Method and apparatus for preemption in wireless LAN system

Abstract

Disclosed are a method and apparatus for preemption in a wireless LAN system according to various embodiments of the present disclosure. A method performed by a first access point (AP) in a wireless local area network (LAN), according to one embodiment of the present disclosure, comprises the steps of: transmitting a first configuration related to allowing preemption of the first AP within a transmission opportunity (TXOP) to be shared by the first AP; identifying data to be transmitted within a shared TXOP that is at least a part of the TXOP of the first AP, wherein the shared TXOP is shared for a second AP; and transmitting the data on the basis of the preemption.

Description

Method and device for preemption in wireless LAN systems

[0001] The present disclosure relates generally to wireless LAN systems, and more particularly to methods and devices for preemption in wireless LAN systems.

[0002] A wireless local area network (WLAN), also known as Wireless Fidelity (Wi-Fi), is a network that allows mobile devices and laptops to access the Internet within a certain distance from an access point (AP). WLAN technology continues to evolve with the rise of the Internet and the expansion of the smartphone market, and WRAN is used to provide high-speed data services to entire cities, including schools, airports, hotels, and offices.

[0003] The WiFi Alliance defines WiFi as a wireless local area network (WLAN) product based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards. IEEE 802.11a and b, published in 1997 and 1999 respectively, are standards that utilize the unlicensed bands at 2.4 GHz and 5 GHz, with IEEE 802.11b providing a transmission rate of 11 Mbps and IEEE 802.11a providing a transmission rate of 54 Mbps. IEEE 802.11g applies orthogonal frequency-division multiplexing (OFDM) at 2.4 GHz to provide a transmission rate of 54 Mbps. IEEE 802.11n uses multiple input multiple output OFDM (MIMO-OFDM) to provide a transmission rate of 300 Mbps using four spatial streams. IEEE 802.11n supports channel bandwidths up to 40 MHz, in which case it provides a transmission rate of 600 Mbps.

[0004] Afterwards, the IEEE 802.11ac standard was introduced, which supports up to 160 MHz bandwidth, 8 spatial streams, and a speed of up to 1 Gbit / s, and IEEE 802.11ax, which provides multi-user MIMO (MU-MIMO) in both uplink and downlink and supports spatial frequency reuse, dynamic fragmentation, etc. Afterwards, 802.11be is being studied, which supports up to 320 ultra-wide channels, multi-link operation, 4kQAM, etc., and aims to theoretically implement a speed of 46 Gbps.

[0005] Various embodiments of the present disclosure can provide a method for transmitting and receiving a signal in a wireless LAN system and a device supporting the same.

[0006] Various embodiments of the present disclosure may provide a method and apparatus for preemption in a wireless LAN system.

[0007] The technical problems to be achieved in various embodiments of the present disclosure are not limited to those mentioned above, and other technical problems not mentioned can be considered by a person having ordinary skill in the art from various embodiments of the present disclosure described below.

[0008] According to one embodiment of the present disclosure, a method performed by a first AP (access point) in a wireless LAN (local access network) can be provided.

[0009] According to one embodiment of the present disclosure, the method may include transmitting a first configuration related to allowing preemption of the first AP within a transmission opportunity (TXOP) to be shared by the first AP; identifying data to be transmitted within a shared TXOP that is at least a portion of the TXOP of the first AP, the shared TXOP being shared for a second AP; and transmitting the data based on the preemption.

[0010] According to one embodiment of the present disclosure, when it is identified that the transmission of the second AP within the shared TXOP starts with a control frame, the step of transmitting the data may include: identifying a transmission section of the continuous transmission of the second AP based on the control frame; when an ACK (acknowledgement) corresponding to the transmission section is identified, transmitting the data after a short inter frame space (SIFS) from the ACK; and when an ACK corresponding to the transmission section is not identified, transmitting the data after a SIFS from the end of the transmission section.

[0011] According to one embodiment of the present disclosure, when the method identifies that the transmission of the second AP within the shared TXOP starts with a data frame, the step of transmitting the data includes: when an ACK corresponding to the data frame is identified, transmitting the data after a SIFS duration from the ACK; and when an ACK corresponding to the data frame is not identified, transmitting the data after a 2*SIFS + ACK duration from an end time of a most recently received data frame before transmission of the data, wherein the ACK duration is determined based on a minimum value among values ​​of a predefined data rate, and the end time of the data frame can be identified based on: a PHY (physical layer) header of the data frame, a MAC (medium access control) header of the data frame, or energy detection.

[0012] According to one embodiment of the present disclosure, the method may include transmitting a second setting related to a maximum transmission duration within the shared TXOP.

[0013] According to one embodiment of the present disclosure, the transmission interval of the continuous transmission of the second AP within the shared TXOP may be limited to less than or equal to the maximum transmission interval.

[0014] According to one embodiment of the present disclosure, the method may include a step of transmitting a first message for sharing the shared TXOP to the second AP.

[0015] According to one embodiment of the present disclosure, the first setting can be transmitted via the first message.

[0016] According to one embodiment of the present disclosure, at least one of the first setting and the second setting may be transmitted via setting information exchange for coordinated time division multiplexing access (C-TDMA) associated with the shared TXOP, wherein the setting information exchange is performed prior to transmission of the first message.

[0017] According to one embodiment of the present disclosure, at least one of the first setting and the second setting may be transmitted via a control message different from the first message, wherein transmission of the control message is performed before transmission of the first message.

[0018] According to one embodiment of the present disclosure, if the shared TXOP has not expired after transmitting the data, no transmission may be performed for a specific time interval after transmitting the data, or a second message may be transmitted to re-share the shared TXOP.

[0019] According to one embodiment of the present disclosure, the specific time interval is greater than SIFS, and the transmission of the second AP within the shared TXOP can be based on the specific time interval.

[0020] According to one embodiment of the present disclosure, a first AP (access point) of a wireless local access network (LAN) may be provided.

[0021] According to one embodiment of the present disclosure, the first AP comprises a transceiver; and a processor coupled to the transceiver, wherein the processor is configured to: transmit a first configuration related to allowing preemption of the first AP within a transmission opportunity (TXOP) by the first AP; identify data to be transmitted within a shared TXOP that is at least a portion of the TXOP of the first AP, the shared TXOP being shared for a second AP; and transmit the data based on the preemption.

[0022] According to one embodiment of the present disclosure, when it is identified that the transmission of the second AP within the shared TXOP starts with a control frame, the processor may be configured to: identify a transmission interval of the continuous transmission of the second AP based on the control frame; when an ACK (acknowledgement) corresponding to the transmission interval is identified, transmit the data after a short inter frame space (SIFS) from the ACK; and when an ACK corresponding to the transmission interval is not identified, transmit the data after a SIFS from the end of the transmission interval.

[0023] According to one embodiment of the present disclosure, when it is identified that the transmission of the second AP within the shared TXOP starts with a data frame, the processor is configured to: when an ACK corresponding to the data frame is identified, transmit the data after a SIFS from the ACK; and when an ACK corresponding to the data frame is not identified, transmit the data after a 2*SIFS + ACK duration from the end time of a most recently received data frame before transmission of the data, wherein the ACK duration is determined based on a minimum value among values ​​of a predefined data rate, and the end time of the data frame can be: identified based on a PHY (physical layer) header of the data frame, identified based on a MAC (medium access control) header of the data frame, or identified based on energy detection.

[0024] According to one embodiment of the present disclosure, the processor may be configured to transmit a second setting related to a maximum transmission duration within the shared TXOP.

[0025] According to one embodiment of the present disclosure, the transmission interval of the continuous transmission of the second AP within the shared TXOP may be limited to less than or equal to the maximum transmission interval.

[0026] According to one embodiment of the present disclosure, the processor may be configured to transmit a first message for sharing the shared TXOP to the second AP.

[0027] According to one embodiment of the present disclosure, the first setting can be transmitted via the first message.

[0028] According to one embodiment of the present disclosure, at least one of the first setting and the second setting may be transmitted via setting information exchange for coordinated time division multiplexing access (C-TDMA) associated with the shared TXOP, wherein the setting information exchange is performed prior to transmission of the first message.

[0029] According to one embodiment of the present disclosure, at least one of the first setting and the second setting may be transmitted via a control message different from the first message, wherein transmission of the control message is performed before transmission of the first message.

[0030] According to one embodiment of the present disclosure, if the shared TXOP has not expired after transmitting the data, no transmission may be performed for a specific time interval after transmitting the data, or a second message may be transmitted to re-share the shared TXOP.

[0031] According to one embodiment of the present disclosure, the specific time interval is greater than SIFS, and the transmission of the second AP within the shared TXOP can be based on the specific time interval.

[0032] According to one embodiment of the present disclosure, a method performed by a second AP (access point) in a wireless LAN (local access network) can be provided.

[0033] According to one embodiment of the present disclosure, the method includes the steps of receiving a first configuration related to allowing preemption of the first AP within a transmission opportunity (TXOP) to be shared from the first AP; identifying a shared TXOP that is at least a portion of the TXOP of the first AP; and performing transmission within the shared TXOP based on a specific time interval, wherein the specific time interval can be greater than a short inter frame space (SIFS).

[0034] According to one embodiment of the present disclosure, the method may include receiving a second setting related to a maximum transmission duration within the shared TXOP.

[0035] According to one embodiment of the present disclosure, the transmission interval of the continuous transmission of the second AP within the shared TXOP may be limited to less than or equal to the maximum transmission interval.

[0036] According to one embodiment of the present disclosure, the method may include receiving a first message for the shared TXOP from the first AP.

[0037] According to one embodiment of the present disclosure, the first setting can be received via the first message.

[0038] According to one embodiment of the present disclosure, at least one of the first setting and the second setting may be received through setting information exchange for coordinated time division multiplexing access (C-TDMA) related to the shared TXOP, wherein the setting information exchange is performed before receiving the first message.

[0039] According to one embodiment of the present disclosure, at least one of the first setting and the second setting may be received via a control message different from the first message, wherein reception of the control message is performed prior to reception of the first message.

[0040] According to one embodiment of the present disclosure, the method may include a step of performing transmission based on the specific time interval within the remaining time of the shared TXOP, if the shared TXOP has not expired after transmission of data based on the preemption of the first AP is identified within the specific time interval.

[0041] According to one embodiment of the present disclosure, the shared TXOP not expiring may be related to the fact that no transmission of data from the first AP is identified during the specific time interval after the transmission of data based on the preemption, or a second message is received indicating that the shared TXOP is re-shared.

[0042] According to one embodiment of the present disclosure, a second AP (access point) may be provided in a wireless local access network (LAN).

[0043] According to one embodiment of the present disclosure, the second AP comprises a transceiver; and a processor coupled to the transceiver, wherein the processor is configured to: receive a first configuration related to allowing preemption of the first AP within a transmission opportunity (TXOP) to be shared from the first AP; identify a shared TXOP that is at least a portion of the TXOP of the first AP; and perform transmission within the shared TXOP based on a specific time interval, wherein the specific time interval can be greater than a short inter frame space (SIFS).

[0044] According to one embodiment of the present disclosure, the processor may be configured to receive a second setting relating to a maximum transmission duration within the shared TXOP.

[0045] According to one embodiment of the present disclosure, the transmission interval of the continuous transmission of the second AP within the shared TXOP may be limited to less than or equal to the maximum transmission interval.

[0046] According to one embodiment of the present disclosure, the processor may be configured to receive a first message for the shared TXOP from the first AP.

[0047] According to one embodiment of the present disclosure, the first setting may be received via the first message, or at least one of the first setting and the second setting may be received via exchange of setting information for coordinated time division multiplexing access (C-TDMA) related to the shared TXOP, wherein the exchange of setting information is performed before reception of the first message, or at least one of the first setting and the second setting may be received via a control message different from the first message, wherein reception of the control message is performed before reception of the first message.

[0048] According to one embodiment of the present disclosure, the processor may be configured to perform transmission based on the specific time interval within the remaining time of the shared TXOP, if the shared TXOP has not expired after the transmission of data based on the preemption of the first AP is identified within the specific time interval.

[0049] According to one embodiment of the present disclosure, the shared TXOP not expiring may be related to the fact that no transmission of data from the first AP is identified during the specific time interval after the transmission of data based on the preemption, or a second message is received indicating that the shared TXOP is re-shared.

[0050] The various embodiments of the present disclosure described above are only some of the preferred embodiments of the present disclosure, and various embodiments reflecting the technical features of the various embodiments of the present disclosure can be derived and understood by a person having ordinary skill in the art based on the detailed description to be described below.

[0051] Various embodiments of the present disclosure can provide a method for transmitting and receiving a signal in a wireless LAN system and a device supporting the same.

[0052] Various embodiments of the present disclosure may provide a method and apparatus for preemption in a wireless LAN system.

[0053] The effects that can be obtained from various embodiments of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by a person having ordinary skill in the art based on the detailed description below.

[0054] The accompanying drawings are intended to aid in understanding various embodiments of the present disclosure, and provide various embodiments of the present disclosure together with detailed descriptions. However, the technical features of the various embodiments of the present disclosure are not limited to specific drawings, and the features disclosed in each drawing may be combined with each other to form new embodiments. Reference numerals in each drawing represent structural elements.

[0055] FIG. 1 is a diagram illustrating an example of a wireless communication network to which various embodiments of the present disclosure can be applied.

[0056] FIG. 2 is a diagram illustrating an example of the structure of an electronic device performing WLAN connection to which various embodiments of the present disclosure are applicable.

[0057] FIG. 3 is a diagram illustrating an example of a link setup process of a general wireless LAN to which various embodiments of the present disclosure are applicable.

[0058] FIG. 4 is a diagram illustrating an example of a hidden node and an exposed node to which various embodiments of the present disclosure are applicable, and an example of an RTS and a CTS for solving the problem of the hidden node and the exposed node.

[0059] FIG. 5 is a diagram illustrating an example of a frame structure used in an IEEE 802.11 system to which various embodiments of the present disclosure are applicable.

[0060] FIG. 6 is a diagram illustrating an example of NAV settings to which various embodiments of the present disclosure can be applied.

[0061] FIG. 7 is a diagram illustrating an example of a TXOP to which various embodiments of the present disclosure can be applied.

[0062] FIG. 8 is a diagram illustrating an example of an operation for coordinated time division multiplexing access (C-TDMA) to which various embodiments of the present disclosure are applicable.

[0063] FIG. 9 is a diagram illustrating an example of multiple MP (M-AP) TXOP sharing to which various embodiments of the present disclosure are applicable.

[0064] FIG. 10 illustrates an example of a low-latency (LL) traffic transmission and reception process in C-TDMA to which various embodiments of the present disclosure are applicable.

[0065] FIG. 11 illustrates an example of preemption operation in C-TDMA to which various embodiments of the present disclosure are applicable.

[0066] FIG. 12 illustrates an example of preemption operation in C-TDMA to which various embodiments of the present disclosure are applicable.

[0067] FIG. 13a is a diagram illustrating an example of a preemption operation in C-TDMA according to one embodiment of the present disclosure.

[0068] FIG. 13b is a diagram illustrating an example of a preemption operation in C-TDMA according to one embodiment of the present disclosure.

[0069] FIG. 14 is a diagram for explaining an example of a method for transmitting and receiving setup information for preemption operation of a sharing AP in C-TDMA according to one embodiment of the present disclosure.

[0070] FIG. 15 is a diagram for explaining an example of a method for transmitting and receiving setup information for preemption operation of a sharing AP in C-TDMA according to one embodiment of the present disclosure.

[0071] FIG. 16 is a diagram for explaining an example of a method for transmitting and receiving setup information for preemption operation of a sharing AP in C-TDMA according to one embodiment of the present disclosure.

[0072] FIG. 17 is a diagram for explaining an example of a method for transmitting and receiving setup information for preemption operation of a sharing AP in C-TDMA according to one embodiment of the present disclosure.

[0073] FIG. 18 is a diagram for explaining an example of a method for transmitting and receiving setup information for preemption operation of a sharing AP in C-TDMA according to one embodiment of the present disclosure.

[0074] FIG. 19 illustrates an example of the operation of a sharing AP according to one embodiment of the present disclosure.

[0075] FIG. 20 illustrates an example of the operation of a shared AP according to one embodiment of the present disclosure.

[0076] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings.

[0077] In describing the embodiments, descriptions of technical details that are well known in the technical field to which the present disclosure pertains and are not directly related to the present disclosure will be omitted. This is to avoid obscuring the gist of the present disclosure by omitting unnecessary explanations and to convey the gist more clearly.

[0078] For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted. Furthermore, the dimensions of each component do not entirely reflect its actual size. Identical or corresponding components in each drawing are assigned the same reference numbers.

[0079] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. The embodiments of the present disclosure are provided only to ensure that the present disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

[0080] At this time, it will be understood that each block of the processing flowchart drawings and combinations of the flowchart drawings can be performed by computer program instructions. These computer program instructions can be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, so that the instructions executed by the processor of the computer or other programmable data processing equipment create a means for performing the functions described in the flowchart block(s). These computer program instructions can also be stored in a computer-available or computer-readable memory that can direct a computer or other programmable data processing equipment to implement the functions in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can also produce a manufactured item that includes an instruction means for performing the functions described in the flowchart block(s).

[0081] Since the computer program instructions may be installed on a computer or other programmable data processing device, a series of operational steps may be performed on the computer or other programmable data processing device to create a computer-executable process, so that the instructions that cause the computer or other programmable data processing device to perform the steps for performing the functions described in the flowchart block(s) may also be able to provide steps for performing the functions described in the flowchart block(s).

[0082] Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for performing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions described in the blocks may occur out of order. For example, two blocks depicted in succession may actually be executed substantially concurrently, or the blocks may sometimes be executed in reverse order, depending on their respective functions.

[0083] Here, the term '~ unit' used in this embodiment means software or hardware components such as FPGA (field programmable gate array) or ASIC (application specific integrated circuit), and the '~ unit' performs certain roles. However, the '~ unit' is not limited to software or hardware. The '~ unit' may be configured to be on an addressable storage medium and may be configured to play one or more processors. Accordingly, according to some embodiments, the '~ unit' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. Additionally, the components and '~parts' may be implemented to activate one or more CPUs within the device or secure multimedia card. Furthermore, according to some embodiments, the '~parts' may include one or more processors.

[0084] The exemplary embodiments are described below solely for simplicity with respect to wireless LAN systems. It should be understood that the exemplary embodiments are equally applicable to other wireless networks (e.g., cellular networks, pico-networks, femto-networks, satellite networks), as well as systems that utilize signals of one or more wired standards or protocols (e.g., Ethernet and / or HomePlug, PLC standards). As used herein, the terms WLAN and Wi-Fi® may include communications governed by the IEEE 802.11 family of standards, BLUETOOTH®, HiperLAN (a set of wireless standards primarily used in Europe and comparable to the IEEE 802.11 standards), and other technologies with relatively short radio ranges. Accordingly, the terms WLAN and WiFi may be used interchangeably herein. Additionally, while described below with respect to an infrastructure WLAN system including one or more APs and a plurality of wireless stations (STAs), the exemplary embodiments are equally applicable to other WLAN systems including, for example, multiple WLANs, peer-to-peer (or independent basic service set) systems, Wi-Fi Direct systems, and / or hotspots.

[0085] Additionally, while the present disclosure describes the exchange of data frames between wireless devices, the exemplary embodiments may be applied to the exchange of any data unit, packet, and / or frame between wireless devices. Thus, the term frame may include any frame, packet, or data unit, such as, for example, protocol data units (PDUs), media access control (MAC) protocol data units (MPDUs), and physical layer convergence procedure (PLCP) protocol data units (PPDUs). The term A-MPDU may mean aggregated MPDUs. A wireless local area network, or WLAN network, below may be a network implementing at least one of the IEEE 802.11 family of wireless communication protocol standards, such as those defined by the IEEE 802.11-2016 standard or amendments thereto (including, but not limited to, 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be).

[0086] In the following description, numerous specific details are set forth, such as examples of specific components, circuits, and processes, to provide a thorough understanding of the present disclosure. The term "connected," as used herein, means directly connected or connected via one or more intervening components or circuits. The term "connected AP" refers to an access point with which a given wireless station is currently associated and / or connected (e.g., there is an established communications channel or link between the access point and the given wireless station). Furthermore, in the following description and for purposes of explanation, specific nomenclature is set forth to provide a thorough understanding of the exemplary embodiments. However, it will be apparent to one skilled in the art that such specific details may not be necessary to practice the exemplary embodiments. In other instances, well-known circuits and devices are shown in block diagram form to avoid obscuring the present disclosure.

[0087] The operating principles of the present disclosure are described in detail below with reference to the attached drawings. In the following description of the present disclosure, detailed descriptions of related known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Furthermore, the terms described below are defined based on the functions of the present disclosure and may vary depending on the intent or custom of the user or operator. Therefore, their definitions should be based on the overall content of this specification.

[0088] FIG. 1 is a diagram illustrating an example of a wireless communication network to which various embodiments of the present disclosure can be applied.

[0089] The wireless communication network (100) may be an example of a wireless local area network (LAN), such as a Wi-Fi network. The wireless communication network (100) may include a plurality of wireless communication devices, such as an AP (102) and a plurality of STAs (stations, 104). Although only one AP (102) is illustrated, the wireless communication network (100) may also include a plurality of APs (102).

[0090] An STA is a logical entity that includes a MAC and a physical layer interface to a wireless medium, and includes an AP and a non-AP STA (Non-AP station). Among the STAs, a portable terminal operated by a user is a Non-AP STA, and when simply referred to as an STA, it also refers to a Non-AP STA. Hereinafter, an STA may refer to a non-AP STA. Each of the STAs (104) may be referred to as a terminal or a device. The term 'terminal' or 'device' used in this specification may be referred to as a mobile station (MS), user equipment (UE), user terminal (UT), wireless terminal, access terminal (AT), terminal, subscriber unit, subscriber station (SS), wireless device, wireless communication device, wireless transmit / receive unit (WTRU), mobile node, mobile, or other terms. Various embodiments of the terminal may include a cellular telephone, a smart phone having wireless communication capabilities, a personal digital assistant (PDA) having wireless communication capabilities, a wireless modem, a portable computer having wireless communication capabilities, a photographic device such as a digital camera having wireless communication capabilities, a gaming device having wireless communication capabilities, a music storage and playback appliance having wireless communication capabilities, an Internet appliance capable of wireless Internet access and browsing, as well as portable units or terminals incorporating combinations of such functions. In addition, the terminal may include, but is not limited to, a machine-to-machine (M2M) terminal, a machine type communication (MTC) terminal / device. In the present specification, the terminal may also be referred to as an electronic device or simply a device.

[0091] An AP (102) is an entity that provides access to a distribution system (DS) via a wireless medium to its associated STAs. An AP may also be called a centralized controller, a base station (BS), a Node-B, a base transceiver system (BTS), or a site controller.

[0092] An exemplary coverage area (106) of an AP (102) that may represent a basic service area (BSA) of a wireless communication network (100) is illustrated. The AP (102) periodically broadcasts beacon frames (beacon frames may be used interchangeably with beacon) containing a basic service set identifier (BSSID) to enable any STAs (104) within the wireless range of the AP (102) to associate or re-associate with the AP (102) and establish or maintain a separate communication link (108) (or may be referred to as a Wi-Fi link) with the AP (102). The AP (102) may provide access to external networks for various STAs (104) within the WLAN via the separate communication links (108).

[0093] A single AP (102) and an associated set of STAs (104) may be referred to as a basic service set (BSS) managed by the individual AP (102). The BSS may be identified to users by a service set identifier (SSID), as well as to other devices by the BSSID, which may be the MAC address of the AP (102).

[0094] BSS can be categorized into infrastructure BSS and independent BSS (IBSS). The BSS illustrated in Figure 1 is an IBSS, but an infrastructure BSS (not shown) can also be established. An infrastructure BSS includes one or more STAs and an AP. In principle, communication between non-AP STAs in an infrastructure BSS occurs via the AP. However, if a direct link is established between non-AP STAs, direct communication between non-AP STAs is also possible.

[0095] Multiple infrastructure BSSs can be interconnected via a DS. Multiple BSSs connected via a DS are called an extended service set (ESS). STAs within an ESS can communicate with each other, and within the same ESS, STAs can seamlessly move from one BSS to another while maintaining seamless communication.

[0096] A DS is a mechanism that connects multiple APs. It doesn't necessarily have to be a network, and there are no restrictions on its form as long as it can provide a certain distribution service. For example, a DS could be a wireless network, such as a mesh network, or a physical structure that connects APs.

[0097] Additionally, the AP (102) and the STA (104) may be referred to as AP-MLD (access point multi-link device) and STA-MDL, respectively. This may mean that the AP and the STA can support multi-link operation.

[0098] Below is an example of a hierarchical structure according to the 802.11 standard.

[0099] The 802.11 standard document is developing the MAC and PHY protocols corresponding to Wi-Fi wireless access technology. The data link layer (DLL) includes the MAC sublayer, which is responsible for media access control, and receives packets from the upper layer, 802.1X Port Filtering, through the MAC_SAP interface, and configures them into IEEE 802.11 MAC frames and transmits them to the physical layer. The physical layer includes the PLCP (physical layer convergence procedure) sublayer and the PDM (physical medium dependent) sublayer, and the PLCP sublayer is responsible for configuring the IEEE 802.11 MAC frame configured in the MAC sublayer into a PLCP frame. The PLCP frame is then transmitted to the opposite terminal through the PMD sublayer.

[0100] Various management frames that manage Wi-Fi wireless access are not transmitted at the upper layer of 802.1X. These management frames are transmitted as requests and responses between the SMEs (station management entities) located within each terminal. The SME is a layer-independent entity that may exist within a separate management plane or may appear to be off to the side. For example, if an AP wants to form a BSS, the AP instructs the transmission of a beacon through the MLME_SAP interface, namely, the MLME-START.reques and MLME-START.confirm primitives. If an STA wants to associate with the AP, the STA instructs the transmission of an association Request / Response frame through the MLME-ASSOCIATE.request, MLME-ASSOCIATE.response, MLME-ASSOCIATE.confirm, and MLME-ASSOCIATE.indication primitives. Meanwhile, if SME wants to set operating parameter values ​​related to the physical layer, it can set various physical layer parameter values ​​through the PLCP_SAP interface.

[0101] FIG. 2 is a diagram illustrating an example of the structure of an electronic device performing WLAN connection to which various embodiments of the present disclosure are applicable.

[0102] Referring to FIG. 2, an electronic device (200) may be connected to an AP (210), and the electronic device (200) may include a processor (230) and a communication module (220). The electronic device (200) may be the STA (104) of FIG. 1, in which case the electronic device (200) may be connected to the AP (210) as illustrated. Alternatively, the electronic device (200) may be the AP (102) of FIG. 1, in which case the electronic device may be connected to the STA (104) and / or another AP as illustrated in FIG. 1.

[0103] The communication module (220) can receive a communication signal from the outside or transmit a communication signal to the outside based on a Wi-Fi communication method (for example, IEEE Std 802.11TM). For example, the communication module (220) can operate based on IEEE 802.11ac, 802.11ax, 802.11be, or 802.11bn among Wi-Fi communication methods, and in particular, IEEE 802.11be or 802.11bn has improved performance by supporting a wider bandwidth, higher data throughput, and shorter delay time compared to IEEE 802.11ax.

[0104] The communication module (220) may include a transceiver (224) for transmitting and receiving data with an external device and a communication processor (222) (e.g., a communication processor (not shown) or a short-range wireless communication module (e.g., a Wi-Fi chipset)). According to various embodiments, the communication module (220) may further include a memory.

[0105] According to various embodiments, the transceiver (224) may convert a baseband transmit signal into a wireless signal or may convert a received wireless signal into a baseband receive signal.

[0106] According to various embodiments, the communication module (220) may further include, in addition to the transceiver (224) and the communication processor (222), components for OFDM or OFDMA (orthogonal frequency division multiple access), for example, a modulator, a digital-analog converter (D / A converter), a frequency converter, an A / D converter, an amplifier, and / or a demodulator.

[0107] Although not shown, according to various embodiments, the electronic device (200) may include at least one antenna module that is electrically connected to the communication module of the AP (210) and supports a communication protocol and / or frequency band supported by the communication module of the AP (210).

[0108] The communication processor (222) may control the transceiver (224) to form a communication connection with the AP (210). For example, the communication connection may include a Wi-Fi network. For example, the communication processor (222) may control the transceiver (224) to form a wireless connection with the AP (200) using a 2.4 GHz, 5 GHz, or 6 GHz band WLAN standard such as IEEE 802.11ac, 802.11ax, 802.11be, or 802.11bn. Alternatively, the communication processor (222) may control the transceiver (191) to form a wireless connection with the AP (210) using a 60 GHz band WLAN standard such as IEEE 802.11ad or 802.11ay. Additionally, a method of communicating between an electronic device (200) and an AP (210) using the WLAN standard may be referred to as a communication method based on the STA mode.

[0109] According to various embodiments, the processor (230) may include an application processor. The processor (230) may perform a specified operation of the electronic device (200) or control other hardware (e.g., a communication module (220)) to perform a specified operation.

[0110] According to various embodiments, the AP (210) may support an operation of transmitting packets to an external network and / or an operation of the plurality of electronic devices receiving packets from an external network based on a connection between a plurality of electronic devices (e.g., the electronic device (200)) and an external network (e.g., the Internet, an external LAN, or a cellular network).

[0111] For example, the AP (210) may be a wireless router. The AP (210) may be a dedicated wireless router or a general-purpose device supporting mobile hotspot functionality, and there are no limitations on its implementation. For example, the AP (210) may include the same components as the electronic device (200), such as a processor and / or a communication module. Furthermore, the AP (210) may transmit and receive data to and from an external device, such as a server. For example, the AP (210) may transmit at least a portion of the data received from the server to the electronic device (200).

[0112] If the electronic device (200) of FIG. 2 corresponds to the AP (102), the electronic device (200) may include a separate communication module for connection with an external network, although not shown. This communication module may be controlled by the processor (230) or by a separate processor. The separate communication module may include a transceiver and a processor, and may also include memory. In addition, the electronic device (200) may include a separate antenna module or wired connection device for connection with an external network.

[0113] FIG. 3 is a diagram illustrating an example of a link setup process of a general wireless LAN to which various embodiments of the present disclosure are applicable.

[0114] For an STA to set up a link and transmit and receive data on a network, it must first discover the network, perform authentication, establish an association, and complete security authentication procedures. The link setup process can also be referred to as the session initiation process or session setup process. Furthermore, the discovery, authentication, association, and security setup processes of the link setup process can be collectively referred to as the association process.

[0115] Referring to FIG. 3, an STA (300) can perform a network discovery operation. The network discovery operation may include a scanning operation of the STA (300). That is, in order for the STA (300) to access a network, it must search for a network it can participate in. Before joining a wireless network, the STA (300) must identify a compatible network. The process of identifying networks existing in a specific area is called scanning.

[0116] There are two types of scanning methods: active scanning and passive scanning. In active scanning, an STA (300) performing scanning transmits a probe request frame (322) to search for APs in the vicinity while moving between channels and waits for a response. A responder transmits a probe response frame (324) to the STA that transmitted the probe request frame in response to the probe request frame. Here, the responder may be an AP or STA that last transmitted a beacon frame in the BSS of the channel being scanned. In FIG. 3, an example of a BSS that becomes a responder is shown because an AP (310) transmits a beacon frame (320), and in an IBSS, STAs within the IBSS take turns transmitting beacon frames, so the responder is not constant. For example, if an STA transmits a probe request frame on channel 1 and receives a probe response frame on channel 1, the STA can store BSS-related information included in the received probe response frame and move to the next channel to perform scanning in the same manner.

[0117] The scanning operation can also be performed in a passive scanning manner. In passive scanning, the STA performing the scanning moves through channels and detects beacon frames. A beacon frame is one of the management frames in IEEE 802.11, and is periodically transmitted to announce the presence of a wireless network and to enable the STA performing the scanning to find the wireless network and participate in the wireless network. FIG. 3 illustrates an example of a BSS in which an AP (310) periodically transmits a beacon frame (320) to an STA (300), and in an IBSS, STAs within the IBSS take turns transmitting beacon frames. When the STA performing the scanning receives a beacon frame, it stores information about the BSS included in the beacon frame and moves to another channel, recording the beacon frame information on each channel. Comparing active and passive scanning, active scanning has the advantage of lower delay and power consumption than passive scanning.

[0118] After the STA (300) discovers the network, an authentication process may be performed. This authentication process may be referred to as the first authentication process to clearly distinguish it from the security setup operation (350) described below. The authentication process includes a process in which the STA (300) transmits an authentication request frame (330) to the AP (310), and in response, the AP (310) transmits an authentication response frame (332) to the STA (300). The authentication frame used for the authentication request / response corresponds to a management frame.

[0119] The authentication frame may include information such as an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a Robust Security Network (RSN), and a Finite Cyclic Group. These are just some examples of information that may be included in an authentication request / response frame, and may be replaced with other information or include additional information.

[0120] The AP (310) may determine whether to allow authentication for the STA based on information included in the received authentication request frame. The AP (310) may provide the result of the authentication process to the STA (300) via an authentication response frame.

[0121] After the STA is successfully authenticated, an association process can be performed. The association process includes a process in which the STA (300) transmits an association request frame (340) to the AP (310), and in response, the AP (310) transmits an association response frame (342) to the STA (300).

[0122] For example, the association request frame may include information related to various capabilities, such as beacon listen interval, SSID, supported rates, supported channels, robust security network (RSN), mobility domain, supported operating classes, traffic indication map broadcast request, and interworking service capabilities.

[0123] For example, the association response frame may include information related to various capabilities, status codes, association ID (AID), supported rates, enhanced distributed channel access (EDCA) parameter sets, received channel power indicator (RCPI), received signal to noise indicator (RSNI), mobility domains, timeout interval (association comeback time), overlapping BSS scan parameters, TIM broadcast response, QoS maps, etc.

[0124] These are just some examples of information that may be included in a request / response frame, and may be replaced by other information or include additional information.

[0125] Although not shown, after the STA successfully associates with the network, a security setup process may be performed. The security setup process may be referred to as an authentication process via a robust security network association (RSNA) request / response, the authentication process (330) may be referred to as a first authentication process, and the security setup process may also be referred to as an authentication process.

[0126] The security setup process may include, for example, a private key setup process through a four-way handshaking using an extensible authentication protocol over LAN (EAPOL) frame, or may be performed according to a security method not defined in the IEEE 802.11 standard.

[0127] Below we describe the media access control protocol provided by 802.11.

[0128] In wireless LAN systems based on IEEE 802.11, the basic access mechanism of MAC is based on the distributed coordination function (DCF) that utilizes the carrier sense multiple access with collision avoidance (CSMA / CA) method. There are two methods for detecting carriers in DCF: physical carrier sense and virtual carrier sense. Physical carrier sense is a method in which the physical layer detects the channel status and notifies the MAC layer, and virtual carrier sense is a method in which the channel occupancy time is broadcast to neighboring stations to reserve the channel in advance. An STA or AP that has secured a transmission channel records and transmits this channel occupancy time within the RTS or / and CTS or data frame. Other STAs that receive this determine that the channel is busy during this time and do not compete for the channel, thereby avoiding collisions.

[0129] The physical carrier sensing method basically adopts a listen-before-talk access mechanism, and according to this type of access mechanism, the AP and / or STA can perform a clear channel assessment (CCA) to sense the wireless channel or carrier or medium for a predetermined time period before starting transmission. The predetermined time period is called an inter frame space (IFS) and can vary depending on the priority of the traffic to be transmitted. That is, the priority can be determined by the length of the time period, and the higher the priority packet, the shorter the time period can be.

[0130] The above IFS may include a short IFS (SIFS), a priority IFS (PIFS, a point coordination function (PCF) IFS), a distributed (coordination function) IFS (DIFS), an arbitration IFS (AIFS), etc. The SIFS is the shortest time interval and may be mainly used as a waiting time for control information. The PIFS is a medium-length time interval and may be for a packet with a medium priority (PIFS = SIFS+1 slot time). The DIFS is the longest time interval compared to the SIFS and PIFS, has a low priority, and may be mainly used as a waiting time for checking whether a channel is in use (DIFS=SIFS+2 slot time). That is, for example, an STA that wishes to perform transmission may listen to whether a channel is in use (or detect the channel) during the DIFS period.

[0131] Based on the sensing result, if the medium is determined to be in an idle state, the AP and / or STA initiate frame transmission through the medium. On the other hand, if the medium is detected to be in an occupied state, the AP and / or STA may not initiate its own transmission, but may wait for a delay period (e.g., a random backoff period) for medium access before attempting frame transmission. By applying a random backoff period, multiple STAs are expected to attempt frame transmission after waiting for different periods of time, thereby minimizing collisions.

[0132] However, since this DCF method does not consider the priority between STAs, it has a problem in that it is difficult to support various types of data transmission and QoS (Quality of Service), so the hybrid coordination function (HCF) was introduced. HCF is based on the DCF and the point coordination function (PCF). PCF is a polling-based synchronous access method that periodically polls all receiving APs and / or STAs so that they can receive data frames. HCF includes EDCA (enhanced distributed channel access), which is a contention-based channel access method, and HCCA (HCF controlled channel access), which is a contention-free method using a polling mechanism. In addition, HCF includes a medium access mechanism to improve the QoS of WLAN, and can transmit QoS data in both a contention period (CP) and a contention-free period (CFP).

[0133] FIG. 4 is a diagram illustrating an example of a hidden node and an exposed node to which various embodiments of the present disclosure are applicable, and an example of an RTS and a CTS for solving the problem of the hidden node and the exposed node.

[0134] Figure 4 (a)(400) is an example of a hidden node. When STA A and STA B are communicating and STA C has information to transmit, STA A may determine that the medium is idle when performing carrier sensing before STA C sends data to STA B, even though STA A is transmitting the information to STA B. This is because STA A's transmission (i.e., medium occupancy) may not be sensed at STA C's location. In this case, STA B receives information from STA A and STA C simultaneously, resulting in a collision. In this case, STA A can be said to be a hidden node of STA C.

[0135] (b)(410) is an example of an exposed node. In a situation where STA B is transmitting data to STA A, STA C may have information to transmit to STA D. In this case, if STA C performs carrier sensing, it may determine that the medium is occupied due to the transmission of STA B. Accordingly, STA C must wait until the medium becomes idle even if it has information to transmit to STA D. However, in reality, STA A is outside the transmission range of STA C, so the transmission from STA C and the transmission from STA B may not collide from the perspective of STA A, and thus STA C unnecessarily waits until STA B stops transmitting. In this case, STA C can be called an exposed node of STA B.

[0136] In order to effectively utilize the collision avoidance mechanism in the above situation, short signaling packets such as RTS (request to send) and CTS (clear to send) can be utilized. An STA that wishes to transmit data transmits an RTS to an STA that will receive the data, and the receiving STA that receives the RTS responds to the transmitting STA with a CTS frame. The RTS and / or CTS between two STAs can be overheard by surrounding STA(s), allowing the surrounding STA(s) to consider whether information should be transmitted between the two STAs.

[0137] (c)(420) is an example of a method for solving the hidden node problem. Assume that both STA A and STA C want to transmit data to STA B. When STA A transmits an RTS to STA B, STA B transmits a CTS to STA A. STA C, which overhears the RTS and CTS, delays its medium access until STA A and STA B finish transmitting data, thereby avoiding collisions.

[0138] (d)(430) is an example of a method for solving the exposed node problem. STA B, which wants to transmit data to STA A, transmits an RTS, and STA A, which is to receive the data, can respond to the RTS by transmitting a CTS. In this case, if STA C receives only the RTS transmitted by STA B and does not receive the CTS transmitted by STA A, STA C can know that STA A is outside the carrier sensing area of ​​STA C. In this case, STA C can determine that no collision will occur even if it transmits data to another STA (e.g., STA D), and can transmit the data.

[0139] FIG. 5 is a diagram illustrating an example of a frame structure used in an IEEE 802.11 system to which various embodiments of the present disclosure are applicable.

[0140] The PPDU (physical layer protocol data unit) format can be composed of a short training field (STF), a long training field (LTF), a SIGNAL (SIG) field, and a data field. The most basic (e.g., non-HT (high throughput)) PPDU frame format can be composed of only the legacy-STF (L-STF), legacy-LTF (L-LTF), a SIG field, and a data field.

[0141] STF can be used for frame timing acquisition, automatic gain control (AGC), diversity detection, and coarse frequency / time synchronization. LTF can be used for fine frequency / time synchronization and channel estimation. The STF and LTF together can be called the PLCP preamble, and the PLCP preamble can be considered a signal for OFDM physical layer synchronization and channel estimation.

[0142] The SIG field can be used to transmit control information for demodulation and decoding of the data field. The SIG field can include information about the data rate and data length. Additionally, the SIG field can include a parity bit, a SIG TAIL bit, etc.

[0143] The data field may include a SERVICE field, a physical layer service data unit (PSDU), a PPDU TAIL bit, and, if necessary, padding bits. Some bits of the SERVICE field may be used for a descrambler at the receiver. The PSDU corresponds to an MPDU (mac protocol data unit) defined at the MAC layer and may contain data generated / used by upper layers. The PPDU TAIL bit may be used to return the encoder to a 0 state. The padding bit may be used to adjust the length of the data field to a predetermined unit.

[0144] MPDU is defined according to various MAC frame formats, and a basic MAC frame consists of a MAC header, frame body, and FCS (frame check sequence). MAC frame is composed of MPDU and can be transmitted / received through PSDU of the data part of PPDU format.

[0145] The MAC header is defined as an area that includes a frame control field, a duration / ID field, an address 1 field, an address 2 field, an address 3 field, a sequence control field, an address 4 field, a QoS control field, and an HT control field.

[0146] The Frame Control field contains information about the characteristics of the corresponding MAC frame. The Segment / Identifier field may be implemented to have different values ​​depending on the type and subtype of the corresponding MAC frame.

[0147] The Address 1 field to the Address 4 field are used to indicate the BSSID, source address (SA), destination address (DA), transmitting address (TA) indicating the transmitting STA address, and receiving address (RA) indicating the receiving STA address.

[0148] The sequence control field is set to include a sequence number and a fragment number. The sequence number can indicate the sequence number assigned to the corresponding MAC frame. The fragment number can indicate the number of each fragment of the corresponding MAC frame.

[0149] The QoS Control field contains information related to QoS. The QoS Control field may be included when the Subtype subfield indicates a QoS data frame. The HT Control field contains control information related to HT and / or VHT transmission and reception techniques.

[0150] The frame body is defined as the MAC payload, contains the data to be transmitted from the upper layer, and has a variable size. For example, the maximum MPDU size is 11,454 octets, and the maximum PPDU size can be 5.484 ms.

[0151] FCS is defined as a MAC footer and is used to detect errors in MAC frames.

[0152] The first three fields (Frame Control, Segment / Identifier, and Address 1) and the last field (FCS) constitute the minimum frame format and are present in all frames. The remaining fields may only be present in certain frame types.

[0153] Below is a description of the network allocation vector (NAV) used in wireless LAN networks.

[0154] As mentioned above, the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing, in which the AP and / or STA directly sense the medium. Virtual carrier sensing is intended to address potential issues in medium access, such as the hidden node problem. For virtual carrier sensing, the MAC of the wireless LAN system can utilize NAV. NAV is a value that indicates to other APs and / or STAs the remaining time until the medium becomes available, by the AP and / or STA currently using or authorized to use the medium. Therefore, the value set as NAV corresponds to the period during which the medium is scheduled to be used by the AP and / or STA transmitting the frame, and the STA receiving the NAV value is prohibited from accessing the medium during the period. NAV can be set, for example, according to the value of the duration field of the MAC header of the frame.

[0155] FIG. 6 is a diagram illustrating an example of NAV settings to which various embodiments of the present disclosure can be applied.

[0156] Referring to FIG. 6, a source STA (source STA, 600) transmits an RTS frame after DIFS, and a destination (destination) (610) transmits a CTS frame after SIFS. The destination STA designated as the receiver through the RTS frame does not set an NAV. Some of the remaining STAs (620) may receive the RTS frame and set an NAV (630), and some may receive the CTS frame and set an NAV (640).

[0157] If a CTS frame (e.g., PHY-RXSTART.indication primitive) is not received within a certain period from the time when the RTS frame is received (e.g., the time when the MAC receives the PHY-RXEND.indication primitive corresponding to the RTS frame), STAs that have set or updated the NAV through the RTS frame may reset the NAV (e.g., to 0). The certain period may be (2*aSIFSTime + CTS_Time + aRxPHYStartDelay + 2*aSlotTime). The CTS_Time may be calculated based on the length of the CTS frame and the data rate indicated by the RTS frame. The certain period may be a NAVTimeout period.

[0158] In Fig. 6, for convenience, setting or updating NAV through an RTS frame or a CTS frame is illustrated, but NAV setting / resetting / updating may also be performed based on various other frames, such as a non-HT PPDU, HT PPDU, VHT PPDU, or an interval field of a HE PPDU (for example, an interval field in a MAC header of a MAC frame).

[0159] 802.11ax also introduces basic NAV and intra-BSS NAV. Basic NAV is always set by frames transmitted by APs or STAs other than itself (mandatory), and intra-BSS NAV can be optionally set by frames transmitted from the BSS to which the AP or STA belongs. An AP or STA can access the medium when both NAV timers have expired (or after all NAV time intervals have elapsed).

[0160] Below, we describe TXOP (transmission opportunity). TXOP is a new feature introduced in the 802.11e MAC to ensure QoS and improve channel utilization. To ensure QoS, TXOP can be used to assign priority transmission opportunities when two or more packets fall into the same access category (AC).

[0161] FIG. 7 is a diagram illustrating an example of a TXOP to which various embodiments of the present disclosure can be applied.

[0162] STAs participating in QoS transmission can obtain TXOPs, which allow them to transmit traffic for a certain period of time, using two channel access methods: EDCA and HCCA. TXOPs can be acquired either by successfully competing in EDCA or by receiving a QoS CF-Poll (Contention-Free Poll) frame from the AP. The former is called an EDCA TXOP, and the latter is called a Polled TXOP. In this way, the concept of TXOP can be used to grant a certain amount of time for a STA to transmit a frame, or to forcibly limit the transmission time.

[0163] The transmission start time and maximum transmission time of TXOP are determined by the AP, which is notified to the STA by a beacon frame for EDCA TXOP and by a QoS CF-Poll frame for Polled TXOP.

[0164] NAV can be understood as a kind of timer to protect the TXOP of a transmitting STA (e.g., a TXOP holder). An STA can protect the TXOP of another STA by not performing channel access while the NAV set for itself is valid. In the current wireless LAN system, the TXOP duration is set through the duration field of the MAC header. That is, the TXOP holder and the TXOP responder (e.g., the Rx STA) transmit the entire TXOP information required for transmitting and receiving frames by including it in the duration field of the frames they transmit and receive. Third-party STAs that are not the TXOP holder or the TXOP responder (e.g., third-party STAs) check the Duration field of the frames exchanged between the TXOP holder and the TXOP responder, and postpone channel use until the NAV duration by setting / updating the NAV.

[0165] Below we describe the 802.11be standard. 802.11be, also known as EHT (extremely high throughput), operates in the 2.4, 5, and 6 GHz bands and is being developed to provide speeds up to 46 Gbps, which is 4.8 times faster than WiFi 6, by introducing 320 MHz of bandwidth, 4096QAM, multiple resource units (RUs), and multi-link operation (MLO), while providing low latency and high network throughput. Specifically, 802.11be provides a wide bandwidth of 320 MHz in the 6 GHz band, and can transmit data via MU-MIMO with 16 spatial streams in both the uplink and downlink, and adopts 4096QAM to achieve high transmission efficiency. In addition, it has the characteristics of increasing spectrum efficiency by flexibly performing spectrum resource scheduling through multiple RUs, and simultaneously transmitting and receiving data in various frequency bands and channels through multi-link operation.

[0166] FIG. 8 is a diagram illustrating an example of an operation for coordinated time division multiplexing access (C-TDMA) to which various embodiments of the present disclosure are applicable.

[0167] C-TDMA is a technology that cooperates with each other to enable time-sharing access between APs. For example, this can be accomplished through TXOP sharing between APs. An AP occupying a TXOP can share its TXOP with an AP expected to process traffic. In this case, the AP that shares the TXOP can be referred to as a sharing AP, and the AP that has received the TXOP can be referred to as a shared AP. Hereinafter, a TXOP shared / allocated / transferred from a sharing AP to a shared AP can be referred to as a shared TXOP.

[0168] Referring to FIG. 8, in the step of setting the C-TDMA configuration, basic configuration information for C-TDMA operation can be shared between APs (810). For example, information for C-TDMA operation can include capability information of each AP and configuration information for C-TDMA of each AP. The capability information of the AP can include at least one of information on QoS and / or traffic that the AP can support, security-related information that the AP can support, access methods that the AP can support, data transmission rates and NSS (number of spatial streams) supported by the AP, and configuration information for C-TDMA can include at least one of information on whether TXOP return is set for each AP and information necessary for processing its own traffic that is generated periodically.

[0169] Also, for example, for long-term C-TDMA operation (820), information about periodic traffic can be shared between APs in the step of setting C-TDMA settings between APs (810). The information about the periodic traffic can include information about the properties or expected QoS of the periodic traffic. Specifically, the information can include information about a traffic identifier (TID) set to the AP or expected to be transmitted and received by the AP, a (nominal or maximum) size of traffic (e.g., MSDU (MAC service data unit)) for each TID, an interval, a data rate (e.g., maximum, average, minimum), a direction of uplink or downlink, etc. Each AP can share the information about the periodic traffic to predict the periodic traffic to be processed by each AP in the C-TDMA process and perform C-TDMA operation (820).

[0170] Additionally, for short-term operation (830), information about aperiodic traffic can be shared between APs. For example, such sharing can be performed through a C-TDMA information exchange operation (830). The C-TDMA information exchange operation can be performed, for example, by transmitting and receiving a BSR (buffer state report). For example, the BSR can include information about the size of traffic stored in the buffer for each AC, the nature of the traffic, QoS, priority of the traffic, etc. The BSR can be transmitted in response to a request to receive a BSR, or when a specific condition is satisfied, such as when the size of the traffic stored in the buffer (or the size of the buffer can be used interchangeably) is set or exceeds a predetermined threshold, or it can be transmitted periodically.

[0171] And / or, the C-TDMA information exchange operation may be performed, for example, through NFRP (NDP (null data PPDU) feedback report poll). When the transmitter transmits an NFRP trigger frame, the receiver may transmit an NDP feedback report response in response. The NDP feedback report response may include information indicating whether the size of the buffer is greater than or equal to a threshold. The transmitter may predict the buffer status of the receiver through the response.

[0172] Each AP can share information about the aperiodic traffic, share resources for aperiodic traffic during the C-TDMA process, and perform C-TDMA operations (840). The C-TDMA information exchange operations described above are not limited by the messages described above.

[0173] Through the above information sharing, the sharing AP can predict the amount (or length) of TXOPs to be shared with the shared AP before the C-TDMA operation and perform TXOP sharing. If the sharing AP can accurately predict the length of the TXOP section required by the shared AP through the above information sharing, the TXOP return, in which the shared AP returns the shared TXOP to the shared AP, may not be necessary. For this operation, whether or not to perform the TXOP return operation may be optional for the AP.

[0174] FIG. 9 is a diagram illustrating an example of multiple MP (M-AP) TXOP sharing to which various embodiments of the present disclosure are applicable.

[0175] Referring to FIG. 9, AP2 (920) formed a BSS with STA3 (930) and STA4 (932) (hereinafter referred to as BSS2), AP1 (900) formed a BSS with STA1 (910) and STA2 (912) (hereinafter referred to as BSS1), and AP3 (940) formed a BSS with STA5 (950) and STA6 (952) (hereinafter referred to as BSS3). In this case, when AP2 (920) shares its TXOP with AP3 (952), AP2 (920) corresponds to a sharing AP, and AP3 (940) corresponds to a shared AP. TXOP sharing between APs of the present disclosure is not limited by the example of FIG. 9.

[0176] FIG. 10 illustrates an example of a low-latency (LL) traffic transmission and reception process in C-TDMA to which various embodiments of the present disclosure are applicable.

[0177] Referring to FIG. 10, for example, in C-TDMA, a sharing AP (AP1) owns a TXOP and can share the period of TXOP with a shared AP (AP2). The sharing AP (AP1) can share its TXOP with the shared AP (AP2) by transmitting an MRTT (multi-user RTS TXOP sharing trigger frame, MU-RTS TXS TF). The shared AP (AP2) can transmit a CTS in response to the MRTT and be allocated a shared TXOP period within the TXOP of the sharing AP (AP1). The shared AP (AP2) can perform communication within the shared TXOP period. For example, the shared AP (AP2) can transmit data to (Non-AP) STA2 within the shared TXOP period and receive a BA (block ACK) for the data from STA2.

[0178] Preemption can be considered for LL (low latency). Generally, when a TXOP is obtained, other APs / STAs except for the AP / STA that obtained the TXOP cannot transmit. However, considering services for LL traffic, etc., even if there is an AP / STA that obtained a TXOP, preemption is being discussed so that other APs / STAs can transmit LL traffic (or high-priority traffic) if the AP / STA that obtained the TXOP allows it.

[0179] When implementing preemption in C-TDMA, a shared AP, AP2, can allow preemption within its own BSS. For example, AP2 can allow preemption for ongoing transmissions within its own BSS, e.g., AP2 and / or STA2, if necessary. That is, AP2 can allow preemption within the shared TXOP interval.

[0180] However, if LL traffic arrives (occurs) during the shared TXOP interval shared by AP1, which is a sharing AP, with AP2, AP2 does not allow preemption for AP1. AP2 cannot allow preemption for AP1, which does not belong to its BSS. Therefore, AP1, as a (non-AP) STA1, may have to wait until the shared TXOP interval ends to transmit the data frame of the LL traffic. Accordingly, the preemption operation for the sharing AP needs to be defined.

[0181] FIG. 11 illustrates an example of a preemption operation in C-TDMA to which various embodiments of the present disclosure are applicable. FIG. 11 illustrates an example of a preemption operation for a sharing AP.

[0182] Referring to FIG. 11, AP1 can specify an allocation duration and transmit an MRTT to AP2 indicating AP1's preference for allowing preemption within the allocation duration. The MRTT can include information about the allocation duration and information indicating a preference for allowing preemption. The preemption can be allowed for AP1, which is a sharing AP, but not allowed for STA1, which is associated with AP1.

[0183] AP2 can send a CTS in response to the MRTT. After responding with the CTS for the MRTT, AP2 can decide whether to allow preemption based on AP1's preference.

[0184] For example, if AP2 does not allow preemption, AP1 cannot preemption.

[0185] For example, if AP2 allows preemption, AP2 can set that preemption is allowed in the PPDU (short PPDU) and transmit the PPDU (data). When AP2 transmits a PPDU to STA2 within the allocated interval, it can transmit it with preemption allowed. AP1 can transmit a preemption request (PReq) to AP2 within the interval allocated to AP2 and transmit LL traffic to STA1. STA1 can transmit a BA for the LL traffic. Afterwards, AP1 can transmit a preemption release (PRel) to AP2. Upon receiving the preemption release, AP2 can transmit a PPDU to STA2 with preemption allowed included in the PPDU within the allocated interval, and STA2 can transmit a BA for this.

[0186] FIG. 12 illustrates an example of a preemption operation in C-TDMA to which various embodiments of the present disclosure are applicable. FIG. 12 illustrates an example of a preemption operation for a sharing AP.

[0187] Referring to FIG. 12, AP1 may transmit a request frame requesting that AP2 allow preemption. Preemption may be allowed for AP1, which is a sharing AP, but not allowed for a non-AP STA (STA1 associated with AP1).

[0188] AP2, which receives the request frame, can decide whether to allow the preemption. AP2 can transmit a response frame containing information on whether to allow the preemption.

[0189] Based on the response frame from AP2, AP1 can determine the allocation interval of TXOP for AP2 and transmit an MRTT including information about the allocation interval to AP2.

[0190] For example, if AP2 allows pre-amnesia, AP1 can set the allocation period to be longer than a certain value, so that the allocation period is long enough for AP2 to participate in C-TDMA with pre-amnesia. AP2 can transmit a CTS in response to the MRTT. After responding with the CTS for the MRTT, AP2 can decide whether to allow pre-amnesia based on AP1's preference.

[0191] For example, if AP2 does not allow preemption, AP1 cannot preemption.

[0192] For example, if AP2 allows pre-amnesia, AP2 can set that pre-amnesia is allowed in the PPDU (short PPDU) and transmit the PPDU. When AP2 transmits a PPDU to STA2 within the allocated interval, it can transmit it with pre-amnesia allowed. AP1 can transmit a pre-amnesia request (PReq) to AP2 within the interval allocated to AP2 and transmit LL traffic to STA1. STA1 can transmit a BA for the LL traffic. Afterwards, AP1 can transmit a pre-amnesia release (PRel) to AP2. When AP2 receives the pre-amnesia release, it can transmit a PPDU to STA2 with pre-amnesia allowed included in the PPDU within the allocated interval, and STA2 can transmit a BA for this.

[0193] For example, if AP2 does not allow preemption, AP1 can set the allocation period to be shorter than a certain value.

[0194] In the pre-amplification operation in C-TDMA described with reference to FIGS. 11 and 12, a sharing AP that wishes to perform pre-amplification must transmit a pre-amplification request to the shared AP, and also transmit a pre-amplification release after the pre-amplification.

[0195] Various embodiments of the present disclosure propose a method for simplifying signaling procedures by enabling pre-amnesia without a pre-amnesia request / pre-amnesia release. Various embodiments of the present disclosure propose a method for enabling pre-amnesia without a pre-amnesia request / pre-amnesia release.

[0196] According to one embodiment of the present disclosure, in C-TDMA, a sharing AP can be configured to always (i.e., without explicit signaling) preemption during the middle of a TXOP (shared TXOP) that the sharing AP has transferred to the shared AP. In C-TDMA, it can be configured whether the sharing AP is allowed / capable of preemption within the shared TXOP (whether to perform a C-TDMA operation that allows preemption).

[0197] According to one embodiment of the present disclosure, a shared AP can perform transmission with a PIFS interval between an ACK for a transmitted PPDU and a next PPDU to be transmitted. If there is data requiring pre-amplification (e.g., LL traffic, LL data), the sharing AP can attempt transmission with a SIFS interval. If a pre-amplification operation of the sharing AP is set in TDMA according to one embodiment of the present disclosure, the shared AP can perform / attempt transmission with a PIFS interval, and the sharing AP can perform / attempt transmission for data for pre-amplification with a SIFS interval.

[0198] In the description of one embodiment of the present disclosure, it has been mainly described as an example that the shared AP performs transmission at PIFS intervals and the shared AP performs (or attempts) transmission at SIFS intervals, but this is exemplary and the present disclosure is not limited thereto. The transmission interval of the shared AP (e.g., PIFS) and the transmission interval of the shared AP (e.g., SIFS) in the description of one embodiment of the present disclosure may be changed within a range where the condition that the transmission interval of the shared AP is larger than the transmission interval of the shared AP (e.g., can be larger by 1 slot to 2 slots) and / or the condition that the transmission interval of the shared AP is larger than the SIFS are maintained. For example, the shared AP may attempt transmission at SIFS intervals, and the shared AP may perform transmission at an interval larger than the SIFS interval (e.g., PIFS, DIFS, etc.).

[0199] Unless specifically stated otherwise, in the description of an embodiment of the present disclosure, the word "more than" may be replaced with "more than," and the word "more than" may be replaced with "more than." Unless specifically stated otherwise, in the description of an embodiment of the present disclosure, the word "less than" may be replaced with "less than."

[0200] FIG. 13a is a diagram for explaining an example of a preemption operation in C-TDMA according to an embodiment of the present disclosure. FIG. 13b is a diagram for explaining an example of a preemption operation in C-TDMA according to an embodiment of the present disclosure.

[0201] FIG. 13 a and FIG. 13 b illustrate a preemption operation when a sharing AP in C-TDMA sets whether preemption is allowed / possible (whether to perform a C-TDMA operation in which preemption is allowed) within a shared TXOP according to an embodiment of the present disclosure. In FIG. 13 a and FIG. 13 b, it is illustrated that the sharing AP corresponds to BSS1, and the shared AP and STA correspond to BSS2.

[0202] Referring to FIG. 13A, according to one embodiment of the present disclosure, a sharing AP can share an acquired TXOP with the shared AP. The sharing AP can share its TXOP with the shared AP by transmitting an MU-RTS TXS TF. The shared AP can transmit a CTS after an SIFS from the MU-RTS TXS TF. The shared AP can perform communication within the shared TXOP period. The shared AP can transmit data after an SIFS from the CTS. The STA can transmit an ACK after an SIFS from the data. The shared AP can transmit data after a PIFS from the ACK. The STA can transmit an ACK after an SIFS from the data. The transmission and reception of data / ACK between the shared AP and the STA can continue until the end / expiration of the shared TXOP.

[0203] Referring to FIG. 13b, according to one embodiment of the present disclosure, a sharing AP can share an acquired TXOP with the shared AP. The sharing AP can share its TXOP with the shared AP by transmitting an MU-RTS TXS TF. Here, the sharing AP can be configured to always be able to preempt (during) the TXOP (shared TXOP) transferred (shared / allocated) to the shared AP. The shared AP can perform communication within the shared TXOP section. The shared AP can transmit a CTS after SIFS from the MU-RTS TXS TF. The STA can transmit an ACK after SIFS from the data. The shared AP can perform transmission at a PIFS interval from the ACK. Here, if data requiring preemption (e.g., LL data, LL traffic) occurs in the shared AP, the shared AP can transmit the data via preemption within the SIFS interval from the ACK. In this case, the shared AP can detect data transmission via preemption of the shared AP within the PIFS interval from the ACK, and in this case, it may not transmit the data.

[0204] Hereinafter, in the description of one embodiment of the present disclosure, a shared TXOP (or a shared TXOP section) and a TXOP of a shared AP (or a TXOP section of a shared AP) may be distinguished. The shared TXOP may refer to a TXOP that the shared AP has shared with the shared AP within its own TXOP as described above. The TXOP of the shared AP may refer to a section in which the shared AP performs (continuous) transmission and / or a section in which (continuous) transmission is possible and / or a section in which the shared AP performs one transmission and / or a section in which one transmission is possible, etc. within the shared TXOP. That is, the TXOP of one or more shared APs may be included in the shared TXOP, and at least a part of the shared TXOP may be the TXOP of the shared AP.

[0205] In the description of one embodiment of the present disclosure, the terms shared TXOP and TXOP of shared AP are used to describe the present disclosure according to the definitions above. However, the terms shared TXOP and TXOP of shared AP are for convenience of description, and the present disclosure is not limited to these specific terms.

[0206] In the description of one embodiment of the present disclosure, it is mainly described that the sharing AP shares TXOP by transmitting MU-RTS TXS TF to the shared AP, but this is exemplary and the control frame may be changed. For example, it may be a control frame for TXOP sharing.

[0207] In the description of one embodiment of the present disclosure below, performing preemption may include performing data transmission (e.g., LL data / traffic transmission) according to the preemption.

[0208] According to one embodiment of the present disclosure, the sharing AP may operate according to at least some of the following:

[0209] (1) According to one embodiment of the present disclosure, the sharing AP can set a limit on the TXOP duration of the shared AP based on the target delay (target delay, delay bound, time required / expected to be required for data transmission of the sharing AP) of the sharing AP. The length of the TXOP duration of the shared AP can be limited according to the target delay of the sharing AP. The sharing AP can limit the TXOP duration of the shared AP to be less than or equal to the maximum TXOP duration corresponding to the target delay of the sharing AP.

[0210] For example, if the target delay of the shared AP is 5ms, and the shared AP transmits packets / data in a section longer than 5ms within the shared TXOP, the target delay of the shared AP may not be satisfied, and thus the shared AP may not be able to transmit according to the preemption. Considering this, the present disclosure proposes that the shared AP sets the TXOP section of the shared AP based on the target delay of the shared AP.

[0211] For example, a shared AP can limit the TXOP interval of the shared AP by the target delay of the shared AP. The shared AP can transmit with the TXOP of the shared AP that is less than or equal to the limited length within the shared TXOP. Within the shared TXOP, the shared AP can transmit with the TXOP of the shared AP that is less than or equal to the target delay. That is, the target delay can be the maximum length of the TXOP interval of the shared AP. Alternatively, the target delay can correspond to the maximum length of the TXOP interval of the shared AP. For example, when the target delay of the shared AP exemplified above is 5ms, the TXOP of the shared AP can be limited to less than or equal to 5ms, for example, the shared AP can transmit within the TXOP of the shared AP of 3ms.

[0212] (2) According to one embodiment of the present disclosure, when a sharing AP needs to perform an LL traffic-related operation, i.e., when a data transmission via preemption needs to be performed, the sharing AP can perform preemption (data transmission via preemption) according to at least some of the following contents. The sharing AP can identify a time when preemption is possible according to at least some of the following contents.

[0213] - 1) If the transmission of the shared AP starts with a control frame (control frame, CF, e.g., ICF (initial control frame) / ICR (initial control response), RTS / CTS, TF (trigger frame), etc.) and the sharing AP receives (detects) an ACK adjacent to the end of the TXOP section of the shared AP, the sharing AP can perform preemption at SIFS intervals. If the transmission of the shared AP within the shared TXOP starts with a control frame, the TXOP section of the shared AP can be identified based on the control frame. If the sharing AP receives (detects) an ACK adjacent to the end of the TXOP section of the identified shared AP, the sharing AP can perform preemption at SIFS intervals. The sharing AP can perform preemption after SIFS from the ACK.

[0214] In the description of one embodiment of the present disclosure, receiving (detecting) an ACK at a time point adjacent to the end time of a TXOP period of a shared AP may be receiving (detecting) an ACK for data transmission of the shared AP. Receiving (detecting) an ACK at a time point adjacent to the end time of a TXOP period of the shared AP may be receiving (detecting) an ACK transmission of the shared AP. For example, the time point adjacent to the end time of the TXOP period of the shared AP may be within a certain interval (e.g., a SIFS interval) from the end time of the TXOP period of the shared AP.

[0215] - 2) If the transmission of the shared AP starts with a control frame, and the sharing AP does not receive (does not detect) an ACK adjacent to the end of the TXOP interval of the shared AP (or does not receive (detect) it), the sharing AP may perform transmission after a specific interval. If the transmission of the shared AP within the shared TXOP starts with a control frame, the TXOP interval of the shared AP may be identified based on the control frame. If the sharing AP does not receive (detect) an ACK adjacent to the end of the TXOP interval of the identified shared AP, the sharing AP may perform preemption at a specific interval. The sharing AP may perform preemption after a specific interval from a specific time point. A method for determining / identifying a specific time point / specific interval according to an embodiment of the present disclosure is described below.

[0216] - 3) If a transmission from a shared AP starts with a data frame and the shared AP receives (detects) an ACK, the shared AP can perform preemption at SIFS intervals. If a transmission from a shared AP within a shared TXOP starts with a data frame and the shared AP receives (detects) an ACK for the data frame, the shared AP can perform preemption at SIFS intervals.

[0217] - 4) If the transmission of the shared AP starts with a data frame and the shared AP does not receive (detect) an ACK, the shared AP may perform preemption after a specific interval. If the transmission of the shared AP within the shared TXOP starts with a data frame and the shared AP does not receive (detect) an ACK for the data frame, the shared AP may perform preemption after a specific interval from a specific point in time. A method for determining / identifying a specific point in time / specific interval according to an embodiment of the present disclosure is described below.

[0218] According to one embodiment of the present disclosure, a specific point in time / a specific interval may be determined / identified / calculated based on at least some of the following: The Sharing AP may determine / identify / calculate a specific point in time / a specific interval based on at least some of the following:

[0219] - 1) If the TXOP interval of the shared AP can be acquired, preemption can be performed after SIFS after the end of the TXOP interval of the shared AP. If the TXOP interval of the shared AP can be acquired, the specific point in time can be the end of the TXOP interval of the shared AP, and the specific interval can be SIFS. If the TXOP interval of the shared AP can be acquired, it can respond when the transmission of the shared AP within the shared TXOP described above starts with a control frame.

[0220] - 2) If it is impossible to acquire the TXOP interval of the shared AP, pre-amnesia may be performed after 2 * SIFS + ACK duration after reception / detection of the last data (data frame). Pre-amnesia may be performed after 2 * SIFS + ACK duration from the end time of the last data received / detected. If it is possible to acquire the TXOP interval of the shared AP, the specific point in time may be the reception / detection time of the last data (the end time of the last data detected for reception), and the specific interval may be 2 * SIFS + ACK duration. If it is impossible to acquire the TXOP interval of the shared AP, it may correspond to the case where the transmission of the shared AP within the above-described shared TXOP starts with a data frame. Here, the ACK duration may be calculated / acquired based on the minimum value of a predefined data rate (bitrate) (for example, 6 Mbps (megabits per second)). This may be to ensure that ACK transmission for the last data is guaranteed.

[0221] For example, the last data may be the most recently received / detected data from the shared AP. It may be the most recently received / detected data from the shared AP or an STA belonging to the BSS of the shared AP. The end point of the last data may be identified as follows.

[0222] - - 1) It can be identified based on the PHY (physical layer) header (preamble) of the last data. For example, the rate (RATE) field and the length (LENGTH) field of the PHY header can be used. The end point of the last data can be identified / obtained / calculated based on the rate field and the length field of the PHY header. By dividing the number of bits identified from the length field by the rate (data rate (bit rate)) identified from the rate field, the time length corresponding to the last data can be obtained, and thus the end point of the last data can be identified / obtained / calculated.

[0223] - - 2) It can be identified based on the MAC header of the last data. For example, the Duration / ID field of the NAC header can be used. Table 1 shows an example of the Duration / ID field (encoding) of the MAC header.

[0224] [Table 1]

[0225]

[0226] Referring to Table 1, for example, when the values ​​of bits B0 to B14 (15 MSBs (most significant bits)) of the Duration / ID field (2 octets, 16 bits) are 0 to 32767 and B15 (1 LSB (least significant bit)) is 0, it indicates an interval value. That is, since the time length corresponding to the last data can be obtained from the Duration / ID field of the MAC header, the end point of the last data can be identified / obtained.

[0227] - - 3) The end point of reception of the last data can be identified / obtained based on energy detection. Considering that the last data is not for the sharing AP, the end point of reception of the last data can be detected by energy detection of the medium rather than performing decoding on the data.

[0228] (3) According to one embodiment of the present disclosure, the operation after pre-amendment may vary depending on whether the sharing AP re-assigns / re-shares the TXOP to the shared AP after the pre-amendment. For example, if the shared TXOP expires after the pre-amendment, the sharing AP may not re-assign / re-share the TXOP. If the shared TXOP does not expire even after the pre-amendment, the sharing AP may re-assign / re-share the TXOP. However, the present invention is not limited thereto, and even if the shared TXOP expires after the pre-amendment, the sharing AP may share the TXOP back to the shared AP (for example, by sharing it through an explicit method described below).

[0229] - 1) If the sharing AP does not reassign / reshare the TXOP to the shared AP after preemption, the sharing AP can continue to use the TXOP at SIFS intervals. In other words, the sharing AP can perform transmission at SIFS intervals within the TXOP.

[0230] - 2) If the sharing AP re-assigns / re-shares the TXOP to the shared AP after pre-amnesty, the shared AP can perform transmission within the re-assigned / re-shared shared TXOP. In this case, the sharing AP can explicitly or implicitly indicate to the shared AP that it has re-assigned / re-shared the TXOP. For example, the sharing AP can explicitly indicate to the shared AP that it has re-assigned / re-shared the TXOP by transmitting a control frame (e.g., MU-RTS TXS TF, a control frame for TXOP sharing). For example, the sharing AP can implicitly indicate to the shared AP that it has re-assigned / re-shared the TXOP by not using the TXOP (i.e., not performing any transmission) for a time interval longer than SIFS (e.g., PIFS, i.e., a time interval longer than the time interval during which the sharing AP attempts to transmit in pre-amnesty).

[0231] According to one embodiment of the present disclosure, a shared AP may operate according to at least some of the following:

[0232] (1) According to one embodiment of the present disclosure, a shared AP can perform transmission at PIFS intervals after acquiring one TXOP. A shared AP can perform transmission at PIFS intervals within a shared TXOP.

[0233] - When the shared AP initiates transmission with a control frame (e.g., ICF / ICR, RTS / CTS, TF (trigger frame), etc.), the shared AP can perform transmission within the TXOP of the shared AP corresponding to the control frame. After that, the shared AP can re-acquire the TXOP of the shared AP at PIFS intervals within the shared TXOP. That is, the TXOP of the shared AP can be re-acquired starting after the PIFS interval from the end point of the initially acquired shared TXOP.

[0234] - When a shared AP initiates a transmission with a data frame, the shared AP can perform transmission at PIFS intervals within the shared TXOP. Here, even if retransmission is required, the shared AP can perform retransmission at PIFS intervals within the shared TXOP.

[0235] (2) According to one embodiment of the present disclosure, the TXOP of the shared AP may be within a TXOP interval limited by the shared AP within the shared TXOP. As described above, the shared AP may set a limit on the TXOP interval of the shared AP, and in this case, the shared AP may obtain / identify the TXOP of the shared AP so as to be less than or equal to the set / limited maximum TXOP interval.

[0236] (3) According to one embodiment of the present disclosure, the shared AP can return the shared TXOP to the shared AP by transmitting a specific frame. For example, the shared AP can return the shared TXOP by transmitting a control frame (e.g., CF-End) to the shared AP. For example, if the TXOP section (section for transmission within the actual shared AP / shared AP BSS) that the shared AP intends to perform (or needs to perform) transmission is less than the remaining section of the limited TXOP section, the shared AP can return the shared TXOP to the shared AP with a control frame (e.g., CF-End). In this case, the shared AP can return the shared TXOP to the shared AP so that the shared AP can perform transmission in the TXOP corresponding to the remaining section of the shared TXOP, and thus, waste of the TXOP can be prevented from the perspective of the shared AP. This is an example, and the shared AP may perform transmission within the remaining TXOP without returning the remaining CF-END. Conversely, if the TXOP interval (the interval for transmission within the actual shared AP / shared AP BSS) that the shared AP intends to perform transmission (or requires) is larger than the remaining interval of the limited TXOP interval, the shared AP may perform transmission in a divided manner. For example, the shared AP may divide the TXOP interval it intends to perform transmission, perform transmission in the remaining TXOP interval, and then transmit in the remaining divided TXOP interval.

[0237] (4) According to one embodiment of the present disclosure, if a shared TXOP remains even after the preemption of the sharing AP (if the sharing AP reassigns / reshares the TXOP), the shared AP can perform transmission within the reassigned / reshared shared TXOP. In this case, the shared AP can be explicitly or implicitly instructed by the sharing AP that the TXOP has been reassigned / reshared. For example, the shared AP can receive a control frame (e.g., a control frame for MU-RTS TXS TF. TXOP sharing) from the sharing AP, thereby being explicitly instructed that the sharing AP has reassigned / reshared the TXOP. For example, if the medium is idle for a time interval longer than SIFS (e.g., PIFS, i.e., a time interval longer than the time interval during which the sharing AP attempts to transmit in preemption), the shared AP may consider this an implicit indication that the sharing AP has relinquished / reshared the TXOP.

[0238] According to one embodiment of the present disclosure, if there are no shared TXOPs left after the preemption of the sharing AP (if the sharing AP does not reassign / reshare the TXOP), the shared AP no longer performs transmissions within the TXOP of the sharing AP.

[0239] According to one embodiment of the present disclosure, in C-TDMA, the setting of whether a sharing AP allows / can allow preemption within a shared TXOP (whether to perform a C-TDMA operation in which preemption is allowed) may be based on one or more of the following methods.

[0240] (1) Method 1 - Method represented in MU-RTS TXS TF

[0241] According to one embodiment of the present disclosure, in C-TDMA, a setting for whether a sharing AP allows / can preemption within a shared TXOP (whether to perform a C-TDMA operation in which preemption is allowed) can be indicated in an MU-RTS TXS TF.

[0242] According to one embodiment of the present disclosure, one or more of the reserved fields / subfields and / or the reserved values ​​of specific fields / subfields included in the MU-RTS TXS TF may indicate whether pre-amnesia is allowed / possible (whether to perform a C-TDMA operation in which pre-amnesia is allowed) by a sharing AP within a shared TXOP in C-TDMA. That is, one or more of the fields / subfields defined as reserved included in the MU-RTS TXS TF may be newly defined as fields / subfields for indicating whether pre-amnesia is allowed / possible (whether to perform a C-TDMA operation in which pre-amnesia is allowed) by a sharing AP within a shared TXOP in C-TDMA. And / or one or more of the fields / subfields defined as reserved values ​​of specific fields / subfields included in the MU-RTS TXS TF may be newly defined with values ​​to indicate whether the sharing AP in C-TDMA allows / possibly preemption within the shared TXOP (whether to perform C-TDMA operations where preemption is allowed).

[0243] Below are examples of how a sharing AP in C-TDMA indicates in a MU-RTS TXS TF that preemption is allowed / possible within a shared TXOP (whether to perform a C-TDMA operation where preemption is allowed), which are exemplary and the present disclosure is not limited thereto.

[0244] Table 2 shows an example of the Triggered TXOP Sharing Mode subfield (encoding) of the MU-RTS TXS TF.

[0245] [Table 2]

[0246]

[0247] Referring to Table 2, if the value of the Triggered TXOP Sharing Mode subfield is 3, it is reserved. According to one embodiment of the present disclosure, based on the reserved value 3 of the Triggered TXOP Sharing Mode subfield, in C-TDMA, it can be indicated whether preemption is allowed / possible (whether to perform a C-TDMA operation in which preemption is allowed) within the shared TXOP by the sharing AP. For example, Table 2 can be modified as in Table 3.

[0248] [Table 3]

[0249]

[0250] FIG. 14 is a diagram for explaining an example of a method for transmitting and receiving configuration information for a preemption operation of a sharing AP in C-TDMA according to an embodiment of the present disclosure. FIG. 14 is a diagram for explaining an example of a method for a sharing AP in C-TDMA to indicate whether preemption is allowed / possible within a shared TXOP (whether a C-TDMA operation in which preemption is allowed is performed).

[0251] Figure 14 illustrates an example of an EHT (extremely high throughput) variant Common Info field format. The EHT variant Common Info field may be included in the MU-RTS TXS TF.The EHT variant Common Info field includes a Trigger Type subfield (4 bits, B0 to B3), a UL Length subfield (12 bits, B4 to B15), a More TF (trigger frame) subfield (1 bit, B16), a CS (carrier sense) Required subfield (1 bit, B17), a UL BW (bandwidth) subfield (2 bits, B18 to B19), a GI (guard interval) And HE (high efficiency) / EHT-LTF (long training field) Type / Triggered TXOP Sharing Mode subfield (2 bits, B20 to B21), a Reserved subfield (1 bit, B22), a Number Of HE / EHT-LTF Symbols subfield (3 bits, B23 to B25), a Reserved subfield (1 bit, B26), a LDPC (low-density parity check) Extra Symbol Segment subfield (1 bit, B27), and an AP Tx Power subfield (6 bits, B28 to B29). B33), Pre-FEC forward error correction) Padding Factor subfield (2 bits, B34 to B35), PE (packet extension) Disambiguity subfield (1 bit, B36), UL Spatial Reuse subfield (16 bits, B37 to B52), Reserved subfield (1 bit, B53), HE / EHT P160 subfield (1 bit, B54), Special User Info Field Flag subfield (1 bit, B55), EHT Reserved subfield (7 bits, B56 to B62), Reserved subfield (1 bit, B63), Trigger Dependent Common Info subfield (variable).According to one embodiment of the present disclosure, the Reserved subfield within the EHT variant Common Info field may be used to convey information indicating whether preemption is allowed / possible (whether to perform a C-TDMA operation where preemption is allowed) within a shared TXOP by a sharing AP in C-TDMA. That is, B22, B26, B53 or B63 within the EHT variant Common Info field may be used as a 1-bit notification.

[0252] FIG. 15 is a diagram for explaining an example of a method for transmitting and receiving configuration information for a preemption operation of a sharing AP in C-TDMA according to an embodiment of the present disclosure. FIG. 15 is a diagram for explaining an example of a method for a sharing AP to indicate whether preemption is allowed / possible within a shared TXOP (whether a C-TDMA operation in which preemption is allowed is performed) in C-TDMA according to an embodiment of the present disclosure.

[0253] Fig. 15 illustrates an example of an EHT variant User Info field format. The EHT variant User Info field may be included in an MU-RTS TXS TF. The EHT variant User Info field may include an AID12 subfield (12 bits, B0 to B11), a RU (resource unit) Allocation subfield (8 bits, B12 to B19), a UL FEC Coding Type subfield (1 bit, B20), a UL EHT-MCS (Modulation and Coding Scheme) subfield (4 bits, B21 to B24), a Reserved subfield (1 bit, B25), an SS (Spatial Stream) Allocation subfield (6 bits, B26 to B31), a UL Target Receive Power subfield (7 bits, B32 to B38), a PS160 subfield (1 bit, B39), and a Trigger Dependent User Info subfield (variable). According to one embodiment of the present disclosure, the Reserved subfield within the EHT variant User Info field may be used to convey information indicating whether preemption is allowed / possible (whether to perform a C-TDMA operation where preemption is allowed) within a shared TXOP by a sharing AP in C-TDMA. That is, B25 within the EHT variant User Info field may be used as a 1-bit notification.

[0254] According to one embodiment of the present disclosure, a separate control frame may be defined. The control frame may be defined for configuration information for a preemption operation of a shared AP in C-TDMA. The control frame may include at least a part of the configuration information for the preemption operation of the shared AP in C-TDMA. For example, the control frame may include information that the shared AP shares a TXOP with the shared AP. For example, the control frame may include information indicating whether preemption is allowed / possible (whether to perform a C-TDMA operation in which preemption is allowed) within the shared TXOP of the shared AP in C-TDMA. For example, the control frame may include information on a TXOP limitation of the shared AP (information on a TXOP section that the shared AP can use at one time within the shared TXOP. Information on a maximum value of the TXOP of the shared AP). The control frame may include fields / subfields representing each piece of information.

[0255] (2) Method 2 - Method indicated in the negotiation stage prior to TXS

[0256] FIG. 16 is a diagram for explaining an example of a method for transmitting and receiving setup information for preemption operation of a sharing AP in C-TDMA according to one embodiment of the present disclosure.

[0257] In C-TDMA operation, it is considered that pre-configuration is performed for discovery and / or information exchange between APs. For more detailed information on the configuration process, please refer to the description provided with reference to FIG. 8.

[0258] Referring to FIG. 16, in the step of setting the C-TDMA configuration, basic setting information for C-TDMA operation can be shared between APs, and the setting information can include at least some of the setting information for the preemption operation of the shared AP in C-TDMA. For example, the setting information can include information indicating whether preemption is allowed / possible for the shared AP in C-TDMA within the shared TXOP (whether to perform the C-TDMA operation in which preemption is allowed). For example, the setting information can include information on the TXOP limit of the shared AP (information on the TXOP section that the shared AP can use at one time within the shared TXOP. Information on the maximum value of the TXOP of the shared AP).

[0259] (3) Method 3 - Method indicated in the selection step before TXS

[0260] FIG. 17 is a diagram for explaining an example of a method for transmitting and receiving setup information for preemption operation of a sharing AP in C-TDMA according to one embodiment of the present disclosure.

[0261] Before C-TDMA operation, a control message (control frame) may be used so that the sharing AP can identify the status of specific APs. The sharing AP can determine which AP among the specific APs will share the TXOP based on the identified status / information. Before sharing the TXOP it has acquired, the sharing AP can identify information about one or more APs (APs that can become shared APs) through a control message. For example, the control message may use, but is not limited to, BRSP (buffer status report pool) and / or NFRP (NDP feedback report poll). In this process, at least a part of the configuration information for the preemption operation of the sharing AP in C-TDMA may be included.

[0262] According to one embodiment of the present disclosure, the control message may include at least a part of configuration information for a preemption operation of a shared AP in C-TDMA. For example, the control message may include information indicating whether preemption is allowed / possible for the shared AP in C-TDMA within a shared TXOP (whether to perform a C-TDMA operation in which preemption is allowed). For example, the control message may include information on a TXOP limitation of the shared AP (information on a TXOP section that the shared AP can use at one time within the shared TXOP. Information on a maximum value of the TXOP of the shared AP).

[0263] FIG. 17 illustrates a sharing AP corresponding to BSS1, a shared AP1 corresponding to BSS2, and a shared AP2 corresponding to BSS3. The sharing AP can transmit a control message within the acquired TXOP. The shared AP1 and shared AP2, which receive the control message, can transmit a response message thereto. The response message transmitted by the shared AP1 may include information of the shared AP1 requested by the sharing AP. The response message transmitted by the shared AP2 may include information of the shared AP2 requested by the sharing AP. Here, the control message transmitted by the sharing AP may include configuration information for the preemption operation of the sharing AP in C-TDMA. The control message may include information on the TXOP limit of the shared AP (information on the TXOP section that the shared AP can use at one time within the shared TXOP. Information on the maximum value of the TXOP of the shared AP).

[0264] Afterwards, the shared AP can transmit MU-RTS TXS TF. Shared AP1 can transmit CTS after SIFS from MU-RTS TXS TF. Shared AP1 can perform communication within the shared TXOP period. Shared AP1 can transmit data after SIFS from CTS. Shared AP1 can transmit data to STA included in BSS2. STA can transmit ACK after SIFS from data. Shared AP1 can transmit data after PIFS from ACK. STA can transmit ACK after SIFS from data. That is, since information indicating whether preemption is allowed / possible (whether to perform C-TDMA operation in which preemption is allowed) in shared TXOP in C-TDMA is transmitted in the control message, shared AP1 can transmit data at PIFS intervals. In addition, since information about the TXOP limit of the shared AP (information about the TXOP section that the shared AP can use at one time within the shared TXOP; information about the maximum value of the TXOP of the shared AP) is transmitted in the control message, the section corresponding to the data transmitted by shared AP1 (the TXOP of the shared AP) can be less than or equal to the maximum value of the TXOP. The transmission and reception of data / ACK between shared AP1 and the STA can continue until the end / expiration of the shared TXOP.

[0265] (4) Method 4 - A method indicated in a TF including a TXS Query transmitted prior to a control frame exchange for TXS operation (e.g., MU-RTS TXS TF / CTS exchange)

[0266] FIG. 18 is a diagram illustrating an example of a method for transmitting and receiving configuration information for a preemption operation of a sharing AP in C-TDMA according to an embodiment of the present disclosure. FIG. 18 illustrates a TXS Query field included in a TF and a TXS Response field included in a response thereto. For example, a TXOP information subfield within the TXS Query field may include a limited TXOP duration indicator and a length value of the TXOP duration. For example, information indicating a length value of the TXOP duration may be 2 octets.

[0267] The Common Info field included in the trigger frame may include a Trigger Type subfield. The Trigger Type subfield indicates a trigger frame variant. The Trigger Type subfield can be encoded as shown in Table 4, and the trigger frame variant corresponding to the value of each Trigger Type subfield can be referred to in Table 4.

[0268] [Table 4]

[0269]

[0270] Referring to Table 4, values ​​9 to 15 of the Trigger Type subfield are reserved. According to one embodiment of the present disclosure, a TXS Query may be indicated based on one of the reserved values ​​of the Trigger Type subfield. For example, Table 4 may be modified as in Table 5.

[0271] [Table 5]

[0272]

[0273] Although the value 9 of the Trigger Type subfield is exemplified as indicating TXS Query, this is only an example, and other values ​​may be defined to indicate TXS Query.

[0274] According to one embodiment of the present disclosure, a TF indicating a TXS Query in the Trigger Type subfield may include a TXOP information subfield, a Sharing condition subfield, and a Query information subfield. A sharing AP may transmit a TF indicating a TXS Query in the Trigger Type subfield to an AP that can become a shared AP.

[0275] According to one embodiment of the present disclosure, TXOP information may include information about the length / bandwidth (BW) / access category (AC) of the TXOP to be shared. Sharing conditions may include conditions for using the shared TXOP (e.g., when there is LL traffic, when the DL / UL buffer length is greater than a specific length, when there is enough data to use all of the shared TXOP, etc.) and a preemption indication. Here, the condition for using the shared TXOP may be a condition for the shared AP to use the shared TXOP. Here, the preemption indication may be information indicating that the sharing AP performs a preemption operation within the shared TXOP. Through this, operations of the shared AP may be restricted so that the sharing AP can perform the preemption operation within the shared TXOP. Query information may include information about whether to request information from neighboring APs (whether to request information about neighboring APs of the shared AP transmitting the response) and TXOP duration restrict. Information about the TXOP duration restrict may be included in the TXOP information subfield as described above. Information about the TXOP duration restrict may be information about the TXOP limit of the shared AP described above (information about the TXOP duration that the shared AP can use at one time within the shared TXOP. Information about the maximum value of the TXOP of the shared AP).

[0276] According to one embodiment of the present disclosure, a TXS Response may be transmitted in response to a TF indicating a TXS Query. The TXS Response may include a Requesting TXOP subfield and an AP information subfield. The Requesting TXOP may request TXOP sharing. The Requesting TXOP may include information on whether a shared TXOP is used, a TXOP length / bandwidth that the shared AP intends to occupy, and the like. For example, the shared AP may transmit the TXOP length that it intends to occupy within the length of the TXOP transmitted from the shared AP. The shared AP may transmit the bandwidth that it intends to occupy within the bandwidth transmitted from the shared AP. The shared AP may share the TXOP based on the TXOP length / bandwidth information transmitted by the shared AP. The AP information may include AP information necessary for TXOP sharing in addition to the information transmitted in the Requesting TXOP. For example, it may include Target Beacon Transmission Time (TBTT), Target wake time (TWT), and a list of neighbor APs. Additionally, it may include a valid timer, which is information about the time when AP information is valid.

[0277] Methods 1 to 4 according to an embodiment of the present disclosure may be applied in combination, at least in part. For example, according to Method 1, information indicating whether preemption is allowed / possible (whether to perform a C-TDMA operation in which preemption is allowed) within a shared TXOP of a shared AP may be indicated, and according to at least one of Methods 2 to 4, information regarding a TXOP limitation of the shared AP may be indicated.

[0278] FIG. 19 illustrates an example of the operation of a sharing AP according to one embodiment of the present disclosure. The flowchart of FIG. 19 illustrates an exemplary method that may be implemented according to the principles of the present disclosure, and various modifications may be made to the method illustrated in the flowchart. For example, although illustrated as a series of steps, the various steps in each drawing may overlap, occur in parallel, occur in different orders, or occur multiple times. In other examples, steps may be omitted or replaced with other steps.

[0279] Referring to FIG. 19, in operation 1901 according to one embodiment of the present disclosure, the sharing AP may negotiate with the shared AP about the TXOP interval that can be transmitted at one time and whether the sharing AP can preempt. The sharing AP may transmit configuration information for the preemption operation of the sharing AP in C-TDMA according to one embodiment of the present disclosure. The configuration information may include configuration information for the preemption operation of the sharing AP in C-TDMA. The control message may include information about the TXOP limitation of the shared AP (information about the TXOP interval that the shared AP can use at one time within the shared TXOP. Information about the maximum value of the TXOP of the shared AP).

[0280] In operation 1903 according to one embodiment of the present disclosure, the sharing AP can transmit a first message (control frame (e.g., MU-RTS TXS TF. Control frame for TXOP sharing)) for sharing a TXOP.

[0281] In operation 1905 according to one embodiment of the present disclosure, the sharing AP may generate a message to be transmitted. The sharing AP may obtain / generate data to be transmitted (e.g., LL data) according to a preemption.

[0282] In operation 1907 according to one embodiment of the present disclosure, the sharing AP can identify / detect when preemption is possible. The sharing AP can determine when preemption is possible based on a specific frame received from the shared AP.

[0283] In operation 1909 according to one embodiment of the present disclosure, the sharing AP can transmit data. The sharing AP can transmit data through preemption depending on when preemption is possible.

[0284] In operation 1911 according to one embodiment of the present disclosure, the sharing AP may determine whether re-transfer of TXOP is required. If re-transfer is required, the sharing AP may not transmit data for a specific time interval (e.g., PIFS) as an implicit instruction, as in operation 1913 according to one embodiment of the present disclosure. Alternatively, if re-transfer is required, the sharing AP may transmit a second message for TXOP sharing (control frame (e.g., MU-RTS TXS TF. Control frame for TXOP sharing)) as an explicit instruction, as in operation 1915 according to one embodiment of the present disclosure. If re-transfer is not required, the operation may be terminated.

[0285] For more specific details on the operation of the sharing AP according to one embodiment of the present disclosure described above, reference may be made to the description of various embodiments of the present disclosure described above.

[0286] FIG. 20 illustrates an example of the operation of a shared AP according to one embodiment of the present disclosure. The flowchart of FIG. 20 illustrates an exemplary method that may be implemented according to the principles of the present disclosure, and various modifications may be made to the method illustrated in the flowchart. For example, although illustrated as a series of steps, various steps in each drawing may overlap, occur in parallel, occur in different orders, or occur multiple times. In other examples, steps may be omitted or replaced with other steps.

[0287] Referring to FIG. 20, in operation 2001 according to an embodiment of the present disclosure, a shared AP may negotiate with the shared AP about a TXOP section that can be transmitted at one time and whether preemption of the shared AP is possible. The shared AP may receive configuration information for a preemption operation of the shared AP in C-TDMA according to an embodiment of the present disclosure. The configuration information may include configuration information for a preemption operation of the shared AP in C-TDMA. The control message may include information about a TXOP limitation of the shared AP (information about a TXOP section that the shared AP can use at one time within the shared TXOP. Information about a maximum value of the TXOP of the shared AP).

[0288] In operation 2003 according to one embodiment of the present disclosure, the shared AP may receive a first message (control frame (e.g., MU-RTS TXS TF. Control frame for TXOP sharing)) for sharing a TXOP.

[0289] In operation 2005 according to one embodiment of the present disclosure, a shared AP can perform transmission within a limited transmission interval within a shared TXOP. The limited transmission interval can correspond to a TXOP limitation of the shared AP received during a consultation process with the shared AP.

[0290] In operation 2007 according to one embodiment of the present disclosure, the shared AP may not perform transmission for a specific interval (e.g., PIFS) after performing transmission.

[0291] In operation 2009 according to one embodiment of the present disclosure, the shared AP can determine whether a transmission from the sharing AP has been detected / received during the specific interval. If a transmission from the sharing AP has not been detected, transmission can be performed again within the limited transmission interval in operation 2005 according to one embodiment of the present disclosure.

[0292] If a transmission from the sharing AP is detected, in operation 2011 according to an embodiment of the present disclosure, the shared AP may determine whether the shared TXOP is exhausted / expired. For example, if no transmission from the sharing AP is detected for a specific time interval (e.g., PIFS) as an implicit instruction as in operation 2013 according to an embodiment of the present disclosure, and if a second message for TXOP sharing (control frame (e.g., control frame for MU-RTS TXS TF. TXOP sharing)) is received as an explicit instruction, it may be a case that the shared TXOP is not exhausted / expired, in which case the transmission may be performed again within the limited transmission interval in operation 2005 according to an embodiment of the present disclosure. If the shared TXOP is exhausted, the operation may be terminated.

[0293] For more specific details on the operation of the shared AP according to one embodiment of the present disclosure described above, reference may be made to the description of various embodiments of the present disclosure described above.

[0294] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0295] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of the present disclosure.

[0296] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage device, compact disc ROM (CD-ROM), digital versatile discs (DVDs) or other forms of optical storage device, magnetic cassette. Or, they may be stored in a memory configured as a combination of some or all of these. In addition, each configuration memory may be included in multiple numbers.

[0297] Additionally, the program may be stored on an attachable storage device that is accessible via a communication network, such as the Internet, an intranet, a local area network (LAN), a wide local area network (WLAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device implementing an embodiment of the present disclosure via an external port. Additionally, a separate storage device on the communication network may be connected to a device implementing an embodiment of the present disclosure.

[0298] In the specific embodiments of the present disclosure described above, components included in one embodiment are expressed singularly or plurally, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in plural may be composed of singular elements, or components expressed in singular may be composed of plural elements.

[0299] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are merely specific examples to easily explain the technical content of the present disclosure and facilitate understanding of the present disclosure, and are not intended to limit the scope of the present disclosure. In other words, it will be apparent to those skilled in the art to which the present disclosure pertains that other modifications based on the technical concept of the present disclosure are possible. Furthermore, each of the above embodiments can be combined and operated as needed.

[0300] Meanwhile, the order of description in the drawings explaining the method of the present disclosure does not necessarily correspond to the order of execution, and the order of precedence may be changed or executed in parallel.

[0301] Alternatively, the drawings illustrating the method of the present disclosure may omit some components and include only some components without detracting from the essence of the present disclosure.

[0302] In addition, the method of the present disclosure may be implemented by combining some or all of the contents included in each embodiment within a scope that does not harm the essence of the present disclosure.

[0303] Various embodiments of the present disclosure have been described above. The foregoing description of the present disclosure is for illustrative purposes only, and the embodiments of the present disclosure are not limited to the disclosed embodiments. Those skilled in the art will appreciate that the present disclosure can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present disclosure. The scope of the present disclosure is indicated by the claims described below rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present disclosure.

Claims

1. In a method performed by a first AP (access point) in a wireless LAN (local access network), A step of transmitting a first setting related to allowing preemption of the first AP within a transmission opportunity (TXOP) to be shared by the first AP; A step of identifying data to be transmitted within a shared TXOP that is at least a portion of a TXOP of the first AP, wherein the shared TXOP is shared for a second AP; and A method comprising the step of transmitting the data based on the above preemption.

2. In paragraph 1, If it is identified that the transmission of the second AP within the shared TXOP starts with a control frame, the step of transmitting the data is: A step of identifying a transmission section of continuous transmission of the second AP based on the control frame; When an ACK (acknowledgement) corresponding to the transmission section is identified, a step of transmitting the data after a short inter frame space (SIFS) from the ACK; and A method comprising the step of transmitting the data after SIFS from the end of the transmission interval when an ACK corresponding to the transmission interval is not identified.

3. In paragraph 1, If it is identified that the transmission of the second AP within the shared TXOP starts with a data frame, the step of transmitting the data is: When an ACK corresponding to the data frame is identified, a step of transmitting the data after SIFS from the ACK; and If an ACK corresponding to the data frame is not identified, a step of transmitting the data after 2*SIFS + ACK duration from the end point of the most recently received data frame before transmitting the data is included. The above ACK interval is determined based on the minimum value among the values ​​of the predefined data rate, The end point of the above data frame is: A method wherein the data frame is identified based on a PHY (physical layer) header, a MAC (medium access control) header, or energy detection.

4. In paragraph 1, A step of transmitting a second setting related to a maximum transmission duration within the shared TXOP, The transmission interval of the continuous transmission of the second AP within the shared TXOP is limited to less than or equal to the maximum transmission interval, A step of transmitting a first message for sharing the shared TXOP to the second AP, The above first setting is transmitted via the above first message, or At least one of the first setting and the second setting is transmitted through an exchange of setting information for coordinated time division multiplexing access (C-TDMA) related to the shared TXOP, wherein the exchange of setting information is performed before transmission of the first message, or A method wherein at least one of the first setting and the second setting is transmitted via a control message different from the first message, wherein transmission of the control message is performed before transmission of the first message.

5. In paragraph 1, If the shared TXOP has not expired after transmitting the data, no transmission is performed for a specific time interval after transmitting the data, or a second message is transmitted to re-share the shared TXOP. A method wherein the specific time interval is greater than SIFS, and the transmission of the second AP within the shared TXOP is based on the specific time interval.

6. In the first AP (access point) of a wireless LAN (local access network), Transmitter and receiver; and A processor connected to the transceiver, the processor comprising: Transmitting a first setting related to allowing preemption of the first AP within a transmission opportunity (TXOP) by the first AP; Identifying data to be transmitted within a shared TXOP that is at least a portion of the TXOP of the first AP, wherein the shared TXOP is shared for the second AP; and A first AP configured to transmit the data based on the above preemption.

7. In paragraph 6, If it is identified that the transmission of the second AP within the shared TXOP starts with a control frame, the processor: Based on the control frame, identify the transmission section of the continuous transmission of the second AP; If an ACK (acknowledgement) corresponding to the above transmission section is identified, the data is transmitted after a short inter frame space (SIFS) from the ACK; and A first AP configured to transmit the data after SIFS from the end of the transmission interval if an ACK corresponding to the transmission interval is not identified.

8. In paragraph 6, If the processor identifies that the transmission of the second AP within the shared TXOP begins with a data frame, the processor: If an ACK corresponding to the above data frame is identified, the data is transmitted after SIFS from the ACK; and If the ACK corresponding to the data frame is not identified, the data is set to be transmitted after 2*SIFS + ACK duration from the end point of the most recently received data frame before transmission of the data. The above ACK interval is determined based on the minimum value among the values ​​of the predefined data rate, The end point of the above data frame is: A first AP identified based on a PHY (physical layer) header of the data frame, identified based on a MAC (medium access control) header of the data frame, or identified based on energy detection.

9. In paragraph 6, The processor is configured to transmit a second setting relating to a maximum transmission duration within the shared TXOP, The transmission interval of the continuous transmission of the second AP within the shared TXOP is limited to less than or equal to the maximum transmission interval, The processor is configured to transmit a first message to the second AP for sharing the shared TXOP, The above first setting is transmitted via the above first message, or At least one of the first setting and the second setting is transmitted through an exchange of setting information for coordinated time division multiplexing access (C-TDMA) related to the shared TXOP, wherein the exchange of setting information is performed before transmission of the first message, or A first AP, wherein at least one of the first setting and the second setting is transmitted via a control message different from the first message, wherein transmission of the control message is performed before transmission of the first message.

10. In paragraph 6, If the shared TXOP has not expired after transmitting the data, no transmission is performed for a specific time interval after transmitting the data, or a second message is transmitted to re-share the shared TXOP. The above specific time interval is greater than SIFS, and the transmission of the second AP within the shared TXOP is based on the above specific time interval, the first AP.

11. In a method performed by a second AP (access point) in a wireless LAN (local access network), A step of receiving a first setting related to allowing preemption of the first AP within a transmission opportunity (TXOP) to be shared from the first AP; A step of identifying a shared TXOP that is at least a portion of the TXOP of the first AP; and A method comprising the step of performing transmission based on a specific time interval within the shared TXOP, wherein the specific time interval is greater than a short inter frame space (SIFS).

12. In paragraph 11, comprising a step of receiving a second setting related to a maximum transmission duration within the shared TXOP; The transmission interval of the continuous transmission of the second AP within the shared TXOP is limited to less than or equal to the maximum transmission interval, comprising a step of receiving a first message for the shared TXOP from the first AP; The above first setting is received via the above first message, or At least one of the first setting and the second setting is received through setting information exchange for coordinated time division multiplexing access (C-TDMA) related to the shared TXOP, wherein the setting information exchange is performed before receiving the first message, or A method wherein at least one of the first setting and the second setting is received via a control message different from the first message, wherein reception of the control message is performed before reception of the first message.

13. In paragraph 11, After the transmission of data based on the preemption of the first AP is identified within the specific time interval, if the shared TXOP has not expired, a step of performing transmission based on the specific time interval within the remaining time of the shared TXOP is included. A method in which the shared TXOP does not expire, wherein no transmission of data from the first AP is identified during the specific time interval after transmission of data based on the preemption, or a second message is received indicating that the shared TXOP is re-shared.

14. In the second AP (access point) of a wireless LAN (local access network), Transmitter and receiver; and A processor connected to the transceiver, the processor comprising: Receive a first setting relating to preemption of the first AP being allowed within a transmission opportunity (TXOP) to be shared from the first AP; Identifying a shared TXOP that is at least a portion of the TXOP of the first AP; and A second AP configured to perform transmission based on a specific time interval within the shared TXOP, wherein the specific time interval is greater than a short inter frame space (SIFS).

15. In paragraph 14, The processor is configured to receive a second setting relating to a maximum transmission duration within the shared TXOP, The transmission interval of the continuous transmission of the second AP within the shared TXOP is limited to less than or equal to the maximum transmission interval, The processor is configured to receive a first message for the shared TXOP from the first AP, The above first setting is received via the above first message, or At least one of the first setting and the second setting is received through setting information exchange for coordinated time division multiplexing access (C-TDMA) related to the shared TXOP, wherein the setting information exchange is performed before receiving the first message, or A second AP, wherein at least one of the first setting and the second setting is received via a control message different from the first message, wherein reception of the control message is performed before reception of the first message.

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