Method and apparatus for channel access in wireless LAN system

Abstract

Various embodiments of the present disclosure relate to a method and a device for channel access in a wireless local access network (LAN) system. The method performed by the device in a wireless LAN system, according to one embodiment of the present disclosure, may comprise the steps of: initiating a transmission opportunity (TXOP) for non-primary channel access (NPCA) on an NPCA primary channel for NPCA on the basis of enhanced distributed channel access (EDCA); setting a trigger frame, the trigger frame including a Special User Info field and B37 bit of the Special User Info field including a 1-bit indication related to the NPCA; and transmitting the trigger frame on the basis of the NPCA primary channel after initiating the TXOP for the NPCA.

Description

Method and device for channel access in a wireless LAN system

[0001] The present disclosure relates generally to a wireless LAN system, and more particularly to a method and device for channel access in a wireless LAN system.

[0002] A wireless local area network (WLAN), also known as Wireless Fidelity (Wi-Fi), is a network that allows users to access the Internet via mobile devices and laptops 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 may provide a method and device for channel access in a wireless LAN system.

[0006] 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.

[0007] According to one embodiment of the present disclosure, a method performed by an access point (AP) in a wireless LAN (local access network) system can be provided.

[0008] According to one embodiment of the present disclosure, the method may include identifying a transmission associated with an overlapping basic service set (OBSS) on a primary channel.

[0009] According to one embodiment of the present disclosure, the method may include a step of setting an NPCA time interval for non-primary channel access (NPCA).

[0010] According to one embodiment of the present disclosure, the end point of the NPCA time interval can be set based on a predefined tail latency.

[0011] According to one embodiment of the present disclosure, the method may include a step of acquiring a non-primary channel (NPC) transmission opportunity (TXOP) within the NPCA time interval based on a channel access procedure in a specific channel included in the NPCH (non-primary channel).

[0012] According to one embodiment of the present disclosure, when the transmission related to the OBSS is an OBSS PPDU (physical layer protocol data unit), a section of the OBSS PPDU can be identified based on a preamble of the OBSS PPDU.

[0013] According to one embodiment of the present disclosure, when the interval of the OBSS PPDU is greater than a predefined threshold, the NPCA time interval is set, and the end time of the NPCA time interval can be set to be before the end time of the interval of the OBSS PPDU by the predefined tail delay time.

[0014] According to one embodiment of the present disclosure, the start time of the NPCA time interval may be set after reception of the preamble of the OBSS PPDU.

[0015] According to one embodiment of the present disclosure, when a transmission related to the OBSS is an OBSS ICF (initial control frame) and an OBSS ICR (initial control response) is identified after a short inter frame space (SIFS) from the OBSS ICF, or when the transmission related to the OBSS is the OBSS ICR: an end time of the NPCA time interval may be set to be before the predefined tail delay time an end time of a basic network allocation vector (NAV) corresponding to the primary channel, and a start time of the NPCA time interval may be set after reception of the OBSS ICR or after the specific channel is identified as idle for a priority inter frame space (PIFS) from reception of the OBSS ICR.

[0016] According to one embodiment of the present disclosure, if a transmission related to the OBSS is an OBSS ICF and an OBSS ICR is not identified after SIFS from the OBSS ICF and an OBSS PPDU is identified within a certain time interval, an end time of the NPCA time interval is set to be before the predefined tail delay time than an end time of a basic NAV corresponding to the primary channel, and a start time of the NPCA time interval is set after reception of a preamble of the OBSS PPDU, and if the OBSS PPDU is not identified within the certain time interval, the NPCA time interval is not set and the NPCA can be terminated.

[0017] According to one embodiment of the present disclosure, the NPC TXOP may be set to be greater than or equal to a predefined minimum NPC TXOP time interval.

[0018] According to one embodiment of the present disclosure, if it is identified that acquisition of a next NPC TXOP greater than or equal to the predefined minimum NPC TXOP time interval is possible based on the remaining time interval of the NPCA time interval after the end of the NPC TXOP, the next NPC TXOP can be acquired based on a channel access procedure in the specific channel.

[0019] According to one embodiment of the present disclosure, if it is determined that acquisition of the next NPC TXOP longer than the predefined minimum NPC TXOP time interval is impossible based on the remaining time interval of the NPCA time interval after the termination of the NPC TXOP, the AP may terminate the NPCA and return to the primary channel.

[0020] According to one embodiment of the present disclosure, the predefined tail delay time may be related to the time for returning to the primary channel after the termination of the NPCA.

[0021] According to one embodiment of the present disclosure, when the transmission related to the OBSS is an OBSS PPDU, the NPC TXOP can be acquired as the remaining time interval of the NPCA time interval.

[0022] According to one embodiment of the present disclosure, the method may include: identifying whether an OBSS PPDU is detected on the primary channel during a predefined time interval when a transmission associated with the OBSS includes at least one of an OBSS ICF or an OBSS ICR; and identifying whether a time interval of the detected OBSS PPDU is greater than or equal to a predefined minimum NPC TXOP time interval when the OBSS PPDU is detected during the predefined time interval.

[0023] According to one embodiment of the present disclosure, if the time interval of the detected OBSS PPDU is greater than or equal to the predefined minimum NPC TXOP time interval, the NPC TXOP can be obtained as the time interval of the detected OBSS PPDU.

[0024] According to one embodiment of the present disclosure, the method may include a step of transmitting a trigger frame including information about the AP performing an operation related to the NPCA.

[0025] According to one embodiment of the present disclosure, information about the AP performing an operation related to the NPCA may be 1-bit information.

[0026] According to one embodiment of the present disclosure, an access point (AP) of a wireless local access network (LAN) system may be provided.

[0027] According to one embodiment of the present disclosure, the AP may include a transceiver; and a processor connected to the transceiver.

[0028] According to one embodiment of the present disclosure, the processor may be configured to identify a transmission associated with an overlapping basic service set (OBSS) on a primary channel.

[0029] According to one embodiment of the present disclosure, the processor may be configured to set an NPCA time interval for non-primary channel access (NPCA).

[0030] According to one embodiment of the present disclosure, the end point of the NPCA time interval can be set based on a predefined tail latency.

[0031] According to one embodiment of the present disclosure, the processor may be configured to acquire a non-primary channel (NPC) transmission opportunity (TXOP) within the NPCA time interval based on a channel access procedure in a specific channel included in the NPCH (non-primary channel).

[0032] According to one embodiment of the present disclosure, when the transmission related to the OBSS is an OBSS PPDU (physical layer protocol data unit), a section of the OBSS PPDU can be identified based on a preamble of the OBSS PPDU.

[0033] According to one embodiment of the present disclosure, when the interval of the OBSS PPDU is greater than a predefined threshold, the NPCA time interval is set, and the end time of the NPCA time interval can be set to be before the end time of the interval of the OBSS PPDU by the predefined tail delay time.

[0034] According to one embodiment of the present disclosure, the start time of the NPCA time interval may be set after reception of the preamble of the OBSS PPDU.

[0035] According to one embodiment of the present disclosure, when a transmission related to the OBSS is an OBSS ICF (initial control frame) and an OBSS ICR (initial control response) is identified after a short inter frame space (SIFS) from the OBSS ICF, or when the transmission related to the OBSS is the OBSS ICR: an end time of the NPCA time interval may be set to be before the predefined tail delay time an end time of a basic network allocation vector (NAV) corresponding to the primary channel, and a start time of the NPCA time interval may be set after reception of the OBSS ICR or after the specific channel is identified as idle for a priority inter frame space (PIFS) from reception of the OBSS ICR.

[0036] According to one embodiment of the present disclosure, if a transmission related to the OBSS is an OBSS ICF and an OBSS ICR is not identified after SIFS from the OBSS ICF and an OBSS PPDU is identified within a certain time interval, an end time of the NPCA time interval is set to be before the predefined tail delay time than an end time of a basic NAV corresponding to the primary channel, and a start time of the NPCA time interval is set after reception of a preamble of the OBSS PPDU, and if the OBSS PPDU is not identified within the certain time interval, the NPCA time interval is not set and the NPCA can be terminated.

[0037] According to one embodiment of the present disclosure, the NPC TXOP may be set to be greater than or equal to a predefined minimum NPC TXOP time interval.

[0038] According to one embodiment of the present disclosure, if it is identified that acquisition of a next NPC TXOP greater than or equal to the predefined minimum NPC TXOP time interval is possible based on the remaining time interval of the NPCA time interval after the end of the NPC TXOP, the next NPC TXOP can be acquired based on a channel access procedure in the specific channel.

[0039] According to one embodiment of the present disclosure, if it is determined that acquisition of the next NPC TXOP longer than the predefined minimum NPC TXOP time interval is impossible based on the remaining time interval of the NPCA time interval after the termination of the NPC TXOP, the AP may terminate the NPCA and return to the primary channel.

[0040] According to one embodiment of the present disclosure, the predefined tail delay time may be related to the time for returning to the primary channel after the termination of the NPCA.

[0041] According to one embodiment of the present disclosure, when the transmission related to the OBSS is an OBSS PPDU, the NPC TXOP can be acquired as the remaining time interval of the NPCA time interval.

[0042] According to one embodiment of the present disclosure, the processor may be configured to identify whether an OBSS PPDU is detected on the primary channel during a predefined time interval when a transmission associated with the OBSS includes at least one of an OBSS ICF or an OBSS ICR; and, when the OBSS PPDU is detected during the predefined time interval, identify whether a time interval of the detected OBSS PPDU is greater than or equal to a predefined minimum NPC TXOP time interval.

[0043] According to one embodiment of the present disclosure, if the time interval of the detected OBSS PPDU is greater than or equal to the predefined minimum NPC TXOP time interval, the NPC TXOP can be obtained as the time interval of the detected OBSS PPDU.

[0044] According to one embodiment of the present disclosure, the processor may be configured to transmit a trigger frame including information about the AP performing an operation related to the NPCA.

[0045] According to one embodiment of the present disclosure, information about the AP performing an operation related to the NPCA may be 1-bit information.

[0046] According to one embodiment of the present disclosure, a method performed by a STA (station) in a wireless LAN (local access network) system can be provided.

[0047] According to one embodiment of the present disclosure, the method may include identifying a transmission associated with an overlapping basic service set (OBSS) on a primary channel.

[0048] According to one embodiment of the present disclosure, the method may include a step of setting an NPCA time interval for non-primary channel access (NPCA).

[0049] According to one embodiment of the present disclosure, the end point of the NPCA time interval can be set based on a predefined tail latency.

[0050] According to one embodiment of the present disclosure, the method may include receiving a first trigger frame from an access point (AP) via a non-primary channel (NPCH), the first trigger frame including information that the AP performs an operation related to the NPCA.

[0051] According to one embodiment of the present disclosure, information about the AP performing an operation related to the NPCA may be 1-bit information.

[0052] According to one embodiment of the present disclosure, the method may include receiving a second trigger frame from the AP via the NPCH.

[0053] According to one embodiment of the present disclosure, the method may include transmitting an uplink (UL) trigger-based (TB) physical layer protocol data unit (PPDU) to the AP through the NPCH based on the second trigger frame.

[0054] According to one embodiment of the present disclosure, a STA (station) of a wireless LAN (local access network) system can be provided.

[0055] According to one embodiment of the present disclosure, the STA may include a transceiver; and a processor connected to the transceiver.

[0056] According to one embodiment of the present disclosure, the processor may be configured to identify a transmission associated with an overlapping basic service set (OBSS) on a primary channel.

[0057] According to one embodiment of the present disclosure, the processor may be configured to set an NPCA time interval for non-primary channel access (NPCA).

[0058] According to one embodiment of the present disclosure, the processor may set the end point of the NPCA time interval based on a predefined tail latency.

[0059] According to one embodiment of the present disclosure, the processor may be configured to receive a first trigger frame from an access point (AP) via a non-primary channel (NPCH), the first trigger frame including information that the AP performs an operation related to the NPCA.

[0060] According to one embodiment of the present disclosure, the information about the processor performing an operation related to the NPCA by the AP may be 1-bit information.

[0061] According to one embodiment of the present disclosure, the processor may be configured to receive a second trigger frame from the AP via the NPCH.

[0062] According to one embodiment of the present disclosure, the processor may be configured to transmit an uplink (UL) trigger-based (TB) physical layer protocol data unit (PPDU) to the AP through the NPCH based on the second trigger frame.

[0063] According to one embodiment of the present disclosure, a method performed by a device in a wireless local access network (LAN) system may be provided.

[0064] According to one embodiment of the present disclosure, the method may include the steps of: initiating a transmission opportunity (TXOP) for a non-primary channel access (NPCA) on an NPCA primary channel based on enhanced distributed channel access (EDCA); setting a trigger frame, the trigger frame including a Special User Info field and a B37 bit of the Special User Info field including a 1-bit indication related to the NPCA; and transmitting the trigger frame based on the NPCA primary channel after initiating the TXOP for the NPCA.

[0065] According to one embodiment of the present disclosure, the 1-bit instruction may be set to indicate that the device performs an operation related to the NPCA.

[0066] According to one embodiment of the present disclosure, the method may include setting an operation time interval for the NPCA based on a time required to switch from the NPCA primary channel to a primary channel for a basic service set (BSS) corresponding to the device.

[0067] According to one embodiment of the present disclosure, after identifying a physical layer protocol data unit (PPDU) or TXOP related to a BSS different from the BSS corresponding to the device on a primary channel for the BSS corresponding to the device, an operation time interval for the NPCA is set, the time interval of the PPDU related to the different BSS is equal to or greater than a preset threshold, and the preset threshold may be set equal to or greater than the sum of (i) a transmission time for an exchange between a specific control frame and a response and (ii) a transmission time for an exchange between specific data and at least one of an ACK (acknowledgement) or a block ACK.

[0068] According to one embodiment of the present disclosure, when a TXOP associated with the other BSS is identified, an operation time interval for the NPCA is set after detecting a preamble of a first PPDU received on the primary channel for the BSS corresponding to the device after a control frame exchange including an ICF corresponding to the PHY-RXEND.indication primitive is received on the primary channel for the BSS corresponding to the device within a specific time interval after receiving a PHY-RXEND.indication primitive corresponding to an ICF on the primary channel for the BSS corresponding to the device, and the specific time interval may be a time interval corresponding to NAVTimeout.

[0069] According to one embodiment of the present disclosure, the TXOP for the NPCA is included in the operation time interval for the NPCA, and the time interval of the TXOP for the NPCA is equal to or greater than a preset minimum time interval, and when it is determined that acquisition of a next TXOP for the NPCA having a time interval equal to or greater than the preset minimum time interval is possible on the NPCA primary channel based on the remaining time interval of the operation time interval for the NPCA after the end of the TXOP for the NPCA, the next TXOP for the NPCA is acquired based on the EDCA, and when it is determined that acquisition of a next TXOP for the NPCA having a time interval equal to or greater than the preset minimum time interval is impossible on the NPCA primary channel based on the remaining time interval of the operation time interval for the NPCA after the end of the TXOP for the NPCA, the NPCA primary channel can be switched to a primary channel for a BSS corresponding to the device. there is.

[0070] According to one embodiment of the present disclosure, the trigger frame includes an ICF transmitted first after initiation of a TXOP for the NPCA, the first transmitted ICF including a CS (carrier sense) required subfield, and an ICR may be instructed to be transmitted in response to the first transmitted ICF when the NPCA primary channel is identified as idle based on the CS required subfield.

[0071] According to one embodiment of the present disclosure, the device may be an NPCA AP (access point) supporting the NPCA.

[0072] According to one embodiment of the present disclosure, a device of a wireless LAN (local access network) system may be provided.

[0073] According to one embodiment of the present disclosure, the device includes a transceiver; and a processor connected to the transceiver, wherein the processor is configured to: initiate a transmission opportunity (TXOP) for a non-primary channel access (NPCA) on an NPCA primary channel based on enhanced distributed channel access (EDCA); establish a trigger frame, the trigger frame including a Special User Info field and a B37 bit of the Special User Info field including a 1-bit indication related to the NPCA; and transmit the trigger frame based on the NPCA primary channel after initiating the TXOP for the NPCA.

[0074] According to one embodiment of the present disclosure, the 1-bit instruction may be set to indicate that the device performs an operation related to the NPCA.

[0075] According to one embodiment of the present disclosure, the processor may be configured to set an operating time interval for the NPCA based on a time required to switch from the NPCA primary channel to a primary channel for a basic service set (BSS) corresponding to the device.

[0076] According to one embodiment of the present disclosure, after identifying a physical layer protocol data unit (PPDU) or TXOP related to a BSS different from the BSS corresponding to the device on a primary channel for the BSS corresponding to the device, an operation time interval for the NPCA is set, the time interval of the PPDU related to the different BSS is equal to or greater than a preset threshold, and the preset threshold may be set equal to or greater than the sum of (i) a transmission time for an exchange between a specific control frame and a response and (ii) a transmission time for an exchange between specific data and at least one of an ACK (acknowledgement) or a block ACK.

[0077] According to one embodiment of the present disclosure, when a TXOP associated with the other BSS is identified, an operation time interval for the NPCA is set after detecting a preamble of a first PPDU received on the primary channel for the BSS corresponding to the device after a control frame exchange including an ICF corresponding to the PHY-RXEND.indication primitive is received on the primary channel for the BSS corresponding to the device within a specific time interval after receiving a PHY-RXEND.indication primitive corresponding to an ICF on the primary channel for the BSS corresponding to the device, and the specific time interval may be a time interval corresponding to NAVTimeout.

[0078] According to one embodiment of the present disclosure, the TXOP for the NPCA is included in the operation time interval for the NPCA, and the time interval of the TXOP for the NPCA is equal to or greater than a preset minimum time interval, and when it is determined that acquisition of a next TXOP for the NPCA having a time interval equal to or greater than the preset minimum time interval is possible on the NPCA primary channel based on the remaining time interval of the operation time interval for the NPCA after the end of the TXOP for the NPCA, the next TXOP for the NPCA is acquired based on the EDCA, and when it is determined that acquisition of a next TXOP for the NPCA having a time interval equal to or greater than the preset minimum time interval is impossible on the NPCA primary channel based on the remaining time interval of the operation time interval for the NPCA after the end of the TXOP for the NPCA, the NPCA primary channel can be switched to a primary channel for a BSS corresponding to the device. there is.

[0079] According to one embodiment of the present disclosure, the trigger frame includes an ICF transmitted first after the initiation of a TXOP for the NPCA, the first transmitted ICF including a CS (carrier sense) required subfield, and when the NPCA primary channel is identified as idle based on the CS required subfield, an ICR that is a response to the first transmitted ICF can be instructed to be transmitted.

[0080] 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.

[0081] Various embodiments of the present disclosure may provide a method and device for channel access in a wireless LAN system.

[0082] 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.

[0083] 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.

[0084] FIG. 1 is a diagram illustrating an example of a wireless communication network to which various embodiments of the present disclosure can be applied.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] FIG. 6 is a diagram illustrating an example of NAV settings to which various embodiments of the present disclosure can be applied.

[0090] FIG. 7 is a diagram illustrating an example of a TXOP to which various embodiments of the present disclosure can be applied.

[0091] FIG. 8 is a diagram illustrating an example of a channel connection to which various embodiments of the present disclosure can be applied.

[0092] FIG. 9 is a diagram illustrating an example of a method for setting an NPCA section according to one embodiment of the present disclosure.

[0093] FIG. 10 is a drawing for explaining an example of an NPCA operation notification message format according to one embodiment of the present disclosure.

[0094] FIG. 11 is a drawing for explaining an example of an NPCA operation notification message format according to one embodiment of the present disclosure.

[0095] FIG. 12 is a diagram illustrating an example of an NPCA operation notification message format according to one embodiment of the present disclosure.

[0096] FIG. 13 is a drawing for explaining an example of an NPCA operation notification message format according to one embodiment of the present disclosure.

[0097] FIG. 14 is a diagram illustrating an example of the operation of an NPCA AP related to an NPC TXOP according to one embodiment of the present disclosure.

[0098] FIG. 15 is a diagram illustrating an example of the operation of an NPCA AP / NPCA STA related to an NPC TXOP according to one embodiment of the present disclosure.

[0099] FIG. 16 is a diagram illustrating an example of an NPCA procedure according to one embodiment of the present disclosure.

[0100] FIG. 17 is a diagram illustrating an example of NPC TXOP operation within an NPCA according to one embodiment of the present disclosure.

[0101] FIG. 18 is a diagram illustrating an example of an operation related to an NPC TXOP within an NPCA operation section according to one embodiment of the present disclosure.

[0102] FIG. 19 is a diagram illustrating an example of an operation related to an NPC TXOP within an NPCA operation section according to one embodiment of the present disclosure.

[0103] FIG. 20 is a diagram illustrating an example of an operation related to an NPC TXOP within an NPCA operation section according to one embodiment of the present disclosure.

[0104] FIG. 21 is a diagram illustrating an example of an operation related to an NPC TXOP within an NPCA operation section according to one embodiment of the present disclosure.

[0105] FIG. 22 is a diagram illustrating an example of an operation related to an NPC TXOP within an NPCA operation section according to one embodiment of the present disclosure.

[0106] FIG. 23 is a diagram illustrating an example of an operation related to an NPC TXOP within an NPCA operation section according to one embodiment of the present disclosure.

[0107] FIG. 24 is a diagram illustrating an example of an operation related to an NPC TXOP within an NPCA operation section according to one embodiment of the present disclosure.

[0108] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings.

[0109] 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 ensure that the gist of the present disclosure is conveyed more clearly without obscuring it by omitting unnecessary explanations.

[0110] 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.

[0111] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described below in detail 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.

[0112] 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).

[0113] 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).

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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. 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).

[0118] 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.

[0119] 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.

[0120] FIG. 1 is a diagram illustrating an example of a wireless communication network to which various embodiments of the present disclosure can be applied.

[0121] 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 access point (AP) 102 and a plurality of stations (STAs) 104. Although only one AP (102) is illustrated, the wireless communication network (100) may also include a plurality of APs (102).

[0122] 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.

[0123] 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.

[0124] 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).

[0125] 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).

[0126] 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.

[0127] 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.

[0128] 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.

[0129] Additionally, the AP (102) and the STA (104) may be referred to as AP-MLD (access point multi-link device) and STA-MLD, respectively. This may mean that the AP and the STA can support multi-link operation.

[0130] Below is an example of a hierarchical structure according to the 802.11 standard.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] 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).

[0140] 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.

[0141] 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.

[0142] 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).

[0143] 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).

[0144] 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.

[0145] 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.

[0146] 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.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] 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.

[0152] 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.

[0153] 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).

[0154] 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.

[0155] 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.

[0156] 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.

[0157] 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.

[0158] 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.

[0159] Below we describe the media access control protocol provided by 802.11.

[0160] 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.

[0161] 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.

[0162] 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.

[0163] 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.

[0164] 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).

[0165] 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.

[0166] 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.

[0167] (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.

[0168] 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.

[0169] (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.

[0170] (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.

[0171] 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.

[0172] 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.

[0173] 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 can be collectively called the PLCP preamble, which is a signal for OFDM physical layer synchronization and channel estimation.

[0174] 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.

[0175] 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.

[0176] 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.

[0177] 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.

[0178] 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.

[0179] 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.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] FCS is defined as a MAC footer and is used to detect errors in MAC frames.

[0184] 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.

[0185] Below is a description of the network allocation vector (NAV) used in wireless LAN networks.

[0186] 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.

[0187] FIG. 6 is a diagram illustrating an example of NAV settings to which various embodiments of the present disclosure can be applied.

[0188] 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).

[0189] 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.

[0190] 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).

[0191] 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).

[0192] 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).

[0193] FIG. 7 is a diagram illustrating an example of a TXOP to which various embodiments of the present disclosure can be applied.

[0194] 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.

[0195] 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.

[0196] NAV can be understood as a type 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 its NAV 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.

[0197] 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.

[0198] Below, we describe the overlapping basic service set (OBSS). Existing wireless LAN networks experience significant performance degradation, including throughput, as users increase. This is because wireless LAN systems fundamentally utilize CSMA / CA, a time-division access control scheme. When a neighboring network is detected, the system divides the frequency resources in the same band by the amount of time the neighboring network is active.

[0199] Currently, there are many cases where multiple APs are operating in a specific area, and in this case, the performance of the wireless LAN network deteriorates due to overlapping coverage between APs. This is because the APs of each BSS and the STAs connected to the APs are affected by the signals of the neighboring BSS, resulting in interference by the neighboring BSS, which in turn causes a decrease in the transmission rate due to collisions between signals transmitted at the same time. BSSs that can affect signal transmission in this way (or whose coverage overlaps) can be referred to as overlapping BSSs (OBSS). To solve this problem, interference avoidance technologies that divide the bands available to each user so that they do not overlap or perform channel switching to unused channels, as well as interference alignment technologies that reduce the impact of interference even when using the same band, are being studied.

[0200] FIG. 8 is a diagram illustrating an example of channel access to which various embodiments of the present disclosure may be applied. FIG. 8 is for explaining non-primary channel access (NPCA). In FIG. 8, a wideband channel is illustrated as being composed of a 20 MHz primary channel (primary 20 MHz channel) and multiple 20 MHz secondary channels (secondary 20 MHz channels). This is for convenience of explanation and the present disclosure is not limited thereto.

[0201] A primary channel is a common channel operated by all STAs that are members of a BSS. For example, in a 20 MHz, 40 MHz, 80 MHz, 160 MHz, or 80 + 80 MHz BSS, the primary channel may be the primary 20 MHz channel.

[0202] A secondary channel is a channel associated with a primary channel and is used to create a wider channel than the primary channel. For example, in a 40 MHz, 80 MHz, 160 MHz, or 80 + 80 MHz BSS, the secondary channel may be a secondary 20 MHz channel.

[0203] According to the current 801.11 standard, for any transmission (e.g., transmission on 20 / 40 / 80 / 160 / 320MHz channels), the primary channel (primary 20MHz channel) must be idle to allow access to wideband channels larger than 20MHz. Therefore, if the primary channel is busy, the AP / STA cannot transmit on any idle secondary channel. In other words, if the primary channel is busy, no transmission can be performed on the secondary channel even if the secondary channel is idle.

[0204] For example, referring to Fig. 8(a), even if the secondary channel is available, transmission cannot be performed if the primary channel is busy.

[0205] For example, the primary channel may be busy due to interference from a 20MHz PPDU corresponding to an overlapping BSS (OBSS), in which case transmission cannot be performed even if secondary channels of 60MHz are available.

[0206] For example, the primary channel may be busy due to interference from a 40MHz PPDU corresponding to an OBSS, in which case transmission cannot be performed even if the 40MHz secondary channels are available.

[0207] That is, according to the current 801.11 standard, when the primary channel is idle, the STA can transmit packets. That is, when the primary channel is idle, the STA can perform transmission (e.g., transmission of 80MHz PPDU) using the primary channel and the secondary channel. This applies equally to the UL (uplink) transmission of the STA as well as the DL (downlink) transmission of the AP.

[0208] Therefore, the current secondary channel access mechanism (or scheme) is inefficient for wideband channels (e.g., 160MHz channel, 320MHz channel) or large bandwidth, and a better secondary channel access mechanism (or scheme) is required to fully utilize wideband channels.

[0209] Non-primary channel access (NPCA) is being discussed as a solution to the above-mentioned problems. NPCA can be triggered based on OBSS PPDUs and / or OBSS TXOPs. According to NPCA, if the primary channel is busy and the secondary channel is available, the AP / STA can transmit on the available secondary channel.

[0210] An NPCA primary channel may be defined among the secondary channels (or within the secondary channels). The NPCA primary channel may be a channel on which channel access (e.g., EDCA) is performed while the primary channel is busy. That is, the NPCA primary channel may be a 20 MHz channel on which channel access is performed while the primary channel is busy within the secondary channels. The NPCA primary channel may be referred to as an anchor channel, but the present disclosure is not limited to this specific name.

[0211] For example, referring to FIG. 8(b), when the primary channel is busy, transmission can be performed on available secondary channels.

[0212] For example, if the primary channel is busy due to interference by a 20MHz PPDU corresponding to an OBSS, the STA can transmit packets (e.g., 60MHz PPDU) on available secondary channels while the primary channel is busy. Channel access can be performed on an anchor channel within the secondary channels, thereby allowing packets to be transmitted on the secondary channels when the anchor channel is idle. This applies equally to UL transmissions of the STA as well as DL transmissions of the AP.

[0213] For example, if the primary channel is busy due to interference by a 40MHz PPDU corresponding to an OBSS, the STA can transmit packets (e.g., 40MHz PPDU) on available secondary channels while the primary channel is busy. Channel access can be performed on an anchor channel within the secondary channels, thereby allowing packets to be transmitted on the secondary channels when the anchor channel is idle. This applies equally to UL transmissions of the STA as well as DL transmissions of the AP.

[0214] In the description of one embodiment of the present disclosure, an NPCA AP may mean an AP having the capability to perform NPCA (or an AP performing / capable of performing operations related to NPCA), and an NPCA STA may mean an STA associated with an NPCA AP having the capability to perform NPCA (or an STA performing / capable of performing operations related to NPCA). Unless specifically stated otherwise, AP, NPCA AP, STA, and NPCA STA may be used interchangeably in the present disclosure.

[0215] When the OBSS initiates the OBSS TXOP, the NPCA AP and / or NPCA STA within the BSS may set BasicNAV (Basic NAV. NAV) and perform NPCA. For example, the BasicNAV may be set for the primary channel. For example, when the OBSS identifies that the OBSS has initiated the OBSS TXOP based on the RTS-CTS exchange, the NPCA AP and / or NPCA STA within the BSS may set BasicNAV and perform NPCA. Here, whether or not to perform NPCA may be identified based on a comparison between the OBSS TXOP and a specific duration threshold. For example, when the OBSS TXOP is shorter than (or less than) the specific duration threshold, NPCA may not be performed. Conversely, NPCA may be performed if the OBSS TXOP is longer than (or greater than) a certain interval threshold. This is because, if the OBSS TXOP is relatively short, it may be more advantageous to wait until the end of the OBSS TXOP than to perform an operation based on NPCA.

[0216] Secondary channels on which NPCA will operate and anchor channels (e.g., a 20 MHz anchor channel) on which channel access (e.g., EDCA) procedures will be performed within the secondary channels may be pre-configured / pre-agreed upon between NPCA APs and / or NPCA STAs within a BSS. The secondary channels on which NPCA will operate may be named NPCHs (non-primary channels), but the present disclosure is not limited to these specific names.

[0217] The operation of NPCA AP can be as follows:

[0218] An NPCA AP may not perform NPCA in a band outside of its operating bandwidth. That is, an NPCA AP may perform NPCA within its operating bandwidth.

[0219] An NPCA AP can perform NPCA if the secondary channel is idle during the PIFS interval immediately preceding the starting point of an OBSS TXOP.

[0220] If an NPCA AP has a separate NAV timer, i.e., a separate NPCH NAV timer is configured for the anchor channel, and the NPCH NAV timer has a non-zero value, the NPCA AP may not be able to initiate a TXOP within the NPCH. If an NPCA AP has a separate NAV timer, i.e., a separate NPCH NAV timer is configured for the anchor channel, and the NPBCH NAV timer is 0, the NPCA AP may initiate a TXOP within the NPCH.

[0221] An NPCA AP can perform channel access (e.g., EDCA contention) on an anchor channel where OBSS transmissions do not overlap, and the remaining channels within the NPCH (excluding the anchor channel) can be accessed by ED (energy detection). For example, if the PIFS is idle just before the backoff counter of the anchor channel expires, the remaining channels can be accessed.

[0222] The operation of NPCA STA can be as follows.

[0223] NPCA STAs can switch their operating bandwidths to perform NPCA. Unlike NPCA APs, which do not perform NPCA outside their operating bandwidth, NPCA STAs can also switch their operating bandwidths to perform NPCA. For example, NPCA STAs can perform NPCA based on AP instructions / configurations and / or by switching to predefined / promised operating bandwidths.

[0224] The NPCA capability of an STA and / or the on / off status of the NPCA capability can be established through prior information and / or message exchange. An STA and an AP can confirm whether NPCA can be performed, i.e., NPCA capability, by exchanging Probe requests and Probe responses or Association requests and Association responses. Thereafter, an AP and STA capable of performing NPCA exchange OBSS information (e.g., MAC addresses or color information of OBSS APs and STAs) visible (detected in the vicinity) to establish a list of OBSSs that are not in a hidden relationship with each other, and can perform NPCA when transmission occurs due to the OBSS. When performing NPCA, an anchor channel for performing EDCA and an NPCH capable of transmitting data including the anchor channel can be established in advance through information exchange between the NPCA AP and the NPCA STA.

[0225] 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."

[0226] According to one embodiment of the present disclosure, a method for determining whether NPCA is operating may be provided. According to one embodiment of the present disclosure, a method for setting / determining an NPCA duration may be provided.

[0227] According to one embodiment of the present disclosure, after receiving an OBSS PPDU preamble, the AP and / or STA may determine whether to operate NPCA by checking the PDDU duration. The preamble of the OBSS PPDU may include information about the time occupied by the OBSS PPDU (information about the transmission time occupied by the OBSS PPDU), and the AP and / or STA may identify / obtain the transmission time of the OBSS PPDU from the information of the preamble of the OBSS PPDU. If the transmission time of the OBSS PPDU is greater than (or equal to) a reference time, the NPCA operation may be performed. If the transmission time of the OBSS PPDU is shorter than (or equal to) the reference time, the NPCA operation may not be performed.

[0228] According to one embodiment of the present disclosure, the AP and / or STA may set / determine an NPCA interval. If it is determined that the NPCA operation is to be performed, the AP and / or STA may immediately start NPCA. That is, if the transmission time of the OBSS PPDU is greater than (or equal to) the reference time, the NPCA may immediately start. This may be understood as setting / determining the starting point of the NPCA interval. The ending point (end) of the NPCA interval may be set in consideration of the transmission time of the OBSS PPDU and tail latency. The tail latency may be the time taken to return to the primary channel after performing NPCA and / or may include the time taken to return to the primary channel after performing NPCA.

[0229] According to one embodiment of the present disclosure, if an OBSS PPDU received on a primary channel is a control frame (CF), the AP and / or STA can acquire an OBSS TXOP according to the BasicNAV rule. For example, the control frame may correspond to an initial control frame (ICF) / initial control frame response (ICR) exchange and / or a trigger-based operation. The ICF may be a frame for acquiring a TXOP, and the ICR may be understood as a response to the ICF. For example, examples of the ICF may include an RTS, a trigger frame, etc., and examples of the ICR may include a CTS, etc. When a control frame is received, the AP and / or STA may acquire an OBSS TXOP from the control frame, and the AP and / or STA may set BasicNAV. In this case, the AP and / or STA may determine whether to operate NPCA. If it is determined to perform NPCA operation, the AP and / or STA may configure / determine the NPCA interval. For example, the start time of NPCA may be based on the BasicNAV configuration and / or maintenance method. For example, the NPCA start time may be set to immediately upon receiving the ICF / ICR of the OBSS, or upon receiving (acquiring) the preamble of the first OBSS PPDU after the ICF / ICR exchange. As another example, the NPCA start time may be set to the time when the preamble of the OBSS PPDU is received (acquired) before the NAVTimeout period expires after receiving the ICF of the OBSS (without receiving the ICR). As another example, the NPCA start time may be set to the time when the ICR is received (without receiving the ICF).

[0230] According to one embodiment of the present disclosure, the start time of NPCA (the operating period of NPCA) may be the same or different between the AP and the STA. Since data cannot be exchanged wirelessly between the AP and the STA (before NPCA) when an OBSS PPDU and / or an OBSS TXOP is detected (on the primary channel), the AP and the STA operate independently, and thus the start time of NPCA (the operating period of NPCA) may vary between the AP and the STA. For example, the start time of NPCA (the operating period of NPCA) may vary between the AP and the STA depending on the observation environment (e.g., hidden interference).

[0231] According to one embodiment of the present disclosure, during an NPCA period, an NPCA AP and / or an NPCA STA may operate multiple TXOPs on the NPCH. During NPCA operation, one or more TXOPs on the NPCH may be operated by the NPCA AP and / or the NPCA STA.

[0232] According to one embodiment of the present disclosure, a trigger-based operation may be applied during NPCA operation. An NPCA AP may identify one or more NPCA STAs performing NPCA and transmit data. An NPCA STA may not perform uplink transmission immediately due to contention on an anchor channel, and may obtain a TXOP or perform uplink transmission in a TB (trigger-based) PPDU format after receiving a trigger frame from the NPCA AP.

[0233] According to one embodiment of the present disclosure, a method of operating a TXOP in an NPCH while performing NPCA may be provided. One or more TXOPs may be operated in the NPCH during the NPCA period. In the description of one embodiment of the present disclosure, a TXOP operated in the NPCH may be named as an NPC (non-primary channel) TXOP, but the present disclosure is not limited to this name. Even if it is referred to as a TXOP in the description of one embodiment of the present disclosure, if it is operated in the NPCH, it may be understood as an NPC TXOP. That is, in the description of one embodiment of the present disclosure, TXOP and NPC TXOP may be used interchangeably.

[0234] According to one embodiment of the present disclosure, a condition for an NPC TXOP may be provided. An NPCA AP may start an NPC TXOP if a minimum operation time (NPC TXOP minimum time) of one or more NPC TXOPs is guaranteed. The NPC TXOP minimum time may include a transmission time of a control frame and / or a trigger frame and a transmission time of a response thereto and a UL / DU PPDU and an ACK (acknowledgement) / block ACK. When NPC TXOPs are continuously in operation, if the minimum time of the next NPC TXOP is longer than (or greater than) the remaining NPCA execution time (remaining NPCA interval), the NPCA may be terminated. When multiple NPC TXOPs are in operation, the NPCA may be terminated if the minimum time of the next NPC TXOP is longer than (or greater than) the remaining NPCA execution time (remaining NPCA interval). Conversely, if the minimum time of the next NPC TXOP is shorter than (or less than) the remaining NPCA execution time (remaining NPCA interval), the NPCA can continue to be performed. The NPCA AP can obtain a TXOP (NPC TXOP) through an EDCA procedure on the anchor channel within the NPCH.

[0235] According to one embodiment of the present disclosure, a procedure for acquiring an NPC TXOP may be provided. The procedure for acquiring an NPC TXOP may vary depending on whether an NPCA is initiated by an OBSS PPDU or an NPCA is initiated by an OBSS TXOP. This may be because an OBSS PPDU performs transmission corresponding to an OBSS within a corresponding time interval, but an OBSS TXOP may not perform transmission corresponding to an OBSS within all corresponding time intervals, and an OBSS TXOP may be terminated after transmission corresponding to an OBSS is performed in some time intervals, which may cause a synchronization problem. As an example of a synchronization issue, if, for example, an OBSS TXOP ends earlier than it was initially announced, the NPCA AP and NPCA STAs that are transmitting and receiving on the NPCH may not be able to recognize the early termination of the OBSS TXOP and thus may not be able to participate in contention on the primary channel. In this case, if an STA that is associated with the NPCA AP and has not performed NPCA attempts an uplink transmission, the NPCA AP will not be able to receive it. Furthermore, if the OBSS acquires a TXOP on the primary channel again, the NPCA AP and NPCA STAs may not be able to recognize the new transmission and thus may not be able to accurately determine when the OBSS transmission ends, making it difficult to determine whether to perform / continue NPCA.

[0236] When NPCA is initiated by OBSS PPDU, NPCA AP can acquire NPC TXOP for the maximum NPCA operation period (NPCA interval). That is, NPC TXOP interval can be acquired less than or equal to NPCA interval.

[0237] If the NPCA is initiated by an OBSS TXOP (e.g., an ICF-ICR exchange of the OBSS), an NPC TXOP may be acquired if it is determined that a TXOP longer than the NPC TXOP Minimum Time is available based on the preamble of the OBSS PPDU within the OBSS TXOP. If it is determined that a TXOP longer than the NPC TXOP Minimum Time is not available based on the preamble of the OBSS PPDU within the OBSS TXOP, an NPC TXOP may not be acquired.

[0238] According to one embodiment of the present disclosure, if the minimum time of the NPC TXOP is not secured, the NPCA AP may stop attempting to acquire the NPC TXOP and wait for reception of the OBSS PPDU on the primary channel. For example, if the minimum time of the NPC TXOP is not secured due to contention latency and / or OBSS reception on the NPCH, the NPCA AP may stop attempting to acquire the NPC TXOP and wait for reception of the OBSS PPDU on the primary channel.

[0239] According to one embodiment of the present disclosure, when an NPCA AP and / or an NPCA STA cannot acquire an NPC TXOP due to a short duration of an OBSS PPDU received on a primary channel when an NPC TXOP has not started, the NPCA AP and / or the NPCA STA may receive an OBSS PPDU. If an update of BasicNAV occurs after the reception of the OBSS PPDU, the update of BasicNAV may be reflected in the NPCA execution time. If the OBSS TXOP is terminated early, the NPCA AP may notify the NPCA STA of the termination of the NPCA. For example, if it is identified that the OBSS TXOP is terminated early due to reception of a CF-End, etc., the NPCA AP may (explicitly) notify the NPCA STA of the termination of the NPCA.

[0240] According to one embodiment of the present disclosure, one or more NPC TXOPs may occur during NPCA execution. The NPC TXOP may be trigger-based, and the NPCA AP may perform MU (multi-user) UL / DL scheduling for multiple STAs for which NPCA operation has been confirmed within the NPC TXOP. That is, the NPCA AP may perform MU UL / DL scheduling for STAs for which NPCA operation has been confirmed, and may not perform MU UL / DL scheduling for STAs for which NPCA operation has not been confirmed.

[0241] According to one embodiment of the present disclosure, a procedure for obtaining an NPC TXOP during NPCA, a method for using multiple NPC TXOPs (e.g., consecutive use), and a method for terminating NPCA may be provided.

[0242] Hereinafter, various embodiments of the present disclosure described above will be described in more detail. In the description of one embodiment of the present disclosure below, if an NPCA AP or an NPCA STA operates an anchor channel NAV timer and the anchor channel NAV timer has a value other than 0, NPCA may not be initiated. That is, if an NPCA AP or an NPCA STA operates an anchor channel NAV timer and the anchor channel NAV timer is 0, NPCA may be initiated.

[0243] A method for determining whether NPCA operates according to one embodiment of the present disclosure and a method for setting / determining an NPCA duration are described. In the description of one embodiment of the present disclosure, tNPCADuration may be the total time for an NPCA AP and / or an NPCA STA to perform NPCA. That is, tNPCADuration may be an NPCA duration. tNPCADuration is a duration of NPCA rather than a TXOP time, and each AP and / or STA participating in NPCA may obtain its value at the start of an OBSS TXOP.

[0244] FIG. 9 is a diagram illustrating an example of a method for setting an NPCA section according to one embodiment of the present disclosure.

[0245] FIG. 9 illustrates an example in which an 80 MHz bandwidth (P80) including (or consisting of) a primary channel and an 80 MHz bandwidth (S80, NPCH) including (or consisting of) a secondary channel are configured in a 160 MHz bandwidth. This is an example and the present disclosure is not limited thereto.

[0246] According to one embodiment of the present disclosure, tNPCADuration may be set after reception of an OBSS ICR (e.g., CTS) or after reception of a preamble of an OBSS PPDU. FIG. 9 illustrates a case where NCPA is initiated after reception of a CTS of an OBSS.

[0247] According to one embodiment of the present disclosure, tNPCADuration may be less than or equal to BasicNAV (of the primary channel) set by OBSS TXOP. When tNPCADuration expires, NPCA is terminated, and a tail delay time (T_d) due to returning to the primary channel may be considered. For example, an RTS may be detected in an 80MHz bandwidth (P80) to set BasicNAV, and an OBSS PPDU may be detected after a CTS. After detection of the OBSS PPDU, a BA (blockACK) corresponding to the OBSS PPDU may be detected. tNPCADuration may be initiated by reception of a CTS, and may be terminated before the tail delay time from the time of BasicNAV expiration. During tNPCADuration, an NPCA operation may be performed in an 80MHz bandwidth (S80).

[0248] A procedure for setting an NPCA section according to one embodiment of the present disclosure may be as follows.

[0249] (1) If the preamble of OBSS PPDU is received first (if NPCA is triggered by OBSS PPDU)

[0250] According to one embodiment of the present disclosure, each NPCA AP and / or NPCA STA that first receives the preamble of an OBSS PPDU can obtain the duration (T_p) of the OBSS PPDU. If T_p is shorter than a threshold (T_const), each NPCA AP and / or NPCA STA can regard the OBSS PPDU as a control frame and can receive the control frame. Otherwise (i.e., if T_p is greater than or equal to T_const), each NPCA AP and / or NPCA STA can stop receiving the OBSS PPDU and perform NPCA. Receiving the preamble of the OBSS PPDU first means that the NPCA is triggered by the OBSS PPDU, and tNPCADuration can be secured as the transmission time of the OBSS PPDU obtained from the preamble of the OBSS PPDU.

[0251] According to one embodiment of the present disclosure, T_const may be set to be greater than the sum of a plurality of transmission times. For example, T_const may be greater than the sum of the transmission times of a control frame and / or a trigger frame, a response thereto, and a data frame and ACK / blockACK. An OBSS PPDU may carry a control frame or a data frame, and a control frame may be shorter than a data frame. Unlike a data frame, a control frame requires reception, and therefore, when T_p is shorter than T_const as described above, the OBSS PPDU may be regarded as a control frame and reception may be performed, and otherwise (regarded as a data frame) NPCA may be performed.

[0252] (2) When OBSS TXOP is detected (when NPCA is triggered by OBSS ICF-ICR)

[0253] According to one embodiment of the present disclosure, in this case, the method of setting the NPCA interval (starting the NPCA interval) may vary depending on whether both the ICF and the ICR are detected, the ICF is detected (the ICR is not detected), or the ICR is detected (the ICF is not detected).

[0254] According to one embodiment of the present disclosure, each NPCA AP and / or NPCA STA that detects an OBSS TXOP:

[0255] 1) (If both ICF and ICR are detected) If OBSS PPDU reception occurs after ICF-ICR exchange, tNPCADuration can be started.

[0256] 2) (If ICF is detected) If the preamble of OBSS PPDU is received before the end of NAVtimeout period after ICF reception, tNPCADuration can be started.

[0257] 3) (If ICR is detected) tNPCADuration can be started immediately upon receiving an ICR. That is, each NPCA AP and / or NPCA STA can start tNPCADuration immediately upon receiving an ICR, even if it does not receive an ICF.

[0258] According to one embodiment of the present disclosure, tNPCADuration may be set to be the same or different from the NPCA AP and / or the NPCA STA. That is, tNPCADuration set by the NPCA AP and tNPCADuration set by the NPCA STA may be different. However, the end time of tNPCADuration may be the same for tNPCADuration set by the NPCA AP and tNPCADuration set by the NPCA STA. As described above, the start time of tNPCADuration may be different depending on whether ICF and / or ICR are received, and accordingly, the start points of tNPCADuration set by the NPCA AP and tNPCADuration set by the NPCA STA may be different, but the end time may be the same.

[0259] According to one embodiment of the present disclosure, an NPCA AP can initiate one or more TXOPs (i.e., NPC TXOPs) within tNPCADuration. When NPCA is initiated, the NPCA AP can identify an NPCA STA operating on a secondary channel. The NPCA AP can identify an NPCA STA operating on a secondary channel among NPCA STAs (e.g., all NPCA STAs associated with (or attached to) the NPCA AP). The NPCA AP can identify an NPCA STA by transmitting a trigger frame and receiving uplink transmission feedback therefor. For example, an NPCA STA operating on a secondary channel can be identified based on a buffer status report poll (BSRP), a multi user-request to send (MU-RTS), or a basic trigger frame. The BSRP can be information about the size of a buffer that the STA has. MU-RTS may trigger a CTS response. The basic trigger frame triggers uplink transmission of STAs and may include information on resources (i.e., resource units (RUs)) for transmission of TB PPDUs. The resource allocation method by the basic trigger frame may include allocation of RA-RU (random access-RU) using uplink OFDMA (orthogonal frequency division multiplex access)-based random access (UORA). In this case, the NPCA STA can perform uplink transmission through contention (immediately after receiving the basic trigger frame). The NPCA AP can identify the NPCA STA performing the NPCA operation based on this.And / or the NPCA STA may transmit a PS (power saving)-Poll frame and / or a QoS Null Data and / or other frame after receiving a basic trigger frame to inform the NPCA STA that the NPCA STA is performing NPCA operation.

[0260] According to one embodiment of the present disclosure, an NPCA AP can perform UL / DL scheduling for an NPCA STA operating on an identified secondary channel.

[0261] According to one embodiment of the present disclosure, a TXOP within tNPCADuration may be configured for trigger-based operation. In order to protect (hidden) transmissions existing around an NPCA STA overlapping a secondary channel, the NPCA AP may request an ICR requiring CS (carrier sense) from the NPCA STA in response to an ICF sent by the NPCA AP. The NPCA AP and the NPCA STA may want to operate on an NPCH including an anchor channel for performing NPCA. In this case, in order to protect transmissions within the existing NPCH, the NPCA AP may solicit a response such as an ICR (e.g., CTS) while opening an NPC TXOP. To this end, a CS required may be set in a frame sent by the NPCA AP, and the NPCA STA receiving the frame may determine whether the NPCH is idle / busy after the trigger frame, and transmit a response (ICR (e.g., CTS)) only when it is idle. When an NPCA AP receives a response ICR (e.g., CTS) from an NPCA STA, it recognizes that the NPCA STA is operating normally and can then schedule data frame exchanges, etc.

[0262] FIG. 10 is a drawing for explaining an example of an NPCA operation notification message format according to one embodiment of the present disclosure.

[0263] FIG. 11 is a drawing for explaining an example of an NPCA operation notification message format according to one embodiment of the present disclosure.

[0264] FIG. 12 is a diagram illustrating an example of an NPCA operation notification message format according to one embodiment of the present disclosure.

[0265] FIG. 13 is a drawing for explaining an example of an NPCA operation notification message format according to one embodiment of the present disclosure.

[0266] According to one embodiment of the present disclosure, when initiating a TXOP using a trigger frame while NPCA is in operation, the NPCA AP may set a subfield (within the trigger frame) indicating that the TXOP belongs to NPCA. This subfield may be referred to as an NPCA notification subfield or an NPC TXOP notification subfield. The names are examples and the present disclosure is not limited thereto.

[0267] According to one embodiment of the present disclosure, TXOP within tNPCADuration can be set to trigger-based operation. That is, the NPCA STA can operate in a trigger-based manner. The NPCA AP can transmit information indicating that the NPCA AP is in NPCA operation to the NPCA STA by including it in a trigger frame for trigger-based operation.

[0268] A trigger frame format is exemplified in FIG. 10. The trigger frame may include a Frame Control field (2 octets), a Duration field (2 octets), a receiver address (RA) field (6 octets), a transmitter address (TA) field (6 octets), a Common Info field (8 octets or more), a User Info List field (variable), a Padding field (variable), and a frame check sum (FCS) field (4 octets). The User Info List field may include one or more User Info fields. According to one embodiment of the present disclosure, an NPCA notification subfield or an NPC TXOP notification subfield may be set within the Reserved subfield of the Common Info field or the User Info field (Special User Info field).

[0269] In Fig. 11, the EHT (extremely high throughput) variant Common Info field format (EHT variant common information field format) is exemplified.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, B023 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 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 that the NPCA AP is in NPCA operation. That is, B22, B26, B53, or B63 within the EHT variant Common Info field may be used as a 1-bit notification.

[0270] In Fig. 12, the Special User Info field format is exemplified. The Special User Info field may include an AID12 subfield (12 bits, B0 to B11), a PHY (physical) Version Identifier subfield (3 bits, B12 to B14), a UL Bandwidth Extension subfield (2 bits, B15 to B16), an EHT Spatial Reuse 1 subfield (4 bits, B17 to B20), an EHT Spatial Reuse 2 subfield (4 bits, B21 to B24), a U-SIG (Universal SIGNAL) Disregard And Validate subfield (12 bits, B25 to B36), a Reserved subfield (3 bits, B37 to B39), and a Trigger Dependent Common Info subfield (variable). According to one embodiment of the present disclosure, the Reserved subfield within the Special User Info field may be used to convey information indicating that the NPCA AP is in NPCA operation. That is, one bit from B37 to B39 within the Special User Info field may be used as a one-bit notification.

[0271] In Fig. 13, the EHT variant User Info field format (EHT variant user information field format) is exemplified. 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 that the NPCA AP is in NPCA operation. That is, B25 within the EHT variant User Info field may be used as a 1-bit notification.

[0272] An NPC TXOP within an NPCA interval (an interval of NPCA operation) according to one embodiment of the present disclosure is described. Here, the NPCA interval may be determined by at least some of the methods according to one embodiment of the present disclosure described above, but the present disclosure is not limited thereto.

[0273] In the description of one embodiment of the present disclosure, T_NPCA can be replaced with the tNPCADuration described above. That is, T_NPCA can be an NPCA interval. Conversely, the tNPCADuration described above can be replaced with T_NPCA.

[0274] Since NPC TXOP operates on a trigger-based basis, it may be necessary to secure the ICF-ICR exchange time required to identify an STA in NPCA operation, as well as the basic time required for the subsequent multi-user (MU) data exchange within the TXOP. Accordingly, the minimum TXOP interval length for NPCA needs to be defined / set.

[0275] According to one embodiment of the present disclosure, a minimum length of a TXOP interval for NPCA (minNPCATXOPDuration) may be defined. minNPCATXOPDuration may mean a minimum time length of a TXOP that an NPCA AP may set for NPCA operation within T_NPCA.

[0276] According to one embodiment of the present disclosure, minNPCATXOPDuration can be set / defined based on transmission times of multiple PPDUs. minNPCATXOPDuration can be set / defined considering transmission times of multiple (or several) PPDU exchanges. Here, the transmission time of a PPDU or PPDU exchange can include transmission times of one or more control frames (e.g., CF_End, CTS, etc.) and transmission times of one or more responses thereto, and the sum transmission time of DL MU PPDU and / or TB (trigger-based) PPDU and immediate response thereto (e.g., ACK, BlockAck). minNPCATXOPDuration can be defined to be greater than the minimum time required for actual transmission and reception. For example, the minimum time can be defined as the time required for transmitting a control frame and responding to it, followed by one data transmission and reception and response to it, and minNPCATXOPDuration can be defined to be greater than this. Since data transmission and reception can be performed multiple times within a TXOP, minNPCATXOPDuration can be defined to be greater than the minimum reference time described above. That is, minNPCATXOPDuration can be sufficiently longer than the transmission time of multiple PPDU exchanges including the transmission times of one or more control frames, the transmission times of one or more responses thereto, and the sum of the transmission times of DL MU PPDU and / or TB PPDU and their immediate responses. In addition, minNPCATXOPDuration can also be set / defined by taking into account the expected time required for EDCA contention in NPCH.

[0277] According to one embodiment of the present disclosure, one or more NPC TXOPs may exist in a T_NPCA, i.e., one or more NPC TXOPs may be configured in a T_NPCA. The NPC TXOP may be managed trigger-based. That is, an NPC STA may not perform EDCA contention in a secondary channel during an NPC TXOP. An NPCA AP may schedule multiple MU DL transmissions for an NPCA STA for which secondary channel operation is confirmed (i.e., NPCA operation is confirmed) and / or receive UL TB PPDUs from an NPCA STA for which secondary channel operation is confirmed (i.e., NPCA operation is confirmed).

[0278] According to one embodiment of the present disclosure, an NPC TXOP initiation condition may be provided. One or more of the conditions according to the following embodiments may be applied as the NPC TXOP initiation condition.

[0279] According to one embodiment of the present disclosure, an NPC TXOP may be initiated by an NPCA AP after the NPCA AP participates in an EDCA contention within a pre-allocated anchor channel during T_NPCA.

[0280] According to one embodiment of the present disclosure, the AP may initiate an NPC TXOP if minNPCATXOPDuration, i.e., the minimum duration of the NPC TXOP, is guaranteed. That is, if the minimum duration of the NPC TXOP is not guaranteed, the NPC TXOP may not be initiated.

[0281] According to one embodiment of the present disclosure, if an NPCA AP has a separate NAV timer (NPCANAVTimer) within the anchor channel, the NPCA AP may not initiate an NPC TXOP if the NPCANAVTimer has a non-zero value. Conversely, if an NPCA AP has a separate NAV timer (NPCANAVTimer) within the anchor channel, the NPCA AP may initiate an NPC TXOP if the NPCANAVTimer has a value of zero.

[0282] According to one embodiment of the present disclosure, if the remaining T_NPCA is less than minNPCATXOPDuration, i.e., no additional NPC TXOP can be initiated, the NPCA AP and / or NPCA STA may terminate NPCA and return to the primary channel.

[0283] According to one embodiment of the present disclosure, a maximum wait time (tNPCAWaitPPDULimit) for receiving a preamble of an OBSS PPDU on a primary channel may be defined / set. An NPCA AP may receive the preamble of an OBSS PPDU to obtain the period of the next NPC TXOP.

[0284] According to one embodiment of the present disclosure, when tNPCAWaitPPDULimit expires, the NPCA AP may initiate an NPC TXOP. If the preamble of an OBSS PPDU is not received on the primary channel and tNPCAWaitPPDULimit expires, the NPCA AP may initiate an NPC TXOP. It may be allowed to set the NPC TXOP period for the remaining time of T_NPCA.

[0285] According to one embodiment of the present disclosure, if the NPCA AP receives an OBSS PPDU (its preamble) on the primary channel before tNPCAWaitPPDULimit expires, the NPCA AP can secure an NPC TXOP until the transmission time of the OBSS PPDU.

[0286] According to one embodiment of the present disclosure, tNPCAWaitPPDULimit can be set to SIFS + N * slot duration. For example, N can be 1 or 2. For example, N = 1 can be the default value, and N = 2 can be applied after reception of an OBSS trigger frame. That is, tNPCAWaitPPDULimit can be applied to PIFS (i.e., SIFS + slot duration) by default, and can be applied to DIFS (i.e., SIFS + 2 * slot duration) after reception of an OBSS trigger frame.

[0287] According to one embodiment of the present disclosure, if NPCA is triggered by an OBSS PPDU (a long OBSS PPDU, e.g., an OBSS PPDU longer than minNPCATXOPDuration), an NPCA AP may be allowed to set an NPC TXOP equal to T_NPCA. If NPCA is triggered by an OBSS TXOP (e.g., receiving a control frame exchange on the primary channel), the NPCA AP may have to wait for reception of a preamble of an OBSS PPDU on the primary channel until the end of tNPCAWaitPPDULimit to acquire an OBSS PPDU duration.

[0288] More specific details of the NPC TXOP section setting corresponding to the OBSS TXOP of the primary channel according to one embodiment of the present disclosure are as follows.

[0289] (1) According to one embodiment of the present disclosure, an NPCA AP may wait for an OBSS PPDU within a primary channel.

[0290] - According to one embodiment of the present disclosure, if no preamble is detected from an OBSS PPDU within the primary channel during tNPCAWaitPPDULimit, the NPCA AP may be allowed to set an NPC TXOP interval equal to the remaining time of T_NPCA.

[0291] - According to one embodiment of the present disclosure, when one TXOP is terminated, the NPCA AP can run tNPCAWaitPPDULimit again.

[0292] (2) According to one embodiment of the present disclosure, after receiving an OBSS PPDU, the NPCA AP can initiate an NPC TXOP.

[0293] - According to one embodiment of the present disclosure, if an OBSS PPDU received on a primary channel is longer than minNPCATXOPDuration, an NPCA AP may be allowed to initiate a TXOP after EDCA contention on a secondary channel, and the end time of the NPC TXOP may be set to be the same as the end time of the OBSS PPDU.

[0294] - According to one embodiment of the present disclosure, if an OBSS PPDU received on the primary channel is shorter than minNPCATXOPDuration, the NPCA AP and / or NPCA STA may attempt to successfully receive (decode) the OBSS PPDU.

[0295] - If the OBSS PPDU is a control frame (e.g., CF-End or CTS) and thus the OBSS TXOP interval is updated, the NPCA AP and / or NPCA STA can update the NAV (Basic NAV) of the primary channel and T_NPCA. If the OBSS PPDU is CF-End, since the OBSS TXOP interval is 0, T_NPCA can also be 0. This may be because it may be considered advantageous to perform transmission and reception on the primary channel by participating in EDCA contention again after receiving the control frame rather than performing transmission and reception through NPCA on the secondary channel when the OBSS PPDU is a control frame.

[0296] (3) According to one embodiment of the present disclosure, after the termination of NPC TXOP, the following post-processing may be performed.

[0297] - After the NPC TXOP ends, if the remaining time of T_NPCA is less than or equal to minNPCATXOPDuration, i.e., no additional NPC TXOP can be initiated, the NPCA AP and / or NPCA STA may terminate the NPCA and return to the primary channel. In this case, the NPCA AP may (explicitly) notify the NPCA STA of the termination of the NPCA.

[0298] - Otherwise, the NPCA AP and / or NPCA STA may wait for reception of the preamble of the next OBSS PPDU on the primary channel for tNPCAWaitPPDULimit. That is, after the NPC TXOP ends, if the remaining time of T_NPCA is greater than minNPCATXOPDuration, i.e., if an additional NPC TXOP can be started, the NPCA AP and / or NPCA STA may wait for reception of the preamble of the next OBSS PPDU on the primary channel for tNPCAWaitPPDULimit.

[0299] Among the NPCA AP and / or NPCA STA, at least the NPCA AP may need to confirm or attempt to confirm the primary channel in order to perform transmission by participating in EDCA contention on a secondary channel (anchor channel) for the NPCA operation after initiating the NPCA operation. That is, the NPCA AP may need to attempt to detect a PPDU (OBSS PPDU) of the primary channel before performing transmission by participating in EDCA contention on a secondary channel (anchor channel) for the NPCA operation. In consideration of this, in one embodiment of the present disclosure, tNPCAWaitPPDULimit may be proposed as described above, which is the maximum time interval during which confirmation of the primary channel or detection of a PPDU of the primary channel must be attempted.

[0300] FIG. 14 is a diagram illustrating an example of the operation of an NPCA AP related to an NPC TXOP according to one embodiment of the present disclosure.

[0301] FIG. 14 illustrates an example in which an 80 MHz bandwidth (P80) including (or consisting of) a primary channel and an 80 MHz bandwidth (S80, NPCH) including (or consisting of) a secondary channel are configured in a 160 MHz bandwidth. This is an example and the present disclosure is not limited thereto.

[0302] Referring to FIG. 14, for example, when NPCA is triggered by ICF-ICR exchange, the NPCA AP may wait for reception of a preamble of an OBSS PPDU during tNPCAWaitPPDULimit. If the preamble of the OBSS PPDU is received within tNPCAWaitPPDULimit, information about the section of the OBSS PPDU may be identified based on the preamble. If the OBSS PPDU is longer than minNPCATXOPDuration, the NPCA AP may initiate NPC TXOP#1 after EDCA contention on the secondary channel. Here, the end time of NPC TXOP#1 may be set to be the same as the end time of the OBSS PPDU. Transmission (e.g., transmission for TF, R (response), NPCA MU PPDU, BA) may be performed within NPC TXOP#1. Multiple data can be exchanged between NPCA AP and NPCA STA within NPC TXOP#1.

[0303] For example, when NPC TXOP#1 is terminated and NPC TXOP#2 can be started, the NPCA AP and / or NPCA STA may wait for reception of the preamble of the next OBSS PPDU on the primary channel for tNPCAWaitPPDULimit (after the BA corresponding to the first OBSS PPDU). If the preamble of the OBSS PPDU is received within tNPCAWaitPPDULimit, information about the duration of the OBSS PPDU can be identified based on the preamble. If the OBSS PPDU is longer than minNPCATXOPDuration, the NPCA AP may initiate NPC TXOP#2 after EDCA contention on the secondary channel. Herein, the end time of NPC TXOP#2 can be set to be the same as the end time of the OBSS PPDU. Transmissions (e.g., transmissions for TF, NPCA TB PPDU, BA) can be performed within NPC TXOP#2. Multiple data can be exchanged between NPCA AP and NPCA STA within NPC TXOP#2.

[0304] For example, when NPC TXOP#2 is terminated and NPC TXOP#N can start, the NPCA AP and / or NPCA STA may wait for reception of the preamble of the next OBSS PPDU on the primary channel for tNPCAWaitPPDULimit (after the BA corresponding to the second OBSS PPDU). If the preamble of the OBSS PPDU is received within tNPCAWaitPPDULimit, information about the duration of the OBSS PPDU can be identified based on the preamble. If the OBSS PPDU is shorter than minNPCATXOPDuration, the NPCA AP may attempt to successfully receive (decode) the OBSS PPDU. If the OBSS PPDU is a control frame (e.g., CF-End or CTS) and thus the OBSS TXOP interval is updated, the NPCA AP can update the NAV (Basic NAV) of the primary channel and T_NPCA. If the OBSS PPDU is CF-End, since the OBSS TXOP interval is 0, T_NPCA can also be 0. That is, the NPCA operation is terminated and the NPCA AP can perform transmission (e.g., transmission of a DL MU PPDU) after performing EDCA contention on the primary channel.

[0305] According to one embodiment of the present disclosure, a procedure may be provided for a case where an NPC TXOP cannot (actually) be obtained due to an anchor channel issue.

[0306] According to one embodiment of the present disclosure, a problem in the anchor channel may be that EDCA contention is not completed (on the anchor channel). For example, EDCA contention may not be completed if 1) an OBSS PPDU preamble overlapping with the anchor channel is received, and / or 2) another OBSS PPDU is detected in the NPCH, and / or 3) a randomly selected backoff value (backoff number) in the EDCA contention is too high. A backoff value that is too high may mean that the actually available NPC TXOP period is shortened due to waiting for an idle slot corresponding to the backoff value, so that minNPCATXOPDuration cannot be secured.

[0307] If EDCA contention is not completed due to a problem with the anchor channel, i.e., in at least one of the above cases 1) to 3), it may be difficult to secure NPC TXOP equal to minNPCATXOPDuration. Therefore, according to one embodiment of the present disclosure, if the OBSS PPDU or OBSS TXOP received within the NPCH is greater than the difference between the remaining time of T_NPCA and minNPCATXOPDuration (remaining time of T_NPCA - minNPCATXOPDuration), the NPCA AP may immediately terminate NPCA.

[0308] According to one embodiment of the present disclosure, an STA waiting for reception of a trigger frame from an NPCA AP on the NPCH may also terminate NPCA depending on a problem with the anchor channel. For example, an STA waiting for reception of a trigger frame from an NPCA AP on the NPCH may terminate NPCA if 1) an OBSS PPDU preamble overlapping with the anchor channel is received, and / or 2) another OBSS PPDU is detected on the NPCH.

[0309] According to one embodiment of the present disclosure, when an NPCA AP or NPCA STA drives NPCNAVTimer, the NPCA AP or NPCA STA can update the value of NPCNAVTimer to correspond to an OBSS TXOP.

[0310] FIG. 15 is a diagram illustrating an example of the operation of an NPCA AP / NPCA STA related to an NPC TXOP according to an embodiment of the present disclosure. FIG. 15 illustrates an example of the above-described anchor channel problem 2) when another OBSS PPDU is detected in the NPCH. The following description focuses on the NPCA AP, but as described above, the same can be applied to the NPCA STA as well.

[0311] FIG. 15 illustrates an example in which an 80 MHz bandwidth (P80) including (or consisting of) a primary channel and an 80 MHz bandwidth (S80, NPCH) including (or consisting of) a secondary channel are configured in a 160 MHz bandwidth. This is an example and the present disclosure is not limited thereto.

[0312] Referring to FIG. 15, for example, when NPCA is triggered by ICF-ICR exchange in 80MHz bandwidth (P80), the NPCA AP STA may initiate NPCA. However, when another OBSS PPDU is detected in NPCH (80MHz bandwidth (S80)), if the OBSS PPDU is greater than the difference between the remaining time of T_NPCA and minNPCATXOPDuration (remaining time of T_NPCA - minNPCATXOPDuration), the NPCA AP may immediately terminate NPCA. In this case, after the transmission of OBSS (e.g., OBSS PPDU, BA) in 80MHz bandwidth (P80) is terminated, the transmission after EDCA (e.g., transmission of DL MU PPPU) may be performed.

[0313] FIG. 16 is a diagram illustrating an example of an NPCA procedure according to an embodiment of the present disclosure. FIG. 16 illustrates an example of a method by which an NPCA AP determines whether to operate NPCA according to an embodiment of the present disclosure and a method by which an NPCA period (duration) is set / determined.

[0314] The flowchart of FIG. 16 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 depicted in the flowchart. For example, although depicted 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.

[0315] Referring to FIG. 16, according to one embodiment of the present disclosure, after NPCA is prepared, the NPCA AP can detect an OBSS PPDU and obtain the section T_p of the OBSS PPDU from the received preamble (1601).

[0316] According to one embodiment of the present disclosure, the NPCA AP can compare T_p and T_const (1603). The NPCA AP can identify whether T_p is greater than T_const.

[0317] According to one embodiment of the present disclosure, if T_p is identified as being greater than T_const in 1603, the NPCA AP may drive (initiate) NPCA. The NPCA AP may set tNPCADuration to T_p-T_d (1605). That is, the NPCA AP may set the end time of tNPCADuration to be T_d earlier than the end time of the OBSS PPDU. The NPCA AP may wait until tNPCADuration expires (1607) and terminate NPCA.

[0318] According to one embodiment of the present disclosure, if T_p is identified as not greater than T_const in 1603, the NPCA AP can receive an OBSS frame (1609).

[0319] According to one embodiment of the present disclosure, the NPCA AP can identify whether an OBSS frame is an ICF (1611).

[0320] According to one embodiment of the present disclosure, if the OBSS frame is identified as an ICF at 1611, the NPCA AP may wait for an ICR or OBSS PPDU (1613).

[0321] According to one embodiment of the present disclosure, the NPCA AP can identify whether an ICR has been received after SIFS (from the ICF) (1615).

[0322] According to one embodiment of the present disclosure, if it is determined that no ICR is received at 1615, the NPCA AP may wait for an OBSS PPDU until the NAVTimeout period (1617, 1619). If no OBSS PPDU is detected at 1619, the NPCA AP may terminate NPCA. If an OBSS PPDU is detected at 1619, the NPCA AP may start (initiate) NPCA. The NPCA AP may set tNPCADuration to BasicNAV-T_d (1623). That is, the NPCA AP may set the end time of tNPCADuration to be T_d earlier than the end time of BasicNAV. The NPCA AP may wait until tNPCADuration expires (1607) and terminate NPCA.

[0323] According to one embodiment of the present disclosure, if it is identified that an ICR has been received at 1615, the NPCA AP may initiate NPCA. The NPCA AP may set tNPCADuration to BasicNAV-T_d (1623). The NPCA AP may wait until tNPCADuration expires (1607) and terminate NPCA.

[0324] According to one embodiment of the present disclosure, if the OBSS frame is identified as not being an ICF at 1611, the NPCA AP may identify whether the OBSS frame is an ICR (1621). If the OBSS frame is identified as not being an ICR at 1621, the NPCA AP may terminate NPCA. If the OBSS frame is identified as being an ICR at 1621, the NPCA AP may start (initiate) NPCA. The NPCA AP may set tNPCADuration to BasicNAV-T_d (1623). The NPCA AP may wait until tNPCADuration expires (1607) and terminate NPCA.

[0325] For more specific details on the operation of the NPCA 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.

[0326] FIG. 17 is a diagram illustrating an example of an NPC TXOP operation within an NPCA according to an embodiment of the present disclosure. FIG. 17 illustrates an example of a method by which an NPCA AP performs a procedure related to an NPC TXOP within an NPCA section according to an embodiment of the present disclosure.

[0327] The flowchart of FIG. 17 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 depicted in the flowchart. For example, although depicted 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.

[0328] Referring to FIG. 17, according to one embodiment of the present disclosure, after NPCA is started, the NPCA AP can determine whether NPCA is triggered by an OBSS TXOP (1701). Conversely, the NPCA AP can determine whether NPCA is triggered by an OBSS PPDU. BasicNAV can be set in the NPCA AP.

[0329] According to one embodiment of the present disclosure, if NPCA is identified as being triggered by an OBSS TXOP at 1701 (i.e., not triggered by an OBSS PPDU), the NPCA AP may wait for reception of an OBSS PPDU on the primary channel for tNPCAWaitPPDULimit (1703, 1705).

[0330] According to one embodiment of the present disclosure, if tNPCAWaitPPDULimit expires at 1703, 1705 and no OBSS PPDU preamble is received, the NPCA AP may initiate EDCA contention with the goal of securing NPC TXOP until the remaining T_NPCA (1707).

[0331] According to one embodiment of the present disclosure, the NPCA AP can identify whether an NPC TXOP has been initiated (1709).

[0332] According to one embodiment of the present disclosure, if the NPC TXOP is identified as not initiated at 1709, the NPCA AP may still determine whether minNPCATXOPDuration is available (1711). If it is identified as available at 1711, the NPCA AP may perform the operations described in 1707 and thereafter.

[0333] According to one embodiment of the present disclosure, if it is identified as unavailable at 1711, the NPCA AP may update the NPCNAVTimer if necessary and terminate NPCA (1713).

[0334] According to one embodiment of the present disclosure, if an NPC TXOP is identified as initiated at 1709, data may be transmitted until the end of the NPC TXOP (1715). Thereafter, the NPCA AP may notify other NPCA STAs of the end of the NPCA and return to the primary channel (1717), after which the NPCA may be terminated.

[0335] According to one embodiment of the present disclosure, if NPCA is identified as not being triggered by an OBSS TXOP at 1701 (i.e., identified as being triggered by an OBSS PPDU), the NPCA AP may initiate EDCA contention with the goal of securing an NPC TXOP until the remaining T_NPCA (1707). The NPCA AP may then perform the operations as per 1709 and thereafter.

[0336] According to one embodiment of the present disclosure, if an OBSS PPDU preamble is received before tNPCAWaitPPDULimit expires at 1703, 1705, the NPCA AP may compare the duration of the OBSS PPDU with minNPCATXOPDuration (1719). The NPCA AP may identify whether the duration of the OBSS PPDU is greater than minNPCATXOPDuration.

[0337] According to one embodiment of the present disclosure, if the duration of the OBSS PPDU is identified as not greater than minNPCATXOPDuration at 1719, the NPCA AP can receive the OBSS PPDU (1721).

[0338] According to one embodiment of the present disclosure, the NPCA AP may update BasicNAV and T_NPCA, if necessary (1723).

[0339] According to one embodiment of the present disclosure, the NPCA AP can still determine whether minNPCATXOPDuration is available (1725). If it is determined to be available at 1725, the NPCA AP can perform the operations described in 1703 and thereafter.

[0340] According to one embodiment of the present disclosure, if it is identified as unavailable at 1725, the NPCA AP may update the NPCNAVTimer if necessary and terminate NPCA (1727).

[0341] According to one embodiment of the present disclosure, if the duration of the OBSS PPDU is identified as being greater than minNPCATXOPDuration at 1719, the NPCA AP may initiate EDCA contention with the goal of securing an NPC TXOP from the preamble of the OBSS PPDU to the duration of the acquired OBSS PPDU (1729).

[0342] According to one embodiment of the present disclosure, the NPCA AP can identify whether an NPC TXOP has been initiated (1731).

[0343] According to one embodiment of the present disclosure, if the NPC TXOP is identified as not initiated at 1731, the NPCA AP may perform the actions according to 1725 and thereafter.

[0344] According to one embodiment of the present disclosure, if an NPC TXOP is identified as initiated at 1731, the NPCA AP may perform data transmission until the end of the NPC TXOP (1733). Thereafter, the NPCA AP may perform operations according to 1725 and thereafter.

[0345] For more specific details on the operation of the NPCA 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.

[0346] Below, examples of operations according to various embodiments of the present disclosure are described with reference to the drawings. The following description may be applied to the various embodiments of the present disclosure described above. The following examples are provided to facilitate understanding of the various embodiments of the present disclosure, and the present disclosure is not limited to the following examples.

[0347] Hereinafter, an 80MHz bandwidth (P80) including (or configured as) a primary channel and an 80MHz bandwidth (S80, NPCH) including (or configured as) a secondary channel are configured in a 160MHz bandwidth. This is an example and the present disclosure is not limited thereto. Hereinafter, an NPCA AP is capable of operating in a 160MHz bandwidth and an NPCA STA is capable of operating in 80MHz or 160MHz, but the present disclosure is not limited thereto.

[0348] FIG. 18 is a diagram illustrating an example of an operation related to an NPC TXOP within an NPCA operation period according to one embodiment of the present disclosure. FIG. 18 illustrates a basic NPCA operation when an ICF-ICR exchange is observed at 80 MHz bandwidth (P80).

[0349] Referring to Fig. 18, OBSS ICF, OBSS ICR, OBSS PPDU, and OBSS BA can be transmitted in 80 MHz bandwidth (P80). The NPCA AP initially attempts to connect to the primary channel, but can detect the OBSS ICF-ICR exchange. The NPCA AP can set BasicNAV and tNPCADuration. tNPCADuration can be set after receiving the OBSS ICR or after receiving the OBSS PPDU. NPCA, i.e., tNPCADuration, can be terminated earlier than BasicNAV considering the switching delay time due to returning to the primary channel.

[0350] The NPCA STA initially attempts to connect to the primary channel, but can detect an OBSS ICF-ICR exchange. The NPCA STA can set BasicNAV and tNPCADuration. tNPCADuration can be set after receiving an OBSS ICR or after receiving an OBSS PPDU. NPCA, i.e., tNPCADuration, can be terminated before BasicNAV to account for the switching delay time due to returning to the primary channel.

[0351] An NPCA AP can initiate EDCA contention on the anchor channel within the NPCH. The NPCA AP can receive the preamble of the OBSS PPDU and set the duration of the NPC TXOP (NPC TXOP#1) to the end of the OBSS PPDU. As described above, since the NPC TXOP is trigger-based, an NPCA STA may not perform EDCA contention on the anchor channel.

[0352] Within an NPC TXOP, multiple data can be exchanged between an NPCA AP and an NPCA STA. For example, TF, response, NPCA MU PPDU, BA, etc. can be exchanged. The TF can contain information indicating that the NPCA AP is performing NPCA (or has initiated NPCA, or is in NPCA operation). The NPC TXOP can end at (exactly) the same time as the OBSS PPDU.

[0353] After tNPCADuration ends, the NPCA AP returns to the primary channel and can participate in contention after BasicNAV ends, and can perform transmission (e.g., transmission of DL MU PPDU) based on the contention result.

[0354] FIG. 19 is a diagram illustrating an example of an operation related to an NPC TXOP within an NPCA operation period according to one embodiment of the present disclosure. FIG. 19 illustrates a case in which no OBSS PPDU is received and only an ICR is received (No OBSS PPDU reception, that is, only ICR is received) in an 80 MHz bandwidth (P80).

[0355] Referring to FIG. 19, OBSS ICF, OBSS ICR, OBSS PPDU, and OBSS BA can be transmitted in an 80 MHz bandwidth (P80).

[0356] The NPCA AP initially attempts to connect to the primary channel, but can detect the OBSS ICR. The NPCA AP cannot detect the OBSS ICF, and can only detect the OBSS ICR. The NPCA AP can set the BasicNAV of the primary channel and set tNPCADuration based on the point in time of the OBSS ICR.

[0357] In general, OBSS PPDU can be detected after OBSS ICR is received, but if OBSS ICF is not received / detected, OBSS PPDU may not be received due to hidden, etc. Taking this into account, NPCA AP can set NPC TXOP up to tNPCADuration if the primary channel is idle for PIFS time longer than the expected SIFS time at the time of OBSS PPDU reception.

[0358] NPCA, i.e. tNPCADuration, may be terminated earlier than BasicNAV to account for the switching delay associated with returning to the primary channel.

[0359] The NPCA STA initially attempts to connect to the primary channel, but can detect an OBSS ICF-ICR exchange. The NPCA STA can set BasicNAV and tNPCADuration. tNPCADuration can be set after receiving an OBSS ICR or after receiving an OBSS PPDU. NPCA, i.e., tNPCADuration, can be terminated before BasicNAV to account for the switching delay time due to returning to the primary channel.

[0360] An NPCA AP may not detect any OBSS PPDU within PIFS (tNPCAWaitPPDULimit) after receiving an OBSS ICR. The NPCA AP may initiate EDCA contention on the anchor channel within the NPCH. The NPCA AP may configure the duration of the NPC TXOP to be as long as possible. The NPCA AP may configure the end time of the NPC TXOP to be the end time of tNPCADuration. As described above, since the NPC TXOP is configured based on a trigger, the NPCA STA may not perform EDCA contention on the anchor channel.

[0361] Within an NPC TXOP, multiple data can be exchanged between an NPCA AP and an NPCA STA. For example, TF, response, NPCA MU PPDU, BA, etc. can be exchanged. The TF can include information indicating that the NPCA AP is performing NPCA (or has initiated NPCA, or is in NPCA operation).

[0362] After tNPCADuration ends, the NPCA AP returns to the primary channel and can participate in contention after BasicNAV ends, and can perform transmission (e.g., transmission of DL MU PPDU) based on the contention result.

[0363] FIG. 20 is a diagram illustrating an example of an operation related to an NPC TXOP within an NPCA operation period according to one embodiment of the present disclosure. FIG. 20 illustrates a case where an OBSS ICR is not received (No OBSS ICR reception) in an 80 MHz bandwidth (P80).

[0364] Referring to FIG. 20, OBSS ICF, OBSS ICR, OBSS PPDU, and OBSS BA can be transmitted in an 80 MHz bandwidth (P80).

[0365] The NPCA AP initially attempts to connect to the primary channel, but can detect an OBSS ICF. The NPCA AP can set BasicNAV and tNPCADuration. tNPCADuration can be set after receiving the preamble of the OBSS PPDU. NPCA, i.e. tNPCADuration, can be terminated before BasicNAV to take into account the switching delay time due to returning to the primary channel.

[0366] The NPCA STA initially attempts to connect to the primary channel, but can detect an OBSS ICF-ICR exchange. The NPCA STA can set BasicNAV and tNPCADuration. tNPCADuration can be set after receiving an OBSS ICR or after receiving an OBSS PPDU. NPCA, i.e., tNPCADuration, can be terminated before BasicNAV to account for the switching delay time due to returning to the primary channel.

[0367] An NPCA AP can receive the preamble of an OBSS PPDU before the NAVTimeout expires after receiving an OBSS ICF. The NPCA AP can detect the preamble of an OBSS PPDU but not the OBSS ICR after receiving an OBSS ICF. The NPCA AP can set tNPCADuration and initiate EDCA contention on the anchor channel in the NPCH to set the NPC TXOP. As described above, since the NPC TXOP is set based on a trigger, the NPCA STA may not perform EDCA contention on the anchor channel. Meanwhile, when the NAVTimeout (NAVTimer) expires after receiving an OBSS ICF (i.e., no OBSS PPDU is received until the NAVTimeout expires after receiving an OBSS ICF), the NPCA AP can reset BasicNAV and rejoin the contention on the primary channel.

[0368] Within an NPC TXOP, multiple data can be exchanged between an NPCA AP and an NPCA STA. For example, TF, response, NPCA MU PPDU, BA, etc. can be exchanged. The TF can contain information indicating that the NPCA AP is performing NPCA (or initiating NPCA, or in NPCA operation). An NPC TXOP can end (exactly) at the same time as an OBSS PPDU. In this case, the NPCA AP can wait to receive the preamble of the (next) OBSS PPDU.

[0369] After tNPCADuration ends, the NPCA AP returns to the primary channel and can participate in contention after BasicNAV ends, and can perform transmission (e.g., transmission of DL MU PPDU) based on the contention result.

[0370] FIG. 21 is a diagram illustrating an example of an operation related to an NPC TXOP within an NPCA operation period according to one embodiment of the present disclosure. FIG. 21 illustrates a case in which an OBSS ICF observed in an 80 MHz bandwidth (P80) is a trigger frame (OBSS TF) not an MU-RTS (Case that OBSS ICF is trigger frame not MU-RTS).

[0371] If the type of OBSS TF is not Basic TF (e.g., BSRP, BQRP (Bandwidth Query Report Poll), NFRP (NDP (null data PPDU) Feedback Report Poll), etc.), the length of TB PPDU may not be sufficient to set up NPC TXOP in general. Taking this into account, Basic TF is exemplified in FIG. 21.

[0372] Referring to FIG. 21, OBSS TF, OBSS HE TB PPDU, and OBSS M-BA (multi-user BA) can be transmitted in an 80 MHz bandwidth (P80).

[0373] The NPCA AP initially attempts to connect to the primary channel, but can detect the OBSS Basic TF. The NPCA AP can set BasicNAV and tNPCADuration. tNPCADuration can be set after receiving the preamble of the OBSS HE TB PPDU. NPCA, i.e. tNPCADuration, can be terminated before BasicNAV to take into account the switching delay time due to returning to the primary channel.

[0374] The NPCA STA initially attempts to connect to the primary channel, but can detect the OBSS Basic TF. The NPCA STA can set BasicNAV and tNPCADuration. tNPCADuration can be set after receiving the preamble of the OBSS HE TB PPDU. NPCA, i.e., tNPCADuration, can be terminated before BasicNAV to take into account the switching delay time due to returning to the primary channel.

[0375] An NPCA AP can set tNPCADuration and initiate EDCA contention on the anchor channel within the NPCH to establish an NPC TXOP. As described above, since the NPC TXOP is set based on a trigger, an NPCA STA may not perform EDCA contention on the anchor channel.

[0376] Within an NPC TXOP, multiple data can be exchanged between an NPCA AP and an NPCA STA. For example, TF, response, NPCA MU PPDU, BA, etc. can be exchanged. The TF can contain information indicating that the NPCA AP is performing NPCA (or initiating NPCA, or in NPCA operation). The NPC TXOP can end at (exactly) the same time as the OBSS HE TB PPDU.

[0377] After tNPCADuration ends, the NPCA AP returns to the primary channel and can participate in contention after BasicNAV ends, and can perform transmission (e.g., transmission of DL MU PPDU) based on the contention result.

[0378] FIG. 22 is a diagram illustrating an example of an operation related to an NPC TXOP within an NPCA operation period according to one embodiment of the present disclosure. FIG. 22 illustrates a case in which an OBSS ICF observed in an 80 MHz bandwidth (P80) is a trigger frame (OBSS TF) not an MU-RTS (Case that OBSS ICF is trigger frame not MU-RTS).

[0379] Referring to FIG. 22, OBSS TF (basic TF), OBSS HE TB PPDU, and OBSS M-BA (multi-user BA) can be transmitted in an 80 MHz bandwidth (P80).

[0380] The NPCA AP initially attempts to connect to the primary channel, but can detect the OBSS TF. The NPCA AP can set BasicNAV and tNPCADuration. tNPCADuration can be set after the expiration time of tNPCAWaitPPDULimit. Here, the expiration time of tNPCAWaitPPDULimit can be the same as the time after DIFS-idle from the reception of the OBSS TF. In the example of Fig. 22, since the OBSS PPDU is hidden to the NPCA AP, the reception time of the OBSS PPDU preamble may not be the start time of tNPCADuration, and the expiration time of tNPCAWaitPPDULimit can be the start time of tNPCADuration. NPCA, i.e. tNPCADuration, may be terminated earlier than BasicNAV to account for the switching delay associated with returning to the primary channel.

[0381] The NPCA STA initially attempts to connect to the primary channel, but can detect an OBSS TF. The NPCA STA can set BasicNAV and tNPCADuration. tNPCADuration can be set after receiving the preamble of the OBSS HE TB PPDU. NPCA, i.e., tNPCADuration, can be terminated before BasicNAV to take into account the switching delay time due to returning to the primary channel.

[0382] After receiving an OBSS TF, the NPCA AP may attempt to detect an OBSS PPDU within DIFS (tNPCAWaitPPDULimit). If no OBSS PPDU is detected within DIFS (tNPCAWaitPPDULimit) after receiving an OBSS TF, the NPCA AP may set tNPCADuration and initiate EDCA contention on the anchor channel in the NPCH to establish an NPC TXOP. As described above, since the NPC TXOP is set based on a trigger, the NPCA STA may not perform EDCA contention on the anchor channel.

[0383] Within an NPC TXOP, multiple data can be exchanged between an NPCA AP and an NPCA STA. For example, TF, response, NPCA MU PPDU, BA, etc. can be exchanged. The TF can include information indicating that the NPCA AP is performing NPCA (or initiating NPCA, or in NPCA operation). The NPCA AP can set the duration of the NPC TXOP to be as long as possible. The NPCA AP can set the end time of the NPC TXOP to be the end time of tNPCADuration.

[0384] After tNPCADuration ends, the NPCA AP returns to the primary channel and can participate in contention after BasicNAV ends, and can perform transmission (e.g., transmission of DL MU PPDU) based on the contention result.

[0385] FIG. 23 is a diagram illustrating an example of an operation related to an NPC TXOP within an NPCA operation period according to an embodiment of the present disclosure. FIG. 23 illustrates a case where an OBSS PPDU longer than minNPCATXOPDuration is detected in an 80 MHz bandwidth (P80) (Long OBSS PPDU than minNPCATXOPDuration).

[0386] Referring to Figure 23, OBSS PPDU and OBSS BA can be transmitted in 80 MHz bandwidth (P80).

[0387] An NPCA AP initially attempts to connect to the primary channel, but may detect an OBSS PPDU that is (sufficiently) longer than minNPCATXOPDuration. The NPCA AP may set tNPCADuration, which may be set after receiving the preamble of the OBSS PPDU. NPCA, i.e., tNPCADuration, may be terminated earlier than the OBSS PPDU to account for the switching delay time due to returning to the primary channel.

[0388] An NPCA STA initially attempts to connect to the primary channel, but may detect an OBSS PPDU that is (sufficiently) longer than minNPCATXOPDuration. The NPCA STA may set tNPCADuration. tNPCADuration may be set after receiving the preamble of the OBSS PPDU. NPCA, i.e. tNPCADuration, may be terminated earlier than BasicNAV to account for the switching delay time due to returning to the primary channel.

[0389] An NPCA AP can set tNPCADuration and initiate EDCA contention on the anchor channel within the NPCH to establish an NPC TXOP. As described above, since the NPC TXOP is set based on a trigger, an NPCA STA may not perform EDCA contention on the anchor channel.

[0390] Within the NPC TXOP, multiple data may be exchanged between the NPCA AP and the NPCA STA. For example, TF, response, NPCA MU PPDU, BA, TF, NPCA TB PPDU, BA, etc. may be exchanged. The first TF transmitted from the NPCA AP illustrated in FIG. 23 may include information indicating that the NPCA AP performs NPCA (or initiates NPCA, or is in NPCA operation). The second TF transmitted from the NPCA AP illustrated in FIG. 23 may include information related to triggering transmission of the NPCA TB PPDU. For example, resource allocation information for the NPCA TB PPDU may be included. Meanwhile, the second TF may also include information indicating that the NPCA AP performs NPCA (or initiates NPCA, or is in NPCA operation). That is, during NPCA operation, any TF / control frame transmitted on the NPCH may contain information indicating that the NPCA AP is performing NPCA (or initiating NPCA, or in NPCA operation).

[0391] The NPCA AP can set the duration of the NPC TXOP to be as long as possible. The NPCA AP can set the end time of the NPC TXOP to be the end time of tNPCADuration.

[0392] After tNPCADuration ends, the NPCA AP returns to the primary channel and can participate in contention after OBSS BA ends, and can perform transmission (e.g., transmission of DL MU PPDU) based on the contention result.

[0393] FIG. 24 is a diagram illustrating an example of an operation related to an NPC TXOP within an NPCA operation period according to one embodiment of the present disclosure. FIG. 24 illustrates a case where multiple OBSS PPDUs are transmitted within an OBSS TXOP (multiple OBSS PPDUs within an OBSS TXOP).

[0394] Referring to Fig. 24, in the 80 MHz bandwidth (P80), OBSS ICF, OBSS ICR, multiple OBSS PPDUs, and multiple OBSS BAs can be transmitted. The NPCA AP initially attempts to connect to the primary channel, but can detect the OBSS ICF-ICR exchange. The NPCA AP can set BasicNAV and tNPCADuration. tNPCADuration can be set after receiving the OBSS ICR or after receiving the OBSS PPDU. NPCA, i.e., tNPCADuration, can be terminated earlier than BasicNAV considering the switching delay time due to returning to the primary channel.

[0395] The NPCA STA initially attempts to connect to the primary channel, but can detect an OBSS ICF-ICR exchange. The NPCA STA can set BasicNAV and tNPCADuration. tNPCADuration can be set after receiving an OBSS ICR or after receiving an OBSS PPDU. NPCA, i.e., tNPCADuration, can be terminated before BasicNAV to account for the switching delay time due to returning to the primary channel.

[0396] An NPCA AP can initiate EDCA contention on the anchor channel within the NPCH. When the NPCA AP receives the preamble of the OBSS PPDU and the transmission time of the OBSS PPDU is longer than minNPCATXOPDuration, it can participate in EDCA contention on the anchor channel to set an NPC TXOP. In this case, the NPCA AP can set the duration of NPC TXOP#1 to the end of the OBSS PPDU. As described above, since NPC TXOP#1 is set based on a trigger, the NPCA STA may not perform EDCA contention on the anchor channel.

[0397] Within an NPC TXOP, multiple data can be exchanged between an NPCA AP and an NPCA STA. For example, TF, response, NPCA MU PPDU, BA, etc. can be exchanged. The TF can contain information indicating that the NPCA AP is performing NPCA (or has initiated NPCA, or is in NPCA operation). The NPC TXOP can end at (exactly) the same time as the OBSS PPDU.

[0398] If an NPCA AP receives a preamble of an OBSS PPDU within an OBSS TXOP, and the OBSS PPDU duration is longer than minNPCATXOPDuration, the NPCA AP can initiate an NPCA TXOP. In the case of BA, since it is shorter than minNPCATXOPDuration, it does not trigger an NPCA TXOP, and instead, the NPCA AP can receive BA.

[0399] For example, after the BA transmission for the first OBSS PPDU, if the NPCA AP receives the preamble of the OBSS PPDU within the OBSS TXOP (within tNPCAWaitPPDULimit), and the OBSS PPDU duration is longer than minNPCATXOPDuration, the NPCA AP can initiate NPCA TXOP#2. That is, the NPCA AP can drive EDCA contention on the anchor channel within the NPCH. The NPCA AP can set the duration of NPC TXOP#2 to the end of the OBSS PPDU by receiving the preamble of the OBSS PPDU. As described above, since NPC TXOP#2 is set based on trigger, the NPCA STA may not perform EDCA contention on the anchor channel.

[0400] Within an NPC TXOP, multiple data may be exchanged between an NPCA AP and an NPCA STA. For example, TF, NPCA TB PPDU, BA, etc. may be exchanged. The TF may contain information related to triggering the transmission of an NPCA TB PPDU. For example, it may contain resource allocation information for the NPCA TB PPDU. NPC TXOP#2 may end at (exactly) the same time as the second OBSS PPDU. Meanwhile, the TF may contain information indicating that the NPCA AP performs NPCA (or initiates NPCA, or is in NPCA operation). That is, during NPCA operation, any TF / control frame transmitted on the NPCH may contain information indicating that the NPCA AP performs NPCA (or initiates NPCA, or is in NPCA operation).

[0401] After tNPCADuration ends, the NPCA AP returns to the primary channel and can participate in contention after BasicNAV ends, and can perform transmission (e.g., transmission of DL MU PPDU) based on the contention result.

[0402] 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.

[0403] 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 embodiments described in the claims or specification of the present disclosure.

[0404] 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.

[0405] 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.

[0406] 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.

[0407] 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.

[0408] 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.

[0409] 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.

[0410] 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.

[0411] 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. A method performed by a device in a wireless LAN (local access network) system, A step of initiating a transmission opportunity (TXOP) for NPCA on an NPCA primary channel for non-primary channel access (NPCA) based on enhanced distributed channel access (EDCA); A step of setting up a trigger frame, wherein the trigger frame includes a Special User Info field and the B37 bit of the Special User Info field includes a 1-bit indication related to the NPCA; and A method comprising the step of transmitting the trigger frame based on the NPCA primary channel after initiating a TXOP for the NPCA.

2. In paragraph 1, A method wherein the above 1-bit instruction is set to indicate that the device performs an operation related to the NPCA.

3. In paragraph 1, A method comprising the step of setting an operating time interval for the NPCA based on the time required to switch from the NPCA primary channel to the primary channel for the BSS (basic service set) corresponding to the device.

4. In paragraph 3, After identifying a PPDU (physical layer protocol data unit) or TXOP related to a BSS other than the BSS corresponding to the device on the primary channel for the BSS corresponding to the device, an operation time interval for the NPCA is set, The time interval of the PPDU related to the above other BSS is greater than or equal to a preset threshold, A method wherein the above preset threshold is set to be greater than or equal to the sum of (i) the transmission time for the exchange between a specific control frame and a response and (ii) the transmission time for the exchange between specific data and one or more of an ACK (acknowledgement) or a block ACK.

5. In paragraph 4, If a TXOP related to the other BSS is identified, an operation time interval for the NPCA is set after detecting a preamble of a first PPDU received on the primary channel for the BSS corresponding to the device after a control frame exchange including an ICF corresponding to the PHY-RXEND.indication primitive is received on the primary channel for the BSS corresponding to the device within a specific time interval after receiving a PHY-RXEND.indication primitive corresponding to the ICF on the primary channel for the BSS corresponding to the device, and The above specific time interval is a time interval corresponding to NAVTimeout.

6. In paragraph 3, The TXOP for the above NPCA is included in the operating time interval for the above NPCA, The time interval of TXOP for the above NPCA is greater than or equal to the preset minimum time interval, After the termination of the TXOP for the NPCA, if it is identified that acquisition of the next TXOP for the NPCA having a time interval greater than or equal to the preset minimum time interval is possible on the NPCA primary channel based on the remaining time interval of the operation time interval for the NPCA, the next TXOP for the NPCA is acquired based on the EDCA, A method in which, after the termination of the TXOP for the NPCA, it is determined that acquisition of the next TXOP for the NPCA having a time interval greater than or equal to the preset minimum time interval is impossible on the NPCA primary channel based on the remaining time interval of the operation time interval for the NPCA, the NPCA primary channel is switched to the primary channel for the BSS corresponding to the device.

7. In paragraph 1, The above trigger frame includes the ICF transmitted first after the initiation of the TXOP for the NPCA, A method in which the first transmitted ICF includes a CS (carrier sense) required subfield, and an ICR is transmitted in response to the first transmitted ICF when the NPCA primary channel is identified as being idle based on the CS required subfield.

8. In paragraph 1, A method wherein the above device is an NPCA AP (access point) supporting the above NPCA.

9. In the device of the wireless LAN (local access network) system, Transmitter and receiver; and A processor connected to the transceiver, the processor comprising: Initiating a transmission opportunity (TXOP) for NPCA on an NPCA primary channel for non-primary channel access (NPCA) based on enhanced distributed channel access (EDCA); Setting up a trigger frame, wherein the trigger frame includes a Special User Info field and the B37 bit of the Special User Info field includes a 1-bit indication related to the NPCA; and A device configured to transmit the trigger frame based on the NPCA primary channel after initiating a TXOP for the NPCA.

10. In paragraph 9, A device wherein the above 1-bit instruction is set to indicate that the device performs an operation related to the NPCA.

11. In paragraph 9, A device wherein the processor is configured to set an operating time interval for the NPCA based on a time required to switch from the NPCA primary channel to a primary channel for a basic service set (BSS) corresponding to the device.

12. In paragraph 11, After identifying a PPDU (physical layer protocol data unit) or TXOP related to a BSS other than the BSS corresponding to the device on the primary channel for the BSS corresponding to the device, an operation time interval for the NPCA is set, The time interval of the PPDU related to the above other BSS is greater than or equal to a preset threshold, The above preset threshold is set to be greater than or equal to the sum of (i) the transmission time for the exchange between a specific control frame and a response and (ii) the transmission time for the exchange between specific data and one or more of an ACK (acknowledgement) or a block ACK.

13. In paragraph 12, If a TXOP related to the other BSS is identified, an operation time interval for the NPCA is set after detecting a preamble of a first PPDU received on the primary channel for the BSS corresponding to the device after a control frame exchange including an ICF corresponding to the PHY-RXEND.indication primitive is received on the primary channel for the BSS corresponding to the device within a specific time interval after receiving a PHY-RXEND.indication primitive corresponding to the ICF on the primary channel for the BSS corresponding to the device, and The above specific time interval is a time interval corresponding to NAVTimeout, device.

14. In paragraph 11, The TXOP for the above NPCA is included in the operating time interval for the above NPCA, The time interval of TXOP for the above NPCA is greater than or equal to the preset minimum time interval, After the termination of the TXOP for the NPCA, if it is identified that acquisition of the next TXOP for the NPCA having a time interval greater than or equal to the preset minimum time interval is possible on the NPCA primary channel based on the remaining time interval of the operation time interval for the NPCA, the next TXOP for the NPCA is acquired based on the EDCA, A device, wherein, after the termination of the TXOP for the NPCA, if it is determined that acquisition of the next TXOP for the NPCA having a time interval greater than or equal to the preset minimum time interval is impossible on the NPCA primary channel based on the remaining time interval of the operation time interval for the NPCA, the device switches from the NPCA primary channel to the primary channel for the BSS corresponding to the device.

15. In paragraph 9, The above trigger frame includes the ICF transmitted first after the initiation of the TXOP for the NPCA, A device instructed to transmit an ICR, which is a response to the first transmitted ICF, when the first transmitted ICF includes a CS (carrier sense) required subfield and the NPCA primary channel is identified as being idle based on the CS required subfield.

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