Method and apparatus for acquiring information regarding inter-MLD links in a wireless LAN system

Abstract

A method and apparatus for acquiring information about inter-MLD links in a wireless LAN system are proposed. Specifically, a receiving MLD transmits a probe request frame to a transmitting MLD via a first link. The receiving MLD receives a probe response frame from the transmitting MLD via the first link. The transmitting MLD includes a first transmitting STA operating on the first link, a second transmitting STA operating on the second link, and a third transmitting STA operating on the third link. The receiving MLD includes a first receiving STA operating on the first link. If the first receiving STA requests information about the second and third links, the probe request frame includes link identifiers for the second and third links. If the first receiving STA requests information about all links, the probe request frame does not include link identifiers for all links.

Description

[Technical field]

[0001] The present specification relates to multi-link operation in a wireless LAN system, and more particularly, to a method and apparatus for obtaining information on inter-MLD links. [Background technology]

[0002] WLAN (wireless local area network) has been improved in various ways, for example, the IEEE 802.11ax standard proposed an improved communication environment using OFDMA (orthogonal frequency division multiple access) and DL MU MIMO (downlink multi-user multiple input, multiple output) technologies.

[0003] This specification proposes technical features that can be utilized in a new communication standard. For example, the new communication standard is the Extreme high throughput (EHT) standard that has been recently discussed. The EHT standard can use newly proposed bandwidth increases, improved PHY layer protocol data unit (PPDU) structure, improved sequences, and Hybrid automatic repeat request (HARQ) techniques. The EHT standard can be referred to as the IEEE 802.11be standard.

[0004] New WLAN standards will use an increased number of spatial streams, which requires improved signaling techniques within the WLAN system to properly use the increased number of spatial streams. Summary of the Invention [Problem to be solved by the invention]

[0005] This specification proposes a method and apparatus for acquiring information on inter-MLD links in a wireless LAN system. [Means for solving the problem]

[0006] In one embodiment of the present specification, a method for obtaining information on inter-MLD links is proposed.

[0007] This embodiment can be executed in a network environment supporting a next-generation wireless LAN system (IEEE 802.11be or EHT wireless LAN system). The next-generation wireless LAN system is an improved wireless LAN system of the 802.11ax system and can meet backward compatibility with the 802.11ax system.

[0008] This embodiment proposes a method and apparatus for a STA of a receiving MLD to request information on all or some of the links of a transmitting MLD in MLD communication. The transmitting MLD may be an AP MLD, and the receiving MLD may be a non-AP MLD.

[0009] A receiving MLD (Multi-link Device) transmits a probe request frame to a transmitting MLD via a first link.

[0010] The receiving MLD receives a probe response frame from the transmitting MLD via the first link.

[0011] As an example, the transmitting MLD includes a first transmitting STA (station) operating in the first link, a second transmitting STA operating in the second link, and a third transmitting STA operating in the third link. The receiving MLD includes a first receiving STA operating in the first link. The receiving MLD may further include a second receiving STA operating in the second link, and a third receiving STA operating in the third link.

[0012] When the first receiving STA requests information on the second and third links, the probe request frame includes link identifiers for the second and third links. That is, when the first receiving STA desires to receive only information on a specific link from the first transmitting STA, the probe request frame can include the link identifier for the specific link to indicate the required information. Effect of the Invention

[0013] According to the embodiments proposed in this specification, when a receiving STA requests information for all links, there is no need to include identifiers for all links (by omitting or removing identifiers for all links), which has the effect of reducing the overhead of the probe request frame. [Brief description of the drawings]

[0014] [Figure 1] 1 illustrates an example of a transmitting device and / or a receiving device of the present specification. [Diagram 2] 1 is a conceptual diagram showing the structure of a wireless LAN (WLAN). [Diagram 3] 1 is a diagram illustrating a typical link setup process. [Figure 4] 1 is a diagram showing an example of a PPDU used in the IEEE standard. [Diagram 5] The operation related to UL-MU is shown. [Figure 6] 1 shows an example of a trigger frame. [Figure 7] 1 shows an example of a common information field of a trigger frame. [Figure 8] An example of subfields included in a per user information field is shown below. [Figure 9] Explain the technical features of UORA technology. [Figure 10] 1 shows an example of a PPDU used in this specification. [Figure 11] 1 shows a variation of the transmitting device and / or the receiving device of the present specification. [Figure 12] 1 shows an example of a non-AP MLD structure. [Figure 13] 1 shows an example in which an AP MLD and a non-AP MLD are connected via a link setup process. [Figure 14] Here is an example where a link is changed or reconnected. [Figure 15] Here is a specific example of how a link is changed or reconnected. [Figure 16] 4 shows the operation of AP MLD and non-AP MLD for link change or reconnection. [Figure 17] 4 shows the operation of AP MLD and non-AP MLD for link change or reconnection. [Figure 18] 4 shows the operation of AP MLD and non-AP MLD for link change or reconnection. [Figure 19] 4 shows the operation of AP MLD and non-AP MLD for link change or reconnection. [Figure 20] 13 shows the operation of non-AP MLD to request information about other APs. [Figure 21] A specific example of STA ratio per Link is shown below. [Figure 22] 4 shows the operation of AP MLD and non-AP MLD for link change or reconnection. [Figure 23] 4 shows the operation of AP MLD and non-AP MLD for link change or reconnection. [Figure 24] 4 shows the operation of AP MLD and non-AP MLD for link change or reconnection. [Diagram 25] An example of the Request IE format is shown below. [Figure 26] An example of the Extended Request IE format is shown below. [Figure 27] An example of the PV 1 Probe Response Option element format is shown below. [Figure 28] An example of the ML element format defined in 802.11be is shown below. [Figure 29] Probe Request variant Indicates the Per-STA Profile subelement of the Multi-Link element. [Diagram 30] 11 is a flow diagram showing a procedure in which a transmitting MLD according to the present embodiment provides information on an AP included in the transmitting MLD to a receiving MLD based on a probe response frame. FIG. [Diagram 31] 11 is a flow diagram showing a procedure in which a receiving MLD according to the present embodiment requests information on an AP included in the transmitting MLD based on a probe request frame. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] As used herein, "A or B" can mean "only A," "only B," or "both A and B." Also, as used herein, "A or B" can be interpreted as "A and / or B." For example, as used herein, "A, B or C" can mean "only A," "only B," "only C," or "any combination of A, B and C."

[0016] As used herein, a slash ( / ) or a comma can mean "and / or." For example, "A / B" can mean "A and / or B." Thus, "A / B" can mean "only A," "only B," or "both A and B." For example, "A, B, C" can mean "A, B, or C."

[0017] In this specification, "at least one of A and B" can mean "only A," "only B," or "both A and B." In addition, in this specification, the expressions "at least one of A or B" and "at least one of A and / or B" can be interpreted similarly to "at least one of A and B."

[0018] In addition, in this specification, "at least one of A, B and C" can 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" can mean "at least one of A, B and C."

[0019] In addition, parentheses used in this specification may mean "for example." Specifically, when "control information (PDCCH)" is used, "PDCCH" is proposed as an example of "control information." In addition, "control information" in this specification is not limited to "PDCCH," and "PDDCH" is proposed as an example of "control information." In addition, when "control information (i.e., PDCCH)" is used, "PDCCH" is proposed as an example of "control information."

[0020] In this specification, technical features individually described in one drawing may be embodied individually or simultaneously.

[0021] The following example of the present specification applies to various wireless communication systems. For example, the following example of the present specification applies to a wireless local area network (WLAN) system. For example, the present specification applies to the IEEE 802.11a / g / n / ac standard and the IEEE 802.11ax standard. The present specification also applies to the newly proposed EHT standard or IEEE 802.11be standard. The present specification also applies to a new WLAN standard that is an enhancement of the EHT standard or IEEE 802.11be. The present specification also applies to a mobile communication system. For example, the present specification applies to a mobile communication system based on LTE (Long Term Evolution) based on the 3GPP (registered trademark) (3rd Generation Partnership Project) standard and its evolution. The present specification also applies to a 5GNR standard communication system based on the 3GPP standard.

[0022] In the following, technical features to which this specification is applied will be described in order to explain the technical features of this specification.

[0023] FIG. 1 shows an example of a transmitting device and / or a receiving device according to the present specification.

[0024] The example of FIG. 1 may implement various technical features described below. FIG. 1 relates to at least one STA (station). For example, the STA (110, 120) in this specification may be referred to by various names such as a mobile terminal, a wireless device, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), a mobile subscriber unit, or simply a user. The STA (110, 120) in this specification may be referred to by various names such as a network, a base station, a Node-B, an access point (AP), a repeater, a router, a relay, etc. The STA (110, 120) in this specification may be referred to by various names such as a receiving device, a transmitting device, a receiving STA, a transmitting STA, a receiving device, a transmitting device, etc.

[0025] For example, the STAs (110, 120) can perform an AP (Access Point) role or a non-AP role. That is, the STAs (110, 120) in this specification can perform the functions of an AP and / or a non-AP. In this specification, an AP can also be referred to as an AP STA.

[0026] The STAs (110, 120) of this specification can support various communication standards other than the IEEE 802.11 standard. For example, communication standards related to the 3GPP standard (e.g., LTE, LTE-A, 5GNR standard) can be supported. The STAs of this specification are implemented in various devices such as mobile phones, vehicles, and personal computers. The STAs of this specification can support communication for various communication services such as voice calls, video calls, data communications, self-driving, autonomous driving, etc.

[0027] As used herein, the STAs (110, 120) may include a medium access control (MAC) and physical layer interface to the wireless medium as defined by the IEEE 802.11 standard.

[0028] The STAs (110, 120) will be described below based on FIG. 1(a).

[0029] The first STA 110 includes a processor 111, a memory 112, and a transceiver 113. The depicted processor, memory, and transceiver may each be implemented as a separate chip, or at least two or more of the blocks / functions may be implemented via a single chip.

[0030] The transceiver (113) of the first STA performs signal transmission and reception operations, specifically, it can transmit and receive IEEE 802.11 packets (e.g., IEEE 802.11a / b / g / n / ac / ax / be, etc.).

[0031] For example, the first STA (110) can perform the intended operations of the AP. For example, the processor (111) of the AP can receive signals via the transceiver (113), process the received signals, generate transmission signals, and perform control for signal transmission. The memory (112) of the AP can store signals received via the transceiver (113) (i.e., received signals) and can store signals transmitted via the transceiver (i.e., transmitted signals).

[0032] For example, the second STA (120) can perform the intended operation of a non-AP STA. For example, the non-AP transceiver (123) can transmit and receive signals. Specifically, it can transmit and receive IEEE 802.11 packets (e.g., IEEE 802.11a / b / g / n / ac / ax / be, etc.).

[0033] For example, the processor (121) of the Non-AP STA can receive signals via the transceiver (123), process the received signals, generate transmission signals, and execute control for signal transmission. The memory (122) of the Non-AP STA can store signals received via the transceiver (123) (i.e., received signals) and can store signals transmitted via the transceiver (i.e., transmitted signals).

[0034] For example, in the following specification, the operation of the device indicated as AP is executed in the first STA (110) or the second STA (120). For example, when the first STA (110) is an AP, the operation of the device indicated as AP is controlled by the processor (111) of the first STA (110), and related signals are transmitted or received via a transceiver (113) controlled by the processor (111) of the first STA (110). In addition, control information related to the operation of the AP and transmitted / received signals of the AP are stored in the memory (112) of the first STA (110). In addition, when the second STA (110) is an AP, the operation of the device indicated as AP is controlled by the processor (121) of the second STA (120), and related signals are transmitted or received via a transceiver (123) controlled by the processor (121) of the second STA (120). In addition, control information related to the operation of the AP and transmitted / received signals of the AP are stored in the memory (122) of the second STA (110).

[0035] For example, in the following specification, the operation of the device indicated as non-AP (or User-STA) is executed 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 non-AP is controlled by the processor (121) of the second STA (120), and related signals are transmitted or received via the transceiver (123) controlled by the processor (121) of the second STA (120). In addition, control information related to the operation of the non-AP and the transmission / reception signals of the AP are 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 non-AP is controlled by the processor (111) of the first STA (110), and related signals are transmitted or received via the transceiver (113) controlled by the processor (111) of the first STA (120). In addition, control information related to the operation of the non-AP and transmission / reception signals of the AP are stored in the memory (112) of the first STA (110).

[0036] In the following specification, devices called (transmitting / receiving) STA, first STA, second STA, STA1, STA2, AP, first AP, second AP, AP1, AP2, (transmitting / receiving) Terminal, (transmitting / receiving) Device, (transmitting / receiving) apparatus, network, etc. refer to the STAs (110, 120) in Fig. 1. For example, devices indicated as (transmitting / receiving) STA, first STA, second STA, STA1, STA2, AP, first AP, second AP, AP1, AP2, (transmitting / receiving) Terminal, (transmitting / receiving) Device, (transmitting / receiving) apparatus, network, etc. without specific reference numerals also refer to the STAs (110, 120) in Fig. 1. For example, in the following example, the operations of various STAs transmitting and receiving signals (e.g., PPPDUs) may be performed in the transceivers (113, 123) in Fig. 1. In the following example, various STAs may generate transmission / reception signals or perform data processing or calculations in advance for transmission / reception signals in the processors (111, 121) of Fig. 1. For example, an example of an operation for generating transmission / reception signals or performing data processing or calculations in advance for transmission / reception signals may include: 1) an operation for determining / obtaining / configuring / calculating / decoding / encoding bit information of subfields (SIG, STF, LTF, Data) included in a PPDU; 2) an operation for determining / configuring / acquiring time resources and frequency resources (e.g., subcarrier resources) used for the subfields (SIG, STF, LTF, Data) included in a PPDU; 3) an operation for determining / configuring / acquiring specific sequences (e.g., pilot sequences, STF / LTF sequences, extra sequences applied to SIGs) used for the subfields (SIG, STF, LTF, Data) included in a PPDU; 4) an operation for power control and / or power saving applied to the STA; and 5) an operation related to determining / obtaining / configuring / calculating / decoding / encoding an ACK signal.In addition, in the following example, various information (e.g., information related to fields / subfields / control fields / parameters / power, etc.) used by various STAs to determine / acquire / configure / calculate / decode / encode transmitted / received signals is stored in memories (112, 122) of FIG. 1.

[0037] The above-mentioned device / STA in Fig. 1(a) is modified as shown in Fig. 1(b). The STA (110, 120) of this specification will be described based on Fig. 1(b) below.

[0038] For example, the transceivers (113, 123) shown in FIG. 1(b) may perform the same functions as the transceivers shown in FIG. 1(a) described above. For example, the processing chips (114, 124) shown in FIG. 1(b) may include processors (111, 121) and memories (112, 122). The processors (111, 121) and memories (112, 122) shown in FIG. 1(b) may perform the same functions as the processors (111, 121) and memories (112, 122) shown in FIG. 1(a) described above.

[0039] In the following description, a mobile terminal, a wireless device, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), a mobile subscriber unit, a user, a user STA, a network, a base station, a Node-B, an access point (AP), a repeater, a router, a relay, a receiving device, a transmitting device, a receiving STA, a transmitting STA, a receiving device, a transmitting device, a receiving apparatus, and / or a transmitting apparatus may refer to the STA (110, 120) shown in FIG. 1(a) / (b) or the processing chip (114, 124) shown in FIG. 1(b). That is, the technical features of this specification may be performed in the STA (110, 120) shown in FIG. 1(a) / (b) or may be performed only in the processing chip (114, 124) shown in FIG. 1(b). For example, the technical feature of the transmitting STA transmitting a control signal can be understood as the technical feature of the control signal generated in the processor (111, 121) shown in Fig. 1(a) / (b) being transmitted via the transceiver (113, 123) shown in Fig. 1(a) / (b). Alternatively, the technical feature of the transmitting STA transmitting a control signal can be understood as the technical feature of the control signal to be transmitted to the transceiver (113, 123) being generated in the processing chip (114, 124) shown in Fig. 1(b).

[0040] For example, the technical feature of the receiving STA receiving the control signal can be understood as the technical feature of the control signal being received by the transceiver (113, 123) shown in Fig. 1(a). 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 transceiver (113, 123) shown in Fig. 1(a) being acquired by the processor (111, 121) shown in Fig. 1(a). 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 transceiver (113, 123) shown in Fig. 1(b) being acquired by the processing chip (114, 124) shown in Fig. 1(b).

[0041] 1(b), software code (115, 125) is included within the memories (112, 122). The software code (115, 125) includes instructions that control the operation of the processors (111, 121). The software code (115, 125) may be included in a variety of programming languages.

[0042] The processors (111, 121) or processing chips (114, 124) shown in FIG. 1 may include an application-specific integrated circuit (ASIC), other chipsets, logic circuits, and / or data processing devices. The processors are application processors (APs). For example, the processors (111, 121) or processing chips (114, 124) shown in FIG. 1 may include at least one of a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), and a modem (modulator and demodulator). For example, the processors (111, 121) or processing chips (114, 124) shown in FIG. 1 may include a SNAPDRAGON 3.0 GHz processor manufactured by Qualcomm®. TMEXYNOS series processors, manufactured by Samsung TM Series processors, A-series processors manufactured by Apple®, HELIO manufactured by MediaTek® TM ATOM series processors, manufactured by INTEL® TM It is a series processor or an enhanced version of the series processor.

[0043] In this specification, an uplink refers to a link for communication from a non-AP STA to an AP STA, and an uplink PPDU / packet / signal, etc. are transmitted via the uplink. Also, in this specification, a downlink refers to a link for communication from an AP STA to a non-AP STA, and a downlink PPDU / packet / signal, etc. are transmitted via the downlink.

[0044] FIG. 2 is a conceptual diagram showing the structure of a wireless LAN (WLAN).

[0045] The top part of Figure 2 shows the structure of an IEEE (Institute of electrical and eletronic engineers) 802.11 infrastructure basic service set (BSS).

[0046] Referring to the top of FIG. 2, the wireless LAN system can include one or more infrastructure BSSs (200, 205) (hereinafter, BSS). The BSSs (200, 205) are a set of APs and STAs, such as an access point (AP, 225) and a station (STA1, 200-1), that can properly synchronize and communicate with each other, and are not a concept that refers to a specific area. The BSS (205) can include one AP (230) and one or more STAs (205-1, 205-2) that can be associated with it.

[0047] The BSS can include at least one STA, APs (225, 230) that provide a distribution service, and a distribution system (DS, 210) that connects multiple APs.

[0048] The distribution system (210) can implement an extended service set (ESS, 240) by connecting multiple BSSs (200, 205). The term ESS (240) is used to indicate a network formed by connecting one or multiple APs via the distribution system (210). APs included in one ESS (240) have the same service set identification (SSID).

[0049] The portal (220) can act as a bridge to connect a wireless LAN network (IEEE 802.11) to other networks (eg, 802.X).

[0050] In the BSS shown in the upper part of Figure 2, a network between APs (225, 230) and a network between APs (225, 230) and STAs (200-1, 205-1, 205-2) are implemented. However, it is also possible to set up a network between STAs without APs (225, 230) and communicate with each other. A network that sets up a network between STAs without APs (225, 230) and communicates with each other is defined as an Ad-Hoc network or an independent basic service set (IBSS).

[0051] The lower part of Figure 2 is a conceptual diagram showing the IBSS.

[0052] Referring to the bottom of Figure 2, an IBSS is a BSS that operates in an ad-hoc mode. Since an IBSS does not include an AP, there is no centralized management entity that performs management functions. That is, in an IBSS, STAs (250-1, 250-2, 250-3, 255-4, 255-5) are managed in a distributed manner. In an IBSS, all STAs (250-1, 250-2, 250-3, 255-4, 255-5) are mobile STAs, and are not allowed to connect to a distribution system, forming a self-contained network.

[0053] FIG. 3 is a diagram illustrating a typical link setup process.

[0054] In the illustrated step S310, the STA can perform a network discovery operation. The network discovery operation can include a scanning operation of the STA. That is, in order for the STA to access a network, it needs to find a joinable network. The STA needs to identify a compatible network before joining a wireless network, and the process of identifying networks that exist in a specific area is called scanning. There are two scanning methods: active scanning and passive scanning.

[0055] FIG. 3 shows an example of a network discovery operation including an active scan process. In active scan, a STA performing scanning moves channels and transmits a probe request frame to search for APs in the vicinity, and waits for a response to the probe request frame. A responder transmits a probe response frame to the STA that transmitted the probe request frame in response to the probe request frame. Here, the responder is the STA that transmitted a beacon frame last in the BSS of the channel being scanned. In the BSS, the AP transmits a beacon frame, so the AP becomes the responder, and in the IBSS, the STA in the IBSS returns and transmits a beacon frame, so the responder is not constant. For example, a STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 can store BSS-related information included in the received probe response frame, move to the next channel (e.g., channel 2), and perform scanning in the same manner (i.e., probe request / response transmission / reception on channel 2).

[0056] Although not shown as an example in FIG. 3, the scanning operation may be performed by a passport scan method. A STA performing scanning based on passport scan can wait for a beacon frame while moving between channels. A beacon frame is one of management frames in IEEE 802.11, and is periodically transmitted to inform a scanning STA of the presence of a wireless network and to allow the scanning STA to find and join the wireless network. In a BSS, an AP periodically transmits a beacon frame, and in an IBSS, a STA in the IBSS returns and transmits a beacon frame. When a scanning STA receives a beacon frame, it stores information about the BSS included in the beacon frame, and moves to another channel while recording beacon frame information in each channel. A STA receiving a beacon frame can store BSS-related information included in the received beacon frame, move to the next channel, and perform scanning in the next channel in the same manner.

[0057] The STA that has discovered the network can perform an authentication process through step S320. This authentication process is called a first authentication process to clearly distinguish it from the security setting operation in step S340 described below. The authentication process in S320 may include a process in which the STA transmits an authentication request frame to the AP, and in response, the AP transmits an authentication response frame to the STA. The authentication frame used in the authentication request / response corresponds to a management frame.

[0058] The authentication frame can include information on the authentication algorithm number, authentication transaction sequence number, status code, challenge text, Robust Security Network (RSN), Finite Cyclic Group, etc.

[0059] The STA can send an authentication request frame to the AP. The AP can determine whether to allow authentication for the STA based on the information contained in the received authentication request frame. The AP can provide the STA with the result of the authentication process via an authentication response frame.

[0060] A successfully authenticated STA can perform an association process based on step S330. The association process includes a process in which the STA transmits an association request frame to the AP, and in response, the AP transmits an association response frame to the STA. For example, the association request frame can include information related to various capabilities, such as a beacon listen interval, a service set identifier (SSID), supported rates, supported channels, an RSN, a mobility domain, supported operating classes, a Traffic Indication Map Broadcast request, and information on interworking service capabilities. For example, the connection response frame may include information related to various capabilities, a status code, an association ID (AID), supported rates, an Enhanced Distributed Channel Access (EDCA) parameter set, a Received Channel Power Indicator (RCPI), a Received Signal to Noise Indicator (RSNI), a mobility domain, a timeout interval (association comeback time), overlapping BSS scan parameters, a TIM broadcast response, a QoS map, and the like.

[0061] Thereafter, the STA may perform a security setup process in step S340. The security setup process in step S340 may include, for example, a private key setup process via a four-way handshake using an Extesible Authentication Protocol over LAN (EAPOL) frame.

[0062] FIG. 4 is a diagram showing an example of a PPDU used in the IEEE standard.

[0063] As shown, various types of PPDUs (PHY protocol data units) are used in standards such as IEEEa / g / n / ac. Specifically, the LTF and STF fields contain training signals, SIG-A and SIG-B contain control information for the receiving station, and the data field contains user data corresponding to the PSDU (MAC PDU / Aggregated MAC PDU).

[0064] Also, Figure 4 includes an example of an HE PPDU of the IEEE 802.11ax standard. The HE PPDU in Figure 4 is an example of a PPDU for multiple users, and HE-SIG-B is included only for multiple users, and the corresponding HE-SIG-B is omitted in a PPDU for a single user.

[0065] As shown, an HE-PPDU for a Multiple User (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 (or MAC payload), and a Packet Extension (PE) field. Each field is transmitted during the indicated time interval (i.e., 4 or 8 μs, etc.).

[0066] The resource unit (RU) used in the PPDU is described as follows. The resource unit can include multiple subcarriers (or tones). The resource unit is used when transmitting signals to multiple STAs based on OFDMA technology. The resource unit is also defined when transmitting a signal to one STA. The resource unit is used for STF, LTF, data field, etc.

[0067] The RU described in this specification is used for UL (Uplink) communication and DL (Downlink) communication. For example, when UL-MU communication solicited by a Trigger frame is performed, a transmitting STA (e.g., AP) can assign a first RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to a first STA and a second RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to a second STA through the Trigger frame. Thereafter, the first STA can transmit a first Trigger-based PPDU based on the first RU, and the second STA can transmit a second Trigger-based PPDU based on the second RU. The first and second Trigger-based PPDUs are transmitted to the AP in the same time period.

[0068] For example, when a DL MU PPDU is configured, the transmitting STA (e.g., AP) can assign a first RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to the first STA and a second RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to the second STA. That is, the transmitting STA (e.g., AP) can transmit the HE-STF, HE-LTF, and Data fields for the first STA via the first RU and the HE-STF, HE-LTF, and Data fields for the second STA via the second RU in one MU PPDU.

[0069] 5 shows the operation related to the UL-MU. As shown, a transmitting STA (e.g., AP) can perform channel connection through contending (i.e., Backoff operation) and transmit a Trigger frame 1030. That is, the transmitting STA (e.g., AP) can transmit a PPDU including a Trigger frame 1330. If a PPDU including a Trigger frame is received, a TB (trigger-based) PPDU is transmitted after a delay of SIFS.

[0070] The TB PPDUs 1041 and 1042 are transmitted during the same time period, and are transmitted from multiple STAs (eg, User STAs) whose AIDs are indicated in the Trigger frame 1030. The ACK frame 1050 for the TB PPDU is implemented in various ways.

[0071] Specific features of the trigger frame are described with reference to Figures 6 to 8. When UL-MU communication is used, Orthogonal Frequency Division Multiple Access (OFDMA) technology or MU MIMO technology is used, or OFDMA and MU MIMO technology are used simultaneously.

[0072] An example of a trigger frame is shown in Fig. 6. The trigger frame in Fig. 6 allocates resources for uplink MU transmission (Uplink Multiple-User transmission) and is transmitted, for example, from an AP. The trigger frame is composed of a MAC frame and is included in a PPDU.

[0073] Each of the fields shown in Figure 6 may be omitted, other fields may be added, and the length of each of the fields may vary differently than shown.

[0074] The frame control field 1110 in FIG. 6 includes information regarding the version of the MAC protocol and other additional control information, and the duration field 1120 includes information regarding time information for NAV setting and an STA identifier (e.g., AID).

[0075] Also, the RA field 1130 includes address information of the STA receiving the trigger frame, and can be omitted if necessary. The TA field 1140 includes address information of the STA (e.g., AP) transmitting the trigger frame, and the common information field 1150 includes common control information applied to the receiving STA receiving the trigger frame. For example, a field indicating the length of the L-SIG field of the up PPDU transmitted corresponding to the trigger frame and information controlling the contents of the SIG-A field (i.e., the HE-SIG-A field) of the up PPDU transmitted corresponding to the trigger frame are included. Also, the common control information includes information regarding the length of the CP of the up PPDU transmitted corresponding to the trigger frame and information regarding the length of the LTF field.

[0076] In addition, it is preferable to include per user information fields (1160#1 to 1160#N) corresponding to the number of receiving STAs that receive the trigger frame in Fig. 6. The per user information fields may also be called "assignment fields."

[0077] The trigger frame of FIG. 6 may also include a padding field 1170 and a frame check sequence field 1180.

[0078] As shown in FIG. 6, each of the per user information fields (1160#1 through 1160#N) may again include multiple subfields.

[0079] Figure 7 shows an example of a common information field of a trigger frame. Some of the subfields in Figure 7 can be omitted and others can be added. Also, the length of each of the subfields shown can vary.

[0080] The indicated length field 1210 has the same value as the length field of the L-SIG field of the up PPDU transmitted corresponding to the trigger frame, and the length field of the L-SIG field of the up PPDU indicates the length of the up PPDU. As a result, the length field 1210 of the trigger frame is used to indicate the length of the corresponding uplink PPDU.

[0081] In addition, the cascade indicator field 1220 indicates whether or not cascade operation is performed. Cascade operation means that both downlink MU transmission and uplink MU transmission are performed within the same TXOP. In other words, it means that after downlink MU transmission is performed, uplink MU transmission is performed after a previously set time (e.g., SIFS). In cascade operation, there can be only one transmitter (e.g., AP) performing downlink communication, and multiple transmitters (e.g., non-AP) performing uplink communication.

[0082] The CS request field 1230 indicates whether the receiving device that received the trigger frame needs to take into account the state of the wireless medium, NAV, etc., when transmitting the corresponding uplink PPDU.

[0083] The HE-SIG-A information field 1240 includes information that controls the content of the SIG-A field (ie, the HE-SIG-A field) of the up PPDU transmitted in response to the trigger frame.

[0084] The CP and LTF type field 1250 may include information about the LTF length and CP length of the up PPDU transmitted corresponding to the trigger frame. The trigger type field 1060 may indicate the purpose for which the trigger frame is used, such as a normal trigger, a trigger for beamforming, a request for Block Ack / NACK, etc.

[0085] In this specification, the trigger type field 1260 of the trigger frame may be assumed to indicate a Basic type trigger frame for normal triggering, for example, a Basic type trigger frame may be referred to as a Basic trigger frame.

[0086] Figure 8 shows an example of subfields included in a per user information field. The user information field 1300 in Figure 8 can be understood as any one of the individual user information fields (1160#1 to 1160#N) mentioned in Figure 6. Some of the subfields included in the user information field 1300 in Figure 8 can be omitted and other subfields can be added. Also, the length of each of the subfields shown can be modified.

[0087] The User Identifier field 1310 in FIG. 8 indicates an identifier of the STA (i.e., the receiving STA) corresponding to the per user information, and an example of the identifier is all or part of the AID (association identifier) ​​value of the receiving STA.

[0088] Also included is an RU Allocation field 1320. That is, when a receiving STA identified by the user identifier field 1310 transmits a TB PPDU in response to the trigger frame, the TB PPDU is transmitted via an RU indicated by the RU allocation field 1320.

[0089] 8 may include a coding type field 1330. The coding type field 1330 may indicate a coding type of the TB PPDU. For example, if BCC coding is applied to the TB PPDU, the coding type field 1330 is set to '1', and if LDPC coding is applied, the coding type field 1330 is set to '0'.

[0090] 8 may include an MCS field 1340. The MCS field 1340 may indicate an MCS technique applied to the TB PPDU. For example, if BCC coding is applied to the TB PPDU, the coding type field 1330 is set to '1', and if LDPC coding is applied, the coding type field 1330 is set to '0'.

[0091] The following describes UORA (UL OFDMA-based Random Access) technology.

[0092] Figure 9 illustrates the technical features of the UORA technology.

[0093] A transmitting STA (e.g., AP) can allocate 6 RU resources through a trigger frame as shown in Fig. 9. Specifically, the AP can allocate 1 RU resource (AID 0, RU 1), 2 RU resource (AID 0, RU 2), 3 RU resource (AID 0, RU 3), 4 RU resource (AID 2045, RU 4), ​​5 RU resource (AID 2045, RU 5), and 6 RU resource (AID 3, RU 6). Information on AID 0, AID 3, or AID 2045 is included, for example, in the user identification field 1310 in Fig. 8. Information on RU 1 to RU 6 is included, for example, in the RU allocation field 1320 in Fig. 8. AID=0 means UORA resource for associated STAs, and AID=2045 means UORA resource for un-associated STAs. Accordingly, the first to third RU resources in FIG. 9 are used as UORA resources for associated STAs, the fourth to fifth RU resources in FIG. 9 are used as UORA resources for un-associated STAs, and the sixth RU resource in FIG. 9 is used as a resource for a normal UL MU.

[0094] In the example of Fig. 9, the OBO (OFDMA random access Back Off) counter of STA1 is decremented to 0, and STA1 randomly selects the second RU resource (AID 0, RU 2). Also, since the OBO counter of STA2 / 3 is greater than 0, no uplink resource is assigned to STA2 / 3. Also, in Fig. 9, STA4 includes its own AID (i.e., AID=3) in the trigger frame, so it is assigned the resource of RU 6 without backoff.

[0095] Specifically, since STA1 in Fig. 9 is an associated STA, there are a total of three eligible RA RUs for STA1 (RU 1, RU 2, RU 3), and accordingly STA1 decrements its OBO counter by 3, so that the OBO counter is now 0. Also, since STA2 in Fig. 9 is an associated STA, there are a total of three eligible RA RUs for STA2 (RU 1, RU 2, RU 3), and accordingly STA2 decrements its OBO counter by 3, but the OBO counter is now greater than 0. Also, since STA3 in Fig. 9 is an un-associated STA, there are a total of two eligible RA RUs for STA3 (RU 4, RU 5), and accordingly STA3 decrements its OBO counter by 2, but the OBO counter is now greater than 0.

[0096] The PPDU transmitted / received in the STA in this specification is described as follows.

[0097] FIG. 10 shows an example of a PPDU used in this specification.

[0098] 10 may be referred to by various names such as EHT PPDU, transmit PPDU, receive PPDU, first type or Nth type PPDU, etc. For example, in this specification, PPDU or EHT PPDU may be referred to by various names such as transmit PPDU, receive PPDU, first type or Nth type PPDU, etc. Also, EHT PPU is used in EHT systems and / or new wireless LAN systems that improve on EHT systems.

[0099] The PPDU in FIG. 10 may indicate some or all of the PPDU types used in the EHT system. For example, the example in FIG. 10 is used for both the single-user (SU) mode and the multi-user (MU) mode. In other words, the PPDU in FIG. 10 may be a PPDU for one receiving STA or multiple receiving STAs. When the PPDU in FIG. 10 is used for the Trigger-based (TB) mode, the EHT-SIG in FIG. 10 may be omitted. In other words, a STA that receives a Trigger frame for Uplink-MU (UL-MU) communication may transmit a PPDU in the example in FIG. 10 with the EHT-SIG omitted.

[0100] In FIG. 10, the L-STF to the EHT-LTF can be called a preamble or a physical preamble, and are generated / transmitted / received / acquired / decoded in the physical layer.

[0101] The subcarrier spacing of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-SIG fields in Fig. 10 is set to 312.5 kHz, and the subcarrier spacing of the EHT-STF, EHT-LTF, and Data fields is set to 78.125 kHz. That is, the tone index (or subcarrier index) of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-SIG fields can be expressed in units of 312.5 kHz, and the tone index (or subcarrier index) of the EHT-STF, EHT-LTF, and Data fields can be expressed in units of 78.125 kHz.

[0102] In the PPDU of FIG. 10, the L-LTF and L-STF may be the same as conventional fields.

[0103] The L-SIG field in FIG. 10 may include, for example, 24-bit 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 regarding the length or time duration of the PPDU. For example, the value of the 12-bit Length field is determined based on the type of PPDU. For example, if the PPDU is a non-HT, HT, VHT PPDU, or an EHT PPDU, the value of the Length field is determined as a multiple of 3. For example, if the PPDU is an HE PPDU, the value of the Length field is determined as a "multiple of 3+1" or a "multiple of 3+2". In other words, for a non-HT, HT, VHT PPDU, or an EHT PPDU, the value of the Length field may be determined as a multiple of 3, and for a HE PPDU, the value of the Length field is determined as a "multiple of 3+1" or a "multiple of 3+2".

[0104] For example, the transmitting STA may apply coding that is BCC based on a code rate of 1 / 2 to the 24-bit information of the L-SIG field. Then, the transmitting STA may obtain 48 BCC coded bits. BPSK modulation is applied to the 48 coded bits to generate 48 BPSK symbols. The transmitting STA may map the 48 BPSK symbols to positions other than the pilot subcarrier {subcarrier index -21, -7, +7, +21} and the DC subcarrier {subcarrier index 0}. As a result, the 48 BPSK symbols are 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 further map signals of {-1, -1, -1, 1} to subcarrier indexes {-28, -27, +27, 28}. The above signal is used for channel estimation for the frequency domain corresponding to {-28, -27, +27, 28}.

[0105] The transmitting STA can generate a RL-SIG, which is generated the same as the L-SIG. BPSK modulation is applied to the RL-SIG. The receiving STA can determine that the received PPDU is an HE PPDU or an EHT PPDU based on the presence of the RL-SIG.

[0106] A Universal SIG (U-SIG) is inserted after the RL-SIG in Figure 10. The U-SIG can be called by various names such as the first SIG field, first SIG, first type SIG, control signal, control signal field, and first (type) control signal.

[0107] The U-SIG can include N-bit information and can include information for identifying the type of EHT PPDU. For example, the U-SIG is configured based on two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG can have a duration of 4 us. Each symbol of the U-SIG is used to transmit 26-bit information. For example, each symbol of the U-SIG is transmitted and received based on 52 data tones and 4 pilot tones.

[0108] For example, A-bit information (e.g., 52 un-coded bits) is transmitted through the U-SIG (or U-SIG field), the first symbol of the U-SIG transmits the first X-bit information (e.g., 26 un-coded bits) of the total A-bit information, and the second symbol of the U-SIG transmits the remaining Y-bit information (e.g., 26 un-coded bits) of the total A-bit information. For example, the transmitting STA can obtain 26 un-coded bits included in each U-SIG symbol. The transmitting STA can perform convolutional encoding (i.e., BCC coding) based on a rate of R=1 / 2 to generate 52-coded bits and perform interleaving on the 52-coded bits. The transmitting STA can perform BPSK modulation on the interleaved 52-coded bits to generate 52 BPSK symbols assigned to each U-SIG symbol. One U-SIG symbol is transmitted based on 56 tones (subcarriers) from subcarrier index -28 to subcarrier index +28, excluding DC index 0. The 52 BPSK symbols generated by the transmitting STA are transmitted based on the remaining tones (subcarriers) excluding the pilot tones -21, -7, +7, and +21.

[0109] For example, A-bit information (e.g., 52 un-coded bits) transmitted by a U-SIG may include a CRC field (e.g., a 4-bit long field) and a tail field (e.g., a 6-bit long field). The CRC field and the tail field are transmitted via the second symbol of the U-SIG. The CRC field is generated based on 26 bits assigned to the first symbol of the U-SIG and the remaining 16 bits in the second symbol excluding the CRC / tail field, and is generated based on a conventional CRC calculation algorithm. In addition, the tail field is used to terminate the trellis of the convolutional decoder, and is set to, for example, "000000".

[0110] The A-bit information (e.g., 52 uncoded bits) transmitted by a U-SIG (or U-SIG field) can be divided into version-independent bits and version-dependent bits. For example, the size of the version-independent bits can be fixed or variable. For example, the version-independent bits are assigned only to the first symbol of the U-SIG, or the version-independent bits are assigned to both the first and second symbols of the U-SIG. For example, the version-independent bits and version-dependent bits can be referred to by various names, such as the first control bits and the second control bits.

[0111] For example, the version-independent bits of the U-SIG may include a 3-bit PHY version identifier. For example, the 3-bit PHY version identifier may include information related to the PHY version of the transmitted / received PPDU. For example, a first value of the 3-bit PHY version identifier may indicate that the transmitted / received PPDU is an EHT PPDU. In other words, when a transmitting STA transmits an EHT PPDU, the transmitting STA may set the 3-bit PHY version identifier as a first value. In other words, a receiving STA may determine that the received PPDU is an EHT PPDU based on the PHY version identifier having the first value.

[0112] For example, the version-independent bits of the U-SIG may include a one-bit UL / DL flag field, where a first value of the one-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.

[0113] For example, the version-independent bits of the U-SIG can include information about the length of the TXOP and information about the BSS color ID.

[0114] For example, if the EHT PPDU is divided into different types (e.g., EHT PPDUs associated with SU mode, EHT PPDUs associated with MU mode, EHT PPDUs associated with TB mode, EHT PPDUs associated with Extended Range transmission, etc.), the information about the type of EHT PPDU is included in the version-dependent bits of the U-SIG.

[0115] For example, the U-SIG may include information regarding 1) a bandwidth field including information regarding the bandwidth, 2) a field including information regarding the MCS technique applied to the EHT-SIG, 3) an indication field including information related to whether dual subcarrier modulation (DCM) technique is applied to the EHT-SIG, 4) a field including information regarding the number of symbols used for the EHT-SIG, 5) a field including information regarding whether the EHT-SIG is generated across the entire band, 6) a field including information regarding the type of EHT-LTF / STF, and 7) a field indicating the length of the EHT-LTF and the CP length.

[0116] In the following example, signals indicated as (transmit / receive / up / down) signals, (transmit / receive / up / down) frames, (transmit / receive / up / down) packets, (transmit / receive / up / down) data units, (transmit / receive / up / down) data, etc. may be signals transmitted and received based on the PPDU of FIG. 10. The PPDU of FIG. 10 is used to transmit and receive various types of frames. For example, the PPDU of FIG. 10 is used for a control frame. Examples of the control frame may include RTS (request to send), CTS (clear to send), PS-Poll (Power Save-Poll), Block ACK Req, Block Ack, NDP (Null Data Packet) announcement, and Trigger frame. For example, the PPDU of FIG. 18 is used for a management frame. Examples of the management frame may include a Beacon frame, a (Re-)Association Request frame, a (Re-)Association Response frame, a Probe Request frame, and a Probe Response frame. For example, the PPDU in Fig. 10 is used for a data frame, and for example, the PPDU in Fig. 10 is also used for simultaneously transmitting at least two or more of a control frame, a management frame, and a data frame.

[0117] FIG. 11 shows a variation of the transmitting device and / or the receiving device of this specification.

[0118] Each device / STA in (a) / (b) of Figure 1 can be modified as shown in Figure 11. The transceiver 630 in Figure 11 can be the same as the transceivers 113 and 123 in Figure 1. The transceiver 630 in Figure 11 can include a receiver and a transmitter.

[0119] The processor 610 in Figure 11 may be the same as the processors 111, 121 in Figure 1. Or, the processor 610 in Figure 11 may be the same as the processing chips 114, 124 in Figure 1.

[0120] The memory 150 in Figure 11 may be the same as the memories 112, 122 in Figure 1. Alternatively, the memory 150 in Figure 11 may be a separate external memory that is different from the memories 112, 122 in Figure 1.

[0121] 11, a power management module 611 manages power to the processor 610 and / or transceiver 630. A battery 612 provides power to the power management module 611. A display 613 outputs results processed by the processor 610. A keypad 614 receives inputs used by the processor 610. The keypad 614 may be represented on the display 613. A SIM card 615 may be an integrated circuit used to securely store an international mobile subscriber identity (IMSI) and associated keys used to identify and authenticate a subscriber in mobile phone devices such as mobile phones and computers.

[0122] 11, the speaker 640 can output sound-related results processed by the processor 610. The microphone 641 can receive sound-related inputs used by the processor 610.

[0123] The technical features of the Multi-link (ML) supported by the STA in this specification are described below.

[0124] The STA (AP and / or non-AP STA) in this specification can support MultiLink (ML) communication. ML communication means communication that supports multiple links. Links related to ML communication can include channels in the 2.4 GHz band, 5 GHz band, and 6 GHz band (e.g., 20 / 40 / 80 / 160 / 240 / 320 MHz channels).

[0125] The multiple links used for ML communication are set in various ways. For example, the multiple links supported by one STA for ML communication may be multiple channels in the 2.4 GHz band, multiple channels in the 5 GHz band, or multiple channels in the 6 GHz band. Or, the multiple links supported by one STA for ML communication 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). On the other hand, at least one of the multiple links supported by one STA for ML communication may be a channel to which preamble puncturing is applied.

[0126] STA can perform ML setup to perform ML communication. ML setup can be performed based on management frames and control frames such as Beacon, Probe Request / Response, and Association Request / Response. For example, information about ML setup is included in element fields included in Beacon, Probe Request / Response, and Association Request / Response.

[0127] When the ML setup is completed, an enabled link for ML communication is determined. The STA can perform frame exchange through at least one of the multiple links determined as the enabled link. For example, the enabled link is used for at least one of the management frame, control frame, and data frame.

[0128] When one STA supports multiple links, the transceiver supporting each link can operate as one logical STA. For example, one STA supporting two links can be represented as one ML device (Multi Link Device; MLD) including a first STA for the first link and a second STA for the second link. For example, one AP supporting two links can be represented as one AP MLD including a first AP for the first link and a second AP for the second link. Also, one non-AP supporting two links can be represented as one non-AP MLD including a first STA for the first link and a second STA for the second link.

[0129] As follows, more specific aspects regarding the ML setup are described.

[0130] MLD (AP MLD and / or non-AP MLD) can transmit information about links that the MLD can support through ML setup. The information about the links can be configured in various ways. For example, the information about the links can 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 uplink / downlink links supported by the MLD (or STA), 3) information about the location / band / resource of uplink / downlink links supported by the MLD (or STA), 4) information about frame types (management, control, data, etc.) available or preferred in at least one uplink / downlink link, 5) ACK policy information available or preferred in at least one uplink / downlink link, and 6) information about traffic identifiers (TIDs) available or preferred in at least one uplink / downlink link. TIDs are related to the priority of traffic data and are expressed by eight types of values ​​according to conventional WLAN standards. That is, eight TID values ​​are defined corresponding to four access categories (AC) (AC_BK (background), AC_BE (best effort), AC_VI (video), and AC_VO (voice)) according to the conventional wireless LAN standard.

[0131] For example, all TIDs are pre-configured by mapping to uplink / downlink links. Specifically, if no negotiation is performed through ML setup, all TIDs are used for ML communication, and if mapping between uplink / downlink links and TIDs is negotiated through additional ML setup, the negotiated TID is used for ML communication.

[0132] Through ML setup, multiple links that can be used by the sending MLD and receiving MLD related to ML communication are set, which can be called "enabled links." An "enabled link" can be called by various expressions, such as the first link, the second link, the sending link, and the receiving link.

[0133] After the ML setup is completed, the MLD can update the ML setup. For example, if an update is required for the link information, the MLD can send information about a new link. The information about the new link is sent based on at least one of a management frame, a control frame, and a data frame.

[0134] The device described below may be the device in Fig. 1 and / or Fig. 11, and the PPDU may be the PPDU in Fig. 10. The device may be an AP or a non-AP STA. The device described below may be an AP MLD (multi-link device) that supports multi-link or a non-AP STA MLD.

[0135] Since 802.11ax, the standard EHT (Extremely High Throughput) under discussion takes into account a multi-link environment that uses one or more bands simultaneously. If a device supports multi-link, it can use one or more bands (e.g., 2.4 GHz, 5 GHz, 6 GHz, 60 GHz, etc.) simultaneously or alternately.

[0136] In the following specification, MLD means multi-link device. MLD has one or more connected STAs and one MAC SAP (service access point) that leads to the upper link layer (Logical Link Control, LLC). MLD means physical device or logical device. In the following, device means MLD.

[0137] In the following specification, the transmitting device and the receiving device refer to MLD. The first link of the receiving / transmitting device may be a terminal (e.g., STA or AP) included in the receiving / transmitting device that performs signal transmission / reception through the first link. The second link of the receiving / transmitting device may be a terminal (e.g., STA or AP) included in the receiving / transmitting device that performs signal transmission / reception through the second link.

[0138] In IEEE 802.11be, two types of multi-link operation can be supported. For example, STR (simultaneous transmit and receive) and non-STR operation are considered. For example, STR can be called asynchronous multi-link operation, and non-STR can be called synchronous multi-link operation. Multi-link can include multiple bands. That is, multi-link can mean links included in multiple frequency bands, and can also mean multiple links included in one frequency band.

[0139] EHT (11be) takes into account multi-link technology, where multi-link can include multi-band. In other words, multi-link can refer to links of multiple bands, and can simultaneously refer to multiple multi-links within one band. Broadly speaking, two types of multi-link operation are considered: Asynchronous operation, which allows simultaneous TX / RX on multiple links, and Synchronous operation, which does not. In the following, the capability to simultaneously receive and transmit on multiple links is called STR (simultaneous transmit and receive), and STAs with STR capability are called STR MLD (multi-link Device), and STAs without STR capability are called non-STR MLD.

[0140] In the following description, for convenience of explanation, the MLD (or a processor of the MLD) is described as controlling at least one STA, but this is not limited thereto. As described above, the at least one STA can also transmit and receive signals independently of the MLD.

[0141] According to one embodiment, the AP MLD or non-AP MLD is configured with a structure having multiple links. In other words, the non-AP MLD can support multiple links. The non-AP MLD can include multiple STAs. Each of the multiple STAs can have its own link.

[0142] The EHT standard (802.11be standard) considers the MLD (Multi-Link Device) structure, in which one AP / non-AP MLD supports multiple links, as its main technology. STAs included in a non-AP MLD can transmit information to other STAs in the non-AP MLD via one link. This reduces the overhead of frame exchange. It also increases the link usage efficiency of STAs and reduces power consumption.

[0143] FIG. 12 shows an example of the structure of a non-AP MLD.

[0144] Referring to FIG. 12, the non-AP MLD is configured with a structure having multiple links. In other words, the non-AP MLD can support multiple links. The non-AP MLD can include multiple STAs. Each of the multiple STAs can have its own link. Although FIG. 12 shows an example of the non-AP MLD structure, the AP MLD structure is also configured in the same manner as the example of the non-AP MLD structure shown in FIG. 12.

[0145] For example, a non-AP MLD may include STA1, STA2, and STA3. STA1 may operate on Link 1, which is included in the 5 GHz band. STA2 may operate on Link 2, which is included in the 6 GHz band. STA3 may operate on Link 3, which is included in the 6 GHz band. The bands that Link 1 / 2 / 3 are included in are exemplary and are included in 2.4, 5, and 6 GHz.

[0146] In this way, in the case of AP / non-AP MLD supporting multi-link, each AP of AP MLD and each STA of non-AP MLD are connected to each link through the link setup process. Then, the connected link is changed or reconnected to another link by AP MLD or non-AP MLD depending on the situation.

[0147] In addition, in the EHT standard, a link can be divided into an anchored link and a non-anchored link to reduce power consumption. Anchored links and non-anchored links can be called variously. For example, an anchored link can be called a primary link, and a non-anchored link can be called a secondary link.

[0148] According to one embodiment, an AP MLD that supports multi-link can be managed by designating each link as an anchored link or a non-anchored link. An AP MLD can support one or more of multiple links as an anchored link. A non-AP MLD can be used by selecting one or more of its own anchored links from the anchored link list (a list of anchored links supported by the AP MLD).

[0149] For example, the anchored link is used not only for frame exchange for synchronization but also for non-data frame exchange (i.e., Beacon and Management frames), and the non-anchored link is used only for data frame exchange.

[0150] Non-AP MLD can only monitor the anchored link to receive beacons and management frames during the idle period. Therefore, in the case of non-AP MLD, it is necessary to connect to at least one anchored link to receive beacons and management frames. The one or more anchored links must always be kept in an enabled state. In contrast, non-anchored links are used only for data frame exchange. Therefore, STAs corresponding to non-anchored links (or STAs connected to non-anchored links) can enter doze during the idle period when the channel / link is not being used. This has the effect of reducing power consumption.

[0151] Therefore, in the following specification, a protocol is proposed in which AP MLD or non-AP MLD dynamically recommends or requests link reconnection depending on the situation for efficient link connection. In addition, in the following specification, an anchored link reconnection protocol is further proposed that takes into account the characteristics of not only normal links but also anchored links used for the purpose of power reduction.

[0152] Example of Link Change and Reconnection

[0153] According to one embodiment, each link between the AP MLD and the non-AP MLD is determined in an association or (re)association process. At this time, the AP MLD and the non-AP MLD can perform frame exchange via the connected link. A specific embodiment in which the AP MLD and the non-AP MLD are connected via the link setup process will be described with reference to FIG. 13.

[0154] FIG. 13 shows an example in which an AP MLD and a non-AP MLD are connected via a Link setup process.

[0155] 13, the AP MLD can include AP1, AP2, and AP3. The non-AP MLD can include STA1 and STA2. AP1 and STA1 are connected via Link 1. AP2 and STA2 are connected via Link 2.

[0156] For example, AP1 and STA1 are connected via Link 1 through a first link setup process. AP2 and STA2 are connected via Link 2 through a second link setup process. In another example, AP MLD and non-AP MLD are connected via one link setup process. In other words, AP MLD and non-AP MLD are connected via Link 1 and Link 2 based on one link setup process.

[0157] As described above, each AP and STA can exchange frames through the connected links, and information of other APs or other STAs on other links is transmitted and received through one link.

[0158] However, after this link setup process, the AP MLD or non-AP MLD may request a link change or reconnection for more efficient frame exchange (eg, load balancing or interference avoidance) depending on the situation / environment.

[0159] An embodiment relating to link change or reconnection will be described with reference to FIG.

[0160] FIG. 14 shows an example where a Link is changed or reconnected.

[0161] Referring to FIG. 14, STA2 is conventionally connected to AP2. Then, the data load of AP2 may be excessive. STA2 is reconnected to AP3, which has a relatively small data load. In this case, AP MLD and non-AP MLD can perform efficient data exchange.

[0162] FIG. 15 shows a specific example in which a link is changed or reconnected.

[0163] 15, AP1 of AP MLD is connected to STA1 of non-AP MLD via link 1. AP2 of AP MLD is connected to STA2 of non-AP MLD via link 2. Thereafter, STA2 can attempt / request connection to AP3 via link change or reconnection, and STA2 is connected to AP3 via link 2 based on the link change or reconnection.

[0164] According to an embodiment, the non-AP MLD and the AP MLD can request a link transition to improve performance. The AP MLD and the non-AP MLD can transmit / receive / exchange various information per current link and information on the link state. Therefore, the AP MLD and the non-AP MLD can select a more suitable link for transmitting / receiving a signal based on the various information per current link and the link state, and can transmit the above information to support the selection. For example, the various information per current link can include information on the data traffic load per link and the channel access capability between links. For example, the link state is set as disable or enable.

[0165] In the following specification, the process in which the AP MLD / non-AP MLD negotiates with the non-AP MLD / AP MLD to request a change or reconnection to another link other than the connected link in order to improve performance is called "Link switching negotiation." The name "Link switching negotiation" may be called in various ways and may be subject to change.

[0166] In the link switching negotiation process, the non-AP MLD (or AP MLD) requests that the link connected to a specific STA be changed to another link, and the AP MLD (or non-AP MLD) can respond to this request via a request acknowledge or reject message.

[0167] As an example, as shown in FIG. 15, if a link change is agreed upon through link switching negotiation, the STA can perform a link re-setup process in which the existing link is changed from AP2 to AP3 and reconnected.

[0168] In the following, the link change or reconnection process will be described separately for the case where AP MLD is requested and the case where non-AP MLD is requested.

[0169] An embodiment in which AP MLD requests a link change or reconnection

[0170] According to one embodiment, the AP MLD can request a link change or reconnection to the non-AP MLD for efficient data transmission. For example, for load balancing, the AP MLD can request a STA to change or reconnect a more efficient link based on the data traffic of each AP.

[0171] For example, the AP MLD can calculate / check / determine a link suitable for a non-AP MLD STA based on data traffic load information for each AP and / or channel access capability information between each link (e.g., information on STR (Simultaneous TX / RX) capability, etc.) Thereafter, the AP MLD can request a link change or reconnection to the STA (or non-AP MLD) based on data traffic load information for each AP and / or channel access capability information between each link, etc.

[0172] As described above, when a link change request is made, the AP MLD can transmit the link information that it considers to be the most suitable to the non-AP MLD via a request message. For example, the request message can include a beacon or a management frame.

[0173] In relation to the above-described embodiment, an element or field including the most suitable link information is newly proposed. The newly proposed element or field is defined as a "recommended link." The "recommended link" is merely an example, and the name of the specific element or field may be changed.

[0174] recommend link(element / field) : An element or field for the AP MLD to recommend the most suitable link to a non-AP MLD STA based on various information for each link (e.g., data load for each link, etc.). For example, the recommend link (element / field) is indicated by AP MLD Link ID information or AP BSS information, etc. In other words, the recommend link (element / field) can include AP MLD Link ID information or AP BSS information, etc.

[0175] According to one embodiment, the recommend link (element / field) is optionally included in the Link switching Response and transmitted. For example, the STA can establish a connection to the link recommended by the AP based on the element / field (i.e., the recommend link). In another example, the STA can execute a connection request to a link other than the indicated link based on the element / field (i.e., the recommend link) and additional information that the STA has.

[0176] A specific signal exchange process of AP MLD and non-AP MLD according to the above embodiment is described via FIG.

[0177] FIG. 16 shows the operation of AP MLD and non-AP MLD for link change or reconnection.

[0178] 16, when STA2 is connected to AP2 via link2, a lot of data traffic may be concentrated on AP2. In other words, when STA2 is connected to AP2 via link2, a lot of data traffic occurs on AP2.

[0179] The AP MLD (or AP2) can request the non-AP MLD (or STA2) to reconnect to AP3, which has relatively few STA connections. Normally, a message to request reconnection is sent to the STA that desires to reconnect (i.e., STA2), but depending on the situation (e.g., channel situation or link state), it may be sent to any STA (i.e., other STA). In other words, the STA to which a request message (e.g., Link switching request frame) to request reconnection is sent can be changed based on the channel situation or link state.

[0180] For example, if the STA (i.e., STA2) that has received the request message for requesting reconnection approves the request, it can transmit a response message (e.g., a Link switching Response frame) of "Accept." In another example, if the STA (i.e., STA2) rejects the request, it can transmit a response message of "Decline."

[0181] Normally, the STA that approves the reconnection (i.e., STA2) sends a response message to the existing link (the link connected before the reconnection), but the response message can be sent via any link (i.e., another STA) using the multi-link characteristic.

[0182] If STA2 accepts the link reconnection request, after sending a response message, STA2 can disconnect from the existing AP2 and request a link reconnection to AP3. At this time, the reconnection request process can be performed in the same way as the existing link setup process between MLDs. After the link setup process between AP3 and STA2 is completed, STA2 can perform frame exchange with AP3 through Link2.

[0183] Conversely, if STA2 rejects the link reconnection request, STA2 and AP2 can continue to use the existing connected link (i.e., link2).

[0184] According to one embodiment, when an AP requests a STA to change a link, if the AP recommends a suitable link, the STA may or may not change the link to the recommended link. For example, the above-mentioned recommend link is used for the AP to recommend a suitable link to the STA.

[0185] For example, the STA may approve a link change in a response message to a request message for requesting reconnection to the AP. The STA may approve / confirm a link change to a recommended link, and may also request another link change from the AP based on information other than the information included in the request message.

[0186] Therefore, the AP needs to inform the STA of the approval or disapproval of the response message. To this end, the AP can transmit to the STA a Confirmation message (e.g., a link switching confirmation frame) in response to the response message (e.g., a Link Switching Response frame) of the STA.

[0187] The specific operations of AP MLD and non-AP MLD in the above-mentioned embodiment will be described with reference to FIG.

[0188] FIG. 17 shows the operation of AP MLD and non-AP MLD for link change or reconnection.

[0189] 17, the AP2 can include the recommended link information to request a link change to the STA2. In other words, the AP2 can send a link switching request frame including the recommended link information to the STA2.

[0190] STA2 can transmit whether or not the link request is approved via a Link switching Response frame.

[0191] For example, when link switching is approved, STA2 can transmit a link switching response frame including link information to be changed. At this time, the link information to be changed may or may not be the same as the recommended link.

[0192] In another example, if STA2 selects a link other than the recommended link provided by AP2 and responds with a Link switching Response frame, the AP may send a message to the STA regarding the final approval or disapproval of the link, which may be called a Link switching confirmation frame.

[0193] For example, AP2 can approve the link change to the link determined by STA2 via the link switching confirmation frame. STA2 can attempt to change the link to the link specified by itself based on the link switching confirmation frame.

[0194] As another example, AP2 can refuse to change the link to the link determined by STA2 via the link switching confirmation frame. STA2 and AP2 can maintain the connection with the already connected link without changing the link.

[0195] The embodiment shown in Fig. 17 is also applicable to the case where the AP transmits a Link switching request frame without including recommended link information. For example, when an AP (e.g., AP2) transmits a Link switching request frame to a STA (e.g., STA2) without recommended link information, the STA can directly specify a changed Link based on its own information and then respond to the AP via a Link switching Response frame. Even in this case, the AP must ultimately transmit a Link switching confirmation frame for approval. Therefore, the embodiment in which the AP transmits a Link switching confirmation frame is also applicable even when the Link switching request frame does not include recommended link information.

[0196] Embodiment in which non-AP MLD requests link change or reconnection

[0197] According to one embodiment, the non-AP MLD can request a link change or reconnection to the AP MLD for efficient data transmission. For example, in order to use the STR capability during data transmission, the non-AP MLD can request a link change or reconnection to the AP MLD.

[0198] FIG. 18 shows the operation of AP MLD and non-AP MLD for link change or reconnection.

[0199] Referring to Fig. 18, AP MLD and non-AP MLD can perform link switching negotiation. STA2 of non-AP MLD can transmit a link switching request frame to AP2 of AP MLD. AP2 of AP MLD can transmit a link switching response frame to STA2 of non-AP MLD in response to the link switching request frame. The link switching request frame or the link switching response frame is transmitted and received via the link to be changed, but is not limited to this. The link switching request frame or the link switching response frame is transmitted and received via various links, not just the link to be changed.

[0200] Non-AP MLD can request link change or reconnection through various methods. Three methods are proposed below for non-AP MLD to request link change or reconnection. Specifically, the three methods are Solicited method, Unsolicited method, and General method are described in order.

[0201] 1) Solicited method: A method in which a non-AP MLD requests various information for link (re)selection from an AP MLD and receives various information through this. For example, the various information may include information on capability, operation element, and BSS Parameters.

[0202] According to one embodiment, the method in which a STA requests information on other APs in the connected AP MLD is used not only when re-setting a link but also in various other cases. For example, after multi-link setup, a STA can request BSS parameter information of other APs for link switching and select the best link based on the received information. Or, in a discovery process, a STA can request BSS load information of each AP from the AP MLD and select a link for executing link setup based on the received information. (However, it is assumed that the number of APs in the AP MLD is greater than the number of STAs in non-AP MLD.)

[0203] Therefore, the AP that receives the information request message can send any information, such as capability information, BSS parameter information, critical parameters, and / or operation element information, to all APs in the AP MLD. The above examples are all applicable to the embodiments described below.

[0204] 2) Unsolicited Method: A method in which an AP transmits various information for link (re)selection without a separate information request from a non-AP MLD. A STA can utilize the received information in various situations. According to one embodiment, a method in which an AP in an AP MLD transmits information on other APs without a separate information request from a STA is used not only in the case of reconfiguring a link but also in various other cases. Therefore, an AP that receives an information request message can transmit any information, such as capability information, BSS parameter information, critical parameters, and / or operation element information, for all APs in the AP MLD. The above examples are all applicable to the embodiments described below.

[0205] 3) General Method: A method in which a non-AP MLD requests link (re)selection without additional information based on information previously acquired through a beacon frame, etc.

[0206] 1)Solicited method

[0207] In the following, an embodiment relating to the above-mentioned solicited method will first be described.

[0208] According to one embodiment, the non-AP MLD may request information for selecting a link suitable for the AP MLD before changing or reconnecting the link. The STA may use data load information for each AP or capability information for each link (or information for other links) to select a suitable link.

[0209] For example, the Capability information for each link is included in a Beacon frame and is periodically transmitted.

[0210] In another example, the link-specific capability information may not be included in the beacon frame transmitted periodically as optional information. Or, to reduce frame overhead, only information on the link to which the STA is connected or some related links is received. Or, if the beacon reception period is long due to the characteristics of the non-AP MLD (e.g., a low-power device), the non-AP MLD may not be able to receive link-specific capability information for more appropriate link selection.

[0211] In the above case, the non-AP MLD can request the latest information of link-specific capability information and each link-specific information of the AP MLD (e.g., BSS parameter information or operation element information, etc.). The link-specific capability information and the link-specific information can include not only the link being transmitted or received but also other links. For example, a field of a QoS data frame (A-Control field of the 11ax standard), a management frame, a probe response / request frame, a PS-Poll frame, or a null frame can be used to request / send the latest information. Alternatively, a separate new frame is defined to request / send the latest information.

[0212] According to one embodiment, in order to request the latest information of the link-specific capability information and the AP MLD information for each link, the STA may transmit a request message to the AP to request information required for link reselection. For example, the previously defined Probe Request frame for the request message is reused. In another example, a new frame for the request message is defined.

[0213] According to an embodiment, the STA may specify specific information required through the request message and request it from the AP. The specific information that can be specified may be changed depending on the situation. That is, the STA may request only information corresponding to a specific link or only information corresponding to a specific capability. For example, the information corresponding to a specific link may include information regarding the BSS load / parameters of the specific link. Also, the information corresponding to a capability may include BSS load information of all links or BSS load information of a specific link. In this case, the AP may transmit only the information specified by the STA through a response message. Specific embodiments regarding specific information request and response will be described through embodiments regarding IOM definition and operation.

[0214] As another example, the STA may request all capability information (including other link information) currently held by the AP MLD via the request message.

[0215] As in the above example, an embodiment for transmitting all information possessed by the AP or an embodiment for transmitting only specific information designated by the STA may be defined / configured in various ways. For example, the AP may transmit all information or designated information based on a separate field or bitmap to indicate (or transmit) only specific information.

[0216] Normally, a message requesting information from the AP MLD is sent via the STA that wishes to reconnect, but depending on the situation (channel conditions or link state), it may be sent to any STA (ie, other STA).

[0217] The AP MLD that receives the request message can transmit a response message (i.e., information message) including information requested by the STA (e.g., link-specific data load information, link-to-link STR capability information, etc.) to the non-AP MLD. For example, if a conventional Probe Request frame is reused for the request message, the AP (or AP MLD) needs to respond using a Probe Response frame in the response message.

[0218] The response message is also normally sent via the AP that received the Request message, but can also be sent to any AP (ie, other APs) using the multi-link characteristic.

[0219] Alternatively, the AP MLD can send a "recommend link" element recommending a suitable link for the STA together with a response message including the above-mentioned information (e.g., the latest information required for link reselection).

[0220] The above-mentioned solicited method is used for link change or reconnection in non-AP MLD STA. For example, if a non-AP MLD STA wants to reselect a link due to link congestion, the non-AP MLD STA can request BSS load information and BSS parameter information for each link of the connected AP MLD through the solicited method. The AP that receives this request message can send the link and information specified by the STA in a response message.

[0221] In the following, the above-mentioned request message and response message will be described as an information request message and an information response message to distinguish them from a request message for a link change and a response message for a link change.

[0222] Based on the information included in the above-mentioned information response message, the STA can reselect a suitable link and request a link change or reconnection to the AP MLD via a request message for link change. The request message for link change can include AP information and link information to which the STA will reconnect.

[0223] When the AP MLD receives the request message, it can send a response message of "Accept" if it accepts the request, or it can send a response message of "Decline" if it rejects the request.

[0224] If the request is accepted, the AP can perform link(re)setup based on frame exchange via the link of the reselected AP after sending the response message. Conversely, if the request is rejected, the STA can continue to use the existing connected link.

[0225] A specific example of AP MLD and non-AP MLD operations related to the Solicited method will be described with reference to FIG.

[0226] FIG. 19 shows the operation of AP MLD and non-AP MLD for link change or reconnection.

[0227] 19, when STA2 of non-AP MLD wants to reselect a connected link, STA2 can transmit an Info request message to AP MLD via Link2. The AP MLD receiving this can transmit an Info response message including information required for link reselection of non-AP MLD. Based on the information included in the above-mentioned Info response message, STA2 of non-AP MLD can transmit a request message for link change (i.e., Link switching request frame) to AP2 of AP MLD. Thereafter, STA2 can receive a response message for link change (i.e., Link switching request frame) and perform link(re)set-up for link change.

[0228] The embodiments of the information request proposed in this specification are also used / applied when the STA requests necessary information from the AP. If the information included in the frame (e.g., beacon) that the STA receives from the AP is insufficient, the STA can request the AP for the missing information. For example, if the AP does not include information on the other link and only transmits information on the connected link or transmits only information on whether the information on the other link is updated, the STA can request the AP for the missing information.

[0229] A specific example of the above embodiment will be described with reference to FIG.

[0230] FIG. 20 shows the operation of non-AP MLD to request information about other APs.

[0231] Referring to FIG. 20, AP MLD (or AP1 to AP3) can transmit only information regarding whether information on other APs (i.e., links) has been updated to STAs via a beacon frame. Therefore, STA2 can transmit an Info request message (or Info request frame) to AP2. STA2 can receive an Info response message (or Info message) based on the Info request message. STA2 can receive / acquire information regarding other APs based on the Info response message.

[0232] For example, the Beacon may not include other AP information (eg, BSS load information, etc.) of the AP MLD, or AP2 may transmit only information regarding whether the other AP information has been updated (eg, version / update version).

[0233] STA2 may need information on AP1 (or information about AP1). STA2 can request the necessary information via AP2. STA2 can obtain the information on AP1 via a response message to the request. STA2 can use this to reselect an appropriate link for link switching the information on AP1. For example, a frame for link switching can be set in various ways.

[0234] Furthermore, the above-mentioned solicited method can also be used by a STA to obtain information on APs held by the AP MLD before multi-link setup. In the multi-link setup process of non-AP MLD and AP MLD, if the number of APs held by the AP MLD is greater than the number of STAs held by the non-AP MLD, the non-AP MLD STA needs to determine which AP of the AP MLD to set up a link with. In this case, the non-AP MLD STA can request link-specific information (e.g., BSS load information of APs held by the AP MLD) to recognize the status of each link from the AP of the AP MLD before multi-link setup. As an example, the STA can use a Probe Request in the request message. As another example, a new frame for the request message is defined. The STA can transmit a request message including an indicator for requesting a specific element (e.g., Request element, Extended Request element, or PV 1 Probe Response Option element) and an indicator for indicating specific link information (e.g., Link ID).

[0235] For example, a STA in a non-AP MLD can send a request message including an instruction requesting current BSS load information for all APs in the AP MLD to which it connects. The AP that receives the request message can include necessary information (BSS load information of all APs in the AP MLD to which the AP is connected) in a response message based on the STA's instruction and send it to the STA. In this case, the STA that has checked the BSS load information for each AP can select a link to connect to in the order of the BSS (i.e., AP) with the least BSS load. The STA can indicate the link selected during multi-link setup. In other words, information about the link selected during multi-link setup can be sent to the AP.

[0236] In this way, the STA can use the above-mentioned solicited method to acquire AP MLD information for each AP in order to select a link to connect to before multi-link setup.

[0237] In the following, a new element / field is proposed that contains information for a non-AP MLD STA to select a suitable link.

[0238] For example, 'ratio per Link' (element / field) is proposed. 'STA ratio per Link' can include information on the ratio of the number of STAs linked per Link. A specific example of 'STA ratio per Link' will be described with reference to FIG. 21.

[0239] FIG. 21 shows a specific example of the STA ratio per Link.

[0240] Referring to FIG. 21, STA ratio per Link (element / field) may include information regarding the number or ratio of STAs connected to each link in the entire AP MLD.

[0241] For example, if a total of 50 STAs are connected to an AP MLD with 3 links, 10 STAs are connected to Link 1 and 20 STAs are connected to Link 2. The AP MLD can transmit information on the STAs linked for each link via the STA ratio per Link (element / field) as a value or ratio (%) to the non-AP MLD.

[0242] For example, if information on the STAs linked to each Link is expressed as a value, Link 1 is expressed / set as 10 and Link 2 is expressed / set as 20. Therefore, the value of the STA ratio per Link 1 is set as 10. Also, the value of the STA ratio per Link 2 is set as 20.

[0243] As another example, if information about the STAs linked to each Link is expressed as a ratio, Link 1 is expressed / set as 20 (10 / 50)% and Link 2 is expressed / set as 40 (20 / 50)%. Therefore, the value of STA ratio per Link 1 is set as 20. Also, the value of STA ratio per Link 2 is set as 40.

[0244] The above examples are merely illustrative, and information on the STAs linked for each link may be set in various ways. In addition to the above examples, information on the STAs linked for each link may be set as a relative value.

[0245] Based on the information on the STAs linked to each link described above, the STA can confirm / acquire the number and ratio of STAs connected to each link and use this as information for link selection.

[0246] According to one embodiment, various information / elements / fields are included in the information response message in addition to the above-mentioned "ratio per Link" (element / field). For example, the following information / elements / fields are included in the information response message:

[0247] -BSS load information for each AP

[0248] -Link STR capability information

[0249] -TXOP information for each link

[0250] -NAV information for each link

[0251] -Recommended Link information (i.e., "recommend link" element)

[0252] -Link-specific connected STA ratio information (i.e., 'STA ratio per Link' element)

[0253] -Others

[0254] In addition to the above-mentioned information / element / field, various other information required for link selection is included in the information response message and transmitted.

[0255] A STA that receives information such as the above example can select an AP to change or reconnect to based on the received information, and then transmit a request message to request reconnection of the link. If the AP MLD that receives the request message accepts the request, it can transmit an "Accept" response message. If the AP MLD rejects the request, it can transmit a "Decline" response message.

[0256] If the request is accepted, the AP can perform frame exchange with the reselected AP via the link after sending the response message. If the request is rejected, the STA can continue to use the existing connected link.

[0257] 2)Unsolicited method

[0258] Unlike the Solicited method in which the non-AP MLD directly requests additional information, according to the Unsolicited method, the AP MLD can transmit additional information to the non-AP MLD via a Beacon frame or a separate frame (e.g., a field of a QoS data frame (A-Control field in the 11ax standard), a management frame, a FILS discovery frame, an unsolicited Probe Response frame, a PS-Poll frame, or a Null frame, etc.) without a request for additional information from the non-AP MLD. In another example, a new frame is defined as a frame for transmitting additional information to the non-AP MLD.

[0259] For example, if the beacon period is somewhat long, the non-AP MLD may lack the necessary information required for link switching or may not be the latest information. Therefore, the AP can transmit a frame including the link capability information of the AP MLD to the non-AP MLD. Thereafter, the non-AP STA can obtain the latest information on the capability of each link of the AP MLD. The frame is transmitted periodically or aperiodically.

[0260] As an example, if the frame is transmitted periodically, the AP may transmit a frame to share the latest information of the AP at a certain time interval. In this case, the time interval must be shorter than the period of the beacon transmitted by the AP. Also, if the FILS discovery frame is used in the frame, the frame is transmitted every 20us. As another example, a period agreed upon by the AP and the STA through capability negotiation may be used. For example, the transmission period may be indicated through the "periodic" field and "interval" field / subfield values ​​of the IOM capability element.

[0261] As another example, if the frame is transmitted aperiodically, the AP may transmit the frame whenever an update event occurs for AP information (capability, BSS parameter, operation element). As a specific example, whenever the link capability of the AP in the AP MLD is changed, the changed information is transmitted to the connected STA. In this case, the STA may maintain the latest information on the link capability.

[0262] According to the above example, since the non-AP STA does not transmit a separate request message for acquiring the link capability, the frame exchange overhead is relatively small compared to the solicited method. In addition, since the STA can receive updated information every time the main information is updated, the STA can effectively use the received information.

[0263] A specific example of the operation of AP MLD and non-AP MLD according to the Unsolicited method will be described with reference to FIG.

[0264] FIG. 22 shows the operation of AP MLD and non-AP MLD for link change or reconnection.

[0265] Referring to FIG. 22, the AP MLD can transmit essential information required for link reselection to the non-AP in a separate frame (e.g., a PS-Poll frame or a Null frame) without a separate request message from the non-AP MLD.

[0266] According to an embodiment, unlike Fig. 22, the AP MLD can transmit information on the link capability to the STA through a field of a DL frame (e.g., QoS data frame) that the AP MLD transmits to the non-AP MLD without a separate request message from the non-AP MLD. The operation of the AP MLD and the non-AP MLD according to the embodiment will be described with reference to Fig. 23.

[0267] FIG. 23 shows the operation of AP MLD and non-AP MLD for link change or reconnection.

[0268] Referring to FIG. 23, AP2 may transmit information about the other AP (or information about the other AP) to STA2 based on the DL frame (i.e., DL1). In other words, the DL frame may include information about the other AP. For example, information about the other AP may be included in the A-Control field of the 802.11ax standard. According to the embodiment, since an existing DL frame is utilized without a separate message, frame overhead can be reduced. If the Critical information of the other AP is changed and real-time information is required, updated information is transmitted via a separate message as in the embodiment of FIG. 23.

[0269] For example, the Critical information of an AP may include A to Q below.

[0270] A. Inclusion of a Channel Switch Announcement element

[0271] B. Inclusion of an Extended Channel Switch Announcement element

[0272] C. Modification of the EDCA parameters element

[0273] D. Inclusion of a Quiet element

[0274] E. Modification of the DSSS Parameter Set

[0275] F. Modification of the CF Parameter Set element

[0276] G. Modification of the HT Operation element

[0277] H. Inclusion of a WideBand width Channel Switch element

[0278] I. Inclusion of a Channel Switch Wrapper element

[0279] J. Inclusion of an Operating Mode Notification element

[0280] K. Inclusion of a Quiet Channel element

[0281] L. Modification of the VHT Operation element

[0282] M. Modification of the HE Operation element

[0283] N. Insertion of a Broadcast TWT element

[0284] O. Inclusion of the BSS Color Change Announcement element

[0285] P. Modification of the MU EDCA Parameter Set element

[0286] Q. Modification of the Spatial Reuse Parameter Set element

[0287] Therefore, the non-AP MLD can obtain the latest link capability information regardless of the beacon frame period. The non-AP MLD can select an appropriate link during link switching based on the received information. Based on the received information, the STA can reselect an appropriate link and request the AP MLD to change or reconnect the link. The request message can include AP information and link information to which the STA will reconnect. In addition, the AP MLD that receives this message can send an "Accept" response message if it accepts the request, or a "Decline" response message if it rejects the request.

[0288] If the request is accepted, the AP can perform link (re)setup via frame exchange on the link of the reselected AP after sending the response message. Conversely, if the request is rejected, the STA can continue to use the existing connected link.

[0289] 3)General method

[0290] According to the general method, a non-AP MLD can request a link change or reconnection based on its current information without requesting additional information. The information used at this time can include AP MLD information and non-AP MLD information (e.g., STR capability information for each link, link state (enable / disable) information, etc.) included in a previously received beacon or management frame.

[0291] Unlike the Solicited method, a STA can directly send a request message to the AP MLD for link change or reconnection without requesting additional information from the AP MLD. The request message can include AP information and link information to which the STA will reconnect. If the AP MLD receives the request message, it can send an "Accept" response message if it accepts the request, or a "Decline" response message if it rejects the request.

[0292] If the request is accepted, the AP can perform frame exchange with the reselected AP via the link after sending the response message. If the request is rejected, the STA can continue to use the existing connected link.

[0293] A specific example of AP MLD and non-AP MLD operations according to the general method will be described with reference to FIG.

[0294] FIG. 24 shows the operation of AP MLD and non-AP MLD for link change or reconnection.

[0295] 24, STA2 may directly desire to change the link for QoS guarantee reasons. If STA2 already has information received from AP MLD (e.g., information received via a Beacon frame or a Management frame, etc.) or has already determined the link it desires to reconnect to, STA2 may request a link change or reconnection without a separate information request.

[0296] STA2 can send a Link switching request frame including STA information (e.g. STA ID, etc.) and Link information to be changed (e.g. Link ID or AP BSS information, etc.). If the AP MLD that receives this approves the change, it can send an "approval" Link switching Response frame to STA3 via the existing Link2. After that, the non-AP MLD STA2 executes the Link(re)setup process and reconnects to AP3.

[0297] Signaling for indicating link changes and reconnection methods

[0298] In order to indicate the above proposed method, a mutual agreement process may be required through negotiation between AP MLD and non-AP MLD. Therefore, in the following specification, a signaling method for enabling the proposed method is proposed.

[0299] First, a new element is proposed to indicate the above proposed method. In the following, an embodiment related to signaling for indicating a link change and reconnection method is described, but the above embodiment is also applied to an embodiment related to signaling for indicating an anchored link change and reconnection method.

[0300] The signaling process for indicating the link change and reconnection method can be performed during or after the multi-link setup. In addition, the signaling process for indicating the link change and reconnection method uses new elements proposed below. For example, the elements are included in the (re)association frame of the conventional standard or the new frame.

[0301] IOM (Information Obtain Method) Capability Element

[0302] The IOM capability element can include information on whether to enable the method of obtaining additional information for multi-link. For example, in the process in which AP MLD and non-AP MLD exchange messages for operational agreement in the multi-link setup process (e.g., capability negotiation process), the IOM capability value can be present in the message element. The presence of the IOM capability value in the message element means that the IOM capability is supported.

[0303] According to one embodiment, if an AP MLD supports the IOM capability, the AP can internally share information about other APs and have information about other APs. An MLD in which information about other APs is not shared cannot support the IOM capability.

[0304] According to one embodiment, when the value of the IOM capability element is set as a first value (e.g., 1), the IOM capability element indicates that the IOM is to be activated to operate with the indicated functionality, and conversely, when the value of the IOM capability element is set as a second value (e.g., 0), the IOM capability element indicates that the IOM is to be deactivated.

[0305] According to an embodiment, the IOM capability element may include various fields / elements to indicate various operations. For example, the IOM capability element may include various fields / elements described below. However, the fields / elements added to the IOM capability element are set differently depending on whether an AP MLD requests a link change or a non-AP MLD requests a link change. Also, at least some of the fields / elements added to the IOM capability element are omitted. As an example, among the fields / elements added to the IOM capability element, a field / element including information that does not need to be indicated may be omitted.

[0306] The following describes examples of various fields / elements that are defined / configured to obtain additional information regarding the multilink. The various fields / elements described below may be configured independently, or two or more fields / elements may be combined and transmitted through various frames. For example, the various fields / elements described below may be included in another element and may perform the operations defined therein. In another example, the various fields / elements described below may be used in addition to each element or an independent field in another element.

[0307] Method type (or Method) field / element

[0308] The Method type field / element (hereinafter referred to as Method field / element) can include information about the operation method of the IOM. In other words, the Method field / element can indicate the operation method of the IOM. For example, when a non-AP MLD activates an IOM method to obtain information from an AP, the non-AP MLD can select and indicate the method to be used from among the methods proposed above (e.g., Solicited method, Unsolicited method, General method).

[0309] As an example, if the value of the Method field / element is a first value (e.g., 0), the Solicited method is indicated / used. If the value of the Method field / element is a second value (e.g., 1), the Unsolicited method is indicated / used. If the value of the Method field / element is a third value (e.g., 2), the General method is indicated / used. If the value of the Method field / element is a fourth value (e.g., 3), both the Solicited and Unsolicited methods are indicated / used.

[0310] As another example, one bit is used in the Method field / element. In this case, the Solicited method is indicated / used based on the value of the Method field / element being a first value (e.g., 0) (e.g., 0). The Unsolicited method is indicated / used based on the value of the Method field / element being a second value (e.g., 1).

[0311] As another example, 2 bits are used in the Method field / element. In this case, each method is specified to be used alone or in combination.

[0312] Info range field / element

[0313] The Info range field is used to indicate the range of the information when a non-AP MLD requests information (or when an IOM provides information to a non-AP MLD).

[0314] For example, if the value of the Info range field is a first value (e.g., 0), the Info range field may indicate that only some of the information possessed by the AP is provided, and if the value of the Info range field is a second value (e.g., 1), the Info range field may indicate that all of the information possessed by the AP (or all of the information) is provided.

[0315] According to one embodiment, an information range field is defined to indicate a request for all or part of information elements held by the AP, and the STA may request more detailed information via an additional subfield. For example, a subfield for indicating the range of information to be provided (e.g., all information or partial information) is included in the information range field. For example, the subfield for indicating the range of information to be provided is defined / set to the all / partial subfield.

[0316] According to one embodiment, a subfield is newly proposed to indicate whether all information is provided or only changed information among all the information is provided. In other words, the newly proposed subfield can indicate whether all information is provided or only changed information among all the information is provided.

[0317] For example, a subfield for indicating whether all information is provided or whether only changed information among all the information is provided is defined / set to the only updated subfield.

[0318] If a STA wishes to receive only changed information, the only updated subfield value is set to 1. In other words, if a STA wishes to receive only changed information, the STA can set the only updated subfield value to 1. For example, if the only updated subfield value is set to 1, according to the solicited method, when a STA requests information, the AP (or AP MLD) can transmit only changed information (i.e., updated information) among the requested information. In another example, if the only updated subfield value is set to 1, according to the unsolicited method, the AP can notify only information that has changed within the information range set by the STA.

[0319] In the above example, the only updated subfield in the info range field is proposed to receive only changed information, but this is not limiting. A separate field or element may be defined / set to receive only changed information.

[0320] According to the above embodiment, the range of information that the STA can request is set to updated information or all information. In this case, the STA that does not want a lot of frame overhead can request to receive only the changed information. Therefore, the overhead can be reduced.

[0321] Link condition field / element

[0322] The Link Condition field is used to indicate the specific link being requested. In other words, the Link Condition field can contain information about the specific link being requested. The Link Condition field is used when the STA only wants to receive specific link information from the AP.

[0323] The Link condition field can be represented by a link identifier (eg. Link ID, BSS ID). In other words, the Link condition field can contain information about a link identifier (eg. Link ID, BSS ID). In other words, the link identifier is used to specify the link for which information is to be obtained. When necessary, the "number of links" field may be used together to indicate the total number of link identifiers requested by the STA.

[0324] For example, if a STA connected to Link 1 wishes to request only information on Link 2 and Link 3 from the AP, the STA can display link 2 and link 3 in the link condition field to request information on Link 2 and Link 3 from the AP. For example, when the value of the above-mentioned Info range field is 1, all information corresponding to link 2 and link 3 is transmitted. In another example, when the value of the above-mentioned Info range field is 0, some information designated by the STA in link 2 and link 3 is transmitted. According to one embodiment, the part of information designated by the STA is determined via the Info condition field as follows:

[0325] According to one embodiment, if the value of the Link condition field is absent or 0, the AP may determine that there is no link condition. Therefore, the AP may provide / send information about all links to the STA.

[0326] At this time, if a STA wishes to request link information for all APs in the connected AP MLD, the following additional options are proposed. The first is to include the link identifiers for all APs in the "Link condition" field and make a request. The second is to have the "all / partial" field as a subfield in the "Link condition" field. At this time, the "all / partial" field is an indicator that indicates whether the link condition currently requested by the STA is information for all APs or for some APs. For example, when the "all / partial" field is 1, it means that information is requested for all APs in the connected AP MLD, and when the "all / partial" field is 0, it means that information is requested for some APs in the connected AP MLD. If information for some APs is requested, information on the link identifier for which AP information is requested must be provided. The third is to omit the "Link condition" field. If the "Link condition" field is sent with the "Link condition" field omitted, the AP MLD receives this as an example of an information request for all APs. In 802.11be, information for some APs can be requested using multiple options as shown above.

[0327] However, when a STA requests link information for all APs in the connected AP MLD as in the above case, the AP MLD responds with only information on the currently set up AP. For example, if the AP MLD has a total of five APs (AP1 to AP5) and is set up with a non-AP MLD and only three links (AP1 to AP3), when an information request message for all APs is received from a STA in the non-AP MLD, the AP MLD responds with only information on the set up links (AP1 to AP3).

[0328] Info condition field / element

[0329] The Info condition field is used to indicate the specific type of information requested. In other words, the Info condition field is used when the STA wishes to receive only specific information from the AP.

[0330] For example, the Info Condition field is used only if the Info Range field is set as 0. In another example, the Info Condition field is used by the STA to indicate specific information even if the Info Range field is not present.

[0331] For example, in the information condition field, information that the STA can specify (eg, BSS load, STR capability, etc.) can be expressed as a bitmap. For example, the type of information provided by the AP and the method or procedure of indicating the information in the bit can be set in various ways.

[0332] According to one embodiment, the information condition field is used together with the above-mentioned link condition field. According to one embodiment, the information condition field can transmit request information of various conditions to the STA (or AP) based on the combination of various fields / elements.

[0333] In this regard, the STA can reuse elements of existing standards to request specific information. For example, Request IE or Extended Request IE can be used. The corresponding element information is shown in FIG. 25 and FIG. 26.

[0334] FIG. 25 shows an example of the Request IE format.

[0335] FIG. 26 shows an example of the Extended Request IE format.

[0336] The elements in Figs. 25 and 26 are used to request specific information in a Probe Request frame or an Information Request frame. If the STA specifies a list of information to which it wishes to respond in the requested element IDs, the AP transmits the corresponding information in a Probe Response frame or an Information Response frame. Therefore, this element can be reused as an indicator for requesting specific information in this specification, and can also be used to request necessary information of a desired link together with a link identifier (e.g., Link identifier). For example, when an element ID for BSS load information is specified in the Request element mentioned in Figs. 28 and 29 to request information on AP2, when the Link identifier is specified, only the BSS load information of AP2 can be requested. Such element ID information is used to specify specific information of a specific AP in various combinations together with the Link identifier information. If a new frame for an information request that is not an existing frame is defined in the present invention, the Request element and Extended Request element in Figs. 25 and 26 can be reused.

[0337] Also, in the existing standard, when a PV 1 Probe Response Option element is provided to request specific information, such an element can be reused in a way that indicates specific information. The STA indicates each piece of information in the Probe response option bitmap as follows for frequently used information in a way that the STA uses to request optional information in a Probe Request. However, in the case of 802.11be, since it is necessary to provide multi-link information in consideration of MLD, the STA can request specific information of specific links in various combinations by using a link identifier together with a bitmap indicator as follows. However, in this case, since there may be optional information (e.g. STR capability) newly defined along with multi-link in 802.11be, if this PV 1 Probe Response Option element is reused, a bitmap for information that is newly defined or needs to be acquired in 802.11be must be newly defined or additionally defined.

[0338] FIG. 27 shows an example of the PV 1 Probe Response Option element format.

[0339] Transmission periodic field / element

[0340] If a STA wishes to provide information in an unsolicited manner, it can indicate via a transmission periodic field whether it will receive a message including the information periodically or aperiodically.

[0341] For example, if the STA wishes to receive the information non-periodically, the AP can notify the STA of the updated information every time an update occurs to the information of other APs.

[0342] In another example, when the STA instructs to receive the information periodically, the STA can receive a message including the information at periodic intervals set by the STA.

[0343] According to one embodiment, the transmission periodicity field is set to 1 bit. When the value of the transmission periodicity field is set as 1, the STA can receive / acquire information via a periodic method of periodically receiving messages. When the value of the transmission periodicity field is set as 0, the STA can receive / acquire information via a method of aperiodically receiving messages.

[0344] Transmission interval field / element

[0345] According to an embodiment, if a STA wants to receive information about other APs periodically, the STA can directly set the interval. The STA can transmit information about the interval for receiving other AP information based on the transmission interval field. However, the interval needs to be set shorter than the beacon transmission interval. For example, if a FILS discovery frame is used, the interval needs to be set to 20 us.

[0346] As described above, it is defined as a separate field in an element that indicates the transmission period, or it is also defined as a subfield in a transmission periodic field.

[0347] According to an embodiment, the fields / elements defined / set to obtain additional information regarding the multilink are not limited to the above-mentioned fields / elements, and various fields / elements may be further set.

[0348] Therefore, MLD (AP MLD or non-AP MLD) can indicate IOM capability through negotiation between AP MLD and non-AP MLD using at least one of the above elements / fields in the multi-link setup process. Also, MLD can update the agreement between MLDs through separate message exchange after multi-link setup is completed.

[0349] According to one embodiment, when the IOM capability is activated, AP MLD and non-AP MLD can operate according to an embodiment for link change and reconnection.

[0350] In the following, examples of the operation of AP MLD and non-AP MLD when IOM capability is activated are described. For example, the non-AP MLD can request additional information for multilink by sending the above-mentioned field / element to the AP MLD. The non-AP MLD can send an IOM capability element including the above-mentioned field / element to the AP MLD. The above-mentioned field / element is included in the IOM capability element for illustrative purposes only, and is sent in an independent field / element.

[0351] For example, in the multi-link setup process, the non-AP MLD can send an IOM capability element including "Method field=0" and "Info range field=1" to the AP MLD and agree on this with the AP MLD. In this case, after the multi-link setup, the non-AP MLD operates in the Solicited method and can request information for the multi-link (e.g., information about other APs) including all information included in the beacon when requesting information. Therefore, the AP MLD can provide / send information about the link in a response message only when it receives a request message from the STA. When the AP MLD receives a request message, it can send a response message including information about all links in the AP MLD to the STA. The information about all links in the AP MLD can include all information included in the beacon.

[0352] In another example, the non-AP MLD can send an IOM capability element including "Method field=1", "Info range field=0", "Link range=Link ID2", and "Info condition field=(value indicating BSS load via bitmap)" to the AP MLD and agree on this with the AP MLD. In this case, after multi-link setup, the non-AP MLD can operate in the UnSolicited method. Therefore, the AP can send the BSS load information of Link2 to the STA via a separate message without a separate request message.

[0353] In another example, the non-AP MLD can send an IOM capability element including "Method field=0", "Info range field=0", "only updated field or subfield=1", and "Info condition field=(value indicating BSS load via bitmap)" to the AP MLD and agree on this with the AP MLD. In this case, after multi-link setup, the non-AP MLD can operate in the Solicited method. Therefore, the AP MLD (or AP) can send only the updated (changed) information of the BSS load information of all APs in the AP MLD connected when the STA requests information to the STA in a response message.

[0354] AP MLD and non-AP MLD can activate the proposed IOM method via the signaling method proposed in this specification during or after the multi-link setup process, and can restrict the scope and type of information they request via various field values ​​in the IOM capability element.

[0355] In this way, in the standard, IOM operation may be performed after precise operation negotiation between MLDs through such an IOM signaling method, but in this specification, the case where the IOM method operates by MLD implementation without a separate signaling process is also considered. This means that it operates by AP MLD implementation or non-AP MLD implementation without negotiation between AP MLD and non-AP MLD.

[0356] Generally, the operation can be performed as proposed above, however, if the MLD performs IOM operation without a separate signaling exchange, the following restrictions may occur.

[0357] 1) Restrictions on the Solicited Method: If info sharing is not supported between APs in AP MLD, a STA cannot respond when it requests information for another link.

[0358] 2) Restrictions on the Unsolicited Method: The AP determines which STAs require additional link information and provides them with a separate message (e.g., beacon period, etc.). Therefore, the STAs cannot predict in advance whether they will receive this information.

[0359] If MLD implements IOM without a separate signaling method, the operation process can be simplified, but there may be the limitations mentioned above.

[0360] The method proposed in this specification can be set based on the agreement between AP MLD and non-AP MLD using the "IOM capability" element mentioned above. However, in the case of the Solicited method, if a STA specifies specific information other than the agreed content and wishes to temporarily acquire that information, the STA can dynamically request the specified content (e.g., IOM capability information) when sending a Request message.

[0361] During or after Multi-Link setup, the AP may provide information to the STA based on the contents agreed upon by the AP MLD and non-AP MLD, but if the STA wishes to temporarily request information on a specific AP or specific parameter information on an AP, it can send an instruction for the information it wishes to request using the "IOM capability" element in the information request frame (e.g., Probe Request frame, reassociation frame, or new frame, etc.), and the AP can provide a response message including information based on that information value. If the field in the IOM capability element is omitted, the AP provides information based on the existing agreed contents.

[0362] Therefore, the MLD agrees on the information provided through negotiation between the AP MLD and non-AP MLD using the above elements during or after the multi-link setup process, and receives the information. Alternatively, the MLD can receive only the temporarily requested information by sending a request message from the STA including instructions for the information it wishes to request. However, if the STA omits special instructions in the request message, it operates according to the instructions that were basically agreed upon. If the agreement needs to be changed after the completion of the multi-link setup, the agreement between the MLDs can be updated through a separate message exchange.

[0363] How to request changed Critical update information

[0364] In this specification, a method is proposed in which a non-AP MLD STA requests some information of an affiliated AP in an AP MLD, but this method is used specifically to allow a STA to obtain only changed critical update information.

[0365] First, a STA uses a "Change sequence" element (or field) and a link indicator (e.g. Link ID or BSS ID) in a request frame (e.g. Probe Request frame) to request some information from an affiliated AP in the AP MLD. In 802.11ah, when a "Change sequence" element is included in a Probe Request frame and sent, the Probe response responds with a compressed Probe response that includes only the updated values ​​in the current Critical update list. This method can be reused in 802.11be to allow a STA to obtain only the changed Critical update information from an AP. For example, if a non-AP MLD STA sends a Probe Request including a Chance sequence element, the AP that receives it responds with a Probe response that includes only the changed values ​​in the Critical update. In this case, the STA can propose four operation options in 802.11be in response to a request frame transmission that includes a Change sequence element.

[0366] 1) When a STA sends a request frame including a Change sequence element, the AP that receives it provides change information of its own Critical update. For example, if STA1 of non-AP MLD includes a Change sequence element in a Probe Request and sends it to an AP (however, in this case, it is sent without a separate link indicator), AP1 that receives it responds by including the change value of its own Critical update in a Probe Response frame.

[0367] 2) When a STA sends a request frame including a Change sequence element (however, in this case, it is sent without a separate link indicator), the AP that receives it provides information on all APs in the AP MLD it is included in. For example, if STA1 in a non-AP MLD sends a Probe Request including a Change sequence element to an AP, AP1 that receives it responds by including the changed values ​​of the Critical updates of all APs (e.g. AP1, 2, 3) in the AP MLD to which it is connected in a Probe Response frame.

[0368] 3) When a STA transmits a Change sequence element including a Link identifier (e.g., Link ID or BSS ID), the AP that receives the Change sequence element responds by including all the changed values ​​of the Critical update for the link that corresponds to the specified Link identifier. For example, when STA1 of a non-AP MLD transmits a Probe Request to an AP with a Change sequence element specifying AP1 and 2 as the Link identifier (assuming that the AP MLD has AP1, 2, and 3), the AP responds by including only the changed values ​​of the Critical update for AP1 and 2 in the Probe Response frame.

[0369] 4) When a STA sends a request frame including a Change sequence element and an "all / part" field (an indicator that indicates whether the requested information refers to all APs in the connected AP MLD or some of the APs), the STA responds with all or some of the information in the response depending on the "all / part" field value. For example, if a STA sends a Probe Request frame with a Change sequence element and an "all / part" field value of 1 (indicating an information request for all APs), the AP that receives this responds with a Probe response that includes the Critical update change value for all APs in the connected AP MLD. Or, if a STA sends a Probe Request frame with a Change sequence element and an "all / part" field value of 0 (indicating an information request for some APs), the AP that receives this responds with a Probe response that includes the Critical update change value for some APs in the connected AP MLD. In this case, the STA needs to send a Link identifier (Link ID or BSS ID) that indicates which AP's information is requested.

[0370] The second method is to use an 'updated only' field (a newly defined field in this specification) and a link indicator (e.g. Link ID or BSS ID) in a request frame (e.g. Probe Request frame) in which the STA requests some information from an affiliated AP in the AP MLD. When the STA sends a request frame requesting information from the AP with the 'updated only' field value set to 1, the AP responds with only the updated information in its Critical update value. The advantage is that it can be indicated in a simple 1-bit field without adding a separate element. In this case, the STA can propose four operation options in 802.11be when sending a request frame including the 'updated only' field.

[0371] 1) When a STA sends a request frame with the 'updated only' field value set to 1, the AP that receives it provides the change information of its own Critical update. When a STA sends a request frame with the 'updated only' field value set to 0, the AP that receives it provides the current information of its current Critical update (i.e., provides all information including not only changed information but also unchanged information). For example, when a non-AP MLD STA sends a Probe Request to an AP with the 'updated only' field set to 1 (however, in this case, if it is sent without a separate link indicator), the AP that receives it responds by including only the change value of its own Critical update in the Probe Response frame.

[0372] 2) When a STA sends a request frame including the 'updated only' field (however, in this case, it is sent without a separate link indicator), the AP that receives it provides information on all APs in the AP MLD it is included in. For example, if STA1 in a non-AP MLD sets the 'updated only' field value to 1 in a Probe Request and sends it to an AP, AP1 that receives it responds by including the changed values ​​of the Critical updates of all APs (e.g. AP1, 2, 3) in the AP MLD to which it is connected in a Probe Response frame.

[0373] 3) When a STA transmits a link identifier (e.g., link ID or BSS ID) together with the "updated only" field, the AP that receives the transmission responds by including all the changed values ​​of the critical update for the link corresponding to the specified link identifier. For example, when STA1 of a non-AP MLD transmits a Probe Request to an AP with the "updated only" field=1 and specifying AP1 and 2 in the link indicator (assuming that the AP MLD has AP1, 2, and 3), the AP responds by including only the changed values ​​of the critical update for AP1 and 2 in the Probe Response frame.

[0374] 4) When a STA transmits a request frame including an "updated only" field and an "all / part" field (an indicator indicating whether the requested information refers to all APs in the connected AP MLD or some of the APs), the STA responds with all or some of the information in the response depending on the "all / part" field value. For example, when a STA transmits a Probe Request frame with an "updated only" field set to 1 and an "all / part" field value set to 1 (indicating an information request for all APs), the AP that receives this responds with a Probe response including the Critical update change value for all APs in the connected AP MLD. Or, when a STA transmits a Probe Request frame with an "updated only" field set to 1 and an "all / part" field value set to 0 (indicating an information request for some APs), the AP that receives this responds with a Probe response including the Critical update change value for some APs in the connected AP MLD. In this case, the STA needs to transmit a Link identifier (Link ID or BSS ID) that can indicate which AP's information is requested.

[0375] We also propose a method in which a STA requests information on other APs in the MLD of the connected AP (or information on all links in the MLD of the connected AP) using an ML (Multi-Link) element defined in the 802.11be standard.

[0376] FIG. 28 shows an example of the ML element format defined in 802.11be.

[0377] In 802.11be, ML elements are defined as shown in the upper part of Figure 28 to define information for each link. Elements or fields are added according to the proposed functions. The ML elements can include an Element ID field, a Length field, an Element ID Extension field, a Multi-Link Control field, a Common Info field, and a Link Info field.

[0378] The bottom part of FIG. 28 shows the Multi-Link Control field.

[0379] The Multi-Link Control field includes a Type subfield, which is defined as follows and is used to distinguish different variants of the ML element, which are used for different multi-link operations.

[0380] [Table 1]

[0381] The Multi-Link Control field further includes a Presence Bitmap subfield, which is used to indicate the presence of various subfields in the Common Info field.

[0382] The Common Info field transmits information common to all links except for the Link ID Info subfield and the BSS Parameters Change Count subfield for the link through which the Multi-Link element is transmitted, and is selectively present depending on the value of the Type subfield.

[0383] The Common Info field is composed of zero or more subfields whose presence is indicated by the subfields of the Multi-Link Control field. The subfields of the Common Info field are indicated in the same order as the corresponding subfields of the Multi-Link Control field.

[0384] The Link Info field conveys link specific information and is selectively present based on the value of the Type subfield.

[0385] The Probe Request variant Multi-Link element is used to request that an AP provide information about another AP that is in the same AP MLD as the AP. The inclusion of the Probe Request variant Multi-Link element in a Probe Request frame identifies it as an ML Probe Request.

[0386] The Link Info field includes zero or more Per-STA Profile subelements.

[0387] FIG. 29 shows the Per-STA Profile subelement of the Probe Request variant Multi-Link element.

[0388] Referring to the top of FIG. 29, the Per-STA Profile subelement of the Probe Request variant Multi-Link element includes a Subelement ID field, a Length field, a STA Control field, and a STA Profile field.

[0389] The bottom part of Figure 29 shows the STA Control field, which includes a Link ID subfield, a Complete Profile subfield, and a reserved field.

[0390] The Link ID subfield specifies a value that uniquely identifies the AP for which information is requested.

[0391] The Complete Profile subfield is set to 1 when requesting complete information from the AP. Otherwise, the Complete Profile subfield is set as 0.

[0392] The STA Profile field of the Per-STA Profile subelement contains only an (Extended) Request element if a non-AP STA requests partial information from an AP corresponding to the per-STA Profile, and is not present if the non-AP STA requests complete information from the AP.

[0393] In the following, the above-mentioned embodiments will be described with reference to FIGS.

[0394] FIG. 30 is a flow diagram showing a procedure in which a sending MLD according to this embodiment provides information on an AP contained in the sending MLD to a receiving MLD based on a probe response frame.

[0395] The example of Fig. 30 can be executed in a network environment in which a next-generation wireless LAN system (IEEE 802.11be or EHT wireless LAN system) is supported. The next-generation wireless LAN system can meet backward compatibility with the 802.11ax system as a wireless LAN system that improves the 802.11ax system.

[0396] This embodiment proposes a method and apparatus for a STA of a receiving MLD to request information on all or some of the links of a transmitting MLD in MLD communication. The transmitting MLD may be an AP MLD, and the receiving MLD may be a non-AP MLD.

[0397] In step S3010, a transmitting MLD (Multi-link Device) receives a probe request frame from a receiving MLD via a first link.

[0398] In step S3020, the transmitting MLD transmits a probe response frame to the receiving MLD via the first link.

[0399] As an example, the transmitting MLD includes a first transmitting STA (station) operating in the first link, a second transmitting STA operating in the second link, and a third transmitting STA operating in the third link. The receiving MLD includes a first receiving STA operating in the first link. The receiving MLD may further include a second receiving STA operating in the second link, and a third receiving STA operating in the third link.

[0400] When the first receiving STA requests information on the second and third links, the probe request frame includes link identifiers for the second and third links. That is, when the first receiving STA desires to receive only information on a specific link from the first transmitting STA, the probe request frame can include the link identifier for the specific link to indicate the required information.

[0401] However, when the first receiving STA requests information on all links, the probe request frame does not include link identifiers for all links. Conventionally, when the first receiving STA requests information on all links, the probe request frame needs to include identifiers for all links, which causes a problem of large overhead. On the other hand, in the present embodiment, when the first receiving STA requests information on all links, it is not necessary to include identifiers for all links (by omitting or removing identifiers for all links), which has the effect of reducing frame overhead.

[0402] The probe request frame may include an information range field and an information condition field.

[0403] The information range field may include information that the receiving MLD can provide. If the information range field is set to 1, the information that the receiving MLD can provide may be all information of the transmitting MLD. If the information range field is set to 0, the information that the receiving MLD can provide may be partial information or updated information of the transmitting MLD. All information of the transmitting MLD may be all information for a specific link indicated by a link identifier. The partial information or updated information of the transmitting MLD may also be partial information or updated information for a specific link indicated by a link identifier.

[0404] The information condition field may include information that the receiving MLD wishes to provide. If the information range field is set to 0, the information that the receiving MLD wishes to provide may be defined in a bitmap. Each bit of the bitmap may indicate information that the receiving MLD may specify. For example, assuming that the bitmap is composed of 6 bits, the first bit of the bitmap may represent BSS (Basic Service Set) load information for each AP, the second bit may represent STR (Simultaneous transmit and receive) capability information between links, the third bit may represent TXOP (Transmission Opportunity) information for each link, the fourth bit may represent NAV (Network Allocate Vector) information for each link, the fifth bit may represent recommended link information, and the sixth bit may represent connected STA ratio information for each link. In this case, if each bit is set to 1, the receiving MLD may request the corresponding information, and if each bit is set to 0, the receiving MLD may not request the corresponding information.

[0405] The probe request frame may further include a Change sequence element. If the probe request frame includes link identifiers for the second and third links, the Change sequence element is used to request critical update information for the second and third transmitting STAs. If the probe request frame does not include link identifiers for all of the links, the Change sequence element is used to request critical update information for all transmitting STAs in the transmitting MLD.

[0406] Also, the probe request frame may further include a newly defined updated only field instead of the changed sequence element, which is also used to request important updated information (changed information) of the sending MLD.

[0407] The probe response frame may include information that the receiving MLD can provide, information that the receiving MLD wants to provide, important update information of the second and third transmitting STAs, or important update information of all transmitting STAs in the transmitting MLD. That is, the first transmitting STA of the transmitting MLD can inform the first receiving STA of the information requested by the first receiving STA through the probe response frame.

[0408] The probe request frame may further include link indicator information. The link indicator information may include identifier information of the first, second, or third link. A profile field of the first receiving STA, a profile field of the second receiving STA, and a profile field of the third receiving STA are included in the probe request frame based on the link indicator information. For example, if the link indicator information includes identifier information of the first link, a profile field of the first receiving STA is included in the probe request frame. If the link indicator information includes identifier information of the second link, a profile field of the second receiving STA is included in the probe request frame.

[0409] FIG. 31 is a flow diagram showing a procedure in which a receiving MLD according to this embodiment requests information on an AP included in the transmitting MLD based on a probe request frame.

[0410] The example of Fig. 31 can be executed in a network environment in which a next-generation wireless LAN system (IEEE 802.11be or EHT wireless LAN system) is supported. The next-generation wireless LAN system can meet backward compatibility with the 802.11ax system as a wireless LAN system that improves the 802.11ax system.

[0411] This embodiment proposes a method and apparatus for a STA of a receiving MLD to request information on all or some of the links of a transmitting MLD in MLD communication. The transmitting MLD may be an AP MLD, and the receiving MLD may be a non-AP MLD.

[0412] In step S3110, a receiving MLD (Multi-link Device) transmits a probe request frame to a transmitting MLD via a first link.

[0413] In step S3120, the receiving MLD receives a probe response frame from the sending MLD via the first link.

[0414] As an example, the transmitting MLD includes a first transmitting STA (station) operating in the first link, a second transmitting STA operating in the second link, and a third transmitting STA operating in the third link. The receiving MLD includes a first receiving STA operating in the first link. The receiving MLD may further include a second receiving STA operating in the second link, and a third receiving STA operating in the third link.

[0415] When the first receiving STA requests information on the second and third links, the probe request frame includes link identifiers for the second and third links. That is, when the first receiving STA desires to receive only information on a specific link from the first transmitting STA, the probe request frame can include the link identifier for the specific link to indicate the required information.

[0416] However, when the first receiving STA requests information on all links, the probe request frame does not include link identifiers for all links. Conventionally, when the first receiving STA requests information on all links, the probe request frame needs to include identifiers for all links, which causes a problem of large overhead. On the other hand, in the present embodiment, when the first receiving STA requests information on all links, it is not necessary to include identifiers for all links (by omitting or removing identifiers for all links), which has the effect of reducing frame overhead.

[0417] The probe request frame may include an information range field and an information condition field.

[0418] The information range field may include information that the receiving MLD can provide. If the information range field is set to 1, the information that the receiving MLD can provide may be all information of the transmitting MLD. If the information range field is set to 0, the information that the receiving MLD can provide may be partial information or updated information of the transmitting MLD. All information of the transmitting MLD may be all information for a specific link indicated by a link identifier. The partial information or updated information of the transmitting MLD may also be partial information or updated information for a specific link indicated by a link identifier.

[0419] The information condition field may include information that the receiving MLD wishes to provide. If the information range field is set to 0, the information that the receiving MLD wishes to provide may be defined in a bitmap. Each bit of the bitmap may indicate information that the receiving MLD may specify. For example, assuming that the bitmap is composed of 6 bits, the first bit of the bitmap may represent BSS (Basic Service Set) load information for each AP, the second bit may represent STR (Simultaneous transmit and receive) capability information between links, the third bit may represent TXOP (Transmission Opportunity) information for each link, the fourth bit may represent NAV (Network Allocate Vector) information for each link, the fifth bit may represent recommended link information, and the sixth bit may represent connected STA ratio information for each link. In this case, if each bit is set to 1, the receiving MLD may request the corresponding information, and if each bit is set to 0, the receiving MLD may not request the corresponding information.

[0420] The probe request frame may further include a Change sequence element. If the probe request frame includes link identifiers for the second and third links, the Change sequence element is used to request critical update information for the second and third transmitting STAs. If the probe request frame does not include link identifiers for all of the links, the Change sequence element is used to request critical update information for all transmitting STAs in the transmitting MLD.

[0421] Also, the probe request frame may further include a newly defined updated only field instead of the changed sequence element, which is also used to request important updated information (changed information) of the sending MLD.

[0422] The probe response frame may include information that the receiving MLD can provide, information that the receiving MLD wants to provide, important update information of the second and third transmitting STAs, or important update information of all transmitting STAs in the transmitting MLD. That is, the first transmitting STA of the transmitting MLD can inform the first receiving STA of the information requested by the first receiving STA through the probe response frame.

[0423] The probe request frame may further include link indicator information. The link indicator information may include identifier information of the first, second, or third link. A profile field of the first receiving STA, a profile field of the second receiving STA, and a profile field of the third receiving STA are included in the probe request frame based on the link indicator information. For example, if the link indicator information includes identifier information of the first link, a profile field of the first receiving STA is included in the probe request frame. If the link indicator information includes identifier information of the second link, a profile field of the second receiving STA is included in the probe request frame.

[0424] The technical features of the present specification described above can be applied to various devices and methods. For example, the technical features of the present specification described above are performed / supported via the device of FIG. 1 and / or FIG. 11. For example, the technical features of the present specification described above are applied to only a part of FIG. 1 and / or FIG. 11. For example, the technical features of the present specification described above are implemented based on the processing chips 114 and 124 of FIG. 1, or based on the processors 111 and 121 and memories 112 and 122 of FIG. 1, or based on the processor 610 and memory 620 of FIG. 11. For example, the device of the present specification transmits a probe request frame to a transmitting MLD via a first link and receives a probe response frame from the transmitting MLD via the first link.

[0425] The technical features of the present specification are implemented based on a CRM (computer readable medium). For example, the CRM proposed by the present specification is at least one computer readable medium including instructions based on being executed by at least one processor.

[0426] The CRM may store instructions for performing operations including: transmitting a probe request frame to a transmitting MLD via a first link; and receiving a probe response frame from the transmitting MLD via the first link. The instructions stored in the CRM herein are executed by at least one processor. The at least one processor associated with the CRM herein may be the processors 111, 121 or processing chips 114, 124 of FIG. 1, or the processor 610 of FIG. 11. Meanwhile, the CRM herein may be the memory 112, 122 of FIG. 1, the memory 620 of FIG. 11, or a separate external memory / storage medium / disk, etc.

[0427] The technical features of the present specification described above can be applied to various applications and business models. For example, the technical features described above can be applied to wireless communication in a device that supports artificial intelligence (AI).

[0428] Artificial intelligence refers to the field that studies artificial intelligence or the methodology for creating it, while machine learning refers to the field that defines various problems to be dealt with in the field of artificial intelligence and studies the methodology for solving them. Machine learning can also be defined as an algorithm that improves its performance for a certain task through continuous experience with that task.

[0429] Artificial neural network (ANN) is a model used in machine learning that is composed of artificial neurons (nodes) that form a network of synaptic connections and has problem-solving capabilities. An artificial neural network is defined by the connection patterns between neurons in different layers, the learning process that updates the model parameters, and the activation function that generates the output values.

[0430] An artificial neural network can include an input layer, an output layer, and optionally one or more hidden layers. Each layer includes one or more neurons, and an artificial neural network can include synapses that connect the neurons. In an artificial neural network, each neuron can output a function value of an activation function in response to input signals, weights, and biases input via synapses.

[0431] Model parameters are parameters that are determined through learning, including synaptic connection weights and neuron biases, while hyperparameters are parameters that must be set before learning in machine learning algorithms, including the learning rate, number of iterations, mini-batch size, and initialization function.

[0432] The goal of training an artificial neural network is to determine the model parameters that minimize a loss function. The loss function is used as an index to determine the optimal model parameters in the training process of an artificial neural network.

[0433] Depending on the learning method, machine learning can be classified as supervised learning, unsupervised learning, and reinforcement learning.

[0434] Supervised learning refers to a method of training an artificial neural network when labels for training data are given, and refers to the correct answer (or result value) that the artificial neural network needs to infer when training data called labels are input to the artificial neural network. Unsupervised learning refers to a method of training an artificial neural network when labels for training data are not given. Reinforcement learning refers to a learning method in which an agent defined in an environment is trained to select an action or sequence of actions that maximizes cumulative reward in each state.

[0435] Among artificial neural networks, machine learning implemented as a deep neural network (DNN) containing multiple hidden layers is also called deep learning, and deep learning is a part of machine learning. In the following, machine learning is used to include deep learning.

[0436] The above-mentioned technical features are also applicable to wireless communication of robots.

[0437] A robot is a machine that performs or automatically performs tasks given to it using its own capabilities. In particular, a robot that can recognize its environment, make its own decisions, and execute its actions is called an intelligent robot.

[0438] Robots can be classified into industrial, medical, domestic, military, etc., depending on the purpose and field of use. Robots have a driving part including an actuator or a motor, and can perform various physical actions such as moving the robot joints. Mobile robots also have a driving part including wheels, brakes, propellers, etc., and can run on the ground or fly in the air via the driving part.

[0439] The above technical features also apply to devices that support augmented reality.

[0440] Augmented reality is a general term for virtual reality (VR), augmented reality (AR), and mixed reality (MR). VR technology provides real-world objects and backgrounds only as CG images, AR technology provides virtual CG images on top of images of real objects, and MR technology is a computer graphics technology that mixes and combines virtual objects into the real world.

[0441] MR technology is similar to AR technology in that it shows virtual objects together with virtual objects, but the difference is that in AR technology, virtual objects are used to complement virtual objects, while in MR technology, virtual objects and virtual objects are used with equal characteristics.

[0442] XR technology is applied to HMDs (Head-Mount Displays), HUDs (Head-Up Displays), mobile phones, tablet PCs, laptops, desktops, TVs, digital signage, etc., and devices to which XR technology is applied can be called XR devices.

[0443] The claims described herein may be combined in various ways, for example, the technical features of the method claims herein may be combined and implemented in an apparatus, the technical features of the device claims herein may be combined and implemented in a method, the technical features of the method claims herein and the technical features of the device claims herein may be combined and implemented in an apparatus, and the technical features of the method claims herein and the technical features of the device claims herein may be combined and implemented in a method.

Claims

1. 1. A method in a wireless local area network (WLAN) system, the method comprising: A first non-AP (non-access point) STA (station) transmits a probe request frame to a first AP; receiving a probe response frame from the first AP by the first non-AP STA; The first AP operating in the first link, the second AP operating in the second link, and the third AP operating in the third link are affiliated with an AP MLD (multi-link device); the first non-AP STA operating in the first link is affiliated with a non-AP MLD; Based on the probe request frame including information for the second AP and the third AP, only APs whose link IDs are equal to values ​​in Link ID fields in the information for the second AP and the third AP in the probe request frame are the second AP and the third AP; The probe request frame permits the first non-AP STA to request information about all APs affiliated with the AP MLD based on the probe request frame not including any information about all APs.

2. The method of claim 1 , wherein the probe request frame includes an information scope field and an information condition field.

3. The information range field includes information that can be provided to the non-AP MLD, If the information range field is set to 1, the information that can be provided to the non-AP MLD is all information of the AP MLD; The method of claim 2 , wherein if the information range field is set to 0, the information that can be provided to the non-AP MLD is partial information or updated information of the AP MLD.

4. The information condition field includes information that the non-AP MLD wants to provide, If the information scope field is set to 0, the information to be provided by the non-AP MLD is defined as a bitmap. The method of claim 3 , wherein each bit of the bitmap indicates information that the non-AP MLD can specify.

5. The probe request frame further includes a modified sequence element; Based on the probe request frame including link identifiers for the second and third links, the modified sequence element is used to request important update information of the second and third APs; The method of claim 4 , wherein if the probe request frame does not include the link identifiers for all links, the change sequence element is used to request important update information of all APs in the AP MLD.

6. The method of claim 5, wherein the probe response frame includes the information that can be provided to the non-AP MLD, the information that the non-AP MLD wants to be provided, the important update information of the second and third APs, or the important update information of all APs in the AP MLD.

7. the non-AP MLD further includes a second non-AP STA operating in the second link and a third non-AP STA operating in the third link; The probe request frame further includes link indicator information; the link indicator information includes identifier information of the first, second or third link; The method of claim 1 , wherein a profile field of the first non-AP STA, a profile field of the second non-AP STA, and a profile field of the third non-AP STA are included in the probe request frame based on the link indicator information.

8. A first non-AP (non-access point) STA (station) in a WLAN (wireless local area network) system, the first non-AP STA comprising: Memory, A transceiver; a processor operatively coupled to the memory and the transceiver, the processor comprising: Sending a probe request frame to the first AP; configured to receive a probe response frame from the first AP; The first AP operating in the first link, the second AP operating in the second link, and the third AP operating in the third link are affiliated with an AP MLD (multi-link device); the first non-AP STA operating in the first link is affiliated with a non-AP MLD; Based on the probe request frame including information for the second AP and the third AP, only APs whose link IDs are equal to values ​​in Link ID fields in the information for the second AP and the third AP in the probe request frame are the second AP and the third AP; The probe request frame permits the first non-AP STA to request information regarding all APs affiliated with the AP MLD, based on the probe request frame not including any information regarding all APs.

9. 1. A method in a wireless local area network (WLAN) system, the method comprising: A first access point (AP) receives a probe request frame from a first non-AP station (STA); The AP MLD transmits a probe response frame to the first non-AP STA; The first AP operating in the first link, the second AP operating in the second link, and the third AP operating in the third link are affiliated with an AP MLD (multi-link device); the first non-AP STA operating in the first link is affiliated with a non-AP MLD; Based on the probe request frame including information for the second AP and the third AP, only APs whose link IDs are equal to values ​​in Link ID fields in the information for the second AP and the third AP in the probe request frame are the second AP and the third AP; The probe request frame permits the first non-AP STA to request information about all APs affiliated with the AP MLD based on the probe request frame not including any information about all APs.

10. The method of claim 9 , wherein the probe request frame includes an information scope field and an information condition field.

11. The information range field includes information that can be provided to the non-AP MLD, If the information range field is set to 1, the information that can be provided to the non-AP MLD is all information of the AP MLD; The method of claim 10, wherein if the information range field is set to 0, the information that can be provided to the non-AP MLD is partial information or updated information of the AP MLD.

12. The information condition field includes information that the non-AP MLD wants to provide, If the information scope field is set to 0, the information to be provided by the non-AP MLD is defined as a bitmap. The method of claim 11 , wherein each bit of the bitmap indicates information that the non-AP MLD can specify.

13. The probe request frame further includes a modified sequence element; If the probe request frame includes link identifiers for the second and third links, the modified sequence element is used to request important update information of the second and third APs; The method of claim 12 , wherein if the probe request frame does not include the link identifiers for all links, the change sequence element is used to request important update information of all APs in the AP MLD.

14. The method of claim 13, wherein the probe response frame includes the information that can be provided to the non-AP MLD, the information that the non-AP MLD wants to be provided, the important update information of the second and third APs, or the important update information of all APs in the AP MLD.

15. the non-AP MLD further includes a second non-AP STA operating in the second link and a third non-AP STA operating in the third link; The probe request frame further includes link indicator information; the link indicator information includes identifier information of the first, second or third link; The method of claim 9 , wherein a profile field of the first non-AP STA, a profile field of the second non-AP STA, and a profile field of the third non-AP STA are included in the probe request frame based on the link indicator information.

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