Method and device for performing DPS operation in wireless LAN

Abstract

In a wireless LAN system, a first STA operates on the basis of LCM, wherein the first STA is an STA which performs operation mode switching on the basis of DPS, operates by switching an operation mode from LCM to HCM, and switches the operation mode from HCM to LCM when a switching condition is satisfied in HCM for a first preset time from a first time point.

Description

Method and device for performing DPS operation in wireless LAN

[0001] The present disclosure relates to a method and apparatus for performing reverse transmission and transmit opportunity (TXOP) sharing when dynamic power saving (DPS) operation is supported in a wireless local area network (WLAN). Additionally, the present disclosure relates to a method and apparatus for a wireless LAN terminal supporting DPS operation to share a TXOP.

[0002]

[0003] With the recent expansion of mobile device adoption, Wireless Local Area Network (WLAN) technology, capable of providing fast wireless communication services to these devices, is receiving significant attention. Based on short-range wireless communication technology, WLAN technology enables mobile devices such as smartphones, smart pads, laptop computers, portable multimedia players, and embedded devices to connect to the internet wirelessly.

[0004] Standards using wireless LAN technology are primarily developed by the IEEE (Institute of Electrical and Electronics Engineers) as the IEEE 802.11 standard. As the aforementioned wireless LAN technology has been developed and disseminated, applications utilizing wireless LAN technology have diversified, and a demand has arisen for wireless LAN technology that supports higher reliability.

[0005] As applications requiring higher reliability emerge, the IEEE 802.11bn standard, an Ultra High Reliability (UHR) wireless LAN technology, is being developed for single Basic Service Set (BSS) environments and / or redundant BSS environments. The goal of the IEEE 802.11bn standard may be to support improved data transmission speeds, enhanced latency performance, and reduced data error rates. Additionally, the IEEE 802.11bn standard can support low-power operation, peer-to-peer communication, and operations designed to increase channel utilization. It can also support a TXOP sharing method, where wireless LAN terminals share communication resources called TXOPs (transmit opportunities) between access points (APs). Furthermore, to increase the efficiency of communication resource utilization, the wireless LAN standard can support non-primary channel access (NPCA) operations, which use a channel other than the primary channel when the primary channel is occupied, and dynamic subchannel operation (DSO). In addition, dynamic power saving (DPS) can be supported to improve the power saving performance of wireless LAN terminals. The following describes a method in which a wireless LAN terminal supporting DPS in a wireless LAN shares a transmission opportunity and performs reverse transmission in accordance with the above.

[0006] Meanwhile, the technology forming the background of the invention is written to enhance understanding of the background of the invention and may include content that is not prior art already known to a person with ordinary knowledge in the field to which this technology belongs.

[0007]

[0008] The present disclosure relates to a method and apparatus for performing reverse transmission and TXOP sharing when DPS operation is supported in a wireless LAN.

[0009] The present disclosure relates to a method and apparatus for a wireless LAN terminal supporting DPS operation to share a TXOP.

[0010] The present disclosure relates to a method and apparatus for a wireless LAN terminal to switch its operating mode from a lower capability mode (LCM) to a higher capability mode (HCM) when DPS operation and TXOP sharing (TXS) are performed together.

[0011] The present disclosure relates to a method and apparatus for a wireless LAN terminal supporting DPS operation to maintain HCM without switching to LCM in a section where TXOP is shared.

[0012] The technical problems to be solved in this disclosure are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which this disclosure belongs from the description below.

[0013]

[0014] According to one embodiment of the present specification, a method of operation of a first station (STA) in a wireless LAN system comprises the step of the first STA operating based on a lower capability mode (LCM), wherein the first STA is a STA that performs a mode switching based on dynamic power saving (DPS), and the step of the first STA switching its mode of operation from LCM to a higher capability mode (HCM), wherein the first STA receives a transmit opportunity (TXOP) acquired by the second STA from the second STA, and the step of switching the mode of operation from HCM to LCM when a switching condition is satisfied for a first predetermined time from a first time point after the first STA has switched its mode of operation to HCM, wherein the first STA may maintain HCM until the switching condition is satisfied in the shared TXOP.

[0015] Additionally, according to one embodiment of the present specification, a station (STA) in a wireless LAN system comprises at least one transceiver for transmitting and receiving signals, at least one processor for controlling at least one transceiver, and a memory for storing instructions that cause a non-AP STA to perform a specific operation by the at least one processor, wherein the specific operation is: operated based on a lower capability mode (LCM), wherein the first STA is a STA that performs an operation mode switching based on dynamic power saving (DPS), and operates by switching the operation mode from LCM to a higher capability mode (HCM), wherein the STA shares a TXOP acquired by another STA from another STA, and, after switching the operation mode to HCM, if a switching condition is satisfied for a first predetermined time from a first point in time, the operation mode is switched from HCM to LCM, wherein the STA may maintain HCM until the switching condition is satisfied in the shared TXOP.

[0016] In addition, the following points may apply in common.

[0017] According to one embodiment of the present specification, the first time point may include at least one of the time point when the first STA completes transmitting a response frame for a frame received from another STA, the time point when the first STA completes receiving a frame that does not require an immediate response from another STA, and the time point when the first STA completes transmitting a frame that does not require an immediate response.

[0018] In addition, according to one embodiment of the present specification, if the first STA does not detect frame reception for a first set time from a first time point, does not perform frame transmission, does not have a nonempty transmit queue, and does not schedule frame transmission, the switching condition is satisfied and the operating mode can be switched from HCM to LCM.

[0019] Additionally, according to one embodiment of the present specification, the operation mode can be switched from HCM to LCM in any one of the following cases: when the first STA detects the reception of a frame for a first set time from a first time point but the recipient of the frame is not the first STA; when the first STA detects the reception of a trigger frame for a first set time from a first time point but the trigger frame does not allocate resources to the first STA; and when the first STA detects the reception of a CTS (clear to send) frame for a first set time from a first time point but the recipient address of the CTS frame is not the address of the access point (AP) connected to the first STA.

[0020] In addition, according to one embodiment of the present specification, when the first STA switches the operation mode from HCM to LCM, the operation mode switching is performed during the mode switching time after the first set time has elapsed from the first point in time, so that it can operate as HCM after the mode switching time.

[0021] Additionally, according to one embodiment of the present specification, when the first STA receives an initial control frame (ICF) from the second STA that has acquired a TXOP, it switches the operation mode from LCM to HCM and transmits an initial control response (ICR). When the second STA shares the TXOP acquired by the second STA, the first STA may maintain the HCM from a first time point until a first set time is satisfied.

[0022] In addition, according to one embodiment of the present specification, when the first STA receives an ICF from the second STA that has acquired a TXOP, it switches the operation mode from LCM to HCM and transmits an ICR, and when it receives a trigger frame that allocates uplink resources from the second STA and performs frame transmission to the second STA, the first STA may maintain HCM from a first time point until a first set time is satisfied.

[0023] Additionally, according to one embodiment of the present specification, the first STA receives a first frame that shares a TXOP from a second STA that has acquired a TXOP from an LCM, wherein the first frame is redundantly transmitted in at least one bandwidth including the bandwidth in which the first STA operates based on the LCM, and the first STA receives a shared TXOP acquired by the second STA based on the first frame, and after transmitting a second frame as a response frame to the first frame, can perform data frame transmission.

[0024] Additionally, according to one embodiment of the present specification, the first frame includes total bandwidth information in which the first frame is transmitted, and the first STA can transmit a second response frame as a response frame to the first frame and then perform data frame transmission based on the total bandwidth information included in the first frame.

[0025] Additionally, according to one embodiment of the present specification, a second frame transmitted by the first STA includes an operation mode indicator, and after transmitting the second frame, the first STA switches the operation mode from LCM to HCM, and the TXOP shared with the first STA may be retained without being retrieved for a preset time based on the operation mode switching of the first STA.

[0026] In addition, according to one embodiment of the present specification, the second frame transmitted by the first STA includes a padding field based on the operation mode switching of the first STA, and the first STA can perform frame transmission and reception in a shared TXOP by switching the operation mode from LCM to HCM before the transmission of the second frame is completed.

[0027] In addition, according to one embodiment of the present specification, a first frame received by a first STA includes a padding field based on the operation mode switching of the first STA, and the first STA can switch the operation mode from LCM to HCM before the reception of the first frame is completed and perform frame transmission and reception in a shared TXOP.

[0028] Additionally, according to one embodiment of the present specification, the first STA receives an ICF containing padding fields from the LCM before receiving the first frame, switches the operation mode from the LCM to the HCM until the reception of the ICF is complete, and after transmitting an ICR in response to the ICF from the HCM, receives the first frame, it can receive a shared TXOP from the second STA.

[0029] Additionally, according to one embodiment of the present specification, the first frame may be a MU-RTS TXS (multi-user-request to send TXOP sharing) trigger frame, and the second frame may be a CTS (clear to send) frame.

[0030] In addition, according to one embodiment of the present specification, in an LCM based on DPS operation, at least one of the operation bandwidth, the number of operation space streams and the modulation and coding scheme (MCS) may be limited or only the reception of an initial control frame may be possible, and in an HCM based on DPS operation, general transmission and reception operations may be possible.

[0031] Additionally, according to one embodiment of the present specification, the first STA may be a non-AP STA or an AP STA.

[0032]

[0033] According to the present disclosure, a method for performing reverse transmission and TXOP sharing can be provided when DPS operation is supported in a wireless LAN.

[0034] According to the present disclosure, a wireless LAN terminal supporting DPS operation can provide a method for sharing TXOP.

[0035] According to the present disclosure, a method can be provided for a wireless LAN terminal to switch its operation mode from LCM to HCM when DPS operation and TXS are performed together.

[0036] According to the present disclosure, a wireless LAN terminal supporting DPS operation can provide a method to maintain HCM without switching to LCM in a section where TXOP is shared.

[0037] The technical problems to be solved in this disclosure are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which this disclosure belongs from the description below.

[0038] The effects obtainable from the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below.

[0039]

[0040] FIG. 1 is a diagram showing a communication node within a wireless LAN system to which the present disclosure applies.

[0041] FIG. 2 is a drawing showing a wireless LAN system to which the present disclosure is applied.

[0042] FIG. 3 is a diagram illustrating a dynamic power saving operation method applied to the present disclosure.

[0043] FIG. 4 is a diagram illustrating a dynamic low-power operation method during reverse transmission in a wireless LAN network to which the present disclosure applies.

[0044] FIG. 5 is a diagram illustrating a dynamic low-power operation method during reverse transmission in a wireless LAN network to which the present disclosure applies.

[0045] FIG. 6 is a diagram illustrating a dynamic low-power operation method during reverse transmission in a wireless LAN network to which the present disclosure applies.

[0046] FIG. 7 is a diagram illustrating a dynamic power saving method applied to the present disclosure.

[0047] FIG. 8 is a diagram illustrating a TXS operation method of a wireless LAN terminal applicable to the present disclosure.

[0048] FIG. 9 is a diagram showing the TXS operation method of a wireless LAN dynamic power saving terminal applied to the present disclosure.

[0049] FIG. 10 is a diagram showing the TXS operation method of a wireless LAN dynamic power saving terminal applied to the present disclosure.

[0050] FIG. 11 is a diagram showing the TXS operation method of a wireless LAN dynamic power saving terminal applied to the present disclosure.

[0051] FIG. 12 is a diagram showing the TXS operation method of a wireless LAN dynamic power saving terminal applied to the present disclosure.

[0052] FIG. 13 is a diagram showing the TXS operation method of a wireless LAN dynamic power saving terminal applied to the present disclosure.

[0053] FIG. 14 is a diagram showing the TXS operation method of a wireless LAN dynamic power saving terminal applied to the present disclosure.

[0054] FIG. 15 is a flowchart showing the operation of a STA in a wireless LAN to which the present disclosure applies.

[0055]

[0056] The present disclosure is capable of various modifications and may have various embodiments, and specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present disclosure to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the present disclosure.

[0057] Terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms. Such terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present disclosure, the first component may be named the second component, and similarly, the second component may be named the first component. The term "and / or" includes a combination of a plurality of related described items or any of a plurality of related described items.

[0058] When it is stated that one component is "connected" or "connected" to another component, it should be understood that while it may be directly connected or connected to that other component, there may also be other components in between. On the other hand, when it is stated that one component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between.

[0059] The terms used in this disclosure are used merely to describe specific embodiments and are not intended to limit this disclosure. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this disclosure, terms such as “comprising” or “having” are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0060] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which this disclosure pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this disclosure.

[0061] Hereinafter, preferred embodiments of the present disclosure will be described in more detail with reference to the attached drawings. In order to facilitate an overall understanding of the present disclosure, the same reference numerals are used for identical components in the drawings, and redundant descriptions of identical components are omitted.

[0062] Below, a wireless communication system to which embodiments according to the present disclosure are applied will be described. The wireless communication system to which embodiments according to the present disclosure are applied is not limited to the details described below, and embodiments according to the present disclosure may be applied to various wireless communication systems. The wireless communication system may be referred to as a "wireless communication network."

[0063] FIG. 1 is a diagram showing a communication node within a wireless LAN system to which the present disclosure applies. Referring to FIG. 1, the communication node (100) may include at least one of a processor (110), memory (120), a transceiver (130), an input / output interface (140), a storage device (150), and a bus (160). For example, the communication node (100) may be an access point (AP), a station (STA), an access point multi-link device (MLD), or a non-AP MLD. However, the communication node may not be limited thereto and may be a node that performs communication with another node or device based on the configuration described above. For example, the operating channel bandwidth supported by the AP may be 20 MHz (megahertz), 80 MHz, 160 MHz, etc. The operating channel bandwidth supported by the station may be 20 MHz, 80 MHz, etc. However, it may not be limited thereto.

[0064] A processor (110) within a communication node (100) can control at least one of a memory (120), a transceiver (130), an input / output interface (140), and a storage device (150) for each component within the communication node. The memory (120) within the communication node (100) can store information regarding commands and instructions executed by the processor (110), and the transceiver (130) may refer to a transceiver, an RF (radio frequency) unit, an RF module, or other components that perform signal transmission and reception. The input / output interface (140) within the communication node (100) is an interface for input and output that can be linked with other interfaces and may further include a separate storage device (150). Each component within the communication node (100) can communicate with one another by being connected by a bus (160).

[0065] However, as an example, each component included in the communication node (100) may be connected via an individual interface or an individual bus centered on the processor (110), rather than via a common bus (160). The processor (1110) may also be connected via a dedicated interface to at least one of the memory (120), the transmission / reception device (130), the input / output interface device (140), and the storage device (150).

[0066] A processor (110) can execute a program command stored in at least one of a memory (120) or a storage device (150). The processor (110) may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present disclosure are performed. Each of the memory (120) and the storage device (150) may be composed of at least one of a volatile storage medium or a non-volatile storage medium. e.g., the memory (120) may be composed of at least one of read-only memory (ROM) or random access memory (RAM).

[0067] In the following, the relevant operations are described based on the wireless LAN terminal as a station (STA). In accordance with the terminology usage according to IEEE 802.11, STA can refer to both AP STAs operating as access points (APs) and non-AP STAs operating in connection with an AP. However, for the convenience of explanation, APs and non-AP STAs are distinguished below; this distinction is merely for convenience of explanation, and it is self-evident that operations regarding an AP can be applied to both AP STAs and non-AP STAs. Furthermore, it is self-evident that the non-AP STA operations described below can also be applied to both non-AP STAs and AP STAs.

[0068] FIG. 2 is a diagram illustrating a wireless LAN system to which the present disclosure applies. Referring to FIG. 2, the basic service set (BSS) of the wireless LAN system may include one AP (210) and a plurality of non-AP STAs (221, 222, 223, 224), and the plurality of non-AP STAs (221, 222, 223, 224) may be controlled by the AP (210). However, the wireless LAN system is not limited to a BSS, and an environment consisting only of non-AP STAs without a fixed service set or AP may also be considered, and is not limited to a specific form. Each wireless device within the wireless LAN system may include a MAC (medium access control) layer and a physical (PHY) layer, and communication between wireless devices may be performed. For convenience of explanation, the following description focuses on the AP and non-AP STA, but is not limited thereto. For example, the following items may apply equally to other communication nodes or devices and are not limited to a specific form.

[0069] There may be cases where DPS operation, reverse communication, and TXOP sharing methods are applied together in a wireless LAN, and a method considering the above-mentioned cases may be required. Based on the above, when a wireless LAN terminal receives a shared TXOP, a method for maintaining the shared TXOP as an HCM may be required, and the operation based on this is described below. As described above, DPS operation and TXS operation can be performed smoothly.

[0070] FIG. 3 is a diagram illustrating a dynamic power saving operation method applied to the present disclosure. Referring to FIG. 3, the description is based on AP 1 (310) and a non-AP STA 1 that is connected (associated) with AP 1 in a wireless LAN network, but this is for convenience of explanation only and is not limited thereto.

[0071] In a wireless LAN network, at least one of AP 1 (310) and non-AP STA 1 (320) may perform dynamic power saving (DPS). Dynamic power saving may be dynamic low-power operation. The power saving mode that can be operated during dynamic power saving may be a lower capability mode (LCM) with fewer restrictions than a doze mode. In LCM, at least one of the operating bandwidth, number of spatial streams, and modulation and coding scheme (MCS) index may be limited in at least one of AP 1 (310) and non-AP STA 1 (320). That is, at least one of AP 1 (310) and non-AP STA 1 (320) may perform transmission and reception of frames with the operating bandwidth, number of spatial streams, and MCS index of LCM as upper limits. Meanwhile, the AP performing the DPS operation may be a mobile AP or an AP included in a mobile AP MLD, but is not limited thereto.

[0072] Alternatively, at least one of AP 1 (310) and non-AP STA 1 (320) may be able to receive only frames of a specific format in the LCM. The frame of a specific format may be an initial control frame (ICF), but is not limited thereto. The initial control frame may be at least one of a BlockAck request (BAR) frame, a request to send (MU) trigger frame, a buffer status report poll (BSRP) trigger frame, and other frames, and is not limited to a specific form. Additionally, as an example, at least one of AP 1 (310) and non-AP STA 1 (320) may be able to transmit and receive frames other than ICF in the LCM based on communication parameters available in the LCM operation mode.

[0073] Additionally, at least one of AP 1 (310) and non-AP STA 1 (320) may operate in a higher capability mode (HCM). When at least one of AP 1 (310) and non-AP STA 1 (320) operates in HCM, at least one of AP 1 (310) and non-AP STA 1 (320) may be capable of general data transmission and reception, and the operating bandwidth, spatial stream, and MCS index may not be limited in at least one of AP 1 (310) and non-AP STA 1 (320). That is, based on the terminal capability of at least one of AP 1 (310) and non-AP STA 1 (320), transmission and reception of frames may be possible within the upper limit of communication parameters according to the terminal operation capability limit. Power consumption is lowest when at least one of AP 1 (310) and non-AP STA 1 (320) operates in Doze mode, and power consumption may be highest when operating in HCM mode.

[0074] Meanwhile, as described above, the mode in which the AP and STA performing dynamic power saving operations perform power saving operations may be Doze mode or LCM. The mode in which the AP and STA performing dynamic power saving operations cannot (or do not) perform power saving operations may be HCM. Accordingly, in the present disclosure, when an STA (including AP and non-AP STA) using dynamic power saving operations switches the operation mode from HCM to LCM, it may mean switching from an "operation mode in which power saving operations cannot (do not) perform" to a "mode in which power saving operations are performed." Additionally, when an operation mode switches from LCM to HCM, it may mean switching from a "mode in which power saving operations are performed" to an "operation mode in which power saving operations cannot (do not) perform".

[0075] At least one of AP 1 (310) and non-AP STA 1 (320) operating as DPS may receive an ICF in LCM. When at least one of AP 1 (310) and non-AP STA 1 (320) receives an ICF, at least one of AP 1 (310) and non-AP STA 1 (320) may operate as HCM. Here, at least one of AP 1 (310) and non-AP STA 1 (320) may require a separate transition time or switch time to switch from LCM to HCM. For example, the separate transition time or switch time for switching from LCM to HCM may be included in a padding field in the ICF. The padding field may be a field that extends the time length of the frame and ensures the aforementioned transition time or switch time. Thus, the length of the padding field may correspond to or be greater than the transition time or switch time. At least one of AP 1 (310) and non-AP STA 1 (320) may receive an ICF and operate as HCM, and transmit an initial control response (ICR) frame (which may be abbreviated as ICR). When the ICF and ICR exchange procedure is completed, at least one of AP 1 (310) and non-AP STA 1 (320) operating as HCM may complete frame transmission and reception. At least one of AP 1 (310) and non-AP STA 1 (320) may switch back from HCM to LCM when frame transmission and reception is completed. Here, a separate transition time or switching time may be required to switch operation from HCM to LCM. For example, at least one of AP 1 (310) and non-AP STA 1 (320) may have at least one of the operation bandwidth, spatial stream number, and MCS index limited during the corresponding transition time or switching time.Alternatively, at least one of AP 1 (310) and non-AP STA 1 (320) may be able to receive only frames of a specific format (e.g., ICF) during the corresponding transition time or switching time. Alternatively, at least one of AP 1 (310) and non-AP STA 1 (320) may be able to transmit only frames of a specific format (e.g., ICF) during the corresponding transition time or switching time, but is not limited thereto.

[0076] The following describes a frame exchange method based on DPS operation. For example, non-AP STA 1 (320) can perform a DPS operation. Here, AP 1 (310) can perform a channel access operation. The channel access operation may be an enhanced distributed channel access (EDCA) operation, and if the channel access operation is successful, AP 1 (310) can acquire a transmit opportunity (TXOP), which is a time interval during which a frame can be transmitted. The TXOP can be acquired from the entire bandwidth available to AP 1 (310) (e.g., 40 MHz, 80 MHz, 160 MHz, 320 MHz, etc.). However, since non-AP STA 1 (320) operates as an LCM based on the DPS operation, the receiving bandwidth of non-AP STA 1 (320) may be limited (e.g., limited to 20 MHz). AP 1 (310) can transmit an ICF duplicated in 20 MHz increments to non-AP STA 1 (320) so that non-AP STA 1 (320) can receive frames and occupy the entire bandwidth of the TXOP acquired by AP 1 (310). The ICF duplicated in 20 MHz increments can be duplicated and transmitted for the bandwidth of the TXOP acquired by AP 1 (310). Here, AP 1 (310) can instruct the non-AP STA 1 (320) with bandwidth information through the ICF. The bandwidth information may be instructed by at least one of the bandwidth signaling TA (transmitter address) set in the TA (transmitter address) of the MAC header included in the ICF and the L-SIG field of the PHY preamble, or by a combination of the information described above, and is not limited to a specific form.

[0077] Additionally, the format of the ICF may be a Non-HT (high throughput) Duplicate PPDU format. For example, the ICF may be a trigger frame (e.g., a BSRP (buffer status report poll) trigger frame, a MU-RTS (multi-user request to send) trigger frame). The ICF may include a padding field that guarantees a switching time that allows non-AP STA 1 (320) to operate from LCM to HCM. Upon receiving the ICF, non-AP STA 1 (320) can switch the operating mode from LCM to HCM. After switching the operating mode to HCM, non-AP STA 1 (320) can send an ICR to AP 1 (310). Then, AP 1 (310) can send a data frame to non-AP STA 1 (320). Since non-AP STA 1 (320) operates as an HCM, AP 1 (310) can transmit data frames in the full bandwidth, full spatial stream, and full frame format supported by non-AP STA 1 (320). non-AP STA 1 (320) can receive data frames from AP 1 (310) and can also transmit a response frame (e.g., a BlockAck frame). When non-AP STA 1 (320) completes receiving a frame from AP 1 (310) and the frame is a frame that does not require a response frame (or, when non-AP STA 1 (320) completes receiving a frame from AP 1 (310) and completes transmitting a response frame by requesting a response frame), non-AP STA 1 (320) may wait for the next frame received from AP 1 (310) for a certain waiting time (e.g., aSIFSTime + aSlotTime + aRxPHYStartDelay time). The aforementioned certain waiting time may be referred to as Tw time. If no frame is detected during Tw time (e.g.,(where the PHY-RXSTART.indication primitive does not occur), non-AP STA 1 (320) can switch the operation mode from HCM to LCM. The operation described above may be referred to as the end of HCM operation, but is not limited to such terms or names. Additionally, when non-AP STA 1 (320) switches from HCM to LCM, a separate switching time may occur. The separate switching time described above may be referred to as the switching back time, and the switching back time may be referred to as Tt, but is not limited to such terms or names.

[0078] The non-AP STA 1 (320) may operate as an LCM after a transition time Tt. During the transition time that occurs when the non-AP STA 1 (320) transitions from an HCM to an LCM, the non-AP STA 1 (320) may also receive a frame that is receivable in the LCM (e.g., a frame in which at least one of the bandwidth, spatial stream, or format is limited or fixed). The above-described operation may be applied in the same or similar way when the non-AP STA 1 (320) performs frame transmission to the AP 1 (310).

[0079] Here, the aforementioned Tw time is the following<Tw 조건 1> ,<Tw 조건 2> and<Tw 조건 3> It can start if one of the cases is satisfied.

[0080] <Tw 조건 1>

[0081] If the PPDU (physical protocol data unit) transmitted by the STA is a response to the most recently received frame from the AP, it starts at the time the transmission of the PPDU is completed.

[0082]

[0083] <Tw 조건 2>

[0084] If the PPDU received from an AP or another STA contains a frame that does not require an immediate response, start at the time the reception of the PPDU is complete.

[0085]

[0086] <Tw 조건 3>

[0087] If the PPDU transmitted by the STA contains a frame that does not require an immediate response, it starts at the time the transmission of the PPDU is completed.

[0088]

[0089] non-AP STA 1 (320) performs the following for the duration of Tw when Tw is initiated after the completion of reception of the initial control frame<LCM 전환> If the conditions are met, it no longer operates as an HCM and can be switched to an LCM.

[0090]

[0091] <LCM 전환>

[0092] 1) The MAC layer of STA 1 does not receive the PHY-RXSTART.indication primitive from the PHY layer, 2) The MAC layer of STA 1 does not send the PHY-TXSTART.request primitive to the PHY layer, and the MAC layer does not receive the PHY-TXSTART.confirm primitive from the PHY layer, 3) There is no nonempty transmit queue in STA 1, 4) STA 1 does not intend to transmit a frame or schedule a transmission, and, 5) STA 1 is not already transmitting a frame.

[0093]

[0094] The aforementioned<LCM 전환> Under the conditions, the MAC layer of non-AP STA 1 (320) receiving the PHY-RXSTART.indication primitive from the PHY layer may mean that non-AP STA 1 (320) detects a frame being received. Additionally, the MAC layer of non-AP STA 1 (320) sending the PHY-TXSTART.request primitive to the PHY layer and the MAC layer of non-AP STA 1 (320) receiving the PHY-TXSTART.confirm primitive from the PHY layer may mean that non-AP STA 1 (320) intends to start transmitting a frame. The above<LCM 전환> Condition 1) means that non-AP STA 1 (320) does not detect a frame, and conditions 2), 3), and 4) mean that non-AP STA 1 (320) does not perform frame transmission or that non-AP STA 1 (320) does not attempt to transmit additional frames. Condition 5) means that if non-AP STA 1 (320) is already transmitting a frame, switching the operation mode to LCM is prohibited. Meanwhile, the above-mentioned<LCM 전환> Condition 1) of the conditions may be used, but at least one of conditions 2) to 5) may not be used.

[0095] The aforementioned<LCM 전환> The two sub-conditions of condition 2) “the MAC layer does not send the PHY-TXSTART.request primitive to the PHY layer” and “the MAC layer does not receive the PHY-TXSTART.confirm primitive from the PHY layer” may be as follows. The above two sub-conditions can be combined according to various logical rules (e.g., logical OR, logical AND, etc.). For example, the two sub-conditions may be combined in a logical OR relationship. As a specific example, condition 2) may still be satisfied even if the MAC layer of non-AP STA 1 (320) has generated the PHY-TXSTART.request primitive, but the PHY layer of non-AP STA 1 (320) has not generated the PHY-TXSTART.confirm primitive. If the MAC layer of non-AP STA 1 (320) generates the PHY-TXSTART.request primitive and the PHY layer of non-AP STA 1 (320) generates the PHY-TXSTART.confirm primitive, condition 2) is not satisfied. Alternatively, the two sub-conditions may be combined in a logical AND relationship. As a specific example, if the MAC layer of non-AP STA 1 (320) generates the PHY-TXSTART.request primitive, condition 2) is not immediately satisfied, and likewise, if the PHY layer of non-AP STA 1 (320) generates the PHY-TXSTART.confirm primitive, condition 2) is not immediately satisfied. non-AP STA 1 (320) receives the PHY-RXSTART.indication primitive within the Tw time<LCM 전환> Even if the conditions are not met<LCM 전환 - 수신> If the conditions are met, it can operate as an LCM instead of an HCM.or,<LCM 전환> Without satisfying the conditions<LCM 전환 - 수신> If the conditions are not met, non-AP STA 1 (320) must operate as HCM without switching to LCM.

[0096]

[0097] <LCM 전환 - 수신>

[0098] - When the MAC layer of STA 1 receives the PHY-RXSTART.indication primitive from the PHY layer, but the recipient of the received frame is not STA 1

[0099] - If the MAC layer of STA 1 receives the PHY-RXSTART.indication primitive from the PHY layer and the received frame is a trigger frame, and the received trigger frame does not allocate a resource unit (RU) for STA 1

[0100] - If the MAC layer of STA 1 receives a PHY-RXSTART.indication primitive from the PHY layer and the received frame is a CTS (clear to send) frame, and the receiver address (RA) of the CTS frame is not the address of the AP to which STA 1 is connected (i.e., the address of AP 1)

[0101]

[0102] The above<LCM 전환> and<LCM 전환 - 수신> The PPDU defined in the conditions may be a PHY layer frame (physical layer frame). Here, the physical layer frame may include an MPDU (MAC protocol data unit), which is a MAC layer frame.

[0103] In the following, a method for performing a reverse transmission method during the DPS operation of a non-AP STA in a wireless LAN network is described based on the DPS operation method described in FIG. 3 above. The details described above may be applied identically to FIGS. 4 to 14 below, or they may be applied differently depending on each figure. Furthermore, while FIGS. 4 to 14 below describe the operation method of a non-AP STA performing a DPS operation, it may also be applied to cases where the non-AP STA does not perform a DPS operation (or is not limited to a DPS operation). In the above-described case, even in the case where the non-AP STA does not perform a DPS operation, the non-AP STA operating as HCM can be understood as operating in an "operation mode in which power saving operation cannot (or is not performed)." Additionally, the non-AP STA operating as LCM can be understood as operating in a "mode in which power saving operation is performed."

[0104] FIG. 4 is a diagram illustrating a dynamic low-power operation method during reverse transmission in a wireless LAN network to which the present disclosure applies.

[0105] Referring to FIG. 4, a case can be considered in which AP 1 (310) and non-AP STA 1 (320) operate in the same manner as in FIG. 3. Here, non-AP STA 1 (320) can perform DPS operations. After AP 1 (310) transmits a downlink frame to non-AP STA 1 (320), it may want to receive an uplink frame from non-AP STA 1 (320) by granting a reverse direction transmission opportunity to non-AP STA 1 (320) within the remaining TXOP (transmit opportunity) of AP 1 (310). AP 1 (310) can transmit an ICF (401) and receive an ICR (402) to transmit a downlink frame to non-AP STA 1 (320) as in FIG. 3. Here, non-AP STA 1 (320) can operate as an HCM with an ICF (401) and ICR (402) exchange procedure. A reverse direction grant (RDG) bit may be present in the MAC header of a downlink frame (403) transmitted by AP 1 (310) to non-AP STA 1 (320). When non-AP STA 1 (320) receives a downlink frame (403) transmitted by AP 1 (310) to non-AP STA 1 (320), non-AP STA 1 (320) can recognize that the RDG bit is set to 1. Thus, non-AP STA 1 (320) can recognize that an uplink frame is available for transmission within the TXOP of AP 1 (310). That is, non-AP STA 1 (320) may start transmitting frames within the interval allocated by the AP and must end transmitting frames within the allocated interval. Transmitting frames beyond the allocated interval by non-AP STA 1 (320) may not be allowed. Additionally, starting to transmit frames in a time interval outside the allocated interval by non-AP STA 1 (320) may not be allowed.As described above, non-AP STA 1 (320) can initiate a procedure to transmit a frame within an allocated interval (e.g., the MAC layer generates the PHY-TXSTART.request primitive, and the PHY layer generates the PHY-TXSTART.confirm primitive). That is, non-AP STA 1 (320) can perform a procedure to transmit a frame within an allocated interval, and the frame transmitted by non-AP STA 1 (320) can be terminated within the allocated interval. Therefore, non-AP STA 1 (320) is as described above<LCM 전환> It may be possible to maintain the HCM operation mode based on the interval allocated by the condition. That is, non-AP STA 1 (320) may maintain the operation mode when it needs to transmit an uplink frame rather than an immediate response frame even if it receives an ICF from AP 1 (310).

[0106] As a specific example, if the downlink frame (404) transmitted by AP 1 (310) is a frame that requests an immediate response frame, non-AP STA 1 (320) transmits a response frame, and the above-mentioned<Tw 조건 1> The Tw time can be initiated accordingly. The non-AP STA 1 (320) can transmit an uplink frame (404) to the AP 1 (310) within the Tw time. That is, the PHY-TXSTART.request primitive and the PHY-TXSTART.confirm primitive can be exchanged at the MAC layer and PHY layer of the non-AP STA 1 (320). Therefore, at the non-AP STA 1 (320),<LCM 전환> The condition may not be satisfied within the Tw time, and non-AP STA 1 (320) may continue to operate in HCM. While operating in HCM, non-AP STA 1 (320) may transmit an uplink frame (404) to AP 1 (310). For example, the uplink frame (404) may be a frame in which the More PPDU bit is set to 0. Here, non-AP STA 1 (320) may maintain the HCM operating mode or switch the operating mode back to LCM depending on the transition operation after uplink transmission. Specifically, during the transition operation after uplink transmission, non-AP STA 1 (320) may start Tw again after transmitting the uplink frame (404). If the uplink frame (404) transmitted by non-AP STA 1 (320) to AP 1 (310) is a frame that requests an immediate acknowledgment frame, non-AP STA 1 (320)<Tw 조건 3> Tw can be started after receiving a response frame for an uplink frame from AP 1 (310) according to AP 1 (310).On the other hand, if the uplink frame (404) transmitted by non-AP STA 1 (320) to AP 1 (310) is a frame that does not require an immediate acknowledgment frame, non-AP STA 1 (320)<Tw 조건 2> Depending on the time, Tw can be started from the time the transmission of the uplink frame transmitted by non-AP STA 1 (320) is completed. During the time of Tw<LCM 전환> If the condition is met, non-AP STA 1 (320) can switch the operation mode from HCM back to LCM.

[0107] Additionally, non-AP STA 1 (320) is a PHY-RXSTART.indication that occurs in the MAC layer during the Tw time.<LCM 전환 조건> This was not satisfied, but<LCM 전환 - 수신> If the conditions are satisfied, it can operate from HCM back to LCM. In cases other than those described above, non-AP STA 1 (320) may continue to operate as HCM without switching to LCM. non-AP STA 1 (320) is the above-described<Tw 조건 1> ,<Tw 조건 2> and<Tw 조건 3> If at least one of these occurs, Tw can be restarted. As described above during the Tw time.<LCM 전환> If the condition is met, non-AP STA 1 (320) can operate from HCM back to LCM. non-AP STA 1 (320) is formed when PHY-RXSTART.indication occurs in the MAC layer during Tw time.<LCM 전환> Even if the conditions are not met<LCM 전환 - 수신> When the condition is satisfied, it can operate from HCM back to LCM. As described above, non-AP STA 1 (320) can maintain the HCM operation mode without switching the operation mode to LCM during the time interval of transmitting the uplink frame (404).

[0108] FIG. 5 is a diagram illustrating a dynamic low-power operation method during reverse transmission in a wireless LAN network to which the present disclosure applies.

[0109] Referring to FIG. 5, a case can be considered in which AP 1 (310) and non-AP STA 1 (320) operate in the same manner as in FIG. 3. Here, non-AP STA 1 (320) can perform DPS operations. After AP 1 (310) transmits a downlink frame to non-AP STA 1 (320), it can share a portion of the TXOP (transmit opportunity) (i.e., time resources) with non-AP STA 1 (320) within the remaining TXOP (transmit opportunity) of AP 1 (310). As described above, non-AP STA 1 (320) can transmit an uplink frame to AP 1 (310) or perform peer-to-peer (P2P) transmission.

[0110] AP 1 (310) can transmit an ICF (401) and receive an ICR (402) to transmit a downlink frame (e.g., a TXS frame) to non-AP STA 1 (320) as shown in FIG. 3. non-AP STA 1 (320) can operate as an HCM through the exchange procedure of the ICF (401) and ICR (402). After that, AP 1 (310) can transmit a MU-RTS TXS (TXOP sharing) trigger frame, which is a frame that shares a TXOP, to non-AP STA 1 (320). The MU-RTS TXS trigger frame may be referred to as a TXS frame, but is not limited thereto. The TXS frame may indicate that non-AP STA 1 (320) can use a portion of AP 1 (310)'s TXOP. That is, the TXS frame can indicate a time interval (TXS interval) during which the non-AP STA 1 (320) can perform communication operations within the TXOP of AP 1 (310). When the non-AP STA 1 (320) receives a TXS frame transmitted by AP 1 (310) to the non-AP STA 1 (320), the non-AP STA 1 (320) can identify a TXS interval during which it can transmit the uplink frame and P2P frame of the non-AP STA 1 (320) within the TXOP of AP 1 (310).

[0111] As another example, instead of AP 1 (310) transmitting a separate TXS frame, ICF (401) can perform the function of the TXS frame. In the above case, when non-AP STA 1 (320) receives ICF (401), it not only switches the operating mode from LCM to HCM, but non-AP STA 1 (320) can also identify a TXS section within AP 1 (310)'s TXOP where non-AP STA 1 (320)'s uplink frame and P2P frame can be transmitted.

[0112] non-AP STA 1 (320) can transmit an uplink frame (405) or a P2P frame to AP 1 (310) within the TXS interval. non-AP STA 1 (320) can perform subsequent frame transmission based on the transition operation after uplink transmission described in FIG. 4. As another example, non-AP STA 1 (320) can perform subsequent frame transmission based on the transition operation after P2P transmission. That is, non-AP STA 1 (320) can initiate frame transmission within the TXS interval and must terminate frame transmission within the TXS interval. Frame transmission exceeding the TXS interval may not be allowed in non-AP STA 1 (320). Additionally, frame transmission initiation in a time interval outside the TXS interval may not be allowed in non-AP STA 1 (320). As described above, non-AP STA 1 (320) can initiate a procedure to transmit a frame within the TXS interval (e.g., the MAC layer generates the PHY-TXSTART.request primitive, and the PHY layer generates the PHY-TXSTART.confirm primitive). That is, non-AP STA 1 (320) can perform a procedure to transmit a frame within the TXS interval, and the frame transmitted by non-AP STA 1 (320) can be terminated within the TXS interval. Therefore, non-AP STA 1 (320) [is as described above]<LCM 전환> It may be possible to maintain the HCM operation mode based on the TXS interval under certain conditions. That is, even if non-AP STA 1 (320) receives an ICF from AP 1 (310), it may maintain the operation mode when it needs to transmit an uplink frame or a P2P frame (direct communication frame) instead of an immediate response frame.

[0113] Specifically, in the transition operation after P2P transmission, non-AP STA 1 (320) may need to restart Tw after transmitting the P2P frame. If the P2P frame transmitted by non-AP STA 1 (320) to non-AP STA 2 (530) is a frame that requires an immediate acknowledgment frame, non-AP STA 1 (320)<Tw 조건 3> Depending on this, Tw can be started after receiving a response frame for the P2P frame from non-AP STA 2 (530). On the other hand, if the P2P frame transmitted by non-AP STA 1 (320) to non-AP STA 2 (530) is a frame that does not require an immediate response frame, non-AP STA 1 (320)<Tw 조건 2> Depending on the time, non-AP STA 1 (320) can start Tw from the time the transmission of the frame it transmitted is completed. During the Tw time, non-AP STA 1 (320)<LCM 전환> If the condition is met, the operation mode can be switched back from HCM to LCM. Alternatively, non-AP STA 1 (320) can be switched back to LCM when PHY-RXSTART.indication occurs in the MAC layer during the Tw time.<LCM 전환 조건> Even if this is not satisfied<LCM 전환 - 수신> When the conditions are met, the operation mode can be switched back from HCM to LCM. Except for the cases described above, non-AP STA 1 (320) can continue to operate as HCM without switching to LCM.

[0114] non-AP STA 1 (320) is the above-mentioned<Tw 조건 1> ,<Tw 조건 2> and<Tw 조건 3> If at least one of these occurs, Tw can be restarted. As described above during the Tw time.<LCM 전환> If the condition is met, non-AP STA 1 (320) can operate from HCM back to LCM. non-AP STA 1 (320) is formed when PHY-RXSTART.indication occurs in the MAC layer during Tw time.<LCM 전환> Even if the conditions are not met<LCM 전환 - 수신> When the condition is satisfied, it can operate from HCM back to LCM. As described above, non-AP STA 1 (320) can operate by maintaining the HCM mode without switching the operation mode to LCM during the time interval of transmitting uplink frames or P2P frames. That is, non-AP STA 1 (320) can maintain the HCM mode during the TXS interval.

[0115] As another example, non-AP STA 1 (320) can perform the operation of returning a TXOP to the AP within the TXS interval. That is, non-AP STA 1 (320) can readjust (e.g. shorten) the TXS interval. The HT control field of the MAC header of the quality of service (QoS) frame transmitted by non-AP STA 1 (320) within the TXS interval may contain A-control information. The A-control information may contain an RDG / more PPDU subfield. If the value of the subfield is 0, non-AP STA 1 (320) can return the TXS interval to AP 1 (310). The time when non-AP STA 1 (320) transmits the aforementioned frame, or the time when non-AP STA 1 (320) transmits the aforementioned frame and receives an immediate response frame from AP 1 (310), may be the time of return of the aforementioned TXS interval. If non-AP STA 1 (320) explicitly returns the TXS interval to AP 1 (310), non-AP STA 1 (320) may immediately begin switching the operation mode to LCM at the time of return of the TXS interval. Alternatively, non-AP STA 1 (320) during the Tw time<LCM 전환> If the conditions are met, it can operate back from HCM to LCM. Alternatively, non-AP STA 1 (320) is formed when PHY-RXSTART.indication occurs in the MAC layer during the Tw time.<LCM 전환> Even if the conditions are not met<LCM 전환 - 수신> If the conditions are met, the operation mode can be switched back from HCM to LCM.

[0116] As another example, non-AP STA 1 (320) may use a method different from the method of maintaining the operating mode as HCM using the waiting time described above. During the TXS interval checked by non-AP STA 1 (320), the operating mode may not be switched to LCM separately, and when the TXS interval ends (e.g., end of TXS time interval, return of TXS time interval), the operating mode may be switched to LCM, but is not limited to such an embodiment.

[0117] FIG. 6 is a diagram illustrating a dynamic low-power operation method during reverse transmission in a wireless LAN network to which the present disclosure applies.

[0118] Referring to FIG. 6, a case can be considered in which AP 1 (310) and non-AP STA 1 (320) operate in the same manner as in FIG. 3. Here, non-AP STA 1 (320) can perform DPS operations. AP 1 (310) can receive an uplink frame from non-AP STA 1 (320) by sending a trigger frame to non-AP STA 1 (320) (i.e., by allocating uplink resources to non-AP STA 1 (320) through the sending of a trigger frame).

[0119] AP 1 (310) can transmit an ICF (401) and receive an ICR (402) to transmit a downlink frame (e.g., a trigger frame) to non-AP STA 1 (320) as shown in FIG. 3. non-AP STA 1 (320) can operate as an HCM through the exchange procedure of the ICF (401) and ICR (402). After that, AP 1 (310) can transmit a trigger frame (e.g., a basic trigger frame) (406), which is a frame that allocates uplink resources to non-AP STA 1 (320). The trigger frame (406) can indicate frequency information (e.g., resource unit information) and uplink time length information that non-AP STA 1 (320) can perform uplink transmission. When non-AP STA 1 (320) receives a trigger frame (406) transmitted by AP 1 (310) to non-AP STA 1 (320), non-AP STA 1 (320) can identify the uplink resources allocated by AP 1 (310) to non-AP STA 1 (320). Alternatively, instead of AP 1 (310) transmitting a separate trigger frame, an ICF can perform the function of a trigger frame (i.e., a basic trigger frame). In the above case, when non-AP STA 1 (320) receives the ICF, it not only switches the operating mode from LCM to HCM but also identifies the uplink resources allocated by AP 1 (310).

[0120] The non-AP STA 1 (320) can transmit an uplink frame (407) after receiving a trigger frame (406). After transmitting the uplink frame (407), the non-AP STA 1 (320) can decide whether to return to the LCM or maintain the HCM, which may be the same as the transition operation after the uplink transmission of FIG. 4 described above.

[0121] FIG. 7 is a diagram illustrating a dynamic power saving method applied to the present disclosure.

[0122] Referring to FIG. 7, a wireless LAN network may be configured. However, this is for convenience of explanation only and may not limit the scope of application of the present disclosure. A wireless LAN terminal that performs wireless LAN communication may operate in the wireless LAN network. Although the present disclosure describes based on an AP, non-AP STA 1, and non-AP STA 2, this is for convenience of explanation only and may not be limited thereto.

[0123] An AP can configure a basic service set (BSS). A BSS may be a transmission range or communication area in which an AP connects with at least one non-AP STA to perform communication. An AP may select a primary channel to use for channel access within the BSS, and may indicate the primary channel in a frame transmitted by the AP (e.g., beacon frame, probe response frame, etc.). At least one non-AP STA may establish a connection with the AP and access the channel using the primary channel indicated in the frame transmitted by the AP.

[0124] A wireless LAN terminal may have various operating bandwidths. For example, a wireless LAN terminal may have at least one of 320 MHz, 160 MHz, 80 MHz, 40 MHz, and 20 MHz, but is not limited thereto. Here, the operating bandwidths of STA 1 and STA 2 may be more limited than those of the AP. For example, the AP may have an operating bandwidth of 320 MHz, and STA 1 and STA 2 may have an operating bandwidth of 160 MHz. That is, STA 1 and STA 2 may be operating at half the operating bandwidth of the AP, but this is for convenience of explanation only and is not limited thereto.

[0125] In addition, wireless LAN terminals can perform EDCA (enhanced distributed channel access) operations. For example, for the convenience of explanation, the following description is based on the EDCA operation of a wireless LAN terminal, but it may not be limited to such terms or names.

[0126] A wireless LAN terminal (e.g., AP, non-AP STA 1, non-AP STA 2) can perform an enhanced distributed channel access (EDCA) operation. The EDCA operation may include at least one of a clear channel assessment (CCA) operation and an EDCA backoff procedure (hereinafter referred to as the backoff procedure). Specifically, the wireless LAN terminal (e.g., AP, non-AP STA 1, non-AP STA 2) can perform a CCA operation (hereinafter referred to as CCA) on a primary 20 MHz channel. CCA may be an operation to determine whether the channel is idle or busy. As a detailed operation of CCA, physical channel sensing (CS) may be an operation to detect carriers transmitted on the channel. Additionally, virtual CS may be an operation to verify the network allocation vector (NAV) established through a successful frame exchange. A wireless LAN terminal can perform CCA for a predetermined length of IFS (inter-frame space) (e.g., AIFS (arbitration IFS)[AC], etc.) depending on the type of frame to be transmitted (e.g., a frame with access category (AC) of VO, VI, BE, BO).

[0127] A wireless LAN terminal (e.g., AP, non-AP STA 1, non-AP STA 2) may initiate an EDCA backoff procedure (hereinafter referred to as the backoff procedure). The backoff procedure may be a procedure performed to reduce the probability of collision between wireless LAN terminals. The backoff procedure may be a procedure performed by an EDCAF (EDCA function) corresponding to the type of frame to be transmitted (e.g., AC) within the wireless LAN terminal. The EDCAF of the wireless LAN terminal may initiate the backoff procedure when traffic to be transmitted occurs (e.g., when data is entered into the transmit queue of the AC corresponding to the EDCAF) and the channel is occupied. As another example, the EDCAF of the wireless LAN terminal may initiate the backoff procedure if there is a separate instruction (e.g., when it receives an indicator instructing to start the backoff procedure via frame exchange).

[0128] The EDCAF of the wireless LAN terminal initiating the backoff procedure may randomly select a backoff counter (BC) within [0, CW (Contention Window)[AC]] determined by the associated AC. The BC value selected by the EDCAF associated with each AC may be the number of slots for which the EDCAF must perform CCA. If the channel is occupied as a result of the CCA operation performed by the EDCAF on a slot-by-slot basis, the EDCAF may perform a BC reduction operation in each slot. The slot length of the wireless LAN terminal used in the above-described operation may vary. For example, the slot length may consist of one or more AIFS[AC] times, EIFS[AC] times (EIFS - DIFS - AIFSN[AC] Х aSlotTime + aSIFSTime - aRxTxTurnaroundTime) times, or aSlotTime (e.g., 9us), but is not limited thereto. EDCAF can perform CCA according to the backoff procedure in slots corresponding to the selected BC value, and if the channel resulting from the CCA performed in one slot is idle, it can decrease BC by 1. If the channel resulting from the CCA performed when BC becomes 0 is idle, EDCAF can occupy the channel and perform frame transmission. For example, if the channel resulting from the CCA according to the backoff procedure is in an occupied state, the wireless LAN terminal can maintain its BC at the current value for use in the next backoff procedure. When the channel transitions from an occupied state to an idle state, the wireless LAN terminal (or the wireless LAN terminal's EDCAF) can perform the BC decrease procedure according to the EDCAF operation again.

[0129] The frame transmission procedure through EDCA operation may be a procedure in which a CCA is performed for AIFS[AC] on a primary 20 MHz channel, then a frame is transmitted at the slot boundary where BC becomes 0 after waiting for an additional slot time. The value indicated by AIFS[AC] may be the number of slots for performing CCA. Specifically, AIFS[AC] may be a time length of 'aSIFS(Short Inter-Frame Space)Time + AIFSN[AC](number specified per AC)* aSlotTime'.

[0130] EDCAF may want to access a wider bandwidth channel (broadband channel) including a main 20 MHz channel. To access the broadband channel, EDCAF performs CCA during AIFS[AC] on the main 20 MHz channel, and if the backoff counter is 0 at the AIFS[AC] slot boundary, it may transmit a frame including the broadband channel where the result of the CCA operation performed for PIFS (priority interframe space) time prior to the slot boundary is idle. Alternatively, if the backoff counter is not 0 at the AIFS[AC] slot boundary, it may wait for an additional slot time during which BC becomes 0 (i.e., the time during which at least one additional slot boundary occurs that allows BC to reach 0), and then transmit a frame including the broadband channel where the result of the CCA operation performed for PIFS (priority interframe space) time prior to the slot boundary where BS is 0 is idle. Alternatively, EDCAF may want to transmit frames using only the main 20 MHz channel regardless of the CCA result of the broadband channel. In the above case, EDCAF may transmit frames using only the main 20 MHz channel.

[0131] For example, the EDCA operation performed by an EDCAF within a wireless LAN terminal may be an EDCA operation performed by a wireless LAN terminal (e.g., AP, non-AP STA 1, non-AP STA 2). The EDCAF may be a logical entity that performs the aforementioned operation within the wireless LAN terminal, and the EDCA operation may be interpreted as an operation of the wireless LAN terminal. However, it is not limited thereto.

[0132] In the aforementioned EDCA operation, the main 20 MHz channel may be a channel configured by the AP during the BSS configuration process. That is, it may be a channel indicated in a frame transmitted by the AP (e.g., beacon frame, probe response frame, etc.). If the EDCAF within the wireless LAN terminal succeeds in accessing the channel as a result of performing an EDCA operation on the main 20 MHz channel, the EDCAF may transmit a frame of the corresponding access category (AC) using the successfully accessed channel (or bandwidth). The EDCAF within the wireless LAN terminal that transmitted the aforementioned frame may acquire a transmit opportunity (TXOP). The TXOP acquired by the EDCAF within the wireless LAN terminal may be a TXOP acquired by the wireless LAN terminal to which the EDCAF belongs, but is not limited thereto. The duration of the TXOP may be set to the time length from the time when the transmission of the first frame transmitted by the wireless LAN terminal (or the EDCAF of the corresponding AC within the wireless LAN terminal) is completed until the time indicated by the duration / ID field of the MAC header within the frame. That is, the wireless LAN terminal that transmitted the aforementioned first frame (or the EDCAF of the corresponding AC within the wireless LAN terminal) can perform transmit and receive operations from the time the first frame transmission is completed until the time indicated by the duration / ID field of the MAC header within the first frame.

[0133] Next, the wireless LAN terminal can perform a dynamic power save (DPS) operation. The following description is based on the DPS operation of the wireless LAN terminal, but it may not be limited to these terms or names.

[0134] A wireless LAN terminal (e.g., AP, non-AP STA) within a wireless LAN network may be a wireless LAN terminal capable of dynamically switching its operational capabilities (e.g., number of spatial streams, operational bandwidth or channels, modulation and coding scheme (MCS)), etc., between a lower capability mode (LCM) and a higher capability mode (HCM). That is, AP 1 (310) and non-AP STA 1 may be a DPS (dynamic power save) supported terminal (or, DPS STA). LCM may be an operational mode in which the wireless LAN terminal performs or waits to transmit or receive using an operational capability smaller than at least one of its maximum operational capabilities (e.g., operational bandwidth of 320 MHz or more, all available spatial streams, highest MCS value, etc.). For example, a DPS STA (e.g., AP 1, non-AP STA 1) operating in LCM may only use a bandwidth (e.g., primary 20 MHz channel) narrower than its maximum operational bandwidth of 320 MHz. As another example, a DPS STA operating in LCM (e.g., AP 1, non-AP STA 1) may use only one number of spatial streams (NSS). As another example, a DPS STA operating in LCM (e.g., AP 1, non-AP STA 1) may perform or wait for transmit and receive operations using the lowest modulation and coding scheme (MCS). Additionally, a DPS STA operating in LCM (e.g., AP 1, non-AP STA 1) may operate based on the combination described above. That is, a DPS STA operating in LCM (e.g., AP 1, non-AP STA 1) may operate using a capability smaller than the operating capability of the wireless LAN terminal in LCM.

[0135] HCM may be an operating mode in which a wireless LAN terminal performs or waits for transmission and reception using its maximum operating capability. In other words, it is an operating mode in which the wireless LAN terminal uses the maximum operating capability available when not using DPS operation. For example, a DPS STA (e.g., AP 1, non-AP STA 1) operating in HCM may operate at its maximum operating bandwidth of 320 MHz, use the maximum number of spatial streams (NSS) available, and perform or wait for transmission and reception using the highest modulation and coding scheme (MCS).

[0136] A single DPS STA can negotiate the use of DPS operations with other DPS STAs. For example, a non-AP STA and an AP within a BSS can recognize each other as DPS STAs through capability information exchanged during the (re)association process. A non-AP STA may wish to negotiate the use of DPS operations with an AP. For example, a non-AP STA may send an Ultra High Reliability Operating Mode Notification (UHR OMN) frame to an AP. The UHR OMN frame may contain information necessary for DPS operations. For example, a non-AP STA may instruct the use of DPS operations by setting the value of the DPS mode subfield within the UHR control field to 1. Additionally, the UHR OMN frame may include a DPS operation parameter field. The DPS operation parameter field may contain DPS operation information of the DPS STA sending the UHR OMN frame. Here, the DPS operation information of the DPS STA may include time information required for the DPS STA to switch operation modes. For example, it may include a DPS padding delay, which is the time required to switch from LCM to HCM, and a DPS transition delay, which is the time required to switch from HCM to LCM. The values ​​of the DPS padding delay and DPS transition delay may vary depending on the performance of the DPS STA and the operational capability to be switched.

[0137] An AP that receives a UHR OMN transmitted by a non-AP STA can acknowledge receipt via an acknowledgment frame (e.g., a (block) Acknowledgement frame). After the AP has finished preparing to support the non-AP STA's DPS operation, it can send a UHR OMN frame to the non-AP STA as an acknowledgment to the UHR OMN initially transmitted by the non-AP STA. The non-AP STA can receive the UHR OMN frame transmitted by the AP and recognize that the AP has finished preparing to support the DPS operation. The non-AP STA can receive the UHR OMN and acknowledge receipt via an acknowledgment frame. The negotiation process for the use of the DPS operation through the exchange of UHR OMN frames described above can be used in the same way when negotiating the discontinuation of the DPS operation. However, when negotiating the discontinuation of the DPS operation, the value of the DPS mode subfield within the UHR OMN may be set to 0.

[0138] A non-AP STA that has negotiated the use of DPS operation may switch its operation mode to LCM after the negotiation. The timing of the switch to LCM can vary. For example, a non-AP STA may switch to LCM at the time when the last acknowledgment frame exchanged during the DPS operation negotiation is received or at a later time (e.g., after SIFS or PIFS times). As another example, a non-AP STA may switch to LCM after the DPS operation negotiation while a wireless LAN terminal other than the DPS STA is performing a transmission. As yet another example, a non-AP STA may switch to LCM after receiving a separate instruction from the AP after the DPS operation negotiation.

[0139] After the aforementioned DPS negotiation, the non-AP STA acting as a DPS STA can operate as an LCM. Here, if the non-AP STA receives an initial control frame (ICF) from the AP that negotiated the DPS, the non-AP STA can switch its operating mode from LCM to HCM. The ICF may include padding corresponding to the DPS padding delay time, which is the time required for the non-AP STA acting as a DPS STA to switch its operating mode from LCM to HCM. After receiving the ICF in LCM and completing the operating mode switch, the DPS STA can transmit an Initial Control Response (ICR) frame. The DPS padding delay time may mean 'DPS operating mode switching time + SIFS time'. Alternatively, the DPS padding delay time may mean only the DPS operating mode switching time. When an AP transmits with CS required set in the ICF, padding can be added to the ICF so that the DPS STA can complete the DPS operation mode transition when the padding transmission time ends. If CS required is set in the ICF, and the DPS padding delay time means 'DPS operation mode transition time + SIFS time', padding corresponding to the time obtained by subtracting the SIFS time from the DPS padding delay can be included in the ICF. Alternatively, if CS required is set in the ICF and the DPS padding delay time means only the DPS operation mode transition time, padding corresponding to the DPS padding delay can be included in the ICF. On the other hand, if CS required is not set in the ICF, and the DPS padding delay time means 'DPS operation mode transition time + SIFS time', padding corresponding to the DPS padding delay can be included in the ICF.If CS required is not set in the ICF, and the DPS padding delay time refers only to the DPS operation mode switching time, padding corresponding to the time obtained by adding the SIFS time to the DPS padding delay can be included in the ICF.

[0140] The period during which a non-AP STA operates in HCM may be until the end of the TXOP acquired by the AP transmitting an ICF, or prior to that. The non-AP STA may need to switch its operating mode from HCM to LCM after the AP's TXOP has ended.

[0141] The aforementioned mode switching operation (mode switching, mode switch back) may also be performed upon receiving a mode switching indicator. The mode switching indicator may be an indicator that directs a transition from LCM to HCM or from HCM to LCM. For example, an AP may recognize a non-AP STA operating in LCM mode and may include a mode switching indicator directing a transition from LCM to HCM within the ICF transmitted to the non-AP STA. Upon receiving the aforementioned indicator, the non-AP STA may switch its mode of operation from LCM to HCM.

[0142] In addition, whether a DPS STA can perform frame transmission and reception operations during the operation mode switching time may vary depending on the implementation of the DPS STA. For example, a DPS STA may be unable to perform frame transmission and reception operations during the operation mode switching time. That is, a DPS STA cannot perform frame transmission and reception during the time interval corresponding to at least one of the DPS padding delay and the DPS switching delay. Additionally, a DPS STA may not be able to perform operations for channel access (e.g., CCA (clear channel assessment), etc.) during the time interval corresponding to at least one of the DPS padding delay and the DPS switching delay. As another example, a DPS STA may be able to perform frame transmission and reception operations during the operation mode switching time, and is not limited to a specific form.

[0143] Alternatively, the AP may quickly switch the DPS STA to MCM (mediate capability mode), which allows it to transmit and receive frames using capabilities enhanced by LCM but lower than HCM. A non-AP STA acting as a DPS STA may operate in LCM after DPS negotiation. A non-AP STA may switch its operating mode from LCM to MCM upon receiving an ICF from the AP that negotiated DPS instructing it to switch to MCM. The ICF instructing the switch to MCM may include padding corresponding to the DPS MCM padding delay, which is the time required for the DPS STA to switch its operating mode from LCM to MCM. For example, the DPS MCM padding delay may be a time shorter than the DPS padding delay, corresponding to 0, the SIFS time, or the PIFS time. The DPS STA may transmit an ICR after receiving the ICF instructing the switch from LCM to MCM and completing the operating mode transition. The operating bandwidth of the MCM may be limited to a main 20 MHz channel, but the MCS, NSS, and other capabilities may use values ​​higher than those used in the LCM (e.g., an intermediate MCS value, one or more NSS). However, it is not limited thereto. The AP can recognize the MCS and NSS of the PPDU transmitted by the non-AP STA through the PPDU's preamble, and can recognize which of the MCM's capabilities the non-AP STA used for transmission. For example, the non-AP STA may optionally enable the capabilities used by the MCM, and this is not limited to a specific form.

[0144] When a non-AP STA operating in LCM transmits a frame to an AP, it may transmit the frame after switching from LCM to MCM or HCM. The AP can check the preamble of the frame transmitted by the non-AP STA and verify the MCS, NSS, and bandwidth used for PPDU transmission. Through this, the AP can recognize which DPS operating state the non-AP STA is in. Subsequently, the AP can transmit a receive acknowledgment frame using parameters corresponding to the communication physical parameters (e.g., MCS, NSS, bandwidth) used in the PPDU transmitted by the non-AP STA.

[0145] Additionally, the wireless LAN terminal can perform EMLSR (Enhanced Multi-Link Single Radio) operations. For the sake of convenience of explanation, the following description refers to the EMLSR operation of the wireless LAN terminal, but it is not limited to this name or term. When a non-AP STA (EMLSR STA) that supports EMLSR operations performs an EMLSR operation, the non-AP STA (EMLSR STA) can initially perform a listening operation and wait for the reception of an ICF (e.g., MU-RTS TXS trigger frame, BSRP frame, etc.). When the AP transmits an ICF to the EMLSR STA, the EMLSR STA can switch to a normal transmission / reception operation capable of performing data transmission and reception on the link where the ICF was received, and perform data transmission and reception with the AP. The EMLSR STA can respond with a CTS frame after the SIFS time has elapsed from the time the ICF reception is completed. Here, the EMLSR STA can wait for the reception of a frame following the CTS frame it transmitted for a certain period of time. The aforementioned fixed time may be referred to as Tw time, and is a time composed of 'aSIFSTime + aSlotTime + aRxPHYStartDelay'. Additionally, aRxPHYStartDelay of Tw time may be 20 μs. The application point of Tw time is the next after receiving the initial control frame.<Tw 조건 1> ,<Tw 조건 2> and<Tw 조건 3> It could be one of them.

[0146]

[0147] <Tw 조건 1>

[0148] If the PPDU transmitted by the above EMLSR STA is a response to the most recently received frame from the AP, the time starts at the time the transmission of the PPDU is completed. For example, the Tw time may start at the time the transmission of the CTS frame is completed in the case where the AP transmits an ICF to the EMLSR STA and the EMLSR STA responds to the AP with a CTS frame.

[0149]

[0150] <Tw 조건 2>

[0151] If the PPDU received from an AP or another STA contains a frame that does not require an immediate response, start at the time the reception of the PPDU is complete.

[0152]

[0153] <Tw 조건 3>

[0154] If the PPDU transmitted by the EMLSR STA contains a frame that does not require an immediate response, it starts at the time the transmission of the PPDU is completed.

[0155]

[0156] STA 1 may switch to a listening operation and operate without performing normal transmission and reception operations if Tw starts after the completion of reception of the initial control frame and the following <listening operation switching condition> is satisfied during the Tw time.

[0157]

[0158] <Listening Action Switching Condition>

[0159] 1) The MAC layer of the EMLSR STA does not receive the PHY-RXSTART.indication primitive from the PHY layer, 2) The MAC layer of the EMLSR STA does not send the PHY-TXSTART.request primitive to the PHY layer, and the MAC layer of the EMLSR STA does not receive the PHY-TXSTART.confirm primitive from the PHY layer, 3) There is no nonempty transmit queue in the EMLSR STA, and 4) The EMLSR STA does not intend to transmit a frame or schedule a transmission.

[0160]

[0161] STA 1 can switch to a listening operation and operate even if the <listening operation switching condition> is not satisfied, if the <listening operation switching - receiving> condition is satisfied.

[0162]

[0163] <Listening Action Switch - Receive>

[0164] - When the MAC layer of STA 1 receives the PHY-RXSTART.indication primitive from the PHY layer, but the recipient of the received frame is not STA 1

[0165] - If the MAC layer of STA 1 receives the PHY-RXSTART.indication primitive from the PHY layer and the received frame is a trigger frame, and the received trigger frame does not allocate a resource unit (RU) for STA 1

[0166] - If the MAC layer of STA 1 receives a PHY-RXSTART.indication primitive from the PHY layer and the received frame is a CTS (clear to send) frame, and the receiver address (RA) of the CTS frame is not the address of the AP to which STA 1 is connected (i.e., the address of AP 1)

[0167]

[0168] Here, in the condition of <listening operation transition condition>, the MAC layer of EMLSR STA receiving the PHY-RXSTART.indication primitive from the PHY layer may indicate that EMLSR STA has detected a frame being received. The MAC layer of STA 1 sending the PHY-TXSTART.request primitive to the PHY layer and the MAC layer of STA 1 receiving the PHY-TXSTART.confirm primitive from the PHY layer may indicate that STA 1 intends to start transmitting a frame.

[0169] The <listening operation switching condition> of the EMLSR STA described above can be used as a condition for the DPS STA to switch the operation mode from HCM to LCM. Alternatively, the DPS STA may also perform the DPS operation using the operation described above in FIG. 3.

[0170] In FIGS. 8 to 14 below, operations including the broadband channel access operations and DPS operations described in FIGS. 7 and FIG. 3 may be applied in the same way, but it may also be possible to perform different operations depending on each figure.

[0171] FIG. 8 is a diagram illustrating a TXS operation method of a wireless LAN terminal applicable to the present disclosure.

[0172] Referring to FIG. 8, a TXS (TXOP Sharing) operation can be performed in a wireless LAN network. The following description is based on the TXS operation of a wireless LAN terminal, but it may not be limited to such terms or names. TXS (TXOP Sharing) may be an operation in which an AP (510) shares a transmit opportunity (TXOP) assigned to it with other wireless LAN terminals within the BSS. Specifically, the AP (510) may acquire a TXOP in the primary 20 MHz channel based on an EDCA operation. Subsequently, the AP (510) may transmit a frame within the TXOP acquired by the AP (510). Here, the AP (510) may want to share its TXOP with non-AP STA 1 (520), which is a non-AP STA within the BSS. AP (510) may send a MU-RTS (multi-user request-to-send) TXS (TXOP Sharing) trigger frame (601) to non-AP STA 1 (520) within the initially acquired TXOP. The MU-RTS TXS trigger frame (601) sent by AP (510) may be a frame indicating that the TXOP of AP (510) is shared with non-AP STA 1 (520). Upon receiving the MU-RTS TXS trigger frame (601) sent by AP (510), non-AP STA 1 (520) may recognize that AP (510) is sharing the TXOP of AP (510) with non-AP STA 1 (520). non-AP STA 1 (520) receives a MU-RTS TXS trigger frame (601) and can send a CTS (clear-to-send) frame (602) to AP (510) after a short interframe space (SIFS) time. After sending the CTS frame (602), non-AP STA 1 (520) can send the CTS frame (602) and then send a frame (603) after a SIFS time.The TXOP shared by AP (510) with non-AP STA 1 (520) may be a TXOP that ends at or before the end time of the TXOP acquired by the original AP (510). That is, the length of the TXOP shared by AP (510) with non-AP STA 1 (520) may be the same as or shorter than the length of the TXOP acquired by the original AP (510).

[0173] Here, the TXS operation performed by the AP (510) may have various operation modes. For example, the TXS operation may have TXS mode 1. However, this is merely a name for convenience of explanation and is not limited thereto. When the AP (510) performs TXS mode 1, a wireless LAN terminal that has received a shared TXOP from the AP (510) can transmit frames only to the AP (510) within the shared TXOP. In TXS mode 1, the AP (510) receives a CTS frame in response to a MU-RTS TXS trigger frame from a non-AP STA 1 (520) and can check whether frame transmission is performed during the PIFS (priority interframe space) time. For example, if non-AP STA 1 (520) does not transmit a frame during the PIFS time, the AP (510) may determine that non-AP STA 1 (520) no longer has frames to transmit and may retrieve the TXOP shared with non-AP STA 1 (520). The operation of the AP (510) detecting frame transmission by non-AP STA 1 (520) during the PIFS time may be performed for each frame based on the time of completion of transmission or reception of frames exchanged within the TXOP shared by the AP (510) with non-AP STA 1 (520).

[0174] Additionally, TXS mode 2 may exist in the TXS operation. When the AP (510) uses TXS mode 2, a wireless LAN terminal that has received a shared TXOP from the AP (510) can transmit a frame to at least one of the AP (510) and other non-AP STAs in the BSS within the shared TXOP. The AP (510) may not perform the frame transmission detection operation of non-AP STA 1 (520) described above in TXS mode 1 in TXS mode 2. That is, the AP (510) may not retrieve the shared TXOP even if no frame exchange is performed for a PIFS time based on the time of completion of the last frame transmission or reception within the TXOP shared with non-AP STA 1 (520). According to the above-described TXS operation, the AP (510) that has shared a TXOP with a non-AP STA can continue frame transmission and reception operations within its own TXOP from the time the shared TXOP ends. Alternatively, the AP (510) can continue frame transmission and reception operations within its own TXOP from the time the shared TXOP is retrieved. In addition, the details described above in FIG. 8 can be applied in the same way in FIG. 9 to FIG. 14 below, and it may also be possible to perform different operations depending on each figure.

[0175] FIG. 9 is a diagram showing the TXS operation method of a wireless LAN dynamic power saving terminal applied to the present disclosure.

[0176] Referring to FIG. 9, the wireless LAN network may have an AP (510) and non-AP STAs, such as non-AP STA 1 (520) and non-AP STA 2 (530), but this is for convenience of explanation only and is not limited thereto. Non-AP STA 1 (520) and non-AP STA 2 (530) may be associated with the AP (510) and operate. Additionally, the AP (510), non-AP STA 1 (520), and non-AP STA 2 (530) may be wireless LAN terminals that operate based on the EDCA operation of the wireless LAN terminal described above. That is, the AP (510), non-AP STA 1 (520), and non-AP STA 2 (530) perform channel access based on the EDCA backoff operation and channel access operation described above, and the wireless LAN terminal that succeeds in channel access can acquire a TXOP and transmit a frame. For example, AP (510) and non-AP STA 1 (520) may be DPS STAs that are DPS-supported wireless LAN terminals capable of operating based on the DPS operation of the wireless LAN terminal described above. non-AP STA 1 (520) may have negotiated the use of the DPS operation with AP (510). non-AP STA 1 (520) may be operating as an initial LCM. AP (510) and non-AP STA 1 (520) may be wireless LAN terminals that operate based on the TXS operation of the wireless LAN terminal of FIG. 8 described above. That is, AP (510) may share a portion of the TXOP it has acquired with non-AP STA 1 (520), and non-AP STA 1 (520) may transmit frames to AP (510) or another non-AP STA (e.g., STA 2) within the shared TXOP according to the TXS mode.

[0177] AP (510) may have initially acquired a TXOP by transmitting a CTS-to-Self frame (604). The CTS-to-Self frame (604) transmitted by AP (510) may be a frame in which the receiver address (RA) in the MAC header is set to the MAC address (e.g., BSSID) of AP (510). After transmitting the CTS-to-Self frame (604), AP (510) may exchange frames with other non-AP STAs (e.g., STA 1, STA 2) within the BSS within its TXOP. Here, AP (510) may want to share a portion of its TXOP with other non-AP STAs (e.g., STA 1) within the BSS. For example, AP (510) may want to share a TXOP in at least one of the following cases: when there is no more data to transmit in its TXOP, when it recognizes that there is data to transmit to another non-AP STA in the BSS, when it recognizes that direct communication between other non-AP STAs in the BSS is necessary, or when another non-AP STA in the BSS requests AP (510) to share the TXOP, but is not limited thereto.

[0178] Here, a problem may occur when AP (510) shares a TXOP through a TXS operation with a non-AP STA operating as an LCM. Specifically, AP (510) may decide to share a portion of its TXOP with non-AP STA 1 (520). However, non-AP STA 1 (520) may be operating as an LCM. In the above situation, if AP (510) shares a TXOP by transmitting a MU-RTS TXS trigger frame (605) in duplicate across the entire bandwidth of the acquired TXOP to non-AP STA 1 (520) in 20 MHz increments, non-AP STA 1 (520) may need to use transmission parameters used in LCM. Accordingly, non-AP STA 1 (520) can transmit a response frame (e.g., CTS frame) (605) to a MU-RTS TXS trigger frame (605) using only the primary 20 MHz channel. When non-AP STA 1 (520) transmits a CTS frame (605) in response to a MU-RTS TXS trigger frame (605), the transmission bandwidth of subsequent frames exchanged within the shared TXOP interval may be limited to the bandwidth in which the CTS frame (605) was transmitted. Therefore, when AP (510) shares a TXOP with non-AP STA 1 (520) operating as an LCM, the operating bandwidth of the shared TXOP may be limited to the primary 20 MHz channel. In the following, the above is referred to as a TXS bandwidth limitation issue, but this is for convenience of explanation only and is not limited thereto.

[0179] Here, a method to resolve the aforementioned 'TXS bandwidth limiting problem' may be required. Specifically, the AP (510) may transmit a MU-RTS TXS trigger frame (605) to share a TXOP with a non-AP STA 1 (520). Here, the MU-RTS TXS trigger frame (605) may be a frame that is duplicated in a non-HT Duplicate PPDU format in 20 MHz units across the entire bandwidth of the TXOP acquired by the AP (510). The AP (510) may include information in the MU-RTS TXS trigger frame (605) regarding the entire bandwidth over which the MU-RTS TXS trigger frame (605) is transmitted. The information regarding the total bandwidth in which the MU-RTS TXS trigger frame (605) is transmitted, which is included in the MU-RTS TXS trigger frame (605), may be the bandwidth indicated by the UL (uplink) BW (bandwidth) field within the common info field in the MU-RTS TXS trigger frame (605). A non-AP STA 1 (520) operating as an LCM can receive the MU-RTS TXS trigger frame (605) on at least the main 20 MHz channel and can verify the bandwidth information (e.g., UL BW field) included in the MU-RTS TXS trigger frame (605). Through this, the non-AP STA 1 (520) can recognize the information regarding the total bandwidth in which the MU-RTS TXS trigger frame (605) is transmitted. The non-AP STA 1 (520) receives a MU-RTS TXS trigger frame (605) and can respond to the AP (510) with a CTS frame (606) after a short interframe space (SIFS) time. Since the CTS frame (606) is transmitted using the operating bandwidth used by the non-AP STA 1 (520) in the LCM, it can only be transmitted on the main 20 MHz channel.That is, when non-AP STA 1 (520) performs a DPS operation, it may transmit a CTS frame having a bandwidth different from the bandwidth information indicated by the AP (510) in the trigger frame. The aforementioned MU-RTS TXS frame may be an ICF, and the CTS frame may be an ICR. non-AP STA 1 (520) may transmit a CTS frame (606) containing an indicator that instructs to perform a mode switching operation from LCM to HCM in the DPS operation. The AP (510) receives the CTS frame (606) transmitted by non-AP STA 1 (520) and can verify the aforementioned indicator included in the CTS frame (606). Thus, the AP (510) can recognize that the operation mode of non-AP STA 1 (520) has switched from LCM to HCM after non-AP STA 1 (520) transmits the CTS frame (606).

[0180] If non-AP STA 1 (520) does not perform frame transmission for a certain period of time (e.g., PIFS time after the last frame transmission) within the TXOP shared from AP (510), the AP (510) that shared its TXOP with non-AP STA 1 (520) can reclaim the TXOP. Here, if non-AP STA 1 (520) operating in LCM switches its operating mode to HCM and the time taken to switch is longer than the PIFS time, a problem may occur when the shared TXOP is reclaimed according to the TXOP reclamation condition described above. Accordingly, when non-AP STA 1 (520) instructs to switch its operation mode, AP (510) receives the CTS frame (606) transmitted by non-AP STA 1 (520) and may not retrieve the TXOP for the time of non-AP STA 1 (520)'s DPS padding delay or non-AP STA 1 (520)'s 'DPS padding delay + PIFS (Priority Interframe Space)' time. That is, AP (510) may wait without retrieving the TXOP until the non-AP STA 1 (520) completes the operation mode switch.

[0181] As another example, AP (510) may share a TXOP with a non-AP STA 1 (520) operating in LCM even if there is no indicator within the CTS frame (606) instructing to perform a mode switching operation from LCM to HCM. In the above case, AP (510) may assume that non-AP STA 1 (520) will start transmitting and receiving frames after switching to HCM. Accordingly, AP (510) may not retrieve the TXOP for the time of the non-AP STA 1 (520)'s DPS padding delay or the non-AP STA 1 (520)'s 'DPS padding delay + PIFS' time after receiving the CTS frame (606) transmitted by non-AP STA 1 (520) in response to the MU-RTS TXS trigger frame (605) in which the TXOP is shared. That is, AP (510) can wait without retrieving TXOP until the operation mode switching of non-AP STA 1 (520) is complete.

[0182] After transmitting the CTS frame (606), the non-AP STA 1 (520) may have completed switching its operating mode from LCM to HCM and may transmit a frame (e.g., data frame) (607) according to the TXS mode within the shared TXOP. For example, if the AP (510) shares the TXOP in TXS mode 1, the non-AP STA 1 (520) may transmit the data frame (607) to the AP (510) after transmitting the CTS frame (606). For another example, if the AP (510) shares the TXOP in TXS mode 2, the non-AP STA 1 (520) may transmit the CTS frame (606) and transmit the data frame (607) to at least one of the AP (510) and another non-AP STA (e.g., STA 2) within the BSS. The frame transmitted by non-AP STA 1 (520) within the shared TXOP may be a frame transmitted using the bandwidth in which the MU-RTS TXS trigger frame (605) was transmitted, based on the bandwidth information included in the MU-RTS TXS trigger frame (605) transmitted by the AP (510) to share the TXOP. That is, even if non-AP STA 1 (520) transmitted the CTS frame (606) using only the main 20 MHz channel, it can subsequently transmit a frame in the shared TXOP using the entire bandwidth in which the MU-RTS TXS trigger frame (605) was transmitted (i.e., the entire bandwidth of the TXOP initially acquired by the AP (510)). non-AP STA 1 (520) can switch the operation mode to HCM after transmitting the CTS frame (606). A non-AP STA 1 (520) that has switched to HCM can transmit a data frame using the bandwidth supported by the HCM of the non-AP STA 1 (520) within the bandwidth shared by the AP (510), based on the bandwidth information of the MU-RTS TXS trigger frame (605) transmitted by the AP (510) to share the TXOP.After non-AP STA 1 (520) switches to HCM to transmit a data frame, it can sense the bandwidth supported by the HCM of non-AP STA 1 (520) for a certain period of time (e.g., SIFS or PIFS) to identify idle channels and transmit a data frame (607) using the idle channels. Alternatively, if it receives a shared TXOP set to CTS-to-Self, non-AP STA 1 (520) can transmit a frame using a bandwidth equal to or smaller than the bandwidth of CTS-to-Self. Thus, non-AP STA 1 (520) can transmit a data frame using the bandwidth supported by the HCM of non-AP STA 1 (520) within the bandwidth set to CTS-to-Self (i.e., the bandwidth indicated by the MU-RTS TXS trigger frame) without performing channel sensing for the aforementioned certain period of time.

[0183] non-AP STA 1 (520) can switch to LCM at the time of TXOP termination when the TXOP shared by AP (510) is terminated. As another example, when the TXOP shared by AP (510) is terminated, non-AP STA 1 (520) can wait for additional frame reception for a certain period of time (e.g., SIFS time) after the TXOP termination time, and then switch to LCM if no frame is received. As yet another example, even if the TXOP shared by AP (510) is terminated, non-AP STA 1 (520) can operate as HCM until the time of TXOP termination of the first TXOP acquired by AP (510), and then switch to LCM at the time of TXOP termination of the first TXOP acquired by AP (510).

[0184] In the DPS operation of the non-AP STA 1 (520) described above, the conditions described in FIG. 3 and FIG. 7 may be applied as conditions for switching from HCM to LCM. Specifically, the operation may be switched to LCM based on at least one of the conditions for starting Tw in FIG. 3 and the conditions for starting Tw of the 'EMLSR operation' in FIG. 7. The Tw, <switching>, and <switching-receiving> described below may satisfy at least one of the Tw in FIG. 3 and the Tw of the 'EMLSR operation' in FIG. 7, and may not be limited to a specific form.

[0185] For example, at the point when non-AP STA 1 (520) receives a BA frame for the first data frame after completing the transition from LCM to HCM and transmitting the first data frame, non-AP STA 1 (520)<Tw 조건 2> It may correspond to, and can wait without switching to LCM for Tw time. Afterwards, non-AP STA 1 (520) for Tw time<LCM 전환 조건> (or whether the <listening operation switching condition>) is satisfied can be checked. The non-AP STA 1 (520) may start the Tw time at the time when the reception of the BA frame for the first data frame ends. The non-AP STA 1 (520) may, for the Tw time from the time when the transmission of the BA frame for the first data frame ends<LCM 전환 조건> It can be confirmed that the state corresponds to (or <listening operation switching condition>). Therefore, non-AP STA 1 (520) can switch the operation mode from HCM to LCM after the Tw time that started at the time of ending reception of the BA frame for the first data frame.

[0186] FIG. 10 is a diagram showing the TXS operation method of a wireless LAN dynamic power saving terminal applied to the present disclosure.

[0187] Referring to FIG. 10, the wireless LAN network may have an AP (510) and non-AP STAs, such as non-AP STA 1 (520) and non-AP STA 2 (530), but this is for convenience of explanation only and is not limited thereto. The non-AP STA 1 (520) and non-AP STA 2 (530) may operate by being associated with the AP. Additionally, the AP (510), non-AP STA 1 (520), and non-AP STA 2 (530) may be wireless LAN terminals that operate based on the EDCA operation of the wireless LAN terminal described above. That is, the AP (510), non-AP STA 1 (520), and non-AP STA 2 (530) perform channel access based on the EDCA backoff operation and channel access operation described above, and the wireless LAN terminal that succeeds in channel access can acquire a TXOP and transmit a frame. For example, AP (510) and non-AP STA 1 (520) may be DPS STAs that are DPS-supported wireless LAN terminals capable of operating based on the DPS operation of the wireless LAN terminal described above. Here, non-AP STA 1 (520) may have negotiated the use of the DPS operation with AP (510). Thus, non-AP STA 1 (520) may be operating as an initial LCM. AP (510) and non-AP STA 1 (520) may be wireless LAN terminals that operate based on the TXS operation of the wireless LAN terminal of FIG. 8 described above. That is, AP (510) may share a portion of the TXOP it has acquired with non-AP STA 1 (520), and non-AP STA 1 (520) may transmit frames to AP (510) or another non-AP STA (e.g., STA 2) within the shared TXOP according to the TXS mode.

[0188] AP (510) may have initially acquired a TXOP by transmitting a CTS-to-Self frame (604). The CTS-to-Self frame (604) transmitted by AP (510) may be a frame in which the receiver address (RA) in the MAC header is set to the MAC address (e.g., BSSID) of AP (510). After transmitting the CTS-to-Self frame (604), AP (510) may exchange frames with other non-AP STAs (e.g., STA 1, STA 2) within the BSS within its TXOP. AP (510) may want to share a portion of its TXOP with other non-AP STAs (e.g., STA 1) within the BSS. For example, AP (510) may want to share a TXOP in at least one of the following cases: when there is no more data to transmit in its TXOP, when it recognizes that there is data to transmit to another non-AP STA in the BSS, when it recognizes that direct communication between other non-AP STAs in the BSS is necessary, or when another non-AP STA in the BSS requests AP (510) to share the TXOP, but is not limited thereto.

[0189] A method to solve the ‘TXS bandwidth limitation problem’ described above in FIG. 9 may be considered. Specifically, the AP (510) may transmit a MU-RTS TXS trigger frame (605) to share a TXOP with a non-AP STA 1 (520). Here, the MU-RTS TXS trigger frame (605) may be a frame that is duplicated in a non-HT Duplicate PPDU format in 20 MHz units across the entire bandwidth of the TXOP acquired by the AP (510). The AP (510) may include information in the MU-RTS TXS trigger frame (605) regarding the entire bandwidth over which the MU-RTS TXS trigger frame (605) is transmitted. The information regarding the total bandwidth in which the MU-RTS TXS trigger frame (605) is transmitted, which is included in the MU-RTS TXS trigger frame (605), may be the bandwidth indicated by the UL (uplink) BW (bandwidth) field within the common info field in the MU-RTS TXS trigger frame (605). A non-AP STA 1 (520) operating as an LCM can receive the MU-RTS TXS trigger frame (605) on at least the main 20 MHz channel and can verify the bandwidth information (e.g., UL BW field) included in the MU-RTS TXS trigger frame (605). Through this, the non-AP STA 1 (520) can recognize the information regarding the total bandwidth in which the MU-RTS TXS trigger frame (605) is transmitted. The non-AP STA 1 (520) receives a MU-RTS TXS trigger frame (605) and can respond to the AP (510) with a CTS frame (606) after a short interframe space (SIFS) time. Since the CTS frame (606) is transmitted using the operating bandwidth used by the non-AP STA 1 (520) in the LCM, it can only be transmitted on the main 20 MHz channel.That is, when non-AP STA 1 (520) performs a DPS operation, non-AP STA 1 (520) can transmit a CTS frame having a bandwidth different from the bandwidth information indicated by AP (510) (510) in the trigger frame. The above-mentioned MU-RTS TXS frame may be an ICF, and the CTS frame may be an ICR.

[0190] non-AP STA 1 (520) may be a DPS STA capable of transmitting frames while simultaneously performing an operation mode switch based on DPS operation. Here, non-AP STA 1 (520) may transmit a CTS frame (606) with padding added. The padding added to the CTS frame (606) may be set to a time length equal to the DPS padding delay of non-AP STA 1 (520). When non-AP STA 1 (520) transmits a CTS frame (606), non-AP STA 1 (520) may switch the operation mode of non-AP STA 1 (520) from LCM to HCM while transmitting the padding of the CTS frame (606). Accordingly, when the transmission of the CTS frame (606) is completed, the non-AP STA 1 (520) can operate as an HCM and transmit the CTS frame (606). After the SIFS (or PIFS) time, the MU-RTS TXS trigger frame (605) can be transmitted by checking the available bandwidth among the total bandwidth.

[0191] The non-AP STA 1 (520) can transmit a CTS frame (606) and complete the transition of its operation mode from LCM to HCM. Here, the non-AP STA 1 (520) can transmit a frame (e.g., a data frame) according to the TXS mode within the shared TXOP. For example, if the AP (510) shares the TXOP in TXS mode 1, the non-AP STA 1 (520) can transmit a CTS frame (606) and transmit a data frame (607) to the AP (510). For another example, if the AP (510) shares the TXOP in TXS mode 2, the non-AP STA 1 (520) can transmit a CTS frame (606) and transmit a data frame (607) to at least one of the AP (510) and another non-AP STA (e.g., STA 2) within the BSS. The frame (607) transmitted by non-AP STA 1 (520) within the shared TXOP may be a frame transmitted using the bandwidth in which the MU-RTS TXS trigger frame (605) was transmitted, based on the bandwidth information included in the MU-RTS TXS trigger frame (605) transmitted by the AP (510) to share the TXOP. That is, even if non-AP STA 1 (520) transmitted the CTS frame (606) using only the main 20 MHz channel, it can subsequently transmit a frame in the shared TXOP using the entire bandwidth in which the MU-RTS TXS trigger frame (605) was transmitted (i.e., the entire bandwidth of the TXOP initially acquired by the AP (510)). non-AP STA 1 (520) can switch the operation mode to HCM after transmitting the CTS frame (606).A non-AP STA 1 (520) that has switched to HCM can transmit a data frame (607) using the bandwidth supported by the HCM of non-AP STA 1 (520) within the bandwidth shared by the AP (510), based on the bandwidth information of the MU-RTS TXS trigger frame (605) transmitted by the AP (510) to share the TXOP. After switching to HCM to transmit the data frame (607), the non-AP STA 1 (520) can sense the bandwidth supported by the HCM of non-AP STA 1 (520) for a certain period of time (e.g., SIFS or PIFS) to identify idle channels and transmit the data frame (607) using the idle channels. Alternatively, if a TXOP configured as a CTS-to-Self frame is shared, non-AP STA 1 (520) may transmit a frame using a bandwidth equal to or smaller than the bandwidth of the CTS-to-Self frame (604). Thus, non-AP STA 1 (520) may transmit a data frame using a bandwidth supported by the HCM of non-AP STA 1 (520) within the bandwidth configured as a CTS-to-Self frame (i.e., the bandwidth indicated by the MU-RTS TXS trigger frame) without performing channel sensing for the aforementioned period of time.

[0192] non-AP STA 1 (520) can switch to LCM at the time of TXOP termination when the TXOP shared by AP (510) is terminated. As another example, when the TXOP shared by AP (510) is terminated, non-AP STA 1 (520) can wait for additional frame reception for a certain period of time (e.g., SIFS time) after the TXOP termination time, and then switch to LCM if no frame is received. As yet another example, even if the TXOP shared by AP (510) is terminated, non-AP STA 1 (520) can operate as HCM until the time of TXOP termination of the first TXOP acquired by AP (510), and then switch to LCM at the time of TXOP termination of the first TXOP acquired by AP (510).

[0193] In the DPS operation of the non-AP STA 1 (520) described above, the conditions described in FIG. 3 and FIG. 7 may be applied as conditions for switching from HCM to LCM. Specifically, the operation may be switched to LCM based on at least one of the conditions for starting Tw in FIG. 3 and the conditions for starting Tw of the 'EMLSR operation' in FIG. 7. The Tw, <switching>, and <switching-receiving> described below may satisfy at least one of the Tw in FIG. 3 and the Tw of the 'EMLSR operation' in FIG. 7, and may not be limited to a specific form.

[0194] With the condition that the non-AP STA 1 (520) starts the Tw time of FIG. 3 (or the Tw time of the 'EMLSR operation' of FIG. 7) at the time when the transition from LCM to HCM is completed after receiving a MU-RTS TXS trigger frame (605) from the AP (510) and responding with a CTS frame (606).<Tw 조건 1> This may correspond to. non-AP STA 1 (520) may wait without switching to LCM for Tw time. Afterwards, non-AP STA 1 (520) for Tw time<LCM 전환 조건> (or whether the <listening operation transition condition>) is satisfied can be checked. non-AP STA 1 (520) may have started the Tw time at the time the CTS frame transmission ended after the transition to HCM was completed, and non-AP STA 1 (520) during the aforementioned Tw time<LCM 전환 조건> It may have been confirmed that it is not in a state corresponding to (or <listening operation switching condition>). Therefore, non-AP STA 1 (520) can transmit the first data frame (608) from HCM without switching from HCM to LCM.

[0195] At the time when non-AP STA 1 (520) receives a BA frame for the first data frame (608) after transmitting the first data frame (608), non-AP STA 1 (520) starts the Tw time of FIG. 3 (or the Tw time of the 'EMLSR operation' of FIG. 7) as a condition<Tw 조건 2> It may correspond to, and can wait without switching to LCM for Tw time. Afterwards, non-AP STA 1 (520) for Tw time<LCM 전환 조건> (or whether the <listening operation switching condition>) is satisfied can be checked. The non-AP STA 1 (520) may start the Tw time at the time of end of reception of the BA frame for the first data frame (608). The non-AP STA 1 (520) may, during the aforementioned Tw time from the time of end of transmission of the BA frame for the first data frame (608).<LCM 전환 조건> It may be confirmed that the state does not correspond to (or <listening operation switching condition>). Therefore, non-AP STA 1 (520) can transmit the second data frame (609) from HCM without switching from HCM to LCM.

[0196] At the point when non-AP STA 1 (520) receives a BA frame from AP (510) after transmitting a second data frame (609), non-AP STA 1 (520) may wait without switching to LCM for the Tw time of FIG. 3 (or the Tw time of the 'EMLSR operation' of FIG. 7). Afterwards, non-AP STA 1 (520) during the Tw time<LCM 전환 조건> (or whether the <listening operation switching condition>) is satisfied can be checked. The non-AP STA 1 (520) may start the Tw time at the time of end of reception of the BA frame for the second data frame (609), and for the Tw time from the time of end of transmission of the BA frame for the second data frame (609).<LCM 전환 조건> It can be confirmed that the state corresponds to (or <listening operation switching condition>). Therefore, non-AP STA 1 (520) can switch the operation mode from HCM to LCM after the Tw time that started at the time of ending reception of the BA frame for the second data frame (609).

[0197] FIG. 11 is a diagram showing the TXS operation method of a wireless LAN dynamic power saving terminal applied to the present disclosure.

[0198] Referring to FIG. 11, the wireless LAN network may have an AP (510) and non-AP STAs, such as non-AP STA 1 (520) and non-AP STA 2 (530), but this is for convenience of explanation only and is not limited thereto. The non-AP STA 1 (520) and non-AP STA 2 (530) may operate by being associated with the AP (510). Additionally, the AP (510), non-AP STA 1 (520), and non-AP STA 2 (530) may be wireless LAN terminals that operate based on the EDCA operation of the wireless LAN terminal described above. That is, the AP (510), non-AP STA 1 (520), and non-AP STA 2 (530) perform channel access based on the EDCA backoff operation and channel access operation described above, and the wireless LAN terminal that succeeds in channel access can acquire a TXOP and transmit a frame. For example, the AP (510) and non-AP STA 1 (520) may be DPS STAs, which are DPS-supported wireless LAN terminals capable of operating based on the DPS operation of the wireless LAN terminal described above. Here, the non-AP STA 1 (520) may have negotiated the use of the DPS operation with the AP (510). Therefore, the non-AP STA 1 (520) may be operating as an initial LCM. The AP (510) and non-AP STA 1 (520) may be wireless LAN terminals that operate based on the TXS operation of the wireless LAN terminal of FIG. 8 described above. That is, AP (510) can share a portion of the TXOP it has acquired with non-AP STA 1 (520), and non-AP STA 1 (520) can transmit frames to AP (510) or another non-AP STA (e.g., STA 2) within the shared TXOP according to the TXS mode.

[0199] AP (510) may have initially acquired a TXOP by transmitting a CTS-to-Self frame (604). The CTS-to-Self frame (604) transmitted by AP (510) may be a frame in which the receiver address (RA) in the MAC header is set to the MAC address (e.g., BSSID) of AP (510). After transmitting the CTS-to-Self frame (604), AP (510) may exchange frames with other non-AP STAs (e.g., STA 1, STA 2) within the BSS within its TXOP. AP (510) may want to share a portion of its TXOP with other non-AP STAs (e.g., STA 1) within the BSS. For example, AP (510) may want to share a TXOP in at least one of the following cases: when there is no more data to transmit in its TXOP, when it recognizes that there is data to transmit to another non-AP STA in the BSS, when it recognizes that direct communication between other non-AP STAs in the BSS is necessary, or when another non-AP STA in the BSS requests AP (510) to share the TXOP, but is not limited thereto.

[0200] Here, a method may be required to resolve the 'TXS bandwidth limiting problem' described above in FIG. 9. Specifically, the AP (510) may transmit a MU-RTS TXS trigger frame (605) to share a TXOP with a non-AP STA 1 (520). Here, the MU-RTS TXS trigger frame (605) may be a frame that is duplicated in a non-HT Duplicate PPDU format in 20 MHz units across the entire bandwidth of the TXOP acquired by the AP (510). The AP (510) may include information in the MU-RTS TXS trigger frame (605) regarding the entire bandwidth over which the MU-RTS TXS trigger frame (605) is transmitted. The information regarding the total bandwidth in which the MU-RTS TXS trigger frame (605) is transmitted, which is included in the MU-RTS TXS trigger frame (605), may be the bandwidth indicated by the UL (uplink) BW (bandwidth) field in the common info field within the MU-RTS TXS trigger frame (605). A non-AP STA 1 (520) operating as an LCM can receive the MU-RTS TXS trigger frame (605) on at least the main 20 MHz channel and can check the bandwidth information (e.g., UL BW field) included in the MU-RTS TXS trigger frame (605).

[0201] Additionally, non-AP STA 1 (520) can recognize that it needs to switch its operation mode from LCM to HCM after checking the operation mode switching time indicator included in the aforementioned MU-RTS TXS trigger frame (605). Here, padding may be included in the MU-RTS TXS trigger frame (605) transmitted by the AP (510). The padding included in the MU-RTS TXS trigger frame (605) may be intended to guarantee the operation mode switching time of non-AP STA 1 (520), and the length of the time may vary. If padding is included in the MU-RTS TXS trigger frame (605), the frame may be composed of 'MU-RTS TXS trigger frame + intermediate FCS (Frame Control Sequence) + padding'. Intermediate FCS is a set of bits that can detect errors, and the STA can properly decode the MU-RTS TXS trigger frame by checking up to the Intermediate FCS. Here, padding can be decoded, and the operation mode transition can begin.

[0202] Since the MU-RTS TXS trigger frame (605) is a variant of the trigger frame, a CS Required bit can be set to instruct the CS operation according to the EDCA operation to be performed when transmitting a response frame for the MU-RTS TXS trigger frame (605). For example, the CS Required bit of the MU-RTS TXS trigger frame (605) can be set to 1. In the above case, when the non-AP STA 1 (520) transmits the CTS frame (606) as a response frame, it may perform the CS operation according to the above-described EDCA operation for a SIFS (or PIFS) time. The non-AP STA 1 (520) may transmit the CTS frame (606) within the available bandwidth according to the result of the CS operation. As another example, the CS Required bit of the MU-RTS TXS trigger frame (605) can be set to 0. In the above-described case, the non-AP STA 1 (520) may not perform a CS operation according to the EDCA operation when transmitting a CTS frame (606) as a response frame, and may transmit a CTS frame (606) within the bandwidth in which a MU-RTS TXS trigger frame (605) is received. When the AP (510) transmits with CS Required set to 1, it may transmit a frame including padding for a time corresponding to the operation mode transition time so that the terminal can perform CS for a SIFS time after switching the operation mode, and when it transmits with CS Required set to 0, it may include padding for a time corresponding to 'operation mode transition time + SIFS' time.

[0203] Here, when a non-AP STA 1 (520) operating as an LCM receives a MU-RTS TXS trigger frame (605) with the CS Required bit set to 1, the bandwidth of the CS operation performed by the non-AP STA 1 (520) according to the EDCA operation may be limited to the main 20 MHz channel. Taking the above into consideration, the AP (510) may transmit the MU-RTS TXS trigger frame (605) including padding. The padding may be set to a time length equal to or longer than the time length indicating the DPS padding delay of the non-AP STA 1 (520). As another example, the AP (510) may transmit the MU-RTS TXS trigger frame (605) including an Intermediate FCS before including padding. The Intermediate FCS may be in the form of a field or subfield containing all or part of the information of the Frame Check Sequence (FCS) for checking frame transmission errors. Here, the Intermediate FCS may be inserted before or inside the padding field. A wireless LAN terminal that has identified the Intermediate FCS may initiate at least one of channel switching, operation mode switching, and other operations without decoding to the end of the frame. When padding and the Intermediate FCS are used together in a MU-RTS TXS trigger frame (605), the time length from the point where the Intermediate FCS is inserted to the end of the padding may be set to a time length equal to or longer than the time length indicated by the DPS padding delay of the non-AP STA 1 (520).

[0204] When a non-AP STA 1 (520) operating as an initial LCM receives a MU-RTS TXS trigger frame (605) with the CS Required bit set to 0, the non-AP STA 1 (520) can transmit a CTS frame (606) without performing a CS operation according to the EDCA operation at the time when the operation mode transition from LCM to HCM is completed. The transmission bandwidth of the CTS frame (606) can use the entire bandwidth transmitted by the MU-RTS TXS trigger frame (605) based on the bandwidth information included in the previously received MU-RTS TXS trigger frame. In the above case, the AP (510) can transmit the MU-RTS TXS trigger frame (605) including padding. Here, the padding may be equal to the time length indicated by the DPS padding delay of non-AP STA 1 (520) or set to the time length of 'DPS padding delay of non-AP STA 1 (520) - SIFS'. As another example, AP (510) may transmit an Intermediate FCS along with padding in a MU-RTS TXS trigger frame (606). When padding and Intermediate FCS are used together in a MU-RTS TXS trigger frame (606), the time length from the point where the Intermediate FCS is inserted to the end of the padding may be equal to the time length indicated by the DPS padding delay of non-AP STA 1 (520) or set to the time length of 'DPS padding delay of non-AP STA 1 (520) - SIFS'.

[0205] non-AP STA 1 (520) can receive a MU-RTS TXS trigger frame (605) and complete the transition of its operating mode from LCM to HCM, and after completing the transition to HCM, respond to the AP (510) with a CTS frame (606) after a SIFS (Short Interframe Space) time. The CTS frame (606) may be transmitted within the total bandwidth in which the MU-RTS TXS trigger frame (605) was transmitted or using the maximum available bandwidth based on the bandwidth information contained in the MU-RTS TXS trigger frame (605). Here, the maximum available bandwidth may be within the bandwidth that the DPS STA can support.

[0206] After transmitting a CTS frame (606), non-AP STA 1 (520) can transmit a frame (e.g., a data frame) according to the TXS mode within the shared TXOP. For example, if AP (510) has shared the TXOP in TXS mode 1, non-AP STA 1 (520) can transmit a data frame (608) to AP (510) after transmitting a CTS frame (606). For another example, if AP (510) has shared the TXOP in TXS mode 2, non-AP STA 1 (520) can transmit a CTS frame (606) and transmit a data frame (608) to at least one of AP (510) and another non-AP STA (e.g., STA 2) within the BSS. Here, the frame transmitted by non-AP STA 1 (520) within the shared TXOP may be a frame using a bandwidth that is the same as or narrower than the bandwidth of the CTS frame (606) transmitted by non-AP STA 1 (520).

[0207] non-AP STA 1 (520) can switch to LCM at the time of TXOP termination when the TXOP shared by AP (510) is terminated. As another example, when the TXOP shared by AP (510) is terminated, non-AP STA 1 (520) can wait for additional frame reception for a certain period of time (e.g., SIFS time) after the TXOP termination time, and then switch to LCM if no frame is received. As yet another example, even if the TXOP shared by AP (510) is terminated, non-AP STA 1 (520) can operate as HCM until the time of TXOP termination of the first TXOP acquired by AP (510), and then switch to LCM at the time of TXOP termination of the first TXOP acquired by AP (510).

[0208] In the DPS operation of the non-AP STA 1 (520) described above, the conditions described in FIG. 3 and FIG. 7 may be applied as conditions for switching from HCM to LCM. Specifically, the operation may be switched to LCM based on at least one of the conditions for starting Tw in FIG. 3 and the conditions for starting Tw of the 'EMLSR operation' in FIG. 7. The Tw, <switching>, and <switching-receiving> described below may satisfy at least one of the Tw in FIG. 3 and the Tw of the 'EMLSR operation' in FIG. 7, and may not be limited to a specific form.

[0209] With the condition that the non-AP STA 1 (520) starts the Tw time at the time when it completes the transition from LCM to HCM after receiving a MU-RTS TXS trigger frame (605) from the AP (510) and responding with a CTS frame (606).<Tw 조건 1> This may correspond to. non-AP STA 1 (520) may wait without switching to LCM for Tw time. Afterwards, non-AP STA 1 (520) for Tw time<LCM 전환 조건> (or whether the <listening operation transition condition>) is satisfied can be checked. non-AP STA 1 (520) may have started the Tw time at the time the CTS frame transmission ended after the transition to HCM was completed, and during the Tw time described above<LCM 전환 조건> It may have been confirmed that it is not in a state corresponding to (or <listening operation switching condition>). Therefore, non-AP STA 1 (520) can transmit the first data frame (608) from HCM without switching from HCM to LCM.

[0210] At the time when non-AP STA 1 (520) receives a BA frame for the first data frame (608) after transmitting the first data frame (608), non-AP STA 1 (520) starts the Tw time of FIG. 3 (or the Tw time of the 'EMLSR operation' of FIG. 7) as a condition<Tw 조건 2> It may correspond to, and can wait without switching to LCM for Tw time. Afterwards, non-AP STA 1 (520) for Tw time<LCM 전환 조건> It can check whether the (or <listening operation switching condition>) is satisfied. The non-AP STA 1 (520) may start the Tw time at the time of end of reception of the BA frame for the first data frame (608). The non-AP STA 1 (520) may, during the aforementioned Tw time, transmit the second data frame (609) after SIFS time from the time of end of transmission of the BA frame for the first data frame (608).<LCM 전환 조건> It may be confirmed that the state does not correspond to (or <listening operation switching condition>). Therefore, non-AP STA 1 (520) can transmit the second data frame (609) from HCM without switching from HCM to LCM.

[0211] At the point when non-AP STA 1 (520) receives a BA frame from AP (510) after transmitting a second data frame (609), non-AP STA 1 (520) may wait without switching to LCM for the Tw time of FIG. 3 (or the Tw time of the 'EMLSR operation' of FIG. 7). Afterwards, non-AP STA 1 (520) during the Tw time<LCM 전환 조건> (or whether the <listening operation switching condition>) is satisfied can be checked. The non-AP STA 1 (520) may start the Tw time at the time of end of reception of the BA frame for the second data frame (609), and for the Tw time from the time of end of transmission of the BA frame for the second data frame (609).<LCM 전환 조건> It can be confirmed that the state corresponds to (or <listening operation switching condition>). Therefore, non-AP STA 1 (520) can switch the operation mode from HCM to LCM after the Tw time that started at the time of ending reception of the BA frame for the second data frame (609).

[0212] FIG. 12 is a diagram showing the TXS operation method of a wireless LAN dynamic power saving terminal applied to the present disclosure.

[0213] Referring to FIG. 12, the wireless LAN network may have an AP (510) and non-AP STAs, such as non-AP STA 1 (520) and non-AP STA 2 (530), but this is for convenience of explanation only and is not limited thereto. The non-AP STA 1 (520) and non-AP STA 2 (530) may operate by being associated with the AP (510). Additionally, the AP (510), non-AP STA 1 (520), and non-AP STA 2 (530) may be wireless LAN terminals that operate based on the EDCA operation of the wireless LAN terminal described above. That is, the AP (510), non-AP STA 1 (520), and non-AP STA 2 (530) perform channel access based on the EDCA backoff operation and channel access operation described above, and the wireless LAN terminal that succeeds in channel access can acquire a TXOP and transmit a frame. For example, the AP (510) and non-AP STA 1 (520) may be DPS STAs, which are DPS-supported wireless LAN terminals capable of operating based on the DPS operation of the wireless LAN terminal described above. Here, the non-AP STA 1 (520) may have negotiated the use of the DPS operation with the AP (510). Therefore, the non-AP STA 1 (520) may be operating as an initial LCM. The AP (510) and non-AP STA 1 (520) may be wireless LAN terminals that operate based on the TXS operation of the wireless LAN terminal of FIG. 8 described above. That is, AP (510) can share a portion of the TXOP it has acquired with non-AP STA 1 (520), and non-AP STA 1 (520) can transmit frames to AP (510) or another non-AP STA (e.g., STA 2) within the shared TXOP according to the TXS mode.

[0214] AP (510) may have initially acquired a TXOP by transmitting a CTS-to-Self frame (604). The CTS-to-Self frame (604) transmitted by AP (510) may be a frame in which the receiver address (RA) in the MAC header is set to the MAC address (e.g., BSSID) of AP (510). After transmitting the CTS-to-Self frame (604), AP (510) may exchange frames with other non-AP STAs (e.g., STA 1, STA 2) within the BSS within its TXOP. AP (510) may want to share a portion of its TXOP with other non-AP STAs (e.g., STA 1) within the BSS. For example, AP (510) may want to share a TXOP in at least one of the following cases: when there is no more data to transmit in its TXOP, when it recognizes that there is data to transmit to another non-AP STA in the BSS, when it recognizes that direct communication between other non-AP STAs in the BSS is necessary, or when another non-AP STA in the BSS requests AP (510) to share the TXOP, but is not limited thereto.

[0215] A method to resolve the ‘TXS bandwidth limiting problem’ described above in FIG. 9 may be considered. Specifically, the AP (510) may transmit an ICF (610) to switch the operating mode of a non-AP STA 1 (520) from LCM to HCM. The ICF (610) may be an RTS frame, a trigger frame (e.g., MU-RTS TXS trigger frame, Buffer Status Report Poll (BSRP)), and other frames, and is not limited to a specific form. The AP (510) may transmit the ICF (610) including an indicator that directs the switching of the operating mode from LCM to HCM.

[0216] The ICF (610) may be a frame that is duplicated and transmitted in a non-HT Duplicate PPDU format in 20 MHz units across the entire bandwidth of the TXOP acquired by the AP (510). If the bandwidth supported by the HCM of the DPS STA is smaller than the bandwidth of the TXOP acquired by the DPS STA, the AP (510) may transmit the ICF (610) with the bandwidth supported by the HCM of the DPS STA. The AP (510) may transmit the ICF (610) including an indicator that directs the operation mode transition from LCM to HCM. A non-AP STA 1 (520) operating in LCM initially may receive the aforementioned ICF (610) through the main 20 MHz channel and may recognize that it needs to switch its operation mode from LCM to HCM by checking the operation mode transition indicator included in the ICF (610).

[0217] The ICF (610) transmitted by the AP (510) may contain padding. The padding included in the ICF (610) may be intended to ensure the operating mode switching time of the non-AP STA 1 (520), and the length of the time may vary. Since the ICF (610) is a variant of a trigger frame, the AP (510) may set a CS Required bit to instruct the CS operation according to the EDCA operation to be performed when transmitting a response frame to the ICF (610). For example, the CS Required bit of the ICF (610) may be set to 1. In the above case, the non-AP STA 1 (520) may be required to perform the CS operation according to the EDCA operation for a SIFS (or PIFS) time when transmitting the ICR (611) as a response frame. The non-AP STA 1 (520) may transmit an ICR (611) as a response frame within the available bandwidth based on the result of the CS operation. As another example, the CS Required bit of the ICF may be set to 0. In the above case, the non-AP STA 1 (520) may not perform a CS operation based on the EDCA operation when transmitting the ICR (611) as a response frame, and the ICF (610) may transmit the ICR (611) within the received bandwidth. As an example, the ICR (611) may be a CTS frame, a Buffer Status Report (BSR), and other frames, and is not limited to a specific form.

[0218] Here, when a non-AP STA 1 (520) operating as an LCM receives an ICF (610) with the CS Required bit set to 1, the bandwidth of the CS operation performed by the non-AP STA 1 (520) according to the EDCA operation may be limited to the main 20 MHz channel. Taking the above into consideration, the AP (510) may transmit the ICF (610) with padding. The padding may be set to a time length equal to or longer than the time length indicating the DPS padding delay of the non-AP STA 1 (520). As another example, the AP (510) may transmit the ICF (610) with an Intermediate FCS before including padding. The Intermediate FCS may be in the form of a field or subfield containing all or part of the information of the Frame Check Sequence (FCS) for checking frame transmission errors. Here, the Intermediate FCS may be inserted before or inside the padding field. A wireless LAN terminal that detects the Intermediate FCS may initiate at least one of channel switching, operation mode switching, and other operations without decoding to the end of the frame. When padding and the Intermediate FCS are used together in the ICF (610), the time length from the point where the Intermediate FCS is inserted to the end of the padding may be set to a time length equal to or longer than the time length indicated by the DPS padding delay of the non-AP STA 1 (520).

[0219] On the other hand, if a non-AP STA 1 (520) operating as the first LCM receives an ICF (610) with the CS Required bit set to 0, the non-AP STA 1 (520) may transmit an ICR (611) as a response frame without performing a CS operation according to the EDCA operation at the time when the operation mode transition from LCM to HCM is completed. The transmission bandwidth of the ICR (611) may use the total bandwidth transmitted to the ICF (610) based on the bandwidth information included in the previously received ICF (610). In the above case, the AP (510) may transmit the ICF (610) including padding. Here, the padding may be equal to the time length indicated by the DPS padding delay of the non-AP STA 1 (520) or set to the time length of 'DPS padding delay of the non-AP STA 1 (520) - SIFS'. As another example, the AP (510) may transmit the Intermediate FCS along with padding in the ICF (610). When padding and the Intermediate FCS are used together in the ICF (610), the time length from the point where the Intermediate FCS is inserted to the end of the padding may be equal to the time length indicated by the DPS padding delay of the non-AP STA 1 (520) or set to the time length of 'DPS padding delay of the non-AP STA 1 (520) - SIFS'.

[0220] A non-AP STA 1 (520) can receive the ICF (610) and complete the transition of its operating mode from LCM to HCM, and after completing the transition to HCM, it can respond to the AP (510) with an ICR (611) after a SIFS (Short Interframe Space) time. The ICR (611) may be transmitted within the total bandwidth in which the ICF (610) was transmitted or using the maximum available bandwidth based on the bandwidth information contained in the ICF (610). Here, the maximum available bandwidth may be within the bandwidth that the DPS STA can support.

[0221] An AP (510) that receives an ICR (610) transmitted by a non-AP STA 1 (520) may transmit a MU-RTS TXS trigger frame (612) to share the AP's TXOP with the non-AP STA 1 (520). The MU-RTS TXS trigger frame (612) may be a frame that is duplicated in a non-HT Duplicate PPDU format in 20 MHz units across the entire bandwidth of the TXOP acquired by the AP (510). The AP (510) may include information in the MU-RTS TXS trigger frame (612) regarding the entire bandwidth over which the MU-RTS TXS trigger frame (612) is transmitted. Information regarding the total bandwidth of the MU-RTS TXS trigger frame (612) included in the MU-RTS TXS trigger frame (612) may be the bandwidth indicated by the UL (uplink) BW (bandwidth) field in the common info field within the MU-RTS TXS trigger frame (612).

[0222] Since the MU-RTS TXS trigger frame (612) is a variant of the trigger frame, a CS Required bit can be set to instruct the CS operation according to the EDCA operation to be performed when transmitting a response frame for the MU-RTS TXS trigger frame (612). For example, the CS Required bit of the MU-RTS TXS trigger frame (612) can be set to 1. In the above case, when the non-AP STA 1 (520) transmits the CTS frame (613) as a response frame, it may perform the CS operation according to the above-described EDCA operation for a SIFS (or PIFS) time. The non-AP STA 1 (520) may transmit the CTS frame within the available bandwidth according to the result of the CS operation. As another example, the CS Required bit of the MU-RTS TXS trigger frame (612) can be set to 0. In the above-described case, non-AP STA 1 (520) may not perform a CS operation according to the EDCA operation when transmitting a CTS frame (613) as a response frame, and may transmit the CTS frame (613) within the bandwidth in which the MU-RTS TXS trigger frame (612) was received. non-AP STA 1 (520) may receive the MU-RTS TXS trigger frame (612) and respond to the AP (510) with a CTS frame (613) after a SIFS (Short Interframe Space) time. non-AP STA 1 (520) may transmit the CTS frame (613) using the entire bandwidth in which the MU-RTS TXS trigger frame (612) was received or the maximum available bandwidth.

[0223] After transmitting the CTS frame (613), non-AP STA 1 (520) can transmit a frame (e.g., a data frame) according to the TXS mode within the shared TXOP. For example, if AP (510) shares the TXOP in TXS mode 1, non-AP STA 1 (520) can transmit a data frame (614) to AP (510) after transmitting the CTS frame (613). For another example, if AP (510) shares the TXOP in TXS mode 2, non-AP STA 1 (520) can transmit the CTS frame (613) and transmit a data frame (614) to at least one of AP (510) and another non-AP STA (e.g., STA 2) within the BSS. Here, the frame transmitted by non-AP STA 1 (520) within the shared TXOP may be a frame using a bandwidth that is the same as or narrower than the bandwidth of the CTS frame transmitted by non-AP STA 1 (520).

[0224] non-AP STA 1 (520) can switch to LCM at the time of TXOP termination when the TXOP shared by AP (510) is terminated. As another example, when the TXOP shared by AP (510) is terminated, non-AP STA 1 (520) can wait for additional frame reception for a certain period of time (e.g., SIFS time) after the TXOP termination time, and then switch to LCM if no frame is received. As yet another example, even if the TXOP shared by AP (510) is terminated, non-AP STA 1 (520) can operate as HCM until the time of TXOP termination of the first TXOP acquired by AP (510), and then switch to LCM at the time of TXOP termination of the first TXOP acquired by AP (510).

[0225] In the DPS operation of the non-AP STA 1 (520) described above, the conditions described in FIG. 3 and FIG. 7 may be applied as conditions for switching from HCM to LCM. Specifically, the operation may be switched to LCM based on at least one of the conditions for starting Tw in FIG. 3 and the conditions for starting Tw of the 'EMLSR operation' in FIG. 7. The Tw, <switching>, and <switching-receiving> described below may satisfy at least one of the Tw in FIG. 3 and the Tw of the 'EMLSR operation' in FIG. 7, and may not be limited to a specific form.

[0226] With the condition that the Tw time of FIG. 3 (or the Tw time of the 'EMLSR operation' of FIG. 7) starts at the time when non-AP STA 1 (520) receives the ICF (610) from the AP (510), completes the transition from LCM to HCM, and completes the transmission of the ICR (611).<Tw 조건 1> This may correspond to. non-AP STA 1 (520) may wait without switching to LCM for Tw time. Afterwards, non-AP STA 1 (520) during Tw time<LCM 전환 조건> (or whether the <listening operation switching condition>) is satisfied can be checked. The non-AP STA 1 (520) can start the Tw time at the end of the ICR (611) transmission, and during the Tw time<LCM 전환 조건> It may have been confirmed that it is not in a state corresponding to (or <listening operation switching condition>). Therefore, non-AP STA 1 (520) can complete reception of the MU-RTS TXS trigger frame (612) transmitted by the AP (510) in the HCM without switching from the HCM to the LCM.

[0227] non-AP STA 1 (520) may correspond to the condition of starting the Tw time of FIG. 3 (or the Tw time of the 'EMLSR operation' of FIG. 7) at the time when it has received the MU-RTS TXS trigger frame (612) and completed transmitting the CTS frame (613). non-AP STA 1 (520) may wait without switching to LCM for the Tw time. Afterwards, non-AP STA 1 (520) during the Tw time<LCM 전환 조건> (or whether the <listening operation switching condition>) is satisfied can be checked. The non-AP STA 1 (520) may start the Tw time at the time the CTS frame transmission ends after the switching to HCM is completed, and during the Tw time described above<LCM 전환 조건> It may have been confirmed that it is not in a state corresponding to (or <listening operation switching condition>). Therefore, non-AP STA 1 (520) can transmit the first data frame (614) from HCM without switching from HCM to LCM.

[0228] At the time when non-AP STA 1 (520) receives a BA frame for the first data frame (608) after transmitting the first data frame (608), non-AP STA 1 (520) starts the Tw time of FIG. 3 (or the Tw time of the 'EMLSR operation' of FIG. 7) as a condition<Tw 조건 2> It may correspond to, and can wait without switching to LCM for Tw time. Afterwards, non-AP STA 1 (520) for Tw time<LCM 전환 조건> (or whether the <listening operation switching condition>) is satisfied can be checked. The non-AP STA 1 (520) may start the Tw time at the time of end of reception of the BA frame for the first data frame (614). The non-AP STA 1 (520) may, during the aforementioned Tw time from the time of end of transmission of the BA frame for the first data frame (614).<LCM 전환 조건> (Or it may have been confirmed that it is in a state corresponding to <listening operation switching condition>). Therefore, non-AP STA 1 (520) can switch from HCM to LCM.

[0229] FIG. 13 is a diagram showing the TXS operation method of a wireless LAN dynamic power saving terminal applied to the present disclosure.

[0230] Referring to FIG. 13 and FIG. 9, the wireless LAN network may have an AP (510) and non-AP STAs, such as non-AP STA 1 (520) and non-AP STA 2 (530), but this is for convenience of explanation only and is not limited thereto. The non-AP STA 1 (520) and non-AP STA 2 (530) may operate by being associated with the AP. Additionally, the AP (510), non-AP STA 1 (520), and non-AP STA 2 (530) may be wireless LAN terminals that operate based on the EDCA operation of the wireless LAN terminal described above. That is, the AP (510), non-AP STA 1 (520), and non-AP STA 2 (530) perform channel access based on the EDCA backoff operation and channel access operation described above, and the wireless LAN terminal that succeeds in channel access can acquire a TXOP and transmit a frame. For example, the AP (510) and non-AP STA 1 (520) may be DPS STAs, which are DPS-supported wireless LAN terminals capable of operating based on the DPS operation of the wireless LAN terminal described above. Here, the non-AP STA 1 (520) may have negotiated the use of the DPS operation with the AP (510). Therefore, the non-AP STA 1 (520) may be operating as an initial LCM. The AP (510) and non-AP STA 1 (520) may be wireless LAN terminals that operate based on the TXS operation of the wireless LAN terminal of FIG. 8 described above. That is, AP (510) can share a portion of the TXOP it has acquired with non-AP STA 1 (520), and non-AP STA 1 (520) can transmit frames to AP (510) or another non-AP STA (e.g., STA 2) within the shared TXOP according to the TXS mode.

[0231] AP (510) may have initially acquired a TXOP by transmitting a CTS-to-Self frame (604). The CTS-to-Self frame (604) transmitted by AP (510) may be a frame in which the receiver address (RA) in the MAC header is set to the MAC address (e.g., BSSID) of AP (510). After transmitting the CTS-to-Self frame (604), AP (510) may exchange frames with other non-AP STAs (e.g., STA 1, STA 2) within the BSS within its TXOP. AP (510) may want to share a portion of its TXOP with other non-AP STAs (e.g., STA 1) within the BSS. For example, AP (510) may want to share a TXOP in at least one of the following cases: when there is no more data to transmit in its TXOP, when it recognizes that there is data to transmit to another non-AP STA in the BSS, when it recognizes that direct communication between other non-AP STAs in the BSS is necessary, or when another non-AP STA in the BSS requests AP (510) to share the TXOP, but is not limited thereto.

[0232] A method to solve the ‘TXS bandwidth limitation problem’ described above in FIG. 9 may be considered. Specifically, the AP (510) may transmit a MU-RTS TXS trigger frame (615) to share a TXOP with a non-AP STA 1 (520). Here, the MU-RTS TXS trigger frame (615) may be a frame that is duplicated in a non-HT Duplicate PPDU format in 20 MHz units across the entire bandwidth of the TXOP acquired by the AP (510). The AP (510) may include information in the MU-RTS TXS trigger frame (615) regarding the entire bandwidth over which the MU-RTS TXS trigger frame (615) is transmitted. The information regarding the total bandwidth in which the MU-RTS TXS trigger frame is transmitted, included in the MU-RTS TXS trigger frame (615), may be the bandwidth indicated by the UL (uplink) BW (bandwidth) field within the common info field in the MU-RTS TXS trigger frame. A non-AP STA 1 (520) operating as an LCM can receive the MU-RTS TXS trigger frame (615) on at least the main 20 MHz channel and can verify the bandwidth information (e.g., UL BW field) included in the MU-RTS TXS trigger frame (615). Through this, the non-AP STA 1 (520) can recognize the information regarding the total bandwidth in which the MU-RTS TXS trigger frame (615) is transmitted. The non-AP STA 1 (520) receives a MU-RTS TXS trigger frame (615) and can respond to the AP (510) with a CTS frame (616) after a short interframe space (SIFS) time. Since the CTS frame (616) is transmitted using the operating bandwidth used by the non-AP STA 1 (520) in the LCM, it can only be transmitted on the main 20 MHz channel.

[0233] non-AP STA 1 (520) may transmit a CTS frame (616) containing an indicator instructing to perform a mode switching operation from LCM to MCM in DPS operation. AP (510) can receive the CTS frame (616) transmitted by non-AP STA 1 (520) and check the aforementioned indicator included in the CTS frame (616). Thus, AP (510) can recognize that non-AP STA 1 (520) will switch the operation mode of non-AP STA 1 (520) from LCM to MCM after transmitting the CTS frame (616).

[0234] If non-AP STA 1 (520) does not perform frame transmission for a certain period of time (e.g., PIFS time after the last frame transmission) within the TXOP shared from AP (510), the AP (510) that shared its TXOP with non-AP STA 1 (520) can reclaim the TXOP. Here, if non-AP STA 1 (520) operating in LCM switches its operating mode to MCM and the time taken to switch is longer than the PIFS time, a problem may occur when the shared TXOP is reclaimed according to the TXOP reclamation condition described above. Accordingly, when non-AP STA 1 (520) instructs to switch its operation mode, AP (510) receives the CTS frame (616) transmitted by non-AP STA 1 (520) and may not retrieve the TXOP for the time of non-AP STA 1 (520)'s DPS padding delay or non-AP STA 1 (520)'s 'DPS padding delay + PIFS (Priority Interframe Space)' time. That is, AP (510) may wait without retrieving the TXOP until the non-AP STA 1 (520) completes the operation mode switch.

[0235] As another example, AP (510) may share a TXOP with a non-AP STA 1 (520) operating as an LCM even if there is no indicator within the CTS frame (616) instructing to perform a mode switching operation from LCM to MCM. In the above case, AP (510) may assume that the non-AP STA 1 (520) will start transmitting and receiving frames after switching to MCM. Accordingly, AP (510) may not retrieve the TXOP for the time of the non-AP STA 1 (520)'s DPS padding delay or the non-AP STA 1 (520)'s 'DPS padding delay (DPS padding delay + PIFS)' time after receiving the CTS frame (616) transmitted in response to the MU-RTS TXS trigger frame (615) that shares the TXOP. That is, AP (510) may wait without retrieving the TXOP until the non-AP STA 1 (520) completes the operation mode transition.

[0236] The result of the operation mode switching performed after non-AP STA 1 (520) transmits a CTS frame (616) in response to a MU-RTS TXS trigger frame (615) transmitted by AP (510) may vary. For example, non-AP STA 1 (520) may transmit a CTS frame (616) and perform a transition from LCM to HCM. For another example, non-AP STA 1 (520) may transmit a CTS frame and perform a transition from LCM to Medium Capability Mode (MCM). MCM may be an operation mode having an intermediate stage of operation capability between LCM and HCM, as a form of operation mode in which the DPS STA described above in FIG. 7 can operate. For example, the operating bandwidth of the MCM may be limited to a main 20 MHz channel, but the MCS, NSS, and other capabilities may use values ​​higher than those used in the LCM (e.g., intermediate MCS value, one or more NSS). However, it is not limited to this. When a DPS STA (non-AP STA 1 (520)) operating as an LCM or HCM switches its operating mode to the MCM, the operating mode switching time may be shorter than the time required to switch from LCM to HCM or from HCM to LCM (e.g., DPS Padding Delay, DPS Transition Delay). That is, AP (510) may not retrieve the TXOP for the expected operating mode transition time of non-AP STA 1 (520) (e.g., DPS Padding Delay or DPS Padding Delay + PIFS) after receiving the CTS frame (616) transmitted by non-AP STA 1 (520), but the start time of frame transmission by non-AP STA 1 (520) after the transmission of the CTS frame (616) may start at an earlier time than the operating mode transition time of non-AP STA 1 (520) expected by AP (510).

[0237] non-AP STA 1 (520) may have completed switching its operating mode from LCM to MCM after transmitting a CTS frame (616), and may transmit a frame (e.g., a data frame) according to the TXS mode within the shared TXOP. When switching from LCM to MCM, the bandwidth remains the same as LCM, and only the receivable MCS is changed, so the DPS operating mode change time may be shorter than the PIFS time, and the TXOP may not be recovered. For example, the DPS operating mode change time may be 0, SIFS, or PIFS, but is not limited thereto. When switching to MCM, non-AP STA 1 (520) transmits a CTS frame (616) while increasing the number of time-consuming NSS, and the first transmitted PPDU can be transmitted using only the capabilities switched up to that point.

[0238] For example, if AP (510) shares a TXOP in TXS mode 1, non-AP STA 1 (520) can transmit a data frame (617) to AP (510) after transmitting a CTS frame (616). For another example, if AP (510) shares a TXOP in TXS mode 2, non-AP STA 1 (520) can transmit a CTS frame (616) and transmit a data frame (617) to at least one of AP (510) and another non-AP STA (e.g., STA 2) in the BSS. The frame transmitted by non-AP STA 1 (520) within the shared TXOP may be a frame transmitted using the operational capability used by non-AP STA 1 (520) in the MCM (e.g., operational bandwidth of the Primary 20 MHz Channel, MCS with a value higher than LCM or / and NSS, etc.). That is, non-AP STA 1 (520) can transmit frames using a higher operating capability than LCM on the main 20 MHz channel that transmitted the CTS frame.

[0239] non-AP STA 1 (520) can switch to LCM at the time of TXOP termination when the TXOP shared by AP (510) is terminated. As another example, when the TXOP shared by AP (510) is terminated, non-AP STA 1 (520) can wait for additional frame reception for a certain period of time (e.g., SIFS time) after the TXOP termination time, and then switch to LCM if no frame is received. As yet another example, even if the TXOP shared by AP (510) is terminated, non-AP STA 1 (520) can operate as MCM until the time of TXOP termination of the first TXOP acquired by AP (510), and then switch to LCM at the time of TXOP termination of the first TXOP acquired by AP (510).

[0240] In the DPS operation of the non-AP STA 1 (520) described above, the conditions described in FIG. 3 and FIG. 7 may be applied as conditions for switching from MCM to LCM. Specifically, the operation may be switched to LCM based on at least one of the conditions for starting Tw in FIG. 3 and the conditions for starting Tw of the 'EMLSR operation' in FIG. 7. The Tw, <switching>, and <switching-receiving> described below may satisfy at least one of the Tw in FIG. 3 and the Tw of the 'EMLSR operation' in FIG. 7, and may not be limited to a specific form.

[0241] Specifically, as a condition to start Tw at the time when non-AP STA 1 (520) receives a BA frame for the data frame (617) after transmitting the data frame (617) following the completion of the transition from LCM to MCM.<Tw 조건 2> It may correspond to, and can wait without switching to LCM for Tw time. Afterwards, non-AP STA 1 (520) for Tw time<LCM 전환 조건> It can be checked whether the (or <listening operation switching condition>) is satisfied. The non-AP STA 1 (520) can start the Tw time at the time of termination of reception of the BA frame for the data frame (617), and during the Tw time described above<LCM 전환 조건> It can be confirmed that the state corresponds to (or <listening operation switching condition>). Therefore, non-AP STA 1 (520) can switch the operation mode from MCM to LCM after the Tw time that started at the time of ending reception of the BA frame for the data frame (617).

[0242] The above-described MCM may have lower power consumption than the HCM of non-AP STA 1 (520) in an operating mode with a lower upper limit of operating capability than the HCM of non-AP STA 1 (520). That is, when non-AP STA 1 (520) transmits and receives frames with the MCM, it may be possible for non-AP STA 1 (520) to reduce power consumption compared to the HCM. Additionally, non-AP STA 1 (520) may want to operate as an LCM as well as an MCM with a lower upper limit of operating capability than the HCM, and may want to perform P2P communication while performing power-saving operations. That is, when non-AP STA 1 (520) receives an ICF (e.g., MU-RTS trigger frame) from the AP (510), non-AP STA 1 (520) may transmit an ICR (e.g., CTS frame) to the AP (510). The ICR transmitted by non-AP STA 1 (520) may indicate that non-AP STA 1 (520) intends to perform frame transmission and reception with LCM. That is, non-AP STA 1 (520) may perform frame transmission and reception with LCM communication parameters as an upper limit within the shared TXOP of AP (510).

[0243] When non-AP STA 1 (520) operates as LCM within a shared TXOP, non-AP STA 1 (520) does not need to perform a mode switch after completing frame transmission and reception within the shared TXOP. AP (510) may be able to transmit frames up to the LCM communication parameters of non-AP STA 1 (520) immediately from the time the shared TXOP assigned to non-AP STA 1 (520) ends (or the time the shared TXOP is returned by non-AP STA 1 (520)).

[0244] Additionally, the AP (510) may include an indicator (e.g., remain in LC mode indicator) in the user info field or common info field of the ICF (e.g., MU-RTS TXS trigger frame) transmitted to the non-AP STA 1 (520) that causes the non-AP (510) STA 1 (520) to maintain an operating mode in LCM. In the above case, the bandwidth of the shared TXOP that the AP (510) allocates to the non-AP STA 1 (520) may be indicated as the upper limit of the bandwidth available to the non-AP STA 1 (520) in LCM.

[0245] For example, the AP (510) may add padding to the ICF to ensure that the non-AP STA 1 (520) has time to switch its operating mode from LCM to HCM. In the case described above, the non-AP STA 1 (520) may choose whether to operate as LCM or switch its operating mode from LCM to HCM. If the non-AP STA 1 (520) operates as LCM, the non-AP STA 1 (520) may send a CTS frame to the AP (510) with the operating bandwidth of the shared TXOP indicated by the AP (510). On the other hand, if the non-AP STA 1 (520) switches to HCM, the non-AP STA 1 (520) may send a CTS frame with a bandwidth greater than the operating bandwidth of the shared TXOP indicated by the AP (510) or indicate HCM, which is the current operating mode of the non-AP STA 1 (520), in the CTS frame.

[0246] As another example, AP (510) may not add padding to the ICF to ensure that non-AP STA 1 (520) can switch its operating mode from LCM to HCM. In the above case, non-AP STA 1 (520) can only operate as LCM. non-AP STA 1 (520) can operate as LCM or HCM within a shared TXOP.

[0247] If AP (510) does not transmit a CTS frame (e.g., a CTS to self frame) as the first frame of a TXOP, and the first frame of the TXOP is a MU-RTS TXS trigger frame that shares the TXOP with non-AP STA 1 (520), the transmission bandwidth of AP (510) may be constrained according to the CTS frame bandwidth of non-AP STA 1 (520). If the transmission bandwidth of the CTS frame is smaller than the transmission bandwidth of the MU-RTS TXS trigger frame, AP (510) may transmit and receive frames up to the transmission bandwidth of the CTS frame transmitted by non-AP STA 1 (520) after the shared TXOP is terminated or returned. Alternatively, the AP (510) may transmit and receive frames with the transmission bandwidth of the MU-RTS TXS trigger frame initially transmitted by the AP (510) within the TXOP as the upper limit, regardless of the transmission bandwidth of the non-AP STA 1 (520). Specifically, the AP (510) may transmit and receive frames with the transmission bandwidth of the MU-RTS TXS trigger frame as the upper limit without a separate channel detection procedure after the shared TXOP is terminated or returned. It may also be possible for the AP (510) to perform channel detection for a certain period of time (e.g., SIFS, PIFS time, etc.) after the shared TXOP is terminated or returned, and to transmit and receive frames using 20 MHz channels detected as idle.

[0248] FIG. 14 is a diagram showing the TXS operation method of a wireless LAN dynamic power saving terminal applied to the present disclosure.

[0249] Referring to FIG. 14, the wireless LAN network may have an AP (510) and non-AP STAs, such as non-AP STA 1 (520) and non-AP STA 2 (530), but this is for convenience of explanation only and is not limited thereto. The non-AP STA 1 (520) and non-AP STA 2 (530) may operate by being associated with the AP (510). Additionally, the AP (510), non-AP STA 1 (520), and non-AP STA 2 (530) may be wireless LAN terminals that operate based on the EDCA operation of the wireless LAN terminal described above. That is, the AP (510), non-AP STA 1 (520), and non-AP STA 2 (530) perform channel access based on the EDCA backoff operation and channel access operation described above, and the wireless LAN terminal that succeeds in channel access can acquire a TXOP and transmit a frame. For example, the AP (510) and non-AP STA 1 (520) may be DPS STAs, which are DPS-supported wireless LAN terminals capable of operating based on the DPS operation of the wireless LAN terminal described above. Here, the non-AP STA 1 (520) may have negotiated the use of the DPS operation with the AP (510). Therefore, the non-AP STA 1 (520) may be operating as an initial LCM.

[0250] AP (510) may transmit an ICF (618) to switch the operating mode of non-AP STA 1 (520) from LCM to HCM. The ICF (618) may be an RTS frame, a trigger frame (e.g., MU-RTS TXS trigger frame, Buffer Status Report Poll (BSRP)), and other frames, but is not limited to a specific form. AP (510) may transmit the ICF (618) including an indicator that directs the switching of the operating mode from LCM to HCM.

[0251] The ICF (618) may be a frame that is duplicated and transmitted in a non-HT Duplicate PPDU format in 20 MHz units across the entire bandwidth of the TXOP acquired by the AP (510). If the bandwidth supported by the HCM of the DPS STA is smaller than the bandwidth of the TXOP acquired by the DPS STA, the AP (510) may transmit the ICF (618) in the bandwidth supported by the HCM of the DPS STA. The AP (510) may transmit the ICF (618) including an indicator that directs the operation mode transition from LCM to HCM. A non-AP STA 1 (520) operating in LCM initially may receive the aforementioned ICF (618) through the main 20 MHz channel and may recognize that it needs to switch its operation mode from LCM to HCM by checking the operation mode transition indicator included in the ICF (618).

[0252] The ICF (618) transmitted by the AP (510) may contain padding. The padding included in the ICF (618) may be intended to guarantee the operating mode switching time of the non-AP STA 1 (520), and the length of the time may vary. Since the ICF (618) is a variant of a trigger frame, the AP (510) may set a CS Required bit to instruct the CS operation according to the EDCA operation to be performed when transmitting a response frame to the ICF. For example, the CS Required bit of the ICF (618) may be set to 1. In the above case, the non-AP STA 1 (520) may be required to perform the CS operation according to the EDCA operation for a SIFS (or PIFS) time when transmitting the ICR (619) as a response frame. The non-AP STA 1 (520) may transmit an ICR (619) as a response frame within the available bandwidth based on the result of the CS operation. As another example, the CS Required bit of the ICF (618) may be set to 0. In the above case, the non-AP STA 1 (520) may not perform a CS operation based on the EDCA operation when transmitting the ICR (619) as a response frame, and the ICF (618) may transmit the ICR (619) within the received bandwidth. As an example, the ICR (619) may be a CTS frame, a Buffer Status Report (BSR), and other frames, and is not limited to a specific form.

[0253] Here, when a non-AP STA 1 (520) operating as an LCM receives an ICF (618) with the CS Required bit set to 1, the bandwidth of the CS operation performed by the non-AP STA 1 (520) according to the EDCA operation may be limited to the main 20 MHz channel. Considering the above-mentioned problem, the AP (510) may transmit the ICF (618) with padding. The padding may be set to a time length equal to or longer than the time length indicating the DPS padding delay of the non-AP STA 1 (520). As another example, the AP (510) may transmit the ICF (618) with an Intermediate FCS before including padding. The Intermediate FCS may be in the form of a field or subfield containing all or part of the information of the Frame Check Sequence (FCS) for checking frame transmission errors. Here, the Intermediate FCS may be inserted before or inside the padding field. A wireless LAN terminal that detects the Intermediate FCS may initiate at least one of channel switching, operation mode switching, and other operations without decoding to the end of the frame. When padding and the Intermediate FCS are used together in the ICF (618), the time length from the point where the Intermediate FCS is inserted to the end of the padding may be set to a time length equal to or longer than the time length indicated by the DPS padding delay of the non-AP STA 1 (520).

[0254] On the other hand, if a non-AP STA 1 (520) operating as an initial LCM receives an ICF with the CS Required bit set to 0, the non-AP STA 1 (520) may transmit an ICR (618) as a response frame without performing a CS operation according to the EDCA operation at the time when the operation mode transition from LCM to HCM is completed. The transmission bandwidth of the ICR (619) may use the total bandwidth transmitted in the ICF (618) based on the bandwidth information included in the previously received ICF (618). In the above case, the AP (510) may transmit the ICF (618) including padding. Here, the padding may be equal to the time length indicated by the DPS padding delay of the non-AP STA 1 (520) or set to the time length of 'DPS padding delay of the non-AP STA 1 (520) - SIFS'. As another example, the AP (510) may transmit the Intermediate FCS along with padding in the ICF (618). When padding and the Intermediate FCS are used together in the ICF (618), the time length from the point where the Intermediate FCS is inserted to the end of the padding may be equal to the time length indicated by the DPS padding delay of the non-AP STA 1 (520) or set to the time length of 'DPS padding delay of the non-AP STA 1 (520) - SIFS'.

[0255] non-AP STA 1 (520) can receive the ICF (618) and complete the transition of its operating mode from LCM to HCM, and after completing the transition to HCM, it can respond to AP (510) with an ICR (619) after a SIFS (Short Interframe Space) time. The ICR (619) can be transmitted within the total bandwidth in which the ICF (619) was transmitted or using the maximum available bandwidth based on the bandwidth information contained in the ICF (618). AP (510) can receive the ICR (618) transmitted by non-AP STA 1 (520) and transmit a data frame (620) to non-AP STA 1 (520). The data frame (620) transmitted by AP (510) may be a frame using a bandwidth equal to or narrower than the bandwidth of the ICR transmitted by non-AP STA 1 (520).

[0256] AP (510) can set the RDG / MorePPDU bit of the MAC header HT control field in the data frame (620) transmitted to non-AP STA 1 (520) to 1. Upon receiving the data frame (620), non-AP STA 1 (520) can recognize that the RDG / MorePPDU bit is set to 1. In the above case, non-AP STA 1 (520) can recognize that reverse transmission is allowed. Reverse transmission may be an action in which the TXOP holder (AP (510) in FIG. 14) grants the TXOP responder (non-AP STA 1 (520) in FIG. 14) a data transmission opportunity. Non-AP STA 1 (520) can respond by receiving the data frame (620) and transmitting a BA frame (621) to AP (510) after SIFS time. The RDG / MorePPDU bit of the HT control field of the MAC header of the BA frame (621) transmitted by non-AP STA 1 (520) may be set to 1. AP (510) may recognize that the RDG / MorePPDU bit of the BA frame (621) transmitted by non-AP STA 1 (520) is set to 1 and may confirm that there is data to be transmitted by non-AP STA 1 (520) via reverse transmission. In the above case, AP (510) may wait for reception of the data frame (622) to be transmitted by non-AP STA 1 (520). non-AP STA 1 (520) may transmit the BA frame (621) and then transmit the data frame (622) to AP (510) after SIFS time.

[0257] After that, the RDG / MorePPDU bit of the HT control field of the MAC header of the data frame (622) transmitted by non-AP STA 1 (520) may be set to 0. AP (510) may recognize that the RDG / MorePPDU bit of the data frame (622) transmitted by non-AP STA 1 (520) is set to 0 and may confirm that non-AP STA 1 (520) no longer has any data to transmit in reverse transmission. AP (510) may receive the aforementioned data frame (622) and respond by transmitting a BA frame (623) to non-AP STA 1 (520) after SIFS time.

[0258] In the DPS operation of the non-AP STA 1 (520) described above, the conditions described in FIG. 3 and FIG. 7 may be applied as conditions for switching from HCM to LCM. Specifically, the operation may be switched to LCM based on at least one of the conditions for starting Tw in FIG. 3 and the conditions for starting Tw of the 'EMLSR operation' in FIG. 7. The Tw, <switching>, and <switching-receiving> described below may satisfy at least one of the Tw in FIG. 3 and the Tw of the 'EMLSR operation' in FIG. 7, and may not be limited to a specific form.

[0259] With the condition that non-AP STA 1 (520) starts the Tw time at the time when it completes the transition from LCM to HCM and completes the transmission of ICR after receiving the ICF (618) from the AP (510).<Tw 조건 1> This may correspond to. non-AP STA 1 (520) may wait without switching to LCM for Tw time. Afterwards, non-AP STA 1 (520) during Tw time<LCM 전환 조건> (or whether the <listening operation switching condition>) is satisfied can be checked. non-AP STA 1 (520) may have started the Tw time at the time the ICR (619) transmission ended, and during the Tw time<LCM 전환 조건> It may have been confirmed that it is not in a state corresponding to (or <listening operation switching condition>). Therefore, non-AP STA 1 (520) can complete receiving the data frame (620) transmitted by the AP (510) in the HCM without switching from the HCM to the LCM.

[0260] non-AP STA 1 (520) starts the Tw time at the time when it completes transmitting the BA frame (621) after receiving the data described above.<Tw 조건 1> This may correspond to. non-AP STA 1 (520) may wait without switching to LCM for Tw time. Afterwards, non-AP STA 1 (520) for Tw time<LCM 전환 조건> (or whether the <listening operation switching condition>) is satisfied can be checked. The non-AP STA 1 (520) can start the Tw time at the time the BA frame transmission ends after the switching to HCM is completed, and during the Tw time described above<LCM 전환 조건> It may be confirmed that the state does not correspond to (or <listening operation switching condition>). Therefore, non-AP STA 1 (520) can transmit a reverse data frame (622) from HCM without switching from HCM to LCM.

[0261] As a condition to start Tw at the point when non-AP STA 1 (520) receives a BA frame (623) from AP (510) after transmitting a reverse frame (622).<Tw 조건 2> It may correspond to, and can wait without switching to LCM for Tw time.

[0262] Afterwards, non-AP STA 1 (520) for Tw time<LCM 전환 조건> (or whether the <listening operation switching condition>) is satisfied can be checked. The non-AP STA 1 (520) can start the Tw time at the time of termination of reception of the BA frame (623) for the reverse data frame (622), and during the Tw time described above<LCM 전환 조건> It can be confirmed that the state corresponds to (or <listening operation switching condition>). Accordingly, non-AP STA 1 (520) can switch the operation mode from HCM to LCM after the Tw time that started at the time of ending reception of the BA frame (623) for the reverse data frame (622).

[0263] FIG. 15 is a flowchart illustrating the operation of an STA in a wireless LAN to which the present disclosure applies. Referring to FIG. 15, a first STA may operate based on a lower capability mode (LCM) (S1510). Here, the first STA may be a STA that performs an operation mode switching based on dynamic power saving (DPS). After that, the first STA may switch its operation mode from LCM to a higher capability mode (HCM) and operate (S1520). The first STA may share a transmit opportunity (TXOP) acquired by the second STA from the second STA, and if the switching condition is satisfied for a first predetermined time from a first point in time after the first STA has switched its operation mode to HCM, it may switch its operation mode from HCM to LCM (S1530). Here, the first STA may maintain HCM until the switching condition is satisfied in the shared TXOP. Here, the first time point may include at least one of the time point when the first STA completes transmitting a response frame for a frame received from another STA, the time point when it completes receiving a frame that does not require an immediate response from another STA, and the time point when the first STA completes transmitting a frame that does not require an immediate response. Additionally, if the first STA does not detect frame reception for a first preset time from the first time point, does not perform frame transmission, does not have a nonempty transmit queue, and does not schedule frame transmission, the switching condition is satisfied and the operation mode can be switched from HCM to LCM.In addition, the operating mode may be switched from HCM to LCM in any one of the following cases: when the first STA detects the reception of a frame for a first set time from a first time point but the recipient of the frame is not the first STA; when the first STA detects the reception of a trigger frame for a first set time from a first time point but the trigger frame does not allocate resources to the first STA; or when the first STA detects the reception of a CTS (clear to send) frame for a first set time from a first time point but the recipient address of the CTS frame is not the address of the access point (AP) connected to the first STA. In addition, when the first STA switches the operating mode from HCM to LCM, the operating mode switching may be performed during the mode switching time after the first set time from a first time point has elapsed, and the system may operate as HCM after the mode switching time. In addition, when the first STA receives an initial control frame (ICF) from the second STA that has acquired a TXOP, it switches the operation mode from LCM to HCM and transmits an initial control response (ICR). When the first STA receives a shared TXOP acquired by the second STA from the second STA, the first STA may maintain the HCM from a first time point until a first set time is satisfied. In addition, when the first STA receives an ICF from the second STA that has acquired a TXOP, it switches the operation mode from LCM to HCM and transmits an ICR. When the first STA receives a trigger frame allocating uplink resources from the second STA and performs frame transmission to the second STA, the first STA may maintain the HCM from a first time point until a first set time is satisfied.Additionally, the first STA receives a first frame that shares a TXOP from a second STA that has acquired a TXOP from an LCM, wherein the first frame is redundantly transmitted in at least one bandwidth including the bandwidth in which the first STA operates based on the LCM, and the first STA receives the shared TXOP acquired by the second STA based on the first frame, and can perform data frame transmission after transmitting a second frame as a response frame to the first frame. Additionally, the first frame includes information on the total bandwidth in which the first frame is transmitted, and the first STA can perform data frame transmission based on the total bandwidth information included in the first frame after transmitting a second response frame as a response frame to the first frame. Additionally, the second frame transmitted by the first STA includes an operation mode indicator, and the first STA switches the operation mode from the LCM to the HCM after transmitting the second frame, wherein the TXOP shared with the first STA can be retained without being recovered for a preset time based on the operation mode switching of the first STA. Additionally, the second frame transmitted by the first STA includes a padding field based on the operation mode switching of the first STA, and the first STA can perform frame transmission and reception in a shared TXOP by switching the operation mode from LCM to HCM before the transmission of the second frame is completed. Additionally, the first frame received by the first STA includes a padding field based on the operation mode switching of the first STA, and the first STA can perform frame transmission and reception in a shared TXOP by switching the operation mode from LCM to HCM before the reception of the first frame is completed. Additionally, the first STA receives an ICF containing a padding field from the LCM before receiving the first frame, switches the operation mode from LCM to HCM before the reception of the ICF is completed, and after transmitting an ICR in response to the ICF in the HCM, receives the first frame, and can share the TXOP from the second STA.Additionally, the first frame may be a MU-RTS TXS (multi-user-request to send TXOP sharing) trigger frame, and the second frame may be a CTS (clear to send) frame. Furthermore, in an LCM based on DPS operation, at least one of the operation bandwidth, the number of operation space streams, and the MCS (modulation and coding scheme) may be limited, or only the reception of an initial control frame may be possible, and in an HCM based on DPS operation, general transmit and receive operations may be possible. Additionally, the first STA may be a non-AP STA or an AP STA.

[0264]

[0265] The methods according to the present disclosure may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc., either alone or in combination. The program instructions recorded on the computer-readable medium may be those specifically designed and configured for the present disclosure, or they may be those known and available to those skilled in the art of computer software. Examples of computer-readable media include hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, etc. Examples of program instructions include machine code, such as that produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter, etc. The hardware devices described above may be configured to operate as at least one software module to perform the operations of the present disclosure, and vice versa. Although the present invention has been described with reference to the embodiments above, those skilled in the art will understand that various modifications and changes can be made to the present disclosure without departing from the spirit and scope of the disclosure as set forth in the following claims.

[0266]

[0267] The above-mentioned matters may also be applied to other systems.

Claims

1. In a method of operation of a first station (station, STA) in a wireless LAN system, A step in which the first STA operates based on LCM (lower capability mode), wherein the first STA is a STA that performs operation mode switching based on DPS (dynamic power saving); A step in which the first STA switches its operating mode from the LCM to the HCM (higher capability mode) and operates, wherein the first STA shares a transmit opportunity (TXOP) acquired by the second STA from the second STA; and A method of operation comprising the step of switching the operation mode from the HCM to the LCM when a switching condition is satisfied for a first set time from a first point in time after the first STA switches the operation mode to the HCM, wherein the first STA maintains the HCM until the switching condition is satisfied in the shared TXOP.

2. In Paragraph 1, A method of operation comprising at least one of the following: the first time point in which the first STA completes transmitting a response frame for a frame received from another STA, the time point in which the first STA completes receiving a frame that does not require an immediate response from another STA, and the time point in which the first STA completes transmitting a frame that does not require an immediate response.

3. In Paragraph 1, A method of operation in which the first STA does not detect frame reception, does not perform frame transmission, does not have a nonempty transmit queue, and does not schedule frame transmission, thereby satisfying the switching condition and switching the operation mode from the HCM to the LCM.

4. In Paragraph 3, A method of operation that switches the operation mode from the HCM to the LCM in any one of the following cases: the first STA detects the reception of a frame from the first time point to the first preset time, but the receiver of the frame is not the first STA; the first STA detects the reception of a trigger frame from the first time point to the first preset time, but the trigger frame does not allocate resources to the first STA; and the first STA detects the reception of a CTS (clear to send) frame from the first time point to the first preset time, but the receiver address of the CTS frame is not the address of the access point (AP) connected to the first STA.

5. In Paragraph 4, A method of operation in which, when the first STA switches the operation mode from the HCM to the LCM, the operation mode switching is performed during the mode switching time after the first previously set time has elapsed from the first point in time, and the operation is performed in the HCM after the mode switching time.

6. In Paragraph 1, A method of operation in which, when the first STA receives an initial control frame (ICF) from the second STA that has acquired a TXOP, the first STA switches the operation mode from the LCM to the HCM and transmits an initial control response (ICR), and when the second STA shares the TXOP acquired by the second STA, the first STA maintains the HCM from the first time point until the switching condition is satisfied for the first preset time.

7. In Paragraph 1, A method of operation in which, when the first STA receives an ICF from the second STA that has acquired a TXOP, it switches the operation mode from the LCM to the HCM and transmits an ICR, and when it receives a trigger frame allocating uplink resources from the second STA and performs frame transmission to the second STA, the first STA maintains the HCM from the first time point until the switching condition is satisfied for the first preset time.

8. In Paragraph 1, The first STA receives a first frame sharing a TXOP from the second STA that acquired a TXOP from the LCM, wherein the first frame is redundantly transmitted in at least one bandwidth including the bandwidth in which the first STA operates based on the LCM, and A method of operation in which the first STA shares the TXOP obtained by the second STA based on the first frame, transmits the second frame as a response frame to the first frame, and then performs data frame transmission.

9. In Paragraph 8, The first frame includes total bandwidth information in which the first frame is transmitted, and A method of operation in which the first STA transmits the second response frame as a response frame to the first frame, and then performs the transmission of the data frame based on the total bandwidth information included in the first frame.

10. In Paragraph 9, A method of operation in which the second frame transmitted by the first STA includes an operation mode indicator, and after transmitting the second frame, the first STA switches the operation mode from the LCM to the HCM, wherein the TXOP shared with the first STA is maintained without being retrieved for a preset time based on the operation mode switching of the first STA.

11. In Paragraph 9, A method of operation in which the second frame transmitted by the first STA includes a padding field based on the operation mode switching of the first STA, and the first STA switches the operation mode from the LCM to the HCM and performs frame transmission and reception in the shared TXOP until the transmission of the second frame is completed.

12. In Paragraph 9, A method of operation in which the first frame received by the first STA includes a padding field based on the operation mode switching of the first STA, and the first STA switches the operation mode from the LCM to the HCM and performs frame transmission and reception in the shared TXOP until the reception of the first frame is completed.

13. In Paragraph 9, A method of operation in which the first STA receives an ICF containing a padding field from the LCM before receiving the first frame, switches the operation mode from the LCM to the HCM until the reception of the ICF is complete, transmits an ICR in response to the ICF in the HCM, and then receives the first frame, shares a TXOP from the second STA.

14. In Paragraph 9, A method of operation in which the first frame is a MU-RTS TXS (multi-user-request to send TXOP sharing) trigger frame and the second frame is a CTS (clear to send) frame.

15. In Paragraph 1, A method of operation in which, in the LCM based on the above DPS operation, at least one of the operation bandwidth, the number of operation space streams, and the modulation and coding scheme (MCS) is limited or only the reception of an initial control frame is possible, and in the HCM based on the above DPS operation, general transmission and reception operation is possible.

16. In Paragraph 1, A method of operation in which the first STA is a non-AP STA or an AP STA.

17. In a wireless LAN system, regarding a station (STA), At least one transceiver for transmitting and receiving signals; At least one processor controlling the above-mentioned at least one transmitting and receiving unit; and It includes a memory that stores instructions for the non-AP STA to perform a specific operation by the above at least one processor, and The above specific operation is: It operates based on LCM (lower capability mode), wherein the first STA is an STA that performs operation mode switching based on DPS (dynamic power saving), and The above LCM operates by switching the operation mode to HCM (higher capability mode), wherein the STA shares the TXOP acquired by another STA from another STA; and A method of operation in which, after switching the operation mode to the above HCM, if a switching condition is satisfied for a first set time from a first point in time, the operation mode is switched from the above HCM to the above LCM, wherein the above STA maintains the above HCM until the switching condition is satisfied in the above shared TXOP.

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