, and when a suitable link is recommended, the STA may or may not switch the link to the recommended link. For example, in order to enable the AP to recommend a suitable link to the STA, the above-mentioned recommended link may be used.

[0431] 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 other link switches from the AP based on other information in addition to the information included in the request message.

[0432] Therefore, the AP needs to inform the STA to accept or not accept (or reject) the response message. To this end, the AP can send a confirmation message (eg, a link switching confirmation frame) corresponding to the STA's response message (eg, a link switching response frame) to the STA.

[0433] The detailed operations of AP MLD and non-AP MLD according to the above embodiment can be referred to. Fig. 27 to describe.

[0434] Fig. 27 The operations of AP MLD and non-AP MLD for link switching or reconnection are shown.

[0435] Reference Fig. 27 , AP 2 may request link switching, including recommended link information, from STA 2. In other words, AP 2 may send a link switching request frame including recommended link information to STA 2.

[0436] STA 2 may send acceptance or rejection of the link request through a link switch response frame.

[0437] For example, when link switching is accepted, STA 2 may include information about the link to be switched to the link switching response frame, and then may send the link switching response frame. At this time, the information about the link to be switched may be the same as or different from the recommended link.

[0438] As another example, when STA2 selects another link other than the recommended link provided by AP2 and responds to the request through a link switching response frame, AP may send a message corresponding to the final acceptance or non-acceptance response to STA. The corresponding message may be called a link switching confirmation frame.

[0439] For example, AP 2 may accept, through a link switching confirmation frame, the link switching to the link designated by STA 2. Based on the link switching confirmation frame, STA 2 may attempt to perform link switching to the link designated by it.

[0440] As another example, AP 2 may reject, through a link switch confirmation frame, the link switch to the link designated by STA 2. STA 2 and AP 2 may maintain their connection with their initial link without any link switch.

[0441] Fig. 27 The illustrated implementation can also be applied to a case where the AP has sent a link switching request frame without including recommended link information. For example, when an AP (e.g., AP 2) has sent a link switching request frame to a STA (e.g., STA 2) without including any recommended link information, the STA can respond to the AP with a link switching response frame after directly specifying the link to be switched based on information belonging to the STA (or owned by the STA). In this case, in addition, the AP should send a link switching confirmation frame corresponding to the final acceptance. Therefore, an implementation can be applied in which the AP sends a link switching confirmation frame even if the recommended link information is not included in the link switching request frame.

[0442] Implementation of non-AP MLD request link switching or reconnection

[0443] According to an embodiment, for efficient data transmission, the non-AP MLD may request link switching or reconnection to the APMLD. For example, in order to use the STR capability when performing data transmission, the non-AP MLD may request the AP MLD to switch or reconnect the connected link.

[0444] Fig.28 The operations of AP MLD and non-AP MLD for link switching or reconnection are shown.

[0445] Reference Fig.28 , AP MLD and non-AP MLD may perform link switching negotiation. STA 2 of non-AP MLD may send a link switching request frame to AP 2 of APMLD. As a response to the link switching request frame, AP 2 of AP MLD may send a link switching response frame to STA 2 of non-AP MLD. Although a link switching request frame or a link switching response frame may be sent and / or received through a link that is a switching target, the present disclosure shall not be limited thereto. A link switching request frame or a link switching response frame may be sent / received not only through a link that is a switching target, but may also be sent through various other links.

[0446] The non-AP MLD may request link switching or reconnection through various methods. Hereinafter, three different methods for the non-AP MLD to request link switching or reconnection may be proposed. More specifically, the three different methods may be described in the order of a request method, a non-request method, and a general method.

[0447] 1) Request method : This is a method in which a non-AP MLD requests various information of an AP included in the AP MLD to the AP MLD, and receives the various information accordingly. For example, the various information may include information on capabilities, operation elements, and BSS parameters.

[0448] According to an embodiment, the method by which the STA requests information of other APs connected to the AP MLD can be used not only in the case of reconfiguring the link, but also in various other cases. For example, after multi-link establishment, the STA can request BSS parameter information of other APs for link switching, and can select the best link based on the received information. Alternatively, during the discovery process, the STA can request BSS load information of each AP from the AP MLD, and can select a link through which to perform link establishment based on the received information. (However, hereinafter, it will be assumed that the number of APs of the AP MLD is greater than the number of STAs in the non-AP MLD.)

[0449] Therefore, the AP that has received the information request message may send any type of information from capability information, BSS parameter information, key parameters and / or operation element information of all APs in the AP MLD. The above example may be applied to all embodiments to be described below.

[0450] 2) Unsolicited Methods :This is a method in which the AP sends various information without any separate information request from a 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 in the case of reconfiguring the link but also in other various situations. Therefore, the AP that has received the information request message can send any type of information among capability information, BSS parameter information, key parameters and / or operation element information from all APs within the AP MLD. The above example can be applied to all embodiments to be described below.

[0451] 3) General approach : This is a method in which non-AP MLD requests link (re)selection based on various information obtained through a previous beacon frame without additional information.

[0452] 1) Request method

[0453] Hereinafter, implementation methods related to the above-mentioned request method may be described first.

[0454] According to an embodiment, the non-AP MLD may request the AP MLD for information for selecting a suitable link before link switching or reconnection. The STA may select a suitable link using per-AP data load information or per-link capability information (or other link information).

[0455] For example, the per-link capability information may be included in a beacon frame or the like and transmitted periodically.

[0456] As another information, as optional information, the per-link capability information may not be included in the beacon frame transmitted in each cycle period. Alternatively, in order to reduce frame overhead, the STA may receive only the information of the connected link or the information of 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 receive the per-link capability information for selecting a more suitable link.

[0457] In the above case, the non-AP MLD can request the latest information of the AP MLD's per-link capability information and per-link information (e.g., BSS parameter information or operation element information, etc.). The links of the per-link capability information and per-link information may include not only the links being sent and / or received, but also other links. For example, a field of a QoS data frame, a management frame, a probe response / request frame, a PS-poll frame, or an empty frame (the A-control field of the 11ax standard) can be used to request / send the latest information. Alternatively, a separate new frame may be defined to request / send the latest information.

[0458] According to an embodiment, in order to request the latest information of the per-link capability information and per-link information of the AP MLD, the STA may send a request message to the AP requesting the information required for link reselection. For example, the probe request frame defined in the prior art may be reused for the request message. As another example, a new frame for the request message may also be defined.

[0459] According to the implementation, the STA may specify the required specific information and may request the specified information from the AP. The specific information that can be specified may change 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 a response message. The detailed implementation related to the request and response of specific information may be described through the implementation related to the definition and operation of the IOM.

[0460] As another example, the STA may request all capability information (eg, including information of other links) currently carried by the AP MLD through a request message.

[0461] As shown in the above examples, the implementation of sending all information carried by the AP or only sending specific information specified by the STA can be defined / configured differently. For example, in order to specify (or send) only specific information, the AP can send all information or specify information based on a separate field or bitmap, etc.

[0462] In general, although the message requesting information to the AP MLD may be sent by a STA that wishes to reconnect, the message may be sent to any STA (ie, other STA) according to circumstances (channel circumstances or link status).

[0463] The AP MLD having received the request message may send a response message (i.e., an information message) including requested information necessary for link reselection (e.g., per-link data load information, STR capability information between links, etc.) to the non-AP MLD. For example, when a probe request frame of the prior art specification is reused for the request message, the AP (or AP MLD) should respond to the request message by using a probe response frame as a response message.

[0464] Although the response message may also be generally sent by the AP that has received the request message, the response message may also be sent to any AP (ie, other AP) by using the characteristics of the multi-link.

[0465] Optionally, the AP MLD may send a "recommended link" element for recommending a suitable link to the STA together with a response message including the above-mentioned various information (eg, the latest information required for link reselection).

[0466] The above request method can be used by the STA of non-AP MLD for link switching or reconnection. For example, when the STA of non-AP MLD wants to reselect a link due to link congestion, the STA of non-AP MLD can request BSS load information and BSS parameter information per link 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.

[0467] Hereinafter, in order to distinguish from a request message of link switching and a response message of link switching, the above request message and response message may be described as an information request message and an information response message.

[0468] The STA can reselect a suitable link based on the information included in the above information response message and request link switching or reconnection to the AP MLD through a link switching request message. The link switching request message can include information about the AP to be reconnected to the corresponding STA and link information.

[0469] When the AP MLD having received the request message accepts the request, the AP MLD may send a response message of “Accept.” And, when the AP MLD rejects (or refuses) the request, the AP MLD may send a response message of “Reject.”

[0470] When the request is accepted, the AP can perform link (re)establishment through a link-based frame exchange with the reselected AP starting from after the response message transmission. Conversely, when the request is rejected, the STA can continue to use the link of its initial connection as is.

[0471] For detailed examples of AP MLD and non-AP MLD operations according to the request method, refer to Fig.29 describe.

[0472] Fig.29 The operations of AP MLD and non-AP MLD for link switching or reconnection are shown.

[0473] Reference Fig.29 , when STA 2 of non-AP MLD wants to reselect the link to which it is connected, STA 2 may send an information request message to non-AP MLD through link 2. After receiving the information request message, AP MLD may send an information response message including information required for link reselection of non-AP MLD. STA 2 of non-AP MLD may send a request message for link switching (i.e., a link switching request frame) to AP 2 of AP MLD based on the information included in the above-mentioned information response message. Thereafter, STA 2 may receive a response message for link switching (i.e., a link switching request frame) and may perform link (re)establishment for link switching.

[0474] The embodiments related to the information request proposed in this specification can also be used / applied to the case where the STA requests necessary (or required) information from the AP. When the information included in the 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 but does not include information about other links, or when the AP only sends information related to the update or non-update of information of other links, the STA can request the insufficient (or missing) information from the AP.

[0475] For detailed examples of implementation, please refer to Fig.30 to describe.

[0476] Fig.30 The operation of requesting information about other APs on a non-AP MLD is shown.

[0477] Reference Fig.30 , AP MLD (or AP 1 to AP 3) can send only information related to the update or non-update of information of other APs (i.e., links) to STA through 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 related to other APs based on the information response message.

[0478] For example, other AP information (eg, BBS load, etc.) of AP MLD may not be included in the beacon, or AP 2 may only send information related to update or non-update (eg, version / update version) of other AP information.

[0479] STA 2 may need information of AP 1 (or information related to AP 1). STA 2 may request necessary information through AP 2. STA 2 may obtain information of AP 1 through a response message to the request. STA 2 may reselect a suitable link for link switching using the information of AP 1. For example, a frame for link switching may be configured differently.

[0480] In addition, even before the multi-link is established, the STA can use the above-mentioned request method to obtain the information of the AP carried by the AP MLD. During the multi-link establishment process of non-AP MLD and 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 which AP of the AP MLD the link should be established to. In this case, the STA of the non-AP MLD can request the AP for per-link specific information (for example, BSS load information of the AP carried by the AP MLD, etc.) in order to know the per-link status. For example, the STA can be a probe request as a request message. As another example, a new frame for the request message can be defined. The STA can include an indicator for requesting a specific element (for example, a request element or an extended request element or a PV1 probe response option element, etc.) and an indicator for indicating specific link information (for example, a link ID, etc.) in the request message, and then send the request message.

[0481] For example, a STA of a non-AP MLD may send a request message including 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 (BSS load information of all APs connected to the AP MLD of the corresponding AP) to the STA based on the STA's instruction by loading the information in a 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 BSS (i.e., AP) with the smallest 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.

[0482] Such a STA can use the above-mentioned request method as a method of obtaining per-AP information of the AP MLD in order to select a link to connect to before multi-link establishment.

[0483] Although the request method proposed in this specification can be used to obtain the information of other APs after multi-links are established, the request method can also be used to obtain the information of other APs even before multi-links are established.

[0484] Hereinafter, a new element / field including information for a STA of non-AP MLD to select a suitable link may be proposed.

[0485] For example, a "per link STA ratio" (element / field) may be proposed. The "per link STA ratio" may include information related to the ratio of the number of STAs connected per link. A detailed example of the "per link STA ratio" may be referred to Fig.31 describe.

[0486] Fig.31 A detailed example of the STA ratio per link is shown.

[0487] Reference Fig.31 , the STA ratio per link (element / field) may include information on the number of STAs or the STA ratio connected to each link in the entire AP MLD.

[0488] For example, when a total of 50 STAs are connected to the AP MLD having 3 links, 10 STAs may be connected to link 1 and 20 STAs may be connected to link 2. The AP MLD may transmit information about 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 (%).

[0489] For example, when information about STAs connected per link is expressed as a value, link 1 may be expressed / configured as 10, and link 2 may be expressed / configured as 20. Therefore, the value of the STA ratio per link 1 may be configured to be equal to 10. In addition, the value of the STA ratio per link 2 may be configured to be equal to 20.

[0490] As another example, when the information about the STAs connected per link is expressed as a ratio, link 1 may be expressed / configured as 20 (10 / 50)%, and link 2 may be expressed / configured as 40 (20 / 50)%. Therefore, the value of the STA ratio per link 1 may be configured to be equal to 20. In addition, the value of the STA ratio per link 2 may be configured to be equal to 40.

[0491] The above examples are merely exemplary, and the information about the STA connected per link may be configured differently. In addition to the above examples, the information about the STA connected per link may be configured to be equal to a relative value.

[0492] The STA can verify / obtain the number and ratio of connected STAs per link based on the above-mentioned information about the STAs connected per link, which can be used as information for link selection.

[0493] According to an embodiment, in addition to the above-mentioned "per link STA ratio" (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.

[0494] -BSS load information for each AP

[0495] - STR capability information between links

[0496] -TXOP information for each link

[0497] - NAV information for each link

[0498] - Recommended link information (i.e., "Recommended Link" element)

[0499] - STA ratio information per link connection (i.e., "STA ratio per link" element)

[0500] -other

[0501] In addition to the above-mentioned information / elements / fields, various information required for link selection may be included in the information response message and then may be transmitted.

[0502] The STA that has received the information (e.g., the information described in the above example) selects an AP to which the STA intends to switch or reconnect based on the received information, and then the STA may send a request message requesting to reconnect the link. When the AP MLD that has received the request message accepts the request, the AP MLD may send a response message "Accept". And, when the AP MLD rejects (or refuses) the request, the AP MLD may send a response message "Reject".

[0503] When the request is accepted, the AP can perform frame exchange through the link with the reselected AP from after the response message transmission. On the contrary, when the request is rejected, the STA can continue to use the link of its initial connection as it is.

[0504] 2) Non-request method

[0505] Unlike the request method in which the non-AP MLD directly requests additional information, according to the non-request method, the AP MLD can 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, an unsolicited 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 a frame for sending additional information to the non-AP MLD.

[0506] For example, when the beacon period is quite long, the mandatory information required for link switching of the non-AP MLD may be insufficient or may not be the latest information. Therefore, the AP may send a frame including the link capability information of the AP MLD to the non-AP MLD. Thereafter, the non-AP STA may obtain the latest information about the per-link capability of the AP MLD. The frame may be sent periodically or may be sent aperiodically.

[0507] For example, when periodically sending frames, the AP may send frames 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. In addition, when the FILS discovery frame is used as a frame, a frame may be sent every 20us. As another example, a cycle period negotiated through capability negotiation between the AP and the STA may also be used. For example, the transmission period may be indicated by the "periodicity" field and the "interval" field / subfield value of the IOM capability element.

[0508] As another example, when sending frames aperiodically, the AP may send frames each time an update event occurs in the AP's information (capabilities, BSS parameters, operating elements). As a detailed example, each time the AP's link capability changes, the changed information may be sent to the connected STA. In this case, the STA may maintain the latest information about the link capability.

[0509] According to the above example, since the non-AP STA does not send a separate request message for obtaining link capability, this can have the effect of generating relatively less frame exchange overhead compared to the request method. In addition, since the STA can receive updated information every time the main information is updated, this can have the effect of enabling the STA to usefully use the received information.

[0510] For detailed AP MLD and non-AP MLD operation examples according to the unsolicited method, please refer to Fig.32 describe.

[0511] Fig.32 The operations of AP MLD and non-AP MLD for link switching or reconnection are shown.

[0512] Reference Fig.32 , the AP MLD may send mandatory information required for link reselection to the non-AP MLD through a separate frame (eg, an information message) without any separate request message from the non-AP MLD.

[0513] According to an embodiment, Fig.32Unlike, the AP MLD can send information about the link capability to the STA through a field of a DL frame (e.g., a QoS data frame) sent by the AP MLD to the non-AP MLD without any separate request message from the non-AP MLD. The operation of the AP MLD and the non-AP MLD according to the embodiment can refer to Fig.33 describe.

[0514] Fig.33 The operations of AP MLD and non-AP MLD for link switching or reconnection are shown.

[0515] Reference Fig.33 , AP 2 may send information of another AP (or information related to another AP) to STA 2 based on a DL frame (i.e., DL 1). In other words, a DL frame may include information related to another AP. For example, information about another AP may be included in an A-Control field of the 802.11ax specification, etc. According to an embodiment, since an 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 key information of another AP, the update information may be sent through a separate message, such as Fig.32 As shown in the implementation example.

[0516] For example, key information of the AP may include A to Q as follows.

[0517] A. Includes channel switching notification elements

[0518] B. Includes extended channel switching announcement element

[0519] C. Modify EDCA parameter elements

[0520] D. Include silent elements

[0521] E. Modify DSSS parameter set

[0522] F. Modify CF parameter set elements

[0523] G. Modify HT operation elements

[0524] H. Includes wide bandwidth channel switching elements

[0525] I. Includes channel switching packaging elements

[0526] J. Include operating mode notification elements

[0527] K. Include silent channel elements

[0528] L. Modify VHT operation elements

[0529] M. Modify HE operation elements

[0530] N. Insert broadcast TWT elements

[0531] O. Include BSS color change notification element

[0532] P. Modify MU EDCA parameter set elements

[0533] Q. Modify the spatial reuse parameter set elements

[0534] 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 to the AP MLD. The request information may 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 may send a response message "Accept". And, when the AP MLD rejects (or refuses) the request, the AP MLD may send a response message "Reject".

[0535] When the request is accepted, the AP can perform link (re)establishment by frame exchange of the link with the reselected AP starting from after the response message transmission. Conversely, when the request is rejected, the STA can continue to use the link of its initial connection as it is.

[0536] 3) General methods

[0537] According to a general method, the non-AP MLD may request link switching or reconnection based on the information currently carried (or possessed) by the non-AP MLD without any additional information request. The information used at this time may include information about the AP MLD and information about the non-AP MLD (e.g., information about per-link STR capability, information about link status (enabled / disabled), etc.) included in a previously received beacon or management frame, etc.

[0538] Unlike 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 may include information about the AP and information about the link to which the STA is to reconnect. When the AP MLD having received the request message accepts the request, the AP MLD may send a response message "Accept". And, when the AP MLD rejects (or refuses) the request, the AP MLD may send a response message "Reject".

[0539] When the request is accepted, the AP can perform link (re)establishment by frame exchange of the link with the reselected AP starting from after the response message transmission. Conversely, when the request is rejected, the STA can continue to use the link of its initial connection as it is.

[0540] Detailed examples of AP MLD and non-AP MLD operations according to the general method can be found in Fig.32 describe.

[0541] Fig.34 The operations of AP MLD and non-AP MLD for link switching or reconnection are shown.

[0542] Reference Fig.34 , for reasons of ensuring QoS, STA 2 may want to switch its link directly. If STA 2 has existing information received from the AP MLD (e.g., information received through a beacon frame or a management frame, etc.), or if STA 2 has already determined the link to which it wishes to reconnect, STA 2 can request link switching or reconnection without any separate information request.

[0543] STA 2 can send STA information (e.g., STAID, etc.) and information about the link to be switched (e.g., link ID or AP BSS information, etc.) by including the corresponding information in a link switching request frame. When the AP MLD having received the request frame accepts the request, the AP MLD can send a link switching response frame "Accept" to STA 3 through the existing link 2. Thereafter, after performing a link (re)establishment procedure, STA 2 which is not the AP MLD can reconnect to AP 3.

[0544] Implementation of anchor link switching and reconnection

[0545] Depending on the implementation, the AP MLD may support anchor links. When the AP MLF supports anchor links, additional details are considered in the above implementations of link switching and reconnection.

[0546] The AP MLD may support one anchor link or more than one anchor link, and the AP MLD may provide information about the one anchor link or more than one anchor link to the non-AP MLD through the anchor link list information / element. The non-AP MLD may select one link or more than one link from the above anchor link list, and may use the selected link. The remaining links that are not selected as anchor links may operate as non-anchor links.

[0547] Anchor links and non-anchor links have a trade-off relationship in terms of power consumption and data load. That is, when a non-APMLD uses one anchor link, the amount of power consumption can be reduced. However, it may be difficult to ensure data (more specifically, data of beacons and management frames) transmission QoS. In contrast, when multiple anchor links are used, data transmission QoS can be ensured. However, the amount of power reduction may be reduced.

[0548] Therefore, the non-AP MLD should be able to dynamically request reselection on the anchor link for efficient data exchange. Therefore, in the following, an implementation scheme in which the non-AP MLD dynamically requests anchor link switching / reselection may be proposed.

[0549] First, the MLD structure that supports anchor links can refer to Fig.35 describe.

[0550] Fig.35 An example of an MLD structure supporting an anchor link is shown.

[0551] Reference Fig.35 , among the 5 links, the AP MLD can use 2 links (i.e., AP 1 and AP 4) as anchor links. The non-AP MLD can use one anchor link by selecting Link 1 from the two links used as anchor links. The remaining links of the non-AP MLD can be connected to non-anchor links (Link 2, Link 3). That is, the non-AP MLD should always perform monitoring on Link 1 for beacon and management frame reception.

[0552] According to an embodiment, STA 1 may request an initially used anchor link from the anchor link of AP 1 to the anchor link of AP 4 for reasons of load balancing, etc. To switch the anchor link, the above-described embodiments related to link switching may be applied.

[0553] However, among the links supported by the AP MLD, the anchor link is limited to only some links. Therefore, the AP MLD may have a separate anchor link list. The non-AP MLD (or STA) should select one of the links included in the anchor link list and then request switching or reconnection. In addition, since the non-AP MLD should have at least one or more anchor links, when requesting link switching or reconnection, the non-AP MLD should request anchor link switching while considering this requirement.

[0554] For the above implementation, the AP MLD needs to provide the non-AP MLD with "anchor link list" information. The above term "anchor link list" is only exemplary, and thus other various term configurations / expressions may be used.

[0555] - "anchor link list" (element / field): This is information about the anchor link list supported by the current AP MLD. For example, the information about the anchor link list supported by the current AP MLD may 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 anchor lists among the links included in the list.

[0556] The above information (e.g., "anchor link list" (element / field)) may be included in an existing beacon or management frame and then transmitted, or in the case of the above request method, the above information may be included in an information response message and may be transmitted together to the non-AP MLD.

[0557] Therefore, in the case where the non-AP MLD requests to switch the anchor link it is using, the non-AP MLD should be informed in advance of the information about the currently supported anchor link list. However, if the non-AP MLD is not informed (or does not know) the anchor link list information or wishes to obtain the latest information, the non-AP MLD can obtain the corresponding information from the AP MLD using the request method.

[0558] The STA may request to switch or reconnect to only one link in the anchor link list. If the STA requests to switch or reconnect to another link not included in the list, the AP MLD may send a rejection message to the STA.

[0559] When requesting anchor link switching or reconnection, there are details that should be considered in addition to the existing link switching method. The case where a non-AP MLD STA switches its anchor list can be roughly divided into two cases.

[0560] The first case corresponds to a case where a STA already connected to an anchor link switches to another anchor link of an AP MLD for reasons such as load balancing (AP switching of anchor link). The second case corresponds to a case where a STA (already) connected to an anchor link is disabled for reasons such as power status, so another STA other than an AP MLD reconnects to the anchor link (STA switching of anchor link).

[0561] The first case may operate similarly / identically to the above-described embodiments of link switching and reconnection. However, when reselecting a link, the STA should only select a link from the list of anchor links supported by the AP MLD. In the event of selecting another link, the AP MLD may send a rejection response message.

[0562] The second case requires additional considerations. An example of the second case can be found in Fig.34 describe.

[0563] Fig.36An example of a situation where an anchor link switch or reconnection is required is shown.

[0564] Reference Fig.36 In the case of non-AP MLD STAs, the state of STA1 may be disabled for various reasons (e.g., power off, etc.). At this time, since both STA2 and STA3 are currently connected to the non-anchor link, either of the two STAs should reconnect to the anchor link.

[0565] like Fig.36 As shown, when the non-AP MLD needs to reconnect to the anchor link, the non-AP MLD may try to reconnect one of STA 2 or STA 3 to the anchor link.

[0566] For example, when the non-AP MLD knows (or has) information about the anchor link list supported by the AP MLD, the non-AP MLD can select a suitable link and can request link switching.

[0567] As another example, when the non-AP MLD has no information on the anchor link list supported by the AP MLD, the non-AP MLD may obtain information through an information request to the AP MLD, and may then select a suitable link and request link switching.

[0568] The detailed examples of AP MLD and non-AP MLD operations according to the above embodiments can be referred to. Fig.37 describe.

[0569] Fig.37 The operation of AP MLD and non-AP MLD for anchor link switching or reconnection is shown.

[0570] Reference Fig.37 , in the case that STA1 connected to the anchor link is disabled, the non-AP MLD needs a new anchor link connection. At this time, the non-AP MLD can disconnect the initial connection of STA3 with AP3 via the non-anchor link and can try to reconnect to the anchor link.

[0571] For example, STA3 may attempt to connect to AP 1 that was initially used as an anchor link. As another example, STA 3 may attempt to establish a connection with a new AP 4 based on various information.

[0572] The process of selecting a new anchor link may be performed similarly / identically to the above-mentioned embodiments of link switching and reconnection. For example, STA 3 may request reconnection by selecting an anchor link recommended by the AP or by directly selecting an anchor link by STA 3 itself. After completing the anchor link reconnection, the link of STA 3 may operate as an anchor link.

[0573] Elements / fields containing information related to the anchor link

[0574] According to an embodiment, when information about an anchor link supported by the AP MLD changes, or when the STA directly requests information about the anchor link, the AP MLD may send corresponding information (i.e., information about the switched anchor link or information about the anchor link requested by the STA) to the non-AP MLD.

[0575] For example, the information may be included in a beacon frame as information about the anchor link currently in use and then may be transmitted, or the information may be included in a separate management frame and then may be transmitted.

[0576] The information about the anchor link may include an "anchor link list" element indicating the above-mentioned anchor links supported by the AP MLD and information indicating use or non-use of a per-STA anchor link.

[0577] Hereinafter, a new element including the above information about the anchor link may be proposed. The newly proposed element may be configured as described below.

[0578] 1) "Anchor Link Indication" element (or field) The "anchor link indication" element may include information related to the use or non-use of the anchor link of each STA connected to the AP MLD. That is, the "anchor link indication" element may be an element / field indicating the use or non-use of the anchor link per link or per STA of the non-AP MLD.

[0579] 2) "Per Anchor Link STA Ratio" Element (or Field) : The STA ratio per anchor link element may include information on the ratio or number of STAs connected per anchor link. However, in this document, only STAs using the anchor link as their link may be considered. In other words, even if the AP MLD supports the first link as an anchor link, STAs using the first link as a non-anchor link may not be included in the STAs connected to each anchor link (or STAs connected per anchor link).

[0580] According to an embodiment, in all the processes of the above-mentioned embodiments of anchor link switching or reconnection, these elements may be included in the frame as additional information when necessary.

[0581] For detailed examples of elements, see Fig.36 to describe.

[0582] Fig.38 and Fig.39 Detailed examples of elements for anchor link reconnection are respectively shown.

[0583] Reference Fig.38 and Fig.39 , the information related to the anchor link can be sent through the anchor link list element (or field), the anchor link indication element (or field) and / or the per-anchor link STA ratio element (or field). In other words, the element for anchor link reconnection may include the anchor link list element (or field), the anchor link indication element (or field) and / or the per-anchor link STA ratio element (or field).

[0584] According to an embodiment, as described above, the anchor link list element may 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 may be indicated based on the link ID or APBSS information, etc. In other words, the link list currently supported by the AP MLD may be configured based on the link ID or AP BSS information.

[0585] According to an embodiment, the anchor link indication element may 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 may be indicated by a per-link indication bitmap (i.e., Fig.36 As another example, the use or non-use of the anchor link of all STAs may be indicated by a bitmap (ie, Fig.37 ).

[0586] As an example, when the information related to the use or non-use of the anchor link is indicated by the indication bitmap according to the link ID, the STA can verify the current anchor link based on the anchor link list element value. Therefore, the STA can verify the ratio of STAs connected to each anchor link. At this time, the indication bitmap field of the non-anchor link can be omitted to reduce the overhead.

[0587] In the bitmap, when the value of one of the bits is equal to 1, this bit may 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 may indicate that the link currently connected to the STA is a non-anchor link. The implementation of using a bitmap to indicate the connection or disconnection of each STA anchor link is only exemplary. And, therefore, information related to the connection or disconnection of each STA anchor link can be sent through various other implementations.

[0588] According to an embodiment, the ratio of STAs of all links supported by the AP MLD may also be sent. According to an embodiment, the STA ratio element per anchor link may include information about the usage ratio or number of actual anchor links of STAs per anchor link. This has the effect of reducing overhead, for example, by indicating information only for the anchor links indicated in the anchor link list element.

[0589] Examples of configuring the value of the per-anchor-link STA ratio element may be described below.

[0590] For example, the AP MLD may include 5 APs (ie, AP 1 to AP 5), and AP 1 may be connected to the STA through link 1. AP 2 may be connected to the STA through link 2. AP 3 may be connected to the STA through link 3. AP 4 may be connected to the STA through link 4. And, AP 5 may be connected to the STA through link 5.

[0591] AP MLD may support 2 links out of 5 links (ie, link 1 to link 5) as anchor links. Link 1 and link 4 may be supported / used as anchor links.

[0592] A total of 10 STAs may be connected to link 1 (or AP 1), and 7 STAs may use link 1 as an anchor link. This may be expressed as a ratio of 70%, and this may be expressed as a value of 7.

[0593] A total of 20 STAs can be connected to link 4 (or AP 4), and 5 STAs can use link 4 as an anchor link. This can be expressed as a ratio of 25%, and this can be expressed as a value of 5.

[0594] By sending the per-anchor-link STA ratio element together with the above-mentioned per-link STA ratio element information, more accurate information can be sent to the STA. Generally, since anchor links can have a relatively larger amount of data traffic than non-anchor links, the per-anchor-link STA ratio element can be used as useful information for STAs that intend to reselect their anchor links.

[0595] The non-AP MLD may verify whether the link to which the non-AP MLD is connected is an anchor link, the connection rate of STAs per anchor link, and the ratio of the anchor link actually being used based on the above information (or elements).

[0596] In addition, when the AP MLD transmits information about other links (i.e., all links) through the above elements, the STA can verify the connection rate and actual usage rate of each STA of all anchor links of the AP MLD based on one frame. Therefore, when the STA reselects the anchor link to be used, this information (or element) can be used.

[0597] Therefore, according to the implementation method of anchor link switching or reselection, by using not only the various link information used in the implementation method of link switching or reselection (for example, information about the BSS load of each AP or information about the STR capacity of each link, etc.), but also using the above-mentioned information about the anchor link (for example, anchor link list information, information indicating the use or non-use of the anchor link for each STA or information about the actual STA usage rate of each anchor link, etc.), more suitable anchor link switching or reconnection can be performed.

[0598] Signaling to indicate link switching and reconnection methods

[0599] In order to indicate the method proposed above, an agreement process between the AP MLD and the non-AP MLD may be required through negotiation between the AP MLD and the non-AP MLD. To this end, a signaling method for implementing the method proposed below in this specification may be proposed.

[0600] First, in order to indicate the method proposed above, a new element may be proposed. Hereinafter, although an embodiment related to signaling for indicating a link switching and reconnection method will be described, the corresponding embodiment may also be applied to an embodiment related to signaling for indicating an anchor link switching and reconnection method.

[0601] The signaling process for indicating the link switching and reconnection method can be performed during or after the multi-link establishment. In addition, the new elements proposed below can be used in the signaling process for indicating the link switching and reconnection method. For example, these elements can be included in the (re) association frame of the existing technical specification or in the new frame.

[0602] Information Acquisition Methods (IOM) Capability Elements

[0603] The IOM capability element may include information related to enabling or disabling of a method of additionally obtaining information of a multilink. For example, in the process of exchanging messages for operation negotiation (or agreement) between the AP MLD and the non-AP MLD during the multilink establishment process (e.g., a capability negotiation process), an IOM capability value may be present in an element of the message. Furthermore, the presence of the IOM capability value in the element of the message may indicate support for the IOM capability.

[0604] According to an embodiment, when an AP MLD supports the IOM capability, the AP may be provided with internal shared information of other APs and may have (or possess) information of other APs. An MLD that does not have any shared information of other APs cannot support the IOM capability.

[0605] According to an embodiment, when the value of the IOM capability element is configured as a first value (e.g., 1), this may mean that the IOM capability element enables the IOM and uses the indicated capability to operate the IOM. Conversely, when the value of the IOM capability element is configured as a second value (e.g., 0), this may mean that the IOM capability element disables the IOM.

[0606] According to an embodiment, the IOM capability element may include various fields / elements for indicating various operations. For example, the IOM capability element may also include various fields / elements to be described below. However, depending on the case where the AP MLD requests a link switch and the case where the non-AP MLD requests a link switch, the fields / elements added to the IOM capability element may be configured differently. In addition, among the fields / elements added to the IOM capability element, at least some of the fields / elements may be omitted. For example, among the fields / elements added to the IOM capability element, the fields / elements including information that does not need to be indicated may be omitted.

[0607] Hereinafter, examples of various fields / elements defined / configured to obtain additional information related to multilink may be described below. Various fields / elements described below may be configured independently, or two or more fields / elements may be combined and then sent through various frames. For example, various fields / elements described below may perform operations included and defined in another element. As another example, various fields / elements described below may be used by being added to another element as an element or an independent field.

[0608] Method Type (or Method) Field / Element

[0609] 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 methods proposed above (e.g., the request method, the unsolicited method, the general method).

[0610] For example, based on the value of the method field / element being equal to a first value (e.g., 0), a request method may 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 may be indicated / used. Based on the value of the method field / element being equal to a third value (e.g., 2), a 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 a request method and a non-request method may be indicated / used.

[0611] As another example, 1 bit may 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 may 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 may be indicated / used.

[0612] As another example, 2 bits may be used as a method field / element. In this case, a single use or multiple uses of each method may be indicated.

[0613] Link scope fields / elements

[0614] When non-AP MLD requests information from AP MLD, the range of the requested links can be indicated by the Link Range field / element. The Link Range field / element may include information about whether the STA wishes to request information about all links within the AP MLD or whether the STA wishes to request information about some links within the AP MLD.

[0615] 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 may mean requesting 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), the link range field / element may mean requesting information about some links within the AP MLD.

[0616] At this time, when the value of the link range field / element is equal to the first value (e.g., 0), since this is a request for all links within the AP MLD, information about individual link indicators (e.g., the "Link Condition" field) is not required. Conversely, when the value of the link range field / element is equal to the second value (e.g., 1), since this is a request for some links within the AP MLD, link indicator information is required.

[0617] According to an embodiment, a field including link indicator information may be included in a multilink element. An example of a multilink element may be referred to Fig.40 to describe.

[0618] Fig.40 An example of a multi-link element is shown.

[0619] Reference Fig.40 , the multilink element may be included in various frames. For example, the multilink element may be included in a probe request frame. According to an embodiment, the multilink element may include a multilink control field. For example, the multilink control field may include a target MLD field. The target MLD field may include link indicator information.

[0620] 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 to a multilink element. Fig.41 describe.

[0621] Fig.41 Another example of a multi-link element is shown.

[0622] Reference Fig.41 , the multilink element may also include a link range field. Fig.41 In the embodiment, although the link range field is configured as a concatenation of the multilink control field, the present disclosure shall not be limited thereto. According to an embodiment, the link range field may be included in the multilink element in various formats.

[0623] As described above, by using the link range field together with the MLD MAC address field, this can indicate whether the field means information request for all links within the corresponding MLD or whether the field requests information for some links. For example, when the value of the link range field is equal to the first value (e.g., 0), this means information request for all links. Therefore, since additional link indicator information is not required, the "Per STA Profile (x)" sub-element can be omitted.

[0624] According to an embodiment, the link range field may also be used by being added to another element instead of being included in the multilink element. Fig.42 describe.

[0625] Fig.42 An example of the field configuration proposed in this specification is shown.

[0626] Reference Fig.42 , the EHT PPDU (or MPDU) may include a link range field, an information range field, a link condition field and / or an information condition field. Fig.42 As shown, various fields proposed in this specification can be used together in an integrated (or combined) format to indicate the scope and conditions of information that the STA requests from the AP MLD.

[0627] According to an embodiment, when requesting information to the AP MLD, the STA may include the proposed respective fields to the request message independently, and may omit some fields if not required.

[0628] Hereinafter, the link condition field, the information condition field, and other various fields / elements shown in the figure may be additionally described.

[0629] Information scope fields / elements

[0630] When a non-AP MLD requests information, the Information Scope field may be used to indicate the scope of the information.

[0631] For example, when the value of the information range field is equal to a first value (e.g., 0), the information range field may indicate that only part of the information carried by the AP is provided. And, when the value of the information range field is equal to a second value (e.g., 1), the information range field may indicate that all information (or the entire information) carried by the AP is provided.

[0632] According to an embodiment, although the information range field may 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 information to be provided (e.g., all information or part of the information) may be included in the information range field. For example, a subfield for indicating the range of information to be provided may be defined / configured as a full / partial subfield.

[0633] According to an embodiment, a subfield for indicating whether to provide all information or only the changed information among all information may be newly proposed. In other words, the newly proposed subfield may indicate whether to provide all information or only the changed information among all information.

[0634] For example, a subfield for indicating whether all information is to be provided or whether only changed information among all information is to be provided may be defined / configured as an update-only subfield.

[0635] When the STA wishes to receive only changed (or updated) information, the value of the Update Only subfield may be configured to 1. In other words, when the STA wishes to receive only changed (or updated) information, the STA may set the Update Only subfield value to 1. For example, when the Update Only subfield value is set to 1, according to the request method, when the STA requests information, the AP (or AP MLD) may send only changed information (i.e., updated information) among the requested information. As another example, when the Update Only subfield value is set to 1, according to the non-request method, the AP may notify only changed information within the information range configured by the STA.

[0636] According to the above example, in order to receive only the changed information, an update-only 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 may be defined / configured.

[0637] According to the above embodiment, the range of information that the STA can request can be configured as updated information or all information. In this case, the STA that does not want a large amount of frame overhead can request to receive only the changed information. Therefore, various overheads can be reduced.

[0638] Link Condition Fields / Elements

[0639] The link condition field may be used to indicate a specific link being requested. In other words, the link condition field may include information about a specific link being requested. The link condition field may be used when the STA wishes to receive only information about a specific link from the AP.

[0640] The link condition field may be marked (or indicated) by a link identifier (e.g., link ID, BSSID). In other words, the link condition field may include information related to the link identifier (e.g., link ID, BSSID). In other words, in order to specify a link for obtaining information, a link identifier may be used.

[0641] For example, when the STA connected to link 1 wishes to request only information about link 2 and link 3 from the AP, the STA may 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 value of the above-mentioned information range field is equal to 1, all information corresponding to link 2 and link 3 may be sent. As another example, when the value of the above-mentioned information range field is equal to 0, only part of the information specified by the STA in link 2 and link 3 may be sent. According to an embodiment, the part of the information specified by the STA may be determined by the information condition field (to be described below).

[0642] 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 may determine that there is no link condition. Therefore, the AP may provide / transmit information related to all links to the STA.

[0643] Information Condition Fields / Elements

[0644] The information condition field may be used to indicate a specific type of information being requested. In other words, the information condition field may be used when the STA wishes to receive only specific information from the AP.

[0645] For example, the information condition field may be used only when the information range field is set to 0. As another example, the information condition field may be used to allow the STA to indicate specific information even when the information range field is not present.

[0646] For example, information that the STA can specify (eg, BSS load, STR capability, etc.) can be indicated by a bitmap in the information condition field. For example, the information type, indication method, or bit order indicated by the AP can be configured differently.

[0647] According to an embodiment, the information condition field may be used together with the link condition field described above. According to an embodiment, the information condition field may send request information of various conditions to the STA (or AP) based on a combination of various fields / elements.

[0648] According to an embodiment, in order to allow STA to request specific information, elements of existing specifications may be reused. For example, in order to allow STA to request specific information, a request IE or an extended request IE may be used. Detailed examples of request IE or extended request IE may be described below.

[0649] Fig.43 A detailed example showing the format of the request element.

[0650] Reference Fig.43 , the request element may include an element ID field, a length field, and / or a requested element ID field. For example, the element ID field may include information indicating that the element is a request element. The length field may include information related to the number of octets following the length field. The requested element ID field may include information about the element ID to be requested. The requested element ID field may include a list of requested element IDs, and the list of element IDs may be listed in increasing order (or ascending order) of the element IDs.

[0651] Fig.44 A detailed example of the extended request element format is shown.

[0652] Reference Fig.44 The extended request element may 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 may be Fig.43 The Element ID field and Length field of the Requested Element ID field may be configured similarly. The Element ID Extension field may be combined with the Element ID field to configure an extended element ID. The Requested Element ID field may include one of the element IDs for indicating an extended element. The Requested Element ID Extension field may include a 1-octet element ID extension value.

[0653] Reference Fig.43 and Fig.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.

[0654] For example, when the STA indicates an information list for which it wishes to receive a response by using the requested element ID, the AP may include the corresponding information in a probe response frame or an information response frame and transmit it.

[0655] Therefore, according to the implementation of this specification, this element (request element or extended request element) can be reused as / used as an indicator for requesting specific information. For example, this element can be used together with a link identifier (e.g., Link identifier) ​​to request the desired information of the desired link.

[0656] For example, in order to request the BSS load information of AP 2, the STA may use the request element and the link identifier. The STA may include the element ID of the BSS load information through the request element. And, the STA may indicate AP 2 through the link identifier. Therefore, the STA may request the BSS load information of AP 2 based on the request element and the link identifier.

[0657] According to an embodiment, the above-mentioned element ID information can be used to indicate specific information of a specific AP in various combinations together with (or with) link identifier information. According to an embodiment, the above-mentioned request element and / or extended request element can be used / reused even in the case of defining a new frame for requesting information instead of an existing frame.

[0658] In the existing technical specifications, the PV1 probe response option element is used to request specific information. Therefore, in an embodiment in which specific information is indicated, the PV1 probe response option element may be used.

[0659] Fig.45 A detailed example of the PV1 Probe Response Option Element format is shown.

[0660] Reference Fig.45 ,PV1 Probe Response Option Element can be used to request optional information by using the information that the STA wants as a probe request. For frequently used information, a probe response option bitmap can be used to indicate individual information sets.

[0661] However, while considering MLD, the EHT specification should be able to provide information on multiple links. Therefore, the STA can use the bitmap indicator together with the link identifier to request specific information for various combinations of specific links, as shown in Tables 21 to 26.

[0662] According to an embodiment, optional information (e.g., STR capability) may be newly defined in the EHT specification along with multilink. Therefore, when the PV1 probe response option element is used / reused, a bitmap of information that needs to be newly defined or additionally obtained may be newly defined or additionally defined in the EHT specification. The probe response option bitmap may be configured as shown in Tables 21 to 26 below.

[0663] When the i-th bit of the probe response group bitmap is configured to 1, the probe response option bitmap subfield i may be included in the PV1 probe response option element.

[0664] Table 21 shows an example of the probe response option bitmap subfield 0.

[0665] Table 22 shows an example of the Probe Response Option Bitmap Subfield 1.

[0666] Table 23 shows an example of the Probe Response Option Bitmap Subfield 2.

[0667] Table 24 shows an example of the Probe Response Option Bitmap Subfield 3.

[0668] Table 25 shows an example of the Probe Response Option Bitmap Subfield 4.

[0669] Table 26 shows an example of the Probe Response Option Bitmap Subfield 5.

[0670] [Table 21]

[0671]

[0672] [Table 22]

[0673] Bit position Subfield Requested Items refer to 0 Request RPS RPS Elements RPS Elements 1 Requesting page slices Page Slice Elements Page Slice Elements 2 Request TSF timer accuracy TSF timer precision elements TSF timer precision elements 3 Request S1G relay discovery S1G Relay Discovery Elements S1G Relay Discovery Elements 4 Request S1G sector operation S1G Sector Operation Elements S1G Sector Operation Elements 5 Request short message beacon interval Short Beacon Interval Element Short Beacon Interval Element 6-7 Reserve

[0674] [Table 23]

[0675]

[0676] [Table 24]

[0677] Bit position Subfield Requested Items refer to 0 Request measurement pilot transmission Measurement pilot transmission elements Measurement pilot transmission elements 1 Requesting multiple BSSIDs Multiple BSSID elements Multiple BSSID elements 2 Request RM to enable capabilities RM Enablement Capability Elements RM Enablement Capability Elements 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 elements Antenna elements 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

[0678] [Table 25]

[0679] Bit position Subfield Requested Items refer to 0 Request to move a domain Mobile Domain Elements Mobile Domain Elements 1 Request QoS service capability QoS service capability elements QoS service capability elements 2 Request channel usage Channel usage elements Channel usage elements 3 Request time advertisement Time advertising elements Time advertising elements 4 Request time zone Request time zone element Request time zone element 5 Request IBSS Parameter Set IBSS Parameter Set Elements IBSS Parameter Set Elements 6-7 Reserve Reserve

[0680] [Table 26]

[0681] Bit position Subfield Requested Items refer to 0 Request intercommunication Interoperable Elements Interoperable Elements 1 Request Advertising Agreement Advertising Protocol Elements Advertising Protocol Elements 2 Request roaming alliance Roaming Alliance Elements Roaming Alliance Elements 3 Request Emergency Alert Identifier Emergency Alert Identifier Element Emergency Alert Identifier Element 4 Request QLoad Report QLoad Report Elements QLoad Report Elements 5 Request Multiband Multiband elements Multiband elements 6 Request multiple MAC sublayers Multiple MAC sublayer elements Multiple MAC sublayer elements 7 Request to reduce neighbor report Reduced Neighbor Report Elements Reduced Neighbor Report Elements

[0682] According to an embodiment, in order to request specific information about multilinks, the probe response option bitmap subfield 6 or 7 may be newly defined / configured.

[0683] Transmit periodic fields / elements

[0684] When the STA wishes to receive information using the unsolicited method, it may indicate whether the STA periodically receives or aperiodically receives a message including the information through the transmission periodicity field.

[0685] For example, when the STA wishes to receive information aperiodically, the AP may inform updated information every time an update occurs in the information of another AP.

[0686] As another example, when the STA indicates that information is to be received periodically, a message including the information may be received at a periodic interval configured by the STA.

[0687] According to an embodiment, the transmission periodicity field may be configured on 1 bit. When the value of the transmission periodicity field is set to 1, the STA may receive / obtain information through a periodic method of periodically receiving a message. When the value of the transmission periodicity field is set to 0, the STA may receive / obtain information through an aperiodic method of aperiodic receiving a message.

[0688] Transmission Interval Field / Element

[0689] According to an embodiment, when a STA wishes to periodically receive information about another AP, the STA can directly configure the interval (or transmission cycle period). The STA can send information about the interval at which information about another AP is to be received based on the transmission interval field. However, in this article, the interval should be configured to be shorter than the beacon transmission interval. For example, when using a FILS discovery frame, the interval should be configured to be 20us.

[0690] As described above, the transmission interval may be defined as a separate field within the element indicating the transmission interval, and may also be defined as a subfield within the transmission periodicity field.

[0691] According to an implementation manner, the fields / elements defined / configured to obtain additional information related to multilink are not limited to the above-mentioned fields / elements, and various other fields / elements may also be configured.

[0692] 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. In addition, after completing the multi-link establishment process, the MLD can update the negotiation details between the MLDs through a separate message exchange.

[0693] According to an embodiment, when the IOM capability is enabled, the AP MLD and the non-AP MLD may operate based on an embodiment of link switching and reconnection.

[0694] Hereinafter, exemplary operations of the AP MLD and the non-AP MLD when the IOM capability is enabled may be described. For example, by causing the non-AP MLD to send the above-mentioned fields / elements to the AP MLD, the non-AP MLD may request the AP MLD for additional information of the multilink. The non-AP MLD may send the above-mentioned fields / elements including the IOM capability element to the AP MLD. The fields / elements including the IOM capability element are merely exemplary. And, therefore, the IOM capability element may also be sent through an independent field / element.

[0695] For example, during the multi-link establishment process, the non-AP MLD may send an IOM capability element including "method field = 0" and "information range field = 1" to the AP MLD, and the non-AP MLD may negotiate with the AP MLD on this. In this case, after the multi-link is established, the non-AP MLD may operate using a request method. Then, when requesting information, the non-AP MLD may request information of the multi-link including all information included in the beacon (e.g., information about other APs). Therefore, the AP MLD may provide / send information about the link to the response message only when the AP MLD has received the request message from the STA. When receiving the request message, the AP MLD may send a response message including information about all links within the AP MLD to the STA. The information about all links within the AP MLD may include all information included in the beacon.

[0696] As another example, the non-AP MLD may send an IOM capability element including "method field = 1", "information range field = 0", "link range = link id 2", "information condition field = (value indicating BSS load through bitmap)" to the AP MLD, and the non-AP MLD may negotiate with the AP MLD on this. In this case, after the multi-link is established, the non-AP MLD may operate using the non-request method. Therefore, even without a separate request message, the AP may send the BSS load information of the link 2 to the STA through a separate message.

[0697] 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 subfield = 1", "information condition field = (value indicating BSS load through bitmap)" to the AP MLD, and the non-AP MLD may negotiate with the AP MLD on this. In this case, after multi-link establishment, the non-AP MLD may operate using the request method. Therefore, the AP MLD (or AP) may include only updated (or changed) information among the BSS load information of all APs of the APMLD connected when the STA requests information in the response message, and then may send the message to the STA.

[0698] Hereinafter, in the present specification, various examples of new elements that STA can use to request partial information (i.e., target information) of other APs of the connected AP MLD are described. 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 as various other terms.

[0699] Fig.46 An example of an MLD request element is shown.

[0700] Reference Fig.46 , the MLD request element 4600 may include an element ID field, a length field, an element ID extension field, a link ID quantity field and / or a link ID field.

[0701] For example, when the STA requests information of a specific AP, the link ID number field may include information indicating the number of APs (ie, links) requested by the STA.

[0702] For example, the link ID field may include indicator information of the AP requested by the STA.

[0703] For example, the STA may transmit the MLD request element 4600 by including the element in a probe request frame. The AP having received the probe request frame may transmit a probe response frame including all information of the AP indicated in the MLD request element 4600.

[0704] 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 an existing standard by including the element together with (or together with) the MLD request element in a 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.

[0705] Fig.47 Another example of an MLD request element is shown.

[0706] Reference Fig.47 ,Apart from Fig.46 In addition to the illustrated MLD request element 4600, the MLD request element 4700 may also include a requested element ID / requested element ID extension field.

[0707] For example, when the STA requests information of a specific AP, the link ID number field may include information indicating the number of APs (ie, links) requested by the STA.

[0708] For example, the link ID field may include indicator information of the AP requested by the STA.

[0709] For example, when the STA requests specific information (ie, 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.

[0710] 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 identified as an extended element ID, and therefore, 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.

[0711] At this time, although the information corresponding to the requested element ID / requested element ID extension field can be defined in the form of a field, the information can also be defined as a new element and can be included in the MLD request element in the form of a sub-element. The new element can be as follows Fig.48 Definition / configuration shown.

[0712] Fig.48 Another example of an MLD request element is shown.

[0713] Reference Fig.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 using the MLD request element 4800, the MLD request element may be indicated as an element without being distinguished as an existing request element or an extended request element. And, therefore, this has the effect of reducing overhead.

[0714] For example, when the STA transmits the MLD request element 4800 by including the element in the probe request frame, the AP having received the request message (ie, the probe request frame) may transmit a probe response frame including information of the AP indicated in the MLD request element 4800 .

[0715] 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 one of complete information or partial information. The element ID value information defined in this standard is defined in the element 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 the same as the previous standard. For example, the request element and the extended request element including the "Requested Element ID" and the "Requested Element ID Extension" can be as follows. Figure 43 to Figure 44 For example, the request element and the extended request element may be configured as shown in Table 27 and Table 28.

[0716] [Table 27]

[0717]

[0718] [Table 28]

[0719]

[0720] According to an embodiment, when STA requests information from AP, STA can request information of other APs by including the elements in the probe request frame to send the proposed MLD request elements 4700 and 4800. The AP having received this can send only the information requested through the "Requested Element ID / Requested Element ID Extension" field among the information of the AP requested through the "Link ID" field by including the corresponding information in the probe response frame.

[0721] According to an embodiment, when the STA performs transmission after omitting the "Requested Element ID / Requested Element ID Extension" field, the AP having received this can send the complete information of the AP requested through the "Link ID" field by including the corresponding information in the probe response frame.

[0722] The various formats of the MLD request element proposed above may simply request the same information for all links. Since the STA may also request other information per link, various options for these requests may be proposed below.

[0723] 1) First, a format for requesting additional information per link may be proposed. This may be done as Fig.49 Configuration shown.

[0724] Fig.49 Another example of an MLD request element is shown.

[0725] Reference Fig.49In order to request other information per link, the existing request element or / and extended request element information per link may be included in the MLE request element 4900. At this time, a new field or element "Number of Elements" may be defined / configured to notify the length of the requested element. The "Number of Elements" information may mean the number of elements requested for link ID (x). The AP may verify the information differently requested per link based on the MLE request element 4900, and may send the information differently requested per link by including the corresponding information in the response frame.

[0726] According to an embodiment, the fields proposed in this specification may be used instead of the request elements and / or extended request elements previously defined in the prior art. Fig.50 Configuration shown.

[0727] Fig.50 Another example of an MLD request element is shown.

[0728] Reference Fig.50 , the MLD request element 5000 may include a "requested element ID / requested element ID extension" field. The various fields / elements included in the MLD request element 5000 shown in the figure may be omitted as needed.

[0729] 2) Secondly, when a STA requests information, a format can be proposed to distinguish between common information requested identically for all links and link-specific information requested differently for each link. This can be done as follows Fig.51 Configuration shown.

[0730] Fig.51 Another example of an MLD request element is shown.

[0731] Reference Fig.51 , the request element or / and the extended request element may be included in front of (or before) the link ID quantity field in the MLD request element 5100. The request element or / and the extended request element (first element) may mean an element of common information of a link common request indicated later.

[0732] The request element or / and the extended request element (second element) 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 per link. Individual fields or elements can be omitted as needed.

[0733] 3) Third, the fields proposed in this specification may be included in the MLD request element 5200 instead of the existing request element or / and the extended request element. Fig.52 Configuration shown.

[0734] Fig.52Another example of an MLD request element is shown.

[0735] Reference Fig.52 , the MLD request element 5200 may include a "Requested Element ID / Requested Element ID Extension" field. Individual fields or elements may be omitted as needed.

[0736] For example, the request element or / and the extended request element (first element) may be represented as elements of common information of a link common request indicated later.

[0737] The request element or / and the extended request element (second element) listed after the number of elements together with the link ID (X) placed after the link ID number field can represent element information per link request.

[0738] 4) Fourth, when a STA requests information, common information that is requested identically for all links can be indicated / sent together with the MLD request element through a separate request element or an extended request element. This can be as follows Fig.53 Configuration shown.

[0739] Fig.53 An example of an element for requesting public information is shown.

[0740] Reference Fig.53 When a STA requests information of multiple links of an AP MLD through a request frame, the commonly requested information can be indicated / sent through an existing request or / and an extended request element. In addition, the information requested differently for each link can be indicated / sent through an MLD request element.

[0741] 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 identify the information included in the request or / and extended request element as information for the link common request indicated in the MLD request element. Therefore, the AP may send the corresponding element information of all links indicated in the MLD request element by including the corresponding information in the response message.

[0742] In addition, the STA may request other information per link. In this case, based on the information indicated per link in the MLD request element, the AP may send other information per link by including the corresponding information in the response message.

[0743] Hereinafter, a technical feature that enables a STA to request partial information of other APs of a connected AP MLD using a multi-link (ML) information element (IE) defined in the EHT standard may be proposed.

[0744] Fig.54 An example of a multilink element format is shown.

[0745] Reference Fig.54 , in the EHT standard, it can be Fig.54 The multilink element (or ML IE) is defined / configured as shown to define per-link information. According to an embodiment, various elements or fields may be added to the multilink element according to the technical features to be proposed below.

[0746] For example, the Per STA Profile (x) sub-element may include various information of the corresponding link. The Per STA Control field of the Per STA Profile (x) sub-element may include content regarding the corresponding link ID and the range of information included in the corresponding sub-element.

[0747] As an example, the information (element) corresponding to the information requested by the STA may be listed in the per-STA profile (x) sub-element. In other words, the information (element) corresponding to the information requested by the STA may be sequentially transmitted within the per-STA profile (x) sub-element.

[0748] As an example, when non-inherited information is present, a non-inherited element may be included in a per-STA-profile(x) sub-element.

[0749] As an example, the complete profile within the per-STA control sub-element may include information for distinguishing (or identifying) the included information as complete information of the corresponding link or partial information of the corresponding link.

[0750] Therefore, by including the multilink element (or ML IE) configured / defined as described above in a request frame (e.g., a probe request frame), the STA can use the multilink element (or ML IE) when requesting partial information of other APs. Various implementations (or options) for this may be proposed below.

[0751] Hereinafter, in this specification, in order to perform MLD detection using ML IE, a restriction factor may be defined / configured as described below.

[0752] For example, a STA may use the ML IE from a probe request frame for MLD probe. For example, the element information (e.g., element x, element n) provided in the per-STA profile (x) may be omitted to reduce overhead. However, unlike the probe request frame, when the ML IE is used in an association request / response frame for association, the element information provided in the per-STA profile (x) should be included.

[0753] For example, when the information requested by the STA is the complete information of the link, a bit indicating the complete information may be configured in the per-STA control field. In this case, the element information list sent after the per-STA control field may be omitted.

[0754] As another example, when the information requested by the STA is partial information of the link, a bit indicating partial information may be configured in the per-STA control field. In this case, information related to the element ID may be sent after the per-STA control field.

[0755] The above-mentioned complete information / partial information may be included in the complete profile field. Therefore, when the complete profile field is configured by a bit indicating complete information, this may mean that the complete information of the link is requested. When the complete profile field is configured by a bit indicating partial information, this may mean that partial information of the link is requested.

[0756] Various options related to the situation where a STA requests partial information rather than all information (or complete information) of a specific element may be described in detail below.

[0757] According to an embodiment, information included in the ML IE may vary based on whether a corresponding element is included in an association frame or a sounding frame and whether the corresponding frame is a request frame or a response frame.

[0758] For example, when the ML IE is used when the STA performs a probe request, although the elements including various information in the per-STA profile (X) may be omitted, otherwise, the element information must be included. Therefore, 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 may be proposed hereinafter. In other words, the proposed control field may include information about 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.

[0759] Before describing the proposed control field, examples of multilink elements and multilink control field formats may be described first.

[0760] Fig.55 Another example of a multi-link element format is shown.

[0761] Reference Fig.55 The multilink element 5500 may include an element ID field, a length field, an element ID extension field, a multilink control field, an MLD MAC address field, and / or an optional sub-element field. Various fields / elements may also be included between the MLD MAC address field and the optional sub-element field.

[0762] Fig.56 An example of the multi-link control field format is shown.

[0763] Reference Fig.56 The multilink control field 5600 may include an MLD MAC address presence field. Various fields / elements may also be included in the multilink element 5500.

[0764] According to the implementation mode, it can be based on Fig.55 and Fig.56 The multilink elements and multilink control fields shown propose various fields / elements. Examples of the proposed fields / elements may be described below.

[0765] According to an embodiment, a field for indicating the format of a frame including the current multilink element may be added to the multilink control field element. This field may be defined as a field present per STA element. The name of the field may be configured differently and may also be redefined as needed.

[0766] For example, the per-STA element presence field may indicate whether there is per-STA element list information requested by the current ML IE. In other words, the per-STA element presence field may include information about whether there is per-STA element list information requested by the current ML IE.

[0767] As an example, when the value of the Per STA Element Presence field is equal to the first value (eg, 1), the Per STA Element Presence field may mean that various element information is included after the Per STA Control field within the Per STA Profile (x) field.

[0768] As another example, when the value of the Per-STA Element Presence field is equal to the second value (eg, 0), the Per-STA Element Presence field may mean that various element information is omitted after the Per-STA Control field within the Per-STA Profile (x) field.

[0769] The multilink control field including the per-STA element presence field configured as described above may be as follows: Fig.57 Configuration shown.

[0770] Fig.57 An example of the multi-link control field format is shown.

[0771] Reference Fig.57 , the multi-link control field 5700 may include an MLD MAC address presence field, a per-STA element presence field and / or a reserved field.

[0772] According to an embodiment, as described above, the information included in the ML IE defined in the EHT standard may vary based on whether the corresponding element is included in an association frame or a detection frame and whether the corresponding frame is a request frame or a response frame. Therefore, a field that can indicate this may be proposed. The proposed field may be included in the ML IE of the request / response frame. The proposed field may include information about the frame type currently transmitted by the STA. The content of the element (or the element configured by 0 or a variable) additionally configured based on the proposed field or the arrangement order of the elements may vary (or change).

[0773] The proposed field may also be referred to as a frame type field and may be defined / configured as described below.

[0774] Frame Type Field : This indicator indicates the frame type currently sent by the STA. The type of the frame including the current MLIE can be indicated based on the value of the frame type field.

[0775] For example, the value of the frame type field may be divided into 0: association request, 1: association response, 3: probe request, and 4: probe response, etc. As shown in the above example, although the frame type may be indicated according to an integer value, the frame type may also be indicated by a bitmap.

[0776] As another example, the frame type field may also be used to distinguish the MLD probe proposed in the EHT standard. And, in this case, 5: MLD probe request frame and 6: MLD probe response frame, etc. may be added to the frame type field value.

[0777] As described above, the frame type field may be used to indicate that the element configuration of the ML IE may change based on the frame type. According to an embodiment, each frame type may be arranged in a subfield format within the frame type field. When the subfield is set to 1, the frame type field may indicate the frame type corresponding to the subfield set to 1.

[0778] According to an embodiment, the STA may request partial information about a specific element instead of all information (or complete information). In this case, the multi-link information element (ML IE) may be configured differently. Hereinafter, various examples of the ML IE format and various examples of STA and AP operations may be described when the STA requests partial information about a specific element instead of all information (or complete information).

[0779] 1) First, a request element and / or an extended request element for indicating information that the STA is to request from the corresponding AP may be included in the per-STA profile (x) of the ML IE.

[0780] The AP that has received the request message indicating the corresponding information can verify the partial information of the link that the STA is 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 intended to be requested through the per-STA profile (x) in the ML IE and whether the currently requested information is complete or partial. Then, the STA can perform transmission after indicating the specific information to be requested additionally through the request element or / and the extended request element.

[0781] For example, a STA can request specific information desired by each link through the configured multilink element, such as Fig.58 shown.

[0782] Fig.58 Another example of a multi-link element format is shown.

[0783] Reference Fig.58 , the multilink element 5800 may include a request element or / and an extended request element. However, when requesting all information of the AP (i.e., complete information), the request element or / and the extended request element may be omitted. In addition, the element information arranged after the per-STA control field as described above may be omitted as needed.

[0784] 2) Secondly, the requested element ID / requested element ID extension field for indicating the information that the STA is to request from the corresponding AP may be included in the per-STA profile (x) within the existing ML IE. The requested element ID / requested element ID extension field may correspond to Figures 48 to 53 Requested Element ID / Requested Element ID Extension field described in .

[0785] The AP that has received the request message indicating the corresponding information can verify the partial information of the link that the STA is 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 intended to be requested through the per-STA profile (x) within the ML IE and whether the currently requested information is complete or partial. Then, the STA can perform transmission after indicating the specific information to be requested additionally through the requested element ID / requested element ID extension field.

[0786] For example, a STA can request specific information desired by each link through the configured multilink element, such as Fig.59 shown.

[0787] Fig.59 Another example of a multi-link element format is shown.

[0788] Reference Fig.59 , the multilink element 5900 may include a requested element ID / requested element ID extension field. However, when requesting complete information of the AP (i.e., all element information), the requested element ID / requested element ID extension field may be omitted. In addition, as described above, the element information arranged after the per-STA control field may be omitted as needed.

[0789] The format of the multilink element 5900 can send the element indication information defined in the 802.11 standard as one information set without distinguishing the information as 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.

[0790] 3) Third, by sending a request element or / and an extended request element for indicating the information that the STA wants to request from each AP, the STA can request information by distinguishing between common information requested for all APs and link-specific information. The ML IE format according to the above embodiment can refer to Fig.60 describe.

[0791] Fig.60 An example of a multilink element format and additional elements is shown.

[0792] Reference Fig.60 When a STA requests information of each AP through a request frame (e.g., a probe request frame), the STA may send the same request for part of the information, and the STA may request different information for each AP for another part of the information. Therefore, a multilink element 6000 and a request or / and an extended request element 6010 may be used / defined to indicate this.

[0793] For example, the request or / and extended request element 6010 (first element) can be used together with the ML IE in the request frame as an indicator for the AP from which the STA requests information through the request frame to request the same information. The first element can be sent after the multilink element 6000 in the request frame.

[0794] As another example, the request or / and extension element 6020 (second element) within the per-STA configuration file (x) may be used as an indicator indicating other information requested per AP.

[0795] However, as described above, the element information arranged after the Per STA Control field may be omitted as needed.

[0796] For example, the STA may mark (or indicate) information corresponding to the TIM element (eg, element 5=11) in the probe request frame in the request element 6010 (first element).

[0797] In addition, the STA may mark / indicate Link ID=1, Full Profile=0 in the Per-STA Control of the Per-STA Profile (x) within the ML IE 6000. (Conversely, when the value of the Full Profile is equal to 1, this may mean a request for all element information.) The STA may mark (or indicate) information corresponding to the BSS Load element in the Request element (e.g., Element ID=11).

[0798] In addition, the STA may mark / indicate Link ID=2 Full Profile=0 in the Per STA Control of the Per STA Profile (y) within the ML IE 6000. The STA may mark (or indicate) information corresponding to a non-inherited element in an Extended Request element (e.g., Element ID=255, Element ID Extension=56).

[0799] When transmitting a frame configured as described above (eg, a probe request frame), the AP may transmit a probe response frame including the following information.

[0800] -TIM element information for link 1 and link 2

[0801] -BSS load element information for link 1

[0802] - Non-inherited element information for link 2

[0803] Therefore, according to the above-mentioned embodiment, the STA may distinguish information requested according to the element hierarchy within a frame as common information or link-specific information, and may request other information per link.

[0804] 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 may be included in the multilink element. In this case, the STA can request information by distinguishing between common information requested for all APs and link-specific information. The ML IE format according to the above embodiment can refer to Fig.61 describe.

[0805] Fig.61 Another example of a multilink element format and additional elements is shown.

[0806] Reference Fig.61 When a STA requests information of each AP through a request frame (e.g., a probe request frame), the STA may send the same request for part of the information, and the STA may request different information for each AP for another part of the information. Therefore, a multilink element 6100 and a request or / and an extended request element 6110 may be used / defined to indicate this.

[0807] For example, the request or / and extended request element 6110 may be included in a request frame (e.g., a probe request) together with the multilink element 6100. The request or / and extended request element 6110 may mean that the STA requests partial information of the link to which the corresponding STA is connected (i.e., the associated AP).

[0808] For example, when the STA requests information of an AP that does not correspond to a link of the corresponding STA among the APs in the AP MLD connected to the STA, the relevant indication information may be included in the multilink element 6100 (or the 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, information commonly requested by the STA for other APs (i.e., APs that do not correspond to a link of the STA among the APs included in the AP MLD connected to the STA) may be indicated through the corresponding element.

[0809] The information commonly requested for other APs may be indicated by a request or / and extended request element 6120 within the ML IE 6100. In addition, the information differently requested for each other AP may be indicated by adding a request or / and extended request element 6130 after the per-STA control field within the per-STA profile (x).

[0810] At this time, when an indicator of an AP corresponding to a link of the STA but not to links of other STAs is included in the 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 of 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.

[0811] However, as described above, the element information arranged after the Per STA Control field may be omitted as needed.

[0812] According to the above embodiment, by distinguishing the information requested according to the element level in the frame as common information or link-specific information, the STA can request other information per link. To this end, in addition, a new field can be proposed to indicate whether the information requested by the corresponding ML IE distinguishes the common information in the multi-link control field.

[0813] As shown in the above embodiment, STA can represent the public information of the corresponding link according to the hierarchy of the request element or / and the extended request element. For example, based on whether there is a public information request, it can be determined in the request frame whether there is a request element or / and an extended request element before the per-STA profile (x) in the ML IE. Therefore, a control field for indicating this may be proposed below.

[0814] The proposed field may be defined as a public information presence field. The name of the proposed field may be configured differently and may also be defined as a different name.

[0815] For example, when the value of the Common Information Presence field is indicated as 1, when requesting information about other APs to the AP MLD, the STA may send a request element or / and an extended request element indicating a request for the same information by including the corresponding element before the Per-STA Profile (x) element. Also, link specific information differently requested per AP may be indicated by a request element or / and an extended request element included in the Per-STA Profile (x) element.

[0816] As another example, when the value of the common information present field is indicated as 0, the common information present field may mean that the STA does not have any information requested equally for other APs. In addition, the common information present field may mean that there is no separate request element or / and extended request element before the per-STA profile (x) element.

[0817] The multilink control field according to the above embodiment may be as follows Fig.62 Configuration shown.

[0818] Fig.62 An example of the multi-link control field format is shown.

[0819] Reference Fig.62 , the multi-link control field 6200 may include an MLD MAC address presence field, a public information presence field and / or a reserved field.

[0820] How to request critical update information

[0821] According to an embodiment, the STA may only make a partial request to the AP of the AP MLD for the critical update information. To this end, various embodiments (or options) may be proposed below.

[0822] 1) First, a "critical update request" field may be newly defined / configured to request critical update information of other APs.

[0823] Key Update Request Fields : 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 with the link indicator. In this case, this field can be used when requesting the system information defined by the critical update of a specific link.

[0824] When requesting information of other APs of the AP MLD, the STA may set the value of the Critical Update Request field to 1 together with the link indicator information in a request frame (eg, a probe request frame), and may then send the request frame.

[0825] The AP having received the request frame may transmit the received information by including the received critical update information of the indicated link in a response frame. The AP may transmit the change sequence element by including the change sequence element together with the critical update information in a response frame.

[0826] At this time, the critical update information may include various system information defined by critical update 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 critical update in the existing section 10.46.2, a new information set may be defined. The critical update information described in this specification may include the critical update information newly defined in the EHT standard.

[0827] For example, when the STA sends a critical update request field by setting the value of the corresponding field to 1, the AP may send a response frame according to existing operations. The critical update request field may be included in any element within the request frame and may be used by including it in the above-mentioned MLD request element or ML IE. An example of an ML IE including a critical update request field may refer to Fig.63 describe.

[0828] Fig.63 Another example of a multi-link element format is shown.

[0829] Reference Fig.63 When the STA requests information about a specific link from the ML IE 6300 in the probe request, the STA may request information corresponding to the specific link through the per-STA profile (x). At this time, the key update request field 6310 may be included in the per-STA control in the per-STA profile (x).

[0830] When the Critical Update Request field 6310 is set to 1, the AP may send a response frame including the current system information defined by Critical Update in Section 10.46.2 for the link indicated in the Per-STA Profile (x).

[0831] Fig.64 Another example of a multi-link element format is shown.

[0832] Reference Fig.64 , the critical update request field 6410 may be placed (or located) within the ML IE 6400. In this case, the STA may request critical update information for all links indicated by the per-STA profile (x).

[0833] For example, the STA may include the critical update request field 6410 in a location including public information within the ML IE 6400. And, after indicating the value of the critical update request field 6410 as 1, the STA may transmit a frame (e.g., a probe request frame). The AP having received the frame may transmit a response frame including critical update information of the link requested in the received frame (e.g., the probe request frame).

[0834] As another example, the STA may include the critical update request field 6410 in a subfield within the multilink control field within the ML IE 6400 and may then transmit the critical update request field 6410 .

[0835] As shown in the above examples, the critical update request field format (field or subfield or subelement, etc.) or the location of the critical update request field within the ML IE may be defined differently according to the standard definition.

[0836] Second, a change sequence element for requesting critical update information of other APs may be used.

[0837] In the 11ah standard, the STA can send a change sequence element by including the corresponding element in the probe request frame. The AP that has received the probe request frame can include the change sequence element as the key update version information currently carried by the AP in the compressed probe response frame together with only the key update information of the change of the corresponding link, and then send it. Therefore, the change sequence element can also be used in the EHT standard.

[0838] For example, the STA may include the change sequence element together with the link indicator of the other AP in the probe request frame and then send it. The AP that has received the probe request frame may include only the key update information of the change of the indicated link in the probe response and then send it. Thereafter, the AP may include the key update information of the change together with the change sequence element in the corresponding response frame and then send it.

[0839] For example, the change sequence element may be included in any element or sub-element within the request frame, and the change sequence element may also be used by being included in the above-mentioned MLD request element or ML IE.

[0840] Examples of multi-link elements including the above-mentioned change sequence elements can be found in Fig.65 describe.

[0841] Fig.65 Another example of a multi-link element format is shown.

[0842] Reference Fig.65, the change sequence element 6510 may be included in the ML IE 6500. The STA may transmit a frame (e.g., a probe request frame) including the ML IE 6500. The AP having received the frame may compare the change sequence field value of the corresponding AP for the link currently bearer indicated by the ML IE with the change sequence field value in the change sequence element 6510 transmitted by the STA. For example, when there is a change in the AP, the AP may include the changed critical update information in the probe response frame and then transmit it.

[0843] At this time, the change sequence element 6510 sent by the STA must include the change sequence information of all links of which the information is requested in the ML IE. Therefore, when using the existing change sequence element, additional link indicator information may be required.

[0844] In addition, new elements based on MLD may be additionally proposed in this specification hereinafter.

[0845] MLD changes sequence elements : This is an element of change sequence information that can include multiple links.

[0846] An example of MLD changing sequence elements can be as follows Fig.66 and Fig.67 Configuration shown.

[0847] Fig.66 and Fig.67 An example of an MLD change sequence element format is shown.

[0848] Reference Fig.66 , the MLD change sequence element can be configured by repeatedly arranging the change sequence value per link.

[0849] Reference Fig.67 , after indicating the number of links as “number of link IDs”, the MLD change sequence element may be configured by indicating each of link ID information and change sequence information.

[0850] In the following, an exemplary embodiment of using the MLD change sequence element may be described. First, the MLD change sequence element may be included in a multilink element. The multilink element may be as follows: Fig.68 Configuration shown.

[0851] Fig.68 Another example of a multi-link element format is shown.

[0852] Reference Fig.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 the respective received change sequence values ​​per link with the respective change sequence values ​​carried by the AP.

[0853] The AP may send critical update information for link changes corresponding to the 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 may omit the per-STA profile (x) sub-element.

[0854] According to an embodiment, a change sequence element defined in a prior art standard may be used. The change sequence element defined in a prior art standard may be as follows: Fig.69 Configuration shown.

[0855] Fig.69 Shows an example of changing the format of a sequence element.

[0856] Reference Fig.69 , the change sequence element 6900 may include an element ID field, a length field and / or a change sequence field.

[0857] According to an embodiment, the existing change sequence element may be directly used as is in the ML IE without modification. The STA may also request critical update information for each link update through the change sequence element.

[0858] Fig.70 Another example of a multi-link element format is shown.

[0859] Reference Fig.70 , the probe request frame may include the ML IE 7000. A change sequence element 7010 may be included in the per-STA profile (x) of the ML IE 7000. The change sequence element 7010 may indicate key update information of a change of a link indicated by the per-STA profile (x) request.

[0860] 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 changed information that the STA should update), the AP can send a response frame including the changed critical update information.

[0861] Third, in order to request critical update information of other APs, the Change Sequence field can be used together with the "Critical Update Request" field defined above. As an indicator that the STA has been used to request information of another AP, the "Critical Update Request" field has been defined / configured as described above. The previously defined / configured "Critical Update Request" field is described as follows.

[0862] Key Update Request Fields: 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 with the link indicator. In this case, this field can be used when requesting the system information defined by the critical update of a specific link.

[0863] According to an embodiment, the key update request field may be configured by 1 bit. The STA may use a 1-bit indicator to request a key update for a specific link. When the AP having received the request does not know the version of the key update information currently carried by the STA (i.e., the change sequence field value of the key update information carried by the STA), the AP must send a response message including all key update information of the requested link. The AP may include the key update information together with the change sequence element in the corresponding response frame and then send it.

[0864] Although the above implementation is a simple method, since the method may include overlapping transmission of information already carried by the STA, technical features that reduce related overhead may be required. Therefore, a multilink element format for these technical features may be proposed separately. An example of a multilink element format can be found in Fig.71 describe.

[0865] Fig.71 Another example of a multi-link element format is shown.

[0866] Reference Fig.71 STA may include a critical update request field 7120 as an indicator for indicating a critical update information request together with a change sequence field 7110 (or change sequence element, change sequence field) indicating version information of a critical update currently carried by the STA in a request frame and then send it.

[0867] At this time, the change sequence field 7110 may include information related to the indicator. In the EHT standard, the STA may receive the change sequence value of the AP of the AP MLD periodically connected through a beacon or a probe response. In addition, the STA may store the received change sequence value. Therefore, the STA knows the per-link change sequence value currently received by the STA.

[0868] Therefore, the change sequence field 7110 defined in the present specification may include information on the version (ie, change sequence value) of the key update information of the AP connected to the AP MLD that the STA previously obtained through a beacon or a probe response.

[0869] For example, when the value of the critical update request field 7120 is equal to 1, the critical update request field 7120 may 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 may mean that the STA does not request critical update information.

[0870] When the value of the critical update request field 7120 is equal to 1, since the critical update request field 7120 means a critical update information request, the change sequence field 7110 (or a change sequence element) may be included in the multilink element 7100 .

[0871] When the value of the critical update request field 7120 is equal to 0, the change sequence field 7110 (or the change sequence element) may be omitted.

[0872] That is, when the value of the Critical Update Request field is equal to 1, by causing the STA to 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., only the changed information that the STA needs to update) in the response frame and then send it.

[0873] And, when the value of the Critical Update Request field is equal to 0, in order to reduce overhead, the STA may omit the Change Sequence field (or Change Sequence element) and may then send a frame (eg, a Probe Request frame).

[0874] As described above, based on the key update request field value, it can be distinguished and then defined whether a change sequence field (or change sequence element) exists.

[0875] Different from the above example, according to the options, the values ​​of the key update request field and the change sequence field (or change sequence element) can be independently defined and used.

[0876] According to an embodiment, a critical update request field with a value of 1 may be included in a request message sent by the STA, or a case where a change sequence field (or change sequence element) is not included may occur. The AP having received this may assume that the STA wishes to receive all critical update information, not just updated critical update information. Therefore, the AP may include all critical update information in a response message and then send it.

[0877] Hereinafter, in the present specification, a method may be proposed in which a STA sends a key update request field together with previously obtained change sequence value information, and a method in which an AP compares the received change sequence value information with the change sequence value information carried by the corresponding AP and only includes the changed information in a response frame and then sends it.

[0878] In the embodiments described below, although the change sequence field (or the change sequence field field) is used to transmit the change sequence information of the link, the present disclosure will not be limited thereto. For example, the STA may also request the change information by using the change sequence element instead of the change sequence field. Since the embodiments using the change sequence element have been described in detail above, the following description omits the embodiments using the key update request field together with the change sequence element.

[0879] For example, when the STA includes the MLIE in the probe request frame and transmits for MLD probe, information for requesting the critical update may be included in the per-STA profile (x) sub-element for requesting per-STA information.

[0880] As an example, a critical update request field is included in the per-STA control field, and a change sequence field field including critical update information of the current STA may be placed (or located) within the per-STA configuration file (x).

[0881] For example, the critical update request field may be placed (or located) in the per-STA configuration file (x) together with the change sequence field, instead of the per-STA control field.

[0882] An example of a multilink element including the above-mentioned key update request field and change sequence field can be referred to Fig.72 describe.

[0883] Fig.72 Another example of a multi-link element format is shown.

[0884] Reference Fig.72 , the critical update request field 7210 and the change sequence field 7220 may be included in the per-STA configuration file (x) of the multilink element 7200. Although the critical update request field 7210 and the change sequence field 7220 may also be included in the per-STA configuration file (y), the information included therein may be configured differently.

[0885] For example, the multilink element 7200 may be included in a probe request frame and then transmitted. After receiving the probe request frame, the AP may verify the ML IE 7200 within the probe request frame. The AP may transmit a response message including critical update information of a specific link requested by the STA.

[0886] As an example, when the critical update request field 7210 is within the per-STA profile (x) element within the ML IE 7200, and when its value is equal to 1, the AP can recognize that the STA has requested critical update information. In addition, 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 change sequence field 7220 information received together. When there are updated details (that is, when there is changed information that the STA should update), the AP can send a compressed probe response frame including only the updated information.

[0887] According to an embodiment, the above information (e.g., the critical update request field 7210 and the change sequence field 7220) may be included in the ML IE at a common information level rather than a link-specific level, and the critical update information may also be requested together for all links rather than for a specific link. An exemplary multilink element related to this may refer to Fig.73 describe.

[0888] Fig.73 Another example of a multi-link element format is shown.

[0889] Reference Fig.73 , the critical update request field 7310 (ie, the value is set to 1) and the change sequence field 7320 may be included in a common information location within the ML IE 7300 rather than a link specific information location (eg, per STA profile (x)).

[0890] The STA may send a probe request frame including the ML IE 7300. Upon receiving this, the AP recognizes that the STA has requested all links carried by the STA itself, not a specific link, and then the AP may compare the change sequence field information sent by the STA with the current change sequence information of all links carried by the STA itself. When there are updated details (i.e., when there is changed information that the STA should update), the AP may send a compressed probe response frame including only the updated information of all links.

[0891] Fig.74 Another example of a multi-link element format is shown.

[0892] Reference Fig.74 , the MLIE 7400 may include a key update request field 7410 and a change sequence field 7420. Fig.73 Unlike the illustrated ML IE 7300, a critical update request field 7410 may be included in the multi-link control field. The STA may request critical update information of a link change through the ML IE 7400.

[0893] 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 proposed in this specification. In addition, 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.

[0894] According to an embodiment, although the IOM operation can be performed after establishing accurate operation negotiation between MLDs through the above-mentioned IOM signaling method, the IOM operation can also be performed through MLD implementation without any separate signaling process. This may mean that the IOM can operate through AP MLD implementation or non-AP MLD implementation without any negotiation between AP MLD and non-AP MLD.

[0895] Based on the above-described embodiments, although the AP MLD and the non-AP MLD may operate, the following limitations may occur when the MLD performs IOM operation without any separate signaling exchange.

[0896] 1) Restriction on request method: When information sharing between APs that do not support AP MLD, and when a STA has requested information on another link, a response cannot be made (or sent).

[0897] 2) Restriction on the unsolicited method: The AP can autonomously determine the STA that needs additional link information and can provide a separate message (eg, beacon interval, etc.) to the corresponding STA. Therefore, the STA cannot predict whether to receive the information.

[0898] When MLD implements IOM without any separate signaling method, the operation process can be simplified. However, the above-mentioned limitations may occur.

[0899] According to an embodiment, a method for requesting information related to multilink may be configured based on negotiation between the AP MLD and the non-AP MLD performed using the above-mentioned 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).

[0900] For example, during or after multi-link establishment, although the ST may receive information of the AP based on the details of the negotiation according to the negotiation between the AP MLD and the non-AP MLD, the STA may temporarily wish to request information of a specific AP or specific parameter information of the AP. In this case, when requesting information, the STA may include instructions about the information that the STA wishes to request in an "IOM Capability" element within a request frame (e.g., a probe request frame or a (re)association frame or a new frame, etc.), and may send the request frame. The AP may 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 the field within the IOM Capability element is omitted, the AP may provide information to the STA based on the details of a previous (or existing) negotiation.

[0901] 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 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. In addition, by including an instruction that the STA wants 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.

[0902] According to an embodiment, when the non-AP MLD and the AP MLD wish to change the details of the negotiation after completing the multi-link establishment, the non-AP MLD and the AP MLD may update the negotiation details between the MLDs through a separate message exchange.

[0903] Fig.75 is a flow chart describing the operation of a multi-link device.

[0904] Reference Fig.75 , in step S7510, the multi-link device (MLD) may send a request frame including an information field for requesting at least one element related to the second link.

[0905] According to an embodiment, a multi-link device (MLD) may send a request frame to a first access point (AP) of the multi-link device through a first station (STA), the request frame including an information field for requesting at least one element related to the second link.

[0906] For example, a multi-link device may be connected to an AP multi-link device via multiple links including a first link. A multi-link device may include multiple STAs associated with multiple links. For example, among multiple STAs, a first STA may be connected to the first link. In other words, the first STA may operate in the first link. In addition, the first STA may be connected to a first AP of the AP multi-link device via the first link.

[0907] For example, the plurality of links and the second link may be included within the 2.4 GHz, 5 GHz, and 6 GHz frequency bands.

[0908] For example, the request frame may include a probe request frame. As an example, an information field for requesting at least one element related to the second link may be included in a multilink element included in the probe request frame.

[0909] 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 bits of information. For example, the identifier of the first link and the identifier of the second link may be expressed by 4 bits.

[0910] According to an embodiment, a set of elements that can be requested by a request frame can be referred to as an element set. Therefore, all / complete elements included in an element set can mean all / complete elements that can be requested by a request frame. An element set can be configured differently based on a frame type. For example, an element set can be configured differently in a probe request frame and an association request frame.

[0911] For example, at least one element may be included in the element set specified for the second link. In other words, the multilink device may request some elements from the elements (or some elements) included in the element set specified for the second link.

[0912] As an example, the request frame may include 1-bit information regarding whether the at least one element is a partial set or a complete set of elements included in the specified element set.

[0913] Based on the 1-bit information being set to the first value, the multilink device may request at least one element as part of the elements included in the specified element set.Based on the 1-bit information being set to the second value, the multilink device may request at least one element as all the elements included in the specified element set.

[0914] In other words, by configuring the 1-bit information to have a first value (eg, 0), the multilink device may indicate a portion of the elements included in the element set specified by the request. Therefore, the 1-bit information included in the request frame may be set to the first value.

[0915] In addition, by configuring the 1-bit information as a second value (eg, 1), the multi-link device may indicate that all elements included in the element set specified by the request are being requested.

[0916] 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 wishes to receive to the AP multi-link device.

[0917] 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 an extended request element. As an example, the information for identifying at least one element may be included in a multilink element.

[0918] 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 of all link requests for operation in the AP multi-link device. The second field may include information for identifying elements only for the second link request.

[0919] In other words, the first field may include information (or ID) about an element that the multilink device requests in common for all links. The second field may include information (or ID) about an element that the multilink device requests only for the second link.

[0920] 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 a 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.

[0921] According to an embodiment, the second link may be distinguished from the plurality of links. When the second link is distinguished from the plurality of links, the multi-link device may send a request frame for requesting at least one element related to a link that is not currently connected to the multi-link device itself (i.e., the second link). The multi-link device may receive at least one element related to a link that is not currently connected to the multi-link device itself (i.e., the second link) through a 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.

[0922] According to an embodiment, the multi-link device may send a second request frame for requesting that the link connected to the first STA be switched 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.

[0923] The multi-link device may establish a connection between the first STA and the second AP of the AP multi-link device based on a process for switching the link 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, the first STA may establish a connection with the second AP through the second link based on the above process.

[0924] According to an embodiment, the second link may be included in a plurality of links. When the second link is included in a plurality of links, the multilink device may send a request frame for requesting an element related to a link currently connected to the multilink device's own link (i.e., the second link) through the first link. In other words, the multilink device may send a request frame for requesting at least one element related to another link (i.e., the second link) through the first link. The multilink device may receive at least one element related to a link (i.e., the second link) among the links currently connected to the multilink device through a response frame based on the request frame.

[0925] Fig.76 is a flow chart describing the operation of an AP multi-link device.

[0926] Reference Fig.76 In step S7610, the AP multi-link device (MLD) may 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) may 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.

[0927] According to an embodiment, the AP multi-link device may be connected to the multi-link device via multiple links. For example, the second link may be included in the multiple links. As another example, the second link may be distinguished from the multiple links.

[0928] For example, an AP multi-link device may be connected to a multi-link device via multiple links including a first link. The AP multi-link device may include multiple APs associated with multiple links. For example, among multiple APs, a first AP may be connected to the first link. In other words, the first AP may operate in the first link. In addition, the first AP may be connected to a first STA of the multi-link device via the first link.

[0929] For example, the plurality of links and the second link may be included within the 2.4 GHz, 5 GHz, and 6 GHz frequency bands.

[0930] For example, the request frame may include a probe request frame. As an example, an information field for requesting at least one element related to the second link may be included in a multilink element included in the probe request frame.

[0931] 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 bits of information. For example, the identifier of the first link and the identifier of the second link may be expressed by 4 bits.

[0932] According to an embodiment, a set of elements that can be requested by a request frame can be referred to as an element set. Therefore, all elements included in an element set can mean all elements that can be requested by a request frame. An element set can be configured differently based on a frame type. For example, an element set can be configured differently in a probe request frame and an association request frame.

[0933] For example, at least one element may be included in the element set specified for the second link. In other words, the AP multi-link device may receive a request frame for requesting some elements among the elements (or some elements) included in the element set specified for the second link.

[0934] As an example, the request frame may include 1-bit information regarding whether the at least one element is a partial set or a complete set of elements included in the specified element set.

[0935] Based on the 1-bit information being set to the first value, the AP multi-link device can verify that the request frame is a frame for requesting at least one element as part of the elements included in the specified element set. Therefore, the 1-bit information included in the request frame can be set to the first value.

[0936] Based on the 1-bit information being set to the second value, the AP multi-link device can verify that the request frame is a frame for requesting all elements included in the designated element set.

[0937] 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 AP multi-link device may verify the ID of at least one element that the multi-link device itself wishes to receive.

[0938] 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 an extended request element. As an example, the information for identifying at least one element may be included in a multilink element.

[0939] 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 of all link requests for operation in the AP multi-link device. The second field may include information for identifying elements only for the second link request.

[0940] In other words, the first field may include information (or ID) about an element that the multilink device requests in common for all links. The second field may include information (or ID) about an element that the multilink device requests only for the second link.

[0941] 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.

[0942] According to an embodiment, the second link may be distinguished from a plurality of links. When the second link is distinguished from a plurality of links, the AP multi-link device may receive a request frame for requesting at least one element related to a link that is not currently connected to the AP multi-link device itself (i.e., the second link). The AP multi-link device may send at least one element related to a link that is not currently connected to the AP multi-link device itself (i.e., the second link) through a 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.

[0943] According to an embodiment, the AP multi-link device may receive a second request frame for requesting that the link connected to the first STA be switched 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.

[0944] The second AP of the AP multi-link device can establish a connection with the first STA based on the process of switching the link connected to the first STA from the first link to the second link. For example, the second AP can operate in the second link. In addition, the first STA can also operate in the second link. In other words, based on the above process, the first STA can establish a connection with the first STA through the second link.

[0945] According to an embodiment, the second link may be included in a plurality of links. When the second link is included in a 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 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 AP multi-link device through a response frame based on the request frame.

[0946] The above technical features of this specification can be applied to various devices and methods. Figure 1 and / or Fig.19 Execute / support the above technical features of this specification. For example, the above technical features of this specification can only be applied to Figure 1 and / or Fig.19 For example, the above technical features of this specification can be based on Figure 1 The processing chip (114, 124) is implemented, or based on the processor (111, 121) and the memory (112, 122), or based on Fig.19 For example, the device of the present specification may include a processor and a memory operatively connected to the processor, wherein the processor may be configured to: send a request frame including an information field for requesting at least one element related to the second link to a first AP of the access point (AP) multi-link device through a first station (STA) included in the 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 receive a response frame from the first AP through the first STA based on the request frame, wherein the response frame includes the at least one element.

[0947] The technical features of the present specification can be implemented based on a computer-readable medium (CRM). For example, the CRM proposed in the present specification can be encoded as at least one computer program including instructions. When executed by at least one processor, the instructions can perform operations including the following steps: sending a request frame including an information field for requesting at least one element related to the second link to an access point (AP) multi-link device through a first station (STA) operating in the first link through a first station (STA) included in a multi-link device to a first AP of the access point (AP) multi-link device, wherein the information field includes information for identifying at least one element; and receiving a response frame from the first AP through the first STA based on the request frame, wherein the response frame includes at least one element. The instructions stored in the CRM of the present specification can be executed by at least one processor. The at least one processor related to the CRM of the present specification may be Figure 1 A processor (111, 121) or a processing chip (114, 124) or Fig.19 In addition, the CRM of this specification may be Figure 1 Memory (112,122) or Fig.19 memory (620) or a separate external memory / storage medium / disk, etc.

[0948] 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 wireless communications of devices supporting artificial intelligence (AI).

[0949] Artificial intelligence refers to the field of study regarding artificial intelligence or methods of creating artificial intelligence, while machine learning refers to the field of study regarding methods of defining and solving various problems in the field of artificial intelligence. Machine learning is also defined as algorithms that improve the performance of operations through stable experience of operations.

[0950] An artificial neural network (ANN) is a model used in machine learning and may refer to an overall problem-solving model that includes artificial neurons (nodes) that form a network by combining synapses. An artificial neural network may be defined by the connection pattern between neurons in different layers, a learning process that updates model parameters, and an activation function that generates an output value.

[0951] The artificial neural network may include an input layer, an output layer, and optionally one or more hidden layers. Each layer includes one or more neurons, and the artificial neural network may include synapses connecting neurons. In the artificial neural network, each neuron may output a function value of an activation function of an input signal, a weight, and a bias input through a synapse.

[0952] Model parameters refer to parameters determined by learning and include weights of synaptic connections and biases of neurons. Hyperparameters refer to parameters set in a machine learning algorithm before learning and include learning rate, number of iterations, mini-batch size, and initialization function.

[0953] Learning an artificial neural network can be aimed at determining model parameters for minimizing a loss function. The loss function can be used as an index for determining the optimized model parameters during learning an artificial neural network.

[0954] Machine learning can be categorized into supervised learning, unsupervised learning, and reinforcement learning.

[0955] Supervised learning refers to a method of training an artificial neural network when labels are given for training data, where the labels may indicate the correct answer (or result value) that the artificial neural network needs to infer when the training data is input to the artificial neural network. Unsupervised learning may refer to a method of training an artificial neural network when no labels are given for training data. Reinforcement learning may refer to a training method of an agent defined in a training environment to select actions or action sequences to maximize the cumulative reward in each state.

[0956] Machine learning implemented using a deep neural network (DNN) including multiple hidden layers in an artificial neural network is called deep learning, and deep learning is a part of machine learning. Hereinafter, machine learning is explained as including deep learning.

[0957] The above technical features can be applied to wireless communication of robots.

[0958] A robot may refer to a machine that automatically processes or operates a given task with its own capabilities. Specifically, a robot that has the function of recognizing the environment and autonomously making judgments to perform operations may be referred to as an intelligent robot.

[0959] Robots can be classified into industrial, medical, household, military robots, etc. according to their uses or fields. Robots can include actuators or drives, which include motors to perform various physical operations (e.g., move robot joints). In addition, mobile robots can include wheels, brakes, propellers, etc. in the drive to travel on the ground or fly in the air through the drive.

[0960] The above technical features can be applied to devices that support extended reality.

[0961] Extended reality refers collectively 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.

[0962] MR technology is similar to AR technology in that real objects and virtual objects are displayed together. However, in AR technology, virtual objects are used as a supplement to real objects, while in MR technology, virtual objects and real objects are used as equal.

[0963] XR technology may be applied to head mounted displays (HMDs), heads up displays (HUDs), mobile phones, tablet PCs, laptop computers, desktop computers, TVs, digital signage, etc. Devices to which XR technology is applied may be referred to as XR devices.

[0964] The claims described in this specification can be combined in various ways. For example, the technical features of the method claims of this specification can be combined to be implemented as a device, and the technical features of the device claims of this specification can be combined to be implemented by a method. In addition, the technical features of the method claims of this specification and the technical features of the device claims can be combined to be implemented as a device, and the technical features of the method claims of this specification and the technical features of the device claims can be combined to be implemented by a method.

Claims

1. A method in a wireless local area network (WLAN) system, the method comprising the following steps: A first station STA included in the multi-link device MLD sends a probe request frame for requesting at least one element related to a second link to a first AP of the access point AP multi-link device, wherein the first STA operates in the first link, and wherein the probe request frame includes 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 STA included in the MLD from the first AP, wherein the response frame includes information related to simultaneous transmission and reception of STR capability information between links.

2. The method according to claim 1, wherein: The probe request frame includes an information field including a first field and a second field, The first field includes information for identifying elements of all link requests for operation in the AP multi-link device, and The second field includes information for identifying an element requested only for the second link.

3. The method according to claim 1, wherein: The at least one element is included in a set of elements specified for the second link.

4. The method according to claim 1, wherein: The 1-bit information is adjacent to the ID information.

5. A method in a wireless local area network (WLAN) system, the method comprising the following steps: receiving, by a first AP included in an access point AP multi-link device MLD, a probe request frame for requesting at least one element related to a second link from a first station STA of the multi-link device, wherein the first AP operates in the first link, and wherein the probe request frame includes 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, the first AP included in the AP MLD sends a response frame to the first STA, wherein the response frame includes information related to simultaneous transmission and reception of 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 multi-link device MLD in a wireless local area network WLAN system, the MLD comprising: A first station STA operating in a first link; a second STA operating in a second link; a transceiver for sending and / or receiving wireless signals; as well as 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 to a first AP of an access point (AP) multi-link device through the first STA included in the MLD, wherein the probe request frame includes 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 request frame, a response frame is received from the first AP through the first STA, wherein the response frame includes information related to simultaneous transmission and reception of 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.

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