Wireless LAN dynamic subchannel operation method and device

Abstract

In a wireless LAN system, a first STA transmits an ICF, wherein the ICF indicates a switching operation to at least one other STA, receives an initial control response (ICR) from the at least one other STA and receives the ICR, and then can transmit and / or receive data to and / or from the at least one STA.

Description

Wireless LAN Dynamic Subchannel Operation Method and Device

[0001] The present disclosure relates to a method and apparatus for a wireless local area network (WLAN) terminal performing a dynamic power saving (DPS) operation to perform a dynamic subchannel operation (DSO).

[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 for increased channel utilization. Furthermore, it can support a TXOP sharing method in which wireless LAN terminals share communication resources, specifically transmit opportunities (TXOPs), between access points (APs).

[0006] In addition, wireless LAN standards can support dynamic power save (DPS) methods, in which wireless LAN terminals (Stations, STAs) dynamically switch their operating modes to secure power saving performance. Furthermore, to increase the efficiency of communication resource utilization, wireless LAN standards can support dynamic subchannel operation (DSO), a method in which an AP can identify wireless LAN terminals that support only an operating bandwidth narrower than that of the AP within its BSS, and allocate a portion of the operating bandwidth to a subchannel (DSO channel) rather than the primary channel used for channel access to perform simultaneous transmission.

[0007] The following describes the operation considering the DPS operation mode switching time and the DSO channel switching time according to the aforementioned DPS operation and DSO channel switching operation.

[0008] 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.

[0009]

[0010] The present disclosure relates to a method and apparatus for a wireless LAN terminal performing a DPS operation in a wireless LAN to perform a DSO.

[0011] The present disclosure relates to a method and apparatus for minimizing or adjusting the delay time required for switching operation modes and switching operation channels when a DPS STA performs a DSO operation.

[0012] The present disclosure relates to a method and apparatus for adjusting the padding length within an initial control frame when operation mode switching and operation channel operation can be performed simultaneously.

[0013] 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.

[0014]

[0015] According to one embodiment of the present specification, a method of operation of a first station (STA) in a wireless LAN system may include the step of the first STA transmitting an initial control frame (ICF), wherein the ICF instructs at least one STA to perform a switching operation, the first STA receives an initial control response (ICR) from at least one STA, and after the first STA receives the ICR, perform at least one of transmitting and receiving data to and from at least one STA.

[0016] 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: transmitting an initial control frame (ICF), wherein the ICF instructs at least one other STA to perform a switching operation, receives an initial control response (ICR) from at least one other STA, and, after receiving the ICR, performs at least one of transmitting and receiving data to and from at least one STA.

[0017] In addition, the following points may apply in common.

[0018] According to one embodiment of the present specification, the switching operation indicated by the ICF may include at least one of a channel switching operation based on dynamic subchannel operation (DSO), a mode switching operation based on dynamic power saving (DPS), and a mode switching operation based on enhanced multi-link single radio (EMLSR).

[0019] Additionally, according to one embodiment of the present specification, the ICF includes a padding field, and the length of the padding field can be determined based on at least one switching operation by the ICF.

[0020] Additionally, according to one embodiment of the present specification, the padding field may be configured to correspond independently to each of at least one switching operation indicated by the ICF.

[0021] Additionally, according to one embodiment of the present specification, when the ICF instructs the second STA among at least one STA to perform a channel switching operation based on DSO and a mode switching operation based on DPS, the channel switching operation based on DSO and the mode switching based on DPS are performed in the second STA, wherein the time required for the channel switching operation based on DSO and the time required for the mode switching operation based on DPS in the second STA are required individually, and the length of the padding field of the ICF can be determined based on the sum of the time required for the channel switching operation based on DSO and the time required for the mode switching operation based on DPS.

[0022] Additionally, according to one embodiment of the present specification, when the ICF instructs the second STA among at least one STA to perform a channel switching operation based on DSO and a mode switching operation based on DPS, the channel switching operation based on DSO and the mode switching based on DPS are performed in the second STA, wherein the time required for the channel switching operation based on DSO and the time required for the mode switching operation based on DPS in the second STA are required simultaneously, and the length of the padding field of the ICF may be determined as the longer of the time required for the channel switching operation based on DSO and the time required for the mode switching operation based on DPS.

[0023] Additionally, according to one embodiment of the present specification, if the second STA among at least one STA receiving the ICF supports both DSO operation and DPS operation, and the third STA among at least one STA supports DSO operation, the first STA instructs the second STA to switch the operation mode based on DPS through the ICF, the first STA instructs the second STA through the ICF that the operation channel is maintained as the main channel, and the first STA instructs the third STA through the ICF to switch the operation channel based on DSO, thereby switching the operation channel of the third STA from the main channel to the DSO channel.

[0024] Additionally, according to one embodiment of the present specification, the length of the padding field of the ICF may be set to correspond to the longer of the time required for mode switching based on DPS in the second STA and the time required for channel switching based on DSO in the third STA, or the time required for mode switching based on DPS in the second STA and the time required for channel switching based on DSO in the third STA.

[0025] Additionally, according to one embodiment of the present specification, if the second STA among at least one STA receiving the ICF supports both DSO operation and DPS operation, and the third STA among at least one STA supports DSO operation, the first STA may instruct the second STA to switch the operation channel of the second STA from the main channel to the DSO channel through the ICF, and the first STA may instruct the second STA through the ICF that the operation mode based on DPS is maintained, and the first STA may instruct the third STA through the ICF that the operation channel of the third STA is maintained as the main channel.

[0026] Additionally, according to one embodiment of the present specification, the length of the padding field of the ICF may be set to correspond to the time required for channel switching based on the DSO in the second STA.

[0027] Additionally, according to one embodiment of the present specification, if a second STA among at least one STA receiving an ICF supports both DSO operation and DPS operation, and a third STA among at least one STA supports DSO operation, the first STA can instruct the second STA via the ICF to maintain an operation mode based on DPS and maintain an operation channel based on DSO, and instruct the third STA via the ICF to switch the operation channel based on DSO, thereby switching the operation channel of the third STA from the main channel to the DSO channel.

[0028] Additionally, according to one embodiment of the present specification, the length of the padding field of the ICF may be set to correspond to the time required for channel switching based on the DSO of the third STA.

[0029] Additionally, according to one embodiment of the present specification, if a second STA among at least one STA receiving an ICF supports both DSO operation and DPS operation, and a third STA among at least one STA supports DSO operation, the first STA may instruct the second STA via the ICF to switch operation modes based on DPS and switch operation channels based on DSO, and the first STA may instruct the third STA via the ICF that the operation channel of the third STA is maintained as the main channel.

[0030] Additionally, according to one embodiment of the present specification, the length of the padding field of the ICF may be set to correspond to the longer of the time required for mode switching based on DPS in the second STA and the time required for channel switching based on DSO in the second STA, or the time required for mode switching based on DPS in the second STA and the time required for channel switching based on DSO in the second STA.

[0031] Additionally, according to one embodiment of the present specification, the DPS operation may include a lower capability mode (LCM) in which at least one of the operating bandwidth, the number of operating space streams, and the modulation coding scheme (MCS) is limited or only the reception of an initial control frame is possible, and a higher capability mode (HCM) in which general transmission and reception operations are possible.

[0032] Additionally, according to one embodiment of the present specification, the DSO operation may be an operation that switches the operation channel from the main channel to the DSO channel to perform transmission and reception along with the main channel transmission.

[0033] Additionally, according to one embodiment of the present specification, the EMLSR operation mode may include a listening operation mode capable of receiving only an initial control frame in multiple links and a normal transmission / reception mode.

[0034] Additionally, according to one embodiment of the present specification, the first STA may be a non-AP STA or an AP STA.

[0035]

[0036] According to the present disclosure, a wireless LAN terminal performing a DPS operation in a wireless LAN can provide a method for performing a DSO.

[0037] According to the present disclosure, a method can be provided to minimize or adjust the delay time required for switching the operation mode and switching the operation channel when a DPS STA performs a DSO operation.

[0038] According to the present disclosure, a method for adjusting the padding length within an initial control frame can be provided when operation mode switching and operation channel operation can be performed simultaneously.

[0039] 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.

[0040] 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 pertains from the description below.

[0041]

[0042] FIG. 1 is a diagram showing a communication node within a wireless LAN system to which the present disclosure applies.

[0043] FIG. 2 is a drawing showing a wireless LAN system to which the present disclosure is applied.

[0044] FIGS. 3a and 3b are drawings illustrating a dynamic sub-channel operation method of a wireless LAN dynamic power saving terminal applied to the present disclosure.

[0045] FIGS. 4a and 4b are drawings illustrating a dynamic sub-channel operation method of a wireless LAN dynamic power saving terminal applied to the present disclosure.

[0046] FIGS. 5A and 5B are drawings illustrating a dynamic sub-channel operation method of a wireless LAN dynamic power saving terminal applied to the present disclosure.

[0047] FIG. 6 is a flowchart showing the operation of a STA in a wireless LAN to which the present disclosure applies.

[0048]

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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."

[0056] 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.

[0057] 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).

[0058] 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).

[0059] 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).

[0060] 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.

[0061] 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.

[0062] The following describes a method for allocating a DPS STA to a primary channel to minimize potential latency (e.g., operation mode switching time, operation channel switching time, etc.) when performing a DSO operation. Alternatively, a DPS STA may be allocated to a secondary channel (DSO channel) without switching its operation mode to minimize potential latency (e.g., operation mode switching time, operation channel switching time, etc.) when performing a DSO operation. Alternatively, when a DPS STA performs operation mode switching and operation channel switching, a method for determining the padding length to secure latency based on the implementation performance of the DPS STA is described.

[0063] In the following, a wireless LAN network configuration may be considered, but this is not intended to limit the scope of the present disclosure and may be a configuration for operations to be described later. For convenience of explanation, the term "wireless LAN network configuration" is used below, but it is not limited thereto.

[0064] In a wireless LAN network, at least one wireless LAN terminal capable of performing wireless LAN communication may operate. Here, the wireless LAN terminal may perform various roles. For example, the wireless LAN terminal may act as a wireless access point, and in the above-described case, the wireless LAN terminal may be referred to as an access point (AP). Alternatively, the wireless LAN terminal may be connected (associated) with an AP to perform wireless LAN communication, and in the above-described case, the wireless LAN terminal may be referred to as a non-AP STA. In this disclosure, AP 1 and non-AP STA are described based on STA 1 and STA 2, but this is merely a configuration for convenience of explanation and is not limited thereto.

[0065] An AP can configure a basic service set (BSS). A BSS may be a transmission range or communication area where an AP connects with a non-AP STA to perform communication. An AP can select a primary channel to use for channel access within the BSS and may specify the primary channel in frames transmitted by the AP (e.g., Beacon frames, Probe Response frames, etc.). A non-AP STA can establish a connection with the AP and access the channel by using the primary channel specified in the frames transmitted by the AP.

[0066] 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. The operating bandwidths of STA 1 and STA 2 may be more limited than those of AP 1. For example, AP 1 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 AP 1, but this is for convenience of explanation only and is not limited thereto.

[0067] 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.

[0068] Wireless LAN terminals (e.g., AP 1, 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, wireless LAN terminals (e.g., AP 1, 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 IFS (inter-frame space) length (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).

[0069] A wireless LAN terminal (e.g., AP 1, 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).

[0070] 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.

[0071] 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'.

[0072] EDCAF may want to access a wider bandwidth channel (broadband channel) including the main 20 MHz channel. To access the broadband channel, EDCAF may perform CCA on the main 20 MHz channel during AIFS[AC], wait for an additional slot time until BC becomes 0, and then transmit a frame including the broadband channel where the result of the CCA operation performed for a period equal to the PIFS (priority interframe space) time prior to the slot boundary where BC becomes 0 is idle. Alternatively, EDCAF may want to transmit a frame using only the main 20 MHz channel regardless of the CCA result of the broadband channel. In the above case, EDCAF may transmit a frame using only the main 20 MHz channel.

[0073] 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 1, 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.

[0074] 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 time length of the TXOP can be set to the time length from the time when the wireless LAN terminal (or the EDCAF of the corresponding AC within the wireless LAN terminal) completes the transmission of the first frame transmitted by the wireless LAN terminal until the time indicated by the duration / ID field of the MAC header within the frame. That is, the wireless LAN terminal (or the EDCAF of the corresponding AC within the wireless LAN terminal) that transmitted the first frame described above can perform transmit and receive operations from the time when the first frame transmission is completed until the time indicated by the duration / ID field of the MAC header within the first frame.

[0075] 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.

[0076] 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 coding scheme (MCS), etc.) between a lower capability mode (LCM) and a higher capability mode (HCM). That is, AP 1 and non-AP STA 1 may be DPS (dynamic power save) supported terminals (or DPS STAs). LCM may be an operational mode in which a 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 higher, all available spatial streams, highest MCS value, etc.). For example, a DPS STA operating in LCM mode (e.g., AP 1, non-AP STA 1) 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.

[0077] 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).

[0078] When a DPS STA dynamically switches its operating mode, the operation mode switching may require operation mode switching time. The operation mode switching time may include the mode switching time required for the mode switching operation from LCM to HCM and the mode switching back time required for the mode switching back operation from HCM to LCM. The aforementioned operation mode switching times (mode switching time and mode switching back time) may vary depending on the performance or operational capability of the DPS STA. Here, the DPS STA can exchange information regarding its maximum operational capability and operation mode switching time with other DPS STAs. For example, non-AP STA 1, which is a DPS-supported terminal, can exchange information regarding its maximum operational capability (e.g., 320 MHz operating bandwidth) and operation mode switching time with AP 1, which is a DPS STA. Here, non-AP STA 1 and AP 1 can be aware of each other's information regarding their maximum operational capability and operation mode switching time. Meanwhile, the above mode switching time may be referred to as DPS padding delay or padding delay, and the above mode switching back time may be referred to as DPS transition delay or transition delay, but is not limited to these names.

[0079] A DPS STA may be unable to perform transmit and receive operations during the operation mode switching time. That is, a DPS STA cannot perform frame transmit and receive operations during the mode switching time. Additionally, a DPS STA may not be able to perform operations for channel access (e.g., CCA) during the mode switching time. As another example, a DPS STA may perform frame transmit and receive operations using only the operational capabilities used by the LCM during the operation mode switching time, but is not limited to this.

[0080] For example, the mode switching operation described above may also be performed upon receiving a separate indicator. Here, the separate indicator may be a mode switching indicator or a mode switching back indicator that indicates mode switching. The AP may recognize a non-AP STA operating in LCM mode and may include and transmit a mode switching indicator within the ICF sent to the non-AP STA. Upon receiving the mode switching indicator, the non-AP STA may switch its operating mode from LCM to HCM.

[0081] Next, the wireless LAN terminal can perform dynamic subchannel operation (DSO). For the sake of convenience of explanation, the following description is based on the DSO operation of the wireless LAN terminal, but it may not be limited to these specific terms or names.

[0082] Dynamic subchannel operation (DSO) is an operation that an AP may use to increase channel efficiency. Specifically, the AP can identify non-AP STAs connected to the AP within the BSS and exchange information regarding the maximum operating bandwidth of the non-AP STAs during the connection process. For example, if the maximum operating bandwidth of the non-AP STAs is limited to the maximum operating bandwidth of the AP (e.g., the AP's maximum operating bandwidth is 320 MHz and the non-AP STA's maximum operating bandwidth is 80 MHz), the transmission bandwidth may be limited to the non-AP STA's maximum operating bandwidth (e.g., 80 MHz) when the AP transmits and receives data with the non-AP STA. In the above case, the remaining channels of the AP's maximum operating bandwidth (e.g., 320 MHz), excluding the 80 MHz bandwidth including the main channel, may not be used. Consequently, channel efficiency may be reduced.

[0083] An AP may use DSO operations to increase channel efficiency in the aforementioned situation. An AP using DSO operations may transmit an initial control frame (ICF) to non-AP STAs that have a more limited operational bandwidth than the AP within the BSS. The aforementioned ICF may include an operational channel switching indicator that instructs some of the non-AP STAs receiving the ICF to switch their operational channels to a subchannel (or DSO channel). The operational channel switching indicator may be an indicator that indicates the target subchannel (DSO channel) to which the non-AP STA receiving the ICF must switch. Additionally, the operational channel switching indicator may be an indicator that indicates the operational bandwidth used by the subchannel (DSO channel). A non-AP STA receiving the operational channel switching indicator may switch its operational channel to the subchannel (DSO channel) instructed by the AP. The aforementioned operating channel may refer to a channel used by a wireless LAN terminal to perform channel access, and may refer to at least one of a channel and bandwidth for transmitting and receiving data. Here, the ICF may be a frame of various forms. For example, the ICF may be at least one of a MU RTS (multi-user request-to-send), a BSRP (buffer status report poll), and other frames. Additionally, the ICF may be a frame that is redundantly transmitted in 20 MHz increments across the entire channel or bandwidth where the ICF is transmitted. As another example, the ICF may be a frame transmitted to match at least one of the operating channel and operating bandwidth expected to be used by the receiving wireless LAN terminal.

[0084] For example, a wireless LAN terminal (e.g., AP, non-AP STA) that supports and participates in the aforementioned DSO operation may be referred to as a DSO-supported wireless LAN terminal (DSO STA). A DSO STA may require an operation channel switching time to switch its operation channel to a sub-channel (DSO channel). Here, the operation channel switching time may be the channel switching time required for a channel switching operation to switch from the main channel to the sub-channel (DSO channel) and the channel switching back time required for a channel switch back operation to switch from the sub-channel (DSO channel) to the main channel. The operation mode switching time (at least one of the channel switching time and the channel switch back time) may vary depending on the performance of the DSO STA and the operation channel to be switched. Here, the DSO STA may exchange information regarding its maximum operation bandwidth and operation channel switching time with other DSO STAs. For example, a non-AP STA that is a DSO STA can exchange information about its maximum operating bandwidth (e.g., 80 MHz operating bandwidth) and operating channel switching time with another DSO STA, an AP. The AP that is a DSO STA and the non-AP STA that is a DSO STA can recognize each other's information about maximum operating bandwidth and operating capability switching time.

[0085] A DSO STA may be unable to perform transmit and receive operations during the operation channel switching time. That is, a DSO STA may not be able to perform frame transmit and receive during at least one of the channel switching time and the channel switching back time. Additionally, a DSO STA may not be able to perform operations for channel access (e.g., clear channel assessment (CCA)) during at least one of the channel switching time and the channel switching back time.

[0086] The AP may add padding to the transmitted ICF to guarantee the operating channel switching time of the aforementioned DSO STA. The padding may be used to extend the transmission time of the frame. For example, the padding may be included in at least one of the forms of a field, a subfield, a bit, or other forms within the frame. The AP may add an Intermediate FCS to extend the padding length or to advance the start time of operation of the recipient wireless LAN terminal (e.g., the time when the DSO STA begins switching the operating channel). An Intermediate FCS may mean that all or part of the FCS (frame check sequence) field, which is a frame error detection code included at the end of the frame, is inserted in the middle of the frame in the form of a field or a subfield. A wireless LAN terminal that receives an Intermediate FCS can confirm the normal reception of the frame even in the middle of receiving the frame and can start subsequent operations (e.g., the operation of the DSO STA switching the operating channel).

[0087] The length of the padding within the ICF transmitted by the aforementioned AP to the non-AP STA may vary. For example, the padding length may be set to a time length equal to or longer than the time elapsed from the time the MAC header of the ICF is received to the time elapsed from the non-AP STA's channel switching time. As another example, the padding length may be set to a time length equal to or longer than the time elapsed from the time the intermediate FCS is received to the time elapsed from the time the non-AP STA's channel switching time is received.

[0088] A non-AP STA that is a DSO STA receives an ICF transmitted by the AP and can identify the operation channel switching indicator within the received ICF. Through the above, the non-AP STA can successfully switch the operation channel to a sub-channel (DSO channel). In the above case, the non-AP STA can transmit an initial control response frame (ICR) to the AP after a short interframe space (SIFS) time from the time the ICF reception ends. The ICR may be a frame transmitted by the non-AP STA using the bandwidth (e.g., 80 MHz) specified in the operation channel (e.g., main channel, sub-channel (DSO channel)) specified by the operation channel switching indicator. Here, the ICR may be a frame of various forms. For example, the ICR may be at least one of a Simultaneous Clear-to-Send (S-CTS), a Buffer Status Report (BSR), and other frames, and is not limited to a specific form. The above-described ICR may be a frame that is redundantly transmitted in 20 MHz increments across the entire channel or bandwidth where the ICR is transmitted. As another example, the ICR may be a frame that is transmitted in accordance with at least one of the operating channel and operating bandwidth currently used by the wireless LAN terminal transmitting the ICR.

[0089] The AP can receive an ICR transmitted by a non-AP STA that has successfully switched the operating channel on the channel indicated by the operating channel switching indicator. The AP can identify the non-AP STA that transmitted the ICR. The AP can receive the ICR using at least one of the channel and bandwidth where the ICR was transmitted and transmit a frame (e.g., a Data frame) to the non-AP STA that transmitted the ICR after the SIFS time. The non-AP STA that received the frame transmitted by the AP can transmit an acknowledgment frame (e.g., an acknowledgment (ACK) frame, a Block Acknowledgement (BA) frame) to the AP using the operating channel indicated by the operating channel switching indicator and the indicated bandwidth.

[0090] The DSO operation described above can be performed for a time length indicated by the duration field of the ICF initially transmitted by the AP. That is, the DSO operation described above can be performed for the length of the TXOP obtained by the AP successfully accessing the channel through the EDCA operation. At the end of the TXOP obtained by the AP, the DSO STA that has switched the operating channel can perform a channel switching back operation to switch its operating channel from the sub-channel (DSO channel) to the main channel.

[0091] FIGS. 3a and 3b are drawings illustrating a dynamic sub-channel operation method of a wireless LAN dynamic power saving terminal applied to the present disclosure.

[0092] Referring to FIGS. 3a and 3b, the wireless LAN network configuration of FIGS. 3a and 3b may be as described above. Here, the wireless LAN terminal may acquire a TXOP if it successfully accesses the channel by performing the EDCA operation described above. Additionally, AP 1 (310) and non-AP STA 1 (320), which are wireless LAN terminals within the wireless LAN network in FIGS. 3a and 3b, may be DPS STAs that follow the DPS operation described above. Furthermore, AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330), which are wireless LAN terminals within the wireless LAN network in FIGS. 3a and 3b, may be DSO STAs that follow the DSO operation of the terminal described above, but this is for convenience of explanation only and is not limited thereto.

[0093] AP 1 (310) can recognize that non-AP STA 1 (320) and non-AP STA 2 (330) are operating with a limited operating bandwidth compared to AP 1 (310). For example, AP 1 (310) may have an operating bandwidth of up to 80 MHz, and non-AP STA 1 (320) and non-AP STA 2 (330) may each have an operating bandwidth of up to 40 MHz, but this is for convenience of explanation only and is not limited thereto. Additionally, non-AP STA 1 (320), which is a DPS STA, may operate as an LCM by performing the aforementioned DPS operation, and may operate with the operating bandwidth of non-AP STA 1 (320) limited to 20 MHz.

[0094] In the above-described situation, AP 1 (310) may use the above-described DSO operation to increase channel efficiency. AP 1 (310) may decide to perform simultaneous transmission and reception using different bands where non-AP STA 1 (320) and non-AP STA 2 (330) do not overlap. That is, AP 1 (310) may transmit an ICF to non-AP STA 1 (320) and non-AP STA 2 (330), and may include an operation channel switching indicator in the ICF to instruct non-AP STA 1 (320) or non-AP STA 2 (330) to switch the operation channel to a sub-channel (DSO channel). In the DSO operation, AP 1 (310) may redundantly transmit the same ICF in 20 MHz channel units to the full-band channel to be used with non-AP STA 1 (320) and non-AP STA 2 (330). non-AP STA 1 (320) and non-AP STA 2 (330) can receive an ICF transmitted over a main 20 MHz channel. However, non-AP STA 1 (320) may operate as an LCM based on DPS operation, and its operating bandwidth may be limited to 20 MHz. That is, this may mean that non-AP STA 1 (320) must communicate using a limited bandwidth independently of DSO operation. Taking the above into consideration, AP 1 (310) may transmit the ICF including a mode switching indicator. The mode switching indicator may be an indicator that instructs to change the mode from LCM to HCM. When non-AP STA 1 (320) receives the mode switching indicator in the ICF transmitted by AP 1 (310), non-AP STA 1 (320) may switch the operating capability of non-AP STA 1 (320) from LCM to HCM. That is, the non-AP STA 1 (320) can switch its operating mode to operate using its maximum operating bandwidth of 40 MHz.After performing the operation mode switch from LCM to HCM, non-AP STA 1 (320) can transmit an ICR to AP 1 (310) to indicate that the mode switching is complete. For example, when the DSO operation and the DPS mode switching operation are performed together, the ICR may be indicated to include the role of the ICR for the DSO operation.

[0095] As described above, when AP 1 (310) instructs non-AP STA 1 (320) to switch the operation mode and operation channel simultaneously, non-AP STA 1 (320) needs to consider both the delay time of the mode switching delay due to the DPS operation and the channel switching time due to the DSO operation. AP 1 (310) may transmit the ICF including padding corresponding to the time required for the operation so that non-AP STA 1 (320) can receive the ICF and have sufficient time to perform at least one of the DPS operation and the DSO operation.

[0096] Here, when AP 1 (310) instructs to perform DPS operations and DSO operations simultaneously, the padding length included in the ICF transmitted by AP 1 (310) may be extended to account for both DPS operations and DSO operations. As described above, the time required to complete the preparation for transmission and reception operations through DSO operations may be delayed, and a solution may be needed. That is, when DSO operations and DPS operations are performed simultaneously, a solution to minimize the padding length included in the ICF may be needed. Minimizing the padding length may mean minimizing the time required for channel switching or mode switching for DSO operations and DPS operations, thereby improving throughput.

[0097] Referring to FIG. 3a, AP 1 (310) can minimize the padding length included in the ICF. For example, when non-AP STA 1 (320) needs to perform a DPS operation along with a DSO operation, AP 1 (310) can instruct non-AP STA 1 (320) to communicate using the main channel so that it performs only the DPS mode switching without channel switching due to the DSO operation, thereby minimizing the time required. That is, when non-AP STA 1 (320) needs to perform both DSO and DPS operations, AP 1 (310) can instruct it to perform only the mode switching based on DPS as a single operation and not change the channel for the DSO operation. Specifically, AP 1 (310) can acquire a TXOP by successfully accessing the channel on the main channel through the EDCA operation described above. AP 1 (310) can redundantly transmit the same ICF (401) in 20 MHz channel units to the full band channel (operating bandwidth of AP 1 (e.g., 80 MHz)) to be used with non-AP STA 1 (320) and non-AP STA 2 (330) in DSO operation. non-AP STA 1 (320) and non-AP STA 2 (330) can receive the ICF (401) transmitted to the main 20 MHz channel. In the above case, the time length of the TXOP acquired by AP 1 (310) can be set to the time length from the time of completion of transmission of the ICF (401) transmitted by AP 1 (310) to the time indicated by the duration field in the MAC header of the ICF (401).

[0098] AP 1 (310) can use an indicator included in the transmitted ICF (401) to instruct non-AP STA 1 (320) not to perform channel switching operations of DSO operations, and to perform only mode switching operations of DPS operations. That is, AP 1 (310) can assign a channel (so that the channel is not changed) so that non-AP STA 1 (320), which is capable of performing two operations, performs only one operation. non-AP STA 1 (320) receives the ICF (401) and switches the operation mode from LCM to HCM, but may not switch the operation channel to the DSO channel. Here, the aforementioned indicator (an indicator instructing to perform mode switching operations of DPS operations or an indicator instructing to switch the mode from LCM to HCM) may be indicated by a specific bit or subfield of the user info field or common info field of the ICF (401), but is not limited thereto. As another example, the bandwidth allocated to the non-AP STA 1 (320) indicated by the user information field containing the non-AP STA 1 (320) identifier (e.g., association identifier (AID)) of the ICF (401) may be indicated as exceeding the operating bandwidth available to the non-AP STA 1 (320) in the LCM and is not limited to a specific form.

[0099] AP 1 (310) can use an indicator included in the transmitted ICF (401) to instruct non-AP STA 2 (330), which does not perform DPS operations, to perform channel switching operations of DSO operations. That is, AP 1 (310) can instruct non-AP STA 2 (330) to switch the operation channel to a sub-channel (DSO channel). AP 1 (310) can allocate the DSO channel so that each of the two terminals can perform only one operation. In the above case, the padding length included in the ICF transmitted by AP 1 (310) to non-AP STA 1 (320) and non-AP STA 2 (330) can be set based on the longer of the mode switching time performed by non-AP STA 1 (320) and the channel switching time performed by non-AP STA 2 (330). AP 1 (310) can set the padding length to 'padding part (e.g., padding field) transmission time + SIFS time' corresponding to the time length. As described above, the padding length in the ICF (401) transmitted by AP 1 (310) can be minimized.

[0100] Alternatively, the padding length included in the ICF (401) that AP 1 (310) transmits to non-AP STA 1 (320) and non-AP STA 2 (330) may be set to the length of the 'padding part (e.g., padding field) transmission time' for the duration of the longer of the mode switching time performed by non-AP STA 1 (320) and the channel switching time performed by non-AP STA 2 (330). That is, SIFS may not be taken into account in the calculation of the padding time length.

[0101] According to the operation described above, a padding length having a time length equal to or longer than the mode switching time or channel switching time that the STAs must perform in the DSO operation may be included in the ICF (401). For example, a non-AP STA 1 (320) may perform only the DPS operation mode switching and not the DSO channel switching. Therefore, AP 1 (310) may consider only the mode switching time of the non-AP STA 1 (320). Additionally, a non-AP STA 2 (330) may perform only the DSO channel switching and not the DPS operation mode switching. Therefore, AP 1 (310) may consider only the channel switching time of the non-AP STA 2 (330). AP 1 (310) determines the length of the padding field based on the longer switching time length between the mode switching time of the non-AP STA 1 (320) and the channel switching time of the non-AP STA 2 (330). As another example, AP 1 (310) may determine the padding field length based on the sum of the mode switching time of non-AP STA 1 (320) and the channel switching time of non-AP STA 2 (330), and is not limited to a specific form.

[0102] AP 1 (310) can set the padding field length of the ICF (401) transmitted to non-AP STA 1 (320) and non-AP STA 2 (330) to be the same based on the longer transition time length. Here, the ICF (401) transmitted by AP 1 (310) to non-AP STA 1 (320) and non-AP STA 2 (330) can be transmitted with the same content duplicated in 20 MHz increments. For example, the ICF (401) can be transmitted with the same content duplicated in 20 MHz increments based on a non-HT duplicate format. In a non-HT duplicate format, a non-HT PPDU format of the same content transmitted in 20 MHz increments can be transmitted simultaneously on each channel.

[0103] Referring to FIG. 3a, AP 1 (310) may have downlink data to be transmitted to non-AP STA 1 (320) and non-AP STA 2 (330). AP 1 (310) may switch non-AP STA 1 (320) to HCM to enable transmission over a wide bandwidth. At the same time, AP 1 (310) may move non-AP STA 2 (330) to a DSO channel to transmit data to non-AP STA 1 (320) and non-AP STA 2 (330) simultaneously. Accordingly, AP 1 (310) receives an ICR (402-1, 402-2) transmitted by non-AP STA 1 (320) and non-AP STA 2 (330) to the main 40 MHz channel and the secondary 40 MHz channel (DSO channel) (the same ICR can be transmitted redundantly in 20 MHz channel units or transmitted as a single ICR to the 40 MHz channel) and, after SIFS time, can simultaneously transmit data frames (403-1, 403-2) to non-AP STA 1 (320) and non-AP STA 2 (330).

[0104] Here, the data frames (403-1, 403-2) may be frames transmitted using the operating channel and operating bandwidth used by non-AP STA 1 (320) and non-AP STA 2 (330). non-AP STA 1 (320) and non-AP STA 2 (330) may receive the data frames (403-1, 403-2) transmitted by AP 1 (310) within their own operating channels and operating bandwidths. Each of non-AP STA 1 (320) and non-AP STA 2 (330) may receive the data frames (403-1, 403-2) and, after SIFS time, transmit a reception acknowledgment frame (e.g., BA frame) (404-1, 404-2) to AP 1 (310).

[0105] Additionally, non-AP STA 1 (320) can perform a DPS mode switching back operation at the end of the TXOP acquired by AP 1 (310). That is, non-AP STA 1 (320) can switch its DPS operation mode from HCM to LCM at the end of the TXOP acquired by AP 1 (310). non-AP STA 1 (320) can transmit a DPS mode switching indicator in a receive response frame indicating that the DPS operation is switched from HCM to LCM. AP 1 (310) can receive the DPS mode switching indicator included in the receive response frame transmitted by non-AP STA 1 (320). non-AP STA 2 (330) can perform a channel switching back operation at the end of the TXOP acquired by AP 1 (310). That is, non-AP STA 2 (330) can switch its operation channel from the sub-channel (DSO channel) to the main channel at the end of the TXOP acquired by AP 1 (310).

[0106] Here, for example, non-AP STA 1 (320) may not include a DPS mode switching indicator in the received response frame. non-AP STA 1 (320) and AP 1 (310) may be aware, by a prior rule, that if the DPS mode is switched from LCM to HCM at the start of the TXOP, it will be switched back from HCM to LCM at the end of the TXOP.

[0107] As another example, non-AP STA 1 (320) may determine that the TXOP is terminated if, from the time of completion of reception of the last frame received from AP 1 (310) that does not require an immediate response frame (or the time of completion of transmission of the last frame sent by STA 1 to AP 1) a frame is not detected (e.g., if STA 1 does not detect a frame and therefore does not generate the PHY-RXSTART.indication primitive). Alternatively, non-AP STA 1 (320) may determine that the TXOP has ended if, within a time of 'aSIFSTime + aSlotTime + aRxPHYStartDelay' from the time of completion of transmission of the last received frame from AP 1 (310) that does not require an immediate response frame (or the last frame transmitted by STA 1 to AP 1) (e.g., STA 1 detects the frame and generates a PHY-RXSTART.indication primitive), the recipient of the detected frame is not non-AP STA 1 (320) or the detected frame is not a frame that allocates uplink resources to non-AP STA 1 (320). When non-AP STA 1 (320) determines that the TXOP has ended, it may switch the operation mode from HCM to LCM, and the mode switch may take a time length equal to the mode switch delay time of non-AP STA 1 (320).AP 1 (310) can immediately transmit a frame to non-AP STA 1 (320) (i.e., immediately transmit a frame that limits the HCM operation capability of STA 1 on the main channel) at a time when 'aSIFSTime + aSlotTime + aRxPHYStartDelay' has not elapsed from the time when the transmission of a frame that does not require an immediate response frame to non-AP STA 1 (320) (or the time when the reception of the last frame received from STA 1 is completed). However, if that time has elapsed or if non-AP STA 1 (320) transmits a frame that is not a recipient or a frame that does not allocate uplink resources to non-AP STA 1 (320), non-AP STA 1 (320) may determine that the TXOP has ended and may take time to switch modes before it can receive (detect) a frame again.

[0108] AP 1 (310) cannot transmit a frame to which non-AP STA 1 (320) is the recipient within the mode switching delay time of non-AP STA 1 (320) from the time non-AP STA 1 (320) determines the end of the TXOP. AP 1 (310) can recognize that non-AP STA 1 (320) is operating as LCM again on the main channel after the mode switching delay time of non-AP STA 1 (320) has elapsed from the time non-AP STA 1 (320) determines the end of the TXOP, or thereafter. For example, AP 1 (310) can perform frame switching on the main channel by transmitting an ICF (e.g., an ICF that switches the operating mode of STA 1 from LCM to HCM) to non-AP STA 1 (320).

[0109] In a similar manner, the completion time of the operation channel switch of non-AP STA 2 (330) that has performed DSO channel switching can be considered. The case where non-AP STA 2 (330) has performed only DSO channel switching can be considered. non-AP STA 2 (330) can determine that the TXOP has ended if no frame is detected within a time of 'aSIFSTime + aSlotTime + aRxPHYStartDelay' from the completion time of receiving the last frame received from AP 1 (310) that does not require an immediate response frame (or the completion time of transmission of the last frame sent by non-AP STA 2 (330) to AP 1) (e.g., if non-AP STA 2 (330) does not generate the PHY-RXSTART.indication primitive). Alternatively, non-AP STA 2 (330) may determine that the TXOP has ended if it detects a frame within a time of 'aSIFSTime + aSlotTime + aRxPHYStartDelay' from the time of completion of transmission of the last frame received from AP 1 (310) that does not require an immediate response frame (or the last frame transmitted by STA 2 to AP 1) (e.g., STA 2 has generated a PHY-RXSTART.indication primitive), but the recipient of the detected frame is not non-AP STA 2 (330), or if the detected frame is not a frame that allocates uplink resources to non-AP STA 2 (330). When non-AP STA 2 (330) determines that the TXOP has ended, it may switch the operating channel from the DSO channel to the main channel, and the channel switching may take a time length equal to the channel switching time of non-AP STA 2 (330).AP 1 (310) may immediately transmit a frame to non-AP STA 2 (330) (i.e., immediately transmit on the DSO channel) at a time when 'aSIFSTime + aSlotTime + aRxPHYStartDelay' has not elapsed from the time when the transmission of a frame that does not require an immediate response frame to non-AP STA 2 (330) (or the time when the reception of the last frame received from STA 2 is completed). However, if AP 1 (310) has elapsed that time or if non-AP STA 2 (330) has transmitted a frame that is not a recipient or a frame that does not allocate uplink resources to non-AP STA 2 (330), non-AP STA 2 (330) may determine that the TXOP has ended and may take channel switching time. AP 1 (310) cannot transmit a frame to which non-AP STA 2 (330) is the recipient within the channel switching delay time of non-AP STA 2 (330) from the time non-AP STA 2 (330) determines the end of the TXOP. AP 1 (310) can know that non-AP STA 2 (330) is operating on the main channel again after the channel switching delay time of non-AP STA 2 (330) has elapsed from the time non-AP STA 2 (330) determines the end of the TXOP, and can perform frame exchange with non-AP STA 2 (330) on the main channel.

[0110] Additionally, referring to FIG. 3b, AP 1 (310) may use a method to minimize the padding length included in the ICF (401). For example, if AP 1 (310) needs to perform a DPS operation along with a DSO operation, AP 1 (310) may instruct non-AP STA 1 (320) not to perform a DPS operation mode switch. Specifically, AP 1 (310) can acquire a TXOP by successfully accessing the main channel through the aforementioned EDCA operation. AP 1 (310) may redundantly transmit the same ICF (401) in 20 MHz channel units to the full band channel (AP 1's operating bandwidth (e.g., 80 MHz)) to be used with non-AP STA 1 (320) and non-AP STA 2 (330) during the DSO operation. non-AP STA 1 (320) and non-AP STA 2 (330) can receive an ICF (401) transmitted over a main 20 MHz channel. In the above case, the time length of the TXOP acquired by AP 1 (310) can be set to the time length from the time of completion of transmission of the ICF (401) transmitted by AP 1 (310) to the time indicated by the duration field in the MAC header of the ICF (401).

[0111] AP 1 (310) can use an indicator included in the transmitted ICF (401) to instruct non-AP STA 1 (320) to operate as an LCM without performing a mode switching operation of a DPS operation. Through this, AP 1 (310) can instruct it to perform only a channel switching operation of a DSO operation. That is, AP 1 (310) can instruct non-AP STA 1 (320) to switch to a DSO channel. AP 1 (310) can transmit without including a DPS mode switching indicator if non-AP STA 1 (320) does not perform a mode switching of a DPS operation. Alternatively, AP 1 (310) may transmit an indicator to prevent the non-AP STA 1 (320) from performing a DPS mode transition, that is, the non-AP STA 1 (320) may not switch the operating mode from LCM to HCM after receiving the ICF (401). The aforementioned indicator may be indicated by a specific bit or subfield of the user info field or common info field of the ICF (401), but is not limited thereto. As another example, the bandwidth allocated to the non-AP STA 1 (320) indicated by the user info field of the ICF (401) containing the identifier (e.g., association identifier (AID)) of the non-AP STA 1 (320) may be indicated as exceeding the operating bandwidth available to the non-AP STA 1 (320) in the LCM, and is not limited to a specific form. Here, a padding field time length setting of the padding field of the ICF (401) may be an indicator that the padding field time length is shorter than the sum of the mode switching time and channel switching time of the non-AP STA 1 (320). That is, a padding field time length setting in which the non-AP STA 1 (320) can perform DSO channel switching but cannot perform operation mode switching may be an implicit indicator.

[0112] AP 1 (310) can assign non-AP STA 2 (330), which does not perform DPS operations, to the main channel using the indicator included in the transmitted ICF (401). If a DSO channel change is not required, AP 1 (310) may not include the DSO indicator or may transmit by designating the DSO assigned channel as the main channel. In the above case, the padding length included in the ICF (401) transmitted by AP 1 (310) to non-AP STA 1 (320) and non-AP STA 2 (330) may be set by referring to the time length value of the channel switching time for switching to the DSO channel performed by non-AP STA 1 (320). For example, the time required for the DPS mode switching of non-AP STA 1 (320) may be unnecessary, and only the channel switching time for switching to the DSO channel may be required. As described above, the padding length (i.e., the length of the padding field) transmitted by AP 1 (310) can be set to be the channel switching time. Therefore, the padding length within the ICF (401) transmitted by AP 1 (310) can be minimized. In the above case, non-AP STA 2 (330) can use the main 40 MHz channel and non-AP STA 1 (320) can perform frame transmission and reception using only the secondary 40 MHz 20 MHz channel.

[0113] As another example, AP 1 (310) can use an indicator included in the transmitted ICF (401) to cause non-AP STA 1 (320) to operate as an LCM without performing a mode switching operation of DPS operation. Additionally, AP 1 (310) can use an indicator included in the transmitted ICF (401) to assign a main channel so that non-AP STA 1 (320) does not perform a channel switching operation. At the same time, AP 1 (310) can use an indicator included in the transmitted ICF (401) to assign non-AP STA 2 (330) to a sub-channel (DSO channel). In the above-described case, the padding length included in the ICF (401) that AP 1 (310) transmits to non-AP STA 1 (320) and non-AP STA 2 (330) can be set such that 'padding transmission time + SIFS time' becomes the channel switching time (or a time longer than the channel switching time) by referring to the time length value of the channel switching time performed by non-AP STA 2 (330). That is, the padding length in the ICF (401) transmitted by AP 1 (310) can be minimized.

[0114] The ICF (401) transmitted by AP 1 (310) to non-AP STA 1 (320) and non-AP STA 2 (330) may be duplicated and transmitted in 20 MHz increments. For example, the ICF (401) duplicated in 20 MHz increments may be a non-HT duplicate format. Here, the non-HT duplicate format allows the non-HT PPDU format of the same content transmitted in 20 MHz increments to be transmitted simultaneously on each channel.

[0115] Referring to FIG. 3b, AP 1 (310) may have downlink data to be transmitted to non-AP STA 1 (320) and non-AP STA 2 (330). AP 1 (310) can keep non-AP STA 1 (320) in LCM mode and move non-AP STA 2 (330) to DSO channel to transmit data to non-AP STA 1 (320) and non-AP STA 2 (330) simultaneously. Accordingly, AP 1 (310) receives the ICR (405-1) transmitted by non-AP STA 1 (320) on the primary 20 MHz channel and the ICR (405-2) transmitted by non-AP STA 2 (330) on the secondary 40 MHz channel (DSO channel), and after SIFS time, can simultaneously transmit data frames (406-1, 406-2) to non-AP STA 1 (320) and non-AP STA 2 (330). Since non-AP STA 1 (320) uses the 20 MHz channel and non-AP STA 2 (330) uses the 40 MHz channel on the DSO channel, the 20 MHz channel that is not allocated in between may be punctured. Alternatively, the 20 MHz channel that is not allocated in between may be padded with any frame or the frame transmitted to non-AP STA 1 (320) may be repeated. The above-described data frames (406-1, 465-2) may be frames transmitted using the operating channel and operating bandwidth used by non-AP STA 1 (320) and non-AP STA 2 (330). non-AP STA 1 (320) and non-AP STA 2 (330) may receive data frames (406-1, 406-2) transmitted by AP 1 (310) within their own operating channel and operating bandwidth. non-AP STA 1 (320) and non-AP STA 2 (330) receive data frames (406-1, 406-2) and, after SIFS time, send a reception acknowledgment frame (e.g., to AP 1 (310)).BA frame) (407-1, 407-2) can be transmitted. Additionally, non-AP STA 2 (330) can perform a DSO channel switching back operation at the end of the TXOP acquired by AP 1 (310). That is, non-AP STA 1 (320) that has moved to the DSO channel can switch its operating channel from the sub-channel (DSO channel) to the main channel at the end of the TXOP acquired by AP 1 (310).

[0116] Referring to FIGS. 3a and 3b, when performing DSO operations including DPS terminals, the AP can assign the DPS terminals to the main channel. That is, terminals that do not perform DPS can move to the DSO channel. For example, to perform DSO operations with terminals that perform DPS and to minimize switching time, an indicator for switching the DPS operation mode may not be included. In other words, DPS mode switching should not be performed, and only DSO channel movement should be performed.

[0117] As another example, consider the case where non-AP STA 1 (320) only performs DSO channel switching. non-AP STA 1 (320) may determine that the TXOP is terminated if it is not detected within a time of 'aSIFSTime + aSlotTime + aRxPHYStartDelay' from the time when the last frame received from AP 1 (310) that does not require an immediate response frame is completed, or from the time when the last frame transmitted by non-AP STA 1 (320) to AP 1 (310) is completed (e.g., if STA 1 does not generate the PHY-RXSTART.indication primitive). Alternatively, non-AP STA 1 (320) may determine that the TXOP has ended if it detects a frame within a time of 'aSIFSTime + aSlotTime + aRxPHYStartDelay' from the time of completion of transmission of the last frame received from AP 1 (310) that does not require an immediate response frame (or the last frame transmitted by STA 1 to AP 1) (e.g., STA 1 has generated a PHY-RXSTART.indication primitive), but the recipient of the detected frame is not non-AP STA 1 (320) or the detected frame is not a frame that allocates uplink resources to non-AP STA 1 (320). When non-AP STA 1 (320) determines that the TXOP has ended, it may switch the operating channel from the DSO channel to the main channel, and the channel switching may take a time length equal to the channel switching time of non-AP STA 1 (320).AP 1 (310) may immediately transmit a frame to non-AP STA 1 (320) (i.e., immediately transmit on the DSO channel) at a time when 'aSIFSTime + aSlotTime + aRxPHYStartDelay' has not elapsed from the time of completion of transmission of a frame that does not require an immediate response frame to non-AP STA 1 (320) (or the time of completion of reception of the last frame received from STA 1). However, if such time has elapsed or if non-AP STA 1 (320) transmits a frame that is not for a recipient or a frame that does not allocate uplink resources to non-AP STA 1 (320), non-AP STA 1 (320) may determine that the TXOP has ended and may take channel switching time. AP 1 (310) cannot transmit a frame to which non-AP STA 1 (320) is the recipient within the channel switching delay time of non-AP STA 2 (330) from the time non-AP STA 1 (320) determines the end of the TXOP. AP 1 (310) can know that non-AP STA 1 (320) is operating on the main channel again after the channel switching delay time of non-AP STA 1 (320) has elapsed from the time non-AP STA 1 (320) determines the end of the TXOP, and can perform frame exchange with non-AP STA 1 (320) on the main channel.

[0118] As another example, AP 1 (310) may recognize that non-AP STA 1 (320) is a DPS STA. As described above, since non-AP STA 1 (320) may need to perform DSO operations and DPS operations simultaneously, AP 1 (310) may not involve non-AP STA 1 (320), which is a DPS STA, in the DSO operation. As an example, if AP 1 (310) recognizes that there is data to be exchanged with non-AP STA 1 (320) and non-AP STA 2 (330), AP 1 (310) may perform data exchange with non-AP STA 1 (320) by acquiring a separate TXOP to minimize the delay time (mode switching time, etc.) that may occur due to non-AP STA 1 (320), which is a DPS STA.

[0119] FIGS. 4a and 4b are drawings illustrating a dynamic sub-channel operation method of a wireless LAN dynamic power saving terminal applied to the present disclosure.

[0120] The wireless LAN network configuration of FIGS. 4a and 4b may be as described above. Here, the wireless LAN terminal may acquire a TXOP if it succeeds in accessing the channel by performing the EDCA operation described above. Additionally, AP 1 (310) and non-AP STA 1 (320), which are wireless LAN terminals within the wireless LAN network in FIGS. 4a and 4b, may be DPS STAs that follow the DPS operation described above. Furthermore, AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330), which are wireless LAN terminals within the wireless LAN network in FIGS. 4a and 4b, may be DSO STAs that follow the DSO operation of the terminal described above, but this is for convenience of explanation only and is not limited thereto.

[0121] AP 1 (310) can recognize that non-AP STA 1 (320) and non-AP STA 2 (330) are operating with a limited operating bandwidth compared to AP 1 (310). For example, AP 1 (310) may have an operating bandwidth of up to 80 MHz, and non-AP STA 1 (320) and non-AP STA 2 (330) may each have an operating bandwidth of up to 40 MHz, but may not be limited thereto. Additionally, non-AP STA 1 (320), which is a DPS STA, may operate as an LCM by performing the aforementioned DPS operation, and may operate with the operating bandwidth of non-AP STA 1 (320) limited to 20 MHz.

[0122] In the above-described situation, AP 1 (310) may use the above-described DSO operation to increase channel efficiency. AP 1 (310) may decide to perform simultaneous transmission and reception with non-AP STA 1 (320) and non-AP STA 2 (330) using different bands that do not overlap. Here, AP 1 (310) may transmit an ICF (408) to non-AP STA 1 (320) and non-AP STA 2 (330), and may include an operation channel switching indicator in the ICF (408) to instruct non-AP STA 1 (320) or non-AP STA 2 (330) to switch the operation channel to a sub-channel (DSO channel). AP 1 (310) can redundantly transmit the same ICF (408) in 20 MHz channel units to the full-band channel to be used with non-AP STA 1 (320) and non-AP STA 2 (330) in DSO operation. non-AP STA 1 (320) and non-AP STA 2 (330) can receive the ICF (408) transmitted to the main 20 MHz channel. However, non-AP STA 1 (320) may operate as LCM based on DPS operation, and its operating bandwidth may be limited to 20 MHz. That is, this may mean that non-AP STA 1 (320) must communicate using the limited bandwidth independently of DSO operation. Therefore, AP 1 (310) can transmit the ICF (408) including a mode switching indicator. The mode switching indicator may be an indicator that instructs to change the mode from LCM to HCM. When non-AP STA 1 (320) receives a mode switching indicator in the ICF (408) transmitted by AP 1 (310), non-AP STA 1 (320) can switch the operating capability of non-AP STA 1 (320) from LCM to HCM. That is, non-AP STA 1 (320) can switch the operating mode and operate using its maximum operating bandwidth of 40 MHz.After performing an operation mode switch from LCM to HCM, non-AP STA 1 (320) can transmit an ICR (409-1) to AP 1 (310) to indicate that the mode switching is complete. For example, when a DSO operation and a DPS mode switching operation are performed together, the ICR (409-1) can perform the role of the ICR for the DSO operation. As described above, when AP 1 (310) instructs non-AP STA 1 (320) to switch the operation mode and operation channel simultaneously, non-AP STA 1 (320) needs to consider both the delay time of the mode switching delay caused by the DPS operation and the channel switching time caused by the DSO operation.

[0123] AP 1 (310) can instruct non-AP STA 1 (320) to perform mode switching and channel switching. Specifically, AP 1 (310) can acquire a TXOP by successfully accessing the main channel through the aforementioned EDCA operation. In the DSO operation, AP 1 (310) can redundantly transmit the same ICF (408) in 20 MHz channel units to the full-band channel (AP 1's operating bandwidth (e.g., 80 MHz)) to be used with non-AP STA 1 (320) and non-AP STA 2 (330). non-AP STA 1 (320) and non-AP STA 2 (330) can receive the ICF (408) transmitted to the main 20 MHz channel. The time length of the TXOP obtained by AP 1 (310) can be set to the time length from the time of completion of transmission of the ICF (408) transmitted by AP 1 (310) to the time indicated by the duration field in the MAC header of the ICF (408).

[0124] AP 1 (310) may instruct non-AP STA 1 (320) to perform channel switching operations for DSO operations and mode switching operations for DPS operations through indicators included in the transmitted ICF (408). At the same time, AP 1 (310) may assign non-AP STA 2 (330), which does not perform DPS operations, to the main channel using indicators included in the transmitted ICF (408). In the above case, the ICF (408) transmitted by AP 1 (310) to non-AP STA 1 (320) and non-AP STA 2 (330) may include padding based on the delay time required for the DSO channel switching operations and DPS mode switching operations that non-AP STA 1 (320) must perform. For example, if a non-AP STA 1 (320) must perform DSO channel switching and DPS mode switching independently, the padding length may be set to the sum of the time required for the DSO channel switching and the time required for the DPS mode switching. That is, the padding included in the ICF (408) may each require padding considering the DSO channel switching and padding considering the DPS mode switching. Accordingly, the padding length may be determined as the sum of the time required for the DSO channel switching and the time required for the DPS mode switching. Additionally, even when other switching operations (e.g., EMLSR) are performed by the ICF (408), padding may be required separately from the padding considering the aforementioned DSO channel switching and DPS mode switching operations. That is, the padding of the ICF (408) may include padding considering each switching operation, and accordingly, the padding length may be determined as the sum of the times corresponding to the padding considering each switching operation, but is not limited thereto.

[0125] As another example, when non-AP STA 1 (320) performs DSO channel switching and DPS mode switching simultaneously, the padding length can be set to the longer of the time required for DSO channel switching and the time required for DPS mode switching.

[0126] Here, the padding length of the ICF (408) transmitted by AP 1 (310) may be set to be the longer of the sum of the mode switching time and channel switching time of non-AP STA 1 (320) or the mode switching time and channel switching time of non-AP STA 1 (320), as shown in FIG. 4a. Alternatively, the padding length of the ICF (408) transmitted by AP 1 (310) may be set to the length obtained by subtracting the SIFS time from the sum of the mode switching time and channel switching time of non-AP STA 1 (320) or the length obtained by subtracting the SIFS time from the longer of the mode switching time and channel switching time of non-AP STA 1 (320), as shown in FIG. 4b.

[0127] Alternatively, AP 1 (310) may set the padding length included in ICF (408) to be equal to the sum of the mode switching time and channel switching time of non-AP STA 1 (320) or to be the longer of the mode switching time and channel switching time of non-AP STA 1 (320), which may be as in FIG. 4a.

[0128] The ICF (408) transmitted by AP 1 (310) to non-AP STA 1 (320) and non-AP STA 2 (330) may be transmitted with identical content duplicated in 20 MHz increments. For example, the ICF (408) with identical content duplicated in 20 MHz increments may be a non-HT duplicate format. A non-HT duplicate format may mean that a non-HT PPDU format with identical content transmitted in 20 MHz increments is transmitted simultaneously on each channel.

[0129] According to the operation described above, in the case of a DSO operation, a padding length having a time length equal to or longer than the mode switching time or channel switching time to be performed at each STA may be included in the ICF. However, if a specific STA does not perform a mode switching or channel switching during a DSO operation, the specific STA's channel switching time or mode switching time may not be considered. On the other hand, if a specific STA performs both a mode switching and a channel switching during a DSO operation, both the specific STA's channel switching time and mode switching time must be considered. The consideration of both the specific STA's channel switching time and mode switching time may mean that when comparing the specific STA's switching time with another STA, the channel switching time and mode switching time are added together for comparison. Alternatively, when comparing the specific STA's switching time with another STA, the longer of the channel switching time and mode switching time may be compared with the other STA.

[0130] For example, when comparing the switching time of a specific STA with that of another STA, the channel switching time and the mode switching time may be added together for comparison. For example, a non-AP STA 1 (320) can perform both DPS operation mode switching and DSO channel switching. In the above case, AP 1 (310) may consider the sum of the mode switching and channel switching delays of the non-AP STA 1 (320) as the switching time of the non-AP STA 1 (320). For example, STA 3 and STA 4, which are DPS STAs, may be considered. STA 3 does not perform DSO channel switching but can perform DPS mode switching. In the above case, AP 1 (310) may consider only the mode switching time of STA 3. On the other hand, STA 4 does not perform DPS mode switching but can perform DSO channel switching. In the above case, AP 1 (310) may consider only the channel switching time of STA 4. Here, AP 1 (310) compares the sum of the mode switching time and channel switching time of non-AP STA 1 (320), the mode switching time of STA 3, and the channel switching time of STA 4, and AP 1 (310) can determine the padding length of ICF (408) based on the longest time among the three switching times and the time length that is equal to or longer than the longest time.

[0131] AP 1 (310) and non-AP STA 1 (320) can negotiate mutual capabilities during the association phase, which is a capability negotiation process. Here, AP 1 (310) can recognize the DSO channel switching time and DPS mode switching time of non-AP STA 1 (320), and can recognize whether they can be performed simultaneously or independently. Taking the above into account, AP 1 (310) can adjust the padding length of the ICF (408).

[0132] Referring to FIGS. 4a and 4b, AP 1 (310) may have downlink data to be transmitted to non-AP STA 1 (320) and non-AP STA 2 (330). AP 1 (310) may switch non-AP STA 1 (320) to HCM to enable transmission over a wide bandwidth. At the same time, AP 1 (310) may move non-AP STA 1 (320) to a DSO channel to transmit data to non-AP STA 1 (320) and non-AP STA 2 (330) simultaneously. Accordingly, AP 1 (310) receives an ICR (409-1, 409-2) transmitted by non-AP STA 1 (320) and non-AP STA 2 (330) to the main 40 MHz channel and the secondary 40 MHz channel (DSO channel) (the same ICR can be transmitted redundantly in 20 MHz channel units or transmitted as a single ICR to the 40 MHz channel) and, after SIFS time, can simultaneously transmit data frames (410-1, 410-2) to non-AP STA 1 (320) and non-AP STA 2 (330).

[0133] Here, the data frames (410-1, 410-2) may be frames transmitted using the operating channel and operating bandwidth used by non-AP STA 1 (320) and non-AP STA 2 (330). non-AP STA 1 (320) and non-AP STA 2 (330) may receive the data frames (410-1, 410-2) transmitted by AP 1 (310) within their own operating channels and operating bandwidths. Each of non-AP STA 1 (320) and non-AP STA 2 (330) may receive the data frames (410-1, 410-2) and, after SIFS time, transmit a reception acknowledgment frame (e.g., BA frame) (411-1, 411-2) to AP 1 (310).

[0134] Referring to FIGS. 4a and 4b, non-AP STA 1 (320) can perform the channel switching back operation of the DSO and the mode switching back operation of the DPS at the time of the end of the TXOP acquired by AP 1 (310). That is, non-AP STA 1 (320) can switch its operating channel to the main channel at the time of the end of the TXOP acquired by AP 1 (310), and after the channel switch, can switch its operating mode from HCM to LCM. As another example, non-AP STA 1 (320) can switch its operating mode from HCM to LCM at the time of the end of the TXOP acquired by AP 1 (310), and after the operating mode switch, can switch its operating channel to the main channel. Here, the time required for the switching back operation may be a value mutually negotiated between non-AP STA 1 (320) and AP 1 (310) during the connection phase, which is the capability negotiation process. Accordingly, AP 1 (310) can recognize the DSO channel switching back time and DPS switching back time of non-AP STA 1 (320), and can recognize whether they can be performed simultaneously or independently. As described above, AP 1 (310) can recognize whether non-AP STA 1 (320) operates in LCM mode on the main channel from a certain point in time.

[0135] As another example, non-AP STA 1 (320) can perform both DSO channel switching and DPS mode switching. non-AP STA 1 (320) can determine that the TXOP is terminated if no frame is detected within a time of 'aSIFSTime + aSlotTime + aRxPHYStartDelay' from the time of completion of receiving the last frame received from AP 1 (310) that does not require an immediate response frame (or the time of completion of transmission of the last frame sent by STA 1 to AP 1) (e.g., if STA 1 does not generate the PHY-RXSTART.indication primitive). Alternatively, non-AP STA 1 (320) may determine that the TXOP has ended if it detects a frame within a time of 'aSIFSTime + aSlotTime + aRxPHYStartDelay' from the time of completion of transmission of the last frame received from AP 1 (310) that does not require an immediate response frame (or the last frame transmitted by STA 1 to AP 1) (e.g., STA 1 generated a PHY-RXSTART.indication primitive), but the recipient of the detected frame is not non-AP STA 1 (320), or if the detected frame is not a frame that allocates uplink resources to non-AP STA 1 (320). When non-AP STA 1 (320) determines that the TXOP has ended, it may switch the operating channel from the DSO channel to the main channel. Additionally, non-AP STA 1 (320) may switch the operating mode from HCM to LCM. The operation channel switching may take as much time as the channel switching time of non-AP STA 1 (320), and the operation mode switching may take as much time as the operation mode switching time of non-AP STA 1 (320).In cases where the aforementioned switching operations are performed simultaneously (i.e., mode switching and channel switching can be performed in parallel), the point in time when non-AP STA 1 (320) can receive a frame by operating as an LCM on the main channel again may be the point in time when both the operation mode switching time and the channel switching time have elapsed from the point in time when non-AP STA 1 (320) determines the end of the TXOP. In cases where the aforementioned switching operations cannot be performed simultaneously, the point in time when non-AP STA 1 (320) can receive a frame by operating as an LCM on the main channel again may be the point in time when the sum of the operation mode switching time and the channel switching time has elapsed from the point in time when non-AP STA 1 (320) determines the end of the TXOP.

[0136] Meanwhile, AP 1 (310) may immediately transmit a frame to non-AP STA 1 (320) (i.e., immediately transmit on the DSO channel) at a time when 'aSIFSTime + aSlotTime + aRxPHYStartDelay' has not elapsed from the time when the transmission of a frame that does not require an immediate response frame to non-AP STA 1 (320) (or the time when the reception of the last frame received from STA 1 is completed). However, if that time has elapsed or if non-AP STA 1 (320) transmits a frame that is not for a recipient or a frame that does not allocate uplink resources to non-AP STA 1 (320), non-AP STA 1 (320) may determine that the TXOP has ended and may take channel switching time. AP 1 (310) cannot transmit a frame to which non-AP STA 1 (320) is the recipient until the time when non-AP STA 1 (320) can receive a frame by operating as LCM on the main channel again after the time when non-AP STA 1 (320) determines the end of the TXOP of non-AP STA 1 (320). AP 1 (310) can know that non-AP STA 1 (320) operates as LCM on the main channel again after the time when non-AP STA 1 (320) can receive a frame by operating as LCM on the main channel again, or thereafter. AP 1 (310) can perform frame exchange on the main channel by transmitting an ICF (e.g., an ICF that switches the operating mode of STA 1 from LCM to HCM) to non-AP STA 1 (320).

[0137] Additionally, in FIG. 4a, the time length for switching the operation channel from the main channel to the DSO channel after the non-AP STA 1 (320) switches from LCM to HCM based on the DPS operation may correspond to the time for padding. On the other hand, in FIG. 4b, the time length for switching the operation channel from the main channel to the DSO channel after the non-AP STA 1 (320) switches from LCM to HCM based on the DPS operation may correspond to the time for padding and SIFS combined, and other operations may be performed identically in FIG. 4a and FIG. 4b.

[0138] FIGS. 5A and 5B are drawings illustrating a dynamic sub-channel operation method of a wireless LAN dynamic power saving terminal applied to the present disclosure.

[0139] The wireless LAN network configuration of FIGS. 5a and 5b may be as described above. Here, the wireless LAN terminal may acquire a TXOP if it successfully accesses the channel by performing the EDCA operation described above. Additionally, AP 1 (310) and non-AP STA 1 (320), which are wireless LAN terminals within the wireless LAN network in FIGS. 5a and 5b, may be DPS STAs that follow the DPS operation described above. Furthermore, AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330), which are wireless LAN terminals within the wireless LAN network in FIGS. 5a and 5b, may be DSO STAs that follow the DSO operation of the terminal described above, but this is for convenience of explanation only and is not limited thereto.

[0140] AP 1 (310) can recognize that non-AP STA 1 (320) and non-AP STA 2 (330) are operating with a limited operating bandwidth compared to AP 1 (310). For example, AP 1 (310) may have an operating bandwidth of up to 80 MHz, and non-AP STA 1 (320) and non-AP STA 2 (330) may each have an operating bandwidth of up to 40 MHz, but may not be limited thereto. Additionally, non-AP STA 1 (320), which is a DPS STA, may operate as an LCM by performing the aforementioned DPS operation, and may operate with the operating bandwidth of non-AP STA 1 (320) limited to 20 MHz.

[0141] In the above-described situation, AP 1 (310) may use the above-described DSO operation to increase channel efficiency. AP 1 (310) may decide to perform simultaneous transmission and reception using different bands that do not overlap with non-AP STA 1 (320) and non-AP STA 2 (330). That is, AP 1 (310) may transmit an ICF (412) to non-AP STA 1 (320) and non-AP STA 2 (330), and may include an operation channel switching indicator in the ICF (412) to instruct non-AP STA 1 (320) or non-AP STA 2 (330) to switch the operation channel to a sub-channel (DSO channel). AP 1 (310) can redundantly transmit the same ICF (412) in 20 MHz channel units to the full-band channel to be used with non-AP STA 1 (320) and non-AP STA 2 (330) in DSO operation. non-AP STA 1 (320) and non-AP STA 2 (330) can receive the ICF (412) transmitted to the main 20 MHz channel. However, non-AP STA 1 (320) may operate as LCM based on DPS operation, and its operating bandwidth may be limited to 20 MHz. That is, this may mean that non-AP STA 1 (320) must communicate using the limited bandwidth independently of DSO operation. Therefore, AP 1 (310) can transmit the ICF including a mode switching indicator. The mode switching indicator may be an indicator that instructs to change the mode from LCM to HCM. When non-AP STA 1 (320) receives a mode switching indicator in the ICF (412) transmitted by AP 1 (310), non-AP STA 1 (320) can switch the operating capability of non-AP STA 1 (320) from LCM to HCM. That is, non-AP STA 1 (320) can switch the operating mode and operate using its maximum operating bandwidth of 40 MHz.After performing the operation mode switch from LCM to HCM, non-AP STA 1 (320) can transmit an ICR to AP 1 (310) to indicate that the mode switching is complete. For example, when the DSO operation and the DPS mode switching operation are performed together, the ICR can perform the role of the ICR for the DSO operation.

[0142] As described above, when AP 1 (310) instructs non-AP STA 1 (320) to switch the operation mode and operation channel simultaneously, non-AP STA 1 (320) needs to consider both the delay time of the mode switching delay due to the DPS operation and the channel switching time due to the DSO operation. AP 1 (310) may transmit ICF (412) with padding corresponding to the time required for the operation so that non-AP STA 1 (320) can receive ICF (412) and have sufficient time to perform at least one of the DPS operation and the DSO operation.

[0143] Here, if AP 1 (310) instructs the DPS operation and DSO operation to be performed simultaneously, the padding length included in the ICF (412) transmitted by AP 1 (310) may be increased. As described above, the time at which the transmission and reception operation is ready through the DSO operation may be delayed, and when the DSO operation and DPS operation are performed simultaneously, a method to minimize the padding length included in the ICF may be required. Minimizing the padding length may mean minimizing the time required for channel switching or mode switching for the DSO operation and DPS operation, thereby improving throughput.

[0144] Referring to FIG. 5a, AP 1 (310) can minimize the padding length included in the ICF (412). For example, if non-AP STA 1 (320) needs to perform a DPS operation along with a DSO operation, AP 1 (310) can minimize the time required by instructing non-AP STA 1 (320) to communicate using the main channel so that only the DPS mode switch is performed without the channel switching caused by the DSO operation. That is, if non-AP STA 1 (320) needs to perform both DSO and DPS operations, AP 1 (310) can instruct it to perform only one operation, DPS, and not change the channel for the DSO operation. Specifically, AP 1 (310) can obtain a TXOP by successfully accessing the channel on the main channel through the aforementioned EDCA operation. AP 1 (310) can redundantly transmit the same ICF (412) in 20 MHz channel units to the full band channel (operating bandwidth of AP 1 (e.g., 80 MHz)) to be used with non-AP STA 1 (320) and non-AP STA 2 (330) in DSO operation. non-AP STA 1 (320) and non-AP STA 2 (330) can receive the ICF (412) transmitted via the main 20 MHz channel. In the above case, the time length of the TXOP acquired by AP 1 (310) can be set to the time length from the time of completion of transmission of the ICF (412) transmitted by AP 1 (310) to the time indicated by the duration field in the MAC header of the ICF (412).

[0145] AP 1 (310) can use an indicator included in the transmitted ICF (412) to instruct non-AP STA 1 (320) not to perform channel switching operations of DSO operations, and to perform only mode switching operations of DPS operations. That is, AP 1 (310) must allocate a channel to non-AP STA 1 (320), which is capable of performing two operations, so that it can perform only one operation (so that the channel is not changed). At the same time, AP 1 (310) can use an indicator included in the transmitted ICF (412) to instruct non-AP STA 2 (330), which is not performing DPS operations, to perform channel switching operations of DSO operations and switch the operation channel to a sub-channel (DSO channel). That is, AP 1 (310) can allocate a DSO channel so that each of the two terminals can perform only one operation. In the above-described case, the padding length included in the ICF (412) that AP 1 (310) transmits to non-AP STA 1 (320) and non-AP STA 2 (330) can be set based on the longer of the mode switching time performed by non-AP STA 1 (320) and the channel switching time performed by non-AP STA 2 (330). AP 1 (310) can set the padding length to 'padding part (e.g., padding field) transmission time + SIFS time' corresponding to the time length. That is, the padding length in the ICF (412) transmitted by AP 1 (310) can be minimized.

[0146] Referring to FIG. 5a, AP 1 (310) can recognize that there is uplink data to be received from non-AP STA 1 (320) and non-AP STA 2 (330). Accordingly, AP 1 (310) can receive the ICR (413-1, 413-2) of non-AP STA 1 (320) and non-AP STA 2 (330) and, after SIFS time, send trigger frames (414-1, 414-2) to non-AP STA 1 (320) and non-AP STA 2 (330), respectively. The trigger frame (414-2) sent to non-AP STA 1 (320) may be duplicated with the same trigger frame per 20 MHz channel on the main 40 MHz channel. That is, the trigger frame (414-1) transmitted to non-AP STA 2 (330) and the trigger frame (414-2) transmitted to non-AP STA 1 (320) may have the same content and may include identifiers of non-AP STA 1 (320) and non-AP STA 2 (330) (e.g., Association Identifier (AID) of STA 1 and AID of STA 2). Alternatively, a single trigger frame may be transmitted over the main 40 MHz channel. The user information field of the trigger frame (414-2) transmitted to non-AP STA 1 (320) may include only the identifier of non-AP STA 1 (320) (e.g., Association Identifier (AID) of STA 1). Additionally, the trigger frame (414-2) may contain wireless resource information available to non-AP STA 1 (320) (e.g., resources corresponding to the Primary 40 MHz channel). Likewise, the trigger frame (414-1) transmitted by AP 1 (310) to non-AP STA 2 (330) may have the same trigger frame transmitted redundantly per 20 MHz channel to the secondary 40 MHz channel (40 MHz channel including the DSO channel).That is, the trigger frame (414-1) transmitted to non-AP STA 2 (330) and the trigger frame (414-2) transmitted to non-AP STA 1 (320) may have the same content. Alternatively, a single trigger frame (414-1) may be transmitted to a secondary 40 MHz channel (e.g., a 40 MHz channel including a DSO channel). The user field of the trigger frame (414-1) transmitted to non-AP STA 2 (330) may only contain the identifier of non-AP STA 2 (330) (e.g., the Association Identifier (AID) of STA 1). Additionally, the trigger frame (414-1) may contain wireless resource information available to non-AP STA 2 (330) (e.g., a resource corresponding to a secondary 40 MHz channel (DSO channel)). non-AP STA 1 (320) and non-AP STA 2 (330) can receive trigger frames (414-1, 414-2) transmitted by AP 1 (310) within their own operating channels and operating bandwidths. After receiving the trigger frames (414-1, 414-2), non-AP STA 1 (320) and non-AP STA 2 (330) can transmit data frames (415-1, 415-2) to the wireless resources allocated to AP 1 (310) after SIFS time. AP 1 (310) receives data frames (415-1, 415-2) transmitted by non-AP STA 1 (320) and non-AP STA 2 (330) and can transmit a reception acknowledgment frame (e.g., BA frame) (416-1, 416-2) to non-AP STA 1 (320) and non-AP STA 2 (330) after SIFS time.

[0147] non-AP STA 1 (320) can perform a DPS mode switching back operation at the time of termination of the TXOP acquired by AP 1 (310). That is, non-AP STA 1 (320) can switch its operation mode from HCM to LCM at the time of termination of the TXOP acquired by AP 1 (310). When the TXOP is terminated in the data frames (415-1, 415-2) transmitted as an uplink frame, non-AP STA 1 (320) can include a DPS mode switching indicator in the data frame (415-1) to indicate that the DPS operation is switched from HCM to LCM and transmit it. AP 1 (310) can receive the DPS mode switching indicator included in the data frame (415-1) transmitted by non-AP STA 1 (320). non-AP STA 2 (330) can perform a DPS channel switching back operation at the time of termination of the TXOP acquired by AP 1 (310). That is, non-AP STA 2 (330) can switch its operating channel from the sub-channel (DSO channel) to the main channel at the time of termination of the TXOP acquired by AP 1 (310). AP 1 (310) can determine that after the TXOP is terminated, non-AP STA 1 (320) is operating as LCM after the DPS mode switching back time, and non-AP STA 2 (330) is operating on the main channel after the DPS channel switching back time.

[0148] Referring to FIG. 5b, AP 1 (310) may use a method to minimize the padding length included in the ICF (412). For example, if AP 1 (310) needs to perform a DPS operation along with a DSO operation, AP 1 (310) may instruct non-AP STA 1 (320) not to perform a DPS operation mode switch. Specifically, AP 1 (310) can acquire a TXOP by successfully accessing the main channel through the aforementioned EDCA operation. AP 1 (310) may redundantly transmit the same ICF (412) in 20 MHz channel units to the full band channel (AP 1's operating bandwidth (e.g., 80 MHz)) to be used with non-AP STA 1 (320) and non-AP STA 2 (330) during the DSO operation. non-AP STA 1 (320) and non-AP STA 2 (330) can receive an ICF (412) transmitted over a main 20 MHz channel. In the above case, the time length of the TXOP acquired by AP 1 (310) can be set to the time length from the time of completion of transmission of the ICF (412) transmitted by AP 1 (310) to the time indicated by the duration field in the MAC header of the ICF (412).

[0149] AP 1 (310) can use an indicator included in the transmitted ICF to instruct non-AP STA 1 (320) to operate as an LCM without performing a mode switching operation of a DPS operation. Through this, AP 1 (310) can instruct it to perform only a channel switching operation of a DSO operation. That is, AP 1 (310) can instruct non-AP STA 1 (320) to switch to a DSO channel. That is, AP 1 (310) can instruct non-AP STA 1 (320) to switch to a DSO channel. If mode switching of a DPS operation is not performed, the transmission can be made without including a DPS mode switching indicator so that DPS mode switching does not occur. At the same time, AP 1 (310) can use an indicator included in the transmitted ICF to assign non-AP STA 2 (330), which does not perform a DPS operation, to the main channel. If a DSO channel change is not required, AP 1 (310) may transmit without including a DSO indicator or by designating the DSO assigned channel as the primary channel. In the above case, the padding length in the ICF (412) transmitted by AP 1 (310) may be equal to the value of the time length of the channel switching time performed by non-AP STA 1 (320). As another method of setting the padding length, the padding length included in the ICF transmitted by AP 1 (310) to non-AP STA 1 (320) and non-AP STA 2 (330) may be set to the time excluding the SIFS time from the channel switching time to the DSO channel performed by non-AP STA 1 (320). That is, the channel switching time may be set to 'Padding transmission time + SIFS time'. Through this, the padding length in the ICF transmitted by AP 1 (310) can be minimized.In the above case, non-AP STA 2 (330) can use the main 40 MHz channel and non-AP STA 1 (320) can use only the secondary 40 MHz 20 MHz channel to transmit and receive frames.

[0150] As another example, AP 1 (310) can use an indicator included in the transmitted ICF to cause non-AP STA 1 (320) to operate as an LCM without performing a mode switching operation of DPS operation, and can assign it to the main channel so that it does not perform a channel switching operation. At the same time, AP 1 (310) can use an indicator included in the transmitted ICF (412) to assign non-AP STA 2 (330) to the sub-channel (DSO channel). In the above case, the padding length in the ICF (412) transmitted by AP 1 (310) can be made to be equal to the time length value of the channel switching time performed by non-AP STA 2 (330). As another method for setting the padding length, the padding length included in the ICF that AP 1 (310) transmits to non-AP STA 1 (320) and non-AP STA 2 (330) can be set to the time excluding the SIFS time from the time of channel switching performed by non-AP STA 2 (320). That is, the channel switching time can be set to 'Padding transmission time + SIFS time'. Through this, the padding length in the ICF (412) transmitted by AP 1 (310) can be minimized.

[0151] Additionally, referring to FIG. 5b, AP 1 (310) may recognize that there is uplink data to be received from non-AP STA 1 (320) and non-AP STA 2 (330). Accordingly, AP 1 (310) may receive the ICR (417-1, 417-2) of non-AP STA 1 (320) and non-AP STA 2 (330) and, after SIFS time, transmit trigger frames (418-1, 418-2) to non-AP STA 1 (320) and non-AP STA 2 (330). The trigger frame (418-1) transmitted to non-AP STA 1 (320) may be transmitted over the main 20 MHz channel. The user information of the trigger frame (418-1) transmitted to non-AP STA 1 (320) may include only the identifier of non-AP STA 1 (320) and may include wireless resource information available to non-AP STA 1 (320) (e.g., resources corresponding to the main 20 MHz channel). The trigger frame (418-2) transmitted to non-AP STA 2 (330) may have the same trigger frame transmitted redundantly per 20 MHz channel to a secondary 40 MHz channel (e.g., a 40 MHz channel including a DSO channel, which is the bandwidth supported by the terminal). Alternatively, a single trigger frame may be transmitted to a secondary 40 MHz channel (e.g., a 40 MHz channel including a DSO channel). The user information of the trigger frame (418-2) transmitted to non-AP STA 2 (330) contains only the identifier of non-AP STA 2 (330) and includes wireless resource information available to non-AP STA 2 (330) (resources corresponding to the Secondary 40 MHz channel (DSO channel)). The secondary 20 MHz channel may be punctured as there are no frames to transmit. Alternatively, the 20 MHz channel that is not allocated in the middle may be padded with any frame or the frame transmitted to non-AP STA 1 (320) may be repeatedly transmitted.non-AP STA 1 (320) and non-AP STA 2 (330) can receive trigger frames (418-1, 418-2) transmitted by AP 1 (310) within their operating channels and operating bandwidths, and can transmit data frames (419-1, 419-2) to AP 1 (310) after SIFS time has passed since receiving the trigger frames. AP 1 (310) can receive data frames (419-1, 419-2) transmitted by non-AP STA 1 (320) and non-AP STA 2 (330) and can transmit acknowledgment frames (e.g., BA frames) (420-1, 420-2) to non-AP STA 1 (320) and non-AP STA 2 (330) after SIFS time has passed. Additionally, non-AP STA 2 (330) can perform a channel switching back operation at the end of the TXOP acquired by AP 1 (310). That is, non-AP STA 2 (330) can switch its operating channel from the sub-channel (DSO channel) to the main channel at the end of the TXOP acquired by AP 1 (310).

[0152] In the above-described FIGS. 3a to 5b, mode switching time may be required when switching from HCM to LCM or from LCM to HCM of the non-AP STA 1 (320), which is a DPS STA. Similarly, the non-AP STA 1 (320) can perform an EMLSR (enhanced multi-link single radio) operation. Although the above description was made based on a DPS STA for convenience of explanation, the same applies to EMLSR operation. That is, in the operation of FIGS. 3a to 5b described above, the operation of switching from LCM to HCM as a DPS operation switch can be replaced by an operation of switching between listening operation and normal transmission / reception operation as an EMLSR operation, and can be applied in the same way.

[0153] When non-AP STA 1 (320) performs an EMLSR operation, non-AP STA 1 (320) may basically operate in a listening operation. The operation described above may be similar to the LCM operation of the DPS operation, but is not limited thereto. Here, non-AP STA 1 (320) may only be able to receive an initial control frame (ICF). AP 1 (310) may transmit an ICF to non-AP STA 1 (320), and the padding field of the ICF transmitted to non-AP STA 1 (320) may be set such that the length of the padding field is equal to or longer than the EMLSR mode transition time, taking into account the EMLSR operation transition time of non-AP STA 1 (320) (i.e., the operation transition time when non-AP STA 1 (320) switches the operation mode from listening mode to EMLSR mode). When non-AP STA 1 (320) receives the ICF of AP 1 (310), it can switch its operation from a listening operation to a normal transmit / receive operation. After the STA switches to a normal transmit / receive operation, non-AP STA 1 (320) and AP 1 (310) can perform frame exchange. The normal transmit / receive operation is an operation in which non-AP STA 1 (320) can receive frames other than the ICF according to the operating capability of non-AP STA 1 (320), and may be an operation similar to the HCM operation of the DPS, but is not limited thereto.

[0154] non-AP STA 1 (320) can determine that the TXOP is terminated if it does not detect a frame within a time of 'aSIFSTime + aSlotTime + aRxPHYStartDelay' from the time when the last frame received from AP 1 (310) that does not require an immediate response frame is completed (or the time when the last frame transmitted by STA 1 to AP 1 is completed) (e.g., if STA 1 does not generate a PHY-RXSTART.indication primitive). Alternatively, non-AP STA 1 (320) may determine that the TXOP has ended if it detects a frame within a time of 'aSIFSTime + aSlotTime + aRxPHYStartDelay' from the time of completion of transmission of the last frame received from AP 1 (310) that does not require an immediate response frame (or the last frame transmitted by STA 1 to AP 1) (e.g., STA 1 generated a PHY-RXSTART.indication primitive), but the receiver of the detected frame is not non-AP STA 1 (320) or the detected frame is not a frame that allocates uplink resources to non-AP STA 1 (320). When non-AP STA 1 (320) determines that the TXOP has ended, it may switch the EMLSR operation from a normal transmit / receive operation to a listening operation. Here, the time required for the EMLSR operation switching of non-AP STA 1 (320) may be taken. The point in time when non-AP STA 1 (320) can receive a frame in the listening operation again is the point in time when the EMLSR operation mode switching time has elapsed from the point in time when non-AP STA 1 (320) determines the end of the TXOP.

[0155] Meanwhile, AP 1 (310) may immediately transmit a frame to non-AP STA 1 (320) at a time when 'aSIFSTime + aSlotTime + aRxPHYStartDelay' has not elapsed since the time when the transmission of a frame that does not require an immediate response frame to non-AP STA 1 (320) (or the time when the reception of the last frame received from STA 1 is completed). However, if that time has elapsed or if non-AP STA 1 (320) transmits a frame that is not a recipient or a frame that does not allocate uplink resources to non-AP STA 1 (320), non-AP STA 1 (320) may determine that the TXOP has ended and the EMLSR operation transition time may be required. AP 1 (310) cannot transmit a frame to which non-AP STA 1 (320) is the recipient until the time when non-AP STA 1 (320) can receive a frame again in a listening operation on the main channel after the time when non-AP STA 1 (320) determines the end of the TXOP of non-AP STA 1 (320). AP 1 (310) can determine that non-AP STA 1 (320) can receive a frame again in a listening operation after the time when non-AP STA 1 (320) determines the end of the TXOP of non-AP STA 1 (320), or thereafter, that non-AP STA 1 (320) is operating in a listening operation on the main channel again, and can transmit an ICF to non-AP STA 1 (320) to perform frame exchange on the main channel.

[0156] For example, in the operations described above, the DPS operation may be replaced with the EMLSR operation. Alternatively, the EMLSR operation may be used simultaneously with the DPS and DSO operations. Referring to FIG. 4, a non-AP STA 1 (320) may perform EMLSR and DPS operations. AP 1 (310) may want to switch the non-AP STA 1 (320) to a DSO channel. AP 1 (310) may transmit an ICF that switches the non-AP STA 1 (320) to a normal transmit / receive operation, HCM, and performs a switch to a DSO channel. Here, AP 1 (310) may set the length of the padding field of the ICF to a time equal to or longer than the sum of the EMLSR operation switching time, the DPS mode switching time, and the DSO channel switching time of the non-AP STA 1 (320). Alternatively, if EMLSR operation switching and DPS mode switching can be performed simultaneously, AP 1 (310) must set the length of the padding field of the ICF to a time equal to or longer than the sum of the “longer of the EMLSR operation switching time and the DPS mode switching time” of non-AP STA 1 (320) and the DSO channel switching time. Alternatively, AP 1 (310) must set the length of the padding field of the ICF to a time equal to or longer than the sum of at least one of the EMLSR operation switching time, the DPS mode switching time, and the DSO channel switching time of non-AP STA 1 (320).

[0157] After AP 1 (310) finishes exchanging frames with non-AP STA 1 (320), non-AP STA 1 (320) can determine that the TXOP has ended. The point at which AP 1 (310) can transmit frames to non-AP STA 1 (320) may be when non-AP STA 1 (320) is operating in LCM and listening operation on the main channel and can receive ICF frames. AP 1 (310) can transmit frames to non-AP STA 1 (320) at a time when the sum of the EMLSR operation switching time, the DPS mode switching time, and the DSO channel switching time has elapsed from the point at which non-AP STA 1 (320) determines that the TXOP has ended, or at a later time. Alternatively, AP 1 (310) may transmit a frame to non-AP STA 1 (320) at a time when a time equal to or greater than the sum of “the longer of the EMLSR operation transition time and the DPS mode transition time” and the DSO channel transition time has elapsed from the time when non-AP STA 1 (320) determines the end of the TXOP. Alternatively, AP 1 (310) may transmit a frame to non-AP STA 1 (320) at a time when a time equal to or greater than the sum of at least one of the EMLSR operation transition time, the DPS mode transition time, and the DSO channel transition time has elapsed from the time when non-AP STA 1 (320) determines the end of the TXOP has elapsed from a time when non-AP STA 1 (320) determines the end of the TXOP has elapsed or at a time when non-AP STA 1 (320) determines the end of the TXOP has elapsed.

[0158] FIG. 6 is a flowchart illustrating the operation of an STA in a wireless LAN to which the present disclosure applies. Referring to FIG. 6, in a wireless LAN system, a first STA may transmit an initial control frame (ICF) (S610). Here, the ICF may instruct at least one STA to perform a switching operation. Subsequently, the first STA receives an initial control response (ICR) from at least one STA (S620), and after receiving the ICR, the first STA may perform at least one of transmitting and receiving data to and from at least one STA (S630). Here, the switching operation instructed by the ICF may include at least one of a channel switching operation based on dynamic subchannel operation (DSO), a mode switching operation based on dynamic power saving (DPS), and a mode switching operation based on enhanced multi-link single radio (EMLSR). Additionally, the ICF may include a padding field, and the length of the padding field may be determined based on at least one switching operation by the ICF. Additionally, the padding field can be configured to correspond independently to each of at least one switching operation directed by the ICF.

[0159] If the ICF instructs the second STA among at least one STA to perform a channel switching operation based on DSO and a mode switching operation based on DPS, the channel switching operation based on DSO and the mode switching based on DPS may be performed in the second STA. The time required for the channel switching operation based on DSO and the time required for the mode switching operation based on DPS in the second STA are required individually, and the length of the padding field of the ICF may be determined based on the sum of the time required for the channel switching operation based on DSO and the time required for the mode switching operation based on DPS. Additionally, if the ICF instructs the second STA among at least one STA to perform a channel switching operation based on DSO and a mode switching operation based on DPS, the channel switching operation based on DSO and the mode switching based on DPS may be performed in the second STA. In the second STA, the time required for channel switching operation based on DSO and the time required for mode switching operation based on DPS are required simultaneously, so the length of the padding field of the ICF can be determined as the longer of the time required for channel switching operation based on DSO and the time required for mode switching operation based on DPS. Additionally, among at least one STA receiving the ICF, the second STA supports both DSO operation and DPS operation, and among at least one STA, the third STA supports DSO operation, the first STA can instruct the second STA to perform operation mode switching based on DPS through the ICF. The first STA can instruct the second STA through the ICF that the operation channel is maintained as the main channel, and the first STA can instruct the third STA through the ICF to perform operation channel switching based on DSO, thereby switching the operation channel of the third STA from the main channel to the DSO channel.Additionally, the length of the padding field of the ICF may be set to correspond to the longer of the time required for mode switching based on DPS in the second STA and the time required for channel switching based on DSO in the third STA, or the time required for mode switching based on DPS in the second STA and the time required for channel switching based on DSO in the third STA. Additionally, among at least one STA receiving the ICF, the second STA supports both DSO operation and DPS operation, and among at least one STA, the third STA supports DSO operation. In this case, the first STA may instruct the second STA to switch the operation channel of the second STA from the main channel to the DSO channel by instructing the second STA to switch the operation channel based on DSO through the ICF. The first STA may instruct the second STA through the ICF that the operation mode based on DPS is maintained, and the first STA may instruct the third STA through the ICF that the operation channel of the third STA is maintained as the main channel. Additionally, the length of the padding field of the ICF can be set to correspond to the time required for channel switching based on DSO in the second STA. Additionally, if among at least one STA receiving the ICF, the second STA supports both DSO operation and DPS operation, and among at least one STA, the third STA supports DSO operation, the first STA can instruct the second STA via the ICF to maintain the DPS-based operation mode and the DSO-based operation channel, and instruct the third STA via the ICF to switch the DSO-based operation channel, thereby switching the operation channel of the third STA from the main channel to the DSO channel. The length of the padding field of the ICF can be set to correspond to the time required for channel switching based on DSO in the third STA.Additionally, among at least one STA receiving the ICF, the second STA supports both DSO operation and DPS operation, and among at least one STA, the third STA supports DSO operation. In this case, the first STA may instruct the second STA via the ICF to switch the operation mode based on DPS and switch the operation channel based on DSO, and the first STA may instruct the third STA via the ICF that the operation channel of the third STA is maintained as the main channel. Additionally, the length of the padding field of the ICF may be set to correspond to the longer of the time required for mode switching based on DPS in the second STA and the time required for channel switching based on DSO in the second STA, or the time required for mode switching based on DPS in the second STA and the time required for channel switching based on DSO in the second STA.

[0160] Additionally, the DPS operation may include a lower capability mode (LCM) in which at least one of the operation bandwidth, the number of operation space streams, and the modulation coding scheme (MCS) is limited, or only the reception of an initial control frame is possible, and a higher capability mode (HCM) in which normal transmit and receive operations are possible. The DSO operation may be an operation that switches the operation channel from the main channel to the DSO channel to perform transmit and receive along with the main channel transmission. Additionally, the EMLSR operation mode may include a listening operation mode in which only the reception of an initial control frame is possible over multiple links and a normal transmit and receive mode. As an example, the first STA may be a non-AP STA or an AP STA.

[0161] 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.

[0162]

[0163]

[0164]

[0165] 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, The step of the first STA transmitting an initial control frame (ICF), wherein the ICF instructs at least one STA to perform a switching operation; The step of the first STA receiving an initial control response (ICR) from at least one STA; and A method of operation comprising the step of performing at least one of transmitting and receiving data to at least one STA after the first STA receives the ICR.

2. In Paragraph 1, A method of operation in which the switching operation indicated by the above ICF includes at least one of a channel switching operation based on DSO (dynamic subchannel operation), a mode switching operation based on DPS (dynamic power saving), and a mode switching operation based on EMLSR (enhanced multi-link single radio).

3. In Paragraph 2, A method of operation in which the above ICF includes a padding field, and the length of the padding field is determined based on at least one switching operation by the above ICF.

4. In Paragraph 3, A method of operation in which the padding field is set to correspond independently to each of the at least one switching operation indicated by the ICF.

5. In Paragraph 4, A method of operation in which, when the ICF instructs the second STA among the at least one STA to perform a channel switching operation based on the DSO and a mode switching operation based on the DPS, the channel switching operation based on the DSO and the mode switching based on the DPS are performed in the second STA, wherein the time required for the channel switching operation based on the DSO and the time required for the mode switching operation based on the DPS in the second STA are required individually, and the length of the padding field of the ICF is determined based on the sum of the time required for the channel switching operation based on the DSO and the time required for the mode switching operation based on the DPS.

6. In Paragraph 3, A method of operation in which, when the second STA among the at least one STA is instructed by the above ICF to perform a channel switching operation based on the DSO and a mode switching operation based on the DPS, the channel switching operation based on the DSO and the mode switching based on the DPS are performed in the second STA, wherein the time required for the channel switching operation based on the DSO and the time required for the mode switching operation based on the DPS in the second STA are required simultaneously, and the length of the padding field of the above ICF is determined as the longer of the time required for the channel switching operation based on the DSO and the time required for the mode switching operation based on the DPS.

7. In Paragraph 3, A method of operation in which, among the at least one STA receiving the ICF, the second STA supports both DSO operation and DPS operation, and among the at least one STA, the third STA supports DSO operation, wherein the first STA instructs the second STA to switch an operation mode based on the DPS through the ICF, the first STA instructs the second STA through the ICF that the operation channel is maintained as the main channel, and the first STA instructs the third STA through the ICF to switch an operation channel based on the DSO, thereby switching the operation channel of the third STA from the main channel to the DSO channel.

8. In Paragraph 7, A method of operation in which the length of the padding field of the ICF is set to correspond to the longer of the time required for mode switching based on the DPS in the second STA and the time required for channel switching based on the DSO in the third STA, or the time required for mode switching based on the DPS in the second STA and the time required for channel switching based on the DSO in the third STA.

9. In Paragraph 3, A method of operation in which, among the at least one STA receiving the ICF, the second STA supports both DSO operation and DPS operation, and among the at least one STA, the third STA supports DSO operation, wherein the first STA instructs the second STA via the ICF to switch the operation channel of the second STA from the main channel to the DSO channel, and the first STA instructs the second STA via the ICF that the operation mode based on the DPS is maintained, and the first STA instructs the third STA via the ICF that the operation channel of the third STA is maintained as the main channel.

10. In Paragraph 9, A method of operation in which the length of the padding field of the above ICF is set to correspond to the time required for channel switching based on the DSO in the second STA.

11. In Paragraph 3, A method of operation in which, among the at least one STA receiving the ICF, the second STA supports both DSO operation and DPS operation, and among the at least one STA, the third STA supports DSO operation, wherein the first STA instructs the second STA via the ICF to maintain an operation mode based on the DPS and maintain an operation channel based on the DSO, and instructs the third STA via the ICF to switch the operation channel based on the DSO, thereby switching the operation channel of the third STA from the main channel to the DSO channel.

12. In Paragraph 11, A method of operation in which the length of the padding field of the above ICF is set to correspond to the time required for channel switching based on the DSO of the above third STA.

13. In Paragraph 3, A method of operation in which, among the at least one STA receiving the ICF, the second STA supports both DSO operation and DPS operation, and among the at least one STA, the third STA supports DSO operation, the first STA instructs the second STA via the ICF to switch an operation mode based on the DPS and to switch an operation channel based on the DSO, and the first STA instructs the third STA via the ICF that the operation channel of the third STA is maintained as the main channel.

14. In Paragraph 13, A method of operation in which the length of the padding field of the ICF is set to correspond to the longer of the time required for mode switching based on the DPS in the second STA and the time required for channel switching based on the DSO in the second STA, or the time required for mode switching based on the DPS in the second STA and the time required for channel switching based on the DSO in the second STA.

15. In Paragraph 2, The above DPS operation is a method of operation comprising a lower capability mode (LCM) in which at least one of the operation bandwidth, the number of operation space streams, and the modulation coding scheme (MCS) is limited or only the reception of an initial control frame is possible, and a higher capability mode (HCM) in which general transmission and reception operations are possible.

16. In Paragraph 2, The above DSO operation is an operation method in which the operation channel is switched from the main channel to the DSO channel to perform transmission and reception together with the main channel transmission.

17. In Paragraph 2, The above EMLSR operation mode includes a listening operation mode capable of receiving only the initial control frame in multiple links and a normal transmission / reception mode, an operation method.

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

19. 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: Transmit an initial control frame (ICF), wherein the ICF instructs at least one other STA to perform a switching operation, and Receiving an initial control response (ICR) from at least one other STA, and A STA that performs at least one of transmitting and receiving data to at least one STA after receiving the above ICR.

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