Method and device for performing low latency operation while performing power saving operation in wireless LAN

Abstract

An operation method of an AP in a wireless LAN system comprises: a step in which the AP transmits a first frame, wherein the AP supports a DPS operation and the first frame includes DPS operation-related information about the AP; a step in which the AP transmits a beacon frame, wherein the beacon frame includes beacon-related time period information about the AP; and a step for performing communication with a non-AP STA on the basis of the beacon-related time period information, wherein when the DPS operation-related information indicates an HCM operation during a periodic time period corresponding to the beacon-related time period information, the AP may maintain an HCM during the periodic time period corresponding to the beacon-related time period information.

Description

Method and device for performing low-latency operation while performing low-power operation in a wireless LAN

[0001] The present disclosure relates to a method and apparatus for transmitting low-latency traffic in a wireless local area network that supports dynamic power saving operation.

[0002]

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

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

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

[0006] The following describes a method for performing low-latency communication while performing low-power operation in a wireless LAN as described above.

[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 and apparatus for transmitting low-latency traffic in a wireless LAN that supports dynamic power-saving operation.

[0010] The present disclosure relates to a method and apparatus for performing efficient low-power communication by disabling the low-power operation in a preset low-latency communication interval of a wireless LAN terminal performing a low-power operation.

[0011] The present disclosure relates to a method and apparatus for reducing overhead by transmitting low-latency frames with low-power operation in a low-latency communication section.

[0012] The present disclosure relates to a method and apparatus for improving the low-latency performance of a wireless LAN network by having a wireless LAN terminal supporting low-power operation efficiently transmit low-latency data frames in a low-latency communication section.

[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 an access point (AP) in a wireless LAN system comprises the step of the AP transmitting a first frame, wherein the AP supports dynamic power saving (DPS) operation and the first frame includes information related to the AP's DPS operation, and the step of the AP transmitting a beacon frame, wherein the beacon frame includes information related to the AP's beacon time period and performs communication with a non-AP STA based on the information related to the beacon time period, wherein if the information related to the DPS operation indicates a higher capability mode (HCM) operation during a periodic time interval corresponding to the information related to the beacon time period, the AP may maintain the HCM during the periodic time interval corresponding to the information related to the beacon time period.

[0016] Additionally, according to one embodiment of the present specification, an access point (AP) 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 the AP to perform a specific operation by the at least one processor, wherein the specific operation comprises: transmitting a first frame, wherein the AP supports dynamic power saving (DPS) operation, and the first frame includes information related to the AP's DPS operation, and transmitting a beacon frame, wherein the beacon frame includes information related to the AP's beacon time period, and performing communication with a non-AP STA based on the information related to the beacon time period, wherein if the information related to the DPS operation indicates a higher capability mode (HCM) operation during a periodic time interval corresponding to the information related to the beacon time period, the AP may maintain the HCM during the periodic time interval corresponding to the information related to the beacon time period.

[0017] In addition, according to one embodiment of the present specification, a method of operation of a non-access point (AP) STA in a wireless LAN system comprises the step of the non-AP STA receiving a first frame, wherein the AP supports dynamic power saving (DPS) operation and the first frame includes information related to the AP's DPS operation, the step of the non-AP STA receiving a beacon frame, wherein the beacon frame includes information related to the AP's beacon-related time period, and the step of performing communication with the AP based on the information related to the beacon-related time period, wherein if the information related to the DPS operation indicates a higher capability mode (HCM) operation during a periodic time interval corresponding to the information related to the beacon-related time period, the AP may maintain the HCM during the periodic time interval corresponding to the information related to the beacon-related time period.

[0018] Additionally, according to one embodiment of the present specification, a non-access point (AP) 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 the non-AP STA to perform a specific operation by the at least one processor, wherein the specific operation is: receiving a first frame, wherein the AP supports dynamic power saving (DPS) operation, and the first frame includes information related to the AP's DPS operation; receiving a beacon frame, wherein the beacon frame includes information related to the AP's beacon time period; and performing communication with the AP based on the information related to the beacon time period, wherein if the information related to the DPS operation indicates a higher capability mode (HCM) operation during a periodic time interval corresponding to the information related to the beacon time period, the AP may maintain the HCM during the periodic time interval corresponding to the information related to the beacon time period.

[0019] In addition, the following points may apply in common.

[0020] According to one embodiment of the present specification, a periodic time interval corresponding to beacon-related time period information may include at least one of a target beacon transmission time (TBTT) and a R (restricted)-TWT (target wake time) SP (service period).

[0021] In addition, according to one embodiment of the present specification, the periodic time interval is TBTT, and the AP transmits a first frame containing DPS operation-related information indicating HCM operation, and can maintain HCM until the time of transmission of the next beacon frame based on TBTT.

[0022] Additionally, according to one embodiment of the present specification, the periodic time interval is R-TWT SP, and AP can maintain HCM during the R-TWT SP interval based on DPS operation-related information indicating HCM operation.

[0023] In addition, according to one embodiment of the present specification, when an AP communicates with a non-AP STA during a periodic time interval based on beacon-related time interval information, a transmission opportunity (TXOP) for frame exchange with the non-AP STA is set, and when the TXOP exceeds the periodic time interval, the AP can maintain the HCM until the TXOP ends.

[0024] In addition, according to one embodiment of the present specification, when an AP communicates with a non-AP STA during a periodic time interval based on beacon-related time interval information, a transmission opportunity (TXOP) for frame exchange with the non-AP STA is set, and when the TXOP exceeds the periodic time interval, the AP can switch from HCM to a lower capability mode (LCM) and operate regardless of the TXOP end time when the periodic time interval ends.

[0025] In addition, according to one embodiment of the present specification, when an AP communicates with a non-AP STA during a periodic time interval based on beacon-related time period information, a transmission opportunity (TXOP) for frame exchange with the non-AP STA is set, and the TXOP may expire before the end of the periodic time interval.

[0026] Additionally, according to one embodiment of the present specification, the AP may operate in any one of an HCM capable of general transmit and receive operations based on DPS operation, or a lower capability mode (LCM) in which at least one of the operation bandwidth, the number of operation space streams, and the MCS is limited, or only the reception of an initial control frame is possible.

[0027] In addition, according to one embodiment of the present specification, the HCM may be an operating mode without any restrictions other than the upper limit of the operating capability of the wireless LAN terminal.

[0028] In addition, according to one embodiment of the present specification, when an AP communicates with a non-AP STA during a periodic time interval based on beacon-related time period information, the AP performs frame exchange with the non-AP STA that is maintained as HCM, and when the periodic time interval ends, the AP and the non-AP STA may switch from HCM to LCM.

[0029] In addition, according to one embodiment of the present specification, when an AP communicates with a non-AP STA during a periodic time interval based on beacon-related time period information, the AP can transmit a trigger frame to the non-AP STA and receive an uplink frame from the non-AP STA based on the trigger frame.

[0030] In addition, according to one embodiment of the present specification, when an AP communicates with a non-AP STA during a periodic time interval based on beacon-related time period information, if there is no data to be transmitted to the non-AP STA, the AP may transmit a periodic time interval early termination frame and then terminate the periodic time interval early.

[0031] Additionally, according to one embodiment of the present specification, when an AP receives an indicator from a non-AP STA indicating that there is no frame to transmit, the AP may transmit a periodic time interval early termination frame and then terminate the periodic time interval early.

[0032] In addition, according to one embodiment of the present specification, when an AP communicates with a non-AP STA during a periodic time interval based on beacon-related time period information, the AP operates as an LCM during the periodic time interval, and when it receives an initial control frame from the non-AP STA in the LCM, it can switch to an HCM and operate.

[0033]

[0034] According to the present disclosure, a method for transmitting low-latency traffic in a wireless LAN that supports low-power operation can be provided.

[0035] According to the present disclosure, a wireless LAN terminal performing low-power operation can provide a method for performing efficient low-power communication by disabling low-power operation in a preset low-latency communication interval.

[0036] According to the present disclosure, a method for reducing overhead can be provided by transmitting low-latency frames with low-power operation in a low-latency communication section.

[0037] According to the present disclosure, a wireless LAN terminal supporting low-power operation can efficiently transmit low-latency data frames in a low-latency communication section to provide a method for improving the low-latency performance of a wireless LAN network.

[0038] 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.

[0039] 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.

[0040]

[0041] FIG. 1 is a diagram showing a communication node within a wireless LAN system to which the present disclosure applies.

[0042] FIG. 2 is a drawing showing a wireless LAN system to which the present disclosure is applied.

[0043] FIG. 3 is a diagram illustrating a method for performing low-latency frame transmission in a wireless LAN network that supports power-saving operations applicable to the present disclosure.

[0044] FIG. 4 is a diagram illustrating a method for performing low-latency frame transmission in a wireless LAN network that supports power-saving operations applicable to the present disclosure.

[0045] FIG. 5 is a diagram illustrating a method for performing low-latency frame transmission in a wireless LAN network that supports power-saving operations applicable to the present disclosure.

[0046] FIG. 6 is a diagram illustrating a method for performing low-latency frame transmission in a wireless LAN network that supports power-saving operations applicable to the present disclosure.

[0047] FIG. 7 is a diagram illustrating a method for performing low-latency frame transmission in a wireless LAN network that supports power-saving operations applicable to the present disclosure.

[0048] FIG. 8 is a diagram illustrating a method for performing low-latency frame transmission in a wireless LAN network that supports power-saving operations applicable to the present disclosure.

[0049] FIG. 9 is a flowchart showing the operation of an AP in a wireless LAN to which the present disclosure applies.

[0050] FIG. 10 is a flowchart illustrating the operation of a non-AP STA in a wireless LAN to which the present disclosure applies.

[0051]

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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."

[0059] 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.

[0060] 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).

[0061] 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).

[0062] 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).

[0063] 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.

[0064] 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.

[0065] In a wireless LAN, when a wireless LAN terminal performs low-power operation and low-latency communication, a method for efficiently transmitting low-latency frames may be required. For example, when a wireless LAN terminal performs low-power operation, overhead may occur or low-latency frame transmission may become impossible due to the terminal's limited frame transmission capability. In such cases, the low-latency performance of the wireless LAN may be reduced. Considering the above, the following describes a method for a wireless LAN terminal performing low-power operation to disable low-power operation during a preset low-latency communication interval to perform efficient low-power communication.

[0066] In a wireless LAN network, communication between AP 1 and non-AP STA 1 operating in association with AP 1 can be considered. However, this is for convenience of explanation only and is not limited thereto. In a wireless LAN network, AP 1 can perform power-saving operations. Here, the power-saving operation may be a low-power operation. When AP 1 performs a power-saving operation, one of the power-saving modes in which AP 1 can operate may be a doze mode, in which reception of all frames is impossible and channel detection is also impossible. Another power-saving mode in which AP 1 can operate may be a lower capability mode (LCM), which has fewer restrictions than doze mode. In LCM, at least one of the operating bandwidth, operating space stream, and modulation coding scheme (MCS) of AP 1 may be limited. Meanwhile, the AP performing the DPS operation may be a mobile AP or an AP included in a mobile AP MLD, but is not limited thereto.

[0067] Alternatively, AP 1 may be able to receive only frames of a specific format from the LCM. Frames of a specific format may be initial control frames (ICF), but are not limited thereto. Initial control frames may be at least one of a BlockAck request (BAR) frame, a request to send (MU) trigger frame, a buffer status report poll (BSRP) trigger frame, and other frames, and are not limited to a specific form.

[0068] Additionally, AP 1 can operate in a higher capability mode (HCM). When AP 1 operates in HCM, AP 1 can perform normal data transmission and reception, and the operating bandwidth and operating space streams in AP 1 may not be limited. Here, power consumption is lowest when AP 1 operates in Doze mode, and power consumption may be highest when operating in HCM.

[0069] For example, the operation of AP 1 switching from LCM to HCM or switching from HCM to LCM may be a dynamic power saving (DPS) operation. However, this is for convenience of explanation only and is not limited to that name. AP 1 can receive an ICF in LCM. If AP 1 receives an ICF in LCM, AP 1 may switch from LCM to HCM and operate. That is, if AP 1 receives an initial control frame in LCM and intends to perform data communication, AP 1 may switch from LCM to HCM. However, AP 1 may not switch to HCM if it receives an initial control frame in LCM but prioritizes power saving. As another example, if AP 1 needs to perform a frame transmission operation, AP 1 may operate in HCM even if it has not received an ICF. HCM may be a mode that allows the use of the same communication parameters as the operation without the aforementioned DPS operation. For example, AP 1 may be able to perform data transmission and reception operations without any separate restrictions, except for the upper limit of the basic operational capability (e.g., software and / or hardware constraints, etc.) when AP 1 does not use DPS operation in HCM.

[0070] When AP 1 performs DPS operation, LCM may be the default operation mode of AP 1. However, if AP 1 sets a time interval for low-latency frame exchange, or a time interval based on the beacon period, AP 1 may operate as HCM during that time interval, and detailed operation will be described later.

[0071] There may be low-latency frames that need to be transmitted (or received) on non-AP STA 1. Therefore, non-AP STA 1 can perform a stream classification service (SCS) setup procedure to negotiate quality of service (QoS) parameters with AP 1. The SCS negotiation procedure can be performed by non-AP STA 1 sending an SCS request frame to AP 1, and AP 1 sending an SCS response frame in response to non-AP STA 1's SCS request frame. As another example, the SCS negotiation procedure can be performed by AP 1 sending an SCS request frame to non-AP STA 1, and non-AP STA 1 sending an SCS response frame in response to AP 1's SCS request frame. At least one of the SCS request frame and the SCS response frame may include low-latency traffic characteristic information (e.g., period information, delay requirements, EDCA (enhanced distributed channel access) parameter requirements, etc.) that non-AP STA 1 must transmit. For example, the low-latency traffic characteristic information may be QoS parameters, but is not limited thereto. As a result of the SCS negotiation, non-AP STA 1 and AP 1 may establish mutual stream classification (or traffic classification). If stream classification is established, traffic corresponding to the stream classification may be transmitted using separate EDCA parameters or using a separate EDCA queue. Alternatively, traffic corresponding to the stream classification may be transmitted within a low-latency communication interval.As another example, AP 1 and non-AP STA 1 can perform traffic exchange within a periodic time interval based on a beacon frame. The beacon frame may include beacon-related time period information, and AP 1 and non-AP STA 1 can perform traffic exchange within a periodic time interval set according to the beacon-related time period information indicated in the beacon frame. As an example, the low-latency communication interval (or periodic time interval) may include at least one of R (restricted)-TWT (target wake time) SP (service period) and TBTT (target beacon transmission time), but is not limited thereto. For convenience of explanation, the following description is based on the low-latency communication interval and R-TWT SP, but the same applies to the periodic time interval and TBTT. Additionally, the TWT SP of the present disclosure including the R-TWT SP may be a periodic time interval set based on TBTT. The TWT SP of the present disclosure, including the above R-TWT SP, may be a time interval set to the next TBTT. For example, the TWT SP may be set to a time interval set to the next TBTT from the time of transmission of a management frame containing a beacon frame containing a TWT element indicating the TWT SP. Meanwhile, the time interval to the next TBTT may be a time interval scheduled (i.e., pre-set) for the time of transmission start or completion of the beacon frame, or it may be until the time when the next beacon frame is actually completed.

[0072] AP 1 can set an R-TWT SP that matches the low-latency traffic characteristics (i.e., QoS parameters, QoS characteristics) exchanged during the SCS negotiation procedure so that traffic corresponding to the stream classification can be transmitted first. For example, the period of the R-TWT SP can be set according to the transmission period of the low-latency traffic. That is, the R-TWT SP can be a periodic communication interval (e.g., target beacon transmission time, TBTT) based on the beacon period. Here, the R-TWT SP can be specified in the broadcast TWT method. The broadcast TWT method may be a method in which the AP transmits a TWT SP containing the R-TWT SP by including the TWT element in at least one of a beacon frame, a probe response frame, or other frames transmitted via broadcast. Through this, STAs receiving the frames transmitted by the AP can verify the TWT SP information.

[0073] AP 1 can transmit a beacon frame including a TWT element indicating an R-TWT SP. Since the R-TWT SP is indicated by a broadcast TWT method, the TWT element may include beacon period information (e.g., target beacon transmission time, TBTT) or periodic time interval information that starts based on the beacon period information. AP 1 may include a TWT ID, which is an identifier for identifying the TWT, in the TWT element indicating the R-TWT SP. Additionally, as an example, the negotiation type subfield of the TWT element indicating the R-TWT SP may indicate a broadcast TWT (e.g., a value of 2 or 3, but not limited thereto), which is a time interval set based on the beacon period. Additionally, the setup command field of the TWT element indicating the R-TWT SP may be set to a Request TWT, Suggest TWT, or Demand TWT. AP 1 manages the membership of the broadcast TWT as described above and can indicate that a new TWT member STA can participate. non-AP STA 1 checks the TWT elements included in the beacon frame of AP 1 and can identify the R-TWT SP indicated by AP 1. To operate as a member capable of communicating low-latency traffic in the configured R-TWT SP, non-AP STA 1 can send a frame (e.g., a TWT information frame) containing a TWT element with the TWT configuration command field set to Accept TWT to AP 1. Subsequently, non-AP STA 1 can become a member of AP 1's R-TWT SP. Becoming a member of AP 1's R-TWT SP or TWT SP may mean becoming a member of AP 1's R-TWT or TWT. non-AP STA 1 can subsequently participate as a member in multiple R-TWT SPs set up by AP 1.

[0074] AP 1 can indicate whether AP 1 performs a DPS operation after transmitting a beacon frame through a separate element (e.g., DPS element) or a separate field (e.g., DPS operation parameters field) included in the beacon frame of AP 1. The said separate element or said separate field may be included in an ultra-high reliability (UHR) operation element included in the beacon frame, or may be included in another management frame containing the beacon frame transmitted by the AP. If AP 1 performs a DPS operation, AP 1 may transmit a beacon frame containing the said separate field (DPS operation parameters field) in the UHR operation element. As another example, AP 1 may transmit a separate frame containing the aforementioned separate elements (e.g., a management frame containing a DPS action frame including a DPS field indicating the DPS operation of AP 1, a link reconfiguration frame, an OMP (operation mode and parameters) frame, a probe request frame, etc.) and indicate whether AP 1 performs a DPS operation after transmitting the said frame. The DPS field included in the beacon frame or the aforementioned separate frame may include a TWT ID indicating an R-TWT SP. Here, AP 1 may indicate whether to operate as HCM, which is one of the operation modes of the DPS operation, in the R-TWT SP, which is a low-latency communication section. In the present disclosure, the DPS field may be the aforementioned DPS operation parameters field, DPS element, and other forms.Additionally, the DPS field may be a separate field, element, or frame indicating DPS operation parameters, and is not limited to a specific form.

[0075] For example, AP 1 can indicate that it operates in HCM mode in the R-TWT SP corresponding to the TWT ID. That is, AP 1 can operate in a mode that enables rapid frame transmission and reception during low-latency communication intervals. Additionally, the aforementioned R-TWT SP may be a periodic communication interval based on the beacon period. Therefore, non-AP STA 1 receives a frame containing the DPS field of AP 1 and can recognize that AP 1 operates in HCM mode in the R-TWT SP of AP 1. As another example, if the R-TWT SP corresponding to the TWT ID does not contain an indicator indicating whether to operate in HCM mode, AP 1 can operate in HCM mode in the R-TWT SP by default. That is, non-AP STA 1 can recognize that AP 1 operates in HCM mode in the R-TWT SP of AP 1 when the DPS field does not contain an indicator indicating whether to operate in HCM mode. Alternatively, since the default operating mode of AP 1 is LCM, it may be possible for AP 1 to operate as LCM in R-TWT SP by default. In the above case, AP 1 operates as HCM in R-TWT SP only when it is instructed to operate as HCM in R-TWT SP corresponding to TWT ID, and otherwise it may operate as LCM.

[0076] Here, the operation described above may be the operation of AP 1 in the R-TWT SP corresponding to the TWT ID. However, AP 1 may intend to operate as HCM in the periodic communication interval based on all beacon periods (including the R-TWT SP). non-AP STA 1 may receive a frame containing the DPS field of AP 1, and AP 1 may operate as HCM in the periodic communication interval based on the beacon period.

[0077] Additionally, AP 1 can operate as an LCM after transmitting a frame (e.g., a Beacon frame) containing a DPS field. While operating as an LCM, AP 1 may receive an initial control frame from non-AP STA 1 and other connected STAs. When AP 1 receives an initial control frame, AP 1 may operate as an HCM to perform data transmission and reception, and may return to operating as an LCM once the data transmission and reception operation is completed. AP 1, while operating as an LCM, may operate as an HCM at the start of a communication interval based on a beacon period that includes an R-TWT SP. In this disclosure, the R-TWT SP is a communication interval based on a beacon period. As described above, AP 1 indicates that it will operate as an HCM at the R-TWT SP indicated by the DPS field, and based on this, may operate as an HCM at the start of the R-TWT SP. Since non-AP STA 1 recognizes that AP 1 is operating as an HCM in the R-TWT SP, it can transmit uplink data frames to the HCM once the channel access procedure (e.g., EDCA backoff procedure) is completed without transmitting an initial control frame or a separate additional waiting procedure. AP 1 can transmit downlink data frames to non-AP STA 1 while operating as an HCM in the R-TWT SP. Here, at least one of the uplink data frames and downlink data frames transmitted within the R-TWT SP may be a low-latency data frame corresponding to the traffic classification negotiated in the SCS negotiation procedure. However, the communication interval based on the beacon period including the R-TWT SP may not be established by the aforementioned SCS procedure. For example, it may be established by considering the traffic conditions of AP 1 or non-AP STA 1 connected to AP 1, and may not be limited to a specific form.

[0078] Here, the above-described matters may be applied in the same way to FIGS. 3 to 8 below. Although some configurations may be changed or operations may differ depending on the operation in each figure, the above-described operations may be applied to FIGS. 3 to 8 for other operations.

[0079] FIG. 3 is a diagram illustrating a method for performing low-latency frame transmission in a wireless LAN network that supports power-saving operations applicable to the present disclosure.

[0080] Referring to FIG. 3, AP 1 (310) and non-AP STA 1 (320) can perform an SCS setup procedure for the QoS parameter negotiation described above. In the SCS negotiation procedure, non-AP STA 1 (320) can send an SCS request frame (401) to AP 1 (310), and AP 1 (310) can send an SCS response frame (402) in response to the SCS request frame (401) of non-AP STA 1 (320), but is not limited thereto, and it may also be possible for AP 1 (310) to send the SCS request frame (401) first. As a result of the SCS negotiation, non-AP STA 1 (320) and AP 1 (310) can set mutual stream classification (or traffic classification), and traffic corresponding to the stream classification can be transmitted using separate EDCA parameters or using a separate EDCA queue. In addition, traffic corresponding to stream classification can be transmitted within the R-TWT SP, which is a low-latency communication section, as described above.

[0081] Additionally, AP 1 (310) may transmit a beacon frame (403). The beacon frame (403) may include at least one of a DPS field or a DPS operation parameter field, and based on this, AP 1 (310) may indicate whether to perform a DPS operation after transmitting the beacon frame. As another example, AP 1 (310) may also transmit a separate frame containing at least one of a DPS field or a DPS operation parameter field, and is not limited to a specific form. The DPS field included in the beacon frame (403) may include a TWT ID indicating an R-TWT SP. Here, AP 1 (310) may indicate whether to operate as HCM, which is one of the operation modes of the DPS operation, in the R-TWT SP, which is a low-latency communication section, as described above.

[0082] Here, the operation described above may be the operation of AP 1 (310) in the R-TWT SP corresponding to the TWT ID. However, AP 1 (310) may be intended to operate as HCM in the periodic communication interval based on all beacon periods (including the R-TWT SP). The non-AP STA 1 (320) may receive a frame containing the DPS field of AP 1 (310), and AP 1 (310) may operate as HCM in the periodic communication interval based on the beacon period. That is, it may not be limited to the R-TWT SP corresponding to the TWT ID.

[0083] Additionally, a communication interval based on a beacon cycle including an R-TWT SP may not be established by the SCS procedure described above. For example, it may be established by considering the traffic conditions of AP 1 (310) or non-AP STA 1 (320) connected to AP 1 (310), and is not limited to a specific form.

[0084] Referring to FIG. 3, it can operate as HCM during a periodic communication interval based on a beacon period (e.g., R-TWT SP and N (N is a natural number) or a beacon period (TBTT) communication interval, etc.). The beacon period communication interval is a time interval up to N TBTT or up to the next TBTT. That is, AP 1 (310) operates as HCM during the periodic communication interval described above, and can switch the operation mode to LCM when the periodic communication interval ends. AP 1 (310) can switch the operation mode to HCM during the periodic communication interval and can receive a low-latency data frame (404) from non-AP STA 1 (320) or transmit a low-latency data frame (405) to non-AP STA 1 (320).

[0085] Here, low-latency data frame transmission (e.g., transmission of uplink data frames, transmission of downlink data frames) may proceed beyond the end time of the periodic communication interval. For example, a TXOP (transmit opportunity), which is a time interval during which at least one of transmitting uplink data frames and receiving downlink data frames can be performed with multiple frames, may exceed the end time of the periodic communication interval based on the beacon period. In the above case, AP 1 (310) may operate as an HCM to complete the frame transmission procedure until the ongoing TXOP is completed (i.e., the exchange of data frames is completed). On the other hand, AP 1 (310) may operate as an LCM after the TXOP is completed (i.e., after the exchange of data frames is completed). For example, when AP 1 (310) is terminated by a TXOP, AP 1 (310) may operate in LCM after a DPS Transition Delay from the time of termination of the TXOP (e.g., the time of termination of the last frame transmitted or received by AP 1 (310)) or after a time of 'aSIFSTime + aSlotTime + DPS Transition Delay'. Here, 'aSIFSTime + aSlotTime' may be a delay time for waiting for additional frame reception or transmission by AP 1 (310). If AP 1 (310) receives or transmits a frame within the time of 'aSIFSTime + aSlotTime' (e.g., PHY-RXSTART.indication primitive occurs on AP 1, PHY-TXSTART.confirm and / or PHY-TXSTART.request primitive occurs), AP 1 may maintain the mode of operation as HCM. On the other hand, if AP 1 (310) does not receive a frame or perform a transmission within the time 'aSIFSTime+aSlotTime', AP 1 may switch the operation mode from HCM to LCM.Here, the operation mode switching may take a DPS switching delay. Alternatively, AP 1 (310) may switch the operation mode from HCM to LCM without waiting for additional frame transmission and reception, and the operation mode switching may take a DPS switching delay.

[0086] The above-described TXOP may have been initiated by AP 1 (310) to perform a frame exchange including a data frame with non-AP STA 1 (320), or the above-described TXOP may have been initiated by AP 1 (310) to perform a frame exchange including a data frame with non-AP STA 1 (320).

[0087] As another example, if the TXOP, which is a time interval during which at least one of transmitting uplink data frames and receiving downlink data frames can be performed in multiple frames, exceeds the end time of the periodic communication interval based on the beacon period, AP 1 (310) may switch the operating mode to LCM when the end time of the periodic communication interval arrives, regardless of the end time of the TXOP. As an example, AP 1 (310) may operate as LCM when the end time of the periodic communication interval arrives, regardless of the end time of the TXOP. Here, non-AP STA 1 (320) may need to transmit a frame to AP 1 (310) while AP 1 (310) is operating as LCM when the end time of the periodic communication interval arrives. When non-AP STA 1 (320) transmits a frame to AP 1 (310) (i.e., initiates an additional TXOP), non-AP STA 1 (320) may transmit an ICF to switch AP 1 (310) from LCM to HCM, and based on the ICF, may perform frame transmission when AP 1 (310) switches to HCM. Alternatively, non-AP STA 1 (320) may transmit a frame using communication parameters that match the LCM of AP 1 (310). Based on the above, non-AP STA 1 (320) may transmit a frame to AP 1 (310) within the acquired TXOP.

[0088] As another example, if AP 1 (310) and non-AP STA 1 (320), which is a non-AP STA connected to AP 1 (310), have a TXOP terminated after the current periodic communication period, AP 1 (310) may maintain the HCM operating mode until the periodic communication period (e.g., next TBTT) that is terminated after the TXOP termination time.

[0089] As another example, a different operation may be performed when the TXOP terminates after the periodic communication interval between AP 1 (310) and non-AP STA 1 (320). Here, if the TXOP is a TXOP for non-AP STA 1 (320) to transmit a frame to AP 1 (310), non-AP STA 1 (320) may transmit the frame with communication parameters corresponding to the HCM of AP 1 (310) (e.g., the basic operating capability of AP 1) until TBTT. non-AP STA 1 (320) may terminate frame exchange with AP 1 (310) within TXOP before TBTT (or, at a time before PIFS time from TBTT, at a time before aSIFSTime + aSlotTime + DPS Transition Delay time from TBTT, at a time before aSIFSTime + aSlotTime + DPS Transition Delay + PIFS time from TBTT, at a time before DPS Transition Delay time from TBTT, at a time before DPS Transition Delay + PIFS time from TBTT).

[0090] After that, AP 1 (310) transmits a beacon frame in the next TBTT and can operate as LCM from the time the beacon frame transmission is completed. non-AP STA 1 (320) can assume that AP 1 (310) operates as LCM after AP 1 (310) completes the beacon frame transmission. Therefore, non-AP STA 1 (320) can transmit an ICF to AP 1 (310) to switch the operating mode of AP 1 (310) from LCM to HCM. When AP 1 (310) receives the ICF, it can transmit a frame with communication parameters (e.g., the basic operating capability of AP 1 (310)) that match the HCM of AP 1 (310). As another example, AP 1 (310) can maintain LCM and transmit frames to non-AP STA 1 (320) with communication parameters that match LCM (e.g., LCM operation capability of AP 1 (310)).

[0091] Meanwhile, non-AP STA 1 (320) may consider the time required for AP 1 (310) to switch its operating mode from HCM to LCM within a TXOP. For example, AP 1 (310) may operate as LCM after a DPS Transition Delay time (or aSIFSTime+aSlotTime+DPS Transition Delay) from the time the beacon frame transmission is completed. As another example, if AP 1 (310) transmits a beacon frame from LCM, it may operate as LCM immediately after the beacon frame transmission is completed. Here, non-AP STA 1 (320) cannot transmit a frame to AP 1 (310) during the DPS Transition Delay time (or aSIFSTime+aSlotTime+DPS Transition Delay) starting from the time the beacon frame transmission of AP 1 (310) is completed.

[0092] When AP 1 (310) is operating as an LCM, non-AP STA 1 (320) can transmit frames to AP 1 (310) without a new channel access procedure from the time AP 1 (310) is operating as an LCM or thereafter.

[0093] As another example, non-AP STA 1 (320) may terminate frame exchange before the next TBTT time, wait while performing channel sensing, and transmit frames to AP 1 (310) at or after the time when AP 1 (310) is operating as an LCM.

[0094] As another example, non-AP STA 1 (320) may select a new backoff counter and perform a channel access operation to decrease the backoff counter. If the slot boundary at which the backoff counter becomes zero is when AP 1 (310) is operating as an LCM or later, non-AP STA 1 (320) may transmit additional frames to AP 1 (310). Alternatively, if the slot boundary at which the new backoff counter becomes zero is before the time when AP 1 (310) is operating as an LCM, non-AP STA 1 (320) may select a new backoff counter and perform a new channel access procedure. After that, non-AP STA 1 (320) may transmit additional frames at the slot boundary at which the backoff counter reaches zero at the time when AP 1 (310) is operating as an LCM or later. Specifically, when non-AP STA 1 (320) performs the first frame transmission within a TXOP, it may set a TXNAV timer based on the value of the duration / ID field of the frame's MAC header. non-AP STA 1 (320) may transmit additional frames to AP 1 (310) before the TXNAV timer within the TXOP becomes 0. Conversely, when the TXNAV timer reaches 0, non-AP STA 1 (320) cannot perform frame transmission within the TXOP. When non-AP STA 1 (320) selects a new backoff counter and performs a channel access procedure, it may not be the start of a new TXOP, but a procedure to transmit additional frames within an existing TXOP. Additionally, the TXNAV value may not be extended.

[0095] Additionally, as an example, if the above-described TXOP is a TXOP for AP 1 (310) to transmit a frame to non-AP STA 1 (320), AP 1 (310) can transmit a frame with communication parameters (e.g., the basic operating capability of AP 1) that match the HCM of AP 1 (310) at a time before TBTT (or at a time before PIFS time from TBTT, or at a time before aSIFSTime + aSlotTime + DPS Transition Delay time from TBTT).

[0096] After that, AP 1 (310) can transmit a beacon frame. If AP 1 (310) wishes to transmit a frame in HCM mode even after the beacon frame transmission is complete, it may maintain the operating mode as HCM. In the above case, AP 1 (310) can transmit a beacon frame in HCM mode. AP 1 (310) can transmit a frame with communication parameters (e.g., the basic operating capability of AP 1 (310)) that match the HCM of AP 1 (310) during the remaining TXOP interval. As another example, AP 1 (310) may wish to transmit a frame in LCM mode. To do this, AP 1 (310) may switch the operating mode at a point after or before the beacon frame transmission is complete. When AP 1 (310) switches the operating mode, AP 1 (310) may operate in LCM after a DPS switching delay. If the DPS transition delay of AP 1 (310) is zero or within a certain value (e.g., within SIFS, PIFS time), and AP 1 (310) can immediately transition from HCM to LCM, AP 1 (310) can transmit a frame to non-AP STA 1 (320) in the remaining TXOP interval after SIFS time from the last transmitted frame or received frame. On the other hand, if the transition delay of AP 1 is zero or greater than or exceeds a certain value, AP 1 (310) can select a new backoff counter value and perform a new channel access procedure to transmit a frame to non-AP STA 1 (320) at the slot boundary where the backoff counter reaches zero. Specifically, when AP 1 (310) performs the first frame within the TXOP, it can set a TXNAV timer based on the value of the duration / ID field of the MAC header of the frame. AP 1 (310) can transmit additional frames before the TXNAV timer becomes 0. On the other hand, when the TXNAV timer reaches 0, AP 1 (310) cannot transmit frames.AP 1 (310) selecting a new backoff counter and performing a channel access procedure may not be the start of a new TXOP, but may be a procedure to transmit additional frames within an existing TXOP. Also, the TXNAV value may not be extended.

[0097] As another example, AP 1 (310) and non-AP STA 1 (320), which is a non-AP STA connected to AP 1 (310), may be required to ensure that the TXOP is terminated within the periodic communication interval.

[0098] If the TXOP is a TXOP for non-AP STA 1 (320) to transmit a frame to AP 1 (310), the TXOP of non-AP STA 1 (320) may be terminated before TBTT (or, at a time before PIFS time from TBTT, at a time before aSIFSTime + aSlotTime + DPS Transition Delay time from TBTT, at a time before aSIFSTime + aSlotTime + DPS Transition Delay + PIFS time from TBTT, at a time before DPS Transition Delay time from TBTT, at a time before DPS Transition Delay + PIFS time from TBTT). AP 1 (310) may transmit a beacon frame at the next TBTT. When AP 1 (310) transmits a beacon frame from the HCM, AP 1 (310) may operate as an LCM after a DPS transition delay time (or, aSIFSTime+aSlotTime+DPS Transition Delay) from the time the beacon frame transmission is completed. As another example, when AP 1 (310) transmits a beacon frame from the LCM, AP 1 (310) may operate as an LCM immediately after the beacon frame transmission is completed. non-AP STA 1 (320) cannot transmit a frame to AP 1 (310) during a DPS transition delay time (or, aSIFSTime+aSlotTime+DPS Transition Delay) starting from the time the beacon frame transmission of AP 1 (310) is completed.

[0099] Here, non-AP STA 1 (320) may select a new backoff counter after the TXOP ends and perform a channel access procedure. If the slot boundary at which the backoff counter of non-AP STA 1 (320) reaches 0 ends before the time when AP 1 (310) operates as an LCM, non-AP STA 1 (320) may keep the backoff counter at 0 and wait until the time when AP 1 (310) operates as an LCM. Alternatively, non-AP STA 1 (320) may select a new backoff counter and perform a new channel access procedure so that the slot boundary at which the backoff counter reaches 0 occurs at or after the time when AP 1 (310) operates as an LCM. non-AP STA 1 (320) may start a new TXOP at or after the time when AP 1 (310) operates as an LCM. Here, non-AP STA 1 (320) can transmit an ICF to switch AP 1 (310) from LCM to HCM. Alternatively, it can transmit a frame using communication parameters that match the LCM of AP 1 (310). As described above, non-AP STA 1 (320) can transmit a frame to AP 1 (310) within a TXOP. In the case where AP 1 (310) is a TXOP for transmitting a frame to non-AP STA 1 (320), the TXOP of AP 1 (310) may be terminated before TBTT (or, at a time before PIFS time from TBTT, at a time before aSIFSTime + aSlotTime + DPS Transition Delay time from TBTT, at a time before aSIFSTime + aSlotTime + DPS Transition Delay + PIFS time from TBTT, at a time before DPS Transition Delay time from TBTT, at a time before DPS Transition Delay + PIFS time from TBTT). Here, a certain amount of time from TBTT (e.g.,At a point prior to aSIFSTime+aSlotTime+DPS Transition Delay, aSIFSTime+aSlotTime+DPS Transition Delay + PIFS, DPS transition delay, DPS transition delay + PIFS, PIFS), the non-AP STA 1 (320) or AP 1 (310) terminating the TXOP (or frame transmission, frame exchange) may be an action to ensure at least one or both of the mode transition time (or, mode transition delay) for AP 1 (310) to switch modes from HCM to LCM and sufficient time to detect the channel (e.g., PIFS time for beacon frame transmission).

[0100] The above-described details may be applied in the same way to FIG. 3 as well as FIG. 4 to FIG. 8 below, and may also be applied with modifications depending on the operation of each figure.

[0101] FIG. 4 is a diagram illustrating a method for performing low-latency frame transmission in a wireless LAN network that supports power-saving operations applicable to the present disclosure.

[0102] Referring to FIG. 4, AP 1 (310) and non-AP STA 1 (320) can perform an SCS setup procedure for the QoS parameter negotiation described above. In the SCS negotiation procedure, non-AP STA 1 (320) can send an SCS request frame (401) to AP 1 (310), and AP 1 (310) can send an SCS response frame (402) in response to the SCS request frame (401) of non-AP STA 1 (320), but is not limited thereto, and it may also be possible for AP 1 (310) to send the SCS request frame (401) first. As a result of the SCS negotiation, non-AP STA 1 (320) and AP 1 (310) can set mutual stream classification (or traffic classification), and traffic corresponding to the stream classification can be transmitted using separate EDCA parameters or using a separate EDCA queue. In addition, traffic corresponding to stream classification can be transmitted within the R-TWT SP, which is a low-latency communication section, as described above.

[0103] Additionally, AP 1 (310) may transmit a beacon frame (403). The beacon frame (403) may include at least one of a DPS field or a DPS operation parameter field, and based on this, AP 1 (310) may indicate whether to perform a DPS operation after transmitting the beacon frame. As another example, AP 1 (310) may also transmit a separate frame containing at least one of a DPS field or a DPS operation parameter field, and is not limited to a specific form. The DPS field included in the beacon frame (403) may include a TWT ID indicating an R-TWT SP. Here, AP 1 (310) may indicate whether to operate as HCM, which is one of the operation modes of the DPS operation, in the R-TWT SP, which is a low-latency communication section, as described above.

[0104] Here, the operation described above may be the operation of AP 1 (310) in the R-TWT SP corresponding to the TWT ID. However, AP 1 (310) may be intended to operate as HCM in the periodic communication interval based on all beacon periods (including the R-TWT SP). The non-AP STA 1 (320) may receive a frame containing the DPS field of AP 1 (310), and AP 1 (310) may operate as HCM in the periodic communication interval based on the beacon period. That is, it may not be limited to the R-TWT SP corresponding to the TWT ID.

[0105] Additionally, a communication interval based on a beacon cycle including an R-TWT SP may not be established by the SCS procedure described above. For example, it may be established by considering the traffic conditions of AP 1 (310) or non-AP STA 1 (320) connected to AP 1 (310), and is not limited to a specific form.

[0106] Referring to FIG. 4, it can operate as HCM during a periodic communication interval based on a beacon period (e.g., R-TWT SP and N (N is a natural number) or a beacon period (TBTT) communication interval, etc.). The beacon period communication interval is a time interval up to N TBTT or up to the next TBTT. That is, AP 1 (310) operates as HCM during the periodic communication interval described above, and can switch the operation mode to LCM when the periodic communication interval ends. AP 1 (310) can switch the operation mode to HCM during the periodic communication interval and can receive a low-latency data frame (404) from non-AP STA 1 (320) or transmit a low-latency data frame (405) to non-AP STA 1 (320).

[0107] Here, low-latency data frame transmission (e.g., transmission of uplink data frames, transmission of downlink data frames) may proceed beyond the end time of the periodic communication interval. For example, a TXOP (transmit opportunity), which is a time interval during which at least one of transmitting uplink data frames and receiving downlink data frames can be performed with multiple frames, may exceed the end time of the periodic communication interval based on the beacon period. In the above case, AP 1 (310) may operate as an HCM to complete the frame transmission procedure until the ongoing TXOP is completed (i.e., the exchange of data frames is completed). On the other hand, AP 1 (310) may operate as an LCM after the TXOP is completed (i.e., after the exchange of data frames is completed). The above-described TXOP may have been initiated by AP 1 (310) to perform a frame exchange including a data frame with non-AP STA 1 (320), or the above-described TXOP may have been initiated by AP 1 (310) to perform a frame exchange including a data frame with non-AP STA 1 (320).

[0108] As another example, if the TXOP, which is a time interval in which at least one of transmitting uplink data frames and receiving downlink data frames can be performed in multiple frames, exceeds the end time of the periodic communication interval based on the beacon period, AP 1 (310) can switch the operation mode to LCM when the end time of the periodic communication interval arrives, regardless of the end time of the TXOP.

[0109] As another example, if AP 1 (310) and non-AP STA 1 (320), which is a non-AP STA connected to AP 1 (310), have a TXOP terminated after the current periodic communication period, AP 1 (310) may maintain the HCM operating mode until the periodic communication period (e.g., next TBTT) that is terminated after the TXOP termination time.

[0110] As another example, AP 1 (310) and non-AP STA 1 (320), which is a non-AP STA connected to AP 1 (310), may be required to ensure that the TXOP is terminated within the periodic communication interval.

[0111] Additionally, referring to FIG. 4, non-AP STA 1 (320) can also perform DPS operations similarly to AP 1 (310). When AP 1 (310) performs DPS operations, non-AP STA 1 (320) can synchronize LCM and HCM with AP 1 (310). For example, AP 1 (310) can operate as LCM before receiving ICF in periods other than the R-TWT SP period. Non-AP STA 1 (320) can also operate as LCM until receiving ICF, similar to the above description. Additionally, since AP 1 (310) has instructed non-AP STA 1 (320) to operate as HCM in the R-TWT SP, non-AP STA 1 (320) can also operate as HCM in the R-TWT SP. Here, if at least one of the downlink data frame exchange operation and the uplink data frame exchange operation performed by non-AP STA 1 (320) and AP 1 (310) in the R-TWT SP proceeds beyond the end time of the R-TWT SP, non-AP STA 1 (320) can operate from HCM to LCM after the data frame exchange operation is completed.

[0112] Additionally, STA 2 may be connected to and operate on AP 1 (310). STA 2 may be a STA that performs DPS, but may not be a member of the R-TWT SP, which is the low-latency communication section of AP 1 (310). Therefore, STA 2 may not perform communication operations in the low-latency communication section. Here, AP 1 (310) may operate as LCM until it receives the ICF, and may operate as HCM upon receiving the ICF. Unlike non-AP STA 1 (320), which is a member of the R-TWT SP, STA 2 may not operate as HCM in the R-TWT SP even if AP 1 (310) instructs it to operate as HCM in the R-TWT SP. That is, if STA 2 operates as LCM before the start of the R-TWT SP, STA 2 may continue to operate as LCM during the R-TWT SP unless it receives the ICF.

[0113] FIG. 5 is a diagram illustrating a method for performing low-latency frame transmission in a wireless LAN network that supports power-saving operations applicable to the present disclosure.

[0114] Referring to FIG. 5, AP 1 (310) and non-AP STA 1 (320) may perform an SCS setup procedure for the negotiation of QoS parameters described above. In the SCS negotiation procedure, non-AP STA 1 (320) may send an SCS request frame (401) to AP 1 (310), and AP 1 (310) may send an SCS response frame (402) in response to the SCS request frame (401) of non-AP STA 1 (320), but is not limited thereto, and it may also be possible for AP 1 (310) to send the SCS request frame (401) first. As a result of the SCS negotiation, non-AP STA 1 (320) and AP 1 (310) may set mutual stream classification (or traffic classification), and traffic corresponding to the stream classification may be transmitted using separate EDCA parameters or transmitted using a separate EDCA queue. In addition, traffic corresponding to stream classification can be transmitted within the R-TWT SP, which is a low-latency communication section, as described above.

[0115] Additionally, AP 1 (310) may transmit a beacon frame (403). The beacon frame (403) may include at least one of a DPS field or a DPS operation parameter field, and based on this, AP 1 (310) may indicate whether to perform a DPS operation after transmitting the beacon frame. As another example, AP 1 (310) may also transmit a separate frame containing at least one of a DPS field or a DPS operation parameter field, and is not limited to a specific form. The DPS field included in the beacon frame (403) may include a TWT ID indicating an R-TWT SP. Here, AP 1 (310) may indicate whether to operate as HCM, which is one of the operation modes of the DPS operation, in the R-TWT SP, which is a low-latency communication section, as described above.

[0116] Here, the operation described above may be the operation of AP 1 (310) in the R-TWT SP corresponding to the TWT ID. However, AP 1 (310) may be intended to operate as HCM in the periodic communication interval based on all beacon periods (including the R-TWT SP). The non-AP STA 1 (320) may receive a frame containing the DPS field of AP 1 (310), and AP 1 (310) may operate as HCM in the periodic communication interval based on the beacon period. That is, it may not be limited to the R-TWT SP corresponding to the TWT ID.

[0117] Additionally, a communication interval based on a beacon cycle including an R-TWT SP may not be established by the SCS procedure described above. For example, it may be established by considering the traffic conditions of AP 1 (310) or non-AP STA 1 (320) connected to AP 1 (310), and is not limited to a specific form.

[0118] Referring to FIG. 5, it can operate as HCM during a periodic communication interval based on a beacon period (e.g., R-TWT SP and N (N is a natural number) or a beacon period (TBTT) communication interval, etc.). The beacon period communication interval is a time interval up to N TBTT or up to the next TBTT. That is, AP 1 (310) operates as HCM during the periodic communication interval described above, and can switch the operation mode to LCM when the periodic communication interval ends. AP 1 (310) can switch the operation mode to HCM during the periodic communication interval and can receive low-latency data frames from non-AP STA 1 (320) or transmit low-latency data frames to non-AP STA 1 (320).

[0119] Here, low-latency data frame transmission (e.g., transmission of uplink data frames, transmission of downlink data frames) may proceed beyond the end time of the periodic communication interval. For example, a TXOP (transmit opportunity), which is a time interval during which at least one of transmitting uplink data frames and receiving downlink data frames can be performed with multiple frames, may exceed the end time of the periodic communication interval based on the beacon period. In the above case, AP 1 (310) may operate as an HCM to complete the frame transmission procedure until the ongoing TXOP is completed (i.e., the exchange of data frames is completed). On the other hand, AP 1 (310) may operate as an LCM after the TXOP is completed (i.e., after the exchange of data frames is completed). The above TXOP may be initiated by AP 1 (310) to perform a frame exchange including a data frame with non-AP STA 1 (320), or the above TXOP may be initiated by AP 1 (310) to perform a frame exchange including a data frame with non-AP STA 1 (320).

[0120] As another example, if the TXOP, which is a time interval in which at least one of transmitting uplink data frames and receiving downlink data frames can be performed in multiple frames, exceeds the end time of the periodic communication interval based on the beacon period, AP 1 (310) can switch the operation mode to LCM when the end time of the periodic communication interval arrives, regardless of the end time of the TXOP.

[0121] As another example, if AP 1 (310) and non-AP STA 1 (320), which is a non-AP STA connected to AP 1 (310), have a TXOP terminated after the current periodic communication period, AP 1 (310) may maintain the HCM operating mode until the periodic communication period (e.g., next TBTT) that is terminated after the TXOP termination time.

[0122] As another example, AP 1 (310) and non-AP STA 1 (320), which is a non-AP STA connected to AP 1 (310), may be required to ensure that the TXOP is terminated within the periodic communication interval.

[0123] Here, referring to FIG. 5, AP 1 (310) operates as HCM during the low-latency communication period, but may instruct R-TWT member STAs to wait for the reception of a frame from AP 1 (310) before transmitting a frame during the low-latency communication period of AP 1 (310). AP 1 (310) may transmit a frame containing a DPS field (e.g., a Beacon frame) and operate as LCM. When AP 1 (310) operates as LCM, AP 1 (310) may receive an initial control frame from non-AP STA 1 (320) and other connected STAs during operation. Upon receiving the initial control frame, AP 1 (310) may operate as HCM to perform data transmission and reception, and may return to LCM operation once the data transmission and reception operation is completed. Here, AP 1 (310) operating as LCM may operate as HCM at the start of the R-TWT SP. As described above, AP 1 (310) indicates that it operates as HCM in the R-TWT SP indicated in the DPS field, and based on this, it can operate as HCM at the start of the R-TWT SP. AP 1 (310) can operate as HCM during a periodic communication period based on the beacon period (e.g., R-TWT SP and N (N is a natural number) or beacon period (TBTT) communication period, etc.). That is, AP 1 (310) operates as HCM during the periodic communication period described above, and can switch the operation mode to LCM when the periodic communication period ends.

[0124] Here, it may take time for AP 1 (310) to switch from LCM to HCM in the R-TWT SP. AP 1 (310) may complete the switch from LCM to HCM in advance of the start of the R-TWT SP so that it can operate in HCM from the start of the R-TWT SP. When AP 1 (310) switches the operation mode from LCM to HCM, AP 1 (310) may transmit a frame so that R-TWT member STAs, including non-AP STA 1 (320), can perform transmission in the R-TWT SP. For example, the frame transmitted by AP 1 (310) so that R-TWT member STAs, including non-AP STA 1 (320), can perform transmission in the R-TWT SP may be a data frame or a trigger frame (406). non-AP STA 1 (320) can receive the frame from AP 1 (310). non-AP STA 1 (320) can recognize that AP 1 (310) has completed the transition to HCM within the R-TWT SP and that data communication is possible. non-AP STA 1 (320) can transmit an uplink frame (407) for a response frame or trigger frame for a data frame of AP 1 (310). As another example, non-AP STA 1 (320) can perform a separate channel access operation to transmit an uplink frame. Here, at least one of the uplink data frame and downlink data frame transmitted within the R-TWT SP may be a low-latency data frame corresponding to the traffic classification negotiated in the SCS negotiation procedure.

[0125] Here, the transmission of low-latency data frames (e.g., transmission of uplink data frames, transmission of downlink data frames) may proceed beyond the end time of the R-TWT SP. For example, a TXOP (transmit opportunity), which is a time interval during which at least one of transmitting uplink data frames and receiving downlink data frames can be performed, may exceed the end time of the R-TWT SP based on the beacon period. In the above case, AP 1 (310) may operate as an HCM to complete the frame transmission procedure until the ongoing TXOP is completed (i.e., the exchange of data frames is completed). On the other hand, AP 1 (310) may operate as an LCM after the TXOP is completed (i.e., after the exchange of data frames is completed).

[0126] FIG. 6 is a diagram illustrating a method for performing low-latency frame transmission in a wireless LAN network that supports power-saving operations applicable to the present disclosure.

[0127] Referring to FIG. 6, AP 1 (310) and non-AP STA 1 (320) can perform an SCS setup procedure for the QoS parameter negotiation described above. In the SCS negotiation procedure, non-AP STA 1 (320) can send an SCS request frame (401) to AP 1 (310), and AP 1 (310) can send an SCS response frame (402) in response to the SCS request frame (401) of non-AP STA 1 (320), but is not limited thereto, and it may also be possible for AP 1 (310) to send the SCS request frame (401) first. As a result of the SCS negotiation, non-AP STA 1 (320) and AP 1 (310) can set mutual stream classification (or traffic classification), and traffic corresponding to the stream classification can be transmitted using separate EDCA parameters or using a separate EDCA queue. In addition, traffic corresponding to stream classification can be transmitted within the R-TWT SP, which is a low-latency communication section, as described above.

[0128] Additionally, AP 1 (310) may transmit a beacon frame (403). The beacon frame (403) may include at least one of a DPS field or a DPS operation parameter field, and based on this, AP 1 (310) may indicate whether to perform a DPS operation after transmitting the beacon frame. As another example, AP 1 (310) may also transmit a separate frame containing at least one of a DPS field or a DPS operation parameter field, and is not limited to a specific form. The DPS field included in the beacon frame (403) may include a TWT ID indicating an R-TWT SP. Here, AP 1 (310) may indicate whether to operate as HCM, which is one of the operation modes of the DPS operation, in the R-TWT SP, which is a low-latency communication section, as described above.

[0129] Here, the operation described above may be the operation of AP 1 (310) in the R-TWT SP corresponding to the TWT ID. However, AP 1 (310) may be intended to operate as HCM in the periodic communication interval based on all beacon periods (including the R-TWT SP). The non-AP STA 1 (320) may receive a frame containing the DPS field of AP 1 (310), and AP 1 (310) may operate as HCM in the periodic communication interval based on the beacon period. That is, it may not be limited to the R-TWT SP corresponding to the TWT ID.

[0130] Additionally, a communication interval based on a beacon cycle including an R-TWT SP may not be established by the SCS procedure described above. For example, it may be established by considering the traffic conditions of AP 1 (310) or non-AP STA 1 (320) connected to AP 1 (310), and is not limited to a specific form.

[0131] Referring to FIG. 6, it can operate as HCM during a periodic communication interval based on a beacon period (e.g., R-TWT SP and N (N is a natural number) or a beacon period (TBTT) communication interval, etc.). The beacon period communication interval is a time interval up to N TBTT or up to the next TBTT. That is, AP 1 (310) operates as HCM during the periodic communication interval described above, and can switch the operation mode to LCM when the periodic communication interval ends. AP 1 (310) can switch the operation mode to HCM during the periodic communication interval and can receive low-latency data frames from non-AP STA 1 (320) or transmit low-latency data frames to non-AP STA 1 (320).

[0132] Here, low-latency data frame transmission (e.g., transmission of uplink data frames, transmission of downlink data frames) may proceed beyond the end time of the periodic communication interval. For example, a TXOP (transmit opportunity), which is a time interval during which at least one of transmitting uplink data frames and receiving downlink data frames can be performed with multiple frames, may exceed the end time of the periodic communication interval based on the beacon period. In the above case, AP 1 (310) may operate as an HCM to complete the frame transmission procedure until the ongoing TXOP is completed (i.e., the exchange of data frames is completed). On the other hand, AP 1 (310) may operate as an LCM after the TXOP is completed (i.e., after the exchange of data frames is completed). The above TXOP may be initiated by AP 1 (310) to perform a frame exchange including a data frame with non-AP STA 1 (320), or the above TXOP may be initiated by AP 1 (310) to perform a frame exchange including a data frame with non-AP STA 1 (320).

[0133] As another example, if the TXOP, which is a time interval in which at least one of transmitting uplink data frames and receiving downlink data frames can be performed in multiple frames, exceeds the end time of the periodic communication interval based on the beacon period, AP 1 (310) can switch the operation mode to LCM when the end time of the periodic communication interval arrives, regardless of the end time of the TXOP.

[0134] As another example, if AP 1 (310) and non-AP STA 1 (320), which is a non-AP STA connected to AP 1 (310), have a TXOP terminated after the current periodic communication period, AP 1 (310) may maintain the HCM operating mode until the periodic communication period (e.g., next TBTT) that is terminated after the TXOP termination time.

[0135] As another example, AP 1 (310) and non-AP STA 1 (320), which is a non-AP STA connected to AP 1 (310), may be required to ensure that the TXOP is terminated within the periodic communication interval.

[0136] Here, referring to FIG. 6, AP 1 (310) can transmit a BSR (buffer status report) P (poll) trigger frame (408) within the R-TWT SP. The BSRP trigger frame (408) may be a trigger frame for checking whether there is remaining traffic for member STAs of the R-TWT SP (member STAs including STA 1). STAs that receive the trigger frame from AP 1 (310) may transmit a BSR frame (e.g., a frame containing a BSR field in the form of an A-Control in the HT-Control field of the MAC header of a QoS Null frame) (409). The BSR frame (408) may indicate the queue status of the STAs by AC (access category). If AP 1 (310) determines that there are no more frames to transmit from the member STAs, AP 1 (310) may transmit a frame (410) that terminates the TWT SP (R-TWT SP) early. The frame (410) that terminates the TWT SP early may be a QoS data frame or a QoS Null frame in which the EOSP (end of service period) subfield of the MAC header of the frame is indicated as 1, but is not limited thereto. The frame (410) that terminates the TWT SP early may be transmitted via broadcast or based on a group address that identifies the R-TWT SP member STAs. Alternatively, the frame (408) that terminates the TWT SP early may be transmitted individually to each R-TWT SP member STA (e.g., transmitted via a unicast address). If AP 1 (310) transmits a frame (408) that terminates the TWT SP early, AP 1 (310) can terminate the R-TWT SP and switch from HCM to LCM to operate.Here, AP 1 (310) may set a transition timer instead of immediately operating from HCM to LCM after transmitting a frame that terminates the R-TWT SP. AP 1 (310) may operate by transitioning from HCM to LCM when the transition timer is completed. For example, AP 1 (310) may detect a frame transmission within the transition timer (e.g., AP 1's PHY detects the PHY preamble, AP 1 (310)'s MAC layer receives the PHY-RXSTART.indication primitive from the PHY layer). If the BSS Color field of the PHY preamble detected by AP 1 (310) is not the BSS Color of AP 1 (310), AP 1 (310) may continue the timer and operate by transitioning to LCM when the timer is completed. On the other hand, if the BSS Color field of the PHY preamble detected by AP 1 (310) is the BSS Color of AP 1 (310), AP 1 (310) can know that the detected frame is a frame transmission of the STA connected to AP 1 (310). Therefore, AP 1 (310) can discard the timer and continue to operate as HCM to receive the frame. Additionally, AP 1 (310) can transmit a response frame if the transmission of a response frame for the frame is required.

[0137] As another example, when AP 1 (310) transmits a frame, a PHY-TXSTART.request primitive may occur at the MAC layer of AP 1 (310). In the above case, AP 1 (310) may discard the timer and start the frame switching procedure (transmitting a data frame and receiving a response frame, TXOP). Here, AP 1 (310) may operate in HCM until the frame switching procedure is completed. Also, as an example, non-AP STA 1 (320) may also recognize that the R-TWT SP has terminated early after receiving a frame that terminates the TWT SP of AP 1 (310), and may switch from HCM to LCM to operate.

[0138] FIG. 7 is a diagram illustrating a method for performing low-latency frame transmission in a wireless LAN network that supports power-saving operations applicable to the present disclosure.

[0139] Referring to FIG. 7, AP 1 (310) and non-AP STA 1 (320) may perform an SCS setup procedure for the negotiation of QoS parameters described above. In the SCS negotiation procedure, non-AP STA 1 (320) may send an SCS request frame (401) to AP 1 (310), and AP 1 (310) may send an SCS response frame (402) in response to the SCS request frame (401) of non-AP STA 1 (320), but is not limited thereto, and it may also be possible for AP 1 (310) to send the SCS request frame (401) first. As a result of the SCS negotiation, non-AP STA 1 (320) and AP 1 (310) may set mutual stream classification (or traffic classification), and traffic corresponding to the stream classification may be transmitted using separate EDCA parameters or transmitted using a separate EDCA queue. In addition, traffic corresponding to stream classification can be transmitted within the R-TWT SP, which is a low-latency communication section, as described above.

[0140] Additionally, AP 1 (310) may transmit a beacon frame (403). The beacon frame (403) may include at least one of a DPS field or a DPS operation parameter field, and based on this, AP 1 (310) may indicate whether to perform a DPS operation after transmitting the beacon frame. As another example, AP 1 (310) may also transmit a separate frame containing at least one of a DPS field or a DPS operation parameter field, and is not limited to a specific form. The DPS field included in the beacon frame (403) may include a TWT ID indicating an R-TWT SP. Here, AP 1 (310) may indicate whether to operate as HCM, which is one of the operation modes of the DPS operation, in the R-TWT SP, which is a low-latency communication section, as described above.

[0141] Here, the operation described above may be the operation of AP 1 (310) in the R-TWT SP corresponding to the TWT ID. However, AP 1 (310) may be intended to operate as HCM in the periodic communication interval based on all beacon periods (including the R-TWT SP). The non-AP STA 1 (320) may receive a frame containing the DPS field of AP 1 (310), and AP 1 (310) may operate as HCM in the periodic communication interval based on the beacon period. That is, it may not be limited to the R-TWT SP corresponding to the TWT ID.

[0142] Additionally, a communication interval based on a beacon cycle including an R-TWT SP may not be established by the SCS procedure described above. For example, it may be established by considering the traffic conditions of AP 1 (310) or non-AP STA 1 (320) connected to AP 1 (310), and is not limited to a specific form.

[0143] Referring to FIG. 7, the device can operate as HCM during a periodic communication interval based on the beacon period (e.g., R-TWT SP and N (N is a natural number) or a beacon period (TBTT) communication interval, etc.). The beacon period communication interval is a time interval up to N TBTT or up to the next TBTT. That is, AP 1 (310) operates as HCM during the aforementioned periodic communication interval and can switch the operation mode to LCM when the periodic communication interval ends. AP 1 (310) can switch the operation mode to HCM during the periodic communication interval and can receive low-latency data frames from non-AP STA 1 (320) or transmit low-latency data frames to non-AP STA 1 (320).

[0144] Here, low-latency data frame transmission (e.g., transmission of uplink data frames, transmission of downlink data frames) may proceed beyond the end time of the periodic communication interval. For example, a TXOP (transmit opportunity), which is a time interval during which at least one of transmitting uplink data frames and receiving downlink data frames can be performed with multiple frames, may exceed the end time of the periodic communication interval based on the beacon period. In the above case, AP 1 (310) may operate as an HCM to complete the frame transmission procedure until the ongoing TXOP is completed (i.e., the exchange of data frames is completed). On the other hand, AP 1 (310) may operate as an LCM after the TXOP is completed (i.e., after the exchange of data frames is completed). The above TXOP may be initiated by AP 1 (310) to perform a frame exchange including a data frame with non-AP STA 1 (320), or the above TXOP may be initiated by AP 1 (310) to perform a frame exchange including a data frame with non-AP STA 1 (320).

[0145] As another example, if the TXOP, which is a time interval in which at least one of transmitting uplink data frames and receiving downlink data frames can be performed in multiple frames, exceeds the end time of the periodic communication interval based on the beacon period, AP 1 (310) can switch the operation mode to LCM when the end time of the periodic communication interval arrives, regardless of the end time of the TXOP.

[0146] As another example, if AP 1 (310) and non-AP STA 1 (320), which is a non-AP STA connected to AP 1 (310), have a TXOP terminated after the current periodic communication period, AP 1 (310) may maintain the HCM operating mode until the periodic communication period (e.g., next TBTT) that is terminated after the TXOP termination time.

[0147] As another example, AP 1 (310) and non-AP STA 1 (320), which is a non-AP STA connected to AP 1 (310), may be required to ensure that the TXOP is terminated within the periodic communication interval.

[0148] Here, referring to FIG. 7, non-AP STA 1 (320) may transmit an uplink data frame (411) transmitted within an R-TWT SP containing an indicator that there are no more frames to transmit within the TWT SP (R-TWT SP). For example, the aforementioned indicator may be included in the HT control field of the MAC header of the data frame (411). When AP 1 (310) receives the indicator from non-AP STA 1 (320), AP 1 (310) may transmit a frame (412) that terminates the TWT SP (R-TWT SP) early. The frame (412) that terminates the TWT SP early may be a QoS data frame or a QoS Null frame in which the EOSP (end of service period) subfield of the MAC header of the frame is indicated as 1, but is not limited thereto.

[0149] The frame (412) for early termination of the TWT SP may be transmitted via broadcast or based on a group address that identifies the R-TWT SP member STAs. Alternatively, the frame (412) for early termination of the TWT SP may be transmitted individually to each R-TWT SP member STA (e.g., via a unicast address). When AP 1 (310) transmits the frame for early termination of the TWT SP, AP 1 (310) can terminate the R-TWT SP and operate by switching from HCM to LCM. Here, AP 1 (310) may set a transition timer instead of operating immediately from HCM to LCM after transmitting the frame for early termination of the R-TWT SP. When the transition timer is completed, AP 1 (310) can operate by switching from HCM to LCM. For example, AP 1 (310) can detect a frame transmission within a switching timer (e.g., AP 1's PHY detects a PHY preamble, AP 1's MAC layer receives a PHY-RXSTART.indication primitive from the PHY layer). If the BSS Color field of the PHY preamble detected by AP 1 (310) is not the BSS Color of AP 1 (310), AP 1 (310) can continue the timer and, when the timer is completed, switch to LCM and operate. On the other hand, if the BSS Color field of the PHY preamble detected by AP 1 (310) is the BSS Color of AP 1 (310), AP 1 (310) can know that the detected frame is a frame transmission of the STA connected to AP 1 (310). Therefore, AP 1 (310) can discard the timer and continue to operate in HCM to receive the frame. Additionally, AP 1 (310) can transmit a response frame if transmission of a response frame for a frame is required.

[0150] As another example, when AP 1 (310) transmits a frame, a PHY-TXSTART.request primitive may occur at the MAC layer of AP 1 (310). In the above case, AP 1 (310) may discard the timer and start the frame switching procedure (transmitting a data frame and receiving a response frame, TXOP). Here, AP 1 (310) may operate in HCM until the frame switching procedure is completed. Also, as an example, non-AP STA 1 (320) may also recognize that the R-TWT SP has terminated early after receiving a frame that terminates the TWT SP of AP 1 (310), and may switch from HCM to LCM to operate. As another example, as shown in FIG. 5 above, AP 1 (310) can receive BSRs from member STAs by transmitting a BSRP trigger frame to check the traffic status of the STAs, and AP 1 (310) can terminate the R-TWT SP when there are no more frames for the STAs to transmit.

[0151] FIG. 8 is a diagram illustrating a method for performing low-latency frame transmission in a wireless LAN network that supports power-saving operations applicable to the present disclosure.

[0152] Referring to FIG. 8, AP 1 (310) and non-AP STA 1 (320) may perform an SCS setup procedure for the negotiation of QoS parameters described above. In the SCS negotiation procedure, non-AP STA 1 (320) may send an SCS request frame (401) to AP 1 (310), and AP 1 (310) may send an SCS response frame (402) in response to the SCS request frame (401) of non-AP STA 1 (320), but is not limited thereto, and it may also be possible for AP 1 (310) to send the SCS request frame (401) first. As a result of the SCS negotiation, non-AP STA 1 (320) and AP 1 (310) may set mutual stream classification (or traffic classification), and traffic corresponding to the stream classification may be transmitted using separate EDCA parameters or transmitted using a separate EDCA queue. In addition, traffic corresponding to stream classification can be transmitted within the R-TWT SP, which is a low-latency communication section, as described above.

[0153] Additionally, AP 1 (310) may transmit a beacon frame (403). The beacon frame (403) may include at least one of a DPS field or a DPS operation parameter field, and based on this, AP 1 (310) may indicate whether to perform a DPS operation after transmitting the beacon frame. As another example, AP 1 (310) may also transmit a separate frame containing at least one of a DPS field or a DPS operation parameter field, and is not limited to a specific form. The DPS field included in the beacon frame (403) may include a TWT ID indicating an R-TWT SP. Here, AP 1 (310) may indicate whether to operate as HCM, which is one of the operation modes of the DPS operation, in the R-TWT SP, which is a low-latency communication section, as described above.

[0154] Here, the operation described above may be the operation of AP 1 (310) in the R-TWT SP corresponding to the TWT ID. However, AP 1 (310) may be intended to operate as HCM in the periodic communication interval based on all beacon periods (including the R-TWT SP). The non-AP STA 1 (320) may receive a frame containing the DPS field of AP 1 (310), and AP 1 (310) may operate as HCM in the periodic communication interval based on the beacon period. That is, it may not be limited to the R-TWT SP corresponding to the TWT ID.

[0155] Additionally, a communication interval based on a beacon cycle including an R-TWT SP may not be established by the SCS procedure described above. For example, it may be established by considering the traffic conditions of AP 1 (310) or non-AP STA 1 (320) connected to AP 1 (310), and is not limited to a specific form.

[0156] Referring to FIG. 8, AP 1 (310) operates as an LCM during a periodic communication interval based on a beacon period (e.g., R-TWT SP and N (N is a natural number) or a beacon period (TBTT) communication interval, etc.), and can operate as an HCM when it receives an ICF (413) within the periodic communication interval based on a beacon period. The periodic communication interval based on a beacon period is a time interval up to N TBTT or up to the next TBTT. The DPS field may indicate that AP 1 (310) operates as an LCM until it receives an ICF (413) during the periodic communication interval based on a beacon period (e.g., R-TWT SP). That is, AP 1 (310) may not operate in a mode capable of rapidly transmitting and receiving frames during the periodic communication interval based on a beacon period until it receives the first initial control frame. Here, when AP 1 (310) receives ICF (413) during a periodic communication period based on a beacon period and switches the operating mode to HCM, AP 1 (310) can maintain the operating mode to HCM until the end of the periodic communication period based on a beacon period.

[0157] AP 1 (310) can transmit a frame (e.g., a beacon frame) containing a DPS field and operate as an LCM. While AP 1 (310) is operating as an LCM, it may receive an ICF (413) from non-AP STA 1 (320) and other connected STAs, and upon receiving the ICF (413), it can operate as an HCM to perform data transmission and reception. When the data transmission and reception operation is completed, AP 1 (310) operates as an LCM again.

[0158] That is, AP 1 (310), which was operating as LCM, can operate as LCM at the start and after the start of a periodic communication period based on the beacon period (e.g., R-TWT SP). That is, if the DPS field indicates that it operates as LCM until it receives an ICF from the R-TWT SP, AP 1 (310) operates as LCM at the start and after the start of the R-TWT SP, and can switch to HCM upon receiving the ICF (413). Since non-AP STA 1 (320) can recognize that AP 1 (310) is operating as LCM from the R-TWT SP, it can transmit the ICF (413) to AP 1 (310) once the channel access procedure (e.g., EDCA backoff procedure) is completed. The ICF (413) contains the time for AP 1 (310) to switch from LCM to HCM, which may be included in the padding field. When AP 1 (310) receives ICF (413) from non-AP STA 1 (320), it switches the operating mode from LCM to HCM and can transmit a response frame (414) for ICF. When AP 1 (310) receives the response frame (414) for ICF (413), non-AP STA 1 (320) can transmit a data frame (415) to AP 1 (310).

[0159] When AP 1 (310) receives ICF (413), it switches to HCM within the R-TWT SP interval and operates, and can operate as HCM until the end of the R-TWT SP interval. Additionally, AP 1 (310) can transmit a downlink data frame (416) from the R-TWT SP to non-AP STA 1 (320). At least one of the uplink data frame (415) and downlink data frame (416) transmitted within the R-TWT SP may be a data frame corresponding to the traffic classification negotiated in the SCS negotiation procedure. Here, the transmission of low-latency data frames (e.g., transmission of uplink data frames, transmission of downlink data frames) may proceed beyond the end of the periodic communication interval. For example, a TXOP (transmit opportunity), which is a time interval during which at least one of the transmission of uplink data frames and the reception of downlink data frames can be performed with multiple frames, may exceed the end of the periodic communication interval based on the beacon period. In the above-described case, AP 1 (310) may operate as an HCM to complete the frame transmission procedure until the ongoing TXOP is completed (i.e., the exchange of data frames is completed). On the other hand, AP 1 (310) may operate as an LCM after the TXOP is completed (i.e., after the exchange of data frames is completed). The TXOP may have been initiated by AP 1 (310) to perform a frame exchange containing data frames to non-AP STA 1 (320), or the TXOP may have been initiated by AP 1 (310) to perform a frame exchange containing data frames to non-AP STA 1 (320).

[0160] As another example, if the TXOP, which is a time interval in which at least one of transmitting uplink data frames and receiving downlink data frames can be performed in multiple frames, exceeds the end time of the periodic communication interval based on the beacon period, AP 1 (310) can switch the operation mode to LCM when the end time of the periodic communication interval arrives, regardless of the end time of the TXOP.

[0161] As another example, if AP 1 (310) and non-AP STA 1 (320), which is a non-AP STA connected to AP 1 (310), have a TXOP terminated after the current periodic communication period, AP 1 (310) may maintain the HCM operating mode until the periodic communication period (e.g., next TBTT) that is terminated after the TXOP termination time.

[0162] As another example, AP 1 (310) and non-AP STA 1 (320), which is a non-AP STA connected to AP 1 (310), may be required to ensure that the TXOP is terminated within the periodic communication interval.

[0163] Referring to FIGS. 3 through 8 described above, the communication interval between TWT SP (including R-TWT SP) and N (N is a natural number) or the beacon period (TBTT) may be a periodic communication interval based on the beacon period. As described above, AP 1 (310) may include TWT elements in the beacon frames and other management frames transmitted by AP 1 (310) to indicate the TWT SP. Here, the TWT elements may indicate the period of the TWT SP. That is, in FIGS. 3 through 8, AP 1 (310) may operate as HCM within the periodic time interval, or upon receiving an ICF within the periodic time interval and completing the transition of the operation mode to HCM, may maintain the operation mode as HCM until the periodic time interval ends. The periodic time interval may be a time interval set for each target beacon transmission time (TBTT) of AP 1 (310), a time interval at which TBTT ends, or a separate periodic time interval. Additionally, as an example, the DPS field described above can be replaced with a DPS field (e.g., DPS Operation parameters field) and is not limited to a specific form.

[0164] FIG. 9 is a flowchart illustrating the operation of an AP in a wireless LAN to which the present disclosure applies. Referring to FIG. 9, the AP can transmit a first frame (S910). The AP supports DPS operation, and the first frame may include information related to the AP's DPS operation. Then, the AP can transmit a beacon frame (S920). The beacon frame may include information related to the AP's beacon time period. Then, the AP can communicate with a non-AP STA based on the information related to the beacon time period (S930). Here, if the information related to the DPS operation directs an HCM operation during a periodic time interval corresponding to the information related to the beacon time period, the AP can maintain the HCM during the periodic time interval corresponding to the information related to the beacon time period. Here, the periodic time interval corresponding to the information related to the beacon time period may include at least one of the target beacon transmission time (TBTT) and the R (restricted)-TWT (target wake time) SP (service period).

[0165] Additionally, the periodic time interval is TBTT, and the AP transmits a first frame containing information related to DPS operation that directs HCM operation, and can maintain HCM based on TBTT until the time of transmission of the next beacon frame. For example, the periodic time interval is R-TWT SP, and the AP can maintain HCM during the R-TWT SP interval based on information related to DPS operation that directs HCM operation. Here, when the AP communicates with a non-AP STA during the periodic time interval based on beacon-related time period information, a transmission opportunity (TXOP) for frame exchange with the non-AP STA is established, and if the TXOP exceeds the periodic time interval, the AP can maintain HCM until the TXOP ends. In addition, when the AP communicates with a non-AP STA during a periodic time interval based on beacon-related time period information, a transmission opportunity (TXOP) for frame exchange with the non-AP STA is established, and when the TXOP exceeds the periodic time interval, the AP can switch from HCM to lower capability mode (LCM) and operate regardless of when the TXOP ends when the periodic time interval ends.

[0166] In addition, when the AP communicates with a non-AP STA during a periodic time interval based on beacon-related time period information, a transmission opportunity (TXOP) for frame exchange with the non-AP STA is established, but the TXOP may expire before the end of the periodic time interval.

[0167] Additionally, the AP may operate in either an HCM mode, which enables general transmit and receive operations based on DPS operation, or an LCM mode, in which at least one of the operating bandwidth, the number of operating space streams, and MCS is limited, or in which only the reception of an initial control frame is possible. Additionally, the HCM may be an operating mode without any restrictions other than the upper limit of the wireless LAN terminal's operating capability. For example, when the AP communicates with a non-AP STA during a periodic time interval based on beacon-related time period information, the AP performs frame exchange with the non-AP STA that remains in HCM mode, and when the periodic time interval ends, the AP and the non-AP STA may switch from HCM to LCM. Additionally, when the AP communicates with a non-AP STA during a periodic time interval based on beacon-related time period information, the AP may transmit a trigger frame to the non-AP STA and receive an uplink frame from the non-AP STA based on the trigger frame. Additionally, when the AP communicates with a non-AP STA during a periodic time interval based on beacon-related time period information, the AP may terminate the periodic time interval early after transmitting a periodic time interval early termination frame if there is no data to transmit to the non-AP STA. Additionally, when the AP receives an indicator from the non-AP STA indicating that there is no frame to transmit, the AP may terminate the periodic time interval early after transmitting a periodic time interval early termination frame. Additionally, when the AP communicates with a non-AP STA during a periodic time interval based on beacon-related time period information, the AP may operate as an LCM during the periodic time interval, and when it receives an initial control frame from the non-AP STA while in the LCM, it may switch to and operate as an HCM.

[0168] FIG. 10 is a flowchart illustrating the operation of a non-AP STA in a wireless LAN to which the present disclosure applies. A non-AP STA may receive a first frame (S1010). Here, the AP supports dynamic power saving (DPS) operation, and the first frame may include information related to the AP's DPS operation. Subsequently, the non-AP STA may receive a beacon frame (S1020). Here, the beacon frame includes information related to the AP's beacon time period, and communication with the AP may be performed based on the information related to the beacon time period (S1030). Here, if the information related to the DPS operation indicates a higher capability mode (HCM) operation during a periodic time interval corresponding to the information related to the beacon time period, the AP may maintain the HCM during the periodic time interval corresponding to the information related to the beacon time period. Additionally, the periodic time interval corresponding to the beacon-related time period information may include at least one of the target beacon transmission time (TBTT) and the R (restricted)-TWT (target wake time) SP (service period). Here, the periodic time interval is TBTT, and the AP transmits a first frame containing information related to DPS operation that directs HCM operation, and can maintain HCM until the time of transmission of the next beacon frame based on TBTT. For example, the periodic time interval is R-TWT SP, and the AP can maintain HCM during the R-TWT SP interval based on information related to DPS operation that directs HCM operation.Here, when the AP communicates with a non-AP STA during a periodic time interval based on beacon-related time interval information, a transmission opportunity (TXOP) for frame exchange with the non-AP STA is set, and if the TXOP exceeds the periodic time interval, the AP can maintain HCM until the TXOP ends. Additionally, when the AP communicates with a non-AP STA during a periodic time interval based on beacon-related time interval information, a transmission opportunity (TXOP) for frame exchange with the non-AP STA is set, and if the TXOP exceeds the periodic time interval, the AP can switch from HCM to lower capability mode (LCM) and operate when the periodic time interval ends, regardless of when the TXOP ends.

[0169] In addition, when the AP communicates with a non-AP STA during a periodic time interval based on beacon-related time period information, a transmission opportunity (TXOP) for frame exchange with the non-AP STA is established, but the TXOP may expire before the end of the periodic time interval.

[0170] Additionally, the AP may operate in either an HCM mode, which enables general transmit and receive operations based on DPS operation, or an LCM mode, in which at least one of the operating bandwidth, the number of operating space streams, and MCS is limited, or in which only the reception of an initial control frame is possible. Additionally, the HCM may be an operating mode without any restrictions other than the upper limit of the wireless LAN terminal's operating capability. For example, when the AP communicates with a non-AP STA during a periodic time interval based on beacon-related time period information, the AP performs frame exchange with the non-AP STA that remains in HCM mode, and when the periodic time interval ends, the AP and the non-AP STA may switch from HCM to LCM. Additionally, when the AP communicates with a non-AP STA during a periodic time interval based on beacon-related time period information, the AP may transmit a trigger frame to the non-AP STA and receive an uplink frame from the non-AP STA based on the trigger frame. Additionally, when the AP communicates with a non-AP STA during a periodic time interval based on beacon-related time period information, the AP may terminate the periodic time interval early after transmitting a periodic time interval early termination frame if there is no data to transmit to the non-AP STA. Additionally, when the AP receives an indicator from the non-AP STA indicating that there is no frame to transmit, the AP may terminate the periodic time interval early after transmitting a periodic time interval early termination frame. Additionally, when the AP communicates with a non-AP STA during a periodic time interval based on beacon-related time period information, the AP may operate as an LCM during the periodic time interval, and when it receives an initial control frame from the non-AP STA while in the LCM, it may switch to and operate as an HCM.

[0171] 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.

[0172]

[0173] The above-mentioned matters may also be applied to other systems.

Claims

1. In the method of operation of an access point (AP) in a wireless LAN system, As a step in which the above AP transmits a first frame, the above AP supports dynamic power saving (DPS) operation, and the first frame includes information related to the AP's DPS operation; A step in which the above AP transmits a beacon frame, wherein the beacon frame includes beacon-related time period information of the above AP; and A method of operation comprising the step of communicating with a non-AP STA based on the above-mentioned beacon-related time period information, wherein if the above-mentioned DPS operation-related information directs a higher capability mode (HCM) operation during a periodic time interval corresponding to the above-mentioned beacon-related time period information, the AP maintains the HCM during the periodic time interval corresponding to the above-mentioned beacon-related time period information.

2. In Paragraph 1, A method in which the periodic time interval corresponding to the above beacon-related time period information includes at least one of the target beacon transmission time (TBTT) and the R(restricted)-TWT(target wake time) SP(service period).

3. In Paragraph 2, A method of operation in which the periodic time interval is the TBTT, the AP transmits the first frame containing information related to the DPS operation instructing the HCM operation, and maintains the HCM until the time of transmission of the next beacon frame based on the TBTT.

4. In Paragraph 2, The above periodic time interval is the R-TWT SP, and the AP maintains HCM during the R-TWT SP interval based on the DPS operation-related information indicating the HCM operation.

5. In Paragraph 1, A method of operation in which, when the AP communicates with the non-AP STA during the periodic time interval based on the beacon-related time interval information, a transmission opportunity (TXOP) for frame exchange with the non-AP STA is set, and when the TXOP exceeds the periodic time interval, the AP maintains the HCM until the TXOP ends.

6. In Paragraph 1, A method of operation in which, when the AP communicates with the non-AP STA during the periodic time interval based on the beacon-related time interval information, a transmission opportunity (TXOP) for frame exchange with the non-AP STA is set, and when the TXOP exceeds the periodic time interval, the AP switches from the HCM to a lower capability mode (LCM) and operates when the periodic time interval ends, regardless of the TXOP end time.

7. In Paragraph 1, A method of operation in which, when the AP communicates with the non-AP STA during the periodic time interval based on the beacon-related time period information, a transmission opportunity (TXOP) for frame exchange with the non-AP STA is set, and the TXOP expires before the end of the periodic time interval.

8. In Paragraph 1, A method of operation in which the above AP operates in any one of the following modes based on the above DPS operation: the above HCM, which enables general transmit and receive operations, or a lower capability mode (LCM), in which at least one of the operation bandwidth, the number of operation space streams, and the MCS is limited, or only the reception of an initial control frame is possible.

9. In Paragraph 8, The above HCM is an operation method in which there are no other restrictions other than the upper limit of the wireless LAN terminal's operation capability.

10. In Paragraph 1, When the AP communicates with the non-AP STA during the periodic time interval based on the beacon-related time period information, the AP performs frame exchange with the non-AP STA maintained as the HCM, and A method of operation in which, when the above periodic time interval ends, the AP and the non-AP STA switch from the HCM to the LCM.

11. In Paragraph 1, A method of operation in which, when the AP communicates with the non-AP STA during the periodic time interval based on the beacon-related time period information, the AP transmits a trigger frame to the non-AP STA and receives an uplink frame from the non-AP STA based on the trigger frame.

12. In Paragraph 1, A method of operation in which, when the AP communicates with the non-AP STA during the periodic time interval based on the beacon-related time period information, if there is no data to be transmitted to the non-AP STA, the AP transmits a periodic time interval early termination frame and then terminates the periodic time interval early.

13. In Paragraph 12, A method of operation in which, when the AP receives an indicator from the non-AP STA indicating that there is no frame to transmit, the AP transmits the periodic time interval early termination frame and then terminates the periodic time interval early.

14. In Paragraph 1, A method of operation in which, when the AP communicates with the non-AP STA during the periodic time interval based on the beacon-related time period information, the AP operates as an LCM during the periodic time interval, and when the LCM receives an initial control frame from the non-AP STA, it switches to and operates as an HCM.

15. Regarding an access point (AP) in a wireless LAN system, 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 AP to perform a specific operation by the above-mentioned at least one processor, and The above specific operation is: Transmit a first frame, wherein the AP supports dynamic power saving (DPS) operation, and the first frame includes information related to the AP's DPS operation. Transmit a beacon frame, wherein the beacon frame includes beacon-related time period information of the AP, and The AP includes the step of communicating with a non-AP STA based on the above-mentioned beacon-related time period information, wherein if the above-mentioned DPS operation-related information directs a higher capability mode (HCM) operation during a periodic time interval corresponding to the above-mentioned beacon-related time period information, the AP maintains the HCM during the periodic time interval corresponding to the above-mentioned beacon-related time period information.

16. In a method of operation of a non-access point (AP) STA in a wireless LAN system, As a step in which the above-mentioned non-AP STA receives a first frame, the AP supports dynamic power saving (DPS) operation, and the first frame includes information related to the AP's DPS operation; The step of the above non-AP STA receiving a beacon frame, wherein the beacon frame includes beacon-related time period information of the AP; and A method of operation comprising the step of communicating with the AP based on the above-mentioned beacon-related time period information, wherein if the above-mentioned DPS operation-related information directs a higher capability mode (HCM) operation during a periodic time interval corresponding to the above-mentioned beacon-related time period information, the AP maintains the HCM during the periodic time interval corresponding to the above-mentioned beacon-related time period information.

17. In a non-access point (AP) STA in a wireless LAN system, 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 first frame is received, wherein the AP supports dynamic power saving (DPS) operation, and the first frame includes information related to the AP's DPS operation. A beacon frame is received, wherein the beacon frame includes beacon-related time period information of the AP, and A non-AP STA that communicates with the AP based on the above-mentioned beacon-related time period information, wherein if the above-mentioned DPS operation-related information instructs a higher capability mode (HCM) operation during a periodic time interval corresponding to the above-mentioned beacon-related time period information, the AP maintains the HCM during the periodic time interval corresponding to the above-mentioned beacon-related time period information.

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