KR20240020661A - Method and apparatus for changing link in wireless local area network supporting enhanced multi-link single radio - Google Patents

Abstract

A method and device for changing a link in a wireless LAN supporting EMLSR are disclosed. The method of a first device includes receiving, from a second device, a first frame including first information indicating discontinuation of use of the first link on a first link among multiple links, and and performing a first communication with the second device on a second link whose use is not indicated by the first frame.

Description

Method and device for changing link in wireless LAN supporting EMLSR {METHOD AND APPARATUS FOR CHANGING LINK IN WIRELESS LOCAL AREA NETWORK SUPPORTING ENHANCED MULTI-LINK SINGLE RADIO}

This disclosure relates to wireless local area network (WLAN) communication technology, and more specifically, to link (re)establishment technology for multi-link operation of an enhanced multi-link single radio (EMLSR) device.

Recently, as the spread of mobile devices has expanded, wireless LAN (Wireless Local Area Network) technology, which can provide fast wireless communication services to mobile devices, has been receiving a lot of attention. Wireless LAN technology may be a technology that allows mobile devices such as smart phones, smart pads, laptop computers, portable multimedia players, embedded devices, etc. to wirelessly access the Internet based on wireless communication technology in a short distance.

As applications requiring higher throughput and real-time transmission arise, the IEEE 802.11be standard, an Extreme High Throughput (EHT) wireless LAN technology, is being developed. The goal of the IEEE 802.11be standard may be to support throughput rates as high as 30 Gbps. The IEEE 802.11be standard can support techniques to reduce transmission delay. In addition, the IEEE 802.11be standard provides expanded frequency bandwidth (e.g., 320 MHz bandwidth), multi-link transmission and aggregation operations, including operations using multi-bands, It may support multiple Access Point (AP) transmission operations and/or efficient retransmission operations (e.g., Hybrid Automatic Repeat Request (HARQ) operations).

However, since multi-link operation is an operation not defined in the existing wireless LAN standard, detailed operation definition may be necessary depending on the environment in which the multi-link operation is performed. In particular, devices that support enhanced multi-link single radio (EMLSR) operation (e.g., station (STA), multi-link device (MLD)) can wait for reception on multiple links. Devices that support EMLSR operation May be referred to as an EMLSR device.

If the EMLSR device starts transmitting and receiving frames on a single link, the EMLSR device can operate only on the single link. In other words, the EMLSR device cannot perform frame transmission and reception operations on another link while performing frame transmission and reception operations on a single link. Time may be required for the EMLSR device to transition transceiver between links. Therefore, methods for transmitting and receiving multi-link data that take into account the operation characteristics of the single link of the EMLSR device may be necessary. Additionally, link change methods and/or link (re)establishment methods for multi-link operation of the EMLSR device may be necessary.

Meanwhile, the technology behind the invention was written to improve understanding of the background of the invention, and may include content that is not prior art already known to those skilled in the art in the field to which this technology belongs.

The purpose of the present disclosure to solve the above problems is to provide a method and device for changing and/or (re)configuring a link for an enhanced multi-link single radio (EMLSR) device.

A method of a first device according to embodiments of the present disclosure for achieving the above object includes sending a first frame including first information indicating discontinuation of use of the first link in a first link among multiple links. Receiving from a second device, and performing a first communication with the second device on a second link of the multiple links whose use is not indicated by the first frame, and performing a first communication with the second device in the first frame. The second communication between the first device and the second device is not performed in the first link whose use is instructed to be discontinued.

The first frame may further include second information indicating a point in time when use of the first link is discontinued, and the first communication between the first device and the second device in the second link is at the point in time when use is discontinued. It may be performed from, and the first link may not be used from the point of discontinuation of use.

The first information may be TID-to-link mapping information, and there may be no TID mapped to the first link in the TID-to-link mapping information.

Performing a first communication with the second device may include receiving a data frame from the second device on the second link without receiving an initial control frame from the second device, and receiving a data frame from the second device on the second link. It may include transmitting a response frame to the data frame to the second device.

"The first device supports EMLSR operation, the first link and the second link are EMLSR links, and only one link of the EMLSR links is available due to a discontinuation instruction according to the first frame. ", the EMLSR operation of the first device may be stopped.

The first frame may be a beacon frame or an EHT action frame.

The first device may be an STA MLD, the first device may include a first STA operating on the first link and a second STA operating on the second link, and the second device may be an AP MLD may be, and the second device may include a first AP operating on the first link and a second AP operating on the second link.

A method of a first device according to embodiments of the present disclosure for achieving the above object includes sending a first frame including first information indicating discontinuation of use of the first link in a first link among multiple links. 2. Receiving from a device, and performing a listening operation on a second link and a third link of the multiple links that are not indicated to be discontinued by the first frame, and which are not in use by the first frame. Communication between the first device and the second device is not performed on the first link where interruption is indicated.

The first frame may further include second information indicating a point in time when use of the first link is discontinued, and the first link may not be used from the time point in which use of the first link is discontinued.

Prior to the point of discontinuation, the EMLSR links may include the first link, the second link, and the third link, and after the point of discontinuation, the EMLSR links may include the second link and the third link. may include, and the EMLSR links may be reestablished based on the first frame.

The first information may be TID-to-link mapping information, and there may be no TID mapped to the first link in the TID-to-link mapping information.

The method of the first device includes receiving an initial control frame from the second device on one of the second link and the third link, and after receiving the initial control frame, receiving data on the one link. It may further include receiving a frame from the second device.

The first device may be an STA MLD, and the first device may include a first STA operating on the first link, a second STA operating on the second link, and a third STA operating on the third link. It may include, the second device may be an AP MLD, and the second device may include a first AP operating on the first link, a second AP operating on the second link, and a third AP operating on the third link. It may include a third AP.

A method of a second device according to embodiments of the present disclosure for achieving the above object includes generating a first frame including first information indicating discontinuation of use of a first link among multiple links, the first frame Transmitting the first frame to a first device on one link, and performing first communication with the first device on a second link of the multiple links whose use is not indicated by the first frame. It includes, and the second communication between the first device and the second device is not performed on the first link whose use is indicated by the first frame.

Performing first communication with the first device includes, when the second device does not perform an EMLSR operation, transmitting a data frame to the first device without transmitting an initial control frame on the second link. It can be included.

Performing first communication with the first device may include, when the second device performs an EMLSR operation, transmitting an initial control frame to the first device on the second link, and After transmission, the method may include transmitting the data frame to the first device on the second link.

The first information may be TID-to-link mapping information, and there may be no TID mapped to the first link in the TID-to-link mapping information.

"The first device supports EMLSR operation, the first link and the second link are EMLSR links, and only one link of the EMLSR links is available due to a discontinuation instruction according to the first frame. ", the EMLSR operation of the first device may be stopped.

The first frame may further include second information indicating a point in time when use of the first link is discontinued, and the first link may not be used from the time point in which use of the first link is discontinued.

Prior to the outage point, the EMLSR links may include the first link, the second link, and the third link, and after the outage point, the EMLSR links may include the second link and the third link. may include, and the EMLSR links may be reestablished based on the first frame.

According to the present disclosure, an enhanced multi-link single radio (EMLSR) device can wait to receive a frame (eg, a data frame) on links corresponding to the number of antennas. When a frame is received on a first link, the EMLSR device can switch the radio chain to the first link on which the frame was received and quickly receive the frame over a plurality of spatial streams on the first link. . The operation of the EMLSR device can be changed by an access point (AP). The operation of the EMLSR device may change depending on the operation of the AP and/or STA (station). Therefore, EMLSR devices can perform communication smoothly.

Figure 1 is a conceptual diagram showing a first embodiment of a wireless LAN system.
Figure 2 is a block diagram showing a first embodiment of a communication node constituting a wireless LAN system.
Figure 3 is a conceptual diagram showing a first embodiment of multiple links established between MLDs.
Figure 4 is a flowchart showing the connection procedure of a station in a wireless LAN system.
Figure 5 is a timing diagram showing a first embodiment of an operation method of a communication node based on EDCA.
Figure 6 is a block diagram showing a first embodiment of an EMLSR device in a wireless LAN.
FIG. 7A is a timing diagram illustrating a first embodiment of a link change method for an EMLSR device in a wireless LAN supporting multiple links.
FIG. 7B is a timing diagram illustrating a second embodiment of a link change method for an EMLSR device in a wireless LAN supporting multiple links.
FIG. 8A is a timing diagram illustrating a third embodiment of a link change method for an EMLSR device in a wireless LAN supporting multiple links.
FIG. 8B is a timing diagram illustrating a fourth embodiment of a link change method for an EMLSR device in a wireless LAN supporting multiple links.
Figure 9 is a timing diagram illustrating a first embodiment of a link change method in a wireless LAN supporting multiple links.
Figure 10 is a timing diagram illustrating a fifth embodiment of a link change method for an EMLSR device in a wireless LAN supporting multiple links.
FIG. 11 is a timing diagram illustrating a sixth embodiment of a link change method for an EMLSR device in a wireless LAN supporting multiple links.
Figure 12 is a block diagram showing a first embodiment of a control field format for EMLSR configuration between AP MLD and STA MLD.

Since the present disclosure can make various changes and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit the present disclosure to specific embodiments, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present disclosure.

Terms such as first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, a first component may be referred to as a second component, and similarly, the second component may be referred to as a first component without departing from the scope of the present disclosure. The term “and/or” includes any of a plurality of related stated items or a combination of a plurality of related stated items.

In embodiments of the present disclosure, “at least one of A and B” may mean “at least one of A or B” or “at least one of combinations of one or more of A and B.” Additionally, in embodiments of the present disclosure, “one or more of A and B” may mean “one or more of A or B” or “one or more of combinations of one or more of A and B.”

When a component is said to be "connected" or "connected" to another component, it is understood that it may be directly connected to or connected to the other component, but that other components may exist in between. It should be. On the other hand, when it is mentioned that a component is “directly connected” or “directly connected” to another component, it should be understood that there are no other components in between.

The terms used in this disclosure are only used to describe specific embodiments and are not intended to limit the disclosure. Singular expressions include plural expressions unless the context clearly dictates otherwise. In the present disclosure, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the technical field to which this disclosure pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and unless clearly defined in the present disclosure, should not be interpreted in an idealized or excessively formal sense. No.

Hereinafter, preferred embodiments of the present disclosure will be described in more detail with reference to the attached drawings. In order to facilitate overall understanding in explaining the present disclosure, the same reference numerals are used for the same components in the drawings, and duplicate descriptions of the same components are omitted.

Below, a wireless communication system to which embodiments according to the present disclosure are applied will be described. The wireless communication system to which the embodiments according to the present disclosure are applied is not limited to the content described below, and the embodiments according to the present disclosure can be applied to various wireless communication systems. A wireless communication system may be referred to as a “wireless communication network.”

Figure 1 is a conceptual diagram showing a first embodiment of a wireless LAN system.

Referring to FIG. 1, a wireless LAN system may include at least one basic service set (BSS). BSS refers to a set of stations (STA1, STA2 (AP1), STA3, STA4, STA5 (AP2), STA6, STA7, STA8) that are successfully synchronized and can communicate with each other, and is not a concept referring to a specific area. . In the embodiments below, a station that performs the function of an access point may be referred to as an “access point (AP),” and a station that does not perform the function of an access point may be referred to as a “non-AP station” or “station.” It can be referred to as ".

BSS can be divided into infrastructure BSS (infrastructure BSS) and independent BSS (IBSS). Here, BSS1 and BSS2 may mean infrastructure BSS, and BSS3 may mean IBSS. BSS1 is a distribution system that connects a first station (STA1), a first access point (STA2 (AP1)) providing distribution service, and a plurality of access points (STA2 (AP1), STA5 (AP2)) It may include a distribution system (DS). In BSS1, the first access point (STA2 (AP1)) can manage the first station (STA1).

BSS2 includes a third station (STA3), a fourth station (STA4), a second access point (STA5 (AP2)) providing distribution services, and a plurality of access points (STA2 (AP1), STA5 (AP2)). It may include a connecting distribution system (DS). In BSS2, the second access point (STA5 (AP2)) can manage the third station (STA3) and the fourth station (STA4).

BSS3 may refer to an IBSS operating in ad-hoc mode. In BSS3, there may not be an access point, which is a centralized management entity. In other words, in BSS3, the stations STA6, STA7, and STA8 can be managed in a distributed manner. In BSS3, all stations (STA6, STA7, STA8) may represent mobile stations, and are not allowed to access the distribution system (DS), so they form a self-contained network.

The access points (STA2 (AP1), STA5 (AP2)) may provide access to the distributed system (DS) via a wireless medium for the stations (STA1, STA3, STA4) associated with them. Communication between stations (STA1, STA3, STA4) in BSS1 or BSS2 is generally accomplished through access points (STA2 (AP1), STA5 (AP2)), but when a direct link is established, the stations ( Direct communication between STA1, STA3, and STA4) is possible.

Multiple infrastructure BSSs may be interconnected through a distribution system (DS). A plurality of BSSs connected through a distribution system (DS) are called an extended service set (ESS). Communication nodes (STA1, STA2 (AP1), STA3, STA4, STA5 (AP2)) included in the ESS can communicate with each other, and any station (STA1, STA3, STA4) within the same ESS can communicate without interruption. You can move from one BSS to another BSS.

A distribution system (DS) is a mechanism for one access point to communicate with another access point, whereby the access point transmits frames for stations associated with the BSS it manages or moves to another BSS. Frames can be transmitted for any station. Additionally, the access point can transmit and receive frames to and from external networks such as wired networks. This distribution system (DS) does not necessarily have to be a network, and there are no restrictions on its form as long as it can provide a certain distribution service specified in the IEEE 802.11 standard. For example, the distribution system may be a wireless network such as a mesh network, or it may be a physical structure that connects access points to each other. Communication nodes (STA1, STA2 (AP1), STA3, STA4, STA5 (AP2), STA6, STA7, STA8) included in the wireless LAN system may be configured as follows.

Figure 2 is a block diagram showing a first embodiment of a communication node constituting a wireless LAN system.

Referring to FIG. 2, the communication node 200 may include at least one processor 210, a memory 220, and a transmitting and receiving device 230 that is connected to a network and performs communication. The transmitting and receiving device 230 may be referred to as a transceiver, a radio frequency (RF) unit, an RF module, etc. Additionally, the communication node 200 may further include an input interface device 240, an output interface device 250, a storage device 260, etc. Each component included in the communication node 200 is connected by a bus 270 and can communicate with each other.

However, each component included in the communication node 200 may be connected through an individual interface or individual bus centered on the processor 210, rather than the common bus 270. For example, the processor 210 may be connected to at least one of the memory 220, the transmission/reception device 230, the input interface device 240, the output interface device 250, and the storage device 260 through a dedicated interface. .

The processor 210 may execute a program command stored in at least one of the memory 220 and the storage device 260. The processor 210 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present disclosure are performed. Each of the memory 220 and the storage device 260 may be comprised of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 220 may be comprised of at least one of read only memory (ROM) and random access memory (RAM).

FIG. 3 is a conceptual diagram illustrating a first embodiment of a multi-link established between multi-link devices (MLDs).

Referring to FIG. 3, the MLD may have one medium access control (MAC) address. In embodiments, MLD may refer to AP MLD and/or non-AP MLD. The MLD's MAC address can be used in the multi-link setup procedure between non-AP MLD and AP MLD. The MAC address of the AP MLD may be different from the MAC address of the non-AP MLD. Access point(s) associated with an AP MLD may have different MAC addresses, and station(s) associated with a non-AP MLD may have different MAC addresses. Access points within the AP MLD with different MAC addresses can be in charge of each link and can function as independent access points (APs).

Stations in a non-AP MLD with different MAC addresses can be in charge of each link and can perform the role of an independent station (STA). Non-AP MLD may also be referred to as STA MLD. MLD can support simultaneous transmit and receive (STR) operation. In this case, the MLD can perform a transmission operation on link 1 and a reception operation on link 2. An MLD that supports STR operation may be referred to as STR MLD (eg, STR AP MLD, STR non-AP MLD). In embodiments, a link may mean a channel or a band. A device that does not support STR operation may be referred to as a non-STR (NSTR) AP MLD or NSTR non-AP MLD (or NSTR STA MLD). AP in AP MLD may mean an AP linked to AP MLD. STA in STA MLD may mean an STA linked to STA MLD.

MLD can transmit and receive frames on multiple links by using a discontinuous bandwidth expansion method (e.g., 80MHz + 80MHz). Multi-link operation may include multi-band transmission. The AP MLD may include multiple access points, and the multiple access points may operate on different links. Each of the plurality of access points may perform the function(s) of the lower MAC layer. Each of the plurality of access points may be referred to as a “communication node” or “sub-entity.” A communication node (eg, an access point) may operate under the control of a higher layer (or the processor 210 shown in FIG. 2). A non-AP MLD may include multiple stations, and the multiple stations may operate on different links. Each of the plurality of stations may be referred to as a “communication node” or “sub-entity.” A communication node (eg, station) may operate under the control of a higher layer (or the processor 210 shown in FIG. 2).

MLD can perform communication in multi-band. For example, MLD can communicate using a 40MHz bandwidth in the 2.4GHz band depending on the channel expansion method (e.g., bandwidth expansion method), and communicate using a 160MHz bandwidth in the 5GHz band depending on the channel expansion method. can be performed. MLD can perform communication using a 160MHz bandwidth in the 5GHz band, and can perform communication using a 160MHz bandwidth in the 6GHz band. One frequency band (e.g., one channel) used by MLD can be defined as one link. Alternatively, multiple links may be established in one frequency band used by MLD. For example, MLD can establish one link in the 2.4GHz band and two links in the 6GHz band. Each link may be referred to as a first link, a second link, a third link, etc. Alternatively, each link may be referred to as link 1, link 2, link 3, etc. The link number may be set by the access point, and an ID (identifier) may be assigned to each link.

The MLD (e.g., AP MLD and/or non-AP MLD) may establish multiple links by performing an access procedure and/or negotiation procedure for multi-link operation. In this case, the number of links and/or the link to be used among multiple links may be set. A non-AP MLD (eg, station) can check band information capable of communicating with the AP MLD. In the negotiation procedure for multi-link operation between the non-AP MLD and the AP MLD, the non-AP MLD can configure one or more links among the links supported by the AP MLD to be used for the multi-link operation. A station that does not support multi-link operation (eg, IEEE 802.11a/b/g/n/ac/ax station) may be connected to one or more links among the multiple links supported by AP MLD.

Each of the AP MLD and STA MLD may have an MLD MAC address, and each AP and STA operating on each link may have a MAC address. The MLD MAC address of the AP MLD may be referred to as the AP MLD MAC address, and the MLD MAC address of the STA MLD may be referred to as the STA MLD MAC address. The MAC address of the AP may be referred to as the AP MAC address, and the MAC address of the STA may be referred to as the STA MAC address. The AP MLD MAC address and STA MLD MAC address can be used in the multi-link negotiation procedure. AP addresses and STA addresses may be exchanged and/or set in a multi-link negotiation procedure.

Once the multi-link negotiation procedure is completed, the AP MLD can create an address table and manage and/or update the address table. One AP MLD MAC address may be mapped to one or more AP MAC addresses, and the corresponding mapping information may be included in an address table. One STA MLD MAC address may be mapped to one or more STA MAC addresses, and the corresponding mapping information may be included in the address table. AP MLD can check address information based on the address table. For example, when an STA MLD MAC address is received, the AP MLD can check one or more STA MAC addresses mapped to the STA MLD MAC address based on the address table.

Additionally, the STA MLD can manage and/or update the address table. The address table may include “mapping information between AP MLD MAC address and AP MAC address(es)” and/or “mapping information between STA MLD MAC address and STA MAC address(es).” The AP MLD can receive a packet from the network, check the address of the STA MLD included in the packet, check the link(s) supported by the STA MLD, and identify the link(s) in the address table. You can check your STA(s). The AP MLD can set the STA MAC address(es) of the confirmed STA(s) as the receiver address, and can generate and transmit frame(s) including the receiver address.

Meanwhile, the connection procedure in a wireless LAN system can be performed as follows.

Figure 4 is a flowchart showing the station connection procedure in a wireless LAN system.

Referring to FIG. 4, the connection procedure of a station (STA) in an infrastructure BSS largely includes a step of detecting an access point (AP) (probe step), an authentication step with the detected access point (AP) (authentication step), and authentication. It can be divided into an association step with the access point (AP) that performed the procedure. A station (STA) may be an STA MLD or an STA associated with an STA MLD, and an access point (AP) may be an AP MLD or an AP associated with an AP MLD.

The station (STA) may first detect neighboring access points (APs) using a passive scanning method or an active scanning method. When using a passive scanning method, a station (STA) can detect neighboring access points (APs) by overhearing beacons transmitted by the access points (APs). When using the active scanning method, the station (STA) can transmit a probe request frame and receive a probe response frame, which is a response to the probe request frame, from access points (APs). By doing so, neighboring access points (APs) can be detected.

When neighboring access points (APs) are detected, the station (STA) may perform an authentication step with the detected access point (AP). In this case, the station (STA) may perform an authentication step with a plurality of access points (APs). Authentication algorithms according to the IEEE 802.11 standard can be divided into an open system algorithm that exchanges two authentication frames, a shared key algorithm that exchanges four authentication frames, etc.

The station (STA) can transmit an authentication request frame based on the authentication algorithm according to the IEEE 802.11 standard, and receives an authentication response frame, which is a response to the authentication request frame, from the access point (AP). By receiving, authentication with the access point (AP) can be completed.

When authentication with the access point (AP) is completed, the station (STA) can perform the connection step with the access point (AP). In this case, the station (STA) can select one access point (AP) among the access points (APs) that performed the authentication step with itself, and perform the connection step with the selected access point (AP). In other words, the station (STA) may transmit an association request frame to the selected access point (AP), and an association response frame that is a response to the association request frame from the selected access point (AP) By receiving, connection with the selected access point (AP) can be completed.

Meanwhile, communication nodes (e.g., access points, stations, etc.) belonging to the wireless LAN system use point coordination function (PCF), hybrid coordination function (HCF), HCF controlled channel access (HCCA), distributed coordination function (DCF), Frame transmission and reception operations can be performed based on enhanced distributed channel access (EDCA), etc.

In a wireless LAN system, frames can be classified into management frames, control frames, and data frames. Management frames include association request frame, association response frame, reassociation request frame, reassociation response frame, probe request frame, probe response frame, beacon frame, and connection. It may include a disassociation frame, authentication frame, deauthentication frame, action frame, etc.

Control frames include ACK (acknowledgement) frame, BAR (block ACK request) frame, BA (block ACK) frame, PS (power saving)-Poll frame, RTS (request to send) frame, CTS (clear to send) frame, etc. It can be included. Data frames can be classified into quality of service (QoS) data frames and non-QoS (non-QoS) data frames. A QoS data frame may indicate a data frame requiring transmission according to QoS, and a non-QoS data frame may indicate a data frame not requiring transmission according to QoS. A QoS data frame may include a QoS Null frame, and a QoS Null frame may not include a payload.

Meanwhile, in a wireless LAN system, communication nodes (eg, access points, stations) may operate based on EDCA.

Figure 5 is a timing diagram showing a first embodiment of an operation method of a communication node based on EDCA.

Referring to FIG. 5, a communication node that wishes to transmit a control frame (or management frame) monitors the channel status during a preset interval (e.g., short interframe space (SIFS), PCF IFS (PIFS)). An operation (e.g., carrier sensing operation) can be performed, and if the channel state is determined to be idle during a preset period (e.g., SIFS, PIFS), a control frame ( Alternatively, a management frame) may be transmitted. For example, if the channel state is determined to be idle during SIFS, the communication node may transmit an ACK frame, BA frame, CTS frame, etc. Additionally, the communication node may transmit a beacon frame, etc. when the channel state is determined to be idle during PIFS. On the other hand, if the channel state is determined to be busy during a preset period (eg, SIFS, PIFS), the communication node may not transmit a control frame (or management frame). Here, the carrier sensing operation may indicate a clear channel assessment (CCA) operation.

A communication node wishing to transmit a non-QoS data frame may perform a monitoring operation (e.g., carrier sensing operation) of the channel state during DIFS (DCF IFS), and if the channel state is determined to be idle during DIFS, A random backoff procedure can be performed. For example, a communication node may select a backoff value (e.g., a backoff counter) within a contention window according to a random backoff procedure, and an interval corresponding to the selected backoff value (hereinafter referred to as "backoff counter"). During the “off period”), a channel state monitoring operation (for example, a carrier sensing operation) may be performed. A communication node may transmit a non-QoS data frame when the channel state is determined to be idle during the backoff period.

A communication node wishing to transmit a QoS data frame may perform a channel state monitoring operation (e.g., carrier sensing operation) during AIFS (arbitration IFS), and may perform a random back signal if the channel state is determined to be idle during AIFS. Off procedures can be performed. AIFS may be set according to the access category (AC) of the data unit (eg, protocol data unit (PDU)) included in the QoS data frame. The AC of the data unit may be as shown in Table 1 below.

AC_BK can indicate background data, AC_BE can indicate data transmitted in the best effort method, AC_VI can indicate video data, and AC_VO can indicate voice ( voice) can indicate data. For example, the length of AIFS for QoS data frames corresponding to each of AC_VO and AC_VI may be set equal to the length of DIFS. The length of AIFS for the QoS data frame corresponding to each of AC_BE and AC_BK may be set longer than the length of DIFS. Here, the length of the AIFS for the QoS data frame corresponding to AC_BK may be set longer than the length of the AIFS for the QoS data frame corresponding to AC_BE.

In a random backoff procedure, a communication node may select a backoff value (e.g., backoff counter) within a contention window according to the AC of the QoS data frame. The competition window according to AC may be as shown in Table 2 below. CW _min may indicate the minimum value of the competition window, and CW _max may indicate the maximum value of the competition window, and each of the minimum and maximum values of the competition window may be expressed as the number of slots.

The communication node may perform a channel state monitoring operation (eg, a carrier sensing operation) during the backoff period, and may transmit a QoS data frame when the channel state is determined to be in an idle state during the backoff period.

Next, methods for transmitting and receiving data in a wireless LAN system will be explained. Even when a method (e.g., transmission or reception of a signal) performed in a first communication node among communication nodes is described, the corresponding second communication node is described as a method (e.g., transmitting or receiving a signal) corresponding to the method performed in the first communication node. For example, reception or transmission of a signal) can be performed. In other words, when the operation of the STA is described, the corresponding AP can perform the operation corresponding to the operation of the STA. Conversely, when the operation of the AP is described, the corresponding STA can perform the operation corresponding to the operation of the AP. In an embodiment, the operation of the STA may be interpreted as the operation of the STA MLD, the operation of the STA MLD may be interpreted as the operation of the STA, the operation of the AP may be interpreted as the operation of the AP MLD, and the operation of the AP MLD can be interpreted as the operation of the AP.

Figure 6 is a block diagram showing a first embodiment of an enhanced multi-link single radio (EMLSR) device in a wireless LAN.

Referring to FIG. 6, the EMLSR device 600 may be an MLSR operation and/or an MLD that supports the EMLSR operation. EMLSR device 600 may be referred to as an MLSR device. An EMLSR STA (or MLSR STA) may be an STA that supports MLSR operations and/or EMLSR operations, and an EMLSR AP (or MLSR AP) may be an AP that supports MLSR operations and/or EMLSR operations. MLSR operation may mean MLSR mode, and EMLSR operation may mean EMLSR mode. The EMLSR device 600 includes antennas 610-1 and 610-2, EMLSR control message detection blocks 620-1 and 620-2, a spatial stream processing block 630, a modulation and demodulation block 640, It may include a wireless LAN modem 650 and/or an upper layer block 660. In an embodiment the spatial stream may be referred to as SS.

EMLSR device 600 may include a plurality of antennas 610-1 and 610-2. The first antenna 610-1 may be used for a sensing operation and/or a reception operation of a signal in the first link. The second antenna 610-2 may be used for sensing and/or receiving operations of signals in the second link. The frequency at which the first link operates may be different from the frequency at which the second link operates. The sensing operation and/or receiving operation performed by the first antenna and/or the second antenna may be a listening operation. In order to simultaneously receive spatial stream signals, the first antenna 610-1 and the second antenna 610-2 perform a sensing operation and/or a reception operation of signals in one of the first link and the second link. can do.

Among the plurality of antennas 610-1 and 610-2 included in the EMLSR device 600, one antenna may be a primary antenna, and the remaining antenna(s) may be secondary antenna(s). It can be. The primary antenna and secondary antenna can be set in advance. Alternatively, the primary antenna and secondary antenna may be set in a negotiation procedure between the EMLSR device 600 and another device (e.g., an AP or an AP MLD that supports EMLSR operation). The antenna performing the listening operation on the link with a low number (e.g., low index) may be set as the primary antenna, and the remaining antenna(s) may be set as the secondary antenna(s).

The first EMLSR control frame detection block 620-1 may be connected to or linked to the first antenna 610-1, and the second EMLSR control frame detection block 620-2 may be connected to the second antenna 610-2. Can be connected or linked to. Electromagnetic waves (eg, signals) detected by the antennas 610-1 and 610-2 may be input to the EMLSR control frame detection blocks 620-1 and 620-2. The EMLSR control frame detection blocks 620-1 and 620-2 may determine whether an electromagnetic wave (eg, signal) is a specific control frame (eg, an initial control frame). The EMLSR control frame detection blocks 620-1 and 620-2 can support only predefined modulation and coding schemes (MCS) and can only check the format of predefined control frames. The format of a predefined control frame (eg, a specific control frame, an initial control frame) may be a request to send (RTS) frame and/or a multi-user (MU)-RTS frame.

When a specific control frame is detected in the EMLSR control frame detection blocks 620-1 and 620-2, the EMLSR device 600 simultaneously detects as many spatial streams (e.g., the number of antennas) as the EMLSR device 600 supports. A reception operation of receiving data in multiple streams may be performed using multiple spatial streams. In order to perform a reception operation for receiving multiple spatial streams simultaneously, a clear to send (CTS) frame is transmitted after a short inter-frame space (SIFS) from the time of detection of a specific control frame in the first link to the first antenna 610- It can be transmitted through 1), and the second antenna 610-2, which was operating on the second link where a specific control frame was not detected, can switch to the first link and operate. In other words, the RX radio chain can be switched and operate on the first link. A receiving radio chain may refer to a radio chain in this disclosure. Additionally, radio chain may mean a reception radio chain or a reception chain in this disclosure. Radio chain may refer to an RF (radio frequency) chain. Switching of the operating link of the second antenna 610-2 (e.g., switching of the radio chain) may begin after detection of a specific control frame in the first link, and transmit a CTS signal after the SIFS time and then after the SIFS time. It can be completed up to. Multiple spatial streams (eg, two spatial streams) may then be received through a plurality of antennas 610-1 and 610-2. “The operation of receiving a MU-RTS trigger frame and the operation of switching the radio chain to receive multiple spatial streams” may be an EMLSR operation.

“A signal is received from one of the plurality of antennas 610-1 and 610-2, and the received signal is a specific control frame detected by the EMLSR control frame detection blocks 620-1 and 620-2. If not, the received signal may be transmitted to the modulation/demodulation block 640 without going through the spatial stream processing block 630. The antenna that performs the above operation (eg, the operation of transmitting the received signal to the modulation/demodulation block 640) may be a primary antenna.

“When a specific control frame is detected in the EMLSR control frame detection blocks 620-1 and 620-2, and a reception procedure for multiple spatial streams is performed,” the spatial stream processing block 630 uses a plurality of antennas 610. A rearrangement operation of signals (eg, symbols) received from -1, 610-2) may be performed. When a space time code is used, a single symbol can be generated into multiple symbols by a coding operation, and the multiple symbols can be transmitted. The space-time code may be an Alamouti code. The spatial stream processing block 630 may perform an operation to restore symbols that are duplicated in a decoding procedure into a single symbol.

The output symbols of the spatial stream processing block 630 may be input to the modulation/demodulation block 640. The modulation/demodulation block 640 may generate bits by performing a demodulation operation on symbols. The modulation/decoding block 640 may perform a channel coding operation and/or a channel decoding operation. The output bits of the modulation/demodulation block 640 may be transmitted to the wireless LAN modem 650. The wireless LAN modem 650 can perform medium access control (MAC) operations defined in the IEEE 802.11 standard. The output of the wireless LAN modem 650 may be delivered to the upper layer block 660. The upper layer block 660 can perform upper layer operations defined in the IEEE 802.11 standard. A series of operations performed after a specific control frame is detected in the EMLSR control frame detection block may be operations performed during the EMLSR operation. In the EMLSR device 600, the transmission operation may be performed in the reverse order of the above-described reception operation. The above-described antenna may be an RF chain (radio frequency chain), which is a transmitting and receiving block including an antenna. The RF chain may be a hardware or/and logical structure that includes both a Tx chain (Transmit chain) and an Rx chain (Receive chain).

Meanwhile, EMLSR device may mean EMLSR MLD, EMLSR STA MLD, EMLSR AP MLD, EMLSR STA, and/or EMLSR AP. The operating state of the EMLSR device can be classified into a listening operating state and an EMLSR operating state. Alternatively, the operational state of an EMLSR device can be classified into a listening operational state, an EMLSR operational state, and a blindness state. In the listening operation state, the EMLSR STA may perform a reception operation for a frame (eg, an initial control frame) on EMLSR links. In the EMLSR operation state, the EMLSR STA can perform frame transmission and reception operations on a single link. A single link may be one of EMLSR links. The EMLSR operating state may mean a normal state, a normal operating state, a normal transmitting state, a normal receiving state, and/or a normal transmitting/receiving state. A section in a blind state may be referred to as a blind section. In the present disclosure, the transmission time may mean a transmission start time and/or a transmission end time, and the reception time may mean a reception start time and/or a reception end time.

FIG. 7A is a timing diagram illustrating a first embodiment of a link change method for an EMLSR device in a wireless LAN supporting multiple links.

Referring to FIG. 7A, STA MLD 1 may include STA 1-1 operating on a first link and STA 1-2 operating on a second link. The operation of STA MLD 1 in the first link may be interpreted as the operation of STA 1-1, and the operation of STA MLD 1 in the second link may be interpreted as the operation of STA 1-2. STA MLD 1 can perform EMLSR operation on the first link and the second link. In other words, STA MLD 1 may be an EMLSR device (eg, EMLSR STA MLD or EMLSR non-AP MLD). AP MLD 1 may include AP 1-1 operating on the first link and AP 1-2 operating on the second link. The operation of AP MLD 1 in the first link can be interpreted as the operation of AP 1-1, and the operation of AP MLD 1 in the second link can be interpreted as the operation of AP 1-2.

The AP MLD (e.g., AP 1-1) may transmit a frame containing link recommendation information to the STA MLD (e.g., STA 1-1). A frame containing link recommendation information may be a link recommendation EHT action frame or a beacon frame. A frame containing link recommendation information (eg, a link recommendation EHT action frame or a beacon frame) may be referred to as a link recommendation frame. Link recommendation information may indicate which link to use. AP MLD can transmit link advisory frames using unicast or broadcast methods. The link advisory frame may include at least one of a link bitmap, a partial association identifier (AID) bitmap, or an AID bitmap. A link bitmap can be associated with a partial AID bitmap or a bit position in an AID bitmap. An association between a link bitmap and a partial AID bitmap (e.g., a bit position in the partial AID bitmap) may indicate a link. Alternatively, an association between a link bitmap and an AID bitmap (e.g., a bit position in the AID bitmap) may indicate a link. The link bitmap may be a traffic indication list field for each link included in the multi-link traffic indication element. The link recommendation frame may include information indicating the link to be used for uplink and/or the link to be used for downlink.

For example, AP MLD 1 may transmit a link advisory frame to STA MLD 1. STA MLD 1 can receive a link advisory frame from AP MLD 1. The link recommendation frame of AP MLD 1 may recommend use of the second link. In this case, STA MLD 1 may perform communication using the second link indicated by the link recommendation frame. In other words, if the link advisory frame of AP MLD 1 indicates the second link, STA 1-2 may perform communication on the second link, and STA 1-1 may not perform communication on the first link. there is.

STA MLD 1 (e.g., EMLSR STA MLD) may interpret the link advisory frame of AP MLD 1 as a suspension of EMLSR operation or a re-establishment of EMLSR operation. STA MLD 1 may not operate (e.g., transition) into a listening operation state in the first link and may perform normal transmission and reception operations in the second link. In other words, STA MLD 1 can stop EMLSR operation. The link advisory frame transmitted from AP MLD 1 to STA MLD 1 may be a frame that explicitly or implicitly indicates suspension of EMLSR operation. In the downlink communication procedure between AP MLD 1 and STA MLD 1, AP MLD 1 sends a downlink frame (e.g., a downlink frame) on the second link without transmitting an initial control frame (e.g., MU-RTS trigger frame or BSRP trigger frame) , a data frame, a physical layer protocol data unit (PPDU), a medium access control (MAC) layer protocol data unit (MPDU), and an aggregated MPDU (A-MPDU) can be transmitted to STA MLD 1. In other words, if it is confirmed that STA MLD 1 does not perform the EMLSR operation, AP MLD 1 may transmit a downlink frame to STA MLD 1 on the second link without transmitting an initial control frame. STA MLD 1 can receive the downlink frame of AP MLD 1 without EMLSR operation.

Before AP MLD 1 transmits a link advisory frame to STA MLD 1, a preliminary operation to change EMLSR operation may be performed. Alternatively, after AP MLD 1 transmits the link advisory frame to STA MLD 1, a post-operation to change the EMLSR operation may be performed. For example, AP MLD 1 and STA MLD 1 perform EMLSR operations before or after transmission of a link advisory frame by exchanging EHT action frames (e.g., enhanced multi-link (EML) operating mode notification (OMN) frames). You can change it. A change in EMLSR operation may mean “performing the EMLSR operation → stopping the EMLSR operation.” Alternatively, a change in EMLSR operation may mean a change (e.g., reset) of the EMLSR link.

For example, AP MLD 1 may direct the use of one link (e.g., the second link) of STA MLD 1's EMLSR links (e.g., the first link and the second link). The use of one link may be indicated by a link advisory frame in AP MLD 1. Before transmitting the link advisory frame, AP MLD 1 may indicate suspension of EMLSR operation by transmitting an EML OMN frame to STA MLD 1. Alternatively, after receiving the link advisory frame, STA MLD 1 may indicate suspension of EMLSR operation by transmitting an EML OMN frame to AP MLD 1. Alternatively, after transmission of the link advisory frame, AP MLD 1 may indicate suspension of EMLSR operation by transmitting an EML OMN frame to STA MLD 1. The EML OMN frame of AP MLD 1 and/or STA MLD 1 may request suspension of EMLSR operation.

Alternatively, after receiving AP MLD 1's link recommendation frame, STA MLD 1 may not stop EMLSR operation on the second link. AP MLD 1 may transmit an initial control frame to STA MLD 1 for transmission of a downlink frame. Since the use of one of STA MLD 1's EMLSR links is indicated, AP MLD 1 can transmit the initial control frame to STA MLD 1 without considering EMLSR padding delay and/or EMLSR transition delay. In other words, the EMLSR padding delay and/or EMLSR transition delay may be considered or set to zero. The EMLSR padding delay or/and the EMLSR transition delay of STA MLD 1 may be considered or set to 0, and STA MLD 1 may be set to "transition operation from listening operation to normal transmit/receive operation" or "transition operation from normal transmit/receive operation to listen operation" The “action” can be performed without delay.

In the above embodiment, the EMLSR operation can be interpreted as an enhanced multi-link multi radio (EMLMR) operation. For example, an EMLSR link may be an EMLMR link, and STA MLD 1 may perform an EMLMR operation. In other words, STA MLD 1 may be EMLMR STA MLD. EMLSR padding delay and EMLSR transition delay can be interpreted as EMLMR padding delay and EMLMR transition delay, respectively.

FIG. 7B is a timing diagram illustrating a second embodiment of a link change method for an EMLSR device in a wireless LAN supporting multiple links.

Referring to FIG. 7B, STA MLD 1 may include STA 1-1 operating on the first link, STA 1-2 operating on the second link, and STA 1-3 operating on the third link. The operation of STA MLD 1 in the first link may be interpreted as the operation of STA 1-1, the operation of STA MLD 1 in the second link may be interpreted as the operation of STA 1-2, and the operation of STA MLD in the third link may be interpreted as the operation of STA 1-1. The operation of 1 can be interpreted as the operation of STA 1-3. STA MLD 1 can perform EMLSR operations on the first link, second link, and third link. In other words, STA MLD 1 may be an EMLSR device (eg, EMLSR STA MLD or EMLSR non-AP MLD). AP MLD 1 may include AP 1-1 operating on the first link, AP 1-2 operating on the second link, and AP 1-3 operating on the third link. The operation of AP MLD 1 in the first link can be interpreted as the operation of AP 1-1, the operation of AP MLD 1 in the second link can be interpreted as the operation of AP 1-2, and the operation of AP MLD in the third link The operation of 1 can be interpreted as the operation of AP 1-3.

The AP MLD (eg, AP 1-1) may transmit a link advisory frame to the STA MLD (eg, STA 1-1). Link recommendation information may indicate which link to use. AP MLD can transmit link advisory frames using unicast or broadcast methods. The link advisory frame may include at least one of a link bitmap, a partial AID bitmap, or an AID bitmap. A link bitmap can be associated with a partial AID bitmap or a bit position in an AID bitmap. An association between a link bitmap and a partial AID bitmap (e.g., a bit position in the partial AID bitmap) may indicate a link. Alternatively, an association between a link bitmap and an AID bitmap (e.g., a bit position in the AID bitmap) may indicate a link. The link bitmap may be a traffic indication list field for each link included in the multi-link traffic indication element. The link recommendation frame may include information indicating the link to be used for uplink and/or the link to be used for downlink.

For example, AP MLD 1 may transmit a link advisory frame to STA MLD 1. STA MLD 1 can receive a link advisory frame from AP MLD 1. The link recommendation frame of AP MLD 1 may recommend the use of the second link and the third link. In this case, STA MLD 1 can perform communication using the second link and third link indicated by the link recommendation frame. In other words, if the link recommendation frame of AP MLD 1 indicates the second link and the third link, STA 1-2 can perform communication on the second link, and STA 1-3 can communicate on the third link. may be performed, and STA 1-1 may not be able to perform communication on the first link.

STA MLD 1 (e.g., EMLSR STA MLD) may interpret the link advisory frame of AP MLD 1 as a suspension of EMLSR operation or re-establishment of EMLSR operation. STA MLD 1 can perform an EMLSR operation on the second link and the third link without performing a listening operation on the first link. STA MLD 1 may not use the first link. In other words, STA MLD 1 may perform listening operations on the second link and the third link to receive the downlink frame of AP MLD 1. The link advisory frame transmitted from AP MLD 1 to STA MLD 1 may be a frame that explicitly or implicitly indicates re-establishment of the EMLSR operation. “If a link advisory frame (e.g., a link advisory frame indicating re-establishment of EMLSR operation) is received, and the link advisory frame indicates a second link and a third link,” STA MLD 1 re-establishes the EMLSR links can do. For example, STA MLD 1 may change the EMLSR links from “first link, second link, and third link” to “second link and third link.”

In the downlink communication procedure between AP MLD 1 and STA MLD 1, AP MLD 1 transmits an initial control frame (e.g., MU-RTS trigger frame or BSRP trigger frame) on the second or third link and then sends the downlink Frames (e.g., data frames, PPDUs, MPDUs, A-MPDUs) may be transmitted. If STA MLD 1 is confirmed to be performing the EMLSR operation, AP MLD 1 may transmit a downlink frame after transmitting the initial control frame on the second link or the third link. STA MLD 1 may perform an EMLSR operation on the second link and/or a third link, and may receive a downlink frame according to the EMLSR operation.

Before AP MLD 1 transmits a link advisory frame to STA MLD 1, a preliminary operation to change EMLSR operation may be performed. Alternatively, after AP MLD 1 transmits the link advisory frame to STA MLD 1, a post-operation to change the EMLSR operation may be performed. For example, AP MLD 1 and STA MLD 1 can change EMLSR operation before or after transmission of a link advisory frame by exchanging EHT action frames (e.g., EML OMN frames).

For example, AP MLD 1 connects two of the EMLSR links (e.g., the first link, the second link, and the third link) of STA MLD 1 (e.g., the second link and the third link). ) can be used. The use of the two links may be indicated by a link advisory frame in AP MLD 1. Before transmitting the link advisory frame, AP MLD 1 may indicate a change in the link on which the EMLSR operation is performed by transmitting an EML OMN frame to STA MLD 1. Alternatively, after receiving the link advisory frame, STA MLD 1 may indicate a change in the link on which the EMLSR operation is performed by transmitting an EML OMN frame to AP MLD 1. Alternatively, after transmission of the link recommendation frame, AP MLD 1 may indicate a change in the link on which the EMLSR operation is performed by transmitting an EML OMN frame to STA MLD 1. The EML OMN frame of AP MLD 1 and/or STA MLD 1 may indicate a change in the link on which the EMLSR operation is performed. A change in a link may mean a re-establishment of the link.

If the link recommended by AP MLD 1 includes one link on which the EMLSR operation of STA MLD 1 is performed, the EMLSR operation may be stopped implicitly. Alternatively, EMLSR operation may be interrupted by the exchange procedure of EML OMN frames described above. If the link recommended by AP MLD 1 includes two or more links on which the EMLSR operation of STA MLD 1 is performed, the EMLSR operation may not be interrupted. In other words, the EMLSR operation can be performed on two or more links recommended by AP MLD 1.

In the above embodiment, the EMLSR operation can be interpreted as an enhanced multi-link multi radio (EMLMR) operation. For example, an EMLSR link may be an EMLMR link, and STA MLD 1 may perform an EMLMR operation. In other words, STA MLD 1 may be EMLMR STA MLD. EMLSR padding delay and EMLSR transition delay can be interpreted as EMLMR padding delay and EMLMR transition delay, respectively.

FIG. 8A is a timing diagram illustrating a third embodiment of a link change method for an EMLSR device in a wireless LAN supporting multiple links.

Referring to FIG. 8A, STA MLD 1 may include STA 1-1 operating on a first link and STA 1-2 operating on a second link. The operation of STA MLD 1 in the first link may be interpreted as the operation of STA 1-1, and the operation of STA MLD 1 in the second link may be interpreted as the operation of STA 1-2. STA MLD 1 can perform EMLSR operation on the first link and the second link. In other words, STA MLD 1 may be an EMLSR device (eg, EMLSR STA MLD or EMLSR non-AP MLD). AP MLD 1 may include AP 1-1 operating on the first link and AP 1-2 operating on the second link. The operation of AP MLD 1 in the first link can be interpreted as the operation of AP 1-1, and the operation of AP MLD 1 in the second link can be interpreted as the operation of AP 1-2.

AP MLD 1 (e.g., AP 1-1) sends a frame (e.g., a beacon frame or an action frame (e.g., an EHT action frame)) containing traffic identifier (TID)-to-link mapping information. It may be transmitted to STA MLD 1 (e.g., STA 1-1). Beacon frames may be transmitted in a broadcast manner, and EHT action frames may be transmitted in a unicast manner. TID-to-link mapping information transmitted from AP MLD 1 to STA MLD 1 may indicate discontinuation of link use. For example, if a specific link is not mapped to any TID in the TID-to-link mapping information, the TID-to-link mapping information may indicate discontinuation of use of the specific link. Discontinuation of use may mean a moratorium on use.

“A specific link is not mapped to any TID in the TID-to-link mapping information” means “There is no TID mapped to a specific link in the TID-to-link mapping information” or “TID-to-link mapping It may mean “the information does not include mapping information between a specific link and TID.” If the use of a specific link is stopped, all transmission and reception operations may not be performed on the specific link. Conversely, if a specific link is mapped to at least one TID in the TID-to-link mapping information, the TID-to-link mapping information may indicate that the specific link is available.

For example, AP MLD 1 may transmit a beacon frame containing TID-to-link mapping information to STA MLD 1. A beacon frame (eg, TID-to-link mapping information) transmitted by AP MLD 1 may indicate discontinuation of use of the first link. The beacon frame of AP MLD 1 may include information on the time of discontinuation of use of the first link. A beacon frame indicating discontinuation of use of the first link may be referred to as link discontinuation information (eg, link discontinuation frame). The discontinuation point may be an offset from the reception of the link discontinuation frame to the point in time when the link is discontinued.

STA MLD 1 may receive a beacon frame (e.g., a link disablement frame) from AP MLD 1, and information elements included in the beacon frame (e.g., TID-to-link mapping information and/or enable Information at the time of interruption) can be checked. STA MLD 1 can confirm that use of the first link is discontinued. Additionally, STA MLD 1 can confirm when the first link is discontinued. STA MLD 1 may perform communication using the second link after the first link ceases use. In other words, after the point of discontinuation of use of the first link, STA 1-2 may be able to perform communication on the second link, and STA 1-1 may not be able to perform communication on the first link.

STA MLD 1 (e.g., EMLSR STA MLD) may interpret AP MLD 1's instruction to stop using the link as stopping EMLSR operation or resetting EMLSR operation. After the point of discontinuation of use of the first link, STA MLD 1 may not operate (e.g., transition) to a listening operation state on the first link and may perform normal transmission and reception operations on the second link. In other words, STA MLD 1 may stop EMLSR operation after the first link ceases use. If only one of the EMLSR links is available due to a link stop use instruction from AP MLD 1, STA MLD 1 may stop EMLSR operation. AP MLD 1's link discontinuation instruction may implicitly indicate discontinuation of EMLSR operation. In the downlink communication procedure between AP MLD 1 and STA MLD 1, AP MLD 1 sends a downlink frame (e.g., a downlink frame) on the second link without transmitting an initial control frame (e.g., MU-RTS trigger frame or BSRP trigger frame) , data frame, PPDU, MPDU, A-MPDU) can be transmitted to STA MLD 1. If it is confirmed that the EMLSR operation of STA MLD 1 is stopped, AP MLD 1 may transmit a downlink frame to STA MLD 1 on the second link without transmitting an initial control frame. STA MLD 1 can receive the downlink frame of AP MLD 1 without EMLSR operation.

Before AP MLD 1 transmits link interruption information to STA MLD 1, a preliminary operation to change EMLSR operation may be performed. Alternatively, after AP MLD 1 transmits link outage information to STA MLD 1, a post-operation to change EMLSR operation may be performed. For example, AP MLD 1 and STA MLD 1 can change EMLSR operation before or after transmission of link outage information by exchanging EHT action frames (e.g., EML OMN frames).

For example, AP MLD 1 may indicate discontinuation of use of one link (e.g., the first link) among the EMLSR links (e.g., the first link and the second link) of STA MLD 1. Discontinuation of use of one link may be indicated by link discontinuation information of AP MLD 1. Before transmitting link usage interruption information, AP MLD 1 may indicate suspension of EMLSR operation by transmitting an EML OMN frame to STA MLD 1. Alternatively, after receiving link interruption information, STA MLD 1 may indicate suspension of EMLSR operation by transmitting an EML OMN frame to AP MLD 1. Alternatively, after transmitting link usage interruption information, AP MLD 1 may indicate suspension of EMLSR operation by transmitting an EML OMN frame to STA MLD 1. The EML OMN frame of AP MLD 1 and/or STA MLD 1 may request suspension of EMLSR operation.

Alternatively, after receiving the link discontinuation frame of AP MLD 1, STA MLD 1 may not stop EMLSR operation on the second link. AP MLD 1 may transmit an initial control frame to STA MLD 1 for transmission of a downlink frame. Since only one of the EMLSR links of STA MLD 1 (e.g., the second link) is available, AP MLD 1 sends an initial control frame to STA MLD 1 without considering the EMLSR padding delay and/or EMLSR transition delay. Can be transmitted. In other words, the EMLSR padding delay and/or EMLSR transition delay may be considered or set to zero. The EMLSR padding delay or/and the EMLSR transition delay of STA MLD 1 may be considered or set to 0, and STA MLD 1 may be set to "transition operation from listening operation to normal transmit/receive operation" or "transition operation from normal transmit/receive operation to listen operation" The “action” can be performed without delay.

In the above embodiment, the EMLSR operation can be interpreted as an EMLMR operation. For example, an EMLSR link may be an EMLMR link, and STA MLD 1 may perform an EMLMR operation. In other words, STA MLD 1 may be EMLMR STA MLD. EMLSR padding delay and EMLSR transition delay can be interpreted as EMLMR padding delay and EMLMR transition delay, respectively.

FIG. 8B is a timing diagram illustrating a fourth embodiment of a link change method for an EMLSR device in a wireless LAN supporting multiple links.

Referring to FIG. 8B, STA MLD 1 may include STA 1-1 operating on the first link, STA 1-2 operating on the second link, and STA 1-3 operating on the third link. The operation of STA MLD 1 in the first link may be interpreted as the operation of STA 1-1, the operation of STA MLD 1 in the second link may be interpreted as the operation of STA 1-2, and the operation of STA MLD in the third link may be interpreted as the operation of STA 1-1. The operation of 1 can be interpreted as the operation of STA 1-3. STA MLD 1 can perform EMLSR operations on the first link, second link, and third link. In other words, STA MLD 1 may be an EMLSR device (eg, EMLSR STA MLD or EMLSR non-AP MLD). AP MLD 1 may include AP 1-1 operating on the first link, AP 1-2 operating on the second link, and AP 1-3 operating on the third link. The operation of AP MLD 1 in the first link can be interpreted as the operation of AP 1-1, the operation of AP MLD 1 in the second link can be interpreted as the operation of AP 1-2, and the operation of AP MLD in the third link The operation of 1 can be interpreted as the operation of AP 1-3.

AP MLD 1 (e.g., AP 1-1) sends a frame (e.g., a beacon frame or EHT action frame) containing TID-to-link mapping information to STA MLD 1 (e.g., STA 1-1 ) can be transmitted to. Beacon frames may be transmitted in a broadcast manner, and EHT action frames may be transmitted in a unicast manner. TID-to-link mapping information transmitted from the AP MLD to the STA MLD may indicate discontinuation of link use. For example, if a specific link is not mapped to any TID in the TID-to-link mapping information, the TID-to-link mapping information may indicate discontinuation of use of the specific link. If the use of a specific link is stopped, all transmission and reception operations may not be performed on the specific link.

For example, AP MLD 1 may transmit a beacon frame containing TID-to-link mapping information to STA MLD 1. A beacon frame (eg, TID-to-link mapping information) transmitted by AP MLD 1 may indicate discontinuation of use of the first link. The beacon frame of AP MLD 1 may include information on the time of discontinuation of use of the first link. A beacon frame indicating discontinuation of use of the first link may be referred to as link discontinuation information (eg, link discontinuation frame). STA MLD 1 may receive a beacon frame (e.g., a link disablement frame) from AP MLD 1, and information elements included in the beacon frame (e.g., TID-to-link mapping information and/or enable Information at the time of interruption) can be checked. STA MLD 1 can confirm that use of the first link is discontinued. Additionally, STA MLD 1 can confirm when the first link is discontinued. STA MLD 1 may perform communication using the second link and the third link after the first link ceases use. In other words, after the point of discontinuation of the first link, STA 1-2 can perform communication on the second link, STA 1-3 can perform communication on the third link, and STA 1-1 can perform communication on the third link. Communication may not be performed on the first link.

STA MLD 1 (e.g., EMLSR STA MLD) may interpret AP MLD 1's instruction to stop using the link as stopping EMLSR operation or resetting EMLSR operation. After the point of discontinuation of use of the first link, STA MLD 1 may not perform a listening operation on the first link and may perform an EMLSR operation on the second link and the third link. Prior to the decommissioning of the first link, the EMLSR links may include a first link, a second link, and a third link, and after the decommissioning of the first link, the EMLSR links may include a second link and a third link. It can be included. STA MLD 1 may re-establish EMLSR links based on AP MLD1's link discontinuation instruction. STA MLD 1 may perform EMLSR operations (e.g., listen operations) on the first link, the second link, and the third link before the outage of the first link, and after the outage of the first link. An EMLSR operation (eg, a listening operation) may be performed on the second link and the third link.

STA MLD 1 may not use the first link after the first link stops being used. In other words, STA MLD 1 may perform listening operations on the second link and the third link to receive downlink frames after the first link ceases use. In the downlink communication procedure between AP MLD 1 and STA MLD 1 after the point of outage of the first link, AP MLD 1 sends an initial control frame (e.g., MU-RTS trigger frame or BSRP) on the second or third link. After transmitting the trigger frame), a downlink frame (e.g., data frame, PPDU, MPDU, A-MPDU) may be transmitted to STA MLD 1. In other words, if STA MLD 1 is confirmed to be performing the EMLSR operation, AP MLD 1 may transmit a downlink frame to STA MLD 1 after transmitting the initial control frame on the second link or the third link. STA MLD 1 can receive the downlink frame of AP MLD 1 based on EMLSR operation. STA MLD 1 may perform an EMLSR operation on the second link and/or a third link, and may receive a downlink frame according to the EMLSR operation.

Before AP MLD 1 transmits link interruption information to STA MLD 1, a preliminary operation to change EMLSR operation may be performed. Alternatively, after AP MLD 1 transmits link outage information to STA MLD 1, a post-operation to change EMLSR operation may be performed. For example, AP MLD 1 and STA MLD 1 can change EMLSR operation before or after transmission of link outage information by exchanging EHT action frames (e.g., EML OMN frames).

For example, AP MLD 1 suspends use of one link (e.g., the first link) of STA MLD 1's EMLSR links (e.g., the first link, the second link, and the third link). You can instruct. Discontinuation of use of one link may be indicated by link discontinuation information of AP MLD 1. Before transmitting link usage interruption information, AP MLD 1 may indicate a change in the link on which the EMLSR operation is performed by transmitting an EML OMN frame to STA MLD 1. Alternatively, after receiving link outage information, STA MLD 1 may indicate a change in the link on which the EMLSR operation is performed by transmitting an EML OMN frame to AP MLD 1. Alternatively, after transmitting link usage interruption information, AP MLD 1 may indicate a change in the link on which the EMLSR operation is performed by transmitting an EML OMN frame to STA MLD 1. The EML OMN frame of AP MLD 1 and/or STA MLD 1 may request suspension of EMLSR operation. The EML OMN frame of AP MLD 1 and/or STA MLD 1 may indicate a change in the link on which the EMLSR operation is performed. A change in a link may mean a re-establishment of the link.

In the above embodiment, the EMLSR operation can be interpreted as an EMLMR operation. For example, an EMLSR link may be an EMLMR link, and STA MLD 1 may perform an EMLMR operation. In other words, STA MLD 1 may be EMLMR STA MLD. EMLSR padding delay and EMLSR transition delay can be interpreted as EMLMR padding delay and EMLMR transition delay, respectively.

Figure 9 is a timing diagram illustrating a first embodiment of a link change method in a wireless LAN supporting multiple links.

Referring to FIG. 9, STA MLD 1 may include STA 1-1 operating on a first link and STA 1-2 operating on a second link. The operation of STA MLD 1 in the first link may be interpreted as the operation of STA 1-1, and the operation of STA MLD 1 in the second link may be interpreted as the operation of STA 1-2. AP MLD 1 may include AP 1-1 operating on the first link and AP 1-2 operating on the second link. The operation of AP MLD 1 in the first link can be interpreted as the operation of AP 1-1, and the operation of AP MLD 1 in the second link can be interpreted as the operation of AP 1-2.

AP MLD 1 may transmit a link recommendation frame (eg, EHT action frame) to STA MLD 1. EHT action frames can be used to recommend links. AP MLD can transmit link advisory frames using unicast or broadcast methods. The link advisory frame may include at least one of a link bitmap, a partial AID bitmap, or an AID bitmap. The link recommendation frame may include information indicating the link to be used for uplink and/or the link to be used for downlink.

For example, AP MLD 1 may transmit a link advisory frame to STA MLD 1. STA MLD 1 can receive a link advisory frame from AP MLD 1. The link recommendation frame of AP MLD 1 may recommend use of the second link. Interference due to hidden nodes may occur in the second link, and in this case, use of the second link may be impossible. Channel conditions may be poor on the second link, in which case use of the second link may be impossible. Use of the second link may be impossible for other reasons.

If the second link is unavailable, STA MLD 1 may transmit a link advisory rejection frame (eg, link advisory response frame) to AP MLD 1. The link recommendation rejection frame can be a separate EHT action frame or an arbitrary frame. The type (eg, format) of the link recommendation rejection frame may be the same or similar to the type (eg, format) of the link recommendation frame. AP MLD 1 may receive a link advisory rejection frame from STA MLD 1. When a link recommendation rejection frame is received, AP MLD 1 may determine that the second link recommended by the link recommendation frame is unusable.

AP MLD 1 may transmit a response frame (e.g., an acknowledgment (ACK) frame or a block ACK (BA) frame) to the link advisory rejection frame to STA MLD 1. Alternatively, transmission of the response frame to the link recommendation rejection frame may be omitted. Due to the link advisory rejection frame of STA MLD 1, the communication operations and settings (e.g., EMLSR operation/setting, uplink operation/setting, downlink operation/setting) between AP MLD 1 and STA MLD 1 may not be changed. there is.

The link recommendation rejection frame transmitted from STA MLD 1 to AP MLD 1 may include a list (e.g., information) of links preferred by STA MLD 1. The link preferred by STA MLD 1 may be the link that STA MLD 1 wishes to use. AP MLD 1 can confirm the link preferred by STA MLD 1 based on the information included in the link recommendation rejection frame, and can transmit a link recommendation frame considering the link preferred by STA MLD 1. The stopping procedure and/or resetting procedure of the EMLSR operation according to the embodiment of FIG. 7A and/or the embodiment of FIG. 7B described above may be performed. Operations according to the link recommendation rejection frame of FIG. 9 may be applied to the embodiment(s) of FIGS. 7A, 7B, 8A, and/or 8B.

In the above embodiment, the EMLSR operation can be interpreted as an EMLMR operation. For example, an EMLSR link may be an EMLMR link, and STA MLD 1 may perform an EMLMR operation. In other words, STA MLD 1 may be EMLMR STA MLD. EMLSR padding delay and EMLSR transition delay can be interpreted as EMLMR padding delay and EMLMR transition delay, respectively.

FIG. 10 is a timing diagram illustrating a fifth embodiment of a link change method for an EMLSR device in a wireless LAN supporting multiple links.

Referring to FIG. 10, STA MLD 1 may include STA 1-1 operating on a first link and STA 1-2 operating on a second link. The operation of STA MLD 1 in the first link may be interpreted as the operation of STA 1-1, and the operation of STA MLD 1 in the second link may be interpreted as the operation of STA 1-2. STA MLD 1 can perform EMLSR operation on the first link and the second link. In other words, STA MLD 1 may be an EMLSR device (eg, EMLSR STA MLD or EMLSR non-AP MLD). The first link and the second link may be EMLSR links. AP MLD 1 may include AP 1-1 operating on the first link and AP 1-2 operating on the second link. The operation of AP MLD 1 in the first link can be interpreted as the operation of AP 1-1, and the operation of AP MLD 1 in the second link can be interpreted as the operation of AP 1-2.

AP MLD 1 (e.g., AP 1-1) sends a frame (e.g., a beacon frame or EHT action frame) containing TID-to-link mapping information to STA MLD 1 (e.g., STA 1-1 ) can be transmitted to. Beacon frames may be transmitted in a broadcast manner, and EHT action frames may be transmitted in a unicast manner. TID-to-link mapping information transmitted from AP MLD 1 to STA MLD 1 may indicate discontinuation of link use. For example, if a specific link is not mapped to any TID in the TID-to-link mapping information, the TID-to-link mapping information may indicate discontinuation of use of the specific link. If the use of a specific link is stopped, all transmission and reception operations may not be performed on the specific link.

For example, AP MLD 1 may transmit a beacon frame containing TID-to-link mapping information to STA MLD 1. A beacon frame (eg, TID-to-link mapping information) transmitted by AP MLD 1 may indicate discontinuation of use of the first link. Discontinuation of use of the first link may mean disabling the first link. The beacon frame of AP MLD 1 may include information on the time of discontinuation of use of the first link. A beacon frame or EHT action frame indicating discontinuation of use of the first link may be referred to as link discontinuation information (eg, link discontinuation frame). Link outage information may also be transmitted on the second link. In other words, link outage information may be transmitted on the first link and the second link. STA MLD 1 may receive a beacon frame (e.g., a link disablement frame) from AP MLD 1, and information elements included in the beacon frame (e.g., TID-to-link mapping information and/or enable Information at the time of interruption) can be checked. STA MLD 1 can confirm that use of the first link is discontinued. Additionally, STA MLD 1 can confirm when the first link is discontinued.

After the point of discontinuation of use of the first link, use of the first link may be discontinued. STA 1-2 of STA MLD 1 may transmit a spatial multiplexing power saving (SMPS) frame to AP 1-2 on the second link. For example, the SMPS frame may be transmitted when at least one of the EMLSR links (eg, an available link) remains. The SMPS frame may indicate the use of SMPS and/or SMPS mode. SMPS mode can be classified into dynamic SMPS mode and static SMPS mode. The SMPS frame may be a high throughput (HT) action frame. STA 1-2 may transmit an SMPS frame containing information indicating that the dynamic SMPS mode is used to AP 1-2.

AP 1-2 may receive an SMPS frame from STA 1-2 and may transmit a response frame (e.g., ACK frame) for the SMPS frame to STA 1-2. AP 1-2 can check the information element(s) included in the SMPS frame. For example, AP 1-2 can confirm that STA 1-2 is operating in dynamic SMPS mode based on the information element(s) included in the SMPS frame. STA 1-2 may perform the SMPS operation instead of the listening operation after transmitting the SMPS frame. In other words, STA 1-2 may not perform the EMLSR operation after transmission of the SMPS frame. EMLSR operations may be suspended.

AP 1-2 may not transmit an initial control frame (eg, EMLSR initial control frame) to transmit a data frame to STA 1-2. If it is confirmed that STA 1-2 does not perform the EMLSR operation, AP 1-2 may not transmit an initial control frame to transmit a data frame to STA 1-2. STA 1-2 may not receive an initial control frame to receive a data frame from AP 1-2. In other words, the initial control frame may not be needed in the data transmission procedure between AP 1-2 and STA 1-2. When STA 1-2 operates in dynamic SMPS mode, AP 1-2 can transmit the first frame to STA 1-2 using one spatial stream. The first frame may be an RTS frame or a data frame. STA 1-2 can receive the first frame from AP 1-2 and transmit a response to the first frame to AP 1-2. When a response to the first frame is received, AP 1-2 may transmit a frame (e.g., a second frame) to STA 1-2 using multiple spatial streams. Alternatively, STA 1-2 may operate in static SMPS mode. In this case, AP 1-2 may transmit frame(s) to STA 1-2 using one spatial stream.

AP 1-2 may indicate the start of use of the first link. In other words, AP 1-2 may transmit information indicating the start of use of the first link. Initiation of use of the first link may mean enabling of the first link. For example, AP MLD 1 may perform TID-to-link mapping for the first link again. AP MLD 1 may perform TID-to-link mapping again so that at least one TID is mapped to the first link. AP MLD 1 (e.g., AP 1-2) sends a frame (e.g., a beacon frame or EHT action frame) containing TID-to-link mapping information to STA MLD 1 (e.g., STA 1-2 ) can be transmitted to. Beacon frames may be transmitted in a broadcast manner, and EHT action frames may be transmitted in a unicast manner. STA MLD 1 can receive TID-to-link mapping information from AP MLD 1 and confirm that use of the first link is initiated based on the TID-to-link mapping information. In other words, STA MLD 1 can confirm that the first link is enabled based on TID-to-link mapping information.

Use of the first link may begin from the point in time when AP 1-2 indicates the start of use of the first link or from a separate point in time indicated by AP 1-2. Alternatively, when a beacon frame (eg, a beacon frame indicating initiation of use of the first link) is received on the first link, use of the first link may be initiated. A beacon frame or action frame (eg, EHT action frame) indicating the start of use of the first link transmitted by AP MLD 1 may be referred to as link use start information. Link use start information of AP MLD 1 may also be transmitted on the second link. In other words, link use start information of AP MLD 1 may be transmitted on the first link and the second link.

“When use of the first link is initiated” or “When STA 1-1 receives a beacon frame from AP 1-1 on the first link after use of the first link is initiated”, STA 1-1 in STA MLD 1 can perform a listening operation. “When use of the first link is initiated” or “When STA 1-1 receives a beacon frame from AP 1-1 on the first link after use of the first link is initiated”, STA 1-2 in STA MLD 1 can stop SMPS operation and perform listening operation. AP MLD 1 may transmit an initial control frame to STA MLD 1 in order to transmit a frame to STA MLD 1. Alternatively, STA 1-2 can stop SMPS operation by sending an SMPS frame to AP 1-2. The SMPS frame of STA 1-2 may indicate that SMPS operation is stopped.

In the above embodiment, the start and/or stoppage of SMPS operation is indicated by a frame according to the (re)association procedure (e.g., (re)connection request frame, (re)connection response frame) instead of the SMPS frame. It can be. For example, AP 1-2 and STA 1-2 may perform a (re)connection procedure, and SMPS operation may be started or stopped in the (re)connection procedure.

In the above embodiment, the EMLSR operation can be interpreted as an EMLMR operation. For example, an EMLSR link may be an EMLMR link, and STA MLD 1 may perform an EMLMR operation. In other words, STA MLD 1 may be EMLMR STA MLD. EMLSR padding delay and EMLSR transition delay can be interpreted as EMLMR padding delay and EMLMR transition delay, respectively.

FIG. 11 is a timing diagram illustrating a sixth embodiment of a link change method for an EMLSR device in a wireless LAN supporting multiple links.

Referring to FIG. 11, STA MLD 1 may include STA 1-1 operating on a first link and STA 1-2 operating on a second link. The operation of STA MLD 1 in the first link may be interpreted as the operation of STA 1-1, and the operation of STA MLD 1 in the second link may be interpreted as the operation of STA 1-2. STA MLD 1 can perform EMLSR operation on the first link and the second link. In other words, STA MLD 1 may be an EMLSR device (eg, EMLSR STA MLD or EMLSR non-AP MLD). The first link and the second link may be EMLSR links. AP MLD 1 may include AP 1-1 operating on the first link and AP 1-2 operating on the second link. The operation of AP MLD 1 in the first link can be interpreted as the operation of AP 1-1, and the operation of AP MLD 1 in the second link can be interpreted as the operation of AP 1-2.

AP MLD 1 (e.g., AP 1-1) sends a frame (e.g., a beacon frame or EHT action frame) containing TID-to-link mapping information to STA MLD 1 (e.g., STA 1-1 ) can be transmitted to. Beacon frames may be transmitted in a broadcast manner, and EHT action frames may be transmitted in a unicast manner. TID-to-link mapping information transmitted from AP MLD 1 to STA MLD 1 may indicate discontinuation of link use. For example, if a specific link is not mapped to any TID in the TID-to-link mapping information, the TID-to-link mapping information may indicate discontinuation of use of the specific link. If the use of a specific link is stopped, all transmission and reception operations may not be performed on the specific link.

For example, AP MLD 1 may transmit a beacon frame containing TID-to-link mapping information to STA MLD 1. A beacon frame (eg, TID-to-link mapping information) transmitted by AP MLD 1 may indicate discontinuation of use of the first link. Discontinuation of use of the first link may mean disabling the first link. The beacon frame of AP MLD 1 may include information on the time of discontinuation of use of the first link. A beacon frame or EHT action frame indicating discontinuation of use of the first link may be referred to as link discontinuation information (eg, link discontinuation frame). Link outage information may also be transmitted on the second link. In other words, link outage information may be transmitted on the first link and the second link. STA MLD 1 may receive a beacon frame (e.g., a link disablement frame) from AP MLD 1, and information elements included in the beacon frame (e.g., TID-to-link mapping information and/or enable Information at the time of interruption) can be checked. STA MLD 1 can confirm that use of the first link is discontinued. Additionally, STA MLD 1 can confirm when the first link is discontinued.

After the point of discontinuation of use of the first link, use of the first link may be discontinued. STA 1-2 of STA MLD 1 does not perform listening operations and can operate in dynamic SMPS mode without transmitting separate frames. In other words, STA 1-2 may suspend (e.g., temporarily suspend) EMLSR operation. AP 1-2 may not transmit an initial control frame (eg, EMLSR initial control frame) to STA 1-2. When STA 1-2 operates in dynamic SMPS mode, AP 1-2 can transmit the first frame to STA 1-2 using one spatial stream. The first frame may be an RTS frame or a data frame. STA 1-2 can receive the first frame from AP 1-2 and transmit a response to the first frame to AP 1-2. When a response to the first frame is received, AP 1-2 may transmit a frame (e.g., a second frame) to STA 1-2 using multiple spatial streams. Alternatively, STA 1-2 can operate in static SMPS mode. In this case, AP 1-2 may transmit frame(s) to STA 1-2 using one spatial stream.

STA MLD 1 may not receive information from AP MLD 1 indicating discontinuation of use of the first link. In this case, STA MLD 1 can perform EMLSR operation on the first link and the second link. AP 1-2 may transmit a frame other than the initial control frame to STA 1-2. STA 1-2 may not receive the frame transmitted by AP 1-2. In this case, STA 1-2 may not be able to transmit a response to AP 1-2's frame. If a response to AP 1-2's frame is not received, AP 1-2 may determine that STA 1-2 is not performing the SMPS operation. In other words, AP 1-2 may determine that STA 1-2 is performing the EMLSR operation instead of the SMPS operation. If it is determined that STA 1-2 is performing an EMLSR operation, AP 1-2 may transmit an initial control frame (e.g., EMLSR initial control frame) to STA 1-2.

AP 1-2 may indicate the start of use of the first link. In other words, AP 1-2 may transmit information indicating the start of use of the first link. Initiating use of the first link may mean enabling the first link. For example, AP MLD 1 may perform TID-to-link mapping for the first link again. AP MLD 1 may perform TID-to-link mapping again so that at least one TID is mapped to the first link. AP MLD 1 (e.g., AP 1-2) sends a frame (e.g., a beacon frame or EHT action frame) containing TID-to-link mapping information to STA MLD 1 (e.g., STA 1-2 ) can be transmitted to. Beacon frames may be transmitted in a broadcast manner, and EHT action frames may be transmitted in a unicast manner. STA MLD 1 can receive TID-to-link mapping information from AP MLD 1 and confirm that use of the first link is initiated based on the TID-to-link mapping information. In other words, STA MLD 1 can confirm that the first link is enabled based on TID-to-link mapping information.

Use of the first link may begin from the point in time when AP 1-2 indicates the start of use of the first link or from a separate point in time indicated by AP 1-2. Alternatively, when a beacon frame (eg, a beacon frame indicating initiation of use of the first link) is received on the first link, use of the first link may be initiated. A beacon frame or action frame (eg, EHT action frame) indicating the start of use of the first link transmitted by AP MLD 1 may be referred to as link use start information. Link use start information of AP MLD 1 may also be transmitted on the second link. In other words, link use start information of AP MLD 1 may be transmitted on the first link and the second link.

“When use of the first link is initiated” or “When STA 1-1 receives a beacon frame from AP 1-1 on the first link after use of the first link is initiated”, STA 1-1 in STA MLD 1 can perform a listening operation. “When use of the first link is initiated” or “When STA 1-1 receives a beacon frame from AP 1-1 on the first link after use of the first link is initiated”, STA 1-2 in STA MLD 1 can stop SMPS operation and perform listening operation. AP MLD 1 may transmit an initial control frame to STA MLD 1 in order to transmit a frame to STA MLD 1. Alternatively, STA 1-2 can stop SMPS operation by sending an SMPS frame to AP 1-2. The SMPS frame of STA 1-2 may indicate that SMPS operation is stopped.

In the above embodiment, the start and/or stoppage of SMPS operation is indicated by a frame according to the (re)association procedure (e.g., (re)connection request frame, (re)connection response frame) instead of the SMPS frame. It can be. For example, AP 1-2 and STA 1-2 may perform a (re)connection procedure, and SMPS operation may be started or stopped in the (re)connection procedure.

The above embodiment can be performed based on the EMLSR setup procedure between AP MLD 1 and STA MLD 1. The control field shown in FIG. 12 can be used in the EMLSR setup procedure.

In the above embodiment, the EMLSR operation can be interpreted as an EMLMR operation. For example, an EMLSR link may be an EMLMR link, and STA MLD 1 may perform an EMLMR operation. In other words, STA MLD 1 may be EMLMR STA MLD. EMLSR padding delay and EMLSR transition delay can be interpreted as EMLMR padding delay and EMLMR transition delay, respectively.

Figure 12 is a block diagram showing a first embodiment of a control field format for EMLSR configuration between AP MLD and STA MLD.

Referring to FIG. 12, a frame including an enhanced multi-link (EML) control field may be transmitted and received in an EMLSR setup procedure and/or an enhanced multi-link multi-radio (EMLMR) setup procedure. The EML control field may be included in an EML OMN (operating mode notification) frame. The EMLSR mode field set to 1 may indicate that the STA MLD or STA transmitting the EML control field intends to use EMLSR. If the EMLSR mode field is set to 1, the EML control field (e.g., EML control field format) may include an EMLSR implicit SMPS field. Even if the EMLSR mode field is set to 0, the EML control field may include an EMLSR implicit SMPS field.

The EMLSR implicit SMPS field may contain one or more bits. “If the EMLSR implicit SMPS field contains 1 bit, the EMLSR implicit SMPS field is set to 1, and the STA MLD or STA transmitting the EML control field can use one of the EMLSR links.” , the STA MLD or STA may implicitly perform SMPS operation on an available link, as in the embodiment of FIGS. 8A and/or 8B. The EMLSR implicit SMPS field set to 0 means (e.g., an indication) that "the STA MLD or STA will not implicitly perform SMPS operations on the available links even if one of the EMLSR links is available." can do. Even when the STA MLD or STA performs the EMLMR operation, "the EMLSR implicit SMPS field contains 1 bit, the EMLSR implicit SMPS field is set to 1, and the STA MLD or STA transmitting the EML control field “If one of the EMLSR links is available,” the STA MLD or STA may implicitly perform SMPS operation on the available link as in the embodiment of FIGS. 8A and/or 8B.

The operation of the method according to the embodiment of the present disclosure can be implemented as a computer-readable program or code on a computer-readable recording medium. Computer-readable recording media include all types of recording devices that store information that can be read by a computer system. Additionally, computer-readable recording media can be distributed across networked computer systems so that computer-readable programs or codes can be stored and executed in a distributed manner.

Additionally, computer-readable recording media may include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, or flash memory. Program instructions may include not only machine language code such as that created by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like.

Although some aspects of the disclosure have been described in the context of an apparatus, it may also refer to a corresponding method description, where a block or device corresponds to a method step or feature of a method step. Similarly, aspects described in the context of a method may also be represented by corresponding blocks or items or features of a corresponding device. Some or all of the method steps may be performed by (or using) a hardware device, such as, for example, a microprocessor, programmable computer, or electronic circuit. In some embodiments, at least one or more of the most important method steps may be performed by such a device.

In embodiments, a programmable logic device (e.g., a field programmable gate array) may be used to perform some or all of the functionality of the methods described herein. In embodiments, a field-programmable gate array may operate in conjunction with a microprocessor to perform one of the methods described herein. In general, the methods are preferably performed by some hardware device.

Although the present disclosure has been described above with reference to preferred embodiments, those skilled in the art may modify and change the present disclosure in various ways without departing from the spirit and scope of the present disclosure as set forth in the claims below. You will understand that it is possible.

Claims (20)

As a method of the first device,
Receiving, in a first link among multiple links, a first frame including first information indicating discontinuation of use of the first link from a second device; and
Comprising the step of performing a first communication with the second device on a second link among the multiple links, the interruption of use of which is not indicated by the first frame,
The second communication between the first device and the second device is not performed on the first link whose use is indicated by the first frame.
Method of the first device. In claim 1,
The first frame further includes second information indicating a point in time when use of the first link is stopped, and the first communication between the first device and the second device in the second link is performed from the point in time when use is stopped. and the first link is not used from the time of discontinuation of use,
Method of the first device. In claim 1,
The first information is traffic identifier (TID)-to-link mapping information, and there is no TID mapped to the first link in the TID-to-link mapping information.
Method of the first device. In claim 1,
The step of performing first communication with the second device includes:
receiving a data frame from the second device on the second link without receiving an initial control frame from the second device; and
Comprising transmitting a response frame for the data frame to the second device on the second link,
Method of the first device. In claim 1,
"The first device supports enhanced multi-link single radio (EMLSR) operation, the first link and the second link are EMLSR links, and the EMLSR links are When only one link is available, the EMLSR operation of the first device is stopped,
Method of the first device. In claim 1,
The first frame is a beacon frame or an extreme high throughput (EHT) action frame,
Method of the first device. In claim 1,
The first device is a station (STA) multi-link device (MLD), and the first device includes a first STA operating on the first link and a second STA operating on the second link, and the first device includes a first STA operating on the first link and a second STA operating on the second link. The second device is an access point (AP) MLD, and the second device includes a first AP operating on the first link and a second AP operating on the second link.
Method of the first device. As a method of the first device,
Receiving, in a first link among multiple links, a first frame including first information indicating discontinuation of use of the first link from a second device; and
A step of performing a listening operation on a second link and a third link among the multiple links that are not indicated to be discontinued by the first frame,
Communication between the first device and the second device is not performed on the first link whose use is indicated by the first frame.
Method of the first device. In claim 8,
The first frame further includes second information indicating a point in time when use of the first link is stopped, and the first link is not used from the point in time when use is stopped.
Method of the first device. In claim 9,
Prior to the point of discontinuation of use, the enhanced multi-link single radio (EMLSR) links include the first link, the second link, and the third link, and after the point of discontinuation of use, the EMLSR links include the second link. link and the third link, wherein the EMLSR links are reestablished based on the first frame,
Method of the first device. In claim 8,
The first information is traffic identifier (TID)-to-link mapping information, and there is no TID mapped to the first link in the TID-to-link mapping information.
Method of the first device. In claim 8,
The method of the first device is,
Receiving an initial control frame from the second device on one of the second link and the third link; and
After receiving the initial control frame, receiving a data frame from the second device on the one link,
Method of the first device. In claim 8,
The first device is a station (STA) multi-link device (MLD), and the first device includes a first STA operating on the first link, a second STA operating on the second link, and the third link. Includes a third STA operating in, wherein the second device is an access point (AP) MLD, and the second device includes a first AP operating on the first link, a second AP operating on the second link, And a third AP operating on the third link,
Method of the first device. As a method of the second device,
generating a first frame including first information indicating discontinuation of use of a first link among multiple links;
transmitting the first frame to a first device on the first link; and
Comprising: performing a first communication with the first device on a second link among the multiple links, the interruption of use of which is not indicated by the first frame,
The second communication between the first device and the second device is not performed on the first link whose use is indicated by the first frame.
Method of second device. In claim 14,
The step of performing first communication with the first device includes:
When the second device does not perform an enhanced multi-link single radio (EMLSR) operation, transmitting a data frame to the first device without transmitting an initial control frame on the second link,
Method of second device. In claim 14,
The step of performing first communication with the first device includes:
When the second device performs an EMLSR operation, transmitting an initial control frame to the first device on the second link; and
After transmitting the initial control frame, transmitting a data frame on the second link to the first device,
Method of second device. In claim 14,
The first information is traffic identifier (TID)-to-link mapping information, and there is no TID mapped to the first link in the TID-to-link mapping information.
Method of second device. In claim 14,
"The first device supports EMLSR operation, the first link and the second link are EMLSR links, and only one link of the EMLSR links is available due to a discontinuation instruction according to the first frame. ", the EMLSR operation of the first device is stopped,
Method of second device. In claim 14,
The first frame further includes second information indicating a point in time when use of the first link is stopped, and the first link is not used from the point in time when use is stopped.
Method of second device. In claim 19,
Prior to the point of discontinuation, the EMLSR links include the first link, the second link, and the third link, and after the point of discontinuation, the EMLSR links include the second link and the third link. and the EMLSR links are reset based on the first frame,
Method of second device.

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