Broadcast TWT-based IDC operation method and device in wireless LAN system

Abstract

The present disclosure relates to an improved wireless LAN system. The present disclosure proposes a method and a device for an operation considering IDC to improve traffic reliability in an improved wireless LAN system. Specifically, the present disclosure proposes a method of a procedure for a broadcast TWT-based IDC operation, and a device for performing the method.

Description

Method and device for operating IDC based on broadcast TWT in wireless LAN system

[0001] The present disclosure relates to a wireless local area network (WLAN) system. Specifically, the present disclosure relates to an operating method and device that take into account in-device coexistence (IDC) 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] This disclosure proposes a method and device for operating a device that considers IDC to ensure traffic reliability in a wireless LAN system. Specifically, this disclosure proposes procedures for setting and operating a period for IDC operation. Furthermore, this disclosure proposes a frame and element structure for IDC operation.

[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) includes the steps of: transmitting a first frame to an access point (AP) for requesting setup of an in-device coexistence (IDC) target wakeup time (TWT) service period (SP); receiving a second frame from the AP for approving setup of the IDC TWT SP; and performing an IDC operation within the IDC TWT SP, wherein a broadcast TWT recommendation field of a first TWT element included in the first frame may include a first value for indicating that a TWT SP associated with the first frame is the IDC TWT SP, and a broadcast TWT recommendation field of a second TWT element included in the second frame may include a second value for indicating that a TWT SP associated with the second frame is the IDC TWT SP.

[0008] According to one embodiment of the present disclosure, a method performed by an access point (AP) includes the steps of: receiving a first frame for requesting setup of an in-device coexistence (IDC) target wakeup time (TWT) service period (SP) from a station (STA); transmitting a second frame for approving setup of the IDC TWT SP to the STA; and performing an IDC operation within the IDC TWT SP, wherein a broadcast TWT recommendation field of a first TWT element included in the first frame may include a first value for indicating that a TWT SP associated with the first frame is the IDC TWT SP, and a broadcast TWT recommendation field of a second TWT element included in the second frame may include a second value for indicating that a TWT SP associated with the second frame is the IDC TWT SP.

[0009] According to one embodiment of the present disclosure, a station (STA) includes a transceiver; and at least one processor connected to the transceiver, wherein the at least one processor is configured to: transmit a first frame to an access point (AP) for requesting setup of an in-device coexistence (IDC) target wakeup time (TWT) service period (SP), receive a second frame from the AP for approving setup of the IDC TWT SP, and perform an IDC operation within the IDC TWT SP, wherein a broadcast TWT recommendation field of a first TWT element included in the first frame may include a first value for indicating that a TWT SP associated with the first frame is the IDC TWT SP, and a broadcast TWT recommendation field of a second TWT element included in the second frame may include a second value for indicating that a TWT SP associated with the second frame is the IDC TWT SP.

[0010] According to one embodiment of the present disclosure, an access point (AP) includes a transceiver; and at least one processor connected to the transceiver, wherein the at least one processor is configured to: receive a first frame from a station (STA) for requesting setup of an in-device coexistence (IDC) target wakeup time (TWT) service period (SP), transmit a second frame to the STA for approving setup of the IDC TWT SP, and perform an IDC operation within the IDC TWT SP, wherein a broadcast TWT recommendation field of a first TWT element included in the first frame may include a first value for indicating that a TWT SP associated with the first frame is the IDC TWT SP, and a broadcast TWT recommendation field of a second TWT element included in the second frame may include a second value for indicating that a TWT SP associated with the second frame is the IDC TWT SP.

[0011] According to the various embodiments proposed in this disclosure, the reliability of traffic transmission and reception in a wireless LAN system can be improved. Furthermore, by simplifying the procedures for improving reliability, the efficiency of device operation can also be improved.

[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 an exemplary format of a target wakeup time (TWT) element related to the present disclosure.

[0021] FIG. 10 illustrates an exemplary format of an individual TWT parameter set field related to the present disclosure.

[0022] FIG. 11 illustrates an exemplary format of a broadcast TWT parameter set field related to the present disclosure.

[0023] FIG. 12 illustrates an exemplary format of a broadcast TWT parameter set field related to the present disclosure.

[0024] FIG. 13 is a diagram for explaining an IDC TWT SP (service period) according to one embodiment of the present disclosure.

[0025] FIG. 14 is a diagram illustrating the operation of devices for an IDC TWT SP according to one embodiment of the present disclosure.

[0026] FIG. 14a is a diagram illustrating the format of a frame for a request of an IDC TWT SP according to one embodiment of the present disclosure.

[0027] FIG. 15 illustrates an exemplary format of a broadcast TWT parameter set field according to one embodiment of the present disclosure.

[0028] FIG. 16 illustrates exemplary values ​​of a broadcast TWT recommendation field according to one embodiment of the present disclosure.

[0029] FIG. 16a illustrates further exemplary values ​​of a broadcast TWT recommendation field according to one embodiment of the present disclosure.

[0030] FIG. 17 is a diagram illustrating the operation of devices for an IDC TWT SP according to one embodiment of the present disclosure.

[0031] FIG. 18 is a flowchart illustrating signaling of devices for IDC operation according to one embodiment of the present disclosure.

[0032] FIG. 19 is a flowchart illustrating the operation of a non-AP STA according to an embodiment of the present disclosure.

[0033] FIG. 20 is a flowchart illustrating the operation of an AP according to an embodiment of the present disclosure.

[0034] FIG. 21 is a flowchart illustrating the operation of a non-AP STA according to an embodiment of the present disclosure.

[0035] FIG. 22 is a flowchart illustrating the operation of an AP 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 ensure that the gist of the present disclosure is conveyed more clearly without obscuring it by omitting unnecessary explanations.

[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 next-generation wireless LAN system based on a new standards document that improves upon the 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] An exemplary structure of a wireless LAN system related to the present disclosure is illustrated.

[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 uses a non-contention-based channel access method using 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 frame transmission 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 frame transmission. 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 selected by it, and then starts frame transmission. 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] Below, we explain TWT (target wakeup time).

[0122] TWT is a power saving (PS) technology that can improve the energy efficiency of non-AP STAs by defining a predetermined service period (SP) and sharing information about the SP among devices to reduce contention of the medium. An STA that performs a request / suggest / demand in the TWT setup phase can be called a TWT requesting STA. In addition, an AP that responds with acceptance / rejection to the request / suggest / demand of a TWT requesting STA can be called a TWT responding AP (or TWT responding STA). TWT operation can be divided into TWT operation based on individual TWT and TWT operation based on broadcast TWT.

[0123] FIG. 9 illustrates an exemplary format of a target wakeup time (TWT) element related to the present disclosure.

[0124] The TWT element illustrated in (a) of FIG. 9 may be included in a TWT setup frame, a beacon frame, a probe response frame, or a (re)association response frame and transmitted and received between a TWT requesting STA and a TWT responding AP. The TWT element may include a 1-octet element identifier (ID) field, a 1-octet length field, a 1-octet control field, and a variable-length TWT parameter information field. The control field of the TWT element has the same format for individual TWTs and broadcast TWTs, and the TWT parameter information field of the TWT element has different formats for individual TWTs and broadcast TWTs.

[0125] Hereinafter, each subfield included in the control field of the TWT element illustrated in (b) of Fig. 9 will be described in detail. The NDP (null data packet) paging indication subfield may include a value of 1 if an NDP paging field exists in the TWT parameter information field, and may include a value of 0 if an NDP paging field does not exist in the TWT parameter information field.

[0126] The responder PM mode subfield may include a value indicating a power management (PM) mode.

[0127] The negotiation type subfield may contain a value to indicate whether the information contained in the TWT element is about parameter negotiation of a broadcast TWT, parameter negotiation of an individual TWT, or wake target beacon transmission time (TBTT) interval.

[0128] If the value of the negotiation type subfield is 0, the TWT element is for a future individual TWT SP start time, and the TWT parameter information field contains one individual TWT parameter set. This individual TWT parameter set may correspond to an individual TWT negotiation between a TWT requesting STA and a TWT responding STA, or may correspond to an individual TWT announcement of a TWT responding AP.

[0129] If the value of the negotiation type subfield is 1, the TWT element is for the next TBTT time, and the TWT parameter information field contains one individual TWT parameter set. This individual TWT parameter set may correspond to the wake TBTT and wake interval negotiation between the TWT scheduled STA and the TWT scheduling AP.

[0130] If the value of the negotiation type subfield is 2, the TWT element is for a future broadcast TWT SP start time, and the TWT parameter information field contains one or more broadcast TWT parameter sets. These broadcast TWT parameter sets may correspond to providing a broadcast TWT schedule to a TWT scheduled STA by including a TWT element in a broadcast management frame transmitted by the TWT scheduling AP.

[0131] If the value of the negotiation type subfield is 3, the TWT element is for a future broadcast TWT SP start time, and the TWT parameter information field contains one or more broadcast TWT parameter sets. These broadcast TWT parameter sets may correspond to managing membership in the broadcast TWT schedule by including the TWT element in individually addressed management frames transmitted by either the TWT scheduled STA or the TWT scheduling AP.

[0132] That is, the MSB (most significant bit) of the negotiation type subfield can be interpreted as a broadcast field. If the value of the broadcast field is 1 (i.e., the value of the MSB of the negotiation type subfield is 1), the TWT element can contain one or more broadcast TWT parameter sets. If the value of the broadcast field is 0 (i.e., the value of the MSB of the negotiation type subfield is 0), the TWT element can contain one individual TWT parameter set. A TWT element whose broadcast field has a value of 1 (i.e., the value of the MSB of the negotiation type subfield is 1) can be referred to as a broadcast TWT element.

[0133] If the TWT information frame disabled subfield contains a value of 1, it indicates that reception of TWT information frames by the STA is disabled; otherwise, the TWT information frame disabled subfield may contain a value of 0.

[0134] The wake duration unit subfield indicates the unit of the nominal minimum TWT wake duration field. If the unit of the nominal minimum TWT wake duration field is 256 us, the wake duration unit subfield contains the value 0, and if the unit of the nominal minimum TWT wake duration field is TU (time unit), the wake duration unit subfield can contain the value 1. If it is not a HE / EHT STA, the wake duration unit subfield can contain the value 0.

[0135] The link ID bitmap present field may contain a value to indicate whether the TWT parameter information field includes a link ID bitmap subfield.

[0136] The aligned TWT field may contain a value indicating whether the TWT parameter information field includes an aligned TWT link bitmap subfield.

[0137] FIG. 10 illustrates an exemplary format of an individual TWT parameter set field related to the present disclosure.

[0138] In the individual TWT parameter set field illustrated in (a) of FIG. 10, the request type subfield may have the same size in the individual TWT parameter set field and the broadcast TWT parameter set field, but may have different detailed configurations. Specific details regarding the request type subfield will be described later.

[0139] The target wake time subfield indicates the start time of the upcoming individual / broadcast TWT SP.

[0140] The TWT group assignment subfield contains information for providing information about the TWT group assigned to the TWT requesting STA. The TWT requesting STA can use this information to calculate the TWT value within the TWT group. The TWT value of the TWT requesting STA may be equal to the value of the zero offset and the value of the TWT offset multiplied by the value of the TWT unit.

[0141] The nominal maximum TWT wake duration subfield indicates the minimum unit within which a TWT requesting STA expects to wake up to complete the exchange of frames associated with the TWT flow identifier during the TWT wake duration. The TWT wake duration may mean the average time between consecutive TWT SPs expected by the TWT requesting STA.

[0142] The TWT Wake Interval Mantissa subfield may be expressed as a binary value of the TWT wake interval value in microseconds.

[0143] The TWT channel subfield may contain a bitmap indicating allowed channels. When the TWT element is transmitted by a TWT requesting STA, the TWT channel subfield may contain a bitmap indicating a channel that the TWT requesting STA requests to use as a temporary default channel during the TWT SP. When the TWT element is transmitted by a TWT responding AP, the TWT channel subfield may contain a bitmap indicating a channel on which TWT requests are allowed.

[0144] The NDP paging subfield may include information related to the identifier of the STA being paged, the maximum number of TWT wake intervals between NDP paging frames, etc.

[0145] The Link ID Bitmap subfield may include information to indicate whether a TWT element transmitted by an STA associated with a multi-link device (MLD) (STA affiliated with MLD) applies to a specific link.

[0146] The Aligned TWT Link Bitmap field may contain information to indicate a link having an aligned TWT SP for the link indicated by the Link ID Bitmap subfield.

[0147] Next, we will explain the detailed configuration of the request type subfield.

[0148] The TWT request subfield illustrated in (b) of FIG. 10 can indicate whether the TWT element is transmitted by a TWT requesting STA or a TWT responding AP. If the value of the TWT request subfield is 1, it can indicate a TWT requesting STA or a TWT scheduled STA, and if the value of the TWT request subfield is 0, it can indicate a TWT responding AP (or, a TWT responding STA) or a TWT scheduling AP.

[0149] The TWT setup command subfield can represent commands such as request, suggest, demand, grouping, accept, alternate, dictate, and reject.

[0150] The trigger subfield indicates whether a trigger frame is used in the TWT SP. If the value of the trigger subfield is 1, the trigger is used, and if the value of the trigger subfield is 0, the trigger may not be used.

[0151] The implicit subfield can indicate whether the TWT is implicit or explicit. A value of 1 in the implicit subfield indicates implicit TWT, while a value of 0 in the implicit subfield indicates explicit TWT.

[0152] The flow type subfield may indicate the type of interaction between a TWT requesting STA (or, TWT scheduled STA) and a TWT responding AP (or TWT scheduling AP). If the value of the flow type subfield is 1, it may mean announced TWT in which the STA sends a wake-up signal to the AP by transmitting a PS-Poll or APSD (automatic power save delivery) trigger frame before a non-trigger frame is transmitted from the AP to the STA. If the value of the flow type subfield is 0, it may mean unannounced TWT.

[0153] The TWT flow identifier subfield may include a 3-bit value to uniquely identify specific information about a TWT request in other requests made between the same TWT requesting STA and TWT responding AP pair.

[0154] The TWT wake interval exponent subfield may include a value representing the TWT wake interval value in binary microseconds. For an individual TWT, the TWT wake interval exponent subfield may indicate the interval between individual TWT SPs. The TWT wake interval of a TWT requesting STA may be defined as TWT Wake Interval Mantissa * 2 * TWT Wake Interval Exponent.

[0155] The TWT protection subfield can indicate whether a TWT protection mechanism is used. If the value of the TWT protection subfield is 1, a transmit opportunity (TXOP) within a TWT SP can be initiated with a NAV protection mechanism, such as a (MU)RTS / CTS or CTS-to-self frame. If the value of the TWT protection subfield is 0, the NAV protection mechanism may not be applied.

[0156] Fig. 11 illustrates an exemplary format of a broadcast TWT parameter set field related to the present disclosure. A detailed description of subfields in the format of Fig. 11 that overlap with the format of Fig. 10 is omitted.

[0157] In the broadcast TWT parameter set field illustrated in (a) of FIG. 11, the request type subfield may include the following subfields in addition to the various subfields described in FIG. 10.

[0158] The last broadcast parameter set subfield illustrated in (b) of FIG. 11 indicates whether the corresponding broadcast TWT parameter set field is the last broadcast TWT parameter set. If the value of the last broadcast parameter set subfield is 1, it indicates that the corresponding broadcast TWT parameter set field is the last broadcast TWT parameter set within the TWT element, and if the value of the last broadcast parameter set subfield is 0, it may indicate that there is a next broadcast TWT parameter set within the TWT element.

[0159] The Broadcast TWT Recommendation subfield contains 3 bits and can be a value from 0 to 7 indicating recommendations for the frame types transmitted by the AP during the Broadcast TWT SP.

[0160] The last bit of the Request Type subfield of the Broadcast TWT Parameter Set field may be reserved.

[0161] A detailed description of the broadcast TWT info field and the restricted TWT traffic info field included in the broadcast TWT parameter set field is provided below with reference to FIG. 12.

[0162] FIG. 12 illustrates an exemplary format of a broadcast TWT parameter set field related to the present disclosure.

[0163] The broadcast TWT parameter set field illustrated in (a) of FIG. 12 may include a 2-octet broadcast TWT info subfield and a 0 or 3-octet restricted TWT traffic info subfield. Among the other subfields included in the broadcast TWT parameter set field, any content that overlaps with the subfields described in FIG. 10 is omitted.

[0164] The broadcast TWT info subfield may include a restricted TWT traffic info present subfield, a restricted TWT schedule info subfield, a broadcast TWT identifier (ID) subfield, and a broadcast TWT persistence subfield.

[0165] The restricted TWT traffic info present subfield illustrated in (b) of FIG. 12 indicates the presence or absence of restricted TWT traffic information (restricted TWT traffic info subfield). If the value of the restricted TWT traffic info present subfield is 1, the restricted TWT traffic info subfield is present. For non-EHT STAs, this field value may be reserved for other purposes.

[0166] The restricted TWT schedule info subfield is included when the restricted TWT parameter set subfield is conveyed in a TWT element whose negotiation type field has a value of 2.

[0167] If the value of the restricted TWT schedule information subfield is 0, the schedule of the restricted TWT (R-TWT) means an idle R-TWT schedule, which means that there are no member STAs in the R-TWT schedule or the schedule is suspended for all STAs.

[0168] If the value of the restricted TWT schedule information subfield is 1, it means that the schedule of the corresponding R-TWT is an active R-TWT schedule, which means that there is at least one member STA in the corresponding R-TWT schedule.

[0169] If the value of the limited TWT schedule information subfield is 2, it means that the corresponding R-TWT schedule is a full R-TWT schedule, which means that the resources of the corresponding R-TWT schedule are insufficient or there are too many existing member STAs to accept a new STA as a member.

[0170] If the value of the Restricted TWT Schedule Information subfield is 3, the corresponding R-TWT schedule means that the advertised R-TWT schedule is activated and is for the AP corresponding to the non-transmitted BSSID that is a member of the same multiple BSSID set or co-hosted BSSID set that transmits the Restricted TWT Schedule Information subfield.

[0171] The Broadcast TWT Identifier subfield indicates the broadcast ID of a particular broadcast TWT to which the STA requests participation or provides TWT parameters, depending on the value of the TWT setup command subfield of the TWT element.

[0172] The broadcast TWT persistence subfield is a value expressed as the number of TBTTs for the interval in which the broadcast TWT SP corresponding to the corresponding broadcast TWT parameter set is included. For example, if the value of the broadcast TWT persistence subfield is 10, it means that the broadcast TWT SP configured with the corresponding parameters is operated for the time that 10 beacon frames are transmitted, and if the value is 255, it means that the broadcast TWT SP is applied permanently.

[0173] The restricted TWT traffic info subfield may include a traffic info control subfield, a restricted TWT DL TID (traffic identifier) ​​bitmap subfield, and a restricted TWT UL TID bitmap subfield.

[0174] The traffic information control subfield illustrated in (c) of FIG. 12 may include a DL TID bitmap valid subfield and a UL TID bitmap valid subfield, and six bits included in the traffic information control subfield may be reserved.

[0175] The restricted TWT DL TID bitmap field and the restricted TWT UL TID bitmap field represent TIDs identified as latency sensitive traffic of the downlink and uplink, respectively, in bitmap form.

[0176] The DL TID bitmap valid subfield and the UL TID bitmap valid subfield included in the traffic information control subfield illustrated in (d) of FIG. 12 indicate whether the restricted TWT DL TID bitmap subfield and the restricted TWT UL TID bitmap subfield are included in the restricted TWT traffic information subfield, respectively. When the value of the DL TID bitmap valid subfield (or the UL TID bitmap valid subfield) is 1, this indicates that the restricted TWT DL TID bitmap subfield (or the restricted TWT UL TID bitmap subfield) is included in the restricted TWT traffic information subfield, and when the value of the DL TID bitmap valid subfield (or the UL TID bitmap valid subfield) is 0, all TIDs are classified as delay-sensitive traffic within the corresponding R-TWT membership.

[0177] FIG. 13 is a diagram for explaining an IDC TWT SP (service period) according to one embodiment of the present disclosure.

[0178] First, let's explain in-device coexistence (IDC). As devices evolve, they (including non-AP STAs and APs) support a variety of different radio access technologies (RATs). Furthermore, as devices become increasingly smaller, antennas and transceivers supporting multiple RATs are mounted adjacent to each other. Alternatively, a single radio frequency (RF) chain within a device may be shared among different RATs. In particular, when different RATs occupy adjacent frequency bands, seamless coexistence (IDC) of different RATs within a device is essential, and the need to support such IDC is growing. This IDC must be considered across various RATs, such as wireless LAN (WLAN), Bluetooth (BT), Bluetooth low-energy (BLE), peer-to-peer (P2P), ultra-wideband (UWB), licensed assisted access (LAA), and NR unlicensed (NR-U).

[0179] IDC can be considered for a given time interval, and these time intervals may be periodic. For example, consider a situation where multiple adjacent devices within a BSS perform discovery or ranging for the same service during a specific time interval. In such cases, these time intervals may occur periodically, and IDC must be efficiently resolved to ensure that multiple devices seamlessly utilize different wireless access technologies during these periodic periods. This situation can be interpreted as periodic unavailability of the WLAN, and effective support for IDC operation is necessary to improve the capacity of multiple devices.

[0180] Accordingly, various discussions are currently underway to efficiently control, improve, or resolve IDC. In particular, the 802.11bn standard document discusses various issues related to improving reliability. Therefore, from this perspective, it is necessary to propose methods for operating or controlling IDC through efficient and streamlined procedures.

[0181] In this disclosure, embodiments of a method and apparatus for setting up (or configuring) and operating an IDC TWT SP are proposed to effectively support IDC operation of devices.

[0182] FIG. 13 illustrates a scenario in which multiple STAs (non-AP STAs) operate within a BSS of an AP. Among the multiple STAs, one or more adjacent STAs (1310) may utilize wireless access technologies other than WLAN for specific services, and the operation of the WLAN may be affected by the operation of the other wireless access technologies. According to an embodiment, a time period for supporting IDC of one or more STAs (1310) may be defined, and this time period may be referred to as an IDC TWT SP (in-device coexistence target wakeup time service period). As described above, since IDC may occur periodically, the IDC TWT SP, which is a time period for supporting IDC, may also be defined periodically as illustrated in FIG. 13. According to an embodiment, the AP and STAs (1310) may suspend, limit, or minimize WLAN operation during the IDC TWT SP, and a detailed description of the IDC TWT SP will be provided below. Hereinafter, IDC TWT SP may also be referred to as IDC SP (in-device coexistence service period), and IDC TWT SP and IDC SP may be described as different names for the same time interval.

[0183] FIG. 14 is a diagram illustrating the operation of devices for an IDC TWT SP according to one embodiment of the present disclosure.

[0184] In the illustrated embodiment, STA1, STA2, and STA3 may be non-AP STAs adjacent to each other within a BSS provided by the AP. STA1, which is a non-AP STA, transmits a frame to the AP to request the creation, setup, or configuration of an IDC TWT SP (1410), and this frame may include a TWT element according to an embodiment to be described later. The AP transmits a frame to STA1 to approve (or respond to) the creation, setup, or configuration of an IDC TWT SP according to the received request (1420), and this frame may include a TWT element according to an embodiment to be described later. This series of processes may be referred to as an IDC TWT SP setup process. Hereinafter, a non-AP STA requesting the creation, setup, or configuration of an IDC TWT SP is referred to as an IDC TWT SP requesting STA, and an AP responding to the creation, setup, or configuration of an IDC TWT SP to support the IDC operation of the IDC TWT SP requesting STA is referred to as an IDC TWT SP responding AP.

[0185] According to one embodiment, a frame (1410) that an IDC TWT SP requesting STA (STA1 of FIG. 14) transmits to an IDC TWT SP responding AP for a request of an IDC TWT SP may include a TWT element, and this frame may mean various types of frames such as a management frame, a control frame, an action frame, or a new type of frame. Alternatively, according to one embodiment, a frame including a TWT element transmitted by an IDC TWT SP requesting STA may be a TWT setup frame, but is not limited to this type of frame.

[0186] According to one embodiment, a frame (1420) that an IDC TWT SP responding AP transmits to an IDC TWT SP requesting STA for a response from an IDC TWT SP may include a TWT element, and such frame may include various types of frames such as a management frame, a control frame, an action frame, or a new type of frame. Alternatively, according to one embodiment, a frame including a TWT element transmitted by an IDC TWT SP responding AP may be a TWT response frame, but is not limited to such types of frames.

[0187] FIG. 14A is a diagram illustrating a format of a frame for requesting an IDC TWT SP according to an embodiment of the present disclosure. FIG. 14A illustrates a format structure of a frame that an IDC TWT SP requesting STA (STA1 of FIG. 14) transmits to an IDC TWT SP responding AP for requesting an IDC TWT SP according to an embodiment. In an embodiment, the frame transmitted by the IDC TWT SP requesting STA may include a channel usage request frame, and it is to be understood that this name is merely an example and may be called by another name.

[0188] According to one embodiment, the channel usage request frame may have a type of action frame, and the channel usage request frame may include exemplary fields illustrated in (a) of FIG. 14A. The channel usage request frame may include a Channel Usage Elements field (1440) for requesting creation, setup, or configuration of an IDC TWT SP.

[0189] In one embodiment, the Channel Usage Elements field (1440) may include one or more fields illustrated in (b) of FIG. 14A. If the Usage Mode field (1450) included in the Channel Usage Elements field (1440) indicates a specific value, a channel usage request frame including the Channel Usage Elements field (1440) may be regarded as or utilized as a frame for requesting periodic IDC. Specifically, if the channel usage request frame includes the Channel Usage Elements field (1440) and the TWT element field, and the Usage Mode field (1450) of the Channel Usage Elements field (1440) indicates a predetermined specific value, the channel usage request frame may be utilized as a frame for requesting to set up, generate, or configure a time interval defined according to the TWT element field as an IDC TWT SP.

[0190] The embodiment of Fig. 14 will be described below. According to one embodiment, the IDC TWT SP starts after a predetermined time (i.e., TWT) has passed since the IDC TWT SP responding AP transmits a response to the IDC TWT SP requesting STA, and information about the time at which the IDC TWT SP starts and information about the length of time the IDC TWT SP lasts can be negotiated during a frame exchange process between the IDC TWT SP requesting STA and the IDC TWT SP responding AP.

[0191] The frame (1430) transmitted (or broadcast) by the IDC TWT SP responding AP may include a TWT element for notifying the IDC TWT SP agreed upon with the IDC TWT SP requesting STA, and STA1 and STA2 receiving this frame (1430) may obtain information about the IDC TWT SP from the TWT element included in the frame (1430). Accordingly, STA1 and STA2 may know about the IDC TWT SP that arrives after a predetermined time (i.e., the remaining time until the start time of the TWT and IDC TWT SP) from the frame. Non-AP STAs (i.e., STA1 and STA2) that recognize the IDC TWT SP may join the membership for the IDC TWT SP. When an IDC TWT SP is periodically negotiated between an IDC TWT SP requesting STA and an IDC TWT SP responding AP for periodic IDC, this period may be referred to as a TWT interval or an IDC SP interval.

[0192] According to one embodiment, a frame (1430) that an IDC TWT SP responding AP transmits (or broadcasts) to notify an IDC TWT SP may include a TWT element, and such frame may include various types of frames such as a management frame, a control frame, an action frame, etc. According to one embodiment, a frame including a TWT element that an IDC TWT SP responding AP transmits to notify an IDC TWT SP may be a beacon frame, a probe response frame, a (re)association response frame, but is not limited to these types of frames.

[0193] According to one embodiment of the IDC TWT SP setup process of FIG. 14, a TWT element included in a frame that STA1 transmits to an AP may have a negotiation type subfield having a value of 3 (i.e., indicating a broadcast TWT membership exchange), a TWT request subfield having a value of 1 (i.e., indicating a TWT scheduled STA), a TWT setup command subfield having a value of 0, 1, or 2 (i.e., indicating a request, suggest, or demand TWT), a nominal minimum TWT wake duration subfield having a value that may indicate an IDC event duration, and a broadcast TWT recommendation subfield having a value of 5 or one of other reserved values ​​(i.e., indicating an IDC TWT SP).

[0194] According to one embodiment of the IDC TWT SP setup process of FIG. 14, the TWT element included in the frame that the AP transmits to STA1 may have a TWT request subfield with a value of 3 (i.e., indicating that it is a TWT scheduling AP) and a broadcast TWT recommendation subfield with a value of 5 or one of other reserved values ​​(i.e., indicating that it is an IDC TWT SP) to indicate that the IDC TWT SP responding AP acknowledges and responds to the creation / setup / configuration of the IDC TWT SP.

[0195] According to one embodiment of the IDC TWT SP setup process of FIG. 14, the TWT element included in the beacon frame transmitted by the AP may have a value of the broadcast TWT recommendation subfield of 5 or one of other reserved values ​​to inform the IDC TWT SP responding AP of the setup IDC TWT SP (i.e., indicating an IDC TWT SP).

[0196] Fig. 15 illustrates an exemplary format of a broadcast TWT parameter set field according to an embodiment of the present disclosure. Fig. 15 illustrates an exemplary format of a broadcast TWT parameter set field of a TWT element used for setting up an IDC TWT SP proposed in the present disclosure. Among the fields / subfields illustrated in (a), (b), and (c) of Fig. 15, a detailed description of the overlapping content with the content described for the broadcast TWT parameter set field in Figs. 11 and 12 will be omitted.

[0197] According to one embodiment, the broadcast TWT parameter set field format illustrated in (a) of FIG. 15 may further include an IDC information (IDC info) field in addition to the various fields described above (1510). The IDC information field may include various parameters and information required for non-AP STAs and STAs to operate in the IDC TWT SP. For example, the IDC information field may include parameters and information required for non-AP STAs to suspend, restrict, or minimize WLAN operations in the IDC TWT SP. According to one embodiment, the IDC information field may include information related to the characteristics or types of traffic that an AP can transmit to non-AP STAs within the IDC TWT SP (e.g., allowed access category, whether it is emergency traffic, whether it is low latency traffic, remaining delay bound value, etc.). According to another embodiment, the IDC information field may also include a list of SCS (stream classification service) IDs of traffic that must be processed within the IDC TWT SP. According to this embodiment, when traffic mapped to an SCS ID included in the SCS ID list is buffered in the AP, if the AP determines that the preset QoS is not satisfied before the end of the IDC TWT SP, the AP may attempt to transmit the traffic mapped to the SCS ID to a non-AP STA even within the IDC TWT SP period. According to another embodiment, parameters and information such as NSS (number of spatial streams), BW (bandwidth), Tx / Rx (transmission and reception) mode, etc., applicable to the IDC TWT SP may be included in the IDC information field, but the information and parameters included in the IDC TWT SP are not limited to these examples.

[0198] Among the subfields of the request type field illustrated in (b) of FIG. 15, the broadcast TWT recommendation subfield (1520) includes 3 bits. According to one embodiment, the broadcast TWT recommendation subfield (1520) may include one of the reserved values ​​5-7 (e.g., value 5) to indicate that the TWT element includes the IDC information field (1510) described above. The values ​​indicated by the 3 bits of the broadcast TWT recommendation subfield (1520) will be described in detail later in FIG. 16.

[0199] FIG. 16 illustrates exemplary values ​​of a broadcast TWT recommendation field according to an embodiment of the present disclosure. As previously described, the broadcast TWT recommendation subfield included in the request type field of the TWT element includes three bits, and the broadcast TWT recommendation subfield according to an embodiment can represent different meanings depending on the values ​​indicated by the three bits.

[0200] In one embodiment, when the value of the Broadcast TWT Recommendation field is 0, it indicates that there are no restrictions on frames transmitted during a broadcast TWT SP. When the value of the Broadcast TWT Recommendation field is 1, it indicates that frames transmitted by a TWT scheduled STA during a broadcast TWT SP are recommended to be restricted to solicited status and solicited feedback, and random access (RA) is not allowed. When the value of the Broadcast TWT Recommendation field is 2, it indicates that frames transmitted by a TWT scheduled STA during a broadcast TWT SP are recommended to be restricted to solicited status and solicited feedback, and random access (RA) is allowed. When the value of the Broadcast TWT Recommendation field is 3, it indicates that there is no restriction on the frames transmitted during the broadcast TWT SP for opportunistic power save (OPS), but the AP may transmit a traffic indicator map (TIM) frame or a fast initial link setup (FILS) discovery frame at the beginning of each TWT SP. When the value of the Broadcast TWT Recommendation field is 4, it indicates that the broadcast TWT SP corresponds to a restricted TWT (R-TWT).

[0201] According to one embodiment, a TWT element included in a frame related to an IDC TWT SP may include a broadcast TWT recommendation field, and when the value of the broadcast TWT recommendation field is one of the reserved values ​​(e.g., 5, 6, or 7), the broadcast TWT recommendation field may indicate that the broadcast TWT SP is an IDC TWT SP (1610). When the value of the broadcast TWT recommendation field is one of the reserved values ​​(or another value distinct from the predefined values), a broadcast TWT parameter included in the TWT element may specify an IDC TWT SP for indicating periodic unavailability of the WLAN.

[0202] According to one embodiment, when the broadcast TWT recommendation field includes any one of the reserved values ​​(as an example, 5 is illustrated in 1610 of FIG. 16), during the IDC TWT SP indicated by the broadcast TWT recommendation field, the AP (i.e., the IDC TWT SP responding AP) may not poll, schedule downlink, or trigger uplink to member STAs, except for negotiated traffic types such as a particular access category (e.g., AC_VO) or a specific traffic characteristic (e.g., low latency traffic). Furthermore, the member STAs may not respond to the AP due to IDC operation. In one embodiment, a member STA may include a non-AP STA that performed the AP and IDC TWT SP setup (i.e., an IDC TWT SP requesting STA), and may also include other non-AP STAs that have joined the membership of the IDC TWT SP.

[0203] FIG. 16A illustrates further exemplary values ​​of the broadcast TWT recommendation field according to an embodiment of the present disclosure. In the embodiment of FIG. 16A, when the broadcast TWT recommendation field includes another one of the reserved values ​​(the case of 6 is illustrated as an example in 1620 of FIG. 16), the AP (i.e., the IDC TWT SP responding AP) may notify non-AP STAs associated with it that it performs an IDC operation within the interval corresponding to the IDC TWT SP corresponding to the broadcast TWT recommendation field. That is, the AP may notify that it cannot perform communication with or support non-AP STAs due to the IDC operation within the interval corresponding to the IDC TWT SP corresponding to the broadcast TWT recommendation field.

[0204] FIG. 16A illustrates further exemplary values ​​of the broadcast TWT recommendation field according to an embodiment of the present disclosure. In the embodiment of FIG. 16A, when the broadcast TWT recommendation field includes another one of the reserved values ​​(7 is illustrated as an example in 1630 of FIG. 16), the AP (i.e., the IDC TWT SP responding AP) may inform non-AP STAs associated with it that it performs an IDC operation outside the interval corresponding to the IDC TWT SP corresponding to the broadcast TWT recommendation field. That is, the AP may inform that it cannot perform communication with or support non-AP STAs due to the IDC operation outside the interval corresponding to the IDC TWT SP corresponding to the broadcast TWT recommendation field.

[0205] According to one embodiment, a member STA associated with an IDC TWT SP may perform wireless communication using a wireless access technology other than WLAN within the IDC TWT SP interval. Accordingly, the IDC TWT SP responding AP may not transmit a buffered downlink frame to the member STA within the IDC TWT SP interval set at the request of the IDC TWT SP requesting STA, or may not poll to request an uplink frame. In one embodiment, even within the IDC TWT SP interval, the IDC TWT SP responding AP may transmit an ICF (initial control frame) or a PS-poll frame to the IDC TWT SP requesting STA and the member STA to check whether the WLAN of the IDC TWT SP requesting STA and the member STA is available. In addition, if the pre-agreed stream classification service (SCS) between the IDC TWT SP responding AP and the IDC TWT SP requesting STA (and member STA) corresponds to high priority or low latency traffic, or if the remaining delay bound is low, the IDC TWT SP responding AP may transmit an ICF to the IDC TWT SP requesting STA (and member STA) even if it is within the IDC TWT SP in order to process the traffic. However, the IDC TWT SP responding AP cannot be guaranteed to receive an ICR (initial control response) from the IDC TWT SP requesting STA (and member STA).

[0206] In one embodiment, for special traffic, it may be pre-negotiated between an IDC TWT SP responding AP and an IDC TWT SP requesting STA (and member STA) to support transmission and reception even within the IDC TWT SP. This action may mean overriding the IDC TWT SP operation, and may be performed by indicating a specific SCS with an SCS identifier (ID), traffic type, or traffic ID that is deemed to be of high importance or urgency.

[0207] Traffic according to this embodiment can be identified by SCS ID. For traffic negotiated through a specific SCS ID, the IDC TWT SP requesting STA (and member STA) must be able to receive the traffic from the IDC TWT SP responding AP by switching the WLAN to an available state at the time when reception of the traffic mapped to the SCS ID is expected, even if it is within the IDC TWT SP. If the IDC TWT SP responding AP determines that the traffic classified by the SCS ID negotiated with the IDC TWT SP requesting STA (and member STA) is buffered and that the traffic does not satisfy the delay bound or delay requirement if it is not transmitted within the IDC TWT SP section, the IDC TWT SP responding AP can check the WLAN available state by polling the IDC TWT SP requesting STA (and member STA) even if it is within the IDC TWT SP section and transmit the traffic to the IDC TWT SP requesting STA (and member STA) with priority. The operation according to the above-described embodiment may be called an IDC TWT SP interruption.

[0208] According to one embodiment, a non-AP STA (i.e., an IDC TWT SP requesting STA) may additionally transmit information related to IDC TWT SP interruption within a frame transmitted to request the AP (i.e., an IDC TWT SP responding AP) to create an IDC TWT SP. For example, the information related to IDC TWT SP interruption may include information related to characteristics or types of traffic that the AP may transmit to the non-AP STA within the IDC TWT SP (e.g., allowed access category, whether it is emergency traffic, whether it is low latency traffic, remaining delay bound value, etc.). In addition, the information related to IDC TWT SP interruption may include a list of SCS IDs of traffic that should be processed within the IDC TWT SP. According to this embodiment, if traffic mapped to an SCS ID included in the SCS ID list is buffered in the AP, and the AP determines that the preset QoS is not satisfied before the end of the IDC TWT SP, the AP may attempt to transmit the traffic mapped to the SCS ID to a non-AP STA even within the IDC TWT SP period.

[0209] According to one embodiment, information related to IDC TWT SP interruption may be transmitted by being included in a subfield within the IDC information field (1510) of FIG. 15 (a). According to another embodiment, information related to IDC TWT SP interruption may be transmitted to the AP by being included in some of other elements, parameters, or fields (or subfields) included in a frame for a request for IDC TWT SP creation / configuration / setup / update transmitted by a non-AP STA, in addition to the IDC information field (1510) of FIG. 15 (a).

[0210] According to one embodiment, if a frame transmitted by a non-AP STA to request creation / configuration / setup / update of an IDC TWT SP includes a field related to IDC TWT SP interruption, the AP may determine that the traffic corresponding to the information included in the field related to IDC TWT SP interruption does not satisfy the QoS condition that the traffic must satisfy if the traffic corresponding to the information included in the field related to IDC TWT SP interruption is buffered in the AP and the traffic is not processed within the IDC TWT SP time period. According to this embodiment, the AP may transmit a polling frame for transmitting the frame to the non-AP STA even within the IDC TWT SP period, or perform downlink frame scheduling to the non-AP STA. If the non-AP STA responds to the polling of the AP, the AP may transmit a frame corresponding to the field related to IDC TWT SP interruption to the non-AP STA. An operation of transmitting traffic within the IDC TWT SP period according to the above-described embodiment may be referred to as an IDC TWT SP interruption.

[0211] According to one embodiment, information related to IDC TWT SP interruption may be included in a frame for a non-AP STA (i.e., an IDC TWT SP requesting STA) to request creation / configuration / setup of an IDC TWT SP, as well as in a frame transmitted by a non-AP STA to an AP to update IDC TWT SP related parameters.

[0212] Tables 1 and 2 below illustrate exemplary structures of control fields and broadcast TWT parameter set fields and their values ​​included in a TWT element, according to the embodiments described in FIGS. 14, 15, and 16, and illustrate examples of TWT elements, their fields, and their values ​​by an IDC TWT SP responding AP and an IDC TWT SP requesting STA, respectively.

[0213]

[0214]

[0215]

[0216]

[0217] As shown in Table 1 and Table 2, the TWT element included in the frame transmitted by the IDC TWT SP requesting STA and the TWT element included in the frame transmitted by the IDC TWT SP responding AP may have the value of the broadcast TWT recommendation subfield as 5 or one of the other reserved values ​​to indicate the IDC TWT SP.

[0218] FIG. 17 is a diagram illustrating the operation of devices for an IDC TWT SP according to one embodiment of the present disclosure. FIG. 17 illustrates and describes a grouping process for one IDC TWT SP, in which STAs other than an IDC TWT SP requesting STA join membership for the IDC TWT SP.

[0219] According to the embodiment of FIG. 17, STA1 (i.e., IDC TWT SP requesting STA) transmits to AP (i.e., IDC TWT SP responding AP) a first frame including a TWT element whose broadcast TWT recommendation field has a specific value (one of the reserved values ​​5 to 7). AP approves the creation / establishment / setup of IDC TWT SP based on the TWT element included in the first frame received from STA1, and transmits to STA1 a second frame including a TWT element whose broadcast TWT recommendation field has a specific value (one of the reserved values ​​5 to 7). The first frame and the second frame may be a TWT setup frame as illustrated in FIG. 17, or may include other management frames, control frames, action frames, or new types of frames.

[0220] Subsequently, the AP transmits a third frame including information about the IDC TWT SP generated / configured / set up at the request of STA1, and including a TWT element whose broadcast TWT recommendation field has a specific value (one of the reserved values ​​5 to 7). This third frame can be broadcast to multiple STAs including STA1. STA1, STA2, and STA3 receiving the third frame can identify the IDC TWT SP generated / configured / set up by STA1 and the AP. The third frame may be a beacon frame as illustrated in FIG. 17, or may include other management frames, control frames, action frames, probe response frames, combined response frames, or new types of frames.

[0221] Each of STA2 and STA3 transmits a fourth frame to the AP, which includes a TWT element whose Broadcast TWT Recommendation field has a specific value (one of the reserved values ​​from 5 to 7) to join the IDC TWT SP created / established / set up between STA1 and the AP. The AP may transmit a fifth frame to each of STA2 and STA3, which includes a TWT element whose Broadcast TWT Recommendation field has a specific value (one of the reserved values ​​from 5 to 7) to confirm the joining of STA2 and STA3.

[0222] In the illustrated embodiment, STA1 and STA2 may subscribe to a broadcast TWT schedule and operate according to a synchronized IDC TWT SP, which may include operations to suspend, restrict, or minimize WLAN. STA3 may operate by performing IDC operations during the IDC TWT SP period to suspend, restrict, or minimize WLAN, and may also receive specific traffic (e.g., low-latency traffic) agreed upon in advance with the AP when the WLAN is ready.

[0223] Meanwhile, in the illustrated embodiment, STA1, STA2, and STA3 may be adjacent STAs as described above. Accordingly, STA1, STA2, and STA3, which subscribe to the same IDC TWT SP, may be connected to or communicate with each other via other wireless access technologies than WLAN. Accordingly, STA1, STA2, and STA3 may share or inform each other about specific parameters for the IDC TWT SP (e.g., the length of the time interval of the IDC TWT SP, the cycle of the IDC TWT SP, the start time of the IDC TWT SP, etc.). In particular, when STA1 creates / configures / sets up the IDC TWT SP through the IDC TWT SP setup procedure with the AP, STA1 may exchange or inform STA2 and STA3 of information about the IDC TWT SP via other wireless access technologies or communication methods. In addition, it goes without saying that STA1 may exchange or share the parameters of the IDC TWT SP it requests (i.e., needs) with STA2 and STA3 in advance before requesting the AP to create / configure / set up the IDC TWT SP.

[0224] To explain further about the first frame described above, the first frame transmitted by STA1 to the AP may include a TWT element including a broadcast TWT parameter set, and the parameters in the TWT element may include, for example, the following values.

[0225] TWT setup command field == 0, 1, or 2 (indicating accept, suggest, or demand)

[0226] TWT Request field == 1 (indicates the STA requesting IDC TWT SP setup)

[0227] Nominal Minimum TWT Wake Duration field == Indicates the time interval during which the WLAN is unavailable for IDC operation. The Nominal Minimum TWT Wake Duration field used in connection with the IDC TWT SP may also be referred to as the IDC Duration field.

[0228] Broadcast TWT Recommendation field == 5, 6, or 7 (This IDC TWT SP indicates that the IDC TWT SP requesting STA is unavailable due to activity of other radio access technologies, and that the IDC TWT SP requesting STA may not be able to individually respond to frames from the IDC TWT SP responding AP.)

[0229] TWT Wake Interval Mantissa / Exponent: Indicates the mantissa / exponent when the occurrence period value of the IDC TWT SP is expressed as a power of 2. The TWT Wake Interval Mantissa / Exponent field used in relation to the IDC TWT SP may also be called the IDC Interval Mantissa / Exponent field.

[0230] The AP may acknowledge the IDC TWT SP creation / configuration / setup request of STA1 and send a second frame for response to STA1. Through this second frame, the AP may inform STA1 that the IDC TWT SP requested by STA1 has been successfully created / configured / setup and is managed by the AP. A broadcast TWT ID included in the TWT element is assigned to this IDC TWT SP, so that the IDC TWT SP can be identified through the broadcast TWT ID, and this broadcast TWT ID may be referred to as an IDC TWT SP identifier.

[0231] The second frame transmitted by the AP to STA1 may include a TWT element including a broadcast TWT parameter set, and the parameters in the TWT element may include, for example, values ​​as follows.

[0232] TWT setup command field == 4 or 7 (indicates accept or reject)

[0233] TWT Request field == 0 (indicates AP authorizing IDC TWT SP setup)

[0234] Broadcast TWT Recommendation field == 5, 6, or 7 (indicates that the second frame is for IDC operation in the IDC TWT SP)

[0235] STA1 recognizes that the IDC TWT SP has been successfully created / configured / set up upon receiving the second frame from the AP, and can notify the result to other adjacent STAs, STA2 and STA3. This process can be performed via a wireless access technology other than WLAN, and STA1 can transmit the IDC SP identifier of the IDC TWT SP created / configured / set up by the AP to STA2 and STA3.

[0236] Prior to the start of the created / configured / setup IDC TWT SP, the AP may broadcast a third frame including information about the IDC TWT SP (e.g., schedule information of the IDC TWT SP) to other STAs within the BSS. The third frame transmitted by the AP may include one broadcast TWT parameter set for indicating information related to the schedule of the IDC TWT SP (e.g., start time of the IDC TWT SP, period of the IDC TWT SP, length of the IDC TWT SP, etc.). According to one embodiment, the third frame transmitted by the AP may include, in addition to the broadcast TWT parameter set for the created / configured / setup IDC TWT SP of STA1, broadcast TWT parameter sets for other IDC TWT SPs in the form of a list, and one or more broadcast TWT parameter sets may be distinguished by an IDC TWT SP identifier. When multiple broadcast TWT parameter sets are included in a list form within a TWT element, the last broadcast parameter set field value of the request type subfield for the last broadcast TWT parameter set in the list may be set to 1. In addition, such a list may also include broadcast TWT parameter sets for legacy broadcast TWT SPs in addition to broadcast TWT parameter sets for IDC TWT SPs. Broadcast TWT parameter sets for IDC TWT SPs may be distinguished by the IDC TWT SP identifier and / or the value of the broadcast TWT recommendation field.

[0237] STA2 and STA3, which received the third frame including the broadcast TWT parameter set, decide to join the IDC TWT SP based on the IDC TWT SP-related parameters included in the broadcast TWT parameter set, and transmit a fourth frame to the AP to request IDC TWT SP joining. The AP confirms and approves the joining requests from STA2 and STA3, and transmits a fifth frame for response to STA2 and STA3, respectively.

[0238] The following FIGS. 18 to 22 are flowcharts illustrating the operations of the STA and AP according to the various embodiments described in FIGS. 13 to 17 in chronological order. Accordingly, even without separate explanation, some or all of the embodiments described above can be applied identically or similarly to FIGS. 18 to 22.

[0239] FIG. 18 is a flowchart illustrating signaling of devices for IDC operation according to one embodiment of the present disclosure.

[0240] In step 1805, STA1 is located adjacent to STA2 and STA3 within the BSS of the AP, and STA1, STA2, and STA3 may perform IDC operations to suspend, limit, or minimize WLAN operations for other wireless access technologies. To this end, STA1, STA2, and STA3 may share and negotiate parameters for IDC operations in advance, and a common IDC TWT SP may be required for STA1, STA2, and STA3.

[0241] In step 1810, STA1 transmits a frame including a TWT parameter set in which IDC-related parameters are set to the AP. This TWT parameter set may include information or values ​​for generating an IDC TWT SP, and the broadcast TWT recommendation field included in the TWT parameter set may have one of the reserved values ​​5 to 7. In addition, the frame transmitted by STA1 may be a TWT setup frame, a management frame, a control frame, an action frame, or a new type of frame.

[0242] In step 1815, the AP transmits to STA1 a frame including a TWT parameter set in which IDC-related parameters are set. This TWT parameter set may include information or values ​​for indicating a response to authorizing the generation of an IDC TWT SP, and the broadcast TWT recommendation field included in the TWT parameter set may have one of the reserved values ​​5 to 7. In addition, the frame transmitted by the AP may be a TWT setup frame, a management frame, a control frame, an action frame, or a new type of frame.

[0243] At step 1820, STA1 may share or transmit information about the IDC TWT SP to STA2 and STA3 as the creation / configuration / setup of the IDC TWT SP is approved by the AP.

[0244] In step 1825, the AP broadcasts a frame containing parameters and information about the IDC TWT SP to announce information about the schedule of the created / configured / setup IDC TWT SP (e.g., start time, length, period, etc. of the IDC TWT SP). The frame broadcast by the AP may be a beacon frame, a probe response frame, a (re)association response frame, or other management frames, control frames, action frames, or new types of frames.

[0245] In step 1830, STA2, which obtains information about an IDC TWT SP from STA1 and wishes to join the IDC TWT SP, transmits a frame including a TWT parameter set in which IDC-related parameters are set to the AP. This TWT parameter set may include an identifier of an IDC TWT SP that the AP creates / configures / sets up and manages, and a broadcast TWT recommendation field included in the TWT parameter set may have a value of one of the reserved values ​​5 to 7. In addition, the frame transmitted by STA2 may be a TWT setup frame, a management frame, a control frame, an action frame, or a new type of frame.

[0246] In step 1835, the AP confirms that an IDC TWT SP has been assigned to STA2 at STA2's request. That is, the AP can notify that STA2's request to join the IDC TWT SP has been approved.

[0247] In step 1840, STA3, which obtains information about the IDC TWT SP from STA1 and wishes to join the IDC TWT SP, transmits a frame including a TWT parameter set in which IDC-related parameters are set to the AP. This TWT parameter set may include an identifier of an IDC TWT SP that the AP creates / configures / sets up and manages, and a broadcast TWT recommendation field included in the TWT parameter set may have a value of one of the reserved values ​​5 to 7. In addition, the frame transmitted by STA3 may be a TWT setup frame, a management frame, a control frame, an action frame, or a new type of frame.

[0248] In step 1845, the AP confirms that an IDC TWT SP has been assigned to STA3 at STA3's request. That is, the AP can notify that STA3's request to join the IDC TWT SP has been approved.

[0249] According to one embodiment, the operations described in steps 1830, 1835, 1840, and 1845 in the illustrated embodiment may or may not be selectively performed. For example, STA2 and STA3 may obtain parameters or information about an IDC TWT SP from STA1 and then perform IDC operations by joining membership for the corresponding IDC TWT SP according to the previously described embodiment. In another example, STA2 and STA3, which have obtained parameters or information about an IDC TWT SP from STA1, may identify the corresponding time interval even if they do not join the membership of the IDC TWT SP, and thus may perform the IDC operation in the time interval of the corresponding IDC TWT SP without performing the separate joining procedure described in steps 1830 to 1845.

[0250] In one embodiment, although not explicitly shown in FIG. 18, the AP may also modify or teardown a created / configured / setup IDC TWT SP.

[0251] Specifically, a non-AP STA can update related parameters of a previously generated IDC TWT SP. The frame for a non-AP STA to update an IDC TWT SP may be a TWT setup frame, an IDC update frame, or an IDC TWT update frame, and the frame that a non-AP STA transmits to an AP to update an IDC TWT SP may be any frame other than the examples described above. The frame that a non-AP STA transmits to an AP to update an IDC TWT SP may include an identifier of the IDC TWT SP to be updated, and may also include a TWT element including parameters or configuration values ​​of the IDC TWT SP to be updated. The TWT element that a non-AP STA transmits to an AP to update an IDC TWT SP may include at least one of a changed (or updated) nominal minimum TWT wake duration field (i.e., a changed WLAN unavailable time interval), or a changed TWT wake interval mantissa / exponent. An AP that receives a frame including a TWT element and / or a TWT parameter set to be updated from a non-AP STA may apply at least one of a changed (or updated) nominal minimum TWT wake duration field (or IDC duration field) or a TWT wake interval mantissa / exponent (or IDC interval mantissa / exponent) to an IDC TWT SP corresponding to an IDC TWT SP identifier included in the received frame. That is, the AP may manage the IDC TWT SP according to the changed (or updated) parameters and configuration values, and the non-AP STA may operate in the IDC TWT SP according to the changed (or updated) parameters and configuration values.

[0252] In order to change (or update) an IDC TWT SP in which multiple non-AP STAs participate (i.e., when multiple non-AP STAs have joined the membership of an IDC TWT SP), in the process described in step 1805, multiple non-AP STAs may share IDC-related information to be updated with each other and determine a non-AP STA that will transmit a frame for changing (or updating) the IDC TWT SP to the AP. According to this process, the non-AP STA that transmits a frame for requesting a change or update of the IDC TWT SP to the AP may be the non-AP STA described in step 1810 (i.e., STA1 of FIG. 18). According to one embodiment, the AP may limit or determine the non-AP STA that can request a change (or update) of the IDC TWT SP to be the same as the STA that transmits a frame for requesting creation / configuration / setup of the IDC TWT SP described in step 1810. According to this embodiment, when the AP receives a frame for requesting a change or update of an IDC TWT SP setting from a non-AP STA (e.g., a non-AP STA transmitting a frame requesting to join an IDC TWT SP in step 1830 or step 1840) other than the non-AP STA (i.e., STA1) that requested the IDC TWT SP creation / setting / setup in step 1810, the AP may additionally perform a procedure for confirming with STA1 about the setting or parameter to be changed or updated by transmitting a frame including a TWT element and a TWT parameter set including information related to the IDC TWT SP to be changed or updated to the IDC TWT SP requesting STA (i.e., STA1) that requested the IDC TWT SP creation / setting / setup.

[0253] In one embodiment, a non-AP STA may suspend, stop, or teardown a previously generated IDC TWT SP. In this embodiment, the frame transmitted by the non-AP STA to suspend, stop, stop, or teardown an IDC TWT SP may be a TWT release frame, an IDC release frame, an IDC TWT release frame, or any other frame other than these frames.

[0254] According to this embodiment, a frame for stopping, suspending, terminating or releasing an IDC TWT SP (e.g., a TWT release frame, an IDC release frame, or an IDC TWT release frame) may include an identifier of the IDC TWT SP to be stopped / suspended / terminated / released. An AP that receives a frame for stopping / suspending / terminating / releasing an IDC TWT SP may discard the IDC TWT SP and transmit a response frame (e.g., a TWT response frame, an IDC response frame, or an IDC TWT response frame) to the terminal, the response frame including an acknowledgment of the request of the non-AP STA or an identifier of the IDC TWT SP that has been stopped / suspended / terminated / releasing.

[0255] FIG. 19 is a flowchart illustrating the operation of a non-AP STA according to an embodiment of the present disclosure. In FIG. 19, various operations of the IDC TWT SP requesting STA described previously in FIGS. 13 to 18 may be applied identically or similarly, and detailed descriptions of any content that overlaps with the previously described content will be omitted.

[0256] According to the embodiment of FIG. 19, a non-AP STA (i.e., an IDC TWT SP requesting STA) transmits a frame to request an IDC TWT SP to an AP (i.e., an IDC TWT SP responding AP) (1910). The embodiments described above may be applied identically or similarly to various fields, formats, parameters, and values ​​included in the frame transmitted by the non-AP STA. For example, a broadcast TWT recommendation field included in a TWT element of a frame transmitted by the non-AP STA may include any one of reserved values ​​other than a predefined value.

[0257] A non-AP STA receives a frame from an AP for approving an IDC TWT SP (1920). The previously described embodiments may be applied identically or similarly to various fields, formats, parameters, and values ​​included in the frame received by the non-AP STA. For example, the broadcast TWT recommendation field included in the TWT element of the frame received by the non-AP STA may include any one of the reserved values ​​other than the predefined values.

[0258] A non-AP STA recognizes that an IDC TWT SP is created / configured / set up when a frame is received from an AP, and the non-AP STA can receive a frame broadcast from the AP to schedule or notify the IDC TWT SP (1930). The embodiments described above may be applied identically or similarly to various fields, formats, parameters, and values ​​included in the frame received by the non-AP STA. For example, a broadcast TWT recommendation field included in a TWT element of a frame received by the non-AP STA may include any one of reserved values ​​other than a predefined value.

[0259] A non-AP STA may perform IDC operations in an IDC TWT SP according to a frame broadcast by the AP (1940). For example, a non-AP STA may suspend, limit, or minimize WLAN in the IDC TWT SP, and may not receive or expect downlink scheduling from the AP, or may not receive or expect uplink triggering. In one embodiment, if a non-AP STA and an AP have agreed on specific traffic during the process of creating / configuring / setting up an IDC TWT SP, the non-AP STA may receive the traffic via WLAN even within the IDC TWT SP.

[0260] FIG. 20 is a flowchart illustrating the operation of an AP according to an embodiment of the present disclosure. In FIG. 20, various operations of the IDC TWT SP responding AP described previously in FIGS. 13 to 18 can be applied identically or similarly, and detailed descriptions of any content that overlaps with the previously described content are omitted.

[0261] According to the embodiment of FIG. 20, an AP (i.e., an IDC TWT SP responding AP) receives a frame for requesting an IDC TWT SP from a non-AP STA (i.e., an IDC TWT SP requesting STA) (2010). The embodiments described above may be applied identically or similarly to various fields, formats, parameters, and values ​​included in the frame received by the AP. For example, a broadcast TWT recommendation field included in a TWT element of a frame received by the AP may include any one of reserved values ​​other than a predefined value.

[0262] The AP transmits a frame to approve the IDC TWT SP to the non-AP (1920). The previously described embodiments may be applied identically or similarly to various fields, formats, parameters, and values ​​included in the frame transmitted by the AP. For example, the Broadcast TWT Recommendation field included in the TWT element of the frame transmitted by the AP may include any one of the reserved values ​​other than the predefined values.

[0263] As the AP creates / configures / sets up the IDC TWT SP, it can broadcast and transmit a frame to schedule or notify the IDC TWT SP to multiple STAs, including non-AP STAs (2030). The embodiments described above can be applied identically or similarly to various fields, formats, parameters, and values ​​included in the frame transmitted by the AP. For example, the broadcast TWT recommendation field included in the TWT element of the frame transmitted by the AP can include any one of the reserved values ​​other than the predefined values.

[0264] The AP may perform IDC operations in the IDC TWT SP according to the frames transmitted by broadcasting (2040). For example, the AP may expect that the WLAN of a non-AP STA is stopped, restricted, or minimized in the IDC TWT SP, and may not transmit a downlink scheduling or an uplink trigger to the non-AP STA. According to one embodiment, if the AP and the non-AP STA have agreed on specific traffic during the process of creating / configuring / setting up the IDC TWT SP, the AP may receive the traffic from the non-AP STA via the WLAN even within the IDC TWT SP.

[0265] FIG. 21 is a flowchart illustrating the operation of a non-AP STA according to an embodiment of the present disclosure. In FIG. 21, various operations of the IDC TWT SP requesting STA described previously in FIGS. 13 to 18 may be applied identically or similarly, and detailed descriptions of any content that overlaps with the previously described content will be omitted.

[0266] According to the embodiment of FIG. 21, a non-AP STA shares IDC-related information with another non-AP STA (i.e., an IDC TWT SP requesting STA) (2110). The process of a non-AP STA sharing IDC-related information with an IDC TWT SP requesting STA is optional and may be omitted in the embodiment of FIG. 21. A non-AP STA that receives IDC-related information from an IDC TWT SP requesting STA can recognize that an AP (i.e., an IDC TWT SP responding AP) creates / configures / sets up and manages an IDC TWT SP.

[0267] A non-AP STA may receive a frame broadcast from an AP to schedule or announce an IDC TWT SP (2120). The aforementioned embodiments may be applied identically or similarly to various fields, formats, parameters, and values ​​included in the frame received by the non-AP STA. For example, a broadcast TWT recommendation field included in a TWT element of a frame received by the non-AP STA may include any one of the reserved values ​​other than the predefined values.

[0268] A non-AP STA may transmit a frame to the AP to join a membership associated with an IDC TWT SP (2130). The previously described embodiments may be applied identically or similarly to various fields, formats, parameters, and values ​​included in the frame transmitted by the non-AP STA. For example, a broadcast TWT recommendation field included in a TWT element of a frame transmitted by the non-AP STA may include a value among reserved values ​​other than predefined values. In addition, a TWT element of a frame transmitted by the non-AP STA may include an identifier of an IDC TWT SP that the non-AP STA obtains from an IDC TWT SP requesting STA and wishes to join.

[0269] A non-AP STA can receive a frame from the AP to confirm membership in an IDC TWT SP (2140). That is, the non-AP STA can determine that it is a member STA of the IDC TWT SP by successfully completing membership in the IDC TWT SP. The embodiments described above can be applied identically or similarly to various fields, formats, parameters, and values ​​included in the frame received by the non-AP STA. For example, the broadcast TWT recommendation field included in the TWT element of the frame received by the non-AP STA can include any one of the reserved values ​​other than the predefined values.

[0270] A non-AP STA may perform IDC operations in an IDC TWT SP (2150). For example, a non-AP STA may suspend, limit, or minimize WLAN in an IDC TWT SP, and may not receive or expect downlink scheduling from an AP, or may not receive or expect uplink triggering. In one embodiment, if a non-AP STA and an AP have agreed on specific traffic during the process of creating / configuring / setting up an IDC TWT SP, the non-AP STA may receive the traffic over the WLAN even within the IDC TWT SP.

[0271] According to one embodiment, steps 2130 and 2140 described above may be optionally performed and omitted from the embodiment of FIG. 21. That is, a non-AP STA may obtain information about an IDC TWT SP from an IDC TWT SP requesting STA and perform IDC operations on the IDC TWT SP without joining the membership of the IDC TWT SP.

[0272] FIG. 22 is a flowchart illustrating the operation of an AP according to an embodiment of the present disclosure. In FIG. 22, various operations of the IDC TWT SP requesting STA described previously in FIGS. 13 to 18 may be applied identically or similarly, and detailed descriptions of any content that overlaps with the previously described content will be omitted.

[0273] According to the embodiment of FIG. 22, an AP (i.e., an IDC TWT SP responding AP) can broadcast and transmit a frame to a non-AP STA to schedule or notify an IDC TWT SP (2210). The embodiments described above can be applied identically or similarly to various fields, formats, parameters, and values ​​included in the frame transmitted by the AP. For example, a broadcast TWT recommendation field included in a TWT element of a frame transmitted by the AP can include any one of the reserved values ​​other than the predefined values.

[0274] An AP may receive a frame for joining a membership associated with an IDC TWT SP from a non-AP STA (2220). The aforementioned embodiments may be applied identically or similarly to various fields, formats, parameters, and values ​​included in the frame received by the AP. For example, a broadcast TWT recommendation field included in a TWT element of a frame received by the AP may include a value among reserved values ​​other than predefined values. In addition, a TWT element of a frame received by the AP may include an identifier of an IDC TWT SP that a non-AP STA obtains from an IDC TWT SP requesting STA and wishes to join.

[0275] The AP may transmit a frame to a non-AP STA to confirm membership in the IDC TWT SP (2230). That is, the AP may determine that the non-AP STA has successfully completed membership in the IDC TWT SP and that the non-AP STA has become a member STA. The embodiments described above may be applied identically or similarly to various fields, formats, parameters, and values ​​included in the frame transmitted by the AP. For example, the broadcast TWT recommendation field included in the TWT element of the frame transmitted by the AP may include any one of the reserved values ​​other than the predefined values.

[0276] The AP may perform IDC operations in the IDC TWT SP according to the frames transmitted by broadcasting (2240). For example, the AP may expect that the WLAN of a non-AP STA is stopped, restricted, or minimized in the IDC TWT SP, and may not transmit a downlink scheduling or an uplink trigger to the non-AP STA. According to one embodiment, if the AP and the non-AP STA have agreed on specific traffic during the process of creating / configuring / setting up the IDC TWT SP, the AP may receive the traffic from the non-AP STA via the WLAN even within the IDC TWT SP.

[0277] According to one embodiment, steps 2220 and 2230 described above may be optionally performed and omitted in the embodiment of FIG. 22.

[0278] 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.

[0279] 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 transmitting a first frame to an AP (access point) to request setup of an IDC (in-device coexistence) TWT (target wakeup time) SP (service period); A step of receiving a second frame for approving the setup of the IDC TWT SP from the AP; and Comprising a step of performing an IDC operation within the IDC TWT SP, The broadcast TWT recommendation field of the first TWT element included in the first frame includes a first value for indicating that the TWT SP associated with the first frame is the IDC TWT SP, A method, wherein the broadcast TWT recommendation field of the second TWT element included in the second frame includes a second value for indicating that the TWT SP associated with the second frame is the IDC TWT SP.

2. In paragraph 1, A method wherein the first value and the second value include any one of 5, 6, or 7, which are reserved values ​​for the broadcast TWT recommendation field.

3. In paragraph 1, The above IDC action includes at least one of stopping, limiting, or minimizing the WLAN, A method in which traffic negotiated between the STA and the AP for the IDC TWT SP is received regardless of the suspension, restriction, or minimization of the WLAN.

4. In paragraph 1, The above method, A method further comprising the step of receiving a third frame broadcast from the AP to schedule the IDC TWT SP.

5. In a method performed by an AP (access point) of a wireless local area network (WLAN) system, A step of receiving a first frame for requesting setup of an IDC (in-device coexistence) TWT (target wakeup time) SP (service period) from a STA (station); A step of transmitting a second frame to the STA to approve the setup of the IDC TWT SP; and Comprising a step of performing an IDC operation within the IDC TWT SP, The broadcast TWT recommendation field of the first TWT element included in the first frame includes a first value for indicating that the TWT SP associated with the first frame is the IDC TWT SP, A method, wherein the broadcast TWT recommendation field of the second TWT element included in the second frame includes a second value for indicating that the TWT SP associated with the second frame is the IDC TWT SP.

6. In paragraph 5, A method wherein the first value and the second value include any one of 5, 6, or 7, which are reserved values ​​for the broadcast TWT recommendation field.

7. In paragraph 5, The above IDC operation includes at least one of omission of scheduling or omission of triggering for the STA, A method in which traffic agreed upon between the STA and the AP for the IDC TWT SP is transmitted regardless of omission of the scheduling or omission of the triggering.

8. In the STA (station) of a wireless local area network (WLAN) system, 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: The first frame is transmitted to the AP (access point) to request setup of IDC (in-device coexistence), TWT (target wakeup time), and SP (service period). Receive a second frame from the AP to approve the setup of the IDC TWT SP; It is set to perform IDC operation within the above IDC TWT SP, The broadcast TWT recommendation field of the first TWT element included in the first frame includes a first value for indicating that the TWT SP associated with the first frame is the IDC TWT SP, A STA in which the broadcast TWT recommendation field of the second TWT element included in the second frame includes a second value for indicating that the TWT SP associated with the second frame is the IDC TWT SP.

9. In paragraph 8, STA, wherein the first value and the second value include any one of 5, 6, or 7, which are reserved values ​​for the broadcast TWT recommendation field.

10. In paragraph 8, The above IDC action includes at least one of stopping, limiting, or minimizing the WLAN, The traffic negotiated between the STA and the AP for the above IDC TWT SP is received regardless of the cessation, restriction, or minimization of the WLAN.

11. In paragraph 8, The above commands are: An STA that receives a third frame broadcast from the AP to schedule the IDC TWT SP.

12. In the AP (access point) of a wireless local area network (WLAN) system, 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: Receive the first frame from the STA (station) to request setup of IDC (in-device coexistence), TWT (target wakeup time), and SP (service period). Transmitting a second frame to the STA to approve the setup of the IDC TWT SP; It is set to perform IDC operation within the above IDC TWT SP, The broadcast TWT recommendation field of the first TWT element included in the first frame includes a first value for indicating that the TWT SP associated with the first frame is the IDC TWT SP, An AP in which the broadcast TWT recommendation field of the second TWT element included in the second frame includes a second value for indicating that the TWT SP associated with the second frame is the IDC TWT SP.

13. In paragraph 12, An AP wherein the first value and the second value include any one of 5, 6, or 7, which are reserved values ​​for the broadcast TWT recommendation field.

14. In paragraph 12, The above IDC operation includes at least one of omission of scheduling or omission of triggering for the STA, An AP in which traffic agreed upon between the STA and the AP for the IDC TWT SP is transmitted regardless of omission of the scheduling or omission of the triggering.

15. In paragraph 12, The above commands cause the AP to: An AP that broadcasts a third frame to schedule the above IDC TWT SP.

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