Method and device for operating sub-channel in low-latency communication period of wireless LAN

Abstract

The present invention may: configure a low-latency communication period in a wireless LAN system, wherein the low-latency communication period is a communication period in which only a low-latency communication period member STA can transmit and receive a frame; detect transmission in an OBSS before a start point of the low-latency communication period; switch an operation channel from a primary channel to an NPCA channel on the basis of a time period corresponding to the transmission in the OBSS; and after the operation channel is switched to the NPCA channel and if an NPCA operation period operating in the NPCA channel overlaps the low-latency communication period, start the low-latency communication period in the NPCA channel.

Description

Method and device for operating a side channel in a low-latency communication section of a wireless LAN

[0001] The present disclosure relates to a method and apparatus for side-channel operation in a low-latency communication section of a wireless local area network (WLAN). Specifically, it relates to a method for performing non-primary channel access (NPCA) operation in a low-latency communication section of a wireless LAN.

[0002]

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

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

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

[0006] Here, when the section where NPCA operation is performed overlaps with the low-latency communication section, a method to effectively perform low-latency communication operation may be required, and this is described below.

[0007] 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.

[0008]

[0009] The present disclosure relates to a method for operating a subchannel in a low-latency communication section of a wireless LAN.

[0010] The present disclosure relates to a method for efficiently performing low-latency communication when NPCA operation and low-latency communication sections overlap in a wireless LAN.

[0011] The present disclosure relates to a method for efficiently performing low-latency communication in a low-latency communication section even when a side-channel access operation is performed in a wireless LAN.

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

[0013]

[0014] According to one embodiment of the present specification, in a method of operation of a station (STA) in a wireless LAN system, the STA may include the step of setting a low-latency communication section, wherein the low-latency communication section is a communication section in which only the low-latency communication section member STA can transmit and receive frames, the STA detects a transmission within an overlapping basic service set (OBSS) before the start point of the low-latency communication section, and switches the operating channel from a primary channel to a non-primary channel access (NPCA) channel based on a time section corresponding to the transmission within the OBSS, and, if the STA switches the operating channel to the NPCA channel and the low-latency communication section overlaps with the NPCA operating section operating in the NPCA channel, the method may include the step of starting the low-latency communication section in the NPCA channel.

[0015] In addition, 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 at least one processor, wherein the specific operation is: setting a low-latency communication interval, wherein the low-latency communication interval is a communication interval in which only the low-latency communication interval member STA can transmit and receive frames, detecting a transmission within an overlapping basic service set (OBSS) prior to the start point of the low-latency communication interval, switching the operating channel from a primary channel to a non-primary channel access (NPCA) channel based on a time interval corresponding to the transmission within the OBSS, and, if the NPCA operating interval operating in the NPCA channel overlaps with the low-latency communication interval after switching the operating channel to the NPCA channel, the low-latency communication interval can be started in the NPCA channel.

[0016] In addition, according to one embodiment of the present specification, in a method of operation of a station (STA) in a wireless LAN system, the STA may include the step of setting a low-latency communication section, wherein the low-latency communication section is a communication section in which only the low-latency communication section member STA can transmit and receive frames, the STA detects a transmission within an overlapping basic service set (OBSS) before the start point of the low-latency communication section, and switches the operating channel from the main channel to a non-primary channel access (NPCA) channel based on a time section corresponding to the transmission within the OBSS, and if the STA switches the operating channel to the NPCA channel and the low-latency communication section overlaps with the NPCA operating section operating in the NPCA channel, the STA may include the step of starting the low-latency communication section when the STA switches the operating channel from the NPCA channel to the main channel after the NPCA operating section ends.

[0017] In addition, 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: setting a low-latency communication interval, wherein the low-latency communication interval is a communication interval in which only the low-latency communication interval member STA can transmit and receive frames, detecting a transmission within an overlapping basic service set (OBSS) prior to the start point of the low-latency communication interval, switching the operating channel from the main channel to a non-primary channel access (NPCA) channel based on a time interval corresponding to the transmission within the OBSS, and, if the NPCA operating interval operating in the NPCA channel overlaps with the low-latency communication interval after switching the operating channel to the NPCA channel, the low-latency communication interval can be started by switching the operating channel from the NPCA channel to the main channel after the NPCA operating interval ends.

[0018] In addition, the following points may apply in common.

[0019] According to one embodiment of the present specification, the acquisition of a transmission opportunity (TXOP) based on channel access in an NPCA channel may be granted without restriction regardless of the STA type.

[0020] In addition, according to one embodiment of the present specification, the STA is a non-AP STA connected to an access point (AP), and when the STA sets a TXOP in an NPCA channel, the STA can set the TXOP so that the TXOP is terminated before the start of a low-latency communication period in the NPCA channel.

[0021] In addition, according to one embodiment of the present specification, the STA is a non-AP STA connected to an AP, and when the STA sets a TXOP in an NPCA channel, the STA can terminate the TXOP by transmitting a CF (contention free)-end frame before the start of the low-latency communication period.

[0022] Additionally, according to one embodiment of the present specification, in an NPCA channel, a STA is granted to acquire a transmission opportunity (TXOP) based on channel access, and at least one STA connected to the STA may not be granted to acquire a TXOP based on channel access in the NPCA channel.

[0023] In addition, according to one embodiment of the present specification, when a STA sets a TXOP that performs frame exchange with a STA other than a member STA of the low-latency communication section in an NPCA channel, the STA may set the TXOP so that the TXOP is terminated before the start of the low-latency communication section in the NPCA channel.

[0024] In addition, according to one embodiment of the present specification, if a TXOP in which a STA performs frame exchange with another STA that is not a member STA of the low-latency communication section in an NPCA channel is set after the start time of the low-latency communication section, the STA may terminate the TXOP by transmitting a CF (contention free)-end frame before the start of the low-latency communication section.

[0025] In addition, according to one embodiment of the present specification, when a STA sets a TXOP that performs frame exchange with a STA that is a member STA of a low-latency communication section in an NPCA channel, the STA may set the TXOP regardless of whether a low-latency communication section starts in the NPCA channel.

[0026] In addition, according to one embodiment of the present specification, the STA may be an AP STA.

[0027] In addition, according to one embodiment of the present specification, when the time interval corresponding to transmission within the OBSS ends, the STA can switch the operating channel from the NPCA channel to the main channel.

[0028] In addition, according to one embodiment of the present specification, a TXOP set in a low-latency communication interval may be terminated before the switching delay from the time when the STA switches from the NPCA channel to the main channel.

[0029] Additionally, according to one embodiment of the present specification, when a low-latency communication interval is maintained after the STA switches the operating channel from the NPAC channel to the main channel, only the STA and the low-latency communication interval member STA connected to the STA may be granted to acquire a TXOP based on channel access while the low-latency communication interval is maintained after switching the operating channel to the main channel.

[0030] Additionally, according to one embodiment of the present specification, when a low-latency communication interval is maintained after the STA switches the operating channel from the NPCA channel to the main channel, the STA is granted to acquire a TXOP based on channel access while the low-latency communication interval is maintained after switching the operating channel to the main channel, and the low-latency communication interval member STA connected to the STA may not be granted to acquire the TXOP based on channel access.

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

[0032] Additionally, according to one embodiment of the present specification, the low-latency communication period may be an R-TWT (restricted target wake time) SP (service period).

[0033]

[0034] According to the present disclosure, a method for operating a subchannel in a low-latency communication section of a wireless LAN can be provided.

[0035] According to the present disclosure, a method for efficiently performing low-latency communication can be provided when NPCA operation and low-latency communication sections overlap in a wireless LAN.

[0036] According to the present disclosure, a method can be provided to efficiently perform low-latency communication in a low-latency communication section even when a side-channel access operation is performed in a wireless LAN.

[0037] 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.

[0038]

[0039] FIG. 1 is a diagram showing a communication node within a wireless LAN system to which the present disclosure applies.

[0040] FIG. 2 is a drawing showing a wireless LAN system to which the present disclosure is applied.

[0041] Figures 3a and 3b are diagrams illustrating the operation method of the low-latency communication section during wireless LAN sub-channel access operation.

[0042] Figures 4a and 4b are diagrams illustrating the operation method of the low-latency communication section during wireless LAN sub-channel access operation.

[0043] FIGS. 5A and 5B are drawings illustrating a wireless LAN low-latency communication section protection method applied to the present disclosure.

[0044] FIG. 6 is a diagram showing a low-latency communication section operation method during wireless LAN subchannel access operation applied to the present disclosure.

[0045] FIG. 7 is a flowchart illustrating the operation of an STA in a wireless LAN to which the present disclosure applies.

[0046] FIG. 8 is a flowchart showing the operation of a STA in a wireless LAN to which the present disclosure applies.

[0047]

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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."

[0055] 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.

[0056] 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).

[0057] 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).

[0058] 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).

[0059] 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.

[0060] 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.

[0061] The following describes a method for performing low-latency communication in the low-latency communication section when side-channel access operations and the low-latency communication section overlap in a wireless LAN. As described above, low-latency communication performance in a wireless LAN network can be improved.

[0062] Consider a case where AP 1, STA 1, and STA 2 operate in a wireless LAN network. AP 1, STA 1, and STA 2 may have a pre-configured primary channel and an NPCA primary channel. The primary channel may be a channel that includes the primary 20MHz channel of the basic service set (BSS) configured by AP 1, STA 1, and STA 2. The NPCA primary channel may be a predetermined channel that does not include the primary 20MHz channel in the BSS configured by AP 1, STA 1, and STA 2. If the primary channel is occupied by a different BSS, AP 1, STA 1, and STA 2 may switch the operating channel to the NPCA primary channel to operate. For example, the other BSS may be the BSS configured by AP X and STA X, and the other BSS may be an overlapping BSS. That is, when the primary channel is occupied by AP X or STA X, at least one of AP 1, STA 1, and STA 2 may operate on the NPCA primary channel. At least one of AP 1, STA 1, and STA 2 may perform channel access on the NPCA primary channel and switch the channel to the NPCA primary 20 MHz channel to operate. Alternatively, at least one of AP 1, STA 1, and STA 2 may perform channel sensing for a PIFS (priority interframe space) time from before the completion of channel access to extend the bandwidth to an idle channel and perform frame transmission. Based on the above, the operation of performing frame transmission may be an NPCA operation. Here, the channel including the NPCA primary channel used for transmission may be an NPCH (non-primary channel), but is not limited to that name.The NPCA operation described above can be applied in FIGS. 3a to 6 below, and depending on each figure, it may be possible to perform an operation different from that described above.

[0063] FIGS. 3a and 3b are drawings illustrating a low-latency communication section operation method during wireless LAN subchannel access operation applied to the present disclosure.

[0064] Referring to FIGS. 3a and 3b, an AP (e.g., AP 1) can transmit and receive frames without restrictions on the NPCA main channel. STAs (e.g., STA 1 and STA 2) can also transmit uplink frames and receive downlink frames without restrictions on the NPCA main channel. The ability of an STA to transmit uplink frames and receive downlink frames without restrictions on the NPCA main channel may be made possible through capability negotiation between the STA and the AP. Specifically, during the negotiation process between the STA and the AP, it may be supported for the STA to transmit uplink frames and receive downlink frames without restrictions on the NPCA main channel. Additionally, during the negotiation process between the STA and the AP, the AP may allow the STA to transmit uplink frames and receive downlink frames without restrictions on the NPCA main channel, thereby enabling the transmission of uplink frames and the reception of downlink frames without restrictions on the NPCA main channel.

[0065] Referring to FIG. 3a, AP 1 (310) can set a low-latency communication period. The low-latency communication period may be an R-TWT (restricted target wake time) SP (service period). When a low-latency communication period is set, STAs that are not members of the low-latency communication period must terminate frame transmission (specifically, a TXOP (transmit opportunity), which is a time period in which multiple frames are transmitted and response frames for the transmitted frames are exchanged) before the start time of the low-latency communication period. AP 1 (310) may include a TWT element in the beacon frame and the probe response frame to set the low-latency communication period. The TWT element indicates the start time of the R-TWT SP, which is the low-latency communication period, and may instruct STAs requiring low-latency communication to participate as members of the low-latency communication period. For example, non-AP STA 1 (320) may not be a member of the R-TWT SP, which is a low-latency communication section, and non-AP STA 2 (330) may become a member of the R-TWT SP by sending a TWT setup frame to AP 1 (310), but this is for convenience of explanation only and is not limited thereto.

[0066] The communication period of the OBSS (i.e., the TXOP of the OBSS) can be detected before the low-latency communication period begins. The communication period of the OBSS may overlap with all or part of the low-latency communication period. AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330) may operate in the NPCH during the TXOP period of the OBSS. Uplink transmission via channel access by non-AP STA 1 (320) and non-AP STA 2 (330) may be allowed in the NPCH. Thus, non-AP STA 1 (320) may perform channel access operations (e.g., an enhanced distributed channel access (EDCA) backoff procedure and an EDCA TXOP acquisition procedure) in the NPCH, and if the channel access operation is successful, acquire a TXOP, which is a time period during which multiple frames can be transmitted. Here, the operation requiring communication to be terminated before the start of the low-latency communication period may be applied in the same way in the NPCH. That is, non-AP STA 1 (320) can set the TXOP so that the TXOP is terminated before the start of the R-TWT SP. Additionally, if the TXOP is set to a length that encroaches on the R-TWT SP, non-AP STA 1 (320) can terminate frame transmission before the start of the R-TWT SP and transmit a CF (contention free)-end frame. Through this, in response to the TXOP of non-AP STA 1 (320), other STAs (AP 1, non-AP STA 2, and wireless LAN communication nodes capable of receiving frames from non-AP STA 1) can terminate the NAV (network allocation vector), which is the time period during which the medium is detected to be busy. That is, non-AP STA 1 (320), which is not a member of the low-latency communication section, may have to terminate frame transmission before the low-latency communication section indicated by AP 1 (310) on the main channel begins in the NPCH.

[0067] Referring to FIG. 3a, based on the above description, a low-latency communication period R-TWT SP can be initiated, and the low-latency communication period and the NPCA operation period (i.e., the period in which AP 1, non-AP STA 1, and non-AP STA 2 operate in the NPCH) can overlap. Here, non-AP STA 2 (330), a member of the R-TWT SP, can perform frame transmission to AP 1 (310) if the channel access operation is successful. Non-AP STA 2 (330) can terminate frame transmission before the TXOP end time of the OBSS and before the switching delay time, which is the time for non-AP STA 2 (330) to switch the operating channel back to the main channel in the NPCH. As another example, if AP 1 (310), to which non-AP STA 2 (330) transmits a frame, has a longer switching delay than non-AP STA 2 (330), non-AP STA 2 (330) may terminate frame transmission before the switching delay time, which is the time for AP 1 (310) to switch the operating channel back from the NPCH to the main channel before the TXOP of OBSS ends.

[0068] Referring to FIG. 3b, based on the above description, a low-latency communication period, the R-TWT SP, can be initiated, and the low-latency communication period and the NPCA operation period (i.e., the period in which AP 1, non-AP STA 1, and non-AP STA 2 operate in the NPCH) can overlap. AP 1 (310) can perform frame transmission when the channel access operation in the R-TWT SP is successful. Here, AP 1 (310) can transmit the frame to a member STA of the R-TWT SP (e.g., non-AP STA 2). For example, as described above, non-AP STA 2 (330) may be a member STA of the R-TWT SP. AP 1 (310) can terminate frame transmission before the OBSS TXOP ends and before the switching delay time, which is the time for AP 1 (310) to switch the operating channel back to the main channel in the NPCH. Alternatively, if the non-AP STA 2 (330) to which AP 1 (310) transmits the frame has a longer switching delay than AP 1 (310), AP 1 (310) may terminate the frame transmission before the non-AP STA 2 (330) switches the operating channel back from the NPCH to the main channel before the end of the OBSS TXOP, which is the time for the non-AP STA 2 (330) to switch the operating channel back to the main channel.

[0069] As another example, frame transmission of both non-AP STA 2 (330) and AP 1 (310) may be performed within the R-TWT SP differently from what was described above. Specifically, referring to FIGS. 3a and 3b, AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330) may be operating on the main channel again at the time the OBSS TXOP ends. The R-TWT SP may not have ended at the time when AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330) are operating on the main channel again. In the above case, a transmission prohibition period with a specific time length may be set for non-AP STA 1 (320), which is not a member STA of the R-TWT SP, and frame transmission may be restricted during that time. The aforementioned transmission prohibition period may be a pre-agreed period, and the member STAs of the R-TWT SP may perform the operations described below during that period. For example, non-AP STA 1 (320) may be prohibited from transmitting frames for 1 TU (time unit) when it operates on the main channel again. Here, 1 TU may be 1024 us. That is, even if non-AP STA 1 (320) successfully accesses the channel, the EDCAF (EDCA function) of non-AP STA 1 (320) may perform backoff again during the transmission prohibition period. Alternatively, the EDCAF (EDCA function) of non-AP STA 1 (320) may do nothing during the transmission prohibition period.

[0070] Alternatively, non-AP STA 1 (320) may detect the medium in an occupied state by setting NAV during the period corresponding to the transmission prohibition period. Alternatively, non-AP STA 1 (320) may stop EDCA operation during the transmission prohibition period. Non-AP STA 2 (330), a member of the R-TWT SP, may be allowed channel access operation and may be able to transmit uplink frames to AP 1 (310). Additionally, AP 1 (310) may also be allowed channel access operation and may be allowed to transmit downlink frames to non-AP STA 2 (330), a member STA of the R-TWT SP.

[0071] As another example, when AP 1 (310), non-AP STA 1 (320) and non-AP STA 2 (330) are operating on the main channel again, if the R-TWT SP has not been terminated, a transmission prohibition period of a specific time length may be set for the other STAs excluding AP 1 (310). In the above case, AP 1 (310) may transmit a downlink frame to non-AP STA 2 (330). Alternatively, AP 1 (310) may transmit a trigger frame to non-AP STA 2 (330), and based on this, non-AP STA 2 (330) may transmit an uplink frame to AP 1 (310).

[0072] Meanwhile, in a situation where the NPCA operation period and the low-latency communication period overlap, FIG. 3a may be an uplink transmission operation method of a non-AP STA, and FIG. 3b may be a downlink transmission operation method of an AP. However, in a situation where the NPCA operation period and the low-latency communication period overlap, it may not be limited to performing only one of the uplink frame transmission and downlink frame transmission. That is, the downlink transmission and uplink transmission operations described above can be applied in the same way even when both are performed in a situation where the NPCA operation period and the low-latency communication period overlap.

[0073] FIGS. 4a and 4b are drawings illustrating a low-latency communication section operation method during wireless LAN sub-channel access operation applied to the present disclosure.

[0074] Referring to FIGS. 4a and 4b, in the NPCA main channel, an AP (e.g., AP 1) can transmit and receive frames without restriction. In the NPCA main channel, STAs (e.g., non-AP STA 1 and non-AP STA 2) may be restricted from transmitting uplink frames. In order for non-AP STA 1 (320) and non-AP STA 2 (330) to perform uplink transmission, they may need to receive a trigger frame from AP 1 (310) to be allocated uplink resources. Additionally, AP 1 (310) may set a low-latency communication period. The low-latency communication period may be a restricted target wake time (R-TWT) service period (SP). When a low-latency communication period is set, STAs that are not members of the low-latency communication period must terminate frame transmission (specifically, a transmit opportunity (TXOP) which is a time period during which multiple frames are transmitted and response frames for the transmitted frames are exchanged) before the start of the low-latency communication period. AP 1 (310) may include a TWT element in the beacon frame and probe response frame to set up a low-latency communication period. The TWT element indicates the start time of the R-TWT SP, which is the low-latency communication period, and may instruct STAs requiring low-latency communication to participate as members of the low-latency communication period. For example, non-AP STA 1 (320) may not be a member of the R-TWT SP, which is the low-latency communication period, and non-AP STA 2 (330) may become a member of the R-TWT SP by sending a TWT setup frame to AP 1 (310), but this is for convenience of explanation only and is not limited thereto.

[0075] Referring to FIG. 4a, the communication period of the OBSS (i.e., the TXOP of the OBSS) can be detected before the low-latency communication period begins. The communication period of the OBSS may overlap with all or part of the low-latency communication period. AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330) may operate in the NPCH during the TXOP period of the OBSS. Here, uplink transmission via channel access by non-AP STA 1 (320) and non-AP STA 2 (330) is not allowed in the NPCH. If AP 1 (310) performs a channel access operation (e.g., an enhanced distributed channel access (EDCA) backoff procedure and an EDCA TXOP acquisition procedure) in the NPCH and the channel access operation is successful, it can acquire a TXOP, which is a time period during which multiple frames can be transmitted. The frame transmitted by AP 1 (310) may be a trigger frame or a downlink frame transmitted to a non-AP STA 1 (320). Here, the same operation of terminating communication before the start of the low-latency communication period may be applied in the NPCH. That is, if the frame transmission of AP 1 (310) is performed to a STA that is not a member STA of the R-TWT SP, AP 1 (310) may set the TXOP corresponding to the frame transmission to a STA that is not a member STA of the R-TWT SP to terminate before the start of the R-TWT SP. Alternatively, if the TXOP is set to a length that encroaches on the R-TWT SP, AP 1 (310) may transmit a CF (contention free)-end frame instructing to terminate the frame transmission before the start of the R-TWT SP and to release the NAV set based on the frame transmitted within the TXOP of AP 1 (310).Through this, the network allocation vector (NAV), which is the time interval during which other STAs (non-AP STA 1 (320), non-AP STA 2 (330), and wireless LAN communication nodes capable of receiving frames from AP 1 (310)) detect the medium as being busy in response to the TXOP of AP 1 (310), can be terminated.

[0076] As another example, AP 1 (310) may not transmit a separate CF-End frame to initialize the NAV even if the TXOP it acquired overlaps with the R-TWT SP. That is, since transmissions by non-AP STA 1 (320) and non-AP STA 2 (330) are not allowed in the NPCH and only AP 1 (310) can perform channel access, AP 1 (310) may not initialize the NAV set by its TXOP. Therefore, AP 1 (310) may not transmit the aforementioned CF-End frame, but may have to stop exchanging frames before the start of the R-TWT SP.

[0077] The R-TWT SP starts in the NPCH, and AP 1 (310) can perform frame transmission when the channel access operation in the R-TWT SP is successful. AP 1 (310) can transmit the frame to a member STA of the R-TWT SP. For example, as described above, non-AP STA 2 (330) may be a member STA of the R-TWT SP, but this is for convenience of explanation only and is not limited thereto. AP 1 (310) can terminate frame transmission before the TXOP of the OBSS ends, and before the switching delay time, which is the time for AP 1 (310) to switch the operating channel back to the main channel from the NPCH. Alternatively, if the non-AP STA 2 (330), to which AP 1 (310) transmits the frame, has a longer switching delay than AP 1 (310), AP 1 (310) may terminate the frame transmission before the time of the OBSS TXOP termination, which is the time for non-AP STA 2 (330) to switch the operating channel back from the NPCH to the main channel. When AP 1 (310) transmits a trigger frame to non-AP STA 2 (330), AP 1 (310) may receive an uplink frame from non-AP STA 2 (330) at the R-TWT SP, and AP 1 (310) may transmit a downlink frame from the R-TWT SP to non-AP STA 2 (330), which is a member of the R-TWT SP.

[0078] Referring to FIG. 4b, the communication period of the OBSS (i.e., the TXOP of the OBSS) can be detected before the low-latency communication period begins. The communication period of the OBSS may overlap with all or part of the low-latency communication period. AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330) may operate in the NPCH during the TXOP period of the OBSS. Uplink transmission via channel access by non-AP STA 1 (320) and non-AP STA 2 (330) is not allowed in the NPCH. If AP 1 (310) performs a channel access operation (e.g., an enhanced distributed channel access (EDCA) backoff procedure and an EDCA TXOP acquisition procedure) in the NPCH and the channel access operation is successful, it may acquire a TXOP, which is a time period during which multiple frames can be transmitted.

[0079] Here, if the operating intervals of the R-TWT SP and NPCH overlap, AP 1 (310) is allowed to transmit frames only to the member STA of the R-TWT SP. When AP 1 (310) transmits a frame to the R-TWT SP member STA, since AP 1 (310) is transmitting a frame to the R-TWT SP member STA, it is not necessary to terminate the TXOP before the start of the R-TWT SP. Specifically, AP 1 (310) can perform frame transmission if the channel access operation is successful. Here, AP 1 (310) can transmit the frame to the member STA of the R-TWT SP. That is, AP 1 (310) can perform frame transmission to non-AP STA 2 (330), which is a member of the R-TWT SP. AP 1 (310) may terminate frame transmission before the OBSS TXOP ends and before the switching delay time, which is the time for AP 1 (310) to switch the operating channel back from the NPCH to the main channel. Alternatively, if the non-AP STA 2 (330) to which AP 1 (310) transmits the frame has a longer switching delay than AP 1 (310), AP 1 (310) may terminate frame transmission before the OBSS TXOP ends and before the switching delay time, which is the time for non-AP STA 2 (330) to switch the operating channel back from the NPCH to the main channel. When AP 1 (310) sends a trigger frame to non-AP STA 2 (330), AP 1 (310) can receive an uplink frame from non-AP STA 2 (330) at the R-TWT SP, and AP 1 (310) can send a downlink frame from the R-TWT SP to non-AP STA 2 (330), which is a member of the R-TWT SP.

[0080] Referring to FIGS. 4a and 4b, at the time the OBSS TXOP ends, AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330) may operate on the main channel again. However, the R-TWT SP may not have ended at the time when AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330) operate on the main channel again. In the above case, non-AP STA 1 (320), which is not a member STA of the R-TWT SP, may be subject to a transmission prohibition period of a specific time length, and frame transmission may be restricted during that time. For example, non-AP STA 1 (320) may be prohibited from transmitting frames for 1 TU (time unit) at the time it operates on the main channel again. Here, 1 TU may be 1024 us. Even if non-AP STA 1 (320) succeeds in accessing the channel, the EDCAF (EDCA function) of non-AP STA 1 (320) may perform backoff again during the transmission prohibition period. Alternatively, the EDCAF (EDCA function) of non-AP STA 1 (320) may do nothing during the transmission prohibition period.

[0081] Alternatively, non-AP STA 1 (320) may detect the medium in an occupied state by setting NAV during the period corresponding to the transmission prohibition period. Alternatively, non-AP STA 1 (320) may stop EDCA operation during the transmission prohibition period. Non-AP STA 2 (330), a member of the R-TWT SP, may be allowed channel access operation and may be able to transmit uplink frames to AP 1 (310). Additionally, AP 1 (310) may also be allowed channel access operation and may be allowed to transmit downlink frames to non-AP STA 2 (330), a member STA of the R-TWT SP.

[0082] As another example, when AP 1 (310), non-AP STA 1 (320) and non-AP STA 2 (330) are operating on the main channel again, if the R-TWT SP has not been terminated, a transmission prohibition period of a specific time length may be set for the other STAs excluding AP 1 (310). In the above case, AP 1 (310) may transmit a downlink frame to non-AP STA 2 (330). Alternatively, AP 1 (310) may transmit a trigger frame to non-AP STA 2 (330), and non-AP STA 2 (330) may transmit an uplink frame to AP 1 (310) based on the trigger frame.

[0083] AP 1 (310) can perform a process to induce the transmission of a buffer status report and the NPCA operation status of terminals within the BSS when the NPCA operation begins. Specifically, the process described above can be performed by transmitting a BSRP (buffer status report poll) trigger frame within the TXOP of AP 1 (310). When the NPCA operation period overlaps with the R-TWT SP, AP can induce the transmission of a Trigger-Based PPDU (TB PPDU) of one or more specific STAs included as members of the R-TWT SP when transmitting the BSRP trigger frame. AP 1 (310) can determine whether to perform an R-TWT SP protection operation based on whether the member STAs respond. For example, if one or more STAs among the members of the R-TWT SP that overlap with the BSRP trigger frame respond, AP 1 (310) can perform an R-TWT SP protection operation. Therefore, AP 1 (310) may not set a subsequent TXOP to a length that exceeds the start time of the R-TWT SP. For example, if the TXOP in which the BSRP trigger frame is transmitted exceeds the start time of the R-TWT SP, AP 1 (310) may transmit a CF-end frame before the start time of the R-TWT SP to release the NAV of the STAs within the BSS. Alternatively, AP 1 (310) may not transmit a separate CF-End frame to release the NAV because communication is possible within the R-TWT SP. AP 1 (310) may not transmit the aforementioned CF-End frame, but may have to stop exchanging frames before the start time of the R-TWT SP.On the other hand, if the transmission of TB PPDU by all member STAs of the R-TWT SP that overlaps with the BSRP trigger frame is induced but none of the member STAs respond, AP 1 (310) may not perform the R-TWT SP protection operation. Therefore, AP 1 (310) may set the TXOP to a length that extends beyond the R-TWT SP start time in subsequent TXOPs. If the TXOP containing the transmission of the BSRP trigger frame extends beyond the R-TWT SP start time, the TXOP may be retained.

[0084] FIGS. 5A and 5B are drawings illustrating a wireless LAN low-latency communication section protection method applied to the present disclosure.

[0085] Consider a case where AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330) are operating in a wireless LAN network. AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330) may have a pre-configured primary channel and an NPCA primary channel. The primary channel may be a channel that includes the primary 20 MHz channel of the basic service set (BSS) configured by AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330). The NPCA primary channel may be a predetermined channel that does not include the primary 20 MHz channel in the BSS configured by AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330). AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330) can operate by switching the operating channel to the NPCA main channel when the main channel is occupied by a different BSS. For example, the other BSS may be a BSS configured by AP X and STA X, and the other BSS may be an OBSS (overlapping BSS). That is, when the main channel is occupied by AP X or STA X, AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330) cannot detect the main channel as occupied and cannot perform frame transmission.

[0086] Here, AP 1 (310) can set a low-latency communication period. The low-latency communication period may be a restricted target wake time (R-TWT) service period (SP). When a low-latency communication period is set, STAs that are not members of the low-latency communication period must terminate frame transmission (specifically, a transmit opportunity (TXOP) which is a time period during which multiple frames are transmitted and response frames for the transmitted frames are exchanged) before the start time of the low-latency communication period. AP 1 (310) may include a TWT element in the beacon frame and the probe response frame to set the low-latency communication period. The TWT element indicates the start time of the R-TWT SP, which is the low-latency communication period, and may instruct STAs requiring low-latency communication to participate as members of the low-latency communication period. For example, non-AP STA 1 (320) may not be a member of the R-TWT SP, which is a low-latency communication section, and non-AP STA 2 (330) may become a member of the R-TWT SP by sending a TWT setup frame to AP 1 (310), but this is for convenience of explanation only and is not limited thereto.

[0087] AP 1 (310) can detect the communication period of OBSS (i.e., TXOP of OBSS) before the low-latency communication period begins. Specifically, AP 1 (310) can receive a request to send (RTS) frame (401) from OBSS. The medium access control (MAC) header of the RTS frame (401) may include a duration field indicating the length of the TXOP of OBSS. Alternatively, AP 1 (310) may receive an initial control frame (ICF) from OBSS that initiates a TXOP other than the RTS frame. Here, the length of the TXOP can be determined through the physical layer (PHY) header or the MAC header.

[0088] An OBSS TXOP may override the start time of the R-TWT SP directed by AP 1 (310). In the above case, AP 1 (310) may receive an RTS frame (401) from OBSS and, after a short inter-frame space (SIFS), transmit a CTS (clear to send) frame (402) with the recipient address set to the address of AP 1 (310). AP 1 (310) may set the length field of the L-SIG in the PHY header (preamble) of the CTS frame (402) to 0 or set a value expected to be different from that of the CTS frame (403) of OBSS. That is, AP 1 (310) may induce a collision between the CTS frame (403) transmitted from OBSS and the CTS frame of AP 1 (310) so that decoding of the CTS frame (403) transmitted from OBSS becomes impossible.

[0089] As another example, AP 1 (310) may set the length field of the L-SIG to 0 or transmit only the PHY header, which is set to be different from the CTS frame (403) of the OBSS, and not transmit the body of the PPDU (physical layer protocol data unit). Based on the above, the transmission of the CTS frame (403) transmitted in response to the RTS frame (401) from the OBSS fails, and the communication node (e.g., STA X or AP X) that transmitted the RTS frame (401) from the OBSS may attempt to retransmit it. Non-AP STA 1 (320) and non-AP STA 2 (330) may have received the RTS frame (401) from the OBSS, but the reception of the CTS frame (403) from the OBSS may fail because AP 1 (310) induced a collision with the CTS frame. Accordingly, non-AP STA 1 (320) and non-AP STA 2 (330) can initialize the NAV corresponding to the TXOP length of the OBSS set due to the reception of the OBSS RTS frame (401). AP 1 (310) can perform a channel access operation (EDCA backoff operation and EDCA TXOP acquisition procedure) again after transmitting the aforementioned collision-inducing CTS frame (402). AP 1 (310) can use a channel access method that utilizes a defer signal (DS) to perform channel access quickly. When AP 1 (310) uses DS, AP 1 (310) can transmit DS when the channel is idle for a certain period of time (e.g., DIFS (data interframe space)). Here, DS may be a CTS frame (404). AP 1 (310) can perform a short backoff operation after transmitting DS, and if the backoff operation is successful, transmit a frame.

[0090] Referring to FIG. 5a, AP 1 (310) may transmit a frame capable of setting NAV before the start of the R-TWT SP (e.g., a frame transmission to STA 1), or may initiate the transmission of a downlink frame or a trigger frame early to a non-AP STA 2 (330), which is a member STA of the R-TWT SP. As an example, the frame capable of setting NAV before the start of the R-TWT SP described above may be a CTS frame in which a specific non-AP STA is the recipient, or a CTS-to-Self frame in which the recipient is AP 1 (310) itself. As another example, the frame capable of setting NAV may be an initial control frame (ICF), but is not limited thereto. As described above, AP 1 (310) and non-AP STA 1 (320) and non-AP STA 2 (330) connected to AP 1 (310) can occupy the medium before the start of the R-TWT SP, and AP 1 (310) and non-AP STA 2 (330) can perform low-latency frame transmission in the R-TWT SP.

[0091] Referring to FIG. 5b, AP 1 (310) may transmit a frame (quiet frame, 405) that prevents OBSS from performing channel access prior to the start of the R-TWT SP. The frame (405) may include a Quiet element or a Quiet channel element. Alternatively, it may include both a Quiet element and a Quiet channel element. The quiet frame (405) may be a frame that sets NAV to prevent OBSS from performing frame transmission for 1 TU from the start of the R-TWT SP. When the above-mentioned frame is transmitted, OBSS may be unable to transmit frames at the start of the R-TWT SP. Thus, AP 1 (310) and non-AP STA 2 (330), a member of the R-TWT SP, may have priority for channel access in the R-TWT SP. For example, 1 TU may be 1024 us.

[0092] FIG. 6 is a diagram showing a low-latency communication section operation method during wireless LAN subchannel access operation applied to the present disclosure.

[0093] Referring to FIG. 6, AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330) can perform an NPCA operation by moving the operation channel from the primary channel (PCH) to the NPCA primary channel (NPCH) when they detect a TXOP of OBSS, or similarly to FIG. 4a and 4b. Additionally, AP 1 (310) can perform the R-TWT SP instruction operation described above. That is, AP 1 (310) can set the R-TWT SP, non-AP STA 1 (320) is not a member of the R-TWT SP, and non-AP STA 2 (330) is a member of the R-TWT SP.

[0094] Here, the communication period of the OBSS (i.e., the TXOP of the OBSS) can be detected before the R-TWT SP, which is the low-latency communication period, begins. The communication period of the OBSS may overlap with all or part of the low-latency communication period. During the TXOP period of the OBSS, AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330) may operate in the NPCH. In the above case, AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330) may not apply the operations performed in the low-latency communication period in the NPCH. That is, AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330) do not need to perform the operation that causes the frame exchange to end before the start of the low-latency communication period (the operation that causes the TXOP to end before the start of the low-latency communication period). Specifically, AP 1 (310), non-AP STA 1 (320) and non-AP STA 2 (330) may need to terminate the TXOP before the start time of the low-latency communication period, but the above-described operation may be ignored in the NPCH. That is, AP 1 (310), non-AP STA 1 (320) and non-AP STA 2 (330) may determine that the low-latency communication period has not started and perform frame (406, 407) exchange in the NPCH.

[0095] AP 1 (310), non-AP STA 1 (320) and non-AP STA 2 (330) may terminate frame transmission before the TXOP termination time of OBSS, before the switching delay time, which is the time for AP 1 (310) to switch the operating channel back to the main channel from the NPCH.

[0096] When the period of operation in NPCH overlaps with the R-TWT SP, AP 1 (310), non-AP STA 1 (320), and non-AP STA 2 (330) can start the R-TWT SP at the time of switching from NPCH to PCH. That is, the start time of the R-TWT SP may be delayed. Since non-AP STA 1 (320) is not a member of the R-TWT SP, it cannot use the channel access operation immediately at the time of switching the operation channel from NPCH to PCH. For example, non-AP STA 1 (320) can perform the channel access operation after a certain time (e.g., 1 TU). On the other hand, AP 1 (310) that initiated the R-TWT SP and the STA that is a member of the R-TWT SP can perform the channel access operation immediately at the time of switching the operation channel from NPCH to PCH. That is, they can start the TXOP.

[0097] As another example, if the operating period in NPCH overlaps with the R-TWT SP, AP 1 may initiate the R-TWT SP by transmitting at least one of a management frame (e.g., an action frame such as a beacon frame, a probe response frame, or a TWT information frame) or other frames immediately (immediately after a successful channel access operation) or after a certain period of time from the time it starts operating in PCH. That is, the start time of the R-TWT SP may be delayed.

[0098] FIG. 7 is a flowchart illustrating the operation of an STA in a wireless LAN to which the present disclosure applies. Referring to FIG. 7, the STA can set a low-latency communication interval (S710). Here, the low-latency communication interval may be a communication interval where only the STA members of the low-latency communication interval can transmit and receive frames. The STA can detect a transmission within the OBSS before the start point of the low-latency communication interval and switch the operating channel from the main channel to the NPCA channel based on the time interval corresponding to the transmission within the OBSS (S720). After that, if the STA switches the operating channel to the NPCA channel and the NPCA operating interval operating in the NPCA channel overlaps with the low-latency communication interval, the low-latency communication interval can be started in the NPCA channel (S730). Here, the acquisition of a transmission opportunity (TXOP) based on channel access in the NPCA channel can be granted without restriction regardless of the STA type. Additionally, the STA is a non-AP STA connected to an AP (access point), and when the STA sets a TXOP in an NPCA channel, the STA may set the TXOP so that the TXOP is terminated before the start of the low-latency communication period in the NPCA channel. Alternatively, the STA is a non-AP STA connected to an AP, and when the STA sets a TXOP in an NPCA channel, the STA may terminate the TXOP by transmitting a CF (contention free)-end frame before the start of the low-latency communication period. Additionally, in an NPCA channel, the STA is granted the acquisition of a transmission opportunity (TXOP) based on channel access, and at least one STA connected to the STA may not be granted the acquisition of a TXOP based on channel access in the NPCA channel.Additionally, if an STA sets up a TXOP to perform frame exchange with a STA other than a member STA of the low-latency communication segment in an NPCA channel, the STA may set up the TXOP so that it terminates before the start of the low-latency communication segment in the NPCA channel. Additionally, if an STA sets up a TXOP to perform frame exchange with a STA other than a member STA of the low-latency communication segment in an NPCA channel after the start of the low-latency communication segment, the STA may terminate the TXOP by transmitting a CF (contention free)-end frame before the start of the low-latency communication segment. Additionally, if an STA sets up a TXOP to perform frame exchange with a STA that is a member STA of the low-latency communication segment in an NPCA channel, the STA may set up the TXOP regardless of whether the low-latency communication segment in the NPCA channel has started. Additionally, the STA may be an AP STA.

[0099] Alternatively, when the time interval corresponding to the transmission within the OBSS ends, the STA may switch the operating channel from the NPCA channel to the main channel. The TXOP set in the low-latency communication interval may be terminated before the switching delay from the time when the STA switches from the NPCA channel to the main channel. Additionally, if the low-latency communication interval is maintained after the STA switches the operating channel from the NPCA channel to the main channel, only the STA and the low-latency communication interval member STA connected to the STA may be granted TXOP acquisition based on channel access while the low-latency communication interval is maintained after switching the operating channel to the main channel. Alternatively, if the low-latency communication interval is maintained after the STA switches the operating channel from the NPCA channel to the main channel, while the low-latency communication interval is maintained after switching the operating channel to the main channel, the STA may be granted TXOP acquisition based on channel access, and the low-latency communication interval member STA connected to the STA may not be granted the said TXOP acquisition based on channel access. For example, the STA can be an AP STA or a non-AP STA. Also, for example, the low-latency communication period can be an R-TWT (restricted target wake time) SP (service period).

[0100] FIG. 8 is a flowchart illustrating the operation of an STA in a wireless LAN to which the present disclosure applies. Referring to FIG. 8, the STA can set a low-latency communication interval (S810). Here, the low-latency communication interval may be a communication interval where only the STA members of the low-latency communication interval can transmit and receive frames. The STA can detect transmission within the OBSS before the start point of the low-latency communication interval and switch the operating channel from the main channel to the NPCA channel based on the time interval corresponding to the transmission within the OBSS (S820). If the NPCA operating interval operating in the NPCA channel overlaps with the low-latency communication interval after the STA switches the operating channel to the NPCA channel, the STA can start the low-latency communication interval by switching the operating channel from the NPCA channel to the main channel after the NPCA operating interval ends (S830). That is, if the NPCA operating interval and the low-latency communication interval overlap, the STA can start the low-latency communication interval by switching the operating channel back to the main channel after the NPCA operating interval ends. Therefore, the low-latency communication period may be delayed. That is, the start time of the R-TWT SP may be delayed. Here, an STA that is not a member of the low-latency communication period cannot use the channel access operation immediately when the operation channel is switched to the main channel. On the other hand, an STA that is a member of the low-latency communication period can perform the channel access operation immediately when the operation channel is switched to the main channel after the NPCA operation period ends. That is, an STA that is a member of the low-latency communication period can start a TXOP. Alternatively, an STA that is a member of the low-latency communication period may start the low-latency communication period by transmitting at least one of a management frame (e.g., an action frame such as a beacon frame, a probe response frame, or a TWT information frame) or other frames immediately (immediately after the success of the channel access operation) or after a certain period of time when starting the operation on the main channel.

[0101] 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.

[0102]

[0103] The above-mentioned matters may also be applied to other systems.

Claims

1. In the method of operation of a station (STA) in a wireless LAN system, The step of the above STA establishing a low-latency communication section is that the low-latency communication section is a communication section in which only the low-latency communication section member STA can transmit and receive frames; The step of the STA detecting a transmission within an overlapping basic service set (OBSS) prior to the start point of a low-latency communication interval, and switching the operating channel from a primary channel to a non-primary channel access (NPCA) channel based on a time interval corresponding to the transmission within the OBSS; and A method of operation comprising the step of starting the low-latency communication section in the NPCA channel when the NPCA operation section operating in the NPCA channel overlaps with the low-latency communication section after the STA switches the operation channel to the NPCA channel.

2. In Paragraph 1, A method of operation in which the acquisition of a transmission opportunity (TXOP) based on channel access in the above NPCA channel is granted without restriction regardless of the STA type.

3. In Paragraph 2, A method of operation in which the above STA is a non-AP STA connected to an AP (access point), and when the above STA sets the above TXOP in the above NPCA channel, the above STA sets the above TXOP so that the above TXOP is terminated before the start of the low-latency communication section in the above NPCA channel.

4. In Paragraph 2, A method of operation in which the above STA is a non-AP STA connected to an AP, and when the above STA sets the above TXOP in the above NPCA channel, the above STA terminates the above TXOP by transmitting a CF (contention free)-end frame before the start of the low-latency communication section.

5. In Paragraph 1, A method of operation in which, in the above NPCA channel, the STA is granted to acquire a transmission opportunity (TXOP) based on channel access, and at least one STA connected to the STA is not granted to acquire the TXOP based on channel access in the above NPCA channel.

6. In Paragraph 5, A method of operation in which, when the STA sets a TXOP that performs frame exchange with a STA other than a member STA of the low-latency communication section in the NPCA channel, the STA sets the TXOP such that the TXOP is terminated before the start of the low-latency communication section in the NPCA channel.

7. In Paragraph 5, A method of operation in which, if a TXOP in which the STA performs frame exchange with another STA other than the low-latency communication section member STA in the NPCA channel is set after the start time of the low-latency communication section, the STA transmits a CF (contention free)-end frame before the start time of the low-latency communication section to terminate the TXOP.

8. In Paragraph 5, A method of operation in which, when the above STA sets a TXOP that performs frame exchange with a STA that is a member STA of a low-latency communication section in the above NPCA channel, the above STA sets the TXOP regardless of whether the low-latency communication section in the above NPCA channel has started.

9. In Paragraph 5, The above STA is an AP STA, a method of operation.

10. In Paragraph 1, A method of operation in which, when the time interval corresponding to the transmission within the above OBSS ends, the STA switches the operating channel from the NPCA channel to the main channel.

11. In Paragraph 10, A method of operation in which a TXOP set in the above low-latency communication section is terminated before the switching delay from the point in time when the STA switches from the NPCA channel to the main channel.

12. In Paragraph 10, A method of operation in which, when the low-latency communication interval is maintained after the STA switches the operating channel from the NPAC channel to the main channel, only the STA and the low-latency communication interval member STA connected to the STA are allowed to acquire the TXOP based on channel access while the low-latency communication interval is maintained after switching the operating channel to the main channel.

13. In Paragraph 9, A method of operation in which, when the low-latency communication interval is maintained after the STA switches the operating channel from the NPCA channel to the main channel, the STA is granted the acquisition of the TXOP based on channel access while the low-latency communication interval is maintained after switching the operating channel to the main channel, and the low-latency communication interval member STA connected to the STA is not granted the acquisition of the TXOP based on channel access.

14. In Paragraph 1, The above STA is an AP STA or a non-AP STA, a method of operation.

15. In Paragraph 1, The above low-latency communication interval is an operation method in which the R-TWT (restricted target wake time) SP (service period).

16. In the method of operation of a station (STA) in a wireless LAN system, The step of the above STA establishing a low-latency communication section is that the low-latency communication section is a communication section in which only the low-latency communication section member STA can transmit and receive frames; The step of the STA detecting a transmission within an overlapping basic service set (OBSS) prior to the start point of a low-latency communication interval, and switching the operating channel from a primary channel to a non-primary channel access (NPCA) channel based on a time interval corresponding to the transmission within the OBSS; and A method of operation comprising the step of, when the STA switches the operating channel to the NPCA channel and the NPCA operating section operating in the NPCA channel overlaps with the low-latency communication section, the STA switches the operating channel from the NPCA channel to the main channel after the NPCA operating section ends, thereby starting the low-latency communication section.

17. In a wireless LAN system, regarding a station (STA), At least one transceiver for transmitting and receiving signals; At least one processor controlling the above-mentioned at least one transmitting and receiving unit; and It includes a memory that stores instructions for the non-AP STA to perform a specific operation by the above at least one processor, and The above specific operation is: A low-latency communication section is established, wherein the low-latency communication section is a communication section in which only the low-latency communication section member STA can transmit and receive frames, and Detecting a transmission within an overlapping basic service set (OBSS) prior to the start point of a low-latency communication section, and switching the operating channel from a primary channel to a non-primary channel access (NPCA) channel based on a time interval corresponding to the transmission within the OBSS, and STA that starts the low-latency communication section in the NPCA channel when the NPCA operation section operating in the NPCA channel overlaps after switching the operation channel to the NPCA channel.

18. 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: A low-latency communication section is established, wherein the low-latency communication section is a communication section in which only the low-latency communication section member STA can transmit and receive frames, and Detecting a transmission within an overlapping basic service set (OBSS) prior to the start point of a low-latency communication section, and switching the operating channel from a primary channel to a non-primary channel access (NPCA) channel based on a time interval corresponding to the transmission within the OBSS, and STA that, when the NPCA operation section operating on the NPCA channel overlaps with the low-latency communication section after switching the operation channel to the NPCA channel, starts the low-latency communication section when the operation channel is switched from the NPCA channel to the main channel after the NPCA operation section ends.

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