Technique for performing multi-link communication in wireless communication system

Abstract

To provide a device that supports multi-link.SOLUTION: According to various embodiments, a multi-link device (MLD) operating on multiple links including a first link transmits a request frame including an information field for requesting all elements included in an element set designated for a second link to a first AP of an AP multi-link device via a first station (STA). The multi-link device receives all elements included in the element set designated for the second link on the basis of the request frame.SELECTED DRAWING: Figure 29

Description

[Technical Field]

[0001] The present specification relates to a technique for performing multi-link communication in a wireless LAN system, and more particularly to a method for transmitting information about links in multi-link communication and an apparatus supporting the same. [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 orthogonal frequency division multiple access (OFDMA) and downlink multi-user multiple input, multiple output (DL MU MIMO) techniques.

[0003] This specification proposes technical features that can be utilized in a new communication standard. For example, the new communication standard may be the Extreme High Throughput (EHT) standard, which has recently been under discussion. The EHT standard may use newly proposed increased bandwidth, improved PHY layer protocol data unit (PPDU) structure, improved sequences, Hybrid Automatic Repeat Request (HARQ) techniques, etc. The EHT standard may be referred to as the IEEE 802.11be standard. Summary of the Invention [Problem to be solved by the invention]

[0004] The EHT standard may use wide bandwidth (eg, 160 / 320 MHz), 16 streams, and / or multi-link (or multi-band) operation to support high throughput and high data rates.

[0005] In the EHT standard, a device supporting multilink (i.e., a multilink device) can operate with multiple links. In order for a multilink device to change the connected link, it needs to receive information about other links that are not included in the multiple links. Therefore, a technical feature for receiving information about other links that are not connected to the multilink device may be required.

[0006] Furthermore, since a multilink device needs to receive information about at least one of the multiple links while performing communication over a first link, a technical feature for receiving information about other links in a multilink device may be required. [Means for solving the problem]

[0007] According to various embodiments, a multi-link device (MLD) operating on multiple links including a first link transmits a request frame including an information field for requesting all elements included in an element set specified for a second link to a first AP of an AP multi-link device via a first STA (Station) included in the multi-link device, and the first STA performs the steps of operating on the first link and receiving a response frame from the first AP via the first STA based on the request frame, the response frame including all elements included in the element set specified for the second link. [Effects of the Invention]

[0008] STAs included in a multi-link device can transmit information about other STAs in the multi-link device through one link, which reduces frame exchange overhead and increases link utilization efficiency of the STAs, thereby reducing power consumption.

[0009] In addition, a first STA included in a multilink device can request overall information for each link. For example, a first STA in a multilink device can request overall information for a second link and only partial information for a third link. Therefore, since the first STA can request overall information for each link, the AP multilink device can transmit overall information for the indicated links. [Brief explanation of the drawings]

[0010] [Figure 1] 1 illustrates an example of a transmitting device and / or a receiving device of the present specification. [Figure 2] FIG. 1 is a conceptual diagram showing the structure of a wireless RAN (WLAN). [Figure 3] FIG. 1 is a diagram illustrating a general link setup process. [Figure 4] FIG. 1 is a diagram illustrating an example of a PPDU used in the IEEE standard. [Figure 5] A diagram showing the arrangement of resource units RU used on a 20 MHz band. [Figure 6] A diagram showing the arrangement of resource units RU used on the 40 MHz band. [Figure 7] A diagram showing the arrangement of resource units RU used on the 80 MHz band. [Figure 8] The structure of the HE-SIG-B field is shown below. [Figure 9] An example is shown in which multiple user STAs are assigned to the same RU using the MU-MIMO technique. [Figure 10] This shows the operation with UL-MU. [Figure 11] 1 shows an example of a trigger frame. [Figure 12] 1 shows an example of a common information field of a trigger frame. [Figure 13]An example of subfields included in the per user information field is shown below. [Figure 14] The technical features of the UORA technique are explained. [Figure 15] An example of channels used / supported / defined within the 2.4 GHz band is shown below. [Figure 16] 1 illustrates an example of channels used / supported / defined within the 5 GHz band. [Figure 17] 1 illustrates an example of channels used / supported / defined within the 6 GHz band. [Figure 18] 1 shows an example of a PPDU used in this specification. [Figure 19] 1 illustrates a modified example of the transmitting device and / or receiving device of the present specification. [Figure 20] An example of HE-PPDU is shown below. [Figure 21] 1 shows an example of channel bonding. [Figure 22] An example of the structure of a non-AP MLD is shown below. [Figure 23] An example in which AP MLD and non-AP MLD are connected through a link setup process will be shown. [Figure 24] Here is an example where a Link is changed or reconnected. [Figure 25] Here are some specific examples of how Links are changed or reconnected. [Figure 26] 1 shows the operation of AP MLD and non-AP MLD for link change or reconnection. [Figure 27] 1 shows the operation of AP MLD and non-AP MLD for link change or reconnection. [Figure 28] 1 shows the operation of AP MLD and non-AP MLD for link change or reconnection. [Figure 29] 1 shows the operation of AP MLD and non-AP MLD for link change or reconnection. [Figure 30]1 shows the operation of non-AP MLD to request information about other APs. [Figure 31] A specific example of STA ratio per Link is shown below. [Figure 32] 1 shows the operation of AP MLD and non-AP MLD for link change or reconnection. [Figure 33] 1 shows the operation of AP MLD and non-AP MLD for link change or reconnection. [Figure 34] 1 shows the operation of AP MLD and non-AP MLD for link change or reconnection. [Figure 35] An example of an MLD structure that supports anchored links is shown below. [Figure 36] Anchored linkExamples of situations where changing or relinking is necessary: [Figure 37] 1 shows the operation of AP MLD and non-AP MLD for anchored link change or reconnection. [Figure 38] A specific example of an element for reconnecting an Anchored Link is shown below. [Figure 39] A specific example of an element for reconnecting an Anchored Link is shown below. [Figure 40] A specific example of the request element format is shown below. [Figure 41] A specific example of the Extended Request element format is shown below. [Figure 42] A specific example of the PV1 Probe Response Option element format is shown below. [Figure 43] 1 is a flowchart illustrating the operation of a multi-link device. [Figure 44] 10 is a flowchart illustrating the operation of an AP multilink device. DETAILED DESCRIPTION OF THE INVENTION

[0011] As used herein, "A or B" can mean "A only," "B only," or "both A and B." In other words, 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 "A only," "B only," "C only," or "any combination of A, B, and C."

[0012] 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 "A only," "B only," or "both A and B." For example, "A, B, C" can mean "A, B, or C."

[0013] As used herein, "at least one of A and B" can mean "A only," "B only," or "both A and B." Furthermore, as used herein, the expressions "at least one of A or B" and "at least one of A and / or B" can be interpreted in the same way as "at least one of A and B."

[0014] Furthermore, in this specification, "at least one of A, B, and C" can mean "A only," "B only," "C only," or "any combination of A, B, and C." Furthermore, "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."

[0015] Furthermore, parentheses used in this specification may mean "for example." Specifically, when "control information (EHT-Signal)" is used, it may mean that "EHT-Signal" has been proposed as an example of "control information." In other words, "control information" in this specification is not limited to "EHT-Signal," and it may mean that "EHT-Signal" has been proposed as an example of "control information." Furthermore, when "control information (i.e., EHT-signal)" is used, it may mean that "EHT-signal" has been proposed as an example of "control information."

[0016] Technical features individually described in one drawing in this specification can be realized individually or simultaneously.

[0017] The following example of the present specification may be applied to various wireless communication systems. For example, the following example of the present specification may be applied to a wireless local area network (WLAN) system. For example, the present specification may be applied to the IEEE 802.11a / g / n / ac standard or the IEEE 802.11ax standard. The present specification may also be applied to the newly proposed EHT standard or the IEEE 802.11be standard. The present specification may also be applied to a new wireless RAN standard that is an enhancement of the EHT standard or the IEEE 802.11be. The present specification may also be applied to a mobile communication system. For example, the present specification may be applied to a mobile communication system based on LTE (Long Term Evolution) and its evolution based on the 3GPP (3rd Generation Partnership Project) standard. The present specification may also be applied to a 5G NR standard communication system based on the 3GPP standard.

[0018] In order to explain the technical features of the present specification, the technical features to which the present specification can be applied will be explained below.

[0019] FIG. 1 shows an example of a transmitting device and / or a receiving device of this specification.

[0020] The example of FIG. 1 can implement various technical features described below. FIG. 1 relates to at least one STA (station). For example, the STA (110, 120) herein 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) herein 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) herein 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.

[0021] For example, the STAs (110, 120) can act as either an access point (AP) or a non-AP. 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 may also be referred to as an AP STA.

[0022] The STAs (110, 120) of the present specification may support various communication standards other than the IEEE 802.11 standard. For example, they may support communication standards according to the 3GPP standard (e.g., LTE, LTE-A, 5G NR standard). The STAs of the present specification may be implemented in various devices such as mobile phones, vehicles, and personal computers. The STAs of the present specification may support communication for various communication services such as voice calls, video calls, data communications, and self-driving and autonomous driving.

[0023] As used herein, the STAs (110, 120) may include a medium access control (MAC) and physical layer interface to the wireless medium in accordance with the IEEE 802.11 standard.

[0024] The STAs (110, 120) will be described below based on sub-figure (a) of FIG.

[0025] The first STA (110) may include a processor 111, a memory 112, and a transceiver 113. The illustrated processor, memory, and transceiver may each be implemented on a separate chip, or at least two or more of the above blocks / functions may be implemented on a single chip.

[0026] The transceiver 113 of the first STA transmits and receives signals, specifically, IEEE 802.11 packets (for example, IEEE 802.11a / b / g / n / ac / ax / be, etc.).

[0027] 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 to be transmitted via the transceiver (i.e., transmitted signals).

[0028] For example, the second STA (120) can perform the intended operations 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.).

[0029] 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 perform 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 to be transmitted via the transceiver (i.e., transmitted signals).

[0030] For example, in the following specification, the operation of the device represented by AP can be performed by the first STA (110) or the second STA (120). For example, if the first STA (110) is an AP, the operation of the device represented by AP can be controlled by the processor 111 of the first STA (110), and related signals can be transmitted or received via the transceiver 113 controlled by the processor 111 of the first STA (110). Also, control information related to the operation of the AP and the transmitted / received signals of the AP can be stored in the memory 112 of the first STA (110). Also, if the second STA (110) is an AP, the operation of the device represented by AP can be controlled by the processor 121 of the second STA (120), and related signals can be transmitted or received via the transceiver 123 controlled by the processor 121 of the second STA (120). Additionally, control information related to the operation of the AP and the AP's transmission / reception signals can be stored in the memory 122 of the second STA (110).

[0031] For example, in the following specification, the operation of a device indicated as non-AP (or User-STA) can be performed by 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 can be controlled by the processor 121 of the second STA (120), and related signals can be 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 AP transmission / reception signals can be stored in the memory 122 of the second STA (120). For example, if the first STA (110) is a non-AP, the operation of the device indicated as non-AP can be controlled by the processor 111 of the first STA (110), and related signals can be 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 the AP's transmission / reception signals can be stored in the memory 112 of the first STA (110).

[0032] In the following description, devices referred to as a (transmitting / receiving) STA, a first STA, a second STA, STA1, STA2, an AP, a first AP, a second AP, AP1, AP2, a (transmitting / receiving) terminal, a (transmitting / receiving) device, a (transmitting / receiving) apparatus, a network, etc. may refer to the STAs (110, 120) in Figure 1. For example, devices referred to as a (transmitting / receiving) STA, a first STA, a second STA, STA1, STA2, an AP, a first AP, a second AP, AP1, AP2, a (transmitting / receiving) terminal, a (transmitting / receiving) device, a (transmitting / receiving) apparatus, a network, etc. without specific reference numerals may also refer to the STAs (110, 120) in Figure 1. For example, in the following example, the operations of various STAs transmitting and receiving signals (e.g., PPPDUs) may be performed by transceivers 113, 123 in Figure 1. In the following example, various STAs may generate transmission / reception signals or perform data processing or calculations in advance for transmission / reception signals by using processors 111 and 121 in FIG. 1. For example, examples of operations for generating transmission / reception signals or performing data processing or calculations in advance for transmission / reception signals may include: 1) operations for determining / obtaining / configuring / calculating / decoding / encoding bit information for subfields (SIG, STF, LTF, Data) included in a PPDU; 2) operations for determining / configuring / obtaining time resources and frequency resources (e.g., subcarrier resources) used for the subfields (SIG, STF, LTF, Data) included in a PPDU; 3) operations for determining / configuring / obtaining specific sequences (e.g., pilot sequences, STF / LTF sequences, extra sequences applied to SIG) used for the subfields (SIG, STF, LTF, Data) included in a PPDU; 4) operations for power control and / or power saving applied to the STAs; and 5) operations for 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 can be stored in memories 112, 122 of FIG. 1.

[0033] The device / STA of the above-mentioned sub-figure (a) of Fig. 1 can be modified as shown in sub-figure (b) of Fig. 1. Hereinafter, the STA (110, 120) of this specification will be described based on sub-figure (b) of Fig. 1.

[0034] For example, the transceivers 113 and 123 shown in sub-drawing (b) of Figure 1 can perform the same functions as the transceivers shown in sub-drawing (a) of Figure 1 described above. For example, the processing chips 114 and 124 shown in sub-drawing (b) of Figure 1 can include processors 111 and 121 and memories 112 and 122. The processors 111 and 121 and memories 112 and 122 shown in sub-drawing (b) of Figure 1 can perform the same functions as the processors 111 and 121 and memories 112 and 122 shown in sub-drawing (a) of Figure 1 described above.

[0035] 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 apparatus, and / or a transmitting apparatus may refer to the STAs (110, 120) shown in sub-drawing (a) / (b) of Fig. 1 or the processing chips 114, 124 shown in sub-drawing (b) of Fig. 1. That is, the technical features of this specification may be performed by the STAs (110, 120) shown in sub-drawing (a) / (b) of Fig. 1, or may be performed only by the processing chips 114, 124 shown in sub-drawing (b) of Fig. 1. For example, the technical feature of a transmitting STA transmitting a control signal can be understood as a technical feature of a control signal generated by processors 111 and 121 shown in sub-drawings (a) and (b) of Fig. 1 being transmitted via transceivers 113 and 123 shown in sub-drawings (a) and (b) of Fig. 1. Alternatively, the technical feature of a transmitting STA transmitting a control signal can be understood as a technical feature of a control signal transmitted to transceivers 113 and 123 being generated by processing chips 114 and 124 shown in sub-drawing (b) of Fig. 1.

[0036] For example, the technical feature of the receiving STA receiving a control signal can be understood as the technical feature of the control signal being received by the transceivers 113 and 123 shown in sub-drawing (a) of Fig. 1. Alternatively, the technical feature of the receiving STA receiving a control signal can be understood as the technical feature of the control signal received by the transceivers 113 and 123 shown in sub-drawing (a) of Fig. 1 being acquired by the processors 111 and 121 shown in sub-drawing (a) of Fig. 1. Alternatively, the technical feature of the receiving STA receiving a control signal can be understood as the technical feature of the control signal received by the transceivers 113 and 123 shown in sub-drawing (b) of Fig. 1 being acquired by the processing chips 114 and 124 shown in sub-drawing (b) of Fig. 1.

[0037] 1, software code 115, 125 may be provided within memory 112, 122. Software code 115, 125 may include instructions that control the operation of processor 111, 121. Software code 115, 125 may be included in a variety of programming languages.

[0038] 1 may include an application-specific integrated circuit (ASIC), other chipsets, logic circuits, and / or data processing devices. The processor may be an application processor (AP). For example, the processor 111, 121 or the processing chip 114, 124 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 be a SNAPDRAGON™ series processor manufactured by Qualcomm®, an EXYNOS™ series processor manufactured by Samsung®, an A series processor manufactured by Apple®, a HELIO™ series processor manufactured by MediaTek®, an ATOM™ series processor manufactured by INTEL®, or an enhanced processor thereof.

[0039] In this specification, an uplink may refer to a link for communication from a non-AP STA to an AP STA, and uplink PPDUs / packets / signals, etc. may be transmitted via the uplink. Also, in this specification, a downlink may refer to a link for communication from an AP STA to a non-AP STA, and downlink PPDUs / packets / signals, etc. may be transmitted via the downlink.

[0040] FIG. 2 is a conceptual diagram showing the structure of a wireless RAN (WLAN).

[0041] The top of Figure 2 shows the structure of an IEEE (Institute of Electrical and Electronic Engineers) 802.11 infrastructure basic service set (BSS).

[0042] Referring to the top of Figure 2, a wireless RAN system may include one or more infrastructure BSSs (200, 205) (hereinafter referred to as BSSs). A BSS (200, 205) is a collection of APs and STAs, such as an access point (AP) 225 and a station (STA1) 200-1, that can successfully synchronize and communicate with each other, and is not a concept that refers to a specific area. A BSS (205) may also include one AP (230) and one or more STAs (205-1, 205-2) that can join the BSS.

[0043] The BSS may include at least one STA, APs (225, 230) that provide a distribution service, and a distribution system (DS, 210) that connects multiple APs.

[0044] The distributed system 210 can realize an extended service set (ESS, 240) by connecting several BSSs (200, 205). The ESS (240) can be used as a term to indicate a network formed by connecting one or more APs via the distributed system 210. The APs included in one ESS (240) can have the same service set identification (SSID).

[0045] The portal (220) can act as a bridge between the wireless RAN network (IEEE 802.11) and other networks (e.g., 802.X).

[0046] In the BSS shown at the top of Figure 2, a network between APs (225, 230) and a network between APs (225, 230) and STAs (200-1, 205-1, 205-2) can be realized. However, it may also be possible to establish a network between STAs without APs (225, 230) and communicate with each other. A network that establishes 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).

[0047] The bottom of Figure 2 is a conceptual diagram showing the IBSS.

[0048] Referring to the bottom of Figure 2, an IBSS is a BSS that operates in ad-hoc mode. Since an IBSS does not include an AP, there is no centralized management entity. 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) may be mobile STAs, and connection to a distributed system is not permitted, forming a self-contained network.

[0049] FIG. 3 is a diagram illustrating a general link setup process.

[0050] In step S310 shown in the figure, the STA may perform a network discovery operation. The network discovery operation may include a scanning operation by the STA. That is, in order for the STA to access a network, it must search for a joinable network. Before joining a wireless network, the STA must identify a compatible network. The process of identifying networks present in a specific area is called scanning. Scanning methods include active scanning and passive scanning.

[0051] FIG. 3 illustrates an exemplary network discovery operation including an active scanning process. A STA performing active scanning transmits a probe request frame to search for nearby APs while changing channels and waits for a response. A responder transmits a probe response frame to the STA that transmitted the probe request frame in response to the probe request frame. Here, the responder may be the STA that last transmitted a beacon frame in the BSS of the channel being scanned. In a BSS, the AP transmits the beacon frame, so the AP is the responder. In an IBSS, the STAs in the IBSS transmit the beacon frame in sequence, so the responder is not fixed. 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., transmit and receive probe request / response on channel 2).

[0052] Although not shown in the example of FIG. 3, the scanning operation may also be performed in a passive scanning manner. A STA performing scanning based on passive scanning can wait for a signal frame while changing channels. A signal frame is one of the management frames in IEEE 802.11, and is transmitted periodically to announce the existence of a wireless network and allow a scanning STA to search for and join the wireless network. In a BSS, an AP periodically transmits signal frames, while in an IBSS, STAs within the IBSS transmit signal frames in turn. When a scanning STA receives a signal frame, it stores information about the BSS included in the signal frame and records the signal frame information on each channel as it moves to another channel. A STA receiving a signal frame stores the BSS-related information included in the received signal frame, moves to the next channel, and performs scanning on the next channel in the same manner.

[0053] An STA that has discovered a network can perform an authentication process through step S320. This authentication process can be referred to as a first authentication process to clearly distinguish it from the security setup operation in step S340, which will be described later. The authentication process in S320 can 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 for the authentication request / response corresponds to a management frame.

[0054] The authentication frame may include information such as an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a Robust Security Network (RSN), a Finite Cyclic Group, etc.

[0055] 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.

[0056] A successfully authenticated STA can perform an association process according to 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 various capability-related information, such as a signal 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 interworking service capabilities. For example, the association 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.

[0057] Thereafter, in step S340, the STA may perform a security setup process, which may include, for example, a private key setup process via a four-way handshaking using an Extensible Authentication Protocol over LAN (EAPOL) frame.

[0058] FIG. 4 is a diagram showing an example of a PPDU used in the IEEE standard.

[0059] As shown in the figure, various types of PPDUs (PHY protocol data units) are used in standards such as IEEE a / g / n / ac. Specifically, the LTF and STF fields contain training signals, SIG-A and SIG-B contain control information for receiving stations, and the data field contains user data corresponding to the PSDU (MAC PDU / Aggregated MAC PDU).

[0060] 4 also includes an example of an HE PPDU of the IEEE 802.11ax standard. The HE PPDU of FIG. 4 is an example of a PPDU for multiple users, and the HE-SIG-B is included only for multiple users, and the HE-SIG-B can be omitted in a PPDU for a single user.

[0061] As shown in the figure, 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 may be transmitted during the time interval shown (e.g., 4 or 8 μs, etc.).

[0062] The resource unit (RU) used in the PPDU will be described below. The resource unit can include multiple subcarriers (or tones). The resource unit can be used when transmitting signals to multiple STAs based on the OFDMA technique. The resource unit can also be defined when transmitting a signal to one STA. The resource unit can be used for the STF, LTF, data field, etc.

[0063] FIG. 5 is a diagram showing the allocation of resource units RU used on a 20 MHz band.

[0064] As shown in Figure 5, resource units (RUs) corresponding to different numbers of tones (i.e., subcarriers) may be used to configure some fields of the HE-PPDU. For example, resources may be allocated in units of the RUs shown in the figure to the HE-STF, HE-LTF, and data fields.

[0065] As shown at the top of Figure 5, 26 units (i.e., units corresponding to 26 tones) can be allocated. Six tones can be used as a guard band in the leftmost band of the 20 MHz band, and five tones can be used as a guard band in the rightmost band of the 20 MHz band. Seven DC tones can be inserted into the center band, i.e., the DC band, and 26 units corresponding to 13 tones can be allocated to each side of the DC band. Other bands can be allocated 26 units, 52 units, or 106 units. Each unit can be allocated for a receiving station, i.e., a user.

[0066] On the other hand, the RU arrangement of Figure 5 can be utilized not only in a situation for multiple users MU but also in a situation for a single user SU, in which case, as shown at the bottom of Figure 5, one 242-unit can be used, and in this case, three DC tones can be inserted.

[0067] In the example of Figure 5, various sizes of RUs are proposed, i.e., 26-RU, 52-RU, 106-RU, 242-RU, etc., but the specific sizes of such RUs can be expanded or increased, so this embodiment is not limited to the specific size of each RU (i.e., the number of corresponding tones).

[0068] FIG. 6 is a diagram showing the allocation of resource units RU used on the 40 MHz band.

[0069] Just as various sizes of RUs are used in the example of Figure 5, 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, etc. may be used in the example of Figure 6. In addition, five DC tones may be inserted at the center frequency, 12 tones may be used as a guard band in the leftmost band of the 40 MHz band, and 11 tones may be used as a guard band in the rightmost band of the 40 MHz band.

[0070] Also, as shown in the figure, when used for a single user, 484 RUs may be used, but the specific number of RUs may be changed, as in the example of FIG.

[0071] FIG. 7 is a diagram showing the allocation of resource units RU used on the 80 MHz band.

[0072] Similar to the examples of Figures 5 and 6 in which various sizes of RUs are used, the example of Figure 7 may also use 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, 996-RU, etc. In addition, seven DC tones may be inserted into the center frequency, 12 tones may be used as a guard band in the leftmost band of the 80 MHz band, and 11 tones may be used as a guard band in the rightmost band of the 80 MHz band. In addition, 26-RUs using 13 tones each on the left and right of the DC band may be used.

[0073] Also, as shown, when used for a single user, 996-RU can be used, in which case five DC tones can be inserted.

[0074] The RUs described herein can be 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 via the Trigger frame. Then, 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 interval.

[0075] 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 a first STA and a second RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to a 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 within one MU PPDU.

[0076] Information regarding the location of the RU can be signaled via HE-SIG-B.

[0077] Figure 8 shows the structure of the HE-SIG-B field.

[0078] As shown, the HE-SIG-B field 810 includes a common field 820 and a user-specific field 830. The common field 820 may include information that applies commonly to all users (i.e., user STAs) that receive the SIG-B. The user-specific field 830 may be referred to as a user-specific control field. When the SIG-B is transmitted to multiple users, the user-specific field 830 may apply to only some of the multiple users.

[0079] As shown in FIG. 8, the common field 820 and the user-specific field 830 can be encoded separately.

[0080] The common field 820 can include N*8 bits of RU allocation information. For example, the RU allocation information can include information about the location of the RU. For example, as shown in FIG. 5, when a 20 MHz channel is used, the RU allocation information can include information about which RU (26-RU / 52-RU / 106-RU) is allocated to which frequency band.

[0081] An example of RU allocation information consisting of 8 bits is as follows:

[0082] [Table 1]

[0083] As shown in the example of Figure 5, a 20 MHz channel can be allocated up to nine 26-RUs. As shown in Table 1, when the RU allocation information in the common field 820 is set to "00000000," nine 26-RUs can be allocated to the corresponding channel (i.e., 20 MHz). Also, as shown in Table 1, when the RU allocation information in the common field 820 is set to "00000001," seven 26-RUs and one 52-RU can be allocated to the corresponding channel. That is, in the example of Figure 5, a 52-RU can be allocated to the rightmost side, and seven 26-RUs can be allocated to the left of that.

[0084] The example in Table 1 shows only a portion of the RU locations that can be displayed in RU allocation information.

[0085] For example, the RU allocation information may include an example of Table 2 below.

[0086] [Table 2]

[0087] "01000y2y1y0" relates to an example in which a 106-RU is allocated to the leftmost position of a 20 MHz channel, and five 26-RUs are allocated to the right of it. In this case, multiple STAs (e.g., User-STAs) can be allocated to the 106-RU based on the MU-MIMO technique. Specifically, up to eight STAs (e.g., User-STAs) can be allocated to the 106-RU, and the number of STAs (e.g., User-STAs) allocated to the 106-RU is determined based on the 3-bit information (y2y1y0). For example, if the 3-bit information (y2y1y0) is set to N, the number of STAs (e.g., User-STAs) allocated to the 106-RU based on the MU-MIMO technique can be N+1.

[0088] Generally, multiple STAs (e.g., User STAs) may be assigned to multiple RUs. However, for an RU with a certain size (e.g., 106 subcarriers) or more, multiple STAs (e.g., User STAs) may be assigned based on the MU-MIMO technique.

[0089] As shown in FIG. 8, the user-specific field 830 may include multiple user fields. As described above, the number of STAs (e.g., user STAs) allocated to a specific channel may be determined based on the RU allocation information in the common field 820. For example, if the RU allocation information in the common field 820 is '00000000', one user STA may be allocated to each of the nine 26-RUs (i.e., a total of nine user STAs may be allocated). That is, up to nine user STAs may be allocated to a specific channel using the OFDMA technique. In other words, up to nine user STAs may be allocated to a specific channel using the non-MU-MIMO technique.

[0090] For example, if RU allocation is set to "01000y2y1y0," multiple user STAs can be allocated to the leftmost 106-RU using the MU-MIMO technique, and five user STAs can be allocated to the five 26-RUs to the right using the non-MU-MIMO technique. This case is embodied in the example of FIG. 9.

[0091] FIG. 9 shows an example in which multiple user STAs are assigned to the same RU using the MU-MIMO technique.

[0092] For example, if RU allocation is set to "01000010" as shown in Figure 9, a 106-RU may be allocated to the leftmost side of a specific channel, and five 26-RUs may be allocated to the right of that, based on Table 2. Also, a total of three user STAs may be allocated to the 106-RU using the MU-MIMO technique. As a result, a total of eight user STAs are allocated, and therefore the user-specific field 830 of the HE-SIG-B may include eight user fields.

[0093] The eight user fields may be included in the order shown in Figure 9. Also, as shown in Figure 8, two user fields may be implemented in one user block field.

[0094] The user fields shown in Figures 8 and 9 can be configured based on two formats. That is, the user field related to the MU-MIMO technique can be configured in a first format, and the user field related to the non-MU-MIMO technique can be configured in a second format. Referring to the example of Figure 9, user fields 1 to 3 can be based on the first format, and user fields 4 to 8 can be based on the second format. The first format or the second format can contain bit information of the same length (e.g., 21 bits).

[0095] Each User field may have the same size (for example, 21 bits). For example, the User field of the first format (the format of the MU-MIMO technique) may be configured as follows:

[0096] For example, the first bits (e.g., B0-B10) in the User field (i.e., 21 bits) may include identification information (e.g., STA-ID, partial AID, etc.) of the User STA to which the User field is assigned. Also, the second bits (e.g., B11-B14) in the User field (i.e., 21 bits) may include information regarding spatial configuration. Specifically, examples of the second bits (i.e., B11-B14) may be as shown in Tables 3 and 4 below.

[0097] [Table 3]

[0098] [Table 4]

[0099] As shown in Table 3 and / or Table 4, the second bits (i.e., B11-B14) may include information regarding the number of spatial streams allocated to multiple user STAs allocated according to the MU-MIMO technique. For example, as shown in FIG. 9, when three user STAs are allocated to 106-RU according to the MU-MIMO technique, N_user is set to '3', and the values ​​of N_STS[1], N_STS[2], and N_STS[3] may be determined as shown in Table 3. For example, when the value of the second bits (B11-B14) is '0011', N_STS[1]=4, N_STS[2]=1, and N_STS[3]=1 may be set. That is, in the example of FIG. 9, four spatial streams may be allocated to user field 1, one spatial stream may be allocated to user field 2, and one spatial stream may be allocated to user field 3.

[0100] As shown in the examples of Table 3 and / or Table 4, information on the number of spatial streams for a user station (User STA) (i.e., second bits, B11-B14) may be configured with 4 bits. Also, the information on the number of spatial streams for a user station (User STA) (i.e., second bits, B11-B14) may support up to 8 spatial streams. Also, the information on the number of spatial streams (i.e., second bits, B11-B14) may support up to 4 spatial streams for one user STA.

[0101] Additionally, the third bit (i.e., B15-18) in the User field (i.e., 21 bits) can contain MCS (Modulation and coding scheme) information, which can be applied to the data field in the PPDU containing the SIG-B.

[0102] As used herein, MCS, MCS information, MCS index, MCS field, etc. may be represented by a specific index value. For example, MCS information may be represented by index 0 to index 11. The MCS information may include information about a modulation type (e.g., BPSK, QPSK, 16-QAM, 64-QAM, 256-QAM, 1024-QAM, etc.) and information about a coding rate (e.g., 1 / 2, 2 / 3, 3 / 4, 5 / 6, etc.). The MCS information may exclude information about a channel coding type (e.g., BCC or LDPC).

[0103] Also, the fourth bit (ie, B19) in the User field (ie, 21 bits) can be a Reserved field.

[0104] In addition, the fifth bit (i.e., B20) in the User field (i.e., 21 bits) may include information about the coding type (e.g., BCC or LDPC). That is, the fifth bit (i.e., B20) may include information about the type of channel coding (e.g., BCC or LDPC) applied to the data field in the PPDU containing the SIG-B.

[0105] The above example relates to the User field of the first format (format for the MU-MIMO technique). An example of the User field of the second format (format for the non-MU-MIMO technique) is as follows:

[0106] The first bit (e.g., B0-B10) in the User field of the second format may include identification information of the User STA. The second bit (e.g., B11-B13) in the User field of the second format may include information regarding the number of spatial streams applied to the RU. The third bit (e.g., B14) in the User field of the second format may include information regarding whether a beamforming steering matrix is ​​applied. The fourth bit (e.g., B15-B18) in the User field of the second format may include modulation and coding scheme (MCS) information. The fifth bit (e.g., B19) in the User field of the second format may include information regarding whether dual carrier modulation (DCM) is applied. The sixth bit (i.e., B20) in the User field of the second format may include information regarding the coding type (e.g., BCC or LDPC).

[0107] 10 shows the operation of 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). When the PPDU including the trigger frame is received, a TB (trigger-based) PPDU is transmitted after a delay of SIFS.

[0108] The TB PPDUs (1041, 1042) are transmitted during the same time period and can be transmitted from multiple STAs (e.g., User STAs) whose AIDs are indicated in the Trigger Frame (1030). The ACK frame 1050 for the TB PPDU can be realized in various forms.

[0109] Specific features of the trigger frame will be described with reference to Figures 11 to 13. When UL-MU communication is used, the orthogonal frequency division multiple access (OFDMA) technique or the MU MIMO technique can be used, or the OFDMA and MU MIMO techniques can be used simultaneously.

[0110] 11 shows an example of a trigger frame. The trigger frame in FIG. 11 allocates resources for uplink multiple-user (MU) transmission and can be transmitted, for example, from an AP. The trigger frame can be configured as a MAC frame and can be included in a PPDU.

[0111] Some of the fields shown in Figure 11 may be omitted, other fields may be added, and the length of each field may be changed differently from that shown.

[0112] The frame control field 1110 in Figure 11 contains information about the MAC protocol version and other additional control information, and the duration field 1120 may contain information about time information for NAV setting and an STA identifier (e.g., AID).

[0113] Furthermore, the RA field 1130 includes address information of the STA receiving the trigger frame, but may be omitted as 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 upstream PPDU transmitted in response to the trigger frame and information controlling the content of the SIG-A field (i.e., the HE-SIG-A field) of the upstream PPDU transmitted in response to the trigger frame may be included. Furthermore, the common control information may include information regarding the length of the CP and the length of the LTF field of the upstream PPDU transmitted in response to the trigger frame.

[0114] It is also preferable to include per user information fields 1160#1 to 1160#N corresponding to the number of receiving STAs that receive the trigger frame of Figure 11. The per user information fields may also be called "allocation fields."

[0115] The trigger frame of FIG. 11 may also include a padding field 1170 and a frame check sequence field 1180.

[0116] Each of the per user information fields 1160#1 to 1160#N shown in FIG. 11 may further include multiple subfields.

[0117] 12 shows an example of a common information field of a trigger frame. Some of the subfields in FIG. 12 may be omitted, and other subfields may be added. Also, the length of each of the illustrated subfields may be modified.

[0118] The illustrated length field 1210 has the same value as the length field of the L-SIG field of the upstream PPDU transmitted corresponding to the trigger frame, and the length field of the L-SIG field of the upstream PPDU indicates the length of the upstream PPDU. As a result, the length field 1210 of the trigger frame can be used to indicate the length of the corresponding uplink PPDU.

[0119] In addition, the cascade indicator field 1220 indicates whether a cascade operation is performed. Cascade operation means that both downlink MU transmission and uplink MU transmission are performed within the same TXOP. That is, it means that uplink MU transmission is performed after a preset time (e.g., SIFS) has elapsed since the downlink MU transmission. During cascade operation, there can be only one transmitter (e.g., AP) performing downlink communication, and multiple transmitters (e.g., non-APs) performing uplink communication.

[0120] The CS request field 1230 indicates whether the receiving device that received the trigger frame should take into account the state of the wireless medium, NAV, etc. when transmitting the corresponding uplink PPDU.

[0121] The HE-SIG-A information field 1240 may include information that controls the content of the SIG-A field (i.e., the HE-SIG-A field) of the upstream PPDU transmitted in response to the trigger frame.

[0122] The CP and LTF type field 1250 may include information about the LTF length and CP length of the upstream PPDU transmitted corresponding to the trigger frame. The trigger type field 1260 may indicate the purpose for which the trigger frame is used, such as normal triggering, triggering for beamforming, or a request for Block ACK / NACK.

[0123] 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.

[0124] 13 shows an example of subfields included in a per user information field. The user information field 1300 of FIG. 13 can be understood as any one of the individual user information fields 1160#1 to 1160#N previously mentioned in FIG. 11. Some of the subfields included in the user information field 1300 of FIG. 13 can be omitted, and other subfields can be added. Also, the length of each of the illustrated subfields can be modified.

[0125] The User Identifier field 1310 in FIG. 13 represents an identifier of the STA (i.e., receiving STA) corresponding to individual user information, and an example of the identifier can be all or part of the AID (association identifier) ​​value of the receiving STA.

[0126] Also, an RU Allocation field 1320 may be included. That is, when a receiving STA identified in the user identifier field 1310 transmits a TB PPDU corresponding to the trigger frame, the TB PPDU is transmitted via an RU indicated by the RU Allocation field 1320. In this case, the RU indicated by the RU Allocation field 1320 may be the RU shown in FIGS. 5, 6, and 7.

[0127] 13 may include a coding type field 1330. The coding type field 1330 may indicate the coding type of the TB PPDU. For example, if BCC coding is applied to the TB PPDU, the coding type field 1330 may be set to '1', and if LDPC coding is applied to the TB PPDU, the coding type field 1330 may be set to '0'.

[0128] 13 may include an MCS field 1340. The MCS field 1340 may indicate an MCS scheme applied to the TB PPDU. For example, if BCC coding is applied to the TB PPDU, the coding type field 1330 may be set to '1', and if LDPC coding is applied, the coding type field 1330 may be set to '0'.

[0129] The UL OFDMA-based Random Access (UORA) technique will be described below.

[0130] Figure 14 illustrates the technical features of the UORA technique.

[0131] A transmitting STA (e.g., AP) may allocate six RU resources via a trigger frame as shown in FIG. 14. Specifically, the AP may allocate a first RU resource (AID 0, RU 1), a second RU resource (AID 0, RU 2), a third RU resource (AID 0, RU 3), a fourth RU resource (AID 2045, RU 4), ​​a fifth RU resource (AID 2045, RU 5), and a sixth RU resource (AID 3, RU 6). Information regarding AID 0, AID 3, or AID 2045 may be included, for example, in the user identification field 1310 of FIG. 13. Information regarding RUs 1 through 6 may be included, for example, in the RU allocation field 1320 of FIG. 13. AID=0 may indicate UORA resources for an associated STA, and AID=2045 may indicate UORA resources for an unassociated STA. As a result, the first to third RU resources in Figure 14 can be used as UORA resources for associated STAs, the fourth and fifth RU resources in Figure 14 can be used as UORA resources for unassociated STAs, and the sixth RU resource in Figure 14 can be used as a resource for a normal UL MU.

[0132] In the example shown in Figure 14, the OFDMA random access BackOff (OBO) counter of STA1 is decremented to 0, and STA1 randomly selects the second RU resource, AID 0, RU 2. Also, since the OBO counters of STA2 / 3 are greater than 0, no uplink resources are allocated to STA2 / 3. Also, in Figure 14, STA4 includes its own AID (i.e., AID=3) in the trigger frame, and therefore is allocated resources in RU 6 without backoff.

[0133] Specifically, since STA1 in FIG. 14 is an associated STA, there are a total of three eligible RA RUs for STA1 (RU1, RU2, RU3), and therefore STA1 decrements its OBO counter by 3, resulting in the OBO counter becoming 0. Also, since STA2 in FIG. 14 is an associated STA, there are a total of three eligible RA RUs for STA2 (RU1, RU2, RU3), and therefore STA2 decrements its OBO counter by 3, but the OBO counter is still greater than 0. Also, since STA3 in FIG. 14 is an unassociated STA, there are a total of two eligible RA RUs for STA3 (RU4, RU5), and therefore STA3 decrements its OBO counter by 2, but the OBO counter is still greater than 0.

[0134] FIG. 15 shows an example of channels used / supported / defined within the 2.4 GHz band.

[0135] The 2.4 GHz band may be referred to by other names such as the first band, etc. The 2.4 GHz band may also refer to a frequency range in which channels with center frequencies adjacent to 2.4 GHz (e.g., channels with center frequencies between 2.4 and 2.5 GHz) are used / supported / defined.

[0136] The 2.4 GHz band may include multiple 20 MHz channels. 20 MHz within the 2.4 GHz band may have multiple channel indexes (e.g., index 1 through index 14). For example, the center frequency of a 20 MHz channel assigned channel index 1 may be 2.412 GHz, the center frequency of a 20 MHz channel assigned channel index 2 may be 2.417 GHz, and the center frequency of a 20 MHz channel assigned channel index N may be (2.407 + 0.005 * N) GHz. The channel index may be referred to by various names, such as a channel number. The specific values ​​of the channel index and center frequency may be changed.

[0137] FIG. 15 exemplarily illustrates four channels in the 2.4 GHz band. The illustrated first to fourth frequency regions 1510 to 1540 each include one channel. For example, the first frequency region 1510 may include channel 1 (a 20 MHz channel having an index of 1). The center frequency of channel 1 may be set to 2412 MHz. The second frequency region 1520 may include channel 6. The center frequency of channel 6 may be set to 2437 MHz. The third frequency region 1530 may include channel 11. The center frequency of channel 11 may be set to 2462 MHz. The fourth frequency region 1540 may include channel 14. The center frequency of channel 14 may be set to 2484 MHz.

[0138] FIG. 16 illustrates an example of channels used / supported / defined within the 5 GHz band.

[0139] The 5 GHz band may be referred to by other names such as a second band or band. The 5 GHz band may refer to a frequency range in which channels with center frequencies equal to or greater than 5 GHz and less than 6 GHz (or less than 5.9 GHz) are used / supported / defined. Alternatively, the 5 GHz band may include multiple channels between 4.5 GHz and 5.5 GHz. The specific values ​​shown in FIG. 16 may be changed.

[0140] The channels within the 5 GHz band include the Unlicensed National Information Infrastructure (UNII)-1, UNII-2, UNII-3, and ISM. UNII-1 can be referred to as UNII Low. UNII-2 can include frequency regions called UNII Mid and UNII-2 Extended. UNII-3 can be referred to as UNII Upper.

[0141] Multiple channels can be configured within the 5 GHz band, and the bandwidth of each channel can be variously configured, such as 20 MHz, 40 MHz, 80 MHz, or 160 MHz. For example, the 5170 MHz to 5330 MHz frequency region / range within UNII-1 and UNII-2 can be divided into eight 20 MHz channels. The 5170 MHz to 5330 MHz frequency region / range can be divided into four channels via a 40 MHz frequency region. The 5170 MHz to 5330 MHz frequency region / range can be divided into two channels via an 80 MHz frequency region. Alternatively, the 5170 MHz to 5330 MHz frequency region / range can be divided into one channel via a 160 MHz frequency region.

[0142] FIG. 17 illustrates an example of channels used / supported / defined within the 6 GHz band.

[0143] The 6 GHz band may be referred to by other names such as the third band / band. The 6 GHz band may refer to a frequency range in which channels with center frequencies of 5.9 GHz or higher are used / supported / defined. The specific values ​​shown in FIG. 17 may be changed.

[0144] For example, the 20 MHz channels in Figure 17 can be defined starting from 5.940 GHz. Specifically, the leftmost channel of the 20 MHz channels in Figure 17 can have an index (or channel index, channel number, etc.) of 1, and can be assigned a center frequency of 5.945 GHz. That is, the center frequency of channel index N can be determined as (5.940 + 0.005 * N) GHz.

[0145] Thus, the indices (or channel numbers) of the 20 MHz channels in FIG. 17 can be 1, 5, 9, 13, 17, 21, 25, 29, 33, 37, 41, 45, 49, 53, 57, 61, 65, 69, 73, 77, 81, 85, 89, 93, 97, 101, 105, 109, 113, 117, 121, 125, 129, 133, 137, 141, 145, 149, 153, 157, 161, 165, 169, 173, 177, 181, 185, 189, 193, 197, 201, 205, 209, 213, 217, 221, 225, 229, 233. Also, following the (5.940+0.005*N) GHz rule mentioned above, the indices for the 40 MHz channels in Figure 17 can be 3, 11, 19, 27, 35, 43, 51, 59, 67, 75, 83, 91, 99, 107, 115, 123, 131, 139, 147, 155, 163, 171, 179, 187, 195, 203, 211, 219, 227.

[0146] In the example of FIG. 17, 20, 40, 80, and 160 MHz channels are shown, but 240 MHz and 320 MHz channels can also be added.

[0147] The PPDUs transmitted / received by the STAs in this specification are described below.

[0148] FIG. 18 shows an example of a PPDU used in this specification.

[0149] 18 may be referred to by various names such as an EHT PPDU, a transmit PPDU, a receive PPDU, a first type, or an Nth type PPDU. For example, in this specification, a PPDU or an EHT PPDU may be referred to by various names such as a transmit PPDU, a receive PPDU, a first type, or an Nth type PPDU. Furthermore, an EHT PPDU may be used in an EHT system and / or a new wireless RAN system that is an improvement over an EHT system.

[0150] The PPDU of Figure 18 may indicate some or all of the PPDU types used in the EHT system. For example, the example of Figure 18 can be used for both single-user (SU) mode and multi-user (MU) mode. In other words, the PPDU of Figure 18 is a PPDU for one receiving STA or multiple receiving STAs. When the PPDU of Figure 18 is used for trigger-based (TB) mode, the EHT-SIG of Figure 18 may be omitted. In other words, a STA that receives a trigger frame for uplink-MU (UL-MU) communication can transmit a PPDU in the example of Figure 18 from which the EHT-SIG is omitted.

[0151] In FIG. 18, the L-STF to EHT-LTF can be referred to as a preamble or a physical preamble, and can be generated / transmitted / received / acquired / decoded in the physical layer.

[0152] The subcarrier spacing of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-SIG fields in Figure 18 may be determined to be 312.5 kHz, and the subcarrier spacing of the EHT-STF, EHT-LTF, and Data fields may be determined to be 78.125 kHz. That is, the tone index (or subcarrier index) of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-SIG fields may be expressed in units of 312.5 kHz, and the tone index (or subcarrier index) of the EHT-STF, EHT-LTF, and Data fields may be expressed in units of 78.125 kHz.

[0153] The L-LTF and L-STF in the PPDU of FIG. 18 above can be the same as conventional fields.

[0154] The L-SIG field in FIG. 18 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 6 Tail bits. 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 may be determined based on the type of PPDU. For example, if the PPDU is a non-HT, HT, or VHT PPDU, or an EHT PPDU, the value of the Length field may be determined to be a multiple of 3. For example, if the PPDU is an HE PPDU, the value of the Length field may be determined to be "multiple of 3 + 1" or "multiple of 3 + 2." In other words, for a non-HT, HT, VHT PPDU, or EHT PPDU, the value of the Length field can be determined to be a multiple of 3, and for an HE PPDU, the value of the Length field can be determined to be "a multiple of 3 + 1" or "a multiple of 3 + 2".

[0155] For example, the transmitting STA may apply BCC encoding based on a code rate of 1 / 2 to the 24-bit information in the L-SIG field. The transmitting STA may then obtain 48 BCC-encoded bits. BPSK modulation may be applied to the 48 encoded bits to generate 48 BPSK symbols. The transmitting STA may map the 48 BPSK symbols to positions excluding the pilot subcarriers {subcarrier indexes -21, -7, +7, +21} and the DC subcarrier {subcarrier index 0}. Consequently, the 48 BPSK symbols may be mapped to subcarrier indexes -26 to -22, -20 to -8, -6 to -1, +1 to +6, +8 to +20, and +22 to +26. The transmitting STA may further map signals of {-1, -1, -1, 1} to subcarrier indexes {-28, -27, +27, +28}. The above signal can be used for channel estimation for the frequency domain corresponding to {-28, -27, +27, +28}.

[0156] The transmitting STA can generate an RL-SIG, which is generated similarly to the L-SIG. BPSK modulation can be applied to the RL-SIG. The receiving STA can determine whether the received PPDU is an HE PPDU or an EHT PPDU based on the presence of the RL-SIG.

[0157] A Universal SIG (U-SIG) can be inserted after the RL-SIG in Figure 18. The U-SIG can be called various names such as a first SIG field, a first SIG, a first type SIG, a control signal, a control signal field, or a first (type) control signal.

[0158] The U-SIG may contain N bits of information, including information for identifying the type of EHT PPDU. For example, the U-SIG may be configured based on two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG may have a duration of 4 us. Each symbol of the U-SIG may be used to transmit 26 bits of information. For example, each symbol of the U-SIG may be transmitted and received based on 52 data tones and 4 pilot tones.

[0159] For example, A-bit information (e.g., 52 uncoded bits) can be transmitted via the U-SIG (or U-SIG field), with the first symbol of the U-SIG transmitting the first X-bit information (e.g., 26 uncoded bits) of the total A-bit information, and the second symbol of the U-SIG transmitting the remaining Y-bit information (e.g., 26 uncoded bits) of the total A-bit information. For example, the transmitting STA can obtain the 26 uncoded bits included in each U-SIG symbol. The transmitting STA can perform convolutional encoding (i.e., BCC encoding) based on a rate of R=½ 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 can be transmitted based on 56 tones (subcarriers) from subcarrier index -28 to subcarrier index +28, excluding DC index 0. The 52 BPSK symbols generated by the transmitting STA can be transmitted based on the remaining tones (subcarriers) excluding the pilot tones -21, -7, +7, and +21.

[0160] 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 tail field may be transmitted via the second symbol of the U-SIG. The CRC field may be generated based on the 26 bits assigned to the first symbol of the U-SIG and the remaining 16 bits in the second symbol excluding the CRC / tail field, and may be generated based on a conventional CRC calculation algorithm. In addition, the tail field may be used to terminate the trellis of a convolutional decoder and may be set to, for example, "000000."

[0161] The A-bit information (e.g., 52 uncoded bits) transmitted by the U-SIG (or U-SIG field) can be divided into version-independent bits and version-dependent bits. For example, the size of the version-independent bits can be fixed or variable. For example, the version-independent bits can be assigned only to the first symbol of the U-SIG, or the version-independent bits can be assigned to both the first and second symbols of the U-SIG. For example, the version-independent bits and the version-dependent bits can be referred to by various names such as first control bits and second control bits.

[0162] 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 transmitting an EHT PPDU, the transmitting STA may set the 3-bit PHY version identifier to a first value. In other words, the receiving STA may determine that the received PPDU is an EHT PPDU based on the PHY version identifier having the first value.

[0163] For example, the version-independent bits of the U-SIG may include a 1-bit UL / DL flag field, where a first value of the 1-bit UL / DL flag field is associated with UL communication and a second value of the UL / DL flag field is associated with DL communication.

[0164] For example, the version-independent bits of the U-SIG may include information about the length of the TXOP and information about the BSS color ID.

[0165] For example, if the EHT PPDU is divided into various types (e.g., EHT PPDU supporting SU, EHT PPDU supporting MU, EHT PPDU related to Trigger Frame, EHT PPDU related to Extended Range transmission, etc.), information regarding the type of EHT PPDU can be included in the version-dependent bits of the U-SIG.

[0166] For example, the U-SIG may include information regarding 1) a bandwidth field containing information regarding the bandwidth, 2) a field containing information regarding the MCS technique applied to the EHT-SIG, 3) an indication field containing information related to whether the dual subcarrier modulation (DCM) technique is applied to the EHT-SIG, 4) a field containing information regarding the number of symbols used for the EHT-SIG, 5) a field containing information regarding whether the EHT-SIG is generated across the entire band, 6) a field containing information regarding the type of EHT-LTF / STF, and 7) a field indicating the length of the EHT-LTF and the CP length.

[0167] Preamble puncturing may be applied to the PPDU in Figure 18. Preamble puncturing refers to applying puncturing to a portion of the entire bandwidth of the PPDU (e.g., the secondary 20 MHz band). For example, when an 80 MHz PPDU is transmitted, the STA applies puncturing to the secondary 20 MHz band of the 80 MHz band, and can transmit the PPDU only through the primary 20 MHz band and the secondary 40 MHz band.

[0168] For example, the preamble puncturing pattern may be preset. For example, when a first puncturing pattern is applied, puncturing may be applied only to a secondary 20 MHz band within an 80 MHz band. For example, when a second puncturing pattern is applied, puncturing may be applied only to one of two secondary 20 MHz bands included in a secondary 40 MHz band within an 80 MHz band. For example, when a third puncturing pattern is applied, puncturing may be applied only to a secondary 20 MHz band included in a primary 80 MHz band within a 160 MHz band (or an 80+80 MHz band). For example, when a fourth puncturing pattern is applied, puncturing may be applied to at least one 20 MHz channel present in a primary 40 MHz band included in a primary 80 MHz band within a 160 MHz band (or an 80+80 MHz band) that does not belong to the primary 40 MHz band.

[0169] Information about preamble puncturing applied to the PPDU may be included in the U-SIG and / or the EHT-SIG, for example, a first field of the U-SIG may include information about the contiguous bandwidth of the PPDU, and a second field of the U-SIG may include information about preamble puncturing applied to the PPDU.

[0170] For example, the U-SIG and EHT-SIG may include information about preamble puncturing based on the following method: If the bandwidth of a PPDU exceeds 80 MHz, the U-SIGs may be individually configured in 80 MHz increments. For example, if the bandwidth of a PPDU is 160 MHz, the PPDU may include a first U-SIG for a first 80 MHz band and a second U-SIG for a second 80 MHz band. In this case, the first field of the first U-SIG may include information about the 160 MHz bandwidth, and the second field of the first U-SIG may include information about the preamble puncturing applied to the first 80 MHz band (i.e., information about the preamble puncturing pattern). Also, the first field of the second U-SIG may include information about the 160 MHz bandwidth, and the second field of the second U-SIG may include information about the preamble puncturing applied to the second 80 MHz band (i.e., information about the preamble puncturing pattern). On the other hand, the EHT-SIG subsequent to the first U-SIG may include information regarding the preamble puncturing applied to the second 80 MHz band (i.e., information regarding the preamble puncturing pattern), and the EHT-SIG subsequent to the second U-SIG may include information regarding the preamble puncturing applied to the first 80 MHz band (i.e., information regarding the preamble puncturing pattern).

[0171] Additionally or alternatively, the U-SIG and the EHT-SIG may include information about preamble puncturing based on the following method: The U-SIG may include information about preamble puncturing for all bands (i.e., information about preamble puncturing patterns). That is, the EHT-SIG does not include information about preamble puncturing, and only the U-SIG may include information about preamble puncturing (i.e., information about preamble puncturing patterns).

[0172] U-SIGs can be configured in 20 MHz increments. For example, when an 80 MHz PPDU is configured, U-SIGs can be duplicated. That is, four identical U-SIGs can be included in an 80 MHz PPDU. PPDUs exceeding the 80 MHz bandwidth can contain different U-SIGs.

[0173] The EHT-SIG in Figure 18 can include control information for the receiving STA. The EHT-SIG can be transmitted via at least one symbol, and one symbol can have a length of 4us. Information regarding the number of symbols used for the EHT-SIG can be included in the U-SIG.

[0174] The EHT-SIG may include the technical features of the HE-SIG-B described in Figures 8 to 9. For example, the EHT-SIG may include a common field and a user-specific field, as in the example of Figure 8. The common field of the EHT-SIG may be omitted, and the number of user-specific fields may be determined based on the number of users.

[0175] As in the example of FIG. 8, the common field of the EHT-SIG and the user-specific field of the EHT-SIG can be coded separately. One user block field included in the user-specific field can include information for two users, while the last user block field included in the user-specific field can include information for one user. That is, one user block field of the EHT-SIG can include up to two user fields. As in the example of FIG. 9, each user field can be associated with MU-MIMO allocation or non-MU-MIMO allocation.

[0176] Similar to the example of FIG. 8, the common field of the EHT-SIG may include CRC bits and Tail bits, where the length of the CRC bits may be determined by 4 bits, and the length of the Tail bits may be determined by 6 bits and set to "000000".

[0177] As in the example of Figure 8, the common field of the EHT-SIG may include RU allocation information. The RU allocation information may refer to information about the locations of RUs to which multiple users (i.e., multiple receiving STAs) are assigned. The RU allocation information may be configured in 8-bit (or N-bit) units, as in Table 1.

[0178] Tables 5 to 7 are examples of 8-bit (or N-bit) information for various RU allocations. The indexes shown in each table are changeable, and some entries in Tables 5 to 7 can be omitted and entries not shown can be added.

[0179] Examples of Tables 5 to 7 relate to information about the locations of RUs allocated to a 20 MHz band. For example, "Index 0" in Table 5 can be used in a situation where nine 26-RUs are individually allocated (e.g., a situation where nine 26-RUs are individually allocated as shown in FIG. 5).

[0180] On the other hand, in an EHT system, multiple RUs can be assigned to one STA. For example, in the case of "Index 60" in Table 6, one 26-RU is assigned to one user (i.e., the receiving STA) on the far left side of the 20 MHz band, and one 26-RU and one 52-RU are assigned to another user (i.e., the receiving STA) on the right side, and five 26-RUs can be assigned individually on the right side of that.

[0181] [Table 5]

[0182] [Table 6]

[0183] [Table 7]

[0184] A mode in which the common field of the EHT-SIG is omitted may be supported. The mode in which the common field of the EHT-SIG is omitted may be referred to as compressed mode. When compressed mode is used, multiple users of the EHT PPDU (i.e., multiple receiving STAs) can decode the PPDU (e.g., the data field of the PPDU) based on non-OFDMA. That is, multiple users of the EHT PPDU can decode the PPDU (e.g., the data field of the PPDU) received via the same frequency band. On the other hand, when non-compressed mode is used, multiple users of the EHT PPDU can decode the PPDU (e.g., the data field of the PPDU) based on OFDMA. That is, multiple users of the EHT PPDU can receive the PPDU (e.g., the data field of the PPDU) via different frequency bands.

[0185] The EHT-SIG may be configured based on various MCS techniques. As described above, information related to the MCS technique applied to the EHT-SIG may be included in the U-SIG. The EHT-SIG may be configured based on the DCM technique. For example, of N data tones (e.g., 52 data tones) allocated for the EHT-SIG, a first modulation technique may be applied to consecutive half of the tones, and a second modulation technique may be applied to the remaining consecutive half of the tones. That is, the transmitting STA may modulate specific control information onto a first symbol based on a first modulation technique and assign it to consecutive half of the tones, and modulate the same control information onto a second symbol based on a second modulation technique and assign it to the remaining consecutive half of the tones. As described above, information (e.g., a 1-bit field) related to whether the DCM technique is applied to the EHT-SIG may be included in the U-SIG.

[0186] The EHT-STF of Figure 18 can be used to improve automatic gain control estimation in a MIMO (multiple input multiple output) or OFDMA environment, and the EHT-LTF of Figure 18 can be used to estimate the channel in a MIMO or OFDMA environment.

[0187] The EHT-STF of FIG. 18 can be configured into various types. For example, the first type of STF (i.e., 1x STF) can be generated based on a first type STF sequence in which non-zero coefficients are arranged at intervals of 16 subcarriers. The STF signal generated based on the first type STF sequence can have a period of 0.8 μs, and the 0.8 μs periodic signal can be repeated five times to become the first type STF having a length of 4 μs. For example, the second type of STF (i.e., 2x STF) can be generated based on a second type STF sequence in which non-zero coefficients are arranged at intervals of 8 subcarriers. The STF signal generated based on the second type STF sequence can have a period of 1.6 μs, and the 1.6 μs periodic signal can be repeated five times to become the second type EHT-STF having a length of 8 μs. An example of a sequence (i.e., an EHT-STF sequence) for configuring the EHT-STF will be presented below. The following sequence can be modified in various manners.

[0188] The EHT-STF can be constructed based on the following M-sequence:

[0189] <Number 1>

[0190] M={-1, -1, -1, 1, 1, 1, -1, 1, 1, 1, -1, 1, 1, -1, 1}

[0191] The EHT-STF for a 20 MHz PPDU can be configured based on the following equation. An example of the following may be a first type (i.e., 1x STF) sequence. For example, the first type sequence may be included in an EHT-PPDU that is not a trigger-based (TB) PPDU. In the following equation, (a:b:c) may refer to an interval defined from a tone index (i.e., subcarrier index) to c tone index at b tone spacing (i.e., subcarrier spacing). For example, Equation 2 below may represent a sequence defined at 16 tone intervals from tone index -112 to 112 index. Since a subcarrier spacing of 78.125 kHz is applied to the EHT-STF, the 16 tone spacing may mean that EHT-STF coefficients (or elements) are arranged at intervals of 78.125*16=1250 kHz. Also, * means multiplication, and sqrt() means the square root.

[0192] <Number 2>

[0193] EHT-STF(-112:16:112)={M}*(1+j) / sqrt(2)

[0194] EHT-STF(0)=0

[0195] The EHT-STF for 40MHz PPDU may be configured based on the following formula: The following example may be a first type (ie, 1x STF) sequence.

[0196] <Number 3>

[0197] EHT-STF(-240:16:240)={M, 0, -M}*(1+j) / sqrt(2)

[0198] The EHT-STF for the 80MHz PPDU may be configured based on the following formula: An example of the following may be a first type (ie, 1x STF) sequence.

[0199] <Number 4>

[0200] EHT-STF(-496:16:496)={M, 1, -M, 0, -M, 1, -M}*(1+j) / sqrt(2)

[0201] The EHT-STF for the 160MHz PPDU may be configured based on the following formula: The following example may be a first type (ie, 1x STF) sequence.

[0202] <Number 5>

[0203] EHT-STF(-1008:16:1008)={M, 1, -M, 0, -M, 1, -M, 0, -M, -1, M, 0, -M, 1, -M}*(1+j) / sqrt(2)

[0204] The sequence for the lower 80 MHz of the EHT-STF for the 80+80 MHz PPDU may be the same as Equation 4. The sequence for the upper 80 MHz of the EHT-STF for the 80+80 MHz PPDU may be configured based on the following equation.

[0205] <Number 6>

[0206] EHT-STF(-496:16:496)={-M, -1, M, 0, -M, 1, -M}*(1+j) / sqrt(2)

[0207] Hereinafter, Equations 7 to 11 relate to an example of a second type (ie, 2x STF) sequence.

[0208] <Number 7>

[0209] EHT-STF(-120:8:120)={M, 0, -M}*(1+j) / sqrt(2)

[0210] The EHT-STF for 40MHz PPDU can be constructed based on the following formula:

[0211] <Number 8>

[0212] EHT-STF(-248:8:248)={M, -1, -M, 0, M, -1, M}*(1+j) / sqrt(2)

[0213] EHT-STF(-248)=0

[0214] EHT-STF(248)=0

[0215] The EHT-STF for 80MHz PPDU can be constructed based on the following formula:

[0216] <Number 9>

[0217] EHT-STF(-504:8:504)={M, -1, M, -1, -M, -1, M, 0, -M, 1, M, 1, -M, 1, -M}*(1+j) / sqrt(2)

[0218] The EHT-STF for 160MHz PPDU can be constructed based on the following formula:

[0219] <Number 10>

[0220] EHT-STF(-1016:16:1016)={M, -1, M, -1, -M, -1, M, 0, -M, 1, M, 1, -M, 1, -M, 0, -M, 1, -M, 1, M, 1, -M, 0, -M, 1, M, 1, -M, 1, -M}*(1+j) / sqrt(2)

[0221] EHT-STF(-8)=0, EHT-STF(8)=0,

[0222] EHT-STF(-1016)=0, EHT-STF(1016)=0

[0223] The sequence for the lower 80 MHz of the EHT-STF for the 80+80 MHz PPDU may be the same as Equation 9. The sequence for the upper 80 MHz of the EHT-STF for the 80+80 MHz PPDU may be configured based on the following equation.

[0224] <Number 11>

[0225] EHT-STF(-504:8:504)={-M, 1, -M, 1, M, 1, -M, 0, -M, 1, M, 1, -M, 1, -M}*(1+j) / sqrt(2)

[0226] EHT-STF(-504)=0,

[0227] EHT-STF(504)=0

[0228] The EHT-LTF can have first, second, and third types (i.e., 1x, 2x, and 4x LTFs). For example, the first, second, and third type LTFs can be generated based on an LTF sequence in which non-zero coefficients are arranged at intervals of 4, 2, or 1 subcarriers. The first, second, and third type LTFs can have time lengths of 3.2, 6.4, and 12.8 μs. In addition, GIs of various lengths (e.g., 0.8, 1, 6, and 3.2 μs) can be applied to the first, second, and third type LTFs.

[0229] Information about the type of STF and / or LTF (including information about the GI applied to the LTF) can be included in the SIG A field and / or SIG B field of FIG. 18, etc.

[0230] The PPDU of FIG. 18 (ie, EHT-PPDU) can be configured based on the examples of FIGS.

[0231] For example, an EHT PPDU transmitted on a 20 MHz band, i.e., a 20 MHz EHT PPDU, can be configured based on the RU in Figure 5. That is, the RU locations of the EHT-STF, EHT-LTF, and data fields included in the EHT PPDU can be determined as shown in Figure 5.

[0232] An EHT PPDU transmitted on the 40 MHz band, i.e., a 40 MHz EHT PPDU, can be configured based on the RU in Figure 6. That is, the RU locations of the EHT-STF, EHT-LTF, and data fields included in the EHT PPDU can be determined as shown in Figure 6.

[0233] Since the RU locations in Figure 6 correspond to 40 MHz, a tone-plan for 80 MHz can be determined by repeating the pattern in Figure 6 twice. That is, the 80 MHz EHT PPDU can be transmitted based on a new tone-plan in which the RUs in Figure 6, but not the RUs in Figure 7, are repeated twice.

[0234] 6 is repeated twice, 23 tones (i.e., 11 guard tones + 12 guard tones) can be configured in the DC region. That is, the tone plan for an 80 MHz EHT PPDU allocated based on OFDMA can have 23 DC tones. In contrast, an 80 MHz EHT PPDU allocated based on non-OFDMA (i.e., a non-OFDMA full bandwidth 80 MHz PPDU) can be configured based on 996RU and can include 5 DC tones, 12 left guard tones, and 11 right guard tones.

[0235] The tone plan for 160 / 240 / 320 MHz can be configured by repeating the pattern of FIG. 6 multiple times.

[0236] The PPDU in FIG. 18 can be determined (or identified) as an EHT PPDU based on the following method.

[0237] The receiving STA can determine that the type of the received PPDU is an EHT PPDU based on the following: For example, if 1) the first symbol after the L-LTF signal of the received PPDU is BPSK, 2) an RL-SIG in which the L-SIG of the received PPDU is repeated is detected, and 3) the result of applying 'modulo 3' to the value of the Length field of the L-SIG of the received PPDU is detected as '0', the received PPDU can be determined to be an EHT PPDU. If the received PPDU is determined to be an EHT PPDU, the receiving STA can detect the type of the EHT PPDU (e.g., SU / MU / Trigger-based / Extended Range type) based on bit information included in the symbols after the RL-SIG in FIG. 18. In other words, the receiving STA can determine that the received PPDU is an EHT PPDU based on: 1) the first symbol after the L-LTF signal, which is the BSPK; 2) the RL-SIG that follows the L-SIG field and is the same as the L-SIG; 3) the L-SIG including a Length field in which the result of applying "modulo 3" is set to "0"; and 4) the 3-bit PHY version identifier (e.g., the PHY version identifier having the first value) of the U-SIG mentioned above.

[0238] For example, the receiving STA can determine that the type of the received PPDU is a HE PPDU based on the following: 1) the first symbol after the L-LTF signal is BPSK, 2) an RL-SIG in which an L-SIG is repeated is detected, and 3) the result of applying 'modulo 3' to the length value of the L-SIG is detected as '1' or '2', the received PPDU can be determined to be a HE PPDU.

[0239] For example, the receiving STA can determine the type of the received PPDU as non-HT, HT, or VHT PPDU based on the following: For example, if 1) the first symbol after the L-LTF signal is BPSK, and 2) an RL-SIG in which an L-SIG is repeated is not detected, the received PPDU can be determined as a non-HT, HT, or VHT PPDU. Also, even if the receiving STA detects a repetition of an RL-SIG, if the result of applying "modulo 3" to the length value of the L-SIG is detected as "0," the received PPDU can be determined as a non-HT, HT, or VHT PPDU.

[0240] In the following example, signals indicated as (transmit / receive / upward / downward) signals, (transmit / receive / upward / downward) frames, (transmit / receive / upward / downward) packets, (transmit / receive / upward / downward) data units, (transmit / receive / upward / downward) data, etc. may be signals transmitted and received based on the PPDU of FIG. 18. The PPDU of FIG. 18 may be used to transmit and receive various types of frames. For example, the PPDU of FIG. 18 may be used for a control frame. Examples of control frames may include a request to send (RTS), a clear to send (CTS), a Power Save-Poll (PS-Poll), a BlockACKReq, a BlockAck, a Null Data Packet (NDP) announcement, and a Trigger Frame. For example, the PPDU of FIG. 18 may be used for a management frame. Examples of management frames 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. 18 can be used for a data frame. For example, the PPDU in Fig. 18 can also be used to simultaneously transmit at least two or more of a control frame, a management frame, and a data frame.

[0241] FIG. 19 shows a modified example of the transmitting device and / or receiving device of this specification.

[0242] Each device / STA in sub-drawings (a) / (b) of Figure 1 can be modified as shown in Figure 19. The transceiver 630 in Figure 19 can be the same as the transceivers 113 and 123 in Figure 1. The transceiver 630 in Figure 19 can include a receiver and a transmitter.

[0243] The processor 610 in Figure 19 can be the same as the processors 111 and 121 in Figure 1. Alternatively, the processor 610 in Figure 19 can be the same as the processing chips 114 and 124 in Figure 1.

[0244] The memory 150 in Figure 19 can be the same as the memories 112, 122 in Figure 1. Alternatively, the memory 150 in Figure 19 can be a separate external memory that is different from the memories 112, 122 in Figure 1.

[0245] 19, a power management module 611 manages power to the processor 610 and / or the 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 can be displayed on the display 613. A SIM card 615 can be an integrated circuit used to securely store an international mobile subscriber identity (IMSI) and associated keys used to identify and authenticate subscribers on mobile phone devices such as mobile phones and computers.

[0246] 19, the speaker 640 can output sound-related results processed by the processor 610. The microphone 641 can receive sound-related inputs for use by the processor 610.

[0247] FIG. 20 shows an example of an HE-PPDU.

[0248] The illustrated L-STF2000 can include short training OFDM symbols (orthogonal frequency division multiplexing symbols), which can be used for frame detection, automatic gain control (AGC), diversity detection, and coarse frequency / time synchronization.

[0249] L-LTF2010 can include long training OFDM symbols (orthogonal frequency division multiplexing symbols), which can be used for fine frequency / time synchronization and channel estimation.

[0250] The L-SIG2020 can be used to transmit control information. The L-SIG2020 can include information about a data transmission rate and a data length. The L-SIG2020 can also be repeatedly transmitted. That is, the L-SIG2020 can be configured in a repeated format (e.g., referred to as an R-LSIG).

[0251] The HE-SIG-A2030 may contain control information common to receiving stations.

[0252] Specifically, the HE-SIG-A2030 includes: 1) a DL / UL indicator; 2) a BSS color field, which is a BSS identifier; 3) a field indicating the remaining time of the current TXOP interval; 4) a bandwidth field indicating whether 20, 40, 80, 160, or 80+80 MHz is available; 5) a field indicating the MCS technique to be applied to the HE-SIG-B; 6) a field indicating whether the HE-SIG-B is modulated using a dual subcarrier modulation technique for the MCS; 7) a field indicating the number of symbols used for the HE-SIG-B; 8) a field indicating whether the HE-SIG-B is generated across the entire band; 9) a field indicating the number of symbols for the HE-LTF; 10) a field indicating the length of the HE-LTF and the CP length; 11) a field indicating whether additional OFDM symbols are present for LDPC coding; 12) a PE (Packet 1) a field indicating control information related to the HE-SIG-A (Encoding Extension), 2) a field indicating information related to the CRC field of the HE-SIG-A, etc. Specific fields of the HE-SIG-A may be added or omitted. Also, in environments other than the multi-user (MU) environment, some fields may be added or omitted.

[0253] Additionally, HE-SIG-A2030 can be composed of two parts: HE-SIG-A1 and HE-SIG-A2. HE-SIG-A1 and HE-SIG-A2 included in HE-SIG-A can be defined in the following format structure (fields) by PPDU. First, the HE-SIG-A field of the HE SU PPDU can be defined as follows:

[0254] [Table 8]

[0255] [Table 9]

[0256] [Table 10]

[0257] [Table 11]

[0258] Also, the HE-SIG-A field of the HE MU PPDU can be defined as follows:

[0259] [Table 12]

[0260] [Table 13]

[0261] [Table 14]

[0262] [Table 15]

[0263] Also, the HE-SIG-A field of the HE TB PPDU can be defined as follows:

[0264] [Table 16]

[0265] [Table 17]

[0266] [Table 18]

[0267] [Table 19]

[0268] [Table 20]

[0269] As described above, HE-SIG-B2040 can be included only if it is a PPDU for multiple users (MUs). Essentially, HE-SIG-A2020 or HE-SIG-B2030 can include resource allocation information (or virtual resource allocation information) for at least one receiving STA.

[0270] The technical features of the STA-assisted channel bonding in this specification are described below.

[0271] For example, in an IEEE 802.11n system, two 20 MHz channels can be bonded to implement 40 MHz channel bonding, and in an IEEE 802.11ac system, 40 / 80 / 160 MHz channel bonding can be implemented.

[0272] For example, a STA can perform channel bonding for a primary 20 MHz channel (P20 channel) and a secondary 20 MHz channel (S20 channel). A backoff count / counter can be used in the channel bonding process. The backoff count value can be selected as a random value and decremented during the backoff interval. Generally, when the backoff count value reaches 0, the STA can attempt to connect to the channel.

[0273] A STA performing channel bonding determines whether the S20 channel has maintained an idle state for a certain period (e.g., point coordination function interframe space (PIFS)) when the P20 channel is determined to be in an idle state during the backoff interval and the backoff count value for the P20 channel becomes 0. If the S20 channel is in an idle state, the STA can perform bonding of the P20 channel and the S20 channel. That is, the STA can transmit a signal (PPDU) through a 40 MHz channel (i.e., a 40 MHz bonding channel) including the P20 channel and the S20 channel.

[0274] Figure 21 shows an example of channel bonding. As shown in Figure 21, a primary 20 MHz channel and a secondary 20 MHz channel can form a 40 MHz channel (primary 40 MHz channel) through channel bonding. That is, the bonded 40 MHz channel can include a primary 20 MHz channel and a secondary 20 MHz channel.

[0275] Channel bonding can be performed when the channels adjacent to the primary channel are in an idle state. That is, the primary 20 MHz channel, secondary 20 MHz channel, secondary 40 MHz channel, and secondary 80 MHz channel can be bonded in sequence. If the secondary 20 MHz channel is determined to be busy, channel bonding may not be performed even if all other secondary channels are in an idle state. Also, if the secondary 20 MHz channel is idle and the secondary 40 MHz channel is determined to be busy, channel bonding may be performed only for the primary 20 MHz channel and the secondary 20 MHz channel.

[0276] In the following, STA-assisted preamble puncturing in this specification will be described.

[0277] For example, in the example of Figure 21, if the primary 20MHz channel, secondary 40MHz channel, and secondary 80MHz channel are all in an idle state and the secondary 20MHz channel is in a busy state, bonding to the secondary 40MHz channel and the secondary 80MHz channel is impossible. In this case, the STA can construct a 160MHz PPDU and transmit a signal via the idle channel by puncturing the preamble (e.g., L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF, EHT-SIG, EHT-STF, EHT-LTF, etc.) transmitted via the secondary 20MHz channel. In other words, the STA can perform preamble puncturing on a portion of the band of the PPDU. Information regarding preamble puncturing (e.g., information regarding the 20 / 40 / 80 MHz channel / band to which puncturing is applied) can be included in the signal field of the PPDU (e.g., HE-SIG-A, U-SIG, EHT-SIG).

[0278] Hereinafter, technical features of the STA-supported Multi-link (ML) of this specification will be described.

[0279] The STAs (APs and / or non-AP STAs) in this specification can support multi-link (ML) communication. ML communication can refer to communication that supports multiple links. Links related to ML communication can include channels (e.g., 20 / 40 / 80 / 160 / 240 / 320 MHz channels) in the 2.4 GHz band disclosed in FIG. 15, the 5 GHz band disclosed in FIG. 16, and the 6 GHz band disclosed in FIG. 17.

[0280] The multiple links used for ML communication can be configured 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. Alternatively, 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 5 GHz / 6 GHz band) and at least one channel in the 5 GHz band (or 2.4 GHz / 6 GHz band). Meanwhile, at least one of the multiple links supported by one STA for ML communication is a channel to which preamble puncturing is applied.

[0281] An STA can perform ML setup to perform ML communication. The ML setup can be performed based on management frames or control frames such as a Beacon, a Probe Request / Response, or an Association Request / Response. For example, information about the ML setup can be included in an element field included in a Beacon, a Probe Request / Response, or an Association Request / Response.

[0282] When ML setup is complete, enabled links for ML communication can be determined. STAs can perform frame exchange via at least one of the enabled links. For example, the enabled link can be used for at least one of management frames, control frames, and data frames.

[0283] 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 Multi-Link Device (MLD) including the first STA for the first link and the second STA for the second link. For example, one AP supporting two links can be represented as one AP MLD including the first AP for the first link and the second AP for the second link. Also, one non-AP supporting two links can be represented as one non-AP MLD including the first STA for the first link and the second STA for the second link.

[0284] Below, more specific features regarding the ML setup are described.

[0285] An MLD (AP MLD and / or non-AP MLD) can transmit information about links that the MLD can support through ML setup. The link information can be configured in various ways. For example, the link information 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 / maximum number of uplink / downlink links supported by the MLD (or STA); 3) information about the location / bandwidth / resources of uplink / downlink links supported by the MLD (or STA); 4) information about frame types (e.g., management, control, data) available or selected for at least one uplink / downlink link; 5) ACK policy information available or selected for at least one uplink / downlink link; and 6) information about traffic identifiers (TIDs) available or selected for at least one uplink / downlink link. TIDs indicate the priority of traffic data and are expressed using eight different values ​​according to conventional WLAN standards. That is, eight TID values ​​can be defined corresponding to four access categories (AC) according to the conventional WLAN standard (AC_BK (background), AC_BE (best effort), AC_VI (video), and AC_VO (voice)).

[0286] For example, it may be preset that all TIDs are mapped 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 TIDs can be used for ML communication.

[0287] Through ML setup, multiple links that can be used by a transmitting MLD and a receiving MLD related to ML communication can be set, which can be called "enabled links." An "enabled link" can be called in various ways, such as a first link, a second link, a transmitting link, a receiving link, etc.

[0288] After the ML setup is completed, the MLD can update the ML setup. For example, if an update to information about a link is required, the MLD can transmit information about a new link. The information about the new link can be transmitted based on at least one of a management frame, a control frame, and a data frame.

[0289] According to one embodiment, MLD may include non-AP MLD and AP-MLD. Non-AP MLD and AP-MLD may be distinguished according to the function of an AP (access point). Non-AP MLD and AP-MLD may be distinguished physically or logically. For example, if an MLD performs the function of an AP, it may be called AP MLD, and if the MLD performs the function of an STA, it may be called non-AP MLD.

[0290] In the following description, an MLD has one or more connected STAs and one MAC service access point (SAP) that communicates with an upper link layer (Logical Link Control, LLC). An MLD can refer to a physical device or a logical device. Hereinafter, a device can refer to an MLD.

[0291] Furthermore, the MLD may include at least one STA connected to each link of the multilink. For example, a processor in the MLD may control the at least one STA. For example, the at least one STA may be configured and operated independently. Each of the at least one STA may include a processor and a transceiver. For example, the at least one STA may operate independently, regardless of the processor in the MLD.

[0292] For the sake of convenience, the following description will be made assuming that an MLD (or a processor of an MLD) controls at least one STA, but this is not intended to be limiting. As mentioned above, the at least one STA may transmit and receive signals independently of the MLD.

[0293] According to one embodiment, an AP MLD or a non-AP MLD may be configured with a structure having multiple links. In other words, a non-AP MLD can support multiple links. A non-AP MLD can include multiple STAs. Each of the multiple STAs can have its own link.

[0294] The EHT standard (802.11be standard) considers the MLD (Multi-Link Device) structure, in which one AP / non-AP MLD supports several links, as its key technology. STAs included in a non-AP MLD can transmit information to other STAs in the non-AP MLD via a single link. This reduces the overhead of frame exchange. It also increases the link utilization efficiency of STAs and reduces power consumption.

[0295] FIG. 22 shows an example of the structure of a non-AP MLD.

[0296] Referring to Figure 22, a non-AP MLD can be configured in a structure having multiple links. In other words, a non-AP MLD can support multiple links. A non-AP MLD can include multiple STAs. Each of the multiple STAs can have its own link. Although Figure 22 shows an example of a non-AP MLD structure, an AP MLD structure can also be configured in the same way as the example of the non-AP MLD structure shown in Figure 22.

[0297] For example, a non-AP MLD may include STA1, STA2, and STA3. STA1 may operate on link1, which may be included in the 5 GHz band. STA2 may operate on link2, which may be included in the 6 GHz band. STA3 may operate on link3, which may be included in the 6 GHz band. The bands that link1 / 2 / 3 include are merely examples and may be included in 2.4, 5, and 6 GHz.

[0298] In the case of AP / non-AP MLD that supports multi-link, each AP in AP MLD and each STA in non-AP MLD can be connected to each link through the link setup process, and the connected link can be changed or reconnected to another link by AP MLD or non-AP MLD depending on the situation.

[0299] In addition, in the EHT standard, a link can be classified as an anchored link or a non-anchored link to reduce power consumption. An anchored link or a non-anchored link 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.

[0300] 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 anchored links. A non-AP MLD can be used by selecting one or more of its anchored links from the anchored link list (a list of anchored links supported by the AP MLD).

[0301] For example, an anchored link can be used not only for frame exchange for synchronization but also for non-data frame exchange (e.g., beacon and management frames), and a non-anchored link can be used only for data frame exchange.

[0302] Non-AP MLD can only monitor the anchored link to receive beacons and management frames during idle periods. Therefore, in the case of non-AP MLD, it must be connected to at least one anchored link to receive beacons and management frames. The one or more anchored links must always be maintained 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 idle periods when the channel / link is not in use. This has the effect of reducing power consumption.

[0303] In the following specification, for efficient link connection, a protocol in which AP MLD or non-AP MLD dynamically recommends or requests link reconnection depending on the situation may be proposed. Also, in the following specification, an anchored link reconnection protocol that takes into account the characteristics of not only general links but also anchored links used for the purpose of power reduction may be additionally proposed.

[0304] Example of link change and reconnection

[0305] According to one embodiment, each link between the AP MLD and the non-AP MLD can be determined through an association or (re)association process. At this time, the AP MLD and the non-AP MLD can perform frame exchange through the connected link. A specific example of connecting the AP MLD and the non-AP MLD through the link setup process can be described with reference to FIG. 23.

[0306] FIG. 23 shows an example in which AP MLD and non-AP MLD are connected through a link setup process.

[0307] 23, the AP MLD can include AP1, AP2, and AP3. The non-AP MLD can include STA1 and STA2. AP1 and STA1 can be connected via link1. AP2 and STA2 can be connected via link2.

[0308] For example, AP1 and STA1 may be connected via link1 through a first link setup process. AP2 and STA2 may be connected via link2 through a second link setup process. As another example, AP MLD and non-AP MLD may be connected via a single link setup process. In other words, AP MLD and non-AP MLD may be connected via link1 and link2 based on a single link setup process.

[0309] As described above, each AP and STA can exchange frames via the connected links, and information on other APs or STAs on different links can be transmitted and received via one link.

[0310] However, after this link setup process, AP MLD or non-AP MLD can request link change or reconnection for more efficient frame exchange (for example, load balancing or interference avoidance) depending on the situation / environment.

[0311] An example of link modification or reconnection can be explained with reference to FIG.

[0312] FIG. 24 shows an example where a Link is changed or reconnected.

[0313] 24, STA2 is previously connected to AP2. After that, excessive data load may occur on AP2. STA2 may then reconnect to AP3, which has a relatively light data load. In this case, AP MLD and non-AP MLD can perform efficient data exchange.

[0314] FIG. 25 shows a specific example in which a Link is changed or reconnected.

[0315] 25, AP1 of the AP MLD can be connected to STA1 of the non-AP MLD via link 1. AP2 of the AP MLD can be connected to STA2 of the non-AP MLD via link 2. Thereafter, STA2 can attempt / request connection with AP3 through a link change or reassociation, and STA2 can be connected to AP3 via link 2 based on the link change or reassociation.

[0316] According to one embodiment, AP MLD and non-AP MLD can transmit / receive / exchange various information about the current link and information about the link state. Therefore, AP MLD and non-AP MLD can select a link suitable for transmitting / receiving signals based on the various information about the current link and the link state. For example, the various information about the current link can include information about the data traffic load for each link and the channel access capability between links. For example, the link state can be set to disable or enable.

[0317] Hereinafter, in this specification, the process in which an AP MLD / non-AP MLD negotiates with a non-AP MLD / AP MLD to request a change or reconnection to another link other than the connected link in order to improve performance may be referred to as "link switching negotiation." The term "link switching negotiation" may be variously referred to and may be subject to change.

[0318] In the following, the link change or reconnection process can be explained separately for cases where AP MLD requests and cases where non-AP MLD requests.

[0319] Example of AP MLD requesting link change or reconnection

[0320] According to one embodiment, the AP MLD can request a link change or reassociation to the non-AP MLD for efficient data transmission. For example, for load balancing, based on the data traffic of each AP, the AP MLD can request the STA to change or reassociate to a more efficient link.

[0321] For example, the AP MLD can calculate / confirm / determine a link suitable for the STA of the non-AP MLD 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 the STA (or the non-AP MLD) to change or reconnect to the link based on the data traffic load information for each AP and / or channel access capability information between each link.

[0322] As described above, when requesting a link change, the AP MLD can transmit the link information it considers most appropriate to the non-AP MLD via a request message. For example, the request message can include a beacon or a management frame.

[0323] In relation to the above-described embodiment, an element or field containing link information that is considered to be most suitable may be newly proposed. The newly proposed element or field may be defined as a "recommended link." The "recommended link" is merely an example, and the name of the specific element or field may be changed.

[0324] 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) can be 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.

[0325] According to one embodiment, the recommend link (element / field) can be optionally included in a 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). As another example, the STA can execute a connection request to a link different from the indicated link based on the element / field (i.e., the recommend link) and additional information it has.

[0326] A specific signal exchange process of AP MLD and non-AP MLD according to the above embodiment can be described with reference to FIG.

[0327] FIG. 26 shows the operation of AP MLD and non-AP MLD for link change or reconnection.

[0328] 26, when STA2 is connected to AP2 via link 2, a lot of data traffic may be collected at AP2. In other words, when STA2 is connected to AP2 via link 2, a lot of data traffic may be generated at AP2.

[0329] The AP MLD (or AP2) can request the non-AP MLD (or STA2) to reassociate with AP3, which has relatively few STAs connected to it. Generally, a message for requesting reassociation is sent to the STA (i.e., STA2) that desires to reassociate, but can also be sent to any STA (i.e., other STA) depending on the situation (e.g., channel conditions or link status). In other words, the STA to which the request message (e.g., Link switching request frame) for requesting reassociation is sent can be changed based on the channel conditions or link status.

[0330] For example, if the STA (i.e., STA2) receives the request message for requesting reassociation and accepts the request, it can transmit a response message (e.g., a Link switching response frame) of "Accept." As another example, if the STA (i.e., STA2) rejects the request, it can transmit a response message of "Decline."

[0331] The response message is generally sent by the STA (i.e., STA2) accepting the reconnection to the existing link (the link connected before the reconnection), but it can also be sent via any link (i.e., another STA) using the multi-link characteristics.

[0332] If STA2 accepts the link reassociation request, after sending a response message, STA2 can disconnect from the existing AP2 and request link reassociation from AP3. In this case, the reassociation 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 via Link2.

[0333] On the other hand, if STA2 rejects the link reassociation request, STA2 and AP2 can continue to use the existing connected link (i.e., link2).

[0334] According to one embodiment, when an AP requests a STA to change its link, if the AP recommends a suitable link, the STA may or may not change its link to the recommended link. For example, the AP can use the above-mentioned "recommend link" to recommend a suitable link to the STA.

[0335] For example, the STA may approve a link change as a response message to a request message for requesting reassociation with 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.

[0336] Therefore, the AP needs to inform the STA whether or not the response message is accepted. To this end, the AP can send a Confirmation message (e.g., a link switching confirmation frame) to the STA in response to the STA's response message (e.g., a Link Switching Response frame).

[0337] The specific operations of AP MLD and non-AP MLD in the above-described embodiment can be explained with reference to FIG.

[0338] FIG. 27 shows the operation of AP MLD and non-AP MLD for link change or re-association.

[0339] 27, AP2 may request a link change from STA2, including recommended link information. In other words, AP2 may transmit a link switching request frame including recommended link information to STA2.

[0340] STA2 can transmit whether or not to accept the link request via a Link switching Response frame.

[0341] For example, if link switching is accepted, STA2 may transmit a link switching response frame including link information to be changed. In this case, the link information to be changed may or may not be the same as the recommended link.

[0342] As 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 whether or not the link is finally approved. This message may be called a Link Switching Confirmation Frame.

[0343] For example, AP2 may accept a link change to a link specified by STA2 via a Link Switching Confirmation frame. STA2 may attempt to change its link to a link specified by itself based on the Link Switching Confirmation frame.

[0344] As another example, AP2 may refuse to change the link to the link specified by STA2 via the Link Switching Confirmation frame. STA2 and AP2 may maintain the connection with the existing link without changing the link.

[0345] The embodiment shown in Figure 27 can also be applied when an AP transmits a Link switching request frame without including recommended link information. For example, if an AP (e.g., AP2) transmits a Link switching request frame to a STA (e.g., STA2) without including recommended link information, the STA can directly specify a new link based on its own information and then respond to the AP via a Link switching response frame. In this case, the AP must also ultimately transmit a Link switching Confirmation frame for approval. Therefore, the embodiment in which the AP transmits a Link switching Confirmation frame can be applied even when recommended link information is not included in the Link switching request frame.

[0346] Example of non-AP MLD requesting link change or reconnection

[0347] According to one embodiment, the non-AP MLD can request a link change or re-association 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 re-association to the AP MLD.

[0348] FIG. 28 shows the operation of AP MLD and non-AP MLD for link change or reassociation.

[0349] Referring to Figure 28, 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 link switching response frame can be transmitted and received via the link to be changed, but is not limited to this. The link switching request frame or link switching response frame can also be transmitted and received via various links, not just the link to be changed.

[0350] Non-AP MLD can request a link change or reassociation through various methods. Three methods for non-AP MLD to request a link change or reassociation are proposed below. Specifically, the three methods are a solicited method, an unsolicited method, and a general method.

[0351] 1) Solicited methodA method in which a non-AP MLD requests various information for link (re)selection from an AP MLD and requests link (re)selection based on the information received through the request. According to one embodiment, the method in which an STA requests information about other APs in the associated AP MLD can be used in various cases, not just when re-establishing a link. Therefore, an AP that receives an information request message can transmit all of the capability information, BSS parameter information, critical parameters, and / or operation element information for all APs in the AP MLD. The above examples can all be applied to the embodiments described below.

[0352] 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, and requests link (re)selection based on the information received through this. According to one embodiment, the method in which an STA requests information about other APs in the associated AP MLD can be used in various cases, not just when re-establishing a link. Therefore, an AP that receives an information request message can transmit all of the capability information, BSS parameter information, critical parameters, and / or operation element information for all APs in the AP MLD. The above examples can all be applied to the embodiments described below.

[0353] 3) General method : A method in which non-AP MLD requests link (re)selection without additional information based on information previously obtained through a beacon frame, etc.

[0354] 1)Solicited method

[0355] In the following, first an embodiment relating to the aforementioned solicited method can be described.

[0356] According to one embodiment, the non-AP MLD can request information for selecting a link suitable for the AP MLD before link change or reconnection. To select a suitable link, the STA can use data load information for each AP or capability information for each link (or information on other links).

[0357] For example, the Capability information for each link can be periodically transmitted by being included in a Beacon frame.

[0358] As another example, link-specific capability information may be optional and not be included in the beacon frame transmitted periodically. Alternatively, to reduce frame overhead, only information on the link to which the STA is connected or some related links may be received. Alternatively, 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.

[0359] In the above case, non-AP MLD can request the latest information of link-specific capability information and AP MLD's link-specific information. The link of the link-specific capability information and 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 in the 11ax standard), a management frame, a probe response frame, a PS-Poll frame, or a null frame can be used to request / send the latest information. Alternatively, a separate new frame can be defined to request / send the latest information.

[0360] According to one embodiment, in order to request updated information on per-link capability information and per-link AP MLD information, the STA may transmit a request message to the AP requesting information necessary for link reselection. For example, the previously defined probe request frame may be reused for the request message. As another example, a new frame for the request message may be defined.

[0361] According to one embodiment, the STA may specify necessary specific information via 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 for all links or BSS load information for a specific link. In this case, the AP may transmit only the information specified by the STA via a response message. Specific examples of specific information request and response may be described through examples of IOM definitions and operations.

[0362] As another example, the STA may request all capability information (eg, including information on other links) currently held by the AP MLD via the request message.

[0363] 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 can be defined / configured in various ways. For example, the AP can transmit all information or designated information based on a separate field or bitmap.

[0364] Generally, a message requesting information from AP MLD can be sent via the STA that desires to reassociate, but depending on the situation (channel conditions or link conditions), it can also be sent to any STA (i.e., other STA).

[0365] Upon receiving the request message, the AP MLD can transmit a response message (i.e., information message) including the latest information required for link reselection (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) must respond using a probe response frame as the response message.

[0366] The response message can also be generally transmitted via the AP that received the request message, but can also be transmitted to any AP (ie, other AP) using the multi-link characteristics.

[0367] Alternatively, the AP MLD can send a "recommend link" element recommending a suitable link for the STA together with a response message containing the various information mentioned above (e.g., the latest information required for link reselection).

[0368] Hereinafter, the above-mentioned request message and response message may be described as an information request message and an information response message to distinguish them from a request message for link change and a response message for link change.

[0369] Based on the information included in the information response message, the STA can reselect a suitable link and request a link change or reassociation to the AP MLD via a link change request message. The link change request message can include AP information and link information to which the STA will reassociate.

[0370] Upon receiving the request message, the AP MLD can send an "Accept" response message if it accepts the request, or a "Decline" response message if it rejects the request.

[0371] 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 a response message. On the other hand, if the request is rejected, the STA can continue to use the existing connected link.

[0372] A specific example of the operation of AP MLD and non-AP MLD according to the Solicited method can be described with reference to FIG.

[0373] FIG. 29 shows the operation of AP MLD and non-AP MLD for link change or reconnection.

[0374] 29, when STA2 of the non-AP MLD wants to reselect a connected link, STA2 can transmit an Info Request message to the AP MLD via Link 2. Upon receiving this, the AP MLD can transmit an Info Response message including information necessary for link reselection of the non-AP MLD. Based on the information included in the Info Response message, STA2 of the non-AP MLD can transmit a link change request message (i.e., link switching request frame) to AP2 of the AP MLD. Thereafter, STA2 can receive the link change response message (i.e., link switching request frame) and perform link (re)setup for the link change.

[0375] The information request embodiments proposed in this specification can also be used / applied when a STA requests necessary information from an AP. If the frame (e.g., a beacon) that the STA receives from the AP contains insufficient information, the STA can request the AP for the missing information. For example, if the AP does not include information about other links and only transmits information about connected links, or transmits only information about whether the information about other links is updated, the STA can request the AP for the missing information.

[0376] A specific example of the above embodiment can be explained with reference to FIG.

[0377] FIG. 30 shows the operation of non-AP MLD to request information about other APs.

[0378] Referring to FIG. 30, AP MLD (or AP1 to AP3) can transmit only information regarding whether or not information on other APs (i.e., links) is 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 / obtain information regarding other APs based on the Info response message.

[0379] For example, the Beacon may not include other AP information (such as BSS load) in the AP MLD, or AP2 may transmit only information regarding whether or not the other AP information has been updated (such as version / update version).

[0380] STA2 needs information about AP1 (or information about AP1). STA2 can request the necessary information through AP2. STA2 can obtain the information about AP1 through a response message to the request. STA2 can use the information about AP1 when reselecting an appropriate link for link switching. For example, a frame for link switching can be set in various ways.

[0381] In the following, a new element / field can be proposed that contains information for a non-AP MLD STA to select a suitable link.

[0382] For example, 'STA ratio per Link' (element / field) can be proposed. 'STA ratio per Link' can include information on the ratio of the number of STAs connected per Link. A specific example of 'STA ratio per Link' can be described with reference to FIG. 31.

[0383] FIG. 31 shows a specific example of the STA ratio per link.

[0384] Referring to FIG. 31, 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.

[0385] For example, if a total of 50 STAs are connected to an AP MLD with three links, 10 STAs can be connected to Link 1 and 20 STAs can be connected to Link 2. The AP MLD can transmit information about the STAs connected to each link via the STA ratio per Link (element / field) as a value or ratio (%) to the non-AP MLD.

[0386] For example, if information about the STAs connected to each link is expressed as a value, Link1 can be expressed / set as 10 and Link2 can be expressed / set as 20. Therefore, the value of the STA ratio per link1 can be set to 10. Also, the value of the STA ratio per link2 can be set to 20.

[0387] As another example, if information about the STAs connected to each link is expressed as a ratio, Link1 can be expressed / set as 20 (10 / 50)% and Link2 can be expressed / set as 40 (20 / 50)%. Therefore, the value of STA ratio per link1 can be set to 20. Also, the value of STA ratio per link2 can be set to 40.

[0388] The above example is merely an example, and information about STAs connected to each link can be set in various ways. In addition to the above example, information about STAs connected to each link can be set to relative values.

[0389] Based on the information about the STAs connected to each link described above, the STA can check / obtain the number and ratio of STAs connected to each link and use this as information for link selection.

[0390] According to an embodiment, various information / elements / fields may be included in the information response message in addition to the above-mentioned "STA ratio per Link" (element / field). For example, the following information / elements / fields may be included in the information response message:

[0391] -BSS load information for each AP

[0392] -STR Capability information between links

[0393] -TXOP information for each link

[0394] -NAV information for each link

[0395] -Recommended Link information (i.e., "recommend Link" element)

[0396] -Link-specific connected STA ratio information (i.e., 'STA ratio per Link' element)

[0397] -Others

[0398] In addition to the above-mentioned information / element / field, various information required for link selection can be included in the information response message and transmitted.

[0399] Upon receiving the information as described above, the STA can select an AP to change or re-associate with based on the received information and then transmit a request message to request link re-association. The AP MLD that receives the request message can transmit an "Accept" response message if it accepts the request. The AP MLD can transmit a "Decline" response message if it rejects the request.

[0400] If the request is accepted, the AP can perform frame exchange with the reselected AP via the link after sending the response message, whereas if the request is rejected, the STA can continue to use the existing link.

[0401] 2)Unsolicited method

[0402] Unlike the Solicited method in which the non-AP MLD directly requests additional information, the Unsolicited method allows the AP MLD to transmit additional information to the non-AP MLD via a Beacon frame or a separate frame (e.g., a QoS data frame field (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 requesting additional information from the non-AP MLD. As another example, a new frame may be defined as a frame for transmitting additional information to the non-AP MLD.

[0403] For example, if the beacon period is somewhat long, the non-AP MLD may lack the necessary information for link switching or may not have the latest information. Therefore, the AP can transmit a frame containing the AP MLD's link capability information to the non-AP MLD. Thereafter, the non-AP STA can obtain the latest information on the AP MLD's link capability. The frame can be transmitted periodically or aperiodically.

[0404] For example, if the frame is transmitted periodically, the AP may transmit a frame to share the latest information of the AP at a fixed time interval. In this case, the time interval should be shorter than the period of the beacon transmitted by the AP. Also, if an FILS Discovery frame is used as the frame, the frame may be transmitted every 20 μs. 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 via the values ​​of the 'periodic' field and 'interval' field / subfield of the IOM capability element.

[0405] 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 may be transmitted to the connected STA. In this case, the STA may maintain the latest information on the link capability.

[0406] In the above example, since the non-AP STA does not send a separate request message for acquiring link capability, the frame exchange overhead is relatively less than that of the solicited method. Also, since the STA can receive updated information every time the main information is updated, the STA can effectively use the received information.

[0407] A specific example of the operation of AP MLD and non-AP MLD according to the Unsolicited method can be described with reference to FIG.

[0408] FIG. 32 shows the operation of AP MLD and non-AP MLD for link change or reconnection.

[0409] Referring to FIG. 32, the AP MLD can transmit essential information required for link reselection to the non-AP in a separate frame (eg, an Info message) without a separate request message from the non-AP MLD.

[0410] According to one embodiment, unlike in Figure 32, the AP MLD can also transmit information about link capability to the STA via a field in a DL frame (e.g., a QoS data frame) that it transmits to the non-AP MLD without a separate request message from the non-AP MLD. The operations of the AP MLD and non-AP MLD according to this embodiment can be described with reference to Figure 33.

[0411] FIG. 33 shows the operation of AP MLD and non-AP MLD for link change or reconnection.

[0412] Referring to FIG. 33, AP2 can transmit information about the other AP (or information about the other AP) to STA2 based on a DL frame (i.e., DL1). In other words, the DL frame can include information about the other AP. For example, the information about the other AP can be included in the A-Control field of the 802.11ax standard. According to the above embodiment, since an existing DL frame is used without a separate message, it is possible to reduce frame overhead. If the critical information of the other AP is changed and real-time information is required, update information can be transmitted via a separate message as in the embodiment of FIG. 32.

[0413] For example, the critical information of an AP may include the following A to Q.

[0414] A.Inclusion of a Channel Switch Announcement element

[0415] B.Inclusion of an Extended Channel Switch Announcement element

[0416] C.Modification of the EDCA parameters element

[0417] D.Inclusion of a Quiet element

[0418] E.Modification of the DSSS Parameter Set

[0419] F.Modification of the CF Parameter Set element

[0420] G.Modification of the HT Operation element

[0421] H.Inclusion of a Wide Bandwidth Channel Switch element

[0422] I.Inclusion of a Channel Switch Wrapper element

[0423] J.Inclusion of an Operating Mode Notification element

[0424] K.Inclusion of a Quiet Channel element

[0425] L.Modification of the VHT Operation element

[0426] M.Modification of the HE Operation element

[0427] N.Insertion of a Broadcast TWT element

[0428] O.Inclusion of the BSS Color Change Announcement element

[0429] P.Modification of the MU EDCA Parameter Set element

[0430] Q.Modification of the Spatial Reuse Parameter Set element

[0431] Therefore, the non-AP MLD can obtain the latest link capability information regardless of the beacon frame period. The non-AP MLD can select a suitable link during link switching based on the received information. Based on the received information, the STA can request the AP MLD to change or reconnect to the link by reselecting a suitable link. The request message can include information about the AP and link 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.

[0432] If the request is accepted, the AP can perform link (re)setup on the link of the reselected AP through frame exchange after sending a response message. On the other hand, if the request is rejected, the STA can continue to use the existing connected link.

[0433] 3)General method

[0434] 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., per-link STR capability information, link state (enable / disable) information, etc.) contained in previously received beacons or management frames.

[0435] Unlike the solicited method, a STA can directly send a request message to the AP MLD for link modification or reassociation without separately requesting information from the AP MLD. The request message can include AP information and link information to which the STA will reassociate. The AP MLD that receives the request message can send an "Accept" response message if it accepts the request, or a "Decline" response message if it rejects it.

[0436] If the request is accepted, the AP can perform frame exchange with the reselected AP via the link after sending the response message, whereas if the request is rejected, the STA can continue to use the existing link.

[0437] An example of specific AP MLD and non-AP MLD operations according to the general method can be described with reference to FIG.

[0438] FIG. 34 shows the operation of AP MLD and non-AP MLD for link change or reconnection.

[0439] 34, STA2 may directly request a link change for QoS reasons. If STA2 already has information received from the AP MLD (e.g., information received via a Beacon frame or a Management frame) or has already determined the link it desires to reconnect to, STA2 can request a link change or reconnection without a separate information request.

[0440] 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 frame accepts the change, it can send an "approved" link switching response frame to STA3 via existing Link2. Thereafter, non-AP MLD STA2 can reconnect to AP3 after performing a link (re)setup process.

[0441] Example of changing and reconnecting an anchored link

[0442] According to one embodiment, the AP MLD can support an anchored link. If the AP MLD supports an anchored link, there are additional considerations to be made in the above-described embodiment for link modification and reconnection.

[0443] An AP MLD can support one or more anchored links and can provide information about one or more anchored links to a non-AP MLD via the anchored link list information / element. A non-AP MLD can select and use one or more links from this anchored link list as its own anchored links. The remaining links that are not selected as anchored links can operate as non-anchored links.

[0444] Anchored links and non-anchored links have a trade-off relationship in terms of power consumption and data load. That is, if a non-AP MLD uses one anchored link, power consumption can be reduced, but it is difficult to guarantee the QoS of data transmission (especially data for beacons and management frames). In contrast, if multiple anchored links are used, data transmission QoS can be guaranteed, but power consumption can be reduced.

[0445] Therefore, non-AP MLD must dynamically request reselection of the anchored link for efficient data exchange. Therefore, hereinafter, an embodiment for non-AP MLD to dynamically request anchored link change / reselection can be proposed.

[0446] First, the MLD structure supporting the Anchored Link can be explained with reference to FIG.

[0447] FIG. 35 shows an example of an MLD structure that supports an anchored link.

[0448] Referring to Figure 35, AP MLD can use two of the five links (i.e., AP1 and AP4) as anchored links. Non-AP MLD can select Link 1 from the two links used as anchored links and use it as one anchored link. The remaining links of non-AP MLD can be connected to non-anchored links (Link 2 and Link 3). In other words, non-AP MLD must always monitor Link 1 to receive beacons and management frames.

[0449] According to one embodiment, STA1 may request to change the anchored link it has previously used to AP4 for reasons such as load balancing, etc. To change the anchored link, the above-described embodiment regarding link switching may be applied.

[0450] However, anchored links are limited to a portion of the links supported by AP MLD. Therefore, AP MLD can have a separate anchored link list. A non-AP MLD (or STA) must select one of the links included in the anchored link list and request a change or reassociation. Furthermore, since a non-AP MLD must have at least one anchored link, it must take this into consideration when requesting a link change or reassociation.

[0451] For the above-described embodiment, the AP MLD must provide 'Anchored Link List' information in addition to the non-AP MLD. This can be included in the frame in the form of a new element or field. The name of the 'Anchored Link List' described above is merely an example and can be set / expressed in various ways.

[0452] - "Anchored Link List" (element / field) : List information of anchored links supported by the current AP MLD. For example, the list information of anchored links supported by the current AP MLD can be indicated / set to one or more link IDs or AP BSS values, etc. A non-AP MLD must be connected to at least one anchored link among the links included in the list.

[0453] The above-mentioned information (e.g., the "Anchored Link List" (element / field)) can be included in an existing Beacon or management frame and transmitted, or in the case of the above-mentioned Solicited method, can be included in an Info response message and transmitted to the non-AP MLD.

[0454] Therefore, when a non-AP MLD requests a change to the Anchored Link it uses, it must first know the Anchored Link List information it currently supports. If it does not know the Anchored Link List information or wants to obtain the most up-to-date information, it can obtain it from the AP MLD using the Solicited method.

[0455] Based on the Anchored Link List information, the STA can request a change or re-association to only one link in the Anchored Link List. If the STA requests a change or re-association to another link not included in the list, the AP MLD can send a rejection message to the STA.

[0456] When changing or reconnecting an anchored link, there are additional considerations to be made in addition to the existing link change method. When a non-AP MLD STA changes its anchored link, it can be broadly divided into two cases.

[0457] The first is when a STA already connected to an anchored link changes to another anchored link in the AP MLD for reasons such as load balancing (AP change for the anchored link). The second is when a STA connected to an anchored link is disabled for reasons such as power status, and another STA in a non-AP MLD reconnects to the anchored link (STA change for the anchored link).

[0458] In the first case, the operation is similar / identical to the embodiment for link change and reconnection described above. However, when the STA reselects a link, it must select from the links in the Anchored Link List supported by the AP MLD. If another link is selected, the AP MLD can send a rejection response message.

[0459] In the second case, additional considerations are required. An example for the second case can be illustrated via FIG.

[0460] FIG. 36 shows examples of situations where an anchored link needs to be changed or reconnected.

[0461] 36, the non-AP MLD STAs may be disabled for various reasons (e.g., power off, etc.) In this case, since STA2 and STA3 are currently connected to non-anchored links, one of the two STAs must be reconnected to an anchored link.

[0462] As shown in FIG. 36, when the non-AP MLD needs to reconnect the anchored link, the non-AP MLD can attempt to reconnect one of STA2 and STA3 to the anchored link.

[0463] For example, if the non-AP MLD knows information about the Anchored Link List supported by the AP MLD, the non-AP MLD can select an appropriate link and request a link change.

[0464] As another example, if a non-AP MLD does not have information about the Anchored Link List supported by an AP MLD, the non-AP MLD can obtain the information from the AP MLD via an Info request, select a suitable link, and request a link change.

[0465] A specific example of the operation of AP MLD and non-AP MLD according to the above embodiment can be described with reference to FIG.

[0466] FIG. 37 shows the operation of AP MLD and non-AP MLD for anchored link change or reconnection.

[0467] 37, when STA1, which was connected to the anchored link, is disabled, the non-AP MLD needs to establish a new anchored link connection. In this case, the non-AP MLD can disconnect the existing non-anchored link connection with AP3 for STA3 and attempt to reconnect to the anchored link.

[0468] For example, STA3 may attempt to connect to AP1, which was previously used as an anchored link. As another example, STA3 may attempt to connect to new AP4 based on various information.

[0469] The process of selecting a new anchored link can be performed in the same or similar manner as the above-described embodiment for link change or reconnection. For example, STA3 can request reconnection by selecting an anchored link recommended by the AP, or by directly selecting an anchored link. After the anchored link reconnection is complete, STA3's link can operate as an anchored link.

[0470] An element / field containing information about the Anchored Link

[0471] According to one embodiment, if information about an Anchored Link supported by the AP MLD is changed or if a STA directly requests information about the Anchored Link, the AP MLD can send the information (i.e., information about the changed Anchored Link or information about the Anchored Link requested by the STA) to the non-AP MLD.

[0472] For example, the information is information related to the currently used Anchored Link, and may be included in a Beacon frame and transmitted, or may be included in a separate Management frame and transmitted.

[0473] The information about the anchored link may include the 'Anchored Link List' element indicating the anchored link supported by the AP MLD and information on whether or not the anchored link is used by each STA of the non-AP MLD.

[0474] In the following, a new element including information about the above-mentioned Anchored Link can be proposed. The newly proposed element can be configured / set as follows.

[0475] 1) "Anchored Link Indication" element (or field) The 'Anchored Link Indication' element can include information on whether or not an anchored link is used for each STA connected to the AP MLD. That is, the 'Anchored Link Indication' element is an element / field that indicates whether or not an anchored link is used for each link or STA of a non-AP MLD.

[0476] 2) "STA ratio per Anchored Link" element(or field)The 'STA ratio per Anchored Link' element can include information about the ratio or number of STAs connected per Anchored Link. However, only STAs that use a link as an Anchored Link can be considered. In other words, even if AP MLD supports a first link as an Anchored Link, STAs that use the first link as a Non-Anchored Link are not included in the STAs connected per Anchored Link.

[0477] According to one embodiment, the element can be included as additional information in the frame if necessary in all the processes of the above-described embodiments for modifying or reconnecting an anchored link.

[0478] A specific example of the element can be explained with reference to FIG.

[0479] 38 and 39 show specific examples of elements for reconnecting an Anchored Link.

[0480] 38 and 39, information about the Anchored Link can be transmitted via an Anchored Link List element (or field), an Anchored Link Indication element (or field), and / or an STA ratio per Anchored Link element (or field). In other words, an element for Anchored Link reconnection can include an Anchored Link List element (or field), an Anchored Link Indication element (or field), and / or an STA ratio per Anchored Link element (or field).

[0481] According to one embodiment, the Anchored Link List element may include link list information supported by the current AP MLD, as described above. For example, the link list information supported by the current AP MLD may be indicated based on a link ID, AP BSS information, etc. In other words, the link list supported by the current AP MLD may be configured / set based on a link ID or AP BSS information.

[0482] According to one embodiment, the Anchored Link Indication element may include information on whether an anchored link is used for each STA of non-AP MLD. For example, information on whether an anchored link is used for each STA of non-AP MLD may be indicated / displayed via an indication bitmap for each link (i.e., FIG. 36). As another example, whether an anchored link is used for all STAs may be indicated / displayed via one bitmap (i.e., FIG. 37).

[0483] For example, if the link ID-based indication bitmap indicates information about whether an anchored link is in use, the STA can check the current anchored link based on the value of the anchored link list element. Therefore, the STA can check the ratio of STAs connected to each anchored link. In this case, the indication bitmap field for non-anchored links can be omitted to reduce overhead.

[0484] When a bit in the bitmap has a value of 1, the bit may indicate that the link currently connected to the STA is an anchored link. When a bit in the bitmap has a value of 0, the bit may indicate that the link currently connected to the STA is a non-anchored link. The embodiment in which a bitmap is used to indicate whether or not an anchored link is connected per STA is merely an example, and information regarding whether or not an anchored link is connected per STA may be transmitted through various embodiments.

[0485] According to one embodiment, the ratio of STAs to all links supported by AP MLD can be transmitted. According to one embodiment, the STA ratio per Anchored Link element can include information about the ratio or number of STAs actually using each anchored link as an anchored link. For example, the information is displayed only for anchored links indicated / displayed in the Anchored Link List element, which can reduce overhead.

[0486] An example of setting the value of the STA ratio per Anchored Link element can be described below.

[0487] For example, an AP MLD may include five APs (i.e., AP1 to AP5), where AP1 may be connected to a STA via link 1, AP2 may be connected to a STA via link 2, AP3 may be connected to a STA via link 3, AP4 may be connected to a STA via link 4, and AP5 may be connected to a STA via link 5.

[0488] AP MLD can support two of the five links (i.e., link1 to link5) as anchored links. Link1 and link4 can be supported / used as anchored links.

[0489] There are a total of 10 STAs connected to Link1 (or AP1), and 7 STAs use Link1 as their anchored link. This can be expressed as 70% in percentage terms, or as 7 in value terms.

[0490] A total of 20 STAs are connected to Link4 (or AP4), and 5 STAs use Link4 as their anchored link. This can be expressed as 25% in percentage terms, or as 5 in value terms.

[0491] The STA ratio per Anchored Link element can be transmitted together with the above-mentioned STA ratio per Link element information, thereby transmitting more accurate information to the STA. Generally, an anchored link can have relatively more data traffic than a non-anchored link, so the STA ratio per Anchored Link element can be used as useful information for a STA reselecting an anchored link.

[0492] Based on the above information (or elements), the non-AP MLD can check whether the link to which it is connected is an anchored link, the connection ratio of STAs for each anchored link, and the ratio at which the anchored link is actually used.

[0493] Additionally, if the AP MLD transmits information about other links, i.e., all links, through the above-mentioned element, the STA can check the connection ratio and actual usage ratio for each STA for all anchored links of the AP MLD based on one frame. Therefore, the above information (or element) can be used when the STA reselects the anchored link to be used.

[0494] Therefore, according to the embodiment for anchored link change or reselection, by using not only various link information (e.g., BSS load information for each AP or STR capability information for each link, etc.) used in the embodiment for link change or reselection, but also the above-mentioned information on the anchored link (e.g., anchored link list information, anchored link usage indication information for each STA, or actual STA usage ratio information for each anchored link, etc.), it is possible to perform more appropriate anchored link change or reconnection.

[0495] Signaling for indicating link change and reconnection methods

[0496] To support the proposed method, a mutual agreement process is required through negotiation between AP MLD and non-AP MLD. For this purpose, a signaling method for enabling the proposed method is proposed in the following specification.

[0497] First, a new element can be proposed to indicate the proposed method. Although an embodiment regarding signaling for indicating a link change and reconnection method will be described below, the embodiment can also be applied to an embodiment regarding signaling for indicating an anchored link change and reconnection method.

[0498] The signaling process for indicating the link change and reassociation method can be performed during or after multi-link setup. Furthermore, the signaling process for indicating the link change and reassociation method can use new elements proposed below. For example, the elements can be included in the (re)association frame of the conventional standard or a new frame.

[0499] IOM (Information Obtain Method) Capability Element

[0500] The IOM Capability Element may include information on whether to enable a method for obtaining additional information for multilink. For example, when AP MLD and non-AP MLD exchange messages for operational agreement during a multilink setup process (e.g., a capability negotiation process), an IOM capability value may be present in the element of the message. The presence of an IOM capability value in the element of the message may mean that the IOM capability is supported.

[0501] According to one embodiment, when an AP MLD supports the IOM capability, the AP internally receives information about other APs and has the information about the other APs. An MLD that does not share information about other APs cannot support the IOM capability.

[0502] According to one embodiment, when the value of the IOM capability element is set to a first value (e.g., 1), the IOM capability element may indicate that the IOM is activated to operate with the indicated function, whereas when the value of the IOM capability element is set to a second value (e.g., 0), the IOM capability element may indicate that the IOM is deactivated.

[0503] According to one 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 as described below. However, the fields / elements added to the IOM capability element may be configured to be different depending on whether the AP MLD requests a link change or the non-AP MLD requests a link change. Also, at least some of the fields / elements added to the IOM capability element may be omitted. For example, among the fields / elements added to the IOM capability element, a field / element containing information that does not need to be indicated may be omitted.

[0504] Examples of various fields / elements defined / configured to obtain additional information about the multilink are described below. The various fields / elements described below may be configured independently, or two or more fields / elements may be combined and transmitted through various frames.

[0505] Method type (or Method) field / element

[0506] The Method type field / element (hereinafter referred to as the 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 the 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 the proposed methods (e.g., the Solicited method, the Unsolicited method, and the General method).

[0507] As an example, if the value of the Method field / element is a first value (e.g., 0), the Solicited method can be indicated / used. If the value of the Method field / element is a second value (e.g., 1), the Unsolicited method can be indicated / used. If the value of the Method field / element is a third value (e.g., 2), the General method can be indicated / used. If the value of the Method field / element is a fourth value (e.g., 3), both the Solicited method and the Unsolicited method can be indicated / used.

[0508] As another example, 1 bit can be used as the Method field / element. In this case, the Solicited method can be indicated / used based on the value of the Method field / element being a first value (e.g., 0). The Unsolicited method can be indicated / used based on the value of the Method field / element being a second value (e.g., 1).

[0509] As another example, 2 bits can be used as the Method field / element, in which case, each method can be designated as being used alone or in combination.

[0510] Info range field / element

[0511] The information range (Info range) field can be used to indicate the range of information when information is provided to non-AP MLD in IOM. In other words, the information range (Info range) field can contain information about the range of information when information is provided to non-AP MLD in IOM.

[0512] 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 information is provided. If the value of the Info range field is a second value (e.g., 1), the Info range field may indicate that all information (or the entire information) is provided.

[0513] According to one embodiment, a subfield for indicating the range of information to be provided (e.g., all information or partial information) may be included in the information range field. For example, the subfield for indicating the range of information to be provided may be defined / set as an all / partial subfield.

[0514] According to one embodiment, a subfield may be newly proposed to indicate whether to receive all information or only changed information among all the information. In other words, the newly proposed subfield may indicate whether to receive all information or only changed information among all the information.

[0515] For example, a subfield for indicating whether to receive all information or only changed information among all the information can be defined / set as an only updated subfield.

[0516] If a STA desires to receive only changed information, the value of the only updated subfield can be set to 1. In other words, if a STA desires to receive only changed information, the STA can set the value of the only updated subfield to 1. For example, in the solicited method, when a STA requests information, the AP (or AP MLD) can transmit only changed information (i.e., updated information) from the requested information. As another example, in the unsolicited method, the AP can notify only changed information within the information range set by the STA.

[0517] 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 can also be defined / set to receive only changed information.

[0518] According to the above embodiment, the range of information that a STA can request can be set to updated information or all information. In this case, a STA that does not want a lot of frame overhead can request to receive only changed information. Therefore, various overheads can be reduced.

[0519] Link condition field / element

[0520] The link condition field can be used to indicate a specific link to be requested. In other words, the link condition field can include information about the specific link to be requested. The link condition field can be used when the STA desires to receive only specific link information from the AP.

[0521] The link condition field may be represented by a link identifier (e.g., Link ID, BSS ID). In other words, the link condition field may include information about the link identifier (e.g., Link ID, BSS ID). In other words, the link identifier may be used to identify the link for which information is to be obtained.

[0522] For example, if a STA connected to Link1 wishes to request only information about Link2 and Link3 from the AP, the STA can request information about Link2 and Link3 from the AP by indicating Link2 and Link3 in the link condition field. For example, if the value of the info range field is 1, all information corresponding to Link2 and Link3 can be transmitted. As another example, if the value of the info range field is 0, some information specified by the STA for Link2 and Link3 can be transmitted. According to one embodiment, the some information specified by the STA can be determined through the following info condition field.

[0523] According to one embodiment, if the value of the link condition field is absent or 0, the AP can determine that there is no link condition. Therefore, the AP can provide / transmit information about all links to the STA.

[0524] Info condition field / element

[0525] The Info condition field can be used to indicate the type of specific information requested. In other words, the Info condition field can be used when the STA desires to receive only specific information from the AP.

[0526] For example, the information condition field can be used only if the info range field is set to 0. As another example, the information condition field can be used by the STA to indicate specific information even when the info range field is not present.

[0527] For example, in the information condition field, information that can be specified by the STA (e.g., BSS Load, STR Capability, etc.) can be displayed as a bitmap. For example, the type of information provided by the AP and the indication method or order within the bit can be set in various ways.

[0528] According to one embodiment, the information condition field can be used together with the link condition field described above. According to one embodiment, the information condition field can transmit request information of various conditions to the STA (or AP) based on various field / element combinations.

[0529] According to one embodiment, an element of an existing standard may be reused for a STA to request specific information. For example, a Request IE or an Extended Request IE may be used for a STA to request specific information. Specific examples of the Request IE or Extended Request IE may be described below.

[0530] FIG. 40 shows a specific example of the request element format.

[0531] Referring to Figure 40, a request element may include an element ID field, a length field, and / or a Requested Element IDs field. For example, the element ID field may include information indicating that it is a request element. The length field may include information about the number of octets after the length field. The Requested Element IDs field may include information about the element IDs to be requested.

[0532] FIG. 41 shows a specific example of the Extended Request element format.

[0533] Referring to Figure 41, it may include an element ID field, a length field, an Element ID extension field, a Requested Element ID field, and / or a Requested Element IDs Extensions field. The element ID field and the length field may be set similarly to the element ID field and the length field of Figure 40. The Element ID extension field may form an Extended Element ID in combination with the Element ID field. The Requested Element ID field may include one of the element IDs used to indicate an extended element. The Requested Element IDs Extensions field may include a 1-octet element ID extension value.

[0534] Referring to Figures 40 and 41, the element (request element or Extended Request element) can be used to request specific information in a probe request frame or an information request frame.

[0535] For example, when the STA indicates a list of information for which it wishes to receive a response in the "requested element IDs" field, the AP can transmit the corresponding information in a probe response frame or an information response frame.

[0536] Therefore, in the embodiments of the present specification, the element (request element or extended request element) can be reused / used as an indicator for requesting specific information. For example, the element can be used to request desired information of a desired link together with a link identifier (e.g., link identifier).

[0537] For example, the STA may use a request element and a link identifier to request BSS load information of AP2. The STA may indicate an element ID for the BSS load information through the request element. The STA may also indicate AP2 through the link identifier. Therefore, the STA may request BSS load information of AP2 based on the request element and the link identifier.

[0538] According to one embodiment, the element ID information can be used to indicate specific information of a specific AP through various combinations with the link identifier information. According to one embodiment, even when a new frame is defined to request information that is not included in an existing frame, the Request element and / or Extended Request element can be used / reused.

[0539] In the previous standard, the PV1 Probe Response Option element was used to request specific information. Therefore, in an embodiment, the PV1 Probe Response Option element can be used to indicate specific information.

[0540] FIG. 42 shows a specific example of the PV1 Probe Response Option element format.

[0541] 42, the PV1 Probe Response Option element can be used to request optional information as a probe request for information desired by the STA. Frequently used information can be indicated in the probe response option bitmap.

[0542] However, the EHT standard requires that multi-link information be provided in consideration of MLD. Therefore, the STA can request specific information for various combinations of specific links using a link identifier along with a bitmap indicator such as those shown in Tables 21 to 26.

[0543] According to one embodiment, optional information (e.g., STR capability) can be newly defined along with multi-link in the EHT standard. Therefore, when the PV1 Probe response option element is used / reused, a bitmap for information that is newly defined in the EHT standard or that needs to be additionally acquired can be newly or additionally defined. The Probe response option bitmap can be set as shown in Tables 21 to 26 below.

[0544] If the i-th bit of the probe response group bitmap is set to 1, the probe response option bitmap subfield i can be included in the PV1 Probe Response Option element.

[0545] Table 21 shows an example of Probe Response Option Bitmap subfield 0.

[0546] Table 22 shows an example of Probe Response Option Bitmap subfield 1.

[0547] Table 23 shows an example of the Probe Response Option Bitmap subfield2.

[0548] Table 24 shows an example of Probe Response Option Bitmap subfield 3.

[0549] Table 25 shows an example of Probe Response Option Bitmap subfield 4.

[0550] Table 26 shows an example of Probe Response Option Bitmap subfield 5.

[0551] [Table 21]

[0552] [Table 22]

[0553] [Table 23]

[0554] [Table 24]

[0555] [Table 25]

[0556] [Table 26]

[0557] According to one embodiment, Probe Response Option Bitmap subfield 6 or 7 may be newly defined / configured to request specific information regarding multilinks.

[0558] Transmission periodic field / element

[0559] If a STA desires to receive information in an unsolicited manner, it can indicate via a transmission periodicity field whether it will receive messages containing the information periodically or aperiodically.

[0560] For example, if the STA desires to receive the information aperiodically, the AP can be notified of the updated information whenever an update occurs to the information of other APs.

[0561] As another example, if the STA instructs to receive the information periodically, the STA may receive a message containing the information at a periodic interval set by the STA.

[0562] According to one embodiment, the transmission periodicity field may be set to 1 bit. When the value of the transmission periodicity field is set to 1, the STA may receive / acquire information through a periodic method of periodically receiving messages. When the value of the transmission periodicity field is set to 0, the STA may receive / acquire information through a method of aperiodically receiving messages.

[0563] Transmission interval field / element

[0564] According to one embodiment, if a STA wants to periodically receive information from other APs, 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 must be set shorter than the beacon transmission interval. For example, if a FILS discovery frame is used, the interval must be set to 20 us.

[0565] As described above, it may be defined in a separate field within the element that indicates the transmission period, or may be defined in a subfield within the transmission periodic field.

[0566] According to one embodiment, the fields / elements defined / set to obtain additional information about the multilink are not limited to the above-mentioned fields / elements, and various other fields / elements may also be set.

[0567] Therefore, an MLD (AP MLD or non-AP MLD) can indicate IOM capability through negotiation between the AP MLD and non-AP MLD using at least one of the elements / fields detailed in the multi-link setup process. Also, after the multi-link setup is completed, the MLDs can update the agreement between the MLDs through a separate message exchange.

[0568] According to one embodiment, when the IOM capability is activated, AP MLD and non-AP MLD can operate according to the embodiment for link change and reassociation.

[0569] Below, examples of the operation of AP MLD and non-AP MLD when the IOM capability is activated will be 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 inclusion of the above-mentioned field / element in the IOM Capability element is merely an example, and the field / element can also be sent as an independent field / element.

[0570] For example, during 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 multi-link setup, the non-AP MLD operates using the Solicited method and can request information for 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 links as a response message only when it receives a request message from a 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.

[0571] As 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, even without a separate request message, the AP can send the BSS load information of Link 2 to the STA via a separate message.

[0572] As 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 to the STA only the updated (changed) information of the BSS load information of all APs in the AP MLD that the STA connected to when requesting information, in a response message.

[0573] According to one embodiment, AP MLD and non-AP MLD can activate the proposed IOM method through the signaling method proposed in this specification during or after multi-link setup. In addition, AP MLD and non-AP MLD can limit the range and type of information requested through various field values ​​in the IOM Capability element.

[0574] According to one embodiment, the IOM operation can be performed after precise operation negotiation between MLDs through the above-mentioned IOM signaling method, but the IOM operation can also be performed by implementing the MLD without a separate signaling process, which may mean operating by implementing the AP MLD or non-AP MLD without negotiation between the AP MLD and non-AP MLD.

[0575] Based on the above-described embodiment, AP MLD and non-AP MLD can operate, but if MLD performs IOM operation without a separate signaling exchange, the following restrictions may occur.

[0576] 1) Restrictions on the Solicited Method: If info sharing between APs in AP MLD is not supported, when a STA requests information about other links, it cannot respond.

[0577] 2) Restrictions on the Unsolicited Method: The AP can determine which STAs require additional link information and provide them with a separate message (e.g., beacon period, etc.). Therefore, the STAs cannot predict in advance whether they will receive this information.

[0578] If MLD implements IOM without a separate signaling method, the operation process will be simplified, but there is a problem that the above-mentioned restrictions may occur.

[0579] According to one embodiment, a method for requesting information about multilinks can be configured based on the agreement between AP MLD and non-AP MLD, which is performed using the IOM capability element described above. In contrast, in the case of the Solicited method, an STA can request specific information that is not agreed upon and temporarily acquire that information. In this case, when an STA dynamically sends a request message, it can include the requested information (e.g., IOM capability information) in the request.

[0580] For example, AP MLD and non-AP MLD may be agreed upon during or after multi-link setup, and the STA may receive information from the AP based on the agreed content. However, the STA may temporarily request information about a specific AP or specific parameter information about the AP. In this case, when requesting information, the STA may transmit an "IOM capability" element in a request frame (e.g., a probe request frame, a (re)association frame, or a new frame) including an indication of the information it wishes to request. The AP may transmit / provide a response message to the STA based on the request frame, including the information the STA wishes to request. According to one embodiment, if a field in the IOM capability element is omitted, the AP may provide information to the STA based on the previously agreed content.

[0581] Therefore, the MLD (AP MLD or non-AP MLD) can perform negotiation between the AP MLD and non-AP MLD using the above-mentioned elements during or after the multi-link setup process. The non-AP MLD can agree on the information to be provided (or received) based on the negotiation and receive it. In addition, the STA can temporarily receive only the requested information by including instructions for the information it wishes to receive in the request message and transmitting it. However, if special instructions are omitted from the request message, the non-AP MLD and AP MLD can operate based on the instructions that were agreed upon.

[0582] According to one embodiment, if the agreement content needs to be changed after the multi-link setup is completed, the non-AP MLD and AP MLD can update the agreement content between the MLDs through a separate message exchange.

[0583] FIG. 43 is a flowchart illustrating the operation of a multilink device.

[0584] 43, in step S4310, the multilink device may transmit a request frame including an information field for requesting all elements included in an element set designated for the second link. According to one embodiment, the multilink device may transmit a request frame including an information field for requesting all elements included in an element set designated for the second link to a first AP of the multilink device via a first STA (Access Point).

[0585] For example, a multilink device may be connected to an AP multilink device via multiple links, including a first link. The multilink device may include multiple STAs associated with the multiple links. For example, a first STA among the multiple STAs may be connected to the first link. In other words, the first STA may operate on the first link. The first STA may also be connected to a first AP of the AP multilink device via the first link.

[0586] For example, the plurality of links and the second link may be included within the 2.4 GHz, 5 GHz, and 6 GHz bands.

[0587] According to an embodiment, the request frame may include identifier (ID) information for the second link. The identifier information for the second link may be configured as 4-bit information. For example, the identifier for the first link and the identifier for the second link may be represented by 4 bits.

[0588] According to one embodiment, a set of elements that can be requested via the request frame may be referred to as an element set. Therefore, all elements included in the element set may refer to all elements that can be requested via the request frame. In other words, a multilink device may request all information about the second link based on the request frame.

[0589] For example, the set of elements specified for the second link may include elements related to capabilities for the second link or elements related to parameters for the second link.

[0590] According to one embodiment, the request frame may include 1-bit information indicating that all elements included in the designated element set are requested. In other words, an information field for requesting all elements included in the designated element set for the second link may be set to 1-bit information.

[0591] For example, the 1-bit information may be set to a first value. In other words, a multilink device may indicate that it requests all elements included in the specified element set by setting the 1-bit information to a first value (e.g., 1).

[0592] In addition, the multi-link device can indicate that it requests some elements included in the specified element set by setting the 1-bit information to a second value (e.g., 0).

[0593] According to one embodiment, the request frame may further include an information field for requesting all elements included in an element set designated for a third link among the plurality of links. That is, the multi-link device may request all elements included in an element set designated for a second link and all elements included in an element set designated for a third link via the request frame.

[0594] In step S4320, the multi-link device may receive a response frame based on the request frame. According to one embodiment, the multi-link device may receive a response frame from the first AP via the first STA based on the request frame.

[0595] According to one embodiment, the response frame may include all elements included in the element set specified for the second link.

[0596] According to one embodiment, a second link can be distinguished from the plurality of links. If the second link is distinguished from the plurality of links, the multilink device can transmit the request frame to request elements related to links not currently connected to the multilink device. Based on the request frame, the multilink device can receive elements related to links not currently connected to the multilink device via a response frame.

[0597] The multi-link device may transmit a second request frame to request a change of the link to which the first STA is connected from the first link to the second link based on the response frame, and thereafter, the multi-link device may perform a procedure to change the link to which the first STA is connected from the first link to the second link based on the second request frame.

[0598] Based on the procedure for changing the link to which a first STA is connected from the first link to the second link, the first STA can establish a connection with a second AP of the AP multilink device. For example, the second AP can operate on the second link. The first STA can also operate on the second link. In other words, based on the procedure, the first STA can establish a connection with the second AP via the second link.

[0599] According to one embodiment, a second link may be included in the plurality of links. If the second link is included in the plurality of links, the multilink device may transmit the request frame via the first link to request elements related to the currently connected link. In other words, the multilink device may transmit the request frame via the first link to request elements related to a different link. Based on the request frame, the multilink device may receive elements related to the currently connected links, excluding the first link, via a response frame.

[0600] FIG. 44 is a flowchart illustrating the operation of the AP multilink device.

[0601] 44, the AP multilink device may receive a request frame including an information field for requesting all elements included in an element set designated for the second link. According to one embodiment, the AP multilink device may receive a request frame including an information field for requesting all elements included in an element set designated for the second link from a first STA of the multilink device via a first AP.

[0602] According to one embodiment, an AP multilink device may be connected to a multilink device via multiple links. For example, a second link may be included in the multiple links. As another example, the second link may be distinct from the multiple links.

[0603] For example, an AP multilink device may be connected to a multilink device via multiple links, including a first link. The AP multilink device may include multiple APs related to the multiple links. For example, a first AP among the multiple APs may be connected to the first link. In other words, the first AP may operate on the first link. The first AP may also be connected to a first STA of the multilink device via the first link.

[0604] For example, the plurality of links and the second link may be included within the 2.4 GHz, 5 GHz, and 6 GHz bands.

[0605] According to an embodiment, the request frame may include identifier (ID) information for the second link. The identifier information for the second link may be configured as 4-bit information. For example, the identifier for the first link and the identifier for the second link may be represented by 4 bits.

[0606] According to one embodiment, a set of elements that can be requested through the request frame may be referred to as an element set. Accordingly, all elements included in the element set may refer to all elements that can be requested through the request frame.

[0607] For example, the set of elements specified for the second link may include elements related to capabilities for the second link or elements related to parameters for the second link.

[0608] According to one embodiment, the request frame may include 1-bit information indicating that all elements included in the designated element set are requested. In other words, an information field for requesting all elements included in the designated element set for the second link may be set to 1-bit information.

[0609] For example, the 1-bit information may be set to a first value. In other words, a multilink device may indicate that it requests all elements included in the specified element set by setting the 1-bit information to a first value (e.g., 1).

[0610] Therefore, the AP multilink device can confirm that the multilink device has requested all elements included in the specified element set based on the 1-bit information.

[0611] According to one embodiment, the request frame may further include an information field for requesting all elements included in an element set designated for a third link among the plurality of links.

[0612] In step S4420, the AP multilink device may transmit a response frame based on the request frame. According to one embodiment, the AP multilink device may transmit a response frame to the first STA via the first AP based on the request frame.

[0613] According to one embodiment, the response frame may include all elements included in the element set specified for the second link.

[0614] According to one embodiment, a second link may be distinguished from the plurality of links. If the second link is distinguished from the plurality of links, the AP multilink device may receive the request frame to request elements related to links not currently connected to the AP multilink device. Based on the request frame, the AP multilink device may transmit elements related to links not currently connected to the AP multilink device via a response frame.

[0615] According to one embodiment, the AP multilink device may receive a second request frame for requesting a change of a link connected to a first STA from the first link to the second link based on the response frame, and thereafter, the AP multilink device may perform a procedure for changing a link connected to the first STA from the first link to the second link based on the second request frame.

[0616] A second AP of the AP multi-link device can establish a connection with the first STA based on the procedure for changing the link to which the first STA is connected from the first link to the second link. For example, the second AP can operate on the second link, and the first STA can also operate on the second link. In other words, the first AP can establish a connection with the first STA via the second link based on the procedure.

[0617] According to an embodiment, a second link may be included in the plurality of links. If the second link is included in the plurality of links, the AP multi-link device may receive a request frame via a first link of the plurality of links to request elements related to the remaining links excluding the first link. Based on the request frame, the AP multi-link device may transmit elements related to the remaining links excluding the first link of the currently connected links via a response frame.

[0618] The technical features of the present specification may be applied to various devices and methods. For example, the technical features of the present specification may be implemented / supported by the device of FIG. 1 and / or FIG. 19. For example, the technical features of the present specification may be applied to only a part of FIG. 1 and / or FIG. 19. For example, the technical features of the present specification may be 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. 19. For example, the apparatus of the present specification may include a processor and a memory coupled to the processor, wherein the processor transmits a request frame including an information field for requesting all elements included in an element set specified for a second link to a first AP of an AP multi-link device via a first STA (Station) operating on a first link, and receives a response frame from the first AP via the first STA based on the request frame, wherein the response frame may be configured to include all elements included in the element set specified for the second link.

[0619] The technical features of the present specification may be embodied based on a computer readable medium (CRM). For example, the CRM proposed by the present specification may be encoded as at least one computer program including instructions. When executed by at least one processor, the instructions may cause the at least one processor to perform operations including: transmitting a request frame, including an information field for requesting all elements included in an element set designated for a second link, to a first AP of an AP multilink device via a first station (STA) operating on a first link; and receiving a response frame from the first AP via the first STA based on the request frame, the response frame including all elements included in the element set designated for the second link. The instructions stored in the CRM of the present specification may be executed by at least one processor. The at least one processor associated with the CRM of the present specification may be processors 111 and 121 or processing chips 114 and 124 of FIG. 1, or processor 610 of FIG. 19. Meanwhile, the CRM in this specification may be the memories 112 and 122 in FIG. 1, the memory 620 in FIG. 19, or a separate external memory / storage medium / disk.

[0620] The technical features of the present specification described above can be applied to various applications and business models, for example, for wireless communication in devices supporting artificial intelligence (AI).

[0621] Artificial intelligence refers to the field that studies artificial intelligence or the methodologies that can create it, while machine learning refers to the field that defines various problems that are dealt with in the field of artificial intelligence and studies the methodologies to solve them. Machine learning can also be defined as an algorithm that improves its performance for any task through constant experience with that task.

[0622] An artificial neural network (ANN) is a model used in machine learning and can refer to a general model with problem-solving capabilities that is composed of artificial neurons (nodes) that form a network through synaptic connections. An artificial neural network can be defined by the connection pattern between neurons in different layers, a learning process that updates model parameters, and an activation function that generates output values.

[0623] An artificial neural network can have an input layer, an output layer, and optionally one or more hidden layers. Each layer contains one or more neurons, and the artificial neural network can include synapses connecting the neurons. In an artificial neural network, each neuron can output a function value of an activation function in response to an input signal, weights, and biases input via a synapse.

[0624] Model parameters are parameters determined through learning, such as synaptic connection weights and neuron biases, while hyperparameters are parameters that must be set before learning in a machine learning algorithm, such as the learning rate, number of iterations, mini-batch size, and initialization function.

[0625] The goal of training an artificial neural network can be considered as determining model parameters that minimize a loss function. The loss function can be used as an index for determining optimal model parameters during the training process of the artificial neural network.

[0626] Machine learning can be classified into supervised learning, unsupervised learning, and reinforcement learning depending on the learning method.

[0627] Supervised learning refers to a method of training an artificial neural network when labels for training data are given, and a label can refer to the correct answer (or result value) that the artificial neural network should infer when training data is input to the artificial neural network. Unsupervised learning can refer to a method of training an artificial neural network when labels for training data are not given. Reinforcement learning can refer to a learning method in which an agent defined in an environment is trained to select an action or action sequence that maximizes cumulative compensation in each state.

[0628] Machine learning realized by a deep neural network (DNN) with multiple hidden layers in an artificial neural network is sometimes called deep learning, and deep learning is a part of machine learning. In the following, machine learning is used to include deep learning.

[0629] Furthermore, the above-described technical features can be applied to wireless communication of a robot.

[0630] A robot can refer to a machine that automatically processes or operates a given task using its own capabilities. In particular, a robot that has the ability to recognize its environment, make its own decisions, and take action can be called an intelligent robot.

[0631] Robots can be classified into industrial, medical, domestic, military, etc. depending on their intended use and field. Robots are equipped with actuators or motors that actuate the robot joints and perform various physical actions. Mobile robots have wheels, brakes, propellers, etc. that actuate the robots, allowing them to move on the ground or fly in the air.

[0632] Furthermore, the above-described technical features can be applied to a device that supports augmented reality.

[0633] 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 combines and presents virtual objects in the real world.

[0634] MR technology is similar to AR technology in that it displays both real and virtual objects, but it differs in that AR technology uses virtual objects to complement real objects, while MR technology uses virtual objects and real objects in an equal manner.

[0635] XR technology can be 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.

[0636] The claims and the like described in this specification may be combined in various ways. For example, the technical features of the method claims of this specification may be combined to realize an apparatus, and the technical features of the apparatus claims of this specification may be combined to realize a method. Furthermore, the technical features of the method claims of this specification and the technical features of the apparatus claims of this specification may be combined to realize an apparatus, and the technical features of the method claims of this specification and the technical features of the apparatus claims of this specification may be combined to realize a method.

Claims

1. 1. A method performed in a multi-link device (MLD) coupled to a plurality of links, including a first link, of a wireless local area network, the method comprising: A request frame including an information field for requesting all elements included in an element set designated for a second link is transmitted to a first AP (Access Point) of the multilink device via a first STA (Station) included in the multilink device; the first STA operating on the first link; receiving a response frame from the first AP via the first STA based on the request frame; the response frame including all elements included in a specified element set for the second link.

2. The method of claim 1 , wherein the request frame includes identifier information for the second link.

3. 2. The method of claim 1, wherein the element set specified for the second link includes an element related to a capability for the second link or an element related to a parameter for the second link.

4. The method of claim 1 , wherein the second link is distinct from the plurality of links.

5. transmitting a second request frame to request a change of the link to which the first STA is connected from the first link to the second link based on the response frame; receiving a second response frame based on the second request frame; and performing a procedure for changing a link to which the first STA is connected from the first link to the second link based on the second response frame.

6. The first STA is connected to a second AP of the AP multi-link device based on the procedure for changing the link to which the first STA is connected from the first link to the second link; The method of claim 5 , wherein the second AP operates on the second link.

7. The request frame includes 1-bit information for indicating that all elements included in the specified element set are requested, The method of claim 1 , wherein the one-bit information is set to a first value.

8. 2. The method of claim 1, wherein the request frame further includes an information field for requesting all elements included in an element set designated for a third link of the plurality of links.

9. The method of claim 1 , wherein the plurality of links and the second link are included within the 2.4 GHz, 5 GHz, and 6 GHz bands.

10. In a multi-link device (MLD) operating on a plurality of links including a first link of a wireless local area network (WLAN) system, a first STA (station) operating on the first link; a transceiver for transmitting and receiving radio signals; a processor coupled to the transceiver; The processor: Transmitting a request frame including an information field for requesting all elements included in an element set designated for a second link to a first AP of an AP multilink device via the first STA; the first STA operates on the first link; receiving a response frame from the first AP via the first STA based on the request frame; The response frame is configured to include all elements included in a specified element set for the second link.

11. The multi-link device of claim 10 , wherein the request frame includes identifier information for the second link.

12. 11. The multi-link device of claim 10, wherein the element set specified for the second link includes an element related to a capability for the second link or an element related to a parameter for the second link.

13. The multi-link device of claim 10 , wherein the second link is distinct from the plurality of links.

14. The processor: transmitting a second request frame to request a change of the link to which the first STA is connected from the first link to the second link based on the response frame; receiving a second response frame based on the second request frame; 14. The multi-link device of claim 13, further configured to: perform a procedure for changing a link to which the first STA is connected from the first link to the second link based on the second response frame.

15. The first STA is connected to a second AP of the AP multi-link device based on the procedure for changing the link to which the first STA is connected from the first link to the second link; The multi-link device of claim 14 , wherein the second AP operates on the second link.

16. The request frame includes 1-bit information for indicating that all elements included in the specified element set are requested, The multi-link device of claim 10 , wherein the one-bit information is set to a first value.

17. 11. The multi-link device of claim 10, wherein the request frame further includes an information field for requesting all elements included in an element set designated for a third link among the plurality of links.

18. 11. The multi-link device of claim 10, wherein the plurality of links and the second link are included within the 2.4 GHz, 5 GHz, and 6 GHz bands.

19. A computer-readable medium encoded with at least one computer program including instructions, the instructions, when executed by at least one processor, causing the at least one processor to: Transmitting a request frame including an information field for requesting all elements included in an element set designated for the second link to a first AP of the AP multilink device via a first STA (Station) operating on the first link; receiving a response frame from the first AP via the first STA based on the request frame; the response frame includes all elements included in an element set specified for the second link.

20. In devices used in wireless LAN systems, a processor; a memory coupled to the processor; The processor: A request frame including an information field for requesting all elements included in an element set designated for a second link is transmitted to a first AP of an AP multilink device via a first STA (Station) operating on the first link; receiving a response frame from the first AP via the first STA based on the request frame; The response frame is configured to include all elements included in a specified element set for the second link.

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