Method and apparatus for using resources in wireless local area network supporting MLSR

Abstract

A method and an apparatus for using resources in a wireless local area network supporting MLSR are disclosed. A method of a first STA comprises the steps of: operating in a listening state on a first link; receiving an initial control frame from the first AP on the first link; changing an operation state of the first STA from a listening state to a normal transmission / reception state after receiving the initial control frame; determining whether one or more state retention conditions are satisfied during a preset time; and maintaining or changing the operating state of the first STA based on whether the one or more state maintaining conditions are satisfied.

Description

Technical Field

[0001] The present invention relates to wireless local area network (WLAN) communication technology, and more particularly, to a technique for using resources in a wireless local area network that supports multi-link single radio (MLSR). Background Art

[0002] Recently, with the popularization of mobile devices, wireless local area network technology that can provide fast wireless communication services to mobile devices has received attention. Wireless local area network technology may be a technology that supports mobile devices (e.g., smart phones, smart tablets, laptop computers, portable multimedia players, embedded devices, etc.) to access the Internet wirelessly based on wireless communication technology.

[0003] Standards for using wireless local area network technology are mainly standardized as IEEE 802.11 standards in the Institute of Electrical and Electronics Engineers (IEEE). With the development and popularization of the above wireless local area network technology, applications using wireless local area network technology have become diversified, and there has been a demand for wireless local area network technology that supports higher throughput.

[0004] As applications that require higher throughput and applications that require real-time transmission have emerged, a wireless local area network can support communication using an extended frequency bandwidth and an efficient retransmission operation. In addition, a wireless local area network can support an operation of simultaneously using multiple channels or multiple links. In other words, a wireless local area network can support multi-link transmission. In this case, a method for supporting efficient multi-link transmission may be required.

[0005] On the other hand, the technologies described in the background art section are written to enhance the understanding of the background of the present invention, and may include content that is not yet known to those of ordinary skill in the art to which the present invention pertains. Summary of the Invention

[0006] Technical Problem

[0007] In order to solve the above problems, the present invention is directed to providing a method and apparatus for using resources in a wireless local area network that supports multi-link single radio (MLSR).

[0008] Technical Solution

[0009] A method for a first STA to achieve the above object according to an embodiment of the present invention may include: operating in a listening state on a first link; receiving an initial control frame from a first AP on the first link; after receiving the initial control frame, changing the operating state of the first STA from the listening state to a normal transmission / reception state; determining whether one or more state holding conditions are satisfied within a preset time; and maintaining or changing the operating state of the first STA based on whether one or more state holding conditions are satisfied.

[0010] The one or more state holding conditions may include at least one of a first condition or a second condition. The first condition may be "a condition that the first STA receives a frame from another communication node", and the second condition may be "a condition that a frame to be transmitted to another communication node appears in the first STA".

[0011] The one or more state holding conditions may include at least one of a first condition or a second condition. The first condition may indicate that "a PHY-RXSTART.indication primitive appears in the PHY layer of the first STA", and the second condition may indicate that "the MAC layer of the first STA passes a PHY-TXSTART.request primitive to the PHY layer of the first STA, and the PHY layer of the first STA passes a PHY-TXSTART.confirm primitive to the MAC layer as a response to the PHY-TXSTART.request primitive".

[0012] When the one or more state holding conditions are satisfied, the first STA may maintain the normal transmission / reception state. When the one or more state holding conditions are not satisfied, the first STA may change the operating state from the normal transmission / reception state to the listening state.

[0013] The initial control frame may indicate TXOP sharing, and the first STA operating in the normal transmission / reception state may perform communication within the shared TXOP according to TXOP sharing.

[0014] When the mode of the TXOP sharing is TXOP sharing mode 1, the first STA may perform communication with the first AP within the shared TXOP. When the mode of the TXOP sharing is TXOP sharing mode 2, the first STA may perform communication with at least one of the first AP or another STA within the shared TXOP.

[0015] The method of the first STA may further include: receiving, from a first AP in a normal transmission / reception state, a MU-RTS frame indicating TXOP sharing, and the first STA operating in the normal transmission / reception state may perform communication within the shared TXOP according to the TXOP sharing.

[0016] The method of the first STA may further include: sending, on a first link, a CTS frame to the first AP as a response to an initial control frame, and the preset time may start from the end time of the transmission of the CTS frame.

[0017] The preset time may be aSIFSTime + aSlotTime + aRxPHYStartDelay.

[0018] In a listening state, the first STA may perform a listening operation to receive frames on one or more EMLSR links, and in a normal transmission / reception state, the first STA may perform communication on one link.

[0019] The first STA for achieving the above object according to an embodiment of the present invention may include at least one processor, and the at least one processor may cause the first STA to: operate in a listening state on a first link; receive an initial control frame from a first AP on the first link; after receiving the initial control frame, change the operation state of the first STA from the listening state to the normal transmission / reception state; determine whether one or more state holding conditions are satisfied within a preset time; and maintain or change the operation state of the first STA based on whether one or more state holding conditions are satisfied.

[0020] The one or more state holding conditions may include at least one of a first condition or a second condition. The first condition may be "a condition that the first STA receives a frame from another communication node", and the second condition may be "a condition that a frame to be sent to another communication node appears in the first STA".

[0021] The one or more state holding conditions may include at least one of a first condition or a second condition. The first condition may indicate that "a PHY-RXSTART.indication primitive appears in the PHY layer of the first STA", and the second condition may indicate that "the MAC layer of the first STA passes a PHY-TXSTART.request primitive to the PHY layer of the first STA, and the PHY layer of the first STA passes a PHY-TXSTART.confirm primitive to the MAC layer as a response to the PHY-TXSTART.request primitive".

[0022] When the one or more status retention conditions are satisfied, the first STA may maintain the normal transmission / reception state. When the one or more status retention conditions are not satisfied, the first STA may change the operation state from the normal transmission / reception state to the listening state.

[0023] The initial control frame may indicate TXOP sharing, and the first STA operating in the normal transmission / reception state may perform communication within the shared TXOP according to TXOP sharing.

[0024] When the mode of the TXOP sharing is TXOP sharing mode 1, the first STA may perform communication with the first AP within the shared TXOP. When the mode of the TXOP sharing is TXOP sharing mode 2, the first STA may perform communication with at least one of the first AP or another STA within the shared TXOP.

[0025] The at least one processor may further cause the first STA to receive a MU-RTS frame indicating TXOP sharing from the first AP in the normal transmission / reception state, and the first STA operating in the normal transmission / reception state may perform communication within the shared TXOP according to TXOP sharing.

[0026] The at least one processor may further cause the first STA to send a CTS frame to the first AP on the first link as a response to the initial control frame, and the preset time may start from the end time of the transmission of the CTS frame.

[0027] The preset time may be aSIFSTime + aSlotTime + aRxPHYStartDelay.

[0028] In the listening state, the first STA may perform a listening operation to receive frames on one or more EMLSR links, and in the normal transmission / reception state, the first STA may perform communication on one link.

[0029] Advantageous effects

[0030] According to the present invention, a multi-link single radio (MLSR) station (STA) in a wireless local area network can receive resource allocation information (e.g., communication resource allocation information) from an access point (AP) on multiple links. Before receiving the resource allocation information, the MLSR STA cannot perform operations of transmitting / receiving frames (e.g., data frames). When receiving the resource allocation information from the AP, the MLSR STA can maintain an operation state capable of transmitting / receiving frames in the resource section indicated by the resource allocation information. Alternatively, "when receiving the resource allocation information from the AP and there is a frame (e.g., data) to be transmitted by the MLSR STA in the resource section indicated by the resource allocation information", the MLSR STA can maintain an operation state capable of transmitting / receiving frames in the resource section indicated by the resource allocation information. Therefore, the MLSR STA can normally transmit / receive frames with the resources (e.g., resource sections) allocated by the AP, thereby enabling smooth communication to be performed. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a block diagram showing a first embodiment of a communication node constituting a wireless local area network system.

[0032] Figure 2 is a conceptual diagram showing a first embodiment of a multi-link configured between multi-link devices (MLDs).

[0033] Figure 3 is a timing diagram showing a first embodiment of a communication method of an EMLSR STA.

[0034] Figure 4 is a timing diagram showing a second embodiment of a communication method of an EMLSR STA.

[0035] Figure 5 is a timing diagram showing a third embodiment of a communication method of an EMLSR STA.

[0036] Figure 6 is a timing diagram showing a fourth embodiment of a communication method of an EMLSR STA.

[0037] Figure 7 is a timing diagram showing a fifth embodiment of a communication method of an EMLSR STA.

[0038] Figure 8 is a timing diagram showing a sixth embodiment of a communication method of an EMLSR STA.

[0039] Figure 9 is a timing diagram showing a seventh embodiment of a communication method of an EMLSR STA. DETAILED DESCRIPTION

[0040] Since the present invention can be modified in various ways and has various forms, specific exemplary embodiments will be shown in the accompanying drawings and described in detail in the detailed description. However, it should be understood that this is not intended to limit the present invention to the specific exemplary embodiments. On the contrary, the present invention is intended to cover all modifications and alternative forms falling within the spirit and scope of the present invention.

[0041] Relational terms such as first, second, etc. may be used to describe various elements, but these elements should not be limited by the terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of the present invention, the first component may be named the second component, and the second component may be similarly named the first component. The term "and / or" means any one or a combination of multiple related and described matters.

[0042] In an exemplary embodiment of the present invention, "at least one of A and B" may refer to "at least one of A or B" or "at least one of a combination of one or more of A and B". In addition, "one or more of A and B" may refer to "one or more of A or B" or "one or more of a combination of one or more of A and B".

[0043] When it is mentioned that a certain component is "coupled" or "connected" to another component, it should be understood that the certain component is directly "coupled" or "connected" to the other component, or other components may be arranged between them. On the contrary, when it is mentioned that a certain component is "directly coupled" or "directly connected" to another component, it should be understood that no other components are arranged between them.

[0044] The terms used in the present invention are only used to describe specific exemplary embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In the present invention, terms such as "comprising" or "having" are intended to indicate the presence of the features, values, steps, operations, components, parts, or combinations thereof described in the specification. However, it should be understood that these terms do not exclude the presence or addition of one or more features, values, steps, operations, components, parts, or combinations thereof.

[0045] Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Terms that are commonly used and have appeared in a dictionary should be interpreted as having a meaning that matches the contextual meaning in the art. In this specification, unless clearly defined, terms are not necessarily interpreted as having a formal meaning.

[0046] Hereinafter, the form of the present invention will be described in detail with reference to the accompanying drawings. When describing the present invention, for the sake of a comprehensive understanding of the present invention, the same reference numerals refer to the same elements throughout the description of the accompanying drawings, and their repeated description will be omitted.

[0047] Hereinafter, a wireless communication system applying an exemplary embodiment of the present invention will be described. The wireless communication system applying the exemplary embodiment of the present invention is not limited to the content described below, and can be applied to various wireless communication systems according to the exemplary embodiment of the present invention. The wireless communication system can be referred to as a "wireless communication network".

[0048] In an embodiment, "configuring an operation (e.g., a transmission operation)" may mean signaling "configuration information for an operation (e.g., an information element, a parameter)" and / or "information indicating the execution of an operation". "Configuring an information element (e.g., a parameter)" may mean signaling an information element. "Configuring a resource (e.g., a resource area)" may mean signaling configuration information of a resource. The frames proposed in the present invention can generally be referred to as a first frame, a second frame, a third frame, etc. The transmission time point of a frame may indicate a transmission start time point or a transmission end time point, and the reception time point of a frame may indicate a reception start time point or a reception end time point. The transmission time point may be interpreted as corresponding to the reception time point. A time point may be interpreted as time, and time may be interpreted as a time point.

[0049] Figure 1 is a block diagram showing a first exemplary embodiment of a communication node constituting a wireless local area network system.

[0050] As Figure 1 shown, the communication node 100 may be an access point, a station, an access point (AP) multi-link device (MLD), or a non-AP MLD. The access point may refer to an AP, and the station may refer to an STA or a non-AP STA. The operating channel width supported by the access point may be 20 megahertz (MHz), 80 MHz, 160 MHz, etc. The operating channel width supported by the station may be 20 MHz, 80 MHz, etc.

[0051] The communication node 100 may include at least one processor 110, a memory 120, and a plurality of transceivers 130 connected to a network to perform communication. The transceivers 130 may be referred to as transceivers, radio frequency (RF) units, RF modules, etc. In addition, the communication node 100 may further include an input interface device 140, an output interface device 150, a storage device 160, etc. The components included in the communication node 100 may be connected through a bus 170 to communicate with each other.

[0052] However, each component included in the communication node 100 may be connected through a separate interface or a separate bus centered on the processor 110 instead of the common bus 170. For example, the processor 110 may be connected to at least one of the memory 120, the transceiver 130, the input interface device 140, the output interface device 150, and the storage device 160 through a dedicated interface.

[0053] The processor 110 may execute at least one instruction stored in at least one of the memory 120 and the storage device 160. The processor 110 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor that executes a method according to an exemplary embodiment of the present invention. Each of the memory 120 and the storage device 160 may be configured as at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 120 may be configured with at least one of a read-only memory (ROM) and a random access memory (RAM).

[0054] Figure 2 It is a conceptual diagram showing a first exemplary embodiment of a multi-link configured between MLDs.

[0055] As Figure 2 shown, the MLD may have one medium access control (MAC) address. In an exemplary embodiment, the MLD may represent an AP MLD and / or a non-AP MLD. The MAC address of the MLD may be used during the multi-link establishment process between the non-AP MLD and the AP MLD. The MAC address of the AP MLD may be different from the MAC address of the non-AP MLD. Each of the APs associated with the AP MLD may have a different MAC address, and each of the stations (STAs) associated with the non-AP MLD may have a different MAC address. Each of the APs with different MAC addresses may be responsible for each of the multiple links supported by the AP MLD and may perform the role of an independent AP.

[0056] Each of the STAs with different MAC addresses can be responsible for each of multiple links supported by a non-AP MLD and can perform the role of an independent STA. The non-AP MLD can be referred to as a STA MLD. The MLD can support simultaneous transmit and receive (STR) operations. In this case, the MLD can perform a transmit operation in Link 1 and can perform a receive operation in Link 2. The MLD that supports the STR operation can be referred to as a STR MLD (e.g., STR AP MLD, STR non-AP MLD). In an exemplary embodiment, a link can represent a channel or a frequency band. A device that does not support the STR operation can be referred to as a non-STR (NSTR) AP MLD or NSTR non-AP MLD (or NSTR STA MLD).

[0057] The MLD can transmit and receive frames in multiple links (i.e., multi-links) by using a discontinuous bandwidth extension scheme (e.g., 80MHz + 80MHz). The multi-link operation can include multi-band transmission. The AP MLD can include multiple APs, and the multiple APs can operate in different links. Each of the multiple APs can perform the functions of a lower MAC layer. Each of the multiple APs can be referred to as a "communication node" or a "lower entity". The communication node (i.e., the AP) can operate under the control of a higher layer (or Figure 1 the processor 110 shown). The non-AP MLD can include multiple STAs, and the multiple STAs can operate in different links. Each of the multiple STAs can be referred to as a "communication node" or a "lower entity". The communication node (i.e., the STA) can operate under the control of a higher layer (or Figure 1 the processor 110 shown).

[0058] MLD can perform communication in multiple frequency bands (i.e., multi-band). For example, MLD can perform communication on the 2.4 GHz frequency band with an 80 MHz bandwidth according to a channel expansion scheme (e.g., bandwidth expansion scheme), and perform communication on the 5 GHz frequency band with a 160 MHz bandwidth according to a channel expansion scheme. MLD can perform communication with a 160 MHz bandwidth in the 5 GHz frequency band, and can perform communication with a 160 MHz bandwidth in the 6 GHz frequency band. One frequency band (e.g., one channel) utilized by MLD can be defined as one link. Alternatively, multiple links can be configured in one frequency band utilized by MLD. For example, MLD can configure one link in the 2.4 GHz frequency band and two links in the 6 GHz frequency band. Each link can be referred to as the first link, the second link, and the third link. Alternatively, each link can be referred to as link 1, link 2, and link 3. The link numbers can be set by the AP, and an identifier (ID) can be assigned to each link.

[0059] MLD (e.g., AP MLD and / or non-AP MLD) can configure multi-links by performing an access process and / or a negotiation process for multi-link operation. In this case, the number and / or the links to be utilized in the multi-links can be configured. The non-AP MLD (e.g., STA) can identify information about the frequency bands capable of communicating with the AP MLD. During the negotiation process of multi-link operation between the non-AP MLD and the AP MLD, the non-AP MLD can configure one or more of the links supported by the AP MLD for multi-link operation. Stations that do not support multi-link operation (e.g., IEEE 802.11a / b / g / n / ac / ax STA) can be connected to one or more of the links of the multi-links supported by the AP MLD.

[0060] When the frequency band interval between multiple links (e.g., the frequency band interval between Link 1 and Link 2 in the frequency domain) is sufficient, the MLD can perform the STR operation. For example, the MLD can use Link 1 among the multiple links to transmit a physical layer protocol data unit (PPDU) 1, and can use Link 2 among the multiple links to receive PPDU 2. On the other hand, if the MLD performs the STR operation when the frequency band interval between multiple links is insufficient, in-device coexistence (IDC) interference, i.e., interference between multiple links, may occur. Therefore, when the bandwidth interval between multiple links is insufficient, the MLD may not be able to perform the STR operation. Link pairs with the above interference relationship can be link pairs restricted by non-simultaneous transmit and receive (NSTR). Here, the MLD can be referred to as "NSTR AP MLD" or "NSTR non-AP MLD".

[0061] For example, a multi-link including Link 1, Link 2, and Link 3 can be configured between an AP MLD and a non-AP MLD 1. If the frequency band interval between Link 1 and Link 3 is sufficient, the AP MLD can perform the STR operation using Link 1 and Link 3. In other words, the AP MLD can use Link 1 to transmit a frame and can use Link 3 to receive a frame. If the frequency band interval between Link 1 and Link 2 is insufficient, the AP MLD may not be able to perform the STR operation using Link 1 and Link 2. If the frequency band interval between Link 2 and Link 3 is insufficient, the AP MLD may not be able to perform the STR operation using Link 2 and Link 3.

[0062] On the other hand, in a wireless local area network system, a negotiation process for multi-link operation can be performed during the access process between a STA and an AP. A device that supports multi-link (e.g., an AP or a STA) can be referred to as a multi-link device (MLD). An AP that supports multi-link can be called an AP MLD, and a STA that supports multi-link can be called a non-AP MLD or a STA MLD. The AP MLD can have a physical address (e.g., a MAC address) for each link. The AP MLD can be implemented as if there were separate APs responsible for each link. Multiple APs can be managed within one AP MLD. Therefore, coordination between multiple APs belonging to the same AP MLD is possible. The STA MLD can have a physical address (e.g., a MAC address) for each link. The STA MLD can be implemented as if there were separate STAs responsible for each link. Multiple STAs can be managed within one STA MLD. Therefore, coordination between multiple STAs belonging to the same STA MLD is possible.

[0063] For example, AP 1 of the AP MLD and STA 1 of the STA MLD can each be responsible for the first link and can communicate using the first link. AP 2 of the AP MLD and STA 2 of the STA MLD can each be responsible for the second link and can communicate using the second link. STA 2 can receive status change information for the first link on the second link. In this case, the STA MLD can collect information (e.g., status change information) received from each link and can control the operations performed by STA 1 based on the collected information.

[0064] Next, a method of transmitting and receiving data in a wireless local area network system will be described. When describing a method (e.g., signal transmission or reception) performed by a first communication node in a communication node, a corresponding second communication node can perform a method corresponding to the method performed by the first communication node (e.g., signal reception or transmission). In other words, when describing the operation of a STA, the corresponding AP can perform an operation corresponding to the operation of the STA. On the other hand, when describing the operation of an AP, the corresponding STA can perform an operation corresponding to the operation of the AP.

[0065] In the present invention, the operation of the STA can be interpreted as the operation of the STA MLD, and the operation of the STA MLD can be interpreted as the operation of the STA. The operation of the AP can 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. The STA of the STA MLD can represent the STA connected to the STA MLD, and the AP of the AP MLD can represent the AP connected to the AP MLD. When the STA MLD includes a first STA operating on a first link and a second STA operating on a second link, the operation of the STA MLD on the first link can be interpreted as the operation of the first STA, and the operation of the STA MLD on the second link can be interpreted as the operation of the second STA. When the AP MLD includes a first AP operating on a first link and a second AP operating on a second link, the operation of the AP MLD on the first link can be interpreted as the operation of the first AP, and the operation of the AP MLD on the second link can be interpreted as the operation of the second AP.

[0066] In the present invention, a wireless local area network can support multi-link single radio (MLSR) operation and / or enhanced multi-link single radio (EMLSR) operation. The MLSR operation and the EMLSR operation can be used with the same meaning. For example, the EMLSR operation supported in the present invention can be applied to a wireless local area network that supports the MLSR operation. The MLSR operation supported in the present invention can be applied to a wireless local area network that supports the EMLSR operation. The MLD that supports the EMLSR operation can be an EMLSR MLD, an EMLSR AP MLD, and / or an EMLSR STA MLD. The EMLSR AP can be an AP that supports the EMLSR operation. The EMLSR STA can be a STA that supports the EMLSR operation. The EMLSR MLD, the EMLSR AP MLD, the EMLSR STA MLD, the EMLSR AP, and / or the EMLSR STA can support the EMLSR operation and / or the MLSR operation.

[0067] Figure 3 is a timing diagram showing a first embodiment of a communication method of an EMLSR STA.

[0068] Reference Figure 3, a wireless local area network can support multi-link operation. AP MLD 1 and / or STA MLD 1 can operate on multiple links (e.g., a first link and a second link). An AP connected to AP MLD 1 operating on the first link can be referred to as AP 1. An AP connected to AP MLD 1 operating on the second link can be referred to as AP 2. A STA connected to STA MLD 1 operating on the first link can be referred to as STA 1. A STA connected to STA MLD 1 operating on the second link can be referred to as STA 2. STA MLD 1 can support EMLSR operation (e.g., MLSR operation). In other words, STA MLD 1 can be an EMLSR STA MLD (e.g., MLSR STA MLD). STA MLD 1 can perform EMLSR operation on multiple links (e.g., a first link and a second link). A STA connected to STA MLD 1 on each link can be referred to as an EMLSR STA. The STA 1 operating on the first link can be referred to as EMLSR STA 1, and the STA 2 operating on the second link can be referred to as EMLSR STA 2.

[0069] The EMLSR STA MLD can initiate or terminate EMLSR operation (or EMLSR mode) by exchanging enhanced multi-link (EML) operation mode notification (OMN) frames with the AP MLD. Before initiating or terminating the EMLSR mode, one of the STAs, STA 1 or STA 2, can perform normal transmit / receive operations and / or listening operations using a transceiver (e.g., a radio) at a preset time. STA 1 and STA 2 may not be able to perform normal transmit / receive operations simultaneously.

[0070] When the EMLSR STA MLD initiates the EMLSR mode by exchanging EML OMN frames, the EMLSR STA MLD can operate in the EMLSR mode on an EMLSR link negotiated between the EMLSR STA MLD and the AP MLD. In other words, the EMLSR STA MLD can perform EMLSR operation on the EMLSR link. In the EMLSR mode, the EMLSR STA MLD (e.g., EMLSR STA) can perform listening operations or normal transmit / receive operations. The EMLSR STA MLD can perform listening operations to receive frames with a predefined format (e.g., initial control frames) on the EMLSR link.

[0071] When receiving an initial control frame, the EMLSR STA MLD may transition all receive radios (e.g., all receive antennas) or all transmit / receive radios (e.g., all transmit / receive antennas) operating on links other than the link on which the initial control frame is received to the link on which the initial control frame is received, and perform normal transmit / receive operations on the link on which the initial control frame is received. In other words, the EMLSR STA MLD may transmit / receive frames with the AP MLD on the link on which the initial control frame is received. When the EMLSR STA MLD wishes to transmit a frame to the AP MLD, the EMLSR STA MLD may transition all radios to one of the EMLSR links and transmit the frame to the AP MLD by using the radios on one link (e.g., all radios).

[0072] STA 1 may perform normal transmit / receive operations and listening operations. The state of performing normal transmit / receive operations may be referred to as the normal transmit / receive state. The state of performing listening operations may be referred to as the listening state. When performing normal transmit / receive operations, STA 1 may perform transmit / receive operations on all frames. In other words, STA 1 operating in the normal transmit / receive state may perform communication on one link (e.g., the first link). When performing listening operations, STA 1 may only receive frames with a predefined format. In other words, STA 1 operating in the listening state may perform a listening operation to receive frames on the EMLSR link. The frames with a predefined format may be initial control frames. The initial control frame may be a multi-user (MU)-request to send (RTS) frame or a buffer status report poll (BSRP) trigger frame.

[0073] When the operating state of STA 1 is the listening state, STA 2 connected to EMLSR STA MLD 1 can perform the listening operation. When the operating state of STA 1 is the normal transmit / receive state, the operating state of STA 2 connected to EMLSR STA MLD 1 can be the non-transmit / receive state. In the non-transmit / receive state, STA 2 may not be able to transmit / receive frames. When STA 1 changes from the listening state to the normal transmit / receive state, STA 2 can be in the non-transmit / receive state. During the time required to change from the normal transmit / receive state to the listening state (e.g., Tt time), STA 2 can be in the non-transmit / receive state. The change of the operating state can be similarly applied to STA 1 and STA 2 (e.g., STAs connected to the same EMLSR STA MLD). For example, if STA 2 is in the listening state, STA 1 can be in the listening state. If STA 2 is in the normal transmit / receive state, STA 1 can be in the non-transmit / receive state.

[0074] On the first link, AP 1 can configure (e.g., obtain, initiate) the TXOP before performing the transmit opportunity (TXOP) sharing operation. The TXOP can be configured (e.g., obtained, initiated) when "AP 1 performs the process of exchanging the request to send (RTS) frame and the clear to send (CTS) frame", "AP 1 sends the CTS-to-self frame", and / or "AP 1 sends the data frame". As another method, AP 1 can configure the TXOP by performing "the operation of sending the TXOP sharing (TXS) operation" and / or "the operation of sending the initial control frame (e.g., MU-RTS frame, MU-RTS trigger frame, MU-RTS TXS frame) and receiving the CTS frame".

[0075] Within the TXOP configured on the first link, AP 1 can send a MU-RTS frame to STA 1 (e.g., an EMLSR STA) without performing a channel contention process. The MU-RTS frame can be the initial control frame for EMLSR operation. The MU-RTS frame can be a frame indicating TXOP sharing operation (e.g., a MU-RTS TXS frame). The difference between the MU-RTS TXS frame and the MU-RTS frame for the initial control frame (ICF) can be the value of the TXOP sharing mode subfield triggered included in the common information field. For example, the value of the TXOP sharing mode subfield triggered included in the MU-RTS TXS frame can be set to indicate TXOP sharing, and the value of the TXOP sharing mode subfield triggered included in the MU-RTS frame for the ICF can be set to a value that does not indicate TXOP sharing.

[0076] The receiver of the MU-RTS frame for the ICF and the MU-RTS TXS frame can be a STA. Information about the STA as the receiver can be indicated by the user information field included in the MU-RTS frame and the MU-RTS TXS frame. The TXOP sharing operation can be a triggered TXOP sharing operation. For example, AP 1 can share a part or all of the TXOP with STA 1. The TXOP sharing mode can be set to 1. In this case, the receiver of the frame sent by STA 1 in the shared TXOP can be AP 1. In other words, "when AP 1 shares the TXOP with STA 1 and the TXOP sharing mode is indicated as 1", STA 1 can send a frame (e.g., a data frame) to AP 1 sharing the TXOP and receive a frame (e.g., a data frame) from AP 1 sharing the TXOP within the shared TXOP. Therefore, the operation according to TXOP sharing mode 1 can be "the operation of STA 1 sending a data frame to AP 1". STA 1 can perform an uplink transmission to the AP within the shared TXOP.

[0077] The EMLSR STA operating in the EMLSR mode can receive the initial control frame during the listening operation. In this case, in order to perform normal send / receive operations on the link where the initial control frame is received, the EMLSR STA can change the receiving radio from a link other than the link where the initial control frame is received to the link where the initial control frame is received. The time required to change the receiving radio can be time Tt. The time required to change from the normal send / receive state to the listening state can be time Tt. Time Tt can be the EMLSR transition delay or the EMLSR fill delay.

[0078] The MU-RTS frame as an initial control frame can indicate TXOP sharing. The length of the padding included in the MU-RTS frame should be longer than the length corresponding to time Tt, where time Tt is the time required for the operation state of the EMLSR STA to change from the listening state to the normal transmission / reception state. Therefore, in order to make the length of the padding included in the MU-RTS frame equal to or longer than the length corresponding to time Tt, the MU-RTS frame can include padding bits (e.g., padding bits). The padding bits can be bits used to increase the time length of the frame. STA 1 can receive the MU-RTS frame from AP 1. When receiving the MU-RTS frame of AP 1, STA1 can change the operation state from the listening state to the normal transmission / reception state.

[0079] STA 1 can decode the MU-RTS frame of AP 1 and confirm that AP 1 performs TXOP sharing based on the decoding result (e.g., the information element (e.g., field) included in the MU-RTS frame). For example, STA 1 can identify the time indicated by the allocated duration subfield of the MU-RTS frame and identify the TXOP length shared by AP 1 based on the identified time. The shared TXOP length or / and the shared TXOP can be referred to as the time allocated by the MU-RTS TXS trigger frame. STA 1 can send a CTS frame to AP 1 after a short interframe space (SIFS) from the reception time (e.g., the reception end time) of the MU-RTS frame of AP 1. STA 1 can confirm that medium access control (MAC) primitives and / or physical primitives occur during time Tw from the transmission time (e.g., the transmission end time) of the CTS frame. MAC primitives can occur at the MAC layer. PHY primitives can occur at the PHY layer. The operation of STA 1 based on the primitives (e.g., MAC primitives and / or PHY primitives) that occur during time Tw can be performed based on the following conditions. Time Tw can be aSIFSTime + aSlotTime + aRxPHYStartDelay.

[0080] If one or more of the following conditions are satisfied during time Tw, STA 1 may not change the operation state from the normal transmission / reception state to the listening state.

[0081] - Condition 1: The PHY-RXSTART.indication primitive appears in the PHY layer of STA 1.

[0082] - Condition 2: The MAC layer of STA 1 passes the PHY-RXSTART.indication primitive to the PHY layer of STA 1, and the PHY layer passes the PHY-TXSTART.confirm primitive to the MAC layer as a response to a request (e.g., the PHY-TXSTART.request primitive).

[0083] If neither Condition 1 nor Condition 2 is satisfied, STA 1 can change its operation state from the normal transmission / reception state to the listening state. Each of Condition 1 and Condition 2 can be a state maintenance condition (or a state transition condition). If the state maintenance condition (e.g., at least one state maintenance condition) is satisfied within a preset time (e.g., time Tw), STA 1 can maintain its current operation state (e.g., the normal transmission / reception state). If the state maintenance condition (e.g., all state maintenance conditions) is not satisfied within a preset time (e.g., time Tw), STA 1 can change its current operation state. In this document, STA 1 can change its operation state from the normal transmission / reception state to the listening state. Condition 1 can represent "the condition for STA 1 to receive a frame from another communication node (e.g., AP 1 or another STA)". Condition 2 can represent "the condition that a frame to be transmitted to another communication node (e.g., AP 1 or another STA) appears at STA 1".

[0084] Since the TXOP of AP 1 is shared with STA 1, STA 1 can send a frame to AP 1 within the SIFS or the point coordination function (PCF) interframe space (PIFS) starting from the transmission time of the CTS frame. Within the shared TXOP, STA 1 can be the TXOP holder or the TXOP owner. The SIFS or PIFS can be a time shorter than time Tw. STA 1 can send a frame (e.g., a data frame) to AP 1 and receive a response frame to that frame from AP 1. In the present invention, the response frame can represent an acknowledgment (ACK) frame or a block ACK (BA) frame.

[0085] STA 1 can wait for a time Tw that starts from the time when it receives an ACK frame from AP 1. In other words, STA 1 can determine whether the status holding condition is satisfied within the time Tw. A frame to be sent to AP 1 (e.g., a data frame) may not exist in STA 1. Therefore, the MAC layer of STA 1 may not pass the PHY-TXSTART.request primitive to the PHY layer of STA 1 within the time Tw. In this case, the PHY layer of STA 1 may not pass the PHY-TXSTART.confirm primitive (which is a response to the PHY-TXSTART.request primitive) to the MAC layer of STA 1. A frame to be sent to STA 1 (e.g., data) may not exist in AP 1. Therefore, AP 1 may not send any frame to STA 1, and STA 1 may not receive any frame from AP 1. When no frame is received, the PHY layer of STA 1 may not generate the PHY-RXSTART.indication primitive. In other words, when no frame is received, the PHY-RXSTART.indication primitive may not appear in the PHY layer of STA 1 within the time Tw. If neither condition 1 nor condition 2 is satisfied, STA 1 may operate in the listening state after the time Tw. In other words, the operating state of STA 1 may change from the normal transmission / reception state to the listening state after the time Tw.

[0086] As another approach, in the shared TXOP indicated by the MU-RTS frame of AP 1, STA 1 may not transition its operation state from the normal transmit / receive state to the listening state. In other words, the operation state of STA 1 may remain in the normal transmit / receive state within the shared TXOP (e.g., within the time allocated by the MU-RTS TXS frame). After the end time of the shared TXOP, STA 1 may transition its operation state from the normal transmit / receive state to the listening state. For example, when AP1 shares a TXOP with STA 1, STA 1 may operate as the TXOP owner within the shared TXOP. Alternatively, STA 1 may operate similarly to the TXOP owner within the shared TXOP. In other words, just as STA 1 obtains a TXOP, STA 1 may operate in the EMLSR mode within the shared TXOP. "STA 1 operates in the EMLSR mode" may mean "STA 1 does not return to the listening state". In other words, "STA 1 operates in the EMLSR mode" may mean "STA 1 operates in a state where it can send and receive frames (i.e., the normal transmit / receive state)". When STA 1, which is connected to the EMLSR STA MLD 1, obtains a TXOP, STA 1 may perform normal transmit / receive operations within the TXOP. In other words, STA 1 may send / receive frames within the TXOP.

[0087] For example, STA 1 can receive a MU-RTS TXS frame from AP 1 and send a CTS frame to AP 1 as a response to the MU-RTS TXS frame. In this case, the TXOP of AP 1 can be shared with STA 1. STA 1 can consider obtaining its own TXOP within the shared TXOP (e.g., the time allocated by the MU-RTS TXS frame). STA 1 can operate as a TXOP owner within the shared TXOP. Alternatively, STA 1 can operate similarly to a TXOP owner within the shared TXOP. STA 1 can perform normal transmission / reception operations within the shared TXOP. STA 1 can send a frame to AP 1 within the shared TXOP. When the shared TXOP ends (e.g., expires, is interrupted), STA 1 can transition its operation state from the normal transmission / reception state to the listening state. The time required for STA 1 to transition its operation state from the normal transmission / reception state to the listening state can be time Tt (e.g., EMLSR transition delay time, EMLSR padding delay time). STA 1 can send a frame indicating an interruption of the shared TXOP midway. In this frame, the RDG / More PPDU subfield of the command and status (CAS) field in the A control field included in the MAC header can be set to 0, and the recipient of the frame can be AP 1. In other words, the shared TXOP can be terminated midway. STA 1 can transition its operation state to the listening state within time Tt after the time of receiving a frame (e.g., BA frame) as a response to the frame sent to AP 1. As another method, STA 1 may not need to receive a frame as a response to the frame sent to AP 1. In this case, STA 1 can transition its operation state from the normal transmission / reception state to the listening state after time Tt (EMLSR transition delay time, EMLSR padding delay time) from the frame transmission time (e.g., transmission end time).

[0088] AP MLD 1 can send a TXS frame and / or an initial control frame (e.g., MU-RTS frame, MU-RTS trigger frame, MU-RTS TXS frame) to STA 1 of STA MLD 1. Then, AP MLD 1 can send an initial control frame to STA 2 of STA MLD 1 without using the EMLSR link (e.g., the second link) within the shared TXOP indicated by the MU-RTS frame.

[0089] Figure 4 is a timing diagram showing a second embodiment of the communication method of the EMLSR STA.

[0090] Reference Figure 4, a wireless local area network can support multi-link operation. AP MLD 1 and / or STA MLD 1 can operate on multiple links (e.g., the first link and the second link). The AP connected to AP MLD 1 operating on the first link can be referred to as AP 1. The AP connected to AP MLD 1 operating on the second link can be referred to as AP 2. The STA connected to STA MLD 1 operating on the first link can be referred to as STA 1. The STA connected to STA MLD 1 operating on the second link can be referred to as STA 2. STA MLD 1 can support EMLSR operation (e.g., MLSR operation). In other words, STA MLD 1 can be an EMLSR STA MLD (e.g., MLSR STA MLD). STA MLD 1 can perform EMLSR operation on multiple links (e.g., the first link and the second link). The STA connected to STA MLD 1 on each link can be referred to as an EMLSR STA. The STA 1 operating on the first link can be referred to as EMLSR STA 1, and the STA 2 operating on the second link can be referred to as EMLSR STA 2.

[0091] The EMLSR STA MLD can initiate or terminate the EMLSR operation (or EMLSR mode) by exchanging enhanced multi-link (EML) operation mode notification (OMN) frames with the AP MLD. Before initiating or terminating the EMLSR mode, one of the STAs of STA 1 or STA 2 can perform normal transmission / reception operations and / or listening operations by using a transceiver (e.g., a radio) at a preset time. STA 1 and STA 2 may not be able to perform normal transmission / reception operations simultaneously.

[0092] When the EMLSR STA MLD initiates the EMLSR mode by exchanging EML OMN frames, the EMLSR STA MLD can operate in the EMLSR mode on the EMLSR link negotiated between the EMLSR STA MLD and the AP MLD. In other words, the EMLSR STA MLD can perform EMLSR operation on the EMLSR link. In the EMLSR mode, the EMLSR STA MLD (e.g., EMLSR STA) can perform listening operations or normal transmission / reception operations. The EMLSR STA MLD can perform listening operations to receive frames with a predefined format (e.g., initial control frames) on the EMLSR link.

[0093] When receiving an initial control frame, the EMLSR STA MLD can transition all receive radios (e.g., all receive antennas) or all transmit / receive radios (e.g., all transmit / receive antennas) operating on links other than the link on which the initial control frame is received to the link on which the initial control frame is received, and perform normal transmit / receive operations on the link on which the initial control frame is received. In other words, the EMLSR STA MLD can transmit / receive frames with the AP MLD on the link on which the initial control frame is received. When the EMLSR STA MLD wishes to transmit a frame to the AP MLD, the EMLSR STA MLD can transition all radios to one of the EMLSR links and transmit the frame to the AP MLD by using the radios on one link (e.g., all radios).

[0094] STA 1 can perform normal transmit / receive operations and listening operations. The state of performing normal transmit / receive operations can be referred to as the normal transmit / receive state. The state of performing listening operations can be referred to as the listening state. When performing normal transmit / receive operations, STA 1 can perform transmit / receive operations on all frames. In other words, STA 1 operating in the normal transmit / receive state can communicate on one link (e.g., the first link). When performing listening operations, STA 1 can only receive frames with a predefined format. In other words, STA 1 operating in the listening state can perform listening operations to receive frames on the EMLSR link. Frames with a predefined format can be initial control frames. Initial control frames can be MU-RTS frames or BSRP trigger frames.

[0095] When the operating state of STA 1 is the listening state, STA 2 connected to the EMLSR STA MLD 1 can perform listening operations. When the operating state of STA 1 is the normal transmit / receive state, the operating state of STA 2 connected to the EMLSR STA MLD 1 can be a state where it cannot transmit / receive. In the state where it cannot transmit / receive, STA 2 may not be able to transmit / receive frames. When STA 1 transitions from the listening state to the normal transmit / receive state, STA 2 can be in the state where it cannot transmit / receive. Within the time required to transition from the normal transmit / receive state to the listening state (e.g., the Tt time), STA 2 can be in the state where it cannot transmit / receive. The change in the operating state can be similarly applied to STA 1 and STA 2 (e.g., STAs connected to the same EMLSR STA MLD). For example, if STA 2 is in the listening state, STA 1 can be in the listening state. If STA 2 is in the normal transmit / receive state, STA 1 can be in the state where it cannot transmit / receive.

[0096] On the first link, AP 1 may configure (e.g., obtain, initiate) a TXOP before performing a transmit opportunity (TXOP) sharing operation. The TXOP may be configured (e.g., obtained, initiated) when "AP 1 performs the process of exchanging a request to send (RTS) frame and a clear to send (CTS) frame", "AP 1 sends a CTS-to-self frame", and / or "AP 1 sends a data frame". As another method, AP 1 may configure the TXOP by performing "the operation of sending a TXOP sharing (TXS) operation" and / or "the operation of sending an initial control frame (e.g., a multi-user RTS (MU-RTS) frame, a MU-RTS trigger frame, a MU-RTS TXS frame) and receiving a CTS frame".

[0097] Within the TXOP configured on the first link, AP 1 may send a MU-RTS frame to STA 1 (e.g., an EMLSR STA) without performing a channel contention process. The MU-RTS frame may be an initial control frame for EMLSR operation. The MU-RTS frame may be a frame indicating a TXOP sharing operation (e.g., a MU-RTS TXS frame). The difference between the MU-RTS TXS frame and the MU-RTS frame for an initial control frame (ICF) may be the value of a TXOP sharing mode subfield triggered included in a common information field. For example, the value of the TXOP sharing mode subfield triggered included in the MU-RTS TXS frame may be set to a value indicating TXOP sharing, and the value of the TXOP sharing mode subfield triggered included in the MU-RTS frame for the ICF may be set to a value not indicating TXOP sharing.

[0098] The receiver of the MU-RTS frame for the ICF and the MU-RTS TXS frame may be a single STA. Information about the STA as the receiver may be indicated by a user information field included in the MU-RTS frame and the MU-RTS TXS frame. The TXOP sharing operation may be a triggered TXOP sharing operation. For example, AP 1 may share a part or all of the TXOP with STA 1. The TXOP sharing mode may be set to 1. In this case, the receiver of the frame sent by STA 1 in the shared TXOP may be AP 1. In other words, "when AP 1 shares the TXOP with STA 1 and the TXOP sharing mode is indicated as 1", STA 1 may send a frame (e.g., a data frame) to AP 1 sharing the TXOP and receive a frame (e.g., a data frame) from AP 1 sharing the TXOP within the shared TXOP. Therefore, the operation according to TXOP sharing mode 1 may be "the operation of STA 1 sending a data frame to AP 1". STA 1 may perform an uplink transmission to the AP within the shared TXOP.

[0099] An EMLSR STA operating in the EMLSR mode can receive an initial control frame during the listening operation. In this case, in order to perform normal transmission / reception operations on the link where the initial control frame is received, the EMLSR STA can switch the receiving radio from a link other than the link where the initial control frame is received to the link where the initial control frame is received. The time required to switch the receiving radio can be time Tt. The time required to switch from the normal transmission / reception state to the listening state can be time Tt. Time Tt can be the EMLSR transition delay or the EMLSR padding delay.

[0100] The MU-RTS frame as the initial control frame can indicate TXOP sharing. The length of the padding included in the MU-RTS frame should be longer than the length corresponding to time Tt, where time Tt is the time required for the operating state of the EMLSR STA to switch from the listening state to the normal transmission / reception state. Therefore, in order to make the length of the padding included in the MU-RTS frame equal to or longer than the length corresponding to time Tt, the MU-RTS frame can include padding bits (e.g., padding bits). The padding bits can be bits used to increase the time length of the frame. STA 1 can receive the MU-RTS frame from AP 1. When receiving the MU-RTS frame of AP 1, STA1 can switch the operating state from the listening state to the normal transmission / reception state.

[0101] STA 1 can decode the MU-RTS frame of AP 1 and confirm that AP 1 performs TXOP sharing based on the decoding result (e.g., the information element (e.g., field) included in the MU-RTS frame). For example, STA 1 can identify the time indicated by the allocation duration subfield of the MU-RTS frame and identify the TXOP length shared by AP 1 based on the identified time. The shared TXOP length or / and the shared TXOP can be referred to as the time allocated by the MU-RTS TXS trigger frame. STA 1 can send a CTS frame to AP 1 after a short interframe space (SIFS) from the reception time (e.g., the reception end time) of the MU-RTS frame of AP 1. STA 1 can confirm that medium access control (MAC) primitives and / or PHY primitives occur during time Tw from the transmission time (e.g., the transmission end time) of the CTS frame. The operation of STA 1 based on the primitives (e.g., MAC primitives and / or PHY primitives) that occur during time Tw can be performed based on the following conditions. Time Tw can be aSIFSTime + aSlotTime + aRxPHYStartDelay.

[0102] If one or more of the following conditions are satisfied during the Tw time, the STA 1 may not change the operation state from the normal transmission / reception state to the listening state.

[0103] - Condition 1: The PHY-RXSTART.indication primitive appears at the PHY layer of the STA 1.

[0104] - Condition 2: The MAC layer of the STA 1 passes the PHY-RXSTART.indication primitive to the PHY layer of the STA 1, and the PHY layer passes the PHY-TXSTART.confirm primitive to the MAC layer as a response to a request (e.g., the PHY-TXSTART.request primitive).

[0105] If neither Condition 1 nor Condition 2 is satisfied, the STA 1 may change the operation state from the normal transmission / reception state to the listening state. Each of Condition 1 and Condition 2 may be a state retention condition (or a state transition condition). If the state retention condition (e.g., at least one state retention condition) is satisfied within a preset time (e.g., time Tw), the STA 1 may maintain the current operation state (e.g., the normal transmission / reception state). If the state retention condition (e.g., all state retention conditions) is not satisfied within a preset time (e.g., time Tw), the STA 1 may change the current operation state. In this document, the STA 1 may change the operation state from the normal transmission / reception state to the listening state. Condition 1 may represent "the condition for the STA 1 to receive a frame from another communication node (e.g., AP 1 or another STA)". Condition 2 may represent "the condition for a frame to be sent to another communication node (e.g., AP 1 or another STA) to appear at the STA 1".

[0106] Since the TXOP of the AP 1 is shared with the STA 1, the STA 1 may send a frame to the AP 1 within SIFS or PIFS from the transmission time of the CTS frame. Within the shared TXOP, the STA 1 may be the TXOP holder or the TXOP owner. SIFS or PIFS may be a time shorter than the time Tw. The STA 1 may send a frame to the AP 1 and receive a response frame to the frame from the AP 1. In the present invention, the response frame may represent an ACK frame or a BA frame.

[0107] STA 1 can wait for a time Tw starting from the time when it receives the ACK frame from AP 1. In other words, STA 1 can determine whether the status holding condition is satisfied within the time Tw. A frame (e.g., data) to be sent to AP 1 may exist in STA 1. Therefore, the MAC layer of STA 1 can pass the PHY-TXSTART.request primitive to the PHY layer of STA 1 within the time Tw. In this case, the PHY layer of STA 1 can receive the PHY-TXSTART.request primitive from the MAC layer of STA 1 and pass the PHY-TXSTART.confirm primitive to the MAC layer of STA 1 as a response to the PHY-TXSTART.request primitive. In this case, condition 2 can be satisfied, and STA 1 can not change the operation state from the normal transmission / reception state to the listening state after the time Tw.

[0108] STA 1 can send a frame to AP 1 after the SIFS from the reception time (e.g., the reception end time) of the ACK frame of AP 1. STA 1 can receive a response frame (e.g., ACK frame, BA frame) for this frame from AP 1. STA 1 can wait for a time Tw starting from the time when it receives the response frame from AP 1. In other words, STA 1 can determine whether the status holding condition is satisfied within the time Tw. A frame (e.g., data) to be sent to AP 1 may not exist in STA 1. Therefore, the MAC layer of STA 1 can not pass the PHY-TXSTART.request primitive to the PHY layer of STA 1 within the time Tw. In this case, the PHY layer of STA 1 can not pass the PHY-TXSTART.confirm primitive as a response to the PHY-TXSTART.request primitive to the MAC layer of STA 1.

[0109] A frame (e.g., data) to be sent to STA 1 may not exist in AP 1. Therefore, AP 1 can not send any frame to STA 1, and STA 1 can not receive any frame from AP 1. When no frame is received, the PHY layer of STA 1 can not generate the PHY-RXSTART.indication primitive. In other words, when no frame is received, the PHY-RXSTART.indication primitive can not appear in the PHY layer of STA 1 within the time Tw. If neither condition 1 nor condition 2 is satisfied, STA 1 can operate in the listening state after the time Tw. In other words, the operation state of STA 1 can change from the normal transmission / reception state to the listening state after the time Tw.

[0110] As another approach, in the shared TXOP indicated by the MU-RTS frame of AP 1, STA 1 may not transition its operation state from the normal transmit / receive state to the listening state. In other words, the operation state of STA 1 may remain in the normal transmit / receive state within the shared TXOP (e.g., within the time allocated by the MU-RTS TXS frame). After the end time of the shared TXOP, STA 1 may transition its operation state from the normal transmit / receive state to the listening state. For example, when AP1 shares a TXOP with STA 1, STA 1 may operate as the TXOP owner within the shared TXOP. Alternatively, STA 1 may operate similarly to the TXOP owner within the shared TXOP. In other words, just as STA 1 acquires a TXOP, STA 1 may operate in the EMLSR mode within the shared TXOP. "STA 1 operates in the EMLSR mode" may mean "STA 1 does not return to the listening state". In other words, "STA 1 operates in the EMLSR mode" may mean "STA 1 operates in a state where it can transmit and receive frames (i.e., the normal transmit / receive state)". When STA 1, which is connected to the EMLSR STA MLD 1, acquires a TXOP, STA 1 may perform normal transmit / receive operations within the TXOP. In other words, STA 1 may transmit / receive frames within the TXOP.

[0111] For example, STA 1 can receive a MU-RTS TXS frame from AP 1 and send a CTS frame to AP 1 as a response to the MU-RTS TXS frame. In this case, the TXOP of AP 1 can be shared with STA 1. STA 1 can consider obtaining its own TXOP within the shared TXOP (e.g., the time allocated by the MU-RTS TXS frame). STA 1 can operate as the TXOP owner within the shared TXOP. Alternatively, STA 1 can operate similarly to the TXOP owner within the shared TXOP. STA 1 can perform normal transmission / reception operations within the shared TXOP. STA 1 can send a frame to AP 1 within the shared TXOP. When the shared TXOP ends (e.g., expires, is interrupted), STA 1 can transition its operation state from the normal transmission / reception state to the listening state. The time required for STA 1 to transition its operation state from the normal transmission / reception state to the listening state can be time Tt (e.g., EMLSR transition delay time, EMLSR padding delay time). STA 1 can send a frame indicating an interrupted shared TXOP to AP 1. In this frame, the RDG / More PPDU subfield of the Command and Status (CAS) field of the A control field included in the MAC header can be set to 0. The recipient of this frame can be AP 1. In other words, the shared TXOP can be terminated midway. STA 1 can transition its operation state to the listening state within time Tt after the time of receiving a frame (e.g., BA frame) as a response to the frame sent to AP 1. As another method, STA 1 may not have to receive a frame as a response to the frame sent to AP 1. In this case, STA 1 can transition its operation state from the normal transmission / reception state to the listening state after time Tt (EMLSR transition delay time, EMLSR padding delay time) from the frame transmission time (e.g., transmission end time).

[0112] AP MLD 1 can send a TXS frame and / or an initial control frame (e.g., MU-RTS frame, MU-RTS trigger frame, MU-RTS TXS frame) to STA 1 of STA MLD 1. Then, AP MLD 1 can send an initial control frame to STA 2 of STA MLD 1 without using the EMLSR link (e.g., the second link) within the shared TXOP indicated by the MU-RTS frame.

[0113] Figure 5 is a timing diagram showing a third embodiment of the communication method of the EMLSR STA.

[0114] Reference Figure 5, a wireless local area network can support multi-link operation. AP MLD 1 and / or STA MLD 1 can operate on multiple links (e.g., a first link and a second link). An AP connected to AP MLD 1 operating on the first link can be referred to as AP 1. An AP connected to AP MLD 1 operating on the second link can be referred to as AP 2. A STA connected to STA MLD 1 operating on the first link can be referred to as STA 1. A STA connected to STA MLD 1 operating on the second link can be referred to as STA 2. STA MLD 1 can support EMLSR operation (e.g., MLSR operation). In other words, STA MLD 1 can be an EMLSR STA MLD (e.g., an MLSR STA MLD). STA MLD 1 can perform EMLSR operations on multiple links (e.g., a first link and a second link). A STA connected to STA MLD 1 on each link can be referred to as an EMLSR STA. STA 1 operating on the first link can be referred to as EMLSR STA 1, and STA 2 operating on the second link can be referred to as EMLSR STA 2.

[0115] An EMLSR STA MLD can initiate or terminate an EMLSR operation (or EMLSR mode) by exchanging Enhanced Multi-Link (EML) Operation Mode Notification (OMN) frames with an AP MLD. Before initiating or terminating the EMLSR mode, one of STA 1 or STA 2 can perform normal transmit / receive operations and / or listening operations using a transceiver (e.g., a radio) at a preset time. STA 1 and STA 2 may not be able to perform normal transmit / receive operations simultaneously.

[0116] When an EMLSR STA MLD initiates the EMLSR mode by exchanging EML OMN frames, the EMLSR STA MLD can operate in the EMLSR mode on an EMLSR link negotiated between the EMLSR STA MLD and the AP MLD. In other words, the EMLSR STA MLD can perform EMLSR operations on the EMLSR link. In the EMLSR mode, the EMLSR STA MLD (e.g., an EMLSR STA) can perform listening operations or normal transmit / receive operations. The EMLSR STA MLD can perform listening operations to receive frames with a predefined format (e.g., an initial control frame) on the EMLSR link.

[0117] When receiving an initial control frame, the EMLSR STA MLD can transition all receive radios (e.g., all receive antennas) or all transmit / receive radios (e.g., all transmit / receive antennas) operating on links other than the link on which the initial control frame is received to the link on which the initial control frame is received, and perform normal transmit / receive operations on the link on which the initial control frame is received. In other words, the EMLSR STA MLD can transmit / receive frames with the AP MLD on the link on which the initial control frame is received. When the EMLSR STA MLD wishes to transmit a frame to the AP MLD, the EMLSR STA MLD can transition all radios to one of the EMLSR links and transmit the frame to the AP MLD by using the radios on one link (e.g., all radios).

[0118] STA 1 can perform normal transmit / receive operations and listening operations. The state of performing normal transmit / receive operations can be referred to as the normal transmit / receive state. The state of performing the listening operation can be referred to as the listening state. When performing normal transmit / receive operations, STA 1 can perform transmit / receive operations on all frames. In other words, STA 1 operating in the normal transmit / receive state can communicate on one link (e.g., the first link). When performing the listening operation, STA 1 can only receive frames with a predefined format. In other words, STA 1 operating in the listening state can perform a listening operation to receive frames on the EMLSR link. The frame with a predefined format can be an initial control frame. The initial control frame can be a MU-RTS frame or a BSRP trigger frame.

[0119] When the operating state of STA 1 is the listening state, STA 2 connected to the EMLSR STA MLD 1 can perform the listening operation. When the operating state of STA 1 is the normal transmit / receive state, the operating state of STA 2 connected to the EMLSR STA MLD 1 can be a state where it cannot transmit / receive. In the state where it cannot transmit / receive, STA 2 may not be able to transmit / receive frames. When STA 1 transitions from the listening state to the normal transmit / receive state, STA 2 can be in the state where it cannot transmit / receive. During the time required to transition from the normal transmit / receive state to the listening state (e.g., the Tt time), STA 2 can be in the state where it cannot transmit / receive. The change in the operating state can be similarly applied to STA 1 and STA 2 (e.g., STAs connected to the same EMLSR STA MLD). For example, if STA 2 is in the listening state, STA 1 can be in the listening state. If STA 2 is in the normal transmit / receive state, STA 1 can be in the state where it cannot transmit / receive.

[0120] On the first link, AP 1 may configure (e.g., obtain, initiate) a TXOP before performing a transmit opportunity (TXOP) sharing operation. When "AP 1 performs the process of exchanging a request to send (RTS) frame and a clear to send (CTS) frame", "AP 1 sends a CTS-to-self frame", and / or "AP 1 sends a data frame", a TXOP may be configured (e.g., obtained, initiated). As another method, AP 1 may configure a TXOP by performing "the operation of sending a TXOP sharing (TXS) operation" and / or "the operation of sending an initial control frame (e.g., a multi-user RTS (MU-RTS) frame, a MU-RTS trigger frame, a MU-RTS TXS frame) and receiving a CTS frame".

[0121] Within the TXOP configured on the first link, AP 1 may send a MU-RTS frame to STA 1 (e.g., an EMLSR STA) without performing a channel contention process. The MU-RTS frame may be an initial control frame for EMLSR operation. The MU-RTS frame may be a frame indicating a TXOP sharing operation (e.g., a MU-RTS TXS frame). The difference between the MU-RTS TXS frame and the MU-RTS frame for an initial control frame (ICF) may be the value of a TXOP sharing mode subfield triggered included in a common information field. For example, the value of the TXOP sharing mode subfield triggered included in the MU-RTS TXS frame may be set to indicate TXOP sharing, and the value of the TXOP sharing mode subfield triggered included in the MU-RTS frame for the ICF may be set to not indicate TXOP sharing.

[0122] The receiver of the MU-RTS frame for the ICF and the MU-RTS TXS frame may be a STA. Information about the STA as the receiver may be indicated by a user information field included in the MU-RTS frame and the MU-RTS TXS frame. The TXOP sharing operation may be a triggered TXOP sharing operation. For example, AP 1 may share a part or all of the TXOP with STA 1. The TXOP sharing mode may be set to 1. In this case, the receiver of the frame sent by STA 1 in the shared TXOP may be AP 1. In other words, "when AP 1 shares the TXOP with STA 1 and the TXOP sharing mode is indicated as 1", STA 1 may send a frame (e.g., a data frame) to AP 1 sharing the TXOP and receive a frame (e.g., a data frame) from AP 1 sharing the TXOP within the shared TXOP. Therefore, the operation according to TXOP sharing mode 1 may be "the operation of STA 1 sending a data frame to AP 1". STA 1 may perform an uplink transmission to the AP within the shared TXOP.

[0123] An EMLSR STA operating in the EMLSR mode can receive an initial control frame during the listening operation. In this case, in order to perform normal transmission / reception operations on the link where the initial control frame is received, the EMLSR STA can switch the receiving radio from a link other than the link where the initial control frame is received to the link where the initial control frame is received. The time required to switch the receiving radio can be time Tt. The time required to switch from the normal transmission / reception state to the listening state can be time Tt. Time Tt can be the EMLSR transition delay or the EMLSR padding delay.

[0124] The MU-RTS frame as the initial control frame can indicate TXOP sharing. The length of the padding included in the MU-RTS frame should be longer than the length corresponding to time Tt, where time Tt is the time required for the operation state of the EMLSR STA to switch from the listening state to the normal transmission / reception state. Therefore, in order to make the length of the padding included in the MU-RTS frame equal to or longer than the length corresponding to time Tt, the MU-RTS frame can include padding bits (e.g., padding bits). The padding bits can be bits used to increase the time length of the frame. STA 1 can receive the MU-RTS frame from AP 1. When receiving the MU-RTS frame of AP 1, STA1 can switch the operation state from the listening state to the normal transmission / reception state.

[0125] STA 1 can decode the MU-RTS frame of AP 1 and confirm that AP 1 performs TXOP sharing based on the decoding result (e.g., the information element (e.g., field) included in the MU-RTS frame). For example, STA 1 can identify the time indicated by the allocation duration subfield of the MU-RTS frame and identify the TXOP length shared by AP 1 based on the identified time. The shared TXOP length or / and the shared TXOP can be referred to as the time allocated by the MU-RTS TXS trigger frame. STA 1 can send a CTS frame to AP 1 after a short interframe space (SIFS) from the reception time (e.g., the reception end time) of the MU-RTS frame of AP 1. STA 1 can confirm that medium access control (MAC) primitives and / or PHY primitives occur during the time Tw from the transmission time (e.g., the transmission end time) of the CTS frame. The operation of STA 1 based on the primitives (e.g., MAC primitives and / or PHY primitives) occurring during time Tw can be performed based on the following conditions. Time Tw can be aSIFSTime + aSlotTime + aRxPHYStartDelay.

[0126] If one or more of the following conditions are satisfied during the Tw time, the STA 1 may not transition the operation state from the normal transmit / receive state to the listening state.

[0127] - Condition 1: The PHY-RXSTART.indication primitive appears at the PHY layer of the STA 1.

[0128] - Condition 2: The MAC layer of the STA 1 passes the PHY-RXSTART.indication primitive to the PHY layer of the STA 1, and the PHY layer passes the PHY-TXSTART.confirm primitive to the MAC layer as a response to a request (e.g., the PHY-TXSTART.request primitive).

[0129] If neither Condition 1 nor Condition 2 is satisfied, the STA 1 may transition the operation state from the normal transmit / receive state to the listening state. Each of Condition 1 and Condition 2 may be a state retention condition (or a state transition condition). If the state retention condition (e.g., at least one state retention condition) is satisfied within a preset time (e.g., time Tw), the STA 1 may maintain the current operation state (e.g., the normal transmit / receive state). If the state retention condition (e.g., all state retention conditions) is not satisfied within a preset time (e.g., time Tw), the STA 1 may transition the current operation state. In this document, the STA 1 may transition the operation state from the normal transmit / receive state to the listening state. Condition 1 may represent "the condition for the STA 1 to receive a frame from another communication node (e.g., AP 1 or another STA)". Condition 2 may represent "the condition for a frame to be sent to another communication node (e.g., AP 1 or another STA) to appear at the STA 1".

[0130] Since the TXOP of the AP 1 is shared with the STA 1, the STA 1 may send a frame to the AP 1 within SIFS or PIFS from the transmission time of the CTS frame. Within the shared TXOP, the STA 1 may be the TXOP holder or the TXOP owner. SIFS or PIFS may be a time shorter than the time Tw. The STA 1 may send a frame to the AP 1 and receive a response frame to the frame from the AP 1. In the present invention, the response frame may represent an ACK frame or a BA frame.

[0131] The shared TXOP can be terminated within the entire TXOP obtained by AP 1. When the shared TXOP is terminated by AP 1, STA 1 may not be able to send frames. Independent of the termination of the shared TXOP (e.g., TXOP sharing), STA 1 can wait for a time Tw starting from the time (e.g., the end time of reception) when a response frame (e.g., an ACK frame) is received to determine whether the conditions for transitioning from the normal transmit / receive state to the listening state are satisfied. When the shared TXOP is terminated, STA 1 can only check whether condition 1 is satisfied within the time Tw. After the shared TXOP is terminated, AP 1 can send frames to STA 1 within the remaining TXOPs of all TXOPs.

[0132] For example, AP 1 can send frames to STA 1 within a time Tw starting from the time (e.g., the reception time of the response frame + SIFS or PIFS) when a response frame (e.g., an ACK frame), which is the last frame received from STA 1, is received. STA 1 can receive frames from AP 1. Thus, the PHY-RXSTART.indication primitive can appear in the PHY layer of STA 1 within the time Tw. In this case, condition 1 can be satisfied, and STA 1 can receive frames from AP1 without transitioning to the listening state. In other words, if condition 1 is satisfied, STA 1 can maintain the normal receive / transmit state and perform communication with AP 1.

[0133] STA 1 can receive frames from AP 1, send a response frame (e.g., an ACK frame) for the frame to AP 1, and wait for a time Tw starting from the time when the response frame is received. In other words, STA 1 can determine whether the state retention condition is satisfied within the time Tw. There may be no frames (e.g., data) to be sent to AP 1 in STA 1. Therefore, the MAC layer of STA 1 may not pass the PHY-TXSTART.request primitive to the PHY layer of STA 1 within the time Tw. In this case, the PHY layer of STA 1 may not pass the PHY-TXSTART.confirm primitive, which is a response to the PHY-TXSTART.request primitive, to the MAC layer of STA 1.

[0134] Frames (e.g., data) to be sent to STA 1 may not exist in AP1. Thus, AP 1 may not send any frames to STA 1, and STA 1 may not receive any frames from AP 1. When no frames are received, the PHY layer of STA 1 may not generate a PHY-RXSTART.indication primitive. In other words, when no frames are received, the PHY-RXSTART.indication primitive may not appear in the PHY layer of STA 1 within time Tw. If neither condition 1 nor condition 2 is satisfied, STA 1 may operate in the listening state after time Tw. In other words, the operating state of STA 1 may change from the normal transmit / receive state to the listening state after time Tw.

[0135] As another approach, within the shared TXOP indicated by the MU-RTS frame of AP 1, STA 1 may not change its operating state from the normal transmit / receive state to the listening state. In other words, the operating state of STA 1 may remain in the normal transmit / receive state within the shared TXOP (e.g., within the time allocated by the MU-RTS TXS frame). After the end time of the shared TXOP, STA 1 may change its operating state from the normal transmit / receive state to the listening state. For example, when AP1 shares a TXOP with STA 1, STA 1 may operate as the TXOP owner within the shared TXOP. Alternatively, STA 1 may operate similar to the TXOP owner within the shared TXOP. In other words, just as STA 1 obtains a TXOP, STA 1 may operate in the EMLSR mode within the shared TXOP. "STA 1 operates in the EMLSR mode" may mean "STA 1 does not return to the listening state". In other words, "STA 1 operates in the EMLSR mode" may mean "STA 1 operates in a state where it can send and receive frames (i.e., the normal transmit / receive state)". When STA 1 connected to EMLSR STA MLD 1 obtains a TXOP, STA 1 may perform normal transmit / receive operations within the TXOP. In other words, STA 1 may send / receive frames within the TXOP.

[0136] For example, STA 1 can receive a MU-RTS TXS frame from AP 1 and send a CTS frame to AP 1 as a response to the MU-RTS TXS frame. In this case, the TXOP of AP 1 can be shared with STA 1. STA 1 can consider obtaining its TXOP within the shared TXOP (e.g., the time allocated by the MU-RTS TXS frame). STA 1 can operate as the TXOP owner within the shared TXOP. Alternatively, STA 1 can operate similarly to the TXOP owner within the shared TXOP. STA 1 can perform normal send / receive operations within the shared TXOP. STA 1 can send a frame to AP 1 within the shared TXOP. When the shared TXOP ends (e.g., expires, is interrupted), STA 1 can transition the operation state from the normal send / receive state to the listening state. The time required for STA 1 to transition the operation state from the normal send / receive state to the listening state can be time Tt (e.g., EMLSR transition delay time, EMLSR padding delay time). STA 1 can send a frame indicating an abrupt interruption of the shared TXOP to AP 1. In this frame, the RDG / More PPDU subfield of the Command and Status (CAS) field of the A control field included in the MAC header can be set to 0. The recipient of this frame can be AP 1. In other words, the shared TXOP can be terminated abruptly. STA 1 can transition the operation state to the listening state within time Tt after the time of receiving a frame (e.g., BA frame) as a response to the frame sent to AP 1. As another method, STA 1 may not have to receive a frame as a response to the frame sent to AP 1. In this case, STA 1 can transition the operation state from the normal send / receive state to the listening state after time Tt (EMLSR transition delay time, EMLSR padding delay time) from the frame's transmission time (e.g., transmission end time).

[0137] AP MLD 1 can send a TXS frame and / or an initial control frame (e.g., MU-RTS frame, MU-RTS trigger frame, MU-RTS TXS frame) to STA 1 of STA MLD 1. Then, AP MLD 1 can send an initial control frame to STA 2 of STA MLD 1 without using the EMLSR link (e.g., the second link) within the shared TXOP indicated by the MU-RTS frame.

[0138] Figure 6 is a timing diagram showing a fourth embodiment of the communication method of the EMLSR STA.

[0139] Reference Figure 6, a wireless local area network can support multi-link operation. AP MLD 1 and / or STA MLD 1 can operate on multiple links (e.g., the first link and the second link). The AP connected to AP MLD 1 operating on the first link can be referred to as AP 1. The AP connected to AP MLD 1 operating on the second link can be referred to as AP 2. The STA connected to STA MLD 1 operating on the first link can be referred to as STA 1. The STA connected to STA MLD 1 operating on the second link can be referred to as STA 2. STA MLD 1 can support EMLSR operation (e.g., MLSR operation). In other words, STA MLD 1 can be an EMLSR STA MLD (e.g., MLSR STA MLD). STA MLD 1 can perform EMLSR operations on multiple links (e.g., the first link and the second link). The STA connected to STA MLD 1 on each link can be referred to as an EMLSR STA. The STA 1 operating on the first link can be referred to as EMLSR STA 1, and the STA 2 operating on the second link can be referred to as EMLSR STA 2.

[0140] The EMLSR STA MLD can initiate or terminate EMLSR operation (or EMLSR mode) by exchanging Enhanced Multi-Link (EML) Operation Mode Notification (OMN) frames with the AP MLD. Before initiating or terminating the EMLSR mode, one of the STAs, STA 1 or STA 2, can perform normal transmit / receive operations and / or listening operations using a transceiver (e.g., a radio) at a preset time. STA 1 and STA 2 may not be able to perform normal transmit / receive operations simultaneously.

[0141] When the EMLSR STA MLD initiates the EMLSR mode by exchanging EML OMN frames, the EMLSR STA MLD can operate in the EMLSR mode on the EMLSR link negotiated between the EMLSR STA MLD and the AP MLD. In other words, the EMLSR STA MLD can perform EMLSR operations on the EMLSR link. In the EMLSR mode, the EMLSR STA MLD (e.g., EMLSR STA) can perform listening operations or normal transmit / receive operations. The EMLSR STA MLD can perform listening operations to receive frames with a predefined format (e.g., initial control frames) on the EMLSR link.

[0142] When receiving an initial control frame, the EMLSR STA MLD can transition all receive radios (e.g., all receive antennas) or all transmit / receive radios (e.g., all transmit / receive antennas) operating on links other than the link on which the initial control frame is received to the link on which the initial control frame is received, and perform normal transmit / receive operations on the link on which the initial control frame is received. In other words, the EMLSR STA MLD can transmit / receive frames with the AP MLD on the link on which the initial control frame is received. When the EMLSR STA MLD wishes to transmit a frame to the AP MLD, the EMLSR STA MLD can transition all radios to one of the EMLSR links and transmit the frame to the AP MLD by using the radios on one link (e.g., all radios).

[0143] STA 1 can perform normal transmit / receive operations and listening operations. The state of performing normal transmit / receive operations can be referred to as the normal transmit / receive state. The state of performing the listening operation can be referred to as the listening state. When performing normal transmit / receive operations, STA 1 can perform transmit / receive operations on all frames. In other words, STA 1 operating in the normal transmit / receive state can communicate on one link (e.g., the first link). When performing the listening operation, STA 1 can only receive frames with a predefined format. In other words, STA 1 operating in the listening state can perform a listening operation to receive frames on the EMLSR link. The frame with the predefined format can be an initial control frame. The initial control frame can be a MU-RTS frame or a BSRP trigger frame.

[0144] When the operating state of STA 1 is the listening state, STA 2 connected to the EMLSR STA MLD 1 can perform a listening operation. When the operating state of STA 1 is the normal transmit / receive state, the operating state of STA 2 connected to the EMLSR STA MLD 1 can be a state where it is unable to transmit / receive. In the state where it is unable to transmit / receive, STA 2 may not be able to transmit / receive frames. When STA 1 transitions from the listening state to the normal transmit / receive state, STA 2 can be in the state where it is unable to transmit / receive. During the time required to transition from the normal transmit / receive state to the listening state (e.g., the Tt time), STA 2 can be in the state where it is unable to transmit / receive. The change in the operating state can be similarly applied to STA 1 and STA 2 (e.g., STAs connected to the same EMLSR STA MLD). For example, if STA 2 is in the listening state, STA 1 can be in the listening state. If STA 2 is in the normal transmit / receive state, STA 1 can be in the state where it is unable to transmit / receive.

[0145] On the first link, AP 1 may configure (e.g., obtain, initiate) a TXOP before performing a transmit opportunity (TXOP) sharing operation. The TXOP may be configured (e.g., obtained, initiated) when "AP 1 performs the process of exchanging a request to send (RTS) frame and a clear to send (CTS) frame", "AP 1 sends a CTS-to-self frame", and / or "AP 1 sends a data frame". As another method, AP 1 may configure the TXOP by performing "the operation of sending a TXOP sharing (TXS) operation" and / or "the operation of sending an initial control frame (e.g., MU-RTS frame, MU-RTS trigger frame, MU-RTS TXS frame) and receiving a CTS frame".

[0146] Within the TXOP configured on the first link, AP 1 may send a MU-RTS frame to STA 1 (e.g., an EMLSR STA) without performing a channel contention process. The MU-RTS frame may be an initial control frame for EMLSR operation. The MU-RTS frame may be a frame indicating a TXOP sharing operation (e.g., a MU-RTS TXS frame). The difference between the MU-RTS TXS frame and the MU-RTS frame for an initial control frame (ICF) may be the value of a TXOP sharing mode subfield triggered included in a common information field. For example, the value of the TXOP sharing mode subfield triggered included in the MU-RTS TXS frame may be set to indicate TXOP sharing, and the value of the TXOP sharing mode subfield triggered included in the MU-RTS frame for the ICF may be set to a value not indicating TXOP sharing.

[0147] The recipient of the MU-RTS frame and the MU-RTS TXS frame for ICF can be a STA. Information about the STA as the recipient can be indicated by the user information field included in the MU-RTS frame and the MU-RTS TXS frame. The TXOP sharing operation can be a triggered TXOP sharing operation. For example, AP 1 can share a part or all of the TXOP with STA 1. The TXOP sharing mode can be set to 2. In this case, the recipients of the frames sent by STA 1 in the shared TXOP can be AP 1 and / or another STA. In other words, "when AP 1 shares the TXOP with STA 1 and the TXOP sharing mode is indicated as 2", STA 1 can send frames (e.g., data frames) to AP 1 and / or another STA sharing the TXOP and receive frames (e.g., data frames) from AP 1 and / or another STA sharing the TXOP within the shared TXOP. Therefore, the operation according to TXOP sharing mode 2 can be "the operation of STA 1 sending a data frame to AP 1 and / or another STA". STA 1 can perform an uplink transmission to the AP within the shared TXOP. Alternatively, STA 1 can perform communication with another STA (e.g., direct communication, peer to peer (P2P) communication) within the shared TXOP.

[0148] The EMLSR STA operating in the EMLSR mode can receive an initial control frame during the listening operation. In this case, in order to perform normal transmission / reception operations on the link where the initial control frame is received, the EMLSR STA can change the receiving radio from a link other than the link where the initial control frame is received to the link where the initial control frame is received. The time required to change the receiving radio can be time Tt. The time required to change from the normal transmission / reception state to the listening state can be time Tt. Time Tt can be the EMLSR transition delay or the EMLSR fill delay.

[0149] The MU-RTS frame as the initial control frame can indicate TXOP sharing. The length of the padding included in the MU-RTS frame should be longer than the length corresponding to time Tt, where time Tt is the time required for the operating state of the EMLSR STA to change from the listening state to the normal transmission / reception state. Therefore, in order to make the length of the padding included in the MU-RTS frame equal to or longer than the length corresponding to time Tt, the MU-RTS frame can include padding bits (e.g., padding bits). The padding bits can be bits used to increase the time length of the frame. STA 1 can receive the MU-RTS frame from AP 1. When receiving the MU-RTS frame of AP 1, STA1 can change the operating state from the listening state to the normal transmission / reception state.

[0150] STA 1 can decode the MU-RTS frame of AP 1 and confirm that AP 1 performs TXOP sharing based on the decoding result (e.g., information elements (e.g., fields) included in the MU-RTS frame). For example, STA 1 can identify the time indicated by the allocated duration subfield of the MU-RTS frame and identify the TXOP length shared by AP 1 based on the identified time. The shared TXOP length or / and the shared TXOP can be referred to as the time allocated by the MU-RTS TXS trigger frame. STA 1 can send a CTS frame to AP 1 after a short inter-frame space (SIFS) from the reception time (e.g., reception end time) of the MU-RTS frame of AP 1. STA 1 can confirm that a media access control (MAC) primitive and / or a PHY primitive occurs during a time Tw from the transmission time (e.g., transmission end time) of the CTS frame. The operation of STA 1 based on the primitive (e.g., MAC primitive and / or PHY primitive) that occurs during the time Tw can be performed based on the following conditions. The time Tw can be aSIFSTime + aSlotTime + aRxPHYStartDelay.

[0151] If one or more of the following conditions are satisfied during the time Tw, STA 1 may not change the operation state from the normal transmission / reception state to the listening state.

[0152] - Condition 1: The PHY-RXSTART.indication primitive appears in the PHY layer of STA 1.

[0153] - Condition 2: The MAC layer of STA 1 passes the PHY-RXSTART.indication primitive to the PHY layer of STA 1, and the PHY layer passes the PHY-TXSTART.confirm primitive to the MAC layer as a response to a request (e.g., the PHY-TXSTART.request primitive).

[0154] If neither condition 1 nor condition 2 is satisfied, STA 1 can change its operation state from the normal transmission / reception state to the listening state. Each of condition 1 and condition 2 can be a state maintenance condition (or a state transition condition). If the state maintenance condition (e.g., at least one state maintenance condition) is satisfied within a preset time (e.g., time Tw), STA 1 can maintain its current operation state (e.g., the normal transmission / reception state). If the state maintenance condition (e.g., all state maintenance conditions) is not satisfied within the preset time (e.g., time Tw), STA 1 can change its current operation state. In this document, STA 1 can change its operation state from the normal transmission / reception state to the listening state. Condition 1 can represent "the condition for STA 1 to receive a frame from another communication node (e.g., AP 1 or another STA)". Condition 2 can represent "the condition for a frame to be sent to another communication node (e.g., AP 1 or another STA) to appear in STA 1".

[0155] Since the TXOP of AP 1 is shared with STA 1, STA 1 can send a frame to AP 1 and / or another STA (e.g., STA X) within SIFS or PIFS from the transmission time of the CTS frame. Within the shared TXOP, STA 1 can be the TXOP holder or the TXOP owner. SIFS or PIFS can be a time shorter than time Tw. STA 1 can send a frame to AP 1 and receive a response frame to the frame from AP 1. Alternatively, STA 1 can send a frame to another STA and receive a response frame to the frame from another STA. In the present invention, the response frame can represent an ACK frame or a BA frame.

[0156] STA 1 can wait for time Tw starting from the time when it receives a response frame from AP 1 or another STA. In other words, STA 1 can determine whether the state maintenance condition is satisfied within time Tw. A frame (e.g., data) to be sent to AP 1 or another STA may not exist in STA 1. Therefore, the MAC layer of STA 1 may not pass the PHY-TXSTART.request primitive to the PHY layer of STA 1 within time Tw. In this case, the PHY layer of STA 1 may not pass the PHY-TXSTART.confirm primitive, which is a response to the PHY-TXSTART.request primitive, to the MAC layer of STA 1.

[0157] Frames (e.g., data) to be sent to STA 1 may not exist in AP 1 or another STA. Thus, AP 1 or another STA may not send any frames to STA 1, and STA 1 may not receive any frames from AP 1 or another STA. When no frames are received, the PHY layer of STA 1 may not generate a PHY-RXSTART.indication primitive. In other words, when no frames are received, the PHY-RXSTART.indication primitive may not appear in the PHY layer of STA 1 within time Tw. If neither condition 1 nor condition 2 is satisfied, STA 1 may operate in a listening state after time Tw. In other words, the operating state of STA 1 may change from the normal transmit / receive state to the listening state after time Tw.

[0158] As another approach, within the shared TXOP indicated by the MU-RTS frame of AP 1, STA 1 may not change its operating state from the normal transmit / receive state to the listening state. In other words, the operating state of STA 1 may remain in the normal transmit / receive state within the shared TXOP (e.g., within the time allocated by the MU-RTS TXS frame). After the end time of the shared TXOP, STA 1 may change its operating state from the normal transmit / receive state to the listening state. For example, when AP1 shares a TXOP with STA 1, STA 1 may operate as the TXOP owner within the shared TXOP. Alternatively, STA 1 may operate similarly to the TXOP owner within the shared TXOP. In other words, just as STA 1 obtains a TXOP, STA 1 may operate in the EMLSR mode within the shared TXOP. "STA 1 operates in the EMLSR mode" may mean "STA 1 does not return to the listening state". "STA 1 operates in the EMLSR mode" may mean "STA 1 operates in a state where it can send and receive frames (i.e., the normal transmit / receive state)". When STA 1, which is connected to the EMLSR STA MLD 1, obtains a TXOP, STA 1 may perform normal transmit / receive operations within the TXOP. In other words, STA 1 may send / receive frames within the TXOP.

[0159] For example, STA 1 can receive a MU-RTS TXS frame from AP 1 and send a CTS frame to AP 1 as a response to the MU-RTS TXS frame. In this case, the TXOP of AP 1 can be shared with STA 1. STA 1 can consider obtaining its own TXOP within the shared TXOP (e.g., the time allocated by the MU-RTS TXS frame). STA 1 can operate as the TXOP owner within the shared TXOP. Alternatively, STA 1 can operate similarly to the TXOP owner within the shared TXOP. STA 1 can perform normal send / receive operations within the shared TXOP. STA 1 can send frames to AP 1 and / or another STA within the shared TXOP. When the shared TXOP ends (e.g., expires, is interrupted), STA 1 can transition the operation state from the normal send / receive state to the listening state. The time required for STA 1 to transition the operation state from the normal send / receive state to the listening state can be time Tt (e.g., EMLSR transition delay time, EMLSR padding delay time). STA 1 can send a frame indicating an abrupt interruption of the shared TXOP to AP 1. In this frame, the RDG / More PPDU subfield of the Command and Status (CAS) field of the A control field included in the MAC header can be set to 0. The recipient of this frame can be AP 1. In other words, the shared TXOP can be terminated abruptly. STA 1 can transition the operation state to the listening state within time Tt after the time of receiving a frame (e.g., a block ACK frame) as a response to the frame sent to AP 1. As another method, STA 1 may not have to receive a frame as a response to the frame sent to AP 1. In this case, STA 1 can transition the operation state from the normal send / receive state to the listening state after time Tt (EMLSR transition delay time, EMLSR padding delay time) from the frame's transmission time (e.g., the end of transmission).

[0160] AP MLD 1 can send a TXS frame and / or an initial control frame (e.g., a MU-RTS frame, a MU-RTS trigger frame, a MU-RTS TXS frame) to STA 1 of STA MLD 1. Then, AP MLD 1 can send an initial control frame to STA 2 of STA MLD 1 without using the EMLSR link (e.g., the second link) within the shared TXOP indicated by the MU-RTS frame.

[0161] Figure 7 is a timing diagram showing a fifth embodiment of the communication method of the EMLSR STA.

[0162] Reference Figure 7, a wireless local area network can support multi-link operation. AP MLD 1 and / or STA MLD 1 can operate on multiple links (e.g., the first link and the second link). The AP connected to AP MLD 1 operating on the first link can be referred to as AP 1. The AP connected to AP MLD 1 operating on the second link can be referred to as AP 2. The STA connected to STA MLD 1 operating on the first link can be referred to as STA 1. The STA connected to STA MLD 1 operating on the second link can be referred to as STA 2. STA MLD 1 can support EMLSR operation (e.g., MLSR operation). In other words, STA MLD 1 can be an EMLSR STA MLD (e.g., MLSR STA MLD). STA MLD 1 can perform EMLSR operations on multiple links (e.g., the first link and the second link). The STA connected to STA MLD 1 on each link can be referred to as an EMLSR STA. The STA 1 operating on the first link can be referred to as EMLSR STA 1, and the STA 2 operating on the second link can be referred to as EMLSR STA 2.

[0163] The EMLSR STA MLD can initiate or terminate the EMLSR operation (or EMLSR mode) by exchanging enhanced multi-link (EML) operation mode notification (OMN) frames with the AP MLD. Before initiating or terminating the EMLSR mode, one of the STAs, STA 1 or STA 2, can perform normal transmit / receive operations and / or listening operations using a transceiver (e.g., a radio) at a preset time. STA 1 and STA 2 may not be able to perform normal transmit / receive operations simultaneously.

[0164] When the EMLSR STA MLD initiates the EMLSR mode by exchanging EML OMN frames, the EMLSR STA MLD can operate in the EMLSR mode on the EMLSR link negotiated between the EMLSR STA MLD and the AP MLD. In other words, the EMLSR STA MLD can perform EMLSR operations on the EMLSR link. In the EMLSR mode, the EMLSR STA MLD (e.g., EMLSR STA) can perform listening operations or normal transmit / receive operations. The EMLSR STA MLD can perform listening operations to receive frames with a predefined format (e.g., initial control frames) on the EMLSR link.

[0165] When receiving an initial control frame, the EMLSR STA MLD can transition all receive radios (e.g., all receive antennas) or all transmit / receive radios (e.g., all transmit / receive antennas) operating on links other than the link on which the initial control frame is received to the link on which the initial control frame is received, and perform normal transmit / receive operations on the link on which the initial control frame is received. In other words, the EMLSR STA MLD can transmit / receive frames with the AP MLD on the link on which the initial control frame is received. When the EMLSR STA MLD wishes to transmit a frame to the AP MLD, the EMLSR STA MLD can transition all radios to one of the EMLSR links and transmit the frame to the AP MLD by using the radios on one link (e.g., all radios).

[0166] STA 1 can perform normal transmit / receive operations and listening operations. The state of performing normal transmit / receive operations can be referred to as the normal transmit / receive state. The state of performing listening operations can be referred to as the listening state. When performing normal transmit / receive operations, STA 1 can perform transmit / receive operations on all frames. In other words, STA 1 operating in the normal transmit / receive state can perform communication on one link (e.g., the first link). When performing listening operations, STA 1 can only receive frames with a predefined format. In other words, STA 1 operating in the listening state can perform a listening operation to receive frames on the EMLSR link. The frame with a predefined format can be an initial control frame. The initial control frame can be a MU-RTS frame or a BSRP trigger frame.

[0167] When the operating state of STA 1 is the listening state, STA 2 connected to the EMLSR STA MLD 1 can perform a listening operation. When the operating state of STA 1 is the normal transmit / receive state, the operating state of STA 2 connected to the EMLSR STA MLD 1 can be a state where it cannot transmit / receive. In the state where it cannot transmit / receive, STA 2 may not be able to transmit / receive frames. When STA 1 transitions from the listening state to the normal transmit / receive state, STA 2 can be in the state where it cannot transmit / receive. During the time required to transition from the normal transmit / receive state to the listening state (e.g., Tt time), STA 2 can be in the state where it cannot transmit / receive. The change in the operating state can be similarly applied to STA 1 and STA 2 (e.g., STAs connected to the same EMLSR STA MLD). For example, if STA 2 is in the listening state, STA 1 can be in the listening state. If STA 2 is in the normal transmit / receive state, STA 1 can be in the state where it cannot transmit / receive.

[0168] On the first link, AP 1 may configure (e.g., obtain, initiate) a TXOP before performing a transmit opportunity (TXOP) sharing operation. The TXOP may be configured (e.g., obtained, initiated) when "AP 1 performs the process of exchanging a request to send (RTS) frame and a clear to send (CTS) frame", "AP 1 sends a CTS-to-self frame", and / or "AP 1 sends a data frame". As another approach, AP 1 may configure the TXOP by performing "the operation of sending a TXOP sharing (TXS) operation" and / or "the operation of sending an initial control frame (e.g., MU-RTS frame, MU-RTS trigger frame, MU-RTS TXS frame) and receiving a CTS frame".

[0169] Within the TXOP configured on the first link, AP 1 may send a MU-RTS frame to STA 1 (e.g., an EMLSR STA) without performing a channel contention process. The MU-RTS frame may be an initial control frame for EMLSR operation. The MU-RTS frame may be a frame indicating a TXOP sharing operation (e.g., a MU-RTS TXS frame). The difference between the MU-RTS TXS frame and the MU-RTS frame for an initial control frame (ICF) may be the value of the TXOP sharing mode subfield triggered included in the common information field. For example, the value of the TXOP sharing mode subfield triggered included in the MU-RTS TXS frame may be set to a value indicating TXOP sharing, and the value of the TXOP sharing mode subfield triggered included in the MU-RTS frame for the ICF may be set to a value not indicating TXOP sharing.

[0170] The receiver of the MU-RTS frame and the MU-RTS TXS frame for ICF can be a STA. Information about the STA as the receiver can be indicated by the user information field included in the MU-RTS frame and the MU-RTS TXS frame. The TXOP sharing operation can be a triggered TXOP sharing operation. For example, AP 1 can share a part or all of the TXOP with STA 1. The TXOP sharing mode can be set to 2. In this case, the receivers of the frames sent by STA 1 in the shared TXOP can be AP 1 and / or another STA. In other words, "when AP 1 shares the TXOP with STA 1 and the TXOP sharing mode is indicated as 2", STA 1 can send frames (e.g., data frames) to AP 1 and / or another STA sharing the TXOP and receive frames (e.g., data frames) from AP 1 and / or another STA sharing the TXOP within the shared TXOP. Therefore, the operation according to TXOP sharing mode 2 can be "the operation of STA 1 sending a data frame to AP 1 and / or another STA". STA 1 can perform an uplink transmission to the AP within the shared TXOP. Alternatively, STA 1 can perform communication with another STA (e.g., direct communication, P2P communication) within the shared TXOP.

[0171] The EMLSR STA operating in the EMLSR mode can receive an initial control frame during the listening operation. In this case, in order to perform normal send / receive operations on the link where the initial control frame is received, the EMLSR STA can change the receiving radio from a link other than the link where the initial control frame is received to the link where the initial control frame is received. The time required to change the receiving radio can be time Tt. The time required to change from the normal send / receive state to the listening state can be time Tt. Time Tt can be the EMLSR transition delay or the EMLSR fill delay.

[0172] The MU-RTS frame as the initial control frame can indicate TXOP sharing. The length of the padding included in the MU-RTS frame should be longer than the length corresponding to time Tt, where time Tt is the time required for the operating state of the EMLSR STA to change from the listening state to the normal send / receive state. Therefore, in order to make the length of the padding included in the MU-RTS frame equal to or longer than the length corresponding to time Tt, the MU-RTS frame can include padding bits (e.g., padding bits). The padding bits can be bits used to increase the time length of the frame. STA 1 can receive the MU-RTS frame from AP 1. When receiving the MU-RTS frame from AP 1, STA1 can change the operating state from the listening state to the normal send / receive state.

[0173] STA 1 can decode the MU-RTS frame of AP 1 and confirm that AP 1 performs TXOP sharing based on the decoding result (e.g., the information element (e.g., field) included in the MU-RTS frame). For example, STA 1 can identify the time indicated by the allocation duration subfield of the MU-RTS frame and identify the TXOP length shared by AP 1 based on the identified time. The shared TXOP length or / and the shared TXOP can be referred to as the time allocated by the MU-RTS TXS trigger frame. STA 1 can send a CTS frame to AP 1 after a short inter-frame space (SIFS) from the reception time (e.g., the reception end time) of the MU-RTS frame of AP 1. STA 1 can confirm that a media access control (MAC) primitive and / or a PHY primitive occurs during a time Tw from the transmission time (e.g., the transmission end time) of the CTS frame. The operation of STA 1 based on the primitive (e.g., MAC primitive and / or PHY primitive) occurring during the time Tw can be performed based on the following conditions. The time Tw can be aSIFSTime + aSlotTime + aRxPHYStartDelay.

[0174] If one or more of the following conditions are satisfied during the time Tw, STA 1 may not change the operation state from the normal transmission / reception state to the listening state.

[0175] - Condition 1: The PHY-RXSTART.indication primitive appears in the PHY layer of STA 1.

[0176] - Condition 2: The MAC layer of STA 1 passes the PHY-RXSTART.indication primitive to the PHY layer of STA 1, and the PHY layer passes the PHY-TXSTART.confirm primitive to the MAC layer as a response to a request (e.g., the PHY-TXSTART.request primitive).

[0177] If neither Condition 1 nor Condition 2 is satisfied, STA 1 may change its operation state from the normal transmission / reception state to the listening state. Each of Condition 1 and Condition 2 may be a state maintenance condition (or a state transition condition). If the state maintenance condition (e.g., at least one state maintenance condition) is satisfied within a preset time (e.g., time Tw), STA 1 may maintain its current operation state (e.g., the normal transmission / reception state). If the state maintenance condition (e.g., all state maintenance conditions) is not satisfied within the preset time (e.g., time Tw), STA 1 may change its current operation state. In this document, STA 1 may change its operation state from the normal transmission / reception state to the listening state. Condition 1 may represent "the condition for STA 1 to receive a frame from another communication node (e.g., AP 1 or another STA)". Condition 2 may represent "the condition for a frame to be sent to another communication node (e.g., AP 1 or another STA) to appear in STA 1".

[0178] Since the TXOP of AP 1 is shared with STA 1, STA 1 may send a frame to AP 1 and / or another STA (e.g., STA X) within SIFS or PIFS from the transmission time of the CTS frame. Within the shared TXOP, STA 1 may be the TXOP holder or the TXOP owner. SIFS or PIFS may be a time shorter than time Tw. STA 1 may send a frame to AP 1 and receive a response frame to the frame from AP 1. Alternatively, STA 1 may send a frame to another STA and receive a response frame to the frame from another STA. In the present invention, the response frame may represent an ACK frame or a BA frame.

[0179] STA 1 may wait for time Tw starting from the time when it receives a response frame from AP 1 or another STA. In other words, STA 1 may determine whether the state maintenance condition is satisfied within time Tw. A frame (e.g., data) to be sent to AP 1 and / or another STA may exist in STA 1. Therefore, the MAC layer of STA 1 may pass a PHY-TXSTART.request primitive to the PHY layer of STA 1 within time Tw. In this case, the PHY layer of STA 1 may receive the PHY-TXSTART.request primitive from the MAC layer of STA 1 and pass a PHY-TXSTART.confirm primitive to the MAC layer of STA 1 as a response to the PHY-TXSTART.request primitive. In this case, Condition 2 may be satisfied, and STA 1 may not change its operation state from the normal transmission / reception state to the listening state after time Tw.

[0180] STA 1 can send a frame to AP 1 or another STA after SIFS from the reception time (e.g., the end of reception time) of an ACK frame of AP 1 or another STA. STA 1 can receive a response frame (e.g., ACK frame, BA frame) for the frame from AP 1 or another STA. STA 1 can wait for a time Tw starting from the time when it receives the response frame from AP 1 or another STA. The frame (e.g., data) to be sent to AP 1 and / or another STA may not exist in STA 1. Therefore, the MAC layer of STA 1 may not pass the PHY-TXSTART.request primitive to the PHY layer of STA 1 within the time Tw. In this case, the PHY layer of STA 1 may not pass the PHY-TXSTART.confirm primitive as a response to the PHY-TXSTART.request primitive to the MAC layer of STA 1.

[0181] The frame (e.g., data) to be sent to STA 1 may not exist in AP 1 and / or another STA. Therefore, AP 1 and / or another STA may not send any frame to STA 1, and STA 1 may not receive any frame from AP 1 and / or another STA. When no frame is received, the PHY layer of STA 1 may not generate a PHY-RXSTART.indication primitive. In other words, when no frame is received, the PHY-RXSTART.indication primitive may not appear in the PHY layer of STA 1 within the time Tw. If neither condition 1 nor condition 2 is satisfied, STA 1 can operate in a listening state after the time Tw. In other words, the operating state of STA 1 can change from the normal transmission / reception state to the listening state after the time Tw.

[0182] As another approach, in the shared TXOP indicated by the MU-RTS frame of AP 1, STA 1 may not transition its operation state from the normal transmit / receive state to the listening state. In other words, the operation state of STA 1 may remain in the normal transmit / receive state within the shared TXOP (e.g., within the time allocated by the MU-RTS TXS frame). After the end time of the shared TXOP, STA 1 may transition its operation state from the normal transmit / receive state to the listening state. For example, when AP1 shares a TXOP with STA 1, STA 1 may operate as the TXOP owner within the shared TXOP. Alternatively, STA 1 may operate similarly to the TXOP owner within the shared TXOP. In other words, just as STA 1 obtains a TXOP, STA 1 may operate in the EMLSR mode within the shared TXOP. "STA 1 operates in the EMLSR mode" may mean "STA 1 does not return to the listening state". "STA 1 operates in the EMLSR mode" may mean "STA 1 operates in a state where it can transmit and receive frames (e.g., the normal transmit / receive state)". When STA 1, which is connected to the EMLSR STA MLD 1, obtains a TXOP, STA1 may perform normal transmit / receive operations within the TXOP. In other words, STA 1 may transmit / receive frames within the TXOP.

[0183] For example, STA 1 can receive a MU-RTS TXS frame from AP 1 and send a CTS frame to AP 1 as a response to the MU-RTS TXS frame. In this case, the TXOP of AP 1 can be shared with STA 1. STA 1 can consider obtaining its TXOP within the shared TXOP (e.g., the time allocated by the MU-RTS TXS frame). STA 1 can operate as a TXOP owner within the shared TXOP. Alternatively, STA 1 can operate within the shared TXOP similar to a TXOP owner. STA 1 can perform normal send / receive operations within the shared TXOP. STA 1 can send frames to AP 1 and / or another STA within the shared TXOP. When the shared TXOP ends (e.g., expires, is interrupted), STA 1 can transition its operation state from the normal send / receive state to the listening state. The time required for STA 1 to transition its operation state from the normal send / receive state to the listening state can be time Tt (e.g., EMLSR transition delay time, EMLSR padding delay time). STA 1 can send a frame indicating an intermediate interruption of the shared TXOP to AP 1. In this frame, the RDG / More PPDU subfield of the Command and Status (CAS) field of the A control field included in the MAC header can be set to 0. The recipient of this frame can be AP 1. In other words, the shared TXOP can be terminated midway. STA 1 can transition its operation state to the listening state within time Tt after the time of receiving a frame (e.g., BA frame) as a response to the frame sent to AP 1. As another method, STA 1 may not have to receive a frame as a response to the frame sent to AP 1. In this case, STA 1 can transition its operation state from the normal send / receive state to the listening state after time Tt (EMLSR transition delay time, EMLSR padding delay time) from the frame's transmission time (e.g., transmission end time).

[0184] AP MLD 1 can send a TXS frame and / or an initial control frame (e.g., MU-RTS frame, MU-RTS trigger frame, MU-RTS TXS frame) to STA 1 of STA MLD 1. Then, AP MLD 1 can send an initial control frame to STA 2 of STA MLD 1 without using the EMLSR link (e.g., the second link) within the shared TXOP indicated by the MU-RTS frame.

[0185] Figure 8 is a timing diagram showing a sixth embodiment of the communication method of the EMLSR STA.

[0186] Reference Figure 8, a wireless local area network can support multi-link operation. AP MLD 1 and / or STA MLD 1 can operate on multiple links (e.g., the first link and the second link). An AP connected to AP MLD 1 operating on the first link can be referred to as AP 1. An AP connected to AP MLD 1 operating on the second link can be referred to as AP 2. A STA connected to STA MLD 1 operating on the first link can be referred to as STA 1. A STA connected to STA MLD 1 operating on the second link can be referred to as STA 2. STA MLD 1 can support EMLSR operation (e.g., MLSR operation). In other words, STA MLD 1 can be an EMLSR STA MLD (e.g., MLSR STA MLD). STA MLD 1 can perform EMLSR operation on multiple links (e.g., the first link and the second link). A STA connected to STA MLD 1 on each link can be referred to as an EMLSR STA. The STA 1 operating on the first link can be referred to as EMLSR STA 1, and the STA 2 operating on the second link can be referred to as EMLSR STA 2.

[0187] The EMLSR STA MLD can initiate or terminate the EMLSR operation (or EMLSR mode) by exchanging Enhanced Multi-Link (EML) Operation Mode Notification (OMN) frames with the AP MLD. Before initiating or terminating the EMLSR mode, one of the STAs, STA 1 or STA 2, can perform normal transmission / reception operations and / or listening operations using a transceiver (e.g., a radio) at a preset time. STA 1 and STA 2 may not be able to perform normal transmission / reception operations simultaneously.

[0188] When the EMLSR STA MLD initiates the EMLSR mode by exchanging EML OMN frames, the EMLSR STA MLD can operate in the EMLSR mode on the EMLSR link negotiated between the EMLSR STA MLD and the AP MLD. In other words, the EMLSR STA MLD can perform EMLSR operation on the EMLSR link. In the EMLSR mode, the EMLSR STA MLD (e.g., EMLSR STA) can perform listening operations or normal transmission / reception operations. The EMLSR STA MLD can perform listening operations to receive frames with a predefined format (e.g., initial control frames) on the EMLSR link.

[0189] When receiving an initial control frame, the EMLSR STA MLD may transition all receive radios (e.g., all receive antennas) or all transmit / receive radios (e.g., all transmit / receive antennas) operating on links other than the link on which the initial control frame is received to the link on which the initial control frame is received, and perform normal transmit / receive operations on the link on which the initial control frame is received. In other words, the EMLSR STA MLD may transmit / receive frames with the AP MLD on the link on which the initial control frame is received. When the EMLSR STA MLD wishes to transmit a frame to the AP MLD, the EMLSR STA MLD may transition all radios to one of the EMLSR links and transmit the frame to the AP MLD by using the radios on one link (e.g., all radios).

[0190] STA 1 may perform normal transmit / receive operations and listening operations. The state of performing normal transmit / receive operations may be referred to as the normal transmit / receive state. The state of performing listening operations may be referred to as the listening state. When performing normal transmit / receive operations, STA 1 may perform transmit / receive operations on all frames. In other words, STA 1 operating in the normal transmit / receive state may communicate on one link (e.g., the first link). When performing listening operations, STA 1 may only receive frames with a predefined format. In other words, STA 1 operating in the listening state may perform listening operations to receive frames on the EMLSR link. The frame with a predefined format may be an initial control frame. The initial control frame may be a MU-RTS frame or a BSRP trigger frame.

[0191] When the operating state of STA 1 is the listening state, STA 2 connected to the EMLSR STA MLD 1 may perform listening operations. When the operating state of STA 1 is the normal transmit / receive state, the operating state of STA 2 connected to the EMLSR STA MLD 1 may be a state where it cannot transmit / receive. In the state where it cannot transmit / receive, STA 2 may not be able to transmit / receive frames. When STA 1 transitions from the listening state to the normal transmit / receive state, STA 2 may be in the state where it cannot transmit / receive. During the time required to transition from the normal transmit / receive state to the listening state (e.g., the Tt time), STA 2 may be in the state where it cannot transmit / receive. The change in the operating state may be similarly applied to STA 1 and STA 2 (e.g., STAs connected to the same EMLSR STA MLD). For example, if STA 2 is in the listening state, STA 1 may be in the listening state. If STA 2 is in the normal transmit / receive state, STA 1 may be in the state where it cannot transmit / receive.

[0192] On the first link, AP 1 may configure (e.g., obtain, initiate) a TXOP before performing a transmit opportunity (TXOP) sharing operation. The TXOP may be configured (e.g., obtained, initiated) when "AP 1 performs the process of exchanging a request to send (RTS) frame and a clear to send (CTS) frame", "AP 1 sends a CTS-to-self frame", and / or "AP 1 sends a data frame". As another approach, AP 1 may configure the TXOP by performing "the operation of sending a TXOP sharing (TXS) operation" and / or "the operation of sending an initial control frame (e.g., MU-RTS frame, MU-RTS trigger frame, MU-RTS TXS frame) and receiving a CTS frame".

[0193] Within the TXOP configured on the first link, AP 1 may send a MU-RTS frame to STA 1 (e.g., an EMLSR STA) without performing a channel contention process. The MU-RTS frame may be an initial control frame for EMLSR operation. The MU-RTS frame may be a frame indicating a TXOP sharing operation (e.g., a MU-RTS TXS frame). The difference between the MU-RTS TXS frame and the MU-RTS frame for an initial control frame (ICF) may be the value of a TXOP sharing mode subfield triggered included in a common information field. For example, the value of the TXOP sharing mode subfield triggered included in the MU-RTS TXS frame may be set to a value indicating TXOP sharing, and the value of the TXOP sharing mode subfield triggered included in the MU-RTS frame for the ICF may be set to a value not indicating TXOP sharing.

[0194] The receiver of the MU-RTS frame and the MU-RTS TXS frame for ICF can be a STA. Information about the STA as the receiver can be indicated by the user information field included in the MU-RTS frame and the MU-RTS TXS frame. The TXOP sharing operation can be a triggered TXOP sharing operation. For example, AP 1 can share a part or all of the TXOP with STA 1. The TXOP sharing mode can be set to 2. In this case, the receivers of the frames sent by STA 1 in the shared TXOP can be AP 1 and / or another STA. In other words, "when AP 1 shares the TXOP with STA 1 and the TXOP sharing mode is indicated as 2", STA 1 can send frames (e.g., data frames) to AP 1 and / or another STA sharing the TXOP and receive frames (e.g., data frames) from AP 1 and / or another STA sharing the TXOP within the shared TXOP. Therefore, the operation according to TXOP sharing mode 2 can be "the operation of STA 1 sending a data frame to AP 1 and / or another STA". STA 1 can perform an uplink transmission to the AP within the shared TXOP. Alternatively, STA 1 can perform communication with another STA (e.g., direct communication, P2P communication) within the shared TXOP.

[0195] The EMLSR STA operating in the EMLSR mode can receive an initial control frame during the listening operation. In this case, in order to perform normal send / receive operations on the link where the initial control frame is received, the EMLSR STA can change the receive radio from a link other than the link where the initial control frame is received to the link where the initial control frame is received. The time required to change the receive radio can be time Tt. The time required to change from the normal send / receive state to the listening state can be time Tt. Time Tt can be the EMLSR transition delay or the EMLSR fill delay.

[0196] The MU-RTS frame as the initial control frame can indicate TXOP sharing. The length of the padding included in the MU-RTS frame should be longer than the length corresponding to time Tt, where time Tt is the time required for the operating state of the EMLSR STA to change from the listening state to the normal send / receive state. Therefore, in order to make the length of the padding included in the MU-RTS frame equal to or longer than the length corresponding to time Tt, the MU-RTS frame can include padding bits (e.g., padding bits). The padding bits can be bits used to increase the time length of the frame. STA 1 can receive the MU-RTS frame from AP 1. When receiving the MU-RTS frame of AP 1, STA1 can change the operating state from the listening state to the normal send / receive state.

[0197] STA 1 can decode the MU-RTS frame of AP 1 and confirm that AP 1 performs TXOP sharing based on the decoding result (e.g., information elements (e.g., fields) included in the MU-RTS frame). For example, STA 1 can identify the time indicated by the allocation duration subfield of the MU-RTS frame and identify the TXOP length shared by AP 1 based on the identified time. The shared TXOP length or / and the shared TXOP can be referred to as the time allocated by the MU-RTS TXS trigger frame. STA 1 can send a CTS frame to AP 1 after a short inter-frame space (SIFS) from the reception time (e.g., reception end time) of the MU-RTS frame of AP 1. STA 1 can confirm that a media access control (MAC) primitive and / or a PHY primitive occurs during a time Tw from the transmission time (e.g., transmission end time) of the CTS frame. The operation of STA 1 based on the primitive (e.g., MAC primitive and / or PHY primitive) that occurs during the time Tw can be performed based on the following conditions. The time Tw can be aSIFSTime + aSlotTime + aRxPHYStartDelay.

[0198] If one or more of the following conditions are satisfied during the time Tw, STA 1 may not change the operation state from the normal transmit / receive state to the listening state.

[0199] - Condition 1: The PHY-RXSTART.indication primitive appears in the PHY layer of STA 1.

[0200] - Condition 2: The MAC layer of STA 1 passes the PHY-RXSTART.indication primitive to the PHY layer of STA 1, and the PHY layer passes the PHY-TXSTART.confirm primitive to the MAC layer as a response to a request (e.g., the PHY-TXSTART.request primitive).

[0201] If neither Condition 1 nor Condition 2 is satisfied, STA 1 can change its operation state from the normal transmission / reception state to the listening state. Each of Condition 1 and Condition 2 can be a state maintenance condition (or a state transition condition). If the state maintenance condition (e.g., at least one state maintenance condition) is satisfied within a preset time (e.g., time Tw), STA 1 can maintain its current operation state (e.g., the normal transmission / reception state). If the state maintenance condition (e.g., all state maintenance conditions) is not satisfied within the preset time (e.g., time Tw), STA 1 can change its current operation state. In this document, STA 1 can change its operation state from the normal transmission / reception state to the listening state. Condition 1 can represent "the condition for STA 1 to receive a frame from another communication node (e.g., AP 1 or another STA)". Condition 2 can represent "the condition that a frame to be transmitted to another communication node (e.g., AP 1 or another STA) appears at STA 1".

[0202] Since the TXOP of AP 1 is shared with STA 1, STA 1 can send a frame to AP 1 and / or another STA (e.g., STA X) within SIFS or PIFS from the transmission time of the CTS frame. Within the shared TXOP, STA 1 can be the TXOP holder or the TXOP owner. SIFS or PIFS can be a time shorter than time Tw. STA 1 can send a frame to AP 1 and receive a response frame for the frame from AP 1. Alternatively, STA 1 can send a frame to another STA and receive a response frame for the frame from another STA. In the present invention, the response frame can represent an ACK frame or a BA frame.

[0203] The shared TXOP can be terminated within the entire TXOP obtained by AP 1. When the shared TXOP is terminated by AP 1, STA 1 may not be able to send a frame. Independent of the termination of the shared TXOP (e.g., TXOP sharing), STA 1 can wait for time Tw starting from the time (e.g., the reception end time) when it receives a response frame (e.g., an ACK frame) to determine whether the condition for changing from the normal transmission / reception state to the listening state is satisfied. When the shared TXOP is terminated, STA 1 can only check whether Condition 1 is satisfied within time Tw. After the shared TXOP is terminated, AP 1 can send a frame to STA 1 within the remaining TXOP of all TXOPs.

[0204] For example, AP 1 can send a frame to STA 1 at time Tw starting from the time when it receives a response frame (e.g., ACK frame), which is the last frame received from STA 1 (e.g., the reception time of the response frame + SIFS or PIFS). Therefore, the PHY-RXSTART.indication primitive can appear in the PHY layer of STA 1 within time Tw. In this case, condition 1 can be satisfied, and STA 1 can receive a frame from AP 1 without transitioning to the listening state. In other words, if condition 1 is satisfied, then STA 1 can maintain the normal receive / transmit state and receive a frame from AP 1.

[0205] STA 1 can receive a frame from AP 1, send a response frame (e.g., ACK frame) for the frame to AP 1, and wait for time Tw starting from the time when it receives the response frame. In other words, STA 1 can determine whether the state holding condition is satisfied within time Tw. There may be no frame (e.g., data) to be sent to AP 1 in STA 1. Therefore, the MAC layer of STA 1 may not pass the PHY-TXSTART.request primitive to the PHY layer of STA 1 within time Tw. In this case, the PHY layer of STA 1 may not pass the PHY-TXSTART.confirm primitive, which is a response to the PHY-TXSTART.request primitive, to the MAC layer of STA 1.

[0206] There may be no frame (e.g., data) to be sent to STA 1 in AP 1 and / or another STA. Therefore, AP 1 and / or another STA may not send any frame to STA 1, and STA 1 may not receive any frame from AP 1 and / or another STA. When no frame is received, the PHY layer of STA 1 may not generate the PHY-RXSTART.indication primitive. In other words, when no frame is received, the PHY-RXSTART.indication primitive may not appear in the PHY layer of STA 1 within time Tw. If neither condition 1 nor condition 2 is satisfied, then STA 1 can operate in the listening state after time Tw. In other words, the operating state of STA 1 can transition from the normal transmit / receive state to the listening state after time Tw.

[0207] As another approach, in the shared TXOP indicated by the MU-RTS frame of AP 1, STA 1 may not transition its operation state from the normal transmit / receive state to the listening state. In other words, the operation state of STA 1 may remain in the normal transmit / receive state within the shared TXOP (e.g., within the time allocated by the MU-RTS TXS frame). After the end time of the shared TXOP, STA 1 may transition its operation state from the normal transmit / receive state to the listening state. For example, when AP1 shares a TXOP with STA 1, STA 1 may operate as the TXOP owner within the shared TXOP. Alternatively, STA 1 may operate similarly to the TXOP owner within the shared TXOP. In other words, just as STA 1 acquires a TXOP, STA 1 may operate in the EMLSR mode within the shared TXOP. "STA 1 operates in the EMLSR mode" may mean "STA 1 does not return to the listening state". "STA 1 operates in the EMLSR mode" may mean "STA 1 operates in a state where it can transmit and receive frames (e.g., the normal transmit / receive state)". When STA 1, which is connected to the EMLSR STA MLD 1, acquires a TXOP, STA1 may perform normal transmit / receive operations within the TXOP. In other words, STA 1 may transmit / receive frames within the TXOP.

[0208] For example, STA 1 can receive a MU-RTS TXS frame from AP 1 and send a CTS frame to AP 1 as a response to the MU-RTS TXS frame. In this case, the TXOP of AP 1 can be shared with STA 1. STA 1 can consider obtaining its own TXOP within the shared TXOP (e.g., the time allocated by the MU-RTS TXS frame). STA 1 can operate as the TXOP owner within the shared TXOP. Alternatively, STA 1 can operate similarly to the TXOP owner within the shared TXOP. STA 1 can perform normal send / receive operations within the shared TXOP. STA 1 can send frames to AP 1 and / or another STA within the shared TXOP. When the shared TXOP ends (e.g., expires, is interrupted), STA 1 can transition its operation state from the normal send / receive state to the listening state. The time required for STA 1 to transition its operation state from the normal send / receive state to the listening state can be time Tt (e.g., EMLSR transition delay time, EMLSR padding delay time). STA 1 can send a frame indicating an early interruption of the shared TXOP to AP 1. In this frame, the RDG / More PPDU subfield of the Command and Status (CAS) field in the A control field included in the MAC header can be set to 0. The recipient of this frame can be AP 1. In other words, the shared TXOP can be terminated prematurely. STA 1 can transition its operation state to the listening state within time Tt after receiving a frame (e.g., BA frame) as a response to the frame sent to AP 1. As another method, STA 1 may not have to receive a frame as a response to the frame sent to AP 1. In this case, STA 1 can transition its operation state from the normal send / receive state to the listening state after time Tt (EMLSR transition delay time, EMLSR padding delay time) from the frame's transmission time (e.g., end of transmission).

[0209] AP MLD 1 can send a TXS frame and / or an initial control frame (e.g., MU-RTS frame, MU-RTS trigger frame, MU-RTS TXS frame) to STA 1 of STA MLD 1. Then, AP MLD 1 can send an initial control frame to STA 2 of STA MLD 1 without using the EMLSR link (e.g., the second link) within the shared TXOP indicated by the MU-RTS frame.

[0210] Figure 9 is a timing diagram showing a seventh embodiment of the communication method of the EMLSR STA.

[0211] Reference Figure 9, a wireless local area network can support multi-link operation. AP MLD 1 and / or STA MLD 1 can operate on multiple links (e.g., the first link and the second link). The AP connected to AP MLD 1 operating on the first link can be referred to as AP 1. The AP connected to AP MLD 1 operating on the second link can be referred to as AP 2. The STA connected to STA MLD 1 operating on the first link can be referred to as STA 1. The STA connected to STA MLD 1 operating on the second link can be referred to as STA 2. STA MLD 1 can support EMLSR operation (e.g., MLSR operation). In other words, STA MLD 1 can be an EMLSR STA MLD (e.g., MLSR STA MLD). STA MLD 1 can perform EMLSR operations on multiple links (e.g., the first link and the second link). The STA connected to STA MLD 1 on each link can be referred to as an EMLSR STA. The STA 1 operating on the first link can be referred to as EMLSR STA 1, and the STA 2 operating on the second link can be referred to as EMLSR STA 2.

[0212] The EMLSR STA MLD can initiate or terminate EMLSR operation (or EMLSR mode) by exchanging Enhanced Multi-Link (EML) Operation Mode Notification (OMN) frames with the AP MLD. Before initiating or terminating the EMLSR mode, one of the STAs, STA 1 or STA 2, can perform normal transmit / receive operations and / or listening operations using a transceiver (e.g., a radio) at a preset time. STA 1 and STA 2 may not be able to perform normal transmit / receive operations simultaneously.

[0213] When the EMLSR STA MLD initiates the EMLSR mode by exchanging EML OMN frames, the EMLSR STA MLD can operate in the EMLSR mode on the EMLSR link negotiated between the EMLSR STA MLD and the AP MLD. In other words, the EMLSR STA MLD can perform EMLSR operations on the EMLSR link. In the EMLSR mode, the EMLSR STA MLD (e.g., EMLSR STA) can perform listening operations or normal transmit / receive operations. The EMLSR STA MLD can perform listening operations to receive frames with a predefined format (e.g., initial control frames) on the EMLSR link.

[0214] When receiving an initial control frame, the EMLSR STA MLD can transition all receive radios (e.g., all receive antennas) or all transmit / receive radios (e.g., all transmit / receive antennas) operating on links other than the link on which the initial control frame is received to the link on which the initial control frame is received, and perform normal transmit / receive operations on the link on which the initial control frame is received. In other words, the EMLSR STA MLD can transmit / receive frames with the AP MLD on the link on which the initial control frame is received. When the EMLSR STA MLD wishes to transmit a frame to the AP MLD, the EMLSR STA MLD can transition all radios to one of the EMLSR links and transmit the frame to the AP MLD by using the radios on one link (e.g., all radios).

[0215] STA 1 can perform normal transmit / receive operations and listening operations. The state of performing normal transmit / receive operations can be referred to as the normal transmit / receive state. The state of performing the listening operation can be referred to as the listening state. When performing normal transmit / receive operations, STA 1 can perform transmit / receive operations on all frames. In other words, STA 1 operating in the normal transmit / receive state can communicate on one link (e.g., the first link). When performing the listening operation, STA 1 can only receive frames with a predefined format. In other words, STA 1 operating in the listening state can perform a listening operation to receive frames on the EMLSR link. The frame with a predefined format can be an initial control frame. The initial control frame can be a MU-RTS frame or a BSRP trigger frame.

[0216] When the operating state of STA 1 is the listening state, STA 2 connected to the EMLSR STA MLD 1 can perform the listening operation. When the operating state of STA 1 is the normal transmit / receive state, the operating state of STA 2 connected to the EMLSR STA MLD 1 can be a state where it is unable to transmit / receive. In the state where it is unable to transmit / receive, STA 2 may not be able to transmit / receive frames. When STA 1 transitions from the listening state to the normal transmit / receive state, STA 2 can be in the state where it is unable to transmit / receive. During the time required to transition from the normal transmit / receive state to the listening state (e.g., Tt time), STA 2 can be in the state where it is unable to transmit / receive. The change in the operating state can be similarly applied to STA 1 and STA 2 (e.g., STAs connected to the same EMLSR STA MLD). For example, if STA 2 is in the listening state, STA 1 can be in the listening state. If STA 2 is in the normal transmit / receive state, STA 1 can be in the state where it is unable to transmit / receive.

[0217] On the first link, AP 1 may configure (e.g., obtain, initiate) a TXOP before performing a transmit opportunity (TXOP) sharing operation. When "AP 1 performs the process of exchanging a request to send (RTS) frame and a clear to send (CTS) frame", "AP 1 sends a CTS-to-self frame", and / or "AP 1 sends a data frame", a TXOP may be configured (e.g., obtained, initiated). As another method, AP 1 may configure a TXOP by performing "the operation of sending a TXOP sharing (TXS) operation" and / or "the operation of sending an initial control frame (e.g., MU-RTS frame, MU-RTS trigger frame, MU-RTS TXS frame) and receiving a CTS frame".

[0218] Within the TXOP configured on the first link, AP 1 may send a MU-RTS frame to STA 1 (e.g., EMLSR STA) without performing a channel contention process. The MU-RTS frame may be an initial control frame for EMLSR operation. The MU-RTS frame may be a frame indicating a TXOP sharing operation (e.g., MU-RTS TXS frame). STA 1 may not decode the MU-RTS frame indicating TXOP sharing (e.g., the content of the MU-RTS frame). According to the MU-RTS frame, the MU-RTS frame first sent by AP 1 to STA 1 may be a basic MU-RTS frame that does not indicate TXOP sharing (e.g., TXOP sharing operation) (e.g., a basic variant MU-RTS frame, a MU-RTS frame that is not a TXS frame). The user information field included in the basic MU-RTS frame may indicate the STA (e.g., one STA) that is the recipient of the basic MU-RTS frame. The common information field of the basic MU-RTS frame may not include a triggered TXOP sharing mode subfield. Alternatively, the common information field of the basic MU-RTS frame may include a triggered TXOP sharing mode subfield, and the value of the triggered TXOP sharing mode subfield may be set to 0.

[0219] An EMLSR STA operating in EMLSR mode may receive an initial control frame during a listening operation. In this case, in order to perform a normal transmit / receive operation on the link where the initial control frame is received, the EMLSR STA may change the receive radio from a link other than the link where the initial control frame is received to the link where the initial control frame is received. The time required to change the receive radio may be time Tt. The time required to change from the normal transmit / receive state to the listening state may be time Tt. Time Tt may be an EMLSR transition delay or an EMLSR fill delay.

[0220] The MU-RTS frame as the initial control frame can indicate TXOP sharing. The length of the padding included in the MU-RTS frame should be longer than the length corresponding to the time Tt, where the time Tt is the time required for the operation state of the EMLSR STA to change from the listening state to the normal transmission / reception state. Therefore, in order to make the length of the padding included in the MU-RTS frame equal to or longer than the length corresponding to the time Tt, the MU-RTS frame can include padding bits (e.g., padding bits). STA 1 can receive the MU-RTS frame from AP 1. The padding bits can be bits used to increase the time length of the frame. When receiving the MU-RTS frame of AP 1, STA 1 can change the operation state from the listening state to the normal transmission / reception state.

[0221] STA 1 can send a CTS frame to AP 1 after a short inter-frame space (SIFS) from the reception time (e.g., the reception end time) of the MU-RTS frame of AP 1. STA 1 can confirm that medium access control (MAC) primitives and / or PHY primitives occur during the time Tw from the transmission time (e.g., the transmission end time) of the CTS frame. The operation of STA 1 based on the primitives (e.g., MAC primitives and / or PHY primitives) that occur during the time Tw can be performed based on the following conditions. The time Tw can be aSIFSTime + aSlotTime + aRxPHYStartDelay.

[0222] AP 1 can receive the CTS frame from STA 1 and send a second MU-RTS frame to STA 1. The second MU-RTS frame can be sent within the time Tw. STA 1 can receive the second MU-RTS frame of AP 1. When receiving the second MU-RTS frame of AP 1, STA 1 (e.g., the PHY layer of STA1) can generate a PHY-RXSTART.indication primitive. In this case, the following condition 0 is satisfied, so STA 1 can maintain the normal transmission / reception state. In other words, STA1 can not change the operation state from the normal transmission / reception state to the listening state.

[0223] - Condition 0: The PHY-RXSTART.indication primitive appears at the PHY layer of STA 1 within the time Tw.

[0224] The second MU-RTS frame of AP 1 can be a frame (e.g., MU-RTS TXS frame) indicating TXOP sharing (e.g., TXOP sharing operation). The TXOP sharing operation can be a triggered TXOP sharing operation. For example, AP 1 can share a part or all of the TXOP with STA 1. The TXOP sharing mode can be 1 or 2. The TXOP sharing mode can indicate that "STA 1 can perform uplink communication for AP 1". The TXOP sharing mode 2 can indicate that "STA 1 can perform uplink communication for AP 1 and / or communication for another STA (e.g., direct communication, P2P communication)".

[0225] STA 1 can decode the MU-RTS frame of AP 1 and confirm that AP 1 performs TXOP sharing based on the decoding result (e.g., information element (e.g., field) included in the MU-RTS frame). For example, STA 1 can identify the time indicated by the allocated duration subfield of the MU-RTS frame and identify the TXOP length shared by AP 1 based on the identified time. The shared TXOP length or / and the shared TXOP can be referred to as the time allocated by the MU-RTS TXS trigger frame. STA 1 can send a CTS frame to AP 1 after a short interframe space (SIFS) from the reception time (e.g., reception end time) of the MU-RTS frame of AP 1. STA 1 can confirm that a media access control (MAC) primitive and / or a PHY primitive occurs during a time Tw from the transmission time (e.g., transmission end time) of the CTS frame. The operation of STA 1 based on the primitive (e.g., MAC primitive and / or PHY primitive) occurring during the time Tw can be performed based on the following conditions. The time Tw can be aSIFSTime + aSlotTime + aRxPHYStartDelay.

[0226] If one or more of the following conditions are satisfied during the time Tw, STA 1 may not change the operation state from the normal transmit / receive state to the listening state.

[0227] - Condition 1: The PHY-RXSTART.indication primitive appears in the PHY layer of STA 1.

[0228] - Condition 2: The MAC layer of STA 1 passes the PHY-RXSTART.indication primitive to the PHY layer of STA 1, and the PHY layer passes the PHY-TXSTART.confirm primitive to the MAC layer as a response to a request (e.g., PHY-TXSTART.request primitive).

[0229] If neither Condition 1 nor Condition 2 is satisfied, STA 1 may change its operation state from the normal transmission / reception state to the listening state. Each of Condition 1 and Condition 2 may be a state retention condition (or a state transition condition). If the state retention condition (e.g., at least one state retention condition) is satisfied within a preset time (e.g., time Tw), STA 1 may maintain its current operation state (e.g., the normal transmission / reception state). If the state retention condition (e.g., all state retention conditions) is not satisfied within a preset time (e.g., time Tw), STA 1 may change its current operation state. In this document, STA 1 may change its operation state from the normal transmission / reception state to the listening state. Condition 1 may represent "the condition for STA 1 to receive a frame from another communication node (e.g., AP 1 or another STA)". Condition 2 may represent "the condition that a frame to be transmitted to another communication node (e.g., AP 1 or another STA) appears at STA 1".

[0230] STA 1 may transmit frames within a shared TXOP. Within the shared TXOP, STA 1 may perform the same operations or similar operations as the STA in the Figures 3 to 8 embodiments (e.g., STA MLD 1, STA 1).

[0231] AP MLD 1 may send a TXS frame and / or an initial control frame (e.g., MU-RTS frame, MU-RTS trigger frame, MU-RTS TXS frame) to STA 1 of STA MLD 1. Then, AP MLD 1 may not send an initial control frame to STA 2 of STA MLD 1 by using the EMLSR link (e.g., the second link) within the shared TXOP indicated by the MU-RTS frame.

[0232] The operations of the method according to an exemplary embodiment of the present invention may be implemented as a computer-readable program or code in a computer-readable recording medium. The computer-readable recording medium may include all types of recording devices that store data readable by a computer system. In addition, the computer-readable recording medium may store and execute programs or codes, and these programs or codes may be distributed in computer systems connected through a network and read by a computer in a distributed manner.

[0233] In addition, the computer-readable recording medium may include a hardware device specifically configured to store and execute program instructions, such as ROM, RAM, or flash memory. The program instructions may include not only machine language codes created by a compiler but also high-level language codes executable by a computer using an interpreter.

[0234] Although some aspects of the present invention have been described in the context of apparatus, these aspects may indicate corresponding descriptions according to the method, and the blocks or apparatus may correspond to the steps of the method or the features of the steps. Similarly, aspects described in the context of the method may be represented as the features of the corresponding blocks or items or corresponding apparatus. Some or all of the steps of the method may be performed by (or using) a hardware apparatus such as a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, one or more of the most important steps of the method may be performed by such an apparatus.

[0235] In some exemplary embodiments, a programmable logic device (e.g., a field programmable gate array) may be used to perform some or all of the functions of the methods described herein. In some exemplary embodiments, a field programmable gate array may be operated with a microprocessor to perform one of the methods described herein. Generally, the methods are preferably performed by a specific hardware apparatus.

[0236] While the present invention has been described above with reference to preferred embodiments of the present invention, those skilled in the art will understand that various modifications and variations can be made to the present invention without departing from the scope and spirit of the present invention as defined by the appended claims.

Claims

1. A method for a first Station (STA), the method comprising: Operating in a listening state on a first link; Receiving an initial control frame from a first Access Point (AP) on the first link; After receiving the initial control frame, changing the operating state of the first STA from the listening state to a normal transmit / receive state; Determining whether one or more state retention conditions are satisfied within a preset time; And Based on whether one or more state retention conditions are satisfied, maintaining or changing the operating state of the first STA.

2. The method according to claim 1, wherein, The one or more state retention conditions include at least one of a first condition or a second condition, the first condition being "the condition that the first STA receives a frame from another communication node", and the second condition being "the condition that a frame to be transmitted to another communication node appears in the first STA".

3. The method according to claim 1, wherein The one or more state retention conditions include at least one of a first condition or a second condition, the first condition indicating that "the PHY-RXSTART.indication primitive appears in the Physical (PHY) layer of the first STA", and the second condition indicating that "the Medium Access Control (MAC) layer of the first STA passes the PHY-TXSTART.request primitive to the PHY layer of the first STA, and the PHY layer of the first STA passes the PHY-TXSTART.confirm primitive to the MAC layer as a response to the PHY-TXSTART.request primitive".

4. The method according to claim 1, wherein When the one or more state retention conditions are satisfied, the first STA maintains the normal transmit / receive state, and when the one or more state retention conditions are not satisfied, the first STA changes the operating state from the normal transmit / receive state to the listening state.

5. The method according to claim 1, wherein The initial control frame indicates Transmission Opportunity (TXOP) sharing, and the first STA operating in the normal transmit / receive state performs communication within the shared TXOP according to TXOP sharing.

6. The method according to claim 5, wherein, When the mode of TXOP sharing is TXOP sharing mode 1, the first STA performs communication with the first AP within the shared TXOP, and when the mode of TXOP sharing is TXOP sharing mode 2, the first STA performs communication with at least one of the first AP or another STA within the shared TXOP.

7. The method according to claim 1, further comprising receiving a Multi-User (MU)-Request To Send (RTS) frame indicating TXOP sharing from the first AP in the normal transmit / receive state; Among them, The first STA operating in the normal transmit / receive state performs communication within the shared TXOP according to TXOP sharing.

8. The method according to claim 1, further comprising sending a Clear To Send (CTS) frame to the first AP on the first link as a response to the initial control frame; Among them, The preset time starts from the end time of the transmission of the CTS frame.

9. The method according to claim 8, wherein, The preset time is aSIFSTime + aSlotTime + aRxPHYStartDelay.

10. The method according to claim 1, wherein, In the listening state, the first STA performs a listening operation to receive frames on one or more Enhanced Multi-Link Single-Radio (EMLSR) links, and in the normal transmit / receive state, the first STA performs communication on one link.

11. A first Station (STA) comprising at least one processor, Among them, wherein the at least one processor causes the first STA to: operate in a listening state on a first link; receive an initial control frame from a first Access Point (AP) on the first link; after receiving the initial control frame, transition the operating state of the first STA from the listening state to the normal transmit / receive state; determine whether one or more state retention conditions are satisfied within a preset time; and retain or transition the operating state of the first STA based on whether one or more state retention conditions are satisfied.

12. The first STA according to claim 11, wherein, The one or more state retention conditions include at least one of a first condition or a second condition, the first condition being "the condition that the first STA receives a frame from another communication node", and the second condition being "the condition that a frame to be transmitted to another communication node appears in the first STA".

13. The first STA according to claim 11, wherein, The one or more state retention conditions include at least one of a first condition or a second condition, the first condition indicating that "the PHY-RXSTART.indication primitive appears in the Physical (PHY) layer of the first STA", and the second condition indicating that "the Medium Access Control (MAC) layer of the first STA passes the PHY-TXSTART.request primitive to the PHY layer of the first STA, and the PHY layer of the first STA passes the PHY-TXSTART.confirm primitive to the MAC layer as a response to the PHY-TXSTART.request primitive".

14. The first STA according to claim 11, wherein, When one or more state retention conditions are satisfied, the first STA retains the normal transmit / receive state, and when one or more state retention conditions are not satisfied, the first STA transitions the operating state from the normal transmit / receive state to the listening state.

15. The first STA according to claim 11, wherein, The initial control frame indicates Transmission Opportunity (TXOP) sharing, and the first STA operating in the normal transmit / receive state performs communication within the shared TXOP according to TXOP sharing.

16. The first STA according to claim 15, wherein, When the mode of TXOP sharing is TXOP sharing mode 1, the first STA performs communication with the first AP within the shared TXOP, and when the mode of TXOP sharing is TXOP sharing mode 2, the first STA performs communication with at least one of the first AP or another STA within the shared TXOP.

17. The first STA according to claim 11, wherein The at least one processor further causes the first STA to receive a Multi-User (MU)-Request To Send (RTS) frame indicating TXOP sharing from the first AP in the normal transmit / receive state; wherein the first STA operating in the normal transmit / receive state performs communication within the shared TXOP according to TXOP sharing.

18. The first STA according to claim 11, wherein, The at least one processor further causes the first STA to send a Clear To Send (CTS) frame to the first AP on the first link as a response to the initial control frame; and Among them, the preset time starts from the end time of the transmission of the CTS frame.

19. The first STA according to claim 18, wherein, The preset time is aSIFSTime + aSlotTime + aRxPHYStartDelay.

20. The first STA according to claim 11, wherein, In the listening state, the first STA performs a listening operation to receive frames on one or more Enhanced Multi-Link Single Radio (EMLSR) links, and in the normal transmit / receive state, the first STA performs communication on one link.

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