Method and apparatus for non-primary channel access in wireless LAN system

Abstract

The present disclosure relates to an improved wireless LAN system. The present disclosure proposes a method and an apparatus that consider NPCA in an improved wireless LAN system. Specifically, the present disclosure relates to a method performed by an STA of a wireless LAN system, the method comprising the steps of: receiving, from an AP, a first frame for initiating a TXOP on a secondary channel; and transmitting, to the AP, a second frame including feedback information related to NPCA for the TXOP.

Description

Method and device for auxiliary channel access in a wireless LAN system

[0001] The present disclosure relates to a wireless local area network (WLAN) system. Specifically, the present disclosure relates to a method and device for operating non-primary channel access (NPCA) in a WLAN system.

[0002] Wireless LAN (WLAN) systems are evolving for various purposes, such as improving transmission rates, increasing bandwidth, enhancing reliability, reducing errors, and reducing latency. The Institute of Electrical and Electronics Engineers (IEEE) publishes the 802.11 standard specification for WLAN systems, and the technology described in the 802.11 standard specification can be called WiFi (or Wi-Fi, Wireless Fidelity).

[0003] Wi-Fi technology has evolved over several generations of the 802.11 standard. For example, the 802.11ac standard addresses improvements for very high throughput (VHT), the 802.11ax standard addresses improvements for high efficiency (HE), and the 802.11be standard addresses improvements for extreme high throughput (EHT).

[0004] Meanwhile, technologies to provide a more improved wireless communication environment in wireless LAN systems are being discussed, and various technologies are being proposed and researched in response to the demand to further increase the reliability of wireless LAN systems.

[0005] The present disclosure proposes a method and device for accessing a non-primary channel in a wireless LAN system. Specifically, the present disclosure proposes procedures for transmitting information regarding non-primary channel access (NPCA) to enable a device to be scheduled when an adjacent basic service set (BSS) occupies the primary channel. Furthermore, the present disclosure proposes a frame structure for transmitting information regarding NPCA.

[0006] The technical objectives to be achieved in the present disclosure are not limited to those mentioned above, and other technical tasks not mentioned can be considered by a person having ordinary skill in the art to which the present invention pertains from the embodiments of the present invention described below.

[0007] According to one embodiment of the present disclosure, a method performed by a station (STA) of a wireless local area network (WLAN) system comprises the steps of: receiving, from an access point (AP), a first frame for initiating a transmission opportunity (TXOP) on a secondary channel; and transmitting, to the AP, a second frame including feedback information for non-primary channel access (NPCA) for the TXOP, wherein the second frame may include a first field for an association identifier (AID), a second field and a third field for indicating the feedback information, and a fourth field including parameters related to the NPCA.

[0008] According to one embodiment of the present disclosure, a method performed by an access point (AP) of a wireless local area network (WLAN) system includes the steps of transmitting, to a station (STA), a first frame for initiating a transmission opportunity (TXOP) on a secondary channel, and receiving, from the STA, a second frame including feedback information for a non-primary channel access (NPCA) for the TXOP, wherein the second frame may include a first field for an association identifier (AID), a second field and a third field for indicating the feedback information, and a fourth field including parameters related to the NPCA.

[0009] According to one embodiment of the present disclosure, a station (STA) of a wireless local area network (WLAN) system comprises a transceiver and at least one processor connected to the transceiver, wherein the at least one processor is configured to: receive, from an access point (AP), a first frame for initiating a transmission opportunity (TXOP) on a secondary channel, and transmit, to the AP, a second frame including feedback information for non-primary channel access (NPCA) for the TXOP, wherein the second frame may include a first field for an association identifier (AID), a second field and a third field for indicating the feedback information, and a fourth field including parameters related to the NPCA.

[0010] According to one embodiment of the present disclosure, an access point (AP) of a wireless local area network (WLAN) system comprises a transceiver and at least one processor connected to the transceiver, wherein the at least one processor is configured to: transmit, to a station (STA), a first frame for initiating a transmission opportunity (TXOP) on a secondary channel, and receive, from the STA, a second frame including feedback information for non-primary channel access (NPCA) for the TXOP, wherein the second frame may include a first field for an association identifier (AID), a second field and a third field for indicating the feedback information, and a fourth field including parameters related to the NPCA.

[0011] According to various embodiments proposed in this disclosure, the reliability of traffic transmission and reception between devices can be improved through coordination of NPCA in a wireless LAN system. Furthermore, resource waste can be reduced through efficient scheduling of non-AP (access point) STAs (stations) within a BSS (basic service set) based on NPCA information.

[0012] FIG. 1 illustrates a configuration of a device for wireless communication according to one embodiment of the present disclosure.

[0013] FIG. 2 illustrates an exemplary structure of a wireless LAN system related to the present disclosure.

[0014] Figure 3 illustrates a link setup process related to the present disclosure.

[0015] Figure 4 illustrates a backoff operation related to the present disclosure.

[0016] FIG. 5 illustrates a frame transmission operation based on CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) in connection with the present disclosure.

[0017] FIG. 6 illustrates an exemplary format of a frame used in a wireless LAN system related to the present disclosure.

[0018] FIG. 7 illustrates an exemplary format of a physical layer protocol data unit (PPDU) of a wireless LAN system related to the present disclosure.

[0019] FIG. 8 illustrates another exemplary format of a PPDU of a wireless LAN system related to the present disclosure.

[0020] FIG. 9 illustrates the configuration of a primary channel and a secondary channel of a wireless LAN system related to the present disclosure.

[0021] FIG. 10 illustrates the configuration of a primary channel and a secondary channel of a wireless LAN system related to the present disclosure.

[0022] Figure 11 illustrates the concept of NPCA (non-primary channel access) in a wireless LAN system related to the present disclosure.

[0023] Figure 12 illustrates a method of NPCA in a wireless LAN system related to the present disclosure.

[0024] FIG. 13a illustrates an exemplary format of a multi-station block Ack (M-BA) frame in a wireless LAN system according to an embodiment of the present disclosure.

[0025] FIG. 13b is a diagram illustrating an example of fields included in an M-BA frame related to the present disclosure.

[0026] FIG. 14 is a diagram illustrating an exemplary format of a field included in a frame according to one embodiment of the present disclosure.

[0027] FIG. 15 illustrates a format including NPCA feedback information in a wireless LAN system according to an embodiment of the present disclosure.

[0028] FIG. 16 illustrates a method for transmitting NPCA feedback information using a multi-TID (traffic identifier) ​​block Ack in a wireless LAN system according to an embodiment of the present disclosure.

[0029] FIG. 17 illustrates a method for transmitting NPCA feedback information using M-BA in a wireless LAN system according to an embodiment of the present disclosure.

[0030] FIG. 18 is a diagram illustrating an exemplary format of a field included in a frame according to one embodiment of the present disclosure.

[0031] FIG. 19 illustrates a format including BSS information in a wireless LAN system according to an embodiment of the present disclosure.

[0032] FIG. 20 illustrates a method for transmitting BSS (basic service set) information using M-BA in a wireless LAN system according to an embodiment of the present disclosure.

[0033] FIG. 21 illustrates a flowchart of operations for transmitting NPCA feedback information in a wireless LAN system according to one embodiment of the present disclosure.

[0034] FIG. 22 illustrates a flowchart of operations for transmitting NPCA feedback information in a wireless LAN system according to one embodiment of the present disclosure.

[0035] FIG. 23 illustrates a flowchart of operations for transmitting BSS information in a wireless LAN system according to an embodiment of the present disclosure.

[0036] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the attached drawings. It should be noted that, where possible, identical components are represented by identical reference numerals throughout the attached drawings. Furthermore, detailed descriptions of well-known functions and configurations that may obscure the gist of the present disclosure will be omitted.

[0037] In describing the embodiments in this specification, descriptions of technical details that are well known in the technical field to which the present disclosure pertains and are not directly related to the present disclosure will be omitted. This is to avoid obscuring the gist of the present disclosure by omitting unnecessary explanations and to convey the gist more clearly.

[0038] 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.

[0039] 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 with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided solely to ensure that the disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined solely by the scope of the claims.

[0040] At this time, it will be understood that each block of the 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). 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, and 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 provide steps for performing the functions described in the flowchart block(s).

[0041] 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.

[0042] Here, the term '~ unit' used in the present embodiment means a software or hardware component such as an FPGA or ASIC, 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, as an example, 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, components and '~parts' may be implemented to regenerate one or more CPUs within a device or secure multimedia card.

[0043] In the present disclosure, when a component is said to be "connected," "coupled," or "connected" to another component, this may include not only a direct connection but also an indirect connection in which another component exists between them. Furthermore, the terms "comprises" or "has" in the present disclosure specify the presence of the mentioned features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0044] In this disclosure, terms such as "first," "second," etc. are used only to distinguish one component from another, are not used to limit the components, and do not limit the order or importance of components unless specifically stated otherwise. Accordingly, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

[0045] The terminology used herein is for the purpose of describing particular embodiments and is not intended to limit the scope of the claims. As used in the description of the embodiments and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. The term "and / or" as used herein may refer to any one of the associated enumerated items, or is meant to refer to and encompass any and all possible combinations of two or more of them. Furthermore, the use of " / " between words in this disclosure has the same meaning as "and / or" unless otherwise stated.

[0046] The examples of the present disclosure can be applied to various wireless communication systems. For example, the examples of the present disclosure can be applied to a wireless LAN system. For example, the examples of the present disclosure can be applied to a wireless LAN system based on the IEEE 802.11a / g / n / ac / ax / be standards. Furthermore, the examples of the present disclosure can be applied to a wireless LAN system based on the newly discussed IEEE 802.11bn (or UHR (ultra high reliability)) standards. Furthermore, the examples of the present disclosure can be applied to a wireless LAN system based on the next-generation standards after IEEE 802.11bn.

[0047] Additionally, examples of the present disclosure may be applied to cellular wireless communication systems. For example, examples of the present disclosure may be applied to cellular wireless communication systems based on Long Term Evolution (LTE), LTE-Advanced (LTE-A), and New Radio (NR) technologies based on 3rd Generation Partnership Project (3GPP) standard documents.

[0048] FIG. 1 illustrates a configuration of a device for wireless communication according to one embodiment of the present disclosure.

[0049] The first device (100) and the second device (200) of FIG. 1 may be replaced with various terms such as terminal, wireless device, WTRU (Wireless Transmit and Receive Unit), UE (User Equipment), MS (Mobile Station), UT (user terminal), MSS (Mobile Subscriber Station), MSS (Mobile Subscriber Unit), SS (Subscriber Station), AMS (Advanced Mobile Station), WT (Wireless terminal), client terminal, or simply user.

[0050] In addition, the first device (100) and the second device (200) may be replaced with various terms such as access point (AP), base station (BS), fixed station, Node B, base transceiver system (BTS), network, artificial intelligence (AI) system, road side unit (RSU), repeater, router, relay, gateway, etc.

[0051] The devices (100, 200) illustrated in FIG. 1 may also be referred to as stations (STAs). For example, the devices (100, 200) illustrated in FIG. 1 may be referred to by various terms such as transmitting device, receiving device, transmitting STA, and receiving STA. For example, the STAs (110, 200) may perform an AP (access point) role or a non-AP role. That is, in the present disclosure, the STAs (110, 200) may perform the functions of an AP and / or a non-AP. When the STAs (110, 200) perform an AP function, they may simply be referred to as APs, and when the STAs (110, 200) perform a non-AP function, they may simply be referred to as STAs. In addition, in the present disclosure, the APs may also be referred to as AP STAs.

[0052] Referring to FIG. 1, the first device (100) and the second device (200) can transmit and / or receive wireless signals through various wireless LAN technologies (e.g., technologies based on the IEEE 802.11 standard document). The first device (100) and the second device (200) can include interfaces for a medium access control (MAC) layer and a physical (PHY) layer that follow the regulations of the IEEE 802.11 standard document.

[0053] In addition, the first device (100) and the second device (200) may additionally support various wireless communication technologies other than wireless LAN technology (for example, technologies based on 3GPP LTE, LTE-A, or NR standard documents). In addition, the devices of the present disclosure may be implemented as various devices such as mobile phones, vehicles, personal computers, AR (Augmented Reality) equipment, VR (Virtual Reality) equipment, etc. In addition, the STA of the present specification may support various communication services such as voice calls, video calls, data communications, autonomous driving, MTC (Machine-Type Communication), M2M (Machine-to-Machine), D2D (Device-to-Device), and IoT (Internet-of-Things).

[0054] A first device (100) includes one or more processors (102) and one or more memories (104), and may further include one or more transceivers (or transceivers) (106) and / or one or more antennas (108). The processor (102) controls the memories (104) and / or the transceivers (106), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure. For example, the processor (102) may process information in the memories (104) to generate first information and / or a first signal, and then transmit a wireless signal including the first information and / or the first signal via the transceivers (106). In addition, the processor (102) may receive a wireless signal including second information and / or a second signal through the transceiver (106), and then store information obtained through signal processing of the second information and / or the second signal in the memory (104). The memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, the memory (104) may perform some or all of the processes controlled by the processor (102), or may store software code including instructions for performing the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in the present disclosure. Here, the processor (102) and the memory (104) may be part of a communication modem / circuit / chip designed to implement a wireless LAN technology (e.g., a technology based on the IEEE 802.11 document). A transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals via one or more antennas (108). The transceiver (106) may include a transmitter and / or a receiver. The transceiver (106) may be used interchangeably with an RF (Radio Frequency) unit.

[0055] The second device (200) includes one or more processors (202) and one or more memories (204), and may further include one or more transceivers (or transceiver units) (206) and / or one or more antennas (208). The processor (202) controls the memories (204) and / or the transceivers (206), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure. For example, the processor (202) may process information in the memories (204) to generate third information and / or a third signal, and then transmit a wireless signal including the third information and / or the third signal via the transceivers (206). In addition, the processor (202) may receive a wireless signal including the fourth information and / or the fourth signal through the transceiver (206), and then store information obtained through signal processing of the fourth information and / or the fourth signal in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may perform some or all of the processes controlled by the processor (202), or store software code including instructions for performing the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in the present disclosure. Here, the processor (202) and the memory (204) may be part of a communication modem / circuit / chip designed to implement a wireless LAN technology (e.g., a technology based on the IEEE 802.11 document). A transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals via one or more antennas (208). The transceiver (206) may include a transmitter and / or a receiver. The transceiver (206) may be used interchangeably with an RF unit.

[0056] Hereinafter, hardware elements of the device (100, 200) will be described in more detail. Although not limited to the following, operations of one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement operations of one or more layers (e.g., functional layers such as PHY, MAC). One or more processors (102, 202) may generate one or more Protocol Data Units (PDUs) and / or one or more Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in the present disclosure. One or more processors (102, 202) may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in the present disclosure. One or more processors (102, 202) can generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, traffic or information according to the functions, procedures, proposals and / or methods disclosed in this disclosure, and provide the signals to one or more transceivers (106, 206). One or more processors (102, 202) can receive signals (e.g., baseband signals) from one or more transceivers (106, 206) and obtain PDUs, SDUs, messages, control information, data, traffic or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed in this disclosure.

[0057] One or more memories (104, 204) may be coupled to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. The one or more memories (104, 204) may be configured as read only memory (ROM), random access memory (RAM), erasable programmable ROM (EPROM), electronically EPROM (EEPROM), flash memory, hard drives, registers, cache memory, computer readable storage media, and / or combinations thereof. The one or more memories (104, 204) may be located internally and / or externally to the one or more processors (102, 202). Additionally, the one or more memories (104, 204) may be coupled to the one or more processors (102, 202) via various technologies, such as wired or wireless connections.

[0058] One or more transceivers (106, 206) can transmit user data, control information, data, traffic, wireless signals, and / or channels, etc., as described in the methods and / or flowcharts of the present disclosure, to one or more other devices. One or more transceivers (106, 206) can receive user data, control information, data, traffic, wireless signals, and / or channels, etc., as described in the descriptions, functions, procedures, proposals, methods, and / or flowcharts of the present disclosure, from one or more other devices. For example, one or more transceivers (106, 206) can be coupled to one or more processors (102, 202) and can transmit and receive wireless signals. For example, one or more processors (102, 202) can control one or more transceivers (106, 206) to transmit user data, control information, traffic, wireless signals, and / or channels, etc., to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, traffic, wireless signals, and / or channels from one or more other devices. Additionally, one or more transceivers (106, 206) may be coupled to one or more antennas (108, 208), and one or more transceivers (106, 206) may be configured to transmit and receive user data, control information, traffic, wireless signals, and / or channels, etc., as described in the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure, via one or more antennas (108, 208). In the present disclosure, one or more antennas (108, 208) may be multiple physical antennas or multiple logical antennas (e.g., antenna ports).One or more transceivers (106, 206) may convert received user data, control information, wireless signals / channels, etc. from RF band signals to baseband signals in order to process the received user data, control information, wireless signals / channels, etc. using one or more processors (102, 202). One or more transceivers (106, 206) may convert processed user data, control information, wireless signals / channels, etc. from baseband signals to RF band signals using one or more processors (102, 202). For this purpose, one or more transceivers (106, 206) may include an (analog) oscillator and / or a filter.

[0059] In one example, one of the devices (100, 200) may perform the intended operation of an AP, and the other of the devices (100, 200) may perform the intended operation of a non-AP STA. In another example, the transceiver (106, 206) of FIG. 1 may perform transmission and / or reception operations of signals (e.g., packets or PPDUs (physical layer protocol data units) according to IEEE 802.11a / b / g / n / ac / ax / be / bn, etc.).

[0060] Additionally, in the present disclosure, the operations of various STAs generating transmission / reception signals or performing data processing or calculations in advance for transmission / reception signals can be performed in the processor (102, 202) of FIG. 1. For example, an example of an operation of generating a transmission / reception signal or performing data processing or operation in advance for a transmission / reception signal is an operation of determining / obtaining / configuring / computing / decoding / encoding bit information of a field included in a PPDU (e.g., SIG (signal), STF (short training field), LTF (long training field), Data, etc.), 2) determining / configuring / obtaining time resources or frequency resources (e.g., subcarrier resources) used for a field included in a PPDU (e.g., SIG, STF, LTF, Data, etc.), 3) determining / configuring / obtaining a specific sequence (e.g., pilot sequence, STF / LTF sequence, extra sequence applied to SIG) used for a field included in a PPDU (e.g., SIG, STF, LTF, Data, etc.), 4) power control operation and / or power saving operation applied to an STA, 5) ACK (acknowledgement) signal It may include operations related to decision / acquisition / configuration / computation / decoding / encoding, etc. In addition, in the example below, various information (e.g., information related to fields / subfields / control fields / parameters / power, etc.) used by various STAs for decision / acquisition / configuration / computation / decoding / encoding of transmission / reception signals may be stored in the memory (104, 204) of FIG. 1.

[0061] Hereinafter, downlink (DL) refers to a link for communication from an AP STA to a non-AP STA, and downlink PPDUs / packets / signals, etc. can be transmitted and received through the downlink. In downlink communication, the transmitter may be part of an AP STA, and the receiver may be part of a non-AP STA. Uplink (UL) refers to a link for communication from a non-AP STA to an AP STA, and uplink PPDUs / packets / signals, etc. can be transmitted and received through the uplink. In uplink communication, the transmitter may be part of a non-AP STA, and the receiver may be part of an AP STA.

[0062] FIG. 2 illustrates an exemplary structure of a wireless LAN system related to the present disclosure.

[0063] A wireless LAN system may have a structure composed of multiple components. The wireless LAN system can support transparent STA mobility to the upper layer through the interaction of the multiple components. A Basic Service Set (BSS) corresponds to a basic building block of a wireless LAN. FIG. 2 illustrates, by way of example, the existence of two BSSs (BSS 1 and BSS 2), and the inclusion of two STAs as members of each BSS (STA 1 and STA 2 are included in BSS 1, and STA 3 and STA 4 are included in BSS 2). The oval representing a BSS in FIG. 2 can also be understood as representing a coverage area in which STAs included in the corresponding BSS maintain communication. This area can be referred to as a Basic Service Area (BSA). When an STA moves outside of the BSA, it cannot directly communicate with other STAs within the BSA.

[0064] If we do not consider the distributed system (DS) illustrated in Fig. 2, the most basic type of BSS in a wireless LAN is an Independent BSS (IBSS). For example, an IBSS can have a minimal form consisting of only two STAs. For example, assuming other components are omitted, BSS 1 consisting of only STA 1 and STA 2, or BSS 2 consisting of only STA 3 and STA 4, can be representative examples of an IBSS, respectively. Such a configuration is possible when the STAs can communicate directly without an AP. Furthermore, this type of WLAN is not planned in advance but can be configured when a local area network (LAN) is required, and can also be called an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. That is, in an IBSS, STAs are managed in a distributed manner. In IBSS, all STAs can be mobile STAs, and access to the DS is not permitted, forming a self-contained network.

[0065] An STA's membership in a BSS can dynamically change, for example, when an STA is turned on or off, or when an STA enters or leaves a BSS area. To become a member of a BSS, an STA can join the BSS using a synchronization process. To access all services in the BSS infrastructure, an STA must be associated with the BSS. This association can be dynamically established and may involve the use of a Distribution System Service (DSS).

[0066] In a wireless LAN, the direct STA-to-STA distance may be limited by PHY performance. While this distance limit may be sufficient in some cases, communication between STAs over longer distances may be required in other cases. To support extended coverage, a DS can be configured.

[0067] DS refers to a structure in which BSSs are interconnected. Specifically, a BSS may exist as an extended component of a network composed of multiple BSSs, as illustrated in Figure 2. DS is a logical concept and can be specified by the characteristics of the distributed system medium (DSM, DS medium). In this regard, the Wireless Medium (WM) and DSM can be logically distinguished. Each logical medium is used for a different purpose and by different components. These media are neither limited to being identical nor limited to being different. This logical difference between multiple media explains the flexibility of the WLAN architecture (DS architecture or other network architectures). In other words, the WLAN architecture can be implemented in various ways, and the physical characteristics of each implementation can independently specify the WLAN architecture.

[0068] A DS can support mobile devices by providing seamless integration of multiple BSSs and the logical services necessary to handle addresses to destinations. Additionally, a DS may further include a component called a portal, which acts as a bridge for connecting wireless LANs to other networks (e.g., IEEE 802.X).

[0069] An AP enables non-AP STAs associated with it to access the DS through the WM. An AP may refer to an entity that also has the functionality of an STA, and data movement between the BSS and the DS may be performed through the AP. For example, STA 2 and STA 3 illustrated in FIG. 2 have the functionality of an STA and provide the function of allowing associated non-AP STAs (STA 1 and STA 4) to access the DS. In addition, since all APs are basically STAs, all APs are addressable entities. The address used by an AP for communication on the WM and the address used by an AP for communication on the DSM do not necessarily have to be the same. A BSS consisting of an AP and one or more STAs may be referred to as an infrastructure BSS.

[0070] Data transmitted from one of the STA(s) associated with an AP to the STA address of that AP is always received on an uncontrolled port and can be processed by an IEEE 802.1X port access entity. In addition, if the controlled port is authenticated, the transmitted data (or frame) can be forwarded to the DS.

[0071] In addition to the structure of the DS described above, an extended service set (ESS) may be established to provide wider coverage.

[0072] An ESS is a network of arbitrary size and complexity, and may correspond to a set of BSSs connected to a DS. However, an ESS does not include a DS. An ESS network is characterized by appearing as an IBSS at the LLC (Logical Link Control) layer. STAs included in an ESS can communicate with each other, and mobile STAs can move from one BSS to another (i.e., within the same ESS) transparently to the LLC. APs included in an ESS may have the same SSID (service set identifier). The SSID is distinct from the BSS ID (BSS SSID), which is the identifier of the BSS.

[0073] In a wireless LAN system, no assumptions are made about the relative physical locations of BSSs, and all of the following configurations are possible: BSSs can be partially overlapping, which is commonly used to provide continuous coverage. BSSs can also be physically disconnected, and there is no logical distance restriction between them. BSSs can also be physically co-located, which can be used to provide redundancy. Furthermore, one or more IBSS or ESS networks can physically co-exist in the same space as one (or more) ESS networks. This can occur in cases where an ad-hoc network operates in the same location as an ESS network, where physically overlapping wireless networks are configured by different organizations, or where two or more different access and security policies are required at the same location.

[0074] Figure 3 illustrates a link setup process related to the present disclosure.

[0075] For an STA to set up a link and transmit and receive data on a network, it must discover the network via an AP, perform authentication, establish an association, and establish security. 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.

[0076] At step 310, the STA may perform a network discovery operation. This network discovery operation may include scanning operations by the STA. That is, for the STA to access a network, it must search for available networks. Before joining a wireless network, the STA must identify compatible networks. The process of identifying networks in a specific area is called scanning.

[0077] Scanning methods include active scanning and passive scanning. Figure 3 illustrates a network discovery operation that includes an active scanning process as an example. In active scanning, an STA performing scanning transmits a probe request frame to discover any APs in the vicinity while moving between channels and waits for a response. The responder transmits a probe response frame in response to the STA that transmitted the probe request frame. Here, the responder may be the STA that last transmitted a beacon frame in the BSS of the channel being scanned. In the BSS, the AP transmits the beacon frame, so the AP becomes the responder. In the IBSS, the STAs within the IBSS take turns transmitting beacon frames, so the responder is not fixed. For example, an STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 can store BSS-related information included in the received probe response frame and move to the next channel (e.g., channel 2) to perform scanning (i.e., transmitting and receiving probe requests / responses on channel 2) in the same manner.

[0078] Although not shown in Figure 3, the scanning operation can also be performed in a passive scanning manner. In passive scanning, the STA performing the scanning moves between channels and waits for a beacon frame. A beacon frame is one of the management frames defined in IEEE 802.11. It announces the existence of a wireless network and is periodically transmitted to enable the STA performing the scanning to find the wireless network and participate in the wireless network. In the BSS, the AP performs the role of periodically transmitting the beacon frame, and in the IBSS, the STAs within the IBSS take turns transmitting the beacon frame. When the STA performing the scanning receives a beacon frame, it stores the information about the BSS included in the beacon frame and moves to another channel, recording the beacon frame information on each channel. The STA receiving the beacon frame stores the BSS-related information included in the received beacon frame and moves to the next channel to perform scanning on the next channel in the same manner. Comparing active scanning and passive scanning, active scanning has the advantage of lower delay and power consumption than passive scanning.

[0079] After the STA discovers the network, an authentication process may be performed at step 320. This authentication process may be referred to as the first authentication process to clearly distinguish it from the security setup operation of step 340 described below.

[0080] The authentication process involves the STA sending an authentication request frame to the AP, and the AP responding by sending an authentication response frame to the STA. The authentication request frame and the authorization response frame used in the authentication process belong to management frames.

[0081] 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.

[0082] An STA can transmit an authentication request frame to an AP. The AP can determine whether to grant authentication to the STA based on the information contained in the received authentication request frame. The AP can provide the result of the authentication process to the STA via an authentication response frame.

[0083] After the STA is successfully authenticated, an association process may be performed at step 330. The association process includes a process in which the STA transmits an association request frame to the AP, and in response, the AP transmits an association response frame to the STA.

[0084] The association request frame may include information about various capabilities, a beacon listen interval, a service set identifier (SSID), supported rates, supported channels, a robust security network (RSN), a mobility domain, supported operating classes, a Traffic Indication Map Broadcast request, interworking service capabilities, etc. For example, the association response frame may include information about various capabilities, a status code, an Association ID (AID), supported rates, an Enhanced Distributed Channel Access (EDCA) parameter set, a Received Channel Power Indicator (RCPI), a Received Signal to Noise Indicator (RSNI), a mobility domain, a timeout interval (e.g., an association comeback time), overlapping BSS scan parameters, a TIM broadcast response, a Quality of Service (QoS) map, etc. These are just some examples of information that may be included in a combined request / response frame, and the combined request / response frame may further include additional information.

[0085] After the STA successfully joins the network via the AP, a security setup process may be performed at step 340. The security setup process of step 340 may include an authentication process via a Robust Security Network Association (RSNA) request / response. Furthermore, if the authentication process of step 320 is referred to as the first authentication process, the security setup process of step 340 may also be referred to simply as the authentication process.

[0086] The security setup process of step 340 may include, for example, a process of establishing a private key through a four-way handshaking using an Extensible Authentication Protocol over LAN (EAPOL) frame. Furthermore, the security setup process may be performed according to a security method not defined in the IEEE 802.11 standard.

[0087] Figure 4 illustrates a backoff operation related to the present disclosure.

[0088] In wireless LAN systems, the basic MAC access mechanism is Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA). CSMA / CA, also known as the Distributed Coordination Function (DCF) of the IEEE 802.11 MAC, essentially employs a "listen before talk" access mechanism. According to this type of access mechanism, the AP and / or STA performs Clear Channel Assessment (CCA) to sense the wireless channel or medium for a predetermined time period (e.g., DIFS (DCF Inter-Frame Space)) before starting transmission. If the sensing result determines that the medium is in an idle state, the AP and / or STA starts transmitting frames through the medium. On the other hand, if the medium is detected to be occupied or busy, the AP and / or STA may not start its own transmission, but may wait for a predetermined delay period (e.g., a random backoff period) for medium access before attempting to transmit frames. By applying the random backoff period, multiple STAs may attempt to transmit frames after waiting for different periods of time, thereby minimizing collisions.

[0089] Additionally, the IEEE 802.11 MAC protocol provides a Hybrid Coordination Function (HCF). HCF is based on the DCF and Point Coordination Function (PCF). PCF is a polling-based synchronous access method, which refers to a method in which all receiving APs and / or STAs periodically poll to ensure that they can receive data frames. HCF also includes Enhanced Distributed Channel Access (EDCA) and HCF Controlled Channel Access (HCCA). EDCA is a contention-based access method in which a provider provides data frames to multiple users, while HCCA is a contention-free channel access method that utilizes a polling mechanism. In addition, HCF includes a medium access mechanism to improve the Quality of Service (QoS) of a wireless LAN, and can transmit QoS data in both a Contention Period (CP) and a Contention Free Period (CFP).

[0090] Referring to Fig. 4, an operation based on a random backoff period is described. When an occupied / busy medium changes to an idle state, multiple STAs may attempt to transmit data (or frames). To minimize collisions, each STA may select a random backoff count, wait for the corresponding slot time, and then attempt transmission. The random backoff count has a pseudo-random integer value and may be determined as one of the values ​​in the range of 0 to CW. Here, CW is a contention window parameter value. The CW parameter is initially given a value of CWmin, but in case of a transmission failure (e.g., if an ACK for a transmitted frame is not received), the STA may increase the CW by a factor of two. When the CW parameter value reaches CWmax, the STA may attempt data transmission while maintaining the CWmax value until the data transmission is successful, and if the data transmission is successful, the CW is reset to the CWmin value. The values ​​of CW, CWmin and CWmax can be set to 2n-1 (n=0, 1, 2, ...).

[0091] Once the random backoff process begins, the STA continues to monitor the medium while counting down the backoff slots according to the determined backoff count value. If the medium is monitored as occupied, the countdown stops and waits. When the medium becomes idle, the remaining countdown resumes.

[0092] In the example of FIG. 4, when a packet to be transmitted reaches the MAC of STA3, STA3 can immediately transmit the frame if it confirms that the medium is idle for DIFS. The remaining STAs monitor the medium for occupied / busy states and wait. In the meantime, data to be transmitted may also occur in each of STA1, STA2, and STA5, and each STA can count down the backoff slot according to the random backoff count value selected by each STA after waiting for DIFS if it confirms that the medium is idle. Assume that STA2 selects the smallest backoff count value and STA1 selects the largest backoff count value. In other words, this example shows a case where the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1 when STA2 finishes the backoff count and starts frame transmission. STA1 and STA5 briefly stop counting down and wait while STA2 occupies the medium. When STA2's occupation ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and then resume the backoff count that was stopped. That is, STA1 and STA5 can start transmitting frames after counting down the remaining backoff slots equal to the remaining backoff time. Since STA5's remaining backoff time is shorter than STA1's, STA5 starts transmitting frames. While STA2 occupies the medium, STA4 may also have data to transmit. When the medium becomes idle, STA4 waits for DIFS, counts down according to a random backoff count value of its choice, and then starts transmitting frames. In the example of FIG. 4, the remaining backoff time of STA5 coincidentally matches the random backoff count value of STA4, in which case a collision may occur between STA4 and STA5. If a collision occurs, neither STA4 nor STA5 will receive an ACK, resulting in a failure in data transmission.In this case, STA4 and STA5 can select a random backoff count value and perform a countdown after doubling the CW value. STA1 waits while the medium is occupied by transmissions from STA4 and STA5, and when the medium becomes idle, it waits for DIFS and can start transmitting frames after the remaining backoff time elapses.

[0093] As shown in the example of Fig. 4, a data frame is a frame used for transmitting data to an upper layer, and can be transmitted after a backoff performed after DIFS elapses from when the medium becomes idle. Additionally, a management frame is a frame used for exchanging management information without being transmitted to an upper layer, and is transmitted after a backoff performed after an IFS such as DIFS or PIFS (Point coordination function IFS) elapses. A management frame may include a beacon, an association request / response, a re-association request / response, a probe request / response, an authentication request / response, etc. as a subtype frame. A control frame is a frame used to control access to the medium. Control frames can include RTS (Request-To-Send), CTS (Clear-To-Send), ACK (Acknowledgment), PS-Poll (Power Save-Poll), Block ACK (B-ACK or BlockAck), Block ACK Request (BlockACKReq), NDP announcement (null data packet announcement), Trigger, etc. as subtype frames. If the control frame is not a response frame to the previous frame, it is transmitted after a backoff performed after the DIFS (Direct Inverse Frame Stop) has elapsed, and if it is a response frame to the previous frame, it is transmitted without a backoff performed after the SIFS (short IFS) has elapsed. The type and subtype of a frame can be identified by the type field and subtype field in the frame control (FC) field.

[0094] A QoS (Quality of Service) STA can transmit a frame after a backoff performed after the AIFS (arbitration IFS) for the access category (AC) to which the frame belongs, i.e., AIFS[i] (where i is a value determined by the AC), has elapsed. Here, the frames for which AIFS[i] can be used can be data frames, management frames, and also control frames that are not response frames.

[0095] FIG. 5 illustrates a frame transmission operation based on CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) in connection with the present disclosure.

[0096] As mentioned above, the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing, in which STAs 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 an STA can utilize a Network Allocation Vector (NAV). The NAV is a value that an STA that is currently using or has the right to use the medium indicates to other STAs the remaining time until the medium becomes available. Therefore, the value set as NAV corresponds to the period during which the STA transmitting the frame is scheduled to use the medium, and an STA that receives the NAV value is prohibited from accessing the medium during that period. For example, the NAV can be set based on the value of the "duration" field in the MAC header of the frame.

[0097] In the example of FIG. 5, STA1 wants to transmit data to STA2, and STA3 is in a position to overhear part or all of the frames transmitted and received between STA1 and STA2.

[0098] In order to reduce the possibility of collisions in transmissions of multiple STAs in a CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames may be applied. In the example of FIG. 5, while STA1 is transmitting, STA3 may determine that the medium is idle based on carrier sensing. That is, STA1 may correspond to a hidden node for STA3. Alternatively, in the example of FIG. 5, while STA2 is transmitting, STA3 may determine that the medium is idle based on carrier sensing. That is, STA2 may correspond to a hidden node for STA3. By exchanging RTS / CTS frames before performing data transmission and reception between STA1 and STA2, STAs outside the transmission range of either STA1 or STA2, or STAs outside the carrier sensing range for transmissions from STA1 or STA3, may not attempt to occupy the channel during data transmission and reception between STA1 and STA2.

[0099] Specifically, STA1 can determine whether a channel is occupied through carrier sensing. In terms of physical carrier sensing, STA1 can determine channel occupancy idleness based on the energy level or signal correlation detected in the channel. Furthermore, in terms of virtual carrier sensing, STA1 can determine the channel occupancy status using the NAV timer.

[0100] STA1 can transmit an RTS frame to STA2 after performing a backoff if the channel is idle during the DIFS. STA2 can transmit a CTS frame, which is a response to the RTS frame, to STA1 after an SIFS if it receives the RTS frame.

[0101] If STA3 cannot overhear a CTS frame from STA2 but can overhear an RTS frame from STA1, STA3 can use the duration information contained in the RTS frame to set a NAV timer for the subsequent consecutively transmitted frame transmission period (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame). Alternatively, if STA3 cannot overhear an RTS frame from STA1 but can overhear a CTS frame from STA2, STA3 can use the duration information contained in the CTS frame to set a NAV timer for the subsequent consecutively transmitted frame transmission period (e.g., SIFS + data frame + SIFS + ACK frame). That is, if STA3 can overhear one or more of the RTS or CTS frames from one or more of STA1 or STA2, it can set a NAV accordingly. If STA3 receives a new frame before the NAV timer expires, it can update the NAV timer using the duration information contained in the new frame. STA3 does not attempt channel access until the NAV timer expires.

[0102] If STA1 receives a CTS frame from STA2, it can transmit a data frame to STA2 after SIFS from the time when the CTS frame is completely received. If STA2 successfully receives the data frame, it can transmit an ACK frame in response to the data frame to STA1 after SIFS. STA3 can determine whether the channel is in use through carrier sensing if the NAV timer expires. If STA3 determines that the channel is not in use by another terminal during the DIFS after the NAV timer expires, it can attempt channel access after a contention window (CW) based on a random backoff has elapsed.

[0103] FIG. 6 illustrates an exemplary format of a frame used in a wireless LAN system related to the present disclosure.

[0104] Based on an instruction or primitive (meaning a set of instructions or parameters) from the MAC layer, the PHY layer can prepare an MPDU (MAC PDU) to be transmitted. When the PHY layer receives a command requesting the start of transmission from the MAC layer, the PHY layer can switch to transmission mode and transmit the information (e.g., data) provided by the MAC layer in the form of a frame. In addition, when the PHY layer detects a valid preamble of the received frame, it can monitor the header of the preamble and send a command to the MAC layer notifying the start of reception by the PHY layer.

[0105] In this way, information transmission / reception in a wireless LAN system is done in the form of frames, and for this purpose, the PHY layer Protocol Data Unit (PPDU) frame format is defined.

[0106] A basic PPDU frame may include 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 may consist of only L-STF (Legacy-STF), L-LTF (Legacy-LTF), a SIG field, and a data field. In addition, depending on the type of PPDU frame format (e.g., HT-mixed format PPDU, HT-greenfield format PPDU, VHT (very high throughput) PPDU, etc.), additional (or different types of) STF, LTF, and SIG fields may be included between the SIG field and the data field. Specific types of frame formats are described later in FIG. 7.

[0107] STF is a signal for signal detection, AGC (automatic gain control), diversity selection, precise time synchronization, etc., and LTF is a signal for channel estimation, frequency error estimation, etc. STF and LTF are signals for synchronization and channel estimation of the OFDM (orthogonal frequency division multiplexing) physical layer.

[0108] The SIG field may include a RATE field and a LENGTH field, among others. The RATE field may include information about the modulation and coding rate of the data. The LENGTH field may include information about the length of the data. Additionally, the SIG field may include a parity bit, a SIG TAIL bit, among others.

[0109] 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 to synchronize the descrambler at the receiving end. The PSDU corresponds to a MAC PDU 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.

[0110] MAC PDUs are defined according to various MAC frame formats, and a basic MAC frame consists of a MAC header, a frame body, and a frame check sequence (FCS). A MAC frame is composed of MAC PDUs and can be transmitted / received through the PSDU in the data portion of the PPDU frame format.

[0111] The MAC header includes a frame control field, a duration / ID field, an address field, etc. The frame control field may include control information necessary for frame transmission / reception. The duration / ID field may be set to the time for transmitting the corresponding frame, etc. The specific contents of the Sequence Control, QoS Control, and HT Control subfields of the MAC header are omitted.

[0112] Although not shown in FIG. 6, the null data packet (NDP) frame format refers to a frame format that does not include a data packet. That is, the NDP frame refers to a frame format that includes the PLCP (physical layer convergence procedure) header portion (i.e., STF, LTF, and SIG fields) of the general PPDU frame format, but does not include the remaining portion (i.e., data field). The NDP frame may also be referred to as a short frame format.

[0113] FIG. 7 illustrates an exemplary format of a physical layer protocol data unit (PPDU) of a wireless LAN system related to the present disclosure.

[0114] Standards such as IEEE 802.11a / g / n / ac / ax / be use various PPDU formats. The basic PPDU format (IEEE 802.11a / g format) includes L-LTF, L-STF, L-SIG, and Data fields. The basic PPDU format can also be referred to as the non-HT PPDU format.

[0115] The HT PPDU format (IEEE 802.11n format) additionally includes HT-SIG, HT-STF, and HT-LFT(s) fields in addition to the basic PPDU format. The HT PPDU format illustrated in Fig. 7 may be referred to as an HT-mixed format. Although not illustrated, an HT-greenfield format PPDU may be defined, which corresponds to a format that does not include L-STF, L-LTF, and L-SIG, and is composed of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTF, and Data fields.

[0116] The VHT PPDU format (IEEE 802.11ac format) includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in addition to the basic PPDU format.

[0117] The HE PPDU format (IEEE 802.11ax format) additionally includes RL-SIG (Repeated L-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), and PE (Packet Extension) fields in addition to the basic PPDU format. Depending on specific examples of the HE PPDU format, some fields may be excluded or their lengths may vary. For example, the HE-SIG-B field is included in the HE PPDU format for multi-users (MUs), but the HE PPDU format for single-users (SUs) does not include the HE-SIG-B. In addition, the HE trigger-based (TB) PPDU format does not include the HE-SIG-B, and the length of the HE-STF field may vary to 8 μs. The HE ER (Extended Range) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field can vary up to 16 μs.

[0118] FIG. 8 illustrates another exemplary format of a PPDU of a wireless LAN system related to the present disclosure.

[0119] The EHT PPDU format (IEEE 802.11be format) of FIG. 8 may include an EHT MU PPDU format and an EHT TB PPDU format. The EHT MU PPDU format corresponds to a PPDU that carries one or more data (or PSDU) for one or more users. The EHT MU PPDU can be used for both SU transmission and MU transmission, and the EHT MU PPDU may correspond to a PPDU for one receiving STA or multiple receiving STAs. The EHT TB PPDU omits the EHT-SIG compared to the EHT MU PPDU. An STA that receives a trigger for UL MU transmission (e.g., a trigger frame or an RTS frame) can perform UL transmission based on the EHT TB PPDU format.

[0120] The EHT PPDU format includes RL-SIG, U-SIG (Universal SIG), EHT-SIG, EHT-STF, EHT-LTF(s), and PE fields in addition to the basic PPDU format. Depending on the specific examples of the EHT PPDU format, some fields may be excluded or their lengths may vary. For example, depending on the EHT MU PPDU format and EHT TB PPDU format described above, some fields of the EHT PPDU format may or may not be included, or the lengths of specific fields may vary.

[0121] FIG. 9 illustrates the configuration of a primary channel and a secondary channel of a wireless LAN system related to the present disclosure.

[0122] Transmission channels in standards such as IEEE 802.11a / g / n / ac / ax / be can be configured with various bandwidths (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz). Referring to FIG. 9, the configuration of a channel in which the operating bandwidth of an AP is 80 MHz is illustrated. (For example, the operating bandwidth may include a primary 20 MHz (910), a secondary 20 MHz (920) adjacent to the primary 20 MHz (910), and a secondary 40 MHz (930). At this time, the primary 20 MHz (910) may be idle in order to access a wideband channel (e.g., a channel with a channel bandwidth greater than 20 MHz). Therefore, if the primary channel is being used by another AP, the AP cannot transmit using the idle secondary channel.

[0123] For example, if a PPDU is transmitted on the primary 20MHz (910) by another AP (e.g., an AP within a different BSS), the AP within the BSS cannot transmit using the remaining secondary channels (e.g., secondary 20MHz (920) and secondary 40MHz (930)). In this case, the use of the primary channel (e.g., primary 20MHz (910)) by PPDU transmission of another AP or an associated STA connected to another AP may be referred to as interference or overlapping basic service set (OBSS) transmission. In addition, the PPDU of another AP or an associated STA connected to another AP on the primary channel may be referred to as an OBSS PPDU. As another example, if a PPDU of another AP is transmitted on 40MHz including the primary 20MHz (910), the AP cannot transmit using the secondary 40MHz (930). Therefore, APs and non-AP STAs within a BSS can transmit and / or receive PPDUs only in the time domain of the primary channel where no OBSS exists.

[0124] FIG. 10 illustrates the configuration of a primary channel and a secondary channel of a wireless LAN system related to the present disclosure.

[0125] Referring to FIG. 10, when a primary channel (e.g., primary 20 MHz (1010)) is being used by another AP as in the aforementioned FIG. 9 and a secondary channel (e.g., secondary 20 MHz (1020) and / or secondary 40 MHz (1030)) is available, the AP and non-AP STAs can transmit and / or receive on the available secondary channels. For example, when an OBSS PPDU of 20 MHz exists on the primary channel, the AP and non-AP STAs can transmit and / or receive the PPDU on the secondary channels (e.g., secondary 20 MHz (1020) and secondary 40 MHz (1030)). Additionally, even if a 40MHz OBSS PPDU exists on the primary channel, the AP and non-AP STAs may transmit and / or receive the PPDU on the secondary channel (e.g., secondary 40MHz (1030)). In this case, the AP and non-AP STAs may be permitted to transmit and / or receive the PPDU using the secondary channel only in the time region occupied by the OBSS PPDU, based on the time information occupied by the OBSS PPDU.

[0126] Meanwhile, transmission using a secondary channel may be referred to as non-primary channel access (NPCA). For example, NPCA may refer to data transmission and reception on a continuous secondary channel (or non-primary channel (NPC)) excluding the bandwidth used by the OBSS from the operating bandwidth of the AP. Accordingly, a method is described below in which a non-AP STA transmits information regarding NPCA to the AP, and the AP performs scheduling for transmitting PPDUs to the non-AP STA based on this information.

[0127] Figure 11 illustrates the concept of NPCA (non-primary channel access) in a wireless LAN system related to the present disclosure.

[0128] Referring to FIG. 11, when the operating bandwidth of the AP is 160 MHz, the operating bandwidth may include a primary 80 MHz (hereinafter, P80) and a secondary 80 MHz (hereinafter, S80). At this time, when OBSS transmission (e.g., OBSS PPDU) uses P80, NPCA may be considered. For example, a non-AP STA or AP may receive an RTS frame from an OBSS AP or an OBSS non-AP STA during the process of participating in contention on a primary channel 20 MHz (P20). The OBSS non-AP STA or OBSS AP that receives the RTS frame may transmit a CTS frame in response to the RTS frame, and the non-AP STA or AP that receives the CTS frame may set a Basic NAV by referring to the duration field of the RTS and / or CTS frame. At this time, the basic NAV may be the time required for virtual carrier sensing to protect the PPDU transmission of the STA that has secured the transmission opportunity (TXOP). The non-AP STA or AP can identify the NPCA duration based on the basic NAV. The NPCA duration may be set to be shorter than the basic NAV by the switching delay (or switching latency). The switching delay may occur in the process of changing the channel to perform contention on a transmittable secondary channel during the process of performing NPCA. In the example of FIG. 11, the RTS and CTS frames may be the same as those described in FIG. 5 described above. In the above, the RTS frame and CTS frame related to the OBSS non-AP STA or OBSS AP may be referred to as the OBSS RTS frame and the OBSS CTS frame, respectively.

[0129] Meanwhile, when the NPCA duration is set based on the transmission of the OBSS RTS and / or CTS frames as described above, the NPCA AP and the NPCA non-AP STA may have the same basic NAV. The NPCA AP may refer to an AP capable of performing NPCA or an AP performing NPCA. The NPCA non-AP STA or NPCA STA may refer to an STA capable of performing NPCA or an STA performing NPCA. Within the NPCA duration, data between the NPCA AP and the NPCA non-AP STA may be transmitted and / or received through a secondary channel. On the other hand, when the OBSS transmission uses the entire operating bandwidth of the NPCA AP, data transmission and reception through NPCA may not be performed because there is no secondary channel for transmitting and receiving data during the OBSS transmission period.

[0130] Figure 12 illustrates an NPCA method in a wireless LAN system related to the present disclosure.

[0131] Referring to FIG. 12, specific operations of an NPCA AP and an NPCA STA for transmitting and receiving data via NPCA are described in chronological order. For example, below, an NPCA AP may have an operating bandwidth of 160 MHz (e.g., including P80 and S80), and NPCA STA(s) may have an operating bandwidth of 80 MHz or 160 MHz. In addition, below, an NPCA AP may refer to an AP capable of performing NPCA or an AP currently performing NPCA. An NPCA non-AP STA or NPCA STA may refer to an STA capable of performing NPCA or an STA currently performing NPCA. In addition, below, an NPCA AP and an NPCA STA may be referred to as an AP and a non-AP STA (or STA), respectively.

[0132] In one embodiment, non-AP STAs may participate in contention and attempt to access the primary channel (e.g., P80). Non-AP STAs (e.g., NPCA STAs) or APs (e.g., NPCA APs) may receive (or detect) an initial control frame (ICF) (e.g., OBSS ICF (1205)) from an OBSS AP or OBSS STA during the process of participating in contention on the primary channel 80 MHz (P80). In this case, the ICF may be a transmission opportunity (TXOP) or a control frame for initiating a sequence. A basic NAV may be set based on the ICF. In addition, the OBSS non-AP STA or OBSS AP that receives the ICF may transmit an initial control response (ICR) (e.g., OBSS ICR (1210)) to the OBSS AP or OBSS non-AP in response to the ICF. At this time, the ICR may be a control frame for confirming a TXOP or sequence or transmitting a response required by the ICF. Accordingly, the previously set basic NAV may be maintained as the OBSS AP or OBSS non-AP STAs transmit the ICR. Accordingly, the AP and non-AP STAs may identify the NPCA duration based on the basic NAV. At this time, the NPCA duration associated with the AP may be set to be shorter than the basic NAV by a switching delay (or switching latency). This is because the AP that has returned to the primary channel may need time (1260) to rejoin the contention after the OBSS is terminated. Additionally, the NPCA duration associated with non-AP STAs may be set to be shorter than the duration set for the basic NAV by the switching delay.This is because non-AP STAs may need time to switch from a secondary channel (e.g., S80) to a primary channel (e.g., P80). However, if non-AP STAs have an operating bandwidth of 80 MHz, the NPCA duration may require a larger switching delay (1255) than if the operating bandwidth is 160 MHz. This may be because the band where non-AP STAs perform NPCA is not the operating bandwidth (80 MHz) of non-AP STAs, so it may take more time for non-AP STAs to return to the primary channel after NPCA ends.

[0133] The AP can receive the preamble (1215) of the OBSS PPDU. In addition, the AP can set the duration of the NPC TXOP (1200) to the end of the OBSS PPDU through the preamble. In addition, the AP can perform EDCA contention on an anchor channel (1220). At this time, the anchor channel (1220) can be included in a non-primary channel (NPCH). The NPCH can mean all channels that can perform NPCA among secondary channels that do not overlap with OBSS transmission, and a 20 MHz channel that participates in contention for transmission among the NPCH can be the anchor channel. In addition, the AP can transmit a trigger frame (TF) (1225) to non-AP STAs. Accordingly, the non-AP STA(s) can transmit a response (1230) to the trigger frame to the AP. At this time, the AP can identify non-AP STA(s) to perform NPCA based on the response (1230). Accordingly, the AP can schedule downlink transmission including MU PPDU (1235) (e.g., NPCA MU PPDU) within NPC TXOP (1200) or schedule to receive uplink data from non-AP STA(s) based on the response (1230). In addition, the non-AP STA(s) can transmit a block Ack (blockACK) (1240) to the AP for transmission of the downlink data (1235) of the AP. Thereafter, multiple data exchanges (1245) between the AP and non-AP STA(s) can continue within the NPC TXOP (1200). Accordingly, the AP can also transmit a BA (1250) for uplink transmission of the non-AP STA(s) to the non-AP STA(s). Afterwards, there may be OBSS BA transmissions for OBSS PPDU transmissions on the primary channel (e.g., P80).And when the primary channel occupation of the OBSS BA ends, the AP and non-AP STA(s) return to the primary channel. In the above, the TXOP in which NPCA is performed is described as an NPC TXOP, but the TXOP described in the present disclosure below can be used with the same meaning as the NPC TXOP for performing NPCA.

[0134] Meanwhile, in order for the operations related to the above-described NPCA to be performed smoothly, the AP needs to obtain information about non-AP STAs that will perform NPCA (e.g., NPCA feedback information). For example, the NPCA feedback information may include information about the capability of non-AP STAs that will perform NPCA, information about the operating bandwidth of the non-AP STAs, information about the band (e.g., secondary channel) that will perform NPCA, information about the NPCA duration of the non-AP STAs, etc., and a more specific configuration is described in FIG. 15. The AP can perform scheduling for transmitting and / or receiving data within the NPC TXOP based on the NPCA feedback. Therefore, the following disclosure describes a method for transmitting NPCA feedback for scheduling in the NPC TXOP.

[0135] FIG. 13a illustrates an exemplary format of a multi-station block Ack (M-BA) frame in a wireless LAN system according to an embodiment of the present disclosure.

[0136] The M-BA frame illustrated in FIG. 13A may be a type of control frame. The M-BA frame may include at least one of a frame control field, a duration field, a receiving address (RA) field, a transmitter address (TA) field, a block ack control (BA) field, a BA information field (1310), or a frame check sequence (FCS) field. The BA information field may include a per AID TID information field (1320).<AID, TID> Each tuple can include. Each Per AID TID information field (1320) can include an AID TID information field (1330), a Block Ack starting sequence control field (1340), and a Block Ack bitmap field (1350).

[0137] The AID TID information field (1330) may include an AID11 field, an Ack Type field, and a TID field, and the fields included in the AID TID information field (1330) will be described in detail later in FIG. 14.

[0138] FIG. 13b is a diagram illustrating an example of fields included in an M-BA frame related to the present disclosure.

[0139] According to one embodiment, the value of a specific field included in the M-BA frame may be assigned as a value indicating NPCA feedback for TXOP. For example, a specific value among the values ​​indicated by the AID (association identifier) ​​field included in the M-BA frame may be assigned as a value indicating control extension. In addition, specific values ​​among the values ​​indicated by the Ack Type field and the TID field included in the M-BA frame may be assigned as values ​​indicating NPCA feedback. Meanwhile, the NPCA feedback is described above as being for TXOP, but is not limited thereto. Accordingly, the NPCA feedback may include information necessary during the NPCA operation, or may include information about a TXOP (e.g., NPC TXOP (1200)) that occurs during the NPCA operation. Hereinafter, NPCA feedback may be used with the same or similar meaning as described in FIG. 13b.

[0140] For example, any one of the values ​​indicated by the 11 bits included in the AID11 field of the M-BA frame may be assigned to indicate a control extension. As another example, any one of the combinations of the values ​​indicated by the 1 bit included in the Ack Type field of the M-BA frame and the values ​​indicated by the 4 bits included in the TID field may be assigned to indicate a control extension. Control extension may mean a case where a control frame is used for an extended purpose other than its original usage.

[0141] Specifically, any one of the reserved values ​​from 2008 to 2042 among the values ​​indicated by the AID11 field of the M-BA frame may be assigned to indicate the control extension of the M-BA frame. Alternatively, the AID11 field of the M-BA frame may also assign any one of the AID values ​​that may be assigned for the STA to indicate the control extension of the M-BA frame. For example, a specific value (e.g., 2006, etc.) among the values ​​that may be assigned as the AID of the STA may be utilized for the control extension of the M-BA frame. In addition, a combination of 0 or 1 among the values ​​of the Ack Type field of the M-BA frame and 8 to 13 among the values ​​of the TID field may be assigned to indicate NPCA feedback information among the control extensions. Any one of the reserved cases of the combination of the values ​​of the Ack Type field and the TID field may be utilized to indicate NPCA feedback for a TXOP, an example of which is illustrated in FIG. 13b (1360).

[0142] For example, if the AID11 field of the M-BA frame is assigned to 2008 (or 2009), the M-BA frame used for control extension can be broadcast. For example, if the AID11 field of the M-BA frame is assigned to 2008, non-AP STAs associated with the AP can receive the M-BA frame transmitted by the AP.

[0143] FIG. 14 is a diagram illustrating an exemplary format of a field included in a frame according to one embodiment of the present disclosure.

[0144] FIG. 14 illustrates an example of a format structure in which an M-BA frame includes an AID TID information field (1410), a Block Ack start sequence control field (1420), and a Block Ack bitmap field (1430). In addition, FIG. 14 illustrates an embodiment in which the AID TID information field (1410) includes an 11-bit AID11 field (1440), a 1-bit Ack Type field (1450), and a 4-bit TID field (1460), and the Block Ack start sequence control field (1420) includes a 4-bit fragment number field (1470) and a 12-bit starting sequence number field (1480).

[0145] Hereinafter, an embodiment proposed in the present disclosure will be described in more detail based on the format structure and fields of the frame illustrated in FIG. 14. In one embodiment, a non-AP STA may transmit an M-BA frame to an AP, and the M-BA frame may be a frame for notifying or feeding back information related to a secondary channel for NPCA (hereinafter, referred to as NPCA feedback information) within a TXOP. According to an example, the M-BA frame transmitted by the non-AP STA may include an ICR, which is a response to an ICF, within the TXOP. In this case, the M-BA frame may also include additional control feedback information (e.g., NPCA feedback information) according to the proposed embodiment. As another example, an M-BA frame transmitted by a non-AP STA may include an acknowledgment for a PPDU within a TXOP, and in such a case, the M-BA frame may include not only the acknowledgment for the PPDU but also information about an NPCA due to an OBSS in case an unexpected OBSS suddenly occurs in a non-AP STA operating within the TXOP.

[0146] According to one embodiment, the AID11 field (1440) of the M-BA frame that the non-AP STA transmits to the AP to indicate NPCA feedback information for the TXOP may include a predetermined value (e.g., 2009 or any other reserved values) to indicate a control extension. Alternatively, the AID11 field (1440) of the M-BA frame that the non-AP STA transmits to the AP to indicate NPCA feedback information for the TXOP may include the AID of the non-AP STA or the AID of the AP. Alternatively, the value of the AID11 field (1440) of the M-BA frame that the non-AP STA transmits to the AP to indicate NPCA feedback information for the TXOP may include 0. The combination of the value of the Ack Type field (1450) and the value of the TID field (1460) may include values ​​for indicating NPCA feedback information (for example, the value of the Ack Type field may include 0 or 1, and the value of the TID field may include 8 or one of the reserved values ​​8 to 13).

[0147] According to one embodiment, the fragment number field (1470) of the Block Ack start sequence control field (1420) may indicate the size of the Block Ack bitmap field (1430), and the start sequence number field (1480) of the Block Ack start sequence control field (1420) may include AID12 or AID11 of a non-AP STA transmitting an M-BA frame to indicate NPCA feedback information. Alternatively, the start sequence number field (1480) of the Block Ack start sequence control field (1420) may include AID12 or AID11 of an AP or non-AP STA receiving an M-BA frame instead of AID12 or AID11 of an STA transmitting an M-BA frame.

[0148] According to one embodiment, the Block Ack bitmap field (1430) includes actual information transmitted for control extension. For example, when an M-BA frame is transmitted to indicate NPCA feedback information, the Block Ack bitmap field (1430) may include specific information about a secondary channel (or non-primary channel (NPCH)) for NPCA. For example, the Block Ack bitmap field (1430) may include an NPCA feedback information field (or NPCH information field). Meanwhile, in the present disclosure, a secondary channel may include consecutive channels excluding a primary channel. In addition, a secondary channel may include a non-primary channel (NPCH), and the NPCH may mean all channels capable of performing NPCA among secondary channels that do not overlap with OBSS transmission. For example, a secondary channel of 60MHz may include a secondary 20MHz and a secondary 40MHz, but the NPCH may be set to either the secondary 20MHz or the secondary 40MHz.

[0149] The above describes an embodiment in which a non-AP STA transmits an M-BA frame to inform the AP of NPCA feedback information for a TXOP. Conversely, an AP may also transmit an M-BA frame to inform a non-AP STA of NPCA feedback information for a TXOP. If an AP transmits an M-BA frame to inform NPCA feedback information, the explanation previously given for a non-AP STA may be applied identically or similarly to the AP.

[0150] FIG. 15 illustrates a format including NPCA feedback information in a wireless LAN system according to an embodiment of the present disclosure.

[0151] Figure 15 specifically describes the NPCA feedback information described above. Figure 15 illustrates an exemplary format structure of the NPCA feedback information field described above.

[0152] In one embodiment, the NPCA feedback information field may include at least one of a presence field (1510), a time unit field (1515), a BasicNAV field (1520), an NPCA duration (NPCADuration) field (1525), an NPCH field (1530), an OBSS Info field (1535), an NPCH Channel Info field (1540), or an NPCA continuation field (1545), and some of the bits included in the NPCA feedback information field may be reserved. In addition, since the NPCH channel information field may include information of different sizes for each non-AP STA transmitting the M-BA, the size of the NPCA feedback information field may not be fixed. Additionally, either the basic NAV field (1520) or the NPCA duration field (1525) described above may be omitted, and the NPCA feedback information field may not necessarily include both fields.

[0153] The presence field (1510) may indicate which fields are included in the NPCA feedback information field and which subfields are included in the field. Meanwhile, the subfields included in the NPCA feedback information field may vary depending on whether the subject of the feedback is an AP or a non-AP STA.

[0154] The time unit (1515) field can indicate the unit indicated by the values ​​indicated by the basic NAV field (1520) and the NPCA duration field (1525). For example, if the value of the time unit field (1515) is 0, 1, ..., 7, it can indicate that the units of the values ​​indicated by the basic NAV field (1520) and the NPCA duration field (1525) are 1 μs, 2 μs, ..., 128 μs, respectively. Alternatively, the time unit field (1515) may also include a bitmap for indicating a unit of power of 2.

[0155] The Basic NAV field (1520) may indicate the length of the time interval of the Basic NAV. For example, the Basic NAV field (1520) may indicate the length of the time interval from the time when the ICF transmission is completed (or the time when the Basic NAV is set based on the ICF-ICR) to the time when the OBSS is terminated (e.g., the time when the OBSS BA transmission is completed).

[0156] The NPCA duration field (1525) may indicate the length of the time interval during which the NPCA continues. In addition, the NPCA duration field (1525) may indicate a time interval considering the NPCA duration and switching delay.

[0157] The NPCH field (1530) may indicate the bandwidth over which NPCA, including the anchor channel, will operate. For example, the NPCH field (1530) may include a bitmap or encoded value to indicate the usage (or bandwidth) of a secondary channel that can be used by an AP or non-AP STA. In this case, the NPCH field (1530) may refer to all channels capable of performing NPCA among secondary channels that do not overlap with OBSS transmissions.

[0158] The OBSS information field (1535) may include information about the OBSS that triggers the NPCA. For example, the information about the OBSS may include at least one of an OBSS transmission type, an OBSS BSS color, or an OBSS transmission bandwidth. The OBSS transmission type may include information about at least one of an OBSS TXOP or an OBSS HE (high efficiency) / EHT (extreme high throughput) / UHR (ultra-high reliability) PPDU. Accordingly, when the OBSS transmission type is received, it may be possible to identify whether the NPCA is based on the OBSS TXOP or is initiated by receiving a HE / EHT / UHR PPDU. The OBSS color may be information for quickly determining whether the received PPDU is a transmission of the OBSS based on information included in the preamble of the OBSS packet identified by the non-AP STA. The OBSS transmission bandwidth may include information about the bandwidth used by the OBSS data identified by the non-AP STA. Therefore, the OBSS transmission bandwidth may contain different information from the NPCH, which is information about the bandwidth to be used by the non-AP STA for NPCA operation.

[0159] The NPCH channel information (or NPCH information) field (1540) may include information about the status of the NPCH, which is a channel to be used for NPCA operation. For example, the information about the NPCH may include at least one of the received signal strength (e.g., received signal strength (RSS) or RSS indicator (RSSI)) of an ICF (e.g., a BSRP trigger frame that initiates a TXOP), channel sounding feedback measured by the ICF, a preferred modulation and coding scheme (MCS) index of subsequent uplink / downlink transmission, or a preferred number of spatial streams (NSS) for subsequent uplink / downlink transmission. An AP may schedule a non-AP STA based on the NPCH channel information field (1545). For example, a non-AP STA may determine an uplink transmission parameter based on the NPCH channel information field (1545). Meanwhile, if the subject of NPCA feedback is an AP rather than a non-AP STA, the NPCH channel information field (1545) may be omitted.

[0160] The NPCA continuation field (1545) may indicate whether a non-AP STA has additional (subsequent) NPCA transmissions. For example, a non-AP STA may set NPCA continuation to 0 to terminate NPCA. In this case, if the subject of the NPCA feedback is an AP rather than a non-AP STA, setting NPCA continuation to 0 may indicate that all NPCAs for at least one non-AP STA are terminated.

[0161] The above describes an exemplary format of the NPCA feedback information field. However, the Block Ack bitmap field including information for indicating the NPCA feedback information may be configured to include fewer or more fields than the structure illustrated. For example, the Block Ack bitmap field may include fewer or equal number of bits than 64 bits, in which case the NPCA feedback information field of the Block Ack bitmap field may be configured to include only some fields among the illustrated embodiments while omitting some fields. When the Block Ack bitmap field includes only some of the fields according to the illustrated embodiments, whether or not the NPCA feedback information field includes some fields / subfields may be indicated by the presence field (1510) described above.

[0162] Meanwhile, according to the embodiments described above, a non-AP STA may transmit an M-BA frame to an AP to indicate NPCA feedback information for a TXOP. Conversely, an AP may also transmit an M-BA frame to a non-AP STA to indicate NPCA feedback information for a TXOP. In addition, a non-AP STA and an AP may transmit an M-BA frame to indicate NPCA feedback information even in a single-STA single-TID situation, and in particular, an M-BA frame to indicate NPCA feedback information may be used as a response to an aggregated MAC PDU (A-MPDU) transmission in a single-STA single-TID and for control extension. In addition, a non-AP STA or an AP may transmit an M-BA frame to indicate NPCA feedback information in response to a trigger frame transmitted from an AP or a non-AP STA. That is, an AP or non-AP STA can transmit an M-BA frame to indicate NPCA feedback information as a response to a trigger frame even if it does not receive data.

[0163] According to the proposed embodiments, a non-AP STA can report or inform the AP of NPCA feedback information within a TXOP initiated by the AP (or mobile AP). Furthermore, the AP (or mobile AP) can inform its associated STAs (i.e., non-AP STAs) of the NPCA feedback information within the TXOP initiated by the AP (or mobile AP). Furthermore, the AP (or mobile AP) can inform the non-AP STA of the NPCA feedback information within the TXOP initiated by the non-AP STA.

[0164] The above-described embodiments focus on the case where a TXOP is initiated based on a trigger frame transmitted by the AP, but are not limited thereto. Accordingly, if a non-AP STA initiates a TXOP for uplink transmission via an ICF, the AP may also transmit an M-BA as an ICR, and the above-described examples may be applied in the same manner.

[0165] Additionally, although the above-described embodiment exemplifies a case where the M-BA includes NPCA feedback information, it may further include an acknowledgment to a transmission from an AP (or non-AP STA).

[0166] FIG. 16 illustrates a method for transmitting NPCA feedback information using a multi-TID (traffic identifier) ​​block Ack in a wireless LAN system according to an embodiment of the present disclosure.

[0167] An embodiment in which a device transmits or receives an M-BA frame to indicate NPCA feedback information for a TXOP has been described above. FIG. 16 illustrates an embodiment in which a device (non-AP STA or AP) transmits or receives a multi-TID block ack frame to indicate NPCA feedback information for a TXOP.

[0168] Fig. 16 illustrates an exemplary format structure of a multi-TID block ack frame. According to an embodiment, the multi-TID block ack frame may include a Per TID information field (1610), a Block Ack starting sequence control field (1620), and a Block Ack bitmap field (1630), and the Per TID information field (1610), the Block Ack starting sequence control field (1620), and the Block Ack bitmap field (1630) may be repeated for each TID within the multi-TID block ack.

[0169] According to one embodiment, the Per TID information field (1610) may include a TID value field (1640) and reserved bits, and the Block Ack start sequence control field (1620) may include a fragment number field (1650) and a start sequence number field (1660). In one embodiment, the size of the Block Ack bitmap field (1630) may be fixed to 8 octets, and the fragment number field (1650), which indicates the size of the Block Ack bitmap field (1630), may indicate a fixed value of 0.

[0170] Hereinafter, an embodiment proposed in the present disclosure will be described in more detail based on the format structure and fields of the frame illustrated in FIG. 16. In one embodiment, a non-AP STA may transmit a multi-TID block ack frame to an AP, and the multi-TID block ack frame may be a frame for notifying NPCA feedback information within a TXOP. The multi-TID block ack frame transmitted by the non-AP STA may include an acknowledgment for a PPDU, and may further include information for indicating a control extension related to the NPCA feedback information for the TXOP.

[0171] According to one embodiment, in a multi-TID block ack frame that a non-AP STA transmits to an AP to indicate NPCA feedback information for a TXOP, 11 bits (e.g., B0 - B10) or 12 bits (e.g., B0 - B11) of the 12 reserved bits (B0 - B11) included in the per TID information field (1610) may be used to indicate a control extension, and examples of specific values ​​may be similarly applied to the embodiment described in the AID11 field (1440) described above in FIG. 14.

[0172] According to another embodiment, in a multi-TID block ack frame that a non-AP STA transmits to an AP to indicate NPCA feedback information for a TXOP, a combination of a value of one bit (e.g., B11) among 12 reserved bits (B0 to B11) included in a per TID information field (1610) and a value of a TID value field (1640) may include values ​​for indicating NPCA feedback information. A specific example of a combination of a value of one reserved bit and a value of a TID value field (1640) may be similarly applied to the embodiment described in the Ack Type field (1450) and the TID field (1460) described above in FIG. 14, and the value of the TID value field (1640) may be any one of reserved 8 to 15.

[0173] In another embodiment, any one of the reserved values ​​of the TID value field (1640) in the multi-TID block ack frame that the non-AP STA transmits to the AP to indicate NPCA feedback information for the TXOP may indicate the NPCA feedback information. For example, any one of the reserved values ​​8 to 15 of the TID value field (1640) may indicate the NPCA feedback information.

[0174] In one embodiment, the start sequence number field (1660) included in the Block Ack start sequence control field (1620) may include AID11 or AID12 of a non-AP STA transmitting a multi-TID block ack frame. Alternatively, the start sequence number field (1680) of the Block Ack start sequence control field (1620) may include AID12 or AID11 of an AP or non-AP STA receiving an M-BA frame instead of AID12 or AID11 of an STA transmitting an M-BA frame. The Block Ack bitmap field (1630) includes actual information transmitted for control extension and may have a fixed size of 8 octets. For example, the Block Ack bitmap field (1630) may include at least some of the various fields / subfields included in the Block Ack bitmap field (1430) described in FIG. 14 and the NPCA feedback information field described in FIG. 15, and at least some may be omitted. For example, the Block Ack bitmap field (1630) of the multi-TID block ack frame may be configured to include only some of the NPCA feedback information fields described in FIG. 15.

[0175] The above describes an embodiment in which a non-AP STA transmits a multi-TID block ack frame to inform the AP of NPCA feedback information for a TXOP. Conversely, the AP may also transmit a multi-TID block ack frame to inform the non-AP STA of NPCA feedback information for a TXOP. If the AP transmits a multi-TID block ack frame to inform the non-AP STA of NPCA feedback information, the explanation previously given for the non-AP STA may be applied identically or similarly to the AP.

[0176] FIG. 17 illustrates a method for transmitting NPCA feedback information using M-BA in a wireless LAN system according to an embodiment of the present disclosure.

[0177] Referring to FIG. 17, specific operations of an NPCA AP and a non-AP STA for transmitting and receiving data via NPCA are described in chronological order. For example, below, an NPCA AP may have an operating bandwidth of 160 MHz (e.g., including P80 and S80), and NPCA non-AP STA(s) may have an operating bandwidth of 80 MHz or 160 MHz. In addition, below, an NPCA AP may refer to an AP capable of performing NPCA or an AP performing NPCA. An NPCA non-AP STA or NPCA STA may refer to an STA capable of performing NPCA or an STA performing NPCA. In addition, below, an NPCA AP and an NPCA STA may also be referred to as an AP and a non-AP STA (or STA), respectively. In addition, the method of transmitting NPCA feedback information using M-BA below may include a description overlapping with the description described in FIG. 12 described above, and the overlapping description may be omitted.

[0178] In one embodiment, non-AP STAs may participate in contention and attempt to access the primary channel (e.g., P80). Non-AP STAs (e.g., NPCA STAs) or APs (e.g., NPCA APs) may receive (or detect) an ICF (e.g., OBSS ICF (1705)) from an OBSS AP or OBSS STA during the process of participating in contention on the primary channel 80 MHz (P80). A basic NAV may be set based on the ICF. In addition, the OBSS non-AP STA or OBSS AP that received the ICF may transmit an ICR (e.g., OBSS ICR (1710)) to the OBSS AP or OBSS non-AP in response to the ICF. Therefore, when OBSS APs or OBSS non-AP STAs transmit ICRs, the previously set basic NAV can be maintained, and the APs and non-AP STAs can identify the NPCA duration based on the basic NAV. At this time, the NPCA duration related to the AP can be set to be shorter by the switching delay (or switching latency) than the period set as the basic NAV. This is because the AP that has returned to the primary channel may need time (1760) to rejoin the contention after the OBSS is terminated. In addition, the NPCA duration related to non-AP STAs can be set to be shorter by the switching delay than the period set as the basic NAV. This is because the non-AP STAs may need time to switch from the secondary channel (e.g., S80) to the primary channel (e.g., P80). However, if non-AP STAs have an operating bandwidth of 80 MHz, the NPCA duration may require a larger switching delay (1755) than for an operating bandwidth of 160 MHz.This may be because the band where non-AP STAs perform NPCA is not the operating bandwidth (80MHz) of non-AP STAs, so it may take more time for non-AP STAs to return to the primary channel after NPCA is terminated. In addition, the AP can receive the preamble (1715) of the OBSS PPDU. In addition, the AP can set the duration of the NPC TXOP (1700) until the end of the OBSS PPDU through the preamble.

[0179] The AP can perform EDCA contention on an anchor channel (1720). At this time, the anchor channel (1720) can be included in the NPCH. In addition, the AP can transmit a trigger frame (TF) (1725) to non-AP STAs. At this time, the trigger frame can include at least one of a buffer status report poll (BSRP) trigger frame, a bandwidth query report poll (BQRP) trigger frame, a basic trigger frame, or a multi-user block ack request (MU-BAR) trigger frame. Accordingly, the non-AP STA(s) can transmit an M-BA frame (1730) to the AP in response to the trigger frame. At this time, the M-BA frame (1730) can include at least some of the formats included in the M-BA frame illustrated in FIG. 14. In addition, the NPCA feedback information included in the M-BA frame (1730) may include at least some of the subfields of the NPCA feedback information illustrated in FIG. 15. The AP may obtain NPCA feedback information for a TXOP based on the M-BA frame (1730). In addition, the AP may identify information required for an NPCA operation or information on a TXOP (e.g., NPC TXOP (1700)) generated during the NPCA operation based on the NPCA feedback information. Accordingly, the AP may schedule downlink transmission including downlink data (1735) (e.g., DL MU PPDU) within the NPC TXOP (1700) based on the information of the secondary channel, or schedule reception of uplink data from non-AP STA(s).

[0180] Additionally, non-AP STA(s) may transmit a response frame (e.g., M-BA frame) (1740) to the AP for the downlink transmission (1735). At this time, the response frame may further include NPCA feedback information in addition to an acknowledgement for the downlink transmission (1735). Thereafter, multiple data exchanges (1745) between the AP and non-AP STA(s) may continue within the NPC TXOP (1700). Accordingly, the AP may transmit an M-BA frame (1750) for the uplink transmission of the non-AP STA(s) to the non-AP STA(s). At this time, the M-BA frame (1750) may include a response to the uplink transmission of the non-AP STA(s) and / or information of the NPCH related to the downlink transmission transmitted by the AP. Afterwards, there may be OBSS BA transmission according to OBSS PPDU transmission on the primary channel (e.g., P80). And when the primary channel occupation of OBSS BA ends, the AP and non-AP STA(s) return to the primary channel. In the above, the TXOP in which NPCA is performed is described as NPC TXOP, but the TXOP described in the present disclosure below can be used with the same meaning as the NPC TXOP for performing NPCA.

[0181] The M-BA frame described in FIG. 17 may include the M-BA frames described in FIGS. 13a, 13b, 14, and 15. In addition, in FIG. 17, the AP and non-AP STA(s) may transmit response and / or NPCA feedback information using the multi-TID block ack frame described in FIG. 16 instead of the M-BA frame. Accordingly, the embodiments of the present disclosure described above may be applied identically or similarly to FIG. 17.

[0182] Meanwhile, if a non-AP STA only receives a CTS, it may be difficult to perform NPCA operation. If a non-AP STA only receives a CTS without first receiving an RTS, it may be difficult to identify whether the CTS is sent by an AP destined for a non-AP STA within the same BSS or a CTS destined for an OBSS AP or an OBSS non-AP within an OBSS. This may be because the CTS only includes a destination address (RA). Furthermore, it may be difficult for the AP or non-AP STA to know the bandwidth secured by the received CTS. Therefore, the following describes a method for an AP that receives an M-BA frame or a multi-TID block Ack frame to identify whether the BSS is an OBSS and obtain transmission bandwidth information based on the information about the BSS by including information about the BSS in a response (e.g., an acknowledgment for an ICR or PPDU) through an M-BA frame or a multi-TID block Ack frame.

[0183] FIG. 18 is a diagram illustrating an exemplary format of a field included in a frame according to one embodiment of the present disclosure.

[0184] Referring to FIG. 18, a method for a non-AP STA (or AP) to transmit BSS information for identifying an OBSS using an M-BA frame is described. Meanwhile, the method for transmitting BSS using an M-BA frame, described below, can use the same control frame as the method for transmitting NPCA feedback information using an M-BA frame, described above. Therefore, the description of the control frame (e.g., an M-BA frame) described above can also be applied below.

[0185] In one embodiment, the M-BA frame illustrates an example of a format structure including an AID TID information field (1810), a Block Ack start sequence control field (1820), and a Block Ack bitmap field (1830). In addition, FIG. 18 illustrates an embodiment in which the AID TID information field (1810) includes an 11-bit AID11 field (1840), a 1-bit Ack Type field (1850), and a 4-bit TID field (1860), and the Block Ack start sequence control field (1820) includes a 4-bit fragment number field (1870) and a 12-bit start sequence number field (1880).

[0186] In one embodiment, a non-AP STA may transmit an M-BA frame to the AP, and the M-BA frame may be a frame for notifying or feeding back information related to a BSS for identifying an OBSS (hereinafter, referred to as BSS information). According to one example, the M-BA frame transmitted by the non-AP STA may include an ICR, which is a response to an ICF, within the TXOP. In this case, the M-BA frame may also include additional control feedback information (e.g., BSS information) according to the proposed embodiment. According to another example, the M-BA frame transmitted by the non-AP STA may include an acknowledgment for a PPDU within the TXOP, and in this case, the M-BA frame may include not only the acknowledgment for the PPDU, but also BSS information related to the OBSS when an unexpected OBSS suddenly occurs in a non-AP STA operating within the TXOP.

[0187] According to one embodiment, the AID11 field (1840) of the M-BA frame that a non-AP STA transmits to an AP to indicate BSS information for an OBSS may include a predetermined value (e.g., 2010 or any one of other reserved values) for indicating control extension. Alternatively, the AID11 field (1840) of the M-BA frame that a non-AP STA transmits to an AP to indicate BSS information for an OBSS may include an AID of the non-AP STA or an AID of the AP, and a combination of a value of the Ack Type field (1850) and a value of the TID field (1860) may include values ​​for indicating BSS information (e.g., the value of the Ack Type field may include 0 or 1, and the value of the TID field may include 8 or any one of the reserved values ​​8 to 13).

[0188] According to one embodiment, the fragment number field (1870) of the Block Ack start sequence control field (1820) may indicate the size of the Block Ack bitmap field (1830), and the start sequence number field (1880) of the Block Ack start sequence control field (1820) may include AID12 or AID11 of a non-AP STA transmitting an M-BA frame to indicate BSS information. Alternatively, the start sequence number field (1880) of the Block Ack start sequence control field (1820) may include AID12 or AID11 of an AP or non-AP STA receiving an M-BA frame instead of AID12 or AID11 of an STA transmitting an M-BA frame.

[0189] According to one embodiment, the Block Ack bitmap field (1830) includes actual information transmitted for control extension. For example, if the M-BA frame is transmitted to indicate BSS information, the Block Ack bitmap field (1830) may include specific information about the BSS for identifying the OBSS. For example, the Block Ack bitmap field (1830) may include a BSS information field.

[0190] FIG. 19 illustrates a format including BSS information in a wireless LAN system according to an embodiment of the present disclosure.

[0191] Figure 19 specifically describes the BSS information described above. Figure 19 illustrates an exemplary format structure of the BSS information field described above.

[0192] In one embodiment, the BSS information field may include at least one of a presence field (1910), a BSS ID (BSSID) field (1920), a BSS color field (1930), a transmit bandwidth field (1940), or a primary channel field (1950), and some of the bits included in the BSS information field may be reserved. In addition, since the BSS information field may include information of different sizes, the size of the BSS information field may not be fixed.

[0193] The presence field (1910) can indicate which fields are included in which subfields in the BSS information field.

[0194] The BSS ID field (1920) may indicate the ID of the BSS to which the AP or non-AP STA belongs (e.g., the MAC address of the AP) and may have a size of 48 bits.

[0195] The BSS color field (1930) can indicate the color of the BSS to which the AP or non-AP STA belongs, and can have a size of 4 bits.

[0196] The transmission bandwidth field (1940) can indicate the maximum amount of bandwidth to be used within the TXOP and can have a size of 4 bits.

[0197] The primary channel field (1950) may indicate the number of the primary channel to which the AP or non-AP STA belongs, and may have a size of 8 bits.

[0198] The exemplary format of the BSS information field has been described above. However, the Block Ack bitmap field, which includes information for indicating BSS information, may be configured to include fewer or more fields than the structure illustrated. For example, the Block Ack bitmap field may include fewer or equal number of bits than 128 bits, in which case the BSS information field of the Block Ack bitmap field may be configured to include only some fields while omitting some of the fields according to the illustrated embodiment. When the Block Ack bitmap field includes only some of the fields according to the illustrated embodiment, whether or not the BSS information field includes any fields / subfields may be indicated by the presence field (1910) described above.

[0199] According to the proposed embodiments, a non-AP STA or AP (or mobile AP) can transmit an M-BA frame including BSS information as an ICR, and an AP receiving the M-BA frame can identify, based on the BSS information, whether the non-AP STA or AP (or mobile AP) that transmitted the BSS information corresponds to an OBSS occupying a primary channel.

[0200] Meanwhile, FIG. 16 describes an embodiment in which a device (non-AP STA or AP) transmits or receives a multi-TID block ack frame to indicate NPCA feedback information for a TXOP. The BSS information described in FIG. 19 may also be included in the multi-TID block ack frame described in FIG. 16. In this case, the format structure of the multi-TID block ack frame may be configured in the same manner as the format structure of the multi-TID block ack frame of FIG. 16 described above.

[0201] According to one embodiment, in a multi-TID block ack frame including BSS information, 11 bits (e.g., B0 - B10) or 12 bits (e.g., B0 - B11) out of 12 reserved bits (B0 - B11) included in the per TID information field may be used to indicate control extension, and examples of specific values ​​may be similarly applied to the embodiment described in the AID11 field (1440) described in FIG. 14 above.

[0202] According to another embodiment, in a multi-TID block ack frame that a non-AP STA transmits to an AP to indicate BSS information, a combination of a value of one bit (e.g., B11) among 12 reserved bits (B0 to B11) included in a per TID information field and a value of a TID value field may include values ​​for indicating BSS information. A specific example of a combination of a value of one reserved bit and a value of a TID value field may be similarly applied to the embodiment described in the Ack Type field (1450) and the TID field (1460) described above in FIG. 14, and the value of the TID value field may be any one of reserved 8 to 15.

[0203] In another embodiment, any one of the reserved values ​​of the TID value field in a multi-TID block ack frame containing BSS information may indicate BSS information. For example, any one of the reserved values ​​8 to 15 of the TID value field may indicate BSS information.

[0204] In one embodiment, the start sequence number field included in the Block Ack start sequence control field may include AID11 or AID12 of a non-AP STA transmitting a multi-TID block ack frame. The Block Ack bitmap field may include actual information (e.g., BSS information) transmitted for control extension and may have a fixed size of 8 octets. The fragment number field indicating the size of the Block Ack bitmap field may indicate a fixed value of 0.

[0205] FIG. 20 illustrates a method for transmitting BSS information using M-BA in a wireless LAN system according to an embodiment of the present disclosure.

[0206] Referring to FIG. 20, specific operations of an NPCA AP and an NPCA STA for identifying an OBSS based on BSS information included in an ICR and transmitting and receiving data through NPCA are described in chronological order. For example, below, an NPCA AP may have an operating bandwidth of 160 MHz (e.g., including P80 and S80), and NPCA STA(s) may have an operating bandwidth of 80 MHz or 160 MHz. In addition, below, an NPCA AP may mean an AP capable of performing NPCA or an AP performing NPCA. An NPCA non-AP STA or NPCA STA may mean an STA capable of performing NPCA or an STA performing NPCA. In addition, below, an NPCA AP and an NPCA STA may also be referred to as an AP and a non-AP STA, respectively. Additionally, if an OBSS is identified based on the BSS information below, the subsequent NPCA operation may include a description overlapping with the previously described Fig. 17, and the overlapping description may be omitted.

[0207] In one embodiment, non-AP STAs may participate in contention and attempt to access the primary channel (e.g., P80). However, the AP may detect an ICR of an OBSS (e.g., an ICR transmitted by an OBSS AP or OBSS STA). At this time, the ICR (e.g., an M-BA or multi-TID block ack) may include BSS information related to the OBSS. In addition, since S80 is idle for TXOP, the AP may perform NPCA. At this time, the BSS information included in the ICR may include the BSS information of FIG. 19 described above. Meanwhile, a non-AP STA may also attempt to access the channel, but may detect an ICR of an OBSS (e.g., an ICR transmitted by an OBSS AP or OBSS STA). At this time, the ICR (e.g., an M-BA or multi-TID block ack) may include BSS information related to the OBSS. Additionally, non-AP STAs can perform NPCA since the secondary channel (e.g., S80) is idle for TXOP. Accordingly, the operations performed when performing NPCA are described below, and the following NPCA operations may overlap with the NPCA operations described above in FIG. 17. Of course, if the BSS information in the above example indicates that it is not an OBSS, the AP and non-AP STAs may not perform the following NPCA operations.

[0208] The NPCA duration of an AP may be set to be shorter than the period set as the basic NAV. This is because an AP that has returned to the primary channel may need time (2050) to rejoin contention after the OBSS ends. In addition, the NPCA duration of non-AP STAs may be set to be shorter than the period set as the basic NAV by the switching delay. This is because non-AP STAs may need time to switch from a secondary channel (e.g., S80) to a primary channel (e.g., P80). However, if non-AP STAs have an operating bandwidth of 80 MHz, the NPCA duration may require a larger switching delay (2045) than if they have an operating bandwidth of 160 MHz. This may be because the band where non-AP STAs perform NPCA is not the operating bandwidth of non-AP STAs (80 MHz), and therefore, non-AP STAs may need more time to return to the primary channel after the NPCA ends. The AP can perform EDCA contention on the anchor channel (2010). At this time, the anchor channel (2010) can be included in the NPCH. And the AP can transmit a trigger frame (TF) (2015) to non-AP STAs. At this time, the trigger frame can include at least one of a BSRP trigger frame, a BQRP trigger frame, a basic trigger frame, or a MU-BAR trigger frame. Accordingly, the non-AP STA(s) can transmit an M-BA frame (2020) to the AP in response to the trigger frame. At this time, the M-BA frame (2020) can include at least some of the formats included in the M-BA frame illustrated in FIG. 14. In addition, the NPCA feedback information included in the M-BA frame (2020) can include at least some of the subfields of the NPCA feedback information illustrated in FIG. 15. The AP can obtain NPCA feedback information for TXOP based on the M-BA frame (2020).Additionally, the AP can identify information required for NPCA operation or information about TXOP (e.g., NPC TXOP (2000)) occurring during NPCA operation based on NPCA feedback information. Accordingly, the AP can schedule downlink transmission including downlink data (2025) (e.g., NPCA MU PPDU) within the NPC TXOP (2000) or schedule reception of uplink data from non-AP STA(s) based on information of the secondary channel.

[0209] In addition, non-AP STA(s) may transmit a response frame (e.g., M-BA frame) (2030) to the AP for the downlink transmission (2025). At this time, the response frame may further include, for example, NPCA feedback information in addition to an acknowledgement for the downlink transmission (2025). Thereafter, multiple data exchanges (2035) between the AP and non-AP STA(s) may continue within the NPC TXOP (2000). Accordingly, the AP may transmit an M-BA frame (2040) for the uplink transmission of the non-AP STA(s) to the non-AP STA(s). At this time, the M-BA frame (2040) may include a response to the uplink transmission of the non-AP STA(s) and / or information of the NPCH related to the downlink transmission transmitted by the AP.

[0210] The M-BA frame including the BSS information described in FIG. 20 may include the M-BA frame described in FIG. 18. Furthermore, instead of the M-BA frame in FIG. 20, the BSS information may be included in the multi-TID block ack frame described in FIG. 19. Accordingly, the embodiments of the present disclosure described above may be applied identically or similarly to FIG. 20.

[0211] FIG. 21 illustrates a flowchart of operations for transmitting NPCA feedback information in a wireless LAN system according to one embodiment of the present disclosure.

[0212] Referring to FIG. 21, the NPCA operation proposed in the present disclosure is illustrated, and some or all of the various embodiments related to non-AP STAs (e.g., NPCA STAs) described above may be applied identically or similarly to FIG. 21.

[0213] At step 2110, the non-AP STA may receive a first frame from the AP to initiate a TXOP on a secondary channel. For example, the secondary channel may be an available continuous channel excluding the primary channel occupied by the OBSS. Accordingly, the TXOP may be initiated with the transmission of a first frame to trigger NPCA. In addition, the first frame may include a trigger frame for initiating the TXOP, and the trigger frame may include a BSRP trigger frame, a BQRP trigger frame, a basic trigger frame, or an MU-BAR trigger frame.

[0214] At step 2120, the non-AP STA may transmit a second frame to the AP containing feedback information for NPCA in response to a TXOP. For example, the feedback information for NPCA may include at least one parameter related to the NPCH. Additionally, the second frame may include an M-BA frame or a multi-TID block ack frame.

[0215] At step 2130, the non-AP STA may transmit and / or receive data (e.g., MU PPDU) to and from the AP based on scheduling based on feedback information regarding the NPCA. For example, the AP may schedule downlink transmission and / or uplink transmission based on feedback information regarding the NPCA transmitted by the non-AP STA.

[0216] Meanwhile, in the above, one embodiment of the operation of a non-AP STA and an AP has been described based on the flow chart illustrated in FIG. 21, but it is obvious that the operation of a non-AP STA and an AP may vary depending on other embodiments described above.

[0217] FIG. 22 illustrates a flowchart of operations for transmitting NPCA feedback information in a wireless LAN system according to one embodiment of the present disclosure.

[0218] Referring to FIG. 22, the NPCA operation proposed in the present disclosure is illustrated, and some or all of the various embodiments related to the AP (e.g., NPCA AP) described above may be applied identically or similarly to FIG. 21.

[0219] At step 2210, the AP may transmit a first frame to initiate a TXOP on a secondary channel to a non-AP STA. For example, the secondary channel may be an available continuous channel excluding the primary channel occupied by the OBSS. Accordingly, the AP may initiate the TXOP by transmitting the first frame to trigger NPCA. Furthermore, the first frame may include a trigger frame for initiating the TXOP, and the trigger frame may include a BSRP trigger frame, a BQRP trigger frame, a basic trigger frame, or an MU-BAR trigger frame.

[0220] At step 2220, the AP may receive a second frame from a non-AP STA containing feedback information for NPCA for a TXOP. For example, the feedback information for NPCA may include at least one parameter related to the NPCH. Additionally, the second frame may include an M-BA frame or a multi-TID block ack frame.

[0221] At step 2230, the AP may transmit and / or receive data (e.g., MU PPDU) to and from non-AP STAs based on scheduling based on feedback information for NPCA. For example, an AP that has received feedback information for NPCA from a non-AP STA may schedule downlink transmission and / or uplink transmission with the non-AP STA based on the feedback information.

[0222] Meanwhile, in the above, one embodiment of the operation of a non-AP STA and an AP has been described based on the flow chart illustrated in FIG. 22, but it is obvious that the operation of a non-AP STA and an AP may vary depending on other embodiments described above.

[0223] FIG. 23 illustrates a flowchart of operations for transmitting BSS information in a wireless LAN system according to an embodiment of the present disclosure.

[0224] Referring to FIG. 23, an operation for obtaining BSS information for identifying an OBSS based on BSS information proposed in the present disclosure is illustrated, and some or all of the various embodiments related to a non-AP STA (e.g., NPCA STA) or AP (e.g., NPCA AP) described above may be applied identically or similarly to FIG. 23.

[0225] In step 2310, a non-AP STA or AP may search for an ICR containing parameters related to a BSS for identifying an OBSS. For example, the ICR may include an M-BA frame or a multi-TID block ack frame.

[0226] At step 2320, if an OBSS is identified based on parameters associated with the acquired BSS, the non-AP STA and AP may perform NPCA. For example, if the discovered ICR is identified as an OBSS based on parameters associated with the BSS, the non-AP STA and AP may perform NPCA according to the operations described in this disclosure.

[0227] Meanwhile, in the above, one embodiment of the operation of a non-AP STA and an AP has been described based on the flowchart illustrated in FIG. 23, but it is obvious that the operation of a non-AP STA and an AP may vary depending on other embodiments described above.

[0228] Meanwhile, the present specification and drawings disclose preferred embodiments of the present disclosure, and although specific terms are used, they are used only in a general sense to easily explain the technical contents of the present disclosure and to help understand the disclosure, and are not intended to limit the scope of the present disclosure.

[0229] Furthermore, it will be apparent to those skilled in the art that, in addition to the embodiments described in this disclosure, other modifications based on the technical concepts of this disclosure are possible. For example, some or all of the contents of one embodiment described above may be combined with some or all of one or more other embodiments, and such combinations are also included in the embodiments proposed in this disclosure.

Claims

1. A method performed by a STA (station) of a wireless local area network (WLAN) system, A step of receiving a first frame for initiating a transmission opportunity (TXOP) on a secondary channel from an AP (access point); and A step of transmitting a second frame including feedback information for non-primary channel access (NPCA) for the TXOP to the AP, A method wherein the second frame includes a first field for an association identifier (AID), a second field and a third field for indicating the feedback information, and a fourth field including parameters related to the NPCA.

2. In paragraph 1, The first field above is the AID11 field, A method wherein the above AID11 field includes an AID associated with the STA, is assigned 0, or is assigned a value indicating a control extension.

3. In paragraph 1, The above second field includes an Ack Type field, and the Ack Type field is assigned 0, The third field above is a TID (traffic identifier) ​​field, and the TID field is assigned 13. The method according to claim 1, wherein the fourth field includes a Block Ack bitmap field, and the parameters related to the NPCA included in the Block Ack bitmap field include at least one of a presence field, a time unit field, a basic NAV (network allocation vector) field, an NPCA duration field, an NPCH (NPCA channel) field, an OBSS (overlapping basic service set) information field, an NPCH channel information field, or an NPCA continuation field.

4. In paragraph 1, The first frame is a frame for transmitting an ICF (initial control frame) or PPDU (physical layer protocol data unit) for initiating the TXOP, The second frame is a frame for transmitting an ICR (initial control response) for the ICF or an acknowledgment for the PPDU, The first frame includes a trigger frame, and the trigger frame includes a BSRP (buffer status report poll) trigger frame, a BQRP (bandwidth query report poll) trigger frame, a basic trigger frame, or a MU-BAR (multi-user block ack request) trigger frame, A method wherein the second frame includes an M-BA (multi-STA block ack) frame or a multi-TID block ack frame.

5. In a method performed by an AP (access point) of a wireless local area network (WLAN) system, A step of transmitting a first frame to initiate a transmission opportunity (TXOP) on a secondary channel as an STA (station); and A step of receiving a second frame including feedback information for non-primary channel access (NPCA) for the TXOP from the STA, A method wherein the second frame includes a first field for an association identifier (AID), a second field and a third field for indicating the feedback information, and a fourth field including parameters related to the NPCA.

6. In paragraph 5, The first field above is the AID11 field, A method wherein the above AID11 field includes an AID associated with the STA, is assigned 0, or is assigned a value indicating a control extension.

7. In paragraph 5, The above second field includes an Ack Type field, and the Ack Type field is assigned 0, The third field above is a TID (traffic identifier) ​​field, and the TID field is assigned 13. The method according to claim 1, wherein the fourth field includes a Block Ack bitmap field, and the parameters related to the NPCA included in the Block Ack bitmap field include at least one of a presence field, a time unit field, a basic NAV (network allocation vector) field, an NPCA duration field, an NPCH (NPCA channel) field, an OBSS (overlapping basic service set) information field, an NPCH channel information field, or an NPCA continuation field.

8. In paragraph 5, The first frame is a frame for transmitting an ICF (initial control frame) or PPDU (physical layer protocol data unit) for initiating the TXOP, The second frame is a frame for transmitting an ICR (initial control response) for the ICF or an acknowledgment for the PPDU, The first frame includes a trigger frame, and the trigger frame includes a BSRP (buffer status report poll) trigger frame, a BQRP (bandwidth query report poll) trigger frame, a basic trigger frame, or a MU-BAR (multi-user block ack request) trigger frame, A method wherein the second frame includes an M-BA (multi-STA block ack) frame or a multi-TID block ack frame.

9. In STA(station), At least one transceiver; At least one processor communicatively coupled to said at least one transceiver; and At least one memory communicatively coupled to said at least one processor and storing instructions, The above instructions are executed individually or in any combination by the at least one processor, so that the STA: Receive a first frame to initiate a transmission opportunity (TXOP) on a secondary channel from an access point (AP), and The AP is configured to transmit a second frame including feedback information for non-primary channel access (NPCA) for the TXOP, The second frame includes a first field for an association identifier (AID), a second field and a third field for indicating the feedback information, and a fourth field including parameters related to the NPCA.

10. In paragraph 9, The first field above is the AID11 field, The AID11 field includes an AID associated with the STA, is assigned 0, or is assigned a value indicating a control extension.

11. In paragraph 9, The above second field includes an Ack Type field, and the Ack Type field is assigned 0, The third field above is a TID (traffic identifier) ​​field, and the TID field is assigned 13. The STA, wherein the fourth field includes a Block Ack bitmap field, and the parameters related to the NPCA included in the Block Ack bitmap field include at least one of a presence field, a time unit field, a basic NAV (network allocation vector) field, an NPCA duration field, an NPCH (NPCA channel) field, an OBSS (overlapping basic service set) information field, an NPCH channel information field, or an NPCA continuation field.

12. In paragraph 9, The first frame is a frame for transmitting an ICF (initial control frame) or PPDU (physical layer protocol data unit) for initiating the TXOP, The second frame is a frame for transmitting an ICR (initial control response) for the ICF or an acknowledgment for the PPDU, The first frame includes a trigger frame, and the trigger frame includes a BSRP (buffer status report poll) trigger frame, a BQRP (bandwidth query report poll) trigger frame, a basic trigger frame, or a MU-BAR (multi-user block ack request) trigger frame, The above second frame includes an M-BA (multi-STA block ack) frame or a multi-TID block ack frame.

13. In AP (access point), At least one transceiver; At least one processor communicatively coupled to said at least one transceiver; and At least one memory communicatively coupled to said at least one processor and storing instructions, The above instructions are executed individually or in any combination by the at least one processor, so that the AP: As an STA (station), transmit a first frame to initiate a TXOP (transmission opportunity) on a secondary channel, and From the STA, a second frame including feedback information for non-primary channel access (NPCA) for the TXOP is set to be received, An AP wherein the second frame includes a first field for an AID (association identifier), a second field and a third field for indicating the feedback information, and a fourth field including parameters related to the NPCA.

14. In paragraph 13, The first field above is the AID11 field, The above AID11 field contains an AID associated with the STA, is assigned 0, or is assigned a value to indicate a control extension.

15. In paragraph 13, The above second field includes an Ack Type field, and the Ack Type field is assigned 0, The third field above is a TID (traffic identifier) ​​field, and the TID field is assigned 13. The AP, wherein the fourth field includes a Block Ack bitmap field, and the parameters related to the NPCA included in the Block Ack bitmap field include at least one of a presence field, a time unit field, a basic NAV (network allocation vector) field, an NPCA duration field, an NPCH (NPCA channel) field, an OBSS (overlapping basic service set) information field, an NPCH channel information field, or an NPCA continuation field.

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